init

pkg/iproute/ipip.go

@@ -0,0 +1,59 @@
+// Copyright 2019 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package iproute
+
+import (
+	"bytes"
+	"fmt"
+	"os/exec"
+
+	"github.com/vishvananda/netlink"
+)
+
+const (
+	ipipHeaderSize = 20
+	tunnelName     = "tunl0"
+)
+
+// NewIPIP creates an IPIP interface using the base interface
+// to derive the tunnel's MTU.
+func NewIPIP(baseIndex int) (int, error) {
+	link, err := netlink.LinkByName(tunnelName)
+	if err != nil {
+		// If we failed to find the tunnel, then it probably simply does not exist.
+		cmd := exec.Command("ip", "tunnel", "add", tunnelName, "mode", "ipip")
+		var stderr bytes.Buffer
+		cmd.Stderr = &stderr
+		if err := cmd.Run(); err != nil {
+			return 0, fmt.Errorf("failed to create IPIP tunnel: %s", stderr.String())
+		}
+		link, err = netlink.LinkByName(tunnelName)
+		if err != nil {
+			return 0, fmt.Errorf("failed to get tunnel device: %v", err)
+		}
+	}
+
+	base, err := netlink.LinkByIndex(baseIndex)
+	if err != nil {
+		return 0, fmt.Errorf("failed to get base device: %v", err)
+	}
+
+	mtu := base.Attrs().MTU - ipipHeaderSize
+	if err = netlink.LinkSetMTU(link, mtu); err != nil {
+		return 0, fmt.Errorf("failed to set tunnel MTU: %v", err)
+	}
+
+	return link.Attrs().Index, nil
+}

pkg/iproute/iproute.go

@@ -0,0 +1,70 @@
+// Copyright 2019 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package iproute
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/vishvananda/netlink"
+)
+
+// RemoveInterface removes an interface.
+func RemoveInterface(index int) error {
+	link, err := netlink.LinkByIndex(index)
+	if err != nil {
+		return fmt.Errorf("failed to get link: %s", err)
+	}
+	return netlink.LinkDel(link)
+}
+
+// Set sets the interface up or down.
+func Set(index int, up bool) error {
+	link, err := netlink.LinkByIndex(index)
+	if err != nil {
+		return fmt.Errorf("failed to get link: %s", err)
+	}
+	if up {
+		return netlink.LinkSetUp(link)
+	}
+	return netlink.LinkSetDown(link)
+}
+
+// SetAddress sets the IP address of an interface.
+func SetAddress(index int, cidr *net.IPNet) error {
+	link, err := netlink.LinkByIndex(index)
+	if err != nil {
+		return fmt.Errorf("failed to get link: %s", err)
+	}
+	addrs, err := netlink.AddrList(link, netlink.FAMILY_ALL)
+	if err != nil {
+		return err
+	}
+	l := len(addrs)
+	for _, addr := range addrs {
+		if addr.IP.Equal(cidr.IP) && addr.Mask.String() == cidr.Mask.String() {
+			continue
+		}
+		if err := netlink.AddrDel(link, &addr); err != nil {
+			return fmt.Errorf("failed to delete address: %s", err)
+		}
+		l--
+	}
+	// The only address left is the desired address, so quit.
+	if l == 1 {
+		return nil
+	}
+	return netlink.AddrReplace(link, &netlink.Addr{IPNet: cidr})
+}