1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
9 #include <linux/types.h>
11 #include <linux/netfilter.h>
12 #include <linux/module.h>
13 #include <linux/skbuff.h>
14 #include <linux/icmp.h>
15 #include <linux/sysctl.h>
16 #include <net/route.h>
19 #include <linux/netfilter_ipv4.h>
20 #include <net/netfilter/nf_conntrack.h>
21 #include <net/netfilter/nf_conntrack_helper.h>
22 #include <net/netfilter/nf_conntrack_l4proto.h>
23 #include <net/netfilter/nf_conntrack_l3proto.h>
24 #include <net/netfilter/nf_conntrack_core.h>
25 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
27 static int ipv4_pkt_to_tuple(const struct sk_buff
*skb
, unsigned int nhoff
,
28 struct nf_conntrack_tuple
*tuple
)
30 __be32 _addrs
[2], *ap
;
31 ap
= skb_header_pointer(skb
, nhoff
+ offsetof(struct iphdr
, saddr
),
32 sizeof(u_int32_t
) * 2, _addrs
);
36 tuple
->src
.u3
.ip
= ap
[0];
37 tuple
->dst
.u3
.ip
= ap
[1];
42 static int ipv4_invert_tuple(struct nf_conntrack_tuple
*tuple
,
43 const struct nf_conntrack_tuple
*orig
)
45 tuple
->src
.u3
.ip
= orig
->dst
.u3
.ip
;
46 tuple
->dst
.u3
.ip
= orig
->src
.u3
.ip
;
51 static int ipv4_print_tuple(struct seq_file
*s
,
52 const struct nf_conntrack_tuple
*tuple
)
54 return seq_printf(s
, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
55 NIPQUAD(tuple
->src
.u3
.ip
),
56 NIPQUAD(tuple
->dst
.u3
.ip
));
59 static int ipv4_print_conntrack(struct seq_file
*s
,
60 const struct nf_conn
*conntrack
)
65 /* Returns new sk_buff, or NULL */
66 static int nf_ct_ipv4_gather_frags(struct sk_buff
*skb
, u_int32_t user
)
73 err
= ip_defrag(skb
, user
);
77 ip_send_check(ip_hdr(skb
));
82 static int ipv4_get_l4proto(const struct sk_buff
*skb
, unsigned int nhoff
,
83 unsigned int *dataoff
, u_int8_t
*protonum
)
85 struct iphdr _iph
, *iph
;
87 iph
= skb_header_pointer(skb
, nhoff
, sizeof(_iph
), &_iph
);
91 /* Conntrack defragments packets, we might still see fragments
92 * inside ICMP packets though. */
93 if (iph
->frag_off
& htons(IP_OFFSET
))
96 *dataoff
= nhoff
+ (iph
->ihl
<< 2);
97 *protonum
= iph
->protocol
;
102 static unsigned int ipv4_confirm(unsigned int hooknum
,
104 const struct net_device
*in
,
105 const struct net_device
*out
,
106 int (*okfn
)(struct sk_buff
*))
108 /* We've seen it coming out the other side: confirm it */
109 return nf_conntrack_confirm(skb
);
112 static unsigned int ipv4_conntrack_help(unsigned int hooknum
,
114 const struct net_device
*in
,
115 const struct net_device
*out
,
116 int (*okfn
)(struct sk_buff
*))
119 enum ip_conntrack_info ctinfo
;
120 struct nf_conn_help
*help
;
121 struct nf_conntrack_helper
*helper
;
123 /* This is where we call the helper: as the packet goes out. */
124 ct
= nf_ct_get(skb
, &ctinfo
);
125 if (!ct
|| ctinfo
== IP_CT_RELATED
+ IP_CT_IS_REPLY
)
128 help
= nfct_help(ct
);
131 /* rcu_read_lock()ed by nf_hook_slow */
132 helper
= rcu_dereference(help
->helper
);
135 return helper
->help(skb
, skb_network_offset(skb
) + ip_hdrlen(skb
),
139 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum
,
141 const struct net_device
*in
,
142 const struct net_device
*out
,
143 int (*okfn
)(struct sk_buff
*))
145 /* Previously seen (loopback)? Ignore. Do this before
150 /* Gather fragments. */
151 if (ip_hdr(skb
)->frag_off
& htons(IP_MF
| IP_OFFSET
)) {
152 if (nf_ct_ipv4_gather_frags(skb
,
153 hooknum
== NF_INET_PRE_ROUTING
?
154 IP_DEFRAG_CONNTRACK_IN
:
155 IP_DEFRAG_CONNTRACK_OUT
))
161 static unsigned int ipv4_conntrack_in(unsigned int hooknum
,
163 const struct net_device
*in
,
164 const struct net_device
*out
,
165 int (*okfn
)(struct sk_buff
*))
167 return nf_conntrack_in(PF_INET
, hooknum
, skb
);
170 static unsigned int ipv4_conntrack_local(unsigned int hooknum
,
172 const struct net_device
*in
,
173 const struct net_device
*out
,
174 int (*okfn
)(struct sk_buff
*))
176 /* root is playing with raw sockets. */
177 if (skb
->len
< sizeof(struct iphdr
) ||
178 ip_hdrlen(skb
) < sizeof(struct iphdr
)) {
180 printk("ipt_hook: happy cracking.\n");
183 return nf_conntrack_in(PF_INET
, hooknum
, skb
);
186 /* Connection tracking may drop packets, but never alters them, so
187 make it the first hook. */
188 static struct nf_hook_ops ipv4_conntrack_ops
[] = {
190 .hook
= ipv4_conntrack_defrag
,
191 .owner
= THIS_MODULE
,
193 .hooknum
= NF_INET_PRE_ROUTING
,
194 .priority
= NF_IP_PRI_CONNTRACK_DEFRAG
,
197 .hook
= ipv4_conntrack_in
,
198 .owner
= THIS_MODULE
,
200 .hooknum
= NF_INET_PRE_ROUTING
,
201 .priority
= NF_IP_PRI_CONNTRACK
,
204 .hook
= ipv4_conntrack_defrag
,
205 .owner
= THIS_MODULE
,
207 .hooknum
= NF_INET_LOCAL_OUT
,
208 .priority
= NF_IP_PRI_CONNTRACK_DEFRAG
,
211 .hook
= ipv4_conntrack_local
,
212 .owner
= THIS_MODULE
,
214 .hooknum
= NF_INET_LOCAL_OUT
,
215 .priority
= NF_IP_PRI_CONNTRACK
,
218 .hook
= ipv4_conntrack_help
,
219 .owner
= THIS_MODULE
,
221 .hooknum
= NF_INET_POST_ROUTING
,
222 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
225 .hook
= ipv4_conntrack_help
,
226 .owner
= THIS_MODULE
,
228 .hooknum
= NF_INET_LOCAL_IN
,
229 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
232 .hook
= ipv4_confirm
,
233 .owner
= THIS_MODULE
,
235 .hooknum
= NF_INET_POST_ROUTING
,
236 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
239 .hook
= ipv4_confirm
,
240 .owner
= THIS_MODULE
,
242 .hooknum
= NF_INET_LOCAL_IN
,
243 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
247 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
248 static int log_invalid_proto_min
= 0;
249 static int log_invalid_proto_max
= 255;
251 static ctl_table ip_ct_sysctl_table
[] = {
253 .ctl_name
= NET_IPV4_NF_CONNTRACK_MAX
,
254 .procname
= "ip_conntrack_max",
255 .data
= &nf_conntrack_max
,
256 .maxlen
= sizeof(int),
258 .proc_handler
= &proc_dointvec
,
261 .ctl_name
= NET_IPV4_NF_CONNTRACK_COUNT
,
262 .procname
= "ip_conntrack_count",
263 .data
= &nf_conntrack_count
,
264 .maxlen
= sizeof(int),
266 .proc_handler
= &proc_dointvec
,
269 .ctl_name
= NET_IPV4_NF_CONNTRACK_BUCKETS
,
270 .procname
= "ip_conntrack_buckets",
271 .data
= &nf_conntrack_htable_size
,
272 .maxlen
= sizeof(unsigned int),
274 .proc_handler
= &proc_dointvec
,
277 .ctl_name
= NET_IPV4_NF_CONNTRACK_CHECKSUM
,
278 .procname
= "ip_conntrack_checksum",
279 .data
= &nf_conntrack_checksum
,
280 .maxlen
= sizeof(int),
282 .proc_handler
= &proc_dointvec
,
285 .ctl_name
= NET_IPV4_NF_CONNTRACK_LOG_INVALID
,
286 .procname
= "ip_conntrack_log_invalid",
287 .data
= &nf_ct_log_invalid
,
288 .maxlen
= sizeof(unsigned int),
290 .proc_handler
= &proc_dointvec_minmax
,
291 .strategy
= &sysctl_intvec
,
292 .extra1
= &log_invalid_proto_min
,
293 .extra2
= &log_invalid_proto_max
,
299 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
301 /* Fast function for those who don't want to parse /proc (and I don't
303 /* Reversing the socket's dst/src point of view gives us the reply
306 getorigdst(struct sock
*sk
, int optval
, void __user
*user
, int *len
)
308 struct inet_sock
*inet
= inet_sk(sk
);
309 struct nf_conntrack_tuple_hash
*h
;
310 struct nf_conntrack_tuple tuple
;
312 NF_CT_TUPLE_U_BLANK(&tuple
);
313 tuple
.src
.u3
.ip
= inet
->rcv_saddr
;
314 tuple
.src
.u
.tcp
.port
= inet
->sport
;
315 tuple
.dst
.u3
.ip
= inet
->daddr
;
316 tuple
.dst
.u
.tcp
.port
= inet
->dport
;
317 tuple
.src
.l3num
= PF_INET
;
318 tuple
.dst
.protonum
= IPPROTO_TCP
;
320 /* We only do TCP at the moment: is there a better way? */
321 if (strcmp(sk
->sk_prot
->name
, "TCP")) {
322 pr_debug("SO_ORIGINAL_DST: Not a TCP socket\n");
326 if ((unsigned int) *len
< sizeof(struct sockaddr_in
)) {
327 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
328 *len
, sizeof(struct sockaddr_in
));
332 h
= nf_conntrack_find_get(&tuple
);
334 struct sockaddr_in sin
;
335 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
337 sin
.sin_family
= AF_INET
;
338 sin
.sin_port
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
339 .tuple
.dst
.u
.tcp
.port
;
340 sin
.sin_addr
.s_addr
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
342 memset(sin
.sin_zero
, 0, sizeof(sin
.sin_zero
));
344 pr_debug("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
345 NIPQUAD(sin
.sin_addr
.s_addr
), ntohs(sin
.sin_port
));
347 if (copy_to_user(user
, &sin
, sizeof(sin
)) != 0)
352 pr_debug("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
353 NIPQUAD(tuple
.src
.u3
.ip
), ntohs(tuple
.src
.u
.tcp
.port
),
354 NIPQUAD(tuple
.dst
.u3
.ip
), ntohs(tuple
.dst
.u
.tcp
.port
));
358 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
360 #include <linux/netfilter/nfnetlink.h>
361 #include <linux/netfilter/nfnetlink_conntrack.h>
363 static int ipv4_tuple_to_nlattr(struct sk_buff
*skb
,
364 const struct nf_conntrack_tuple
*tuple
)
366 NLA_PUT(skb
, CTA_IP_V4_SRC
, sizeof(u_int32_t
),
368 NLA_PUT(skb
, CTA_IP_V4_DST
, sizeof(u_int32_t
),
376 static const struct nla_policy ipv4_nla_policy
[CTA_IP_MAX
+1] = {
377 [CTA_IP_V4_SRC
] = { .type
= NLA_U32
},
378 [CTA_IP_V4_DST
] = { .type
= NLA_U32
},
381 static int ipv4_nlattr_to_tuple(struct nlattr
*tb
[],
382 struct nf_conntrack_tuple
*t
)
384 if (!tb
[CTA_IP_V4_SRC
] || !tb
[CTA_IP_V4_DST
])
387 t
->src
.u3
.ip
= *(__be32
*)nla_data(tb
[CTA_IP_V4_SRC
]);
388 t
->dst
.u3
.ip
= *(__be32
*)nla_data(tb
[CTA_IP_V4_DST
]);
394 static struct nf_sockopt_ops so_getorigdst
= {
396 .get_optmin
= SO_ORIGINAL_DST
,
397 .get_optmax
= SO_ORIGINAL_DST
+1,
399 .owner
= THIS_MODULE
,
402 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly
= {
405 .pkt_to_tuple
= ipv4_pkt_to_tuple
,
406 .invert_tuple
= ipv4_invert_tuple
,
407 .print_tuple
= ipv4_print_tuple
,
408 .print_conntrack
= ipv4_print_conntrack
,
409 .get_l4proto
= ipv4_get_l4proto
,
410 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
411 .tuple_to_nlattr
= ipv4_tuple_to_nlattr
,
412 .nlattr_to_tuple
= ipv4_nlattr_to_tuple
,
413 .nla_policy
= ipv4_nla_policy
,
415 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
416 .ctl_table_path
= nf_net_ipv4_netfilter_sysctl_path
,
417 .ctl_table
= ip_ct_sysctl_table
,
422 module_param_call(hashsize
, nf_conntrack_set_hashsize
, param_get_uint
,
423 &nf_conntrack_htable_size
, 0600);
425 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET
));
426 MODULE_ALIAS("ip_conntrack");
427 MODULE_LICENSE("GPL");
429 static int __init
nf_conntrack_l3proto_ipv4_init(void)
435 ret
= nf_register_sockopt(&so_getorigdst
);
437 printk(KERN_ERR
"Unable to register netfilter socket option\n");
441 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4
);
443 printk("nf_conntrack_ipv4: can't register tcp.\n");
444 goto cleanup_sockopt
;
447 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4
);
449 printk("nf_conntrack_ipv4: can't register udp.\n");
453 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp
);
455 printk("nf_conntrack_ipv4: can't register icmp.\n");
459 ret
= nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4
);
461 printk("nf_conntrack_ipv4: can't register ipv4\n");
465 ret
= nf_register_hooks(ipv4_conntrack_ops
,
466 ARRAY_SIZE(ipv4_conntrack_ops
));
468 printk("nf_conntrack_ipv4: can't register hooks.\n");
471 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
472 ret
= nf_conntrack_ipv4_compat_init();
477 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
479 nf_unregister_hooks(ipv4_conntrack_ops
, ARRAY_SIZE(ipv4_conntrack_ops
));
482 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
484 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp
);
486 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4
);
488 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4
);
490 nf_unregister_sockopt(&so_getorigdst
);
494 static void __exit
nf_conntrack_l3proto_ipv4_fini(void)
497 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
498 nf_conntrack_ipv4_compat_fini();
500 nf_unregister_hooks(ipv4_conntrack_ops
, ARRAY_SIZE(ipv4_conntrack_ops
));
501 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
502 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp
);
503 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4
);
504 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4
);
505 nf_unregister_sockopt(&so_getorigdst
);
508 module_init(nf_conntrack_l3proto_ipv4_init
);
509 module_exit(nf_conntrack_l3proto_ipv4_fini
);
511 void need_ipv4_conntrack(void)
515 EXPORT_SYMBOL_GPL(need_ipv4_conntrack
);