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 <net/netns/generic.h> 20 #include <linux/netfilter/nf_conntrack_common.h> 21 #include <linux/netfilter/nf_conntrack_tcp.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 ip_ct_sctp sctp; 35 struct ip_ct_tcp tcp; 36 struct nf_ct_udp udp; 37 struct nf_ct_gre gre; 38 unsigned int tmpl_padto; 39 }; 40 41 union nf_conntrack_expect_proto { 42 /* insert expect proto private data here */ 43 }; 44 45 struct nf_conntrack_net_ecache { 46 struct delayed_work dwork; 47 spinlock_t dying_lock; 48 struct hlist_nulls_head dying_list; 49 }; 50 51 struct nf_conntrack_net { 52 /* only used when new connection is allocated: */ 53 atomic_t count; 54 unsigned int expect_count; 55 56 /* only used from work queues, configuration plane, and so on: */ 57 unsigned int users4; 58 unsigned int users6; 59 unsigned int users_bridge; 60 #ifdef CONFIG_SYSCTL 61 struct ctl_table_header *sysctl_header; 62 #endif 63 #ifdef CONFIG_NF_CONNTRACK_EVENTS 64 struct nf_conntrack_net_ecache ecache; 65 #endif 66 }; 67 68 #include <linux/types.h> 69 #include <linux/skbuff.h> 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, 1 per skb, 76 * plus 1 for any connection(s) we are `master' for 77 * 78 * Hint, SKB address this struct and refcnt via skb->_nfct and 79 * helpers nf_conntrack_get() and nf_conntrack_put(). 80 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt, 81 * except that the latter uses internal indirection and does not 82 * result in a conntrack module dependency. 83 * beware nf_ct_get() is different and don't inc refcnt. 84 */ 85 struct nf_conntrack ct_general; 86 87 spinlock_t lock; 88 /* jiffies32 when this ct is considered dead */ 89 u32 timeout; 90 91 #ifdef CONFIG_NF_CONNTRACK_ZONES 92 struct nf_conntrack_zone zone; 93 #endif 94 /* XXX should I move this to the tail ? - Y.K */ 95 /* These are my tuples; original and reply */ 96 struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX]; 97 98 /* Have we seen traffic both ways yet? (bitset) */ 99 unsigned long status; 100 101 possible_net_t ct_net; 102 103 #if IS_ENABLED(CONFIG_NF_NAT) 104 struct hlist_node nat_bysource; 105 #endif 106 /* all members below initialized via memset */ 107 struct { } __nfct_init_offset; 108 109 /* If we were expected by an expectation, this will be it */ 110 struct nf_conn *master; 111 112 #if defined(CONFIG_NF_CONNTRACK_MARK) 113 u_int32_t mark; 114 #endif 115 116 #ifdef CONFIG_NF_CONNTRACK_SECMARK 117 u_int32_t secmark; 118 #endif 119 120 /* Extensions */ 121 struct nf_ct_ext *ext; 122 123 /* Storage reserved for other modules, must be the last member */ 124 union nf_conntrack_proto proto; 125 }; 126 127 static inline struct nf_conn * 128 nf_ct_to_nf_conn(const struct nf_conntrack *nfct) 129 { 130 return container_of(nfct, struct nf_conn, ct_general); 131 } 132 133 static inline struct nf_conn * 134 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash) 135 { 136 return container_of(hash, struct nf_conn, 137 tuplehash[hash->tuple.dst.dir]); 138 } 139 140 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct) 141 { 142 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num; 143 } 144 145 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct) 146 { 147 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum; 148 } 149 150 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple) 151 152 /* get master conntrack via master expectation */ 153 #define master_ct(conntr) (conntr->master) 154 155 extern struct net init_net; 156 157 static inline struct net *nf_ct_net(const struct nf_conn *ct) 158 { 159 return read_pnet(&ct->ct_net); 160 } 161 162 /* Is this tuple taken? (ignoring any belonging to the given 163 conntrack). */ 164 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 165 const struct nf_conn *ignored_conntrack); 166 167 /* Return conntrack_info and tuple hash for given skb. */ 168 static inline struct nf_conn * 169 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo) 170 { 171 unsigned long nfct = skb_get_nfct(skb); 172 173 *ctinfo = nfct & NFCT_INFOMASK; 174 return (struct nf_conn *)(nfct & NFCT_PTRMASK); 175 } 176 177 void nf_ct_destroy(struct nf_conntrack *nfct); 178 179 void nf_conntrack_tcp_set_closing(struct nf_conn *ct); 180 181 /* decrement reference count on a conntrack */ 182 static inline void nf_ct_put(struct nf_conn *ct) 183 { 184 if (ct && refcount_dec_and_test(&ct->ct_general.use)) 185 nf_ct_destroy(&ct->ct_general); 186 } 187 188 /* load module; enable/disable conntrack in this namespace */ 189 int nf_ct_netns_get(struct net *net, u8 nfproto); 190 void nf_ct_netns_put(struct net *net, u8 nfproto); 191 192 /* 193 * Allocate a hashtable of hlist_head (if nulls == 0), 194 * or hlist_nulls_head (if nulls == 1) 195 */ 196 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls); 197 198 int nf_conntrack_hash_check_insert(struct nf_conn *ct); 199 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report); 200 201 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 202 u_int16_t l3num, struct net *net, 203 struct nf_conntrack_tuple *tuple); 204 205 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 206 u32 extra_jiffies, unsigned int bytes); 207 208 /* Refresh conntrack for this many jiffies and do accounting */ 209 static inline void nf_ct_refresh_acct(struct nf_conn *ct, 210 enum ip_conntrack_info ctinfo, 211 const struct sk_buff *skb, 212 u32 extra_jiffies) 213 { 214 __nf_ct_refresh_acct(ct, ctinfo, extra_jiffies, skb->len); 215 } 216 217 /* Refresh conntrack for this many jiffies */ 218 static inline void nf_ct_refresh(struct nf_conn *ct, 219 u32 extra_jiffies) 220 { 221 __nf_ct_refresh_acct(ct, 0, extra_jiffies, 0); 222 } 223 224 /* kill conntrack and do accounting */ 225 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 226 const struct sk_buff *skb); 227 228 /* kill conntrack without accounting */ 229 static inline bool nf_ct_kill(struct nf_conn *ct) 230 { 231 return nf_ct_delete(ct, 0, 0); 232 } 233 234 struct nf_ct_iter_data { 235 struct net *net; 236 void *data; 237 u32 portid; 238 int report; 239 }; 240 241 /* Iterate over all conntracks: if iter returns true, it's deleted. */ 242 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data), 243 const struct nf_ct_iter_data *iter_data); 244 245 /* also set unconfirmed conntracks as dying. Only use in module exit path. */ 246 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), 247 void *data); 248 249 struct nf_conntrack_zone; 250 251 void nf_conntrack_free(struct nf_conn *ct); 252 struct nf_conn *nf_conntrack_alloc(struct net *net, 253 const struct nf_conntrack_zone *zone, 254 const struct nf_conntrack_tuple *orig, 255 const struct nf_conntrack_tuple *repl, 256 gfp_t gfp); 257 258 static inline int nf_ct_is_template(const struct nf_conn *ct) 259 { 260 return test_bit(IPS_TEMPLATE_BIT, &ct->status); 261 } 262 263 /* It's confirmed if it is, or has been in the hash table. */ 264 static inline int nf_ct_is_confirmed(const struct nf_conn *ct) 265 { 266 return test_bit(IPS_CONFIRMED_BIT, &ct->status); 267 } 268 269 static inline int nf_ct_is_dying(const struct nf_conn *ct) 270 { 271 return test_bit(IPS_DYING_BIT, &ct->status); 272 } 273 274 /* Packet is received from loopback */ 275 static inline bool nf_is_loopback_packet(const struct sk_buff *skb) 276 { 277 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK; 278 } 279 280 static inline void nf_conntrack_alter_reply(struct nf_conn *ct, 281 const struct nf_conntrack_tuple *newreply) 282 { 283 /* Must be unconfirmed, so not in hash table yet */ 284 if (WARN_ON(nf_ct_is_confirmed(ct))) 285 return; 286 287 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 288 } 289 290 #define nfct_time_stamp ((u32)(jiffies)) 291 292 /* jiffies until ct expires, 0 if already expired */ 293 static inline unsigned long nf_ct_expires(const struct nf_conn *ct) 294 { 295 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp; 296 297 return max(timeout, 0); 298 } 299 300 static inline bool nf_ct_is_expired(const struct nf_conn *ct) 301 { 302 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0; 303 } 304 305 /* use after obtaining a reference count */ 306 static inline bool nf_ct_should_gc(const struct nf_conn *ct) 307 { 308 if (!nf_ct_is_confirmed(ct)) 309 return false; 310 311 /* load ct->timeout after is_confirmed() test. 312 * Pairs with __nf_conntrack_confirm() which: 313 * 1. Increases ct->timeout value 314 * 2. Inserts ct into rcu hlist 315 * 3. Sets the confirmed bit 316 * 4. Unlocks the hlist lock 317 */ 318 smp_acquire__after_ctrl_dep(); 319 320 return nf_ct_is_expired(ct) && !nf_ct_is_dying(ct); 321 } 322 323 #define NF_CT_DAY (86400 * HZ) 324 325 struct kernel_param; 326 327 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp); 328 int nf_conntrack_hash_resize(unsigned int hashsize); 329 330 extern struct hlist_nulls_head *nf_conntrack_hash; 331 extern unsigned int nf_conntrack_htable_size; 332 extern seqcount_spinlock_t nf_conntrack_generation; 333 extern unsigned int nf_conntrack_max; 334 335 /* must be called with rcu read lock held */ 336 static inline void 337 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize) 338 { 339 struct hlist_nulls_head *hptr; 340 unsigned int sequence, hsz; 341 342 do { 343 sequence = read_seqcount_begin(&nf_conntrack_generation); 344 hsz = nf_conntrack_htable_size; 345 hptr = nf_conntrack_hash; 346 } while (read_seqcount_retry(&nf_conntrack_generation, sequence)); 347 348 *hash = hptr; 349 *hsize = hsz; 350 } 351 352 struct nf_conn *nf_ct_tmpl_alloc(struct net *net, 353 const struct nf_conntrack_zone *zone, 354 gfp_t flags); 355 void nf_ct_tmpl_free(struct nf_conn *tmpl); 356 357 u32 nf_ct_get_id(const struct nf_conn *ct); 358 u32 nf_conntrack_count(const struct net *net); 359 360 static inline void 361 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info) 362 { 363 skb_set_nfct(skb, (unsigned long)ct | info); 364 } 365 366 extern unsigned int nf_conntrack_net_id; 367 368 static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net) 369 { 370 return net_generic(net, nf_conntrack_net_id); 371 } 372 373 int nf_ct_skb_network_trim(struct sk_buff *skb, int family); 374 int nf_ct_handle_fragments(struct net *net, struct sk_buff *skb, 375 u16 zone, u8 family, u8 *proto, u16 *mru); 376 377 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count) 378 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count) 379 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v)) 380 381 #define MODULE_ALIAS_NFCT_HELPER(helper) \ 382 MODULE_ALIAS("nfct-helper-" helper) 383 384 #endif /* _NF_CONNTRACK_H */ 385