![Jörn Engel](/assets/img/avatar_default.png)
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
526 lines
14 KiB
C
526 lines
14 KiB
C
/* (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/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 || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
|
|
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_ops[] = {
|
|
{
|
|
.hook = ipv4_conntrack_defrag,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET,
|
|
.hooknum = NF_IP_PRE_ROUTING,
|
|
.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
|
|
},
|
|
{
|
|
.hook = ipv4_conntrack_in,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET,
|
|
.hooknum = NF_IP_PRE_ROUTING,
|
|
.priority = NF_IP_PRI_CONNTRACK,
|
|
},
|
|
{
|
|
.hook = ipv4_conntrack_defrag,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET,
|
|
.hooknum = NF_IP_LOCAL_OUT,
|
|
.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
|
|
},
|
|
{
|
|
.hook = ipv4_conntrack_local,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET,
|
|
.hooknum = NF_IP_LOCAL_OUT,
|
|
.priority = NF_IP_PRI_CONNTRACK,
|
|
},
|
|
{
|
|
.hook = ipv4_conntrack_help,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET,
|
|
.hooknum = NF_IP_POST_ROUTING,
|
|
.priority = NF_IP_PRI_CONNTRACK_HELPER,
|
|
},
|
|
{
|
|
.hook = ipv4_conntrack_help,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET,
|
|
.hooknum = NF_IP_LOCAL_IN,
|
|
.priority = NF_IP_PRI_CONNTRACK_HELPER,
|
|
},
|
|
{
|
|
.hook = ipv4_confirm,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET,
|
|
.hooknum = NF_IP_POST_ROUTING,
|
|
.priority = NF_IP_PRI_CONNTRACK_CONFIRM,
|
|
},
|
|
{
|
|
.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;
|
|
memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
|
|
|
|
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;
|
|
|
|
MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
|
|
MODULE_LICENSE("GPL");
|
|
|
|
static int __init nf_conntrack_l3proto_ipv4_init(void)
|
|
{
|
|
int ret = 0;
|
|
|
|
need_conntrack();
|
|
|
|
ret = nf_register_sockopt(&so_getorigdst);
|
|
if (ret < 0) {
|
|
printk(KERN_ERR "Unable to register netfilter socket option\n");
|
|
return ret;
|
|
}
|
|
|
|
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_hooks(ipv4_conntrack_ops,
|
|
ARRAY_SIZE(ipv4_conntrack_ops));
|
|
if (ret < 0) {
|
|
printk("nf_conntrack_ipv4: can't register hooks.\n");
|
|
goto cleanup_ipv4;
|
|
}
|
|
#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_hooks;
|
|
}
|
|
#endif
|
|
return ret;
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
cleanup_hooks:
|
|
nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
|
|
#endif
|
|
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);
|
|
return ret;
|
|
}
|
|
|
|
static void __exit nf_conntrack_l3proto_ipv4_fini(void)
|
|
{
|
|
synchronize_net();
|
|
#ifdef CONFIG_SYSCTL
|
|
unregister_sysctl_table(nf_ct_ipv4_sysctl_header);
|
|
#endif
|
|
nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
|
|
nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
|
|
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmp);
|
|
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp4);
|
|
nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp4);
|
|
nf_unregister_sockopt(&so_getorigdst);
|
|
}
|
|
|
|
module_init(nf_conntrack_l3proto_ipv4_init);
|
|
module_exit(nf_conntrack_l3proto_ipv4_fini);
|
|
|
|
EXPORT_SYMBOL(nf_ct_ipv4_gather_frags);
|