include/net/netfilter/nf_conntrack.h

   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/bitops.h>
  17 #include <linux/compiler.h>
  18
  19 #include <linux/netfilter/nf_conntrack_common.h>
  20 #include <linux/netfilter/nf_conntrack_tcp.h>
  21 #include <linux/netfilter/nf_conntrack_dccp.h>
  22 #include <linux/netfilter/nf_conntrack_sctp.h>
  23 #include <linux/netfilter/nf_conntrack_proto_gre.h>
  24
  25 #include <net/netfilter/nf_conntrack_tuple.h>
  26
  27 struct nf_ct_udp {
  28         unsigned long   stream_ts;
  29 };
  30
  31 /* per conntrack: protocol private data */
  32 union nf_conntrack_proto {
  33         /* insert conntrack proto private data here */
  34         struct nf_ct_dccp dccp;
  35         struct ip_ct_sctp sctp;
  36         struct ip_ct_tcp tcp;
  37         struct nf_ct_udp udp;
  38         struct nf_ct_gre gre;
  39         unsigned int tmpl_padto;
  40 };
  41
  42 union nf_conntrack_expect_proto {
  43         /* insert expect proto private data here */
  44 };
  45
  46 struct nf_conntrack_net {
  47         unsigned int users4;
  48         unsigned int users6;
  49         unsigned int users_bridge;
  50 };
  51
  52 #include <linux/types.h>
  53 #include <linux/skbuff.h>
  54
  55 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  56 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  57
  58 struct nf_conn {
  59         /* Usage count in here is 1 for hash table, 1 per skb,
  60          * plus 1 for any connection(s) we are `master' for
  61          *
  62          * Hint, SKB address this struct and refcnt via skb->_nfct and
  63          * helpers nf_conntrack_get() and nf_conntrack_put().
  64          * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
  65          * beware nf_ct_get() is different and don't inc refcnt.
  66          */
  67         struct nf_conntrack ct_general;
  68
  69         spinlock_t      lock;
  70         /* jiffies32 when this ct is considered dead */
  71         u32 timeout;
  72
  73 #ifdef CONFIG_NF_CONNTRACK_ZONES
  74         struct nf_conntrack_zone zone;
  75 #endif
  76         /* XXX should I move this to the tail ? - Y.K */
  77         /* These are my tuples; original and reply */
  78         struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
  79
  80         /* Have we seen traffic both ways yet? (bitset) */
  81         unsigned long status;
  82
  83         u16             cpu;
  84         possible_net_t ct_net;
  85
  86 #if IS_ENABLED(CONFIG_NF_NAT)
  87         struct hlist_node       nat_bysource;
  88 #endif
  89         /* all members below initialized via memset */
  90         struct { } __nfct_init_offset;
  91
  92         /* If we were expected by an expectation, this will be it */
  93         struct nf_conn *master;
  94
  95 #if defined(CONFIG_NF_CONNTRACK_MARK)
  96         u_int32_t mark;
  97 #endif
  98
  99 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 100         u_int32_t secmark;
 101 #endif
 102
 103         /* Extensions */
 104         struct nf_ct_ext *ext;
 105
 106         /* Storage reserved for other modules, must be the last member */
 107         union nf_conntrack_proto proto;
 108 };
 109
 110 static inline struct nf_conn *
 111 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash)
 112 {
 113         return container_of(hash, struct nf_conn,
 114                             tuplehash[hash->tuple.dst.dir]);
 115 }
 116
 117 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct)
 118 {
 119         return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 120 }
 121
 122 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct)
 123 {
 124         return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
 125 }
 126
 127 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)
 128
 129 /* get master conntrack via master expectation */
 130 #define master_ct(conntr) (conntr->master)
 131
 132 extern struct net init_net;
 133
 134 static inline struct net *nf_ct_net(const struct nf_conn *ct)
 135 {
 136         return read_pnet(&ct->ct_net);
 137 }
 138
 139 /* Alter reply tuple (maybe alter helper). */
 140 void nf_conntrack_alter_reply(struct nf_conn *ct,
 141                               const struct nf_conntrack_tuple *newreply);
 142
 143 /* Is this tuple taken? (ignoring any belonging to the given
 144    conntrack). */
 145 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 146                              const struct nf_conn *ignored_conntrack);
 147
 148 /* Return conntrack_info and tuple hash for given skb. */
 149 static inline struct nf_conn *
 150 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 151 {
 152         unsigned long nfct = skb_get_nfct(skb);
 153
 154         *ctinfo = nfct & NFCT_INFOMASK;
 155         return (struct nf_conn *)(nfct & NFCT_PTRMASK);
 156 }
 157
 158 /* decrement reference count on a conntrack */
 159 static 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 */
 166 int nf_ct_l3proto_try_module_get(unsigned short l3proto);
 167 void nf_ct_l3proto_module_put(unsigned short l3proto);
 168
 169 /* load module; enable/disable conntrack in this namespace */
 170 int nf_ct_netns_get(struct net *net, u8 nfproto);
 171 void 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  */
 177 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
 178
 179 int nf_conntrack_hash_check_insert(struct nf_conn *ct);
 180 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
 181
 182 bool 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);
 185
 186 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 187                           const struct sk_buff *skb,
 188                           u32 extra_jiffies, bool do_acct);
 189
 190 /* Refresh conntrack for this many jiffies and do accounting */
 191 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
 192                                       enum ip_conntrack_info ctinfo,
 193                                       const struct sk_buff *skb,
 194                                       u32 extra_jiffies)
 195 {
 196         __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true);
 197 }
 198
 199 /* Refresh conntrack for this many jiffies */
 200 static inline void nf_ct_refresh(struct nf_conn *ct,
 201                                  const struct sk_buff *skb,
 202                                  u32 extra_jiffies)
 203 {
 204         __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false);
 205 }
 206
 207 /* kill conntrack and do accounting */
 208 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 209                      const struct sk_buff *skb);
 210
 211 /* kill conntrack without accounting */
 212 static inline bool nf_ct_kill(struct nf_conn *ct)
 213 {
 214         return nf_ct_delete(ct, 0, 0);
 215 }
 216
 217 /* Set all unconfirmed conntrack as dying */
 218 void nf_ct_unconfirmed_destroy(struct net *);
 219
 220 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 221 void nf_ct_iterate_cleanup_net(struct net *net,
 222                                int (*iter)(struct nf_conn *i, void *data),
 223                                void *data, u32 portid, int report);
 224
 225 /* also set unconfirmed conntracks as dying. Only use in module exit path. */
 226 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data),
 227                            void *data);
 228
 229 struct nf_conntrack_zone;
 230
 231 void nf_conntrack_free(struct nf_conn *ct);
 232 struct nf_conn *nf_conntrack_alloc(struct net *net,
 233                                    const struct nf_conntrack_zone *zone,
 234                                    const struct nf_conntrack_tuple *orig,
 235                                    const struct nf_conntrack_tuple *repl,
 236                                    gfp_t gfp);
 237
 238 static inline int nf_ct_is_template(const struct nf_conn *ct)
 239 {
 240         return test_bit(IPS_TEMPLATE_BIT, &ct->status);
 241 }
 242
 243 /* It's confirmed if it is, or has been in the hash table. */
 244 static inline int nf_ct_is_confirmed(const struct nf_conn *ct)
 245 {
 246         return test_bit(IPS_CONFIRMED_BIT, &ct->status);
 247 }
 248
 249 static inline int nf_ct_is_dying(const struct nf_conn *ct)
 250 {
 251         return test_bit(IPS_DYING_BIT, &ct->status);
 252 }
 253
 254 /* Packet is received from loopback */
 255 static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 256 {
 257         return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 258 }
 259
 260 #define nfct_time_stamp ((u32)(jiffies))
 261
 262 /* jiffies until ct expires, 0 if already expired */
 263 static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
 264 {
 265         s32 timeout = ct->timeout - nfct_time_stamp;
 266
 267         return timeout > 0 ? timeout : 0;
 268 }
 269
 270 static inline bool nf_ct_is_expired(const struct nf_conn *ct)
 271 {
 272         return (__s32)(ct->timeout - nfct_time_stamp) <= 0;
 273 }
 274
 275 /* use after obtaining a reference count */
 276 static inline bool nf_ct_should_gc(const struct nf_conn *ct)
 277 {
 278         return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) &&
 279                !nf_ct_is_dying(ct);
 280 }
 281
 282 struct kernel_param;
 283
 284 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp);
 285 int nf_conntrack_hash_resize(unsigned int hashsize);
 286
 287 extern struct hlist_nulls_head *nf_conntrack_hash;
 288 extern unsigned int nf_conntrack_htable_size;
 289 extern seqcount_t nf_conntrack_generation;
 290 extern unsigned int nf_conntrack_max;
 291
 292 /* must be called with rcu read lock held */
 293 static inline void
 294 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
 295 {
 296         struct hlist_nulls_head *hptr;
 297         unsigned int sequence, hsz;
 298
 299         do {
 300                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 301                 hsz = nf_conntrack_htable_size;
 302                 hptr = nf_conntrack_hash;
 303         } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
 304
 305         *hash = hptr;
 306         *hsize = hsz;
 307 }
 308
 309 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 310                                  const struct nf_conntrack_zone *zone,
 311                                  gfp_t flags);
 312 void nf_ct_tmpl_free(struct nf_conn *tmpl);
 313
 314 u32 nf_ct_get_id(const struct nf_conn *ct);
 315
 316 static inline void
 317 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
 318 {
 319         skb_set_nfct(skb, (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 */