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/*
* IPv6 fragment reassembly
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* 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.
*/
#define pr_fmt(fmt) "IPv6: " fmt
#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 <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/export.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>
#include <net/inet_frag.h>
#include <net/inet_ecn.h>
static const char ip6_frag_cache_name[] = "ip6-frags";
struct ip6frag_skb_cb {
struct inet6_skb_parm h;
int offset;
};
#define FRAG6_CB(skb) ((struct ip6frag_skb_cb *)((skb)->cb))
static u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
{
return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
}
static struct inet_frags ip6_frags;
static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
struct net_device *dev);
/*
* 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 inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
const struct in6_addr *daddr)
{
net_get_random_once(&ip6_frags.rnd, sizeof(ip6_frags.rnd));
return jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
(__force u32)id, ip6_frags.rnd);
}
static unsigned int ip6_hashfn(const struct inet_frag_queue *q)
{
const struct frag_queue *fq;
fq = container_of(q, struct frag_queue, q);
return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr);
}
bool ip6_frag_match(const struct inet_frag_queue *q, const void *a)
{
const struct frag_queue *fq;
const struct ip6_create_arg *arg = a;
fq = container_of(q, struct frag_queue, q);
return fq->id == arg->id &&
fq->user == arg->user &&
ipv6_addr_equal(&fq->saddr, arg->src) &&
ipv6_addr_equal(&fq->daddr, arg->dst);
}
EXPORT_SYMBOL(ip6_frag_match);
void ip6_frag_init(struct inet_frag_queue *q, const void *a)
{
struct frag_queue *fq = container_of(q, struct frag_queue, q);
const struct ip6_create_arg *arg = a;
fq->id = arg->id;
fq->user = arg->user;
fq->saddr = *arg->src;
fq->daddr = *arg->dst;
fq->ecn = arg->ecn;
}
EXPORT_SYMBOL(ip6_frag_init);
void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq,
struct inet_frags *frags)
{
struct net_device *dev = NULL;
spin_lock(&fq->q.lock);
if (fq->q.flags & INET_FRAG_COMPLETE)
goto out;
inet_frag_kill(&fq->q, frags);
rcu_read_lock();
dev = dev_get_by_index_rcu(net, fq->iif);
if (!dev)
goto out_rcu_unlock;
IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
if (fq->q.flags & INET_FRAG_EVICTED)
goto out_rcu_unlock;
IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
/* Don't send error if the first segment did not arrive. */
if (!(fq->q.flags & INET_FRAG_FIRST_IN) || !fq->q.fragments)
goto out_rcu_unlock;
/* But use as source device on which LAST ARRIVED
* segment was received. And do not use fq->dev
* pointer directly, device might already disappeared.
*/
fq->q.fragments->dev = dev;
icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
out_rcu_unlock:
rcu_read_unlock();
out:
spin_unlock(&fq->q.lock);
inet_frag_put(&fq->q, frags);
}
EXPORT_SYMBOL(ip6_expire_frag_queue);
static void ip6_frag_expire(unsigned long data)
{
struct frag_queue *fq;
struct net *net;
fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
net = container_of(fq->q.net, struct net, ipv6.frags);
ip6_expire_frag_queue(net, fq, &ip6_frags);
}
static struct frag_queue *
fq_find(struct net *net, __be32 id, const struct in6_addr *src,
const struct in6_addr *dst, u8 ecn)
{
struct inet_frag_queue *q;
struct ip6_create_arg arg;
unsigned int hash;
arg.id = id;
arg.user = IP6_DEFRAG_LOCAL_DELIVER;
arg.src = src;
arg.dst = dst;
arg.ecn = ecn;
hash = inet6_hash_frag(id, src, dst);
q = inet_frag_find(&net->ipv6.frags, &ip6_frags,
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