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authorStefano Brivio <sbrivio@redhat.com>2018-03-15 17:17:13 +0100
committerSteffen Klassert <steffen.klassert@secunet.com>2018-03-19 08:45:50 +0100
commitf8a554b4aa9686bb2c12f6bae516e58783289a03 (patch)
tree62c9d02997f5bd64d8868dc4c754eef7eaa2a84e /net/ipv6/ip6_vti.c
parentvti6: Keep set MTU on link creation or change, validate it (diff)
downloadlinux-dev-f8a554b4aa9686bb2c12f6bae516e58783289a03.tar.xz
linux-dev-f8a554b4aa9686bb2c12f6bae516e58783289a03.zip
vti6: Fix dev->max_mtu setting
We shouldn't allow a tunnel to have IP_MAX_MTU as MTU, because another IPv6 header is going on top of our packets. Without this patch, we might end up building packets bigger than IP_MAX_MTU. Fixes: b96f9afee4eb ("ipv4/6: use core net MTU range checking") Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Acked-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/ipv6/ip6_vti.c')
-rw-r--r--net/ipv6/ip6_vti.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 971175142e14..ce18cd20389d 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -879,7 +879,7 @@ static void vti6_dev_setup(struct net_device *dev)
dev->type = ARPHRD_TUNNEL6;
dev->min_mtu = IPV6_MIN_MTU;
- dev->max_mtu = IP_MAX_MTU;
+ dev->max_mtu = IP_MAX_MTU - sizeof(struct ipv6hdr);
dev->flags |= IFF_NOARP;
dev->addr_len = sizeof(struct in6_addr);
netif_keep_dst(dev);