As the query_prefetch() or query_rpzfetch() could be called during
"regular" fetch, we need to introduce separate storage for attaching
the nmhandle during prefetching the records. The query_prefetch()
and query_rpzfetch() are guarded for re-entrance by .query.prefetch
member of ns_client_t, so we can reuse the same .prefetchhandle for
both.
(cherry picked from commit d4976e0ebe)
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 basic scenario for the problem was that in the process of
resolving a query, if any rrset was eligible for prefetching, then it
would trigger a call to query_prefetch(), this call would run in
parallel to the normal query processing.
The problem arises due to the fact that both query_prefetch(), and,
in the original thread, a call to ns_query_recurse(), try to attach
to the recursionquota, but recursing client stats counter is only
incremented if ns_query_recurse() attachs to it first.
Conversely, if fetch_callback() is called before prefetch_done(),
it would not only detach from recursionquota, but also decrement
the stats counter, if query_prefetch() attached to te quota first
that would result in a decrement not matched by an increment, as
expected.
To solve this issue an atomic bool was added, it is set once in
ns_query_recurse(), allowing fetch_callback() to check for it
and decrement stats accordingly.
For a more compreensive explanation check the thread comment below:
https://gitlab.isc.org/isc-projects/bind9/-/issues/1719#note_145857
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)
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)
After the network manager rewrite, tcp-higwater stats was only being
updated when a valid DNS query was received over tcp.
It turns out tcp-quota is updated right after a tcp connection is
accepted, before any data is read, so in the event that some client
connect but don't send a valid query, it wouldn't be taken into
account to update tcp-highwater stats, that is wrong.
This commit fix tcp-highwater to update its stats whenever a tcp connection
is established, independent of what happens after (timeout/invalid
request, etc).
- restore support for tcp-initial-timeout, tcp-idle-timeout,
tcp-keepalive-timeout and tcp-advertised-timeout configuration
options, which were ineffective previously.
- ns__client_request() is now called by netmgr with an isc_nmhandle_t
parameter. The handle can then be permanently associated with an
ns_client object.
- The task manager is paused so that isc_task events that may be
triggred during client processing will not fire until after the netmgr is
finished with it. Before any asynchronous event, the client MUST
call isc_nmhandle_ref(client->handle), to prevent the client from
being reset and reused while waiting for an event to process. When
the asynchronous event is complete, isc_nmhandle_unref(client->handle)
must be called to ensure the handle can be reused later.
- reference counting of client objects is now handled in the nmhandle
object. when the handle references drop to zero, the client's "reset"
callback is used to free temporary resources and reiniialize it,
whereupon the handle (and associated client) is placed in the
"inactive handles" queue. when the sysstem is shutdown and the
handles are cleaned up, the client's "put" callback is called to free
all remaining resources.
- because client allocation is no longer handled in the same way,
the '-T clienttest' option has now been removed and is no longer
used by any system tests.
- the unit tests require wrapping the isc_nmhandle_unref() function;
when LD_WRAP is supported, that is used. otherwise we link a
libwrap.so interposer library and use that.
The double-locked queue implementation is still currently in use
in ns_client, but will be replaced by a fetch-and-add array queue.
This commit moves it from queue.h to list.h so that queue.h can be
used for the new data structure, and clean up dependencies between
list.h and types.h. Later, when the ISC_QUEUE is no longer is use,
it will be removed completely.
This variable will report the maximum number of simultaneous tcp clients
that BIND has served while running.
It can be verified by running rndc status, then inspect "tcp high-water:
count", or by generating statistics file, rndc stats, then inspect the
line with "TCP connection high-water" text.
The tcp-highwater variable is atomically updated based on an existing
tcp-quota system handled in ns/client.c.
This commit changes the BIND cookie algorithms to match
draft-sury-toorop-dnsop-server-cookies-00. Namely, it changes the Client Cookie
algorithm to use SipHash 2-4, adds the new Server Cookie algorithm using SipHash
2-4, and changes the default for the Server Cookie algorithm to be siphash24.
Add siphash24 cookie algorithm, and make it keep legacy aes as
- if the TCP quota has been exceeded but there are no clients listening
for new connections on the interface, we can now force attachment to the
quota using isc_quota_force(), instead of carrying on with the quota not
attached.
- the TCP client quota is now referenced via a reference-counted
'ns_tcpconn' object, one of which is created whenever a client begins
listening for new connections, and attached to by members of that
client's pipeline group. when the last reference to the tcpconn
object is detached, it is freed and the TCP quota slot is released.
- reduce code duplication by adding mark_tcp_active() function
- convert counters to stdatomic
(cherry picked from commit a8dd133d270873b736c1be9bf50ebaa074f5b38f)
(cherry picked from commit 4a8fc979c4)
- ensure that tcpactive is cleaned up correctly when accept() fails.
- set 'client->tcpattached' when the client is attached to the tcpquota.
carry this value on to new clients sharing the same pipeline group.
don't call isc_quota_detach() on the tcpquota unless tcpattached is
set. this way clients that were allowed to accept TCP connections
despite being over quota (and therefore, were never attached to the
quota) will not inadvertently detach from it and mess up the
accounting.
- simplify the code for tcpquota disconnection by using a new function
tcpquota_disconnect().
- before deciding whether to reject a new connection due to quota
exhaustion, check to see whether there are at least two active
clients. previously, this was "at least one", but that could be
insufficient if there was one other client in READING state (waiting
for messages on an open connection) but none in READY (listening
for new connections).
- before deciding whether a TCP client object can to go inactive, we
must ensure there are enough other clients to maintain service
afterward -- both accepting new connections and reading/processing new
queries. A TCP client can't shut down unless at least one
client is accepting new connections and (in the case of pipelined
clients) at least one additional client is waiting to read.
(cherry picked from commit 427a2fb4d17bc04ca3262f58a9dcf5c93fc6d33e)
(cherry picked from commit 0896841272)
Track pipeline groups using a shared reference counter
instead of a linked list.
(cherry picked from commit 31f392db20207a1b05d6286c3c56f76c8d69e574)
(cherry picked from commit 2211120222)
the TCP client quota could still be ineffective under some
circumstances. this change:
- improves quota accounting to ensure that TCP clients are
properly limited, while still guaranteeing that at least one client
is always available to serve TCP connections on each interface.
- uses more descriptive names and removes one (ntcptarget) that
was no longer needed
- adds comments
(cherry picked from commit 9e74969f85329fe26df2fad390468715215e2edd)
(cherry picked from commit d7e84cee0b)
- named could return FORMERR if parsing iterative responses
ended with a result code such as DNS_R_OPTERR. instead of
computing a response code based on the result, in this case
we now just force the response to be SERVFAIL.
Implement a helper function which, given an input string:
- copies it verbatim if it contains at least one path separator,
- prepends the named plugin installation directory to it otherwise.
This function will allow configuration parsing code to conveniently
determine the full path to a plugin module given either a path or a
filename.
While other, simpler ways exist for making sure filenames passed to
dlopen() cause the latter to look for shared objects in a specific
directory, they are very platform-specific. Using full paths is thus
likely the most portable and reliable solution.
Also added unit tests for ns_plugin_expandpath() to ensure it behaves
as expected for absolute paths, relative paths, and filenames, for
various target buffer sizes.
(Note: plugins share a directory with named on Windows; there is no
default plugin path. Therefore the source path is copied to the
destination path with no modification.)
- "hook" is now used only for hook points and hook actions
- the "hook" statement in named.conf is now "plugin"
- ns_module and ns_modlist are now ns_plugin and ns_plugins
- ns_module_load is renamed ns_plugin_register
- the mandatory functions in plugin modules (hook_register,
hook_check, hook_version, hook_destroy) have been renamed
- use a per-view module list instead of global hook_modules
- create an 'instance' pointer when registering modules, store it in
the module structure, and use it as action_data when calling
hook functions - this enables multiple module instances to be set
up in parallel
- also some nomenclature changes and cleanup
- added some hook points that will be needed for a dns64 module later
- moved some code from the beginning of query_respond() to
the end of query_prepresponse(); this has no effect on functionality
but means we can have a hook point at the top of query_respond(),
which seems nicer
- compressed duplicated code into query_zerottl_refetch() function
- added a qctx->answered flag so that a module can prevent
query_addrrset() from being called from query_respond() when
it's already been called from the module.
- this is necessary because adding the same hook to multiple views
causes the ISC_LIST link value to become inconsistent; it isn't
noticeable when only one hook action is ever registered at a
given hook point, but it will break things when there are two.
- eliminate qctx->hookdata and client->hookflags.
- use a memory pool to allocate data blobs in the filter-aaaa module,
and associate them with the client address in a hash table
- instead of detaching the client in query_done(), mark it for deletion
and then call ns_client_detach() from qctx_destroy(); this ensures
that it will still exist when the QCTX_DESTROYED hook point is
reached.
