include/net/netfilter/nf_conntrack.h

   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 #ifdef __KERNEL__
  18 #include <linux/config.h>
  19 #include <linux/bitops.h>
  20 #include <linux/compiler.h>
  21 #include <asm/atomic.h>
  22
  23 #include <linux/netfilter/nf_conntrack_tcp.h>
  24 #include <linux/netfilter/nf_conntrack_sctp.h>
  25 #include <net/netfilter/ipv4/nf_conntrack_icmp.h>
  26 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
  27
  28 #include <net/netfilter/nf_conntrack_tuple.h>
  29
  30 /* per conntrack: protocol private data */
  31 union nf_conntrack_proto {
  32         /* insert conntrack proto private data here */
  33         struct ip_ct_sctp sctp;
  34         struct ip_ct_tcp tcp;
  35         struct ip_ct_icmp icmp;
  36         struct nf_ct_icmpv6 icmpv6;
  37 };
  38
  39 union nf_conntrack_expect_proto {
  40         /* insert expect proto private data here */
  41 };
  42
  43 /* Add protocol helper include file here */
  44 #include <linux/netfilter/nf_conntrack_ftp.h>
  45
  46 /* per conntrack: application helper private data */
  47 union nf_conntrack_help {
  48         /* insert conntrack helper private data (master) here */
  49         struct ip_ct_ftp_master ct_ftp_info;
  50 };
  51
  52 #include <linux/types.h>
  53 #include <linux/skbuff.h>
  54
  55 #ifdef CONFIG_NETFILTER_DEBUG
  56 #define NF_CT_ASSERT(x)                                                 \
  57 do {                                                                    \
  58         if (!(x))                                                       \
  59                 /* Wooah!  I'm tripping my conntrack in a frenzy of     \
  60                    netplay... */                                        \
  61                 printk("NF_CT_ASSERT: %s:%i(%s)\n",                     \
  62                        __FILE__, __LINE__, __FUNCTION__);               \
  63 } while(0)
  64 #else
  65 #define NF_CT_ASSERT(x)
  66 #endif
  67
  68 struct nf_conntrack_helper;
  69
  70 /* nf_conn feature for connections that have a helper */
  71 struct nf_conn_help {
  72         /* Helper. if any */
  73         struct nf_conntrack_helper *helper;
  74
  75         union nf_conntrack_help help;
  76
  77         /* Current number of expected connections */
  78         unsigned int expecting;
  79 };
  80
  81
  82 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  83 struct nf_conn
  84 {
  85         /* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
  86            plus 1 for any connection(s) we are `master' for */
  87         struct nf_conntrack ct_general;
  88
  89         /* XXX should I move this to the tail ? - Y.K */
  90         /* These are my tuples; original and reply */
  91         struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  92
  93         /* Have we seen traffic both ways yet? (bitset) */
  94         unsigned long status;
  95
  96         /* If we were expected by an expectation, this will be it */
  97         struct nf_conn *master;
  98
  99         /* Timer function; drops refcnt when it goes off. */
 100         struct timer_list timeout;
 101
 102 #ifdef CONFIG_NF_CT_ACCT
 103         /* Accounting Information (same cache line as other written members) */
 104         struct ip_conntrack_counter counters[IP_CT_DIR_MAX];
 105 #endif
 106
 107         /* Unique ID that identifies this conntrack*/
 108         unsigned int id;
 109
 110         /* features - nat, helper, ... used by allocating system */
 111         u_int32_t features;
 112
 113 #if defined(CONFIG_NF_CONNTRACK_MARK)
 114         u_int32_t mark;
 115 #endif
 116
 117 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 118         u_int32_t secmark;
 119 #endif
 120
 121         /* Storage reserved for other modules: */
 122         union nf_conntrack_proto proto;
 123
 124         /* features dynamically at the end: helper, nat (both optional) */
 125         char data[0];
 126 };
 127
 128 struct nf_conntrack_expect
 129 {
 130         /* Internal linked list (global expectation list) */
 131         struct list_head list;
 132
 133         /* We expect this tuple, with the following mask */
 134         struct nf_conntrack_tuple tuple, mask;
 135
 136         /* Function to call after setup and insertion */
 137         void (*expectfn)(struct nf_conn *new,
 138                          struct nf_conntrack_expect *this);
 139
 140         /* The conntrack of the master connection */
 141         struct nf_conn *master;
 142
 143         /* Timer function; deletes the expectation. */
 144         struct timer_list timeout;
 145
 146         /* Usage count. */
 147         atomic_t use;
 148
 149         /* Unique ID */
 150         unsigned int id;
 151
 152         /* Flags */
 153         unsigned int flags;
 154
 155 #ifdef CONFIG_NF_NAT_NEEDED
 156         /* This is the original per-proto part, used to map the
 157          * expected connection the way the recipient expects. */
 158         union nf_conntrack_manip_proto saved_proto;
 159         /* Direction relative to the master connection. */
 160         enum ip_conntrack_dir dir;
 161 #endif
 162 };
 163
 164 #define NF_CT_EXPECT_PERMANENT 0x1
 165
 166 static inline struct nf_conn *
 167 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 168 {
 169         return container_of(hash, struct nf_conn,
 170                             tuplehash[hash->tuple.dst.dir]);
 171 }
 172
 173 /* get master conntrack via master expectation */
 174 #define master_ct(conntr) (conntr->master)
 175
 176 /* Alter reply tuple (maybe alter helper). */
 177 extern void
 178 nf_conntrack_alter_reply(struct nf_conn *conntrack,
 179                          const struct nf_conntrack_tuple *newreply);
 180
 181 /* Is this tuple taken? (ignoring any belonging to the given
 182    conntrack). */
 183 extern int
 184 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 185                          const struct nf_conn *ignored_conntrack);
 186
 187 /* Return conntrack_info and tuple hash for given skb. */
 188 static inline struct nf_conn *
 189 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 190 {
 191         *ctinfo = skb->nfctinfo;
 192         return (struct nf_conn *)skb->nfct;
 193 }
 194
 195 /* decrement reference count on a conntrack */
 196 static inline void nf_ct_put(struct nf_conn *ct)
 197 {
 198         NF_CT_ASSERT(ct);
 199         nf_conntrack_put(&ct->ct_general);
 200 }
 201
 202 /* Protocol module loading */
 203 extern int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 204 extern void nf_ct_l3proto_module_put(unsigned short l3proto);
 205
 206 extern struct nf_conntrack_tuple_hash *
 207 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 208                     const struct nf_conn *ignored_conntrack);
 209
 210 extern void nf_conntrack_hash_insert(struct nf_conn *ct);
 211
 212 extern struct nf_conntrack_expect *
 213 __nf_conntrack_expect_find(const struct nf_conntrack_tuple *tuple);
 214
 215 extern struct nf_conntrack_expect *
 216 nf_conntrack_expect_find(const struct nf_conntrack_tuple *tuple);
 217
 218 extern void nf_ct_unlink_expect(struct nf_conntrack_expect *exp);
 219
 220 extern void nf_ct_remove_expectations(struct nf_conn *ct);
 221
 222 extern void nf_conntrack_flush(void);
 223
 224 extern struct nf_conntrack_helper *
 225 nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple);
 226 extern void nf_ct_helper_put(struct nf_conntrack_helper *helper);
 227
 228 extern struct nf_conntrack_helper *
 229 __nf_conntrack_helper_find_byname(const char *name);
 230
 231 extern int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 232                                 const struct nf_conntrack_tuple *orig);
 233
 234 extern void __nf_ct_refresh_acct(struct nf_conn *ct,
 235                                  enum ip_conntrack_info ctinfo,
 236                                  const struct sk_buff *skb,
 237                                  unsigned long extra_jiffies,
 238                                  int do_acct);
 239
 240 /* Refresh conntrack for this many jiffies and do accounting */
 241 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 242                                       enum ip_conntrack_info ctinfo,
 243                                       const struct sk_buff *skb,
 244                                       unsigned long extra_jiffies)
 245 {
 246         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 247 }
 248
 249 /* Refresh conntrack for this many jiffies */
 250 static inline void nf_ct_refresh(struct nf_conn *ct,
 251                                  const struct sk_buff *skb,
 252                                  unsigned long extra_jiffies)
 253 {
 254         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 255 }
 256
 257 /* These are for NAT.  Icky. */
 258 /* Update TCP window tracking data when NAT mangles the packet */
 259 extern void nf_conntrack_tcp_update(struct sk_buff *skb,
 260                                     unsigned int dataoff,
 261                                     struct nf_conn *conntrack,
 262                                     int dir);
 263
 264 /* Call me when a conntrack is destroyed. */
 265 extern void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
 266
 267 /* Fake conntrack entry for untracked connections */
 268 extern struct nf_conn nf_conntrack_untracked;
 269
 270 extern int nf_ct_no_defrag;
 271
 272 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 273 extern void
 274 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data);
 275 extern void nf_conntrack_free(struct nf_conn *ct);
 276 extern struct nf_conn *
 277 nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 278                    const struct nf_conntrack_tuple *repl);
 279
 280 /* It's confirmed if it is, or has been in the hash table. */
 281 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
 282 {
 283         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 284 }
 285
 286 static inline int nf_ct_is_dying(struct nf_conn *ct)
 287 {
 288         return test_bit(IPS_DYING_BIT, &ct->status);
 289 }
 290
 291 extern unsigned int nf_conntrack_htable_size;
 292 extern int nf_conntrack_checksum;
 293
 294 #define NF_CT_STAT_INC(count) (__get_cpu_var(nf_conntrack_stat).count++)
 295
 296 #ifdef CONFIG_NF_CONNTRACK_EVENTS
 297 #include <linux/notifier.h>
 298 #include <linux/interrupt.h>
 299
 300 struct nf_conntrack_ecache {
 301         struct nf_conn *ct;
 302         unsigned int events;
 303 };
 304 DECLARE_PER_CPU(struct nf_conntrack_ecache, nf_conntrack_ecache);
 305
 306 #define CONNTRACK_ECACHE(x)     (__get_cpu_var(nf_conntrack_ecache).x)
 307
 308 extern struct atomic_notifier_head nf_conntrack_chain;
 309 extern struct atomic_notifier_head nf_conntrack_expect_chain;
 310
 311 static inline int nf_conntrack_register_notifier(struct notifier_block *nb)
 312 {
 313         return atomic_notifier_chain_register(&nf_conntrack_chain, nb);
 314 }
 315
 316 static inline int nf_conntrack_unregister_notifier(struct notifier_block *nb)
 317 {
 318         return atomic_notifier_chain_unregister(&nf_conntrack_chain, nb);
 319 }
 320
 321 static inline int
 322 nf_conntrack_expect_register_notifier(struct notifier_block *nb)
 323 {
 324         return atomic_notifier_chain_register(&nf_conntrack_expect_chain, nb);
 325 }
 326
 327 static inline int
 328 nf_conntrack_expect_unregister_notifier(struct notifier_block *nb)
 329 {
 330         return atomic_notifier_chain_unregister(&nf_conntrack_expect_chain,
 331                         nb);
 332 }
 333
 334 extern void nf_ct_deliver_cached_events(const struct nf_conn *ct);
 335 extern void __nf_ct_event_cache_init(struct nf_conn *ct);
 336
 337 static inline void
 338 nf_conntrack_event_cache(enum ip_conntrack_events event,
 339                          const struct sk_buff *skb)
 340 {
 341         struct nf_conn *ct = (struct nf_conn *)skb->nfct;
 342         struct nf_conntrack_ecache *ecache;
 343
 344         local_bh_disable();
 345         ecache = &__get_cpu_var(nf_conntrack_ecache);
 346         if (ct != ecache->ct)
 347                 __nf_ct_event_cache_init(ct);
 348         ecache->events |= event;
 349         local_bh_enable();
 350 }
 351
 352 static inline void nf_conntrack_event(enum ip_conntrack_events event,
 353                                       struct nf_conn *ct)
 354 {
 355         if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct))
 356                 atomic_notifier_call_chain(&nf_conntrack_chain, event, ct);
 357 }
 358
 359 static inline void
 360 nf_conntrack_expect_event(enum ip_conntrack_expect_events event,
 361                           struct nf_conntrack_expect *exp)
 362 {
 363         atomic_notifier_call_chain(&nf_conntrack_expect_chain, event, exp);
 364 }
 365 #else /* CONFIG_NF_CONNTRACK_EVENTS */
 366 static inline void nf_conntrack_event_cache(enum ip_conntrack_events event,
 367                                             const struct sk_buff *skb) {}
 368 static inline void nf_conntrack_event(enum ip_conntrack_events event,
 369                                       struct nf_conn *ct) {}
 370 static inline void nf_ct_deliver_cached_events(const struct nf_conn *ct) {}
 371 static inline void
 372 nf_conntrack_expect_event(enum ip_conntrack_expect_events event,
 373                           struct nf_conntrack_expect *exp) {}
 374 #endif /* CONFIG_NF_CONNTRACK_EVENTS */
 375
 376 /* no helper, no nat */
 377 #define NF_CT_F_BASIC   0
 378 /* for helper */
 379 #define NF_CT_F_HELP    1
 380 /* for nat. */
 381 #define NF_CT_F_NAT     2
 382 #define NF_CT_F_NUM     4
 383
 384 extern int
 385 nf_conntrack_register_cache(u_int32_t features, const char *name, size_t size);
 386 extern void
 387 nf_conntrack_unregister_cache(u_int32_t features);
 388
 389 /* valid combinations:
 390  * basic: nf_conn, nf_conn .. nf_conn_help
 391  * nat: nf_conn .. nf_conn_nat, nf_conn .. nf_conn_nat, nf_conn help
 392  */
 393 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 394 {
 395         unsigned int offset = sizeof(struct nf_conn);
 396
 397         if (!(ct->features & NF_CT_F_HELP))
 398                 return NULL;
 399
 400         return (struct nf_conn_help *) ((void *)ct + offset);
 401 }
 402
 403 #endif /* __KERNEL__ */
 404 #endif /* _NF_CONNTRACK_H */