From befffe901649e2cc421d0d150c4379d01658cf6b Mon Sep 17 00:00:00 2001 From: Brian Haley Date: Tue, 12 Dec 2006 17:09:49 -0800 Subject: [PATCH] [IPV6]: Fix IPV6_UNICAST_HOPS getsockopt(). > Relevant standard (RFC 3493) notes: > > The IPV6_UNICAST_HOPS option may be used with getsockopt() to > determine the hop limit value that the system will use for subsequent > unicast packets sent via that socket. > > I don't reckon -1 could be the hop limit value. -1 means un-initialized. > IMHO, the value from > case 1 (if socket is connected to some destination), otherwise case 2 > (if bound to a scope interface) or ultimately the default hop limit > ought to be returned instead, as it will be most often correct, while > the current behavior is always wrong, unless setsockopt() has been used > first. I don't if some people may think doing a route lookup in > getsockopt might be overly expensive, but at least the two other cases > should be ok, particularly the last one. The following patch seems to work for me, but this code has behaved this way for a while, so don't know if it will break any existing apps. Signed-off-by: Brian Haley Signed-off-by: David S. Miller --- net/ipv6/ipv6_sockglue.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 1eafcfc95e81..352690e2ab82 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -978,12 +978,27 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname, break; case IPV6_UNICAST_HOPS: - val = np->hop_limit; - break; - case IPV6_MULTICAST_HOPS: - val = np->mcast_hops; + { + struct dst_entry *dst; + + if (optname == IPV6_UNICAST_HOPS) + val = np->hop_limit; + else + val = np->mcast_hops; + + dst = sk_dst_get(sk); + if (dst) { + if (val < 0) + val = dst_metric(dst, RTAX_HOPLIMIT); + if (val < 0) + val = ipv6_get_hoplimit(dst->dev); + dst_release(dst); + } + if (val < 0) + val = ipv6_devconf.hop_limit; break; + } case IPV6_MULTICAST_LOOP: val = np->mc_loop; -- GitLab