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
__skb_udp_tunnel_segment(struct sk_buff * skb,netdev_features_t features,struct sk_buff * (* gso_inner_segment)(struct sk_buff * skb,netdev_features_t features),__be16 new_protocol,bool is_ipv6)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
skb_udp_tunnel_segment(struct sk_buff * skb,netdev_features_t features,bool is_ipv6)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
__udpv4_gso_segment_csum(struct sk_buff * seg,__be32 * oldip,__be32 * newip,__be16 * oldport,__be16 * newport)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
__udpv4_gso_segment_list_csum(struct sk_buff * segs)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
__udp_gso_segment_list(struct sk_buff * skb,netdev_features_t features,bool is_ipv6)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
__udp_gso_segment(struct sk_buff * gso_skb,netdev_features_t features,bool is_ipv6)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 if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) {
287 /* Packet is from an untrusted source, reset gso_segs. */
288 skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh),
289 mss);
290 return NULL;
291 }
292
293 if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) {
294 /* Detect modified geometry and pass those to skb_segment. */
295 if (skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size)
296 return __udp_gso_segment_list(gso_skb, features, is_ipv6);
297
298 /* Setup csum, as fraglist skips this in udp4_gro_receive. */
299 gso_skb->csum_start = skb_transport_header(gso_skb) - gso_skb->head;
300 gso_skb->csum_offset = offsetof(struct udphdr, check);
301 gso_skb->ip_summed = CHECKSUM_PARTIAL;
302
303 uh = udp_hdr(gso_skb);
304 if (is_ipv6)
305 uh->check = ~udp_v6_check(gso_skb->len,
306 &ipv6_hdr(gso_skb)->saddr,
307 &ipv6_hdr(gso_skb)->daddr, 0);
308 else
309 uh->check = ~udp_v4_check(gso_skb->len,
310 ip_hdr(gso_skb)->saddr,
311 ip_hdr(gso_skb)->daddr, 0);
312 }
313
314 skb_pull(gso_skb, sizeof(*uh));
315
316 /* clear destructor to avoid skb_segment assigning it to tail */
317 copy_dtor = gso_skb->destructor == sock_wfree;
318 if (copy_dtor)
319 gso_skb->destructor = NULL;
320
321 segs = skb_segment(gso_skb, features);
322 if (IS_ERR_OR_NULL(segs)) {
323 if (copy_dtor)
324 gso_skb->destructor = sock_wfree;
325 return segs;
326 }
327
328 /* GSO partial and frag_list segmentation only requires splitting
329 * the frame into an MSS multiple and possibly a remainder, both
330 * cases return a GSO skb. So update the mss now.
331 */
332 if (skb_is_gso(segs))
333 mss *= skb_shinfo(segs)->gso_segs;
334
335 seg = segs;
336 uh = udp_hdr(seg);
337
338 /* preserve TX timestamp flags and TS key for first segment */
339 skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
340 skb_shinfo(seg)->tx_flags |=
341 (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
342
343 /* compute checksum adjustment based on old length versus new */
344 newlen = htons(sizeof(*uh) + mss);
345 check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
346
347 for (;;) {
348 if (copy_dtor) {
349 seg->destructor = sock_wfree;
350 seg->sk = sk;
351 sum_truesize += seg->truesize;
352 }
353
354 if (!seg->next)
355 break;
356
357 uh->len = newlen;
358 uh->check = check;
359
360 if (seg->ip_summed == CHECKSUM_PARTIAL)
361 gso_reset_checksum(seg, ~check);
362 else
363 uh->check = gso_make_checksum(seg, ~check) ? :
364 CSUM_MANGLED_0;
365
366 seg = seg->next;
367 uh = udp_hdr(seg);
368 }
369
370 /* last packet can be partial gso_size, account for that in checksum */
371 newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
372 seg->data_len);
373 check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
374
375 uh->len = newlen;
376 uh->check = check;
377
378 if (seg->ip_summed == CHECKSUM_PARTIAL)
379 gso_reset_checksum(seg, ~check);
380 else
381 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
382
383 /* update refcount for the packet */
384 if (copy_dtor) {
385 int delta = sum_truesize - gso_skb->truesize;
386
387 /* In some pathological cases, delta can be negative.
388 * We need to either use refcount_add() or refcount_sub_and_test()
389 */
390 if (likely(delta >= 0))
391 refcount_add(delta, &sk->sk_wmem_alloc);
392 else
393 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
394 }
395 return segs;
396 }
397 EXPORT_SYMBOL_GPL(__udp_gso_segment);
398
udp4_ufo_fragment(struct sk_buff * skb,netdev_features_t features)399 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
400 netdev_features_t features)
401 {
402 struct sk_buff *segs = ERR_PTR(-EINVAL);
403 unsigned int mss;
404 __wsum csum;
405 struct udphdr *uh;
406 struct iphdr *iph;
407
408 if (skb->encapsulation &&
409 (skb_shinfo(skb)->gso_type &
410 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
411 segs = skb_udp_tunnel_segment(skb, features, false);
412 goto out;
413 }
414
415 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
416 goto out;
417
418 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
419 goto out;
420
421 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
422 return __udp_gso_segment(skb, features, false);
423
424 mss = skb_shinfo(skb)->gso_size;
425 if (unlikely(skb->len <= mss))
426 goto out;
427
428 /* Do software UFO. Complete and fill in the UDP checksum as
429 * HW cannot do checksum of UDP packets sent as multiple
430 * IP fragments.
431 */
432
433 uh = udp_hdr(skb);
434 iph = ip_hdr(skb);
435
436 uh->check = 0;
437 csum = skb_checksum(skb, 0, skb->len, 0);
438 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
439 if (uh->check == 0)
440 uh->check = CSUM_MANGLED_0;
441
442 skb->ip_summed = CHECKSUM_UNNECESSARY;
443
444 /* If there is no outer header we can fake a checksum offload
445 * due to the fact that we have already done the checksum in
446 * software prior to segmenting the frame.
447 */
448 if (!skb->encap_hdr_csum)
449 features |= NETIF_F_HW_CSUM;
450
451 /* Fragment the skb. IP headers of the fragments are updated in
452 * inet_gso_segment()
453 */
454 segs = skb_segment(skb, features);
455 out:
456 return segs;
457 }
458
skb_gro_receive_list(struct sk_buff * p,struct sk_buff * skb)459 static int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
460 {
461 if (unlikely(p->len + skb->len >= 65536))
462 return -E2BIG;
463
464 if (NAPI_GRO_CB(p)->last == p)
465 skb_shinfo(p)->frag_list = skb;
466 else
467 NAPI_GRO_CB(p)->last->next = skb;
468
469 skb_pull(skb, skb_gro_offset(skb));
470
471 NAPI_GRO_CB(p)->last = skb;
472 NAPI_GRO_CB(p)->count++;
473 p->data_len += skb->len;
474
475 /* sk ownership - if any - completely transferred to the aggregated packet */
476 skb->destructor = NULL;
477 skb->sk = NULL;
478 p->truesize += skb->truesize;
479 p->len += skb->len;
480
481 NAPI_GRO_CB(skb)->same_flow = 1;
482
483 return 0;
484 }
485
486
487 #define UDP_GRO_CNT_MAX 64
udp_gro_receive_segment(struct list_head * head,struct sk_buff * skb)488 static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
489 struct sk_buff *skb)
490 {
491 struct udphdr *uh = udp_gro_udphdr(skb);
492 struct sk_buff *pp = NULL;
493 struct udphdr *uh2;
494 struct sk_buff *p;
495 unsigned int ulen;
496 int ret = 0;
497 int flush;
498
499 /* requires non zero csum, for symmetry with GSO */
500 if (!uh->check) {
501 NAPI_GRO_CB(skb)->flush = 1;
502 return NULL;
503 }
504
505 /* Do not deal with padded or malicious packets, sorry ! */
506 ulen = ntohs(uh->len);
507 if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
508 NAPI_GRO_CB(skb)->flush = 1;
509 return NULL;
510 }
511 /* pull encapsulating udp header */
512 skb_gro_pull(skb, sizeof(struct udphdr));
513
514 list_for_each_entry(p, head, list) {
515 if (!NAPI_GRO_CB(p)->same_flow)
516 continue;
517
518 uh2 = udp_hdr(p);
519
520 /* Match ports only, as csum is always non zero */
521 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
522 NAPI_GRO_CB(p)->same_flow = 0;
523 continue;
524 }
525
526 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
527 NAPI_GRO_CB(skb)->flush = 1;
528 return p;
529 }
530
531 flush = NAPI_GRO_CB(p)->flush;
532
533 if (NAPI_GRO_CB(p)->flush_id != 1 ||
534 NAPI_GRO_CB(p)->count != 1 ||
535 !NAPI_GRO_CB(p)->is_atomic)
536 flush |= NAPI_GRO_CB(p)->flush_id;
537 else
538 NAPI_GRO_CB(p)->is_atomic = false;
539
540 /* Terminate the flow on len mismatch or if it grow "too much".
541 * Under small packet flood GRO count could elsewhere grow a lot
542 * leading to excessive truesize values.
543 * On len mismatch merge the first packet shorter than gso_size,
544 * otherwise complete the GRO packet.
545 */
546 if (ulen > ntohs(uh2->len) || flush) {
547 pp = p;
548 } else {
549 if (NAPI_GRO_CB(skb)->is_flist) {
550 if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
551 NAPI_GRO_CB(skb)->flush = 1;
552 return NULL;
553 }
554 if ((skb->ip_summed != p->ip_summed) ||
555 (skb->csum_level != p->csum_level)) {
556 NAPI_GRO_CB(skb)->flush = 1;
557 return NULL;
558 }
559 ret = skb_gro_receive_list(p, skb);
560 } else {
561 skb_gro_postpull_rcsum(skb, uh,
562 sizeof(struct udphdr));
563
564 ret = skb_gro_receive(p, skb);
565 }
566 }
567
568 if (ret || ulen != ntohs(uh2->len) ||
569 NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
570 pp = p;
571
572 return pp;
573 }
574
575 /* mismatch, but we never need to flush */
576 return NULL;
577 }
578
udp_gro_receive(struct list_head * head,struct sk_buff * skb,struct udphdr * uh,struct sock * sk)579 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
580 struct udphdr *uh, struct sock *sk)
581 {
582 struct sk_buff *pp = NULL;
583 struct sk_buff *p;
584 struct udphdr *uh2;
585 unsigned int off = skb_gro_offset(skb);
586 int flush = 1;
587
588 /* We can do L4 aggregation only if the packet can't land in a tunnel
589 * otherwise we could corrupt the inner stream. Detecting such packets
590 * cannot be foolproof and the aggregation might still happen in some
591 * cases. Such packets should be caught in udp_unexpected_gso later.
592 */
593 NAPI_GRO_CB(skb)->is_flist = 0;
594 if (!sk || !udp_sk(sk)->gro_receive) {
595 /* If the packet was locally encapsulated in a UDP tunnel that
596 * wasn't detected above, do not GRO.
597 */
598 if (skb->encapsulation)
599 goto out;
600
601 if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
602 NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1;
603
604 if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
605 (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist)
606 return call_gro_receive(udp_gro_receive_segment, head, skb);
607
608 /* no GRO, be sure flush the current packet */
609 goto out;
610 }
611
612 if (NAPI_GRO_CB(skb)->encap_mark ||
613 (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
614 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
615 !NAPI_GRO_CB(skb)->csum_valid))
616 goto out;
617
618 /* mark that this skb passed once through the tunnel gro layer */
619 NAPI_GRO_CB(skb)->encap_mark = 1;
620
621 flush = 0;
622
623 list_for_each_entry(p, head, list) {
624 if (!NAPI_GRO_CB(p)->same_flow)
625 continue;
626
627 uh2 = (struct udphdr *)(p->data + off);
628
629 /* Match ports and either checksums are either both zero
630 * or nonzero.
631 */
632 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
633 (!uh->check ^ !uh2->check)) {
634 NAPI_GRO_CB(p)->same_flow = 0;
635 continue;
636 }
637 }
638
639 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
640 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
641 pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
642
643 out:
644 skb_gro_flush_final(skb, pp, flush);
645 return pp;
646 }
647 EXPORT_SYMBOL(udp_gro_receive);
648
udp4_gro_lookup_skb(struct sk_buff * skb,__be16 sport,__be16 dport)649 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
650 __be16 dport)
651 {
652 const struct iphdr *iph = skb_gro_network_header(skb);
653 struct net *net = dev_net(skb->dev);
654 int iif, sdif;
655
656 inet_get_iif_sdif(skb, &iif, &sdif);
657
658 return __udp4_lib_lookup(net, iph->saddr, sport,
659 iph->daddr, dport, iif,
660 sdif, net->ipv4.udp_table, NULL);
661 }
662
663 INDIRECT_CALLABLE_SCOPE
udp4_gro_receive(struct list_head * head,struct sk_buff * skb)664 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
665 {
666 struct udphdr *uh = udp_gro_udphdr(skb);
667 struct sock *sk = NULL;
668 struct sk_buff *pp;
669
670 if (unlikely(!uh))
671 goto flush;
672
673 /* Don't bother verifying checksum if we're going to flush anyway. */
674 if (NAPI_GRO_CB(skb)->flush)
675 goto skip;
676
677 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
678 inet_gro_compute_pseudo))
679 goto flush;
680 else if (uh->check)
681 skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
682 inet_gro_compute_pseudo);
683 skip:
684 NAPI_GRO_CB(skb)->is_ipv6 = 0;
685
686 if (static_branch_unlikely(&udp_encap_needed_key))
687 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
688
689 pp = udp_gro_receive(head, skb, uh, sk);
690 return pp;
691
692 flush:
693 NAPI_GRO_CB(skb)->flush = 1;
694 return NULL;
695 }
696
udp_gro_complete_segment(struct sk_buff * skb)697 static int udp_gro_complete_segment(struct sk_buff *skb)
698 {
699 struct udphdr *uh = udp_hdr(skb);
700
701 skb->csum_start = (unsigned char *)uh - skb->head;
702 skb->csum_offset = offsetof(struct udphdr, check);
703 skb->ip_summed = CHECKSUM_PARTIAL;
704
705 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
706 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
707
708 if (skb->encapsulation)
709 skb->inner_transport_header = skb->transport_header;
710
711 return 0;
712 }
713
udp_gro_complete(struct sk_buff * skb,int nhoff,udp_lookup_t lookup)714 int udp_gro_complete(struct sk_buff *skb, int nhoff,
715 udp_lookup_t lookup)
716 {
717 __be16 newlen = htons(skb->len - nhoff);
718 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
719 struct sock *sk;
720 int err;
721
722 uh->len = newlen;
723
724 sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
725 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
726 if (sk && udp_sk(sk)->gro_complete) {
727 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
728 : SKB_GSO_UDP_TUNNEL;
729
730 /* clear the encap mark, so that inner frag_list gro_complete
731 * can take place
732 */
733 NAPI_GRO_CB(skb)->encap_mark = 0;
734
735 /* Set encapsulation before calling into inner gro_complete()
736 * functions to make them set up the inner offsets.
737 */
738 skb->encapsulation = 1;
739 err = udp_sk(sk)->gro_complete(sk, skb,
740 nhoff + sizeof(struct udphdr));
741 } else {
742 err = udp_gro_complete_segment(skb);
743 }
744
745 if (skb->remcsum_offload)
746 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
747
748 return err;
749 }
750 EXPORT_SYMBOL(udp_gro_complete);
751
udp4_gro_complete(struct sk_buff * skb,int nhoff)752 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
753 {
754 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
755 const struct iphdr *iph = (struct iphdr *)(skb->data + offset);
756 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
757
758 /* do fraglist only if there is no outer UDP encap (or we already processed it) */
759 if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
760 uh->len = htons(skb->len - nhoff);
761
762 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
763 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
764
765 __skb_incr_checksum_unnecessary(skb);
766
767 return 0;
768 }
769
770 if (uh->check)
771 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
772 iph->daddr, 0);
773
774 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
775 }
776
777 static const struct net_offload udpv4_offload = {
778 .callbacks = {
779 .gso_segment = udp4_ufo_fragment,
780 .gro_receive = udp4_gro_receive,
781 .gro_complete = udp4_gro_complete,
782 },
783 };
784
udpv4_offload_init(void)785 int __init udpv4_offload_init(void)
786 {
787 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
788 }
789