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 12static DEFINE_SPINLOCK(offload_lock); 13 14/** 15 * dev_add_offload - register offload handlers 16 * @po: protocol offload declaration 17 * 18 * Add protocol offload handlers to the networking stack. The passed 19 * &proto_offload is linked into kernel lists and may not be freed until 20 * it has been removed from the kernel lists. 21 * 22 * This call does not sleep therefore it can not 23 * guarantee all CPU's that are in middle of receiving packets 24 * will see the new offload handlers (until the next received packet). 25 */ 26void dev_add_offload(struct packet_offload *po) 27{ 28 struct packet_offload *elem; 29 30 spin_lock(&offload_lock); 31 list_for_each_entry(elem, &net_hotdata.offload_base, list) { 32 if (po->priority < elem->priority) 33 break; 34 } 35 list_add_rcu(&po->list, elem->list.prev); 36 spin_unlock(&offload_lock); 37} 38EXPORT_SYMBOL(dev_add_offload); 39 40/** 41 * __dev_remove_offload - remove offload handler 42 * @po: packet offload declaration 43 * 44 * Remove a protocol offload handler that was previously added to the 45 * kernel offload handlers by dev_add_offload(). The passed &offload_type 46 * is removed from the kernel lists and can be freed or reused once this 47 * function returns. 48 * 49 * The packet type might still be in use by receivers 50 * and must not be freed until after all the CPU's have gone 51 * through a quiescent state. 52 */ 53static void __dev_remove_offload(struct packet_offload *po) 54{ 55 struct list_head *head = &net_hotdata.offload_base; 56 struct packet_offload *po1; 57 58 spin_lock(&offload_lock); 59 60 list_for_each_entry(po1, head, list) { 61 if (po == po1) { 62 list_del_rcu(&po->list); 63 goto out; 64 } 65 } 66 67 pr_warn("dev_remove_offload: %p not found\n", po); 68out: 69 spin_unlock(&offload_lock); 70} 71 72/** 73 * dev_remove_offload - remove packet offload handler 74 * @po: packet offload declaration 75 * 76 * Remove a packet offload handler that was previously added to the kernel 77 * offload handlers by dev_add_offload(). The passed &offload_type is 78 * removed from the kernel lists and can be freed or reused once this 79 * function returns. 80 * 81 * This call sleeps to guarantee that no CPU is looking at the packet 82 * type after return. 83 */ 84void dev_remove_offload(struct packet_offload *po) 85{ 86 __dev_remove_offload(po); 87 88 synchronize_net(); 89} 90EXPORT_SYMBOL(dev_remove_offload); 91 92 93int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) 94{ 95 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb); 96 unsigned int offset = skb_gro_offset(skb); 97 unsigned int headlen = skb_headlen(skb); 98 unsigned int len = skb_gro_len(skb); 99 unsigned int delta_truesize; 100 unsigned int gro_max_size; 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 /* pairs with WRITE_ONCE() in netif_set_gro(_ipv4)_max_size() */ 115 gro_max_size = p->protocol == htons(ETH_P_IPV6) ? 116 READ_ONCE(p->dev->gro_max_size) : 117 READ_ONCE(p->dev->gro_ipv4_max_size); 118 119 if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush)) 120 return -E2BIG; 121 122 if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) { 123 if (NAPI_GRO_CB(skb)->proto != IPPROTO_TCP || 124 (p->protocol == htons(ETH_P_IPV6) && 125 skb_headroom(p) < sizeof(struct hop_jumbo_hdr)) || 126 p->encapsulation) 127 return -E2BIG; 128 } 129 130 segs = NAPI_GRO_CB(skb)->count; 131 lp = NAPI_GRO_CB(p)->last; 132 pinfo = skb_shinfo(lp); 133 134 if (headlen <= offset) { 135 skb_frag_t *frag; 136 skb_frag_t *frag2; 137 int i = skbinfo->nr_frags; 138 int nr_frags = pinfo->nr_frags + i; 139 140 if (nr_frags > MAX_SKB_FRAGS) 141 goto merge; 142 143 offset -= headlen; 144 pinfo->nr_frags = nr_frags; 145 skbinfo->nr_frags = 0; 146 147 frag = pinfo->frags + nr_frags; 148 frag2 = skbinfo->frags + i; 149 do { 150 *--frag = *--frag2; 151 } while (--i); 152 153 skb_frag_off_add(frag, offset); 154 skb_frag_size_sub(frag, offset); 155 156 /* all fragments truesize : remove (head size + sk_buff) */ 157 new_truesize = SKB_TRUESIZE(skb_end_offset(skb)); 158 delta_truesize = skb->truesize - new_truesize; 159 160 skb->truesize = new_truesize; 161 skb->len -= skb->data_len; 162 skb->data_len = 0; 163 164 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE; 165 goto done; 166 } else if (skb->head_frag) { 167 int nr_frags = pinfo->nr_frags; 168 skb_frag_t *frag = pinfo->frags + nr_frags; 169 struct page *page = virt_to_head_page(skb->head); 170 unsigned int first_size = headlen - offset; 171 unsigned int first_offset; 172 173 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) 174 goto merge; 175 176 first_offset = skb->data - 177 (unsigned char *)page_address(page) + 178 offset; 179 180 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; 181 182 skb_frag_fill_page_desc(frag, page, first_offset, first_size); 183 184 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); 185 /* We dont need to clear skbinfo->nr_frags here */ 186 187 new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff)); 188 delta_truesize = skb->truesize - new_truesize; 189 skb->truesize = new_truesize; 190 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; 191 goto done; 192 } 193 194merge: 195 /* sk ownership - if any - completely transferred to the aggregated packet */ 196 skb->destructor = NULL; 197 skb->sk = NULL; 198 delta_truesize = skb->truesize; 199 if (offset > headlen) { 200 unsigned int eat = offset - headlen; 201 202 skb_frag_off_add(&skbinfo->frags[0], eat); 203 skb_frag_size_sub(&skbinfo->frags[0], eat); 204 skb->data_len -= eat; 205 skb->len -= eat; 206 offset = headlen; 207 } 208 209 __skb_pull(skb, offset); 210 211 if (NAPI_GRO_CB(p)->last == p) 212 skb_shinfo(p)->frag_list = skb; 213 else 214 NAPI_GRO_CB(p)->last->next = skb; 215 NAPI_GRO_CB(p)->last = skb; 216 __skb_header_release(skb); 217 lp = p; 218 219done: 220 NAPI_GRO_CB(p)->count += segs; 221 p->data_len += len; 222 p->truesize += delta_truesize; 223 p->len += len; 224 if (lp != p) { 225 lp->data_len += len; 226 lp->truesize += delta_truesize; 227 lp->len += len; 228 } 229 NAPI_GRO_CB(skb)->same_flow = 1; 230 return 0; 231} 232 233 234static void napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb) 235{ 236 struct list_head *head = &net_hotdata.offload_base; 237 struct packet_offload *ptype; 238 __be16 type = skb->protocol; 239 int err = -ENOENT; 240 241 BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb)); 242 243 if (NAPI_GRO_CB(skb)->count == 1) { 244 skb_shinfo(skb)->gso_size = 0; 245 goto out; 246 } 247 248 rcu_read_lock(); 249 list_for_each_entry_rcu(ptype, head, list) { 250 if (ptype->type != type || !ptype->callbacks.gro_complete) 251 continue; 252 253 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete, 254 ipv6_gro_complete, inet_gro_complete, 255 skb, 0); 256 break; 257 } 258 rcu_read_unlock(); 259 260 if (err) { 261 WARN_ON(&ptype->list == head); 262 kfree_skb(skb); 263 return; 264 } 265 266out: 267 gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count); 268} 269 270static void __napi_gro_flush_chain(struct napi_struct *napi, u32 index, 271 bool flush_old) 272{ 273 struct list_head *head = &napi->gro_hash[index].list; 274 struct sk_buff *skb, *p; 275 276 list_for_each_entry_safe_reverse(skb, p, head, list) { 277 if (flush_old && NAPI_GRO_CB(skb)->age == jiffies) 278 return; 279 skb_list_del_init(skb); 280 napi_gro_complete(napi, skb); 281 napi->gro_hash[index].count--; 282 } 283 284 if (!napi->gro_hash[index].count) 285 __clear_bit(index, &napi->gro_bitmask); 286} 287 288/* napi->gro_hash[].list contains packets ordered by age. 289 * youngest packets at the head of it. 290 * Complete skbs in reverse order to reduce latencies. 291 */ 292void napi_gro_flush(struct napi_struct *napi, bool flush_old) 293{ 294 unsigned long bitmask = napi->gro_bitmask; 295 unsigned int i, base = ~0U; 296 297 while ((i = ffs(bitmask)) != 0) { 298 bitmask >>= i; 299 base += i; 300 __napi_gro_flush_chain(napi, base, flush_old); 301 } 302} 303EXPORT_SYMBOL(napi_gro_flush); 304 305static unsigned long gro_list_prepare_tc_ext(const struct sk_buff *skb, 306 const struct sk_buff *p, 307 unsigned long diffs) 308{ 309#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 310 struct tc_skb_ext *skb_ext; 311 struct tc_skb_ext *p_ext; 312 313 skb_ext = skb_ext_find(skb, TC_SKB_EXT); 314 p_ext = skb_ext_find(p, TC_SKB_EXT); 315 316 diffs |= (!!p_ext) ^ (!!skb_ext); 317 if (!diffs && unlikely(skb_ext)) 318 diffs |= p_ext->chain ^ skb_ext->chain; 319#endif 320 return diffs; 321} 322 323static void gro_list_prepare(const struct list_head *head, 324 const struct sk_buff *skb) 325{ 326 unsigned int maclen = skb->dev->hard_header_len; 327 u32 hash = skb_get_hash_raw(skb); 328 struct sk_buff *p; 329 330 list_for_each_entry(p, head, list) { 331 unsigned long diffs; 332 333 NAPI_GRO_CB(p)->flush = 0; 334 335 if (hash != skb_get_hash_raw(p)) { 336 NAPI_GRO_CB(p)->same_flow = 0; 337 continue; 338 } 339 340 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; 341 diffs |= p->vlan_all ^ skb->vlan_all; 342 diffs |= skb_metadata_differs(p, skb); 343 if (maclen == ETH_HLEN) 344 diffs |= compare_ether_header(skb_mac_header(p), 345 skb_mac_header(skb)); 346 else if (!diffs) 347 diffs = memcmp(skb_mac_header(p), 348 skb_mac_header(skb), 349 maclen); 350 351 /* in most common scenarions 'slow_gro' is 0 352 * otherwise we are already on some slower paths 353 * either skip all the infrequent tests altogether or 354 * avoid trying too hard to skip each of them individually 355 */ 356 if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) { 357 diffs |= p->sk != skb->sk; 358 diffs |= skb_metadata_dst_cmp(p, skb); 359 diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb); 360 361 diffs |= gro_list_prepare_tc_ext(skb, p, diffs); 362 } 363 364 NAPI_GRO_CB(p)->same_flow = !diffs; 365 } 366} 367 368static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff) 369{ 370 const struct skb_shared_info *pinfo; 371 const skb_frag_t *frag0; 372 unsigned int headlen; 373 374 NAPI_GRO_CB(skb)->data_offset = 0; 375 headlen = skb_headlen(skb); 376 NAPI_GRO_CB(skb)->frag0 = skb->data; 377 NAPI_GRO_CB(skb)->frag0_len = headlen; 378 if (headlen) 379 return; 380 381 pinfo = skb_shinfo(skb); 382 frag0 = &pinfo->frags[0]; 383 384 if (pinfo->nr_frags && !PageHighMem(skb_frag_page(frag0)) && 385 (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) { 386 NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); 387 NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, 388 skb_frag_size(frag0), 389 skb->end - skb->tail); 390 } 391} 392 393static void gro_pull_from_frag0(struct sk_buff *skb, int grow) 394{ 395 struct skb_shared_info *pinfo = skb_shinfo(skb); 396 397 BUG_ON(skb->end - skb->tail < grow); 398 399 memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow); 400 401 skb->data_len -= grow; 402 skb->tail += grow; 403 404 skb_frag_off_add(&pinfo->frags[0], grow); 405 skb_frag_size_sub(&pinfo->frags[0], grow); 406 407 if (unlikely(!skb_frag_size(&pinfo->frags[0]))) { 408 skb_frag_unref(skb, 0); 409 memmove(pinfo->frags, pinfo->frags + 1, 410 --pinfo->nr_frags * sizeof(pinfo->frags[0])); 411 } 412} 413 414static void gro_try_pull_from_frag0(struct sk_buff *skb) 415{ 416 int grow = skb_gro_offset(skb) - skb_headlen(skb); 417 418 if (grow > 0) 419 gro_pull_from_frag0(skb, grow); 420} 421 422static void gro_flush_oldest(struct napi_struct *napi, struct list_head *head) 423{ 424 struct sk_buff *oldest; 425 426 oldest = list_last_entry(head, struct sk_buff, list); 427 428 /* We are called with head length >= MAX_GRO_SKBS, so this is 429 * impossible. 430 */ 431 if (WARN_ON_ONCE(!oldest)) 432 return; 433 434 /* Do not adjust napi->gro_hash[].count, caller is adding a new 435 * SKB to the chain. 436 */ 437 skb_list_del_init(oldest); 438 napi_gro_complete(napi, oldest); 439} 440 441static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 442{ 443 u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1); 444 struct gro_list *gro_list = &napi->gro_hash[bucket]; 445 struct list_head *head = &net_hotdata.offload_base; 446 struct packet_offload *ptype; 447 __be16 type = skb->protocol; 448 struct sk_buff *pp = NULL; 449 enum gro_result ret; 450 int same_flow; 451 452 if (netif_elide_gro(skb->dev)) 453 goto normal; 454 455 gro_list_prepare(&gro_list->list, skb); 456 457 rcu_read_lock(); 458 list_for_each_entry_rcu(ptype, head, list) { 459 if (ptype->type == type && ptype->callbacks.gro_receive) 460 goto found_ptype; 461 } 462 rcu_read_unlock(); 463 goto normal; 464 465found_ptype: 466 skb_set_network_header(skb, skb_gro_offset(skb)); 467 skb_reset_mac_len(skb); 468 BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32)); 469 BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed), 470 sizeof(u32))); /* Avoid slow unaligned acc */ 471 *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0; 472 NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb); 473 NAPI_GRO_CB(skb)->is_atomic = 1; 474 NAPI_GRO_CB(skb)->count = 1; 475 if (unlikely(skb_is_gso(skb))) { 476 NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs; 477 /* Only support TCP and non DODGY users. */ 478 if (!skb_is_gso_tcp(skb) || 479 (skb_shinfo(skb)->gso_type & SKB_GSO_DODGY)) 480 NAPI_GRO_CB(skb)->flush = 1; 481 } 482 483 /* Setup for GRO checksum validation */ 484 switch (skb->ip_summed) { 485 case CHECKSUM_COMPLETE: 486 NAPI_GRO_CB(skb)->csum = skb->csum; 487 NAPI_GRO_CB(skb)->csum_valid = 1; 488 break; 489 case CHECKSUM_UNNECESSARY: 490 NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1; 491 break; 492 } 493 494 pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive, 495 ipv6_gro_receive, inet_gro_receive, 496 &gro_list->list, skb); 497 498 rcu_read_unlock(); 499 500 if (PTR_ERR(pp) == -EINPROGRESS) { 501 ret = GRO_CONSUMED; 502 goto ok; 503 } 504 505 same_flow = NAPI_GRO_CB(skb)->same_flow; 506 ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED; 507 508 if (pp) { 509 skb_list_del_init(pp); 510 napi_gro_complete(napi, pp); 511 gro_list->count--; 512 } 513 514 if (same_flow) 515 goto ok; 516 517 if (NAPI_GRO_CB(skb)->flush) 518 goto normal; 519 520 if (unlikely(gro_list->count >= MAX_GRO_SKBS)) 521 gro_flush_oldest(napi, &gro_list->list); 522 else 523 gro_list->count++; 524 525 /* Must be called before setting NAPI_GRO_CB(skb)->{age|last} */ 526 gro_try_pull_from_frag0(skb); 527 NAPI_GRO_CB(skb)->age = jiffies; 528 NAPI_GRO_CB(skb)->last = skb; 529 if (!skb_is_gso(skb)) 530 skb_shinfo(skb)->gso_size = skb_gro_len(skb); 531 list_add(&skb->list, &gro_list->list); 532 ret = GRO_HELD; 533ok: 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 543normal: 544 ret = GRO_NORMAL; 545 gro_try_pull_from_frag0(skb); 546 goto ok; 547} 548 549struct packet_offload *gro_find_receive_by_type(__be16 type) 550{ 551 struct list_head *offload_head = &net_hotdata.offload_base; 552 struct packet_offload *ptype; 553 554 list_for_each_entry_rcu(ptype, offload_head, list) { 555 if (ptype->type != type || !ptype->callbacks.gro_receive) 556 continue; 557 return ptype; 558 } 559 return NULL; 560} 561EXPORT_SYMBOL(gro_find_receive_by_type); 562 563struct packet_offload *gro_find_complete_by_type(__be16 type) 564{ 565 struct list_head *offload_head = &net_hotdata.offload_base; 566 struct packet_offload *ptype; 567 568 list_for_each_entry_rcu(ptype, offload_head, list) { 569 if (ptype->type != type || !ptype->callbacks.gro_complete) 570 continue; 571 return ptype; 572 } 573 return NULL; 574} 575EXPORT_SYMBOL(gro_find_complete_by_type); 576 577static gro_result_t napi_skb_finish(struct napi_struct *napi, 578 struct sk_buff *skb, 579 gro_result_t ret) 580{ 581 switch (ret) { 582 case GRO_NORMAL: 583 gro_normal_one(napi, skb, 1); 584 break; 585 586 case GRO_MERGED_FREE: 587 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 588 napi_skb_free_stolen_head(skb); 589 else if (skb->fclone != SKB_FCLONE_UNAVAILABLE) 590 __kfree_skb(skb); 591 else 592 __napi_kfree_skb(skb, SKB_CONSUMED); 593 break; 594 595 case GRO_HELD: 596 case GRO_MERGED: 597 case GRO_CONSUMED: 598 break; 599 } 600 601 return ret; 602} 603 604gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 605{ 606 gro_result_t ret; 607 608 skb_mark_napi_id(skb, napi); 609 trace_napi_gro_receive_entry(skb); 610 611 skb_gro_reset_offset(skb, 0); 612 613 ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb)); 614 trace_napi_gro_receive_exit(ret); 615 616 return ret; 617} 618EXPORT_SYMBOL(napi_gro_receive); 619 620static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) 621{ 622 if (unlikely(skb->pfmemalloc)) { 623 consume_skb(skb); 624 return; 625 } 626 __skb_pull(skb, skb_headlen(skb)); 627 /* restore the reserve we had after netdev_alloc_skb_ip_align() */ 628 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb)); 629 __vlan_hwaccel_clear_tag(skb); 630 skb->dev = napi->dev; 631 skb->skb_iif = 0; 632 633 /* eth_type_trans() assumes pkt_type is PACKET_HOST */ 634 skb->pkt_type = PACKET_HOST; 635 636 skb->encapsulation = 0; 637 skb_shinfo(skb)->gso_type = 0; 638 skb_shinfo(skb)->gso_size = 0; 639 if (unlikely(skb->slow_gro)) { 640 skb_orphan(skb); 641 skb_ext_reset(skb); 642 nf_reset_ct(skb); 643 skb->slow_gro = 0; 644 } 645 646 napi->skb = skb; 647} 648 649struct sk_buff *napi_get_frags(struct napi_struct *napi) 650{ 651 struct sk_buff *skb = napi->skb; 652 653 if (!skb) { 654 skb = napi_alloc_skb(napi, GRO_MAX_HEAD); 655 if (skb) { 656 napi->skb = skb; 657 skb_mark_napi_id(skb, napi); 658 } 659 } 660 return skb; 661} 662EXPORT_SYMBOL(napi_get_frags); 663 664static gro_result_t napi_frags_finish(struct napi_struct *napi, 665 struct sk_buff *skb, 666 gro_result_t ret) 667{ 668 switch (ret) { 669 case GRO_NORMAL: 670 case GRO_HELD: 671 __skb_push(skb, ETH_HLEN); 672 skb->protocol = eth_type_trans(skb, skb->dev); 673 if (ret == GRO_NORMAL) 674 gro_normal_one(napi, skb, 1); 675 break; 676 677 case GRO_MERGED_FREE: 678 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 679 napi_skb_free_stolen_head(skb); 680 else 681 napi_reuse_skb(napi, skb); 682 break; 683 684 case GRO_MERGED: 685 case GRO_CONSUMED: 686 break; 687 } 688 689 return ret; 690} 691 692/* Upper GRO stack assumes network header starts at gro_offset=0 693 * Drivers could call both napi_gro_frags() and napi_gro_receive() 694 * We copy ethernet header into skb->data to have a common layout. 695 */ 696static struct sk_buff *napi_frags_skb(struct napi_struct *napi) 697{ 698 struct sk_buff *skb = napi->skb; 699 const struct ethhdr *eth; 700 unsigned int hlen = sizeof(*eth); 701 702 napi->skb = NULL; 703 704 skb_reset_mac_header(skb); 705 skb_gro_reset_offset(skb, hlen); 706 707 if (unlikely(!skb_gro_may_pull(skb, hlen))) { 708 eth = skb_gro_header_slow(skb, hlen, 0); 709 if (unlikely(!eth)) { 710 net_warn_ratelimited("%s: dropping impossible skb from %s\n", 711 __func__, napi->dev->name); 712 napi_reuse_skb(napi, skb); 713 return NULL; 714 } 715 } else { 716 eth = (const struct ethhdr *)skb->data; 717 718 if (NAPI_GRO_CB(skb)->frag0 != skb->data) 719 gro_pull_from_frag0(skb, hlen); 720 721 NAPI_GRO_CB(skb)->frag0 += hlen; 722 NAPI_GRO_CB(skb)->frag0_len -= hlen; 723 } 724 __skb_pull(skb, hlen); 725 726 /* 727 * This works because the only protocols we care about don't require 728 * special handling. 729 * We'll fix it up properly in napi_frags_finish() 730 */ 731 skb->protocol = eth->h_proto; 732 733 return skb; 734} 735 736gro_result_t napi_gro_frags(struct napi_struct *napi) 737{ 738 gro_result_t ret; 739 struct sk_buff *skb = napi_frags_skb(napi); 740 741 trace_napi_gro_frags_entry(skb); 742 743 ret = napi_frags_finish(napi, skb, dev_gro_receive(napi, skb)); 744 trace_napi_gro_frags_exit(ret); 745 746 return ret; 747} 748EXPORT_SYMBOL(napi_gro_frags); 749 750/* Compute the checksum from gro_offset and return the folded value 751 * after adding in any pseudo checksum. 752 */ 753__sum16 __skb_gro_checksum_complete(struct sk_buff *skb) 754{ 755 __wsum wsum; 756 __sum16 sum; 757 758 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0); 759 760 /* NAPI_GRO_CB(skb)->csum holds pseudo checksum */ 761 sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum)); 762 /* See comments in __skb_checksum_complete(). */ 763 if (likely(!sum)) { 764 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && 765 !skb->csum_complete_sw) 766 netdev_rx_csum_fault(skb->dev, skb); 767 } 768 769 NAPI_GRO_CB(skb)->csum = wsum; 770 NAPI_GRO_CB(skb)->csum_valid = 1; 771 772 return sum; 773} 774EXPORT_SYMBOL(__skb_gro_checksum_complete); 775