ip6_tunnel: use the right value for ipv4 min mtu check in ip6_tnl_xmit
[ Upstream commitpull/10/head82a40777de
] 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:c9fefa0819
("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parent
59f9f2c76f
commit
b3fb939872
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@ -1134,12 +1134,8 @@ route_lookup:
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max_headroom += 8;
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mtu -= 8;
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}
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if (skb->protocol == htons(ETH_P_IPV6)) {
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if (mtu < IPV6_MIN_MTU)
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mtu = IPV6_MIN_MTU;
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} else if (mtu < 576) {
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mtu = 576;
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}
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mtu = max(mtu, skb->protocol == htons(ETH_P_IPV6) ?
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IPV6_MIN_MTU : IPV4_MIN_MTU);
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skb_dst_update_pmtu(skb, mtu);
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if (skb->len - t->tun_hlen - eth_hlen > mtu && !skb_is_gso(skb)) {
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