From 5533995b62d02dbbf930f2e59221c2d5ea05aab7 Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Wed, 12 Dec 2007 11:01:43 -0800 Subject: [PATCH] [IPIP]: Allow rebinding the tunnel to another interface Once created, an IP tunnel can't be bound to another device. (reported as https://bugzilla.redhat.com/show_bug.cgi?id=419671) To reproduce: # create a tunnel: ip tunnel add tunneltest0 mode ipip remote 10.0.0.1 dev eth0 # try to change the bounding device from eth0 to eth1: ip tunnel change tunneltest0 dev eth1 # show the result: ip tunnel show tunneltest0 tunneltest0: ip/ip remote 10.0.0.1 local any dev eth0 ttl inherit Notice the bound device has not changed from eth0 to eth1. This patch fixes it. When changing the binding, it also recalculates the MTU according to the new bound device's MTU. If the change is acceptable, I'll do the same for GRE and SIT tunnels. Signed-off-by: Michal Schmidt Signed-off-by: David S. Miller --- net/ipv4/ipip.c | 66 ++++++++++++++++++++++++++++++------------------- 1 file changed, 40 insertions(+), 26 deletions(-) diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c index 8c2b2b0741da..160535b51705 100644 --- a/net/ipv4/ipip.c +++ b/net/ipv4/ipip.c @@ -651,6 +651,40 @@ tx_error: return 0; } +static void ipip_tunnel_bind_dev(struct net_device *dev) +{ + struct net_device *tdev = NULL; + struct ip_tunnel *tunnel; + struct iphdr *iph; + + tunnel = netdev_priv(dev); + iph = &tunnel->parms.iph; + + if (iph->daddr) { + struct flowi fl = { .oif = tunnel->parms.link, + .nl_u = { .ip4_u = + { .daddr = iph->daddr, + .saddr = iph->saddr, + .tos = RT_TOS(iph->tos) } }, + .proto = IPPROTO_IPIP }; + struct rtable *rt; + if (!ip_route_output_key(&rt, &fl)) { + tdev = rt->u.dst.dev; + ip_rt_put(rt); + } + dev->flags |= IFF_POINTOPOINT; + } + + if (!tdev && tunnel->parms.link) + tdev = __dev_get_by_index(&init_net, tunnel->parms.link); + + if (tdev) { + dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr); + dev->mtu = tdev->mtu - sizeof(struct iphdr); + } + dev->iflink = tunnel->parms.link; +} + static int ipip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) { @@ -723,6 +757,11 @@ ipip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) t->parms.iph.ttl = p.iph.ttl; t->parms.iph.tos = p.iph.tos; t->parms.iph.frag_off = p.iph.frag_off; + if (t->parms.link != p.link) { + t->parms.link = p.link; + ipip_tunnel_bind_dev(dev); + netdev_state_change(dev); + } } if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p))) err = -EFAULT; @@ -791,12 +830,9 @@ static void ipip_tunnel_setup(struct net_device *dev) static int ipip_tunnel_init(struct net_device *dev) { - struct net_device *tdev = NULL; struct ip_tunnel *tunnel; - struct iphdr *iph; tunnel = netdev_priv(dev); - iph = &tunnel->parms.iph; tunnel->dev = dev; strcpy(tunnel->parms.name, dev->name); @@ -804,29 +840,7 @@ static int ipip_tunnel_init(struct net_device *dev) memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4); memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4); - if (iph->daddr) { - struct flowi fl = { .oif = tunnel->parms.link, - .nl_u = { .ip4_u = - { .daddr = iph->daddr, - .saddr = iph->saddr, - .tos = RT_TOS(iph->tos) } }, - .proto = IPPROTO_IPIP }; - struct rtable *rt; - if (!ip_route_output_key(&rt, &fl)) { - tdev = rt->u.dst.dev; - ip_rt_put(rt); - } - dev->flags |= IFF_POINTOPOINT; - } - - if (!tdev && tunnel->parms.link) - tdev = __dev_get_by_index(&init_net, tunnel->parms.link); - - if (tdev) { - dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr); - dev->mtu = tdev->mtu - sizeof(struct iphdr); - } - dev->iflink = tunnel->parms.link; + ipip_tunnel_bind_dev(dev); return 0; } -- 2.20.1