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/bitops.h>
  19 #include <linux/compiler.h>
  20 #include <asm/atomic.h>
  21
  22 #include <linux/netfilter/nf_conntrack_tcp.h>
  23 #include <linux/netfilter/nf_conntrack_sctp.h>
  24 #include <net/netfilter/ipv4/nf_conntrack_icmp.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 ip_ct_sctp sctp;
  33         struct ip_ct_tcp tcp;
  34         struct ip_ct_icmp icmp;
  35         struct nf_ct_icmpv6 icmpv6;
  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_h323.h>
  45
  46 /* per conntrack: application helper private data */
  47 union nf_conntrack_help {
  48         /* insert conntrack helper private data (master) here */
  49         struct nf_ct_ftp_master ct_ftp_info;
  50         struct nf_ct_h323_master ct_h323_info;
  51 };
  52
  53 #include <linux/types.h>
  54 #include <linux/skbuff.h>
  55
  56 #ifdef CONFIG_NETFILTER_DEBUG
  57 #define NF_CT_ASSERT(x)                                                 \
  58 do {                                                                    \
  59         if (!(x))                                                       \
  60                 /* Wooah!  I'm tripping my conntrack in a frenzy of     \
  61                    netplay... */                                        \
  62                 printk("NF_CT_ASSERT: %s:%i(%s)\n",                     \
  63                        __FILE__, __LINE__, __FUNCTION__);               \
  64 } while(0)
  65 #else
  66 #define NF_CT_ASSERT(x)
  67 #endif
  68
  69 struct nf_conntrack_helper;
  70
  71 /* nf_conn feature for connections that have a helper */
  72 struct nf_conn_help {
  73         /* Helper. if any */
  74         struct nf_conntrack_helper *helper;
  75
  76         union nf_conntrack_help help;
  77
  78         /* Current number of expected connections */
  79         unsigned int expecting;
  80 };
  81
  82
  83 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  84 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  85
  86 struct nf_conn
  87 {
  88         /* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
  89            plus 1 for any connection(s) we are `master' for */
  90         struct nf_conntrack ct_general;
  91
  92         /* XXX should I move this to the tail ? - Y.K */
  93         /* These are my tuples; original and reply */
  94         struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  95
  96         /* Have we seen traffic both ways yet? (bitset) */
  97         unsigned long status;
  98
  99         /* If we were expected by an expectation, this will be it */
 100         struct nf_conn *master;
 101
 102         /* Timer function; drops refcnt when it goes off. */
 103         struct timer_list timeout;
 104
 105 #ifdef CONFIG_NF_CT_ACCT
 106         /* Accounting Information (same cache line as other written members) */
 107         struct ip_conntrack_counter counters[IP_CT_DIR_MAX];
 108 #endif
 109
 110         /* Unique ID that identifies this conntrack*/
 111         unsigned int id;
 112
 113         /* features - nat, helper, ... used by allocating system */
 114         u_int32_t features;
 115
 116 #if defined(CONFIG_NF_CONNTRACK_MARK)
 117         u_int32_t mark;
 118 #endif
 119
 120 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 121         u_int32_t secmark;
 122 #endif
 123
 124         /* Storage reserved for other modules: */
 125         union nf_conntrack_proto proto;
 126
 127         /* features dynamically at the end: helper, nat (both optional) */
 128         char data[0];
 129 };
 130
 131 static inline struct nf_conn *
 132 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 133 {
 134         return container_of(hash, struct nf_conn,
 135                             tuplehash[hash->tuple.dst.dir]);
 136 }
 137
 138 /* get master conntrack via master expectation */
 139 #define master_ct(conntr) (conntr->master)
 140
 141 /* Alter reply tuple (maybe alter helper). */
 142 extern void
 143 nf_conntrack_alter_reply(struct nf_conn *conntrack,
 144                          const struct nf_conntrack_tuple *newreply);
 145
 146 /* Is this tuple taken? (ignoring any belonging to the given
 147    conntrack). */
 148 extern int
 149 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 150                          const struct nf_conn *ignored_conntrack);
 151
 152 /* Return conntrack_info and tuple hash for given skb. */
 153 static inline struct nf_conn *
 154 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 155 {
 156         *ctinfo = skb->nfctinfo;
 157         return (struct nf_conn *)skb->nfct;
 158 }
 159
 160 /* decrement reference count on a conntrack */
 161 static inline void nf_ct_put(struct nf_conn *ct)
 162 {
 163         NF_CT_ASSERT(ct);
 164         nf_conntrack_put(&ct->ct_general);
 165 }
 166
 167 /* Protocol module loading */
 168 extern int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 169 extern void nf_ct_l3proto_module_put(unsigned short l3proto);
 170
 171 extern struct nf_conntrack_tuple_hash *
 172 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 173                     const struct nf_conn *ignored_conntrack);
 174
 175 extern void nf_conntrack_hash_insert(struct nf_conn *ct);
 176
 177 extern void nf_conntrack_flush(void);
 178
 179 extern struct nf_conntrack_helper *
 180 nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple);
 181 extern void nf_ct_helper_put(struct nf_conntrack_helper *helper);
 182
 183 extern struct nf_conntrack_helper *
 184 __nf_conntrack_helper_find_byname(const char *name);
 185
 186 extern int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 187                                 const struct nf_conntrack_tuple *orig);
 188
 189 extern void __nf_ct_refresh_acct(struct nf_conn *ct,
 190                                  enum ip_conntrack_info ctinfo,
 191                                  const struct sk_buff *skb,
 192                                  unsigned long extra_jiffies,
 193                                  int do_acct);
 194
 195 /* Refresh conntrack for this many jiffies and do accounting */
 196 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 197                                       enum ip_conntrack_info ctinfo,
 198                                       const struct sk_buff *skb,
 199                                       unsigned long extra_jiffies)
 200 {
 201         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 202 }
 203
 204 /* Refresh conntrack for this many jiffies */
 205 static inline void nf_ct_refresh(struct nf_conn *ct,
 206                                  const struct sk_buff *skb,
 207                                  unsigned long extra_jiffies)
 208 {
 209         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 210 }
 211
 212 /* These are for NAT.  Icky. */
 213 /* Update TCP window tracking data when NAT mangles the packet */
 214 extern void nf_conntrack_tcp_update(struct sk_buff *skb,
 215                                     unsigned int dataoff,
 216                                     struct nf_conn *conntrack,
 217                                     int dir);
 218
 219 /* Call me when a conntrack is destroyed. */
 220 extern void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
 221
 222 /* Fake conntrack entry for untracked connections */
 223 extern struct nf_conn nf_conntrack_untracked;
 224
 225 extern int nf_ct_no_defrag;
 226
 227 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 228 extern void
 229 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data);
 230 extern void nf_conntrack_free(struct nf_conn *ct);
 231 extern struct nf_conn *
 232 nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 233                    const struct nf_conntrack_tuple *repl);
 234
 235 /* It's confirmed if it is, or has been in the hash table. */
 236 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
 237 {
 238         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 239 }
 240
 241 static inline int nf_ct_is_dying(struct nf_conn *ct)
 242 {
 243         return test_bit(IPS_DYING_BIT, &ct->status);
 244 }
 245
 246 extern unsigned int nf_conntrack_htable_size;
 247 extern int nf_conntrack_checksum;
 248 extern atomic_t nf_conntrack_count;
 249 extern int nf_conntrack_max;
 250
 251 DECLARE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
 252 #define NF_CT_STAT_INC(count) (__get_cpu_var(nf_conntrack_stat).count++)
 253
 254 /* no helper, no nat */
 255 #define NF_CT_F_BASIC   0
 256 /* for helper */
 257 #define NF_CT_F_HELP    1
 258 /* for nat. */
 259 #define NF_CT_F_NAT     2
 260 #define NF_CT_F_NUM     4
 261
 262 extern int
 263 nf_conntrack_register_cache(u_int32_t features, const char *name, size_t size);
 264 extern void
 265 nf_conntrack_unregister_cache(u_int32_t features);
 266
 267 /* valid combinations:
 268  * basic: nf_conn, nf_conn .. nf_conn_help
 269  * nat: nf_conn .. nf_conn_nat, nf_conn .. nf_conn_nat .. nf_conn help
 270  */
 271 #ifdef CONFIG_NF_NAT_NEEDED
 272 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
 273 {
 274         unsigned int offset = sizeof(struct nf_conn);
 275
 276         if (!(ct->features & NF_CT_F_NAT))
 277                 return NULL;
 278
 279         offset = ALIGN(offset, __alignof__(struct nf_conn_nat));
 280         return (struct nf_conn_nat *) ((void *)ct + offset);
 281 }
 282
 283 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 284 {
 285         unsigned int offset = sizeof(struct nf_conn);
 286
 287         if (!(ct->features & NF_CT_F_HELP))
 288                 return NULL;
 289         if (ct->features & NF_CT_F_NAT) {
 290                 offset = ALIGN(offset, __alignof__(struct nf_conn_nat));
 291                 offset += sizeof(struct nf_conn_nat);
 292         }
 293
 294         offset = ALIGN(offset, __alignof__(struct nf_conn_help));
 295         return (struct nf_conn_help *) ((void *)ct + offset);
 296 }
 297 #else /* No NAT */
 298 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 299 {
 300         unsigned int offset = sizeof(struct nf_conn);
 301
 302         if (!(ct->features & NF_CT_F_HELP))
 303                 return NULL;
 304
 305         offset = ALIGN(offset, __alignof__(struct nf_conn_help));
 306         return (struct nf_conn_help *) ((void *)ct + offset);
 307 }
 308 #endif /* CONFIG_NF_NAT_NEEDED */
 309 #endif /* __KERNEL__ */
 310 #endif /* _NF_CONNTRACK_H */