Get ip address by url

ip.c

#include <stdio.h>
#include <string.h>

#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <netinet/in.h>

/**
 * Find ipv4 addresses (tcp) associated with given hostname
 * Inspired by: https://www.inetdoc.net/dev/socket-c-4and6/socket-c-4and6.getaddrinfo.html
 * See also example in: https://man7.org/linux/man-pages/man3/getaddrinfo.3.html
 *
 * Reference:
 * - Beej's Guide to Network Programming: https://beej.us/guide/bgnet/
 */
int main(int argc, char* argv[]) {
  // port=NULL => the port number of the returned socket addresses will be left uninitialized
  // char* hostname = "www.google.com";
  char* hostname = "www.soundcloud.com";
  char* port = NULL;
  typedef struct addrinfo addrinfo;

  // hints used to filters out returned addresses (its unset fields must contain 0 or NULL)
  addrinfo hints;
  memset(&hints, 0, sizeof(hints));
  hints.ai_family = AF_UNSPEC; // ipv4
  hints.ai_socktype = SOCK_STREAM; // tcp

  // returns a linked list bcoz same network could be accessible from tcp/udp, ipv4/ipv6...
  addrinfo* results;
  int ret = getaddrinfo(hostname, port, &hints, &results);

  if (ret != 0) {
    printf("Error while getting the addresses: %s\n", gai_strerror(ret));
    return 1;
  }

  // loop through found addresses
  addrinfo* result;
  for (result = results; result != NULL; result = result->ai_next) {
    // get address
    struct sockaddr* address = result->ai_addr;
    struct sockaddr_in* address_in = (struct sockaddr_in *) address;
    struct in_addr ip_address = address_in->sin_addr;

    // used instead of inet_ntoa() as it's obsolete
    char address_str[INET_ADDRSTRLEN];
    inet_ntop(AF_INET, &ip_address, address_str, INET_ADDRSTRLEN);

    // get protocol (tcp/udp)
    struct protoent* protocol = getprotobynumber(result->ai_protocol);

    // get family (ipv4 or ipv6)
    char* family = (result->ai_family == AF_INET) ? "ipv4" : "ipv6";

    printf("Address: %s, family: %s, protocol: %s \n", address_str, family, protocol->p_name);
  }

  // free allocated linked list
  freeaddrinfo(results);

  return 0;
}