add dynamic IP attributions

dhcp.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"errors"
+)
+
+func (s *OpenVpnMgt) isFree(ip string) bool {
+	for _, remote := range s.clients {
+		for _, c := range remote {
+			if c.PrivIP == ip {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// internal DHCP
+func (s *OpenVpnMgt) getIP(c *vpnSession) (string, error) {
+	s.m.Lock()
+	defer s.m.Unlock()
+
+	ipmax := nextIP(s.ldap[c.Profile].ipMax).String()
+
+	sip := s.ldap[c.Profile].ipMin.String()
+	for ip := s.ldap[c.Profile].ipMin; sip != ipmax; ip = nextIP(ip) {
+		sip = ip.String()
+		if s.isFree(sip) {
+			return sip, nil
+		}
+	}
+
+	return "", errors.New("no more IP")
+}