temporary fix for /32 CIDR networking issue

.travis.yml

@@ -7,7 +7,7 @@
 
 language: go
 go:
-  - 1.8.x
+  - 1.11.x
   - tip
 
 matrix:

Dockerfile.build

@@ -1,4 +1,4 @@
-FROM golang:1.9
+FROM golang:1.11
 RUN go get -u github.com/golang/dep/cmd/dep
 RUN apt update
 RUN apt install -y genisoimage

README.md

@@ -83,6 +83,9 @@ sudo docker run --rm --runtime=runnc nablact/nabla-node-base:latest
 
 There are many. Some are fixable and being worked on, some are fixable but harder and will take some time, and some others are ones that we don't really know how to fix (or possibly not worth fixing).
 
+Container runtime limitations:
+- Unable to properly handle /32 IP address assignments. Current hack converts cidr from 32 to 1
+
 Here are some missing features that we are currently working on:
 - a golang base image
 - MirageOS and IncludeOS base images

nabla-lib/network/network_linux.go

@@ -251,52 +251,53 @@ func CreateMacvtapInterfaceDocker(tapName *string, master string) (
 	return masterIP, gwAddr, masterMask, tapMac, nil
 }
 
-func getMasterDetails(masterLink netlink.Link) (masterAddr *netlink.Addr, masterIP net.IP, masterMask net.IPMask, gwAddr net.IP, err error) {
+func getMasterDetails(masterLink netlink.Link) (masterAddr *netlink.Addr, masterIP net.IP, masterMask net.IPMask, gwAddr net.IP, mac string, err error) {
 	addrs, err := netlink.AddrList(masterLink, netlink.FAMILY_V4)
 	if err != nil {
-		return nil, nil, nil, nil, err
+		return nil, nil, nil, nil, "", err
 	}
 	if len(addrs) == 0 {
-		return nil, nil, nil, nil, fmt.Errorf("master should have an IP")
+		return nil, nil, nil, nil, "", fmt.Errorf("master should have an IP")
 	}
 	masterAddr = &addrs[0]
 	masterIP = addrs[0].IPNet.IP
 	masterMask = addrs[0].IPNet.Mask
 
 	routes, err := netlink.RouteList(masterLink, netlink.FAMILY_V4)
 	if err != nil {
-		return nil, nil, nil, nil, err
+		return nil, nil, nil, nil, "", err
 	}
 	if len(routes) == 0 {
-		return nil, nil, nil, nil,
+		return nil, nil, nil, nil, "",
 			fmt.Errorf("master should have at least one route")
 	}
 	// XXX: is the "gateway" always the first route?
 	gwAddr = routes[0].Gw
 
-	return masterAddr, masterIP, masterMask, gwAddr, nil
+	macAddr := masterLink.Attrs().HardwareAddr.String()
+	return masterAddr, masterIP, masterMask, gwAddr, macAddr, nil
 }
 
 // CreateTapInterfaceDocker creates a new TAP interface and a bridge, adds both
 // the TAP and the master link (usually eth0) to the bridge, and unsets the IP
 // of the master link to be used by the unikernel NIC.  Returns the assigned
 // IP/mask and gateway IP.
 func CreateTapInterfaceDocker(tapName string, master string) (
-	net.IP, net.IP, net.IPMask, error) {
+	net.IP, net.IP, net.IPMask, string, error) {
 
 	masterLink, err := netlink.LinkByName(master)
 	if err != nil {
-		return nil, nil, nil,
+		return nil, nil, nil, "",
 			fmt.Errorf("no master interface: %v", err)
 	}
-	masterAddr, masterIP, masterMask, gwAddr, err := getMasterDetails(masterLink)
+	masterAddr, masterIP, masterMask, gwAddr, mac, err := getMasterDetails(masterLink)
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, nil, "", err
 	}
 
 	err = SetupTunDev()
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, nil, "", err
 	}
 
 	// ip tuntap add tap100 mode tap
@@ -305,24 +306,34 @@ func CreateTapInterfaceDocker(tapName string, master string) (
 		Mode:      netlink.TUNTAP_MODE_TAP}
 	err = netlink.LinkAdd(tap)
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, nil, "", err
 	}
 
 	// ip link set dev tap100 up'
 	err = netlink.LinkSetUp(tap)
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, nil, "", err
 	}
 
 	// ip addr del $INET_STR dev master
 	err = netlink.AddrDel(masterLink, masterAddr)
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, nil, "", err
+	}
+
+	genmac, err := net.ParseMAC("aa:aa:aa:aa:bb:cc")
+	if err != nil {
+		return nil, nil, nil, "", err
+	}
+
+	err = netlink.LinkSetHardwareAddr(masterLink, genmac)
+	if err != nil {
+		return nil, nil, nil, "", err
 	}
 
 	br0, err := CreateBridge("br0")
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, nil, "", err
 	}
 
 	netlink.LinkSetMaster(masterLink, br0)
@@ -331,10 +342,9 @@ func CreateTapInterfaceDocker(tapName string, master string) (
 	// ip link set dev br0 up'
 	err = netlink.LinkSetUp(br0)
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, nil, "", err
 	}
-
-	return masterIP, gwAddr, masterMask, nil
+	return masterIP, gwAddr, masterMask, mac, nil
 }
 
 // SetupTunDev sets up the /dev/net/tun device if it doesn't exists

runnc-cont/rumprun.go

@@ -105,13 +105,22 @@ func CreateRumprunArgs(ip net.IP, mask net.IPMask, gw net.IP,
 	mountPoint string, envVars []string, cwd string,
 	unikernel string, cmdargs string) (string, error) {
 
+	// XXX: Due to bug in: https://github.com/nabla-containers/runnc/issues/40
+	// If we detect a /32 mask, we set it to 1 as a "fix", and hope we are in
+	// the same subnet... (working on a fix for mask:0)
+	cidr := strconv.Itoa(network.MaskCIDR(mask))
+	if cidr == "32" {
+		fmt.Printf("WARNING: Changing CIDR from 32 to 1 due to Issue https://github.com/nabla-containers/runnc/issues/40\n")
+		cidr = "1"
+	}
+
 	net := rumpArgsNetwork{
 		If:     "ukvmif0",
 		Cloner: "True",
 		Type:   "inet",
 		Method: "static",
 		Addr:   ip.String(),
-		Mask:   strconv.Itoa(network.MaskCIDR(mask)),
+		Mask:   cidr,
 		Gw:     gw.String(),
 	}
 

runnc-cont/runnc_cont.go

@@ -142,7 +142,7 @@ func run(nablarun string, unikernel string, tapName string,
 		// container veth pair.
 		// XXX: This is a workaround due to an error with MacvTap, error was :
 		// Could not create /dev/tap8863: open /sys/devices/virtual/net/macvtap8863/tap8863/dev: no such file or directory
-		ip, gw, mask, err = network.CreateTapInterfaceDocker(tapName, "eth0")
+		ip, gw, mask, mac, err = network.CreateTapInterfaceDocker(tapName, "eth0")
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "Could not create %s: %v\n", tapName, err)
 			return 1