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