1 /* SPDX-License-Identifier: GPL-2.0 */
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
7 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
8 * - generalize L3 protocol dependent part.
10 * Derived from include/linux/netfiter_ipv4/ip_conntrack.h
13 #ifndef _NF_CONNTRACK_H
14 #define _NF_CONNTRACK_H
16 #include <linux/bitops.h>
17 #include <linux/compiler.h>
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>
25 #include <net/netfilter/nf_conntrack_tuple.h>
28 unsigned long stream_ts;
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;
39 unsigned int tmpl_padto;
42 union nf_conntrack_expect_proto {
43 /* insert expect proto private data here */
46 struct nf_conntrack_net_ecache {
47 struct delayed_work dwork;
48 spinlock_t dying_lock;
49 struct hlist_nulls_head dying_list;
52 struct nf_conntrack_net {
53 /* only used when new connection is allocated: */
55 unsigned int expect_count;
56 u8 sysctl_auto_assign_helper;
57 bool auto_assign_helper_warned;
59 /* only used from work queues, configuration plane, and so on: */
62 unsigned int users_bridge;
64 struct ctl_table_header *sysctl_header;
66 #ifdef CONFIG_NF_CONNTRACK_EVENTS
67 struct nf_conntrack_net_ecache ecache;
71 #include <linux/types.h>
72 #include <linux/skbuff.h>
74 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
75 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
78 /* Usage count in here is 1 for hash table, 1 per skb,
79 * plus 1 for any connection(s) we are `master' for
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.
88 struct nf_conntrack ct_general;
91 /* jiffies32 when this ct is considered dead */
94 #ifdef CONFIG_NF_CONNTRACK_ZONES
95 struct nf_conntrack_zone zone;
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];
101 /* Have we seen traffic both ways yet? (bitset) */
102 unsigned long status;
104 possible_net_t ct_net;
106 #if IS_ENABLED(CONFIG_NF_NAT)
107 struct hlist_node nat_bysource;
109 /* all members below initialized via memset */
110 struct { } __nfct_init_offset;
112 /* If we were expected by an expectation, this will be it */
113 struct nf_conn *master;
115 #if defined(CONFIG_NF_CONNTRACK_MARK)
119 #ifdef CONFIG_NF_CONNTRACK_SECMARK
124 struct nf_ct_ext *ext;
126 /* Storage reserved for other modules, must be the last member */
127 union nf_conntrack_proto proto;
130 static inline struct nf_conn *
131 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
133 return container_of(hash, struct nf_conn,
134 tuplehash[hash->tuple.dst.dir]);
137 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
139 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
142 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
144 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
147 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
149 /* get master conntrack via master expectation */
150 #define master_ct(conntr) (conntr->master)
152 extern struct net init_net;
154 static inline struct net *nf_ct_net(const struct nf_conn *ct)
156 return read_pnet(&ct->ct_net);
159 /* Alter reply tuple (maybe alter helper). */
160 void nf_conntrack_alter_reply(struct nf_conn *ct,
161 const struct nf_conntrack_tuple *newreply);
163 /* Is this tuple taken? (ignoring any belonging to the given
165 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
166 const struct nf_conn *ignored_conntrack);
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)
172 unsigned long nfct = skb_get_nfct(skb);
174 *ctinfo = nfct & NFCT_INFOMASK;
175 return (struct nf_conn *)(nfct & NFCT_PTRMASK);
178 void nf_ct_destroy(struct nf_conntrack *nfct);
180 /* decrement reference count on a conntrack */
181 static inline void nf_ct_put(struct nf_conn *ct)
183 if (ct && refcount_dec_and_test(&ct->ct_general.use))
184 nf_ct_destroy(&ct->ct_general);
187 /* Protocol module loading */
188 int nf_ct_l3proto_try_module_get(unsigned short l3proto);
189 void nf_ct_l3proto_module_put(unsigned short l3proto);
191 /* load module; enable/disable conntrack in this namespace */
192 int nf_ct_netns_get(struct net *net, u8 nfproto);
193 void nf_ct_netns_put(struct net *net, u8 nfproto);
196 * Allocate a hashtable of hlist_head (if nulls == 0),
197 * or hlist_nulls_head (if nulls == 1)
199 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
201 int nf_conntrack_hash_check_insert(struct nf_conn *ct);
202 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
204 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
205 u_int16_t l3num, struct net *net,
206 struct nf_conntrack_tuple *tuple);
208 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
209 const struct sk_buff *skb,
210 u32 extra_jiffies, bool do_acct);
212 /* Refresh conntrack for this many jiffies and do accounting */
213 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
214 enum ip_conntrack_info ctinfo,
215 const struct sk_buff *skb,
218 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true);
221 /* Refresh conntrack for this many jiffies */
222 static inline void nf_ct_refresh(struct nf_conn *ct,
223 const struct sk_buff *skb,
226 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false);
229 /* kill conntrack and do accounting */
230 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
231 const struct sk_buff *skb);
233 /* kill conntrack without accounting */
234 static inline bool nf_ct_kill(struct nf_conn *ct)
236 return nf_ct_delete(ct, 0, 0);
239 struct nf_ct_iter_data {
246 /* Iterate over all conntracks: if iter returns true, it's deleted. */
247 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data),
248 const struct nf_ct_iter_data *iter_data);
250 /* also set unconfirmed conntracks as dying. Only use in module exit path. */
251 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
254 struct nf_conntrack_zone;
256 void nf_conntrack_free(struct nf_conn *ct);
257 struct nf_conn *nf_conntrack_alloc(struct net *net,
258 const struct nf_conntrack_zone *zone,
259 const struct nf_conntrack_tuple *orig,
260 const struct nf_conntrack_tuple *repl,
263 static inline int nf_ct_is_template(const struct nf_conn *ct)
265 return test_bit(IPS_TEMPLATE_BIT, &ct->status);
268 /* It's confirmed if it is, or has been in the hash table. */
269 static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
271 return test_bit(IPS_CONFIRMED_BIT, &ct->status);
274 static inline int nf_ct_is_dying(const struct nf_conn *ct)
276 return test_bit(IPS_DYING_BIT, &ct->status);
279 /* Packet is received from loopback */
280 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
282 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
285 #define nfct_time_stamp ((u32)(jiffies))
287 /* jiffies until ct expires, 0 if already expired */
288 static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
290 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
292 return max(timeout, 0);
295 static inline bool nf_ct_is_expired(const struct nf_conn *ct)
297 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0;
300 /* use after obtaining a reference count */
301 static inline bool nf_ct_should_gc(const struct nf_conn *ct)
303 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
307 #define NF_CT_DAY (86400 * HZ)
309 /* Set an arbitrary timeout large enough not to ever expire, this save
310 * us a check for the IPS_OFFLOAD_BIT from the packet path via
311 * nf_ct_is_expired().
313 static inline void nf_ct_offload_timeout(struct nf_conn *ct)
315 if (nf_ct_expires(ct) < NF_CT_DAY / 2)
316 WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY);
321 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
322 int nf_conntrack_hash_resize(unsigned int hashsize);
324 extern struct hlist_nulls_head *nf_conntrack_hash;
325 extern unsigned int nf_conntrack_htable_size;
326 extern seqcount_spinlock_t nf_conntrack_generation;
327 extern unsigned int nf_conntrack_max;
329 /* must be called with rcu read lock held */
331 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
333 struct hlist_nulls_head *hptr;
334 unsigned int sequence, hsz;
337 sequence = read_seqcount_begin(&nf_conntrack_generation);
338 hsz = nf_conntrack_htable_size;
339 hptr = nf_conntrack_hash;
340 } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
346 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
347 const struct nf_conntrack_zone *zone,
349 void nf_ct_tmpl_free(struct nf_conn *tmpl);
351 u32 nf_ct_get_id(const struct nf_conn *ct);
352 u32 nf_conntrack_count(const struct net *net);
355 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
357 skb_set_nfct(skb, (unsigned long)ct | info);
360 extern unsigned int nf_conntrack_net_id;
362 static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net)
364 return net_generic(net, nf_conntrack_net_id);
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))
371 #define MODULE_ALIAS_NFCT_HELPER(helper) \
372 MODULE_ALIAS("nfct-helper-" helper)
374 #endif /* _NF_CONNTRACK_H */