CNI net plugin

.gitmodules

@@ -67,3 +67,6 @@
 [submodule "vendor/github.com/appc/cni"]
 	path = vendor/github.com/appc/cni
 	url = https://github.com/appc/cni
+[submodule "vendor/github.com/coreos/go-iptables"]
+	path = vendor/github.com/coreos/go-iptables
+	url = https://github.com/coreos/go-iptables

plugin/net/cni.go

@@ -0,0 +1,158 @@
+package plugin
+
+import (
+	"crypto/rand"
+	"encoding/json"
+	"fmt"
+
+	"github.com/appc/cni/pkg/ipam"
+	"github.com/appc/cni/pkg/skel"
+	"github.com/appc/cni/pkg/types"
+	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netns"
+	weaveapi "github.com/weaveworks/weave/api"
+	"github.com/weaveworks/weave/common"
+	ipamplugin "github.com/weaveworks/weave/plugin/ipam"
+)
+
+type CNIPlugin struct {
+	weave *weaveapi.Client
+}
+
+func NewCNIPlugin(weave *weaveapi.Client) *CNIPlugin {
+	return &CNIPlugin{weave: weave}
+}
+
+func loadNetConf(bytes []byte) (*NetConf, error) {
+	n := &NetConf{
+		BrName: "weave",
+	}
+	if err := json.Unmarshal(bytes, n); err != nil {
+		return nil, errorf("failed to load netconf: %v", err)
+	}
+	return n, nil
+}
+
+func (c *CNIPlugin) CmdAdd(args *skel.CmdArgs) error {
+	conf, err := loadNetConf(args.StdinData)
+	if err != nil {
+		return err
+	}
+
+	if conf.IsGW {
+		return errorf("Gateway functionality not supported")
+	}
+	if conf.IPMasq {
+		return errorf("IP Masquerading functionality not supported")
+	}
+
+	ns, err := netns.GetFromPath(args.Netns)
+	if err != nil {
+		return err
+	}
+	defer ns.Close()
+
+	id := args.ContainerID
+	if len(id) < 5 {
+		data := make([]byte, 5)
+		_, err := rand.Reader.Read(data)
+		if err != nil {
+			return err
+		}
+		id = fmt.Sprintf("%x", data)
+	}
+
+	local, err := createAndAttach(id, conf.BrName, conf.MTU)
+	if err != nil {
+		return err
+	}
+
+	cleanup := func(err error) error {
+		netlink.LinkDel(local)
+		return err
+	}
+	guest, err := netlink.LinkByName(local.PeerName)
+	if err != nil {
+		return cleanup(err)
+	}
+	if err = netlink.LinkSetNsFd(guest, int(ns)); err != nil {
+		return cleanup(errorf("failed to move veth to container netns: %s", err))
+	}
+
+	if err := netlink.LinkSetUp(local); err != nil {
+		return cleanup(errorf("unable to bring veth up: %s", err))
+	}
+
+	var result *types.Result
+	// Default IPAM is Weave's own
+	if conf.IPAM.Type == "" {
+		result, err = ipamplugin.NewIpam(c.weave).Allocate(args)
+	} else {
+		result, err = ipam.ExecAdd(conf.IPAM.Type, args.StdinData)
+	}
+	if err != nil {
+		return cleanup(errorf("unable to allocate IP address: %s", err))
+	}
+	if result.IP4 == nil {
+		return cleanup(errorf("IPAM plugin failed to allocate IP address"))
+	}
+
+	err = common.WithNetNS(ns, func() error {
+		guest, err := netlink.LinkByName(local.PeerName)
+		if err != nil {
+			return cleanup(err)
+		}
+		if err = netlink.LinkSetName(guest, args.IfName); err != nil {
+			return err
+		}
+		return ipam.ConfigureIface(args.IfName, result)
+	})
+	if err != nil {
+		return cleanup(errorf("error setting up interface: %s", err))
+	}
+
+	result.DNS = conf.DNS
+	return result.Print()
+}
+
+func (c *CNIPlugin) CmdDel(args *skel.CmdArgs) error {
+	conf, err := loadNetConf(args.StdinData)
+	if err != nil {
+		return err
+	}
+
+	ns, err := netns.GetFromPath(args.Netns)
+	if err != nil {
+		return err
+	}
+	defer ns.Close()
+	err = common.WithNetNS(ns, func() error {
+		link, err := netlink.LinkByName(args.IfName)
+		if err != nil {
+			return err
+		}
+		return netlink.LinkDel(link)
+	})
+	if err != nil {
+		return errorf("error removing interface: %s", err)
+	}
+
+	// Default IPAM is Weave's own
+	if conf.IPAM.Type == "" {
+		err = ipamplugin.NewIpam(c.weave).Release(args)
+	} else {
+		err = ipam.ExecDel(conf.IPAM.Type, args.StdinData)
+	}
+	if err != nil {
+		return errorf("unable to release IP address: %s", err)
+	}
+	return nil
+}
+
+type NetConf struct {
+	types.NetConf
+	BrName string `json:"bridge"`
+	IsGW   bool   `json:"isGateway"`
+	IPMasq bool   `json:"ipMasq"`
+	MTU    int    `json:"mtu"`
+}

prog/plugin/main.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strings"
 	"syscall"
 
 	cni "github.com/appc/cni/pkg/skel"
@@ -48,10 +49,15 @@ func main() {
 
 	weave := weaveapi.NewClient(os.Getenv("WEAVE_HTTP_ADDR"), Log)
 
-	if os.Args[0] == "weave-ipam" {
+	switch {
+	case strings.HasSuffix(os.Args[0], "weave-ipam"):
 		i := ipamplugin.NewIpam(weave)
 		cni.PluginMain(i.CmdAdd, i.CmdDel)
 		os.Exit(0)
+	case strings.HasSuffix(os.Args[0], "weave"):
+		n := netplugin.NewCNIPlugin(weave)
+		cni.PluginMain(n.CmdAdd, n.CmdDel)
+		os.Exit(0)
 	}
 
 	// API 1.21 is the first version that supports docker network commands