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package xt
import (
"errors"
"net"
"github.com/google/nftables/alignedbuff"
)
// See https://elixir.bootlin.com/linux/v5.17.7/source/include/uapi/linux/netfilter/nf_nat.h#L25
type NatIPv4Range struct {
Flags uint // sic!
MinIP net.IP
MaxIP net.IP
MinPort uint16
MaxPort uint16
}
// NatIPv4MultiRangeCompat despite being a slice of NAT IPv4 ranges is currently allowed to
// only hold exactly one element.
//
// See https://elixir.bootlin.com/linux/v5.17.7/source/include/uapi/linux/netfilter/nf_nat.h#L33
type NatIPv4MultiRangeCompat []NatIPv4Range
func (x *NatIPv4MultiRangeCompat) marshal(fam TableFamily, rev uint32) ([]byte, error) {
ab := alignedbuff.New()
if len(*x) != 1 {
return nil, errors.New("MasqueradeIp must contain exactly one NatIPv4Range")
}
ab.PutUint(uint(len(*x)))
for _, nat := range *x {
if err := nat.marshalAB(fam, rev, &ab); err != nil {
return nil, err
}
}
return ab.Data(), nil
}
func (x *NatIPv4MultiRangeCompat) unmarshal(fam TableFamily, rev uint32, data []byte) error {
ab := alignedbuff.NewWithData(data)
l, err := ab.Uint()
if err != nil {
return err
}
nats := make(NatIPv4MultiRangeCompat, l)
for l > 0 {
l--
if err := nats[l].unmarshalAB(fam, rev, &ab); err != nil {
return err
}
}
*x = nats
return nil
}
func (x *NatIPv4Range) marshalAB(fam TableFamily, rev uint32, ab *alignedbuff.AlignedBuff) error {
ab.PutUint(x.Flags)
ab.PutBytesAligned32(x.MinIP.To4(), 4)
ab.PutBytesAligned32(x.MaxIP.To4(), 4)
ab.PutUint16BE(x.MinPort)
ab.PutUint16BE(x.MaxPort)
return nil
}
func (x *NatIPv4Range) unmarshalAB(fam TableFamily, rev uint32, ab *alignedbuff.AlignedBuff) error {
var err error
if x.Flags, err = ab.Uint(); err != nil {
return err
}
var ip []byte
if ip, err = ab.BytesAligned32(4); err != nil {
return err
}
x.MinIP = net.IP(ip)
if ip, err = ab.BytesAligned32(4); err != nil {
return err
}
x.MaxIP = net.IP(ip)
if x.MinPort, err = ab.Uint16BE(); err != nil {
return err
}
if x.MaxPort, err = ab.Uint16BE(); err != nil {
return err
}
return nil
}
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