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ipv6: udp: Do a route lookup and update during release_cb

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This patch adds a release_cb for UDPv6.  It does a route lookup
and updates sk->sk_dst_cache if it is needed.  It picks up the
left-over job from ip6_sk_update_pmtu() if the sk was owned
by user during the pmtu update.

It takes a rcu_read_lock to protect the __sk_dst_get() operations
because another thread may do ip6_dst_store() without taking the
sk lock (e.g. sendmsg).

Fixes: 45e4fd2668 ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reported-by: Wei Wang <weiwan@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Martin KaFai Lau 2016-04-11 15:29:37 -07:00 committed by David S. Miller
parent 33c162a980
commit e646b657f6
3 changed files with 22 additions and 0 deletions
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1
include/net/ipv6.h
View File

@ -960,6 +960,7 @@ int ip6_datagram_connect(struct sock *sk, struct sockaddr *addr, int addr_len);
int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *addr,
int addr_len);
int ip6_datagram_dst_update(struct sock *sk, bool fix_sk_saddr);
void ip6_datagram_release_cb(struct sock *sk);
int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
int *addr_len);

20
net/ipv6/datagram.c
View File

@ -119,6 +119,26 @@ out:
return err;
}
void ip6_datagram_release_cb(struct sock *sk)
{
struct dst_entry *dst;
if (ipv6_addr_v4mapped(&sk->sk_v6_daddr))
return;
rcu_read_lock();
dst = __sk_dst_get(sk);
if (!dst || !dst->obsolete ||
dst->ops->check(dst, inet6_sk(sk)->dst_cookie)) {
rcu_read_unlock();
return;
}
rcu_read_unlock();
ip6_datagram_dst_update(sk, false);
}
EXPORT_SYMBOL_GPL(ip6_datagram_release_cb);
static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;

1
net/ipv6/udp.c
View File

@ -1539,6 +1539,7 @@ struct proto udpv6_prot = {
.sendmsg = udpv6_sendmsg,
.recvmsg = udpv6_recvmsg,
.backlog_rcv = __udpv6_queue_rcv_skb,
.release_cb = ip6_datagram_release_cb,
.hash = udp_lib_hash,
.unhash = udp_lib_unhash,
.rehash = udp_v6_rehash,