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_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash) 130 { 131 return container_of(hash, struct nf_conn, 132 tuplehash[hash->tuple.dst.dir]); 133 } 134 135 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct) 136 { 137 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num; 138 } 139 140 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct) 141 { 142 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum; 143 } 144 145 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple) 146 147 /* get master conntrack via master expectation */ 148 #define master_ct(conntr) (conntr->master) 149 150 extern struct net init_net; 151 152 static inline struct net *nf_ct_net(const struct nf_conn *ct) 153 { 154 return read_pnet(&ct->ct_net); 155 } 156 157 /* Alter reply tuple (maybe alter helper). */ 158 void nf_conntrack_alter_reply(struct nf_conn *ct, 159 const struct nf_conntrack_tuple *newreply); 160 161 /* Is this tuple taken? (ignoring any belonging to the given 162 conntrack). */ 163 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 164 const struct nf_conn *ignored_conntrack); 165 166 /* Return conntrack_info and tuple hash for given skb. */ 167 static inline struct nf_conn * 168 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo) 169 { 170 unsigned long nfct = skb_get_nfct(skb); 171 172 *ctinfo = nfct & NFCT_INFOMASK; 173 return (struct nf_conn *)(nfct & NFCT_PTRMASK); 174 } 175 176 void nf_ct_destroy(struct nf_conntrack *nfct); 177 178 /* decrement reference count on a conntrack */ 179 static inline void nf_ct_put(struct nf_conn *ct) 180 { 181 if (ct && refcount_dec_and_test(&ct->ct_general.use)) 182 nf_ct_destroy(&ct->ct_general); 183 } 184 185 /* Protocol module loading */ 186 int nf_ct_l3proto_try_module_get(unsigned short l3proto); 187 void nf_ct_l3proto_module_put(unsigned short l3proto); 188 189 /* load module; enable/disable conntrack in this namespace */ 190 int nf_ct_netns_get(struct net *net, u8 nfproto); 191 void nf_ct_netns_put(struct net *net, u8 nfproto); 192 193 /* 194 * Allocate a hashtable of hlist_head (if nulls == 0), 195 * or hlist_nulls_head (if nulls == 1) 196 */ 197 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls); 198 199 int nf_conntrack_hash_check_insert(struct nf_conn *ct); 200 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report); 201 202 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 203 u_int16_t l3num, struct net *net, 204 struct nf_conntrack_tuple *tuple); 205 206 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 207 const struct sk_buff *skb, 208 u32 extra_jiffies, bool do_acct); 209 210 /* Refresh conntrack for this many jiffies and do accounting */ 211 static inline void nf_ct_refresh_acct(struct nf_conn *ct, 212 enum ip_conntrack_info ctinfo, 213 const struct sk_buff *skb, 214 u32 extra_jiffies) 215 { 216 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true); 217 } 218 219 /* Refresh conntrack for this many jiffies */ 220 static inline void nf_ct_refresh(struct nf_conn *ct, 221 const struct sk_buff *skb, 222 u32 extra_jiffies) 223 { 224 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false); 225 } 226 227 /* kill conntrack and do accounting */ 228 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 229 const struct sk_buff *skb); 230 231 /* kill conntrack without accounting */ 232 static inline bool nf_ct_kill(struct nf_conn *ct) 233 { 234 return nf_ct_delete(ct, 0, 0); 235 } 236 237 struct nf_ct_iter_data { 238 struct net *net; 239 void *data; 240 u32 portid; 241 int report; 242 }; 243 244 /* Iterate over all conntracks: if iter returns true, it's deleted. */ 245 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data), 246 const struct nf_ct_iter_data *iter_data); 247 248 /* also set unconfirmed conntracks as dying. Only use in module exit path. */ 249 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), 250 void *data); 251 252 struct nf_conntrack_zone; 253 254 void nf_conntrack_free(struct nf_conn *ct); 255 struct nf_conn *nf_conntrack_alloc(struct net *net, 256 const struct nf_conntrack_zone *zone, 257 const struct nf_conntrack_tuple *orig, 258 const struct nf_conntrack_tuple *repl, 259 gfp_t gfp); 260 261 static inline int nf_ct_is_template(const struct nf_conn *ct) 262 { 263 return test_bit(IPS_TEMPLATE_BIT, &ct->status); 264 } 265 266 /* It's confirmed if it is, or has been in the hash table. */ 267 static inline int nf_ct_is_confirmed(const struct nf_conn *ct) 268 { 269 return test_bit(IPS_CONFIRMED_BIT, &ct->status); 270 } 271 272 static inline int nf_ct_is_dying(const struct nf_conn *ct) 273 { 274 return test_bit(IPS_DYING_BIT, &ct->status); 275 } 276 277 /* Packet is received from loopback */ 278 static inline bool nf_is_loopback_packet(const struct sk_buff *skb) 279 { 280 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK; 281 } 282 283 #define nfct_time_stamp ((u32)(jiffies)) 284 285 /* jiffies until ct expires, 0 if already expired */ 286 static inline unsigned long nf_ct_expires(const struct nf_conn *ct) 287 { 288 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp; 289 290 return max(timeout, 0); 291 } 292 293 static inline bool nf_ct_is_expired(const struct nf_conn *ct) 294 { 295 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0; 296 } 297 298 /* use after obtaining a reference count */ 299 static inline bool nf_ct_should_gc(const struct nf_conn *ct) 300 { 301 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) && 302 !nf_ct_is_dying(ct); 303 } 304 305 #define NF_CT_DAY (86400 * HZ) 306 307 /* Set an arbitrary timeout large enough not to ever expire, this save 308 * us a check for the IPS_OFFLOAD_BIT from the packet path via 309 * nf_ct_is_expired(). 310 */ 311 static inline void nf_ct_offload_timeout(struct nf_conn *ct) 312 { 313 if (nf_ct_expires(ct) < NF_CT_DAY / 2) 314 WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY); 315 } 316 317 struct kernel_param; 318 319 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp); 320 int nf_conntrack_hash_resize(unsigned int hashsize); 321 322 extern struct hlist_nulls_head *nf_conntrack_hash; 323 extern unsigned int nf_conntrack_htable_size; 324 extern seqcount_spinlock_t nf_conntrack_generation; 325 extern unsigned int nf_conntrack_max; 326 327 /* must be called with rcu read lock held */ 328 static inline void 329 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize) 330 { 331 struct hlist_nulls_head *hptr; 332 unsigned int sequence, hsz; 333 334 do { 335 sequence = read_seqcount_begin(&nf_conntrack_generation); 336 hsz = nf_conntrack_htable_size; 337 hptr = nf_conntrack_hash; 338 } while (read_seqcount_retry(&nf_conntrack_generation, sequence)); 339 340 *hash = hptr; 341 *hsize = hsz; 342 } 343 344 struct nf_conn *nf_ct_tmpl_alloc(struct net *net, 345 const struct nf_conntrack_zone *zone, 346 gfp_t flags); 347 void nf_ct_tmpl_free(struct nf_conn *tmpl); 348 349 u32 nf_ct_get_id(const struct nf_conn *ct); 350 u32 nf_conntrack_count(const struct net *net); 351 352 static inline void 353 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info) 354 { 355 skb_set_nfct(skb, (unsigned long)ct | info); 356 } 357 358 extern unsigned int nf_conntrack_net_id; 359 360 static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net) 361 { 362 return net_generic(net, nf_conntrack_net_id); 363 } 364 365 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count) 366 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count) 367 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v)) 368 369 #define MODULE_ALIAS_NFCT_HELPER(helper) \ 370 MODULE_ALIAS("nfct-helper-" helper) 371 372 #endif /* _NF_CONNTRACK_H */ 373