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