The test works as follows:
1. Client wants to resolve unusual ip6.arpa. name:
test1.test2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.9.0.9.4.1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa. IN TXT
2. Query is sent to ns7, a qmin enabled resolver.
3. ns7 do the first stage in query minimization for the name and send a new
query to root (ns1):
_.1.0.0.2.ip6.arpa. IN A
4. ns1 delegates ip6.arpa. to ns2.good.:
;; AUTHORITY SECTION:
;ip6.arpa. 20 IN NS ns2.good.
;; ADDITIONAL SECTION:
;ns2.good. 20 IN A 10.53.0.2
5. ns7 do a second round in minimizing the name and send a new query
to ns2.good. (10.53.0.2):
_.8.2.6.0.1.0.0.2.ip6.arpa. IN A
6. ans2 delegates 8.2.6.0.1.0.0.2.ip6.arpa. to ns3.good.:
;; AUTHORITY SECTION:
;8.2.6.0.1.0.0.2.ip6.arpa. 60 IN NS ns3.good.
;; ADDITIONAL SECTION:
;ns3.good. 60 IN A 10.53.0.3
7. ns7 do a third round in minimizing the name and send a new query to
ns3.good.:
_.1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa. IN A
8. ans3 delegates 1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa. to ns4.good.:
;; AUTHORITY SECTION:
;1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa. 60 IN NS ns4.good.
;; ADDITIONAL SECTION:
;ns4.good. 60 IN A 10.53.0.4
9. ns7 do fourth round in minimizing the name and send a new query to
ns4.good.:
_.9.4.1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa. IN A
10. ns4.good. doesn't know such name, but answers stating it is authoritative for
the domai:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 53815
...
;; AUTHORITY SECTION:
1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa. 60 IN SOA ns4.good. ...
11. ns7 do another minimization on name:
_.9.0.9.4.1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa
sends to ns4.good. and gets the same SOA response stated in item #10
12. ns7 do another minimization on name:
_.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.9.0.9.4.1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa
sends to ns4.good. and gets the same SOA response stated in item #10.
13. ns7 do the last query minimization name for the ip6.arpa. QNAME.
After all IPv6 labels are exausted the algorithm falls back to the
original QNAME:
test1.test2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.9.0.9.4.1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa
ns7 sends a new query with the original QNAME to ans4.
14. Finally ans4 answers with the expected response:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40969
;; flags: qr aa; QUESTION: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 8192
;; QUESTION SECTION:
;test1.test2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.9.0.9.4.1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa. IN TXT
;; ANSWER SECTION:
;test1.test2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.9.0.9.4.1.1.1.1.8.2.6.0.1.0.0.2.ip6.arpa. 1 IN TXT "long_ip6_name"
The test for assertion failure via large TCP packet needs to be repeated
multiple times (we use 300000). This commit fixes the input file to be
properly hexlified and uses the new packet.pl -r feature to send it
300000 times via TCP.
For some tests, we need to send big data streams (for TCP) or repeated
packets (for UDP), this commits adds `-r` option to packet.pl that sends
the same input <repeats> times using the specified protocol.
In order to lower the amount of memory allocated at startup by named
instances used in the BIND system test suite, set the default value of
"max-cache-size" for these to 2 megabytes. The purpose of this change
is to prevent named instances (or even entire virtual machines) from
getting killed by the operating system on the test host due to excessive
memory use.
Remove all "max-cache-size" statements from named configuration files
used in system tests ("checkconf" notwithstanding) to prevent confusion
as the "-T maxcachesize=..." command line option takes precedence over
configuration files.
Prevent intermittent false positives on slow platforms by subtracting
the number of seconds which passed between key creation and invoking
'rndc dnssec -checkds'.
This particularly fails for the step3.csk-roll2.autosign zone because
the closest next key event is when the zone signatures become
omnipresent. Running 'rndc dnssec -checkds' some time later means
that the next key event is in fact closer than the calculated time
and thus we need to adjust the expected time by the time already
passed.
Previously .txt files with full backtrace may be identified as a
crashed test:
I:Core dumps were found for the following system tests:
I: core.19948-backtrace.txt
I: shutdown
Now .txt files are removed from the list.
Change 'run.sh.in' to match the core matching pattern in
'testsummary.sh'.
Make sure the 'checkds' command correctly sets the right key timing
metadata and also make sure that it rejects setting the key timing
metadata if there are multiple keys with the KSK role and no key
identifier is provided.
With 'checkds' replacing 'parent-registration-delay', the kasp
test needs the expected times to be adjusted. Also the system test
needs to call 'rndc dnssec -checkds' to progress the rollovers.
Since we pretend that the KSK is active as soon as the DS is
submitted (and parent registration delay is no longer applicable)
we can simplify the 'csk_rollover_predecessor_keytimes' function
to take only one "addtime" parameter.
This commit also slightly changes the 'check_dnssecstatus' function,
passing the zone as a parameter.
The named configuration files used in the "geoip2" system test cause a
rather large number of views (6-8) to be set up in each tested named
instance. Each view has its own cache.
Commit e24bc324b4 caused the RBT hash
table to be pre-allocated to a size derived from "max-cache-size", so
that it never needs to be rehashed. The size of that hash table is not
expected to be significant enough to cause memory use issues in typical
conditions even for large "max-cache-size" settings.
However, these two factors combined can cause memory exhaustion issues
in GitLab CI, where we run multiple "instances" of the test suite in
parallel on the same runner, each test suite executes multiple system
tests concurrently, and each system test may potentially start multiple
named instances at the same time. In practice, this problem currently
only seems to be affecting the "geoip2" system test, which is failing
intermittently due to named instances used by that test getting killed
by oom-killer.
Prevent the "geoip2" system test from failing intermittently by setting
"max-cache-size" in named configuration files used in that test to a low
value in order to keep memory usage at bay even with a large number of
views configured.
The current serve-stale implementation in BIND 9 stores all received
records in the cache for a max-stale-ttl interval (default 12 hours).
This allows DNS operators to turn the serve-stale answers in an event of
large authoritative DNS outage. The caching of the stale answers needs
to be enabled before the outage happens or the feature would be
otherwise useless.
The negative consequence of the default setting is the inevitable
cache-bloat that happens for every and each DNS operator running named.
In this MR, a new configuration option `stale-cache-enable` is
introduced that allows the operators to selectively enable or disable
the serve-stale feature of BIND 9 based on their decision.
The newly introduced option has been disabled by default,
e.g. serve-stale is disabled in the default configuration and has to be
enabled if required.
It seems that config.guess gets always created in source root, so for
that sake of out-of-tree system test, we should expect the file there
instead of where configure was run.
The $SYSTEMTESTTOP shell variable if often set to .. in various shell
scripts inside bin/tests/system/, but most of the time it is only
used one line later, while sourcing conf.sh. This hardly improves
code readability.
$SYSTEMTESTTOP is also used for the purpose of referencing
scripts/files living in bin/tests/system/, but given that the
variable is always set to a short, relative path, we can drop it and
replace all of its occurrences with the relative path without adversely
affecting code readability.
There were several problems with rbt hashtable implementation:
1. Our internal hashing function returns uint64_t value, but it was
silently truncated to unsigned int in dns_name_hash() and
dns_name_fullhash() functions. As the SipHash 2-4 higher bits are
more random, we need to use the upper half of the return value.
2. The hashtable implementation in rbt.c was using modulo to pick the
slot number for the hash table. This has several problems because
modulo is: a) slow, b) oblivious to patterns in the input data. This
could lead to very uneven distribution of the hashed data in the
hashtable. Combined with the single-linked lists we use, it could
really hog-down the lookup and removal of the nodes from the rbt
tree[a]. The Fibonacci Hashing is much better fit for the hashtable
function here. For longer description, read "Fibonacci Hashing: The
Optimization that the World Forgot"[b] or just look at the Linux
kernel. Also this will make Diego very happy :).
3. The hashtable would rehash every time the number of nodes in the rbt
tree would exceed 3 * (hashtable size). The overcommit will make the
uneven distribution in the hashtable even worse, but the main problem
lies in the rehashing - every time the database grows beyond the
limit, each subsequent rehashing will be much slower. The mitigation
here is letting the rbt know how big the cache can grown and
pre-allocate the hashtable to be big enough to actually never need to
rehash. This will consume more memory at the start, but since the
size of the hashtable is capped to `1 << 32` (e.g. 4 mio entries), it
will only consume maximum of 32GB of memory for hashtable in the
worst case (and max-cache-size would need to be set to more than
4TB). Calling the dns_db_adjusthashsize() will also cap the maximum
size of the hashtable to the pre-computed number of bits, so it won't
try to consume more gigabytes of memory than available for the
database.
FIXME: What is the average size of the rbt node that gets hashed? I
chose the pagesize (4k) as initial value to precompute the size of
the hashtable, but the value is based on feeling and not any real
data.
For future work, there are more places where we use result of the hash
value modulo some small number and that would benefit from Fibonacci
Hashing to get better distribution.
Notes:
a. A doubly linked list should be used here to speedup the removal of
the entries from the hashtable.
b. https://probablydance.com/2018/06/16/fibonacci-hashing-the-optimization-that-the-world-forgot-or-a-better-alternative-to-integer-modulo/
Make sure bin/tests/system/run.sh returns a non-zero exit code if any of
the following happens:
- the test being run produces a core dump,
- assertion failures are found in the test's logs,
- ThreadSanitizer reports are found after the test completes,
- the servers started by the test fail to shut down cleanly.
This change is necessary to always fail a test in such cases (before the
migration to Automake, test failures were determined based on the
presence of "R:<test-name>:FAIL" lines in the test suite output and thus
it was not necessary for bin/tests/system/run.sh to return a non-zero
exit code).
While the creation and publication times of the various keys
in this policy are nearly at the same time there is a chance that
one key is created a second later than the other.
The `set_keytimes_algorithm_policy` mistakenly set the keytimes
for KEY3 based of the "published" time from KEY2.
this changes most visble uses of master/slave terminology in tests.sh
and most uses of 'type master' or 'type slave' in named.conf files.
files in the checkconf test were not updated in order to confirm that
the old syntax still works. rpzrecurse was also left mostly unchanged
to avoid interference with DNSRPS.
it is now an error to have two primaries lists with the same
name. this is true regardless of whether the "primaries" or
"masters" keywords were used to define them.
as "type primary" is preferred over "type master" now, it makes
sense to make "primaries" available as a synonym too.
added a correctness check to ensure "primaries" and "masters"
cannot both be used in the same zone.
This test ensures that named will correctly shutdown
when receiving multiple control connections after processing
of either "rncd stop" or "kill -SIGTERM" commands.
Before the fix, named was crashing due to a race condition happening
between two threads, one running shutdown logic in named/server.c
and other handling control logic in controlconf.c.
This test tries to reproduce the above scenario by issuing multiple
queries to a target named instance, issuing either rndc stop or kill
-SIGTERM command to the same named instance, then starting multiple rndc
status connections to ensure it is not crashing anymore.
Matthijs Mekking
Mark Andrews
Diego Fronza
Ondřej Surý
Michał Kępień
Evan HuntandOndřej Surý
Ondřej SurýandOndřej Surý
Michal Nowak