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urtrator/requester/requester_object.go

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// URTator - Urban Terror server browser and game launcher, written in
// Go.
//
// Copyright (c) 2016, Stanslav N. a.k.a pztrn (or p0z1tr0n)
// All rights reserved.
//
// Licensed under Terms and Conditions of GNU General Public License
// version 3 or any higher.
// ToDo: put full text of license here.
package requester
import (
// stdlib
"bytes"
"fmt"
"net"
"strconv"
"strings"
"sync"
"time"
// local
"github.com/pztrn/urtrator/datamodels"
)
type Requester struct {
// Master server address
master_server string
// Master server port
master_server_port string
// Packet prefix.
pp string
// Showstopper for delimiting IP addresses.
// As we are receiving bytes, we will put bytes representation of "\"
// character.
ip_delimiter int
}
// Requester's initialization.
func (r *Requester) Initialize() {
fmt.Println("Initializing Requester...")
r.master_server = "master.urbanterror.info"
r.master_server_port = "27900"
r.pp = "\377\377\377\377"
r.ip_delimiter = 92
}
// Gets all available servers from master server.
func (r *Requester) getServers(callback chan [][]string) {
// IP addresses we will compose to return.
var received_ips [][]string
conn, err1 := net.Dial("udp", r.master_server + ":" + r.master_server_port)
if err1 != nil {
fmt.Println("Error dialing to master server!")
}
defer conn.Close()
// Set deadline, so we won't wait forever.
ddl := time.Now()
// This should be enough. Maybe, you should'n run URTrator on modem
// connections? :)
ddl = ddl.Add(time.Second * 2)
conn.SetDeadline(ddl)
fmt.Println("Master server connection deadline set: " + ddl.String())
// Request.
// 68 - protocol version for 4.3
// 70 - protocol version for 4.2.x
msg := []byte(r.pp + "getservers 68 full empty")
conn.Write(msg)
// UDP Buffer.
var received_buf []byte = make([]byte, 4096)
// Received buffer.
var raw_received []byte
// Received IP addresses.
//var received []string
fmt.Println("Receiving servers list...")
for {
_, err := conn.Read(received_buf)
if err != nil {
break
}
raw_received = append(raw_received, received_buf...)
fmt.Println("Received " + strconv.Itoa(len(raw_received)) + " bytes")
}
// Obtaining list of slices.
var raw_received_slices [][]byte = bytes.Split(raw_received, []byte("\\"))
// Every ip-port pair contains:
// 1. IP as first 4 bytes
// 2. Port as last 2 bytes.
// Every package is a 7-bytes sequence, which starts with "\"
// (code 92), which we used before to obtain list of slices.
for _, slice := range raw_received_slices {
// We need only 6-bytes slices. All other aren't represent
// server's address.
if len(slice) != 6 {
continue
}
// Generate IP.
ip := strconv.Itoa(int(slice[0])) + "." + strconv.Itoa(int(slice[1])) + "." + strconv.Itoa(int(slice[2])) + "." + strconv.Itoa(int(slice[3]))
// Generate port from last two bytes.
// This is a very shitty thing. Don't do this in real world.
// Maybe bitshifting will help here, but I can't get it to work :(
// Get first byte as integer and multiply it on 256 and summing with
// second byte.
p1 := int(slice[4]) * 256
port := strconv.Itoa(p1 + int(slice[5]))
// Create a slice with IP and port.
ip_and_port := []string{ip, port}
// Add it to received_ips.
received_ips = append(received_ips, ip_and_port)
}
fmt.Println("Parsed " + strconv.Itoa(len(received_ips)) + " addresses")
callback <- received_ips
}
// Updates information about all available servers from master server and
// parses it to usable format.
func (r *Requester) UpdateAllServers(done_chan chan map[string]*datamodels.Server, error_chan chan bool) {
fmt.Println("Starting all servers updating procedure...")
callback := make(chan [][]string)
go r.getServers(callback)
servers := make(map[string]*datamodels.Server)
select {
case data := <- callback:
// Yay, we got data! :)
fmt.Println("Received " + strconv.Itoa(len(data)) + " servers")
servers = r.updateServerGoroutineDispatcher(data)
break
case <- time.After(time.Second * 10):
// Timeouted? Okay, push error back.
error_chan <- true
}
done_chan <- servers
}
func (r *Requester) updateServerGoroutineDispatcher(data [][]string) map[string]*datamodels.Server {
var wait sync.WaitGroup
var lock = sync.RWMutex{}
done_updating := 0
servers := make(map[string]*datamodels.Server)
for _, s := range data {
s := datamodels.Server{
Ip: s[0],
Port: s[1],
}
go func(s *datamodels.Server, servers map[string]*datamodels.Server) {
wait.Add(1)
defer wait.Done()
r.UpdateServer(s)
done_updating = done_updating + 1
lock.Lock()
servers[s.Ip + ":" + s.Port] = s
lock.Unlock()
}(&s, servers)
}
wait.Wait()
return servers
}
// Updates information about specific server.
func (r *Requester) UpdateServer(server *datamodels.Server) {
srv := server.Ip + ":" + server.Port
fmt.Println("Updating server: " + srv)
// Dial to server.
conn, err1 := net.Dial("udp", srv)
if err1 != nil {
fmt.Println("Error dialing to server " + srv + "!")
}
defer conn.Close()
// Set deadline, so we won't wait forever.
ddl := time.Now()
// This should be enough. Maybe, you should'n run URTrator on modem
// connections? :)
ddl = ddl.Add(time.Second * 2)
conn.SetDeadline(ddl)
msg := []byte(r.pp + "getinfo")
conn.Write(msg)
// UDP Buffer.
var received_buf []byte = make([]byte, 4096)
// Received buffer.
var raw_received []byte
for {
_, err := conn.Read(received_buf)
if err != nil {
break
}
raw_received = append(raw_received, received_buf...)
}
// First line is "infoResponse" string, which we should skip by
// splitting response by "\n".
received_lines := strings.Split(string(raw_received), "\n")
// We have server's data!
if len(received_lines) > 1 {
srv_config := strings.Split(received_lines[1], "\\")
// Parse server configuration into passed server's datamodel.
for i := 0; i < len(srv_config); i = i + 1 {
if srv_config[i] == "modversion" {
server.Version = srv_config[i + 1]
}
if srv_config[i] == "gametype" {
server.Gamemode = srv_config[i + 1]
}
if srv_config[i] == "sv_maxclients" {
server.Maxplayers = srv_config[i + 1]
}
if srv_config[i] == "clients" {
server.Players = srv_config[i + 1]
}
if srv_config[i] == "mapname" {
server.Map = srv_config[i + 1]
}
if srv_config[i] == "hostname" {
server.Name = srv_config[i + 1]
}
}
}
// ToDo: Calculate ping. 0 for now.
server.Ping = "0"
}