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 /* This should be increased if a protocol with a bigger head is added. */ 11 #define GRO_MAX_HEAD (MAX_HEADER + 128) 12 13 static DEFINE_SPINLOCK(offload_lock); 14 15 /** 16 * dev_add_offload - register offload handlers 17 * @po: protocol offload declaration 18 * 19 * Add protocol offload handlers to the networking stack. The passed 20 * &proto_offload is linked into kernel lists and may not be freed until 21 * it has been removed from the kernel lists. 22 * 23 * This call does not sleep therefore it can not 24 * guarantee all CPU's that are in middle of receiving packets 25 * will see the new offload handlers (until the next received packet). 26 */ 27 void dev_add_offload(struct packet_offload *po) 28 { 29 struct packet_offload *elem; 30 31 spin_lock(&offload_lock); 32 list_for_each_entry(elem, &net_hotdata.offload_base, list) { 33 if (po->priority < elem->priority) 34 break; 35 } 36 list_add_rcu(&po->list, elem->list.prev); 37 spin_unlock(&offload_lock); 38 } 39 EXPORT_SYMBOL(dev_add_offload); 40 41 /** 42 * __dev_remove_offload - remove offload handler 43 * @po: packet offload declaration 44 * 45 * Remove a protocol offload handler that was previously added to the 46 * kernel offload handlers by dev_add_offload(). The passed &offload_type 47 * is removed from the kernel lists and can be freed or reused once this 48 * function returns. 49 * 50 * The packet type might still be in use by receivers 51 * and must not be freed until after all the CPU's have gone 52 * through a quiescent state. 53 */ 54 static void __dev_remove_offload(struct packet_offload *po) 55 { 56 struct list_head *head = &net_hotdata.offload_base; 57 struct packet_offload *po1; 58 59 spin_lock(&offload_lock); 60 61 list_for_each_entry(po1, head, list) { 62 if (po == po1) { 63 list_del_rcu(&po->list); 64 goto out; 65 } 66 } 67 68 pr_warn("dev_remove_offload: %p not found\n", po); 69 out: 70 spin_unlock(&offload_lock); 71 } 72 73 /** 74 * dev_remove_offload - remove packet offload handler 75 * @po: packet offload declaration 76 * 77 * Remove a packet offload handler that was previously added to the kernel 78 * offload handlers by dev_add_offload(). The passed &offload_type is 79 * removed from the kernel lists and can be freed or reused once this 80 * function returns. 81 * 82 * This call sleeps to guarantee that no CPU is looking at the packet 83 * type after return. 84 */ 85 void dev_remove_offload(struct packet_offload *po) 86 { 87 __dev_remove_offload(po); 88 89 synchronize_net(); 90 } 91 EXPORT_SYMBOL(dev_remove_offload); 92 93 94 int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) 95 { 96 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb); 97 unsigned int offset = skb_gro_offset(skb); 98 unsigned int headlen = skb_headlen(skb); 99 unsigned int len = skb_gro_len(skb); 100 unsigned int delta_truesize; 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 if (unlikely(p->len + len >= netif_get_gro_max_size(p->dev, p) || 115 NAPI_GRO_CB(skb)->flush)) 116 return -E2BIG; 117 118 if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) { 119 if (NAPI_GRO_CB(skb)->proto != IPPROTO_TCP || 120 (p->protocol == htons(ETH_P_IPV6) && 121 skb_headroom(p) < sizeof(struct hop_jumbo_hdr)) || 122 p->encapsulation) 123 return -E2BIG; 124 } 125 126 segs = NAPI_GRO_CB(skb)->count; 127 lp = NAPI_GRO_CB(p)->last; 128 pinfo = skb_shinfo(lp); 129 130 if (headlen <= offset) { 131 skb_frag_t *frag; 132 skb_frag_t *frag2; 133 int i = skbinfo->nr_frags; 134 int nr_frags = pinfo->nr_frags + i; 135 136 if (nr_frags > MAX_SKB_FRAGS) 137 goto merge; 138 139 offset -= headlen; 140 pinfo->nr_frags = nr_frags; 141 skbinfo->nr_frags = 0; 142 143 frag = pinfo->frags + nr_frags; 144 frag2 = skbinfo->frags + i; 145 do { 146 *--frag = *--frag2; 147 } while (--i); 148 149 skb_frag_off_add(frag, offset); 150 skb_frag_size_sub(frag, offset); 151 152 /* all fragments truesize : remove (head size + sk_buff) */ 153 new_truesize = SKB_TRUESIZE(skb_end_offset(skb)); 154 delta_truesize = skb->truesize - new_truesize; 155 156 skb->truesize = new_truesize; 157 skb->len -= skb->data_len; 158 skb->data_len = 0; 159 160 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE; 161 goto done; 162 } else if (skb->head_frag) { 163 int nr_frags = pinfo->nr_frags; 164 skb_frag_t *frag = pinfo->frags + nr_frags; 165 struct page *page = virt_to_head_page(skb->head); 166 unsigned int first_size = headlen - offset; 167 unsigned int first_offset; 168 169 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) 170 goto merge; 171 172 first_offset = skb->data - 173 (unsigned char *)page_address(page) + 174 offset; 175 176 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; 177 178 skb_frag_fill_page_desc(frag, page, first_offset, first_size); 179 180 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); 181 /* We dont need to clear skbinfo->nr_frags here */ 182 183 new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff)); 184 delta_truesize = skb->truesize - new_truesize; 185 skb->truesize = new_truesize; 186 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; 187 goto done; 188 } 189 190 merge: 191 /* sk ownership - if any - completely transferred to the aggregated packet */ 192 skb->destructor = NULL; 193 skb->sk = NULL; 194 delta_truesize = skb->truesize; 195 if (offset > headlen) { 196 unsigned int eat = offset - headlen; 197 198 skb_frag_off_add(&skbinfo->frags[0], eat); 199 skb_frag_size_sub(&skbinfo->frags[0], eat); 200 skb->data_len -= eat; 201 skb->len -= eat; 202 offset = headlen; 203 } 204 205 __skb_pull(skb, offset); 206 207 if (NAPI_GRO_CB(p)->last == p) 208 skb_shinfo(p)->frag_list = skb; 209 else 210 NAPI_GRO_CB(p)->last->next = skb; 211 NAPI_GRO_CB(p)->last = skb; 212 __skb_header_release(skb); 213 lp = p; 214 215 done: 216 NAPI_GRO_CB(p)->count += segs; 217 p->data_len += len; 218 p->truesize += delta_truesize; 219 p->len += len; 220 if (lp != p) { 221 lp->data_len += len; 222 lp->truesize += delta_truesize; 223 lp->len += len; 224 } 225 NAPI_GRO_CB(skb)->same_flow = 1; 226 return 0; 227 } 228 229 int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb) 230 { 231 if (unlikely(p->len + skb->len >= 65536)) 232 return -E2BIG; 233 234 if (NAPI_GRO_CB(p)->last == p) 235 skb_shinfo(p)->frag_list = skb; 236 else 237 NAPI_GRO_CB(p)->last->next = skb; 238 239 skb_pull(skb, skb_gro_offset(skb)); 240 241 NAPI_GRO_CB(p)->last = skb; 242 NAPI_GRO_CB(p)->count++; 243 p->data_len += skb->len; 244 245 /* sk ownership - if any - completely transferred to the aggregated packet */ 246 skb->destructor = NULL; 247 skb->sk = NULL; 248 p->truesize += skb->truesize; 249 p->len += skb->len; 250 251 NAPI_GRO_CB(skb)->same_flow = 1; 252 253 return 0; 254 } 255 256 257 static void napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb) 258 { 259 struct list_head *head = &net_hotdata.offload_base; 260 struct packet_offload *ptype; 261 __be16 type = skb->protocol; 262 int err = -ENOENT; 263 264 BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb)); 265 266 if (NAPI_GRO_CB(skb)->count == 1) { 267 skb_shinfo(skb)->gso_size = 0; 268 goto out; 269 } 270 271 rcu_read_lock(); 272 list_for_each_entry_rcu(ptype, head, list) { 273 if (ptype->type != type || !ptype->callbacks.gro_complete) 274 continue; 275 276 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete, 277 ipv6_gro_complete, inet_gro_complete, 278 skb, 0); 279 break; 280 } 281 rcu_read_unlock(); 282 283 if (err) { 284 WARN_ON(&ptype->list == head); 285 kfree_skb(skb); 286 return; 287 } 288 289 out: 290 gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count); 291 } 292 293 static void __napi_gro_flush_chain(struct napi_struct *napi, u32 index, 294 bool flush_old) 295 { 296 struct list_head *head = &napi->gro_hash[index].list; 297 struct sk_buff *skb, *p; 298 299 list_for_each_entry_safe_reverse(skb, p, head, list) { 300 if (flush_old && NAPI_GRO_CB(skb)->age == jiffies) 301 return; 302 skb_list_del_init(skb); 303 napi_gro_complete(napi, skb); 304 napi->gro_hash[index].count--; 305 } 306 307 if (!napi->gro_hash[index].count) 308 __clear_bit(index, &napi->gro_bitmask); 309 } 310 311 /* napi->gro_hash[].list contains packets ordered by age. 312 * youngest packets at the head of it. 313 * Complete skbs in reverse order to reduce latencies. 314 */ 315 void napi_gro_flush(struct napi_struct *napi, bool flush_old) 316 { 317 unsigned long bitmask = napi->gro_bitmask; 318 unsigned int i, base = ~0U; 319 320 while ((i = ffs(bitmask)) != 0) { 321 bitmask >>= i; 322 base += i; 323 __napi_gro_flush_chain(napi, base, flush_old); 324 } 325 } 326 EXPORT_SYMBOL(napi_gro_flush); 327 328 static unsigned long gro_list_prepare_tc_ext(const struct sk_buff *skb, 329 const struct sk_buff *p, 330 unsigned long diffs) 331 { 332 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 333 struct tc_skb_ext *skb_ext; 334 struct tc_skb_ext *p_ext; 335 336 skb_ext = skb_ext_find(skb, TC_SKB_EXT); 337 p_ext = skb_ext_find(p, TC_SKB_EXT); 338 339 diffs |= (!!p_ext) ^ (!!skb_ext); 340 if (!diffs && unlikely(skb_ext)) 341 diffs |= p_ext->chain ^ skb_ext->chain; 342 #endif 343 return diffs; 344 } 345 346 static void gro_list_prepare(const struct list_head *head, 347 const struct sk_buff *skb) 348 { 349 unsigned int maclen = skb->dev->hard_header_len; 350 u32 hash = skb_get_hash_raw(skb); 351 struct sk_buff *p; 352 353 list_for_each_entry(p, head, list) { 354 unsigned long diffs; 355 356 if (hash != skb_get_hash_raw(p)) { 357 NAPI_GRO_CB(p)->same_flow = 0; 358 continue; 359 } 360 361 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; 362 diffs |= p->vlan_all ^ skb->vlan_all; 363 diffs |= skb_metadata_differs(p, skb); 364 if (maclen == ETH_HLEN) 365 diffs |= compare_ether_header(skb_mac_header(p), 366 skb_mac_header(skb)); 367 else if (!diffs) 368 diffs = memcmp(skb_mac_header(p), 369 skb_mac_header(skb), 370 maclen); 371 372 /* in most common scenarios 'slow_gro' is 0 373 * otherwise we are already on some slower paths 374 * either skip all the infrequent tests altogether or 375 * avoid trying too hard to skip each of them individually 376 */ 377 if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) { 378 diffs |= p->sk != skb->sk; 379 diffs |= skb_metadata_dst_cmp(p, skb); 380 diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb); 381 382 diffs |= gro_list_prepare_tc_ext(skb, p, diffs); 383 } 384 385 NAPI_GRO_CB(p)->same_flow = !diffs; 386 } 387 } 388 389 static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff) 390 { 391 const struct skb_shared_info *pinfo; 392 const skb_frag_t *frag0; 393 unsigned int headlen; 394 395 NAPI_GRO_CB(skb)->network_offset = 0; 396 NAPI_GRO_CB(skb)->data_offset = 0; 397 headlen = skb_headlen(skb); 398 NAPI_GRO_CB(skb)->frag0 = skb->data; 399 NAPI_GRO_CB(skb)->frag0_len = headlen; 400 if (headlen) 401 return; 402 403 pinfo = skb_shinfo(skb); 404 frag0 = &pinfo->frags[0]; 405 406 if (pinfo->nr_frags && skb_frag_page(frag0) && 407 !PageHighMem(skb_frag_page(frag0)) && 408 (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) { 409 NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); 410 NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, 411 skb_frag_size(frag0), 412 skb->end - skb->tail); 413 } 414 } 415 416 static void gro_pull_from_frag0(struct sk_buff *skb, int grow) 417 { 418 struct skb_shared_info *pinfo = skb_shinfo(skb); 419 420 BUG_ON(skb->end - skb->tail < grow); 421 422 memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow); 423 424 skb->data_len -= grow; 425 skb->tail += grow; 426 427 skb_frag_off_add(&pinfo->frags[0], grow); 428 skb_frag_size_sub(&pinfo->frags[0], grow); 429 430 if (unlikely(!skb_frag_size(&pinfo->frags[0]))) { 431 skb_frag_unref(skb, 0); 432 memmove(pinfo->frags, pinfo->frags + 1, 433 --pinfo->nr_frags * sizeof(pinfo->frags[0])); 434 } 435 } 436 437 static void gro_try_pull_from_frag0(struct sk_buff *skb) 438 { 439 int grow = skb_gro_offset(skb) - skb_headlen(skb); 440 441 if (grow > 0) 442 gro_pull_from_frag0(skb, grow); 443 } 444 445 static void gro_flush_oldest(struct napi_struct *napi, struct list_head *head) 446 { 447 struct sk_buff *oldest; 448 449 oldest = list_last_entry(head, struct sk_buff, list); 450 451 /* We are called with head length >= MAX_GRO_SKBS, so this is 452 * impossible. 453 */ 454 if (WARN_ON_ONCE(!oldest)) 455 return; 456 457 /* Do not adjust napi->gro_hash[].count, caller is adding a new 458 * SKB to the chain. 459 */ 460 skb_list_del_init(oldest); 461 napi_gro_complete(napi, oldest); 462 } 463 464 static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 465 { 466 u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1); 467 struct gro_list *gro_list = &napi->gro_hash[bucket]; 468 struct list_head *head = &net_hotdata.offload_base; 469 struct packet_offload *ptype; 470 __be16 type = skb->protocol; 471 struct sk_buff *pp = NULL; 472 enum gro_result ret; 473 int same_flow; 474 475 if (netif_elide_gro(skb->dev)) 476 goto normal; 477 478 gro_list_prepare(&gro_list->list, skb); 479 480 rcu_read_lock(); 481 list_for_each_entry_rcu(ptype, head, list) { 482 if (ptype->type == type && ptype->callbacks.gro_receive) 483 goto found_ptype; 484 } 485 rcu_read_unlock(); 486 goto normal; 487 488 found_ptype: 489 skb_set_network_header(skb, skb_gro_offset(skb)); 490 skb_reset_mac_len(skb); 491 BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32)); 492 BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed), 493 sizeof(u32))); /* Avoid slow unaligned acc */ 494 *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0; 495 NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb); 496 NAPI_GRO_CB(skb)->count = 1; 497 if (unlikely(skb_is_gso(skb))) { 498 NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs; 499 /* Only support TCP and non DODGY users. */ 500 if (!skb_is_gso_tcp(skb) || 501 (skb_shinfo(skb)->gso_type & SKB_GSO_DODGY)) 502 NAPI_GRO_CB(skb)->flush = 1; 503 } 504 505 /* Setup for GRO checksum validation */ 506 switch (skb->ip_summed) { 507 case CHECKSUM_COMPLETE: 508 NAPI_GRO_CB(skb)->csum = skb->csum; 509 NAPI_GRO_CB(skb)->csum_valid = 1; 510 break; 511 case CHECKSUM_UNNECESSARY: 512 NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1; 513 break; 514 } 515 516 pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive, 517 ipv6_gro_receive, inet_gro_receive, 518 &gro_list->list, skb); 519 520 rcu_read_unlock(); 521 522 if (PTR_ERR(pp) == -EINPROGRESS) { 523 ret = GRO_CONSUMED; 524 goto ok; 525 } 526 527 same_flow = NAPI_GRO_CB(skb)->same_flow; 528 ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED; 529 530 if (pp) { 531 skb_list_del_init(pp); 532 napi_gro_complete(napi, pp); 533 gro_list->count--; 534 } 535 536 if (same_flow) 537 goto ok; 538 539 if (NAPI_GRO_CB(skb)->flush) 540 goto normal; 541 542 if (unlikely(gro_list->count >= MAX_GRO_SKBS)) 543 gro_flush_oldest(napi, &gro_list->list); 544 else 545 gro_list->count++; 546 547 /* Must be called before setting NAPI_GRO_CB(skb)->{age|last} */ 548 gro_try_pull_from_frag0(skb); 549 NAPI_GRO_CB(skb)->age = jiffies; 550 NAPI_GRO_CB(skb)->last = skb; 551 if (!skb_is_gso(skb)) 552 skb_shinfo(skb)->gso_size = skb_gro_len(skb); 553 list_add(&skb->list, &gro_list->list); 554 ret = GRO_HELD; 555 ok: 556 if (gro_list->count) { 557 if (!test_bit(bucket, &napi->gro_bitmask)) 558 __set_bit(bucket, &napi->gro_bitmask); 559 } else if (test_bit(bucket, &napi->gro_bitmask)) { 560 __clear_bit(bucket, &napi->gro_bitmask); 561 } 562 563 return ret; 564 565 normal: 566 ret = GRO_NORMAL; 567 gro_try_pull_from_frag0(skb); 568 goto ok; 569 } 570 571 struct packet_offload *gro_find_receive_by_type(__be16 type) 572 { 573 struct list_head *offload_head = &net_hotdata.offload_base; 574 struct packet_offload *ptype; 575 576 list_for_each_entry_rcu(ptype, offload_head, list) { 577 if (ptype->type != type || !ptype->callbacks.gro_receive) 578 continue; 579 return ptype; 580 } 581 return NULL; 582 } 583 EXPORT_SYMBOL(gro_find_receive_by_type); 584 585 struct packet_offload *gro_find_complete_by_type(__be16 type) 586 { 587 struct list_head *offload_head = &net_hotdata.offload_base; 588 struct packet_offload *ptype; 589 590 list_for_each_entry_rcu(ptype, offload_head, list) { 591 if (ptype->type != type || !ptype->callbacks.gro_complete) 592 continue; 593 return ptype; 594 } 595 return NULL; 596 } 597 EXPORT_SYMBOL(gro_find_complete_by_type); 598 599 static gro_result_t napi_skb_finish(struct napi_struct *napi, 600 struct sk_buff *skb, 601 gro_result_t ret) 602 { 603 switch (ret) { 604 case GRO_NORMAL: 605 gro_normal_one(napi, skb, 1); 606 break; 607 608 case GRO_MERGED_FREE: 609 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 610 napi_skb_free_stolen_head(skb); 611 else if (skb->fclone != SKB_FCLONE_UNAVAILABLE) 612 __kfree_skb(skb); 613 else 614 __napi_kfree_skb(skb, SKB_CONSUMED); 615 break; 616 617 case GRO_HELD: 618 case GRO_MERGED: 619 case GRO_CONSUMED: 620 break; 621 } 622 623 return ret; 624 } 625 626 gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 627 { 628 gro_result_t ret; 629 630 skb_mark_napi_id(skb, napi); 631 trace_napi_gro_receive_entry(skb); 632 633 skb_gro_reset_offset(skb, 0); 634 635 ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb)); 636 trace_napi_gro_receive_exit(ret); 637 638 return ret; 639 } 640 EXPORT_SYMBOL(napi_gro_receive); 641 642 static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) 643 { 644 if (unlikely(skb->pfmemalloc)) { 645 consume_skb(skb); 646 return; 647 } 648 __skb_pull(skb, skb_headlen(skb)); 649 /* restore the reserve we had after netdev_alloc_skb_ip_align() */ 650 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb)); 651 __vlan_hwaccel_clear_tag(skb); 652 skb->dev = napi->dev; 653 skb->skb_iif = 0; 654 655 /* eth_type_trans() assumes pkt_type is PACKET_HOST */ 656 skb->pkt_type = PACKET_HOST; 657 658 skb->encapsulation = 0; 659 skb_shinfo(skb)->gso_type = 0; 660 skb_shinfo(skb)->gso_size = 0; 661 if (unlikely(skb->slow_gro)) { 662 skb_orphan(skb); 663 skb_ext_reset(skb); 664 nf_reset_ct(skb); 665 skb->slow_gro = 0; 666 } 667 668 napi->skb = skb; 669 } 670 671 struct sk_buff *napi_get_frags(struct napi_struct *napi) 672 { 673 struct sk_buff *skb = napi->skb; 674 675 if (!skb) { 676 skb = napi_alloc_skb(napi, GRO_MAX_HEAD); 677 if (skb) { 678 napi->skb = skb; 679 skb_mark_napi_id(skb, napi); 680 } 681 } 682 return skb; 683 } 684 EXPORT_SYMBOL(napi_get_frags); 685 686 static gro_result_t napi_frags_finish(struct napi_struct *napi, 687 struct sk_buff *skb, 688 gro_result_t ret) 689 { 690 switch (ret) { 691 case GRO_NORMAL: 692 case GRO_HELD: 693 __skb_push(skb, ETH_HLEN); 694 skb->protocol = eth_type_trans(skb, skb->dev); 695 if (ret == GRO_NORMAL) 696 gro_normal_one(napi, skb, 1); 697 break; 698 699 case GRO_MERGED_FREE: 700 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 701 napi_skb_free_stolen_head(skb); 702 else 703 napi_reuse_skb(napi, skb); 704 break; 705 706 case GRO_MERGED: 707 case GRO_CONSUMED: 708 break; 709 } 710 711 return ret; 712 } 713 714 /* Upper GRO stack assumes network header starts at gro_offset=0 715 * Drivers could call both napi_gro_frags() and napi_gro_receive() 716 * We copy ethernet header into skb->data to have a common layout. 717 */ 718 static struct sk_buff *napi_frags_skb(struct napi_struct *napi) 719 { 720 struct sk_buff *skb = napi->skb; 721 const struct ethhdr *eth; 722 unsigned int hlen = sizeof(*eth); 723 724 napi->skb = NULL; 725 726 skb_reset_mac_header(skb); 727 skb_gro_reset_offset(skb, hlen); 728 729 if (unlikely(!skb_gro_may_pull(skb, hlen))) { 730 eth = skb_gro_header_slow(skb, hlen, 0); 731 if (unlikely(!eth)) { 732 net_warn_ratelimited("%s: dropping impossible skb from %s\n", 733 __func__, napi->dev->name); 734 napi_reuse_skb(napi, skb); 735 return NULL; 736 } 737 } else { 738 eth = (const struct ethhdr *)skb->data; 739 740 if (NAPI_GRO_CB(skb)->frag0 != skb->data) 741 gro_pull_from_frag0(skb, hlen); 742 743 NAPI_GRO_CB(skb)->frag0 += hlen; 744 NAPI_GRO_CB(skb)->frag0_len -= hlen; 745 } 746 __skb_pull(skb, hlen); 747 748 /* 749 * This works because the only protocols we care about don't require 750 * special handling. 751 * We'll fix it up properly in napi_frags_finish() 752 */ 753 skb->protocol = eth->h_proto; 754 755 return skb; 756 } 757 758 gro_result_t napi_gro_frags(struct napi_struct *napi) 759 { 760 gro_result_t ret; 761 struct sk_buff *skb = napi_frags_skb(napi); 762 763 trace_napi_gro_frags_entry(skb); 764 765 ret = napi_frags_finish(napi, skb, dev_gro_receive(napi, skb)); 766 trace_napi_gro_frags_exit(ret); 767 768 return ret; 769 } 770 EXPORT_SYMBOL(napi_gro_frags); 771 772 /* Compute the checksum from gro_offset and return the folded value 773 * after adding in any pseudo checksum. 774 */ 775 __sum16 __skb_gro_checksum_complete(struct sk_buff *skb) 776 { 777 __wsum wsum; 778 __sum16 sum; 779 780 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0); 781 782 /* NAPI_GRO_CB(skb)->csum holds pseudo checksum */ 783 sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum)); 784 /* See comments in __skb_checksum_complete(). */ 785 if (likely(!sum)) { 786 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && 787 !skb->csum_complete_sw) 788 netdev_rx_csum_fault(skb->dev, skb); 789 } 790 791 NAPI_GRO_CB(skb)->csum = wsum; 792 NAPI_GRO_CB(skb)->csum_valid = 1; 793 794 return sum; 795 } 796 EXPORT_SYMBOL(__skb_gro_checksum_complete); 797