Beispiel #1
0
func configureIface(ifname string, ipn ip.IP4Net, mtu int) error {
	iface, err := netlink.LinkByName(ifname)
	if err != nil {
		return fmt.Errorf("failed to lookup interface %v", ifname)
	}

	err = netlink.AddrAdd(iface, &netlink.Addr{ipn.ToIPNet(), ""})
	if err != nil {
		return fmt.Errorf("failed to add IP address %v to %v: %v", ipn.String(), ifname, err)
	}

	err = netlink.LinkSetMTU(iface, mtu)
	if err != nil {
		return fmt.Errorf("failed to set MTU for %v: %v", ifname, err)
	}

	err = netlink.LinkSetUp(iface)
	if err != nil {
		return fmt.Errorf("failed to set interface %v to UP state: %v", ifname, err)
	}

	// explicitly add a route since there might be a route for a subnet already
	// installed by Docker and then it won't get auto added
	err = netlink.RouteAdd(&netlink.Route{
		LinkIndex: iface.Attrs().Index,
		Scope:     netlink.SCOPE_UNIVERSE,
		Dst:       ipn.Network().ToIPNet(),
	})
	if err != nil && err != syscall.EEXIST {
		return fmt.Errorf("Failed to add route (%v -> %v): %v", ipn.Network().String(), ifname, err)
	}

	return nil
}
Beispiel #2
0
func setupIPMasq(ipn ip.IP4Net) error {
	ipt, err := iptables.New()
	if err != nil {
		return fmt.Errorf("failed to setup IP Masquerade. iptables was not found")
	}

	err = ipt.ClearChain("nat", "FLANNEL")
	if err != nil {
		return fmt.Errorf("Failed to create/clear FLANNEL chain in NAT table: %v", err)
	}

	rules := [][]string{
		// This rule makes sure we don't NAT traffic within overlay network (e.g. coming out of docker0)
		{"FLANNEL", "-d", ipn.String(), "-j", "ACCEPT"},
		// NAT if it's not multicast traffic
		{"FLANNEL", "!", "-d", "224.0.0.0/4", "-j", "MASQUERADE"},
		// This rule will take everything coming from overlay and sent it to FLANNEL chain
		{"POSTROUTING", "-s", ipn.String(), "-j", "FLANNEL"},
	}

	for _, rule := range rules {
		log.Info("Adding iptables rule: ", strings.Join(rule, " "))
		chain := rule[0]
		args := rule[1:len(rule)]

		err = ipt.AppendUnique("nat", chain, args...)
		if err != nil {
			return fmt.Errorf("Failed to insert IP masquerade rule: %v", err)
		}
	}

	return nil
}
Beispiel #3
0
func rules(ipn ip.IP4Net) [][]string {
	n := ipn.String()

	return [][]string{
		// This rule makes sure we don't NAT traffic within overlay network (e.g. coming out of docker0)
		{"-s", n, "-d", n, "-j", "RETURN"},
		// NAT if it's not multicast traffic
		{"-s", n, "!", "-d", "224.0.0.0/4", "-j", "MASQUERADE"},
		// Masquerade anything headed towards flannel from the host
		{"!", "-s", n, "-d", n, "-j", "MASQUERADE"},
	}
}