SSDP/UPnP Discover Device IP from Windows

ssdp-win.cpp

// Windows CPP SSDP/UPNP search 230921

#pragma comment(lib, "Ws2_32.lib") // for socket
#include <windows.h>
#include <stdio.h>
#include <conio.h>
#include <sys/types.h>
#include <string.h>

constexpr auto SERVERPORT = 1900;
constexpr auto SSDP_GROUP = "239.255.255.250";
const char buff[] =
    "M-SEARCH * HTTP/1.1\r\n"
    "HOST: 239.255.255.250:1900\r\n"
    "MAN: \"ssdp:discover\"\r\n"
    "MX: 3\r\n"
    "ST: ssdp:all\r\n"
    "\r\n";

int main()
{
    char rcvdbuff[1000];
    int Ret = 2;
    int len;

    WSADATA wsaData;
    struct sockaddr_in their_addr;
    SOCKET sock;

    WSAStartup(MAKEWORD(2, 2), &wsaData);
    sock = socket(AF_INET, SOCK_DGRAM, 0);

    their_addr.sin_family = AF_INET;
    their_addr.sin_addr.s_addr = inet_addr(SSDP_GROUP);
    their_addr.sin_port = htons(SERVERPORT);
    len = sizeof(struct sockaddr_in);
    printf("Search:\n%s\n", buff);

    while (1)
    {
        Ret = sendto(sock, buff, strlen(buff), 0, (struct sockaddr*)&their_addr, len);
        if (Ret < 0)
        {
            printf("error in SENDTO() function");
            closesocket(sock);
            return 0;
        }

        //Receiving
      
        memset(rcvdbuff, 0, sizeof(rcvdbuff));
        Ret = recvfrom(sock, rcvdbuff, sizeof(rcvdbuff), 0, (struct sockaddr*)&their_addr, &len);
        if (Ret < 0){
            printf("Error in Receiving");
            return 0;
        }
        rcvdbuff[Ret - 1] = '\0';
        //printf("RECEIVED: %s\n\n", rcvdbuff);

        /* Parse valid responses to get IP */
        char host[1025];
        char* url_start, * host_start, * host_end;
        if (strncmp(rcvdbuff, "HTTP/1.1 200 OK", 12) == 0) {
            /* Skip ahead to url in SSDP response */
            if ((url_start = strstr(rcvdbuff, "LOCATION:" )) != NULL) {
                /* Get hostname/IP address in SSDP response */
                if ((host_start = strstr(url_start, "http://")) != NULL) {
                    host_start += 7; /* Move past "http://" */
                    if ((host_end = strstr(host_start, ":")) != NULL) {
                        strncpy_s(host, host_start, host_end - host_start);
                        host[host_end - host_start] = '\0';
                        printf("HOST IP: %s\n", host);
                    }
                }
            }
        }else{
            fprintf(stderr, "[Unexpected SSDP response]\n");
        }

        Sleep(5 * 1000);
    }
    closesocket(sock);
    WSACleanup();
}