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: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 6b0e362cc99b5d3510ea7aa8db68dcb5c8eb675c..38d906baf1df837c5009b7487fb14f6a1c11acaa 100644 (file)
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -328,7 +328,7 @@ static int ip_tunnel_bind_dev(struct net_device *dev)
 
        if (tdev) {
                hlen = tdev->hard_header_len + tdev->needed_headroom;
-               mtu = tdev->mtu;
+               mtu = min(tdev->mtu, IP_MAX_MTU);
        }
 
        dev->needed_headroom = t_hlen + hlen;
@@ -362,7 +362,7 @@ static struct ip_tunnel *ip_tunnel_create(struct net *net,
        nt = netdev_priv(dev);
        t_hlen = nt->hlen + sizeof(struct iphdr);
        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);
        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);
        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)
                return -EINVAL;
@@ -1107,7 +1107,7 @@ int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
 
        mtu = ip_tunnel_bind_dev(dev);
        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,
                            (unsigned int)(max - sizeof(struct iphdr)));

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index da66aaac51cecbf933827c8842e61a8cbb4d274f..00e138a44cbba2e7c03cb003f5823b42e18a923a 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1692,8 +1692,13 @@ int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
                if (new_mtu < ETH_MIN_MTU)
                        return -EINVAL;
        }
-       if (new_mtu > 0xFFF8 - dev->hard_header_len)
-               return -EINVAL;
+       if (tnl->parms.proto == IPPROTO_IPV6 || tnl->parms.proto == 0) {
+               if (new_mtu > IP6_MAX_MTU - dev->hard_header_len)
+                       return -EINVAL;
+       } else {
+               if (new_mtu > IP_MAX_MTU - dev->hard_header_len)
+                       return -EINVAL;
+       }
        dev->mtu = new_mtu;
        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))
                dev->mtu -= 8;
        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;
 

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 2afce37a71776f5ebd44d20e2d064909cb91f8dd..e9400ffa7875c7a81d139618dae53143d164a1e1 100644 (file)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1371,7 +1371,7 @@ static void ipip6_tunnel_setup(struct net_device *dev)
        dev->hard_header_len    = LL_MAX_HEADER + t_hlen;
        dev->mtu                = ETH_DATA_LEN - t_hlen;
        dev->min_mtu            = IPV6_MIN_MTU;
-       dev->max_mtu            = 0xFFF8 - t_hlen;
+       dev->max_mtu            = IP6_MAX_MTU - t_hlen;
        dev->flags              = IFF_NOARP;
        netif_keep_dst(dev);
        dev->addr_len           = 4;
@@ -1583,7 +1583,8 @@ static int ipip6_newlink(struct net *src_net, struct net_device *dev,
        if (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;
        }