From: Willy Tarreau <w@1wt.eu>
Date: Fri, 17 Mar 2023 15:09:14 +0000 (+0100)
Subject: MINOR: mux-h2: set CO_SFL_MSG_MORE when sending multiple buffers
X-Git-Tag: v2.8-dev6~47
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=464fa06e9adbadc0c93fa5866d8fa4f55d69c2eb;p=thirdparty%2Fhaproxy.git

MINOR: mux-h2: set CO_SFL_MSG_MORE when sending multiple buffers

Traces show that sendto() rarely has MSG_MORE on H2 despite sending
multiple buffers. The reason is that the loop iterating over the buffer
ring doesn't have this info and doesn't pass it down.

But now we know how many buffers are left to be sent, so we know whether
or not the current buffer is the last one. As such we can set this flag
for all buffers but the last one.
---

diff --git a/src/mux_h2.c b/src/mux_h2.c
index f5fa27f485..c2c9b21426 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -3798,6 +3798,7 @@ static int h2_send(struct h2c *h2c)
 		unsigned int flags = 0;
 		unsigned int released = 0;
 		struct buffer *buf;
+		uint to_send;
 
 		/* fill as much as we can into the current buffer */
 		while (((h2c->flags & (H2_CF_MUX_MFULL|H2_CF_MUX_MALLOC)) == 0) && !done)
@@ -3813,7 +3814,8 @@ static int h2_send(struct h2c *h2c)
 		if (h2c->flags & (H2_CF_MUX_MFULL | H2_CF_DEM_MROOM))
 			flags |= CO_SFL_MSG_MORE;
 
-		if (!br_single(h2c->mbuf)) {
+		to_send = br_count(h2c->mbuf);
+		if (to_send > 1) {
 			/* usually we want to emit small TLS records to speed
 			 * up the decoding on the client. That's what is being
 			 * done by default. However if there is more than one
@@ -3825,12 +3827,14 @@ static int h2_send(struct h2c *h2c)
 
 		for (buf = br_head(h2c->mbuf); b_size(buf); buf = br_del_head(h2c->mbuf)) {
 			if (b_data(buf)) {
-				int ret = conn->xprt->snd_buf(conn, conn->xprt_ctx, buf, b_data(buf), flags);
+				int ret = conn->xprt->snd_buf(conn, conn->xprt_ctx, buf, b_data(buf),
+							      flags | (to_send > 1 ? CO_SFL_MSG_MORE : 0));
 				if (!ret) {
 					done = 1;
 					break;
 				}
 				sent = 1;
+				to_send--;
 				TRACE_DATA("sent data", H2_EV_H2C_SEND, h2c->conn, 0, buf, (void*)(long)ret);
 				b_del(buf, ret);
 				if (b_data(buf)) {