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