[PATCH net] ip_gre: fix msg_name parsing for recvfrom/recvmsg

["Timo Teräs" <timo.teras@iki.fi>]

ipgre_header_parse() needs to parse the tunnel's ip header for getting
the link-layer addresses, and uses mac_header to get the header. This
fixes setting mac_header on the receive path to original behaviour.

Bug added in commit c54419321455 (GRE: Refactor GRE tunneling code.)

Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
---
Alternate would be to do skb_reset_inner_headers() in ip_tunnel_rcv() and
update ipgre_header_parse() to use skb_inner_network_header(). Though, then
inner would then be referring to the "outer" headers.

If applied as-is, should go to -stable too.

 net/ipv4/ip_gre.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index d7aea4c..cc2c7f1 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -217,6 +217,7 @@ static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
 				  iph->saddr, iph->daddr, tpi->key);
 
 	if (tunnel) {
+		skb->mac_header = skb->network_header;
 		ip_tunnel_rcv(tunnel, skb, tpi, log_ecn_error);
 		return PACKET_RCVD;
 	}
-- 
1.8.5.1