xref: /freebsd/contrib/tcp_wrappers/ncr.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 }
82