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>
29 #include <net/netfilter/nf_log.h>
31 int (*nf_nat_seq_adjust_hook
)(struct sk_buff
*skb
,
33 enum ip_conntrack_info ctinfo
);
34 EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook
);
36 static bool ipv4_pkt_to_tuple(const struct sk_buff
*skb
, unsigned int nhoff
,
37 struct nf_conntrack_tuple
*tuple
)
41 ap
= skb_header_pointer(skb
, nhoff
+ offsetof(struct iphdr
, saddr
),
42 sizeof(u_int32_t
) * 2, _addrs
);
46 tuple
->src
.u3
.ip
= ap
[0];
47 tuple
->dst
.u3
.ip
= ap
[1];
52 static bool ipv4_invert_tuple(struct nf_conntrack_tuple
*tuple
,
53 const struct nf_conntrack_tuple
*orig
)
55 tuple
->src
.u3
.ip
= orig
->dst
.u3
.ip
;
56 tuple
->dst
.u3
.ip
= orig
->src
.u3
.ip
;
61 static int ipv4_print_tuple(struct seq_file
*s
,
62 const struct nf_conntrack_tuple
*tuple
)
64 return seq_printf(s
, "src=%pI4 dst=%pI4 ",
65 &tuple
->src
.u3
.ip
, &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
) {
118 nf_log_packet(NFPROTO_IPV4
, hooknum
, skb
, in
, out
, NULL
,
119 "nf_ct_%s: dropping packet", helper
->name
);
123 if (test_bit(IPS_SEQ_ADJUST_BIT
, &ct
->status
)) {
124 typeof(nf_nat_seq_adjust_hook
) seq_adjust
;
126 seq_adjust
= rcu_dereference(nf_nat_seq_adjust_hook
);
127 if (!seq_adjust
|| !seq_adjust(skb
, ct
, ctinfo
)) {
128 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct
), drop
);
133 /* We've seen it coming out the other side: confirm it */
134 return nf_conntrack_confirm(skb
);
137 static unsigned int ipv4_conntrack_in(unsigned int hooknum
,
139 const struct net_device
*in
,
140 const struct net_device
*out
,
141 int (*okfn
)(struct sk_buff
*))
143 return nf_conntrack_in(dev_net(in
), PF_INET
, hooknum
, skb
);
146 static unsigned int ipv4_conntrack_local(unsigned int hooknum
,
148 const struct net_device
*in
,
149 const struct net_device
*out
,
150 int (*okfn
)(struct sk_buff
*))
152 /* root is playing with raw sockets. */
153 if (skb
->len
< sizeof(struct iphdr
) ||
154 ip_hdrlen(skb
) < sizeof(struct iphdr
))
156 return nf_conntrack_in(dev_net(out
), PF_INET
, hooknum
, skb
);
159 /* Connection tracking may drop packets, but never alters them, so
160 make it the first hook. */
161 static struct nf_hook_ops ipv4_conntrack_ops
[] __read_mostly
= {
163 .hook
= ipv4_conntrack_in
,
164 .owner
= THIS_MODULE
,
166 .hooknum
= NF_INET_PRE_ROUTING
,
167 .priority
= NF_IP_PRI_CONNTRACK
,
170 .hook
= ipv4_conntrack_local
,
171 .owner
= THIS_MODULE
,
173 .hooknum
= NF_INET_LOCAL_OUT
,
174 .priority
= NF_IP_PRI_CONNTRACK
,
177 .hook
= ipv4_confirm
,
178 .owner
= THIS_MODULE
,
180 .hooknum
= NF_INET_POST_ROUTING
,
181 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
184 .hook
= ipv4_confirm
,
185 .owner
= THIS_MODULE
,
187 .hooknum
= NF_INET_LOCAL_IN
,
188 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
192 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
193 static int log_invalid_proto_min
= 0;
194 static int log_invalid_proto_max
= 255;
196 static ctl_table ip_ct_sysctl_table
[] = {
198 .procname
= "ip_conntrack_max",
199 .data
= &nf_conntrack_max
,
200 .maxlen
= sizeof(int),
202 .proc_handler
= proc_dointvec
,
205 .procname
= "ip_conntrack_count",
206 .data
= &init_net
.ct
.count
,
207 .maxlen
= sizeof(int),
209 .proc_handler
= proc_dointvec
,
212 .procname
= "ip_conntrack_buckets",
213 .data
= &nf_conntrack_htable_size
,
214 .maxlen
= sizeof(unsigned int),
216 .proc_handler
= proc_dointvec
,
219 .procname
= "ip_conntrack_checksum",
220 .data
= &init_net
.ct
.sysctl_checksum
,
221 .maxlen
= sizeof(int),
223 .proc_handler
= proc_dointvec
,
226 .procname
= "ip_conntrack_log_invalid",
227 .data
= &init_net
.ct
.sysctl_log_invalid
,
228 .maxlen
= sizeof(unsigned int),
230 .proc_handler
= proc_dointvec_minmax
,
231 .extra1
= &log_invalid_proto_min
,
232 .extra2
= &log_invalid_proto_max
,
236 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
238 /* Fast function for those who don't want to parse /proc (and I don't
240 /* Reversing the socket's dst/src point of view gives us the reply
243 getorigdst(struct sock
*sk
, int optval
, void __user
*user
, int *len
)
245 const struct inet_sock
*inet
= inet_sk(sk
);
246 const struct nf_conntrack_tuple_hash
*h
;
247 struct nf_conntrack_tuple tuple
;
249 memset(&tuple
, 0, sizeof(tuple
));
250 tuple
.src
.u3
.ip
= inet
->rcv_saddr
;
251 tuple
.src
.u
.tcp
.port
= inet
->sport
;
252 tuple
.dst
.u3
.ip
= inet
->daddr
;
253 tuple
.dst
.u
.tcp
.port
= inet
->dport
;
254 tuple
.src
.l3num
= PF_INET
;
255 tuple
.dst
.protonum
= sk
->sk_protocol
;
257 /* We only do TCP and SCTP at the moment: is there a better way? */
258 if (sk
->sk_protocol
!= IPPROTO_TCP
&& sk
->sk_protocol
!= IPPROTO_SCTP
) {
259 pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
263 if ((unsigned int) *len
< sizeof(struct sockaddr_in
)) {
264 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
265 *len
, sizeof(struct sockaddr_in
));
269 h
= nf_conntrack_find_get(sock_net(sk
), &tuple
);
271 struct sockaddr_in sin
;
272 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
274 sin
.sin_family
= AF_INET
;
275 sin
.sin_port
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
276 .tuple
.dst
.u
.tcp
.port
;
277 sin
.sin_addr
.s_addr
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
279 memset(sin
.sin_zero
, 0, sizeof(sin
.sin_zero
));
281 pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
282 &sin
.sin_addr
.s_addr
, ntohs(sin
.sin_port
));
284 if (copy_to_user(user
, &sin
, sizeof(sin
)) != 0)
289 pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
290 &tuple
.src
.u3
.ip
, ntohs(tuple
.src
.u
.tcp
.port
),
291 &tuple
.dst
.u3
.ip
, ntohs(tuple
.dst
.u
.tcp
.port
));
295 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
297 #include <linux/netfilter/nfnetlink.h>
298 #include <linux/netfilter/nfnetlink_conntrack.h>
300 static int ipv4_tuple_to_nlattr(struct sk_buff
*skb
,
301 const struct nf_conntrack_tuple
*tuple
)
303 NLA_PUT_BE32(skb
, CTA_IP_V4_SRC
, tuple
->src
.u3
.ip
);
304 NLA_PUT_BE32(skb
, CTA_IP_V4_DST
, tuple
->dst
.u3
.ip
);
311 static const struct nla_policy ipv4_nla_policy
[CTA_IP_MAX
+1] = {
312 [CTA_IP_V4_SRC
] = { .type
= NLA_U32
},
313 [CTA_IP_V4_DST
] = { .type
= NLA_U32
},
316 static int ipv4_nlattr_to_tuple(struct nlattr
*tb
[],
317 struct nf_conntrack_tuple
*t
)
319 if (!tb
[CTA_IP_V4_SRC
] || !tb
[CTA_IP_V4_DST
])
322 t
->src
.u3
.ip
= nla_get_be32(tb
[CTA_IP_V4_SRC
]);
323 t
->dst
.u3
.ip
= nla_get_be32(tb
[CTA_IP_V4_DST
]);
328 static int ipv4_nlattr_tuple_size(void)
330 return nla_policy_len(ipv4_nla_policy
, CTA_IP_MAX
+ 1);
334 static struct nf_sockopt_ops so_getorigdst
= {
336 .get_optmin
= SO_ORIGINAL_DST
,
337 .get_optmax
= SO_ORIGINAL_DST
+1,
339 .owner
= THIS_MODULE
,
342 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly
= {
345 .pkt_to_tuple
= ipv4_pkt_to_tuple
,
346 .invert_tuple
= ipv4_invert_tuple
,
347 .print_tuple
= ipv4_print_tuple
,
348 .get_l4proto
= ipv4_get_l4proto
,
349 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
350 .tuple_to_nlattr
= ipv4_tuple_to_nlattr
,
351 .nlattr_tuple_size
= ipv4_nlattr_tuple_size
,
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
);