- restore support for tcp-initial-timeout, tcp-idle-timeout,
tcp-keepalive-timeout and tcp-advertised-timeout configuration
options, which were ineffective previously.
- add timeout support for TCP and TCPDNS connections to protect against
slowloris style attacks. currently, all timeouts are hard-coded.
- rework and simplify the TCPDNS state machine.
isc_mem_traceflag_test messes with stdout/stderr, which can cause
problems with subsequent tests (no output, libuv problems). Moving that
test case to the end ensures there are no side effects.
close the uv_handle for the worker async channel, and call
uv_loop_close() on shutdown to ensure that the event loop's
internal resources are properly freed.
when the TCPDNS_CLIENTS_PER_CONN limit has been exceeded for a TCP
DNS connection, switch to sequential mode to ensure that memory cannot
be exhausted by too many simultaneous queries.
- the netmgr was not correctly being specified when creating the task
manager, and was cleaned up in the wrong order when shutting down.
- on freebsd, timer_test appears to be prone to failure if the
netmgr is set up and torn down before and after ever test case, but
less so if it's only set up once at the beginning and once at the
end.
This commit renames isctest {mctx,lctx} to test_{mctx,lctx} and cleans
up their usage in the individual unit tests. This allows embedding
library .c files directly into the unit tests.
This allows a task to be temporary disabled so that objects won't be
processed simultaneously by libuv events and isc_task events. When a
task is paused, currently running events may complete, but no further
event will added to the run queue will be executed until the task is
unpaused.
When a task manager is created, we can now specify an `isc_nm`
object to associate with it; thereafter when the task manager is
placed into exclusive mode, the network manager will be paused.
This is a replacement for the existing isc_socket and isc_socketmgr
implementation. It uses libuv for asynchronous network communication;
"networker" objects will be distributed across worker threads reading
incoming packets and sending them for processing.
UDP listener sockets automatically create an array of "child" sockets
so each worker can listen separately.
TCP sockets are shared amongst worker threads.
A TCPDNS socket is a wrapper around a TCP socket, which handles the
the two-byte length field at the beginning of DNS messages over TCP.
(Other wrapper socket types can be implemented in the future to handle
DNS over TLS, DNS over HTTPS, etc.)
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.
glibc 2.30 deprecated the <sys/sysctl.h> header [1]. However, that
header is still used on other Unix-like systems, so only prevent it from
being used on Linux, in order to prevent compiler warnings from being
triggered.
[1] https://sourceware.org/ml/libc-alpha/2019-08/msg00029.html
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.
cppcheck 1.89 enabled certain value flow analysis mechanisms [1] which
trigger null pointer dereference false positives in lib/dns/rpz.c:
lib/dns/rpz.c:582:7: warning: Possible null pointer dereference: tgt_ip [nullPointer]
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:1419:44: note: Calling function 'adj_trigger_cnt', 4th argument 'NULL' value is 0
adj_trigger_cnt(rpzs, rpz_num, rpz_type, NULL, 0, true);
^
lib/dns/rpz.c:582:7: note: Null pointer dereference
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:596:7: warning: Possible null pointer dereference: tgt_ip [nullPointer]
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:1419:44: note: Calling function 'adj_trigger_cnt', 4th argument 'NULL' value is 0
adj_trigger_cnt(rpzs, rpz_num, rpz_type, NULL, 0, true);
^
lib/dns/rpz.c:596:7: note: Null pointer dereference
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:610:7: warning: Possible null pointer dereference: tgt_ip [nullPointer]
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:1419:44: note: Calling function 'adj_trigger_cnt', 4th argument 'NULL' value is 0
adj_trigger_cnt(rpzs, rpz_num, rpz_type, NULL, 0, true);
^
lib/dns/rpz.c:610:7: note: Null pointer dereference
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
It seems that cppcheck no longer treats at least some REQUIRE()
assertion failures as fatal, so add extra assertion macro definitions to
lib/isc/include/isc/util.h that are only used when the CPPCHECK
preprocessor macro is defined; these definitions make cppcheck 1.89
behave as expected.
There is an important requirement for these custom definitions to work:
cppcheck must properly treat abort() as a function which does not
return. In order for that to happen, the __GNUC__ macro must be set to
a high enough number (because system include directories are used and
system headers compile attributes away if __GNUC__ is not high enough).
__GNUC__ is thus set to the major version number of the GCC compiler
used, which is what that latter does itself during compilation.
[1] aaeec462e6
