TP3_SOCKET/client_echo.c

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define BUF_SIZE 500

struct addrinfo *result;                 // tableau des adresses réseaux des serveurs

int cree_socket(char* ip, char* port, struct addrinfo hints){
  int s = getaddrinfo(ip, port, &hints, &result);
  if (s != 0) {
    fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
    s = 1;
  }
  return s;
}

int main(int argc, char *argv[]) {
  struct addrinfo hints;
  struct addrinfo *rp;
  int sfd, s, j;
  size_t len;
  ssize_t nread;
  char buf[BUF_SIZE];

  if (argc < 3) {                     // vérification du nombre d'arguments rentrés
    fprintf(stderr, "mettre: %s ip port message\n", argv[0]);
    exit(EXIT_FAILURE);
  }

  char* ip = argv[1];
  char* port = argv[2];
  char* message = argv[3];            // remplissage des varables a partir des arguments passés au programme

  /* Obtain address(es) matching host/port */
  memset(&hints, 0, sizeof(struct addrinfo));
  hints.ai_family = AF_UNSPEC;    /* Allow IPv4 or IPv6 */
  hints.ai_socktype = SOCK_DGRAM; /* Datagram socket */
  hints.ai_flags = 0;
  hints.ai_protocol = 0;          /* Any protocol */

  s = cree_socket(ip, port, hints);                 // création du socket
  if(s == 1) {
    exit(EXIT_FAILURE);
  }

  /* getaddrinfo () retourne une liste de structures d'adresses.
  Essayez chaque adresse jusqu'à ce que nous ayons réussi à bind(2).
  Si socket() (ou bind()) échoue, nous (fermons le socket et)
  essayons l'adresse suivante */

  for (rp = result; rp != NULL; rp = rp->ai_next) {
    sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
    if (sfd == -1){
      continue;
    }
    if (connect(sfd, rp->ai_addr, rp->ai_addrlen) != -1){
      break;                  /* Success */
    }
    close(sfd);
  }

  if (rp == NULL) {               /* No address succeeded */
    fprintf(stderr, "Could not connect\n");
    exit(EXIT_FAILURE);
  }

  freeaddrinfo(result);           /* No longer needed */

  /* Send remaining command-line arguments as separate
  datagrams, and read responses from server */

  for (j = 3; j < argc; j++) {
    len = strlen(argv[j]) + 1;
    /* +1 for terminating null byte */
    if (len + 1 > BUF_SIZE) {
      fprintf(stderr, "Ignoring long message in argument %d\n", j);
      continue;
    }
    if (write(sfd, argv[j], len) != len) {
      fprintf(stderr, "partial/failed write\n");
      exit(EXIT_FAILURE);
    }
    nread = read(sfd, buf, BUF_SIZE);
    if (nread == -1) {
      perror("read");
      exit(EXIT_FAILURE);
    }
    printf("Received %ld bytes: %s\n", (long) nread, buf);
  }
  exit(EXIT_SUCCESS);
}