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 *; |
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(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(r: &ct->ct_general.use)) |
186 | nf_ct_destroy(nfct: &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 , 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 ) |
215 | { |
216 | __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, do_acct: 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 ) |
223 | { |
224 | __nf_ct_refresh_acct(ct, ctinfo: 0, skb, extra_jiffies, do_acct: 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, pid: 0, report: 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, nfct: (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, id: 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 | |