Merge remote-tracking branch 'upstream/master' into base64_decode

28 files changed, 786 insertions, 158 deletions

diff --git a/src/core/ext/lb_policy/round_robin/round_robin.c b/src/core/ext/lb_policy/round_robin/round_robin.c
index 8645333c8e..da2cdfe8e9 100644
--- a/src/core/ext/lb_policy/round_robin/round_robin.c
+++ b/src/core/ext/lb_policy/round_robin/round_robin.c
@@ -31,6 +31,34 @@
  *
  */
 
+/** Round Robin Policy.
+ *
+ * This policy keeps:
+ * - A circular list of ready (connected) subchannels, the *readylist*. An empty
+ *   readylist consists solely of its root (dummy) node.
+ * - A pointer to the last element picked from the readylist, the *lastpick*.
+ *   Initially set to point to the readylist's root.
+ *
+ * Behavior:
+ * - When a subchannel connects, it's *prepended* to the readylist's root node.
+ *   Ie, if readylist = A <-> B <-> ROOT <-> C
+ *                      ^                    ^
+ *                      |____________________|
+ *   and subchannel D becomes connected, the addition of D to the readylist
+ *   results in  readylist = A <-> B <-> D <-> ROOT <-> C
+ *                           ^                          ^
+ *                           |__________________________|
+ * - When a subchannel disconnects, it's removed from the readylist. If the
+ *   subchannel being removed was the most recently picked, the *lastpick*
+ *   pointer moves to the removed node's previous element. Note that if the
+ *   readylist only had one element, this is still legal, as the lastpick would
+ *   point to the dummy root node, for an empty readylist.
+ * - Upon picking, *lastpick* is updated to point to the returned (connected)
+ *   subchannel. Note that it's possible that the selected subchannel becomes
+ *   disconnected in the interim between the selection and the actual usage of
+ *   the subchannel by the caller.
+ */
+
 #include <string.h>
 
 #include <grpc/support/alloc.h>
@@ -173,9 +201,7 @@ static void remove_disconnected_sc_locked(round_robin_lb_policy *p,
     return;
   }
   if (node == p->ready_list_last_pick) {
-    /* If removing the lastly picked node, reset the last pick pointer to the
-     * dummy root of the list */
-    p->ready_list_last_pick = &p->ready_list;
+    p->ready_list_last_pick = p->ready_list_last_pick->prev;
   }
 
   /* removing last item */
@@ -345,8 +371,8 @@ static int rr_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     *target = grpc_subchannel_get_connected_subchannel(selected->subchannel);
     if (grpc_lb_round_robin_trace) {
       gpr_log(GPR_DEBUG,
-              "[RR PICK] TARGET <-- CONNECTED SUBCHANNEL %p (NODE %p)",
-              selected->subchannel, selected);
+              "[RR PICK] TARGET <-- CONNECTED SUBCHANNEL %p (NODE %p)", *target,
+              selected);
     }
     /* only advance the last picked pointer if the selection was used */
     advance_last_picked_locked(p);
@@ -526,7 +552,7 @@ static void round_robin_factory_ref(grpc_lb_policy_factory *factory) {}
 
 static void round_robin_factory_unref(grpc_lb_policy_factory *factory) {}
 
-static grpc_lb_policy *create_round_robin(grpc_exec_ctx *exec_ctx,
+static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
                                           grpc_lb_policy_factory *factory,
                                           grpc_lb_policy_args *args) {
   GPR_ASSERT(args->addresses != NULL);
@@ -582,7 +608,7 @@ static grpc_lb_policy *create_round_robin(grpc_exec_ctx *exec_ctx,
 }
 
 static const grpc_lb_policy_factory_vtable round_robin_factory_vtable = {
-    round_robin_factory_ref, round_robin_factory_unref, create_round_robin,
+    round_robin_factory_ref, round_robin_factory_unref, round_robin_create,
     "round_robin"};
 
 static grpc_lb_policy_factory round_robin_lb_policy_factory = {
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c b/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
new file mode 100644
index 0000000000..ca435c25ce
--- /dev/null
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
@@ -0,0 +1,95 @@
+/*
+ *
+ * Copyright 2016, 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/grpc.h>
+#include <grpc/grpc_posix.h>
+#include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_SUPPORT_CHANNELS_FROM_FD
+
+#include <fcntl.h>
+
+#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/iomgr/tcp_posix.h"
+#include "src/core/lib/surface/api_trace.h"
+#include "src/core/lib/surface/channel.h"
+#include "src/core/lib/transport/transport.h"
+
+grpc_channel *grpc_insecure_channel_create_from_fd(
+    const char *target, int fd, const grpc_channel_args *args) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  GRPC_API_TRACE("grpc_insecure_channel_create(target=%p, fd=%d, args=%p)", 3,
+                 (target, fd, args));
+
+  grpc_arg default_authority_arg;
+  default_authority_arg.type = GRPC_ARG_STRING;
+  default_authority_arg.key = GRPC_ARG_DEFAULT_AUTHORITY;
+  default_authority_arg.value.string = "test.authority";
+  grpc_channel_args *final_args =
+      grpc_channel_args_copy_and_add(args, &default_authority_arg, 1);
+
+  int flags = fcntl(fd, F_GETFL, 0);
+  GPR_ASSERT(fcntl(fd, F_SETFL, flags | O_NONBLOCK) == 0);
+
+  grpc_endpoint *client =
+      grpc_tcp_create(grpc_fd_create(fd, "client"),
+                      GRPC_TCP_DEFAULT_READ_SLICE_SIZE, "fd-client");
+
+  grpc_transport *transport =
+      grpc_create_chttp2_transport(&exec_ctx, final_args, client, 1);
+  GPR_ASSERT(transport);
+  grpc_channel *channel = grpc_channel_create(
+      &exec_ctx, target, final_args, GRPC_CLIENT_DIRECT_CHANNEL, transport);
+  grpc_channel_args_destroy(final_args);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL, 0);
+
+  grpc_exec_ctx_finish(&exec_ctx);
+
+  return channel != NULL ? channel : grpc_lame_client_channel_create(
+                                         target, GRPC_STATUS_INTERNAL,
+                                         "Failed to create client channel");
+}
+
+#else  // !GPR_SUPPORT_CHANNELS_FROM_FD
+
+grpc_channel *grpc_insecure_channel_create_from_fd(
+    const char *target, int fd, const grpc_channel_args *args) {
+  GPR_ASSERT(0);
+  return NULL;
+}
+
+#endif  // GPR_SUPPORT_CHANNELS_FROM_FD
diff --git a/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c b/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
new file mode 100644
index 0000000000..96bf4d6f30
--- /dev/null
+++ b/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
@@ -0,0 +1,82 @@
+/*
+ *
+ * Copyright 2016, 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/grpc.h>
+#include <grpc/grpc_posix.h>
+#include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_SUPPORT_CHANNELS_FROM_FD
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/iomgr/tcp_posix.h"
+#include "src/core/lib/surface/completion_queue.h"
+#include "src/core/lib/surface/server.h"
+
+void grpc_server_add_insecure_channel_from_fd(grpc_server *server,
+                                              grpc_completion_queue *cq,
+                                              int fd) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+
+  char *name;
+  gpr_asprintf(&name, "fd:%d", fd);
+
+  grpc_endpoint *server_endpoint = grpc_tcp_create(
+      grpc_fd_create(fd, name), GRPC_TCP_DEFAULT_READ_SLICE_SIZE, name);
+
+  gpr_free(name);
+
+  const grpc_channel_args *server_args = grpc_server_get_channel_args(server);
+  grpc_transport *transport = grpc_create_chttp2_transport(
+      &exec_ctx, server_args, server_endpoint, 0 /* is_client */);
+  grpc_endpoint_add_to_pollset(&exec_ctx, server_endpoint, grpc_cq_pollset(cq));
+  grpc_server_setup_transport(&exec_ctx, server, transport, NULL, server_args);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL, 0);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
+#else  // !GPR_SUPPORT_CHANNELS_FROM_FD
+
+void grpc_server_add_insecure_channel_from_fd(grpc_server *server,
+                                              grpc_completion_queue *cq,
+                                              int fd) {
+  GPR_ASSERT(0);
+}
+
+#endif  // GPR_SUPPORT_CHANNELS_FROM_FD
diff --git a/src/core/lib/channel/channel_args.c b/src/core/lib/channel/channel_args.c
index 569be4dc28..d53ce904a9 100644
--- a/src/core/lib/channel/channel_args.c
+++ b/src/core/lib/channel/channel_args.c
@@ -35,6 +35,7 @@
 #include <grpc/grpc.h>
 #include "src/core/lib/support/string.h"
 
+#include <grpc/compression.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
@@ -181,6 +182,7 @@ grpc_compression_algorithm grpc_channel_args_get_compression_algorithm(
 
 grpc_channel_args *grpc_channel_args_set_compression_algorithm(
     grpc_channel_args *a, grpc_compression_algorithm algorithm) {
+  GPR_ASSERT(algorithm < GRPC_COMPRESS_ALGORITHMS_COUNT);
   grpc_arg tmp;
   tmp.type = GRPC_ARG_INTEGER;
   tmp.key = GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM;
@@ -200,7 +202,8 @@ static int find_compression_algorithm_states_bitset(const grpc_channel_args *a,
           !strcmp(GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET,
                   a->args[i].key)) {
         *states_arg = &a->args[i].value.integer;
-        return 1; /* GPR_TRUE */
+        **states_arg |= 0x1; /* forcefully enable support for no compression */
+        return 1;
       }
     }
   }
@@ -214,10 +217,18 @@ grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
   const int states_arg_found =
       find_compression_algorithm_states_bitset(*a, &states_arg);
 
-  if (states_arg_found) {
+  if (grpc_channel_args_get_compression_algorithm(*a) == algorithm &&
+      state == 0) {
+    char *algo_name = NULL;
+    GPR_ASSERT(grpc_compression_algorithm_name(algorithm, &algo_name) != 0);
+    gpr_log(GPR_ERROR,
+            "Tried to disable default compression algorithm '%s'. The "
+            "operation has been ignored.",
+            algo_name);
+  } else if (states_arg_found) {
     if (state != 0) {
       GPR_BITSET((unsigned *)states_arg, algorithm);
-    } else {
+    } else if (algorithm != GRPC_COMPRESS_NONE) {
       GPR_BITCLEAR((unsigned *)states_arg, algorithm);
     }
   } else {
@@ -229,7 +240,7 @@ grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
     tmp.value.integer = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
     if (state != 0) {
       GPR_BITSET((unsigned *)&tmp.value.integer, algorithm);
-    } else {
+    } else if (algorithm != GRPC_COMPRESS_NONE) {
       GPR_BITCLEAR((unsigned *)&tmp.value.integer, algorithm);
     }
     result = grpc_channel_args_copy_and_add(*a, &tmp, 1);
@@ -239,11 +250,11 @@ grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
   return result;
 }
 
-int grpc_channel_args_compression_algorithm_get_states(
+uint32_t grpc_channel_args_compression_algorithm_get_states(
     const grpc_channel_args *a) {
   int *states_arg;
   if (find_compression_algorithm_states_bitset(a, &states_arg)) {
-    return *states_arg;
+    return (uint32_t)*states_arg;
   } else {
     return (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1; /* All algs. enabled */
   }
diff --git a/src/core/lib/channel/channel_args.h b/src/core/lib/channel/channel_args.h
index 23c7b7b897..653d04f427 100644
--- a/src/core/lib/channel/channel_args.h
+++ b/src/core/lib/channel/channel_args.h
@@ -81,7 +81,7 @@ grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
  *
  * The i-th bit of the returned bitset corresponds to the i-th entry in the
  * grpc_compression_algorithm enum. */
-int grpc_channel_args_compression_algorithm_get_states(
+uint32_t grpc_channel_args_compression_algorithm_get_states(
     const grpc_channel_args *a);
 
 int grpc_channel_args_compare(const grpc_channel_args *a,
diff --git a/src/core/lib/channel/compress_filter.c b/src/core/lib/channel/compress_filter.c
index 7c8c1d6f31..4fe9a7f045 100644
--- a/src/core/lib/channel/compress_filter.c
+++ b/src/core/lib/channel/compress_filter.c
@@ -73,8 +73,8 @@ typedef struct call_data {
 typedef struct channel_data {
   /** The default, channel-level, compression algorithm */
   grpc_compression_algorithm default_compression_algorithm;
-  /** Compression options for the channel */
-  grpc_compression_options compression_options;
+  /** Bitset of enabled algorithms */
+  uint32_t enabled_algorithms_bitset;
   /** Supported compression algorithms */
   uint32_t supported_compression_algorithms;
 } channel_data;
@@ -96,9 +96,8 @@ static grpc_mdelem *compression_md_filter(void *user_data, grpc_mdelem *md) {
               md_c_str);
       calld->compression_algorithm = GRPC_COMPRESS_NONE;
     }
-    if (grpc_compression_options_is_algorithm_enabled(
-            &channeld->compression_options, calld->compression_algorithm) ==
-        0) {
+    if (!GPR_BITGET(channeld->enabled_algorithms_bitset,
+                    calld->compression_algorithm)) {
       gpr_log(GPR_ERROR,
               "Invalid compression algorithm: '%s' (previously disabled). "
               "Ignoring.",
@@ -282,32 +281,26 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
                               grpc_channel_element *elem,
                               grpc_channel_element_args *args) {
   channel_data *channeld = elem->channel_data;
-  grpc_compression_algorithm algo_idx;
 
-  grpc_compression_options_init(&channeld->compression_options);
-  channeld->compression_options.enabled_algorithms_bitset =
-      (uint32_t)grpc_channel_args_compression_algorithm_get_states(
-          args->channel_args);
+  channeld->enabled_algorithms_bitset =
+      grpc_channel_args_compression_algorithm_get_states(args->channel_args);
 
   channeld->default_compression_algorithm =
       grpc_channel_args_get_compression_algorithm(args->channel_args);
   /* Make sure the default isn't disabled. */
-  if (!grpc_compression_options_is_algorithm_enabled(
-          &channeld->compression_options,
-          channeld->default_compression_algorithm)) {
+  if (!GPR_BITGET(channeld->enabled_algorithms_bitset,
+                  channeld->default_compression_algorithm)) {
     gpr_log(GPR_DEBUG,
             "compression algorithm %d not enabled: switching to none",
             channeld->default_compression_algorithm);
     channeld->default_compression_algorithm = GRPC_COMPRESS_NONE;
   }
-  channeld->compression_options.default_compression_algorithm =
-      channeld->default_compression_algorithm;
 
-  channeld->supported_compression_algorithms = 0;
-  for (algo_idx = 0; algo_idx < GRPC_COMPRESS_ALGORITHMS_COUNT; ++algo_idx) {
+  channeld->supported_compression_algorithms = 1; /* always support identity */
+  for (grpc_compression_algorithm algo_idx = 1;
+       algo_idx < GRPC_COMPRESS_ALGORITHMS_COUNT; ++algo_idx) {
     /* skip disabled algorithms */
-    if (grpc_compression_options_is_algorithm_enabled(
-            &channeld->compression_options, algo_idx) == 0) {
+    if (!GPR_BITGET(channeld->enabled_algorithms_bitset, algo_idx)) {
       continue;
     }
     channeld->supported_compression_algorithms |= 1u << algo_idx;
diff --git a/src/core/lib/channel/compress_filter.h b/src/core/lib/channel/compress_filter.h
index 0ce5d08837..e4a2a829d5 100644
--- a/src/core/lib/channel/compress_filter.h
+++ b/src/core/lib/channel/compress_filter.h
@@ -34,9 +34,9 @@
 #ifndef GRPC_CORE_LIB_CHANNEL_COMPRESS_FILTER_H
 #define GRPC_CORE_LIB_CHANNEL_COMPRESS_FILTER_H
 
-#include "src/core/lib/channel/channel_stack.h"
+#include <grpc/impl/codegen/compression_types.h>
 
-#define GRPC_COMPRESS_REQUEST_ALGORITHM_KEY "grpc-internal-encoding-request"
+#include "src/core/lib/channel/channel_stack.h"
 
 extern int grpc_compression_trace;
 
@@ -48,7 +48,7 @@ extern int grpc_compression_trace;
  *  - Channel configuration, as established at channel creation time.
  *  - The metadata accompanying the outgoing data to be compressed. This is
  *    taken as a request only. We may choose not to honor it. The metadata key
- *    is given by \a GRPC_COMPRESS_REQUEST_ALGORITHM_KEY.
+ *    is given by \a GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY.
  *
  * Compression can be disabled for concrete messages (for instance in order to
  * prevent CRIME/BEAST type attacks) by having the GRPC_WRITE_NO_COMPRESS set in
diff --git a/src/core/lib/compression/compression_algorithm.c b/src/core/lib/compression/compression.c
index 820871d579..54efb5e855 100644
--- a/src/core/lib/compression/compression_algorithm.c
+++ b/src/core/lib/compression/compression.c
@@ -125,6 +125,28 @@ grpc_mdelem *grpc_compression_encoding_mdelem(
   return NULL;
 }
 
+void grpc_compression_options_init(grpc_compression_options *opts) {
+  memset(opts, 0, sizeof(*opts));
+  /* all enabled by default */
+  opts->enabled_algorithms_bitset = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
+}
+
+void grpc_compression_options_enable_algorithm(
+    grpc_compression_options *opts, grpc_compression_algorithm algorithm) {
+  GPR_BITSET(&opts->enabled_algorithms_bitset, algorithm);
+}
+
+void grpc_compression_options_disable_algorithm(
+    grpc_compression_options *opts, grpc_compression_algorithm algorithm) {
+  GPR_BITCLEAR(&opts->enabled_algorithms_bitset, algorithm);
+}
+
+int grpc_compression_options_is_algorithm_enabled(
+    const grpc_compression_options *opts,
+    grpc_compression_algorithm algorithm) {
+  return GPR_BITGET(opts->enabled_algorithms_bitset, algorithm);
+}
+
 /* TODO(dgq): Add the ability to specify parameters to the individual
  * compression algorithms */
 grpc_compression_algorithm grpc_compression_algorithm_for_level(
@@ -180,25 +202,3 @@ grpc_compression_algorithm grpc_compression_algorithm_for_level(
       abort();
   };
 }
-
-void grpc_compression_options_init(grpc_compression_options *opts) {
-  opts->enabled_algorithms_bitset = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
-  opts->default_compression_algorithm = GRPC_COMPRESS_NONE;
-}
-
-void grpc_compression_options_enable_algorithm(
-    grpc_compression_options *opts, grpc_compression_algorithm algorithm) {
-  GPR_BITSET(&opts->enabled_algorithms_bitset, algorithm);
-}
-
-void grpc_compression_options_disable_algorithm(
-    grpc_compression_options *opts, grpc_compression_algorithm algorithm) {
-  GPR_BITCLEAR(&opts->enabled_algorithms_bitset, algorithm);
-}
-
-int grpc_compression_options_is_algorithm_enabled(
-    const grpc_compression_options *opts,
-    grpc_compression_algorithm algorithm) {
-  if (algorithm >= GRPC_COMPRESS_ALGORITHMS_COUNT) return 0;
-  return GPR_BITGET(opts->enabled_algorithms_bitset, algorithm);
-}
diff --git a/src/core/lib/iomgr/socket_utils_common_posix.c b/src/core/lib/iomgr/socket_utils_common_posix.c
index fa83ceef30..2147c86d4d 100644
--- a/src/core/lib/iomgr/socket_utils_common_posix.c
+++ b/src/core/lib/iomgr/socket_utils_common_posix.c
@@ -111,6 +111,16 @@ int grpc_set_socket_ipv6_recvpktinfo_if_possible(int fd) {
 #endif
 }
 
+int grpc_set_socket_sndbuf(int fd, int buffer_size_bytes) {
+  return 0 == setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &buffer_size_bytes,
+                         sizeof(buffer_size_bytes));
+}
+
+int grpc_set_socket_rcvbuf(int fd, int buffer_size_bytes) {
+  return 0 == setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &buffer_size_bytes,
+                         sizeof(buffer_size_bytes));
+}
+
 /* set a socket to close on exec */
 int grpc_set_socket_cloexec(int fd, int close_on_exec) {
   int oldflags = fcntl(fd, F_GETFD, 0);
diff --git a/src/core/lib/iomgr/socket_utils_posix.h b/src/core/lib/iomgr/socket_utils_posix.h
index a8f6e5e658..7e41d1c870 100644
--- a/src/core/lib/iomgr/socket_utils_posix.h
+++ b/src/core/lib/iomgr/socket_utils_posix.h
@@ -78,6 +78,14 @@ int grpc_set_socket_ip_pktinfo_if_possible(int fd);
    If IPV6_RECVPKTINFO is not available, returns 1. */
 int grpc_set_socket_ipv6_recvpktinfo_if_possible(int fd);
 
+/* Tries to set the socket's send buffer to given size.
+   Returns 1 on success, 0 on failure. */
+int grpc_set_socket_sndbuf(int fd, int buffer_size_bytes);
+
+/* Tries to set the socket's receive buffer to given size.
+   Returns 1 on success, 0 on failure. */
+int grpc_set_socket_rcvbuf(int fd, int buffer_size_bytes);
+
 /* An enum to keep track of IPv4/IPv6 socket modes.
 
    Currently, this information is only used when a socket is first created, but
diff --git a/src/core/lib/iomgr/udp_server.c b/src/core/lib/iomgr/udp_server.c
index 98ffccd59b..16150687d3 100644
--- a/src/core/lib/iomgr/udp_server.c
+++ b/src/core/lib/iomgr/udp_server.c
@@ -210,6 +210,8 @@ static int prepare_socket(int fd, const struct sockaddr *addr,
                           size_t addr_len) {
   struct sockaddr_storage sockname_temp;
   socklen_t sockname_len;
+  /* Set send/receive socket buffers to 1 MB */
+  int buffer_size_bytes = 1024 * 1024;
 
   if (fd < 0) {
     goto error;
@@ -239,6 +241,18 @@ static int prepare_socket(int fd, const struct sockaddr *addr,
     goto error;
   }
 
+  if (!grpc_set_socket_sndbuf(fd, buffer_size_bytes)) {
+    gpr_log(GPR_ERROR, "Failed to set send buffer size to %d bytes",
+            buf_size_bytes);
+    goto error;
+  }
+
+  if (!grpc_set_socket_rcvbuf(fd, buffer_size_bytes)) {
+    gpr_log(GPR_ERROR, "Failed to set receive buffer size to %d bytes",
+            buf_size_bytes);
+    goto error;
+  }
+
   return grpc_sockaddr_get_port((struct sockaddr *)&sockname_temp);
 
 error:
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index e899bc8098..a9b1e25a77 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -40,6 +40,7 @@
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/slice.h>
 #include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
 
@@ -52,7 +53,9 @@
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/surface/completion_queue.h"
+#include "src/core/lib/transport/metadata.h"
 #include "src/core/lib/transport/static_metadata.h"
+#include "src/core/lib/transport/transport.h"
 
 /** The maximum number of concurrent batches possible.
     Based upon the maximum number of individually queueable ops in the batch
@@ -154,8 +157,8 @@ struct grpc_call {
   /* Call stats: only valid after trailing metadata received */
   grpc_call_stats stats;
 
-  /* Compression algorithm for the call */
-  grpc_compression_algorithm compression_algorithm;
+  /* Compression algorithm for *incoming* data */
+  grpc_compression_algorithm incoming_compression_algorithm;
   /* Supported encodings (compression algorithms), a bitset */
   uint32_t encodings_accepted_by_peer;
 
@@ -214,6 +217,9 @@ static void execute_op(grpc_exec_ctx *exec_ctx, grpc_call *call,
 static grpc_call_error cancel_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
                                           grpc_status_code status,
                                           const char *description);
+static grpc_call_error close_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
+                                         grpc_status_code status,
+                                         const char *description);
 static void destroy_call(grpc_exec_ctx *exec_ctx, void *call_stack,
                          bool success);
 static void receiving_slice_ready(grpc_exec_ctx *exec_ctx, void *bctlp,
@@ -399,21 +405,27 @@ static void set_status_code(grpc_call *call, status_source source,
   /* TODO(ctiller): what to do about the flush that was previously here */
 }
 
-static void set_compression_algorithm(grpc_call *call,
-                                      grpc_compression_algorithm algo) {
+static void set_incoming_compression_algorithm(
+    grpc_call *call, grpc_compression_algorithm algo) {
   GPR_ASSERT(algo < GRPC_COMPRESS_ALGORITHMS_COUNT);
-  call->compression_algorithm = algo;
+  call->incoming_compression_algorithm = algo;
 }
 
 grpc_compression_algorithm grpc_call_test_only_get_compression_algorithm(
     grpc_call *call) {
   grpc_compression_algorithm algorithm;
   gpr_mu_lock(&call->mu);
-  algorithm = call->compression_algorithm;
+  algorithm = call->incoming_compression_algorithm;
   gpr_mu_unlock(&call->mu);
   return algorithm;
 }
 
+static grpc_compression_algorithm compression_algorithm_for_level_locked(
+    grpc_call *call, grpc_compression_level level) {
+  return grpc_compression_algorithm_for_level(level,
+                                              call->encodings_accepted_by_peer);
+}
+
 uint32_t grpc_call_test_only_get_message_flags(grpc_call *call) {
   uint32_t flags;
   gpr_mu_lock(&call->mu);
@@ -539,15 +551,28 @@ static grpc_linked_mdelem *linked_from_md(grpc_metadata *md) {
   return (grpc_linked_mdelem *)&md->internal_data;
 }
 
+static grpc_metadata *get_md_elem(grpc_metadata *metadata,
+                                  grpc_metadata *additional_metadata, int i,
+                                  int count) {
+  grpc_metadata *res =
+      i < count ? &metadata[i] : &additional_metadata[i - count];
+  GPR_ASSERT(res);
+  return res;
+}
+
 static int prepare_application_metadata(grpc_call *call, int count,
                                         grpc_metadata *metadata,
                                         int is_trailing,
-                                        int prepend_extra_metadata) {
+                                        int prepend_extra_metadata,
+                                        grpc_metadata *additional_metadata,
+                                        int additional_metadata_count) {
+  int total_count = count + additional_metadata_count;
   int i;
   grpc_metadata_batch *batch =
       &call->metadata_batch[0 /* is_receiving */][is_trailing];
-  for (i = 0; i < count; i++) {
-    grpc_metadata *md = &metadata[i];
+  for (i = 0; i < total_count; i++) {
+    const grpc_metadata *md =
+        get_md_elem(metadata, additional_metadata, i, count);
     grpc_linked_mdelem *l = (grpc_linked_mdelem *)&md->internal_data;
     GPR_ASSERT(sizeof(grpc_linked_mdelem) == sizeof(md->internal_data));
     l->md = grpc_mdelem_from_string_and_buffer(
@@ -566,9 +591,10 @@ static int prepare_application_metadata(grpc_call *call, int count,
       break;
     }
   }
-  if (i != count) {
+  if (i != total_count) {
     for (int j = 0; j <= i; j++) {
-      grpc_metadata *md = &metadata[j];
+      const grpc_metadata *md =
+          get_md_elem(metadata, additional_metadata, j, count);
       grpc_linked_mdelem *l = (grpc_linked_mdelem *)&md->internal_data;
       GRPC_MDELEM_UNREF(l->md);
     }
@@ -589,24 +615,36 @@ static int prepare_application_metadata(grpc_call *call, int count,
       }
     }
   }
-  for (i = 1; i < count; i++) {
-    linked_from_md(&metadata[i])->prev = linked_from_md(&metadata[i - 1]);
+  for (i = 1; i < total_count; i++) {
+    grpc_metadata *md = get_md_elem(metadata, additional_metadata, i, count);
+    grpc_metadata *prev_md =
+        get_md_elem(metadata, additional_metadata, i - 1, count);
+    linked_from_md(md)->prev = linked_from_md(prev_md);
   }
-  for (i = 0; i < count - 1; i++) {
-    linked_from_md(&metadata[i])->next = linked_from_md(&metadata[i + 1]);
+  for (i = 0; i < total_count - 1; i++) {
+    grpc_metadata *md = get_md_elem(metadata, additional_metadata, i, count);
+    grpc_metadata *next_md =
+        get_md_elem(metadata, additional_metadata, i + 1, count);
+    linked_from_md(md)->next = linked_from_md(next_md);
   }
-  switch (prepend_extra_metadata * 2 + (count != 0)) {
+
+  switch (prepend_extra_metadata * 2 + (total_count != 0)) {
     case 0:
       /* no prepend, no metadata => nothing to do */
       batch->list.head = batch->list.tail = NULL;
       break;
-    case 1:
+    case 1: {
       /* metadata, but no prepend */
-      batch->list.head = linked_from_md(&metadata[0]);
-      batch->list.tail = linked_from_md(&metadata[count - 1]);
+      grpc_metadata *first_md =
+          get_md_elem(metadata, additional_metadata, 0, count);
+      grpc_metadata *last_md =
+          get_md_elem(metadata, additional_metadata, total_count - 1, count);
+      batch->list.head = linked_from_md(first_md);
+      batch->list.tail = linked_from_md(last_md);
       batch->list.head->prev = NULL;
       batch->list.tail->next = NULL;
       break;
+    }
     case 2:
       /* prepend, but no md */
       batch->list.head = &call->send_extra_metadata[0];
@@ -615,17 +653,22 @@ static int prepare_application_metadata(grpc_call *call, int count,
       batch->list.head->prev = NULL;
       batch->list.tail->next = NULL;
       break;
-    case 3:
+    case 3: {
       /* prepend AND md */
+      grpc_metadata *first_md =
+          get_md_elem(metadata, additional_metadata, 0, count);
+      grpc_metadata *last_md =
+          get_md_elem(metadata, additional_metadata, total_count - 1, count);
       batch->list.head = &call->send_extra_metadata[0];
       call->send_extra_metadata[call->send_extra_metadata_count - 1].next =
-          linked_from_md(&metadata[0]);
-      linked_from_md(&metadata[0])->prev =
+          linked_from_md(first_md);
+      linked_from_md(first_md)->prev =
           &call->send_extra_metadata[call->send_extra_metadata_count - 1];
-      batch->list.tail = linked_from_md(&metadata[count - 1]);
+      batch->list.tail = linked_from_md(last_md);
       batch->list.head->prev = NULL;
       batch->list.tail->next = NULL;
       break;
+    }
     default:
       GPR_UNREACHABLE_CODE(return 0);
   }
@@ -694,48 +737,102 @@ grpc_call_error grpc_call_cancel_with_status(grpc_call *c,
   return r;
 }
 
-typedef struct cancel_closure {
+typedef struct termination_closure {
   grpc_closure closure;
   grpc_call *call;
   grpc_status_code status;
-} cancel_closure;
+  gpr_slice optional_message;
+  grpc_closure *op_closure;
+  enum { TC_CANCEL, TC_CLOSE } type;
+} termination_closure;
 
-static void done_cancel(grpc_exec_ctx *exec_ctx, void *ccp, bool success) {
-  cancel_closure *cc = ccp;
-  GRPC_CALL_INTERNAL_UNREF(exec_ctx, cc->call, "cancel");
-  gpr_free(cc);
+static void done_termination(grpc_exec_ctx *exec_ctx, void *tcp, bool success) {
+  termination_closure *tc = tcp;
+  if (tc->type == TC_CANCEL) {
+    GRPC_CALL_INTERNAL_UNREF(exec_ctx, tc->call, "cancel");
+  }
+  if (tc->type == TC_CLOSE) {
+    GRPC_CALL_INTERNAL_UNREF(exec_ctx, tc->call, "close");
+  }
+  gpr_slice_unref(tc->optional_message);
+  if (tc->op_closure != NULL) {
+    grpc_exec_ctx_enqueue(exec_ctx, tc->op_closure, true, NULL);
+  }
+  gpr_free(tc);
 }
 
-static void send_cancel(grpc_exec_ctx *exec_ctx, void *ccp, bool success) {
+static void send_cancel(grpc_exec_ctx *exec_ctx, void *tcp, bool success) {
   grpc_transport_stream_op op;
-  cancel_closure *cc = ccp;
+  termination_closure *tc = tcp;
   memset(&op, 0, sizeof(op));
-  op.cancel_with_status = cc->status;
+  op.cancel_with_status = tc->status;
   /* reuse closure to catch completion */
-  grpc_closure_init(&cc->closure, done_cancel, cc);
-  op.on_complete = &cc->closure;
-  execute_op(exec_ctx, cc->call, &op);
+  grpc_closure_init(&tc->closure, done_termination, tc);
+  op.on_complete = &tc->closure;
+  execute_op(exec_ctx, tc->call, &op);
+}
+
+static void send_close(grpc_exec_ctx *exec_ctx, void *tcp, bool success) {
+  grpc_transport_stream_op op;
+  termination_closure *tc = tcp;
+  memset(&op, 0, sizeof(op));
+  tc->optional_message = gpr_slice_ref(tc->optional_message);
+  grpc_transport_stream_op_add_close(&op, tc->status, &tc->optional_message);
+  /* reuse closure to catch completion */
+  grpc_closure_init(&tc->closure, done_termination, tc);
+  tc->op_closure = op.on_complete;
+  op.on_complete = &tc->closure;
+  execute_op(exec_ctx, tc->call, &op);
+}
+
+static grpc_call_error terminate_with_status(grpc_exec_ctx *exec_ctx,
+                                             termination_closure *tc) {
+  grpc_mdstr *details = NULL;
+  if (GPR_SLICE_LENGTH(tc->optional_message) > 0) {
+    tc->optional_message = gpr_slice_ref(tc->optional_message);
+    details = grpc_mdstr_from_slice(tc->optional_message);
+  }
+
+  set_status_code(tc->call, STATUS_FROM_API_OVERRIDE, (uint32_t)tc->status);
+  set_status_details(tc->call, STATUS_FROM_API_OVERRIDE, details);
+
+  if (tc->type == TC_CANCEL) {
+    grpc_closure_init(&tc->closure, send_cancel, tc);
+    GRPC_CALL_INTERNAL_REF(tc->call, "cancel");
+  } else if (tc->type == TC_CLOSE) {
+    grpc_closure_init(&tc->closure, send_close, tc);
+    GRPC_CALL_INTERNAL_REF(tc->call, "close");
+  }
+  grpc_exec_ctx_enqueue(exec_ctx, &tc->closure, true, NULL);
+  return GRPC_CALL_OK;
 }
 
 static grpc_call_error cancel_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
                                           grpc_status_code status,
                                           const char *description) {
-  grpc_mdstr *details =
-      description ? grpc_mdstr_from_string(description) : NULL;
-  cancel_closure *cc = gpr_malloc(sizeof(*cc));
-
+  termination_closure *tc = gpr_malloc(sizeof(*tc));
+  memset(tc, 0, sizeof(termination_closure));
+  tc->type = TC_CANCEL;
+  tc->call = c;
+  tc->optional_message = gpr_slice_from_copied_string(description);
   GPR_ASSERT(status != GRPC_STATUS_OK);
+  tc->status = status;
 
-  set_status_code(c, STATUS_FROM_API_OVERRIDE, (uint32_t)status);
-  set_status_details(c, STATUS_FROM_API_OVERRIDE, details);
+  return terminate_with_status(exec_ctx, tc);
+}
 
-  grpc_closure_init(&cc->closure, send_cancel, cc);
-  cc->call = c;
-  cc->status = status;
-  GRPC_CALL_INTERNAL_REF(c, "cancel");
-  grpc_exec_ctx_enqueue(exec_ctx, &cc->closure, true, NULL);
+static grpc_call_error close_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
+                                         grpc_status_code status,
+                                         const char *description) {
+  termination_closure *tc = gpr_malloc(sizeof(*tc));
+  memset(tc, 0, sizeof(termination_closure));
+  tc->type = TC_CLOSE;
+  tc->call = c;
+  tc->optional_message = gpr_slice_from_copied_string(description);
+  GPR_ASSERT(status != GRPC_STATUS_OK);
+  tc->status = status;
 
-  return GRPC_CALL_OK;
+  return terminate_with_status(exec_ctx, tc);
 }
 
 static void execute_op(grpc_exec_ctx *exec_ctx, grpc_call *call,
@@ -876,9 +973,9 @@ static grpc_mdelem *recv_initial_filter(void *callp, grpc_mdelem *elem) {
   if (elem == NULL) {
     return NULL;
   } else if (elem->key == GRPC_MDSTR_GRPC_ENCODING) {
-    GPR_TIMER_BEGIN("compression_algorithm", 0);
-    set_compression_algorithm(call, decode_compression(elem));
-    GPR_TIMER_END("compression_algorithm", 0);
+    GPR_TIMER_BEGIN("incoming_compression_algorithm", 0);
+    set_incoming_compression_algorithm(call, decode_compression(elem));
+    GPR_TIMER_END("incoming_compression_algorithm", 0);
     return NULL;
   } else if (elem->key == GRPC_MDSTR_GRPC_ACCEPT_ENCODING) {
     GPR_TIMER_BEGIN("encodings_accepted_by_peer", 0);
@@ -1041,9 +1138,9 @@ static void process_data_after_md(grpc_exec_ctx *exec_ctx, batch_control *bctl,
   } else {
     call->test_only_last_message_flags = call->receiving_stream->flags;
     if ((call->receiving_stream->flags & GRPC_WRITE_INTERNAL_COMPRESS) &&
-        (call->compression_algorithm > GRPC_COMPRESS_NONE)) {
+        (call->incoming_compression_algorithm > GRPC_COMPRESS_NONE)) {
       *call->receiving_buffer = grpc_raw_compressed_byte_buffer_create(
-          NULL, 0, call->compression_algorithm);
+          NULL, 0, call->incoming_compression_algorithm);
     } else {
       *call->receiving_buffer = grpc_raw_byte_buffer_create(NULL, 0);
     }
@@ -1071,6 +1168,56 @@ static void receiving_stream_ready(grpc_exec_ctx *exec_ctx, void *bctlp,
   }
 }
 
+static void validate_filtered_metadata(grpc_exec_ctx *exec_ctx,
+                                       batch_control *bctl) {
+  grpc_call *call = bctl->call;
+  /* validate call->incoming_compression_algorithm */
+  if (call->incoming_compression_algorithm != GRPC_COMPRESS_NONE) {
+    const grpc_compression_algorithm algo =
+        call->incoming_compression_algorithm;
+    char *error_msg = NULL;
+    const grpc_compression_options compression_options =
+        grpc_channel_compression_options(call->channel);
+    /* check if algorithm is known */
+    if (algo >= GRPC_COMPRESS_ALGORITHMS_COUNT) {
+      gpr_asprintf(&error_msg, "Invalid compression algorithm value '%d'.",
+                   algo);
+      gpr_log(GPR_ERROR, error_msg);
+      close_with_status(exec_ctx, call, GRPC_STATUS_UNIMPLEMENTED, error_msg);
+    } else if (grpc_compression_options_is_algorithm_enabled(
+                   &compression_options, algo) == 0) {
+      /* check if algorithm is supported by current channel config */
+      char *algo_name;
+      grpc_compression_algorithm_name(algo, &algo_name);
+      gpr_asprintf(&error_msg, "Compression algorithm '%s' is disabled.",
+                   algo_name);
+      gpr_log(GPR_ERROR, error_msg);
+      close_with_status(exec_ctx, call, GRPC_STATUS_UNIMPLEMENTED, error_msg);
+    } else {
+      call->incoming_compression_algorithm = algo;
+    }
+    gpr_free(error_msg);
+  }
+
+  /* make sure the received grpc-encoding is amongst the ones listed in
+   * grpc-accept-encoding */
+  GPR_ASSERT(call->encodings_accepted_by_peer != 0);
+  if (!GPR_BITGET(call->encodings_accepted_by_peer,
+                  call->incoming_compression_algorithm)) {
+    extern int grpc_compression_trace;
+    if (grpc_compression_trace) {
+      char *algo_name;
+      grpc_compression_algorithm_name(call->incoming_compression_algorithm,
+                                      &algo_name);
+      gpr_log(GPR_ERROR,
+              "Compression algorithm (grpc-encoding = '%s') not present in "
+              "the bitset of accepted encodings (grpc-accept-encodings: "
+              "'0x%x')",
+              algo_name, call->encodings_accepted_by_peer);
+    }
+  }
+}
+
 static void receiving_initial_metadata_ready(grpc_exec_ctx *exec_ctx,
                                              void *bctlp, bool success) {
   batch_control *bctl = bctlp;
@@ -1085,24 +1232,10 @@ static void receiving_initial_metadata_ready(grpc_exec_ctx *exec_ctx,
         &call->metadata_batch[1 /* is_receiving */][0 /* is_trailing */];
     grpc_metadata_batch_filter(md, recv_initial_filter, call);
 
-    /* make sure the received grpc-encoding is amongst the ones listed in
-     * grpc-accept-encoding */
-
-    GPR_ASSERT(call->encodings_accepted_by_peer != 0);
-    if (!GPR_BITGET(call->encodings_accepted_by_peer,
-                    call->compression_algorithm)) {
-      extern int grpc_compression_trace;
-      if (grpc_compression_trace) {
-        char *algo_name;
-        grpc_compression_algorithm_name(call->compression_algorithm,
-                                        &algo_name);
-        gpr_log(GPR_ERROR,
-                "Compression algorithm (grpc-encoding = '%s') not present in "
-                "the bitset of accepted encodings (grpc-accept-encodings: "
-                "'0x%x')",
-                algo_name, call->encodings_accepted_by_peer);
-      }
-    }
+    GPR_TIMER_BEGIN("validate_filtered_metadata", 0);
+    validate_filtered_metadata(exec_ctx, bctl);
+    GPR_TIMER_END("validate_filtered_metadata", 0);
+
     if (gpr_time_cmp(md->deadline, gpr_inf_future(md->deadline.clock_type)) !=
             0 &&
         !call->is_client) {
@@ -1245,7 +1378,40 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
           error = GRPC_CALL_ERROR_TOO_MANY_OPERATIONS;
           goto done_with_error;
         }
-        if (op->data.send_initial_metadata.count > INT_MAX) {
+        /* process compression level */
+        grpc_metadata compression_md;
+        memset(&compression_md, 0, sizeof(grpc_metadata));
+        size_t additional_metadata_count = 0;
+        grpc_compression_level effective_compression_level;
+        bool level_set = false;
+        if (op->data.send_initial_metadata.maybe_compression_level.is_set) {
+          effective_compression_level =
+              op->data.send_initial_metadata.maybe_compression_level.level;
+          level_set = true;
+        } else {
+          const grpc_compression_options copts =
+              grpc_channel_compression_options(call->channel);
+          level_set = copts.default_level.is_set;
+          if (level_set) {
+            effective_compression_level = copts.default_level.level;
+          }
+        }
+        if (level_set && !call->is_client) {
+          const grpc_compression_algorithm calgo =
+              compression_algorithm_for_level_locked(
+                  call, effective_compression_level);
+          char *calgo_name;
+          grpc_compression_algorithm_name(calgo, &calgo_name);
+          // the following will be picked up by the compress filter and used as
+          // the call's compression algorithm.
+          compression_md.key = GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY;
+          compression_md.value = calgo_name;
+          compression_md.value_length = strlen(calgo_name);
+          additional_metadata_count++;
+        }
+
+        if (op->data.send_initial_metadata.count + additional_metadata_count >
+            INT_MAX) {
           error = GRPC_CALL_ERROR_INVALID_METADATA;
           goto done_with_error;
         }
@@ -1253,7 +1419,8 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         call->sent_initial_metadata = 1;
         if (!prepare_application_metadata(
                 call, (int)op->data.send_initial_metadata.count,
-                op->data.send_initial_metadata.metadata, 0, call->is_client)) {
+                op->data.send_initial_metadata.metadata, 0, call->is_client,
+                &compression_md, (int)additional_metadata_count)) {
           error = GRPC_CALL_ERROR_INVALID_METADATA;
           goto done_with_error;
         }
@@ -1341,7 +1508,8 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         if (!prepare_application_metadata(
                 call,
                 (int)op->data.send_status_from_server.trailing_metadata_count,
-                op->data.send_status_from_server.trailing_metadata, 1, 1)) {
+                op->data.send_status_from_server.trailing_metadata, 1, 1, NULL,
+                0)) {
           error = GRPC_CALL_ERROR_INVALID_METADATA;
           goto done_with_error;
         }
@@ -1530,9 +1698,10 @@ uint8_t grpc_call_is_client(grpc_call *call) { return call->is_client; }
 grpc_compression_algorithm grpc_call_compression_for_level(
     grpc_call *call, grpc_compression_level level) {
   gpr_mu_lock(&call->mu);
-  const uint32_t accepted_encodings = call->encodings_accepted_by_peer;
+  grpc_compression_algorithm algo =
+      compression_algorithm_for_level_locked(call, level);
   gpr_mu_unlock(&call->mu);
-  return grpc_compression_algorithm_for_level(level, accepted_encodings);
+  return algo;
 }
 
 const char *grpc_call_error_to_string(grpc_call_error error) {
diff --git a/src/core/lib/surface/channel.c b/src/core/lib/surface/channel.c
index a7ea6fa1f0..f0b3c2e15d 100644
--- a/src/core/lib/surface/channel.c
+++ b/src/core/lib/surface/channel.c
@@ -36,16 +36,17 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <grpc/compression.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/iomgr.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/surface/channel_init.h"
-#include "src/core/lib/surface/init.h"
 #include "src/core/lib/transport/static_metadata.h"
 
 /** Cache grpc-status: X mdelems for X = 0..NUM_CACHED_STATUS_ELEMS.
@@ -64,10 +65,12 @@ typedef struct registered_call {
 struct grpc_channel {
   int is_client;
   uint32_t max_message_length;
+  grpc_compression_options compression_options;
   grpc_mdelem *default_authority;
 
   gpr_mu registered_call_mu;
   registered_call *registered_calls;
+
   char *target;
 };
 
@@ -111,6 +114,7 @@ grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
   channel->registered_calls = NULL;
 
   channel->max_message_length = DEFAULT_MAX_MESSAGE_LENGTH;
+  grpc_compression_options_init(&channel->compression_options);
   if (args) {
     for (size_t i = 0; i < args->num_args; i++) {
       if (0 == strcmp(args->args[i].key, GRPC_ARG_MAX_MESSAGE_LENGTH)) {
@@ -151,6 +155,27 @@ grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
                 ":authority", args->args[i].value.string);
           }
         }
+      } else if (0 == strcmp(args->args[i].key,
+                             GRPC_COMPRESSION_CHANNEL_DEFAULT_LEVEL)) {
+        channel->compression_options.default_level.is_set = true;
+        GPR_ASSERT(args->args[i].value.integer >= 0 &&
+                   args->args[i].value.integer < GRPC_COMPRESS_LEVEL_COUNT);
+        channel->compression_options.default_level.level =
+            (grpc_compression_level)args->args[i].value.integer;
+      } else if (0 == strcmp(args->args[i].key,
+                             GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM)) {
+        channel->compression_options.default_algorithm.is_set = true;
+        GPR_ASSERT(args->args[i].value.integer >= 0 &&
+                   args->args[i].value.integer <
+                       GRPC_COMPRESS_ALGORITHMS_COUNT);
+        channel->compression_options.default_algorithm.algorithm =
+            (grpc_compression_algorithm)args->args[i].value.integer;
+      } else if (0 ==
+                 strcmp(args->args[i].key,
+                        GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET)) {
+        channel->compression_options.enabled_algorithms_bitset =
+            (uint32_t)args->args[i].value.integer |
+            0x1; /* always support no compression */
       }
     }
     grpc_channel_args_destroy(args);
@@ -324,6 +349,11 @@ grpc_channel_stack *grpc_channel_get_channel_stack(grpc_channel *channel) {
   return CHANNEL_STACK_FROM_CHANNEL(channel);
 }
 
+grpc_compression_options grpc_channel_compression_options(
+    const grpc_channel *channel) {
+  return channel->compression_options;
+}
+
 grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel, int i) {
   char tmp[GPR_LTOA_MIN_BUFSIZE];
   switch (i) {
diff --git a/src/core/lib/surface/channel.h b/src/core/lib/surface/channel.h
index ff3debc31f..7eff7b8883 100644
--- a/src/core/lib/surface/channel.h
+++ b/src/core/lib/surface/channel.h
@@ -76,4 +76,8 @@ void grpc_channel_internal_unref(grpc_exec_ctx *exec_ctx,
   grpc_channel_internal_unref(exec_ctx, channel)
 #endif
 
+/** Return the channel's compression options. */
+grpc_compression_options grpc_channel_compression_options(
+    const grpc_channel *channel);
+
 #endif /* GRPC_CORE_LIB_SURFACE_CHANNEL_H */
diff --git a/src/cpp/client/client_context.cc b/src/cpp/client/client_context.cc
index 32c7794ade..d3e5ce0c4a 100644
--- a/src/cpp/client/client_context.cc
+++ b/src/cpp/client/client_context.cc
@@ -33,15 +33,14 @@
 
 #include <grpc++/client_context.h>
 
-#include <grpc++/security/credentials.h>
-#include <grpc++/server_context.h>
-#include <grpc++/support/time.h>
 #include <grpc/compression.h>
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/lib/channel/compress_filter.h"
+#include <grpc++/security/credentials.h>
+#include <grpc++/server_context.h>
+#include <grpc++/support/time.h>
 
 namespace grpc {
 
@@ -112,7 +111,7 @@ void ClientContext::set_compression_algorithm(
     abort();
   }
   GPR_ASSERT(algorithm_name != nullptr);
-  AddMetadata(GRPC_COMPRESS_REQUEST_ALGORITHM_KEY, algorithm_name);
+  AddMetadata(GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY, algorithm_name);
 }
 
 void ClientContext::TryCancel() {
diff --git a/src/cpp/client/create_channel_posix.cc b/src/cpp/client/create_channel_posix.cc
new file mode 100644
index 0000000000..60cfed3d62
--- /dev/null
+++ b/src/cpp/client/create_channel_posix.cc
@@ -0,0 +1,56 @@
+/*
+ *
+ * Copyright 2016, 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++/channel.h>
+#include <grpc++/create_channel.h>
+#include <grpc++/impl/grpc_library.h>
+#include <grpc/grpc.h>
+#include <grpc/grpc_posix.h>
+
+#include "src/cpp/client/create_channel_internal.h"
+
+namespace grpc {
+
+#ifdef GPR_SUPPORT_CHANNELS_FROM_FD
+
+std::shared_ptr<Channel> CreateInsecureChannelFromFd(const grpc::string& target,
+                                                     int fd) {
+  internal::GrpcLibrary init_lib;
+  init_lib.init();
+  return CreateChannelInternal(
+      "", grpc_insecure_channel_create_from_fd(target.c_str(), fd, nullptr));
+}
+
+#endif  // GPR_SUPPORT_CHANNELS_FROM_FD
+
+}  // namespace grpc
diff --git a/src/cpp/server/server.cc b/src/cpp/server/server.cc
index f6c3e5747c..50fc4733a1 100644
--- a/src/cpp/server/server.cc
+++ b/src/cpp/server/server.cc
@@ -329,6 +329,10 @@ void Server::SetGlobalCallbacks(GlobalCallbacks* callbacks) {
   g_callbacks.reset(callbacks);
 }
 
+grpc_server* Server::c_server() { return server_; }
+
+CompletionQueue* Server::completion_queue() { return &cq_; }
+
 static grpc_server_register_method_payload_handling PayloadHandlingForMethod(
     RpcServiceMethod* method) {
   switch (method->method_type()) {
diff --git a/src/cpp/server/server_builder.cc b/src/cpp/server/server_builder.cc
index 54feac3982..279981744a 100644
--- a/src/cpp/server/server_builder.cc
+++ b/src/cpp/server/server_builder.cc
@@ -37,6 +37,8 @@
 #include <grpc++/server.h>
 #include <grpc/support/cpu.h>
 #include <grpc/support/log.h>
+
+#include "include/grpc/support/useful.h"
 #include "src/cpp/server/thread_pool_interface.h"
 
 namespace grpc {
@@ -52,12 +54,18 @@ static void do_plugin_list_init(void) {
 
 ServerBuilder::ServerBuilder()
     : max_message_size_(-1), generic_service_(nullptr) {
-  grpc_compression_options_init(&compression_options_);
   gpr_once_init(&once_init_plugin_list, do_plugin_list_init);
   for (auto factory : (*g_plugin_factory_list)) {
     std::unique_ptr<ServerBuilderPlugin> plugin = factory();
     plugins_[plugin->name()] = std::move(plugin);
   }
+  // all compression algorithms enabled by default.
+  enabled_compression_algorithms_bitset_ =
+      (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
+  memset(&maybe_default_compression_level_, 0,
+         sizeof(maybe_default_compression_level_));
+  memset(&maybe_default_compression_algorithm_, 0,
+         sizeof(maybe_default_compression_algorithm_));
 }
 
 std::unique_ptr<ServerCompletionQueue> ServerBuilder::AddCompletionQueue(
@@ -67,35 +75,65 @@ std::unique_ptr<ServerCompletionQueue> ServerBuilder::AddCompletionQueue(
   return std::unique_ptr<ServerCompletionQueue>(cq);
 }
 
-void ServerBuilder::RegisterService(Service* service) {
+ServerBuilder& ServerBuilder::RegisterService(Service* service) {
   services_.emplace_back(new NamedService(service));
+  return *this;
 }
 
-void ServerBuilder::RegisterService(const grpc::string& addr,
-                                    Service* service) {
+ServerBuilder& ServerBuilder::RegisterService(const grpc::string& addr,
+                                              Service* service) {
   services_.emplace_back(new NamedService(addr, service));
+  return *this;
 }
 
-void ServerBuilder::RegisterAsyncGenericService(AsyncGenericService* service) {
+ServerBuilder& ServerBuilder::RegisterAsyncGenericService(
+    AsyncGenericService* service) {
   if (generic_service_) {
     gpr_log(GPR_ERROR,
             "Adding multiple AsyncGenericService is unsupported for now. "
             "Dropping the service %p",
             service);
-    return;
+  } else {
+    generic_service_ = service;
   }
-  generic_service_ = service;
+  return *this;
 }
 
-void ServerBuilder::SetOption(std::unique_ptr<ServerBuilderOption> option) {
+ServerBuilder& ServerBuilder::SetOption(
+    std::unique_ptr<ServerBuilderOption> option) {
   options_.push_back(std::move(option));
+  return *this;
+}
+
+ServerBuilder& ServerBuilder::SetCompressionAlgorithmSupportStatus(
+    grpc_compression_algorithm algorithm, bool enabled) {
+  if (enabled) {
+    GPR_BITSET(&enabled_compression_algorithms_bitset_, algorithm);
+  } else {
+    GPR_BITCLEAR(&enabled_compression_algorithms_bitset_, algorithm);
+  }
+  return *this;
 }
 
-void ServerBuilder::AddListeningPort(const grpc::string& addr,
-                                     std::shared_ptr<ServerCredentials> creds,
-                                     int* selected_port) {
+ServerBuilder& ServerBuilder::SetDefaultCompressionLevel(
+    grpc_compression_level level) {
+  maybe_default_compression_level_.level = level;
+  return *this;
+}
+
+ServerBuilder& ServerBuilder::SetDefaultCompressionAlgorithm(
+    grpc_compression_algorithm algorithm) {
+  maybe_default_compression_algorithm_.is_set = true;
+  maybe_default_compression_algorithm_.algorithm = algorithm;
+  return *this;
+}
+
+ServerBuilder& ServerBuilder::AddListeningPort(
+    const grpc::string& addr, std::shared_ptr<ServerCredentials> creds,
+    int* selected_port) {
   Port port = {addr, creds, selected_port};
   ports_.push_back(port);
+  return *this;
 }
 
 std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
@@ -128,7 +166,15 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
     args.SetInt(GRPC_ARG_MAX_MESSAGE_LENGTH, max_message_size_);
   }
   args.SetInt(GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET,
-              compression_options_.enabled_algorithms_bitset);
+              enabled_compression_algorithms_bitset_);
+  if (maybe_default_compression_level_.is_set) {
+    args.SetInt(GRPC_COMPRESSION_CHANNEL_DEFAULT_LEVEL,
+                maybe_default_compression_level_.level);
+  }
+  if (maybe_default_compression_algorithm_.is_set) {
+    args.SetInt(GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM,
+                maybe_default_compression_algorithm_.algorithm);
+  }
   std::unique_ptr<Server> server(
       new Server(thread_pool.release(), true, max_message_size_, &args));
   ServerInitializer* initializer = server->initializer();
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
index 204fef1b09..43117fd1e9 100644
--- a/src/cpp/server/server_context.cc
+++ b/src/cpp/server/server_context.cc
@@ -42,7 +42,6 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
-#include "src/core/lib/channel/compress_filter.h"
 #include "src/core/lib/surface/call.h"
 
 namespace grpc {
@@ -196,6 +195,9 @@ bool ServerContext::IsCancelled() const {
 }
 
 void ServerContext::set_compression_level(grpc_compression_level level) {
+  // TODO(dgq): get rid of grpc_call_compression_for_level and propagate the
+  // compression level by adding a new argument to
+  // CallOpSendInitialMetadata::SendInitialMetadata.
   const grpc_compression_algorithm algorithm_for_level =
       grpc_call_compression_for_level(call_, level);
   set_compression_algorithm(algorithm_for_level);
@@ -210,7 +212,7 @@ void ServerContext::set_compression_algorithm(
     abort();
   }
   GPR_ASSERT(algorithm_name != NULL);
-  AddInitialMetadata(GRPC_COMPRESS_REQUEST_ALGORITHM_KEY, algorithm_name);
+  AddInitialMetadata(GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY, algorithm_name);
 }
 
 grpc::string ServerContext::peer() const {
diff --git a/src/cpp/server/server_posix.cc b/src/cpp/server/server_posix.cc
new file mode 100644
index 0000000000..8cb9753a12
--- /dev/null
+++ b/src/cpp/server/server_posix.cc
@@ -0,0 +1,49 @@
+/*
+ *
+ * Copyright 2016, 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++/server_posix.h>
+
+#include <grpc/grpc_posix.h>
+
+namespace grpc {
+
+#ifdef GPR_SUPPORT_CHANNELS_FROM_FD
+
+void AddInsecureChannelFromFd(Server* server, int fd) {
+  grpc_server_add_insecure_channel_from_fd(
+      server->c_server(), server->completion_queue()->cq(), fd);
+
+#endif  // GPR_SUPPORT_CHANNELS_FROM_FD
+}
+
+}  // namespace grpc
diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index 2a243b94cb..4782654250 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -503,6 +503,7 @@ grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
                            grpc_metadata_array *initial_metadata, uint32_t write_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[6];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -555,6 +556,7 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[4];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -596,6 +598,7 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
     size_t send_buffer_len, grpc_metadata_array *initial_metadata, uint32_t write_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[4];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -638,6 +641,7 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[2];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -684,6 +688,7 @@ grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
                             int32_t send_empty_initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[2];
+  memset(ops, 0, sizeof(ops));
   size_t nops = send_empty_initial_metadata ? 2 : 1;
   ops[0].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
@@ -691,8 +696,6 @@ grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
   ops[0].flags = write_flags;
   ops[0].reserved = NULL;
   ops[1].op = GRPC_OP_SEND_INITIAL_METADATA;
-  ops[1].data.send_initial_metadata.count = 0;
-  ops[1].data.send_initial_metadata.metadata = NULL;
   ops[1].flags = 0;
   ops[1].reserved = NULL;
 
@@ -719,6 +722,7 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
     size_t optional_send_buffer_len, uint32_t write_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[3];
+  memset(ops, 0, sizeof(ops));
   size_t nops = 1;
   ops[0].op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   ops[0].data.send_status_from_server.status = status_code;
@@ -743,8 +747,6 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
   }
   if (send_empty_initial_metadata) {
     ops[nops].op = GRPC_OP_SEND_INITIAL_METADATA;
-    ops[nops].data.send_initial_metadata.count = 0;
-    ops[nops].data.send_initial_metadata.metadata = NULL;
     ops[nops].flags = 0;
     ops[nops].reserved = NULL;
     nops++;
@@ -784,6 +786,7 @@ grpcsharp_call_send_initial_metadata(grpc_call *call,
                                      grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[1];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
diff --git a/src/objective-c/GRPCClient/private/GRPCWrappedCall.m b/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
index 16e5bff7ff..a3fa5938cd 100644
--- a/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
+++ b/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
@@ -72,6 +72,8 @@
     _op.op = GRPC_OP_SEND_INITIAL_METADATA;
     _op.data.send_initial_metadata.count = metadata.count;
     _op.data.send_initial_metadata.metadata = metadata.grpc_metadataArray;
+    _op.data.send_initial_metadata.maybe_compression_level.is_set = false;
+    _op.data.send_initial_metadata.maybe_compression_level.level = 0;
     _handler = handler;
   }
   return self;
diff --git a/src/php/ext/grpc/call.c b/src/php/ext/grpc/call.c
index 884130e7d4..0ec502262d 100644
--- a/src/php/ext/grpc/call.c
+++ b/src/php/ext/grpc/call.c
@@ -292,6 +292,7 @@ PHP_METHOD(Call, startBatch) {
   grpc_metadata_array_init(&recv_trailing_metadata);
   MAKE_STD_ZVAL(result);
   object_init(result);
+  memset(ops, 0, sizeof(ops));
   /* "a" == 1 array */
   if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &array) ==
       FAILURE) {
diff --git a/src/python/grpcio/grpc/_cython/imports.generated.c b/src/python/grpcio/grpc/_cython/imports.generated.c
index c80ee66c06..5c49f6cf3e 100644
--- a/src/python/grpcio/grpc/_cython/imports.generated.c
+++ b/src/python/grpcio/grpc/_cython/imports.generated.c
@@ -126,6 +126,8 @@ grpc_header_key_is_legal_type grpc_header_key_is_legal_import;
 grpc_header_nonbin_value_is_legal_type grpc_header_nonbin_value_is_legal_import;
 grpc_is_binary_header_type grpc_is_binary_header_import;
 grpc_call_error_to_string_type grpc_call_error_to_string_import;
+grpc_insecure_channel_create_from_fd_type grpc_insecure_channel_create_from_fd_import;
+grpc_server_add_insecure_channel_from_fd_type grpc_server_add_insecure_channel_from_fd_import;
 grpc_auth_property_iterator_next_type grpc_auth_property_iterator_next_import;
 grpc_auth_context_property_iterator_type grpc_auth_context_property_iterator_import;
 grpc_auth_context_peer_identity_type grpc_auth_context_peer_identity_import;
@@ -397,6 +399,8 @@ void pygrpc_load_imports(HMODULE library) {
   grpc_header_nonbin_value_is_legal_import = (grpc_header_nonbin_value_is_legal_type) GetProcAddress(library, "grpc_header_nonbin_value_is_legal");
   grpc_is_binary_header_import = (grpc_is_binary_header_type) GetProcAddress(library, "grpc_is_binary_header");
   grpc_call_error_to_string_import = (grpc_call_error_to_string_type) GetProcAddress(library, "grpc_call_error_to_string");
+  grpc_insecure_channel_create_from_fd_import = (grpc_insecure_channel_create_from_fd_type) GetProcAddress(library, "grpc_insecure_channel_create_from_fd");
+  grpc_server_add_insecure_channel_from_fd_import = (grpc_server_add_insecure_channel_from_fd_type) GetProcAddress(library, "grpc_server_add_insecure_channel_from_fd");
   grpc_auth_property_iterator_next_import = (grpc_auth_property_iterator_next_type) GetProcAddress(library, "grpc_auth_property_iterator_next");
   grpc_auth_context_property_iterator_import = (grpc_auth_context_property_iterator_type) GetProcAddress(library, "grpc_auth_context_property_iterator");
   grpc_auth_context_peer_identity_import = (grpc_auth_context_peer_identity_type) GetProcAddress(library, "grpc_auth_context_peer_identity");
diff --git a/src/python/grpcio/grpc/_cython/imports.generated.h b/src/python/grpcio/grpc/_cython/imports.generated.h
index 7b8e98d9bf..16bb5cdfab 100644
--- a/src/python/grpcio/grpc/_cython/imports.generated.h
+++ b/src/python/grpcio/grpc/_cython/imports.generated.h
@@ -43,6 +43,7 @@
 #include <grpc/census.h>
 #include <grpc/compression.h>
 #include <grpc/grpc.h>
+#include <grpc/grpc_posix.h>
 #include <grpc/grpc_security.h>
 #include <grpc/impl/codegen/alloc.h>
 #include <grpc/impl/codegen/byte_buffer.h>
@@ -328,6 +329,12 @@ extern grpc_is_binary_header_type grpc_is_binary_header_import;
 typedef const char *(*grpc_call_error_to_string_type)(grpc_call_error error);
 extern grpc_call_error_to_string_type grpc_call_error_to_string_import;
 #define grpc_call_error_to_string grpc_call_error_to_string_import
+typedef grpc_channel *(*grpc_insecure_channel_create_from_fd_type)(const char *target, int fd, const grpc_channel_args *args);
+extern grpc_insecure_channel_create_from_fd_type grpc_insecure_channel_create_from_fd_import;
+#define grpc_insecure_channel_create_from_fd grpc_insecure_channel_create_from_fd_import
+typedef void(*grpc_server_add_insecure_channel_from_fd_type)(grpc_server *server, grpc_completion_queue *cq, int fd);
+extern grpc_server_add_insecure_channel_from_fd_type grpc_server_add_insecure_channel_from_fd_import;
+#define grpc_server_add_insecure_channel_from_fd grpc_server_add_insecure_channel_from_fd_import
 typedef const grpc_auth_property *(*grpc_auth_property_iterator_next_type)(grpc_auth_property_iterator *it);
 extern grpc_auth_property_iterator_next_type grpc_auth_property_iterator_next_import;
 #define grpc_auth_property_iterator_next grpc_auth_property_iterator_next_import
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index cfc083cf11..2a5229434c 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -84,7 +84,7 @@ CORE_SOURCE_FILES = [
   'src/core/lib/channel/connected_channel.c',
   'src/core/lib/channel/http_client_filter.c',
   'src/core/lib/channel/http_server_filter.c',
-  'src/core/lib/compression/compression_algorithm.c',
+  'src/core/lib/compression/compression.c',
   'src/core/lib/compression/message_compress.c',
   'src/core/lib/debug/trace.c',
   'src/core/lib/http/format_request.c',
@@ -232,7 +232,9 @@ CORE_SOURCE_FILES = [
   'src/core/ext/client_config/subchannel_index.c',
   'src/core/ext/client_config/uri_parser.c',
   'src/core/ext/transport/chttp2/server/insecure/server_chttp2.c',
+  'src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c',
   'src/core/ext/transport/chttp2/client/insecure/channel_create.c',
+  'src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c',
   'src/core/ext/lb_policy/grpclb/load_balancer_api.c',
   'src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c',
   'third_party/nanopb/pb_common.c',
diff --git a/src/ruby/ext/grpc/rb_grpc_imports.generated.c b/src/ruby/ext/grpc/rb_grpc_imports.generated.c
index f76462649d..c13d1a00d7 100644
--- a/src/ruby/ext/grpc/rb_grpc_imports.generated.c
+++ b/src/ruby/ext/grpc/rb_grpc_imports.generated.c
@@ -126,6 +126,8 @@ grpc_header_key_is_legal_type grpc_header_key_is_legal_import;
 grpc_header_nonbin_value_is_legal_type grpc_header_nonbin_value_is_legal_import;
 grpc_is_binary_header_type grpc_is_binary_header_import;
 grpc_call_error_to_string_type grpc_call_error_to_string_import;
+grpc_insecure_channel_create_from_fd_type grpc_insecure_channel_create_from_fd_import;
+grpc_server_add_insecure_channel_from_fd_type grpc_server_add_insecure_channel_from_fd_import;
 grpc_auth_property_iterator_next_type grpc_auth_property_iterator_next_import;
 grpc_auth_context_property_iterator_type grpc_auth_context_property_iterator_import;
 grpc_auth_context_peer_identity_type grpc_auth_context_peer_identity_import;
@@ -393,6 +395,8 @@ void grpc_rb_load_imports(HMODULE library) {
   grpc_header_nonbin_value_is_legal_import = (grpc_header_nonbin_value_is_legal_type) GetProcAddress(library, "grpc_header_nonbin_value_is_legal");
   grpc_is_binary_header_import = (grpc_is_binary_header_type) GetProcAddress(library, "grpc_is_binary_header");
   grpc_call_error_to_string_import = (grpc_call_error_to_string_type) GetProcAddress(library, "grpc_call_error_to_string");
+  grpc_insecure_channel_create_from_fd_import = (grpc_insecure_channel_create_from_fd_type) GetProcAddress(library, "grpc_insecure_channel_create_from_fd");
+  grpc_server_add_insecure_channel_from_fd_import = (grpc_server_add_insecure_channel_from_fd_type) GetProcAddress(library, "grpc_server_add_insecure_channel_from_fd");
   grpc_auth_property_iterator_next_import = (grpc_auth_property_iterator_next_type) GetProcAddress(library, "grpc_auth_property_iterator_next");
   grpc_auth_context_property_iterator_import = (grpc_auth_context_property_iterator_type) GetProcAddress(library, "grpc_auth_context_property_iterator");
   grpc_auth_context_peer_identity_import = (grpc_auth_context_peer_identity_type) GetProcAddress(library, "grpc_auth_context_peer_identity");
diff --git a/src/ruby/ext/grpc/rb_grpc_imports.generated.h b/src/ruby/ext/grpc/rb_grpc_imports.generated.h
index 5d690a915d..9c86a3690c 100644
--- a/src/ruby/ext/grpc/rb_grpc_imports.generated.h
+++ b/src/ruby/ext/grpc/rb_grpc_imports.generated.h
@@ -43,6 +43,7 @@
 #include <grpc/census.h>
 #include <grpc/compression.h>
 #include <grpc/grpc.h>
+#include <grpc/grpc_posix.h>
 #include <grpc/grpc_security.h>
 #include <grpc/impl/codegen/alloc.h>
 #include <grpc/impl/codegen/byte_buffer.h>
@@ -328,6 +329,12 @@ extern grpc_is_binary_header_type grpc_is_binary_header_import;
 typedef const char *(*grpc_call_error_to_string_type)(grpc_call_error error);
 extern grpc_call_error_to_string_type grpc_call_error_to_string_import;
 #define grpc_call_error_to_string grpc_call_error_to_string_import
+typedef grpc_channel *(*grpc_insecure_channel_create_from_fd_type)(const char *target, int fd, const grpc_channel_args *args);
+extern grpc_insecure_channel_create_from_fd_type grpc_insecure_channel_create_from_fd_import;
+#define grpc_insecure_channel_create_from_fd grpc_insecure_channel_create_from_fd_import
+typedef void(*grpc_server_add_insecure_channel_from_fd_type)(grpc_server *server, grpc_completion_queue *cq, int fd);
+extern grpc_server_add_insecure_channel_from_fd_type grpc_server_add_insecure_channel_from_fd_import;
+#define grpc_server_add_insecure_channel_from_fd grpc_server_add_insecure_channel_from_fd_import
 typedef const grpc_auth_property *(*grpc_auth_property_iterator_next_type)(grpc_auth_property_iterator *it);
 extern grpc_auth_property_iterator_next_type grpc_auth_property_iterator_next_import;
 #define grpc_auth_property_iterator_next grpc_auth_property_iterator_next_import