rwh@aesat.UUCP (Russell Herman) (04/03/84)
...___>
.\" %M% %I% %E%
.TH UNETpaths 8
.SH NAME
UNETpaths - derive routes to USENET sites
.SH SYNOPSIS
UNETpaths [-o result] [-c cut_script] [-d basedir] -t
.SH DESCRIPTION
This script generates reasonably short (but not optimally short) paths from
your site to other sites on USENET. It does this by examining the paths
taken by those messages which have been received by your site.
.PP
Options are
.TP
.B \-o
This is the file that receives the results (default NETPATHS).
The paths in it are merged with those derived from the current net traffic,
thus providing a cumulative store of information. The syntax of each entry is
.ce 1
<dest_node> <path>
Entries may be added manually to this file if desired.
The first time this shell is executed, it is recommended that this file
be initialized to contain entries for all your possible 1-hops if you
are a relay, or 2-hops if you are a leaf. Obviously, since this is a
primitive learning program, the more initial information given, the
better the results are likely to be.
.TP
.B \-c
This file is used when links or entire nodes are deleted from the network.
It is, in fact an
.IR awk (1)
script. Two lines compose each cut_script entry. To delete the path A!B,
include the entries
.nf
/A!B!/{next}
/A!B$/{next}
.fi
To delete node A, use
.nf
/!A!/{next}
/!A$/{next}
.fi
The last line of the script must be
.nf
{print $0}
.fi
The default is not to use a cut script. Notice that when a net change
occurs, it is not sufficient to apply the relevant cuts for only one
.I UNETpaths
invocation. Until every item containing that path has been removed by
the expiry cleanup function, that path will be rederived. A period of
a couple months should probably allowed for the life of each cut script
entry.
.TP
.B \-d
This restricts examination of messages to a subdirectory of /usr/spool/new/net.
E.g, "-d jokes/d" would look only at "net.jokes.d" for routes. Normally, the
entire contents of /usr/spool/new/net is examined.
.TP
.B \-t
This flag indicates test mode. Numerous scratch files are built in /tmp;
in test mode, they will not be removed on completion.
.SH FILES
/etc/UNET/UNET.thishost - your site id
.SH SEE ALSO
.SH AUTHOR
Russ Herman (aesat!rwh)
.SH DIAGNOSTICS
self-explanatory
.SH BUGS
None known.
.SH CHANGES
Initial Release
------------------------------------------------------------------------------
basedir=/usr/spool/news/net
oldpath=NETPATHS
mysite=`cat /etc/UNET/UNET.thishost`
cuts=
tst=n
t=/tmp/$$?
ta=/tmp/$$a
tb=/tmp/$$b
tc=/tmp/$$c
td=/tmp/$$d
te=/tmp/$$e
ty=/tmp/$$y
tz=/tmp/$$z
while test -n "$1"
do
case $1 in
-c) shift; cuts=$1;;
-d) shift; basedir=/usr/spool/news/net/$1;;
-o) shift; oldpath=$1;;
-t) tst=y;;
*) echo Usage: netpaths [-d searchdir] [-o result] [-c cut.awkin] [-t] 1>&2; exit 1;;
esac
shift
done
if test -d $basedir; then
:
else
echo netpaths: $basedir not directory 1>&2; exit 1
fi
if test -f $oldpath; then
: merge the existing derived paths with the new
sed -e "s/ / !$mysite!/" $oldpath >$te
else
touch $te
fi
cat >$ta <<!
BEGIN{FS="!";k=2}
{if (NF < k+1) next
for (j=k; j<NF; j++) {
printf "%s ", \$j
printf "!$mysite"
for (i=k; i<=j; i++)
printf "!%s",\$i
printf "\n"
}
}
!
: collect raw data from net traffic
find $basedir -type f -exec awk "/^Path: $mysite!/{print \$0; exit}" {} \;|sort -u -o $tz
: the next stage generates one copy of every extant path, then
: minhops selects the one with the shortest number of hops to each destination
case :$cuts:$tst in
::n) awk -f $ta $tz|cat $te -|sort -u |minhops >$tb;;
:*:n) awk -f $ta $tz|cat $te -|awk -f $cuts -|sort -u |minhops >$tb;;
::y) awk -f $ta $tz|cat $te -|sort -u -o $ty
minhops <$ty >$tb;;
:*:y) awk -f $ta $tz|cat $te -|awk -f $cuts -|sort -u -o $ty
minhops <$ty >$tb;;
esac
: apply the minimum hop list to itself to shorten further
sort +2nr -3 $tb|awk "{printf \"/!$mysite!.*!%s/s//%s/\n\",\$1,\$2}" >$tc
: sed blows up when the pattern script is too long, so split it up
split -50 $tc $tc
list=`ls $tc??`
for i in $list
do
sed -f $i $tb >$td
mv $td $tb
done
rm -f $tc??
: end of sed kludge
awk "{print \$1 \" \" \$2}" $tb|sed -e "s/ !$mysite!/ /" >$oldpath
if test "$tst" = "n"; then
rm /tmp/$$?
fi
-------------------------------------------------------------------------------
/*$title minhops.c*/
/*M**************************************************************************
****************************************************************************
Program name: minhops.c
File name: minhops.c
Version: 1.3
Date: 84/03/29 11:04:55
Author: R. Herman (aesat!rwh)
Function:
Used in the netpaths procedure.
Takes a sorted list of records of the format
<dest> <path>
and outputs, for each <dest>, the record with the path
containing the fewest hops in the format
<dest> <path> <hop-count>
****************************************************************************
****************************************************************************/
static char sccs_id[] = {"@(#)minhops.c 1.3 84/03/29"};
#include <stdio.h>
struct rec {
int hopcnt;
char dest[17];
char path [513];
} s[2];
int base = 0;
/*$sttl main*/
main()
{
int eofsw;
char c, *pathp;
/* prime the input buffer */
if (scanf("%s %s", &s[1].dest[0], &s[1].path[0]) == EOF)
exit(0);
else {
s[1].hopcnt = 0;
pathp = &s[1].path[0];
while (c= *pathp++)
if (c == '!')
s[1].hopcnt++;
}
/* here to process next record */
while (EOF != scanf("%s %s", &s[base].dest[0], &s[base].path[0])) {
pathp = &s[base].path[0];
s[base].hopcnt = 0;
while (c= *pathp++)
if (c == '!')
s[base].hopcnt++;
if (strcmp(&s[base].dest[0], &s[1-base].dest[0])) {
printf("%s %s %d\n", &s[1-base].dest[0], &s[1-base].path[0],
s[1-base].hopcnt);
base = 1 - base;
}
else
if (s[base].hopcnt < s[1-base].hopcnt)
base = 1 - base;
}
printf("%s %s %d\n", &s[1-base].dest[0], &s[1-base].path[0],
s[1-base].hopcnt);
exit(0);
}
--
______
/ \ Russ Herman
@( [1;5m? ?[0m )@ 416-821-9190
( || ) {allegra,ihnp4,linus,decvax}!utzoo!aesat!rwh
( [5m\[m__[5m/[m ) AES Data Inc.
\____/ Mississauga, Ont. CANADA