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>
26 #include <net/netfilter/nf_nat_helper.h>
28 int (*nf_nat_seq_adjust_hook
)(struct sk_buff
*skb
,
30 enum ip_conntrack_info ctinfo
);
31 EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook
);
33 static bool ipv4_pkt_to_tuple(const struct sk_buff
*skb
, unsigned int nhoff
,
34 struct nf_conntrack_tuple
*tuple
)
38 ap
= skb_header_pointer(skb
, nhoff
+ offsetof(struct iphdr
, saddr
),
39 sizeof(u_int32_t
) * 2, _addrs
);
43 tuple
->src
.u3
.ip
= ap
[0];
44 tuple
->dst
.u3
.ip
= ap
[1];
49 static bool ipv4_invert_tuple(struct nf_conntrack_tuple
*tuple
,
50 const struct nf_conntrack_tuple
*orig
)
52 tuple
->src
.u3
.ip
= orig
->dst
.u3
.ip
;
53 tuple
->dst
.u3
.ip
= orig
->src
.u3
.ip
;
58 static int ipv4_print_tuple(struct seq_file
*s
,
59 const struct nf_conntrack_tuple
*tuple
)
61 return seq_printf(s
, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
62 NIPQUAD(tuple
->src
.u3
.ip
),
63 NIPQUAD(tuple
->dst
.u3
.ip
));
66 /* Returns new sk_buff, or NULL */
67 static int nf_ct_ipv4_gather_frags(struct sk_buff
*skb
, u_int32_t user
)
74 err
= ip_defrag(skb
, user
);
78 ip_send_check(ip_hdr(skb
));
83 static int ipv4_get_l4proto(const struct sk_buff
*skb
, unsigned int nhoff
,
84 unsigned int *dataoff
, u_int8_t
*protonum
)
86 const struct iphdr
*iph
;
89 iph
= skb_header_pointer(skb
, nhoff
, sizeof(_iph
), &_iph
);
93 /* Conntrack defragments packets, we might still see fragments
94 * inside ICMP packets though. */
95 if (iph
->frag_off
& htons(IP_OFFSET
))
98 *dataoff
= nhoff
+ (iph
->ihl
<< 2);
99 *protonum
= iph
->protocol
;
104 static unsigned int ipv4_confirm(unsigned int hooknum
,
106 const struct net_device
*in
,
107 const struct net_device
*out
,
108 int (*okfn
)(struct sk_buff
*))
111 enum ip_conntrack_info ctinfo
;
112 const struct nf_conn_help
*help
;
113 const struct nf_conntrack_helper
*helper
;
116 /* This is where we call the helper: as the packet goes out. */
117 ct
= nf_ct_get(skb
, &ctinfo
);
118 if (!ct
|| ctinfo
== IP_CT_RELATED
+ IP_CT_IS_REPLY
)
121 help
= nfct_help(ct
);
125 /* rcu_read_lock()ed by nf_hook_slow */
126 helper
= rcu_dereference(help
->helper
);
130 ret
= helper
->help(skb
, skb_network_offset(skb
) + ip_hdrlen(skb
),
132 if (ret
!= NF_ACCEPT
)
135 if (test_bit(IPS_SEQ_ADJUST_BIT
, &ct
->status
)) {
136 typeof(nf_nat_seq_adjust_hook
) seq_adjust
;
138 seq_adjust
= rcu_dereference(nf_nat_seq_adjust_hook
);
139 if (!seq_adjust
|| !seq_adjust(skb
, ct
, ctinfo
))
143 /* We've seen it coming out the other side: confirm it */
144 return nf_conntrack_confirm(skb
);
147 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum
,
149 const struct net_device
*in
,
150 const struct net_device
*out
,
151 int (*okfn
)(struct sk_buff
*))
153 /* Previously seen (loopback)? Ignore. Do this before
158 /* Gather fragments. */
159 if (ip_hdr(skb
)->frag_off
& htons(IP_MF
| IP_OFFSET
)) {
160 if (nf_ct_ipv4_gather_frags(skb
,
161 hooknum
== NF_INET_PRE_ROUTING
?
162 IP_DEFRAG_CONNTRACK_IN
:
163 IP_DEFRAG_CONNTRACK_OUT
))
169 static unsigned int ipv4_conntrack_in(unsigned int hooknum
,
171 const struct net_device
*in
,
172 const struct net_device
*out
,
173 int (*okfn
)(struct sk_buff
*))
175 return nf_conntrack_in(dev_net(in
), PF_INET
, hooknum
, skb
);
178 static unsigned int ipv4_conntrack_local(unsigned int hooknum
,
180 const struct net_device
*in
,
181 const struct net_device
*out
,
182 int (*okfn
)(struct sk_buff
*))
184 /* root is playing with raw sockets. */
185 if (skb
->len
< sizeof(struct iphdr
) ||
186 ip_hdrlen(skb
) < sizeof(struct iphdr
)) {
188 printk("ipt_hook: happy cracking.\n");
191 return nf_conntrack_in(dev_net(out
), PF_INET
, hooknum
, skb
);
194 /* Connection tracking may drop packets, but never alters them, so
195 make it the first hook. */
196 static struct nf_hook_ops ipv4_conntrack_ops
[] __read_mostly
= {
198 .hook
= ipv4_conntrack_defrag
,
199 .owner
= THIS_MODULE
,
201 .hooknum
= NF_INET_PRE_ROUTING
,
202 .priority
= NF_IP_PRI_CONNTRACK_DEFRAG
,
205 .hook
= ipv4_conntrack_in
,
206 .owner
= THIS_MODULE
,
208 .hooknum
= NF_INET_PRE_ROUTING
,
209 .priority
= NF_IP_PRI_CONNTRACK
,
212 .hook
= ipv4_conntrack_defrag
,
213 .owner
= THIS_MODULE
,
215 .hooknum
= NF_INET_LOCAL_OUT
,
216 .priority
= NF_IP_PRI_CONNTRACK_DEFRAG
,
219 .hook
= ipv4_conntrack_local
,
220 .owner
= THIS_MODULE
,
222 .hooknum
= NF_INET_LOCAL_OUT
,
223 .priority
= NF_IP_PRI_CONNTRACK
,
226 .hook
= ipv4_confirm
,
227 .owner
= THIS_MODULE
,
229 .hooknum
= NF_INET_POST_ROUTING
,
230 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
233 .hook
= ipv4_confirm
,
234 .owner
= THIS_MODULE
,
236 .hooknum
= NF_INET_LOCAL_IN
,
237 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
241 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
242 static int log_invalid_proto_min
= 0;
243 static int log_invalid_proto_max
= 255;
245 static ctl_table ip_ct_sysctl_table
[] = {
247 .ctl_name
= NET_IPV4_NF_CONNTRACK_MAX
,
248 .procname
= "ip_conntrack_max",
249 .data
= &nf_conntrack_max
,
250 .maxlen
= sizeof(int),
252 .proc_handler
= &proc_dointvec
,
255 .ctl_name
= NET_IPV4_NF_CONNTRACK_COUNT
,
256 .procname
= "ip_conntrack_count",
257 .data
= &init_net
.ct
.count
,
258 .maxlen
= sizeof(int),
260 .proc_handler
= &proc_dointvec
,
263 .ctl_name
= NET_IPV4_NF_CONNTRACK_BUCKETS
,
264 .procname
= "ip_conntrack_buckets",
265 .data
= &nf_conntrack_htable_size
,
266 .maxlen
= sizeof(unsigned int),
268 .proc_handler
= &proc_dointvec
,
271 .ctl_name
= NET_IPV4_NF_CONNTRACK_CHECKSUM
,
272 .procname
= "ip_conntrack_checksum",
273 .data
= &nf_conntrack_checksum
,
274 .maxlen
= sizeof(int),
276 .proc_handler
= &proc_dointvec
,
279 .ctl_name
= NET_IPV4_NF_CONNTRACK_LOG_INVALID
,
280 .procname
= "ip_conntrack_log_invalid",
281 .data
= &nf_ct_log_invalid
,
282 .maxlen
= sizeof(unsigned int),
284 .proc_handler
= &proc_dointvec_minmax
,
285 .strategy
= &sysctl_intvec
,
286 .extra1
= &log_invalid_proto_min
,
287 .extra2
= &log_invalid_proto_max
,
293 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
295 /* Fast function for those who don't want to parse /proc (and I don't
297 /* Reversing the socket's dst/src point of view gives us the reply
300 getorigdst(struct sock
*sk
, int optval
, void __user
*user
, int *len
)
302 const struct inet_sock
*inet
= inet_sk(sk
);
303 const struct nf_conntrack_tuple_hash
*h
;
304 struct nf_conntrack_tuple tuple
;
306 memset(&tuple
, 0, sizeof(tuple
));
307 tuple
.src
.u3
.ip
= inet
->rcv_saddr
;
308 tuple
.src
.u
.tcp
.port
= inet
->sport
;
309 tuple
.dst
.u3
.ip
= inet
->daddr
;
310 tuple
.dst
.u
.tcp
.port
= inet
->dport
;
311 tuple
.src
.l3num
= PF_INET
;
312 tuple
.dst
.protonum
= IPPROTO_TCP
;
314 /* We only do TCP at the moment: is there a better way? */
315 if (strcmp(sk
->sk_prot
->name
, "TCP")) {
316 pr_debug("SO_ORIGINAL_DST: Not a TCP socket\n");
320 if ((unsigned int) *len
< sizeof(struct sockaddr_in
)) {
321 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
322 *len
, sizeof(struct sockaddr_in
));
326 h
= nf_conntrack_find_get(sock_net(sk
), &tuple
);
328 struct sockaddr_in sin
;
329 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
331 sin
.sin_family
= AF_INET
;
332 sin
.sin_port
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
333 .tuple
.dst
.u
.tcp
.port
;
334 sin
.sin_addr
.s_addr
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
336 memset(sin
.sin_zero
, 0, sizeof(sin
.sin_zero
));
338 pr_debug("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
339 NIPQUAD(sin
.sin_addr
.s_addr
), ntohs(sin
.sin_port
));
341 if (copy_to_user(user
, &sin
, sizeof(sin
)) != 0)
346 pr_debug("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
347 NIPQUAD(tuple
.src
.u3
.ip
), ntohs(tuple
.src
.u
.tcp
.port
),
348 NIPQUAD(tuple
.dst
.u3
.ip
), ntohs(tuple
.dst
.u
.tcp
.port
));
352 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
354 #include <linux/netfilter/nfnetlink.h>
355 #include <linux/netfilter/nfnetlink_conntrack.h>
357 static int ipv4_tuple_to_nlattr(struct sk_buff
*skb
,
358 const struct nf_conntrack_tuple
*tuple
)
360 NLA_PUT_BE32(skb
, CTA_IP_V4_SRC
, tuple
->src
.u3
.ip
);
361 NLA_PUT_BE32(skb
, CTA_IP_V4_DST
, tuple
->dst
.u3
.ip
);
368 static const struct nla_policy ipv4_nla_policy
[CTA_IP_MAX
+1] = {
369 [CTA_IP_V4_SRC
] = { .type
= NLA_U32
},
370 [CTA_IP_V4_DST
] = { .type
= NLA_U32
},
373 static int ipv4_nlattr_to_tuple(struct nlattr
*tb
[],
374 struct nf_conntrack_tuple
*t
)
376 if (!tb
[CTA_IP_V4_SRC
] || !tb
[CTA_IP_V4_DST
])
379 t
->src
.u3
.ip
= nla_get_be32(tb
[CTA_IP_V4_SRC
]);
380 t
->dst
.u3
.ip
= nla_get_be32(tb
[CTA_IP_V4_DST
]);
386 static struct nf_sockopt_ops so_getorigdst
= {
388 .get_optmin
= SO_ORIGINAL_DST
,
389 .get_optmax
= SO_ORIGINAL_DST
+1,
391 .owner
= THIS_MODULE
,
394 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly
= {
397 .pkt_to_tuple
= ipv4_pkt_to_tuple
,
398 .invert_tuple
= ipv4_invert_tuple
,
399 .print_tuple
= ipv4_print_tuple
,
400 .get_l4proto
= ipv4_get_l4proto
,
401 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
402 .tuple_to_nlattr
= ipv4_tuple_to_nlattr
,
403 .nlattr_to_tuple
= ipv4_nlattr_to_tuple
,
404 .nla_policy
= ipv4_nla_policy
,
406 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
407 .ctl_table_path
= nf_net_ipv4_netfilter_sysctl_path
,
408 .ctl_table
= ip_ct_sysctl_table
,
413 module_param_call(hashsize
, nf_conntrack_set_hashsize
, param_get_uint
,
414 &nf_conntrack_htable_size
, 0600);
416 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET
));
417 MODULE_ALIAS("ip_conntrack");
418 MODULE_LICENSE("GPL");
420 static int __init
nf_conntrack_l3proto_ipv4_init(void)
426 ret
= nf_register_sockopt(&so_getorigdst
);
428 printk(KERN_ERR
"Unable to register netfilter socket option\n");
432 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4
);
434 printk("nf_conntrack_ipv4: can't register tcp.\n");
435 goto cleanup_sockopt
;
438 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4
);
440 printk("nf_conntrack_ipv4: can't register udp.\n");
444 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp
);
446 printk("nf_conntrack_ipv4: can't register icmp.\n");
450 ret
= nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4
);
452 printk("nf_conntrack_ipv4: can't register ipv4\n");
456 ret
= nf_register_hooks(ipv4_conntrack_ops
,
457 ARRAY_SIZE(ipv4_conntrack_ops
));
459 printk("nf_conntrack_ipv4: can't register hooks.\n");
462 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
463 ret
= nf_conntrack_ipv4_compat_init();
468 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
470 nf_unregister_hooks(ipv4_conntrack_ops
, ARRAY_SIZE(ipv4_conntrack_ops
));
473 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
475 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp
);
477 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4
);
479 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4
);
481 nf_unregister_sockopt(&so_getorigdst
);
485 static void __exit
nf_conntrack_l3proto_ipv4_fini(void)
488 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
489 nf_conntrack_ipv4_compat_fini();
491 nf_unregister_hooks(ipv4_conntrack_ops
, ARRAY_SIZE(ipv4_conntrack_ops
));
492 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
493 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp
);
494 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4
);
495 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4
);
496 nf_unregister_sockopt(&so_getorigdst
);
499 module_init(nf_conntrack_l3proto_ipv4_init
);
500 module_exit(nf_conntrack_l3proto_ipv4_fini
);
502 void need_ipv4_conntrack(void)
506 EXPORT_SYMBOL_GPL(need_ipv4_conntrack
);