2 /* (C) 1999-2001 Paul `Rusty' Russell
3 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/types.h>
12 #include <linux/netfilter.h>
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/icmp.h>
16 #include <linux/sysctl.h>
17 #include <net/route.h>
20 #include <linux/netfilter_ipv4.h>
21 #include <net/netfilter/nf_conntrack.h>
22 #include <net/netfilter/nf_conntrack_helper.h>
23 #include <net/netfilter/nf_conntrack_l4proto.h>
24 #include <net/netfilter/nf_conntrack_l3proto.h>
25 #include <net/netfilter/nf_conntrack_core.h>
26 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
27 #include <net/netfilter/nf_nat_helper.h>
28 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
30 int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb,
32 enum ip_conntrack_info ctinfo);
33 EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook);
35 static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
36 struct nf_conntrack_tuple *tuple)
40 ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
41 sizeof(u_int32_t) * 2, _addrs);
45 tuple->src.u3.ip = ap[0];
46 tuple->dst.u3.ip = ap[1];
51 static bool ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
52 const struct nf_conntrack_tuple *orig)
54 tuple->src.u3.ip = orig->dst.u3.ip;
55 tuple->dst.u3.ip = orig->src.u3.ip;
60 static int ipv4_print_tuple(struct seq_file *s,
61 const struct nf_conntrack_tuple *tuple)
63 return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
64 NIPQUAD(tuple->src.u3.ip),
65 NIPQUAD(tuple->dst.u3.ip));
68 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
69 unsigned int *dataoff, u_int8_t *protonum)
71 const struct iphdr *iph;
74 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
78 /* Conntrack defragments packets, we might still see fragments
79 * inside ICMP packets though. */
80 if (iph->frag_off & htons(IP_OFFSET))
83 *dataoff = nhoff + (iph->ihl << 2);
84 *protonum = iph->protocol;
89 static unsigned int ipv4_confirm(unsigned int hooknum,
91 const struct net_device *in,
92 const struct net_device *out,
93 int (*okfn)(struct sk_buff *))
96 enum ip_conntrack_info ctinfo;
97 const struct nf_conn_help *help;
98 const struct nf_conntrack_helper *helper;
101 /* This is where we call the helper: as the packet goes out. */
102 ct = nf_ct_get(skb, &ctinfo);
103 if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
106 help = nfct_help(ct);
110 /* rcu_read_lock()ed by nf_hook_slow */
111 helper = rcu_dereference(help->helper);
115 ret = helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
117 if (ret != NF_ACCEPT)
120 if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status)) {
121 typeof(nf_nat_seq_adjust_hook) seq_adjust;
123 seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);
124 if (!seq_adjust || !seq_adjust(skb, ct, ctinfo))
128 /* We've seen it coming out the other side: confirm it */
129 return nf_conntrack_confirm(skb);
132 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
134 const struct net_device *in,
135 const struct net_device *out,
136 int (*okfn)(struct sk_buff *))
138 return nf_conntrack_in(dev_net(in), PF_INET, hooknum, skb);
141 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
143 const struct net_device *in,
144 const struct net_device *out,
145 int (*okfn)(struct sk_buff *))
147 /* root is playing with raw sockets. */
148 if (skb->len < sizeof(struct iphdr) ||
149 ip_hdrlen(skb) < sizeof(struct iphdr)) {
151 printk("ipt_hook: happy cracking.\n");
154 return nf_conntrack_in(dev_net(out), PF_INET, hooknum, skb);
157 /* Connection tracking may drop packets, but never alters them, so
158 make it the first hook. */
159 static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
161 .hook = ipv4_conntrack_in,
162 .owner = THIS_MODULE,
164 .hooknum = NF_INET_PRE_ROUTING,
165 .priority = NF_IP_PRI_CONNTRACK,
168 .hook = ipv4_conntrack_local,
169 .owner = THIS_MODULE,
171 .hooknum = NF_INET_LOCAL_OUT,
172 .priority = NF_IP_PRI_CONNTRACK,
175 .hook = ipv4_confirm,
176 .owner = THIS_MODULE,
178 .hooknum = NF_INET_POST_ROUTING,
179 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
182 .hook = ipv4_confirm,
183 .owner = THIS_MODULE,
185 .hooknum = NF_INET_LOCAL_IN,
186 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
190 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
191 static int log_invalid_proto_min = 0;
192 static int log_invalid_proto_max = 255;
194 static ctl_table ip_ct_sysctl_table[] = {
196 .ctl_name = NET_IPV4_NF_CONNTRACK_MAX,
197 .procname = "ip_conntrack_max",
198 .data = &nf_conntrack_max,
199 .maxlen = sizeof(int),
201 .proc_handler = &proc_dointvec,
204 .ctl_name = NET_IPV4_NF_CONNTRACK_COUNT,
205 .procname = "ip_conntrack_count",
206 .data = &init_net.ct.count,
207 .maxlen = sizeof(int),
209 .proc_handler = &proc_dointvec,
212 .ctl_name = NET_IPV4_NF_CONNTRACK_BUCKETS,
213 .procname = "ip_conntrack_buckets",
214 .data = &nf_conntrack_htable_size,
215 .maxlen = sizeof(unsigned int),
217 .proc_handler = &proc_dointvec,
220 .ctl_name = NET_IPV4_NF_CONNTRACK_CHECKSUM,
221 .procname = "ip_conntrack_checksum",
222 .data = &init_net.ct.sysctl_checksum,
223 .maxlen = sizeof(int),
225 .proc_handler = &proc_dointvec,
228 .ctl_name = NET_IPV4_NF_CONNTRACK_LOG_INVALID,
229 .procname = "ip_conntrack_log_invalid",
230 .data = &init_net.ct.sysctl_log_invalid,
231 .maxlen = sizeof(unsigned int),
233 .proc_handler = &proc_dointvec_minmax,
234 .strategy = &sysctl_intvec,
235 .extra1 = &log_invalid_proto_min,
236 .extra2 = &log_invalid_proto_max,
242 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
244 /* Fast function for those who don't want to parse /proc (and I don't
246 /* Reversing the socket's dst/src point of view gives us the reply
249 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
251 const struct inet_sock *inet = inet_sk(sk);
252 const struct nf_conntrack_tuple_hash *h;
253 struct nf_conntrack_tuple tuple;
255 memset(&tuple, 0, sizeof(tuple));
256 tuple.src.u3.ip = inet->rcv_saddr;
257 tuple.src.u.tcp.port = inet->sport;
258 tuple.dst.u3.ip = inet->daddr;
259 tuple.dst.u.tcp.port = inet->dport;
260 tuple.src.l3num = PF_INET;
261 tuple.dst.protonum = IPPROTO_TCP;
263 /* We only do TCP at the moment: is there a better way? */
264 if (strcmp(sk->sk_prot->name, "TCP")) {
265 pr_debug("SO_ORIGINAL_DST: Not a TCP socket\n");
269 if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
270 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
271 *len, sizeof(struct sockaddr_in));
275 h = nf_conntrack_find_get(sock_net(sk), &tuple);
277 struct sockaddr_in sin;
278 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
280 sin.sin_family = AF_INET;
281 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
282 .tuple.dst.u.tcp.port;
283 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
285 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
287 pr_debug("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
288 NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
290 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
295 pr_debug("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
296 NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
297 NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
301 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
303 #include <linux/netfilter/nfnetlink.h>
304 #include <linux/netfilter/nfnetlink_conntrack.h>
306 static int ipv4_tuple_to_nlattr(struct sk_buff *skb,
307 const struct nf_conntrack_tuple *tuple)
309 NLA_PUT_BE32(skb, CTA_IP_V4_SRC, tuple->src.u3.ip);
310 NLA_PUT_BE32(skb, CTA_IP_V4_DST, tuple->dst.u3.ip);
317 static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
318 [CTA_IP_V4_SRC] = { .type = NLA_U32 },
319 [CTA_IP_V4_DST] = { .type = NLA_U32 },
322 static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
323 struct nf_conntrack_tuple *t)
325 if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
328 t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]);
329 t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]);
335 static struct nf_sockopt_ops so_getorigdst = {
337 .get_optmin = SO_ORIGINAL_DST,
338 .get_optmax = SO_ORIGINAL_DST+1,
340 .owner = THIS_MODULE,
343 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
346 .pkt_to_tuple = ipv4_pkt_to_tuple,
347 .invert_tuple = ipv4_invert_tuple,
348 .print_tuple = ipv4_print_tuple,
349 .get_l4proto = ipv4_get_l4proto,
350 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
351 .tuple_to_nlattr = ipv4_tuple_to_nlattr,
352 .nlattr_to_tuple = ipv4_nlattr_to_tuple,
353 .nla_policy = ipv4_nla_policy,
355 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
356 .ctl_table_path = nf_net_ipv4_netfilter_sysctl_path,
357 .ctl_table = ip_ct_sysctl_table,
362 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
363 &nf_conntrack_htable_size, 0600);
365 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
366 MODULE_ALIAS("ip_conntrack");
367 MODULE_LICENSE("GPL");
369 static int __init nf_conntrack_l3proto_ipv4_init(void)
374 nf_defrag_ipv4_enable();
376 ret = nf_register_sockopt(&so_getorigdst);
378 printk(KERN_ERR "Unable to register netfilter socket option\n");
382 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
384 printk("nf_conntrack_ipv4: can't register tcp.\n");
385 goto cleanup_sockopt;
388 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
390 printk("nf_conntrack_ipv4: can't register udp.\n");
394 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
396 printk("nf_conntrack_ipv4: can't register icmp.\n");
400 ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
402 printk("nf_conntrack_ipv4: can't register ipv4\n");
406 ret = nf_register_hooks(ipv4_conntrack_ops,
407 ARRAY_SIZE(ipv4_conntrack_ops));
409 printk("nf_conntrack_ipv4: can't register hooks.\n");
412 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
413 ret = nf_conntrack_ipv4_compat_init();
418 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
420 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
423 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
425 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
427 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
429 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
431 nf_unregister_sockopt(&so_getorigdst);
435 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
438 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
439 nf_conntrack_ipv4_compat_fini();
441 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
442 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
443 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
444 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
445 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
446 nf_unregister_sockopt(&so_getorigdst);
449 module_init(nf_conntrack_l3proto_ipv4_init);
450 module_exit(nf_conntrack_l3proto_ipv4_fini);
452 void need_ipv4_conntrack(void)
456 EXPORT_SYMBOL_GPL(need_ipv4_conntrack);