Merge github.com:grpc/grpc into backoff_lib

16 files changed, 182 insertions, 73 deletions

diff --git a/src/core/client_config/client_config.c b/src/core/client_config/client_config.c
index 6ecffb3854..c500af25ee 100644
--- a/src/core/client_config/client_config.c
+++ b/src/core/client_config/client_config.c
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,7 +53,9 @@ void grpc_client_config_ref(grpc_client_config *c) { gpr_ref(&c->refs); }
 
 void grpc_client_config_unref(grpc_exec_ctx *exec_ctx, grpc_client_config *c) {
   if (gpr_unref(&c->refs)) {
-    GRPC_LB_POLICY_UNREF(exec_ctx, c->lb_policy, "client_config");
+    if (c->lb_policy != NULL) {
+      GRPC_LB_POLICY_UNREF(exec_ctx, c->lb_policy, "client_config");
+    }
     gpr_free(c);
   }
 }
diff --git a/src/core/client_config/lb_policies/pick_first.c b/src/core/client_config/lb_policies/pick_first.c
index 81167b31c8..8ed1223d39 100644
--- a/src/core/client_config/lb_policies/pick_first.c
+++ b/src/core/client_config/lb_policies/pick_first.c
@@ -387,8 +387,8 @@ static void pick_first_factory_unref(grpc_lb_policy_factory *factory) {}
 
 static grpc_lb_policy *create_pick_first(grpc_lb_policy_factory *factory,
                                          grpc_lb_policy_args *args) {
+  if (args->num_subchannels == 0) return NULL;
   pick_first_lb_policy *p = gpr_malloc(sizeof(*p));
-  GPR_ASSERT(args->num_subchannels > 0);
   memset(p, 0, sizeof(*p));
   grpc_lb_policy_init(&p->base, &pick_first_lb_policy_vtable);
   p->subchannels =
diff --git a/src/core/client_config/resolvers/dns_resolver.c b/src/core/client_config/resolvers/dns_resolver.c
index 376b6b3d76..e28e4757a1 100644
--- a/src/core/client_config/resolvers/dns_resolver.c
+++ b/src/core/client_config/resolvers/dns_resolver.c
@@ -41,6 +41,7 @@
 
 #include "src/core/client_config/lb_policy_registry.h"
 #include "src/core/iomgr/resolve_address.h"
+#include "src/core/iomgr/timer.h"
 #include "src/core/support/string.h"
 
 typedef struct {
@@ -71,6 +72,9 @@ typedef struct {
   grpc_client_config **target_config;
   /** current (fully resolved) config */
   grpc_client_config *resolved_config;
+  /** retry timer */
+  bool have_retry_timer;
+  grpc_timer retry_timer;
 } dns_resolver;
 
 static void dns_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *r);
@@ -91,6 +95,9 @@ static const grpc_resolver_vtable dns_resolver_vtable = {
 static void dns_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver) {
   dns_resolver *r = (dns_resolver *)resolver;
   gpr_mu_lock(&r->mu);
+  if (r->have_retry_timer) {
+    grpc_timer_cancel(exec_ctx, &r->retry_timer);
+  }
   if (r->next_completion != NULL) {
     *r->target_config = NULL;
     grpc_exec_ctx_enqueue(exec_ctx, r->next_completion, true, NULL);
@@ -125,6 +132,22 @@ static void dns_next(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
   gpr_mu_unlock(&r->mu);
 }
 
+static void dns_on_retry_timer(grpc_exec_ctx *exec_ctx, void *arg,
+                               bool success) {
+  dns_resolver *r = arg;
+
+  gpr_mu_lock(&r->mu);
+  r->have_retry_timer = false;
+  if (success) {
+    if (!r->resolving) {
+      dns_start_resolving_locked(r);
+    }
+  }
+  gpr_mu_unlock(&r->mu);
+
+  GRPC_RESOLVER_UNREF(exec_ctx, &r->base, "retry-timer");
+}
+
 static void dns_on_resolved(grpc_exec_ctx *exec_ctx, void *arg,
                             grpc_resolved_addresses *addresses) {
   dns_resolver *r = arg;
@@ -133,29 +156,47 @@ static void dns_on_resolved(grpc_exec_ctx *exec_ctx, void *arg,
   grpc_subchannel_args args;
   grpc_lb_policy *lb_policy;
   size_t i;
-  if (addresses) {
+  gpr_mu_lock(&r->mu);
+  GPR_ASSERT(r->resolving);
+  r->resolving = 0;
+  if (addresses != NULL) {
     grpc_lb_policy_args lb_policy_args;
     config = grpc_client_config_create();
     subchannels = gpr_malloc(sizeof(grpc_subchannel *) * addresses->naddrs);
+    size_t naddrs = 0;
     for (i = 0; i < addresses->naddrs; i++) {
       memset(&args, 0, sizeof(args));
       args.addr = (struct sockaddr *)(addresses->addrs[i].addr);
       args.addr_len = (size_t)addresses->addrs[i].len;
-      subchannels[i] = grpc_subchannel_factory_create_subchannel(
+      grpc_subchannel *subchannel = grpc_subchannel_factory_create_subchannel(
           exec_ctx, r->subchannel_factory, &args);
+      if (subchannel != NULL) {
+        subchannels[naddrs++] = subchannel;
+      }
     }
     memset(&lb_policy_args, 0, sizeof(lb_policy_args));
     lb_policy_args.subchannels = subchannels;
-    lb_policy_args.num_subchannels = addresses->naddrs;
+    lb_policy_args.num_subchannels = naddrs;
     lb_policy = grpc_lb_policy_create(r->lb_policy_name, &lb_policy_args);
-    grpc_client_config_set_lb_policy(config, lb_policy);
-    GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "construction");
+    if (lb_policy != NULL) {
+      grpc_client_config_set_lb_policy(config, lb_policy);
+      GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "construction");
+    }
     grpc_resolved_addresses_destroy(addresses);
     gpr_free(subchannels);
+  } else {
+    int retry_seconds = 15;
+    gpr_log(GPR_DEBUG, "dns resolution failed: retrying in %d seconds",
+            retry_seconds);
+    GPR_ASSERT(!r->have_retry_timer);
+    r->have_retry_timer = true;
+    gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+    GRPC_RESOLVER_REF(&r->base, "retry-timer");
+    grpc_timer_init(
+        exec_ctx, &r->retry_timer,
+        gpr_time_add(now, gpr_time_from_seconds(retry_seconds, GPR_TIMESPAN)),
+        dns_on_retry_timer, r, now);
   }
-  gpr_mu_lock(&r->mu);
-  GPR_ASSERT(r->resolving);
-  r->resolving = 0;
   if (r->resolved_config) {
     grpc_client_config_unref(exec_ctx, r->resolved_config);
   }
diff --git a/src/core/client_config/subchannel.c b/src/core/client_config/subchannel.c
index 0801c20fce..5dea215668 100644
--- a/src/core/client_config/subchannel.c
+++ b/src/core/client_config/subchannel.c
@@ -519,7 +519,8 @@ void grpc_connected_subchannel_ping(grpc_exec_ctx *exec_ctx,
   elem->filter->start_transport_op(exec_ctx, elem, &op);
 }
 
-static void publish_transport(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
+static void publish_transport_locked(grpc_exec_ctx *exec_ctx,
+                                     grpc_subchannel *c) {
   size_t channel_stack_size;
   grpc_connected_subchannel *con;
   grpc_channel_stack *stk;
@@ -555,8 +556,6 @@ static void publish_transport(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
   grpc_closure_init(&sw_subchannel->closure, subchannel_on_child_state_changed,
                     sw_subchannel);
 
-  gpr_mu_lock(&c->mu);
-
   if (c->disconnected) {
     gpr_mu_unlock(&c->mu);
     gpr_free(sw_subchannel);
@@ -589,7 +588,6 @@ static void publish_transport(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
   grpc_connectivity_state_set(exec_ctx, &c->state_tracker, GRPC_CHANNEL_READY,
                               "connected");
 
-  gpr_mu_unlock(&c->mu);
   gpr_free((void *)filters);
 }
 
@@ -615,21 +613,23 @@ static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *arg,
                                  bool iomgr_success) {
   grpc_subchannel *c = arg;
 
+  GRPC_SUBCHANNEL_WEAK_REF(c, "connected");
+  gpr_mu_lock(&c->mu);
   if (c->connecting_result.transport != NULL) {
-    publish_transport(exec_ctx, c);
+    publish_transport_locked(exec_ctx, c);
   } else if (c->disconnected) {
     GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
   } else {
     gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
-    gpr_mu_lock(&c->mu);
     GPR_ASSERT(!c->have_alarm);
     c->have_alarm = 1;
     grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
                                 GRPC_CHANNEL_TRANSIENT_FAILURE,
                                 "connect_failed");
     grpc_timer_init(exec_ctx, &c->alarm, c->next_attempt, on_alarm, c, now);
-    gpr_mu_unlock(&c->mu);
   }
+  gpr_mu_unlock(&c->mu);
+  GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
 }
 
 /*
diff --git a/src/core/iomgr/iocp_windows.c b/src/core/iomgr/iocp_windows.c
index 807729708e..fa87e5246b 100644
--- a/src/core/iomgr/iocp_windows.c
+++ b/src/core/iomgr/iocp_windows.c
@@ -71,7 +71,8 @@ static DWORD deadline_to_millis_timeout(gpr_timespec deadline,
       timeout, gpr_time_from_nanos(GPR_NS_PER_MS - 1, GPR_TIMESPAN)));
 }
 
-void grpc_iocp_work(grpc_exec_ctx *exec_ctx, gpr_timespec deadline) {
+grpc_iocp_work_status grpc_iocp_work(grpc_exec_ctx *exec_ctx,
+                                     gpr_timespec deadline) {
   BOOL success;
   DWORD bytes = 0;
   DWORD flags = 0;
@@ -84,14 +85,14 @@ void grpc_iocp_work(grpc_exec_ctx *exec_ctx, gpr_timespec deadline) {
       g_iocp, &bytes, &completion_key, &overlapped,
       deadline_to_millis_timeout(deadline, gpr_now(deadline.clock_type)));
   if (success == 0 && overlapped == NULL) {
-    return;
+    return GRPC_IOCP_WORK_TIMEOUT;
   }
   GPR_ASSERT(completion_key && overlapped);
   if (overlapped == &g_iocp_custom_overlap) {
     gpr_atm_full_fetch_add(&g_custom_events, -1);
     if (completion_key == (ULONG_PTR)&g_iocp_kick_token) {
       /* We were awoken from a kick. */
-      return;
+      return GRPC_IOCP_WORK_KICK;
     }
     gpr_log(GPR_ERROR, "Unknown custom completion key.");
     abort();
@@ -121,6 +122,7 @@ void grpc_iocp_work(grpc_exec_ctx *exec_ctx, gpr_timespec deadline) {
   }
   gpr_mu_unlock(&socket->state_mu);
   grpc_exec_ctx_enqueue(exec_ctx, closure, true, NULL);
+  return GRPC_IOCP_WORK_WORK;
 }
 
 void grpc_iocp_init(void) {
@@ -140,10 +142,12 @@ void grpc_iocp_kick(void) {
 
 void grpc_iocp_flush(void) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_iocp_work_status work_status;
 
   do {
-    grpc_iocp_work(&exec_ctx, gpr_inf_past(GPR_CLOCK_MONOTONIC));
-  } while (grpc_exec_ctx_flush(&exec_ctx));
+    work_status = grpc_iocp_work(&exec_ctx, gpr_inf_past(GPR_CLOCK_MONOTONIC));
+  } while (work_status == GRPC_IOCP_WORK_KICK ||
+           grpc_exec_ctx_flush(&exec_ctx));
 }
 
 void grpc_iocp_shutdown(void) {
diff --git a/src/core/iomgr/iocp_windows.h b/src/core/iomgr/iocp_windows.h
index 75f3ba8477..8b2b1aeb5c 100644
--- a/src/core/iomgr/iocp_windows.h
+++ b/src/core/iomgr/iocp_windows.h
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -38,7 +38,14 @@
 
 #include "src/core/iomgr/socket_windows.h"
 
-void grpc_iocp_work(grpc_exec_ctx *exec_ctx, gpr_timespec deadline);
+typedef enum {
+  GRPC_IOCP_WORK_WORK,
+  GRPC_IOCP_WORK_TIMEOUT,
+  GRPC_IOCP_WORK_KICK
+} grpc_iocp_work_status;
+
+grpc_iocp_work_status grpc_iocp_work(grpc_exec_ctx *exec_ctx,
+                                     gpr_timespec deadline);
 void grpc_iocp_init(void);
 void grpc_iocp_kick(void);
 void grpc_iocp_flush(void);
diff --git a/src/core/iomgr/resolve_address.h b/src/core/iomgr/resolve_address.h
index 01eedffa88..b059630457 100644
--- a/src/core/iomgr/resolve_address.h
+++ b/src/core/iomgr/resolve_address.h
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -66,7 +66,7 @@ void grpc_resolved_addresses_destroy(grpc_resolved_addresses *addresses);
 
 /* Resolve addr in a blocking fashion. Returns NULL on failure. On success,
    result must be freed with grpc_resolved_addresses_destroy. */
-grpc_resolved_addresses *grpc_blocking_resolve_address(
-    const char *addr, const char *default_port);
+extern grpc_resolved_addresses *(*grpc_blocking_resolve_address)(
+    const char *name, const char *default_port);
 
 #endif /* GRPC_INTERNAL_CORE_IOMGR_RESOLVE_ADDRESS_H */
diff --git a/src/core/iomgr/resolve_address_posix.c b/src/core/iomgr/resolve_address_posix.c
index c51745b918..a6c9893f23 100644
--- a/src/core/iomgr/resolve_address_posix.c
+++ b/src/core/iomgr/resolve_address_posix.c
@@ -34,18 +34,13 @@
 #include <grpc/support/port_platform.h>
 #ifdef GPR_POSIX_SOCKET
 
-#include "src/core/iomgr/sockaddr.h"
 #include "src/core/iomgr/resolve_address.h"
+#include "src/core/iomgr/sockaddr.h"
 
+#include <string.h>
 #include <sys/types.h>
 #include <sys/un.h>
-#include <string.h>
 
-#include "src/core/iomgr/executor.h"
-#include "src/core/iomgr/iomgr_internal.h"
-#include "src/core/iomgr/sockaddr_utils.h"
-#include "src/core/support/block_annotate.h"
-#include "src/core/support/string.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/host_port.h>
 #include <grpc/support/log.h>
@@ -53,6 +48,11 @@
 #include <grpc/support/thd.h>
 #include <grpc/support/time.h>
 #include <grpc/support/useful.h>
+#include "src/core/iomgr/executor.h"
+#include "src/core/iomgr/iomgr_internal.h"
+#include "src/core/iomgr/sockaddr_utils.h"
+#include "src/core/support/block_annotate.h"
+#include "src/core/support/string.h"
 
 typedef struct {
   char *name;
@@ -62,7 +62,7 @@ typedef struct {
   void *arg;
 } request;
 
-grpc_resolved_addresses *grpc_blocking_resolve_address(
+static grpc_resolved_addresses *blocking_resolve_address_impl(
     const char *name, const char *default_port) {
   struct addrinfo hints;
   struct addrinfo *result = NULL, *resp;
@@ -150,6 +150,9 @@ done:
   return addrs;
 }
 
+grpc_resolved_addresses *(*grpc_blocking_resolve_address)(
+    const char *name, const char *default_port) = blocking_resolve_address_impl;
+
 /* Callback to be passed to grpc_executor to asynch-ify
  * grpc_blocking_resolve_address */
 static void do_request_thread(grpc_exec_ctx *exec_ctx, void *rp, bool success) {
diff --git a/src/core/iomgr/resolve_address_windows.c b/src/core/iomgr/resolve_address_windows.c
index 28c8661e73..472e797163 100644
--- a/src/core/iomgr/resolve_address_windows.c
+++ b/src/core/iomgr/resolve_address_windows.c
@@ -34,17 +34,12 @@
 #include <grpc/support/port_platform.h>
 #ifdef GPR_WINSOCK_SOCKET
 
-#include "src/core/iomgr/sockaddr.h"
 #include "src/core/iomgr/resolve_address.h"
+#include "src/core/iomgr/sockaddr.h"
 
-#include <sys/types.h>
 #include <string.h>
+#include <sys/types.h>
 
-#include "src/core/iomgr/executor.h"
-#include "src/core/iomgr/iomgr_internal.h"
-#include "src/core/iomgr/sockaddr_utils.h"
-#include "src/core/support/block_annotate.h"
-#include "src/core/support/string.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/host_port.h>
 #include <grpc/support/log.h>
@@ -52,6 +47,11 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/thd.h>
 #include <grpc/support/time.h>
+#include "src/core/iomgr/executor.h"
+#include "src/core/iomgr/iomgr_internal.h"
+#include "src/core/iomgr/sockaddr_utils.h"
+#include "src/core/support/block_annotate.h"
+#include "src/core/support/string.h"
 
 typedef struct {
   char *name;
@@ -61,7 +61,7 @@ typedef struct {
   void *arg;
 } request;
 
-grpc_resolved_addresses *grpc_blocking_resolve_address(
+static grpc_resolved_addresses *blocking_resolve_address_impl(
     const char *name, const char *default_port) {
   struct addrinfo hints;
   struct addrinfo *result = NULL, *resp;
@@ -133,6 +133,9 @@ done:
   return addrs;
 }
 
+grpc_resolved_addresses *(*grpc_blocking_resolve_address)(
+    const char *name, const char *default_port) = blocking_resolve_address_impl;
+
 /* Callback to be passed to grpc_executor to asynch-ify
  * grpc_blocking_resolve_address */
 static void do_request_thread(grpc_exec_ctx *exec_ctx, void *rp, bool success) {
diff --git a/src/core/iomgr/tcp_server_windows.c b/src/core/iomgr/tcp_server_windows.c
index ce930b8f41..a4abc5b974 100644
--- a/src/core/iomgr/tcp_server_windows.c
+++ b/src/core/iomgr/tcp_server_windows.c
@@ -240,8 +240,7 @@ static void decrement_active_ports_and_notify(grpc_exec_ctx *exec_ctx,
   sp->shutting_down = 0;
   gpr_mu_lock(&sp->server->mu);
   GPR_ASSERT(sp->server->active_ports > 0);
-  if (0 == --sp->server->active_ports &&
-      sp->server->shutdown_complete != NULL) {
+  if (0 == --sp->server->active_ports) {
     notify = 1;
   }
   gpr_mu_unlock(&sp->server->mu);
diff --git a/src/core/iomgr/timer.c b/src/core/iomgr/timer.c
index 8379fffad0..f444643428 100644
--- a/src/core/iomgr/timer.c
+++ b/src/core/iomgr/timer.c
@@ -33,11 +33,11 @@
 
 #include "src/core/iomgr/timer.h"
 
-#include "src/core/iomgr/timer_heap.h"
-#include "src/core/iomgr/time_averaged_stats.h"
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 #include <grpc/support/useful.h>
+#include "src/core/iomgr/time_averaged_stats.h"
+#include "src/core/iomgr/timer_heap.h"
 
 #define INVALID_HEAP_INDEX 0xffffffffu
 
@@ -330,6 +330,18 @@ static int run_some_expired_timers(grpc_exec_ctx *exec_ctx, gpr_timespec now,
 
     gpr_mu_unlock(&g_mu);
     gpr_mu_unlock(&g_checker_mu);
+  } else if (next != NULL) {
+    /* TODO(ctiller): this forces calling code to do an short poll, and
+       then retry the timer check (because this time through the timer list was
+       contended).
+
+       We could reduce the cost here dramatically by keeping a count of how many
+       currently active pollers got through the uncontended case above
+       successfully, and waking up other pollers IFF that count drops to zero.
+
+       Once that count is in place, this entire else branch could disappear. */
+    *next = gpr_time_min(
+        *next, gpr_time_add(now, gpr_time_from_millis(1, GPR_TIMESPAN)));
   }
 
   return (int)n;
diff --git a/src/core/iomgr/timer.h b/src/core/iomgr/timer.h
index 9ad1e92f42..e239e884e7 100644
--- a/src/core/iomgr/timer.h
+++ b/src/core/iomgr/timer.h
@@ -96,7 +96,6 @@ void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer);
    *next is never guaranteed to be updated on any given execution; however,
    with high probability at least one thread in the system will see an update
    at any time slice. */
-
 bool grpc_timer_check(grpc_exec_ctx *exec_ctx, gpr_timespec now,
                       gpr_timespec *next);
 void grpc_timer_list_init(gpr_timespec now);
diff --git a/src/core/support/alloc.c b/src/core/support/alloc.c
index 0a064b2c18..b99584bd20 100644
--- a/src/core/support/alloc.c
+++ b/src/core/support/alloc.c
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -87,4 +87,4 @@ void *gpr_malloc_aligned(size_t size, size_t alignment_log) {
   return (void *)ret;
 }
 
-void gpr_free_aligned(void *ptr) { free(((void **)ptr)[-1]); }
+void gpr_free_aligned(void *ptr) { gpr_free(((void **)ptr)[-1]); }
diff --git a/src/core/surface/completion_queue.c b/src/core/surface/completion_queue.c
index f6a95ebbd3..b22818ea87 100644
--- a/src/core/surface/completion_queue.c
+++ b/src/core/surface/completion_queue.c
@@ -86,7 +86,7 @@ struct grpc_completion_queue {
 #define POLLSET_FROM_CQ(cq) ((grpc_pollset *)(cq + 1))
 
 static gpr_mu g_freelist_mu;
-grpc_completion_queue *g_freelist;
+static grpc_completion_queue *g_freelist;
 
 static void on_pollset_shutdown_done(grpc_exec_ctx *exec_ctx, void *cc,
                                      bool success);
diff --git a/src/core/tsi/ssl_transport_security.c b/src/core/tsi/ssl_transport_security.c
index 6adcaac9ed..fcbd910f07 100644
--- a/src/core/tsi/ssl_transport_security.c
+++ b/src/core/tsi/ssl_transport_security.c
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -33,9 +33,18 @@
 
 #include "src/core/tsi/ssl_transport_security.h"
 
+#include <grpc/support/port_platform.h>
+
 #include <limits.h>
 #include <string.h>
 
+/* TODO(jboeuf): refactor inet_ntop into a portability header. */
+#ifdef GPR_WINSOCK_SOCKET
+#include <ws2tcpip.h>
+#else
+#include <arpa/inet.h>
+#endif
+
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 #include <grpc/support/thd.h>
@@ -197,13 +206,16 @@ static void ssl_info_callback(const SSL *ssl, int where, int ret) {
 }
 
 /* Returns 1 if name looks like an IP address, 0 otherwise.
-   This is a very rough heuristic as it does not handle IPV6 or things like:
-   0300.0250.00.01, 0xC0.0Xa8.0x0.0x1, 000030052000001, 0xc0.052000001 */
+   This is a very rough heuristic, and only handles IPv6 in hexadecimal form. */
 static int looks_like_ip_address(const char *name) {
   size_t i;
   size_t dot_count = 0;
   size_t num_size = 0;
   for (i = 0; i < strlen(name); i++) {
+    if (name[i] == ':') {
+      /* IPv6 Address in hexadecimal form, : is not allowed in DNS names. */
+      return 1;
+    }
     if (name[i] >= '0' && name[i] <= '9') {
       if (num_size > 3) return 0;
       num_size++;
@@ -296,21 +308,44 @@ static tsi_result add_subject_alt_names_properties_to_peer(
         sk_GENERAL_NAME_value(subject_alt_names, TSI_SIZE_AS_SIZE(i));
     /* Filter out the non-dns entries names. */
     if (subject_alt_name->type == GEN_DNS) {
-      unsigned char *dns_name = NULL;
-      int dns_name_size =
-          ASN1_STRING_to_UTF8(&dns_name, subject_alt_name->d.dNSName);
-      if (dns_name_size < 0) {
+      unsigned char *name = NULL;
+      int name_size;
+      name_size = ASN1_STRING_to_UTF8(&name, subject_alt_name->d.dNSName);
+      if (name_size < 0) {
         gpr_log(GPR_ERROR, "Could not get utf8 from asn1 string.");
         result = TSI_INTERNAL_ERROR;
         break;
       }
       result = tsi_construct_string_peer_property(
-          TSI_X509_SUBJECT_ALTERNATIVE_NAME_PEER_PROPERTY,
-          (const char *)dns_name, (size_t)dns_name_size,
+          TSI_X509_SUBJECT_ALTERNATIVE_NAME_PEER_PROPERTY, (const char *)name,
+          (size_t)name_size, &peer->properties[peer->property_count++]);
+      OPENSSL_free(name);
+    } else if (subject_alt_name->type == GEN_IPADD) {
+      char ntop_buf[INET6_ADDRSTRLEN];
+      int af;
+
+      if (subject_alt_name->d.iPAddress->length == 4) {
+        af = AF_INET;
+      } else if (subject_alt_name->d.iPAddress->length == 16) {
+        af = AF_INET6;
+      } else {
+        gpr_log(GPR_ERROR, "SAN IP Address contained invalid IP");
+        result = TSI_INTERNAL_ERROR;
+        break;
+      }
+      const char *name = inet_ntop(af, subject_alt_name->d.iPAddress->data,
+                                   ntop_buf, INET6_ADDRSTRLEN);
+      if (name == NULL) {
+        gpr_log(GPR_ERROR, "Could not get IP string from asn1 octet.");
+        result = TSI_INTERNAL_ERROR;
+        break;
+      }
+
+      result = tsi_construct_string_peer_property_from_cstring(
+          TSI_X509_SUBJECT_ALTERNATIVE_NAME_PEER_PROPERTY, name,
           &peer->properties[peer->property_count++]);
-      OPENSSL_free(dns_name);
-      if (result != TSI_OK) break;
     }
+    if (result != TSI_OK) break;
   }
   return result;
 }
@@ -1436,9 +1471,7 @@ int tsi_ssl_peer_matches_name(const tsi_peer *peer, const char *name) {
   size_t i = 0;
   size_t san_count = 0;
   const tsi_peer_property *cn_property = NULL;
-
-  /* For now reject what looks like an IP address. */
-  if (looks_like_ip_address(name)) return 0;
+  int like_ip = looks_like_ip_address(name);
 
   /* Check the SAN first. */
   for (i = 0; i < peer->property_count; i++) {
@@ -1447,8 +1480,15 @@ int tsi_ssl_peer_matches_name(const tsi_peer *peer, const char *name) {
     if (strcmp(property->name,
                TSI_X509_SUBJECT_ALTERNATIVE_NAME_PEER_PROPERTY) == 0) {
       san_count++;
-      if (does_entry_match_name(property->value.data, property->value.length,
-                                name)) {
+
+      if (!like_ip && does_entry_match_name(property->value.data,
+                                            property->value.length, name)) {
+        return 1;
+      } else if (like_ip &&
+                 strncmp(name, property->value.data, property->value.length) ==
+                     0 &&
+                 strlen(name) == property->value.length) {
+        /* IP Addresses are exact matches only. */
         return 1;
       }
     } else if (strcmp(property->name,
@@ -1457,8 +1497,8 @@ int tsi_ssl_peer_matches_name(const tsi_peer *peer, const char *name) {
     }
   }
 
-  /* If there's no SAN, try the CN. */
-  if (san_count == 0 && cn_property != NULL) {
+  /* If there's no SAN, try the CN, but only if its not like an IP Address */
+  if (san_count == 0 && cn_property != NULL && !like_ip) {
     if (does_entry_match_name(cn_property->value.data,
                               cn_property->value.length, name)) {
       return 1;
diff --git a/src/core/tsi/ssl_transport_security.h b/src/core/tsi/ssl_transport_security.h
index 51c0003a85..4909af4c47 100644
--- a/src/core/tsi/ssl_transport_security.h
+++ b/src/core/tsi/ssl_transport_security.h
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -162,8 +162,7 @@ void tsi_ssl_handshaker_factory_destroy(tsi_ssl_handshaker_factory *self);
    Still TODO(jboeuf):
    - handle mixed case.
    - handle %encoded chars.
-   - handle public suffix wildchar more strictly (e.g. *.co.uk)
-   - handle IP addresses in SAN. */
+   - handle public suffix wildchar more strictly (e.g. *.co.uk) */
 int tsi_ssl_peer_matches_name(const tsi_peer *peer, const char *name);
 
 #ifdef __cplusplus