Commit e646b657 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by David S. Miller
Browse files

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



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: 45e4fd26 ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception")
Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Reported-by: default avatarWei 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: default avatarDavid S. Miller <davem@davemloft.net>
parent 33c162a9

include/net/ipv6.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

net/ipv6/datagram.c

+20 −0
Original line number Diff line number Diff line
@@ -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;

net/ipv6/udp.c

+1 −0
Original line number Diff line number Diff line
@@ -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,

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