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_ecache { 47 struct delayed_work dwork; 48 spinlock_t dying_lock; 49 struct hlist_nulls_head dying_list; 50 }; 51 52 struct nf_conntrack_net { 53 /* only used when new connection is allocated: */ 54 atomic_t count; 55 unsigned int expect_count; 56 57 /* only used from work queues, configuration plane, and so on: */ 58 unsigned int users4; 59 unsigned int users6; 60 unsigned int users_bridge; 61 #ifdef CONFIG_SYSCTL 62 struct ctl_table_header *sysctl_header; 63 #endif 64 #ifdef CONFIG_NF_CONNTRACK_EVENTS 65 struct nf_conntrack_net_ecache ecache; 66 #endif 67 }; 68 69 #include <linux/types.h> 70 #include <linux/skbuff.h> 71 72 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> 73 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h> 74 75 struct nf_conn { 76 /* Usage count in here is 1 for hash table, 1 per skb, 77 * plus 1 for any connection(s) we are `master' for 78 * 79 * Hint, SKB address this struct and refcnt via skb->_nfct and 80 * helpers nf_conntrack_get() and nf_conntrack_put(). 81 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt, 82 * except that the latter uses internal indirection and does not 83 * result in a conntrack module dependency. 84 * beware nf_ct_get() is different and don't inc refcnt. 85 */ 86 struct nf_conntrack ct_general; 87 88 spinlock_t lock; 89 /* jiffies32 when this ct is considered dead */ 90 u32 timeout; 91 92 #ifdef CONFIG_NF_CONNTRACK_ZONES 93 struct nf_conntrack_zone zone; 94 #endif 95 /* XXX should I move this to the tail ? - Y.K */ 96 /* These are my tuples; original and reply */ 97 struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX]; 98 99 /* Have we seen traffic both ways yet? (bitset) */ 100 unsigned long status; 101 102 possible_net_t ct_net; 103 104 #if IS_ENABLED(CONFIG_NF_NAT) 105 struct hlist_node nat_bysource; 106 #endif 107 /* all members below initialized via memset */ 108 struct { } __nfct_init_offset; 109 110 /* If we were expected by an expectation, this will be it */ 111 struct nf_conn *master; 112 113 #if defined(CONFIG_NF_CONNTRACK_MARK) 114 u_int32_t mark; 115 #endif 116 117 #ifdef CONFIG_NF_CONNTRACK_SECMARK 118 u_int32_t secmark; 119 #endif 120 121 /* Extensions */ 122 struct nf_ct_ext *ext; 123 124 /* Storage reserved for other modules, must be the last member */ 125 union nf_conntrack_proto proto; 126 }; 127 128 static inline struct nf_conn * 129 nf_ct_to_nf_conn(const struct nf_conntrack *nfct) 130 { 131 return container_of(nfct, struct nf_conn, ct_general); 132 } 133 134 static inline struct nf_conn * 135 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash) 136 { 137 return container_of(hash, struct nf_conn, 138 tuplehash[hash->tuple.dst.dir]); 139 } 140 141 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct) 142 { 143 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num; 144 } 145 146 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct) 147 { 148 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum; 149 } 150 151 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple) 152 153 /* get master conntrack via master expectation */ 154 #define master_ct(conntr) (conntr->master) 155 156 extern struct net init_net; 157 158 static inline struct net *nf_ct_net(const struct nf_conn *ct) 159 { 160 return read_pnet(&ct->ct_net); 161 } 162 163 /* Alter reply tuple (maybe alter helper). */ 164 void nf_conntrack_alter_reply(struct nf_conn *ct, 165 const struct nf_conntrack_tuple *newreply); 166 167 /* Is this tuple taken? (ignoring any belonging to the given 168 conntrack). */ 169 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 170 const struct nf_conn *ignored_conntrack); 171 172 /* Return conntrack_info and tuple hash for given skb. */ 173 static inline struct nf_conn * 174 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo) 175 { 176 unsigned long nfct = skb_get_nfct(skb); 177 178 *ctinfo = nfct & NFCT_INFOMASK; 179 return (struct nf_conn *)(nfct & NFCT_PTRMASK); 180 } 181 182 void nf_ct_destroy(struct nf_conntrack *nfct); 183 184 void nf_conntrack_tcp_set_closing(struct nf_conn *ct); 185 186 /* decrement reference count on a conntrack */ 187 static inline void nf_ct_put(struct nf_conn *ct) 188 { 189 if (ct && refcount_dec_and_test(&ct->ct_general.use)) 190 nf_ct_destroy(&ct->ct_general); 191 } 192 193 /* Protocol module loading */ 194 int nf_ct_l3proto_try_module_get(unsigned short l3proto); 195 void nf_ct_l3proto_module_put(unsigned short l3proto); 196 197 /* load module; enable/disable conntrack in this namespace */ 198 int nf_ct_netns_get(struct net *net, u8 nfproto); 199 void nf_ct_netns_put(struct net *net, u8 nfproto); 200 201 /* 202 * Allocate a hashtable of hlist_head (if nulls == 0), 203 * or hlist_nulls_head (if nulls == 1) 204 */ 205 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls); 206 207 int nf_conntrack_hash_check_insert(struct nf_conn *ct); 208 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report); 209 210 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 211 u_int16_t l3num, struct net *net, 212 struct nf_conntrack_tuple *tuple); 213 214 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 215 const struct sk_buff *skb, 216 u32 extra_jiffies, bool do_acct); 217 218 /* Refresh conntrack for this many jiffies and do accounting */ 219 static inline void nf_ct_refresh_acct(struct nf_conn *ct, 220 enum ip_conntrack_info ctinfo, 221 const struct sk_buff *skb, 222 u32 extra_jiffies) 223 { 224 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true); 225 } 226 227 /* Refresh conntrack for this many jiffies */ 228 static inline void nf_ct_refresh(struct nf_conn *ct, 229 const struct sk_buff *skb, 230 u32 extra_jiffies) 231 { 232 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false); 233 } 234 235 /* kill conntrack and do accounting */ 236 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 237 const struct sk_buff *skb); 238 239 /* kill conntrack without accounting */ 240 static inline bool nf_ct_kill(struct nf_conn *ct) 241 { 242 return nf_ct_delete(ct, 0, 0); 243 } 244 245 struct nf_ct_iter_data { 246 struct net *net; 247 void *data; 248 u32 portid; 249 int report; 250 }; 251 252 /* Iterate over all conntracks: if iter returns true, it's deleted. */ 253 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data), 254 const struct nf_ct_iter_data *iter_data); 255 256 /* also set unconfirmed conntracks as dying. Only use in module exit path. */ 257 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), 258 void *data); 259 260 struct nf_conntrack_zone; 261 262 void nf_conntrack_free(struct nf_conn *ct); 263 struct nf_conn *nf_conntrack_alloc(struct net *net, 264 const struct nf_conntrack_zone *zone, 265 const struct nf_conntrack_tuple *orig, 266 const struct nf_conntrack_tuple *repl, 267 gfp_t gfp); 268 269 static inline int nf_ct_is_template(const struct nf_conn *ct) 270 { 271 return test_bit(IPS_TEMPLATE_BIT, &ct->status); 272 } 273 274 /* It's confirmed if it is, or has been in the hash table. */ 275 static inline int nf_ct_is_confirmed(const struct nf_conn *ct) 276 { 277 return test_bit(IPS_CONFIRMED_BIT, &ct->status); 278 } 279 280 static inline int nf_ct_is_dying(const struct nf_conn *ct) 281 { 282 return test_bit(IPS_DYING_BIT, &ct->status); 283 } 284 285 /* Packet is received from loopback */ 286 static inline bool nf_is_loopback_packet(const struct sk_buff *skb) 287 { 288 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK; 289 } 290 291 #define nfct_time_stamp ((u32)(jiffies)) 292 293 /* jiffies until ct expires, 0 if already expired */ 294 static inline unsigned long nf_ct_expires(const struct nf_conn *ct) 295 { 296 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp; 297 298 return max(timeout, 0); 299 } 300 301 static inline bool nf_ct_is_expired(const struct nf_conn *ct) 302 { 303 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0; 304 } 305 306 /* use after obtaining a reference count */ 307 static inline bool nf_ct_should_gc(const struct nf_conn *ct) 308 { 309 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) && 310 !nf_ct_is_dying(ct); 311 } 312 313 #define NF_CT_DAY (86400 * HZ) 314 315 /* Set an arbitrary timeout large enough not to ever expire, this save 316 * us a check for the IPS_OFFLOAD_BIT from the packet path via 317 * nf_ct_is_expired(). 318 */ 319 static inline void nf_ct_offload_timeout(struct nf_conn *ct) 320 { 321 if (nf_ct_expires(ct) < NF_CT_DAY / 2) 322 WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY); 323 } 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