4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Xin Long <lucien.xin@xxxxxxxxx>
[ Upstream commit d41bb33ba33b8f8debe54ed36be6925eb496e354 ]
Now when updating mtu in tx path, it doesn't consider ARPHRD_ETHER tunnel
device, like ip6gre_tap tunnel, for which it should also subtract ether
header to get the correct mtu.
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/ip6_tunnel.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1042,6 +1042,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, st
struct dst_entry *dst = NULL, *ndst = NULL;
struct net_device *tdev;
int mtu;
+ unsigned int eth_hlen = t->dev->type == ARPHRD_ETHER ? ETH_HLEN : 0;
unsigned int psh_hlen = sizeof(struct ipv6hdr) + t->encap_hlen;
unsigned int max_headroom = psh_hlen;
bool use_cache = false;
@@ -1120,7 +1121,7 @@ route_lookup:
t->parms.name);
goto tx_err_dst_release;
}
- mtu = dst_mtu(dst) - psh_hlen - t->tun_hlen;
+ mtu = dst_mtu(dst) - eth_hlen - psh_hlen - t->tun_hlen;
if (encap_limit >= 0) {
max_headroom += 8;
mtu -= 8;
@@ -1129,7 +1130,7 @@ route_lookup:
mtu = IPV6_MIN_MTU;
if (skb_dst(skb) && !t->parms.collect_md)
skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
- if (skb->len - t->tun_hlen > mtu && !skb_is_gso(skb)) {
+ if (skb->len - t->tun_hlen - eth_hlen > mtu && !skb_is_gso(skb)) {
*pmtu = mtu;
err = -EMSGSIZE;
goto tx_err_dst_release;