Icmp checksum code#

When calculating the checksum, you need addition and bitwise operations and should use an integer type like uint32. I suggest you make a function that takes a byte slice, and calculates and returns the Internet checksum. Set request identifier in hdr and sequence number in hdr. You can address bytes in byte slices directly and append to byte slices. When representing a packet in Go, you would usually use byte slices at some level. Why do you say you need to do AND 0xFFFFFF? I don't see how that would be useful when calculating an Internet checksum.

Icmp checksum code#

BTW, the ICMP header checksum needs to be calculated over the whole header, not only over the type and code fields.

Why? The ICMP code of an echo request is zero, not 128 (0x80). However, the example then says the equivalent of myICMPCode := 0x80. sizeof(int)) / here the icmp packet is created also the ip checksum is. In your example, you use the ICMP type 8. pinger.c This is a ping imitation program It will send an ICMP ECHO. Why are you decoding hex? Instead of hex.DecodeString('08') and error handling you can just write 0x08 or 8, preferably defined as a constant. You raise several problems, and I'm not sure whether to address the ICMP / TCP/IP parts or the Go parts. I know GO has some good options to speed up this process, but the whole point here is get into the actual weeds with network protocols support by TCP/IP Somehow I'm supposed to do a logic AND operation using 0xFFFFFF on this ( myICMPType + myICMPCode) but I've no idea how should i suppose to concat both of those bytes as a single 16 bit chunk of data. MyICMPCode, err := hex.DecodeString('80') // Code - 128 - (8 bits) MyICMPType, err := hex.DecodeString('08') // Ping Request - 8 - (8 bits) My problem is that for now I've organized the Type and Code header like this I've read that we need to get all the datagram headers to be divided into 16 bit chunks. So one of the topics i got block was the checksum part. As an exercise to push me on studying both the language and the various concepts of network/infra i was trying to implement a ping like tool.