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| author | Craig Gallek <kraig@google.com> | 2016-04-12 13:11:25 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-04-14 21:14:03 -0400 |
| commit | d894ba18d4e449b3a7f6eb491f16c9e02933736e (patch) | |
| tree | 9a0987a506c9caa46daf10a58abd2bc141b06745 /net | |
| parent | c5b5343cfbc9f46af65033fa4f407d7b7d98371d (diff) | |
| download | linux-d894ba18d4e449b3a7f6eb491f16c9e02933736e.tar.bz2 | |
soreuseport: fix ordering for mixed v4/v6 sockets
With the SO_REUSEPORT socket option, it is possible to create sockets
in the AF_INET and AF_INET6 domains which are bound to the same IPv4 address.
This is only possible with SO_REUSEPORT and when not using IPV6_V6ONLY on
the AF_INET6 sockets.
Prior to the commits referenced below, an incoming IPv4 packet would
always be routed to a socket of type AF_INET when this mixed-mode was used.
After those changes, the same packet would be routed to the most recently
bound socket (if this happened to be an AF_INET6 socket, it would
have an IPv4 mapped IPv6 address).
The change in behavior occurred because the recent SO_REUSEPORT optimizations
short-circuit the socket scoring logic as soon as they find a match. They
did not take into account the scoring logic that favors AF_INET sockets
over AF_INET6 sockets in the event of a tie.
To fix this problem, this patch changes the insertion order of AF_INET
and AF_INET6 addresses in the TCP and UDP socket lists when the sockets
have SO_REUSEPORT set. AF_INET sockets will be inserted at the head of the
list and AF_INET6 sockets with SO_REUSEPORT set will always be inserted at
the tail of the list. This will force AF_INET sockets to always be
considered first.
Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection")
Fixes: 125e80b88687 ("soreuseport: fast reuseport TCP socket selection")
Reported-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/udp.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 08eed5e16df0..a2e7f55a1f61 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -339,8 +339,13 @@ found: hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash); spin_lock(&hslot2->lock); - hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node, - &hslot2->head); + if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport && + sk->sk_family == AF_INET6) + hlist_nulls_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node, + &hslot2->head); + else + hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node, + &hslot2->head); hslot2->count++; spin_unlock(&hslot2->lock); } |