From: Christopher Faulet <cfaulet@haproxy.com>
Date: Tue, 26 Sep 2023 16:05:29 +0000 (+0200)
Subject: MEDIUM: raw-sock: Specifiy amount of data to send via snd_pipe callback
X-Git-Tag: v2.9-dev8~31
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=91f1c5519a5a96dc12188d723a2bf0fe485d82fb;p=thirdparty%2Fhaproxy.git

MEDIUM: raw-sock: Specifiy amount of data to send via snd_pipe callback

When data were sent using the kernel splicing, we tried to send all data
with no restriction. Most of time it is valid. However, because the payload
representation may differ between the producer and the consumer, it is
important to be able to specify how must data to send via the splicing.

Of course, for performance reason, it is important to maximize amount of
data send via splicing at each call. However, on edge-cases, this now can be
limited.
---

diff --git a/include/haproxy/connection-t.h b/include/haproxy/connection-t.h
index bd08f1cb02..f6edc30dfc 100644
--- a/include/haproxy/connection-t.h
+++ b/include/haproxy/connection-t.h
@@ -388,7 +388,7 @@ struct xprt_ops {
 	size_t (*rcv_buf)(struct connection *conn, void *xprt_ctx, struct buffer *buf, size_t count, int flags); /* recv callback */
 	size_t (*snd_buf)(struct connection *conn, void *xprt_ctx, const struct buffer *buf, size_t count, int flags); /* send callback */
 	int  (*rcv_pipe)(struct connection *conn, void *xprt_ctx, struct pipe *pipe, unsigned int count); /* recv-to-pipe callback */
-	int  (*snd_pipe)(struct connection *conn, void *xprt_ctx, struct pipe *pipe); /* send-to-pipe callback */
+	int  (*snd_pipe)(struct connection *conn, void *xprt_ctx, struct pipe *pipe, unsigned int count); /* send-to-pipe callback */
 	void (*shutr)(struct connection *conn, void *xprt_ctx, int);    /* shutr function */
 	void (*shutw)(struct connection *conn, void *xprt_ctx, int);    /* shutw function */
 	void (*close)(struct connection *conn, void *xprt_ctx);         /* close the transport layer */
diff --git a/src/raw_sock.c b/src/raw_sock.c
index 31ca970f18..1287dc5e2e 100644
--- a/src/raw_sock.c
+++ b/src/raw_sock.c
@@ -160,7 +160,7 @@ int raw_sock_to_pipe(struct connection *conn, void *xprt_ctx, struct pipe *pipe,
 
 /* Send as many bytes as possible from the pipe to the connection's socket.
  */
-int raw_sock_from_pipe(struct connection *conn, void *xprt_ctx, struct pipe *pipe)
+int raw_sock_from_pipe(struct connection *conn, void *xprt_ctx, struct pipe *pipe, unsigned int count)
 {
 	int ret, done;
 
@@ -179,9 +179,12 @@ int raw_sock_from_pipe(struct connection *conn, void *xprt_ctx, struct pipe *pip
 		return 0;
 	}
 
+	if (unlikely(count > pipe->data))
+		count = pipe->data;
+
 	done = 0;
-	while (pipe->data) {
-		ret = splice(pipe->cons, NULL, conn->handle.fd, NULL, pipe->data,
+	while (count) {
+		ret = splice(pipe->cons, NULL, conn->handle.fd, NULL, count,
 			     SPLICE_F_MOVE|SPLICE_F_NONBLOCK);
 
 		if (ret <= 0) {
@@ -198,6 +201,7 @@ int raw_sock_from_pipe(struct connection *conn, void *xprt_ctx, struct pipe *pip
 		}
 
 		done += ret;
+		count -= ret;
 		pipe->data -= ret;
 	}
 	if (unlikely(conn->flags & CO_FL_WAIT_L4_CONN) && done) {