Merge 84251, 85083, 85188, 85375, 77501.

src/net/socket/tcp_client_socket_pool.cc

Index: src/net/socket/tcp_client_socket_pool.cc
===================================================================
--- src/net/socket/tcp_client_socket_pool.cc	(revision 85857)
+++ src/net/socket/tcp_client_socket_pool.cc	(working copy)
@@ -10,8 +10,10 @@
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/time.h"
+#include "net/base/ip_endpoint.h"
 #include "net/base/net_log.h"
 #include "net/base/net_errors.h"
+#include "net/base/sys_addrinfo.h"
 #include "net/socket/client_socket_factory.h"
 #include "net/socket/client_socket_handle.h"
 #include "net/socket/client_socket_pool_base.h"
@@ -21,9 +23,45 @@
 
 namespace net {
 
-TCPSocketParams::TCPSocketParams(const HostPortPair& host_port_pair,
-                                 RequestPriority priority, const GURL& referrer,
-                                 bool disable_resolver_cache)
+// TODO(willchan): Base this off RTT instead of statically setting it. Note we
+// choose a timeout that is different from the backup connect job timer so they
+// don't synchronize.
+const int TCPConnectJob::kIPv6FallbackTimerInMs = 300;
+
+namespace {
+
+bool AddressListStartsWithIPv6AndHasAnIPv4Addr(const AddressList& addrlist) {
+  const struct addrinfo* ai = addrlist.head();
+  if (ai->ai_family != AF_INET6)
+    return false;
+
+  ai = ai->ai_next;
+  while (ai) {
+    if (ai->ai_family != AF_INET6)
+      return true;
+    ai = ai->ai_next;
+  }
+
+  return false;
+}
+
+bool AddressListOnlyContainsIPv6Addresses(const AddressList& addrlist) {
+  DCHECK(addrlist.head());
+  for (const struct addrinfo* ai = addrlist.head(); ai; ai = ai->ai_next) {
+    if (ai->ai_family != AF_INET6)
+      return false;
+  }
+
+  return true;
+}
+
+}  // namespace
+
+TCPSocketParams::TCPSocketParams(
+    const HostPortPair& host_port_pair,
+    RequestPriority priority,
+    const GURL& referrer,
+    bool disable_resolver_cache)
     : destination_(host_port_pair) {
   Initialize(priority, referrer, disable_resolver_cache);
 }
@@ -76,7 +114,11 @@
       ALLOW_THIS_IN_INITIALIZER_LIST(
           callback_(this,
                     &TCPConnectJob::OnIOComplete)),
-      resolver_(host_resolver) {}
+      resolver_(host_resolver),
+      ALLOW_THIS_IN_INITIALIZER_LIST(
+          fallback_callback_(
+              this,
+              &TCPConnectJob::DoIPv6FallbackTCPConnectComplete)) {}
 
 TCPConnectJob::~TCPConnectJob() {
   // We don't worry about cancelling the host resolution and TCP connect, since
@@ -97,6 +139,38 @@
   }
 }
 
+// static
+void TCPConnectJob::MakeAddrListStartWithIPv4(AddressList* addrlist) {
+  if (addrlist->head()->ai_family != AF_INET6)
+    return;
+  bool has_ipv4 = false;
+  for (const struct addrinfo* ai = addrlist->head(); ai; ai = ai->ai_next) {
+    if (ai->ai_family != AF_INET6) {
+      has_ipv4 = true;
+      break;
+    }
+  }
+  if (!has_ipv4)
+    return;
+
+  struct addrinfo* head = CreateCopyOfAddrinfo(addrlist->head(), true);
+  struct addrinfo* tail = head;
+  while (tail->ai_next)
+    tail = tail->ai_next;
+  char* canonname = head->ai_canonname;
+  head->ai_canonname = NULL;
+  while (head->ai_family == AF_INET6) {
+    tail->ai_next = head;
+    tail = head;
+    head = head->ai_next;
+    tail->ai_next = NULL;
+  }
+  head->ai_canonname = canonname;
+
+  addrlist->Copy(head, true);
+  FreeCopyOfAddrinfo(head);
+}
+
 void TCPConnectJob::OnIOComplete(int result) {
   int rv = DoLoop(result);
   if (rv != ERR_IO_PENDING)
@@ -149,14 +223,22 @@
 
 int TCPConnectJob::DoTCPConnect() {
   next_state_ = STATE_TCP_CONNECT_COMPLETE;
-  set_socket(client_socket_factory_->CreateTCPClientSocket(
+  transport_socket_.reset(client_socket_factory_->CreateTCPClientSocket(
         addresses_, net_log().net_log(), net_log().source()));
   connect_start_time_ = base::TimeTicks::Now();
-  return socket()->Connect(&callback_);
+  int rv = transport_socket_->Connect(&callback_);
+  if (rv == ERR_IO_PENDING &&
+      AddressListStartsWithIPv6AndHasAnIPv4Addr(addresses_)) {
+    fallback_timer_.Start(
+        base::TimeDelta::FromMilliseconds(kIPv6FallbackTimerInMs),
+        this, &TCPConnectJob::DoIPv6FallbackTCPConnect);
+  }
+  return rv;
 }
 
 int TCPConnectJob::DoTCPConnectComplete(int result) {
   if (result == OK) {
+    bool is_ipv4 = addresses_.head()->ai_family != AF_INET6;
     DCHECK(connect_start_time_ != base::TimeTicks());
     DCHECK(start_time_ != base::TimeTicks());
     base::TimeTicks now = base::TimeTicks::Now();
@@ -174,14 +256,107 @@
         base::TimeDelta::FromMilliseconds(1),
         base::TimeDelta::FromMinutes(10),
         100);
+
+    if (is_ipv4) {
+      UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv4_No_Race",
+                                 connect_duration,
+                                 base::TimeDelta::FromMilliseconds(1),
+                                 base::TimeDelta::FromMinutes(10),
+                                 100);
+    } else {
+      if (AddressListOnlyContainsIPv6Addresses(addresses_)) {
+        UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv6_Solo",
+                                   connect_duration,
+                                   base::TimeDelta::FromMilliseconds(1),
+                                   base::TimeDelta::FromMinutes(10),
+                                   100);
+      } else {
+        UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv6_Raceable",
+                                   connect_duration,
+                                   base::TimeDelta::FromMilliseconds(1),
+                                   base::TimeDelta::FromMinutes(10),
+                                   100);
+      }
+    }
+    set_socket(transport_socket_.release());
+    fallback_timer_.Stop();
   } else {
-    // Delete the socket on error.
-    set_socket(NULL);
+    // Be a bit paranoid and kill off the fallback members to prevent reuse.
+    fallback_transport_socket_.reset();
+    fallback_addresses_.reset();
   }
 
   return result;
 }
 
+void TCPConnectJob::DoIPv6FallbackTCPConnect() {
+  // The timer should only fire while we're waiting for the main connect to
+  // succeed.
+  if (next_state_ != STATE_TCP_CONNECT_COMPLETE) {
+    NOTREACHED();
+    return;
+  }
+
+  DCHECK(!fallback_transport_socket_.get());
+  DCHECK(!fallback_addresses_.get());
+
+  fallback_addresses_.reset(new AddressList(addresses_));
+  MakeAddrListStartWithIPv4(fallback_addresses_.get());
+  fallback_transport_socket_.reset(
+      client_socket_factory_->CreateTCPClientSocket(
+          *fallback_addresses_, net_log().net_log(), net_log().source()));
+  fallback_connect_start_time_ = base::TimeTicks::Now();
+  int rv = fallback_transport_socket_->Connect(&fallback_callback_);
+  if (rv != ERR_IO_PENDING)
+    DoIPv6FallbackTCPConnectComplete(rv);
+}
+
+void TCPConnectJob::DoIPv6FallbackTCPConnectComplete(int result) {
+  // This should only happen when we're waiting for the main connect to succeed.
+  if (next_state_ != STATE_TCP_CONNECT_COMPLETE) {
+    NOTREACHED();
+    return;
+  }
+
+  DCHECK_NE(ERR_IO_PENDING, result);
+  DCHECK(fallback_transport_socket_.get());
+  DCHECK(fallback_addresses_.get());
+
+  if (result == OK) {
+    DCHECK(fallback_connect_start_time_ != base::TimeTicks());
+    DCHECK(start_time_ != base::TimeTicks());
+    base::TimeTicks now = base::TimeTicks::Now();
+    base::TimeDelta total_duration = now - start_time_;
+    UMA_HISTOGRAM_CUSTOM_TIMES(
+        "Net.DNS_Resolution_And_TCP_Connection_Latency2",
+        total_duration,
+        base::TimeDelta::FromMilliseconds(1),
+        base::TimeDelta::FromMinutes(10),
+        100);
+
+    base::TimeDelta connect_duration = now - fallback_connect_start_time_;
+    UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency",
+        connect_duration,
+        base::TimeDelta::FromMilliseconds(1),
+        base::TimeDelta::FromMinutes(10),
+        100);
+
+    UMA_HISTOGRAM_CUSTOM_TIMES("Net.TCP_Connection_Latency_IPv4_Wins_Race",
+        connect_duration,
+        base::TimeDelta::FromMilliseconds(1),
+        base::TimeDelta::FromMinutes(10),
+        100);
+    set_socket(fallback_transport_socket_.release());
+    next_state_ = STATE_NONE;
+    transport_socket_.reset();
+  } else {
+    // Be a bit paranoid and kill off the fallback members to prevent reuse.
+    fallback_transport_socket_.reset();
+    fallback_addresses_.reset();
+  }
+  NotifyDelegateOfCompletion(result);  // Deletes |this|
+}
+
 int TCPConnectJob::ConnectInternal() {
   next_state_ = STATE_RESOLVE_HOST;
   start_time_ = base::TimeTicks::Now();