netfilter.h revision 6e23ae2a48750bda407a4a58f52a4865d7308bf5
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/* Each queued (to userspace) skbuff has one of these. */ 105struct nf_info 106{ 107 /* The ops struct which sent us to userspace. */ 108 struct nf_hook_ops *elem; 109 110 /* If we're sent to userspace, this keeps housekeeping info */ 111 int pf; 112 unsigned int hook; 113 struct net_device *indev, *outdev; 114 int (*okfn)(struct sk_buff *); 115}; 116 117/* Function to register/unregister hook points. */ 118int nf_register_hook(struct nf_hook_ops *reg); 119void nf_unregister_hook(struct nf_hook_ops *reg); 120int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 121void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 122 123/* Functions to register get/setsockopt ranges (non-inclusive). You 124 need to check permissions yourself! */ 125int nf_register_sockopt(struct nf_sockopt_ops *reg); 126void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 127 128#ifdef CONFIG_SYSCTL 129/* Sysctl registration */ 130struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path, 131 struct ctl_table *table); 132void nf_unregister_sysctl_table(struct ctl_table_header *header, 133 struct ctl_table *table); 134extern struct ctl_table nf_net_netfilter_sysctl_path[]; 135extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[]; 136#endif /* CONFIG_SYSCTL */ 137 138extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 139 140/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will 141 * disappear once iptables is replaced with pkttables. Please DO NOT use them 142 * for any new code! */ 143#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */ 144#define NF_LOG_TCPOPT 0x02 /* Log TCP options */ 145#define NF_LOG_IPOPT 0x04 /* Log IP options */ 146#define NF_LOG_UID 0x08 /* Log UID owning local socket */ 147#define NF_LOG_MASK 0x0f 148 149#define NF_LOG_TYPE_LOG 0x01 150#define NF_LOG_TYPE_ULOG 0x02 151 152struct nf_loginfo { 153 u_int8_t type; 154 union { 155 struct { 156 u_int32_t copy_len; 157 u_int16_t group; 158 u_int16_t qthreshold; 159 } ulog; 160 struct { 161 u_int8_t level; 162 u_int8_t logflags; 163 } log; 164 } u; 165}; 166 167typedef void nf_logfn(unsigned int pf, 168 unsigned int hooknum, 169 const struct sk_buff *skb, 170 const struct net_device *in, 171 const struct net_device *out, 172 const struct nf_loginfo *li, 173 const char *prefix); 174 175struct nf_logger { 176 struct module *me; 177 nf_logfn *logfn; 178 char *name; 179}; 180 181/* Function to register/unregister log function. */ 182int nf_log_register(int pf, struct nf_logger *logger); 183void nf_log_unregister(struct nf_logger *logger); 184void nf_log_unregister_pf(int pf); 185 186/* Calls the registered backend logging function */ 187void nf_log_packet(int pf, 188 unsigned int hooknum, 189 const struct sk_buff *skb, 190 const struct net_device *in, 191 const struct net_device *out, 192 struct nf_loginfo *li, 193 const char *fmt, ...); 194 195int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb, 196 struct net_device *indev, struct net_device *outdev, 197 int (*okfn)(struct sk_buff *), int thresh); 198 199/** 200 * nf_hook_thresh - call a netfilter hook 201 * 202 * Returns 1 if the hook has allowed the packet to pass. The function 203 * okfn must be invoked by the caller in this case. Any other return 204 * value indicates the packet has been consumed by the hook. 205 */ 206static inline int nf_hook_thresh(int pf, unsigned int hook, 207 struct sk_buff *skb, 208 struct net_device *indev, 209 struct net_device *outdev, 210 int (*okfn)(struct sk_buff *), int thresh, 211 int cond) 212{ 213 if (!cond) 214 return 1; 215#ifndef CONFIG_NETFILTER_DEBUG 216 if (list_empty(&nf_hooks[pf][hook])) 217 return 1; 218#endif 219 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 220} 221 222static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 223 struct net_device *indev, struct net_device *outdev, 224 int (*okfn)(struct sk_buff *)) 225{ 226 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1); 227} 228 229/* Activate hook; either okfn or kfree_skb called, unless a hook 230 returns NF_STOLEN (in which case, it's up to the hook to deal with 231 the consequences). 232 233 Returns -ERRNO if packet dropped. Zero means queued, stolen or 234 accepted. 235*/ 236 237/* RR: 238 > I don't want nf_hook to return anything because people might forget 239 > about async and trust the return value to mean "packet was ok". 240 241 AK: 242 Just document it clearly, then you can expect some sense from kernel 243 coders :) 244*/ 245 246/* This is gross, but inline doesn't cut it for avoiding the function 247 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 248 249/* HX: It's slightly less gross now. */ 250 251#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 252({int __ret; \ 253if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\ 254 __ret = (okfn)(skb); \ 255__ret;}) 256 257#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 258({int __ret; \ 259if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 260 __ret = (okfn)(skb); \ 261__ret;}) 262 263#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 264 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 265 266/* Call setsockopt() */ 267int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 268 int len); 269int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 270 int *len); 271 272int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 273 char __user *opt, int len); 274int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 275 char __user *opt, int *len); 276 277/* Packet queuing */ 278struct nf_queue_handler { 279 int (*outfn)(struct sk_buff *skb, struct nf_info *info, 280 unsigned int queuenum, void *data); 281 void *data; 282 char *name; 283}; 284extern int nf_register_queue_handler(int pf, 285 struct nf_queue_handler *qh); 286extern int nf_unregister_queue_handler(int pf, 287 struct nf_queue_handler *qh); 288extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh); 289extern void nf_reinject(struct sk_buff *skb, 290 struct nf_info *info, 291 unsigned int verdict); 292 293/* FIXME: Before cache is ever used, this must be implemented for real. */ 294extern void nf_invalidate_cache(int pf); 295 296/* Call this before modifying an existing packet: ensures it is 297 modifiable and linear to the point you care about (writable_len). 298 Returns true or false. */ 299extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 300 301static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to) 302{ 303 __be32 diff[] = { ~from, to }; 304 305 *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum))); 306} 307 308static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to) 309{ 310 nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to); 311} 312 313extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, 314 __be32 from, __be32 to, int pseudohdr); 315 316static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, 317 __be16 from, __be16 to, int pseudohdr) 318{ 319 nf_proto_csum_replace4(sum, skb, (__force __be32)from, 320 (__force __be32)to, pseudohdr); 321} 322 323struct nf_afinfo { 324 unsigned short family; 325 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 326 unsigned int dataoff, u_int8_t protocol); 327 void (*saveroute)(const struct sk_buff *skb, 328 struct nf_info *info); 329 int (*reroute)(struct sk_buff *skb, 330 const struct nf_info *info); 331 int route_key_size; 332}; 333 334extern struct nf_afinfo *nf_afinfo[]; 335static inline struct nf_afinfo *nf_get_afinfo(unsigned short family) 336{ 337 return rcu_dereference(nf_afinfo[family]); 338} 339 340static inline __sum16 341nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 342 u_int8_t protocol, unsigned short family) 343{ 344 struct nf_afinfo *afinfo; 345 __sum16 csum = 0; 346 347 rcu_read_lock(); 348 afinfo = nf_get_afinfo(family); 349 if (afinfo) 350 csum = afinfo->checksum(skb, hook, dataoff, protocol); 351 rcu_read_unlock(); 352 return csum; 353} 354 355extern int nf_register_afinfo(struct nf_afinfo *afinfo); 356extern void nf_unregister_afinfo(struct nf_afinfo *afinfo); 357 358#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info)) 359 360#include <net/flow.h> 361extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 362 363static inline void 364nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 365{ 366#if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED) 367 void (*decodefn)(struct sk_buff *, struct flowi *); 368 369 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 370 decodefn(skb, fl); 371#endif 372} 373 374#ifdef CONFIG_PROC_FS 375#include <linux/proc_fs.h> 376extern struct proc_dir_entry *proc_net_netfilter; 377#endif 378 379#else /* !CONFIG_NETFILTER */ 380#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 381#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 382static inline int nf_hook_thresh(int pf, unsigned int hook, 383 struct sk_buff *skb, 384 struct net_device *indev, 385 struct net_device *outdev, 386 int (*okfn)(struct sk_buff *), int thresh, 387 int cond) 388{ 389 return okfn(skb); 390} 391static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 392 struct net_device *indev, struct net_device *outdev, 393 int (*okfn)(struct sk_buff *)) 394{ 395 return 1; 396} 397struct flowi; 398static inline void 399nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 400#endif /*CONFIG_NETFILTER*/ 401 402#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 403extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 404extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 405extern void (*nf_ct_destroy)(struct nf_conntrack *); 406#else 407static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 408#endif 409 410#endif /*__KERNEL__*/ 411#endif /*__LINUX_NETFILTER_H*/ 412