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Diffstat (limited to 'usr.sbin/sendmail/contrib/doublebounce.pl')
| -rw-r--r-- | usr.sbin/sendmail/contrib/doublebounce.pl | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/usr.sbin/sendmail/contrib/doublebounce.pl b/usr.sbin/sendmail/contrib/doublebounce.pl new file mode 100644 index 00000000000..a853ec14f37 --- /dev/null +++ b/usr.sbin/sendmail/contrib/doublebounce.pl @@ -0,0 +1,232 @@ +#!/usr/bin/perl +# doublebounce.pl +# attempt to return a doubly-bounced email to a postmaster +# jr@terra.net, 12/4/97 +# +# invoke by creating an mail alias such as: +# doublebounce: "|/usr/local/sbin/doublebounce" +# then adding this line to your sendmail.cf: +# O DoubleBounceAddress=doublebounce +# +# optionally, add a "-d" flag in the aliases file, to send a +# debug trace to your own postmaster showing what is going on +# +# this allows the "postmaster" address to still go to a human being, +# while bounce messages can go to this script, which will bounce them +# back to the postmaster at the sending site. +# +# the algorithm is to scan the double-bounce error report generated +# by sendmail on stdin, for the original message (it starts after the +# second "Orignal message follows" marker), look for From, Sender, and +# Received headers from the point closest to the sender back to the point +# closest to us, and try to deliver a double-bounce report back to a +# postmaster at one of these sites in the hope that they can +# return the message to the original sender, or do something about +# the fact that that sender's return address is not valid. + + +use Socket; + +# look for debug flag +# +$dflag = 0; +$dflag = 1 if ($ARGV[0] eq "-d"); + +# get local host name +# you may need to edit these two lines for however your system does this +# +$host = `hostname`; chop($host); +$domain = `dnsdomainname`; chop($domain); + +# get temp file name +$tmp = "/tmp/doubb$$"; + +# save message from STDIN to a file +# I thought about reading it into a buffer here, but some messages +# are 10+Mb so a buffer may not be a good idea +# +if (! open(MSG, "+> $tmp")) { + # can't open temp file -- send message to local postmaster + # open(MAIL, "| /usr/sbin/sendmail -oeq postmaster"); + print MAIL <STDIN>; + close(MAIL); + exit(1); +} +print MSG <STDIN>; + +# scan message for list of possible sender sites +# note that original message appears after the second +# "Original message follows" marker +# look for From, Sender, and Reply-To and try them, too +# +$inhdr = 0; +$hdrs = 0; +$skip = 0; +seek(MSG, 0, 0); +while (<MSG>) { + chop; + if (/^ ----- Original message follows -----$/ + || /^ ----Unsent message follows----$/) { + $i = 0; + $inhdr = 1; + $hdrs++; + $skip = 1; + next; + } + if ($skip) { + $skip--; + next; + } + if (/^$/) { + last if ($hdrs >= 2); + $inhdr = 0; + next; + } + if (! $inhdr) { + next; + } + if (! /^[ \t]/) { $hdr[$i++] = $_ } + else { + $i--; + $hdr[$i++] .= $_; + } +} +$rcvd = 0; +for ($j = 0; $j < $i; $j++) { + print STDERR "DEBUG hdr[$j] = $hdr[$j]\n"; + if ($hdr[$j] =~ /^received:/i) { + ($addr[$rcvd++]) = $hdr[$j] =~ m/.*\sby\s([^\s]+)\s.*/; + } + if ($hdr[$j] =~ /^reply-to:/i) { + ($addr1{"reply-to"} = $hdr[$j]) =~ s/^reply-to: *//i; + } + if ($hdr[$j] =~ /^sender:/i) { + ($addr1{"sender"} = $hdr[$j]) =~ s/^sender: *//i; + } + if ($hdr[$j] =~ /^from:/i) { + ($addr1{"from"} = $hdr[$j]) =~ s/^from: *//i; + } +} + +# %addr and %addr1 arrays now contain lists of possible sites (or From headers). +# Go through them parsing for the site name, and attempting to send +# to the named person or postmaster@ each site in turn until successful +# +if ($dflag) { + open(DEBUG, "|/usr/sbin/sendmail postmaster"); + print DEBUG "Subject: double bounce dialog\n"; +} +$sent = 0; +# foreach $x ("from", "sender", "reply-to") { +foreach $x ("from", "sender") { + $y = &parseaddr($addr1{$x}); + if ($y) { + print DEBUG "Trying $y\n" if ($dflag); + if (&sendbounce("$y")) { + $sent++; + last; + } + $y =~ s/.*@//; + print DEBUG "Trying postmaster\@$y\n" if ($dflag); + if (&sendbounce("postmaster\@$y")) { + $sent++; + last; + } + } +} +if (! $sent) { + $rcvd--; + for ($i = $rcvd; $i >= 0; $i--) { + $y = &parseaddr($addr[$i]); + $y =~ s/.*@//; + if ($y) { + print DEBUG "Trying postmaster\@$y\n" if ($dflag); + if (&sendbounce("postmaster\@$y")) { + $sent++; + last; + } + } + } +} +if (! $sent) { + # queer things are happening to me + # $addr[0] should be own domain, so we should have just + # tried postmaster@our.domain. theoretically, we should + # not get here... + if ($dflag) { + print DEBUG "queer things are happening to me\n"; + print DEBUG "Trying postmaster\n"; + } + &sendbounce("postmaster"); +} + +# clean up and get out +# +if ($dflag) { + seek(MSG, 0, 0); + print DEBUG "\n---\n"; print DEBUG <MSG>; + close(DEBUG); +} +close(MSG); +unlink("$tmp"); +exit(0); + + + + + +# parseaddr() +# parse hostname from From: header +# +sub parseaddr { + local($hdr) = @_; + local($addr); + + if ($hdr =~ /<.*>/) { + ($addr) = $hdr =~ m/<(.*)>/; + return $addr; + } + if ($addr =~ /\s*\(/) { + ($addr) = $hdr =~ m/\s*(.*)\s*\(/; + return $addr; + } + ($addr) = $hdr =~ m/\s*(.*)\s*/; + return $addr; +} + + +# sendbounce() +# send bounce to postmaster +# +# this re-invokes sendmail in immediate and quiet mode to try +# to deliver to a postmaster. sendmail's exit status tells us +# wether the delivery attempt really was successful. +# +sub sendbounce { + local($dest) = @_; + local($st); + + open(MAIL, "| /usr/sbin/sendmail -ocn -odi -oeq $dest"); + print MAIL <<EOT; +From: Mail Delivery Subsystem <mail-router\@$domain> +Subject: Postmaster notify: double bounce +Reply-To: nobody\@$domain +Errors-To: nobody\@$domain +Precedence: junk +Auto-Submitted: auto-generated (postmaster notification) + +The following message was received at $host.$domain for an invalid +recipient. The sender's address was also invalid. Since the message +originated at or transited through your mailer, this notification is being +sent to you in the hope that you will determine the real originator and +have them correct their From or Sender address. + +The invalid sender address was: $addr1{"from"}. + + ----- The following is a double bounce at $host.$domain ----- + +EOT + seek(MSG, 0, 0); + print MAIL <MSG>; + return close(MAIL); +} |