1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * The IP fragmentation functionality.
8 *
9 * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG>
10 * Alan Cox <alan@lxorguk.ukuu.org.uk>
11 *
12 * Fixes:
13 * Alan Cox : Split from ip.c , see ip_input.c for history.
14 * David S. Miller : Begin massive cleanup...
15 * Andi Kleen : Add sysctls.
16 * xxxx : Overlapfrag bug.
17 * Ultima : ip_expire() kernel panic.
18 * Bill Hawes : Frag accounting and evictor fixes.
19 * John McDonald : 0 length frag bug.
20 * Alexey Kuznetsov: SMP races, threading, cleanup.
21 * Patrick McHardy : LRU queue of frag heads for evictor.
22 */
23
24 #define pr_fmt(fmt) "IPv4: " fmt
25
26 #include <linux/compiler.h>
27 #include <linux/module.h>
28 #include <linux/types.h>
29 #include <linux/mm.h>
30 #include <linux/jiffies.h>
31 #include <linux/skbuff.h>
32 #include <linux/list.h>
33 #include <linux/ip.h>
34 #include <linux/icmp.h>
35 #include <linux/netdevice.h>
36 #include <linux/jhash.h>
37 #include <linux/random.h>
38 #include <linux/slab.h>
39 #include <net/route.h>
40 #include <net/dst.h>
41 #include <net/sock.h>
42 #include <net/ip.h>
43 #include <net/icmp.h>
44 #include <net/checksum.h>
45 #include <net/inetpeer.h>
46 #include <net/inet_frag.h>
47 #include <linux/tcp.h>
48 #include <linux/udp.h>
49 #include <linux/inet.h>
50 #include <linux/netfilter_ipv4.h>
51 #include <net/inet_ecn.h>
52 #include <net/l3mdev.h>
53
54 /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6
55 * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c
56 * as well. Or notify me, at least. --ANK
57 */
58 static const char ip_frag_cache_name[] = "ip4-frags";
59
60 /* Describe an entry in the "incomplete datagrams" queue. */
61 struct ipq {
62 struct inet_frag_queue q;
63
64 u8 ecn; /* RFC3168 support */
65 u16 max_df_size; /* largest frag with DF set seen */
66 int iif;
67 unsigned int rid;
68 struct inet_peer *peer;
69 };
70
ip4_frag_ecn(u8 tos)71 static u8 ip4_frag_ecn(u8 tos)
72 {
73 return 1 << (tos & INET_ECN_MASK);
74 }
75
76 static struct inet_frags ip4_frags;
77
78 static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
79 struct sk_buff *prev_tail, struct net_device *dev);
80
81
ip4_frag_init(struct inet_frag_queue * q,const void * a)82 static void ip4_frag_init(struct inet_frag_queue *q, const void *a)
83 {
84 struct ipq *qp = container_of(q, struct ipq, q);
85 struct net *net = q->fqdir->net;
86
87 const struct frag_v4_compare_key *key = a;
88
89 q->key.v4 = *key;
90 qp->ecn = 0;
91 qp->peer = q->fqdir->max_dist ?
92 inet_getpeer_v4(net->ipv4.peers, key->saddr, key->vif, 1) :
93 NULL;
94 }
95
ip4_frag_free(struct inet_frag_queue * q)96 static void ip4_frag_free(struct inet_frag_queue *q)
97 {
98 struct ipq *qp;
99
100 qp = container_of(q, struct ipq, q);
101 if (qp->peer)
102 inet_putpeer(qp->peer);
103 }
104
105
106 /* Destruction primitives. */
107
ipq_put(struct ipq * ipq)108 static void ipq_put(struct ipq *ipq)
109 {
110 inet_frag_put(&ipq->q);
111 }
112
113 /* Kill ipq entry. It is not destroyed immediately,
114 * because caller (and someone more) holds reference count.
115 */
ipq_kill(struct ipq * ipq)116 static void ipq_kill(struct ipq *ipq)
117 {
118 inet_frag_kill(&ipq->q);
119 }
120
frag_expire_skip_icmp(u32 user)121 static bool frag_expire_skip_icmp(u32 user)
122 {
123 return user == IP_DEFRAG_AF_PACKET ||
124 ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_IN,
125 __IP_DEFRAG_CONNTRACK_IN_END) ||
126 ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_BRIDGE_IN,
127 __IP_DEFRAG_CONNTRACK_BRIDGE_IN);
128 }
129
130 /*
131 * Oops, a fragment queue timed out. Kill it and send an ICMP reply.
132 */
ip_expire(struct timer_list * t)133 static void ip_expire(struct timer_list *t)
134 {
135 struct inet_frag_queue *frag = from_timer(frag, t, timer);
136 const struct iphdr *iph;
137 struct sk_buff *head = NULL;
138 struct net *net;
139 struct ipq *qp;
140 int err;
141
142 qp = container_of(frag, struct ipq, q);
143 net = qp->q.fqdir->net;
144
145 rcu_read_lock();
146
147 if (qp->q.fqdir->dead)
148 goto out_rcu_unlock;
149
150 spin_lock(&qp->q.lock);
151
152 if (qp->q.flags & INET_FRAG_COMPLETE)
153 goto out;
154
155 ipq_kill(qp);
156 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
157 __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT);
158
159 if (!(qp->q.flags & INET_FRAG_FIRST_IN))
160 goto out;
161
162 /* sk_buff::dev and sk_buff::rbnode are unionized. So we
163 * pull the head out of the tree in order to be able to
164 * deal with head->dev.
165 */
166 head = inet_frag_pull_head(&qp->q);
167 if (!head)
168 goto out;
169 head->dev = dev_get_by_index_rcu(net, qp->iif);
170 if (!head->dev)
171 goto out;
172
173
174 /* skb has no dst, perform route lookup again */
175 iph = ip_hdr(head);
176 err = ip_route_input_noref(head, iph->daddr, iph->saddr,
177 iph->tos, head->dev);
178 if (err)
179 goto out;
180
181 /* Only an end host needs to send an ICMP
182 * "Fragment Reassembly Timeout" message, per RFC792.
183 */
184 if (frag_expire_skip_icmp(qp->q.key.v4.user) &&
185 (skb_rtable(head)->rt_type != RTN_LOCAL))
186 goto out;
187
188 spin_unlock(&qp->q.lock);
189 icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
190 goto out_rcu_unlock;
191
192 out:
193 spin_unlock(&qp->q.lock);
194 out_rcu_unlock:
195 rcu_read_unlock();
196 kfree_skb(head);
197 ipq_put(qp);
198 }
199
200 /* Find the correct entry in the "incomplete datagrams" queue for
201 * this IP datagram, and create new one, if nothing is found.
202 */
ip_find(struct net * net,struct iphdr * iph,u32 user,int vif)203 static struct ipq *ip_find(struct net *net, struct iphdr *iph,
204 u32 user, int vif)
205 {
206 struct frag_v4_compare_key key = {
207 .saddr = iph->saddr,
208 .daddr = iph->daddr,
209 .user = user,
210 .vif = vif,
211 .id = iph->id,
212 .protocol = iph->protocol,
213 };
214 struct inet_frag_queue *q;
215
216 q = inet_frag_find(net->ipv4.fqdir, &key);
217 if (!q)
218 return NULL;
219
220 return container_of(q, struct ipq, q);
221 }
222
223 /* Is the fragment too far ahead to be part of ipq? */
ip_frag_too_far(struct ipq * qp)224 static int ip_frag_too_far(struct ipq *qp)
225 {
226 struct inet_peer *peer = qp->peer;
227 unsigned int max = qp->q.fqdir->max_dist;
228 unsigned int start, end;
229
230 int rc;
231
232 if (!peer || !max)
233 return 0;
234
235 start = qp->rid;
236 end = atomic_inc_return(&peer->rid);
237 qp->rid = end;
238
239 rc = qp->q.fragments_tail && (end - start) > max;
240
241 if (rc)
242 __IP_INC_STATS(qp->q.fqdir->net, IPSTATS_MIB_REASMFAILS);
243
244 return rc;
245 }
246
ip_frag_reinit(struct ipq * qp)247 static int ip_frag_reinit(struct ipq *qp)
248 {
249 unsigned int sum_truesize = 0;
250
251 if (!mod_timer(&qp->q.timer, jiffies + qp->q.fqdir->timeout)) {
252 refcount_inc(&qp->q.refcnt);
253 return -ETIMEDOUT;
254 }
255
256 sum_truesize = inet_frag_rbtree_purge(&qp->q.rb_fragments);
257 sub_frag_mem_limit(qp->q.fqdir, sum_truesize);
258
259 qp->q.flags = 0;
260 qp->q.len = 0;
261 qp->q.meat = 0;
262 qp->q.rb_fragments = RB_ROOT;
263 qp->q.fragments_tail = NULL;
264 qp->q.last_run_head = NULL;
265 qp->iif = 0;
266 qp->ecn = 0;
267
268 return 0;
269 }
270
271 /* Add new segment to existing queue. */
ip_frag_queue(struct ipq * qp,struct sk_buff * skb)272 static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
273 {
274 struct net *net = qp->q.fqdir->net;
275 int ihl, end, flags, offset;
276 struct sk_buff *prev_tail;
277 struct net_device *dev;
278 unsigned int fragsize;
279 int err = -ENOENT;
280 u8 ecn;
281
282 if (qp->q.flags & INET_FRAG_COMPLETE)
283 goto err;
284
285 if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
286 unlikely(ip_frag_too_far(qp)) &&
287 unlikely(err = ip_frag_reinit(qp))) {
288 ipq_kill(qp);
289 goto err;
290 }
291
292 ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
293 offset = ntohs(ip_hdr(skb)->frag_off);
294 flags = offset & ~IP_OFFSET;
295 offset &= IP_OFFSET;
296 offset <<= 3; /* offset is in 8-byte chunks */
297 ihl = ip_hdrlen(skb);
298
299 /* Determine the position of this fragment. */
300 end = offset + skb->len - skb_network_offset(skb) - ihl;
301 err = -EINVAL;
302
303 /* Is this the final fragment? */
304 if ((flags & IP_MF) == 0) {
305 /* If we already have some bits beyond end
306 * or have different end, the segment is corrupted.
307 */
308 if (end < qp->q.len ||
309 ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len))
310 goto discard_qp;
311 qp->q.flags |= INET_FRAG_LAST_IN;
312 qp->q.len = end;
313 } else {
314 if (end&7) {
315 end &= ~7;
316 if (skb->ip_summed != CHECKSUM_UNNECESSARY)
317 skb->ip_summed = CHECKSUM_NONE;
318 }
319 if (end > qp->q.len) {
320 /* Some bits beyond end -> corruption. */
321 if (qp->q.flags & INET_FRAG_LAST_IN)
322 goto discard_qp;
323 qp->q.len = end;
324 }
325 }
326 if (end == offset)
327 goto discard_qp;
328
329 err = -ENOMEM;
330 if (!pskb_pull(skb, skb_network_offset(skb) + ihl))
331 goto discard_qp;
332
333 err = pskb_trim_rcsum(skb, end - offset);
334 if (err)
335 goto discard_qp;
336
337 /* Note : skb->rbnode and skb->dev share the same location. */
338 dev = skb->dev;
339 /* Makes sure compiler wont do silly aliasing games */
340 barrier();
341
342 prev_tail = qp->q.fragments_tail;
343 err = inet_frag_queue_insert(&qp->q, skb, offset, end);
344 if (err)
345 goto insert_error;
346
347 if (dev)
348 qp->iif = dev->ifindex;
349
350 qp->q.stamp = skb->tstamp;
351 qp->q.meat += skb->len;
352 qp->ecn |= ecn;
353 add_frag_mem_limit(qp->q.fqdir, skb->truesize);
354 if (offset == 0)
355 qp->q.flags |= INET_FRAG_FIRST_IN;
356
357 fragsize = skb->len + ihl;
358
359 if (fragsize > qp->q.max_size)
360 qp->q.max_size = fragsize;
361
362 if (ip_hdr(skb)->frag_off & htons(IP_DF) &&
363 fragsize > qp->max_df_size)
364 qp->max_df_size = fragsize;
365
366 if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
367 qp->q.meat == qp->q.len) {
368 unsigned long orefdst = skb->_skb_refdst;
369
370 skb->_skb_refdst = 0UL;
371 err = ip_frag_reasm(qp, skb, prev_tail, dev);
372 skb->_skb_refdst = orefdst;
373 if (err)
374 inet_frag_kill(&qp->q);
375 return err;
376 }
377
378 skb_dst_drop(skb);
379 return -EINPROGRESS;
380
381 insert_error:
382 if (err == IPFRAG_DUP) {
383 kfree_skb(skb);
384 return -EINVAL;
385 }
386 err = -EINVAL;
387 __IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
388 discard_qp:
389 inet_frag_kill(&qp->q);
390 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
391 err:
392 kfree_skb(skb);
393 return err;
394 }
395
ip_frag_coalesce_ok(const struct ipq * qp)396 static bool ip_frag_coalesce_ok(const struct ipq *qp)
397 {
398 return qp->q.key.v4.user == IP_DEFRAG_LOCAL_DELIVER;
399 }
400
401 /* Build a new IP datagram from all its fragments. */
ip_frag_reasm(struct ipq * qp,struct sk_buff * skb,struct sk_buff * prev_tail,struct net_device * dev)402 static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
403 struct sk_buff *prev_tail, struct net_device *dev)
404 {
405 struct net *net = qp->q.fqdir->net;
406 struct iphdr *iph;
407 void *reasm_data;
408 int len, err;
409 u8 ecn;
410
411 ipq_kill(qp);
412
413 ecn = ip_frag_ecn_table[qp->ecn];
414 if (unlikely(ecn == 0xff)) {
415 err = -EINVAL;
416 goto out_fail;
417 }
418
419 /* Make the one we just received the head. */
420 reasm_data = inet_frag_reasm_prepare(&qp->q, skb, prev_tail);
421 if (!reasm_data)
422 goto out_nomem;
423
424 len = ip_hdrlen(skb) + qp->q.len;
425 err = -E2BIG;
426 if (len > 65535)
427 goto out_oversize;
428
429 inet_frag_reasm_finish(&qp->q, skb, reasm_data,
430 ip_frag_coalesce_ok(qp));
431
432 skb->dev = dev;
433 IPCB(skb)->frag_max_size = max(qp->max_df_size, qp->q.max_size);
434
435 iph = ip_hdr(skb);
436 iph->tot_len = htons(len);
437 iph->tos |= ecn;
438
439 /* When we set IP_DF on a refragmented skb we must also force a
440 * call to ip_fragment to avoid forwarding a DF-skb of size s while
441 * original sender only sent fragments of size f (where f < s).
442 *
443 * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest
444 * frag seen to avoid sending tiny DF-fragments in case skb was built
445 * from one very small df-fragment and one large non-df frag.
446 */
447 if (qp->max_df_size == qp->q.max_size) {
448 IPCB(skb)->flags |= IPSKB_FRAG_PMTU;
449 iph->frag_off = htons(IP_DF);
450 } else {
451 iph->frag_off = 0;
452 }
453
454 ip_send_check(iph);
455
456 __IP_INC_STATS(net, IPSTATS_MIB_REASMOKS);
457 qp->q.rb_fragments = RB_ROOT;
458 qp->q.fragments_tail = NULL;
459 qp->q.last_run_head = NULL;
460 return 0;
461
462 out_nomem:
463 net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp);
464 err = -ENOMEM;
465 goto out_fail;
466 out_oversize:
467 net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->q.key.v4.saddr);
468 out_fail:
469 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
470 return err;
471 }
472
473 /* Process an incoming IP datagram fragment. */
ip_defrag(struct net * net,struct sk_buff * skb,u32 user)474 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user)
475 {
476 struct net_device *dev = skb->dev ? : skb_dst(skb)->dev;
477 int vif = l3mdev_master_ifindex_rcu(dev);
478 struct ipq *qp;
479
480 __IP_INC_STATS(net, IPSTATS_MIB_REASMREQDS);
481 skb_orphan(skb);
482
483 /* Lookup (or create) queue header */
484 qp = ip_find(net, ip_hdr(skb), user, vif);
485 if (qp) {
486 int ret;
487
488 spin_lock(&qp->q.lock);
489
490 ret = ip_frag_queue(qp, skb);
491
492 spin_unlock(&qp->q.lock);
493 ipq_put(qp);
494 return ret;
495 }
496
497 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
498 kfree_skb(skb);
499 return -ENOMEM;
500 }
501 EXPORT_SYMBOL(ip_defrag);
502
ip_check_defrag(struct net * net,struct sk_buff * skb,u32 user)503 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
504 {
505 struct iphdr iph;
506 int netoff;
507 u32 len;
508
509 if (skb->protocol != htons(ETH_P_IP))
510 return skb;
511
512 netoff = skb_network_offset(skb);
513
514 if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0)
515 return skb;
516
517 if (iph.ihl < 5 || iph.version != 4)
518 return skb;
519
520 len = ntohs(iph.tot_len);
521 if (skb->len < netoff + len || len < (iph.ihl * 4))
522 return skb;
523
524 if (ip_is_fragment(&iph)) {
525 skb = skb_share_check(skb, GFP_ATOMIC);
526 if (skb) {
527 if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) {
528 kfree_skb(skb);
529 return NULL;
530 }
531 if (pskb_trim_rcsum(skb, netoff + len)) {
532 kfree_skb(skb);
533 return NULL;
534 }
535 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
536 if (ip_defrag(net, skb, user))
537 return NULL;
538 skb_clear_hash(skb);
539 }
540 }
541 return skb;
542 }
543 EXPORT_SYMBOL(ip_check_defrag);
544
545 #ifdef CONFIG_SYSCTL
546 static int dist_min;
547
548 static struct ctl_table ip4_frags_ns_ctl_table[] = {
549 {
550 .procname = "ipfrag_high_thresh",
551 .maxlen = sizeof(unsigned long),
552 .mode = 0644,
553 .proc_handler = proc_doulongvec_minmax,
554 },
555 {
556 .procname = "ipfrag_low_thresh",
557 .maxlen = sizeof(unsigned long),
558 .mode = 0644,
559 .proc_handler = proc_doulongvec_minmax,
560 },
561 {
562 .procname = "ipfrag_time",
563 .maxlen = sizeof(int),
564 .mode = 0644,
565 .proc_handler = proc_dointvec_jiffies,
566 },
567 {
568 .procname = "ipfrag_max_dist",
569 .maxlen = sizeof(int),
570 .mode = 0644,
571 .proc_handler = proc_dointvec_minmax,
572 .extra1 = &dist_min,
573 },
574 { }
575 };
576
577 /* secret interval has been deprecated */
578 static int ip4_frags_secret_interval_unused;
579 static struct ctl_table ip4_frags_ctl_table[] = {
580 {
581 .procname = "ipfrag_secret_interval",
582 .data = &ip4_frags_secret_interval_unused,
583 .maxlen = sizeof(int),
584 .mode = 0644,
585 .proc_handler = proc_dointvec_jiffies,
586 },
587 { }
588 };
589
ip4_frags_ns_ctl_register(struct net * net)590 static int __net_init ip4_frags_ns_ctl_register(struct net *net)
591 {
592 struct ctl_table *table;
593 struct ctl_table_header *hdr;
594
595 table = ip4_frags_ns_ctl_table;
596 if (!net_eq(net, &init_net)) {
597 table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL);
598 if (!table)
599 goto err_alloc;
600
601 }
602 table[0].data = &net->ipv4.fqdir->high_thresh;
603 table[0].extra1 = &net->ipv4.fqdir->low_thresh;
604 table[1].data = &net->ipv4.fqdir->low_thresh;
605 table[1].extra2 = &net->ipv4.fqdir->high_thresh;
606 table[2].data = &net->ipv4.fqdir->timeout;
607 table[3].data = &net->ipv4.fqdir->max_dist;
608
609 hdr = register_net_sysctl(net, "net/ipv4", table);
610 if (!hdr)
611 goto err_reg;
612
613 net->ipv4.frags_hdr = hdr;
614 return 0;
615
616 err_reg:
617 if (!net_eq(net, &init_net))
618 kfree(table);
619 err_alloc:
620 return -ENOMEM;
621 }
622
ip4_frags_ns_ctl_unregister(struct net * net)623 static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net)
624 {
625 struct ctl_table *table;
626
627 table = net->ipv4.frags_hdr->ctl_table_arg;
628 unregister_net_sysctl_table(net->ipv4.frags_hdr);
629 kfree(table);
630 }
631
ip4_frags_ctl_register(void)632 static void __init ip4_frags_ctl_register(void)
633 {
634 register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table);
635 }
636 #else
ip4_frags_ns_ctl_register(struct net * net)637 static int ip4_frags_ns_ctl_register(struct net *net)
638 {
639 return 0;
640 }
641
ip4_frags_ns_ctl_unregister(struct net * net)642 static void ip4_frags_ns_ctl_unregister(struct net *net)
643 {
644 }
645
ip4_frags_ctl_register(void)646 static void __init ip4_frags_ctl_register(void)
647 {
648 }
649 #endif
650
ipv4_frags_init_net(struct net * net)651 static int __net_init ipv4_frags_init_net(struct net *net)
652 {
653 int res;
654
655 res = fqdir_init(&net->ipv4.fqdir, &ip4_frags, net);
656 if (res < 0)
657 return res;
658 /* Fragment cache limits.
659 *
660 * The fragment memory accounting code, (tries to) account for
661 * the real memory usage, by measuring both the size of frag
662 * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue))
663 * and the SKB's truesize.
664 *
665 * A 64K fragment consumes 129736 bytes (44*2944)+200
666 * (1500 truesize == 2944, sizeof(struct ipq) == 200)
667 *
668 * We will commit 4MB at one time. Should we cross that limit
669 * we will prune down to 3MB, making room for approx 8 big 64K
670 * fragments 8x128k.
671 */
672 net->ipv4.fqdir->high_thresh = 4 * 1024 * 1024;
673 net->ipv4.fqdir->low_thresh = 3 * 1024 * 1024;
674 /*
675 * Important NOTE! Fragment queue must be destroyed before MSL expires.
676 * RFC791 is wrong proposing to prolongate timer each fragment arrival
677 * by TTL.
678 */
679 net->ipv4.fqdir->timeout = IP_FRAG_TIME;
680
681 net->ipv4.fqdir->max_dist = 64;
682
683 res = ip4_frags_ns_ctl_register(net);
684 if (res < 0)
685 fqdir_exit(net->ipv4.fqdir);
686 return res;
687 }
688
ipv4_frags_pre_exit_net(struct net * net)689 static void __net_exit ipv4_frags_pre_exit_net(struct net *net)
690 {
691 fqdir_pre_exit(net->ipv4.fqdir);
692 }
693
ipv4_frags_exit_net(struct net * net)694 static void __net_exit ipv4_frags_exit_net(struct net *net)
695 {
696 ip4_frags_ns_ctl_unregister(net);
697 fqdir_exit(net->ipv4.fqdir);
698 }
699
700 static struct pernet_operations ip4_frags_ops = {
701 .init = ipv4_frags_init_net,
702 .pre_exit = ipv4_frags_pre_exit_net,
703 .exit = ipv4_frags_exit_net,
704 };
705
706
ip4_key_hashfn(const void * data,u32 len,u32 seed)707 static u32 ip4_key_hashfn(const void *data, u32 len, u32 seed)
708 {
709 return jhash2(data,
710 sizeof(struct frag_v4_compare_key) / sizeof(u32), seed);
711 }
712
ip4_obj_hashfn(const void * data,u32 len,u32 seed)713 static u32 ip4_obj_hashfn(const void *data, u32 len, u32 seed)
714 {
715 const struct inet_frag_queue *fq = data;
716
717 return jhash2((const u32 *)&fq->key.v4,
718 sizeof(struct frag_v4_compare_key) / sizeof(u32), seed);
719 }
720
ip4_obj_cmpfn(struct rhashtable_compare_arg * arg,const void * ptr)721 static int ip4_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
722 {
723 const struct frag_v4_compare_key *key = arg->key;
724 const struct inet_frag_queue *fq = ptr;
725
726 return !!memcmp(&fq->key, key, sizeof(*key));
727 }
728
729 static const struct rhashtable_params ip4_rhash_params = {
730 .head_offset = offsetof(struct inet_frag_queue, node),
731 .key_offset = offsetof(struct inet_frag_queue, key),
732 .key_len = sizeof(struct frag_v4_compare_key),
733 .hashfn = ip4_key_hashfn,
734 .obj_hashfn = ip4_obj_hashfn,
735 .obj_cmpfn = ip4_obj_cmpfn,
736 .automatic_shrinking = true,
737 };
738
ipfrag_init(void)739 void __init ipfrag_init(void)
740 {
741 ip4_frags.constructor = ip4_frag_init;
742 ip4_frags.destructor = ip4_frag_free;
743 ip4_frags.qsize = sizeof(struct ipq);
744 ip4_frags.frag_expire = ip_expire;
745 ip4_frags.frags_cache_name = ip_frag_cache_name;
746 ip4_frags.rhash_params = ip4_rhash_params;
747 if (inet_frags_init(&ip4_frags))
748 panic("IP: failed to allocate ip4_frags cache\n");
749 ip4_frags_ctl_register();
750 register_pernet_subsys(&ip4_frags_ops);
751 }
752
