contrib/tcp_wrappers/ncr.c

   1  /*
   2   * This part for NCR UNIX with is from Andrew Maffei (arm@aqua.whoi.edu). It
   3   * assumes TLI throughout. In order to look up endpoint address information
   4   * we must talk to the "timod" streams module. For some reason "timod" wants
   5   * to sit directly on top of the device driver. Therefore we pop off all
   6   * streams modules except the driver, install the "timod" module so that we
   7   * can figure out network addresses, and then restore the original state.
   8   */
   9
  10 #ifndef lint
  11 static char sccsid[] = "@(#) ncr.c 1.1 94/12/28 17:42:34";
  12 #endif
  13
  14 #include <sys/types.h>
  15 #include <stdio.h>
  16 #include <syslog.h>
  17 #include <sys/tiuser.h>
  18 #include <stropts.h>
  19 #include <sys/conf.h>
  20
  21 #include "tcpd.h"
  22
  23 #define MAX_MODULE_COUNT        10      /* XXX */
  24
  25 /* fromhost - tear down the streams stack then rebuild it */
  26
  27 void    fromhost(request)
  28 struct request_info *request;
  29 {
  30     int     i;
  31     int     num_mod;
  32     struct str_list str_list;
  33     struct str_mlist mod_buffer[MAX_MODULE_COUNT];
  34     int     fd = request->fd;
  35
  36     str_list.sl_nmods = MAX_MODULE_COUNT;
  37     str_list.sl_modlist = &mod_buffer[0];
  38
  39     /*
  40      * On systems with WIN streams support we have to be careful about what
  41      * is on the stream we are passed. This code POPs off all modules above
  42      * the pseudo driver, pushes timod, gets the host address information,
  43      * pops timod and then pushes all modules back on the stream.
  44      *
  45      * Some state may be lost in this process. /usr/etc/tlid seems to do special
  46      * things to the stream depending on the TCP port being serviced. (not a
  47      * very nice thing to do!). It is unclear what to do if this code breaks
  48      * - the stream may be left in an unknown condition.
  49      */
  50     if ((num_mod = ioctl(fd, I_LIST, NULL)) < 0)
  51         tcpd_warn("fromhost: LIST failed: %m");
  52     if (ioctl(fd, I_LIST, &str_list) < 0)
  53         tcpd_warn("fromhost: LIST failed: %m");
  54
  55     /*
  56      * POP stream modules except for the driver.
  57      */
  58     for (i = 0; i < num_mod - 1; i++)
  59         if (ioctl(fd, I_POP, 0) < 0)
  60             tcpd_warn("fromhost: POP %s: %m", mod_buffer[i].l_name);
  61
  62     /*
  63      * PUSH timod so that host address ioctls can be executed.
  64      */
  65     if (ioctl(fd, I_PUSH, "timod") < 0)
  66         tcpd_warn("fromhost: PUSH timod: %m");
  67     tli_host(request);
  68
  69     /*
  70      * POP timod, we're done with it now.
  71      */
  72     if (ioctl(fd, I_POP, 0) < 0)
  73         tcpd_warn("fromhost: POP timod: %m");
  74
  75     /*
  76      * Restore stream modules.
  77      */
  78     for (i = num_mod - 2; i >= 0; i--)
  79         if (ioctl(fd, I_PUSH, mod_buffer[i].l_name) < 0)
  80             tcpd_warn("fromhost: PUSH %s: %m", mod_buffer[i].l_name);
  81 }