| 1 | #!/usr/bin/python |
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| 2 | |
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| 3 | import sys |
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| 4 | |
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| 5 | # various tags |
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| 6 | zero_name_length = 0x00 |
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| 7 | operation_attributes_tag = 0x01 |
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| 8 | job_attributes_tag = 0x02 |
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| 9 | end_of_attributes_tag = 0x03 |
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| 10 | printer_attributes_tag = 0x04 |
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| 11 | unsupported_attributes_tag = 0x05 |
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| 12 | |
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| 13 | # "out of band" value tags |
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| 14 | oob_unsupported_value_tag = 0x10 |
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| 15 | oob_default_value_tag = 0x11 |
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| 16 | oob_unknown_value_tag = 0x12 |
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| 17 | oob_no_value_tag = 0x13 |
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| 18 | |
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| 19 | # integer value tags |
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| 20 | generic_integer_value_tag = 0x20 |
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| 21 | integer_value_tag = 0x21 |
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| 22 | boolean_value_tag = 0x22 |
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| 23 | enum_value_tag = 0x23 |
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| 24 | |
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| 25 | # octetString value tags |
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| 26 | unspecified_octetString_value_tag = 0x30 |
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| 27 | dateTime_value_tag = 0x31 |
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| 28 | resolution_value_tag = 0x32 |
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| 29 | rangeOfInteger_value_tag = 0x33 |
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| 30 | collection_value_tag = 0x34 |
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| 31 | textWithLanguage_value_tag = 0x35 |
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| 32 | nameWithLanguage_value_tag = 0x36 |
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| 33 | |
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| 34 | # character-string value tags |
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| 35 | generic_char_string_value_tag = 0x40 |
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| 36 | textWithoutLanguage_value_tag = 0x41 |
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| 37 | nameWithoutLanguage_value_tag = 0x42 |
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| 38 | keyword_value_tag = 0x44 |
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| 39 | uri_value_tag = 0x45 |
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| 40 | uriScheme_value_tag = 0x46 |
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| 41 | charset_value_tag = 0x47 |
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| 42 | naturalLanguage_value_tag = 0x48 |
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| 43 | mimeMediaType_value_tag = 0x49 |
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| 44 | |
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| 45 | class IPPValue(): |
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| 46 | """ |
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| 47 | An IPP value consists of a tag and a value, and optionally, a name. |
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| 48 | """ |
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| 49 | |
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| 50 | def __init__(self, value_tag, name, value): |
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| 51 | """ |
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| 52 | Initialize an IPPValue: |
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| 53 | |
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| 54 | Arguments: |
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| 55 | |
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| 56 | value_tag -- one byte, identifying the type of value |
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| 57 | |
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| 58 | name -- (optional) variable size, identifying the name of |
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| 59 | this value |
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| 60 | |
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| 61 | value -- variable size, containing the actual value |
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| 62 | """ |
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| 63 | |
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| 64 | # make sure value_tag isn't empty |
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| 65 | assert value_tag is not None |
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| 66 | # make sure the size of value_tag is one byte |
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| 67 | assert sys.getsizeof(value_tag) == 1 |
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| 68 | # make sure value isn't empty |
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| 69 | assert value is not None |
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| 70 | |
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| 71 | self.value_tag = value_tag |
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| 72 | self.name = name |
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| 73 | self.value = value |
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| 74 | |
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| 75 | class IPPAttribute(): |
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| 76 | """ |
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| 77 | From RFC 2565: |
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| 78 | |
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| 79 | Each attribute consists of: |
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| 80 | ----------------------------------------------- |
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| 81 | | value-tag | 1 byte |
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| 82 | ----------------------------------------------- |
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| 83 | | name-length (value is u) | 2 bytes |
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| 84 | ----------------------------------------------- |
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| 85 | | name | u bytes |
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| 86 | ----------------------------------------------- |
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| 87 | | value-length (value is v) | 2 bytes |
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| 88 | ----------------------------------------------- |
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| 89 | | value | v bytes |
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| 90 | ----------------------------------------------- |
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| 91 | |
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| 92 | An additional value consists of: |
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| 93 | ----------------------------------------------------------- |
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| 94 | | value-tag | 1 byte | |
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| 95 | ----------------------------------------------- | |
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| 96 | | name-length (value is 0x0000) | 2 bytes | |
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| 97 | ----------------------------------------------- |-0 or more |
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| 98 | | value-length (value is w) | 2 bytes | |
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| 99 | ----------------------------------------------- | |
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| 100 | | value | w bytes | |
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| 101 | ----------------------------------------------------------- |
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| 102 | """ |
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| 103 | |
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| 104 | def __init__(self, attribute_tag, values): |
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| 105 | """ |
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| 106 | Initialize an IPPAttribute. |
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| 107 | |
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| 108 | Arguments: |
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| 109 | |
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| 110 | attribute_tag -- one byte, identifying the type of attribute |
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| 111 | |
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| 112 | values -- a list of IPPValues. May not be empty. |
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| 113 | """ |
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| 114 | |
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| 115 | # make sure attribute_tag isn't empty |
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| 116 | assert attribute_tag is not None |
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| 117 | # make sure attribute_tag is of the right size |
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| 118 | assert sys.getsizeof(attribute_tag) == 1 |
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| 119 | |
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| 120 | # make sure the list of values isn't empty |
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| 121 | assert len(values) > 0 |
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| 122 | # make sure each value is an IPPValue |
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| 123 | for value in values: assert isinstance(value, IPPValue) |
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| 124 | |
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| 125 | self.attribute_tag = attribute_tag |
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| 126 | self.values = values |
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| 127 | |
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| 128 | class IPPRequest(): |
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| 129 | """ |
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| 130 | From RFC 2565: |
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| 131 | |
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| 132 | The encoding for an operation request or response consists of: |
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| 133 | ----------------------------------------------- |
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| 134 | | version-number | 2 bytes - required |
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| 135 | ----------------------------------------------- |
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| 136 | | operation-id (request) | |
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| 137 | | or | 2 bytes - required |
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| 138 | | status-code (response) | |
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| 139 | ----------------------------------------------- |
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| 140 | | request-id | 4 bytes - required |
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| 141 | ----------------------------------------------------------- |
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| 142 | | xxx-attributes-tag | 1 byte | |
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| 143 | ----------------------------------------------- |-0 or more |
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| 144 | | xxx-attribute-sequence | n bytes | |
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| 145 | ----------------------------------------------------------- |
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| 146 | | end-of-attributes-tag | 1 byte - required |
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| 147 | ----------------------------------------------- |
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| 148 | | data | q bytes - optional |
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| 149 | ----------------------------------------------- |
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| 150 | """ |
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| 151 | |
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| 152 | # either give the version, operation_id, request_id, |
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| 153 | # attribute_sequence, and data, or a file handler (request) which |
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| 154 | # can be read from to get the request |
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| 155 | def __init__(self, version=None, operation_id=None, request_id=None, attributes=[], data=None, request=None): |
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| 156 | """ |
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| 157 | Create an IPPRequest. Takes either the segments of the |
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| 158 | request separately, or a file handle for the request to parse. |
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| 159 | If the file handle is passed in, all other arguments are |
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| 160 | ignored. |
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| 161 | |
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| 162 | Keyword arguments for passing in the segments of the request: |
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| 163 | |
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| 164 | version -- two bytes, identifying the version number of |
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| 165 | the request |
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| 166 | |
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| 167 | operation_id -- two bytes, identifying the id of the |
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| 168 | requested operation |
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| 169 | |
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| 170 | request_id -- four bytes, identifying the id of the |
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| 171 | request itself. |
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| 172 | |
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| 173 | attributes -- a list of IPPAttributes. May be empty. |
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| 174 | |
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| 175 | data -- (optional) variable length, containing the actual |
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| 176 | data of the request |
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| 177 | |
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| 178 | Keyword arguments for passing in the raw request: |
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| 179 | |
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| 180 | request -- a file handle that supports the read() |
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| 181 | operation |
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| 182 | """ |
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| 183 | |
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| 184 | if request is None: |
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| 185 | # make sure the version number isn't empty |
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| 186 | assert version is not None |
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| 187 | # make sure the version number is two bytes long |
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| 188 | assert sys.getsizeof(version) == 2 |
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| 189 | # make sure the operation id isn't empty |
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| 190 | assert operation_id is not None |
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| 191 | # make sure the operation id is two bytes long |
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| 192 | assert sys.getsizeof(operation_id) == 2 |
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| 193 | # make sure the request id isn't empty |
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| 194 | assert request_id is not None |
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| 195 | # make sure the request id is four bytes long |
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| 196 | assert sys.getsizeof(request_id) == 4 |
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| 197 | |
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| 198 | # if the request isn't None, then we'll read directly from |
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| 199 | # that file handle |
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| 200 | if request is not None: |
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| 201 | # read the version-number (two bytes) |
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| 202 | self.version = request.read(2) |
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| 203 | |
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| 204 | # read the operation-id (or status-code, but that's only |
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| 205 | # for a response) (two bytes) |
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| 206 | self.operation_id = request.read(2) |
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| 207 | |
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| 208 | # read the request-id (4 bytes) |
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| 209 | self.request_id = request.read(4) |
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| 210 | |
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| 211 | # now we have to read in the attributes. Each attribute |
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| 212 | # has a tag (1 byte) and a sequence of values (n bytes) |
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| 213 | self.attributes = [] |
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| 214 | |
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| 215 | # read in the next byte |
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| 216 | next_byte = request.read(1) |
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| 217 | |
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| 218 | # as long as the next byte isn't signaling the end of the |
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| 219 | # attributes, keep looping and parsing attributes |
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| 220 | while next_byte != end_of_attributes_tag: |
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| 221 | |
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| 222 | # if the next byte is an attribute tag, then we're at |
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| 223 | # the start of a new attribute |
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| 224 | if next_byte <= 0x0F: |
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| 225 | |
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| 226 | attribute_tag = next_byte |
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| 227 | # read in the value tag (one byte) |
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| 228 | value_tag = request.read(1) |
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| 229 | # read in the length of the name (two bytes) |
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| 230 | name_length = request.read(2) |
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| 231 | # read the name (name_length bytes) |
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| 232 | name = request.read(name_length) |
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| 233 | # read in the length of the value (two bytes) |
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| 234 | value_length = request.read(2) |
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| 235 | # read in the value (value_length bytes) |
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| 236 | value = request.read(value_length) |
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| 237 | |
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| 238 | # create a new IPPAttribute from the data we just |
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| 239 | # read in, and add it to our attributes list |
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| 240 | self.attributes.append(IPPAttribute( |
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| 241 | attribute_tag, |
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| 242 | [IPPValue(value_tag, name, value)])) |
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| 243 | |
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| 244 | # otherwise, we're still in the process of reading the |
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| 245 | # current attribute (now we'll read in another value) |
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| 246 | else: |
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| 247 | |
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| 248 | value_tag = next_byte |
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| 249 | # read in the length of the name (two bytes) -- |
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| 250 | # this should be 0x0 |
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| 251 | name_length = request.read(2) |
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| 252 | assert name_length == zero_name_length |
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| 253 | # name should be empty |
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| 254 | name = None |
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| 255 | # read in the length of the value (two bytes) |
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| 256 | value_length = request.read(2) |
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| 257 | # read in the value (value_length bytes) |
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| 258 | value = request.read(value_length) |
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| 259 | |
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| 260 | # add another value to the last attribute |
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| 261 | self.attributes[-1].values.append(IPPValue(value_tag, name, value)) |
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| 262 | |
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| 263 | # read another byte |
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| 264 | next_byte = request.read(1) |
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| 265 | |
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| 266 | # once we hit the end-of-attributes tag, the only thing |
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| 267 | # left is the data, so go ahead and read all of it |
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| 268 | self.data = request.read() |
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| 269 | |
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| 270 | # otherwise, just set the class variables to the keyword |
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| 271 | # arguments passed in |
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| 272 | else: |
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| 273 | self.version = version |
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| 274 | self.operation_id = operation_id |
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| 275 | self.request_id = request_id |
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| 276 | self.attributes = attributes |
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| 277 | self.data = data |
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