Ensure unique veth name and myc ip per container

main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"net"
@@ -14,7 +16,7 @@ import (
 )
 
 const (
-	PluginName = "mycelium-cni"
+	PluginName        = "mycelium-cni"
 	MyceliumInterface = "mycelium"
 )
 
@@ -46,8 +48,8 @@ func cmdAdd(args *skel.CmdArgs) error {
 		return fmt.Errorf("failed to get Mycelium IP: %v", err)
 	}
 
-	// Create veth pair
-	hostVethName := fmt.Sprintf("veth-%s", args.ContainerID[:8])
+	// Create veth pair with unique naming
+	hostVethName := generateVethName(args.ContainerID)
 	containerVethName := "eth0"
 
 	hostVeth, containerVeth, err := createVethPair(hostVethName, containerVethName)
@@ -101,8 +103,8 @@ func cmdCheck(args *skel.CmdArgs) error {
 
 func cmdDel(args *skel.CmdArgs) error {
 	// Clean up veth pair (host side will be automatically removed)
-	hostVethName := fmt.Sprintf("veth-%s", args.ContainerID[:8])
-	
+	hostVethName := generateVethName(args.ContainerID)
+
 	link, err := netlink.LinkByName(hostVethName)
 	if err != nil {
 		// Interface might already be gone, which is fine
@@ -146,14 +148,25 @@ func getMyceliumIP(interfaceName string) (net.IP, error) {
 }
 
 func generateContainerIP(myceliumPrefix net.IP, containerID string) net.IP {
-	// Generate a container IP within the /64 prefix
-	// Using simple approach: prefix + ::1 (could be made more sophisticated)
+	// Generate a unique container IP within the /64 prefix using container ID hash
+	hash := sha256.Sum256([]byte(containerID))
+	
 	containerIP := make(net.IP, len(myceliumPrefix))
 	copy(containerIP, myceliumPrefix)
-	containerIP[15] = 1 // Set last byte to 1
+	
+	// Use first 8 bytes of hash for the host part (last 64 bits)
+	copy(containerIP[8:], hash[:8])
+	
 	return containerIP
 }
 
+func generateVethName(containerID string) string {
+	// Generate unique but short veth name using hash of container ID
+	hash := sha256.Sum256([]byte(containerID))
+	shortHash := hex.EncodeToString(hash[:4]) // Use first 4 bytes for 8-char hex
+	return fmt.Sprintf("veth-%s", shortHash)
+}
+
 func createVethPair(hostName, containerName string) (netlink.Link, netlink.Link, error) {
 	veth := &netlink.Veth{
 		LinkAttrs: netlink.LinkAttrs{Name: hostName},
@@ -194,52 +207,73 @@ func configureContainerInterface(containerNS netns.NsHandle, ifName string, cont
 	if err := netns.Set(containerNS); err != nil {
 		return err
 	}
-		// Get the interface
-		link, err := netlink.LinkByName(ifName)
-		if err != nil {
-			return err
-		}
+	// Get the interface
+	link, err := netlink.LinkByName(ifName)
+	if err != nil {
+		return err
+	}
 
-		// Bring interface up
-		if err := netlink.LinkSetUp(link); err != nil {
-			return err
-		}
+	// Bring interface up
+	if err := netlink.LinkSetUp(link); err != nil {
+		return err
+	}
 
-		// Add IP address
-		addr := &netlink.Addr{
-			IPNet: &net.IPNet{
-				IP:   containerIP,
-				Mask: net.CIDRMask(64, 128),
+	// Add IP address
+	addr := &netlink.Addr{
+		IPNet: &net.IPNet{
+			IP:   containerIP,
+			Mask: net.CIDRMask(64, 128),
+		},
+	}
+	if err := netlink.AddrAdd(link, addr); err != nil {
+		return err
+	}
+
+	// Switch to main namespace to get host veth address
+	if err := netns.Set(originalNS); err != nil {
+		return err
+	}
+
+	// Get host veth link-local address
+	hostVeth, err := netlink.LinkByName(hostVethName)
+	if err != nil {
+		return err
+	}
+
+	hostAddrs, err := netlink.AddrList(hostVeth, netlink.FAMILY_V6)
+	if err != nil {
+		return err
+	}
+
+	var hostLLAddr net.IP
+	for _, addr := range hostAddrs {
+		if addr.IP.IsLinkLocalUnicast() {
+			hostLLAddr = addr.IP
+			break
+		}
+	}
+
+	// Switch back to container namespace to add route
+	if err := netns.Set(containerNS); err != nil {
+		return err
+	}
+
+	if hostLLAddr != nil {
+		// Add route to Mycelium network via host veth
+		route := &netlink.Route{
+			Dst: &net.IPNet{
+				IP:   net.ParseIP("400::"),
+				Mask: net.CIDRMask(7, 128),
 			},
+			Gw:        hostLLAddr,
+			LinkIndex: link.Attrs().Index,
 		}
-		if err := netlink.AddrAdd(link, addr); err != nil {
+		if err := netlink.RouteAdd(route); err != nil {
 			return err
 		}
+	}
 
-		// Get host veth link-local address for routing
-		hostVeth, err := netlink.LinkByName(hostVethName)
-		if err == nil {
-			hostAddrs, err := netlink.AddrList(hostVeth, netlink.FAMILY_V6)
-			if err == nil {
-				for _, addr := range hostAddrs {
-					if addr.IP.IsLinkLocalUnicast() {
-						// Add route to Mycelium network via host veth
-						route := &netlink.Route{
-							Dst: &net.IPNet{
-								IP:   net.ParseIP("400::"),
-								Mask: net.CIDRMask(7, 128),
-							},
-							Gw:        addr.IP,
-							LinkIndex: link.Attrs().Index,
-						}
-						netlink.RouteAdd(route)
-						break
-					}
-				}
-			}
-		}
-
-		return nil
+	return nil
 }
 
 func configureHostInterface(hostVeth netlink.Link, containerIP net.IP) error {