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 struct sk_buff
*
67 nf_ct_ipv4_gather_frags(struct sk_buff
*skb
, u_int32_t user
)
72 skb
= ip_defrag(skb
, user
);
76 ip_send_check(ip_hdr(skb
));
81 static int ipv4_get_l4proto(const struct sk_buff
*skb
, unsigned int nhoff
,
82 unsigned int *dataoff
, u_int8_t
*protonum
)
84 struct iphdr _iph
, *iph
;
86 iph
= skb_header_pointer(skb
, nhoff
, sizeof(_iph
), &_iph
);
91 if (iph
->frag_off
& htons(IP_OFFSET
)) {
92 if (net_ratelimit()) {
93 printk(KERN_ERR
"ipv4_get_l4proto: Frag of proto %u\n",
99 *dataoff
= nhoff
+ (iph
->ihl
<< 2);
100 *protonum
= iph
->protocol
;
105 static unsigned int ipv4_confirm(unsigned int hooknum
,
106 struct sk_buff
**pskb
,
107 const struct net_device
*in
,
108 const struct net_device
*out
,
109 int (*okfn
)(struct sk_buff
*))
111 /* We've seen it coming out the other side: confirm it */
112 return nf_conntrack_confirm(pskb
);
115 static unsigned int ipv4_conntrack_help(unsigned int hooknum
,
116 struct sk_buff
**pskb
,
117 const struct net_device
*in
,
118 const struct net_device
*out
,
119 int (*okfn
)(struct sk_buff
*))
122 enum ip_conntrack_info ctinfo
;
123 struct nf_conn_help
*help
;
124 struct nf_conntrack_helper
*helper
;
126 /* This is where we call the helper: as the packet goes out. */
127 ct
= nf_ct_get(*pskb
, &ctinfo
);
128 if (!ct
|| ctinfo
== IP_CT_RELATED
+ IP_CT_IS_REPLY
)
131 help
= nfct_help(ct
);
134 /* rcu_read_lock()ed by nf_hook_slow */
135 helper
= rcu_dereference(help
->helper
);
138 return helper
->help(pskb
, skb_network_offset(*pskb
) + ip_hdrlen(*pskb
),
142 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum
,
143 struct sk_buff
**pskb
,
144 const struct net_device
*in
,
145 const struct net_device
*out
,
146 int (*okfn
)(struct sk_buff
*))
148 /* Previously seen (loopback)? Ignore. Do this before
153 /* Gather fragments. */
154 if (ip_hdr(*pskb
)->frag_off
& htons(IP_MF
| IP_OFFSET
)) {
155 *pskb
= nf_ct_ipv4_gather_frags(*pskb
,
156 hooknum
== NF_IP_PRE_ROUTING
?
157 IP_DEFRAG_CONNTRACK_IN
:
158 IP_DEFRAG_CONNTRACK_OUT
);
165 static unsigned int ipv4_conntrack_in(unsigned int hooknum
,
166 struct sk_buff
**pskb
,
167 const struct net_device
*in
,
168 const struct net_device
*out
,
169 int (*okfn
)(struct sk_buff
*))
171 return nf_conntrack_in(PF_INET
, hooknum
, pskb
);
174 static unsigned int ipv4_conntrack_local(unsigned int hooknum
,
175 struct sk_buff
**pskb
,
176 const struct net_device
*in
,
177 const struct net_device
*out
,
178 int (*okfn
)(struct sk_buff
*))
180 /* root is playing with raw sockets. */
181 if ((*pskb
)->len
< sizeof(struct iphdr
)
182 || ip_hdrlen(*pskb
) < sizeof(struct iphdr
)) {
184 printk("ipt_hook: happy cracking.\n");
187 return nf_conntrack_in(PF_INET
, hooknum
, pskb
);
190 /* Connection tracking may drop packets, but never alters them, so
191 make it the first hook. */
192 static struct nf_hook_ops ipv4_conntrack_ops
[] = {
194 .hook
= ipv4_conntrack_defrag
,
195 .owner
= THIS_MODULE
,
197 .hooknum
= NF_IP_PRE_ROUTING
,
198 .priority
= NF_IP_PRI_CONNTRACK_DEFRAG
,
201 .hook
= ipv4_conntrack_in
,
202 .owner
= THIS_MODULE
,
204 .hooknum
= NF_IP_PRE_ROUTING
,
205 .priority
= NF_IP_PRI_CONNTRACK
,
208 .hook
= ipv4_conntrack_defrag
,
209 .owner
= THIS_MODULE
,
211 .hooknum
= NF_IP_LOCAL_OUT
,
212 .priority
= NF_IP_PRI_CONNTRACK_DEFRAG
,
215 .hook
= ipv4_conntrack_local
,
216 .owner
= THIS_MODULE
,
218 .hooknum
= NF_IP_LOCAL_OUT
,
219 .priority
= NF_IP_PRI_CONNTRACK
,
222 .hook
= ipv4_conntrack_help
,
223 .owner
= THIS_MODULE
,
225 .hooknum
= NF_IP_POST_ROUTING
,
226 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
229 .hook
= ipv4_conntrack_help
,
230 .owner
= THIS_MODULE
,
232 .hooknum
= NF_IP_LOCAL_IN
,
233 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
236 .hook
= ipv4_confirm
,
237 .owner
= THIS_MODULE
,
239 .hooknum
= NF_IP_POST_ROUTING
,
240 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
243 .hook
= ipv4_confirm
,
244 .owner
= THIS_MODULE
,
246 .hooknum
= NF_IP_LOCAL_IN
,
247 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
251 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
252 static int log_invalid_proto_min
= 0;
253 static int log_invalid_proto_max
= 255;
255 static ctl_table ip_ct_sysctl_table
[] = {
257 .ctl_name
= NET_IPV4_NF_CONNTRACK_MAX
,
258 .procname
= "ip_conntrack_max",
259 .data
= &nf_conntrack_max
,
260 .maxlen
= sizeof(int),
262 .proc_handler
= &proc_dointvec
,
265 .ctl_name
= NET_IPV4_NF_CONNTRACK_COUNT
,
266 .procname
= "ip_conntrack_count",
267 .data
= &nf_conntrack_count
,
268 .maxlen
= sizeof(int),
270 .proc_handler
= &proc_dointvec
,
273 .ctl_name
= NET_IPV4_NF_CONNTRACK_BUCKETS
,
274 .procname
= "ip_conntrack_buckets",
275 .data
= &nf_conntrack_htable_size
,
276 .maxlen
= sizeof(unsigned int),
278 .proc_handler
= &proc_dointvec
,
281 .ctl_name
= NET_IPV4_NF_CONNTRACK_CHECKSUM
,
282 .procname
= "ip_conntrack_checksum",
283 .data
= &nf_conntrack_checksum
,
284 .maxlen
= sizeof(int),
286 .proc_handler
= &proc_dointvec
,
289 .ctl_name
= NET_IPV4_NF_CONNTRACK_LOG_INVALID
,
290 .procname
= "ip_conntrack_log_invalid",
291 .data
= &nf_ct_log_invalid
,
292 .maxlen
= sizeof(unsigned int),
294 .proc_handler
= &proc_dointvec_minmax
,
295 .strategy
= &sysctl_intvec
,
296 .extra1
= &log_invalid_proto_min
,
297 .extra2
= &log_invalid_proto_max
,
303 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
305 /* Fast function for those who don't want to parse /proc (and I don't
307 /* Reversing the socket's dst/src point of view gives us the reply
310 getorigdst(struct sock
*sk
, int optval
, void __user
*user
, int *len
)
312 struct inet_sock
*inet
= inet_sk(sk
);
313 struct nf_conntrack_tuple_hash
*h
;
314 struct nf_conntrack_tuple tuple
;
316 NF_CT_TUPLE_U_BLANK(&tuple
);
317 tuple
.src
.u3
.ip
= inet
->rcv_saddr
;
318 tuple
.src
.u
.tcp
.port
= inet
->sport
;
319 tuple
.dst
.u3
.ip
= inet
->daddr
;
320 tuple
.dst
.u
.tcp
.port
= inet
->dport
;
321 tuple
.src
.l3num
= PF_INET
;
322 tuple
.dst
.protonum
= IPPROTO_TCP
;
324 /* We only do TCP at the moment: is there a better way? */
325 if (strcmp(sk
->sk_prot
->name
, "TCP")) {
326 pr_debug("SO_ORIGINAL_DST: Not a TCP socket\n");
330 if ((unsigned int) *len
< sizeof(struct sockaddr_in
)) {
331 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
332 *len
, sizeof(struct sockaddr_in
));
336 h
= nf_conntrack_find_get(&tuple
);
338 struct sockaddr_in sin
;
339 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
341 sin
.sin_family
= AF_INET
;
342 sin
.sin_port
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
343 .tuple
.dst
.u
.tcp
.port
;
344 sin
.sin_addr
.s_addr
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
346 memset(sin
.sin_zero
, 0, sizeof(sin
.sin_zero
));
348 pr_debug("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
349 NIPQUAD(sin
.sin_addr
.s_addr
), ntohs(sin
.sin_port
));
351 if (copy_to_user(user
, &sin
, sizeof(sin
)) != 0)
356 pr_debug("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
357 NIPQUAD(tuple
.src
.u3
.ip
), ntohs(tuple
.src
.u
.tcp
.port
),
358 NIPQUAD(tuple
.dst
.u3
.ip
), ntohs(tuple
.dst
.u
.tcp
.port
));
362 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
364 #include <linux/netfilter/nfnetlink.h>
365 #include <linux/netfilter/nfnetlink_conntrack.h>
367 static int ipv4_tuple_to_nfattr(struct sk_buff
*skb
,
368 const struct nf_conntrack_tuple
*tuple
)
370 NFA_PUT(skb
, CTA_IP_V4_SRC
, sizeof(u_int32_t
),
372 NFA_PUT(skb
, CTA_IP_V4_DST
, sizeof(u_int32_t
),
380 static const size_t cta_min_ip
[CTA_IP_MAX
] = {
381 [CTA_IP_V4_SRC
-1] = sizeof(u_int32_t
),
382 [CTA_IP_V4_DST
-1] = sizeof(u_int32_t
),
385 static int ipv4_nfattr_to_tuple(struct nfattr
*tb
[],
386 struct nf_conntrack_tuple
*t
)
388 if (!tb
[CTA_IP_V4_SRC
-1] || !tb
[CTA_IP_V4_DST
-1])
391 if (nfattr_bad_size(tb
, CTA_IP_MAX
, cta_min_ip
))
394 t
->src
.u3
.ip
= *(__be32
*)NFA_DATA(tb
[CTA_IP_V4_SRC
-1]);
395 t
->dst
.u3
.ip
= *(__be32
*)NFA_DATA(tb
[CTA_IP_V4_DST
-1]);
401 static struct nf_sockopt_ops so_getorigdst
= {
403 .get_optmin
= SO_ORIGINAL_DST
,
404 .get_optmax
= SO_ORIGINAL_DST
+1,
408 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4
= {
411 .pkt_to_tuple
= ipv4_pkt_to_tuple
,
412 .invert_tuple
= ipv4_invert_tuple
,
413 .print_tuple
= ipv4_print_tuple
,
414 .print_conntrack
= ipv4_print_conntrack
,
415 .get_l4proto
= ipv4_get_l4proto
,
416 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
417 .tuple_to_nfattr
= ipv4_tuple_to_nfattr
,
418 .nfattr_to_tuple
= ipv4_nfattr_to_tuple
,
420 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
421 .ctl_table_path
= nf_net_ipv4_netfilter_sysctl_path
,
422 .ctl_table
= ip_ct_sysctl_table
,
427 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET
));
428 MODULE_ALIAS("ip_conntrack");
429 MODULE_LICENSE("GPL");
431 static int __init
nf_conntrack_l3proto_ipv4_init(void)
437 ret
= nf_register_sockopt(&so_getorigdst
);
439 printk(KERN_ERR
"Unable to register netfilter socket option\n");
443 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4
);
445 printk("nf_conntrack_ipv4: can't register tcp.\n");
446 goto cleanup_sockopt
;
449 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4
);
451 printk("nf_conntrack_ipv4: can't register udp.\n");
455 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp
);
457 printk("nf_conntrack_ipv4: can't register icmp.\n");
461 ret
= nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4
);
463 printk("nf_conntrack_ipv4: can't register ipv4\n");
467 ret
= nf_register_hooks(ipv4_conntrack_ops
,
468 ARRAY_SIZE(ipv4_conntrack_ops
));
470 printk("nf_conntrack_ipv4: can't register hooks.\n");
473 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
474 ret
= nf_conntrack_ipv4_compat_init();
479 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
481 nf_unregister_hooks(ipv4_conntrack_ops
, ARRAY_SIZE(ipv4_conntrack_ops
));
484 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
486 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp
);
488 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4
);
490 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4
);
492 nf_unregister_sockopt(&so_getorigdst
);
496 static void __exit
nf_conntrack_l3proto_ipv4_fini(void)
499 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
500 nf_conntrack_ipv4_compat_fini();
502 nf_unregister_hooks(ipv4_conntrack_ops
, ARRAY_SIZE(ipv4_conntrack_ops
));
503 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
504 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp
);
505 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4
);
506 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4
);
507 nf_unregister_sockopt(&so_getorigdst
);
510 module_init(nf_conntrack_l3proto_ipv4_init
);
511 module_exit(nf_conntrack_l3proto_ipv4_fini
);