1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * SR-IPv6 implementation
4 *
5 * Authors:
6 * David Lebrun <david.lebrun@uclouvain.be>
7 * eBPF support: Mathieu Xhonneux <m.xhonneux@gmail.com>
8 */
9
10 #include <linux/types.h>
11 #include <linux/skbuff.h>
12 #include <linux/net.h>
13 #include <linux/module.h>
14 #include <net/ip.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_local.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 #include <net/seg6_local.h>
30 #include <linux/etherdevice.h>
31 #include <linux/bpf.h>
32
33 struct seg6_local_lwt;
34
35 struct seg6_action_desc {
36 int action;
37 unsigned long attrs;
38 int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
39 int static_headroom;
40 };
41
42 struct bpf_lwt_prog {
43 struct bpf_prog *prog;
44 char *name;
45 };
46
47 struct seg6_local_lwt {
48 int action;
49 struct ipv6_sr_hdr *srh;
50 int table;
51 struct in_addr nh4;
52 struct in6_addr nh6;
53 int iif;
54 int oif;
55 struct bpf_lwt_prog bpf;
56
57 int headroom;
58 struct seg6_action_desc *desc;
59 };
60
seg6_local_lwtunnel(struct lwtunnel_state * lwt)61 static struct seg6_local_lwt *seg6_local_lwtunnel(struct lwtunnel_state *lwt)
62 {
63 return (struct seg6_local_lwt *)lwt->data;
64 }
65
get_srh(struct sk_buff * skb)66 static struct ipv6_sr_hdr *get_srh(struct sk_buff *skb)
67 {
68 struct ipv6_sr_hdr *srh;
69 int len, srhoff = 0;
70
71 if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, NULL) < 0)
72 return NULL;
73
74 if (!pskb_may_pull(skb, srhoff + sizeof(*srh)))
75 return NULL;
76
77 srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
78
79 len = (srh->hdrlen + 1) << 3;
80
81 if (!pskb_may_pull(skb, srhoff + len))
82 return NULL;
83
84 /* note that pskb_may_pull may change pointers in header;
85 * for this reason it is necessary to reload them when needed.
86 */
87 srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
88
89 if (!seg6_validate_srh(srh, len))
90 return NULL;
91
92 return srh;
93 }
94
get_and_validate_srh(struct sk_buff * skb)95 static struct ipv6_sr_hdr *get_and_validate_srh(struct sk_buff *skb)
96 {
97 struct ipv6_sr_hdr *srh;
98
99 srh = get_srh(skb);
100 if (!srh)
101 return NULL;
102
103 if (srh->segments_left == 0)
104 return NULL;
105
106 #ifdef CONFIG_IPV6_SEG6_HMAC
107 if (!seg6_hmac_validate_skb(skb))
108 return NULL;
109 #endif
110
111 return srh;
112 }
113
decap_and_validate(struct sk_buff * skb,int proto)114 static bool decap_and_validate(struct sk_buff *skb, int proto)
115 {
116 struct ipv6_sr_hdr *srh;
117 unsigned int off = 0;
118
119 srh = get_srh(skb);
120 if (srh && srh->segments_left > 0)
121 return false;
122
123 #ifdef CONFIG_IPV6_SEG6_HMAC
124 if (srh && !seg6_hmac_validate_skb(skb))
125 return false;
126 #endif
127
128 if (ipv6_find_hdr(skb, &off, proto, NULL, NULL) < 0)
129 return false;
130
131 if (!pskb_pull(skb, off))
132 return false;
133
134 skb_postpull_rcsum(skb, skb_network_header(skb), off);
135
136 skb_reset_network_header(skb);
137 skb_reset_transport_header(skb);
138 skb->encapsulation = 0;
139
140 return true;
141 }
142
advance_nextseg(struct ipv6_sr_hdr * srh,struct in6_addr * daddr)143 static void advance_nextseg(struct ipv6_sr_hdr *srh, struct in6_addr *daddr)
144 {
145 struct in6_addr *addr;
146
147 srh->segments_left--;
148 addr = srh->segments + srh->segments_left;
149 *daddr = *addr;
150 }
151
seg6_lookup_nexthop(struct sk_buff * skb,struct in6_addr * nhaddr,u32 tbl_id)152 int seg6_lookup_nexthop(struct sk_buff *skb, struct in6_addr *nhaddr,
153 u32 tbl_id)
154 {
155 struct net *net = dev_net(skb->dev);
156 struct ipv6hdr *hdr = ipv6_hdr(skb);
157 int flags = RT6_LOOKUP_F_HAS_SADDR;
158 struct dst_entry *dst = NULL;
159 struct rt6_info *rt;
160 struct flowi6 fl6;
161
162 fl6.flowi6_iif = skb->dev->ifindex;
163 fl6.daddr = nhaddr ? *nhaddr : hdr->daddr;
164 fl6.saddr = hdr->saddr;
165 fl6.flowlabel = ip6_flowinfo(hdr);
166 fl6.flowi6_mark = skb->mark;
167 fl6.flowi6_proto = hdr->nexthdr;
168
169 if (nhaddr)
170 fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
171
172 if (!tbl_id) {
173 dst = ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags);
174 } else {
175 struct fib6_table *table;
176
177 table = fib6_get_table(net, tbl_id);
178 if (!table)
179 goto out;
180
181 rt = ip6_pol_route(net, table, 0, &fl6, skb, flags);
182 dst = &rt->dst;
183 }
184
185 if (dst && dst->dev->flags & IFF_LOOPBACK && !dst->error) {
186 dst_release(dst);
187 dst = NULL;
188 }
189
190 out:
191 if (!dst) {
192 rt = net->ipv6.ip6_blk_hole_entry;
193 dst = &rt->dst;
194 dst_hold(dst);
195 }
196
197 skb_dst_drop(skb);
198 skb_dst_set(skb, dst);
199 return dst->error;
200 }
201
202 /* regular endpoint function */
input_action_end(struct sk_buff * skb,struct seg6_local_lwt * slwt)203 static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)
204 {
205 struct ipv6_sr_hdr *srh;
206
207 srh = get_and_validate_srh(skb);
208 if (!srh)
209 goto drop;
210
211 advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
212
213 seg6_lookup_nexthop(skb, NULL, 0);
214
215 return dst_input(skb);
216
217 drop:
218 kfree_skb(skb);
219 return -EINVAL;
220 }
221
222 /* regular endpoint, and forward to specified nexthop */
input_action_end_x(struct sk_buff * skb,struct seg6_local_lwt * slwt)223 static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt)
224 {
225 struct ipv6_sr_hdr *srh;
226
227 srh = get_and_validate_srh(skb);
228 if (!srh)
229 goto drop;
230
231 advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
232
233 seg6_lookup_nexthop(skb, &slwt->nh6, 0);
234
235 return dst_input(skb);
236
237 drop:
238 kfree_skb(skb);
239 return -EINVAL;
240 }
241
input_action_end_t(struct sk_buff * skb,struct seg6_local_lwt * slwt)242 static int input_action_end_t(struct sk_buff *skb, struct seg6_local_lwt *slwt)
243 {
244 struct ipv6_sr_hdr *srh;
245
246 srh = get_and_validate_srh(skb);
247 if (!srh)
248 goto drop;
249
250 advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
251
252 seg6_lookup_nexthop(skb, NULL, slwt->table);
253
254 return dst_input(skb);
255
256 drop:
257 kfree_skb(skb);
258 return -EINVAL;
259 }
260
261 /* decapsulate and forward inner L2 frame on specified interface */
input_action_end_dx2(struct sk_buff * skb,struct seg6_local_lwt * slwt)262 static int input_action_end_dx2(struct sk_buff *skb,
263 struct seg6_local_lwt *slwt)
264 {
265 struct net *net = dev_net(skb->dev);
266 struct net_device *odev;
267 struct ethhdr *eth;
268
269 if (!decap_and_validate(skb, NEXTHDR_NONE))
270 goto drop;
271
272 if (!pskb_may_pull(skb, ETH_HLEN))
273 goto drop;
274
275 skb_reset_mac_header(skb);
276 eth = (struct ethhdr *)skb->data;
277
278 /* To determine the frame's protocol, we assume it is 802.3. This avoids
279 * a call to eth_type_trans(), which is not really relevant for our
280 * use case.
281 */
282 if (!eth_proto_is_802_3(eth->h_proto))
283 goto drop;
284
285 odev = dev_get_by_index_rcu(net, slwt->oif);
286 if (!odev)
287 goto drop;
288
289 /* As we accept Ethernet frames, make sure the egress device is of
290 * the correct type.
291 */
292 if (odev->type != ARPHRD_ETHER)
293 goto drop;
294
295 if (!(odev->flags & IFF_UP) || !netif_carrier_ok(odev))
296 goto drop;
297
298 skb_orphan(skb);
299
300 if (skb_warn_if_lro(skb))
301 goto drop;
302
303 skb_forward_csum(skb);
304
305 if (skb->len - ETH_HLEN > odev->mtu)
306 goto drop;
307
308 skb->dev = odev;
309 skb->protocol = eth->h_proto;
310
311 return dev_queue_xmit(skb);
312
313 drop:
314 kfree_skb(skb);
315 return -EINVAL;
316 }
317
318 /* decapsulate and forward to specified nexthop */
input_action_end_dx6(struct sk_buff * skb,struct seg6_local_lwt * slwt)319 static int input_action_end_dx6(struct sk_buff *skb,
320 struct seg6_local_lwt *slwt)
321 {
322 struct in6_addr *nhaddr = NULL;
323
324 /* this function accepts IPv6 encapsulated packets, with either
325 * an SRH with SL=0, or no SRH.
326 */
327
328 if (!decap_and_validate(skb, IPPROTO_IPV6))
329 goto drop;
330
331 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
332 goto drop;
333
334 /* The inner packet is not associated to any local interface,
335 * so we do not call netif_rx().
336 *
337 * If slwt->nh6 is set to ::, then lookup the nexthop for the
338 * inner packet's DA. Otherwise, use the specified nexthop.
339 */
340
341 if (!ipv6_addr_any(&slwt->nh6))
342 nhaddr = &slwt->nh6;
343
344 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
345
346 seg6_lookup_nexthop(skb, nhaddr, 0);
347
348 return dst_input(skb);
349 drop:
350 kfree_skb(skb);
351 return -EINVAL;
352 }
353
input_action_end_dx4(struct sk_buff * skb,struct seg6_local_lwt * slwt)354 static int input_action_end_dx4(struct sk_buff *skb,
355 struct seg6_local_lwt *slwt)
356 {
357 struct iphdr *iph;
358 __be32 nhaddr;
359 int err;
360
361 if (!decap_and_validate(skb, IPPROTO_IPIP))
362 goto drop;
363
364 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
365 goto drop;
366
367 skb->protocol = htons(ETH_P_IP);
368
369 iph = ip_hdr(skb);
370
371 nhaddr = slwt->nh4.s_addr ?: iph->daddr;
372
373 skb_dst_drop(skb);
374
375 skb_set_transport_header(skb, sizeof(struct iphdr));
376
377 err = ip_route_input(skb, nhaddr, iph->saddr, 0, skb->dev);
378 if (err)
379 goto drop;
380
381 return dst_input(skb);
382
383 drop:
384 kfree_skb(skb);
385 return -EINVAL;
386 }
387
input_action_end_dt6(struct sk_buff * skb,struct seg6_local_lwt * slwt)388 static int input_action_end_dt6(struct sk_buff *skb,
389 struct seg6_local_lwt *slwt)
390 {
391 if (!decap_and_validate(skb, IPPROTO_IPV6))
392 goto drop;
393
394 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
395 goto drop;
396
397 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
398
399 seg6_lookup_nexthop(skb, NULL, slwt->table);
400
401 return dst_input(skb);
402
403 drop:
404 kfree_skb(skb);
405 return -EINVAL;
406 }
407
408 /* push an SRH on top of the current one */
input_action_end_b6(struct sk_buff * skb,struct seg6_local_lwt * slwt)409 static int input_action_end_b6(struct sk_buff *skb, struct seg6_local_lwt *slwt)
410 {
411 struct ipv6_sr_hdr *srh;
412 int err = -EINVAL;
413
414 srh = get_and_validate_srh(skb);
415 if (!srh)
416 goto drop;
417
418 err = seg6_do_srh_inline(skb, slwt->srh);
419 if (err)
420 goto drop;
421
422 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
423 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
424
425 seg6_lookup_nexthop(skb, NULL, 0);
426
427 return dst_input(skb);
428
429 drop:
430 kfree_skb(skb);
431 return err;
432 }
433
434 /* encapsulate within an outer IPv6 header and a specified SRH */
input_action_end_b6_encap(struct sk_buff * skb,struct seg6_local_lwt * slwt)435 static int input_action_end_b6_encap(struct sk_buff *skb,
436 struct seg6_local_lwt *slwt)
437 {
438 struct ipv6_sr_hdr *srh;
439 int err = -EINVAL;
440
441 srh = get_and_validate_srh(skb);
442 if (!srh)
443 goto drop;
444
445 advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
446
447 skb_reset_inner_headers(skb);
448 skb->encapsulation = 1;
449
450 err = seg6_do_srh_encap(skb, slwt->srh, IPPROTO_IPV6);
451 if (err)
452 goto drop;
453
454 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
455 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
456
457 seg6_lookup_nexthop(skb, NULL, 0);
458
459 return dst_input(skb);
460
461 drop:
462 kfree_skb(skb);
463 return err;
464 }
465
466 DEFINE_PER_CPU(struct seg6_bpf_srh_state, seg6_bpf_srh_states);
467
seg6_bpf_has_valid_srh(struct sk_buff * skb)468 bool seg6_bpf_has_valid_srh(struct sk_buff *skb)
469 {
470 struct seg6_bpf_srh_state *srh_state =
471 this_cpu_ptr(&seg6_bpf_srh_states);
472 struct ipv6_sr_hdr *srh = srh_state->srh;
473
474 if (unlikely(srh == NULL))
475 return false;
476
477 if (unlikely(!srh_state->valid)) {
478 if ((srh_state->hdrlen & 7) != 0)
479 return false;
480
481 srh->hdrlen = (u8)(srh_state->hdrlen >> 3);
482 if (!seg6_validate_srh(srh, (srh->hdrlen + 1) << 3))
483 return false;
484
485 srh_state->valid = true;
486 }
487
488 return true;
489 }
490
input_action_end_bpf(struct sk_buff * skb,struct seg6_local_lwt * slwt)491 static int input_action_end_bpf(struct sk_buff *skb,
492 struct seg6_local_lwt *slwt)
493 {
494 struct seg6_bpf_srh_state *srh_state =
495 this_cpu_ptr(&seg6_bpf_srh_states);
496 struct ipv6_sr_hdr *srh;
497 int ret;
498
499 srh = get_and_validate_srh(skb);
500 if (!srh) {
501 kfree_skb(skb);
502 return -EINVAL;
503 }
504 advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
505
506 /* preempt_disable is needed to protect the per-CPU buffer srh_state,
507 * which is also accessed by the bpf_lwt_seg6_* helpers
508 */
509 preempt_disable();
510 srh_state->srh = srh;
511 srh_state->hdrlen = srh->hdrlen << 3;
512 srh_state->valid = true;
513
514 rcu_read_lock();
515 bpf_compute_data_pointers(skb);
516 ret = bpf_prog_run_save_cb(slwt->bpf.prog, skb);
517 rcu_read_unlock();
518
519 switch (ret) {
520 case BPF_OK:
521 case BPF_REDIRECT:
522 break;
523 case BPF_DROP:
524 goto drop;
525 default:
526 pr_warn_once("bpf-seg6local: Illegal return value %u\n", ret);
527 goto drop;
528 }
529
530 if (srh_state->srh && !seg6_bpf_has_valid_srh(skb))
531 goto drop;
532
533 preempt_enable();
534 if (ret != BPF_REDIRECT)
535 seg6_lookup_nexthop(skb, NULL, 0);
536
537 return dst_input(skb);
538
539 drop:
540 preempt_enable();
541 kfree_skb(skb);
542 return -EINVAL;
543 }
544
545 static struct seg6_action_desc seg6_action_table[] = {
546 {
547 .action = SEG6_LOCAL_ACTION_END,
548 .attrs = 0,
549 .input = input_action_end,
550 },
551 {
552 .action = SEG6_LOCAL_ACTION_END_X,
553 .attrs = (1 << SEG6_LOCAL_NH6),
554 .input = input_action_end_x,
555 },
556 {
557 .action = SEG6_LOCAL_ACTION_END_T,
558 .attrs = (1 << SEG6_LOCAL_TABLE),
559 .input = input_action_end_t,
560 },
561 {
562 .action = SEG6_LOCAL_ACTION_END_DX2,
563 .attrs = (1 << SEG6_LOCAL_OIF),
564 .input = input_action_end_dx2,
565 },
566 {
567 .action = SEG6_LOCAL_ACTION_END_DX6,
568 .attrs = (1 << SEG6_LOCAL_NH6),
569 .input = input_action_end_dx6,
570 },
571 {
572 .action = SEG6_LOCAL_ACTION_END_DX4,
573 .attrs = (1 << SEG6_LOCAL_NH4),
574 .input = input_action_end_dx4,
575 },
576 {
577 .action = SEG6_LOCAL_ACTION_END_DT6,
578 .attrs = (1 << SEG6_LOCAL_TABLE),
579 .input = input_action_end_dt6,
580 },
581 {
582 .action = SEG6_LOCAL_ACTION_END_B6,
583 .attrs = (1 << SEG6_LOCAL_SRH),
584 .input = input_action_end_b6,
585 },
586 {
587 .action = SEG6_LOCAL_ACTION_END_B6_ENCAP,
588 .attrs = (1 << SEG6_LOCAL_SRH),
589 .input = input_action_end_b6_encap,
590 .static_headroom = sizeof(struct ipv6hdr),
591 },
592 {
593 .action = SEG6_LOCAL_ACTION_END_BPF,
594 .attrs = (1 << SEG6_LOCAL_BPF),
595 .input = input_action_end_bpf,
596 },
597
598 };
599
__get_action_desc(int action)600 static struct seg6_action_desc *__get_action_desc(int action)
601 {
602 struct seg6_action_desc *desc;
603 int i, count;
604
605 count = ARRAY_SIZE(seg6_action_table);
606 for (i = 0; i < count; i++) {
607 desc = &seg6_action_table[i];
608 if (desc->action == action)
609 return desc;
610 }
611
612 return NULL;
613 }
614
seg6_local_input(struct sk_buff * skb)615 static int seg6_local_input(struct sk_buff *skb)
616 {
617 struct dst_entry *orig_dst = skb_dst(skb);
618 struct seg6_action_desc *desc;
619 struct seg6_local_lwt *slwt;
620
621 if (skb->protocol != htons(ETH_P_IPV6)) {
622 kfree_skb(skb);
623 return -EINVAL;
624 }
625
626 slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
627 desc = slwt->desc;
628
629 return desc->input(skb, slwt);
630 }
631
632 static const struct nla_policy seg6_local_policy[SEG6_LOCAL_MAX + 1] = {
633 [SEG6_LOCAL_ACTION] = { .type = NLA_U32 },
634 [SEG6_LOCAL_SRH] = { .type = NLA_BINARY },
635 [SEG6_LOCAL_TABLE] = { .type = NLA_U32 },
636 [SEG6_LOCAL_NH4] = { .type = NLA_BINARY,
637 .len = sizeof(struct in_addr) },
638 [SEG6_LOCAL_NH6] = { .type = NLA_BINARY,
639 .len = sizeof(struct in6_addr) },
640 [SEG6_LOCAL_IIF] = { .type = NLA_U32 },
641 [SEG6_LOCAL_OIF] = { .type = NLA_U32 },
642 [SEG6_LOCAL_BPF] = { .type = NLA_NESTED },
643 };
644
parse_nla_srh(struct nlattr ** attrs,struct seg6_local_lwt * slwt)645 static int parse_nla_srh(struct nlattr **attrs, struct seg6_local_lwt *slwt)
646 {
647 struct ipv6_sr_hdr *srh;
648 int len;
649
650 srh = nla_data(attrs[SEG6_LOCAL_SRH]);
651 len = nla_len(attrs[SEG6_LOCAL_SRH]);
652
653 /* SRH must contain at least one segment */
654 if (len < sizeof(*srh) + sizeof(struct in6_addr))
655 return -EINVAL;
656
657 if (!seg6_validate_srh(srh, len))
658 return -EINVAL;
659
660 slwt->srh = kmemdup(srh, len, GFP_KERNEL);
661 if (!slwt->srh)
662 return -ENOMEM;
663
664 slwt->headroom += len;
665
666 return 0;
667 }
668
put_nla_srh(struct sk_buff * skb,struct seg6_local_lwt * slwt)669 static int put_nla_srh(struct sk_buff *skb, struct seg6_local_lwt *slwt)
670 {
671 struct ipv6_sr_hdr *srh;
672 struct nlattr *nla;
673 int len;
674
675 srh = slwt->srh;
676 len = (srh->hdrlen + 1) << 3;
677
678 nla = nla_reserve(skb, SEG6_LOCAL_SRH, len);
679 if (!nla)
680 return -EMSGSIZE;
681
682 memcpy(nla_data(nla), srh, len);
683
684 return 0;
685 }
686
cmp_nla_srh(struct seg6_local_lwt * a,struct seg6_local_lwt * b)687 static int cmp_nla_srh(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
688 {
689 int len = (a->srh->hdrlen + 1) << 3;
690
691 if (len != ((b->srh->hdrlen + 1) << 3))
692 return 1;
693
694 return memcmp(a->srh, b->srh, len);
695 }
696
parse_nla_table(struct nlattr ** attrs,struct seg6_local_lwt * slwt)697 static int parse_nla_table(struct nlattr **attrs, struct seg6_local_lwt *slwt)
698 {
699 slwt->table = nla_get_u32(attrs[SEG6_LOCAL_TABLE]);
700
701 return 0;
702 }
703
put_nla_table(struct sk_buff * skb,struct seg6_local_lwt * slwt)704 static int put_nla_table(struct sk_buff *skb, struct seg6_local_lwt *slwt)
705 {
706 if (nla_put_u32(skb, SEG6_LOCAL_TABLE, slwt->table))
707 return -EMSGSIZE;
708
709 return 0;
710 }
711
cmp_nla_table(struct seg6_local_lwt * a,struct seg6_local_lwt * b)712 static int cmp_nla_table(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
713 {
714 if (a->table != b->table)
715 return 1;
716
717 return 0;
718 }
719
parse_nla_nh4(struct nlattr ** attrs,struct seg6_local_lwt * slwt)720 static int parse_nla_nh4(struct nlattr **attrs, struct seg6_local_lwt *slwt)
721 {
722 memcpy(&slwt->nh4, nla_data(attrs[SEG6_LOCAL_NH4]),
723 sizeof(struct in_addr));
724
725 return 0;
726 }
727
put_nla_nh4(struct sk_buff * skb,struct seg6_local_lwt * slwt)728 static int put_nla_nh4(struct sk_buff *skb, struct seg6_local_lwt *slwt)
729 {
730 struct nlattr *nla;
731
732 nla = nla_reserve(skb, SEG6_LOCAL_NH4, sizeof(struct in_addr));
733 if (!nla)
734 return -EMSGSIZE;
735
736 memcpy(nla_data(nla), &slwt->nh4, sizeof(struct in_addr));
737
738 return 0;
739 }
740
cmp_nla_nh4(struct seg6_local_lwt * a,struct seg6_local_lwt * b)741 static int cmp_nla_nh4(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
742 {
743 return memcmp(&a->nh4, &b->nh4, sizeof(struct in_addr));
744 }
745
parse_nla_nh6(struct nlattr ** attrs,struct seg6_local_lwt * slwt)746 static int parse_nla_nh6(struct nlattr **attrs, struct seg6_local_lwt *slwt)
747 {
748 memcpy(&slwt->nh6, nla_data(attrs[SEG6_LOCAL_NH6]),
749 sizeof(struct in6_addr));
750
751 return 0;
752 }
753
put_nla_nh6(struct sk_buff * skb,struct seg6_local_lwt * slwt)754 static int put_nla_nh6(struct sk_buff *skb, struct seg6_local_lwt *slwt)
755 {
756 struct nlattr *nla;
757
758 nla = nla_reserve(skb, SEG6_LOCAL_NH6, sizeof(struct in6_addr));
759 if (!nla)
760 return -EMSGSIZE;
761
762 memcpy(nla_data(nla), &slwt->nh6, sizeof(struct in6_addr));
763
764 return 0;
765 }
766
cmp_nla_nh6(struct seg6_local_lwt * a,struct seg6_local_lwt * b)767 static int cmp_nla_nh6(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
768 {
769 return memcmp(&a->nh6, &b->nh6, sizeof(struct in6_addr));
770 }
771
parse_nla_iif(struct nlattr ** attrs,struct seg6_local_lwt * slwt)772 static int parse_nla_iif(struct nlattr **attrs, struct seg6_local_lwt *slwt)
773 {
774 slwt->iif = nla_get_u32(attrs[SEG6_LOCAL_IIF]);
775
776 return 0;
777 }
778
put_nla_iif(struct sk_buff * skb,struct seg6_local_lwt * slwt)779 static int put_nla_iif(struct sk_buff *skb, struct seg6_local_lwt *slwt)
780 {
781 if (nla_put_u32(skb, SEG6_LOCAL_IIF, slwt->iif))
782 return -EMSGSIZE;
783
784 return 0;
785 }
786
cmp_nla_iif(struct seg6_local_lwt * a,struct seg6_local_lwt * b)787 static int cmp_nla_iif(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
788 {
789 if (a->iif != b->iif)
790 return 1;
791
792 return 0;
793 }
794
parse_nla_oif(struct nlattr ** attrs,struct seg6_local_lwt * slwt)795 static int parse_nla_oif(struct nlattr **attrs, struct seg6_local_lwt *slwt)
796 {
797 slwt->oif = nla_get_u32(attrs[SEG6_LOCAL_OIF]);
798
799 return 0;
800 }
801
put_nla_oif(struct sk_buff * skb,struct seg6_local_lwt * slwt)802 static int put_nla_oif(struct sk_buff *skb, struct seg6_local_lwt *slwt)
803 {
804 if (nla_put_u32(skb, SEG6_LOCAL_OIF, slwt->oif))
805 return -EMSGSIZE;
806
807 return 0;
808 }
809
cmp_nla_oif(struct seg6_local_lwt * a,struct seg6_local_lwt * b)810 static int cmp_nla_oif(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
811 {
812 if (a->oif != b->oif)
813 return 1;
814
815 return 0;
816 }
817
818 #define MAX_PROG_NAME 256
819 static const struct nla_policy bpf_prog_policy[SEG6_LOCAL_BPF_PROG_MAX + 1] = {
820 [SEG6_LOCAL_BPF_PROG] = { .type = NLA_U32, },
821 [SEG6_LOCAL_BPF_PROG_NAME] = { .type = NLA_NUL_STRING,
822 .len = MAX_PROG_NAME },
823 };
824
parse_nla_bpf(struct nlattr ** attrs,struct seg6_local_lwt * slwt)825 static int parse_nla_bpf(struct nlattr **attrs, struct seg6_local_lwt *slwt)
826 {
827 struct nlattr *tb[SEG6_LOCAL_BPF_PROG_MAX + 1];
828 struct bpf_prog *p;
829 int ret;
830 u32 fd;
831
832 ret = nla_parse_nested_deprecated(tb, SEG6_LOCAL_BPF_PROG_MAX,
833 attrs[SEG6_LOCAL_BPF],
834 bpf_prog_policy, NULL);
835 if (ret < 0)
836 return ret;
837
838 if (!tb[SEG6_LOCAL_BPF_PROG] || !tb[SEG6_LOCAL_BPF_PROG_NAME])
839 return -EINVAL;
840
841 slwt->bpf.name = nla_memdup(tb[SEG6_LOCAL_BPF_PROG_NAME], GFP_KERNEL);
842 if (!slwt->bpf.name)
843 return -ENOMEM;
844
845 fd = nla_get_u32(tb[SEG6_LOCAL_BPF_PROG]);
846 p = bpf_prog_get_type(fd, BPF_PROG_TYPE_LWT_SEG6LOCAL);
847 if (IS_ERR(p)) {
848 kfree(slwt->bpf.name);
849 return PTR_ERR(p);
850 }
851
852 slwt->bpf.prog = p;
853 return 0;
854 }
855
put_nla_bpf(struct sk_buff * skb,struct seg6_local_lwt * slwt)856 static int put_nla_bpf(struct sk_buff *skb, struct seg6_local_lwt *slwt)
857 {
858 struct nlattr *nest;
859
860 if (!slwt->bpf.prog)
861 return 0;
862
863 nest = nla_nest_start_noflag(skb, SEG6_LOCAL_BPF);
864 if (!nest)
865 return -EMSGSIZE;
866
867 if (nla_put_u32(skb, SEG6_LOCAL_BPF_PROG, slwt->bpf.prog->aux->id))
868 return -EMSGSIZE;
869
870 if (slwt->bpf.name &&
871 nla_put_string(skb, SEG6_LOCAL_BPF_PROG_NAME, slwt->bpf.name))
872 return -EMSGSIZE;
873
874 return nla_nest_end(skb, nest);
875 }
876
cmp_nla_bpf(struct seg6_local_lwt * a,struct seg6_local_lwt * b)877 static int cmp_nla_bpf(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
878 {
879 if (!a->bpf.name && !b->bpf.name)
880 return 0;
881
882 if (!a->bpf.name || !b->bpf.name)
883 return 1;
884
885 return strcmp(a->bpf.name, b->bpf.name);
886 }
887
888 struct seg6_action_param {
889 int (*parse)(struct nlattr **attrs, struct seg6_local_lwt *slwt);
890 int (*put)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
891 int (*cmp)(struct seg6_local_lwt *a, struct seg6_local_lwt *b);
892 };
893
894 static struct seg6_action_param seg6_action_params[SEG6_LOCAL_MAX + 1] = {
895 [SEG6_LOCAL_SRH] = { .parse = parse_nla_srh,
896 .put = put_nla_srh,
897 .cmp = cmp_nla_srh },
898
899 [SEG6_LOCAL_TABLE] = { .parse = parse_nla_table,
900 .put = put_nla_table,
901 .cmp = cmp_nla_table },
902
903 [SEG6_LOCAL_NH4] = { .parse = parse_nla_nh4,
904 .put = put_nla_nh4,
905 .cmp = cmp_nla_nh4 },
906
907 [SEG6_LOCAL_NH6] = { .parse = parse_nla_nh6,
908 .put = put_nla_nh6,
909 .cmp = cmp_nla_nh6 },
910
911 [SEG6_LOCAL_IIF] = { .parse = parse_nla_iif,
912 .put = put_nla_iif,
913 .cmp = cmp_nla_iif },
914
915 [SEG6_LOCAL_OIF] = { .parse = parse_nla_oif,
916 .put = put_nla_oif,
917 .cmp = cmp_nla_oif },
918
919 [SEG6_LOCAL_BPF] = { .parse = parse_nla_bpf,
920 .put = put_nla_bpf,
921 .cmp = cmp_nla_bpf },
922
923 };
924
parse_nla_action(struct nlattr ** attrs,struct seg6_local_lwt * slwt)925 static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)
926 {
927 struct seg6_action_param *param;
928 struct seg6_action_desc *desc;
929 int i, err;
930
931 desc = __get_action_desc(slwt->action);
932 if (!desc)
933 return -EINVAL;
934
935 if (!desc->input)
936 return -EOPNOTSUPP;
937
938 slwt->desc = desc;
939 slwt->headroom += desc->static_headroom;
940
941 for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
942 if (desc->attrs & (1 << i)) {
943 if (!attrs[i])
944 return -EINVAL;
945
946 param = &seg6_action_params[i];
947
948 err = param->parse(attrs, slwt);
949 if (err < 0)
950 return err;
951 }
952 }
953
954 return 0;
955 }
956
seg6_local_build_state(struct nlattr * nla,unsigned int family,const void * cfg,struct lwtunnel_state ** ts,struct netlink_ext_ack * extack)957 static int seg6_local_build_state(struct nlattr *nla, unsigned int family,
958 const void *cfg, struct lwtunnel_state **ts,
959 struct netlink_ext_ack *extack)
960 {
961 struct nlattr *tb[SEG6_LOCAL_MAX + 1];
962 struct lwtunnel_state *newts;
963 struct seg6_local_lwt *slwt;
964 int err;
965
966 if (family != AF_INET6)
967 return -EINVAL;
968
969 err = nla_parse_nested_deprecated(tb, SEG6_LOCAL_MAX, nla,
970 seg6_local_policy, extack);
971
972 if (err < 0)
973 return err;
974
975 if (!tb[SEG6_LOCAL_ACTION])
976 return -EINVAL;
977
978 newts = lwtunnel_state_alloc(sizeof(*slwt));
979 if (!newts)
980 return -ENOMEM;
981
982 slwt = seg6_local_lwtunnel(newts);
983 slwt->action = nla_get_u32(tb[SEG6_LOCAL_ACTION]);
984
985 err = parse_nla_action(tb, slwt);
986 if (err < 0)
987 goto out_free;
988
989 newts->type = LWTUNNEL_ENCAP_SEG6_LOCAL;
990 newts->flags = LWTUNNEL_STATE_INPUT_REDIRECT;
991 newts->headroom = slwt->headroom;
992
993 *ts = newts;
994
995 return 0;
996
997 out_free:
998 kfree(slwt->srh);
999 kfree(newts);
1000 return err;
1001 }
1002
seg6_local_destroy_state(struct lwtunnel_state * lwt)1003 static void seg6_local_destroy_state(struct lwtunnel_state *lwt)
1004 {
1005 struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
1006
1007 kfree(slwt->srh);
1008
1009 if (slwt->desc->attrs & (1 << SEG6_LOCAL_BPF)) {
1010 kfree(slwt->bpf.name);
1011 bpf_prog_put(slwt->bpf.prog);
1012 }
1013
1014 return;
1015 }
1016
seg6_local_fill_encap(struct sk_buff * skb,struct lwtunnel_state * lwt)1017 static int seg6_local_fill_encap(struct sk_buff *skb,
1018 struct lwtunnel_state *lwt)
1019 {
1020 struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
1021 struct seg6_action_param *param;
1022 int i, err;
1023
1024 if (nla_put_u32(skb, SEG6_LOCAL_ACTION, slwt->action))
1025 return -EMSGSIZE;
1026
1027 for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
1028 if (slwt->desc->attrs & (1 << i)) {
1029 param = &seg6_action_params[i];
1030 err = param->put(skb, slwt);
1031 if (err < 0)
1032 return err;
1033 }
1034 }
1035
1036 return 0;
1037 }
1038
seg6_local_get_encap_size(struct lwtunnel_state * lwt)1039 static int seg6_local_get_encap_size(struct lwtunnel_state *lwt)
1040 {
1041 struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
1042 unsigned long attrs;
1043 int nlsize;
1044
1045 nlsize = nla_total_size(4); /* action */
1046
1047 attrs = slwt->desc->attrs;
1048
1049 if (attrs & (1 << SEG6_LOCAL_SRH))
1050 nlsize += nla_total_size((slwt->srh->hdrlen + 1) << 3);
1051
1052 if (attrs & (1 << SEG6_LOCAL_TABLE))
1053 nlsize += nla_total_size(4);
1054
1055 if (attrs & (1 << SEG6_LOCAL_NH4))
1056 nlsize += nla_total_size(4);
1057
1058 if (attrs & (1 << SEG6_LOCAL_NH6))
1059 nlsize += nla_total_size(16);
1060
1061 if (attrs & (1 << SEG6_LOCAL_IIF))
1062 nlsize += nla_total_size(4);
1063
1064 if (attrs & (1 << SEG6_LOCAL_OIF))
1065 nlsize += nla_total_size(4);
1066
1067 if (attrs & (1 << SEG6_LOCAL_BPF))
1068 nlsize += nla_total_size(sizeof(struct nlattr)) +
1069 nla_total_size(MAX_PROG_NAME) +
1070 nla_total_size(4);
1071
1072 return nlsize;
1073 }
1074
seg6_local_cmp_encap(struct lwtunnel_state * a,struct lwtunnel_state * b)1075 static int seg6_local_cmp_encap(struct lwtunnel_state *a,
1076 struct lwtunnel_state *b)
1077 {
1078 struct seg6_local_lwt *slwt_a, *slwt_b;
1079 struct seg6_action_param *param;
1080 int i;
1081
1082 slwt_a = seg6_local_lwtunnel(a);
1083 slwt_b = seg6_local_lwtunnel(b);
1084
1085 if (slwt_a->action != slwt_b->action)
1086 return 1;
1087
1088 if (slwt_a->desc->attrs != slwt_b->desc->attrs)
1089 return 1;
1090
1091 for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
1092 if (slwt_a->desc->attrs & (1 << i)) {
1093 param = &seg6_action_params[i];
1094 if (param->cmp(slwt_a, slwt_b))
1095 return 1;
1096 }
1097 }
1098
1099 return 0;
1100 }
1101
1102 static const struct lwtunnel_encap_ops seg6_local_ops = {
1103 .build_state = seg6_local_build_state,
1104 .destroy_state = seg6_local_destroy_state,
1105 .input = seg6_local_input,
1106 .fill_encap = seg6_local_fill_encap,
1107 .get_encap_size = seg6_local_get_encap_size,
1108 .cmp_encap = seg6_local_cmp_encap,
1109 .owner = THIS_MODULE,
1110 };
1111
seg6_local_init(void)1112 int __init seg6_local_init(void)
1113 {
1114 return lwtunnel_encap_add_ops(&seg6_local_ops,
1115 LWTUNNEL_ENCAP_SEG6_LOCAL);
1116 }
1117
seg6_local_exit(void)1118 void seg6_local_exit(void)
1119 {
1120 lwtunnel_encap_del_ops(&seg6_local_ops, LWTUNNEL_ENCAP_SEG6_LOCAL);
1121 }
1122
