dotcloud/docker

// Package null implements the null ipam driver. Null ipam driver satisfies ipamapi contract,
// but does not effectively reserve/allocate any address pool or address
package null

import (
    "net"
    "net/netip"

    "github.com/docker/docker/libnetwork/ipamapi"
    "github.com/docker/docker/libnetwork/types"
)

const (
    // DriverName is the name of the built-in null ipam driver
    DriverName = "null"

    defaultAddressSpace = "null"
    defaultPoolCIDR4    = "0.0.0.0/0"
    defaultPoolID4      = defaultAddressSpace + "/" + defaultPoolCIDR4
    defaultPoolCIDR6    = "::/0"
    defaultPoolID6      = defaultAddressSpace + "/" + defaultPoolCIDR6
)

var defaultPool4 = netip.MustParsePrefix(defaultPoolCIDR4)
var defaultPool6 = netip.MustParsePrefix(defaultPoolCIDR6)

type allocator struct{}

func (a *allocator) GetDefaultAddressSpaces() (string, string, error) {
    return defaultAddressSpace, defaultAddressSpace, nil
}

func (a *allocator) RequestPool(req ipamapi.PoolRequest) (ipamapi.AllocatedPool, error) {
    if req.AddressSpace != defaultAddressSpace {
        return ipamapi.AllocatedPool{}, types.InvalidParameterErrorf("unknown address space: %s", req.AddressSpace)
    }
    if req.Pool != "" {
        return ipamapi.AllocatedPool{}, types.InvalidParameterErrorf("null ipam driver does not handle specific address pool requests")
    }
    if req.SubPool != "" {
        return ipamapi.AllocatedPool{}, types.InvalidParameterErrorf("null ipam driver does not handle specific address subpool requests")
    }
    if req.V6 {
        return ipamapi.AllocatedPool{
            PoolID: defaultPoolID6,
            Pool:   defaultPool6,
        }, nil
    }
    return ipamapi.AllocatedPool{
        PoolID: defaultPoolID4,
        Pool:   defaultPool4,
    }, nil
}

func (a *allocator) ReleasePool(poolID string) error {
    return nil
}

func (a *allocator) RequestAddress(poolID string, ip net.IP, opts map[string]string) (*net.IPNet, map[string]string, error) {
    if poolID != defaultPoolID4 && poolID != defaultPoolID6 {
        return nil, nil, types.InvalidParameterErrorf("unknown pool id: %s", poolID)
    }
    return nil, nil, nil
}

func (a *allocator) ReleaseAddress(poolID string, ip net.IP) error {
    if poolID != defaultPoolID4 && poolID != defaultPoolID6 {
        return types.InvalidParameterErrorf("unknown pool id: %s", poolID)
    }
    return nil
}

func (a *allocator) IsBuiltIn() bool {
    return true
}

// Register registers the null ipam driver with r.
func Register(r ipamapi.Registerer) error {
    return r.RegisterIpamDriver(DriverName, &allocator{})
}