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 /* Paired with WRITE_ONCE() in fqdir_pre_exit(). */
148 if (READ_ONCE(qp->q.fqdir->dead))
149 goto out_rcu_unlock;
150
151 spin_lock(&qp->q.lock);
152
153 if (qp->q.flags & INET_FRAG_COMPLETE)
154 goto out;
155
156 ipq_kill(qp);
157 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
158 __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT);
159
160 if (!(qp->q.flags & INET_FRAG_FIRST_IN))
161 goto out;
162
163 /* sk_buff::dev and sk_buff::rbnode are unionized. So we
164 * pull the head out of the tree in order to be able to
165 * deal with head->dev.
166 */
167 head = inet_frag_pull_head(&qp->q);
168 if (!head)
169 goto out;
170 head->dev = dev_get_by_index_rcu(net, qp->iif);
171 if (!head->dev)
172 goto out;
173
174
175 /* skb has no dst, perform route lookup again */
176 iph = ip_hdr(head);
177 err = ip_route_input_noref(head, iph->daddr, iph->saddr,
178 iph->tos, head->dev);
179 if (err)
180 goto out;
181
182 /* Only an end host needs to send an ICMP
183 * "Fragment Reassembly Timeout" message, per RFC792.
184 */
185 if (frag_expire_skip_icmp(qp->q.key.v4.user) &&
186 (skb_rtable(head)->rt_type != RTN_LOCAL))
187 goto out;
188
189 spin_unlock(&qp->q.lock);
190 icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
191 goto out_rcu_unlock;
192
193 out:
194 spin_unlock(&qp->q.lock);
195 out_rcu_unlock:
196 rcu_read_unlock();
197 kfree_skb(head);
198 ipq_put(qp);
199 }
200
201 /* Find the correct entry in the "incomplete datagrams" queue for
202 * this IP datagram, and create new one, if nothing is found.
203 */
ip_find(struct net * net,struct iphdr * iph,u32 user,int vif)204 static struct ipq *ip_find(struct net *net, struct iphdr *iph,
205 u32 user, int vif)
206 {
207 struct frag_v4_compare_key key = {
208 .saddr = iph->saddr,
209 .daddr = iph->daddr,
210 .user = user,
211 .vif = vif,
212 .id = iph->id,
213 .protocol = iph->protocol,
214 };
215 struct inet_frag_queue *q;
216
217 q = inet_frag_find(net->ipv4.fqdir, &key);
218 if (!q)
219 return NULL;
220
221 return container_of(q, struct ipq, q);
222 }
223
224 /* Is the fragment too far ahead to be part of ipq? */
ip_frag_too_far(struct ipq * qp)225 static int ip_frag_too_far(struct ipq *qp)
226 {
227 struct inet_peer *peer = qp->peer;
228 unsigned int max = qp->q.fqdir->max_dist;
229 unsigned int start, end;
230
231 int rc;
232
233 if (!peer || !max)
234 return 0;
235
236 start = qp->rid;
237 end = atomic_inc_return(&peer->rid);
238 qp->rid = end;
239
240 rc = qp->q.fragments_tail && (end - start) > max;
241
242 if (rc)
243 __IP_INC_STATS(qp->q.fqdir->net, IPSTATS_MIB_REASMFAILS);
244
245 return rc;
246 }
247
ip_frag_reinit(struct ipq * qp)248 static int ip_frag_reinit(struct ipq *qp)
249 {
250 unsigned int sum_truesize = 0;
251
252 if (!mod_timer(&qp->q.timer, jiffies + qp->q.fqdir->timeout)) {
253 refcount_inc(&qp->q.refcnt);
254 return -ETIMEDOUT;
255 }
256
257 sum_truesize = inet_frag_rbtree_purge(&qp->q.rb_fragments);
258 sub_frag_mem_limit(qp->q.fqdir, sum_truesize);
259
260 qp->q.flags = 0;
261 qp->q.len = 0;
262 qp->q.meat = 0;
263 qp->q.rb_fragments = RB_ROOT;
264 qp->q.fragments_tail = NULL;
265 qp->q.last_run_head = NULL;
266 qp->iif = 0;
267 qp->ecn = 0;
268
269 return 0;
270 }
271
272 /* Add new segment to existing queue. */
ip_frag_queue(struct ipq * qp,struct sk_buff * skb)273 static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
274 {
275 struct net *net = qp->q.fqdir->net;
276 int ihl, end, flags, offset;
277 struct sk_buff *prev_tail;
278 struct net_device *dev;
279 unsigned int fragsize;
280 int err = -ENOENT;
281 u8 ecn;
282
283 if (qp->q.flags & INET_FRAG_COMPLETE)
284 goto err;
285
286 if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
287 unlikely(ip_frag_too_far(qp)) &&
288 unlikely(err = ip_frag_reinit(qp))) {
289 ipq_kill(qp);
290 goto err;
291 }
292
293 ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
294 offset = ntohs(ip_hdr(skb)->frag_off);
295 flags = offset & ~IP_OFFSET;
296 offset &= IP_OFFSET;
297 offset <<= 3; /* offset is in 8-byte chunks */
298 ihl = ip_hdrlen(skb);
299
300 /* Determine the position of this fragment. */
301 end = offset + skb->len - skb_network_offset(skb) - ihl;
302 err = -EINVAL;
303
304 /* Is this the final fragment? */
305 if ((flags & IP_MF) == 0) {
306 /* If we already have some bits beyond end
307 * or have different end, the segment is corrupted.
308 */
309 if (end < qp->q.len ||
310 ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len))
311 goto discard_qp;
312 qp->q.flags |= INET_FRAG_LAST_IN;
313 qp->q.len = end;
314 } else {
315 if (end&7) {
316 end &= ~7;
317 if (skb->ip_summed != CHECKSUM_UNNECESSARY)
318 skb->ip_summed = CHECKSUM_NONE;
319 }
320 if (end > qp->q.len) {
321 /* Some bits beyond end -> corruption. */
322 if (qp->q.flags & INET_FRAG_LAST_IN)
323 goto discard_qp;
324 qp->q.len = end;
325 }
326 }
327 if (end == offset)
328 goto discard_qp;
329
330 err = -ENOMEM;
331 if (!pskb_pull(skb, skb_network_offset(skb) + ihl))
332 goto discard_qp;
333
334 err = pskb_trim_rcsum(skb, end - offset);
335 if (err)
336 goto discard_qp;
337
338 /* Note : skb->rbnode and skb->dev share the same location. */
339 dev = skb->dev;
340 /* Makes sure compiler wont do silly aliasing games */
341 barrier();
342
343 prev_tail = qp->q.fragments_tail;
344 err = inet_frag_queue_insert(&qp->q, skb, offset, end);
345 if (err)
346 goto insert_error;
347
348 if (dev)
349 qp->iif = dev->ifindex;
350
351 qp->q.stamp = skb->tstamp;
352 qp->q.meat += skb->len;
353 qp->ecn |= ecn;
354 add_frag_mem_limit(qp->q.fqdir, skb->truesize);
355 if (offset == 0)
356 qp->q.flags |= INET_FRAG_FIRST_IN;
357
358 fragsize = skb->len + ihl;
359
360 if (fragsize > qp->q.max_size)
361 qp->q.max_size = fragsize;
362
363 if (ip_hdr(skb)->frag_off & htons(IP_DF) &&
364 fragsize > qp->max_df_size)
365 qp->max_df_size = fragsize;
366
367 if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
368 qp->q.meat == qp->q.len) {
369 unsigned long orefdst = skb->_skb_refdst;
370
371 skb->_skb_refdst = 0UL;
372 err = ip_frag_reasm(qp, skb, prev_tail, dev);
373 skb->_skb_refdst = orefdst;
374 if (err)
375 inet_frag_kill(&qp->q);
376 return err;
377 }
378
379 skb_dst_drop(skb);
380 return -EINPROGRESS;
381
382 insert_error:
383 if (err == IPFRAG_DUP) {
384 kfree_skb(skb);
385 return -EINVAL;
386 }
387 err = -EINVAL;
388 __IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
389 discard_qp:
390 inet_frag_kill(&qp->q);
391 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
392 err:
393 kfree_skb(skb);
394 return err;
395 }
396
ip_frag_coalesce_ok(const struct ipq * qp)397 static bool ip_frag_coalesce_ok(const struct ipq *qp)
398 {
399 return qp->q.key.v4.user == IP_DEFRAG_LOCAL_DELIVER;
400 }
401
402 /* 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)403 static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
404 struct sk_buff *prev_tail, struct net_device *dev)
405 {
406 struct net *net = qp->q.fqdir->net;
407 struct iphdr *iph;
408 void *reasm_data;
409 int len, err;
410 u8 ecn;
411
412 ipq_kill(qp);
413
414 ecn = ip_frag_ecn_table[qp->ecn];
415 if (unlikely(ecn == 0xff)) {
416 err = -EINVAL;
417 goto out_fail;
418 }
419
420 /* Make the one we just received the head. */
421 reasm_data = inet_frag_reasm_prepare(&qp->q, skb, prev_tail);
422 if (!reasm_data)
423 goto out_nomem;
424
425 len = ip_hdrlen(skb) + qp->q.len;
426 err = -E2BIG;
427 if (len > 65535)
428 goto out_oversize;
429
430 inet_frag_reasm_finish(&qp->q, skb, reasm_data,
431 ip_frag_coalesce_ok(qp));
432
433 skb->dev = dev;
434 IPCB(skb)->frag_max_size = max(qp->max_df_size, qp->q.max_size);
435
436 iph = ip_hdr(skb);
437 iph->tot_len = htons(len);
438 iph->tos |= ecn;
439
440 /* When we set IP_DF on a refragmented skb we must also force a
441 * call to ip_fragment to avoid forwarding a DF-skb of size s while
442 * original sender only sent fragments of size f (where f < s).
443 *
444 * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest
445 * frag seen to avoid sending tiny DF-fragments in case skb was built
446 * from one very small df-fragment and one large non-df frag.
447 */
448 if (qp->max_df_size == qp->q.max_size) {
449 IPCB(skb)->flags |= IPSKB_FRAG_PMTU;
450 iph->frag_off = htons(IP_DF);
451 } else {
452 iph->frag_off = 0;
453 }
454
455 ip_send_check(iph);
456
457 __IP_INC_STATS(net, IPSTATS_MIB_REASMOKS);
458 qp->q.rb_fragments = RB_ROOT;
459 qp->q.fragments_tail = NULL;
460 qp->q.last_run_head = NULL;
461 return 0;
462
463 out_nomem:
464 net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp);
465 err = -ENOMEM;
466 goto out_fail;
467 out_oversize:
468 net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->q.key.v4.saddr);
469 out_fail:
470 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
471 return err;
472 }
473
474 /* Process an incoming IP datagram fragment. */
ip_defrag(struct net * net,struct sk_buff * skb,u32 user)475 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user)
476 {
477 struct net_device *dev = skb->dev ? : skb_dst(skb)->dev;
478 int vif = l3mdev_master_ifindex_rcu(dev);
479 struct ipq *qp;
480
481 __IP_INC_STATS(net, IPSTATS_MIB_REASMREQDS);
482 skb_orphan(skb);
483
484 /* Lookup (or create) queue header */
485 qp = ip_find(net, ip_hdr(skb), user, vif);
486 if (qp) {
487 int ret;
488
489 spin_lock(&qp->q.lock);
490
491 ret = ip_frag_queue(qp, skb);
492
493 spin_unlock(&qp->q.lock);
494 ipq_put(qp);
495 return ret;
496 }
497
498 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
499 kfree_skb(skb);
500 return -ENOMEM;
501 }
502 EXPORT_SYMBOL(ip_defrag);
503
ip_check_defrag(struct net * net,struct sk_buff * skb,u32 user)504 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
505 {
506 struct iphdr iph;
507 int netoff;
508 u32 len;
509
510 if (skb->protocol != htons(ETH_P_IP))
511 return skb;
512
513 netoff = skb_network_offset(skb);
514
515 if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0)
516 return skb;
517
518 if (iph.ihl < 5 || iph.version != 4)
519 return skb;
520
521 len = ntohs(iph.tot_len);
522 if (skb->len < netoff + len || len < (iph.ihl * 4))
523 return skb;
524
525 if (ip_is_fragment(&iph)) {
526 skb = skb_share_check(skb, GFP_ATOMIC);
527 if (skb) {
528 if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) {
529 kfree_skb(skb);
530 return NULL;
531 }
532 if (pskb_trim_rcsum(skb, netoff + len)) {
533 kfree_skb(skb);
534 return NULL;
535 }
536 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
537 if (ip_defrag(net, skb, user))
538 return NULL;
539 skb_clear_hash(skb);
540 }
541 }
542 return skb;
543 }
544 EXPORT_SYMBOL(ip_check_defrag);
545
546 #ifdef CONFIG_SYSCTL
547 static int dist_min;
548
549 static struct ctl_table ip4_frags_ns_ctl_table[] = {
550 {
551 .procname = "ipfrag_high_thresh",
552 .maxlen = sizeof(unsigned long),
553 .mode = 0644,
554 .proc_handler = proc_doulongvec_minmax,
555 },
556 {
557 .procname = "ipfrag_low_thresh",
558 .maxlen = sizeof(unsigned long),
559 .mode = 0644,
560 .proc_handler = proc_doulongvec_minmax,
561 },
562 {
563 .procname = "ipfrag_time",
564 .maxlen = sizeof(int),
565 .mode = 0644,
566 .proc_handler = proc_dointvec_jiffies,
567 },
568 {
569 .procname = "ipfrag_max_dist",
570 .maxlen = sizeof(int),
571 .mode = 0644,
572 .proc_handler = proc_dointvec_minmax,
573 .extra1 = &dist_min,
574 },
575 { }
576 };
577
578 /* secret interval has been deprecated */
579 static int ip4_frags_secret_interval_unused;
580 static struct ctl_table ip4_frags_ctl_table[] = {
581 {
582 .procname = "ipfrag_secret_interval",
583 .data = &ip4_frags_secret_interval_unused,
584 .maxlen = sizeof(int),
585 .mode = 0644,
586 .proc_handler = proc_dointvec_jiffies,
587 },
588 { }
589 };
590
ip4_frags_ns_ctl_register(struct net * net)591 static int __net_init ip4_frags_ns_ctl_register(struct net *net)
592 {
593 struct ctl_table *table;
594 struct ctl_table_header *hdr;
595
596 table = ip4_frags_ns_ctl_table;
597 if (!net_eq(net, &init_net)) {
598 table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL);
599 if (!table)
600 goto err_alloc;
601
602 }
603 table[0].data = &net->ipv4.fqdir->high_thresh;
604 table[0].extra1 = &net->ipv4.fqdir->low_thresh;
605 table[1].data = &net->ipv4.fqdir->low_thresh;
606 table[1].extra2 = &net->ipv4.fqdir->high_thresh;
607 table[2].data = &net->ipv4.fqdir->timeout;
608 table[3].data = &net->ipv4.fqdir->max_dist;
609
610 hdr = register_net_sysctl(net, "net/ipv4", table);
611 if (!hdr)
612 goto err_reg;
613
614 net->ipv4.frags_hdr = hdr;
615 return 0;
616
617 err_reg:
618 if (!net_eq(net, &init_net))
619 kfree(table);
620 err_alloc:
621 return -ENOMEM;
622 }
623
ip4_frags_ns_ctl_unregister(struct net * net)624 static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net)
625 {
626 struct ctl_table *table;
627
628 table = net->ipv4.frags_hdr->ctl_table_arg;
629 unregister_net_sysctl_table(net->ipv4.frags_hdr);
630 kfree(table);
631 }
632
ip4_frags_ctl_register(void)633 static void __init ip4_frags_ctl_register(void)
634 {
635 register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table);
636 }
637 #else
ip4_frags_ns_ctl_register(struct net * net)638 static int ip4_frags_ns_ctl_register(struct net *net)
639 {
640 return 0;
641 }
642
ip4_frags_ns_ctl_unregister(struct net * net)643 static void ip4_frags_ns_ctl_unregister(struct net *net)
644 {
645 }
646
ip4_frags_ctl_register(void)647 static void __init ip4_frags_ctl_register(void)
648 {
649 }
650 #endif
651
ipv4_frags_init_net(struct net * net)652 static int __net_init ipv4_frags_init_net(struct net *net)
653 {
654 int res;
655
656 res = fqdir_init(&net->ipv4.fqdir, &ip4_frags, net);
657 if (res < 0)
658 return res;
659 /* Fragment cache limits.
660 *
661 * The fragment memory accounting code, (tries to) account for
662 * the real memory usage, by measuring both the size of frag
663 * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue))
664 * and the SKB's truesize.
665 *
666 * A 64K fragment consumes 129736 bytes (44*2944)+200
667 * (1500 truesize == 2944, sizeof(struct ipq) == 200)
668 *
669 * We will commit 4MB at one time. Should we cross that limit
670 * we will prune down to 3MB, making room for approx 8 big 64K
671 * fragments 8x128k.
672 */
673 net->ipv4.fqdir->high_thresh = 4 * 1024 * 1024;
674 net->ipv4.fqdir->low_thresh = 3 * 1024 * 1024;
675 /*
676 * Important NOTE! Fragment queue must be destroyed before MSL expires.
677 * RFC791 is wrong proposing to prolongate timer each fragment arrival
678 * by TTL.
679 */
680 net->ipv4.fqdir->timeout = IP_FRAG_TIME;
681
682 net->ipv4.fqdir->max_dist = 64;
683
684 res = ip4_frags_ns_ctl_register(net);
685 if (res < 0)
686 fqdir_exit(net->ipv4.fqdir);
687 return res;
688 }
689
ipv4_frags_pre_exit_net(struct net * net)690 static void __net_exit ipv4_frags_pre_exit_net(struct net *net)
691 {
692 fqdir_pre_exit(net->ipv4.fqdir);
693 }
694
ipv4_frags_exit_net(struct net * net)695 static void __net_exit ipv4_frags_exit_net(struct net *net)
696 {
697 ip4_frags_ns_ctl_unregister(net);
698 fqdir_exit(net->ipv4.fqdir);
699 }
700
701 static struct pernet_operations ip4_frags_ops = {
702 .init = ipv4_frags_init_net,
703 .pre_exit = ipv4_frags_pre_exit_net,
704 .exit = ipv4_frags_exit_net,
705 };
706
707
ip4_key_hashfn(const void * data,u32 len,u32 seed)708 static u32 ip4_key_hashfn(const void *data, u32 len, u32 seed)
709 {
710 return jhash2(data,
711 sizeof(struct frag_v4_compare_key) / sizeof(u32), seed);
712 }
713
ip4_obj_hashfn(const void * data,u32 len,u32 seed)714 static u32 ip4_obj_hashfn(const void *data, u32 len, u32 seed)
715 {
716 const struct inet_frag_queue *fq = data;
717
718 return jhash2((const u32 *)&fq->key.v4,
719 sizeof(struct frag_v4_compare_key) / sizeof(u32), seed);
720 }
721
ip4_obj_cmpfn(struct rhashtable_compare_arg * arg,const void * ptr)722 static int ip4_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
723 {
724 const struct frag_v4_compare_key *key = arg->key;
725 const struct inet_frag_queue *fq = ptr;
726
727 return !!memcmp(&fq->key, key, sizeof(*key));
728 }
729
730 static const struct rhashtable_params ip4_rhash_params = {
731 .head_offset = offsetof(struct inet_frag_queue, node),
732 .key_offset = offsetof(struct inet_frag_queue, key),
733 .key_len = sizeof(struct frag_v4_compare_key),
734 .hashfn = ip4_key_hashfn,
735 .obj_hashfn = ip4_obj_hashfn,
736 .obj_cmpfn = ip4_obj_cmpfn,
737 .automatic_shrinking = true,
738 };
739
ipfrag_init(void)740 void __init ipfrag_init(void)
741 {
742 ip4_frags.constructor = ip4_frag_init;
743 ip4_frags.destructor = ip4_frag_free;
744 ip4_frags.qsize = sizeof(struct ipq);
745 ip4_frags.frag_expire = ip_expire;
746 ip4_frags.frags_cache_name = ip_frag_cache_name;
747 ip4_frags.rhash_params = ip4_rhash_params;
748 if (inet_frags_init(&ip4_frags))
749 panic("IP: failed to allocate ip4_frags cache\n");
750 ip4_frags_ctl_register();
751 register_pernet_subsys(&ip4_frags_ops);
752 }
753