1 #ifndef _IP_CONNTRACK_H
2 #define _IP_CONNTRACK_H
3 /* Connection state tracking for netfilter. This is separated from,
4 but required by, the NAT layer; it can also be used by an iptables
5 extension. */
6
7 #include <linux/config.h>
8 #include <linux/netfilter_ipv4/ip_conntrack_tuple.h>
9 #include <linux/bitops.h>
10 #include <asm/atomic.h>
11
12 enum ip_conntrack_info
13 {
14 /* Part of an established connection (either direction). */
15 IP_CT_ESTABLISHED,
16
17 /* Like NEW, but related to an existing connection, or ICMP error
18 (in either direction). */
19 IP_CT_RELATED,
20
21 /* Started a new connection to track (only
22 IP_CT_DIR_ORIGINAL); may be a retransmission. */
23 IP_CT_NEW,
24
25 /* >= this indicates reply direction */
26 IP_CT_IS_REPLY,
27
28 /* Number of distinct IP_CT types (no NEW in reply dirn). */
29 IP_CT_NUMBER = IP_CT_IS_REPLY * 2 - 1
30 };
31
32 /* Bitset representing status of connection. */
33 enum ip_conntrack_status {
34 /* It's an expected connection: bit 0 set. This bit never changed */
35 IPS_EXPECTED_BIT = 0,
36 IPS_EXPECTED = (1 << IPS_EXPECTED_BIT),
37
38 /* We've seen packets both ways: bit 1 set. Can be set, not unset. */
39 IPS_SEEN_REPLY_BIT = 1,
40 IPS_SEEN_REPLY = (1 << IPS_SEEN_REPLY_BIT),
41
42 /* Conntrack should never be early-expired. */
43 IPS_ASSURED_BIT = 2,
44 IPS_ASSURED = (1 << IPS_ASSURED_BIT),
45
46 /* Connection is confirmed: originating packet has left box */
47 IPS_CONFIRMED_BIT = 3,
48 IPS_CONFIRMED = (1 << IPS_CONFIRMED_BIT),
49 };
50
51 #include <linux/netfilter_ipv4/ip_conntrack_tcp.h>
52 #include <linux/netfilter_ipv4/ip_conntrack_icmp.h>
53
54 /* per conntrack: protocol private data */
55 union ip_conntrack_proto {
56 /* insert conntrack proto private data here */
57 struct ip_ct_tcp tcp;
58 struct ip_ct_icmp icmp;
59 };
60
61 union ip_conntrack_expect_proto {
62 /* insert expect proto private data here */
63 };
64
65 /* Add protocol helper include file here */
66 #include <linux/netfilter_ipv4/ip_conntrack_amanda.h>
67
68 #include <linux/netfilter_ipv4/ip_conntrack_ftp.h>
69 #include <linux/netfilter_ipv4/ip_conntrack_irc.h>
70
71 /* per expectation: application helper private data */
72 union ip_conntrack_expect_help {
73 /* insert conntrack helper private data (expect) here */
74 struct ip_ct_amanda_expect exp_amanda_info;
75 struct ip_ct_ftp_expect exp_ftp_info;
76 struct ip_ct_irc_expect exp_irc_info;
77
78 #ifdef CONFIG_IP_NF_NAT_NEEDED
79 union {
80 /* insert nat helper private data (expect) here */
81 } nat;
82 #endif
83 };
84
85 /* per conntrack: application helper private data */
86 union ip_conntrack_help {
87 /* insert conntrack helper private data (master) here */
88 struct ip_ct_ftp_master ct_ftp_info;
89 struct ip_ct_irc_master ct_irc_info;
90 };
91
92 #ifdef CONFIG_IP_NF_NAT_NEEDED
93 #include <linux/netfilter_ipv4/ip_nat.h>
94
95 /* per conntrack: nat application helper private data */
96 union ip_conntrack_nat_help {
97 /* insert nat helper private data here */
98 };
99 #endif
100
101 #ifdef __KERNEL__
102
103 #include <linux/types.h>
104 #include <linux/skbuff.h>
105
106 #ifdef CONFIG_NETFILTER_DEBUG
107 #define IP_NF_ASSERT(x) \
108 do { \
109 if (!(x)) \
110 /* Wooah! I'm tripping my conntrack in a frenzy of \
111 netplay... */ \
112 printk("NF_IP_ASSERT: %s:%i(%s)\n", \
113 __FILE__, __LINE__, __FUNCTION__); \
114 } while(0)
115 #else
116 #define IP_NF_ASSERT(x)
117 #endif
118
119 struct ip_conntrack_expect
120 {
121 /* Internal linked list (global expectation list) */
122 struct list_head list;
123
124 /* reference count */
125 atomic_t use;
126
127 /* expectation list for this master */
128 struct list_head expected_list;
129
130 /* The conntrack of the master connection */
131 struct ip_conntrack *expectant;
132
133 /* The conntrack of the sibling connection, set after
134 * expectation arrived */
135 struct ip_conntrack *sibling;
136
137 /* Tuple saved for conntrack */
138 struct ip_conntrack_tuple ct_tuple;
139
140 /* Timer function; deletes the expectation. */
141 struct timer_list timeout;
142
143 /* Data filled out by the conntrack helpers follow: */
144
145 /* We expect this tuple, with the following mask */
146 struct ip_conntrack_tuple tuple, mask;
147
148 /* Function to call after setup and insertion */
149 int (*expectfn)(struct ip_conntrack *new);
150
151 /* At which sequence number did this expectation occur */
152 u_int32_t seq;
153
154 union ip_conntrack_expect_proto proto;
155
156 union ip_conntrack_expect_help help;
157 };
158
159 struct ip_conntrack_helper;
160
161 struct ip_conntrack
162 {
163 /* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
164 plus 1 for any connection(s) we are `master' for */
165 struct nf_conntrack ct_general;
166
167 /* These are my tuples; original and reply */
168 struct ip_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
169
170 /* Have we seen traffic both ways yet? (bitset) */
171 unsigned long status;
172
173 /* Timer function; drops refcnt when it goes off. */
174 struct timer_list timeout;
175
176 /* If we're expecting another related connection, this will be
177 in expected linked list */
178 struct list_head sibling_list;
179
180 /* Current number of expected connections */
181 unsigned int expecting;
182
183 /* If we were expected by an expectation, this will be it */
184 struct ip_conntrack_expect *master;
185
186 /* Helper, if any. */
187 struct ip_conntrack_helper *helper;
188
189 /* Our various nf_ct_info structs specify *what* relation this
190 packet has to the conntrack */
191 struct nf_ct_info infos[IP_CT_NUMBER];
192
193 /* Storage reserved for other modules: */
194
195 union ip_conntrack_proto proto;
196
197 union ip_conntrack_help help;
198
199 #ifdef CONFIG_IP_NF_NAT_NEEDED
200 struct {
201 struct ip_nat_info info;
202 union ip_conntrack_nat_help help;
203 #if defined(CONFIG_IP_NF_TARGET_MASQUERADE) || \
204 defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
205 int masq_index;
206 #endif
207 } nat;
208 #endif /* CONFIG_IP_NF_NAT_NEEDED */
209
210 };
211
212 /* get master conntrack via master expectation */
213 #define master_ct(conntr) (conntr->master ? conntr->master->expectant : NULL)
214
215 /* Alter reply tuple (maybe alter helper). If it's already taken,
216 return 0 and don't do alteration. */
217 extern int
218 ip_conntrack_alter_reply(struct ip_conntrack *conntrack,
219 const struct ip_conntrack_tuple *newreply);
220
221 /* Is this tuple taken? (ignoring any belonging to the given
222 conntrack). */
223 extern int
224 ip_conntrack_tuple_taken(const struct ip_conntrack_tuple *tuple,
225 const struct ip_conntrack *ignored_conntrack);
226
227 /* Return conntrack_info and tuple hash for given skb. */
228 extern struct ip_conntrack *
229 ip_conntrack_get(struct sk_buff *skb, enum ip_conntrack_info *ctinfo);
230
231 /* decrement reference count on a conntrack */
232 extern void ip_conntrack_put(struct ip_conntrack *ct);
233
234 /* find unconfirmed expectation based on tuple */
235 struct ip_conntrack_expect *
236 ip_conntrack_expect_find_get(const struct ip_conntrack_tuple *tuple);
237
238 /* decrement reference count on an expectation */
239 void ip_conntrack_expect_put(struct ip_conntrack_expect *exp);
240
241 extern int invert_tuplepr(struct ip_conntrack_tuple *inverse,
242 const struct ip_conntrack_tuple *orig);
243
244 /* Refresh conntrack for this many jiffies */
245 extern void ip_ct_refresh(struct ip_conntrack *ct,
246 unsigned long extra_jiffies);
247
248 /* These are for NAT. Icky. */
249 /* Call me when a conntrack is destroyed. */
250 extern void (*ip_conntrack_destroyed)(struct ip_conntrack *conntrack);
251
252 /* Returns new sk_buff, or NULL */
253 struct sk_buff *
254 ip_ct_gather_frags(struct sk_buff *skb, u_int32_t user);
255
256 /* Iterate over all conntracks: if iter returns true, it's deleted. */
257 extern void
258 ip_ct_iterate_cleanup(int (*iter)(struct ip_conntrack *i, void *data),
259 void *data);
260
261 /* It's confirmed if it is, or has been in the hash table. */
is_confirmed(struct ip_conntrack * ct)262 static inline int is_confirmed(struct ip_conntrack *ct)
263 {
264 return test_bit(IPS_CONFIRMED_BIT, &ct->status);
265 }
266
267 extern unsigned int ip_conntrack_htable_size;
268 #endif /* __KERNEL__ */
269 #endif /* _IP_CONNTRACK_H */
270