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ipv6: Fixed source specific default route handling.

Browse source 
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>
This commit is contained in:
Markus Stenberg 2015-05-05 13:36:59 +03:00 committed by David S. Miller
parent 0a801445db
commit e16e888b52
2 changed files with 35 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

41
net/ipv6/ip6_output.c
View file

@ -886,6 +886,38 @@ static int ip6_dst_lookup_tail(struct sock *sk,
#endif
int err;
/* 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 (!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);
@ -893,15 +925,6 @@ static int ip6_dst_lookup_tail(struct sock *sk,
if (err)
goto out_err_release;
if (ipv6_addr_any(&fl6->saddr)) {
struct rt6_info *rt = (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;
}
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
/*
* Here if the dst entry we've looked up

5
net/ipv6/route.c
View file

@ -2245,9 +2245,10 @@ 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,