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 /* only used when new connection is allocated: */ 48 atomic_t count; 49 unsigned int expect_count; 50 u8 sysctl_auto_assign_helper; 51 bool auto_assign_helper_warned; 52 53 /* only used from work queues, configuration plane, and so on: */ 54 unsigned int users4; 55 unsigned int users6; 56 unsigned int users_bridge; 57 #ifdef CONFIG_SYSCTL 58 struct ctl_table_header *sysctl_header; 59 #endif 60 #ifdef CONFIG_NF_CONNTRACK_EVENTS 61 struct delayed_work ecache_dwork; 62 struct netns_ct *ct_net; 63 #endif 64 }; 65 66 #include <linux/types.h> 67 #include <linux/skbuff.h> 68 69 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> 70 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h> 71 72 struct nf_conn { 73 /* Usage count in here is 1 for hash table, 1 per skb, 74 * plus 1 for any connection(s) we are `master' for 75 * 76 * Hint, SKB address this struct and refcnt via skb->_nfct and 77 * helpers nf_conntrack_get() and nf_conntrack_put(). 78 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt, 79 * except that the latter uses internal indirection and does not 80 * result in a conntrack module dependency. 81 * beware nf_ct_get() is different and don't inc refcnt. 82 */ 83 struct nf_conntrack ct_general; 84 85 spinlock_t lock; 86 /* jiffies32 when this ct is considered dead */ 87 u32 timeout; 88 89 #ifdef CONFIG_NF_CONNTRACK_ZONES 90 struct nf_conntrack_zone zone; 91 #endif 92 /* XXX should I move this to the tail ? - Y.K */ 93 /* These are my tuples; original and reply */ 94 struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX]; 95 96 /* Have we seen traffic both ways yet? (bitset) */ 97 unsigned long status; 98 99 u16 cpu; 100 u16 local_origin:1; 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_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash) 129 { 130 return container_of(hash, struct nf_conn, 131 tuplehash[hash->tuple.dst.dir]); 132 } 133 134 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct) 135 { 136 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num; 137 } 138 139 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct) 140 { 141 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum; 142 } 143 144 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple) 145 146 /* get master conntrack via master expectation */ 147 #define master_ct(conntr) (conntr->master) 148 149 extern struct net init_net; 150 151 static inline struct net *nf_ct_net(const struct nf_conn *ct) 152 { 153 return read_pnet(&ct->ct_net); 154 } 155 156 /* Alter reply tuple (maybe alter helper). */ 157 void nf_conntrack_alter_reply(struct nf_conn *ct, 158 const struct nf_conntrack_tuple *newreply); 159 160 /* Is this tuple taken? (ignoring any belonging to the given 161 conntrack). */ 162 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 163 const struct nf_conn *ignored_conntrack); 164 165 /* Return conntrack_info and tuple hash for given skb. */ 166 static inline struct nf_conn * 167 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo) 168 { 169 unsigned long nfct = skb_get_nfct(skb); 170 171 *ctinfo = nfct & NFCT_INFOMASK; 172 return (struct nf_conn *)(nfct & NFCT_PTRMASK); 173 } 174 175 void nf_ct_destroy(struct nf_conntrack *nfct); 176 177 /* decrement reference count on a conntrack */ 178 static inline void nf_ct_put(struct nf_conn *ct) 179 { 180 if (ct && refcount_dec_and_test(&ct->ct_general.use)) 181 nf_ct_destroy(&ct->ct_general); 182 } 183 184 /* Protocol module loading */ 185 int nf_ct_l3proto_try_module_get(unsigned short l3proto); 186 void nf_ct_l3proto_module_put(unsigned short l3proto); 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 const struct sk_buff *skb, 207 u32 extra_jiffies, bool do_acct); 208 209 /* Refresh conntrack for this many jiffies and do accounting */ 210 static inline void nf_ct_refresh_acct(struct nf_conn *ct, 211 enum ip_conntrack_info ctinfo, 212 const struct sk_buff *skb, 213 u32 extra_jiffies) 214 { 215 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true); 216 } 217 218 /* Refresh conntrack for this many jiffies */ 219 static inline void nf_ct_refresh(struct nf_conn *ct, 220 const struct sk_buff *skb, 221 u32 extra_jiffies) 222 { 223 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false); 224 } 225 226 /* kill conntrack and do accounting */ 227 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 228 const struct sk_buff *skb); 229 230 /* kill conntrack without accounting */ 231 static inline bool nf_ct_kill(struct nf_conn *ct) 232 { 233 return nf_ct_delete(ct, 0, 0); 234 } 235 236 /* Set all unconfirmed conntrack as dying */ 237 void nf_ct_unconfirmed_destroy(struct net *); 238 239 /* Iterate over all conntracks: if iter returns true, it's deleted. */ 240 void nf_ct_iterate_cleanup_net(struct net *net, 241 int (*iter)(struct nf_conn *i, void *data), 242 void *data, u32 portid, int report); 243 244 /* also set unconfirmed conntracks as dying. Only use in module exit path. */ 245 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), 246 void *data); 247 248 struct nf_conntrack_zone; 249 250 void nf_conntrack_free(struct nf_conn *ct); 251 struct nf_conn *nf_conntrack_alloc(struct net *net, 252 const struct nf_conntrack_zone *zone, 253 const struct nf_conntrack_tuple *orig, 254 const struct nf_conntrack_tuple *repl, 255 gfp_t gfp); 256 257 static inline int nf_ct_is_template(const struct nf_conn *ct) 258 { 259 return test_bit(IPS_TEMPLATE_BIT, &ct->status); 260 } 261 262 /* It's confirmed if it is, or has been in the hash table. */ 263 static inline int nf_ct_is_confirmed(const struct nf_conn *ct) 264 { 265 return test_bit(IPS_CONFIRMED_BIT, &ct->status); 266 } 267 268 static inline int nf_ct_is_dying(const struct nf_conn *ct) 269 { 270 return test_bit(IPS_DYING_BIT, &ct->status); 271 } 272 273 /* Packet is received from loopback */ 274 static inline bool nf_is_loopback_packet(const struct sk_buff *skb) 275 { 276 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK; 277 } 278 279 #define nfct_time_stamp ((u32)(jiffies)) 280 281 /* jiffies until ct expires, 0 if already expired */ 282 static inline unsigned long nf_ct_expires(const struct nf_conn *ct) 283 { 284 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp; 285 286 return max(timeout, 0); 287 } 288 289 static inline bool nf_ct_is_expired(const struct nf_conn *ct) 290 { 291 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0; 292 } 293 294 /* use after obtaining a reference count */ 295 static inline bool nf_ct_should_gc(const struct nf_conn *ct) 296 { 297 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) && 298 !nf_ct_is_dying(ct); 299 } 300 301 #define NF_CT_DAY (86400 * HZ) 302 303 /* Set an arbitrary timeout large enough not to ever expire, this save 304 * us a check for the IPS_OFFLOAD_BIT from the packet path via 305 * nf_ct_is_expired(). 306 */ 307 static inline void nf_ct_offload_timeout(struct nf_conn *ct) 308 { 309 if (nf_ct_expires(ct) < NF_CT_DAY / 2) 310 WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY); 311 } 312 313 struct kernel_param; 314 315 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp); 316 int nf_conntrack_hash_resize(unsigned int hashsize); 317 318 extern struct hlist_nulls_head *nf_conntrack_hash; 319 extern unsigned int nf_conntrack_htable_size; 320 extern seqcount_spinlock_t nf_conntrack_generation; 321 extern unsigned int nf_conntrack_max; 322 323 /* must be called with rcu read lock held */ 324 static inline void 325 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize) 326 { 327 struct hlist_nulls_head *hptr; 328 unsigned int sequence, hsz; 329 330 do { 331 sequence = read_seqcount_begin(&nf_conntrack_generation); 332 hsz = nf_conntrack_htable_size; 333 hptr = nf_conntrack_hash; 334 } while (read_seqcount_retry(&nf_conntrack_generation, sequence)); 335 336 *hash = hptr; 337 *hsize = hsz; 338 } 339 340 struct nf_conn *nf_ct_tmpl_alloc(struct net *net, 341 const struct nf_conntrack_zone *zone, 342 gfp_t flags); 343 void nf_ct_tmpl_free(struct nf_conn *tmpl); 344 345 u32 nf_ct_get_id(const struct nf_conn *ct); 346 u32 nf_conntrack_count(const struct net *net); 347 348 static inline void 349 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info) 350 { 351 skb_set_nfct(skb, (unsigned long)ct | info); 352 } 353 354 extern unsigned int nf_conntrack_net_id; 355 356 static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net) 357 { 358 return net_generic(net, nf_conntrack_net_id); 359 } 360 361 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count) 362 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count) 363 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v)) 364 365 #define MODULE_ALIAS_NFCT_HELPER(helper) \ 366 MODULE_ALIAS("nfct-helper-" helper) 367 368 #endif /* _NF_CONNTRACK_H */ 369