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 #include <linux/bitops.h>
  18 #include <linux/compiler.h>
  19 #include <linux/atomic.h>
  20
  21 #include <linux/netfilter/nf_conntrack_tcp.h>
  22 #include <linux/netfilter/nf_conntrack_dccp.h>
  23 #include <linux/netfilter/nf_conntrack_sctp.h>
  24 #include <linux/netfilter/nf_conntrack_proto_gre.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 nf_ct_dccp dccp;
  33         struct ip_ct_sctp sctp;
  34         struct ip_ct_tcp tcp;
  35         struct nf_ct_gre gre;
  36 };
  37
  38 union nf_conntrack_expect_proto {
  39         /* insert expect proto private data here */
  40 };
  41
  42 #include <linux/types.h>
  43 #include <linux/skbuff.h>
  44 #include <linux/timer.h>
  45
  46 #ifdef CONFIG_NETFILTER_DEBUG
  47 #define NF_CT_ASSERT(x)         WARN_ON(!(x))
  48 #else
  49 #define NF_CT_ASSERT(x)
  50 #endif
  51
  52 struct nf_conntrack_helper;
  53
  54 /* Must be kept in sync with the classes defined by helpers */
  55 #define NF_CT_MAX_EXPECT_CLASSES        4
  56
  57 /* nf_conn feature for connections that have a helper */
  58 struct nf_conn_help {
  59         /* Helper. if any */
  60         struct nf_conntrack_helper __rcu *helper;
  61
  62         struct hlist_head expectations;
  63
  64         /* Current number of expected connections */
  65         u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
  66
  67         /* private helper information. */
  68         char data[];
  69 };
  70
  71 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  72 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  73
  74 struct nf_conn {
  75         /* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
  76            plus 1 for any connection(s) we are `master' for */
  77         struct nf_conntrack ct_general;
  78
  79         spinlock_t lock;
  80
  81         /* XXX should I move this to the tail ? - Y.K */
  82         /* These are my tuples; original and reply */
  83         struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  84
  85         /* Have we seen traffic both ways yet? (bitset) */
  86         unsigned long status;
  87
  88         /* If we were expected by an expectation, this will be it */
  89         struct nf_conn *master;
  90
  91         /* Timer function; drops refcnt when it goes off. */
  92         struct timer_list timeout;
  93
  94 #if defined(CONFIG_NF_CONNTRACK_MARK)
  95         u_int32_t mark;
  96 #endif
  97
  98 #ifdef CONFIG_NF_CONNTRACK_SECMARK
  99         u_int32_t secmark;
 100 #endif
 101
 102         /* Extensions */
 103         struct nf_ct_ext *ext;
 104 #ifdef CONFIG_NET_NS
 105         struct net *ct_net;
 106 #endif
 107
 108         /* Storage reserved for other modules, must be the last member */
 109         union nf_conntrack_proto proto;
 110 };
 111
 112 static inline struct nf_conn *
 113 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 114 {
 115         return container_of(hash, struct nf_conn,
 116                             tuplehash[hash->tuple.dst.dir]);
 117 }
 118
 119 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
 120 {
 121         return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 122 }
 123
 124 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
 125 {
 126         return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
 127 }
 128
 129 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
 130
 131 /* get master conntrack via master expectation */
 132 #define master_ct(conntr) (conntr->master)
 133
 134 extern struct net init_net;
 135
 136 static inline struct net *nf_ct_net(const struct nf_conn *ct)
 137 {
 138         return read_pnet(&ct->ct_net);
 139 }
 140
 141 /* Alter reply tuple (maybe alter helper). */
 142 extern void
 143 nf_conntrack_alter_reply(struct nf_conn *ct,
 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 /*
 172  * Allocate a hashtable of hlist_head (if nulls == 0),
 173  * or hlist_nulls_head (if nulls == 1)
 174  */
 175 extern void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
 176
 177 extern void nf_ct_free_hashtable(void *hash, unsigned int size);
 178
 179 extern struct nf_conntrack_tuple_hash *
 180 __nf_conntrack_find(struct net *net, u16 zone,
 181                     const struct nf_conntrack_tuple *tuple);
 182
 183 extern int nf_conntrack_hash_check_insert(struct nf_conn *ct);
 184 extern void nf_ct_delete_from_lists(struct nf_conn *ct);
 185 extern void nf_ct_dying_timeout(struct nf_conn *ct);
 186
 187 extern void nf_conntrack_flush_report(struct net *net, u32 portid, int report);
 188
 189 extern bool nf_ct_get_tuplepr(const struct sk_buff *skb,
 190                               unsigned int nhoff, u_int16_t l3num,
 191                               struct nf_conntrack_tuple *tuple);
 192 extern bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 193                                  const struct nf_conntrack_tuple *orig);
 194
 195 extern void __nf_ct_refresh_acct(struct nf_conn *ct,
 196                                  enum ip_conntrack_info ctinfo,
 197                                  const struct sk_buff *skb,
 198                                  unsigned long extra_jiffies,
 199                                  int do_acct);
 200
 201 /* Refresh conntrack for this many jiffies and do accounting */
 202 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 203                                       enum ip_conntrack_info ctinfo,
 204                                       const struct sk_buff *skb,
 205                                       unsigned long extra_jiffies)
 206 {
 207         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 208 }
 209
 210 /* Refresh conntrack for this many jiffies */
 211 static inline void nf_ct_refresh(struct nf_conn *ct,
 212                                  const struct sk_buff *skb,
 213                                  unsigned long extra_jiffies)
 214 {
 215         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 216 }
 217
 218 extern bool __nf_ct_kill_acct(struct nf_conn *ct,
 219                               enum ip_conntrack_info ctinfo,
 220                               const struct sk_buff *skb,
 221                               int do_acct);
 222
 223 /* kill conntrack and do accounting */
 224 static inline bool nf_ct_kill_acct(struct nf_conn *ct,
 225                                    enum ip_conntrack_info ctinfo,
 226                                    const struct sk_buff *skb)
 227 {
 228         return __nf_ct_kill_acct(ct, ctinfo, skb, 1);
 229 }
 230
 231 /* kill conntrack without accounting */
 232 static inline bool nf_ct_kill(struct nf_conn *ct)
 233 {
 234         return __nf_ct_kill_acct(ct, 0, NULL, 0);
 235 }
 236
 237 /* These are for NAT.  Icky. */
 238 extern s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
 239                                enum ip_conntrack_dir dir,
 240                                u32 seq);
 241
 242 /* Fake conntrack entry for untracked connections */
 243 DECLARE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
 244 static inline struct nf_conn *nf_ct_untracked_get(void)
 245 {
 246         return &__raw_get_cpu_var(nf_conntrack_untracked);
 247 }
 248 extern void nf_ct_untracked_status_or(unsigned long bits);
 249
 250 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 251 extern void
 252 nf_ct_iterate_cleanup(struct net *net, int (*iter)(struct nf_conn *i, void *data), void *data);
 253 extern void nf_conntrack_free(struct nf_conn *ct);
 254 extern struct nf_conn *
 255 nf_conntrack_alloc(struct net *net, u16 zone,
 256                    const struct nf_conntrack_tuple *orig,
 257                    const struct nf_conntrack_tuple *repl,
 258                    gfp_t gfp);
 259
 260 static inline int nf_ct_is_template(const struct nf_conn *ct)
 261 {
 262         return test_bit(IPS_TEMPLATE_BIT, &ct->status);
 263 }
 264
 265 /* It's confirmed if it is, or has been in the hash table. */
 266 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
 267 {
 268         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 269 }
 270
 271 static inline int nf_ct_is_dying(struct nf_conn *ct)
 272 {
 273         return test_bit(IPS_DYING_BIT, &ct->status);
 274 }
 275
 276 static inline int nf_ct_is_untracked(const struct nf_conn *ct)
 277 {
 278         return test_bit(IPS_UNTRACKED_BIT, &ct->status);
 279 }
 280
 281 /* Packet is received from loopback */
 282 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 283 {
 284         return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 285 }
 286
 287 struct kernel_param;
 288
 289 extern int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
 290 extern unsigned int nf_conntrack_htable_size;
 291 extern unsigned int nf_conntrack_max;
 292 extern unsigned int nf_conntrack_hash_rnd;
 293 void init_nf_conntrack_hash_rnd(void);
 294
 295 #define NF_CT_STAT_INC(net, count)        __this_cpu_inc((net)->ct.stat->count)
 296 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
 297
 298 #define MODULE_ALIAS_NFCT_HELPER(helper) \
 299         MODULE_ALIAS("nfct-helper-" helper)
 300
 301 #endif /* _NF_CONNTRACK_H */