Merge github.com:grpc/grpc into bugscrub1-proposedfix1

70 files changed, 1781 insertions, 847 deletions

diff --git a/src/core/lib/channel/connected_channel.c b/src/core/lib/channel/connected_channel.c
index 42ef7b7806..75c68a5534 100644
--- a/src/core/lib/channel/connected_channel.c
+++ b/src/core/lib/channel/connected_channel.c
@@ -90,7 +90,8 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
       exec_ctx, chand->transport, TRANSPORT_STREAM_FROM_CALL_DATA(calld),
       &args->call_stack->refcount, args->server_transport_data, args->arena);
   return r == 0 ? GRPC_ERROR_NONE
-                : GRPC_ERROR_CREATE("transport stream initialization failed");
+                : GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                      "transport stream initialization failed");
 }
 
 static void set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
diff --git a/src/core/lib/channel/deadline_filter.c b/src/core/lib/channel/deadline_filter.c
index 34114bbebf..ca701ed457 100644
--- a/src/core/lib/channel/deadline_filter.c
+++ b/src/core/lib/channel/deadline_filter.c
@@ -55,9 +55,9 @@ static void timer_callback(grpc_exec_ctx* exec_ctx, void* arg,
   if (error != GRPC_ERROR_CANCELLED) {
     grpc_call_element_signal_error(
         exec_ctx, elem,
-        grpc_error_set_int(GRPC_ERROR_CREATE("Deadline Exceeded"),
-                           GRPC_ERROR_INT_GRPC_STATUS,
-                           GRPC_STATUS_DEADLINE_EXCEEDED));
+        grpc_error_set_int(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Deadline Exceeded"),
+            GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_DEADLINE_EXCEEDED));
   }
   GRPC_CALL_STACK_UNREF(exec_ctx, deadline_state->call_stack, "deadline_timer");
 }
diff --git a/src/core/lib/channel/handshaker.c b/src/core/lib/channel/handshaker.c
index 1b4240bb10..5861fa6f54 100644
--- a/src/core/lib/channel/handshaker.c
+++ b/src/core/lib/channel/handshaker.c
@@ -236,8 +236,9 @@ static void call_next_handshaker(grpc_exec_ctx* exec_ctx, void* arg,
 static void on_timeout(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
   grpc_handshake_manager* mgr = arg;
   if (error == GRPC_ERROR_NONE) {  // Timer fired, rather than being cancelled.
-    grpc_handshake_manager_shutdown(exec_ctx, mgr,
-                                    GRPC_ERROR_CREATE("Handshake timed out"));
+    grpc_handshake_manager_shutdown(
+        exec_ctx, mgr,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Handshake timed out"));
   }
   grpc_handshake_manager_unref(exec_ctx, mgr);
 }
diff --git a/src/core/lib/channel/http_client_filter.c b/src/core/lib/channel/http_client_filter.c
index f9d0d689ac..967904df1e 100644
--- a/src/core/lib/channel/http_client_filter.c
+++ b/src/core/lib/channel/http_client_filter.c
@@ -36,6 +36,7 @@
 #include <grpc/support/string_util.h>
 #include <string.h>
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/security/util/b64.h"
 #include "src/core/lib/slice/percent_encoding.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
@@ -56,7 +57,6 @@ typedef struct call_data {
   grpc_linked_mdelem te_trailers;
   grpc_linked_mdelem content_type;
   grpc_linked_mdelem user_agent;
-  grpc_linked_mdelem payload_bin;
 
   grpc_metadata_batch *recv_initial_metadata;
   grpc_metadata_batch *recv_trailing_metadata;
@@ -108,11 +108,11 @@ static grpc_error *client_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
       grpc_error *e = grpc_error_set_str(
           grpc_error_set_int(
               grpc_error_set_str(
-                  GRPC_ERROR_CREATE(
+                  GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                       "Received http2 :status header with non-200 OK status"),
-                  GRPC_ERROR_STR_VALUE, val),
+                  GRPC_ERROR_STR_VALUE, grpc_slice_from_copied_string(val)),
               GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_CANCELLED),
-          GRPC_ERROR_STR_GRPC_MESSAGE, msg);
+          GRPC_ERROR_STR_GRPC_MESSAGE, grpc_slice_from_copied_string(msg));
       gpr_free(val);
       gpr_free(msg);
       return e;
@@ -292,19 +292,58 @@ static grpc_error *hc_mutate_op(grpc_exec_ctx *exec_ctx,
       continue_send_message(exec_ctx, elem);
 
       if (calld->send_message_blocked == false) {
-        /* when all the send_message data is available, then create a MDELEM and
-        append to headers */
-        grpc_mdelem payload_bin = grpc_mdelem_from_slices(
-            exec_ctx, GRPC_MDSTR_GRPC_PAYLOAD_BIN,
-            grpc_slice_from_copied_buffer((const char *)calld->payload_bytes,
-                                          op->send_message->length));
-        error =
-            grpc_metadata_batch_add_tail(exec_ctx, op->send_initial_metadata,
-                                         &calld->payload_bin, payload_bin);
+        /* when all the send_message data is available, then modify the path
+         * MDELEM by appending base64 encoded query to the path */
+        const int k_url_safe = 1;
+        const int k_multi_line = 0;
+        const unsigned char k_query_separator = '?';
+
+        grpc_slice path_slice =
+            GRPC_MDVALUE(op->send_initial_metadata->idx.named.path->md);
+        /* sum up individual component's lengths and allocate enough memory to
+         * hold combined path+query */
+        size_t estimated_len = GRPC_SLICE_LENGTH(path_slice);
+        estimated_len++; /* for the '?' */
+        estimated_len += grpc_base64_estimate_encoded_size(
+            op->send_message->length, k_url_safe, k_multi_line);
+        estimated_len += 1; /* for the trailing 0 */
+        grpc_slice path_with_query_slice = grpc_slice_malloc(estimated_len);
+
+        /* memcopy individual pieces into this slice */
+        uint8_t *write_ptr =
+            (uint8_t *)GRPC_SLICE_START_PTR(path_with_query_slice);
+        uint8_t *original_path = (uint8_t *)GRPC_SLICE_START_PTR(path_slice);
+        memcpy(write_ptr, original_path, GRPC_SLICE_LENGTH(path_slice));
+        write_ptr += GRPC_SLICE_LENGTH(path_slice);
+
+        *write_ptr = k_query_separator;
+        write_ptr++; /* for the '?' */
+
+        grpc_base64_encode_core((char *)write_ptr, calld->payload_bytes,
+                                op->send_message->length, k_url_safe,
+                                k_multi_line);
+
+        /* remove trailing unused memory and add trailing 0 to terminate string
+         */
+        char *t = (char *)GRPC_SLICE_START_PTR(path_with_query_slice);
+        /* safe to use strlen since base64_encode will always add '\0' */
+        size_t path_length = strlen(t) + 1;
+        *(t + path_length) = '\0';
+        path_with_query_slice =
+            grpc_slice_sub(path_with_query_slice, 0, path_length);
+
+        /* substitute previous path with the new path+query */
+        grpc_mdelem mdelem_path_and_query = grpc_mdelem_from_slices(
+            exec_ctx, GRPC_MDSTR_PATH, path_with_query_slice);
+        grpc_metadata_batch *b = op->send_initial_metadata;
+        error = grpc_metadata_batch_substitute(exec_ctx, b, b->idx.named.path,
+                                               mdelem_path_and_query);
         if (error != GRPC_ERROR_NONE) return error;
+
         calld->on_complete = op->on_complete;
         op->on_complete = &calld->hc_on_complete;
         op->send_message = NULL;
+        grpc_slice_unref_internal(exec_ctx, path_with_query_slice);
       } else {
         /* Not all data is available. Fall back to POST. */
         gpr_log(GPR_DEBUG,
diff --git a/src/core/lib/channel/http_server_filter.c b/src/core/lib/channel/http_server_filter.c
index bebd3af335..8d3c488ea0 100644
--- a/src/core/lib/channel/http_server_filter.c
+++ b/src/core/lib/channel/http_server_filter.c
@@ -37,6 +37,7 @@
 #include <grpc/support/log.h>
 #include <string.h>
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/security/util/b64.h"
 #include "src/core/lib/slice/percent_encoding.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
@@ -51,8 +52,8 @@ typedef struct call_data {
   grpc_linked_mdelem status;
   grpc_linked_mdelem content_type;
 
-  /* did this request come with payload-bin */
-  bool seen_payload_bin;
+  /* did this request come with path query containing request payload */
+  bool seen_path_with_query;
   /* flag to ensure payload_bin is delivered only once */
   bool payload_bin_delivered;
 
@@ -61,7 +62,7 @@ typedef struct call_data {
   bool *recv_cacheable_request;
   /** Closure to call when finished with the hs_on_recv hook */
   grpc_closure *on_done_recv;
-  /** Closure to call when we retrieve read message from the payload-bin header
+  /** Closure to call when we retrieve read message from the path URI
    */
   grpc_closure *recv_message_ready;
   grpc_closure *on_complete;
@@ -101,7 +102,7 @@ static void add_error(const char *error_name, grpc_error **cumulative,
                       grpc_error *new) {
   if (new == GRPC_ERROR_NONE) return;
   if (*cumulative == GRPC_ERROR_NONE) {
-    *cumulative = GRPC_ERROR_CREATE(error_name);
+    *cumulative = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_name);
   }
   *cumulative = grpc_error_add_child(*cumulative, new);
 }
@@ -125,27 +126,32 @@ static grpc_error *server_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
       *calld->recv_cacheable_request = true;
     } else {
       add_error(error_name, &error,
-                grpc_attach_md_to_error(GRPC_ERROR_CREATE("Bad header"),
-                                        b->idx.named.method->md));
+                grpc_attach_md_to_error(
+                    GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad header"),
+                    b->idx.named.method->md));
     }
     grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.method);
   } else {
-    add_error(error_name, &error,
-              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
-                                 GRPC_ERROR_STR_KEY, ":method"));
+    add_error(
+        error_name, &error,
+        grpc_error_set_str(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+            GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":method")));
   }
 
   if (b->idx.named.te != NULL) {
     if (!grpc_mdelem_eq(b->idx.named.te->md, GRPC_MDELEM_TE_TRAILERS)) {
       add_error(error_name, &error,
-                grpc_attach_md_to_error(GRPC_ERROR_CREATE("Bad header"),
-                                        b->idx.named.te->md));
+                grpc_attach_md_to_error(
+                    GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad header"),
+                    b->idx.named.te->md));
     }
     grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.te);
   } else {
     add_error(error_name, &error,
-              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
-                                 GRPC_ERROR_STR_KEY, "te"));
+              grpc_error_set_str(
+                  GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+                  GRPC_ERROR_STR_KEY, grpc_slice_from_static_string("te")));
   }
 
   if (b->idx.named.scheme != NULL) {
@@ -153,14 +159,17 @@ static grpc_error *server_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
         !grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_HTTPS) &&
         !grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_GRPC)) {
       add_error(error_name, &error,
-                grpc_attach_md_to_error(GRPC_ERROR_CREATE("Bad header"),
-                                        b->idx.named.scheme->md));
+                grpc_attach_md_to_error(
+                    GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad header"),
+                    b->idx.named.scheme->md));
     }
     grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.scheme);
   } else {
-    add_error(error_name, &error,
-              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
-                                 GRPC_ERROR_STR_KEY, ":scheme"));
+    add_error(
+        error_name, &error,
+        grpc_error_set_str(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+            GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":scheme")));
   }
 
   if (b->idx.named.content_type != NULL) {
@@ -194,8 +203,46 @@ static grpc_error *server_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
 
   if (b->idx.named.path == NULL) {
     add_error(error_name, &error,
-              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
-                                 GRPC_ERROR_STR_KEY, ":path"));
+              grpc_error_set_str(
+                  GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+                  GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":path")));
+  } else if (*calld->recv_cacheable_request == true) {
+    /* We have a cacheable request made with GET verb. The path contains the
+     * query parameter which is base64 encoded request payload. */
+    const char k_query_separator = '?';
+    grpc_slice path_slice = GRPC_MDVALUE(b->idx.named.path->md);
+    uint8_t *path_ptr = (uint8_t *)GRPC_SLICE_START_PTR(path_slice);
+    size_t path_length = GRPC_SLICE_LENGTH(path_slice);
+    /* offset of the character '?' */
+    size_t offset = 0;
+    for (offset = 0; *path_ptr != k_query_separator && offset < path_length;
+         path_ptr++, offset++)
+      ;
+    if (offset < path_length) {
+      grpc_slice query_slice =
+          grpc_slice_sub(path_slice, offset + 1, path_length);
+
+      /* substitute path metadata with just the path (not query) */
+      grpc_mdelem mdelem_path_without_query = grpc_mdelem_from_slices(
+          exec_ctx, GRPC_MDSTR_PATH, grpc_slice_sub(path_slice, 0, offset));
+
+      grpc_metadata_batch_substitute(exec_ctx, b, b->idx.named.path,
+                                     mdelem_path_without_query);
+
+      /* decode payload from query and add to the slice buffer to be returned */
+      const int k_url_safe = 1;
+      grpc_slice_buffer_add(
+          &calld->read_slice_buffer,
+          grpc_base64_decode(exec_ctx,
+                             (const char *)GRPC_SLICE_START_PTR(query_slice),
+                             k_url_safe));
+      grpc_slice_buffer_stream_init(&calld->read_stream,
+                                    &calld->read_slice_buffer, 0);
+      calld->seen_path_with_query = true;
+      grpc_slice_unref_internal(exec_ctx, query_slice);
+    } else {
+      gpr_log(GPR_ERROR, "GET request without QUERY");
+    }
   }
 
   if (b->idx.named.host != NULL && b->idx.named.authority == NULL) {
@@ -212,19 +259,11 @@ static grpc_error *server_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
   }
 
   if (b->idx.named.authority == NULL) {
-    add_error(error_name, &error,
-              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
-                                 GRPC_ERROR_STR_KEY, ":authority"));
-  }
-
-  if (b->idx.named.grpc_payload_bin != NULL) {
-    calld->seen_payload_bin = true;
-    grpc_slice_buffer_add(&calld->read_slice_buffer,
-                          grpc_slice_ref_internal(
-                              GRPC_MDVALUE(b->idx.named.grpc_payload_bin->md)));
-    grpc_slice_buffer_stream_init(&calld->read_stream,
-                                  &calld->read_slice_buffer, 0);
-    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.grpc_payload_bin);
+    add_error(
+        error_name, &error,
+        grpc_error_set_str(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+            GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":authority")));
   }
 
   return error;
@@ -247,8 +286,8 @@ static void hs_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
                            grpc_error *err) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
-  /* Call recv_message_ready if we got the payload via the header field */
-  if (calld->seen_payload_bin && calld->recv_message_ready != NULL) {
+  /* Call recv_message_ready if we got the payload via the path field */
+  if (calld->seen_path_with_query && calld->recv_message_ready != NULL) {
     *calld->pp_recv_message = calld->payload_bin_delivered
                                   ? NULL
                                   : (grpc_byte_stream *)&calld->read_stream;
@@ -263,7 +302,7 @@ static void hs_recv_message_ready(grpc_exec_ctx *exec_ctx, void *user_data,
                                   grpc_error *err) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
-  if (calld->seen_payload_bin) {
+  if (calld->seen_path_with_query) {
     /* do nothing. This is probably a GET request, and payload will be returned
     in hs_on_complete callback. */
   } else {
diff --git a/src/core/lib/channel/message_size_filter.c b/src/core/lib/channel/message_size_filter.c
index 5ba13fe251..63136650a5 100644
--- a/src/core/lib/channel/message_size_filter.c
+++ b/src/core/lib/channel/message_size_filter.c
@@ -121,8 +121,8 @@ static void recv_message_ready(grpc_exec_ctx* exec_ctx, void* user_data,
                  "Received message larger than max (%u vs. %d)",
                  (*calld->recv_message)->length, calld->max_recv_size);
     grpc_error* new_error = grpc_error_set_int(
-        GRPC_ERROR_CREATE(message_string), GRPC_ERROR_INT_GRPC_STATUS,
-        GRPC_STATUS_INVALID_ARGUMENT);
+        GRPC_ERROR_CREATE_FROM_COPIED_STRING(message_string),
+        GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_INVALID_ARGUMENT);
     if (error == GRPC_ERROR_NONE) {
       error = new_error;
     } else {
@@ -147,9 +147,10 @@ static void start_transport_stream_op(grpc_exec_ctx* exec_ctx,
     gpr_asprintf(&message_string, "Sent message larger than max (%u vs. %d)",
                  op->send_message->length, calld->max_send_size);
     grpc_transport_stream_op_finish_with_failure(
-        exec_ctx, op, grpc_error_set_int(GRPC_ERROR_CREATE(message_string),
-                                         GRPC_ERROR_INT_GRPC_STATUS,
-                                         GRPC_STATUS_INVALID_ARGUMENT));
+        exec_ctx, op,
+        grpc_error_set_int(GRPC_ERROR_CREATE_FROM_COPIED_STRING(message_string),
+                           GRPC_ERROR_INT_GRPC_STATUS,
+                           GRPC_STATUS_INVALID_ARGUMENT));
     gpr_free(message_string);
     return;
   }
diff --git a/src/core/lib/http/httpcli.c b/src/core/lib/http/httpcli.c
index 6d7aa43b81..453a64b049 100644
--- a/src/core/lib/http/httpcli.c
+++ b/src/core/lib/http/httpcli.c
@@ -126,13 +126,15 @@ static void finish(grpc_exec_ctx *exec_ctx, internal_request *req,
 
 static void append_error(internal_request *req, grpc_error *error) {
   if (req->overall_error == GRPC_ERROR_NONE) {
-    req->overall_error = GRPC_ERROR_CREATE("Failed HTTP/1 client request");
+    req->overall_error =
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed HTTP/1 client request");
   }
   grpc_resolved_address *addr = &req->addresses->addrs[req->next_address - 1];
   char *addr_text = grpc_sockaddr_to_uri(addr);
   req->overall_error = grpc_error_add_child(
       req->overall_error,
-      grpc_error_set_str(error, GRPC_ERROR_STR_TARGET_ADDRESS, addr_text));
+      grpc_error_set_str(error, GRPC_ERROR_STR_TARGET_ADDRESS,
+                         grpc_slice_from_copied_string(addr_text)));
   gpr_free(addr_text);
 }
 
@@ -190,8 +192,8 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
   internal_request *req = arg;
 
   if (!ep) {
-    next_address(exec_ctx, req,
-                 GRPC_ERROR_CREATE("Unexplained handshake failure"));
+    next_address(exec_ctx, req, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                    "Unexplained handshake failure"));
     return;
   }
 
@@ -221,8 +223,8 @@ static void next_address(grpc_exec_ctx *exec_ctx, internal_request *req,
   }
   if (req->next_address == req->addresses->naddrs) {
     finish(exec_ctx, req,
-           GRPC_ERROR_CREATE_REFERENCING("Failed HTTP requests to all targets",
-                                         &req->overall_error, 1));
+           GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+               "Failed HTTP requests to all targets", &req->overall_error, 1));
     return;
   }
   addr = &req->addresses->addrs[req->next_address++];
diff --git a/src/core/lib/http/httpcli_security_connector.c b/src/core/lib/http/httpcli_security_connector.c
index 354d2f4a09..be6a6d618a 100644
--- a/src/core/lib/http/httpcli_security_connector.c
+++ b/src/core/lib/http/httpcli_security_connector.c
@@ -95,7 +95,7 @@ static void httpcli_ssl_check_peer(grpc_exec_ctx *exec_ctx,
     char *msg;
     gpr_asprintf(&msg, "Peer name %s is not in peer certificate",
                  c->secure_peer_name);
-    error = GRPC_ERROR_CREATE(msg);
+    error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
     gpr_free(msg);
   }
   grpc_closure_sched(exec_ctx, on_peer_checked, error);
diff --git a/src/core/lib/http/parser.c b/src/core/lib/http/parser.c
index b9c56c103c..aac506b800 100644
--- a/src/core/lib/http/parser.c
+++ b/src/core/lib/http/parser.c
@@ -54,26 +54,36 @@ static grpc_error *handle_response_line(grpc_http_parser *parser) {
   uint8_t *cur = beg;
   uint8_t *end = beg + parser->cur_line_length;
 
-  if (cur == end || *cur++ != 'H') return GRPC_ERROR_CREATE("Expected 'H'");
-  if (cur == end || *cur++ != 'T') return GRPC_ERROR_CREATE("Expected 'T'");
-  if (cur == end || *cur++ != 'T') return GRPC_ERROR_CREATE("Expected 'T'");
-  if (cur == end || *cur++ != 'P') return GRPC_ERROR_CREATE("Expected 'P'");
-  if (cur == end || *cur++ != '/') return GRPC_ERROR_CREATE("Expected '/'");
-  if (cur == end || *cur++ != '1') return GRPC_ERROR_CREATE("Expected '1'");
-  if (cur == end || *cur++ != '.') return GRPC_ERROR_CREATE("Expected '.'");
+  if (cur == end || *cur++ != 'H')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected 'H'");
+  if (cur == end || *cur++ != 'T')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected 'T'");
+  if (cur == end || *cur++ != 'T')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected 'T'");
+  if (cur == end || *cur++ != 'P')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected 'P'");
+  if (cur == end || *cur++ != '/')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected '/'");
+  if (cur == end || *cur++ != '1')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected '1'");
+  if (cur == end || *cur++ != '.')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected '.'");
   if (cur == end || *cur < '0' || *cur++ > '1') {
-    return GRPC_ERROR_CREATE("Expected HTTP/1.0 or HTTP/1.1");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Expected HTTP/1.0 or HTTP/1.1");
   }
-  if (cur == end || *cur++ != ' ') return GRPC_ERROR_CREATE("Expected ' '");
+  if (cur == end || *cur++ != ' ')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected ' '");
   if (cur == end || *cur < '1' || *cur++ > '9')
-    return GRPC_ERROR_CREATE("Expected status code");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected status code");
   if (cur == end || *cur < '0' || *cur++ > '9')
-    return GRPC_ERROR_CREATE("Expected status code");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected status code");
   if (cur == end || *cur < '0' || *cur++ > '9')
-    return GRPC_ERROR_CREATE("Expected status code");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected status code");
   parser->http.response->status =
       (cur[-3] - '0') * 100 + (cur[-2] - '0') * 10 + (cur[-1] - '0');
-  if (cur == end || *cur++ != ' ') return GRPC_ERROR_CREATE("Expected ' '");
+  if (cur == end || *cur++ != ' ')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected ' '");
 
   /* we don't really care about the status code message */
 
@@ -89,24 +99,33 @@ static grpc_error *handle_request_line(grpc_http_parser *parser) {
 
   while (cur != end && *cur++ != ' ')
     ;
-  if (cur == end) return GRPC_ERROR_CREATE("No method on HTTP request line");
+  if (cur == end)
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "No method on HTTP request line");
   parser->http.request->method = buf2str(beg, (size_t)(cur - beg - 1));
 
   beg = cur;
   while (cur != end && *cur++ != ' ')
     ;
-  if (cur == end) return GRPC_ERROR_CREATE("No path on HTTP request line");
+  if (cur == end)
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("No path on HTTP request line");
   parser->http.request->path = buf2str(beg, (size_t)(cur - beg - 1));
 
-  if (cur == end || *cur++ != 'H') return GRPC_ERROR_CREATE("Expected 'H'");
-  if (cur == end || *cur++ != 'T') return GRPC_ERROR_CREATE("Expected 'T'");
-  if (cur == end || *cur++ != 'T') return GRPC_ERROR_CREATE("Expected 'T'");
-  if (cur == end || *cur++ != 'P') return GRPC_ERROR_CREATE("Expected 'P'");
-  if (cur == end || *cur++ != '/') return GRPC_ERROR_CREATE("Expected '/'");
+  if (cur == end || *cur++ != 'H')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected 'H'");
+  if (cur == end || *cur++ != 'T')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected 'T'");
+  if (cur == end || *cur++ != 'T')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected 'T'");
+  if (cur == end || *cur++ != 'P')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected 'P'");
+  if (cur == end || *cur++ != '/')
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Expected '/'");
   vers_major = (uint8_t)(*cur++ - '1' + 1);
   ++cur;
   if (cur == end)
-    return GRPC_ERROR_CREATE("End of line in HTTP version string");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "End of line in HTTP version string");
   vers_minor = (uint8_t)(*cur++ - '1' + 1);
 
   if (vers_major == 1) {
@@ -115,18 +134,19 @@ static grpc_error *handle_request_line(grpc_http_parser *parser) {
     } else if (vers_minor == 1) {
       parser->http.request->version = GRPC_HTTP_HTTP11;
     } else {
-      return GRPC_ERROR_CREATE(
+      return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
           "Expected one of HTTP/1.0, HTTP/1.1, or HTTP/2.0");
     }
   } else if (vers_major == 2) {
     if (vers_minor == 0) {
       parser->http.request->version = GRPC_HTTP_HTTP20;
     } else {
-      return GRPC_ERROR_CREATE(
+      return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
           "Expected one of HTTP/1.0, HTTP/1.1, or HTTP/2.0");
     }
   } else {
-    return GRPC_ERROR_CREATE("Expected one of HTTP/1.0, HTTP/1.1, or HTTP/2.0");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Expected one of HTTP/1.0, HTTP/1.1, or HTTP/2.0");
   }
 
   return GRPC_ERROR_NONE;
@@ -139,7 +159,8 @@ static grpc_error *handle_first_line(grpc_http_parser *parser) {
     case GRPC_HTTP_RESPONSE:
       return handle_response_line(parser);
   }
-  GPR_UNREACHABLE_CODE(return GRPC_ERROR_CREATE("Should never reach here"));
+  GPR_UNREACHABLE_CODE(
+      return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Should never reach here"));
 }
 
 static grpc_error *add_header(grpc_http_parser *parser) {
@@ -154,7 +175,8 @@ static grpc_error *add_header(grpc_http_parser *parser) {
   GPR_ASSERT(cur != end);
 
   if (*cur == ' ' || *cur == '\t') {
-    error = GRPC_ERROR_CREATE("Continued header lines not supported yet");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Continued header lines not supported yet");
     goto done;
   }
 
@@ -162,7 +184,8 @@ static grpc_error *add_header(grpc_http_parser *parser) {
     cur++;
   }
   if (cur == end) {
-    error = GRPC_ERROR_CREATE("Didn't find ':' in header string");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Didn't find ':' in header string");
     goto done;
   }
   GPR_ASSERT(cur >= beg);
@@ -222,7 +245,8 @@ static grpc_error *finish_line(grpc_http_parser *parser,
       }
       break;
     case GRPC_HTTP_BODY:
-      GPR_UNREACHABLE_CODE(return GRPC_ERROR_CREATE("Should never reach here"));
+      GPR_UNREACHABLE_CODE(return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+          "Should never reach here"));
   }
 
   parser->cur_line_length = 0;
@@ -240,7 +264,8 @@ static grpc_error *addbyte_body(grpc_http_parser *parser, uint8_t byte) {
     body_length = &parser->http.request->body_length;
     body = &parser->http.request->body;
   } else {
-    GPR_UNREACHABLE_CODE(return GRPC_ERROR_CREATE("Should never reach here"));
+    GPR_UNREACHABLE_CODE(
+        return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Should never reach here"));
   }
 
   if (*body_length == parser->body_capacity) {
@@ -286,7 +311,8 @@ static grpc_error *addbyte(grpc_http_parser *parser, uint8_t byte,
         if (grpc_http1_trace)
           gpr_log(GPR_ERROR, "HTTP header max line length (%d) exceeded",
                   GRPC_HTTP_PARSER_MAX_HEADER_LENGTH);
-        return GRPC_ERROR_CREATE("HTTP header max line length exceeded");
+        return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+            "HTTP header max line length exceeded");
       }
       parser->cur_line[parser->cur_line_length] = byte;
       parser->cur_line_length++;
@@ -347,7 +373,7 @@ grpc_error *grpc_http_parser_parse(grpc_http_parser *parser, grpc_slice slice,
 
 grpc_error *grpc_http_parser_eof(grpc_http_parser *parser) {
   if (parser->state != GRPC_HTTP_BODY) {
-    return GRPC_ERROR_CREATE("Did not finish headers");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Did not finish headers");
   }
   return GRPC_ERROR_NONE;
 }
diff --git a/src/core/lib/iomgr/closure.c b/src/core/lib/iomgr/closure.c
index 509c1ff95d..6633fb68ec 100644
--- a/src/core/lib/iomgr/closure.c
+++ b/src/core/lib/iomgr/closure.c
@@ -33,6 +33,7 @@
 
 #include "src/core/lib/iomgr/closure.h"
 
+#include <assert.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
@@ -124,6 +125,7 @@ void grpc_closure_run(grpc_exec_ctx *exec_ctx, grpc_closure *c,
                       grpc_error *error) {
   GPR_TIMER_BEGIN("grpc_closure_run", 0);
   if (c != NULL) {
+    assert(c->cb);
     c->scheduler->vtable->run(exec_ctx, c, error);
   } else {
     GRPC_ERROR_UNREF(error);
@@ -135,6 +137,7 @@ void grpc_closure_sched(grpc_exec_ctx *exec_ctx, grpc_closure *c,
                         grpc_error *error) {
   GPR_TIMER_BEGIN("grpc_closure_sched", 0);
   if (c != NULL) {
+    assert(c->cb);
     c->scheduler->vtable->sched(exec_ctx, c, error);
   } else {
     GRPC_ERROR_UNREF(error);
@@ -146,6 +149,7 @@ void grpc_closure_list_sched(grpc_exec_ctx *exec_ctx, grpc_closure_list *list) {
   grpc_closure *c = list->head;
   while (c != NULL) {
     grpc_closure *next = c->next_data.next;
+    assert(c->cb);
     c->scheduler->vtable->sched(exec_ctx, c, c->error_data.error);
     c = next;
   }
diff --git a/src/core/lib/iomgr/combiner.c b/src/core/lib/iomgr/combiner.c
index fa9966c3a6..2bc476bbef 100644
--- a/src/core/lib/iomgr/combiner.c
+++ b/src/core/lib/iomgr/combiner.c
@@ -33,6 +33,7 @@
 
 #include "src/core/lib/iomgr/combiner.h"
 
+#include <assert.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
@@ -216,6 +217,7 @@ static void combiner_exec(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
       GPR_DEBUG, "C:%p grpc_combiner_execute c=%p cov=%d last=%" PRIdPTR, lock,
       cl, covered_by_poller, last));
   GPR_ASSERT(last & STATE_UNORPHANED);  // ensure lock has not been destroyed
+  assert(cl->cb);
   cl->error_data.scratch =
       pack_error_data((error_data){error, covered_by_poller});
   if (covered_by_poller) {
diff --git a/src/core/lib/iomgr/error.c b/src/core/lib/iomgr/error.c
index 1127fff756..1dbb64e8f3 100644
--- a/src/core/lib/iomgr/error.c
+++ b/src/core/lib/iomgr/error.c
@@ -35,7 +35,6 @@
 
 #include <string.h>
 
-#include <grpc/slice.h>
 #include <grpc/status.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
@@ -287,7 +286,7 @@ static void internal_add_error(grpc_error **err, grpc_error *new) {
 // It is very common to include and extra int and string in an error
 #define SURPLUS_CAPACITY (2 * SLOTS_PER_INT + SLOTS_PER_TIME)
 
-grpc_error *grpc_error_create(const char *file, int line, const char *desc,
+grpc_error *grpc_error_create(grpc_slice file, int line, grpc_slice desc,
                               grpc_error **referencing,
                               size_t num_referencing) {
   GPR_TIMER_BEGIN("grpc_error_create", 0);
@@ -313,14 +312,8 @@ grpc_error *grpc_error_create(const char *file, int line, const char *desc,
   memset(err->times, UINT8_MAX, GRPC_ERROR_TIME_MAX);
 
   internal_set_int(&err, GRPC_ERROR_INT_FILE_LINE, line);
-  internal_set_str(&err, GRPC_ERROR_STR_FILE,
-                   grpc_slice_from_static_string(file));
-  internal_set_str(
-      &err, GRPC_ERROR_STR_DESCRIPTION,
-      grpc_slice_from_copied_buffer(
-          desc,
-          strlen(desc) +
-              1));  // TODO, pull this up.  // TODO(ncteisen), pull this up.
+  internal_set_str(&err, GRPC_ERROR_STR_FILE, file);
+  internal_set_str(&err, GRPC_ERROR_STR_DESCRIPTION, desc);
 
   for (size_t i = 0; i < num_referencing; ++i) {
     if (referencing[i] == GRPC_ERROR_NONE) continue;
@@ -360,7 +353,7 @@ static grpc_error *copy_error_and_unref(grpc_error *in) {
   GPR_TIMER_BEGIN("copy_error_and_unref", 0);
   grpc_error *out;
   if (grpc_error_is_special(in)) {
-    out = GRPC_ERROR_CREATE("unknown");
+    out = GRPC_ERROR_CREATE_FROM_STATIC_STRING("unknown");
     if (in == GRPC_ERROR_NONE) {
       internal_set_str(&out, GRPC_ERROR_STR_DESCRIPTION,
                        grpc_slice_from_static_string("no error"));
@@ -417,7 +410,7 @@ typedef struct {
   const char *msg;
 } special_error_status_map;
 static special_error_status_map error_status_map[] = {
-    {GRPC_ERROR_NONE, GRPC_STATUS_OK, NULL},
+    {GRPC_ERROR_NONE, GRPC_STATUS_OK, ""},
     {GRPC_ERROR_CANCELLED, GRPC_STATUS_CANCELLED, "Cancelled"},
     {GRPC_ERROR_OOM, GRPC_STATUS_RESOURCE_EXHAUSTED, "Out of memory"},
 };
@@ -448,33 +441,33 @@ bool grpc_error_get_int(grpc_error *err, grpc_error_ints which, intptr_t *p) {
 }
 
 grpc_error *grpc_error_set_str(grpc_error *src, grpc_error_strs which,
-                               const char *value) {
+                               grpc_slice str) {
   GPR_TIMER_BEGIN("grpc_error_set_str", 0);
   grpc_error *new = copy_error_and_unref(src);
-  internal_set_str(&new, which,
-                   grpc_slice_from_copied_buffer(
-                       value, strlen(value) + 1));  // TODO, pull this up.
+  internal_set_str(&new, which, str);
   GPR_TIMER_END("grpc_error_set_str", 0);
   return new;
 }
 
-const char *grpc_error_get_str(grpc_error *err, grpc_error_strs which) {
+bool grpc_error_get_str(grpc_error *err, grpc_error_strs which,
+                        grpc_slice *str) {
   if (grpc_error_is_special(err)) {
     if (which == GRPC_ERROR_STR_GRPC_MESSAGE) {
       for (size_t i = 0; i < GPR_ARRAY_SIZE(error_status_map); i++) {
         if (error_status_map[i].error == err) {
-          return error_status_map[i].msg;
+          *str = grpc_slice_from_static_string(error_status_map[i].msg);
+          return true;
         }
       }
     }
-    return NULL;
+    return false;
   }
   uint8_t slot = err->strs[which];
   if (slot != UINT8_MAX) {
-    return (const char *)GRPC_SLICE_START_PTR(
-        *(grpc_slice *)(err->arena + slot));
+    *str = *(grpc_slice *)(err->arena + slot);
+    return true;
   } else {
-    return NULL;
+    return false;
   }
 }
 
@@ -515,13 +508,14 @@ static void append_str(const char *str, char **s, size_t *sz, size_t *cap) {
   }
 }
 
-static void append_esc_str(const char *str, char **s, size_t *sz, size_t *cap) {
+static void append_esc_str(const uint8_t *str, size_t len, char **s, size_t *sz,
+                           size_t *cap) {
   static const char *hex = "0123456789abcdef";
   append_chr('"', s, sz, cap);
-  for (const uint8_t *c = (const uint8_t *)str; *c; c++) {
-    if (*c < 32 || *c >= 127) {
+  for (size_t i = 0; i < len; i++, str++) {
+    if (*str < 32 || *str >= 127) {
       append_chr('\\', s, sz, cap);
-      switch (*c) {
+      switch (*str) {
         case '\b':
           append_chr('b', s, sz, cap);
           break;
@@ -541,12 +535,12 @@ static void append_esc_str(const char *str, char **s, size_t *sz, size_t *cap) {
           append_chr('u', s, sz, cap);
           append_chr('0', s, sz, cap);
           append_chr('0', s, sz, cap);
-          append_chr(hex[*c >> 4], s, sz, cap);
-          append_chr(hex[*c & 0x0f], s, sz, cap);
+          append_chr(hex[*str >> 4], s, sz, cap);
+          append_chr(hex[*str & 0x0f], s, sz, cap);
           break;
       }
     } else {
-      append_chr((char)*c, s, sz, cap);
+      append_chr((char)*str, s, sz, cap);
     }
   }
   append_chr('"', s, sz, cap);
@@ -586,11 +580,12 @@ static char *key_str(grpc_error_strs which) {
   return gpr_strdup(error_str_name(which));
 }
 
-static char *fmt_str(void *p) {
+static char *fmt_str(grpc_slice slice) {
   char *s = NULL;
   size_t sz = 0;
   size_t cap = 0;
-  append_esc_str(p, &s, &sz, &cap);
+  append_esc_str((const uint8_t *)GRPC_SLICE_START_PTR(slice),
+                 GRPC_SLICE_LENGTH(slice), &s, &sz, &cap);
   append_chr(0, &s, &sz, &cap);
   return s;
 }
@@ -599,9 +594,8 @@ static void collect_strs_kvs(grpc_error *err, kv_pairs *kvs) {
   for (size_t which = 0; which < GRPC_ERROR_STR_MAX; ++which) {
     uint8_t slot = err->strs[which];
     if (slot != UINT8_MAX) {
-      append_kv(
-          kvs, key_str((grpc_error_strs)which),
-          fmt_str(GRPC_SLICE_START_PTR(*(grpc_slice *)(err->arena + slot))));
+      append_kv(kvs, key_str((grpc_error_strs)which),
+                fmt_str(*(grpc_slice *)(err->arena + slot)));
     }
   }
 }
@@ -681,7 +675,8 @@ static char *finish_kvs(kv_pairs *kvs) {
   append_chr('{', &s, &sz, &cap);
   for (size_t i = 0; i < kvs->num_kvs; i++) {
     if (i != 0) append_chr(',', &s, &sz, &cap);
-    append_esc_str(kvs->kvs[i].key, &s, &sz, &cap);
+    append_esc_str((const uint8_t *)kvs->kvs[i].key, strlen(kvs->kvs[i].key),
+                   &s, &sz, &cap);
     gpr_free(kvs->kvs[i].key);
     append_chr(':', &s, &sz, &cap);
     append_str(kvs->kvs[i].value, &s, &sz, &cap);
@@ -733,10 +728,14 @@ grpc_error *grpc_os_error(const char *file, int line, int err,
                           const char *call_name) {
   return grpc_error_set_str(
       grpc_error_set_str(
-          grpc_error_set_int(grpc_error_create(file, line, "OS Error", NULL, 0),
-                             GRPC_ERROR_INT_ERRNO, err),
-          GRPC_ERROR_STR_OS_ERROR, strerror(err)),
-      GRPC_ERROR_STR_SYSCALL, call_name);
+          grpc_error_set_int(
+              grpc_error_create(grpc_slice_from_static_string(file), line,
+                                grpc_slice_from_static_string("OS Error"), NULL,
+                                0),
+              GRPC_ERROR_INT_ERRNO, err),
+          GRPC_ERROR_STR_OS_ERROR,
+          grpc_slice_from_static_string(strerror(err))),
+      GRPC_ERROR_STR_SYSCALL, grpc_slice_from_static_string(call_name));
 }
 
 #ifdef GPR_WINDOWS
@@ -745,10 +744,13 @@ grpc_error *grpc_wsa_error(const char *file, int line, int err,
   char *utf8_message = gpr_format_message(err);
   grpc_error *error = grpc_error_set_str(
       grpc_error_set_str(
-          grpc_error_set_int(grpc_error_create(file, line, "OS Error", NULL, 0),
-                             GRPC_ERROR_INT_WSA_ERROR, err),
-          GRPC_ERROR_STR_OS_ERROR, utf8_message),
-      GRPC_ERROR_STR_SYSCALL, call_name);
+          grpc_error_set_int(
+              grpc_error_create(grpc_slice_from_static_string(file), line,
+                                grpc_slice_from_static_string("OS Error"), NULL,
+                                0),
+              GRPC_ERROR_INT_WSA_ERROR, err),
+          GRPC_ERROR_STR_OS_ERROR, grpc_slice_from_copied_string(utf8_message)),
+      GRPC_ERROR_STR_SYSCALL, grpc_slice_from_static_string(call_name));
   gpr_free(utf8_message);
   return error;
 }
diff --git a/src/core/lib/iomgr/error.h b/src/core/lib/iomgr/error.h
index eb953947ae..2a44fcfe25 100644
--- a/src/core/lib/iomgr/error.h
+++ b/src/core/lib/iomgr/error.h
@@ -37,6 +37,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#include <grpc/slice.h>
 #include <grpc/status.h>
 #include <grpc/support/time.h>
 
@@ -45,28 +46,9 @@ extern "C" {
 #endif
 
 /// Opaque representation of an error.
-/// Errors are refcounted objects that represent the result of an operation.
-/// Ownership laws:
-///  if a grpc_error is returned by a function, the caller owns a ref to that
-///    instance
-///  if a grpc_error is passed to a grpc_closure callback function (functions
-///    with the signature:
-///      void (*f)(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error))
-///    then those functions do not own a ref to error (but are free to manually
-///    take a reference).
-///  if a grpc_error is passed to *ANY OTHER FUNCTION* then that function takes
-///    ownership of the error
-/// Errors have:
-///  a set of ints, strings, and timestamps that describe the error
-///  always present are:
-///    GRPC_ERROR_STR_FILE, GRPC_ERROR_INT_FILE_LINE - source location the error
-///      was generated
-///    GRPC_ERROR_STR_DESCRIPTION - a human readable description of the error
-///    GRPC_ERROR_TIME_CREATED - a timestamp indicating when the error happened
-///  an error can also have children; these are other errors that are believed
-///    to have contributed to this one. By accumulating children, we can begin
-///    to root cause high level failures from low level failures, without having
-///    to derive execution paths from log lines
+/// See https://github.com/grpc/grpc/blob/master/doc/core/grpc-error.md for a
+/// full write up of this object.
+
 typedef struct grpc_error grpc_error;
 
 typedef enum {
@@ -156,7 +138,7 @@ typedef enum {
 const char *grpc_error_string(grpc_error *error);
 
 /// Create an error - but use GRPC_ERROR_CREATE instead
-grpc_error *grpc_error_create(const char *file, int line, const char *desc,
+grpc_error *grpc_error_create(grpc_slice file, int line, grpc_slice desc,
                               grpc_error **referencing, size_t num_referencing);
 /// Create an error (this is the preferred way of generating an error that is
 ///   not due to a system call - for system calls, use GRPC_OS_ERROR or
@@ -166,13 +148,21 @@ grpc_error *grpc_error_create(const char *file, int line, const char *desc,
 /// err = grpc_error_create(x, y, z, r, nr) is equivalent to:
 ///   err = grpc_error_create(x, y, z, NULL, 0);
 ///   for (i=0; i<nr; i++) err = grpc_error_add_child(err, r[i]);
-#define GRPC_ERROR_CREATE(desc) \
-  grpc_error_create(__FILE__, __LINE__, desc, NULL, 0)
+#define GRPC_ERROR_CREATE_FROM_STATIC_STRING(desc)                     \
+  grpc_error_create(grpc_slice_from_static_string(__FILE__), __LINE__, \
+                    grpc_slice_from_static_string(desc), NULL, 0)
+#define GRPC_ERROR_CREATE_FROM_COPIED_STRING(desc)                     \
+  grpc_error_create(grpc_slice_from_static_string(__FILE__), __LINE__, \
+                    grpc_slice_from_copied_string(desc), NULL, 0)
 
 // Create an error that references some other errors. This function adds a
 // reference to each error in errs - it does not consume an existing reference
-#define GRPC_ERROR_CREATE_REFERENCING(desc, errs, count) \
-  grpc_error_create(__FILE__, __LINE__, desc, errs, count)
+#define GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(desc, errs, count) \
+  grpc_error_create(grpc_slice_from_static_string(__FILE__), __LINE__,      \
+                    grpc_slice_from_static_string(desc), errs, count)
+#define GRPC_ERROR_CREATE_REFERENCING_FROM_COPIED_STRING(desc, errs, count) \
+  grpc_error_create(grpc_slice_from_static_string(__FILE__), __LINE__,      \
+                    grpc_slice_from_copied_string(desc), errs, count)
 
 //#define GRPC_ERROR_REFCOUNT_DEBUG
 #ifdef GRPC_ERROR_REFCOUNT_DEBUG
@@ -194,10 +184,11 @@ grpc_error *grpc_error_set_int(grpc_error *src, grpc_error_ints which,
                                intptr_t value) GRPC_MUST_USE_RESULT;
 bool grpc_error_get_int(grpc_error *error, grpc_error_ints which, intptr_t *p);
 grpc_error *grpc_error_set_str(grpc_error *src, grpc_error_strs which,
-                               const char *value) GRPC_MUST_USE_RESULT;
-/// Returns NULL if the specified string is not set.
-/// Caller does NOT own return value.
-const char *grpc_error_get_str(grpc_error *error, grpc_error_strs which);
+                               grpc_slice str) GRPC_MUST_USE_RESULT;
+/// Returns false if the specified string is not set.
+/// Caller does NOT own the slice.
+bool grpc_error_get_str(grpc_error *error, grpc_error_strs which,
+                        grpc_slice *s);
 
 /// Add a child error: an error that is believed to have contributed to this
 /// error occurring. Allows root causing high level errors from lower level
diff --git a/src/core/lib/iomgr/ev_epoll_linux.c b/src/core/lib/iomgr/ev_epoll_linux.c
index d5acdf0d4b..c4c67df381 100644
--- a/src/core/lib/iomgr/ev_epoll_linux.c
+++ b/src/core/lib/iomgr/ev_epoll_linux.c
@@ -321,7 +321,7 @@ static bool append_error(grpc_error **composite, grpc_error *error,
                          const char *desc) {
   if (error == GRPC_ERROR_NONE) return true;
   if (*composite == GRPC_ERROR_NONE) {
-    *composite = GRPC_ERROR_CREATE(desc);
+    *composite = GRPC_ERROR_CREATE_FROM_COPIED_STRING(desc);
   }
   *composite = grpc_error_add_child(*composite, error);
   return false;
@@ -1110,7 +1110,13 @@ static void notify_on(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state,
     gpr_atm curr = gpr_atm_no_barrier_load(state);
     switch (curr) {
       case CLOSURE_NOT_READY: {
-        /* CLOSURE_NOT_READY -> <closure>. */
+        /* CLOSURE_NOT_READY -> <closure>.
+
+           We're guaranteed by API that there's an acquire barrier before here,
+           so there's no need to double-dip and this can be a release-only.
+
+           The release itself pairs with the acquire half of a set_ready full
+           barrier. */
         if (gpr_atm_rel_cas(state, CLOSURE_NOT_READY, (gpr_atm)closure)) {
           return; /* Successful. Return */
         }
@@ -1141,9 +1147,9 @@ static void notify_on(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state,
            schedule the closure with the shutdown error */
         if ((curr & FD_SHUTDOWN_BIT) > 0) {
           grpc_error *shutdown_err = (grpc_error *)(curr & ~FD_SHUTDOWN_BIT);
-          grpc_closure_sched(
-              exec_ctx, closure,
-              GRPC_ERROR_CREATE_REFERENCING("FD Shutdown", &shutdown_err, 1));
+          grpc_closure_sched(exec_ctx, closure,
+                             GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                                 "FD Shutdown", &shutdown_err, 1));
           return;
         }
 
@@ -1169,7 +1175,9 @@ static void set_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state,
     switch (curr) {
       case CLOSURE_READY:
       case CLOSURE_NOT_READY:
-        if (gpr_atm_full_cas(state, curr, new_state)) {
+        /* Release cas to pair with a set_ready performing a load of the
+           shutdown state later */
+        if (gpr_atm_rel_cas(state, curr, new_state)) {
           return; /* early out */
         }
         break; /* retry */
@@ -1183,11 +1191,14 @@ static void set_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state,
         }
 
         /* Fd is not shutdown. Schedule the closure and move the state to
-           shutdown state. */
+           shutdown state.
+           Needs an acquire to pair with setting the closure (and get a
+           happens-after on that edge), and a release to pair with anything
+           loading the shutdown state. */
         if (gpr_atm_full_cas(state, curr, new_state)) {
-          grpc_closure_sched(
-              exec_ctx, (grpc_closure *)curr,
-              GRPC_ERROR_CREATE_REFERENCING("FD Shutdown", &shutdown_err, 1));
+          grpc_closure_sched(exec_ctx, (grpc_closure *)curr,
+                             GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                                 "FD Shutdown", &shutdown_err, 1));
           return;
         }
 
@@ -1212,6 +1223,8 @@ static void set_ready(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state) {
       }
 
       case CLOSURE_NOT_READY: {
+        /* No barrier required as we're transitioning to a state that does not
+           involve a closure */
         if (gpr_atm_no_barrier_cas(state, CLOSURE_NOT_READY, CLOSURE_READY)) {
           return; /* early out */
         }
@@ -1223,7 +1236,11 @@ static void set_ready(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state) {
         if ((curr & FD_SHUTDOWN_BIT) > 0) {
           /* The fd is shutdown. Do nothing */
           return;
-        } else if (gpr_atm_full_cas(state, curr, CLOSURE_NOT_READY)) {
+        }
+        /* Full cas: acquire pairs with this cas' release in the event of a
+           spurious set_ready; release pairs with this or the acquire in
+           notify_on (or set_shutdown) */
+        else if (gpr_atm_full_cas(state, curr, CLOSURE_NOT_READY)) {
           grpc_closure_sched(exec_ctx, (grpc_closure *)curr, GRPC_ERROR_NONE);
           return;
         }
diff --git a/src/core/lib/iomgr/ev_poll_posix.c b/src/core/lib/iomgr/ev_poll_posix.c
index 5ddd5313e2..ca6e855611 100644
--- a/src/core/lib/iomgr/ev_poll_posix.c
+++ b/src/core/lib/iomgr/ev_poll_posix.c
@@ -451,14 +451,16 @@ static grpc_error *fd_shutdown_error(grpc_fd *fd) {
   if (!fd->shutdown) {
     return GRPC_ERROR_NONE;
   } else {
-    return GRPC_ERROR_CREATE_REFERENCING("FD shutdown", &fd->shutdown_error, 1);
+    return GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+        "FD shutdown", &fd->shutdown_error, 1);
   }
 }
 
 static void notify_on_locked(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
                              grpc_closure **st, grpc_closure *closure) {
   if (fd->shutdown) {
-    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_CREATE("FD shutdown"));
+    grpc_closure_sched(exec_ctx, closure,
+                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("FD shutdown"));
   } else if (*st == CLOSURE_NOT_READY) {
     /* not ready ==> switch to a waiting state by setting the closure */
     *st = closure;
@@ -696,7 +698,7 @@ static void push_front_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
 static void kick_append_error(grpc_error **composite, grpc_error *error) {
   if (error == GRPC_ERROR_NONE) return;
   if (*composite == GRPC_ERROR_NONE) {
-    *composite = GRPC_ERROR_CREATE("Kick Failure");
+    *composite = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Kick Failure");
   }
   *composite = grpc_error_add_child(*composite, error);
 }
@@ -859,7 +861,7 @@ static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset) {
 static void work_combine_error(grpc_error **composite, grpc_error *error) {
   if (error == GRPC_ERROR_NONE) return;
   if (*composite == GRPC_ERROR_NONE) {
-    *composite = GRPC_ERROR_CREATE("pollset_work");
+    *composite = GRPC_ERROR_CREATE_FROM_STATIC_STRING("pollset_work");
   }
   *composite = grpc_error_add_child(*composite, error);
 }
@@ -1421,7 +1423,7 @@ static int cvfd_poll(struct pollfd *fds, nfds_t nfds, int timeout) {
     g_cvfds.pollcount++;
     opt = gpr_thd_options_default();
     gpr_thd_options_set_detached(&opt);
-    gpr_thd_new(&t_id, &run_poll, pargs, &opt);
+    GPR_ASSERT(gpr_thd_new(&t_id, &run_poll, pargs, &opt));
     // We want the poll() thread to trigger the deadline, so wait forever here
     gpr_cv_wait(pollcv, &g_cvfds.mu, gpr_inf_future(GPR_CLOCK_MONOTONIC));
     if (gpr_atm_no_barrier_load(&pargs->status) == COMPLETED) {
diff --git a/src/core/lib/iomgr/executor.c b/src/core/lib/iomgr/executor.c
index a5b62aa888..ae3e2eabc3 100644
--- a/src/core/lib/iomgr/executor.c
+++ b/src/core/lib/iomgr/executor.c
@@ -115,8 +115,8 @@ static void maybe_spawn_locked() {
   /* All previous instances of the thread should have been joined at this point.
    * Spawn time! */
   g_executor.busy = 1;
-  gpr_thd_new(&g_executor.tid, closure_exec_thread_func, NULL,
-              &g_executor.options);
+  GPR_ASSERT(gpr_thd_new(&g_executor.tid, closure_exec_thread_func, NULL,
+                         &g_executor.options));
   g_executor.pending_join = 1;
 }
 
diff --git a/src/core/lib/iomgr/load_file.c b/src/core/lib/iomgr/load_file.c
index f40c8b28cc..208f74e20c 100644
--- a/src/core/lib/iomgr/load_file.c
+++ b/src/core/lib/iomgr/load_file.c
@@ -78,9 +78,12 @@ end:
   *output = result;
   if (file != NULL) fclose(file);
   if (error != GRPC_ERROR_NONE) {
-    grpc_error *error_out = grpc_error_set_str(
-        GRPC_ERROR_CREATE_REFERENCING("Failed to load file", &error, 1),
-        GRPC_ERROR_STR_FILENAME, filename);
+    grpc_error *error_out =
+        grpc_error_set_str(GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                               "Failed to load file", &error, 1),
+                           GRPC_ERROR_STR_FILENAME,
+                           grpc_slice_from_copied_string(
+                               filename));  // TODO(ncteisen), always static?
     GRPC_ERROR_UNREF(error);
     error = error_out;
   }
diff --git a/src/core/lib/iomgr/port.h b/src/core/lib/iomgr/port.h
index f1897bb91f..94a454c0b7 100644
--- a/src/core/lib/iomgr/port.h
+++ b/src/core/lib/iomgr/port.h
@@ -39,6 +39,7 @@
 #if defined(GRPC_UV)
 // Do nothing
 #elif defined(GPR_MANYLINUX1)
+#define GRPC_HAVE_IFADDRS 1
 #define GRPC_HAVE_IPV6_RECVPKTINFO 1
 #define GRPC_HAVE_IP_PKTINFO 1
 #define GRPC_HAVE_MSG_NOSIGNAL 1
@@ -65,6 +66,7 @@
 #define GRPC_POSIX_WAKEUP_FD 1
 #define GRPC_TIMER_USE_GENERIC 1
 #elif defined(GPR_LINUX)
+#define GRPC_HAVE_IFADDRS 1
 #define GRPC_HAVE_IPV6_RECVPKTINFO 1
 #define GRPC_HAVE_IP_PKTINFO 1
 #define GRPC_HAVE_MSG_NOSIGNAL 1
@@ -90,6 +92,7 @@
 #define GRPC_POSIX_SOCKETUTILS
 #endif
 #elif defined(GPR_APPLE)
+#define GRPC_HAVE_IFADDRS 1
 #define GRPC_HAVE_SO_NOSIGPIPE 1
 #define GRPC_HAVE_UNIX_SOCKET 1
 #define GRPC_MSG_IOVLEN_TYPE int
@@ -100,6 +103,7 @@
 #define GRPC_POSIX_WAKEUP_FD 1
 #define GRPC_TIMER_USE_GENERIC 1
 #elif defined(GPR_FREEBSD)
+#define GRPC_HAVE_IFADDRS 1
 #define GRPC_HAVE_IPV6_RECVPKTINFO 1
 #define GRPC_HAVE_SO_NOSIGPIPE 1
 #define GRPC_HAVE_UNIX_SOCKET 1
diff --git a/src/core/lib/iomgr/resolve_address_posix.c b/src/core/lib/iomgr/resolve_address_posix.c
index 50e470d149..d0ede0f2d5 100644
--- a/src/core/lib/iomgr/resolve_address_posix.c
+++ b/src/core/lib/iomgr/resolve_address_posix.c
@@ -73,14 +73,16 @@ static grpc_error *blocking_resolve_address_impl(
   /* parse name, splitting it into host and port parts */
   gpr_split_host_port(name, &host, &port);
   if (host == NULL) {
-    err = grpc_error_set_str(GRPC_ERROR_CREATE("unparseable host:port"),
-                             GRPC_ERROR_STR_TARGET_ADDRESS, name);
+    err = grpc_error_set_str(
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("unparseable host:port"),
+        GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name));
     goto done;
   }
   if (port == NULL) {
     if (default_port == NULL) {
-      err = grpc_error_set_str(GRPC_ERROR_CREATE("no port in name"),
-                               GRPC_ERROR_STR_TARGET_ADDRESS, name);
+      err = grpc_error_set_str(
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("no port in name"),
+          GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name));
       goto done;
     }
     port = gpr_strdup(default_port);
@@ -112,11 +114,15 @@ static grpc_error *blocking_resolve_address_impl(
   if (s != 0) {
     err = grpc_error_set_str(
         grpc_error_set_str(
-            grpc_error_set_str(grpc_error_set_int(GRPC_ERROR_CREATE("OS Error"),
-                                                  GRPC_ERROR_INT_ERRNO, s),
-                               GRPC_ERROR_STR_OS_ERROR, gai_strerror(s)),
-            GRPC_ERROR_STR_SYSCALL, "getaddrinfo"),
-        GRPC_ERROR_STR_TARGET_ADDRESS, name);
+            grpc_error_set_str(
+                grpc_error_set_int(
+                    GRPC_ERROR_CREATE_FROM_STATIC_STRING("OS Error"),
+                    GRPC_ERROR_INT_ERRNO, s),
+                GRPC_ERROR_STR_OS_ERROR,
+                grpc_slice_from_static_string(gai_strerror(s))),
+            GRPC_ERROR_STR_SYSCALL,
+            grpc_slice_from_static_string("getaddrinfo")),
+        GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name));
     goto done;
   }
 
diff --git a/src/core/lib/iomgr/resolve_address_uv.c b/src/core/lib/iomgr/resolve_address_uv.c
index 4d715be94c..102d1aa290 100644
--- a/src/core/lib/iomgr/resolve_address_uv.c
+++ b/src/core/lib/iomgr/resolve_address_uv.c
@@ -92,9 +92,10 @@ static grpc_error *handle_addrinfo_result(int status, struct addrinfo *result,
   if (status != 0) {
     grpc_error *error;
     *addresses = NULL;
-    error = GRPC_ERROR_CREATE("getaddrinfo failed");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("getaddrinfo failed");
     error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, uv_strerror(status));
+        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                           grpc_slice_from_static_string(uv_strerror(status)));
     return error;
   }
   (*addresses) = gpr_malloc(sizeof(grpc_resolved_addresses));
@@ -153,7 +154,7 @@ static grpc_error *try_split_host_port(const char *name,
   if (*host == NULL) {
     char *msg;
     gpr_asprintf(&msg, "unparseable host:port: '%s'", name);
-    error = GRPC_ERROR_CREATE(msg);
+    error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
     gpr_free(msg);
     return error;
   }
@@ -162,7 +163,7 @@ static grpc_error *try_split_host_port(const char *name,
     if (default_port == NULL) {
       char *msg;
       gpr_asprintf(&msg, "no port in name '%s'", name);
-      error = GRPC_ERROR_CREATE(msg);
+      error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
       gpr_free(msg);
       return error;
     }
@@ -262,8 +263,9 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
 
   if (s != 0) {
     *addrs = NULL;
-    err = GRPC_ERROR_CREATE("getaddrinfo failed");
-    err = grpc_error_set_str(err, GRPC_ERROR_STR_OS_ERROR, uv_strerror(s));
+    err = GRPC_ERROR_CREATE_FROM_STATIC_STRING("getaddrinfo failed");
+    err = grpc_error_set_str(err, GRPC_ERROR_STR_OS_ERROR,
+                             grpc_slice_from_static_string(uv_strerror(s)));
     grpc_closure_sched(exec_ctx, on_done, err);
     gpr_free(r);
     gpr_free(req);
diff --git a/src/core/lib/iomgr/resolve_address_windows.c b/src/core/lib/iomgr/resolve_address_windows.c
index 2439ce3cb7..22eca1fd3b 100644
--- a/src/core/lib/iomgr/resolve_address_windows.c
+++ b/src/core/lib/iomgr/resolve_address_windows.c
@@ -78,7 +78,7 @@ static grpc_error *blocking_resolve_address_impl(
   if (host == NULL) {
     char *msg;
     gpr_asprintf(&msg, "unparseable host:port: '%s'", name);
-    error = GRPC_ERROR_CREATE(msg);
+    error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
     gpr_free(msg);
     goto done;
   }
@@ -86,7 +86,7 @@ static grpc_error *blocking_resolve_address_impl(
     if (default_port == NULL) {
       char *msg;
       gpr_asprintf(&msg, "no port in name '%s'", name);
-      error = GRPC_ERROR_CREATE(msg);
+      error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
       gpr_free(msg);
       goto done;
     }
diff --git a/src/core/lib/iomgr/resource_quota.c b/src/core/lib/iomgr/resource_quota.c
index 511ffdcdf1..8dcd80d001 100644
--- a/src/core/lib/iomgr/resource_quota.c
+++ b/src/core/lib/iomgr/resource_quota.c
@@ -279,11 +279,17 @@ static void rq_step_sched(grpc_exec_ctx *exec_ctx,
 /* update the atomically available resource estimate - use no barriers since
    timeliness of delivery really doesn't matter much */
 static void rq_update_estimate(grpc_resource_quota *resource_quota) {
+  gpr_atm memory_usage_estimation = MEMORY_USAGE_ESTIMATION_MAX;
+  if (resource_quota->size != 0) {
+    memory_usage_estimation =
+        GPR_CLAMP((gpr_atm)((1.0 -
+                             ((double)resource_quota->free_pool) /
+                                 ((double)resource_quota->size)) *
+                            MEMORY_USAGE_ESTIMATION_MAX),
+                  0, MEMORY_USAGE_ESTIMATION_MAX);
+  }
   gpr_atm_no_barrier_store(&resource_quota->memory_usage_estimation,
-                           (gpr_atm)((1.0 -
-                                      ((double)resource_quota->free_pool) /
-                                          ((double)resource_quota->size)) *
-                                     MEMORY_USAGE_ESTIMATION_MAX));
+                           memory_usage_estimation);
 }
 
 /* returns true if all allocations are completed */
diff --git a/src/core/lib/iomgr/socket_factory_posix.c b/src/core/lib/iomgr/socket_factory_posix.c
new file mode 100644
index 0000000000..1050a14c46
--- /dev/null
+++ b/src/core/lib/iomgr/socket_factory_posix.c
@@ -0,0 +1,110 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_POSIX_SOCKET
+
+#include "src/core/lib/iomgr/socket_factory_posix.h"
+
+#include <grpc/impl/codegen/grpc_types.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/useful.h>
+
+void grpc_socket_factory_init(grpc_socket_factory *factory,
+                              const grpc_socket_factory_vtable *vtable) {
+  factory->vtable = vtable;
+  gpr_ref_init(&factory->refcount, 1);
+}
+
+int grpc_socket_factory_socket(grpc_socket_factory *factory, int domain,
+                               int type, int protocol) {
+  return factory->vtable->socket(factory, domain, type, protocol);
+}
+
+int grpc_socket_factory_bind(grpc_socket_factory *factory, int sockfd,
+                             const grpc_resolved_address *addr) {
+  return factory->vtable->bind(factory, sockfd, addr);
+}
+
+int grpc_socket_factory_compare(grpc_socket_factory *a,
+                                grpc_socket_factory *b) {
+  int c = GPR_ICMP(a, b);
+  if (c != 0) {
+    grpc_socket_factory *sma = a;
+    grpc_socket_factory *smb = b;
+    c = GPR_ICMP(sma->vtable, smb->vtable);
+    if (c == 0) {
+      c = sma->vtable->compare(sma, smb);
+    }
+  }
+  return c;
+}
+
+grpc_socket_factory *grpc_socket_factory_ref(grpc_socket_factory *factory) {
+  gpr_ref(&factory->refcount);
+  return factory;
+}
+
+void grpc_socket_factory_unref(grpc_socket_factory *factory) {
+  if (gpr_unref(&factory->refcount)) {
+    factory->vtable->destroy(factory);
+  }
+}
+
+static void *socket_factory_arg_copy(void *p) {
+  return grpc_socket_factory_ref(p);
+}
+
+static void socket_factory_arg_destroy(grpc_exec_ctx *exec_ctx, void *p) {
+  grpc_socket_factory_unref(p);
+}
+
+static int socket_factory_cmp(void *a, void *b) {
+  return grpc_socket_factory_compare((grpc_socket_factory *)a,
+                                     (grpc_socket_factory *)b);
+}
+
+static const grpc_arg_pointer_vtable socket_factory_arg_vtable = {
+    socket_factory_arg_copy, socket_factory_arg_destroy, socket_factory_cmp};
+
+grpc_arg grpc_socket_factory_to_arg(grpc_socket_factory *factory) {
+  grpc_arg arg;
+  arg.type = GRPC_ARG_POINTER;
+  arg.key = GRPC_ARG_SOCKET_FACTORY;
+  arg.value.pointer.vtable = &socket_factory_arg_vtable;
+  arg.value.pointer.p = factory;
+  return arg;
+}
+
+#endif
diff --git a/src/core/lib/iomgr/socket_factory_posix.h b/src/core/lib/iomgr/socket_factory_posix.h
new file mode 100644
index 0000000000..2c63299030
--- /dev/null
+++ b/src/core/lib/iomgr/socket_factory_posix.h
@@ -0,0 +1,90 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_IOMGR_SOCKET_FACTORY_POSIX_H
+#define GRPC_CORE_LIB_IOMGR_SOCKET_FACTORY_POSIX_H
+
+#include <grpc/impl/codegen/grpc_types.h>
+#include <grpc/support/sync.h>
+#include "src/core/lib/iomgr/resolve_address.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** The virtual table of grpc_socket_factory */
+typedef struct {
+  /** Replacement for socket(2) */
+  int (*socket)(grpc_socket_factory *factory, int domain, int type,
+                int protocol);
+  /** Replacement for bind(2) */
+  int (*bind)(grpc_socket_factory *factory, int sockfd,
+              const grpc_resolved_address *addr);
+  /** Compare socket factory \a a and \a b */
+  int (*compare)(grpc_socket_factory *a, grpc_socket_factory *b);
+  /** Destroys the socket factory instance */
+  void (*destroy)(grpc_socket_factory *factory);
+} grpc_socket_factory_vtable;
+
+/** The Socket Factory interface allows changes on socket options */
+struct grpc_socket_factory {
+  const grpc_socket_factory_vtable *vtable;
+  gpr_refcount refcount;
+};
+
+/** called by concrete implementations to initialize the base struct */
+void grpc_socket_factory_init(grpc_socket_factory *factory,
+                              const grpc_socket_factory_vtable *vtable);
+
+/** Wrap \a factory as a grpc_arg */
+grpc_arg grpc_socket_factory_to_arg(grpc_socket_factory *factory);
+
+/** Perform the equivalent of a socket(2) operation using \a factory */
+int grpc_socket_factory_socket(grpc_socket_factory *factory, int domain,
+                               int type, int protocol);
+
+/** Perform the equivalent of a bind(2) operation using \a factory */
+int grpc_socket_factory_bind(grpc_socket_factory *factory, int sockfd,
+                             const grpc_resolved_address *addr);
+
+/** Compare if \a a and \a b are the same factory or have same settings */
+int grpc_socket_factory_compare(grpc_socket_factory *a, grpc_socket_factory *b);
+
+grpc_socket_factory *grpc_socket_factory_ref(grpc_socket_factory *factory);
+void grpc_socket_factory_unref(grpc_socket_factory *factory);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_SOCKET_FACTORY_POSIX_H */
diff --git a/src/core/lib/iomgr/socket_utils_common_posix.c b/src/core/lib/iomgr/socket_utils_common_posix.c
index 88e9ade253..bbe642d0fb 100644
--- a/src/core/lib/iomgr/socket_utils_common_posix.c
+++ b/src/core/lib/iomgr/socket_utils_common_posix.c
@@ -90,7 +90,7 @@ grpc_error *grpc_set_socket_no_sigpipe_if_possible(int fd) {
     return GRPC_OS_ERROR(errno, "getsockopt(SO_NOSIGPIPE)");
   }
   if ((newval != 0) != (val != 0)) {
-    return GRPC_ERROR_CREATE("Failed to set SO_NOSIGPIPE");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed to set SO_NOSIGPIPE");
   }
 #endif
   return GRPC_ERROR_NONE;
@@ -164,7 +164,7 @@ grpc_error *grpc_set_socket_reuse_addr(int fd, int reuse) {
     return GRPC_OS_ERROR(errno, "getsockopt(SO_REUSEADDR)");
   }
   if ((newval != 0) != val) {
-    return GRPC_ERROR_CREATE("Failed to set SO_REUSEADDR");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed to set SO_REUSEADDR");
   }
 
   return GRPC_ERROR_NONE;
@@ -173,7 +173,8 @@ grpc_error *grpc_set_socket_reuse_addr(int fd, int reuse) {
 /* set a socket to reuse old addresses */
 grpc_error *grpc_set_socket_reuse_port(int fd, int reuse) {
 #ifndef SO_REUSEPORT
-  return GRPC_ERROR_CREATE("SO_REUSEPORT unavailable on compiling system");
+  return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+      "SO_REUSEPORT unavailable on compiling system");
 #else
   int val = (reuse != 0);
   int newval;
@@ -185,7 +186,7 @@ grpc_error *grpc_set_socket_reuse_port(int fd, int reuse) {
     return GRPC_OS_ERROR(errno, "getsockopt(SO_REUSEPORT)");
   }
   if ((newval != 0) != val) {
-    return GRPC_ERROR_CREATE("Failed to set SO_REUSEPORT");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed to set SO_REUSEPORT");
   }
 
   return GRPC_ERROR_NONE;
@@ -204,7 +205,7 @@ grpc_error *grpc_set_socket_low_latency(int fd, int low_latency) {
     return GRPC_OS_ERROR(errno, "getsockopt(TCP_NODELAY)");
   }
   if ((newval != 0) != val) {
-    return GRPC_ERROR_CREATE("Failed to set TCP_NODELAY");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed to set TCP_NODELAY");
   }
   return GRPC_ERROR_NONE;
 }
@@ -213,7 +214,7 @@ grpc_error *grpc_set_socket_low_latency(int fd, int low_latency) {
 grpc_error *grpc_set_socket_with_mutator(int fd, grpc_socket_mutator *mutator) {
   GPR_ASSERT(mutator);
   if (!grpc_socket_mutator_mutate_fd(mutator, fd)) {
-    return GRPC_ERROR_CREATE("grpc_socket_mutator failed.");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("grpc_socket_mutator failed.");
   }
   return GRPC_ERROR_NONE;
 }
@@ -268,7 +269,8 @@ static grpc_error *error_for_fd(int fd, const grpc_resolved_address *addr) {
   char *addr_str;
   grpc_sockaddr_to_string(&addr_str, addr, 0);
   grpc_error *err = grpc_error_set_str(GRPC_OS_ERROR(errno, "socket"),
-                                       GRPC_ERROR_STR_TARGET_ADDRESS, addr_str);
+                                       GRPC_ERROR_STR_TARGET_ADDRESS,
+                                       grpc_slice_from_copied_string(addr_str));
   gpr_free(addr_str);
   return err;
 }
@@ -276,11 +278,25 @@ static grpc_error *error_for_fd(int fd, const grpc_resolved_address *addr) {
 grpc_error *grpc_create_dualstack_socket(
     const grpc_resolved_address *resolved_addr, int type, int protocol,
     grpc_dualstack_mode *dsmode, int *newfd) {
+  return grpc_create_dualstack_socket_using_factory(NULL, resolved_addr, type,
+                                                    protocol, dsmode, newfd);
+}
+
+static int create_socket(grpc_socket_factory *factory, int domain, int type,
+                         int protocol) {
+  return (factory != NULL)
+             ? grpc_socket_factory_socket(factory, domain, type, protocol)
+             : socket(domain, type, protocol);
+}
+
+grpc_error *grpc_create_dualstack_socket_using_factory(
+    grpc_socket_factory *factory, const grpc_resolved_address *resolved_addr,
+    int type, int protocol, grpc_dualstack_mode *dsmode, int *newfd) {
   const struct sockaddr *addr = (const struct sockaddr *)resolved_addr->addr;
   int family = addr->sa_family;
   if (family == AF_INET6) {
     if (grpc_ipv6_loopback_available()) {
-      *newfd = socket(family, type, protocol);
+      *newfd = create_socket(factory, family, type, protocol);
     } else {
       *newfd = -1;
       errno = EAFNOSUPPORT;
@@ -302,7 +318,7 @@ grpc_error *grpc_create_dualstack_socket(
     family = AF_INET;
   }
   *dsmode = family == AF_INET ? GRPC_DSMODE_IPV4 : GRPC_DSMODE_NONE;
-  *newfd = socket(family, type, protocol);
+  *newfd = create_socket(factory, family, type, protocol);
   return error_for_fd(*newfd, resolved_addr);
 }
 
diff --git a/src/core/lib/iomgr/socket_utils_posix.h b/src/core/lib/iomgr/socket_utils_posix.h
index e84d3781a1..2c2fc95ff9 100644
--- a/src/core/lib/iomgr/socket_utils_posix.h
+++ b/src/core/lib/iomgr/socket_utils_posix.h
@@ -41,6 +41,7 @@
 
 #include <grpc/impl/codegen/grpc_types.h>
 #include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/iomgr/socket_factory_posix.h"
 #include "src/core/lib/iomgr/socket_mutator.h"
 
 /* a wrapper for accept or accept4 */
@@ -137,4 +138,10 @@ grpc_error *grpc_create_dualstack_socket(const grpc_resolved_address *addr,
                                          grpc_dualstack_mode *dsmode,
                                          int *newfd);
 
+/* Same as grpc_create_dualstack_socket(), but use the given socket factory (if
+   non-null) to create the socket, rather than calling socket() directly. */
+grpc_error *grpc_create_dualstack_socket_using_factory(
+    grpc_socket_factory *factory, const grpc_resolved_address *addr, int type,
+    int protocol, grpc_dualstack_mode *dsmode, int *newfd);
+
 #endif /* GRPC_CORE_LIB_IOMGR_SOCKET_UTILS_POSIX_H */
diff --git a/src/core/lib/iomgr/tcp_client_posix.c b/src/core/lib/iomgr/tcp_client_posix.c
index 0144192b71..a108b10da6 100644
--- a/src/core/lib/iomgr/tcp_client_posix.c
+++ b/src/core/lib/iomgr/tcp_client_posix.c
@@ -121,8 +121,8 @@ static void tc_on_alarm(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
   }
   gpr_mu_lock(&ac->mu);
   if (ac->fd != NULL) {
-    grpc_fd_shutdown(exec_ctx, ac->fd,
-                     GRPC_ERROR_CREATE("connect() timed out"));
+    grpc_fd_shutdown(exec_ctx, ac->fd, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                           "connect() timed out"));
   }
   done = (--ac->refs == 0);
   gpr_mu_unlock(&ac->mu);
@@ -191,7 +191,8 @@ static void on_writable(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
   gpr_mu_lock(&ac->mu);
   if (error != GRPC_ERROR_NONE) {
     error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, "Timeout occurred");
+        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                           grpc_slice_from_static_string("Timeout occurred"));
     goto finish;
   }
 
@@ -252,12 +253,17 @@ finish:
   gpr_mu_unlock(&ac->mu);
   if (error != GRPC_ERROR_NONE) {
     char *error_descr;
-    gpr_asprintf(&error_descr, "Failed to connect to remote host: %s",
-                 grpc_error_get_str(error, GRPC_ERROR_STR_DESCRIPTION));
-    error = grpc_error_set_str(error, GRPC_ERROR_STR_DESCRIPTION, error_descr);
+    grpc_slice str;
+    bool ret = grpc_error_get_str(error, GRPC_ERROR_STR_DESCRIPTION, &str);
+    GPR_ASSERT(ret);
+    char *desc = grpc_slice_to_c_string(str);
+    gpr_asprintf(&error_descr, "Failed to connect to remote host: %s", desc);
+    error = grpc_error_set_str(error, GRPC_ERROR_STR_DESCRIPTION,
+                               grpc_slice_from_copied_string(error_descr));
     gpr_free(error_descr);
-    error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_TARGET_ADDRESS, ac->addr_str);
+    gpr_free(desc);
+    error = grpc_error_set_str(error, GRPC_ERROR_STR_TARGET_ADDRESS,
+                               grpc_slice_from_copied_string(ac->addr_str));
   }
   if (done) {
     gpr_mu_destroy(&ac->mu);
diff --git a/src/core/lib/iomgr/tcp_client_uv.c b/src/core/lib/iomgr/tcp_client_uv.c
index 618483d9cb..682c24ed56 100644
--- a/src/core/lib/iomgr/tcp_client_uv.c
+++ b/src/core/lib/iomgr/tcp_client_uv.c
@@ -100,17 +100,21 @@ static void uv_tc_on_connect(uv_connect_t *req, int status) {
     *connect->endpoint = grpc_tcp_create(
         connect->tcp_handle, connect->resource_quota, connect->addr_name);
   } else {
-    error = GRPC_ERROR_CREATE("Failed to connect to remote host");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Failed to connect to remote host");
     error = grpc_error_set_int(error, GRPC_ERROR_INT_ERRNO, -status);
     error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, uv_strerror(status));
+        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                           grpc_slice_from_static_string(uv_strerror(status)));
     if (status == UV_ECANCELED) {
-      error = grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
-                                 "Timeout occurred");
+      error =
+          grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                             grpc_slice_from_static_string("Timeout occurred"));
       // This should only happen if the handle is already closed
     } else {
-      error = grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
-                                 uv_strerror(status));
+      error = grpc_error_set_str(
+          error, GRPC_ERROR_STR_OS_ERROR,
+          grpc_slice_from_static_string(uv_strerror(status)));
       uv_close((uv_handle_t *)connect->tcp_handle, tcp_close_callback);
     }
   }
diff --git a/src/core/lib/iomgr/tcp_client_windows.c b/src/core/lib/iomgr/tcp_client_windows.c
index c8dc9e64bd..a356564766 100644
--- a/src/core/lib/iomgr/tcp_client_windows.c
+++ b/src/core/lib/iomgr/tcp_client_windows.c
@@ -123,7 +123,7 @@ static void on_connect(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
         socket = NULL;
       }
     } else {
-      error = GRPC_ERROR_CREATE("socket is null");
+      error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("socket is null");
     }
   }
 
@@ -238,8 +238,9 @@ failure:
   GPR_ASSERT(error != GRPC_ERROR_NONE);
   char *target_uri = grpc_sockaddr_to_uri(addr);
   grpc_error *final_error = grpc_error_set_str(
-      GRPC_ERROR_CREATE_REFERENCING("Failed to connect", &error, 1),
-      GRPC_ERROR_STR_TARGET_ADDRESS, target_uri);
+      GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING("Failed to connect",
+                                                       &error, 1),
+      GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(target_uri));
   GRPC_ERROR_UNREF(error);
   if (socket != NULL) {
     grpc_winsocket_destroy(socket);
diff --git a/src/core/lib/iomgr/tcp_posix.c b/src/core/lib/iomgr/tcp_posix.c
index a4381f8fc9..4d7cf3ff51 100644
--- a/src/core/lib/iomgr/tcp_posix.c
+++ b/src/core/lib/iomgr/tcp_posix.c
@@ -111,7 +111,8 @@ typedef struct {
 static grpc_error *tcp_annotate_error(grpc_error *src_error, grpc_tcp *tcp) {
   return grpc_error_set_str(
       grpc_error_set_int(src_error, GRPC_ERROR_INT_FD, tcp->fd),
-      GRPC_ERROR_STR_TARGET_ADDRESS, tcp->peer_string);
+      GRPC_ERROR_STR_TARGET_ADDRESS,
+      grpc_slice_from_copied_string(tcp->peer_string));
 }
 
 static void tcp_handle_read(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
@@ -246,8 +247,10 @@ static void tcp_do_read(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
   } else if (read_bytes == 0) {
     /* 0 read size ==> end of stream */
     grpc_slice_buffer_reset_and_unref_internal(exec_ctx, tcp->incoming_buffer);
-    call_read_cb(exec_ctx, tcp,
-                 tcp_annotate_error(GRPC_ERROR_CREATE("Socket closed"), tcp));
+    call_read_cb(
+        exec_ctx, tcp,
+        tcp_annotate_error(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Socket closed"), tcp));
     TCP_UNREF(exec_ctx, tcp, "read");
   } else {
     GPR_ASSERT((size_t)read_bytes <= tcp->incoming_buffer->length);
@@ -464,10 +467,12 @@ static void tcp_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
 
   if (buf->length == 0) {
     GPR_TIMER_END("tcp_write", 0);
-    grpc_closure_sched(exec_ctx, cb,
-                       grpc_fd_is_shutdown(tcp->em_fd)
-                           ? tcp_annotate_error(GRPC_ERROR_CREATE("EOF"), tcp)
-                           : GRPC_ERROR_NONE);
+    grpc_closure_sched(
+        exec_ctx, cb,
+        grpc_fd_is_shutdown(tcp->em_fd)
+            ? tcp_annotate_error(GRPC_ERROR_CREATE_FROM_STATIC_STRING("EOF"),
+                                 tcp)
+            : GRPC_ERROR_NONE);
     return;
   }
   tcp->outgoing_buffer = buf;
diff --git a/src/core/lib/iomgr/tcp_server_posix.c b/src/core/lib/iomgr/tcp_server_posix.c
index 5f286a6723..d6a017cf7f 100644
--- a/src/core/lib/iomgr/tcp_server_posix.c
+++ b/src/core/lib/iomgr/tcp_server_posix.c
@@ -44,11 +44,8 @@
 
 #include <errno.h>
 #include <fcntl.h>
-#include <ifaddrs.h>
-#include <limits.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
-#include <stdio.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
@@ -67,82 +64,10 @@
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/socket_utils_posix.h"
 #include "src/core/lib/iomgr/tcp_posix.h"
+#include "src/core/lib/iomgr/tcp_server_utils_posix.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
 #include "src/core/lib/support/string.h"
 
-#define MIN_SAFE_ACCEPT_QUEUE_SIZE 100
-
-static gpr_once s_init_max_accept_queue_size;
-static int s_max_accept_queue_size;
-
-/* one listening port */
-typedef struct grpc_tcp_listener grpc_tcp_listener;
-struct grpc_tcp_listener {
-  int fd;
-  grpc_fd *emfd;
-  grpc_tcp_server *server;
-  grpc_resolved_address addr;
-  int port;
-  unsigned port_index;
-  unsigned fd_index;
-  grpc_closure read_closure;
-  grpc_closure destroyed_closure;
-  struct grpc_tcp_listener *next;
-  /* sibling is a linked list of all listeners for a given port. add_port and
-     clone_port place all new listeners in the same sibling list. A member of
-     the 'sibling' list is also a member of the 'next' list. The head of each
-     sibling list has is_sibling==0, and subsequent members of sibling lists
-     have is_sibling==1. is_sibling allows separate sibling lists to be
-     identified while iterating through 'next'. */
-  struct grpc_tcp_listener *sibling;
-  int is_sibling;
-};
-
-/* the overall server */
-struct grpc_tcp_server {
-  gpr_refcount refs;
-  /* Called whenever accept() succeeds on a server port. */
-  grpc_tcp_server_cb on_accept_cb;
-  void *on_accept_cb_arg;
-
-  gpr_mu mu;
-
-  /* active port count: how many ports are actually still listening */
-  size_t active_ports;
-  /* destroyed port count: how many ports are completely destroyed */
-  size_t destroyed_ports;
-
-  /* is this server shutting down? */
-  bool shutdown;
-  /* have listeners been shutdown? */
-  bool shutdown_listeners;
-  /* use SO_REUSEPORT */
-  bool so_reuseport;
-  /* expand wildcard addresses to a list of all local addresses */
-  bool expand_wildcard_addrs;
-
-  /* linked list of server ports */
-  grpc_tcp_listener *head;
-  grpc_tcp_listener *tail;
-  unsigned nports;
-
-  /* List of closures passed to shutdown_starting_add(). */
-  grpc_closure_list shutdown_starting;
-
-  /* shutdown callback */
-  grpc_closure *shutdown_complete;
-
-  /* all pollsets interested in new connections */
-  grpc_pollset **pollsets;
-  /* number of pollsets in the pollsets array */
-  size_t pollset_count;
-
-  /* next pollset to assign a channel to */
-  gpr_atm next_pollset_to_assign;
-
-  grpc_resource_quota *resource_quota;
-};
-
 static gpr_once check_init = GPR_ONCE_INIT;
 static bool has_so_reuseport = false;
 
@@ -175,8 +100,8 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
       } else {
         grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
-        return GRPC_ERROR_CREATE(GRPC_ARG_ALLOW_REUSEPORT
-                                 " must be an integer");
+        return GRPC_ERROR_CREATE_FROM_STATIC_STRING(GRPC_ARG_ALLOW_REUSEPORT
+                                                    " must be an integer");
       }
     } else if (0 == strcmp(GRPC_ARG_RESOURCE_QUOTA, args->args[i].key)) {
       if (args->args[i].type == GRPC_ARG_POINTER) {
@@ -186,8 +111,8 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
       } else {
         grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
-        return GRPC_ERROR_CREATE(GRPC_ARG_RESOURCE_QUOTA
-                                 " must be a pointer to a buffer pool");
+        return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+            GRPC_ARG_RESOURCE_QUOTA " must be a pointer to a buffer pool");
       }
     } else if (0 == strcmp(GRPC_ARG_EXPAND_WILDCARD_ADDRS, args->args[i].key)) {
       if (args->args[i].type == GRPC_ARG_INTEGER) {
@@ -195,8 +120,8 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
       } else {
         grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
-        return GRPC_ERROR_CREATE(GRPC_ARG_EXPAND_WILDCARD_ADDRS
-                                 " must be an integer");
+        return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+            GRPC_ARG_EXPAND_WILDCARD_ADDRS " must be an integer");
       }
     }
   }
@@ -260,10 +185,7 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
   /* delete ALL the things */
   gpr_mu_lock(&s->mu);
 
-  if (!s->shutdown) {
-    gpr_mu_unlock(&s->mu);
-    return;
-  }
+  GPR_ASSERT(s->shutdown);
 
   if (s->head) {
     grpc_tcp_listener *sp;
@@ -291,8 +213,8 @@ static void tcp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
   if (s->active_ports) {
     grpc_tcp_listener *sp;
     for (sp = s->head; sp; sp = sp->next) {
-      grpc_fd_shutdown(exec_ctx, sp->emfd,
-                       GRPC_ERROR_CREATE("Server destroyed"));
+      grpc_fd_shutdown(exec_ctx, sp->emfd, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                               "Server destroyed"));
     }
     gpr_mu_unlock(&s->mu);
   } else {
@@ -301,99 +223,6 @@ static void tcp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
   }
 }
 
-/* get max listen queue size on linux */
-static void init_max_accept_queue_size(void) {
-  int n = SOMAXCONN;
-  char buf[64];
-  FILE *fp = fopen("/proc/sys/net/core/somaxconn", "r");
-  if (fp == NULL) {
-    /* 2.4 kernel. */
-    s_max_accept_queue_size = SOMAXCONN;
-    return;
-  }
-  if (fgets(buf, sizeof buf, fp)) {
-    char *end;
-    long i = strtol(buf, &end, 10);
-    if (i > 0 && i <= INT_MAX && end && *end == 0) {
-      n = (int)i;
-    }
-  }
-  fclose(fp);
-  s_max_accept_queue_size = n;
-
-  if (s_max_accept_queue_size < MIN_SAFE_ACCEPT_QUEUE_SIZE) {
-    gpr_log(GPR_INFO,
-            "Suspiciously small accept queue (%d) will probably lead to "
-            "connection drops",
-            s_max_accept_queue_size);
-  }
-}
-
-static int get_max_accept_queue_size(void) {
-  gpr_once_init(&s_init_max_accept_queue_size, init_max_accept_queue_size);
-  return s_max_accept_queue_size;
-}
-
-/* Prepare a recently-created socket for listening. */
-static grpc_error *prepare_socket(int fd, const grpc_resolved_address *addr,
-                                  bool so_reuseport, int *port) {
-  grpc_resolved_address sockname_temp;
-  grpc_error *err = GRPC_ERROR_NONE;
-
-  GPR_ASSERT(fd >= 0);
-
-  if (so_reuseport && !grpc_is_unix_socket(addr)) {
-    err = grpc_set_socket_reuse_port(fd, 1);
-    if (err != GRPC_ERROR_NONE) goto error;
-  }
-
-  err = grpc_set_socket_nonblocking(fd, 1);
-  if (err != GRPC_ERROR_NONE) goto error;
-  err = grpc_set_socket_cloexec(fd, 1);
-  if (err != GRPC_ERROR_NONE) goto error;
-  if (!grpc_is_unix_socket(addr)) {
-    err = grpc_set_socket_low_latency(fd, 1);
-    if (err != GRPC_ERROR_NONE) goto error;
-    err = grpc_set_socket_reuse_addr(fd, 1);
-    if (err != GRPC_ERROR_NONE) goto error;
-  }
-  err = grpc_set_socket_no_sigpipe_if_possible(fd);
-  if (err != GRPC_ERROR_NONE) goto error;
-
-  GPR_ASSERT(addr->len < ~(socklen_t)0);
-  if (bind(fd, (struct sockaddr *)addr->addr, (socklen_t)addr->len) < 0) {
-    err = GRPC_OS_ERROR(errno, "bind");
-    goto error;
-  }
-
-  if (listen(fd, get_max_accept_queue_size()) < 0) {
-    err = GRPC_OS_ERROR(errno, "listen");
-    goto error;
-  }
-
-  sockname_temp.len = sizeof(struct sockaddr_storage);
-
-  if (getsockname(fd, (struct sockaddr *)sockname_temp.addr,
-                  (socklen_t *)&sockname_temp.len) < 0) {
-    err = GRPC_OS_ERROR(errno, "getsockname");
-    goto error;
-  }
-
-  *port = grpc_sockaddr_get_port(&sockname_temp);
-  return GRPC_ERROR_NONE;
-
-error:
-  GPR_ASSERT(err != GRPC_ERROR_NONE);
-  if (fd >= 0) {
-    close(fd);
-  }
-  grpc_error *ret = grpc_error_set_int(
-      GRPC_ERROR_CREATE_REFERENCING("Unable to configure socket", &err, 1),
-      GRPC_ERROR_INT_FD, fd);
-  GRPC_ERROR_UNREF(err);
-  return ret;
-}
-
 /* event manager callback when reads are ready */
 static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *err) {
   grpc_tcp_listener *sp = arg;
@@ -469,7 +298,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *err) {
 
 error:
   gpr_mu_lock(&sp->server->mu);
-  if (0 == --sp->server->active_ports) {
+  if (0 == --sp->server->active_ports && sp->server->shutdown) {
     gpr_mu_unlock(&sp->server->mu);
     deactivated_all_ports(exec_ctx, sp->server);
   } else {
@@ -477,216 +306,6 @@ error:
   }
 }
 
-static grpc_error *add_socket_to_server(grpc_tcp_server *s, int fd,
-                                        const grpc_resolved_address *addr,
-                                        unsigned port_index, unsigned fd_index,
-                                        grpc_tcp_listener **listener) {
-  grpc_tcp_listener *sp = NULL;
-  int port = -1;
-  char *addr_str;
-  char *name;
-
-  grpc_error *err = prepare_socket(fd, addr, s->so_reuseport, &port);
-  if (err == GRPC_ERROR_NONE) {
-    GPR_ASSERT(port > 0);
-    grpc_sockaddr_to_string(&addr_str, addr, 1);
-    gpr_asprintf(&name, "tcp-server-listener:%s", addr_str);
-    gpr_mu_lock(&s->mu);
-    s->nports++;
-    GPR_ASSERT(!s->on_accept_cb && "must add ports before starting server");
-    sp = gpr_malloc(sizeof(grpc_tcp_listener));
-    sp->next = NULL;
-    if (s->head == NULL) {
-      s->head = sp;
-    } else {
-      s->tail->next = sp;
-    }
-    s->tail = sp;
-    sp->server = s;
-    sp->fd = fd;
-    sp->emfd = grpc_fd_create(fd, name);
-    memcpy(&sp->addr, addr, sizeof(grpc_resolved_address));
-    sp->port = port;
-    sp->port_index = port_index;
-    sp->fd_index = fd_index;
-    sp->is_sibling = 0;
-    sp->sibling = NULL;
-    GPR_ASSERT(sp->emfd);
-    gpr_mu_unlock(&s->mu);
-    gpr_free(addr_str);
-    gpr_free(name);
-  }
-
-  *listener = sp;
-  return err;
-}
-
-/* If successful, add a listener to s for addr, set *dsmode for the socket, and
-   return the *listener. */
-static grpc_error *add_addr_to_server(grpc_tcp_server *s,
-                                      const grpc_resolved_address *addr,
-                                      unsigned port_index, unsigned fd_index,
-                                      grpc_dualstack_mode *dsmode,
-                                      grpc_tcp_listener **listener) {
-  grpc_resolved_address addr4_copy;
-  int fd;
-  grpc_error *err =
-      grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, dsmode, &fd);
-  if (err != GRPC_ERROR_NONE) {
-    return err;
-  }
-  if (*dsmode == GRPC_DSMODE_IPV4 &&
-      grpc_sockaddr_is_v4mapped(addr, &addr4_copy)) {
-    addr = &addr4_copy;
-  }
-  return add_socket_to_server(s, fd, addr, port_index, fd_index, listener);
-}
-
-/* Bind to "::" to get a port number not used by any address. */
-static grpc_error *get_unused_port(int *port) {
-  grpc_resolved_address wild;
-  grpc_sockaddr_make_wildcard6(0, &wild);
-  grpc_dualstack_mode dsmode;
-  int fd;
-  grpc_error *err =
-      grpc_create_dualstack_socket(&wild, SOCK_STREAM, 0, &dsmode, &fd);
-  if (err != GRPC_ERROR_NONE) {
-    return err;
-  }
-  if (dsmode == GRPC_DSMODE_IPV4) {
-    grpc_sockaddr_make_wildcard4(0, &wild);
-  }
-  if (bind(fd, (const struct sockaddr *)wild.addr, (socklen_t)wild.len) != 0) {
-    err = GRPC_OS_ERROR(errno, "bind");
-    close(fd);
-    return err;
-  }
-  if (getsockname(fd, (struct sockaddr *)wild.addr, (socklen_t *)&wild.len) !=
-      0) {
-    err = GRPC_OS_ERROR(errno, "getsockname");
-    close(fd);
-    return err;
-  }
-  close(fd);
-  *port = grpc_sockaddr_get_port(&wild);
-  return *port <= 0 ? GRPC_ERROR_CREATE("Bad port") : GRPC_ERROR_NONE;
-}
-
-/* Return the listener in s with address addr or NULL. */
-static grpc_tcp_listener *find_listener_with_addr(grpc_tcp_server *s,
-                                                  grpc_resolved_address *addr) {
-  grpc_tcp_listener *l;
-  gpr_mu_lock(&s->mu);
-  for (l = s->head; l != NULL; l = l->next) {
-    if (l->addr.len != addr->len) {
-      continue;
-    }
-    if (memcmp(l->addr.addr, addr->addr, addr->len) == 0) {
-      break;
-    }
-  }
-  gpr_mu_unlock(&s->mu);
-  return l;
-}
-
-/* Get all addresses assigned to network interfaces on the machine and create a
-   listener for each. requested_port is the port to use for every listener, or 0
-   to select one random port that will be used for every listener. Set *out_port
-   to the port selected. Return GRPC_ERROR_NONE only if all listeners were
-   added. */
-static grpc_error *add_all_local_addrs_to_server(grpc_tcp_server *s,
-                                                 unsigned port_index,
-                                                 int requested_port,
-                                                 int *out_port) {
-  struct ifaddrs *ifa = NULL;
-  struct ifaddrs *ifa_it;
-  unsigned fd_index = 0;
-  grpc_tcp_listener *sp = NULL;
-  grpc_error *err = GRPC_ERROR_NONE;
-  if (requested_port == 0) {
-    /* Note: There could be a race where some local addrs can listen on the
-       selected port and some can't. The sane way to handle this would be to
-       retry by recreating the whole grpc_tcp_server. Backing out individual
-       listeners and orphaning the FDs looks like too much trouble. */
-    if ((err = get_unused_port(&requested_port)) != GRPC_ERROR_NONE) {
-      return err;
-    } else if (requested_port <= 0) {
-      return GRPC_ERROR_CREATE("Bad get_unused_port()");
-    }
-    gpr_log(GPR_DEBUG, "Picked unused port %d", requested_port);
-  }
-  if (getifaddrs(&ifa) != 0 || ifa == NULL) {
-    return GRPC_OS_ERROR(errno, "getifaddrs");
-  }
-  for (ifa_it = ifa; ifa_it != NULL; ifa_it = ifa_it->ifa_next) {
-    grpc_resolved_address addr;
-    char *addr_str = NULL;
-    grpc_dualstack_mode dsmode;
-    grpc_tcp_listener *new_sp = NULL;
-    const char *ifa_name = (ifa_it->ifa_name ? ifa_it->ifa_name : "<unknown>");
-    if (ifa_it->ifa_addr == NULL) {
-      continue;
-    } else if (ifa_it->ifa_addr->sa_family == AF_INET) {
-      addr.len = sizeof(struct sockaddr_in);
-    } else if (ifa_it->ifa_addr->sa_family == AF_INET6) {
-      addr.len = sizeof(struct sockaddr_in6);
-    } else {
-      continue;
-    }
-    memcpy(addr.addr, ifa_it->ifa_addr, addr.len);
-    if (!grpc_sockaddr_set_port(&addr, requested_port)) {
-      /* Should never happen, because we check sa_family above. */
-      err = GRPC_ERROR_CREATE("Failed to set port");
-      break;
-    }
-    if (grpc_sockaddr_to_string(&addr_str, &addr, 0) < 0) {
-      addr_str = gpr_strdup("<error>");
-    }
-    gpr_log(GPR_DEBUG,
-            "Adding local addr from interface %s flags 0x%x to server: %s",
-            ifa_name, ifa_it->ifa_flags, addr_str);
-    /* We could have multiple interfaces with the same address (e.g., bonding),
-       so look for duplicates. */
-    if (find_listener_with_addr(s, &addr) != NULL) {
-      gpr_log(GPR_DEBUG, "Skipping duplicate addr %s on interface %s", addr_str,
-              ifa_name);
-      gpr_free(addr_str);
-      continue;
-    }
-    if ((err = add_addr_to_server(s, &addr, port_index, fd_index, &dsmode,
-                                  &new_sp)) != GRPC_ERROR_NONE) {
-      char *err_str = NULL;
-      grpc_error *root_err;
-      if (gpr_asprintf(&err_str, "Failed to add listener: %s", addr_str) < 0) {
-        err_str = gpr_strdup("Failed to add listener");
-      }
-      root_err = GRPC_ERROR_CREATE(err_str);
-      gpr_free(err_str);
-      gpr_free(addr_str);
-      err = grpc_error_add_child(root_err, err);
-      break;
-    } else {
-      GPR_ASSERT(requested_port == new_sp->port);
-      ++fd_index;
-      if (sp != NULL) {
-        new_sp->is_sibling = 1;
-        sp->sibling = new_sp;
-      }
-      sp = new_sp;
-    }
-    gpr_free(addr_str);
-  }
-  freeifaddrs(ifa);
-  if (err != GRPC_ERROR_NONE) {
-    return err;
-  } else if (sp == NULL) {
-    return GRPC_ERROR_CREATE("No local addresses");
-  } else {
-    *out_port = sp->port;
-    return GRPC_ERROR_NONE;
-  }
-}
-
 /* Treat :: or 0.0.0.0 as a family-agnostic wildcard. */
 static grpc_error *add_wildcard_addrs_to_server(grpc_tcp_server *s,
                                                 unsigned port_index,
@@ -701,14 +320,16 @@ static grpc_error *add_wildcard_addrs_to_server(grpc_tcp_server *s,
   grpc_error *v6_err = GRPC_ERROR_NONE;
   grpc_error *v4_err = GRPC_ERROR_NONE;
   *out_port = -1;
-  if (s->expand_wildcard_addrs) {
-    return add_all_local_addrs_to_server(s, port_index, requested_port,
-                                         out_port);
+
+  if (grpc_tcp_server_have_ifaddrs() && s->expand_wildcard_addrs) {
+    return grpc_tcp_server_add_all_local_addrs(s, port_index, requested_port,
+                                               out_port);
   }
+
   grpc_sockaddr_make_wildcards(requested_port, &wild4, &wild6);
   /* Try listening on IPv6 first. */
-  if ((v6_err = add_addr_to_server(s, &wild6, port_index, fd_index, &dsmode,
-                                   &sp)) == GRPC_ERROR_NONE) {
+  if ((v6_err = grpc_tcp_server_add_addr(s, &wild6, port_index, fd_index,
+                                         &dsmode, &sp)) == GRPC_ERROR_NONE) {
     ++fd_index;
     requested_port = *out_port = sp->port;
     if (dsmode == GRPC_DSMODE_DUALSTACK || dsmode == GRPC_DSMODE_IPV4) {
@@ -717,8 +338,8 @@ static grpc_error *add_wildcard_addrs_to_server(grpc_tcp_server *s,
   }
   /* If we got a v6-only socket or nothing, try adding 0.0.0.0. */
   grpc_sockaddr_set_port(&wild4, requested_port);
-  if ((v4_err = add_addr_to_server(s, &wild4, port_index, fd_index, &dsmode,
-                                   &sp2)) == GRPC_ERROR_NONE) {
+  if ((v4_err = grpc_tcp_server_add_addr(s, &wild4, port_index, fd_index,
+                                         &dsmode, &sp2)) == GRPC_ERROR_NONE) {
     *out_port = sp2->port;
     if (sp != NULL) {
       sp2->is_sibling = 1;
@@ -726,12 +347,24 @@ static grpc_error *add_wildcard_addrs_to_server(grpc_tcp_server *s,
     }
   }
   if (*out_port > 0) {
-    GRPC_LOG_IF_ERROR("Failed to add :: listener", v6_err);
-    GRPC_LOG_IF_ERROR("Failed to add 0.0.0.0 listener", v4_err);
+    if (v6_err != GRPC_ERROR_NONE) {
+      gpr_log(GPR_INFO,
+              "Failed to add :: listener, "
+              "the environment may not support IPv6: %s",
+              grpc_error_string(v6_err));
+      GRPC_ERROR_UNREF(v6_err);
+    }
+    if (v4_err != GRPC_ERROR_NONE) {
+      gpr_log(GPR_INFO,
+              "Failed to add 0.0.0.0 listener, "
+              "the environment may not support IPv4: %s",
+              grpc_error_string(v4_err));
+      GRPC_ERROR_UNREF(v4_err);
+    }
     return GRPC_ERROR_NONE;
   } else {
-    grpc_error *root_err =
-        GRPC_ERROR_CREATE("Failed to add any wildcard listeners");
+    grpc_error *root_err = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Failed to add any wildcard listeners");
     GPR_ASSERT(v6_err != GRPC_ERROR_NONE && v4_err != GRPC_ERROR_NONE);
     root_err = grpc_error_add_child(root_err, v6_err);
     root_err = grpc_error_add_child(root_err, v4_err);
@@ -756,7 +389,7 @@ static grpc_error *clone_port(grpc_tcp_listener *listener, unsigned count) {
     err = grpc_create_dualstack_socket(&listener->addr, SOCK_STREAM, 0, &dsmode,
                                        &fd);
     if (err != GRPC_ERROR_NONE) return err;
-    err = prepare_socket(fd, &listener->addr, true, &port);
+    err = grpc_tcp_server_prepare_socket(fd, &listener->addr, true, &port);
     if (err != GRPC_ERROR_NONE) return err;
     listener->server->nports++;
     grpc_sockaddr_to_string(&addr_str, &listener->addr, 1);
@@ -828,7 +461,7 @@ grpc_error *grpc_tcp_server_add_port(grpc_tcp_server *s,
   if (grpc_sockaddr_to_v4mapped(addr, &addr6_v4mapped)) {
     addr = &addr6_v4mapped;
   }
-  if ((err = add_addr_to_server(s, addr, port_index, 0, &dsmode, &sp)) ==
+  if ((err = grpc_tcp_server_add_addr(s, addr, port_index, 0, &dsmode, &sp)) ==
       GRPC_ERROR_NONE) {
     *out_port = sp->port;
   }
@@ -951,7 +584,7 @@ void grpc_tcp_server_shutdown_listeners(grpc_exec_ctx *exec_ctx,
     grpc_tcp_listener *sp;
     for (sp = s->head; sp; sp = sp->next) {
       grpc_fd_shutdown(exec_ctx, sp->emfd,
-                       GRPC_ERROR_CREATE("Server shutdown"));
+                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server shutdown"));
     }
   }
   gpr_mu_unlock(&s->mu);
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix.h b/src/core/lib/iomgr/tcp_server_utils_posix.h
new file mode 100644
index 0000000000..f5dc8532f9
--- /dev/null
+++ b/src/core/lib/iomgr/tcp_server_utils_posix.h
@@ -0,0 +1,134 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H
+#define GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H
+
+#include "src/core/lib/iomgr/ev_posix.h"
+#include "src/core/lib/iomgr/resolve_address.h"
+#include "src/core/lib/iomgr/socket_utils_posix.h"
+#include "src/core/lib/iomgr/tcp_server.h"
+
+/* one listening port */
+typedef struct grpc_tcp_listener {
+  int fd;
+  grpc_fd *emfd;
+  grpc_tcp_server *server;
+  grpc_resolved_address addr;
+  int port;
+  unsigned port_index;
+  unsigned fd_index;
+  grpc_closure read_closure;
+  grpc_closure destroyed_closure;
+  struct grpc_tcp_listener *next;
+  /* sibling is a linked list of all listeners for a given port. add_port and
+     clone_port place all new listeners in the same sibling list. A member of
+     the 'sibling' list is also a member of the 'next' list. The head of each
+     sibling list has is_sibling==0, and subsequent members of sibling lists
+     have is_sibling==1. is_sibling allows separate sibling lists to be
+     identified while iterating through 'next'. */
+  struct grpc_tcp_listener *sibling;
+  int is_sibling;
+} grpc_tcp_listener;
+
+/* the overall server */
+struct grpc_tcp_server {
+  gpr_refcount refs;
+  /* Called whenever accept() succeeds on a server port. */
+  grpc_tcp_server_cb on_accept_cb;
+  void *on_accept_cb_arg;
+
+  gpr_mu mu;
+
+  /* active port count: how many ports are actually still listening */
+  size_t active_ports;
+  /* destroyed port count: how many ports are completely destroyed */
+  size_t destroyed_ports;
+
+  /* is this server shutting down? */
+  bool shutdown;
+  /* have listeners been shutdown? */
+  bool shutdown_listeners;
+  /* use SO_REUSEPORT */
+  bool so_reuseport;
+  /* expand wildcard addresses to a list of all local addresses */
+  bool expand_wildcard_addrs;
+
+  /* linked list of server ports */
+  grpc_tcp_listener *head;
+  grpc_tcp_listener *tail;
+  unsigned nports;
+
+  /* List of closures passed to shutdown_starting_add(). */
+  grpc_closure_list shutdown_starting;
+
+  /* shutdown callback */
+  grpc_closure *shutdown_complete;
+
+  /* all pollsets interested in new connections */
+  grpc_pollset **pollsets;
+  /* number of pollsets in the pollsets array */
+  size_t pollset_count;
+
+  /* next pollset to assign a channel to */
+  gpr_atm next_pollset_to_assign;
+
+  grpc_resource_quota *resource_quota;
+};
+
+/* If successful, add a listener to \a s for \a addr, set \a dsmode for the
+   socket, and return the \a listener. */
+grpc_error *grpc_tcp_server_add_addr(grpc_tcp_server *s,
+                                     const grpc_resolved_address *addr,
+                                     unsigned port_index, unsigned fd_index,
+                                     grpc_dualstack_mode *dsmode,
+                                     grpc_tcp_listener **listener);
+
+/* Get all addresses assigned to network interfaces on the machine and create a
+   listener for each. requested_port is the port to use for every listener, or 0
+   to select one random port that will be used for every listener. Set *out_port
+   to the port selected. Return GRPC_ERROR_NONE only if all listeners were
+   added. */
+grpc_error *grpc_tcp_server_add_all_local_addrs(grpc_tcp_server *s,
+                                                unsigned port_index,
+                                                int requested_port,
+                                                int *out_port);
+
+/* Prepare a recently-created socket for listening. */
+grpc_error *grpc_tcp_server_prepare_socket(int fd,
+                                           const grpc_resolved_address *addr,
+                                           bool so_reuseport, int *port);
+/* Ruturn true if the platform supports ifaddrs */
+bool grpc_tcp_server_have_ifaddrs(void);
+
+#endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H */
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_common.c b/src/core/lib/iomgr/tcp_server_utils_posix_common.c
new file mode 100644
index 0000000000..af2b00b4b5
--- /dev/null
+++ b/src/core/lib/iomgr/tcp_server_utils_posix_common.c
@@ -0,0 +1,221 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_POSIX_SOCKET
+
+#include "src/core/lib/iomgr/tcp_server_utils_posix.h"
+
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/sync.h>
+
+#include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/iomgr/sockaddr.h"
+#include "src/core/lib/iomgr/sockaddr_utils.h"
+#include "src/core/lib/iomgr/unix_sockets_posix.h"
+
+#define MIN_SAFE_ACCEPT_QUEUE_SIZE 100
+
+static gpr_once s_init_max_accept_queue_size;
+static int s_max_accept_queue_size;
+
+/* get max listen queue size on linux */
+static void init_max_accept_queue_size(void) {
+  int n = SOMAXCONN;
+  char buf[64];
+  FILE *fp = fopen("/proc/sys/net/core/somaxconn", "r");
+  if (fp == NULL) {
+    /* 2.4 kernel. */
+    s_max_accept_queue_size = SOMAXCONN;
+    return;
+  }
+  if (fgets(buf, sizeof buf, fp)) {
+    char *end;
+    long i = strtol(buf, &end, 10);
+    if (i > 0 && i <= INT_MAX && end && *end == 0) {
+      n = (int)i;
+    }
+  }
+  fclose(fp);
+  s_max_accept_queue_size = n;
+
+  if (s_max_accept_queue_size < MIN_SAFE_ACCEPT_QUEUE_SIZE) {
+    gpr_log(GPR_INFO,
+            "Suspiciously small accept queue (%d) will probably lead to "
+            "connection drops",
+            s_max_accept_queue_size);
+  }
+}
+
+static int get_max_accept_queue_size(void) {
+  gpr_once_init(&s_init_max_accept_queue_size, init_max_accept_queue_size);
+  return s_max_accept_queue_size;
+}
+
+static grpc_error *add_socket_to_server(grpc_tcp_server *s, int fd,
+                                        const grpc_resolved_address *addr,
+                                        unsigned port_index, unsigned fd_index,
+                                        grpc_tcp_listener **listener) {
+  grpc_tcp_listener *sp = NULL;
+  int port = -1;
+  char *addr_str;
+  char *name;
+
+  grpc_error *err =
+      grpc_tcp_server_prepare_socket(fd, addr, s->so_reuseport, &port);
+  if (err == GRPC_ERROR_NONE) {
+    GPR_ASSERT(port > 0);
+    grpc_sockaddr_to_string(&addr_str, addr, 1);
+    gpr_asprintf(&name, "tcp-server-listener:%s", addr_str);
+    gpr_mu_lock(&s->mu);
+    s->nports++;
+    GPR_ASSERT(!s->on_accept_cb && "must add ports before starting server");
+    sp = gpr_malloc(sizeof(grpc_tcp_listener));
+    sp->next = NULL;
+    if (s->head == NULL) {
+      s->head = sp;
+    } else {
+      s->tail->next = sp;
+    }
+    s->tail = sp;
+    sp->server = s;
+    sp->fd = fd;
+    sp->emfd = grpc_fd_create(fd, name);
+    memcpy(&sp->addr, addr, sizeof(grpc_resolved_address));
+    sp->port = port;
+    sp->port_index = port_index;
+    sp->fd_index = fd_index;
+    sp->is_sibling = 0;
+    sp->sibling = NULL;
+    GPR_ASSERT(sp->emfd);
+    gpr_mu_unlock(&s->mu);
+    gpr_free(addr_str);
+    gpr_free(name);
+  }
+
+  *listener = sp;
+  return err;
+}
+
+/* If successful, add a listener to s for addr, set *dsmode for the socket, and
+   return the *listener. */
+grpc_error *grpc_tcp_server_add_addr(grpc_tcp_server *s,
+                                     const grpc_resolved_address *addr,
+                                     unsigned port_index, unsigned fd_index,
+                                     grpc_dualstack_mode *dsmode,
+                                     grpc_tcp_listener **listener) {
+  grpc_resolved_address addr4_copy;
+  int fd;
+  grpc_error *err =
+      grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, dsmode, &fd);
+  if (err != GRPC_ERROR_NONE) {
+    return err;
+  }
+  if (*dsmode == GRPC_DSMODE_IPV4 &&
+      grpc_sockaddr_is_v4mapped(addr, &addr4_copy)) {
+    addr = &addr4_copy;
+  }
+  return add_socket_to_server(s, fd, addr, port_index, fd_index, listener);
+}
+
+/* Prepare a recently-created socket for listening. */
+grpc_error *grpc_tcp_server_prepare_socket(int fd,
+                                           const grpc_resolved_address *addr,
+                                           bool so_reuseport, int *port) {
+  grpc_resolved_address sockname_temp;
+  grpc_error *err = GRPC_ERROR_NONE;
+
+  GPR_ASSERT(fd >= 0);
+
+  if (so_reuseport && !grpc_is_unix_socket(addr)) {
+    err = grpc_set_socket_reuse_port(fd, 1);
+    if (err != GRPC_ERROR_NONE) goto error;
+  }
+
+  err = grpc_set_socket_nonblocking(fd, 1);
+  if (err != GRPC_ERROR_NONE) goto error;
+  err = grpc_set_socket_cloexec(fd, 1);
+  if (err != GRPC_ERROR_NONE) goto error;
+  if (!grpc_is_unix_socket(addr)) {
+    err = grpc_set_socket_low_latency(fd, 1);
+    if (err != GRPC_ERROR_NONE) goto error;
+    err = grpc_set_socket_reuse_addr(fd, 1);
+    if (err != GRPC_ERROR_NONE) goto error;
+  }
+  err = grpc_set_socket_no_sigpipe_if_possible(fd);
+  if (err != GRPC_ERROR_NONE) goto error;
+
+  GPR_ASSERT(addr->len < ~(socklen_t)0);
+  if (bind(fd, (struct sockaddr *)addr->addr, (socklen_t)addr->len) < 0) {
+    err = GRPC_OS_ERROR(errno, "bind");
+    goto error;
+  }
+
+  if (listen(fd, get_max_accept_queue_size()) < 0) {
+    err = GRPC_OS_ERROR(errno, "listen");
+    goto error;
+  }
+
+  sockname_temp.len = sizeof(struct sockaddr_storage);
+
+  if (getsockname(fd, (struct sockaddr *)sockname_temp.addr,
+                  (socklen_t *)&sockname_temp.len) < 0) {
+    err = GRPC_OS_ERROR(errno, "getsockname");
+    goto error;
+  }
+
+  *port = grpc_sockaddr_get_port(&sockname_temp);
+  return GRPC_ERROR_NONE;
+
+error:
+  GPR_ASSERT(err != GRPC_ERROR_NONE);
+  if (fd >= 0) {
+    close(fd);
+  }
+  grpc_error *ret =
+      grpc_error_set_int(GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                             "Unable to configure socket", &err, 1),
+                         GRPC_ERROR_INT_FD, fd);
+  GRPC_ERROR_UNREF(err);
+  return ret;
+}
+
+#endif /* GRPC_POSIX_SOCKET */
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.c b/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.c
new file mode 100644
index 0000000000..2078a68126
--- /dev/null
+++ b/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.c
@@ -0,0 +1,196 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_HAVE_IFADDRS
+
+#include "src/core/lib/iomgr/tcp_server_utils_posix.h"
+
+#include <errno.h>
+#include <ifaddrs.h>
+#include <stddef.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/iomgr/sockaddr.h"
+#include "src/core/lib/iomgr/sockaddr_utils.h"
+
+/* Return the listener in s with address addr or NULL. */
+static grpc_tcp_listener *find_listener_with_addr(grpc_tcp_server *s,
+                                                  grpc_resolved_address *addr) {
+  grpc_tcp_listener *l;
+  gpr_mu_lock(&s->mu);
+  for (l = s->head; l != NULL; l = l->next) {
+    if (l->addr.len != addr->len) {
+      continue;
+    }
+    if (memcmp(l->addr.addr, addr->addr, addr->len) == 0) {
+      break;
+    }
+  }
+  gpr_mu_unlock(&s->mu);
+  return l;
+}
+
+/* Bind to "::" to get a port number not used by any address. */
+static grpc_error *get_unused_port(int *port) {
+  grpc_resolved_address wild;
+  grpc_sockaddr_make_wildcard6(0, &wild);
+  grpc_dualstack_mode dsmode;
+  int fd;
+  grpc_error *err =
+      grpc_create_dualstack_socket(&wild, SOCK_STREAM, 0, &dsmode, &fd);
+  if (err != GRPC_ERROR_NONE) {
+    return err;
+  }
+  if (dsmode == GRPC_DSMODE_IPV4) {
+    grpc_sockaddr_make_wildcard4(0, &wild);
+  }
+  if (bind(fd, (const struct sockaddr *)wild.addr, (socklen_t)wild.len) != 0) {
+    err = GRPC_OS_ERROR(errno, "bind");
+    close(fd);
+    return err;
+  }
+  if (getsockname(fd, (struct sockaddr *)wild.addr, (socklen_t *)&wild.len) !=
+      0) {
+    err = GRPC_OS_ERROR(errno, "getsockname");
+    close(fd);
+    return err;
+  }
+  close(fd);
+  *port = grpc_sockaddr_get_port(&wild);
+  return *port <= 0 ? GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad port")
+                    : GRPC_ERROR_NONE;
+}
+
+grpc_error *grpc_tcp_server_add_all_local_addrs(grpc_tcp_server *s,
+                                                unsigned port_index,
+                                                int requested_port,
+                                                int *out_port) {
+  struct ifaddrs *ifa = NULL;
+  struct ifaddrs *ifa_it;
+  unsigned fd_index = 0;
+  grpc_tcp_listener *sp = NULL;
+  grpc_error *err = GRPC_ERROR_NONE;
+  if (requested_port == 0) {
+    /* Note: There could be a race where some local addrs can listen on the
+       selected port and some can't. The sane way to handle this would be to
+       retry by recreating the whole grpc_tcp_server. Backing out individual
+       listeners and orphaning the FDs looks like too much trouble. */
+    if ((err = get_unused_port(&requested_port)) != GRPC_ERROR_NONE) {
+      return err;
+    } else if (requested_port <= 0) {
+      return GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad get_unused_port()");
+    }
+    gpr_log(GPR_DEBUG, "Picked unused port %d", requested_port);
+  }
+  if (getifaddrs(&ifa) != 0 || ifa == NULL) {
+    return GRPC_OS_ERROR(errno, "getifaddrs");
+  }
+  for (ifa_it = ifa; ifa_it != NULL; ifa_it = ifa_it->ifa_next) {
+    grpc_resolved_address addr;
+    char *addr_str = NULL;
+    grpc_dualstack_mode dsmode;
+    grpc_tcp_listener *new_sp = NULL;
+    const char *ifa_name = (ifa_it->ifa_name ? ifa_it->ifa_name : "<unknown>");
+    if (ifa_it->ifa_addr == NULL) {
+      continue;
+    } else if (ifa_it->ifa_addr->sa_family == AF_INET) {
+      addr.len = sizeof(struct sockaddr_in);
+    } else if (ifa_it->ifa_addr->sa_family == AF_INET6) {
+      addr.len = sizeof(struct sockaddr_in6);
+    } else {
+      continue;
+    }
+    memcpy(addr.addr, ifa_it->ifa_addr, addr.len);
+    if (!grpc_sockaddr_set_port(&addr, requested_port)) {
+      /* Should never happen, because we check sa_family above. */
+      err = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed to set port");
+      break;
+    }
+    if (grpc_sockaddr_to_string(&addr_str, &addr, 0) < 0) {
+      addr_str = gpr_strdup("<error>");
+    }
+    gpr_log(GPR_DEBUG,
+            "Adding local addr from interface %s flags 0x%x to server: %s",
+            ifa_name, ifa_it->ifa_flags, addr_str);
+    /* We could have multiple interfaces with the same address (e.g., bonding),
+       so look for duplicates. */
+    if (find_listener_with_addr(s, &addr) != NULL) {
+      gpr_log(GPR_DEBUG, "Skipping duplicate addr %s on interface %s", addr_str,
+              ifa_name);
+      gpr_free(addr_str);
+      continue;
+    }
+    if ((err = grpc_tcp_server_add_addr(s, &addr, port_index, fd_index, &dsmode,
+                                        &new_sp)) != GRPC_ERROR_NONE) {
+      char *err_str = NULL;
+      grpc_error *root_err;
+      if (gpr_asprintf(&err_str, "Failed to add listener: %s", addr_str) < 0) {
+        err_str = gpr_strdup("Failed to add listener");
+      }
+      root_err = GRPC_ERROR_CREATE_FROM_COPIED_STRING(err_str);
+      gpr_free(err_str);
+      gpr_free(addr_str);
+      err = grpc_error_add_child(root_err, err);
+      break;
+    } else {
+      GPR_ASSERT(requested_port == new_sp->port);
+      ++fd_index;
+      if (sp != NULL) {
+        new_sp->is_sibling = 1;
+        sp->sibling = new_sp;
+      }
+      sp = new_sp;
+    }
+    gpr_free(addr_str);
+  }
+  freeifaddrs(ifa);
+  if (err != GRPC_ERROR_NONE) {
+    return err;
+  } else if (sp == NULL) {
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING("No local addresses");
+  } else {
+    *out_port = sp->port;
+    return GRPC_ERROR_NONE;
+  }
+}
+
+bool grpc_tcp_server_have_ifaddrs(void) { return true; }
+
+#endif /* GRPC_HAVE_IFADDRS */
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_noifaddrs.c b/src/core/lib/iomgr/tcp_server_utils_posix_noifaddrs.c
new file mode 100644
index 0000000000..d6a1a0693e
--- /dev/null
+++ b/src/core/lib/iomgr/tcp_server_utils_posix_noifaddrs.c
@@ -0,0 +1,49 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/iomgr/port.h"
+
+#if defined(GRPC_POSIX_SOCKET) && !defined(GRPC_HAVE_IFADDRS)
+
+#include "src/core/lib/iomgr/tcp_server_utils_posix.h"
+
+grpc_error *grpc_tcp_server_add_all_local_addrs(grpc_tcp_server *s,
+                                                unsigned port_index,
+                                                int requested_port,
+                                                int *out_port) {
+  return GRPC_ERROR_CREATE_FROM_STATIC_STRING("no ifaddrs available");
+}
+
+bool grpc_tcp_server_have_ifaddrs(void) { return false; }
+
+#endif /* defined(GRPC_POSIX_SOCKET) && !defined(GRPC_HAVE_IFADDRS) */
diff --git a/src/core/lib/iomgr/tcp_server_uv.c b/src/core/lib/iomgr/tcp_server_uv.c
index eed2773f8a..e9246948f5 100644
--- a/src/core/lib/iomgr/tcp_server_uv.c
+++ b/src/core/lib/iomgr/tcp_server_uv.c
@@ -95,8 +95,8 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
       } else {
         grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
-        return GRPC_ERROR_CREATE(GRPC_ARG_RESOURCE_QUOTA
-                                 " must be a pointer to a buffer pool");
+        return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+            GRPC_ARG_RESOURCE_QUOTA " must be a pointer to a buffer pool");
       }
     }
   }
@@ -244,17 +244,19 @@ static grpc_error *add_socket_to_server(grpc_tcp_server *s, uv_tcp_t *handle,
   // The last argument to uv_tcp_bind is flags
   status = uv_tcp_bind(handle, (struct sockaddr *)addr->addr, 0);
   if (status != 0) {
-    error = GRPC_ERROR_CREATE("Failed to bind to port");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed to bind to port");
     error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, uv_strerror(status));
+        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                           grpc_slice_from_static_string(uv_strerror(status)));
     return error;
   }
 
   status = uv_listen((uv_stream_t *)handle, SOMAXCONN, on_connect);
   if (status != 0) {
-    error = GRPC_ERROR_CREATE("Failed to listen to port");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed to listen to port");
     error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, uv_strerror(status));
+        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                           grpc_slice_from_static_string(uv_strerror(status)));
     return error;
   }
 
@@ -262,9 +264,10 @@ static grpc_error *add_socket_to_server(grpc_tcp_server *s, uv_tcp_t *handle,
   status = uv_tcp_getsockname(handle, (struct sockaddr *)&sockname_temp.addr,
                               (int *)&sockname_temp.len);
   if (status != 0) {
-    error = GRPC_ERROR_CREATE("getsockname failed");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("getsockname failed");
     error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, uv_strerror(status));
+        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                           grpc_slice_from_static_string(uv_strerror(status)));
     return error;
   }
 
@@ -346,15 +349,17 @@ grpc_error *grpc_tcp_server_add_port(grpc_tcp_server *s,
   if (status == 0) {
     error = add_socket_to_server(s, handle, addr, port_index, &sp);
   } else {
-    error = GRPC_ERROR_CREATE("Failed to initialize UV tcp handle");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Failed to initialize UV tcp handle");
     error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, uv_strerror(status));
+        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                           grpc_slice_from_static_string(uv_strerror(status)));
   }
 
   gpr_free(allocated_addr);
 
   if (error != GRPC_ERROR_NONE) {
-    grpc_error *error_out = GRPC_ERROR_CREATE_REFERENCING(
+    grpc_error *error_out = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
         "Failed to add port to server", &error, 1);
     GRPC_ERROR_UNREF(error);
     error = error_out;
diff --git a/src/core/lib/iomgr/tcp_server_windows.c b/src/core/lib/iomgr/tcp_server_windows.c
index bd4b9b2df1..12ce7d3fdd 100644
--- a/src/core/lib/iomgr/tcp_server_windows.c
+++ b/src/core/lib/iomgr/tcp_server_windows.c
@@ -122,8 +122,8 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
       } else {
         grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
-        return GRPC_ERROR_CREATE(GRPC_ARG_RESOURCE_QUOTA
-                                 " must be a pointer to a buffer pool");
+        return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+            GRPC_ARG_RESOURCE_QUOTA " must be a pointer to a buffer pool");
       }
     }
   }
@@ -248,9 +248,10 @@ failure:
   GPR_ASSERT(error != GRPC_ERROR_NONE);
   char *tgtaddr = grpc_sockaddr_to_uri(addr);
   grpc_error_set_int(
-      grpc_error_set_str(GRPC_ERROR_CREATE_REFERENCING(
+      grpc_error_set_str(GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                              "Failed to prepare server socket", &error, 1),
-                         GRPC_ERROR_STR_TARGET_ADDRESS, tgtaddr),
+                         GRPC_ERROR_STR_TARGET_ADDRESS,
+                         grpc_slice_from_copied_string(tgtaddr)),
       GRPC_ERROR_INT_FD, (intptr_t)sock);
   gpr_free(tgtaddr);
   GRPC_ERROR_UNREF(error);
@@ -533,7 +534,7 @@ done:
   gpr_free(allocated_addr);
 
   if (error != GRPC_ERROR_NONE) {
-    grpc_error *error_out = GRPC_ERROR_CREATE_REFERENCING(
+    grpc_error *error_out = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
         "Failed to add port to server", &error, 1);
     GRPC_ERROR_UNREF(error);
     error = error_out;
diff --git a/src/core/lib/iomgr/tcp_uv.c b/src/core/lib/iomgr/tcp_uv.c
index 5541c62068..8e8db9f7b4 100644
--- a/src/core/lib/iomgr/tcp_uv.c
+++ b/src/core/lib/iomgr/tcp_uv.c
@@ -152,7 +152,7 @@ static void read_callback(uv_stream_t *stream, ssize_t nread,
   // TODO(murgatroid99): figure out what the return value here means
   uv_read_stop(stream);
   if (nread == UV_EOF) {
-    error = GRPC_ERROR_CREATE("EOF");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("EOF");
   } else if (nread > 0) {
     // Successful read
     sub = grpc_slice_sub_no_ref(tcp->read_slice, 0, (size_t)nread);
@@ -173,7 +173,7 @@ static void read_callback(uv_stream_t *stream, ssize_t nread,
     }
   } else {
     // nread < 0: Error
-    error = GRPC_ERROR_CREATE("TCP Read failed");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("TCP Read failed");
   }
   grpc_closure_sched(&exec_ctx, cb, error);
   grpc_exec_ctx_finish(&exec_ctx);
@@ -193,9 +193,10 @@ static void uv_endpoint_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   status =
       uv_read_start((uv_stream_t *)tcp->handle, alloc_uv_buf, read_callback);
   if (status != 0) {
-    error = GRPC_ERROR_CREATE("TCP Read failed at start");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("TCP Read failed at start");
     error =
-        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, uv_strerror(status));
+        grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
+                           grpc_slice_from_static_string(uv_strerror(status)));
     grpc_closure_sched(exec_ctx, cb, error);
   }
   if (grpc_tcp_trace) {
@@ -214,7 +215,7 @@ static void write_callback(uv_write_t *req, int status) {
   if (status == 0) {
     error = GRPC_ERROR_NONE;
   } else {
-    error = GRPC_ERROR_CREATE("TCP Write failed");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("TCP Write failed");
   }
   if (grpc_tcp_trace) {
     const char *str = grpc_error_string(error);
@@ -249,8 +250,8 @@ static void uv_endpoint_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   }
 
   if (tcp->shutting_down) {
-    grpc_closure_sched(exec_ctx, cb,
-                       GRPC_ERROR_CREATE("TCP socket is shutting down"));
+    grpc_closure_sched(exec_ctx, cb, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                         "TCP socket is shutting down"));
     return;
   }
 
diff --git a/src/core/lib/iomgr/tcp_windows.c b/src/core/lib/iomgr/tcp_windows.c
index 6c413971e3..9134883226 100644
--- a/src/core/lib/iomgr/tcp_windows.c
+++ b/src/core/lib/iomgr/tcp_windows.c
@@ -175,7 +175,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *tcpp, grpc_error *error) {
   if (error == GRPC_ERROR_NONE) {
     if (info->wsa_error != 0 && !tcp->shutting_down) {
       char *utf8_message = gpr_format_message(info->wsa_error);
-      error = GRPC_ERROR_CREATE(utf8_message);
+      error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(utf8_message);
       gpr_free(utf8_message);
       grpc_slice_unref_internal(exec_ctx, tcp->read_slice);
     } else {
@@ -185,9 +185,9 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *tcpp, grpc_error *error) {
       } else {
         grpc_slice_unref_internal(exec_ctx, tcp->read_slice);
         error = tcp->shutting_down
-                    ? GRPC_ERROR_CREATE_REFERENCING("TCP stream shutting down",
-                                                    &tcp->shutdown_error, 1)
-                    : GRPC_ERROR_CREATE("End of TCP stream");
+                    ? GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                          "TCP stream shutting down", &tcp->shutdown_error, 1)
+                    : GRPC_ERROR_CREATE_FROM_STATIC_STRING("End of TCP stream");
       }
     }
   }
@@ -208,9 +208,10 @@ static void win_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   WSABUF buffer;
 
   if (tcp->shutting_down) {
-    grpc_closure_sched(exec_ctx, cb, GRPC_ERROR_CREATE_REFERENCING(
-                                         "TCP socket is shutting down",
-                                         &tcp->shutdown_error, 1));
+    grpc_closure_sched(
+        exec_ctx, cb,
+        GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+            "TCP socket is shutting down", &tcp->shutdown_error, 1));
     return;
   }
 
@@ -297,9 +298,10 @@ static void win_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   size_t len;
 
   if (tcp->shutting_down) {
-    grpc_closure_sched(exec_ctx, cb, GRPC_ERROR_CREATE_REFERENCING(
-                                         "TCP socket is shutting down",
-                                         &tcp->shutdown_error, 1));
+    grpc_closure_sched(
+        exec_ctx, cb,
+        GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+            "TCP socket is shutting down", &tcp->shutdown_error, 1));
     return;
   }
 
diff --git a/src/core/lib/iomgr/timer_generic.c b/src/core/lib/iomgr/timer_generic.c
index d4df96c214..e53c801929 100644
--- a/src/core/lib/iomgr/timer_generic.c
+++ b/src/core/lib/iomgr/timer_generic.c
@@ -109,8 +109,9 @@ void grpc_timer_list_init(gpr_timespec now) {
 
 void grpc_timer_list_shutdown(grpc_exec_ctx *exec_ctx) {
   int i;
-  run_some_expired_timers(exec_ctx, gpr_inf_future(g_clock_type), NULL,
-                          GRPC_ERROR_CREATE("Timer list shutdown"));
+  run_some_expired_timers(
+      exec_ctx, gpr_inf_future(g_clock_type), NULL,
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Timer list shutdown"));
   for (i = 0; i < NUM_SHARDS; i++) {
     shard_type *shard = &g_shards[i];
     gpr_mu_destroy(&shard->mu);
@@ -182,9 +183,9 @@ void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
 
   if (!g_initialized) {
     timer->pending = false;
-    grpc_closure_sched(
-        exec_ctx, timer->closure,
-        GRPC_ERROR_CREATE("Attempt to create timer before initialization"));
+    grpc_closure_sched(exec_ctx, timer->closure,
+                       GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                           "Attempt to create timer before initialization"));
     return;
   }
 
@@ -376,7 +377,7 @@ bool grpc_timer_check(grpc_exec_ctx *exec_ctx, gpr_timespec now,
       exec_ctx, now, next,
       gpr_time_cmp(now, gpr_inf_future(now.clock_type)) != 0
           ? GRPC_ERROR_NONE
-          : GRPC_ERROR_CREATE("Shutting down timer system"));
+          : GRPC_ERROR_CREATE_FROM_STATIC_STRING("Shutting down timer system"));
 }
 
 #endif /* GRPC_TIMER_USE_GENERIC */
diff --git a/src/core/lib/iomgr/timer_uv.c b/src/core/lib/iomgr/timer_uv.c
index f28a14405d..8e8a07578c 100644
--- a/src/core/lib/iomgr/timer_uv.c
+++ b/src/core/lib/iomgr/timer_uv.c
@@ -78,6 +78,10 @@ void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
   uv_timer->data = timer;
   timer->uv_timer = uv_timer;
   uv_timer_start(uv_timer, run_expired_timer, timeout, 0);
+  /* We assume that gRPC timers are only used alongside other active gRPC
+     objects, and that there will therefore always be something else keeping
+     the uv loop alive whenever there is a timer */
+  uv_unref((uv_handle_t *)uv_timer);
 }
 
 void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer) {
diff --git a/src/core/lib/iomgr/udp_server.c b/src/core/lib/iomgr/udp_server.c
index 71e295770a..60579e18ba 100644
--- a/src/core/lib/iomgr/udp_server.c
+++ b/src/core/lib/iomgr/udp_server.c
@@ -59,11 +59,13 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/sync.h>
 #include <grpc/support/time.h>
+#include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/sockaddr.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
+#include "src/core/lib/iomgr/socket_factory_posix.h"
 #include "src/core/lib/iomgr/socket_utils_posix.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
 #include "src/core/lib/support/string.h"
@@ -89,6 +91,9 @@ struct grpc_udp_listener {
 struct grpc_udp_server {
   gpr_mu mu;
 
+  /* factory to use for creating and binding sockets, or NULL */
+  grpc_socket_factory *socket_factory;
+
   /* active port count: how many ports are actually still listening */
   size_t active_ports;
   /* destroyed port count: how many ports are completely destroyed */
@@ -113,9 +118,24 @@ struct grpc_udp_server {
   void *user_data;
 };
 
-grpc_udp_server *grpc_udp_server_create(void) {
+static grpc_socket_factory *get_socket_factory(const grpc_channel_args *args) {
+  if (args) {
+    const grpc_arg *arg = grpc_channel_args_find(args, GRPC_ARG_SOCKET_FACTORY);
+    if (arg) {
+      GPR_ASSERT(arg->type == GRPC_ARG_POINTER);
+      return arg->value.pointer.p;
+    }
+  }
+  return NULL;
+}
+
+grpc_udp_server *grpc_udp_server_create(const grpc_channel_args *args) {
   grpc_udp_server *s = gpr_malloc(sizeof(grpc_udp_server));
   gpr_mu_init(&s->mu);
+  s->socket_factory = get_socket_factory(args);
+  if (s->socket_factory) {
+    grpc_socket_factory_ref(s->socket_factory);
+  }
   s->active_ports = 0;
   s->destroyed_ports = 0;
   s->shutdown = 0;
@@ -139,6 +159,10 @@ static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
     gpr_free(sp);
   }
 
+  if (s->socket_factory) {
+    grpc_socket_factory_unref(s->socket_factory);
+  }
+
   gpr_free(s);
 }
 
@@ -162,10 +186,7 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
   /* delete ALL the things */
   gpr_mu_lock(&s->mu);
 
-  if (!s->shutdown) {
-    gpr_mu_unlock(&s->mu);
-    return;
-  }
+  GPR_ASSERT(s->shutdown);
 
   if (s->head) {
     grpc_udp_listener *sp;
@@ -205,8 +226,8 @@ void grpc_udp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
     for (sp = s->head; sp; sp = sp->next) {
       GPR_ASSERT(sp->orphan_cb);
       sp->orphan_cb(exec_ctx, sp->emfd, sp->server->user_data);
-      grpc_fd_shutdown(exec_ctx, sp->emfd,
-                       GRPC_ERROR_CREATE("Server destroyed"));
+      grpc_fd_shutdown(exec_ctx, sp->emfd, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                               "Server destroyed"));
     }
     gpr_mu_unlock(&s->mu);
   } else {
@@ -215,8 +236,17 @@ void grpc_udp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
   }
 }
 
+static int bind_socket(grpc_socket_factory *socket_factory, int sockfd,
+                       const grpc_resolved_address *addr) {
+  return (socket_factory != NULL)
+             ? grpc_socket_factory_bind(socket_factory, sockfd, addr)
+             : bind(sockfd, (struct sockaddr *)addr->addr,
+                    (socklen_t)addr->len);
+}
+
 /* Prepare a recently-created socket for listening. */
-static int prepare_socket(int fd, const grpc_resolved_address *addr) {
+static int prepare_socket(grpc_socket_factory *socket_factory, int fd,
+                          const grpc_resolved_address *addr) {
   grpc_resolved_address sockname_temp;
   struct sockaddr *addr_ptr = (struct sockaddr *)addr->addr;
   /* Set send/receive socket buffers to 1 MB */
@@ -246,7 +276,7 @@ static int prepare_socket(int fd, const grpc_resolved_address *addr) {
   }
 
   GPR_ASSERT(addr->len < ~(socklen_t)0);
-  if (bind(fd, (struct sockaddr *)addr, (socklen_t)addr->len) < 0) {
+  if (bind_socket(socket_factory, fd, addr) < 0) {
     char *addr_str;
     grpc_sockaddr_to_string(&addr_str, addr, 0);
     gpr_log(GPR_ERROR, "bind addr=%s: %s", addr_str, strerror(errno));
@@ -288,7 +318,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
 
   gpr_mu_lock(&sp->server->mu);
   if (error != GRPC_ERROR_NONE) {
-    if (0 == --sp->server->active_ports) {
+    if (0 == --sp->server->active_ports && sp->server->shutdown) {
       gpr_mu_unlock(&sp->server->mu);
       deactivated_all_ports(exec_ctx, sp->server);
     } else {
@@ -311,7 +341,7 @@ static void on_write(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
 
   gpr_mu_lock(&(sp->server->mu));
   if (error != GRPC_ERROR_NONE) {
-    if (0 == --sp->server->active_ports) {
+    if (0 == --sp->server->active_ports && sp->server->shutdown) {
       gpr_mu_unlock(&sp->server->mu);
       deactivated_all_ports(exec_ctx, sp->server);
     } else {
@@ -339,7 +369,7 @@ static int add_socket_to_server(grpc_udp_server *s, int fd,
   char *addr_str;
   char *name;
 
-  port = prepare_socket(fd, addr);
+  port = prepare_socket(s->socket_factory, fd, addr);
   if (port >= 0) {
     grpc_sockaddr_to_string(&addr_str, addr, 1);
     gpr_asprintf(&name, "udp-server-listener:%s", addr_str);
@@ -417,8 +447,8 @@ int grpc_udp_server_add_port(grpc_udp_server *s,
     /* Try listening on IPv6 first. */
     addr = &wild6;
     // TODO(rjshade): Test and propagate the returned grpc_error*:
-    GRPC_ERROR_UNREF(grpc_create_dualstack_socket(addr, SOCK_DGRAM, IPPROTO_UDP,
-                                                  &dsmode, &fd));
+    GRPC_ERROR_UNREF(grpc_create_dualstack_socket_using_factory(
+        s->socket_factory, addr, SOCK_DGRAM, IPPROTO_UDP, &dsmode, &fd));
     allocated_port1 =
         add_socket_to_server(s, fd, addr, read_cb, write_cb, orphan_cb);
     if (fd >= 0 && dsmode == GRPC_DSMODE_DUALSTACK) {
@@ -433,8 +463,8 @@ int grpc_udp_server_add_port(grpc_udp_server *s,
   }
 
   // TODO(rjshade): Test and propagate the returned grpc_error*:
-  GRPC_ERROR_UNREF(grpc_create_dualstack_socket(addr, SOCK_DGRAM, IPPROTO_UDP,
-                                                &dsmode, &fd));
+  GRPC_ERROR_UNREF(grpc_create_dualstack_socket_using_factory(
+      s->socket_factory, addr, SOCK_DGRAM, IPPROTO_UDP, &dsmode, &fd));
   if (fd < 0) {
     gpr_log(GPR_ERROR, "Unable to create socket: %s", strerror(errno));
   }
diff --git a/src/core/lib/iomgr/udp_server.h b/src/core/lib/iomgr/udp_server.h
index 90842a47f0..9df3fe4d1f 100644
--- a/src/core/lib/iomgr/udp_server.h
+++ b/src/core/lib/iomgr/udp_server.h
@@ -58,7 +58,7 @@ typedef void (*grpc_udp_server_orphan_cb)(grpc_exec_ctx *exec_ctx,
                                           grpc_fd *emfd, void *user_data);
 
 /* Create a server, initially not bound to any ports */
-grpc_udp_server *grpc_udp_server_create(void);
+grpc_udp_server *grpc_udp_server_create(const grpc_channel_args *args);
 
 /* Start listening to bound ports. user_data is passed to callbacks. */
 void grpc_udp_server_start(grpc_exec_ctx *exec_ctx, grpc_udp_server *udp_server,
diff --git a/src/core/lib/iomgr/unix_sockets_posix.c b/src/core/lib/iomgr/unix_sockets_posix.c
index 1233cec04e..281865aece 100644
--- a/src/core/lib/iomgr/unix_sockets_posix.c
+++ b/src/core/lib/iomgr/unix_sockets_posix.c
@@ -60,7 +60,7 @@ grpc_error *grpc_resolve_unix_domain_address(const char *name,
     gpr_asprintf(&err_msg,
                  "Path name should not have more than %" PRIuPTR " characters.",
                  GPR_ARRAY_SIZE(un->sun_path) - 1);
-    err = GRPC_ERROR_CREATE(err_msg);
+    err = GRPC_ERROR_CREATE_FROM_COPIED_STRING(err_msg);
     gpr_free(err_msg);
     return err;
   }
diff --git a/src/core/lib/iomgr/unix_sockets_posix_noop.c b/src/core/lib/iomgr/unix_sockets_posix_noop.c
index 1daf5152c1..b9602cbf8b 100644
--- a/src/core/lib/iomgr/unix_sockets_posix_noop.c
+++ b/src/core/lib/iomgr/unix_sockets_posix_noop.c
@@ -47,7 +47,8 @@ void grpc_create_socketpair_if_unix(int sv[2]) {
 grpc_error *grpc_resolve_unix_domain_address(
     const char *name, grpc_resolved_addresses **addresses) {
   *addresses = NULL;
-  return GRPC_ERROR_CREATE("Unix domain sockets are not supported on Windows");
+  return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+      "Unix domain sockets are not supported on Windows");
 }
 
 int grpc_is_unix_socket(const grpc_resolved_address *addr) { return false; }
diff --git a/src/core/lib/profiling/basic_timers.c b/src/core/lib/profiling/basic_timers.c
index 1f1987fb8e..bc8e27714c 100644
--- a/src/core/lib/profiling/basic_timers.c
+++ b/src/core/lib/profiling/basic_timers.c
@@ -218,7 +218,7 @@ void gpr_timers_set_log_filename(const char *filename) {
 static void init_output() {
   gpr_thd_options options = gpr_thd_options_default();
   gpr_thd_options_set_joinable(&options);
-  gpr_thd_new(&g_writing_thread, writing_thread, NULL, &options);
+  GPR_ASSERT(gpr_thd_new(&g_writing_thread, writing_thread, NULL, &options));
   atexit(finish_writing);
 }
 
diff --git a/src/core/lib/security/credentials/google_default/google_default_credentials.c b/src/core/lib/security/credentials/google_default/google_default_credentials.c
index dd44621347..97501e6788 100644
--- a/src/core/lib/security/credentials/google_default/google_default_credentials.c
+++ b/src/core/lib/security/credentials/google_default/google_default_credentials.c
@@ -180,7 +180,7 @@ static grpc_error *create_default_creds_from_path(
   grpc_slice creds_data = grpc_empty_slice();
   grpc_error *error = GRPC_ERROR_NONE;
   if (creds_path == NULL) {
-    error = GRPC_ERROR_CREATE("creds_path unset");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("creds_path unset");
     goto end;
   }
   error = grpc_load_file(creds_path, 0, &creds_data);
@@ -190,10 +190,9 @@ static grpc_error *create_default_creds_from_path(
   json = grpc_json_parse_string_with_len(
       (char *)GRPC_SLICE_START_PTR(creds_data), GRPC_SLICE_LENGTH(creds_data));
   if (json == NULL) {
-    char *dump = grpc_dump_slice(creds_data, GPR_DUMP_HEX | GPR_DUMP_ASCII);
-    error = grpc_error_set_str(GRPC_ERROR_CREATE("Failed to parse JSON"),
-                               GRPC_ERROR_STR_RAW_BYTES, dump);
-    gpr_free(dump);
+    error = grpc_error_set_str(
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Failed to parse JSON"),
+        GRPC_ERROR_STR_RAW_BYTES, grpc_slice_ref_internal(creds_data));
     goto end;
   }
 
@@ -204,7 +203,7 @@ static grpc_error *create_default_creds_from_path(
         grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
             exec_ctx, key, grpc_max_auth_token_lifetime());
     if (result == NULL) {
-      error = GRPC_ERROR_CREATE(
+      error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
           "grpc_service_account_jwt_access_credentials_create_from_auth_json_"
           "key failed");
     }
@@ -217,7 +216,7 @@ static grpc_error *create_default_creds_from_path(
     result =
         grpc_refresh_token_credentials_create_from_auth_refresh_token(token);
     if (result == NULL) {
-      error = GRPC_ERROR_CREATE(
+      error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
           "grpc_refresh_token_credentials_create_from_auth_refresh_token "
           "failed");
     }
@@ -236,7 +235,8 @@ end:
 grpc_channel_credentials *grpc_google_default_credentials_create(void) {
   grpc_channel_credentials *result = NULL;
   grpc_call_credentials *call_creds = NULL;
-  grpc_error *error = GRPC_ERROR_CREATE("Failed to create Google credentials");
+  grpc_error *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+      "Failed to create Google credentials");
   grpc_error *err;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
 
@@ -274,7 +274,8 @@ grpc_channel_credentials *grpc_google_default_credentials_create(void) {
       call_creds = grpc_google_compute_engine_credentials_create(NULL);
       if (call_creds == NULL) {
         error = grpc_error_add_child(
-            error, GRPC_ERROR_CREATE("Failed to get credentials from network"));
+            error, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                       "Failed to get credentials from network"));
       }
     }
   }
diff --git a/src/core/lib/security/transport/client_auth_filter.c b/src/core/lib/security/transport/client_auth_filter.c
index 8dea1d98ff..8f321b9911 100644
--- a/src/core/lib/security/transport/client_auth_filter.c
+++ b/src/core/lib/security/transport/client_auth_filter.c
@@ -95,7 +95,8 @@ static void reset_auth_metadata_context(
 static void add_error(grpc_error **combined, grpc_error *error) {
   if (error == GRPC_ERROR_NONE) return;
   if (*combined == GRPC_ERROR_NONE) {
-    *combined = GRPC_ERROR_CREATE("Client auth metadata plugin error");
+    *combined = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Client auth metadata plugin error");
   }
   *combined = grpc_error_add_child(*combined, error);
 }
@@ -114,9 +115,10 @@ static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
   grpc_error *error = GRPC_ERROR_NONE;
   if (status != GRPC_CREDENTIALS_OK) {
     error = grpc_error_set_int(
-        GRPC_ERROR_CREATE(error_details != NULL && strlen(error_details) > 0
-                              ? error_details
-                              : "Credentials failed to get metadata."),
+        GRPC_ERROR_CREATE_FROM_COPIED_STRING(
+            error_details != NULL && strlen(error_details) > 0
+                ? error_details
+                : "Credentials failed to get metadata."),
         GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAUTHENTICATED);
   } else {
     GPR_ASSERT(num_md <= MAX_CREDENTIALS_METADATA_COUNT);
@@ -192,7 +194,7 @@ static void send_security_metadata(grpc_exec_ctx *exec_ctx,
       grpc_transport_stream_op_finish_with_failure(
           exec_ctx, op,
           grpc_error_set_int(
-              GRPC_ERROR_CREATE(
+              GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                   "Incompatible credentials set on channel and call."),
               GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAUTHENTICATED));
       return;
@@ -225,9 +227,10 @@ static void on_host_checked(grpc_exec_ctx *exec_ctx, void *user_data,
                  host);
     gpr_free(host);
     grpc_call_element_signal_error(
-        exec_ctx, elem, grpc_error_set_int(GRPC_ERROR_CREATE(error_msg),
-                                           GRPC_ERROR_INT_GRPC_STATUS,
-                                           GRPC_STATUS_UNAUTHENTICATED));
+        exec_ctx, elem,
+        grpc_error_set_int(GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_msg),
+                           GRPC_ERROR_INT_GRPC_STATUS,
+                           GRPC_STATUS_UNAUTHENTICATED));
     gpr_free(error_msg);
   }
 }
diff --git a/src/core/lib/security/transport/secure_endpoint.c b/src/core/lib/security/transport/secure_endpoint.c
index 7d58843d69..568d70fa38 100644
--- a/src/core/lib/security/transport/secure_endpoint.c
+++ b/src/core/lib/security/transport/secure_endpoint.c
@@ -162,7 +162,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *user_data,
 
   if (error != GRPC_ERROR_NONE) {
     grpc_slice_buffer_reset_and_unref_internal(exec_ctx, ep->read_buffer);
-    call_read_cb(exec_ctx, ep, GRPC_ERROR_CREATE_REFERENCING(
+    call_read_cb(exec_ctx, ep, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                                    "Secure read failed", &error, 1));
     return;
   }
@@ -220,8 +220,10 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *user_data,
 
   if (result != TSI_OK) {
     grpc_slice_buffer_reset_and_unref_internal(exec_ctx, ep->read_buffer);
-    call_read_cb(exec_ctx, ep, grpc_set_tsi_error_result(
-                                   GRPC_ERROR_CREATE("Unwrap failed"), result));
+    call_read_cb(
+        exec_ctx, ep,
+        grpc_set_tsi_error_result(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Unwrap failed"), result));
     return;
   }
 
@@ -332,7 +334,8 @@ static void endpoint_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *secure_ep,
     grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &ep->output_buffer);
     grpc_closure_sched(
         exec_ctx, cb,
-        grpc_set_tsi_error_result(GRPC_ERROR_CREATE("Wrap failed"), result));
+        grpc_set_tsi_error_result(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Wrap failed"), result));
     GPR_TIMER_END("secure_endpoint.endpoint_write", 0);
     return;
   }
diff --git a/src/core/lib/security/transport/security_connector.c b/src/core/lib/security/transport/security_connector.c
index ad083a730f..b0cbc83639 100644
--- a/src/core/lib/security/transport/security_connector.c
+++ b/src/core/lib/security/transport/security_connector.c
@@ -137,9 +137,9 @@ void grpc_security_connector_check_peer(grpc_exec_ctx *exec_ctx,
                                         grpc_auth_context **auth_context,
                                         grpc_closure *on_peer_checked) {
   if (sc == NULL) {
-    grpc_closure_sched(
-        exec_ctx, on_peer_checked,
-        GRPC_ERROR_CREATE("cannot check peer -- no security connector"));
+    grpc_closure_sched(exec_ctx, on_peer_checked,
+                       GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                           "cannot check peer -- no security connector"));
     tsi_peer_destruct(&peer);
   } else {
     sc->vtable->check_peer(exec_ctx, sc, peer, auth_context, on_peer_checked);
@@ -330,7 +330,8 @@ static void fake_check_peer(grpc_exec_ctx *exec_ctx,
   grpc_error *error = GRPC_ERROR_NONE;
   *auth_context = NULL;
   if (peer.property_count != 1) {
-    error = GRPC_ERROR_CREATE("Fake peers should only have 1 property.");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Fake peers should only have 1 property.");
     goto end;
   }
   prop_name = peer.properties[0].name;
@@ -339,13 +340,14 @@ static void fake_check_peer(grpc_exec_ctx *exec_ctx,
     char *msg;
     gpr_asprintf(&msg, "Unexpected property in fake peer: %s.",
                  prop_name == NULL ? "<EMPTY>" : prop_name);
-    error = GRPC_ERROR_CREATE(msg);
+    error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
     gpr_free(msg);
     goto end;
   }
   if (strncmp(peer.properties[0].value.data, TSI_FAKE_CERTIFICATE_TYPE,
               peer.properties[0].value.length)) {
-    error = GRPC_ERROR_CREATE("Invalid value for cert type property.");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Invalid value for cert type property.");
     goto end;
   }
   *auth_context = grpc_auth_context_create(NULL);
@@ -586,18 +588,19 @@ static grpc_error *ssl_check_peer(grpc_security_connector *sc,
   const tsi_peer_property *p =
       tsi_peer_get_property_by_name(peer, TSI_SSL_ALPN_SELECTED_PROTOCOL);
   if (p == NULL) {
-    return GRPC_ERROR_CREATE(
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
         "Cannot check peer: missing selected ALPN property.");
   }
   if (!grpc_chttp2_is_alpn_version_supported(p->value.data, p->value.length)) {
-    return GRPC_ERROR_CREATE("Cannot check peer: invalid ALPN value.");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Cannot check peer: invalid ALPN value.");
   }
 
   /* Check the peer name if specified. */
   if (peer_name != NULL && !ssl_host_matches_name(peer, peer_name)) {
     char *msg;
     gpr_asprintf(&msg, "Peer name %s is not in peer certificate", peer_name);
-    grpc_error *error = GRPC_ERROR_CREATE(msg);
+    grpc_error *error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
     gpr_free(msg);
     return error;
   }
diff --git a/src/core/lib/security/transport/security_handshaker.c b/src/core/lib/security/transport/security_handshaker.c
index 7065d261ba..2f39327670 100644
--- a/src/core/lib/security/transport/security_handshaker.c
+++ b/src/core/lib/security/transport/security_handshaker.c
@@ -120,7 +120,7 @@ static void security_handshake_failed_locked(grpc_exec_ctx *exec_ctx,
   if (error == GRPC_ERROR_NONE) {
     // If we were shut down after the handshake succeeded but before an
     // endpoint callback was invoked, we need to generate our own error.
-    error = GRPC_ERROR_CREATE("Handshaker shutdown");
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Handshaker shutdown");
   }
   const char *msg = grpc_error_string(error);
   gpr_log(GPR_DEBUG, "Security handshake failed: %s", msg);
@@ -156,7 +156,8 @@ static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *arg,
       tsi_handshaker_create_frame_protector(h->handshaker, NULL, &protector);
   if (result != TSI_OK) {
     error = grpc_set_tsi_error_result(
-        GRPC_ERROR_CREATE("Frame protector creation failed"), result);
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Frame protector creation failed"),
+        result);
     security_handshake_failed_locked(exec_ctx, h, error);
     goto done;
   }
@@ -191,7 +192,7 @@ static grpc_error *check_peer_locked(grpc_exec_ctx *exec_ctx,
   tsi_result result = tsi_handshaker_extract_peer(h->handshaker, &peer);
   if (result != TSI_OK) {
     return grpc_set_tsi_error_result(
-        GRPC_ERROR_CREATE("Peer extraction failed"), result);
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Peer extraction failed"), result);
   }
   grpc_security_connector_check_peer(exec_ctx, h->connector, peer,
                                      &h->auth_context, &h->on_peer_checked);
@@ -215,8 +216,8 @@ static grpc_error *send_handshake_bytes_to_peer_locked(grpc_exec_ctx *exec_ctx,
     }
   } while (result == TSI_INCOMPLETE_DATA);
   if (result != TSI_OK) {
-    return grpc_set_tsi_error_result(GRPC_ERROR_CREATE("Handshake failed"),
-                                     result);
+    return grpc_set_tsi_error_result(
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Handshake failed"), result);
   }
   // Send data.
   grpc_slice to_send =
@@ -234,8 +235,8 @@ static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
   gpr_mu_lock(&h->mu);
   if (error != GRPC_ERROR_NONE || h->shutdown) {
     security_handshake_failed_locked(
-        exec_ctx, h,
-        GRPC_ERROR_CREATE_REFERENCING("Handshake read failed", &error, 1));
+        exec_ctx, h, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                         "Handshake read failed", &error, 1));
     gpr_mu_unlock(&h->mu);
     security_handshaker_unref(exec_ctx, h);
     return;
@@ -270,8 +271,9 @@ static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
   }
   if (result != TSI_OK) {
     security_handshake_failed_locked(
-        exec_ctx, h, grpc_set_tsi_error_result(
-                         GRPC_ERROR_CREATE("Handshake failed"), result));
+        exec_ctx, h,
+        grpc_set_tsi_error_result(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Handshake failed"), result));
     gpr_mu_unlock(&h->mu);
     security_handshaker_unref(exec_ctx, h);
     return;
@@ -314,8 +316,8 @@ static void on_handshake_data_sent_to_peer(grpc_exec_ctx *exec_ctx, void *arg,
   gpr_mu_lock(&h->mu);
   if (error != GRPC_ERROR_NONE || h->shutdown) {
     security_handshake_failed_locked(
-        exec_ctx, h,
-        GRPC_ERROR_CREATE_REFERENCING("Handshake write failed", &error, 1));
+        exec_ctx, h, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                         "Handshake write failed", &error, 1));
     gpr_mu_unlock(&h->mu);
     security_handshaker_unref(exec_ctx, h);
     return;
@@ -429,7 +431,8 @@ static void fail_handshaker_do_handshake(grpc_exec_ctx *exec_ctx,
                                          grpc_closure *on_handshake_done,
                                          grpc_handshaker_args *args) {
   grpc_closure_sched(exec_ctx, on_handshake_done,
-                     GRPC_ERROR_CREATE("Failed to create security handshaker"));
+                     GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                         "Failed to create security handshaker"));
 }
 
 static const grpc_handshaker_vtable fail_handshaker_vtable = {
diff --git a/src/core/lib/security/transport/server_auth_filter.c b/src/core/lib/security/transport/server_auth_filter.c
index 01cb473177..3cf0632220 100644
--- a/src/core/lib/security/transport/server_auth_filter.c
+++ b/src/core/lib/security/transport/server_auth_filter.c
@@ -144,9 +144,10 @@ static void on_md_processing_done(
       calld->transport_op->send_message = NULL;
     }
     calld->transport_op->send_trailing_metadata = NULL;
-    grpc_closure_sched(&exec_ctx, calld->on_done_recv,
-                       grpc_error_set_int(GRPC_ERROR_CREATE(error_details),
-                                          GRPC_ERROR_INT_GRPC_STATUS, status));
+    grpc_closure_sched(
+        &exec_ctx, calld->on_done_recv,
+        grpc_error_set_int(GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_details),
+                           GRPC_ERROR_INT_GRPC_STATUS, status));
   }
 
   grpc_exec_ctx_finish(&exec_ctx);
@@ -158,7 +159,7 @@ static void auth_on_recv(grpc_exec_ctx *exec_ctx, void *user_data,
   call_data *calld = elem->call_data;
   channel_data *chand = elem->channel_data;
   if (error == GRPC_ERROR_NONE) {
-    if (chand->creds->processor.process != NULL) {
+    if (chand->creds != NULL && chand->creds->processor.process != NULL) {
       calld->md = metadata_batch_to_md_array(calld->recv_initial_metadata);
       chand->creds->processor.process(
           chand->creds->processor.state, calld->auth_context,
@@ -242,7 +243,6 @@ static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
 
   GPR_ASSERT(!args->is_last);
   GPR_ASSERT(auth_context != NULL);
-  GPR_ASSERT(creds != NULL);
 
   /* initialize members */
   chand->auth_context =
diff --git a/src/core/lib/security/transport/tsi_error.c b/src/core/lib/security/transport/tsi_error.c
index afc1733567..eae0a676b0 100644
--- a/src/core/lib/security/transport/tsi_error.c
+++ b/src/core/lib/security/transport/tsi_error.c
@@ -34,7 +34,9 @@
 #include "src/core/lib/security/transport/tsi_error.h"
 
 grpc_error *grpc_set_tsi_error_result(grpc_error *error, tsi_result result) {
-  return grpc_error_set_int(grpc_error_set_str(error, GRPC_ERROR_STR_TSI_ERROR,
-                                               tsi_result_to_string(result)),
-                            GRPC_ERROR_INT_TSI_CODE, result);
+  return grpc_error_set_int(
+      grpc_error_set_str(
+          error, GRPC_ERROR_STR_TSI_ERROR,
+          grpc_slice_from_static_string(tsi_result_to_string(result))),
+      GRPC_ERROR_INT_TSI_CODE, result);
 }
diff --git a/src/core/lib/security/util/b64.c b/src/core/lib/security/util/b64.c
index 09c8213131..0d5a917660 100644
--- a/src/core/lib/security/util/b64.c
+++ b/src/core/lib/security/util/b64.c
@@ -71,15 +71,31 @@ static const char base64_url_safe_chars[] =
 
 char *grpc_base64_encode(const void *vdata, size_t data_size, int url_safe,
                          int multiline) {
-  const unsigned char *data = vdata;
-  const char *base64_chars =
-      url_safe ? base64_url_safe_chars : base64_url_unsafe_chars;
+  size_t result_projected_size =
+      grpc_base64_estimate_encoded_size(data_size, url_safe, multiline);
+  char *result = gpr_malloc(result_projected_size);
+  grpc_base64_encode_core(result, vdata, data_size, url_safe, multiline);
+  return result;
+}
+
+size_t grpc_base64_estimate_encoded_size(size_t data_size, int url_safe,
+                                         int multiline) {
   size_t result_projected_size =
       4 * ((data_size + 3) / 3) +
       2 * (multiline ? (data_size / (3 * GRPC_BASE64_MULTILINE_NUM_BLOCKS))
                      : 0) +
       1;
-  char *result = gpr_malloc(result_projected_size);
+  return result_projected_size;
+}
+
+void grpc_base64_encode_core(char *result, const void *vdata, size_t data_size,
+                             int url_safe, int multiline) {
+  const unsigned char *data = vdata;
+  const char *base64_chars =
+      url_safe ? base64_url_safe_chars : base64_url_unsafe_chars;
+  const size_t result_projected_size =
+      grpc_base64_estimate_encoded_size(data_size, url_safe, multiline);
+
   char *current = result;
   size_t num_blocks = 0;
   size_t i = 0;
@@ -119,7 +135,6 @@ char *grpc_base64_encode(const void *vdata, size_t data_size, int url_safe,
   GPR_ASSERT(current >= result);
   GPR_ASSERT((uintptr_t)(current - result) < result_projected_size);
   result[current - result] = '\0';
-  return result;
 }
 
 grpc_slice grpc_base64_decode(grpc_exec_ctx *exec_ctx, const char *b64,
diff --git a/src/core/lib/security/util/b64.h b/src/core/lib/security/util/b64.h
index d42a136f61..ef52291c6a 100644
--- a/src/core/lib/security/util/b64.h
+++ b/src/core/lib/security/util/b64.h
@@ -37,10 +37,22 @@
 #include <grpc/slice.h>
 
 /* Encodes data using base64. It is the caller's responsability to free
-   the returned char * using gpr_free. Returns NULL on NULL input. */
+   the returned char * using gpr_free. Returns NULL on NULL input.
+   TODO(makdharma) : change the flags to bool from int */
 char *grpc_base64_encode(const void *data, size_t data_size, int url_safe,
                          int multiline);
 
+/* estimate the upper bound on size of base64 encoded data. The actual size
+ * is guaranteed to be less than or equal to the size returned here. */
+size_t grpc_base64_estimate_encoded_size(size_t data_size, int url_safe,
+                                         int multiline);
+
+/* Encodes data using base64 and write it to memory pointed to by result. It is
+ * the caller's responsiblity to allocate enough memory in |result| to fit the
+ * encoded data. */
+void grpc_base64_encode_core(char *result, const void *vdata, size_t data_size,
+                             int url_safe, int multiline);
+
 /* Decodes data according to the base64 specification. Returns an empty
    slice in case of failure. */
 grpc_slice grpc_base64_decode(grpc_exec_ctx *exec_ctx, const char *b64,
diff --git a/src/core/lib/support/atm.c b/src/core/lib/support/atm.c
new file mode 100644
index 0000000000..06e8432caf
--- /dev/null
+++ b/src/core/lib/support/atm.c
@@ -0,0 +1,47 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/atm.h>
+#include <grpc/support/useful.h>
+
+gpr_atm gpr_atm_no_barrier_clamped_add(gpr_atm *value, gpr_atm delta,
+                                       gpr_atm min, gpr_atm max) {
+  gpr_atm current;
+  gpr_atm new;
+  do {
+    current = gpr_atm_no_barrier_load(value);
+    new = GPR_CLAMP(current + delta, min, max);
+    if (new == current) break;
+  } while (!gpr_atm_no_barrier_cas(value, current, new));
+  return new;
+}
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index 2c5d8c0ff3..9342c5f8e9 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -264,7 +264,7 @@ static void add_batch_error(grpc_exec_ctx *exec_ctx, batch_control *bctl,
 static void add_init_error(grpc_error **composite, grpc_error *new) {
   if (new == GRPC_ERROR_NONE) return;
   if (*composite == GRPC_ERROR_NONE)
-    *composite = GRPC_ERROR_CREATE("Call creation failed");
+    *composite = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Call creation failed");
   *composite = grpc_error_add_child(*composite, new);
 }
 
@@ -335,17 +335,17 @@ grpc_error *grpc_call_create(grpc_exec_ctx *exec_ctx,
      * call. */
     if (args->propagation_mask & GRPC_PROPAGATE_CENSUS_TRACING_CONTEXT) {
       if (0 == (args->propagation_mask & GRPC_PROPAGATE_CENSUS_STATS_CONTEXT)) {
-        add_init_error(&error,
-                       GRPC_ERROR_CREATE("Census tracing propagation requested "
-                                         "without Census context propagation"));
+        add_init_error(&error, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                   "Census tracing propagation requested "
+                                   "without Census context propagation"));
       }
       grpc_call_context_set(
           call, GRPC_CONTEXT_TRACING,
           args->parent_call->context[GRPC_CONTEXT_TRACING].value, NULL);
     } else if (args->propagation_mask & GRPC_PROPAGATE_CENSUS_STATS_CONTEXT) {
-      add_init_error(&error,
-                     GRPC_ERROR_CREATE("Census context propagation requested "
-                                       "without Census tracing propagation"));
+      add_init_error(&error, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                 "Census context propagation requested "
+                                 "without Census tracing propagation"));
     }
     if (args->propagation_mask & GRPC_PROPAGATE_CANCELLATION) {
       call->cancellation_is_inherited = 1;
@@ -603,8 +603,9 @@ static void cancel_with_error(grpc_exec_ctx *exec_ctx, grpc_call *c,
 static grpc_error *error_from_status(grpc_status_code status,
                                      const char *description) {
   return grpc_error_set_int(
-      grpc_error_set_str(GRPC_ERROR_CREATE(description),
-                         GRPC_ERROR_STR_GRPC_MESSAGE, description),
+      grpc_error_set_str(GRPC_ERROR_CREATE_FROM_COPIED_STRING(description),
+                         GRPC_ERROR_STR_GRPC_MESSAGE,
+                         grpc_slice_from_copied_string(description)),
       GRPC_ERROR_INT_GRPC_STATUS, status);
 }
 
@@ -624,16 +625,15 @@ static bool get_final_status_from(
     void (*set_value)(grpc_status_code code, void *user_data),
     void *set_value_user_data, grpc_slice *details) {
   grpc_status_code code;
-  const char *msg = NULL;
-  grpc_error_get_status(error, call->send_deadline, &code, &msg, NULL);
+  grpc_slice slice = grpc_empty_slice();
+  grpc_error_get_status(error, call->send_deadline, &code, &slice, NULL);
   if (code == GRPC_STATUS_OK && !allow_ok_status) {
     return false;
   }
 
   set_value(code, set_value_user_data);
   if (details != NULL) {
-    *details =
-        msg == NULL ? grpc_empty_slice() : grpc_slice_from_copied_string(msg);
+    *details = grpc_slice_ref_internal(slice);
   }
   return true;
 }
@@ -896,18 +896,19 @@ static void recv_common_filter(grpc_exec_ctx *exec_ctx, grpc_call *call,
     grpc_error *error =
         status_code == GRPC_STATUS_OK
             ? GRPC_ERROR_NONE
-            : grpc_error_set_int(GRPC_ERROR_CREATE("Error received from peer"),
+            : grpc_error_set_int(GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                     "Error received from peer"),
                                  GRPC_ERROR_INT_GRPC_STATUS,
                                  (intptr_t)status_code);
 
     if (b->idx.named.grpc_message != NULL) {
-      char *msg =
-          grpc_slice_to_c_string(GRPC_MDVALUE(b->idx.named.grpc_message->md));
-      error = grpc_error_set_str(error, GRPC_ERROR_STR_GRPC_MESSAGE, msg);
-      gpr_free(msg);
+      error = grpc_error_set_str(
+          error, GRPC_ERROR_STR_GRPC_MESSAGE,
+          grpc_slice_ref_internal(GRPC_MDVALUE(b->idx.named.grpc_message->md)));
       grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.grpc_message);
     } else if (error != GRPC_ERROR_NONE) {
-      error = grpc_error_set_str(error, GRPC_ERROR_STR_GRPC_MESSAGE, "");
+      error = grpc_error_set_str(error, GRPC_ERROR_STR_GRPC_MESSAGE,
+                                 grpc_empty_slice());
     }
 
     set_status_from_error(exec_ctx, call, STATUS_FROM_WIRE, error);
@@ -1056,8 +1057,8 @@ static grpc_error *consolidate_batch_errors(batch_control *bctl) {
     bctl->errors[0] = NULL;
     return e;
   } else {
-    grpc_error *error =
-        GRPC_ERROR_CREATE_REFERENCING("Call batch failed", bctl->errors, n);
+    grpc_error *error = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+        "Call batch failed", bctl->errors, n);
     for (size_t i = 0; i < n; i++) {
       GRPC_ERROR_UNREF(bctl->errors[i]);
       bctl->errors[i] = NULL;
@@ -1521,7 +1522,8 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         {
           grpc_error *override_error = GRPC_ERROR_NONE;
           if (op->data.send_status_from_server.status != GRPC_STATUS_OK) {
-            override_error = GRPC_ERROR_CREATE("Error from server send status");
+            override_error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                "Error from server send status");
           }
           if (op->data.send_status_from_server.status_details != NULL) {
             call->send_extra_metadata[1].md = grpc_mdelem_from_slices(
@@ -1531,8 +1533,9 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
             call->send_extra_metadata_count++;
             char *msg = grpc_slice_to_c_string(
                 GRPC_MDVALUE(call->send_extra_metadata[1].md));
-            override_error = grpc_error_set_str(
-                override_error, GRPC_ERROR_STR_GRPC_MESSAGE, msg);
+            override_error =
+                grpc_error_set_str(override_error, GRPC_ERROR_STR_GRPC_MESSAGE,
+                                   grpc_slice_from_copied_string(msg));
             gpr_free(msg);
           }
           set_status_from_error(exec_ctx, call, STATUS_FROM_API_OVERRIDE,
diff --git a/src/core/lib/surface/channel.c b/src/core/lib/surface/channel.c
index 2b700b2f67..b4bfb92042 100644
--- a/src/core/lib/surface/channel.c
+++ b/src/core/lib/surface/channel.c
@@ -85,19 +85,10 @@ struct grpc_channel {
 static void destroy_channel(grpc_exec_ctx *exec_ctx, void *arg,
                             grpc_error *error);
 
-grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
-                                  const grpc_channel_args *input_args,
-                                  grpc_channel_stack_type channel_stack_type,
-                                  grpc_transport *optional_transport) {
-  grpc_channel_stack_builder *builder = grpc_channel_stack_builder_create();
-  grpc_channel_stack_builder_set_channel_arguments(exec_ctx, builder,
-                                                   input_args);
-  grpc_channel_stack_builder_set_target(builder, target);
-  grpc_channel_stack_builder_set_transport(builder, optional_transport);
-  if (!grpc_channel_init_create_stack(exec_ctx, builder, channel_stack_type)) {
-    grpc_channel_stack_builder_destroy(exec_ctx, builder);
-    return NULL;
-  }
+grpc_channel *grpc_channel_create_with_builder(
+    grpc_exec_ctx *exec_ctx, grpc_channel_stack_builder *builder,
+    grpc_channel_stack_type channel_stack_type) {
+  char *target = gpr_strdup(grpc_channel_stack_builder_get_target(builder));
   grpc_channel_args *args = grpc_channel_args_copy(
       grpc_channel_stack_builder_get_channel_arguments(builder));
   grpc_channel *channel;
@@ -108,11 +99,12 @@ grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
     gpr_log(GPR_ERROR, "channel stack builder failed: %s",
             grpc_error_string(error));
     GRPC_ERROR_UNREF(error);
+    gpr_free(target);
     goto done;
   }
 
   memset(channel, 0, sizeof(*channel));
-  channel->target = gpr_strdup(target);
+  channel->target = target;
   channel->is_client = grpc_channel_stack_type_is_client(channel_stack_type);
   gpr_mu_init(&channel->registered_call_mu);
   channel->registered_calls = NULL;
@@ -183,10 +175,33 @@ done:
   return channel;
 }
 
+grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
+                                  const grpc_channel_args *input_args,
+                                  grpc_channel_stack_type channel_stack_type,
+                                  grpc_transport *optional_transport) {
+  grpc_channel_stack_builder *builder = grpc_channel_stack_builder_create();
+  grpc_channel_stack_builder_set_channel_arguments(exec_ctx, builder,
+                                                   input_args);
+  grpc_channel_stack_builder_set_target(builder, target);
+  grpc_channel_stack_builder_set_transport(builder, optional_transport);
+  if (!grpc_channel_init_create_stack(exec_ctx, builder, channel_stack_type)) {
+    grpc_channel_stack_builder_destroy(exec_ctx, builder);
+    return NULL;
+  }
+  return grpc_channel_create_with_builder(exec_ctx, builder,
+                                          channel_stack_type);
+}
+
 size_t grpc_channel_get_call_size_estimate(grpc_channel *channel) {
 #define ROUND_UP_SIZE 256
+  /* We round up our current estimate to the NEXT value of ROUND_UP_SIZE.
+     This ensures:
+      1. a consistent size allocation when our estimate is drifting slowly
+         (which is common) - which tends to help most allocators reuse memory
+      2. a small amount of allowed growth over the estimate without hitting
+         the arena size doubling case, reducing overall memory usage */
   return ((size_t)gpr_atm_no_barrier_load(&channel->call_size_estimate) +
-          ROUND_UP_SIZE) &
+          2 * ROUND_UP_SIZE) &
          ~(size_t)(ROUND_UP_SIZE - 1);
 }
 
@@ -380,7 +395,8 @@ void grpc_channel_destroy(grpc_channel *channel) {
   grpc_channel_element *elem;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   GRPC_API_TRACE("grpc_channel_destroy(channel=%p)", 1, (channel));
-  op->disconnect_with_error = GRPC_ERROR_CREATE("Channel Destroyed");
+  op->disconnect_with_error =
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Destroyed");
   elem = grpc_channel_stack_element(CHANNEL_STACK_FROM_CHANNEL(channel), 0);
   elem->filter->start_transport_op(&exec_ctx, elem, op);
 
diff --git a/src/core/lib/surface/channel.h b/src/core/lib/surface/channel.h
index c4aebd8b9b..0f203a3e59 100644
--- a/src/core/lib/surface/channel.h
+++ b/src/core/lib/surface/channel.h
@@ -35,6 +35,7 @@
 #define GRPC_CORE_LIB_SURFACE_CHANNEL_H
 
 #include "src/core/lib/channel/channel_stack.h"
+#include "src/core/lib/channel/channel_stack_builder.h"
 #include "src/core/lib/surface/channel_stack_type.h"
 
 grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
@@ -42,6 +43,10 @@ grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
                                   grpc_channel_stack_type channel_stack_type,
                                   grpc_transport *optional_transport);
 
+grpc_channel *grpc_channel_create_with_builder(
+    grpc_exec_ctx *exec_ctx, grpc_channel_stack_builder *builder,
+    grpc_channel_stack_type channel_stack_type);
+
 /** Create a call given a grpc_channel, in order to call \a method.
     Progress is tied to activity on \a pollset_set. The returned call object is
     meant to be used with \a grpc_call_start_batch_and_execute, which relies on
diff --git a/src/core/lib/surface/completion_queue_factory.c b/src/core/lib/surface/completion_queue_factory.c
new file mode 100644
index 0000000000..db67a5192b
--- /dev/null
+++ b/src/core/lib/surface/completion_queue_factory.c
@@ -0,0 +1,77 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/surface/completion_queue_factory.h"
+#include "src/core/lib/surface/completion_queue.h"
+
+#include <grpc/support/log.h>
+
+/* TODO (sreek) - Currently this does not use the attributes arg. This will be
+   added in a future PR */
+static grpc_completion_queue* default_create(
+    const grpc_completion_queue_factory* factory,
+    const grpc_completion_queue_attributes* attributes) {
+  return grpc_completion_queue_create(NULL);
+}
+
+static grpc_completion_queue_factory_vtable default_vtable = {default_create};
+
+static const grpc_completion_queue_factory g_default_cq_factory = {
+    "Default Factory", NULL, &default_vtable};
+
+const grpc_completion_queue_factory* grpc_completion_queue_factory_lookup(
+    const grpc_completion_queue_attributes* attributes) {
+  /* As we add more fields to grpc_completion_queue_attributes, we may have to
+     change this assert to:
+         GPR_ASSERT (attributes->version >= 1 &&
+             attributes->version <= GRPC_CQ_CURRENT_VERSION) */
+  GPR_ASSERT(attributes->version == 1);
+
+  /* The default factory can handle version 1 of the attributes structure. We
+     may have to change this as more fields are added to the structure */
+  return &g_default_cq_factory;
+}
+
+grpc_completion_queue* grpc_completion_queue_create_for_next(void* reserved) {
+  GPR_ASSERT(!reserved);
+  grpc_completion_queue_attributes attr = {1, GRPC_CQ_NEXT,
+                                           GRPC_CQ_DEFAULT_POLLING};
+  return g_default_cq_factory.vtable->create(&g_default_cq_factory, &attr);
+}
+
+grpc_completion_queue* grpc_completion_queue_create_for_pluck(void* reserved) {
+  GPR_ASSERT(!reserved);
+  grpc_completion_queue_attributes attr = {1, GRPC_CQ_PLUCK,
+                                           GRPC_CQ_DEFAULT_POLLING};
+  return g_default_cq_factory.vtable->create(&g_default_cq_factory, &attr);
+}
diff --git a/src/core/lib/surface/completion_queue_factory.h b/src/core/lib/surface/completion_queue_factory.h
new file mode 100644
index 0000000000..57e90b5090
--- /dev/null
+++ b/src/core/lib/surface/completion_queue_factory.h
@@ -0,0 +1,51 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SURFACE_COMPLETION_QUEUE_FACTORY_H
+#define GRPC_CORE_LIB_SURFACE_COMPLETION_QUEUE_FACTORY_H
+
+#include <grpc/grpc.h>
+#include "src/core/lib/surface/completion_queue.h"
+
+typedef struct grpc_completion_queue_factory_vtable {
+  grpc_completion_queue* (*create)(const grpc_completion_queue_factory*,
+                                   const grpc_completion_queue_attributes*);
+} grpc_completion_queue_factory_vtable;
+
+struct grpc_completion_queue_factory {
+  const char* name;
+  void* data; /* Factory specific data */
+  grpc_completion_queue_factory_vtable* vtable;
+};
+
+#endif /* GRPC_CORE_LIB_SURFACE_COMPLETION_QUEUE_FACTORY_H */
diff --git a/src/core/lib/surface/lame_client.c b/src/core/lib/surface/lame_client.c
index 9ddb88bd11..0c408aa288 100644
--- a/src/core/lib/surface/lame_client.c
+++ b/src/core/lib/surface/lame_client.c
@@ -90,7 +90,8 @@ static void lame_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
     fill_metadata(exec_ctx, elem, op->recv_trailing_metadata);
   }
   grpc_transport_stream_op_finish_with_failure(
-      exec_ctx, op, GRPC_ERROR_CREATE("lame client channel"));
+      exec_ctx, op,
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("lame client channel"));
 }
 
 static char *lame_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
@@ -111,8 +112,9 @@ static void lame_start_transport_op(grpc_exec_ctx *exec_ctx,
                        GRPC_ERROR_NONE);
   }
   if (op->send_ping != NULL) {
-    grpc_closure_sched(exec_ctx, op->send_ping,
-                       GRPC_ERROR_CREATE("lame client channel"));
+    grpc_closure_sched(
+        exec_ctx, op->send_ping,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("lame client channel"));
   }
   GRPC_ERROR_UNREF(op->disconnect_with_error);
   if (op->on_consumed != NULL) {
diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.c
index 1186a4af63..a123c9ca43 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.c
@@ -288,10 +288,10 @@ static void send_shutdown(grpc_exec_ctx *exec_ctx, grpc_channel *channel,
   grpc_channel_element *elem;
 
   op->goaway_error =
-      send_goaway
-          ? grpc_error_set_int(GRPC_ERROR_CREATE("Server shutdown"),
-                               GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_OK)
-          : GRPC_ERROR_NONE;
+      send_goaway ? grpc_error_set_int(
+                        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server shutdown"),
+                        GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_OK)
+                  : GRPC_ERROR_NONE;
   op->set_accept_stream = true;
   sc->slice = grpc_slice_from_copied_string("Server shutdown");
   op->disconnect_with_error = send_disconnect;
@@ -712,8 +712,9 @@ static void maybe_finish_shutdown(grpc_exec_ctx *exec_ctx,
     return;
   }
 
-  kill_pending_work_locked(exec_ctx, server,
-                           GRPC_ERROR_CREATE("Server Shutdown"));
+  kill_pending_work_locked(
+      exec_ctx, server,
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server Shutdown"));
 
   if (server->root_channel_data.next != &server->root_channel_data ||
       server->listeners_destroyed < num_listeners(server)) {
@@ -771,8 +772,8 @@ static void server_on_recv_initial_metadata(grpc_exec_ctx *exec_ctx, void *ptr,
     /* do nothing */
   } else {
     grpc_error *src_error = error;
-    error =
-        GRPC_ERROR_CREATE_REFERENCING("Missing :authority or :path", &error, 1);
+    error = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+        "Missing :authority or :path", &error, 1);
     GRPC_ERROR_UNREF(src_error);
   }
 
@@ -1219,7 +1220,8 @@ void grpc_server_setup_transport(grpc_exec_ctx *exec_ctx, grpc_server *s,
   op->on_connectivity_state_change = &chand->channel_connectivity_changed;
   op->connectivity_state = &chand->connectivity_state;
   if (gpr_atm_acq_load(&s->shutdown_flag) != 0) {
-    op->disconnect_with_error = GRPC_ERROR_CREATE("Server shutdown");
+    op->disconnect_with_error =
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server shutdown");
   }
   grpc_transport_perform_op(exec_ctx, transport, op);
 }
@@ -1277,8 +1279,9 @@ void grpc_server_shutdown_and_notify(grpc_server *server,
 
   /* collect all unregistered then registered calls */
   gpr_mu_lock(&server->mu_call);
-  kill_pending_work_locked(&exec_ctx, server,
-                           GRPC_ERROR_CREATE("Server Shutdown"));
+  kill_pending_work_locked(
+      &exec_ctx, server,
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server Shutdown"));
   gpr_mu_unlock(&server->mu_call);
 
   maybe_finish_shutdown(&exec_ctx, server);
@@ -1308,8 +1311,9 @@ void grpc_server_cancel_all_calls(grpc_server *server) {
   channel_broadcaster_init(server, &broadcaster);
   gpr_mu_unlock(&server->mu_global);
 
-  channel_broadcaster_shutdown(&exec_ctx, &broadcaster, false /* send_goaway */,
-                               GRPC_ERROR_CREATE("Cancelling all calls"));
+  channel_broadcaster_shutdown(
+      &exec_ctx, &broadcaster, false /* send_goaway */,
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Cancelling all calls"));
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -1357,16 +1361,16 @@ static grpc_call_error queue_call_request(grpc_exec_ctx *exec_ctx,
   int request_id;
   if (gpr_atm_acq_load(&server->shutdown_flag)) {
     fail_call(exec_ctx, server, cq_idx, rc,
-              GRPC_ERROR_CREATE("Server Shutdown"));
+              GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server Shutdown"));
     return GRPC_CALL_OK;
   }
   request_id = gpr_stack_lockfree_pop(server->request_freelist_per_cq[cq_idx]);
   if (request_id == -1) {
     /* out of request ids: just fail this one */
     fail_call(exec_ctx, server, cq_idx, rc,
-              grpc_error_set_int(GRPC_ERROR_CREATE("Out of request ids"),
-                                 GRPC_ERROR_INT_LIMIT,
-                                 server->max_requested_calls_per_cq));
+              grpc_error_set_int(
+                  GRPC_ERROR_CREATE_FROM_STATIC_STRING("Out of request ids"),
+                  GRPC_ERROR_INT_LIMIT, server->max_requested_calls_per_cq));
     return GRPC_CALL_OK;
   }
   switch (rc->type) {
diff --git a/src/core/lib/surface/validate_metadata.c b/src/core/lib/surface/validate_metadata.c
index 7ec9137265..6e76c4efe7 100644
--- a/src/core/lib/surface/validate_metadata.c
+++ b/src/core/lib/surface/validate_metadata.c
@@ -39,6 +39,7 @@
 #include <grpc/support/port_platform.h>
 
 #include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 
 static grpc_error *conforms_to(grpc_slice slice, const uint8_t *legal_bits,
@@ -52,9 +53,10 @@ static grpc_error *conforms_to(grpc_slice slice, const uint8_t *legal_bits,
     if ((legal_bits[byte] & (1 << bit)) == 0) {
       char *dump = grpc_dump_slice(slice, GPR_DUMP_HEX | GPR_DUMP_ASCII);
       grpc_error *error = grpc_error_set_str(
-          grpc_error_set_int(GRPC_ERROR_CREATE(err_desc), GRPC_ERROR_INT_OFFSET,
+          grpc_error_set_int(GRPC_ERROR_CREATE_FROM_COPIED_STRING(err_desc),
+                             GRPC_ERROR_INT_OFFSET,
                              p - GRPC_SLICE_START_PTR(slice)),
-          GRPC_ERROR_STR_RAW_BYTES, dump);
+          GRPC_ERROR_STR_RAW_BYTES, grpc_slice_from_copied_string(dump));
       gpr_free(dump);
       return error;
     }
@@ -74,10 +76,12 @@ grpc_error *grpc_validate_header_key_is_legal(grpc_slice slice) {
       0x80, 0xfe, 0xff, 0xff, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
   if (GRPC_SLICE_LENGTH(slice) == 0) {
-    return GRPC_ERROR_CREATE("Metadata keys cannot be zero length");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Metadata keys cannot be zero length");
   }
   if (GRPC_SLICE_START_PTR(slice)[0] == ':') {
-    return GRPC_ERROR_CREATE("Metadata keys cannot start with :");
+    return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "Metadata keys cannot start with :");
   }
   return conforms_to(slice, legal_header_bits, "Illegal header key");
 }
diff --git a/src/core/lib/transport/connectivity_state.c b/src/core/lib/transport/connectivity_state.c
index afe1f6164d..3757b25267 100644
--- a/src/core/lib/transport/connectivity_state.c
+++ b/src/core/lib/transport/connectivity_state.c
@@ -79,7 +79,8 @@ void grpc_connectivity_state_destroy(grpc_exec_ctx *exec_ctx,
       *w->current = GRPC_CHANNEL_SHUTDOWN;
       error = GRPC_ERROR_NONE;
     } else {
-      error = GRPC_ERROR_CREATE("Shutdown connectivity owner");
+      error =
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Shutdown connectivity owner");
     }
     grpc_closure_sched(exec_ctx, w->notify, error);
     gpr_free(w);
diff --git a/src/core/lib/transport/error_utils.c b/src/core/lib/transport/error_utils.c
index ef55e561fb..4e70f8749d 100644
--- a/src/core/lib/transport/error_utils.c
+++ b/src/core/lib/transport/error_utils.c
@@ -55,7 +55,7 @@ static grpc_error *recursively_find_error_with_field(grpc_error *error,
 }
 
 void grpc_error_get_status(grpc_error *error, gpr_timespec deadline,
-                           grpc_status_code *code, const char **msg,
+                           grpc_status_code *code, grpc_slice *slice,
                            grpc_http2_error_code *http_error) {
   // Start with the parent error and recurse through the tree of children
   // until we find the first one that has a status code.
@@ -97,11 +97,11 @@ void grpc_error_get_status(grpc_error *error, gpr_timespec deadline,
 
   // If the error has a status message, use it.  Otherwise, fall back to
   // the error description.
-  if (msg != NULL) {
-    *msg = grpc_error_get_str(found_error, GRPC_ERROR_STR_GRPC_MESSAGE);
-    if (*msg == NULL && error != GRPC_ERROR_NONE) {
-      *msg = grpc_error_get_str(found_error, GRPC_ERROR_STR_DESCRIPTION);
-      if (*msg == NULL) *msg = "unknown error";  // Just in case.
+  if (slice != NULL) {
+    if (!grpc_error_get_str(found_error, GRPC_ERROR_STR_GRPC_MESSAGE, slice)) {
+      if (!grpc_error_get_str(found_error, GRPC_ERROR_STR_DESCRIPTION, slice)) {
+        *slice = grpc_slice_from_static_string("unknown error");
+      }
     }
   }
 
diff --git a/src/core/lib/transport/error_utils.h b/src/core/lib/transport/error_utils.h
index 105338880a..3b44466ab8 100644
--- a/src/core/lib/transport/error_utils.h
+++ b/src/core/lib/transport/error_utils.h
@@ -44,7 +44,7 @@
 /// attributes (code, msg, http_status) are unneeded, they can be passed as
 /// NULL.
 void grpc_error_get_status(grpc_error *error, gpr_timespec deadline,
-                           grpc_status_code *code, const char **msg,
+                           grpc_status_code *code, grpc_slice *slice,
                            grpc_http2_error_code *http_status);
 
 /// A utility function to check whether there is a clear status code that
diff --git a/src/core/lib/transport/metadata_batch.c b/src/core/lib/transport/metadata_batch.c
index fc2c52bd8a..fa73244aa4 100644
--- a/src/core/lib/transport/metadata_batch.c
+++ b/src/core/lib/transport/metadata_batch.c
@@ -101,12 +101,10 @@ void grpc_metadata_batch_destroy(grpc_exec_ctx *exec_ctx,
 }
 
 grpc_error *grpc_attach_md_to_error(grpc_error *src, grpc_mdelem md) {
-  char *k = grpc_slice_to_c_string(GRPC_MDKEY(md));
-  char *v = grpc_slice_to_c_string(GRPC_MDVALUE(md));
   grpc_error *out = grpc_error_set_str(
-      grpc_error_set_str(src, GRPC_ERROR_STR_KEY, k), GRPC_ERROR_STR_VALUE, v);
-  gpr_free(k);
-  gpr_free(v);
+      grpc_error_set_str(src, GRPC_ERROR_STR_KEY,
+                         grpc_slice_ref_internal(GRPC_MDKEY(md))),
+      GRPC_ERROR_STR_VALUE, grpc_slice_ref_internal(GRPC_MDVALUE(md)));
   return out;
 }
 
@@ -126,7 +124,8 @@ static grpc_error *maybe_link_callout(grpc_metadata_batch *batch,
     return GRPC_ERROR_NONE;
   }
   return grpc_attach_md_to_error(
-      GRPC_ERROR_CREATE("Unallowed duplicate metadata"), storage->md);
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Unallowed duplicate metadata"),
+      storage->md);
 }
 
 static void maybe_unlink_callout(grpc_metadata_batch *batch,
@@ -302,7 +301,7 @@ static void add_error(grpc_error **composite, grpc_error *error,
                       const char *composite_error_string) {
   if (error == GRPC_ERROR_NONE) return;
   if (*composite == GRPC_ERROR_NONE) {
-    *composite = GRPC_ERROR_CREATE(composite_error_string);
+    *composite = GRPC_ERROR_CREATE_FROM_COPIED_STRING(composite_error_string);
   }
   *composite = grpc_error_add_child(*composite, error);
 }
diff --git a/src/core/lib/transport/service_config.c b/src/core/lib/transport/service_config.c
index 12da2a88fe..1195f75044 100644
--- a/src/core/lib/transport/service_config.c
+++ b/src/core/lib/transport/service_config.c
@@ -93,6 +93,18 @@ void grpc_service_config_destroy(grpc_service_config* service_config) {
   gpr_free(service_config);
 }
 
+void grpc_service_config_parse_global_params(
+    const grpc_service_config* service_config,
+    void (*process_json)(const grpc_json* json, void* arg), void* arg) {
+  const grpc_json* json = service_config->json_tree;
+  if (json->type != GRPC_JSON_OBJECT || json->key != NULL) return;
+  for (grpc_json* field = json->child; field != NULL; field = field->next) {
+    if (field->key == NULL) return;
+    if (strcmp(field->key, "methodConfig") == 0) continue;
+    process_json(field, arg);
+  }
+}
+
 const char* grpc_service_config_get_lb_policy_name(
     const grpc_service_config* service_config) {
   const grpc_json* json = service_config->json_tree;
diff --git a/src/core/lib/transport/service_config.h b/src/core/lib/transport/service_config.h
index cd739a593c..ebfc59b534 100644
--- a/src/core/lib/transport/service_config.h
+++ b/src/core/lib/transport/service_config.h
@@ -42,6 +42,12 @@ typedef struct grpc_service_config grpc_service_config;
 grpc_service_config* grpc_service_config_create(const char* json_string);
 void grpc_service_config_destroy(grpc_service_config* service_config);
 
+/// Invokes \a process_json() for each global parameter in the service
+/// config.  \a arg is passed as the second argument to \a process_json().
+void grpc_service_config_parse_global_params(
+    const grpc_service_config* service_config,
+    void (*process_json)(const grpc_json* json, void* arg), void* arg);
+
 /// Gets the LB policy name from \a service_config.
 /// Returns NULL if no LB policy name was specified.
 /// Caller does NOT take ownership.