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 */
58static const char ip_frag_cache_name[] = "ip4-frags";
59
60/* Describe an entry in the "incomplete datagrams" queue. */
61struct 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
71static u8 ip4_frag_ecn(u8 tos)
72{
73 return 1 << (tos & INET_ECN_MASK);
74}
75
76static struct inet_frags ip4_frags;
77
78static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
79 struct sk_buff *prev_tail, struct net_device *dev,
80 int *refs);
81
82
83static void ip4_frag_init(struct inet_frag_queue *q, const void *a)
84{
85 struct ipq *qp = container_of(q, struct ipq, q);
86 const struct frag_v4_compare_key *key = a;
87 struct net *net = q->fqdir->net;
88 struct inet_peer *p = NULL;
89
90 q->key.v4 = *key;
91 qp->ecn = 0;
92 if (q->fqdir->max_dist) {
93 rcu_read_lock();
94 p = inet_getpeer_v4(base: net->ipv4.peers, v4daddr: key->saddr, vif: key->vif);
95 if (p && !refcount_inc_not_zero(r: &p->refcnt))
96 p = NULL;
97 rcu_read_unlock();
98 }
99 qp->peer = p;
100}
101
102static void ip4_frag_free(struct inet_frag_queue *q)
103{
104 struct ipq *qp;
105
106 qp = container_of(q, struct ipq, q);
107 if (qp->peer)
108 inet_putpeer(p: qp->peer);
109}
110
111static bool frag_expire_skip_icmp(u32 user)
112{
113 return user == IP_DEFRAG_AF_PACKET ||
114 ip_defrag_user_in_between(user, lower_bond: IP_DEFRAG_CONNTRACK_IN,
115 upper_bond: __IP_DEFRAG_CONNTRACK_IN_END) ||
116 ip_defrag_user_in_between(user, lower_bond: IP_DEFRAG_CONNTRACK_BRIDGE_IN,
117 upper_bond: __IP_DEFRAG_CONNTRACK_BRIDGE_IN);
118}
119
120/*
121 * Oops, a fragment queue timed out. Kill it and send an ICMP reply.
122 */
123static void ip_expire(struct timer_list *t)
124{
125 enum skb_drop_reason reason = SKB_DROP_REASON_FRAG_REASM_TIMEOUT;
126 struct inet_frag_queue *frag = timer_container_of(frag, t, timer);
127 const struct iphdr *iph;
128 struct sk_buff *head = NULL;
129 struct net *net;
130 struct ipq *qp;
131 int refs = 1;
132
133 qp = container_of(frag, struct ipq, q);
134 net = qp->q.fqdir->net;
135
136 rcu_read_lock();
137
138 /* Paired with WRITE_ONCE() in fqdir_pre_exit(). */
139 if (READ_ONCE(qp->q.fqdir->dead))
140 goto out_rcu_unlock;
141
142 spin_lock(lock: &qp->q.lock);
143
144 if (qp->q.flags & INET_FRAG_COMPLETE)
145 goto out;
146
147 qp->q.flags |= INET_FRAG_DROP;
148 inet_frag_kill(q: &qp->q, refs: &refs);
149 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
150 __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT);
151
152 if (!(qp->q.flags & INET_FRAG_FIRST_IN))
153 goto out;
154
155 /* sk_buff::dev and sk_buff::rbnode are unionized. So we
156 * pull the head out of the tree in order to be able to
157 * deal with head->dev.
158 */
159 head = inet_frag_pull_head(q: &qp->q);
160 if (!head)
161 goto out;
162 head->dev = dev_get_by_index_rcu(net, ifindex: qp->iif);
163 if (!head->dev)
164 goto out;
165
166
167 /* skb has no dst, perform route lookup again */
168 iph = ip_hdr(skb: head);
169 reason = ip_route_input_noref(skb: head, daddr: iph->daddr, saddr: iph->saddr,
170 dscp: ip4h_dscp(ip4h: iph), dev: head->dev);
171 if (reason)
172 goto out;
173
174 /* Only an end host needs to send an ICMP
175 * "Fragment Reassembly Timeout" message, per RFC792.
176 */
177 reason = SKB_DROP_REASON_FRAG_REASM_TIMEOUT;
178 if (frag_expire_skip_icmp(user: qp->q.key.v4.user) &&
179 (skb_rtable(skb: head)->rt_type != RTN_LOCAL))
180 goto out;
181
182 spin_unlock(lock: &qp->q.lock);
183 icmp_send(skb_in: head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, info: 0);
184 goto out_rcu_unlock;
185
186out:
187 spin_unlock(lock: &qp->q.lock);
188out_rcu_unlock:
189 rcu_read_unlock();
190 kfree_skb_reason(skb: head, reason);
191 inet_frag_putn(q: &qp->q, refs);
192}
193
194/* Find the correct entry in the "incomplete datagrams" queue for
195 * this IP datagram, and create new one, if nothing is found.
196 */
197static struct ipq *ip_find(struct net *net, struct iphdr *iph,
198 u32 user, int vif)
199{
200 struct frag_v4_compare_key key = {
201 .saddr = iph->saddr,
202 .daddr = iph->daddr,
203 .user = user,
204 .vif = vif,
205 .id = iph->id,
206 .protocol = iph->protocol,
207 };
208 struct inet_frag_queue *q;
209
210 q = inet_frag_find(fqdir: net->ipv4.fqdir, key: &key);
211 if (!q)
212 return NULL;
213
214 return container_of(q, struct ipq, q);
215}
216
217/* Is the fragment too far ahead to be part of ipq? */
218static int ip_frag_too_far(struct ipq *qp)
219{
220 struct inet_peer *peer = qp->peer;
221 unsigned int max = qp->q.fqdir->max_dist;
222 unsigned int start, end;
223
224 int rc;
225
226 if (!peer || !max)
227 return 0;
228
229 start = qp->rid;
230 end = atomic_inc_return(v: &peer->rid);
231 qp->rid = end;
232
233 rc = qp->q.fragments_tail && (end - start) > max;
234
235 if (rc)
236 __IP_INC_STATS(qp->q.fqdir->net, IPSTATS_MIB_REASMFAILS);
237
238 return rc;
239}
240
241static int ip_frag_reinit(struct ipq *qp)
242{
243 unsigned int sum_truesize = 0;
244
245 if (!mod_timer(timer: &qp->q.timer, expires: jiffies + qp->q.fqdir->timeout)) {
246 refcount_inc(r: &qp->q.refcnt);
247 return -ETIMEDOUT;
248 }
249
250 sum_truesize = inet_frag_rbtree_purge(root: &qp->q.rb_fragments,
251 reason: SKB_DROP_REASON_FRAG_TOO_FAR);
252 sub_frag_mem_limit(fqdir: qp->q.fqdir, val: sum_truesize);
253
254 qp->q.flags = 0;
255 qp->q.len = 0;
256 qp->q.meat = 0;
257 qp->q.rb_fragments = RB_ROOT;
258 qp->q.fragments_tail = NULL;
259 qp->q.last_run_head = NULL;
260 qp->iif = 0;
261 qp->ecn = 0;
262
263 return 0;
264}
265
266/* Add new segment to existing queue. */
267static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb, int *refs)
268{
269 struct net *net = qp->q.fqdir->net;
270 int ihl, end, flags, offset;
271 struct sk_buff *prev_tail;
272 struct net_device *dev;
273 unsigned int fragsize;
274 int err = -ENOENT;
275 SKB_DR(reason);
276 u8 ecn;
277
278 /* If reassembly is already done, @skb must be a duplicate frag. */
279 if (qp->q.flags & INET_FRAG_COMPLETE) {
280 SKB_DR_SET(reason, DUP_FRAG);
281 goto err;
282 }
283
284 if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
285 unlikely(ip_frag_too_far(qp)) &&
286 unlikely(err = ip_frag_reinit(qp))) {
287 inet_frag_kill(q: &qp->q, refs);
288 goto err;
289 }
290
291 ecn = ip4_frag_ecn(tos: ip_hdr(skb)->tos);
292 offset = ntohs(ip_hdr(skb)->frag_off);
293 flags = offset & ~IP_OFFSET;
294 offset &= IP_OFFSET;
295 offset <<= 3; /* offset is in 8-byte chunks */
296 ihl = ip_hdrlen(skb);
297
298 /* Determine the position of this fragment. */
299 end = offset + skb->len - skb_network_offset(skb) - ihl;
300 err = -EINVAL;
301
302 /* Is this the final fragment? */
303 if ((flags & IP_MF) == 0) {
304 /* If we already have some bits beyond end
305 * or have different end, the segment is corrupted.
306 */
307 if (end < qp->q.len ||
308 ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len))
309 goto discard_qp;
310 qp->q.flags |= INET_FRAG_LAST_IN;
311 qp->q.len = end;
312 } else {
313 if (end&7) {
314 end &= ~7;
315 if (skb->ip_summed != CHECKSUM_UNNECESSARY)
316 skb->ip_summed = CHECKSUM_NONE;
317 }
318 if (end > qp->q.len) {
319 /* Some bits beyond end -> corruption. */
320 if (qp->q.flags & INET_FRAG_LAST_IN)
321 goto discard_qp;
322 qp->q.len = end;
323 }
324 }
325 if (end == offset)
326 goto discard_qp;
327
328 err = -ENOMEM;
329 if (!pskb_pull(skb, len: skb_network_offset(skb) + ihl))
330 goto discard_qp;
331
332 err = pskb_trim_rcsum(skb, len: end - offset);
333 if (err)
334 goto discard_qp;
335
336 /* Note : skb->rbnode and skb->dev share the same location. */
337 dev = skb->dev;
338 /* Makes sure compiler wont do silly aliasing games */
339 barrier();
340
341 prev_tail = qp->q.fragments_tail;
342 err = inet_frag_queue_insert(q: &qp->q, skb, offset, end);
343 if (err)
344 goto insert_error;
345
346 if (dev)
347 qp->iif = dev->ifindex;
348
349 qp->q.stamp = skb->tstamp;
350 qp->q.tstamp_type = skb->tstamp_type;
351 qp->q.meat += skb->len;
352 qp->ecn |= ecn;
353 add_frag_mem_limit(fqdir: qp->q.fqdir, val: 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, refs);
372 skb->_skb_refdst = orefdst;
373 if (err)
374 inet_frag_kill(q: &qp->q, refs);
375 return err;
376 }
377
378 skb_dst_drop(skb);
379 skb_orphan(skb);
380 return -EINPROGRESS;
381
382insert_error:
383 if (err == IPFRAG_DUP) {
384 SKB_DR_SET(reason, DUP_FRAG);
385 err = -EINVAL;
386 goto err;
387 }
388 err = -EINVAL;
389 __IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
390discard_qp:
391 inet_frag_kill(q: &qp->q, refs);
392 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
393err:
394 kfree_skb_reason(skb, reason);
395 return err;
396}
397
398static bool ip_frag_coalesce_ok(const struct ipq *qp)
399{
400 return qp->q.key.v4.user == IP_DEFRAG_LOCAL_DELIVER;
401}
402
403/* Build a new IP datagram from all its fragments. */
404static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
405 struct sk_buff *prev_tail, struct net_device *dev,
406 int *refs)
407{
408 struct net *net = qp->q.fqdir->net;
409 struct iphdr *iph;
410 void *reasm_data;
411 int len, err;
412 u8 ecn;
413
414 inet_frag_kill(q: &qp->q, refs);
415
416 ecn = ip_frag_ecn_table[qp->ecn];
417 if (unlikely(ecn == 0xff)) {
418 err = -EINVAL;
419 goto out_fail;
420 }
421
422 /* Make the one we just received the head. */
423 reasm_data = inet_frag_reasm_prepare(q: &qp->q, skb, parent: prev_tail);
424 if (!reasm_data)
425 goto out_nomem;
426
427 len = ip_hdrlen(skb) + qp->q.len;
428 err = -E2BIG;
429 if (len > 65535)
430 goto out_oversize;
431
432 inet_frag_reasm_finish(q: &qp->q, head: skb, reasm_data,
433 try_coalesce: ip_frag_coalesce_ok(qp));
434
435 skb->dev = dev;
436 IPCB(skb)->frag_max_size = max(qp->max_df_size, qp->q.max_size);
437
438 iph = ip_hdr(skb);
439 iph->tot_len = htons(len);
440 iph->tos |= ecn;
441
442 /* When we set IP_DF on a refragmented skb we must also force a
443 * call to ip_fragment to avoid forwarding a DF-skb of size s while
444 * original sender only sent fragments of size f (where f < s).
445 *
446 * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest
447 * frag seen to avoid sending tiny DF-fragments in case skb was built
448 * from one very small df-fragment and one large non-df frag.
449 */
450 if (qp->max_df_size == qp->q.max_size) {
451 IPCB(skb)->flags |= IPSKB_FRAG_PMTU;
452 iph->frag_off = htons(IP_DF);
453 } else {
454 iph->frag_off = 0;
455 }
456
457 ip_send_check(ip: iph);
458
459 __IP_INC_STATS(net, IPSTATS_MIB_REASMOKS);
460 qp->q.rb_fragments = RB_ROOT;
461 qp->q.fragments_tail = NULL;
462 qp->q.last_run_head = NULL;
463 return 0;
464
465out_nomem:
466 net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp);
467 err = -ENOMEM;
468 goto out_fail;
469out_oversize:
470 net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->q.key.v4.saddr);
471out_fail:
472 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
473 return err;
474}
475
476/* Process an incoming IP datagram fragment. */
477int ip_defrag(struct net *net, struct sk_buff *skb, u32 user)
478{
479 struct net_device *dev;
480 struct ipq *qp;
481 int vif;
482
483 __IP_INC_STATS(net, IPSTATS_MIB_REASMREQDS);
484
485 /* Lookup (or create) queue header */
486 rcu_read_lock();
487 dev = skb->dev ? : skb_dst_dev_rcu(skb);
488 vif = l3mdev_master_ifindex_rcu(dev);
489 qp = ip_find(net, iph: ip_hdr(skb), user, vif);
490 if (qp) {
491 int ret, refs = 0;
492
493 spin_lock(lock: &qp->q.lock);
494
495 ret = ip_frag_queue(qp, skb, refs: &refs);
496
497 spin_unlock(lock: &qp->q.lock);
498 rcu_read_unlock();
499 inet_frag_putn(q: &qp->q, refs);
500 return ret;
501 }
502 rcu_read_unlock();
503
504 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
505 kfree_skb(skb);
506 return -ENOMEM;
507}
508EXPORT_SYMBOL(ip_defrag);
509
510struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
511{
512 struct iphdr iph;
513 int netoff;
514 u32 len;
515
516 if (skb->protocol != htons(ETH_P_IP))
517 return skb;
518
519 netoff = skb_network_offset(skb);
520
521 if (skb_copy_bits(skb, offset: netoff, to: &iph, len: sizeof(iph)) < 0)
522 return skb;
523
524 if (iph.ihl < 5 || iph.version != 4)
525 return skb;
526
527 len = ntohs(iph.tot_len);
528 if (skb->len < netoff + len || len < (iph.ihl * 4))
529 return skb;
530
531 if (ip_is_fragment(iph: &iph)) {
532 skb = skb_share_check(skb, GFP_ATOMIC);
533 if (skb) {
534 if (!pskb_may_pull(skb, len: netoff + iph.ihl * 4)) {
535 kfree_skb(skb);
536 return NULL;
537 }
538 if (pskb_trim_rcsum(skb, len: netoff + len)) {
539 kfree_skb(skb);
540 return NULL;
541 }
542 memset(IPCB(skb), c: 0, n: sizeof(struct inet_skb_parm));
543 if (ip_defrag(net, skb, user))
544 return NULL;
545 skb_clear_hash(skb);
546 }
547 }
548 return skb;
549}
550EXPORT_SYMBOL(ip_check_defrag);
551
552#ifdef CONFIG_SYSCTL
553static int dist_min;
554
555static struct ctl_table ip4_frags_ns_ctl_table[] = {
556 {
557 .procname = "ipfrag_high_thresh",
558 .maxlen = sizeof(unsigned long),
559 .mode = 0644,
560 .proc_handler = proc_doulongvec_minmax,
561 },
562 {
563 .procname = "ipfrag_low_thresh",
564 .maxlen = sizeof(unsigned long),
565 .mode = 0644,
566 .proc_handler = proc_doulongvec_minmax,
567 },
568 {
569 .procname = "ipfrag_time",
570 .maxlen = sizeof(int),
571 .mode = 0644,
572 .proc_handler = proc_dointvec_jiffies,
573 },
574 {
575 .procname = "ipfrag_max_dist",
576 .maxlen = sizeof(int),
577 .mode = 0644,
578 .proc_handler = proc_dointvec_minmax,
579 .extra1 = &dist_min,
580 },
581};
582
583/* secret interval has been deprecated */
584static int ip4_frags_secret_interval_unused;
585static struct ctl_table ip4_frags_ctl_table[] = {
586 {
587 .procname = "ipfrag_secret_interval",
588 .data = &ip4_frags_secret_interval_unused,
589 .maxlen = sizeof(int),
590 .mode = 0644,
591 .proc_handler = proc_dointvec_jiffies,
592 },
593};
594
595static int __net_init ip4_frags_ns_ctl_register(struct net *net)
596{
597 struct ctl_table *table;
598 struct ctl_table_header *hdr;
599
600 table = ip4_frags_ns_ctl_table;
601 if (!net_eq(net1: net, net2: &init_net)) {
602 table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL);
603 if (!table)
604 goto err_alloc;
605
606 }
607 table[0].data = &net->ipv4.fqdir->high_thresh;
608 table[0].extra1 = &net->ipv4.fqdir->low_thresh;
609 table[1].data = &net->ipv4.fqdir->low_thresh;
610 table[1].extra2 = &net->ipv4.fqdir->high_thresh;
611 table[2].data = &net->ipv4.fqdir->timeout;
612 table[3].data = &net->ipv4.fqdir->max_dist;
613
614 hdr = register_net_sysctl_sz(net, path: "net/ipv4", table,
615 ARRAY_SIZE(ip4_frags_ns_ctl_table));
616 if (!hdr)
617 goto err_reg;
618
619 net->ipv4.frags_hdr = hdr;
620 return 0;
621
622err_reg:
623 if (!net_eq(net1: net, net2: &init_net))
624 kfree(objp: table);
625err_alloc:
626 return -ENOMEM;
627}
628
629static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net)
630{
631 const struct ctl_table *table;
632
633 table = net->ipv4.frags_hdr->ctl_table_arg;
634 unregister_net_sysctl_table(header: net->ipv4.frags_hdr);
635 kfree(objp: table);
636}
637
638static void __init ip4_frags_ctl_register(void)
639{
640 register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table);
641}
642#else
643static int ip4_frags_ns_ctl_register(struct net *net)
644{
645 return 0;
646}
647
648static void ip4_frags_ns_ctl_unregister(struct net *net)
649{
650}
651
652static void __init ip4_frags_ctl_register(void)
653{
654}
655#endif
656
657static int __net_init ipv4_frags_init_net(struct net *net)
658{
659 int res;
660
661 res = fqdir_init(fqdirp: &net->ipv4.fqdir, f: &ip4_frags, net);
662 if (res < 0)
663 return res;
664 /* Fragment cache limits.
665 *
666 * The fragment memory accounting code, (tries to) account for
667 * the real memory usage, by measuring both the size of frag
668 * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue))
669 * and the SKB's truesize.
670 *
671 * A 64K fragment consumes 129736 bytes (44*2944)+200
672 * (1500 truesize == 2944, sizeof(struct ipq) == 200)
673 *
674 * We will commit 4MB at one time. Should we cross that limit
675 * we will prune down to 3MB, making room for approx 8 big 64K
676 * fragments 8x128k.
677 */
678 net->ipv4.fqdir->high_thresh = 4 * 1024 * 1024;
679 net->ipv4.fqdir->low_thresh = 3 * 1024 * 1024;
680 /*
681 * Important NOTE! Fragment queue must be destroyed before MSL expires.
682 * RFC791 is wrong proposing to prolongate timer each fragment arrival
683 * by TTL.
684 */
685 net->ipv4.fqdir->timeout = IP_FRAG_TIME;
686
687 net->ipv4.fqdir->max_dist = 64;
688
689 res = ip4_frags_ns_ctl_register(net);
690 if (res < 0)
691 fqdir_exit(fqdir: net->ipv4.fqdir);
692 return res;
693}
694
695static void __net_exit ipv4_frags_pre_exit_net(struct net *net)
696{
697 fqdir_pre_exit(fqdir: net->ipv4.fqdir);
698}
699
700static void __net_exit ipv4_frags_exit_net(struct net *net)
701{
702 ip4_frags_ns_ctl_unregister(net);
703 fqdir_exit(fqdir: net->ipv4.fqdir);
704}
705
706static struct pernet_operations ip4_frags_ops = {
707 .init = ipv4_frags_init_net,
708 .pre_exit = ipv4_frags_pre_exit_net,
709 .exit = ipv4_frags_exit_net,
710};
711
712
713static u32 ip4_key_hashfn(const void *data, u32 len, u32 seed)
714{
715 return jhash2(k: data,
716 length: sizeof(struct frag_v4_compare_key) / sizeof(u32), initval: seed);
717}
718
719static u32 ip4_obj_hashfn(const void *data, u32 len, u32 seed)
720{
721 const struct inet_frag_queue *fq = data;
722
723 return jhash2(k: (const u32 *)&fq->key.v4,
724 length: sizeof(struct frag_v4_compare_key) / sizeof(u32), initval: seed);
725}
726
727static int ip4_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
728{
729 const struct frag_v4_compare_key *key = arg->key;
730 const struct inet_frag_queue *fq = ptr;
731
732 return !!memcmp(&fq->key, key, sizeof(*key));
733}
734
735static const struct rhashtable_params ip4_rhash_params = {
736 .head_offset = offsetof(struct inet_frag_queue, node),
737 .key_offset = offsetof(struct inet_frag_queue, key),
738 .key_len = sizeof(struct frag_v4_compare_key),
739 .hashfn = ip4_key_hashfn,
740 .obj_hashfn = ip4_obj_hashfn,
741 .obj_cmpfn = ip4_obj_cmpfn,
742 .automatic_shrinking = true,
743};
744
745void __init ipfrag_init(void)
746{
747 ip4_frags.constructor = ip4_frag_init;
748 ip4_frags.destructor = ip4_frag_free;
749 ip4_frags.qsize = sizeof(struct ipq);
750 ip4_frags.frag_expire = ip_expire;
751 ip4_frags.frags_cache_name = ip_frag_cache_name;
752 ip4_frags.rhash_params = ip4_rhash_params;
753 if (inet_frags_init(&ip4_frags))
754 panic(fmt: "IP: failed to allocate ip4_frags cache\n");
755 ip4_frags_ctl_register();
756 register_pernet_subsys(&ip4_frags_ops);
757}
758