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 #include <net/udp_tunnel.h>
16
17 #if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
18
19 /*
20 * Dummy GRO tunnel callback, exists mainly to avoid dangling/NULL
21 * values for the udp tunnel static call.
22 */
dummy_gro_rcv(struct sock * sk,struct list_head * head,struct sk_buff * skb)23 static struct sk_buff *dummy_gro_rcv(struct sock *sk,
24 struct list_head *head,
25 struct sk_buff *skb)
26 {
27 NAPI_GRO_CB(skb)->flush = 1;
28 return NULL;
29 }
30
31 typedef struct sk_buff *(*udp_tunnel_gro_rcv_t)(struct sock *sk,
32 struct list_head *head,
33 struct sk_buff *skb);
34
35 struct udp_tunnel_type_entry {
36 udp_tunnel_gro_rcv_t gro_receive;
37 refcount_t count;
38 };
39
40 #define UDP_MAX_TUNNEL_TYPES (IS_ENABLED(CONFIG_GENEVE) + \
41 IS_ENABLED(CONFIG_VXLAN) * 2 + \
42 IS_ENABLED(CONFIG_NET_FOU) * 2 + \
43 IS_ENABLED(CONFIG_XFRM) * 2)
44
45 DEFINE_STATIC_CALL(udp_tunnel_gro_rcv, dummy_gro_rcv);
46 static DEFINE_STATIC_KEY_FALSE(udp_tunnel_static_call);
47 static DEFINE_MUTEX(udp_tunnel_gro_type_lock);
48 static struct udp_tunnel_type_entry udp_tunnel_gro_types[UDP_MAX_TUNNEL_TYPES];
49 static unsigned int udp_tunnel_gro_type_nr;
50 static DEFINE_SPINLOCK(udp_tunnel_gro_lock);
51
udp_tunnel_update_gro_lookup(struct net * net,struct sock * sk,bool add)52 void udp_tunnel_update_gro_lookup(struct net *net, struct sock *sk, bool add)
53 {
54 bool is_ipv6 = sk->sk_family == AF_INET6;
55 struct udp_sock *tup, *up = udp_sk(sk);
56 struct udp_tunnel_gro *udp_tunnel_gro;
57
58 spin_lock(&udp_tunnel_gro_lock);
59 udp_tunnel_gro = &net->ipv4.udp_tunnel_gro[is_ipv6];
60 if (add)
61 hlist_add_head(&up->tunnel_list, &udp_tunnel_gro->list);
62 else if (up->tunnel_list.pprev)
63 hlist_del_init(&up->tunnel_list);
64
65 if (udp_tunnel_gro->list.first &&
66 !udp_tunnel_gro->list.first->next) {
67 tup = hlist_entry(udp_tunnel_gro->list.first, struct udp_sock,
68 tunnel_list);
69
70 rcu_assign_pointer(udp_tunnel_gro->sk, (struct sock *)tup);
71 } else {
72 RCU_INIT_POINTER(udp_tunnel_gro->sk, NULL);
73 }
74
75 spin_unlock(&udp_tunnel_gro_lock);
76 }
77 EXPORT_SYMBOL_GPL(udp_tunnel_update_gro_lookup);
78
udp_tunnel_update_gro_rcv(struct sock * sk,bool add)79 void udp_tunnel_update_gro_rcv(struct sock *sk, bool add)
80 {
81 struct udp_tunnel_type_entry *cur = NULL;
82 struct udp_sock *up = udp_sk(sk);
83 int i, old_gro_type_nr;
84
85 if (!UDP_MAX_TUNNEL_TYPES || !up->gro_receive)
86 return;
87
88 mutex_lock(&udp_tunnel_gro_type_lock);
89
90 /* Check if the static call is permanently disabled. */
91 if (udp_tunnel_gro_type_nr > UDP_MAX_TUNNEL_TYPES)
92 goto out;
93
94 for (i = 0; i < udp_tunnel_gro_type_nr; i++)
95 if (udp_tunnel_gro_types[i].gro_receive == up->gro_receive)
96 cur = &udp_tunnel_gro_types[i];
97
98 old_gro_type_nr = udp_tunnel_gro_type_nr;
99 if (add) {
100 /*
101 * Update the matching entry, if found, or add a new one
102 * if needed
103 */
104 if (cur) {
105 refcount_inc(&cur->count);
106 goto out;
107 }
108
109 if (unlikely(udp_tunnel_gro_type_nr == UDP_MAX_TUNNEL_TYPES)) {
110 pr_err_once("Too many UDP tunnel types, please increase UDP_MAX_TUNNEL_TYPES\n");
111 /* Ensure static call will never be enabled */
112 udp_tunnel_gro_type_nr = UDP_MAX_TUNNEL_TYPES + 1;
113 } else {
114 cur = &udp_tunnel_gro_types[udp_tunnel_gro_type_nr++];
115 refcount_set(&cur->count, 1);
116 cur->gro_receive = up->gro_receive;
117 }
118 } else {
119 /*
120 * The stack cleanups only successfully added tunnel, the
121 * lookup on removal should never fail.
122 */
123 if (WARN_ON_ONCE(!cur))
124 goto out;
125
126 if (!refcount_dec_and_test(&cur->count))
127 goto out;
128
129 /* Avoid gaps, so that the enable tunnel has always id 0 */
130 *cur = udp_tunnel_gro_types[--udp_tunnel_gro_type_nr];
131 }
132
133 if (udp_tunnel_gro_type_nr == 1) {
134 static_call_update(udp_tunnel_gro_rcv,
135 udp_tunnel_gro_types[0].gro_receive);
136 static_branch_enable(&udp_tunnel_static_call);
137 } else if (old_gro_type_nr == 1) {
138 static_branch_disable(&udp_tunnel_static_call);
139 static_call_update(udp_tunnel_gro_rcv, dummy_gro_rcv);
140 }
141
142 out:
143 mutex_unlock(&udp_tunnel_gro_type_lock);
144 }
145 EXPORT_SYMBOL_GPL(udp_tunnel_update_gro_rcv);
146
udp_tunnel_gro_rcv(struct sock * sk,struct list_head * head,struct sk_buff * skb)147 static struct sk_buff *udp_tunnel_gro_rcv(struct sock *sk,
148 struct list_head *head,
149 struct sk_buff *skb)
150 {
151 if (static_branch_likely(&udp_tunnel_static_call)) {
152 if (unlikely(gro_recursion_inc_test(skb))) {
153 NAPI_GRO_CB(skb)->flush |= 1;
154 return NULL;
155 }
156 return static_call(udp_tunnel_gro_rcv)(sk, head, skb);
157 }
158 return call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
159 }
160
161 #else
162
udp_tunnel_gro_rcv(struct sock * sk,struct list_head * head,struct sk_buff * skb)163 static struct sk_buff *udp_tunnel_gro_rcv(struct sock *sk,
164 struct list_head *head,
165 struct sk_buff *skb)
166 {
167 return call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
168 }
169
170 #endif
171
__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)172 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
173 netdev_features_t features,
174 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
175 netdev_features_t features),
176 __be16 new_protocol, bool is_ipv6)
177 {
178 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
179 bool remcsum, need_csum, offload_csum, gso_partial;
180 struct sk_buff *segs = ERR_PTR(-EINVAL);
181 u16 mac_offset = skb->mac_header;
182 __be16 protocol = skb->protocol;
183 u16 mac_len = skb->mac_len;
184 int udp_offset, outer_hlen;
185 struct udphdr *uh;
186 __wsum partial;
187 bool need_ipsec;
188
189 if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
190 goto out;
191
192 uh = udp_hdr(skb);
193
194 /* Adjust partial header checksum to negate old length.
195 * We cannot rely on the value contained in uh->len as it is
196 * possible that the actual value exceeds the boundaries of the
197 * 16 bit length field due to the header being added outside of an
198 * IP or IPv6 frame that was already limited to 64K - 1.
199 */
200 if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
201 partial = (__force __wsum)uh->len;
202 else
203 partial = (__force __wsum)htonl(skb->len);
204 partial = csum_sub(csum_unfold(uh->check), partial);
205
206 /* setup inner skb. */
207 skb->encapsulation = 0;
208 SKB_GSO_CB(skb)->encap_level = 0;
209 __skb_pull(skb, tnl_hlen);
210 skb_reset_mac_header(skb);
211 skb_set_network_header(skb, skb_inner_network_offset(skb));
212 skb_set_transport_header(skb, skb_inner_transport_offset(skb));
213 skb->mac_len = skb_inner_network_offset(skb);
214 skb->protocol = new_protocol;
215
216 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
217 skb->encap_hdr_csum = need_csum;
218
219 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
220 skb->remcsum_offload = remcsum;
221
222 need_ipsec = (skb_dst(skb) && dst_xfrm(skb_dst(skb))) || skb_sec_path(skb);
223 /* Try to offload checksum if possible */
224 offload_csum = !!(need_csum &&
225 !need_ipsec &&
226 (skb->dev->features &
227 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
228 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
229
230 features &= skb->dev->hw_enc_features;
231 if (need_csum)
232 features &= ~NETIF_F_SCTP_CRC;
233
234 /* The only checksum offload we care about from here on out is the
235 * outer one so strip the existing checksum feature flags and
236 * instead set the flag based on our outer checksum offload value.
237 */
238 if (remcsum) {
239 features &= ~NETIF_F_CSUM_MASK;
240 if (!need_csum || offload_csum)
241 features |= NETIF_F_HW_CSUM;
242 }
243
244 /* segment inner packet. */
245 segs = gso_inner_segment(skb, features);
246 if (IS_ERR_OR_NULL(segs)) {
247 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
248 mac_len);
249 goto out;
250 }
251
252 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
253
254 outer_hlen = skb_tnl_header_len(skb);
255 udp_offset = outer_hlen - tnl_hlen;
256 skb = segs;
257 do {
258 unsigned int len;
259
260 if (remcsum)
261 skb->ip_summed = CHECKSUM_NONE;
262
263 /* Set up inner headers if we are offloading inner checksum */
264 if (skb->ip_summed == CHECKSUM_PARTIAL) {
265 skb_reset_inner_headers(skb);
266 skb->encapsulation = 1;
267 }
268
269 skb->mac_len = mac_len;
270 skb->protocol = protocol;
271
272 __skb_push(skb, outer_hlen);
273 skb_reset_mac_header(skb);
274 skb_set_network_header(skb, mac_len);
275 skb_set_transport_header(skb, udp_offset);
276 len = skb->len - udp_offset;
277 uh = udp_hdr(skb);
278
279 /* If we are only performing partial GSO the inner header
280 * will be using a length value equal to only one MSS sized
281 * segment instead of the entire frame.
282 */
283 if (gso_partial && skb_is_gso(skb)) {
284 udp_set_len_short(uh, skb_shinfo(skb)->gso_size +
285 SKB_GSO_CB(skb)->data_offset +
286 skb->head - (unsigned char *)uh);
287 } else {
288 udp_set_len_short(uh, len);
289 }
290
291 if (!need_csum)
292 continue;
293
294 uh->check = ~csum_fold(csum_add(partial,
295 (__force __wsum)htonl(len)));
296
297 if (skb->encapsulation || !offload_csum) {
298 uh->check = gso_make_checksum(skb, ~uh->check);
299 if (uh->check == 0)
300 uh->check = CSUM_MANGLED_0;
301 } else {
302 skb->ip_summed = CHECKSUM_PARTIAL;
303 skb->csum_start = skb_transport_header(skb) - skb->head;
304 skb->csum_offset = offsetof(struct udphdr, check);
305 }
306 } while ((skb = skb->next));
307 out:
308 return segs;
309 }
310
skb_udp_tunnel_segment(struct sk_buff * skb,netdev_features_t features,bool is_ipv6)311 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
312 netdev_features_t features,
313 bool is_ipv6)
314 {
315 const struct net_offload __rcu **offloads;
316 __be16 protocol = skb->protocol;
317 const struct net_offload *ops;
318 struct sk_buff *segs = ERR_PTR(-EINVAL);
319 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
320 netdev_features_t features);
321
322 rcu_read_lock();
323
324 switch (skb->inner_protocol_type) {
325 case ENCAP_TYPE_ETHER:
326 protocol = skb->inner_protocol;
327 gso_inner_segment = skb_mac_gso_segment;
328 break;
329 case ENCAP_TYPE_IPPROTO:
330 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
331 ops = rcu_dereference(offloads[skb->inner_ipproto]);
332 if (!ops || !ops->callbacks.gso_segment)
333 goto out_unlock;
334 gso_inner_segment = ops->callbacks.gso_segment;
335 break;
336 default:
337 goto out_unlock;
338 }
339
340 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
341 protocol, is_ipv6);
342
343 out_unlock:
344 rcu_read_unlock();
345
346 return segs;
347 }
348
__udpv4_gso_segment_csum(struct sk_buff * seg,__be32 * oldip,__be32 * newip,__be16 * oldport,__be16 * newport)349 static void __udpv4_gso_segment_csum(struct sk_buff *seg,
350 __be32 *oldip, __be32 *newip,
351 __be16 *oldport, __be16 *newport)
352 {
353 struct udphdr *uh;
354 struct iphdr *iph;
355
356 if (*oldip == *newip && *oldport == *newport)
357 return;
358
359 uh = udp_hdr(seg);
360 iph = ip_hdr(seg);
361
362 if (uh->check) {
363 inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
364 true);
365 inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
366 false);
367 if (!uh->check)
368 uh->check = CSUM_MANGLED_0;
369 }
370 *oldport = *newport;
371
372 csum_replace4(&iph->check, *oldip, *newip);
373 *oldip = *newip;
374 }
375
__udpv4_gso_segment_list_csum(struct sk_buff * segs)376 static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
377 {
378 struct sk_buff *seg;
379 struct udphdr *uh, *uh2;
380 struct iphdr *iph, *iph2;
381
382 seg = segs;
383 uh = udp_hdr(seg);
384 iph = ip_hdr(seg);
385
386 if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
387 (udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
388 (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
389 (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
390 return segs;
391
392 while ((seg = seg->next)) {
393 uh2 = udp_hdr(seg);
394 iph2 = ip_hdr(seg);
395
396 __udpv4_gso_segment_csum(seg,
397 &iph2->saddr, &iph->saddr,
398 &uh2->source, &uh->source);
399 __udpv4_gso_segment_csum(seg,
400 &iph2->daddr, &iph->daddr,
401 &uh2->dest, &uh->dest);
402 }
403
404 return segs;
405 }
406
__udpv6_gso_segment_csum(struct sk_buff * seg,struct in6_addr * oldip,const struct in6_addr * newip,__be16 * oldport,__be16 newport)407 static void __udpv6_gso_segment_csum(struct sk_buff *seg,
408 struct in6_addr *oldip,
409 const struct in6_addr *newip,
410 __be16 *oldport, __be16 newport)
411 {
412 struct udphdr *uh = udp_hdr(seg);
413
414 if (ipv6_addr_equal(oldip, newip) && *oldport == newport)
415 return;
416
417 if (uh->check) {
418 inet_proto_csum_replace16(&uh->check, seg, oldip->s6_addr32,
419 newip->s6_addr32, true);
420
421 inet_proto_csum_replace2(&uh->check, seg, *oldport, newport,
422 false);
423 if (!uh->check)
424 uh->check = CSUM_MANGLED_0;
425 }
426
427 *oldip = *newip;
428 *oldport = newport;
429 }
430
__udpv6_gso_segment_list_csum(struct sk_buff * segs)431 static struct sk_buff *__udpv6_gso_segment_list_csum(struct sk_buff *segs)
432 {
433 const struct ipv6hdr *iph;
434 const struct udphdr *uh;
435 struct ipv6hdr *iph2;
436 struct sk_buff *seg;
437 struct udphdr *uh2;
438
439 seg = segs;
440 uh = udp_hdr(seg);
441 iph = ipv6_hdr(seg);
442 uh2 = udp_hdr(seg->next);
443 iph2 = ipv6_hdr(seg->next);
444
445 if (!(*(const u32 *)&uh->source ^ *(const u32 *)&uh2->source) &&
446 ipv6_addr_equal(&iph->saddr, &iph2->saddr) &&
447 ipv6_addr_equal(&iph->daddr, &iph2->daddr))
448 return segs;
449
450 while ((seg = seg->next)) {
451 uh2 = udp_hdr(seg);
452 iph2 = ipv6_hdr(seg);
453
454 __udpv6_gso_segment_csum(seg, &iph2->saddr, &iph->saddr,
455 &uh2->source, uh->source);
456 __udpv6_gso_segment_csum(seg, &iph2->daddr, &iph->daddr,
457 &uh2->dest, uh->dest);
458 }
459
460 return segs;
461 }
462
__udp_gso_segment_list(struct sk_buff * skb,netdev_features_t features,bool is_ipv6)463 static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
464 netdev_features_t features,
465 bool is_ipv6)
466 {
467 unsigned int mss = skb_shinfo(skb)->gso_size;
468
469 skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
470 if (IS_ERR(skb))
471 return skb;
472
473 udp_set_len_short(udp_hdr(skb), sizeof(struct udphdr) + mss);
474
475 if (is_ipv6)
476 return __udpv6_gso_segment_list_csum(skb);
477 else
478 return __udpv4_gso_segment_list_csum(skb);
479 }
480
__udp_gso_segment(struct sk_buff * gso_skb,netdev_features_t features,bool is_ipv6)481 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
482 netdev_features_t features, bool is_ipv6)
483 {
484 struct sock *sk = gso_skb->sk;
485 unsigned int sum_truesize = 0;
486 struct sk_buff *segs, *seg;
487 struct udphdr *uh;
488 unsigned int mss;
489 bool copy_dtor;
490 __sum16 check;
491 int ret = 0;
492 u16 newlen;
493
494 mss = skb_shinfo(gso_skb)->gso_size;
495 if (gso_skb->len <= sizeof(*uh) + mss)
496 return ERR_PTR(-EINVAL);
497
498 if (unlikely(skb_checksum_start(gso_skb) !=
499 skb_transport_header(gso_skb) &&
500 !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)))
501 return ERR_PTR(-EINVAL);
502
503 /* We don't know if egress device can segment and checksum the packet
504 * when IPv6 extension headers are present. Fall back to software GSO.
505 */
506 if (gso_skb->ip_summed != CHECKSUM_PARTIAL)
507 features &= ~(NETIF_F_GSO_UDP_L4 | NETIF_F_CSUM_MASK);
508
509 if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) {
510 /* Packet is from an untrusted source, reset gso_segs. */
511 skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh),
512 mss);
513 return NULL;
514 }
515
516 if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) {
517 /* Detect modified geometry and pass those to skb_segment. */
518 if ((skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size) &&
519 !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_DODGY))
520 return __udp_gso_segment_list(gso_skb, features, is_ipv6);
521
522 ret = __skb_linearize(gso_skb);
523 if (ret)
524 return ERR_PTR(ret);
525
526 /* Setup csum, as fraglist skips this in udp4_gro_receive. */
527 gso_skb->csum_start = skb_transport_header(gso_skb) - gso_skb->head;
528 gso_skb->csum_offset = offsetof(struct udphdr, check);
529 gso_skb->ip_summed = CHECKSUM_PARTIAL;
530
531 uh = udp_hdr(gso_skb);
532 if (is_ipv6)
533 uh->check = ~udp_v6_check(gso_skb->len,
534 &ipv6_hdr(gso_skb)->saddr,
535 &ipv6_hdr(gso_skb)->daddr, 0);
536 else
537 uh->check = ~udp_v4_check(gso_skb->len,
538 ip_hdr(gso_skb)->saddr,
539 ip_hdr(gso_skb)->daddr, 0);
540 }
541
542 skb_pull(gso_skb, sizeof(*uh));
543
544 /* clear destructor to avoid skb_segment assigning it to tail */
545 copy_dtor = gso_skb->destructor == sock_wfree;
546 if (copy_dtor) {
547 gso_skb->destructor = NULL;
548 gso_skb->sk = NULL;
549 }
550
551 segs = skb_segment(gso_skb, features);
552 if (IS_ERR_OR_NULL(segs)) {
553 if (copy_dtor) {
554 gso_skb->destructor = sock_wfree;
555 gso_skb->sk = sk;
556 }
557 return segs;
558 }
559
560 seg = segs;
561 uh = udp_hdr(seg);
562
563 /* preserve TX timestamp flags and TS key for first segment */
564 skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
565 skb_shinfo(seg)->tx_flags |=
566 (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
567
568 /* compute checksum adjustment based on old length versus new */
569 newlen = sizeof(*uh) + mss;
570 check = csum16_add(csum16_sub(uh->check, uh->len), htons(newlen));
571
572 for (;;) {
573 if (copy_dtor) {
574 seg->destructor = sock_wfree;
575 seg->sk = sk;
576 sum_truesize += seg->truesize;
577 }
578
579 if (!seg->next)
580 break;
581
582 udp_set_len_short(uh, newlen);
583 uh->check = check;
584
585 if (seg->ip_summed == CHECKSUM_PARTIAL)
586 gso_reset_checksum(seg, ~check);
587 else
588 uh->check = gso_make_checksum(seg, ~check) ? :
589 CSUM_MANGLED_0;
590
591 seg = seg->next;
592 uh = udp_hdr(seg);
593 }
594
595 /* Unless skb fits perfectly as GSO_PARTIAL, the trailing
596 * segment may not be full MSS, account for that in the checksum
597 */
598 if (!skb_is_gso(seg))
599 newlen = skb_tail_pointer(seg) - skb_transport_header(seg) + seg->data_len;
600 check = csum16_add(csum16_sub(uh->check, uh->len), htons(newlen));
601
602 udp_set_len_short(uh, newlen);
603 uh->check = check;
604
605 if (seg->ip_summed == CHECKSUM_PARTIAL)
606 gso_reset_checksum(seg, ~check);
607 else
608 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
609
610 /* On the TX path, CHECKSUM_NONE and CHECKSUM_UNNECESSARY have the same
611 * meaning. However, check for bad offloads in the GSO stack expects the
612 * latter, if the checksum was calculated in software. To vouch for the
613 * segment skbs we actually need to set it on the gso_skb.
614 */
615 if (gso_skb->ip_summed == CHECKSUM_NONE)
616 gso_skb->ip_summed = CHECKSUM_UNNECESSARY;
617
618 /* update refcount for the packet */
619 if (copy_dtor) {
620 int delta = sum_truesize - gso_skb->truesize;
621
622 /* In some pathological cases, delta can be negative.
623 * We need to either use refcount_add() or refcount_sub_and_test()
624 */
625 if (likely(delta >= 0))
626 refcount_add(delta, &sk->sk_wmem_alloc);
627 else
628 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
629 }
630 return segs;
631 }
632
udp4_ufo_fragment(struct sk_buff * skb,netdev_features_t features)633 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
634 netdev_features_t features)
635 {
636 struct sk_buff *segs = ERR_PTR(-EINVAL);
637 unsigned int mss;
638 __wsum csum;
639 struct udphdr *uh;
640 struct iphdr *iph;
641
642 if (skb->encapsulation &&
643 (skb_shinfo(skb)->gso_type &
644 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
645 segs = skb_udp_tunnel_segment(skb, features, false);
646 goto out;
647 }
648
649 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
650 goto out;
651
652 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
653 goto out;
654
655 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
656 return __udp_gso_segment(skb, features, false);
657
658 mss = skb_shinfo(skb)->gso_size;
659 if (unlikely(skb->len <= mss))
660 goto out;
661
662 /* Do software UFO. Complete and fill in the UDP checksum as
663 * HW cannot do checksum of UDP packets sent as multiple
664 * IP fragments.
665 */
666
667 uh = udp_hdr(skb);
668 iph = ip_hdr(skb);
669
670 uh->check = 0;
671 csum = skb_checksum(skb, 0, skb->len, 0);
672 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
673 if (uh->check == 0)
674 uh->check = CSUM_MANGLED_0;
675
676 skb->ip_summed = CHECKSUM_UNNECESSARY;
677
678 /* If there is no outer header we can fake a checksum offload
679 * due to the fact that we have already done the checksum in
680 * software prior to segmenting the frame.
681 */
682 if (!skb->encap_hdr_csum)
683 features |= NETIF_F_HW_CSUM;
684
685 /* Fragment the skb. IP headers of the fragments are updated in
686 * inet_gso_segment()
687 */
688 segs = skb_segment(skb, features);
689 out:
690 return segs;
691 }
692
693
694 #define UDP_GRO_CNT_MAX 64
udp_gro_receive_segment(struct list_head * head,struct sk_buff * skb)695 static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
696 struct sk_buff *skb)
697 {
698 struct udphdr *uh = udp_gro_udphdr(skb);
699 struct sk_buff *pp = NULL;
700 struct udphdr *uh2;
701 struct sk_buff *p;
702 unsigned int ulen;
703 int ret = 0;
704 int flush;
705
706 /* requires non zero csum, for symmetry with GSO */
707 if (!uh->check) {
708 NAPI_GRO_CB(skb)->flush = 1;
709 return NULL;
710 }
711
712 ulen = udp_get_len_short(uh);
713
714 /* pull encapsulating udp header */
715 skb_gro_pull(skb, sizeof(struct udphdr));
716
717 list_for_each_entry(p, head, list) {
718 if (!NAPI_GRO_CB(p)->same_flow)
719 continue;
720
721 uh2 = udp_hdr(p);
722
723 /* Match ports only, as csum is always non zero */
724 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
725 NAPI_GRO_CB(p)->same_flow = 0;
726 continue;
727 }
728
729 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
730 NAPI_GRO_CB(skb)->flush = 1;
731 return p;
732 }
733
734 flush = gro_receive_network_flush(uh, uh2, p);
735
736 /* Terminate the flow on len mismatch or if it grow "too much".
737 * Under small packet flood GRO count could elsewhere grow a lot
738 * leading to excessive truesize values.
739 * On len mismatch merge the first packet shorter than gso_size,
740 * otherwise complete the GRO packet.
741 */
742 if (ulen > udp_get_len_short(uh2) || flush) {
743 pp = p;
744 } else {
745 if (NAPI_GRO_CB(skb)->is_flist) {
746 if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
747 NAPI_GRO_CB(skb)->flush = 1;
748 return NULL;
749 }
750 if ((skb->ip_summed != p->ip_summed) ||
751 (skb->csum_level != p->csum_level)) {
752 NAPI_GRO_CB(skb)->flush = 1;
753 return NULL;
754 }
755 skb_set_network_header(skb, skb_gro_receive_network_offset(skb));
756 ret = skb_gro_receive_list(p, skb);
757 } else {
758 skb_gro_postpull_rcsum(skb, uh,
759 sizeof(struct udphdr));
760
761 ret = skb_gro_receive(p, skb);
762 }
763 }
764
765 if (ret || ulen != udp_get_len_short(uh2) ||
766 NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
767 pp = p;
768
769 return pp;
770 }
771
772 /* mismatch, but we never need to flush */
773 return NULL;
774 }
775
udp_gro_receive(struct list_head * head,struct sk_buff * skb,struct udphdr * uh,struct sock * sk)776 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
777 struct udphdr *uh, struct sock *sk)
778 {
779 struct sk_buff *pp = NULL;
780 struct sk_buff *p;
781 struct udphdr *uh2;
782 unsigned int off = skb_gro_offset(skb);
783 unsigned int ulen;
784 int flush = 1;
785
786 /* Do not deal with padded or malicious packets, sorry! */
787 ulen = udp_get_len_short(uh);
788 if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb))
789 goto out;
790
791 /* We can do L4 aggregation only if the packet can't land in a tunnel
792 * otherwise we could corrupt the inner stream. Detecting such packets
793 * cannot be foolproof and the aggregation might still happen in some
794 * cases. Such packets should be caught in udp_unexpected_gso later.
795 */
796 NAPI_GRO_CB(skb)->is_flist = 0;
797 if (!sk || !udp_sk(sk)->gro_receive) {
798 /* If the packet was locally encapsulated in a UDP tunnel that
799 * wasn't detected above, do not GRO.
800 */
801 if (skb->encapsulation)
802 goto out;
803
804 if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
805 NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1;
806
807 if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
808 (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist)
809 return call_gro_receive(udp_gro_receive_segment, head, skb);
810
811 /* no GRO, be sure flush the current packet */
812 goto out;
813 }
814
815 if (NAPI_GRO_CB(skb)->encap_mark ||
816 (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
817 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
818 !NAPI_GRO_CB(skb)->csum_valid))
819 goto out;
820
821 /* mark that this skb passed once through the tunnel gro layer */
822 NAPI_GRO_CB(skb)->encap_mark = 1;
823
824 flush = 0;
825
826 list_for_each_entry(p, head, list) {
827 if (!NAPI_GRO_CB(p)->same_flow)
828 continue;
829
830 uh2 = (struct udphdr *)(p->data + off);
831
832 /* Match ports and either checksums are either both zero
833 * or nonzero.
834 */
835 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
836 (!uh->check ^ !uh2->check)) {
837 NAPI_GRO_CB(p)->same_flow = 0;
838 continue;
839 }
840 }
841
842 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
843 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
844 pp = udp_tunnel_gro_rcv(sk, head, skb);
845
846 out:
847 skb_gro_flush_final(skb, pp, flush);
848 return pp;
849 }
850
udp4_gro_lookup_skb(struct sk_buff * skb,__be16 sport,__be16 dport)851 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
852 __be16 dport)
853 {
854 const struct iphdr *iph = skb_gro_network_header(skb);
855 struct net *net = dev_net_rcu(skb->dev);
856 struct sock *sk;
857 int iif, sdif;
858
859 sk = udp_tunnel_sk(net, false);
860 if (sk && dport == htons(sk->sk_num))
861 return sk;
862
863 inet_get_iif_sdif(skb, &iif, &sdif);
864
865 return __udp4_lib_lookup(net, iph->saddr, sport,
866 iph->daddr, dport, iif, sdif, NULL);
867 }
868
869 INDIRECT_CALLABLE_SCOPE
udp4_gro_receive(struct list_head * head,struct sk_buff * skb)870 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
871 {
872 struct udphdr *uh = udp_gro_udphdr(skb);
873 struct sock *sk = NULL;
874 struct sk_buff *pp;
875
876 if (unlikely(!uh))
877 goto flush;
878
879 /* Don't bother verifying checksum if we're going to flush anyway. */
880 if (NAPI_GRO_CB(skb)->flush)
881 goto skip;
882
883 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
884 inet_gro_compute_pseudo))
885 goto flush;
886 else if (uh->check)
887 skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
888 inet_gro_compute_pseudo);
889 skip:
890 if (static_branch_unlikely(&udp_encap_needed_key))
891 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
892
893 pp = udp_gro_receive(head, skb, uh, sk);
894 return pp;
895
896 flush:
897 NAPI_GRO_CB(skb)->flush = 1;
898 return NULL;
899 }
900
udp_gro_complete_segment(struct sk_buff * skb)901 static int udp_gro_complete_segment(struct sk_buff *skb)
902 {
903 struct udphdr *uh = udp_hdr(skb);
904
905 skb->csum_start = (unsigned char *)uh - skb->head;
906 skb->csum_offset = offsetof(struct udphdr, check);
907 skb->ip_summed = CHECKSUM_PARTIAL;
908
909 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
910 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
911
912 if (skb->encapsulation)
913 skb->inner_transport_header = skb->transport_header;
914
915 return 0;
916 }
917
udp_gro_complete(struct sk_buff * skb,int nhoff,udp_lookup_t lookup)918 int udp_gro_complete(struct sk_buff *skb, int nhoff,
919 udp_lookup_t lookup)
920 {
921 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
922 unsigned int newlen = skb->len - nhoff;
923 struct sock *sk;
924 int err;
925
926 udp_set_len(uh, newlen);
927
928 sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
929 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
930 if (sk && udp_sk(sk)->gro_complete) {
931 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
932 : SKB_GSO_UDP_TUNNEL;
933
934 /* clear the encap mark, so that inner frag_list gro_complete
935 * can take place
936 */
937 NAPI_GRO_CB(skb)->encap_mark = 0;
938
939 /* Set encapsulation before calling into inner gro_complete()
940 * functions to make them set up the inner offsets.
941 */
942 skb->encapsulation = 1;
943 err = udp_sk(sk)->gro_complete(sk, skb,
944 nhoff + sizeof(struct udphdr));
945 } else {
946 err = udp_gro_complete_segment(skb);
947 }
948
949 if (skb->remcsum_offload)
950 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
951
952 return err;
953 }
954
udp4_gro_complete(struct sk_buff * skb,int nhoff)955 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
956 {
957 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
958 const struct iphdr *iph = (struct iphdr *)(skb->data + offset);
959 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
960
961 /* do fraglist only if there is no outer UDP encap (or we already processed it) */
962 if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
963 udp_set_len(uh, skb->len - nhoff);
964
965 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
966 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
967
968 __skb_incr_checksum_unnecessary(skb);
969
970 return 0;
971 }
972
973 if (uh->check)
974 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
975 iph->daddr, 0);
976
977 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
978 }
979
udpv4_offload_init(void)980 int __init udpv4_offload_init(void)
981 {
982 net_hotdata.udpv4_offload = (struct net_offload) {
983 .callbacks = {
984 .gso_segment = udp4_ufo_fragment,
985 .gro_receive = udp4_gro_receive,
986 .gro_complete = udp4_gro_complete,
987 },
988 };
989
990 return inet_add_offload(&net_hotdata.udpv4_offload, IPPROTO_UDP);
991 }
992