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
  44struct nf_conntrack_net {
  45        unsigned int users4;
  46        unsigned int users6;
  47};
  48
  49#include <linux/types.h>
  50#include <linux/skbuff.h>
  51
  52#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  53#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  54
  55struct nf_conn {
  56        /* Usage count in here is 1 for hash table, 1 per skb,
  57         * plus 1 for any connection(s) we are `master' for
  58         *
  59         * Hint, SKB address this struct and refcnt via skb->_nfct and
  60         * helpers nf_conntrack_get() and nf_conntrack_put().
  61         * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
  62         * beware nf_ct_get() is different and don't inc refcnt.
  63         */
  64        struct nf_conntrack ct_general;
  65
  66        spinlock_t      lock;
  67        u16             cpu;
  68
  69#ifdef CONFIG_NF_CONNTRACK_ZONES
  70        struct nf_conntrack_zone zone;
  71#endif
  72        /* XXX should I move this to the tail ? - Y.K */
  73        /* These are my tuples; original and reply */
  74        struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  75
  76        /* Have we seen traffic both ways yet? (bitset) */
  77        unsigned long status;
  78
  79        /* jiffies32 when this ct is considered dead */
  80        u32 timeout;
  81
  82        possible_net_t ct_net;
  83
  84#if IS_ENABLED(CONFIG_NF_NAT)
  85        struct hlist_node       nat_bysource;
  86#endif
  87        /* all members below initialized via memset */
  88        u8 __nfct_init_offset[0];
  89
  90        /* If we were expected by an expectation, this will be it */
  91        struct nf_conn *master;
  92
  93#if defined(CONFIG_NF_CONNTRACK_MARK)
  94        u_int32_t mark;
  95#endif
  96
  97#ifdef CONFIG_NF_CONNTRACK_SECMARK
  98        u_int32_t secmark;
  99#endif
 100
 101        /* Extensions */
 102        struct nf_ct_ext *ext;
 103
 104        /* Storage reserved for other modules, must be the last member */
 105        union nf_conntrack_proto proto;
 106};
 107
 108static inline struct nf_conn *
 109nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 110{
 111        return container_of(hash, struct nf_conn,
 112                            tuplehash[hash->tuple.dst.dir]);
 113}
 114
 115static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
 116{
 117        return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 118}
 119
 120static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
 121{
 122        return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
 123}
 124
 125#define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
 126
 127/* get master conntrack via master expectation */
 128#define master_ct(conntr) (conntr->master)
 129
 130extern struct net init_net;
 131
 132static inline struct net *nf_ct_net(const struct nf_conn *ct)
 133{
 134        return read_pnet(&ct->ct_net);
 135}
 136
 137/* Alter reply tuple (maybe alter helper). */
 138void nf_conntrack_alter_reply(struct nf_conn *ct,
 139                              const struct nf_conntrack_tuple *newreply);
 140
 141/* Is this tuple taken? (ignoring any belonging to the given
 142   conntrack). */
 143int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 144                             const struct nf_conn *ignored_conntrack);
 145
 146#define NFCT_INFOMASK   7UL
 147#define NFCT_PTRMASK    ~(NFCT_INFOMASK)
 148
 149/* Return conntrack_info and tuple hash for given skb. */
 150static inline struct nf_conn *
 151nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 152{
 153        *ctinfo = skb->_nfct & NFCT_INFOMASK;
 154
 155        return (struct nf_conn *)(skb->_nfct & NFCT_PTRMASK);
 156}
 157
 158/* decrement reference count on a conntrack */
 159static inline void nf_ct_put(struct nf_conn *ct)
 160{
 161        WARN_ON(!ct);
 162        nf_conntrack_put(&ct->ct_general);
 163}
 164
 165/* Protocol module loading */
 166int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 167void nf_ct_l3proto_module_put(unsigned short l3proto);
 168
 169/* load module; enable/disable conntrack in this namespace */
 170int nf_ct_netns_get(struct net *net, u8 nfproto);
 171void nf_ct_netns_put(struct net *net, u8 nfproto);
 172
 173/*
 174 * Allocate a hashtable of hlist_head (if nulls == 0),
 175 * or hlist_nulls_head (if nulls == 1)
 176 */
 177void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
 178
 179int nf_conntrack_hash_check_insert(struct nf_conn *ct);
 180bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
 181
 182bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 183                       u_int16_t l3num, struct net *net,
 184                       struct nf_conntrack_tuple *tuple);
 185bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 186                          const struct nf_conntrack_tuple *orig);
 187
 188void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 189                          const struct sk_buff *skb,
 190                          unsigned long extra_jiffies, int do_acct);
 191
 192/* Refresh conntrack for this many jiffies and do accounting */
 193static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 194                                      enum ip_conntrack_info ctinfo,
 195                                      const struct sk_buff *skb,
 196                                      unsigned long extra_jiffies)
 197{
 198        __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1);
 199}
 200
 201/* Refresh conntrack for this many jiffies */
 202static inline void nf_ct_refresh(struct nf_conn *ct,
 203                                 const struct sk_buff *skb,
 204                                 unsigned long extra_jiffies)
 205{
 206        __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 207}
 208
 209/* kill conntrack and do accounting */
 210bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 211                     const struct sk_buff *skb);
 212
 213/* kill conntrack without accounting */
 214static inline bool nf_ct_kill(struct nf_conn *ct)
 215{
 216        return nf_ct_delete(ct, 0, 0);
 217}
 218
 219/* Set all unconfirmed conntrack as dying */
 220void nf_ct_unconfirmed_destroy(struct net *);
 221
 222/* Iterate over all conntracks: if iter returns true, it's deleted. */
 223void nf_ct_iterate_cleanup_net(struct net *net,
 224                               int (*iter)(struct nf_conn *i, void *data),
 225                               void *data, u32 portid, int report);
 226
 227/* also set unconfirmed conntracks as dying. Only use in module exit path. */
 228void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
 229                           void *data);
 230
 231struct nf_conntrack_zone;
 232
 233void nf_conntrack_free(struct nf_conn *ct);
 234struct nf_conn *nf_conntrack_alloc(struct net *net,
 235                                   const struct nf_conntrack_zone *zone,
 236                                   const struct nf_conntrack_tuple *orig,
 237                                   const struct nf_conntrack_tuple *repl,
 238                                   gfp_t gfp);
 239
 240static inline int nf_ct_is_template(const struct nf_conn *ct)
 241{
 242        return test_bit(IPS_TEMPLATE_BIT, &ct->status);
 243}
 244
 245/* It's confirmed if it is, or has been in the hash table. */
 246static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
 247{
 248        return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 249}
 250
 251static inline int nf_ct_is_dying(const struct nf_conn *ct)
 252{
 253        return test_bit(IPS_DYING_BIT, &ct->status);
 254}
 255
 256/* Packet is received from loopback */
 257static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 258{
 259        return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 260}
 261
 262#define nfct_time_stamp ((u32)(jiffies))
 263
 264/* jiffies until ct expires, 0 if already expired */
 265static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
 266{
 267        s32 timeout = ct->timeout - nfct_time_stamp;
 268
 269        return timeout > 0 ? timeout : 0;
 270}
 271
 272static inline bool nf_ct_is_expired(const struct nf_conn *ct)
 273{
 274        return (__s32)(ct->timeout - nfct_time_stamp) <= 0;
 275}
 276
 277/* use after obtaining a reference count */
 278static inline bool nf_ct_should_gc(const struct nf_conn *ct)
 279{
 280        return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
 281               !nf_ct_is_dying(ct);
 282}
 283
 284struct kernel_param;
 285
 286int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
 287int nf_conntrack_hash_resize(unsigned int hashsize);
 288
 289extern struct hlist_nulls_head *nf_conntrack_hash;
 290extern unsigned int nf_conntrack_htable_size;
 291extern seqcount_t nf_conntrack_generation;
 292extern unsigned int nf_conntrack_max;
 293
 294/* must be called with rcu read lock held */
 295static inline void
 296nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
 297{
 298        struct hlist_nulls_head *hptr;
 299        unsigned int sequence, hsz;
 300
 301        do {
 302                sequence = read_seqcount_begin(&nf_conntrack_generation);
 303                hsz = nf_conntrack_htable_size;
 304                hptr = nf_conntrack_hash;
 305        } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
 306
 307        *hash = hptr;
 308        *hsize = hsz;
 309}
 310
 311struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 312                                 const struct nf_conntrack_zone *zone,
 313                                 gfp_t flags);
 314void nf_ct_tmpl_free(struct nf_conn *tmpl);
 315
 316static inline void
 317nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
 318{
 319        skb->_nfct = (unsigned long)ct | info;
 320}
 321
 322#define NF_CT_STAT_INC(net, count)        __this_cpu_inc((net)->ct.stat->count)
 323#define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
 324#define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))
 325
 326#define MODULE_ALIAS_NFCT_HELPER(helper) \
 327        MODULE_ALIAS("nfct-helper-" helper)
 328
 329#endif /* _NF_CONNTRACK_H */
 330