LXR linux/include/net/netfilter/nf

   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#include <linux/rhashtable.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/ipv6/nf_conntrack_icmpv6.h>
  27
  28#include <net/netfilter/nf_conntrack_tuple.h>
  29
  30/* per conntrack: protocol private data */
  31union nf_conntrack_proto {
  32        /* insert conntrack proto private data here */
  33        struct nf_ct_dccp dccp;
  34        struct ip_ct_sctp sctp;
  35        struct ip_ct_tcp tcp;
  36        struct nf_ct_gre gre;
  37        unsigned int tmpl_padto;
  38};
  39
  40union nf_conntrack_expect_proto {
  41        /* insert expect proto private data here */
  42};
  43
  44#include <linux/types.h>
  45#include <linux/skbuff.h>
  46
  47#ifdef CONFIG_NETFILTER_DEBUG
  48#define NF_CT_ASSERT(x)         WARN_ON(!(x))
  49#else
  50#define NF_CT_ASSERT(x)
  51#endif
  52
  53#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  54#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  55
  56struct nf_conn {
  57        /* Usage count in here is 1 for hash table, 1 per skb,
  58         * plus 1 for any connection(s) we are `master' for
  59         *
  60         * Hint, SKB address this struct and refcnt via skb->_nfct and
  61         * helpers nf_conntrack_get() and nf_conntrack_put().
  62         * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
  63         * beware nf_ct_get() is different and don't inc refcnt.
  64         */
  65        struct nf_conntrack ct_general;
  66
  67        spinlock_t      lock;
  68        u16             cpu;
  69
  70#ifdef CONFIG_NF_CONNTRACK_ZONES
  71        struct nf_conntrack_zone zone;
  72#endif
  73        /* XXX should I move this to the tail ? - Y.K */
  74        /* These are my tuples; original and reply */
  75        struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  76
  77        /* Have we seen traffic both ways yet? (bitset) */
  78        unsigned long status;
  79
  80        /* jiffies32 when this ct is considered dead */
  81        u32 timeout;
  82
  83        possible_net_t ct_net;
  84
  85#if IS_ENABLED(CONFIG_NF_NAT)
  86        struct rhlist_head nat_bysource;
  87#endif
  88        /* all members below initialized via memset */
  89        u8 __nfct_init_offset[0];
  90
  91        /* If we were expected by an expectation, this will be it */
  92        struct nf_conn *master;
  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
 105        /* Storage reserved for other modules, must be the last member */
 106        union nf_conntrack_proto proto;
 107};
 108
 109static inline struct nf_conn *
 110nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 111{
 112        return container_of(hash, struct nf_conn,
 113                            tuplehash[hash->tuple.dst.dir]);
 114}
 115
 116static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
 117{
 118        return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 119}
 120
 121static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
 122{
 123        return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
 124}
 125
 126#define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
 127
 128/* get master conntrack via master expectation */
 129#define master_ct(conntr) (conntr->master)
 130
 131extern struct net init_net;
 132
 133static inline struct net *nf_ct_net(const struct nf_conn *ct)
 134{
 135        return read_pnet(&ct->ct_net);
 136}
 137
 138/* Alter reply tuple (maybe alter helper). */
 139void nf_conntrack_alter_reply(struct nf_conn *ct,
 140                              const struct nf_conntrack_tuple *newreply);
 141
 142/* Is this tuple taken? (ignoring any belonging to the given
 143   conntrack). */
 144int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 145                             const struct nf_conn *ignored_conntrack);
 146
 147#define NFCT_INFOMASK   7UL
 148#define NFCT_PTRMASK    ~(NFCT_INFOMASK)
 149
 150/* Return conntrack_info and tuple hash for given skb. */
 151static inline struct nf_conn *
 152nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 153{
 154        *ctinfo = skb->_nfct & NFCT_INFOMASK;
 155
 156        return (struct nf_conn *)(skb->_nfct & NFCT_PTRMASK);
 157}
 158
 159/* decrement reference count on a conntrack */
 160static inline void nf_ct_put(struct nf_conn *ct)
 161{
 162        NF_CT_ASSERT(ct);
 163        nf_conntrack_put(&ct->ct_general);
 164}
 165
 166/* Protocol module loading */
 167int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 168void nf_ct_l3proto_module_put(unsigned short l3proto);
 169
 170/* load module; enable/disable conntrack in this namespace */
 171int nf_ct_netns_get(struct net *net, u8 nfproto);
 172void nf_ct_netns_put(struct net *net, u8 nfproto);
 173
 174/*
 175 * Allocate a hashtable of hlist_head (if nulls == 0),
 176 * or hlist_nulls_head (if nulls == 1)
 177 */
 178void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
 179
 180void nf_ct_free_hashtable(void *hash, unsigned int size);
 181
 182int nf_conntrack_hash_check_insert(struct nf_conn *ct);
 183bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
 184
 185bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 186                       u_int16_t l3num, struct net *net,
 187                       struct nf_conntrack_tuple *tuple);
 188bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 189                          const struct nf_conntrack_tuple *orig);
 190
 191void __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 */
 196static 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 */
 205static 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/* kill conntrack and do accounting */
 213bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 214                     const struct sk_buff *skb);
 215
 216/* kill conntrack without accounting */
 217static inline bool nf_ct_kill(struct nf_conn *ct)
 218{
 219        return nf_ct_delete(ct, 0, 0);
 220}
 221
 222/* These are for NAT.  Icky. */
 223extern s32 (*nf_ct_nat_offset)(const struct nf_conn *ct,
 224                               enum ip_conntrack_dir dir,
 225                               u32 seq);
 226
 227/* Iterate over all conntracks: if iter returns true, it's deleted. */
 228void nf_ct_iterate_cleanup(struct net *net,
 229                           int (*iter)(struct nf_conn *i, void *data),
 230                           void *data, u32 portid, int report);
 231
 232struct nf_conntrack_zone;
 233
 234void nf_conntrack_free(struct nf_conn *ct);
 235struct nf_conn *nf_conntrack_alloc(struct net *net,
 236                                   const struct nf_conntrack_zone *zone,
 237                                   const struct nf_conntrack_tuple *orig,
 238                                   const struct nf_conntrack_tuple *repl,
 239                                   gfp_t gfp);
 240
 241static inline int nf_ct_is_template(const struct nf_conn *ct)
 242{
 243        return test_bit(IPS_TEMPLATE_BIT, &ct->status);
 244}
 245
 246/* It's confirmed if it is, or has been in the hash table. */
 247static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
 248{
 249        return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 250}
 251
 252static inline int nf_ct_is_dying(const struct nf_conn *ct)
 253{
 254        return test_bit(IPS_DYING_BIT, &ct->status);
 255}
 256
 257/* Packet is received from loopback */
 258static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 259{
 260        return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 261}
 262
 263#define nfct_time_stamp ((u32)(jiffies))
 264
 265/* jiffies until ct expires, 0 if already expired */
 266static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
 267{
 268        s32 timeout = ct->timeout - nfct_time_stamp;
 269
 270        return timeout > 0 ? timeout : 0;
 271}
 272
 273static inline bool nf_ct_is_expired(const struct nf_conn *ct)
 274{
 275        return (__s32)(ct->timeout - nfct_time_stamp) <= 0;
 276}
 277
 278/* use after obtaining a reference count */
 279static inline bool nf_ct_should_gc(const struct nf_conn *ct)
 280{
 281        return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
 282               !nf_ct_is_dying(ct);
 283}
 284
 285struct kernel_param;
 286
 287int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
 288int nf_conntrack_hash_resize(unsigned int hashsize);
 289
 290extern struct hlist_nulls_head *nf_conntrack_hash;
 291extern unsigned int nf_conntrack_htable_size;
 292extern seqcount_t nf_conntrack_generation;
 293extern unsigned int nf_conntrack_max;
 294
 295/* must be called with rcu read lock held */
 296static inline void
 297nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
 298{
 299        struct hlist_nulls_head *hptr;
 300        unsigned int sequence, hsz;
 301
 302        do {
 303                sequence = read_seqcount_begin(&nf_conntrack_generation);
 304                hsz = nf_conntrack_htable_size;
 305                hptr = nf_conntrack_hash;
 306        } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
 307
 308        *hash = hptr;
 309        *hsize = hsz;
 310}
 311
 312struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 313                                 const struct nf_conntrack_zone *zone,
 314                                 gfp_t flags);
 315void nf_ct_tmpl_free(struct nf_conn *tmpl);
 316
 317static inline void
 318nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
 319{
 320        skb->_nfct = (unsigned long)ct | info;
 321}
 322
 323#define NF_CT_STAT_INC(net, count)        __this_cpu_inc((net)->ct.stat->count)
 324#define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
 325#define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
 326
 327#define MODULE_ALIAS_NFCT_HELPER(helper) \
 328        MODULE_ALIAS("nfct-helper-" helper)
 329
 330#endif /* _NF_CONNTRACK_H */
 331