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1/*
2 * SR-IPv6 implementation
3 *
4 * Author:
5 * David Lebrun <david.lebrun@uclouvain.be>
6 *
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#include <linux/types.h>
15#include <linux/skbuff.h>
16#include <linux/net.h>
17#include <linux/module.h>
18#include <net/ip.h>
19#include <net/ip_tunnels.h>
20#include <net/lwtunnel.h>
21#include <net/netevent.h>
22#include <net/netns/generic.h>
23#include <net/ip6_fib.h>
24#include <net/route.h>
25#include <net/seg6.h>
26#include <linux/seg6.h>
27#include <linux/seg6_iptunnel.h>
28#include <net/addrconf.h>
29#include <net/ip6_route.h>
30#include <net/dst_cache.h>
31#ifdef CONFIG_IPV6_SEG6_HMAC
32#include <net/seg6_hmac.h>
33#endif
34
35struct seg6_lwt {
36 struct dst_cache cache;
37 struct seg6_iptunnel_encap tuninfo[0];
38};
39
40static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt)
41{
42 return (struct seg6_lwt *)lwt->data;
43}
44
45static inline struct seg6_iptunnel_encap *
46seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
47{
48 return seg6_lwt_lwtunnel(lwt)->tuninfo;
49}
50
51static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
52 [SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
53};
54
55static int nla_put_srh(struct sk_buff *skb, int attrtype,
56 struct seg6_iptunnel_encap *tuninfo)
57{
58 struct seg6_iptunnel_encap *data;
59 struct nlattr *nla;
60 int len;
61
62 len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
63
64 nla = nla_reserve(skb, attrtype, len);
65 if (!nla)
66 return -EMSGSIZE;
67
68 data = nla_data(nla);
69 memcpy(data, tuninfo, len);
70
71 return 0;
72}
73
74static void set_tun_src(struct net *net, struct net_device *dev,
75 struct in6_addr *daddr, struct in6_addr *saddr)
76{
77 struct seg6_pernet_data *sdata = seg6_pernet(net);
78 struct in6_addr *tun_src;
79
80 rcu_read_lock();
81
82 tun_src = rcu_dereference(sdata->tun_src);
83
84 if (!ipv6_addr_any(tun_src)) {
85 memcpy(saddr, tun_src, sizeof(struct in6_addr));
86 } else {
87 ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
88 saddr);
89 }
90
91 rcu_read_unlock();
92}
93
94/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
95int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
96{
97 struct dst_entry *dst = skb_dst(skb);
98 struct net *net = dev_net(dst->dev);
99 struct ipv6hdr *hdr, *inner_hdr;
100 struct ipv6_sr_hdr *isrh;
101 int hdrlen, tot_len, err;
102
103 hdrlen = (osrh->hdrlen + 1) << 3;
104 tot_len = hdrlen + sizeof(*hdr);
105
106 err = skb_cow_head(skb, tot_len + skb->mac_len);
107 if (unlikely(err))
108 return err;
109
110 inner_hdr = ipv6_hdr(skb);
111
112 skb_push(skb, tot_len);
113 skb_reset_network_header(skb);
114 skb_mac_header_rebuild(skb);
115 hdr = ipv6_hdr(skb);
116
117 /* inherit tc, flowlabel and hlim
118 * hlim will be decremented in ip6_forward() afterwards and
119 * decapsulation will overwrite inner hlim with outer hlim
120 */
121
122 if (skb->protocol == htons(ETH_P_IPV6)) {
123 ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
124 ip6_flowlabel(inner_hdr));
125 hdr->hop_limit = inner_hdr->hop_limit;
126 } else {
127 ip6_flow_hdr(hdr, 0, 0);
128 hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
129 }
130
131 hdr->nexthdr = NEXTHDR_ROUTING;
132
133 isrh = (void *)hdr + sizeof(*hdr);
134 memcpy(isrh, osrh, hdrlen);
135
136 isrh->nexthdr = proto;
137
138 hdr->daddr = isrh->segments[isrh->first_segment];
139 set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
140
141#ifdef CONFIG_IPV6_SEG6_HMAC
142 if (sr_has_hmac(isrh)) {
143 err = seg6_push_hmac(net, &hdr->saddr, isrh);
144 if (unlikely(err))
145 return err;
146 }
147#endif
148
149 skb_postpush_rcsum(skb, hdr, tot_len);
150
151 return 0;
152}
153EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
154
155/* insert an SRH within an IPv6 packet, just after the IPv6 header */
156int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
157{
158 struct ipv6hdr *hdr, *oldhdr;
159 struct ipv6_sr_hdr *isrh;
160 int hdrlen, err;
161
162 hdrlen = (osrh->hdrlen + 1) << 3;
163
164 err = skb_cow_head(skb, hdrlen + skb->mac_len);
165 if (unlikely(err))
166 return err;
167
168 oldhdr = ipv6_hdr(skb);
169
170 skb_pull(skb, sizeof(struct ipv6hdr));
171 skb_postpull_rcsum(skb, skb_network_header(skb),
172 sizeof(struct ipv6hdr));
173
174 skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
175 skb_reset_network_header(skb);
176 skb_mac_header_rebuild(skb);
177
178 hdr = ipv6_hdr(skb);
179
180 memmove(hdr, oldhdr, sizeof(*hdr));
181
182 isrh = (void *)hdr + sizeof(*hdr);
183 memcpy(isrh, osrh, hdrlen);
184
185 isrh->nexthdr = hdr->nexthdr;
186 hdr->nexthdr = NEXTHDR_ROUTING;
187
188 isrh->segments[0] = hdr->daddr;
189 hdr->daddr = isrh->segments[isrh->first_segment];
190
191#ifdef CONFIG_IPV6_SEG6_HMAC
192 if (sr_has_hmac(isrh)) {
193 struct net *net = dev_net(skb_dst(skb)->dev);
194
195 err = seg6_push_hmac(net, &hdr->saddr, isrh);
196 if (unlikely(err))
197 return err;
198 }
199#endif
200
201 skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
202
203 return 0;
204}
205EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
206
207static int seg6_do_srh(struct sk_buff *skb)
208{
209 struct dst_entry *dst = skb_dst(skb);
210 struct seg6_iptunnel_encap *tinfo;
211 int proto, err = 0;
212
213 tinfo = seg6_encap_lwtunnel(dst->lwtstate);
214
215 switch (tinfo->mode) {
216 case SEG6_IPTUN_MODE_INLINE:
217 if (skb->protocol != htons(ETH_P_IPV6))
218 return -EINVAL;
219
220 err = seg6_do_srh_inline(skb, tinfo->srh);
221 if (err)
222 return err;
223 break;
224 case SEG6_IPTUN_MODE_ENCAP:
225 err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
226 if (err)
227 return err;
228
229 if (skb->protocol == htons(ETH_P_IPV6))
230 proto = IPPROTO_IPV6;
231 else if (skb->protocol == htons(ETH_P_IP))
232 proto = IPPROTO_IPIP;
233 else
234 return -EINVAL;
235
236 err = seg6_do_srh_encap(skb, tinfo->srh, proto);
237 if (err)
238 return err;
239
240 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
241 skb_set_inner_protocol(skb, skb->protocol);
242 skb->protocol = htons(ETH_P_IPV6);
243 break;
244 case SEG6_IPTUN_MODE_L2ENCAP:
245 if (!skb_mac_header_was_set(skb))
246 return -EINVAL;
247
248 if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
249 return -ENOMEM;
250
251 skb_mac_header_rebuild(skb);
252 skb_push(skb, skb->mac_len);
253
254 err = seg6_do_srh_encap(skb, tinfo->srh, NEXTHDR_NONE);
255 if (err)
256 return err;
257
258 skb->protocol = htons(ETH_P_IPV6);
259 break;
260 }
261
262 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
263 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
264
265 return 0;
266}
267
268static int seg6_input(struct sk_buff *skb)
269{
270 struct dst_entry *orig_dst = skb_dst(skb);
271 struct dst_entry *dst = NULL;
272 struct seg6_lwt *slwt;
273 int err;
274
275 err = seg6_do_srh(skb);
276 if (unlikely(err)) {
277 kfree_skb(skb);
278 return err;
279 }
280
281 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
282
283 preempt_disable();
284 dst = dst_cache_get(&slwt->cache);
285 preempt_enable();
286
287 skb_dst_drop(skb);
288
289 if (!dst) {
290 ip6_route_input(skb);
291 dst = skb_dst(skb);
292 if (!dst->error) {
293 preempt_disable();
294 dst_cache_set_ip6(&slwt->cache, dst,
295 &ipv6_hdr(skb)->saddr);
296 preempt_enable();
297 }
298 } else {
299 skb_dst_set(skb, dst);
300 }
301
302 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
303 if (unlikely(err))
304 return err;
305
306 return dst_input(skb);
307}
308
309static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
310{
311 struct dst_entry *orig_dst = skb_dst(skb);
312 struct dst_entry *dst = NULL;
313 struct seg6_lwt *slwt;
314 int err = -EINVAL;
315
316 err = seg6_do_srh(skb);
317 if (unlikely(err))
318 goto drop;
319
320 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
321
322 preempt_disable();
323 dst = dst_cache_get(&slwt->cache);
324 preempt_enable();
325
326 if (unlikely(!dst)) {
327 struct ipv6hdr *hdr = ipv6_hdr(skb);
328 struct flowi6 fl6;
329
330 fl6.daddr = hdr->daddr;
331 fl6.saddr = hdr->saddr;
332 fl6.flowlabel = ip6_flowinfo(hdr);
333 fl6.flowi6_mark = skb->mark;
334 fl6.flowi6_proto = hdr->nexthdr;
335
336 dst = ip6_route_output(net, NULL, &fl6);
337 if (dst->error) {
338 err = dst->error;
339 dst_release(dst);
340 goto drop;
341 }
342
343 preempt_disable();
344 dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
345 preempt_enable();
346 }
347
348 skb_dst_drop(skb);
349 skb_dst_set(skb, dst);
350
351 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
352 if (unlikely(err))
353 goto drop;
354
355 return dst_output(net, sk, skb);
356drop:
357 kfree_skb(skb);
358 return err;
359}
360
361static int seg6_build_state(struct nlattr *nla,
362 unsigned int family, const void *cfg,
363 struct lwtunnel_state **ts,
364 struct netlink_ext_ack *extack)
365{
366 struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
367 struct seg6_iptunnel_encap *tuninfo;
368 struct lwtunnel_state *newts;
369 int tuninfo_len, min_size;
370 struct seg6_lwt *slwt;
371 int err;
372
373 if (family != AF_INET && family != AF_INET6)
374 return -EINVAL;
375
376 err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla,
377 seg6_iptunnel_policy, extack);
378
379 if (err < 0)
380 return err;
381
382 if (!tb[SEG6_IPTUNNEL_SRH])
383 return -EINVAL;
384
385 tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
386 tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
387
388 /* tuninfo must contain at least the iptunnel encap structure,
389 * the SRH and one segment
390 */
391 min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
392 sizeof(struct in6_addr);
393 if (tuninfo_len < min_size)
394 return -EINVAL;
395
396 switch (tuninfo->mode) {
397 case SEG6_IPTUN_MODE_INLINE:
398 if (family != AF_INET6)
399 return -EINVAL;
400
401 break;
402 case SEG6_IPTUN_MODE_ENCAP:
403 break;
404 case SEG6_IPTUN_MODE_L2ENCAP:
405 break;
406 default:
407 return -EINVAL;
408 }
409
410 /* verify that SRH is consistent */
411 if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo)))
412 return -EINVAL;
413
414 newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
415 if (!newts)
416 return -ENOMEM;
417
418 slwt = seg6_lwt_lwtunnel(newts);
419
420 err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
421 if (err) {
422 kfree(newts);
423 return err;
424 }
425
426 memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
427
428 newts->type = LWTUNNEL_ENCAP_SEG6;
429 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
430
431 if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
432 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
433
434 newts->headroom = seg6_lwt_headroom(tuninfo);
435
436 *ts = newts;
437
438 return 0;
439}
440
441static void seg6_destroy_state(struct lwtunnel_state *lwt)
442{
443 dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
444}
445
446static int seg6_fill_encap_info(struct sk_buff *skb,
447 struct lwtunnel_state *lwtstate)
448{
449 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
450
451 if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
452 return -EMSGSIZE;
453
454 return 0;
455}
456
457static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
458{
459 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
460
461 return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
462}
463
464static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
465{
466 struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
467 struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
468 int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
469
470 if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
471 return 1;
472
473 return memcmp(a_hdr, b_hdr, len);
474}
475
476static const struct lwtunnel_encap_ops seg6_iptun_ops = {
477 .build_state = seg6_build_state,
478 .destroy_state = seg6_destroy_state,
479 .output = seg6_output,
480 .input = seg6_input,
481 .fill_encap = seg6_fill_encap_info,
482 .get_encap_size = seg6_encap_nlsize,
483 .cmp_encap = seg6_encap_cmp,
484 .owner = THIS_MODULE,
485};
486
487int __init seg6_iptunnel_init(void)
488{
489 return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
490}
491
492void seg6_iptunnel_exit(void)
493{
494 lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
495}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * SR-IPv6 implementation
4 *
5 * Author:
6 * David Lebrun <david.lebrun@uclouvain.be>
7 */
8
9#include <linux/types.h>
10#include <linux/skbuff.h>
11#include <linux/net.h>
12#include <linux/module.h>
13#include <net/ip.h>
14#include <net/ip_tunnels.h>
15#include <net/lwtunnel.h>
16#include <net/netevent.h>
17#include <net/netns/generic.h>
18#include <net/ip6_fib.h>
19#include <net/route.h>
20#include <net/seg6.h>
21#include <linux/seg6.h>
22#include <linux/seg6_iptunnel.h>
23#include <net/addrconf.h>
24#include <net/ip6_route.h>
25#include <net/dst_cache.h>
26#ifdef CONFIG_IPV6_SEG6_HMAC
27#include <net/seg6_hmac.h>
28#endif
29
30static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)
31{
32 int head = 0;
33
34 switch (tuninfo->mode) {
35 case SEG6_IPTUN_MODE_INLINE:
36 break;
37 case SEG6_IPTUN_MODE_ENCAP:
38 head = sizeof(struct ipv6hdr);
39 break;
40 case SEG6_IPTUN_MODE_L2ENCAP:
41 return 0;
42 }
43
44 return ((tuninfo->srh->hdrlen + 1) << 3) + head;
45}
46
47struct seg6_lwt {
48 struct dst_cache cache;
49 struct seg6_iptunnel_encap tuninfo[];
50};
51
52static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt)
53{
54 return (struct seg6_lwt *)lwt->data;
55}
56
57static inline struct seg6_iptunnel_encap *
58seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
59{
60 return seg6_lwt_lwtunnel(lwt)->tuninfo;
61}
62
63static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
64 [SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
65};
66
67static int nla_put_srh(struct sk_buff *skb, int attrtype,
68 struct seg6_iptunnel_encap *tuninfo)
69{
70 struct seg6_iptunnel_encap *data;
71 struct nlattr *nla;
72 int len;
73
74 len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
75
76 nla = nla_reserve(skb, attrtype, len);
77 if (!nla)
78 return -EMSGSIZE;
79
80 data = nla_data(nla);
81 memcpy(data, tuninfo, len);
82
83 return 0;
84}
85
86static void set_tun_src(struct net *net, struct net_device *dev,
87 struct in6_addr *daddr, struct in6_addr *saddr)
88{
89 struct seg6_pernet_data *sdata = seg6_pernet(net);
90 struct in6_addr *tun_src;
91
92 rcu_read_lock();
93
94 tun_src = rcu_dereference(sdata->tun_src);
95
96 if (!ipv6_addr_any(tun_src)) {
97 memcpy(saddr, tun_src, sizeof(struct in6_addr));
98 } else {
99 ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
100 saddr);
101 }
102
103 rcu_read_unlock();
104}
105
106/* Compute flowlabel for outer IPv6 header */
107static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb,
108 struct ipv6hdr *inner_hdr)
109{
110 int do_flowlabel = net->ipv6.sysctl.seg6_flowlabel;
111 __be32 flowlabel = 0;
112 u32 hash;
113
114 if (do_flowlabel > 0) {
115 hash = skb_get_hash(skb);
116 hash = rol32(hash, 16);
117 flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
118 } else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
119 flowlabel = ip6_flowlabel(inner_hdr);
120 }
121 return flowlabel;
122}
123
124/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
125int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
126{
127 struct dst_entry *dst = skb_dst(skb);
128 struct net *net = dev_net(dst->dev);
129 struct ipv6hdr *hdr, *inner_hdr;
130 struct ipv6_sr_hdr *isrh;
131 int hdrlen, tot_len, err;
132 __be32 flowlabel;
133
134 hdrlen = (osrh->hdrlen + 1) << 3;
135 tot_len = hdrlen + sizeof(*hdr);
136
137 err = skb_cow_head(skb, tot_len + skb->mac_len);
138 if (unlikely(err))
139 return err;
140
141 inner_hdr = ipv6_hdr(skb);
142 flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
143
144 skb_push(skb, tot_len);
145 skb_reset_network_header(skb);
146 skb_mac_header_rebuild(skb);
147 hdr = ipv6_hdr(skb);
148
149 /* inherit tc, flowlabel and hlim
150 * hlim will be decremented in ip6_forward() afterwards and
151 * decapsulation will overwrite inner hlim with outer hlim
152 */
153
154 if (skb->protocol == htons(ETH_P_IPV6)) {
155 ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
156 flowlabel);
157 hdr->hop_limit = inner_hdr->hop_limit;
158 } else {
159 ip6_flow_hdr(hdr, 0, flowlabel);
160 hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
161
162 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
163 }
164
165 hdr->nexthdr = NEXTHDR_ROUTING;
166
167 isrh = (void *)hdr + sizeof(*hdr);
168 memcpy(isrh, osrh, hdrlen);
169
170 isrh->nexthdr = proto;
171
172 hdr->daddr = isrh->segments[isrh->first_segment];
173 set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
174
175#ifdef CONFIG_IPV6_SEG6_HMAC
176 if (sr_has_hmac(isrh)) {
177 err = seg6_push_hmac(net, &hdr->saddr, isrh);
178 if (unlikely(err))
179 return err;
180 }
181#endif
182
183 skb_postpush_rcsum(skb, hdr, tot_len);
184
185 return 0;
186}
187EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
188
189/* insert an SRH within an IPv6 packet, just after the IPv6 header */
190int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
191{
192 struct ipv6hdr *hdr, *oldhdr;
193 struct ipv6_sr_hdr *isrh;
194 int hdrlen, err;
195
196 hdrlen = (osrh->hdrlen + 1) << 3;
197
198 err = skb_cow_head(skb, hdrlen + skb->mac_len);
199 if (unlikely(err))
200 return err;
201
202 oldhdr = ipv6_hdr(skb);
203
204 skb_pull(skb, sizeof(struct ipv6hdr));
205 skb_postpull_rcsum(skb, skb_network_header(skb),
206 sizeof(struct ipv6hdr));
207
208 skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
209 skb_reset_network_header(skb);
210 skb_mac_header_rebuild(skb);
211
212 hdr = ipv6_hdr(skb);
213
214 memmove(hdr, oldhdr, sizeof(*hdr));
215
216 isrh = (void *)hdr + sizeof(*hdr);
217 memcpy(isrh, osrh, hdrlen);
218
219 isrh->nexthdr = hdr->nexthdr;
220 hdr->nexthdr = NEXTHDR_ROUTING;
221
222 isrh->segments[0] = hdr->daddr;
223 hdr->daddr = isrh->segments[isrh->first_segment];
224
225#ifdef CONFIG_IPV6_SEG6_HMAC
226 if (sr_has_hmac(isrh)) {
227 struct net *net = dev_net(skb_dst(skb)->dev);
228
229 err = seg6_push_hmac(net, &hdr->saddr, isrh);
230 if (unlikely(err))
231 return err;
232 }
233#endif
234
235 skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
236
237 return 0;
238}
239EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
240
241static int seg6_do_srh(struct sk_buff *skb)
242{
243 struct dst_entry *dst = skb_dst(skb);
244 struct seg6_iptunnel_encap *tinfo;
245 int proto, err = 0;
246
247 tinfo = seg6_encap_lwtunnel(dst->lwtstate);
248
249 switch (tinfo->mode) {
250 case SEG6_IPTUN_MODE_INLINE:
251 if (skb->protocol != htons(ETH_P_IPV6))
252 return -EINVAL;
253
254 err = seg6_do_srh_inline(skb, tinfo->srh);
255 if (err)
256 return err;
257 break;
258 case SEG6_IPTUN_MODE_ENCAP:
259 err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
260 if (err)
261 return err;
262
263 if (skb->protocol == htons(ETH_P_IPV6))
264 proto = IPPROTO_IPV6;
265 else if (skb->protocol == htons(ETH_P_IP))
266 proto = IPPROTO_IPIP;
267 else
268 return -EINVAL;
269
270 err = seg6_do_srh_encap(skb, tinfo->srh, proto);
271 if (err)
272 return err;
273
274 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
275 skb_set_inner_protocol(skb, skb->protocol);
276 skb->protocol = htons(ETH_P_IPV6);
277 break;
278 case SEG6_IPTUN_MODE_L2ENCAP:
279 if (!skb_mac_header_was_set(skb))
280 return -EINVAL;
281
282 if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
283 return -ENOMEM;
284
285 skb_mac_header_rebuild(skb);
286 skb_push(skb, skb->mac_len);
287
288 err = seg6_do_srh_encap(skb, tinfo->srh, IPPROTO_ETHERNET);
289 if (err)
290 return err;
291
292 skb->protocol = htons(ETH_P_IPV6);
293 break;
294 }
295
296 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
297 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
298
299 return 0;
300}
301
302static int seg6_input(struct sk_buff *skb)
303{
304 struct dst_entry *orig_dst = skb_dst(skb);
305 struct dst_entry *dst = NULL;
306 struct seg6_lwt *slwt;
307 int err;
308
309 err = seg6_do_srh(skb);
310 if (unlikely(err)) {
311 kfree_skb(skb);
312 return err;
313 }
314
315 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
316
317 preempt_disable();
318 dst = dst_cache_get(&slwt->cache);
319 preempt_enable();
320
321 skb_dst_drop(skb);
322
323 if (!dst) {
324 ip6_route_input(skb);
325 dst = skb_dst(skb);
326 if (!dst->error) {
327 preempt_disable();
328 dst_cache_set_ip6(&slwt->cache, dst,
329 &ipv6_hdr(skb)->saddr);
330 preempt_enable();
331 }
332 } else {
333 skb_dst_set(skb, dst);
334 }
335
336 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
337 if (unlikely(err))
338 return err;
339
340 return dst_input(skb);
341}
342
343static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
344{
345 struct dst_entry *orig_dst = skb_dst(skb);
346 struct dst_entry *dst = NULL;
347 struct seg6_lwt *slwt;
348 int err = -EINVAL;
349
350 err = seg6_do_srh(skb);
351 if (unlikely(err))
352 goto drop;
353
354 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
355
356 preempt_disable();
357 dst = dst_cache_get(&slwt->cache);
358 preempt_enable();
359
360 if (unlikely(!dst)) {
361 struct ipv6hdr *hdr = ipv6_hdr(skb);
362 struct flowi6 fl6;
363
364 memset(&fl6, 0, sizeof(fl6));
365 fl6.daddr = hdr->daddr;
366 fl6.saddr = hdr->saddr;
367 fl6.flowlabel = ip6_flowinfo(hdr);
368 fl6.flowi6_mark = skb->mark;
369 fl6.flowi6_proto = hdr->nexthdr;
370
371 dst = ip6_route_output(net, NULL, &fl6);
372 if (dst->error) {
373 err = dst->error;
374 dst_release(dst);
375 goto drop;
376 }
377
378 preempt_disable();
379 dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
380 preempt_enable();
381 }
382
383 skb_dst_drop(skb);
384 skb_dst_set(skb, dst);
385
386 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
387 if (unlikely(err))
388 goto drop;
389
390 return dst_output(net, sk, skb);
391drop:
392 kfree_skb(skb);
393 return err;
394}
395
396static int seg6_build_state(struct net *net, struct nlattr *nla,
397 unsigned int family, const void *cfg,
398 struct lwtunnel_state **ts,
399 struct netlink_ext_ack *extack)
400{
401 struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
402 struct seg6_iptunnel_encap *tuninfo;
403 struct lwtunnel_state *newts;
404 int tuninfo_len, min_size;
405 struct seg6_lwt *slwt;
406 int err;
407
408 if (family != AF_INET && family != AF_INET6)
409 return -EINVAL;
410
411 err = nla_parse_nested_deprecated(tb, SEG6_IPTUNNEL_MAX, nla,
412 seg6_iptunnel_policy, extack);
413
414 if (err < 0)
415 return err;
416
417 if (!tb[SEG6_IPTUNNEL_SRH])
418 return -EINVAL;
419
420 tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
421 tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
422
423 /* tuninfo must contain at least the iptunnel encap structure,
424 * the SRH and one segment
425 */
426 min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
427 sizeof(struct in6_addr);
428 if (tuninfo_len < min_size)
429 return -EINVAL;
430
431 switch (tuninfo->mode) {
432 case SEG6_IPTUN_MODE_INLINE:
433 if (family != AF_INET6)
434 return -EINVAL;
435
436 break;
437 case SEG6_IPTUN_MODE_ENCAP:
438 break;
439 case SEG6_IPTUN_MODE_L2ENCAP:
440 break;
441 default:
442 return -EINVAL;
443 }
444
445 /* verify that SRH is consistent */
446 if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo), false))
447 return -EINVAL;
448
449 newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
450 if (!newts)
451 return -ENOMEM;
452
453 slwt = seg6_lwt_lwtunnel(newts);
454
455 err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
456 if (err) {
457 kfree(newts);
458 return err;
459 }
460
461 memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
462
463 newts->type = LWTUNNEL_ENCAP_SEG6;
464 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
465
466 if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
467 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
468
469 newts->headroom = seg6_lwt_headroom(tuninfo);
470
471 *ts = newts;
472
473 return 0;
474}
475
476static void seg6_destroy_state(struct lwtunnel_state *lwt)
477{
478 dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
479}
480
481static int seg6_fill_encap_info(struct sk_buff *skb,
482 struct lwtunnel_state *lwtstate)
483{
484 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
485
486 if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
487 return -EMSGSIZE;
488
489 return 0;
490}
491
492static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
493{
494 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
495
496 return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
497}
498
499static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
500{
501 struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
502 struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
503 int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
504
505 if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
506 return 1;
507
508 return memcmp(a_hdr, b_hdr, len);
509}
510
511static const struct lwtunnel_encap_ops seg6_iptun_ops = {
512 .build_state = seg6_build_state,
513 .destroy_state = seg6_destroy_state,
514 .output = seg6_output,
515 .input = seg6_input,
516 .fill_encap = seg6_fill_encap_info,
517 .get_encap_size = seg6_encap_nlsize,
518 .cmp_encap = seg6_encap_cmp,
519 .owner = THIS_MODULE,
520};
521
522int __init seg6_iptunnel_init(void)
523{
524 return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
525}
526
527void seg6_iptunnel_exit(void)
528{
529 lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
530}