1# SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause 2 3import collections 4import importlib 5import os 6import yaml 7 8 9# To be loaded dynamically as needed 10jsonschema = None 11 12 13class SpecElement: 14 """Netlink spec element. 15 16 Abstract element of the Netlink spec. Implements the dictionary interface 17 for access to the raw spec. Supports iterative resolution of dependencies 18 across elements and class inheritance levels. The elements of the spec 19 may refer to each other, and although loops should be very rare, having 20 to maintain correct ordering of instantiation is painful, so the resolve() 21 method should be used to perform parts of init which require access to 22 other parts of the spec. 23 24 Attributes: 25 yaml raw spec as loaded from the spec file 26 family back reference to the full family 27 28 name name of the entity as listed in the spec (optional) 29 ident_name name which can be safely used as identifier in code (optional) 30 """ 31 def __init__(self, family, yaml): 32 self.yaml = yaml 33 self.family = family 34 35 if 'name' in self.yaml: 36 self.name = self.yaml['name'] 37 self.ident_name = self.name.replace('-', '_') 38 39 self._super_resolved = False 40 family.add_unresolved(self) 41 42 def __getitem__(self, key): 43 return self.yaml[key] 44 45 def __contains__(self, key): 46 return key in self.yaml 47 48 def get(self, key, default=None): 49 return self.yaml.get(key, default) 50 51 def resolve_up(self, up): 52 if not self._super_resolved: 53 up.resolve() 54 self._super_resolved = True 55 56 def resolve(self): 57 pass 58 59 60class SpecEnumEntry(SpecElement): 61 """ Entry within an enum declared in the Netlink spec. 62 63 Attributes: 64 doc documentation string 65 enum_set back reference to the enum 66 value numerical value of this enum (use accessors in most situations!) 67 68 Methods: 69 raw_value raw value, i.e. the id in the enum, unlike user value which is a mask for flags 70 user_value user value, same as raw value for enums, for flags it's the mask 71 """ 72 def __init__(self, enum_set, yaml, prev, value_start): 73 if isinstance(yaml, str): 74 yaml = {'name': yaml} 75 super().__init__(enum_set.family, yaml) 76 77 self.doc = yaml.get('doc', '') 78 self.enum_set = enum_set 79 80 if 'value' in yaml: 81 self.value = yaml['value'] 82 elif prev: 83 self.value = prev.value + 1 84 else: 85 self.value = value_start 86 87 def has_doc(self): 88 return bool(self.doc) 89 90 def raw_value(self): 91 return self.value 92 93 def user_value(self, as_flags=None): 94 if self.enum_set['type'] == 'flags' or as_flags: 95 return 1 << self.value 96 else: 97 return self.value 98 99 100class SpecEnumSet(SpecElement): 101 """ Enum type 102 103 Represents an enumeration (list of numerical constants) 104 as declared in the "definitions" section of the spec. 105 106 Attributes: 107 type enum or flags 108 entries entries by name 109 entries_by_val entries by value 110 Methods: 111 get_mask for flags compute the mask of all defined values 112 """ 113 def __init__(self, family, yaml): 114 super().__init__(family, yaml) 115 116 self.type = yaml['type'] 117 118 prev_entry = None 119 value_start = self.yaml.get('value-start', 0) 120 self.entries = dict() 121 self.entries_by_val = dict() 122 for entry in self.yaml['entries']: 123 e = self.new_entry(entry, prev_entry, value_start) 124 self.entries[e.name] = e 125 self.entries_by_val[e.raw_value()] = e 126 prev_entry = e 127 128 def new_entry(self, entry, prev_entry, value_start): 129 return SpecEnumEntry(self, entry, prev_entry, value_start) 130 131 def has_doc(self): 132 if 'doc' in self.yaml: 133 return True 134 for entry in self.entries.values(): 135 if entry.has_doc(): 136 return True 137 return False 138 139 def get_mask(self, as_flags=None): 140 mask = 0 141 for e in self.entries.values(): 142 mask += e.user_value(as_flags) 143 return mask 144 145 146class SpecAttr(SpecElement): 147 """ Single Netlink attribute type 148 149 Represents a single attribute type within an attr space. 150 151 Attributes: 152 type string, attribute type 153 value numerical ID when serialized 154 attr_set Attribute Set containing this attr 155 is_multi bool, attr may repeat multiple times 156 struct_name string, name of struct definition 157 sub_type string, name of sub type 158 len integer, optional byte length of binary types 159 display_hint string, hint to help choose format specifier 160 when displaying the value 161 sub_message string, name of sub message type 162 selector string, name of attribute used to select 163 sub-message type 164 165 is_auto_scalar bool, attr is a variable-size scalar 166 """ 167 def __init__(self, family, attr_set, yaml, value): 168 super().__init__(family, yaml) 169 170 self.type = yaml['type'] 171 self.value = value 172 self.attr_set = attr_set 173 self.is_multi = yaml.get('multi-attr', False) 174 self.struct_name = yaml.get('struct') 175 self.sub_type = yaml.get('sub-type') 176 self.byte_order = yaml.get('byte-order') 177 self.len = yaml.get('len') 178 self.display_hint = yaml.get('display-hint') 179 self.sub_message = yaml.get('sub-message') 180 self.selector = yaml.get('selector') 181 182 self.is_auto_scalar = self.type == "sint" or self.type == "uint" 183 184 185class SpecAttrSet(SpecElement): 186 """ Netlink Attribute Set class. 187 188 Represents a ID space of attributes within Netlink. 189 190 Note that unlike other elements, which expose contents of the raw spec 191 via the dictionary interface Attribute Set exposes attributes by name. 192 193 Attributes: 194 attrs ordered dict of all attributes (indexed by name) 195 attrs_by_val ordered dict of all attributes (indexed by value) 196 subset_of parent set if this is a subset, otherwise None 197 """ 198 def __init__(self, family, yaml): 199 super().__init__(family, yaml) 200 201 self.subset_of = self.yaml.get('subset-of', None) 202 203 self.attrs = collections.OrderedDict() 204 self.attrs_by_val = collections.OrderedDict() 205 206 if self.subset_of is None: 207 val = 1 208 for elem in self.yaml['attributes']: 209 if 'value' in elem: 210 val = elem['value'] 211 212 attr = self.new_attr(elem, val) 213 self.attrs[attr.name] = attr 214 self.attrs_by_val[attr.value] = attr 215 val += 1 216 else: 217 real_set = family.attr_sets[self.subset_of] 218 for elem in self.yaml['attributes']: 219 attr = real_set[elem['name']] 220 self.attrs[attr.name] = attr 221 self.attrs_by_val[attr.value] = attr 222 223 def new_attr(self, elem, value): 224 return SpecAttr(self.family, self, elem, value) 225 226 def __getitem__(self, key): 227 return self.attrs[key] 228 229 def __contains__(self, key): 230 return key in self.attrs 231 232 def __iter__(self): 233 yield from self.attrs 234 235 def items(self): 236 return self.attrs.items() 237 238 239class SpecStructMember(SpecElement): 240 """Struct member attribute 241 242 Represents a single struct member attribute. 243 244 Attributes: 245 type string, type of the member attribute 246 byte_order string or None for native byte order 247 enum string, name of the enum definition 248 len integer, optional byte length of binary types 249 display_hint string, hint to help choose format specifier 250 when displaying the value 251 struct string, name of nested struct type 252 """ 253 def __init__(self, family, yaml): 254 super().__init__(family, yaml) 255 self.type = yaml['type'] 256 self.byte_order = yaml.get('byte-order') 257 self.enum = yaml.get('enum') 258 self.len = yaml.get('len') 259 self.display_hint = yaml.get('display-hint') 260 self.struct = yaml.get('struct') 261 262 263class SpecStruct(SpecElement): 264 """Netlink struct type 265 266 Represents a C struct definition. 267 268 Attributes: 269 members ordered list of struct members 270 """ 271 def __init__(self, family, yaml): 272 super().__init__(family, yaml) 273 274 self.members = [] 275 for member in yaml.get('members', []): 276 self.members.append(self.new_member(family, member)) 277 278 def new_member(self, family, elem): 279 return SpecStructMember(family, elem) 280 281 def __iter__(self): 282 yield from self.members 283 284 def items(self): 285 return self.members.items() 286 287 288class SpecSubMessage(SpecElement): 289 """ Netlink sub-message definition 290 291 Represents a set of sub-message formats for polymorphic nlattrs 292 that contain type-specific sub messages. 293 294 Attributes: 295 name string, name of sub-message definition 296 formats dict of sub-message formats indexed by match value 297 """ 298 def __init__(self, family, yaml): 299 super().__init__(family, yaml) 300 301 self.formats = collections.OrderedDict() 302 for elem in self.yaml['formats']: 303 format = self.new_format(family, elem) 304 self.formats[format.value] = format 305 306 def new_format(self, family, format): 307 return SpecSubMessageFormat(family, format) 308 309 310class SpecSubMessageFormat(SpecElement): 311 """ Netlink sub-message format definition 312 313 Represents a single format for a sub-message. 314 315 Attributes: 316 value attribute value to match against type selector 317 fixed_header string, name of fixed header, or None 318 attr_set string, name of attribute set, or None 319 """ 320 def __init__(self, family, yaml): 321 super().__init__(family, yaml) 322 323 self.value = yaml.get('value') 324 self.fixed_header = yaml.get('fixed-header') 325 self.attr_set = yaml.get('attribute-set') 326 327 328class SpecOperation(SpecElement): 329 """Netlink Operation 330 331 Information about a single Netlink operation. 332 333 Attributes: 334 value numerical ID when serialized, None if req/rsp values differ 335 336 req_value numerical ID when serialized, user -> kernel 337 rsp_value numerical ID when serialized, user <- kernel 338 modes supported operation modes (do, dump, event etc.) 339 is_call bool, whether the operation is a call 340 is_async bool, whether the operation is a notification 341 is_resv bool, whether the operation does not exist (it's just a reserved ID) 342 attr_set attribute set name 343 fixed_header string, optional name of fixed header struct 344 345 yaml raw spec as loaded from the spec file 346 """ 347 def __init__(self, family, yaml, req_value, rsp_value): 348 super().__init__(family, yaml) 349 350 self.value = req_value if req_value == rsp_value else None 351 self.req_value = req_value 352 self.rsp_value = rsp_value 353 354 self.modes = yaml.keys() & {'do', 'dump', 'event', 'notify'} 355 self.is_call = 'do' in yaml or 'dump' in yaml 356 self.is_async = 'notify' in yaml or 'event' in yaml 357 self.is_resv = not self.is_async and not self.is_call 358 self.fixed_header = self.yaml.get('fixed-header', family.fixed_header) 359 360 # Added by resolve: 361 self.attr_set = None 362 delattr(self, "attr_set") 363 364 def resolve(self): 365 self.resolve_up(super()) 366 367 if 'attribute-set' in self.yaml: 368 attr_set_name = self.yaml['attribute-set'] 369 elif 'notify' in self.yaml: 370 msg = self.family.msgs[self.yaml['notify']] 371 attr_set_name = msg['attribute-set'] 372 elif self.is_resv: 373 attr_set_name = '' 374 else: 375 raise Exception(f"Can't resolve attribute set for op '{self.name}'") 376 if attr_set_name: 377 self.attr_set = self.family.attr_sets[attr_set_name] 378 379 380class SpecMcastGroup(SpecElement): 381 """Netlink Multicast Group 382 383 Information about a multicast group. 384 385 Value is only used for classic netlink families that use the 386 netlink-raw schema. Genetlink families use dynamic ID allocation 387 where the ids of multicast groups get resolved at runtime. Value 388 will be None for genetlink families. 389 390 Attributes: 391 name name of the mulitcast group 392 value integer id of this multicast group for netlink-raw or None 393 yaml raw spec as loaded from the spec file 394 """ 395 def __init__(self, family, yaml): 396 super().__init__(family, yaml) 397 self.value = self.yaml.get('value') 398 399 400class SpecFamily(SpecElement): 401 """ Netlink Family Spec class. 402 403 Netlink family information loaded from a spec (e.g. in YAML). 404 Takes care of unfolding implicit information which can be skipped 405 in the spec itself for brevity. 406 407 The class can be used like a dictionary to access the raw spec 408 elements but that's usually a bad idea. 409 410 Attributes: 411 proto protocol type (e.g. genetlink) 412 msg_id_model enum-model for operations (unified, directional etc.) 413 license spec license (loaded from an SPDX tag on the spec) 414 415 attr_sets dict of attribute sets 416 msgs dict of all messages (index by name) 417 sub_msgs dict of all sub messages (index by name) 418 ops dict of all valid requests / responses 419 ntfs dict of all async events 420 consts dict of all constants/enums 421 fixed_header string, optional name of family default fixed header struct 422 mcast_groups dict of all multicast groups (index by name) 423 kernel_family dict of kernel family attributes 424 """ 425 def __init__(self, spec_path, schema_path=None, exclude_ops=None): 426 with open(spec_path, "r") as stream: 427 prefix = '# SPDX-License-Identifier: ' 428 first = stream.readline().strip() 429 if not first.startswith(prefix): 430 raise Exception('SPDX license tag required in the spec') 431 self.license = first[len(prefix):] 432 433 stream.seek(0) 434 spec = yaml.safe_load(stream) 435 436 self._resolution_list = [] 437 438 super().__init__(self, spec) 439 440 self._exclude_ops = exclude_ops if exclude_ops else [] 441 442 self.proto = self.yaml.get('protocol', 'genetlink') 443 self.msg_id_model = self.yaml['operations'].get('enum-model', 'unified') 444 445 if schema_path is None: 446 schema_path = os.path.dirname(os.path.dirname(spec_path)) + f'/{self.proto}.yaml' 447 if schema_path: 448 global jsonschema 449 450 with open(schema_path, "r") as stream: 451 schema = yaml.safe_load(stream) 452 453 if jsonschema is None: 454 jsonschema = importlib.import_module("jsonschema") 455 456 jsonschema.validate(self.yaml, schema) 457 458 self.attr_sets = collections.OrderedDict() 459 self.sub_msgs = collections.OrderedDict() 460 self.msgs = collections.OrderedDict() 461 self.req_by_value = collections.OrderedDict() 462 self.rsp_by_value = collections.OrderedDict() 463 self.ops = collections.OrderedDict() 464 self.ntfs = collections.OrderedDict() 465 self.consts = collections.OrderedDict() 466 self.mcast_groups = collections.OrderedDict() 467 self.kernel_family = collections.OrderedDict(self.yaml.get('kernel-family', {})) 468 469 last_exception = None 470 while len(self._resolution_list) > 0: 471 resolved = [] 472 unresolved = self._resolution_list 473 self._resolution_list = [] 474 475 for elem in unresolved: 476 try: 477 elem.resolve() 478 except (KeyError, AttributeError) as e: 479 self._resolution_list.append(elem) 480 last_exception = e 481 continue 482 483 resolved.append(elem) 484 485 if len(resolved) == 0: 486 raise last_exception 487 488 def new_enum(self, elem): 489 return SpecEnumSet(self, elem) 490 491 def new_attr_set(self, elem): 492 return SpecAttrSet(self, elem) 493 494 def new_struct(self, elem): 495 return SpecStruct(self, elem) 496 497 def new_sub_message(self, elem): 498 return SpecSubMessage(self, elem); 499 500 def new_operation(self, elem, req_val, rsp_val): 501 return SpecOperation(self, elem, req_val, rsp_val) 502 503 def new_mcast_group(self, elem): 504 return SpecMcastGroup(self, elem) 505 506 def add_unresolved(self, elem): 507 self._resolution_list.append(elem) 508 509 def _dictify_ops_unified(self): 510 self.fixed_header = self.yaml['operations'].get('fixed-header') 511 val = 1 512 for elem in self.yaml['operations']['list']: 513 if 'value' in elem: 514 val = elem['value'] 515 516 op = self.new_operation(elem, val, val) 517 val += 1 518 519 self.msgs[op.name] = op 520 521 def _dictify_ops_directional(self): 522 self.fixed_header = self.yaml['operations'].get('fixed-header') 523 req_val = rsp_val = 1 524 for elem in self.yaml['operations']['list']: 525 if 'notify' in elem or 'event' in elem: 526 if 'value' in elem: 527 rsp_val = elem['value'] 528 req_val_next = req_val 529 rsp_val_next = rsp_val + 1 530 req_val = None 531 elif 'do' in elem or 'dump' in elem: 532 mode = elem['do'] if 'do' in elem else elem['dump'] 533 534 v = mode.get('request', {}).get('value', None) 535 if v: 536 req_val = v 537 v = mode.get('reply', {}).get('value', None) 538 if v: 539 rsp_val = v 540 541 rsp_inc = 1 if 'reply' in mode else 0 542 req_val_next = req_val + 1 543 rsp_val_next = rsp_val + rsp_inc 544 else: 545 raise Exception("Can't parse directional ops") 546 547 if req_val == req_val_next: 548 req_val = None 549 if rsp_val == rsp_val_next: 550 rsp_val = None 551 552 skip = False 553 for exclude in self._exclude_ops: 554 skip |= bool(exclude.match(elem['name'])) 555 if not skip: 556 op = self.new_operation(elem, req_val, rsp_val) 557 558 req_val = req_val_next 559 rsp_val = rsp_val_next 560 561 self.msgs[op.name] = op 562 563 def find_operation(self, name): 564 """ 565 For a given operation name, find and return operation spec. 566 """ 567 for op in self.yaml['operations']['list']: 568 if name == op['name']: 569 return op 570 return None 571 572 def resolve(self): 573 self.resolve_up(super()) 574 575 definitions = self.yaml.get('definitions', []) 576 for elem in definitions: 577 if elem['type'] == 'enum' or elem['type'] == 'flags': 578 self.consts[elem['name']] = self.new_enum(elem) 579 elif elem['type'] == 'struct': 580 self.consts[elem['name']] = self.new_struct(elem) 581 else: 582 self.consts[elem['name']] = elem 583 584 for elem in self.yaml['attribute-sets']: 585 attr_set = self.new_attr_set(elem) 586 self.attr_sets[elem['name']] = attr_set 587 588 for elem in self.yaml.get('sub-messages', []): 589 sub_message = self.new_sub_message(elem) 590 self.sub_msgs[sub_message.name] = sub_message 591 592 if self.msg_id_model == 'unified': 593 self._dictify_ops_unified() 594 elif self.msg_id_model == 'directional': 595 self._dictify_ops_directional() 596 597 for op in self.msgs.values(): 598 if op.req_value is not None: 599 self.req_by_value[op.req_value] = op 600 if op.rsp_value is not None: 601 self.rsp_by_value[op.rsp_value] = op 602 if not op.is_async and 'attribute-set' in op: 603 self.ops[op.name] = op 604 elif op.is_async: 605 self.ntfs[op.name] = op 606 607 mcgs = self.yaml.get('mcast-groups') 608 if mcgs: 609 for elem in mcgs['list']: 610 mcg = self.new_mcast_group(elem) 611 self.mcast_groups[elem['name']] = mcg 612