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 <linux/netfilter/nf_conntrack_proto_gre.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         struct nf_ct_gre gre;
  38 };
  39
  40 union nf_conntrack_expect_proto {
  41         /* insert expect proto private data here */
  42 };
  43
  44 /* Add protocol helper include file here */
  45 #include <linux/netfilter/nf_conntrack_ftp.h>
  46 #include <linux/netfilter/nf_conntrack_pptp.h>
  47 #include <linux/netfilter/nf_conntrack_h323.h>
  48
  49 /* per conntrack: application helper private data */
  50 union nf_conntrack_help {
  51         /* insert conntrack helper private data (master) here */
  52         struct nf_ct_ftp_master ct_ftp_info;
  53         struct nf_ct_pptp_master ct_pptp_info;
  54         struct nf_ct_h323_master ct_h323_info;
  55 };
  56
  57 #include <linux/types.h>
  58 #include <linux/skbuff.h>
  59
  60 #ifdef CONFIG_NETFILTER_DEBUG
  61 #define NF_CT_ASSERT(x)                                                 \
  62 do {                                                                    \
  63         if (!(x))                                                       \
  64                 /* Wooah!  I'm tripping my conntrack in a frenzy of     \
  65                    netplay... */                                        \
  66                 printk("NF_CT_ASSERT: %s:%i(%s)\n",                     \
  67                        __FILE__, __LINE__, __FUNCTION__);               \
  68 } while(0)
  69 #else
  70 #define NF_CT_ASSERT(x)
  71 #endif
  72
  73 struct nf_conntrack_helper;
  74
  75 /* nf_conn feature for connections that have a helper */
  76 struct nf_conn_help {
  77         /* Helper. if any */
  78         struct nf_conntrack_helper *helper;
  79
  80         union nf_conntrack_help help;
  81
  82         /* Current number of expected connections */
  83         unsigned int expecting;
  84 };
  85
  86
  87 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  88 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  89
  90 struct nf_conn
  91 {
  92         /* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
  93            plus 1 for any connection(s) we are `master' for */
  94         struct nf_conntrack ct_general;
  95
  96         /* XXX should I move this to the tail ? - Y.K */
  97         /* These are my tuples; original and reply */
  98         struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  99
 100         /* Have we seen traffic both ways yet? (bitset) */
 101         unsigned long status;
 102
 103         /* If we were expected by an expectation, this will be it */
 104         struct nf_conn *master;
 105
 106         /* Timer function; drops refcnt when it goes off. */
 107         struct timer_list timeout;
 108
 109 #ifdef CONFIG_NF_CT_ACCT
 110         /* Accounting Information (same cache line as other written members) */
 111         struct ip_conntrack_counter counters[IP_CT_DIR_MAX];
 112 #endif
 113
 114         /* Unique ID that identifies this conntrack*/
 115         unsigned int id;
 116
 117         /* features - nat, helper, ... used by allocating system */
 118         u_int32_t features;
 119
 120 #if defined(CONFIG_NF_CONNTRACK_MARK)
 121         u_int32_t mark;
 122 #endif
 123
 124 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 125         u_int32_t secmark;
 126 #endif
 127
 128         /* Storage reserved for other modules: */
 129         union nf_conntrack_proto proto;
 130
 131         /* features dynamically at the end: helper, nat (both optional) */
 132         char data[0];
 133 };
 134
 135 static inline struct nf_conn *
 136 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 137 {
 138         return container_of(hash, struct nf_conn,
 139                             tuplehash[hash->tuple.dst.dir]);
 140 }
 141
 142 /* get master conntrack via master expectation */
 143 #define master_ct(conntr) (conntr->master)
 144
 145 /* Alter reply tuple (maybe alter helper). */
 146 extern void
 147 nf_conntrack_alter_reply(struct nf_conn *conntrack,
 148                          const struct nf_conntrack_tuple *newreply);
 149
 150 /* Is this tuple taken? (ignoring any belonging to the given
 151    conntrack). */
 152 extern int
 153 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 154                          const struct nf_conn *ignored_conntrack);
 155
 156 /* Return conntrack_info and tuple hash for given skb. */
 157 static inline struct nf_conn *
 158 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 159 {
 160         *ctinfo = skb->nfctinfo;
 161         return (struct nf_conn *)skb->nfct;
 162 }
 163
 164 /* decrement reference count on a conntrack */
 165 static inline void nf_ct_put(struct nf_conn *ct)
 166 {
 167         NF_CT_ASSERT(ct);
 168         nf_conntrack_put(&ct->ct_general);
 169 }
 170
 171 /* Protocol module loading */
 172 extern int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 173 extern void nf_ct_l3proto_module_put(unsigned short l3proto);
 174
 175 extern struct nf_conntrack_tuple_hash *
 176 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 177                     const struct nf_conn *ignored_conntrack);
 178
 179 extern void nf_conntrack_hash_insert(struct nf_conn *ct);
 180
 181 extern void nf_conntrack_flush(void);
 182
 183 extern struct nf_conntrack_helper *
 184 nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple);
 185 extern void nf_ct_helper_put(struct nf_conntrack_helper *helper);
 186
 187 extern struct nf_conntrack_helper *
 188 __nf_conntrack_helper_find_byname(const char *name);
 189
 190 extern int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 191                                 const struct nf_conntrack_tuple *orig);
 192
 193 extern void __nf_ct_refresh_acct(struct nf_conn *ct,
 194                                  enum ip_conntrack_info ctinfo,
 195                                  const struct sk_buff *skb,
 196                                  unsigned long extra_jiffies,
 197                                  int do_acct);
 198
 199 /* Refresh conntrack for this many jiffies and do accounting */
 200 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 201                                       enum ip_conntrack_info ctinfo,
 202                                       const struct sk_buff *skb,
 203                                       unsigned long extra_jiffies)
 204 {
 205         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 206 }
 207
 208 /* Refresh conntrack for this many jiffies */
 209 static inline void nf_ct_refresh(struct nf_conn *ct,
 210                                  const struct sk_buff *skb,
 211                                  unsigned long extra_jiffies)
 212 {
 213         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 214 }
 215
 216 /* These are for NAT.  Icky. */
 217 /* Update TCP window tracking data when NAT mangles the packet */
 218 extern void nf_conntrack_tcp_update(struct sk_buff *skb,
 219                                     unsigned int dataoff,
 220                                     struct nf_conn *conntrack,
 221                                     int dir);
 222
 223 /* Call me when a conntrack is destroyed. */
 224 extern void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
 225
 226 /* Fake conntrack entry for untracked connections */
 227 extern struct nf_conn nf_conntrack_untracked;
 228
 229 extern int nf_ct_no_defrag;
 230
 231 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 232 extern void
 233 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data);
 234 extern void nf_conntrack_free(struct nf_conn *ct);
 235 extern struct nf_conn *
 236 nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 237                    const struct nf_conntrack_tuple *repl);
 238
 239 /* It's confirmed if it is, or has been in the hash table. */
 240 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
 241 {
 242         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 243 }
 244
 245 static inline int nf_ct_is_dying(struct nf_conn *ct)
 246 {
 247         return test_bit(IPS_DYING_BIT, &ct->status);
 248 }
 249
 250 extern unsigned int nf_conntrack_htable_size;
 251 extern int nf_conntrack_checksum;
 252 extern atomic_t nf_conntrack_count;
 253 extern int nf_conntrack_max;
 254
 255 DECLARE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
 256 #define NF_CT_STAT_INC(count) (__get_cpu_var(nf_conntrack_stat).count++)
 257
 258 /* no helper, no nat */
 259 #define NF_CT_F_BASIC   0
 260 /* for helper */
 261 #define NF_CT_F_HELP    1
 262 /* for nat. */
 263 #define NF_CT_F_NAT     2
 264 #define NF_CT_F_NUM     4
 265
 266 extern int
 267 nf_conntrack_register_cache(u_int32_t features, const char *name, size_t size);
 268 extern void
 269 nf_conntrack_unregister_cache(u_int32_t features);
 270
 271 /* valid combinations:
 272  * basic: nf_conn, nf_conn .. nf_conn_help
 273  * nat: nf_conn .. nf_conn_nat, nf_conn .. nf_conn_nat .. nf_conn help
 274  */
 275 #ifdef CONFIG_NF_NAT_NEEDED
 276 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
 277 {
 278         unsigned int offset = sizeof(struct nf_conn);
 279
 280         if (!(ct->features & NF_CT_F_NAT))
 281                 return NULL;
 282
 283         offset = ALIGN(offset, __alignof__(struct nf_conn_nat));
 284         return (struct nf_conn_nat *) ((void *)ct + offset);
 285 }
 286
 287 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 288 {
 289         unsigned int offset = sizeof(struct nf_conn);
 290
 291         if (!(ct->features & NF_CT_F_HELP))
 292                 return NULL;
 293         if (ct->features & NF_CT_F_NAT) {
 294                 offset = ALIGN(offset, __alignof__(struct nf_conn_nat));
 295                 offset += sizeof(struct nf_conn_nat);
 296         }
 297
 298         offset = ALIGN(offset, __alignof__(struct nf_conn_help));
 299         return (struct nf_conn_help *) ((void *)ct + offset);
 300 }
 301 #else /* No NAT */
 302 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 303 {
 304         unsigned int offset = sizeof(struct nf_conn);
 305
 306         if (!(ct->features & NF_CT_F_HELP))
 307                 return NULL;
 308
 309         offset = ALIGN(offset, __alignof__(struct nf_conn_help));
 310         return (struct nf_conn_help *) ((void *)ct + offset);
 311 }
 312 #endif /* CONFIG_NF_NAT_NEEDED */
 313 #endif /* __KERNEL__ */
 314 #endif /* _NF_CONNTRACK_H */