IPv6: Complete IPV6_DONTFRAG support

Finally add support to detect a local IPV6_DONTFRAG event
and return the relevant data to the user if they've enabled
IPV6_RECVPATHMTU on the socket.  The next recvmsg() will
return no data, but have an IPV6_PATHMTU as ancillary data.

Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 39e3665d9460..2850e35cee3d 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -335,6 +335,9 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
         if (flags & MSG_ERRQUEUE)
                 return ipv6_recv_error(sk, msg, len);
 
+        if (np->rxpmtu && np->rxopt.bits.rxpmtu)
+                return ipv6_recv_rxpmtu(sk, msg, len);
+
 try_again:
         skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
                                   &peeked, &err);