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 /* Activate hook; either okfn or kfree_skb called, unless a hook 173 returns NF_STOLEN (in which case, it's up to the hook to deal with 174 the consequences). 175 176 Returns -ERRNO if packet dropped. Zero means queued, stolen or 177 accepted. 178 */ 179 180 /* RR: 181 > I don't want nf_hook to return anything because people might forget 182 > about async and trust the return value to mean "packet was ok". 183 184 AK: 185 Just document it clearly, then you can expect some sense from kernel 186 coders :) 187 */ 188 189 /* This is gross, but inline doesn't cut it for avoiding the function 190 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 191 #ifdef CONFIG_NETFILTER_DEBUG 192 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 193 ({int __ret; \ 194 if ((__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, INT_MIN)) == 1) \ 195 __ret = (okfn)(skb); \ 196 __ret;}) 197 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 198 ({int __ret; \ 199 if ((__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, thresh)) == 1) \ 200 __ret = (okfn)(skb); \ 201 __ret;}) 202 #else 203 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 204 ({int __ret; \ 205 if (list_empty(&nf_hooks[pf][hook]) || \ 206 (__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, INT_MIN)) == 1) \ 207 __ret = (okfn)(skb); \ 208 __ret;}) 209 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 210 ({int __ret; \ 211 if (list_empty(&nf_hooks[pf][hook]) || \ 212 (__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, thresh)) == 1) \ 213 __ret = (okfn)(skb); \ 214 __ret;}) 215 #endif 216 217 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb, 218 struct net_device *indev, struct net_device *outdev, 219 int (*okfn)(struct sk_buff *), int thresh); 220 221 /* Call setsockopt() */ 222 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 223 int len); 224 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 225 int *len); 226 227 /* Packet queuing */ 228 struct nf_queue_handler { 229 int (*outfn)(struct sk_buff *skb, struct nf_info *info, 230 unsigned int queuenum, void *data); 231 void *data; 232 char *name; 233 }; 234 extern int nf_register_queue_handler(int pf, 235 struct nf_queue_handler *qh); 236 extern int nf_unregister_queue_handler(int pf); 237 extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh); 238 extern void nf_reinject(struct sk_buff *skb, 239 struct nf_info *info, 240 unsigned int verdict); 241 242 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 243 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 244 245 /* FIXME: Before cache is ever used, this must be implemented for real. */ 246 extern void nf_invalidate_cache(int pf); 247 248 /* Call this before modifying an existing packet: ensures it is 249 modifiable and linear to the point you care about (writable_len). 250 Returns true or false. */ 251 extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len); 252 253 struct nf_queue_rerouter { 254 void (*save)(const struct sk_buff *skb, struct nf_info *info); 255 int (*reroute)(struct sk_buff **skb, const struct nf_info *info); 256 int rer_size; 257 }; 258 259 #define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info)) 260 261 extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer); 262 extern int nf_unregister_queue_rerouter(int pf); 263 264 #ifdef CONFIG_PROC_FS 265 #include <linux/proc_fs.h> 266 extern struct proc_dir_entry *proc_net_netfilter; 267 #endif 268 269 #else /* !CONFIG_NETFILTER */ 270 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 271 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 272 #endif /*CONFIG_NETFILTER*/ 273 274 #endif /*__KERNEL__*/ 275 #endif /*__LINUX_NETFILTER_H*/ 276