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/netfilter/nf_conntrack_common.h> 17 18 #include <linux/bitops.h> 19 #include <linux/compiler.h> 20 #include <linux/atomic.h> 21 22 #include <linux/netfilter/nf_conntrack_tcp.h> 23 #include <linux/netfilter/nf_conntrack_dccp.h> 24 #include <linux/netfilter/nf_conntrack_sctp.h> 25 #include <linux/netfilter/nf_conntrack_proto_gre.h> 26 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h> 27 28 #include <net/netfilter/nf_conntrack_tuple.h> 29 30 /* per conntrack: protocol private data */ 31 union nf_conntrack_proto { 32 /* insert conntrack proto private data here */ 33 struct nf_ct_dccp dccp; 34 struct ip_ct_sctp sctp; 35 struct ip_ct_tcp tcp; 36 struct nf_ct_gre gre; 37 unsigned int tmpl_padto; 38 }; 39 40 union nf_conntrack_expect_proto { 41 /* insert expect proto private data here */ 42 }; 43 44 #include <linux/types.h> 45 #include <linux/skbuff.h> 46 47 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> 48 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h> 49 50 struct nf_conn { 51 /* Usage count in here is 1 for hash table, 1 per skb, 52 * plus 1 for any connection(s) we are `master' for 53 * 54 * Hint, SKB address this struct and refcnt via skb->_nfct and 55 * helpers nf_conntrack_get() and nf_conntrack_put(). 56 * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt, 57 * beware nf_ct_get() is different and don't inc refcnt. 58 */ 59 struct nf_conntrack ct_general; 60 61 spinlock_t lock; 62 u16 cpu; 63 64 #ifdef CONFIG_NF_CONNTRACK_ZONES 65 struct nf_conntrack_zone zone; 66 #endif 67 /* XXX should I move this to the tail ? - Y.K */ 68 /* These are my tuples; original and reply */ 69 struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX]; 70 71 /* Have we seen traffic both ways yet? (bitset) */ 72 unsigned long status; 73 74 /* jiffies32 when this ct is considered dead */ 75 u32 timeout; 76 77 possible_net_t ct_net; 78 79 #if IS_ENABLED(CONFIG_NF_NAT) 80 struct hlist_node nat_bysource; 81 #endif 82 /* all members below initialized via memset */ 83 u8 __nfct_init_offset[0]; 84 85 /* If we were expected by an expectation, this will be it */ 86 struct nf_conn *master; 87 88 #if defined(CONFIG_NF_CONNTRACK_MARK) 89 u_int32_t mark; 90 #endif 91 92 #ifdef CONFIG_NF_CONNTRACK_SECMARK 93 u_int32_t secmark; 94 #endif 95 96 /* Extensions */ 97 struct nf_ct_ext *ext; 98 99 /* Storage reserved for other modules, must be the last member */ 100 union nf_conntrack_proto proto; 101 }; 102 103 static inline struct nf_conn * 104 nf_ct_tuplehash_to_ctrack(const struct nf_conntrack_tuple_hash *hash) 105 { 106 return container_of(hash, struct nf_conn, 107 tuplehash[hash->tuple.dst.dir]); 108 } 109 110 static inline u_int16_t nf_ct_l3num(const struct nf_conn *ct) 111 { 112 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num; 113 } 114 115 static inline u_int8_t nf_ct_protonum(const struct nf_conn *ct) 116 { 117 return ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum; 118 } 119 120 #define nf_ct_tuple(ct, dir) (&(ct)->tuplehash[dir].tuple) 121 122 /* get master conntrack via master expectation */ 123 #define master_ct(conntr) (conntr->master) 124 125 extern struct net init_net; 126 127 static inline struct net *nf_ct_net(const struct nf_conn *ct) 128 { 129 return read_pnet(&ct->ct_net); 130 } 131 132 /* Alter reply tuple (maybe alter helper). */ 133 void nf_conntrack_alter_reply(struct nf_conn *ct, 134 const struct nf_conntrack_tuple *newreply); 135 136 /* Is this tuple taken? (ignoring any belonging to the given 137 conntrack). */ 138 int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 139 const struct nf_conn *ignored_conntrack); 140 141 #define NFCT_INFOMASK 7UL 142 #define NFCT_PTRMASK ~(NFCT_INFOMASK) 143 144 /* Return conntrack_info and tuple hash for given skb. */ 145 static inline struct nf_conn * 146 nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo) 147 { 148 *ctinfo = skb->_nfct & NFCT_INFOMASK; 149 150 return (struct nf_conn *)(skb->_nfct & NFCT_PTRMASK); 151 } 152 153 /* decrement reference count on a conntrack */ 154 static inline void nf_ct_put(struct nf_conn *ct) 155 { 156 WARN_ON(!ct); 157 nf_conntrack_put(&ct->ct_general); 158 } 159 160 /* Protocol module loading */ 161 int nf_ct_l3proto_try_module_get(unsigned short l3proto); 162 void nf_ct_l3proto_module_put(unsigned short l3proto); 163 164 /* load module; enable/disable conntrack in this namespace */ 165 int nf_ct_netns_get(struct net *net, u8 nfproto); 166 void nf_ct_netns_put(struct net *net, u8 nfproto); 167 168 /* 169 * Allocate a hashtable of hlist_head (if nulls == 0), 170 * or hlist_nulls_head (if nulls == 1) 171 */ 172 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls); 173 174 void nf_ct_free_hashtable(void *hash, unsigned int size); 175 176 int nf_conntrack_hash_check_insert(struct nf_conn *ct); 177 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report); 178 179 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 180 u_int16_t l3num, struct net *net, 181 struct nf_conntrack_tuple *tuple); 182 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 183 const struct nf_conntrack_tuple *orig); 184 185 void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 186 const struct sk_buff *skb, 187 unsigned long extra_jiffies, int do_acct); 188 189 /* Refresh conntrack for this many jiffies and do accounting */ 190 static inline void nf_ct_refresh_acct(struct nf_conn *ct, 191 enum ip_conntrack_info ctinfo, 192 const struct sk_buff *skb, 193 unsigned long extra_jiffies) 194 { 195 __nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies, 1); 196 } 197 198 /* Refresh conntrack for this many jiffies */ 199 static inline void nf_ct_refresh(struct nf_conn *ct, 200 const struct sk_buff *skb, 201 unsigned long extra_jiffies) 202 { 203 __nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0); 204 } 205 206 /* kill conntrack and do accounting */ 207 bool nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 208 const struct sk_buff *skb); 209 210 /* kill conntrack without accounting */ 211 static inline bool nf_ct_kill(struct nf_conn *ct) 212 { 213 return nf_ct_delete(ct, 0, 0); 214 } 215 216 /* Set all unconfirmed conntrack as dying */ 217 void nf_ct_unconfirmed_destroy(struct net *); 218 219 /* Iterate over all conntracks: if iter returns true, it's deleted. */ 220 void nf_ct_iterate_cleanup_net(struct net *net, 221 int (*iter)(struct nf_conn *i, void *data), 222 void *data, u32 portid, int report); 223 224 /* also set unconfirmed conntracks as dying. Only use in module exit path. */ 225 void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), 226 void *data); 227 228 struct nf_conntrack_zone; 229 230 void nf_conntrack_free(struct nf_conn *ct); 231 struct nf_conn *nf_conntrack_alloc(struct net *net, 232 const struct nf_conntrack_zone *zone, 233 const struct nf_conntrack_tuple *orig, 234 const struct nf_conntrack_tuple *repl, 235 gfp_t gfp); 236 237 static inline int nf_ct_is_template(const struct nf_conn *ct) 238 { 239 return test_bit(IPS_TEMPLATE_BIT, &ct->status); 240 } 241 242 /* It's confirmed if it is, or has been in the hash table. */ 243 static inline int nf_ct_is_confirmed(const struct nf_conn *ct) 244 { 245 return test_bit(IPS_CONFIRMED_BIT, &ct->status); 246 } 247 248 static inline int nf_ct_is_dying(const struct nf_conn *ct) 249 { 250 return test_bit(IPS_DYING_BIT, &ct->status); 251 } 252 253 /* Packet is received from loopback */ 254 static inline bool nf_is_loopback_packet(const struct sk_buff *skb) 255 { 256 return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK; 257 } 258 259 #define nfct_time_stamp ((u32)(jiffies)) 260 261 /* jiffies until ct expires, 0 if already expired */ 262 static inline unsigned long nf_ct_expires(const struct nf_conn *ct) 263 { 264 s32 timeout = ct->timeout - nfct_time_stamp; 265 266 return timeout > 0 ? timeout : 0; 267 } 268 269 static inline bool nf_ct_is_expired(const struct nf_conn *ct) 270 { 271 return (__s32)(ct->timeout - nfct_time_stamp) <= 0; 272 } 273 274 /* use after obtaining a reference count */ 275 static inline bool nf_ct_should_gc(const struct nf_conn *ct) 276 { 277 return nf_ct_is_expired(ct) && nf_ct_is_confirmed(ct) && 278 !nf_ct_is_dying(ct); 279 } 280 281 struct kernel_param; 282 283 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp); 284 int nf_conntrack_hash_resize(unsigned int hashsize); 285 286 extern struct hlist_nulls_head *nf_conntrack_hash; 287 extern unsigned int nf_conntrack_htable_size; 288 extern seqcount_t nf_conntrack_generation; 289 extern unsigned int nf_conntrack_max; 290 291 /* must be called with rcu read lock held */ 292 static inline void 293 nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize) 294 { 295 struct hlist_nulls_head *hptr; 296 unsigned int sequence, hsz; 297 298 do { 299 sequence = read_seqcount_begin(&nf_conntrack_generation); 300 hsz = nf_conntrack_htable_size; 301 hptr = nf_conntrack_hash; 302 } while (read_seqcount_retry(&nf_conntrack_generation, sequence)); 303 304 *hash = hptr; 305 *hsize = hsz; 306 } 307 308 struct nf_conn *nf_ct_tmpl_alloc(struct net *net, 309 const struct nf_conntrack_zone *zone, 310 gfp_t flags); 311 void nf_ct_tmpl_free(struct nf_conn *tmpl); 312 313 static inline void 314 nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info) 315 { 316 skb->_nfct = (unsigned long)ct | info; 317 } 318 319 #define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count) 320 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count) 321 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v)) 322 323 #define MODULE_ALIAS_NFCT_HELPER(helper) \ 324 MODULE_ALIAS("nfct-helper-" helper) 325 326 #endif /* _NF_CONNTRACK_H */ 327