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/netfilter/nf_conntrack_common.h>
18 #include <linux/bitops.h>
19 #include <linux/compiler.h>
20 #include <linux/atomic.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 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
28 #include <net/netfilter/nf_conntrack_tuple.h>
30 /* per conntrack: protocol private data */
31 union nf_conntrack_proto {
32 /* insert conntrack proto private data here */
33 struct nf_ct_dccp dccp;
34 struct ip_ct_sctp sctp;
37 unsigned int tmpl_padto;
40 union nf_conntrack_expect_proto {
41 /* insert expect proto private data here */
44 struct nf_conntrack_net {
49 #include <linux/types.h>
50 #include <linux/skbuff.h>
52 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
53 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
56 /* Usage count in here is 1 for hash table, 1 per skb,
57 * plus 1 for any connection(s) we are `master' for
59 * Hint, SKB address this struct and refcnt via skb->_nfct and
60 * helpers nf_conntrack_get() and nf_conntrack_put().
61 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
62 * beware nf_ct_get() is different and don't inc refcnt.
64 struct nf_conntrack ct_general;
69 #ifdef CONFIG_NF_CONNTRACK_ZONES
70 struct nf_conntrack_zone zone;
72 /* XXX should I move this to the tail ? - Y.K */
73 /* These are my tuples; original and reply */
74 struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
76 /* Have we seen traffic both ways yet? (bitset) */
79 /* jiffies32 when this ct is considered dead */
82 possible_net_t ct_net;
84 #if IS_ENABLED(CONFIG_NF_NAT)
85 struct hlist_node nat_bysource;
87 /* all members below initialized via memset */
88 u8 __nfct_init_offset[0];
90 /* If we were expected by an expectation, this will be it */
91 struct nf_conn *master;
93 #if defined(CONFIG_NF_CONNTRACK_MARK)
97 #ifdef CONFIG_NF_CONNTRACK_SECMARK
102 struct nf_ct_ext *ext;
104 /* Storage reserved for other modules, must be the last member */
105 union nf_conntrack_proto proto;
108 static inline struct nf_conn *
109 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
111 return container_of(hash, struct nf_conn,
112 tuplehash[hash->tuple.dst.dir]);
115 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
117 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
120 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
122 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
125 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
127 /* get master conntrack via master expectation */
128 #define master_ct(conntr) (conntr->master)
130 extern struct net init_net;
132 static inline struct net *nf_ct_net(const struct nf_conn *ct)
134 return read_pnet(&ct->ct_net);
137 /* Alter reply tuple (maybe alter helper). */
138 void nf_conntrack_alter_reply(struct nf_conn *ct,
139 const struct nf_conntrack_tuple *newreply);
141 /* Is this tuple taken? (ignoring any belonging to the given
143 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
144 const struct nf_conn *ignored_conntrack);
146 #define NFCT_INFOMASK 7UL
147 #define NFCT_PTRMASK ~(NFCT_INFOMASK)
149 /* Return conntrack_info and tuple hash for given skb. */
150 static inline struct nf_conn *
151 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
153 *ctinfo = skb->_nfct & NFCT_INFOMASK;
155 return (struct nf_conn *)(skb->_nfct & NFCT_PTRMASK);
158 /* decrement reference count on a conntrack */
159 static inline void nf_ct_put(struct nf_conn *ct)
162 nf_conntrack_put(&ct->ct_general);
165 /* Protocol module loading */
166 int nf_ct_l3proto_try_module_get(unsigned short l3proto);
167 void nf_ct_l3proto_module_put(unsigned short l3proto);
169 /* load module; enable/disable conntrack in this namespace */
170 int nf_ct_netns_get(struct net *net, u8 nfproto);
171 void nf_ct_netns_put(struct net *net, u8 nfproto);
174 * Allocate a hashtable of hlist_head (if nulls == 0),
175 * or hlist_nulls_head (if nulls == 1)
177 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
179 int nf_conntrack_hash_check_insert(struct nf_conn *ct);
180 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
182 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
183 u_int16_t l3num, struct net *net,
184 struct nf_conntrack_tuple *tuple);
185 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
186 const struct nf_conntrack_tuple *orig);
188 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
189 const struct sk_buff *skb,
190 unsigned long extra_jiffies, int do_acct);
192 /* Refresh conntrack for this many jiffies and do accounting */
193 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
194 enum ip_conntrack_info ctinfo,
195 const struct sk_buff *skb,
196 unsigned long extra_jiffies)
198 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
201 /* Refresh conntrack for this many jiffies */
202 static inline void nf_ct_refresh(struct nf_conn *ct,
203 const struct sk_buff *skb,
204 unsigned long extra_jiffies)
206 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
209 /* kill conntrack and do accounting */
210 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
211 const struct sk_buff *skb);
213 /* kill conntrack without accounting */
214 static inline bool nf_ct_kill(struct nf_conn *ct)
216 return nf_ct_delete(ct, 0, 0);
219 /* Set all unconfirmed conntrack as dying */
220 void nf_ct_unconfirmed_destroy(struct net *);
222 /* Iterate over all conntracks: if iter returns true, it's deleted. */
223 void nf_ct_iterate_cleanup_net(struct net *net,
224 int (*iter)(struct nf_conn *i, void *data),
225 void *data, u32 portid, int report);
227 /* also set unconfirmed conntracks as dying. Only use in module exit path. */
228 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
231 struct nf_conntrack_zone;
233 void nf_conntrack_free(struct nf_conn *ct);
234 struct nf_conn *nf_conntrack_alloc(struct net *net,
235 const struct nf_conntrack_zone *zone,
236 const struct nf_conntrack_tuple *orig,
237 const struct nf_conntrack_tuple *repl,
240 static inline int nf_ct_is_template(const struct nf_conn *ct)
242 return test_bit(IPS_TEMPLATE_BIT, &ct->status);
245 /* It's confirmed if it is, or has been in the hash table. */
246 static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
248 return test_bit(IPS_CONFIRMED_BIT, &ct->status);
251 static inline int nf_ct_is_dying(const struct nf_conn *ct)
253 return test_bit(IPS_DYING_BIT, &ct->status);
256 /* Packet is received from loopback */
257 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
259 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
262 #define nfct_time_stamp ((u32)(jiffies))
264 /* jiffies until ct expires, 0 if already expired */
265 static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
267 s32 timeout = ct->timeout - nfct_time_stamp;
269 return timeout > 0 ? timeout : 0;
272 static inline bool nf_ct_is_expired(const struct nf_conn *ct)
274 return (__s32)(ct->timeout - nfct_time_stamp) <= 0;
277 /* use after obtaining a reference count */
278 static inline bool nf_ct_should_gc(const struct nf_conn *ct)
280 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
286 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
287 int nf_conntrack_hash_resize(unsigned int hashsize);
289 extern struct hlist_nulls_head *nf_conntrack_hash;
290 extern unsigned int nf_conntrack_htable_size;
291 extern seqcount_t nf_conntrack_generation;
292 extern unsigned int nf_conntrack_max;
294 /* must be called with rcu read lock held */
296 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
298 struct hlist_nulls_head *hptr;
299 unsigned int sequence, hsz;
302 sequence = read_seqcount_begin(&nf_conntrack_generation);
303 hsz = nf_conntrack_htable_size;
304 hptr = nf_conntrack_hash;
305 } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
311 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
312 const struct nf_conntrack_zone *zone,
314 void nf_ct_tmpl_free(struct nf_conn *tmpl);
317 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
319 skb->_nfct = (unsigned long)ct | info;
322 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count)
323 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
324 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
326 #define MODULE_ALIAS_NFCT_HELPER(helper) \
327 MODULE_ALIAS("nfct-helper-" helper)
329 #endif /* _NF_CONNTRACK_H */