netfilter.h revision b8beedd25d3913d45b8330a08ab88fdf90eb54b8
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/in.h> 11#include <linux/in6.h> 12#include <linux/wait.h> 13#include <linux/list.h> 14#endif 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 53union nf_inet_addr { 54 __u32 all[4]; 55 __be32 ip; 56 __be32 ip6[4]; 57 struct in_addr in; 58 struct in6_addr in6; 59}; 60 61#ifdef __KERNEL__ 62#ifdef CONFIG_NETFILTER 63 64static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 65 const union nf_inet_addr *a2) 66{ 67 return a1->all[0] == a2->all[0] && 68 a1->all[1] == a2->all[1] && 69 a1->all[2] == a2->all[2] && 70 a1->all[3] == a2->all[3]; 71} 72 73extern void netfilter_init(void); 74 75/* Largest hook number + 1 */ 76#define NF_MAX_HOOKS 8 77 78struct sk_buff; 79struct net_device; 80 81typedef unsigned int nf_hookfn(unsigned int hooknum, 82 struct sk_buff *skb, 83 const struct net_device *in, 84 const struct net_device *out, 85 int (*okfn)(struct sk_buff *)); 86 87struct nf_hook_ops 88{ 89 struct list_head list; 90 91 /* User fills in from here down. */ 92 nf_hookfn *hook; 93 struct module *owner; 94 int pf; 95 int hooknum; 96 /* Hooks are ordered in ascending priority. */ 97 int priority; 98}; 99 100struct nf_sockopt_ops 101{ 102 struct list_head list; 103 104 int pf; 105 106 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 107 int set_optmin; 108 int set_optmax; 109 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 110 int (*compat_set)(struct sock *sk, int optval, 111 void __user *user, unsigned int len); 112 113 int get_optmin; 114 int get_optmax; 115 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 116 int (*compat_get)(struct sock *sk, int optval, 117 void __user *user, int *len); 118 119 /* Use the module struct to lock set/get code in place */ 120 struct module *owner; 121}; 122 123/* Function to register/unregister hook points. */ 124int nf_register_hook(struct nf_hook_ops *reg); 125void nf_unregister_hook(struct nf_hook_ops *reg); 126int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 127void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 128 129/* Functions to register get/setsockopt ranges (non-inclusive). You 130 need to check permissions yourself! */ 131int nf_register_sockopt(struct nf_sockopt_ops *reg); 132void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 133 134#ifdef CONFIG_SYSCTL 135/* Sysctl registration */ 136extern struct ctl_path nf_net_netfilter_sysctl_path[]; 137extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; 138#endif /* CONFIG_SYSCTL */ 139 140extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 141 142int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb, 143 struct net_device *indev, struct net_device *outdev, 144 int (*okfn)(struct sk_buff *), int thresh); 145 146/** 147 * nf_hook_thresh - call a netfilter hook 148 * 149 * Returns 1 if the hook has allowed the packet to pass. The function 150 * okfn must be invoked by the caller in this case. Any other return 151 * value indicates the packet has been consumed by the hook. 152 */ 153static inline int nf_hook_thresh(int pf, unsigned int hook, 154 struct sk_buff *skb, 155 struct net_device *indev, 156 struct net_device *outdev, 157 int (*okfn)(struct sk_buff *), int thresh, 158 int cond) 159{ 160 if (!cond) 161 return 1; 162#ifndef CONFIG_NETFILTER_DEBUG 163 if (list_empty(&nf_hooks[pf][hook])) 164 return 1; 165#endif 166 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 167} 168 169static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 170 struct net_device *indev, struct net_device *outdev, 171 int (*okfn)(struct sk_buff *)) 172{ 173 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1); 174} 175 176/* Activate hook; either okfn or kfree_skb called, unless a hook 177 returns NF_STOLEN (in which case, it's up to the hook to deal with 178 the consequences). 179 180 Returns -ERRNO if packet dropped. Zero means queued, stolen or 181 accepted. 182*/ 183 184/* RR: 185 > I don't want nf_hook to return anything because people might forget 186 > about async and trust the return value to mean "packet was ok". 187 188 AK: 189 Just document it clearly, then you can expect some sense from kernel 190 coders :) 191*/ 192 193/* This is gross, but inline doesn't cut it for avoiding the function 194 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 195 196/* HX: It's slightly less gross now. */ 197 198#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 199({int __ret; \ 200if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\ 201 __ret = (okfn)(skb); \ 202__ret;}) 203 204#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 205({int __ret; \ 206if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 207 __ret = (okfn)(skb); \ 208__ret;}) 209 210#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 211 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 212 213/* Call setsockopt() */ 214int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 215 int len); 216int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 217 int *len); 218 219int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 220 char __user *opt, int len); 221int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 222 char __user *opt, int *len); 223 224/* Call this before modifying an existing packet: ensures it is 225 modifiable and linear to the point you care about (writable_len). 226 Returns true or false. */ 227extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 228 229struct flowi; 230struct nf_queue_entry; 231 232struct nf_afinfo { 233 unsigned short family; 234 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 235 unsigned int dataoff, u_int8_t protocol); 236 int (*route)(struct dst_entry **dst, struct flowi *fl); 237 void (*saveroute)(const struct sk_buff *skb, 238 struct nf_queue_entry *entry); 239 int (*reroute)(struct sk_buff *skb, 240 const struct nf_queue_entry *entry); 241 int route_key_size; 242}; 243 244extern const struct nf_afinfo *nf_afinfo[NPROTO]; 245static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 246{ 247 return rcu_dereference(nf_afinfo[family]); 248} 249 250static inline __sum16 251nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 252 u_int8_t protocol, unsigned short family) 253{ 254 const struct nf_afinfo *afinfo; 255 __sum16 csum = 0; 256 257 rcu_read_lock(); 258 afinfo = nf_get_afinfo(family); 259 if (afinfo) 260 csum = afinfo->checksum(skb, hook, dataoff, protocol); 261 rcu_read_unlock(); 262 return csum; 263} 264 265extern int nf_register_afinfo(const struct nf_afinfo *afinfo); 266extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 267 268#include <net/flow.h> 269extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 270 271static inline void 272nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 273{ 274#ifdef CONFIG_NF_NAT_NEEDED 275 void (*decodefn)(struct sk_buff *, struct flowi *); 276 277 if (family == AF_INET) { 278 rcu_read_lock(); 279 decodefn = rcu_dereference(ip_nat_decode_session); 280 if (decodefn) 281 decodefn(skb, fl); 282 rcu_read_unlock(); 283 } 284#endif 285} 286 287#ifdef CONFIG_PROC_FS 288#include <linux/proc_fs.h> 289extern struct proc_dir_entry *proc_net_netfilter; 290#endif 291 292#else /* !CONFIG_NETFILTER */ 293#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 294#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 295static inline int nf_hook_thresh(int pf, unsigned int hook, 296 struct sk_buff *skb, 297 struct net_device *indev, 298 struct net_device *outdev, 299 int (*okfn)(struct sk_buff *), int thresh, 300 int cond) 301{ 302 return okfn(skb); 303} 304static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 305 struct net_device *indev, struct net_device *outdev, 306 int (*okfn)(struct sk_buff *)) 307{ 308 return 1; 309} 310struct flowi; 311static inline void 312nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 313#endif /*CONFIG_NETFILTER*/ 314 315#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 316extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 317extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 318extern void (*nf_ct_destroy)(struct nf_conntrack *); 319#else 320static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 321#endif 322 323#endif /*__KERNEL__*/ 324#endif /*__LINUX_NETFILTER_H*/ 325