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1 | /* |
2 | * Linux NET3: IP/IP protocol decoder. |
3 | * |
4 | * Authors: |
5 | * Sam Lantinga (slouken@cs.ucdavis.edu) 02/01/95 |
6 | * |
7 | * Fixes: |
8 | * Alan Cox : Merged and made usable non modular (its so tiny its silly as |
9 | * a module taking up 2 pages). |
10 | * Alan Cox : Fixed bug with 1.3.18 and IPIP not working (now needs to set skb->h.iph) |
11 | * to keep ip_forward happy. |
12 | * Alan Cox : More fixes for 1.3.21, and firewall fix. Maybe this will work soon 8). |
13 | * Kai Schulte : Fixed #defines for IP_FIREWALL->FIREWALL |
14 | * David Woodhouse : Perform some basic ICMP handling. |
15 | * IPIP Routing without decapsulation. |
16 | * Carlos Picoto : GRE over IP support |
17 | * Alexey Kuznetsov: Reworked. Really, now it is truncated version of ipv4/ip_gre.c. |
18 | * I do not want to merge them together. |
19 | * |
20 | * This program is free software; you can redistribute it and/or |
21 | * modify it under the terms of the GNU General Public License |
22 | * as published by the Free Software Foundation; either version |
23 | * 2 of the License, or (at your option) any later version. |
24 | * |
25 | */ |
26 | |
27 | /* tunnel.c: an IP tunnel driver |
28 | |
29 | The purpose of this driver is to provide an IP tunnel through |
30 | which you can tunnel network traffic transparently across subnets. |
31 | |
32 | This was written by looking at Nick Holloway's dummy driver |
33 | Thanks for the great code! |
34 | |
35 | -Sam Lantinga (slouken@cs.ucdavis.edu) 02/01/95 |
36 | |
37 | Minor tweaks: |
38 | Cleaned up the code a little and added some pre-1.3.0 tweaks. |
39 | dev->hard_header/hard_header_len changed to use no headers. |
40 | Comments/bracketing tweaked. |
41 | Made the tunnels use dev->name not tunnel: when error reporting. |
42 | Added tx_dropped stat |
43 | |
44 | -Alan Cox (alan@lxorguk.ukuu.org.uk) 21 March 95 |
45 | |
46 | Reworked: |
47 | Changed to tunnel to destination gateway in addition to the |
48 | tunnel's pointopoint address |
49 | Almost completely rewritten |
50 | Note: There is currently no firewall or ICMP handling done. |
51 | |
52 | -Sam Lantinga (slouken@cs.ucdavis.edu) 02/13/96 |
53 | |
54 | */ |
55 | |
56 | /* Things I wish I had known when writing the tunnel driver: |
57 | |
58 | When the tunnel_xmit() function is called, the skb contains the |
59 | packet to be sent (plus a great deal of extra info), and dev |
60 | contains the tunnel device that _we_ are. |
61 | |
62 | When we are passed a packet, we are expected to fill in the |
63 | source address with our source IP address. |
64 | |
65 | What is the proper way to allocate, copy and free a buffer? |
66 | After you allocate it, it is a "0 length" chunk of memory |
67 | starting at zero. If you want to add headers to the buffer |
68 | later, you'll have to call "skb_reserve(skb, amount)" with |
69 | the amount of memory you want reserved. Then, you call |
70 | "skb_put(skb, amount)" with the amount of space you want in |
71 | the buffer. skb_put() returns a pointer to the top (#0) of |
72 | that buffer. skb->len is set to the amount of space you have |
73 | "allocated" with skb_put(). You can then write up to skb->len |
74 | bytes to that buffer. If you need more, you can call skb_put() |
75 | again with the additional amount of space you need. You can |
76 | find out how much more space you can allocate by calling |
77 | "skb_tailroom(skb)". |
78 | Now, to add header space, call "skb_push(skb, header_len)". |
79 | This creates space at the beginning of the buffer and returns |
80 | a pointer to this new space. If later you need to strip a |
81 | header from a buffer, call "skb_pull(skb, header_len)". |
82 | skb_headroom() will return how much space is left at the top |
83 | of the buffer (before the main data). Remember, this headroom |
84 | space must be reserved before the skb_put() function is called. |
85 | */ |
86 | |
87 | /* |
88 | This version of net/ipv4/ipip.c is cloned of net/ipv4/ip_gre.c |
89 | |
90 | For comments look at net/ipv4/ip_gre.c --ANK |
91 | */ |
92 | |
93 | |
94 | #include <linux/capability.h> |
95 | #include <linux/module.h> |
96 | #include <linux/types.h> |
97 | #include <linux/kernel.h> |
98 | #include <linux/slab.h> |
99 | #include <asm/uaccess.h> |
100 | #include <linux/skbuff.h> |
101 | #include <linux/netdevice.h> |
102 | #include <linux/in.h> |
103 | #include <linux/tcp.h> |
104 | #include <linux/udp.h> |
105 | #include <linux/if_arp.h> |
106 | #include <linux/mroute.h> |
107 | #include <linux/init.h> |
108 | #include <linux/netfilter_ipv4.h> |
109 | #include <linux/if_ether.h> |
110 | |
111 | #include <net/sock.h> |
112 | #include <net/ip.h> |
113 | #include <net/icmp.h> |
114 | #include <net/ip_tunnels.h> |
115 | #include <net/inet_ecn.h> |
116 | #include <net/xfrm.h> |
117 | #include <net/net_namespace.h> |
118 | #include <net/netns/generic.h> |
119 | |
120 | static bool log_ecn_error = true; |
121 | module_param(log_ecn_error, bool, 0644); |
122 | MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN"); |
123 | |
124 | static int ipip_net_id __read_mostly; |
125 | |
126 | static int ipip_tunnel_init(struct net_device *dev); |
127 | static struct rtnl_link_ops ipip_link_ops __read_mostly; |
128 | |
129 | static int ipip_err(struct sk_buff *skb, u32 info) |
130 | { |
131 | |
132 | /* All the routers (except for Linux) return only |
133 | 8 bytes of packet payload. It means, that precise relaying of |
134 | ICMP in the real Internet is absolutely infeasible. |
135 | */ |
136 | struct net *net = dev_net(skb->dev); |
137 | struct ip_tunnel_net *itn = net_generic(net, ipip_net_id); |
138 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
139 | struct ip_tunnel *t; |
140 | int err; |
141 | const int type = icmp_hdr(skb)->type; |
142 | const int code = icmp_hdr(skb)->code; |
143 | |
144 | err = -ENOENT; |
145 | t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, |
146 | iph->daddr, iph->saddr, 0); |
147 | if (t == NULL) |
148 | goto out; |
149 | |
150 | if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) { |
151 | ipv4_update_pmtu(skb, dev_net(skb->dev), info, |
152 | t->dev->ifindex, 0, IPPROTO_IPIP, 0); |
153 | err = 0; |
154 | goto out; |
155 | } |
156 | |
157 | if (type == ICMP_REDIRECT) { |
158 | ipv4_redirect(skb, dev_net(skb->dev), t->dev->ifindex, 0, |
159 | IPPROTO_IPIP, 0); |
160 | err = 0; |
161 | goto out; |
162 | } |
163 | |
164 | if (t->parms.iph.daddr == 0) |
165 | goto out; |
166 | |
167 | err = 0; |
168 | if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED) |
169 | goto out; |
170 | |
171 | if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO)) |
172 | t->err_count++; |
173 | else |
174 | t->err_count = 1; |
175 | t->err_time = jiffies; |
176 | |
177 | out: |
178 | return err; |
179 | } |
180 | |
181 | static const struct tnl_ptk_info tpi = { |
182 | /* no tunnel info required for ipip. */ |
183 | .proto = htons(ETH_P_IP), |
184 | }; |
185 | |
186 | static int ipip_rcv(struct sk_buff *skb) |
187 | { |
188 | struct net *net = dev_net(skb->dev); |
189 | struct ip_tunnel_net *itn = net_generic(net, ipip_net_id); |
190 | struct ip_tunnel *tunnel; |
191 | const struct iphdr *iph; |
192 | |
193 | iph = ip_hdr(skb); |
194 | tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, |
195 | iph->saddr, iph->daddr, 0); |
196 | if (tunnel) { |
197 | if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) |
198 | goto drop; |
199 | if (iptunnel_pull_header(skb, 0, tpi.proto)) |
200 | goto drop; |
201 | return ip_tunnel_rcv(tunnel, skb, &tpi, log_ecn_error); |
202 | } |
203 | |
204 | return -1; |
205 | |
206 | drop: |
207 | kfree_skb(skb); |
208 | return 0; |
209 | } |
210 | |
211 | /* |
212 | * This function assumes it is being called from dev_queue_xmit() |
213 | * and that skb is filled properly by that function. |
214 | */ |
215 | static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) |
216 | { |
217 | struct ip_tunnel *tunnel = netdev_priv(dev); |
218 | const struct iphdr *tiph = &tunnel->parms.iph; |
219 | |
220 | if (unlikely(skb->protocol != htons(ETH_P_IP))) |
221 | goto tx_error; |
222 | |
223 | skb = iptunnel_handle_offloads(skb, false, SKB_GSO_IPIP); |
224 | if (IS_ERR(skb)) |
225 | goto out; |
226 | |
227 | ip_tunnel_xmit(skb, dev, tiph, tiph->protocol); |
228 | return NETDEV_TX_OK; |
229 | |
230 | tx_error: |
231 | kfree_skb(skb); |
232 | out: |
233 | dev->stats.tx_errors++; |
234 | return NETDEV_TX_OK; |
235 | } |
236 | |
237 | static int |
238 | ipip_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) |
239 | { |
240 | int err = 0; |
241 | struct ip_tunnel_parm p; |
242 | |
243 | if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) |
244 | return -EFAULT; |
245 | |
246 | if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) { |
247 | if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP || |
248 | p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF))) |
249 | return -EINVAL; |
250 | } |
251 | |
252 | p.i_key = p.o_key = p.i_flags = p.o_flags = 0; |
253 | if (p.iph.ttl) |
254 | p.iph.frag_off |= htons(IP_DF); |
255 | |
256 | err = ip_tunnel_ioctl(dev, &p, cmd); |
257 | if (err) |
258 | return err; |
259 | |
260 | if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) |
261 | return -EFAULT; |
262 | |
263 | return 0; |
264 | } |
265 | |
266 | static const struct net_device_ops ipip_netdev_ops = { |
267 | .ndo_init = ipip_tunnel_init, |
268 | .ndo_uninit = ip_tunnel_uninit, |
269 | .ndo_start_xmit = ipip_tunnel_xmit, |
270 | .ndo_do_ioctl = ipip_tunnel_ioctl, |
271 | .ndo_change_mtu = ip_tunnel_change_mtu, |
272 | .ndo_get_stats64 = ip_tunnel_get_stats64, |
273 | }; |
274 | |
275 | #define IPIP_FEATURES (NETIF_F_SG | \ |
276 | NETIF_F_FRAGLIST | \ |
277 | NETIF_F_HIGHDMA | \ |
278 | NETIF_F_GSO_SOFTWARE | \ |
279 | NETIF_F_HW_CSUM) |
280 | |
281 | static void ipip_tunnel_setup(struct net_device *dev) |
282 | { |
283 | dev->netdev_ops = &ipip_netdev_ops; |
284 | |
285 | dev->type = ARPHRD_TUNNEL; |
286 | dev->flags = IFF_NOARP; |
287 | dev->iflink = 0; |
288 | dev->addr_len = 4; |
289 | dev->features |= NETIF_F_LLTX; |
290 | dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; |
291 | |
292 | dev->features |= IPIP_FEATURES; |
293 | dev->hw_features |= IPIP_FEATURES; |
294 | ip_tunnel_setup(dev, ipip_net_id); |
295 | } |
296 | |
297 | static int ipip_tunnel_init(struct net_device *dev) |
298 | { |
299 | struct ip_tunnel *tunnel = netdev_priv(dev); |
300 | |
301 | memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4); |
302 | memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4); |
303 | |
304 | tunnel->hlen = 0; |
305 | tunnel->parms.iph.protocol = IPPROTO_IPIP; |
306 | return ip_tunnel_init(dev); |
307 | } |
308 | |
309 | static void ipip_netlink_parms(struct nlattr *data[], |
310 | struct ip_tunnel_parm *parms) |
311 | { |
312 | memset(parms, 0, sizeof(*parms)); |
313 | |
314 | parms->iph.version = 4; |
315 | parms->iph.protocol = IPPROTO_IPIP; |
316 | parms->iph.ihl = 5; |
317 | |
318 | if (!data) |
319 | return; |
320 | |
321 | if (data[IFLA_IPTUN_LINK]) |
322 | parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]); |
323 | |
324 | if (data[IFLA_IPTUN_LOCAL]) |
325 | parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]); |
326 | |
327 | if (data[IFLA_IPTUN_REMOTE]) |
328 | parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]); |
329 | |
330 | if (data[IFLA_IPTUN_TTL]) { |
331 | parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]); |
332 | if (parms->iph.ttl) |
333 | parms->iph.frag_off = htons(IP_DF); |
334 | } |
335 | |
336 | if (data[IFLA_IPTUN_TOS]) |
337 | parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]); |
338 | |
339 | if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC])) |
340 | parms->iph.frag_off = htons(IP_DF); |
341 | } |
342 | |
343 | static int ipip_newlink(struct net *src_net, struct net_device *dev, |
344 | struct nlattr *tb[], struct nlattr *data[]) |
345 | { |
346 | struct ip_tunnel_parm p; |
347 | |
348 | ipip_netlink_parms(data, &p); |
349 | return ip_tunnel_newlink(dev, tb, &p); |
350 | } |
351 | |
352 | static int ipip_changelink(struct net_device *dev, struct nlattr *tb[], |
353 | struct nlattr *data[]) |
354 | { |
355 | struct ip_tunnel_parm p; |
356 | |
357 | ipip_netlink_parms(data, &p); |
358 | |
359 | if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) || |
360 | (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr)) |
361 | return -EINVAL; |
362 | |
363 | return ip_tunnel_changelink(dev, tb, &p); |
364 | } |
365 | |
366 | static size_t ipip_get_size(const struct net_device *dev) |
367 | { |
368 | return |
369 | /* IFLA_IPTUN_LINK */ |
370 | nla_total_size(4) + |
371 | /* IFLA_IPTUN_LOCAL */ |
372 | nla_total_size(4) + |
373 | /* IFLA_IPTUN_REMOTE */ |
374 | nla_total_size(4) + |
375 | /* IFLA_IPTUN_TTL */ |
376 | nla_total_size(1) + |
377 | /* IFLA_IPTUN_TOS */ |
378 | nla_total_size(1) + |
379 | /* IFLA_IPTUN_PMTUDISC */ |
380 | nla_total_size(1) + |
381 | 0; |
382 | } |
383 | |
384 | static int ipip_fill_info(struct sk_buff *skb, const struct net_device *dev) |
385 | { |
386 | struct ip_tunnel *tunnel = netdev_priv(dev); |
387 | struct ip_tunnel_parm *parm = &tunnel->parms; |
388 | |
389 | if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) || |
390 | nla_put_be32(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) || |
391 | nla_put_be32(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) || |
392 | nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) || |
393 | nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) || |
394 | nla_put_u8(skb, IFLA_IPTUN_PMTUDISC, |
395 | !!(parm->iph.frag_off & htons(IP_DF)))) |
396 | goto nla_put_failure; |
397 | return 0; |
398 | |
399 | nla_put_failure: |
400 | return -EMSGSIZE; |
401 | } |
402 | |
403 | static const struct nla_policy ipip_policy[IFLA_IPTUN_MAX + 1] = { |
404 | [IFLA_IPTUN_LINK] = { .type = NLA_U32 }, |
405 | [IFLA_IPTUN_LOCAL] = { .type = NLA_U32 }, |
406 | [IFLA_IPTUN_REMOTE] = { .type = NLA_U32 }, |
407 | [IFLA_IPTUN_TTL] = { .type = NLA_U8 }, |
408 | [IFLA_IPTUN_TOS] = { .type = NLA_U8 }, |
409 | [IFLA_IPTUN_PMTUDISC] = { .type = NLA_U8 }, |
410 | }; |
411 | |
412 | static struct rtnl_link_ops ipip_link_ops __read_mostly = { |
413 | .kind = "ipip", |
414 | .maxtype = IFLA_IPTUN_MAX, |
415 | .policy = ipip_policy, |
416 | .priv_size = sizeof(struct ip_tunnel), |
417 | .setup = ipip_tunnel_setup, |
418 | .newlink = ipip_newlink, |
419 | .changelink = ipip_changelink, |
420 | .dellink = ip_tunnel_dellink, |
421 | .get_size = ipip_get_size, |
422 | .fill_info = ipip_fill_info, |
423 | }; |
424 | |
425 | static struct xfrm_tunnel ipip_handler __read_mostly = { |
426 | .handler = ipip_rcv, |
427 | .err_handler = ipip_err, |
428 | .priority = 1, |
429 | }; |
430 | |
431 | static int __net_init ipip_init_net(struct net *net) |
432 | { |
433 | return ip_tunnel_init_net(net, ipip_net_id, &ipip_link_ops, "tunl0"); |
434 | } |
435 | |
436 | static void __net_exit ipip_exit_net(struct net *net) |
437 | { |
438 | struct ip_tunnel_net *itn = net_generic(net, ipip_net_id); |
439 | ip_tunnel_delete_net(itn, &ipip_link_ops); |
440 | } |
441 | |
442 | static struct pernet_operations ipip_net_ops = { |
443 | .init = ipip_init_net, |
444 | .exit = ipip_exit_net, |
445 | .id = &ipip_net_id, |
446 | .size = sizeof(struct ip_tunnel_net), |
447 | }; |
448 | |
449 | static int __init ipip_init(void) |
450 | { |
451 | int err; |
452 | |
453 | pr_info("ipip: IPv4 over IPv4 tunneling driver\n"); |
454 | |
455 | err = register_pernet_device(&ipip_net_ops); |
456 | if (err < 0) |
457 | return err; |
458 | err = xfrm4_tunnel_register(&ipip_handler, AF_INET); |
459 | if (err < 0) { |
460 | pr_info("%s: can't register tunnel\n", __func__); |
461 | goto xfrm_tunnel_failed; |
462 | } |
463 | err = rtnl_link_register(&ipip_link_ops); |
464 | if (err < 0) |
465 | goto rtnl_link_failed; |
466 | |
467 | out: |
468 | return err; |
469 | |
470 | rtnl_link_failed: |
471 | xfrm4_tunnel_deregister(&ipip_handler, AF_INET); |
472 | xfrm_tunnel_failed: |
473 | unregister_pernet_device(&ipip_net_ops); |
474 | goto out; |
475 | } |
476 | |
477 | static void __exit ipip_fini(void) |
478 | { |
479 | rtnl_link_unregister(&ipip_link_ops); |
480 | if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET)) |
481 | pr_info("%s: can't deregister tunnel\n", __func__); |
482 | |
483 | unregister_pernet_device(&ipip_net_ops); |
484 | } |
485 | |
486 | module_init(ipip_init); |
487 | module_exit(ipip_fini); |
488 | MODULE_LICENSE("GPL"); |
489 | MODULE_ALIAS_NETDEV("tunl0"); |
490 |
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