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, 1 insertions, 3 deletions

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 7024a874e901..0a00f449de5e 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1002,10 +1002,8 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
 		release_sock(sk);
 
 		if (skb) {
-			int err = ip6_datagram_recv_ctl(sk, &msg, skb);
+			ip6_datagram_recv_ctl(sk, &msg, skb);
 			kfree_skb(skb);
-			if (err)
-				return err;
 		} else {
 			if (np->rxopt.bits.rxinfo) {
 				struct in6_pktinfo src_info;