1 #ifndef __LINUX_NETFILTER_H 2 #define __LINUX_NETFILTER_H 3 4 #ifdef __KERNEL__ 5 #include <linux/init.h> 6 #include <linux/types.h> 7 #include <linux/skbuff.h> 8 #include <linux/net.h> 9 #include <linux/if.h> 10 #include <linux/wait.h> 11 #include <linux/list.h> 12 #endif 13 #include <linux/compiler.h> 14 15 /* Responses from hook functions. */ 16 #define NF_DROP 0 17 #define NF_ACCEPT 1 18 #define NF_STOLEN 2 19 #define NF_QUEUE 3 20 #define NF_REPEAT 4 21 #define NF_STOP 5 22 #define NF_MAX_VERDICT NF_STOP 23 24 /* we overload the higher bits for encoding auxiliary data such as the queue 25 * number. Not nice, but better than additional function arguments. */ 26 #define NF_VERDICT_MASK 0x0000ffff 27 #define NF_VERDICT_BITS 16 28 29 #define NF_VERDICT_QMASK 0xffff0000 30 #define NF_VERDICT_QBITS 16 31 32 #define NF_QUEUE_NR(x) (((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK) | NF_QUEUE) 33 34 /* only for userspace compatibility */ 35 #ifndef __KERNEL__ 36 /* Generic cache responses from hook functions. 37 <= 0x2000 is used for protocol-flags. */ 38 #define NFC_UNKNOWN 0x4000 39 #define NFC_ALTERED 0x8000 40 #endif 41 42 #ifdef __KERNEL__ 43 #include <linux/config.h> 44 #ifdef CONFIG_NETFILTER 45 46 extern void netfilter_init(void); 47 48 /* Largest hook number + 1 */ 49 #define NF_MAX_HOOKS 8 50 51 struct sk_buff; 52 struct net_device; 53 54 typedef unsigned int nf_hookfn(unsigned int hooknum, 55 struct sk_buff **skb, 56 const struct net_device *in, 57 const struct net_device *out, 58 int (*okfn)(struct sk_buff *)); 59 60 struct nf_hook_ops 61 { 62 struct list_head list; 63 64 /* User fills in from here down. */ 65 nf_hookfn *hook; 66 struct module *owner; 67 int pf; 68 int hooknum; 69 /* Hooks are ordered in ascending priority. */ 70 int priority; 71 }; 72 73 struct nf_sockopt_ops 74 { 75 struct list_head list; 76 77 int pf; 78 79 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 80 int set_optmin; 81 int set_optmax; 82 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 83 int (*compat_set)(struct sock *sk, int optval, 84 void __user *user, unsigned int len); 85 86 int get_optmin; 87 int get_optmax; 88 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 89 int (*compat_get)(struct sock *sk, int optval, 90 void __user *user, int *len); 91 92 /* Number of users inside set() or get(). */ 93 unsigned int use; 94 struct task_struct *cleanup_task; 95 }; 96 97 /* Each queued (to userspace) skbuff has one of these. */ 98 struct nf_info 99 { 100 /* The ops struct which sent us to userspace. */ 101 struct nf_hook_ops *elem; 102 103 /* If we're sent to userspace, this keeps housekeeping info */ 104 int pf; 105 unsigned int hook; 106 struct net_device *indev, *outdev; 107 int (*okfn)(struct sk_buff *); 108 }; 109 110 /* Function to register/unregister hook points. */ 111 int nf_register_hook(struct nf_hook_ops *reg); 112 void nf_unregister_hook(struct nf_hook_ops *reg); 113 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 114 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 115 116 /* Functions to register get/setsockopt ranges (non-inclusive). You 117 need to check permissions yourself! */ 118 int nf_register_sockopt(struct nf_sockopt_ops *reg); 119 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 120 121 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 122 123 /* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will 124 * disappear once iptables is replaced with pkttables. Please DO NOT use them 125 * for any new code! */ 126 #define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */ 127 #define NF_LOG_TCPOPT 0x02 /* Log TCP options */ 128 #define NF_LOG_IPOPT 0x04 /* Log IP options */ 129 #define NF_LOG_UID 0x08 /* Log UID owning local socket */ 130 #define NF_LOG_MASK 0x0f 131 132 #define NF_LOG_TYPE_LOG 0x01 133 #define NF_LOG_TYPE_ULOG 0x02 134 135 struct nf_loginfo { 136 u_int8_t type; 137 union { 138 struct { 139 u_int32_t copy_len; 140 u_int16_t group; 141 u_int16_t qthreshold; 142 } ulog; 143 struct { 144 u_int8_t level; 145 u_int8_t logflags; 146 } log; 147 } u; 148 }; 149 150 typedef void nf_logfn(unsigned int pf, 151 unsigned int hooknum, 152 const struct sk_buff *skb, 153 const struct net_device *in, 154 const struct net_device *out, 155 const struct nf_loginfo *li, 156 const char *prefix); 157 158 struct nf_logger { 159 struct module *me; 160 nf_logfn *logfn; 161 char *name; 162 }; 163 164 /* Function to register/unregister log function. */ 165 int nf_log_register(int pf, struct nf_logger *logger); 166 int nf_log_unregister_pf(int pf); 167 void nf_log_unregister_logger(struct nf_logger *logger); 168 169 /* Calls the registered backend logging function */ 170 void nf_log_packet(int pf, 171 unsigned int hooknum, 172 const struct sk_buff *skb, 173 const struct net_device *in, 174 const struct net_device *out, 175 struct nf_loginfo *li, 176 const char *fmt, ...); 177 178 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb, 179 struct net_device *indev, struct net_device *outdev, 180 int (*okfn)(struct sk_buff *), int thresh); 181 182 /** 183 * nf_hook_thresh - call a netfilter hook 184 * 185 * Returns 1 if the hook has allowed the packet to pass. The function 186 * okfn must be invoked by the caller in this case. Any other return 187 * value indicates the packet has been consumed by the hook. 188 */ 189 static inline int nf_hook_thresh(int pf, unsigned int hook, 190 struct sk_buff **pskb, 191 struct net_device *indev, 192 struct net_device *outdev, 193 int (*okfn)(struct sk_buff *), int thresh, 194 int cond) 195 { 196 if (!cond) 197 return 1; 198 #ifndef CONFIG_NETFILTER_DEBUG 199 if (list_empty(&nf_hooks[pf][hook])) 200 return 1; 201 #endif 202 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh); 203 } 204 205 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 206 struct net_device *indev, struct net_device *outdev, 207 int (*okfn)(struct sk_buff *)) 208 { 209 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1); 210 } 211 212 /* Activate hook; either okfn or kfree_skb called, unless a hook 213 returns NF_STOLEN (in which case, it's up to the hook to deal with 214 the consequences). 215 216 Returns -ERRNO if packet dropped. Zero means queued, stolen or 217 accepted. 218 */ 219 220 /* RR: 221 > I don't want nf_hook to return anything because people might forget 222 > about async and trust the return value to mean "packet was ok". 223 224 AK: 225 Just document it clearly, then you can expect some sense from kernel 226 coders :) 227 */ 228 229 /* This is gross, but inline doesn't cut it for avoiding the function 230 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 231 232 /* HX: It's slightly less gross now. */ 233 234 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 235 ({int __ret; \ 236 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\ 237 __ret = (okfn)(skb); \ 238 __ret;}) 239 240 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 241 ({int __ret; \ 242 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 243 __ret = (okfn)(skb); \ 244 __ret;}) 245 246 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 247 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 248 249 /* Call setsockopt() */ 250 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 251 int len); 252 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 253 int *len); 254 255 int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 256 char __user *opt, int len); 257 int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 258 char __user *opt, int *len); 259 260 /* Packet queuing */ 261 struct nf_queue_handler { 262 int (*outfn)(struct sk_buff *skb, struct nf_info *info, 263 unsigned int queuenum, void *data); 264 void *data; 265 char *name; 266 }; 267 extern int nf_register_queue_handler(int pf, 268 struct nf_queue_handler *qh); 269 extern int nf_unregister_queue_handler(int pf); 270 extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh); 271 extern void nf_reinject(struct sk_buff *skb, 272 struct nf_info *info, 273 unsigned int verdict); 274 275 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 276 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 277 278 /* FIXME: Before cache is ever used, this must be implemented for real. */ 279 extern void nf_invalidate_cache(int pf); 280 281 /* Call this before modifying an existing packet: ensures it is 282 modifiable and linear to the point you care about (writable_len). 283 Returns true or false. */ 284 extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len); 285 286 struct nf_afinfo { 287 unsigned short family; 288 unsigned int (*checksum)(struct sk_buff *skb, unsigned int hook, 289 unsigned int dataoff, u_int8_t protocol); 290 void (*saveroute)(const struct sk_buff *skb, 291 struct nf_info *info); 292 int (*reroute)(struct sk_buff **skb, 293 const struct nf_info *info); 294 int route_key_size; 295 }; 296 297 extern struct nf_afinfo *nf_afinfo[]; 298 static inline struct nf_afinfo *nf_get_afinfo(unsigned short family) 299 { 300 return rcu_dereference(nf_afinfo[family]); 301 } 302 303 static inline unsigned int 304 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 305 u_int8_t protocol, unsigned short family) 306 { 307 struct nf_afinfo *afinfo; 308 unsigned int csum = 0; 309 310 rcu_read_lock(); 311 afinfo = nf_get_afinfo(family); 312 if (afinfo) 313 csum = afinfo->checksum(skb, hook, dataoff, protocol); 314 rcu_read_unlock(); 315 return csum; 316 } 317 318 extern int nf_register_afinfo(struct nf_afinfo *afinfo); 319 extern void nf_unregister_afinfo(struct nf_afinfo *afinfo); 320 321 #define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info)) 322 323 #include <net/flow.h> 324 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 325 326 static inline void 327 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 328 { 329 #ifdef CONFIG_IP_NF_NAT_NEEDED 330 void (*decodefn)(struct sk_buff *, struct flowi *); 331 332 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 333 decodefn(skb, fl); 334 #endif 335 } 336 337 #ifdef CONFIG_PROC_FS 338 #include <linux/proc_fs.h> 339 extern struct proc_dir_entry *proc_net_netfilter; 340 #endif 341 342 #else /* !CONFIG_NETFILTER */ 343 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 344 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 345 static inline int nf_hook_thresh(int pf, unsigned int hook, 346 struct sk_buff **pskb, 347 struct net_device *indev, 348 struct net_device *outdev, 349 int (*okfn)(struct sk_buff *), int thresh, 350 int cond) 351 { 352 return okfn(*pskb); 353 } 354 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 355 struct net_device *indev, struct net_device *outdev, 356 int (*okfn)(struct sk_buff *)) 357 { 358 return 1; 359 } 360 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 361 struct flowi; 362 static inline void 363 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 364 #endif /*CONFIG_NETFILTER*/ 365 366 #endif /*__KERNEL__*/ 367 #endif /*__LINUX_NETFILTER_H*/ 368