[Threading] Crash ping.(*Pinger).recvICMP

Hi there,

not sure if it's on the usage or library side, but I create a new pinger in a thread calling pinger like this:

func ping_host(host string, count int, timeout int) error {
    pinger, err := ping.NewPinger(host)
    if err != nil {
        return err
    }

    if runtime.GOOS == "windows" {
        // Windows requires SetPrivileged
        pinger.SetPrivileged(true)
    } else {
        // others can perfectly well do that with a system setting
        // either
        // setcap cap_net_raw=+ep /opt/slacheck/slacheck
        // or
        // sudo sysctl -w net.ipv4.ping_group_range="0 2147483647"

        pinger.SetPrivileged(false)
    }

    pinger.Timeout = time.Second * time.Duration(timeout*count)
    pinger.Interval = time.Second * time.Duration(timeout)
    pinger.Count = count

    err = pinger.Run()

    if err != nil {
        return err
    }

    stats := pinger.Statistics()
    if stats.PacketLoss == 100 {
        return errors.New("Host Timeout: " + host)
    }

    return nil
}

Once in a while (every 400-600 hosts I ping) I get the following crash:

panic: close of closed channel

goroutine 3301 [running]:
github.com/go-ping/ping.(*Pinger).recvICMP(0xc00005f540, 0xc001b02260, 0xc0011286c0, 0xc0018ac7e0, 0x0, 0x0)
        C:/Users/ngrgeo/devel/go/pkg/mod/github.com/go-ping/ping@v0.0.0-20210312085107-d90f3778a8a3/ping.go:518 +0x372
created by github.com/go-ping/ping.(*Pinger).Run
        C:/Users/ngrgeo/devel/go/pkg/mod/github.com/go-ping/ping@v0.0.0-20210312085107-d90f3778a8a3/ping.go:401 +0x299

This may be a bug in the threading / mutexes, seems recvICMP is not really thread safe? That said, I'm running 100 threads in parallel (have to ping a few thousand hosts).

I didn't take a closer look into the implementation yet, but I thought I'll raise the issue - can still work on that later.

//G

go-ping / ping

[Threading] Crash ping.(*Pinger).recvICMP #157