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 */
30 union 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 
38 union nf_conntrack_expect_proto {
39 	/* insert expect proto private data here */
40 };
41 
42 /* Add protocol helper include file here */
43 #include <linux/netfilter/nf_conntrack_ftp.h>
44 #include <linux/netfilter/nf_conntrack_pptp.h>
45 #include <linux/netfilter/nf_conntrack_h323.h>
46 #include <linux/netfilter/nf_conntrack_sane.h>
47 #include <linux/netfilter/nf_conntrack_sip.h>
48 
49 /* per conntrack: application helper private data */
50 union nf_conntrack_help {
51 	/* insert conntrack helper private data (master) here */
52 #if defined(CONFIG_NF_CONNTRACK_FTP) || defined(CONFIG_NF_CONNTRACK_FTP_MODULE)
53 	struct nf_ct_ftp_master ct_ftp_info;
54 #endif
55 #if defined(CONFIG_NF_CONNTRACK_PPTP) || \
56     defined(CONFIG_NF_CONNTRACK_PPTP_MODULE)
57 	struct nf_ct_pptp_master ct_pptp_info;
58 #endif
59 #if defined(CONFIG_NF_CONNTRACK_H323) || \
60     defined(CONFIG_NF_CONNTRACK_H323_MODULE)
61 	struct nf_ct_h323_master ct_h323_info;
62 #endif
63 #if defined(CONFIG_NF_CONNTRACK_SANE) || \
64     defined(CONFIG_NF_CONNTRACK_SANE_MODULE)
65 	struct nf_ct_sane_master ct_sane_info;
66 #endif
67 #if defined(CONFIG_NF_CONNTRACK_SIP) || defined(CONFIG_NF_CONNTRACK_SIP_MODULE)
68 	struct nf_ct_sip_master ct_sip_info;
69 #endif
70 };
71 
72 #include <linux/types.h>
73 #include <linux/skbuff.h>
74 #include <linux/timer.h>
75 
76 #ifdef CONFIG_NETFILTER_DEBUG
77 #define NF_CT_ASSERT(x)		WARN_ON(!(x))
78 #else
79 #define NF_CT_ASSERT(x)
80 #endif
81 
82 struct nf_conntrack_helper;
83 
84 /* Must be kept in sync with the classes defined by helpers */
85 #define NF_CT_MAX_EXPECT_CLASSES	4
86 
87 /* nf_conn feature for connections that have a helper */
88 struct nf_conn_help {
89 	/* Helper. if any */
90 	struct nf_conntrack_helper __rcu *helper;
91 
92 	union nf_conntrack_help help;
93 
94 	struct hlist_head expectations;
95 
96 	/* Current number of expected connections */
97 	u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
98 };
99 
100 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
101 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
102 
103 struct nf_conn {
104 	/* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
105            plus 1 for any connection(s) we are `master' for */
106 	struct nf_conntrack ct_general;
107 
108 	spinlock_t lock;
109 
110 	/* XXX should I move this to the tail ? - Y.K */
111 	/* These are my tuples; original and reply */
112 	struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
113 
114 	/* Have we seen traffic both ways yet? (bitset) */
115 	unsigned long status;
116 
117 	/* If we were expected by an expectation, this will be it */
118 	struct nf_conn *master;
119 
120 	/* Timer function; drops refcnt when it goes off. */
121 	struct timer_list timeout;
122 
123 #if defined(CONFIG_NF_CONNTRACK_MARK)
124 	u_int32_t mark;
125 #endif
126 
127 #ifdef CONFIG_NF_CONNTRACK_SECMARK
128 	u_int32_t secmark;
129 #endif
130 
131 	/* Extensions */
132 	struct nf_ct_ext *ext;
133 #ifdef CONFIG_NET_NS
134 	struct net *ct_net;
135 #endif
136 
137 	/* Storage reserved for other modules, must be the last member */
138 	union nf_conntrack_proto proto;
139 };
140 
141 static inline struct nf_conn *
nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash * hash)142 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
143 {
144 	return container_of(hash, struct nf_conn,
145 			    tuplehash[hash->tuple.dst.dir]);
146 }
147 
nf_ct_l3num(const struct nf_conn * ct)148 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
149 {
150 	return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
151 }
152 
nf_ct_protonum(const struct nf_conn * ct)153 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
154 {
155 	return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
156 }
157 
158 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
159 
160 /* get master conntrack via master expectation */
161 #define master_ct(conntr) (conntr->master)
162 
163 extern struct net init_net;
164 
nf_ct_net(const struct nf_conn * ct)165 static inline struct net *nf_ct_net(const struct nf_conn *ct)
166 {
167 	return read_pnet(&ct->ct_net);
168 }
169 
170 /* Alter reply tuple (maybe alter helper). */
171 extern void
172 nf_conntrack_alter_reply(struct nf_conn *ct,
173 			 const struct nf_conntrack_tuple *newreply);
174 
175 /* Is this tuple taken? (ignoring any belonging to the given
176    conntrack). */
177 extern int
178 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
179 			 const struct nf_conn *ignored_conntrack);
180 
181 /* Return conntrack_info and tuple hash for given skb. */
182 static inline struct nf_conn *
nf_ct_get(const struct sk_buff * skb,enum ip_conntrack_info * ctinfo)183 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
184 {
185 	*ctinfo = skb->nfctinfo;
186 	return (struct nf_conn *)skb->nfct;
187 }
188 
189 /* decrement reference count on a conntrack */
nf_ct_put(struct nf_conn * ct)190 static inline void nf_ct_put(struct nf_conn *ct)
191 {
192 	NF_CT_ASSERT(ct);
193 	nf_conntrack_put(&ct->ct_general);
194 }
195 
196 /* Protocol module loading */
197 extern int nf_ct_l3proto_try_module_get(unsigned short l3proto);
198 extern void nf_ct_l3proto_module_put(unsigned short l3proto);
199 
200 /*
201  * Allocate a hashtable of hlist_head (if nulls == 0),
202  * or hlist_nulls_head (if nulls == 1)
203  */
204 extern void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
205 
206 extern void nf_ct_free_hashtable(void *hash, unsigned int size);
207 
208 extern struct nf_conntrack_tuple_hash *
209 __nf_conntrack_find(struct net *net, u16 zone,
210 		    const struct nf_conntrack_tuple *tuple);
211 
212 extern int nf_conntrack_hash_check_insert(struct nf_conn *ct);
213 extern void nf_ct_delete_from_lists(struct nf_conn *ct);
214 extern void nf_ct_insert_dying_list(struct nf_conn *ct);
215 
216 extern void nf_conntrack_flush_report(struct net *net, u32 pid, int report);
217 
218 extern bool nf_ct_get_tuplepr(const struct sk_buff *skb,
219 			      unsigned int nhoff, u_int16_t l3num,
220 			      struct nf_conntrack_tuple *tuple);
221 extern bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
222 				 const struct nf_conntrack_tuple *orig);
223 
224 extern void __nf_ct_refresh_acct(struct nf_conn *ct,
225 				 enum ip_conntrack_info ctinfo,
226 				 const struct sk_buff *skb,
227 				 unsigned long extra_jiffies,
228 				 int do_acct);
229 
230 /* Refresh conntrack for this many jiffies and do accounting */
nf_ct_refresh_acct(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct sk_buff * skb,unsigned long extra_jiffies)231 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
232 				      enum ip_conntrack_info ctinfo,
233 				      const struct sk_buff *skb,
234 				      unsigned long extra_jiffies)
235 {
236 	__nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
237 }
238 
239 /* Refresh conntrack for this many jiffies */
nf_ct_refresh(struct nf_conn * ct,const struct sk_buff * skb,unsigned long extra_jiffies)240 static inline void nf_ct_refresh(struct nf_conn *ct,
241 				 const struct sk_buff *skb,
242 				 unsigned long extra_jiffies)
243 {
244 	__nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
245 }
246 
247 extern bool __nf_ct_kill_acct(struct nf_conn *ct,
248 			      enum ip_conntrack_info ctinfo,
249 			      const struct sk_buff *skb,
250 			      int do_acct);
251 
252 /* kill conntrack and do accounting */
nf_ct_kill_acct(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct sk_buff * skb)253 static inline bool nf_ct_kill_acct(struct nf_conn *ct,
254 				   enum ip_conntrack_info ctinfo,
255 				   const struct sk_buff *skb)
256 {
257 	return __nf_ct_kill_acct(ct, ctinfo, skb, 1);
258 }
259 
260 /* kill conntrack without accounting */
nf_ct_kill(struct nf_conn * ct)261 static inline bool nf_ct_kill(struct nf_conn *ct)
262 {
263 	return __nf_ct_kill_acct(ct, 0, NULL, 0);
264 }
265 
266 /* These are for NAT.  Icky. */
267 extern s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
268 			       enum ip_conntrack_dir dir,
269 			       u32 seq);
270 
271 /* Fake conntrack entry for untracked connections */
272 DECLARE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
nf_ct_untracked_get(void)273 static inline struct nf_conn *nf_ct_untracked_get(void)
274 {
275 	return &__raw_get_cpu_var(nf_conntrack_untracked);
276 }
277 extern void nf_ct_untracked_status_or(unsigned long bits);
278 
279 /* Iterate over all conntracks: if iter returns true, it's deleted. */
280 extern void
281 nf_ct_iterate_cleanup(struct net *net, int (*iter)(struct nf_conn *i, void *data), void *data);
282 extern void nf_conntrack_free(struct nf_conn *ct);
283 extern struct nf_conn *
284 nf_conntrack_alloc(struct net *net, u16 zone,
285 		   const struct nf_conntrack_tuple *orig,
286 		   const struct nf_conntrack_tuple *repl,
287 		   gfp_t gfp);
288 
nf_ct_is_template(const struct nf_conn * ct)289 static inline int nf_ct_is_template(const struct nf_conn *ct)
290 {
291 	return test_bit(IPS_TEMPLATE_BIT, &ct->status);
292 }
293 
294 /* It's confirmed if it is, or has been in the hash table. */
nf_ct_is_confirmed(struct nf_conn * ct)295 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
296 {
297 	return test_bit(IPS_CONFIRMED_BIT, &ct->status);
298 }
299 
nf_ct_is_dying(struct nf_conn * ct)300 static inline int nf_ct_is_dying(struct nf_conn *ct)
301 {
302 	return test_bit(IPS_DYING_BIT, &ct->status);
303 }
304 
nf_ct_is_untracked(const struct nf_conn * ct)305 static inline int nf_ct_is_untracked(const struct nf_conn *ct)
306 {
307 	return test_bit(IPS_UNTRACKED_BIT, &ct->status);
308 }
309 
310 /* Packet is received from loopback */
nf_is_loopback_packet(const struct sk_buff * skb)311 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
312 {
313 	return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
314 }
315 
316 struct kernel_param;
317 
318 extern int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
319 extern unsigned int nf_conntrack_htable_size;
320 extern unsigned int nf_conntrack_max;
321 extern unsigned int nf_conntrack_hash_rnd;
322 void init_nf_conntrack_hash_rnd(void);
323 
324 #define NF_CT_STAT_INC(net, count)	\
325 	__this_cpu_inc((net)->ct.stat->count)
326 #define NF_CT_STAT_INC_ATOMIC(net, count)		\
327 do {							\
328 	local_bh_disable();				\
329 	__this_cpu_inc((net)->ct.stat->count);		\
330 	local_bh_enable();				\
331 } while (0)
332 
333 #define MODULE_ALIAS_NFCT_HELPER(helper) \
334         MODULE_ALIAS("nfct-helper-" helper)
335 
336 #endif /* _NF_CONNTRACK_H */
337