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_vendor.h>
19 #include <linux/android_kabi.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_OEM_DATA(1);
130 ANDROID_KABI_RESERVE(1);
131 ANDROID_KABI_RESERVE(2);
132 };
133
134 static inline struct nf_conn *
nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash * hash)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
nf_ct_l3num(const struct nf_conn * ct)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
nf_ct_protonum(const struct nf_conn * ct)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
nf_ct_net(const struct nf_conn * ct)158 static inline struct net *nf_ct_net(const struct nf_conn *ct)
159 {
160 return read_pnet(&ct->ct_net);
161 }
162
163 /* Alter reply tuple (maybe alter helper). */
164 void nf_conntrack_alter_reply(struct nf_conn *ct,
165 const struct nf_conntrack_tuple *newreply);
166
167 /* Is this tuple taken? (ignoring any belonging to the given
168 conntrack). */
169 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
170 const struct nf_conn *ignored_conntrack);
171
172 /* Return conntrack_info and tuple hash for given skb. */
173 static inline struct nf_conn *
nf_ct_get(const struct sk_buff * skb,enum ip_conntrack_info * ctinfo)174 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
175 {
176 unsigned long nfct = skb_get_nfct(skb);
177
178 *ctinfo = nfct & NFCT_INFOMASK;
179 return (struct nf_conn *)(nfct & NFCT_PTRMASK);
180 }
181
182 void nf_ct_destroy(struct nf_conntrack *nfct);
183
184 /* decrement reference count on a conntrack */
nf_ct_put(struct nf_conn * ct)185 static inline void nf_ct_put(struct nf_conn *ct)
186 {
187 if (ct && refcount_dec_and_test(&ct->ct_general.use))
188 nf_ct_destroy(&ct->ct_general);
189 }
190
191 /* Protocol module loading */
192 int nf_ct_l3proto_try_module_get(unsigned short l3proto);
193 void nf_ct_l3proto_module_put(unsigned short l3proto);
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
289 #define nfct_time_stamp ((u32)(jiffies))
290
291 /* jiffies until ct expires, 0 if already expired */
nf_ct_expires(const struct nf_conn * ct)292 static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
293 {
294 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
295
296 return max(timeout, 0);
297 }
298
nf_ct_is_expired(const struct nf_conn * ct)299 static inline bool nf_ct_is_expired(const struct nf_conn *ct)
300 {
301 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0;
302 }
303
304 /* use after obtaining a reference count */
nf_ct_should_gc(const struct nf_conn * ct)305 static inline bool nf_ct_should_gc(const struct nf_conn *ct)
306 {
307 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
308 !nf_ct_is_dying(ct);
309 }
310
311 #define NF_CT_DAY (86400 * HZ)
312
313 /* Set an arbitrary timeout large enough not to ever expire, this save
314 * us a check for the IPS_OFFLOAD_BIT from the packet path via
315 * nf_ct_is_expired().
316 */
nf_ct_offload_timeout(struct nf_conn * ct)317 static inline void nf_ct_offload_timeout(struct nf_conn *ct)
318 {
319 if (nf_ct_expires(ct) < NF_CT_DAY / 2)
320 WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY);
321 }
322
323 struct kernel_param;
324
325 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
326 int nf_conntrack_hash_resize(unsigned int hashsize);
327
328 extern struct hlist_nulls_head *nf_conntrack_hash;
329 extern unsigned int nf_conntrack_htable_size;
330 extern seqcount_spinlock_t nf_conntrack_generation;
331 extern unsigned int nf_conntrack_max;
332
333 /* must be called with rcu read lock held */
334 static inline void
nf_conntrack_get_ht(struct hlist_nulls_head ** hash,unsigned int * hsize)335 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
336 {
337 struct hlist_nulls_head *hptr;
338 unsigned int sequence, hsz;
339
340 do {
341 sequence = read_seqcount_begin(&nf_conntrack_generation);
342 hsz = nf_conntrack_htable_size;
343 hptr = nf_conntrack_hash;
344 } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
345
346 *hash = hptr;
347 *hsize = hsz;
348 }
349
350 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
351 const struct nf_conntrack_zone *zone,
352 gfp_t flags);
353 void nf_ct_tmpl_free(struct nf_conn *tmpl);
354
355 u32 nf_ct_get_id(const struct nf_conn *ct);
356 u32 nf_conntrack_count(const struct net *net);
357
358 static inline void
nf_ct_set(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info info)359 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
360 {
361 skb_set_nfct(skb, (unsigned long)ct | info);
362 }
363
364 extern unsigned int nf_conntrack_net_id;
365
nf_ct_pernet(const struct net * net)366 static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net)
367 {
368 return net_generic(net, nf_conntrack_net_id);
369 }
370
371 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count)
372 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
373 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
374
375 #define MODULE_ALIAS_NFCT_HELPER(helper) \
376 MODULE_ALIAS("nfct-helper-" helper)
377
378 #endif /* _NF_CONNTRACK_H */
379