MINOR: conn_stream: add cs_send() as a default snd_buf() function

This function is generic and is able to automatically transfer data from a
buffer to the conn_stream's tx buffer. It does this automatically if the mux
doesn't define another snd_buf() function.

It cannot yet be used as-is with the conn_stream's txbuf without risking to
lose data on close since conn_streams need to be orphaned for this.

include/proto/connection.h

@@ -46,6 +46,7 @@ void conn_fd_handler(int fd);
 
 /* conn_stream functions */
 size_t __cs_recv(struct conn_stream *cs, struct buffer *buf, size_t count, int flags);
+size_t __cs_send(struct conn_stream *cs, struct buffer *buf, size_t count, int flags);
 
 /* receive a PROXY protocol header over a connection */
 int conn_recv_proxy(struct connection *conn, int flag);
@@ -314,6 +315,17 @@ static inline size_t cs_recv(struct conn_stream *cs, struct buffer *buf, size_t
 		return __cs_recv(cs, buf, count, flags);
 }
 
+/* conn_stream send function. Uses mux->snd_buf() if defined, otherwise
+ * falls back to __cs_send().
+ */
+static inline size_t cs_send(struct conn_stream *cs, struct buffer *buf, size_t count, int flags)
+{
+	if (cs->conn->mux->snd_buf)
+		return cs->conn->mux->snd_buf(cs, buf, count, flags);
+	else
+		return __cs_send(cs, buf, count, flags);
+}
+
 /***** Event manipulation primitives for use by DATA I/O callbacks *****/
 /* The __conn_* versions do not propagate to lower layers and are only meant
  * to be used by handlers called by the connection handler. The other ones

src/checks.c

@@ -771,7 +771,7 @@ static void __event_srv_chk_w(struct conn_stream *cs)
 		goto out;
 
 	if (b_data(&check->bo)) {
-		conn->mux->snd_buf(cs, &check->bo, b_data(&check->bo), 0);
+		cs_send(cs, &check->bo, b_data(&check->bo), 0);
 		b_realign_if_empty(&check->bo);
 		if (conn->flags & CO_FL_ERROR || cs->flags & CS_FL_ERROR) {
 			chk_report_conn_err(check, errno, 0);
@@ -2699,7 +2699,7 @@ static int tcpcheck_main(struct check *check)
 			int ret;
 
 			__cs_want_send(cs);
-			ret = conn->mux->snd_buf(cs, &check->bo, b_data(&check->bo), 0);
+			ret = cs_send(cs, &check->bo, b_data(&check->bo), 0);
 			b_realign_if_empty(&check->bo);
 
 			if (ret <= 0) {

src/connection.c

@@ -410,6 +410,17 @@ size_t __cs_recv(struct conn_stream *cs, struct buffer *buf, size_t count, int f
 	return ret;
 }
 
+/*
+ * default cs send() : this one is used when mux->snd_buf == NULL. It puts up to
+ * <count> bytes from <buf> into cs->txbuf. The number of bytes transferred is
+ * returned. Here we don't care if cs->txbuf is allocated or not. If not, it
+ * will be swapped with <buf>.
+ */
+size_t __cs_send(struct conn_stream *cs, struct buffer *buf, size_t count, int flags)
+{
+	return b_xfer(&cs->txbuf, buf, count);
+}
+
 /*
  * Get data length from tlv
  */

src/stream_interface.c

@@ -721,7 +721,7 @@ static struct task * si_cs_send(struct task *t, void *ctx, unsigned short state)
 		if (oc->flags & CF_STREAMER)
 			send_flag |= CO_SFL_STREAMER;
 
-		ret = conn->mux->snd_buf(cs, &oc->buf, co_data(oc), send_flag);
+		ret = cs_send(cs, &oc->buf, co_data(oc), send_flag);
 		if (ret > 0) {
 			did_send = 1;
 			oc->flags |= CF_WRITE_PARTIAL | CF_WROTE_DATA | CF_WRITE_EVENT;