1 #ifndef __LINUX_NETFILTER_H 2 #define __LINUX_NETFILTER_H 3 4 #include <linux/init.h> 5 #include <linux/skbuff.h> 6 #include <linux/net.h> 7 #include <linux/if.h> 8 #include <linux/in.h> 9 #include <linux/in6.h> 10 #include <linux/wait.h> 11 #include <linux/list.h> 12 #include <linux/static_key.h> 13 #include <uapi/linux/netfilter.h> 14 #ifdef CONFIG_NETFILTER 15 static inline int NF_DROP_GETERR(int verdict) 16 { 17 return -(verdict >> NF_VERDICT_QBITS); 18 } 19 20 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 21 const union nf_inet_addr *a2) 22 { 23 return a1->all[0] == a2->all[0] && 24 a1->all[1] == a2->all[1] && 25 a1->all[2] == a2->all[2] && 26 a1->all[3] == a2->all[3]; 27 } 28 29 static inline void nf_inet_addr_mask(const union nf_inet_addr *a1, 30 union nf_inet_addr *result, 31 const union nf_inet_addr *mask) 32 { 33 result->all[0] = a1->all[0] & mask->all[0]; 34 result->all[1] = a1->all[1] & mask->all[1]; 35 result->all[2] = a1->all[2] & mask->all[2]; 36 result->all[3] = a1->all[3] & mask->all[3]; 37 } 38 39 int netfilter_init(void); 40 41 /* Largest hook number + 1 */ 42 #define NF_MAX_HOOKS 8 43 44 struct sk_buff; 45 46 struct nf_hook_ops; 47 typedef unsigned int nf_hookfn(const struct nf_hook_ops *ops, 48 struct sk_buff *skb, 49 const struct net_device *in, 50 const struct net_device *out, 51 int (*okfn)(struct sk_buff *)); 52 53 struct nf_hook_ops { 54 struct list_head list; 55 56 /* User fills in from here down. */ 57 nf_hookfn *hook; 58 struct module *owner; 59 void *priv; 60 u_int8_t pf; 61 unsigned int hooknum; 62 /* Hooks are ordered in ascending priority. */ 63 int priority; 64 }; 65 66 struct nf_sockopt_ops { 67 struct list_head list; 68 69 u_int8_t pf; 70 71 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 72 int set_optmin; 73 int set_optmax; 74 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 75 #ifdef CONFIG_COMPAT 76 int (*compat_set)(struct sock *sk, int optval, 77 void __user *user, unsigned int len); 78 #endif 79 int get_optmin; 80 int get_optmax; 81 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 82 #ifdef CONFIG_COMPAT 83 int (*compat_get)(struct sock *sk, int optval, 84 void __user *user, int *len); 85 #endif 86 /* Use the module struct to lock set/get code in place */ 87 struct module *owner; 88 }; 89 90 /* Function to register/unregister hook points. */ 91 int nf_register_hook(struct nf_hook_ops *reg); 92 void nf_unregister_hook(struct nf_hook_ops *reg); 93 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 94 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 95 96 /* Functions to register get/setsockopt ranges (non-inclusive). You 97 need to check permissions yourself! */ 98 int nf_register_sockopt(struct nf_sockopt_ops *reg); 99 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 100 101 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 102 103 #ifdef HAVE_JUMP_LABEL 104 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 105 106 static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) 107 { 108 if (__builtin_constant_p(pf) && 109 __builtin_constant_p(hook)) 110 return static_key_false(&nf_hooks_needed[pf][hook]); 111 112 return !list_empty(&nf_hooks[pf][hook]); 113 } 114 #else 115 static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) 116 { 117 return !list_empty(&nf_hooks[pf][hook]); 118 } 119 #endif 120 121 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 122 struct net_device *indev, struct net_device *outdev, 123 int (*okfn)(struct sk_buff *), int thresh); 124 125 /** 126 * nf_hook_thresh - call a netfilter hook 127 * 128 * Returns 1 if the hook has allowed the packet to pass. The function 129 * okfn must be invoked by the caller in this case. Any other return 130 * value indicates the packet has been consumed by the hook. 131 */ 132 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 133 struct sk_buff *skb, 134 struct net_device *indev, 135 struct net_device *outdev, 136 int (*okfn)(struct sk_buff *), int thresh) 137 { 138 if (nf_hooks_active(pf, hook)) 139 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 140 return 1; 141 } 142 143 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 144 struct net_device *indev, struct net_device *outdev, 145 int (*okfn)(struct sk_buff *)) 146 { 147 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN); 148 } 149 150 /* Activate hook; either okfn or kfree_skb called, unless a hook 151 returns NF_STOLEN (in which case, it's up to the hook to deal with 152 the consequences). 153 154 Returns -ERRNO if packet dropped. Zero means queued, stolen or 155 accepted. 156 */ 157 158 /* RR: 159 > I don't want nf_hook to return anything because people might forget 160 > about async and trust the return value to mean "packet was ok". 161 162 AK: 163 Just document it clearly, then you can expect some sense from kernel 164 coders :) 165 */ 166 167 static inline int 168 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb, 169 struct net_device *in, struct net_device *out, 170 int (*okfn)(struct sk_buff *), int thresh) 171 { 172 int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh); 173 if (ret == 1) 174 ret = okfn(skb); 175 return ret; 176 } 177 178 static inline int 179 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb, 180 struct net_device *in, struct net_device *out, 181 int (*okfn)(struct sk_buff *), bool cond) 182 { 183 int ret; 184 185 if (!cond || 186 ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1)) 187 ret = okfn(skb); 188 return ret; 189 } 190 191 static inline int 192 NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb, 193 struct net_device *in, struct net_device *out, 194 int (*okfn)(struct sk_buff *)) 195 { 196 return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN); 197 } 198 199 /* Call setsockopt() */ 200 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 201 unsigned int len); 202 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 203 int *len); 204 #ifdef CONFIG_COMPAT 205 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 206 char __user *opt, unsigned int len); 207 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 208 char __user *opt, int *len); 209 #endif 210 211 /* Call this before modifying an existing packet: ensures it is 212 modifiable and linear to the point you care about (writable_len). 213 Returns true or false. */ 214 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 215 216 struct flowi; 217 struct nf_queue_entry; 218 219 struct nf_afinfo { 220 unsigned short family; 221 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 222 unsigned int dataoff, u_int8_t protocol); 223 __sum16 (*checksum_partial)(struct sk_buff *skb, 224 unsigned int hook, 225 unsigned int dataoff, 226 unsigned int len, 227 u_int8_t protocol); 228 int (*route)(struct net *net, struct dst_entry **dst, 229 struct flowi *fl, bool strict); 230 void (*saveroute)(const struct sk_buff *skb, 231 struct nf_queue_entry *entry); 232 int (*reroute)(struct sk_buff *skb, 233 const struct nf_queue_entry *entry); 234 int route_key_size; 235 }; 236 237 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO]; 238 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 239 { 240 return rcu_dereference(nf_afinfo[family]); 241 } 242 243 static inline __sum16 244 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 245 u_int8_t protocol, unsigned short family) 246 { 247 const struct nf_afinfo *afinfo; 248 __sum16 csum = 0; 249 250 rcu_read_lock(); 251 afinfo = nf_get_afinfo(family); 252 if (afinfo) 253 csum = afinfo->checksum(skb, hook, dataoff, protocol); 254 rcu_read_unlock(); 255 return csum; 256 } 257 258 static inline __sum16 259 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 260 unsigned int dataoff, unsigned int len, 261 u_int8_t protocol, unsigned short family) 262 { 263 const struct nf_afinfo *afinfo; 264 __sum16 csum = 0; 265 266 rcu_read_lock(); 267 afinfo = nf_get_afinfo(family); 268 if (afinfo) 269 csum = afinfo->checksum_partial(skb, hook, dataoff, len, 270 protocol); 271 rcu_read_unlock(); 272 return csum; 273 } 274 275 int nf_register_afinfo(const struct nf_afinfo *afinfo); 276 void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 277 278 #include <net/flow.h> 279 extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *); 280 281 static inline void 282 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 283 { 284 #ifdef CONFIG_NF_NAT_NEEDED 285 void (*decodefn)(struct sk_buff *, struct flowi *); 286 287 rcu_read_lock(); 288 decodefn = rcu_dereference(nf_nat_decode_session_hook); 289 if (decodefn) 290 decodefn(skb, fl); 291 rcu_read_unlock(); 292 #endif 293 } 294 295 #else /* !CONFIG_NETFILTER */ 296 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 297 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 298 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 299 struct sk_buff *skb, 300 struct net_device *indev, 301 struct net_device *outdev, 302 int (*okfn)(struct sk_buff *), int thresh) 303 { 304 return okfn(skb); 305 } 306 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 307 struct net_device *indev, struct net_device *outdev, 308 int (*okfn)(struct sk_buff *)) 309 { 310 return 1; 311 } 312 struct flowi; 313 static inline void 314 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 315 { 316 } 317 #endif /*CONFIG_NETFILTER*/ 318 319 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 320 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu; 321 void nf_ct_attach(struct sk_buff *, const struct sk_buff *); 322 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu; 323 324 struct nf_conn; 325 enum ip_conntrack_info; 326 struct nlattr; 327 328 struct nfq_ct_hook { 329 size_t (*build_size)(const struct nf_conn *ct); 330 int (*build)(struct sk_buff *skb, struct nf_conn *ct); 331 int (*parse)(const struct nlattr *attr, struct nf_conn *ct); 332 int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct, 333 u32 portid, u32 report); 334 void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct, 335 enum ip_conntrack_info ctinfo, s32 off); 336 }; 337 extern struct nfq_ct_hook __rcu *nfq_ct_hook; 338 #else 339 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 340 #endif 341 342 #endif /*__LINUX_NETFILTER_H*/ 343