From 118fbcdd6510a1a449b1aacf451db60aa72dd804 Mon Sep 17 00:00:00 2001
From: pg9182 <96569817+pg9182@users.noreply.github.com>
Date: Wed, 8 Mar 2023 19:48:50 -0500
Subject: cmd/r2-a2s-probe: Use new nspkt package

---
 cmd/r2-a2s-probe/main.go | 65 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 61 insertions(+), 4 deletions(-)

diff --git a/cmd/r2-a2s-probe/main.go b/cmd/r2-a2s-probe/main.go
index dd38b7d..9e60edc 100644
--- a/cmd/r2-a2s-probe/main.go
+++ b/cmd/r2-a2s-probe/main.go
@@ -2,25 +2,32 @@
 package main
 
 import (
+	"context"
 	"fmt"
+	"math/rand"
+	"net"
 	"net/netip"
 	"os"
 	"sync"
 	"time"
 
-	"github.com/r2northstar/atlas/pkg/a2s"
+	"github.com/r2northstar/atlas/pkg/nspkt"
 	"github.com/spf13/pflag"
 )
 
 var opt struct {
+	Addr        string
 	Connections int
 	Timeout     time.Duration
+	Interval    time.Duration
 	Silent      bool
 	Help        bool
 }
 
 func init() {
+	pflag.StringVarP(&opt.Addr, "listen", "a", "[::]:0", "UDP listen address")
 	pflag.DurationVarP(&opt.Timeout, "timeout", "t", time.Second*3, "Amount of time to wait for a response")
+	pflag.DurationVarP(&opt.Interval, "interval", "i", time.Second, "Interval to send packets at")
 	pflag.IntVarP(&opt.Connections, "connections", "c", 1, "Number of concurrent connections")
 	pflag.BoolVarP(&opt.Silent, "silent", "s", false, "Don't show the result")
 	pflag.BoolVarP(&opt.Help, "help", "h", false, "Show this help text")
@@ -37,8 +44,9 @@ func main() {
 		os.Exit(0)
 	}
 
-	if opt.Connections < 1 {
-		fmt.Fprintf(os.Stderr, "fatal: --connections must be at least 1\n")
+	uaddr, err := netip.ParseAddrPort(opt.Addr)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "fatal: invalid udp listen address: %v\n", err)
 		os.Exit(2)
 	}
 
@@ -48,6 +56,15 @@ func main() {
 		os.Exit(2)
 	}
 
+	conn, err := net.ListenUDP("udp", net.UDPAddrFromAddrPort(uaddr))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "fatal: %v\n", err)
+		os.Exit(2)
+	}
+
+	l := nspkt.NewListener()
+	go l.Serve(conn)
+
 	queue := make(chan int)
 	go func() {
 		defer close(queue)
@@ -66,9 +83,12 @@ func main() {
 	for n := 0; n < opt.Connections; n++ {
 		wg.Add(1)
 		go func() {
+			ctx, cancel := context.WithTimeout(context.Background(), opt.Timeout)
+			defer cancel()
+
 			defer wg.Done()
 			for i := range queue {
-				res <- Result{i, a2s.Probe(addr[i], opt.Timeout)}
+				res <- Result{i, probe(ctx, addr[i], l)}
 			}
 		}()
 	}
@@ -95,6 +115,43 @@ func main() {
 	}
 }
 
+func probe(ctx context.Context, addr netip.AddrPort, l *nspkt.Listener) error {
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	uid := rand.Uint64()
+
+	x := make(chan error, 1)
+	go func() {
+		t := time.NewTicker(opt.Interval)
+		defer t.Stop()
+
+		for {
+			if err := l.SendConnect(addr, uid); err != nil {
+				select {
+				case x <- err:
+				default:
+				}
+			}
+			select {
+			case <-ctx.Done():
+				return
+			case <-t.C:
+			}
+		}
+	}()
+
+	err := l.WaitConnectReply(ctx, addr, uid)
+	if err != nil {
+		select {
+		case err = <-x:
+			// error could be due to an issue sending the packet
+		default:
+		}
+	}
+	return err
+}
+
 func parseAddrPorts(a []string) ([]netip.AddrPort, error) {
 	r := make([]netip.AddrPort, len(a))
 	for i, x := range a {
-- 
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