Total Complexity | 56 |
Total Lines | 411 |
Duplicated Lines | 34.31 % |
Coverage | 35.14% |
Changes | 0 |
Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like build.v0x04.match_fields often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
1 | """OpenFlow 1.3 OXM match fields. |
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2 | |||
3 | Flow's match is very different from OF 1.0. Instead of always having all |
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4 | fields, there's a variable list of match fields and each one is an Openflow |
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5 | eXtended Match Type-Length-Value (OXM TLV) element. |
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6 | |||
7 | This module provides high-level Python classes for OXM TLV fields in order to |
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8 | make the OF 1.3 match fields easy to use and to be coded. |
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9 | """ |
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10 | 1 | from abc import ABC, abstractmethod |
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11 | |||
12 | 1 | from pyof.foundation.basic_types import HWAddress, IPAddress |
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13 | 1 | from pyof.v0x04.common.flow_match import OxmOfbMatchField, OxmTLV, VlanId |
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14 | |||
15 | |||
16 | 1 | def mask_to_bytes(mask, size): |
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17 | """Return the mask in bytes.""" |
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18 | bits = 0 |
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19 | for i in range(size-mask, size): |
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20 | bits |= (1 << i) |
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21 | tobytes = bits.to_bytes(size//8, 'big') |
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22 | return tobytes |
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23 | |||
24 | |||
25 | 1 | View Code Duplication | def bytes_to_mask(tobytes, size): |
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26 | """Return the mask in string.""" |
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27 | int_mask = int.from_bytes(tobytes, 'big') |
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28 | bits = bin(int_mask) |
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29 | strbits = str(bits) |
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30 | strbits = strbits[2:] |
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31 | netmask = 0 |
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32 | for i in range(size): |
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33 | if strbits[i] == '1': |
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34 | netmask += 1 |
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35 | else: |
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36 | break |
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37 | return netmask |
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38 | |||
39 | |||
40 | 1 | class MatchField(ABC): |
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41 | """Base class for match fields. Abstract OXM TLVs of python-openflow. |
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42 | |||
43 | Just extend this class and you will be forced to define the required |
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44 | low-level attributes and methods below: |
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45 | |||
46 | * "name" attribute (field name to be displayed in JSON); |
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47 | * "oxm_field" attribute (``OxmOfbMatchField`` enum); |
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48 | * Method to return a pyof OxmTLV; |
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49 | * Method to create an instance from an OxmTLV. |
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50 | """ |
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51 | |||
52 | 1 | def __init__(self, value): |
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53 | """Define match field value.""" |
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54 | self.value = value |
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55 | |||
56 | 1 | @property |
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57 | 1 | @classmethod |
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58 | 1 | @abstractmethod |
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59 | def name(cls): |
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60 | """Define a name to be displayed in JSON. |
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61 | |||
62 | It can be overriden just by a class attibute. |
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63 | """ |
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64 | |||
65 | 1 | @property |
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66 | 1 | @classmethod |
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67 | 1 | @abstractmethod |
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68 | def oxm_field(cls): |
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69 | """Define this subclass ``OxmOfbMatchField`` value. |
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70 | |||
71 | It can be overriden just by as a class attibute. |
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72 | """ |
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73 | |||
74 | 1 | @abstractmethod |
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75 | def as_of_tlv(self): |
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76 | """Return a pyof OXM TLV instance.""" |
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77 | |||
78 | 1 | @classmethod |
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79 | 1 | @abstractmethod |
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80 | def from_of_tlv(cls, tlv): |
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81 | """Return an instance from a pyof OXM TLV.""" |
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82 | |||
83 | 1 | def __eq__(self, other): |
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84 | """Two objects are equal if their values are the same. |
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85 | |||
86 | The oxm_field equality is checked indirectly when comparing whether |
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87 | the objects are instances of the same class. |
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88 | """ |
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89 | return isinstance(other, self.__class__) and other.value == self.value |
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90 | |||
91 | |||
92 | 1 | class MatchDLVLAN(MatchField): |
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93 | """Match for datalink VLAN ID.""" |
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94 | |||
95 | 1 | name = 'dl_vlan' |
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96 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_VLAN_VID |
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97 | |||
98 | 1 | def as_of_tlv(self): |
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99 | """Return a pyof OXM TLV instance.""" |
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100 | try: |
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101 | value = int(self.value) |
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102 | mask = None |
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103 | oxm_hasmask = False |
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104 | except ValueError: |
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105 | value, mask = map(int, self.value.split('/')) |
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106 | oxm_hasmask = True |
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107 | value = value | VlanId.OFPVID_PRESENT |
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108 | value_bytes = value.to_bytes(2, 'big') |
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109 | if mask: |
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110 | mask = mask | VlanId.OFPVID_PRESENT |
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111 | value_bytes += mask.to_bytes(2, 'big') |
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112 | return OxmTLV(oxm_field=self.oxm_field, |
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113 | oxm_hasmask=oxm_hasmask, |
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114 | oxm_value=value_bytes) |
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115 | |||
116 | 1 | @classmethod |
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117 | def from_of_tlv(cls, tlv): |
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118 | """Return an instance from a pyof OXM TLV.""" |
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119 | vlan_id = int.from_bytes(tlv.oxm_value[:2], 'big') & 4095 |
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120 | value = vlan_id |
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121 | if tlv.oxm_hasmask: |
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122 | vlan_mask = int.from_bytes(tlv.oxm_value[2:], 'big') & 4095 |
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123 | value = f'{vlan_id}/{vlan_mask}' |
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124 | return cls(value) |
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125 | |||
126 | |||
127 | 1 | class MatchDLVLANPCP(MatchField): |
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128 | """Match for VLAN Priority Code Point.""" |
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129 | |||
130 | 1 | name = 'dl_vlan_pcp' |
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131 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_VLAN_PCP |
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132 | |||
133 | 1 | def as_of_tlv(self): |
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134 | """Return a pyof OXM TLV instance.""" |
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135 | value_bytes = self.value.to_bytes(1, 'big') |
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136 | return OxmTLV(oxm_field=self.oxm_field, oxm_value=value_bytes) |
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137 | |||
138 | 1 | @classmethod |
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139 | def from_of_tlv(cls, tlv): |
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140 | """Return an instance from a pyof OXM TLV.""" |
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141 | priority = int.from_bytes(tlv.oxm_value, 'big') |
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142 | return cls(priority) |
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143 | |||
144 | |||
145 | 1 | View Code Duplication | class MatchDLSrc(MatchField): |
146 | """Match for datalink source.""" |
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147 | |||
148 | 1 | name = 'dl_src' |
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149 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_ETH_SRC |
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150 | |||
151 | 1 | def as_of_tlv(self): |
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152 | """Return a pyof OXM TLV instance.""" |
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153 | if '/' in self.value: |
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154 | value, mask = self.value.split('/') |
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155 | if mask.upper() == 'FF:FF:FF:FF:FF:FF': |
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156 | mask = None |
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157 | oxm_hasmask = False |
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158 | else: |
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159 | mask = mask.upper() |
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160 | oxm_hasmask = True |
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161 | else: |
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162 | value = self.value |
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163 | mask = None |
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164 | oxm_hasmask = False |
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165 | value_bytes = HWAddress(value).pack() |
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166 | if mask: |
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167 | value_bytes += HWAddress(mask).pack() |
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168 | return OxmTLV(oxm_field=self.oxm_field, |
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169 | oxm_hasmask=oxm_hasmask, |
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170 | oxm_value=value_bytes) |
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171 | |||
172 | 1 | @classmethod |
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173 | def from_of_tlv(cls, tlv): |
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174 | """Return an instance from a pyof OXM TLV.""" |
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175 | hw_address = HWAddress() |
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176 | hw_address.unpack(tlv.oxm_value) |
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177 | addr_str = str(hw_address) |
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178 | value = addr_str |
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179 | if tlv.oxm_hasmask: |
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180 | hw_mask = HWAddress() |
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181 | hw_mask.unpack(tlv.oxm_value[6:]) |
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182 | mask_str = str(hw_mask) |
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183 | value = f'{addr_str}/{mask_str}' |
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184 | return cls(value) |
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185 | |||
186 | |||
187 | 1 | View Code Duplication | class MatchDLDst(MatchField): |
188 | """Match for datalink destination.""" |
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189 | |||
190 | 1 | name = 'dl_dst' |
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191 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_ETH_DST |
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192 | |||
193 | 1 | def as_of_tlv(self): |
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194 | """Return a pyof OXM TLV instance.""" |
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195 | if '/' in self.value: |
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196 | value, mask = self.value.split('/') |
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197 | if mask.upper() == 'FF:FF:FF:FF:FF:FF': |
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198 | mask = None |
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199 | oxm_hasmask = False |
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200 | else: |
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201 | mask = mask.upper() |
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202 | oxm_hasmask = True |
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203 | else: |
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204 | value = self.value |
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205 | mask = None |
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206 | oxm_hasmask = False |
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207 | value_bytes = HWAddress(value).pack() |
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208 | if mask: |
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209 | value_bytes += HWAddress(mask).pack() |
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210 | return OxmTLV(oxm_field=self.oxm_field, |
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211 | oxm_hasmask=oxm_hasmask, |
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212 | oxm_value=value_bytes) |
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213 | |||
214 | 1 | @classmethod |
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215 | def from_of_tlv(cls, tlv): |
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216 | """Return an instance from a pyof OXM TLV.""" |
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217 | hw_address = HWAddress() |
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218 | hw_address.unpack(tlv.oxm_value) |
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219 | addr_str = str(hw_address) |
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220 | value = addr_str |
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221 | if tlv.oxm_hasmask: |
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222 | hw_mask = HWAddress() |
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223 | hw_mask.unpack(tlv.oxm_value[6:]) |
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224 | mask_str = str(hw_mask) |
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225 | value = f'{addr_str}/{mask_str}' |
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226 | return cls(value) |
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227 | |||
228 | |||
229 | 1 | class MatchDLType(MatchField): |
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230 | """Match for datalink type.""" |
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231 | |||
232 | 1 | name = 'dl_type' |
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233 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_ETH_TYPE |
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234 | |||
235 | 1 | def as_of_tlv(self): |
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236 | """Return a pyof OXM TLV instance.""" |
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237 | value_bytes = self.value.to_bytes(2, 'big') |
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238 | return OxmTLV(oxm_field=self.oxm_field, oxm_value=value_bytes) |
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239 | |||
240 | 1 | @classmethod |
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241 | def from_of_tlv(cls, tlv): |
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242 | """Return an instance from a pyof OXM TLV.""" |
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243 | port = int.from_bytes(tlv.oxm_value, 'big') |
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244 | return cls(port) |
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245 | |||
246 | |||
247 | 1 | View Code Duplication | class MatchNwSrc(MatchField): |
248 | """Match for IPV4 source.""" |
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249 | |||
250 | 1 | name = 'nw_src' |
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251 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_IPV4_SRC |
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252 | |||
253 | 1 | def as_of_tlv(self): |
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254 | """Return a pyof OXM TLV instance.""" |
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255 | ip_addr = IPAddress(self.value) |
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256 | value_bytes = ip_addr.pack() |
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257 | if ip_addr.netmask < 32: |
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258 | value_bytes += mask_to_bytes(ip_addr.netmask, 32) |
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259 | return OxmTLV(oxm_field=self.oxm_field, |
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260 | oxm_hasmask=ip_addr.netmask < 32, |
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261 | oxm_value=value_bytes) |
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262 | |||
263 | 1 | @classmethod |
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264 | def from_of_tlv(cls, tlv): |
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265 | """Return an instance from a pyof OXM TLV.""" |
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266 | ip_address = IPAddress() |
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267 | ip_address.unpack(tlv.oxm_value) |
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268 | value = str(ip_address) |
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269 | if tlv.oxm_hasmask: |
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270 | value = f'{value}/{bytes_to_mask(tlv.oxm_value[4:], 32)}' |
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271 | return cls(value) |
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272 | |||
273 | |||
274 | 1 | View Code Duplication | class MatchNwDst(MatchField): |
275 | """Match for IPV4 destination.""" |
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276 | |||
277 | 1 | name = 'nw_dst' |
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278 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_IPV4_DST |
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279 | |||
280 | 1 | def as_of_tlv(self): |
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281 | """Return a pyof OXM TLV instance.""" |
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282 | ip_addr = IPAddress(self.value) |
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283 | value_bytes = ip_addr.pack() |
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284 | if ip_addr.netmask < 32: |
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285 | value_bytes += mask_to_bytes(ip_addr.netmask, 32) |
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286 | return OxmTLV(oxm_field=self.oxm_field, |
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287 | oxm_hasmask=ip_addr.netmask < 32, |
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288 | oxm_value=value_bytes) |
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289 | |||
290 | 1 | @classmethod |
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291 | def from_of_tlv(cls, tlv): |
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292 | """Return an instance from a pyof OXM TLV.""" |
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293 | ip_address = IPAddress() |
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294 | ip_address.unpack(tlv.oxm_value) |
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295 | value = str(ip_address) |
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296 | if tlv.oxm_hasmask: |
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297 | value = f'{value}/{bytes_to_mask(tlv.oxm_value[4:], 32)}' |
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298 | return cls(value) |
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299 | |||
300 | |||
301 | 1 | class MatchNwProto(MatchField): |
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302 | """Match for IP protocol.""" |
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303 | |||
304 | 1 | name = 'nw_proto' |
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305 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_IP_PROTO |
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306 | |||
307 | 1 | def as_of_tlv(self): |
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308 | """Return a pyof OXM TLV instance.""" |
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309 | value_bytes = self.value.to_bytes(1, 'big') |
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310 | return OxmTLV(oxm_field=self.oxm_field, oxm_value=value_bytes) |
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311 | |||
312 | 1 | @classmethod |
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313 | def from_of_tlv(cls, tlv): |
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314 | """Return an instance from a pyof OXM TLV.""" |
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315 | priority = int.from_bytes(tlv.oxm_value, 'big') |
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316 | return cls(priority) |
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317 | |||
318 | |||
319 | 1 | class MatchInPort(MatchField): |
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320 | """Match for input port.""" |
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321 | |||
322 | 1 | name = 'in_port' |
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323 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_IN_PORT |
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324 | |||
325 | 1 | def as_of_tlv(self): |
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326 | """Return a pyof OXM TLV instance.""" |
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327 | value_bytes = self.value.to_bytes(4, 'big') |
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328 | return OxmTLV(oxm_field=self.oxm_field, oxm_value=value_bytes) |
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329 | |||
330 | 1 | @classmethod |
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331 | def from_of_tlv(cls, tlv): |
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332 | """Return an instance from a pyof OXM TLV.""" |
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333 | port = int.from_bytes(tlv.oxm_value, 'big') |
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334 | return cls(port) |
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335 | |||
336 | |||
337 | 1 | class MatchTCPSrc(MatchField): |
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338 | """Match for TCP source.""" |
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339 | |||
340 | 1 | name = 'tp_src' |
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341 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_TCP_SRC |
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342 | |||
343 | 1 | def as_of_tlv(self): |
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344 | """Return a pyof OXM TLV instance.""" |
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345 | value_bytes = self.value.to_bytes(2, 'big') |
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346 | return OxmTLV(oxm_field=self.oxm_field, oxm_value=value_bytes) |
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347 | |||
348 | 1 | @classmethod |
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349 | def from_of_tlv(cls, tlv): |
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350 | """Return an instance from a pyof OXM TLV.""" |
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351 | port = int.from_bytes(tlv.oxm_value, 'big') |
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352 | return cls(port) |
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353 | |||
354 | |||
355 | 1 | class MatchTCPDst(MatchField): |
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356 | """Match for TCP destination.""" |
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357 | |||
358 | 1 | name = 'tp_dst' |
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359 | 1 | oxm_field = OxmOfbMatchField.OFPXMT_OFB_TCP_DST |
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360 | |||
361 | 1 | def as_of_tlv(self): |
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362 | """Return a pyof OXM TLV instance.""" |
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363 | value_bytes = self.value.to_bytes(2, 'big') |
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364 | return OxmTLV(oxm_field=self.oxm_field, oxm_value=value_bytes) |
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365 | |||
366 | 1 | @classmethod |
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367 | def from_of_tlv(cls, tlv): |
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368 | """Return an instance from a pyof OXM TLV.""" |
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369 | port = int.from_bytes(tlv.oxm_value, 'big') |
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370 | return cls(port) |
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371 | |||
372 | |||
373 | 1 | class MatchFieldFactory(ABC): |
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374 | """Create the correct MatchField subclass instance. |
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375 | |||
376 | As OF 1.3 has many match fields and there are many ways to (un)pack their |
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377 | OxmTLV.oxm_value, this class does all the work of finding the correct |
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378 | MatchField class and instantiating the corresponding object. |
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379 | """ |
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380 | |||
381 | 1 | __classes = {} |
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382 | |||
383 | 1 | @classmethod |
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384 | def from_name(cls, name, value): |
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385 | """Return the proper object from name and value.""" |
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386 | field_class = cls._get_class(name) |
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387 | if field_class: |
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388 | return field_class(value) |
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389 | return None |
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390 | |||
391 | 1 | @classmethod |
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392 | def from_of_tlv(cls, tlv): |
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393 | """Return the proper object from a pyof OXM TLV.""" |
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394 | field_class = cls._get_class(tlv.oxm_field) |
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395 | if field_class: |
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396 | return field_class.from_of_tlv(tlv) |
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397 | return None |
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398 | |||
399 | 1 | @classmethod |
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400 | def _get_class(cls, name_or_field): |
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401 | """Return the proper object from field name or OxmTLV.oxm_field.""" |
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402 | if not cls.__classes: |
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403 | cls._index_classes() |
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404 | return cls.__classes.get(name_or_field) |
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405 | |||
406 | 1 | @classmethod |
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407 | def _index_classes(cls): |
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408 | for subclass in MatchField.__subclasses__(): |
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409 | cls.__classes[subclass.name] = subclass |
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410 | cls.__classes[subclass.oxm_field] = subclass |
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411 |