1 From e16e888b525503be05b3aea64190e8b3bdef44d0 Mon Sep 17 00:00:00 2001
2 From: Markus Stenberg <markus.stenberg@iki.fi>
3 Date: Tue, 5 May 2015 13:36:59 +0300
4 Subject: [PATCH] ipv6: Fixed source specific default route handling.
6 If there are only IPv6 source specific default routes present, the
7 host gets -ENETUNREACH on e.g. connect() because ip6_dst_lookup_tail
8 calls ip6_route_output first, and given source address any, it fails,
9 and ip6_route_get_saddr is never called.
11 The change is to use the ip6_route_get_saddr, even if the initial
12 ip6_route_output fails, and then doing ip6_route_output _again_ after
13 we have appropriate source address available.
15 Note that this is '99% fix' to the problem; a correct fix would be to
16 do route lookups only within addrconf.c when picking a source address,
17 and never call ip6_route_output before source address has been
20 Signed-off-by: Markus Stenberg <markus.stenberg@iki.fi>
21 Signed-off-by: David S. Miller <davem@davemloft.net>
23 net/ipv6/ip6_output.c | 39 +++++++++++++++++++++++++++++++--------
24 net/ipv6/route.c | 5 +++--
25 2 files changed, 34 insertions(+), 10 deletions(-)
27 diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
28 index 7fde1f2..c217775 100644
29 --- a/net/ipv6/ip6_output.c
30 +++ b/net/ipv6/ip6_output.c
31 @@ -897,21 +897,45 @@ static int ip6_dst_lookup_tail(struct so
36 - *dst = ip6_route_output(net, sk, fl6);
38 - if ((err = (*dst)->error))
39 - goto out_err_release;
40 + /* The correct way to handle this would be to do
41 + * ip6_route_get_saddr, and then ip6_route_output; however,
42 + * the route-specific preferred source forces the
43 + * ip6_route_output call _before_ ip6_route_get_saddr.
45 + * In source specific routing (no src=any default route),
46 + * ip6_route_output will fail given src=any saddr, though, so
47 + * that's why we try it again later.
49 + if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
50 + struct rt6_info *rt;
51 + bool had_dst = *dst != NULL;
53 - if (ipv6_addr_any(&fl6->saddr)) {
54 - struct rt6_info *rt = (struct rt6_info *) *dst;
56 + *dst = ip6_route_output(net, sk, fl6);
57 + rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
58 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
59 sk ? inet6_sk(sk)->srcprefs : 0,
64 + /* If we had an erroneous initial result, pretend it
65 + * never existed and let the SA-enabled version take
68 + if (!had_dst && (*dst)->error) {
75 + *dst = ip6_route_output(net, sk, fl6);
77 + err = (*dst)->error;
79 + goto out_err_release;
81 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
83 * Here if the dst entry we've looked up
84 --- a/net/ipv6/route.c
85 +++ b/net/ipv6/route.c
86 @@ -2215,9 +2215,10 @@ int ip6_route_get_saddr(struct net *net,
88 struct in6_addr *saddr)
90 - struct inet6_dev *idev = ip6_dst_idev((struct dst_entry *)rt);
91 + struct inet6_dev *idev =
92 + rt ? ip6_dst_idev((struct dst_entry *)rt) : NULL;
94 - if (rt->rt6i_prefsrc.plen)
95 + if (rt && rt->rt6i_prefsrc.plen)
96 *saddr = rt->rt6i_prefsrc.addr;
98 err = ipv6_dev_get_saddr(net, idev ? idev->dev : NULL,