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|
# pm-janslookup.rc -- run nslookup on variable INPUT
#
# File id
#
# Copyright (C) 1997-2010 Jari Aalto
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details at
# <http://www.gnu.org/copyleft/gpl.html>.
#
# Description
#
# This subroutine runs `nslookup' on given INPUT address. This may be
# an effective way to test if the address is known to Internet. You
# could use this information to determine if some automated reply to
# a address can be sent. The know truth is that you can't validate
# whole email address
#
# to_someone@foo.com
#
# but you can validate "foo.com"; that's the closest you get.
#
# [Warning: If you don't use cache feature...]
#
# Do not however use this module to regularly check _all_ incoming
# from addresses with this subroutine for possible bogus UBE
# addresses, because calling nslookup
#
# o may be slow, building to connection and querying the results
# may take several seconds. (some times, usually it's quote fast)
# o consumes quite a lot resources.
#
# You can however check _some_ messages that are likely UBE to verify
# your doubts.
#
# Required settings
#
# PMSRC must point to source directory of procmail code. This subroutine
# will include
#
# o pm-javar.rc
# o pm-jaaddr.rc
#
# Call arguments (variables to set before calling)
#
# o INPUT, the address (only strict domain part) which is checked.
# Eg. "this.domain.com". See examples for more.
# If this string contains "@" character, then additional
# subroutine pm-jaaddr.rc is called to extraxt the domain name
# INPUT = "John Doe <foo@site.com>" --> INPUT = "site.com"
# o JA_NSLOOKUP_CACHE, filename. If exists, cache is used and updated.
# o JA_NSLOOKUP_FORCE, if "yes", then cache is not used but a forced
# nslookup is performed.
# o JA_NSLOOKUP_OPT, is currently empty, but you could see if you
# you want to use "-querytype=MX". However this option may give
# you response: "No mail exchanger (MX) records available",
# which is flagged as nslookup failure.
# o JA_NSLOOKUP_SERVER, optional, the server to user for nslookup
#
# If the cache file can be read:
#
# o Each entry has format "address.com ns-error". The error
# indication is added to the line if the nslookup failed when
# address was checked. Otherwise line contains "address.com".
# o The cache is always checked first. If there is no entry matching
# the current address, only then is nslookup called and new entry
# added to cache.
#
# Return values
#
# o Variable ERROR will be set to "yes" if nslookup failed or
# to "no" if nslookup succeeded. It can also contain "maybe" if
# nslookup returned "No address (A) records available"
# o ERROR_MATCH contains one line lookup failure reason.
#
# Following conditions trigger "maybe" and no "ns-error" is written
# into the cache.
#
# o "No address (A) records available for xxx"
#
# Usage example
#
# If you are going to check some header field, like From:, please
# explode the content with pm-jaaddr.rc first. Suppose you have
# string:
#
# "From: foo@ingrid.sps.mot.com (Yoshiaki foo)"
#
# You have to derive the address from string and pass the site name:
# Read From: field and address from it.
#
# PMSRC = $HOME/pm
# RC_NSLOOKUP = $PMSRC/pm-janslookup.rc # name the subroutine
#
# :0
# * MAYBE_UBE ?? yes
# * ^From:\/.*
# {
# INPUT = $MATCH
# INCLUDERC = $RC_NSLOOKUP # to nslookup
#
# :0
# * ERROR ?? yes
# {
# # Hm, nslookup failed, can't send anything back to this
# # address
# }
# }
#
# Second example, check if the address is reachable before sending reply
#
# INPUT = `$FORMAIL -rt -x To:`
# INCLUDERC = $RC_NSLOOKUP
#
# :0
# * ERROR ?? no
# {
# # okay, at least site address seems to be reachable
# }
#
#
# Change Log (none)
# .................................................... &initialising ...
dummy = "
========================================================================
pm-janslookup.rc: init: INPUT = $INPUT"
:0
* ! WSPC ?? [ ]
{
INCLUDERC = $PMSRC/pm-javar.rc
}
# If user gave string that had Email, explode it automatically
# INPUT = "John doe <foo@site.com>" --> "site.com"
:0
* INPUT ?? @
{
INCLUDERC = $PMSRC/pm-jaaddr.rc # - explode INPUT string
INPUT = $SITE # - the address is only fed
}
# ...................................................... &input-vars ...
# o INPUT contains the address to check
# o JA_NSLOOKUP_CACHE is optional
# Set to empty "" if you don't wan't to use cache in some particular
# cases
JA_NSLOOKUP_CACHE = ${JA_NSLOOKUP_CACHE:-"$HOME/.nslookup.cache"}
# other options
JA_NSLOOKUP_FORCE = ${JA_NSLOOKUP_FORCE:-"no"}
JA_NSLOOKUP_OPT = ${JA_NSLOOKUP_OPT:-"-querytype=MX"}
JA_NSLOOKUP_SERVER = ${JA_NSLOOKUP_SERVER:-""}
NSLOOKUP = ${NSLOOKUP:-"nslookup"} # Add `-silent' in Linux
TOUCH = ${TOUCH:-"touch"} # binary to create cache file
# ..................................................... &output-vars ...
# output variables
ERROR = "yes"
ERROR_MATCH
# ........................................................... &do-it ...
# ErrorWord is not really ment for user configurable, but
# as you can see, it is coded that way in case you would like to
# use some other error word.
ErrorWord = ${ErrorWord:-"nlookup-error"}
dummy = "pm-janslookup.rc: do the work"
# The string must have one dot somewhere, otherwise it is not a domain
:0
*$ INPUT ?? $NSPC+\.$NSPC+
{
topDomain = "xxx-dummy-regexp"
cache = "no"
entry = "no"
:0
* INPUT ?? ()\/[^.]+\.[^.]+^^
{
topDomain = $MATCH # xxx.foo.com --> foo.com
}
# If variable is not empty, suppose that user wants to use cache
:0
* ! JA_NSLOOKUP_CACHE ?? ^^^^
* JA_NSLOOKUP_FORCE ?? no
{
cache = "yes"
:0 hwic # Create file if it doesn't exist.
* ! ? $IS_EXIST $JA_NSLOOKUP_CACHE
| $TOUCH $JA_NSLOOKUP_CACHE
}
dummy = "pm-janslookup.rc: Test if cache is in use"
:0
* cache ?? yes
*$ ? $IS_READABLE $JA_NSLOOKUP_CACHE
{
# Convert regexp to "safe" format, escapeping regexp
# metacharacters. See pm-tips.txt
regexp = "$\INPUT"
:0 # kill leading "()"
* regexp ?? ^^\(\)\/.*
{
regexp = "$MATCH"
}
# b) search hostname and SPACE like in: "this.site.com nlookup-error"
# a) or "this.site.com"
line = `$EGREP "^$regexp( | *$)" $JA_NSLOOKUP_CACHE`
:0 # was this address in cache?
*$ line ?? $INPUT
{
entry = "yes"
}
dummy = "pm-janslookup.rc: Test if cache line does _not_ include $ErrorWord"
:0
* entry ?? yes
*$ ! line ?? $ErrorWord
{
ERROR = "no"
}
}
# Cache is not used OR there was no line in the cache
dummy = "pm-janslookup.rc: Test if we call nslookup"
:0
* entry ?? no
{
stat = `$NSLOOKUP $JA_NSLOOKUP_OPT "$INPUT" $JA_NSLOOKUP_SERVER`
# If nslookup succeeds, at least HP-UX 9/10, ULTRIX and SUN
# return some of these choices upon success:
#
# Non-authoritative answer:
# Name: uta.fi
#
# Or
#
# Non-authoritative answer:
# geocities.com preference = 0, mail exchanger = ...
#
# Or
#
# Name: foo.com
# Address: 209.54.94.60
#
# Or
#
# Authoritative answers can be found from:
# foo.com
# origin = xx.foo.com
#
# Or
# Non-authoritative answer:
# foo.com mail exchanger = 0 mx1.foo.com.
#
# Or ^($)$topDomain
#
# This needs some explaining. When procmail captures
# the `nslookup' command it does it wrong for some unknown reason
# for some mail hosts. The captured output is:
#
# procmail: Assigning "stat=Name Server: zeus.tele.nokia.fi
# Address: 131.228.134.50
#
# umd.umich.edu
# origin = tiamat.umd.umich.edu
# mail addr = hostmaster.tiamat.umd.umich.edu
# serial = 970727
# refresh = 28800 (8 hours)
# retry = 14400 (4 hours)
# expire = 2419200 (28 days)
# minimum ttl = 14400 (4 hours)"
#
# notice? The line "Authoritative answers can be found from:"
# is not there while it is if I run the same command is
# run from command line.
# |Authoritative answers can be found from:($).*
:0
* stat ?? ()\/No +address.*available.*
{
# *** No address information is available for ...
ERROR_MATCH = $MATCH
ERROR = "yes"
}
:0 E
*$ stat ?? ()\/answer:($)(Name:)? *$INPUT\
|(Name: *$INPUT)|from:($) +$topDomain\
|($) *$topDomain
{
ERROR = "no"
}
# ............................................. Linux/Cygwin ...
# Win32/Cygwin nslookup returns this answer
# prompt> nslookup -querytype=MX cs2.tpu.fi
#
# Non-authoritative answer:
# Server: nsX.koti.tpo.fi
# Address: 212.63.10.250
#
# cs2.tpu.fi MX preference = 0, mail exchanger = xxx.tpu.fi
# cs2.tpu.fi MX preference = 10, mail exchanger = yyy.tpu.fi
# cs2.tpu.fi MX preference = 20, mail exchanger = zzz.funet.fi
#
# fi nameserver = HYDRA.HELSINKI.fi
# fi nameserver = NS-SE.ELISA.NET
# fi nameserver = PRIFI.FICORA.fi
# fi nameserver = NS1-FIN.GLOBAL.SONERA.fi
# fi nameserver = T.NS.VERIO.NET
# fi nameserver = NS.UU.NET
# xxx.tpu.fi internet address = 193.167.70.45
# yyy.tpu.fi internet address = 193.167.70.20
# mail.funet.fi internet address = 193.166.0.98
# mail.funet.fi internet address = 193.166.0.97
# HYDRA.HELSINKI.fi internet address = 128.214.4.29
# PRIFI.FICORA.fi internet address = 193.229.4.44
dummy="Win32/Cygwin nslookup check"
:0
*$ stat ?? internet address = .*$topDomain
{
ERROR = "no"
}
# .................................................. message ...
msg = ""
:0
* ERROR ?? yes
{
msg = $ErrorWord
}
:0
* ERROR ?? maybe
{
msg = "maybe"
}
# .............................................. write cache ...
dummy = "pm-janslookup.rc: Test if '$INPUT' should be added to cache"
:0 hwic:
* cache ?? yes
| echo "$INPUT $msg" >> $JA_NSLOOKUP_CACHE
}
}
:0 E
{
dummy = "pm-janslookup.rc: $JA_MSG_ERROR invalid INPUT"
}
dummy = "pm-janslookup.rc: end: input: $INPUT error: $ERROR"
# end of file pm-janslokup.rc
|
