2 /* (C) 1999-2001 Paul `Rusty' Russell
3 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
4 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/types.h>
13 #include <linux/netfilter.h>
14 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/icmp.h>
17 #include <linux/sysctl.h>
18 #include <net/route.h>
21 #include <linux/netfilter_ipv4.h>
22 #include <net/netfilter/nf_conntrack.h>
23 #include <net/netfilter/nf_conntrack_helper.h>
24 #include <net/netfilter/nf_conntrack_l4proto.h>
25 #include <net/netfilter/nf_conntrack_l3proto.h>
26 #include <net/netfilter/nf_conntrack_zones.h>
27 #include <net/netfilter/nf_conntrack_core.h>
28 #include <net/netfilter/nf_conntrack_seqadj.h>
29 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
30 #include <net/netfilter/nf_nat_helper.h>
31 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
32 #include <net/netfilter/nf_log.h>
34 static int conntrack4_net_id __read_mostly
;
35 static DEFINE_MUTEX(register_ipv4_hooks
);
37 struct conntrack4_net
{
41 static bool ipv4_pkt_to_tuple(const struct sk_buff
*skb
, unsigned int nhoff
,
42 struct nf_conntrack_tuple
*tuple
)
46 ap
= skb_header_pointer(skb
, nhoff
+ offsetof(struct iphdr
, saddr
),
47 sizeof(u_int32_t
) * 2, _addrs
);
51 tuple
->src
.u3
.ip
= ap
[0];
52 tuple
->dst
.u3
.ip
= ap
[1];
57 static bool ipv4_invert_tuple(struct nf_conntrack_tuple
*tuple
,
58 const struct nf_conntrack_tuple
*orig
)
60 tuple
->src
.u3
.ip
= orig
->dst
.u3
.ip
;
61 tuple
->dst
.u3
.ip
= orig
->src
.u3
.ip
;
66 static void ipv4_print_tuple(struct seq_file
*s
,
67 const struct nf_conntrack_tuple
*tuple
)
69 seq_printf(s
, "src=%pI4 dst=%pI4 ",
70 &tuple
->src
.u3
.ip
, &tuple
->dst
.u3
.ip
);
73 static int ipv4_get_l4proto(const struct sk_buff
*skb
, unsigned int nhoff
,
74 unsigned int *dataoff
, u_int8_t
*protonum
)
76 const struct iphdr
*iph
;
79 iph
= skb_header_pointer(skb
, nhoff
, sizeof(_iph
), &_iph
);
83 /* Conntrack defragments packets, we might still see fragments
84 * inside ICMP packets though. */
85 if (iph
->frag_off
& htons(IP_OFFSET
))
88 *dataoff
= nhoff
+ (iph
->ihl
<< 2);
89 *protonum
= iph
->protocol
;
91 /* Check bogus IP headers */
92 if (*dataoff
> skb
->len
) {
93 pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: "
94 "nhoff %u, ihl %u, skblen %u\n",
95 nhoff
, iph
->ihl
<< 2, skb
->len
);
102 static unsigned int ipv4_helper(void *priv
,
104 const struct nf_hook_state
*state
)
107 enum ip_conntrack_info ctinfo
;
108 const struct nf_conn_help
*help
;
109 const struct nf_conntrack_helper
*helper
;
111 /* This is where we call the helper: as the packet goes out. */
112 ct
= nf_ct_get(skb
, &ctinfo
);
113 if (!ct
|| ctinfo
== IP_CT_RELATED_REPLY
)
116 help
= nfct_help(ct
);
120 /* rcu_read_lock()ed by nf_hook_thresh */
121 helper
= rcu_dereference(help
->helper
);
125 return helper
->help(skb
, skb_network_offset(skb
) + ip_hdrlen(skb
),
129 static unsigned int ipv4_confirm(void *priv
,
131 const struct nf_hook_state
*state
)
134 enum ip_conntrack_info ctinfo
;
136 ct
= nf_ct_get(skb
, &ctinfo
);
137 if (!ct
|| ctinfo
== IP_CT_RELATED_REPLY
)
140 /* adjust seqs for loopback traffic only in outgoing direction */
141 if (test_bit(IPS_SEQ_ADJUST_BIT
, &ct
->status
) &&
142 !nf_is_loopback_packet(skb
)) {
143 if (!nf_ct_seq_adjust(skb
, ct
, ctinfo
, ip_hdrlen(skb
))) {
144 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct
), drop
);
149 /* We've seen it coming out the other side: confirm it */
150 return nf_conntrack_confirm(skb
);
153 static unsigned int ipv4_conntrack_in(void *priv
,
155 const struct nf_hook_state
*state
)
157 return nf_conntrack_in(state
->net
, PF_INET
, state
->hook
, skb
);
160 static unsigned int ipv4_conntrack_local(void *priv
,
162 const struct nf_hook_state
*state
)
164 /* root is playing with raw sockets. */
165 if (skb
->len
< sizeof(struct iphdr
) ||
166 ip_hdrlen(skb
) < sizeof(struct iphdr
))
168 return nf_conntrack_in(state
->net
, PF_INET
, state
->hook
, skb
);
171 /* Connection tracking may drop packets, but never alters them, so
172 make it the first hook. */
173 static struct nf_hook_ops ipv4_conntrack_ops
[] __read_mostly
= {
175 .hook
= ipv4_conntrack_in
,
177 .hooknum
= NF_INET_PRE_ROUTING
,
178 .priority
= NF_IP_PRI_CONNTRACK
,
181 .hook
= ipv4_conntrack_local
,
183 .hooknum
= NF_INET_LOCAL_OUT
,
184 .priority
= NF_IP_PRI_CONNTRACK
,
189 .hooknum
= NF_INET_POST_ROUTING
,
190 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
193 .hook
= ipv4_confirm
,
195 .hooknum
= NF_INET_POST_ROUTING
,
196 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
201 .hooknum
= NF_INET_LOCAL_IN
,
202 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
205 .hook
= ipv4_confirm
,
207 .hooknum
= NF_INET_LOCAL_IN
,
208 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
212 /* Fast function for those who don't want to parse /proc (and I don't
214 /* Reversing the socket's dst/src point of view gives us the reply
217 getorigdst(struct sock
*sk
, int optval
, void __user
*user
, int *len
)
219 const struct inet_sock
*inet
= inet_sk(sk
);
220 const struct nf_conntrack_tuple_hash
*h
;
221 struct nf_conntrack_tuple tuple
;
223 memset(&tuple
, 0, sizeof(tuple
));
224 tuple
.src
.u3
.ip
= inet
->inet_rcv_saddr
;
225 tuple
.src
.u
.tcp
.port
= inet
->inet_sport
;
226 tuple
.dst
.u3
.ip
= inet
->inet_daddr
;
227 tuple
.dst
.u
.tcp
.port
= inet
->inet_dport
;
228 tuple
.src
.l3num
= PF_INET
;
229 tuple
.dst
.protonum
= sk
->sk_protocol
;
231 /* We only do TCP and SCTP at the moment: is there a better way? */
232 if (sk
->sk_protocol
!= IPPROTO_TCP
&& sk
->sk_protocol
!= IPPROTO_SCTP
) {
233 pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
237 if ((unsigned int) *len
< sizeof(struct sockaddr_in
)) {
238 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
239 *len
, sizeof(struct sockaddr_in
));
243 h
= nf_conntrack_find_get(sock_net(sk
), &nf_ct_zone_dflt
, &tuple
);
245 struct sockaddr_in sin
;
246 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
248 sin
.sin_family
= AF_INET
;
249 sin
.sin_port
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
250 .tuple
.dst
.u
.tcp
.port
;
251 sin
.sin_addr
.s_addr
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
253 memset(sin
.sin_zero
, 0, sizeof(sin
.sin_zero
));
255 pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
256 &sin
.sin_addr
.s_addr
, ntohs(sin
.sin_port
));
258 if (copy_to_user(user
, &sin
, sizeof(sin
)) != 0)
263 pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
264 &tuple
.src
.u3
.ip
, ntohs(tuple
.src
.u
.tcp
.port
),
265 &tuple
.dst
.u3
.ip
, ntohs(tuple
.dst
.u
.tcp
.port
));
269 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
271 #include <linux/netfilter/nfnetlink.h>
272 #include <linux/netfilter/nfnetlink_conntrack.h>
274 static int ipv4_tuple_to_nlattr(struct sk_buff
*skb
,
275 const struct nf_conntrack_tuple
*tuple
)
277 if (nla_put_in_addr(skb
, CTA_IP_V4_SRC
, tuple
->src
.u3
.ip
) ||
278 nla_put_in_addr(skb
, CTA_IP_V4_DST
, tuple
->dst
.u3
.ip
))
279 goto nla_put_failure
;
286 static const struct nla_policy ipv4_nla_policy
[CTA_IP_MAX
+1] = {
287 [CTA_IP_V4_SRC
] = { .type
= NLA_U32
},
288 [CTA_IP_V4_DST
] = { .type
= NLA_U32
},
291 static int ipv4_nlattr_to_tuple(struct nlattr
*tb
[],
292 struct nf_conntrack_tuple
*t
)
294 if (!tb
[CTA_IP_V4_SRC
] || !tb
[CTA_IP_V4_DST
])
297 t
->src
.u3
.ip
= nla_get_in_addr(tb
[CTA_IP_V4_SRC
]);
298 t
->dst
.u3
.ip
= nla_get_in_addr(tb
[CTA_IP_V4_DST
]);
303 static int ipv4_nlattr_tuple_size(void)
305 return nla_policy_len(ipv4_nla_policy
, CTA_IP_MAX
+ 1);
309 static struct nf_sockopt_ops so_getorigdst
= {
311 .get_optmin
= SO_ORIGINAL_DST
,
312 .get_optmax
= SO_ORIGINAL_DST
+1,
314 .owner
= THIS_MODULE
,
317 static int ipv4_hooks_register(struct net
*net
)
319 struct conntrack4_net
*cnet
= net_generic(net
, conntrack4_net_id
);
322 mutex_lock(®ister_ipv4_hooks
);
328 err
= nf_defrag_ipv4_enable(net
);
334 err
= nf_register_net_hooks(net
, ipv4_conntrack_ops
,
335 ARRAY_SIZE(ipv4_conntrack_ops
));
340 mutex_unlock(®ister_ipv4_hooks
);
344 static void ipv4_hooks_unregister(struct net
*net
)
346 struct conntrack4_net
*cnet
= net_generic(net
, conntrack4_net_id
);
348 mutex_lock(®ister_ipv4_hooks
);
349 if (cnet
->users
&& (--cnet
->users
== 0))
350 nf_unregister_net_hooks(net
, ipv4_conntrack_ops
,
351 ARRAY_SIZE(ipv4_conntrack_ops
));
352 mutex_unlock(®ister_ipv4_hooks
);
355 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly
= {
358 .pkt_to_tuple
= ipv4_pkt_to_tuple
,
359 .invert_tuple
= ipv4_invert_tuple
,
360 .print_tuple
= ipv4_print_tuple
,
361 .get_l4proto
= ipv4_get_l4proto
,
362 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
363 .tuple_to_nlattr
= ipv4_tuple_to_nlattr
,
364 .nlattr_tuple_size
= ipv4_nlattr_tuple_size
,
365 .nlattr_to_tuple
= ipv4_nlattr_to_tuple
,
366 .nla_policy
= ipv4_nla_policy
,
368 .net_ns_get
= ipv4_hooks_register
,
369 .net_ns_put
= ipv4_hooks_unregister
,
373 module_param_call(hashsize
, nf_conntrack_set_hashsize
, param_get_uint
,
374 &nf_conntrack_htable_size
, 0600);
376 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET
));
377 MODULE_ALIAS("ip_conntrack");
378 MODULE_LICENSE("GPL");
380 static struct nf_conntrack_l4proto
*builtin_l4proto4
[] = {
381 &nf_conntrack_l4proto_tcp4
,
382 &nf_conntrack_l4proto_udp4
,
383 &nf_conntrack_l4proto_icmp
,
384 #ifdef CONFIG_NF_CT_PROTO_DCCP
385 &nf_conntrack_l4proto_dccp4
,
387 #ifdef CONFIG_NF_CT_PROTO_SCTP
388 &nf_conntrack_l4proto_sctp4
,
390 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
391 &nf_conntrack_l4proto_udplite4
,
395 static int ipv4_net_init(struct net
*net
)
399 ret
= nf_ct_l4proto_pernet_register(net
, builtin_l4proto4
,
400 ARRAY_SIZE(builtin_l4proto4
));
403 ret
= nf_ct_l3proto_pernet_register(net
, &nf_conntrack_l3proto_ipv4
);
405 pr_err("nf_conntrack_ipv4: pernet registration failed\n");
406 nf_ct_l4proto_pernet_unregister(net
, builtin_l4proto4
,
407 ARRAY_SIZE(builtin_l4proto4
));
412 static void ipv4_net_exit(struct net
*net
)
414 nf_ct_l3proto_pernet_unregister(net
, &nf_conntrack_l3proto_ipv4
);
415 nf_ct_l4proto_pernet_unregister(net
, builtin_l4proto4
,
416 ARRAY_SIZE(builtin_l4proto4
));
419 static struct pernet_operations ipv4_net_ops
= {
420 .init
= ipv4_net_init
,
421 .exit
= ipv4_net_exit
,
422 .id
= &conntrack4_net_id
,
423 .size
= sizeof(struct conntrack4_net
),
426 static int __init
nf_conntrack_l3proto_ipv4_init(void)
432 ret
= nf_register_sockopt(&so_getorigdst
);
434 pr_err("Unable to register netfilter socket option\n");
438 ret
= register_pernet_subsys(&ipv4_net_ops
);
440 pr_err("nf_conntrack_ipv4: can't register pernet ops\n");
441 goto cleanup_sockopt
;
444 ret
= nf_ct_l4proto_register(builtin_l4proto4
,
445 ARRAY_SIZE(builtin_l4proto4
));
449 ret
= nf_ct_l3proto_register(&nf_conntrack_l3proto_ipv4
);
451 pr_err("nf_conntrack_ipv4: can't register ipv4 proto.\n");
452 goto cleanup_l4proto
;
457 nf_ct_l4proto_unregister(builtin_l4proto4
,
458 ARRAY_SIZE(builtin_l4proto4
));
460 unregister_pernet_subsys(&ipv4_net_ops
);
462 nf_unregister_sockopt(&so_getorigdst
);
466 static void __exit
nf_conntrack_l3proto_ipv4_fini(void)
469 nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
470 nf_ct_l4proto_unregister(builtin_l4proto4
,
471 ARRAY_SIZE(builtin_l4proto4
));
472 unregister_pernet_subsys(&ipv4_net_ops
);
473 nf_unregister_sockopt(&so_getorigdst
);
476 module_init(nf_conntrack_l3proto_ipv4_init
);
477 module_exit(nf_conntrack_l3proto_ipv4_fini
);