[klippy]

This is not really related to module coding, but is more related to general C++, hope that doesn't mean I can't post this here.
So, I am a beginner C++ programmer(not that I am new to programming), and I just made one little program using WinSock2.h, right here:

PHP Code:

#include <iostream>
#include <WinSock2.h>

#pragma comment(lib, "ws2_32.lib")

typedef unsigned char BYTE;

#define MAXLEN    512

bool MasterServerResponse(char*);


int main(int argc, char* argv[])
{
    int sockMaster;
    WSADATA sockData;
    sockaddr_in addrOther;
    int sLen = sizeof(addrOther);

    if(WSAStartup(MAKEWORD(2,2), &sockData) != 0)
    {
        std::cout << "WSAStartup failed." << std::endl;
        return 1;
    }

    if((sockMaster = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == INVALID_SOCKET)
    {
        std::cout << "socket() failed." << std::endl;
        return 1;
    }

    memset(&addrOther, 0, sizeof(addrOther));
    addrOther.sin_family = AF_INET;
    addrOther.sin_port = htons(27010);
    addrOther.sin_addr.s_addr = inet_addr("hl1master.steampowered.com");


    char szBuffer[MAXLEN];
    BYTE byteIp[4] = {0, 0, 0, 0};
    unsigned short iPort = 0u;

    std::cout << "========== Queried servers ==========" << std::endl;
    goto startQuery;
    while(1)
    {
        if(byteIp[0] == 0 && byteIp[1] == 0 && byteIp[2] == 0 && byteIp[3] == 0 && iPort == 0)
            break;

        startQuery:
        
        // Query Master Server
        sprintf(szBuffer, "\x31\xFF%d.%d.%d.%d:%d\x00\x00", byteIp[0], byteIp[1], byteIp[2], byteIp[3], iPort);
        if(sendto(sockMaster, szBuffer, strlen(szBuffer) + 2/*for 2 null chars*/, 0, (sockaddr*)&addrOther, sizeof(addrOther)) == SOCKET_ERROR)
        {
            std::cout << "sendto() failed with error code: " << WSAGetLastError() << "." << std::endl;
            return 1;
        }

        memset(szBuffer, '\0', MAXLEN);

        if(recvfrom(sockMaster, szBuffer, MAXLEN, 0, (struct sockaddr*)&addrOther, &sLen) == SOCKET_ERROR)
        {
            std::cout << "recvfrom() failed." << std::endl;
            return 1;
        }

        // Parse the response
        if(MasterServerResponse(szBuffer))
        {
            byteIp[0] = szBuffer[6];
            byteIp[1] = szBuffer[7];
            byteIp[2] = szBuffer[8];
            byteIp[3] = szBuffer[9];
            iPort = (szBuffer[10] << 8) | szBuffer[11];
        }

        std::cout << static_cast<int>(byteIp[0]) << "." << static_cast<int>(byteIp[1]) << "."
            << static_cast<int>(byteIp[2]) << "." << static_cast<int>(byteIp[3]) << ":" << iPort << std::endl;
    }

    closesocket(sockMaster);
    WSACleanup();

    return 0;
}

bool MasterServerResponse(char* szResponse)
{
    return (szResponse[0] == 0xFF
        && szResponse[1] == 0xFF
        && szResponse[2] == 0xFF
        && szResponse[3] == 0xFF
        && szResponse[4] == 0x66
        && szResponse[5] == 0x0A);
} 


If it has any mistakes or whatever, just ignore it for now if it is not related to the problem. So, everything works good until it comes to sendto() function, which always reports an error. I searched for a while now over Google, but can't find the solution(there are solutions out there, but none of them helped me actually).
If you have any idea why is this error happening, please tell me. If you need anymore information than I gave here, just tell me and I will try to give you as much information as I can.

[claudiuhks]

PHP Code:

    ULONG addrHnd = inet_addr("hl1master.steampowered.com");

    if (addrHnd == INADDR_NONE)
        MessageBox(NULL, "Inet_Addr failed!", "Inet_Addr failed!", MB_OK | MB_ICONERROR); 


What do you think?

PHP Code:

PHOSTENT hostHnd = gethostbyname("hl1master.steampowered.com");
// hostHnd->h_addr, hostHnd->h_length 


[klippy]

Originally Posted by claudiuhks PHP Code:     ULONG addrHnd = inet_addr("hl1master.steampowered.com");     if (addrHnd == INADDR_NONE)         MessageBox(NULL, "Inet_Addr failed!", "Inet_Addr failed!", MB_OK | MB_ICONERROR);  What do you think? PHP Code: PHOSTENT hostHnd = gethostbyname("hl1master.steampowered.com"); // hostHnd->h_addr, hostHnd->h_length

Thank you for your reply!
Here is what I've done to check if it really works:

PHP Code:

if((addrOther.sin_addr.s_addr = inet_addr("hl1master.steampowered.com")) == INADDR_NONE)
        MessageBox(NULL, L"inet_addr() failed!", L"inet_addr() failed!", MB_OK | MB_ICONERROR); 


And it MessageBox'd me every time. I also pinged the masterserver from the command prompt, found out that VALVe's server is actually offline. So I found few working ones, and it works then, but I guess these ones weren't masterservers actually, but something other, because they gave me a random response buffer.

Originally Posted by claudiuhks PHP Code: PHOSTENT hostHnd = gethostbyname("hl1master.steampowered.com"); // hostHnd->h_addr, hostHnd->h_length

What did you want me to do with this one? Output hostHnd->h_addr and hosHnd->h_length? If so, here's the output(keep in mind that this is VALVe's non-working masterserver):


I output it with this code:

PHP Code:

PHOSTENT hostHnd = gethostbyname("hl1master.steampowered.com");
std::cout << "Len: " << hostHnd->h_length << " Address: " << hostHnd->h_addr << std::endl << std::endl; 


And what is gethostbyname() actually doing? Getting real IP address from a symbolic one(name)?

[klippy]

Nevermind, I got it to work. So if anyone is interested, here's the code:

PHP Code:

#include <iostream>
#include <vector>
#include <sstream>
#include <string>
#include <WinSock2.h>

#pragma comment(lib, "ws2_32.lib")

typedef unsigned char BYTE;

#define BUFLEN    5120


unsigned short BytesToShort(BYTE byte1, BYTE byte2)
{
    static union
    {
        BYTE bytes[2];
        unsigned short ushort;
    };

    bytes[1] = byte1;
    bytes[0] = byte2;

    return ushort;
}

/* Stream reading functions */
BYTE ReadByte(std::istringstream& stream)
{
    char szBuffer[1];
    stream.read(szBuffer, 1);
    return szBuffer[0];
}

unsigned short ReadShort(std::istringstream& stream)
{
    char szBuffer[2];
    stream.read(szBuffer, 2);
    return BytesToShort(szBuffer[0], szBuffer[1]);
}


int main(int argc, char* argv[])
{
    int sockMaster;
    WSADATA sockData;
    sockaddr_in addrOther;
    int sLen = sizeof(addrOther);

    if(WSAStartup(MAKEWORD(2,2), &sockData) != 0)
    {
        std::cout << "WSAStartup() failed." << std::endl;
        WSACleanup();

        return 1;
    }

    if((sockMaster = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == INVALID_SOCKET)
    {
        std::cout << "socket() failed." << std::endl;
        WSACleanup();

        return 1;
    }
    DWORD timeoutVal = 1000; // 1000 miliseconds / one second
    setsockopt(sockMaster, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeoutVal, sizeof(timeoutVal));

    char szBuffer[BUFLEN];
    std::string sInput, sIp, sPort;

    while(1)
    {
        std::cout << "Input IP:PORT of the MasterServer, or 0 to exit the program: ";
        std::getline(std::cin, sInput);
        if(sInput.c_str()[0] == '0')
            break;

        std::size_t portPos;
        if((portPos = sInput.find(':')) == std::string::npos)
        {
            std::cout << "You did not input the port number." << std::endl << std::endl;
            continue;
        }
        sIp = sInput.substr(0, portPos);
        sPort = sInput.substr(portPos + 1, std::string::npos);

        memset(&addrOther, 0, sizeof(addrOther));
        addrOther.sin_family = AF_INET;
        addrOther.sin_port = htons((unsigned short)atoi(sPort.c_str()));
        if((addrOther.sin_addr.s_addr = inet_addr(sIp.c_str())) == INADDR_NONE)
        {
            std::cout << "The entered IP address is invalid." << std::endl << std::endl;
            continue;
        }
        
        sprintf(szBuffer, "\x31\xFF\x30.0.0.0:0\x00\x00");
        if(sendto(sockMaster, szBuffer, 13, 0, (sockaddr*)&addrOther, sizeof(addrOther)) == SOCKET_ERROR)
        {
            std::cout << "sendto() failed with error code #" << WSAGetLastError() << "." << std::endl << std::endl;
            continue;
        }

        memset(szBuffer, '\0', BUFLEN);
        if(recvfrom(sockMaster, szBuffer, BUFLEN, 0, (struct sockaddr*)&addrOther, &sLen) == SOCKET_ERROR)
        {
            if(WSAGetLastError() == 10060)
                std::cout << "Error #10060: Request has timed out." << std::endl << std::endl;
            else
                std::cout << "recvfrom() failed with error code #" << WSAGetLastError() << "." << std::endl << std::endl;

            continue;
        }

        // Parse the response
        char szServer[22];
        BYTE byteIp[4] = {0, 0, 0, 0};
        unsigned short iPort = 0u;

        std::vector<std::string> serversArray;
        std::istringstream strBuffer(szBuffer);
        strBuffer.seekg(6); // Skip the first 6 bytes (xFF xFF xFF xFF x66 x0A)

        do
        {
            byteIp[0] = ReadByte(strBuffer);
            byteIp[1] = ReadByte(strBuffer);
            byteIp[2] = ReadByte(strBuffer);
            byteIp[3] = ReadByte(strBuffer);
            iPort = ReadShort(strBuffer);
            
            sprintf(szServer, "%d.%d.%d.%d:%u", (int)byteIp[0], (int)byteIp[1], (int)byteIp[2], (int)byteIp[3], iPort);
            serversArray.push_back(std::string(szServer));
        }
        while((int)strBuffer.tellg() != -1);
        serversArray.pop_back(); // Remove the last one

        std::cout << "========== Queried servers ==========" << std::endl;
        std::vector<std::string>::iterator iter;
        for(std::vector<std::string>::iterator iter = serversArray.begin(); iter != serversArray.end(); ++iter)
            std::cout << iter->c_str() << std::endl;

        std::cout << "Queried " << serversArray.size() << " servers in total." << std::endl << std::endl;
    }


    closesocket(sockMaster);
    WSACleanup();

    return 0;
} 


Its purpose is to query the master server. I know it may be badly written or ugly, but I don't really care, it's mostly for testing purposes.

[claudiuhks]

Thank you for sharing.
gethostbyname retrieves information from a name record.
Especially the IP address(es).

What is the Master Server IP address and its port?