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dm writecache: fix incorrect flush sequence when doing SSD mode commit
[linux/fpc-iii.git] / net / ipv4 / udp_offload.c
bloba3908e55ed89aa519ab761f3e4690819efe7ff33
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/udp.h>
11 #include <net/protocol.h>
12 #include <net/inet_common.h>
13
14 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
15 netdev_features_t features,
16 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
17 netdev_features_t features),
18 __be16 new_protocol, bool is_ipv6)
19 {
20 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
21 bool remcsum, need_csum, offload_csum, gso_partial;
22 struct sk_buff *segs = ERR_PTR(-EINVAL);
23 struct udphdr *uh = udp_hdr(skb);
24 u16 mac_offset = skb->mac_header;
25 __be16 protocol = skb->protocol;
26 u16 mac_len = skb->mac_len;
27 int udp_offset, outer_hlen;
28 __wsum partial;
29 bool need_ipsec;
30
31 if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
32 goto out;
33
34 /* Adjust partial header checksum to negate old length.
35 * We cannot rely on the value contained in uh->len as it is
36 * possible that the actual value exceeds the boundaries of the
37 * 16 bit length field due to the header being added outside of an
38 * IP or IPv6 frame that was already limited to 64K - 1.
39 */
40 if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
41 partial = (__force __wsum)uh->len;
42 else
43 partial = (__force __wsum)htonl(skb->len);
44 partial = csum_sub(csum_unfold(uh->check), partial);
45
46 /* setup inner skb. */
47 skb->encapsulation = 0;
48 SKB_GSO_CB(skb)->encap_level = 0;
49 __skb_pull(skb, tnl_hlen);
50 skb_reset_mac_header(skb);
51 skb_set_network_header(skb, skb_inner_network_offset(skb));
52 skb->mac_len = skb_inner_network_offset(skb);
53 skb->protocol = new_protocol;
54
55 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
56 skb->encap_hdr_csum = need_csum;
57
58 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
59 skb->remcsum_offload = remcsum;
60
61 need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
62 /* Try to offload checksum if possible */
63 offload_csum = !!(need_csum &&
64 !need_ipsec &&
65 (skb->dev->features &
66 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
67 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
68
69 features &= skb->dev->hw_enc_features;
70
71 /* The only checksum offload we care about from here on out is the
72 * outer one so strip the existing checksum feature flags and
73 * instead set the flag based on our outer checksum offload value.
74 */
75 if (remcsum) {
76 features &= ~NETIF_F_CSUM_MASK;
77 if (!need_csum || offload_csum)
78 features |= NETIF_F_HW_CSUM;
79 }
80
81 /* segment inner packet. */
82 segs = gso_inner_segment(skb, features);
83 if (IS_ERR_OR_NULL(segs)) {
84 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
85 mac_len);
86 goto out;
87 }
88
89 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
90
91 outer_hlen = skb_tnl_header_len(skb);
92 udp_offset = outer_hlen - tnl_hlen;
93 skb = segs;
94 do {
95 unsigned int len;
96
97 if (remcsum)
98 skb->ip_summed = CHECKSUM_NONE;
99
100 /* Set up inner headers if we are offloading inner checksum */
101 if (skb->ip_summed == CHECKSUM_PARTIAL) {
102 skb_reset_inner_headers(skb);
103 skb->encapsulation = 1;
104 }
105
106 skb->mac_len = mac_len;
107 skb->protocol = protocol;
108
109 __skb_push(skb, outer_hlen);
110 skb_reset_mac_header(skb);
111 skb_set_network_header(skb, mac_len);
112 skb_set_transport_header(skb, udp_offset);
113 len = skb->len - udp_offset;
114 uh = udp_hdr(skb);
115
116 /* If we are only performing partial GSO the inner header
117 * will be using a length value equal to only one MSS sized
118 * segment instead of the entire frame.
119 */
120 if (gso_partial && skb_is_gso(skb)) {
121 uh->len = htons(skb_shinfo(skb)->gso_size +
122 SKB_GSO_CB(skb)->data_offset +
123 skb->head - (unsigned char *)uh);
124 } else {
125 uh->len = htons(len);
126 }
127
128 if (!need_csum)
129 continue;
130
131 uh->check = ~csum_fold(csum_add(partial,
132 (__force __wsum)htonl(len)));
133
134 if (skb->encapsulation || !offload_csum) {
135 uh->check = gso_make_checksum(skb, ~uh->check);
136 if (uh->check == 0)
137 uh->check = CSUM_MANGLED_0;
138 } else {
139 skb->ip_summed = CHECKSUM_PARTIAL;
140 skb->csum_start = skb_transport_header(skb) - skb->head;
141 skb->csum_offset = offsetof(struct udphdr, check);
142 }
143 } while ((skb = skb->next));
144 out:
145 return segs;
146 }
147
148 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
149 netdev_features_t features,
150 bool is_ipv6)
151 {
152 __be16 protocol = skb->protocol;
153 const struct net_offload **offloads;
154 const struct net_offload *ops;
155 struct sk_buff *segs = ERR_PTR(-EINVAL);
156 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
157 netdev_features_t features);
158
159 rcu_read_lock();
160
161 switch (skb->inner_protocol_type) {
162 case ENCAP_TYPE_ETHER:
163 protocol = skb->inner_protocol;
164 gso_inner_segment = skb_mac_gso_segment;
165 break;
166 case ENCAP_TYPE_IPPROTO:
167 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
168 ops = rcu_dereference(offloads[skb->inner_ipproto]);
169 if (!ops || !ops->callbacks.gso_segment)
170 goto out_unlock;
171 gso_inner_segment = ops->callbacks.gso_segment;
172 break;
173 default:
174 goto out_unlock;
175 }
176
177 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
178 protocol, is_ipv6);
179
180 out_unlock:
181 rcu_read_unlock();
182
183 return segs;
184 }
185 EXPORT_SYMBOL(skb_udp_tunnel_segment);
186
187 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
188 netdev_features_t features)
189 {
190 struct sock *sk = gso_skb->sk;
191 unsigned int sum_truesize = 0;
192 struct sk_buff *segs, *seg;
193 struct udphdr *uh;
194 unsigned int mss;
195 bool copy_dtor;
196 __sum16 check;
197 __be16 newlen;
198
199 mss = skb_shinfo(gso_skb)->gso_size;
200 if (gso_skb->len <= sizeof(*uh) + mss)
201 return ERR_PTR(-EINVAL);
202
203 skb_pull(gso_skb, sizeof(*uh));
204
205 /* clear destructor to avoid skb_segment assigning it to tail */
206 copy_dtor = gso_skb->destructor == sock_wfree;
207 if (copy_dtor)
208 gso_skb->destructor = NULL;
209
210 segs = skb_segment(gso_skb, features);
211 if (IS_ERR_OR_NULL(segs)) {
212 if (copy_dtor)
213 gso_skb->destructor = sock_wfree;
214 return segs;
215 }
216
217 /* GSO partial and frag_list segmentation only requires splitting
218 * the frame into an MSS multiple and possibly a remainder, both
219 * cases return a GSO skb. So update the mss now.
220 */
221 if (skb_is_gso(segs))
222 mss *= skb_shinfo(segs)->gso_segs;
223
224 seg = segs;
225 uh = udp_hdr(seg);
226
227 /* preserve TX timestamp flags and TS key for first segment */
228 skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
229 skb_shinfo(seg)->tx_flags |=
230 (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
231
232 /* compute checksum adjustment based on old length versus new */
233 newlen = htons(sizeof(*uh) + mss);
234 check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
235
236 for (;;) {
237 if (copy_dtor) {
238 seg->destructor = sock_wfree;
239 seg->sk = sk;
240 sum_truesize += seg->truesize;
241 }
242
243 if (!seg->next)
244 break;
245
246 uh->len = newlen;
247 uh->check = check;
248
249 if (seg->ip_summed == CHECKSUM_PARTIAL)
250 gso_reset_checksum(seg, ~check);
251 else
252 uh->check = gso_make_checksum(seg, ~check) ? :
253 CSUM_MANGLED_0;
254
255 seg = seg->next;
256 uh = udp_hdr(seg);
257 }
258
259 /* last packet can be partial gso_size, account for that in checksum */
260 newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
261 seg->data_len);
262 check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
263
264 uh->len = newlen;
265 uh->check = check;
266
267 if (seg->ip_summed == CHECKSUM_PARTIAL)
268 gso_reset_checksum(seg, ~check);
269 else
270 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
271
272 /* update refcount for the packet */
273 if (copy_dtor) {
274 int delta = sum_truesize - gso_skb->truesize;
275
276 /* In some pathological cases, delta can be negative.
277 * We need to either use refcount_add() or refcount_sub_and_test()
278 */
279 if (likely(delta >= 0))
280 refcount_add(delta, &sk->sk_wmem_alloc);
281 else
282 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
283 }
284 return segs;
285 }
286 EXPORT_SYMBOL_GPL(__udp_gso_segment);
287
288 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
289 netdev_features_t features)
290 {
291 struct sk_buff *segs = ERR_PTR(-EINVAL);
292 unsigned int mss;
293 __wsum csum;
294 struct udphdr *uh;
295 struct iphdr *iph;
296
297 if (skb->encapsulation &&
298 (skb_shinfo(skb)->gso_type &
299 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
300 segs = skb_udp_tunnel_segment(skb, features, false);
301 goto out;
302 }
303
304 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
305 goto out;
306
307 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
308 goto out;
309
310 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
311 return __udp_gso_segment(skb, features);
312
313 mss = skb_shinfo(skb)->gso_size;
314 if (unlikely(skb->len <= mss))
315 goto out;
316
317 /* Do software UFO. Complete and fill in the UDP checksum as
318 * HW cannot do checksum of UDP packets sent as multiple
319 * IP fragments.
320 */
321
322 uh = udp_hdr(skb);
323 iph = ip_hdr(skb);
324
325 uh->check = 0;
326 csum = skb_checksum(skb, 0, skb->len, 0);
327 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
328 if (uh->check == 0)
329 uh->check = CSUM_MANGLED_0;
330
331 skb->ip_summed = CHECKSUM_UNNECESSARY;
332
333 /* If there is no outer header we can fake a checksum offload
334 * due to the fact that we have already done the checksum in
335 * software prior to segmenting the frame.
336 */
337 if (!skb->encap_hdr_csum)
338 features |= NETIF_F_HW_CSUM;
339
340 /* Fragment the skb. IP headers of the fragments are updated in
341 * inet_gso_segment()
342 */
343 segs = skb_segment(skb, features);
344 out:
345 return segs;
346 }
347
348 #define UDP_GRO_CNT_MAX 64
349 static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
350 struct sk_buff *skb)
351 {
352 struct udphdr *uh = udp_hdr(skb);
353 struct sk_buff *pp = NULL;
354 struct udphdr *uh2;
355 struct sk_buff *p;
356 unsigned int ulen;
357
358 /* requires non zero csum, for symmetry with GSO */
359 if (!uh->check) {
360 NAPI_GRO_CB(skb)->flush = 1;
361 return NULL;
362 }
363
364 /* Do not deal with padded or malicious packets, sorry ! */
365 ulen = ntohs(uh->len);
366 if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
367 NAPI_GRO_CB(skb)->flush = 1;
368 return NULL;
369 }
370 /* pull encapsulating udp header */
371 skb_gro_pull(skb, sizeof(struct udphdr));
372 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
373
374 list_for_each_entry(p, head, list) {
375 if (!NAPI_GRO_CB(p)->same_flow)
376 continue;
377
378 uh2 = udp_hdr(p);
379
380 /* Match ports only, as csum is always non zero */
381 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
382 NAPI_GRO_CB(p)->same_flow = 0;
383 continue;
384 }
385
386 /* Terminate the flow on len mismatch or if it grow "too much".
387 * Under small packet flood GRO count could elsewhere grow a lot
388 * leading to excessive truesize values.
389 * On len mismatch merge the first packet shorter than gso_size,
390 * otherwise complete the GRO packet.
391 */
392 if (ulen > ntohs(uh2->len) || skb_gro_receive(p, skb) ||
393 ulen != ntohs(uh2->len) ||
394 NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
395 pp = p;
396
397 return pp;
398 }
399
400 /* mismatch, but we never need to flush */
401 return NULL;
402 }
403
404 INDIRECT_CALLABLE_DECLARE(struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
405 __be16 sport, __be16 dport));
406 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
407 struct udphdr *uh, udp_lookup_t lookup)
408 {
409 struct sk_buff *pp = NULL;
410 struct sk_buff *p;
411 struct udphdr *uh2;
412 unsigned int off = skb_gro_offset(skb);
413 int flush = 1;
414 struct sock *sk;
415
416 rcu_read_lock();
417 sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
418 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
419 if (!sk)
420 goto out_unlock;
421
422 if (udp_sk(sk)->gro_enabled) {
423 pp = call_gro_receive(udp_gro_receive_segment, head, skb);
424 rcu_read_unlock();
425 return pp;
426 }
427
428 if (NAPI_GRO_CB(skb)->encap_mark ||
429 (skb->ip_summed != CHECKSUM_PARTIAL &&
430 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
431 !NAPI_GRO_CB(skb)->csum_valid) ||
432 !udp_sk(sk)->gro_receive)
433 goto out_unlock;
434
435 /* mark that this skb passed once through the tunnel gro layer */
436 NAPI_GRO_CB(skb)->encap_mark = 1;
437
438 flush = 0;
439
440 list_for_each_entry(p, head, list) {
441 if (!NAPI_GRO_CB(p)->same_flow)
442 continue;
443
444 uh2 = (struct udphdr *)(p->data + off);
445
446 /* Match ports and either checksums are either both zero
447 * or nonzero.
448 */
449 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
450 (!uh->check ^ !uh2->check)) {
451 NAPI_GRO_CB(p)->same_flow = 0;
452 continue;
453 }
454 }
455
456 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
457 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
458 pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
459
460 out_unlock:
461 rcu_read_unlock();
462 skb_gro_flush_final(skb, pp, flush);
463 return pp;
464 }
465 EXPORT_SYMBOL(udp_gro_receive);
466
467 INDIRECT_CALLABLE_SCOPE
468 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
469 {
470 struct udphdr *uh = udp_gro_udphdr(skb);
471
472 if (unlikely(!uh) || !static_branch_unlikely(&udp_encap_needed_key))
473 goto flush;
474
475 /* Don't bother verifying checksum if we're going to flush anyway. */
476 if (NAPI_GRO_CB(skb)->flush)
477 goto skip;
478
479 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
480 inet_gro_compute_pseudo))
481 goto flush;
482 else if (uh->check)
483 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
484 inet_gro_compute_pseudo);
485 skip:
486 NAPI_GRO_CB(skb)->is_ipv6 = 0;
487 return udp_gro_receive(head, skb, uh, udp4_lib_lookup_skb);
488
489 flush:
490 NAPI_GRO_CB(skb)->flush = 1;
491 return NULL;
492 }
493
494 static int udp_gro_complete_segment(struct sk_buff *skb)
495 {
496 struct udphdr *uh = udp_hdr(skb);
497
498 skb->csum_start = (unsigned char *)uh - skb->head;
499 skb->csum_offset = offsetof(struct udphdr, check);
500 skb->ip_summed = CHECKSUM_PARTIAL;
501
502 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
503 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
504 return 0;
505 }
506
507 int udp_gro_complete(struct sk_buff *skb, int nhoff,
508 udp_lookup_t lookup)
509 {
510 __be16 newlen = htons(skb->len - nhoff);
511 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
512 int err = -ENOSYS;
513 struct sock *sk;
514
515 uh->len = newlen;
516
517 rcu_read_lock();
518 sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
519 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
520 if (sk && udp_sk(sk)->gro_enabled) {
521 err = udp_gro_complete_segment(skb);
522 } else if (sk && udp_sk(sk)->gro_complete) {
523 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
524 : SKB_GSO_UDP_TUNNEL;
525
526 /* Set encapsulation before calling into inner gro_complete()
527 * functions to make them set up the inner offsets.
528 */
529 skb->encapsulation = 1;
530 err = udp_sk(sk)->gro_complete(sk, skb,
531 nhoff + sizeof(struct udphdr));
532 }
533 rcu_read_unlock();
534
535 if (skb->remcsum_offload)
536 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
537
538 return err;
539 }
540 EXPORT_SYMBOL(udp_gro_complete);
541
542 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
543 {
544 const struct iphdr *iph = ip_hdr(skb);
545 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
546
547 if (uh->check)
548 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
549 iph->daddr, 0);
550
551 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
552 }
553
554 static const struct net_offload udpv4_offload = {
555 .callbacks = {
556 .gso_segment = udp4_ufo_fragment,
557 .gro_receive = udp4_gro_receive,
558 .gro_complete = udp4_gro_complete,
559 },
560 };
561
562 int __init udpv4_offload_init(void)
563 {
564 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
565 }
Linux with added FPC-III support