1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/module.h>
3 #include <linux/errno.h>
4 #include <linux/socket.h>
5 #include <linux/skbuff.h>
6 #include <linux/ip.h>
7 #include <linux/icmp.h>
8 #include <linux/udp.h>
9 #include <linux/types.h>
10 #include <linux/kernel.h>
11 #include <net/genetlink.h>
12 #include <net/gue.h>
13 #include <net/fou.h>
14 #include <net/ip.h>
15 #include <net/protocol.h>
16 #include <net/udp.h>
17 #include <net/udp_tunnel.h>
18 #include <net/xfrm.h>
19 #include <uapi/linux/fou.h>
20 #include <uapi/linux/genetlink.h>
21
22 struct fou {
23 struct socket *sock;
24 u8 protocol;
25 u8 flags;
26 __be16 port;
27 u8 family;
28 u16 type;
29 struct list_head list;
30 struct rcu_head rcu;
31 };
32
33 #define FOU_F_REMCSUM_NOPARTIAL BIT(0)
34
35 struct fou_cfg {
36 u16 type;
37 u8 protocol;
38 u8 flags;
39 struct udp_port_cfg udp_config;
40 };
41
42 static unsigned int fou_net_id;
43
44 struct fou_net {
45 struct list_head fou_list;
46 struct mutex fou_lock;
47 };
48
fou_from_sock(struct sock * sk)49 static inline struct fou *fou_from_sock(struct sock *sk)
50 {
51 return sk->sk_user_data;
52 }
53
fou_recv_pull(struct sk_buff * skb,struct fou * fou,size_t len)54 static int fou_recv_pull(struct sk_buff *skb, struct fou *fou, size_t len)
55 {
56 /* Remove 'len' bytes from the packet (UDP header and
57 * FOU header if present).
58 */
59 if (fou->family == AF_INET)
60 ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(skb)->tot_len) - len);
61 else
62 ipv6_hdr(skb)->payload_len =
63 htons(ntohs(ipv6_hdr(skb)->payload_len) - len);
64
65 __skb_pull(skb, len);
66 skb_postpull_rcsum(skb, udp_hdr(skb), len);
67 skb_reset_transport_header(skb);
68 return iptunnel_pull_offloads(skb);
69 }
70
fou_udp_recv(struct sock * sk,struct sk_buff * skb)71 static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
72 {
73 struct fou *fou = fou_from_sock(sk);
74
75 if (!fou)
76 return 1;
77
78 if (fou_recv_pull(skb, fou, sizeof(struct udphdr)))
79 goto drop;
80
81 return -fou->protocol;
82
83 drop:
84 kfree_skb(skb);
85 return 0;
86 }
87
gue_remcsum(struct sk_buff * skb,struct guehdr * guehdr,void * data,size_t hdrlen,u8 ipproto,bool nopartial)88 static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
89 void *data, size_t hdrlen, u8 ipproto,
90 bool nopartial)
91 {
92 __be16 *pd = data;
93 size_t start = ntohs(pd[0]);
94 size_t offset = ntohs(pd[1]);
95 size_t plen = sizeof(struct udphdr) + hdrlen +
96 max_t(size_t, offset + sizeof(u16), start);
97
98 if (skb->remcsum_offload)
99 return guehdr;
100
101 if (!pskb_may_pull(skb, plen))
102 return NULL;
103 guehdr = (struct guehdr *)&udp_hdr(skb)[1];
104
105 skb_remcsum_process(skb, (void *)guehdr + hdrlen,
106 start, offset, nopartial);
107
108 return guehdr;
109 }
110
gue_control_message(struct sk_buff * skb,struct guehdr * guehdr)111 static int gue_control_message(struct sk_buff *skb, struct guehdr *guehdr)
112 {
113 /* No support yet */
114 kfree_skb(skb);
115 return 0;
116 }
117
gue_udp_recv(struct sock * sk,struct sk_buff * skb)118 static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
119 {
120 struct fou *fou = fou_from_sock(sk);
121 size_t len, optlen, hdrlen;
122 struct guehdr *guehdr;
123 void *data;
124 u16 doffset = 0;
125 u8 proto_ctype;
126
127 if (!fou)
128 return 1;
129
130 len = sizeof(struct udphdr) + sizeof(struct guehdr);
131 if (!pskb_may_pull(skb, len))
132 goto drop;
133
134 guehdr = (struct guehdr *)&udp_hdr(skb)[1];
135
136 switch (guehdr->version) {
137 case 0: /* Full GUE header present */
138 break;
139
140 case 1: {
141 /* Direct encapsulation of IPv4 or IPv6 */
142
143 int prot;
144
145 switch (((struct iphdr *)guehdr)->version) {
146 case 4:
147 prot = IPPROTO_IPIP;
148 break;
149 case 6:
150 prot = IPPROTO_IPV6;
151 break;
152 default:
153 goto drop;
154 }
155
156 if (fou_recv_pull(skb, fou, sizeof(struct udphdr)))
157 goto drop;
158
159 return -prot;
160 }
161
162 default: /* Undefined version */
163 goto drop;
164 }
165
166 optlen = guehdr->hlen << 2;
167 len += optlen;
168
169 if (!pskb_may_pull(skb, len))
170 goto drop;
171
172 /* guehdr may change after pull */
173 guehdr = (struct guehdr *)&udp_hdr(skb)[1];
174
175 if (validate_gue_flags(guehdr, optlen))
176 goto drop;
177
178 hdrlen = sizeof(struct guehdr) + optlen;
179
180 if (fou->family == AF_INET)
181 ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(skb)->tot_len) - len);
182 else
183 ipv6_hdr(skb)->payload_len =
184 htons(ntohs(ipv6_hdr(skb)->payload_len) - len);
185
186 /* Pull csum through the guehdr now . This can be used if
187 * there is a remote checksum offload.
188 */
189 skb_postpull_rcsum(skb, udp_hdr(skb), len);
190
191 data = &guehdr[1];
192
193 if (guehdr->flags & GUE_FLAG_PRIV) {
194 __be32 flags = *(__be32 *)(data + doffset);
195
196 doffset += GUE_LEN_PRIV;
197
198 if (flags & GUE_PFLAG_REMCSUM) {
199 guehdr = gue_remcsum(skb, guehdr, data + doffset,
200 hdrlen, guehdr->proto_ctype,
201 !!(fou->flags &
202 FOU_F_REMCSUM_NOPARTIAL));
203 if (!guehdr)
204 goto drop;
205
206 data = &guehdr[1];
207
208 doffset += GUE_PLEN_REMCSUM;
209 }
210 }
211
212 if (unlikely(guehdr->control))
213 return gue_control_message(skb, guehdr);
214
215 proto_ctype = guehdr->proto_ctype;
216 __skb_pull(skb, sizeof(struct udphdr) + hdrlen);
217 skb_reset_transport_header(skb);
218
219 if (iptunnel_pull_offloads(skb))
220 goto drop;
221
222 return -proto_ctype;
223
224 drop:
225 kfree_skb(skb);
226 return 0;
227 }
228
fou_gro_receive(struct sock * sk,struct list_head * head,struct sk_buff * skb)229 static struct sk_buff *fou_gro_receive(struct sock *sk,
230 struct list_head *head,
231 struct sk_buff *skb)
232 {
233 const struct net_offload __rcu **offloads;
234 u8 proto = fou_from_sock(sk)->protocol;
235 const struct net_offload *ops;
236 struct sk_buff *pp = NULL;
237
238 /* We can clear the encap_mark for FOU as we are essentially doing
239 * one of two possible things. We are either adding an L4 tunnel
240 * header to the outer L3 tunnel header, or we are simply
241 * treating the GRE tunnel header as though it is a UDP protocol
242 * specific header such as VXLAN or GENEVE.
243 */
244 NAPI_GRO_CB(skb)->encap_mark = 0;
245
246 /* Flag this frame as already having an outer encap header */
247 NAPI_GRO_CB(skb)->is_fou = 1;
248
249 rcu_read_lock();
250 offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
251 ops = rcu_dereference(offloads[proto]);
252 if (!ops || !ops->callbacks.gro_receive)
253 goto out_unlock;
254
255 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
256
257 out_unlock:
258 rcu_read_unlock();
259
260 return pp;
261 }
262
fou_gro_complete(struct sock * sk,struct sk_buff * skb,int nhoff)263 static int fou_gro_complete(struct sock *sk, struct sk_buff *skb,
264 int nhoff)
265 {
266 const struct net_offload __rcu **offloads;
267 u8 proto = fou_from_sock(sk)->protocol;
268 const struct net_offload *ops;
269 int err = -ENOSYS;
270
271 rcu_read_lock();
272 offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
273 ops = rcu_dereference(offloads[proto]);
274 if (WARN_ON(!ops || !ops->callbacks.gro_complete))
275 goto out_unlock;
276
277 err = ops->callbacks.gro_complete(skb, nhoff);
278
279 skb_set_inner_mac_header(skb, nhoff);
280
281 out_unlock:
282 rcu_read_unlock();
283
284 return err;
285 }
286
gue_gro_remcsum(struct sk_buff * skb,unsigned int off,struct guehdr * guehdr,void * data,size_t hdrlen,struct gro_remcsum * grc,bool nopartial)287 static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
288 struct guehdr *guehdr, void *data,
289 size_t hdrlen, struct gro_remcsum *grc,
290 bool nopartial)
291 {
292 __be16 *pd = data;
293 size_t start = ntohs(pd[0]);
294 size_t offset = ntohs(pd[1]);
295
296 if (skb->remcsum_offload)
297 return guehdr;
298
299 if (!NAPI_GRO_CB(skb)->csum_valid)
300 return NULL;
301
302 guehdr = skb_gro_remcsum_process(skb, (void *)guehdr, off, hdrlen,
303 start, offset, grc, nopartial);
304
305 skb->remcsum_offload = 1;
306
307 return guehdr;
308 }
309
gue_gro_receive(struct sock * sk,struct list_head * head,struct sk_buff * skb)310 static struct sk_buff *gue_gro_receive(struct sock *sk,
311 struct list_head *head,
312 struct sk_buff *skb)
313 {
314 const struct net_offload __rcu **offloads;
315 const struct net_offload *ops;
316 struct sk_buff *pp = NULL;
317 struct sk_buff *p;
318 struct guehdr *guehdr;
319 size_t len, optlen, hdrlen, off;
320 void *data;
321 u16 doffset = 0;
322 int flush = 1;
323 struct fou *fou = fou_from_sock(sk);
324 struct gro_remcsum grc;
325 u8 proto;
326
327 skb_gro_remcsum_init(&grc);
328
329 off = skb_gro_offset(skb);
330 len = off + sizeof(*guehdr);
331
332 guehdr = skb_gro_header_fast(skb, off);
333 if (skb_gro_header_hard(skb, len)) {
334 guehdr = skb_gro_header_slow(skb, len, off);
335 if (unlikely(!guehdr))
336 goto out;
337 }
338
339 switch (guehdr->version) {
340 case 0:
341 break;
342 case 1:
343 switch (((struct iphdr *)guehdr)->version) {
344 case 4:
345 proto = IPPROTO_IPIP;
346 break;
347 case 6:
348 proto = IPPROTO_IPV6;
349 break;
350 default:
351 goto out;
352 }
353 goto next_proto;
354 default:
355 goto out;
356 }
357
358 optlen = guehdr->hlen << 2;
359 len += optlen;
360
361 if (skb_gro_header_hard(skb, len)) {
362 guehdr = skb_gro_header_slow(skb, len, off);
363 if (unlikely(!guehdr))
364 goto out;
365 }
366
367 if (unlikely(guehdr->control) || guehdr->version != 0 ||
368 validate_gue_flags(guehdr, optlen))
369 goto out;
370
371 hdrlen = sizeof(*guehdr) + optlen;
372
373 /* Adjust NAPI_GRO_CB(skb)->csum to account for guehdr,
374 * this is needed if there is a remote checkcsum offload.
375 */
376 skb_gro_postpull_rcsum(skb, guehdr, hdrlen);
377
378 data = &guehdr[1];
379
380 if (guehdr->flags & GUE_FLAG_PRIV) {
381 __be32 flags = *(__be32 *)(data + doffset);
382
383 doffset += GUE_LEN_PRIV;
384
385 if (flags & GUE_PFLAG_REMCSUM) {
386 guehdr = gue_gro_remcsum(skb, off, guehdr,
387 data + doffset, hdrlen, &grc,
388 !!(fou->flags &
389 FOU_F_REMCSUM_NOPARTIAL));
390
391 if (!guehdr)
392 goto out;
393
394 data = &guehdr[1];
395
396 doffset += GUE_PLEN_REMCSUM;
397 }
398 }
399
400 skb_gro_pull(skb, hdrlen);
401
402 list_for_each_entry(p, head, list) {
403 const struct guehdr *guehdr2;
404
405 if (!NAPI_GRO_CB(p)->same_flow)
406 continue;
407
408 guehdr2 = (struct guehdr *)(p->data + off);
409
410 /* Compare base GUE header to be equal (covers
411 * hlen, version, proto_ctype, and flags.
412 */
413 if (guehdr->word != guehdr2->word) {
414 NAPI_GRO_CB(p)->same_flow = 0;
415 continue;
416 }
417
418 /* Compare optional fields are the same. */
419 if (guehdr->hlen && memcmp(&guehdr[1], &guehdr2[1],
420 guehdr->hlen << 2)) {
421 NAPI_GRO_CB(p)->same_flow = 0;
422 continue;
423 }
424 }
425
426 proto = guehdr->proto_ctype;
427
428 next_proto:
429
430 /* We can clear the encap_mark for GUE as we are essentially doing
431 * one of two possible things. We are either adding an L4 tunnel
432 * header to the outer L3 tunnel header, or we are simply
433 * treating the GRE tunnel header as though it is a UDP protocol
434 * specific header such as VXLAN or GENEVE.
435 */
436 NAPI_GRO_CB(skb)->encap_mark = 0;
437
438 /* Flag this frame as already having an outer encap header */
439 NAPI_GRO_CB(skb)->is_fou = 1;
440
441 rcu_read_lock();
442 offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
443 ops = rcu_dereference(offloads[proto]);
444 if (WARN_ON_ONCE(!ops || !ops->callbacks.gro_receive))
445 goto out_unlock;
446
447 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
448 flush = 0;
449
450 out_unlock:
451 rcu_read_unlock();
452 out:
453 skb_gro_flush_final_remcsum(skb, pp, flush, &grc);
454
455 return pp;
456 }
457
gue_gro_complete(struct sock * sk,struct sk_buff * skb,int nhoff)458 static int gue_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
459 {
460 struct guehdr *guehdr = (struct guehdr *)(skb->data + nhoff);
461 const struct net_offload __rcu **offloads;
462 const struct net_offload *ops;
463 unsigned int guehlen = 0;
464 u8 proto;
465 int err = -ENOENT;
466
467 switch (guehdr->version) {
468 case 0:
469 proto = guehdr->proto_ctype;
470 guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
471 break;
472 case 1:
473 switch (((struct iphdr *)guehdr)->version) {
474 case 4:
475 proto = IPPROTO_IPIP;
476 break;
477 case 6:
478 proto = IPPROTO_IPV6;
479 break;
480 default:
481 return err;
482 }
483 break;
484 default:
485 return err;
486 }
487
488 rcu_read_lock();
489 offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
490 ops = rcu_dereference(offloads[proto]);
491 if (WARN_ON(!ops || !ops->callbacks.gro_complete))
492 goto out_unlock;
493
494 err = ops->callbacks.gro_complete(skb, nhoff + guehlen);
495
496 skb_set_inner_mac_header(skb, nhoff + guehlen);
497
498 out_unlock:
499 rcu_read_unlock();
500 return err;
501 }
502
fou_cfg_cmp(struct fou * fou,struct fou_cfg * cfg)503 static bool fou_cfg_cmp(struct fou *fou, struct fou_cfg *cfg)
504 {
505 struct sock *sk = fou->sock->sk;
506 struct udp_port_cfg *udp_cfg = &cfg->udp_config;
507
508 if (fou->family != udp_cfg->family ||
509 fou->port != udp_cfg->local_udp_port ||
510 sk->sk_dport != udp_cfg->peer_udp_port ||
511 sk->sk_bound_dev_if != udp_cfg->bind_ifindex)
512 return false;
513
514 if (fou->family == AF_INET) {
515 if (sk->sk_rcv_saddr != udp_cfg->local_ip.s_addr ||
516 sk->sk_daddr != udp_cfg->peer_ip.s_addr)
517 return false;
518 else
519 return true;
520 #if IS_ENABLED(CONFIG_IPV6)
521 } else {
522 if (ipv6_addr_cmp(&sk->sk_v6_rcv_saddr, &udp_cfg->local_ip6) ||
523 ipv6_addr_cmp(&sk->sk_v6_daddr, &udp_cfg->peer_ip6))
524 return false;
525 else
526 return true;
527 #endif
528 }
529
530 return false;
531 }
532
fou_add_to_port_list(struct net * net,struct fou * fou,struct fou_cfg * cfg)533 static int fou_add_to_port_list(struct net *net, struct fou *fou,
534 struct fou_cfg *cfg)
535 {
536 struct fou_net *fn = net_generic(net, fou_net_id);
537 struct fou *fout;
538
539 mutex_lock(&fn->fou_lock);
540 list_for_each_entry(fout, &fn->fou_list, list) {
541 if (fou_cfg_cmp(fout, cfg)) {
542 mutex_unlock(&fn->fou_lock);
543 return -EALREADY;
544 }
545 }
546
547 list_add(&fou->list, &fn->fou_list);
548 mutex_unlock(&fn->fou_lock);
549
550 return 0;
551 }
552
fou_release(struct fou * fou)553 static void fou_release(struct fou *fou)
554 {
555 struct socket *sock = fou->sock;
556
557 list_del(&fou->list);
558 udp_tunnel_sock_release(sock);
559
560 kfree_rcu(fou, rcu);
561 }
562
fou_create(struct net * net,struct fou_cfg * cfg,struct socket ** sockp)563 static int fou_create(struct net *net, struct fou_cfg *cfg,
564 struct socket **sockp)
565 {
566 struct socket *sock = NULL;
567 struct fou *fou = NULL;
568 struct sock *sk;
569 struct udp_tunnel_sock_cfg tunnel_cfg;
570 int err;
571
572 /* Open UDP socket */
573 err = udp_sock_create(net, &cfg->udp_config, &sock);
574 if (err < 0)
575 goto error;
576
577 /* Allocate FOU port structure */
578 fou = kzalloc(sizeof(*fou), GFP_KERNEL);
579 if (!fou) {
580 err = -ENOMEM;
581 goto error;
582 }
583
584 sk = sock->sk;
585
586 fou->port = cfg->udp_config.local_udp_port;
587 fou->family = cfg->udp_config.family;
588 fou->flags = cfg->flags;
589 fou->type = cfg->type;
590 fou->sock = sock;
591
592 memset(&tunnel_cfg, 0, sizeof(tunnel_cfg));
593 tunnel_cfg.encap_type = 1;
594 tunnel_cfg.sk_user_data = fou;
595 tunnel_cfg.encap_destroy = NULL;
596
597 /* Initial for fou type */
598 switch (cfg->type) {
599 case FOU_ENCAP_DIRECT:
600 tunnel_cfg.encap_rcv = fou_udp_recv;
601 tunnel_cfg.gro_receive = fou_gro_receive;
602 tunnel_cfg.gro_complete = fou_gro_complete;
603 fou->protocol = cfg->protocol;
604 break;
605 case FOU_ENCAP_GUE:
606 tunnel_cfg.encap_rcv = gue_udp_recv;
607 tunnel_cfg.gro_receive = gue_gro_receive;
608 tunnel_cfg.gro_complete = gue_gro_complete;
609 break;
610 default:
611 err = -EINVAL;
612 goto error;
613 }
614
615 setup_udp_tunnel_sock(net, sock, &tunnel_cfg);
616
617 sk->sk_allocation = GFP_ATOMIC;
618
619 err = fou_add_to_port_list(net, fou, cfg);
620 if (err)
621 goto error;
622
623 if (sockp)
624 *sockp = sock;
625
626 return 0;
627
628 error:
629 kfree(fou);
630 if (sock)
631 udp_tunnel_sock_release(sock);
632
633 return err;
634 }
635
fou_destroy(struct net * net,struct fou_cfg * cfg)636 static int fou_destroy(struct net *net, struct fou_cfg *cfg)
637 {
638 struct fou_net *fn = net_generic(net, fou_net_id);
639 int err = -EINVAL;
640 struct fou *fou;
641
642 mutex_lock(&fn->fou_lock);
643 list_for_each_entry(fou, &fn->fou_list, list) {
644 if (fou_cfg_cmp(fou, cfg)) {
645 fou_release(fou);
646 err = 0;
647 break;
648 }
649 }
650 mutex_unlock(&fn->fou_lock);
651
652 return err;
653 }
654
655 static struct genl_family fou_nl_family;
656
657 static const struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
658 [FOU_ATTR_PORT] = { .type = NLA_U16, },
659 [FOU_ATTR_AF] = { .type = NLA_U8, },
660 [FOU_ATTR_IPPROTO] = { .type = NLA_U8, },
661 [FOU_ATTR_TYPE] = { .type = NLA_U8, },
662 [FOU_ATTR_REMCSUM_NOPARTIAL] = { .type = NLA_FLAG, },
663 [FOU_ATTR_LOCAL_V4] = { .type = NLA_U32, },
664 [FOU_ATTR_PEER_V4] = { .type = NLA_U32, },
665 [FOU_ATTR_LOCAL_V6] = { .len = sizeof(struct in6_addr), },
666 [FOU_ATTR_PEER_V6] = { .len = sizeof(struct in6_addr), },
667 [FOU_ATTR_PEER_PORT] = { .type = NLA_U16, },
668 [FOU_ATTR_IFINDEX] = { .type = NLA_S32, },
669 };
670
parse_nl_config(struct genl_info * info,struct fou_cfg * cfg)671 static int parse_nl_config(struct genl_info *info,
672 struct fou_cfg *cfg)
673 {
674 bool has_local = false, has_peer = false;
675 struct nlattr *attr;
676 int ifindex;
677 __be16 port;
678
679 memset(cfg, 0, sizeof(*cfg));
680
681 cfg->udp_config.family = AF_INET;
682
683 if (info->attrs[FOU_ATTR_AF]) {
684 u8 family = nla_get_u8(info->attrs[FOU_ATTR_AF]);
685
686 switch (family) {
687 case AF_INET:
688 break;
689 case AF_INET6:
690 cfg->udp_config.ipv6_v6only = 1;
691 break;
692 default:
693 return -EAFNOSUPPORT;
694 }
695
696 cfg->udp_config.family = family;
697 }
698
699 if (info->attrs[FOU_ATTR_PORT]) {
700 port = nla_get_be16(info->attrs[FOU_ATTR_PORT]);
701 cfg->udp_config.local_udp_port = port;
702 }
703
704 if (info->attrs[FOU_ATTR_IPPROTO])
705 cfg->protocol = nla_get_u8(info->attrs[FOU_ATTR_IPPROTO]);
706
707 if (info->attrs[FOU_ATTR_TYPE])
708 cfg->type = nla_get_u8(info->attrs[FOU_ATTR_TYPE]);
709
710 if (info->attrs[FOU_ATTR_REMCSUM_NOPARTIAL])
711 cfg->flags |= FOU_F_REMCSUM_NOPARTIAL;
712
713 if (cfg->udp_config.family == AF_INET) {
714 if (info->attrs[FOU_ATTR_LOCAL_V4]) {
715 attr = info->attrs[FOU_ATTR_LOCAL_V4];
716 cfg->udp_config.local_ip.s_addr = nla_get_in_addr(attr);
717 has_local = true;
718 }
719
720 if (info->attrs[FOU_ATTR_PEER_V4]) {
721 attr = info->attrs[FOU_ATTR_PEER_V4];
722 cfg->udp_config.peer_ip.s_addr = nla_get_in_addr(attr);
723 has_peer = true;
724 }
725 #if IS_ENABLED(CONFIG_IPV6)
726 } else {
727 if (info->attrs[FOU_ATTR_LOCAL_V6]) {
728 attr = info->attrs[FOU_ATTR_LOCAL_V6];
729 cfg->udp_config.local_ip6 = nla_get_in6_addr(attr);
730 has_local = true;
731 }
732
733 if (info->attrs[FOU_ATTR_PEER_V6]) {
734 attr = info->attrs[FOU_ATTR_PEER_V6];
735 cfg->udp_config.peer_ip6 = nla_get_in6_addr(attr);
736 has_peer = true;
737 }
738 #endif
739 }
740
741 if (has_peer) {
742 if (info->attrs[FOU_ATTR_PEER_PORT]) {
743 port = nla_get_be16(info->attrs[FOU_ATTR_PEER_PORT]);
744 cfg->udp_config.peer_udp_port = port;
745 } else {
746 return -EINVAL;
747 }
748 }
749
750 if (info->attrs[FOU_ATTR_IFINDEX]) {
751 if (!has_local)
752 return -EINVAL;
753
754 ifindex = nla_get_s32(info->attrs[FOU_ATTR_IFINDEX]);
755
756 cfg->udp_config.bind_ifindex = ifindex;
757 }
758
759 return 0;
760 }
761
fou_nl_cmd_add_port(struct sk_buff * skb,struct genl_info * info)762 static int fou_nl_cmd_add_port(struct sk_buff *skb, struct genl_info *info)
763 {
764 struct net *net = genl_info_net(info);
765 struct fou_cfg cfg;
766 int err;
767
768 err = parse_nl_config(info, &cfg);
769 if (err)
770 return err;
771
772 return fou_create(net, &cfg, NULL);
773 }
774
fou_nl_cmd_rm_port(struct sk_buff * skb,struct genl_info * info)775 static int fou_nl_cmd_rm_port(struct sk_buff *skb, struct genl_info *info)
776 {
777 struct net *net = genl_info_net(info);
778 struct fou_cfg cfg;
779 int err;
780
781 err = parse_nl_config(info, &cfg);
782 if (err)
783 return err;
784
785 return fou_destroy(net, &cfg);
786 }
787
fou_fill_info(struct fou * fou,struct sk_buff * msg)788 static int fou_fill_info(struct fou *fou, struct sk_buff *msg)
789 {
790 struct sock *sk = fou->sock->sk;
791
792 if (nla_put_u8(msg, FOU_ATTR_AF, fou->sock->sk->sk_family) ||
793 nla_put_be16(msg, FOU_ATTR_PORT, fou->port) ||
794 nla_put_be16(msg, FOU_ATTR_PEER_PORT, sk->sk_dport) ||
795 nla_put_u8(msg, FOU_ATTR_IPPROTO, fou->protocol) ||
796 nla_put_u8(msg, FOU_ATTR_TYPE, fou->type) ||
797 nla_put_s32(msg, FOU_ATTR_IFINDEX, sk->sk_bound_dev_if))
798 return -1;
799
800 if (fou->flags & FOU_F_REMCSUM_NOPARTIAL)
801 if (nla_put_flag(msg, FOU_ATTR_REMCSUM_NOPARTIAL))
802 return -1;
803
804 if (fou->sock->sk->sk_family == AF_INET) {
805 if (nla_put_in_addr(msg, FOU_ATTR_LOCAL_V4, sk->sk_rcv_saddr))
806 return -1;
807
808 if (nla_put_in_addr(msg, FOU_ATTR_PEER_V4, sk->sk_daddr))
809 return -1;
810 #if IS_ENABLED(CONFIG_IPV6)
811 } else {
812 if (nla_put_in6_addr(msg, FOU_ATTR_LOCAL_V6,
813 &sk->sk_v6_rcv_saddr))
814 return -1;
815
816 if (nla_put_in6_addr(msg, FOU_ATTR_PEER_V6, &sk->sk_v6_daddr))
817 return -1;
818 #endif
819 }
820
821 return 0;
822 }
823
fou_dump_info(struct fou * fou,u32 portid,u32 seq,u32 flags,struct sk_buff * skb,u8 cmd)824 static int fou_dump_info(struct fou *fou, u32 portid, u32 seq,
825 u32 flags, struct sk_buff *skb, u8 cmd)
826 {
827 void *hdr;
828
829 hdr = genlmsg_put(skb, portid, seq, &fou_nl_family, flags, cmd);
830 if (!hdr)
831 return -ENOMEM;
832
833 if (fou_fill_info(fou, skb) < 0)
834 goto nla_put_failure;
835
836 genlmsg_end(skb, hdr);
837 return 0;
838
839 nla_put_failure:
840 genlmsg_cancel(skb, hdr);
841 return -EMSGSIZE;
842 }
843
fou_nl_cmd_get_port(struct sk_buff * skb,struct genl_info * info)844 static int fou_nl_cmd_get_port(struct sk_buff *skb, struct genl_info *info)
845 {
846 struct net *net = genl_info_net(info);
847 struct fou_net *fn = net_generic(net, fou_net_id);
848 struct sk_buff *msg;
849 struct fou_cfg cfg;
850 struct fou *fout;
851 __be16 port;
852 u8 family;
853 int ret;
854
855 ret = parse_nl_config(info, &cfg);
856 if (ret)
857 return ret;
858 port = cfg.udp_config.local_udp_port;
859 if (port == 0)
860 return -EINVAL;
861
862 family = cfg.udp_config.family;
863 if (family != AF_INET && family != AF_INET6)
864 return -EINVAL;
865
866 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
867 if (!msg)
868 return -ENOMEM;
869
870 ret = -ESRCH;
871 mutex_lock(&fn->fou_lock);
872 list_for_each_entry(fout, &fn->fou_list, list) {
873 if (fou_cfg_cmp(fout, &cfg)) {
874 ret = fou_dump_info(fout, info->snd_portid,
875 info->snd_seq, 0, msg,
876 info->genlhdr->cmd);
877 break;
878 }
879 }
880 mutex_unlock(&fn->fou_lock);
881 if (ret < 0)
882 goto out_free;
883
884 return genlmsg_reply(msg, info);
885
886 out_free:
887 nlmsg_free(msg);
888 return ret;
889 }
890
fou_nl_dump(struct sk_buff * skb,struct netlink_callback * cb)891 static int fou_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
892 {
893 struct net *net = sock_net(skb->sk);
894 struct fou_net *fn = net_generic(net, fou_net_id);
895 struct fou *fout;
896 int idx = 0, ret;
897
898 mutex_lock(&fn->fou_lock);
899 list_for_each_entry(fout, &fn->fou_list, list) {
900 if (idx++ < cb->args[0])
901 continue;
902 ret = fou_dump_info(fout, NETLINK_CB(cb->skb).portid,
903 cb->nlh->nlmsg_seq, NLM_F_MULTI,
904 skb, FOU_CMD_GET);
905 if (ret)
906 break;
907 }
908 mutex_unlock(&fn->fou_lock);
909
910 cb->args[0] = idx;
911 return skb->len;
912 }
913
914 static const struct genl_small_ops fou_nl_ops[] = {
915 {
916 .cmd = FOU_CMD_ADD,
917 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
918 .doit = fou_nl_cmd_add_port,
919 .flags = GENL_ADMIN_PERM,
920 },
921 {
922 .cmd = FOU_CMD_DEL,
923 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
924 .doit = fou_nl_cmd_rm_port,
925 .flags = GENL_ADMIN_PERM,
926 },
927 {
928 .cmd = FOU_CMD_GET,
929 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
930 .doit = fou_nl_cmd_get_port,
931 .dumpit = fou_nl_dump,
932 },
933 };
934
935 static struct genl_family fou_nl_family __ro_after_init = {
936 .hdrsize = 0,
937 .name = FOU_GENL_NAME,
938 .version = FOU_GENL_VERSION,
939 .maxattr = FOU_ATTR_MAX,
940 .policy = fou_nl_policy,
941 .netnsok = true,
942 .module = THIS_MODULE,
943 .small_ops = fou_nl_ops,
944 .n_small_ops = ARRAY_SIZE(fou_nl_ops),
945 };
946
fou_encap_hlen(struct ip_tunnel_encap * e)947 size_t fou_encap_hlen(struct ip_tunnel_encap *e)
948 {
949 return sizeof(struct udphdr);
950 }
951 EXPORT_SYMBOL(fou_encap_hlen);
952
gue_encap_hlen(struct ip_tunnel_encap * e)953 size_t gue_encap_hlen(struct ip_tunnel_encap *e)
954 {
955 size_t len;
956 bool need_priv = false;
957
958 len = sizeof(struct udphdr) + sizeof(struct guehdr);
959
960 if (e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) {
961 len += GUE_PLEN_REMCSUM;
962 need_priv = true;
963 }
964
965 len += need_priv ? GUE_LEN_PRIV : 0;
966
967 return len;
968 }
969 EXPORT_SYMBOL(gue_encap_hlen);
970
__fou_build_header(struct sk_buff * skb,struct ip_tunnel_encap * e,u8 * protocol,__be16 * sport,int type)971 int __fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
972 u8 *protocol, __be16 *sport, int type)
973 {
974 int err;
975
976 err = iptunnel_handle_offloads(skb, type);
977 if (err)
978 return err;
979
980 *sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
981 skb, 0, 0, false);
982
983 return 0;
984 }
985 EXPORT_SYMBOL(__fou_build_header);
986
__gue_build_header(struct sk_buff * skb,struct ip_tunnel_encap * e,u8 * protocol,__be16 * sport,int type)987 int __gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
988 u8 *protocol, __be16 *sport, int type)
989 {
990 struct guehdr *guehdr;
991 size_t hdrlen, optlen = 0;
992 void *data;
993 bool need_priv = false;
994 int err;
995
996 if ((e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) &&
997 skb->ip_summed == CHECKSUM_PARTIAL) {
998 optlen += GUE_PLEN_REMCSUM;
999 type |= SKB_GSO_TUNNEL_REMCSUM;
1000 need_priv = true;
1001 }
1002
1003 optlen += need_priv ? GUE_LEN_PRIV : 0;
1004
1005 err = iptunnel_handle_offloads(skb, type);
1006 if (err)
1007 return err;
1008
1009 /* Get source port (based on flow hash) before skb_push */
1010 *sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
1011 skb, 0, 0, false);
1012
1013 hdrlen = sizeof(struct guehdr) + optlen;
1014
1015 skb_push(skb, hdrlen);
1016
1017 guehdr = (struct guehdr *)skb->data;
1018
1019 guehdr->control = 0;
1020 guehdr->version = 0;
1021 guehdr->hlen = optlen >> 2;
1022 guehdr->flags = 0;
1023 guehdr->proto_ctype = *protocol;
1024
1025 data = &guehdr[1];
1026
1027 if (need_priv) {
1028 __be32 *flags = data;
1029
1030 guehdr->flags |= GUE_FLAG_PRIV;
1031 *flags = 0;
1032 data += GUE_LEN_PRIV;
1033
1034 if (type & SKB_GSO_TUNNEL_REMCSUM) {
1035 u16 csum_start = skb_checksum_start_offset(skb);
1036 __be16 *pd = data;
1037
1038 if (csum_start < hdrlen)
1039 return -EINVAL;
1040
1041 csum_start -= hdrlen;
1042 pd[0] = htons(csum_start);
1043 pd[1] = htons(csum_start + skb->csum_offset);
1044
1045 if (!skb_is_gso(skb)) {
1046 skb->ip_summed = CHECKSUM_NONE;
1047 skb->encapsulation = 0;
1048 }
1049
1050 *flags |= GUE_PFLAG_REMCSUM;
1051 data += GUE_PLEN_REMCSUM;
1052 }
1053
1054 }
1055
1056 return 0;
1057 }
1058 EXPORT_SYMBOL(__gue_build_header);
1059
1060 #ifdef CONFIG_NET_FOU_IP_TUNNELS
1061
fou_build_udp(struct sk_buff * skb,struct ip_tunnel_encap * e,struct flowi4 * fl4,u8 * protocol,__be16 sport)1062 static void fou_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
1063 struct flowi4 *fl4, u8 *protocol, __be16 sport)
1064 {
1065 struct udphdr *uh;
1066
1067 skb_push(skb, sizeof(struct udphdr));
1068 skb_reset_transport_header(skb);
1069
1070 uh = udp_hdr(skb);
1071
1072 uh->dest = e->dport;
1073 uh->source = sport;
1074 uh->len = htons(skb->len);
1075 udp_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM), skb,
1076 fl4->saddr, fl4->daddr, skb->len);
1077
1078 *protocol = IPPROTO_UDP;
1079 }
1080
fou_build_header(struct sk_buff * skb,struct ip_tunnel_encap * e,u8 * protocol,struct flowi4 * fl4)1081 static int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
1082 u8 *protocol, struct flowi4 *fl4)
1083 {
1084 int type = e->flags & TUNNEL_ENCAP_FLAG_CSUM ? SKB_GSO_UDP_TUNNEL_CSUM :
1085 SKB_GSO_UDP_TUNNEL;
1086 __be16 sport;
1087 int err;
1088
1089 err = __fou_build_header(skb, e, protocol, &sport, type);
1090 if (err)
1091 return err;
1092
1093 fou_build_udp(skb, e, fl4, protocol, sport);
1094
1095 return 0;
1096 }
1097
gue_build_header(struct sk_buff * skb,struct ip_tunnel_encap * e,u8 * protocol,struct flowi4 * fl4)1098 static int gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
1099 u8 *protocol, struct flowi4 *fl4)
1100 {
1101 int type = e->flags & TUNNEL_ENCAP_FLAG_CSUM ? SKB_GSO_UDP_TUNNEL_CSUM :
1102 SKB_GSO_UDP_TUNNEL;
1103 __be16 sport;
1104 int err;
1105
1106 err = __gue_build_header(skb, e, protocol, &sport, type);
1107 if (err)
1108 return err;
1109
1110 fou_build_udp(skb, e, fl4, protocol, sport);
1111
1112 return 0;
1113 }
1114
gue_err_proto_handler(int proto,struct sk_buff * skb,u32 info)1115 static int gue_err_proto_handler(int proto, struct sk_buff *skb, u32 info)
1116 {
1117 const struct net_protocol *ipprot = rcu_dereference(inet_protos[proto]);
1118
1119 if (ipprot && ipprot->err_handler) {
1120 if (!ipprot->err_handler(skb, info))
1121 return 0;
1122 }
1123
1124 return -ENOENT;
1125 }
1126
gue_err(struct sk_buff * skb,u32 info)1127 static int gue_err(struct sk_buff *skb, u32 info)
1128 {
1129 int transport_offset = skb_transport_offset(skb);
1130 struct guehdr *guehdr;
1131 size_t len, optlen;
1132 int ret;
1133
1134 len = sizeof(struct udphdr) + sizeof(struct guehdr);
1135 if (!pskb_may_pull(skb, transport_offset + len))
1136 return -EINVAL;
1137
1138 guehdr = (struct guehdr *)&udp_hdr(skb)[1];
1139
1140 switch (guehdr->version) {
1141 case 0: /* Full GUE header present */
1142 break;
1143 case 1: {
1144 /* Direct encapsulation of IPv4 or IPv6 */
1145 skb_set_transport_header(skb, -(int)sizeof(struct icmphdr));
1146
1147 switch (((struct iphdr *)guehdr)->version) {
1148 case 4:
1149 ret = gue_err_proto_handler(IPPROTO_IPIP, skb, info);
1150 goto out;
1151 #if IS_ENABLED(CONFIG_IPV6)
1152 case 6:
1153 ret = gue_err_proto_handler(IPPROTO_IPV6, skb, info);
1154 goto out;
1155 #endif
1156 default:
1157 ret = -EOPNOTSUPP;
1158 goto out;
1159 }
1160 }
1161 default: /* Undefined version */
1162 return -EOPNOTSUPP;
1163 }
1164
1165 if (guehdr->control)
1166 return -ENOENT;
1167
1168 optlen = guehdr->hlen << 2;
1169
1170 if (!pskb_may_pull(skb, transport_offset + len + optlen))
1171 return -EINVAL;
1172
1173 guehdr = (struct guehdr *)&udp_hdr(skb)[1];
1174 if (validate_gue_flags(guehdr, optlen))
1175 return -EINVAL;
1176
1177 /* Handling exceptions for direct UDP encapsulation in GUE would lead to
1178 * recursion. Besides, this kind of encapsulation can't even be
1179 * configured currently. Discard this.
1180 */
1181 if (guehdr->proto_ctype == IPPROTO_UDP ||
1182 guehdr->proto_ctype == IPPROTO_UDPLITE)
1183 return -EOPNOTSUPP;
1184
1185 skb_set_transport_header(skb, -(int)sizeof(struct icmphdr));
1186 ret = gue_err_proto_handler(guehdr->proto_ctype, skb, info);
1187
1188 out:
1189 skb_set_transport_header(skb, transport_offset);
1190 return ret;
1191 }
1192
1193
1194 static const struct ip_tunnel_encap_ops fou_iptun_ops = {
1195 .encap_hlen = fou_encap_hlen,
1196 .build_header = fou_build_header,
1197 .err_handler = gue_err,
1198 };
1199
1200 static const struct ip_tunnel_encap_ops gue_iptun_ops = {
1201 .encap_hlen = gue_encap_hlen,
1202 .build_header = gue_build_header,
1203 .err_handler = gue_err,
1204 };
1205
ip_tunnel_encap_add_fou_ops(void)1206 static int ip_tunnel_encap_add_fou_ops(void)
1207 {
1208 int ret;
1209
1210 ret = ip_tunnel_encap_add_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
1211 if (ret < 0) {
1212 pr_err("can't add fou ops\n");
1213 return ret;
1214 }
1215
1216 ret = ip_tunnel_encap_add_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
1217 if (ret < 0) {
1218 pr_err("can't add gue ops\n");
1219 ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
1220 return ret;
1221 }
1222
1223 return 0;
1224 }
1225
ip_tunnel_encap_del_fou_ops(void)1226 static void ip_tunnel_encap_del_fou_ops(void)
1227 {
1228 ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
1229 ip_tunnel_encap_del_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
1230 }
1231
1232 #else
1233
ip_tunnel_encap_add_fou_ops(void)1234 static int ip_tunnel_encap_add_fou_ops(void)
1235 {
1236 return 0;
1237 }
1238
ip_tunnel_encap_del_fou_ops(void)1239 static void ip_tunnel_encap_del_fou_ops(void)
1240 {
1241 }
1242
1243 #endif
1244
fou_init_net(struct net * net)1245 static __net_init int fou_init_net(struct net *net)
1246 {
1247 struct fou_net *fn = net_generic(net, fou_net_id);
1248
1249 INIT_LIST_HEAD(&fn->fou_list);
1250 mutex_init(&fn->fou_lock);
1251 return 0;
1252 }
1253
fou_exit_net(struct net * net)1254 static __net_exit void fou_exit_net(struct net *net)
1255 {
1256 struct fou_net *fn = net_generic(net, fou_net_id);
1257 struct fou *fou, *next;
1258
1259 /* Close all the FOU sockets */
1260 mutex_lock(&fn->fou_lock);
1261 list_for_each_entry_safe(fou, next, &fn->fou_list, list)
1262 fou_release(fou);
1263 mutex_unlock(&fn->fou_lock);
1264 }
1265
1266 static struct pernet_operations fou_net_ops = {
1267 .init = fou_init_net,
1268 .exit = fou_exit_net,
1269 .id = &fou_net_id,
1270 .size = sizeof(struct fou_net),
1271 };
1272
fou_init(void)1273 static int __init fou_init(void)
1274 {
1275 int ret;
1276
1277 ret = register_pernet_device(&fou_net_ops);
1278 if (ret)
1279 goto exit;
1280
1281 ret = genl_register_family(&fou_nl_family);
1282 if (ret < 0)
1283 goto unregister;
1284
1285 ret = ip_tunnel_encap_add_fou_ops();
1286 if (ret == 0)
1287 return 0;
1288
1289 genl_unregister_family(&fou_nl_family);
1290 unregister:
1291 unregister_pernet_device(&fou_net_ops);
1292 exit:
1293 return ret;
1294 }
1295
fou_fini(void)1296 static void __exit fou_fini(void)
1297 {
1298 ip_tunnel_encap_del_fou_ops();
1299 genl_unregister_family(&fou_nl_family);
1300 unregister_pernet_device(&fou_net_ops);
1301 }
1302
1303 module_init(fou_init);
1304 module_exit(fou_fini);
1305 MODULE_AUTHOR("Tom Herbert <therbert@google.com>");
1306 MODULE_LICENSE("GPL");
1307 MODULE_DESCRIPTION("Foo over UDP");
1308