Send the ns_query_cancel() on the recursing clients when we initiate the
named shutdown for faster shutdown.
When we are shutting down the resolver, we cancel all the outstanding
fetches, and the ISC_R_CANCEL events doesn't propagate to the ns_client
callback.
In the future, the better solution how to fix this would be to look at
the shutdown paths and let them all propagate from bottom (loopmgr) to
top (f.e. ns_client).
(cherry picked from commit d861d403bb9a7912e29a06aba6caf6d502839f1b)
The incrementing and decrementing of 'ns_statscounter_recursclients'
were not properly balanced: for example, it would be incremented for
a prefetch query but not decremented if the query failed.
This commit ensures that the recursion quota and the recursive clients
counter are always in sync with each other.
(cherry picked from commit 82991451b4)
It is possible to bypass Response Rate Limiting (RRL)
`responses-per-second` limitation using specially crafted wildcard
names, because the current implementation, when encountering a found
DNS name generated from a wildcard record, just strips the leftmost
label of the name before making a key for the bucket.
While that technique helps with limiting random requests like
<random>.example.com (because all those requests will be accounted
as belonging to a bucket constructed from "example.com" name), it does
not help with random names like subdomain.<random>.example.com.
The best solution would have been to strip not just the leftmost
label, but as many labels as necessary until reaching the suffix part
of the wildcard record from which the found name is generated, however,
we do not have that information readily available in the context of RRL
processing code.
Fix the issue by interpreting all valid wildcard domain names as
the zone's origin name concatenated to the "*" name, so they all will
be put into the same bucket.
(cherry picked from commit baa9698c9d)
The BUFSIZ value varies between platforms, it could be 8K on Linux and
512 bytes on mingw. Make sure the buffers are always big enough for the
output data to prevent truncation of the output by appropriately
enlarging or sizing the buffers.
(cherry picked from commit b19d932262)
The current logic for determining the address of the socket to which a
client sent its query is:
1. Get the address:port tuple from the netmgr handle using
isc_nmhandle_localaddr() or from the ns_interface_t structure.
2. Convert the address:port tuple from step 1 into an isc_netaddr_t
using isc_netaddr_fromsockaddr().
3. Convert the address from step 2 back into a socket address with the
port set to 0 using isc_sockaddr_fromnetaddr().
Note that the port number (readily available in the netmgr handle or in
the ns_interface_t structure) is needlessly lost in the process,
preventing it from being recorded in dnstap captures of client traffic
produced by named.
Fix by first storing the address:port tuple in client->destsockaddr and
then creating an isc_netaddr_t from that structure. This allows the
port number to be retained in client->destsockaddr, which is what
subsequently gets passed to dns_dt_send().
Remove an outdated code comment.
(cherry picked from commit 2f945703f2)
Historically, the inline keyword was a strong suggestion to the compiler
that it should inline the function marked inline. As compilers became
better at optimising, this functionality has receded, and using inline
as a suggestion to inline a function is obsolete. The compiler will
happily ignore it and inline something else entirely if it finds that's
a better optimisation.
Therefore, remove all the occurences of the inline keyword with static
functions inside single compilation unit and leave the decision whether
to inline a function or not entirely on the compiler
NOTE: We keep the usage the inline keyword when the purpose is to change
the linkage behaviour.
(cherry picked from commit 20f0936cf2)
Previously, the unreachable code paths would have to be tagged with:
INSIST(0);
ISC_UNREACHABLE();
There was also older parts of the code that used comment annotation:
/* NOTREACHED */
Unify the handling of unreachable code paths to just use:
UNREACHABLE();
The UNREACHABLE() macro now asserts when reached and also uses
__builtin_unreachable(); when such builtin is available in the compiler.
(cherry picked from commit 584f0d7a7e)
The C17 standard deprecated ATOMIC_VAR_INIT() macro (see [1]). Follow
the suite and remove the ATOMIC_VAR_INIT() usage in favor of simple
assignment of the value as this is what all supported stdatomic.h
implementations do anyway:
* MacOSX.plaform: #define ATOMIC_VAR_INIT(__v) {__v}
* Gcc stdatomic.h: #define ATOMIC_VAR_INIT(VALUE) (VALUE)
1. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1138r0.pdf
(cherry picked from commit f251d69eba)
This commit converts the license handling to adhere to the REUSE
specification. It specifically:
1. Adds used licnses to LICENSES/ directory
2. Add "isc" template for adding the copyright boilerplate
3. Changes all source files to include copyright and SPDX license
header, this includes all the C sources, documentation, zone files,
configuration files. There are notes in the doc/dev/copyrights file
on how to add correct headers to the new files.
4. Handle the rest that can't be modified via .reuse/dep5 file. The
binary (or otherwise unmodifiable) files could have license places
next to them in <foo>.license file, but this would lead to cluttered
repository and most of the files handled in the .reuse/dep5 file are
system test files.
(cherry picked from commit 58bd26b6cf)
previously, receiving a keepalive option had no effect on how
long named would keep the connection open; there was a place to
configure the keepalive timeout but it was never used. this commit
corrects that.
this also fixes an error in isc__nm_tcpdns_keepalive()
in which the sense of a REQUIRE test was reversed; previously this
error had not been noticed because the functions were not being
used.
(cherry picked from commit 7867b8b57d)
The client->rcode_override was originally created to force the server
to send SERVFAIL in some cases when it would normally have sent FORMERR.
More recently, it was used in a3ba95116e
commit (part of GL #2790) to force the sending of a TC=1 NOERROR
response, triggering a retry via TCP, when a UDP packet could not be
sent due to ISC_R_MAXSIZE.
This ran afoul of a pre-existing INSIST in ns_client_error() when
RRL was in use. the INSIST was based on the assumption that
ns_client_error() could never result in a non-error rcode. as
that assumption is no longer valid, the INSIST has been removed.
When the fragmentation is disabled on UDP sockets, the uv_udp_send()
call can fail with UV_EMSGSIZE for messages larger than path MTU.
Previously, this error would end with just discarding the response. In
this commit, a proper handling of such case is added and on such error,
a new DNS response with truncated bit set is generated and sent to the
client.
This change allows us to disable the fragmentation on the UDP
sockets again.
(cherry picked from commit a3ba95116e)
configuring with --enable-mutex-atomics flagged these incorrectly
initialised variables on systems where pthread_mutex_init doesn't
just zero out the structure.
(cherry picked from commit 715a2c7fc1)
dns_message_gettempname() now returns a pointer to an initialized
name associated with a dns_fixedname_t object. it is no longer
necessary to allocate a buffer for temporary names associated with
the message object.
(cherry picked from commit e31cc1eeb4)
this rolls up numerous changes that have been applied to the
main branch, including moving isc_task operations into the
netmgr event loops, and other general stabilization.
The RFC7828 specifies the keepalive interval to be 16-bit, specified in
units of 100 milliseconds and the configuration options tcp-*-timeouts
are following the suit. The units of 100 milliseconds are very
unintuitive and while we can't change the configuration and presentation
format, we should not follow this weird unit in the API.
This commit changes the isc_nm_(get|set)timeouts() functions to work
with milliseconds and convert the values to milliseconds before passing
them to the function, not just internally.
This commit allows stale RRset to be used (if available) for responding
a query, before an attempt to refresh an expired, or otherwise resolve
an unavailable RRset in cache is made.
For that to work, a value of zero must be specified for
stale-answer-client-timeout statement.
To better understand the logic implemented, there are three flags being
used during database lookup and other parts of code that must be
understood:
. DNS_DBFIND_STALEOK: This flag is set when BIND fails to refresh a
RRset due to timeout (resolver-query-timeout), its intent is to
try to look for stale data in cache as a fallback, but only if
stale answers are enabled in configuration.
This flag is also used to activate stale-refresh-time window, since it
is the only way the database knows that a resolution has failed.
. DNS_DBFIND_STALEENABLED: This flag is used as a hint to the database
that it may use stale data. It is always set during query lookup if
stale answers are enabled, but only effectively used during
stale-refresh-time window. Also during this window, the resolver will
not try to resolve the query, in other words no attempt to refresh the
data in cache is made when the stale-refresh-time window is active.
. DNS_DBFIND_STALEONLY: This new introduced flag is used when we want
stale data from the database, but not due to a failure in resolution,
it also doesn't require stale-refresh-time window timer to be active.
As long as there is a stale RRset available, it should be returned.
It is mainly used in two situations:
1. When stale-answer-client-timeout timer is triggered: in that case
we want to know if there is stale data available to answer the
client.
2. When stale-answer-client-timeout value is set to zero: in that
case, we also want to know if there is some stale RRset available
to promptly answer the client.
We must also discern between three situations that may happen when
resolving a query after the addition of stale-answer-client-timeout
statement, and how to handle them:
1. Are we running query_lookup() due to stale-answer-client-timeout
timer being triggered?
In this case, we look for stale data, making use of
DNS_DBFIND_STALEONLY flag. If a stale RRset is available then
respond the client with the data found, mark this query as
answered (query attribute NS_QUERYATTR_ANSWERED), so when the
fetch completes the client won't be answered twice.
We must also take care of not detaching from the client, as a
fetch will still be running in background, this is handled by the
following snippet:
if (!QUERY_STALEONLY(&client->query)) {
isc_nmhandle_detach(&client->reqhandle);
}
Which basically tests if DNS_DBFIND_STALEONLY flag is set, which
means we are here due to a stale-answer-client-timeout timer
expiration.
2. Are we running query_lookup() due to resolver-query-timeout being
triggered?
In this case, DNS_DBFIND_STALEOK flag will be set and an attempt
to look for stale data will be made.
As already explained, this flag is algo used to activate
stale-refresh-time window, as it means that we failed to refresh
a RRset due to timeout.
It is ok in this situation to detach from the client, as the
fetch is already completed.
3. Are we running query_lookup() during the first time, looking for
a RRset in cache and stale-answer-client-timeout value is set to
zero?
In this case, if stale answers are enabled (probably), we must do
an initial database lookup with DNS_DBFIND_STALEONLY flag set, to
indicate to the database that we want stale data.
If we find an active RRset, proceed as normal, answer the client
and the query is done.
If we find a stale RRset we respond to the client and mark the
query as answered, but don't detach from the client yet as an
attempt in refreshing the RRset will still be made by means of
the new introduced function 'query_resolve'.
If no active or stale RRset is available, begin resolution as
usual.
(cherry picked from commit e219422575)
The general logic behind the addition of this new feature works as
folows:
When a client query arrives, the basic path (query.c / ns_query_recurse)
was to create a fetch, waiting for completion in fetch_callback.
With the introduction of stale-answer-client-timeout, a new event of
type DNS_EVENT_TRYSTALE may invoke fetch_callback, whenever stale
answers are enabled and the fetch took longer than
stale-answer-client-timeout to complete.
When an event of type DNS_EVENT_TRYSTALE triggers fetch_callback, we
must ensure that the folowing happens:
1. Setup a new query context with the sole purpose of looking up for
stale RRset only data, for that matters a new flag was added
'DNS_DBFIND_STALEONLY' used in database lookups.
. If a stale RRset is found, mark the original client query as
answered (with a new query attribute named NS_QUERYATTR_ANSWERED),
so when the fetch completion event is received later, we avoid
answering the client twice.
. If a stale RRset is not found, cleanup and wait for the normal
fetch completion event.
2. In ns_query_done, we must change this part:
/*
* If we're recursing then just return; the query will
* resume when recursion ends.
*/
if (RECURSING(qctx->client)) {
return (qctx->result);
}
To this:
if (RECURSING(qctx->client) && !QUERY_STALEONLY(qctx->client)) {
return (qctx->result);
}
Otherwise we would not proceed to answer the client if it happened
that a stale answer was found when looking up for stale only data.
When an event of type DNS_EVENT_FETCHDONE triggers fetch_callback, we
proceed as before, resuming query, updating stats, etc, but a few
exceptions had to be added, most important of which are two:
1. Before answering the client (ns_client_send), check if the query
wasn't already answered before.
2. Before detaching a client, e.g.
isc_nmhandle_detach(&client->reqhandle), ensure that this is the
fetch completion event, and not the one triggered due to
stale-answer-client-timeout, so a correct call would be:
if (!QUERY_STALEONLY(client)) {
isc_nmhandle_detach(&client->reqhandle);
}
Other than these notes, comments were added in code in attempt to make
these updates easier to follow.
(cherry picked from commit 171a5b7542)
This is a part of the works that intends to make the netmgr stable,
testable, maintainable and tested. It contains a numerous changes to
the netmgr code and unfortunately, it was not possible to split this
into smaller chunks as the work here needs to be committed as a complete
works.
NOTE: There's a quite a lot of duplicated code between udp.c, tcp.c and
tcpdns.c and it should be a subject to refactoring in the future.
The changes that are included in this commit are listed here
(extensively, but not exclusively):
* The netmgr_test unit test was split into individual tests (udp_test,
tcp_test, tcpdns_test and newly added tcp_quota_test)
* The udp_test and tcp_test has been extended to allow programatic
failures from the libuv API. Unfortunately, we can't use cmocka
mock() and will_return(), so we emulate the behaviour with #define and
including the netmgr/{udp,tcp}.c source file directly.
* The netievents that we put on the nm queue have variable number of
members, out of these the isc_nmsocket_t and isc_nmhandle_t always
needs to be attached before enqueueing the netievent_<foo> and
detached after we have called the isc_nm_async_<foo> to ensure that
the socket (handle) doesn't disappear between scheduling the event and
actually executing the event.
* Cancelling the in-flight TCP connection using libuv requires to call
uv_close() on the original uv_tcp_t handle which just breaks too many
assumptions we have in the netmgr code. Instead of using uv_timer for
TCP connection timeouts, we use platform specific socket option.
* Fix the synchronization between {nm,async}_{listentcp,tcpconnect}
When isc_nm_listentcp() or isc_nm_tcpconnect() is called it was
waiting for socket to either end up with error (that path was fine) or
to be listening or connected using condition variable and mutex.
Several things could happen:
0. everything is ok
1. the waiting thread would miss the SIGNAL() - because the enqueued
event would be processed faster than we could start WAIT()ing.
In case the operation would end up with error, it would be ok, as
the error variable would be unchanged.
2. the waiting thread miss the sock->{connected,listening} = `true`
would be set to `false` in the tcp_{listen,connect}close_cb() as
the connection would be so short lived that the socket would be
closed before we could even start WAIT()ing
* The tcpdns has been converted to using libuv directly. Previously,
the tcpdns protocol used tcp protocol from netmgr, this proved to be
very complicated to understand, fix and make changes to. The new
tcpdns protocol is modeled in a similar way how tcp netmgr protocol.
Closes: #2194, #2283, #2318, #2266, #2034, #1920
* The tcp and tcpdns is now not using isc_uv_import/isc_uv_export to
pass accepted TCP sockets between netthreads, but instead (similar to
UDP) uses per netthread uv_loop listener. This greatly reduces the
complexity as the socket is always run in the associated nm and uv
loops, and we are also not touching the libuv internals.
There's an unfortunate side effect though, the new code requires
support for load-balanced sockets from the operating system for both
UDP and TCP (see #2137). If the operating system doesn't support the
load balanced sockets (either SO_REUSEPORT on Linux or SO_REUSEPORT_LB
on FreeBSD 12+), the number of netthreads is limited to 1.
* The netmgr has now two debugging #ifdefs:
1. Already existing NETMGR_TRACE prints any dangling nmsockets and
nmhandles before triggering assertion failure. This options would
reduce performance when enabled, but in theory, it could be enabled
on low-performance systems.
2. New NETMGR_TRACE_VERBOSE option has been added that enables
extensive netmgr logging that allows the software engineer to
precisely track any attach/detach operations on the nmsockets and
nmhandles. This is not suitable for any kind of production
machine, only for debugging.
* The tlsdns netmgr protocol has been split from the tcpdns and it still
uses the old method of stacking the netmgr boxes on top of each other.
We will have to refactor the tlsdns netmgr protocol to use the same
approach - build the stack using only libuv and openssl.
* Limit but not assert the tcp buffer size in tcp_alloc_cb
Closes: #2061
(cherry picked from commit 634bdfb16d)
ns_client_sendraw() is currently only used to relay UPDATE
responses back to the client. dns_dt_send() is called with
this assumption.
(cherry picked from commit b09727a765)
1. The isc__nm_tcp_send() and isc__nm_tcp_read() was not checking
whether the socket was still alive and scheduling reads/sends on
closed socket.
2. The isc_nm_read(), isc_nm_send() and isc_nm_resumeread() have been
changed to always return the error conditions via the callbacks, so
they always succeed. This applies to all protocols (UDP, TCP and
TCPDNS).
(cherry picked from commit f7c82e406e)
Attaching and detaching handle pointers will make it easier to
determine where and why reference counting errors have occurred.
A handle needs to be referenced more than once when multiple
asynchronous operations are in flight, so callers must now maintain
multiple handle pointers for each pending operation. For example,
ns_client objects now contain:
- reqhandle: held while waiting for a request callback (query,
notify, update)
- sendhandle: held while waiting for a send callback
- fetchhandle: held while waiting for a recursive fetch to
complete
- updatehandle: held while waiting for an update-forwarding
task to complete
(cherry picked from commit 57b4dde974)
the blackhole ACL was accidentally disabled with respect to client
queries during the netmgr conversion.
in order to make this work for TCP, it was necessary to add a return
code to the accept callback functions passed to isc_nm_listentcp() and
isc_nm_listentcpdns().
(cherry picked from commit 23c7373d68)
this will allow recv event handlers to distinguish between cases
in which the region is NULL because of error, shutdown, or cancelation.
(cherry picked from commit 75c985c07f)
The following reverted changes will be picked again as part of the
netmgr sync with main branch.
Revert "Merge branch '1996-confidential-issue-v9_16' into 'security-v9_16'"
This reverts commit e160b1509f, reversing
changes made to c01e643715.
Revert "Merge branch '2038-use-freebind-when-bind-fails-v9_16' into 'v9_16'"
This reverts commit 5f8ecfb918, reversing
changes made to 23021385d5.
Revert "Merge branch '1936-blackhole-fix-v9_16' into 'v9_16'"
This reverts commit f20bc90a72, reversing
changes made to 490016ebf1.
Revert "Merge branch '1938-fix-udp-race' into 'v9_16'"
This reverts commit 0a6c7ab2a9, reversing
changes made to 4ea84740e6.
Revert "Merge branch '1947-fix-tcpdns-race' into 'v9_16'"
This reverts commit 4ea84740e6, reversing
changes made to d761cd576b.
The dns_message_create() function cannot soft fail (as all memory
allocations either succeed or cause abort), so we change the function to
return void and cleanup the calls.
(cherry picked from commit 33eefe9f85)
This commit will be used as a base for the next code updates in
order to have a better control of dns_message_t objects' lifetime.
(cherry picked from commit 12d6d13100)
Now that the log message has been printed set the result code to
DNS_R_FORMERR. We don't do this via dns_result_torcode() as we
don't want upstream errors to produce FORMERR if that processing
end with DNS_R_BADTSIG.
(cherry picked from commit 20488d6ad3)
the blackhole ACL was accidentally disabled with respect to client
queries during the netmgr conversion.
in order to make this work for TCP, it was necessary to add a return
code to the accept callback functions passed to isc_nm_listentcp() and
isc_nm_listentcpdns().
(cherry picked from commit 23c7373d68)
NS_CLIENT_TCP_BUFFER_SIZE was 2 byte too large following the
move to netmgr add associated changes to lib/ns/client.c and
as a result an INSIST could be trigger if the DNS message being
constructed had a checkpoint stage that fell in those two extra
bytes. Adjusted NS_CLIENT_TCP_BUFFER_SIZE and cleaned up
client_allocsendbuf now that the previously reserved 2 bytes
are no longer used.
(cherry picked from commit 5a92af19b7dce684b0e6670ae6ec1c4c58613263)
In case of normal fetch, the .recursionquota is attached and
ns_statscounter_recursclients is incremented when the fetch is created. Then
the .recursionquota is detached and the counter decremented in the
fetch_callback().
In case of prefetch or rpzfetch, the quota is attached, but the counter is not
incremented. When we reach the soft-quota, the function returns early but don't
detach from the quota, and it gets destroyed during the ns_client_endrequest(),
so no memory was leaked.
But because the ns_statscounter_recursclients is only incremented during the
normal fetch the counter would be incorrectly decremented on two occassions:
1) When we reached the softquota, because the quota was not properly detached
2) When the prefetch or rpzfetch was cancelled mid-flight and the callback
function was never called.
(cherry picked from commit 78886d4bed)
Fixes a race between ns_client_killoldestquery and ns_client_endrequest -
killoldestquery takes a client from `recursing` list while endrequest
destroys client object, then killoldestquery works on a destroyed client
object. Prevent it by holding reclist lock while cancelling query.
(cherry picked from commit df3dbdff81)
Fix a potential assertion failure on shutdown in ns__client_endrequest.
Scenario:
1. We are shutting down, interface->clientmgr is gone.
2. We receive a packet, it gets through ns__client_request
3. mgr == NULL, return
4. isc_nmhandle_detach calls ns_client_reset_cb
5. ns_client_reset_cb calls ns_client_endrequest
6. INSIST(client->state == NS_CLIENTSTATE_WORKING ||
client->state == NS_CLIENTSTATE_RECURSING) is not met
- we haven't started processing this packet so
client->state == NS_CLIENTSTATE_READY.
As a solution - don't do anything in ns_client_reset_cb if the client
is still in READY state.
(cherry picked from commit b0888ff039)
Start enforcing the clang-format rules on changed files
Closes#46
See merge request isc-projects/bind9!3063
(cherry picked from commit a04cdde45d)
d2b5853b Start enforcing the clang-format rules on changed files
618947c6 Switch AlwaysBreakAfterReturnType from TopLevelDefinitions to All
654927c8 Add separate .clang-format files for headers
5777c44a Reformat using the new rules
60d29f69 Don't enforce copyrights on .clang-format
adjust clang-format options to get closer to ISC style
See merge request isc-projects/bind9!3061
(cherry picked from commit d3b49b6675)
0255a974 revise .clang-format and add a C formatting script in util
e851ed0b apply the modified style
Add curly braces using uncrustify and then reformat with clang-format back
Closes#46
See merge request isc-projects/bind9!3057
(cherry picked from commit 67b68e06ad)
36c6105e Use coccinelle to add braces to nested single line statement
d14bb713 Add copy of run-clang-tidy that can fixup the filepaths
056e133c Use clang-tidy to add curly braces around one-line statements
Reformat source code with clang-format
Closes#46
See merge request isc-projects/bind9!2156
(cherry picked from commit 7099e79a9b)
4c3b063e Import Linux kernel .clang-format with small modifications
f50b1e06 Use clang-format to reformat the source files
11341c76 Update the definition files for Windows
df6c1f76 Remove tkey_test (which is no-op anyway)
Also disable the semantic patch as the code needs tweaks here and there because
some destroy functions might not destroy the object and return early if the
object is still in use.
The isc_buffer_allocate() function now cannot fail with ISC_R_MEMORY.
This commit removes all the checks on the return code using the semantic
patch from previous commit, as isc_buffer_allocate() now returns void.
We weren't consistent about who should unreference the handle in
case of network error. Make it consistent so that it's always the
client code responsibility to unreference the handle - either
in the callback or right away if send function failed and the callback
will never be called.
Ondřej Surý
Aram Sargsyan
Ondřej SurýandOndřej Surý
Evan Hunt
Mark AndrewsandOndřej Surý
Witold KręcickiandDiego Fronza
