1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * inet fragments management 4 * 5 * Authors: Pavel Emelyanov <xemul@openvz.org> 6 * Started as consolidation of ipv4/ip_fragment.c, 7 * ipv6/reassembly. and ipv6 nf conntrack reassembly 8 */ 9 10 #include <linux/list.h> 11 #include <linux/spinlock.h> 12 #include <linux/module.h> 13 #include <linux/timer.h> 14 #include <linux/mm.h> 15 #include <linux/random.h> 16 #include <linux/skbuff.h> 17 #include <linux/rtnetlink.h> 18 #include <linux/slab.h> 19 #include <linux/rhashtable.h> 20 21 #include <net/sock.h> 22 #include <net/inet_frag.h> 23 #include <net/inet_ecn.h> 24 #include <net/ip.h> 25 #include <net/ipv6.h> 26 27 #include "../core/sock_destructor.h" 28 29 /* Use skb->cb to track consecutive/adjacent fragments coming at 30 * the end of the queue. Nodes in the rb-tree queue will 31 * contain "runs" of one or more adjacent fragments. 32 * 33 * Invariants: 34 * - next_frag is NULL at the tail of a "run"; 35 * - the head of a "run" has the sum of all fragment lengths in frag_run_len. 36 */ 37 struct ipfrag_skb_cb { 38 union { 39 struct inet_skb_parm h4; 40 struct inet6_skb_parm h6; 41 }; 42 struct sk_buff *next_frag; 43 int frag_run_len; 44 int ip_defrag_offset; 45 }; 46 47 #define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb)) 48 49 static void fragcb_clear(struct sk_buff *skb) 50 { 51 RB_CLEAR_NODE(&skb->rbnode); 52 FRAG_CB(skb)->next_frag = NULL; 53 FRAG_CB(skb)->frag_run_len = skb->len; 54 } 55 56 /* Append skb to the last "run". */ 57 static void fragrun_append_to_last(struct inet_frag_queue *q, 58 struct sk_buff *skb) 59 { 60 fragcb_clear(skb); 61 62 FRAG_CB(q->last_run_head)->frag_run_len += skb->len; 63 FRAG_CB(q->fragments_tail)->next_frag = skb; 64 q->fragments_tail = skb; 65 } 66 67 /* Create a new "run" with the skb. */ 68 static void fragrun_create(struct inet_frag_queue *q, struct sk_buff *skb) 69 { 70 BUILD_BUG_ON(sizeof(struct ipfrag_skb_cb) > sizeof(skb->cb)); 71 fragcb_clear(skb); 72 73 if (q->last_run_head) 74 rb_link_node(&skb->rbnode, &q->last_run_head->rbnode, 75 &q->last_run_head->rbnode.rb_right); 76 else 77 rb_link_node(&skb->rbnode, NULL, &q->rb_fragments.rb_node); 78 rb_insert_color(&skb->rbnode, &q->rb_fragments); 79 80 q->fragments_tail = skb; 81 q->last_run_head = skb; 82 } 83 84 /* Given the OR values of all fragments, apply RFC 3168 5.3 requirements 85 * Value : 0xff if frame should be dropped. 86 * 0 or INET_ECN_CE value, to be ORed in to final iph->tos field 87 */ 88 const u8 ip_frag_ecn_table[16] = { 89 /* at least one fragment had CE, and others ECT_0 or ECT_1 */ 90 [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = INET_ECN_CE, 91 [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = INET_ECN_CE, 92 [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = INET_ECN_CE, 93 94 /* invalid combinations : drop frame */ 95 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff, 96 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff, 97 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff, 98 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff, 99 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff, 100 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff, 101 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff, 102 }; 103 EXPORT_SYMBOL(ip_frag_ecn_table); 104 105 int inet_frags_init(struct inet_frags *f) 106 { 107 f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0, 108 NULL); 109 if (!f->frags_cachep) 110 return -ENOMEM; 111 112 refcount_set(&f->refcnt, 1); 113 init_completion(&f->completion); 114 return 0; 115 } 116 EXPORT_SYMBOL(inet_frags_init); 117 118 void inet_frags_fini(struct inet_frags *f) 119 { 120 if (refcount_dec_and_test(&f->refcnt)) 121 complete(&f->completion); 122 123 wait_for_completion(&f->completion); 124 125 kmem_cache_destroy(f->frags_cachep); 126 f->frags_cachep = NULL; 127 } 128 EXPORT_SYMBOL(inet_frags_fini); 129 130 /* called from rhashtable_free_and_destroy() at netns_frags dismantle */ 131 static void inet_frags_free_cb(void *ptr, void *arg) 132 { 133 struct inet_frag_queue *fq = ptr; 134 int count; 135 136 count = timer_delete_sync(&fq->timer) ? 1 : 0; 137 138 spin_lock_bh(&fq->lock); 139 fq->flags |= INET_FRAG_DROP; 140 if (!(fq->flags & INET_FRAG_COMPLETE)) { 141 fq->flags |= INET_FRAG_COMPLETE; 142 count++; 143 } else if (fq->flags & INET_FRAG_HASH_DEAD) { 144 count++; 145 } 146 spin_unlock_bh(&fq->lock); 147 148 inet_frag_putn(fq, count); 149 } 150 151 static LLIST_HEAD(fqdir_free_list); 152 153 static void fqdir_free_fn(struct work_struct *work) 154 { 155 struct llist_node *kill_list; 156 struct fqdir *fqdir, *tmp; 157 struct inet_frags *f; 158 159 /* Atomically snapshot the list of fqdirs to free */ 160 kill_list = llist_del_all(&fqdir_free_list); 161 162 /* We need to make sure all ongoing call_rcu(..., inet_frag_destroy_rcu) 163 * have completed, since they need to dereference fqdir. 164 * Would it not be nice to have kfree_rcu_barrier() ? :) 165 */ 166 rcu_barrier(); 167 168 llist_for_each_entry_safe(fqdir, tmp, kill_list, free_list) { 169 f = fqdir->f; 170 if (refcount_dec_and_test(&f->refcnt)) 171 complete(&f->completion); 172 173 kfree(fqdir); 174 } 175 } 176 177 static DECLARE_DELAYED_WORK(fqdir_free_work, fqdir_free_fn); 178 179 static void fqdir_work_fn(struct work_struct *work) 180 { 181 struct fqdir *fqdir = container_of(work, struct fqdir, destroy_work); 182 183 rhashtable_free_and_destroy(&fqdir->rhashtable, inet_frags_free_cb, NULL); 184 185 if (llist_add(&fqdir->free_list, &fqdir_free_list)) 186 queue_delayed_work(system_percpu_wq, &fqdir_free_work, HZ); 187 } 188 189 int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net) 190 { 191 struct fqdir *fqdir = kzalloc_obj(*fqdir); 192 int res; 193 194 if (!fqdir) 195 return -ENOMEM; 196 fqdir->f = f; 197 fqdir->net = net; 198 res = rhashtable_init(&fqdir->rhashtable, &fqdir->f->rhash_params); 199 if (res < 0) { 200 kfree(fqdir); 201 return res; 202 } 203 refcount_inc(&f->refcnt); 204 *fqdirp = fqdir; 205 return 0; 206 } 207 EXPORT_SYMBOL(fqdir_init); 208 209 static struct workqueue_struct *inet_frag_wq; 210 211 static int __init inet_frag_wq_init(void) 212 { 213 inet_frag_wq = create_workqueue("inet_frag_wq"); 214 if (!inet_frag_wq) 215 panic("Could not create inet frag workq"); 216 return 0; 217 } 218 219 pure_initcall(inet_frag_wq_init); 220 221 void fqdir_pre_exit(struct fqdir *fqdir) 222 { 223 struct inet_frag_queue *fq; 224 struct rhashtable_iter hti; 225 226 /* Prevent creation of new frags. 227 * Pairs with READ_ONCE() in inet_frag_find(). 228 */ 229 WRITE_ONCE(fqdir->high_thresh, 0); 230 231 /* Pairs with READ_ONCE() in inet_frag_kill(), ip_expire() 232 * and ip6frag_expire_frag_queue(). 233 */ 234 WRITE_ONCE(fqdir->dead, true); 235 236 rhashtable_walk_enter(&fqdir->rhashtable, &hti); 237 rhashtable_walk_start(&hti); 238 239 while ((fq = rhashtable_walk_next(&hti))) { 240 if (IS_ERR(fq)) { 241 if (PTR_ERR(fq) != -EAGAIN) 242 break; 243 continue; 244 } 245 spin_lock_bh(&fq->lock); 246 if (!(fq->flags & INET_FRAG_COMPLETE)) 247 inet_frag_queue_flush(fq, 0); 248 spin_unlock_bh(&fq->lock); 249 } 250 251 rhashtable_walk_stop(&hti); 252 rhashtable_walk_exit(&hti); 253 } 254 EXPORT_SYMBOL(fqdir_pre_exit); 255 256 void fqdir_exit(struct fqdir *fqdir) 257 { 258 INIT_WORK(&fqdir->destroy_work, fqdir_work_fn); 259 queue_work(inet_frag_wq, &fqdir->destroy_work); 260 } 261 EXPORT_SYMBOL(fqdir_exit); 262 263 void inet_frag_kill(struct inet_frag_queue *fq, int *refs) 264 { 265 if (timer_delete(&fq->timer)) 266 (*refs)++; 267 268 if (!(fq->flags & INET_FRAG_COMPLETE)) { 269 struct fqdir *fqdir = fq->fqdir; 270 271 fq->flags |= INET_FRAG_COMPLETE; 272 rcu_read_lock(); 273 /* The RCU read lock provides a memory barrier 274 * guaranteeing that if fqdir->dead is false then 275 * the hash table destruction will not start until 276 * after we unlock. Paired with fqdir_pre_exit(). 277 */ 278 if (!READ_ONCE(fqdir->dead)) { 279 rhashtable_remove_fast(&fqdir->rhashtable, &fq->node, 280 fqdir->f->rhash_params); 281 (*refs)++; 282 } else { 283 fq->flags |= INET_FRAG_HASH_DEAD; 284 } 285 rcu_read_unlock(); 286 } 287 } 288 EXPORT_SYMBOL(inet_frag_kill); 289 290 static void inet_frag_destroy_rcu(struct rcu_head *head) 291 { 292 struct inet_frag_queue *q = container_of(head, struct inet_frag_queue, 293 rcu); 294 struct inet_frags *f = q->fqdir->f; 295 296 if (f->destructor) 297 f->destructor(q); 298 kmem_cache_free(f->frags_cachep, q); 299 } 300 301 static unsigned int 302 inet_frag_rbtree_purge(struct rb_root *root, enum skb_drop_reason reason) 303 { 304 struct rb_node *p = rb_first(root); 305 unsigned int sum = 0; 306 307 while (p) { 308 struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode); 309 310 p = rb_next(p); 311 rb_erase(&skb->rbnode, root); 312 while (skb) { 313 struct sk_buff *next = FRAG_CB(skb)->next_frag; 314 315 sum += skb->truesize; 316 kfree_skb_reason(skb, reason); 317 skb = next; 318 } 319 } 320 return sum; 321 } 322 323 void inet_frag_queue_flush(struct inet_frag_queue *q, 324 enum skb_drop_reason reason) 325 { 326 unsigned int sum; 327 328 reason = reason ?: SKB_DROP_REASON_FRAG_REASM_TIMEOUT; 329 sum = inet_frag_rbtree_purge(&q->rb_fragments, reason); 330 sub_frag_mem_limit(q->fqdir, sum); 331 q->rb_fragments = RB_ROOT; 332 q->fragments_tail = NULL; 333 q->last_run_head = NULL; 334 } 335 EXPORT_SYMBOL(inet_frag_queue_flush); 336 337 void inet_frag_destroy(struct inet_frag_queue *q) 338 { 339 unsigned int sum, sum_truesize = 0; 340 enum skb_drop_reason reason; 341 struct inet_frags *f; 342 struct fqdir *fqdir; 343 344 WARN_ON(!(q->flags & INET_FRAG_COMPLETE)); 345 reason = (q->flags & INET_FRAG_DROP) ? 346 SKB_DROP_REASON_FRAG_REASM_TIMEOUT : 347 SKB_CONSUMED; 348 WARN_ON(timer_delete(&q->timer) != 0); 349 350 /* Release all fragment data. */ 351 fqdir = q->fqdir; 352 f = fqdir->f; 353 sum_truesize = inet_frag_rbtree_purge(&q->rb_fragments, reason); 354 sum = sum_truesize + f->qsize; 355 356 call_rcu(&q->rcu, inet_frag_destroy_rcu); 357 358 sub_frag_mem_limit(fqdir, sum); 359 } 360 EXPORT_SYMBOL(inet_frag_destroy); 361 362 static struct inet_frag_queue *inet_frag_alloc(struct fqdir *fqdir, 363 struct inet_frags *f, 364 void *arg) 365 { 366 struct inet_frag_queue *q; 367 368 q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC); 369 if (!q) 370 return NULL; 371 372 q->fqdir = fqdir; 373 f->constructor(q, arg); 374 add_frag_mem_limit(fqdir, f->qsize); 375 376 timer_setup(&q->timer, f->frag_expire, 0); 377 spin_lock_init(&q->lock); 378 /* One reference for the timer, one for the hash table. 379 * We never take any extra references, only decrement this field. 380 */ 381 refcount_set(&q->refcnt, 2); 382 383 return q; 384 } 385 386 static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, 387 void *arg, 388 struct inet_frag_queue **prev) 389 { 390 struct inet_frags *f = fqdir->f; 391 struct inet_frag_queue *q; 392 393 q = inet_frag_alloc(fqdir, f, arg); 394 if (!q) { 395 *prev = ERR_PTR(-ENOMEM); 396 return NULL; 397 } 398 mod_timer(&q->timer, jiffies + fqdir->timeout); 399 400 *prev = rhashtable_lookup_get_insert_key(&fqdir->rhashtable, &q->key, 401 &q->node, f->rhash_params); 402 if (*prev) { 403 /* We could not insert in the hash table, 404 * we need to cancel what inet_frag_alloc() 405 * anticipated. 406 */ 407 int refs = 1; 408 409 q->flags |= INET_FRAG_COMPLETE; 410 inet_frag_kill(q, &refs); 411 inet_frag_putn(q, refs); 412 return NULL; 413 } 414 return q; 415 } 416 417 struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key) 418 { 419 /* This pairs with WRITE_ONCE() in fqdir_pre_exit(). */ 420 long high_thresh = READ_ONCE(fqdir->high_thresh); 421 struct inet_frag_queue *fq = NULL, *prev; 422 423 if (!high_thresh || frag_mem_limit(fqdir) > high_thresh) 424 return NULL; 425 426 prev = rhashtable_lookup(&fqdir->rhashtable, key, fqdir->f->rhash_params); 427 if (!prev) 428 fq = inet_frag_create(fqdir, key, &prev); 429 if (!IS_ERR_OR_NULL(prev)) 430 fq = prev; 431 return fq; 432 } 433 EXPORT_SYMBOL(inet_frag_find); 434 435 int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb, 436 int offset, int end) 437 { 438 struct sk_buff *last = q->fragments_tail; 439 440 /* RFC5722, Section 4, amended by Errata ID : 3089 441 * When reassembling an IPv6 datagram, if 442 * one or more its constituent fragments is determined to be an 443 * overlapping fragment, the entire datagram (and any constituent 444 * fragments) MUST be silently discarded. 445 * 446 * Duplicates, however, should be ignored (i.e. skb dropped, but the 447 * queue/fragments kept for later reassembly). 448 */ 449 if (!last) 450 fragrun_create(q, skb); /* First fragment. */ 451 else if (FRAG_CB(last)->ip_defrag_offset + last->len < end) { 452 /* This is the common case: skb goes to the end. */ 453 /* Detect and discard overlaps. */ 454 if (offset < FRAG_CB(last)->ip_defrag_offset + last->len) 455 return IPFRAG_OVERLAP; 456 if (offset == FRAG_CB(last)->ip_defrag_offset + last->len) 457 fragrun_append_to_last(q, skb); 458 else 459 fragrun_create(q, skb); 460 } else { 461 /* Binary search. Note that skb can become the first fragment, 462 * but not the last (covered above). 463 */ 464 struct rb_node **rbn, *parent; 465 466 rbn = &q->rb_fragments.rb_node; 467 do { 468 struct sk_buff *curr; 469 int curr_run_end; 470 471 parent = *rbn; 472 curr = rb_to_skb(parent); 473 curr_run_end = FRAG_CB(curr)->ip_defrag_offset + 474 FRAG_CB(curr)->frag_run_len; 475 if (end <= FRAG_CB(curr)->ip_defrag_offset) 476 rbn = &parent->rb_left; 477 else if (offset >= curr_run_end) 478 rbn = &parent->rb_right; 479 else if (offset >= FRAG_CB(curr)->ip_defrag_offset && 480 end <= curr_run_end) 481 return IPFRAG_DUP; 482 else 483 return IPFRAG_OVERLAP; 484 } while (*rbn); 485 /* Here we have parent properly set, and rbn pointing to 486 * one of its NULL left/right children. Insert skb. 487 */ 488 fragcb_clear(skb); 489 rb_link_node(&skb->rbnode, parent, rbn); 490 rb_insert_color(&skb->rbnode, &q->rb_fragments); 491 } 492 493 FRAG_CB(skb)->ip_defrag_offset = offset; 494 if (offset) 495 nf_reset_ct(skb); 496 497 return IPFRAG_OK; 498 } 499 EXPORT_SYMBOL(inet_frag_queue_insert); 500 501 void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb, 502 struct sk_buff *parent) 503 { 504 struct sk_buff *fp, *head = skb_rb_first(&q->rb_fragments); 505 void (*destructor)(struct sk_buff *); 506 unsigned int orig_truesize = 0; 507 struct sk_buff **nextp = NULL; 508 struct sock *sk = skb->sk; 509 int delta; 510 511 if (sk && is_skb_wmem(skb)) { 512 /* TX: skb->sk might have been passed as argument to 513 * dst->output and must remain valid until tx completes. 514 * 515 * Move sk to reassembled skb and fix up wmem accounting. 516 */ 517 orig_truesize = skb->truesize; 518 destructor = skb->destructor; 519 } 520 521 if (head != skb) { 522 fp = skb_clone(skb, GFP_ATOMIC); 523 if (!fp) { 524 head = skb; 525 goto out_restore_sk; 526 } 527 FRAG_CB(fp)->next_frag = FRAG_CB(skb)->next_frag; 528 if (RB_EMPTY_NODE(&skb->rbnode)) 529 FRAG_CB(parent)->next_frag = fp; 530 else 531 rb_replace_node(&skb->rbnode, &fp->rbnode, 532 &q->rb_fragments); 533 if (q->fragments_tail == skb) 534 q->fragments_tail = fp; 535 536 if (orig_truesize) { 537 /* prevent skb_morph from releasing sk */ 538 skb->sk = NULL; 539 skb->destructor = NULL; 540 } 541 skb_morph(skb, head); 542 FRAG_CB(skb)->next_frag = FRAG_CB(head)->next_frag; 543 rb_replace_node(&head->rbnode, &skb->rbnode, 544 &q->rb_fragments); 545 consume_skb(head); 546 head = skb; 547 } 548 WARN_ON(FRAG_CB(head)->ip_defrag_offset != 0); 549 550 delta = -head->truesize; 551 552 /* Head of list must not be cloned. */ 553 if (skb_unclone(head, GFP_ATOMIC)) 554 goto out_restore_sk; 555 556 delta += head->truesize; 557 if (delta) 558 add_frag_mem_limit(q->fqdir, delta); 559 560 /* If the first fragment is fragmented itself, we split 561 * it to two chunks: the first with data and paged part 562 * and the second, holding only fragments. 563 */ 564 if (skb_has_frag_list(head)) { 565 struct sk_buff *clone; 566 int i, plen = 0; 567 568 clone = alloc_skb(0, GFP_ATOMIC); 569 if (!clone) 570 goto out_restore_sk; 571 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 572 skb_frag_list_init(head); 573 for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 574 plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 575 clone->data_len = head->data_len - plen; 576 clone->len = clone->data_len; 577 head->truesize += clone->truesize; 578 clone->csum = 0; 579 clone->ip_summed = head->ip_summed; 580 add_frag_mem_limit(q->fqdir, clone->truesize); 581 skb_shinfo(head)->frag_list = clone; 582 nextp = &clone->next; 583 } else { 584 nextp = &skb_shinfo(head)->frag_list; 585 } 586 587 out_restore_sk: 588 if (orig_truesize) { 589 int ts_delta = head->truesize - orig_truesize; 590 591 /* if this reassembled skb is fragmented later, 592 * fraglist skbs will get skb->sk assigned from head->sk, 593 * and each frag skb will be released via sock_wfree. 594 * 595 * Update sk_wmem_alloc. 596 */ 597 head->sk = sk; 598 head->destructor = destructor; 599 refcount_add(ts_delta, &sk->sk_wmem_alloc); 600 } 601 602 return nextp; 603 } 604 EXPORT_SYMBOL(inet_frag_reasm_prepare); 605 606 void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head, 607 void *reasm_data, bool try_coalesce) 608 { 609 struct sock *sk = is_skb_wmem(head) ? head->sk : NULL; 610 const unsigned int head_truesize = head->truesize; 611 struct sk_buff **nextp = reasm_data; 612 struct rb_node *rbn; 613 struct sk_buff *fp; 614 int sum_truesize; 615 616 skb_push(head, head->data - skb_network_header(head)); 617 618 /* Traverse the tree in order, to build frag_list. */ 619 fp = FRAG_CB(head)->next_frag; 620 rbn = rb_next(&head->rbnode); 621 rb_erase(&head->rbnode, &q->rb_fragments); 622 623 sum_truesize = head->truesize; 624 while (rbn || fp) { 625 /* fp points to the next sk_buff in the current run; 626 * rbn points to the next run. 627 */ 628 /* Go through the current run. */ 629 while (fp) { 630 struct sk_buff *next_frag = FRAG_CB(fp)->next_frag; 631 bool stolen; 632 int delta; 633 634 sum_truesize += fp->truesize; 635 if (head->ip_summed != fp->ip_summed) 636 head->ip_summed = CHECKSUM_NONE; 637 else if (head->ip_summed == CHECKSUM_COMPLETE) 638 head->csum = csum_add(head->csum, fp->csum); 639 640 if (try_coalesce && skb_try_coalesce(head, fp, &stolen, 641 &delta)) { 642 kfree_skb_partial(fp, stolen); 643 } else { 644 fp->prev = NULL; 645 memset(&fp->rbnode, 0, sizeof(fp->rbnode)); 646 fp->sk = NULL; 647 648 head->data_len += fp->len; 649 head->len += fp->len; 650 head->truesize += fp->truesize; 651 652 *nextp = fp; 653 nextp = &fp->next; 654 } 655 656 fp = next_frag; 657 } 658 /* Move to the next run. */ 659 if (rbn) { 660 struct rb_node *rbnext = rb_next(rbn); 661 662 fp = rb_to_skb(rbn); 663 rb_erase(rbn, &q->rb_fragments); 664 rbn = rbnext; 665 } 666 } 667 sub_frag_mem_limit(q->fqdir, sum_truesize); 668 669 *nextp = NULL; 670 skb_mark_not_on_list(head); 671 head->prev = NULL; 672 head->tstamp = q->stamp; 673 head->tstamp_type = q->tstamp_type; 674 675 if (sk) 676 refcount_add(sum_truesize - head_truesize, &sk->sk_wmem_alloc); 677 } 678 EXPORT_SYMBOL(inet_frag_reasm_finish); 679 680 struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q) 681 { 682 struct sk_buff *head, *skb; 683 684 head = skb_rb_first(&q->rb_fragments); 685 if (!head) 686 return NULL; 687 skb = FRAG_CB(head)->next_frag; 688 if (skb) 689 rb_replace_node(&head->rbnode, &skb->rbnode, 690 &q->rb_fragments); 691 else 692 rb_erase(&head->rbnode, &q->rb_fragments); 693 memset(&head->rbnode, 0, sizeof(head->rbnode)); 694 barrier(); 695 696 if (head == q->fragments_tail) 697 q->fragments_tail = NULL; 698 699 sub_frag_mem_limit(q->fqdir, head->truesize); 700 701 return head; 702 } 703 EXPORT_SYMBOL(inet_frag_pull_head); 704