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Merge branch 'ondrej/serve-stale-improvements' into 'main'

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Serve-stale improvements

Closes #1712 and #1829

See merge request isc-projects/bind9!3872
This commit is contained in:
Matthijs Mekking 2020-08-04 12:17:57 +00:00
commit bf760383e8
19 changed files with 335 additions and 32 deletions
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7
CHANGES
View file

@ -1,3 +1,10 @@
5484. [func] Expire the 0 TTL RRSet quickly rather using them for
stale answers. [GL #1829]
5483. [func] Keeping "stale" answers in cache has been disabled by
default and can be re-enabled with a new configuration
option "stale-cache-enable". [GL #1712]
5482. [bug] BIND 9 would fail to bind to IPv6 addresses in a
tentative state when a new IPv6 address was added to the
system, but the Duplicate Address Detection (DAD)

1
bin/named/config.c
View file

@ -196,6 +196,7 @@ options {\n\
# sortlist <none>\n\
stale-answer-enable false;\n\
stale-answer-ttl 1; /* 1 second */\n\
stale-cache-enable false;\n\
synth-from-dnssec no;\n\
# topology <none>\n\
transfer-format many-answers;\n\

2
bin/named/named.conf.rst
View file

@ -401,6 +401,7 @@ OPTIONS
stacksize ( default | unlimited | sizeval );
stale-answer-enable boolean;
stale-answer-ttl duration;
stale-cache-enable boolean;
startup-notify-rate integer;
statistics-file quoted_string;
synth-from-dnssec boolean;
@ -785,6 +786,7 @@ VIEW
sortlist { address_match_element; ... };
stale-answer-enable boolean;
stale-answer-ttl duration;
stale-cache-enable boolean;
synth-from-dnssec boolean;
transfer-format ( many-answers | one-answer );
transfer-source ( ipv4_address | * ) [ port ( integer | * ) ] [

15
bin/named/server.c
View file

@ -3895,7 +3895,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
uint32_t max_cache_size_percent = 0;
size_t max_adb_size;
uint32_t lame_ttl, fail_ttl;
uint32_t max_stale_ttl;
uint32_t max_stale_ttl = 0;
dns_tsig_keyring_t *ring = NULL;
dns_view_t *pview = NULL; /* Production view */
isc_mem_t *cmctx = NULL, *hmctx = NULL;
@ -4358,9 +4358,18 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
view->synthfromdnssec = cfg_obj_asboolean(obj);
obj = NULL;
result = named_config_get(maps, "max-stale-ttl", &obj);
result = named_config_get(maps, "stale-cache-enable", &obj);
INSIST(result == ISC_R_SUCCESS);
max_stale_ttl = ISC_MAX(cfg_obj_asduration(obj), 1);
if (cfg_obj_asboolean(obj)) {
obj = NULL;
result = named_config_get(maps, "max-stale-ttl", &obj);
INSIST(result == ISC_R_SUCCESS);
max_stale_ttl = ISC_MAX(cfg_obj_asduration(obj), 1);
}
/*
* If 'stale-cache-enable' is false, max_stale_ttl is set to 0,
* meaning keeping stale RRsets in cache is disabled.
*/
obj = NULL;
result = named_config_get(maps, "stale-answer-enable", &obj);

1
bin/tests/system/serve-stale/ns1/named1.conf.in
View file

@ -30,6 +30,7 @@ options {
max-stale-ttl 3600;
stale-answer-ttl 2;
stale-answer-enable yes;
stale-cache-enable yes;
servfail-ttl 0;
};

1
bin/tests/system/serve-stale/ns1/named2.conf.in
View file

@ -30,6 +30,7 @@ options {
max-stale-ttl 20;
stale-answer-ttl 3;
stale-answer-enable yes;
stale-cache-enable yes;
servfail-ttl 0;
};

2
bin/tests/system/serve-stale/ns3/named.conf.in
View file

@ -28,7 +28,7 @@ options {
listen-on-v6 { none; };
recursion yes;
dump-file "named_dump3.db";
// This configuration has no serve-stale options set.
stale-cache-enable yes;
};
zone "." {

1
bin/tests/system/serve-stale/ns4/named.conf.in
View file

@ -29,6 +29,7 @@ options {
recursion yes;
dump-file "named_dump4.db";
stale-answer-enable no;
stale-cache-enable yes;
};
zone "." {

40
bin/tests/system/serve-stale/ns5/named.conf.in Normal file
View file

@ -0,0 +1,40 @@
/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
key rndc_key {
secret "1234abcd8765";
algorithm hmac-sha256;
};
controls {
inet 10.53.0.5 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
};
options {
query-source address 10.53.0.5;
notify-source 10.53.0.5;
transfer-source 10.53.0.5;
port @PORT@;
pid-file "named.pid";
listen-on { 10.53.0.5; };
listen-on-v6 { none; };
recursion yes;
dump-file "named_dump5.db";
stale-answer-enable yes;
stale-cache-enable no;
max-cache-ttl 24h;
};
zone "." {
type secondary;
primaries { 10.53.0.1; };
file "root.bk";
};

1
bin/tests/system/serve-stale/setup.sh
View file

@ -16,3 +16,4 @@ $SHELL clean.sh
copy_setports ns1/named1.conf.in ns1/named.conf
copy_setports ns3/named.conf.in ns3/named.conf
copy_setports ns4/named.conf.in ns4/named.conf
copy_setports ns5/named.conf.in ns5/named.conf

250
bin/tests/system/serve-stale/tests.sh
View file

@ -84,7 +84,7 @@ $RNDCCMD 10.53.0.1 stats > /dev/null 2>&1
[ -f ns1/named.stats ] || ret=1
cp ns1/named.stats ns1/named.stats.$n
# Check first 10 lines of Cache DB statistics. After prime queries, we expect
# two active TXT one nxrrset TXT, and one NXDOMAIN.
# two active TXT, one active Others, one nxrrset TXT, and one NXDOMAIN.
grep -A 10 "++ Cache DB RRsets ++" ns1/named.stats.$n > ns1/named.stats.$n.cachedb || ret=1
grep "1 Others" ns1/named.stats.$n.cachedb > /dev/null || ret=1
grep "2 TXT" ns1/named.stats.$n.cachedb > /dev/null || ret=1
@ -500,7 +500,7 @@ $RNDCCMD 10.53.0.1 stats > /dev/null 2>&1
[ -f ns1/named.stats ] || ret=1
cp ns1/named.stats ns1/named.stats.$n
# Check first 10 lines of Cache DB statistics. After prime queries, we expect
# two active TXT RRsets, one nxrrset TXT, and one NXDOMAIN.
# two active TXT RRsets, one active Others, one nxrrset TXT, and one NXDOMAIN.
grep -A 10 "++ Cache DB RRsets ++" ns1/named.stats.$n > ns1/named.stats.$n.cachedb || ret=1
grep "2 TXT" ns1/named.stats.$n.cachedb > /dev/null || ret=1
grep "1 Others" ns1/named.stats.$n.cachedb > /dev/null || ret=1
@ -703,7 +703,7 @@ $RNDCCMD 10.53.0.3 stats > /dev/null 2>&1
[ -f ns3/named.stats ] || ret=1
cp ns3/named.stats ns3/named.stats.$n
# Check first 10 lines of Cache DB statistics. After prime queries, we expect
# two active TXT RRsets, one nxrrset TXT, and one NXDOMAIN.
# two active TXT RRsets, one active Others, one nxrrset TXT, and one NXDOMAIN.
grep -A 10 "++ Cache DB RRsets ++" ns3/named.stats.$n > ns3/named.stats.$n.cachedb || ret=1
grep "2 TXT" ns3/named.stats.$n.cachedb > /dev/null || ret=1
grep "1 Others" ns3/named.stats.$n.cachedb > /dev/null || ret=1
@ -861,7 +861,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
#
# Now test server with serve-stale disabled.
# Now test server with serve-stale answers disabled.
#
echo_i "test server with serve-stale disabled"
@ -875,7 +875,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache longttl.example (serve-stale disabled) ($n)"
echo_i "prime cache longttl.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 longttl.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
@ -884,7 +884,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache data.example (serve-stale disabled) ($n)"
echo_i "prime cache data.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 data.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
@ -894,7 +894,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache othertype.example (serve-stale disabled) ($n)"
echo_i "prime cache othertype.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 othertype.example CAA > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
@ -904,7 +904,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache nodata.example (serve-stale disabled) ($n)"
echo_i "prime cache nodata.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 nodata.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
@ -914,7 +914,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache nxdomain.example (serve-stale disabled) ($n)"
echo_i "prime cache nxdomain.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 nxdomain.example TXT > dig.out.test$n
grep "status: NXDOMAIN" dig.out.test$n > /dev/null || ret=1
@ -924,14 +924,14 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "verify prime cache statistics (serve-stale disabled) ($n)"
echo_i "verify prime cache statistics (serve-stale answers disabled) ($n)"
ret=0
rm -f ns4/named.stats
$RNDCCMD 10.53.0.4 stats > /dev/null 2>&1
[ -f ns4/named.stats ] || ret=1
cp ns4/named.stats ns4/named.stats.$n
# Check first 10 lines of Cache DB statistics. After prime queries, we expect
# two active TXT RRsets, one nxrrset TXT, and one NXDOMAIN.
# two active TXT RRsets, one active Others, one nxrrset TXT, and one NXDOMAIN.
grep -A 10 "++ Cache DB RRsets ++" ns4/named.stats.$n > ns4/named.stats.$n.cachedb || ret=1
grep "2 TXT" ns4/named.stats.$n.cachedb > /dev/null || ret=1
grep "1 Others" ns4/named.stats.$n.cachedb > /dev/null || ret=1
@ -972,7 +972,7 @@ waitfile dig.out.test$((n+3))
waitfile dig.out.test$((n+4))
n=$((n+1))
echo_i "check fail of data.example (serve-stale disabled) ($n)"
echo_i "check fail of data.example (serve-stale answers disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
@ -980,7 +980,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of othertype.example (serve-stale disabled) ($n)"
echo_i "check fail of othertype.example (serve-stale answers disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
@ -988,7 +988,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of nodata.example (serve-stale disabled) ($n)"
echo_i "check fail of nodata.example (serve-stale answers disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
@ -996,7 +996,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of nxdomain.example (serve-stale disabled) ($n)"
echo_i "check fail of nxdomain.example (serve-stale answers disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
@ -1004,7 +1004,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "verify stale cache statistics (serve-stale disabled) ($n)"
echo_i "verify stale cache statistics (serve-stale answers disabled) ($n)"
ret=0
rm -f ns4/named.stats
$RNDCCMD 10.53.0.4 stats > /dev/null 2>&1
@ -1024,7 +1024,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
# Dump the cache.
n=$((n+1))
echo_i "dump the cache (serve-stale disabled) ($n)"
echo_i "dump the cache (serve-stale answers disabled) ($n)"
ret=0
$RNDCCMD 10.53.0.4 dumpdb -cache > rndc.out.test$n 2>&1 || ret=1
done=0
@ -1049,7 +1049,7 @@ LASTWEEK=`TZ=UTC perl -e 'my $now = time();
printf("%04d%02d%02d%02d%02d%02d", $y+1900, $mo+1, $d, $h, $m, $s);'`
n=$((n+1))
echo_i "mock the cache date to $LASTWEEK (serve-stale disabled) ($n)"
echo_i "mock the cache date to $LASTWEEK (serve-stale answers disabled) ($n)"
ret=0
sed -E "s/DATE [0-9]{14}/DATE $LASTWEEK/g" ns4/named_dump4.db > ns4/named_dumpdb4.db.out || ret=1
cp ns4/named_dumpdb4.db.out ns4/named_dumpdb4.db
@ -1060,7 +1060,7 @@ echo_i "start ns4"
start_server --noclean --restart --port ${PORT} serve-stale ns4
n=$((n+1))
echo_i "verify ancient cache statistics (serve-stale disabled) ($n)"
echo_i "verify ancient cache statistics (serve-stale answers disabled) ($n)"
ret=0
rm -f ns4/named.stats
$RNDCCMD 10.53.0.4 stats #> /dev/null 2>&1
@ -1076,5 +1076,217 @@ grep "#NXDOMAIN" ns4/named.stats.$n.cachedb > /dev/null && ret=1
status=$((status+ret))
if [ $ret != 0 ]; then echo_i "failed"; fi
#
# Test the server with stale-cache disabled.
#
echo_i "test server with serve-stale cache disabled"
n=$((n+1))
echo_i "enable responses from authoritative server ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.2 txt enable > dig.out.test$n
grep "ANSWER: 1," dig.out.test$n > /dev/null || ret=1
grep "TXT.\"1\"" dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache longttl.example (serve-stale cache disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.5 longttl.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 1," dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache data.example (serve-stale cache disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.5 data.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 1," dig.out.test$n > /dev/null || ret=1
grep "data\.example\..*2.*IN.*TXT.*A text record with a 2 second ttl" dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache othertype.example (serve-stale cache disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.5 othertype.example CAA > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 1," dig.out.test$n > /dev/null || ret=1
grep "othertype\.example\..*2.*IN.*CAA.*0.*issue" dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache nodata.example (serve-stale cache disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.5 nodata.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
grep "example\..*2.*IN.*SOA" dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache nxdomain.example (serve-stale cache disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.5 nxdomain.example TXT > dig.out.test$n
grep "status: NXDOMAIN" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
grep "example\..*2.*IN.*SOA" dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "verify prime cache statistics (serve-stale cache disabled) ($n)"
ret=0
rm -f ns5/named.stats
$RNDCCMD 10.53.0.5 stats > /dev/null 2>&1
[ -f ns5/named.stats ] || ret=1
cp ns5/named.stats ns5/named.stats.$n
# Check first 10 lines of Cache DB statistics. After serve-stale queries,
# we expect two active TXT RRsets, one active Others, one nxrrset TXT, and
# one NXDOMAIN.
grep -A 10 "++ Cache DB RRsets ++" ns5/named.stats.$n > ns5/named.stats.$n.cachedb || ret=1
grep "2 TXT" ns5/named.stats.$n.cachedb > /dev/null || ret=1
grep "1 Others" ns5/named.stats.$n.cachedb > /dev/null || ret=1
grep "1 !TXT" ns5/named.stats.$n.cachedb > /dev/null || ret=1
grep "1 NXDOMAIN" ns5/named.stats.$n.cachedb > /dev/null || ret=1
status=$((status+ret))
if [ $ret != 0 ]; then echo_i "failed"; fi
n=$((n+1))
echo_i "disable responses from authoritative server ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.2 txt disable > dig.out.test$n
grep "ANSWER: 1," dig.out.test$n > /dev/null || ret=1
grep "TXT.\"0\"" dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check 'rndc serve-stale status' ($n)"
ret=0
$RNDCCMD 10.53.0.5 serve-stale status > rndc.out.test$n 2>&1 || ret=1
grep "_default: off (not-cached)" rndc.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
sleep 2
echo_i "sending queries for tests $((n+1))-$((n+4))..."
$DIG -p ${PORT} @10.53.0.5 data.example TXT > dig.out.test$((n+1)) &
$DIG -p ${PORT} @10.53.0.5 othertype.example CAA > dig.out.test$((n+2)) &
$DIG -p ${PORT} @10.53.0.5 nodata.example TXT > dig.out.test$((n+3)) &
$DIG -p ${PORT} @10.53.0.5 nxdomain.example TXT > dig.out.test$((n+4))
# ensure all files have been written before proceeding
waitfile dig.out.test$((n+1))
waitfile dig.out.test$((n+2))
waitfile dig.out.test$((n+3))
waitfile dig.out.test$((n+4))
n=$((n+1))
echo_i "check fail of data.example (serve-stale cache disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of othertype.example (serve-stale cache disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of nodata.example (serve-stale cache disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of nxdomain.example (serve-stale cache disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "verify stale cache statistics (serve-stale cache disabled) ($n)"
ret=0
rm -f ns5/named.stats
$RNDCCMD 10.53.0.5 stats > /dev/null 2>&1
[ -f ns5/named.stats ] || ret=1
cp ns5/named.stats ns5/named.stats.$n
# Check first 10 lines of Cache DB statistics. After serve-stale queries,
# we expect one active TXT (longttl) and the rest to be expired from cache.
grep -A 10 "++ Cache DB RRsets ++" ns5/named.stats.$n > ns5/named.stats.$n.cachedb || ret=1
grep -F "1 Others" ns5/named.stats.$n.cachedb > /dev/null || ret=1
grep -F "2 TXT" ns5/named.stats.$n.cachedb > /dev/null || ret=1
grep -F "1 !TXT" ns5/named.stats.$n.cachedb > /dev/null || ret=1
grep -F "1 NXDOMAIN" ns5/named.stats.$n.cachedb > /dev/null || ret=1
status=$((status+ret))
if [ $ret != 0 ]; then echo_i "failed"; fi
# Dump the cache.
n=$((n+1))
echo_i "dump the cache (serve-stale cache disabled) ($n)"
ret=0
$RNDCCMD 10.53.0.5 dumpdb -cache > rndc.out.test$n 2>&1 || ret=1
done=0
for i in 0 1 2 3 4 5 6 7 8 9; do
grep '^; Dump complete$' ns5/named_dump5.db > /dev/null 2>&1 && done=1
if [ $done != 1 ]; then sleep 1; fi
done
if [ $done != 1 ]; then ret=1; fi
status=$((status+ret))
if [ $ret != 0 ]; then echo_i "failed"; fi
echo_i "stop ns5"
$PERL ../stop.pl --use-rndc --port ${CONTROLPORT} serve-stale ns5
# Load the cache as if it was five minutes (RBTDB_VIRTUAL) older.
FIVEMINUTESAGO=`TZ=UTC perl -e 'my $now = time();
my $fiveMinutesAgo = 300;
my ($s, $m, $h, $d, $mo, $y) = (localtime($fiveMinutesAgo))[0, 1, 2, 3, 4, 5];
printf("%04d%02d%02d%02d%02d%02d", $y+1900, $mo+1, $d, $h, $m, $s);'`
n=$((n+1))
echo_i "mock the cache date to $FIVEMINUTESAGO (serve-stale cache disabled) ($n)"
ret=0
sed -E "s/DATE [0-9]{14}/DATE $FIVEMINUTESAGO/g" ns5/named_dump5.db > ns5/named_dumpdb5.db.out || ret=1
cp ns5/named_dumpdb5.db.out ns5/named_dumpdb5.db
if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
echo_i "start ns5"
start_server --noclean --restart --port ${PORT} serve-stale ns5
n=$((n+1))
echo_i "verify ancient cache statistics (serve-stale cache disabled) ($n)"
ret=0
rm -f ns5/named.stats
$RNDCCMD 10.53.0.5 stats #> /dev/null 2>&1
[ -f ns5/named.stats ] || ret=1
cp ns5/named.stats ns5/named.stats.$n
# Check first 10 lines of Cache DB statistics. After last queries, we expect
# everything to be removed or scheduled to be removed.
grep -A 10 "++ Cache DB RRsets ++" ns5/named.stats.$n > ns5/named.stats.$n.cachedb || ret=1
grep -F "#TXT" ns5/named.stats.$n.cachedb > /dev/null && ret=1
grep -F "#Others" ns5/named.stats.$n.cachedb > /dev/null && ret=1
grep -F "#!TXT" ns5/named.stats.$n.cachedb > /dev/null && ret=1
grep -F "#NXDOMAIN" ns5/named.stats.$n.cachedb > /dev/null && ret=1
status=$((status+ret))
if [ $ret != 0 ]; then echo_i "failed"; fi
echo_i "exit status: $status"
[ $status -eq 0 ] || exit 1

22
doc/arm/reference.rst
View file

@ -1815,9 +1815,9 @@ Boolean Options
The default is ``yes``.
``stale-answer-enable``
If ``yes``, enable the returning of "stale" cached answers when the name servers
for a zone are not answering. The default is not to return stale
answers.
If ``yes``, enable the returning of "stale" cached answers when the name
servers for a zone are not answering and the ``stale-cache-enable`` option is
also enabled. The default is not to return stale answers.
Stale answers can also be enabled or disabled at runtime via
``rndc serve-stale on`` or ``rndc serve-stale off``; these override
@ -1831,6 +1831,9 @@ Boolean Options
Information about stale answers is logged under the ``serve-stale``
log category.
``stale-cache-enable``
If ``yes``, enable the retaining of "stale" cached answers. Default ``no``.
``nocookie-udp-size``
This sets the maximum size of UDP responses that are sent to queries
without a valid server COOKIE. A value below 128 is silently
@ -3246,15 +3249,20 @@ Tuning
(such as NS and glue AAAA/A records) in the resolution process.
``max-stale-ttl``
If stale answers are enabled, ``max-stale-ttl`` sets the maximum time
If retaining stale RRsets in cache is enabled, and returning of stale cached
answers is also enabled, ``max-stale-ttl`` sets the maximum time
for which the server retains records past their normal expiry to
return them as stale records, when the servers for those records are
not reachable. The default is 12 hours. The minimum allowed is 1
second; a value of 0 is updated silently to 1 second.
For stale answers to be returned, they must be enabled, either in the
configuration file using ``stale-answer-enable`` or via
``rndc serve-stale on``.
For stale answers to be returned, the retaining of them in cache must be
enabled via the configuration option ``stale-cache-enable``, and returning
cached answers must be enabled, either in the configuration file using the
``stale-answer-enable`` option or by calling ``rndc serve-stale on``.
When ``stale-cache-enable`` is set to ``no``, setting the ``max-stale-ttl``
has no effect, the value of ``max-cache-ttl`` will be ``0`` in such case.
``resolver-nonbackoff-tries``
This specifies how many retries occur before exponential backoff kicks in. The

2
doc/man/named.conf.5in
View file

@ -464,6 +464,7 @@ options {
stacksize ( default | unlimited | sizeval );
stale\-answer\-enable boolean;
stale\-answer\-ttl duration;
stale\-cache\-enable boolean;
startup\-notify\-rate integer;
statistics\-file quoted_string;
synth\-from\-dnssec boolean;
@ -876,6 +877,7 @@ view string [ class ] {
sortlist { address_match_element; ... };
stale\-answer\-enable boolean;
stale\-answer\-ttl duration;
stale\-cache\-enable boolean;
synth\-from\-dnssec boolean;
transfer\-format ( many\-answers | one\-answer );
transfer\-source ( ipv4_address | * ) [ port ( integer | * ) ] [

2
doc/misc/options
View file

@ -365,6 +365,7 @@ options {
stacksize ( default | unlimited | <sizeval> );
stale-answer-enable <boolean>;
stale-answer-ttl <duration>;
stale-cache-enable <boolean>;
startup-notify-rate <integer>;
statistics-file <quoted_string>;
statistics-interval <integer>; // ancient
@ -747,6 +748,7 @@ view <string> [ <class> ] {
sortlist { <address_match_element>; ... };
stale-answer-enable <boolean>;
stale-answer-ttl <duration>;
stale-cache-enable <boolean>;
suppress-initial-notify <boolean>; // not yet implemented
synth-from-dnssec <boolean>;
topology { <address_match_element>; ... }; // ancient

2
doc/misc/options.active
View file

@ -329,6 +329,7 @@ options {
stacksize ( default | unlimited | <sizeval> );
stale-answer-enable <boolean>;
stale-answer-ttl <duration>;
stale-cache-enable <boolean>;
startup-notify-rate <integer>;
statistics-file <quoted_string>;
synth-from-dnssec <boolean>;
@ -676,6 +677,7 @@ view <string> [ <class> ] {
sortlist { <address_match_element>; ... };
stale-answer-enable <boolean>;
stale-answer-ttl <duration>;
stale-cache-enable <boolean>;
synth-from-dnssec <boolean>;
transfer-format ( many-answers | one-answer );
transfer-source ( <ipv4_address> | * ) [ port ( <integer> | * ) ] [

1
doc/misc/options.grammar.rst
View file

@ -258,6 +258,7 @@
stacksize ( default | unlimited | <sizeval> );
stale-answer-enable <boolean>;
stale-answer-ttl <duration>;
stale-cache-enable <boolean>;
startup-notify-rate <integer>;
statistics-file <quoted_string>;
synth-from-dnssec <boolean>;

8
doc/notes/notes-current.rst
View file

@ -36,6 +36,9 @@ New Features
- Statistics channels have also been updated to use the new BIND network
manager API. [GL #2022]
- A new configuration option ``stale-cache-enable`` has been introduced to
enable or disable the keeping of stale answers in cache. [GL #1712]
Feature Changes
~~~~~~~~~~~~~~~
@ -46,6 +49,11 @@ Feature Changes
prevents interruption to query resolution when the hash tables need to be
increased in size. [GL #1775]
- Keeping stale answers in cache has been disabled by default.
- The resource records received with 0 TTL are no longer kept in the cache
to be used for stale answers. [GL #1829]
Bug Fixes
~~~~~~~~~

8
lib/dns/rbtdb.c
View file

@ -1630,6 +1630,8 @@ mark_header_stale(dns_rbtdb_t *rbtdb, rdatasetheader_t *header) {
uint_least16_t attributes = atomic_load_acquire(&header->attributes);
uint_least16_t newattributes = 0;
INSIST((attributes & RDATASET_ATTR_ZEROTTL) == 0);
/*
* If we are already stale there is nothing to do.
*/
@ -4522,9 +4524,11 @@ check_stale_header(dns_rbtnode_t *node, rdatasetheader_t *header,
/*
* If this data is in the stale window keep it and if
* DNS_DBFIND_STALEOK is not set we tell the caller to
* skip this record.
* skip this record. We skip the records with ZEROTTL
* (these records should not be cached anyway).
*/
if (KEEPSTALE(search->rbtdb) && stale > search->now) {
if (!ZEROTTL(header) && KEEPSTALE(search->rbtdb) &&
stale > search->now) {
mark_header_stale(search->rbtdb, header);
*header_prev = header;
return ((search->options & DNS_DBFIND_STALEOK) == 0);

1
lib/isccfg/namedconf.c
View file

@ -2045,6 +2045,7 @@ static cfg_clausedef_t view_clauses[] = {
{ "sortlist", &cfg_type_bracketed_aml, 0 },
{ "stale-answer-enable", &cfg_type_boolean, 0 },
{ "stale-answer-ttl", &cfg_type_duration, 0 },
{ "stale-cache-enable", &cfg_type_boolean, 0 },
{ "suppress-initial-notify", &cfg_type_boolean, CFG_CLAUSEFLAG_NYI },
{ "synth-from-dnssec", &cfg_type_boolean, 0 },
{ "topology", &cfg_type_bracketed_aml, CFG_CLAUSEFLAG_ANCIENT },