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Commit 8a118015 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'tunnel-mtus' 



Nicolas Dichtel says:

====================
ip[6] tunnels: fix mtu calculations

The first patch restores the possibility to bind an ip4 tunnel to an
interface whith a large mtu.
The second patch was spotted after the first fix. I also target it to net
because it fixes the max mtu value that can be used for ipv6 tunnels.

v2: remove the 0xfff8 in ip_tunnel_newlink()
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents ccfde6e2 f7ff1fde

net/ipv4/ip_tunnel.c

+4 −4
Original line number Original line Diff line number Diff line
@@ -328,7 +328,7 @@ static int ip_tunnel_bind_dev(struct net_device *dev) 




	if (tdev) {

	if (tdev) {

		hlen = tdev->hard_header_len + tdev->needed_headroom;

		hlen = tdev->hard_header_len + tdev->needed_headroom;

		mtu = tdev->mtu;

		mtu = min(tdev->mtu, IP_MAX_MTU);

	}

	}





	dev->needed_headroom = t_hlen + hlen;

	dev->needed_headroom = t_hlen + hlen;
@@ -362,7 +362,7 @@ static struct ip_tunnel *ip_tunnel_create(struct net *net, 
	nt = netdev_priv(dev);

	nt = netdev_priv(dev);

	t_hlen = nt->hlen + sizeof(struct iphdr);

	t_hlen = nt->hlen + sizeof(struct iphdr);

	dev->min_mtu = ETH_MIN_MTU;

	dev->min_mtu = ETH_MIN_MTU;

	dev->max_mtu = 0xFFF8 - dev->hard_header_len - t_hlen;

	dev->max_mtu = IP_MAX_MTU - dev->hard_header_len - t_hlen;

	ip_tunnel_add(itn, nt);

	ip_tunnel_add(itn, nt);

	return nt;

	return nt;
@@ -930,7 +930,7 @@ int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict) 
{

{

	struct ip_tunnel *tunnel = netdev_priv(dev);

	struct ip_tunnel *tunnel = netdev_priv(dev);

	int t_hlen = tunnel->hlen + sizeof(struct iphdr);

	int t_hlen = tunnel->hlen + sizeof(struct iphdr);

	int max_mtu = 0xFFF8 - dev->hard_header_len - t_hlen;

	int max_mtu = IP_MAX_MTU - dev->hard_header_len - t_hlen;





	if (new_mtu < ETH_MIN_MTU)

	if (new_mtu < ETH_MIN_MTU)

		return -EINVAL;

		return -EINVAL;
@@ -1107,7 +1107,7 @@ int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[], 




	mtu = ip_tunnel_bind_dev(dev);

	mtu = ip_tunnel_bind_dev(dev);

	if (tb[IFLA_MTU]) {

	if (tb[IFLA_MTU]) {

		unsigned int max = 0xfff8 - dev->hard_header_len - nt->hlen;

		unsigned int max = IP_MAX_MTU - dev->hard_header_len - nt->hlen;





		mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU,

		mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU,

			    (unsigned int)(max - sizeof(struct iphdr)));

			    (unsigned int)(max - sizeof(struct iphdr)));

net/ipv6/ip6_tunnel.c

+8 −3
Original line number Original line Diff line number Diff line
@@ -1692,8 +1692,13 @@ int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu) 
		if (new_mtu < ETH_MIN_MTU)

		if (new_mtu < ETH_MIN_MTU)

			return -EINVAL;

			return -EINVAL;

	}

	}

	if (new_mtu > 0xFFF8 - dev->hard_header_len)

	if (tnl->parms.proto == IPPROTO_IPV6 || tnl->parms.proto == 0) {

		if (new_mtu > IP6_MAX_MTU - dev->hard_header_len)

			return -EINVAL;

			return -EINVAL;

	} else {

		if (new_mtu > IP_MAX_MTU - dev->hard_header_len)

			return -EINVAL;

	}

	dev->mtu = new_mtu;

	dev->mtu = new_mtu;

	return 0;

	return 0;

}

}
@@ -1841,7 +1846,7 @@ ip6_tnl_dev_init_gen(struct net_device *dev) 
	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))

	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))

		dev->mtu -= 8;

		dev->mtu -= 8;

	dev->min_mtu = ETH_MIN_MTU;

	dev->min_mtu = ETH_MIN_MTU;

	dev->max_mtu = 0xFFF8 - dev->hard_header_len;

	dev->max_mtu = IP6_MAX_MTU - dev->hard_header_len;





	return 0;

	return 0;

net/ipv6/sit.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -1371,7 +1371,7 @@ static void ipip6_tunnel_setup(struct net_device *dev) 
	dev->hard_header_len	= LL_MAX_HEADER + t_hlen;

	dev->hard_header_len	= LL_MAX_HEADER + t_hlen;

	dev->mtu		= ETH_DATA_LEN - t_hlen;

	dev->mtu		= ETH_DATA_LEN - t_hlen;

	dev->min_mtu		= IPV6_MIN_MTU;

	dev->min_mtu		= IPV6_MIN_MTU;

	dev->max_mtu		= 0xFFF8 - t_hlen;

	dev->max_mtu		= IP6_MAX_MTU - t_hlen;

	dev->flags		= IFF_NOARP;

	dev->flags		= IFF_NOARP;

	netif_keep_dst(dev);

	netif_keep_dst(dev);

	dev->addr_len		= 4;

	dev->addr_len		= 4;
@@ -1583,7 +1583,8 @@ static int ipip6_newlink(struct net *src_net, struct net_device *dev, 
	if (tb[IFLA_MTU]) {

	if (tb[IFLA_MTU]) {

		u32 mtu = nla_get_u32(tb[IFLA_MTU]);

		u32 mtu = nla_get_u32(tb[IFLA_MTU]);





		if (mtu >= IPV6_MIN_MTU && mtu <= 0xFFF8 - dev->hard_header_len)

		if (mtu >= IPV6_MIN_MTU &&

		    mtu <= IP6_MAX_MTU - dev->hard_header_len)

			dev->mtu = mtu;

			dev->mtu = mtu;

	}

	}