mirror of
https://github.com/coredhcp/coredhcp.git
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da62c7b1bd
Implement DHCP RELEASE message handling in the range plugin Signed-off-by: Nikita Vakula <programmistov.programmist@gmail.com>
108 lines
3.3 KiB
Go
108 lines
3.3 KiB
Go
// Copyright 2018-present the CoreDHCP Authors. All rights reserved
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// This source code is licensed under the MIT license found in the
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// LICENSE file in the root directory of this source tree.
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package rangeplugin
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import (
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"database/sql"
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"errors"
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"fmt"
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"net"
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_ "github.com/mattn/go-sqlite3"
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)
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func loadDB(path string) (*sql.DB, error) {
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db, err := sql.Open("sqlite3", fmt.Sprintf("file:%s", path))
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if err != nil {
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return nil, fmt.Errorf("failed to open database (%T): %w", err, err)
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}
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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 {
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return nil, fmt.Errorf("table creation failed: %w", err)
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}
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return db, nil
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}
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// loadRecords loads the DHCPv6/v4 Records global map with records stored on
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// the specified file. The records have to be one per line, a mac address and an
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// IP address.
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func loadRecords(db *sql.DB) (map[string]*Record, error) {
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rows, err := db.Query("select mac, ip, expiry, hostname from leases4")
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if err != nil {
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return nil, fmt.Errorf("failed to query leases database: %w", err)
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}
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defer rows.Close()
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var (
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mac, ip, hostname string
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expiry int
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records = make(map[string]*Record)
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)
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for rows.Next() {
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if err := rows.Scan(&mac, &ip, &expiry, &hostname); err != nil {
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return nil, fmt.Errorf("failed to scan row: %w", err)
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}
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hwaddr, err := net.ParseMAC(mac)
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if err != nil {
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return nil, fmt.Errorf("malformed hardware address: %s", mac)
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}
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ipaddr := net.ParseIP(ip)
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if ipaddr.To4() == nil {
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return nil, fmt.Errorf("expected an IPv4 address, got: %v", ipaddr)
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}
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records[hwaddr.String()] = &Record{IP: ipaddr, expires: expiry, hostname: hostname}
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}
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if err := rows.Err(); err != nil {
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return nil, fmt.Errorf("failed lease database row scanning: %w", err)
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}
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return records, nil
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}
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// saveIPAddress writes out a lease to storage
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func (p *PluginState) saveIPAddress(mac net.HardwareAddr, record *Record) error {
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stmt, err := p.leasedb.Prepare(`insert or replace into leases4(mac, ip, expiry, hostname) values (?, ?, ?, ?)`)
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if err != nil {
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return fmt.Errorf("statement preparation failed: %w", err)
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}
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defer stmt.Close()
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if _, err := stmt.Exec(
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mac.String(),
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record.IP.String(),
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record.expires,
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record.hostname,
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); err != nil {
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return fmt.Errorf("record insert/update failed: %w", err)
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}
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return nil
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}
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// freeIPAddress removes a lease from storage
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func (p *PluginState) freeIPAddress(mac net.HardwareAddr, record *Record) error {
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stmt, err := p.leasedb.Prepare(`delete from leases4 where mac = ? and ip = ?`)
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if err != nil {
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return fmt.Errorf("statement preparation failed: %w", err)
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}
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defer stmt.Close()
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if _, err := stmt.Exec(
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mac.String(),
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record.IP.String(),
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); err != nil {
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return fmt.Errorf("record delete failed: %w", err)
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}
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return nil
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}
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// registerBackingDB installs a database connection string as the backing store for leases
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func (p *PluginState) registerBackingDB(filename string) error {
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if p.leasedb != nil {
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return errors.New("cannot swap out a lease database while running")
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}
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// We never close this, but that's ok because plugins are never stopped/unregistered
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newLeaseDB, err := loadDB(filename)
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if err != nil {
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return fmt.Errorf("failed to open lease database %s: %w", filename, err)
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}
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p.leasedb = newLeaseDB
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return nil
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}
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