Feature [TFS 1.0] Solution for Dynamic IP hosters

[rsdsebek]

Hi,
When I started hosting my server in my home not long ago, I found out, that I have Dynamic IP and I have to check if I can log in to my server couple times a day. It's well known issue - when your global IP changes, you have to restart your server in order to let other players log in, though. So I started to search for solution, and I wrote small piece of code, that checks IP of your domain (e.g. server.no-ip.org), and if IP is different than IP obtained at server startup, this code save and restarts your server. Works on pre-10.21 TFS 1.0 commits, on newest TFS 1.1 this code is unnecessary, because 10.21 client have ability to resolve host from domain name (in pre-10.21, server is sending resolved ip to client).

So let's go. All modifications are in otserv.cpp:
In otserv.cpp:
Find:

#include "networkmessage.h"

and under it add:

uint32_t previousIp = 0; //this variable is used to store your IP from server startup

Find:

void shutdown()
{
        g_scheduler.shutdown();
        g_dispatcher.shutdown();
}

and under it add:

void updateGlobalAddress()
{
    std::string ip = g_config.getString(ConfigManager::IP);
    uint32_t resolvedIp = inet_addr(ip.c_str());
    if (resolvedIp == INADDR_NONE) {
        struct hostent* he = gethostbyname(ip.c_str());
        if (!he) {
            std::ostringstream ss;
            ss << "ERROR: Cannot resolve " << ip << "!" << std::endl;
            startupErrorMessage(ss.str());
            return;
        }
        resolvedIp = *(uint32_t*)he->h_addr;
    }
    if (previousIp != resolvedIp) { //we have another IP, let's shutdown (restart) server
        struct in_addr ip_addr;
        ip_addr.s_addr = resolvedIp;
        std::cout << "> IP has changed to: " << inet_ntoa(ip_addr) << std::endl;
        std::cout << "> Restarting!" << std::endl;
        g_game.setGameState(GAME_STATE_SHUTDOWN);
    } else { //we have the same IP, executing updateGlobalAddress in 60 seconds
        g_scheduler.addEvent(createSchedulerTask(60 * 1000, boost::bind(updateGlobalAddress)));
    }
}

Find:

IpNetMask.first = resolvedIp;
IpNetMask.second = 0;
serverIPs.push_back(IpNetMask);

and add under it:

previousIp = resolvedIp; //let's store our IP from startup
updateGlobalAddress(); //call our new function

After compiling you have to change your ip in config.lua to your no-ip domain.
And that's it. From now on, if your server finds out, that your domain's IP has changed, it will save and restart itself.

Best
djseban

 

[Mark]

The code you are telling people to find has already been removed from TFS 1.0 (the IpNetMask stuff).

TFS 1.0 allows you to specify a hostname in config.lua for the "ip" config variable, so you can write "myserver.net" instead of the actual IP and if your IP changes too often you just set a low TTL on the DNS.

 

[rsdsebek]

Many people like me, are forced to use protocol 9.81 (since in my project dat editor is essential tool, by this time there isn't any for 10.10+). Unfortunately 9.81 doesn't support passing IP as string to client, so there isn't any possibility to skip IP changing "feature". Anyway, thanks for feedback. I will add note in thread.

Best
Sebastian

 

[upking]

Could you make this work in 8.6?