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authorXin Long <lucien.xin@gmail.com>2018-08-05 22:46:07 +0800
committerDavid S. Miller <davem@davemloft.net>2018-08-05 17:35:02 -0700
commit82a40777de12728dedf4075453b694f0d1baee80 (patch)
tree600acf57599f3906a88bc39adac0f461f0edbdf2
parente70a3aad44cc8b24986687ffc98c4a4f6ecf25ea (diff)
download96b-common-82a40777de12728dedf4075453b694f0d1baee80.tar.gz
ip6_tunnel: use the right value for ipv4 min mtu check in ip6_tnl_xmit
According to RFC791, 68 bytes is the minimum size of IPv4 datagram every device must be able to forward without further fragmentation while 576 bytes is the minimum size of IPv4 datagram every device has to be able to receive, so in ip6_tnl_xmit(), 68(IPV4_MIN_MTU) should be the right value for the ipv4 min mtu check in ip6_tnl_xmit. While at it, change to use max() instead of if statement. Fixes: c9fefa08190f ("ip6_tunnel: get the min mtu properly in ip6_tnl_xmit") Reported-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv6/ip6_tunnel.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 00e138a44cbb..1cc9650af9fb 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1133,12 +1133,8 @@ route_lookup:
max_headroom += 8;
mtu -= 8;
}
- if (skb->protocol == htons(ETH_P_IPV6)) {
- if (mtu < IPV6_MIN_MTU)
- mtu = IPV6_MIN_MTU;
- } else if (mtu < 576) {
- mtu = 576;
- }
+ mtu = max(mtu, skb->protocol == htons(ETH_P_IPV6) ?
+ IPV6_MIN_MTU : IPV4_MIN_MTU);
skb_dst_update_pmtu(skb, mtu);
if (skb->len - t->tun_hlen - eth_hlen > mtu && !skb_is_gso(skb)) {