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 void nf_conntrack_alter_reply(struct nf_conn *ct,
 143                               const struct nf_conntrack_tuple *newreply);
 144
 145 /* Is this tuple taken? (ignoring any belonging to the given
 146    conntrack). */
 147 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 148                              const struct nf_conn *ignored_conntrack);
 149
 150 /* Return conntrack_info and tuple hash for given skb. */
 151 static inline struct nf_conn *
 152 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 153 {
 154         *ctinfo = skb->nfctinfo;
 155         return (struct nf_conn *)skb->nfct;
 156 }
 157
 158 /* decrement reference count on a conntrack */
 159 static inline void nf_ct_put(struct nf_conn *ct)
 160 {
 161         NF_CT_ASSERT(ct);
 162         nf_conntrack_put(&ct->ct_general);
 163 }
 164
 165 /* Protocol module loading */
 166 int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 167 void nf_ct_l3proto_module_put(unsigned short l3proto);
 168
 169 /*
 170  * Allocate a hashtable of hlist_head (if nulls == 0),
 171  * or hlist_nulls_head (if nulls == 1)
 172  */
 173 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
 174
 175 void nf_ct_free_hashtable(void *hash, unsigned int size);
 176
 177 struct nf_conntrack_tuple_hash *
 178 __nf_conntrack_find(struct net *net, u16 zone,
 179                     const struct nf_conntrack_tuple *tuple);
 180
 181 int nf_conntrack_hash_check_insert(struct nf_conn *ct);
 182 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
 183
 184 void nf_conntrack_flush_report(struct net *net, u32 portid, int report);
 185
 186 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 187                        u_int16_t l3num, struct nf_conntrack_tuple *tuple);
 188 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 189                           const struct nf_conntrack_tuple *orig);
 190
 191 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 192                           const struct sk_buff *skb,
 193                           unsigned long extra_jiffies, int do_acct);
 194
 195 /* Refresh conntrack for this many jiffies and do accounting */
 196 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 197                                       enum ip_conntrack_info ctinfo,
 198                                       const struct sk_buff *skb,
 199                                       unsigned long extra_jiffies)
 200 {
 201         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 202 }
 203
 204 /* Refresh conntrack for this many jiffies */
 205 static inline void nf_ct_refresh(struct nf_conn *ct,
 206                                  const struct sk_buff *skb,
 207                                  unsigned long extra_jiffies)
 208 {
 209         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 210 }
 211
 212 bool __nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 213                        const struct sk_buff *skb, int do_acct);
 214
 215 /* kill conntrack and do accounting */
 216 static inline bool nf_ct_kill_acct(struct nf_conn *ct,
 217                                    enum ip_conntrack_info ctinfo,
 218                                    const struct sk_buff *skb)
 219 {
 220         return __nf_ct_kill_acct(ct, ctinfo, skb, 1);
 221 }
 222
 223 /* kill conntrack without accounting */
 224 static inline bool nf_ct_kill(struct nf_conn *ct)
 225 {
 226         return __nf_ct_kill_acct(ct, 0, NULL, 0);
 227 }
 228
 229 /* These are for NAT.  Icky. */
 230 extern s32 (*nf_ct_nat_offset)(const struct nf_conn *ct,
 231                                enum ip_conntrack_dir dir,
 232                                u32 seq);
 233
 234 /* Fake conntrack entry for untracked connections */
 235 DECLARE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
 236 static inline struct nf_conn *nf_ct_untracked_get(void)
 237 {
 238         return &__raw_get_cpu_var(nf_conntrack_untracked);
 239 }
 240 void nf_ct_untracked_status_or(unsigned long bits);
 241
 242 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 243 void nf_ct_iterate_cleanup(struct net *net,
 244                            int (*iter)(struct nf_conn *i, void *data),
 245                            void *data, u32 portid, int report);
 246 void nf_conntrack_free(struct nf_conn *ct);
 247 struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
 248                                    const struct nf_conntrack_tuple *orig,
 249                                    const struct nf_conntrack_tuple *repl,
 250                                    gfp_t gfp);
 251
 252 static inline int nf_ct_is_template(const struct nf_conn *ct)
 253 {
 254         return test_bit(IPS_TEMPLATE_BIT, &ct->status);
 255 }
 256
 257 /* It's confirmed if it is, or has been in the hash table. */
 258 static inline int nf_ct_is_confirmed(struct nf_conn *ct)
 259 {
 260         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 261 }
 262
 263 static inline int nf_ct_is_dying(struct nf_conn *ct)
 264 {
 265         return test_bit(IPS_DYING_BIT, &ct->status);
 266 }
 267
 268 static inline int nf_ct_is_untracked(const struct nf_conn *ct)
 269 {
 270         return test_bit(IPS_UNTRACKED_BIT, &ct->status);
 271 }
 272
 273 /* Packet is received from loopback */
 274 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 275 {
 276         return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 277 }
 278
 279 struct kernel_param;
 280
 281 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
 282 extern unsigned int nf_conntrack_htable_size;
 283 extern unsigned int nf_conntrack_max;
 284 extern unsigned int nf_conntrack_hash_rnd;
 285 void init_nf_conntrack_hash_rnd(void);
 286
 287 #define NF_CT_STAT_INC(net, count)        __this_cpu_inc((net)->ct.stat->count)
 288 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
 289
 290 #define MODULE_ALIAS_NFCT_HELPER(helper) \
 291         MODULE_ALIAS("nfct-helper-" helper)
 292
 293 #endif /* _NF_CONNTRACK_H */