do a few

cmd/util.go

@@ -0,0 +1,37 @@
+package cmd
+
+import (
+	"net"
+	"net/netip"
+
+	"github.com/charmbracelet/log"
+)
+
+func runServer(server func(net.Listener) error) {
+	if proto != "tcp" && proto != "udp" {
+		log.Fatal("unsupported protocol, must be either tcp or udp")
+	}
+
+	if v6 {
+		proto += "6"
+	}
+
+	addr, ok := netip.AddrFromSlice(ip)
+	if !ok {
+		log.Fatal("invalid ip")
+	}
+
+	ap := netip.AddrPortFrom(addr, port)
+
+	listener, err := net.Listen(proto, ap.String())
+	if err != nil {
+		log.Fatal("unable to listen", "err", err)
+	}
+
+	log.Info("starting server", "proto", proto, "ip", ip, "port", port)
+
+	err = server(listener)
+	if err != nil {
+		log.Fatal("error while handling connections", "err", err)
+	}
+}