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1# Impacket - Collection of Python classes for working with network protocols. 

2# 

3# SECUREAUTH LABS. Copyright (C) 2021 SecureAuth Corporation. All rights reserved. 

4# 

5# This software is provided under a slightly modified version 

6# of the Apache Software License. See the accompanying LICENSE file 

7# for more information. 

8# 

9 

10import struct 

11import array 

12 

13from impacket.ImpactPacket import Header, array_frombytes 

14from impacket.IP6_Address import IP6_Address 

15from impacket.IP6_Extension_Headers import IP6_Extension_Header 

16 

17from impacket import LOG 

18 

19 

20class IP6(Header): 

21 #Ethertype value for IPv6 

22 ethertype = 0x86DD 

23 HEADER_SIZE = 40 

24 IP_PROTOCOL_VERSION = 6 

25 

26 def __init__(self, buffer = None): 

27 Header.__init__(self, IP6.HEADER_SIZE) 

28 self.set_ip_v(IP6.IP_PROTOCOL_VERSION) 

29 if (buffer): 

30 self.load_header(buffer) 

31 

32 def contains(self, aHeader): 

33 Header.contains(self, aHeader) 

34 if isinstance(aHeader, IP6_Extension_Header): 

35 self.set_next_header(aHeader.get_header_type()) 

36 

37 def get_header_size(self): 

38 return IP6.HEADER_SIZE 

39 

40 def __str__(self): 

41 protocol_version = self.get_ip_v() 

42 traffic_class = self.get_traffic_class() 

43 flow_label = self.get_flow_label() 

44 payload_length = self.get_payload_length() 

45 next_header = self.get_next_header() 

46 hop_limit = self.get_hop_limit() 

47 source_address = self.get_ip_src() 

48 destination_address = self.get_ip_dst() 

49 

50 s = "Protocol version: " + str(protocol_version) + "\n" 

51 s += "Traffic class: " + str(traffic_class) + "\n" 

52 s += "Flow label: " + str(flow_label) + "\n" 

53 s += "Payload length: " + str(payload_length) + "\n" 

54 s += "Next header: " + str(next_header) + "\n" 

55 s += "Hop limit: " + str(hop_limit) + "\n" 

56 s += "Source address: " + source_address.as_string() + "\n" 

57 s += "Destination address: " + destination_address.as_string() + "\n" 

58 return s 

59 

60 def get_pseudo_header(self): 

61 source_address = self.get_ip_src().as_bytes() 

62 #FIXME - Handle Routing header special case 

63 destination_address = self.get_ip_dst().as_bytes() 

64 reserved_bytes = [ 0x00, 0x00, 0x00 ] 

65 

66 upper_layer_packet_length = self.get_payload_length() 

67 upper_layer_protocol_number = self.get_next_header() 

68 

69 next_header = self.child() 

70 while isinstance(next_header, IP6_Extension_Header): 70 ↛ 73line 70 didn't jump to line 73, because the condition on line 70 was never true

71 # The length used in the pseudo-header is the Payload Length from the IPv6 header, minus 

72 # the length of any extension headers present between the IPv6 header and the upper-layer header 

73 upper_layer_packet_length -= next_header.get_header_size() 

74 

75 # If there are extension headers, fetch the correct upper-player protocol number by traversing the list 

76 upper_layer_protocol_number = next_header.get_next_header() 

77 

78 next_header = next_header.child() 

79 

80 pseudo_header = array.array('B') 

81 pseudo_header.extend(source_address) 

82 pseudo_header.extend(destination_address) 

83 array_frombytes(pseudo_header, struct.pack('!L', upper_layer_packet_length)) 

84 pseudo_header.fromlist(reserved_bytes) 

85 array_frombytes(pseudo_header, struct.pack('B', upper_layer_protocol_number)) 

86 return pseudo_header 

87 

88############################################################################ 

89 def get_ip_v(self): 

90 return (self.get_byte(0) & 0xF0) >> 4 

91 

92 def get_traffic_class(self): 

93 return ((self.get_byte(0) & 0x0F) << 4) | ((self.get_byte(1) & 0xF0) >> 4) 

94 

95 def get_flow_label(self): 

96 return (self.get_byte(1) & 0x0F) << 16 | (self.get_byte(2) << 8) | self.get_byte(3) 

97 

98 def get_payload_length(self): 

99 return (self.get_byte(4) << 8) | self.get_byte(5) 

100 

101 def get_next_header(self): 

102 return (self.get_byte(6)) 

103 

104 def get_hop_limit(self): 

105 return (self.get_byte(7)) 

106 

107 def get_ip_src(self): 

108 address = IP6_Address(self.get_bytes()[8:24]) 

109 return (address) 

110 

111 def get_ip_dst(self): 

112 address = IP6_Address(self.get_bytes()[24:40]) 

113 return (address) 

114 

115############################################################################ 

116 def set_ip_v(self, version): 

117 if (version != 6): 117 ↛ 118line 117 didn't jump to line 118, because the condition on line 117 was never true

118 raise Exception('set_ip_v - version != 6') 

119 

120 #Fetch byte, clear high nibble 

121 b = self.get_byte(0) & 0x0F 

122 #Store version number in high nibble 

123 b |= (version << 4) 

124 #Store byte in buffer 

125 #This behaviour is repeated in the rest of the methods  

126 self.set_byte(0, b) 

127 

128 

129 def set_traffic_class(self, traffic_class): 

130 b0 = self.get_byte(0) & 0xF0 

131 b1 = self.get_byte(1) & 0x0F 

132 b0 |= (traffic_class & 0xF0) >> 4 

133 b1 |= (traffic_class & 0x0F) << 4 

134 self.set_byte(0, b0) 

135 self.set_byte(1, b1) 

136 

137 

138 def set_flow_label(self, flow_label): 

139 b1 = self.get_byte(1) & 0xF0 

140 b1 |= (flow_label & 0xF0000) >> 16 

141 self.set_byte(1, b1) 

142 self.set_byte(2, (flow_label & 0x0FF00) >> 8) 

143 self.set_byte(3, (flow_label & 0x000FF)) 

144 

145 

146 def set_payload_length(self, payload_length): 

147 self.set_byte(4, (payload_length & 0xFF00) >> 8) 

148 self.set_byte(5, (payload_length & 0x00FF)) 

149 

150 

151 def set_next_header(self, next_header): 

152 self.set_byte(6, next_header) 

153 

154 def set_hop_limit(self, hop_limit): 

155 self.set_byte(7, hop_limit) 

156 

157 def set_ip_src(self, source_address): 

158 address = IP6_Address(source_address) 

159 bytes = self.get_bytes() 

160 bytes[8:24] = address.as_bytes() 

161 self.set_bytes(bytes) 

162 

163 def set_ip_dst(self, destination_address): 

164 address = IP6_Address(destination_address) 

165 bytes = self.get_bytes() 

166 bytes[24:40] = address.as_bytes() 

167 self.set_bytes(bytes) 

168 

169 def get_protocol_version(self): 

170 LOG.warning('deprecated soon') 

171 return self.get_ip_v() 

172 

173 def get_source_address(self): 

174 LOG.warning('deprecated soon') 

175 return self.get_ip_src() 

176 

177 def get_destination_address(self): 

178 LOG.warning('deprecated soon') 

179 return self.get_ip_dst() 

180 

181 def set_protocol_version(self, version): 

182 LOG.warning('deprecated soon') 

183 self.set_ip_v(version) 

184 

185 def set_source_address(self, source_address): 

186 LOG.warning('deprecated soon') 

187 self.set_ip_src(source_address) 

188 

189 def set_destination_address(self, destination_address): 

190 LOG.warning('deprecated soon') 

191 self.set_ip_dst(destination_address)