From ee34c1eb35923cc98b1c47488a615bf51a2a2afb Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Thu, 13 Dec 2007 09:46:32 -0800 Subject: [PATCH] [IP_GRE]: Rebinding of GRE tunnels to other interfaces This is similar to the change already done for IPIP tunnels. Once created, a GRE tunnel can't be bound to another device. To reproduce: # create a tunnel: ip tunnel add tunneltest0 mode gre 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: gre/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. Signed-off-by: Michal Schmidt Signed-off-by: David S. Miller --- net/ipv4/ip_gre.c | 102 +++++++++++++++++++++++++++------------------- 1 file changed, 60 insertions(+), 42 deletions(-) diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 4b93f32de10d..0832f6e028b8 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -896,6 +896,59 @@ tx_error: return 0; } +static void ipgre_tunnel_bind_dev(struct net_device *dev) +{ + struct net_device *tdev = NULL; + struct ip_tunnel *tunnel; + struct iphdr *iph; + int hlen = LL_MAX_HEADER; + int mtu = ETH_DATA_LEN; + int addend = sizeof(struct iphdr) + 4; + + tunnel = netdev_priv(dev); + iph = &tunnel->parms.iph; + + /* Guess output device to choose reasonable mtu and hard_header_len */ + + 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_GRE }; + 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) { + hlen = tdev->hard_header_len; + mtu = tdev->mtu; + } + dev->iflink = tunnel->parms.link; + + /* Precalculate GRE options length */ + if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) { + if (tunnel->parms.o_flags&GRE_CSUM) + addend += 4; + if (tunnel->parms.o_flags&GRE_KEY) + addend += 4; + if (tunnel->parms.o_flags&GRE_SEQ) + addend += 4; + } + dev->hard_header_len = hlen + addend; + dev->mtu = mtu - addend; + tunnel->hlen = addend; + +} + static int ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) { @@ -983,6 +1036,11 @@ ipgre_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; + ipgre_tunnel_bind_dev(dev); + netdev_state_change(dev); + } } if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p))) err = -EFAULT; @@ -1162,12 +1220,8 @@ static void ipgre_tunnel_setup(struct net_device *dev) static int ipgre_tunnel_init(struct net_device *dev) { - struct net_device *tdev = NULL; struct ip_tunnel *tunnel; struct iphdr *iph; - int hlen = LL_MAX_HEADER; - int mtu = ETH_DATA_LEN; - int addend = sizeof(struct iphdr) + 4; tunnel = netdev_priv(dev); iph = &tunnel->parms.iph; @@ -1178,23 +1232,9 @@ static int ipgre_tunnel_init(struct net_device *dev) memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4); memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4); - /* Guess output device to choose reasonable mtu and hard_header_len */ + ipgre_tunnel_bind_dev(dev); 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_GRE }; - struct rtable *rt; - if (!ip_route_output_key(&rt, &fl)) { - tdev = rt->u.dst.dev; - ip_rt_put(rt); - } - - dev->flags |= IFF_POINTOPOINT; - #ifdef CONFIG_NET_IPGRE_BROADCAST if (MULTICAST(iph->daddr)) { if (!iph->saddr) @@ -1205,31 +1245,9 @@ static int ipgre_tunnel_init(struct net_device *dev) dev->stop = ipgre_close; } #endif - } else { + } else dev->header_ops = &ipgre_header_ops; - } - - if (!tdev && tunnel->parms.link) - tdev = __dev_get_by_index(&init_net, tunnel->parms.link); - - if (tdev) { - hlen = tdev->hard_header_len; - mtu = tdev->mtu; - } - dev->iflink = tunnel->parms.link; - /* Precalculate GRE options length */ - if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) { - if (tunnel->parms.o_flags&GRE_CSUM) - addend += 4; - if (tunnel->parms.o_flags&GRE_KEY) - addend += 4; - if (tunnel->parms.o_flags&GRE_SEQ) - addend += 4; - } - dev->hard_header_len = hlen + addend; - dev->mtu = mtu - addend; - tunnel->hlen = addend; return 0; } -- 2.30.2