lib/yang.h

   1 /*
   2  * Copyright (C) 2018  NetDEF, Inc.
   3  *                     Renato Westphal
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the Free
   7  * Software Foundation; either version 2 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; see the file COPYING; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #ifndef _FRR_YANG_H_
  21 #define _FRR_YANG_H_
  22
  23 #include "memory.h"
  24
  25 #include <libyang/libyang.h>
  26 #ifdef HAVE_SYSREPO
  27 #include <sysrepo.h>
  28 #endif
  29
  30 #include "yang_wrappers.h"
  31
  32 DECLARE_MTYPE(YANG_MODULE)
  33 DECLARE_MTYPE(YANG_DATA)
  34
  35 /* Maximum XPath length. */
  36 #define XPATH_MAXLEN 256
  37
  38 /* Maximum list key length. */
  39 #define LIST_MAXKEYS 8
  40
  41 /* Maximum list key length. */
  42 #define LIST_MAXKEYLEN 128
  43
  44 /* Maximum string length of an YANG value. */
  45 #define YANG_VALUE_MAXLEN 1024
  46
  47 struct yang_module_embed {
  48         struct yang_module_embed *next;
  49         const char *mod_name, *mod_rev;
  50         const char *data;
  51         LYS_INFORMAT format;
  52 };
  53
  54 struct yang_module {
  55         RB_ENTRY(yang_module) entry;
  56         const char *name;
  57         const struct lys_module *info;
  58 #ifdef HAVE_CONFD
  59         int confd_hash;
  60 #endif
  61 #ifdef HAVE_SYSREPO
  62         sr_subscription_ctx_t *sr_subscription;
  63 #endif
  64 };
  65 RB_HEAD(yang_modules, yang_module);
  66 RB_PROTOTYPE(yang_modules, yang_module, entry, yang_module_compare);
  67
  68 struct yang_data {
  69         /* XPath identifier of the data element. */
  70         char xpath[XPATH_MAXLEN];
  71
  72         /* Value encoded as a raw string. */
  73         char *value;
  74 };
  75
  76 struct yang_list_keys {
  77         /* Number os keys (max: LIST_MAXKEYS). */
  78         uint8_t num;
  79
  80         /* Value encoded as a raw string. */
  81         char key[LIST_MAXKEYS][LIST_MAXKEYLEN];
  82 };
  83
  84 enum yang_path_type {
  85         YANG_PATH_SCHEMA = 0,
  86         YANG_PATH_DATA,
  87 };
  88
  89 enum yang_iter_flags {
  90         /* Filter non-presence containers. */
  91         YANG_ITER_FILTER_NPCONTAINERS = (1<<0),
  92
  93         /* Filter list keys (leafs). */
  94         YANG_ITER_FILTER_LIST_KEYS = (1<<1),
  95
  96         /* Filter RPC input/output nodes. */
  97         YANG_ITER_FILTER_INPUT_OUTPUT = (1<<2),
  98
  99         /* Filter implicitely created nodes. */
 100         YANG_ITER_FILTER_IMPLICIT = (1<<3),
 101 };
 102
 103 /* Callback used by the yang_snodes_iterate_*() family of functions. */
 104 typedef int (*yang_iterate_cb)(const struct lys_node *snode, void *arg);
 105
 106 /* Return values of the 'yang_iterate_cb' callback. */
 107 #define YANG_ITER_CONTINUE 0
 108 #define YANG_ITER_STOP -1
 109
 110 /* Global libyang context for native FRR models. */
 111 extern struct ly_ctx *ly_native_ctx;
 112
 113 /* Tree of all loaded YANG modules. */
 114 extern struct yang_modules yang_modules;
 115
 116 /*
 117  * Create a new YANG module and load it using libyang. If the YANG module is not
 118  * found in the YANG_MODELS_PATH directory, the program will exit with an error.
 119  * Once loaded, a YANG module can't be unloaded anymore.
 120  *
 121  * module_name
 122  *    Name of the YANG module.
 123  *
 124  * Returns:
 125  *    Pointer to newly created YANG module.
 126  */
 127 extern struct yang_module *yang_module_load(const char *module_name);
 128
 129 /*
 130  * Load all FRR native YANG models.
 131  */
 132 extern void yang_module_load_all(void);
 133
 134 /*
 135  * Find a YANG module by its name.
 136  *
 137  * module_name
 138  *    Name of the YANG module.
 139  *
 140  * Returns:
 141  *    Pointer to YANG module if found, NULL otherwise.
 142  */
 143 extern struct yang_module *yang_module_find(const char *module_name);
 144
 145 /*
 146  * Register a YANG module embedded in the binary file.  Should be called
 147  * from a constructor function.
 148  *
 149  * embed
 150  *    YANG module embedding structure to register.  (static global provided
 151  *    by caller.)
 152  */
 153 extern void yang_module_embed(struct yang_module_embed *embed);
 154
 155 /*
 156  * Iterate recursively over all children of a schema node.
 157  *
 158  * snode
 159  *    YANG schema node to operate on.
 160  *
 161  * cb
 162  *    Function to call with each schema node.
 163  *
 164  * flags
 165  *    YANG_ITER_* flags to control how the iteration is performed.
 166  *
 167  * arg
 168  *    Arbitrary argument passed as the second parameter in each call to 'cb'.
 169  *
 170  * Returns:
 171  *    The return value of the last called callback.
 172  */
 173 extern int yang_snodes_iterate_subtree(const struct lys_node *snode,
 174                                        yang_iterate_cb cb, uint16_t flags,
 175                                        void *arg);
 176
 177 /*
 178  * Iterate over all libyang schema nodes from the given YANG module.
 179  *
 180  * module
 181  *    YANG module to operate on.
 182  *
 183  * cb
 184  *    Function to call with each schema node.
 185  *
 186  * flags
 187  *    YANG_ITER_* flags to control how the iteration is performed.
 188  *
 189  * arg
 190  *    Arbitrary argument passed as the second parameter in each call to 'cb'.
 191  *
 192  * Returns:
 193  *    The return value of the last called callback.
 194  */
 195 extern int yang_snodes_iterate_module(const struct lys_module *module,
 196                                       yang_iterate_cb cb, uint16_t flags,
 197                                       void *arg);
 198
 199 /*
 200  * Iterate over all libyang schema nodes from all loaded YANG modules.
 201  *
 202  * cb
 203  *    Function to call with each schema node.
 204  *
 205  * flags
 206  *    YANG_ITER_* flags to control how the iteration is performed.
 207  *
 208  * arg
 209  *    Arbitrary argument passed as the second parameter in each call to 'cb'.
 210  *
 211  * Returns:
 212  *    The return value of the last called callback.
 213  */
 214 extern int yang_snodes_iterate_all(yang_iterate_cb cb, uint16_t flags,
 215                                    void *arg);
 216
 217 /*
 218  * Build schema path or data path of the schema node.
 219  *
 220  * snode
 221  *    libyang schema node to be processed.
 222  *
 223  * type
 224  *    Specify whether a schema path or a data path should be built.
 225  *
 226  * xpath
 227  *    Pointer to previously allocated buffer.
 228  *
 229  * xpath_len
 230  *    Size of the xpath buffer.
 231  */
 232 extern void yang_snode_get_path(const struct lys_node *snode,
 233                                 enum yang_path_type type, char *xpath,
 234                                 size_t xpath_len);
 235
 236 /*
 237  * Find first parent schema node which is a presence-container or a list
 238  * (non-presence containers are ignored).
 239  *
 240  * snode
 241  *    libyang schema node to operate on.
 242  *
 243  * Returns:
 244  *    The parent libyang schema node if found, or NULL if not found.
 245  */
 246 extern struct lys_node *yang_snode_real_parent(const struct lys_node *snode);
 247
 248 /*
 249  * Find first parent schema node which is a list.
 250  *
 251  * snode
 252  *    libyang schema node to operate on.
 253  *
 254  * Returns:
 255  *    The parent libyang schema node (list) if found, or NULL if not found.
 256  */
 257 extern struct lys_node *yang_snode_parent_list(const struct lys_node *snode);
 258
 259 /*
 260  * Check if the libyang schema node represents typeless data (e.g. containers,
 261  * leafs of type empty, etc).
 262  *
 263  * snode
 264  *    libyang schema node to operate on.
 265  *
 266  * Returns:
 267  *    true if the schema node represents typeless data, false otherwise.
 268  */
 269 extern bool yang_snode_is_typeless_data(const struct lys_node *snode);
 270
 271 /*
 272  * Get the default value associated to a YANG leaf or leaf-list.
 273  *
 274  * snode
 275  *    libyang schema node to operate on.
 276  *
 277  * Returns:
 278  *    The default value if it exists, NULL otherwise.
 279  */
 280 extern const char *yang_snode_get_default(const struct lys_node *snode);
 281
 282 /*
 283  * Get the type structure of a leaf of leaf-list. If the type is a leafref, the
 284  * final (if there is a chain of leafrefs) target's type is found.
 285  *
 286  * snode
 287  *    libyang schema node to operate on.
 288  *
 289  * Returns:
 290  *    The found type if the schema node represents a leaf or a leaf-list, NULL
 291  *    otherwise.
 292  */
 293 extern const struct lys_type *yang_snode_get_type(const struct lys_node *snode);
 294
 295 /*
 296  * Build data path of the data node.
 297  *
 298  * dnode
 299  *    libyang data node to be processed.
 300  *
 301  * xpath
 302  *    Pointer to previously allocated buffer.
 303  *
 304  * xpath_len
 305  *    Size of the xpath buffer.
 306  */
 307 extern void yang_dnode_get_path(const struct lyd_node *dnode, char *xpath,
 308                                 size_t xpath_len);
 309
 310 /*
 311  * Find a libyang data node by its YANG data path.
 312  *
 313  * dnode
 314  *    Base libyang data node to operate on.
 315  *
 316  * xpath_fmt
 317  *    XPath expression (absolute or relative).
 318  *
 319  * Returns:
 320  *    The libyang data node if found, or NULL if not found.
 321  */
 322 extern struct lyd_node *yang_dnode_get(const struct lyd_node *dnode,
 323                                        const char *xpath_fmt, ...);
 324
 325 /*
 326  * Check if a libyang data node exists.
 327  *
 328  * dnode
 329  *    Base libyang data node to operate on.
 330  *
 331  * xpath_fmt
 332  *    XPath expression (absolute or relative).
 333  *
 334  * Returns:
 335  *    true if the libyang data node was found, false otherwise.
 336  */
 337 extern bool yang_dnode_exists(const struct lyd_node *dnode,
 338                               const char *xpath_fmt, ...);
 339
 340 /*
 341  * Check if the libyang data node contains a default value. Non-presence
 342  * containers are assumed to always contain a default value.
 343  *
 344  * dnode
 345  *    Base libyang data node to operate on.
 346  *
 347  * xpath_fmt
 348  *    Optional XPath expression (absolute or relative) to specify a different
 349  *    data node to operate on in the same data tree.
 350  *
 351  * Returns:
 352  *    true if the data node contains the default value, false otherwise.
 353  */
 354 extern bool yang_dnode_is_default(const struct lyd_node *dnode,
 355                                   const char *xpath_fmt, ...);
 356
 357 /*
 358  * Check if the libyang data node and all of its children contain default
 359  * values. Non-presence containers are assumed to always contain a default
 360  * value.
 361  *
 362  * dnode
 363  *    libyang data node to operate on.
 364  *
 365  * Returns:
 366  *    true if the data node and all of its children contain default values,
 367  *    false otherwise.
 368  */
 369 extern bool yang_dnode_is_default_recursive(const struct lyd_node *dnode);
 370
 371 /*
 372  * Change the value of a libyang leaf node.
 373  *
 374  * dnode
 375  *    libyang data node to operate on.
 376  *
 377  * value
 378  *    String representing the new value.
 379  */
 380 extern void yang_dnode_change_leaf(struct lyd_node *dnode, const char *value);
 381
 382 /*
 383  * Set the libyang private pointer to a user pointer. Can only be used on YANG
 384  * lists and containers.
 385  *
 386  * dnode
 387  *    libyang data node to operate on.
 388  *
 389  * entry
 390  *    Arbitrary user-specified pointer.
 391  */
 392 extern void yang_dnode_set_entry(const struct lyd_node *dnode, void *entry);
 393
 394 /*
 395  * Find the closest data node that contains an user pointer and return it.
 396  *
 397  * dnode
 398  *    libyang data node to operate on.
 399  *
 400  * Returns:
 401  *    User pointer if found, NULL otherwise.
 402  */
 403 extern void *yang_dnode_get_entry(const struct lyd_node *dnode);
 404
 405 /*
 406  * Create a new libyang data node.
 407  *
 408  * ly_ctx
 409  *    libyang context to operate on.
 410  *
 411  * config
 412  *    Specify whether the data node will contain only configuration data (true)
 413  *    or both configuration data and state data (false).
 414  *
 415  * Returns:
 416  *    Pointer to newly created libyang data node.
 417  */
 418 extern struct lyd_node *yang_dnode_new(struct ly_ctx *ly_ctx, bool config_only);
 419
 420 /*
 421  * Duplicate a libyang data node.
 422  *
 423  * dnode
 424  *    libyang data node to duplicate.
 425  *
 426  * Returns:
 427  *    Pointer to duplicated libyang data node.
 428  */
 429 extern struct lyd_node *yang_dnode_dup(const struct lyd_node *dnode);
 430
 431 /*
 432  * Delete a libyang data node.
 433  *
 434  * dnode
 435  *    Pointer to the libyang data node that is going to be deleted.
 436  */
 437 extern void yang_dnode_free(struct lyd_node *dnode);
 438
 439 /*
 440  * Create a new yang_data structure.
 441  *
 442  * xpath
 443  *    Data path of the YANG data.
 444  *
 445  * value
 446  *    String representing the value of the YANG data.
 447  *
 448  * Returns:
 449  *    Pointer to newly created yang_data structure.
 450  */
 451 extern struct yang_data *yang_data_new(const char *xpath, const char *value);
 452
 453 /*
 454  * Delete a yang_data structure.
 455  *
 456  * data
 457  *    yang_data to delete.
 458  */
 459 extern void yang_data_free(struct yang_data *data);
 460
 461 /*
 462  * Create a new linked list of yang_data structures. The list 'del' callback is
 463  * initialized appropriately so that the entire list can be deleted safely with
 464  * list_delete_and_null().
 465  *
 466  * Returns:
 467  *    Pointer to newly created linked list.
 468  */
 469 extern struct list *yang_data_list_new(void);
 470
 471 /*
 472  * Initialize the YANG subsystem. Should be called only once during the
 473  * daemon initialization process.
 474  */
 475 extern void yang_init(void);
 476
 477 /*
 478  * Finish the YANG subsystem gracefully. Should be called only when the daemon
 479  * is exiting.
 480  */
 481 extern void yang_terminate(void);
 482
 483 #endif /* _FRR_YANG_H_ */