| #!/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 |
| import os |
| import logging |
| import collections |
| import struct |
| import json |
| import threading |
| import glob |
| import atexit |
| from cffi import FFI |
| |
| if sys.version[0] == '2': |
| import Queue as queue |
| else: |
| import queue as queue |
| |
| ffi = FFI() |
| ffi.cdef(""" |
| typedef void (*vac_callback_t)(unsigned char * data, int len); |
| typedef void (*vac_error_callback_t)(void *, unsigned char *, int); |
| int vac_connect(char * name, char * chroot_prefix, vac_callback_t cb, |
| int rx_qlen); |
| int vac_disconnect(void); |
| int vac_read(char **data, int *l, unsigned short timeout); |
| int vac_write(char *data, int len); |
| void vac_free(void * msg); |
| |
| int vac_get_msg_index(unsigned char * name); |
| int vac_msg_table_size(void); |
| int vac_msg_table_max_index(void); |
| |
| void vac_rx_suspend (void); |
| void vac_rx_resume (void); |
| void vac_set_error_handler(vac_error_callback_t); |
| """) |
| |
| # Barfs on failure, no need to check success. |
| vpp_api = ffi.dlopen('libvppapiclient.so') |
| |
| |
| def vpp_atexit(self): |
| """Clean up VPP connection on shutdown.""" |
| if self.connected: |
| self.logger.debug('Cleaning up VPP on exit') |
| self.disconnect() |
| |
| vpp_object = None |
| |
| |
| def vpp_iterator(d): |
| if sys.version[0] == '2': |
| return d.iteritems() |
| else: |
| return d.items() |
| |
| |
| @ffi.callback("void(unsigned char *, int)") |
| def vac_callback_sync(data, len): |
| vpp_object.msg_handler_sync(ffi.buffer(data, len)) |
| |
| |
| @ffi.callback("void(unsigned char *, int)") |
| def vac_callback_async(data, len): |
| vpp_object.msg_handler_async(ffi.buffer(data, len)) |
| |
| |
| @ffi.callback("void(void *, unsigned char *, int)") |
| def vac_error_handler(arg, msg, msg_len): |
| vpp_object.logger.warning("VPP API client:: %s", ffi.string(msg, msg_len)) |
| |
| |
| class Empty(object): |
| pass |
| |
| |
| class FuncWrapper(object): |
| def __init__(self, func): |
| self._func = func |
| self.__name__ = func.__name__ |
| |
| def __call__(self, **kwargs): |
| return self._func(**kwargs) |
| |
| |
| 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, async_thread=True, |
| logger=logging.getLogger('vpp_papi'), loglevel='debug'): |
| """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. |
| """ |
| global vpp_object |
| vpp_object = self |
| self.logger = logger |
| logging.basicConfig(level=getattr(logging, loglevel.upper())) |
| |
| self.messages = {} |
| self.id_names = [] |
| self.id_msgdef = [] |
| self.buffersize = 10000 |
| self.connected = False |
| self.header = struct.Struct('>HI') |
| self.apifiles = [] |
| self.event_callback = None |
| self.message_queue = queue.Queue() |
| self.read_timeout = 0 |
| self.vpp_api = vpp_api |
| if async_thread: |
| self.event_thread = threading.Thread( |
| target=self.thread_msg_handler) |
| self.event_thread.daemon = True |
| self.event_thread.start() |
| |
| 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) |
| |
| # Register error handler |
| vpp_api.vac_set_error_handler(vac_error_handler) |
| |
| 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 vpp_iterator(msgdef['args']): |
| 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 vpp_iterator(msgdef['args']): |
| 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, typeonly=False): |
| 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 |
| idx = list(args.keys()).index(f[3]) - i |
| args[field_name].append(idx) |
| 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 |
| self.messages[name]['typeonly'] = typeonly |
| return self.messages[name] |
| |
| def add_type(self, name, typedef): |
| return self.add_message('vl_api_' + name + '_t', typedef, |
| typeonly=True) |
| |
| 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 |
| |
| @property |
| def api(self): |
| if not hasattr(self, "_api"): |
| raise Exception("Not connected, api definitions not available") |
| return self._api |
| |
| def _register_functions(self, async=False): |
| self.id_names = [None] * (self.vpp_dictionary_maxid + 1) |
| self.id_msgdef = [None] * (self.vpp_dictionary_maxid + 1) |
| self._api = Empty() |
| for name, msgdef in vpp_iterator(self.messages): |
| if self.messages[name]['typeonly']: |
| continue |
| crc = self.messages[name]['crc'] |
| n = name + '_' + crc[2:] |
| i = vpp_api.vac_get_msg_index(n.encode()) |
| if i > 0: |
| self.id_msgdef[i] = msgdef |
| self.id_names[i] = name |
| multipart = True if name.find('_dump') > 0 else False |
| f = self.make_function(name, i, msgdef, multipart, async) |
| setattr(self._api, name, FuncWrapper(f)) |
| |
| # old API stuff starts here - will be removed in 17.07 |
| if hasattr(self, name): |
| raise NameError( |
| 3, "Conflicting name in JSON definition: `%s'" % name) |
| setattr(self, name, f) |
| # old API stuff ends here |
| else: |
| self.logger.debug( |
| 'No such message type or failed CRC checksum: %s', n) |
| |
| def _write(self, buf): |
| """Send a binary-packed message to VPP.""" |
| if not self.connected: |
| raise IOError(1, 'Not connected') |
| return vpp_api.vac_write(ffi.from_buffer(buf), len(buf)) |
| |
| def _read(self): |
| if not self.connected: |
| raise IOError(1, 'Not connected') |
| mem = ffi.new("char **") |
| size = ffi.new("int *") |
| rv = vpp_api.vac_read(mem, size, self.read_timeout) |
| if rv: |
| raise IOError(rv, 'vac_read filed') |
| msg = bytes(ffi.buffer(mem[0], size[0])) |
| vpp_api.vac_free(mem[0]) |
| return msg |
| |
| def connect_internal(self, name, msg_handler, chroot_prefix, rx_qlen, |
| async): |
| pfx = chroot_prefix.encode() if chroot_prefix else ffi.NULL |
| rv = vpp_api.vac_connect(name.encode(), pfx, msg_handler, rx_qlen) |
| if rv != 0: |
| raise IOError(2, 'Connect failed') |
| self.connected = True |
| |
| self.vpp_dictionary_maxid = vpp_api.vac_msg_table_max_index() |
| self._register_functions(async=async) |
| |
| # Initialise control ping |
| crc = self.messages['control_ping']['crc'] |
| self.control_ping_index = vpp_api.vac_get_msg_index( |
| ('control_ping' + '_' + crc[2:]).encode()) |
| self.control_ping_msgdef = self.messages['control_ping'] |
| return rv |
| |
| 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 = vac_callback_sync if not async else vac_callback_async |
| return self.connect_internal(name, msg_handler, chroot_prefix, rx_qlen, |
| async) |
| |
| def connect_sync(self, name, chroot_prefix=None, rx_qlen=32): |
| """Attach to VPP in synchronous mode. Application must poll for events. |
| |
| name - the name of the client. |
| chroot_prefix - if VPP is chroot'ed, the prefix of the jail |
| rx_qlen - the length of the VPP message receive queue between |
| client and server. |
| """ |
| |
| return self.connect_internal(name, ffi.NULL, chroot_prefix, rx_qlen, |
| async=False) |
| |
| def disconnect(self): |
| """Detach from VPP.""" |
| rv = vpp_api.vac_disconnect() |
| self.connected = False |
| return rv |
| |
| 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 |
| self.message_queue.put_nowait(r) |
| else: |
| raise IOError(2, 'RPC reply message received in event handler') |
| |
| def decode_incoming_msg(self, msg): |
| if not msg: |
| self.logger.warning('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. |
| """ |
| |
| if 'context' not in kwargs: |
| context = self.get_context() |
| kwargs['context'] = context |
| else: |
| context = kwargs['context'] |
| kwargs['_vl_msg_id'] = i |
| b = self.encode(msgdef, kwargs) |
| |
| vpp_api.vac_rx_suspend() |
| self._write(b) |
| |
| 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. |
| rl = [] |
| while (True): |
| msg = self._read() |
| if not msg: |
| raise IOError(2, 'VPP API client: read failed') |
| |
| r = self.decode_incoming_msg(msg) |
| msgname = type(r).__name__ |
| if context not in r or r.context == 0 or context != r.context: |
| self.message_queue.put_nowait(r) |
| continue |
| |
| if not multipart: |
| rl = r |
| break |
| if msgname == 'control_ping_reply': |
| break |
| |
| rl.append(r) |
| |
| vpp_api.vac_rx_resume() |
| |
| return rl |
| |
| 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 'context' not 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 |
| |
| def thread_msg_handler(self): |
| """Python thread calling the user registerd message handler. |
| |
| This is to emulate the old style event callback scheme. Modern |
| clients should provide their own thread to poll the event |
| queue. |
| """ |
| while True: |
| r = self.message_queue.get() |
| msgname = type(r).__name__ |
| if self.event_callback: |
| self.event_callback(msgname, r) |