1 files changed, 35 insertions, 12 deletions
diff --git a/net/socket/tcp_socket.cc b/net/socket/tcp_socket.cc
index f7eced9..6370362 100644
--- a/net/socket/tcp_socket.cc
+++ b/net/socket/tcp_socket.cc
@@ -6,50 +6,73 @@
 
 #include "base/file_util.h"
 #include "base/files/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "base/threading/worker_pool.h"
 
 namespace net {
 
 namespace {
 
+bool g_tcp_fastopen_enabled = false;
+
 #if defined(OS_LINUX) || defined(OS_ANDROID)
 
+typedef base::RefCountedData<bool> SharedBoolean;
+
 // Checks to see if the system supports TCP FastOpen. Notably, it requires
 // kernel support. Additionally, this checks system configuration to ensure that
 // it's enabled.
-bool SystemSupportsTCPFastOpen() {
+void SystemSupportsTCPFastOpen(scoped_refptr<SharedBoolean> supported) {
+  supported->data = false;
   static const base::FilePath::CharType kTCPFastOpenProcFilePath[] =
       "/proc/sys/net/ipv4/tcp_fastopen";
   std::string system_enabled_tcp_fastopen;
-  if (!base::ReadFileToString(
-          base::FilePath(kTCPFastOpenProcFilePath),
-          &system_enabled_tcp_fastopen)) {
-    return false;
+  if (!base::ReadFileToString(base::FilePath(kTCPFastOpenProcFilePath),
+                              &system_enabled_tcp_fastopen)) {
+    return;
   }
 
   // As per http://lxr.linux.no/linux+v3.7.7/include/net/tcp.h#L225
   // TFO_CLIENT_ENABLE is the LSB
   if (system_enabled_tcp_fastopen.empty() ||
       (system_enabled_tcp_fastopen[0] & 0x1) == 0) {
-    return false;
+    return;
   }
 
-  return true;
+  supported->data = true;
+}
+
+void EnableCallback(scoped_refptr<SharedBoolean> supported) {
+  g_tcp_fastopen_enabled = supported->data;
+}
+
+// This is asynchronous because it needs to do file IO, and it isn't allowed to
+// do that on the IO thread.
+void EnableFastOpenIfSupported() {
+  scoped_refptr<SharedBoolean> supported = new SharedBoolean;
+  base::WorkerPool::PostTaskAndReply(
+      FROM_HERE,
+      base::Bind(SystemSupportsTCPFastOpen, supported),
+      base::Bind(EnableCallback, supported),
+      false);
 }
 
 #else
 
-bool SystemSupportsTCPFastOpen() {
-  return false;
+void EnableFastOpenIfSupported() {
+  g_tcp_fastopen_enabled = false;
 }
 
 #endif
 
-bool g_tcp_fastopen_enabled = false;
-
 }  // namespace
 
 void SetTCPFastOpenEnabled(bool value) {
-  g_tcp_fastopen_enabled = value && SystemSupportsTCPFastOpen();
+  if (value) {
+    EnableFastOpenIfSupported();
+  } else {
+    g_tcp_fastopen_enabled = false;
+  }
 }
 
 bool IsTCPFastOpenEnabled() {