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- From e16e888b525503be05b3aea64190e8b3bdef44d0 Mon Sep 17 00:00:00 2001
- From: Markus Stenberg <markus.stenberg@iki.fi>
- Date: Tue, 5 May 2015 13:36:59 +0300
- Subject: [PATCH] ipv6: Fixed source specific default route handling.
- If there are only IPv6 source specific default routes present, the
- host gets -ENETUNREACH on e.g. connect() because ip6_dst_lookup_tail
- calls ip6_route_output first, and given source address any, it fails,
- and ip6_route_get_saddr is never called.
- The change is to use the ip6_route_get_saddr, even if the initial
- ip6_route_output fails, and then doing ip6_route_output _again_ after
- we have appropriate source address available.
- Note that this is '99% fix' to the problem; a correct fix would be to
- do route lookups only within addrconf.c when picking a source address,
- and never call ip6_route_output before source address has been
- populated.
- Signed-off-by: Markus Stenberg <markus.stenberg@iki.fi>
- Signed-off-by: David S. Miller <davem@davemloft.net>
- ---
- net/ipv6/ip6_output.c | 39 +++++++++++++++++++++++++++++++--------
- net/ipv6/route.c | 5 +++--
- 2 files changed, 34 insertions(+), 10 deletions(-)
- --- a/net/ipv6/ip6_output.c
- +++ b/net/ipv6/ip6_output.c
- @@ -906,21 +906,45 @@ static int ip6_dst_lookup_tail(struct so
- #endif
- int err;
-
- - if (*dst == NULL)
- - *dst = ip6_route_output(net, sk, fl6);
- -
- - if ((err = (*dst)->error))
- - goto out_err_release;
- + /* The correct way to handle this would be to do
- + * ip6_route_get_saddr, and then ip6_route_output; however,
- + * the route-specific preferred source forces the
- + * ip6_route_output call _before_ ip6_route_get_saddr.
- + *
- + * In source specific routing (no src=any default route),
- + * ip6_route_output will fail given src=any saddr, though, so
- + * that's why we try it again later.
- + */
- + if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
- + struct rt6_info *rt;
- + bool had_dst = *dst != NULL;
-
- - if (ipv6_addr_any(&fl6->saddr)) {
- - struct rt6_info *rt = (struct rt6_info *) *dst;
- + if (!had_dst)
- + *dst = ip6_route_output(net, sk, fl6);
- + rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
- err = ip6_route_get_saddr(net, rt, &fl6->daddr,
- sk ? inet6_sk(sk)->srcprefs : 0,
- &fl6->saddr);
- if (err)
- goto out_err_release;
- +
- + /* If we had an erroneous initial result, pretend it
- + * never existed and let the SA-enabled version take
- + * over.
- + */
- + if (!had_dst && (*dst)->error) {
- + dst_release(*dst);
- + *dst = NULL;
- + }
- }
-
- + if (!*dst)
- + *dst = ip6_route_output(net, sk, fl6);
- +
- + err = (*dst)->error;
- + if (err)
- + goto out_err_release;
- +
- #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
- /*
- * Here if the dst entry we've looked up
- --- a/net/ipv6/route.c
- +++ b/net/ipv6/route.c
- @@ -2184,9 +2184,10 @@ int ip6_route_get_saddr(struct net *net,
- unsigned int prefs,
- struct in6_addr *saddr)
- {
- - struct inet6_dev *idev = ip6_dst_idev((struct dst_entry *)rt);
- + struct inet6_dev *idev =
- + rt ? ip6_dst_idev((struct dst_entry *)rt) : NULL;
- int err = 0;
- - if (rt->rt6i_prefsrc.plen)
- + if (rt && rt->rt6i_prefsrc.plen)
- *saddr = rt->rt6i_prefsrc.addr;
- else
- err = ipv6_dev_get_saddr(net, idev ? idev->dev : NULL,
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