The flow of operations in dispatch is changing and will now be similar
for both UDP and TCP queries:
1) Call dns_dispatch_addresponse() to assign a query ID and register
that we'll be listening for a response with that ID soon. the
parameters for this function include callback functions to inform the
caller when the socket is connected and when the message has been
sent, as well as a task action that will be sent when the response
arrives. (later this could become a netmgr callback, but at this
stage to minimize disruption to the calling code, we continue to use
isc_task for the response event.) on successful completion of this
function, a dispatch entry object will be instantiated.
2) Call dns_dispatch_connect() on the dispatch entry. this runs
isc_nm_udpconnect() or isc_nm_tcpdnsconnect(), as needed, and begins
listening for responses. the caller is informed via a callback
function when the connection is established.
3) Call dns_dispatch_send() on the dispatch entry. this runs
isc_nm_send() to send a request.
4) Call dns_dispatch_removeresponse() to terminate listening and close
the connection.
Implementation comments below:
- As we will be using netmgr buffers now. code to send the length in
TCP queries has also been removed as that is handled by the netmgr.
- TCP dispatches can be used by multiple simultaneous queries, so
dns_dispatch_connect() now checks whether the dispatch is already
connected before calling isc_nm_tcpdnsconnect() again.
- Running dns_dispatch_getnext() from a non-network thread caused a
crash due to assertions in the netmgr read functions that appear to be
unnecessary now. the assertions have been removed.
- fctx->nqueries was formerly incremented when the connection was
successful, but is now incremented when the query is started and
decremented if the connection fails.
- It's no longer necessary for each dispatch to have a pool of tasks, so
there's now a single task per dispatch.
- Dispatch code to avoid UDP ports already in use has been removed.
- dns_resolver and dns_request have been modified to use netmgr callback
functions instead of task events. some additional changes were needed
to handle shutdown processing correctly.
- Timeout processing is not yet fully converted to use netmgr timeouts.
- Fixed a lock order cycle reported by TSAN (view -> zone-> adb -> view)
by by calling dns_zt functions without holding the view lock.
- Many dispatch attributes can be set implicitly instead of being passed
in. we can infer whether to set DNS_DISPATCHATTR_TCP or _UDP from
whether we're calling dns_dispatch_createtcp() or _createudp(). we
can also infer DNS_DISPATCHATTR_IPV4 or _IPV6 from the addresses or
the socket that were passed in.
- We no longer use dup'd sockets in UDP dispatches, so the 'dup_socket'
parameter has been removed from dns_dispatch_createudp(), along with
the code implementing it. also removed isc_socket_dup() since it no
longer has any callers.
- The 'buffersize' parameter was ignored and has now been removed;
buffersize is now fixed at 4096.
- Maxbuffers and maxrequests don't need to be passed in on every call to
dns_dispatch_createtcp() and _createudp().
In all current uses, the value for mgr->maxbuffers will either be
raised once from its default of 20000 to 32768, or else left
alone. (passing in a value lower than 20000 does not lower it.) there
isn't enough difference between these values for there to be any need
to configure this.
The value for disp->maxrequests controls both the quota of concurrent
requests for a dispatch and also the size of the dispatch socket
memory pool. it's not clear that this quota is necessary at all. the
memory pool size currently starts at 32768, but is sometimes lowered
to 4096, which is definitely unnecessary.
This commit sets both values permanently to 32768.
- Previously TCP dispatches allocated their own separate QID table,
which didn't incorporate a port table. this commit removes
per-dispatch QID tables and shares the same table between all
dispatches. since dispatches are created for each TCP socket, this may
speed up the dispatch allocation process. there may be a slight
increase in lock contention since all dispatches are sharing a single
QID table, but since TCP sockets are used less often than UDP
sockets (which were already sharing a QID table), it should not be a
substantial change.
- The dispatch port table was being used to determine whether a port was
already in use; if so, then a UDP socket would be bound with
REUSEADDR. this commit removes the port table, and always binds UDP
sockets that way.
Currently the netmgr doesn't support unconnected, shared UDP sockets, so
there's no reason to retain that functionality in the dispatcher prior
to porting to the netmgr.
In this commit, the DNS_DISPATCHATTR_EXCLUSIVE attribute has been
removed as it is now non-optional; UDP dispatches are alwasy exclusive.
Code implementing non-exclusive UDP dispatches has been removed.
dns_dispatch_getentrysocket() now always returns the dispsocket for UDP
dispatches and the dispatch socket for TCP dispatches.
There is no longer any need to search for existing dispatches from
dns_dispatch_getudp(), so the 'mask' option has been removed, and the
function renamed to the more descriptive dns_dispatch_createudp().
The DNS_REQUESTOPT_SHARE flag was added when client-side pipelining of
TCP queries was implemented. there was no need to make it optional;
forcing it to be in effect for all requests simplfiies the code.
- UDP buffersize is now established when creating dispatch manager
and is always set to 4096.
- Set up the default port range in dispatchmgr before setting the magic
number.
- Magic is not set until dispatchmgr is fully created.
This commit adds the ability to enable or disable stateless TLS
session resumption tickets (see RFC5077). Having this ability is
twofold.
Firstly, these tickets are encrypted by the server, and the algorithm
might be weaker than the algorithm negotiated during the TLS session
establishment (it is in general the case for TLSv1.2, but the generic
principle applies to TLSv1.3 as well, despite it having better ciphers
for session tickets). Thus, they might compromise Perfect Forward
Secrecy.
Secondly, disabling it might be necessary if the same TLS key/cert
pair is supposed to be used by multiple servers to achieve, e.g., load
balancing because the session ticket by default gets generated in
runtime, while to achieve successful session resumption ability, in
this case, would have required using a shared key.
The proper alternative to having the ability to disable stateless TLS
session resumption tickets is to implement a proper session tickets
key rollover mechanism so that key rotation might be performed
often (e.g. once an hour) to not compromise forward secrecy while
retaining the associated performance benefits. That is much more work,
though. On the other hand, having the ability to disable session
tickets allows having a deployable configuration right now in the
cases when either forward secrecy is wanted or sharing the TLS
key/cert pair between multiple servers is needed (or both).
This commit adds support for enforcing the preference of server
ciphers over the client ones. This way, the server attains control
over the ciphers priority and, thus, can choose more strong cyphers
when a client prioritises less strong ciphers over the more strong
ones, which is beneficial when trying to achieve Perfect Forward
Secrecy.
This commit adds support for setting TLS cipher list string in the
format specified in the OpenSSL
documentation (https://www.openssl.org/docs/man1.1.1/man1/ciphers.html).
The syntax of the cipher list is verified so that specifying the wrong
string will prevent the configuration from being loaded.
This commit adds support for loading DH-parameters (Diffie-Hellman
parameters) via the new "dhparam-file" option within "tls" clause. In
particular, Diffie-Hellman parameters are needed to enable the range
of forward-secrecy enabled cyphers for TLSv1.2, which are getting
silently disabled otherwise.
This commit adds the ability to specify allowed TLS protocols versions
within the "tls" clause. If an unsupported TLS protocol version is
specified in a file, the configuration file will not pass
verification.
Also, this commit adds strict checks for "tls" clauses verification,
in particular:
- it ensures that loading configuration files containing duplicated
"tls" clauses is not allowed;
- it ensures that loading configuration files containing "tls" clauses
missing "cert-file" or "key-file" is not allowed;
- it ensures that loading configuration files containing "tls" clauses
named as "ephemeral" or "none" is not allowed.
Previously a missing/deleted zone which was referenced by a catalog
zone was causing a crash when doing a reload.
This commit will make `named` to ignore the fact that the zone is
missing, and make sure to restore it later on.
This commit fixes heap use after free when checking BIND's
configuration files for errors with http clauses. The old code
was unnecessarially copying the http element name and freeing
it to early. The name is now used directly.
The old-style DLZ drivers were already marked as no longer actively
maintained and expected to be removed eventually. With the new automake
build system, the old-style DLZ drivers were not updated, and instead of
putting an effort into something that's not being maintained, let's
rather remove the unmaintained code.
Closes: #2814
Address the following warnings reported by PyLint 2.10.2:
************* Module tests-checkds
bin/tests/system/checkds/tests-checkds.py:70:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/checkds/tests-checkds.py:120:13: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/checkds/tests-checkds.py:206:17: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module yamlget
bin/tests/system/digdelv/yamlget.py:22:5: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module stress_http_quota
bin/tests/system/doth/stress_http_quota.py:131:13: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module tests-rpz-passthru-logging
bin/tests/system/rpzextra/tests-rpz-passthru-logging.py:40:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/rpzextra/tests-rpz-passthru-logging.py:44:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
- when transfer-source(-v6), query-source(-v6), notify-source(-v6)
or parental-source(-v6) are specified with a port number, issue a
warning.
- when the port specified is the same as the DNS listener port (i.e.,
53, or whatever was specified as "port" in "options"), issue a fatal
error.
- check that "port" is in range. (previously this was only checked
by named, not by named-checkconf.)
- added checkconf tests.
- incidental fix: removed dead code in check.c:bind9_check_namedconf().
(note: if the DNS port is specified on the command line with "named -p",
that is not conveyed to libbind9, so these checks will not take it into
account.)
The ns3->ns2 forwarding is now done using the IPv6 addresses, so we also
test that the query-source-v6 address is still operational after removal
of interface adjustment.
The native PKCS#11 support has been removed in favour of better
maintained, more performance and easier to use OpenSSL PKCS#11 engine
from the OpenSC project.
when "checking lame server clients are dropped below the hard limit",
periodically a query is sent for a name for which the server is
authoritative, to verify that legitimate queries can still be
processed while the server is dealing with a flood of lame delegation
queries. those queries used the same dig options as elsewhere in the
fetchlimit test, including "+tries=1 +timeout=1". on slow systems, a
1-second timeout may be insufficient to get an answer even if the server
is behaving well. this commit increases the timeout for the check
queries to 2 seconds in hopes that will be enough to eliminate test
failures in CI.
This commit modifies the MTU of the loopback interface on
Linux systems to 1500, so that oversized UDP packets can
trigger EMSGSIZE errors, and tests that named handles
such errors correctly.
Note that the loopback MTU size has not yet been modified
for other platforms.
This commit ensures that DoH (and DoT) functionality works well via
IPv6 as well.
The changes were made because it turned out that dig could not make
DoH queries against an IPv6 IP address. These tests ensure that such a
bug will not remain unnoticed.
The commit also increases the servers' startup timeout to 25 seconds
because the initial timeout of 14 seconds was too short to generate
(!) eight 4096 bit ephemeral RSA certificates on a heavily loaded CI
runner in some pipeline runs.
This commit adds new function isc_nm_http_makeuri() which is supposed
to unify DoH URI construction throughout the codebase.
It handles IPv6 addresses, hostnames, and IPv6 addresses given as
hostnames properly, and replaces similar ad-hoc code in the codebase.
- removed unused functions
- changed some public functions to static that are never called
from outside client.c
- removed unused types and function prototypes
- renamed dns_client_destroy() to dns_client_detach()
The previous versions of BIND 9 exported its internal libraries so that
they can be used by third-party applications more easily. Certain
library functions were altered from specific BIND-only behavior to more
generic behavior when used by other applications.
This commit removes the function isc_lib_register() that was used by
external applications to enable the functionality.
test server now has tcp-idle-timeout set to 5 seconds and
tcp-keepalive-timeout set to 7, so queries that follow a 6-second sleep
should either succeed or fail depending on whether the keepalive option
was sent.
Add a statschannel test case to confirm that when keys are removed
(in this case because of a dnssec-policy change), the corresponding
dnssec-sign stats are cleared and are no longer shown in the
statistics.
Add a test case that has more than four keys (the initial number of
key slots that are created for dnssec-sign statistics). We shouldn't
be expecting weird values.
This fixes some errors in the manykeys zone configuration (keys
were created for algorithm RSASHA256, but the policy expected RSASHA1,
and the zone was not allowing dynamic updates).
This also fixes an error in the calls to 'zones-json.pl': The perl
script excepts an index number where the zone can be found, rather
than the zone name.
Add a test case for migrating CSK to dnssec-policy. The keymgr has no
way of telling that the key is used as a CSK, but if there is only one
key to migrate it is going to assume it must be a CSK.
