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