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))) || skb_sec_path(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
__udpv6_gso_segment_csum(struct sk_buff * seg,struct in6_addr * oldip,const struct in6_addr * newip,__be16 * oldport,__be16 newport)250 static void __udpv6_gso_segment_csum(struct sk_buff *seg,
251 struct in6_addr *oldip,
252 const struct in6_addr *newip,
253 __be16 *oldport, __be16 newport)
254 {
255 struct udphdr *uh = udp_hdr(seg);
256
257 if (ipv6_addr_equal(oldip, newip) && *oldport == newport)
258 return;
259
260 if (uh->check) {
261 inet_proto_csum_replace16(&uh->check, seg, oldip->s6_addr32,
262 newip->s6_addr32, true);
263
264 inet_proto_csum_replace2(&uh->check, seg, *oldport, newport,
265 false);
266 if (!uh->check)
267 uh->check = CSUM_MANGLED_0;
268 }
269
270 *oldip = *newip;
271 *oldport = newport;
272 }
273
__udpv6_gso_segment_list_csum(struct sk_buff * segs)274 static struct sk_buff *__udpv6_gso_segment_list_csum(struct sk_buff *segs)
275 {
276 const struct ipv6hdr *iph;
277 const struct udphdr *uh;
278 struct ipv6hdr *iph2;
279 struct sk_buff *seg;
280 struct udphdr *uh2;
281
282 seg = segs;
283 uh = udp_hdr(seg);
284 iph = ipv6_hdr(seg);
285 uh2 = udp_hdr(seg->next);
286 iph2 = ipv6_hdr(seg->next);
287
288 if (!(*(const u32 *)&uh->source ^ *(const u32 *)&uh2->source) &&
289 ipv6_addr_equal(&iph->saddr, &iph2->saddr) &&
290 ipv6_addr_equal(&iph->daddr, &iph2->daddr))
291 return segs;
292
293 while ((seg = seg->next)) {
294 uh2 = udp_hdr(seg);
295 iph2 = ipv6_hdr(seg);
296
297 __udpv6_gso_segment_csum(seg, &iph2->saddr, &iph->saddr,
298 &uh2->source, uh->source);
299 __udpv6_gso_segment_csum(seg, &iph2->daddr, &iph->daddr,
300 &uh2->dest, uh->dest);
301 }
302
303 return segs;
304 }
305
__udp_gso_segment_list(struct sk_buff * skb,netdev_features_t features,bool is_ipv6)306 static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
307 netdev_features_t features,
308 bool is_ipv6)
309 {
310 unsigned int mss = skb_shinfo(skb)->gso_size;
311
312 skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
313 if (IS_ERR(skb))
314 return skb;
315
316 udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
317
318 if (is_ipv6)
319 return __udpv6_gso_segment_list_csum(skb);
320 else
321 return __udpv4_gso_segment_list_csum(skb);
322 }
323
__udp_gso_segment(struct sk_buff * gso_skb,netdev_features_t features,bool is_ipv6)324 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
325 netdev_features_t features, bool is_ipv6)
326 {
327 struct sock *sk = gso_skb->sk;
328 unsigned int sum_truesize = 0;
329 struct sk_buff *segs, *seg;
330 struct udphdr *uh;
331 unsigned int mss;
332 bool copy_dtor;
333 __sum16 check;
334 __be16 newlen;
335 int ret = 0;
336
337 mss = skb_shinfo(gso_skb)->gso_size;
338 if (gso_skb->len <= sizeof(*uh) + mss)
339 return ERR_PTR(-EINVAL);
340
341 if (unlikely(skb_checksum_start(gso_skb) !=
342 skb_transport_header(gso_skb) &&
343 !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)))
344 return ERR_PTR(-EINVAL);
345
346 /* We don't know if egress device can segment and checksum the packet
347 * when IPv6 extension headers are present. Fall back to software GSO.
348 */
349 if (gso_skb->ip_summed != CHECKSUM_PARTIAL)
350 features &= ~(NETIF_F_GSO_UDP_L4 | NETIF_F_CSUM_MASK);
351
352 if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) {
353 /* Packet is from an untrusted source, reset gso_segs. */
354 skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh),
355 mss);
356 return NULL;
357 }
358
359 if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) {
360 /* Detect modified geometry and pass those to skb_segment. */
361 if (skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size)
362 return __udp_gso_segment_list(gso_skb, features, is_ipv6);
363
364 ret = __skb_linearize(gso_skb);
365 if (ret)
366 return ERR_PTR(ret);
367
368 /* Setup csum, as fraglist skips this in udp4_gro_receive. */
369 gso_skb->csum_start = skb_transport_header(gso_skb) - gso_skb->head;
370 gso_skb->csum_offset = offsetof(struct udphdr, check);
371 gso_skb->ip_summed = CHECKSUM_PARTIAL;
372
373 uh = udp_hdr(gso_skb);
374 if (is_ipv6)
375 uh->check = ~udp_v6_check(gso_skb->len,
376 &ipv6_hdr(gso_skb)->saddr,
377 &ipv6_hdr(gso_skb)->daddr, 0);
378 else
379 uh->check = ~udp_v4_check(gso_skb->len,
380 ip_hdr(gso_skb)->saddr,
381 ip_hdr(gso_skb)->daddr, 0);
382 }
383
384 skb_pull(gso_skb, sizeof(*uh));
385
386 /* clear destructor to avoid skb_segment assigning it to tail */
387 copy_dtor = gso_skb->destructor == sock_wfree;
388 if (copy_dtor) {
389 gso_skb->destructor = NULL;
390 gso_skb->sk = NULL;
391 }
392
393 segs = skb_segment(gso_skb, features);
394 if (IS_ERR_OR_NULL(segs)) {
395 if (copy_dtor) {
396 gso_skb->destructor = sock_wfree;
397 gso_skb->sk = sk;
398 }
399 return segs;
400 }
401
402 /* GSO partial and frag_list segmentation only requires splitting
403 * the frame into an MSS multiple and possibly a remainder, both
404 * cases return a GSO skb. So update the mss now.
405 */
406 if (skb_is_gso(segs))
407 mss *= skb_shinfo(segs)->gso_segs;
408
409 seg = segs;
410 uh = udp_hdr(seg);
411
412 /* preserve TX timestamp flags and TS key for first segment */
413 skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
414 skb_shinfo(seg)->tx_flags |=
415 (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
416
417 /* compute checksum adjustment based on old length versus new */
418 newlen = htons(sizeof(*uh) + mss);
419 check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
420
421 for (;;) {
422 if (copy_dtor) {
423 seg->destructor = sock_wfree;
424 seg->sk = sk;
425 sum_truesize += seg->truesize;
426 }
427
428 if (!seg->next)
429 break;
430
431 uh->len = newlen;
432 uh->check = check;
433
434 if (seg->ip_summed == CHECKSUM_PARTIAL)
435 gso_reset_checksum(seg, ~check);
436 else
437 uh->check = gso_make_checksum(seg, ~check) ? :
438 CSUM_MANGLED_0;
439
440 seg = seg->next;
441 uh = udp_hdr(seg);
442 }
443
444 /* last packet can be partial gso_size, account for that in checksum */
445 newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
446 seg->data_len);
447 check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
448
449 uh->len = newlen;
450 uh->check = check;
451
452 if (seg->ip_summed == CHECKSUM_PARTIAL)
453 gso_reset_checksum(seg, ~check);
454 else
455 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
456
457 /* On the TX path, CHECKSUM_NONE and CHECKSUM_UNNECESSARY have the same
458 * meaning. However, check for bad offloads in the GSO stack expects the
459 * latter, if the checksum was calculated in software. To vouch for the
460 * segment skbs we actually need to set it on the gso_skb.
461 */
462 if (gso_skb->ip_summed == CHECKSUM_NONE)
463 gso_skb->ip_summed = CHECKSUM_UNNECESSARY;
464
465 /* update refcount for the packet */
466 if (copy_dtor) {
467 int delta = sum_truesize - gso_skb->truesize;
468
469 /* In some pathological cases, delta can be negative.
470 * We need to either use refcount_add() or refcount_sub_and_test()
471 */
472 if (likely(delta >= 0))
473 refcount_add(delta, &sk->sk_wmem_alloc);
474 else
475 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
476 }
477 return segs;
478 }
479 EXPORT_SYMBOL_GPL(__udp_gso_segment);
480
udp4_ufo_fragment(struct sk_buff * skb,netdev_features_t features)481 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
482 netdev_features_t features)
483 {
484 struct sk_buff *segs = ERR_PTR(-EINVAL);
485 unsigned int mss;
486 __wsum csum;
487 struct udphdr *uh;
488 struct iphdr *iph;
489
490 if (skb->encapsulation &&
491 (skb_shinfo(skb)->gso_type &
492 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
493 segs = skb_udp_tunnel_segment(skb, features, false);
494 goto out;
495 }
496
497 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
498 goto out;
499
500 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
501 goto out;
502
503 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
504 return __udp_gso_segment(skb, features, false);
505
506 mss = skb_shinfo(skb)->gso_size;
507 if (unlikely(skb->len <= mss))
508 goto out;
509
510 /* Do software UFO. Complete and fill in the UDP checksum as
511 * HW cannot do checksum of UDP packets sent as multiple
512 * IP fragments.
513 */
514
515 uh = udp_hdr(skb);
516 iph = ip_hdr(skb);
517
518 uh->check = 0;
519 csum = skb_checksum(skb, 0, skb->len, 0);
520 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
521 if (uh->check == 0)
522 uh->check = CSUM_MANGLED_0;
523
524 skb->ip_summed = CHECKSUM_UNNECESSARY;
525
526 /* If there is no outer header we can fake a checksum offload
527 * due to the fact that we have already done the checksum in
528 * software prior to segmenting the frame.
529 */
530 if (!skb->encap_hdr_csum)
531 features |= NETIF_F_HW_CSUM;
532
533 /* Fragment the skb. IP headers of the fragments are updated in
534 * inet_gso_segment()
535 */
536 segs = skb_segment(skb, features);
537 out:
538 return segs;
539 }
540
541
542 #define UDP_GRO_CNT_MAX 64
udp_gro_receive_segment(struct list_head * head,struct sk_buff * skb)543 static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
544 struct sk_buff *skb)
545 {
546 struct udphdr *uh = udp_gro_udphdr(skb);
547 struct sk_buff *pp = NULL;
548 struct udphdr *uh2;
549 struct sk_buff *p;
550 unsigned int ulen;
551 int ret = 0;
552 int flush;
553
554 /* requires non zero csum, for symmetry with GSO */
555 if (!uh->check) {
556 NAPI_GRO_CB(skb)->flush = 1;
557 return NULL;
558 }
559
560 /* Do not deal with padded or malicious packets, sorry ! */
561 ulen = ntohs(uh->len);
562 if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
563 NAPI_GRO_CB(skb)->flush = 1;
564 return NULL;
565 }
566 /* pull encapsulating udp header */
567 skb_gro_pull(skb, sizeof(struct udphdr));
568
569 list_for_each_entry(p, head, list) {
570 if (!NAPI_GRO_CB(p)->same_flow)
571 continue;
572
573 uh2 = udp_hdr(p);
574
575 /* Match ports only, as csum is always non zero */
576 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
577 NAPI_GRO_CB(p)->same_flow = 0;
578 continue;
579 }
580
581 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
582 NAPI_GRO_CB(skb)->flush = 1;
583 return p;
584 }
585
586 flush = gro_receive_network_flush(uh, uh2, p);
587
588 /* Terminate the flow on len mismatch or if it grow "too much".
589 * Under small packet flood GRO count could elsewhere grow a lot
590 * leading to excessive truesize values.
591 * On len mismatch merge the first packet shorter than gso_size,
592 * otherwise complete the GRO packet.
593 */
594 if (ulen > ntohs(uh2->len) || flush) {
595 pp = p;
596 } else {
597 if (NAPI_GRO_CB(skb)->is_flist) {
598 if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
599 NAPI_GRO_CB(skb)->flush = 1;
600 return NULL;
601 }
602 if ((skb->ip_summed != p->ip_summed) ||
603 (skb->csum_level != p->csum_level)) {
604 NAPI_GRO_CB(skb)->flush = 1;
605 return NULL;
606 }
607 skb_set_network_header(skb, skb_gro_receive_network_offset(skb));
608 ret = skb_gro_receive_list(p, skb);
609 } else {
610 skb_gro_postpull_rcsum(skb, uh,
611 sizeof(struct udphdr));
612
613 ret = skb_gro_receive(p, skb);
614 }
615 }
616
617 if (ret || ulen != ntohs(uh2->len) ||
618 NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
619 pp = p;
620
621 return pp;
622 }
623
624 /* mismatch, but we never need to flush */
625 return NULL;
626 }
627
udp_gro_receive(struct list_head * head,struct sk_buff * skb,struct udphdr * uh,struct sock * sk)628 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
629 struct udphdr *uh, struct sock *sk)
630 {
631 struct sk_buff *pp = NULL;
632 struct sk_buff *p;
633 struct udphdr *uh2;
634 unsigned int off = skb_gro_offset(skb);
635 int flush = 1;
636
637 /* We can do L4 aggregation only if the packet can't land in a tunnel
638 * otherwise we could corrupt the inner stream. Detecting such packets
639 * cannot be foolproof and the aggregation might still happen in some
640 * cases. Such packets should be caught in udp_unexpected_gso later.
641 */
642 NAPI_GRO_CB(skb)->is_flist = 0;
643 if (!sk || !udp_sk(sk)->gro_receive) {
644 /* If the packet was locally encapsulated in a UDP tunnel that
645 * wasn't detected above, do not GRO.
646 */
647 if (skb->encapsulation)
648 goto out;
649
650 if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
651 NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1;
652
653 if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
654 (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist)
655 return call_gro_receive(udp_gro_receive_segment, head, skb);
656
657 /* no GRO, be sure flush the current packet */
658 goto out;
659 }
660
661 if (NAPI_GRO_CB(skb)->encap_mark ||
662 (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
663 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
664 !NAPI_GRO_CB(skb)->csum_valid))
665 goto out;
666
667 /* mark that this skb passed once through the tunnel gro layer */
668 NAPI_GRO_CB(skb)->encap_mark = 1;
669
670 flush = 0;
671
672 list_for_each_entry(p, head, list) {
673 if (!NAPI_GRO_CB(p)->same_flow)
674 continue;
675
676 uh2 = (struct udphdr *)(p->data + off);
677
678 /* Match ports and either checksums are either both zero
679 * or nonzero.
680 */
681 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
682 (!uh->check ^ !uh2->check)) {
683 NAPI_GRO_CB(p)->same_flow = 0;
684 continue;
685 }
686 }
687
688 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
689 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
690 pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
691
692 out:
693 skb_gro_flush_final(skb, pp, flush);
694 return pp;
695 }
696 EXPORT_SYMBOL(udp_gro_receive);
697
udp4_gro_lookup_skb(struct sk_buff * skb,__be16 sport,__be16 dport)698 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
699 __be16 dport)
700 {
701 const struct iphdr *iph = skb_gro_network_header(skb);
702 struct net *net = dev_net(skb->dev);
703 int iif, sdif;
704
705 inet_get_iif_sdif(skb, &iif, &sdif);
706
707 return __udp4_lib_lookup(net, iph->saddr, sport,
708 iph->daddr, dport, iif,
709 sdif, net->ipv4.udp_table, NULL);
710 }
711
712 INDIRECT_CALLABLE_SCOPE
udp4_gro_receive(struct list_head * head,struct sk_buff * skb)713 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
714 {
715 struct udphdr *uh = udp_gro_udphdr(skb);
716 struct sock *sk = NULL;
717 struct sk_buff *pp;
718
719 if (unlikely(!uh))
720 goto flush;
721
722 /* Don't bother verifying checksum if we're going to flush anyway. */
723 if (NAPI_GRO_CB(skb)->flush)
724 goto skip;
725
726 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
727 inet_gro_compute_pseudo))
728 goto flush;
729 else if (uh->check)
730 skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
731 inet_gro_compute_pseudo);
732 skip:
733 NAPI_GRO_CB(skb)->is_ipv6 = 0;
734
735 if (static_branch_unlikely(&udp_encap_needed_key))
736 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
737
738 pp = udp_gro_receive(head, skb, uh, sk);
739 return pp;
740
741 flush:
742 NAPI_GRO_CB(skb)->flush = 1;
743 return NULL;
744 }
745
udp_gro_complete_segment(struct sk_buff * skb)746 static int udp_gro_complete_segment(struct sk_buff *skb)
747 {
748 struct udphdr *uh = udp_hdr(skb);
749
750 skb->csum_start = (unsigned char *)uh - skb->head;
751 skb->csum_offset = offsetof(struct udphdr, check);
752 skb->ip_summed = CHECKSUM_PARTIAL;
753
754 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
755 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
756
757 if (skb->encapsulation)
758 skb->inner_transport_header = skb->transport_header;
759
760 return 0;
761 }
762
udp_gro_complete(struct sk_buff * skb,int nhoff,udp_lookup_t lookup)763 int udp_gro_complete(struct sk_buff *skb, int nhoff,
764 udp_lookup_t lookup)
765 {
766 __be16 newlen = htons(skb->len - nhoff);
767 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
768 struct sock *sk;
769 int err;
770
771 uh->len = newlen;
772
773 sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
774 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
775 if (sk && udp_sk(sk)->gro_complete) {
776 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
777 : SKB_GSO_UDP_TUNNEL;
778
779 /* clear the encap mark, so that inner frag_list gro_complete
780 * can take place
781 */
782 NAPI_GRO_CB(skb)->encap_mark = 0;
783
784 /* Set encapsulation before calling into inner gro_complete()
785 * functions to make them set up the inner offsets.
786 */
787 skb->encapsulation = 1;
788 err = udp_sk(sk)->gro_complete(sk, skb,
789 nhoff + sizeof(struct udphdr));
790 } else {
791 err = udp_gro_complete_segment(skb);
792 }
793
794 if (skb->remcsum_offload)
795 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
796
797 return err;
798 }
799 EXPORT_SYMBOL(udp_gro_complete);
800
udp4_gro_complete(struct sk_buff * skb,int nhoff)801 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
802 {
803 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
804 const struct iphdr *iph = (struct iphdr *)(skb->data + offset);
805 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
806
807 /* do fraglist only if there is no outer UDP encap (or we already processed it) */
808 if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
809 uh->len = htons(skb->len - nhoff);
810
811 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
812 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
813
814 __skb_incr_checksum_unnecessary(skb);
815
816 return 0;
817 }
818
819 if (uh->check)
820 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
821 iph->daddr, 0);
822
823 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
824 }
825
udpv4_offload_init(void)826 int __init udpv4_offload_init(void)
827 {
828 net_hotdata.udpv4_offload = (struct net_offload) {
829 .callbacks = {
830 .gso_segment = udp4_ufo_fragment,
831 .gro_receive = udp4_gro_receive,
832 .gro_complete = udp4_gro_complete,
833 },
834 };
835 return inet_add_offload(&net_hotdata.udpv4_offload, IPPROTO_UDP);
836 }
837