Commit c9a166be authored by Xin Long's avatar Xin Long Committed by Greg Kroah-Hartman

ip6_gre: update mtu properly in ip6gre_err


[ Upstream commit 5c25f30c ]

Now when probessing ICMPV6_PKT_TOOBIG, ip6gre_err only subtracts the
offset of gre header from mtu info. The expected mtu of gre device
should also subtract gre header. Otherwise, the next packets still
can't be sent out.

Jianlin found this issue when using the topo:
  client(ip6gre)<---->(nic1)route(nic2)<----->(ip6gre)server

and reducing nic2's mtu, then both tcp and sctp's performance with
big size data became 0.

This patch is to fix it by also subtracting grehdr (tun->tun_hlen)
from mtu info when updating gre device's mtu in ip6gre_err(). It
also needs to subtract ETH_HLEN if gre dev'type is ARPHRD_ETHER.
Reported-by: default avatarJianlin Shi <jishi@redhat.com>
Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b076d251
...@@ -432,7 +432,9 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt, ...@@ -432,7 +432,9 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
} }
break; break;
case ICMPV6_PKT_TOOBIG: case ICMPV6_PKT_TOOBIG:
mtu = be32_to_cpu(info) - offset; mtu = be32_to_cpu(info) - offset - t->tun_hlen;
if (t->dev->type == ARPHRD_ETHER)
mtu -= ETH_HLEN;
if (mtu < IPV6_MIN_MTU) if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU; mtu = IPV6_MIN_MTU;
t->dev->mtu = mtu; t->dev->mtu = mtu;
......
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