[C sous UNIX] Sockets TCP/IP sous UNIX

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

#define MAX_SIZE 256
#define PORT 44412

int main(int argc, char *argv[])
{
struct hostent *hp = NULL;
struct sockaddr_in serv_ad, client_ad;
int sin_size,retour;
unsigned long addr;
int sockd, sockcli;
int valide;

if (argc != 2) 
{
	printf("Probleme d'arguments\n");
	exit (1);
}
hp = argv[1] ;
//open the socket
if ((sockd=socket(AF_INET, SOCK_DGRAM, 0))==-1)
{
	printf(" error open socket\n");
	return -1;
}

	
if (setsockopt(sockd, SOL_SOCKET, SO_REUSEADDR, &valide, sizeof(int))==-1) 	
{
	printf(" error set socket  options\n");
	return -1;
}

//configuration de serv_ad
serv_ad.sin_family=AF_INET; 
serv_ad.sin_port=htons(PORT); 
serv_ad.sin_addr.s_addr=hp->h_addr; 
serv_ad.sin_zero[8]=0; 
sin_size= hp->h_length;
if(bind(sockd, (struct sockaddr*)&serv_ad,sin_size)==-1)
{
	printf(" error bind\n");
	return -1;
}

if (connect(sockd,(struct sockaddr*)&serv_ad,sin_size)==1)
{
	printf(" error connect\n");
	return -1;
}

if (send(sockd,(char*)&serv_ad,sizeof(serv_ad),0)==-1)
{
	printf(" error send\n");
	return -1;
}

while(1) 
{
// lancement de l'attente de connexion client
	if (listen(sockd,5)==-1)
	{
		printf(" error listen\n");
		return -1;
	}

	if (accept(sockd,(struct sockaddr*)&serv_ad,&sin_size)==-1)
	{
		printf(" error accept\n");
		return -1;
	
	}
// dialogue avec le client
	retour = recv(socket,(char*)&serv_ad,sizeof(serv_ad),0 );
	if (retour == -1) 
	{
		printf(" error recv\n");
		return -1;
	}
	retour = send(socket,(char*)&serv_ad,sizeof(serv_ad),0 );
	if (retour == -1) 
	{
		printf(" error send\n");
		return -1;
	}
	
// fermeture socket client
	shutdown(sockcli,1);
	exit(0);
}

close(sockcli);

return 0;
}

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#define TAILLEMAX 256
#define PORT 44412

/* programme client */
main(int argc, char *argv[])
{
	int sd,lon,valide,retour;
	struct sockaddr_in adsock;
	struct hostent *hptr ; /* infos recuperes sur le host */
	char buf[TAILLEMAX] ; /*buffer de lecture des infos */
	char *host ; /*pointeur sur le nom du host distant */
	char *mesg ;


	if (argc != 2) 
	{
		printf("Probleme d'arguments\n");
		exit (1);
	}
	host = argv[1] ;


    lon=sizeof (hp->h_addr);
	adsock.sin_family=AF_INET; 
	adsock.sin_port=htons(PORT); 	
	memset (&adsock.sin_zero[8], 0, 1);
	memcpy (&adsock.sin_addr.s_addr, &hp->h_addr, lon);
	

   if ((sd=socket(AF_INET, SOCK_DGRAM, 0))==-1)
    {
        printf(" error open socket\n");
        return -1;
    }
    if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR, &valide, sizeof(int))==-1)
    {
        printf(" error set socket options\n");
        return -1;
    }

    if (connect(sd,(struct sockaddr*)&adsock,lon)==1)
    {
        printf(" error connect\n");
        return -1;
    }


    retour = send(sd,(char*)&adsock,sizeof(adsock),0 );
    if (retour == -1)
    {
        printf(" error send\n");
        return -1;
    }
    
    retour = recv(sd,(char*)&adsock,sizeof(adsock),0 );
    if (retour == -1)
    {
        printf(" error recv\n");
        return -1;
    }

	shutdown(sd);
	close(sd) ;
	exit(0) ;
}