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_dccp.h>
  24 #include <linux/netfilter/nf_conntrack_sctp.h>
  25 #include <linux/netfilter/nf_conntrack_proto_gre.h>
  26 #include <net/netfilter/ipv4/nf_conntrack_icmp.h>
  27 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
  28
  29 #include <net/netfilter/nf_conntrack_tuple.h>
  30
  31 /* per conntrack: protocol private data */
  32 union nf_conntrack_proto {
  33         /* insert conntrack proto private data here */
  34         struct nf_ct_dccp dccp;
  35         struct ip_ct_sctp sctp;
  36         struct ip_ct_tcp tcp;
  37         struct ip_ct_icmp icmp;
  38         struct nf_ct_icmpv6 icmpv6;
  39         struct nf_ct_gre gre;
  40 };
  41
  42 union nf_conntrack_expect_proto {
  43         /* insert expect proto private data here */
  44 };
  45
  46 /* Add protocol helper include file here */
  47 #include <linux/netfilter/nf_conntrack_ftp.h>
  48 #include <linux/netfilter/nf_conntrack_pptp.h>
  49 #include <linux/netfilter/nf_conntrack_h323.h>
  50 #include <linux/netfilter/nf_conntrack_sane.h>
  51 #include <linux/netfilter/nf_conntrack_sip.h>
  52
  53 /* per conntrack: application helper private data */
  54 union nf_conntrack_help {
  55         /* insert conntrack helper private data (master) here */
  56         struct nf_ct_ftp_master ct_ftp_info;
  57         struct nf_ct_pptp_master ct_pptp_info;
  58         struct nf_ct_h323_master ct_h323_info;
  59         struct nf_ct_sane_master ct_sane_info;
  60         struct nf_ct_sip_master ct_sip_info;
  61 };
  62
  63 #include <linux/types.h>
  64 #include <linux/skbuff.h>
  65 #include <linux/timer.h>
  66
  67 #ifdef CONFIG_NETFILTER_DEBUG
  68 #define NF_CT_ASSERT(x)         WARN_ON(!(x))
  69 #else
  70 #define NF_CT_ASSERT(x)
  71 #endif
  72
  73 struct nf_conntrack_helper;
  74
  75 /* Must be kept in sync with the classes defined by helpers */
  76 #define NF_CT_MAX_EXPECT_CLASSES        3
  77
  78 /* nf_conn feature for connections that have a helper */
  79 struct nf_conn_help {
  80         /* Helper. if any */
  81         struct nf_conntrack_helper *helper;
  82
  83         union nf_conntrack_help help;
  84
  85         struct hlist_head expectations;
  86
  87         /* Current number of expected connections */
  88         u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
  89 };
  90
  91 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  92 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  93
  94 struct nf_conn
  95 {
  96         /* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
  97            plus 1 for any connection(s) we are `master' for */
  98         struct nf_conntrack ct_general;
  99
 100         /* XXX should I move this to the tail ? - Y.K */
 101         /* These are my tuples; original and reply */
 102         struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
 103
 104         /* Have we seen traffic both ways yet? (bitset) */
 105         unsigned long status;
 106
 107         /* If we were expected by an expectation, this will be it */
 108         struct nf_conn *master;
 109
 110         /* Timer function; drops refcnt when it goes off. */
 111         struct timer_list timeout;
 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         /* Extensions */
 125         struct nf_ct_ext *ext;
 126
 127         struct rcu_head rcu;
 128 };
 129
 130 static inline struct nf_conn *
 131 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 132 {
 133         return container_of(hash, struct nf_conn,
 134                             tuplehash[hash->tuple.dst.dir]);
 135 }
 136
 137 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
 138 {
 139         return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 140 }
 141
 142 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
 143 {
 144         return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
 145 }
 146
 147 /* get master conntrack via master expectation */
 148 #define master_ct(conntr) (conntr->master)
 149
 150 /* Alter reply tuple (maybe alter helper). */
 151 extern void
 152 nf_conntrack_alter_reply(struct nf_conn *ct,
 153                          const struct nf_conntrack_tuple *newreply);
 154
 155 /* Is this tuple taken? (ignoring any belonging to the given
 156    conntrack). */
 157 extern int
 158 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 159                          const struct nf_conn *ignored_conntrack);
 160
 161 /* Return conntrack_info and tuple hash for given skb. */
 162 static inline struct nf_conn *
 163 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 164 {
 165         *ctinfo = skb->nfctinfo;
 166         return (struct nf_conn *)skb->nfct;
 167 }
 168
 169 /* decrement reference count on a conntrack */
 170 static inline void nf_ct_put(struct nf_conn *ct)
 171 {
 172         NF_CT_ASSERT(ct);
 173         nf_conntrack_put(&ct->ct_general);
 174 }
 175
 176 /* Protocol module loading */
 177 extern int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 178 extern void nf_ct_l3proto_module_put(unsigned short l3proto);
 179
 180 extern struct hlist_head *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced);
 181 extern void nf_ct_free_hashtable(struct hlist_head *hash, int vmalloced,
 182                                  unsigned int size);
 183
 184 extern struct nf_conntrack_tuple_hash *
 185 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple);
 186
 187 extern void nf_conntrack_hash_insert(struct nf_conn *ct);
 188
 189 extern void nf_conntrack_flush(void);
 190
 191 extern bool nf_ct_get_tuplepr(const struct sk_buff *skb,
 192                               unsigned int nhoff, u_int16_t l3num,
 193                               struct nf_conntrack_tuple *tuple);
 194 extern bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 195                                  const struct nf_conntrack_tuple *orig);
 196
 197 extern void __nf_ct_refresh_acct(struct nf_conn *ct,
 198                                  enum ip_conntrack_info ctinfo,
 199                                  const struct sk_buff *skb,
 200                                  unsigned long extra_jiffies,
 201                                  int do_acct);
 202
 203 /* Refresh conntrack for this many jiffies and do accounting */
 204 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 205                                       enum ip_conntrack_info ctinfo,
 206                                       const struct sk_buff *skb,
 207                                       unsigned long extra_jiffies)
 208 {
 209         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 210 }
 211
 212 /* Refresh conntrack for this many jiffies */
 213 static inline void nf_ct_refresh(struct nf_conn *ct,
 214                                  const struct sk_buff *skb,
 215                                  unsigned long extra_jiffies)
 216 {
 217         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 218 }
 219
 220 extern bool __nf_ct_kill_acct(struct nf_conn *ct,
 221                               enum ip_conntrack_info ctinfo,
 222                               const struct sk_buff *skb,
 223                               int do_acct);
 224
 225 /* kill conntrack and do accounting */
 226 static inline bool nf_ct_kill_acct(struct nf_conn *ct,
 227                                    enum ip_conntrack_info ctinfo,
 228                                    const struct sk_buff *skb)
 229 {
 230         return __nf_ct_kill_acct(ct, ctinfo, skb, 1);
 231 }
 232
 233 /* kill conntrack without accounting */
 234 static inline bool nf_ct_kill(struct nf_conn *ct)
 235 {
 236         return __nf_ct_kill_acct(ct, 0, NULL, 0);
 237 }
 238
 239 /* These are for NAT.  Icky. */
 240 /* Update TCP window tracking data when NAT mangles the packet */
 241 extern void nf_conntrack_tcp_update(const struct sk_buff *skb,
 242                                     unsigned int dataoff,
 243                                     struct nf_conn *ct,
 244                                     int dir);
 245
 246 /* Fake conntrack entry for untracked connections */
 247 extern struct nf_conn nf_conntrack_untracked;
 248
 249 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 250 extern void
 251 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data);
 252 extern void nf_conntrack_free(struct nf_conn *ct);
 253 extern struct nf_conn *
 254 nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 255                    const struct nf_conntrack_tuple *repl,
 256                    gfp_t gfp);
 257
 258 /* It's confirmed if it is, or has been in the hash table. */
 259 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
 260 {
 261         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 262 }
 263
 264 static inline int nf_ct_is_dying(struct nf_conn *ct)
 265 {
 266         return test_bit(IPS_DYING_BIT, &ct->status);
 267 }
 268
 269 static inline int nf_ct_is_untracked(const struct sk_buff *skb)
 270 {
 271         return (skb->nfct == &nf_conntrack_untracked.ct_general);
 272 }
 273
 274 extern int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
 275 extern unsigned int nf_conntrack_htable_size;
 276 extern int nf_conntrack_checksum;
 277 extern atomic_t nf_conntrack_count;
 278 extern int nf_conntrack_max;
 279
 280 DECLARE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
 281 #define NF_CT_STAT_INC(count) (__get_cpu_var(nf_conntrack_stat).count++)
 282 #define NF_CT_STAT_INC_ATOMIC(count)                    \
 283 do {                                                    \
 284         local_bh_disable();                             \
 285         __get_cpu_var(nf_conntrack_stat).count++;       \
 286         local_bh_enable();                              \
 287 } while (0)
 288
 289 #endif /* __KERNEL__ */
 290 #endif /* _NF_CONNTRACK_H */