Merge branch 'master' of github.com:grpc/grpc into lr_hook

12 files changed, 257 insertions, 141 deletions

diff --git a/src/core/ext/client_config/client_channel.c b/src/core/ext/client_config/client_channel.c
index 3ec0ab4387..095f3d81e7 100644
--- a/src/core/ext/client_config/client_channel.c
+++ b/src/core/ext/client_config/client_channel.c
@@ -205,7 +205,11 @@ static void cc_on_config_changed(grpc_exec_ctx *exec_ctx, void *arg,
   gpr_mu_lock(&chand->mu_config);
   old_lb_policy = chand->lb_policy;
   chand->lb_policy = lb_policy;
-  if (lb_policy != NULL || chand->resolver == NULL /* disconnected */) {
+  if (lb_policy != NULL) {
+    grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
+                               NULL);
+  } else if (chand->resolver == NULL /* disconnected */) {
+    grpc_closure_list_fail_all(&chand->waiting_for_config_closures);
     grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
                                NULL);
   }
@@ -293,6 +297,11 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
     grpc_resolver_shutdown(exec_ctx, chand->resolver);
     GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel");
     chand->resolver = NULL;
+    if (!chand->started_resolving) {
+      grpc_closure_list_fail_all(&chand->waiting_for_config_closures);
+      grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
+                                 NULL);
+    }
     if (chand->lb_policy != NULL) {
       grpc_pollset_set_del_pollset_set(exec_ctx,
                                        chand->lb_policy->interested_parties,
@@ -321,10 +330,10 @@ static int cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *arg,
 
 static void continue_picking(grpc_exec_ctx *exec_ctx, void *arg, bool success) {
   continue_picking_args *cpa = arg;
-  if (!success) {
-    grpc_exec_ctx_enqueue(exec_ctx, cpa->on_ready, false, NULL);
-  } else if (cpa->connected_subchannel == NULL) {
+  if (cpa->connected_subchannel == NULL) {
     /* cancelled, do nothing */
+  } else if (!success) {
+    grpc_exec_ctx_enqueue(exec_ctx, cpa->on_ready, false, NULL);
   } else if (cc_pick_subchannel(exec_ctx, cpa->elem, cpa->initial_metadata,
                                 cpa->initial_metadata_flags,
                                 cpa->connected_subchannel, cpa->on_ready)) {
@@ -381,14 +390,19 @@ static int cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp,
                        &chand->incoming_configuration,
                        &chand->on_config_changed);
   }
-  cpa = gpr_malloc(sizeof(*cpa));
-  cpa->initial_metadata = initial_metadata;
-  cpa->initial_metadata_flags = initial_metadata_flags;
-  cpa->connected_subchannel = connected_subchannel;
-  cpa->on_ready = on_ready;
-  cpa->elem = elem;
-  grpc_closure_init(&cpa->closure, continue_picking, cpa);
-  grpc_closure_list_add(&chand->waiting_for_config_closures, &cpa->closure, 1);
+  if (chand->resolver != NULL) {
+    cpa = gpr_malloc(sizeof(*cpa));
+    cpa->initial_metadata = initial_metadata;
+    cpa->initial_metadata_flags = initial_metadata_flags;
+    cpa->connected_subchannel = connected_subchannel;
+    cpa->on_ready = on_ready;
+    cpa->elem = elem;
+    grpc_closure_init(&cpa->closure, continue_picking, cpa);
+    grpc_closure_list_add(&chand->waiting_for_config_closures, &cpa->closure,
+                          1);
+  } else {
+    grpc_exec_ctx_enqueue(exec_ctx, on_ready, false, NULL);
+  }
   gpr_mu_unlock(&chand->mu_config);
   return 0;
 }
diff --git a/src/core/ext/client_config/parse_address.c b/src/core/ext/client_config/parse_address.c
new file mode 100644
index 0000000000..8b4abe24a6
--- /dev/null
+++ b/src/core/ext/client_config/parse_address.c
@@ -0,0 +1,137 @@
+/*
+ *
+ * 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 "src/core/ext/client_config/parse_address.h"
+
+#include <stdio.h>
+#include <string.h>
+#ifdef GPR_HAVE_UNIX_SOCKET
+#include <sys/un.h>
+#endif
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/host_port.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+
+#ifdef GPR_HAVE_UNIX_SOCKET
+int parse_unix(grpc_uri *uri, struct sockaddr_storage *addr, size_t *len) {
+  struct sockaddr_un *un = (struct sockaddr_un *)addr;
+
+  un->sun_family = AF_UNIX;
+  strcpy(un->sun_path, uri->path);
+  *len = strlen(un->sun_path) + sizeof(un->sun_family) + 1;
+
+  return 1;
+}
+#endif
+
+int parse_ipv4(grpc_uri *uri, struct sockaddr_storage *addr, size_t *len) {
+  const char *host_port = uri->path;
+  char *host;
+  char *port;
+  int port_num;
+  int result = 0;
+  struct sockaddr_in *in = (struct sockaddr_in *)addr;
+
+  if (*host_port == '/') ++host_port;
+  if (!gpr_split_host_port(host_port, &host, &port)) {
+    return 0;
+  }
+
+  memset(in, 0, sizeof(*in));
+  *len = sizeof(*in);
+  in->sin_family = AF_INET;
+  if (inet_pton(AF_INET, host, &in->sin_addr) == 0) {
+    gpr_log(GPR_ERROR, "invalid ipv4 address: '%s'", host);
+    goto done;
+  }
+
+  if (port != NULL) {
+    if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 ||
+        port_num > 65535) {
+      gpr_log(GPR_ERROR, "invalid ipv4 port: '%s'", port);
+      goto done;
+    }
+    in->sin_port = htons((uint16_t)port_num);
+  } else {
+    gpr_log(GPR_ERROR, "no port given for ipv4 scheme");
+    goto done;
+  }
+
+  result = 1;
+done:
+  gpr_free(host);
+  gpr_free(port);
+  return result;
+}
+
+int parse_ipv6(grpc_uri *uri, struct sockaddr_storage *addr, size_t *len) {
+  const char *host_port = uri->path;
+  char *host;
+  char *port;
+  int port_num;
+  int result = 0;
+  struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)addr;
+
+  if (*host_port == '/') ++host_port;
+  if (!gpr_split_host_port(host_port, &host, &port)) {
+    return 0;
+  }
+
+  memset(in6, 0, sizeof(*in6));
+  *len = sizeof(*in6);
+  in6->sin6_family = AF_INET6;
+  if (inet_pton(AF_INET6, host, &in6->sin6_addr) == 0) {
+    gpr_log(GPR_ERROR, "invalid ipv6 address: '%s'", host);
+    goto done;
+  }
+
+  if (port != NULL) {
+    if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 ||
+        port_num > 65535) {
+      gpr_log(GPR_ERROR, "invalid ipv6 port: '%s'", port);
+      goto done;
+    }
+    in6->sin6_port = htons((uint16_t)port_num);
+  } else {
+    gpr_log(GPR_ERROR, "no port given for ipv6 scheme");
+    goto done;
+  }
+
+  result = 1;
+done:
+  gpr_free(host);
+  gpr_free(port);
+  return result;
+}
diff --git a/src/core/ext/client_config/parse_address.h b/src/core/ext/client_config/parse_address.h
new file mode 100644
index 0000000000..74c86f4d93
--- /dev/null
+++ b/src/core/ext/client_config/parse_address.h
@@ -0,0 +1,56 @@
+/*
+ *
+ * Copyright 2015, 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_EXT_CLIENT_CONFIG_PARSE_ADDRESS_H
+#define GRPC_CORE_EXT_CLIENT_CONFIG_PARSE_ADDRESS_H
+
+#include <stddef.h>
+
+#include "src/core/ext/client_config/uri_parser.h"
+#include "src/core/lib/iomgr/sockaddr.h"
+
+#ifdef GPR_HAVE_UNIX_SOCKET
+/** Populate \a addr and \a len from \a uri, whose path is expected to contain a
+ * unix socket path. Returns true upon success. */
+int parse_unix(grpc_uri *uri, struct sockaddr_storage *addr, size_t *len);
+#endif
+
+/** Populate /a addr and \a len from \a uri, whose path is expected to contain a
+ * host:port pair. Returns true upon success. */
+int parse_ipv4(grpc_uri *uri, struct sockaddr_storage *addr, size_t *len);
+
+/** Populate /a addr and \a len from \a uri, whose path is expected to contain a
+ * host:port pair. Returns true upon success. */
+int parse_ipv6(grpc_uri *uri, struct sockaddr_storage *addr, size_t *len);
+
+#endif /* GRPC_CORE_EXT_CLIENT_CONFIG_PARSE_ADDRESS_H */
diff --git a/src/core/ext/client_config/subchannel.c b/src/core/ext/client_config/subchannel.c
index 0aa94ca8fb..4e6ab8d51a 100644
--- a/src/core/ext/client_config/subchannel.c
+++ b/src/core/ext/client_config/subchannel.c
@@ -135,8 +135,6 @@ struct grpc_subchannel {
   int have_alarm;
   /** our alarm */
   grpc_timer alarm;
-  /** current random value */
-  uint32_t random;
 };
 
 struct grpc_subchannel_call {
@@ -297,10 +295,6 @@ void grpc_subchannel_weak_unref(grpc_exec_ctx *exec_ctx,
   }
 }
 
-static uint32_t random_seed() {
-  return (uint32_t)(gpr_time_to_millis(gpr_now(GPR_CLOCK_MONOTONIC)));
-}
-
 grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
                                         grpc_connector *connector,
                                         grpc_subchannel_args *args) {
@@ -332,7 +326,6 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
   grpc_set_initial_connect_string(&c->addr, &c->addr_len,
                                   &c->initial_connect_string);
   c->args = grpc_channel_args_copy(args->args);
-  c->random = random_seed();
   c->root_external_state_watcher.next = c->root_external_state_watcher.prev =
       &c->root_external_state_watcher;
   grpc_closure_init(&c->connected, subchannel_connected, c);
diff --git a/src/core/ext/client_config/subchannel_call_holder.c b/src/core/ext/client_config/subchannel_call_holder.c
index 3db462b246..9918fbdcb4 100644
--- a/src/core/ext/client_config/subchannel_call_holder.c
+++ b/src/core/ext/client_config/subchannel_call_holder.c
@@ -252,9 +252,9 @@ char *grpc_subchannel_call_holder_get_peer(
     grpc_exec_ctx *exec_ctx, grpc_subchannel_call_holder *holder) {
   grpc_subchannel_call *subchannel_call = GET_CALL(holder);
 
-  if (subchannel_call) {
-    return grpc_subchannel_call_get_peer(exec_ctx, subchannel_call);
-  } else {
+  if (subchannel_call == NULL || subchannel_call == CANCELLED_CALL) {
     return NULL;
+  } else {
+    return grpc_subchannel_call_get_peer(exec_ctx, subchannel_call);
   }
 }
diff --git a/src/core/ext/lb_policy/pick_first/pick_first.c b/src/core/ext/lb_policy/pick_first/pick_first.c
index 5926f9d70b..0d215cd196 100644
--- a/src/core/ext/lb_policy/pick_first/pick_first.c
+++ b/src/core/ext/lb_policy/pick_first/pick_first.c
@@ -109,7 +109,7 @@ static void pf_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   if (selected != NULL) {
     grpc_connected_subchannel_notify_on_state_change(
         exec_ctx, selected, NULL, NULL, &p->connectivity_changed);
-  } else {
+  } else if (p->num_subchannels > 0) {
     grpc_subchannel_notify_on_state_change(
         exec_ctx, p->subchannels[p->checking_subchannel], NULL, NULL,
         &p->connectivity_changed);
diff --git a/src/core/ext/resolver/dns/native/dns_resolver.c b/src/core/ext/resolver/dns/native/dns_resolver.c
index 2749b0ca01..620ba4e2aa 100644
--- a/src/core/ext/resolver/dns/native/dns_resolver.c
+++ b/src/core/ext/resolver/dns/native/dns_resolver.c
@@ -86,7 +86,8 @@ typedef struct {
 
 static void dns_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *r);
 
-static void dns_start_resolving_locked(dns_resolver *r);
+static void dns_start_resolving_locked(grpc_exec_ctx *exec_ctx,
+                                       dns_resolver *r);
 static void dns_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
                                          dns_resolver *r);
 
@@ -119,7 +120,7 @@ static void dns_channel_saw_error(grpc_exec_ctx *exec_ctx,
   gpr_mu_lock(&r->mu);
   if (!r->resolving) {
     gpr_backoff_reset(&r->backoff_state);
-    dns_start_resolving_locked(r);
+    dns_start_resolving_locked(exec_ctx, r);
   }
   gpr_mu_unlock(&r->mu);
 }
@@ -134,7 +135,7 @@ static void dns_next(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
   r->target_config = target_config;
   if (r->resolved_version == 0 && !r->resolving) {
     gpr_backoff_reset(&r->backoff_state);
-    dns_start_resolving_locked(r);
+    dns_start_resolving_locked(exec_ctx, r);
   } else {
     dns_maybe_finish_next_locked(exec_ctx, r);
   }
@@ -149,7 +150,7 @@ static void dns_on_retry_timer(grpc_exec_ctx *exec_ctx, void *arg,
   r->have_retry_timer = false;
   if (success) {
     if (!r->resolving) {
-      dns_start_resolving_locked(r);
+      dns_start_resolving_locked(exec_ctx, r);
     }
   }
   gpr_mu_unlock(&r->mu);
@@ -201,11 +202,12 @@ static void dns_on_resolved(grpc_exec_ctx *exec_ctx, void *arg,
   GRPC_RESOLVER_UNREF(exec_ctx, &r->base, "dns-resolving");
 }
 
-static void dns_start_resolving_locked(dns_resolver *r) {
+static void dns_start_resolving_locked(grpc_exec_ctx *exec_ctx,
+                                       dns_resolver *r) {
   GRPC_RESOLVER_REF(&r->base, "dns-resolving");
   GPR_ASSERT(!r->resolving);
   r->resolving = 1;
-  grpc_resolve_address(r->name, r->default_port, dns_on_resolved, r);
+  grpc_resolve_address(exec_ctx, r->name, r->default_port, dns_on_resolved, r);
 }
 
 static void dns_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
diff --git a/src/core/ext/resolver/sockaddr/sockaddr_resolver.c b/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
index 1d54a86c39..a4fa9acf22 100644
--- a/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
+++ b/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
@@ -40,11 +40,8 @@
 #include <grpc/support/port_platform.h>
 #include <grpc/support/string_util.h>
 
-#ifdef GPR_HAVE_UNIX_SOCKET
-#include <sys/un.h>
-#endif
-
 #include "src/core/ext/client_config/lb_policy_registry.h"
+#include "src/core/ext/client_config/parse_address.h"
 #include "src/core/ext/client_config/resolver_registry.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
@@ -167,105 +164,12 @@ static char *ipv6_get_default_authority(grpc_resolver_factory *factory,
 }
 
 #ifdef GPR_HAVE_UNIX_SOCKET
-static int parse_unix(grpc_uri *uri, struct sockaddr_storage *addr,
-                      size_t *len) {
-  struct sockaddr_un *un = (struct sockaddr_un *)addr;
-
-  un->sun_family = AF_UNIX;
-  strcpy(un->sun_path, uri->path);
-  *len = strlen(un->sun_path) + sizeof(un->sun_family) + 1;
-
-  return 1;
-}
-
 char *unix_get_default_authority(grpc_resolver_factory *factory,
                                  grpc_uri *uri) {
   return gpr_strdup("localhost");
 }
 #endif
 
-static int parse_ipv4(grpc_uri *uri, struct sockaddr_storage *addr,
-                      size_t *len) {
-  const char *host_port = uri->path;
-  char *host;
-  char *port;
-  int port_num;
-  int result = 0;
-  struct sockaddr_in *in = (struct sockaddr_in *)addr;
-
-  if (*host_port == '/') ++host_port;
-  if (!gpr_split_host_port(host_port, &host, &port)) {
-    return 0;
-  }
-
-  memset(in, 0, sizeof(*in));
-  *len = sizeof(*in);
-  in->sin_family = AF_INET;
-  if (inet_pton(AF_INET, host, &in->sin_addr) == 0) {
-    gpr_log(GPR_ERROR, "invalid ipv4 address: '%s'", host);
-    goto done;
-  }
-
-  if (port != NULL) {
-    if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 ||
-        port_num > 65535) {
-      gpr_log(GPR_ERROR, "invalid ipv4 port: '%s'", port);
-      goto done;
-    }
-    in->sin_port = htons((uint16_t)port_num);
-  } else {
-    gpr_log(GPR_ERROR, "no port given for ipv4 scheme");
-    goto done;
-  }
-
-  result = 1;
-done:
-  gpr_free(host);
-  gpr_free(port);
-  return result;
-}
-
-static int parse_ipv6(grpc_uri *uri, struct sockaddr_storage *addr,
-                      size_t *len) {
-  const char *host_port = uri->path;
-  char *host;
-  char *port;
-  int port_num;
-  int result = 0;
-  struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)addr;
-
-  if (*host_port == '/') ++host_port;
-  if (!gpr_split_host_port(host_port, &host, &port)) {
-    return 0;
-  }
-
-  memset(in6, 0, sizeof(*in6));
-  *len = sizeof(*in6);
-  in6->sin6_family = AF_INET6;
-  if (inet_pton(AF_INET6, host, &in6->sin6_addr) == 0) {
-    gpr_log(GPR_ERROR, "invalid ipv6 address: '%s'", host);
-    goto done;
-  }
-
-  if (port != NULL) {
-    if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 ||
-        port_num > 65535) {
-      gpr_log(GPR_ERROR, "invalid ipv6 port: '%s'", port);
-      goto done;
-    }
-    in6->sin6_port = htons((uint16_t)port_num);
-  } else {
-    gpr_log(GPR_ERROR, "no port given for ipv6 scheme");
-    goto done;
-  }
-
-  result = 1;
-done:
-  gpr_free(host);
-  gpr_free(port);
-  return result;
-}
-
 static void do_nothing(void *ignored) {}
 
 static grpc_resolver *sockaddr_create(
diff --git a/src/core/ext/resolver/zookeeper/zookeeper_resolver.c b/src/core/ext/resolver/zookeeper/zookeeper_resolver.c
index 898632c3cd..deb4b9b1ef 100644
--- a/src/core/ext/resolver/zookeeper/zookeeper_resolver.c
+++ b/src/core/ext/resolver/zookeeper/zookeeper_resolver.c
@@ -299,7 +299,7 @@ static void zookeeper_get_children_node_completion(int rc, const char *value,
   address = zookeeper_parse_address(value, (size_t)value_len);
   if (address != NULL) {
     /** Further resolves address by DNS */
-    grpc_resolve_address(address, NULL, zookeeper_dns_resolved, r);
+    grpc_resolve_address(&exec_ctx, address, NULL, zookeeper_dns_resolved, r);
     gpr_free(address);
   } else {
     gpr_log(GPR_ERROR, "Error in resolving a child node of %s", r->name);
@@ -375,8 +375,10 @@ static void zookeeper_get_node_completion(int rc, const char *value,
     r->resolved_addrs->naddrs = 0;
     r->resolved_total = 1;
     /** Further resolves address by DNS */
-    grpc_resolve_address(address, NULL, zookeeper_dns_resolved, r);
+    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    grpc_resolve_address(&exec_ctx, address, NULL, zookeeper_dns_resolved, r);
     gpr_free(address);
+    grpc_exec_ctx_finish(&exec_ctx);
     return;
   }
 
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create.c b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
index 0ed115793b..c5d3d8d9cc 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create.c
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
@@ -235,5 +235,7 @@ grpc_channel *grpc_insecure_channel_create(const char *target,
 
   grpc_exec_ctx_finish(&exec_ctx);
 
-  return channel; /* may be NULL */
+  return channel != NULL ? channel : grpc_lame_client_channel_create(
+                                         target, GRPC_STATUS_INTERNAL,
+                                         "Failed to create client channel");
 }
diff --git a/src/core/ext/transport/chttp2/transport/bin_encoder.c b/src/core/ext/transport/chttp2/transport/bin_encoder.c
index db68e750ac..1b43c28be1 100644
--- a/src/core/ext/transport/chttp2/transport/bin_encoder.c
+++ b/src/core/ext/transport/chttp2/transport/bin_encoder.c
@@ -194,9 +194,13 @@ gpr_slice grpc_chttp2_base64_encode_and_huffman_compress_impl(gpr_slice input) {
 
   /* encode full triplets */
   for (i = 0; i < input_triplets; i++) {
-    enc_add2(&out, in[0] >> 2, (uint8_t)((in[0] & 0x3) << 4) | (in[1] >> 4));
-    enc_add2(&out, (uint8_t)((in[1] & 0xf) << 2) | (in[2] >> 6),
-             (uint8_t)(in[2] & 0x3f));
+    const uint8_t low_to_high = (uint8_t)((in[0] & 0x3) << 4);
+    const uint8_t high_to_low = in[1] >> 4;
+    enc_add2(&out, in[0] >> 2, low_to_high | high_to_low);
+
+    const uint8_t a = (uint8_t)((in[1] & 0xf) << 2);
+    const uint8_t b = (in[2] >> 6);
+    enc_add2(&out, a | b, in[2] & 0x3f);
     in += 3;
   }
 
@@ -208,12 +212,14 @@ gpr_slice grpc_chttp2_base64_encode_and_huffman_compress_impl(gpr_slice input) {
       enc_add2(&out, in[0] >> 2, (uint8_t)((in[0] & 0x3) << 4));
       in += 1;
       break;
-    case 2:
-      enc_add2(&out, in[0] >> 2,
-               (uint8_t)((in[0] & 0x3) << 4) | (uint8_t)(in[1] >> 4));
+    case 2: {
+      const uint8_t low_to_high = (uint8_t)((in[0] & 0x3) << 4);
+      const uint8_t high_to_low = in[1] >> 4;
+      enc_add2(&out, in[0] >> 2, low_to_high | high_to_low);
       enc_add1(&out, (uint8_t)((in[1] & 0xf) << 2));
       in += 2;
       break;
+    }
   }
 
   if (out.temp_length) {
diff --git a/src/core/ext/transport/chttp2/transport/hpack_parser.c b/src/core/ext/transport/chttp2/transport/hpack_parser.c
index a36d2fc382..687936bfd3 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_parser.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_parser.c
@@ -638,6 +638,10 @@ static int on_hdr(grpc_chttp2_hpack_parser *p, grpc_mdelem *md,
       return 0;
     }
   }
+  if (p->on_header == NULL) {
+    GRPC_MDELEM_UNREF(md);
+    return 0;
+  }
   p->on_header(p->on_header_user_data, md);
   return 1;
 }
@@ -1382,12 +1386,8 @@ static int parse_value_string_with_literal_key(grpc_chttp2_hpack_parser *p,
 
 /* PUBLIC INTERFACE */
 
-static void on_header_not_set(void *user_data, grpc_mdelem *md) {
-  GPR_UNREACHABLE_CODE(return );
-}
-
 void grpc_chttp2_hpack_parser_init(grpc_chttp2_hpack_parser *p) {
-  p->on_header = on_header_not_set;
+  p->on_header = NULL;
   p->on_header_user_data = NULL;
   p->state = parse_begin;
   p->key.str = NULL;
@@ -1455,7 +1455,7 @@ grpc_chttp2_parse_error grpc_chttp2_header_parser_parse(
         stream_parsing->received_close = 1;
       }
     }
-    parser->on_header = on_header_not_set;
+    parser->on_header = NULL;
     parser->on_header_user_data = NULL;
     parser->is_boundary = 0xde;
     parser->is_eof = 0xde;