ipv6: make IPV6_RECVPKTINFO work for ipv4 datagrams

We currently don't report IPV6_RECVPKTINFO in cmsg access ancillary data
for IPv4 datagrams on IPv6 sockets.

This patch splits the ip6_datagram_recv_ctl into two functions, one
which handles both protocol families, AF_INET and AF_INET6, while the
ip6_datagram_recv_specific_ctl only handles IPv6 cmsg data.

ip6_datagram_recv_*_ctl never reported back any errors, so we can make
them return void. Also provide a helper for protocols which don't offer dual
personality to further use ip6_datagram_recv_ctl, which is exported to
modules.

I needed to shuffle the code for ping around a bit to make it easier to
implement dual personality for ping ipv6 sockets in future.

Reported-by: Gert Doering <gert@space.net>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 233c3ab6aee4..1e586d92260e 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -477,12 +477,16 @@ try_again:
 		}
 		*addr_len = sizeof(*sin6);
 	}
+
+	if (np->rxopt.all)
+		ip6_datagram_recv_common_ctl(sk, msg, skb);
+
 	if (is_udp4) {
 		if (inet->cmsg_flags)
 			ip_cmsg_recv(msg, skb);
 	} else {
 		if (np->rxopt.all)
-			ip6_datagram_recv_ctl(sk, msg, skb);
+			ip6_datagram_recv_specific_ctl(sk, msg, skb);
 	}
 
 	err = copied;