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 int ipv4_get_l4proto(const struct sk_buff
*skb
, unsigned int nhoff
,
67 unsigned int *dataoff
, u_int8_t
*protonum
)
69 const struct iphdr
*iph
;
72 iph
= skb_header_pointer(skb
, nhoff
, sizeof(_iph
), &_iph
);
76 /* Conntrack defragments packets, we might still see fragments
77 * inside ICMP packets though. */
78 if (iph
->frag_off
& htons(IP_OFFSET
))
81 *dataoff
= nhoff
+ (iph
->ihl
<< 2);
82 *protonum
= iph
->protocol
;
84 /* Check bogus IP headers */
85 if (*dataoff
> skb
->len
) {
86 pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: "
87 "nhoff %u, ihl %u, skblen %u\n",
88 nhoff
, iph
->ihl
<< 2, skb
->len
);
95 static unsigned int ipv4_helper(void *priv
,
97 const struct nf_hook_state
*state
)
100 enum ip_conntrack_info ctinfo
;
101 const struct nf_conn_help
*help
;
102 const struct nf_conntrack_helper
*helper
;
104 /* This is where we call the helper: as the packet goes out. */
105 ct
= nf_ct_get(skb
, &ctinfo
);
106 if (!ct
|| ctinfo
== IP_CT_RELATED_REPLY
)
109 help
= nfct_help(ct
);
113 /* rcu_read_lock()ed by nf_hook_thresh */
114 helper
= rcu_dereference(help
->helper
);
118 return helper
->help(skb
, skb_network_offset(skb
) + ip_hdrlen(skb
),
122 static unsigned int ipv4_confirm(void *priv
,
124 const struct nf_hook_state
*state
)
127 enum ip_conntrack_info ctinfo
;
129 ct
= nf_ct_get(skb
, &ctinfo
);
130 if (!ct
|| ctinfo
== IP_CT_RELATED_REPLY
)
133 /* adjust seqs for loopback traffic only in outgoing direction */
134 if (test_bit(IPS_SEQ_ADJUST_BIT
, &ct
->status
) &&
135 !nf_is_loopback_packet(skb
)) {
136 if (!nf_ct_seq_adjust(skb
, ct
, ctinfo
, ip_hdrlen(skb
))) {
137 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct
), drop
);
142 /* We've seen it coming out the other side: confirm it */
143 return nf_conntrack_confirm(skb
);
146 static unsigned int ipv4_conntrack_in(void *priv
,
148 const struct nf_hook_state
*state
)
150 return nf_conntrack_in(state
->net
, PF_INET
, state
->hook
, skb
);
153 static unsigned int ipv4_conntrack_local(void *priv
,
155 const struct nf_hook_state
*state
)
157 /* root is playing with raw sockets. */
158 if (skb
->len
< sizeof(struct iphdr
) ||
159 ip_hdrlen(skb
) < sizeof(struct iphdr
))
162 if (ip_is_fragment(ip_hdr(skb
))) { /* IP_NODEFRAG setsockopt set */
163 enum ip_conntrack_info ctinfo
;
164 struct nf_conn
*tmpl
;
166 tmpl
= nf_ct_get(skb
, &ctinfo
);
167 if (tmpl
&& nf_ct_is_template(tmpl
)) {
168 /* when skipping ct, clear templates to avoid fooling
169 * later targets/matches
177 return nf_conntrack_in(state
->net
, PF_INET
, state
->hook
, skb
);
180 /* Connection tracking may drop packets, but never alters them, so
181 make it the first hook. */
182 static const struct nf_hook_ops ipv4_conntrack_ops
[] = {
184 .hook
= ipv4_conntrack_in
,
186 .hooknum
= NF_INET_PRE_ROUTING
,
187 .priority
= NF_IP_PRI_CONNTRACK
,
190 .hook
= ipv4_conntrack_local
,
192 .hooknum
= NF_INET_LOCAL_OUT
,
193 .priority
= NF_IP_PRI_CONNTRACK
,
198 .hooknum
= NF_INET_POST_ROUTING
,
199 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
202 .hook
= ipv4_confirm
,
204 .hooknum
= NF_INET_POST_ROUTING
,
205 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
210 .hooknum
= NF_INET_LOCAL_IN
,
211 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
214 .hook
= ipv4_confirm
,
216 .hooknum
= NF_INET_LOCAL_IN
,
217 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
221 /* Fast function for those who don't want to parse /proc (and I don't
223 /* Reversing the socket's dst/src point of view gives us the reply
226 getorigdst(struct sock
*sk
, int optval
, void __user
*user
, int *len
)
228 const struct inet_sock
*inet
= inet_sk(sk
);
229 const struct nf_conntrack_tuple_hash
*h
;
230 struct nf_conntrack_tuple tuple
;
232 memset(&tuple
, 0, sizeof(tuple
));
235 tuple
.src
.u3
.ip
= inet
->inet_rcv_saddr
;
236 tuple
.src
.u
.tcp
.port
= inet
->inet_sport
;
237 tuple
.dst
.u3
.ip
= inet
->inet_daddr
;
238 tuple
.dst
.u
.tcp
.port
= inet
->inet_dport
;
239 tuple
.src
.l3num
= PF_INET
;
240 tuple
.dst
.protonum
= sk
->sk_protocol
;
243 /* We only do TCP and SCTP at the moment: is there a better way? */
244 if (tuple
.dst
.protonum
!= IPPROTO_TCP
&&
245 tuple
.dst
.protonum
!= IPPROTO_SCTP
) {
246 pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
250 if ((unsigned int) *len
< sizeof(struct sockaddr_in
)) {
251 pr_debug("SO_ORIGINAL_DST: len %d not %zu\n",
252 *len
, sizeof(struct sockaddr_in
));
256 h
= nf_conntrack_find_get(sock_net(sk
), &nf_ct_zone_dflt
, &tuple
);
258 struct sockaddr_in sin
;
259 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
261 sin
.sin_family
= AF_INET
;
262 sin
.sin_port
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
263 .tuple
.dst
.u
.tcp
.port
;
264 sin
.sin_addr
.s_addr
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
266 memset(sin
.sin_zero
, 0, sizeof(sin
.sin_zero
));
268 pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
269 &sin
.sin_addr
.s_addr
, ntohs(sin
.sin_port
));
271 if (copy_to_user(user
, &sin
, sizeof(sin
)) != 0)
276 pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
277 &tuple
.src
.u3
.ip
, ntohs(tuple
.src
.u
.tcp
.port
),
278 &tuple
.dst
.u3
.ip
, ntohs(tuple
.dst
.u
.tcp
.port
));
282 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
284 #include <linux/netfilter/nfnetlink.h>
285 #include <linux/netfilter/nfnetlink_conntrack.h>
287 static int ipv4_tuple_to_nlattr(struct sk_buff
*skb
,
288 const struct nf_conntrack_tuple
*tuple
)
290 if (nla_put_in_addr(skb
, CTA_IP_V4_SRC
, tuple
->src
.u3
.ip
) ||
291 nla_put_in_addr(skb
, CTA_IP_V4_DST
, tuple
->dst
.u3
.ip
))
292 goto nla_put_failure
;
299 static const struct nla_policy ipv4_nla_policy
[CTA_IP_MAX
+1] = {
300 [CTA_IP_V4_SRC
] = { .type
= NLA_U32
},
301 [CTA_IP_V4_DST
] = { .type
= NLA_U32
},
304 static int ipv4_nlattr_to_tuple(struct nlattr
*tb
[],
305 struct nf_conntrack_tuple
*t
)
307 if (!tb
[CTA_IP_V4_SRC
] || !tb
[CTA_IP_V4_DST
])
310 t
->src
.u3
.ip
= nla_get_in_addr(tb
[CTA_IP_V4_SRC
]);
311 t
->dst
.u3
.ip
= nla_get_in_addr(tb
[CTA_IP_V4_DST
]);
317 static struct nf_sockopt_ops so_getorigdst
= {
319 .get_optmin
= SO_ORIGINAL_DST
,
320 .get_optmax
= SO_ORIGINAL_DST
+1,
322 .owner
= THIS_MODULE
,
325 static int ipv4_hooks_register(struct net
*net
)
327 struct conntrack4_net
*cnet
= net_generic(net
, conntrack4_net_id
);
330 mutex_lock(®ister_ipv4_hooks
);
336 err
= nf_defrag_ipv4_enable(net
);
342 err
= nf_register_net_hooks(net
, ipv4_conntrack_ops
,
343 ARRAY_SIZE(ipv4_conntrack_ops
));
348 mutex_unlock(®ister_ipv4_hooks
);
352 static void ipv4_hooks_unregister(struct net
*net
)
354 struct conntrack4_net
*cnet
= net_generic(net
, conntrack4_net_id
);
356 mutex_lock(®ister_ipv4_hooks
);
357 if (cnet
->users
&& (--cnet
->users
== 0))
358 nf_unregister_net_hooks(net
, ipv4_conntrack_ops
,
359 ARRAY_SIZE(ipv4_conntrack_ops
));
360 mutex_unlock(®ister_ipv4_hooks
);
363 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly
= {
365 .pkt_to_tuple
= ipv4_pkt_to_tuple
,
366 .invert_tuple
= ipv4_invert_tuple
,
367 .get_l4proto
= ipv4_get_l4proto
,
368 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
369 .tuple_to_nlattr
= ipv4_tuple_to_nlattr
,
370 .nlattr_to_tuple
= ipv4_nlattr_to_tuple
,
371 .nla_policy
= ipv4_nla_policy
,
372 .nla_size
= NLA_ALIGN(NLA_HDRLEN
+ sizeof(u32
)) + /* CTA_IP_V4_SRC */
373 NLA_ALIGN(NLA_HDRLEN
+ sizeof(u32
)), /* CTA_IP_V4_DST */
375 .net_ns_get
= ipv4_hooks_register
,
376 .net_ns_put
= ipv4_hooks_unregister
,
380 module_param_call(hashsize
, nf_conntrack_set_hashsize
, param_get_uint
,
381 &nf_conntrack_htable_size
, 0600);
383 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET
));
384 MODULE_ALIAS("ip_conntrack");
385 MODULE_LICENSE("GPL");
387 static struct nf_conntrack_l4proto
*builtin_l4proto4
[] = {
388 &nf_conntrack_l4proto_tcp4
,
389 &nf_conntrack_l4proto_udp4
,
390 &nf_conntrack_l4proto_icmp
,
391 #ifdef CONFIG_NF_CT_PROTO_DCCP
392 &nf_conntrack_l4proto_dccp4
,
394 #ifdef CONFIG_NF_CT_PROTO_SCTP
395 &nf_conntrack_l4proto_sctp4
,
397 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
398 &nf_conntrack_l4proto_udplite4
,
402 static int ipv4_net_init(struct net
*net
)
404 return nf_ct_l4proto_pernet_register(net
, builtin_l4proto4
,
405 ARRAY_SIZE(builtin_l4proto4
));
408 static void ipv4_net_exit(struct net
*net
)
410 nf_ct_l4proto_pernet_unregister(net
, builtin_l4proto4
,
411 ARRAY_SIZE(builtin_l4proto4
));
414 static struct pernet_operations ipv4_net_ops
= {
415 .init
= ipv4_net_init
,
416 .exit
= ipv4_net_exit
,
417 .id
= &conntrack4_net_id
,
418 .size
= sizeof(struct conntrack4_net
),
421 static int __init
nf_conntrack_l3proto_ipv4_init(void)
427 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
428 if (WARN_ON(nla_policy_len(ipv4_nla_policy
, CTA_IP_MAX
+ 1) !=
429 nf_conntrack_l3proto_ipv4
.nla_size
))
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
);