From 58a4782449c5882f61882396ef18cc34c7dc1269 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 16 Dec 2013 06:31:23 -0800 Subject: [PATCH] ipv6: sit: update mtu check to take care of gso packets While testing my changes for TSO support in SIT devices, I was using sit0 tunnel which appears to include nopmtudisc flag. But using : ip tun add sittun mode sit remote $REMOTE_IPV4 local $LOCAL_IPV4 \ dev $IFACE We get a tunnel which rejects too long packets because of the mtu check which is not yet GSO aware. erd:~# ip tunnel sittun: ipv6/ip remote 10.246.17.84 local 10.246.17.83 ttl inherit 6rd-prefix 2002::/16 sit0: ipv6/ip remote any local any ttl 64 nopmtudisc 6rd-prefix 2002::/16 This patch is based on an excellent report from Michal Shmidt. In the future, we probably want to extend the MTU check to do the right thing for GSO packets... Fixes: ("61c1db7fae21 ipv6: sit: add GSO/TSO support") Reported-by: Michal Schmidt Signed-off-by: Eric Dumazet Tested-by: Michal Schmidt Signed-off-by: David S. Miller --- net/ipv6/sit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 366fbba3359..a710fdec42d 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -924,7 +924,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb, if (tunnel->parms.iph.daddr && skb_dst(skb)) skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); - if (skb->len > mtu) { + if (skb->len > mtu && !skb_is_gso(skb)) { icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); ip_rt_put(rt); goto tx_error; -- 2.43.2