Commit b4331a68 authored Apr 26, 2018 by Stefano Brivio Committed by Steffen Klassert Apr 27, 2018

vti6: Change minimum MTU to IPV4_MIN_MTU, vti6 can carry IPv4 too



A vti6 interface can carry IPv4 as well, so it makes no sense to
enforce a minimum MTU of IPV6_MIN_MTU.

If the user sets an MTU below IPV6_MIN_MTU, IPv6 will be
disabled on the interface, courtesy of addrconf_notify().

Reported-by: Xin Long <lucien.xin@gmail.com>
Fixes: b96f9afe ("ipv4/6: use core net MTU range checking")
Fixes: c6741fbe ("vti6: Properly adjust vti6 MTU from MTU of lower device")
Fixes: 53c81e95 ("ip6_vti: adjust vti mtu according to mtu of lower device")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

parent b48c05ab

net/ipv6/ip6_vti.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -669,7 +669,7 @@ static void vti6_link_config(struct ip6_tnl *t, bool keep_mtu)
		else
		mtu = ETH_DATA_LEN - LL_MAX_HEADER - sizeof(struct ipv6hdr);

		dev->mtu = max_t(int, mtu, IPV6_MIN_MTU);
		dev->mtu = max_t(int, mtu, IPV4_MIN_MTU);
		}

		/**
		@@ -881,7 +881,7 @@ static void vti6_dev_setup(struct net_device *dev)
		dev->priv_destructor = vti6_dev_free;

		dev->type = ARPHRD_TUNNEL6;
		dev->min_mtu = IPV6_MIN_MTU;
		dev->min_mtu = IPV4_MIN_MTU;
		dev->max_mtu = IP_MAX_MTU - sizeof(struct ipv6hdr);
		dev->flags \|= IFF_NOARP;
		dev->addr_len = sizeof(struct in6_addr);

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