Comparison Examples

The changes in client creation from TS-RPC to TI-RPC are illustrated in Example 6-1 and Example 6-2. Each example:

• Creates a UDP descriptor

• Contacts the remote host's RPC binding process to get the service's address

• Binds the remote service's address to the descriptor

• Creates the client handle and set its timeout

Example 6-1 Client Creation in TS-RPC

    struct hostent *h;
    struct sockaddr_in sin;
    int sock = RPC_ANYSOCK;
    u_short port;
    struct timeval wait;

    if ((h = gethostbyname( "host" )) == (struct hostent *) NULL)
{
        syslog(LOG_ERR, "gethostbyname failed");
        exit(1);
    }
    sin.sin_addr.s_addr = *(u_int *) hp->h_addr;
    if ((port = pmap_getport(&sin, PROGRAM, VERSION, "udp")) == 0) {
        syslog (LOG_ERR, "pmap_getport failed");
        exit(1);
    } else
        sin.sin_port = htons(port);
    wait.tv_sec = 25;
    wait.tv_usec = 0;
    clntudp_create(&sin, PROGRAM, VERSION, wait, &sock);

The TI-RPC version of client creation, shown in the following example, assumes that the UDP transport has the netid udp. A netid is not necessarily a well-known name.

Example 6-2 Client Creation in TI-RPC

    struct netconfig *nconf;
    struct netconfig *getnetconfigent();
    struct t_bind *tbind;
    struct timeval wait;

    nconf = getnetconfigent("udp");
    if (nconf == (struct netconfig *) NULL) {
        syslog(LOG_ERR, "getnetconfigent for udp failed");
        exit(1);
    }
    fd = t_open(nconf->nc_device, O_RDWR, (struct t_info *)NULL);
    if (fd == -1) {
        syslog(LOG_ERR, "t_open failed");
        exit(1);
    }
    tbind = (struct t_bind *) t_alloc(fd, T_BIND, T_ADDR);
    if (tbind == (struct t_bind *) NULL) {
        syslog(LOG_ERR, "t_bind failed");
        exit(1);
    }
    if (rpcb_getaddr( PROGRAM, VERSION, nconf, &tbind->addr, "host")
                                == FALSE) {
        syslog(LOG_ERR, "rpcb_getaddr failed");
        exit(1);
    }
    cl = clnt_tli_create(fd, nconf, &tbind->addr, PROGRAM, VERSION,
                          0, 0);
    (void) t_free((char *) tbind, T_BIND);
    if (cl == (CLIENT *) NULL) {
        syslog(LOG_ERR, "clnt_tli_create failed");
        exit(1);
    }
    wait.tv_sec = 25;
    wait.tv_usec = 0;
    clnt_control(cl, CLSET_TIMEOUT, (char *) &wait);

Example 6-3 and Example 6-4 show the differences between broadcast in TS-RPC and TI-RPC. The older clnt_broadcast() is similar to the newer rpc_broadcast(). The primary difference is in the collectnames() function: it deletes duplicate addresses and displays the names of hosts that reply to the broadcast.

Example 6-3 Broadcast in TS-RPC

statstime sw;
extern int collectnames();

clnt_broadcast(RSTATPROG, RSTATVERS_TIME, RSTATPROC_STATS,         
        xdr_void, NULL, xdr_statstime, &sw, collectnames);
    ...
collectnames(resultsp, raddrp)
    char *resultsp;
    struct sockaddr_in *raddrp;
{
    u_int addr;
    struct entry *entryp, *lim;
    struct hostent *hp;
    extern int curentry;

    /* weed out duplicates */
    addr = raddrp->sin_addr.s_addr;
    lim = entry + curentry;
    for (entryp = entry; entryp < lim; entryp++)
        if (addr == entryp->addr)
            return (0);
    ...
    /* print the host's name (if possible) or address */
    hp = gethostbyaddr(&raddrp->sin_addr.s_addr, sizeof(u_int),
        AF_INET);
    if( hp == (struct hostent *) NULL)
        printf("0x%x", addr);
    else
        printf("%s", hp->h_name);
}

The following code example shows broadcast in TI-RPC.

Example 6-4 Broadcast in TI-RPC

statstime sw;
extern int collectnames();

rpc_broadcast(RSTATPROG, RSTATVERS_TIME, RSTATPROC_STATS,
     xdr_void, NULL, xdr_statstime, &sw, collectnames, (char *)
0);
    ...

collectnames(resultsp, taddr, nconf)
    char *resultsp;
    struct t_bind *taddr;
    struct netconfig *nconf;
{
    struct entry *entryp, *lim;
    struct nd_hostservlist *hs;
    extern int curentry;
    extern int netbufeq();

    /* weed out duplicates */
    lim = entry + curentry;
    for (entryp = entry; entryp < lim; entryp++)
        if (netbufeq( &taddr->addr, entryp->addr))
            return (0);
    ...
    /* print the host's name (if possible) or address */
    if (netdir_getbyaddr( nconf, &hs, &taddr->addr ) == ND_OK)
        printf("%s", hs->h_hostservs->h_host);
    else {
        char *uaddr = taddr2uaddr(nconf, &taddr->addr);
        if (uaddr) {
            printf("%s\n", uaddr);
            (void) free(uaddr);
        } else
            printf("unknown");
    }
}
netbufeq(a, b)
    struct netbuf *a, *b;
{
    return(a->len == b->len && !memcmp( a->buf, b->buf, a->len));
}