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 * beware nf_ct_get() is different and don't inc refcnt. 80 */ 81 struct nf_conntrack ct_general; 82 83 spinlock_t lock; 84 /* jiffies32 when this ct is considered dead */ 85 u32 timeout; 86 87 #ifdef CONFIG_NF_CONNTRACK_ZONES 88 struct nf_conntrack_zone zone; 89 #endif 90 /* XXX should I move this to the tail ? - Y.K */ 91 /* These are my tuples; original and reply */ 92 struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX]; 93 94 /* Have we seen traffic both ways yet? (bitset) */ 95 unsigned long status; 96 97 u16 cpu; 98 possible_net_t ct_net; 99 100 #if IS_ENABLED(CONFIG_NF_NAT) 101 struct hlist_node nat_bysource; 102 #endif 103 /* all members below initialized via memset */ 104 struct { } __nfct_init_offset; 105 106 /* If we were expected by an expectation, this will be it */ 107 struct nf_conn *master; 108 109 #if defined(CONFIG_NF_CONNTRACK_MARK) 110 u_int32_t mark; 111 #endif 112 113 #ifdef CONFIG_NF_CONNTRACK_SECMARK 114 u_int32_t secmark; 115 #endif 116 117 /* Extensions */ 118 struct nf_ct_ext *ext; 119 120 /* Storage reserved for other modules, must be the last member */ 121 union nf_conntrack_proto proto; 122 }; 123 124 static inline struct nf_conn * nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash * hash)125 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash) 126 { 127 return container_of(hash, struct nf_conn, 128 tuplehash[hash->tuple.dst.dir]); 129 } 130 nf_ct_l3num(const struct nf_conn * ct)131 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct) 132 { 133 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num; 134 } 135 nf_ct_protonum(const struct nf_conn * ct)136 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct) 137 { 138 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum; 139 } 140 141 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple) 142 143 /* get master conntrack via master expectation */ 144 #define master_ct(conntr) (conntr->master) 145 146 extern struct net init_net; 147 nf_ct_net(const struct nf_conn * ct)148 static inline struct net *nf_ct_net(const struct nf_conn *ct) 149 { 150 return read_pnet(&ct->ct_net); 151 } 152 153 /* Alter reply tuple (maybe alter helper). */ 154 void nf_conntrack_alter_reply(struct nf_conn *ct, 155 const struct nf_conntrack_tuple *newreply); 156 157 /* Is this tuple taken? (ignoring any belonging to the given 158 conntrack). */ 159 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 160 const struct nf_conn *ignored_conntrack); 161 162 /* Return conntrack_info and tuple hash for given skb. */ 163 static inline struct nf_conn * nf_ct_get(const struct sk_buff * skb,enum ip_conntrack_info * ctinfo)164 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo) 165 { 166 unsigned long nfct = skb_get_nfct(skb); 167 168 *ctinfo = nfct & NFCT_INFOMASK; 169 return (struct nf_conn *)(nfct & NFCT_PTRMASK); 170 } 171 172 /* decrement reference count on a conntrack */ nf_ct_put(struct nf_conn * ct)173 static inline void nf_ct_put(struct nf_conn *ct) 174 { 175 WARN_ON(!ct); 176 nf_conntrack_put(&ct->ct_general); 177 } 178 179 /* Protocol module loading */ 180 int nf_ct_l3proto_try_module_get(unsigned short l3proto); 181 void nf_ct_l3proto_module_put(unsigned short l3proto); 182 183 /* load module; enable/disable conntrack in this namespace */ 184 int nf_ct_netns_get(struct net *net, u8 nfproto); 185 void nf_ct_netns_put(struct net *net, u8 nfproto); 186 187 /* 188 * Allocate a hashtable of hlist_head (if nulls == 0), 189 * or hlist_nulls_head (if nulls == 1) 190 */ 191 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls); 192 193 int nf_conntrack_hash_check_insert(struct nf_conn *ct); 194 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report); 195 196 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 197 u_int16_t l3num, struct net *net, 198 struct nf_conntrack_tuple *tuple); 199 200 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 201 const struct sk_buff *skb, 202 u32 extra_jiffies, bool do_acct); 203 204 /* Refresh conntrack for this many jiffies and do accounting */ nf_ct_refresh_acct(struct nf_conn * ct,enum ip_conntrack_info ctinfo,const struct sk_buff * skb,u32 extra_jiffies)205 static inline void nf_ct_refresh_acct(struct nf_conn *ct, 206 enum ip_conntrack_info ctinfo, 207 const struct sk_buff *skb, 208 u32 extra_jiffies) 209 { 210 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, true); 211 } 212 213 /* Refresh conntrack for this many jiffies */ nf_ct_refresh(struct nf_conn * ct,const struct sk_buff * skb,u32 extra_jiffies)214 static inline void nf_ct_refresh(struct nf_conn *ct, 215 const struct sk_buff *skb, 216 u32 extra_jiffies) 217 { 218 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, false); 219 } 220 221 /* kill conntrack and do accounting */ 222 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 223 const struct sk_buff *skb); 224 225 /* kill conntrack without accounting */ nf_ct_kill(struct nf_conn * ct)226 static inline bool nf_ct_kill(struct nf_conn *ct) 227 { 228 return nf_ct_delete(ct, 0, 0); 229 } 230 231 /* Set all unconfirmed conntrack as dying */ 232 void nf_ct_unconfirmed_destroy(struct net *); 233 234 /* Iterate over all conntracks: if iter returns true, it's deleted. */ 235 void nf_ct_iterate_cleanup_net(struct net *net, 236 int (*iter)(struct nf_conn *i, void *data), 237 void *data, u32 portid, int report); 238 239 /* also set unconfirmed conntracks as dying. Only use in module exit path. */ 240 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), 241 void *data); 242 243 struct nf_conntrack_zone; 244 245 void nf_conntrack_free(struct nf_conn *ct); 246 struct nf_conn *nf_conntrack_alloc(struct net *net, 247 const struct nf_conntrack_zone *zone, 248 const struct nf_conntrack_tuple *orig, 249 const struct nf_conntrack_tuple *repl, 250 gfp_t gfp); 251 nf_ct_is_template(const struct nf_conn * ct)252 static inline int nf_ct_is_template(const struct nf_conn *ct) 253 { 254 return test_bit(IPS_TEMPLATE_BIT, &ct->status); 255 } 256 257 /* It's confirmed if it is, or has been in the hash table. */ nf_ct_is_confirmed(const struct nf_conn * ct)258 static inline int nf_ct_is_confirmed(const struct nf_conn *ct) 259 { 260 return test_bit(IPS_CONFIRMED_BIT, &ct->status); 261 } 262 nf_ct_is_dying(const struct nf_conn * ct)263 static inline int nf_ct_is_dying(const struct nf_conn *ct) 264 { 265 return test_bit(IPS_DYING_BIT, &ct->status); 266 } 267 268 /* Packet is received from loopback */ nf_is_loopback_packet(const struct sk_buff * skb)269 static inline bool nf_is_loopback_packet(const struct sk_buff *skb) 270 { 271 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK; 272 } 273 274 #define nfct_time_stamp ((u32)(jiffies)) 275 276 /* jiffies until ct expires, 0 if already expired */ nf_ct_expires(const struct nf_conn * ct)277 static inline unsigned long nf_ct_expires(const struct nf_conn *ct) 278 { 279 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp; 280 281 return timeout > 0 ? timeout : 0; 282 } 283 nf_ct_is_expired(const struct nf_conn * ct)284 static inline bool nf_ct_is_expired(const struct nf_conn *ct) 285 { 286 return (__s32)(READ_ONCE(ct->timeout) - nfct_time_stamp) <= 0; 287 } 288 289 /* use after obtaining a reference count */ nf_ct_should_gc(const struct nf_conn * ct)290 static inline bool nf_ct_should_gc(const struct nf_conn *ct) 291 { 292 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) && 293 !nf_ct_is_dying(ct); 294 } 295 296 #define NF_CT_DAY (86400 * HZ) 297 298 /* Set an arbitrary timeout large enough not to ever expire, this save 299 * us a check for the IPS_OFFLOAD_BIT from the packet path via 300 * nf_ct_is_expired(). 301 */ nf_ct_offload_timeout(struct nf_conn * ct)302 static inline void nf_ct_offload_timeout(struct nf_conn *ct) 303 { 304 if (nf_ct_expires(ct) < NF_CT_DAY / 2) 305 WRITE_ONCE(ct->timeout, nfct_time_stamp + NF_CT_DAY); 306 } 307 308 struct kernel_param; 309 310 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp); 311 int nf_conntrack_hash_resize(unsigned int hashsize); 312 313 extern struct hlist_nulls_head *nf_conntrack_hash; 314 extern unsigned int nf_conntrack_htable_size; 315 extern seqcount_spinlock_t nf_conntrack_generation; 316 extern unsigned int nf_conntrack_max; 317 318 /* must be called with rcu read lock held */ 319 static inline void nf_conntrack_get_ht(struct hlist_nulls_head ** hash,unsigned int * hsize)320 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize) 321 { 322 struct hlist_nulls_head *hptr; 323 unsigned int sequence, hsz; 324 325 do { 326 sequence = read_seqcount_begin(&nf_conntrack_generation); 327 hsz = nf_conntrack_htable_size; 328 hptr = nf_conntrack_hash; 329 } while (read_seqcount_retry(&nf_conntrack_generation, sequence)); 330 331 *hash = hptr; 332 *hsize = hsz; 333 } 334 335 struct nf_conn *nf_ct_tmpl_alloc(struct net *net, 336 const struct nf_conntrack_zone *zone, 337 gfp_t flags); 338 void nf_ct_tmpl_free(struct nf_conn *tmpl); 339 340 u32 nf_ct_get_id(const struct nf_conn *ct); 341 u32 nf_conntrack_count(const struct net *net); 342 343 static inline void nf_ct_set(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info info)344 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info) 345 { 346 skb_set_nfct(skb, (unsigned long)ct | info); 347 } 348 349 extern unsigned int nf_conntrack_net_id; 350 nf_ct_pernet(const struct net * net)351 static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net) 352 { 353 return net_generic(net, nf_conntrack_net_id); 354 } 355 356 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count) 357 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count) 358 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v)) 359 360 #define MODULE_ALIAS_NFCT_HELPER(helper) \ 361 MODULE_ALIAS("nfct-helper-" helper) 362 363 #endif /* _NF_CONNTRACK_H */ 364