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 84 int get_optmin; 85 int get_optmax; 86 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 87 88 /* Number of users inside set() or get(). */ 89 unsigned int use; 90 struct task_struct *cleanup_task; 91 }; 92 93 /* Each queued (to userspace) skbuff has one of these. */ 94 struct nf_info 95 { 96 /* The ops struct which sent us to userspace. */ 97 struct nf_hook_ops *elem; 98 99 /* If we're sent to userspace, this keeps housekeeping info */ 100 int pf; 101 unsigned int hook; 102 struct net_device *indev, *outdev; 103 int (*okfn)(struct sk_buff *); 104 }; 105 106 /* Function to register/unregister hook points. */ 107 int nf_register_hook(struct nf_hook_ops *reg); 108 void nf_unregister_hook(struct nf_hook_ops *reg); 109 110 /* Functions to register get/setsockopt ranges (non-inclusive). You 111 need to check permissions yourself! */ 112 int nf_register_sockopt(struct nf_sockopt_ops *reg); 113 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 114 115 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 116 117 /* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will 118 * disappear once iptables is replaced with pkttables. Please DO NOT use them 119 * for any new code! */ 120 #define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */ 121 #define NF_LOG_TCPOPT 0x02 /* Log TCP options */ 122 #define NF_LOG_IPOPT 0x04 /* Log IP options */ 123 #define NF_LOG_UID 0x08 /* Log UID owning local socket */ 124 #define NF_LOG_MASK 0x0f 125 126 #define NF_LOG_TYPE_LOG 0x01 127 #define NF_LOG_TYPE_ULOG 0x02 128 129 struct nf_loginfo { 130 u_int8_t type; 131 union { 132 struct { 133 u_int32_t copy_len; 134 u_int16_t group; 135 u_int16_t qthreshold; 136 } ulog; 137 struct { 138 u_int8_t level; 139 u_int8_t logflags; 140 } log; 141 } u; 142 }; 143 144 typedef void nf_logfn(unsigned int pf, 145 unsigned int hooknum, 146 const struct sk_buff *skb, 147 const struct net_device *in, 148 const struct net_device *out, 149 const struct nf_loginfo *li, 150 const char *prefix); 151 152 struct nf_logger { 153 struct module *me; 154 nf_logfn *logfn; 155 char *name; 156 }; 157 158 /* Function to register/unregister log function. */ 159 int nf_log_register(int pf, struct nf_logger *logger); 160 int nf_log_unregister_pf(int pf); 161 void nf_log_unregister_logger(struct nf_logger *logger); 162 163 /* Calls the registered backend logging function */ 164 void nf_log_packet(int pf, 165 unsigned int hooknum, 166 const struct sk_buff *skb, 167 const struct net_device *in, 168 const struct net_device *out, 169 struct nf_loginfo *li, 170 const char *fmt, ...); 171 172 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb, 173 struct net_device *indev, struct net_device *outdev, 174 int (*okfn)(struct sk_buff *), int thresh); 175 176 /** 177 * nf_hook_thresh - call a netfilter hook 178 * 179 * Returns 1 if the hook has allowed the packet to pass. The function 180 * okfn must be invoked by the caller in this case. Any other return 181 * value indicates the packet has been consumed by the hook. 182 */ 183 static inline int nf_hook_thresh(int pf, unsigned int hook, 184 struct sk_buff **pskb, 185 struct net_device *indev, 186 struct net_device *outdev, 187 int (*okfn)(struct sk_buff *), int thresh, 188 int cond) 189 { 190 if (!cond) 191 return 1; 192 #ifndef CONFIG_NETFILTER_DEBUG 193 if (list_empty(&nf_hooks[pf][hook])) 194 return 1; 195 #endif 196 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh); 197 } 198 199 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 200 struct net_device *indev, struct net_device *outdev, 201 int (*okfn)(struct sk_buff *)) 202 { 203 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1); 204 } 205 206 /* Activate hook; either okfn or kfree_skb called, unless a hook 207 returns NF_STOLEN (in which case, it's up to the hook to deal with 208 the consequences). 209 210 Returns -ERRNO if packet dropped. Zero means queued, stolen or 211 accepted. 212 */ 213 214 /* RR: 215 > I don't want nf_hook to return anything because people might forget 216 > about async and trust the return value to mean "packet was ok". 217 218 AK: 219 Just document it clearly, then you can expect some sense from kernel 220 coders :) 221 */ 222 223 /* This is gross, but inline doesn't cut it for avoiding the function 224 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 225 226 /* HX: It's slightly less gross now. */ 227 228 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 229 ({int __ret; \ 230 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\ 231 __ret = (okfn)(skb); \ 232 __ret;}) 233 234 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 235 ({int __ret; \ 236 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 237 __ret = (okfn)(skb); \ 238 __ret;}) 239 240 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 241 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 242 243 /* Call setsockopt() */ 244 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 245 int len); 246 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 247 int *len); 248 249 /* Packet queuing */ 250 struct nf_queue_handler { 251 int (*outfn)(struct sk_buff *skb, struct nf_info *info, 252 unsigned int queuenum, void *data); 253 void *data; 254 char *name; 255 }; 256 extern int nf_register_queue_handler(int pf, 257 struct nf_queue_handler *qh); 258 extern int nf_unregister_queue_handler(int pf); 259 extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh); 260 extern void nf_reinject(struct sk_buff *skb, 261 struct nf_info *info, 262 unsigned int verdict); 263 264 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 265 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 266 267 /* FIXME: Before cache is ever used, this must be implemented for real. */ 268 extern void nf_invalidate_cache(int pf); 269 270 /* Call this before modifying an existing packet: ensures it is 271 modifiable and linear to the point you care about (writable_len). 272 Returns true or false. */ 273 extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len); 274 275 struct nf_queue_rerouter { 276 void (*save)(const struct sk_buff *skb, struct nf_info *info); 277 int (*reroute)(struct sk_buff **skb, const struct nf_info *info); 278 int rer_size; 279 }; 280 281 #define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info)) 282 283 extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer); 284 extern int nf_unregister_queue_rerouter(int pf); 285 286 #include <net/flow.h> 287 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 288 289 static inline void 290 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 291 { 292 #ifdef CONFIG_IP_NF_NAT_NEEDED 293 void (*decodefn)(struct sk_buff *, struct flowi *); 294 295 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 296 decodefn(skb, fl); 297 #endif 298 } 299 300 #ifdef CONFIG_PROC_FS 301 #include <linux/proc_fs.h> 302 extern struct proc_dir_entry *proc_net_netfilter; 303 #endif 304 305 #else /* !CONFIG_NETFILTER */ 306 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 307 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 308 static inline int nf_hook_thresh(int pf, unsigned int hook, 309 struct sk_buff **pskb, 310 struct net_device *indev, 311 struct net_device *outdev, 312 int (*okfn)(struct sk_buff *), int thresh, 313 int cond) 314 { 315 return okfn(*pskb); 316 } 317 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 318 struct net_device *indev, struct net_device *outdev, 319 int (*okfn)(struct sk_buff *)) 320 { 321 return 1; 322 } 323 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 324 struct flowi; 325 static inline void 326 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 327 #endif /*CONFIG_NETFILTER*/ 328 329 #endif /*__KERNEL__*/ 330 #endif /*__LINUX_NETFILTER_H*/ 331