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// Copyright 2018-present the CoreDHCP Authors. All rights reserved
// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.
package rangeplugin
import (
"bufio"
"errors"
"fmt"
"io"
"net"
"os"
"strings"
"time"
)
// loadRecords loads the DHCPv6/v4 Records global map with records stored on
// the specified file. The records have to be one per line, a mac address and an
// IP address.
func loadRecords(r io.Reader) (map[string]*Record, error) {
sc := bufio.NewScanner(r)
records := make(map[string]*Record)
for sc.Scan() {
line := sc.Text()
if len(line) == 0 {
continue
}
tokens := strings.Fields(line)
if len(tokens) != 3 {
return nil, fmt.Errorf("malformed line, want 3 fields, got %d: %s", len(tokens), line)
}
hwaddr, err := net.ParseMAC(tokens[0])
if err != nil {
return nil, fmt.Errorf("malformed hardware address: %s", tokens[0])
}
ipaddr := net.ParseIP(tokens[1])
if ipaddr.To4() == nil {
return nil, fmt.Errorf("expected an IPv4 address, got: %v", ipaddr)
}
expires, err := time.Parse(time.RFC3339, tokens[2])
if err != nil {
return nil, fmt.Errorf("expected time of exipry in RFC3339 format, got: %v", tokens[2])
}
records[hwaddr.String()] = &Record{IP: ipaddr, expires: expires}
}
return records, nil
}
func loadRecordsFromFile(filename string) (map[string]*Record, error) {
reader, err := os.OpenFile(filename, os.O_RDWR|os.O_CREATE, 0640)
defer func() {
if err := reader.Close(); err != nil {
log.Warningf("Failed to close file %s: %v", filename, err)
}
}()
if err != nil {
return nil, fmt.Errorf("cannot open lease file %s: %w", filename, err)
}
return loadRecords(reader)
}
// saveIPAddress writes out a lease to storage
func (p *PluginState) saveIPAddress(mac net.HardwareAddr, record *Record) error {
_, err := p.leasefile.WriteString(mac.String() + " " + record.IP.String() + " " + record.expires.Format(time.RFC3339) + "\n")
if err != nil {
return err
}
err = p.leasefile.Sync()
if err != nil {
return err
}
return nil
}
// registerBackingFile installs a file as the backing store for leases
func (p *PluginState) registerBackingFile(filename string) error {
if p.leasefile != nil {
// This is TODO; swapping the file out is easy
// but maintaining consistency with the in-memory state isn't
return errors.New("cannot swap out a lease storage file while running")
}
// We never close this, but that's ok because plugins are never stopped/unregistered
newLeasefile, err := os.OpenFile(filename, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
if err != nil {
return fmt.Errorf("failed to open lease file %s: %w", filename, err)
}
p.leasefile = newLeasefile
return nil
}
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