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      1 /*	NetBSD: status.c,v 1.3 2008/05/04 13:30:54 martin 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 (at) 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 (at) 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 }
    147