#!/usr/bin/perl
# Make sure the above line correctly points to Perl on your workstation.  Use
#  "which perl" to find it.

###############################################################################
# ppps v1.0
# 1999 Digital Objects Software (http://mrdo.com)
# Created 04/24/99
# GNU copyright rules apply.
###############################################################################
#
# This program scans your /var/log/messages file for the latest successful
# ppp connection and reports the negotiated connection speed and assigned
# IP address.
#
# Only the last successful connection is reported.  It does not determine
# whether the workstation is currently connected.  A useful place to use
# this script is in the ip-up.local script so that the connection rate is
# reported every time a connection is made.
#
###############################################################################
#
# INSTALLATION
#
# You may simply execute this script anytime you want to see the last
# successfully negotiated connection speed and IP address.  Or you can
# automate the report by following these steps.
#
# 1. Copy this script to a convenient directory that users will be able to
#    access.  For instance, /usr/local/ppps/ppps.pl.  Grant execution
#    priveledges to the script (chmod 755 ppps.pl).
#
# 2. Create a symbolic link to the script that users will use to execute
#    the script.  
#    For instance, ln -s /usr/local/ppps/ppps.pl /usr/local/bin/ppps
#    Grant execution priveledges to the link if necessary.
#
# 3. Read permission to /var/log/messages must be given to users that
#    will be using this script, otherwise this script cannot extract the
#    modem log data.  -rw-r--r-- is recommended (chmod 644 /var/log/messages).
#
# 4. To report the connection speed every time a connection is made, execute
#    this script from the /etc/ppp/ip-up.local file.  If creating the
#    ip-up.local file, grant execution priveledges.
#    Add this line to ip-up.local:
#      /usr/local/bin/ppps > /dev/console &
#
###############################################################################

# You may need to adjust several script constants to conform to your
# specific system.  The script scans to the last occurrence of the modem
# string "CONNECT" then skips past certain strings that you identify in
# the $IGNORE lists.
#
# The default logic of the script is based on this example case:
# <snip>
# Apr 24 09:34:05 p166 ifup-ppp: pppd started for ppp0 on /dev/cua0 at 115200
# Apr 24 09:34:06 p166 pppd[2113]: pppd 2.3.5 started by root, uid 0
# Apr 24 09:34:07 p166 chat[2115]: abort on (BUSY)
# Apr 24 09:34:07 p166 chat[2115]: abort on (ERROR)
# Apr 24 09:34:07 p166 chat[2115]: abort on (NO CARRIER)
# Apr 24 09:34:07 p166 chat[2115]: abort on (NO DIALTONE)
# Apr 24 09:34:07 p166 chat[2115]: abort on (Invalid Login)
# Apr 24 09:34:07 p166 chat[2115]: abort on (Login incorrect)
# Apr 24 09:34:07 p166 chat[2115]: send (ATZ^M)
# Apr 24 09:34:07 p166 chat[2115]: expect (OK)
# Apr 24 09:34:07 p166 chat[2115]: ATZ^M^M
# Apr 24 09:34:07 p166 chat[2115]: OK
# Apr 24 09:34:07 p166 chat[2115]:  -- got it 
# Apr 24 09:34:07 p166 chat[2115]: send (ATDT3263000^M)
# Apr 24 09:34:07 p166 chat[2115]: expect (CONNECT)
# Apr 24 09:34:07 p166 chat[2115]: ^M
# Apr 24 09:34:26 p166 chat[2115]: ATDT3263000^M^M
# Apr 24 09:34:26 p166 chat[2115]: CONNECT
# Apr 24 09:34:26 p166 chat[2115]:  -- got it 
# Apr 24 09:34:26 p166 chat[2115]: send (^M)
# Apr 24 09:34:26 p166 chat[2115]: timeout set to 5 seconds
# Apr 24 09:34:26 p166 chat[2115]: expect (~)
# Apr 24 09:34:26 p166 chat[2115]:  49333/ARQ/V90/LAPM/V42BIS^M
# Apr 24 09:34:28 p166 chat[2115]: ^M
# Apr 24 09:34:31 p166 chat[2115]: alarm
# Apr 24 09:34:31 p166 chat[2115]: send (^M)
# Apr 24 09:34:31 p166 pppd[2113]: Serial connection established.
# Apr 24 09:34:31 p166 chat[2115]: send (^M)
# Apr 24 09:34:32 p166 pppd[2113]: Using interface ppp0
# Apr 24 09:34:32 p166 pppd[2113]: Connect: ppp0 <--> /dev/cua0
# Apr 24 09:34:36 p166 pppd[2113]: Remote message: Login Succeeded
# Apr 24 09:34:36 p166 pppd[2113]: local  IP address 209.113.185.150
# Apr 24 09:34:36 p166 pppd[2113]: remote IP address 209.150.4.3
# <snip>
#
# With this output:
# 49333/ARQ/V90/LAPM/V42BIS
# local IP address 209.113.185.150

use strict;

# Typically '/var/log/messages'
my $MESSAGES_LOG = '/var/log/messages';

# If non-zero, only those portions of strings after this many ':' will be
# output.  A value of 0 will output the whole string.
my $SHIFT_COLUMNS = 3;

# Modem response string identifying successful connection.  
# Case sensitive, literal, and bounded by whitespace.
my $CONNECT = 'CONNECT';
# Substrings after $CONNECT to ignore.
my @CONNECT_IGNORE = ('got it', 'send', 'timeout', 'expect');
# Number of lines after ignored lines to output
my $CONNECT_LINES = 1;
# Additional lines will be output if non-zero
my $MORE = 1;
# Substrings after last output to ignore.
my @MORE_IGNORE = ('^M', 'alarm', 'send', 'established', 'interface', 'onnect', 'message');
# Number of lines after ignored lines to output
my $MORE_LINES = 1;

###############################################################################

sub ignore {
# Test given string for existence within strings in given list
    my($str, @lst) = @_;

    my $ignore;


    foreach $ignore (@lst) {
	# '^M' requires a special case.  The '^' will be intrepreted as a
	# regular expression term.  Escape it.
	if ( $ignore =~ /^\^/ ) {
	    $ignore = '\\' . $ignore;
	}

	if ( $str =~ /$ignore/ ) {
	    return 1;
	}
    }

    return 0;
}

###############################################################################

sub clean {
# chomp \n and remove all '^M'
    my($str) = @_;


    chomp($str);
    $str =~ s/\^M//g;

    return($str);
}

###############################################################################

sub shiftColumns {
## Shift off beginning of string up to the number of ':' specified
    my($str) = @_;

    my @lst;
    my $i;


    @lst = split(/:/, $str);
    for ($i = 0; $i < $SHIFT_COLUMNS; $i++) {
	shift(@lst);
    }
    
    $str = join('', @lst);

    return($str);
}

###############################################################################

my @messages;
my $line;
my $ignore;
my @lst1;
my $i;
my @report;


# Make sure the file exists where expected
unless ( -e $MESSAGES_LOG ) {
    die("$MESSAGES_LOG does not exist\n");
}

# $MESSAGES_LOG is normally -rw-------, but must be -rw-r--r-- (644) in order
# for normal users to access it.
unless ( open(MESSAGES, $MESSAGES_LOG) ) {
    warn("Could not access $MESSAGES_LOG: $!\n");
    warn("This file should have -rw-r--r-- access for non-priveleged users.\n");
    die("As root, type 'chmod 644 $MESSAGES_LOG'\n");
}

# Let's not read the whole file into memory, it could be very large.
# Instead, find each occurrence of $CONNECT, then read each line thereafter
# into memory.  Each time $CONNECT is found, reset the buffer before reading
# the following lines.  That way, when the last $CONNECT has been passed and
# EOF reached, the buffer will contain the latest data pertaining to the
# latest session.

# First, find the first occurrence of the whitespace bounded $CONNECT
while ( $line = <MESSAGES> ) {
    if ( $line =~ /\s$CONNECT\s/ ) {
	last;
    }
}
unless ( $line =~ /\s$CONNECT\s/ ) {
    close(MESSAGES);
    die("String token $CONNECT was not found\n");
}

# Now find each successive $CONNECT, resetting the buffer each time, until
# end of file.
@messages = ();
while ( $line = <MESSAGES> ) {
    push(@messages, $line);
    # If $CONNECT is found, clear the buffer and continue with the next line
    if ( $line =~ /\s$CONNECT\s/ ) {
	@messages = ();
    }
}
# EOF
close(MESSAGES);

# @messages now contains all lines after last $CONNECT, if any.
# Parse through @messages, ignoring specified lines until the connection
# rate is found.
# @messages is shifted for each line processed to make it more efficient to
# parse subsequent lines.  A working copy of @messages is made for parsing
# because you cannot shift an array as you're iterating it (an internal copy
# must be made for the foreach iteration).
@report = ();
@lst1 = @messages;
foreach $line (@lst1) {
    unless ( ignore($line, @CONNECT_IGNORE) ) {
	# Get the number of $CONNECT_LINES wanted
	for ($i = 0; $i < $CONNECT_LINES && @messages > 0; $i++) {
	    $line = clean($line);
	    push(@report, $line);
	    # Continue shifting off each line
	    shift(@messages);
	}
	# Go on to $MORE
	last;
    }
    # Shift off each ignored line.  Shrinking the list like this will allow
    # us to start from the top when finding more lines after $CONNECT
    shift(@messages);
}

# Do $MORE if enabled
if ($MORE) {
    @lst1 = @messages;
    foreach $line (@lst1) {
	unless ( ignore($line, @MORE_IGNORE) ) {
	    # Get the number of $MORE_LINES wanted
	    for ($i = 0; $i < $CONNECT_LINES && @messages > 0; $i++) {
		$line = clean($line);
		push(@report, $line);
		# Continue shifting off each line
		shift(@messages);
	    }
	    # Done parsing log file
	    last;
	}
    }
    # Shift off each ignored line
    shift(@messages);
}

# Output results
if (@report) {
    foreach $line (@report) {
	# Shift number of columns specified.
	# Example:
	# 'Apr 24 09:34:26 p166 chat[2115]:  49333/ARQ/V90/LAPM/V42BIS'
	# '  49333/ARQ/V90/LAPM/V42BIS'
	if ($SHIFT_COLUMNS) {
	    $line = shiftColumns($line);
	}

	# Trim whitespace from beginning of string
	# Example:
	# '  49333/ARQ/V90/LAPM/V42BIS'
	# '49333/ARQ/V90/LAPM/V42BIS'
	$line =~ s/^\s+//;

	# Replace multiple whitespace with single space
	# Example:
	# 'local  IP address 209.113.185.150'
	# 'local IP address 209.113.185.150'
	$line =~ s/\s+/ /g;

	print "$line\n";
    }
}
else {
    die("No successful PPP connections were found\n");
}