1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Connection state tracking for netfilter. This is separated from,
4 * but required by, the (future) NAT layer; it can also be used by an iptables
5 * extension.
6 *
7 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
8 * - generalize L3 protocol dependent part.
9 *
10 * Derived from include/linux/netfiter_ipv4/ip_conntrack.h
11 */
12
13#ifndef _NF_CONNTRACK_H
14#define _NF_CONNTRACK_H
15
16#include <linux/bitops.h>
17#include <linux/compiler.h>
18
19#include <linux/netfilter/nf_conntrack_common.h>
20#include <linux/netfilter/nf_conntrack_tcp.h>
21#include <linux/netfilter/nf_conntrack_dccp.h>
22#include <linux/netfilter/nf_conntrack_sctp.h>
23#include <linux/netfilter/nf_conntrack_proto_gre.h>
24
25#include <net/netfilter/nf_conntrack_tuple.h>
26
27struct nf_ct_udp {
28 unsigned long stream_ts;
29};
30
31/* per conntrack: protocol private data */
32union nf_conntrack_proto {
33 /* insert conntrack proto private data here */
34 struct nf_ct_dccp dccp;
35 struct ip_ct_sctp sctp;
36 struct ip_ct_tcp tcp;
37 struct nf_ct_udp udp;
38 struct nf_ct_gre gre;
39 unsigned int tmpl_padto;
40};
41
42union nf_conntrack_expect_proto {
43 /* insert expect proto private data here */
44};
45
46struct nf_conntrack_net_ecache {
47 struct delayed_work dwork;
48 spinlock_t dying_lock;
49 struct hlist_nulls_head dying_list;
50};
51
52struct nf_conntrack_net {
53 /* only used when new connection is allocated: */
54 atomic_t count;
55 unsigned int expect_count;
56
57 /* only used from work queues, configuration plane, and so on: */
58 unsigned int users4;
59 unsigned int users6;
60 unsigned int users_bridge;
61#ifdef CONFIG_SYSCTL
62 struct ctl_table_header *sysctl_header;
63#endif
64#ifdef CONFIG_NF_CONNTRACK_EVENTS
65 struct nf_conntrack_net_ecache ecache;
66#endif
67};
68
69#include <linux/types.h>
70#include <linux/skbuff.h>
71
72#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
73#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
74
75struct nf_conn {
76 /* Usage count in here is 1 for hash table, 1 per skb,
77 * plus 1 for any connection(s) we are `master' for
78 *
79 * Hint, SKB address this struct and refcnt via skb->_nfct and
80 * helpers nf_conntrack_get() and nf_conntrack_put().
81 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
82 * except that the latter uses internal indirection and does not
83 * result in a conntrack module dependency.
84 * beware nf_ct_get() is different and don't inc refcnt.
85 */
86 struct nf_conntrack ct_general;
87
88 spinlock_t lock;
89 /* jiffies32 when this ct is considered dead */
90 u32 timeout;
91
92#ifdef CONFIG_NF_CONNTRACK_ZONES
93 struct nf_conntrack_zone zone;
94#endif
95 /* XXX should I move this to the tail ? - Y.K */
96 /* These are my tuples; original and reply */
97 struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
98
99 /* Have we seen traffic both ways yet? (bitset) */
100 unsigned long status;
101
102 possible_net_t ct_net;
103
104#if IS_ENABLED(CONFIG_NF_NAT)
105 struct hlist_node nat_bysource;
106#endif
107 /* all members below initialized via memset */
108 struct { } __nfct_init_offset;
109
110 /* If we were expected by an expectation, this will be it */
111 struct nf_conn *master;
112
113#if defined(CONFIG_NF_CONNTRACK_MARK)
114 u_int32_t mark;
115#endif
116
117#ifdef CONFIG_NF_CONNTRACK_SECMARK
118 u_int32_t secmark;
119#endif
120
121 /* Extensions */
122 struct nf_ct_ext *ext;
123
124 /* Storage reserved for other modules, must be the last member */
125 union nf_conntrack_proto proto;
126};
127
128static inline struct nf_conn *
129nf_ct_to_nf_conn(const struct nf_conntrack *nfct)
130{
131 return container_of(nfct, struct nf_conn, ct_general);
132}
133
134static inline struct nf_conn *
135nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
136{
137 return container_of(hash, struct nf_conn,
138 tuplehash[hash->tuple.dst.dir]);
139}
140
141static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
142{
143 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
144}
145
146static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
147{
148 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
149}
150
151#define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
152
153/* get master conntrack via master expectation */
154#define master_ct(conntr) (conntr->master)
155
156extern struct net init_net;
157
158static inline struct net *nf_ct_net(const struct nf_conn *ct)
159{
160 return read_pnet(pnet: &ct->ct_net);
161}
162
163/* Is this tuple taken? (ignoring any belonging to the given
164 conntrack). */
165int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
166 const struct nf_conn *ignored_conntrack);
167
168/* Return conntrack_info and tuple hash for given skb. */
169static inline struct nf_conn *
170nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
171{
172 unsigned long nfct = skb_get_nfct(skb);
173
174 *ctinfo = nfct & NFCT_INFOMASK;
175 return (struct nf_conn *)(nfct & NFCT_PTRMASK);
176}
177
178void nf_ct_destroy(struct nf_conntrack *nfct);
179
180void nf_conntrack_tcp_set_closing(struct nf_conn *ct);
181
182/* decrement reference count on a conntrack */
183static inline void nf_ct_put(struct nf_conn *ct)
184{
185 if (ct && refcount_dec_and_test(r: &ct->ct_general.use))
186 nf_ct_destroy(nfct: &ct->ct_general);
187}
188
189/* load module; enable/disable conntrack in this namespace */
190int nf_ct_netns_get(struct net *net, u8 nfproto);
191void nf_ct_netns_put(struct net *net, u8 nfproto);
192
193/*
194 * Allocate a hashtable of hlist_head (if nulls == 0),
195 * or hlist_nulls_head (if nulls == 1)
196 */
197void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
198
199int nf_conntrack_hash_check_insert(struct nf_conn *ct);
200bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
201
202bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
203 u_int16_t l3num, struct net *net,
204 struct nf_conntrack_tuple *tuple);
205
206void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
207 u32 extra_jiffies, unsigned int bytes);
208
209/* Refresh conntrack for this many jiffies and do accounting */
210static inline void nf_ct_refresh_acct(struct nf_conn *ct,
211 enum ip_conntrack_info ctinfo,
212 const struct sk_buff *skb,
213 u32 extra_jiffies)
214{
215 __nf_ct_refresh_acct(ct, ctinfo, extra_jiffies, bytes: skb->len);
216}
217
218/* Refresh conntrack for this many jiffies */
219static inline void nf_ct_refresh(struct nf_conn *ct,
220 u32 extra_jiffies)
221{
222 __nf_ct_refresh_acct(ct, ctinfo: 0, extra_jiffies, bytes: 0);
223}
224
225/* kill conntrack and do accounting */
226bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
227 const struct sk_buff *skb);
228
229/* kill conntrack without accounting */
230static inline bool nf_ct_kill(struct nf_conn *ct)
231{
232 return nf_ct_delete(ct, pid: 0, report: 0);
233}
234
235struct nf_ct_iter_data {
236 struct net *net;
237 void *data;
238 u32 portid;
239 int report;
240};
241
242/* Iterate over all conntracks: if iter returns true, it's deleted. */
243void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data),
244 const struct nf_ct_iter_data *iter_data);
245
246/* also set unconfirmed conntracks as dying. Only use in module exit path. */
247void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
248 void *data);
249
250struct nf_conntrack_zone;
251
252void nf_conntrack_free(struct nf_conn *ct);
253struct nf_conn *nf_conntrack_alloc(struct net *net,
254 const struct nf_conntrack_zone *zone,
255 const struct nf_conntrack_tuple *orig,
256 const struct nf_conntrack_tuple *repl,
257 gfp_t gfp);
258
259static inline int nf_ct_is_template(const struct nf_conn *ct)
260{
261 return test_bit(IPS_TEMPLATE_BIT, &ct->status);
262}
263
264/* It's confirmed if it is, or has been in the hash table. */
265static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
266{
267 return test_bit(IPS_CONFIRMED_BIT, &ct->status);
268}
269
270static inline int nf_ct_is_dying(const struct nf_conn *ct)
271{
272 return test_bit(IPS_DYING_BIT, &ct->status);
273}
274
275/* Packet is received from loopback */
276static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
277{
278 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
279}
280
281static inline void nf_conntrack_alter_reply(struct nf_conn *ct,
282 const struct nf_conntrack_tuple *newreply)
283{
284 /* Must be unconfirmed, so not in hash table yet */
285 if (WARN_ON(nf_ct_is_confirmed(ct)))
286 return;
287
288 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
289}
290
291#define nfct_time_stamp ((u32)(jiffies))
292
293/* jiffies until ct expires, 0 if already expired */
294static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
295{
296 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
297
298 return max(timeout, 0);
299}
300
301static inline bool nf_ct_is_expired(const struct nf_conn *ct)
302{
303 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0;
304}
305
306/* use after obtaining a reference count */
307static inline bool nf_ct_should_gc(const struct nf_conn *ct)
308{
309 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
310 !nf_ct_is_dying(ct);
311}
312
313#define NF_CT_DAY (86400 * HZ)
314
315struct kernel_param;
316
317int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
318int nf_conntrack_hash_resize(unsigned int hashsize);
319
320extern struct hlist_nulls_head *nf_conntrack_hash;
321extern unsigned int nf_conntrack_htable_size;
322extern seqcount_spinlock_t nf_conntrack_generation;
323extern unsigned int nf_conntrack_max;
324
325/* must be called with rcu read lock held */
326static inline void
327nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
328{
329 struct hlist_nulls_head *hptr;
330 unsigned int sequence, hsz;
331
332 do {
333 sequence = read_seqcount_begin(&nf_conntrack_generation);
334 hsz = nf_conntrack_htable_size;
335 hptr = nf_conntrack_hash;
336 } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
337
338 *hash = hptr;
339 *hsize = hsz;
340}
341
342struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
343 const struct nf_conntrack_zone *zone,
344 gfp_t flags);
345void nf_ct_tmpl_free(struct nf_conn *tmpl);
346
347u32 nf_ct_get_id(const struct nf_conn *ct);
348u32 nf_conntrack_count(const struct net *net);
349
350static inline void
351nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
352{
353 skb_set_nfct(skb, nfct: (unsigned long)ct | info);
354}
355
356extern unsigned int nf_conntrack_net_id;
357
358static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net)
359{
360 return net_generic(net, id: nf_conntrack_net_id);
361}
362
363int nf_ct_skb_network_trim(struct sk_buff *skb, int family);
364int nf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
365 u16 zone, u8 family, u8 *proto, u16 *mru);
366
367#define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count)
368#define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
369#define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
370
371#define MODULE_ALIAS_NFCT_HELPER(helper) \
372 MODULE_ALIAS("nfct-helper-" helper)
373
374#endif /* _NF_CONNTRACK_H */
375

source code of linux/include/net/netfilter/nf_conntrack.h