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); 113 114 /* Functions to register get/setsockopt ranges (non-inclusive). You 115 need to check permissions yourself! */ 116 int nf_register_sockopt(struct nf_sockopt_ops *reg); 117 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 118 119 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 120 121 /* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will 122 * disappear once iptables is replaced with pkttables. Please DO NOT use them 123 * for any new code! */ 124 #define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */ 125 #define NF_LOG_TCPOPT 0x02 /* Log TCP options */ 126 #define NF_LOG_IPOPT 0x04 /* Log IP options */ 127 #define NF_LOG_UID 0x08 /* Log UID owning local socket */ 128 #define NF_LOG_MASK 0x0f 129 130 #define NF_LOG_TYPE_LOG 0x01 131 #define NF_LOG_TYPE_ULOG 0x02 132 133 struct nf_loginfo { 134 u_int8_t type; 135 union { 136 struct { 137 u_int32_t copy_len; 138 u_int16_t group; 139 u_int16_t qthreshold; 140 } ulog; 141 struct { 142 u_int8_t level; 143 u_int8_t logflags; 144 } log; 145 } u; 146 }; 147 148 typedef void nf_logfn(unsigned int pf, 149 unsigned int hooknum, 150 const struct sk_buff *skb, 151 const struct net_device *in, 152 const struct net_device *out, 153 const struct nf_loginfo *li, 154 const char *prefix); 155 156 struct nf_logger { 157 struct module *me; 158 nf_logfn *logfn; 159 char *name; 160 }; 161 162 /* Function to register/unregister log function. */ 163 int nf_log_register(int pf, struct nf_logger *logger); 164 int nf_log_unregister_pf(int pf); 165 void nf_log_unregister_logger(struct nf_logger *logger); 166 167 /* Calls the registered backend logging function */ 168 void nf_log_packet(int pf, 169 unsigned int hooknum, 170 const struct sk_buff *skb, 171 const struct net_device *in, 172 const struct net_device *out, 173 struct nf_loginfo *li, 174 const char *fmt, ...); 175 176 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb, 177 struct net_device *indev, struct net_device *outdev, 178 int (*okfn)(struct sk_buff *), int thresh); 179 180 /** 181 * nf_hook_thresh - call a netfilter hook 182 * 183 * Returns 1 if the hook has allowed the packet to pass. The function 184 * okfn must be invoked by the caller in this case. Any other return 185 * value indicates the packet has been consumed by the hook. 186 */ 187 static inline int nf_hook_thresh(int pf, unsigned int hook, 188 struct sk_buff **pskb, 189 struct net_device *indev, 190 struct net_device *outdev, 191 int (*okfn)(struct sk_buff *), int thresh, 192 int cond) 193 { 194 if (!cond) 195 return 1; 196 #ifndef CONFIG_NETFILTER_DEBUG 197 if (list_empty(&nf_hooks[pf][hook])) 198 return 1; 199 #endif 200 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh); 201 } 202 203 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 204 struct net_device *indev, struct net_device *outdev, 205 int (*okfn)(struct sk_buff *)) 206 { 207 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1); 208 } 209 210 /* Activate hook; either okfn or kfree_skb called, unless a hook 211 returns NF_STOLEN (in which case, it's up to the hook to deal with 212 the consequences). 213 214 Returns -ERRNO if packet dropped. Zero means queued, stolen or 215 accepted. 216 */ 217 218 /* RR: 219 > I don't want nf_hook to return anything because people might forget 220 > about async and trust the return value to mean "packet was ok". 221 222 AK: 223 Just document it clearly, then you can expect some sense from kernel 224 coders :) 225 */ 226 227 /* This is gross, but inline doesn't cut it for avoiding the function 228 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 229 230 /* HX: It's slightly less gross now. */ 231 232 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 233 ({int __ret; \ 234 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\ 235 __ret = (okfn)(skb); \ 236 __ret;}) 237 238 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 239 ({int __ret; \ 240 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 241 __ret = (okfn)(skb); \ 242 __ret;}) 243 244 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 245 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 246 247 /* Call setsockopt() */ 248 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 249 int len); 250 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 251 int *len); 252 253 int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 254 char __user *opt, int len); 255 int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 256 char __user *opt, int *len); 257 258 /* Packet queuing */ 259 struct nf_queue_handler { 260 int (*outfn)(struct sk_buff *skb, struct nf_info *info, 261 unsigned int queuenum, void *data); 262 void *data; 263 char *name; 264 }; 265 extern int nf_register_queue_handler(int pf, 266 struct nf_queue_handler *qh); 267 extern int nf_unregister_queue_handler(int pf); 268 extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh); 269 extern void nf_reinject(struct sk_buff *skb, 270 struct nf_info *info, 271 unsigned int verdict); 272 273 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 274 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 275 276 /* FIXME: Before cache is ever used, this must be implemented for real. */ 277 extern void nf_invalidate_cache(int pf); 278 279 /* Call this before modifying an existing packet: ensures it is 280 modifiable and linear to the point you care about (writable_len). 281 Returns true or false. */ 282 extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len); 283 284 struct nf_queue_rerouter { 285 void (*save)(const struct sk_buff *skb, struct nf_info *info); 286 int (*reroute)(struct sk_buff **skb, const struct nf_info *info); 287 int rer_size; 288 }; 289 290 #define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info)) 291 292 extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer); 293 extern int nf_unregister_queue_rerouter(int pf); 294 295 #include <net/flow.h> 296 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 297 298 static inline void 299 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 300 { 301 #ifdef CONFIG_IP_NF_NAT_NEEDED 302 void (*decodefn)(struct sk_buff *, struct flowi *); 303 304 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 305 decodefn(skb, fl); 306 #endif 307 } 308 309 #ifdef CONFIG_PROC_FS 310 #include <linux/proc_fs.h> 311 extern struct proc_dir_entry *proc_net_netfilter; 312 #endif 313 314 #else /* !CONFIG_NETFILTER */ 315 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 316 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 317 static inline int nf_hook_thresh(int pf, unsigned int hook, 318 struct sk_buff **pskb, 319 struct net_device *indev, 320 struct net_device *outdev, 321 int (*okfn)(struct sk_buff *), int thresh, 322 int cond) 323 { 324 return okfn(*pskb); 325 } 326 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 327 struct net_device *indev, struct net_device *outdev, 328 int (*okfn)(struct sk_buff *)) 329 { 330 return 1; 331 } 332 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 333 struct flowi; 334 static inline void 335 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 336 #endif /*CONFIG_NETFILTER*/ 337 338 #endif /*__KERNEL__*/ 339 #endif /*__LINUX_NETFILTER_H*/ 340