Commit 1b227e53 authored May 21, 2016 by Haishuang Yan Committed by David S. Miller May 24, 2016

ip6_gre: Fix MTU setting for ip6gretap



When creat an ip6gretap interface with an unreachable route,
the MTU is about 14 bytes larger than what was needed.

If the remote address is reachable:
ping6 2001:0:130::1 -c 2
PING 2001:0:130::1(2001:0:130::1) 56 data bytes
64 bytes from 2001:0:130::1: icmp_seq=1 ttl=64 time=1.46 ms
64 bytes from 2001:0:130::1: icmp_seq=2 ttl=64 time=81.1 ms

Signed-off-by: David S. Miller <davem@davemloft.net>

parent 54b9430f

net/ipv6/ip6_gre.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1027,6 +1027,8 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)

		dev->hard_header_len = LL_MAX_HEADER + t_hlen;
		dev->mtu = ETH_DATA_LEN - t_hlen;
		if (dev->type == ARPHRD_ETHER)
		dev->mtu -= ETH_HLEN;
		if (!(tunnel->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
		dev->mtu -= 8;

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