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 static DEFINE_SPINLOCK(offload_lock); 11 12 /** 13 * dev_add_offload - register offload handlers 14 * @po: protocol offload declaration 15 * 16 * Add protocol offload handlers to the networking stack. The passed 17 * &proto_offload is linked into kernel lists and may not be freed until 18 * it has been removed from the kernel lists. 19 * 20 * This call does not sleep therefore it can not 21 * guarantee all CPU's that are in middle of receiving packets 22 * will see the new offload handlers (until the next received packet). 23 */ 24 void dev_add_offload(struct packet_offload *po) 25 { 26 struct packet_offload *elem; 27 28 spin_lock(&offload_lock); 29 list_for_each_entry(elem, &net_hotdata.offload_base, list) { 30 if (po->priority < elem->priority) 31 break; 32 } 33 list_add_rcu(&po->list, elem->list.prev); 34 spin_unlock(&offload_lock); 35 } 36 EXPORT_SYMBOL(dev_add_offload); 37 38 /** 39 * __dev_remove_offload - remove offload handler 40 * @po: packet offload declaration 41 * 42 * Remove a protocol offload handler that was previously added to the 43 * kernel offload handlers by dev_add_offload(). The passed &offload_type 44 * is removed from the kernel lists and can be freed or reused once this 45 * function returns. 46 * 47 * The packet type might still be in use by receivers 48 * and must not be freed until after all the CPU's have gone 49 * through a quiescent state. 50 */ 51 static void __dev_remove_offload(struct packet_offload *po) 52 { 53 struct list_head *head = &net_hotdata.offload_base; 54 struct packet_offload *po1; 55 56 spin_lock(&offload_lock); 57 58 list_for_each_entry(po1, head, list) { 59 if (po == po1) { 60 list_del_rcu(&po->list); 61 goto out; 62 } 63 } 64 65 pr_warn("dev_remove_offload: %p not found\n", po); 66 out: 67 spin_unlock(&offload_lock); 68 } 69 70 /** 71 * dev_remove_offload - remove packet offload handler 72 * @po: packet offload declaration 73 * 74 * Remove a packet offload handler that was previously added to the kernel 75 * offload handlers by dev_add_offload(). The passed &offload_type is 76 * removed from the kernel lists and can be freed or reused once this 77 * function returns. 78 * 79 * This call sleeps to guarantee that no CPU is looking at the packet 80 * type after return. 81 */ 82 void dev_remove_offload(struct packet_offload *po) 83 { 84 __dev_remove_offload(po); 85 86 synchronize_net(); 87 } 88 EXPORT_SYMBOL(dev_remove_offload); 89 90 91 int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) 92 { 93 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb); 94 unsigned int offset = skb_gro_offset(skb); 95 unsigned int headlen = skb_headlen(skb); 96 unsigned int len = skb_gro_len(skb); 97 unsigned int delta_truesize; 98 unsigned int new_truesize; 99 struct sk_buff *lp; 100 int segs; 101 102 /* Do not splice page pool based packets w/ non-page pool 103 * packets. This can result in reference count issues as page 104 * pool pages will not decrement the reference count and will 105 * instead be immediately returned to the pool or have frag 106 * count decremented. 107 */ 108 if (p->pp_recycle != skb->pp_recycle) 109 return -ETOOMANYREFS; 110 111 if (unlikely(p->len + len >= netif_get_gro_max_size(p->dev, p) || 112 NAPI_GRO_CB(skb)->flush)) 113 return -E2BIG; 114 115 if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) { 116 if (NAPI_GRO_CB(skb)->proto != IPPROTO_TCP || 117 (p->protocol == htons(ETH_P_IPV6) && 118 skb_headroom(p) < sizeof(struct hop_jumbo_hdr)) || 119 p->encapsulation) 120 return -E2BIG; 121 } 122 123 segs = NAPI_GRO_CB(skb)->count; 124 lp = NAPI_GRO_CB(p)->last; 125 pinfo = skb_shinfo(lp); 126 127 if (headlen <= offset) { 128 skb_frag_t *frag; 129 skb_frag_t *frag2; 130 int i = skbinfo->nr_frags; 131 int nr_frags = pinfo->nr_frags + i; 132 133 if (nr_frags > MAX_SKB_FRAGS) 134 goto merge; 135 136 offset -= headlen; 137 pinfo->nr_frags = nr_frags; 138 skbinfo->nr_frags = 0; 139 140 frag = pinfo->frags + nr_frags; 141 frag2 = skbinfo->frags + i; 142 do { 143 *--frag = *--frag2; 144 } while (--i); 145 146 skb_frag_off_add(frag, offset); 147 skb_frag_size_sub(frag, offset); 148 149 /* all fragments truesize : remove (head size + sk_buff) */ 150 new_truesize = SKB_TRUESIZE(skb_end_offset(skb)); 151 delta_truesize = skb->truesize - new_truesize; 152 153 skb->truesize = new_truesize; 154 skb->len -= skb->data_len; 155 skb->data_len = 0; 156 157 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE; 158 goto done; 159 } else if (skb->head_frag) { 160 int nr_frags = pinfo->nr_frags; 161 skb_frag_t *frag = pinfo->frags + nr_frags; 162 struct page *page = virt_to_head_page(skb->head); 163 unsigned int first_size = headlen - offset; 164 unsigned int first_offset; 165 166 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) 167 goto merge; 168 169 first_offset = skb->data - 170 (unsigned char *)page_address(page) + 171 offset; 172 173 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; 174 175 skb_frag_fill_page_desc(frag, page, first_offset, first_size); 176 177 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); 178 /* We dont need to clear skbinfo->nr_frags here */ 179 180 new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff)); 181 delta_truesize = skb->truesize - new_truesize; 182 skb->truesize = new_truesize; 183 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; 184 goto done; 185 } 186 187 merge: 188 /* sk ownership - if any - completely transferred to the aggregated packet */ 189 skb->destructor = NULL; 190 skb->sk = NULL; 191 delta_truesize = skb->truesize; 192 if (offset > headlen) { 193 unsigned int eat = offset - headlen; 194 195 skb_frag_off_add(&skbinfo->frags[0], eat); 196 skb_frag_size_sub(&skbinfo->frags[0], eat); 197 skb->data_len -= eat; 198 skb->len -= eat; 199 offset = headlen; 200 } 201 202 __skb_pull(skb, offset); 203 204 if (NAPI_GRO_CB(p)->last == p) 205 skb_shinfo(p)->frag_list = skb; 206 else 207 NAPI_GRO_CB(p)->last->next = skb; 208 NAPI_GRO_CB(p)->last = skb; 209 __skb_header_release(skb); 210 lp = p; 211 212 done: 213 NAPI_GRO_CB(p)->count += segs; 214 p->data_len += len; 215 p->truesize += delta_truesize; 216 p->len += len; 217 if (lp != p) { 218 lp->data_len += len; 219 lp->truesize += delta_truesize; 220 lp->len += len; 221 } 222 NAPI_GRO_CB(skb)->same_flow = 1; 223 return 0; 224 } 225 226 int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb) 227 { 228 if (unlikely(p->len + skb->len >= 65536)) 229 return -E2BIG; 230 231 if (NAPI_GRO_CB(p)->last == p) 232 skb_shinfo(p)->frag_list = skb; 233 else 234 NAPI_GRO_CB(p)->last->next = skb; 235 236 skb_pull(skb, skb_gro_offset(skb)); 237 238 NAPI_GRO_CB(p)->last = skb; 239 NAPI_GRO_CB(p)->count++; 240 p->data_len += skb->len; 241 242 /* sk ownership - if any - completely transferred to the aggregated packet */ 243 skb->destructor = NULL; 244 skb->sk = NULL; 245 p->truesize += skb->truesize; 246 p->len += skb->len; 247 248 NAPI_GRO_CB(skb)->same_flow = 1; 249 250 return 0; 251 } 252 253 static void gro_complete(struct gro_node *gro, struct sk_buff *skb) 254 { 255 struct list_head *head = &net_hotdata.offload_base; 256 struct packet_offload *ptype; 257 __be16 type = skb->protocol; 258 int err = -ENOENT; 259 260 BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb)); 261 262 if (NAPI_GRO_CB(skb)->count == 1) { 263 skb_shinfo(skb)->gso_size = 0; 264 goto out; 265 } 266 267 rcu_read_lock(); 268 list_for_each_entry_rcu(ptype, head, list) { 269 if (ptype->type != type || !ptype->callbacks.gro_complete) 270 continue; 271 272 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete, 273 ipv6_gro_complete, inet_gro_complete, 274 skb, 0); 275 break; 276 } 277 rcu_read_unlock(); 278 279 if (err) { 280 WARN_ON(&ptype->list == head); 281 kfree_skb(skb); 282 return; 283 } 284 285 out: 286 gro_normal_one(gro, skb, NAPI_GRO_CB(skb)->count); 287 } 288 289 static void __gro_flush_chain(struct gro_node *gro, u32 index, bool flush_old) 290 { 291 struct list_head *head = &gro->hash[index].list; 292 struct sk_buff *skb, *p; 293 294 list_for_each_entry_safe_reverse(skb, p, head, list) { 295 if (flush_old && NAPI_GRO_CB(skb)->age == jiffies) 296 return; 297 skb_list_del_init(skb); 298 gro_complete(gro, skb); 299 gro->hash[index].count--; 300 } 301 302 if (!gro->hash[index].count) 303 __clear_bit(index, &gro->bitmask); 304 } 305 306 /* 307 * gro->hash[].list contains packets ordered by age. 308 * youngest packets at the head of it. 309 * Complete skbs in reverse order to reduce latencies. 310 */ 311 void __gro_flush(struct gro_node *gro, bool flush_old) 312 { 313 unsigned long bitmask = gro->bitmask; 314 unsigned int i, base = ~0U; 315 316 while ((i = ffs(bitmask)) != 0) { 317 bitmask >>= i; 318 base += i; 319 __gro_flush_chain(gro, base, flush_old); 320 } 321 } 322 EXPORT_SYMBOL(__gro_flush); 323 324 static unsigned long gro_list_prepare_tc_ext(const struct sk_buff *skb, 325 const struct sk_buff *p, 326 unsigned long diffs) 327 { 328 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 329 struct tc_skb_ext *skb_ext; 330 struct tc_skb_ext *p_ext; 331 332 skb_ext = skb_ext_find(skb, TC_SKB_EXT); 333 p_ext = skb_ext_find(p, TC_SKB_EXT); 334 335 diffs |= (!!p_ext) ^ (!!skb_ext); 336 if (!diffs && unlikely(skb_ext)) 337 diffs |= p_ext->chain ^ skb_ext->chain; 338 #endif 339 return diffs; 340 } 341 342 static void gro_list_prepare(const struct list_head *head, 343 const struct sk_buff *skb) 344 { 345 unsigned int maclen = skb->dev->hard_header_len; 346 u32 hash = skb_get_hash_raw(skb); 347 struct sk_buff *p; 348 349 list_for_each_entry(p, head, list) { 350 unsigned long diffs; 351 352 if (hash != skb_get_hash_raw(p)) { 353 NAPI_GRO_CB(p)->same_flow = 0; 354 continue; 355 } 356 357 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; 358 diffs |= p->vlan_all ^ skb->vlan_all; 359 diffs |= skb_metadata_differs(p, skb); 360 if (maclen == ETH_HLEN) 361 diffs |= compare_ether_header(skb_mac_header(p), 362 skb_mac_header(skb)); 363 else if (!diffs) 364 diffs = memcmp(skb_mac_header(p), 365 skb_mac_header(skb), 366 maclen); 367 368 /* in most common scenarios 'slow_gro' is 0 369 * otherwise we are already on some slower paths 370 * either skip all the infrequent tests altogether or 371 * avoid trying too hard to skip each of them individually 372 */ 373 if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) { 374 diffs |= p->sk != skb->sk; 375 diffs |= skb_metadata_dst_cmp(p, skb); 376 diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb); 377 378 diffs |= gro_list_prepare_tc_ext(skb, p, diffs); 379 } 380 381 NAPI_GRO_CB(p)->same_flow = !diffs; 382 } 383 } 384 385 static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff) 386 { 387 const struct skb_shared_info *pinfo; 388 const skb_frag_t *frag0; 389 unsigned int headlen; 390 391 NAPI_GRO_CB(skb)->network_offset = 0; 392 NAPI_GRO_CB(skb)->data_offset = 0; 393 headlen = skb_headlen(skb); 394 NAPI_GRO_CB(skb)->frag0 = skb->data; 395 NAPI_GRO_CB(skb)->frag0_len = headlen; 396 if (headlen) 397 return; 398 399 pinfo = skb_shinfo(skb); 400 frag0 = &pinfo->frags[0]; 401 402 if (pinfo->nr_frags && skb_frag_page(frag0) && 403 !PageHighMem(skb_frag_page(frag0)) && 404 (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) { 405 NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); 406 NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, 407 skb_frag_size(frag0), 408 skb->end - skb->tail); 409 } 410 } 411 412 static void gro_pull_from_frag0(struct sk_buff *skb, int grow) 413 { 414 struct skb_shared_info *pinfo = skb_shinfo(skb); 415 416 BUG_ON(skb->end - skb->tail < grow); 417 418 memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow); 419 420 skb->data_len -= grow; 421 skb->tail += grow; 422 423 skb_frag_off_add(&pinfo->frags[0], grow); 424 skb_frag_size_sub(&pinfo->frags[0], grow); 425 426 if (unlikely(!skb_frag_size(&pinfo->frags[0]))) { 427 skb_frag_unref(skb, 0); 428 memmove(pinfo->frags, pinfo->frags + 1, 429 --pinfo->nr_frags * sizeof(pinfo->frags[0])); 430 } 431 } 432 433 static void gro_try_pull_from_frag0(struct sk_buff *skb) 434 { 435 int grow = skb_gro_offset(skb) - skb_headlen(skb); 436 437 if (grow > 0) 438 gro_pull_from_frag0(skb, grow); 439 } 440 441 static void gro_flush_oldest(struct gro_node *gro, struct list_head *head) 442 { 443 struct sk_buff *oldest; 444 445 oldest = list_last_entry(head, struct sk_buff, list); 446 447 /* We are called with head length >= MAX_GRO_SKBS, so this is 448 * impossible. 449 */ 450 if (WARN_ON_ONCE(!oldest)) 451 return; 452 453 /* Do not adjust napi->gro_hash[].count, caller is adding a new 454 * SKB to the chain. 455 */ 456 skb_list_del_init(oldest); 457 gro_complete(gro, oldest); 458 } 459 460 static enum gro_result dev_gro_receive(struct gro_node *gro, 461 struct sk_buff *skb) 462 { 463 u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1); 464 struct list_head *head = &net_hotdata.offload_base; 465 struct gro_list *gro_list = &gro->hash[bucket]; 466 struct packet_offload *ptype; 467 __be16 type = skb->protocol; 468 struct sk_buff *pp = NULL; 469 enum gro_result ret; 470 int same_flow; 471 472 if (netif_elide_gro(skb->dev)) 473 goto normal; 474 475 gro_list_prepare(&gro_list->list, skb); 476 477 rcu_read_lock(); 478 list_for_each_entry_rcu(ptype, head, list) { 479 if (ptype->type == type && ptype->callbacks.gro_receive) 480 goto found_ptype; 481 } 482 rcu_read_unlock(); 483 goto normal; 484 485 found_ptype: 486 skb_set_network_header(skb, skb_gro_offset(skb)); 487 skb_reset_mac_len(skb); 488 BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32)); 489 BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed), 490 sizeof(u32))); /* Avoid slow unaligned acc */ 491 *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0; 492 NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb); 493 NAPI_GRO_CB(skb)->count = 1; 494 if (unlikely(skb_is_gso(skb))) { 495 NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs; 496 /* Only support TCP and non DODGY users. */ 497 if (!skb_is_gso_tcp(skb) || 498 (skb_shinfo(skb)->gso_type & SKB_GSO_DODGY)) 499 NAPI_GRO_CB(skb)->flush = 1; 500 } 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); 516 517 rcu_read_unlock(); 518 519 if (PTR_ERR(pp) == -EINPROGRESS) { 520 ret = GRO_CONSUMED; 521 goto ok; 522 } 523 524 same_flow = NAPI_GRO_CB(skb)->same_flow; 525 ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED; 526 527 if (pp) { 528 skb_list_del_init(pp); 529 gro_complete(gro, pp); 530 gro_list->count--; 531 } 532 533 if (same_flow) 534 goto ok; 535 536 if (NAPI_GRO_CB(skb)->flush) 537 goto normal; 538 539 if (unlikely(gro_list->count >= MAX_GRO_SKBS)) 540 gro_flush_oldest(gro, &gro_list->list); 541 else 542 gro_list->count++; 543 544 /* Must be called before setting NAPI_GRO_CB(skb)->{age|last} */ 545 gro_try_pull_from_frag0(skb); 546 NAPI_GRO_CB(skb)->age = jiffies; 547 NAPI_GRO_CB(skb)->last = skb; 548 if (!skb_is_gso(skb)) 549 skb_shinfo(skb)->gso_size = skb_gro_len(skb); 550 list_add(&skb->list, &gro_list->list); 551 ret = GRO_HELD; 552 ok: 553 if (gro_list->count) { 554 if (!test_bit(bucket, &gro->bitmask)) 555 __set_bit(bucket, &gro->bitmask); 556 } else if (test_bit(bucket, &gro->bitmask)) { 557 __clear_bit(bucket, &gro->bitmask); 558 } 559 560 return ret; 561 562 normal: 563 ret = GRO_NORMAL; 564 gro_try_pull_from_frag0(skb); 565 goto ok; 566 } 567 568 struct packet_offload *gro_find_receive_by_type(__be16 type) 569 { 570 struct list_head *offload_head = &net_hotdata.offload_base; 571 struct packet_offload *ptype; 572 573 list_for_each_entry_rcu(ptype, offload_head, list) { 574 if (ptype->type != type || !ptype->callbacks.gro_receive) 575 continue; 576 return ptype; 577 } 578 return NULL; 579 } 580 EXPORT_SYMBOL(gro_find_receive_by_type); 581 582 struct packet_offload *gro_find_complete_by_type(__be16 type) 583 { 584 struct list_head *offload_head = &net_hotdata.offload_base; 585 struct packet_offload *ptype; 586 587 list_for_each_entry_rcu(ptype, offload_head, list) { 588 if (ptype->type != type || !ptype->callbacks.gro_complete) 589 continue; 590 return ptype; 591 } 592 return NULL; 593 } 594 EXPORT_SYMBOL(gro_find_complete_by_type); 595 596 static gro_result_t gro_skb_finish(struct gro_node *gro, struct sk_buff *skb, 597 gro_result_t ret) 598 { 599 switch (ret) { 600 case GRO_NORMAL: 601 gro_normal_one(gro, skb, 1); 602 break; 603 604 case GRO_MERGED_FREE: 605 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 606 napi_skb_free_stolen_head(skb); 607 else if (skb->fclone != SKB_FCLONE_UNAVAILABLE) 608 __kfree_skb(skb); 609 else 610 __napi_kfree_skb(skb, SKB_CONSUMED); 611 break; 612 613 case GRO_HELD: 614 case GRO_MERGED: 615 case GRO_CONSUMED: 616 break; 617 } 618 619 return ret; 620 } 621 622 gro_result_t gro_receive_skb(struct gro_node *gro, struct sk_buff *skb) 623 { 624 gro_result_t ret; 625 626 __skb_mark_napi_id(skb, gro); 627 trace_napi_gro_receive_entry(skb); 628 629 skb_gro_reset_offset(skb, 0); 630 631 ret = gro_skb_finish(gro, skb, dev_gro_receive(gro, skb)); 632 trace_napi_gro_receive_exit(ret); 633 634 return ret; 635 } 636 EXPORT_SYMBOL(gro_receive_skb); 637 638 static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) 639 { 640 if (unlikely(skb->pfmemalloc)) { 641 consume_skb(skb); 642 return; 643 } 644 __skb_pull(skb, skb_headlen(skb)); 645 /* restore the reserve we had after netdev_alloc_skb_ip_align() */ 646 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb)); 647 __vlan_hwaccel_clear_tag(skb); 648 skb->dev = napi->dev; 649 skb->skb_iif = 0; 650 651 /* eth_type_trans() assumes pkt_type is PACKET_HOST */ 652 skb->pkt_type = PACKET_HOST; 653 654 skb->encapsulation = 0; 655 skb->ip_summed = CHECKSUM_NONE; 656 skb_shinfo(skb)->gso_type = 0; 657 skb_shinfo(skb)->gso_size = 0; 658 if (unlikely(skb->slow_gro)) { 659 skb_orphan(skb); 660 skb_ext_reset(skb); 661 nf_reset_ct(skb); 662 skb->slow_gro = 0; 663 } 664 665 napi->skb = skb; 666 } 667 668 struct sk_buff *napi_get_frags(struct napi_struct *napi) 669 { 670 struct sk_buff *skb = napi->skb; 671 672 if (!skb) { 673 skb = napi_alloc_skb(napi, GRO_MAX_HEAD); 674 if (skb) { 675 napi->skb = skb; 676 skb_mark_napi_id(skb, napi); 677 } 678 } 679 return skb; 680 } 681 EXPORT_SYMBOL(napi_get_frags); 682 683 static gro_result_t napi_frags_finish(struct napi_struct *napi, 684 struct sk_buff *skb, 685 gro_result_t ret) 686 { 687 switch (ret) { 688 case GRO_NORMAL: 689 case GRO_HELD: 690 __skb_push(skb, ETH_HLEN); 691 skb->protocol = eth_type_trans(skb, skb->dev); 692 if (ret == GRO_NORMAL) 693 gro_normal_one(&napi->gro, skb, 1); 694 break; 695 696 case GRO_MERGED_FREE: 697 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 698 napi_skb_free_stolen_head(skb); 699 else 700 napi_reuse_skb(napi, skb); 701 break; 702 703 case GRO_MERGED: 704 case GRO_CONSUMED: 705 break; 706 } 707 708 return ret; 709 } 710 711 /* Upper GRO stack assumes network header starts at gro_offset=0 712 * Drivers could call both napi_gro_frags() and napi_gro_receive() 713 * We copy ethernet header into skb->data to have a common layout. 714 */ 715 static struct sk_buff *napi_frags_skb(struct napi_struct *napi) 716 { 717 struct sk_buff *skb = napi->skb; 718 const struct ethhdr *eth; 719 unsigned int hlen = sizeof(*eth); 720 721 napi->skb = NULL; 722 723 skb_reset_mac_header(skb); 724 skb_gro_reset_offset(skb, hlen); 725 726 if (unlikely(!skb_gro_may_pull(skb, hlen))) { 727 eth = skb_gro_header_slow(skb, hlen, 0); 728 if (unlikely(!eth)) { 729 net_warn_ratelimited("%s: dropping impossible skb from %s\n", 730 __func__, napi->dev->name); 731 napi_reuse_skb(napi, skb); 732 return NULL; 733 } 734 } else { 735 eth = (const struct ethhdr *)skb->data; 736 737 if (NAPI_GRO_CB(skb)->frag0 != skb->data) 738 gro_pull_from_frag0(skb, hlen); 739 740 NAPI_GRO_CB(skb)->frag0 += hlen; 741 NAPI_GRO_CB(skb)->frag0_len -= hlen; 742 } 743 __skb_pull(skb, hlen); 744 745 /* 746 * This works because the only protocols we care about don't require 747 * special handling. 748 * We'll fix it up properly in napi_frags_finish() 749 */ 750 skb->protocol = eth->h_proto; 751 752 return skb; 753 } 754 755 gro_result_t napi_gro_frags(struct napi_struct *napi) 756 { 757 gro_result_t ret; 758 struct sk_buff *skb = napi_frags_skb(napi); 759 760 trace_napi_gro_frags_entry(skb); 761 762 ret = napi_frags_finish(napi, skb, dev_gro_receive(&napi->gro, skb)); 763 trace_napi_gro_frags_exit(ret); 764 765 return ret; 766 } 767 EXPORT_SYMBOL(napi_gro_frags); 768 769 /* Compute the checksum from gro_offset and return the folded value 770 * after adding in any pseudo checksum. 771 */ 772 __sum16 __skb_gro_checksum_complete(struct sk_buff *skb) 773 { 774 __wsum wsum; 775 __sum16 sum; 776 777 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0); 778 779 /* NAPI_GRO_CB(skb)->csum holds pseudo checksum */ 780 sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum)); 781 /* See comments in __skb_checksum_complete(). */ 782 if (likely(!sum)) { 783 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && 784 !skb->csum_complete_sw) 785 netdev_rx_csum_fault(skb->dev, skb); 786 } 787 788 NAPI_GRO_CB(skb)->csum = wsum; 789 NAPI_GRO_CB(skb)->csum_valid = 1; 790 791 return sum; 792 } 793 EXPORT_SYMBOL(__skb_gro_checksum_complete); 794 795 void gro_init(struct gro_node *gro) 796 { 797 for (u32 i = 0; i < GRO_HASH_BUCKETS; i++) { 798 INIT_LIST_HEAD(&gro->hash[i].list); 799 gro->hash[i].count = 0; 800 } 801 802 gro->bitmask = 0; 803 gro->cached_napi_id = 0; 804 805 INIT_LIST_HEAD(&gro->rx_list); 806 gro->rx_count = 0; 807 } 808 809 void gro_cleanup(struct gro_node *gro) 810 { 811 struct sk_buff *skb, *n; 812 813 for (u32 i = 0; i < GRO_HASH_BUCKETS; i++) { 814 list_for_each_entry_safe(skb, n, &gro->hash[i].list, list) 815 kfree_skb(skb); 816 817 gro->hash[i].count = 0; 818 } 819 820 gro->bitmask = 0; 821 gro->cached_napi_id = 0; 822 823 list_for_each_entry_safe(skb, n, &gro->rx_list, list) 824 kfree_skb(skb); 825 826 gro->rx_count = 0; 827 } 828