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 #include <linux/android_kabi.h>
19 #include <linux/android_vendor.h>
20
21 #include <linux/netfilter/nf_conntrack_common.h>
22 #include <linux/netfilter/nf_conntrack_tcp.h>
23 #include <linux/netfilter/nf_conntrack_dccp.h>
24 #include <linux/netfilter/nf_conntrack_sctp.h>
25 #include <linux/netfilter/nf_conntrack_proto_gre.h>
26
27 #include <net/netfilter/nf_conntrack_tuple.h>
28
29 struct nf_ct_udp {
30 unsigned long stream_ts;
31 };
32
33 /* per conntrack: protocol private data */
34 union nf_conntrack_proto {
35 /* insert conntrack proto private data here */
36 struct nf_ct_dccp dccp;
37 struct ip_ct_sctp sctp;
38 struct ip_ct_tcp tcp;
39 struct nf_ct_udp udp;
40 struct nf_ct_gre gre;
41 unsigned int tmpl_padto;
42 };
43
44 union nf_conntrack_expect_proto {
45 /* insert expect proto private data here */
46 };
47
48 struct nf_conntrack_net_ecache {
49 struct delayed_work dwork;
50 spinlock_t dying_lock;
51 struct hlist_nulls_head dying_list;
52 };
53
54 struct nf_conntrack_net {
55 /* only used when new connection is allocated: */
56 atomic_t count;
57 unsigned int expect_count;
58
59 /* only used from work queues, configuration plane, and so on: */
60 unsigned int users4;
61 unsigned int users6;
62 unsigned int users_bridge;
63 #ifdef CONFIG_SYSCTL
64 struct ctl_table_header *sysctl_header;
65 #endif
66 #ifdef CONFIG_NF_CONNTRACK_EVENTS
67 struct nf_conntrack_net_ecache ecache;
68 #endif
69 };
70
71 #include <linux/types.h>
72 #include <linux/skbuff.h>
73
74 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
75 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
76
77 struct nf_conn {
78 /* Usage count in here is 1 for hash table, 1 per skb,
79 * plus 1 for any connection(s) we are `master' for
80 *
81 * Hint, SKB address this struct and refcnt via skb->_nfct and
82 * helpers nf_conntrack_get() and nf_conntrack_put().
83 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
84 * except that the latter uses internal indirection and does not
85 * result in a conntrack module dependency.
86 * beware nf_ct_get() is different and don't inc refcnt.
87 */
88 struct nf_conntrack ct_general;
89
90 spinlock_t lock;
91 /* jiffies32 when this ct is considered dead */
92 u32 timeout;
93
94 #ifdef CONFIG_NF_CONNTRACK_ZONES
95 struct nf_conntrack_zone zone;
96 #endif
97 /* XXX should I move this to the tail ? - Y.K */
98 /* These are my tuples; original and reply */
99 struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
100
101 /* Have we seen traffic both ways yet? (bitset) */
102 unsigned long status;
103
104 possible_net_t ct_net;
105
106 #if IS_ENABLED(CONFIG_NF_NAT)
107 struct hlist_node nat_bysource;
108 #endif
109 /* all members below initialized via memset */
110 struct { } __nfct_init_offset;
111
112 /* If we were expected by an expectation, this will be it */
113 struct nf_conn *master;
114
115 #if defined(CONFIG_NF_CONNTRACK_MARK)
116 u_int32_t mark;
117 #endif
118
119 #ifdef CONFIG_NF_CONNTRACK_SECMARK
120 u_int32_t secmark;
121 #endif
122
123 /* Extensions */
124 struct nf_ct_ext *ext;
125
126 /* Storage reserved for other modules, must be the last member */
127 union nf_conntrack_proto proto;
128
129 ANDROID_KABI_RESERVE(1);
130 ANDROID_KABI_RESERVE(2);
131 ANDROID_OEM_DATA(1);
132 };
133
134 static inline struct nf_conn *
nf_ct_to_nf_conn(const struct nf_conntrack * nfct)135 nf_ct_to_nf_conn(const struct nf_conntrack *nfct)
136 {
137 return container_of(nfct, struct nf_conn, ct_general);
138 }
139
140 static inline struct nf_conn *
nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash * hash)141 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
142 {
143 return container_of(hash, struct nf_conn,
144 tuplehash[hash->tuple.dst.dir]);
145 }
146
nf_ct_l3num(const struct nf_conn * ct)147 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
148 {
149 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
150 }
151
nf_ct_protonum(const struct nf_conn * ct)152 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
153 {
154 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
155 }
156
157 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
158
159 /* get master conntrack via master expectation */
160 #define master_ct(conntr) (conntr->master)
161
162 extern struct net init_net;
163
nf_ct_net(const struct nf_conn * ct)164 static inline struct net *nf_ct_net(const struct nf_conn *ct)
165 {
166 return read_pnet(&ct->ct_net);
167 }
168
169 /* Is this tuple taken? (ignoring any belonging to the given
170 conntrack). */
171 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
172 const struct nf_conn *ignored_conntrack);
173
174 /* Return conntrack_info and tuple hash for given skb. */
175 static inline struct nf_conn *
nf_ct_get(const struct sk_buff * skb,enum ip_conntrack_info * ctinfo)176 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
177 {
178 unsigned long nfct = skb_get_nfct(skb);
179
180 *ctinfo = nfct & NFCT_INFOMASK;
181 return (struct nf_conn *)(nfct & NFCT_PTRMASK);
182 }
183
184 void nf_ct_destroy(struct nf_conntrack *nfct);
185
186 void nf_conntrack_tcp_set_closing(struct nf_conn *ct);
187
188 /* decrement reference count on a conntrack */
nf_ct_put(struct nf_conn * ct)189 static inline void nf_ct_put(struct nf_conn *ct)
190 {
191 if (ct && refcount_dec_and_test(&ct->ct_general.use))
192 nf_ct_destroy(&ct->ct_general);
193 }
194
195 /* load module; enable/disable conntrack in this namespace */
196 int nf_ct_netns_get(struct net *net, u8 nfproto);
197 void nf_ct_netns_put(struct net *net, u8 nfproto);
198
199 /*
200 * Allocate a hashtable of hlist_head (if nulls == 0),
201 * or hlist_nulls_head (if nulls == 1)
202 */
203 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
204
205 int nf_conntrack_hash_check_insert(struct nf_conn *ct);
206 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
207
208 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
209 u_int16_t l3num, struct net *net,
210 struct nf_conntrack_tuple *tuple);
211
212 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
213 const struct sk_buff *skb,
214 u32 extra_jiffies, bool do_acct);
215
216 /* Refresh conntrack for this many jiffies and do accounting */
nf_ct_refresh_acct(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct sk_buff * skb,u32 extra_jiffies)217 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
218 enum ip_conntrack_info ctinfo,
219 const struct sk_buff *skb,
220 u32 extra_jiffies)
221 {
222 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true);
223 }
224
225 /* Refresh conntrack for this many jiffies */
nf_ct_refresh(struct nf_conn * ct,const struct sk_buff * skb,u32 extra_jiffies)226 static inline void nf_ct_refresh(struct nf_conn *ct,
227 const struct sk_buff *skb,
228 u32 extra_jiffies)
229 {
230 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false);
231 }
232
233 /* kill conntrack and do accounting */
234 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
235 const struct sk_buff *skb);
236
237 /* kill conntrack without accounting */
nf_ct_kill(struct nf_conn * ct)238 static inline bool nf_ct_kill(struct nf_conn *ct)
239 {
240 return nf_ct_delete(ct, 0, 0);
241 }
242
243 struct nf_ct_iter_data {
244 struct net *net;
245 void *data;
246 u32 portid;
247 int report;
248 };
249
250 /* Iterate over all conntracks: if iter returns true, it's deleted. */
251 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data),
252 const struct nf_ct_iter_data *iter_data);
253
254 /* also set unconfirmed conntracks as dying. Only use in module exit path. */
255 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
256 void *data);
257
258 struct nf_conntrack_zone;
259
260 void nf_conntrack_free(struct nf_conn *ct);
261 struct nf_conn *nf_conntrack_alloc(struct net *net,
262 const struct nf_conntrack_zone *zone,
263 const struct nf_conntrack_tuple *orig,
264 const struct nf_conntrack_tuple *repl,
265 gfp_t gfp);
266
nf_ct_is_template(const struct nf_conn * ct)267 static inline int nf_ct_is_template(const struct nf_conn *ct)
268 {
269 return test_bit(IPS_TEMPLATE_BIT, &ct->status);
270 }
271
272 /* It's confirmed if it is, or has been in the hash table. */
nf_ct_is_confirmed(const struct nf_conn * ct)273 static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
274 {
275 return test_bit(IPS_CONFIRMED_BIT, &ct->status);
276 }
277
nf_ct_is_dying(const struct nf_conn * ct)278 static inline int nf_ct_is_dying(const struct nf_conn *ct)
279 {
280 return test_bit(IPS_DYING_BIT, &ct->status);
281 }
282
283 /* Packet is received from loopback */
nf_is_loopback_packet(const struct sk_buff * skb)284 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
285 {
286 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
287 }
288
nf_conntrack_alter_reply(struct nf_conn * ct,const struct nf_conntrack_tuple * newreply)289 static inline void nf_conntrack_alter_reply(struct nf_conn *ct,
290 const struct nf_conntrack_tuple *newreply)
291 {
292 /* Must be unconfirmed, so not in hash table yet */
293 if (WARN_ON(nf_ct_is_confirmed(ct)))
294 return;
295
296 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
297 }
298
299 #define nfct_time_stamp ((u32)(jiffies))
300
301 /* jiffies until ct expires, 0 if already expired */
nf_ct_expires(const struct nf_conn * ct)302 static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
303 {
304 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
305
306 return max(timeout, 0);
307 }
308
nf_ct_is_expired(const struct nf_conn * ct)309 static inline bool nf_ct_is_expired(const struct nf_conn *ct)
310 {
311 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0;
312 }
313
314 /* use after obtaining a reference count */
nf_ct_should_gc(const struct nf_conn * ct)315 static inline bool nf_ct_should_gc(const struct nf_conn *ct)
316 {
317 if (!nf_ct_is_confirmed(ct))
318 return false;
319
320 /* load ct->timeout after is_confirmed() test.
321 * Pairs with __nf_conntrack_confirm() which:
322 * 1. Increases ct->timeout value
323 * 2. Inserts ct into rcu hlist
324 * 3. Sets the confirmed bit
325 * 4. Unlocks the hlist lock
326 */
327 smp_acquire__after_ctrl_dep();
328
329 return nf_ct_is_expired(ct) && !nf_ct_is_dying(ct);
330 }
331
332 #define NF_CT_DAY (86400 * HZ)
333
334 /* Set an arbitrary timeout large enough not to ever expire, this save
335 * us a check for the IPS_OFFLOAD_BIT from the packet path via
336 * nf_ct_is_expired().
337 */
nf_ct_offload_timeout(struct nf_conn * ct)338 static inline void nf_ct_offload_timeout(struct nf_conn *ct)
339 {
340 if (nf_ct_expires(ct) < NF_CT_DAY / 2)
341 WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY);
342 }
343
344 struct kernel_param;
345
346 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
347 int nf_conntrack_hash_resize(unsigned int hashsize);
348
349 extern struct hlist_nulls_head *nf_conntrack_hash;
350 extern unsigned int nf_conntrack_htable_size;
351 extern seqcount_spinlock_t nf_conntrack_generation;
352 extern unsigned int nf_conntrack_max;
353
354 /* must be called with rcu read lock held */
355 static inline void
nf_conntrack_get_ht(struct hlist_nulls_head ** hash,unsigned int * hsize)356 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
357 {
358 struct hlist_nulls_head *hptr;
359 unsigned int sequence, hsz;
360
361 do {
362 sequence = read_seqcount_begin(&nf_conntrack_generation);
363 hsz = nf_conntrack_htable_size;
364 hptr = nf_conntrack_hash;
365 } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
366
367 *hash = hptr;
368 *hsize = hsz;
369 }
370
371 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
372 const struct nf_conntrack_zone *zone,
373 gfp_t flags);
374 void nf_ct_tmpl_free(struct nf_conn *tmpl);
375
376 u32 nf_ct_get_id(const struct nf_conn *ct);
377 u32 nf_conntrack_count(const struct net *net);
378
379 static inline void
nf_ct_set(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info info)380 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
381 {
382 skb_set_nfct(skb, (unsigned long)ct | info);
383 }
384
385 extern unsigned int nf_conntrack_net_id;
386
nf_ct_pernet(const struct net * net)387 static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net)
388 {
389 return net_generic(net, nf_conntrack_net_id);
390 }
391
392 int nf_ct_skb_network_trim(struct sk_buff *skb, int family);
393 int nf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
394 u16 zone, u8 family, u8 *proto, u16 *mru);
395
396 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count)
397 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
398 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
399
400 #define MODULE_ALIAS_NFCT_HELPER(helper) \
401 MODULE_ALIAS("nfct-helper-" helper)
402
403 #endif /* _NF_CONNTRACK_H */
404