func cmdDel()

in cmd/egress-v4-cni-plugin/cni.go [343:420]
56 lines of code
16 McCabe index (conditional complexity)

func cmdDel(args *skel.CmdArgs) error {
	netConf, log, err := loadConf(args.StdinData)
	if err != nil {
		return fmt.Errorf("failed to parse config: %v", err)
	}

	//We only need this plugin to kick in if v6 is enabled
	if netConf.Enabled == "false" {
		return nil
	}

	log.Debugf("Received Del Request: conf=%v", netConf)
	if err := ipam.ExecDel(netConf.IPAM.Type, args.StdinData); err != nil {
		log.Debugf("running IPAM plugin failed: %v", err)
		return fmt.Errorf("running IPAM plugin failed: %v", err)
	}

	ipnets := []*net.IPNet{}
	if args.Netns != "" {
		err := ns.WithNetNSPath(args.Netns, func(hostNS ns.NetNS) error {
			var err error

			// DelLinkByNameAddr function deletes an interface and returns IPs assigned to it but it
			// excludes IPs that are not global unicast addresses (or) private IPs. Will not work for
			// our scenario as we use 169.254.0.0/16 range for v4 IPs.

			//Get the interface we want to delete
			iface, err := netlink.LinkByName(netConf.IfName)

			if err != nil {
				if _, ok := err.(netlink.LinkNotFoundError); ok {
					return nil
				}
				return nil
			}

			//Retrieve IP addresses assigned to the interface
			addrs, err := netlink.AddrList(iface, netlink.FAMILY_V4)
			if err != nil {
				return fmt.Errorf("failed to get IP addresses for %q: %v", netConf.IfName, err)
			}

			//Delete the interface/link.
			if err = netlink.LinkDel(iface); err != nil {
				return fmt.Errorf("failed to delete %q: %v", netConf.IfName, err)
			}

			for _, addr := range addrs {
				ipnets = append(ipnets, addr.IPNet)
			}

			if err != nil && err == ip.ErrLinkNotFound {
				log.Debugf("DEL: Link Not Found, returning", err)
				return nil
			}
			return err
		})

		//DEL should be best effort. We should clean up as much as we can and avoid returning error
		if err != nil {
			log.Debugf("DEL: Executing in container ns errored out, returning", err)
		}
	}

	chain := utils.MustFormatChainNameWithPrefix(netConf.Name, args.ContainerID, "E4-")
	comment := utils.FormatComment(netConf.Name, args.ContainerID)

	if netConf.NodeIP != nil {
		log.Debugf("DEL: SNAT setup, let's clean them up. Size of ipnets: %d", len(ipnets))
		for _, ipn := range ipnets {
			if err := snat.Snat4Del(ipn.IP, chain, comment); err != nil {
				return err
			}
		}
	}

	return nil
}