Initial commit for gocast

controller/system.go

@@ -0,0 +1,52 @@
+package controller
+
+import (
+	"fmt"
+	"net"
+	"os/exec"
+	"strings"
+)
+
+func gateway() (net.IP, error) {
+	cmd := `ip route | grep "^default" | cut -d" " -f3`
+	out, err := exec.Command("bash", "-c", cmd).Output()
+	if err != nil {
+		return nil, fmt.Errorf("Failed to execute command: %s", cmd)
+	}
+	return net.ParseIP(strings.TrimSpace(string(out))), nil
+}
+
+func localAddress(gw net.IP) (net.IP, error) {
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		return nil, err
+	}
+	for _, addr := range addrs {
+		switch v := addr.(type) {
+		case *net.IPNet:
+			if v.Contains(gw) {
+				return v.IP, nil
+			}
+		}
+	}
+	return nil, fmt.Errorf("Unable to find local address")
+}
+
+func addLoopback(name string, addr *net.IPNet) error {
+	mask := fmt.Sprintf("%d.%d.%d.%d", addr.Mask[0], addr.Mask[1], addr.Mask[2], addr.Mask[3])
+	cmd := fmt.Sprintf("ifconfig lo:%s %s netmask %s up", name, addr.IP.String(), mask)
+	_, err := exec.Command("bash", "-c", cmd).Output()
+	if err != nil {
+		return fmt.Errorf("Failed to Add loopback command: %v", err)
+	}
+	return nil
+}
+
+func deleteLoopback(name string) error {
+	cmd := fmt.Sprintf("ifconfig lo:%s down", name)
+	_, err := exec.Command("bash", "-c", cmd).Output()
+	if err != nil {
+		return fmt.Errorf("Failed to delete loopback command: %v", err)
+	}
+	return nil
+}