package main

import (
    "log"
    "os"
    "os/exec"
    "os/signal"
    "time"

    "github.com/google/gopacket/pcap"
)

// Tap is the name of the tap we'll capture traffic from, shouldn't exist
// already otherwise the ip command will fail
const Tap = "testtap"

func main() {
    // Create tap that won't receive any traffic, ever
    cmd := exec.Command("ip", "tuntap", "add", "mode", "tap", Tap)
    if _, err := cmd.CombinedOutput(); err != nil {
        panic(err)
    }
    cmd = exec.Command("ip", "link", "set", Tap, "up")
    if _, err := cmd.CombinedOutput(); err != nil {
        panic(err)
    }   

    // And delete it when we're done
    defer func() {
        cmd := exec.Command("ip", "link", "del", Tap)
        if _, err := cmd.CombinedOutput(); err != nil {
            panic(err)
        }   
    }() 

    // Channel to signal when the pcap reading goroutine is finished
    done := make(chan bool)

    handle, err := pcap.OpenLive(Tap, 1600, true, time.Second)
    if err != nil {
        panic(err)
    }   

    go func() {
        defer close(done)

        var err error
        for err == nil {
            _, _, err = handle.ReadPacketData()
            if err == pcap.NextErrorTimeoutExpired {
                // non-terminating...
                err = nil 
            }   
        }   

        log.Printf("done reading packets: %v", err)
    }() 

    // Wait for Ctrl-C
    sig := make(chan os.Signal, 1024)
    signal.Notify(sig, os.Interrupt)

    <-sig
    log.Print("got SIGTERM, closing handle")

    // Close the handle
    handle.Close()

    // Wait for goroutine to terminate
    <-done
    log.Print("all done")
}

$ sudo ./test 
^C2016/11/09 14:36:22 got SIGTERM, closing handle
2016/11/09 14:36:23 done reading packets: EOF
2016/11/09 14:36:23 all done

$ sudo ./test 
^C2016/11/09 14:36:22 got SIGTERM, closing handle
<hangs>

This means that the read timeout should NOT be used, for example, in an interactive application to allow the packet capture loop to ``poll'' for user input periodically, as there's no guarantee that a call reading packets will return after the timeout expires even if no packets have arrived.