[ 15/98] Revert "ip_gre: make ipgre_tunnel_xmit() not parse network header as IP unconditionally"

Greg Kroah-Hartman
2013-03-26T23:47:30Z

From: Timo Teräs <timo.teras@iki.fi>

[ Upstream commit 8c6216d7f118a128678270824b6a1286a63863ca ]

This reverts commit 412ed94744d16806fbec3bd250fd94e71cde5a1f.

The commit is wrong as tiph points to the outer IPv4 header which is
installed at ipgre_header() and not the inner one which is protocol dependant.

This commit broke succesfully opennhrp which use PF_PACKET socket with
ETH_P_NHRP protocol. Additionally ssl_addr is set to the link-layer
IPv4 address. This address is written by ipgre_header() to the skb
earlier, and this is the IPv4 header tiph should point to - regardless
of the inner protocol payload.

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/ip_gre.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -761,10 +761,7 @@ static netdev_tx_t ipgre_tunnel_xmit(str

if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
gre_hlen = 0;
- if (skb->protocol == htons(ETH_P_IP))
- tiph = (const struct iphdr *)skb->data;
- else
- tiph = &tunnel->parms.iph;
+ tiph = (const struct iphdr *)skb->data;
} else {
gre_hlen = tunnel->hlen;
tiph = &tunnel->parms.iph;