105 lines
2.6 KiB
Go
105 lines
2.6 KiB
Go
package dhcpsvc
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import (
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"fmt"
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"log/slog"
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"net"
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"time"
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)
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// macKey contains hardware address as byte array of 6, 8, or 20 bytes.
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//
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// TODO(e.burkov): Move to aghnet or even to netutil.
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type macKey any
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// macToKey converts mac into macKey, which is used as the key for the lease
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// maps. mac must be a valid hardware address of length 6, 8, or 20 bytes, see
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// [netutil.ValidateMAC].
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func macToKey(mac net.HardwareAddr) (key macKey) {
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switch len(mac) {
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case 6:
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return [6]byte(mac)
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case 8:
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return [8]byte(mac)
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case 20:
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return [20]byte(mac)
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default:
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panic(fmt.Errorf("invalid mac address %#v", mac))
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}
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}
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// netInterface is a common part of any interface within the DHCP server.
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//
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// TODO(e.burkov): Add other methods as [DHCPServer] evolves.
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type netInterface struct {
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// logger logs the events related to the network interface.
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logger *slog.Logger
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// leases is the set of DHCP leases assigned to this interface.
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leases map[macKey]*Lease
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// name is the name of the network interface.
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name string
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// leaseTTL is the default Time-To-Live value for leases.
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leaseTTL time.Duration
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}
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// newNetInterface creates a new netInterface with the given name, leaseTTL, and
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// logger.
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func newNetInterface(name string, l *slog.Logger, leaseTTL time.Duration) (iface *netInterface) {
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return &netInterface{
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logger: l,
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leases: map[macKey]*Lease{},
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name: name,
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leaseTTL: leaseTTL,
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}
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}
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// reset clears all the slices in iface for reuse.
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func (iface *netInterface) reset() {
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clear(iface.leases)
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}
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// addLease inserts the given lease into iface. It returns an error if the
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// lease can't be inserted.
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func (iface *netInterface) addLease(l *Lease) (err error) {
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mk := macToKey(l.HWAddr)
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_, found := iface.leases[mk]
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if found {
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return fmt.Errorf("lease for mac %s already exists", l.HWAddr)
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}
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iface.leases[mk] = l
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return nil
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}
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// updateLease replaces an existing lease within iface with the given one. It
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// returns an error if there is no lease with such hardware address.
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func (iface *netInterface) updateLease(l *Lease) (prev *Lease, err error) {
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mk := macToKey(l.HWAddr)
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prev, found := iface.leases[mk]
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if !found {
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return nil, fmt.Errorf("no lease for mac %s", l.HWAddr)
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}
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iface.leases[mk] = l
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return prev, nil
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}
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// removeLease removes an existing lease from iface. It returns an error if
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// there is no lease equal to l.
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func (iface *netInterface) removeLease(l *Lease) (err error) {
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mk := macToKey(l.HWAddr)
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_, found := iface.leases[mk]
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if !found {
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return fmt.Errorf("no lease for mac %s", l.HWAddr)
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}
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delete(iface.leases, mk)
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return nil
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}
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