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 int segs; 164 165 /* Do not splice page pool based packets w/ non-page pool 166 * packets. This can result in reference count issues as page 167 * pool pages will not decrement the reference count and will 168 * instead be immediately returned to the pool or have frag 169 * count decremented. 170 */ 171 if (p->pp_recycle != skb->pp_recycle) 172 return -ETOOMANYREFS; 173 174 /* pairs with WRITE_ONCE() in netif_set_gro(_ipv4)_max_size() */ 175 gro_max_size = p->protocol == htons(ETH_P_IPV6) ? 176 READ_ONCE(p->dev->gro_max_size) : 177 READ_ONCE(p->dev->gro_ipv4_max_size); 178 179 if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush)) 180 return -E2BIG; 181 182 if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) { 183 if (NAPI_GRO_CB(skb)->proto != IPPROTO_TCP || 184 (p->protocol == htons(ETH_P_IPV6) && 185 skb_headroom(p) < sizeof(struct hop_jumbo_hdr)) || 186 p->encapsulation) 187 return -E2BIG; 188 } 189 190 segs = NAPI_GRO_CB(skb)->count; 191 lp = NAPI_GRO_CB(p)->last; 192 pinfo = skb_shinfo(lp); 193 194 if (headlen <= offset) { 195 skb_frag_t *frag; 196 skb_frag_t *frag2; 197 int i = skbinfo->nr_frags; 198 int nr_frags = pinfo->nr_frags + i; 199 200 if (nr_frags > MAX_SKB_FRAGS) 201 goto merge; 202 203 offset -= headlen; 204 pinfo->nr_frags = nr_frags; 205 skbinfo->nr_frags = 0; 206 207 frag = pinfo->frags + nr_frags; 208 frag2 = skbinfo->frags + i; 209 do { 210 *--frag = *--frag2; 211 } while (--i); 212 213 skb_frag_off_add(frag, offset); 214 skb_frag_size_sub(frag, offset); 215 216 /* all fragments truesize : remove (head size + sk_buff) */ 217 new_truesize = SKB_TRUESIZE(skb_end_offset(skb)); 218 delta_truesize = skb->truesize - new_truesize; 219 220 skb->truesize = new_truesize; 221 skb->len -= skb->data_len; 222 skb->data_len = 0; 223 224 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE; 225 goto done; 226 } else if (skb->head_frag) { 227 int nr_frags = pinfo->nr_frags; 228 skb_frag_t *frag = pinfo->frags + nr_frags; 229 struct page *page = virt_to_head_page(skb->head); 230 unsigned int first_size = headlen - offset; 231 unsigned int first_offset; 232 233 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) 234 goto merge; 235 236 first_offset = skb->data - 237 (unsigned char *)page_address(page) + 238 offset; 239 240 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; 241 242 skb_frag_fill_page_desc(frag, page, first_offset, first_size); 243 244 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); 245 /* We dont need to clear skbinfo->nr_frags here */ 246 247 new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff)); 248 delta_truesize = skb->truesize - new_truesize; 249 skb->truesize = new_truesize; 250 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; 251 goto done; 252 } 253 254 merge: 255 /* sk owenrship - if any - completely transferred to the aggregated packet */ 256 skb->destructor = NULL; 257 delta_truesize = skb->truesize; 258 if (offset > headlen) { 259 unsigned int eat = offset - headlen; 260 261 skb_frag_off_add(&skbinfo->frags[0], eat); 262 skb_frag_size_sub(&skbinfo->frags[0], eat); 263 skb->data_len -= eat; 264 skb->len -= eat; 265 offset = headlen; 266 } 267 268 __skb_pull(skb, offset); 269 270 if (NAPI_GRO_CB(p)->last == p) 271 skb_shinfo(p)->frag_list = skb; 272 else 273 NAPI_GRO_CB(p)->last->next = skb; 274 NAPI_GRO_CB(p)->last = skb; 275 __skb_header_release(skb); 276 lp = p; 277 278 done: 279 NAPI_GRO_CB(p)->count += segs; 280 p->data_len += len; 281 p->truesize += delta_truesize; 282 p->len += len; 283 if (lp != p) { 284 lp->data_len += len; 285 lp->truesize += delta_truesize; 286 lp->len += len; 287 } 288 NAPI_GRO_CB(skb)->same_flow = 1; 289 return 0; 290 } 291 292 293 static void napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb) 294 { 295 struct packet_offload *ptype; 296 __be16 type = skb->protocol; 297 struct list_head *head = &offload_base; 298 int err = -ENOENT; 299 300 BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb)); 301 302 if (NAPI_GRO_CB(skb)->count == 1) { 303 skb_shinfo(skb)->gso_size = 0; 304 goto out; 305 } 306 307 rcu_read_lock(); 308 list_for_each_entry_rcu(ptype, head, list) { 309 if (ptype->type != type || !ptype->callbacks.gro_complete) 310 continue; 311 312 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete, 313 ipv6_gro_complete, inet_gro_complete, 314 skb, 0); 315 break; 316 } 317 rcu_read_unlock(); 318 319 if (err) { 320 WARN_ON(&ptype->list == head); 321 kfree_skb(skb); 322 return; 323 } 324 325 out: 326 gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count); 327 } 328 329 static void __napi_gro_flush_chain(struct napi_struct *napi, u32 index, 330 bool flush_old) 331 { 332 struct list_head *head = &napi->gro_hash[index].list; 333 struct sk_buff *skb, *p; 334 335 list_for_each_entry_safe_reverse(skb, p, head, list) { 336 if (flush_old && NAPI_GRO_CB(skb)->age == jiffies) 337 return; 338 skb_list_del_init(skb); 339 napi_gro_complete(napi, skb); 340 napi->gro_hash[index].count--; 341 } 342 343 if (!napi->gro_hash[index].count) 344 __clear_bit(index, &napi->gro_bitmask); 345 } 346 347 /* napi->gro_hash[].list contains packets ordered by age. 348 * youngest packets at the head of it. 349 * Complete skbs in reverse order to reduce latencies. 350 */ 351 void napi_gro_flush(struct napi_struct *napi, bool flush_old) 352 { 353 unsigned long bitmask = napi->gro_bitmask; 354 unsigned int i, base = ~0U; 355 356 while ((i = ffs(bitmask)) != 0) { 357 bitmask >>= i; 358 base += i; 359 __napi_gro_flush_chain(napi, base, flush_old); 360 } 361 } 362 EXPORT_SYMBOL(napi_gro_flush); 363 364 static void gro_list_prepare(const struct list_head *head, 365 const struct sk_buff *skb) 366 { 367 unsigned int maclen = skb->dev->hard_header_len; 368 u32 hash = skb_get_hash_raw(skb); 369 struct sk_buff *p; 370 371 list_for_each_entry(p, head, list) { 372 unsigned long diffs; 373 374 NAPI_GRO_CB(p)->flush = 0; 375 376 if (hash != skb_get_hash_raw(p)) { 377 NAPI_GRO_CB(p)->same_flow = 0; 378 continue; 379 } 380 381 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; 382 diffs |= p->vlan_all ^ skb->vlan_all; 383 diffs |= skb_metadata_differs(p, skb); 384 if (maclen == ETH_HLEN) 385 diffs |= compare_ether_header(skb_mac_header(p), 386 skb_mac_header(skb)); 387 else if (!diffs) 388 diffs = memcmp(skb_mac_header(p), 389 skb_mac_header(skb), 390 maclen); 391 392 /* in most common scenarions 'slow_gro' is 0 393 * otherwise we are already on some slower paths 394 * either skip all the infrequent tests altogether or 395 * avoid trying too hard to skip each of them individually 396 */ 397 if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) { 398 #if IS_ENABLED(CONFIG_SKB_EXTENSIONS) && IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 399 struct tc_skb_ext *skb_ext; 400 struct tc_skb_ext *p_ext; 401 #endif 402 403 diffs |= p->sk != skb->sk; 404 diffs |= skb_metadata_dst_cmp(p, skb); 405 diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb); 406 407 #if IS_ENABLED(CONFIG_SKB_EXTENSIONS) && IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 408 skb_ext = skb_ext_find(skb, TC_SKB_EXT); 409 p_ext = skb_ext_find(p, TC_SKB_EXT); 410 411 diffs |= (!!p_ext) ^ (!!skb_ext); 412 if (!diffs && unlikely(skb_ext)) 413 diffs |= p_ext->chain ^ skb_ext->chain; 414 #endif 415 } 416 417 NAPI_GRO_CB(p)->same_flow = !diffs; 418 } 419 } 420 421 static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff) 422 { 423 const struct skb_shared_info *pinfo = skb_shinfo(skb); 424 const skb_frag_t *frag0 = &pinfo->frags[0]; 425 426 NAPI_GRO_CB(skb)->data_offset = 0; 427 NAPI_GRO_CB(skb)->frag0 = NULL; 428 NAPI_GRO_CB(skb)->frag0_len = 0; 429 430 if (!skb_headlen(skb) && pinfo->nr_frags && 431 !PageHighMem(skb_frag_page(frag0)) && 432 (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) { 433 NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); 434 NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, 435 skb_frag_size(frag0), 436 skb->end - skb->tail); 437 } 438 } 439 440 static void gro_pull_from_frag0(struct sk_buff *skb, int grow) 441 { 442 struct skb_shared_info *pinfo = skb_shinfo(skb); 443 444 BUG_ON(skb->end - skb->tail < grow); 445 446 memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow); 447 448 skb->data_len -= grow; 449 skb->tail += grow; 450 451 skb_frag_off_add(&pinfo->frags[0], grow); 452 skb_frag_size_sub(&pinfo->frags[0], grow); 453 454 if (unlikely(!skb_frag_size(&pinfo->frags[0]))) { 455 skb_frag_unref(skb, 0); 456 memmove(pinfo->frags, pinfo->frags + 1, 457 --pinfo->nr_frags * sizeof(pinfo->frags[0])); 458 } 459 } 460 461 static void gro_try_pull_from_frag0(struct sk_buff *skb) 462 { 463 int grow = skb_gro_offset(skb) - skb_headlen(skb); 464 465 if (grow > 0) 466 gro_pull_from_frag0(skb, grow); 467 } 468 469 static void gro_flush_oldest(struct napi_struct *napi, struct list_head *head) 470 { 471 struct sk_buff *oldest; 472 473 oldest = list_last_entry(head, struct sk_buff, list); 474 475 /* We are called with head length >= MAX_GRO_SKBS, so this is 476 * impossible. 477 */ 478 if (WARN_ON_ONCE(!oldest)) 479 return; 480 481 /* Do not adjust napi->gro_hash[].count, caller is adding a new 482 * SKB to the chain. 483 */ 484 skb_list_del_init(oldest); 485 napi_gro_complete(napi, oldest); 486 } 487 488 static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 489 { 490 u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1); 491 struct gro_list *gro_list = &napi->gro_hash[bucket]; 492 struct list_head *head = &offload_base; 493 struct packet_offload *ptype; 494 __be16 type = skb->protocol; 495 struct sk_buff *pp = NULL; 496 enum gro_result ret; 497 int same_flow; 498 499 if (netif_elide_gro(skb->dev)) 500 goto normal; 501 502 gro_list_prepare(&gro_list->list, skb); 503 504 rcu_read_lock(); 505 list_for_each_entry_rcu(ptype, head, list) { 506 if (ptype->type == type && ptype->callbacks.gro_receive) 507 goto found_ptype; 508 } 509 rcu_read_unlock(); 510 goto normal; 511 512 found_ptype: 513 skb_set_network_header(skb, skb_gro_offset(skb)); 514 skb_reset_mac_len(skb); 515 BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32)); 516 BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed), 517 sizeof(u32))); /* Avoid slow unaligned acc */ 518 *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0; 519 NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb); 520 NAPI_GRO_CB(skb)->is_atomic = 1; 521 NAPI_GRO_CB(skb)->count = 1; 522 if (unlikely(skb_is_gso(skb))) { 523 NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs; 524 /* Only support TCP and non DODGY users. */ 525 if (!skb_is_gso_tcp(skb) || 526 (skb_shinfo(skb)->gso_type & SKB_GSO_DODGY)) 527 NAPI_GRO_CB(skb)->flush = 1; 528 } 529 530 /* Setup for GRO checksum validation */ 531 switch (skb->ip_summed) { 532 case CHECKSUM_COMPLETE: 533 NAPI_GRO_CB(skb)->csum = skb->csum; 534 NAPI_GRO_CB(skb)->csum_valid = 1; 535 break; 536 case CHECKSUM_UNNECESSARY: 537 NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1; 538 break; 539 } 540 541 pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive, 542 ipv6_gro_receive, inet_gro_receive, 543 &gro_list->list, skb); 544 545 rcu_read_unlock(); 546 547 if (PTR_ERR(pp) == -EINPROGRESS) { 548 ret = GRO_CONSUMED; 549 goto ok; 550 } 551 552 same_flow = NAPI_GRO_CB(skb)->same_flow; 553 ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED; 554 555 if (pp) { 556 skb_list_del_init(pp); 557 napi_gro_complete(napi, pp); 558 gro_list->count--; 559 } 560 561 if (same_flow) 562 goto ok; 563 564 if (NAPI_GRO_CB(skb)->flush) 565 goto normal; 566 567 if (unlikely(gro_list->count >= MAX_GRO_SKBS)) 568 gro_flush_oldest(napi, &gro_list->list); 569 else 570 gro_list->count++; 571 572 /* Must be called before setting NAPI_GRO_CB(skb)->{age|last} */ 573 gro_try_pull_from_frag0(skb); 574 NAPI_GRO_CB(skb)->age = jiffies; 575 NAPI_GRO_CB(skb)->last = skb; 576 if (!skb_is_gso(skb)) 577 skb_shinfo(skb)->gso_size = skb_gro_len(skb); 578 list_add(&skb->list, &gro_list->list); 579 ret = GRO_HELD; 580 ok: 581 if (gro_list->count) { 582 if (!test_bit(bucket, &napi->gro_bitmask)) 583 __set_bit(bucket, &napi->gro_bitmask); 584 } else if (test_bit(bucket, &napi->gro_bitmask)) { 585 __clear_bit(bucket, &napi->gro_bitmask); 586 } 587 588 return ret; 589 590 normal: 591 ret = GRO_NORMAL; 592 gro_try_pull_from_frag0(skb); 593 goto ok; 594 } 595 596 struct packet_offload *gro_find_receive_by_type(__be16 type) 597 { 598 struct list_head *offload_head = &offload_base; 599 struct packet_offload *ptype; 600 601 list_for_each_entry_rcu(ptype, offload_head, list) { 602 if (ptype->type != type || !ptype->callbacks.gro_receive) 603 continue; 604 return ptype; 605 } 606 return NULL; 607 } 608 EXPORT_SYMBOL(gro_find_receive_by_type); 609 610 struct packet_offload *gro_find_complete_by_type(__be16 type) 611 { 612 struct list_head *offload_head = &offload_base; 613 struct packet_offload *ptype; 614 615 list_for_each_entry_rcu(ptype, offload_head, list) { 616 if (ptype->type != type || !ptype->callbacks.gro_complete) 617 continue; 618 return ptype; 619 } 620 return NULL; 621 } 622 EXPORT_SYMBOL(gro_find_complete_by_type); 623 624 static gro_result_t napi_skb_finish(struct napi_struct *napi, 625 struct sk_buff *skb, 626 gro_result_t ret) 627 { 628 switch (ret) { 629 case GRO_NORMAL: 630 gro_normal_one(napi, skb, 1); 631 break; 632 633 case GRO_MERGED_FREE: 634 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 635 napi_skb_free_stolen_head(skb); 636 else if (skb->fclone != SKB_FCLONE_UNAVAILABLE) 637 __kfree_skb(skb); 638 else 639 __napi_kfree_skb(skb, SKB_CONSUMED); 640 break; 641 642 case GRO_HELD: 643 case GRO_MERGED: 644 case GRO_CONSUMED: 645 break; 646 } 647 648 return ret; 649 } 650 651 gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 652 { 653 gro_result_t ret; 654 655 skb_mark_napi_id(skb, napi); 656 trace_napi_gro_receive_entry(skb); 657 658 skb_gro_reset_offset(skb, 0); 659 660 ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb)); 661 trace_napi_gro_receive_exit(ret); 662 663 return ret; 664 } 665 EXPORT_SYMBOL(napi_gro_receive); 666 667 static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) 668 { 669 if (unlikely(skb->pfmemalloc)) { 670 consume_skb(skb); 671 return; 672 } 673 __skb_pull(skb, skb_headlen(skb)); 674 /* restore the reserve we had after netdev_alloc_skb_ip_align() */ 675 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb)); 676 __vlan_hwaccel_clear_tag(skb); 677 skb->dev = napi->dev; 678 skb->skb_iif = 0; 679 680 /* eth_type_trans() assumes pkt_type is PACKET_HOST */ 681 skb->pkt_type = PACKET_HOST; 682 683 skb->encapsulation = 0; 684 skb_shinfo(skb)->gso_type = 0; 685 skb_shinfo(skb)->gso_size = 0; 686 if (unlikely(skb->slow_gro)) { 687 skb_orphan(skb); 688 skb_ext_reset(skb); 689 nf_reset_ct(skb); 690 skb->slow_gro = 0; 691 } 692 693 napi->skb = skb; 694 } 695 696 struct sk_buff *napi_get_frags(struct napi_struct *napi) 697 { 698 struct sk_buff *skb = napi->skb; 699 700 if (!skb) { 701 skb = napi_alloc_skb(napi, GRO_MAX_HEAD); 702 if (skb) { 703 napi->skb = skb; 704 skb_mark_napi_id(skb, napi); 705 } 706 } 707 return skb; 708 } 709 EXPORT_SYMBOL(napi_get_frags); 710 711 static gro_result_t napi_frags_finish(struct napi_struct *napi, 712 struct sk_buff *skb, 713 gro_result_t ret) 714 { 715 switch (ret) { 716 case GRO_NORMAL: 717 case GRO_HELD: 718 __skb_push(skb, ETH_HLEN); 719 skb->protocol = eth_type_trans(skb, skb->dev); 720 if (ret == GRO_NORMAL) 721 gro_normal_one(napi, skb, 1); 722 break; 723 724 case GRO_MERGED_FREE: 725 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 726 napi_skb_free_stolen_head(skb); 727 else 728 napi_reuse_skb(napi, skb); 729 break; 730 731 case GRO_MERGED: 732 case GRO_CONSUMED: 733 break; 734 } 735 736 return ret; 737 } 738 739 /* Upper GRO stack assumes network header starts at gro_offset=0 740 * Drivers could call both napi_gro_frags() and napi_gro_receive() 741 * We copy ethernet header into skb->data to have a common layout. 742 */ 743 static struct sk_buff *napi_frags_skb(struct napi_struct *napi) 744 { 745 struct sk_buff *skb = napi->skb; 746 const struct ethhdr *eth; 747 unsigned int hlen = sizeof(*eth); 748 749 napi->skb = NULL; 750 751 skb_reset_mac_header(skb); 752 skb_gro_reset_offset(skb, hlen); 753 754 if (unlikely(skb_gro_header_hard(skb, hlen))) { 755 eth = skb_gro_header_slow(skb, hlen, 0); 756 if (unlikely(!eth)) { 757 net_warn_ratelimited("%s: dropping impossible skb from %s\n", 758 __func__, napi->dev->name); 759 napi_reuse_skb(napi, skb); 760 return NULL; 761 } 762 } else { 763 eth = (const struct ethhdr *)skb->data; 764 gro_pull_from_frag0(skb, hlen); 765 NAPI_GRO_CB(skb)->frag0 += hlen; 766 NAPI_GRO_CB(skb)->frag0_len -= hlen; 767 } 768 __skb_pull(skb, hlen); 769 770 /* 771 * This works because the only protocols we care about don't require 772 * special handling. 773 * We'll fix it up properly in napi_frags_finish() 774 */ 775 skb->protocol = eth->h_proto; 776 777 return skb; 778 } 779 780 gro_result_t napi_gro_frags(struct napi_struct *napi) 781 { 782 gro_result_t ret; 783 struct sk_buff *skb = napi_frags_skb(napi); 784 785 trace_napi_gro_frags_entry(skb); 786 787 ret = napi_frags_finish(napi, skb, dev_gro_receive(napi, skb)); 788 trace_napi_gro_frags_exit(ret); 789 790 return ret; 791 } 792 EXPORT_SYMBOL(napi_gro_frags); 793 794 /* Compute the checksum from gro_offset and return the folded value 795 * after adding in any pseudo checksum. 796 */ 797 __sum16 __skb_gro_checksum_complete(struct sk_buff *skb) 798 { 799 __wsum wsum; 800 __sum16 sum; 801 802 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0); 803 804 /* NAPI_GRO_CB(skb)->csum holds pseudo checksum */ 805 sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum)); 806 /* See comments in __skb_checksum_complete(). */ 807 if (likely(!sum)) { 808 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && 809 !skb->csum_complete_sw) 810 netdev_rx_csum_fault(skb->dev, skb); 811 } 812 813 NAPI_GRO_CB(skb)->csum = wsum; 814 NAPI_GRO_CB(skb)->csum_valid = 1; 815 816 return sum; 817 } 818 EXPORT_SYMBOL(__skb_gro_checksum_complete); 819