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 #define NF_CT_DAY (86400 * HZ) 283 284 /* Set an arbitrary timeout large enough not to ever expire, this save 285 * us a check for the IPS_OFFLOAD_BIT from the packet path via 286 * nf_ct_is_expired(). 287 */ 288 static inline void nf_ct_offload_timeout(struct nf_conn *ct) 289 { 290 if (nf_ct_expires(ct) < NF_CT_DAY / 2) 291 ct->timeout = nfct_time_stamp + NF_CT_DAY; 292 } 293 294 struct kernel_param; 295 296 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp); 297 int nf_conntrack_hash_resize(unsigned int hashsize); 298 299 extern struct hlist_nulls_head *nf_conntrack_hash; 300 extern unsigned int nf_conntrack_htable_size; 301 extern seqcount_spinlock_t nf_conntrack_generation; 302 extern unsigned int nf_conntrack_max; 303 304 /* must be called with rcu read lock held */ 305 static inline void 306 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize) 307 { 308 struct hlist_nulls_head *hptr; 309 unsigned int sequence, hsz; 310 311 do { 312 sequence = read_seqcount_begin(&nf_conntrack_generation); 313 hsz = nf_conntrack_htable_size; 314 hptr = nf_conntrack_hash; 315 } while (read_seqcount_retry(&nf_conntrack_generation, sequence)); 316 317 *hash = hptr; 318 *hsize = hsz; 319 } 320 321 struct nf_conn *nf_ct_tmpl_alloc(struct net *net, 322 const struct nf_conntrack_zone *zone, 323 gfp_t flags); 324 void nf_ct_tmpl_free(struct nf_conn *tmpl); 325 326 u32 nf_ct_get_id(const struct nf_conn *ct); 327 328 static inline void 329 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info) 330 { 331 skb_set_nfct(skb, (unsigned long)ct | info); 332 } 333 334 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count) 335 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count) 336 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v)) 337 338 #define MODULE_ALIAS_NFCT_HELPER(helper) \ 339 MODULE_ALIAS("nfct-helper-" helper) 340 341 #endif /* _NF_CONNTRACK_H */ 342