netfilter.h revision 23f3733d440b918ccb7746718f77256334cf6176
1#ifndef __LINUX_NETFILTER_H 2#define __LINUX_NETFILTER_H 3 4#ifdef __KERNEL__ 5#include <linux/init.h> 6#include <linux/skbuff.h> 7#include <linux/net.h> 8#include <linux/if.h> 9#include <linux/in.h> 10#include <linux/in6.h> 11#include <linux/wait.h> 12#include <linux/list.h> 13#endif 14#include <linux/types.h> 15#include <linux/compiler.h> 16 17/* Responses from hook functions. */ 18#define NF_DROP 0 19#define NF_ACCEPT 1 20#define NF_STOLEN 2 21#define NF_QUEUE 3 22#define NF_REPEAT 4 23#define NF_STOP 5 24#define NF_MAX_VERDICT NF_STOP 25 26/* we overload the higher bits for encoding auxiliary data such as the queue 27 * number. Not nice, but better than additional function arguments. */ 28#define NF_VERDICT_MASK 0x0000ffff 29#define NF_VERDICT_BITS 16 30 31#define NF_VERDICT_QMASK 0xffff0000 32#define NF_VERDICT_QBITS 16 33 34#define NF_QUEUE_NR(x) ((((x) << NF_VERDICT_BITS) & NF_VERDICT_QMASK) | NF_QUEUE) 35 36/* only for userspace compatibility */ 37#ifndef __KERNEL__ 38/* Generic cache responses from hook functions. 39 <= 0x2000 is used for protocol-flags. */ 40#define NFC_UNKNOWN 0x4000 41#define NFC_ALTERED 0x8000 42#endif 43 44enum nf_inet_hooks { 45 NF_INET_PRE_ROUTING, 46 NF_INET_LOCAL_IN, 47 NF_INET_FORWARD, 48 NF_INET_LOCAL_OUT, 49 NF_INET_POST_ROUTING, 50 NF_INET_NUMHOOKS 51}; 52 53enum { 54 NFPROTO_UNSPEC = 0, 55 NFPROTO_IPV4 = 2, 56 NFPROTO_ARP = 3, 57 NFPROTO_BRIDGE = 7, 58 NFPROTO_IPV6 = 10, 59 NFPROTO_DECNET = 12, 60 NFPROTO_NUMPROTO, 61}; 62 63union nf_inet_addr { 64 __u32 all[4]; 65 __be32 ip; 66 __be32 ip6[4]; 67 struct in_addr in; 68 struct in6_addr in6; 69}; 70 71#ifdef __KERNEL__ 72#ifdef CONFIG_NETFILTER 73 74static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 75 const union nf_inet_addr *a2) 76{ 77 return a1->all[0] == a2->all[0] && 78 a1->all[1] == a2->all[1] && 79 a1->all[2] == a2->all[2] && 80 a1->all[3] == a2->all[3]; 81} 82 83extern void netfilter_init(void); 84 85/* Largest hook number + 1 */ 86#define NF_MAX_HOOKS 8 87 88struct sk_buff; 89 90typedef unsigned int nf_hookfn(unsigned int hooknum, 91 struct sk_buff *skb, 92 const struct net_device *in, 93 const struct net_device *out, 94 int (*okfn)(struct sk_buff *)); 95 96struct nf_hook_ops { 97 struct list_head list; 98 99 /* User fills in from here down. */ 100 nf_hookfn *hook; 101 struct module *owner; 102 u_int8_t pf; 103 unsigned int hooknum; 104 /* Hooks are ordered in ascending priority. */ 105 int priority; 106}; 107 108struct nf_sockopt_ops { 109 struct list_head list; 110 111 u_int8_t pf; 112 113 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 114 int set_optmin; 115 int set_optmax; 116 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 117#ifdef CONFIG_COMPAT 118 int (*compat_set)(struct sock *sk, int optval, 119 void __user *user, unsigned int len); 120#endif 121 int get_optmin; 122 int get_optmax; 123 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 124#ifdef CONFIG_COMPAT 125 int (*compat_get)(struct sock *sk, int optval, 126 void __user *user, int *len); 127#endif 128 /* Use the module struct to lock set/get code in place */ 129 struct module *owner; 130}; 131 132/* Function to register/unregister hook points. */ 133int nf_register_hook(struct nf_hook_ops *reg); 134void nf_unregister_hook(struct nf_hook_ops *reg); 135int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 136void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 137 138/* Functions to register get/setsockopt ranges (non-inclusive). You 139 need to check permissions yourself! */ 140int nf_register_sockopt(struct nf_sockopt_ops *reg); 141void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 142 143#ifdef CONFIG_SYSCTL 144/* Sysctl registration */ 145extern struct ctl_path nf_net_netfilter_sysctl_path[]; 146extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; 147#endif /* CONFIG_SYSCTL */ 148 149extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 150 151int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 152 struct net_device *indev, struct net_device *outdev, 153 int (*okfn)(struct sk_buff *), int thresh); 154 155/** 156 * nf_hook_thresh - call a netfilter hook 157 * 158 * Returns 1 if the hook has allowed the packet to pass. The function 159 * okfn must be invoked by the caller in this case. Any other return 160 * value indicates the packet has been consumed by the hook. 161 */ 162static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 163 struct sk_buff *skb, 164 struct net_device *indev, 165 struct net_device *outdev, 166 int (*okfn)(struct sk_buff *), int thresh) 167{ 168#ifndef CONFIG_NETFILTER_DEBUG 169 if (list_empty(&nf_hooks[pf][hook])) 170 return 1; 171#endif 172 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 173} 174 175static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 176 struct net_device *indev, struct net_device *outdev, 177 int (*okfn)(struct sk_buff *)) 178{ 179 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN); 180} 181 182/* Activate hook; either okfn or kfree_skb called, unless a hook 183 returns NF_STOLEN (in which case, it's up to the hook to deal with 184 the consequences). 185 186 Returns -ERRNO if packet dropped. Zero means queued, stolen or 187 accepted. 188*/ 189 190/* RR: 191 > I don't want nf_hook to return anything because people might forget 192 > about async and trust the return value to mean "packet was ok". 193 194 AK: 195 Just document it clearly, then you can expect some sense from kernel 196 coders :) 197*/ 198 199/* This is gross, but inline doesn't cut it for avoiding the function 200 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 201 202/* HX: It's slightly less gross now. */ 203 204#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 205({int __ret; \ 206if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh)) == 1)\ 207 __ret = (okfn)(skb); \ 208__ret;}) 209 210#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 211({int __ret; \ 212if ((cond) || (__ret = nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN)) == 1)\ 213 __ret = (okfn)(skb); \ 214__ret;}) 215 216#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 217 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 218 219/* Call setsockopt() */ 220int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 221 unsigned int len); 222int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 223 int *len); 224#ifdef CONFIG_COMPAT 225int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 226 char __user *opt, unsigned int len); 227int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 228 char __user *opt, int *len); 229#endif 230 231/* Call this before modifying an existing packet: ensures it is 232 modifiable and linear to the point you care about (writable_len). 233 Returns true or false. */ 234extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 235 236struct flowi; 237struct nf_queue_entry; 238 239struct nf_afinfo { 240 unsigned short family; 241 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 242 unsigned int dataoff, u_int8_t protocol); 243 __sum16 (*checksum_partial)(struct sk_buff *skb, 244 unsigned int hook, 245 unsigned int dataoff, 246 unsigned int len, 247 u_int8_t protocol); 248 int (*route)(struct dst_entry **dst, struct flowi *fl); 249 void (*saveroute)(const struct sk_buff *skb, 250 struct nf_queue_entry *entry); 251 int (*reroute)(struct sk_buff *skb, 252 const struct nf_queue_entry *entry); 253 int route_key_size; 254}; 255 256extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO]; 257static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 258{ 259 return rcu_dereference(nf_afinfo[family]); 260} 261 262static inline __sum16 263nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 264 u_int8_t protocol, unsigned short family) 265{ 266 const struct nf_afinfo *afinfo; 267 __sum16 csum = 0; 268 269 rcu_read_lock(); 270 afinfo = nf_get_afinfo(family); 271 if (afinfo) 272 csum = afinfo->checksum(skb, hook, dataoff, protocol); 273 rcu_read_unlock(); 274 return csum; 275} 276 277static inline __sum16 278nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 279 unsigned int dataoff, unsigned int len, 280 u_int8_t protocol, unsigned short family) 281{ 282 const struct nf_afinfo *afinfo; 283 __sum16 csum = 0; 284 285 rcu_read_lock(); 286 afinfo = nf_get_afinfo(family); 287 if (afinfo) 288 csum = afinfo->checksum_partial(skb, hook, dataoff, len, 289 protocol); 290 rcu_read_unlock(); 291 return csum; 292} 293 294extern int nf_register_afinfo(const struct nf_afinfo *afinfo); 295extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 296 297#include <net/flow.h> 298extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 299 300static inline void 301nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 302{ 303#ifdef CONFIG_NF_NAT_NEEDED 304 void (*decodefn)(struct sk_buff *, struct flowi *); 305 306 if (family == AF_INET) { 307 rcu_read_lock(); 308 decodefn = rcu_dereference(ip_nat_decode_session); 309 if (decodefn) 310 decodefn(skb, fl); 311 rcu_read_unlock(); 312 } 313#endif 314} 315 316#ifdef CONFIG_PROC_FS 317#include <linux/proc_fs.h> 318extern struct proc_dir_entry *proc_net_netfilter; 319#endif 320 321#else /* !CONFIG_NETFILTER */ 322#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 323#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 324static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 325 struct sk_buff *skb, 326 struct net_device *indev, 327 struct net_device *outdev, 328 int (*okfn)(struct sk_buff *), int thresh) 329{ 330 return okfn(skb); 331} 332static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 333 struct net_device *indev, struct net_device *outdev, 334 int (*okfn)(struct sk_buff *)) 335{ 336 return 1; 337} 338struct flowi; 339static inline void 340nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 341{ 342} 343#endif /*CONFIG_NETFILTER*/ 344 345#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 346extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 347extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 348extern void (*nf_ct_destroy)(struct nf_conntrack *); 349#else 350static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 351#endif 352 353#endif /*__KERNEL__*/ 354#endif /*__LINUX_NETFILTER_H*/ 355