1 // SPDX-License-Identifier: GPL-2.0-or-later
2 #include <net/gro.h>
3 #include <net/dst_metadata.h>
4 #include <net/busy_poll.h>
5 #include <trace/events/net.h>
6 #include <linux/skbuff_ref.h>
7
8 #define MAX_GRO_SKBS 8
9
10 /* This should be increased if a protocol with a bigger head is added. */
11 #define GRO_MAX_HEAD (MAX_HEADER + 128)
12
13 static DEFINE_SPINLOCK(offload_lock);
14
15 /**
16 * dev_add_offload - register offload handlers
17 * @po: protocol offload declaration
18 *
19 * Add protocol offload handlers to the networking stack. The passed
20 * &proto_offload is linked into kernel lists and may not be freed until
21 * it has been removed from the kernel lists.
22 *
23 * This call does not sleep therefore it can not
24 * guarantee all CPU's that are in middle of receiving packets
25 * will see the new offload handlers (until the next received packet).
26 */
dev_add_offload(struct packet_offload * po)27 void dev_add_offload(struct packet_offload *po)
28 {
29 struct packet_offload *elem;
30
31 spin_lock(&offload_lock);
32 list_for_each_entry(elem, &net_hotdata.offload_base, list) {
33 if (po->priority < elem->priority)
34 break;
35 }
36 list_add_rcu(&po->list, elem->list.prev);
37 spin_unlock(&offload_lock);
38 }
39 EXPORT_SYMBOL(dev_add_offload);
40
41 /**
42 * __dev_remove_offload - remove offload handler
43 * @po: packet offload declaration
44 *
45 * Remove a protocol offload handler that was previously added to the
46 * kernel offload handlers by dev_add_offload(). The passed &offload_type
47 * is removed from the kernel lists and can be freed or reused once this
48 * function returns.
49 *
50 * The packet type might still be in use by receivers
51 * and must not be freed until after all the CPU's have gone
52 * through a quiescent state.
53 */
__dev_remove_offload(struct packet_offload * po)54 static void __dev_remove_offload(struct packet_offload *po)
55 {
56 struct list_head *head = &net_hotdata.offload_base;
57 struct packet_offload *po1;
58
59 spin_lock(&offload_lock);
60
61 list_for_each_entry(po1, head, list) {
62 if (po == po1) {
63 list_del_rcu(&po->list);
64 goto out;
65 }
66 }
67
68 pr_warn("dev_remove_offload: %p not found\n", po);
69 out:
70 spin_unlock(&offload_lock);
71 }
72
73 /**
74 * dev_remove_offload - remove packet offload handler
75 * @po: packet offload declaration
76 *
77 * Remove a packet offload handler that was previously added to the kernel
78 * offload handlers by dev_add_offload(). The passed &offload_type is
79 * removed from the kernel lists and can be freed or reused once this
80 * function returns.
81 *
82 * This call sleeps to guarantee that no CPU is looking at the packet
83 * type after return.
84 */
dev_remove_offload(struct packet_offload * po)85 void dev_remove_offload(struct packet_offload *po)
86 {
87 __dev_remove_offload(po);
88
89 synchronize_net();
90 }
91 EXPORT_SYMBOL(dev_remove_offload);
92
93
skb_gro_receive(struct sk_buff * p,struct sk_buff * skb)94 int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
95 {
96 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb);
97 unsigned int offset = skb_gro_offset(skb);
98 unsigned int headlen = skb_headlen(skb);
99 unsigned int len = skb_gro_len(skb);
100 unsigned int delta_truesize;
101 unsigned int new_truesize;
102 struct sk_buff *lp;
103 int segs;
104
105 /* Do not splice page pool based packets w/ non-page pool
106 * packets. This can result in reference count issues as page
107 * pool pages will not decrement the reference count and will
108 * instead be immediately returned to the pool or have frag
109 * count decremented.
110 */
111 if (p->pp_recycle != skb->pp_recycle)
112 return -ETOOMANYREFS;
113
114 if (unlikely(p->len + len >= netif_get_gro_max_size(p->dev, p) ||
115 NAPI_GRO_CB(skb)->flush))
116 return -E2BIG;
117
118 if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) {
119 if (NAPI_GRO_CB(skb)->proto != IPPROTO_TCP ||
120 (p->protocol == htons(ETH_P_IPV6) &&
121 skb_headroom(p) < sizeof(struct hop_jumbo_hdr)) ||
122 p->encapsulation)
123 return -E2BIG;
124 }
125
126 segs = NAPI_GRO_CB(skb)->count;
127 lp = NAPI_GRO_CB(p)->last;
128 pinfo = skb_shinfo(lp);
129
130 if (headlen <= offset) {
131 skb_frag_t *frag;
132 skb_frag_t *frag2;
133 int i = skbinfo->nr_frags;
134 int nr_frags = pinfo->nr_frags + i;
135
136 if (nr_frags > MAX_SKB_FRAGS)
137 goto merge;
138
139 offset -= headlen;
140 pinfo->nr_frags = nr_frags;
141 skbinfo->nr_frags = 0;
142
143 frag = pinfo->frags + nr_frags;
144 frag2 = skbinfo->frags + i;
145 do {
146 *--frag = *--frag2;
147 } while (--i);
148
149 skb_frag_off_add(frag, offset);
150 skb_frag_size_sub(frag, offset);
151
152 /* all fragments truesize : remove (head size + sk_buff) */
153 new_truesize = SKB_TRUESIZE(skb_end_offset(skb));
154 delta_truesize = skb->truesize - new_truesize;
155
156 skb->truesize = new_truesize;
157 skb->len -= skb->data_len;
158 skb->data_len = 0;
159
160 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
161 goto done;
162 } else if (skb->head_frag) {
163 int nr_frags = pinfo->nr_frags;
164 skb_frag_t *frag = pinfo->frags + nr_frags;
165 struct page *page = virt_to_head_page(skb->head);
166 unsigned int first_size = headlen - offset;
167 unsigned int first_offset;
168
169 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
170 goto merge;
171
172 first_offset = skb->data -
173 (unsigned char *)page_address(page) +
174 offset;
175
176 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
177
178 skb_frag_fill_page_desc(frag, page, first_offset, first_size);
179
180 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
181 /* We dont need to clear skbinfo->nr_frags here */
182
183 new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff));
184 delta_truesize = skb->truesize - new_truesize;
185 skb->truesize = new_truesize;
186 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
187 goto done;
188 }
189
190 merge:
191 /* sk ownership - if any - completely transferred to the aggregated packet */
192 skb->destructor = NULL;
193 skb->sk = NULL;
194 delta_truesize = skb->truesize;
195 if (offset > headlen) {
196 unsigned int eat = offset - headlen;
197
198 skb_frag_off_add(&skbinfo->frags[0], eat);
199 skb_frag_size_sub(&skbinfo->frags[0], eat);
200 skb->data_len -= eat;
201 skb->len -= eat;
202 offset = headlen;
203 }
204
205 __skb_pull(skb, offset);
206
207 if (NAPI_GRO_CB(p)->last == p)
208 skb_shinfo(p)->frag_list = skb;
209 else
210 NAPI_GRO_CB(p)->last->next = skb;
211 NAPI_GRO_CB(p)->last = skb;
212 __skb_header_release(skb);
213 lp = p;
214
215 done:
216 NAPI_GRO_CB(p)->count += segs;
217 p->data_len += len;
218 p->truesize += delta_truesize;
219 p->len += len;
220 if (lp != p) {
221 lp->data_len += len;
222 lp->truesize += delta_truesize;
223 lp->len += len;
224 }
225 NAPI_GRO_CB(skb)->same_flow = 1;
226 return 0;
227 }
228
skb_gro_receive_list(struct sk_buff * p,struct sk_buff * skb)229 int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
230 {
231 if (unlikely(p->len + skb->len >= 65536))
232 return -E2BIG;
233
234 if (NAPI_GRO_CB(p)->last == p)
235 skb_shinfo(p)->frag_list = skb;
236 else
237 NAPI_GRO_CB(p)->last->next = skb;
238
239 skb_pull(skb, skb_gro_offset(skb));
240
241 NAPI_GRO_CB(p)->last = skb;
242 NAPI_GRO_CB(p)->count++;
243 p->data_len += skb->len;
244
245 /* sk ownership - if any - completely transferred to the aggregated packet */
246 skb->destructor = NULL;
247 skb->sk = NULL;
248 p->truesize += skb->truesize;
249 p->len += skb->len;
250
251 NAPI_GRO_CB(skb)->same_flow = 1;
252
253 return 0;
254 }
255
256
napi_gro_complete(struct napi_struct * napi,struct sk_buff * skb)257 static void napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb)
258 {
259 struct list_head *head = &net_hotdata.offload_base;
260 struct packet_offload *ptype;
261 __be16 type = skb->protocol;
262 int err = -ENOENT;
263
264 BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb));
265
266 if (NAPI_GRO_CB(skb)->count == 1) {
267 skb_shinfo(skb)->gso_size = 0;
268 goto out;
269 }
270
271 rcu_read_lock();
272 list_for_each_entry_rcu(ptype, head, list) {
273 if (ptype->type != type || !ptype->callbacks.gro_complete)
274 continue;
275
276 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
277 ipv6_gro_complete, inet_gro_complete,
278 skb, 0);
279 break;
280 }
281 rcu_read_unlock();
282
283 if (err) {
284 WARN_ON(&ptype->list == head);
285 kfree_skb(skb);
286 return;
287 }
288
289 out:
290 gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count);
291 }
292
__napi_gro_flush_chain(struct napi_struct * napi,u32 index,bool flush_old)293 static void __napi_gro_flush_chain(struct napi_struct *napi, u32 index,
294 bool flush_old)
295 {
296 struct list_head *head = &napi->gro_hash[index].list;
297 struct sk_buff *skb, *p;
298
299 list_for_each_entry_safe_reverse(skb, p, head, list) {
300 if (flush_old && NAPI_GRO_CB(skb)->age == jiffies)
301 return;
302 skb_list_del_init(skb);
303 napi_gro_complete(napi, skb);
304 napi->gro_hash[index].count--;
305 }
306
307 if (!napi->gro_hash[index].count)
308 __clear_bit(index, &napi->gro_bitmask);
309 }
310
311 /* napi->gro_hash[].list contains packets ordered by age.
312 * youngest packets at the head of it.
313 * Complete skbs in reverse order to reduce latencies.
314 */
napi_gro_flush(struct napi_struct * napi,bool flush_old)315 void napi_gro_flush(struct napi_struct *napi, bool flush_old)
316 {
317 unsigned long bitmask = napi->gro_bitmask;
318 unsigned int i, base = ~0U;
319
320 while ((i = ffs(bitmask)) != 0) {
321 bitmask >>= i;
322 base += i;
323 __napi_gro_flush_chain(napi, base, flush_old);
324 }
325 }
326 EXPORT_SYMBOL(napi_gro_flush);
327
gro_list_prepare_tc_ext(const struct sk_buff * skb,const struct sk_buff * p,unsigned long diffs)328 static unsigned long gro_list_prepare_tc_ext(const struct sk_buff *skb,
329 const struct sk_buff *p,
330 unsigned long diffs)
331 {
332 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
333 struct tc_skb_ext *skb_ext;
334 struct tc_skb_ext *p_ext;
335
336 skb_ext = skb_ext_find(skb, TC_SKB_EXT);
337 p_ext = skb_ext_find(p, TC_SKB_EXT);
338
339 diffs |= (!!p_ext) ^ (!!skb_ext);
340 if (!diffs && unlikely(skb_ext))
341 diffs |= p_ext->chain ^ skb_ext->chain;
342 #endif
343 return diffs;
344 }
345
gro_list_prepare(const struct list_head * head,const struct sk_buff * skb)346 static void gro_list_prepare(const struct list_head *head,
347 const struct sk_buff *skb)
348 {
349 unsigned int maclen = skb->dev->hard_header_len;
350 u32 hash = skb_get_hash_raw(skb);
351 struct sk_buff *p;
352
353 list_for_each_entry(p, head, list) {
354 unsigned long diffs;
355
356 if (hash != skb_get_hash_raw(p)) {
357 NAPI_GRO_CB(p)->same_flow = 0;
358 continue;
359 }
360
361 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
362 diffs |= p->vlan_all ^ skb->vlan_all;
363 diffs |= skb_metadata_differs(p, skb);
364 if (maclen == ETH_HLEN)
365 diffs |= compare_ether_header(skb_mac_header(p),
366 skb_mac_header(skb));
367 else if (!diffs)
368 diffs = memcmp(skb_mac_header(p),
369 skb_mac_header(skb),
370 maclen);
371
372 /* in most common scenarios 'slow_gro' is 0
373 * otherwise we are already on some slower paths
374 * either skip all the infrequent tests altogether or
375 * avoid trying too hard to skip each of them individually
376 */
377 if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) {
378 diffs |= p->sk != skb->sk;
379 diffs |= skb_metadata_dst_cmp(p, skb);
380 diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb);
381
382 diffs |= gro_list_prepare_tc_ext(skb, p, diffs);
383 }
384
385 NAPI_GRO_CB(p)->same_flow = !diffs;
386 }
387 }
388
skb_gro_reset_offset(struct sk_buff * skb,u32 nhoff)389 static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff)
390 {
391 const struct skb_shared_info *pinfo;
392 const skb_frag_t *frag0;
393 unsigned int headlen;
394
395 NAPI_GRO_CB(skb)->network_offset = 0;
396 NAPI_GRO_CB(skb)->data_offset = 0;
397 headlen = skb_headlen(skb);
398 NAPI_GRO_CB(skb)->frag0 = skb->data;
399 NAPI_GRO_CB(skb)->frag0_len = headlen;
400 if (headlen)
401 return;
402
403 pinfo = skb_shinfo(skb);
404 frag0 = &pinfo->frags[0];
405
406 if (pinfo->nr_frags && skb_frag_page(frag0) &&
407 !PageHighMem(skb_frag_page(frag0)) &&
408 (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) {
409 NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0);
410 NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int,
411 skb_frag_size(frag0),
412 skb->end - skb->tail);
413 }
414 }
415
gro_pull_from_frag0(struct sk_buff * skb,int grow)416 static void gro_pull_from_frag0(struct sk_buff *skb, int grow)
417 {
418 struct skb_shared_info *pinfo = skb_shinfo(skb);
419
420 BUG_ON(skb->end - skb->tail < grow);
421
422 memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow);
423
424 skb->data_len -= grow;
425 skb->tail += grow;
426
427 skb_frag_off_add(&pinfo->frags[0], grow);
428 skb_frag_size_sub(&pinfo->frags[0], grow);
429
430 if (unlikely(!skb_frag_size(&pinfo->frags[0]))) {
431 skb_frag_unref(skb, 0);
432 memmove(pinfo->frags, pinfo->frags + 1,
433 --pinfo->nr_frags * sizeof(pinfo->frags[0]));
434 }
435 }
436
gro_try_pull_from_frag0(struct sk_buff * skb)437 static void gro_try_pull_from_frag0(struct sk_buff *skb)
438 {
439 int grow = skb_gro_offset(skb) - skb_headlen(skb);
440
441 if (grow > 0)
442 gro_pull_from_frag0(skb, grow);
443 }
444
gro_flush_oldest(struct napi_struct * napi,struct list_head * head)445 static void gro_flush_oldest(struct napi_struct *napi, struct list_head *head)
446 {
447 struct sk_buff *oldest;
448
449 oldest = list_last_entry(head, struct sk_buff, list);
450
451 /* We are called with head length >= MAX_GRO_SKBS, so this is
452 * impossible.
453 */
454 if (WARN_ON_ONCE(!oldest))
455 return;
456
457 /* Do not adjust napi->gro_hash[].count, caller is adding a new
458 * SKB to the chain.
459 */
460 skb_list_del_init(oldest);
461 napi_gro_complete(napi, oldest);
462 }
463
dev_gro_receive(struct napi_struct * napi,struct sk_buff * skb)464 static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
465 {
466 u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1);
467 struct gro_list *gro_list = &napi->gro_hash[bucket];
468 struct list_head *head = &net_hotdata.offload_base;
469 struct packet_offload *ptype;
470 __be16 type = skb->protocol;
471 struct sk_buff *pp = NULL;
472 enum gro_result ret;
473 int same_flow;
474
475 if (netif_elide_gro(skb->dev))
476 goto normal;
477
478 gro_list_prepare(&gro_list->list, skb);
479
480 rcu_read_lock();
481 list_for_each_entry_rcu(ptype, head, list) {
482 if (ptype->type == type && ptype->callbacks.gro_receive)
483 goto found_ptype;
484 }
485 rcu_read_unlock();
486 goto normal;
487
488 found_ptype:
489 skb_set_network_header(skb, skb_gro_offset(skb));
490 skb_reset_mac_len(skb);
491 BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32));
492 BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
493 sizeof(u32))); /* Avoid slow unaligned acc */
494 *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
495 NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
496 NAPI_GRO_CB(skb)->count = 1;
497 if (unlikely(skb_is_gso(skb))) {
498 NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
499 /* Only support TCP and non DODGY users. */
500 if (!skb_is_gso_tcp(skb) ||
501 (skb_shinfo(skb)->gso_type & SKB_GSO_DODGY))
502 NAPI_GRO_CB(skb)->flush = 1;
503 }
504
505 /* Setup for GRO checksum validation */
506 switch (skb->ip_summed) {
507 case CHECKSUM_COMPLETE:
508 NAPI_GRO_CB(skb)->csum = skb->csum;
509 NAPI_GRO_CB(skb)->csum_valid = 1;
510 break;
511 case CHECKSUM_UNNECESSARY:
512 NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
513 break;
514 }
515
516 pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
517 ipv6_gro_receive, inet_gro_receive,
518 &gro_list->list, skb);
519
520 rcu_read_unlock();
521
522 if (PTR_ERR(pp) == -EINPROGRESS) {
523 ret = GRO_CONSUMED;
524 goto ok;
525 }
526
527 same_flow = NAPI_GRO_CB(skb)->same_flow;
528 ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED;
529
530 if (pp) {
531 skb_list_del_init(pp);
532 napi_gro_complete(napi, pp);
533 gro_list->count--;
534 }
535
536 if (same_flow)
537 goto ok;
538
539 if (NAPI_GRO_CB(skb)->flush)
540 goto normal;
541
542 if (unlikely(gro_list->count >= MAX_GRO_SKBS))
543 gro_flush_oldest(napi, &gro_list->list);
544 else
545 gro_list->count++;
546
547 /* Must be called before setting NAPI_GRO_CB(skb)->{age|last} */
548 gro_try_pull_from_frag0(skb);
549 NAPI_GRO_CB(skb)->age = jiffies;
550 NAPI_GRO_CB(skb)->last = skb;
551 if (!skb_is_gso(skb))
552 skb_shinfo(skb)->gso_size = skb_gro_len(skb);
553 list_add(&skb->list, &gro_list->list);
554 ret = GRO_HELD;
555 ok:
556 if (gro_list->count) {
557 if (!test_bit(bucket, &napi->gro_bitmask))
558 __set_bit(bucket, &napi->gro_bitmask);
559 } else if (test_bit(bucket, &napi->gro_bitmask)) {
560 __clear_bit(bucket, &napi->gro_bitmask);
561 }
562
563 return ret;
564
565 normal:
566 ret = GRO_NORMAL;
567 gro_try_pull_from_frag0(skb);
568 goto ok;
569 }
570
gro_find_receive_by_type(__be16 type)571 struct packet_offload *gro_find_receive_by_type(__be16 type)
572 {
573 struct list_head *offload_head = &net_hotdata.offload_base;
574 struct packet_offload *ptype;
575
576 list_for_each_entry_rcu(ptype, offload_head, list) {
577 if (ptype->type != type || !ptype->callbacks.gro_receive)
578 continue;
579 return ptype;
580 }
581 return NULL;
582 }
583 EXPORT_SYMBOL(gro_find_receive_by_type);
584
gro_find_complete_by_type(__be16 type)585 struct packet_offload *gro_find_complete_by_type(__be16 type)
586 {
587 struct list_head *offload_head = &net_hotdata.offload_base;
588 struct packet_offload *ptype;
589
590 list_for_each_entry_rcu(ptype, offload_head, list) {
591 if (ptype->type != type || !ptype->callbacks.gro_complete)
592 continue;
593 return ptype;
594 }
595 return NULL;
596 }
597 EXPORT_SYMBOL(gro_find_complete_by_type);
598
napi_skb_finish(struct napi_struct * napi,struct sk_buff * skb,gro_result_t ret)599 static gro_result_t napi_skb_finish(struct napi_struct *napi,
600 struct sk_buff *skb,
601 gro_result_t ret)
602 {
603 switch (ret) {
604 case GRO_NORMAL:
605 gro_normal_one(napi, skb, 1);
606 break;
607
608 case GRO_MERGED_FREE:
609 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
610 napi_skb_free_stolen_head(skb);
611 else if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
612 __kfree_skb(skb);
613 else
614 __napi_kfree_skb(skb, SKB_CONSUMED);
615 break;
616
617 case GRO_HELD:
618 case GRO_MERGED:
619 case GRO_CONSUMED:
620 break;
621 }
622
623 return ret;
624 }
625
napi_gro_receive(struct napi_struct * napi,struct sk_buff * skb)626 gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
627 {
628 gro_result_t ret;
629
630 skb_mark_napi_id(skb, napi);
631 trace_napi_gro_receive_entry(skb);
632
633 skb_gro_reset_offset(skb, 0);
634
635 ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb));
636 trace_napi_gro_receive_exit(ret);
637
638 return ret;
639 }
640 EXPORT_SYMBOL(napi_gro_receive);
641
napi_reuse_skb(struct napi_struct * napi,struct sk_buff * skb)642 static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
643 {
644 if (unlikely(skb->pfmemalloc)) {
645 consume_skb(skb);
646 return;
647 }
648 __skb_pull(skb, skb_headlen(skb));
649 /* restore the reserve we had after netdev_alloc_skb_ip_align() */
650 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb));
651 __vlan_hwaccel_clear_tag(skb);
652 skb->dev = napi->dev;
653 skb->skb_iif = 0;
654
655 /* eth_type_trans() assumes pkt_type is PACKET_HOST */
656 skb->pkt_type = PACKET_HOST;
657
658 skb->encapsulation = 0;
659 skb_shinfo(skb)->gso_type = 0;
660 skb_shinfo(skb)->gso_size = 0;
661 if (unlikely(skb->slow_gro)) {
662 skb_orphan(skb);
663 skb_ext_reset(skb);
664 nf_reset_ct(skb);
665 skb->slow_gro = 0;
666 }
667
668 napi->skb = skb;
669 }
670
napi_get_frags(struct napi_struct * napi)671 struct sk_buff *napi_get_frags(struct napi_struct *napi)
672 {
673 struct sk_buff *skb = napi->skb;
674
675 if (!skb) {
676 skb = napi_alloc_skb(napi, GRO_MAX_HEAD);
677 if (skb) {
678 napi->skb = skb;
679 skb_mark_napi_id(skb, napi);
680 }
681 }
682 return skb;
683 }
684 EXPORT_SYMBOL(napi_get_frags);
685
napi_frags_finish(struct napi_struct * napi,struct sk_buff * skb,gro_result_t ret)686 static gro_result_t napi_frags_finish(struct napi_struct *napi,
687 struct sk_buff *skb,
688 gro_result_t ret)
689 {
690 switch (ret) {
691 case GRO_NORMAL:
692 case GRO_HELD:
693 __skb_push(skb, ETH_HLEN);
694 skb->protocol = eth_type_trans(skb, skb->dev);
695 if (ret == GRO_NORMAL)
696 gro_normal_one(napi, skb, 1);
697 break;
698
699 case GRO_MERGED_FREE:
700 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
701 napi_skb_free_stolen_head(skb);
702 else
703 napi_reuse_skb(napi, skb);
704 break;
705
706 case GRO_MERGED:
707 case GRO_CONSUMED:
708 break;
709 }
710
711 return ret;
712 }
713
714 /* Upper GRO stack assumes network header starts at gro_offset=0
715 * Drivers could call both napi_gro_frags() and napi_gro_receive()
716 * We copy ethernet header into skb->data to have a common layout.
717 */
napi_frags_skb(struct napi_struct * napi)718 static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
719 {
720 struct sk_buff *skb = napi->skb;
721 const struct ethhdr *eth;
722 unsigned int hlen = sizeof(*eth);
723
724 napi->skb = NULL;
725
726 skb_reset_mac_header(skb);
727 skb_gro_reset_offset(skb, hlen);
728
729 if (unlikely(!skb_gro_may_pull(skb, hlen))) {
730 eth = skb_gro_header_slow(skb, hlen, 0);
731 if (unlikely(!eth)) {
732 net_warn_ratelimited("%s: dropping impossible skb from %s\n",
733 __func__, napi->dev->name);
734 napi_reuse_skb(napi, skb);
735 return NULL;
736 }
737 } else {
738 eth = (const struct ethhdr *)skb->data;
739
740 if (NAPI_GRO_CB(skb)->frag0 != skb->data)
741 gro_pull_from_frag0(skb, hlen);
742
743 NAPI_GRO_CB(skb)->frag0 += hlen;
744 NAPI_GRO_CB(skb)->frag0_len -= hlen;
745 }
746 __skb_pull(skb, hlen);
747
748 /*
749 * This works because the only protocols we care about don't require
750 * special handling.
751 * We'll fix it up properly in napi_frags_finish()
752 */
753 skb->protocol = eth->h_proto;
754
755 return skb;
756 }
757
napi_gro_frags(struct napi_struct * napi)758 gro_result_t napi_gro_frags(struct napi_struct *napi)
759 {
760 gro_result_t ret;
761 struct sk_buff *skb = napi_frags_skb(napi);
762
763 trace_napi_gro_frags_entry(skb);
764
765 ret = napi_frags_finish(napi, skb, dev_gro_receive(napi, skb));
766 trace_napi_gro_frags_exit(ret);
767
768 return ret;
769 }
770 EXPORT_SYMBOL(napi_gro_frags);
771
772 /* Compute the checksum from gro_offset and return the folded value
773 * after adding in any pseudo checksum.
774 */
__skb_gro_checksum_complete(struct sk_buff * skb)775 __sum16 __skb_gro_checksum_complete(struct sk_buff *skb)
776 {
777 __wsum wsum;
778 __sum16 sum;
779
780 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0);
781
782 /* NAPI_GRO_CB(skb)->csum holds pseudo checksum */
783 sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum));
784 /* See comments in __skb_checksum_complete(). */
785 if (likely(!sum)) {
786 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
787 !skb->csum_complete_sw)
788 netdev_rx_csum_fault(skb->dev, skb);
789 }
790
791 NAPI_GRO_CB(skb)->csum = wsum;
792 NAPI_GRO_CB(skb)->csum_valid = 1;
793
794 return sum;
795 }
796 EXPORT_SYMBOL(__skb_gro_checksum_complete);
797