Convert my MAC Address into byte array when build packet

Question

I want to build simple DHCP packet and one of the protocol oprion is client mac address (option 61), so i have my mac address:

string macAddress = "00:14:22:18:81:11";

and i want to put it in my packet array (6 bytes), this is what i have try and i wonder how to do that (i try to convert my string into byte[] but this array length is 24)

        // Set requested ip address - 61
        index += DHCPMessageTypeLength;
        packetArrayBytes[index] = 61; // option 
        packetArrayBytes[index + 1] = 7; // length
        packetArrayBytes[index + 2] = 1; // hardware type Ethernet
        packetArrayBytes[index + 3] = ?; // mac
        packetArrayBytes[index + 4] = ?; // mac
        packetArrayBytes[index + 5] = ?; // mac
        packetArrayBytes[index + 6] = ?; // mac
        packetArrayBytes[index + 7] = ?; // mac
        packetArrayBytes[index + 8] = ?; // mac

JPG · Accepted Answer · 2015-12-09 09:00:32Z

2

Here is my proposal:

List<byte> packet = new List<byte>();
packet.AddRange(new byte[] { 61, 7, 1 });
packet.AddRange(macAddress.Split(':').Select(b => Convert.ToByte(b, 16)));

Array.Copy(packet.ToArray(), 0, packetArrayBytes, DHCPMessageTypeLength, packet.Count);

edited Dec 9, 2015 at 9:00

answered Jun 4, 2014 at 9:39

JPG

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2 Comments

Bosiwow Over a year ago

macAddress.Split(':').Select(b => Convert.ToByte(b)) gives errors for me when the string contains letters (A,B,C,D,E,F) :(

JPG Over a year ago

@Bosiwow Thanks for pointing this out, I forgot to specify base 16 for hex conversion. See edited answer.

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