Files
amsterdam/database/ipban.go
T

82 lines
2.2 KiB
Go

/*
* Amsterdam Web Communities System
* Copyright (c) 2025 Erbosoft Metaverse Design Solutions, All Rights Reserved
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
*/
// The database package contains database management and storage logic.
package database
import (
"fmt"
"math/big"
"net"
"sync"
"time"
)
// low64mask is bigint 0xFFFFFFFFFFFFFFFF, used in splitting large addresses.
var low64mask *big.Int
// knownBans is a cache of known banned addresses.
var knownBans map[string]string
// knownGood is a cache of known good IP addresses.
var knownGood map[string]bool
// banMutex synchronizes access to our cache.
var banMutex sync.Mutex
// init initializes the internals in this file.
func init() {
a := big.NewInt(1)
b := big.NewInt(0).Lsh(a, 64)
low64mask = big.NewInt(0).Sub(b, big.NewInt(1))
knownBans = make(map[string]string)
knownGood = make(map[string]bool)
}
/* AmTestIPBan tests an IP address to see if it's on the banned list.
* Parameters:
* ip_address - The IP address to be tested.
* Returns:
* Ban message if the address is banned, or empty string if it isn't.
* Standard Go error status.
*/
func AmTestIPBan(ip_address string) (string, error) {
banMutex.Lock()
defer banMutex.Unlock()
rc := knownBans[ip_address]
if rc != "" {
return rc, nil
}
if knownGood[ip_address] {
return "", nil
}
addr := net.ParseIP(ip_address)
if addr == nil {
return "", fmt.Errorf("invalid address %s", ip_address)
}
iv := big.NewInt(0)
iv.SetBytes(addr)
iv_lo := big.NewInt(0).And(iv, low64mask).Uint64()
iv_hi := big.NewInt(0).Rsh(iv, 64).Uint64()
rows, err := amdb.Query(`
SELECT message FROM ipban WHERE (address_lo & mask_lo) = (? & mask_lo)
AND (address_hi & mask_hi) = (? & mask_hi) AND (expire IS NULL OR expire >= ?)
AND enable <> 0 ORDER BY mask_hi DESC, mask_lo DESC`, iv_lo, iv_hi, time.Now().UTC())
if err != nil {
return "", err
}
defer rows.Close()
if rows.Next() {
rows.Scan(&rc)
knownBans[ip_address] = rc
return rc, nil
}
knownGood[ip_address] = true
return "", nil
}