setsockopt() returns 10042 error code with winsock.h-CodePudding

I am trying to listen a socket using multicast but it seems that am not using the setsockopt function well. I have been searching the meaning of the error code 10042 and I have found https://learn.microsoft.com/windows/win32/winsock/windows-sockets-error-codes-2 but I don't understand the explanation.

Here it is my function where I create a socket to listen a port inside a multicast group:

/* Includes */
#include <windows.h>
#include <winsock.h>
#include <iostream>
#include <cstdlib>
#pragma comment (lib, "Ws2_32.lib")

/* Defines */
#define BUFLEN                  1024
#define MULTICAST_GROUP                 "225.30.8.1"
#define LOCAL_IP                        "192.168.6.200"
#define DEFAULT_FTI_PORT                8600

/* Structs */
typedef struct {
    uint32_t receive_data[BUFLEN];          // receive data
}comm_data_t;

typedef struct {
    SOCKET sockfd;                      // RX socket ID
    int long_dir;                       // size of address
    struct sockaddr_in socket_addr;     // client socket struct
    struct sockaddr_in socket_sender;   // sender socket struct
    comm_data_t data;                   // data struct
}socket_t;



socket_t socket_info;

/* Returns 1 if succesfull, 0 otherwise */
uint8_t createSocket(void)
{
    WSADATA wsaData;
    struct ip_mreq mreq;                // multicast
    int iResult;

    cout << "IP: " << LOCAL_IP << endl;
    cout << "MULTICAST GROUP: " << MULTICAST_GROUP << endl;
    cout << "PORT: " << DEFAULT_FTI_PORT << endl << endl;

    // Initialize Winsock
    iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != 0) {
        printf("[SOCKET] WSAStartup failed with error: %d\n", iResult);
        return 0;
    }

    memset(&socket_info.socket_addr, 0, sizeof(socket_info.socket_addr));
    socket_info.socket_addr.sin_family = AF_INET;
    socket_info.socket_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    socket_info.socket_addr.sin_port = htons(DEFAULT_FTI_PORT);
    socket_info.long_dir = sizeof(socket_info.socket_sender);

    // Create a new socket to make a client connection.
    if ((socket_info.sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
    {
        printf("[SOCKET] socket() failed! Error code: %ld\n", WSAGetLastError());
        WSACleanup();
        return 0;
    }
    else
        printf("[SOCKET] socket() is OK!\n");

    if (bind(socket_info.sockfd, (struct sockaddr*) &socket_info.socket_addr, sizeof(socket_info.socket_addr)) < 0)
    {
        printf("[SOCKET] bind() failed! Error code: %ld\n", WSAGetLastError());
        return 0;
    }
    else
        printf("[SOCKET] bind() is OK!\n");

    // Set multicast option
    mreq.imr_multiaddr.s_addr = inet_addr(MULTICAST_GROUP);
    mreq.imr_interface.s_addr = inet_addr(LOCAL_IP);
    if ( (setsockopt(socket_info.sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*) &mreq, sizeof(mreq))) < 0)
    {
        printf("[SOCKET] setsockopt() failed! Error code: %ld\n", WSAGetLastError());
        return 0;
    }
    else
        printf("[SOCKET] setsockopt() is OK!\n");

    return 1;
}

And then I have another function where I read the received data:

/* Returns number of bytes received */
uint8_t readFromSocket(void)
{
    int32_t BytesReceived = 0;
    
    /* RECEIVE DATA */
     BytesReceived = recvfrom(socket_info.sockfd, (char*) &socket_info.data.receive_data,
                              BUFLEN, 0,
                              (struct sockaddr*) &socket_info.socket_sender,
                              &socket_info.long_dir); 
    
    if (BytesReceived < 0)
    {
        printf("[SOCKET] recvfrom() error %ld.\n", WSAGetLastError());
        return 0;
    }
    else
        return BytesReceived ;
}

It seems that I am not able to join myself to the multicast group, but I don't know where I am failing.

I am using UDP protocol, so if I change the parameter of setsockopt IPPROTO_IP to IPPROTO_UDP, I get the error code 10022.

What do these errors mean and how can I do it correctly?

CodePudding user response：

You're using an old set of include files. Instead of this:

#include <windows.h>
#include <winsock.h>

Use this:

#include <winsock2.h>
#include <ws2tcpip.h>

And it should work as expected.

CodePudding user response：

I have found the solution by my own.

I have being using another native .lib from Windows.

Before, on my header file I had:

#pragma comment (lib, "Ws2_32.lib")

But now, I use another .lib. This is the library that I am using right now and works for me:

#pragma comment (lib, "wsock32.lib")

I suppose that is a matter of distribution of my OS.

Thank you very much anyway for your comments.