AdGuardHome/internal/dhcpsvc/interface.go

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package dhcpsvc
import (
"fmt"
"slices"
"time"
)
// netInterface is a common part of any network interface within the DHCP
// server.
//
// TODO(e.burkov): Add other methods as [DHCPServer] evolves.
type netInterface struct {
// name is the name of the network interface.
name string
// leases is a set of leases sorted by hardware address.
leases []*Lease
// leaseTTL is the default Time-To-Live value for leases.
leaseTTL time.Duration
}
// reset clears all the slices in iface for reuse.
func (iface *netInterface) reset() {
iface.leases = iface.leases[:0]
}
// insertLease inserts the given lease into iface. It returns an error if the
// lease can't be inserted.
func (iface *netInterface) insertLease(l *Lease) (err error) {
i, found := slices.BinarySearchFunc(iface.leases, l, compareLeaseMAC)
if found {
return fmt.Errorf("lease for mac %s already exists", l.HWAddr)
}
iface.leases = slices.Insert(iface.leases, i, l)
return nil
}
// updateLease replaces an existing lease within iface with the given one. It
// returns an error if there is no lease with such hardware address.
func (iface *netInterface) updateLease(l *Lease) (prev *Lease, err error) {
i, found := slices.BinarySearchFunc(iface.leases, l, compareLeaseMAC)
if !found {
return nil, fmt.Errorf("no lease for mac %s", l.HWAddr)
}
prev, iface.leases[i] = iface.leases[i], l
return prev, nil
}
// removeLease removes an existing lease from iface. It returns an error if
// there is no lease equal to l.
func (iface *netInterface) removeLease(l *Lease) (err error) {
i, found := slices.BinarySearchFunc(iface.leases, l, compareLeaseMAC)
if !found {
return fmt.Errorf("no lease for mac %s", l.HWAddr)
}
iface.leases = slices.Delete(iface.leases, i, i+1)
return nil
}