127 lines
3.3 KiB
Go
127 lines
3.3 KiB
Go
package dhcpsvc
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import (
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"fmt"
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"net/netip"
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"slices"
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"strings"
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)
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// leaseIndex is the set of leases indexed by their identifiers for quick
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// lookup.
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type leaseIndex struct {
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// byAddr is a lookup shortcut for leases by their IP addresses.
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byAddr map[netip.Addr]*Lease
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// byName is a lookup shortcut for leases by their hostnames.
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//
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// TODO(e.burkov): Use a slice of leases with the same hostname?
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byName map[string]*Lease
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}
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// newLeaseIndex returns a new index for [Lease]s.
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func newLeaseIndex() *leaseIndex {
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return &leaseIndex{
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byAddr: map[netip.Addr]*Lease{},
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byName: map[string]*Lease{},
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}
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}
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// leaseByAddr returns a lease by its IP address.
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func (idx *leaseIndex) leaseByAddr(addr netip.Addr) (l *Lease, ok bool) {
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l, ok = idx.byAddr[addr]
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return l, ok
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}
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// leaseByName returns a lease by its hostname.
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func (idx *leaseIndex) leaseByName(name string) (l *Lease, ok bool) {
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// TODO(e.burkov): Probably, use a case-insensitive comparison and store in
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// slice. This would require a benchmark.
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l, ok = idx.byName[strings.ToLower(name)]
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return l, ok
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}
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// clear removes all leases from idx.
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func (idx *leaseIndex) clear() {
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clear(idx.byAddr)
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clear(idx.byName)
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}
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// add adds l into idx and into iface. l must be valid, iface should be
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// responsible for l's IP. It returns an error if l duplicates at least a
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// single value of another lease.
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func (idx *leaseIndex) add(l *Lease, iface *netInterface) (err error) {
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loweredName := strings.ToLower(l.Hostname)
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if _, ok := idx.byAddr[l.IP]; ok {
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return fmt.Errorf("lease for ip %s already exists", l.IP)
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} else if _, ok = idx.byName[loweredName]; ok {
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return fmt.Errorf("lease for hostname %s already exists", l.Hostname)
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}
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err = iface.insertLease(l)
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if err != nil {
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return err
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}
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idx.byAddr[l.IP] = l
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idx.byName[loweredName] = l
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return nil
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}
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// remove removes l from idx and from iface. l must be valid, iface should
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// contain the same lease or the lease itself. It returns an error if the lease
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// not found.
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func (idx *leaseIndex) remove(l *Lease, iface *netInterface) (err error) {
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loweredName := strings.ToLower(l.Hostname)
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if _, ok := idx.byAddr[l.IP]; !ok {
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return fmt.Errorf("no lease for ip %s", l.IP)
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} else if _, ok = idx.byName[loweredName]; !ok {
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return fmt.Errorf("no lease for hostname %s", l.Hostname)
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}
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err = iface.removeLease(l)
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if err != nil {
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return err
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}
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delete(idx.byAddr, l.IP)
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delete(idx.byName, loweredName)
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return nil
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}
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// update updates l in idx and in iface. l must be valid, iface should be
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// responsible for l's IP. It returns an error if l duplicates at least a
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// single value of another lease, except for the updated lease itself.
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func (idx *leaseIndex) update(l *Lease, iface *netInterface) (err error) {
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loweredName := strings.ToLower(l.Hostname)
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existing, ok := idx.byAddr[l.IP]
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if ok && !slices.Equal(l.HWAddr, existing.HWAddr) {
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return fmt.Errorf("lease for ip %s already exists", l.IP)
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}
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existing, ok = idx.byName[loweredName]
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if ok && !slices.Equal(l.HWAddr, existing.HWAddr) {
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return fmt.Errorf("lease for hostname %s already exists", l.Hostname)
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}
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prev, err := iface.updateLease(l)
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if err != nil {
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return err
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}
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delete(idx.byAddr, prev.IP)
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delete(idx.byName, strings.ToLower(prev.Hostname))
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idx.byAddr[l.IP] = l
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idx.byName[loweredName] = l
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return nil
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}
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