From 6d594cc227f153364b91e8310d59a07d7d6ce5f6 Mon Sep 17 00:00:00 2001
From: Tao Wang <t55wang@uwaterloo.ca>
Date: Tue, 2 Apr 2013 15:56:49 -0700
Subject: [PATCH] Bug 3875: Use Optimistic Data SOCKS variant.

This patch alters Firefox's SOCKS handshake to preemptively send data before
it is actually connected. This allows us to save a round trip during
connection setup.

See:
https://gitweb.torproject.org/torspec.git/blob/HEAD:/proposals/181-optimistic-data-client.txt
---
 netwerk/base/nsSocketTransport2.cpp | 44 +++++++++++++++++++++++------
 netwerk/base/nsSocketTransport2.h   |  4 ++-
 netwerk/socket/nsSOCKSIOLayer.cpp   |  3 +-
 3 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/netwerk/base/nsSocketTransport2.cpp b/netwerk/base/nsSocketTransport2.cpp
index 1bfd1fc915255..4399465fe5347 100644
--- a/netwerk/base/nsSocketTransport2.cpp
+++ b/netwerk/base/nsSocketTransport2.cpp
@@ -1983,7 +1983,26 @@ nsSocketTransport::OnSocketReady(PRFileDesc *fd, int16_t outFlags)
         // Update poll timeout in case it was changed
         mPollTimeout = mTimeouts[TIMEOUT_READ_WRITE];
     }
-    else if ((mState == STATE_CONNECTING) && !gIOService->IsNetTearingDown()) {
+    // Tor 3875: Use optimistic data with SOCKS.
+    // To accomplish this, two new states were added that are only used with
+    // SOCKS connections:
+    //   STATE_SENDINGGET - The SOCKS handshake has proceeded to the
+    //                        "sent connect" state; now it is okay to
+    //                         optimistically send some application data (e.g.,
+    //                         an HTTP GET request).
+    //   STATE_SENTGET -    Optimistic data has been sent; make a second call
+    //                        to PR_ConnectContinue() to allow the SOCKS
+    //                        handshake to finish.
+    else if (mState == STATE_SENDINGGET) {
+        if ((mPollFlags & PR_POLL_WRITE) && (outFlags & ~PR_POLL_READ)) {
+            mOutput.OnSocketReady(NS_OK);  // Allow application data to be sent.
+        }
+        mPollTimeout = mTimeouts[TIMEOUT_READ_WRITE];
+        mPollFlags = (PR_POLL_EXCEPT | PR_POLL_READ);
+        mState = STATE_SENTGET;  // Wait for SOCKS handshake response.
+    }
+    else if (((mState == STATE_CONNECTING) || (mState = STATE_SENTGET)) &&
+             !gIOService->IsNetTearingDown()) {
         // We do not need to do PR_ConnectContinue when we are already
         // shutting down.
 
@@ -2007,7 +2026,14 @@ nsSocketTransport::OnSocketReady(PRFileDesc *fd, int16_t outFlags)
                 Telemetry::PRCONNECTCONTINUE_BLOCKING_TIME_OFFLINE);
         }
 
-        if (status == PR_SUCCESS) {
+        bool isUsingSocks = mProxyTransparent && !mProxyHost.IsEmpty();
+        if (status == PR_SUCCESS && mState == STATE_CONNECTING) {
+            OnSocketConnected();
+            if (isUsingSocks) {
+                mState = STATE_SENDINGGET;
+            }
+        }
+        else if (status == PR_SUCCESS && mState == STATE_SENTGET) {
             //
             // we are connected!
             //
@@ -2034,17 +2060,17 @@ nsSocketTransport::OnSocketReady(PRFileDesc *fd, int16_t outFlags)
             // If the connect is still not ready, then continue polling...
             //
             if ((PR_WOULD_BLOCK_ERROR == code) || (PR_IN_PROGRESS_ERROR == code)) {
-                // Set up the select flags for connect...
-                mPollFlags = (PR_POLL_EXCEPT | PR_POLL_WRITE);
-                // Update poll timeout in case it was changed
-                mPollTimeout = mTimeouts[TIMEOUT_CONNECT];
+                if (mState != STATE_SENTGET) {
+                    // Set up the select flags for connect...
+                    mPollFlags = (PR_POLL_EXCEPT | PR_POLL_WRITE);
+                    // Update poll timeout in case it was changed
+                    mPollTimeout = mTimeouts[TIMEOUT_CONNECT];
+                }
             }
             //
             // The SOCKS proxy rejected our request. Find out why.
             //
-            else if (PR_UNKNOWN_ERROR == code &&
-                     mProxyTransparent &&
-                     !mProxyHost.IsEmpty()) {
+            else if (PR_UNKNOWN_ERROR == code && isUsingSocks) {
                 code = PR_GetOSError();
                 mCondition = ErrorAccordingToNSPR(code);
             }
diff --git a/netwerk/base/nsSocketTransport2.h b/netwerk/base/nsSocketTransport2.h
index 7c85ccdc409f2..b4baed233ff1b 100644
--- a/netwerk/base/nsSocketTransport2.h
+++ b/netwerk/base/nsSocketTransport2.h
@@ -201,7 +201,9 @@ private:
         STATE_IDLE,
         STATE_RESOLVING,
         STATE_CONNECTING,
-        STATE_TRANSFERRING
+        STATE_TRANSFERRING,
+        STATE_SENDINGGET,
+        STATE_SENTGET
     };
 
     // Safer way to get and automatically release PRFileDesc objects.
diff --git a/netwerk/socket/nsSOCKSIOLayer.cpp b/netwerk/socket/nsSOCKSIOLayer.cpp
index 22f5751fbe963..41699e47ef77b 100644
--- a/netwerk/socket/nsSOCKSIOLayer.cpp
+++ b/netwerk/socket/nsSOCKSIOLayer.cpp
@@ -83,7 +83,8 @@ public:
     void SetConnectTimeout(PRIntervalTime to);
     PRStatus DoHandshake(PRFileDesc *fd, int16_t oflags = -1);
     int16_t GetPollFlags() const;
-    bool IsConnected() const { return mState == SOCKS_CONNECTED; }
+    bool IsConnected() const { return (mState == SOCKS_CONNECTED ||
+                                       mState == SOCKS5_READ_CONNECT_RESPONSE_TOP); }
     void ForgetFD() { mFD = nullptr; }
     void SetNamedPipeFD(PRFileDesc *fd) { mFD = fd; }
 
-- 
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