net/ipv4/ip_vti.c

   1 /*
   2  *      Linux NET3: IP/IP protocol decoder modified to support
   3  *                  virtual tunnel interface
   4  *
   5  *      Authors:
   6  *              Saurabh Mohan (saurabh.mohan@vyatta.com) 05/07/2012
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  *
  13  */
  14
  15 /*
  16    This version of net/ipv4/ip_vti.c is cloned of net/ipv4/ipip.c
  17
  18    For comments look at net/ipv4/ip_gre.c --ANK
  19  */
  20
  21
  22 #include <linux/capability.h>
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include <linux/kernel.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/skbuff.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/in.h>
  30 #include <linux/tcp.h>
  31 #include <linux/udp.h>
  32 #include <linux/if_arp.h>
  33 #include <linux/mroute.h>
  34 #include <linux/init.h>
  35 #include <linux/netfilter_ipv4.h>
  36 #include <linux/if_ether.h>
  37
  38 #include <net/sock.h>
  39 #include <net/ip.h>
  40 #include <net/icmp.h>
  41 #include <net/ip_tunnels.h>
  42 #include <net/inet_ecn.h>
  43 #include <net/xfrm.h>
  44 #include <net/net_namespace.h>
  45 #include <net/netns/generic.h>
  46
  47 static struct rtnl_link_ops vti_link_ops __read_mostly;
  48
  49 static int vti_net_id __read_mostly;
  50 static int vti_tunnel_init(struct net_device *dev);
  51
  52 /* We dont digest the packet therefore let the packet pass */
  53 static int vti_rcv(struct sk_buff *skb)
  54 {
  55         struct ip_tunnel *tunnel;
  56         const struct iphdr *iph = ip_hdr(skb);
  57         struct net *net = dev_net(skb->dev);
  58         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
  59
  60         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
  61                                   iph->saddr, iph->daddr, 0);
  62         if (tunnel != NULL) {
  63                 struct pcpu_sw_netstats *tstats;
  64                 u32 oldmark = skb->mark;
  65                 int ret;
  66
  67
  68                 /* temporarily mark the skb with the tunnel o_key, to
  69                  * only match policies with this mark.
  70                  */
  71                 skb->mark = be32_to_cpu(tunnel->parms.o_key);
  72                 ret = xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb);
  73                 skb->mark = oldmark;
  74                 if (!ret)
  75                         return -1;
  76
  77                 tstats = this_cpu_ptr(tunnel->dev->tstats);
  78                 u64_stats_update_begin(&tstats->syncp);
  79                 tstats->rx_packets++;
  80                 tstats->rx_bytes += skb->len;
  81                 u64_stats_update_end(&tstats->syncp);
  82
  83                 secpath_reset(skb);
  84                 skb->dev = tunnel->dev;
  85                 return 1;
  86         }
  87
  88         return -1;
  89 }
  90
  91 /* This function assumes it is being called from dev_queue_xmit()
  92  * and that skb is filled properly by that function.
  93  */
  94
  95 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
  96 {
  97         struct ip_tunnel *tunnel = netdev_priv(dev);
  98         struct iphdr  *tiph = &tunnel->parms.iph;
  99         u8     tos;
 100         struct rtable *rt;              /* Route to the other host */
 101         struct net_device *tdev;        /* Device to other host */
 102         struct iphdr  *old_iph = ip_hdr(skb);
 103         __be32 dst = tiph->daddr;
 104         struct flowi4 fl4;
 105         int err;
 106
 107         if (skb->protocol != htons(ETH_P_IP))
 108                 goto tx_error;
 109
 110         tos = old_iph->tos;
 111
 112         memset(&fl4, 0, sizeof(fl4));
 113         flowi4_init_output(&fl4, tunnel->parms.link,
 114                            be32_to_cpu(tunnel->parms.o_key), RT_TOS(tos),
 115                            RT_SCOPE_UNIVERSE,
 116                            IPPROTO_IPIP, 0,
 117                            dst, tiph->saddr, 0, 0);
 118         rt = ip_route_output_key(dev_net(dev), &fl4);
 119         if (IS_ERR(rt)) {
 120                 dev->stats.tx_carrier_errors++;
 121                 goto tx_error_icmp;
 122         }
 123         /* if there is no transform then this tunnel is not functional.
 124          * Or if the xfrm is not mode tunnel.
 125          */
 126         if (!rt->dst.xfrm ||
 127             rt->dst.xfrm->props.mode != XFRM_MODE_TUNNEL) {
 128                 dev->stats.tx_carrier_errors++;
 129                 ip_rt_put(rt);
 130                 goto tx_error_icmp;
 131         }
 132         tdev = rt->dst.dev;
 133
 134         if (tdev == dev) {
 135                 ip_rt_put(rt);
 136                 dev->stats.collisions++;
 137                 goto tx_error;
 138         }
 139
 140         if (tunnel->err_count > 0) {
 141                 if (time_before(jiffies,
 142                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 143                         tunnel->err_count--;
 144                         dst_link_failure(skb);
 145                 } else
 146                         tunnel->err_count = 0;
 147         }
 148
 149         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 150         skb_dst_drop(skb);
 151         skb_dst_set(skb, &rt->dst);
 152         nf_reset(skb);
 153         skb->dev = skb_dst(skb)->dev;
 154
 155         err = dst_output(skb);
 156         if (net_xmit_eval(err) == 0)
 157                 err = skb->len;
 158         iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 159         return NETDEV_TX_OK;
 160
 161 tx_error_icmp:
 162         dst_link_failure(skb);
 163 tx_error:
 164         dev->stats.tx_errors++;
 165         dev_kfree_skb(skb);
 166         return NETDEV_TX_OK;
 167 }
 168
 169 static int
 170 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 171 {
 172         int err = 0;
 173         struct ip_tunnel_parm p;
 174
 175         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 176                 return -EFAULT;
 177
 178         if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
 179                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 180                     p.iph.ihl != 5)
 181                         return -EINVAL;
 182         }
 183
 184         err = ip_tunnel_ioctl(dev, &p, cmd);
 185         if (err)
 186                 return err;
 187
 188         if (cmd != SIOCDELTUNNEL) {
 189                 p.i_flags |= GRE_KEY | VTI_ISVTI;
 190                 p.o_flags |= GRE_KEY;
 191         }
 192
 193         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 194                 return -EFAULT;
 195         return 0;
 196 }
 197
 198 static const struct net_device_ops vti_netdev_ops = {
 199         .ndo_init       = vti_tunnel_init,
 200         .ndo_uninit     = ip_tunnel_uninit,
 201         .ndo_start_xmit = vti_tunnel_xmit,
 202         .ndo_do_ioctl   = vti_tunnel_ioctl,
 203         .ndo_change_mtu = ip_tunnel_change_mtu,
 204         .ndo_get_stats64 = ip_tunnel_get_stats64,
 205 };
 206
 207 static void vti_tunnel_setup(struct net_device *dev)
 208 {
 209         dev->netdev_ops         = &vti_netdev_ops;
 210         ip_tunnel_setup(dev, vti_net_id);
 211 }
 212
 213 static int vti_tunnel_init(struct net_device *dev)
 214 {
 215         struct ip_tunnel *tunnel = netdev_priv(dev);
 216         struct iphdr *iph = &tunnel->parms.iph;
 217
 218         memcpy(dev->dev_addr, &iph->saddr, 4);
 219         memcpy(dev->broadcast, &iph->daddr, 4);
 220
 221         dev->type               = ARPHRD_TUNNEL;
 222         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 223         dev->mtu                = ETH_DATA_LEN;
 224         dev->flags              = IFF_NOARP;
 225         dev->iflink             = 0;
 226         dev->addr_len           = 4;
 227         dev->features           |= NETIF_F_NETNS_LOCAL;
 228         dev->features           |= NETIF_F_LLTX;
 229         dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
 230
 231         return ip_tunnel_init(dev);
 232 }
 233
 234 static void __net_init vti_fb_tunnel_init(struct net_device *dev)
 235 {
 236         struct ip_tunnel *tunnel = netdev_priv(dev);
 237         struct iphdr *iph = &tunnel->parms.iph;
 238
 239         iph->version            = 4;
 240         iph->protocol           = IPPROTO_IPIP;
 241         iph->ihl                = 5;
 242 }
 243
 244 static struct xfrm_tunnel_notifier vti_handler __read_mostly = {
 245         .handler        =       vti_rcv,
 246         .priority       =       1,
 247 };
 248
 249 static int __net_init vti_init_net(struct net *net)
 250 {
 251         int err;
 252         struct ip_tunnel_net *itn;
 253
 254         err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0");
 255         if (err)
 256                 return err;
 257         itn = net_generic(net, vti_net_id);
 258         vti_fb_tunnel_init(itn->fb_tunnel_dev);
 259         return 0;
 260 }
 261
 262 static void __net_exit vti_exit_net(struct net *net)
 263 {
 264         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
 265         ip_tunnel_delete_net(itn, &vti_link_ops);
 266 }
 267
 268 static struct pernet_operations vti_net_ops = {
 269         .init = vti_init_net,
 270         .exit = vti_exit_net,
 271         .id   = &vti_net_id,
 272         .size = sizeof(struct ip_tunnel_net),
 273 };
 274
 275 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
 276 {
 277         return 0;
 278 }
 279
 280 static void vti_netlink_parms(struct nlattr *data[],
 281                               struct ip_tunnel_parm *parms)
 282 {
 283         memset(parms, 0, sizeof(*parms));
 284
 285         parms->iph.protocol = IPPROTO_IPIP;
 286
 287         if (!data)
 288                 return;
 289
 290         if (data[IFLA_VTI_LINK])
 291                 parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
 292
 293         if (data[IFLA_VTI_IKEY])
 294                 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
 295
 296         if (data[IFLA_VTI_OKEY])
 297                 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
 298
 299         if (data[IFLA_VTI_LOCAL])
 300                 parms->iph.saddr = nla_get_be32(data[IFLA_VTI_LOCAL]);
 301
 302         if (data[IFLA_VTI_REMOTE])
 303                 parms->iph.daddr = nla_get_be32(data[IFLA_VTI_REMOTE]);
 304
 305 }
 306
 307 static int vti_newlink(struct net *src_net, struct net_device *dev,
 308                        struct nlattr *tb[], struct nlattr *data[])
 309 {
 310         struct ip_tunnel_parm parms;
 311
 312         vti_netlink_parms(data, &parms);
 313         return ip_tunnel_newlink(dev, tb, &parms);
 314 }
 315
 316 static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
 317                           struct nlattr *data[])
 318 {
 319         struct ip_tunnel_parm p;
 320
 321         vti_netlink_parms(data, &p);
 322         return ip_tunnel_changelink(dev, tb, &p);
 323 }
 324
 325 static size_t vti_get_size(const struct net_device *dev)
 326 {
 327         return
 328                 /* IFLA_VTI_LINK */
 329                 nla_total_size(4) +
 330                 /* IFLA_VTI_IKEY */
 331                 nla_total_size(4) +
 332                 /* IFLA_VTI_OKEY */
 333                 nla_total_size(4) +
 334                 /* IFLA_VTI_LOCAL */
 335                 nla_total_size(4) +
 336                 /* IFLA_VTI_REMOTE */
 337                 nla_total_size(4) +
 338                 0;
 339 }
 340
 341 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
 342 {
 343         struct ip_tunnel *t = netdev_priv(dev);
 344         struct ip_tunnel_parm *p = &t->parms;
 345
 346         nla_put_u32(skb, IFLA_VTI_LINK, p->link);
 347         nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
 348         nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
 349         nla_put_be32(skb, IFLA_VTI_LOCAL, p->iph.saddr);
 350         nla_put_be32(skb, IFLA_VTI_REMOTE, p->iph.daddr);
 351
 352         return 0;
 353 }
 354
 355 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
 356         [IFLA_VTI_LINK]         = { .type = NLA_U32 },
 357         [IFLA_VTI_IKEY]         = { .type = NLA_U32 },
 358         [IFLA_VTI_OKEY]         = { .type = NLA_U32 },
 359         [IFLA_VTI_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
 360         [IFLA_VTI_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
 361 };
 362
 363 static struct rtnl_link_ops vti_link_ops __read_mostly = {
 364         .kind           = "vti",
 365         .maxtype        = IFLA_VTI_MAX,
 366         .policy         = vti_policy,
 367         .priv_size      = sizeof(struct ip_tunnel),
 368         .setup          = vti_tunnel_setup,
 369         .validate       = vti_tunnel_validate,
 370         .newlink        = vti_newlink,
 371         .changelink     = vti_changelink,
 372         .get_size       = vti_get_size,
 373         .fill_info      = vti_fill_info,
 374 };
 375
 376 static int __init vti_init(void)
 377 {
 378         int err;
 379
 380         pr_info("IPv4 over IPSec tunneling driver\n");
 381
 382         err = register_pernet_device(&vti_net_ops);
 383         if (err < 0)
 384                 return err;
 385         err = xfrm4_mode_tunnel_input_register(&vti_handler);
 386         if (err < 0) {
 387                 unregister_pernet_device(&vti_net_ops);
 388                 pr_info("vti init: can't register tunnel\n");
 389         }
 390
 391         err = rtnl_link_register(&vti_link_ops);
 392         if (err < 0)
 393                 goto rtnl_link_failed;
 394
 395         return err;
 396
 397 rtnl_link_failed:
 398         xfrm4_mode_tunnel_input_deregister(&vti_handler);
 399         unregister_pernet_device(&vti_net_ops);
 400         return err;
 401 }
 402
 403 static void __exit vti_fini(void)
 404 {
 405         rtnl_link_unregister(&vti_link_ops);
 406         if (xfrm4_mode_tunnel_input_deregister(&vti_handler))
 407                 pr_info("vti close: can't deregister tunnel\n");
 408
 409         unregister_pernet_device(&vti_net_ops);
 410 }
 411
 412 module_init(vti_init);
 413 module_exit(vti_fini);
 414 MODULE_LICENSE("GPL");
 415 MODULE_ALIAS_RTNL_LINK("vti");
 416 MODULE_ALIAS_NETDEV("ip_vti0");