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;
136 struct nf_conntrack_helper *helper;
138 /* This is where we call the helper: as the packet goes out. */
139 ct = nf_ct_get(*pskb, &ctinfo);
140 if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
143 help = nfct_help(ct);
146 /* rcu_read_lock()ed by nf_hook_slow */
147 helper = rcu_dereference(help->helper);
150 return helper->help(pskb, skb_network_offset(*pskb) + ip_hdrlen(*pskb),
154 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
155 struct sk_buff **pskb,
156 const struct net_device *in,
157 const struct net_device *out,
158 int (*okfn)(struct sk_buff *))
160 /* Previously seen (loopback)? Ignore. Do this before
165 /* Gather fragments. */
166 if (ip_hdr(*pskb)->frag_off & htons(IP_MF | IP_OFFSET)) {
167 *pskb = nf_ct_ipv4_gather_frags(*pskb,
168 hooknum == NF_IP_PRE_ROUTING ?
169 IP_DEFRAG_CONNTRACK_IN :
170 IP_DEFRAG_CONNTRACK_OUT);
177 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
178 struct sk_buff **pskb,
179 const struct net_device *in,
180 const struct net_device *out,
181 int (*okfn)(struct sk_buff *))
183 return nf_conntrack_in(PF_INET, hooknum, pskb);
186 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
187 struct sk_buff **pskb,
188 const struct net_device *in,
189 const struct net_device *out,
190 int (*okfn)(struct sk_buff *))
192 /* root is playing with raw sockets. */
193 if ((*pskb)->len < sizeof(struct iphdr)
194 || ip_hdrlen(*pskb) < sizeof(struct iphdr)) {
196 printk("ipt_hook: happy cracking.\n");
199 return nf_conntrack_in(PF_INET, hooknum, pskb);
202 /* Connection tracking may drop packets, but never alters them, so
203 make it the first hook. */
204 static struct nf_hook_ops ipv4_conntrack_ops[] = {
206 .hook = ipv4_conntrack_defrag,
207 .owner = THIS_MODULE,
209 .hooknum = NF_IP_PRE_ROUTING,
210 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
213 .hook = ipv4_conntrack_in,
214 .owner = THIS_MODULE,
216 .hooknum = NF_IP_PRE_ROUTING,
217 .priority = NF_IP_PRI_CONNTRACK,
220 .hook = ipv4_conntrack_defrag,
221 .owner = THIS_MODULE,
223 .hooknum = NF_IP_LOCAL_OUT,
224 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
227 .hook = ipv4_conntrack_local,
228 .owner = THIS_MODULE,
230 .hooknum = NF_IP_LOCAL_OUT,
231 .priority = NF_IP_PRI_CONNTRACK,
234 .hook = ipv4_conntrack_help,
235 .owner = THIS_MODULE,
237 .hooknum = NF_IP_POST_ROUTING,
238 .priority = NF_IP_PRI_CONNTRACK_HELPER,
241 .hook = ipv4_conntrack_help,
242 .owner = THIS_MODULE,
244 .hooknum = NF_IP_LOCAL_IN,
245 .priority = NF_IP_PRI_CONNTRACK_HELPER,
248 .hook = ipv4_confirm,
249 .owner = THIS_MODULE,
251 .hooknum = NF_IP_POST_ROUTING,
252 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
255 .hook = ipv4_confirm,
256 .owner = THIS_MODULE,
258 .hooknum = NF_IP_LOCAL_IN,
259 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
263 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
264 static int log_invalid_proto_min = 0;
265 static int log_invalid_proto_max = 255;
267 static ctl_table ip_ct_sysctl_table[] = {
269 .ctl_name = NET_IPV4_NF_CONNTRACK_MAX,
270 .procname = "ip_conntrack_max",
271 .data = &nf_conntrack_max,
272 .maxlen = sizeof(int),
274 .proc_handler = &proc_dointvec,
277 .ctl_name = NET_IPV4_NF_CONNTRACK_COUNT,
278 .procname = "ip_conntrack_count",
279 .data = &nf_conntrack_count,
280 .maxlen = sizeof(int),
282 .proc_handler = &proc_dointvec,
285 .ctl_name = NET_IPV4_NF_CONNTRACK_BUCKETS,
286 .procname = "ip_conntrack_buckets",
287 .data = &nf_conntrack_htable_size,
288 .maxlen = sizeof(unsigned int),
290 .proc_handler = &proc_dointvec,
293 .ctl_name = NET_IPV4_NF_CONNTRACK_CHECKSUM,
294 .procname = "ip_conntrack_checksum",
295 .data = &nf_conntrack_checksum,
296 .maxlen = sizeof(int),
298 .proc_handler = &proc_dointvec,
301 .ctl_name = NET_IPV4_NF_CONNTRACK_LOG_INVALID,
302 .procname = "ip_conntrack_log_invalid",
303 .data = &nf_ct_log_invalid,
304 .maxlen = sizeof(unsigned int),
306 .proc_handler = &proc_dointvec_minmax,
307 .strategy = &sysctl_intvec,
308 .extra1 = &log_invalid_proto_min,
309 .extra2 = &log_invalid_proto_max,
315 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
317 /* Fast function for those who don't want to parse /proc (and I don't
319 /* Reversing the socket's dst/src point of view gives us the reply
322 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
324 struct inet_sock *inet = inet_sk(sk);
325 struct nf_conntrack_tuple_hash *h;
326 struct nf_conntrack_tuple tuple;
328 NF_CT_TUPLE_U_BLANK(&tuple);
329 tuple.src.u3.ip = inet->rcv_saddr;
330 tuple.src.u.tcp.port = inet->sport;
331 tuple.dst.u3.ip = inet->daddr;
332 tuple.dst.u.tcp.port = inet->dport;
333 tuple.src.l3num = PF_INET;
334 tuple.dst.protonum = IPPROTO_TCP;
336 /* We only do TCP at the moment: is there a better way? */
337 if (strcmp(sk->sk_prot->name, "TCP")) {
338 DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
342 if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
343 DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
344 *len, sizeof(struct sockaddr_in));
348 h = nf_conntrack_find_get(&tuple, NULL);
350 struct sockaddr_in sin;
351 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
353 sin.sin_family = AF_INET;
354 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
355 .tuple.dst.u.tcp.port;
356 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
358 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
360 DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
361 NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
363 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
368 DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
369 NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
370 NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
374 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
376 #include <linux/netfilter/nfnetlink.h>
377 #include <linux/netfilter/nfnetlink_conntrack.h>
379 static int ipv4_tuple_to_nfattr(struct sk_buff *skb,
380 const struct nf_conntrack_tuple *tuple)
382 NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
384 NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
392 static const size_t cta_min_ip[CTA_IP_MAX] = {
393 [CTA_IP_V4_SRC-1] = sizeof(u_int32_t),
394 [CTA_IP_V4_DST-1] = sizeof(u_int32_t),
397 static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
398 struct nf_conntrack_tuple *t)
400 if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1])
403 if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
406 t->src.u3.ip = *(__be32 *)NFA_DATA(tb[CTA_IP_V4_SRC-1]);
407 t->dst.u3.ip = *(__be32 *)NFA_DATA(tb[CTA_IP_V4_DST-1]);
413 static struct nf_sockopt_ops so_getorigdst = {
415 .get_optmin = SO_ORIGINAL_DST,
416 .get_optmax = SO_ORIGINAL_DST+1,
420 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
423 .pkt_to_tuple = ipv4_pkt_to_tuple,
424 .invert_tuple = ipv4_invert_tuple,
425 .print_tuple = ipv4_print_tuple,
426 .print_conntrack = ipv4_print_conntrack,
427 .prepare = ipv4_prepare,
428 .get_features = ipv4_get_features,
429 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
430 .tuple_to_nfattr = ipv4_tuple_to_nfattr,
431 .nfattr_to_tuple = ipv4_nfattr_to_tuple,
433 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
434 .ctl_table_path = nf_net_ipv4_netfilter_sysctl_path,
435 .ctl_table = ip_ct_sysctl_table,
440 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
441 MODULE_ALIAS("ip_conntrack");
442 MODULE_LICENSE("GPL");
444 static int __init nf_conntrack_l3proto_ipv4_init(void)
450 ret = nf_register_sockopt(&so_getorigdst);
452 printk(KERN_ERR "Unable to register netfilter socket option\n");
456 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
458 printk("nf_conntrack_ipv4: can't register tcp.\n");
459 goto cleanup_sockopt;
462 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
464 printk("nf_conntrack_ipv4: can't register udp.\n");
468 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
470 printk("nf_conntrack_ipv4: can't register icmp.\n");
474 ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
476 printk("nf_conntrack_ipv4: can't register ipv4\n");
480 ret = nf_register_hooks(ipv4_conntrack_ops,
481 ARRAY_SIZE(ipv4_conntrack_ops));
483 printk("nf_conntrack_ipv4: can't register hooks.\n");
486 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
487 ret = nf_conntrack_ipv4_compat_init();
492 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
494 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
497 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
499 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
501 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
503 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
505 nf_unregister_sockopt(&so_getorigdst);
509 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
512 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
513 nf_conntrack_ipv4_compat_fini();
515 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
516 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
517 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
518 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
519 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
520 nf_unregister_sockopt(&so_getorigdst);
523 module_init(nf_conntrack_l3proto_ipv4_init);
524 module_exit(nf_conntrack_l3proto_ipv4_fini);