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/x_tables.h>
   7 #include <linux/netfilter/nf_tables.h>
   8 #include <net/netlink.h>
   9
  10 #define NFT_JUMP_STACK_SIZE     16
  11
  12 struct nft_pktinfo {
  13         struct sk_buff                  *skb;
  14         const struct net_device         *in;
  15         const struct net_device         *out;
  16         const struct nf_hook_ops        *ops;
  17         u8                              nhoff;
  18         u8                              thoff;
  19         u8                              tprot;
  20         /* for x_tables compatibility */
  21         struct xt_action_param          xt;
  22 };
  23
  24 static inline void nft_set_pktinfo(struct nft_pktinfo *pkt,
  25                                    const struct nf_hook_ops *ops,
  26                                    struct sk_buff *skb,
  27                                    const struct net_device *in,
  28                                    const struct net_device *out)
  29 {
  30         pkt->skb = skb;
  31         pkt->in = pkt->xt.in = in;
  32         pkt->out = pkt->xt.out = out;
  33         pkt->ops = ops;
  34         pkt->xt.hooknum = ops->hooknum;
  35         pkt->xt.family = ops->pf;
  36 }
  37
  38 struct nft_data {
  39         union {
  40                 u32                             data[4];
  41                 struct {
  42                         u32                     verdict;
  43                         struct nft_chain        *chain;
  44                 };
  45         };
  46 } __attribute__((aligned(__alignof__(u64))));
  47
  48 static inline int nft_data_cmp(const struct nft_data *d1,
  49                                const struct nft_data *d2,
  50                                unsigned int len)
  51 {
  52         return memcmp(d1->data, d2->data, len);
  53 }
  54
  55 static inline void nft_data_copy(struct nft_data *dst,
  56                                  const struct nft_data *src)
  57 {
  58         BUILD_BUG_ON(__alignof__(*dst) != __alignof__(u64));
  59         *(u64 *)&dst->data[0] = *(u64 *)&src->data[0];
  60         *(u64 *)&dst->data[2] = *(u64 *)&src->data[2];
  61 }
  62
  63 static inline void nft_data_debug(const struct nft_data *data)
  64 {
  65         pr_debug("data[0]=%x data[1]=%x data[2]=%x data[3]=%x\n",
  66                  data->data[0], data->data[1],
  67                  data->data[2], data->data[3]);
  68 }
  69
  70 /**
  71  *      struct nft_ctx - nf_tables rule/set context
  72  *
  73  *      @net: net namespace
  74  *      @skb: netlink skb
  75  *      @nlh: netlink message header
  76  *      @afi: address family info
  77  *      @table: the table the chain is contained in
  78  *      @chain: the chain the rule is contained in
  79  *      @nla: netlink attributes
  80  */
  81 struct nft_ctx {
  82         struct net                      *net;
  83         const struct sk_buff            *skb;
  84         const struct nlmsghdr           *nlh;
  85         const struct nft_af_info        *afi;
  86         const struct nft_table          *table;
  87         const struct nft_chain          *chain;
  88         const struct nlattr * const     *nla;
  89 };
  90
  91 struct nft_data_desc {
  92         enum nft_data_types             type;
  93         unsigned int                    len;
  94 };
  95
  96 int nft_data_init(const struct nft_ctx *ctx, struct nft_data *data,
  97                   struct nft_data_desc *desc, const struct nlattr *nla);
  98 void nft_data_uninit(const struct nft_data *data, enum nft_data_types type);
  99 int nft_data_dump(struct sk_buff *skb, int attr, const struct nft_data *data,
 100                   enum nft_data_types type, unsigned int len);
 101
 102 static inline enum nft_data_types nft_dreg_to_type(enum nft_registers reg)
 103 {
 104         return reg == NFT_REG_VERDICT ? NFT_DATA_VERDICT : NFT_DATA_VALUE;
 105 }
 106
 107 static inline enum nft_registers nft_type_to_reg(enum nft_data_types type)
 108 {
 109         return type == NFT_DATA_VERDICT ? NFT_REG_VERDICT : NFT_REG_1;
 110 }
 111
 112 int nft_validate_input_register(enum nft_registers reg);
 113 int nft_validate_output_register(enum nft_registers reg);
 114 int nft_validate_data_load(const struct nft_ctx *ctx, enum nft_registers reg,
 115                            const struct nft_data *data,
 116                            enum nft_data_types type);
 117
 118 /**
 119  *      struct nft_set_elem - generic representation of set elements
 120  *
 121  *      @cookie: implementation specific element cookie
 122  *      @key: element key
 123  *      @data: element data (maps only)
 124  *      @flags: element flags (end of interval)
 125  *
 126  *      The cookie can be used to store a handle to the element for subsequent
 127  *      removal.
 128  */
 129 struct nft_set_elem {
 130         void                    *cookie;
 131         struct nft_data         key;
 132         struct nft_data         data;
 133         u32                     flags;
 134 };
 135
 136 struct nft_set;
 137 struct nft_set_iter {
 138         unsigned int    count;
 139         unsigned int    skip;
 140         int             err;
 141         int             (*fn)(const struct nft_ctx *ctx,
 142                               const struct nft_set *set,
 143                               const struct nft_set_iter *iter,
 144                               const struct nft_set_elem *elem);
 145 };
 146
 147 /**
 148  *      struct nft_set_ops - nf_tables set operations
 149  *
 150  *      @lookup: look up an element within the set
 151  *      @insert: insert new element into set
 152  *      @remove: remove element from set
 153  *      @walk: iterate over all set elemeennts
 154  *      @privsize: function to return size of set private data
 155  *      @init: initialize private data of new set instance
 156  *      @destroy: destroy private data of set instance
 157  *      @list: nf_tables_set_ops list node
 158  *      @owner: module reference
 159  *      @features: features supported by the implementation
 160  */
 161 struct nft_set_ops {
 162         bool                            (*lookup)(const struct nft_set *set,
 163                                                   const struct nft_data *key,
 164                                                   struct nft_data *data);
 165         int                             (*get)(const struct nft_set *set,
 166                                                struct nft_set_elem *elem);
 167         int                             (*insert)(const struct nft_set *set,
 168                                                   const struct nft_set_elem *elem);
 169         void                            (*remove)(const struct nft_set *set,
 170                                                   const struct nft_set_elem *elem);
 171         void                            (*walk)(const struct nft_ctx *ctx,
 172                                                 const struct nft_set *set,
 173                                                 struct nft_set_iter *iter);
 174
 175         unsigned int                    (*privsize)(const struct nlattr * const nla[]);
 176         int                             (*init)(const struct nft_set *set,
 177                                                 const struct nlattr * const nla[]);
 178         void                            (*destroy)(const struct nft_set *set);
 179
 180         struct list_head                list;
 181         struct module                   *owner;
 182         u32                             features;
 183 };
 184
 185 int nft_register_set(struct nft_set_ops *ops);
 186 void nft_unregister_set(struct nft_set_ops *ops);
 187
 188 /**
 189  *      struct nft_set - nf_tables set instance
 190  *
 191  *      @list: table set list node
 192  *      @bindings: list of set bindings
 193  *      @name: name of the set
 194  *      @ktype: key type (numeric type defined by userspace, not used in the kernel)
 195  *      @dtype: data type (verdict or numeric type defined by userspace)
 196  *      @ops: set ops
 197  *      @flags: set flags
 198  *      @klen: key length
 199  *      @dlen: data length
 200  *      @data: private set data
 201  */
 202 struct nft_set {
 203         struct list_head                list;
 204         struct list_head                bindings;
 205         char                            name[IFNAMSIZ];
 206         u32                             ktype;
 207         u32                             dtype;
 208         /* runtime data below here */
 209         const struct nft_set_ops        *ops ____cacheline_aligned;
 210         u16                             flags;
 211         u8                              klen;
 212         u8                              dlen;
 213         unsigned char                   data[]
 214                 __attribute__((aligned(__alignof__(u64))));
 215 };
 216
 217 static inline void *nft_set_priv(const struct nft_set *set)
 218 {
 219         return (void *)set->data;
 220 }
 221
 222 struct nft_set *nf_tables_set_lookup(const struct nft_table *table,
 223                                      const struct nlattr *nla);
 224
 225 /**
 226  *      struct nft_set_binding - nf_tables set binding
 227  *
 228  *      @list: set bindings list node
 229  *      @chain: chain containing the rule bound to the set
 230  *
 231  *      A set binding contains all information necessary for validation
 232  *      of new elements added to a bound set.
 233  */
 234 struct nft_set_binding {
 235         struct list_head                list;
 236         const struct nft_chain          *chain;
 237 };
 238
 239 int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
 240                        struct nft_set_binding *binding);
 241 void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
 242                           struct nft_set_binding *binding);
 243
 244
 245 /**
 246  *      struct nft_expr_type - nf_tables expression type
 247  *
 248  *      @select_ops: function to select nft_expr_ops
 249  *      @ops: default ops, used when no select_ops functions is present
 250  *      @list: used internally
 251  *      @name: Identifier
 252  *      @owner: module reference
 253  *      @policy: netlink attribute policy
 254  *      @maxattr: highest netlink attribute number
 255  */
 256 struct nft_expr_type {
 257         const struct nft_expr_ops       *(*select_ops)(const struct nft_ctx *,
 258                                                        const struct nlattr * const tb[]);
 259         const struct nft_expr_ops       *ops;
 260         struct list_head                list;
 261         const char                      *name;
 262         struct module                   *owner;
 263         const struct nla_policy         *policy;
 264         unsigned int                    maxattr;
 265 };
 266
 267 /**
 268  *      struct nft_expr_ops - nf_tables expression operations
 269  *
 270  *      @eval: Expression evaluation function
 271  *      @size: full expression size, including private data size
 272  *      @init: initialization function
 273  *      @destroy: destruction function
 274  *      @dump: function to dump parameters
 275  *      @type: expression type
 276  *      @validate: validate expression, called during loop detection
 277  *      @data: extra data to attach to this expression operation
 278  */
 279 struct nft_expr;
 280 struct nft_expr_ops {
 281         void                            (*eval)(const struct nft_expr *expr,
 282                                                 struct nft_data data[NFT_REG_MAX + 1],
 283                                                 const struct nft_pktinfo *pkt);
 284         unsigned int                    size;
 285
 286         int                             (*init)(const struct nft_ctx *ctx,
 287                                                 const struct nft_expr *expr,
 288                                                 const struct nlattr * const tb[]);
 289         void                            (*destroy)(const struct nft_expr *expr);
 290         int                             (*dump)(struct sk_buff *skb,
 291                                                 const struct nft_expr *expr);
 292         int                             (*validate)(const struct nft_ctx *ctx,
 293                                                     const struct nft_expr *expr,
 294                                                     const struct nft_data **data);
 295         const struct nft_expr_type      *type;
 296         void                            *data;
 297 };
 298
 299 #define NFT_EXPR_MAXATTR                16
 300 #define NFT_EXPR_SIZE(size)             (sizeof(struct nft_expr) + \
 301                                          ALIGN(size, __alignof__(struct nft_expr)))
 302
 303 /**
 304  *      struct nft_expr - nf_tables expression
 305  *
 306  *      @ops: expression ops
 307  *      @data: expression private data
 308  */
 309 struct nft_expr {
 310         const struct nft_expr_ops       *ops;
 311         unsigned char                   data[];
 312 };
 313
 314 static inline void *nft_expr_priv(const struct nft_expr *expr)
 315 {
 316         return (void *)expr->data;
 317 }
 318
 319 /**
 320  *      struct nft_rule - nf_tables rule
 321  *
 322  *      @list: used internally
 323  *      @rcu_head: used internally for rcu
 324  *      @handle: rule handle
 325  *      @genmask: generation mask
 326  *      @dlen: length of expression data
 327  *      @data: expression data
 328  */
 329 struct nft_rule {
 330         struct list_head                list;
 331         struct rcu_head                 rcu_head;
 332         u64                             handle:46,
 333                                         genmask:2,
 334                                         dlen:16;
 335         unsigned char                   data[]
 336                 __attribute__((aligned(__alignof__(struct nft_expr))));
 337 };
 338
 339 /**
 340  *      struct nft_rule_trans - nf_tables rule update in transaction
 341  *
 342  *      @list: used internally
 343  *      @rule: rule that needs to be updated
 344  *      @chain: chain that this rule belongs to
 345  *      @table: table for which this chain applies
 346  *      @nlh: netlink header of the message that contain this update
 347  *      @family: family expressesed as AF_*
 348  */
 349 struct nft_rule_trans {
 350         struct list_head                list;
 351         struct nft_rule                 *rule;
 352         const struct nft_chain          *chain;
 353         const struct nft_table          *table;
 354         const struct nlmsghdr           *nlh;
 355         u8                              family;
 356 };
 357
 358 static inline struct nft_expr *nft_expr_first(const struct nft_rule *rule)
 359 {
 360         return (struct nft_expr *)&rule->data[0];
 361 }
 362
 363 static inline struct nft_expr *nft_expr_next(const struct nft_expr *expr)
 364 {
 365         return ((void *)expr) + expr->ops->size;
 366 }
 367
 368 static inline struct nft_expr *nft_expr_last(const struct nft_rule *rule)
 369 {
 370         return (struct nft_expr *)&rule->data[rule->dlen];
 371 }
 372
 373 /*
 374  * The last pointer isn't really necessary, but the compiler isn't able to
 375  * determine that the result of nft_expr_last() is always the same since it
 376  * can't assume that the dlen value wasn't changed within calls in the loop.
 377  */
 378 #define nft_rule_for_each_expr(expr, last, rule) \
 379         for ((expr) = nft_expr_first(rule), (last) = nft_expr_last(rule); \
 380              (expr) != (last); \
 381              (expr) = nft_expr_next(expr))
 382
 383 enum nft_chain_flags {
 384         NFT_BASE_CHAIN                  = 0x1,
 385 };
 386
 387 /**
 388  *      struct nft_chain - nf_tables chain
 389  *
 390  *      @rules: list of rules in the chain
 391  *      @list: used internally
 392  *      @rcu_head: used internally
 393  *      @net: net namespace that this chain belongs to
 394  *      @table: table that this chain belongs to
 395  *      @handle: chain handle
 396  *      @flags: bitmask of enum nft_chain_flags
 397  *      @use: number of jump references to this chain
 398  *      @level: length of longest path to this chain
 399  *      @name: name of the chain
 400  */
 401 struct nft_chain {
 402         struct list_head                rules;
 403         struct list_head                list;
 404         struct rcu_head                 rcu_head;
 405         struct net                      *net;
 406         struct nft_table                *table;
 407         u64                             handle;
 408         u8                              flags;
 409         u16                             use;
 410         u16                             level;
 411         char                            name[NFT_CHAIN_MAXNAMELEN];
 412 };
 413
 414 enum nft_chain_type {
 415         NFT_CHAIN_T_DEFAULT = 0,
 416         NFT_CHAIN_T_ROUTE,
 417         NFT_CHAIN_T_NAT,
 418         NFT_CHAIN_T_MAX
 419 };
 420
 421 struct nft_stats {
 422         u64 bytes;
 423         u64 pkts;
 424 };
 425
 426 #define NFT_HOOK_OPS_MAX                2
 427
 428 /**
 429  *      struct nft_base_chain - nf_tables base chain
 430  *
 431  *      @ops: netfilter hook ops
 432  *      @type: chain type
 433  *      @policy: default policy
 434  *      @stats: per-cpu chain stats
 435  *      @chain: the chain
 436  */
 437 struct nft_base_chain {
 438         struct nf_hook_ops              ops[NFT_HOOK_OPS_MAX];
 439         struct nf_chain_type            *type;
 440         u8                              policy;
 441         struct nft_stats __percpu       *stats;
 442         struct nft_chain                chain;
 443 };
 444
 445 static inline struct nft_base_chain *nft_base_chain(const struct nft_chain *chain)
 446 {
 447         return container_of(chain, struct nft_base_chain, chain);
 448 }
 449
 450 unsigned int nft_do_chain_pktinfo(struct nft_pktinfo *pkt,
 451                                   const struct nf_hook_ops *ops);
 452
 453 /**
 454  *      struct nft_table - nf_tables table
 455  *
 456  *      @list: used internally
 457  *      @chains: chains in the table
 458  *      @sets: sets in the table
 459  *      @hgenerator: handle generator state
 460  *      @use: number of chain references to this table
 461  *      @flags: table flag (see enum nft_table_flags)
 462  *      @name: name of the table
 463  */
 464 struct nft_table {
 465         struct list_head                list;
 466         struct list_head                chains;
 467         struct list_head                sets;
 468         u64                             hgenerator;
 469         u32                             use;
 470         u16                             flags;
 471         char                            name[];
 472 };
 473
 474 /**
 475  *      struct nft_af_info - nf_tables address family info
 476  *
 477  *      @list: used internally
 478  *      @family: address family
 479  *      @nhooks: number of hooks in this family
 480  *      @owner: module owner
 481  *      @tables: used internally
 482  *      @nops: number of hook ops in this family
 483  *      @hook_ops_init: initialization function for chain hook ops
 484  *      @hooks: hookfn overrides for packet validation
 485  */
 486 struct nft_af_info {
 487         struct list_head                list;
 488         int                             family;
 489         unsigned int                    nhooks;
 490         struct module                   *owner;
 491         struct list_head                tables;
 492         unsigned int                    nops;
 493         void                            (*hook_ops_init)(struct nf_hook_ops *,
 494                                                          unsigned int);
 495         nf_hookfn                       *hooks[NF_MAX_HOOKS];
 496 };
 497
 498 int nft_register_afinfo(struct net *, struct nft_af_info *);
 499 void nft_unregister_afinfo(struct nft_af_info *);
 500
 501 struct nf_chain_type {
 502         unsigned int            hook_mask;
 503         const char              *name;
 504         enum nft_chain_type     type;
 505         nf_hookfn               *fn[NF_MAX_HOOKS];
 506         struct module           *me;
 507         int                     family;
 508 };
 509
 510 int nft_register_chain_type(struct nf_chain_type *);
 511 void nft_unregister_chain_type(struct nf_chain_type *);
 512
 513 int nft_register_expr(struct nft_expr_type *);
 514 void nft_unregister_expr(struct nft_expr_type *);
 515
 516 #define MODULE_ALIAS_NFT_FAMILY(family) \
 517         MODULE_ALIAS("nft-afinfo-" __stringify(family))
 518
 519 #define MODULE_ALIAS_NFT_CHAIN(family, name) \
 520         MODULE_ALIAS("nft-chain-" __stringify(family) "-" name)
 521
 522 #define MODULE_ALIAS_NFT_EXPR(name) \
 523         MODULE_ALIAS("nft-expr-" name)
 524
 525 #define MODULE_ALIAS_NFT_SET() \
 526         MODULE_ALIAS("nft-set")
 527
 528 #endif /* _NET_NF_TABLES_H */