in the "refactor tcpquota and pipeline refs" commit, the counting
of active interfaces was tightened in such a way that named could
fail to listen on an interface if there were more interfaces than
tcp-clients. when checking the quota to start accepting on an
interface, if the number of active clients was above zero, then
it was presumed that some other client was able to handle accepting
new connections. this, however, ignored the fact that the current client
could be included in that count, so if the quota was already exceeded
before all the interfaces were listening, some interfaces would never
listen.
we now check whether the current client has been marked active; if so,
then the number of active clients on the interface must be greater
than 1, not 0.
(cherry picked from commit 02365b87ea0b1ea5ea8b17376f6734c811c95e61)
(cherry picked from commit cae79e1bab)
- 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)
tcp-clients settings could be exceeded in some cases by
creating more and more active TCP clients that are over
the set quota limit, which in the end could lead to a
DoS attack by e.g. exhaustion of file descriptors.
If TCP client we're closing went over the quota (so it's
not attached to a quota) mark it as mortal - so that it
will be destroyed and not set up to listen for new
connections - unless it's the last client for a specific
interface.
(cherry picked from commit eafcff07c25bdbe038ae1e4b6660602a080b9395)
(cherry picked from commit 9e7617cc84)
- Always set is_zonep in query_getdb; previously it was only set if
result was ISC_R_SUCCESS or ISC_R_NOTFOUND.
- Don't reset is_zone for redirect.
- Style cleanup.
(cherry picked from commit a85cc641d7a4c66cbde03cc4e31edc038a24df46)
(cherry picked from commit 486a201149)
Key IDs may accidentally match dig output that is not the key ID (for
example the RRSIG inception or expiration time, the query ID, ...).
Search for key ID + signer name should prevent that, as that is what
only should occur in the RRSIG record, and signer name always follows
the key ID.
Remove sleep calls from test, rely on wait_for_log(). Make
wait_for_log() and dnssec_loadkeys_on() fail the test if the
appropriate log line is not found.
Slightly adjust the echo_i() lines to print only the key ID (not the
key name).
One second may not be enough for an NSEC3 chain change triggered by an
UPDATE message to complete. Wait up to 10 seconds when checking whether
a given NSEC3 chain change is complete in the "nsupdate" system test.
In the "nsupdate" system test, do not sleep before checking results of
changes which are expected to be processed synchronously, i.e. before
nsupdate returns.
- 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.
Make bin/tests/system/ifconfig.bat also configure addresses ending with
9 and 10, so that the script is in sync with its Unix counterpart.
Update comments listing the interfaces created by ifconfig.{bat,sh} so
that they do not include addresses whose last octet is zero (since an
address like 10.53.1.0/24 is not a valid host address and thus the
aforementioned scripts do not even attempt configuring them).
On Windows, the bin/tests/system/dnssec/signer/example.db.signed file
contains carriage return characters at the end of each line. Remove
them before passing the aforementioned file to the awk script extracting
key IDs so that the latter can work properly.
As signals are currently not handled by named on Windows, instances
terminated using signals are not able to perform a clean shutdown, which
involves e.g. removing the lock file. Thus, waiting for a given
instance's lock file to be removed beforing assuming it is shut down
is pointless on Windows, so do not even attempt it.
When a Windows service receives a request to stop, it should not set its
state to SERVICE_STOPPED until it is completely shut down as doing that
allows the operating system to kill that service prematurely, which in
the case of named may e.g. prevent the PID file and/or the lock file
from being cleaned up.
Set service state to SERVICE_STOP_PENDING when named begins its shutdown
and only report the SERVICE_STOPPED state immediately before exiting.
Evan HuntandOndřej Surý
Michał KępieńandOndřej Surý
Witold KręcickiandOndřej Surý
Ondřej Surý
Matthijs MekkingandOndřej Surý
Mark Andrews