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