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 atttribute type 148 149 Represents a single attribute type within an attr space. 150 151 Attributes: 152 value numerical ID when serialized 153 attr_set Attribute Set containing this attr 154 is_multi bool, attr may repeat multiple times 155 struct_name string, name of struct definition 156 sub_type string, name of sub type 157 len integer, optional byte length of binary types 158 display_hint string, hint to help choose format specifier 159 when displaying the value 160 """ 161 def __init__(self, family, attr_set, yaml, value): 162 super().__init__(family, yaml) 163 164 self.value = value 165 self.attr_set = attr_set 166 self.is_multi = yaml.get('multi-attr', False) 167 self.struct_name = yaml.get('struct') 168 self.sub_type = yaml.get('sub-type') 169 self.byte_order = yaml.get('byte-order') 170 self.len = yaml.get('len') 171 self.display_hint = yaml.get('display-hint') 172 173 174class SpecAttrSet(SpecElement): 175 """ Netlink Attribute Set class. 176 177 Represents a ID space of attributes within Netlink. 178 179 Note that unlike other elements, which expose contents of the raw spec 180 via the dictionary interface Attribute Set exposes attributes by name. 181 182 Attributes: 183 attrs ordered dict of all attributes (indexed by name) 184 attrs_by_val ordered dict of all attributes (indexed by value) 185 subset_of parent set if this is a subset, otherwise None 186 """ 187 def __init__(self, family, yaml): 188 super().__init__(family, yaml) 189 190 self.subset_of = self.yaml.get('subset-of', None) 191 192 self.attrs = collections.OrderedDict() 193 self.attrs_by_val = collections.OrderedDict() 194 195 if self.subset_of is None: 196 val = 1 197 for elem in self.yaml['attributes']: 198 if 'value' in elem: 199 val = elem['value'] 200 201 attr = self.new_attr(elem, val) 202 self.attrs[attr.name] = attr 203 self.attrs_by_val[attr.value] = attr 204 val += 1 205 else: 206 real_set = family.attr_sets[self.subset_of] 207 for elem in self.yaml['attributes']: 208 attr = real_set[elem['name']] 209 self.attrs[attr.name] = attr 210 self.attrs_by_val[attr.value] = attr 211 212 def new_attr(self, elem, value): 213 return SpecAttr(self.family, self, elem, value) 214 215 def __getitem__(self, key): 216 return self.attrs[key] 217 218 def __contains__(self, key): 219 return key in self.attrs 220 221 def __iter__(self): 222 yield from self.attrs 223 224 def items(self): 225 return self.attrs.items() 226 227 228class SpecStructMember(SpecElement): 229 """Struct member attribute 230 231 Represents a single struct member attribute. 232 233 Attributes: 234 type string, type of the member attribute 235 byte_order string or None for native byte order 236 enum string, name of the enum definition 237 len integer, optional byte length of binary types 238 display_hint string, hint to help choose format specifier 239 when displaying the value 240 """ 241 def __init__(self, family, yaml): 242 super().__init__(family, yaml) 243 self.type = yaml['type'] 244 self.byte_order = yaml.get('byte-order') 245 self.enum = yaml.get('enum') 246 self.len = yaml.get('len') 247 self.display_hint = yaml.get('display-hint') 248 249 250class SpecStruct(SpecElement): 251 """Netlink struct type 252 253 Represents a C struct definition. 254 255 Attributes: 256 members ordered list of struct members 257 """ 258 def __init__(self, family, yaml): 259 super().__init__(family, yaml) 260 261 self.members = [] 262 for member in yaml.get('members', []): 263 self.members.append(self.new_member(family, member)) 264 265 def new_member(self, family, elem): 266 return SpecStructMember(family, elem) 267 268 def __iter__(self): 269 yield from self.members 270 271 def items(self): 272 return self.members.items() 273 274 275class SpecOperation(SpecElement): 276 """Netlink Operation 277 278 Information about a single Netlink operation. 279 280 Attributes: 281 value numerical ID when serialized, None if req/rsp values differ 282 283 req_value numerical ID when serialized, user -> kernel 284 rsp_value numerical ID when serialized, user <- kernel 285 is_call bool, whether the operation is a call 286 is_async bool, whether the operation is a notification 287 is_resv bool, whether the operation does not exist (it's just a reserved ID) 288 attr_set attribute set name 289 fixed_header string, optional name of fixed header struct 290 291 yaml raw spec as loaded from the spec file 292 """ 293 def __init__(self, family, yaml, req_value, rsp_value): 294 super().__init__(family, yaml) 295 296 self.value = req_value if req_value == rsp_value else None 297 self.req_value = req_value 298 self.rsp_value = rsp_value 299 300 self.is_call = 'do' in yaml or 'dump' in yaml 301 self.is_async = 'notify' in yaml or 'event' in yaml 302 self.is_resv = not self.is_async and not self.is_call 303 self.fixed_header = self.yaml.get('fixed-header', family.fixed_header) 304 305 # Added by resolve: 306 self.attr_set = None 307 delattr(self, "attr_set") 308 309 def resolve(self): 310 self.resolve_up(super()) 311 312 if 'attribute-set' in self.yaml: 313 attr_set_name = self.yaml['attribute-set'] 314 elif 'notify' in self.yaml: 315 msg = self.family.msgs[self.yaml['notify']] 316 attr_set_name = msg['attribute-set'] 317 elif self.is_resv: 318 attr_set_name = '' 319 else: 320 raise Exception(f"Can't resolve attribute set for op '{self.name}'") 321 if attr_set_name: 322 self.attr_set = self.family.attr_sets[attr_set_name] 323 324 325class SpecFamily(SpecElement): 326 """ Netlink Family Spec class. 327 328 Netlink family information loaded from a spec (e.g. in YAML). 329 Takes care of unfolding implicit information which can be skipped 330 in the spec itself for brevity. 331 332 The class can be used like a dictionary to access the raw spec 333 elements but that's usually a bad idea. 334 335 Attributes: 336 proto protocol type (e.g. genetlink) 337 msg_id_model enum-model for operations (unified, directional etc.) 338 license spec license (loaded from an SPDX tag on the spec) 339 340 attr_sets dict of attribute sets 341 msgs dict of all messages (index by name) 342 ops dict of all valid requests / responses 343 ntfs dict of all async events 344 consts dict of all constants/enums 345 fixed_header string, optional name of family default fixed header struct 346 """ 347 def __init__(self, spec_path, schema_path=None, exclude_ops=None): 348 with open(spec_path, "r") as stream: 349 prefix = '# SPDX-License-Identifier: ' 350 first = stream.readline().strip() 351 if not first.startswith(prefix): 352 raise Exception('SPDX license tag required in the spec') 353 self.license = first[len(prefix):] 354 355 stream.seek(0) 356 spec = yaml.safe_load(stream) 357 358 self._resolution_list = [] 359 360 super().__init__(self, spec) 361 362 self._exclude_ops = exclude_ops if exclude_ops else [] 363 364 self.proto = self.yaml.get('protocol', 'genetlink') 365 self.msg_id_model = self.yaml['operations'].get('enum-model', 'unified') 366 367 if schema_path is None: 368 schema_path = os.path.dirname(os.path.dirname(spec_path)) + f'/{self.proto}.yaml' 369 if schema_path: 370 global jsonschema 371 372 with open(schema_path, "r") as stream: 373 schema = yaml.safe_load(stream) 374 375 if jsonschema is None: 376 jsonschema = importlib.import_module("jsonschema") 377 378 jsonschema.validate(self.yaml, schema) 379 380 self.attr_sets = collections.OrderedDict() 381 self.msgs = collections.OrderedDict() 382 self.req_by_value = collections.OrderedDict() 383 self.rsp_by_value = collections.OrderedDict() 384 self.ops = collections.OrderedDict() 385 self.ntfs = collections.OrderedDict() 386 self.consts = collections.OrderedDict() 387 388 last_exception = None 389 while len(self._resolution_list) > 0: 390 resolved = [] 391 unresolved = self._resolution_list 392 self._resolution_list = [] 393 394 for elem in unresolved: 395 try: 396 elem.resolve() 397 except (KeyError, AttributeError) as e: 398 self._resolution_list.append(elem) 399 last_exception = e 400 continue 401 402 resolved.append(elem) 403 404 if len(resolved) == 0: 405 raise last_exception 406 407 def new_enum(self, elem): 408 return SpecEnumSet(self, elem) 409 410 def new_attr_set(self, elem): 411 return SpecAttrSet(self, elem) 412 413 def new_struct(self, elem): 414 return SpecStruct(self, elem) 415 416 def new_operation(self, elem, req_val, rsp_val): 417 return SpecOperation(self, elem, req_val, rsp_val) 418 419 def add_unresolved(self, elem): 420 self._resolution_list.append(elem) 421 422 def _dictify_ops_unified(self): 423 self.fixed_header = self.yaml['operations'].get('fixed-header') 424 val = 1 425 for elem in self.yaml['operations']['list']: 426 if 'value' in elem: 427 val = elem['value'] 428 429 op = self.new_operation(elem, val, val) 430 val += 1 431 432 self.msgs[op.name] = op 433 434 def _dictify_ops_directional(self): 435 self.fixed_header = self.yaml['operations'].get('fixed-header') 436 req_val = rsp_val = 1 437 for elem in self.yaml['operations']['list']: 438 if 'notify' in elem or 'event' in elem: 439 if 'value' in elem: 440 rsp_val = elem['value'] 441 req_val_next = req_val 442 rsp_val_next = rsp_val + 1 443 req_val = None 444 elif 'do' in elem or 'dump' in elem: 445 mode = elem['do'] if 'do' in elem else elem['dump'] 446 447 v = mode.get('request', {}).get('value', None) 448 if v: 449 req_val = v 450 v = mode.get('reply', {}).get('value', None) 451 if v: 452 rsp_val = v 453 454 rsp_inc = 1 if 'reply' in mode else 0 455 req_val_next = req_val + 1 456 rsp_val_next = rsp_val + rsp_inc 457 else: 458 raise Exception("Can't parse directional ops") 459 460 if req_val == req_val_next: 461 req_val = None 462 if rsp_val == rsp_val_next: 463 rsp_val = None 464 465 skip = False 466 for exclude in self._exclude_ops: 467 skip |= bool(exclude.match(elem['name'])) 468 if not skip: 469 op = self.new_operation(elem, req_val, rsp_val) 470 471 req_val = req_val_next 472 rsp_val = rsp_val_next 473 474 self.msgs[op.name] = op 475 476 def find_operation(self, name): 477 """ 478 For a given operation name, find and return operation spec. 479 """ 480 for op in self.yaml['operations']['list']: 481 if name == op['name']: 482 return op 483 return None 484 485 def resolve(self): 486 self.resolve_up(super()) 487 488 definitions = self.yaml.get('definitions', []) 489 for elem in definitions: 490 if elem['type'] == 'enum' or elem['type'] == 'flags': 491 self.consts[elem['name']] = self.new_enum(elem) 492 elif elem['type'] == 'struct': 493 self.consts[elem['name']] = self.new_struct(elem) 494 else: 495 self.consts[elem['name']] = elem 496 497 for elem in self.yaml['attribute-sets']: 498 attr_set = self.new_attr_set(elem) 499 self.attr_sets[elem['name']] = attr_set 500 501 if self.msg_id_model == 'unified': 502 self._dictify_ops_unified() 503 elif self.msg_id_model == 'directional': 504 self._dictify_ops_directional() 505 506 for op in self.msgs.values(): 507 if op.req_value is not None: 508 self.req_by_value[op.req_value] = op 509 if op.rsp_value is not None: 510 self.rsp_by_value[op.rsp_value] = op 511 if not op.is_async and 'attribute-set' in op: 512 self.ops[op.name] = op 513 elif op.is_async: 514 self.ntfs[op.name] = op 515