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