/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
*
* 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.
*
* 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
* - move L3 protocol dependent part to this file.
* 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
* - add get_features() to support various size of conntrack
* structures.
*
* Derived from net/ipv4/netfilter/ip_conntrack_standalone.c
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/ip.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
#include <linux/sysctl.h>
#include <net/route.h>
#include <net/ip.h>
#include <linux/netfilter_ipv4.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>
#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif
DECLARE_PER_CPU(struct nf_conntrack_stat, nf_conntrack_stat);
static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
struct nf_conntrack_tuple *tuple)
{
u_int32_t _addrs[2], *ap;
ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
sizeof(u_int32_t) * 2, _addrs);
if (ap == NULL)
return 0;
tuple->src.u3.ip = ap[0];
tuple->dst.u3.ip = ap[1];
return 1;
}
static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_tuple *orig)
{
tuple->src.u3.ip = orig->dst.u3.ip;
tuple->dst.u3.ip = orig->src.u3.ip;
return 1;
}
static int ipv4_print_tuple(struct seq_file *s,
const struct nf_conntrack_tuple *tuple)
{
return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
NIPQUAD(tuple->src.u3.ip),
NIPQUAD(tuple->dst.u3.ip));
}
static int ipv4_print_conntrack(struct seq_file *s,
const struct nf_conn *conntrack)
{
return 0;
}
/* Returns new sk_buff, or NULL */
static struct sk_buff *
nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
{
skb_orphan(skb);
local_bh_disable();
skb = ip_defrag(skb, user);
local_bh_enable();
if (skb)
ip_send_check(skb->nh.iph);
return skb;
}
static int
ipv4_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
u_int8_t *protonum)
{
/* Never happen */
if ((*pskb)->nh.iph->frag_off & htons(IP_OFFSET)) {
if (net_ratelimit()) {
printk(KERN_ERR "ipv4_prepare: Frag of proto %u (hook=%u)\n",
(*pskb)->nh.iph->protocol, hooknum);
}
return -NF_DROP;
}
*dataoff = (*pskb)->nh.raw - (*pskb)->data + (*pskb)->nh.iph->ihl*4;
*protonum = (*pskb)->nh.iph->protocol;
return NF_ACCEPT;
}
int nat_module_is_loaded = 0;
static u_int32_t ipv4_get_features(const struct nf_conntrack_tuple *tuple)
{
if (nat_module_is_loaded)
return NF_CT_F_NAT;
return NF_CT_F_BASIC;
}
static unsigned int ipv4_confirm(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
/* We've seen it coming out the other side: confirm it */
return nf_conntrack_confirm(pskb);
}
static unsigned int ipv4_conntrack_help(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;
struct nf_conn_help *help;
/* This is where we call the helper: as the packet goes out. */
ct = nf_ct_get(*pskb, &ctinfo);
if (!ct)
return NF_ACCEPT;
help = nfct_help(ct);
if (!help || !help->helper)
return NF_ACCEPT;
return help->helper->help(pskb,
(*pskb)->nh.raw - (*pskb)->data
+ (*pskb)->nh.iph->ihl*4,
ct, ctinfo);
}
static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
#if !defined(CONFIG_IP_NF_NAT) && !defined(CONFIG_IP_NF_NAT_MODULE)
/* Previously seen (loopback)? Ignore. Do this before
fragment check. */
if ((*pskb)->nfct)
return NF_ACCEPT;
#endif
/* Gather fragments. */
if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
*pskb = nf_ct_ipv4_gather_frags(*pskb,
hooknum == NF_IP_PRE_ROUTING ?
IP_DEFRAG_CONNTRACK_IN :
IP_DEFRAG_CONNTRACK_OUT);
if (!*pskb)
return NF_STOLEN;
}
return NF_ACCEPT;
}
static unsigned int ipv4_conntrack_in(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
return nf_conntrack_in(PF_INET, hooknum, pskb);
}
static unsigned int ipv4_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 iphdr)
|| (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {
if (net_ratelimit())
printk("ipt_hook: happy cracking.\n");
return NF_ACCEPT;
}
return nf_conntrack_in(PF_INET, hooknum, pskb);
}
/* Connection tracking may drop packets, but never alters them, so
make it the first hook. */
static struct nf_hook_ops ipv4_conntrack_defrag_ops = {
.hook = ipv4_conntrack_defrag,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_PRE_ROUTING,
.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
};
static struct nf_hook_ops ipv4_conntrack_in_ops = {
.hook = ipv4_conntrack_in,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_PRE_ROUTING,
.priority = NF_IP_PRI_CONNTRACK,
};
static struct nf_hook_ops ipv4_conntrack_defrag_local_out_ops = {
.hook = ipv4_conntrack_defrag,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_LOCAL_OUT,
.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
};
static struct nf_hook_ops ipv4_conntrack_local_out_ops = {
.hook = ipv4_conntrack_local,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_LOCAL_OUT,
.priority = NF_IP_PRI_CONNTRACK,
};
/* helpers */
static struct nf_hook_ops ipv4_conntrack_helper_out_ops = {
.hook = ipv4_conntrack_help,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_POST_ROUTING,
.priority = NF_IP_PRI_CONNTRACK_HELPER,
};
static struct nf_hook_ops ipv4_conntrack_helper_in_ops = {
.hook = ipv4_conntrack_help,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_LOCAL_IN,
.priority = NF_IP_PRI_CONNTRACK_HELPER,
};
/* Refragmenter; last chance. */
static struct nf_hook_ops ipv4_conntrack_out_ops = {
.hook = ipv4_confirm,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_POST_ROUTING,
.priority = NF_IP_PRI_CONNTRACK_CONFIRM,
};
static struct nf_hook_ops ipv4_conntrack_local_in_ops = {
.hook = ipv4_confirm,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_LOCAL_IN,
.priority = NF_IP_PRI_CONNTRACK_CONFIRM,
};
#ifdef CONFIG_SYSCTL
/* From nf_conntrack_proto_icmp.c */
extern unsigned int nf_ct_icmp_timeout;
static struct ctl_table_header *nf_ct_ipv4_sysctl_header;
static ctl_table nf_ct_sysctl_table[] = {
{
.ctl_name = NET_NF_CONNTRACK_ICMP_TIMEOUT,
.procname = "nf_conntrack_icmp_timeout",
.data = &nf_ct_icmp_timeout,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = &proc_dointvec_jiffies,
},
{ .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
/* Fast function for those who don't want to parse /proc (and I don't
blame them). */
/* Reversing the socket's dst/src point of view gives us the reply
mapping. */
static int
getorigdst(struct sock *sk, int optval, void __user *user, int *len)
{
struct inet_sock *inet = inet_sk(sk);
struct nf_conntrack_tuple_hash *h;
struct nf_conntrack_tuple tuple;
NF_CT_TUPLE_U_BLANK(&tuple);
tuple.src.u3.ip = inet->rcv_saddr;
tuple.src.u.tcp.port = inet->sport;
tuple.dst.u3.ip = inet->daddr;
tuple.dst.u.tcp.port = inet->dport;
tuple.src.l3num = PF_INET;
tuple.dst.protonum = IPPROTO_TCP;
/* We only do TCP at the moment: is there a better way? */
if (strcmp(sk->sk_prot->name, "TCP")) {
DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
return -ENOPROTOOPT;
}
if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
*len, sizeof(struct sockaddr_in));
return -EINVAL;
}
h = nf_conntrack_find_get(&tuple, NULL);
if (h) {
struct sockaddr_in sin;
struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
sin.sin_family = AF_INET;
sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
.tuple.dst.u.tcp.port;
sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
.tuple.dst.u3.ip;
DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
nf_ct_put(ct);
if (copy_to_user(user, &sin, sizeof(sin)) != 0)
return -EFAULT;
else
return 0;
}
DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
return -ENOENT;
}
#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 ipv4_tuple_to_nfattr(struct sk_buff *skb,
const struct nf_conntrack_tuple *tuple)
{
NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
&tuple->src.u3.ip);
NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
&tuple->dst.u3.ip);
return 0;
nfattr_failure:
return -1;
}
static const size_t cta_min_ip[CTA_IP_MAX] = {
[CTA_IP_V4_SRC-1] = sizeof(u_int32_t),
[CTA_IP_V4_DST-1] = sizeof(u_int32_t),
};
static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
struct nf_conntrack_tuple *t)
{
if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1])
return -EINVAL;
if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
return -EINVAL;
t->src.u3.ip =
*(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_SRC-1]);
t->dst.u3.ip =
*(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_DST-1]);
return 0;
}
#endif
static struct nf_sockopt_ops so_getorigdst = {
.pf = PF_INET,
.get_optmin = SO_ORIGINAL_DST,
.get_optmax = SO_ORIGINAL_DST+1,
.get = &getorigdst,
};
struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
.l3proto = PF_INET,
.name = "ipv4",
.pkt_to_tuple = ipv4_pkt_to_tuple,
.invert_tuple = ipv4_invert_tuple,
.print_tuple = ipv4_print_tuple,
.print_conntrack = ipv4_print_conntrack,
.prepare = ipv4_prepare,
.get_features = ipv4_get_features,
#if defined(CONFIG_NF_CT_NETLINK) || \
defined(CONFIG_NF_CT_NETLINK_MODULE)
.tuple_to_nfattr = ipv4_tuple_to_nfattr,
.nfattr_to_tuple = ipv4_nfattr_to_tuple,
#endif
.me = THIS_MODULE,
};
extern struct nf_conntrack_protocol nf_conntrack_protocol_tcp4;
extern struct nf_conntrack_protocol nf_conntrack_protocol_udp4;
extern struct nf_conntrack_protocol nf_conntrack_protocol_icmp;
static int init_or_cleanup(int init)
{
int ret = 0;
if (!init) goto cleanup;
ret = nf_register_sockopt(&so_getorigdst);
if (ret < 0) {
printk(KERN_ERR "Unable to register netfilter socket option\n");
goto cleanup_nothing;
}
ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_tcp4);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register tcp.\n");
goto cleanup_sockopt;
}
ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_udp4);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register udp.\n");
goto cleanup_tcp;
}
ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_icmp);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register icmp.\n");
goto cleanup_udp;
}
ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register ipv4\n");
goto cleanup_icmp;
}
ret = nf_register_hook(&ipv4_conntrack_defrag_ops);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register pre-routing defrag hook.\n");
goto cleanup_ipv4;
}
ret = nf_register_hook(&ipv4_conntrack_defrag_local_out_ops);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register local_out defrag hook.\n");
goto cleanup_defragops;
}
ret = nf_register_hook(&ipv4_conntrack_in_ops);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register pre-routing hook.\n");
goto cleanup_defraglocalops;
}
ret = nf_register_hook(&ipv4_conntrack_local_out_ops);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register local out hook.\n");
goto cleanup_inops;
}
ret = nf_register_hook(&ipv4_conntrack_helper_in_ops);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register local helper hook.\n");
goto cleanup_inandlocalops;
}
ret = nf_register_hook(&ipv4_conntrack_helper_out_ops);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register postrouting helper hook.\n");
goto cleanup_helperinops;
}
ret = nf_register_hook(&ipv4_conntrack_out_ops);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register post-routing hook.\n");
goto cleanup_helperoutops;
}
ret = nf_register_hook(&ipv4_conntrack_local_in_ops);
if (ret < 0) {
printk("nf_conntrack_ipv4: can't register local in hook.\n");
goto cleanup_inoutandlocalops;
}
#ifdef CONFIG_SYSCTL
nf_ct_ipv4_sysctl_header = register_sysctl_table(nf_ct_net_table, 0);
if (nf_ct_ipv4_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_ipv4_sysctl_header);
cleanup_localinops:
#endif
nf_unregister_hook(&ipv4_conntrack_local_in_ops);
cleanup_inoutandlocalops:
nf_unregister_hook(&ipv4_conntrack_out_ops);
cleanup_helperoutops:
nf_unregister_hook(&ipv4_conntrack_helper_out_ops);
cleanup_helperinops:
nf_unregister_hook(&ipv4_conntrack_helper_in_ops);
cleanup_inandlocalops:
nf_unregister_hook(&ipv4_conntrack_local_out_ops);
cleanup_inops:
nf_unregister_hook(&ipv4_conntrack_in_ops);
cleanup_defraglocalops:
nf_unregister_hook(&ipv4_conntrack_defrag_local_out_ops);
cleanup_defragops:
nf_unregister_hook(&ipv4_conntrack_defrag_ops);
cleanup_ipv4:
nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
cleanup_icmp:
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmp);
cleanup_udp:
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp4);
cleanup_tcp:
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp4);
cleanup_sockopt:
nf_unregister_sockopt(&so_getorigdst);
cleanup_nothing:
return ret;
}
MODULE_LICENSE("GPL");
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);
EXPORT_SYMBOL(nf_ct_ipv4_gather_frags);
