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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/init.h>
34#include <linux/netfilter_ipv4.h>
35#include <linux/if_ether.h>
36#include <linux/icmpv6.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
47static struct rtnl_link_ops vti_link_ops __read_mostly;
48
49static int vti_net_id __read_mostly;
50static int vti_tunnel_init(struct net_device *dev);
51
52static int vti_input(struct sk_buff *skb, int nexthdr, __be32 spi,
53 int encap_type)
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) {
63 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
64 goto drop;
65
66 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = tunnel;
67
68 return xfrm_input(skb, nexthdr, spi, encap_type);
69 }
70
71 return -EINVAL;
72drop:
73 kfree_skb(skb);
74 return 0;
75}
76
77static int vti_rcv(struct sk_buff *skb)
78{
79 XFRM_SPI_SKB_CB(skb)->family = AF_INET;
80 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
81
82 return vti_input(skb, ip_hdr(skb)->protocol, 0, 0);
83}
84
85static int vti_rcv_cb(struct sk_buff *skb, int err)
86{
87 unsigned short family;
88 struct net_device *dev;
89 struct pcpu_sw_netstats *tstats;
90 struct xfrm_state *x;
91 struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4;
92 u32 orig_mark = skb->mark;
93 int ret;
94
95 if (!tunnel)
96 return 1;
97
98 dev = tunnel->dev;
99
100 if (err) {
101 dev->stats.rx_errors++;
102 dev->stats.rx_dropped++;
103
104 return 0;
105 }
106
107 x = xfrm_input_state(skb);
108 family = x->inner_mode->afinfo->family;
109
110 skb->mark = be32_to_cpu(tunnel->parms.i_key);
111 ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
112 skb->mark = orig_mark;
113
114 if (!ret)
115 return -EPERM;
116
117 skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(skb->dev)));
118 skb->dev = dev;
119
120 tstats = this_cpu_ptr(dev->tstats);
121
122 u64_stats_update_begin(&tstats->syncp);
123 tstats->rx_packets++;
124 tstats->rx_bytes += skb->len;
125 u64_stats_update_end(&tstats->syncp);
126
127 return 0;
128}
129
130static bool vti_state_check(const struct xfrm_state *x, __be32 dst, __be32 src)
131{
132 xfrm_address_t *daddr = (xfrm_address_t *)&dst;
133 xfrm_address_t *saddr = (xfrm_address_t *)&src;
134
135 /* if there is no transform then this tunnel is not functional.
136 * Or if the xfrm is not mode tunnel.
137 */
138 if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
139 x->props.family != AF_INET)
140 return false;
141
142 if (!dst)
143 return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET);
144
145 if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET))
146 return false;
147
148 return true;
149}
150
151static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
152 struct flowi *fl)
153{
154 struct ip_tunnel *tunnel = netdev_priv(dev);
155 struct ip_tunnel_parm *parms = &tunnel->parms;
156 struct dst_entry *dst = skb_dst(skb);
157 struct net_device *tdev; /* Device to other host */
158 int err;
159 int mtu;
160
161 if (!dst) {
162 dev->stats.tx_carrier_errors++;
163 goto tx_error_icmp;
164 }
165
166 dst_hold(dst);
167 dst = xfrm_lookup(tunnel->net, dst, fl, NULL, 0);
168 if (IS_ERR(dst)) {
169 dev->stats.tx_carrier_errors++;
170 goto tx_error_icmp;
171 }
172
173 if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {
174 dev->stats.tx_carrier_errors++;
175 dst_release(dst);
176 goto tx_error_icmp;
177 }
178
179 tdev = dst->dev;
180
181 if (tdev == dev) {
182 dst_release(dst);
183 dev->stats.collisions++;
184 goto tx_error;
185 }
186
187 if (tunnel->err_count > 0) {
188 if (time_before(jiffies,
189 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
190 tunnel->err_count--;
191 dst_link_failure(skb);
192 } else
193 tunnel->err_count = 0;
194 }
195
196 mtu = dst_mtu(dst);
197 if (skb->len > mtu) {
198 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
199 if (skb->protocol == htons(ETH_P_IP)) {
200 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
201 htonl(mtu));
202 } else {
203 if (mtu < IPV6_MIN_MTU)
204 mtu = IPV6_MIN_MTU;
205
206 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
207 }
208
209 dst_release(dst);
210 goto tx_error;
211 }
212
213 skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
214 skb_dst_set(skb, dst);
215 skb->dev = skb_dst(skb)->dev;
216
217 err = dst_output(tunnel->net, skb->sk, skb);
218 if (net_xmit_eval(err) == 0)
219 err = skb->len;
220 iptunnel_xmit_stats(dev, err);
221 return NETDEV_TX_OK;
222
223tx_error_icmp:
224 dst_link_failure(skb);
225tx_error:
226 dev->stats.tx_errors++;
227 kfree_skb(skb);
228 return NETDEV_TX_OK;
229}
230
231/* This function assumes it is being called from dev_queue_xmit()
232 * and that skb is filled properly by that function.
233 */
234static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
235{
236 struct ip_tunnel *tunnel = netdev_priv(dev);
237 struct flowi fl;
238
239 memset(&fl, 0, sizeof(fl));
240
241 switch (skb->protocol) {
242 case htons(ETH_P_IP):
243 xfrm_decode_session(skb, &fl, AF_INET);
244 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
245 break;
246 case htons(ETH_P_IPV6):
247 xfrm_decode_session(skb, &fl, AF_INET6);
248 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
249 break;
250 default:
251 dev->stats.tx_errors++;
252 dev_kfree_skb(skb);
253 return NETDEV_TX_OK;
254 }
255
256 /* override mark with tunnel output key */
257 fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key);
258
259 return vti_xmit(skb, dev, &fl);
260}
261
262static int vti4_err(struct sk_buff *skb, u32 info)
263{
264 __be32 spi;
265 __u32 mark;
266 struct xfrm_state *x;
267 struct ip_tunnel *tunnel;
268 struct ip_esp_hdr *esph;
269 struct ip_auth_hdr *ah ;
270 struct ip_comp_hdr *ipch;
271 struct net *net = dev_net(skb->dev);
272 const struct iphdr *iph = (const struct iphdr *)skb->data;
273 int protocol = iph->protocol;
274 struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
275
276 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
277 iph->daddr, iph->saddr, 0);
278 if (!tunnel)
279 return -1;
280
281 mark = be32_to_cpu(tunnel->parms.o_key);
282
283 switch (protocol) {
284 case IPPROTO_ESP:
285 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
286 spi = esph->spi;
287 break;
288 case IPPROTO_AH:
289 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
290 spi = ah->spi;
291 break;
292 case IPPROTO_COMP:
293 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
294 spi = htonl(ntohs(ipch->cpi));
295 break;
296 default:
297 return 0;
298 }
299
300 switch (icmp_hdr(skb)->type) {
301 case ICMP_DEST_UNREACH:
302 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
303 return 0;
304 case ICMP_REDIRECT:
305 break;
306 default:
307 return 0;
308 }
309
310 x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
311 spi, protocol, AF_INET);
312 if (!x)
313 return 0;
314
315 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
316 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0);
317 else
318 ipv4_redirect(skb, net, 0, 0, protocol, 0);
319 xfrm_state_put(x);
320
321 return 0;
322}
323
324static int
325vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
326{
327 int err = 0;
328 struct ip_tunnel_parm p;
329
330 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
331 return -EFAULT;
332
333 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
334 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
335 p.iph.ihl != 5)
336 return -EINVAL;
337 }
338
339 if (!(p.i_flags & GRE_KEY))
340 p.i_key = 0;
341 if (!(p.o_flags & GRE_KEY))
342 p.o_key = 0;
343
344 p.i_flags = VTI_ISVTI;
345
346 err = ip_tunnel_ioctl(dev, &p, cmd);
347 if (err)
348 return err;
349
350 if (cmd != SIOCDELTUNNEL) {
351 p.i_flags |= GRE_KEY;
352 p.o_flags |= GRE_KEY;
353 }
354
355 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
356 return -EFAULT;
357 return 0;
358}
359
360static const struct net_device_ops vti_netdev_ops = {
361 .ndo_init = vti_tunnel_init,
362 .ndo_uninit = ip_tunnel_uninit,
363 .ndo_start_xmit = vti_tunnel_xmit,
364 .ndo_do_ioctl = vti_tunnel_ioctl,
365 .ndo_change_mtu = ip_tunnel_change_mtu,
366 .ndo_get_stats64 = ip_tunnel_get_stats64,
367 .ndo_get_iflink = ip_tunnel_get_iflink,
368};
369
370static void vti_tunnel_setup(struct net_device *dev)
371{
372 dev->netdev_ops = &vti_netdev_ops;
373 dev->type = ARPHRD_TUNNEL;
374 ip_tunnel_setup(dev, vti_net_id);
375}
376
377static int vti_tunnel_init(struct net_device *dev)
378{
379 struct ip_tunnel *tunnel = netdev_priv(dev);
380 struct iphdr *iph = &tunnel->parms.iph;
381
382 memcpy(dev->dev_addr, &iph->saddr, 4);
383 memcpy(dev->broadcast, &iph->daddr, 4);
384
385 dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr);
386 dev->mtu = ETH_DATA_LEN;
387 dev->flags = IFF_NOARP;
388 dev->addr_len = 4;
389 dev->features |= NETIF_F_LLTX;
390 netif_keep_dst(dev);
391
392 return ip_tunnel_init(dev);
393}
394
395static void __net_init vti_fb_tunnel_init(struct net_device *dev)
396{
397 struct ip_tunnel *tunnel = netdev_priv(dev);
398 struct iphdr *iph = &tunnel->parms.iph;
399
400 iph->version = 4;
401 iph->protocol = IPPROTO_IPIP;
402 iph->ihl = 5;
403}
404
405static struct xfrm4_protocol vti_esp4_protocol __read_mostly = {
406 .handler = vti_rcv,
407 .input_handler = vti_input,
408 .cb_handler = vti_rcv_cb,
409 .err_handler = vti4_err,
410 .priority = 100,
411};
412
413static struct xfrm4_protocol vti_ah4_protocol __read_mostly = {
414 .handler = vti_rcv,
415 .input_handler = vti_input,
416 .cb_handler = vti_rcv_cb,
417 .err_handler = vti4_err,
418 .priority = 100,
419};
420
421static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = {
422 .handler = vti_rcv,
423 .input_handler = vti_input,
424 .cb_handler = vti_rcv_cb,
425 .err_handler = vti4_err,
426 .priority = 100,
427};
428
429static int __net_init vti_init_net(struct net *net)
430{
431 int err;
432 struct ip_tunnel_net *itn;
433
434 err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0");
435 if (err)
436 return err;
437 itn = net_generic(net, vti_net_id);
438 vti_fb_tunnel_init(itn->fb_tunnel_dev);
439 return 0;
440}
441
442static void __net_exit vti_exit_net(struct net *net)
443{
444 struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
445 ip_tunnel_delete_net(itn, &vti_link_ops);
446}
447
448static struct pernet_operations vti_net_ops = {
449 .init = vti_init_net,
450 .exit = vti_exit_net,
451 .id = &vti_net_id,
452 .size = sizeof(struct ip_tunnel_net),
453};
454
455static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
456{
457 return 0;
458}
459
460static void vti_netlink_parms(struct nlattr *data[],
461 struct ip_tunnel_parm *parms)
462{
463 memset(parms, 0, sizeof(*parms));
464
465 parms->iph.protocol = IPPROTO_IPIP;
466
467 if (!data)
468 return;
469
470 parms->i_flags = VTI_ISVTI;
471
472 if (data[IFLA_VTI_LINK])
473 parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
474
475 if (data[IFLA_VTI_IKEY])
476 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
477
478 if (data[IFLA_VTI_OKEY])
479 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
480
481 if (data[IFLA_VTI_LOCAL])
482 parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]);
483
484 if (data[IFLA_VTI_REMOTE])
485 parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]);
486
487}
488
489static int vti_newlink(struct net *src_net, struct net_device *dev,
490 struct nlattr *tb[], struct nlattr *data[])
491{
492 struct ip_tunnel_parm parms;
493
494 vti_netlink_parms(data, &parms);
495 return ip_tunnel_newlink(dev, tb, &parms);
496}
497
498static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
499 struct nlattr *data[])
500{
501 struct ip_tunnel_parm p;
502
503 vti_netlink_parms(data, &p);
504 return ip_tunnel_changelink(dev, tb, &p);
505}
506
507static size_t vti_get_size(const struct net_device *dev)
508{
509 return
510 /* IFLA_VTI_LINK */
511 nla_total_size(4) +
512 /* IFLA_VTI_IKEY */
513 nla_total_size(4) +
514 /* IFLA_VTI_OKEY */
515 nla_total_size(4) +
516 /* IFLA_VTI_LOCAL */
517 nla_total_size(4) +
518 /* IFLA_VTI_REMOTE */
519 nla_total_size(4) +
520 0;
521}
522
523static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
524{
525 struct ip_tunnel *t = netdev_priv(dev);
526 struct ip_tunnel_parm *p = &t->parms;
527
528 nla_put_u32(skb, IFLA_VTI_LINK, p->link);
529 nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
530 nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
531 nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr);
532 nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr);
533
534 return 0;
535}
536
537static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
538 [IFLA_VTI_LINK] = { .type = NLA_U32 },
539 [IFLA_VTI_IKEY] = { .type = NLA_U32 },
540 [IFLA_VTI_OKEY] = { .type = NLA_U32 },
541 [IFLA_VTI_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
542 [IFLA_VTI_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
543};
544
545static struct rtnl_link_ops vti_link_ops __read_mostly = {
546 .kind = "vti",
547 .maxtype = IFLA_VTI_MAX,
548 .policy = vti_policy,
549 .priv_size = sizeof(struct ip_tunnel),
550 .setup = vti_tunnel_setup,
551 .validate = vti_tunnel_validate,
552 .newlink = vti_newlink,
553 .changelink = vti_changelink,
554 .dellink = ip_tunnel_dellink,
555 .get_size = vti_get_size,
556 .fill_info = vti_fill_info,
557 .get_link_net = ip_tunnel_get_link_net,
558};
559
560static int __init vti_init(void)
561{
562 const char *msg;
563 int err;
564
565 pr_info("IPv4 over IPsec tunneling driver\n");
566
567 msg = "tunnel device";
568 err = register_pernet_device(&vti_net_ops);
569 if (err < 0)
570 goto pernet_dev_failed;
571
572 msg = "tunnel protocols";
573 err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP);
574 if (err < 0)
575 goto xfrm_proto_esp_failed;
576 err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH);
577 if (err < 0)
578 goto xfrm_proto_ah_failed;
579 err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP);
580 if (err < 0)
581 goto xfrm_proto_comp_failed;
582
583 msg = "netlink interface";
584 err = rtnl_link_register(&vti_link_ops);
585 if (err < 0)
586 goto rtnl_link_failed;
587
588 return err;
589
590rtnl_link_failed:
591 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
592xfrm_proto_comp_failed:
593 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
594xfrm_proto_ah_failed:
595 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
596xfrm_proto_esp_failed:
597 unregister_pernet_device(&vti_net_ops);
598pernet_dev_failed:
599 pr_err("vti init: failed to register %s\n", msg);
600 return err;
601}
602
603static void __exit vti_fini(void)
604{
605 rtnl_link_unregister(&vti_link_ops);
606 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
607 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
608 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
609 unregister_pernet_device(&vti_net_ops);
610}
611
612module_init(vti_init);
613module_exit(vti_fini);
614MODULE_LICENSE("GPL");
615MODULE_ALIAS_RTNL_LINK("vti");
616MODULE_ALIAS_NETDEV("ip_vti0");