net: When using False Start merge Finished and Application Data records.

When using False Start, this patch causes NSS to perform a single
write which contains the ClientKeyExchange, ChangeCipherSpec, Finished
and first application data record.

This removes a source of non-determinism when dealing with False Start
intolerant servers. Previously, Chrome may, or may not work depending
on network timing.

BUG=none
TEST=none

http://codereview.chromium.org/3331005/show

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@58838 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 26 insertions, 8 deletions

diff --git a/net/base/nss_memio.c b/net/base/nss_memio.c
index 5f7fd00..8b45c49 100644
--- a/net/base/nss_memio.c
+++ b/net/base/nss_memio.c
@@ -70,6 +70,9 @@ static void memio_buffer_destroy(struct memio_buffer *mb);
 /* How many bytes can be read out of the buffer without wrapping */
 static int memio_buffer_used_contiguous(const struct memio_buffer *mb);
 
+/* How many bytes exist after the wrap? */
+static int memio_buffer_wrapped_bytes(const struct memio_buffer *mb);
+
 /* How many bytes can be written into the buffer without wrapping */
 static int memio_buffer_unused_contiguous(const struct memio_buffer *mb);
 
@@ -103,6 +106,12 @@ static int memio_buffer_used_contiguous(const struct memio_buffer *mb)
     return (((mb->tail >= mb->head) ? mb->tail : mb->bufsize) - mb->head);
 }
 
+/* How many bytes exist after the wrap? */
+static int memio_buffer_wrapped_bytes(const struct memio_buffer *mb)
+{
+    return (mb->tail >= mb->head) ? 0 : mb->tail;
+}
+
 /* How many bytes can be written into the buffer without wrapping */
 static int memio_buffer_unused_contiguous(const struct memio_buffer *mb)
 {
@@ -399,13 +408,17 @@ void memio_PutReadResult(memio_Private *secret, int bytes_read)
     }
 }
 
-int memio_GetWriteParams(memio_Private *secret, const char **buf)
+void memio_GetWriteParams(memio_Private *secret,
+                          const char **buf1, unsigned int *len1,
+                          const char **buf2, unsigned int *len2)
 {
     struct memio_buffer* mb = &((PRFilePrivate *)secret)->writebuf;
     PR_ASSERT(mb->bufsize);
 
-    *buf = &mb->buf[mb->head];
-    return memio_buffer_used_contiguous(mb);
+    *buf1 = &mb->buf[mb->head];
+    *len1 = memio_buffer_used_contiguous(mb);
+    *buf2 = mb->buf;
+    *len2 = memio_buffer_wrapped_bytes(mb);
 }
 
 void memio_PutWriteResult(memio_Private *secret, int bytes_written)
@@ -415,8 +428,8 @@ void memio_PutWriteResult(memio_Private *secret, int bytes_written)
 
     if (bytes_written > 0) {
         mb->head += bytes_written;
-        if (mb->head == mb->bufsize)
-            mb->head = 0;
+        if (mb->head >= mb->bufsize)
+            mb->head -= mb->bufsize;
     } else if (bytes_written < 0) {
         mb->last_err = bytes_written;
     }
@@ -453,11 +466,13 @@ int main()
 
     CHECKEQ(memio_buffer_unused_contiguous(&mb), TEST_BUFLEN-1-5);
     CHECKEQ(memio_buffer_used_contiguous(&mb), 5);
+    CHECKEQ(memio_buffer_wrapped_bytes(&mb), 0);
 
     CHECKEQ(memio_buffer_put(&mb, "!", 1), 1);
 
     CHECKEQ(memio_buffer_unused_contiguous(&mb), 0);
     CHECKEQ(memio_buffer_used_contiguous(&mb), 6);
+    CHECKEQ(memio_buffer_wrapped_bytes(&mb), 0);
 
     CHECKEQ(memio_buffer_get(&mb, buf, 6), 6);
     CHECKEQ(memcmp(buf, "howdy!", 6), 0);
@@ -468,6 +483,7 @@ int main()
     CHECKEQ(memio_buffer_put(&mb, "01234", 5), 5);
 
     CHECKEQ(memio_buffer_used_contiguous(&mb), 1);
+    CHECKEQ(memio_buffer_wrapped_bytes(&mb), 4);
     CHECKEQ(memio_buffer_unused_contiguous(&mb), TEST_BUFLEN-1-5);
 
     CHECKEQ(memio_buffer_put(&mb, "5", 1), 1);
diff --git a/net/base/nss_memio.h b/net/base/nss_memio.h
index c93e91f..49d7cbc 100644
--- a/net/base/nss_memio.h
+++ b/net/base/nss_memio.h
@@ -68,10 +68,12 @@ int memio_GetReadParams(memio_Private *secret, char **buf);
 void memio_PutReadResult(memio_Private *secret, int bytes_read);
 
 /* Ask memio what data it has to send to the network.
- * Returns buffer space available to read into, or 0 if none available.
- * Puts current buffer position into *buf.
+ * Returns up to two buffers of data by writing the positions and lengths into
+ * |buf1|, |len1| and |buf2|, |len2|.
  */
-int memio_GetWriteParams(memio_Private *secret, const char **buf);
+void memio_GetWriteParams(memio_Private *secret,
+                          const char **buf1, unsigned int *len1,
+                          const char **buf2, unsigned int *len2);
 
 /* Tell memio how many bytes were sent to the network.
  * If bytes_written is < 0, it is treated as an NSPR error code.