2005-04-16 22:20:36 +00:00
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* The IP fragmentation functionality.
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2007-02-09 14:24:47 +00:00
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*
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2005-04-16 22:20:36 +00:00
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* Version: $Id: ip_fragment.c,v 1.59 2002/01/12 07:54:56 davem Exp $
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*
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* Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG>
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* Alan Cox <Alan.Cox@linux.org>
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*
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* Fixes:
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* Alan Cox : Split from ip.c , see ip_input.c for history.
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* David S. Miller : Begin massive cleanup...
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* Andi Kleen : Add sysctls.
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* xxxx : Overlapfrag bug.
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* Ultima : ip_expire() kernel panic.
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* Bill Hawes : Frag accounting and evictor fixes.
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* John McDonald : 0 length frag bug.
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* Alexey Kuznetsov: SMP races, threading, cleanup.
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* Patrick McHardy : LRU queue of frag heads for evictor.
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*/
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2005-12-14 07:14:27 +00:00
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#include <linux/compiler.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/jiffies.h>
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#include <linux/skbuff.h>
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#include <linux/list.h>
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#include <linux/ip.h>
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#include <linux/icmp.h>
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#include <linux/netdevice.h>
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#include <linux/jhash.h>
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#include <linux/random.h>
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#include <net/sock.h>
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#include <net/ip.h>
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#include <net/icmp.h>
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#include <net/checksum.h>
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2005-12-14 07:14:27 +00:00
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#include <net/inetpeer.h>
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2007-10-15 09:24:19 +00:00
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#include <net/inet_frag.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <linux/inet.h>
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#include <linux/netfilter_ipv4.h>
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/* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6
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* code now. If you change something here, _PLEASE_ update ipv6/reassembly.c
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* as well. Or notify me, at least. --ANK
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*/
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2006-09-22 21:15:41 +00:00
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int sysctl_ipfrag_max_dist __read_mostly = 64;
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2005-12-14 07:14:27 +00:00
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2005-04-16 22:20:36 +00:00
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struct ipfrag_skb_cb
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{
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struct inet_skb_parm h;
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int offset;
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};
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#define FRAG_CB(skb) ((struct ipfrag_skb_cb*)((skb)->cb))
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/* Describe an entry in the "incomplete datagrams" queue. */
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struct ipq {
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2007-10-15 09:24:19 +00:00
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struct inet_frag_queue q;
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2005-04-16 22:20:36 +00:00
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u32 user;
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2006-09-27 05:19:02 +00:00
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__be32 saddr;
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__be32 daddr;
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__be16 id;
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2005-04-16 22:20:36 +00:00
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u8 protocol;
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2005-12-14 07:14:27 +00:00
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int iif;
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unsigned int rid;
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struct inet_peer *peer;
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2005-04-16 22:20:36 +00:00
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};
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2007-10-15 09:33:45 +00:00
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struct inet_frags_ctl ip4_frags_ctl __read_mostly = {
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/*
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* Fragment cache limits. We will commit 256K at one time. Should we
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* cross that limit we will prune down to 192K. This should cope with
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* even the most extreme cases without allowing an attacker to
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* measurably harm machine performance.
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*/
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.high_thresh = 256 * 1024,
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.low_thresh = 192 * 1024,
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/*
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* Important NOTE! Fragment queue must be destroyed before MSL expires.
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* RFC791 is wrong proposing to prolongate timer each fragment arrival
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* by TTL.
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*/
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.timeout = IP_FRAG_TIME,
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.secret_interval = 10 * 60 * HZ,
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};
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2007-10-15 09:31:52 +00:00
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static struct inet_frags ip4_frags;
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2005-04-16 22:20:36 +00:00
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2007-10-15 09:31:52 +00:00
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int ip_frag_nqueues(void)
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{
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return ip4_frags.nqueues;
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}
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2005-04-16 22:20:36 +00:00
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2007-10-15 09:31:52 +00:00
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int ip_frag_mem(void)
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{
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return atomic_read(&ip4_frags.mem);
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}
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2005-04-16 22:20:36 +00:00
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2007-10-14 07:38:15 +00:00
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static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
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struct net_device *dev);
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2006-09-27 05:19:02 +00:00
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static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot)
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2005-04-16 22:20:36 +00:00
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{
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2006-09-27 05:19:02 +00:00
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return jhash_3words((__force u32)id << 16 | prot,
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(__force u32)saddr, (__force u32)daddr,
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2007-10-15 09:31:52 +00:00
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ip4_frags.rnd) & (INETFRAGS_HASHSZ - 1);
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2005-04-16 22:20:36 +00:00
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}
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2007-10-15 09:38:08 +00:00
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static unsigned int ip4_hashfn(struct inet_frag_queue *q)
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2005-04-16 22:20:36 +00:00
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{
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2007-10-15 09:38:08 +00:00
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struct ipq *ipq;
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2005-04-16 22:20:36 +00:00
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2007-10-15 09:38:08 +00:00
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ipq = container_of(q, struct ipq, q);
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return ipqhashfn(ipq->id, ipq->saddr, ipq->daddr, ipq->protocol);
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2005-04-16 22:20:36 +00:00
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}
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/* Memory Tracking Functions. */
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static __inline__ void frag_kfree_skb(struct sk_buff *skb, int *work)
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{
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if (work)
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*work -= skb->truesize;
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2007-10-15 09:31:52 +00:00
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atomic_sub(skb->truesize, &ip4_frags.mem);
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2005-04-16 22:20:36 +00:00
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kfree_skb(skb);
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}
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2007-10-15 09:39:14 +00:00
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static __inline__ void ip4_frag_free(struct inet_frag_queue *q)
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2005-04-16 22:20:36 +00:00
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{
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2007-10-15 09:39:14 +00:00
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struct ipq *qp;
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qp = container_of(q, struct ipq, q);
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if (qp->peer)
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inet_putpeer(qp->peer);
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2005-04-16 22:20:36 +00:00
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kfree(qp);
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}
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static __inline__ struct ipq *frag_alloc_queue(void)
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{
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struct ipq *qp = kmalloc(sizeof(struct ipq), GFP_ATOMIC);
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2007-03-09 04:44:43 +00:00
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if (!qp)
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2005-04-16 22:20:36 +00:00
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return NULL;
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2007-10-15 09:31:52 +00:00
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atomic_add(sizeof(struct ipq), &ip4_frags.mem);
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2005-04-16 22:20:36 +00:00
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return qp;
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}
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/* Destruction primitives. */
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2007-10-15 09:41:09 +00:00
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static __inline__ void ipq_put(struct ipq *ipq)
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2005-04-16 22:20:36 +00:00
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{
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2007-10-15 09:41:56 +00:00
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inet_frag_put(&ipq->q, &ip4_frags);
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2005-04-16 22:20:36 +00:00
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}
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/* Kill ipq entry. It is not destroyed immediately,
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* because caller (and someone more) holds reference count.
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*/
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static void ipq_kill(struct ipq *ipq)
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{
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2007-10-15 09:37:18 +00:00
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inet_frag_kill(&ipq->q, &ip4_frags);
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2005-04-16 22:20:36 +00:00
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}
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2007-02-09 14:24:47 +00:00
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/* Memory limiting on fragments. Evictor trashes the oldest
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2005-04-16 22:20:36 +00:00
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* fragment queue until we are back under the threshold.
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*/
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static void ip_evictor(void)
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{
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2007-10-15 09:40:06 +00:00
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int evicted;
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evicted = inet_frag_evictor(&ip4_frags);
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if (evicted)
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IP_ADD_STATS_BH(IPSTATS_MIB_REASMFAILS, evicted);
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2005-04-16 22:20:36 +00:00
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}
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/*
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* Oops, a fragment queue timed out. Kill it and send an ICMP reply.
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*/
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static void ip_expire(unsigned long arg)
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{
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struct ipq *qp = (struct ipq *) arg;
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2007-10-15 09:24:19 +00:00
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spin_lock(&qp->q.lock);
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2005-04-16 22:20:36 +00:00
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2007-10-15 09:24:19 +00:00
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if (qp->q.last_in & COMPLETE)
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2005-04-16 22:20:36 +00:00
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goto out;
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ipq_kill(qp);
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IP_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT);
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IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
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2007-10-15 09:24:19 +00:00
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if ((qp->q.last_in&FIRST_IN) && qp->q.fragments != NULL) {
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struct sk_buff *head = qp->q.fragments;
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2005-04-16 22:20:36 +00:00
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/* Send an ICMP "Fragment Reassembly Timeout" message. */
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2007-09-17 18:56:21 +00:00
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if ((head->dev = dev_get_by_index(&init_net, qp->iif)) != NULL) {
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2005-04-16 22:20:36 +00:00
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icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
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dev_put(head->dev);
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}
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}
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out:
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2007-10-15 09:24:19 +00:00
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spin_unlock(&qp->q.lock);
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2007-10-15 09:41:09 +00:00
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ipq_put(qp);
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2005-04-16 22:20:36 +00:00
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}
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/* Creation primitives. */
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2006-04-10 05:43:55 +00:00
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static struct ipq *ip_frag_intern(struct ipq *qp_in)
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2005-04-16 22:20:36 +00:00
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{
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struct ipq *qp;
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2005-11-16 20:55:37 +00:00
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#ifdef CONFIG_SMP
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struct hlist_node *n;
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#endif
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2006-04-10 05:43:55 +00:00
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unsigned int hash;
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2007-10-15 09:31:52 +00:00
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write_lock(&ip4_frags.lock);
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2006-04-10 05:43:55 +00:00
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hash = ipqhashfn(qp_in->id, qp_in->saddr, qp_in->daddr,
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qp_in->protocol);
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2005-04-16 22:20:36 +00:00
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#ifdef CONFIG_SMP
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/* With SMP race we have to recheck hash table, because
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* such entry could be created on other cpu, while we
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* promoted read lock to write lock.
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*/
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2007-10-15 09:31:52 +00:00
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hlist_for_each_entry(qp, n, &ip4_frags.hash[hash], q.list) {
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2007-03-09 04:44:43 +00:00
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if (qp->id == qp_in->id &&
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qp->saddr == qp_in->saddr &&
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qp->daddr == qp_in->daddr &&
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qp->protocol == qp_in->protocol &&
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qp->user == qp_in->user) {
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2007-10-15 09:24:19 +00:00
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atomic_inc(&qp->q.refcnt);
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2007-10-15 09:31:52 +00:00
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write_unlock(&ip4_frags.lock);
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2007-10-15 09:24:19 +00:00
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qp_in->q.last_in |= COMPLETE;
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2007-10-15 09:41:09 +00:00
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ipq_put(qp_in);
|
2005-04-16 22:20:36 +00:00
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return qp;
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}
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}
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#endif
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qp = qp_in;
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|
2007-10-15 09:33:45 +00:00
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if (!mod_timer(&qp->q.timer, jiffies + ip4_frags_ctl.timeout))
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2007-10-15 09:24:19 +00:00
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atomic_inc(&qp->q.refcnt);
|
2005-04-16 22:20:36 +00:00
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2007-10-15 09:24:19 +00:00
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atomic_inc(&qp->q.refcnt);
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2007-10-15 09:31:52 +00:00
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hlist_add_head(&qp->q.list, &ip4_frags.hash[hash]);
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2007-10-15 09:24:19 +00:00
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INIT_LIST_HEAD(&qp->q.lru_list);
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2007-10-15 09:31:52 +00:00
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list_add_tail(&qp->q.lru_list, &ip4_frags.lru_list);
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ip4_frags.nqueues++;
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write_unlock(&ip4_frags.lock);
|
2005-04-16 22:20:36 +00:00
|
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|
return qp;
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}
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/* Add an entry to the 'ipq' queue for a newly received IP datagram. */
|
2006-04-10 05:43:55 +00:00
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static struct ipq *ip_frag_create(struct iphdr *iph, u32 user)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
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struct ipq *qp;
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if ((qp = frag_alloc_queue()) == NULL)
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|
goto out_nomem;
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qp->protocol = iph->protocol;
|
2007-10-15 09:24:19 +00:00
|
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|
qp->q.last_in = 0;
|
2005-04-16 22:20:36 +00:00
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|
qp->id = iph->id;
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qp->saddr = iph->saddr;
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qp->daddr = iph->daddr;
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qp->user = user;
|
2007-10-15 09:24:19 +00:00
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qp->q.len = 0;
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qp->q.meat = 0;
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|
qp->q.fragments = NULL;
|
2005-04-16 22:20:36 +00:00
|
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|
qp->iif = 0;
|
2005-12-14 07:14:27 +00:00
|
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|
qp->peer = sysctl_ipfrag_max_dist ? inet_getpeer(iph->saddr, 1) : NULL;
|
2005-04-16 22:20:36 +00:00
|
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|
/* Initialize a timer for this entry. */
|
2007-10-15 09:24:19 +00:00
|
|
|
init_timer(&qp->q.timer);
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|
|
qp->q.timer.data = (unsigned long) qp; /* pointer to queue */
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|
|
qp->q.timer.function = ip_expire; /* expire function */
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|
|
spin_lock_init(&qp->q.lock);
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|
|
|
atomic_set(&qp->q.refcnt, 1);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2006-04-10 05:43:55 +00:00
|
|
|
return ip_frag_intern(qp);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
out_nomem:
|
2005-08-10 03:50:53 +00:00
|
|
|
LIMIT_NETDEBUG(KERN_ERR "ip_frag_create: no memory left !\n");
|
2005-04-16 22:20:36 +00:00
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
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|
|
/* Find the correct entry in the "incomplete datagrams" queue for
|
|
|
|
* this IP datagram, and create new one, if nothing is found.
|
|
|
|
*/
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|
|
|
static inline struct ipq *ip_find(struct iphdr *iph, u32 user)
|
|
|
|
{
|
2006-01-06 21:24:29 +00:00
|
|
|
__be16 id = iph->id;
|
2006-09-27 05:19:02 +00:00
|
|
|
__be32 saddr = iph->saddr;
|
|
|
|
__be32 daddr = iph->daddr;
|
2005-04-16 22:20:36 +00:00
|
|
|
__u8 protocol = iph->protocol;
|
2006-04-10 05:43:55 +00:00
|
|
|
unsigned int hash;
|
2005-04-16 22:20:36 +00:00
|
|
|
struct ipq *qp;
|
2005-11-16 20:55:37 +00:00
|
|
|
struct hlist_node *n;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-15 09:31:52 +00:00
|
|
|
read_lock(&ip4_frags.lock);
|
2006-04-10 05:43:55 +00:00
|
|
|
hash = ipqhashfn(id, saddr, daddr, protocol);
|
2007-10-15 09:31:52 +00:00
|
|
|
hlist_for_each_entry(qp, n, &ip4_frags.hash[hash], q.list) {
|
2007-03-09 04:44:43 +00:00
|
|
|
if (qp->id == id &&
|
|
|
|
qp->saddr == saddr &&
|
|
|
|
qp->daddr == daddr &&
|
|
|
|
qp->protocol == protocol &&
|
|
|
|
qp->user == user) {
|
2007-10-15 09:24:19 +00:00
|
|
|
atomic_inc(&qp->q.refcnt);
|
2007-10-15 09:31:52 +00:00
|
|
|
read_unlock(&ip4_frags.lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
return qp;
|
|
|
|
}
|
|
|
|
}
|
2007-10-15 09:31:52 +00:00
|
|
|
read_unlock(&ip4_frags.lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2006-04-10 05:43:55 +00:00
|
|
|
return ip_frag_create(iph, user);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2005-12-14 07:14:27 +00:00
|
|
|
/* Is the fragment too far ahead to be part of ipq? */
|
|
|
|
static inline int ip_frag_too_far(struct ipq *qp)
|
|
|
|
{
|
|
|
|
struct inet_peer *peer = qp->peer;
|
|
|
|
unsigned int max = sysctl_ipfrag_max_dist;
|
|
|
|
unsigned int start, end;
|
|
|
|
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
if (!peer || !max)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
start = qp->rid;
|
|
|
|
end = atomic_inc_return(&peer->rid);
|
|
|
|
qp->rid = end;
|
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
rc = qp->q.fragments && (end - start) > max;
|
2005-12-14 07:14:27 +00:00
|
|
|
|
|
|
|
if (rc) {
|
|
|
|
IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
|
|
|
|
}
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int ip_frag_reinit(struct ipq *qp)
|
|
|
|
{
|
|
|
|
struct sk_buff *fp;
|
|
|
|
|
2007-10-15 09:33:45 +00:00
|
|
|
if (!mod_timer(&qp->q.timer, jiffies + ip4_frags_ctl.timeout)) {
|
2007-10-15 09:24:19 +00:00
|
|
|
atomic_inc(&qp->q.refcnt);
|
2005-12-14 07:14:27 +00:00
|
|
|
return -ETIMEDOUT;
|
|
|
|
}
|
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
fp = qp->q.fragments;
|
2005-12-14 07:14:27 +00:00
|
|
|
do {
|
|
|
|
struct sk_buff *xp = fp->next;
|
|
|
|
frag_kfree_skb(fp, NULL);
|
|
|
|
fp = xp;
|
|
|
|
} while (fp);
|
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.last_in = 0;
|
|
|
|
qp->q.len = 0;
|
|
|
|
qp->q.meat = 0;
|
|
|
|
qp->q.fragments = NULL;
|
2005-12-14 07:14:27 +00:00
|
|
|
qp->iif = 0;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Add new segment to existing queue. */
|
2007-10-14 07:38:15 +00:00
|
|
|
static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct sk_buff *prev, *next;
|
2007-10-14 07:38:15 +00:00
|
|
|
struct net_device *dev;
|
2005-04-16 22:20:36 +00:00
|
|
|
int flags, offset;
|
|
|
|
int ihl, end;
|
2007-10-14 07:38:15 +00:00
|
|
|
int err = -ENOENT;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
if (qp->q.last_in & COMPLETE)
|
2005-04-16 22:20:36 +00:00
|
|
|
goto err;
|
|
|
|
|
2005-12-14 07:14:27 +00:00
|
|
|
if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
|
2007-10-14 07:38:15 +00:00
|
|
|
unlikely(ip_frag_too_far(qp)) &&
|
|
|
|
unlikely(err = ip_frag_reinit(qp))) {
|
2005-12-14 07:14:27 +00:00
|
|
|
ipq_kill(qp);
|
|
|
|
goto err;
|
|
|
|
}
|
|
|
|
|
2007-04-21 05:47:35 +00:00
|
|
|
offset = ntohs(ip_hdr(skb)->frag_off);
|
2005-04-16 22:20:36 +00:00
|
|
|
flags = offset & ~IP_OFFSET;
|
|
|
|
offset &= IP_OFFSET;
|
|
|
|
offset <<= 3; /* offset is in 8-byte chunks */
|
2007-03-12 23:09:15 +00:00
|
|
|
ihl = ip_hdrlen(skb);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* Determine the position of this fragment. */
|
2007-02-09 14:24:47 +00:00
|
|
|
end = offset + skb->len - ihl;
|
2007-10-14 07:38:15 +00:00
|
|
|
err = -EINVAL;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* Is this the final fragment? */
|
|
|
|
if ((flags & IP_MF) == 0) {
|
|
|
|
/* If we already have some bits beyond end
|
|
|
|
* or have different end, the segment is corrrupted.
|
|
|
|
*/
|
2007-10-15 09:24:19 +00:00
|
|
|
if (end < qp->q.len ||
|
|
|
|
((qp->q.last_in & LAST_IN) && end != qp->q.len))
|
2005-04-16 22:20:36 +00:00
|
|
|
goto err;
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.last_in |= LAST_IN;
|
|
|
|
qp->q.len = end;
|
2005-04-16 22:20:36 +00:00
|
|
|
} else {
|
|
|
|
if (end&7) {
|
|
|
|
end &= ~7;
|
|
|
|
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
|
|
|
|
skb->ip_summed = CHECKSUM_NONE;
|
|
|
|
}
|
2007-10-15 09:24:19 +00:00
|
|
|
if (end > qp->q.len) {
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Some bits beyond end -> corruption. */
|
2007-10-15 09:24:19 +00:00
|
|
|
if (qp->q.last_in & LAST_IN)
|
2005-04-16 22:20:36 +00:00
|
|
|
goto err;
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.len = end;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
if (end == offset)
|
|
|
|
goto err;
|
|
|
|
|
2007-10-14 07:38:15 +00:00
|
|
|
err = -ENOMEM;
|
2005-04-16 22:20:36 +00:00
|
|
|
if (pskb_pull(skb, ihl) == NULL)
|
|
|
|
goto err;
|
2007-10-14 07:38:15 +00:00
|
|
|
|
|
|
|
err = pskb_trim_rcsum(skb, end - offset);
|
|
|
|
if (err)
|
2005-04-16 22:20:36 +00:00
|
|
|
goto err;
|
|
|
|
|
|
|
|
/* Find out which fragments are in front and at the back of us
|
|
|
|
* in the chain of fragments so far. We must know where to put
|
|
|
|
* this fragment, right?
|
|
|
|
*/
|
|
|
|
prev = NULL;
|
2007-10-15 09:24:19 +00:00
|
|
|
for (next = qp->q.fragments; next != NULL; next = next->next) {
|
2005-04-16 22:20:36 +00:00
|
|
|
if (FRAG_CB(next)->offset >= offset)
|
|
|
|
break; /* bingo! */
|
|
|
|
prev = next;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* We found where to put this one. Check for overlap with
|
|
|
|
* preceding fragment, and, if needed, align things so that
|
|
|
|
* any overlaps are eliminated.
|
|
|
|
*/
|
|
|
|
if (prev) {
|
|
|
|
int i = (FRAG_CB(prev)->offset + prev->len) - offset;
|
|
|
|
|
|
|
|
if (i > 0) {
|
|
|
|
offset += i;
|
2007-10-14 07:38:15 +00:00
|
|
|
err = -EINVAL;
|
2005-04-16 22:20:36 +00:00
|
|
|
if (end <= offset)
|
|
|
|
goto err;
|
2007-10-14 07:38:15 +00:00
|
|
|
err = -ENOMEM;
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!pskb_pull(skb, i))
|
|
|
|
goto err;
|
|
|
|
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
|
|
|
|
skb->ip_summed = CHECKSUM_NONE;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2007-10-14 07:38:15 +00:00
|
|
|
err = -ENOMEM;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
while (next && FRAG_CB(next)->offset < end) {
|
|
|
|
int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */
|
|
|
|
|
|
|
|
if (i < next->len) {
|
|
|
|
/* Eat head of the next overlapped fragment
|
|
|
|
* and leave the loop. The next ones cannot overlap.
|
|
|
|
*/
|
|
|
|
if (!pskb_pull(next, i))
|
|
|
|
goto err;
|
|
|
|
FRAG_CB(next)->offset += i;
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.meat -= i;
|
2005-04-16 22:20:36 +00:00
|
|
|
if (next->ip_summed != CHECKSUM_UNNECESSARY)
|
|
|
|
next->ip_summed = CHECKSUM_NONE;
|
|
|
|
break;
|
|
|
|
} else {
|
|
|
|
struct sk_buff *free_it = next;
|
|
|
|
|
2006-12-12 18:48:59 +00:00
|
|
|
/* Old fragment is completely overridden with
|
2005-04-16 22:20:36 +00:00
|
|
|
* new one drop it.
|
|
|
|
*/
|
|
|
|
next = next->next;
|
|
|
|
|
|
|
|
if (prev)
|
|
|
|
prev->next = next;
|
|
|
|
else
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.fragments = next;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.meat -= free_it->len;
|
2005-04-16 22:20:36 +00:00
|
|
|
frag_kfree_skb(free_it, NULL);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
FRAG_CB(skb)->offset = offset;
|
|
|
|
|
|
|
|
/* Insert this fragment in the chain of fragments. */
|
|
|
|
skb->next = next;
|
|
|
|
if (prev)
|
|
|
|
prev->next = skb;
|
|
|
|
else
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.fragments = skb;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-14 07:38:15 +00:00
|
|
|
dev = skb->dev;
|
|
|
|
if (dev) {
|
|
|
|
qp->iif = dev->ifindex;
|
|
|
|
skb->dev = NULL;
|
|
|
|
}
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.stamp = skb->tstamp;
|
|
|
|
qp->q.meat += skb->len;
|
2007-10-15 09:31:52 +00:00
|
|
|
atomic_add(skb->truesize, &ip4_frags.mem);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (offset == 0)
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.last_in |= FIRST_IN;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
if (qp->q.last_in == (FIRST_IN | LAST_IN) && qp->q.meat == qp->q.len)
|
2007-10-14 07:38:15 +00:00
|
|
|
return ip_frag_reasm(qp, prev, dev);
|
|
|
|
|
2007-10-15 09:31:52 +00:00
|
|
|
write_lock(&ip4_frags.lock);
|
|
|
|
list_move_tail(&qp->q.lru_list, &ip4_frags.lru_list);
|
|
|
|
write_unlock(&ip4_frags.lock);
|
2007-10-14 07:38:15 +00:00
|
|
|
return -EINPROGRESS;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
err:
|
|
|
|
kfree_skb(skb);
|
2007-10-14 07:38:15 +00:00
|
|
|
return err;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/* Build a new IP datagram from all its fragments. */
|
|
|
|
|
2007-10-14 07:38:15 +00:00
|
|
|
static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
|
|
|
|
struct net_device *dev)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct iphdr *iph;
|
2007-10-15 09:24:19 +00:00
|
|
|
struct sk_buff *fp, *head = qp->q.fragments;
|
2005-04-16 22:20:36 +00:00
|
|
|
int len;
|
|
|
|
int ihlen;
|
2007-10-14 07:38:15 +00:00
|
|
|
int err;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
ipq_kill(qp);
|
|
|
|
|
2007-10-14 07:38:15 +00:00
|
|
|
/* Make the one we just received the head. */
|
|
|
|
if (prev) {
|
|
|
|
head = prev->next;
|
|
|
|
fp = skb_clone(head, GFP_ATOMIC);
|
|
|
|
|
|
|
|
if (!fp)
|
|
|
|
goto out_nomem;
|
|
|
|
|
|
|
|
fp->next = head->next;
|
|
|
|
prev->next = fp;
|
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
skb_morph(head, qp->q.fragments);
|
|
|
|
head->next = qp->q.fragments->next;
|
2007-10-14 07:38:15 +00:00
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
kfree_skb(qp->q.fragments);
|
|
|
|
qp->q.fragments = head;
|
2007-10-14 07:38:15 +00:00
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
BUG_TRAP(head != NULL);
|
|
|
|
BUG_TRAP(FRAG_CB(head)->offset == 0);
|
|
|
|
|
|
|
|
/* Allocate a new buffer for the datagram. */
|
2007-03-12 23:09:15 +00:00
|
|
|
ihlen = ip_hdrlen(head);
|
2007-10-15 09:24:19 +00:00
|
|
|
len = ihlen + qp->q.len;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-14 07:38:15 +00:00
|
|
|
err = -E2BIG;
|
2007-03-09 04:44:43 +00:00
|
|
|
if (len > 65535)
|
2005-04-16 22:20:36 +00:00
|
|
|
goto out_oversize;
|
|
|
|
|
|
|
|
/* Head of list must not be cloned. */
|
2007-10-14 07:38:15 +00:00
|
|
|
err = -ENOMEM;
|
2005-04-16 22:20:36 +00:00
|
|
|
if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
|
|
|
|
goto out_nomem;
|
|
|
|
|
|
|
|
/* If the first fragment is fragmented itself, we split
|
|
|
|
* it to two chunks: the first with data and paged part
|
|
|
|
* and the second, holding only fragments. */
|
|
|
|
if (skb_shinfo(head)->frag_list) {
|
|
|
|
struct sk_buff *clone;
|
|
|
|
int i, plen = 0;
|
|
|
|
|
|
|
|
if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
|
|
|
|
goto out_nomem;
|
|
|
|
clone->next = head->next;
|
|
|
|
head->next = clone;
|
|
|
|
skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
|
|
|
|
skb_shinfo(head)->frag_list = NULL;
|
|
|
|
for (i=0; i<skb_shinfo(head)->nr_frags; i++)
|
|
|
|
plen += skb_shinfo(head)->frags[i].size;
|
|
|
|
clone->len = clone->data_len = head->data_len - plen;
|
|
|
|
head->data_len -= clone->len;
|
|
|
|
head->len -= clone->len;
|
|
|
|
clone->csum = 0;
|
|
|
|
clone->ip_summed = head->ip_summed;
|
2007-10-15 09:31:52 +00:00
|
|
|
atomic_add(clone->truesize, &ip4_frags.mem);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
skb_shinfo(head)->frag_list = head->next;
|
2007-04-11 03:50:43 +00:00
|
|
|
skb_push(head, head->data - skb_network_header(head));
|
2007-10-15 09:31:52 +00:00
|
|
|
atomic_sub(head->truesize, &ip4_frags.mem);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
for (fp=head->next; fp; fp = fp->next) {
|
|
|
|
head->data_len += fp->len;
|
|
|
|
head->len += fp->len;
|
|
|
|
if (head->ip_summed != fp->ip_summed)
|
|
|
|
head->ip_summed = CHECKSUM_NONE;
|
2006-08-29 23:44:56 +00:00
|
|
|
else if (head->ip_summed == CHECKSUM_COMPLETE)
|
2005-04-16 22:20:36 +00:00
|
|
|
head->csum = csum_add(head->csum, fp->csum);
|
|
|
|
head->truesize += fp->truesize;
|
2007-10-15 09:31:52 +00:00
|
|
|
atomic_sub(fp->truesize, &ip4_frags.mem);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
head->next = NULL;
|
|
|
|
head->dev = dev;
|
2007-10-15 09:24:19 +00:00
|
|
|
head->tstamp = qp->q.stamp;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-04-21 05:47:35 +00:00
|
|
|
iph = ip_hdr(head);
|
2005-04-16 22:20:36 +00:00
|
|
|
iph->frag_off = 0;
|
|
|
|
iph->tot_len = htons(len);
|
|
|
|
IP_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
|
2007-10-15 09:24:19 +00:00
|
|
|
qp->q.fragments = NULL;
|
2007-10-14 07:38:15 +00:00
|
|
|
return 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
out_nomem:
|
2007-02-09 14:24:47 +00:00
|
|
|
LIMIT_NETDEBUG(KERN_ERR "IP: queue_glue: no memory for gluing "
|
2005-08-10 03:50:53 +00:00
|
|
|
"queue %p\n", qp);
|
2005-04-16 22:20:36 +00:00
|
|
|
goto out_fail;
|
|
|
|
out_oversize:
|
|
|
|
if (net_ratelimit())
|
|
|
|
printk(KERN_INFO
|
|
|
|
"Oversized IP packet from %d.%d.%d.%d.\n",
|
|
|
|
NIPQUAD(qp->saddr));
|
|
|
|
out_fail:
|
|
|
|
IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
|
2007-10-14 07:38:15 +00:00
|
|
|
return err;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Process an incoming IP datagram fragment. */
|
2007-10-14 07:38:32 +00:00
|
|
|
int ip_defrag(struct sk_buff *skb, u32 user)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct ipq *qp;
|
2007-02-09 14:24:47 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
IP_INC_STATS_BH(IPSTATS_MIB_REASMREQDS);
|
|
|
|
|
|
|
|
/* Start by cleaning up the memory. */
|
2007-10-15 09:33:45 +00:00
|
|
|
if (atomic_read(&ip4_frags.mem) > ip4_frags_ctl.high_thresh)
|
2005-04-16 22:20:36 +00:00
|
|
|
ip_evictor();
|
|
|
|
|
|
|
|
/* Lookup (or create) queue header */
|
2007-04-21 05:47:35 +00:00
|
|
|
if ((qp = ip_find(ip_hdr(skb), user)) != NULL) {
|
2007-10-14 07:38:15 +00:00
|
|
|
int ret;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
spin_lock(&qp->q.lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-14 07:38:15 +00:00
|
|
|
ret = ip_frag_queue(qp, skb);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-10-15 09:24:19 +00:00
|
|
|
spin_unlock(&qp->q.lock);
|
2007-10-15 09:41:09 +00:00
|
|
|
ipq_put(qp);
|
2007-10-14 07:38:32 +00:00
|
|
|
return ret;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
|
|
|
|
kfree_skb(skb);
|
2007-10-14 07:38:32 +00:00
|
|
|
return -ENOMEM;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-04-19 23:16:32 +00:00
|
|
|
void __init ipfrag_init(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-10-15 09:33:45 +00:00
|
|
|
ip4_frags.ctl = &ip4_frags_ctl;
|
2007-10-15 09:38:08 +00:00
|
|
|
ip4_frags.hashfn = ip4_hashfn;
|
2007-10-15 09:39:14 +00:00
|
|
|
ip4_frags.destructor = ip4_frag_free;
|
|
|
|
ip4_frags.skb_free = NULL;
|
|
|
|
ip4_frags.qsize = sizeof(struct ipq);
|
2007-10-15 09:31:52 +00:00
|
|
|
inet_frags_init(&ip4_frags);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
EXPORT_SYMBOL(ip_defrag);
|