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_eth_gso_segment - segmentation handler for ethernet protocols. 97 * @skb: buffer to segment 98 * @features: features for the output path (see dev->features) 99 * @type: Ethernet Protocol ID 100 */ 101 struct sk_buff *skb_eth_gso_segment(struct sk_buff *skb, 102 netdev_features_t features, __be16 type) 103 { 104 struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT); 105 struct packet_offload *ptype; 106 107 rcu_read_lock(); 108 list_for_each_entry_rcu(ptype, &offload_base, list) { 109 if (ptype->type == type && ptype->callbacks.gso_segment) { 110 segs = ptype->callbacks.gso_segment(skb, features); 111 break; 112 } 113 } 114 rcu_read_unlock(); 115 116 return segs; 117 } 118 EXPORT_SYMBOL(skb_eth_gso_segment); 119 120 /** 121 * skb_mac_gso_segment - mac layer segmentation handler. 122 * @skb: buffer to segment 123 * @features: features for the output path (see dev->features) 124 */ 125 struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb, 126 netdev_features_t features) 127 { 128 struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT); 129 struct packet_offload *ptype; 130 int vlan_depth = skb->mac_len; 131 __be16 type = skb_network_protocol(skb, &vlan_depth); 132 133 if (unlikely(!type)) 134 return ERR_PTR(-EINVAL); 135 136 __skb_pull(skb, vlan_depth); 137 138 rcu_read_lock(); 139 list_for_each_entry_rcu(ptype, &offload_base, list) { 140 if (ptype->type == type && ptype->callbacks.gso_segment) { 141 segs = ptype->callbacks.gso_segment(skb, features); 142 break; 143 } 144 } 145 rcu_read_unlock(); 146 147 __skb_push(skb, skb->data - skb_mac_header(skb)); 148 149 return segs; 150 } 151 EXPORT_SYMBOL(skb_mac_gso_segment); 152 153 int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) 154 { 155 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb); 156 unsigned int offset = skb_gro_offset(skb); 157 unsigned int headlen = skb_headlen(skb); 158 unsigned int len = skb_gro_len(skb); 159 unsigned int delta_truesize; 160 unsigned int gro_max_size; 161 unsigned int new_truesize; 162 struct sk_buff *lp; 163 164 /* pairs with WRITE_ONCE() in netif_set_gro_max_size() */ 165 gro_max_size = READ_ONCE(p->dev->gro_max_size); 166 167 if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush)) 168 return -E2BIG; 169 170 if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) { 171 if (p->protocol != htons(ETH_P_IPV6) || 172 skb_headroom(p) < sizeof(struct hop_jumbo_hdr) || 173 ipv6_hdr(p)->nexthdr != IPPROTO_TCP || 174 p->encapsulation) 175 return -E2BIG; 176 } 177 178 lp = NAPI_GRO_CB(p)->last; 179 pinfo = skb_shinfo(lp); 180 181 if (headlen <= offset) { 182 skb_frag_t *frag; 183 skb_frag_t *frag2; 184 int i = skbinfo->nr_frags; 185 int nr_frags = pinfo->nr_frags + i; 186 187 if (nr_frags > MAX_SKB_FRAGS) 188 goto merge; 189 190 offset -= headlen; 191 pinfo->nr_frags = nr_frags; 192 skbinfo->nr_frags = 0; 193 194 frag = pinfo->frags + nr_frags; 195 frag2 = skbinfo->frags + i; 196 do { 197 *--frag = *--frag2; 198 } while (--i); 199 200 skb_frag_off_add(frag, offset); 201 skb_frag_size_sub(frag, offset); 202 203 /* all fragments truesize : remove (head size + sk_buff) */ 204 new_truesize = SKB_TRUESIZE(skb_end_offset(skb)); 205 delta_truesize = skb->truesize - new_truesize; 206 207 skb->truesize = new_truesize; 208 skb->len -= skb->data_len; 209 skb->data_len = 0; 210 211 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE; 212 goto done; 213 } else if (skb->head_frag) { 214 int nr_frags = pinfo->nr_frags; 215 skb_frag_t *frag = pinfo->frags + nr_frags; 216 struct page *page = virt_to_head_page(skb->head); 217 unsigned int first_size = headlen - offset; 218 unsigned int first_offset; 219 220 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) 221 goto merge; 222 223 first_offset = skb->data - 224 (unsigned char *)page_address(page) + 225 offset; 226 227 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; 228 229 __skb_frag_set_page(frag, page); 230 skb_frag_off_set(frag, first_offset); 231 skb_frag_size_set(frag, first_size); 232 233 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); 234 /* We dont need to clear skbinfo->nr_frags here */ 235 236 new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff)); 237 delta_truesize = skb->truesize - new_truesize; 238 skb->truesize = new_truesize; 239 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; 240 goto done; 241 } 242 243 merge: 244 /* sk owenrship - if any - completely transferred to the aggregated packet */ 245 skb->destructor = NULL; 246 delta_truesize = skb->truesize; 247 if (offset > headlen) { 248 unsigned int eat = offset - headlen; 249 250 skb_frag_off_add(&skbinfo->frags[0], eat); 251 skb_frag_size_sub(&skbinfo->frags[0], eat); 252 skb->data_len -= eat; 253 skb->len -= eat; 254 offset = headlen; 255 } 256 257 __skb_pull(skb, offset); 258 259 if (NAPI_GRO_CB(p)->last == p) 260 skb_shinfo(p)->frag_list = skb; 261 else 262 NAPI_GRO_CB(p)->last->next = skb; 263 NAPI_GRO_CB(p)->last = skb; 264 __skb_header_release(skb); 265 lp = p; 266 267 done: 268 NAPI_GRO_CB(p)->count++; 269 p->data_len += len; 270 p->truesize += delta_truesize; 271 p->len += len; 272 if (lp != p) { 273 lp->data_len += len; 274 lp->truesize += delta_truesize; 275 lp->len += len; 276 } 277 NAPI_GRO_CB(skb)->same_flow = 1; 278 return 0; 279 } 280 281 282 static void napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb) 283 { 284 struct packet_offload *ptype; 285 __be16 type = skb->protocol; 286 struct list_head *head = &offload_base; 287 int err = -ENOENT; 288 289 BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb)); 290 291 if (NAPI_GRO_CB(skb)->count == 1) { 292 skb_shinfo(skb)->gso_size = 0; 293 goto out; 294 } 295 296 rcu_read_lock(); 297 list_for_each_entry_rcu(ptype, head, list) { 298 if (ptype->type != type || !ptype->callbacks.gro_complete) 299 continue; 300 301 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete, 302 ipv6_gro_complete, inet_gro_complete, 303 skb, 0); 304 break; 305 } 306 rcu_read_unlock(); 307 308 if (err) { 309 WARN_ON(&ptype->list == head); 310 kfree_skb(skb); 311 return; 312 } 313 314 out: 315 gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count); 316 } 317 318 static void __napi_gro_flush_chain(struct napi_struct *napi, u32 index, 319 bool flush_old) 320 { 321 struct list_head *head = &napi->gro_hash[index].list; 322 struct sk_buff *skb, *p; 323 324 list_for_each_entry_safe_reverse(skb, p, head, list) { 325 if (flush_old && NAPI_GRO_CB(skb)->age == jiffies) 326 return; 327 skb_list_del_init(skb); 328 napi_gro_complete(napi, skb); 329 napi->gro_hash[index].count--; 330 } 331 332 if (!napi->gro_hash[index].count) 333 __clear_bit(index, &napi->gro_bitmask); 334 } 335 336 /* napi->gro_hash[].list contains packets ordered by age. 337 * youngest packets at the head of it. 338 * Complete skbs in reverse order to reduce latencies. 339 */ 340 void napi_gro_flush(struct napi_struct *napi, bool flush_old) 341 { 342 unsigned long bitmask = napi->gro_bitmask; 343 unsigned int i, base = ~0U; 344 345 while ((i = ffs(bitmask)) != 0) { 346 bitmask >>= i; 347 base += i; 348 __napi_gro_flush_chain(napi, base, flush_old); 349 } 350 } 351 EXPORT_SYMBOL(napi_gro_flush); 352 353 static void gro_list_prepare(const struct list_head *head, 354 const struct sk_buff *skb) 355 { 356 unsigned int maclen = skb->dev->hard_header_len; 357 u32 hash = skb_get_hash_raw(skb); 358 struct sk_buff *p; 359 360 list_for_each_entry(p, head, list) { 361 unsigned long diffs; 362 363 NAPI_GRO_CB(p)->flush = 0; 364 365 if (hash != skb_get_hash_raw(p)) { 366 NAPI_GRO_CB(p)->same_flow = 0; 367 continue; 368 } 369 370 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; 371 diffs |= skb_vlan_tag_present(p) ^ skb_vlan_tag_present(skb); 372 if (skb_vlan_tag_present(p)) 373 diffs |= skb_vlan_tag_get(p) ^ skb_vlan_tag_get(skb); 374 diffs |= skb_metadata_differs(p, skb); 375 if (maclen == ETH_HLEN) 376 diffs |= compare_ether_header(skb_mac_header(p), 377 skb_mac_header(skb)); 378 else if (!diffs) 379 diffs = memcmp(skb_mac_header(p), 380 skb_mac_header(skb), 381 maclen); 382 383 /* in most common scenarions 'slow_gro' is 0 384 * otherwise we are already on some slower paths 385 * either skip all the infrequent tests altogether or 386 * avoid trying too hard to skip each of them individually 387 */ 388 if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) { 389 #if IS_ENABLED(CONFIG_SKB_EXTENSIONS) && IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 390 struct tc_skb_ext *skb_ext; 391 struct tc_skb_ext *p_ext; 392 #endif 393 394 diffs |= p->sk != skb->sk; 395 diffs |= skb_metadata_dst_cmp(p, skb); 396 diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb); 397 398 #if IS_ENABLED(CONFIG_SKB_EXTENSIONS) && IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 399 skb_ext = skb_ext_find(skb, TC_SKB_EXT); 400 p_ext = skb_ext_find(p, TC_SKB_EXT); 401 402 diffs |= (!!p_ext) ^ (!!skb_ext); 403 if (!diffs && unlikely(skb_ext)) 404 diffs |= p_ext->chain ^ skb_ext->chain; 405 #endif 406 } 407 408 NAPI_GRO_CB(p)->same_flow = !diffs; 409 } 410 } 411 412 static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff) 413 { 414 const struct skb_shared_info *pinfo = skb_shinfo(skb); 415 const skb_frag_t *frag0 = &pinfo->frags[0]; 416 417 NAPI_GRO_CB(skb)->data_offset = 0; 418 NAPI_GRO_CB(skb)->frag0 = NULL; 419 NAPI_GRO_CB(skb)->frag0_len = 0; 420 421 if (!skb_headlen(skb) && pinfo->nr_frags && 422 !PageHighMem(skb_frag_page(frag0)) && 423 (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) { 424 NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); 425 NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, 426 skb_frag_size(frag0), 427 skb->end - skb->tail); 428 } 429 } 430 431 static void gro_pull_from_frag0(struct sk_buff *skb, int grow) 432 { 433 struct skb_shared_info *pinfo = skb_shinfo(skb); 434 435 BUG_ON(skb->end - skb->tail < grow); 436 437 memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow); 438 439 skb->data_len -= grow; 440 skb->tail += grow; 441 442 skb_frag_off_add(&pinfo->frags[0], grow); 443 skb_frag_size_sub(&pinfo->frags[0], grow); 444 445 if (unlikely(!skb_frag_size(&pinfo->frags[0]))) { 446 skb_frag_unref(skb, 0); 447 memmove(pinfo->frags, pinfo->frags + 1, 448 --pinfo->nr_frags * sizeof(pinfo->frags[0])); 449 } 450 } 451 452 static void gro_flush_oldest(struct napi_struct *napi, struct list_head *head) 453 { 454 struct sk_buff *oldest; 455 456 oldest = list_last_entry(head, struct sk_buff, list); 457 458 /* We are called with head length >= MAX_GRO_SKBS, so this is 459 * impossible. 460 */ 461 if (WARN_ON_ONCE(!oldest)) 462 return; 463 464 /* Do not adjust napi->gro_hash[].count, caller is adding a new 465 * SKB to the chain. 466 */ 467 skb_list_del_init(oldest); 468 napi_gro_complete(napi, oldest); 469 } 470 471 static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 472 { 473 u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1); 474 struct gro_list *gro_list = &napi->gro_hash[bucket]; 475 struct list_head *head = &offload_base; 476 struct packet_offload *ptype; 477 __be16 type = skb->protocol; 478 struct sk_buff *pp = NULL; 479 enum gro_result ret; 480 int same_flow; 481 int grow; 482 483 if (netif_elide_gro(skb->dev)) 484 goto normal; 485 486 gro_list_prepare(&gro_list->list, skb); 487 488 rcu_read_lock(); 489 list_for_each_entry_rcu(ptype, head, list) { 490 if (ptype->type != type || !ptype->callbacks.gro_receive) 491 continue; 492 493 skb_set_network_header(skb, skb_gro_offset(skb)); 494 skb_reset_mac_len(skb); 495 BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32)); 496 BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed), 497 sizeof(u32))); /* Avoid slow unaligned acc */ 498 *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0; 499 NAPI_GRO_CB(skb)->flush = skb_is_gso(skb) || skb_has_frag_list(skb); 500 NAPI_GRO_CB(skb)->is_atomic = 1; 501 502 /* Setup for GRO checksum validation */ 503 switch (skb->ip_summed) { 504 case CHECKSUM_COMPLETE: 505 NAPI_GRO_CB(skb)->csum = skb->csum; 506 NAPI_GRO_CB(skb)->csum_valid = 1; 507 break; 508 case CHECKSUM_UNNECESSARY: 509 NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1; 510 break; 511 } 512 513 pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive, 514 ipv6_gro_receive, inet_gro_receive, 515 &gro_list->list, skb); 516 break; 517 } 518 rcu_read_unlock(); 519 520 if (&ptype->list == head) 521 goto normal; 522 523 if (PTR_ERR(pp) == -EINPROGRESS) { 524 ret = GRO_CONSUMED; 525 goto ok; 526 } 527 528 same_flow = NAPI_GRO_CB(skb)->same_flow; 529 ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED; 530 531 if (pp) { 532 skb_list_del_init(pp); 533 napi_gro_complete(napi, pp); 534 gro_list->count--; 535 } 536 537 if (same_flow) 538 goto ok; 539 540 if (NAPI_GRO_CB(skb)->flush) 541 goto normal; 542 543 if (unlikely(gro_list->count >= MAX_GRO_SKBS)) 544 gro_flush_oldest(napi, &gro_list->list); 545 else 546 gro_list->count++; 547 548 NAPI_GRO_CB(skb)->count = 1; 549 NAPI_GRO_CB(skb)->age = jiffies; 550 NAPI_GRO_CB(skb)->last = skb; 551 skb_shinfo(skb)->gso_size = skb_gro_len(skb); 552 list_add(&skb->list, &gro_list->list); 553 ret = GRO_HELD; 554 555 pull: 556 grow = skb_gro_offset(skb) - skb_headlen(skb); 557 if (grow > 0) 558 gro_pull_from_frag0(skb, grow); 559 ok: 560 if (gro_list->count) { 561 if (!test_bit(bucket, &napi->gro_bitmask)) 562 __set_bit(bucket, &napi->gro_bitmask); 563 } else if (test_bit(bucket, &napi->gro_bitmask)) { 564 __clear_bit(bucket, &napi->gro_bitmask); 565 } 566 567 return ret; 568 569 normal: 570 ret = GRO_NORMAL; 571 goto pull; 572 } 573 574 struct packet_offload *gro_find_receive_by_type(__be16 type) 575 { 576 struct list_head *offload_head = &offload_base; 577 struct packet_offload *ptype; 578 579 list_for_each_entry_rcu(ptype, offload_head, list) { 580 if (ptype->type != type || !ptype->callbacks.gro_receive) 581 continue; 582 return ptype; 583 } 584 return NULL; 585 } 586 EXPORT_SYMBOL(gro_find_receive_by_type); 587 588 struct packet_offload *gro_find_complete_by_type(__be16 type) 589 { 590 struct list_head *offload_head = &offload_base; 591 struct packet_offload *ptype; 592 593 list_for_each_entry_rcu(ptype, offload_head, list) { 594 if (ptype->type != type || !ptype->callbacks.gro_complete) 595 continue; 596 return ptype; 597 } 598 return NULL; 599 } 600 EXPORT_SYMBOL(gro_find_complete_by_type); 601 602 static gro_result_t napi_skb_finish(struct napi_struct *napi, 603 struct sk_buff *skb, 604 gro_result_t ret) 605 { 606 switch (ret) { 607 case GRO_NORMAL: 608 gro_normal_one(napi, skb, 1); 609 break; 610 611 case GRO_MERGED_FREE: 612 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 613 napi_skb_free_stolen_head(skb); 614 else if (skb->fclone != SKB_FCLONE_UNAVAILABLE) 615 __kfree_skb(skb); 616 else 617 __kfree_skb_defer(skb); 618 break; 619 620 case GRO_HELD: 621 case GRO_MERGED: 622 case GRO_CONSUMED: 623 break; 624 } 625 626 return ret; 627 } 628 629 gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 630 { 631 gro_result_t ret; 632 633 skb_mark_napi_id(skb, napi); 634 trace_napi_gro_receive_entry(skb); 635 636 skb_gro_reset_offset(skb, 0); 637 638 ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb)); 639 trace_napi_gro_receive_exit(ret); 640 641 return ret; 642 } 643 EXPORT_SYMBOL(napi_gro_receive); 644 645 static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) 646 { 647 if (unlikely(skb->pfmemalloc)) { 648 consume_skb(skb); 649 return; 650 } 651 __skb_pull(skb, skb_headlen(skb)); 652 /* restore the reserve we had after netdev_alloc_skb_ip_align() */ 653 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb)); 654 __vlan_hwaccel_clear_tag(skb); 655 skb->dev = napi->dev; 656 skb->skb_iif = 0; 657 658 /* eth_type_trans() assumes pkt_type is PACKET_HOST */ 659 skb->pkt_type = PACKET_HOST; 660 661 skb->encapsulation = 0; 662 skb_shinfo(skb)->gso_type = 0; 663 if (unlikely(skb->slow_gro)) { 664 skb_orphan(skb); 665 skb_ext_reset(skb); 666 nf_reset_ct(skb); 667 skb->slow_gro = 0; 668 } 669 670 napi->skb = skb; 671 } 672 673 struct sk_buff *napi_get_frags(struct napi_struct *napi) 674 { 675 struct sk_buff *skb = napi->skb; 676 677 if (!skb) { 678 skb = napi_alloc_skb(napi, GRO_MAX_HEAD); 679 if (skb) { 680 napi->skb = skb; 681 skb_mark_napi_id(skb, napi); 682 } 683 } 684 return skb; 685 } 686 EXPORT_SYMBOL(napi_get_frags); 687 688 static gro_result_t napi_frags_finish(struct napi_struct *napi, 689 struct sk_buff *skb, 690 gro_result_t ret) 691 { 692 switch (ret) { 693 case GRO_NORMAL: 694 case GRO_HELD: 695 __skb_push(skb, ETH_HLEN); 696 skb->protocol = eth_type_trans(skb, skb->dev); 697 if (ret == GRO_NORMAL) 698 gro_normal_one(napi, skb, 1); 699 break; 700 701 case GRO_MERGED_FREE: 702 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 703 napi_skb_free_stolen_head(skb); 704 else 705 napi_reuse_skb(napi, skb); 706 break; 707 708 case GRO_MERGED: 709 case GRO_CONSUMED: 710 break; 711 } 712 713 return ret; 714 } 715 716 /* Upper GRO stack assumes network header starts at gro_offset=0 717 * Drivers could call both napi_gro_frags() and napi_gro_receive() 718 * We copy ethernet header into skb->data to have a common layout. 719 */ 720 static struct sk_buff *napi_frags_skb(struct napi_struct *napi) 721 { 722 struct sk_buff *skb = napi->skb; 723 const struct ethhdr *eth; 724 unsigned int hlen = sizeof(*eth); 725 726 napi->skb = NULL; 727 728 skb_reset_mac_header(skb); 729 skb_gro_reset_offset(skb, hlen); 730 731 if (unlikely(skb_gro_header_hard(skb, hlen))) { 732 eth = skb_gro_header_slow(skb, hlen, 0); 733 if (unlikely(!eth)) { 734 net_warn_ratelimited("%s: dropping impossible skb from %s\n", 735 __func__, napi->dev->name); 736 napi_reuse_skb(napi, skb); 737 return NULL; 738 } 739 } else { 740 eth = (const struct ethhdr *)skb->data; 741 gro_pull_from_frag0(skb, hlen); 742 NAPI_GRO_CB(skb)->frag0 += hlen; 743 NAPI_GRO_CB(skb)->frag0_len -= hlen; 744 } 745 __skb_pull(skb, hlen); 746 747 /* 748 * This works because the only protocols we care about don't require 749 * special handling. 750 * We'll fix it up properly in napi_frags_finish() 751 */ 752 skb->protocol = eth->h_proto; 753 754 return skb; 755 } 756 757 gro_result_t napi_gro_frags(struct napi_struct *napi) 758 { 759 gro_result_t ret; 760 struct sk_buff *skb = napi_frags_skb(napi); 761 762 trace_napi_gro_frags_entry(skb); 763 764 ret = napi_frags_finish(napi, skb, dev_gro_receive(napi, skb)); 765 trace_napi_gro_frags_exit(ret); 766 767 return ret; 768 } 769 EXPORT_SYMBOL(napi_gro_frags); 770 771 /* Compute the checksum from gro_offset and return the folded value 772 * after adding in any pseudo checksum. 773 */ 774 __sum16 __skb_gro_checksum_complete(struct sk_buff *skb) 775 { 776 __wsum wsum; 777 __sum16 sum; 778 779 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0); 780 781 /* NAPI_GRO_CB(skb)->csum holds pseudo checksum */ 782 sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum)); 783 /* See comments in __skb_checksum_complete(). */ 784 if (likely(!sum)) { 785 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && 786 !skb->csum_complete_sw) 787 netdev_rx_csum_fault(skb->dev, skb); 788 } 789 790 NAPI_GRO_CB(skb)->csum = wsum; 791 NAPI_GRO_CB(skb)->csum_valid = 1; 792 793 return sum; 794 } 795 EXPORT_SYMBOL(__skb_gro_checksum_complete); 796