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)
32 ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
33 sizeof(u_int32_t) * 2, _addrs);
37 tuple->src.u3.ip = ap[0];
38 tuple->dst.u3.ip = ap[1];
43 static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
44 const struct nf_conntrack_tuple *orig)
46 tuple->src.u3.ip = orig->dst.u3.ip;
47 tuple->dst.u3.ip = orig->src.u3.ip;
52 static int ipv4_print_tuple(struct seq_file *s,
53 const struct nf_conntrack_tuple *tuple)
55 return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
56 NIPQUAD(tuple->src.u3.ip),
57 NIPQUAD(tuple->dst.u3.ip));
60 /* Returns new sk_buff, or NULL */
61 static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
68 err = ip_defrag(skb, user);
72 ip_send_check(ip_hdr(skb));
77 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
78 unsigned int *dataoff, u_int8_t *protonum)
80 const struct iphdr *iph;
83 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
87 /* Conntrack defragments packets, we might still see fragments
88 * inside ICMP packets though. */
89 if (iph->frag_off & htons(IP_OFFSET))
92 *dataoff = nhoff + (iph->ihl << 2);
93 *protonum = iph->protocol;
98 static unsigned int ipv4_confirm(unsigned int hooknum,
100 const struct net_device *in,
101 const struct net_device *out,
102 int (*okfn)(struct sk_buff *))
104 /* We've seen it coming out the other side: confirm it */
105 return nf_conntrack_confirm(skb);
108 static unsigned int ipv4_conntrack_help(unsigned int hooknum,
110 const struct net_device *in,
111 const struct net_device *out,
112 int (*okfn)(struct sk_buff *))
115 enum ip_conntrack_info ctinfo;
116 const struct nf_conn_help *help;
117 const struct nf_conntrack_helper *helper;
119 /* This is where we call the helper: as the packet goes out. */
120 ct = nf_ct_get(skb, &ctinfo);
121 if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
124 help = nfct_help(ct);
127 /* rcu_read_lock()ed by nf_hook_slow */
128 helper = rcu_dereference(help->helper);
131 return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
135 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
137 const struct net_device *in,
138 const struct net_device *out,
139 int (*okfn)(struct sk_buff *))
141 /* Previously seen (loopback)? Ignore. Do this before
146 /* Gather fragments. */
147 if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
148 if (nf_ct_ipv4_gather_frags(skb,
149 hooknum == NF_INET_PRE_ROUTING ?
150 IP_DEFRAG_CONNTRACK_IN :
151 IP_DEFRAG_CONNTRACK_OUT))
157 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
159 const struct net_device *in,
160 const struct net_device *out,
161 int (*okfn)(struct sk_buff *))
163 return nf_conntrack_in(PF_INET, hooknum, skb);
166 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
168 const struct net_device *in,
169 const struct net_device *out,
170 int (*okfn)(struct sk_buff *))
172 /* root is playing with raw sockets. */
173 if (skb->len < sizeof(struct iphdr) ||
174 ip_hdrlen(skb) < sizeof(struct iphdr)) {
176 printk("ipt_hook: happy cracking.\n");
179 return nf_conntrack_in(PF_INET, hooknum, skb);
182 /* Connection tracking may drop packets, but never alters them, so
183 make it the first hook. */
184 static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
186 .hook = ipv4_conntrack_defrag,
187 .owner = THIS_MODULE,
189 .hooknum = NF_INET_PRE_ROUTING,
190 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
193 .hook = ipv4_conntrack_in,
194 .owner = THIS_MODULE,
196 .hooknum = NF_INET_PRE_ROUTING,
197 .priority = NF_IP_PRI_CONNTRACK,
200 .hook = ipv4_conntrack_defrag,
201 .owner = THIS_MODULE,
203 .hooknum = NF_INET_LOCAL_OUT,
204 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
207 .hook = ipv4_conntrack_local,
208 .owner = THIS_MODULE,
210 .hooknum = NF_INET_LOCAL_OUT,
211 .priority = NF_IP_PRI_CONNTRACK,
214 .hook = ipv4_conntrack_help,
215 .owner = THIS_MODULE,
217 .hooknum = NF_INET_POST_ROUTING,
218 .priority = NF_IP_PRI_CONNTRACK_HELPER,
221 .hook = ipv4_conntrack_help,
222 .owner = THIS_MODULE,
224 .hooknum = NF_INET_LOCAL_IN,
225 .priority = NF_IP_PRI_CONNTRACK_HELPER,
228 .hook = ipv4_confirm,
229 .owner = THIS_MODULE,
231 .hooknum = NF_INET_POST_ROUTING,
232 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
235 .hook = ipv4_confirm,
236 .owner = THIS_MODULE,
238 .hooknum = NF_INET_LOCAL_IN,
239 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
243 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
244 static int log_invalid_proto_min = 0;
245 static int log_invalid_proto_max = 255;
247 static ctl_table ip_ct_sysctl_table[] = {
249 .ctl_name = NET_IPV4_NF_CONNTRACK_MAX,
250 .procname = "ip_conntrack_max",
251 .data = &nf_conntrack_max,
252 .maxlen = sizeof(int),
254 .proc_handler = &proc_dointvec,
257 .ctl_name = NET_IPV4_NF_CONNTRACK_COUNT,
258 .procname = "ip_conntrack_count",
259 .data = &nf_conntrack_count,
260 .maxlen = sizeof(int),
262 .proc_handler = &proc_dointvec,
265 .ctl_name = NET_IPV4_NF_CONNTRACK_BUCKETS,
266 .procname = "ip_conntrack_buckets",
267 .data = &nf_conntrack_htable_size,
268 .maxlen = sizeof(unsigned int),
270 .proc_handler = &proc_dointvec,
273 .ctl_name = NET_IPV4_NF_CONNTRACK_CHECKSUM,
274 .procname = "ip_conntrack_checksum",
275 .data = &nf_conntrack_checksum,
276 .maxlen = sizeof(int),
278 .proc_handler = &proc_dointvec,
281 .ctl_name = NET_IPV4_NF_CONNTRACK_LOG_INVALID,
282 .procname = "ip_conntrack_log_invalid",
283 .data = &nf_ct_log_invalid,
284 .maxlen = sizeof(unsigned int),
286 .proc_handler = &proc_dointvec_minmax,
287 .strategy = &sysctl_intvec,
288 .extra1 = &log_invalid_proto_min,
289 .extra2 = &log_invalid_proto_max,
295 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
297 /* Fast function for those who don't want to parse /proc (and I don't
299 /* Reversing the socket's dst/src point of view gives us the reply
302 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
304 const struct inet_sock *inet = inet_sk(sk);
305 const struct nf_conntrack_tuple_hash *h;
306 struct nf_conntrack_tuple tuple;
308 NF_CT_TUPLE_U_BLANK(&tuple);
309 tuple.src.u3.ip = inet->rcv_saddr;
310 tuple.src.u.tcp.port = inet->sport;
311 tuple.dst.u3.ip = inet->daddr;
312 tuple.dst.u.tcp.port = inet->dport;
313 tuple.src.l3num = PF_INET;
314 tuple.dst.protonum = IPPROTO_TCP;
316 /* We only do TCP at the moment: is there a better way? */
317 if (strcmp(sk->sk_prot->name, "TCP")) {
318 pr_debug("SO_ORIGINAL_DST: Not a TCP socket\n");
322 if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
323 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
324 *len, sizeof(struct sockaddr_in));
328 h = nf_conntrack_find_get(&tuple);
330 struct sockaddr_in sin;
331 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
333 sin.sin_family = AF_INET;
334 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
335 .tuple.dst.u.tcp.port;
336 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
338 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
340 pr_debug("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
341 NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
343 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
348 pr_debug("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
349 NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
350 NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
354 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
356 #include <linux/netfilter/nfnetlink.h>
357 #include <linux/netfilter/nfnetlink_conntrack.h>
359 static int ipv4_tuple_to_nlattr(struct sk_buff *skb,
360 const struct nf_conntrack_tuple *tuple)
362 NLA_PUT_BE32(skb, CTA_IP_V4_SRC, tuple->src.u3.ip);
363 NLA_PUT_BE32(skb, CTA_IP_V4_DST, tuple->dst.u3.ip);
370 static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
371 [CTA_IP_V4_SRC] = { .type = NLA_U32 },
372 [CTA_IP_V4_DST] = { .type = NLA_U32 },
375 static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
376 struct nf_conntrack_tuple *t)
378 if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
381 t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]);
382 t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]);
388 static struct nf_sockopt_ops so_getorigdst = {
390 .get_optmin = SO_ORIGINAL_DST,
391 .get_optmax = SO_ORIGINAL_DST+1,
393 .owner = THIS_MODULE,
396 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
399 .pkt_to_tuple = ipv4_pkt_to_tuple,
400 .invert_tuple = ipv4_invert_tuple,
401 .print_tuple = ipv4_print_tuple,
402 .get_l4proto = ipv4_get_l4proto,
403 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
404 .tuple_to_nlattr = ipv4_tuple_to_nlattr,
405 .nlattr_to_tuple = ipv4_nlattr_to_tuple,
406 .nla_policy = ipv4_nla_policy,
408 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
409 .ctl_table_path = nf_net_ipv4_netfilter_sysctl_path,
410 .ctl_table = ip_ct_sysctl_table,
415 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
416 &nf_conntrack_htable_size, 0600);
418 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
419 MODULE_ALIAS("ip_conntrack");
420 MODULE_LICENSE("GPL");
422 static int __init nf_conntrack_l3proto_ipv4_init(void)
428 ret = nf_register_sockopt(&so_getorigdst);
430 printk(KERN_ERR "Unable to register netfilter socket option\n");
434 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
436 printk("nf_conntrack_ipv4: can't register tcp.\n");
437 goto cleanup_sockopt;
440 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
442 printk("nf_conntrack_ipv4: can't register udp.\n");
446 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
448 printk("nf_conntrack_ipv4: can't register icmp.\n");
452 ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
454 printk("nf_conntrack_ipv4: can't register ipv4\n");
458 ret = nf_register_hooks(ipv4_conntrack_ops,
459 ARRAY_SIZE(ipv4_conntrack_ops));
461 printk("nf_conntrack_ipv4: can't register hooks.\n");
464 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
465 ret = nf_conntrack_ipv4_compat_init();
470 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
472 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
475 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
477 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
479 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
481 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
483 nf_unregister_sockopt(&so_getorigdst);
487 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
490 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
491 nf_conntrack_ipv4_compat_fini();
493 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
494 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
495 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
496 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
497 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
498 nf_unregister_sockopt(&so_getorigdst);
501 module_init(nf_conntrack_l3proto_ipv4_init);
502 module_exit(nf_conntrack_l3proto_ipv4_fini);
504 void need_ipv4_conntrack(void)
508 EXPORT_SYMBOL_GPL(need_ipv4_conntrack);