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_zones.h>
26 #include <net/netfilter/nf_conntrack_core.h>
27 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
28 #include <net/netfilter/nf_nat_helper.h>
29 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
30 #include <net/netfilter/nf_log.h>
32 int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb,
34 enum ip_conntrack_info ctinfo);
35 EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook);
37 static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
38 struct nf_conntrack_tuple *tuple)
42 ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
43 sizeof(u_int32_t) * 2, _addrs);
47 tuple->src.u3.ip = ap[0];
48 tuple->dst.u3.ip = ap[1];
53 static bool ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
54 const struct nf_conntrack_tuple *orig)
56 tuple->src.u3.ip = orig->dst.u3.ip;
57 tuple->dst.u3.ip = orig->src.u3.ip;
62 static int ipv4_print_tuple(struct seq_file *s,
63 const struct nf_conntrack_tuple *tuple)
65 return seq_printf(s, "src=%pI4 dst=%pI4 ",
66 &tuple->src.u3.ip, &tuple->dst.u3.ip);
69 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
70 unsigned int *dataoff, u_int8_t *protonum)
72 const struct iphdr *iph;
75 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
79 /* Conntrack defragments packets, we might still see fragments
80 * inside ICMP packets though. */
81 if (iph->frag_off & htons(IP_OFFSET))
84 *dataoff = nhoff + (iph->ihl << 2);
85 *protonum = iph->protocol;
90 static unsigned int ipv4_confirm(unsigned int hooknum,
92 const struct net_device *in,
93 const struct net_device *out,
94 int (*okfn)(struct sk_buff *))
97 enum ip_conntrack_info ctinfo;
98 const struct nf_conn_help *help;
99 const struct nf_conntrack_helper *helper;
102 /* This is where we call the helper: as the packet goes out. */
103 ct = nf_ct_get(skb, &ctinfo);
104 if (!ct || ctinfo == IP_CT_RELATED_REPLY)
107 help = nfct_help(ct);
111 /* rcu_read_lock()ed by nf_hook_slow */
112 helper = rcu_dereference(help->helper);
116 ret = helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
118 if (ret != NF_ACCEPT) {
119 nf_log_packet(NFPROTO_IPV4, hooknum, skb, in, out, NULL,
120 "nf_ct_%s: dropping packet", helper->name);
124 /* adjust seqs for loopback traffic only in outgoing direction */
125 if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
126 !nf_is_loopback_packet(skb)) {
127 typeof(nf_nat_seq_adjust_hook) seq_adjust;
129 seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);
130 if (!seq_adjust || !seq_adjust(skb, ct, ctinfo)) {
131 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
136 /* We've seen it coming out the other side: confirm it */
137 return nf_conntrack_confirm(skb);
140 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
142 const struct net_device *in,
143 const struct net_device *out,
144 int (*okfn)(struct sk_buff *))
146 return nf_conntrack_in(dev_net(in), PF_INET, hooknum, skb);
149 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
151 const struct net_device *in,
152 const struct net_device *out,
153 int (*okfn)(struct sk_buff *))
155 /* root is playing with raw sockets. */
156 if (skb->len < sizeof(struct iphdr) ||
157 ip_hdrlen(skb) < sizeof(struct iphdr))
159 return nf_conntrack_in(dev_net(out), PF_INET, hooknum, skb);
162 /* Connection tracking may drop packets, but never alters them, so
163 make it the first hook. */
164 static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
166 .hook = ipv4_conntrack_in,
167 .owner = THIS_MODULE,
169 .hooknum = NF_INET_PRE_ROUTING,
170 .priority = NF_IP_PRI_CONNTRACK,
173 .hook = ipv4_conntrack_local,
174 .owner = THIS_MODULE,
176 .hooknum = NF_INET_LOCAL_OUT,
177 .priority = NF_IP_PRI_CONNTRACK,
180 .hook = ipv4_confirm,
181 .owner = THIS_MODULE,
183 .hooknum = NF_INET_POST_ROUTING,
184 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
187 .hook = ipv4_confirm,
188 .owner = THIS_MODULE,
190 .hooknum = NF_INET_LOCAL_IN,
191 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
195 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
196 static int log_invalid_proto_min = 0;
197 static int log_invalid_proto_max = 255;
199 static ctl_table ip_ct_sysctl_table[] = {
201 .procname = "ip_conntrack_max",
202 .data = &nf_conntrack_max,
203 .maxlen = sizeof(int),
205 .proc_handler = proc_dointvec,
208 .procname = "ip_conntrack_count",
209 .data = &init_net.ct.count,
210 .maxlen = sizeof(int),
212 .proc_handler = proc_dointvec,
215 .procname = "ip_conntrack_buckets",
216 .data = &init_net.ct.htable_size,
217 .maxlen = sizeof(unsigned int),
219 .proc_handler = proc_dointvec,
222 .procname = "ip_conntrack_checksum",
223 .data = &init_net.ct.sysctl_checksum,
224 .maxlen = sizeof(int),
226 .proc_handler = proc_dointvec,
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 .extra1 = &log_invalid_proto_min,
235 .extra2 = &log_invalid_proto_max,
239 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
241 /* Fast function for those who don't want to parse /proc (and I don't
243 /* Reversing the socket's dst/src point of view gives us the reply
246 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
248 const struct inet_sock *inet = inet_sk(sk);
249 const struct nf_conntrack_tuple_hash *h;
250 struct nf_conntrack_tuple tuple;
252 memset(&tuple, 0, sizeof(tuple));
253 tuple.src.u3.ip = inet->inet_rcv_saddr;
254 tuple.src.u.tcp.port = inet->inet_sport;
255 tuple.dst.u3.ip = inet->inet_daddr;
256 tuple.dst.u.tcp.port = inet->inet_dport;
257 tuple.src.l3num = PF_INET;
258 tuple.dst.protonum = sk->sk_protocol;
260 /* We only do TCP and SCTP at the moment: is there a better way? */
261 if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP) {
262 pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
266 if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
267 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
268 *len, sizeof(struct sockaddr_in));
272 h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple);
274 struct sockaddr_in sin;
275 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
277 sin.sin_family = AF_INET;
278 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
279 .tuple.dst.u.tcp.port;
280 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
282 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
284 pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
285 &sin.sin_addr.s_addr, ntohs(sin.sin_port));
287 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
292 pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
293 &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port),
294 &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port));
298 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
300 #include <linux/netfilter/nfnetlink.h>
301 #include <linux/netfilter/nfnetlink_conntrack.h>
303 static int ipv4_tuple_to_nlattr(struct sk_buff *skb,
304 const struct nf_conntrack_tuple *tuple)
306 NLA_PUT_BE32(skb, CTA_IP_V4_SRC, tuple->src.u3.ip);
307 NLA_PUT_BE32(skb, CTA_IP_V4_DST, tuple->dst.u3.ip);
314 static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
315 [CTA_IP_V4_SRC] = { .type = NLA_U32 },
316 [CTA_IP_V4_DST] = { .type = NLA_U32 },
319 static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
320 struct nf_conntrack_tuple *t)
322 if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
325 t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]);
326 t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]);
331 static int ipv4_nlattr_tuple_size(void)
333 return nla_policy_len(ipv4_nla_policy, CTA_IP_MAX + 1);
337 static struct nf_sockopt_ops so_getorigdst = {
339 .get_optmin = SO_ORIGINAL_DST,
340 .get_optmax = SO_ORIGINAL_DST+1,
342 .owner = THIS_MODULE,
345 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
348 .pkt_to_tuple = ipv4_pkt_to_tuple,
349 .invert_tuple = ipv4_invert_tuple,
350 .print_tuple = ipv4_print_tuple,
351 .get_l4proto = ipv4_get_l4proto,
352 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
353 .tuple_to_nlattr = ipv4_tuple_to_nlattr,
354 .nlattr_tuple_size = ipv4_nlattr_tuple_size,
355 .nlattr_to_tuple = ipv4_nlattr_to_tuple,
356 .nla_policy = ipv4_nla_policy,
358 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
359 .ctl_table_path = nf_net_ipv4_netfilter_sysctl_path,
360 .ctl_table = ip_ct_sysctl_table,
365 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
366 &nf_conntrack_htable_size, 0600);
368 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
369 MODULE_ALIAS("ip_conntrack");
370 MODULE_LICENSE("GPL");
372 static int __init nf_conntrack_l3proto_ipv4_init(void)
377 nf_defrag_ipv4_enable();
379 ret = nf_register_sockopt(&so_getorigdst);
381 printk(KERN_ERR "Unable to register netfilter socket option\n");
385 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
387 pr_err("nf_conntrack_ipv4: can't register tcp.\n");
388 goto cleanup_sockopt;
391 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
393 pr_err("nf_conntrack_ipv4: can't register udp.\n");
397 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
399 pr_err("nf_conntrack_ipv4: can't register icmp.\n");
403 ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
405 pr_err("nf_conntrack_ipv4: can't register ipv4\n");
409 ret = nf_register_hooks(ipv4_conntrack_ops,
410 ARRAY_SIZE(ipv4_conntrack_ops));
412 pr_err("nf_conntrack_ipv4: can't register hooks.\n");
415 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
416 ret = nf_conntrack_ipv4_compat_init();
421 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
423 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
426 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
428 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
430 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
432 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
434 nf_unregister_sockopt(&so_getorigdst);
438 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
441 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
442 nf_conntrack_ipv4_compat_fini();
444 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
445 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
446 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
447 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
448 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
449 nf_unregister_sockopt(&so_getorigdst);
452 module_init(nf_conntrack_l3proto_ipv4_init);
453 module_exit(nf_conntrack_l3proto_ipv4_fini);
455 void need_ipv4_conntrack(void)
459 EXPORT_SYMBOL_GPL(need_ipv4_conntrack);