net/ipv4: VTI support new module for ip_vti.
authorSaurabh <saurabh.mohan@vyatta.com>
Tue, 17 Jul 2012 09:44:54 +0000 (09:44 +0000)
committerDavid S. Miller <davem@davemloft.net>
Wed, 18 Jul 2012 16:36:12 +0000 (09:36 -0700)
New VTI tunnel kernel module, Kconfig and Makefile changes.

Signed-off-by: Saurabh Mohan <saurabh.mohan@vyatta.com>
Reviewed-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/linux/if_tunnel.h
net/ipv4/Kconfig
net/ipv4/Makefile
net/ipv4/ip_vti.c [new file with mode: 0644]

index 16b92d008bed842e141f77664e94446cbe652dcf..5efff60b6f56906112b5c71dffbdf47b2b22cc8d 100644 (file)
@@ -80,4 +80,18 @@ enum {
 
 #define IFLA_GRE_MAX   (__IFLA_GRE_MAX - 1)
 
+/* VTI-mode i_flags */
+#define VTI_ISVTI 0x0001
+
+enum {
+       IFLA_VTI_UNSPEC,
+       IFLA_VTI_LINK,
+       IFLA_VTI_IKEY,
+       IFLA_VTI_OKEY,
+       IFLA_VTI_LOCAL,
+       IFLA_VTI_REMOTE,
+       __IFLA_VTI_MAX,
+};
+
+#define IFLA_VTI_MAX   (__IFLA_VTI_MAX - 1)
 #endif /* _IF_TUNNEL_H_ */
index 20f1cb5c8aba6b7eb2efeb3c579e998a5eac6419..5a19aeb8609432f24e76291db7ebb3526642b259 100644 (file)
@@ -310,6 +310,17 @@ config SYN_COOKIES
 
          If unsure, say N.
 
+config NET_IPVTI
+       tristate "Virtual (secure) IP: tunneling"
+       select INET_TUNNEL
+       depends on INET_XFRM_MODE_TUNNEL
+       ---help---
+         Tunneling means encapsulating data of one protocol type within
+         another protocol and sending it over a channel that understands the
+         encapsulating protocol. This can be used with xfrm mode tunnel to give
+         the notion of a secure tunnel for IPSEC and then use routing protocol
+         on top.
+
 config INET_AH
        tristate "IP: AH transformation"
        select XFRM_ALGO
index 5a23e8b371061e2d597631a464bb33a65e2ee969..a677d804e53ef17d9a0114cad1bbdf601951f9a9 100644 (file)
@@ -20,6 +20,7 @@ obj-$(CONFIG_IP_MROUTE) += ipmr.o
 obj-$(CONFIG_NET_IPIP) += ipip.o
 obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o
 obj-$(CONFIG_NET_IPGRE) += ip_gre.o
+obj-$(CONFIG_NET_IPVTI) += ip_vti.o
 obj-$(CONFIG_SYN_COOKIES) += syncookies.o
 obj-$(CONFIG_INET_AH) += ah4.o
 obj-$(CONFIG_INET_ESP) += esp4.o
diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
new file mode 100644 (file)
index 0000000..c41b5c3
--- /dev/null
@@ -0,0 +1,956 @@
+/*
+ *     Linux NET3: IP/IP protocol decoder modified to support
+ *                 virtual tunnel interface
+ *
+ *     Authors:
+ *             Saurabh Mohan (saurabh.mohan@vyatta.com) 05/07/2012
+ *
+ *     This program is free software; you can redistribute it and/or
+ *     modify it under the terms of the GNU General Public License
+ *     as published by the Free Software Foundation; either version
+ *     2 of the License, or (at your option) any later version.
+ *
+ */
+
+/*
+   This version of net/ipv4/ip_vti.c is cloned of net/ipv4/ipip.c
+
+   For comments look at net/ipv4/ip_gre.c --ANK
+ */
+
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/uaccess.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/in.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/if_arp.h>
+#include <linux/mroute.h>
+#include <linux/init.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/if_ether.h>
+
+#include <net/sock.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/ipip.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+#define HASH_SIZE  16
+#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&(HASH_SIZE-1))
+
+static struct rtnl_link_ops vti_link_ops __read_mostly;
+
+static int vti_net_id __read_mostly;
+struct vti_net {
+       struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
+       struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
+       struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
+       struct ip_tunnel __rcu *tunnels_wc[1];
+       struct ip_tunnel **tunnels[4];
+
+       struct net_device *fb_tunnel_dev;
+};
+
+static int vti_fb_tunnel_init(struct net_device *dev);
+static int vti_tunnel_init(struct net_device *dev);
+static void vti_tunnel_setup(struct net_device *dev);
+static void vti_dev_free(struct net_device *dev);
+static int vti_tunnel_bind_dev(struct net_device *dev);
+
+/* Locking : hash tables are protected by RCU and RTNL */
+
+#define for_each_ip_tunnel_rcu(start) \
+       for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
+
+/* often modified stats are per cpu, other are shared (netdev->stats) */
+struct pcpu_tstats {
+       u64     rx_packets;
+       u64     rx_bytes;
+       u64     tx_packets;
+       u64     tx_bytes;
+       struct  u64_stats_sync  syncp;
+};
+
+#define VTI_XMIT(stats1, stats2) do {                          \
+       int err;                                                \
+       int pkt_len = skb->len;                                 \
+       err = dst_output(skb);                                  \
+       if (net_xmit_eval(err) == 0) {                          \
+               u64_stats_update_begin(&(stats1)->syncp);       \
+               (stats1)->tx_bytes += pkt_len;                  \
+               (stats1)->tx_packets++;                         \
+               u64_stats_update_end(&(stats1)->syncp);         \
+       } else {                                                \
+               (stats2)->tx_errors++;                          \
+               (stats2)->tx_aborted_errors++;                  \
+       }                                                       \
+} while (0)
+
+
+static struct rtnl_link_stats64 *vti_get_stats64(struct net_device *dev,
+                                                struct rtnl_link_stats64 *tot)
+{
+       int i;
+
+       for_each_possible_cpu(i) {
+               const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
+               u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
+               unsigned int start;
+
+               do {
+                       start = u64_stats_fetch_begin_bh(&tstats->syncp);
+                       rx_packets = tstats->rx_packets;
+                       tx_packets = tstats->tx_packets;
+                       rx_bytes = tstats->rx_bytes;
+                       tx_bytes = tstats->tx_bytes;
+               } while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
+
+               tot->rx_packets += rx_packets;
+               tot->tx_packets += tx_packets;
+               tot->rx_bytes   += rx_bytes;
+               tot->tx_bytes   += tx_bytes;
+       }
+
+       tot->multicast = dev->stats.multicast;
+       tot->rx_crc_errors = dev->stats.rx_crc_errors;
+       tot->rx_fifo_errors = dev->stats.rx_fifo_errors;
+       tot->rx_length_errors = dev->stats.rx_length_errors;
+       tot->rx_errors = dev->stats.rx_errors;
+       tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
+       tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
+       tot->tx_dropped = dev->stats.tx_dropped;
+       tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
+       tot->tx_errors = dev->stats.tx_errors;
+
+       return tot;
+}
+
+static struct ip_tunnel *vti_tunnel_lookup(struct net *net,
+                                          __be32 remote, __be32 local)
+{
+       unsigned h0 = HASH(remote);
+       unsigned h1 = HASH(local);
+       struct ip_tunnel *t;
+       struct vti_net *ipn = net_generic(net, vti_net_id);
+
+       for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
+               if (local == t->parms.iph.saddr &&
+                   remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
+                       return t;
+       for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
+               if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
+                       return t;
+
+       for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
+               if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
+                       return t;
+
+       for_each_ip_tunnel_rcu(ipn->tunnels_wc[0])
+               if (t && (t->dev->flags&IFF_UP))
+                       return t;
+       return NULL;
+}
+
+static struct ip_tunnel **__vti_bucket(struct vti_net *ipn,
+                                      struct ip_tunnel_parm *parms)
+{
+       __be32 remote = parms->iph.daddr;
+       __be32 local = parms->iph.saddr;
+       unsigned h = 0;
+       int prio = 0;
+
+       if (remote) {
+               prio |= 2;
+               h ^= HASH(remote);
+       }
+       if (local) {
+               prio |= 1;
+               h ^= HASH(local);
+       }
+       return &ipn->tunnels[prio][h];
+}
+
+static inline struct ip_tunnel **vti_bucket(struct vti_net *ipn,
+                                           struct ip_tunnel *t)
+{
+       return __vti_bucket(ipn, &t->parms);
+}
+
+static void vti_tunnel_unlink(struct vti_net *ipn, struct ip_tunnel *t)
+{
+       struct ip_tunnel __rcu **tp;
+       struct ip_tunnel *iter;
+
+       for (tp = vti_bucket(ipn, t);
+            (iter = rtnl_dereference(*tp)) != NULL;
+            tp = &iter->next) {
+               if (t == iter) {
+                       rcu_assign_pointer(*tp, t->next);
+                       break;
+               }
+       }
+}
+
+static void vti_tunnel_link(struct vti_net *ipn, struct ip_tunnel *t)
+{
+       struct ip_tunnel __rcu **tp = vti_bucket(ipn, t);
+
+       rcu_assign_pointer(t->next, rtnl_dereference(*tp));
+       rcu_assign_pointer(*tp, t);
+}
+
+static struct ip_tunnel *vti_tunnel_locate(struct net *net,
+                                          struct ip_tunnel_parm *parms,
+                                          int create)
+{
+       __be32 remote = parms->iph.daddr;
+       __be32 local = parms->iph.saddr;
+       struct ip_tunnel *t, *nt;
+       struct ip_tunnel __rcu **tp;
+       struct net_device *dev;
+       char name[IFNAMSIZ];
+       struct vti_net *ipn = net_generic(net, vti_net_id);
+
+       for (tp = __vti_bucket(ipn, parms);
+            (t = rtnl_dereference(*tp)) != NULL;
+            tp = &t->next) {
+               if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
+                       return t;
+       }
+       if (!create)
+               return NULL;
+
+       if (parms->name[0])
+               strlcpy(name, parms->name, IFNAMSIZ);
+       else
+               strcpy(name, "vti%d");
+
+       dev = alloc_netdev(sizeof(*t), name, vti_tunnel_setup);
+       if (dev == NULL)
+               return NULL;
+
+       dev_net_set(dev, net);
+
+       nt = netdev_priv(dev);
+       nt->parms = *parms;
+       dev->rtnl_link_ops = &vti_link_ops;
+
+       vti_tunnel_bind_dev(dev);
+
+       if (register_netdevice(dev) < 0)
+               goto failed_free;
+
+       dev_hold(dev);
+       vti_tunnel_link(ipn, nt);
+       return nt;
+
+failed_free:
+       free_netdev(dev);
+       return NULL;
+}
+
+static void vti_tunnel_uninit(struct net_device *dev)
+{
+       struct net *net = dev_net(dev);
+       struct vti_net *ipn = net_generic(net, vti_net_id);
+
+       vti_tunnel_unlink(ipn, netdev_priv(dev));
+       dev_put(dev);
+}
+
+static int vti_err(struct sk_buff *skb, u32 info)
+{
+
+       /* All the routers (except for Linux) return only
+        * 8 bytes of packet payload. It means, that precise relaying of
+        * ICMP in the real Internet is absolutely infeasible.
+        */
+       struct iphdr *iph = (struct iphdr *)skb->data;
+       const int type = icmp_hdr(skb)->type;
+       const int code = icmp_hdr(skb)->code;
+       struct ip_tunnel *t;
+       int err;
+
+       switch (type) {
+       default:
+       case ICMP_PARAMETERPROB:
+               return 0;
+
+       case ICMP_DEST_UNREACH:
+               switch (code) {
+               case ICMP_SR_FAILED:
+               case ICMP_PORT_UNREACH:
+                       /* Impossible event. */
+                       return 0;
+               default:
+                       /* All others are translated to HOST_UNREACH. */
+                       break;
+               }
+               break;
+       case ICMP_TIME_EXCEEDED:
+               if (code != ICMP_EXC_TTL)
+                       return 0;
+               break;
+       }
+
+       err = -ENOENT;
+
+       rcu_read_lock();
+       t = vti_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
+       if (t == NULL)
+               goto out;
+
+       if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
+               ipv4_update_pmtu(skb, dev_net(skb->dev), info,
+                                t->parms.link, 0, IPPROTO_IPIP, 0);
+               err = 0;
+               goto out;
+       }
+
+       err = 0;
+       if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
+               goto out;
+
+       if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
+               t->err_count++;
+       else
+               t->err_count = 1;
+       t->err_time = jiffies;
+out:
+       rcu_read_unlock();
+       return err;
+}
+
+/* We dont digest the packet therefore let the packet pass */
+static int vti_rcv(struct sk_buff *skb)
+{
+       struct ip_tunnel *tunnel;
+       const struct iphdr *iph = ip_hdr(skb);
+
+       rcu_read_lock();
+       tunnel = vti_tunnel_lookup(dev_net(skb->dev), iph->saddr, iph->daddr);
+       if (tunnel != NULL) {
+               struct pcpu_tstats *tstats;
+
+               tstats = this_cpu_ptr(tunnel->dev->tstats);
+               u64_stats_update_begin(&tstats->syncp);
+               tstats->rx_packets++;
+               tstats->rx_bytes += skb->len;
+               u64_stats_update_end(&tstats->syncp);
+
+               skb->dev = tunnel->dev;
+               rcu_read_unlock();
+               return 1;
+       }
+       rcu_read_unlock();
+
+       return -1;
+}
+
+/* This function assumes it is being called from dev_queue_xmit()
+ * and that skb is filled properly by that function.
+ */
+
+static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+       struct ip_tunnel *tunnel = netdev_priv(dev);
+       struct pcpu_tstats *tstats;
+       struct iphdr  *tiph = &tunnel->parms.iph;
+       u8     tos;
+       struct rtable *rt;              /* Route to the other host */
+       struct net_device *tdev;        /* Device to other host */
+       struct iphdr  *old_iph = ip_hdr(skb);
+       __be32 dst = tiph->daddr;
+       struct flowi4 fl4;
+
+       if (skb->protocol != htons(ETH_P_IP))
+               goto tx_error;
+
+       tos = old_iph->tos;
+
+       memset(&fl4, 0, sizeof(fl4));
+       flowi4_init_output(&fl4, tunnel->parms.link,
+                          htonl(tunnel->parms.i_key), RT_TOS(tos),
+                          RT_SCOPE_UNIVERSE,
+                          IPPROTO_IPIP, 0,
+                          dst, tiph->saddr, 0, 0);
+       rt = ip_route_output_key(dev_net(dev), &fl4);
+       if (IS_ERR(rt)) {
+               dev->stats.tx_carrier_errors++;
+               goto tx_error_icmp;
+       }
+       /* if there is no transform then this tunnel is not functional.
+        * Or if the xfrm is not mode tunnel.
+        */
+       if (!rt->dst.xfrm ||
+           rt->dst.xfrm->props.mode != XFRM_MODE_TUNNEL) {
+               dev->stats.tx_carrier_errors++;
+               goto tx_error_icmp;
+       }
+       tdev = rt->dst.dev;
+
+       if (tdev == dev) {
+               ip_rt_put(rt);
+               dev->stats.collisions++;
+               goto tx_error;
+       }
+
+       if (tunnel->err_count > 0) {
+               if (time_before(jiffies,
+                               tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
+                       tunnel->err_count--;
+                       dst_link_failure(skb);
+               } else
+                       tunnel->err_count = 0;
+       }
+
+       IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
+                             IPSKB_REROUTED);
+       skb_dst_drop(skb);
+       skb_dst_set(skb, &rt->dst);
+       nf_reset(skb);
+       skb->dev = skb_dst(skb)->dev;
+
+       tstats = this_cpu_ptr(dev->tstats);
+       VTI_XMIT(tstats, &dev->stats);
+       return NETDEV_TX_OK;
+
+tx_error_icmp:
+       dst_link_failure(skb);
+tx_error:
+       dev->stats.tx_errors++;
+       dev_kfree_skb(skb);
+       return NETDEV_TX_OK;
+}
+
+static int vti_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 rtable *rt;
+               struct flowi4 fl4;
+               memset(&fl4, 0, sizeof(fl4));
+               flowi4_init_output(&fl4, tunnel->parms.link,
+                                  htonl(tunnel->parms.i_key),
+                                  RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
+                                  IPPROTO_IPIP, 0,
+                                  iph->daddr, iph->saddr, 0, 0);
+               rt = ip_route_output_key(dev_net(dev), &fl4);
+               if (!IS_ERR(rt)) {
+                       tdev = rt->dst.dev;
+                       ip_rt_put(rt);
+               }
+               dev->flags |= IFF_POINTOPOINT;
+       }
+
+       if (!tdev && tunnel->parms.link)
+               tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
+
+       if (tdev) {
+               dev->hard_header_len = tdev->hard_header_len +
+                                      sizeof(struct iphdr);
+               dev->mtu = tdev->mtu;
+       }
+       dev->iflink = tunnel->parms.link;
+       return dev->mtu;
+}
+
+static int
+vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+       int err = 0;
+       struct ip_tunnel_parm p;
+       struct ip_tunnel *t;
+       struct net *net = dev_net(dev);
+       struct vti_net *ipn = net_generic(net, vti_net_id);
+
+       switch (cmd) {
+       case SIOCGETTUNNEL:
+               t = NULL;
+               if (dev == ipn->fb_tunnel_dev) {
+                       if (copy_from_user(&p, ifr->ifr_ifru.ifru_data,
+                                          sizeof(p))) {
+                               err = -EFAULT;
+                               break;
+                       }
+                       t = vti_tunnel_locate(net, &p, 0);
+               }
+               if (t == NULL)
+                       t = netdev_priv(dev);
+               memcpy(&p, &t->parms, sizeof(p));
+               p.i_flags |= GRE_KEY | VTI_ISVTI;
+               p.o_flags |= GRE_KEY;
+               if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
+                       err = -EFAULT;
+               break;
+
+       case SIOCADDTUNNEL:
+       case SIOCCHGTUNNEL:
+               err = -EPERM;
+               if (!capable(CAP_NET_ADMIN))
+                       goto done;
+
+               err = -EFAULT;
+               if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
+                       goto done;
+
+               err = -EINVAL;
+               if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
+                   p.iph.ihl != 5)
+                       goto done;
+
+               t = vti_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
+
+               if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
+                       if (t != NULL) {
+                               if (t->dev != dev) {
+                                       err = -EEXIST;
+                                       break;
+                               }
+                       } else {
+                               if (((dev->flags&IFF_POINTOPOINT) &&
+                                   !p.iph.daddr) ||
+                                   (!(dev->flags&IFF_POINTOPOINT) &&
+                                   p.iph.daddr)) {
+                                       err = -EINVAL;
+                                       break;
+                               }
+                               t = netdev_priv(dev);
+                               vti_tunnel_unlink(ipn, t);
+                               synchronize_net();
+                               t->parms.iph.saddr = p.iph.saddr;
+                               t->parms.iph.daddr = p.iph.daddr;
+                               t->parms.i_key = p.i_key;
+                               t->parms.o_key = p.o_key;
+                               t->parms.iph.protocol = IPPROTO_IPIP;
+                               memcpy(dev->dev_addr, &p.iph.saddr, 4);
+                               memcpy(dev->broadcast, &p.iph.daddr, 4);
+                               vti_tunnel_link(ipn, t);
+                               netdev_state_change(dev);
+                       }
+               }
+
+               if (t) {
+                       err = 0;
+                       if (cmd == SIOCCHGTUNNEL) {
+                               t->parms.i_key = p.i_key;
+                               t->parms.o_key = p.o_key;
+                               if (t->parms.link != p.link) {
+                                       t->parms.link = p.link;
+                                       vti_tunnel_bind_dev(dev);
+                                       netdev_state_change(dev);
+                               }
+                       }
+                       p.i_flags |= GRE_KEY | VTI_ISVTI;
+                       p.o_flags |= GRE_KEY;
+                       if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms,
+                                        sizeof(p)))
+                               err = -EFAULT;
+               } else
+                       err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
+               break;
+
+       case SIOCDELTUNNEL:
+               err = -EPERM;
+               if (!capable(CAP_NET_ADMIN))
+                       goto done;
+
+               if (dev == ipn->fb_tunnel_dev) {
+                       err = -EFAULT;
+                       if (copy_from_user(&p, ifr->ifr_ifru.ifru_data,
+                                          sizeof(p)))
+                               goto done;
+                       err = -ENOENT;
+
+                       t = vti_tunnel_locate(net, &p, 0);
+                       if (t == NULL)
+                               goto done;
+                       err = -EPERM;
+                       if (t->dev == ipn->fb_tunnel_dev)
+                               goto done;
+                       dev = t->dev;
+               }
+               unregister_netdevice(dev);
+               err = 0;
+               break;
+
+       default:
+               err = -EINVAL;
+       }
+
+done:
+       return err;
+}
+
+static int vti_tunnel_change_mtu(struct net_device *dev, int new_mtu)
+{
+       if (new_mtu < 68 || new_mtu > 0xFFF8)
+               return -EINVAL;
+       dev->mtu = new_mtu;
+       return 0;
+}
+
+static const struct net_device_ops vti_netdev_ops = {
+       .ndo_init       = vti_tunnel_init,
+       .ndo_uninit     = vti_tunnel_uninit,
+       .ndo_start_xmit = vti_tunnel_xmit,
+       .ndo_do_ioctl   = vti_tunnel_ioctl,
+       .ndo_change_mtu = vti_tunnel_change_mtu,
+       .ndo_get_stats64 = vti_get_stats64,
+};
+
+static void vti_dev_free(struct net_device *dev)
+{
+       free_percpu(dev->tstats);
+       free_netdev(dev);
+}
+
+static void vti_tunnel_setup(struct net_device *dev)
+{
+       dev->netdev_ops         = &vti_netdev_ops;
+       dev->destructor         = vti_dev_free;
+
+       dev->type               = ARPHRD_TUNNEL;
+       dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
+       dev->mtu                = ETH_DATA_LEN;
+       dev->flags              = IFF_NOARP;
+       dev->iflink             = 0;
+       dev->addr_len           = 4;
+       dev->features           |= NETIF_F_NETNS_LOCAL;
+       dev->features           |= NETIF_F_LLTX;
+       dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
+}
+
+static int vti_tunnel_init(struct net_device *dev)
+{
+       struct ip_tunnel *tunnel = netdev_priv(dev);
+
+       tunnel->dev = dev;
+       strcpy(tunnel->parms.name, dev->name);
+
+       memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
+       memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
+
+       dev->tstats = alloc_percpu(struct pcpu_tstats);
+       if (!dev->tstats)
+               return -ENOMEM;
+
+       return 0;
+}
+
+static int __net_init vti_fb_tunnel_init(struct net_device *dev)
+{
+       struct ip_tunnel *tunnel = netdev_priv(dev);
+       struct iphdr *iph = &tunnel->parms.iph;
+       struct vti_net *ipn = net_generic(dev_net(dev), vti_net_id);
+
+       tunnel->dev = dev;
+       strcpy(tunnel->parms.name, dev->name);
+
+       iph->version            = 4;
+       iph->protocol           = IPPROTO_IPIP;
+       iph->ihl                = 5;
+
+       dev->tstats = alloc_percpu(struct pcpu_tstats);
+       if (!dev->tstats)
+               return -ENOMEM;
+
+       dev_hold(dev);
+       rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);
+       return 0;
+}
+
+static struct xfrm_tunnel vti_handler __read_mostly = {
+       .handler        =       vti_rcv,
+       .err_handler    =       vti_err,
+       .priority       =       1,
+};
+
+static void vti_destroy_tunnels(struct vti_net *ipn, struct list_head *head)
+{
+       int prio;
+
+       for (prio = 1; prio < 4; prio++) {
+               int h;
+               for (h = 0; h < HASH_SIZE; h++) {
+                       struct ip_tunnel *t;
+
+                       t = rtnl_dereference(ipn->tunnels[prio][h]);
+                       while (t != NULL) {
+                               unregister_netdevice_queue(t->dev, head);
+                               t = rtnl_dereference(t->next);
+                       }
+               }
+       }
+}
+
+static int __net_init vti_init_net(struct net *net)
+{
+       int err;
+       struct vti_net *ipn = net_generic(net, vti_net_id);
+
+       ipn->tunnels[0] = ipn->tunnels_wc;
+       ipn->tunnels[1] = ipn->tunnels_l;
+       ipn->tunnels[2] = ipn->tunnels_r;
+       ipn->tunnels[3] = ipn->tunnels_r_l;
+
+       ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
+                                         "ip_vti0",
+                                         vti_tunnel_setup);
+       if (!ipn->fb_tunnel_dev) {
+               err = -ENOMEM;
+               goto err_alloc_dev;
+       }
+       dev_net_set(ipn->fb_tunnel_dev, net);
+
+       err = vti_fb_tunnel_init(ipn->fb_tunnel_dev);
+       if (err)
+               goto err_reg_dev;
+       ipn->fb_tunnel_dev->rtnl_link_ops = &vti_link_ops;
+
+       err = register_netdev(ipn->fb_tunnel_dev);
+       if (err)
+               goto err_reg_dev;
+       return 0;
+
+err_reg_dev:
+       vti_dev_free(ipn->fb_tunnel_dev);
+err_alloc_dev:
+       /* nothing */
+       return err;
+}
+
+static void __net_exit vti_exit_net(struct net *net)
+{
+       struct vti_net *ipn = net_generic(net, vti_net_id);
+       LIST_HEAD(list);
+
+       rtnl_lock();
+       vti_destroy_tunnels(ipn, &list);
+       unregister_netdevice_many(&list);
+       rtnl_unlock();
+}
+
+static struct pernet_operations vti_net_ops = {
+       .init = vti_init_net,
+       .exit = vti_exit_net,
+       .id   = &vti_net_id,
+       .size = sizeof(struct vti_net),
+};
+
+static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
+{
+       return 0;
+}
+
+static void vti_netlink_parms(struct nlattr *data[],
+                             struct ip_tunnel_parm *parms)
+{
+       memset(parms, 0, sizeof(*parms));
+
+       parms->iph.protocol = IPPROTO_IPIP;
+
+       if (!data)
+               return;
+
+       if (data[IFLA_VTI_LINK])
+               parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
+
+       if (data[IFLA_VTI_IKEY])
+               parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
+
+       if (data[IFLA_VTI_OKEY])
+               parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
+
+       if (data[IFLA_VTI_LOCAL])
+               parms->iph.saddr = nla_get_be32(data[IFLA_VTI_LOCAL]);
+
+       if (data[IFLA_VTI_REMOTE])
+               parms->iph.daddr = nla_get_be32(data[IFLA_VTI_REMOTE]);
+
+}
+
+static int vti_newlink(struct net *src_net, struct net_device *dev,
+                      struct nlattr *tb[], struct nlattr *data[])
+{
+       struct ip_tunnel *nt;
+       struct net *net = dev_net(dev);
+       struct vti_net *ipn = net_generic(net, vti_net_id);
+       int mtu;
+       int err;
+
+       nt = netdev_priv(dev);
+       vti_netlink_parms(data, &nt->parms);
+
+       if (vti_tunnel_locate(net, &nt->parms, 0))
+               return -EEXIST;
+
+       mtu = vti_tunnel_bind_dev(dev);
+       if (!tb[IFLA_MTU])
+               dev->mtu = mtu;
+
+       err = register_netdevice(dev);
+       if (err)
+               goto out;
+
+       dev_hold(dev);
+       vti_tunnel_link(ipn, nt);
+
+out:
+       return err;
+}
+
+static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
+                         struct nlattr *data[])
+{
+       struct ip_tunnel *t, *nt;
+       struct net *net = dev_net(dev);
+       struct vti_net *ipn = net_generic(net, vti_net_id);
+       struct ip_tunnel_parm p;
+       int mtu;
+
+       if (dev == ipn->fb_tunnel_dev)
+               return -EINVAL;
+
+       nt = netdev_priv(dev);
+       vti_netlink_parms(data, &p);
+
+       t = vti_tunnel_locate(net, &p, 0);
+
+       if (t) {
+               if (t->dev != dev)
+                       return -EEXIST;
+       } else {
+               t = nt;
+
+               vti_tunnel_unlink(ipn, t);
+               t->parms.iph.saddr = p.iph.saddr;
+               t->parms.iph.daddr = p.iph.daddr;
+               t->parms.i_key = p.i_key;
+               t->parms.o_key = p.o_key;
+               if (dev->type != ARPHRD_ETHER) {
+                       memcpy(dev->dev_addr, &p.iph.saddr, 4);
+                       memcpy(dev->broadcast, &p.iph.daddr, 4);
+               }
+               vti_tunnel_link(ipn, t);
+               netdev_state_change(dev);
+       }
+
+       if (t->parms.link != p.link) {
+               t->parms.link = p.link;
+               mtu = vti_tunnel_bind_dev(dev);
+               if (!tb[IFLA_MTU])
+                       dev->mtu = mtu;
+               netdev_state_change(dev);
+       }
+
+       return 0;
+}
+
+static size_t vti_get_size(const struct net_device *dev)
+{
+       return
+               /* IFLA_VTI_LINK */
+               nla_total_size(4) +
+               /* IFLA_VTI_IKEY */
+               nla_total_size(4) +
+               /* IFLA_VTI_OKEY */
+               nla_total_size(4) +
+               /* IFLA_VTI_LOCAL */
+               nla_total_size(4) +
+               /* IFLA_VTI_REMOTE */
+               nla_total_size(4) +
+               0;
+}
+
+static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+       struct ip_tunnel *t = netdev_priv(dev);
+       struct ip_tunnel_parm *p = &t->parms;
+
+       nla_put_u32(skb, IFLA_VTI_LINK, p->link);
+       nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
+       nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
+       nla_put_be32(skb, IFLA_VTI_LOCAL, p->iph.saddr);
+       nla_put_be32(skb, IFLA_VTI_REMOTE, p->iph.daddr);
+
+       return 0;
+}
+
+static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
+       [IFLA_VTI_LINK]         = { .type = NLA_U32 },
+       [IFLA_VTI_IKEY]         = { .type = NLA_U32 },
+       [IFLA_VTI_OKEY]         = { .type = NLA_U32 },
+       [IFLA_VTI_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
+       [IFLA_VTI_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
+};
+
+static struct rtnl_link_ops vti_link_ops __read_mostly = {
+       .kind           = "vti",
+       .maxtype        = IFLA_VTI_MAX,
+       .policy         = vti_policy,
+       .priv_size      = sizeof(struct ip_tunnel),
+       .setup          = vti_tunnel_setup,
+       .validate       = vti_tunnel_validate,
+       .newlink        = vti_newlink,
+       .changelink     = vti_changelink,
+       .get_size       = vti_get_size,
+       .fill_info      = vti_fill_info,
+};
+
+static int __init vti_init(void)
+{
+       int err;
+
+       pr_info("IPv4 over IPSec tunneling driver\n");
+
+       err = register_pernet_device(&vti_net_ops);
+       if (err < 0)
+               return err;
+       err = xfrm4_mode_tunnel_input_register(&vti_handler);
+       if (err < 0) {
+               unregister_pernet_device(&vti_net_ops);
+               pr_info(KERN_INFO "vti init: can't register tunnel\n");
+       }
+
+       err = rtnl_link_register(&vti_link_ops);
+       if (err < 0)
+               goto rtnl_link_failed;
+
+       return err;
+
+rtnl_link_failed:
+       xfrm4_mode_tunnel_input_deregister(&vti_handler);
+       unregister_pernet_device(&vti_net_ops);
+       return err;
+}
+
+static void __exit vti_fini(void)
+{
+       rtnl_link_unregister(&vti_link_ops);
+       if (xfrm4_mode_tunnel_input_deregister(&vti_handler))
+               pr_info("vti close: can't deregister tunnel\n");
+
+       unregister_pernet_device(&vti_net_ops);
+}
+
+module_init(vti_init);
+module_exit(vti_fini);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("vti");
+MODULE_ALIAS_NETDEV("ip_vti0");