[ RESOLU ]

Merci pour vos réponses. Pour ceux que cela interreserait, je poste la solution au problème.

#include pthread.h
#include sys/socket.h
#include netpacket/packet.h
#include net/ethernet.h
#include arpa/inet.h
#include sys/ioctl.h
#include linux/if.h
#include string.h
#include stdio.h
#include errno.h
int sock;
struct msghdr packet = {0};
struct sockaddr_ll addr = {0};
struct iovec iov = {0};
struct ifreq ifr = { 0 };
char *name="lo";
char buffer[1500] = {0};
pthread_t tid;
pthread_mutex_t mutex;
pthread_cond_t cond;
int recivelen;
fd_set readset;
struct timeval tv;
static void *reciver(void *arg)
{
	int datapresent;
	//synchronisation
	pthread_mutex_lock(&mutex);
	pthread_cond_signal(&cond);
	pthread_mutex_unlock(&mutex);
	//construction du select
	tv.tv_sec = 1;
	tv.tv_usec = 0;
	FD_ZERO(&readset);
	FD_SET(sock,&readset);
	// données présentes ?
	datapresent=select(sock+1, &readset,NULL,NULL,&tv);
	if(datapresent<=0)
	{
		// non
		printf("timeout\n");
		return NULL;
	}
		//oui
	recivelen=recvmsg(sock,&packet,MSG_DONTWAIT);
	printf("recvmsg return : %d\n",recivelen);
	return NULL;
}
int main()
{
	int errorCondition = 0;
	// overture de la socket
	sock = socket ( PF_PACKET, SOCK_DGRAM, htons ( ETH_P_ALL ) );
	if ( !sock )
		return -1;
	// attachement sur le loopback
	errorCondition = setsockopt ( sock,SOL_SOCKET,SO_BINDTODEVICE,name,2);
	if ( errorCondition )
		return errorCondition;
	// recupère l'index de l'interface. Pas utile ici mais on ne sait jamais
	strcpy ( ifr.ifr_name, name);
	errorCondition = ioctl ( sock, SIOCGIFINDEX, &ifr );
	if ( errorCondition )
		return errorCondition;
	//construction du packet
	addr.sll_family = AF_PACKET;
	addr.sll_ifindex = ifr.ifr_ifindex;
	addr.sll_halen = ETH_ALEN;
	addr.sll_protocol = htons ( ETH_P_ALL );
	packet.msg_name=&addr;
	packet.msg_namelen = sizeof ( struct sockaddr_ll );
	packet.msg_iov = &iov;
	packet.msg_iovlen = 1;
	iov.iov_base=&buffer;
	iov.iov_len=1500;
	packet.msg_control = NULL;
	packet.msg_controllen = 0;
	packet.msg_flags = 0;
	// initialisation du mutex pour une sychronisation
	pthread_mutex_init(&mutex,NULL);
	pthread_cond_init(&cond,NULL);
	// démarrage du thread d'écoute
	pthread_mutex_lock(&mutex);
	pthread_create(&tid,NULL,&reciver,NULL);
	// attente du bon démarrage, sinon ça fausse le test
	pthread_cond_wait(&cond,&mutex);
	pthread_mutex_unlock(&mutex);
	// attente de la fin du thread 
	pthread_join(tid,NULL);
	// fermeture avec close.
	errorCondition = close(sock);
	if(errorCondition)
		printf("close fail. errno : %d\n",errno);
}