added auth method

pkg/alloc/alloc.go

@@ -0,0 +1,112 @@
+package alloc
+
+import (
+	"context"
+	"fmt"
+	"net"
+
+	"git.giftfish.de/ston1th/haproxy-lb/pkg/cluster"
+	"github.com/mikioh/ipaddr"
+)
+
+type Alloc struct {
+	kv      cluster.KV
+	pool    []*net.IPNet
+	gateway *net.IPNet
+}
+
+func NewAlloc(kv cluster.KV, cidrs []string, gateway string) (*Alloc, error) {
+	pool, err := parseRange(cidrs)
+	if err != nil {
+		return nil, err
+	}
+	_, gw, err := net.ParseCIDR(gateway)
+	if err != nil {
+		return nil, err
+	}
+	return &Alloc{kv, pool, gw}, nil
+}
+
+func (a *Alloc) AllocIP(ctx context.Context, name string) (addr string, err error) {
+	for _, cidr := range a.pool {
+		c := ipaddr.NewCursor([]ipaddr.Prefix{*ipaddr.NewPrefix(a.gateway)})
+		for pos := c.First(); pos != nil; pos = c.Next() {
+			ip := pos.IP.String()
+			v, _ := a.kv.Get(ip)
+			vs := string(v)
+			if v == "" {
+				err = a.kv.Set(ip, []byte(name))
+				if err != nil {
+					return
+				}
+				err = a.kv.Set(name, []byte(ip))
+				if err != nil {
+					a.kv.Delete(ip)
+					return
+				}
+				var gw *net.IPNet
+				*gw = *a.gateway
+				gw.IP = pos.IP
+				addr = gw.String()
+				return
+			}
+		}
+	}
+	err = fmt.Errorf("no available IPs in pool")
+	return
+}
+
+func (a *Alloc) FreeIP(ctx context.Context, name string) (err error) {
+	if name == "" {
+		return
+	}
+	v, err := a.kv.Get(name)
+	if err != nil {
+		return
+	}
+	vs := string(v)
+	err = a.kv.Delete(vs)
+	if err != nil {
+		return
+	}
+	err = a.kv.Delete(name)
+	if err != nil {
+		a.kv.Set(vs, []byte(name))
+	}
+	return
+}
+
+func parseRange(cidrs []string) (nets []*net.IPNet, err error) {
+	for _, cidr := range cidrs {
+		if !strings.Contains(cidr, "-") {
+			_, n, err := net.ParseCIDR(cidr)
+			if err != nil {
+				return nil, err
+			}
+			nets = append(nets, n)
+			continue
+		}
+
+		fs := strings.SplitN(cidr, "-", 2)
+		if len(fs) != 2 {
+			return nil, fmt.Errorf("invalid IP range %q", cidr)
+		}
+		start := net.ParseIP(strings.TrimSpace(fs[0]))
+		if start == nil {
+			return nil, fmt.Errorf("invalid IP range %q: invalid start IP %q", cidr, fs[0])
+		}
+		end := net.ParseIP(strings.TrimSpace(fs[1]))
+		if end == nil {
+			return nil, fmt.Errorf("invalid IP range %q: invalid end IP %q", cidr, fs[1])
+		}
+
+		for _, pfx := range ipaddr.Summarize(start, end) {
+			n := &net.IPNet{
+				IP:   pfx.IP,
+				Mask: pfx.Mask,
+			}
+			nets = append(nets, n)
+		}
+	}
+	return
+}