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#ifdef CONFIG_NETFILTER 44 45extern void netfilter_init(void); 46 47/* Largest hook number + 1 */ 48#define NF_MAX_HOOKS 8 49 50struct sk_buff; 51struct net_device; 52 53typedef unsigned int nf_hookfn(unsigned int hooknum, 54 struct sk_buff **skb, 55 const struct net_device *in, 56 const struct net_device *out, 57 int (*okfn)(struct sk_buff *)); 58 59struct nf_hook_ops 60{ 61 struct list_head list; 62 63 /* User fills in from here down. */ 64 nf_hookfn *hook; 65 struct module *owner; 66 int pf; 67 int hooknum; 68 /* Hooks are ordered in ascending priority. */ 69 int priority; 70}; 71 72struct nf_sockopt_ops 73{ 74 struct list_head list; 75 76 int pf; 77 78 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 79 int set_optmin; 80 int set_optmax; 81 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 82 int (*compat_set)(struct sock *sk, int optval, 83 void __user *user, unsigned int len); 84 85 int get_optmin; 86 int get_optmax; 87 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 88 int (*compat_get)(struct sock *sk, int optval, 89 void __user *user, int *len); 90 91 /* Number of users inside set() or get(). */ 92 unsigned int use; 93 struct task_struct *cleanup_task; 94}; 95 96/* Each queued (to userspace) skbuff has one of these. */ 97struct nf_info 98{ 99 /* The ops struct which sent us to userspace. */ 100 struct nf_hook_ops *elem; 101 102 /* If we're sent to userspace, this keeps housekeeping info */ 103 int pf; 104 unsigned int hook; 105 struct net_device *indev, *outdev; 106 int (*okfn)(struct sk_buff *); 107}; 108 109/* Function to register/unregister hook points. */ 110int nf_register_hook(struct nf_hook_ops *reg); 111void nf_unregister_hook(struct nf_hook_ops *reg); 112int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 113void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 114 115/* Functions to register get/setsockopt ranges (non-inclusive). You 116 need to check permissions yourself! */ 117int nf_register_sockopt(struct nf_sockopt_ops *reg); 118void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 119 120#ifdef CONFIG_SYSCTL 121/* Sysctl registration */ 122struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path, 123 struct ctl_table *table); 124void nf_unregister_sysctl_table(struct ctl_table_header *header, 125 struct ctl_table *table); 126extern struct ctl_table nf_net_netfilter_sysctl_path[]; 127extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[]; 128#endif /* CONFIG_SYSCTL */ 129 130extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 131 132/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will 133 * disappear once iptables is replaced with pkttables. Please DO NOT use them 134 * for any new code! */ 135#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */ 136#define NF_LOG_TCPOPT 0x02 /* Log TCP options */ 137#define NF_LOG_IPOPT 0x04 /* Log IP options */ 138#define NF_LOG_UID 0x08 /* Log UID owning local socket */ 139#define NF_LOG_MASK 0x0f 140 141#define NF_LOG_TYPE_LOG 0x01 142#define NF_LOG_TYPE_ULOG 0x02 143 144struct nf_loginfo { 145 u_int8_t type; 146 union { 147 struct { 148 u_int32_t copy_len; 149 u_int16_t group; 150 u_int16_t qthreshold; 151 } ulog; 152 struct { 153 u_int8_t level; 154 u_int8_t logflags; 155 } log; 156 } u; 157}; 158 159typedef void nf_logfn(unsigned int pf, 160 unsigned int hooknum, 161 const struct sk_buff *skb, 162 const struct net_device *in, 163 const struct net_device *out, 164 const struct nf_loginfo *li, 165 const char *prefix); 166 167struct nf_logger { 168 struct module *me; 169 nf_logfn *logfn; 170 char *name; 171}; 172 173/* Function to register/unregister log function. */ 174int nf_log_register(int pf, struct nf_logger *logger); 175void nf_log_unregister(struct nf_logger *logger); 176void nf_log_unregister_pf(int pf); 177 178/* Calls the registered backend logging function */ 179void nf_log_packet(int pf, 180 unsigned int hooknum, 181 const struct sk_buff *skb, 182 const struct net_device *in, 183 const struct net_device *out, 184 struct nf_loginfo *li, 185 const char *fmt, ...); 186 187int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb, 188 struct net_device *indev, struct net_device *outdev, 189 int (*okfn)(struct sk_buff *), int thresh); 190 191/** 192 * nf_hook_thresh - call a netfilter hook 193 * 194 * Returns 1 if the hook has allowed the packet to pass. The function 195 * okfn must be invoked by the caller in this case. Any other return 196 * value indicates the packet has been consumed by the hook. 197 */ 198static inline int nf_hook_thresh(int pf, unsigned int hook, 199 struct sk_buff **pskb, 200 struct net_device *indev, 201 struct net_device *outdev, 202 int (*okfn)(struct sk_buff *), int thresh, 203 int cond) 204{ 205 if (!cond) 206 return 1; 207#ifndef CONFIG_NETFILTER_DEBUG 208 if (list_empty(&nf_hooks[pf][hook])) 209 return 1; 210#endif 211 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh); 212} 213 214static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 215 struct net_device *indev, struct net_device *outdev, 216 int (*okfn)(struct sk_buff *)) 217{ 218 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1); 219} 220 221/* Activate hook; either okfn or kfree_skb called, unless a hook 222 returns NF_STOLEN (in which case, it's up to the hook to deal with 223 the consequences). 224 225 Returns -ERRNO if packet dropped. Zero means queued, stolen or 226 accepted. 227*/ 228 229/* RR: 230 > I don't want nf_hook to return anything because people might forget 231 > about async and trust the return value to mean "packet was ok". 232 233 AK: 234 Just document it clearly, then you can expect some sense from kernel 235 coders :) 236*/ 237 238/* This is gross, but inline doesn't cut it for avoiding the function 239 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 240 241/* HX: It's slightly less gross now. */ 242 243#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 244({int __ret; \ 245if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\ 246 __ret = (okfn)(skb); \ 247__ret;}) 248 249#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 250({int __ret; \ 251if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 252 __ret = (okfn)(skb); \ 253__ret;}) 254 255#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 256 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 257 258/* Call setsockopt() */ 259int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 260 int len); 261int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 262 int *len); 263 264int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 265 char __user *opt, int len); 266int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 267 char __user *opt, int *len); 268 269/* Packet queuing */ 270struct nf_queue_handler { 271 int (*outfn)(struct sk_buff *skb, struct nf_info *info, 272 unsigned int queuenum, void *data); 273 void *data; 274 char *name; 275}; 276extern int nf_register_queue_handler(int pf, 277 struct nf_queue_handler *qh); 278extern int nf_unregister_queue_handler(int pf); 279extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh); 280extern void nf_reinject(struct sk_buff *skb, 281 struct nf_info *info, 282 unsigned int verdict); 283 284extern void nf_invalidate_cache(int pf); 285 286/* Call this before modifying an existing packet: ensures it is 287 modifiable and linear to the point you care about (writable_len). 288 Returns true or false. */ 289extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len); 290 291static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to) 292{ 293 __be32 diff[] = { ~from, to }; 294 295 *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum))); 296} 297 298static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to) 299{ 300 nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to); 301} 302 303extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, 304 __be32 from, __be32 to, int pseudohdr); 305 306static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, 307 __be16 from, __be16 to, int pseudohdr) 308{ 309 nf_proto_csum_replace4(sum, skb, (__force __be32)from, 310 (__force __be32)to, pseudohdr); 311} 312 313struct nf_afinfo { 314 unsigned short family; 315 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 316 unsigned int dataoff, u_int8_t protocol); 317 void (*saveroute)(const struct sk_buff *skb, 318 struct nf_info *info); 319 int (*reroute)(struct sk_buff **skb, 320 const struct nf_info *info); 321 int route_key_size; 322}; 323 324extern struct nf_afinfo *nf_afinfo[]; 325static inline struct nf_afinfo *nf_get_afinfo(unsigned short family) 326{ 327 return rcu_dereference(nf_afinfo[family]); 328} 329 330static inline __sum16 331nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 332 u_int8_t protocol, unsigned short family) 333{ 334 struct nf_afinfo *afinfo; 335 __sum16 csum = 0; 336 337 rcu_read_lock(); 338 afinfo = nf_get_afinfo(family); 339 if (afinfo) 340 csum = afinfo->checksum(skb, hook, dataoff, protocol); 341 rcu_read_unlock(); 342 return csum; 343} 344 345extern int nf_register_afinfo(struct nf_afinfo *afinfo); 346extern void nf_unregister_afinfo(struct nf_afinfo *afinfo); 347 348#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info)) 349 350#include <net/flow.h> 351extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 352 353static inline void 354nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 355{ 356#if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED) 357 void (*decodefn)(struct sk_buff *, struct flowi *); 358 359 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 360 decodefn(skb, fl); 361#endif 362} 363 364#ifdef CONFIG_PROC_FS 365#include <linux/proc_fs.h> 366extern struct proc_dir_entry *proc_net_netfilter; 367#endif 368 369#else /* !CONFIG_NETFILTER */ 370#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 371#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 372static inline int nf_hook_thresh(int pf, unsigned int hook, 373 struct sk_buff **pskb, 374 struct net_device *indev, 375 struct net_device *outdev, 376 int (*okfn)(struct sk_buff *), int thresh, 377 int cond) 378{ 379 return okfn(*pskb); 380} 381static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 382 struct net_device *indev, struct net_device *outdev, 383 int (*okfn)(struct sk_buff *)) 384{ 385 return 1; 386} 387struct flowi; 388static inline void 389nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 390#endif /*CONFIG_NETFILTER*/ 391 392#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 393extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 394extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 395extern void (*nf_ct_destroy)(struct nf_conntrack *); 396#else 397static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 398#endif 399 400#endif /*__KERNEL__*/ 401#endif /*__LINUX_NETFILTER_H*/ 402