diff options
| author | Vadim Fedorenko <vfedorenko@novek.ru> | 2021-01-30 01:27:47 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-02-10 11:21:09 +0300 |
| commit | 9c7b01fc3e22c49466c1fd0a9024bfda6b76440e (patch) | |
| tree | 87e38fda142990fe764a5e7e7aba1c3eb6db5f2c | |
| parent | ada82f9940e92650221b677a46afd086632ed1c7 (diff) | |
| download | linux-9c7b01fc3e22c49466c1fd0a9024bfda6b76440e.tar.xz | |
net: ip_tunnel: fix mtu calculation
commit 28e104d00281ade30250b24e098bf50887671ea4 upstream.
dev->hard_header_len for tunnel interface is set only when header_ops
are set too and already contains full overhead of any tunnel encapsulation.
That's why there is not need to use this overhead twice in mtu calc.
Fixes: fdafed459998 ("ip_gre: set dev->hard_header_len and dev->needed_headroom properly")
Reported-by: Slava Bacherikov <mail@slava.cc>
Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
Link: https://lore.kernel.org/r/1611959267-20536-1-git-send-email-vfedorenko@novek.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ipv4/ip_tunnel.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index 1cad731039c3..bdd073ea300a 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -330,7 +330,7 @@ static int ip_tunnel_bind_dev(struct net_device *dev) } dev->needed_headroom = t_hlen + hlen; - mtu -= (dev->hard_header_len + t_hlen); + mtu -= t_hlen; if (mtu < IPV4_MIN_MTU) mtu = IPV4_MIN_MTU; @@ -360,7 +360,7 @@ static struct ip_tunnel *ip_tunnel_create(struct net *net, nt = netdev_priv(dev); t_hlen = nt->hlen + sizeof(struct iphdr); dev->min_mtu = ETH_MIN_MTU; - dev->max_mtu = IP_MAX_MTU - dev->hard_header_len - t_hlen; + dev->max_mtu = IP_MAX_MTU - t_hlen; ip_tunnel_add(itn, nt); return nt; @@ -502,12 +502,11 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb, const struct iphdr *inner_iph) { struct ip_tunnel *tunnel = netdev_priv(dev); - int pkt_size = skb->len - tunnel->hlen - dev->hard_header_len; + int pkt_size = skb->len - tunnel->hlen; int mtu; if (df) - mtu = dst_mtu(&rt->dst) - dev->hard_header_len - - sizeof(struct iphdr) - tunnel->hlen; + mtu = dst_mtu(&rt->dst) - (sizeof(struct iphdr) + tunnel->hlen); else mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; @@ -935,7 +934,7 @@ int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict) { struct ip_tunnel *tunnel = netdev_priv(dev); int t_hlen = tunnel->hlen + sizeof(struct iphdr); - int max_mtu = IP_MAX_MTU - dev->hard_header_len - t_hlen; + int max_mtu = IP_MAX_MTU - t_hlen; if (new_mtu < ETH_MIN_MTU) return -EINVAL; @@ -1112,10 +1111,9 @@ int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[], mtu = ip_tunnel_bind_dev(dev); if (tb[IFLA_MTU]) { - unsigned int max = IP_MAX_MTU - dev->hard_header_len - nt->hlen; + unsigned int max = IP_MAX_MTU - (nt->hlen + sizeof(struct iphdr)); - mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU, - (unsigned int)(max - sizeof(struct iphdr))); + mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU, max); } err = dev_set_mtu(dev, mtu); |