From: Willy Tarreau <w@1wt.eu>
Date: Wed, 26 Aug 2020 08:21:06 +0000 (+0200)
Subject: MINOR: tcp: don't try to set/clear v6only on inherited sockets
X-Git-Tag: v2.3-dev4~77
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bbb284d6752c94817e37be9a26b5aea92e506612;p=thirdparty%2Fhaproxy.git

MINOR: tcp: don't try to set/clear v6only on inherited sockets

If a socket was already bound (inherited from a parent or retrieved from
a previous process), there's no point trying to change its IPV6_V6ONLY
state since it will fail. This is visible in strace as an EINVAL during
a reload when passing FDs.
---

diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 091772d40a..eb0e6689f7 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -974,9 +974,9 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
 	}
 #endif
 #if defined(IPV6_V6ONLY)
-	if (listener->options & LI_O_V6ONLY)
+	if (!ext && listener->options & LI_O_V6ONLY)
                 setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
-	else if (listener->options & LI_O_V4V6)
+	else if (!ext && listener->options & LI_O_V4V6)
                 setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &zero, sizeof(zero));
 #endif