![Justin P. Mattock](/assets/img/avatar_default.png)
The below patch fixes some typos in various parts of the kernel, as well as fixes some comments. Please let me know if I missed anything, and I will try to get it changed and resent. Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
873 lines
21 KiB
C
873 lines
21 KiB
C
/*
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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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*
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* Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG>
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* Alan Cox <alan@lxorguk.ukuu.org.uk>
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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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#include <linux/compiler.h>
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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 <linux/slab.h>
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#include <net/route.h>
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#include <net/dst.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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#include <net/inetpeer.h>
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#include <net/inet_frag.h>
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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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#include <net/inet_ecn.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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static int sysctl_ipfrag_max_dist __read_mostly = 64;
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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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struct inet_frag_queue q;
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u32 user;
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__be32 saddr;
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__be32 daddr;
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__be16 id;
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u8 protocol;
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u8 ecn; /* RFC3168 support */
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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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};
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/* RFC 3168 support :
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* We want to check ECN values of all fragments, do detect invalid combinations.
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* In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
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*/
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#define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */
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#define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */
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#define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */
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#define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */
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static inline u8 ip4_frag_ecn(u8 tos)
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{
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return 1 << (tos & INET_ECN_MASK);
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}
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/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
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* Value : 0xff if frame should be dropped.
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* 0 or INET_ECN_CE value, to be ORed in to final iph->tos field
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*/
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static const u8 ip4_frag_ecn_table[16] = {
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/* at least one fragment had CE, and others ECT_0 or ECT_1 */
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[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = INET_ECN_CE,
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[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = INET_ECN_CE,
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[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = INET_ECN_CE,
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/* invalid combinations : drop frame */
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff,
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[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
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};
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static struct inet_frags ip4_frags;
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int ip_frag_nqueues(struct net *net)
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{
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return net->ipv4.frags.nqueues;
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}
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int ip_frag_mem(struct net *net)
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{
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return atomic_read(&net->ipv4.frags.mem);
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}
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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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struct ip4_create_arg {
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struct iphdr *iph;
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u32 user;
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};
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static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot)
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{
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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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ip4_frags.rnd) & (INETFRAGS_HASHSZ - 1);
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}
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static unsigned int ip4_hashfn(struct inet_frag_queue *q)
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{
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struct ipq *ipq;
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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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}
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static int ip4_frag_match(struct inet_frag_queue *q, void *a)
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{
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struct ipq *qp;
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struct ip4_create_arg *arg = a;
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qp = container_of(q, struct ipq, q);
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return qp->id == arg->iph->id &&
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qp->saddr == arg->iph->saddr &&
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qp->daddr == arg->iph->daddr &&
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qp->protocol == arg->iph->protocol &&
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qp->user == arg->user;
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}
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/* Memory Tracking Functions. */
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static void frag_kfree_skb(struct netns_frags *nf, struct sk_buff *skb)
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{
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atomic_sub(skb->truesize, &nf->mem);
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kfree_skb(skb);
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}
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static void ip4_frag_init(struct inet_frag_queue *q, void *a)
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{
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struct ipq *qp = container_of(q, struct ipq, q);
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struct ip4_create_arg *arg = a;
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qp->protocol = arg->iph->protocol;
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qp->id = arg->iph->id;
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qp->ecn = ip4_frag_ecn(arg->iph->tos);
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qp->saddr = arg->iph->saddr;
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qp->daddr = arg->iph->daddr;
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qp->user = arg->user;
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qp->peer = sysctl_ipfrag_max_dist ?
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inet_getpeer_v4(arg->iph->saddr, 1) : NULL;
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}
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static __inline__ void ip4_frag_free(struct inet_frag_queue *q)
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{
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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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}
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/* Destruction primitives. */
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static __inline__ void ipq_put(struct ipq *ipq)
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{
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inet_frag_put(&ipq->q, &ip4_frags);
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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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inet_frag_kill(&ipq->q, &ip4_frags);
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}
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/* Memory limiting on fragments. Evictor trashes the oldest
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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(struct net *net)
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{
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int evicted;
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evicted = inet_frag_evictor(&net->ipv4.frags, &ip4_frags);
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if (evicted)
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IP_ADD_STATS_BH(net, IPSTATS_MIB_REASMFAILS, evicted);
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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;
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struct net *net;
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qp = container_of((struct inet_frag_queue *) arg, struct ipq, q);
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net = container_of(qp->q.net, struct net, ipv4.frags);
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spin_lock(&qp->q.lock);
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if (qp->q.last_in & INET_FRAG_COMPLETE)
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goto out;
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ipq_kill(qp);
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IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT);
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IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
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if ((qp->q.last_in & INET_FRAG_FIRST_IN) && qp->q.fragments != NULL) {
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struct sk_buff *head = qp->q.fragments;
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const struct iphdr *iph;
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int err;
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rcu_read_lock();
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head->dev = dev_get_by_index_rcu(net, qp->iif);
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if (!head->dev)
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goto out_rcu_unlock;
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/* skb dst is stale, drop it, and perform route lookup again */
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skb_dst_drop(head);
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iph = ip_hdr(head);
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err = ip_route_input_noref(head, iph->daddr, iph->saddr,
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iph->tos, head->dev);
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if (err)
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goto out_rcu_unlock;
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/*
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* Only an end host needs to send an ICMP
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* "Fragment Reassembly Timeout" message, per RFC792.
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*/
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if (qp->user == IP_DEFRAG_AF_PACKET ||
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(qp->user == IP_DEFRAG_CONNTRACK_IN &&
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skb_rtable(head)->rt_type != RTN_LOCAL))
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goto out_rcu_unlock;
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/* Send an ICMP "Fragment Reassembly Timeout" message. */
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icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
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out_rcu_unlock:
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rcu_read_unlock();
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}
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out:
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spin_unlock(&qp->q.lock);
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ipq_put(qp);
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}
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/* Find the correct entry in the "incomplete datagrams" queue for
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* this IP datagram, and create new one, if nothing is found.
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*/
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static inline struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user)
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{
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struct inet_frag_queue *q;
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struct ip4_create_arg arg;
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unsigned int hash;
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arg.iph = iph;
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arg.user = user;
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read_lock(&ip4_frags.lock);
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hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol);
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q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash);
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if (q == NULL)
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goto out_nomem;
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return container_of(q, struct ipq, q);
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out_nomem:
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LIMIT_NETDEBUG(KERN_ERR "ip_frag_create: no memory left !\n");
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return NULL;
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}
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/* Is the fragment too far ahead to be part of ipq? */
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static inline int ip_frag_too_far(struct ipq *qp)
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{
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struct inet_peer *peer = qp->peer;
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unsigned int max = sysctl_ipfrag_max_dist;
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unsigned int start, end;
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int rc;
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if (!peer || !max)
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return 0;
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start = qp->rid;
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end = atomic_inc_return(&peer->rid);
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qp->rid = end;
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rc = qp->q.fragments && (end - start) > max;
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if (rc) {
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struct net *net;
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net = container_of(qp->q.net, struct net, ipv4.frags);
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IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
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}
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return rc;
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}
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static int ip_frag_reinit(struct ipq *qp)
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{
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struct sk_buff *fp;
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if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) {
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atomic_inc(&qp->q.refcnt);
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return -ETIMEDOUT;
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}
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fp = qp->q.fragments;
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do {
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struct sk_buff *xp = fp->next;
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frag_kfree_skb(qp->q.net, fp);
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fp = xp;
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} while (fp);
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qp->q.last_in = 0;
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qp->q.len = 0;
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qp->q.meat = 0;
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qp->q.fragments = NULL;
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qp->q.fragments_tail = NULL;
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qp->iif = 0;
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qp->ecn = 0;
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return 0;
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}
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/* Add new segment to existing queue. */
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static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
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{
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struct sk_buff *prev, *next;
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struct net_device *dev;
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int flags, offset;
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int ihl, end;
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int err = -ENOENT;
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u8 ecn;
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if (qp->q.last_in & INET_FRAG_COMPLETE)
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goto err;
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if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
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unlikely(ip_frag_too_far(qp)) &&
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unlikely(err = ip_frag_reinit(qp))) {
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ipq_kill(qp);
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goto err;
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}
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ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
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offset = ntohs(ip_hdr(skb)->frag_off);
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flags = offset & ~IP_OFFSET;
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offset &= IP_OFFSET;
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offset <<= 3; /* offset is in 8-byte chunks */
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ihl = ip_hdrlen(skb);
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/* Determine the position of this fragment. */
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end = offset + skb->len - ihl;
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err = -EINVAL;
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/* Is this the final fragment? */
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if ((flags & IP_MF) == 0) {
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/* If we already have some bits beyond end
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* or have different end, the segment is corrupted.
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*/
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if (end < qp->q.len ||
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((qp->q.last_in & INET_FRAG_LAST_IN) && end != qp->q.len))
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goto err;
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qp->q.last_in |= INET_FRAG_LAST_IN;
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qp->q.len = end;
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} else {
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if (end&7) {
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end &= ~7;
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if (skb->ip_summed != CHECKSUM_UNNECESSARY)
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skb->ip_summed = CHECKSUM_NONE;
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}
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if (end > qp->q.len) {
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/* Some bits beyond end -> corruption. */
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if (qp->q.last_in & INET_FRAG_LAST_IN)
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goto err;
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qp->q.len = end;
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}
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}
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if (end == offset)
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goto err;
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err = -ENOMEM;
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if (pskb_pull(skb, ihl) == NULL)
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goto err;
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err = pskb_trim_rcsum(skb, end - offset);
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if (err)
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goto err;
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/* Find out which fragments are in front and at the back of us
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* in the chain of fragments so far. We must know where to put
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* this fragment, right?
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*/
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prev = qp->q.fragments_tail;
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if (!prev || FRAG_CB(prev)->offset < offset) {
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next = NULL;
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goto found;
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}
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prev = NULL;
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for (next = qp->q.fragments; next != NULL; next = next->next) {
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if (FRAG_CB(next)->offset >= offset)
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break; /* bingo! */
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prev = next;
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}
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found:
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/* We found where to put this one. Check for overlap with
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* preceding fragment, and, if needed, align things so that
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* any overlaps are eliminated.
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*/
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if (prev) {
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int i = (FRAG_CB(prev)->offset + prev->len) - offset;
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if (i > 0) {
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offset += i;
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err = -EINVAL;
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if (end <= offset)
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goto err;
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err = -ENOMEM;
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if (!pskb_pull(skb, i))
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goto err;
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if (skb->ip_summed != CHECKSUM_UNNECESSARY)
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skb->ip_summed = CHECKSUM_NONE;
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}
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}
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err = -ENOMEM;
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while (next && FRAG_CB(next)->offset < end) {
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int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */
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if (i < next->len) {
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/* Eat head of the next overlapped fragment
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* and leave the loop. The next ones cannot overlap.
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*/
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if (!pskb_pull(next, i))
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goto err;
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FRAG_CB(next)->offset += i;
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qp->q.meat -= i;
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if (next->ip_summed != CHECKSUM_UNNECESSARY)
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next->ip_summed = CHECKSUM_NONE;
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break;
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} else {
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struct sk_buff *free_it = next;
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/* Old fragment is completely overridden with
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* new one drop it.
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*/
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next = next->next;
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if (prev)
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prev->next = next;
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else
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qp->q.fragments = next;
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qp->q.meat -= free_it->len;
|
|
frag_kfree_skb(qp->q.net, free_it);
|
|
}
|
|
}
|
|
|
|
FRAG_CB(skb)->offset = offset;
|
|
|
|
/* Insert this fragment in the chain of fragments. */
|
|
skb->next = next;
|
|
if (!next)
|
|
qp->q.fragments_tail = skb;
|
|
if (prev)
|
|
prev->next = skb;
|
|
else
|
|
qp->q.fragments = skb;
|
|
|
|
dev = skb->dev;
|
|
if (dev) {
|
|
qp->iif = dev->ifindex;
|
|
skb->dev = NULL;
|
|
}
|
|
qp->q.stamp = skb->tstamp;
|
|
qp->q.meat += skb->len;
|
|
qp->ecn |= ecn;
|
|
atomic_add(skb->truesize, &qp->q.net->mem);
|
|
if (offset == 0)
|
|
qp->q.last_in |= INET_FRAG_FIRST_IN;
|
|
|
|
if (qp->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
|
|
qp->q.meat == qp->q.len)
|
|
return ip_frag_reasm(qp, prev, dev);
|
|
|
|
write_lock(&ip4_frags.lock);
|
|
list_move_tail(&qp->q.lru_list, &qp->q.net->lru_list);
|
|
write_unlock(&ip4_frags.lock);
|
|
return -EINPROGRESS;
|
|
|
|
err:
|
|
kfree_skb(skb);
|
|
return err;
|
|
}
|
|
|
|
|
|
/* Build a new IP datagram from all its fragments. */
|
|
|
|
static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
|
|
struct net_device *dev)
|
|
{
|
|
struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
|
|
struct iphdr *iph;
|
|
struct sk_buff *fp, *head = qp->q.fragments;
|
|
int len;
|
|
int ihlen;
|
|
int err;
|
|
u8 ecn;
|
|
|
|
ipq_kill(qp);
|
|
|
|
ecn = ip4_frag_ecn_table[qp->ecn];
|
|
if (unlikely(ecn == 0xff)) {
|
|
err = -EINVAL;
|
|
goto out_fail;
|
|
}
|
|
/* 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;
|
|
if (!fp->next)
|
|
qp->q.fragments_tail = fp;
|
|
prev->next = fp;
|
|
|
|
skb_morph(head, qp->q.fragments);
|
|
head->next = qp->q.fragments->next;
|
|
|
|
kfree_skb(qp->q.fragments);
|
|
qp->q.fragments = head;
|
|
}
|
|
|
|
WARN_ON(head == NULL);
|
|
WARN_ON(FRAG_CB(head)->offset != 0);
|
|
|
|
/* Allocate a new buffer for the datagram. */
|
|
ihlen = ip_hdrlen(head);
|
|
len = ihlen + qp->q.len;
|
|
|
|
err = -E2BIG;
|
|
if (len > 65535)
|
|
goto out_oversize;
|
|
|
|
/* Head of list must not be cloned. */
|
|
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_has_frag_list(head)) {
|
|
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_frag_list_init(head);
|
|
for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
|
|
plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
|
|
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;
|
|
atomic_add(clone->truesize, &qp->q.net->mem);
|
|
}
|
|
|
|
skb_shinfo(head)->frag_list = head->next;
|
|
skb_push(head, head->data - skb_network_header(head));
|
|
|
|
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;
|
|
else if (head->ip_summed == CHECKSUM_COMPLETE)
|
|
head->csum = csum_add(head->csum, fp->csum);
|
|
head->truesize += fp->truesize;
|
|
}
|
|
atomic_sub(head->truesize, &qp->q.net->mem);
|
|
|
|
head->next = NULL;
|
|
head->dev = dev;
|
|
head->tstamp = qp->q.stamp;
|
|
|
|
iph = ip_hdr(head);
|
|
iph->frag_off = 0;
|
|
iph->tot_len = htons(len);
|
|
iph->tos |= ecn;
|
|
IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS);
|
|
qp->q.fragments = NULL;
|
|
qp->q.fragments_tail = NULL;
|
|
return 0;
|
|
|
|
out_nomem:
|
|
LIMIT_NETDEBUG(KERN_ERR "IP: queue_glue: no memory for gluing "
|
|
"queue %p\n", qp);
|
|
err = -ENOMEM;
|
|
goto out_fail;
|
|
out_oversize:
|
|
if (net_ratelimit())
|
|
printk(KERN_INFO "Oversized IP packet from %pI4.\n",
|
|
&qp->saddr);
|
|
out_fail:
|
|
IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
|
|
return err;
|
|
}
|
|
|
|
/* Process an incoming IP datagram fragment. */
|
|
int ip_defrag(struct sk_buff *skb, u32 user)
|
|
{
|
|
struct ipq *qp;
|
|
struct net *net;
|
|
|
|
net = skb->dev ? dev_net(skb->dev) : dev_net(skb_dst(skb)->dev);
|
|
IP_INC_STATS_BH(net, IPSTATS_MIB_REASMREQDS);
|
|
|
|
/* Start by cleaning up the memory. */
|
|
if (atomic_read(&net->ipv4.frags.mem) > net->ipv4.frags.high_thresh)
|
|
ip_evictor(net);
|
|
|
|
/* Lookup (or create) queue header */
|
|
if ((qp = ip_find(net, ip_hdr(skb), user)) != NULL) {
|
|
int ret;
|
|
|
|
spin_lock(&qp->q.lock);
|
|
|
|
ret = ip_frag_queue(qp, skb);
|
|
|
|
spin_unlock(&qp->q.lock);
|
|
ipq_put(qp);
|
|
return ret;
|
|
}
|
|
|
|
IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
|
|
kfree_skb(skb);
|
|
return -ENOMEM;
|
|
}
|
|
EXPORT_SYMBOL(ip_defrag);
|
|
|
|
struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
|
|
{
|
|
const struct iphdr *iph;
|
|
u32 len;
|
|
|
|
if (skb->protocol != htons(ETH_P_IP))
|
|
return skb;
|
|
|
|
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
|
|
return skb;
|
|
|
|
iph = ip_hdr(skb);
|
|
if (iph->ihl < 5 || iph->version != 4)
|
|
return skb;
|
|
if (!pskb_may_pull(skb, iph->ihl*4))
|
|
return skb;
|
|
iph = ip_hdr(skb);
|
|
len = ntohs(iph->tot_len);
|
|
if (skb->len < len || len < (iph->ihl * 4))
|
|
return skb;
|
|
|
|
if (ip_is_fragment(ip_hdr(skb))) {
|
|
skb = skb_share_check(skb, GFP_ATOMIC);
|
|
if (skb) {
|
|
if (pskb_trim_rcsum(skb, len))
|
|
return skb;
|
|
memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
|
|
if (ip_defrag(skb, user))
|
|
return NULL;
|
|
skb->rxhash = 0;
|
|
}
|
|
}
|
|
return skb;
|
|
}
|
|
EXPORT_SYMBOL(ip_check_defrag);
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
static int zero;
|
|
|
|
static struct ctl_table ip4_frags_ns_ctl_table[] = {
|
|
{
|
|
.procname = "ipfrag_high_thresh",
|
|
.data = &init_net.ipv4.frags.high_thresh,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec
|
|
},
|
|
{
|
|
.procname = "ipfrag_low_thresh",
|
|
.data = &init_net.ipv4.frags.low_thresh,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec
|
|
},
|
|
{
|
|
.procname = "ipfrag_time",
|
|
.data = &init_net.ipv4.frags.timeout,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{ }
|
|
};
|
|
|
|
static struct ctl_table ip4_frags_ctl_table[] = {
|
|
{
|
|
.procname = "ipfrag_secret_interval",
|
|
.data = &ip4_frags.secret_interval,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{
|
|
.procname = "ipfrag_max_dist",
|
|
.data = &sysctl_ipfrag_max_dist,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_minmax,
|
|
.extra1 = &zero
|
|
},
|
|
{ }
|
|
};
|
|
|
|
static int __net_init ip4_frags_ns_ctl_register(struct net *net)
|
|
{
|
|
struct ctl_table *table;
|
|
struct ctl_table_header *hdr;
|
|
|
|
table = ip4_frags_ns_ctl_table;
|
|
if (!net_eq(net, &init_net)) {
|
|
table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL);
|
|
if (table == NULL)
|
|
goto err_alloc;
|
|
|
|
table[0].data = &net->ipv4.frags.high_thresh;
|
|
table[1].data = &net->ipv4.frags.low_thresh;
|
|
table[2].data = &net->ipv4.frags.timeout;
|
|
}
|
|
|
|
hdr = register_net_sysctl_table(net, net_ipv4_ctl_path, table);
|
|
if (hdr == NULL)
|
|
goto err_reg;
|
|
|
|
net->ipv4.frags_hdr = hdr;
|
|
return 0;
|
|
|
|
err_reg:
|
|
if (!net_eq(net, &init_net))
|
|
kfree(table);
|
|
err_alloc:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net)
|
|
{
|
|
struct ctl_table *table;
|
|
|
|
table = net->ipv4.frags_hdr->ctl_table_arg;
|
|
unregister_net_sysctl_table(net->ipv4.frags_hdr);
|
|
kfree(table);
|
|
}
|
|
|
|
static void ip4_frags_ctl_register(void)
|
|
{
|
|
register_net_sysctl_rotable(net_ipv4_ctl_path, ip4_frags_ctl_table);
|
|
}
|
|
#else
|
|
static inline int ip4_frags_ns_ctl_register(struct net *net)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void ip4_frags_ns_ctl_unregister(struct net *net)
|
|
{
|
|
}
|
|
|
|
static inline void ip4_frags_ctl_register(void)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
static int __net_init ipv4_frags_init_net(struct net *net)
|
|
{
|
|
/*
|
|
* Fragment cache limits. We will commit 256K at one time. Should we
|
|
* cross that limit we will prune down to 192K. This should cope with
|
|
* even the most extreme cases without allowing an attacker to
|
|
* measurably harm machine performance.
|
|
*/
|
|
net->ipv4.frags.high_thresh = 256 * 1024;
|
|
net->ipv4.frags.low_thresh = 192 * 1024;
|
|
/*
|
|
* Important NOTE! Fragment queue must be destroyed before MSL expires.
|
|
* RFC791 is wrong proposing to prolongate timer each fragment arrival
|
|
* by TTL.
|
|
*/
|
|
net->ipv4.frags.timeout = IP_FRAG_TIME;
|
|
|
|
inet_frags_init_net(&net->ipv4.frags);
|
|
|
|
return ip4_frags_ns_ctl_register(net);
|
|
}
|
|
|
|
static void __net_exit ipv4_frags_exit_net(struct net *net)
|
|
{
|
|
ip4_frags_ns_ctl_unregister(net);
|
|
inet_frags_exit_net(&net->ipv4.frags, &ip4_frags);
|
|
}
|
|
|
|
static struct pernet_operations ip4_frags_ops = {
|
|
.init = ipv4_frags_init_net,
|
|
.exit = ipv4_frags_exit_net,
|
|
};
|
|
|
|
void __init ipfrag_init(void)
|
|
{
|
|
ip4_frags_ctl_register();
|
|
register_pernet_subsys(&ip4_frags_ops);
|
|
ip4_frags.hashfn = ip4_hashfn;
|
|
ip4_frags.constructor = ip4_frag_init;
|
|
ip4_frags.destructor = ip4_frag_free;
|
|
ip4_frags.skb_free = NULL;
|
|
ip4_frags.qsize = sizeof(struct ipq);
|
|
ip4_frags.match = ip4_frag_match;
|
|
ip4_frags.frag_expire = ip_expire;
|
|
ip4_frags.secret_interval = 10 * 60 * HZ;
|
|
inet_frags_init(&ip4_frags);
|
|
}
|