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 /* pairs with WRITE_ONCE() in netif_set_gro_max_size() */ 166 gro_max_size = READ_ONCE(p->dev->gro_max_size); 167 168 if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush)) 169 return -E2BIG; 170 171 if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) { 172 if (p->protocol != htons(ETH_P_IPV6) || 173 skb_headroom(p) < sizeof(struct hop_jumbo_hdr) || 174 ipv6_hdr(p)->nexthdr != IPPROTO_TCP || 175 p->encapsulation) 176 return -E2BIG; 177 } 178 179 segs = NAPI_GRO_CB(skb)->count; 180 lp = NAPI_GRO_CB(p)->last; 181 pinfo = skb_shinfo(lp); 182 183 if (headlen <= offset) { 184 skb_frag_t *frag; 185 skb_frag_t *frag2; 186 int i = skbinfo->nr_frags; 187 int nr_frags = pinfo->nr_frags + i; 188 189 if (nr_frags > MAX_SKB_FRAGS) 190 goto merge; 191 192 offset -= headlen; 193 pinfo->nr_frags = nr_frags; 194 skbinfo->nr_frags = 0; 195 196 frag = pinfo->frags + nr_frags; 197 frag2 = skbinfo->frags + i; 198 do { 199 *--frag = *--frag2; 200 } while (--i); 201 202 skb_frag_off_add(frag, offset); 203 skb_frag_size_sub(frag, offset); 204 205 /* all fragments truesize : remove (head size + sk_buff) */ 206 new_truesize = SKB_TRUESIZE(skb_end_offset(skb)); 207 delta_truesize = skb->truesize - new_truesize; 208 209 skb->truesize = new_truesize; 210 skb->len -= skb->data_len; 211 skb->data_len = 0; 212 213 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE; 214 goto done; 215 } else if (skb->head_frag) { 216 int nr_frags = pinfo->nr_frags; 217 skb_frag_t *frag = pinfo->frags + nr_frags; 218 struct page *page = virt_to_head_page(skb->head); 219 unsigned int first_size = headlen - offset; 220 unsigned int first_offset; 221 222 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) 223 goto merge; 224 225 first_offset = skb->data - 226 (unsigned char *)page_address(page) + 227 offset; 228 229 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; 230 231 __skb_frag_set_page(frag, page); 232 skb_frag_off_set(frag, first_offset); 233 skb_frag_size_set(frag, first_size); 234 235 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); 236 /* We dont need to clear skbinfo->nr_frags here */ 237 238 new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff)); 239 delta_truesize = skb->truesize - new_truesize; 240 skb->truesize = new_truesize; 241 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; 242 goto done; 243 } 244 245 merge: 246 /* sk owenrship - if any - completely transferred to the aggregated packet */ 247 skb->destructor = NULL; 248 delta_truesize = skb->truesize; 249 if (offset > headlen) { 250 unsigned int eat = offset - headlen; 251 252 skb_frag_off_add(&skbinfo->frags[0], eat); 253 skb_frag_size_sub(&skbinfo->frags[0], eat); 254 skb->data_len -= eat; 255 skb->len -= eat; 256 offset = headlen; 257 } 258 259 __skb_pull(skb, offset); 260 261 if (NAPI_GRO_CB(p)->last == p) 262 skb_shinfo(p)->frag_list = skb; 263 else 264 NAPI_GRO_CB(p)->last->next = skb; 265 NAPI_GRO_CB(p)->last = skb; 266 __skb_header_release(skb); 267 lp = p; 268 269 done: 270 NAPI_GRO_CB(p)->count += segs; 271 p->data_len += len; 272 p->truesize += delta_truesize; 273 p->len += len; 274 if (lp != p) { 275 lp->data_len += len; 276 lp->truesize += delta_truesize; 277 lp->len += len; 278 } 279 NAPI_GRO_CB(skb)->same_flow = 1; 280 return 0; 281 } 282 283 284 static void napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb) 285 { 286 struct packet_offload *ptype; 287 __be16 type = skb->protocol; 288 struct list_head *head = &offload_base; 289 int err = -ENOENT; 290 291 BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb)); 292 293 if (NAPI_GRO_CB(skb)->count == 1) { 294 skb_shinfo(skb)->gso_size = 0; 295 goto out; 296 } 297 298 rcu_read_lock(); 299 list_for_each_entry_rcu(ptype, head, list) { 300 if (ptype->type != type || !ptype->callbacks.gro_complete) 301 continue; 302 303 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete, 304 ipv6_gro_complete, inet_gro_complete, 305 skb, 0); 306 break; 307 } 308 rcu_read_unlock(); 309 310 if (err) { 311 WARN_ON(&ptype->list == head); 312 kfree_skb(skb); 313 return; 314 } 315 316 out: 317 gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count); 318 } 319 320 static void __napi_gro_flush_chain(struct napi_struct *napi, u32 index, 321 bool flush_old) 322 { 323 struct list_head *head = &napi->gro_hash[index].list; 324 struct sk_buff *skb, *p; 325 326 list_for_each_entry_safe_reverse(skb, p, head, list) { 327 if (flush_old && NAPI_GRO_CB(skb)->age == jiffies) 328 return; 329 skb_list_del_init(skb); 330 napi_gro_complete(napi, skb); 331 napi->gro_hash[index].count--; 332 } 333 334 if (!napi->gro_hash[index].count) 335 __clear_bit(index, &napi->gro_bitmask); 336 } 337 338 /* napi->gro_hash[].list contains packets ordered by age. 339 * youngest packets at the head of it. 340 * Complete skbs in reverse order to reduce latencies. 341 */ 342 void napi_gro_flush(struct napi_struct *napi, bool flush_old) 343 { 344 unsigned long bitmask = napi->gro_bitmask; 345 unsigned int i, base = ~0U; 346 347 while ((i = ffs(bitmask)) != 0) { 348 bitmask >>= i; 349 base += i; 350 __napi_gro_flush_chain(napi, base, flush_old); 351 } 352 } 353 EXPORT_SYMBOL(napi_gro_flush); 354 355 static void gro_list_prepare(const struct list_head *head, 356 const struct sk_buff *skb) 357 { 358 unsigned int maclen = skb->dev->hard_header_len; 359 u32 hash = skb_get_hash_raw(skb); 360 struct sk_buff *p; 361 362 list_for_each_entry(p, head, list) { 363 unsigned long diffs; 364 365 NAPI_GRO_CB(p)->flush = 0; 366 367 if (hash != skb_get_hash_raw(p)) { 368 NAPI_GRO_CB(p)->same_flow = 0; 369 continue; 370 } 371 372 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; 373 diffs |= p->vlan_all ^ skb->vlan_all; 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 goto found_ptype; 492 } 493 rcu_read_unlock(); 494 goto normal; 495 496 found_ptype: 497 skb_set_network_header(skb, skb_gro_offset(skb)); 498 skb_reset_mac_len(skb); 499 BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32)); 500 BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed), 501 sizeof(u32))); /* Avoid slow unaligned acc */ 502 *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0; 503 NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb); 504 NAPI_GRO_CB(skb)->is_atomic = 1; 505 NAPI_GRO_CB(skb)->count = 1; 506 if (unlikely(skb_is_gso(skb))) { 507 NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs; 508 /* Only support TCP and non DODGY users. */ 509 if (!skb_is_gso_tcp(skb) || 510 (skb_shinfo(skb)->gso_type & SKB_GSO_DODGY)) 511 NAPI_GRO_CB(skb)->flush = 1; 512 } 513 514 /* Setup for GRO checksum validation */ 515 switch (skb->ip_summed) { 516 case CHECKSUM_COMPLETE: 517 NAPI_GRO_CB(skb)->csum = skb->csum; 518 NAPI_GRO_CB(skb)->csum_valid = 1; 519 break; 520 case CHECKSUM_UNNECESSARY: 521 NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1; 522 break; 523 } 524 525 pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive, 526 ipv6_gro_receive, inet_gro_receive, 527 &gro_list->list, skb); 528 529 rcu_read_unlock(); 530 531 if (PTR_ERR(pp) == -EINPROGRESS) { 532 ret = GRO_CONSUMED; 533 goto ok; 534 } 535 536 same_flow = NAPI_GRO_CB(skb)->same_flow; 537 ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED; 538 539 if (pp) { 540 skb_list_del_init(pp); 541 napi_gro_complete(napi, pp); 542 gro_list->count--; 543 } 544 545 if (same_flow) 546 goto ok; 547 548 if (NAPI_GRO_CB(skb)->flush) 549 goto normal; 550 551 if (unlikely(gro_list->count >= MAX_GRO_SKBS)) 552 gro_flush_oldest(napi, &gro_list->list); 553 else 554 gro_list->count++; 555 556 NAPI_GRO_CB(skb)->age = jiffies; 557 NAPI_GRO_CB(skb)->last = skb; 558 if (!skb_is_gso(skb)) 559 skb_shinfo(skb)->gso_size = skb_gro_len(skb); 560 list_add(&skb->list, &gro_list->list); 561 ret = GRO_HELD; 562 563 pull: 564 grow = skb_gro_offset(skb) - skb_headlen(skb); 565 if (grow > 0) 566 gro_pull_from_frag0(skb, grow); 567 ok: 568 if (gro_list->count) { 569 if (!test_bit(bucket, &napi->gro_bitmask)) 570 __set_bit(bucket, &napi->gro_bitmask); 571 } else if (test_bit(bucket, &napi->gro_bitmask)) { 572 __clear_bit(bucket, &napi->gro_bitmask); 573 } 574 575 return ret; 576 577 normal: 578 ret = GRO_NORMAL; 579 goto pull; 580 } 581 582 struct packet_offload *gro_find_receive_by_type(__be16 type) 583 { 584 struct list_head *offload_head = &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_receive) 589 continue; 590 return ptype; 591 } 592 return NULL; 593 } 594 EXPORT_SYMBOL(gro_find_receive_by_type); 595 596 struct packet_offload *gro_find_complete_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_complete) 603 continue; 604 return ptype; 605 } 606 return NULL; 607 } 608 EXPORT_SYMBOL(gro_find_complete_by_type); 609 610 static gro_result_t napi_skb_finish(struct napi_struct *napi, 611 struct sk_buff *skb, 612 gro_result_t ret) 613 { 614 switch (ret) { 615 case GRO_NORMAL: 616 gro_normal_one(napi, skb, 1); 617 break; 618 619 case GRO_MERGED_FREE: 620 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 621 napi_skb_free_stolen_head(skb); 622 else if (skb->fclone != SKB_FCLONE_UNAVAILABLE) 623 __kfree_skb(skb); 624 else 625 __kfree_skb_defer(skb); 626 break; 627 628 case GRO_HELD: 629 case GRO_MERGED: 630 case GRO_CONSUMED: 631 break; 632 } 633 634 return ret; 635 } 636 637 gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb) 638 { 639 gro_result_t ret; 640 641 skb_mark_napi_id(skb, napi); 642 trace_napi_gro_receive_entry(skb); 643 644 skb_gro_reset_offset(skb, 0); 645 646 ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb)); 647 trace_napi_gro_receive_exit(ret); 648 649 return ret; 650 } 651 EXPORT_SYMBOL(napi_gro_receive); 652 653 static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) 654 { 655 if (unlikely(skb->pfmemalloc)) { 656 consume_skb(skb); 657 return; 658 } 659 __skb_pull(skb, skb_headlen(skb)); 660 /* restore the reserve we had after netdev_alloc_skb_ip_align() */ 661 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb)); 662 __vlan_hwaccel_clear_tag(skb); 663 skb->dev = napi->dev; 664 skb->skb_iif = 0; 665 666 /* eth_type_trans() assumes pkt_type is PACKET_HOST */ 667 skb->pkt_type = PACKET_HOST; 668 669 skb->encapsulation = 0; 670 skb_shinfo(skb)->gso_type = 0; 671 skb_shinfo(skb)->gso_size = 0; 672 if (unlikely(skb->slow_gro)) { 673 skb_orphan(skb); 674 skb_ext_reset(skb); 675 nf_reset_ct(skb); 676 skb->slow_gro = 0; 677 } 678 679 napi->skb = skb; 680 } 681 682 struct sk_buff *napi_get_frags(struct napi_struct *napi) 683 { 684 struct sk_buff *skb = napi->skb; 685 686 if (!skb) { 687 skb = napi_alloc_skb(napi, GRO_MAX_HEAD); 688 if (skb) { 689 napi->skb = skb; 690 skb_mark_napi_id(skb, napi); 691 } 692 } 693 return skb; 694 } 695 EXPORT_SYMBOL(napi_get_frags); 696 697 static gro_result_t napi_frags_finish(struct napi_struct *napi, 698 struct sk_buff *skb, 699 gro_result_t ret) 700 { 701 switch (ret) { 702 case GRO_NORMAL: 703 case GRO_HELD: 704 __skb_push(skb, ETH_HLEN); 705 skb->protocol = eth_type_trans(skb, skb->dev); 706 if (ret == GRO_NORMAL) 707 gro_normal_one(napi, skb, 1); 708 break; 709 710 case GRO_MERGED_FREE: 711 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) 712 napi_skb_free_stolen_head(skb); 713 else 714 napi_reuse_skb(napi, skb); 715 break; 716 717 case GRO_MERGED: 718 case GRO_CONSUMED: 719 break; 720 } 721 722 return ret; 723 } 724 725 /* Upper GRO stack assumes network header starts at gro_offset=0 726 * Drivers could call both napi_gro_frags() and napi_gro_receive() 727 * We copy ethernet header into skb->data to have a common layout. 728 */ 729 static struct sk_buff *napi_frags_skb(struct napi_struct *napi) 730 { 731 struct sk_buff *skb = napi->skb; 732 const struct ethhdr *eth; 733 unsigned int hlen = sizeof(*eth); 734 735 napi->skb = NULL; 736 737 skb_reset_mac_header(skb); 738 skb_gro_reset_offset(skb, hlen); 739 740 if (unlikely(skb_gro_header_hard(skb, hlen))) { 741 eth = skb_gro_header_slow(skb, hlen, 0); 742 if (unlikely(!eth)) { 743 net_warn_ratelimited("%s: dropping impossible skb from %s\n", 744 __func__, napi->dev->name); 745 napi_reuse_skb(napi, skb); 746 return NULL; 747 } 748 } else { 749 eth = (const struct ethhdr *)skb->data; 750 gro_pull_from_frag0(skb, hlen); 751 NAPI_GRO_CB(skb)->frag0 += hlen; 752 NAPI_GRO_CB(skb)->frag0_len -= hlen; 753 } 754 __skb_pull(skb, hlen); 755 756 /* 757 * This works because the only protocols we care about don't require 758 * special handling. 759 * We'll fix it up properly in napi_frags_finish() 760 */ 761 skb->protocol = eth->h_proto; 762 763 return skb; 764 } 765 766 gro_result_t napi_gro_frags(struct napi_struct *napi) 767 { 768 gro_result_t ret; 769 struct sk_buff *skb = napi_frags_skb(napi); 770 771 trace_napi_gro_frags_entry(skb); 772 773 ret = napi_frags_finish(napi, skb, dev_gro_receive(napi, skb)); 774 trace_napi_gro_frags_exit(ret); 775 776 return ret; 777 } 778 EXPORT_SYMBOL(napi_gro_frags); 779 780 /* Compute the checksum from gro_offset and return the folded value 781 * after adding in any pseudo checksum. 782 */ 783 __sum16 __skb_gro_checksum_complete(struct sk_buff *skb) 784 { 785 __wsum wsum; 786 __sum16 sum; 787 788 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0); 789 790 /* NAPI_GRO_CB(skb)->csum holds pseudo checksum */ 791 sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum)); 792 /* See comments in __skb_checksum_complete(). */ 793 if (likely(!sum)) { 794 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && 795 !skb->csum_complete_sw) 796 netdev_rx_csum_fault(skb->dev, skb); 797 } 798 799 NAPI_GRO_CB(skb)->csum = wsum; 800 NAPI_GRO_CB(skb)->csum_valid = 1; 801 802 return sum; 803 } 804 EXPORT_SYMBOL(__skb_gro_checksum_complete); 805