banip_fakes

#include <amxmodx>

#define PLUGIN "BanIP Fakes"
#define VERSION "0.2"
#define AUTHOR "Safety1st"

/*---------------EDIT ME------------------*/
#define MAX_SAME_IP        3    // how many players allowed with the same IP address
#define BAN_DURATION       5
new gszKickMsg[] =         "Exceeded limit connections from one IP"

#define MAX_PLAYERS        32
//#define WHITELIST_SIZE   4    // EXACTLY as rows quantity below; uncomment to enable whitelist

#if defined WHITELIST_SIZE
new const gszWhiteList[WHITELIST_SIZE][] = {
    "127.0.0.0/8",         // loopback interface (usually assigned IP is 127.0.0.1)
    "192.168.0.0/24",      // 192.168.0.0/24 subnet, IPs range 192.168.0.0 ... 192.168.0.255
    "10.3.3.2/24",         // 10.3.3.0/24 subnet, we could use any of its IPs here
}
#endif
/*----------------------------------------*/

#define DEBUG    // uncomment to enable some messages

new gszPlayerIP[MAX_PLAYERS + 1][16]
new Trie:gtPlayerIPs

#if defined WHITELIST_SIZE
enum _:WhitelistData {
    NET_IP,
    NET_MASK
}
new Array:gaWhitelist
#endif

#define FIRST_PLAYER   1
#define SINGLE_PLAYER  1

public plugin_init() {
    register_plugin( PLUGIN, VERSION, AUTHOR )
    register_cvar( "banipfakes_version", VERSION, FCVAR_SERVER|FCVAR_SPONLY|FCVAR_UNLOGGED )

    gtPlayerIPs = TrieCreate()

#if defined WHITELIST_SIZE
    new iData[WhitelistData]
    gaWhitelist = ArrayCreate(WhitelistData)

    for( new i; i < WHITELIST_SIZE; i++ ) {
        net_to_long( gszWhiteList[i], iData[NET_IP], iData[NET_MASK] )
        ArrayPushArray( gaWhitelist, iData )
    }
#endif
}

public client_putinserver(id) {
    new szPlayerIP[16]
    get_user_ip( id, szPlayerIP, charsmax(szPlayerIP), 1 /* without port */ )

#if defined WHITELIST_SIZE
    new iData[WhitelistData]
    for( new i; i < WHITELIST_SIZE; i++ ) {
        ArrayGetArray( gaWhitelist, i, iData )
        if( iData[NET_IP] == ip_to_long(szPlayerIP) & iData[NET_MASK] ) {
            #if defined DEBUG
            server_print( "White IP detected: id %d, IP %s", id, szPlayerIP )
            #endif
            return
        }
    }
#endif

    new iQuantity = FIRST_PLAYER
    if( TrieGetCell( gtPlayerIPs, szPlayerIP, iQuantity ) ) {
        if( ++iQuantity > MAX_SAME_IP ) {
            server_cmd( "kick #%d  %s; wait; addip %d %s", get_user_userid(id), gszKickMsg, BAN_DURATION, szPlayerIP )
            static szBanMsg[] = "IP %s has been banned for %d minutes"
            log_amx( szBanMsg, szPlayerIP, BAN_DURATION )
        }
    }

    TrieSetCell( gtPlayerIPs, szPlayerIP, iQuantity )
    copy( gszPlayerIP[id], charsmax( gszPlayerIP[] ), szPlayerIP )
}

public client_disconnect(id) {
    if( !gszPlayerIP[id][0] )
        // whitelisted player or not fully initialized one (it could happen nearly a map change)
        return

    new iQuantity
    TrieGetCell( gtPlayerIPs, gszPlayerIP[id], iQuantity )
    if( iQuantity == SINGLE_PLAYER )
        TrieDeleteKey( gtPlayerIPs, gszPlayerIP[id] )
    else
        TrieSetCell( gtPlayerIPs, gszPlayerIP[id], --iQuantity )

    gszPlayerIP[id][0] = EOS
}

/*-- Modified and simplified 'IP converter stocks' by Zetex --*/

// Gets net and mask as LONG from subnet.
stock net_to_long( net_string[], &net, &mask ) {
    new i, ip[16]

    i = copyc( ip, charsmax(ip), net_string, '/' )
    mask = i ? cidr_to_long( net_string[i + 1] ) : 0xFFFFFFFF /* mask /32, IP itself */

    net = ip_to_long(ip) & mask
}

// Converts mask to LONG. Returns unsigned long.
stock cidr_to_long( mask_string[] ) {
    new mask = str_to_num(mask_string)
    new result = (1 << 31) >> (mask - 1)

    return result
}

// Converts IP to LONG. Returns unsigned long.
stock ip_to_long( ip_string[] ) {
    new right[16], part[4], octet, ip = 0
    strtok( ip_string, part, 3, right, 15, '.' )

    for( new i = 0; i < 4; i++ ) {
        octet = str_to_num(part)

        ip += octet

        if( i == 3 )
            break

        strtok( right, part, 3, right, 15, '.' )
        ip = ip << 8
    }

    return ip
}
/* AMXX-Studio Notes - DO NOT MODIFY BELOW HERE
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*/