sysdis-project/sgca/lib/local/middleware.c

/**************************
*  Middleware Dependency  *
***************************
* Designed & Developed by *
*     Adrien Marquès      *
*     <xdrm-brackets>     *
***************************
*   doowap31@gmail.com    *
**************************/
#include "middleware.h"





int multicastTerminal(struct middleware_arg* arg){
    /* [0] Initialisation
    =========================================================*/
    /* 1. Initialisation des variables */
	struct sockaddr_in     comInfo;                                  // contiendra les infos de la socket COM
	struct sockaddr_in     clientInfo;                               // contiendra les infos client
	socklen_t              len;                                      // taille de la socket
	int                    read;                                     // compteurs
	char                   buffer[MAX_BUF_LEN+1];                    // buffer requête
	struct bind_header     request;                                  // requête parsée
    struct in_addr         ip;                                       // Pour afficher une ip en dot notation

    /* 2. On récupère l'IP locale */
    struct in_addr* SERV_IP = GET_LOCAL_IP();
	if( SERV_IP == NULL ){
        printf("{%s}              /!\\ Cannot fetch local ip address. Aborting!\n", arg->entity);
        return -2;
    }

    /* 3. On attends une connection UDP */
    len = sizeof(struct sockaddr_in);
    read = recvfrom(arg->listenSock, buffer, MAX_BUF_LEN, 0, (struct sockaddr*) &clientInfo, &len);

    /* 4. Si erreur reception ou taille incorrecte -> retour à l'écoute */
    if( read < BINDHDR_LEN ){
        if( DEBUGMOD&BUF ) printf("{%s}              read('%s') = %d bytes (expected: %d)\n", arg->entity, buffer, read, (int) (BINDHDR_LEN) );
        return -1;
    }

    /* 5. On récupère l'adresse IP du client */
    if( DEBUGMOD&SCK ) printf("{%s}              %s:%d connecté\n", arg->entity, inet_ntoa(clientInfo.sin_addr), ntohs(clientInfo.sin_port));



    /* [1] Gestion de la requête
    =========================================================*/
    /* 1. On parse la requête */
    memcpy(&request.flags, buffer,                                sizeof(char));
    memcpy(&request.addr,  buffer+sizeof(char),                   sizeof(in_addr_t));
    memcpy(&request.port,  buffer+sizeof(char)+sizeof(in_addr_t), sizeof(unsigned short));
    request.addr = ntohl(request.addr);
    ip.s_addr = request.addr;
    if( DEBUGMOD&COM ) printf("{%s}              received: bind_header{flag = %d; addr = %x/'%s'; port = %d}\n", arg->entity, (int) request.flags, ntohl(request.addr), inet_ntoa(ip), request. port);

    /* 2. Si mauvais flag (avion) */
    if( request.flags&BINDHEAD_TCP || !(request.flags&BINDHEAD_UDP) ){
        printf("{%s}              Invalid flag\n", arg->entity);
        return -1;
    }

    /* 3. Si mauvais flag (mauvais type de terminal) */
    if( request.flags&BINDHEAD_CTL ){

        // vterm avec flag cterm
        if( strcmp(arg->entity, "udp_vterm") == 0 ){
            printf("{%s}              Invalid flag\n", arg->entity);
            return -1;
        }

    // cterm avec flag vterm
    }else if( strcmp(arg->entity, "udp_cterm") == 0 ){
        printf("{%s}              Invalid flag\n", arg->entity);
        return -1;
    }




    /* (1) Création socket de communication (si demandé)
    ---------------------------------------------------------*/
    /* 1. On bind une socket sur un port random */
    if( DROP_UDP_SERVER(SERV_IP->s_addr, 0, arg->comSock, &comInfo, 0) < 0 ){

        if( DEBUGMOD&SCK ) printf("{%s}              Cannot create COMmunication socket\n", arg->entity);

        /* 2. On ferme la socket et enleve le FLAG pour dire qu'on a pas pu ouvrir le port */
        close(*arg->comSock);
        request.flags -= BINDHEAD_UDP;
    }

    /* 3. On définit un timeout (si aucune connection) */
    /* 3.1. Si viewTerm -> default timeout (4sec) */
    if( strcmp(arg->entity, "udp_vterm") == 0 ){
        if( setTimeout(*arg->comSock, SOCK_TIMEOUT, TIMEOUT_RECV|TIMEOUT_SEND) < 0 ){
            if( DEBUGMOD&SCK ) printf("{%s}              Cannot set RECV not SEND timeout\n", arg->entity);
        }else
            if( DEBUGMOD&SCK ) printf("{%s}              SEND/RECV timeout set to %d\n", arg->entity, SOCK_TIMEOUT);
    /* 3.2. Si ctrlTerm -> 10sec timeout */
    }else
        if( setTimeout(*arg->comSock, CTRL_TIMEOUT, TIMEOUT_RECV|TIMEOUT_SEND) < 0 ){
            if( DEBUGMOD&SCK ) printf("{%s}              Cannot set RECV not SEND timeout\n", arg->entity);
        }else
            if( DEBUGMOD&SCK ) printf("{%s}              SEND/RECV timeout set to %d\n", arg->entity, CTRL_TIMEOUT);





    /* (2) Récupération port random
    ---------------------------------------------------------*/
    /* 1. On récupère le port de la socket de communication */
    len = sizeof(struct sockaddr_in);
    if( getsockname(*arg->comSock, (struct sockaddr*) &comInfo, &len) < 0 ){

        if( DEBUGMOD&SCK ) printf("{%s}              Cannot find opened port from socket\n", arg->entity);

        /* 2. On ferme la socket et enleve le FLAG pour dire qu'on a pas pu ouvrir le port */
        close(*arg->comSock);
        request.flags -= BINDHEAD_UDP;

    /* 3. Si on a le port -> on le met dans la reponse */
    }else{
        request.addr = SERV_IP->s_addr;
        request.port = comInfo.sin_port;
        if( DEBUGMOD&SCK ) printf("{%s}{com}         socket opened on %s:%d\n", arg->entity, inet_ntoa(*SERV_IP), ntohs(request.port));
    }



    /* [2] Envoi de la réponse
    =========================================================*/
    /* 1. On sérialise la réponse */
    bzero(buffer, MAX_BUF_LEN*sizeof(char));
    memcpy(buffer,                                &request.flags, sizeof(char));
    memcpy(buffer+sizeof(char),                   &request.addr,  sizeof(in_addr_t));
    memcpy(buffer+sizeof(char)+sizeof(in_addr_t), &request.port,  sizeof(unsigned short));

    /* 2. On envoie la réponse*/
    len = sizeof(struct sockaddr_in);
    if( sendto(arg->listenSock, buffer, BINDHDR_LEN/sizeof(char) + 1, 0, (struct sockaddr*) &clientInfo, len) < 0 ){
        printf("{%s}              Cannot answer to client\n", arg->entity);
        return -2;
    }

    if( DEBUGMOD&COM ) printf("{%s}              sent: bind_header{flag = %d; addr = %x/'%s'; port = %d}\n", arg->entity, (int) request.flags, ntohl(request.addr), inet_ntoa(*SERV_IP), ntohs(request.port));


    return 0;

}