include/net/netfilter/nf_tables.h

   1 #ifndef _NET_NF_TABLES_H
   2 #define _NET_NF_TABLES_H
   3
   4 #include <linux/list.h>
   5 #include <linux/netfilter.h>
   6 #include <linux/netfilter/nf_tables.h>
   7 #include <net/netlink.h>
   8
   9 #define NFT_JUMP_STACK_SIZE     16
  10
  11 struct nft_pktinfo {
  12         struct sk_buff                  *skb;
  13         const struct net_device         *in;
  14         const struct net_device         *out;
  15         u8                              hooknum;
  16         u8                              nhoff;
  17         u8                              thoff;
  18 };
  19
  20 struct nft_data {
  21         union {
  22                 u32                             data[4];
  23                 struct {
  24                         u32                     verdict;
  25                         struct nft_chain        *chain;
  26                 };
  27         };
  28 } __attribute__((aligned(__alignof__(u64))));
  29
  30 static inline int nft_data_cmp(const struct nft_data *d1,
  31                                const struct nft_data *d2,
  32                                unsigned int len)
  33 {
  34         return memcmp(d1->data, d2->data, len);
  35 }
  36
  37 static inline void nft_data_copy(struct nft_data *dst,
  38                                  const struct nft_data *src)
  39 {
  40         BUILD_BUG_ON(__alignof__(*dst) != __alignof__(u64));
  41         *(u64 *)&dst->data[0] = *(u64 *)&src->data[0];
  42         *(u64 *)&dst->data[2] = *(u64 *)&src->data[2];
  43 }
  44
  45 static inline void nft_data_debug(const struct nft_data *data)
  46 {
  47         pr_debug("data[0]=%x data[1]=%x data[2]=%x data[3]=%x\n",
  48                  data->data[0], data->data[1],
  49                  data->data[2], data->data[3]);
  50 }
  51
  52 /**
  53  *      struct nft_ctx - nf_tables rule/set context
  54  *
  55  *      @skb: netlink skb
  56  *      @nlh: netlink message header
  57  *      @afi: address family info
  58  *      @table: the table the chain is contained in
  59  *      @chain: the chain the rule is contained in
  60  */
  61 struct nft_ctx {
  62         const struct sk_buff            *skb;
  63         const struct nlmsghdr           *nlh;
  64         const struct nft_af_info        *afi;
  65         const struct nft_table          *table;
  66         const struct nft_chain          *chain;
  67 };
  68
  69 struct nft_data_desc {
  70         enum nft_data_types             type;
  71         unsigned int                    len;
  72 };
  73
  74 extern int nft_data_init(const struct nft_ctx *ctx, struct nft_data *data,
  75                          struct nft_data_desc *desc, const struct nlattr *nla);
  76 extern void nft_data_uninit(const struct nft_data *data,
  77                             enum nft_data_types type);
  78 extern int nft_data_dump(struct sk_buff *skb, int attr,
  79                          const struct nft_data *data,
  80                          enum nft_data_types type, unsigned int len);
  81
  82 static inline enum nft_data_types nft_dreg_to_type(enum nft_registers reg)
  83 {
  84         return reg == NFT_REG_VERDICT ? NFT_DATA_VERDICT : NFT_DATA_VALUE;
  85 }
  86
  87 static inline enum nft_registers nft_type_to_reg(enum nft_data_types type)
  88 {
  89         return type == NFT_DATA_VERDICT ? NFT_REG_VERDICT : NFT_REG_1;
  90 }
  91
  92 extern int nft_validate_input_register(enum nft_registers reg);
  93 extern int nft_validate_output_register(enum nft_registers reg);
  94 extern int nft_validate_data_load(const struct nft_ctx *ctx,
  95                                   enum nft_registers reg,
  96                                   const struct nft_data *data,
  97                                   enum nft_data_types type);
  98
  99 /**
 100  *      struct nft_set_elem - generic representation of set elements
 101  *
 102  *      @cookie: implementation specific element cookie
 103  *      @key: element key
 104  *      @data: element data (maps only)
 105  *      @flags: element flags (end of interval)
 106  *
 107  *      The cookie can be used to store a handle to the element for subsequent
 108  *      removal.
 109  */
 110 struct nft_set_elem {
 111         void                    *cookie;
 112         struct nft_data         key;
 113         struct nft_data         data;
 114         u32                     flags;
 115 };
 116
 117 struct nft_set;
 118 struct nft_set_iter {
 119         unsigned int    count;
 120         unsigned int    skip;
 121         int             err;
 122         int             (*fn)(const struct nft_ctx *ctx,
 123                               const struct nft_set *set,
 124                               const struct nft_set_iter *iter,
 125                               const struct nft_set_elem *elem);
 126 };
 127
 128 /**
 129  *      struct nft_set_ops - nf_tables set operations
 130  *
 131  *      @lookup: look up an element within the set
 132  *      @insert: insert new element into set
 133  *      @remove: remove element from set
 134  *      @walk: iterate over all set elemeennts
 135  *      @privsize: function to return size of set private data
 136  *      @init: initialize private data of new set instance
 137  *      @destroy: destroy private data of set instance
 138  *      @list: nf_tables_set_ops list node
 139  *      @owner: module reference
 140  *      @features: features supported by the implementation
 141  */
 142 struct nft_set_ops {
 143         bool                            (*lookup)(const struct nft_set *set,
 144                                                   const struct nft_data *key,
 145                                                   struct nft_data *data);
 146         int                             (*get)(const struct nft_set *set,
 147                                                struct nft_set_elem *elem);
 148         int                             (*insert)(const struct nft_set *set,
 149                                                   const struct nft_set_elem *elem);
 150         void                            (*remove)(const struct nft_set *set,
 151                                                   const struct nft_set_elem *elem);
 152         void                            (*walk)(const struct nft_ctx *ctx,
 153                                                 const struct nft_set *set,
 154                                                 struct nft_set_iter *iter);
 155
 156         unsigned int                    (*privsize)(const struct nlattr * const nla[]);
 157         int                             (*init)(const struct nft_set *set,
 158                                                 const struct nlattr * const nla[]);
 159         void                            (*destroy)(const struct nft_set *set);
 160
 161         struct list_head                list;
 162         struct module                   *owner;
 163         u32                             features;
 164 };
 165
 166 extern int nft_register_set(struct nft_set_ops *ops);
 167 extern void nft_unregister_set(struct nft_set_ops *ops);
 168
 169 /**
 170  *      struct nft_set - nf_tables set instance
 171  *
 172  *      @list: table set list node
 173  *      @bindings: list of set bindings
 174  *      @name: name of the set
 175  *      @ktype: key type (numeric type defined by userspace, not used in the kernel)
 176  *      @dtype: data type (verdict or numeric type defined by userspace)
 177  *      @ops: set ops
 178  *      @flags: set flags
 179  *      @klen: key length
 180  *      @dlen: data length
 181  *      @data: private set data
 182  */
 183 struct nft_set {
 184         struct list_head                list;
 185         struct list_head                bindings;
 186         char                            name[IFNAMSIZ];
 187         u32                             ktype;
 188         u32                             dtype;
 189         /* runtime data below here */
 190         const struct nft_set_ops        *ops ____cacheline_aligned;
 191         u16                             flags;
 192         u8                              klen;
 193         u8                              dlen;
 194         unsigned char                   data[]
 195                 __attribute__((aligned(__alignof__(u64))));
 196 };
 197
 198 static inline void *nft_set_priv(const struct nft_set *set)
 199 {
 200         return (void *)set->data;
 201 }
 202
 203 extern struct nft_set *nf_tables_set_lookup(const struct nft_table *table,
 204                                             const struct nlattr *nla);
 205
 206 /**
 207  *      struct nft_set_binding - nf_tables set binding
 208  *
 209  *      @list: set bindings list node
 210  *      @chain: chain containing the rule bound to the set
 211  *
 212  *      A set binding contains all information necessary for validation
 213  *      of new elements added to a bound set.
 214  */
 215 struct nft_set_binding {
 216         struct list_head                list;
 217         const struct nft_chain          *chain;
 218 };
 219
 220 extern int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
 221                               struct nft_set_binding *binding);
 222 extern void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
 223                                  struct nft_set_binding *binding);
 224
 225
 226 /**
 227  *      struct nft_expr_type - nf_tables expression type
 228  *
 229  *      @select_ops: function to select nft_expr_ops
 230  *      @ops: default ops, used when no select_ops functions is present
 231  *      @list: used internally
 232  *      @name: Identifier
 233  *      @owner: module reference
 234  *      @policy: netlink attribute policy
 235  *      @maxattr: highest netlink attribute number
 236  */
 237 struct nft_expr_type {
 238         const struct nft_expr_ops       *(*select_ops)(const struct nlattr * const tb[]);
 239         const struct nft_expr_ops       *ops;
 240         struct list_head                list;
 241         const char                      *name;
 242         struct module                   *owner;
 243         const struct nla_policy         *policy;
 244         unsigned int                    maxattr;
 245 };
 246
 247 /**
 248  *      struct nft_expr_ops - nf_tables expression operations
 249  *
 250  *      @eval: Expression evaluation function
 251  *      @size: full expression size, including private data size
 252  *      @init: initialization function
 253  *      @destroy: destruction function
 254  *      @dump: function to dump parameters
 255  *      @type: expression type
 256  */
 257 struct nft_expr;
 258 struct nft_expr_ops {
 259         void                            (*eval)(const struct nft_expr *expr,
 260                                                 struct nft_data data[NFT_REG_MAX + 1],
 261                                                 const struct nft_pktinfo *pkt);
 262         unsigned int                    size;
 263
 264         int                             (*init)(const struct nft_ctx *ctx,
 265                                                 const struct nft_expr *expr,
 266                                                 const struct nlattr * const tb[]);
 267         void                            (*destroy)(const struct nft_expr *expr);
 268         int                             (*dump)(struct sk_buff *skb,
 269                                                 const struct nft_expr *expr);
 270         const struct nft_data *         (*get_verdict)(const struct nft_expr *expr);
 271         const struct nft_expr_type      *type;
 272 };
 273
 274 #define NFT_EXPR_MAXATTR                16
 275 #define NFT_EXPR_SIZE(size)             (sizeof(struct nft_expr) + \
 276                                          ALIGN(size, __alignof__(struct nft_expr)))
 277
 278 /**
 279  *      struct nft_expr - nf_tables expression
 280  *
 281  *      @ops: expression ops
 282  *      @data: expression private data
 283  */
 284 struct nft_expr {
 285         const struct nft_expr_ops       *ops;
 286         unsigned char                   data[];
 287 };
 288
 289 static inline void *nft_expr_priv(const struct nft_expr *expr)
 290 {
 291         return (void *)expr->data;
 292 }
 293
 294 /**
 295  *      struct nft_rule - nf_tables rule
 296  *
 297  *      @list: used internally
 298  *      @rcu_head: used internally for rcu
 299  *      @handle: rule handle
 300  *      @dlen: length of expression data
 301  *      @data: expression data
 302  */
 303 struct nft_rule {
 304         struct list_head                list;
 305         struct rcu_head                 rcu_head;
 306         u64                             handle:48,
 307                                         dlen:16;
 308         unsigned char                   data[]
 309                 __attribute__((aligned(__alignof__(struct nft_expr))));
 310 };
 311
 312 static inline struct nft_expr *nft_expr_first(const struct nft_rule *rule)
 313 {
 314         return (struct nft_expr *)&rule->data[0];
 315 }
 316
 317 static inline struct nft_expr *nft_expr_next(const struct nft_expr *expr)
 318 {
 319         return ((void *)expr) + expr->ops->size;
 320 }
 321
 322 static inline struct nft_expr *nft_expr_last(const struct nft_rule *rule)
 323 {
 324         return (struct nft_expr *)&rule->data[rule->dlen];
 325 }
 326
 327 /*
 328  * The last pointer isn't really necessary, but the compiler isn't able to
 329  * determine that the result of nft_expr_last() is always the same since it
 330  * can't assume that the dlen value wasn't changed within calls in the loop.
 331  */
 332 #define nft_rule_for_each_expr(expr, last, rule) \
 333         for ((expr) = nft_expr_first(rule), (last) = nft_expr_last(rule); \
 334              (expr) != (last); \
 335              (expr) = nft_expr_next(expr))
 336
 337 enum nft_chain_flags {
 338         NFT_BASE_CHAIN                  = 0x1,
 339 };
 340
 341 /**
 342  *      struct nft_chain - nf_tables chain
 343  *
 344  *      @rules: list of rules in the chain
 345  *      @list: used internally
 346  *      @rcu_head: used internally
 347  *      @handle: chain handle
 348  *      @flags: bitmask of enum nft_chain_flags
 349  *      @use: number of jump references to this chain
 350  *      @level: length of longest path to this chain
 351  *      @name: name of the chain
 352  */
 353 struct nft_chain {
 354         struct list_head                rules;
 355         struct list_head                list;
 356         struct rcu_head                 rcu_head;
 357         u64                             handle;
 358         u8                              flags;
 359         u16                             use;
 360         u16                             level;
 361         char                            name[NFT_CHAIN_MAXNAMELEN];
 362 };
 363
 364 enum nft_chain_type {
 365         NFT_CHAIN_T_DEFAULT = 0,
 366         NFT_CHAIN_T_ROUTE,
 367         NFT_CHAIN_T_NAT,
 368         NFT_CHAIN_T_MAX
 369 };
 370
 371 /**
 372  *      struct nft_base_chain - nf_tables base chain
 373  *
 374  *      @ops: netfilter hook ops
 375  *      @type: chain type
 376  *      @chain: the chain
 377  */
 378 struct nft_base_chain {
 379         struct nf_hook_ops              ops;
 380         enum nft_chain_type             type;
 381         struct nft_chain                chain;
 382 };
 383
 384 static inline struct nft_base_chain *nft_base_chain(const struct nft_chain *chain)
 385 {
 386         return container_of(chain, struct nft_base_chain, chain);
 387 }
 388
 389 extern unsigned int nft_do_chain(const struct nf_hook_ops *ops,
 390                                  struct sk_buff *skb,
 391                                  const struct net_device *in,
 392                                  const struct net_device *out,
 393                                  int (*okfn)(struct sk_buff *));
 394
 395 /**
 396  *      struct nft_table - nf_tables table
 397  *
 398  *      @list: used internally
 399  *      @chains: chains in the table
 400  *      @sets: sets in the table
 401  *      @hgenerator: handle generator state
 402  *      @use: number of chain references to this table
 403  *      @flags: table flag (see enum nft_table_flags)
 404  *      @name: name of the table
 405  */
 406 struct nft_table {
 407         struct list_head                list;
 408         struct list_head                chains;
 409         struct list_head                sets;
 410         u64                             hgenerator;
 411         u32                             use;
 412         u16                             flags;
 413         char                            name[];
 414 };
 415
 416 /**
 417  *      struct nft_af_info - nf_tables address family info
 418  *
 419  *      @list: used internally
 420  *      @family: address family
 421  *      @nhooks: number of hooks in this family
 422  *      @owner: module owner
 423  *      @tables: used internally
 424  *      @hooks: hookfn overrides for packet validation
 425  */
 426 struct nft_af_info {
 427         struct list_head                list;
 428         int                             family;
 429         unsigned int                    nhooks;
 430         struct module                   *owner;
 431         struct list_head                tables;
 432         nf_hookfn                       *hooks[NF_MAX_HOOKS];
 433 };
 434
 435 extern int nft_register_afinfo(struct nft_af_info *);
 436 extern void nft_unregister_afinfo(struct nft_af_info *);
 437
 438 struct nf_chain_type {
 439         unsigned int            hook_mask;
 440         const char              *name;
 441         enum nft_chain_type     type;
 442         nf_hookfn               *fn[NF_MAX_HOOKS];
 443         struct module           *me;
 444         int                     family;
 445 };
 446
 447 extern int nft_register_chain_type(struct nf_chain_type *);
 448 extern void nft_unregister_chain_type(struct nf_chain_type *);
 449
 450 extern int nft_register_expr(struct nft_expr_type *);
 451 extern void nft_unregister_expr(struct nft_expr_type *);
 452
 453 #define MODULE_ALIAS_NFT_FAMILY(family) \
 454         MODULE_ALIAS("nft-afinfo-" __stringify(family))
 455
 456 #define MODULE_ALIAS_NFT_CHAIN(family, name) \
 457         MODULE_ALIAS("nft-chain-" __stringify(family) "-" name)
 458
 459 #define MODULE_ALIAS_NFT_EXPR(name) \
 460         MODULE_ALIAS("nft-expr-" name)
 461
 462 #define MODULE_ALIAS_NFT_SET() \
 463         MODULE_ALIAS("nft-set")
 464
 465 #endif /* _NET_NF_TABLES_H */