Support TCP Fast Openfast-open

New function gnutls_transport_set_fastopen() with example usage
in gnutls-cli (enabled with new --fastopen option).

1 files changed, 41 insertions, 0 deletions

diff --git a/lib/record.c b/lib/record.c
index 4e462b9eac..d33c9c25e1 100644
--- a/lib/record.c
+++ b/lib/record.c
@@ -146,6 +146,47 @@ gnutls_transport_set_int2(gnutls_session_t session,
 	    (gnutls_transport_ptr_t) (long) recv_int;
 }
 
+/**
+ * gnutls_transport_set_fastopen:
+ * @session: is a #gnutls_session_t type.
+ * @connect_addr: is the address we want to connect to
+ * @connect_addrlen: is the length of @connect_addr
+ *
+ * Enables TCP Fast Open (TFO) when @connect_addr and @connect_addrlen are set
+ * before the transport socket has been connected.
+ *
+ * TFO only works for TCP sockets of type AF_INET and AF_INET6.
+ * Not every OS supports TFO yet.
+ *
+ * Overriding push functions via gnutls_transport_set_vec_push_function()
+ * or gnutls_transport_set_push_function() effectively disables the internal
+ * support for TFO. In this case the user's write function has to care about
+ * the implementation of TFO.
+ *
+ * On GNU/Linux TFO has to be enabled at the system layer, that is
+ *   in /proc/sys/net/ipv4/tcp_fastopen, bit 0 has to be set.
+ *
+ * Since: 3.5.3
+ **/
+void
+gnutls_transport_set_fastopen(gnutls_session_t session,
+			  struct sockaddr *connect_addr, socklen_t connect_addrlen)
+{
+	gnutls_free(session->internals.connect_addr);
+
+	if (connect_addr && connect_addrlen) {
+		session->internals.connect_addr = gnutls_malloc(connect_addrlen);
+		if (session->internals.connect_addr) {
+			memcpy(session->internals.connect_addr, connect_addr, connect_addrlen);
+			session->internals.connect_addrlen = connect_addrlen;
+		} else
+			gnutls_assert();
+	} else {
+		session->internals.connect_addr = NULL;
+		session->internals.connect_addrlen = 0;
+	}
+}
+
 #if 0
 /* this will be a macro */
 /**