1 files 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;
 }