#!/usr/bin/python import sys, struct, logging from ippattributegroup import AttributeGroup from ippattribute import Attribute from ippvalue import Value # initialize logger logger = logging.getLogger("ippLogger") class Request(): """ From RFC 2565: The encoding for an operation request or response consists of: ----------------------------------------------- | version-number | 2 bytes - required ----------------------------------------------- | operation-id (request) | | or | 2 bytes - required | status-code (response) | ----------------------------------------------- | request-id | 4 bytes - required ----------------------------------------------------------- | xxx-attributes-tag | 1 byte | ----------------------------------------------- |-0 or more | xxx-attribute-sequence | n bytes | ----------------------------------------------------------- | end-of-attributes-tag | 1 byte - required ----------------------------------------------- | data | q bytes - optional ----------------------------------------------- """ # either give the version, operation_id, request_id, # attribute_sequence, and data, or a file handler (request) which # can be read from to get the request def __init__(self, version=None, operation_id=None, request_id=None, attribute_groups=[], data=None, request=None, length=sys.maxint): """ Create a Request. Takes either the segments of the request separately, or a file handle for the request to parse. If the file handle is passed in, all other arguments are ignored. Keyword arguments for passing in the segments of the request: version -- a tuple of two signed chars, identifying the major version and minor version numbers of the request operation_id -- a signed short, identifying the id of the requested operation request_id -- a signed int, identifying the id of the request itself. attribute_groups -- a list of Attributes, at least length 1 data -- (optional) variable length, containing the actual data of the request Keyword arguments for passing in the raw request: request -- a file handle that supports the read() operation """ if request is None: # make sure the version number isn't empty assert version is not None # make sure verison is a tuple of length 2 assert isinstance(version, tuple) assert len(version) == 2 # make sure the operation id isn't empty assert operation_id is not None # make sure the request id isn't empty assert request_id is not None # make sure attribute_groups is a list of Attributes assert len(attribute_groups) > 0 for a in attribute_groups: assert isinstance(a, AttributeGroup) # if the request isn't None, then we'll read directly from # that file handle if request is not None: # read the version-number (two signed chars) self.version = struct.unpack('>bb', request.read(2)) length -= 2 logger.debug("version-number : (0x%X, 0x%X)" % self.version) # read the operation-id (or status-code, but that's only # for a response) (signed short) self.operation_id = struct.unpack('>h', request.read(2))[0] length -= 2 logger.debug("operation-id : 0x%X" % self.operation_id) # read the request-id (signed int) self.request_id = struct.unpack('>i', request.read(4))[0] length -= 4 logger.debug("request-id : 0x%X" % self.request_id) # now we have to read in the attributes. Each attribute # has a tag (1 byte) and a sequence of values (n bytes) self.attribute_groups = [] # read in the next byte next_byte = struct.unpack('>b', request.read(1))[0] length -=1 logger.debug("next byte : 0x%X" % next_byte) # as long as the next byte isn't signaling the end of the # attributes, keep looping and parsing attributes while next_byte != AttributeTags.END: attribute_group_tag = next_byte logger.debug("attribute-tag : %i" % attribute_group_tag) attributes = [] next_byte = struct.unpack('>b', request.read(1))[0] length -= 1 logger.debug("next byte : 0x%X" % next_byte) while next_byte > 0x0F: # read in the value tag (signed char) value_tag = next_byte logger.debug("value-tag : 0x%X" % value_tag) # read in the length of the name (signed short) name_length = struct.unpack('>h', request.read(2))[0] length -= 2 logger.debug("name-length : %i" % name_length) if name_length != AttributeTags.ZERO_NAME_LENGTH: # read the name (a string of name_length bytes) name = request.read(name_length) length -= name_length logger.debug("name : %s" % name) # read in the length of the value (signed short) value_length = struct.unpack('>h', request.read(2))[0] length -= 2 logger.debug("value-length : %i" % value_length) # read in the value (string of value_length bytes) value = request.read(value_length) length -= value_length ippvalue = Value(value_tag, value) logger.debug("value : %s" % ippvalue.value) # create a new Attribute from the data we just # read in, and add it to our attributes list attributes.append(Attribute(name, [ippvalue])) else: # read in the length of the value (signed short) value_length = struct.unpack('>h', request.read(2))[0] length -= 2 logger.debug("value-length : %i" % value_length) # read in the value (string of value_length bytes) value = request.read(value_length) length -= value_length ippvalue = Value(value_tag, value) logger.debug("value : %s" % ippvalue.value) # add another value to the last attribute attributes[-1].values.append(ippvalue) # read another byte next_byte = struct.unpack('>b', request.read(1))[0] length -= 1 self.attribute_groups.append(AttributeGroup( attribute_group_tag, attributes)) # once we hit the end-of-attributes tag, the only thing # left is the data, so go ahead and read all of it assert length >= 0 self.data = request.read(length) logger.debug("data : %s" % self.data) # otherwise, just set the class variables to the keyword # arguments passed in else: self.version = (version[0], version[1]) self.operation_id = operation_id self.request_id = request_id self.attribute_groups = attribute_groups self.data = data def getAttributeGroup(self, tag): return filter(lambda x: x.attribute_group_tag == tag, self.attribute_groups) def toBinaryData(self): """ Packs the value data into binary data. """ # convert the version, operation id, and request id to binary preattributes = struct.pack('>bbhi', self.version[0], self.version[1], self.operation_id, self.request_id) # convert the attribute groups to binary attribute_groups = ''.join([a.toBinaryData() for a in self.attribute_groups]) # conver the end-of-attributes-tag to binary end_of_attributes_tag = struct.pack('>b', AttributeTags.END) # convert the data to binary if self.data is not None: data = ''.join([struct.pack('>b', x) for x in self.data]) else: data = '' # append everything together and return it return preattributes + attribute_groups + end_of_attributes_tag + data