| #!/usr/bin/env python |
| # |
| # Copyright (c) 2016 Cisco and/or its affiliates. |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at: |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| # |
| |
| from __future__ import print_function |
| import sys, os, logging, collections, struct, json, threading, glob |
| import atexit |
| |
| logging.basicConfig(level=logging.DEBUG) |
| import vpp_api |
| |
| def eprint(*args, **kwargs): |
| """Print critical diagnostics to stderr.""" |
| print(*args, file=sys.stderr, **kwargs) |
| |
| def vpp_atexit(self): |
| """Clean up VPP connection on shutdown.""" |
| if self.connected: |
| eprint ('Cleaning up VPP on exit') |
| self.disconnect() |
| |
| class VPP(): |
| """VPP interface. |
| |
| This class provides the APIs to VPP. The APIs are loaded |
| from provided .api.json files and makes functions accordingly. |
| These functions are documented in the VPP .api files, as they |
| are dynamically created. |
| |
| Additionally, VPP can send callback messages; this class |
| provides a means to register a callback function to receive |
| these messages in a background thread. |
| """ |
| def __init__(self, apifiles = None, testmode = False): |
| """Create a VPP API object. |
| |
| apifiles is a list of files containing API |
| descriptions that will be loaded - methods will be |
| dynamically created reflecting these APIs. If not |
| provided this will load the API files from VPP's |
| default install location. |
| """ |
| self.messages = {} |
| self.id_names = [] |
| self.id_msgdef = [] |
| self.buffersize = 10000 |
| self.connected = False |
| self.header = struct.Struct('>HI') |
| self.results_lock = threading.Lock() |
| self.results = {} |
| self.timeout = 5 |
| self.apifiles = [] |
| self.event_callback = None |
| |
| if not apifiles: |
| # Pick up API definitions from default directory |
| apifiles = glob.glob('/usr/share/vpp/api/*.api.json') |
| |
| for file in apifiles: |
| with open(file) as apidef_file: |
| api = json.load(apidef_file) |
| for t in api['types']: |
| self.add_type(t[0], t[1:]) |
| |
| for m in api['messages']: |
| self.add_message(m[0], m[1:]) |
| self.apifiles = apifiles |
| |
| # Basic sanity check |
| if len(self.messages) == 0 and not testmode: |
| raise ValueError(1, 'Missing JSON message definitions') |
| |
| # Make sure we allow VPP to clean up the message rings. |
| atexit.register(vpp_atexit, self) |
| |
| class ContextId(object): |
| """Thread-safe provider of unique context IDs.""" |
| def __init__(self): |
| self.context = 0 |
| self.lock = threading.Lock() |
| def __call__(self): |
| """Get a new unique (or, at least, not recently used) context.""" |
| with self.lock: |
| self.context += 1 |
| return self.context |
| get_context = ContextId() |
| |
| def status(self): |
| """Debug function: report current VPP API status to stdout.""" |
| print('Connected') if self.connected else print('Not Connected') |
| print('Read API definitions from', ', '.join(self.apifiles)) |
| |
| def __struct (self, t, n = None, e = -1, vl = None): |
| """Create a packing structure for a message.""" |
| base_types = { 'u8' : 'B', |
| 'u16' : 'H', |
| 'u32' : 'I', |
| 'i32' : 'i', |
| 'u64' : 'Q', |
| 'f64' : 'd', |
| } |
| pack = None |
| if t in base_types: |
| pack = base_types[t] |
| if not vl: |
| if e > 0 and t == 'u8': |
| # Fixed byte array |
| return struct.Struct('>' + str(e) + 's') |
| if e > 0: |
| # Fixed array of base type |
| return [e, struct.Struct('>' + base_types[t])] |
| elif e == 0: |
| # Old style variable array |
| return [-1, struct.Struct('>' + base_types[t])] |
| else: |
| # Variable length array |
| return [vl, struct.Struct('>s')] if t == 'u8' else \ |
| [vl, struct.Struct('>' + base_types[t])] |
| |
| return struct.Struct('>' + base_types[t]) |
| |
| if t in self.messages: |
| ### Return a list in case of array ### |
| if e > 0 and not vl: |
| return [e, lambda self, encode, buf, offset, args: ( |
| self.__struct_type(encode, self.messages[t], buf, offset, |
| args))] |
| if vl: |
| return [vl, lambda self, encode, buf, offset, args: ( |
| self.__struct_type(encode, self.messages[t], buf, offset, |
| args))] |
| elif e == 0: |
| # Old style VLA |
| raise NotImplementedError(1, 'No support for compound types ' + t) |
| return lambda self, encode, buf, offset, args: ( |
| self.__struct_type(encode, self.messages[t], buf, offset, args) |
| ) |
| |
| raise ValueError(1, 'Invalid message type: ' + t) |
| |
| def __struct_type(self, encode, msgdef, buf, offset, kwargs): |
| """Get a message packer or unpacker.""" |
| if encode: |
| return self.__struct_type_encode(msgdef, buf, offset, kwargs) |
| else: |
| return self.__struct_type_decode(msgdef, buf, offset) |
| |
| def __struct_type_encode(self, msgdef, buf, offset, kwargs): |
| off = offset |
| size = 0 |
| |
| for k in kwargs: |
| if k not in msgdef['args']: |
| raise ValueError(1, 'Invalid field-name in message call ' + k) |
| |
| for k,v in msgdef['args'].iteritems(): |
| off += size |
| if k in kwargs: |
| if type(v) is list: |
| if callable(v[1]): |
| e = kwargs[v[0]] if v[0] in kwargs else v[0] |
| size = 0 |
| for i in range(e): |
| size += v[1](self, True, buf, off + size, |
| kwargs[k][i]) |
| else: |
| if v[0] in kwargs: |
| l = kwargs[v[0]] |
| else: |
| l = len(kwargs[k]) |
| if v[1].size == 1: |
| buf[off:off + l] = bytearray(kwargs[k]) |
| size = l |
| else: |
| size = 0 |
| for i in kwargs[k]: |
| v[1].pack_into(buf, off + size, i) |
| size += v[1].size |
| else: |
| if callable(v): |
| size = v(self, True, buf, off, kwargs[k]) |
| else: |
| v.pack_into(buf, off, kwargs[k]) |
| size = v.size |
| else: |
| size = v.size if not type(v) is list else 0 |
| |
| return off + size - offset |
| |
| |
| def __getitem__(self, name): |
| if name in self.messages: |
| return self.messages[name] |
| return None |
| |
| def encode(self, msgdef, kwargs): |
| # Make suitably large buffer |
| buf = bytearray(self.buffersize) |
| offset = 0 |
| size = self.__struct_type(True, msgdef, buf, offset, kwargs) |
| return buf[:offset + size] |
| |
| def decode(self, msgdef, buf): |
| return self.__struct_type(False, msgdef, buf, 0, None)[1] |
| |
| def __struct_type_decode(self, msgdef, buf, offset): |
| res = [] |
| off = offset |
| size = 0 |
| for k,v in msgdef['args'].iteritems(): |
| off += size |
| if type(v) is list: |
| lst = [] |
| if callable(v[1]): # compound type |
| size = 0 |
| if v[0] in msgdef['args']: # vla |
| e = res[v[2]] |
| else: # fixed array |
| e = v[0] |
| res.append(lst) |
| for i in range(e): |
| (s,l) = v[1](self, False, buf, off + size, None) |
| lst.append(l) |
| size += s |
| continue |
| if v[1].size == 1: |
| if type(v[0]) is int: |
| size = len(buf) - off |
| else: |
| size = res[v[2]] |
| res.append(buf[off:off + size]) |
| else: |
| e = v[0] if type(v[0]) is int else res[v[2]] |
| if e == -1: |
| e = (len(buf) - off) / v[1].size |
| lst = [] |
| res.append(lst) |
| size = 0 |
| for i in range(e): |
| lst.append(v[1].unpack_from(buf, off + size)[0]) |
| size += v[1].size |
| else: |
| if callable(v): |
| (s,l) = v(self, False, buf, off, None) |
| res.append(l) |
| size += s |
| else: |
| res.append(v.unpack_from(buf, off)[0]) |
| size = v.size |
| |
| return off + size - offset, msgdef['return_tuple']._make(res) |
| |
| def ret_tup(self, name): |
| if name in self.messages and 'return_tuple' in self.messages[name]: |
| return self.messages[name]['return_tuple'] |
| return None |
| |
| def add_message(self, name, msgdef): |
| if name in self.messages: |
| raise ValueError('Duplicate message name: ' + name) |
| |
| args = collections.OrderedDict() |
| argtypes = collections.OrderedDict() |
| fields = [] |
| msg = {} |
| for i, f in enumerate(msgdef): |
| if type(f) is dict and 'crc' in f: |
| msg['crc'] = f['crc'] |
| continue |
| field_type = f[0] |
| field_name = f[1] |
| if len(f) == 3 and f[2] == 0 and i != len(msgdef) - 2: |
| raise ValueError('Variable Length Array must be last: ' + name) |
| args[field_name] = self.__struct(*f) |
| argtypes[field_name] = field_type |
| if len(f) == 4: # Find offset to # elements field |
| args[field_name].append(args.keys().index(f[3]) - i) |
| fields.append(field_name) |
| msg['return_tuple'] = collections.namedtuple(name, fields, |
| rename = True) |
| self.messages[name] = msg |
| self.messages[name]['args'] = args |
| self.messages[name]['argtypes'] = argtypes |
| return self.messages[name] |
| |
| def add_type(self, name, typedef): |
| return self.add_message('vl_api_' + name + '_t', typedef) |
| |
| def make_function(self, name, i, msgdef, multipart, async): |
| if (async): |
| f = lambda **kwargs: (self._call_vpp_async(i, msgdef, **kwargs)) |
| else: |
| f = lambda **kwargs: (self._call_vpp(i, msgdef, multipart, **kwargs)) |
| args = self.messages[name]['args'] |
| argtypes = self.messages[name]['argtypes'] |
| f.__name__ = str(name) |
| f.__doc__ = ", ".join(["%s %s" % (argtypes[k], k) for k in args.keys()]) |
| return f |
| |
| def _register_functions(self, async=False): |
| self.id_names = [None] * (self.vpp_dictionary_maxid + 1) |
| self.id_msgdef = [None] * (self.vpp_dictionary_maxid + 1) |
| for name, msgdef in self.messages.iteritems(): |
| if name in self.vpp_dictionary: |
| if self.messages[name]['crc'] != self.vpp_dictionary[name]['crc']: |
| raise ValueError(3, 'Failed CRC checksum ' + name + |
| ' ' + self.messages[name]['crc'] + |
| ' ' + self.vpp_dictionary[name]['crc']) |
| i = self.vpp_dictionary[name]['id'] |
| self.id_msgdef[i] = msgdef |
| self.id_names[i] = name |
| multipart = True if name.find('_dump') > 0 else False |
| setattr(self, name, self.make_function(name, i, msgdef, multipart, async)) |
| |
| def _write (self, buf): |
| """Send a binary-packed message to VPP.""" |
| if not self.connected: |
| raise IOError(1, 'Not connected') |
| return vpp_api.write(str(buf)) |
| |
| def _load_dictionary(self): |
| self.vpp_dictionary = {} |
| self.vpp_dictionary_maxid = 0 |
| d = vpp_api.msg_table() |
| |
| if not d: |
| raise IOError(3, 'Cannot get VPP API dictionary') |
| for i,n in d: |
| name, crc = n.rsplit('_', 1) |
| crc = '0x' + crc |
| self.vpp_dictionary[name] = { 'id' : i, 'crc' : crc } |
| self.vpp_dictionary_maxid = max(self.vpp_dictionary_maxid, i) |
| |
| def connect(self, name, chroot_prefix = None, async = False, rx_qlen = 32): |
| """Attach to VPP. |
| |
| name - the name of the client. |
| chroot_prefix - if VPP is chroot'ed, the prefix of the jail |
| async - if true, messages are sent without waiting for a reply |
| rx_qlen - the length of the VPP message receive queue between |
| client and server. |
| """ |
| msg_handler = self.msg_handler_sync if not async else self.msg_handler_async |
| if chroot_prefix is not None: |
| rv = vpp_api.connect(name, msg_handler, rx_qlen, chroot_prefix) |
| else: |
| rv = vpp_api.connect(name, msg_handler, rx_qlen) |
| |
| if rv != 0: |
| raise IOError(2, 'Connect failed') |
| self.connected = True |
| |
| self._load_dictionary() |
| self._register_functions(async=async) |
| |
| # Initialise control ping |
| self.control_ping_index = self.vpp_dictionary['control_ping']['id'] |
| self.control_ping_msgdef = self.messages['control_ping'] |
| |
| def disconnect(self): |
| """Detach from VPP.""" |
| rv = vpp_api.disconnect() |
| self.connected = False |
| return rv |
| |
| def results_wait(self, context): |
| """In a sync call, wait for the reply |
| |
| The context ID is used to pair reply to request. |
| """ |
| |
| # Results is filled by the background callback. It will |
| # raise the event when the context receives a response. |
| # Given there are two threads we have to be careful with the |
| # use of results and the structures under it, hence the lock. |
| with self.results_lock: |
| result = self.results[context] |
| ev = result['e'] |
| |
| timed_out = not ev.wait(self.timeout) |
| |
| if timed_out: |
| raise IOError(3, 'Waiting for reply timed out') |
| else: |
| with self.results_lock: |
| result = self.results[context] |
| del self.results[context] |
| return result['r'] |
| |
| def results_prepare(self, context, multi=False): |
| """Prep for receiving a result in response to a request msg |
| |
| context - unique context number sent in request and |
| returned in reply or replies |
| multi - true if we expect multiple messages from this |
| reply. |
| """ |
| |
| # The event is used to indicate that all results are in |
| new_result = { |
| 'e': threading.Event(), |
| } |
| if multi: |
| # Make it clear to the BG thread it's going to see several |
| # messages; messages are stored in a results array |
| new_result['m'] = True |
| new_result['r'] = [] |
| |
| new_result['e'].clear() |
| |
| # Put the prepped result structure into results, at which point |
| # the bg thread can also access it (hence the thread lock) |
| with self.results_lock: |
| self.results[context] = new_result |
| |
| def msg_handler_sync(self, msg): |
| """Process an incoming message from VPP in sync mode. |
| |
| The message may be a reply or it may be an async notification. |
| """ |
| r = self.decode_incoming_msg(msg) |
| if r is None: |
| return |
| |
| # If we have a context, then use the context to find any |
| # request waiting for a reply |
| context = 0 |
| if hasattr(r, 'context') and r.context > 0: |
| context = r.context |
| |
| msgname = type(r).__name__ |
| |
| if context == 0: |
| # No context -> async notification that we feed to the callback |
| if self.event_callback: |
| self.event_callback(msgname, r) |
| else: |
| # Context -> use the results structure (carefully) to find |
| # who we're responding to and return the message to that |
| # thread |
| with self.results_lock: |
| if context not in self.results: |
| eprint('Not expecting results for this context', context, r) |
| else: |
| result = self.results[context] |
| |
| # |
| # Collect results until control ping |
| # |
| |
| if msgname == 'control_ping_reply': |
| # End of a multipart |
| result['e'].set() |
| elif 'm' in self.results[context]: |
| # One element in a multipart |
| result['r'].append(r) |
| else: |
| # All of a single result |
| result['r'] = r |
| result['e'].set() |
| |
| def decode_incoming_msg(self, msg): |
| if not msg: |
| eprint('vpp_api.read failed') |
| return |
| |
| i, ci = self.header.unpack_from(msg, 0) |
| if self.id_names[i] == 'rx_thread_exit': |
| return |
| |
| # |
| # Decode message and returns a tuple. |
| # |
| msgdef = self.id_msgdef[i] |
| if not msgdef: |
| raise IOError(2, 'Reply message undefined') |
| |
| r = self.decode(msgdef, msg) |
| |
| return r |
| |
| def msg_handler_async(self, msg): |
| """Process a message from VPP in async mode. |
| |
| In async mode, all messages are returned to the callback. |
| """ |
| r = self.decode_incoming_msg(msg) |
| if r is None: |
| return |
| |
| msgname = type(r).__name__ |
| |
| if self.event_callback: |
| self.event_callback(msgname, r) |
| |
| def _control_ping(self, context): |
| """Send a ping command.""" |
| self._call_vpp_async(self.control_ping_index, |
| self.control_ping_msgdef, |
| context=context) |
| |
| def _call_vpp(self, i, msgdef, multipart, **kwargs): |
| """Given a message, send the message and await a reply. |
| |
| msgdef - the message packing definition |
| i - the message type index |
| multipart - True if the message returns multiple |
| messages in return. |
| context - context number - chosen at random if not |
| supplied. |
| The remainder of the kwargs are the arguments to the API call. |
| |
| The return value is the message or message array containing |
| the response. It will raise an IOError exception if there was |
| no response within the timeout window. |
| """ |
| |
| # We need a context if not supplied, in order to get the |
| # response |
| context = kwargs.get('context', self.get_context()) |
| kwargs['context'] = context |
| |
| # Set up to receive a response |
| self.results_prepare(context, multi=multipart) |
| |
| # Output the message |
| self._call_vpp_async(i, msgdef, **kwargs) |
| |
| if multipart: |
| # Send a ping after the request - we use its response |
| # to detect that we have seen all results. |
| self._control_ping(context) |
| |
| # Block until we get a reply. |
| r = self.results_wait(context) |
| |
| return r |
| |
| def _call_vpp_async(self, i, msgdef, **kwargs): |
| """Given a message, send the message and await a reply. |
| |
| msgdef - the message packing definition |
| i - the message type index |
| context - context number - chosen at random if not |
| supplied. |
| The remainder of the kwargs are the arguments to the API call. |
| """ |
| if not 'context' in kwargs: |
| context = self.get_context() |
| kwargs['context'] = context |
| else: |
| context = kwargs['context'] |
| kwargs['_vl_msg_id'] = i |
| b = self.encode(msgdef, kwargs) |
| |
| self._write(b) |
| |
| def register_event_callback(self, callback): |
| """Register a callback for async messages. |
| |
| This will be called for async notifications in sync mode, |
| and all messages in async mode. In sync mode, replies to |
| requests will not come here. |
| |
| callback is a fn(msg_type_name, msg_type) that will be |
| called when a message comes in. While this function is |
| executing, note that (a) you are in a background thread and |
| may wish to use threading.Lock to protect your datastructures, |
| and (b) message processing from VPP will stop (so if you take |
| a long while about it you may provoke reply timeouts or cause |
| VPP to fill the RX buffer). Passing None will disable the |
| callback. |
| """ |
| self.event_callback = callback |