After commit 33c162a980fe ("ipv6: datagram: Update dst cache of a
connected datagram sk during pmtu update"), when the error occurs on
sending datagram in udpv6_sendmsg() due to ICMPV6_PKT_TOOBIG type,
error handler can trigger the following path and call ip6_dst_store():
udpv6_err()
ip6_sk_update_pmtu()
ip6_datagram_dst_update()
ip6_dst_lookup_flow(), can create a RTF_CACHE clone
...
ip6_dst_store()
It can happen before a connected UDP socket invokes ip6_dst_store()
in the end of udpv6_sendmsg(), on destination release, as a result,
the last one changes dst to the old one, preventing getting updated
dst cache on the next udpv6_sendmsg() call.
This patch moves ip6_dst_store() in udpv6_sendmsg(), so that it is
invoked after ip6_sk_dst_lookup_flow() and before udp_v6_send_skb().
Signed-off-by: Alexey Kodanev <alexey.koda...@oracle.com>
---
net/ipv6/udp.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 52e3ea0..0d413c6 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1299,6 +1299,16 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg,
size_t len)
if (ipc6.hlimit < 0)
ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
+ if (connected)
+ ip6_dst_store(sk, dst,
+ ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr) ?
+ &sk->sk_v6_daddr : NULL,
+#ifdef CONFIG_IPV6_SUBTREES
+ ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
+ &np->saddr :
+#endif
+ NULL);
+
if (msg->msg_flags&MSG_CONFIRM)
goto do_confirm;
back_from_confirm:
@@ -1350,18 +1360,8 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg,
size_t len)
release_dst:
if (dst) {
- if (connected) {
- ip6_dst_store(sk, dst,
- ipv6_addr_equal(&fl6.daddr,
&sk->sk_v6_daddr) ?
- &sk->sk_v6_daddr : NULL,
-#ifdef CONFIG_IPV6_SUBTREES
- ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
- &np->saddr :
-#endif
- NULL);
- } else {
+ if (!connected)
dst_release(dst);
- }
dst = NULL;
}
--
1.8.3.1
