CODEWITHSUNDEEP
socketsgo
Jonathan Eustace
Jonathan Eustace

Reputation: 2489

Reading TCP packets via raw sockets in GO

I'm researching raw sockets in GO. I would like to be able to read all TCP packets going to my computer (OSX, en0: 192.168.1.65)

If I switch the protocol from tcp to icmp, I will get packets. Why do I have no packets being read with my code?

package main

import (
"fmt"
"net"
)

func main() {

    netaddr, err := net.ResolveIPAddr("ip4", "192.168.1.65")
    if err != nil {
        fmt.Println(err)
    }

    conn, err := net.ListenIP("ip4:tcp", netaddr)
    if err != nil {
        fmt.Println(err)
    }

    buf := make([]byte, 2048)
    for {
        numRead, recvAddr, err := conn.ReadFrom(buf)
        if err != nil {
            fmt.Println(err)
        }
        if recvAddr != nil {
            fmt.Println(recvAddr)
        }
        s := string(buf[:numRead])
        fmt.Println(s)
    }
}

Upvotes: 3

Views: 4892

Answers (1)

Jonathan Eustace
Jonathan Eustace

Reputation: 2489

The problem with this is that OS X is based on BSD, and BSD doesn't allow you to program raw sockets at the TCP level. You have to use go down to the Ethernet level in order to do so.

I'm using the pcap library with gopackets to do the job.

https://godoc.org/code.google.com/p/gopacket/pcap

Upvotes: 1

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