1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
3 */
4
5 #include <linux/filter.h>
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/skbuff.h>
9 #include <linux/types.h>
10 #include <linux/bpf.h>
11 #include <net/lwtunnel.h>
12 #include <net/gre.h>
13 #include <net/ip6_route.h>
14 #include <net/ipv6_stubs.h>
15
16 struct bpf_lwt_prog {
17 struct bpf_prog *prog;
18 char *name;
19 };
20
21 struct bpf_lwt {
22 struct bpf_lwt_prog in;
23 struct bpf_lwt_prog out;
24 struct bpf_lwt_prog xmit;
25 int family;
26 };
27
28 #define MAX_PROG_NAME 256
29
bpf_lwt_lwtunnel(struct lwtunnel_state * lwt)30 static inline struct bpf_lwt *bpf_lwt_lwtunnel(struct lwtunnel_state *lwt)
31 {
32 return (struct bpf_lwt *)lwt->data;
33 }
34
35 #define NO_REDIRECT false
36 #define CAN_REDIRECT true
37
run_lwt_bpf(struct sk_buff * skb,struct bpf_lwt_prog * lwt,struct dst_entry * dst,bool can_redirect)38 static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
39 struct dst_entry *dst, bool can_redirect)
40 {
41 int ret;
42
43 /* Migration disable and BH disable are needed to protect per-cpu
44 * redirect_info between BPF prog and skb_do_redirect().
45 */
46 migrate_disable();
47 local_bh_disable();
48 bpf_compute_data_pointers(skb);
49 ret = bpf_prog_run_save_cb(lwt->prog, skb);
50
51 switch (ret) {
52 case BPF_OK:
53 case BPF_LWT_REROUTE:
54 break;
55
56 case BPF_REDIRECT:
57 if (unlikely(!can_redirect)) {
58 pr_warn_once("Illegal redirect return code in prog %s\n",
59 lwt->name ? : "<unknown>");
60 ret = BPF_OK;
61 } else {
62 skb_reset_mac_header(skb);
63 skb_do_redirect(skb);
64 ret = BPF_REDIRECT;
65 }
66 break;
67
68 case BPF_DROP:
69 kfree_skb(skb);
70 ret = -EPERM;
71 break;
72
73 default:
74 pr_warn_once("bpf-lwt: Illegal return value %u, expect packet loss\n", ret);
75 kfree_skb(skb);
76 ret = -EINVAL;
77 break;
78 }
79
80 local_bh_enable();
81 migrate_enable();
82
83 return ret;
84 }
85
bpf_lwt_input_reroute(struct sk_buff * skb)86 static int bpf_lwt_input_reroute(struct sk_buff *skb)
87 {
88 int err = -EINVAL;
89
90 if (skb->protocol == htons(ETH_P_IP)) {
91 struct net_device *dev = skb_dst(skb)->dev;
92 struct iphdr *iph = ip_hdr(skb);
93
94 dev_hold(dev);
95 skb_dst_drop(skb);
96 err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
97 iph->tos, dev);
98 dev_put(dev);
99 } else if (skb->protocol == htons(ETH_P_IPV6)) {
100 skb_dst_drop(skb);
101 err = ipv6_stub->ipv6_route_input(skb);
102 } else {
103 err = -EAFNOSUPPORT;
104 }
105
106 if (err)
107 goto err;
108 return dst_input(skb);
109
110 err:
111 kfree_skb(skb);
112 return err;
113 }
114
bpf_input(struct sk_buff * skb)115 static int bpf_input(struct sk_buff *skb)
116 {
117 struct dst_entry *dst = skb_dst(skb);
118 struct bpf_lwt *bpf;
119 int ret;
120
121 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
122 if (bpf->in.prog) {
123 ret = run_lwt_bpf(skb, &bpf->in, dst, NO_REDIRECT);
124 if (ret < 0)
125 return ret;
126 if (ret == BPF_LWT_REROUTE)
127 return bpf_lwt_input_reroute(skb);
128 }
129
130 if (unlikely(!dst->lwtstate->orig_input)) {
131 kfree_skb(skb);
132 return -EINVAL;
133 }
134
135 return dst->lwtstate->orig_input(skb);
136 }
137
bpf_output(struct net * net,struct sock * sk,struct sk_buff * skb)138 static int bpf_output(struct net *net, struct sock *sk, struct sk_buff *skb)
139 {
140 struct dst_entry *dst = skb_dst(skb);
141 struct bpf_lwt *bpf;
142 int ret;
143
144 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
145 if (bpf->out.prog) {
146 ret = run_lwt_bpf(skb, &bpf->out, dst, NO_REDIRECT);
147 if (ret < 0)
148 return ret;
149 }
150
151 if (unlikely(!dst->lwtstate->orig_output)) {
152 pr_warn_once("orig_output not set on dst for prog %s\n",
153 bpf->out.name);
154 kfree_skb(skb);
155 return -EINVAL;
156 }
157
158 return dst->lwtstate->orig_output(net, sk, skb);
159 }
160
xmit_check_hhlen(struct sk_buff * skb,int hh_len)161 static int xmit_check_hhlen(struct sk_buff *skb, int hh_len)
162 {
163 if (skb_headroom(skb) < hh_len) {
164 int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
165
166 if (pskb_expand_head(skb, nhead, 0, GFP_ATOMIC))
167 return -ENOMEM;
168 }
169
170 return 0;
171 }
172
bpf_lwt_xmit_reroute(struct sk_buff * skb)173 static int bpf_lwt_xmit_reroute(struct sk_buff *skb)
174 {
175 struct net_device *l3mdev = l3mdev_master_dev_rcu(skb_dst(skb)->dev);
176 int oif = l3mdev ? l3mdev->ifindex : 0;
177 struct dst_entry *dst = NULL;
178 int err = -EAFNOSUPPORT;
179 struct sock *sk;
180 struct net *net;
181 bool ipv4;
182
183 if (skb->protocol == htons(ETH_P_IP))
184 ipv4 = true;
185 else if (skb->protocol == htons(ETH_P_IPV6))
186 ipv4 = false;
187 else
188 goto err;
189
190 sk = sk_to_full_sk(skb->sk);
191 if (sk) {
192 if (sk->sk_bound_dev_if)
193 oif = sk->sk_bound_dev_if;
194 net = sock_net(sk);
195 } else {
196 net = dev_net(skb_dst(skb)->dev);
197 }
198
199 if (ipv4) {
200 struct iphdr *iph = ip_hdr(skb);
201 struct flowi4 fl4 = {};
202 struct rtable *rt;
203
204 fl4.flowi4_oif = oif;
205 fl4.flowi4_mark = skb->mark;
206 fl4.flowi4_uid = sock_net_uid(net, sk);
207 fl4.flowi4_tos = RT_TOS(iph->tos);
208 fl4.flowi4_flags = FLOWI_FLAG_ANYSRC;
209 fl4.flowi4_proto = iph->protocol;
210 fl4.daddr = iph->daddr;
211 fl4.saddr = iph->saddr;
212
213 rt = ip_route_output_key(net, &fl4);
214 if (IS_ERR(rt)) {
215 err = PTR_ERR(rt);
216 goto err;
217 }
218 dst = &rt->dst;
219 } else {
220 struct ipv6hdr *iph6 = ipv6_hdr(skb);
221 struct flowi6 fl6 = {};
222
223 fl6.flowi6_oif = oif;
224 fl6.flowi6_mark = skb->mark;
225 fl6.flowi6_uid = sock_net_uid(net, sk);
226 fl6.flowlabel = ip6_flowinfo(iph6);
227 fl6.flowi6_proto = iph6->nexthdr;
228 fl6.daddr = iph6->daddr;
229 fl6.saddr = iph6->saddr;
230
231 dst = ipv6_stub->ipv6_dst_lookup_flow(net, skb->sk, &fl6, NULL);
232 if (IS_ERR(dst)) {
233 err = PTR_ERR(dst);
234 goto err;
235 }
236 }
237 if (unlikely(dst->error)) {
238 err = dst->error;
239 dst_release(dst);
240 goto err;
241 }
242
243 /* Although skb header was reserved in bpf_lwt_push_ip_encap(), it
244 * was done for the previous dst, so we are doing it here again, in
245 * case the new dst needs much more space. The call below is a noop
246 * if there is enough header space in skb.
247 */
248 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
249 if (unlikely(err))
250 goto err;
251
252 skb_dst_drop(skb);
253 skb_dst_set(skb, dst);
254
255 err = dst_output(dev_net(skb_dst(skb)->dev), skb->sk, skb);
256 if (unlikely(err))
257 return net_xmit_errno(err);
258
259 /* ip[6]_finish_output2 understand LWTUNNEL_XMIT_DONE */
260 return LWTUNNEL_XMIT_DONE;
261
262 err:
263 kfree_skb(skb);
264 return err;
265 }
266
bpf_xmit(struct sk_buff * skb)267 static int bpf_xmit(struct sk_buff *skb)
268 {
269 struct dst_entry *dst = skb_dst(skb);
270 struct bpf_lwt *bpf;
271
272 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
273 if (bpf->xmit.prog) {
274 int hh_len = dst->dev->hard_header_len;
275 __be16 proto = skb->protocol;
276 int ret;
277
278 ret = run_lwt_bpf(skb, &bpf->xmit, dst, CAN_REDIRECT);
279 switch (ret) {
280 case BPF_OK:
281 /* If the header changed, e.g. via bpf_lwt_push_encap,
282 * BPF_LWT_REROUTE below should have been used if the
283 * protocol was also changed.
284 */
285 if (skb->protocol != proto) {
286 kfree_skb(skb);
287 return -EINVAL;
288 }
289 /* If the header was expanded, headroom might be too
290 * small for L2 header to come, expand as needed.
291 */
292 ret = xmit_check_hhlen(skb, hh_len);
293 if (unlikely(ret))
294 return ret;
295
296 return LWTUNNEL_XMIT_CONTINUE;
297 case BPF_REDIRECT:
298 return LWTUNNEL_XMIT_DONE;
299 case BPF_LWT_REROUTE:
300 return bpf_lwt_xmit_reroute(skb);
301 default:
302 return ret;
303 }
304 }
305
306 return LWTUNNEL_XMIT_CONTINUE;
307 }
308
bpf_lwt_prog_destroy(struct bpf_lwt_prog * prog)309 static void bpf_lwt_prog_destroy(struct bpf_lwt_prog *prog)
310 {
311 if (prog->prog)
312 bpf_prog_put(prog->prog);
313
314 kfree(prog->name);
315 }
316
bpf_destroy_state(struct lwtunnel_state * lwt)317 static void bpf_destroy_state(struct lwtunnel_state *lwt)
318 {
319 struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt);
320
321 bpf_lwt_prog_destroy(&bpf->in);
322 bpf_lwt_prog_destroy(&bpf->out);
323 bpf_lwt_prog_destroy(&bpf->xmit);
324 }
325
326 static const struct nla_policy bpf_prog_policy[LWT_BPF_PROG_MAX + 1] = {
327 [LWT_BPF_PROG_FD] = { .type = NLA_U32, },
328 [LWT_BPF_PROG_NAME] = { .type = NLA_NUL_STRING,
329 .len = MAX_PROG_NAME },
330 };
331
bpf_parse_prog(struct nlattr * attr,struct bpf_lwt_prog * prog,enum bpf_prog_type type)332 static int bpf_parse_prog(struct nlattr *attr, struct bpf_lwt_prog *prog,
333 enum bpf_prog_type type)
334 {
335 struct nlattr *tb[LWT_BPF_PROG_MAX + 1];
336 struct bpf_prog *p;
337 int ret;
338 u32 fd;
339
340 ret = nla_parse_nested_deprecated(tb, LWT_BPF_PROG_MAX, attr,
341 bpf_prog_policy, NULL);
342 if (ret < 0)
343 return ret;
344
345 if (!tb[LWT_BPF_PROG_FD] || !tb[LWT_BPF_PROG_NAME])
346 return -EINVAL;
347
348 prog->name = nla_memdup(tb[LWT_BPF_PROG_NAME], GFP_ATOMIC);
349 if (!prog->name)
350 return -ENOMEM;
351
352 fd = nla_get_u32(tb[LWT_BPF_PROG_FD]);
353 p = bpf_prog_get_type(fd, type);
354 if (IS_ERR(p))
355 return PTR_ERR(p);
356
357 prog->prog = p;
358
359 return 0;
360 }
361
362 static const struct nla_policy bpf_nl_policy[LWT_BPF_MAX + 1] = {
363 [LWT_BPF_IN] = { .type = NLA_NESTED, },
364 [LWT_BPF_OUT] = { .type = NLA_NESTED, },
365 [LWT_BPF_XMIT] = { .type = NLA_NESTED, },
366 [LWT_BPF_XMIT_HEADROOM] = { .type = NLA_U32 },
367 };
368
bpf_build_state(struct net * net,struct nlattr * nla,unsigned int family,const void * cfg,struct lwtunnel_state ** ts,struct netlink_ext_ack * extack)369 static int bpf_build_state(struct net *net, struct nlattr *nla,
370 unsigned int family, const void *cfg,
371 struct lwtunnel_state **ts,
372 struct netlink_ext_ack *extack)
373 {
374 struct nlattr *tb[LWT_BPF_MAX + 1];
375 struct lwtunnel_state *newts;
376 struct bpf_lwt *bpf;
377 int ret;
378
379 if (family != AF_INET && family != AF_INET6)
380 return -EAFNOSUPPORT;
381
382 ret = nla_parse_nested_deprecated(tb, LWT_BPF_MAX, nla, bpf_nl_policy,
383 extack);
384 if (ret < 0)
385 return ret;
386
387 if (!tb[LWT_BPF_IN] && !tb[LWT_BPF_OUT] && !tb[LWT_BPF_XMIT])
388 return -EINVAL;
389
390 newts = lwtunnel_state_alloc(sizeof(*bpf));
391 if (!newts)
392 return -ENOMEM;
393
394 newts->type = LWTUNNEL_ENCAP_BPF;
395 bpf = bpf_lwt_lwtunnel(newts);
396
397 if (tb[LWT_BPF_IN]) {
398 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
399 ret = bpf_parse_prog(tb[LWT_BPF_IN], &bpf->in,
400 BPF_PROG_TYPE_LWT_IN);
401 if (ret < 0)
402 goto errout;
403 }
404
405 if (tb[LWT_BPF_OUT]) {
406 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
407 ret = bpf_parse_prog(tb[LWT_BPF_OUT], &bpf->out,
408 BPF_PROG_TYPE_LWT_OUT);
409 if (ret < 0)
410 goto errout;
411 }
412
413 if (tb[LWT_BPF_XMIT]) {
414 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
415 ret = bpf_parse_prog(tb[LWT_BPF_XMIT], &bpf->xmit,
416 BPF_PROG_TYPE_LWT_XMIT);
417 if (ret < 0)
418 goto errout;
419 }
420
421 if (tb[LWT_BPF_XMIT_HEADROOM]) {
422 u32 headroom = nla_get_u32(tb[LWT_BPF_XMIT_HEADROOM]);
423
424 if (headroom > LWT_BPF_MAX_HEADROOM) {
425 ret = -ERANGE;
426 goto errout;
427 }
428
429 newts->headroom = headroom;
430 }
431
432 bpf->family = family;
433 *ts = newts;
434
435 return 0;
436
437 errout:
438 bpf_destroy_state(newts);
439 kfree(newts);
440 return ret;
441 }
442
bpf_fill_lwt_prog(struct sk_buff * skb,int attr,struct bpf_lwt_prog * prog)443 static int bpf_fill_lwt_prog(struct sk_buff *skb, int attr,
444 struct bpf_lwt_prog *prog)
445 {
446 struct nlattr *nest;
447
448 if (!prog->prog)
449 return 0;
450
451 nest = nla_nest_start_noflag(skb, attr);
452 if (!nest)
453 return -EMSGSIZE;
454
455 if (prog->name &&
456 nla_put_string(skb, LWT_BPF_PROG_NAME, prog->name))
457 return -EMSGSIZE;
458
459 return nla_nest_end(skb, nest);
460 }
461
bpf_fill_encap_info(struct sk_buff * skb,struct lwtunnel_state * lwt)462 static int bpf_fill_encap_info(struct sk_buff *skb, struct lwtunnel_state *lwt)
463 {
464 struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt);
465
466 if (bpf_fill_lwt_prog(skb, LWT_BPF_IN, &bpf->in) < 0 ||
467 bpf_fill_lwt_prog(skb, LWT_BPF_OUT, &bpf->out) < 0 ||
468 bpf_fill_lwt_prog(skb, LWT_BPF_XMIT, &bpf->xmit) < 0)
469 return -EMSGSIZE;
470
471 return 0;
472 }
473
bpf_encap_nlsize(struct lwtunnel_state * lwtstate)474 static int bpf_encap_nlsize(struct lwtunnel_state *lwtstate)
475 {
476 int nest_len = nla_total_size(sizeof(struct nlattr)) +
477 nla_total_size(MAX_PROG_NAME) + /* LWT_BPF_PROG_NAME */
478 0;
479
480 return nest_len + /* LWT_BPF_IN */
481 nest_len + /* LWT_BPF_OUT */
482 nest_len + /* LWT_BPF_XMIT */
483 0;
484 }
485
bpf_lwt_prog_cmp(struct bpf_lwt_prog * a,struct bpf_lwt_prog * b)486 static int bpf_lwt_prog_cmp(struct bpf_lwt_prog *a, struct bpf_lwt_prog *b)
487 {
488 /* FIXME:
489 * The LWT state is currently rebuilt for delete requests which
490 * results in a new bpf_prog instance. Comparing names for now.
491 */
492 if (!a->name && !b->name)
493 return 0;
494
495 if (!a->name || !b->name)
496 return 1;
497
498 return strcmp(a->name, b->name);
499 }
500
bpf_encap_cmp(struct lwtunnel_state * a,struct lwtunnel_state * b)501 static int bpf_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
502 {
503 struct bpf_lwt *a_bpf = bpf_lwt_lwtunnel(a);
504 struct bpf_lwt *b_bpf = bpf_lwt_lwtunnel(b);
505
506 return bpf_lwt_prog_cmp(&a_bpf->in, &b_bpf->in) ||
507 bpf_lwt_prog_cmp(&a_bpf->out, &b_bpf->out) ||
508 bpf_lwt_prog_cmp(&a_bpf->xmit, &b_bpf->xmit);
509 }
510
511 static const struct lwtunnel_encap_ops bpf_encap_ops = {
512 .build_state = bpf_build_state,
513 .destroy_state = bpf_destroy_state,
514 .input = bpf_input,
515 .output = bpf_output,
516 .xmit = bpf_xmit,
517 .fill_encap = bpf_fill_encap_info,
518 .get_encap_size = bpf_encap_nlsize,
519 .cmp_encap = bpf_encap_cmp,
520 .owner = THIS_MODULE,
521 };
522
handle_gso_type(struct sk_buff * skb,unsigned int gso_type,int encap_len)523 static int handle_gso_type(struct sk_buff *skb, unsigned int gso_type,
524 int encap_len)
525 {
526 struct skb_shared_info *shinfo = skb_shinfo(skb);
527
528 gso_type |= SKB_GSO_DODGY;
529 shinfo->gso_type |= gso_type;
530 skb_decrease_gso_size(shinfo, encap_len);
531 shinfo->gso_segs = 0;
532 return 0;
533 }
534
handle_gso_encap(struct sk_buff * skb,bool ipv4,int encap_len)535 static int handle_gso_encap(struct sk_buff *skb, bool ipv4, int encap_len)
536 {
537 int next_hdr_offset;
538 void *next_hdr;
539 __u8 protocol;
540
541 /* SCTP and UDP_L4 gso need more nuanced handling than what
542 * handle_gso_type() does above: skb_decrease_gso_size() is not enough.
543 * So at the moment only TCP GSO packets are let through.
544 */
545 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
546 return -ENOTSUPP;
547
548 if (ipv4) {
549 protocol = ip_hdr(skb)->protocol;
550 next_hdr_offset = sizeof(struct iphdr);
551 next_hdr = skb_network_header(skb) + next_hdr_offset;
552 } else {
553 protocol = ipv6_hdr(skb)->nexthdr;
554 next_hdr_offset = sizeof(struct ipv6hdr);
555 next_hdr = skb_network_header(skb) + next_hdr_offset;
556 }
557
558 switch (protocol) {
559 case IPPROTO_GRE:
560 next_hdr_offset += sizeof(struct gre_base_hdr);
561 if (next_hdr_offset > encap_len)
562 return -EINVAL;
563
564 if (((struct gre_base_hdr *)next_hdr)->flags & GRE_CSUM)
565 return handle_gso_type(skb, SKB_GSO_GRE_CSUM,
566 encap_len);
567 return handle_gso_type(skb, SKB_GSO_GRE, encap_len);
568
569 case IPPROTO_UDP:
570 next_hdr_offset += sizeof(struct udphdr);
571 if (next_hdr_offset > encap_len)
572 return -EINVAL;
573
574 if (((struct udphdr *)next_hdr)->check)
575 return handle_gso_type(skb, SKB_GSO_UDP_TUNNEL_CSUM,
576 encap_len);
577 return handle_gso_type(skb, SKB_GSO_UDP_TUNNEL, encap_len);
578
579 case IPPROTO_IP:
580 case IPPROTO_IPV6:
581 if (ipv4)
582 return handle_gso_type(skb, SKB_GSO_IPXIP4, encap_len);
583 else
584 return handle_gso_type(skb, SKB_GSO_IPXIP6, encap_len);
585
586 default:
587 return -EPROTONOSUPPORT;
588 }
589 }
590
bpf_lwt_push_ip_encap(struct sk_buff * skb,void * hdr,u32 len,bool ingress)591 int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len, bool ingress)
592 {
593 struct iphdr *iph;
594 bool ipv4;
595 int err;
596
597 if (unlikely(len < sizeof(struct iphdr) || len > LWT_BPF_MAX_HEADROOM))
598 return -EINVAL;
599
600 /* validate protocol and length */
601 iph = (struct iphdr *)hdr;
602 if (iph->version == 4) {
603 ipv4 = true;
604 if (unlikely(len < iph->ihl * 4))
605 return -EINVAL;
606 } else if (iph->version == 6) {
607 ipv4 = false;
608 if (unlikely(len < sizeof(struct ipv6hdr)))
609 return -EINVAL;
610 } else {
611 return -EINVAL;
612 }
613
614 if (ingress)
615 err = skb_cow_head(skb, len + skb->mac_len);
616 else
617 err = skb_cow_head(skb,
618 len + LL_RESERVED_SPACE(skb_dst(skb)->dev));
619 if (unlikely(err))
620 return err;
621
622 /* push the encap headers and fix pointers */
623 skb_reset_inner_headers(skb);
624 skb_reset_inner_mac_header(skb); /* mac header is not yet set */
625 skb_set_inner_protocol(skb, skb->protocol);
626 skb->encapsulation = 1;
627 skb_push(skb, len);
628 if (ingress)
629 skb_postpush_rcsum(skb, iph, len);
630 skb_reset_network_header(skb);
631 memcpy(skb_network_header(skb), hdr, len);
632 bpf_compute_data_pointers(skb);
633 skb_clear_hash(skb);
634
635 if (ipv4) {
636 skb->protocol = htons(ETH_P_IP);
637 iph = ip_hdr(skb);
638
639 if (!iph->check)
640 iph->check = ip_fast_csum((unsigned char *)iph,
641 iph->ihl);
642 } else {
643 skb->protocol = htons(ETH_P_IPV6);
644 }
645
646 if (skb_is_gso(skb))
647 return handle_gso_encap(skb, ipv4, len);
648
649 return 0;
650 }
651
bpf_lwt_init(void)652 static int __init bpf_lwt_init(void)
653 {
654 return lwtunnel_encap_add_ops(&bpf_encap_ops, LWTUNNEL_ENCAP_BPF);
655 }
656
657 subsys_initcall(bpf_lwt_init)
658