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/*
* IPv6 fragment reassembly
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* $Id: reassembly.c,v 1.26 2001/03/07 22:00:57 davem Exp $
*
* Based on: net/ipv4/ip_fragment.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
/*
* Fixes:
* Andi Kleen Make it work with multiple hosts.
* More RFC compliance.
*
* Horst von Brand Add missing #include <linux/string.h>
* Alexey Kuznetsov SMP races, threading, cleanup.
* Patrick McHardy LRU queue of frag heads for evictor.
* Mitsuru KANDA @USAGI Register inet6_protocol{}.
* David Stevens and
* YOSHIFUJI,H. @USAGI Always remove fragment header to
* calculate ICV correctly.
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/jiffies.h>
#include <linux/net.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <net/sock.h>
#include <net/snmp.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/rawv6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
int sysctl_ip6frag_high_thresh __read_mostly = 256*1024;
int sysctl_ip6frag_low_thresh __read_mostly = 192*1024;
int sysctl_ip6frag_time __read_mostly = IPV6_FRAG_TIMEOUT;
struct ip6frag_skb_cb
{
struct inet6_skb_parm h;
int offset;
};
#define FRAG6_CB(skb) ((struct ip6frag_skb_cb*)((skb)->cb))
/*
* Equivalent of ipv4 struct ipq
*/
struct frag_queue
{
struct hlist_node list;
struct list_head lru_list; /* lru list member */
__be32 id; /* fragment id */
struct in6_addr saddr;
struct in6_addr daddr;
spinlock_t lock;
atomic_t refcnt;
struct timer_list timer; /* expire timer */
struct sk_buff *fragments;
int len;
int meat;
int iif;
ktime_t stamp;
unsigned int csum;
__u8 last_in; /* has first/last segment arrived? */
#define COMPLETE 4
#define FIRST_IN 2
#define LAST_IN 1
__u16 nhoffset;
};
/* Hash table. */
#define IP6Q_HASHSZ 64
static struct hlist_head ip6_frag_hash[IP6Q_HASHSZ];
static DEFINE_RWLOCK(ip6_frag_lock);
static u32 ip6_frag_hash_rnd;
static LIST_HEAD(ip6_frag_lru_list);
int ip6_frag_nqueues = 0;
static __inline__ void __fq_unlink(struct frag_queue *fq)
{
hlist_del(&fq->list);
list_del(&fq->lru_list);
ip6_frag_nqueues--;
}
static __inline__ void fq_unlink(struct frag_queue *fq)
{
write_lock(&ip6_frag_lock);
__fq_unlink(fq);
write_unlock(&ip6_frag_lock);
}
/*
* callers should be careful not to use the hash value outside the ipfrag_lock
* as doing so could race with ipfrag_hash_rnd being recalculated.
*/
static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr,
struct in6_addr *daddr)
{
u32 a, b, c;
a = (__force u32)saddr->s6_addr32[0];
b = (__force u32)saddr->s6_addr32[1];
c = (__force u32)saddr->s6_addr32[2];
a += JHASH_GOLDEN_RATIO;
b += JHASH_GOLDEN_RATIO;
c += ip6_frag_hash_rnd;
__jhash_mix(a, b, c);
a += (__force u32)saddr->s6_addr32[3];
b += (__force u32)daddr->s6_addr32[0];
c += (__force u32)daddr->s6_addr32[1];
__jhash_mix(a, b, c);
a += (__force u32)daddr->s6_addr32[2];
b += (__force u32)daddr->s6_addr32[3];
c += (__force u32)id;
__jhash_mix(a, b, c);
return c & (IP6Q_HASHSZ - 1);
}
static struct timer_list ip6_frag_secret_timer;
int sysctl_ip6frag_secret_interval __read_mostly = 10 * 60 * HZ;
static void ip6_frag_secret_rebuild(unsigned long dummy)
{
unsigned long now = jiffies;
int i;
write_lock(&ip6_frag_lock);
get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32));
for (i = 0; i < IP6Q_HASHSZ; i++) {
struct frag_queue *q;
struct hlist_node *p, *n;
hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], list) {
unsigned int hval = ip6qhashfn(q->id,
&q->saddr,
&q->daddr);
if (hval != i) {
hlist_del(&q->list);
/* Relink to new hash chain. */
hlist_add_head(&q->list,
&ip6_frag_hash[hval]);
}
}
}
write_unlock(&ip6_frag_lock);
mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval);
}
atomic_t ip6_frag_mem = ATOMIC_INIT(0);
/* Memory Tracking Functions. */
static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
{
if (work)
*work -= skb->truesize;
atomic_sub(skb->truesize, &ip6_frag_mem);
kfree_skb(skb);
}
static inline void frag_free_queue(struct frag_queue *fq, int *work)
{
if (work)
*work -= sizeof(struct frag_queue);
atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem);
kfree(fq);
}
static inline struct frag_queue *frag_alloc_queue(void)
{
struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC);
if(!fq)
return NULL;
atomic_add(sizeof(struct frag_queue), &ip6_frag_mem);
return fq;
}
/* Destruction primitives. */
/* Complete destruction of fq. */
static void ip6_frag_destroy(struct frag_queue *fq, int *work)
{
struct sk_buff *fp;
<
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