add endpoints for ipblocks/containers

This also adds a view to get a list of all containers and their free
space in between.
This is needed for ippool_list to get a nice overview over everything.

The code of the function is based on
https://pkg.go.dev/inet.af/netaddr#IPRange.Prefixes

Many thanks to Brad Fitzpatrick for the awesome code and changelog to
make it possible to understand what is going on.

main.go

@@ -68,7 +68,11 @@ func main() {
 	s.Register("layer3domain_list", layer3DomainList)
 	s.Register("layer3domain_get_attr", layer3DomainGetAttr)
 	s.Register("layer3domain_set_attr", layer3DomainSetAttr)
-	s.Register("ipblock_create", ipblockCreate)
+	s.Register("ipblock_create", containerCreate)
+	s.Register("ipblock_remove", containerDelete)
+	s.Register("ipblock_list", containerList)
+	s.Register("ipblock_set_attr", containerSetAttr)
+	s.Register("ipblock_get_attr", containerGetAttr)
 	s.Register("ippool_create", PoolCreate)
 	s.Register("ippool_delete", PoolDelete)
 	s.Register("ippool_list", PoolList)

types/ip.go

@@ -5,6 +5,7 @@ import (
 	"database/sql/driver"
 	"fmt"
 	"net"
+	"strconv"
 )
 
 type (
@@ -12,6 +13,8 @@ type (
 	Subnet net.IPNet
 	// IP is used to parse an IP parameter.
 	IP net.IP
+	// IPVersion represents the two IP versions currently in use.
+	IPVersion int
 )
 
 // UnmarshalJSON parses a value into a subnet.
@@ -69,3 +72,16 @@ func (i *IP) UnmarshalJSON(in []byte) error {
 	*i = IP(ip)
 	return nil
 }
+
+// UnmarshalJSON parses the incoming version from json.
+func (v *IPVersion) UnmarshalJSON(in []byte) error {
+	raw, err := strconv.Atoi(string(in))
+	if err != nil {
+		return fmt.Errorf("can't parse ip version: %#v", err)
+	}
+	if raw != 4 && raw != 6 {
+		return fmt.Errorf("only version 4 and 6 are supported")
+	}
+	*v = IPVersion(raw)
+	return nil
+}