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
27 struct nf_ct_udp {
28 unsigned long stream_ts;
29 };
30
31 /* per conntrack: protocol private data */
32 union 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
42 union nf_conntrack_expect_proto {
43 /* insert expect proto private data here */
44 };
45
46 struct nf_conntrack_net_ecache {
47 struct delayed_work dwork;
48 spinlock_t dying_lock;
49 struct hlist_nulls_head dying_list;
50 };
51
52 struct 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
75 struct 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
128 static inline struct nf_conn *
129 nf_ct_to_nf_conn(const struct nf_conntrack *nfct)
130 {
131 return container_of(nfct, struct nf_conn, ct_general);
132 }
133
134 static inline struct nf_conn *
135 nf_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
141 static 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
146 static 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
156 extern struct net init_net;
157
158 static inline struct net *nf_ct_net(const struct nf_conn *ct)
159 {
160 return read_pnet(&ct->ct_net);
161 }
162
163 /* Is this tuple taken? (ignoring any belonging to the given
164 conntrack). */
165 int 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. */
169 static inline struct nf_conn *
170 nf_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
178 void nf_ct_destroy(struct nf_conntrack *nfct);
179
180 void nf_conntrack_tcp_set_closing(struct nf_conn *ct);
181
182 /* decrement reference count on a conntrack */
183 static inline void nf_ct_put(struct nf_conn *ct)
184 {
185 if (ct && refcount_dec_and_test(&ct->ct_general.use))
186 nf_ct_destroy(&ct->ct_general);
187 }
188
189 /* load module; enable/disable conntrack in this namespace */
190 int nf_ct_netns_get(struct net *net, u8 nfproto);
191 void 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 */
197 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
198
199 int nf_conntrack_hash_check_insert(struct nf_conn *ct);
200 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
201
202 bool 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
206 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
207 const struct sk_buff *skb,
208 u32 extra_jiffies, bool do_acct);
209
210 /* Refresh conntrack for this many jiffies and do accounting */
211 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
212 enum ip_conntrack_info ctinfo,
213 const struct sk_buff *skb,
214 u32 extra_jiffies)
215 {
216 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true);
217 }
218
219 /* Refresh conntrack for this many jiffies */
220 static inline void nf_ct_refresh(struct nf_conn *ct,
221 const struct sk_buff *skb,
222 u32 extra_jiffies)
223 {
224 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false);
225 }
226
227 /* kill conntrack and do accounting */
228 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
229 const struct sk_buff *skb);
230
231 /* kill conntrack without accounting */
232 static inline bool nf_ct_kill(struct nf_conn *ct)
233 {
234 return nf_ct_delete(ct, 0, 0);
235 }
236
237 struct nf_ct_iter_data {
238 struct net *net;
239 void *data;
240 u32 portid;
241 int report;
242 };
243
244 /* Iterate over all conntracks: if iter returns true, it's deleted. */
245 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data),
246 const struct nf_ct_iter_data *iter_data);
247
248 /* also set unconfirmed conntracks as dying. Only use in module exit path. */
249 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
250 void *data);
251
252 struct nf_conntrack_zone;
253
254 void nf_conntrack_free(struct nf_conn *ct);
255 struct nf_conn *nf_conntrack_alloc(struct net *net,
256 const struct nf_conntrack_zone *zone,
257 const struct nf_conntrack_tuple *orig,
258 const struct nf_conntrack_tuple *repl,
259 gfp_t gfp);
260
261 static inline int nf_ct_is_template(const struct nf_conn *ct)
262 {
263 return test_bit(IPS_TEMPLATE_BIT, &ct->status);
264 }
265
266 /* It's confirmed if it is, or has been in the hash table. */
267 static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
268 {
269 return test_bit(IPS_CONFIRMED_BIT, &ct->status);
270 }
271
272 static inline int nf_ct_is_dying(const struct nf_conn *ct)
273 {
274 return test_bit(IPS_DYING_BIT, &ct->status);
275 }
276
277 /* Packet is received from loopback */
278 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
279 {
280 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
281 }
282
283 static inline void nf_conntrack_alter_reply(struct nf_conn *ct,
284 const struct nf_conntrack_tuple *newreply)
285 {
286 /* Must be unconfirmed, so not in hash table yet */
287 if (WARN_ON(nf_ct_is_confirmed(ct)))
288 return;
289
290 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
291 }
292
293 #define nfct_time_stamp ((u32)(jiffies))
294
295 /* jiffies until ct expires, 0 if already expired */
296 static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
297 {
298 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
299
300 return max(timeout, 0);
301 }
302
303 static inline bool nf_ct_is_expired(const struct nf_conn *ct)
304 {
305 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0;
306 }
307
308 /* use after obtaining a reference count */
309 static inline bool nf_ct_should_gc(const struct nf_conn *ct)
310 {
311 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
312 !nf_ct_is_dying(ct);
313 }
314
315 #define NF_CT_DAY (86400 * HZ)
316
317 /* Set an arbitrary timeout large enough not to ever expire, this save
318 * us a check for the IPS_OFFLOAD_BIT from the packet path via
319 * nf_ct_is_expired().
320 */
321 static inline void nf_ct_offload_timeout(struct nf_conn *ct)
322 {
323 if (nf_ct_expires(ct) < NF_CT_DAY / 2)
324 WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY);
325 }
326
327 struct kernel_param;
328
329 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
330 int nf_conntrack_hash_resize(unsigned int hashsize);
331
332 extern struct hlist_nulls_head *nf_conntrack_hash;
333 extern unsigned int nf_conntrack_htable_size;
334 extern seqcount_spinlock_t nf_conntrack_generation;
335 extern unsigned int nf_conntrack_max;
336
337 /* must be called with rcu read lock held */
338 static inline void
339 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
340 {
341 struct hlist_nulls_head *hptr;
342 unsigned int sequence, hsz;
343
344 do {
345 sequence = read_seqcount_begin(&nf_conntrack_generation);
346 hsz = nf_conntrack_htable_size;
347 hptr = nf_conntrack_hash;
348 } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
349
350 *hash = hptr;
351 *hsize = hsz;
352 }
353
354 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
355 const struct nf_conntrack_zone *zone,
356 gfp_t flags);
357 void nf_ct_tmpl_free(struct nf_conn *tmpl);
358
359 u32 nf_ct_get_id(const struct nf_conn *ct);
360 u32 nf_conntrack_count(const struct net *net);
361
362 static inline void
363 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
364 {
365 skb_set_nfct(skb, (unsigned long)ct | info);
366 }
367
368 extern unsigned int nf_conntrack_net_id;
369
370 static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net)
371 {
372 return net_generic(net, nf_conntrack_net_id);
373 }
374
375 int nf_ct_skb_network_trim(struct sk_buff *skb, int family);
376 int nf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
377 u16 zone, u8 family, u8 *proto, u16 *mru);
378
379 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count)
380 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
381 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
382
383 #define MODULE_ALIAS_NFCT_HELPER(helper) \
384 MODULE_ALIAS("nfct-helper-" helper)
385
386 #endif /* _NF_CONNTRACK_H */
387
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