通过GO中的原始套接字读取TCP数据包

Question

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)
    }
}

Answer 1

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