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>
30 #define DEBUGP(format, args...)
33 static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
34 struct nf_conntrack_tuple *tuple)
36 __be32 _addrs[2], *ap;
37 ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
38 sizeof(u_int32_t) * 2, _addrs);
42 tuple->src.u3.ip = ap[0];
43 tuple->dst.u3.ip = ap[1];
48 static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
49 const struct nf_conntrack_tuple *orig)
51 tuple->src.u3.ip = orig->dst.u3.ip;
52 tuple->dst.u3.ip = orig->src.u3.ip;
57 static int ipv4_print_tuple(struct seq_file *s,
58 const struct nf_conntrack_tuple *tuple)
60 return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
61 NIPQUAD(tuple->src.u3.ip),
62 NIPQUAD(tuple->dst.u3.ip));
65 static int ipv4_print_conntrack(struct seq_file *s,
66 const struct nf_conn *conntrack)
71 /* Returns new sk_buff, or NULL */
72 static struct sk_buff *
73 nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
78 skb = ip_defrag(skb, user);
82 ip_send_check(ip_hdr(skb));
88 ipv4_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
92 if (ip_hdr(*pskb)->frag_off & htons(IP_OFFSET)) {
93 if (net_ratelimit()) {
94 printk(KERN_ERR "ipv4_prepare: Frag of proto %u (hook=%u)\n",
95 ip_hdr(*pskb)->protocol, hooknum);
100 *dataoff = skb_network_offset(*pskb) + ip_hdrlen(*pskb);
101 *protonum = ip_hdr(*pskb)->protocol;
106 int nf_nat_module_is_loaded = 0;
107 EXPORT_SYMBOL_GPL(nf_nat_module_is_loaded);
109 static u_int32_t ipv4_get_features(const struct nf_conntrack_tuple *tuple)
111 if (nf_nat_module_is_loaded)
114 return NF_CT_F_BASIC;
117 static unsigned int ipv4_confirm(unsigned int hooknum,
118 struct sk_buff **pskb,
119 const struct net_device *in,
120 const struct net_device *out,
121 int (*okfn)(struct sk_buff *))
123 /* We've seen it coming out the other side: confirm it */
124 return nf_conntrack_confirm(pskb);
127 static unsigned int ipv4_conntrack_help(unsigned int hooknum,
128 struct sk_buff **pskb,
129 const struct net_device *in,
130 const struct net_device *out,
131 int (*okfn)(struct sk_buff *))
134 enum ip_conntrack_info ctinfo;
135 struct nf_conn_help *help;
137 /* This is where we call the helper: as the packet goes out. */
138 ct = nf_ct_get(*pskb, &ctinfo);
139 if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
142 help = nfct_help(ct);
143 if (!help || !help->helper)
146 return help->helper->help(pskb,
147 skb_network_offset(*pskb) + ip_hdrlen(*pskb),
151 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
152 struct sk_buff **pskb,
153 const struct net_device *in,
154 const struct net_device *out,
155 int (*okfn)(struct sk_buff *))
157 #if !defined(CONFIG_IP_NF_NAT) && !defined(CONFIG_IP_NF_NAT_MODULE)
158 /* Previously seen (loopback)? Ignore. Do this before
164 /* Gather fragments. */
165 if (ip_hdr(*pskb)->frag_off & htons(IP_MF | IP_OFFSET)) {
166 *pskb = nf_ct_ipv4_gather_frags(*pskb,
167 hooknum == NF_IP_PRE_ROUTING ?
168 IP_DEFRAG_CONNTRACK_IN :
169 IP_DEFRAG_CONNTRACK_OUT);
176 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
177 struct sk_buff **pskb,
178 const struct net_device *in,
179 const struct net_device *out,
180 int (*okfn)(struct sk_buff *))
182 return nf_conntrack_in(PF_INET, hooknum, pskb);
185 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
186 struct sk_buff **pskb,
187 const struct net_device *in,
188 const struct net_device *out,
189 int (*okfn)(struct sk_buff *))
191 /* root is playing with raw sockets. */
192 if ((*pskb)->len < sizeof(struct iphdr)
193 || ip_hdrlen(*pskb) < sizeof(struct iphdr)) {
195 printk("ipt_hook: happy cracking.\n");
198 return nf_conntrack_in(PF_INET, hooknum, pskb);
201 /* Connection tracking may drop packets, but never alters them, so
202 make it the first hook. */
203 static struct nf_hook_ops ipv4_conntrack_ops[] = {
205 .hook = ipv4_conntrack_defrag,
206 .owner = THIS_MODULE,
208 .hooknum = NF_IP_PRE_ROUTING,
209 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
212 .hook = ipv4_conntrack_in,
213 .owner = THIS_MODULE,
215 .hooknum = NF_IP_PRE_ROUTING,
216 .priority = NF_IP_PRI_CONNTRACK,
219 .hook = ipv4_conntrack_defrag,
220 .owner = THIS_MODULE,
222 .hooknum = NF_IP_LOCAL_OUT,
223 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
226 .hook = ipv4_conntrack_local,
227 .owner = THIS_MODULE,
229 .hooknum = NF_IP_LOCAL_OUT,
230 .priority = NF_IP_PRI_CONNTRACK,
233 .hook = ipv4_conntrack_help,
234 .owner = THIS_MODULE,
236 .hooknum = NF_IP_POST_ROUTING,
237 .priority = NF_IP_PRI_CONNTRACK_HELPER,
240 .hook = ipv4_conntrack_help,
241 .owner = THIS_MODULE,
243 .hooknum = NF_IP_LOCAL_IN,
244 .priority = NF_IP_PRI_CONNTRACK_HELPER,
247 .hook = ipv4_confirm,
248 .owner = THIS_MODULE,
250 .hooknum = NF_IP_POST_ROUTING,
251 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
254 .hook = ipv4_confirm,
255 .owner = THIS_MODULE,
257 .hooknum = NF_IP_LOCAL_IN,
258 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
262 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
263 static int log_invalid_proto_min = 0;
264 static int log_invalid_proto_max = 255;
266 static ctl_table ip_ct_sysctl_table[] = {
268 .ctl_name = NET_IPV4_NF_CONNTRACK_MAX,
269 .procname = "ip_conntrack_max",
270 .data = &nf_conntrack_max,
271 .maxlen = sizeof(int),
273 .proc_handler = &proc_dointvec,
276 .ctl_name = NET_IPV4_NF_CONNTRACK_COUNT,
277 .procname = "ip_conntrack_count",
278 .data = &nf_conntrack_count,
279 .maxlen = sizeof(int),
281 .proc_handler = &proc_dointvec,
284 .ctl_name = NET_IPV4_NF_CONNTRACK_BUCKETS,
285 .procname = "ip_conntrack_buckets",
286 .data = &nf_conntrack_htable_size,
287 .maxlen = sizeof(unsigned int),
289 .proc_handler = &proc_dointvec,
292 .ctl_name = NET_IPV4_NF_CONNTRACK_CHECKSUM,
293 .procname = "ip_conntrack_checksum",
294 .data = &nf_conntrack_checksum,
295 .maxlen = sizeof(int),
297 .proc_handler = &proc_dointvec,
300 .ctl_name = NET_IPV4_NF_CONNTRACK_LOG_INVALID,
301 .procname = "ip_conntrack_log_invalid",
302 .data = &nf_ct_log_invalid,
303 .maxlen = sizeof(unsigned int),
305 .proc_handler = &proc_dointvec_minmax,
306 .strategy = &sysctl_intvec,
307 .extra1 = &log_invalid_proto_min,
308 .extra2 = &log_invalid_proto_max,
314 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
316 /* Fast function for those who don't want to parse /proc (and I don't
318 /* Reversing the socket's dst/src point of view gives us the reply
321 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
323 struct inet_sock *inet = inet_sk(sk);
324 struct nf_conntrack_tuple_hash *h;
325 struct nf_conntrack_tuple tuple;
327 NF_CT_TUPLE_U_BLANK(&tuple);
328 tuple.src.u3.ip = inet->rcv_saddr;
329 tuple.src.u.tcp.port = inet->sport;
330 tuple.dst.u3.ip = inet->daddr;
331 tuple.dst.u.tcp.port = inet->dport;
332 tuple.src.l3num = PF_INET;
333 tuple.dst.protonum = IPPROTO_TCP;
335 /* We only do TCP at the moment: is there a better way? */
336 if (strcmp(sk->sk_prot->name, "TCP")) {
337 DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
341 if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
342 DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
343 *len, sizeof(struct sockaddr_in));
347 h = nf_conntrack_find_get(&tuple, NULL);
349 struct sockaddr_in sin;
350 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
352 sin.sin_family = AF_INET;
353 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
354 .tuple.dst.u.tcp.port;
355 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
357 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
359 DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
360 NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
362 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
367 DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
368 NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
369 NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
373 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
375 #include <linux/netfilter/nfnetlink.h>
376 #include <linux/netfilter/nfnetlink_conntrack.h>
378 static int ipv4_tuple_to_nfattr(struct sk_buff *skb,
379 const struct nf_conntrack_tuple *tuple)
381 NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
383 NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
391 static const size_t cta_min_ip[CTA_IP_MAX] = {
392 [CTA_IP_V4_SRC-1] = sizeof(u_int32_t),
393 [CTA_IP_V4_DST-1] = sizeof(u_int32_t),
396 static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
397 struct nf_conntrack_tuple *t)
399 if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1])
402 if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
405 t->src.u3.ip = *(__be32 *)NFA_DATA(tb[CTA_IP_V4_SRC-1]);
406 t->dst.u3.ip = *(__be32 *)NFA_DATA(tb[CTA_IP_V4_DST-1]);
412 static struct nf_sockopt_ops so_getorigdst = {
414 .get_optmin = SO_ORIGINAL_DST,
415 .get_optmax = SO_ORIGINAL_DST+1,
419 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
422 .pkt_to_tuple = ipv4_pkt_to_tuple,
423 .invert_tuple = ipv4_invert_tuple,
424 .print_tuple = ipv4_print_tuple,
425 .print_conntrack = ipv4_print_conntrack,
426 .prepare = ipv4_prepare,
427 .get_features = ipv4_get_features,
428 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
429 .tuple_to_nfattr = ipv4_tuple_to_nfattr,
430 .nfattr_to_tuple = ipv4_nfattr_to_tuple,
432 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
433 .ctl_table_path = nf_net_ipv4_netfilter_sysctl_path,
434 .ctl_table = ip_ct_sysctl_table,
439 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
440 MODULE_ALIAS("ip_conntrack");
441 MODULE_LICENSE("GPL");
443 static int __init nf_conntrack_l3proto_ipv4_init(void)
449 ret = nf_register_sockopt(&so_getorigdst);
451 printk(KERN_ERR "Unable to register netfilter socket option\n");
455 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
457 printk("nf_conntrack_ipv4: can't register tcp.\n");
458 goto cleanup_sockopt;
461 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
463 printk("nf_conntrack_ipv4: can't register udp.\n");
467 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
469 printk("nf_conntrack_ipv4: can't register icmp.\n");
473 ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
475 printk("nf_conntrack_ipv4: can't register ipv4\n");
479 ret = nf_register_hooks(ipv4_conntrack_ops,
480 ARRAY_SIZE(ipv4_conntrack_ops));
482 printk("nf_conntrack_ipv4: can't register hooks.\n");
485 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
486 ret = nf_conntrack_ipv4_compat_init();
491 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
493 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
496 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
498 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
500 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
502 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
504 nf_unregister_sockopt(&so_getorigdst);
508 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
511 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
512 nf_conntrack_ipv4_compat_fini();
514 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
515 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
516 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
517 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
518 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
519 nf_unregister_sockopt(&so_getorigdst);
522 module_init(nf_conntrack_l3proto_ipv4_init);
523 module_exit(nf_conntrack_l3proto_ipv4_fini);