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| author | Hangbin Liu <liuhangbin@gmail.com> | 2021-07-09 11:45:02 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-28 11:13:46 +0200 |
| commit | be680f4bf72231e75383a097981016c2b1ab0197 (patch) | |
| tree | 8a1d7362ae2e8ea52362bd397e21ebbdc9d222db /net | |
| parent | dd1f607cad1f3be1880193521bee2bbd48354a23 (diff) | |
| download | linux-be680f4bf72231e75383a097981016c2b1ab0197.tar.gz linux-be680f4bf72231e75383a097981016c2b1ab0197.tar.bz2 linux-be680f4bf72231e75383a097981016c2b1ab0197.zip | |
net: ip_tunnel: fix mtu calculation for ETHER tunnel devices
commit 9992a078b1771da354ac1f9737e1e639b687caa2 upstream.
Commit 28e104d00281 ("net: ip_tunnel: fix mtu calculation") removed
dev->hard_header_len subtraction when calculate MTU for tunnel devices
as there is an overhead for device that has header_ops.
But there are ETHER tunnel devices, like gre_tap or erspan, which don't
have header_ops but set dev->hard_header_len during setup. This makes
pkts greater than (MTU - ETH_HLEN) could not be xmited. Fix it by
subtracting the ETHER tunnel devices' dev->hard_header_len for MTU
calculation.
Fixes: 28e104d00281 ("net: ip_tunnel: fix mtu calculation")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/ip_tunnel.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index bdd073ea300a..30e93b4f831f 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 -= t_hlen; + mtu -= t_hlen + (dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0); if (mtu < IPV4_MIN_MTU) mtu = IPV4_MIN_MTU; @@ -361,6 +361,9 @@ static struct ip_tunnel *ip_tunnel_create(struct net *net, t_hlen = nt->hlen + sizeof(struct iphdr); dev->min_mtu = ETH_MIN_MTU; dev->max_mtu = IP_MAX_MTU - t_hlen; + if (dev->type == ARPHRD_ETHER) + dev->max_mtu -= dev->hard_header_len; + ip_tunnel_add(itn, nt); return nt; @@ -502,13 +505,18 @@ 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; + int pkt_size; int mtu; - if (df) + pkt_size = skb->len - tunnel->hlen; + pkt_size -= dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0; + + if (df) { mtu = dst_mtu(&rt->dst) - (sizeof(struct iphdr) + tunnel->hlen); - else + mtu -= dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0; + } else { mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; + } skb_dst_update_pmtu_no_confirm(skb, mtu); @@ -936,6 +944,9 @@ int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict) int t_hlen = tunnel->hlen + sizeof(struct iphdr); int max_mtu = IP_MAX_MTU - t_hlen; + if (dev->type == ARPHRD_ETHER) + max_mtu -= dev->hard_header_len; + if (new_mtu < ETH_MIN_MTU) return -EINVAL; @@ -1113,6 +1124,9 @@ int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[], if (tb[IFLA_MTU]) { unsigned int max = IP_MAX_MTU - (nt->hlen + sizeof(struct iphdr)); + if (dev->type == ARPHRD_ETHER) + max -= dev->hard_header_len; + mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU, max); } |