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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 (
"database/sql"
"errors"
"fmt"
"net"
_ "github.com/mattn/go-sqlite3"
)
func loadDB(path string) (*sql.DB, error) {
db, err := sql.Open("sqlite3", fmt.Sprintf("file:%s", path))
if err != nil {
return nil, fmt.Errorf("failed to open database (%T): %w", err, err)
}
if _, err := db.Exec("create table if not exists leases4 (mac string not null, ip string not null, expiry int, hostname string not null, primary key (mac, ip))"); err != nil {
return nil, fmt.Errorf("table creation failed: %w", err)
}
return db, nil
}
// 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(db *sql.DB) (map[string]*Record, error) {
rows, err := db.Query("select mac, ip, expiry, hostname from leases4")
if err != nil {
return nil, fmt.Errorf("failed to query leases database: %w", err)
}
defer rows.Close()
var (
mac, ip, hostname string
expiry int
records = make(map[string]*Record)
)
for rows.Next() {
if err := rows.Scan(&mac, &ip, &expiry, &hostname); err != nil {
return nil, fmt.Errorf("failed to scan row: %w", err)
}
hwaddr, err := net.ParseMAC(mac)
if err != nil {
return nil, fmt.Errorf("malformed hardware address: %s", mac)
}
ipaddr := net.ParseIP(ip)
if ipaddr.To4() == nil {
return nil, fmt.Errorf("expected an IPv4 address, got: %v", ipaddr)
}
records[hwaddr.String()] = &Record{IP: ipaddr, expires: expiry, hostname: hostname}
}
if err := rows.Err(); err != nil {
return nil, fmt.Errorf("failed lease database row scanning: %w", err)
}
return records, nil
}
// saveIPAddress writes out a lease to storage
func (p *PluginState) saveIPAddress(mac net.HardwareAddr, record *Record) error {
stmt, err := p.leasedb.Prepare(`insert or replace into leases4(mac, ip, expiry, hostname) values (?, ?, ?, ?)`)
if err != nil {
return fmt.Errorf("statement preparation failed: %w", err)
}
defer stmt.Close()
if _, err := stmt.Exec(
mac.String(),
record.IP.String(),
record.expires,
record.hostname,
); err != nil {
return fmt.Errorf("record insert/update failed: %w", err)
}
return nil
}
// registerBackingDB installs a database connection string as the backing store for leases
func (p *PluginState) registerBackingDB(filename string) error {
if p.leasedb != nil {
return errors.New("cannot swap out a lease database while running")
}
// We never close this, but that's ok because plugins are never stopped/unregistered
newLeaseDB, err := loadDB(filename)
if err != nil {
return fmt.Errorf("failed to open lease database %s: %w", filename, err)
}
p.leasedb = newLeaseDB
return nil
}
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