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          *
  78          * Hint, SKB address this struct and refcnt via skb->nfct and
  79          * helpers nf_conntrack_get() and nf_conntrack_put().
  80          * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
  81          * beware nf_ct_get() is different and don't inc refcnt.
  82          */
  83         struct nf_conntrack ct_general;
  84
  85         spinlock_t      lock;
  86         u16             cpu;
  87
  88 #ifdef CONFIG_NF_CONNTRACK_ZONES
  89         struct nf_conntrack_zone zone;
  90 #endif
  91         /* XXX should I move this to the tail ? - Y.K */
  92         /* These are my tuples; original and reply */
  93         struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  94
  95         /* Have we seen traffic both ways yet? (bitset) */
  96         unsigned long status;
  97
  98         /* Timer function; drops refcnt when it goes off. */
  99         struct timer_list timeout;
 100
 101         possible_net_t ct_net;
 102
 103         /* all members below initialized via memset */
 104         u8 __nfct_init_offset[0];
 105
 106         /* If we were expected by an expectation, this will be it */
 107         struct nf_conn *master;
 108
 109 #if defined(CONFIG_NF_CONNTRACK_MARK)
 110         u_int32_t mark;
 111 #endif
 112
 113 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 114         u_int32_t secmark;
 115 #endif
 116
 117         /* Extensions */
 118         struct nf_ct_ext *ext;
 119
 120         /* Storage reserved for other modules, must be the last member */
 121         union nf_conntrack_proto proto;
 122 };
 123
 124 static inline struct nf_conn *
 125 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 126 {
 127         return container_of(hash, struct nf_conn,
 128                             tuplehash[hash->tuple.dst.dir]);
 129 }
 130
 131 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
 132 {
 133         return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 134 }
 135
 136 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
 137 {
 138         return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
 139 }
 140
 141 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
 142
 143 /* get master conntrack via master expectation */
 144 #define master_ct(conntr) (conntr->master)
 145
 146 extern struct net init_net;
 147
 148 static inline struct net *nf_ct_net(const struct nf_conn *ct)
 149 {
 150         return read_pnet(&ct->ct_net);
 151 }
 152
 153 /* Alter reply tuple (maybe alter helper). */
 154 void nf_conntrack_alter_reply(struct nf_conn *ct,
 155                               const struct nf_conntrack_tuple *newreply);
 156
 157 /* Is this tuple taken? (ignoring any belonging to the given
 158    conntrack). */
 159 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 160                              const struct nf_conn *ignored_conntrack);
 161
 162 /* Return conntrack_info and tuple hash for given skb. */
 163 static inline struct nf_conn *
 164 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 165 {
 166         *ctinfo = skb->nfctinfo;
 167         return (struct nf_conn *)skb->nfct;
 168 }
 169
 170 /* decrement reference count on a conntrack */
 171 static inline void nf_ct_put(struct nf_conn *ct)
 172 {
 173         NF_CT_ASSERT(ct);
 174         nf_conntrack_put(&ct->ct_general);
 175 }
 176
 177 /* Protocol module loading */
 178 int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 179 void nf_ct_l3proto_module_put(unsigned short l3proto);
 180
 181 /*
 182  * Allocate a hashtable of hlist_head (if nulls == 0),
 183  * or hlist_nulls_head (if nulls == 1)
 184  */
 185 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
 186
 187 void nf_ct_free_hashtable(void *hash, unsigned int size);
 188
 189 int nf_conntrack_hash_check_insert(struct nf_conn *ct);
 190 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
 191
 192 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 193                        u_int16_t l3num, struct net *net,
 194                        struct nf_conntrack_tuple *tuple);
 195 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 196                           const struct nf_conntrack_tuple *orig);
 197
 198 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 199                           const struct sk_buff *skb,
 200                           unsigned long extra_jiffies, int do_acct);
 201
 202 /* Refresh conntrack for this many jiffies and do accounting */
 203 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 204                                       enum ip_conntrack_info ctinfo,
 205                                       const struct sk_buff *skb,
 206                                       unsigned long extra_jiffies)
 207 {
 208         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 209 }
 210
 211 /* Refresh conntrack for this many jiffies */
 212 static inline void nf_ct_refresh(struct nf_conn *ct,
 213                                  const struct sk_buff *skb,
 214                                  unsigned long extra_jiffies)
 215 {
 216         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 217 }
 218
 219 bool __nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 220                        const struct sk_buff *skb, int do_acct);
 221
 222 /* kill conntrack and do accounting */
 223 static inline bool nf_ct_kill_acct(struct nf_conn *ct,
 224                                    enum ip_conntrack_info ctinfo,
 225                                    const struct sk_buff *skb)
 226 {
 227         return __nf_ct_kill_acct(ct, ctinfo, skb, 1);
 228 }
 229
 230 /* kill conntrack without accounting */
 231 static inline bool nf_ct_kill(struct nf_conn *ct)
 232 {
 233         return __nf_ct_kill_acct(ct, 0, NULL, 0);
 234 }
 235
 236 /* These are for NAT.  Icky. */
 237 extern s32 (*nf_ct_nat_offset)(const struct nf_conn *ct,
 238                                enum ip_conntrack_dir dir,
 239                                u32 seq);
 240
 241 /* Fake conntrack entry for untracked connections */
 242 DECLARE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
 243 static inline struct nf_conn *nf_ct_untracked_get(void)
 244 {
 245         return raw_cpu_ptr(&nf_conntrack_untracked);
 246 }
 247 void nf_ct_untracked_status_or(unsigned long bits);
 248
 249 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 250 void nf_ct_iterate_cleanup(struct net *net,
 251                            int (*iter)(struct nf_conn *i, void *data),
 252                            void *data, u32 portid, int report);
 253
 254 struct nf_conntrack_zone;
 255
 256 void nf_conntrack_free(struct nf_conn *ct);
 257 struct nf_conn *nf_conntrack_alloc(struct net *net,
 258                                    const struct nf_conntrack_zone *zone,
 259                                    const struct nf_conntrack_tuple *orig,
 260                                    const struct nf_conntrack_tuple *repl,
 261                                    gfp_t gfp);
 262
 263 static inline int nf_ct_is_template(const struct nf_conn *ct)
 264 {
 265         return test_bit(IPS_TEMPLATE_BIT, &ct->status);
 266 }
 267
 268 /* It's confirmed if it is, or has been in the hash table. */
 269 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
 270 {
 271         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 272 }
 273
 274 static inline int nf_ct_is_dying(struct nf_conn *ct)
 275 {
 276         return test_bit(IPS_DYING_BIT, &ct->status);
 277 }
 278
 279 static inline int nf_ct_is_untracked(const struct nf_conn *ct)
 280 {
 281         return test_bit(IPS_UNTRACKED_BIT, &ct->status);
 282 }
 283
 284 /* Packet is received from loopback */
 285 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 286 {
 287         return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 288 }
 289
 290 struct kernel_param;
 291
 292 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
 293 extern unsigned int nf_conntrack_htable_size;
 294 extern unsigned int nf_conntrack_max;
 295
 296 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 297                                  const struct nf_conntrack_zone *zone,
 298                                  gfp_t flags);
 299 void nf_ct_tmpl_free(struct nf_conn *tmpl);
 300
 301 #define NF_CT_STAT_INC(net, count)        __this_cpu_inc((net)->ct.stat->count)
 302 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
 303
 304 #define MODULE_ALIAS_NFCT_HELPER(helper) \
 305         MODULE_ALIAS("nfct-helper-" helper)
 306
 307 #endif /* _NF_CONNTRACK_H */