netfilter.h revision c01cd429fc118c5db92475c5f08b307718aa4efc
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 42enum nf_inet_hooks { 43 NF_INET_PRE_ROUTING, 44 NF_INET_LOCAL_IN, 45 NF_INET_FORWARD, 46 NF_INET_LOCAL_OUT, 47 NF_INET_POST_ROUTING, 48 NF_INET_NUMHOOKS 49}; 50 51#ifdef __KERNEL__ 52#ifdef CONFIG_NETFILTER 53 54extern void netfilter_init(void); 55 56/* Largest hook number + 1 */ 57#define NF_MAX_HOOKS 8 58 59struct sk_buff; 60struct net_device; 61 62typedef unsigned int nf_hookfn(unsigned int hooknum, 63 struct sk_buff *skb, 64 const struct net_device *in, 65 const struct net_device *out, 66 int (*okfn)(struct sk_buff *)); 67 68struct nf_hook_ops 69{ 70 struct list_head list; 71 72 /* User fills in from here down. */ 73 nf_hookfn *hook; 74 struct module *owner; 75 int pf; 76 int hooknum; 77 /* Hooks are ordered in ascending priority. */ 78 int priority; 79}; 80 81struct nf_sockopt_ops 82{ 83 struct list_head list; 84 85 int pf; 86 87 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 88 int set_optmin; 89 int set_optmax; 90 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 91 int (*compat_set)(struct sock *sk, int optval, 92 void __user *user, unsigned int len); 93 94 int get_optmin; 95 int get_optmax; 96 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 97 int (*compat_get)(struct sock *sk, int optval, 98 void __user *user, int *len); 99 100 /* Use the module struct to lock set/get code in place */ 101 struct module *owner; 102}; 103 104/* Function to register/unregister hook points. */ 105int nf_register_hook(struct nf_hook_ops *reg); 106void nf_unregister_hook(struct nf_hook_ops *reg); 107int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 108void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 109 110/* Functions to register get/setsockopt ranges (non-inclusive). You 111 need to check permissions yourself! */ 112int nf_register_sockopt(struct nf_sockopt_ops *reg); 113void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 114 115#ifdef CONFIG_SYSCTL 116/* Sysctl registration */ 117struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path, 118 struct ctl_table *table); 119void nf_unregister_sysctl_table(struct ctl_table_header *header, 120 struct ctl_table *table); 121extern struct ctl_table nf_net_netfilter_sysctl_path[]; 122extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[]; 123#endif /* CONFIG_SYSCTL */ 124 125extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 126 127/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will 128 * disappear once iptables is replaced with pkttables. Please DO NOT use them 129 * for any new code! */ 130#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */ 131#define NF_LOG_TCPOPT 0x02 /* Log TCP options */ 132#define NF_LOG_IPOPT 0x04 /* Log IP options */ 133#define NF_LOG_UID 0x08 /* Log UID owning local socket */ 134#define NF_LOG_MASK 0x0f 135 136#define NF_LOG_TYPE_LOG 0x01 137#define NF_LOG_TYPE_ULOG 0x02 138 139struct nf_loginfo { 140 u_int8_t type; 141 union { 142 struct { 143 u_int32_t copy_len; 144 u_int16_t group; 145 u_int16_t qthreshold; 146 } ulog; 147 struct { 148 u_int8_t level; 149 u_int8_t logflags; 150 } log; 151 } u; 152}; 153 154typedef void nf_logfn(unsigned int pf, 155 unsigned int hooknum, 156 const struct sk_buff *skb, 157 const struct net_device *in, 158 const struct net_device *out, 159 const struct nf_loginfo *li, 160 const char *prefix); 161 162struct nf_logger { 163 struct module *me; 164 nf_logfn *logfn; 165 char *name; 166}; 167 168/* Function to register/unregister log function. */ 169int nf_log_register(int pf, struct nf_logger *logger); 170void nf_log_unregister(struct nf_logger *logger); 171void nf_log_unregister_pf(int pf); 172 173/* Calls the registered backend logging function */ 174void nf_log_packet(int pf, 175 unsigned int hooknum, 176 const struct sk_buff *skb, 177 const struct net_device *in, 178 const struct net_device *out, 179 struct nf_loginfo *li, 180 const char *fmt, ...); 181 182int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb, 183 struct net_device *indev, struct net_device *outdev, 184 int (*okfn)(struct sk_buff *), int thresh); 185 186/** 187 * nf_hook_thresh - call a netfilter hook 188 * 189 * Returns 1 if the hook has allowed the packet to pass. The function 190 * okfn must be invoked by the caller in this case. Any other return 191 * value indicates the packet has been consumed by the hook. 192 */ 193static inline int nf_hook_thresh(int pf, unsigned int hook, 194 struct sk_buff *skb, 195 struct net_device *indev, 196 struct net_device *outdev, 197 int (*okfn)(struct sk_buff *), int thresh, 198 int cond) 199{ 200 if (!cond) 201 return 1; 202#ifndef CONFIG_NETFILTER_DEBUG 203 if (list_empty(&nf_hooks[pf][hook])) 204 return 1; 205#endif 206 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 207} 208 209static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 210 struct net_device *indev, struct net_device *outdev, 211 int (*okfn)(struct sk_buff *)) 212{ 213 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1); 214} 215 216/* Activate hook; either okfn or kfree_skb called, unless a hook 217 returns NF_STOLEN (in which case, it's up to the hook to deal with 218 the consequences). 219 220 Returns -ERRNO if packet dropped. Zero means queued, stolen or 221 accepted. 222*/ 223 224/* RR: 225 > I don't want nf_hook to return anything because people might forget 226 > about async and trust the return value to mean "packet was ok". 227 228 AK: 229 Just document it clearly, then you can expect some sense from kernel 230 coders :) 231*/ 232 233/* This is gross, but inline doesn't cut it for avoiding the function 234 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 235 236/* HX: It's slightly less gross now. */ 237 238#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 239({int __ret; \ 240if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\ 241 __ret = (okfn)(skb); \ 242__ret;}) 243 244#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 245({int __ret; \ 246if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 247 __ret = (okfn)(skb); \ 248__ret;}) 249 250#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 251 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 252 253/* Call setsockopt() */ 254int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 255 int len); 256int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 257 int *len); 258 259int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 260 char __user *opt, int len); 261int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 262 char __user *opt, int *len); 263 264/* FIXME: Before cache is ever used, this must be implemented for real. */ 265extern void nf_invalidate_cache(int pf); 266 267/* Call this before modifying an existing packet: ensures it is 268 modifiable and linear to the point you care about (writable_len). 269 Returns true or false. */ 270extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 271 272struct flowi; 273struct nf_info; 274 275struct nf_afinfo { 276 unsigned short family; 277 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 278 unsigned int dataoff, u_int8_t protocol); 279 int (*route)(struct dst_entry **dst, struct flowi *fl); 280 void (*saveroute)(const struct sk_buff *skb, 281 struct nf_info *info); 282 int (*reroute)(struct sk_buff *skb, 283 const struct nf_info *info); 284 int route_key_size; 285}; 286 287extern struct nf_afinfo *nf_afinfo[]; 288static inline struct nf_afinfo *nf_get_afinfo(unsigned short family) 289{ 290 return rcu_dereference(nf_afinfo[family]); 291} 292 293static inline __sum16 294nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 295 u_int8_t protocol, unsigned short family) 296{ 297 struct nf_afinfo *afinfo; 298 __sum16 csum = 0; 299 300 rcu_read_lock(); 301 afinfo = nf_get_afinfo(family); 302 if (afinfo) 303 csum = afinfo->checksum(skb, hook, dataoff, protocol); 304 rcu_read_unlock(); 305 return csum; 306} 307 308extern int nf_register_afinfo(struct nf_afinfo *afinfo); 309extern void nf_unregister_afinfo(struct nf_afinfo *afinfo); 310 311#include <net/flow.h> 312extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 313 314static inline void 315nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 316{ 317#if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED) 318 void (*decodefn)(struct sk_buff *, struct flowi *); 319 320 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 321 decodefn(skb, fl); 322#endif 323} 324 325#ifdef CONFIG_PROC_FS 326#include <linux/proc_fs.h> 327extern struct proc_dir_entry *proc_net_netfilter; 328#endif 329 330#else /* !CONFIG_NETFILTER */ 331#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 332#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 333static inline int nf_hook_thresh(int pf, unsigned int hook, 334 struct sk_buff *skb, 335 struct net_device *indev, 336 struct net_device *outdev, 337 int (*okfn)(struct sk_buff *), int thresh, 338 int cond) 339{ 340 return okfn(skb); 341} 342static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 343 struct net_device *indev, struct net_device *outdev, 344 int (*okfn)(struct sk_buff *)) 345{ 346 return 1; 347} 348struct flowi; 349static inline void 350nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 351#endif /*CONFIG_NETFILTER*/ 352 353#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 354extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 355extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 356extern void (*nf_ct_destroy)(struct nf_conntrack *); 357#else 358static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 359#endif 360 361#endif /*__KERNEL__*/ 362#endif /*__LINUX_NETFILTER_H*/ 363