2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * The IP fragmentation functionality.
8 * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG>
9 * Alan Cox <alan@lxorguk.ukuu.org.uk>
12 * Alan Cox : Split from ip.c , see ip_input.c for history.
13 * David S. Miller : Begin massive cleanup...
14 * Andi Kleen : Add sysctls.
15 * xxxx : Overlapfrag bug.
16 * Ultima : ip_expire() kernel panic.
17 * Bill Hawes : Frag accounting and evictor fixes.
18 * John McDonald : 0 length frag bug.
19 * Alexey Kuznetsov: SMP races, threading, cleanup.
20 * Patrick McHardy : LRU queue of frag heads for evictor.
23 #define pr_fmt(fmt) "IPv4: " fmt
25 #include <linux/compiler.h>
26 #include <linux/module.h>
27 #include <linux/types.h>
29 #include <linux/jiffies.h>
30 #include <linux/skbuff.h>
31 #include <linux/list.h>
33 #include <linux/icmp.h>
34 #include <linux/netdevice.h>
35 #include <linux/jhash.h>
36 #include <linux/random.h>
37 #include <linux/slab.h>
38 #include <net/route.h>
43 #include <net/checksum.h>
44 #include <net/inetpeer.h>
45 #include <net/inet_frag.h>
46 #include <linux/tcp.h>
47 #include <linux/udp.h>
48 #include <linux/inet.h>
49 #include <linux/netfilter_ipv4.h>
50 #include <net/inet_ecn.h>
52 /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6
53 * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c
54 * as well. Or notify me, at least. --ANK
57 static int sysctl_ipfrag_max_dist __read_mostly
= 64;
61 struct inet_skb_parm h
;
65 #define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb))
67 /* Describe an entry in the "incomplete datagrams" queue. */
69 struct inet_frag_queue q
;
76 u8 ecn
; /* RFC3168 support */
79 struct inet_peer
*peer
;
82 static inline u8
ip4_frag_ecn(u8 tos
)
84 return 1 << (tos
& INET_ECN_MASK
);
87 static struct inet_frags ip4_frags
;
89 int ip_frag_nqueues(struct net
*net
)
91 return net
->ipv4
.frags
.nqueues
;
94 int ip_frag_mem(struct net
*net
)
96 return sum_frag_mem_limit(&net
->ipv4
.frags
);
99 static int ip_frag_reasm(struct ipq
*qp
, struct sk_buff
*prev
,
100 struct net_device
*dev
);
102 struct ip4_create_arg
{
107 static unsigned int ipqhashfn(__be16 id
, __be32 saddr
, __be32 daddr
, u8 prot
)
109 net_get_random_once(&ip4_frags
.rnd
, sizeof(ip4_frags
.rnd
));
110 return jhash_3words((__force u32
)id
<< 16 | prot
,
111 (__force u32
)saddr
, (__force u32
)daddr
,
115 static unsigned int ip4_hashfn(const struct inet_frag_queue
*q
)
117 const struct ipq
*ipq
;
119 ipq
= container_of(q
, struct ipq
, q
);
120 return ipqhashfn(ipq
->id
, ipq
->saddr
, ipq
->daddr
, ipq
->protocol
);
123 static bool ip4_frag_match(const struct inet_frag_queue
*q
, const void *a
)
125 const struct ipq
*qp
;
126 const struct ip4_create_arg
*arg
= a
;
128 qp
= container_of(q
, struct ipq
, q
);
129 return qp
->id
== arg
->iph
->id
&&
130 qp
->saddr
== arg
->iph
->saddr
&&
131 qp
->daddr
== arg
->iph
->daddr
&&
132 qp
->protocol
== arg
->iph
->protocol
&&
133 qp
->user
== arg
->user
;
136 static void ip4_frag_init(struct inet_frag_queue
*q
, const void *a
)
138 struct ipq
*qp
= container_of(q
, struct ipq
, q
);
139 struct netns_ipv4
*ipv4
= container_of(q
->net
, struct netns_ipv4
,
141 struct net
*net
= container_of(ipv4
, struct net
, ipv4
);
143 const struct ip4_create_arg
*arg
= a
;
145 qp
->protocol
= arg
->iph
->protocol
;
146 qp
->id
= arg
->iph
->id
;
147 qp
->ecn
= ip4_frag_ecn(arg
->iph
->tos
);
148 qp
->saddr
= arg
->iph
->saddr
;
149 qp
->daddr
= arg
->iph
->daddr
;
150 qp
->user
= arg
->user
;
151 qp
->peer
= sysctl_ipfrag_max_dist
?
152 inet_getpeer_v4(net
->ipv4
.peers
, arg
->iph
->saddr
, 1) : NULL
;
155 static __inline__
void ip4_frag_free(struct inet_frag_queue
*q
)
159 qp
= container_of(q
, struct ipq
, q
);
161 inet_putpeer(qp
->peer
);
165 /* Destruction primitives. */
167 static __inline__
void ipq_put(struct ipq
*ipq
)
169 inet_frag_put(&ipq
->q
, &ip4_frags
);
172 /* Kill ipq entry. It is not destroyed immediately,
173 * because caller (and someone more) holds reference count.
175 static void ipq_kill(struct ipq
*ipq
)
177 inet_frag_kill(&ipq
->q
, &ip4_frags
);
181 * Oops, a fragment queue timed out. Kill it and send an ICMP reply.
183 static void ip_expire(unsigned long arg
)
188 qp
= container_of((struct inet_frag_queue
*) arg
, struct ipq
, q
);
189 net
= container_of(qp
->q
.net
, struct net
, ipv4
.frags
);
191 spin_lock(&qp
->q
.lock
);
193 if (qp
->q
.last_in
& INET_FRAG_COMPLETE
)
198 IP_INC_STATS_BH(net
, IPSTATS_MIB_REASMTIMEOUT
);
199 IP_INC_STATS_BH(net
, IPSTATS_MIB_REASMFAILS
);
201 if ((qp
->q
.last_in
& INET_FRAG_FIRST_IN
) && qp
->q
.fragments
!= NULL
) {
202 struct sk_buff
*head
= qp
->q
.fragments
;
203 const struct iphdr
*iph
;
207 head
->dev
= dev_get_by_index_rcu(net
, qp
->iif
);
211 /* skb has no dst, perform route lookup again */
213 err
= ip_route_input_noref(head
, iph
->daddr
, iph
->saddr
,
214 iph
->tos
, head
->dev
);
219 * Only an end host needs to send an ICMP
220 * "Fragment Reassembly Timeout" message, per RFC792.
222 if (qp
->user
== IP_DEFRAG_AF_PACKET
||
223 ((qp
->user
>= IP_DEFRAG_CONNTRACK_IN
) &&
224 (qp
->user
<= __IP_DEFRAG_CONNTRACK_IN_END
) &&
225 (skb_rtable(head
)->rt_type
!= RTN_LOCAL
)))
229 /* Send an ICMP "Fragment Reassembly Timeout" message. */
230 icmp_send(head
, ICMP_TIME_EXCEEDED
, ICMP_EXC_FRAGTIME
, 0);
235 spin_unlock(&qp
->q
.lock
);
239 /* Find the correct entry in the "incomplete datagrams" queue for
240 * this IP datagram, and create new one, if nothing is found.
242 static inline struct ipq
*ip_find(struct net
*net
, struct iphdr
*iph
, u32 user
)
244 struct inet_frag_queue
*q
;
245 struct ip4_create_arg arg
;
251 read_lock(&ip4_frags
.lock
);
252 hash
= ipqhashfn(iph
->id
, iph
->saddr
, iph
->daddr
, iph
->protocol
);
254 q
= inet_frag_find(&net
->ipv4
.frags
, &ip4_frags
, &arg
, hash
);
255 if (IS_ERR_OR_NULL(q
)) {
256 inet_frag_maybe_warn_overflow(q
, pr_fmt());
259 return container_of(q
, struct ipq
, q
);
262 /* Is the fragment too far ahead to be part of ipq? */
263 static inline int ip_frag_too_far(struct ipq
*qp
)
265 struct inet_peer
*peer
= qp
->peer
;
266 unsigned int max
= sysctl_ipfrag_max_dist
;
267 unsigned int start
, end
;
275 end
= atomic_inc_return(&peer
->rid
);
278 rc
= qp
->q
.fragments
&& (end
- start
) > max
;
283 net
= container_of(qp
->q
.net
, struct net
, ipv4
.frags
);
284 IP_INC_STATS_BH(net
, IPSTATS_MIB_REASMFAILS
);
290 static int ip_frag_reinit(struct ipq
*qp
)
293 unsigned int sum_truesize
= 0;
295 if (!mod_timer(&qp
->q
.timer
, jiffies
+ qp
->q
.net
->timeout
)) {
296 atomic_inc(&qp
->q
.refcnt
);
300 fp
= qp
->q
.fragments
;
302 struct sk_buff
*xp
= fp
->next
;
304 sum_truesize
+= fp
->truesize
;
308 sub_frag_mem_limit(&qp
->q
, sum_truesize
);
313 qp
->q
.fragments
= NULL
;
314 qp
->q
.fragments_tail
= NULL
;
321 /* Add new segment to existing queue. */
322 static int ip_frag_queue(struct ipq
*qp
, struct sk_buff
*skb
)
324 struct sk_buff
*prev
, *next
;
325 struct net_device
*dev
;
331 if (qp
->q
.last_in
& INET_FRAG_COMPLETE
)
334 if (!(IPCB(skb
)->flags
& IPSKB_FRAG_COMPLETE
) &&
335 unlikely(ip_frag_too_far(qp
)) &&
336 unlikely(err
= ip_frag_reinit(qp
))) {
341 ecn
= ip4_frag_ecn(ip_hdr(skb
)->tos
);
342 offset
= ntohs(ip_hdr(skb
)->frag_off
);
343 flags
= offset
& ~IP_OFFSET
;
345 offset
<<= 3; /* offset is in 8-byte chunks */
346 ihl
= ip_hdrlen(skb
);
348 /* Determine the position of this fragment. */
349 end
= offset
+ skb
->len
- ihl
;
352 /* Is this the final fragment? */
353 if ((flags
& IP_MF
) == 0) {
354 /* If we already have some bits beyond end
355 * or have different end, the segment is corrupted.
357 if (end
< qp
->q
.len
||
358 ((qp
->q
.last_in
& INET_FRAG_LAST_IN
) && end
!= qp
->q
.len
))
360 qp
->q
.last_in
|= INET_FRAG_LAST_IN
;
365 if (skb
->ip_summed
!= CHECKSUM_UNNECESSARY
)
366 skb
->ip_summed
= CHECKSUM_NONE
;
368 if (end
> qp
->q
.len
) {
369 /* Some bits beyond end -> corruption. */
370 if (qp
->q
.last_in
& INET_FRAG_LAST_IN
)
379 if (pskb_pull(skb
, ihl
) == NULL
)
382 err
= pskb_trim_rcsum(skb
, end
- offset
);
386 /* Find out which fragments are in front and at the back of us
387 * in the chain of fragments so far. We must know where to put
388 * this fragment, right?
390 prev
= qp
->q
.fragments_tail
;
391 if (!prev
|| FRAG_CB(prev
)->offset
< offset
) {
396 for (next
= qp
->q
.fragments
; next
!= NULL
; next
= next
->next
) {
397 if (FRAG_CB(next
)->offset
>= offset
)
403 /* We found where to put this one. Check for overlap with
404 * preceding fragment, and, if needed, align things so that
405 * any overlaps are eliminated.
408 int i
= (FRAG_CB(prev
)->offset
+ prev
->len
) - offset
;
416 if (!pskb_pull(skb
, i
))
418 if (skb
->ip_summed
!= CHECKSUM_UNNECESSARY
)
419 skb
->ip_summed
= CHECKSUM_NONE
;
425 while (next
&& FRAG_CB(next
)->offset
< end
) {
426 int i
= end
- FRAG_CB(next
)->offset
; /* overlap is 'i' bytes */
429 /* Eat head of the next overlapped fragment
430 * and leave the loop. The next ones cannot overlap.
432 if (!pskb_pull(next
, i
))
434 FRAG_CB(next
)->offset
+= i
;
436 if (next
->ip_summed
!= CHECKSUM_UNNECESSARY
)
437 next
->ip_summed
= CHECKSUM_NONE
;
440 struct sk_buff
*free_it
= next
;
442 /* Old fragment is completely overridden with
450 qp
->q
.fragments
= next
;
452 qp
->q
.meat
-= free_it
->len
;
453 sub_frag_mem_limit(&qp
->q
, free_it
->truesize
);
458 FRAG_CB(skb
)->offset
= offset
;
460 /* Insert this fragment in the chain of fragments. */
463 qp
->q
.fragments_tail
= skb
;
467 qp
->q
.fragments
= skb
;
471 qp
->iif
= dev
->ifindex
;
474 qp
->q
.stamp
= skb
->tstamp
;
475 qp
->q
.meat
+= skb
->len
;
477 add_frag_mem_limit(&qp
->q
, skb
->truesize
);
479 qp
->q
.last_in
|= INET_FRAG_FIRST_IN
;
481 if (ip_hdr(skb
)->frag_off
& htons(IP_DF
) &&
482 skb
->len
+ ihl
> qp
->q
.max_size
)
483 qp
->q
.max_size
= skb
->len
+ ihl
;
485 if (qp
->q
.last_in
== (INET_FRAG_FIRST_IN
| INET_FRAG_LAST_IN
) &&
486 qp
->q
.meat
== qp
->q
.len
) {
487 unsigned long orefdst
= skb
->_skb_refdst
;
489 skb
->_skb_refdst
= 0UL;
490 err
= ip_frag_reasm(qp
, prev
, dev
);
491 skb
->_skb_refdst
= orefdst
;
496 inet_frag_lru_move(&qp
->q
);
505 /* Build a new IP datagram from all its fragments. */
507 static int ip_frag_reasm(struct ipq
*qp
, struct sk_buff
*prev
,
508 struct net_device
*dev
)
510 struct net
*net
= container_of(qp
->q
.net
, struct net
, ipv4
.frags
);
512 struct sk_buff
*fp
, *head
= qp
->q
.fragments
;
521 ecn
= ip_frag_ecn_table
[qp
->ecn
];
522 if (unlikely(ecn
== 0xff)) {
526 /* Make the one we just received the head. */
529 fp
= skb_clone(head
, GFP_ATOMIC
);
533 fp
->next
= head
->next
;
535 qp
->q
.fragments_tail
= fp
;
538 skb_morph(head
, qp
->q
.fragments
);
539 head
->next
= qp
->q
.fragments
->next
;
541 consume_skb(qp
->q
.fragments
);
542 qp
->q
.fragments
= head
;
545 WARN_ON(head
== NULL
);
546 WARN_ON(FRAG_CB(head
)->offset
!= 0);
548 /* Allocate a new buffer for the datagram. */
549 ihlen
= ip_hdrlen(head
);
550 len
= ihlen
+ qp
->q
.len
;
556 /* Head of list must not be cloned. */
557 if (skb_unclone(head
, GFP_ATOMIC
))
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 if (skb_has_frag_list(head
)) {
564 struct sk_buff
*clone
;
567 if ((clone
= alloc_skb(0, GFP_ATOMIC
)) == NULL
)
569 clone
->next
= head
->next
;
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
->len
= clone
->data_len
= head
->data_len
- plen
;
576 head
->data_len
-= clone
->len
;
577 head
->len
-= clone
->len
;
579 clone
->ip_summed
= head
->ip_summed
;
580 add_frag_mem_limit(&qp
->q
, clone
->truesize
);
583 skb_push(head
, head
->data
- skb_network_header(head
));
585 sum_truesize
= head
->truesize
;
586 for (fp
= head
->next
; fp
;) {
589 struct sk_buff
*next
= fp
->next
;
591 sum_truesize
+= fp
->truesize
;
592 if (head
->ip_summed
!= fp
->ip_summed
)
593 head
->ip_summed
= CHECKSUM_NONE
;
594 else if (head
->ip_summed
== CHECKSUM_COMPLETE
)
595 head
->csum
= csum_add(head
->csum
, fp
->csum
);
597 if (skb_try_coalesce(head
, fp
, &headstolen
, &delta
)) {
598 kfree_skb_partial(fp
, headstolen
);
600 if (!skb_shinfo(head
)->frag_list
)
601 skb_shinfo(head
)->frag_list
= fp
;
602 head
->data_len
+= fp
->len
;
603 head
->len
+= fp
->len
;
604 head
->truesize
+= fp
->truesize
;
608 sub_frag_mem_limit(&qp
->q
, sum_truesize
);
612 head
->tstamp
= qp
->q
.stamp
;
613 IPCB(head
)->frag_max_size
= qp
->q
.max_size
;
616 /* max_size != 0 implies at least one fragment had IP_DF set */
617 iph
->frag_off
= qp
->q
.max_size
? htons(IP_DF
) : 0;
618 iph
->tot_len
= htons(len
);
620 IP_INC_STATS_BH(net
, IPSTATS_MIB_REASMOKS
);
621 qp
->q
.fragments
= NULL
;
622 qp
->q
.fragments_tail
= NULL
;
626 LIMIT_NETDEBUG(KERN_ERR
pr_fmt("queue_glue: no memory for gluing queue %p\n"),
631 net_info_ratelimited("Oversized IP packet from %pI4\n", &qp
->saddr
);
633 IP_INC_STATS_BH(net
, IPSTATS_MIB_REASMFAILS
);
637 /* Process an incoming IP datagram fragment. */
638 int ip_defrag(struct sk_buff
*skb
, u32 user
)
643 net
= skb
->dev
? dev_net(skb
->dev
) : dev_net(skb_dst(skb
)->dev
);
644 IP_INC_STATS_BH(net
, IPSTATS_MIB_REASMREQDS
);
646 /* Lookup (or create) queue header */
647 if ((qp
= ip_find(net
, ip_hdr(skb
), user
)) != NULL
) {
650 spin_lock(&qp
->q
.lock
);
652 ret
= ip_frag_queue(qp
, skb
);
654 spin_unlock(&qp
->q
.lock
);
659 IP_INC_STATS_BH(net
, IPSTATS_MIB_REASMFAILS
);
663 EXPORT_SYMBOL(ip_defrag
);
665 struct sk_buff
*ip_check_defrag(struct sk_buff
*skb
, u32 user
)
670 if (skb
->protocol
!= htons(ETH_P_IP
))
673 if (!skb_copy_bits(skb
, 0, &iph
, sizeof(iph
)))
676 if (iph
.ihl
< 5 || iph
.version
!= 4)
679 len
= ntohs(iph
.tot_len
);
680 if (skb
->len
< len
|| len
< (iph
.ihl
* 4))
683 if (ip_is_fragment(&iph
)) {
684 skb
= skb_share_check(skb
, GFP_ATOMIC
);
686 if (!pskb_may_pull(skb
, iph
.ihl
*4))
688 if (pskb_trim_rcsum(skb
, len
))
690 memset(IPCB(skb
), 0, sizeof(struct inet_skb_parm
));
691 if (ip_defrag(skb
, user
))
698 EXPORT_SYMBOL(ip_check_defrag
);
703 static struct ctl_table ip4_frags_ns_ctl_table
[] = {
705 .procname
= "ipfrag_high_thresh",
706 .data
= &init_net
.ipv4
.frags
.high_thresh
,
707 .maxlen
= sizeof(int),
709 .proc_handler
= proc_dointvec
712 .procname
= "ipfrag_low_thresh",
713 .data
= &init_net
.ipv4
.frags
.low_thresh
,
714 .maxlen
= sizeof(int),
716 .proc_handler
= proc_dointvec
719 .procname
= "ipfrag_time",
720 .data
= &init_net
.ipv4
.frags
.timeout
,
721 .maxlen
= sizeof(int),
723 .proc_handler
= proc_dointvec_jiffies
,
728 static struct ctl_table ip4_frags_ctl_table
[] = {
730 .procname
= "ipfrag_secret_interval",
731 .data
= &ip4_frags
.secret_interval
,
732 .maxlen
= sizeof(int),
734 .proc_handler
= proc_dointvec_jiffies
,
737 .procname
= "ipfrag_max_dist",
738 .data
= &sysctl_ipfrag_max_dist
,
739 .maxlen
= sizeof(int),
741 .proc_handler
= proc_dointvec_minmax
,
747 static int __net_init
ip4_frags_ns_ctl_register(struct net
*net
)
749 struct ctl_table
*table
;
750 struct ctl_table_header
*hdr
;
752 table
= ip4_frags_ns_ctl_table
;
753 if (!net_eq(net
, &init_net
)) {
754 table
= kmemdup(table
, sizeof(ip4_frags_ns_ctl_table
), GFP_KERNEL
);
758 table
[0].data
= &net
->ipv4
.frags
.high_thresh
;
759 table
[1].data
= &net
->ipv4
.frags
.low_thresh
;
760 table
[2].data
= &net
->ipv4
.frags
.timeout
;
762 /* Don't export sysctls to unprivileged users */
763 if (net
->user_ns
!= &init_user_ns
)
764 table
[0].procname
= NULL
;
767 hdr
= register_net_sysctl(net
, "net/ipv4", table
);
771 net
->ipv4
.frags_hdr
= hdr
;
775 if (!net_eq(net
, &init_net
))
781 static void __net_exit
ip4_frags_ns_ctl_unregister(struct net
*net
)
783 struct ctl_table
*table
;
785 table
= net
->ipv4
.frags_hdr
->ctl_table_arg
;
786 unregister_net_sysctl_table(net
->ipv4
.frags_hdr
);
790 static void ip4_frags_ctl_register(void)
792 register_net_sysctl(&init_net
, "net/ipv4", ip4_frags_ctl_table
);
795 static inline int ip4_frags_ns_ctl_register(struct net
*net
)
800 static inline void ip4_frags_ns_ctl_unregister(struct net
*net
)
804 static inline void ip4_frags_ctl_register(void)
809 static int __net_init
ipv4_frags_init_net(struct net
*net
)
811 /* Fragment cache limits.
813 * The fragment memory accounting code, (tries to) account for
814 * the real memory usage, by measuring both the size of frag
815 * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue))
816 * and the SKB's truesize.
818 * A 64K fragment consumes 129736 bytes (44*2944)+200
819 * (1500 truesize == 2944, sizeof(struct ipq) == 200)
821 * We will commit 4MB at one time. Should we cross that limit
822 * we will prune down to 3MB, making room for approx 8 big 64K
825 net
->ipv4
.frags
.high_thresh
= 4 * 1024 * 1024;
826 net
->ipv4
.frags
.low_thresh
= 3 * 1024 * 1024;
828 * Important NOTE! Fragment queue must be destroyed before MSL expires.
829 * RFC791 is wrong proposing to prolongate timer each fragment arrival
832 net
->ipv4
.frags
.timeout
= IP_FRAG_TIME
;
834 inet_frags_init_net(&net
->ipv4
.frags
);
836 return ip4_frags_ns_ctl_register(net
);
839 static void __net_exit
ipv4_frags_exit_net(struct net
*net
)
841 ip4_frags_ns_ctl_unregister(net
);
842 inet_frags_exit_net(&net
->ipv4
.frags
, &ip4_frags
);
845 static struct pernet_operations ip4_frags_ops
= {
846 .init
= ipv4_frags_init_net
,
847 .exit
= ipv4_frags_exit_net
,
850 void __init
ipfrag_init(void)
852 ip4_frags_ctl_register();
853 register_pernet_subsys(&ip4_frags_ops
);
854 ip4_frags
.hashfn
= ip4_hashfn
;
855 ip4_frags
.constructor
= ip4_frag_init
;
856 ip4_frags
.destructor
= ip4_frag_free
;
857 ip4_frags
.skb_free
= NULL
;
858 ip4_frags
.qsize
= sizeof(struct ipq
);
859 ip4_frags
.match
= ip4_frag_match
;
860 ip4_frags
.frag_expire
= ip_expire
;
861 ip4_frags
.secret_interval
= 10 * 60 * HZ
;
862 inet_frags_init(&ip4_frags
);