LXR linux/include/net/netfilter/nf

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Connection state tracking for netfilter.  This is separated from,
   4 * but required by, the (future) NAT layer; it can also be used by an iptables
   5 * extension.
   6 *
   7 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
   8 *      - generalize L3 protocol dependent part.
   9 *
  10 * Derived from include/linux/netfiter_ipv4/ip_conntrack.h
  11 */
  12
  13#ifndef _NF_CONNTRACK_H
  14#define _NF_CONNTRACK_H
  15
  16#include <linux/netfilter/nf_conntrack_common.h>
  17
  18#include <linux/bitops.h>
  19#include <linux/compiler.h>
  20#include <linux/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/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#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  48#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  49
  50struct nf_conn {
  51        /* Usage count in here is 1 for hash table, 1 per skb,
  52         * plus 1 for any connection(s) we are `master' for
  53         *
  54         * Hint, SKB address this struct and refcnt via skb->_nfct and
  55         * helpers nf_conntrack_get() and nf_conntrack_put().
  56         * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
  57         * beware nf_ct_get() is different and don't inc refcnt.
  58         */
  59        struct nf_conntrack ct_general;
  60
  61        spinlock_t      lock;
  62        u16             cpu;
  63
  64#ifdef CONFIG_NF_CONNTRACK_ZONES
  65        struct nf_conntrack_zone zone;
  66#endif
  67        /* XXX should I move this to the tail ? - Y.K */
  68        /* These are my tuples; original and reply */
  69        struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  70
  71        /* Have we seen traffic both ways yet? (bitset) */
  72        unsigned long status;
  73
  74        /* jiffies32 when this ct is considered dead */
  75        u32 timeout;
  76
  77        possible_net_t ct_net;
  78
  79#if IS_ENABLED(CONFIG_NF_NAT)
  80        struct hlist_node       nat_bysource;
  81#endif
  82        /* all members below initialized via memset */
  83        u8 __nfct_init_offset[0];
  84
  85        /* If we were expected by an expectation, this will be it */
  86        struct nf_conn *master;
  87
  88#if defined(CONFIG_NF_CONNTRACK_MARK)
  89        u_int32_t mark;
  90#endif
  91
  92#ifdef CONFIG_NF_CONNTRACK_SECMARK
  93        u_int32_t secmark;
  94#endif
  95
  96        /* Extensions */
  97        struct nf_ct_ext *ext;
  98
  99        /* Storage reserved for other modules, must be the last member */
 100        union nf_conntrack_proto proto;
 101};
 102
 103static inline struct nf_conn *
 104nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 105{
 106        return container_of(hash, struct nf_conn,
 107                            tuplehash[hash->tuple.dst.dir]);
 108}
 109
 110static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
 111{
 112        return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 113}
 114
 115static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
 116{
 117        return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
 118}
 119
 120#define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
 121
 122/* get master conntrack via master expectation */
 123#define master_ct(conntr) (conntr->master)
 124
 125extern struct net init_net;
 126
 127static inline struct net *nf_ct_net(const struct nf_conn *ct)
 128{
 129        return read_pnet(&ct->ct_net);
 130}
 131
 132/* Alter reply tuple (maybe alter helper). */
 133void nf_conntrack_alter_reply(struct nf_conn *ct,
 134                              const struct nf_conntrack_tuple *newreply);
 135
 136/* Is this tuple taken? (ignoring any belonging to the given
 137   conntrack). */
 138int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 139                             const struct nf_conn *ignored_conntrack);
 140
 141#define NFCT_INFOMASK   7UL
 142#define NFCT_PTRMASK    ~(NFCT_INFOMASK)
 143
 144/* Return conntrack_info and tuple hash for given skb. */
 145static inline struct nf_conn *
 146nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 147{
 148        *ctinfo = skb->_nfct & NFCT_INFOMASK;
 149
 150        return (struct nf_conn *)(skb->_nfct & NFCT_PTRMASK);
 151}
 152
 153/* decrement reference count on a conntrack */
 154static inline void nf_ct_put(struct nf_conn *ct)
 155{
 156        WARN_ON(!ct);
 157        nf_conntrack_put(&ct->ct_general);
 158}
 159
 160/* Protocol module loading */
 161int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 162void nf_ct_l3proto_module_put(unsigned short l3proto);
 163
 164/* load module; enable/disable conntrack in this namespace */
 165int nf_ct_netns_get(struct net *net, u8 nfproto);
 166void nf_ct_netns_put(struct net *net, u8 nfproto);
 167
 168/*
 169 * Allocate a hashtable of hlist_head (if nulls == 0),
 170 * or hlist_nulls_head (if nulls == 1)
 171 */
 172void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
 173
 174void nf_ct_free_hashtable(void *hash, unsigned int size);
 175
 176int nf_conntrack_hash_check_insert(struct nf_conn *ct);
 177bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
 178
 179bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 180                       u_int16_t l3num, struct net *net,
 181                       struct nf_conntrack_tuple *tuple);
 182bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 183                          const struct nf_conntrack_tuple *orig);
 184
 185void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 186                          const struct sk_buff *skb,
 187                          unsigned long extra_jiffies, int do_acct);
 188
 189/* Refresh conntrack for this many jiffies and do accounting */
 190static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 191                                      enum ip_conntrack_info ctinfo,
 192                                      const struct sk_buff *skb,
 193                                      unsigned long extra_jiffies)
 194{
 195        __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 196}
 197
 198/* Refresh conntrack for this many jiffies */
 199static inline void nf_ct_refresh(struct nf_conn *ct,
 200                                 const struct sk_buff *skb,
 201                                 unsigned long extra_jiffies)
 202{
 203        __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 204}
 205
 206/* kill conntrack and do accounting */
 207bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 208                     const struct sk_buff *skb);
 209
 210/* kill conntrack without accounting */
 211static inline bool nf_ct_kill(struct nf_conn *ct)
 212{
 213        return nf_ct_delete(ct, 0, 0);
 214}
 215
 216/* Set all unconfirmed conntrack as dying */
 217void nf_ct_unconfirmed_destroy(struct net *);
 218
 219/* Iterate over all conntracks: if iter returns true, it's deleted. */
 220void nf_ct_iterate_cleanup_net(struct net *net,
 221                               int (*iter)(struct nf_conn *i, void *data),
 222                               void *data, u32 portid, int report);
 223
 224/* also set unconfirmed conntracks as dying. Only use in module exit path. */
 225void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
 226                           void *data);
 227
 228struct nf_conntrack_zone;
 229
 230void nf_conntrack_free(struct nf_conn *ct);
 231struct nf_conn *nf_conntrack_alloc(struct net *net,
 232                                   const struct nf_conntrack_zone *zone,
 233                                   const struct nf_conntrack_tuple *orig,
 234                                   const struct nf_conntrack_tuple *repl,
 235                                   gfp_t gfp);
 236
 237static inline int nf_ct_is_template(const struct nf_conn *ct)
 238{
 239        return test_bit(IPS_TEMPLATE_BIT, &ct->status);
 240}
 241
 242/* It's confirmed if it is, or has been in the hash table. */
 243static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
 244{
 245        return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 246}
 247
 248static inline int nf_ct_is_dying(const struct nf_conn *ct)
 249{
 250        return test_bit(IPS_DYING_BIT, &ct->status);
 251}
 252
 253/* Packet is received from loopback */
 254static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 255{
 256        return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 257}
 258
 259#define nfct_time_stamp ((u32)(jiffies))
 260
 261/* jiffies until ct expires, 0 if already expired */
 262static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
 263{
 264        s32 timeout = ct->timeout - nfct_time_stamp;
 265
 266        return timeout > 0 ? timeout : 0;
 267}
 268
 269static inline bool nf_ct_is_expired(const struct nf_conn *ct)
 270{
 271        return (__s32)(ct->timeout - nfct_time_stamp) <= 0;
 272}
 273
 274/* use after obtaining a reference count */
 275static inline bool nf_ct_should_gc(const struct nf_conn *ct)
 276{
 277        return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
 278               !nf_ct_is_dying(ct);
 279}
 280
 281struct kernel_param;
 282
 283int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
 284int nf_conntrack_hash_resize(unsigned int hashsize);
 285
 286extern struct hlist_nulls_head *nf_conntrack_hash;
 287extern unsigned int nf_conntrack_htable_size;
 288extern seqcount_t nf_conntrack_generation;
 289extern unsigned int nf_conntrack_max;
 290
 291/* must be called with rcu read lock held */
 292static inline void
 293nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
 294{
 295        struct hlist_nulls_head *hptr;
 296        unsigned int sequence, hsz;
 297
 298        do {
 299                sequence = read_seqcount_begin(&nf_conntrack_generation);
 300                hsz = nf_conntrack_htable_size;
 301                hptr = nf_conntrack_hash;
 302        } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
 303
 304        *hash = hptr;
 305        *hsize = hsz;
 306}
 307
 308struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 309                                 const struct nf_conntrack_zone *zone,
 310                                 gfp_t flags);
 311void nf_ct_tmpl_free(struct nf_conn *tmpl);
 312
 313static inline void
 314nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
 315{
 316        skb->_nfct = (unsigned long)ct | info;
 317}
 318
 319#define NF_CT_STAT_INC(net, count)        __this_cpu_inc((net)->ct.stat->count)
 320#define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
 321#define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
 322
 323#define MODULE_ALIAS_NFCT_HELPER(helper) \
 324        MODULE_ALIAS("nfct-helper-" helper)
 325
 326#endif /* _NF_CONNTRACK_H */
 327