| #!/usr/bin/python |
| # |
| # This python script generates wrapper functions for OpenFlow messages |
| # |
| # See the doc string below for more info |
| # |
| |
| # To do: |
| # Default type values for messages |
| # Generate all message objects |
| # Action list objects? |
| # Autogen lengths when possible |
| # Dictionaries for enum strings |
| # Resolve sub struct initializers (see ofp_flow_mod) |
| |
| |
| """ |
| Generate wrapper classes for OpenFlow messages |
| |
| (C) Copyright Stanford University |
| Date February 2010 |
| Created by dtalayco |
| |
| Attempting to follow http://www.python.org/dev/peps/pep-0008/ |
| The main exception is that our class names do not use CamelCase |
| so as to more closely match the original C code names. |
| |
| This file is meant to generate a file of_wrapper.py which imports |
| the base classes generated form automatic processing of openflow.h |
| and produces wrapper classes for each OpenFlow message type. |
| |
| This file will normally be included in of_message.py which provides |
| additional hand-generated work. |
| |
| There are two types of structures/classes here: base components and |
| message classes. |
| |
| Base components are the base data classes which are fixed |
| length structures including: |
| ofp_header |
| Each ofp_action structure |
| ofp_phy_port |
| The array elements of all the stats reply messages |
| The base components are to be imported from a file of_header.py. |
| |
| Message classes define a complete message on the wire. These are |
| comprised of possibly variable length lists of possibly variably |
| typed objects from the base component list above. |
| |
| Each OpenFlow message has a header and zero or more fixed length |
| members (the "core members" of the class) followed by zero or more |
| variable length lists. |
| |
| The wrapper classes should live in their own name space, probably |
| of_message. Automatically generated base component and skeletons for |
| the message classes are assumed generated and the wrapper classes |
| will inherit from those. |
| |
| Every message class must implement pack and unpack functions to |
| convert between the class and a string representing what goes on the |
| wire. |
| |
| For unpacking, the low level (base-component) classes must implement |
| their own unpack functions. A single top level unpack function |
| will do the parsing and call the lower layer unpack functions as |
| appropriate. |
| |
| Every base and message class should implement a show function to |
| (recursively) display the contents of the object. |
| |
| Certain OpenFlow message types are further subclassed. These include |
| stats_request, stats_reply and error. |
| |
| """ |
| |
| # Don't generate header object in messages |
| # Map each message to a body that doesn't include the header |
| # The body has does not include variable length info at the end |
| |
| import re |
| import string |
| import sys |
| |
| message_top_matter = """ |
| # Python OpenFlow message wrapper classes |
| |
| from ofp import * |
| from action_list import action_list |
| |
| # This will never happen; done to avoid lint warning |
| if __name__ == '__main__': |
| def of_message_parse(msg): return None |
| |
| # Define templates for documentation |
| class ofp_template_msg: |
| \""" |
| Sample base class for template_msg; normally auto generated |
| This class should live in the of_header name space and provides the |
| base class for this type of message. It will be wrapped for the |
| high level API. |
| |
| \""" |
| def __init__(self): |
| \""" |
| Constructor for base class |
| |
| \""" |
| self.header = ofp_header() |
| # Additional base data members declared here |
| # Normally will define pack, unpack, __len__ functions |
| |
| class template_msg(ofp_template_msg): |
| \""" |
| Sample class wrapper for template_msg |
| This class should live in the of_message name space and provides the |
| high level API for an OpenFlow message object. These objects must |
| implement the functions indicated in this template. |
| |
| \""" |
| def __init__(self): |
| \""" |
| Constructor |
| Must set the header type value appropriately for the message |
| |
| \""" |
| ofp_template_msg.__init__(self) |
| # For a real message, will be set to an integer |
| self.header.type = "TEMPLATE_MSG_VALUE" |
| def pack(self): |
| \""" |
| Pack object into string |
| |
| @return The packed string which can go on the wire |
| |
| \""" |
| pass |
| def unpack(self, binary_string): |
| \""" |
| Unpack object from a binary string |
| |
| @param binary_string The wire protocol byte string holding the object |
| represented as an array of bytes. |
| |
| @return Typically returns the remainder of binary_string that |
| was not parsed. May give a warning if that string is non-empty |
| |
| \""" |
| pass |
| def __len__(self): |
| \""" |
| Return the length of this object once packed into a string |
| |
| @return An integer representing the number bytes in the packed |
| string. |
| |
| \""" |
| pass |
| def show(self, prefix=''): |
| \""" |
| Display the contents of the object in a readable manner |
| |
| @param prefix Printed at the beginning of each line. |
| |
| \""" |
| pass |
| def __eq__(self, other): |
| \""" |
| Return True if self and other hold the same data |
| |
| @param other Other object in comparison |
| |
| \""" |
| pass |
| def __ne__(self, other): |
| \""" |
| Return True if self and other do not hold the same data |
| |
| @param other Other object in comparison |
| |
| \""" |
| pass |
| """ |
| |
| # Dictionary mapping wrapped classes to the auto-generated structure |
| # underlieing the class (body only, not header or var-length data) |
| message_class_map = { |
| "hello" : "ofp_header", |
| "error" : "ofp_error_msg", |
| "echo_request" : "ofp_header", |
| "echo_reply" : "ofp_header", |
| "vendor" : "ofp_vendor_header", |
| "features_request" : "ofp_header", |
| "features_reply" : "ofp_switch_features", |
| "get_config_request" : "ofp_header", |
| "get_config_reply" : "ofp_switch_config", |
| "set_config" : "ofp_switch_config", |
| "packet_in" : "ofp_packet_in", |
| "flow_removed" : "ofp_flow_removed", |
| "port_status" : "ofp_port_status", |
| "packet_out" : "ofp_packet_out", |
| "flow_mod" : "ofp_flow_mod", |
| "port_mod" : "ofp_port_mod", |
| "stats_request" : "ofp_stats_request", |
| "stats_reply" : "ofp_stats_reply", |
| "barrier_request" : "ofp_header", |
| "barrier_reply" : "ofp_header", |
| "queue_get_config_request" : "ofp_queue_get_config_request", |
| "queue_get_config_reply" : "ofp_queue_get_config_reply" |
| } |
| |
| # These messages have a string member at the end of the data |
| string_members = [ |
| "hello", |
| "error", |
| "echo_request", |
| "echo_reply", |
| "vendor", |
| "packet_in", |
| "packet_out" |
| ] |
| |
| # These messages have a list (with the given name) in the data, |
| # after the core members; the type is given for validation |
| list_members = { |
| "features_reply" : ('ports', None), |
| "packet_out" : ('actions', 'action_list'), |
| "flow_mod" : ('actions', 'action_list'), |
| "queue_get_config_reply" : ('queues', None) |
| } |
| |
| _ind = " " |
| |
| def _p1(s): print _ind + s |
| def _p2(s): print _ind * 2 + s |
| def _p3(s): print _ind * 3 + s |
| def _p4(s): print _ind * 4 + s |
| |
| # Okay, this gets kind of ugly: |
| # There are three variables: |
| # has_core_members: If parent class is not ofp_header, has inheritance |
| # has_list: Whether class has trailing array or class |
| # has_string: Whether class has trailing string |
| |
| def gen_message_wrapper(msg): |
| """ |
| Generate a wrapper for the given message based on above info |
| @param msg String identifying the message name for the class |
| """ |
| |
| msg_name = "OFPT_" + msg.upper() |
| parent = message_class_map[msg] |
| |
| has_list = False # Has trailing list |
| has_core_members = False |
| has_string = False # Has trailing string |
| if parent != 'ofp_header': |
| has_core_members = True |
| if msg in list_members.keys(): |
| (list_var, list_type) = list_members[msg] |
| has_list = True |
| if msg in string_members: |
| has_string = True |
| |
| if has_core_members: |
| print "class " + msg + "(" + parent + "):" |
| else: |
| print "class " + msg + ":" |
| _p1('"""') |
| _p1("Wrapper class for " + msg) |
| print |
| if has_list: |
| if list_type == None: |
| _p1("Has trailing variable array " + list_var); |
| else: |
| _p1("Has trailing object " + list_var + " of type " + list_type); |
| print |
| if has_string: |
| _p1("Has trailing string data") |
| print |
| _p1('"""') |
| |
| print |
| _p1("def __init__(self):") |
| if has_core_members: |
| _p2(parent + ".__init__(self)") |
| _p2("self.header = ofp_header()") |
| _p2("self.header.type = " + msg_name) |
| if has_list: |
| if list_type == None: |
| _p2('self.' + list_var + ' = []') |
| else: |
| _p2('self.' + list_var + ' = ' + list_type + '()') |
| if has_string: |
| _p2('self.data = ""') |
| |
| print |
| _p1("def pack(self):") |
| _p2("# Fixme: Calculate length for header, etc, once __len__ fixed") |
| _p2("packed = self.header.pack()") |
| if has_core_members: |
| _p2("packed += " + parent + ".pack()") |
| if has_list: |
| if list_type == None: |
| _p2('for obj in self.' + list_var + ':') |
| _p3('packed += obj.pack()') |
| else: |
| _p2('packed += self.' + list_var + '.pack()') |
| if has_string: |
| _p2('packed += self.data') |
| |
| print |
| _p1("def unpack(self, binary_string):") |
| _p2("binary_string = self.header.unpack(binary_string)") |
| if has_core_members: |
| _p2("binary_string = " + parent + ".unpack(self, binary_string)") |
| if has_list: |
| if list_type == None: |
| _p2("for obj in self." + list_var + ":") |
| _p3("binary_string = obj.unpack(binary_string)") |
| elif msg == "packet_out": # Special case this |
| _p2('binary_string = self.actions.unpack(bytes=self.actions_len)') |
| elif msg == "flow_mod": # Special case this |
| _p2("ai_len = self.header.length - OFP_FLOW_MOD_BYTES") |
| _p2("binary_string = self.actions.unpack(bytes=ai_len)") |
| else: |
| _p2("binary_string = self." + list_var + ".unpack(binary_string)") |
| if has_string: |
| _p2("self.data = binary_string") |
| _p2("binary_string = ''") |
| else: |
| _p2("# Fixme: If no self.data, add check for data remaining") |
| _p2("return binary_string") |
| |
| print |
| _p1("def __len__(self):") |
| _p2("# Fixme: Do the right thing") |
| _p2("return len(self.pack())") |
| |
| print |
| _p1("def show(self, prefix=''):") |
| _p2("print prefix + '" + msg + " (" + msg_name + ")'") |
| _p2("prefix += ' '") |
| _p2("self.header.show(prefix)") |
| if has_core_members: |
| _p2(parent + ".show(self, prefix)") |
| if has_list: |
| if list_type == None: |
| _p2('print prefix + "Array ' + list_var + '"') |
| _p2('for obj in self.' + list_var +':') |
| _p3("obj.show(prefix + ' ')") |
| else: |
| _p2('print prefix + "List ' + list_var + '"') |
| _p2('self.' + list_var + ".show(prefix + ' ')") |
| if has_string: |
| _p2("print prefix + 'data is of length ' + str(len(self.data))") |
| _p2("if len(self.data) > 0:") |
| _p3("obj = of_message_parse(self.data)") |
| _p3("if obj != None:") |
| _p4("obj.show(prefix)") |
| _p3("else:") |
| _p4('print prefix + "Unable to parse data"') |
| |
| print |
| _p1("def __eq__(self, other):") |
| _p2("if type(self) != type (other): return False") |
| _p2("if self.header.__ne__(other.header): return False") |
| if has_core_members: |
| _p2("if " + parent + ".__ne__(other." + parent + "): return False") |
| if has_string: |
| _p2("if self.data != other.data: return False") |
| if has_list: |
| _p2("if self." + list_var + " != other." + list_var + ": return False") |
| _p2("return True") |
| |
| print |
| _p1("def __ne__(self, other): return not self.__eq__(other)") |
| |
| |
| |
| ################################################################ |
| # |
| # Stats request subclasses |
| # description_request, flow, aggregate, table, port, vendor |
| # |
| ################################################################ |
| |
| # table and desc stats requests are special with empty body |
| extra_ofp_stats_req_defs = """ |
| # Stats request bodies for desc and table stats are not defined in the |
| # OpenFlow header; We define them here. They are empty classes, really |
| |
| class ofp_desc_stats_request: |
| \""" |
| Forced definition of ofp_desc_stats_request (empty class) |
| \""" |
| def __init__(self): |
| pass |
| def pack(self, assertstruct=True): |
| return "" |
| def unpack(self, binary_string): |
| return binary_string |
| def __len__(self): |
| return 0 |
| def show(self, prefix=''): |
| pass |
| def __eq__(self, other): |
| return type(self) == type(other) |
| def __ne__(self, other): |
| return type(self) != type(other) |
| |
| OFP_DESC_STATS_REQUEST_BYTES = 0 |
| |
| class ofp_table_stats_request: |
| \""" |
| Forced definition of ofp_table_stats_request (empty class) |
| \""" |
| def __init__(self): |
| pass |
| def pack(self, assertstruct=True): |
| return "" |
| def unpack(self, binary_string): |
| return binary_string |
| def __len__(self): |
| return 0 |
| def show(self, prefix=''): |
| pass |
| def __eq__(self, other): |
| return type(self) == type(other) |
| def __ne__(self, other): |
| return type(self) != type(other) |
| |
| OFP_TABLE_STATS_REQUEST_BYTES = 0 |
| |
| """ |
| |
| stats_request_template = """ |
| class --TYPE--_stats_request(ofp_stats_request, ofp_--TYPE--_stats_request): |
| \""" |
| Wrapper class for --TYPE-- stats request message |
| \""" |
| def __init__(self): |
| self.header = ofp_header() |
| ofp_stats_request.__init__(self) |
| ofp_--TYPE--_stats_request.__init__(self) |
| self.header.type = OFPT_STATS_REQUEST |
| self.type = --STATS_NAME-- |
| |
| def pack(self, assertstruct=True): |
| packed = ofp_stats_request.pack(self) |
| packed += ofp_--TYPE--_stats_request.pack(self) |
| |
| def unpack(self, binary_string): |
| binary_string = ofp_stats_request.unpack(self, binary_string) |
| binary_string = ofp_--TYPE--_stats_request.unpack(self, binary_string) |
| if len(binary_string) != 0: |
| print "Error unpacking --TYPE--: extra data" |
| return binary_string |
| |
| def __len__(self): |
| return len(self.header) + OFP_STATS_REQUEST_BYTES + \\ |
| OFP_--TYPE_UPPER--_STATS_REQUEST_BYTES |
| |
| def show(self, prefix=''): |
| print prefix + "--TYPE--_stats_request" |
| ofp_stats_request.show(self) |
| ofp_--TYPE--_stats_request.show(self) |
| |
| def __eq__(self, other): |
| return (ofp_stats_request.__eq__(self, other) and |
| ofp_--TYPE--_stats_request.__eq__(self, other)) |
| |
| def __ne__(self, other): return not self.__eq__(other) |
| """ |
| |
| ################################################################ |
| # |
| # Stats replies always have an array at the end. |
| # For aggregate and desc, these arrays are always of length 1 |
| # This array is always called stats |
| # |
| ################################################################ |
| |
| |
| # Template for objects stats reply messages |
| stats_reply_template = """ |
| class --TYPE--_stats_reply(ofp_stats_reply): |
| \""" |
| Wrapper class for --TYPE-- stats reply |
| \""" |
| def __init__(self): |
| self.header = ofp_header() |
| ofp_stats_reply.__init__(self) |
| self.header.type = OFPT_STATS_REPLY |
| self.type = --STATS_NAME-- |
| # stats: Array of type --TYPE--_stats_entry |
| self.stats = [] |
| |
| def pack(self, assertstruct=True): |
| packed = ofp_stats_reply.pack(self) |
| for obj in self.stats: |
| packed += obj.pack() |
| |
| def unpack(self, binary_string): |
| binary_string = ofp_stats_reply.unpack(self, binary_string) |
| dummy = --TYPE--_stats_entry() |
| while len(binary_string) >= len(dummy): |
| obj = --TYPE--_stats_entry() |
| binary_string = obj.unpack(binary_string) |
| self.stats.append(obj) |
| if len(binary_string) != 0: |
| print "ERROR unpacking --TYPE-- stats string: extra bytes" |
| return binary_string |
| |
| def __len__(self): |
| length = len(self.header) + OFP_STATS_REPLY_BYTES |
| for obj in self.stats: |
| length += len(obj) |
| return length |
| |
| def show(self, prefix=''): |
| print prefix + "--TYPE--_stats_reply" |
| ofp_stats_reply.show(self) |
| for obj in self.stats: |
| obj.show() |
| |
| def __eq__(self, other): |
| if ofp_stats_reply.__ne__(self, other): return False |
| return self.stats == other.stats |
| |
| def __ne__(self, other): return not self.__eq__(other) |
| """ |
| |
| # |
| # To address variations in stats reply bodies, the following |
| # "_entry" classes are defined for each element in the reply |
| # |
| |
| extra_stats_entry_defs = """ |
| # Stats entries define the content of one element in a stats |
| # reply for the indicated type; define _entry for consistency |
| |
| aggregate_stats_entry = ofp_aggregate_stats_reply |
| desc_stats_entry = ofp_desc_stats |
| port_stats_entry = ofp_port_stats |
| queue_stats_entry = ofp_queue_stats |
| table_stats_entry = ofp_table_stats |
| """ |
| |
| # Special case flow_stats to handle actions_list |
| |
| flow_stats_entry_def = """ |
| # |
| # Flow stats entry contains an action list of variable length, so |
| # it is done by hand |
| # |
| |
| class flow_stats_entry(ofp_flow_stats): |
| \""" |
| Special case flow stats entry to handle action list object |
| \""" |
| def __init__(self): |
| ofp_flow_stats.__init__(self) |
| self.actions = action_list() |
| |
| def pack(self, assertstruct=True): |
| if self.length < OFP_FLOW_STATS_BYTES: |
| print "ERROR in flow_stats_entry pack: length member is too small" |
| return None |
| packed = ofp_flow_stats.pack(self, assertstruct) |
| packed += self.actions.pack() |
| return packed |
| |
| def unpack(self, binary_string): |
| binary_string = ofp_flow_stats.unpack(self, binary_string) |
| ai_len = self.length - OFP_FLOW_STATS_BYTES |
| binary_string = self.actions.unpack(binary_string, bytes=ai_len) |
| return binary_string |
| |
| def __len__(self): |
| return OFP_FLOW_STATS_BYTES + len(self.actions) |
| |
| def show(self, prefix=''): |
| print prefix + "flow_stats_entry" |
| ofp_flow_stats.show(self, prefix + ' ') |
| self.actions.show(prefix + ' ') |
| |
| def __eq__(self, other): |
| return (ofp_flow_stats.__eq__(self, other) and |
| self.actions == other.actions) |
| |
| def __ne__(self, other): return not self.__eq__(other) |
| """ |
| |
| stats_types = [ |
| 'aggregate', |
| 'desc', |
| 'flow', |
| 'port', |
| 'queue', |
| 'table'] |
| |
| if __name__ == '__main__': |
| |
| print message_top_matter |
| |
| print """ |
| ################################################################ |
| # |
| # OpenFlow Message Definitions |
| # |
| ################################################################ |
| """ |
| |
| msg_types = message_class_map.keys() |
| msg_types.sort() |
| |
| for t in msg_types: |
| gen_message_wrapper(t) |
| print |
| |
| print """ |
| ################################################################ |
| # |
| # Stats request and reply subclass definitions |
| # |
| ################################################################ |
| """ |
| |
| print extra_ofp_stats_req_defs |
| print extra_stats_entry_defs |
| print flow_stats_entry_def |
| |
| # Generate stats request and reply subclasses |
| for t in stats_types: |
| stats_name = "OFPST_" + t.upper() |
| to_print = re.sub('--TYPE--', t, stats_request_template) |
| to_print = re.sub('--TYPE_UPPER--', t.upper(), to_print) |
| to_print = re.sub('--STATS_NAME--', stats_name, to_print) |
| print to_print |
| to_print = re.sub('--TYPE--', t, stats_reply_template) |
| to_print = re.sub('--STATS_NAME--', stats_name, to_print) |
| print to_print |
| |
| |
| # |
| # OFP match variants |
| # ICMP 0x801 (?) ==> icmp_type/code replace tp_src/dst |
| # |
| |
| |