From d41bb33ba33b8f8debe54ed36be6925eb496e354 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 28 Sep 2017 13:24:07 +0800 Subject: [PATCH] ip6_tunnel: update mtu properly for ARPHRD_ETHER tunnel device in tx path 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 Signed-off-by: David S. Miller --- net/ipv6/ip6_tunnel.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index f2f21c24915f..a1c24443cd9e 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1043,6 +1043,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield, 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; @@ -1124,7 +1125,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield, 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; @@ -1133,7 +1134,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield, 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;