initial commit

pkg/vip/vip.go

@@ -0,0 +1,142 @@
+package vip
+
+import (
+	"sync"
+
+	"github.com/pkg/errors"
+	"github.com/vishvananda/netlink"
+)
+
+const (
+	defaultValidLft = 60
+)
+
+// Network is an interface that enable managing operations for a given IP
+type Network interface {
+	AddIP() error
+	DeleteIP() error
+	IsSet() (bool, error)
+	IP() string
+	SetIP(ip string) error
+	Interface() string
+}
+
+// network - This allows network configuration
+type network struct {
+	mu sync.Mutex
+
+	address *netlink.Addr
+	link    netlink.Link
+	isDNS   bool
+}
+
+// NewConfig will attempt to provide an interface to the kernel network configuration
+func NewConfig(address string, iface string) (Network, error) {
+	result := &network{}
+
+	link, err := netlink.LinkByName(iface)
+	if err != nil {
+		return result, errors.Wrapf(err, "could not get link for interface '%s'", iface)
+	}
+	result.link = link
+
+	if IsIP(address) {
+		result.address, err = netlink.ParseAddr(address + "/32")
+		if err != nil {
+			return result, errors.Wrapf(err, "could not parse address '%s'", address)
+		}
+		return result, nil
+	}
+
+	// try to resolve the address
+	ip, err := lookupHost(address)
+	result.isDNS = err == nil
+	if err != nil {
+		return nil, err
+	}
+
+	// we're able to resolve store this as the initial IP
+	if result.address, err = netlink.ParseAddr(ip + "/32"); err != nil {
+		return result, err
+	}
+	// set ValidLft so that the VIP expires if the DNS entry is updated, otherwise it'll be refreshed by the DNS prober
+	result.address.ValidLft = defaultValidLft
+
+	return result, err
+}
+
+//AddIP - Add an IP address to the interface
+func (configurator *network) AddIP() error {
+	if err := netlink.AddrReplace(configurator.link, configurator.address); err != nil {
+		return errors.Wrap(err, "could not add ip")
+	}
+	return nil
+}
+
+//DeleteIP - Remove an IP address from the interface
+func (configurator *network) DeleteIP() error {
+	result, err := configurator.IsSet()
+	if err != nil {
+		return errors.Wrap(err, "ip check in DeleteIP failed")
+	}
+
+	// Nothing to delete
+	if !result {
+		return nil
+	}
+
+	if err = netlink.AddrDel(configurator.link, configurator.address); err != nil {
+		return errors.Wrap(err, "could not delete ip")
+	}
+
+	return nil
+}
+
+// IsSet - Check to see if VIP is set
+func (configurator *network) IsSet() (result bool, err error) {
+	var addresses []netlink.Addr
+
+	addresses, err = netlink.AddrList(configurator.link, 0)
+	if err != nil {
+		err = errors.Wrap(err, "could not list addresses")
+
+		return
+	}
+
+	for _, address := range addresses {
+		if address.Equal(*configurator.address) {
+			return true, nil
+		}
+	}
+
+	return false, nil
+}
+
+// SetIP updates the IP that is used
+func (configurator *network) SetIP(ip string) error {
+	configurator.mu.Lock()
+	defer configurator.mu.Unlock()
+
+	addr, err := netlink.ParseAddr(ip + "/32")
+	if err != nil {
+		return err
+	}
+	if configurator.address != nil && configurator.isDNS {
+		addr.ValidLft = defaultValidLft
+	}
+	configurator.address = addr
+	return nil
+}
+
+// IP - return the IP Address
+func (configurator *network) IP() string {
+	configurator.mu.Lock()
+	defer configurator.mu.Unlock()
+
+	return configurator.address.IP.String()
+}
+
+// Interface - return the Interface name
+func (configurator *network) Interface() string {
+	return configurator.link.Attrs().Name
+}