mirror of https://github.com/k3s-io/k3s
197 lines
6.3 KiB
Go
197 lines
6.3 KiB
Go
//
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// Copyright 2015 flannel authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package flannel
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import (
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"fmt"
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"net"
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"os"
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"path/filepath"
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"sync"
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"github.com/flannel-io/flannel/backend"
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"github.com/flannel-io/flannel/network"
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"github.com/flannel-io/flannel/pkg/ip"
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"github.com/flannel-io/flannel/subnet/kube"
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"github.com/sirupsen/logrus"
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"golang.org/x/net/context"
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// Backends need to be imported for their init() to get executed and them to register
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_ "github.com/flannel-io/flannel/backend/extension"
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_ "github.com/flannel-io/flannel/backend/hostgw"
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_ "github.com/flannel-io/flannel/backend/ipsec"
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_ "github.com/flannel-io/flannel/backend/vxlan"
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_ "github.com/flannel-io/flannel/backend/wireguard"
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)
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const (
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subnetFile = "/run/flannel/subnet.env"
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)
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func flannel(ctx context.Context, flannelIface *net.Interface, flannelConf, kubeConfigFile string, flannelIPv6Masq bool, netMode int) error {
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extIface, err := LookupExtInterface(flannelIface, netMode)
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if err != nil {
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return err
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}
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sm, err := kube.NewSubnetManager(ctx, "", kubeConfigFile, "flannel.alpha.coreos.com", flannelConf, false)
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if err != nil {
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return err
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}
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config, err := sm.GetNetworkConfig(ctx)
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if err != nil {
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return err
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}
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// Create a backend manager then use it to create the backend and register the network with it.
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bm := backend.NewManager(ctx, sm, extIface)
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be, err := bm.GetBackend(config.BackendType)
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if err != nil {
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return err
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}
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bn, err := be.RegisterNetwork(ctx, &sync.WaitGroup{}, config)
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if err != nil {
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return err
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}
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if netMode == (ipv4+ipv6) || netMode == ipv4 {
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go network.SetupAndEnsureIPTables(network.MasqRules(config.Network, bn.Lease()), 60)
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go network.SetupAndEnsureIPTables(network.ForwardRules(config.Network.String()), 50)
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}
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if flannelIPv6Masq && config.IPv6Network.String() != emptyIPv6Network {
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logrus.Debugf("Creating IPv6 masquerading iptables rules for %s network", config.IPv6Network.String())
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go network.SetupAndEnsureIP6Tables(network.MasqIP6Rules(config.IPv6Network, bn.Lease()), 60)
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go network.SetupAndEnsureIP6Tables(network.ForwardRules(config.IPv6Network.String()), 50)
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}
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if err := WriteSubnetFile(subnetFile, config.Network, config.IPv6Network, true, bn, netMode); err != nil {
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// Continue, even though it failed.
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logrus.Warningf("Failed to write flannel subnet file: %s", err)
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} else {
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logrus.Infof("Wrote flannel subnet file to %s", subnetFile)
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}
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// Start "Running" the backend network. This will block until the context is done so run in another goroutine.
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logrus.Info("Running flannel backend.")
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bn.Run(ctx)
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return nil
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}
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func LookupExtInterface(iface *net.Interface, netMode int) (*backend.ExternalInterface, error) {
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var ifaceAddr []net.IP
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var ifacev6Addr []net.IP
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var err error
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if iface == nil {
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logrus.Debug("No interface defined for flannel in the config. Fetching the default gateway interface")
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if netMode == ipv4 || netMode == (ipv4+ipv6) {
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if iface, err = ip.GetDefaultGatewayInterface(); err != nil {
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return nil, fmt.Errorf("failed to get default interface: %s", err)
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}
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} else {
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if iface, err = ip.GetDefaultV6GatewayInterface(); err != nil {
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return nil, fmt.Errorf("failed to get default interface: %s", err)
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}
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}
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}
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logrus.Debugf("The interface %s will be used by flannel", iface.Name)
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switch netMode {
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case ipv4:
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ifaceAddr, err = ip.GetInterfaceIP4Addrs(iface)
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if err != nil {
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return nil, fmt.Errorf("failed to find IPv4 address for interface %s", iface.Name)
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}
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logrus.Infof("The interface %s with ipv4 address %s will be used by flannel", iface.Name, ifaceAddr[0])
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ifacev6Addr = append(ifacev6Addr, nil)
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case ipv6:
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ifacev6Addr, err = ip.GetInterfaceIP6Addrs(iface)
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if err != nil {
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return nil, fmt.Errorf("failed to find IPv6 address for interface %s", iface.Name)
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}
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logrus.Infof("The interface %s with ipv6 address %s will be used by flannel", iface.Name, ifacev6Addr[0])
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ifaceAddr = append(ifaceAddr, nil)
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case (ipv4 + ipv6):
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ifaceAddr, err = ip.GetInterfaceIP4Addrs(iface)
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if err != nil {
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return nil, fmt.Errorf("failed to find IPv4 address for interface %s", iface.Name)
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}
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logrus.Infof("The interface %s with ipv4 address %s will be used by flannel", iface.Name, ifaceAddr[0])
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ifacev6Addr, err = ip.GetInterfaceIP6Addrs(iface)
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if err != nil {
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return nil, fmt.Errorf("failed to find IPv6 address for interface %s", iface.Name)
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}
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logrus.Infof("Using dual-stack mode. The ipv6 address %s will be used by flannel", ifacev6Addr[0])
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default:
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ifaceAddr = append(ifaceAddr, nil)
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ifacev6Addr = append(ifacev6Addr, nil)
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}
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if iface.MTU == 0 {
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return nil, fmt.Errorf("failed to determine MTU for %s interface", iface.Name)
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}
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return &backend.ExternalInterface{
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Iface: iface,
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IfaceAddr: ifaceAddr[0],
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IfaceV6Addr: ifacev6Addr[0],
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ExtAddr: ifaceAddr[0],
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ExtV6Addr: ifacev6Addr[0],
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}, nil
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}
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func WriteSubnetFile(path string, nw ip.IP4Net, nwv6 ip.IP6Net, ipMasq bool, bn backend.Network, netMode int) error {
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dir, name := filepath.Split(path)
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os.MkdirAll(dir, 0755)
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tempFile := filepath.Join(dir, "."+name)
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f, err := os.Create(tempFile)
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if err != nil {
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return err
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}
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// Write out the first usable IP by incrementing
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// sn.IP by one
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sn := bn.Lease().Subnet
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sn.IP++
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if netMode == ipv4 || netMode == (ipv4+ipv6) {
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fmt.Fprintf(f, "FLANNEL_NETWORK=%s\n", nw)
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fmt.Fprintf(f, "FLANNEL_SUBNET=%s\n", sn)
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}
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if nwv6.String() != emptyIPv6Network {
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snv6 := bn.Lease().IPv6Subnet
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snv6.IncrementIP()
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fmt.Fprintf(f, "FLANNEL_IPV6_NETWORK=%s\n", nwv6)
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fmt.Fprintf(f, "FLANNEL_IPV6_SUBNET=%s\n", snv6)
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}
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fmt.Fprintf(f, "FLANNEL_MTU=%d\n", bn.MTU())
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_, err = fmt.Fprintf(f, "FLANNEL_IPMASQ=%v\n", ipMasq)
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f.Close()
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if err != nil {
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return err
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}
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// rename(2) the temporary file to the desired location so that it becomes
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// atomically visible with the contents
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return os.Rename(tempFile, path)
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//TODO - is this safe? What if it's not on the same FS?
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}
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