xref: /openbmc/linux/net/ipv4/ip_tunnel_core.c (revision 63d008a4)
1 /*
2  * Copyright (c) 2013 Nicira, Inc.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of version 2 of the GNU General Public
6  * License as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful, but
9  * WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program; if not, write to the Free Software
15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
16  * 02110-1301, USA
17  */
18 
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/skbuff.h>
24 #include <linux/netdevice.h>
25 #include <linux/in.h>
26 #include <linux/if_arp.h>
27 #include <linux/mroute.h>
28 #include <linux/init.h>
29 #include <linux/in6.h>
30 #include <linux/inetdevice.h>
31 #include <linux/netfilter_ipv4.h>
32 #include <linux/etherdevice.h>
33 #include <linux/if_ether.h>
34 #include <linux/if_vlan.h>
35 #include <linux/static_key.h>
36 
37 #include <net/ip.h>
38 #include <net/icmp.h>
39 #include <net/protocol.h>
40 #include <net/ip_tunnels.h>
41 #include <net/arp.h>
42 #include <net/checksum.h>
43 #include <net/dsfield.h>
44 #include <net/inet_ecn.h>
45 #include <net/xfrm.h>
46 #include <net/net_namespace.h>
47 #include <net/netns/generic.h>
48 #include <net/rtnetlink.h>
49 #include <net/dst_metadata.h>
50 
51 int iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
52 		  __be32 src, __be32 dst, __u8 proto,
53 		  __u8 tos, __u8 ttl, __be16 df, bool xnet)
54 {
55 	int pkt_len = skb->len - skb_inner_network_offset(skb);
56 	struct iphdr *iph;
57 	int err;
58 
59 	skb_scrub_packet(skb, xnet);
60 
61 	skb_clear_hash(skb);
62 	skb_dst_set(skb, &rt->dst);
63 	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
64 
65 	/* Push down and install the IP header. */
66 	skb_push(skb, sizeof(struct iphdr));
67 	skb_reset_network_header(skb);
68 
69 	iph = ip_hdr(skb);
70 
71 	iph->version	=	4;
72 	iph->ihl	=	sizeof(struct iphdr) >> 2;
73 	iph->frag_off	=	df;
74 	iph->protocol	=	proto;
75 	iph->tos	=	tos;
76 	iph->daddr	=	dst;
77 	iph->saddr	=	src;
78 	iph->ttl	=	ttl;
79 	__ip_select_ident(dev_net(rt->dst.dev), iph,
80 			  skb_shinfo(skb)->gso_segs ?: 1);
81 
82 	err = ip_local_out_sk(sk, skb);
83 	if (unlikely(net_xmit_eval(err)))
84 		pkt_len = 0;
85 	return pkt_len;
86 }
87 EXPORT_SYMBOL_GPL(iptunnel_xmit);
88 
89 int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto)
90 {
91 	if (unlikely(!pskb_may_pull(skb, hdr_len)))
92 		return -ENOMEM;
93 
94 	skb_pull_rcsum(skb, hdr_len);
95 
96 	if (inner_proto == htons(ETH_P_TEB)) {
97 		struct ethhdr *eh;
98 
99 		if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
100 			return -ENOMEM;
101 
102 		eh = (struct ethhdr *)skb->data;
103 		if (likely(eth_proto_is_802_3(eh->h_proto)))
104 			skb->protocol = eh->h_proto;
105 		else
106 			skb->protocol = htons(ETH_P_802_2);
107 
108 	} else {
109 		skb->protocol = inner_proto;
110 	}
111 
112 	nf_reset(skb);
113 	secpath_reset(skb);
114 	skb_clear_hash_if_not_l4(skb);
115 	skb_dst_drop(skb);
116 	skb->vlan_tci = 0;
117 	skb_set_queue_mapping(skb, 0);
118 	skb->pkt_type = PACKET_HOST;
119 	return 0;
120 }
121 EXPORT_SYMBOL_GPL(iptunnel_pull_header);
122 
123 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
124 					     gfp_t flags)
125 {
126 	struct metadata_dst *res;
127 	struct ip_tunnel_info *dst, *src;
128 
129 	if (!md || md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
130 		return NULL;
131 
132 	res = metadata_dst_alloc(0, flags);
133 	if (!res)
134 		return NULL;
135 
136 	dst = &res->u.tun_info;
137 	src = &md->u.tun_info;
138 	dst->key.tun_id = src->key.tun_id;
139 	if (src->mode & IP_TUNNEL_INFO_IPV6)
140 		memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
141 		       sizeof(struct in6_addr));
142 	else
143 		dst->key.u.ipv4.dst = src->key.u.ipv4.src;
144 	dst->mode = src->mode | IP_TUNNEL_INFO_TX;
145 
146 	return res;
147 }
148 EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
149 
150 struct sk_buff *iptunnel_handle_offloads(struct sk_buff *skb,
151 					 bool csum_help,
152 					 int gso_type_mask)
153 {
154 	int err;
155 
156 	if (likely(!skb->encapsulation)) {
157 		skb_reset_inner_headers(skb);
158 		skb->encapsulation = 1;
159 	}
160 
161 	if (skb_is_gso(skb)) {
162 		err = skb_unclone(skb, GFP_ATOMIC);
163 		if (unlikely(err))
164 			goto error;
165 		skb_shinfo(skb)->gso_type |= gso_type_mask;
166 		return skb;
167 	}
168 
169 	/* If packet is not gso and we are resolving any partial checksum,
170 	 * clear encapsulation flag. This allows setting CHECKSUM_PARTIAL
171 	 * on the outer header without confusing devices that implement
172 	 * NETIF_F_IP_CSUM with encapsulation.
173 	 */
174 	if (csum_help)
175 		skb->encapsulation = 0;
176 
177 	if (skb->ip_summed == CHECKSUM_PARTIAL && csum_help) {
178 		err = skb_checksum_help(skb);
179 		if (unlikely(err))
180 			goto error;
181 	} else if (skb->ip_summed != CHECKSUM_PARTIAL)
182 		skb->ip_summed = CHECKSUM_NONE;
183 
184 	return skb;
185 error:
186 	kfree_skb(skb);
187 	return ERR_PTR(err);
188 }
189 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
190 
191 /* Often modified stats are per cpu, other are shared (netdev->stats) */
192 struct rtnl_link_stats64 *ip_tunnel_get_stats64(struct net_device *dev,
193 						struct rtnl_link_stats64 *tot)
194 {
195 	int i;
196 
197 	netdev_stats_to_stats64(tot, &dev->stats);
198 
199 	for_each_possible_cpu(i) {
200 		const struct pcpu_sw_netstats *tstats =
201 						   per_cpu_ptr(dev->tstats, i);
202 		u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
203 		unsigned int start;
204 
205 		do {
206 			start = u64_stats_fetch_begin_irq(&tstats->syncp);
207 			rx_packets = tstats->rx_packets;
208 			tx_packets = tstats->tx_packets;
209 			rx_bytes = tstats->rx_bytes;
210 			tx_bytes = tstats->tx_bytes;
211 		} while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
212 
213 		tot->rx_packets += rx_packets;
214 		tot->tx_packets += tx_packets;
215 		tot->rx_bytes   += rx_bytes;
216 		tot->tx_bytes   += tx_bytes;
217 	}
218 
219 	return tot;
220 }
221 EXPORT_SYMBOL_GPL(ip_tunnel_get_stats64);
222 
223 static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
224 	[LWTUNNEL_IP_ID]	= { .type = NLA_U64 },
225 	[LWTUNNEL_IP_DST]	= { .type = NLA_U32 },
226 	[LWTUNNEL_IP_SRC]	= { .type = NLA_U32 },
227 	[LWTUNNEL_IP_TTL]	= { .type = NLA_U8 },
228 	[LWTUNNEL_IP_TOS]	= { .type = NLA_U8 },
229 	[LWTUNNEL_IP_SPORT]	= { .type = NLA_U16 },
230 	[LWTUNNEL_IP_DPORT]	= { .type = NLA_U16 },
231 	[LWTUNNEL_IP_FLAGS]	= { .type = NLA_U16 },
232 };
233 
234 static int ip_tun_build_state(struct net_device *dev, struct nlattr *attr,
235 			      unsigned int family, const void *cfg,
236 			      struct lwtunnel_state **ts)
237 {
238 	struct ip_tunnel_info *tun_info;
239 	struct lwtunnel_state *new_state;
240 	struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
241 	int err;
242 
243 	err = nla_parse_nested(tb, LWTUNNEL_IP_MAX, attr, ip_tun_policy);
244 	if (err < 0)
245 		return err;
246 
247 	new_state = lwtunnel_state_alloc(sizeof(*tun_info));
248 	if (!new_state)
249 		return -ENOMEM;
250 
251 	new_state->type = LWTUNNEL_ENCAP_IP;
252 
253 	tun_info = lwt_tun_info(new_state);
254 
255 	if (tb[LWTUNNEL_IP_ID])
256 		tun_info->key.tun_id = nla_get_u64(tb[LWTUNNEL_IP_ID]);
257 
258 	if (tb[LWTUNNEL_IP_DST])
259 		tun_info->key.u.ipv4.dst = nla_get_be32(tb[LWTUNNEL_IP_DST]);
260 
261 	if (tb[LWTUNNEL_IP_SRC])
262 		tun_info->key.u.ipv4.src = nla_get_be32(tb[LWTUNNEL_IP_SRC]);
263 
264 	if (tb[LWTUNNEL_IP_TTL])
265 		tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
266 
267 	if (tb[LWTUNNEL_IP_TOS])
268 		tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
269 
270 	if (tb[LWTUNNEL_IP_SPORT])
271 		tun_info->key.tp_src = nla_get_be16(tb[LWTUNNEL_IP_SPORT]);
272 
273 	if (tb[LWTUNNEL_IP_DPORT])
274 		tun_info->key.tp_dst = nla_get_be16(tb[LWTUNNEL_IP_DPORT]);
275 
276 	if (tb[LWTUNNEL_IP_FLAGS])
277 		tun_info->key.tun_flags = nla_get_u16(tb[LWTUNNEL_IP_FLAGS]);
278 
279 	tun_info->mode = IP_TUNNEL_INFO_TX;
280 	tun_info->options_len = 0;
281 
282 	*ts = new_state;
283 
284 	return 0;
285 }
286 
287 static int ip_tun_fill_encap_info(struct sk_buff *skb,
288 				  struct lwtunnel_state *lwtstate)
289 {
290 	struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
291 
292 	if (nla_put_u64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id) ||
293 	    nla_put_be32(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
294 	    nla_put_be32(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
295 	    nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
296 	    nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
297 	    nla_put_u16(skb, LWTUNNEL_IP_SPORT, tun_info->key.tp_src) ||
298 	    nla_put_u16(skb, LWTUNNEL_IP_DPORT, tun_info->key.tp_dst) ||
299 	    nla_put_u16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags))
300 		return -ENOMEM;
301 
302 	return 0;
303 }
304 
305 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
306 {
307 	return nla_total_size(8)	/* LWTUNNEL_IP_ID */
308 		+ nla_total_size(4)	/* LWTUNNEL_IP_DST */
309 		+ nla_total_size(4)	/* LWTUNNEL_IP_SRC */
310 		+ nla_total_size(1)	/* LWTUNNEL_IP_TOS */
311 		+ nla_total_size(1)	/* LWTUNNEL_IP_TTL */
312 		+ nla_total_size(2)	/* LWTUNNEL_IP_SPORT */
313 		+ nla_total_size(2)	/* LWTUNNEL_IP_DPORT */
314 		+ nla_total_size(2);	/* LWTUNNEL_IP_FLAGS */
315 }
316 
317 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
318 {
319 	return memcmp(lwt_tun_info(a), lwt_tun_info(b),
320 		      sizeof(struct ip_tunnel_info));
321 }
322 
323 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
324 	.build_state = ip_tun_build_state,
325 	.fill_encap = ip_tun_fill_encap_info,
326 	.get_encap_size = ip_tun_encap_nlsize,
327 	.cmp_encap = ip_tun_cmp_encap,
328 };
329 
330 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
331 	[LWTUNNEL_IP6_ID]		= { .type = NLA_U64 },
332 	[LWTUNNEL_IP6_DST]		= { .len = sizeof(struct in6_addr) },
333 	[LWTUNNEL_IP6_SRC]		= { .len = sizeof(struct in6_addr) },
334 	[LWTUNNEL_IP6_HOPLIMIT]		= { .type = NLA_U8 },
335 	[LWTUNNEL_IP6_TC]		= { .type = NLA_U8 },
336 	[LWTUNNEL_IP6_SPORT]		= { .type = NLA_U16 },
337 	[LWTUNNEL_IP6_DPORT]		= { .type = NLA_U16 },
338 	[LWTUNNEL_IP6_FLAGS]		= { .type = NLA_U16 },
339 };
340 
341 static int ip6_tun_build_state(struct net_device *dev, struct nlattr *attr,
342 			       unsigned int family, const void *cfg,
343 			       struct lwtunnel_state **ts)
344 {
345 	struct ip_tunnel_info *tun_info;
346 	struct lwtunnel_state *new_state;
347 	struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
348 	int err;
349 
350 	err = nla_parse_nested(tb, LWTUNNEL_IP6_MAX, attr, ip6_tun_policy);
351 	if (err < 0)
352 		return err;
353 
354 	new_state = lwtunnel_state_alloc(sizeof(*tun_info));
355 	if (!new_state)
356 		return -ENOMEM;
357 
358 	new_state->type = LWTUNNEL_ENCAP_IP6;
359 
360 	tun_info = lwt_tun_info(new_state);
361 
362 	if (tb[LWTUNNEL_IP6_ID])
363 		tun_info->key.tun_id = nla_get_u64(tb[LWTUNNEL_IP6_ID]);
364 
365 	if (tb[LWTUNNEL_IP6_DST])
366 		tun_info->key.u.ipv6.dst = nla_get_in6_addr(tb[LWTUNNEL_IP6_DST]);
367 
368 	if (tb[LWTUNNEL_IP6_SRC])
369 		tun_info->key.u.ipv6.src = nla_get_in6_addr(tb[LWTUNNEL_IP6_SRC]);
370 
371 	if (tb[LWTUNNEL_IP6_HOPLIMIT])
372 		tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP6_HOPLIMIT]);
373 
374 	if (tb[LWTUNNEL_IP6_TC])
375 		tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
376 
377 	if (tb[LWTUNNEL_IP6_SPORT])
378 		tun_info->key.tp_src = nla_get_be16(tb[LWTUNNEL_IP6_SPORT]);
379 
380 	if (tb[LWTUNNEL_IP6_DPORT])
381 		tun_info->key.tp_dst = nla_get_be16(tb[LWTUNNEL_IP6_DPORT]);
382 
383 	if (tb[LWTUNNEL_IP6_FLAGS])
384 		tun_info->key.tun_flags = nla_get_u16(tb[LWTUNNEL_IP6_FLAGS]);
385 
386 	tun_info->mode = IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_IPV6;
387 	tun_info->options_len = 0;
388 
389 	*ts = new_state;
390 
391 	return 0;
392 }
393 
394 static int ip6_tun_fill_encap_info(struct sk_buff *skb,
395 				   struct lwtunnel_state *lwtstate)
396 {
397 	struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
398 
399 	if (nla_put_u64(skb, LWTUNNEL_IP6_ID, tun_info->key.tun_id) ||
400 	    nla_put_in6_addr(skb, LWTUNNEL_IP6_DST, &tun_info->key.u.ipv6.dst) ||
401 	    nla_put_in6_addr(skb, LWTUNNEL_IP6_SRC, &tun_info->key.u.ipv6.src) ||
402 	    nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.tos) ||
403 	    nla_put_u8(skb, LWTUNNEL_IP6_TC, tun_info->key.ttl) ||
404 	    nla_put_u16(skb, LWTUNNEL_IP6_SPORT, tun_info->key.tp_src) ||
405 	    nla_put_u16(skb, LWTUNNEL_IP6_DPORT, tun_info->key.tp_dst) ||
406 	    nla_put_u16(skb, LWTUNNEL_IP6_FLAGS, tun_info->key.tun_flags))
407 		return -ENOMEM;
408 
409 	return 0;
410 }
411 
412 static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
413 {
414 	return nla_total_size(8)	/* LWTUNNEL_IP6_ID */
415 		+ nla_total_size(16)	/* LWTUNNEL_IP6_DST */
416 		+ nla_total_size(16)	/* LWTUNNEL_IP6_SRC */
417 		+ nla_total_size(1)	/* LWTUNNEL_IP6_HOPLIMIT */
418 		+ nla_total_size(1)	/* LWTUNNEL_IP6_TC */
419 		+ nla_total_size(2)	/* LWTUNNEL_IP6_SPORT */
420 		+ nla_total_size(2)	/* LWTUNNEL_IP6_DPORT */
421 		+ nla_total_size(2);	/* LWTUNNEL_IP6_FLAGS */
422 }
423 
424 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {
425 	.build_state = ip6_tun_build_state,
426 	.fill_encap = ip6_tun_fill_encap_info,
427 	.get_encap_size = ip6_tun_encap_nlsize,
428 	.cmp_encap = ip_tun_cmp_encap,
429 };
430 
431 void __init ip_tunnel_core_init(void)
432 {
433 	lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
434 	lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
435 }
436 
437 struct static_key ip_tunnel_metadata_cnt = STATIC_KEY_INIT_FALSE;
438 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
439 
440 void ip_tunnel_need_metadata(void)
441 {
442 	static_key_slow_inc(&ip_tunnel_metadata_cnt);
443 }
444 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
445 
446 void ip_tunnel_unneed_metadata(void)
447 {
448 	static_key_slow_dec(&ip_tunnel_metadata_cnt);
449 }
450 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);
451