usr.sbin/pppd/plugins/status/status.c

   1 /*      $NetBSD: status.c,v 1.2 2006/12/25 18:39:48 wiz Exp $   */
   2
   3 /*
   4  * status.c - pppd plugin to implement an `lcpstatus' option.
   5  * This is intended as more of an example than perfected feature,
   6  * but this code has been in use on my local network for a year and
   7  * is quite useful as is (with a bit of external help, at any rate).
   8  *
   9  * Written January 2003 by John F. Woods, jfw@funhouse.com
  10  */
  11
  12 /*
  13  * Copyright (c) 2004 The NetBSD Foundation, Inc.
  14  * All rights reserved.
  15  *
  16  * This code is derived from software contributed to The NetBSD Foundation
  17  * by John F. Woods, jfw@funhouse.com.
  18  *
  19  * Redistribution and use in source and binary forms, with or without
  20  * modification, are permitted provided that the following conditions
  21  * are met:
  22  * 1. Redistributions of source code must retain the above copyright
  23  *    notice, this list of conditions and the following disclaimer.
  24  * 2. Redistributions in binary form must reproduce the above copyright
  25  *    notice, this list of conditions and the following disclaimer in the
  26  *    documentation and/or other materials provided with the distribution.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  29  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  30  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  31  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  32  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  33  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  34  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  35  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  36  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  37  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38  * POSSIBILITY OF SUCH DAMAGE.
  39  */
  40 #include <stddef.h>
  41 #include <time.h>
  42 #include <stdio.h>
  43 #include "pppd.h"
  44
  45 /* this version string will be checked against pppd's version string when
  46  * this plugin is loaded.
  47 */
  48 char pppd_version[] = VERSION;
  49
  50 /*
  51  * Usage: to use this status plug as-is, add the lines:
  52 plugin status
  53 lcpstatus /var/run/ppp0.status
  54  * to your PPP options file (or add the appropriate options to your
  55  * pppd command line), where /var/run/ppp0.status can vary to taste.
  56  * This plugin will then proceed to create the lcp status file and
  57  * write one of four strings to the file based on the most recent LCP
  58  * event:  "up", "down", "?", or "!", representing LCP up, LCP down,
  59  * LCP echo not received, and received-our-own-LCP-echo (probably
  60  * indicating a loopback or a disconnected modem echoing back characters).
  61  * On my system, I have a separate program which reads that file every
  62  * second and sends a UDP broadcast packet on my ethernet with the contents
  63  * of the file; each of the other computers on my ethernet (all Macs) have
  64  * a tiny little program which listens for that UDP broadcast packet and
  65  * updates a menubar status indicator; the end result is that when PPP
  66  * shuts down, users on my LAN immediately know without having to go look
  67  * at the modem.  (Or without demanding that *I* go look at the modem...)
  68  *
  69  * If you want to modify this plugin, other ways you could use and display
  70  * the data generated by the transitions would include:
  71  * + directly broadcasting the results from inside the pppd task (rather
  72  *   than having a separate process do it)
  73  * + store the ppp state in an SNMP database so it could be displayed with
  74  *   a standard form of client rather than a goofy little Mac OS X menubar
  75  *   widget.
  76  */
  77
  78 static char *statusfilename = 0;
  79 static char *laststatus = 0;
  80 static char UP[] = "up";
  81 static char DOWN[] = "down";
  82 static char MISS[] = "?";
  83 static char MINE[] = "!";
  84
  85 static option_t status_options[] = {
  86         { "lcpstatus", o_string, &statusfilename,
  87           "Name of file to which LCP status string will be written" },
  88         { NULL }
  89 };
  90
  91 /* status should be one of the canned constants above. */
  92 static void writestatus(char *status)
  93 {
  94         FILE *statusfile;
  95         if (status == laststatus) return;  /* we knew that already */
  96         statusfile = fopen(statusfilename, "w");
  97         if (!statusfile) {
  98                 warn("can't write %s to log LCP status", statusfilename);
  99                 free(statusfilename);
 100                 statusfilename = 0;
 101                 return;
 102         }
 103         fprintf(statusfile, "%s\n", status);
 104         fclose(statusfile);
 105         laststatus = status;
 106 }
 107
 108 static void status_lcp_up(void)
 109 {
 110         if (!statusfilename) return; /* not enabled */
 111         writestatus(UP);
 112 }
 113
 114 static void status_lcp_down(void)
 115 {
 116         if (!statusfilename) return; /* not enabled */
 117         writestatus(DOWN);
 118 }
 119
 120 static void status_lcp_echo(int pending)
 121 {
 122         if (!statusfilename) return; /* not enabled */
 123         if (pending == 0)
 124                 writestatus(UP);
 125         else if (laststatus != MINE)
 126                 writestatus(MISS);
 127 }
 128
 129 static void status_lcp_echoreply(int mine)
 130 {
 131         if (!statusfilename) return; /* not enabled */
 132         if (mine == 0)
 133                 writestatus(UP);
 134         else
 135                 writestatus(MINE);
 136 }
 137
 138 void plugin_init(void)
 139 {
 140         info("Initialize PPP status plugin.");
 141         add_options(status_options);
 142         lcp_up_hook = status_lcp_up;
 143         lcp_down_hook = status_lcp_down;
 144         lcp_echo_hook = status_lcp_echo;
 145         lcp_echoreply_hook = status_lcp_echoreply;
 146 }