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* Copyright (C)2004 USAGI/WIDE Project
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Author:
* Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
*
* 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
* - support Layer 3 protocol independent connection tracking.
* Based on the original ip_conntrack code which had the following
* copyright information:
* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
*
* 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
* - add get_features() to support various size of conntrack
* structures.
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/ipv6.h>
#include <linux/in6.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
#include <linux/sysctl.h>
#include <net/ipv6.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_protocol.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_core.h>
#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif
DECLARE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
static int ipv6_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
struct nf_conntrack_tuple *tuple)
{
u_int32_t _addrs[8], *ap;
ap = skb_header_pointer(skb, nhoff + offsetof(struct ipv6hdr, saddr),
sizeof(_addrs), _addrs);
if (ap == NULL)
return 0;
memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
return 1;
}
static int ipv6_invert_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_tuple *orig)
{
memcpy(tuple->src.u3.ip6, orig->dst.u3.ip6, sizeof(tuple->src.u3.ip6));
memcpy(tuple->dst.u3.ip6, orig->src.u3.ip6, sizeof(tuple->dst.u3.ip6));
return 1;
}
static int ipv6_print_tuple(struct seq_file *s,
const struct nf_conntrack_tuple *tuple)
{
return seq_printf(s, "src=" NIP6_FMT " dst=" NIP6_FMT " ",
NIP6(*((struct in6_addr *)tuple->src.u3.ip6)),
NIP6(*((struct in6_addr *)tuple->dst.u3.ip6)));
}
static int ipv6_print_conntrack(struct seq_file *s,
const struct nf_conn *conntrack)
{
return 0;
}
/*
* Based on ipv6_skip_exthdr() in net/ipv6/exthdr.c
*
* This function parses (probably truncated) exthdr set "hdr"
* of length "len". "nexthdrp" initially points to some place,
* where type of the first header can be found.
*
* It skips all well-known exthdrs, and returns pointer to the start
* of unparsable area i.e. the first header with unknown type.
* if success, *nexthdr is updated by type/protocol of this header.
*
* NOTES: - it may return pointer pointing beyond end of packet,
* if the last recognized header is truncated in the middle.
* - if packet is truncated, so that all parsed headers are skipped,
* it returns -1.
* - if packet is fragmented, return pointer of the fragment header.
* - ESP is unparsable for now and considered like
* normal payload protocol.
* - Note also special handling of AUTH header. Thanks to IPsec wizards.
*/
int nf_ct_ipv6_skip_exthdr(struct sk_buff *skb, int start, u8 *nexthdrp,
int len)
{
u8 nexthdr = *nexthdrp;
while (ipv6_ext_hdr(nexthdr)) {
struct ipv6_opt_hdr hdr;
int hdrlen;
if (len < (int)sizeof(struct ipv6_opt_hdr))
return -1;
if (nexthdr == NEXTHDR_NONE)
break;
if (nexthdr == NEXTHDR_FRAGMENT)
break;
if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
BUG();
if (nexthdr == NEXTHDR_AUTH)
hdrlen = (hdr.hdrlen+2)<<2;
else
hdrlen = ipv6_optlen(&hdr);
nexthdr = hdr.nexthdr;
len -= hdrlen;
start += hdrlen;
}
*nexthdrp = nexthdr;
return start;
}
static int
ipv6_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
u_int8_t *protonum)
{
unsigned int extoff;
unsigned char pnum;
int protoff;
extoff = (u8*)((*pskb)->nh.ipv6h + 1) - (*pskb)->data;
pnum = (*pskb)->nh.ipv6h->nexthdr;
protoff = nf_ct_ipv6_skip_exthdr(*pskb, extoff, &pnum,
(*pskb)->len - extoff);
/*
* (protoff == (*pskb)->len) mean that the packet doesn't have no data
* except of IPv6 & ext headers. but it's tracked anyway. - YK
*/
if ((protoff < 0) || (protoff > (*pskb)->len)) {
DEBUGP("ip6_conntrack_core: can't find proto in pkt\n");
NF_CT_STAT_INC(error);
NF_CT_STAT_INC(invalid);
return -NF_ACCEPT;
}
*dataoff = protoff;
*protonum = pnum;
return NF_ACCEPT;
}
static u_int32_t ipv6_get_features(const struct nf_conntrack_tuple *tuple)
{
return NF_CT_F_BASIC;
}
static unsigned int ipv6_confirm(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
/* This is where we call the helper: as the packet goes out. */
ct = nf_ct_get(*pskb, &ctinfo);
if (ct && ct->helper) {
unsigned int ret, protoff;
unsigned int extoff = (u8*)((*pskb)->nh.ipv6h + 1)
- (*pskb)->data;
unsigned char pnum = (*pskb)->nh.ipv6h->nexthdr;
protoff = nf_ct_ipv6_skip_exthdr(*pskb, extoff, &pnum,
(*pskb)->len - extoff);
if (protoff < 0 || protoff > (*pskb)->len ||
pnum == NEXTHDR_FRAGMENT) {
DEBUGP("proto header not found\n");
return NF_ACCEPT;
}
ret = ct->helper->help(pskb, protoff, ct, ctinfo);
if (ret != NF_ACCEPT)
return ret;
}
/* We've seen it coming out the other side: confirm it */
return nf_conntrack_confirm(pskb);
}
extern struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb);
extern void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
struct net_device *in,
struct net_device *out,
int (*okfn)(struct sk_buff *));
static unsigned int ipv6_defrag(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *reasm;
/* Previously seen (loopback)? */
if ((*pskb)->nfct)
return NF_ACCEPT;
reasm = nf_ct_frag6_gather(*pskb);
/* queued */
if (reasm == NULL)
return NF_STOLEN;
/* error occured or not fragmented */
if (reasm == *pskb)
return NF_ACCEPT;
nf_ct_frag6_output(hooknum, reasm, (struct net_device *)in,
(struct net_device *)out, okfn);
return NF_STOLEN;
}
static unsigned int ipv6_conntrack_in(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *reasm = (*pskb)->nfct_reasm;
/* This packet is fragmented and has reassembled packet. */
if (reasm) {
/* Reassembled packet isn't parsed yet ? */
if (!reasm->nfct) {
unsigned int ret;
ret = nf_conntrack_in(PF_INET6, hooknum, &reasm);
if (ret != NF_ACCEPT)
return ret;
}
nf_conntrack_get(reasm->nfct);
(*pskb)->nfct = reasm->nfct;
return NF_ACCEPT;
}
return nf_conntrack_in(PF_INET6, hooknum, pskb);
}
static unsigned int ipv6_conntrack_local(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
/* root is playing with raw sockets. */
if ((*pskb)->len < sizeof(struct ipv6hdr)) {
if (net_ratelimit())
printk("ipv6_conntrack_local: packet too short\n");
return NF_ACCEPT;
}
return ipv6_conntrack_in(hooknum, pskb, in, out, okfn);
}
/* Connection tracking may drop packets, but never alters them, so
make it the first hook. */
static struct nf_hook_ops ipv6_conntrack_defrag_ops = {
.hook = ipv6_defrag,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_IP6_PRE_ROUTING,
.priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
};
static struct nf_hook_ops ipv6_conntrack_in_ops = {
.hook = ipv6_conntrack_in,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_IP6_PRE_ROUTING,
.priority = NF_IP6_PRI_CONNTRACK,
};
static struct nf_hook_ops ipv6_conntrack_local_out_ops = {
.hook = ipv6_conntrack_local,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_IP6_LOCAL_OUT,
.priority = NF_IP6_PRI_CONNTRACK,
};
static struct nf_hook_ops ipv6_conntrack_defrag_local_out_ops = {
.hook = ipv6_defrag,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_IP6_LOCAL_OUT,
.priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
};
/* Refragmenter; last chance. */
static struct nf_hook_ops ipv6_conntrack_out_ops = {
.hook = ipv6_confirm,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_IP6_POST_ROUTING,
.priority = NF_IP6_PRI_LAST,
};
static struct nf_hook_ops ipv6_conntrack_local_in_ops = {
.hook = ipv6_confirm,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_IP6_LOCAL_IN,
.priority = NF_IP6_PRI_LAST-1,
};
#ifdef CONFIG_SYSCTL
/* From nf_conntrack_proto_icmpv6.c */
extern unsigned int nf_ct_icmpv6_timeout;
/* From nf_conntrack_frag6.c */
extern unsigned int nf_ct_frag6_timeout;
extern unsigned int nf_ct_frag6_low_thresh;
extern unsigned int nf_ct_frag6_high_thresh;
static struct ctl_table_header *nf_ct_ipv6_sysctl_header;
static ctl_table nf_ct_sysctl_table[] = {
{
.ctl_name = NET_NF_CONNTRACK_ICMPV6_TIMEOUT,
.procname = "nf_conntrack_icmpv6_timeout",
.data = &nf_ct_icmpv6_timeout,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = &proc_dointvec_jiffies,
},
{
.ctl_name = NET_NF_CONNTRACK_FRAG6_TIMEOUT,
.procname = "nf_conntrack_frag6_timeout",
.data = &nf_ct_frag6_timeout,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = &proc_dointvec_jiffies,
},
{
.ctl_name = NET_NF_CONNTRACK_FRAG6_LOW_THRESH,
.procname = "nf_conntrack_frag6_low_thresh",
.data = &nf_ct_frag6_low_thresh,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = NET_NF_CONNTRACK_FRAG6_HIGH_THRESH,
.procname = "nf_conntrack_frag6_high_thresh",
.data = &nf_ct_frag6_high_thresh,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
{ .ctl_name = 0 }
};
static ctl_table nf_ct_netfilter_table[] = {
{
.ctl_name = NET_NETFILTER,
.procname = "netfilter",
.mode = 0555,
.child = nf_ct_sysctl_table,
},
{ .ctl_name = 0 }
};
static ctl_table nf_ct_net_table[] = {
{
.ctl_name = CTL_NET,
.procname = "net",
.mode = 0555,
.child = nf_ct_netfilter_table,
},
{ .ctl_name = 0 }
};
#endif
#if defined(CONFIG_NF_CT_NETLINK) || \
defined(CONFIG_NF_CT_NETLINK_MODULE)
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
static int ipv6_tuple_to_nfattr(struct sk_buff *skb,
const struct nf_conntrack_tuple *tuple)
{
NFA_PUT(skb, CTA_IP_V6_SRC, sizeof(u_int32_t) * 4,
&tuple->src.u3.ip6);
NFA_PUT(skb, CTA_IP_V6_DST, sizeof(u_int32_t) * 4,
&tuple->dst.u3.ip6);
return 0;
nfattr_failure:
return -1;
}
static const size_t cta_min_ip[CTA_IP_MAX] = {
[CTA_IP_V6_SRC-1] = sizeof(u_int32_t)*4,
[CTA_IP_V6_DST-1] = sizeof(u_int32_t)*4,
};
static int ipv6_nfattr_to_tuple(struct nfattr *tb[],
struct nf_conntrack_tuple *t)
{
if (!tb[CTA_IP_V6_SRC-1] || !tb[CTA_IP_V6_DST-1])
return -EINVAL;
if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
return -EINVAL;
memcpy(&t->src.u3.ip6, NFA_DATA(tb[CTA_IP_V6_SRC-1]),
sizeof(u_int32_t) * 4);
memcpy(&t->dst.u3.ip6, NFA_DATA(tb[CTA_IP_V6_DST-1]),
sizeof(u_int32_t) * 4);
return 0;
}
#endif
struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 = {
.l3proto = PF_INET6,
.name = "ipv6",
.pkt_to_tuple = ipv6_pkt_to_tuple,
.invert_tuple = ipv6_invert_tuple,
.print_tuple = ipv6_print_tuple,
.print_conntrack = ipv6_print_conntrack,
.prepare = ipv6_prepare,
#if defined(CONFIG_NF_CT_NETLINK) || \
defined(CONFIG_NF_CT_NETLINK_MODULE)
.tuple_to_nfattr = ipv6_tuple_to_nfattr,
.nfattr_to_tuple = ipv6_nfattr_to_tuple,
#endif
.get_features = ipv6_get_features,
.me = THIS_MODULE,
};
extern struct nf_conntrack_protocol nf_conntrack_protocol_tcp6;
extern struct nf_conntrack_protocol nf_conntrack_protocol_udp6;
extern struct nf_conntrack_protocol nf_conntrack_protocol_icmpv6;
extern int nf_ct_frag6_init(void);
extern void nf_ct_frag6_cleanup(void);
static int init_or_cleanup(int init)
{
int ret = 0;
if (!init) goto cleanup;
ret = nf_ct_frag6_init();
if (ret < 0) {
printk("nf_conntrack_ipv6: can't initialize frag6.\n");
goto cleanup_nothing;
}
ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_tcp6);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register tcp.\n");
goto cleanup_frag6;
}
ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_udp6);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register udp.\n");
goto cleanup_tcp;
}
ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_icmpv6);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register icmpv6.\n");
goto cleanup_udp;
}
ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv6);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register ipv6\n");
goto cleanup_icmpv6;
}
ret = nf_register_hook(&ipv6_conntrack_defrag_ops);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register pre-routing defrag "
"hook.\n");
goto cleanup_ipv6;
}
ret = nf_register_hook(&ipv6_conntrack_defrag_local_out_ops);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register local_out defrag "
"hook.\n");
goto cleanup_defragops;
}
ret = nf_register_hook(&ipv6_conntrack_in_ops);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register pre-routing hook.\n");
goto cleanup_defraglocalops;
}
ret = nf_register_hook(&ipv6_conntrack_local_out_ops);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register local out hook.\n");
goto cleanup_inops;
}
ret = nf_register_hook(&ipv6_conntrack_out_ops);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register post-routing hook.\n");
goto cleanup_inandlocalops;
}
ret = nf_register_hook(&ipv6_conntrack_local_in_ops);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register local in hook.\n");
goto cleanup_inoutandlocalops;
}
#ifdef CONFIG_SYSCTL
nf_ct_ipv6_sysctl_header = register_sysctl_table(nf_ct_net_table, 0);
if (nf_ct_ipv6_sysctl_header == NULL) {
printk("nf_conntrack: can't register to sysctl.\n");
ret = -ENOMEM;
goto cleanup_localinops;
}
#endif
return ret;
cleanup:
synchronize_net();
#ifdef CONFIG_SYSCTL
unregister_sysctl_table(nf_ct_ipv6_sysctl_header);
cleanup_localinops:
#endif
nf_unregister_hook(&ipv6_conntrack_local_in_ops);
cleanup_inoutandlocalops:
nf_unregister_hook(&ipv6_conntrack_out_ops);
cleanup_inandlocalops:
nf_unregister_hook(&ipv6_conntrack_local_out_ops);
cleanup_inops:
nf_unregister_hook(&ipv6_conntrack_in_ops);
cleanup_defraglocalops:
nf_unregister_hook(&ipv6_conntrack_defrag_local_out_ops);
cleanup_defragops:
nf_unregister_hook(&ipv6_conntrack_defrag_ops);
cleanup_ipv6:
nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6);
cleanup_icmpv6:
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmpv6);
cleanup_udp:
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp6);
cleanup_tcp:
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp6);
cleanup_frag6:
nf_ct_frag6_cleanup();
cleanup_nothing:
return ret;
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Yasuyuki KOZAKAI @USAGI <yasuyuki.kozakai@toshiba.co.jp>");
static int __init init(void)
{
need_conntrack();
return init_or_cleanup(1);
}
static void __exit fini(void)
{
init_or_cleanup(0);
}
module_init(init);
module_exit(fini);
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