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