1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Structure dynamic extension infrastructure
3 * Copyright (C) 2004 Rusty Russell IBM Corporation
4 * Copyright (C) 2007 Netfilter Core Team <coreteam@netfilter.org>
5 * Copyright (C) 2007 USAGI/WIDE Project <http://www.linux-ipv6.org>
6 */
7#include <linux/kernel.h>
8#include <linux/kmemleak.h>
9#include <linux/module.h>
10#include <linux/mutex.h>
11#include <linux/rcupdate.h>
12#include <linux/slab.h>
13#include <linux/skbuff.h>
14#include <net/netfilter/nf_conntrack_extend.h>
15
16#include <net/netfilter/nf_conntrack_helper.h>
17#include <net/netfilter/nf_conntrack_acct.h>
18#include <net/netfilter/nf_conntrack_seqadj.h>
19#include <net/netfilter/nf_conntrack_ecache.h>
20#include <net/netfilter/nf_conntrack_zones.h>
21#include <net/netfilter/nf_conntrack_timestamp.h>
22#include <net/netfilter/nf_conntrack_timeout.h>
23#include <net/netfilter/nf_conntrack_labels.h>
24#include <net/netfilter/nf_conntrack_synproxy.h>
25#include <net/netfilter/nf_conntrack_act_ct.h>
26#include <net/netfilter/nf_nat.h>
27
28#define NF_CT_EXT_PREALLOC 128u /* conntrack events are on by default */
29
30atomic_t nf_conntrack_ext_genid __read_mostly = ATOMIC_INIT(1);
31
32static const u8 nf_ct_ext_type_len[NF_CT_EXT_NUM] = {
33 [NF_CT_EXT_HELPER] = sizeof(struct nf_conn_help),
34#if IS_ENABLED(CONFIG_NF_NAT)
35 [NF_CT_EXT_NAT] = sizeof(struct nf_conn_nat),
36#endif
37 [NF_CT_EXT_SEQADJ] = sizeof(struct nf_conn_seqadj),
38 [NF_CT_EXT_ACCT] = sizeof(struct nf_conn_acct),
39#ifdef CONFIG_NF_CONNTRACK_EVENTS
40 [NF_CT_EXT_ECACHE] = sizeof(struct nf_conntrack_ecache),
41#endif
42#ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
43 [NF_CT_EXT_TSTAMP] = sizeof(struct nf_conn_tstamp),
44#endif
45#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
46 [NF_CT_EXT_TIMEOUT] = sizeof(struct nf_conn_timeout),
47#endif
48#ifdef CONFIG_NF_CONNTRACK_LABELS
49 [NF_CT_EXT_LABELS] = sizeof(struct nf_conn_labels),
50#endif
51#if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
52 [NF_CT_EXT_SYNPROXY] = sizeof(struct nf_conn_synproxy),
53#endif
54#if IS_ENABLED(CONFIG_NET_ACT_CT)
55 [NF_CT_EXT_ACT_CT] = sizeof(struct nf_conn_act_ct_ext),
56#endif
57};
58
59static __always_inline unsigned int total_extension_size(void)
60{
61 /* remember to add new extensions below */
62 BUILD_BUG_ON(NF_CT_EXT_NUM > 10);
63
64 return sizeof(struct nf_ct_ext) +
65 sizeof(struct nf_conn_help)
66#if IS_ENABLED(CONFIG_NF_NAT)
67 + sizeof(struct nf_conn_nat)
68#endif
69 + sizeof(struct nf_conn_seqadj)
70 + sizeof(struct nf_conn_acct)
71#ifdef CONFIG_NF_CONNTRACK_EVENTS
72 + sizeof(struct nf_conntrack_ecache)
73#endif
74#ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
75 + sizeof(struct nf_conn_tstamp)
76#endif
77#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
78 + sizeof(struct nf_conn_timeout)
79#endif
80#ifdef CONFIG_NF_CONNTRACK_LABELS
81 + sizeof(struct nf_conn_labels)
82#endif
83#if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
84 + sizeof(struct nf_conn_synproxy)
85#endif
86#if IS_ENABLED(CONFIG_NET_ACT_CT)
87 + sizeof(struct nf_conn_act_ct_ext)
88#endif
89 ;
90}
91
92void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
93{
94 unsigned int newlen, newoff, oldlen, alloc;
95 struct nf_ct_ext *new;
96
97 /* Conntrack must not be confirmed to avoid races on reallocation. */
98 WARN_ON(nf_ct_is_confirmed(ct));
99
100 /* struct nf_ct_ext uses u8 to store offsets/size */
101 BUILD_BUG_ON(total_extension_size() > 255u);
102
103 if (ct->ext) {
104 const struct nf_ct_ext *old = ct->ext;
105
106 if (__nf_ct_ext_exist(ext: old, id))
107 return NULL;
108 oldlen = old->len;
109 } else {
110 oldlen = sizeof(*new);
111 }
112
113 newoff = ALIGN(oldlen, __alignof__(struct nf_ct_ext));
114 newlen = newoff + nf_ct_ext_type_len[id];
115
116 alloc = max(newlen, NF_CT_EXT_PREALLOC);
117 new = krealloc(ct->ext, alloc, gfp);
118 if (!new)
119 return NULL;
120
121 if (!ct->ext) {
122 memset(s: new->offset, c: 0, n: sizeof(new->offset));
123 new->gen_id = atomic_read(v: &nf_conntrack_ext_genid);
124 }
125
126 new->offset[id] = newoff;
127 new->len = newlen;
128 memset(s: (void *)new + newoff, c: 0, n: newlen - newoff);
129
130 ct->ext = new;
131 return (void *)new + newoff;
132}
133EXPORT_SYMBOL(nf_ct_ext_add);
134
135/* Use nf_ct_ext_find wrapper. This is only useful for unconfirmed entries. */
136void *__nf_ct_ext_find(const struct nf_ct_ext *ext, u8 id)
137{
138 unsigned int gen_id = atomic_read(v: &nf_conntrack_ext_genid);
139 unsigned int this_id = READ_ONCE(ext->gen_id);
140
141 if (!__nf_ct_ext_exist(ext, id))
142 return NULL;
143
144 if (this_id == 0 || ext->gen_id == gen_id)
145 return (void *)ext + ext->offset[id];
146
147 return NULL;
148}
149EXPORT_SYMBOL(__nf_ct_ext_find);
150
151void nf_ct_ext_bump_genid(void)
152{
153 unsigned int value = atomic_inc_return(v: &nf_conntrack_ext_genid);
154
155 if (value == UINT_MAX)
156 atomic_set(v: &nf_conntrack_ext_genid, i: 1);
157
158 msleep(HZ);
159}
160