Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 46/61] ipv4: Invalidate the socket cached route on pmtu events if possible | Date | Tue, 12 Feb 2013 12:35:06 -0800 |
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3.7-stable review patch. If anyone has any objections, please let me know.
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From: Steffen Klassert <steffen.klassert@secunet.com>
[ Upstream commit 9cb3a50c5f63ed745702972f66eaee8767659acd ]
The route lookup in ipv4_sk_update_pmtu() might return a route different from the route we cached at the socket. This is because standart routes are per cpu, so each cpu has it's own struct rtable. This means that we do not invalidate the socket cached route if the NET_RX_SOFTIRQ is not served by the same cpu that the sending socket uses. As a result, the cached route reused until we disconnect.
With this patch we invalidate the socket cached route if possible. If the socket is owened by the user, we can't update the cached route directly. A followup patch will implement socket release callback functions for datagram sockets to handle this case.
Reported-by: Yurij M. Plotnikov <Yurij.Plotnikov@oktetlabs.ru> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ipv4/route.c | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-)
--- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -965,7 +965,7 @@ void ipv4_update_pmtu(struct sk_buff *sk } EXPORT_SYMBOL_GPL(ipv4_update_pmtu); -void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) +static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) { const struct iphdr *iph = (const struct iphdr *) skb->data; struct flowi4 fl4; @@ -978,6 +978,46 @@ void ipv4_sk_update_pmtu(struct sk_buff ip_rt_put(rt); } } + +void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) +{ + const struct iphdr *iph = (const struct iphdr *) skb->data; + struct flowi4 fl4; + struct rtable *rt; + struct dst_entry *dst; + + bh_lock_sock(sk); + rt = (struct rtable *) __sk_dst_get(sk); + + if (sock_owned_by_user(sk) || !rt) { + __ipv4_sk_update_pmtu(skb, sk, mtu); + goto out; + } + + __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); + + if (!__sk_dst_check(sk, 0)) { + rt = ip_route_output_flow(sock_net(sk), &fl4, sk); + if (IS_ERR(rt)) + goto out; + } + + __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu); + + dst = dst_check(&rt->dst, 0); + if (!dst) { + rt = ip_route_output_flow(sock_net(sk), &fl4, sk); + if (IS_ERR(rt)) + goto out; + + dst = &rt->dst; + } + + __sk_dst_set(sk, dst); + +out: + bh_unlock_sock(sk); +} EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); void ipv4_redirect(struct sk_buff *skb, struct net *net,
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