From 26356ea07835de641f1606d7a3cec082abd2856a Mon Sep 17 00:00:00 2001
From: Tom Krizek <tkrizek@isc.org>
Date: Tue, 6 Feb 2024 15:35:49 +0100
Subject: [PATCH] Use a single local port for ditch.pl

The ditch.pl script is used to generate burst traffic without waiting
for the responses. When running other tests in parallel, this can result
in a ephemeral port clash, since the ditch.pl process closes the socket
immediately. In rare occasions when the message ID also clashes with
other tests' queries, it might result in an UnexpectedSource error from
dnspython.

Use a dedicated port EXTRAPORT8 which is reserved for each test as a
source port for the burst traffic.

(cherry picked from commit 339fa5690a5d80deb287ad119dd8f900c38545a1)
---
 bin/tests/system/ditch.pl             | 15 +++++++++++----
 bin/tests/system/fetchlimit/tests.sh  |  2 +-
 bin/tests/system/serve-stale/tests.sh |  2 +-
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/bin/tests/system/ditch.pl b/bin/tests/system/ditch.pl
index e2082503d7..f77d02224d 100644
--- a/bin/tests/system/ditch.pl
+++ b/bin/tests/system/ditch.pl
@@ -34,12 +34,12 @@ use IO::File;
 use IO::Socket;
 
 sub usage {
-    print ("Usage: ditch.pl [-s address] [-p port] [file]\n");
+    print ("Usage: ditch.pl [-s address] [-p port] [-b source_port] [file]\n");
     exit 1;
 }
 
 my %options={};
-getopts("s:p:t:", \%options);
+getopts("s:p:b:", \%options);
 
 my $addr = "127.0.0.1";
 $addr = $options{s} if defined $options{s};
@@ -47,6 +47,9 @@ $addr = $options{s} if defined $options{s};
 my $port = 53;
 $port = $options{p} if defined $options{p};
 
+my $source_port = 0;
+$source_port = $options{b} if defined $options{b};
+
 my $file = "STDIN";
 if (@ARGV >= 1) {
     my $filename = shift @ARGV;
@@ -74,8 +77,12 @@ while (defined(my $line = <$file>) ) {
     $packet->header->rd(1);
     $packet->push(question => $q);
 
-    my $sock = IO::Socket::INET->new(PeerAddr => $addr, PeerPort => $port,
-                                     Proto => "udp",) or die "$!";
+    my $sock = IO::Socket::INET->new(
+        PeerAddr => $addr,
+        PeerPort => $port,
+        Proto => "udp",
+        LocalPort => $source_port,
+        ) or die "$!";
 
     my $bytes = $sock->send($packet->data);
     #print ("sent $bytes bytes to $addr:$port:\n");
diff --git a/bin/tests/system/fetchlimit/tests.sh b/bin/tests/system/fetchlimit/tests.sh
index 6e3f7494fe..44818c8a5f 100644
--- a/bin/tests/system/fetchlimit/tests.sh
+++ b/bin/tests/system/fetchlimit/tests.sh
@@ -35,7 +35,7 @@ burst() {
       echo "${num}${2}${3}.lamesub.example A" >>burst.input.$$
     fi
   done
-  $PERL ../ditch.pl -p ${PORT} -s ${server} burst.input.$$
+  $PERL ../ditch.pl -p ${PORT} -s ${server} -b ${EXTRAPORT8} burst.input.$$
   rm -f burst.input.$$
 }
 
diff --git a/bin/tests/system/serve-stale/tests.sh b/bin/tests/system/serve-stale/tests.sh
index da54c3a4db..b9e5888f10 100755
--- a/bin/tests/system/serve-stale/tests.sh
+++ b/bin/tests/system/serve-stale/tests.sh
@@ -2500,7 +2500,7 @@ burst() {
     num=$((num - 1))
     echo "fetch${num}.example A" >>burst.input.$$
   done
-  $PERL ../ditch.pl -p ${PORT} -s 10.53.0.3 burst.input.$$
+  $PERL ../ditch.pl -p ${PORT} -s 10.53.0.3 -b ${EXTRAPORT8} burst.input.$$
   rm -f burst.input.$$
 }