1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * IPV4 GSO/GRO offload support
4 * Linux INET implementation
5 *
6 * UDPv4 GSO support
7 */
8
9 #include <linux/skbuff.h>
10 #include <net/gro.h>
11 #include <net/gso.h>
12 #include <net/udp.h>
13 #include <net/protocol.h>
14 #include <net/inet_common.h>
15
16 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
17 netdev_features_t features,
18 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
19 netdev_features_t features),
20 __be16 new_protocol, bool is_ipv6)
21 {
22 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
23 bool remcsum, need_csum, offload_csum, gso_partial;
24 struct sk_buff *segs = ERR_PTR(-EINVAL);
25 struct udphdr *uh = udp_hdr(skb);
26 u16 mac_offset = skb->mac_header;
27 __be16 protocol = skb->protocol;
28 u16 mac_len = skb->mac_len;
29 int udp_offset, outer_hlen;
30 __wsum partial;
31 bool need_ipsec;
32
33 if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
34 goto out;
35
36 /* Adjust partial header checksum to negate old length.
37 * We cannot rely on the value contained in uh->len as it is
38 * possible that the actual value exceeds the boundaries of the
39 * 16 bit length field due to the header being added outside of an
40 * IP or IPv6 frame that was already limited to 64K - 1.
41 */
42 if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
43 partial = (__force __wsum)uh->len;
44 else
45 partial = (__force __wsum)htonl(skb->len);
46 partial = csum_sub(csum_unfold(uh->check), partial);
47
48 /* setup inner skb. */
49 skb->encapsulation = 0;
50 SKB_GSO_CB(skb)->encap_level = 0;
51 __skb_pull(skb, tnl_hlen);
52 skb_reset_mac_header(skb);
53 skb_set_network_header(skb, skb_inner_network_offset(skb));
54 skb_set_transport_header(skb, skb_inner_transport_offset(skb));
55 skb->mac_len = skb_inner_network_offset(skb);
56 skb->protocol = new_protocol;
57
58 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
59 skb->encap_hdr_csum = need_csum;
60
61 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
62 skb->remcsum_offload = remcsum;
63
64 need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
65 /* Try to offload checksum if possible */
66 offload_csum = !!(need_csum &&
67 !need_ipsec &&
68 (skb->dev->features &
69 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
70 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
71
72 features &= skb->dev->hw_enc_features;
73 if (need_csum)
74 features &= ~NETIF_F_SCTP_CRC;
75
76 /* The only checksum offload we care about from here on out is the
77 * outer one so strip the existing checksum feature flags and
78 * instead set the flag based on our outer checksum offload value.
79 */
80 if (remcsum) {
81 features &= ~NETIF_F_CSUM_MASK;
82 if (!need_csum || offload_csum)
83 features |= NETIF_F_HW_CSUM;
84 }
85
86 /* segment inner packet. */
87 segs = gso_inner_segment(skb, features);
88 if (IS_ERR_OR_NULL(segs)) {
89 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
90 mac_len);
91 goto out;
92 }
93
94 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
95
96 outer_hlen = skb_tnl_header_len(skb);
97 udp_offset = outer_hlen - tnl_hlen;
98 skb = segs;
99 do {
100 unsigned int len;
101
102 if (remcsum)
103 skb->ip_summed = CHECKSUM_NONE;
104
105 /* Set up inner headers if we are offloading inner checksum */
106 if (skb->ip_summed == CHECKSUM_PARTIAL) {
107 skb_reset_inner_headers(skb);
108 skb->encapsulation = 1;
109 }
110
111 skb->mac_len = mac_len;
112 skb->protocol = protocol;
113
114 __skb_push(skb, outer_hlen);
115 skb_reset_mac_header(skb);
116 skb_set_network_header(skb, mac_len);
117 skb_set_transport_header(skb, udp_offset);
118 len = skb->len - udp_offset;
119 uh = udp_hdr(skb);
120
121 /* If we are only performing partial GSO the inner header
122 * will be using a length value equal to only one MSS sized
123 * segment instead of the entire frame.
124 */
125 if (gso_partial && skb_is_gso(skb)) {
126 uh->len = htons(skb_shinfo(skb)->gso_size +
127 SKB_GSO_CB(skb)->data_offset +
128 skb->head - (unsigned char *)uh);
129 } else {
130 uh->len = htons(len);
131 }
132
133 if (!need_csum)
134 continue;
135
136 uh->check = ~csum_fold(csum_add(partial,
137 (__force __wsum)htonl(len)));
138
139 if (skb->encapsulation || !offload_csum) {
140 uh->check = gso_make_checksum(skb, ~uh->check);
141 if (uh->check == 0)
142 uh->check = CSUM_MANGLED_0;
143 } else {
144 skb->ip_summed = CHECKSUM_PARTIAL;
145 skb->csum_start = skb_transport_header(skb) - skb->head;
146 skb->csum_offset = offsetof(struct udphdr, check);
147 }
148 } while ((skb = skb->next));
149 out:
150 return segs;
151 }
152
153 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
154 netdev_features_t features,
155 bool is_ipv6)
156 {
157 const struct net_offload __rcu **offloads;
158 __be16 protocol = skb->protocol;
159 const struct net_offload *ops;
160 struct sk_buff *segs = ERR_PTR(-EINVAL);
161 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
162 netdev_features_t features);
163
164 rcu_read_lock();
165
166 switch (skb->inner_protocol_type) {
167 case ENCAP_TYPE_ETHER:
168 protocol = skb->inner_protocol;
169 gso_inner_segment = skb_mac_gso_segment;
170 break;
171 case ENCAP_TYPE_IPPROTO:
172 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
173 ops = rcu_dereference(offloads[skb->inner_ipproto]);
174 if (!ops || !ops->callbacks.gso_segment)
175 goto out_unlock;
176 gso_inner_segment = ops->callbacks.gso_segment;
177 break;
178 default:
179 goto out_unlock;
180 }
181
182 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
183 protocol, is_ipv6);
184
185 out_unlock:
186 rcu_read_unlock();
187
188 return segs;
189 }
190 EXPORT_SYMBOL(skb_udp_tunnel_segment);
191
192 static void __udpv4_gso_segment_csum(struct sk_buff *seg,
193 __be32 *oldip, __be32 *newip,
194 __be16 *oldport, __be16 *newport)
195 {
196 struct udphdr *uh;
197 struct iphdr *iph;
198
199 if (*oldip == *newip && *oldport == *newport)
200 return;
201
202 uh = udp_hdr(seg);
203 iph = ip_hdr(seg);
204
205 if (uh->check) {
206 inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
207 true);
208 inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
209 false);
210 if (!uh->check)
211 uh->check = CSUM_MANGLED_0;
212 }
213 *oldport = *newport;
214
215 csum_replace4(&iph->check, *oldip, *newip);
216 *oldip = *newip;
217 }
218
219 static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
220 {
221 struct sk_buff *seg;
222 struct udphdr *uh, *uh2;
223 struct iphdr *iph, *iph2;
224
225 seg = segs;
226 uh = udp_hdr(seg);
227 iph = ip_hdr(seg);
228
229 if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
230 (udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
231 (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
232 (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
233 return segs;
234
235 while ((seg = seg->next)) {
236 uh2 = udp_hdr(seg);
237 iph2 = ip_hdr(seg);
238
239 __udpv4_gso_segment_csum(seg,
240 &iph2->saddr, &iph->saddr,
241 &uh2->source, &uh->source);
242 __udpv4_gso_segment_csum(seg,
243 &iph2->daddr, &iph->daddr,
244 &uh2->dest, &uh->dest);
245 }
246
247 return segs;
248 }
249
250 static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
251 netdev_features_t features,
252 bool is_ipv6)
253 {
254 unsigned int mss = skb_shinfo(skb)->gso_size;
255
256 skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
257 if (IS_ERR(skb))
258 return skb;
259
260 udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
261
262 return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);
263 }
264
265 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
266 netdev_features_t features, bool is_ipv6)
267 {
268 struct sock *sk = gso_skb->sk;
269 unsigned int sum_truesize = 0;
270 struct sk_buff *segs, *seg;
271 struct udphdr *uh;
272 unsigned int mss;
273 bool copy_dtor;
274 __sum16 check;
275 __be16 newlen;
276
277 mss = skb_shinfo(gso_skb)->gso_size;
278 if (gso_skb->len <= sizeof(*uh) + mss)
279 return ERR_PTR(-EINVAL);
280
281 if (unlikely(skb_checksum_start(gso_skb) !=
282 skb_transport_header(gso_skb) &&
283 !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)))
284 return ERR_PTR(-EINVAL);
285
286 /* We don't know if egress device can segment and checksum the packet
287 * when IPv6 extension headers are present. Fall back to software GSO.
288 */
289 if (gso_skb->ip_summed != CHECKSUM_PARTIAL)
290 features &= ~(NETIF_F_GSO_UDP_L4 | NETIF_F_CSUM_MASK);
291
292 if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) {
293 /* Packet is from an untrusted source, reset gso_segs. */
294 skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh),
295 mss);
296 return NULL;
297 }
298
299 if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) {
300 /* Detect modified geometry and pass those to skb_segment. */
301 if (skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size)
302 return __udp_gso_segment_list(gso_skb, features, is_ipv6);
303
304 /* Setup csum, as fraglist skips this in udp4_gro_receive. */
305 gso_skb->csum_start = skb_transport_header(gso_skb) - gso_skb->head;
306 gso_skb->csum_offset = offsetof(struct udphdr, check);
307 gso_skb->ip_summed = CHECKSUM_PARTIAL;
308
309 uh = udp_hdr(gso_skb);
310 if (is_ipv6)
311 uh->check = ~udp_v6_check(gso_skb->len,
312 &ipv6_hdr(gso_skb)->saddr,
313 &ipv6_hdr(gso_skb)->daddr, 0);
314 else
315 uh->check = ~udp_v4_check(gso_skb->len,
316 ip_hdr(gso_skb)->saddr,
317 ip_hdr(gso_skb)->daddr, 0);
318 }
319
320 skb_pull(gso_skb, sizeof(*uh));
321
322 /* clear destructor to avoid skb_segment assigning it to tail */
323 copy_dtor = gso_skb->destructor == sock_wfree;
324 if (copy_dtor)
325 gso_skb->destructor = NULL;
326
327 segs = skb_segment(gso_skb, features);
328 if (IS_ERR_OR_NULL(segs)) {
329 if (copy_dtor)
330 gso_skb->destructor = sock_wfree;
331 return segs;
332 }
333
334 /* GSO partial and frag_list segmentation only requires splitting
335 * the frame into an MSS multiple and possibly a remainder, both
336 * cases return a GSO skb. So update the mss now.
337 */
338 if (skb_is_gso(segs))
339 mss *= skb_shinfo(segs)->gso_segs;
340
341 seg = segs;
342 uh = udp_hdr(seg);
343
344 /* preserve TX timestamp flags and TS key for first segment */
345 skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
346 skb_shinfo(seg)->tx_flags |=
347 (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
348
349 /* compute checksum adjustment based on old length versus new */
350 newlen = htons(sizeof(*uh) + mss);
351 check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
352
353 for (;;) {
354 if (copy_dtor) {
355 seg->destructor = sock_wfree;
356 seg->sk = sk;
357 sum_truesize += seg->truesize;
358 }
359
360 if (!seg->next)
361 break;
362
363 uh->len = newlen;
364 uh->check = check;
365
366 if (seg->ip_summed == CHECKSUM_PARTIAL)
367 gso_reset_checksum(seg, ~check);
368 else
369 uh->check = gso_make_checksum(seg, ~check) ? :
370 CSUM_MANGLED_0;
371
372 seg = seg->next;
373 uh = udp_hdr(seg);
374 }
375
376 /* last packet can be partial gso_size, account for that in checksum */
377 newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
378 seg->data_len);
379 check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
380
381 uh->len = newlen;
382 uh->check = check;
383
384 if (seg->ip_summed == CHECKSUM_PARTIAL)
385 gso_reset_checksum(seg, ~check);
386 else
387 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
388
389 /* On the TX path, CHECKSUM_NONE and CHECKSUM_UNNECESSARY have the same
390 * meaning. However, check for bad offloads in the GSO stack expects the
391 * latter, if the checksum was calculated in software. To vouch for the
392 * segment skbs we actually need to set it on the gso_skb.
393 */
394 if (gso_skb->ip_summed == CHECKSUM_NONE)
395 gso_skb->ip_summed = CHECKSUM_UNNECESSARY;
396
397 /* update refcount for the packet */
398 if (copy_dtor) {
399 int delta = sum_truesize - gso_skb->truesize;
400
401 /* In some pathological cases, delta can be negative.
402 * We need to either use refcount_add() or refcount_sub_and_test()
403 */
404 if (likely(delta >= 0))
405 refcount_add(delta, &sk->sk_wmem_alloc);
406 else
407 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
408 }
409 return segs;
410 }
411 EXPORT_SYMBOL_GPL(__udp_gso_segment);
412
413 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
414 netdev_features_t features)
415 {
416 struct sk_buff *segs = ERR_PTR(-EINVAL);
417 unsigned int mss;
418 __wsum csum;
419 struct udphdr *uh;
420 struct iphdr *iph;
421
422 if (skb->encapsulation &&
423 (skb_shinfo(skb)->gso_type &
424 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
425 segs = skb_udp_tunnel_segment(skb, features, false);
426 goto out;
427 }
428
429 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
430 goto out;
431
432 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
433 goto out;
434
435 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
436 return __udp_gso_segment(skb, features, false);
437
438 mss = skb_shinfo(skb)->gso_size;
439 if (unlikely(skb->len <= mss))
440 goto out;
441
442 /* Do software UFO. Complete and fill in the UDP checksum as
443 * HW cannot do checksum of UDP packets sent as multiple
444 * IP fragments.
445 */
446
447 uh = udp_hdr(skb);
448 iph = ip_hdr(skb);
449
450 uh->check = 0;
451 csum = skb_checksum(skb, 0, skb->len, 0);
452 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
453 if (uh->check == 0)
454 uh->check = CSUM_MANGLED_0;
455
456 skb->ip_summed = CHECKSUM_UNNECESSARY;
457
458 /* If there is no outer header we can fake a checksum offload
459 * due to the fact that we have already done the checksum in
460 * software prior to segmenting the frame.
461 */
462 if (!skb->encap_hdr_csum)
463 features |= NETIF_F_HW_CSUM;
464
465 /* Fragment the skb. IP headers of the fragments are updated in
466 * inet_gso_segment()
467 */
468 segs = skb_segment(skb, features);
469 out:
470 return segs;
471 }
472
473
474 #define UDP_GRO_CNT_MAX 64
475 static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
476 struct sk_buff *skb)
477 {
478 struct udphdr *uh = udp_gro_udphdr(skb);
479 struct sk_buff *pp = NULL;
480 struct udphdr *uh2;
481 struct sk_buff *p;
482 unsigned int ulen;
483 int ret = 0;
484 int flush;
485
486 /* requires non zero csum, for symmetry with GSO */
487 if (!uh->check) {
488 NAPI_GRO_CB(skb)->flush = 1;
489 return NULL;
490 }
491
492 /* Do not deal with padded or malicious packets, sorry ! */
493 ulen = ntohs(uh->len);
494 if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
495 NAPI_GRO_CB(skb)->flush = 1;
496 return NULL;
497 }
498 /* pull encapsulating udp header */
499 skb_gro_pull(skb, sizeof(struct udphdr));
500
501 list_for_each_entry(p, head, list) {
502 if (!NAPI_GRO_CB(p)->same_flow)
503 continue;
504
505 uh2 = udp_hdr(p);
506
507 /* Match ports only, as csum is always non zero */
508 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
509 NAPI_GRO_CB(p)->same_flow = 0;
510 continue;
511 }
512
513 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
514 NAPI_GRO_CB(skb)->flush = 1;
515 return p;
516 }
517
518 flush = gro_receive_network_flush(uh, uh2, p);
519
520 /* Terminate the flow on len mismatch or if it grow "too much".
521 * Under small packet flood GRO count could elsewhere grow a lot
522 * leading to excessive truesize values.
523 * On len mismatch merge the first packet shorter than gso_size,
524 * otherwise complete the GRO packet.
525 */
526 if (ulen > ntohs(uh2->len) || flush) {
527 pp = p;
528 } else {
529 if (NAPI_GRO_CB(skb)->is_flist) {
530 if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
531 NAPI_GRO_CB(skb)->flush = 1;
532 return NULL;
533 }
534 if ((skb->ip_summed != p->ip_summed) ||
535 (skb->csum_level != p->csum_level)) {
536 NAPI_GRO_CB(skb)->flush = 1;
537 return NULL;
538 }
539 ret = skb_gro_receive_list(p, skb);
540 } else {
541 skb_gro_postpull_rcsum(skb, uh,
542 sizeof(struct udphdr));
543
544 ret = skb_gro_receive(p, skb);
545 }
546 }
547
548 if (ret || ulen != ntohs(uh2->len) ||
549 NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
550 pp = p;
551
552 return pp;
553 }
554
555 /* mismatch, but we never need to flush */
556 return NULL;
557 }
558
559 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
560 struct udphdr *uh, struct sock *sk)
561 {
562 struct sk_buff *pp = NULL;
563 struct sk_buff *p;
564 struct udphdr *uh2;
565 unsigned int off = skb_gro_offset(skb);
566 int flush = 1;
567
568 /* We can do L4 aggregation only if the packet can't land in a tunnel
569 * otherwise we could corrupt the inner stream. Detecting such packets
570 * cannot be foolproof and the aggregation might still happen in some
571 * cases. Such packets should be caught in udp_unexpected_gso later.
572 */
573 NAPI_GRO_CB(skb)->is_flist = 0;
574 if (!sk || !udp_sk(sk)->gro_receive) {
575 /* If the packet was locally encapsulated in a UDP tunnel that
576 * wasn't detected above, do not GRO.
577 */
578 if (skb->encapsulation)
579 goto out;
580
581 if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
582 NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1;
583
584 if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
585 (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist)
586 return call_gro_receive(udp_gro_receive_segment, head, skb);
587
588 /* no GRO, be sure flush the current packet */
589 goto out;
590 }
591
592 if (NAPI_GRO_CB(skb)->encap_mark ||
593 (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
594 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
595 !NAPI_GRO_CB(skb)->csum_valid))
596 goto out;
597
598 /* mark that this skb passed once through the tunnel gro layer */
599 NAPI_GRO_CB(skb)->encap_mark = 1;
600
601 flush = 0;
602
603 list_for_each_entry(p, head, list) {
604 if (!NAPI_GRO_CB(p)->same_flow)
605 continue;
606
607 uh2 = (struct udphdr *)(p->data + off);
608
609 /* Match ports and either checksums are either both zero
610 * or nonzero.
611 */
612 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
613 (!uh->check ^ !uh2->check)) {
614 NAPI_GRO_CB(p)->same_flow = 0;
615 continue;
616 }
617 }
618
619 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
620 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
621 pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
622
623 out:
624 skb_gro_flush_final(skb, pp, flush);
625 return pp;
626 }
627 EXPORT_SYMBOL(udp_gro_receive);
628
629 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
630 __be16 dport)
631 {
632 const struct iphdr *iph = skb_gro_network_header(skb);
633 struct net *net = dev_net(skb->dev);
634 int iif, sdif;
635
636 inet_get_iif_sdif(skb, &iif, &sdif);
637
638 return __udp4_lib_lookup(net, iph->saddr, sport,
639 iph->daddr, dport, iif,
640 sdif, net->ipv4.udp_table, NULL);
641 }
642
643 INDIRECT_CALLABLE_SCOPE
644 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
645 {
646 struct udphdr *uh = udp_gro_udphdr(skb);
647 struct sock *sk = NULL;
648 struct sk_buff *pp;
649
650 if (unlikely(!uh))
651 goto flush;
652
653 /* Don't bother verifying checksum if we're going to flush anyway. */
654 if (NAPI_GRO_CB(skb)->flush)
655 goto skip;
656
657 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
658 inet_gro_compute_pseudo))
659 goto flush;
660 else if (uh->check)
661 skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
662 inet_gro_compute_pseudo);
663 skip:
664 NAPI_GRO_CB(skb)->is_ipv6 = 0;
665
666 if (static_branch_unlikely(&udp_encap_needed_key))
667 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
668
669 pp = udp_gro_receive(head, skb, uh, sk);
670 return pp;
671
672 flush:
673 NAPI_GRO_CB(skb)->flush = 1;
674 return NULL;
675 }
676
677 static int udp_gro_complete_segment(struct sk_buff *skb)
678 {
679 struct udphdr *uh = udp_hdr(skb);
680
681 skb->csum_start = (unsigned char *)uh - skb->head;
682 skb->csum_offset = offsetof(struct udphdr, check);
683 skb->ip_summed = CHECKSUM_PARTIAL;
684
685 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
686 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
687
688 if (skb->encapsulation)
689 skb->inner_transport_header = skb->transport_header;
690
691 return 0;
692 }
693
694 int udp_gro_complete(struct sk_buff *skb, int nhoff,
695 udp_lookup_t lookup)
696 {
697 __be16 newlen = htons(skb->len - nhoff);
698 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
699 struct sock *sk;
700 int err;
701
702 uh->len = newlen;
703
704 sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
705 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
706 if (sk && udp_sk(sk)->gro_complete) {
707 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
708 : SKB_GSO_UDP_TUNNEL;
709
710 /* clear the encap mark, so that inner frag_list gro_complete
711 * can take place
712 */
713 NAPI_GRO_CB(skb)->encap_mark = 0;
714
715 /* Set encapsulation before calling into inner gro_complete()
716 * functions to make them set up the inner offsets.
717 */
718 skb->encapsulation = 1;
719 err = udp_sk(sk)->gro_complete(sk, skb,
720 nhoff + sizeof(struct udphdr));
721 } else {
722 err = udp_gro_complete_segment(skb);
723 }
724
725 if (skb->remcsum_offload)
726 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
727
728 return err;
729 }
730 EXPORT_SYMBOL(udp_gro_complete);
731
732 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
733 {
734 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
735 const struct iphdr *iph = (struct iphdr *)(skb->data + offset);
736 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
737
738 /* do fraglist only if there is no outer UDP encap (or we already processed it) */
739 if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
740 uh->len = htons(skb->len - nhoff);
741
742 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
743 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
744
745 __skb_incr_checksum_unnecessary(skb);
746
747 return 0;
748 }
749
750 if (uh->check)
751 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
752 iph->daddr, 0);
753
754 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
755 }
756
757 int __init udpv4_offload_init(void)
758 {
759 net_hotdata.udpv4_offload = (struct net_offload) {
760 .callbacks = {
761 .gso_segment = udp4_ufo_fragment,
762 .gro_receive = udp4_gro_receive,
763 .gro_complete = udp4_gro_complete,
764 },
765 };
766 return inet_add_offload(&net_hotdata.udpv4_offload, IPPROTO_UDP);
767 }
768
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