30c1c264bdfc26ffb32e770ab13df7adb24b9da3
[muen/linux.git] / net / ipv4 / ip_tunnel_core.c
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/init.h>
28 #include <linux/in6.h>
29 #include <linux/inetdevice.h>
30 #include <linux/netfilter_ipv4.h>
31 #include <linux/etherdevice.h>
32 #include <linux/if_ether.h>
33 #include <linux/if_vlan.h>
34 #include <linux/static_key.h>
35
36 #include <net/ip.h>
37 #include <net/icmp.h>
38 #include <net/protocol.h>
39 #include <net/ip_tunnels.h>
40 #include <net/ip6_tunnel.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 const struct ip_tunnel_encap_ops __rcu *
52                 iptun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
53 EXPORT_SYMBOL(iptun_encaps);
54
55 const struct ip6_tnl_encap_ops __rcu *
56                 ip6tun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
57 EXPORT_SYMBOL(ip6tun_encaps);
58
59 void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
60                    __be32 src, __be32 dst, __u8 proto,
61                    __u8 tos, __u8 ttl, __be16 df, bool xnet)
62 {
63         int pkt_len = skb->len - skb_inner_network_offset(skb);
64         struct net *net = dev_net(rt->dst.dev);
65         struct net_device *dev = skb->dev;
66         struct iphdr *iph;
67         int err;
68
69         skb_scrub_packet(skb, xnet);
70
71         skb_clear_hash_if_not_l4(skb);
72         skb_dst_set(skb, &rt->dst);
73         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
74
75         /* Push down and install the IP header. */
76         skb_push(skb, sizeof(struct iphdr));
77         skb_reset_network_header(skb);
78
79         iph = ip_hdr(skb);
80
81         iph->version    =       4;
82         iph->ihl        =       sizeof(struct iphdr) >> 2;
83         iph->frag_off   =       ip_mtu_locked(&rt->dst) ? 0 : df;
84         iph->protocol   =       proto;
85         iph->tos        =       tos;
86         iph->daddr      =       dst;
87         iph->saddr      =       src;
88         iph->ttl        =       ttl;
89         __ip_select_ident(net, iph, skb_shinfo(skb)->gso_segs ?: 1);
90
91         err = ip_local_out(net, sk, skb);
92         if (unlikely(net_xmit_eval(err)))
93                 pkt_len = 0;
94         iptunnel_xmit_stats(dev, pkt_len);
95 }
96 EXPORT_SYMBOL_GPL(iptunnel_xmit);
97
98 int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
99                            __be16 inner_proto, bool raw_proto, bool xnet)
100 {
101         if (unlikely(!pskb_may_pull(skb, hdr_len)))
102                 return -ENOMEM;
103
104         skb_pull_rcsum(skb, hdr_len);
105
106         if (!raw_proto && inner_proto == htons(ETH_P_TEB)) {
107                 struct ethhdr *eh;
108
109                 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
110                         return -ENOMEM;
111
112                 eh = (struct ethhdr *)skb->data;
113                 if (likely(eth_proto_is_802_3(eh->h_proto)))
114                         skb->protocol = eh->h_proto;
115                 else
116                         skb->protocol = htons(ETH_P_802_2);
117
118         } else {
119                 skb->protocol = inner_proto;
120         }
121
122         skb_clear_hash_if_not_l4(skb);
123         __vlan_hwaccel_clear_tag(skb);
124         skb_set_queue_mapping(skb, 0);
125         skb_scrub_packet(skb, xnet);
126
127         return iptunnel_pull_offloads(skb);
128 }
129 EXPORT_SYMBOL_GPL(__iptunnel_pull_header);
130
131 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
132                                              gfp_t flags)
133 {
134         struct metadata_dst *res;
135         struct ip_tunnel_info *dst, *src;
136
137         if (!md || md->type != METADATA_IP_TUNNEL ||
138             md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
139
140                 return NULL;
141
142         res = metadata_dst_alloc(0, METADATA_IP_TUNNEL, flags);
143         if (!res)
144                 return NULL;
145
146         dst = &res->u.tun_info;
147         src = &md->u.tun_info;
148         dst->key.tun_id = src->key.tun_id;
149         if (src->mode & IP_TUNNEL_INFO_IPV6)
150                 memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
151                        sizeof(struct in6_addr));
152         else
153                 dst->key.u.ipv4.dst = src->key.u.ipv4.src;
154         dst->key.tun_flags = src->key.tun_flags;
155         dst->mode = src->mode | IP_TUNNEL_INFO_TX;
156
157         return res;
158 }
159 EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
160
161 int iptunnel_handle_offloads(struct sk_buff *skb,
162                              int gso_type_mask)
163 {
164         int err;
165
166         if (likely(!skb->encapsulation)) {
167                 skb_reset_inner_headers(skb);
168                 skb->encapsulation = 1;
169         }
170
171         if (skb_is_gso(skb)) {
172                 err = skb_header_unclone(skb, GFP_ATOMIC);
173                 if (unlikely(err))
174                         return err;
175                 skb_shinfo(skb)->gso_type |= gso_type_mask;
176                 return 0;
177         }
178
179         if (skb->ip_summed != CHECKSUM_PARTIAL) {
180                 skb->ip_summed = CHECKSUM_NONE;
181                 /* We clear encapsulation here to prevent badly-written
182                  * drivers potentially deciding to offload an inner checksum
183                  * if we set CHECKSUM_PARTIAL on the outer header.
184                  * This should go away when the drivers are all fixed.
185                  */
186                 skb->encapsulation = 0;
187         }
188
189         return 0;
190 }
191 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
192
193 /* Often modified stats are per cpu, other are shared (netdev->stats) */
194 void ip_tunnel_get_stats64(struct net_device *dev,
195                            struct rtnl_link_stats64 *tot)
196 {
197         int i;
198
199         netdev_stats_to_stats64(tot, &dev->stats);
200
201         for_each_possible_cpu(i) {
202                 const struct pcpu_sw_netstats *tstats =
203                                                    per_cpu_ptr(dev->tstats, i);
204                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
205                 unsigned int start;
206
207                 do {
208                         start = u64_stats_fetch_begin_irq(&tstats->syncp);
209                         rx_packets = tstats->rx_packets;
210                         tx_packets = tstats->tx_packets;
211                         rx_bytes = tstats->rx_bytes;
212                         tx_bytes = tstats->tx_bytes;
213                 } while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
214
215                 tot->rx_packets += rx_packets;
216                 tot->tx_packets += tx_packets;
217                 tot->rx_bytes   += rx_bytes;
218                 tot->tx_bytes   += tx_bytes;
219         }
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_FLAGS]     = { .type = NLA_U16 },
230 };
231
232 static int ip_tun_build_state(struct nlattr *attr,
233                               unsigned int family, const void *cfg,
234                               struct lwtunnel_state **ts,
235                               struct netlink_ext_ack *extack)
236 {
237         struct ip_tunnel_info *tun_info;
238         struct lwtunnel_state *new_state;
239         struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
240         int err;
241
242         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP_MAX, attr,
243                                           ip_tun_policy, extack);
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 #ifdef CONFIG_DST_CACHE
256         err = dst_cache_init(&tun_info->dst_cache, GFP_KERNEL);
257         if (err) {
258                 lwtstate_free(new_state);
259                 return err;
260         }
261 #endif
262
263         if (tb[LWTUNNEL_IP_ID])
264                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
265
266         if (tb[LWTUNNEL_IP_DST])
267                 tun_info->key.u.ipv4.dst = nla_get_in_addr(tb[LWTUNNEL_IP_DST]);
268
269         if (tb[LWTUNNEL_IP_SRC])
270                 tun_info->key.u.ipv4.src = nla_get_in_addr(tb[LWTUNNEL_IP_SRC]);
271
272         if (tb[LWTUNNEL_IP_TTL])
273                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
274
275         if (tb[LWTUNNEL_IP_TOS])
276                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
277
278         if (tb[LWTUNNEL_IP_FLAGS])
279                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP_FLAGS]);
280
281         tun_info->mode = IP_TUNNEL_INFO_TX;
282         tun_info->options_len = 0;
283
284         *ts = new_state;
285
286         return 0;
287 }
288
289 static void ip_tun_destroy_state(struct lwtunnel_state *lwtstate)
290 {
291 #ifdef CONFIG_DST_CACHE
292         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
293
294         dst_cache_destroy(&tun_info->dst_cache);
295 #endif
296 }
297
298 static int ip_tun_fill_encap_info(struct sk_buff *skb,
299                                   struct lwtunnel_state *lwtstate)
300 {
301         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
302
303         if (nla_put_be64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id,
304                          LWTUNNEL_IP_PAD) ||
305             nla_put_in_addr(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
306             nla_put_in_addr(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
307             nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
308             nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
309             nla_put_be16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags))
310                 return -ENOMEM;
311
312         return 0;
313 }
314
315 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
316 {
317         return nla_total_size_64bit(8)  /* LWTUNNEL_IP_ID */
318                 + nla_total_size(4)     /* LWTUNNEL_IP_DST */
319                 + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
320                 + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
321                 + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
322                 + nla_total_size(2);    /* LWTUNNEL_IP_FLAGS */
323 }
324
325 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
326 {
327         return memcmp(lwt_tun_info(a), lwt_tun_info(b),
328                       sizeof(struct ip_tunnel_info));
329 }
330
331 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
332         .build_state = ip_tun_build_state,
333         .destroy_state = ip_tun_destroy_state,
334         .fill_encap = ip_tun_fill_encap_info,
335         .get_encap_size = ip_tun_encap_nlsize,
336         .cmp_encap = ip_tun_cmp_encap,
337         .owner = THIS_MODULE,
338 };
339
340 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
341         [LWTUNNEL_IP6_ID]               = { .type = NLA_U64 },
342         [LWTUNNEL_IP6_DST]              = { .len = sizeof(struct in6_addr) },
343         [LWTUNNEL_IP6_SRC]              = { .len = sizeof(struct in6_addr) },
344         [LWTUNNEL_IP6_HOPLIMIT]         = { .type = NLA_U8 },
345         [LWTUNNEL_IP6_TC]               = { .type = NLA_U8 },
346         [LWTUNNEL_IP6_FLAGS]            = { .type = NLA_U16 },
347 };
348
349 static int ip6_tun_build_state(struct nlattr *attr,
350                                unsigned int family, const void *cfg,
351                                struct lwtunnel_state **ts,
352                                struct netlink_ext_ack *extack)
353 {
354         struct ip_tunnel_info *tun_info;
355         struct lwtunnel_state *new_state;
356         struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
357         int err;
358
359         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP6_MAX, attr,
360                                           ip6_tun_policy, extack);
361         if (err < 0)
362                 return err;
363
364         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
365         if (!new_state)
366                 return -ENOMEM;
367
368         new_state->type = LWTUNNEL_ENCAP_IP6;
369
370         tun_info = lwt_tun_info(new_state);
371
372         if (tb[LWTUNNEL_IP6_ID])
373                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP6_ID]);
374
375         if (tb[LWTUNNEL_IP6_DST])
376                 tun_info->key.u.ipv6.dst = nla_get_in6_addr(tb[LWTUNNEL_IP6_DST]);
377
378         if (tb[LWTUNNEL_IP6_SRC])
379                 tun_info->key.u.ipv6.src = nla_get_in6_addr(tb[LWTUNNEL_IP6_SRC]);
380
381         if (tb[LWTUNNEL_IP6_HOPLIMIT])
382                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP6_HOPLIMIT]);
383
384         if (tb[LWTUNNEL_IP6_TC])
385                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
386
387         if (tb[LWTUNNEL_IP6_FLAGS])
388                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP6_FLAGS]);
389
390         tun_info->mode = IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_IPV6;
391         tun_info->options_len = 0;
392
393         *ts = new_state;
394
395         return 0;
396 }
397
398 static int ip6_tun_fill_encap_info(struct sk_buff *skb,
399                                    struct lwtunnel_state *lwtstate)
400 {
401         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
402
403         if (nla_put_be64(skb, LWTUNNEL_IP6_ID, tun_info->key.tun_id,
404                          LWTUNNEL_IP6_PAD) ||
405             nla_put_in6_addr(skb, LWTUNNEL_IP6_DST, &tun_info->key.u.ipv6.dst) ||
406             nla_put_in6_addr(skb, LWTUNNEL_IP6_SRC, &tun_info->key.u.ipv6.src) ||
407             nla_put_u8(skb, LWTUNNEL_IP6_TC, tun_info->key.tos) ||
408             nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.ttl) ||
409             nla_put_be16(skb, LWTUNNEL_IP6_FLAGS, tun_info->key.tun_flags))
410                 return -ENOMEM;
411
412         return 0;
413 }
414
415 static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
416 {
417         return nla_total_size_64bit(8)  /* LWTUNNEL_IP6_ID */
418                 + nla_total_size(16)    /* LWTUNNEL_IP6_DST */
419                 + nla_total_size(16)    /* LWTUNNEL_IP6_SRC */
420                 + nla_total_size(1)     /* LWTUNNEL_IP6_HOPLIMIT */
421                 + nla_total_size(1)     /* LWTUNNEL_IP6_TC */
422                 + nla_total_size(2);    /* LWTUNNEL_IP6_FLAGS */
423 }
424
425 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {
426         .build_state = ip6_tun_build_state,
427         .fill_encap = ip6_tun_fill_encap_info,
428         .get_encap_size = ip6_tun_encap_nlsize,
429         .cmp_encap = ip_tun_cmp_encap,
430         .owner = THIS_MODULE,
431 };
432
433 void __init ip_tunnel_core_init(void)
434 {
435         /* If you land here, make sure whether increasing ip_tunnel_info's
436          * options_len is a reasonable choice with its usage in front ends
437          * (f.e., it's part of flow keys, etc).
438          */
439         BUILD_BUG_ON(IP_TUNNEL_OPTS_MAX != 255);
440
441         lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
442         lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
443 }
444
445 DEFINE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
446 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
447
448 void ip_tunnel_need_metadata(void)
449 {
450         static_branch_inc(&ip_tunnel_metadata_cnt);
451 }
452 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
453
454 void ip_tunnel_unneed_metadata(void)
455 {
456         static_branch_dec(&ip_tunnel_metadata_cnt);
457 }
458 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);