1/*
2 * Connection state tracking for netfilter.  This is separated from,
3 * but required by, the (future) NAT layer; it can also be used by an iptables
4 * extension.
5 *
6 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
7 *	- generalize L3 protocol dependent part.
8 *
9 * Derived from include/linux/netfiter_ipv4/ip_conntrack.h
10 */
11
12#ifndef _NF_CONNTRACK_H
13#define _NF_CONNTRACK_H
14
15#include <linux/netfilter/nf_conntrack_common.h>
16
17#include <linux/bitops.h>
18#include <linux/compiler.h>
19#include <linux/atomic.h>
20
21#include <linux/netfilter/nf_conntrack_tcp.h>
22#include <linux/netfilter/nf_conntrack_dccp.h>
23#include <linux/netfilter/nf_conntrack_sctp.h>
24#include <linux/netfilter/nf_conntrack_proto_gre.h>
25#include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
26
27#include <net/netfilter/nf_conntrack_tuple.h>
28
29/* per conntrack: protocol private data */
30union nf_conntrack_proto {
31	/* insert conntrack proto private data here */
32	struct nf_ct_dccp dccp;
33	struct ip_ct_sctp sctp;
34	struct ip_ct_tcp tcp;
35	struct nf_ct_gre gre;
36};
37
38union nf_conntrack_expect_proto {
39	/* insert expect proto private data here */
40};
41
42#include <linux/types.h>
43#include <linux/skbuff.h>
44#include <linux/timer.h>
45
46#ifdef CONFIG_NETFILTER_DEBUG
47#define NF_CT_ASSERT(x)		WARN_ON(!(x))
48#else
49#define NF_CT_ASSERT(x)
50#endif
51
52struct nf_conntrack_helper;
53
54/* Must be kept in sync with the classes defined by helpers */
55#define NF_CT_MAX_EXPECT_CLASSES	4
56
57/* nf_conn feature for connections that have a helper */
58struct nf_conn_help {
59	/* Helper. if any */
60	struct nf_conntrack_helper __rcu *helper;
61
62	struct hlist_head expectations;
63
64	/* Current number of expected connections */
65	u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
66
67	/* private helper information. */
68	char data[];
69};
70
71#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
72#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
73
74struct nf_conn {
75	/* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
76	 * plus 1 for any connection(s) we are `master' for
77	 *
78	 * Hint, SKB address this struct and refcnt via skb->nfct and
79	 * helpers nf_conntrack_get() and nf_conntrack_put().
80	 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
81	 * beware nf_ct_get() is different and don't inc refcnt.
82	 */
83	struct nf_conntrack ct_general;
84
85	spinlock_t	lock;
86	u16		cpu;
87
88	/* XXX should I move this to the tail ? - Y.K */
89	/* These are my tuples; original and reply */
90	struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
91
92	/* Have we seen traffic both ways yet? (bitset) */
93	unsigned long status;
94
95	/* Timer function; drops refcnt when it goes off. */
96	struct timer_list timeout;
97
98	possible_net_t ct_net;
99
100	/* all members below initialized via memset */
101	u8 __nfct_init_offset[0];
102
103	/* If we were expected by an expectation, this will be it */
104	struct nf_conn *master;
105
106#if defined(CONFIG_NF_CONNTRACK_MARK)
107	u_int32_t mark;
108#endif
109
110#ifdef CONFIG_NF_CONNTRACK_SECMARK
111	u_int32_t secmark;
112#endif
113
114	/* Extensions */
115	struct nf_ct_ext *ext;
116
117	/* Storage reserved for other modules, must be the last member */
118	union nf_conntrack_proto proto;
119};
120
121static inline struct nf_conn *
122nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
123{
124	return container_of(hash, struct nf_conn,
125			    tuplehash[hash->tuple.dst.dir]);
126}
127
128static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
129{
130	return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
131}
132
133static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
134{
135	return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
136}
137
138#define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
139
140/* get master conntrack via master expectation */
141#define master_ct(conntr) (conntr->master)
142
143extern struct net init_net;
144
145static inline struct net *nf_ct_net(const struct nf_conn *ct)
146{
147	return read_pnet(&ct->ct_net);
148}
149
150/* Alter reply tuple (maybe alter helper). */
151void nf_conntrack_alter_reply(struct nf_conn *ct,
152			      const struct nf_conntrack_tuple *newreply);
153
154/* Is this tuple taken? (ignoring any belonging to the given
155   conntrack). */
156int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
157			     const struct nf_conn *ignored_conntrack);
158
159/* Return conntrack_info and tuple hash for given skb. */
160static inline struct nf_conn *
161nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
162{
163	*ctinfo = skb->nfctinfo;
164	return (struct nf_conn *)skb->nfct;
165}
166
167/* decrement reference count on a conntrack */
168static inline void nf_ct_put(struct nf_conn *ct)
169{
170	NF_CT_ASSERT(ct);
171	nf_conntrack_put(&ct->ct_general);
172}
173
174/* Protocol module loading */
175int nf_ct_l3proto_try_module_get(unsigned short l3proto);
176void nf_ct_l3proto_module_put(unsigned short l3proto);
177
178/*
179 * Allocate a hashtable of hlist_head (if nulls == 0),
180 * or hlist_nulls_head (if nulls == 1)
181 */
182void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
183
184void nf_ct_free_hashtable(void *hash, unsigned int size);
185
186struct nf_conntrack_tuple_hash *
187__nf_conntrack_find(struct net *net, u16 zone,
188		    const struct nf_conntrack_tuple *tuple);
189
190int nf_conntrack_hash_check_insert(struct nf_conn *ct);
191bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
192
193bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
194		       u_int16_t l3num, struct nf_conntrack_tuple *tuple);
195bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
196			  const struct nf_conntrack_tuple *orig);
197
198void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
199			  const struct sk_buff *skb,
200			  unsigned long extra_jiffies, int do_acct);
201
202/* Refresh conntrack for this many jiffies and do accounting */
203static inline void nf_ct_refresh_acct(struct nf_conn *ct,
204				      enum ip_conntrack_info ctinfo,
205				      const struct sk_buff *skb,
206				      unsigned long extra_jiffies)
207{
208	__nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
209}
210
211/* Refresh conntrack for this many jiffies */
212static inline void nf_ct_refresh(struct nf_conn *ct,
213				 const struct sk_buff *skb,
214				 unsigned long extra_jiffies)
215{
216	__nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
217}
218
219bool __nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
220		       const struct sk_buff *skb, int do_acct);
221
222/* kill conntrack and do accounting */
223static inline bool nf_ct_kill_acct(struct nf_conn *ct,
224				   enum ip_conntrack_info ctinfo,
225				   const struct sk_buff *skb)
226{
227	return __nf_ct_kill_acct(ct, ctinfo, skb, 1);
228}
229
230/* kill conntrack without accounting */
231static inline bool nf_ct_kill(struct nf_conn *ct)
232{
233	return __nf_ct_kill_acct(ct, 0, NULL, 0);
234}
235
236/* These are for NAT.  Icky. */
237extern s32 (*nf_ct_nat_offset)(const struct nf_conn *ct,
238			       enum ip_conntrack_dir dir,
239			       u32 seq);
240
241/* Fake conntrack entry for untracked connections */
242DECLARE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
243static inline struct nf_conn *nf_ct_untracked_get(void)
244{
245	return raw_cpu_ptr(&nf_conntrack_untracked);
246}
247void nf_ct_untracked_status_or(unsigned long bits);
248
249/* Iterate over all conntracks: if iter returns true, it's deleted. */
250void nf_ct_iterate_cleanup(struct net *net,
251			   int (*iter)(struct nf_conn *i, void *data),
252			   void *data, u32 portid, int report);
253void nf_conntrack_free(struct nf_conn *ct);
254struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
255				   const struct nf_conntrack_tuple *orig,
256				   const struct nf_conntrack_tuple *repl,
257				   gfp_t gfp);
258
259static inline int nf_ct_is_template(const struct nf_conn *ct)
260{
261	return test_bit(IPS_TEMPLATE_BIT, &ct->status);
262}
263
264/* It's confirmed if it is, or has been in the hash table. */
265static inline int nf_ct_is_confirmed(struct nf_conn *ct)
266{
267	return test_bit(IPS_CONFIRMED_BIT, &ct->status);
268}
269
270static inline int nf_ct_is_dying(struct nf_conn *ct)
271{
272	return test_bit(IPS_DYING_BIT, &ct->status);
273}
274
275static inline int nf_ct_is_untracked(const struct nf_conn *ct)
276{
277	return test_bit(IPS_UNTRACKED_BIT, &ct->status);
278}
279
280/* Packet is received from loopback */
281static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
282{
283	return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
284}
285
286struct kernel_param;
287
288int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
289extern unsigned int nf_conntrack_htable_size;
290extern unsigned int nf_conntrack_max;
291extern unsigned int nf_conntrack_hash_rnd;
292void init_nf_conntrack_hash_rnd(void);
293
294void nf_conntrack_tmpl_insert(struct net *net, struct nf_conn *tmpl);
295
296#define NF_CT_STAT_INC(net, count)	  __this_cpu_inc((net)->ct.stat->count)
297#define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
298
299#define MODULE_ALIAS_NFCT_HELPER(helper) \
300        MODULE_ALIAS("nfct-helper-" helper)
301
302#endif /* _NF_CONNTRACK_H */
303