netfilter.h revision f01ffbd6e7d001ccf9168b33507958a51ce0ffcf
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 127int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb, 128 struct net_device *indev, struct net_device *outdev, 129 int (*okfn)(struct sk_buff *), int thresh); 130 131/** 132 * nf_hook_thresh - call a netfilter hook 133 * 134 * Returns 1 if the hook has allowed the packet to pass. The function 135 * okfn must be invoked by the caller in this case. Any other return 136 * value indicates the packet has been consumed by the hook. 137 */ 138static inline int nf_hook_thresh(int pf, unsigned int hook, 139 struct sk_buff *skb, 140 struct net_device *indev, 141 struct net_device *outdev, 142 int (*okfn)(struct sk_buff *), int thresh, 143 int cond) 144{ 145 if (!cond) 146 return 1; 147#ifndef CONFIG_NETFILTER_DEBUG 148 if (list_empty(&nf_hooks[pf][hook])) 149 return 1; 150#endif 151 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 152} 153 154static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 155 struct net_device *indev, struct net_device *outdev, 156 int (*okfn)(struct sk_buff *)) 157{ 158 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1); 159} 160 161/* Activate hook; either okfn or kfree_skb called, unless a hook 162 returns NF_STOLEN (in which case, it's up to the hook to deal with 163 the consequences). 164 165 Returns -ERRNO if packet dropped. Zero means queued, stolen or 166 accepted. 167*/ 168 169/* RR: 170 > I don't want nf_hook to return anything because people might forget 171 > about async and trust the return value to mean "packet was ok". 172 173 AK: 174 Just document it clearly, then you can expect some sense from kernel 175 coders :) 176*/ 177 178/* This is gross, but inline doesn't cut it for avoiding the function 179 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 180 181/* HX: It's slightly less gross now. */ 182 183#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 184({int __ret; \ 185if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\ 186 __ret = (okfn)(skb); \ 187__ret;}) 188 189#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 190({int __ret; \ 191if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 192 __ret = (okfn)(skb); \ 193__ret;}) 194 195#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 196 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 197 198/* Call setsockopt() */ 199int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 200 int len); 201int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 202 int *len); 203 204int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 205 char __user *opt, int len); 206int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 207 char __user *opt, int *len); 208 209/* FIXME: Before cache is ever used, this must be implemented for real. */ 210extern void nf_invalidate_cache(int pf); 211 212/* Call this before modifying an existing packet: ensures it is 213 modifiable and linear to the point you care about (writable_len). 214 Returns true or false. */ 215extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 216 217struct flowi; 218struct nf_queue_entry; 219 220struct nf_afinfo { 221 unsigned short family; 222 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 223 unsigned int dataoff, u_int8_t protocol); 224 int (*route)(struct dst_entry **dst, struct flowi *fl); 225 void (*saveroute)(const struct sk_buff *skb, 226 struct nf_queue_entry *entry); 227 int (*reroute)(struct sk_buff *skb, 228 const struct nf_queue_entry *entry); 229 int route_key_size; 230}; 231 232extern struct nf_afinfo *nf_afinfo[]; 233static inline struct nf_afinfo *nf_get_afinfo(unsigned short family) 234{ 235 return rcu_dereference(nf_afinfo[family]); 236} 237 238static inline __sum16 239nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 240 u_int8_t protocol, unsigned short family) 241{ 242 struct nf_afinfo *afinfo; 243 __sum16 csum = 0; 244 245 rcu_read_lock(); 246 afinfo = nf_get_afinfo(family); 247 if (afinfo) 248 csum = afinfo->checksum(skb, hook, dataoff, protocol); 249 rcu_read_unlock(); 250 return csum; 251} 252 253extern int nf_register_afinfo(struct nf_afinfo *afinfo); 254extern void nf_unregister_afinfo(struct nf_afinfo *afinfo); 255 256#include <net/flow.h> 257extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 258 259static inline void 260nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 261{ 262#if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED) 263 void (*decodefn)(struct sk_buff *, struct flowi *); 264 265 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 266 decodefn(skb, fl); 267#endif 268} 269 270#ifdef CONFIG_PROC_FS 271#include <linux/proc_fs.h> 272extern struct proc_dir_entry *proc_net_netfilter; 273#endif 274 275#else /* !CONFIG_NETFILTER */ 276#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 277#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 278static inline int nf_hook_thresh(int pf, unsigned int hook, 279 struct sk_buff *skb, 280 struct net_device *indev, 281 struct net_device *outdev, 282 int (*okfn)(struct sk_buff *), int thresh, 283 int cond) 284{ 285 return okfn(skb); 286} 287static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 288 struct net_device *indev, struct net_device *outdev, 289 int (*okfn)(struct sk_buff *)) 290{ 291 return 1; 292} 293struct flowi; 294static inline void 295nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 296#endif /*CONFIG_NETFILTER*/ 297 298#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 299extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 300extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 301extern void (*nf_ct_destroy)(struct nf_conntrack *); 302#else 303static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 304#endif 305 306#endif /*__KERNEL__*/ 307#endif /*__LINUX_NETFILTER_H*/ 308