From: Christopher Faulet <cfaulet@haproxy.com>
Date: Mon, 22 Mar 2021 14:07:51 +0000 (+0100)
Subject: MINOR: stream: Don't trigger errors on destructive HTTP upgrades
X-Git-Tag: v2.4-dev15~61
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f0d7eb2f4f3112a363e35fd040614a2af1179e43;p=thirdparty%2Fhaproxy.git

MINOR: stream: Don't trigger errors on destructive HTTP upgrades

When a TCP stream is upgraded to H2 stream, a destructive upgrade is
performed. It means the TCP stream is silently released while a new one is
created. It is of course more complicated but it is what we observe from the
stream point of view.

That was performed by returning an error when the backend was set. It is
neither really elegant nor accurate. So now, instead of returning an error
from stream_set_backend() in case of destructive HTTP upgrades, the TCP
stream processing is aborted and no error is reported. However, the result
is more or less the same.
---

diff --git a/src/proxy.c b/src/proxy.c
index 335bbafe07..c9a0384135 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -2176,23 +2176,27 @@ int stream_set_backend(struct stream *s, struct proxy *be)
 					    &s->si[0].wait_event);
 				if (conn_upgrade_mux_fe(conn, cs, &s->req.buf, ist(""), PROTO_MODE_HTTP)  == -1)
 					return 0;
+
+				s->req.flags &= ~(CF_READ_PARTIAL|CF_AUTO_CONNECT);
+				s->req.total = 0;
+				s->flags |= SF_IGNORE;
 				if (strcmp(conn->mux->name, "H2") == 0) {
 					/* For HTTP/2, destroy the conn_stream,
-					 * disable logging, and pretend that we
-					 * failed, to that the stream is
-					 * silently destroyed. The new mux
-					 * will create new streams.
+					 * disable logging, and abort the stream
+					 * process. Thus it will be silently
+					 * destroyed. The new mux will create
+					 * new streams.
 					 */
 					cs_free(cs);
 					si_detach_endpoint(&s->si[0]);
 					s->logs.logwait = 0;
 					s->logs.level = 0;
-					s->flags |= SF_IGNORE;
-					return 0;
+					channel_abort(&s->req);
+					channel_abort(&s->res);
+					s->req.analysers &= AN_REQ_FLT_END;
+					s->req.analyse_exp = TICK_ETERNITY;
+					return 1;
 				}
-				s->req.flags &= ~(CF_READ_PARTIAL|CF_AUTO_CONNECT);
-				s->req.total = 0;
-				s->flags |= SF_IGNORE;
 			}
 		}
 		else if (IS_HTX_STRM(s) && be->mode != PR_MODE_HTTP) {
diff --git a/src/stream.c b/src/stream.c
index b0c2bab372..9ef292d928 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -1109,11 +1109,21 @@ static int process_switching_rules(struct stream *s, struct channel *req, int an
 		/* To ensure correct connection accounting on the backend, we
 		 * have to assign one if it was not set (eg: a listen). This
 		 * measure also takes care of correctly setting the default
-		 * backend if any.
+		 * backend if any. Don't do anything if an upgrade is already in
+		 * progress.
 		 */
-		if (!(s->flags & SF_BE_ASSIGNED))
+		if (!(s->flags & (SF_BE_ASSIGNED|SF_IGNORE)))
 			if (!stream_set_backend(s, fe->defbe.be ? fe->defbe.be : s->be))
 				goto sw_failed;
+
+		/* No backend assigned but no error reported. It happens when a
+		 * TCP stream is upgraded to HTTP/2.
+		 */
+		if ((s->flags & (SF_BE_ASSIGNED|SF_IGNORE)) == SF_IGNORE) {
+			DBG_TRACE_DEVEL("leaving with no backend because of a destructive upgrade", STRM_EV_STRM_ANA, s);
+			return 0;
+		}
+
 	}
 
 	/* we don't want to run the TCP or HTTP filters again if the backend has not changed */