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 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  71 struct nf_conn
  72 {
  73         /* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
  74            plus 1 for any connection(s) we are `master' for */
  75         struct nf_conntrack ct_general;
  76
  77         /* XXX should I move this to the tail ? - Y.K */
  78         /* These are my tuples; original and reply */
  79         struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  80
  81         /* Have we seen traffic both ways yet? (bitset) */
  82         unsigned long status;
  83
  84         /* Timer function; drops refcnt when it goes off. */
  85         struct timer_list timeout;
  86
  87 #ifdef CONFIG_NF_CT_ACCT
  88         /* Accounting Information (same cache line as other written members) */
  89         struct ip_conntrack_counter counters[IP_CT_DIR_MAX];
  90 #endif
  91         /* If we were expected by an expectation, this will be it */
  92         struct nf_conn *master;
  93
  94         /* Current number of expected connections */
  95         unsigned int expecting;
  96
  97         /* Unique ID that identifies this conntrack*/
  98         unsigned int id;
  99
 100         /* Helper. if any */
 101         struct nf_conntrack_helper *helper;
 102
 103         /* features - nat, helper, ... used by allocating system */
 104         u_int32_t features;
 105
 106         /* Storage reserved for other modules: */
 107
 108         union nf_conntrack_proto proto;
 109
 110 #if defined(CONFIG_NF_CONNTRACK_MARK)
 111         u_int32_t mark;
 112 #endif
 113
 114         /* These members are dynamically allocated. */
 115
 116         union nf_conntrack_help *help;
 117
 118         /* Layer 3 dependent members. (ex: NAT) */
 119         union {
 120                 struct nf_conntrack_ipv4 *ipv4;
 121         } l3proto;
 122         void *data[0];
 123 };
 124
 125 struct nf_conntrack_expect
 126 {
 127         /* Internal linked list (global expectation list) */
 128         struct list_head list;
 129
 130         /* We expect this tuple, with the following mask */
 131         struct nf_conntrack_tuple tuple, mask;
 132
 133         /* Function to call after setup and insertion */
 134         void (*expectfn)(struct nf_conn *new,
 135                          struct nf_conntrack_expect *this);
 136
 137         /* The conntrack of the master connection */
 138         struct nf_conn *master;
 139
 140         /* Timer function; deletes the expectation. */
 141         struct timer_list timeout;
 142
 143         /* Usage count. */
 144         atomic_t use;
 145
 146         /* Unique ID */
 147         unsigned int id;
 148
 149         /* Flags */
 150         unsigned int flags;
 151
 152 #ifdef CONFIG_NF_NAT_NEEDED
 153         /* This is the original per-proto part, used to map the
 154          * expected connection the way the recipient expects. */
 155         union nf_conntrack_manip_proto saved_proto;
 156         /* Direction relative to the master connection. */
 157         enum ip_conntrack_dir dir;
 158 #endif
 159 };
 160
 161 #define NF_CT_EXPECT_PERMANENT 0x1
 162
 163 static inline struct nf_conn *
 164 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 165 {
 166         return container_of(hash, struct nf_conn,
 167                             tuplehash[hash->tuple.dst.dir]);
 168 }
 169
 170 /* get master conntrack via master expectation */
 171 #define master_ct(conntr) (conntr->master)
 172
 173 /* Alter reply tuple (maybe alter helper). */
 174 extern void
 175 nf_conntrack_alter_reply(struct nf_conn *conntrack,
 176                          const struct nf_conntrack_tuple *newreply);
 177
 178 /* Is this tuple taken? (ignoring any belonging to the given
 179    conntrack). */
 180 extern int
 181 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 182                          const struct nf_conn *ignored_conntrack);
 183
 184 /* Return conntrack_info and tuple hash for given skb. */
 185 static inline struct nf_conn *
 186 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 187 {
 188         *ctinfo = skb->nfctinfo;
 189         return (struct nf_conn *)skb->nfct;
 190 }
 191
 192 /* decrement reference count on a conntrack */
 193 static inline void nf_ct_put(struct nf_conn *ct)
 194 {
 195         NF_CT_ASSERT(ct);
 196         nf_conntrack_put(&ct->ct_general);
 197 }
 198
 199 extern struct nf_conntrack_tuple_hash *
 200 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 201                     const struct nf_conn *ignored_conntrack);
 202
 203 extern void nf_conntrack_hash_insert(struct nf_conn *ct);
 204
 205 extern struct nf_conntrack_expect *
 206 __nf_conntrack_expect_find(const struct nf_conntrack_tuple *tuple);
 207
 208 extern struct nf_conntrack_expect *
 209 nf_conntrack_expect_find(const struct nf_conntrack_tuple *tuple);
 210
 211 extern void nf_ct_unlink_expect(struct nf_conntrack_expect *exp);
 212
 213 extern void nf_ct_remove_expectations(struct nf_conn *ct);
 214
 215 extern void nf_conntrack_flush(void);
 216
 217 extern struct nf_conntrack_helper *
 218 nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple);
 219 extern void nf_ct_helper_put(struct nf_conntrack_helper *helper);
 220
 221 extern struct nf_conntrack_helper *
 222 __nf_conntrack_helper_find_byname(const char *name);
 223
 224 extern int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 225                                 const struct nf_conntrack_tuple *orig);
 226
 227 extern void __nf_ct_refresh_acct(struct nf_conn *ct,
 228                                  enum ip_conntrack_info ctinfo,
 229                                  const struct sk_buff *skb,
 230                                  unsigned long extra_jiffies,
 231                                  int do_acct);
 232
 233 /* Refresh conntrack for this many jiffies and do accounting */
 234 static inline 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 {
 239         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 240 }
 241
 242 /* Refresh conntrack for this many jiffies */
 243 static inline void nf_ct_refresh(struct nf_conn *ct,
 244                                  const struct sk_buff *skb,
 245                                  unsigned long extra_jiffies)
 246 {
 247         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 248 }
 249
 250 /* These are for NAT.  Icky. */
 251 /* Update TCP window tracking data when NAT mangles the packet */
 252 extern void nf_conntrack_tcp_update(struct sk_buff *skb,
 253                                     unsigned int dataoff,
 254                                     struct nf_conn *conntrack,
 255                                     int dir);
 256
 257 /* Call me when a conntrack is destroyed. */
 258 extern void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
 259
 260 /* Fake conntrack entry for untracked connections */
 261 extern struct nf_conn nf_conntrack_untracked;
 262
 263 extern int nf_ct_no_defrag;
 264
 265 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 266 extern void
 267 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data);
 268 extern void nf_conntrack_free(struct nf_conn *ct);
 269 extern struct nf_conn *
 270 nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 271                    const struct nf_conntrack_tuple *repl);
 272
 273 /* It's confirmed if it is, or has been in the hash table. */
 274 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
 275 {
 276         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 277 }
 278
 279 static inline int nf_ct_is_dying(struct nf_conn *ct)
 280 {
 281         return test_bit(IPS_DYING_BIT, &ct->status);
 282 }
 283
 284 extern unsigned int nf_conntrack_htable_size;
 285
 286 #define NF_CT_STAT_INC(count) (__get_cpu_var(nf_conntrack_stat).count++)
 287
 288 #ifdef CONFIG_NF_CONNTRACK_EVENTS
 289 #include <linux/notifier.h>
 290 #include <linux/interrupt.h>
 291
 292 struct nf_conntrack_ecache {
 293         struct nf_conn *ct;
 294         unsigned int events;
 295 };
 296 DECLARE_PER_CPU(struct nf_conntrack_ecache, nf_conntrack_ecache);
 297
 298 #define CONNTRACK_ECACHE(x)     (__get_cpu_var(nf_conntrack_ecache).x)
 299
 300 extern struct notifier_block *nf_conntrack_chain;
 301 extern struct notifier_block *nf_conntrack_expect_chain;
 302
 303 static inline int nf_conntrack_register_notifier(struct notifier_block *nb)
 304 {
 305         return notifier_chain_register(&nf_conntrack_chain, nb);
 306 }
 307
 308 static inline int nf_conntrack_unregister_notifier(struct notifier_block *nb)
 309 {
 310         return notifier_chain_unregister(&nf_conntrack_chain, nb);
 311 }
 312
 313 static inline int
 314 nf_conntrack_expect_register_notifier(struct notifier_block *nb)
 315 {
 316         return notifier_chain_register(&nf_conntrack_expect_chain, nb);
 317 }
 318
 319 static inline int
 320 nf_conntrack_expect_unregister_notifier(struct notifier_block *nb)
 321 {
 322         return notifier_chain_unregister(&nf_conntrack_expect_chain, nb);
 323 }
 324
 325 extern void nf_ct_deliver_cached_events(const struct nf_conn *ct);
 326 extern void __nf_ct_event_cache_init(struct nf_conn *ct);
 327
 328 static inline void
 329 nf_conntrack_event_cache(enum ip_conntrack_events event,
 330                          const struct sk_buff *skb)
 331 {
 332         struct nf_conn *ct = (struct nf_conn *)skb->nfct;
 333         struct nf_conntrack_ecache *ecache;
 334
 335         local_bh_disable();
 336         ecache = &__get_cpu_var(nf_conntrack_ecache);
 337         if (ct != ecache->ct)
 338                 __nf_ct_event_cache_init(ct);
 339         ecache->events |= event;
 340         local_bh_enable();
 341 }
 342
 343 static inline void nf_conntrack_event(enum ip_conntrack_events event,
 344                                       struct nf_conn *ct)
 345 {
 346         if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct))
 347                 notifier_call_chain(&nf_conntrack_chain, event, ct);
 348 }
 349
 350 static inline void
 351 nf_conntrack_expect_event(enum ip_conntrack_expect_events event,
 352                           struct nf_conntrack_expect *exp)
 353 {
 354         notifier_call_chain(&nf_conntrack_expect_chain, event, exp);
 355 }
 356 #else /* CONFIG_NF_CONNTRACK_EVENTS */
 357 static inline void nf_conntrack_event_cache(enum ip_conntrack_events event,
 358                                             const struct sk_buff *skb) {}
 359 static inline void nf_conntrack_event(enum ip_conntrack_events event,
 360                                       struct nf_conn *ct) {}
 361 static inline void nf_ct_deliver_cached_events(const struct nf_conn *ct) {}
 362 static inline void
 363 nf_conntrack_expect_event(enum ip_conntrack_expect_events event,
 364                           struct nf_conntrack_expect *exp) {}
 365 #endif /* CONFIG_NF_CONNTRACK_EVENTS */
 366
 367 /* no helper, no nat */
 368 #define NF_CT_F_BASIC   0
 369 /* for helper */
 370 #define NF_CT_F_HELP    1
 371 /* for nat. */
 372 #define NF_CT_F_NAT     2
 373 #define NF_CT_F_NUM     4
 374
 375 extern int
 376 nf_conntrack_register_cache(u_int32_t features, const char *name, size_t size,
 377                             int (*init_conntrack)(struct nf_conn *, u_int32_t));
 378 extern void
 379 nf_conntrack_unregister_cache(u_int32_t features);
 380
 381 #endif /* __KERNEL__ */
 382 #endif /* _NF_CONNTRACK_H */