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 __read_mostly = {
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);