Commit graph

2426 commits

Author SHA1 Message Date
Ondřej Surý
ab528a0fcb Add isc_rwlock around dns_aclenv .localhost and .localnets member
In order to modify the .localhost and .localnets members of the
dns_aclenv, all other processing on the netmgr loops needed to be
stopped using the task exclusive mode.  Add the isc_rwlock to the
dns_aclenv, so any modifications to the .localhost and .localnets can be
done under the write lock.

(cherry picked from commit 8138a595d9)
2022-04-26 14:21:57 +02:00
Aram Sargsyan
c37a75df5d Implement catalog zones change of ownership (coo) support
Catalog zones change of ownership is special mechanism to facilitate
controlled migration of a member zone from one catalog to another.

It is implemented using catalog zones property named "coo" and is
documented in DNS catalog zones draft version 5 document.

Implement the feature using a new hash table in the catalog zone
structure, which holds the added "coo" properties for the catalog zone
(containing the target catalog zone's name), and the key for the hash
table being the member zone's name for which the "coo" property is being
created.

Change some log messages to have consistent zone name quoting types.

Update the ARM with change of ownership documentation and usage
examples.

Add tests which check newly the added features.

(cherry picked from commit bb837db4ee)
2022-04-14 20:53:31 +00:00
Matthijs Mekking
c3ab09deb5 Update dns_dnssec_syncdelete() function
Update the function that synchronizes the CDS and CDNSKEY DELETE
records. It now allows for the possibility that the CDS DELETE record
is published and the CDNSKEY DELETE record is not, and vice versa.

Also update the code in zone.c how 'dns_dnssec_syncdelete()' is called.

With KASP, we still maintain the DELETE records our self. Otherwise,
we publish the CDS and CDNSKEY DELETE record only if they are added
to the zone. We do still check if these records can be signed by a KSK.

This change will allow users to add a CDS and/or CDNSKEY DELETE record
manually, without BIND removing them on the next zone sign.

Note that this commit removes the check whether the key is a KSK, this
check is redundant because this check is also made in
'dst_key_is_signing()' when the role is set to DST_BOOL_KSK.

(cherry picked from commit 3d05c99abb)
2022-04-13 14:43:40 +02:00
Ondřej Surý
25bc461446 Revert "General cleanup of dns_rpz implementation"
This reverts commit bfee462403.
2022-04-06 10:42:29 +02:00
Ondřej Surý
242500909a Revert "Refactor the dns_rpz_add/delete to use local rpz copy"
This reverts commit f4cba0784e.
2022-04-06 10:42:22 +02:00
Ondřej Surý
9b78612e7d Revert "Run the RPZ update as offloaded work"
This reverts commit e128b6a951.
2022-04-06 10:30:06 +02:00
Ondřej Surý
e128b6a951 Run the RPZ update as offloaded work
Previously, the RPZ updates ran quantized on the main nm_worker loops.
As the quantum was set to 1024, this might lead to service
interruptions when large RPZ update was processed.

Change the RPZ update process to run as the offloaded work.  The update
and cleanup loops were refactored to do as little locking of the
maintenance lock as possible for the shortest periods of time and the db
iterator is being paused for every iteration, so we don't hold the rbtdb
tree lock for prolonged periods of time.

(cherry picked from commit f106d0ed2b)
2022-04-04 22:59:59 +02:00
Ondřej Surý
f4cba0784e Refactor the dns_rpz_add/delete to use local rpz copy
Previously dns_rpz_add() were passed dns_rpz_zones_t and index to .zones
array.  Because we actually attach to dns_rpz_zone_t, we should be using
the local pointer instead of passing the index and "finding" the
dns_rpz_zone_t again.

Additionally, dns_rpz_add() and dns_rpz_delete() were used only inside
rpz.c, so make them static.

(cherry picked from commit b6e885c97f)
2022-04-04 22:59:59 +02:00
Ondřej Surý
bfee462403 General cleanup of dns_rpz implementation
Do a general cleanup of lib/dns/rpz.c style:

 * Removed deprecated and unused functions
 * Unified dns_rpz_zone_t naming to rpz
 * Unified dns_rpz_zones_t naming to rpzs
 * Add and use rpz_attach() and rpz_attach_rpzs() functions
 * Shuffled variables to be more local (cppcheck cleanup)

(cherry picked from commit 840179a247)
2022-04-04 22:59:59 +02:00
Ondřej Surý
ebe2baec95 Make dns_catz_get_iterator() return void
Previously, the function(s) in the commit subject could fail for various
reasons - mostly allocation failures, or other functions returning
different return code than ISC_R_SUCCESS.  Now, the aforementioned
function(s) cannot ever fail and they would always return ISC_R_SUCCESS.

Change the function(s) to return void and remove the extra checks in
the code that uses them.

(cherry picked from commit d128656d2e)
2022-03-08 20:47:06 +01:00
Ondřej Surý
aed1a0497d Remove unused dns_timer API
The dns_timer API was unused, and this commit just removes it.

(cherry picked from commit cdce681cf7)
2022-02-16 11:07:04 +01:00
Evan Hunt
8bd431a251 update dlz_minimal.h
the addition of support for ECS client information in DLZ
modules omitted some necessary changes to build modules
in contrib.

(cherry picked from commit d3fed6f400)
2022-01-27 16:18:34 -08:00
Evan Hunt
317ef804c0 allow dns_clientinfo to store client ECS data
this brings DNS_CLIENTINFO_VERSION into line with the subscription
branch so that fixes applied to clientinfo processing can also be
applied to the main branch without diverging.

(cherry picked from commit 737e658602)
2022-01-27 14:51:11 -08:00
Ondřej Surý
58bd26b6cf Update the copyright information in all files in the repository
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.
2022-01-11 09:05:02 +01:00
Ondřej Surý
f326d45135 Lock view while accessing its zone table
Commit 308bc46a59 introduced a change to
the view_flushanddetach() function which makes the latter access
view->zonetable without holding view->lock.  As confirmed by TSAN, this
enables races between threads for view->zonetable accesses.

Swap the view->zonetable pointer under view lock and then detach the
local swapped dns_zt_t later when the view lock is already unlocked.

This commit also changes the dns_zt interfaces, so the setting the
zonetable "flush" flag is separate operation to dns_zt_detach,
e.g. instead of doing:

    if (view->flush) {
        dns_zt_flushanddetach(&zt);
    } else {
        dns_zt_detach(&zt);
    }

the code is now:

    if (view->flush) {
        dns_zt_flush(zt);
    }
    dns_zt_detach(&zt);

making the code more consistent with how we handle flushing and
detaching dns_zone_t pointers from the view.
2022-01-05 16:56:16 +01:00
Artem Boldariev
64f7c55662 Use the TLS context cache for client-side contexts (XoT)
This commit enables client-side TLS contexts re-use for zone transfers
over TLS. That, in turn, makes it possible to use the internal session
cache associated with the contexts, allowing the TLS connections to be
established faster and requiring fewer resources by not going through
the full TLS handshake procedure.

Previously that would recreate the context on every connection, making
TLS session resumption impossible.

Also, this change lays down a foundation for Strict TLS (when the
client validates a server certificate), as the TLS context cache can
be extended to store additional data required for validation (like
intermediates CA chain).
2021-12-29 10:25:15 +02:00
Mark Andrews
dc8595936c remove broken-nsec and reject-000-label options 2021-12-23 15:13:46 +11:00
Mark Andrews
0aaaa8768f
Reject NSEC records with next field with \000 label
A number of DNS implementation produce NSEC records with bad type
maps that don't contain types that exist at the name leading to
NODATA responses being synthesize instead of the records in the
zone.  NSEC records with these bad type maps often have the NSEC
NSEC field set to '\000.QNAME'.  We look for the first label of
this pattern.

e.g.
	example.com NSEC \000.example.com SOA NS NSEC RRSIG
	example.com RRRSIG NSEC ...
	example.com SOA ...
	example.com RRRSIG SOA ...
	example.com NS ...
	example.com RRRSIG NS ...
	example.com A ...
	example.com RRRSIG A ...

	A is missing from the type map.

This introduces a temporary option 'reject-000-label' to control
this behaviour.
2021-12-02 14:27:18 +01:00
Mark Andrews
733f58a7a5
Allow servers that emit broken NSEC records to be identified
'server <prefix> { broken-nsec yes; };' can now be used to stop
NSEC records from negative responses from servers in the given
prefix being cached and hence available to synth-from-dnssec.
2021-12-02 14:27:14 +01:00
Mark Andrews
8ff2c133b5
Add dns_nsec_requiredtypespresent
checks an NSEC rdataset to ensure that both NSEC and RRSIG are
present in the type map.  These types are required for the NSEC
to be valid
2021-12-02 14:18:42 +01:00
Mark Andrews
43316a40a0
Record how often DNS_R_COVERINGNSEC is returned from the cache
reported as "covering nsec returned" when dumping cache stats
and as "CoveringNSEC" in json and xml cache statistics.
2021-12-02 14:18:41 +01:00
Mark Andrews
85bfcaeb2e
Extend dns_db_nodecount to access auxilary rbt node counts
dns_db_nodecount can now be used to get counts from the auxilary
rbt databases.  The existing node count is returned by
tree=dns_dbtree_main.  The nsec and nsec3 node counts by dns_dbtree_nsec
and dns_dbtree_nsec3 respectively.
2021-12-02 14:18:41 +01:00
Artem Boldariev
7843fb4ece XoT: add support for client-side TLS parameters
This commit adds support for client-side TLS parameters to XoT.

Prior to this commit all client-side TLS contexts were using default
parameters only, ignoring the options from the BIND's configuration
file.

Currently, the following 'tls' parameters are supported:

- protocols;
- ciphers;
- prefer-server-ciphers.
2021-12-01 12:00:28 +02:00
Artem Boldariev
0ee6f66cbd Integrate extended ACLs syntax featuring 'port' and 'transport' opts
This commit completes the integration of the new, extended ACL syntax
featuring 'port' and 'transport' options.

The runtime presentation and ACL loading code are extended to allow
the syntax to be used beyond the 'allow-transfer' option (e.g. in
'acl' definitions and other 'allow-*' options) and can be used to
ultimately extend the ACL support with transport-only
ACLs (e.g. 'transport-acl tls-acl port 853 transport tls'). But, due
to fundamental nature of such a change, it has not been completed as a
part of 9.17.X release series due to it being close to 9.18 stable
release status. That means that we do not have enough time to fully
test it.

The complete integration is planned as a part of 9.19.X release
series.

The code was manually verified to work as expected by temporarily
enabling the extended syntax for 'acl' statements and 'allow-query'
options, including ACL merging, negated ACLs.
2021-11-30 12:20:22 +02:00
Aram Sargsyan
43ac2cd229 Fix catalog zone reconfiguration crash
The following scenario triggers a "named" crash:

1. Configure a catalog zone.
2. Start "named".
3. Comment out the "catalog-zone" clause.
4. Run `rndc reconfig`.
5. Uncomment the "catalog-zone" clause.
6. Run `rndc reconfig` again.

Implement the required cleanup of the in-memory catalog zone during
the first `rndc reconfig`, so that the second `rndc reconfig` could
find it in an expected state.
2021-11-23 11:39:37 +00:00
Matthijs Mekking
6c8fc2f4f0 Add method to set extended DNS error
Add a new parameter to 'ns_client_t' to store potential extended DNS
error. Reset when the client request ends, or is put back.

Add defines for all well-known info-codes.

Update the number of DNS_EDNSOPTIONS that we are willing to set.

Create a new function to set the extended error for a client reply.
2021-11-19 09:44:28 +01:00
Artem Boldariev
51a2c7aed3 DoH: Set the "max-age" "Cache-Control" HTTP header value
This commit makes BIND set the "max-age" value of the "Cache-Control"
HTTP header to the minimal TTL from the Answer section for positive
answers, as RFC 8484 advises in section 5.1.

We calculate the minimal TTL as a side effect of rendering the
response DNS message, so it does not change the code flow much, nor
should it have any measurable negative impact on the performance.

For negative answers, the "max-age" value is set using the TTL and
SOA-minimum values from an SOA record in the Authority section.
2021-11-05 14:14:59 +02:00
Evan Hunt
a55589f881 remove all references to isc_socket and related types
Removed socket.c, socket.h, and all references to isc_socket_t,
isc_socketmgr_t, isc_sockevent_t, etc.
2021-10-15 01:01:25 -07:00
Mark Andrews
93279bb4b3 Add {krb5,ms}-subdomain-self-rhs update policy rules
The new rules compare the target name in PTR and SRV records against
the machine name embedded in the kerberos principal.  This can be
used to further restrict what PTR and SRV records can be added or
deleted via dynamic updates if desired.
2021-10-15 11:18:41 +11:00
Ondřej Surý
8be27b308f Remove unused LIBRPZ_(UN)LIKELY macros
The librpz.h defined LIRPZ_LIKELY() and LIBRPZ_UNLIKELY() macros that
were actually unused in the code.  Remove the macros and the autoconf
check for __builtin_expect().
2021-10-14 15:22:57 +02:00
Ondřej Surý
f3635bcc14 Use #pragma once as header guards
Unify the header guard style and replace the inconsistent include guards
with #pragma once.

The #pragma once is widely and very well supported in all compilers that
BIND 9 supports, and #pragma once was already in use in several new or
refactored headers.

Using simpler method will also allow us to automate header guard checks
as this is simpler to programatically check.

For reference, here are the reasons for the change taken from
Wikipedia[1]:

> In the C and C++ programming languages, #pragma once is a non-standard
> but widely supported preprocessor directive designed to cause the
> current source file to be included only once in a single compilation.
>
> Thus, #pragma once serves the same purpose as include guards, but with
> several advantages, including: less code, avoidance of name clashes,
> and sometimes improvement in compilation speed. On the other hand,
> #pragma once is not necessarily available in all compilers and its
> implementation is tricky and might not always be reliable.

1. https://en.wikipedia.org/wiki/Pragma_once
2021-10-13 00:49:15 -07:00
Ondřej Surý
edfae82c82 dns/resolver.c: Return void when ISC_R_SUCCESS is only returned value
With isc_mem_get() and dns_name_dup() no longer being able to fail, some
functions can now only return ISC_R_SUCCESS.  Change the return type to
void for the following function(s):

 * dns_zone_setprimaries()
 * dns_zone_setparentals()
 * dns_zone_setparentals()
 * dns_zone_setalsonotify()
2021-10-13 05:48:51 +02:00
Ondřej Surý
f51a9d834c dns/view.c: Return void when ISC_R_SUCCESS is only returned value
With isc_mem_get() and dns_name_dup() no longer being able to fail, some
functions can now only return ISC_R_SUCCESS.  Change the return type to
void for the following function(s):

 * dns_view_adddelegationonly()
 * dns_view_excludedelegationonly()
2021-10-13 05:47:48 +02:00
Ondřej Surý
8fb4c5bb7a dns/ssu.c: Return void when ISC_R_SUCCESS is only returned value
With isc_mem_get() and dns_name_dup() no longer being able to fail, some
functions can now only return ISC_R_SUCCESS.  Change the return type to
void for the following function(s):

 * dns_ssutable_addrule()
 * dns_ssutable_create()
 * dns_ssutable_createdlz()
2021-10-13 05:47:48 +02:00
Ondřej Surý
ecb74bae0d dns/resolver.c: Return void when ISC_R_SUCCESS is only returned value
With isc_mem_get() and dns_name_dup() no longer being able to fail, some
functions can now only return ISC_R_SUCCESS.  Change the return type to
void for the following function(s):

 * dns_resolver_addalternate()
2021-10-13 05:47:48 +02:00
Ondřej Surý
ee735ba79d dns/catz.c: Return void when ISC_R_SUCCESS is only returned value
With isc_mem_get() and dns_name_dup() no longer being able to fail, some
functions can now only return ISC_R_SUCCESS.  Change the return type to
void for the following function(s):

 * dns_catz_options_copy()
 * dns_catz_options_setdefault()
 * dns_catz_entry_new()
 * dns_catz_entry_copy()
2021-10-13 05:47:48 +02:00
Matthijs Mekking
2af05beafa Replace "master/slave" terms in code
Replace some "master/slave" terminology in the code with the preferred
"primary/secondary" keywords. This also changes user output such as
log messages, and fixes a typo ("seconary") in cfg_test.c.

There are still some references to "master" and "slave" for various
reasons:

- The old syntax can still be used as a synonym.
- The master syntax is kept when it refers to master files and formats.
- This commit replaces mainly keywords that are local. If "master" or
  "slave" is used in for example a structure that is all over the
  place, it is considered out of scope for the moment.
2021-10-12 13:11:13 -07:00
Matthijs Mekking
71b92d4d19 Replace "master/slave" terms in code comments
Replace those terms with the preferred "primary/secondary" keywords.
2021-10-12 13:09:00 -07:00
Ondřej Surý
8c819ec366 dns/rbt.c: Implement incremental hash table resizing
Originally, the hash table used in RBT database would be resized when it
reached certain number of elements (defined by overcommit).  This was
causing resolution brownouts for busy resolvers, because the rehashing
could take several seconds to complete.  This was mitigated by
pre-allocating the hash table in the RBT database used for caching to be
large-enough as determined by max-cache-size.  The downside of this
solution was that the pre-allocated hash table could take a significant
chunk of the memory even when the resolver cache would be otherwise
empty because the default value for max-cache-size is 90% of available
memory.

Implement incremental resizing[1] to perform the rehashing gradually:

 1. During the resize, allocate the new hash table, but keep the old
    table unchanged.
 2. In each lookup or delete operation, check both tables.
 3. Perform insertion operations only in the new table.
 4. At each insertion also move r elements from the old table to the new
    table.
 5. When all elements are removed from the old table, deallocate it.

To ensure that the old table is completely copied over before the new
table itself needs to be enlarged, it is necessary to increase the
size of the table by a factor of at least (r + 1)/r during resizing.

In our implementation r is equal to 1.

The downside of this approach is that the old table and the new table
could stay in memory for longer when there are no new insertions into
the hash table for prolonged periods of time as the incremental
rehashing happens only during the insertions.

The upside of this approach is that it's no longer necessary to
pre-allocate large hash table, because the RBT hash table rehashing
doesn't cause resolution brownouts anymore and thus we can use the
memory as needed.

1. https://en.m.wikipedia.org/wiki/Hash_table#Dynamic_resizing
2021-10-12 15:01:53 +02:00
Ondřej Surý
ed95f9fba3 Update the source code formatting using clang-format-13
clang-format-13 fixed some of the formatting that clang-format-12 got
wrong.  Update the formatting.
2021-10-12 11:14:40 +02:00
Ondřej Surý
2e3a2eecfe Make isc_result a static enum
Remove the dynamic registration of result codes.  Convert isc_result_t
from unsigned + #defines into 32-bit enum type in grand unified
<isc/result.h> header.  Keep the existing values of the result codes
even at the expense of the description and identifier tables being
unnecessary large.

Additionally, add couple of:

    switch (result) {
    [...]
    default:
        break;
    }

statements where compiler now complains about missing enum values in the
switch statement.
2021-10-06 11:22:20 +02:00
Evan Hunt
24dbf9849e refactor dispatch cancellation
Renamed some functions for clarity and readability:

- dns_dispatch_addresponse() -> dns_dispatch_add()
- dns_dispatch_removeresponse() -> dns_dispatch_done()

The dns_dispatch_cancel() function now calls dns_dispatch_done()
directly, so it is no longer ever necessary to call both functions.

dns_dispatch_cancel() is used to terminate dispatch connections
that are still pending, while dns_dispatch_done() is used when they
are complete.
2021-10-05 10:18:48 -07:00
Evan Hunt
cd8a081a4f Remove libdns init/shutdown functions
as libdns is no longer exported, it's not necessary to have
init and shutdown functions. the only purpose they served
was to create a private mctx and run dst_lib_init(), which
can be called directly instead.
2021-10-04 13:57:32 -07:00
Evan Hunt
8551ad026f dispatch: Fix several connect-related issues
- startrecv() and getnext() have been rewritten.

- Don't set TCP flag when connecting a UDP dispatch.

- Prevent TCP connections from trying to connect twice.

- dns_dispatch_gettcp() can now find a matching TCP dispatch that has
  not yet fully connected, and attach to it.  when the connection is
  completed, the connect callbacks are run for all of the pending
  entries.

- An atomic 'state' variable is now used for connection state instead of
  attributes.

- When dns_dispatch_cancel() is called on a TCP dispatch entry, only
  that one entry is canceled. the dispatch itself should not be shut
  down until there are no dispatch entries left associated with it.

- Other incidental cleanup, including removing DNS_DISPATCHATTR_IPV4 and
  _IPV6 (they were being set in the dispatch attributes but never used),
  cleaning up dns_requestmgr_create(), and renaming dns_dispatch_read()
  to the more descriptive dns_dispatch_resume().
2021-10-02 11:39:56 -07:00
Ondřej Surý
e317386090 dispatch: Remove 'timeout' callback
- It is no longer necessary to pass a 'timeout' callback to
  dns_dispatch_addresponse(); timeouts are handled directly by the
  'response' callback instead.

- The netmgr handle is no longer passed to dispatch callbacks, since
  they don't (and can't) use it. instead, dispatch_cb_t now takes a
  result code, region, and argument.

- Cleaned up timeout-related tests in dispatch_test.c
2021-10-02 11:39:56 -07:00
Evan Hunt
8b532d2e64 dispatch: Refactor to eliminate dns_dispatchevent
- Responses received by the dispatch are no longer sent to the caller
  via a task event, but via a netmgr-style recv callback.  the 'action'
  parameter to dns_dispatch_addresponse() is now called 'response' and
  is called directly from udp_recv() or tcp_recv() when a valid response
  has been received.

- All references to isc_task and isc_taskmgr have been removed from
  dispatch functions.

- All references to dns_dispatchevent_t have been removed and the type
  has been deleted.

- Added a task to the resolver response context, to be used for fctx
  events.

- When the caller cancels an operation, the response handler will be
  called with ISC_R_CANCELED; it can abort immediately since the caller
  will presumably have taken care of cleanup already.

- Cleaned up attach/detach in resquery and request.
2021-10-02 11:39:56 -07:00
Evan Hunt
81a22cbf5f Remove DISPATH_TRACE, RESOLVER_TRACE and REQ_TRACE logging
Remove the debugging printfs. (leaving this as a separate commit rather
than squashing it so we can restore it in the future if we ever need it
again.)
2021-10-02 11:39:56 -07:00
Evan Hunt
7dc54fa6f2 Refactor dispatch, resolver and request
Since every dispsock was associated with a dispentry anyway (though not
always vice versa), the members of dispsock have been combined into
dispentry, which is now reference-counted.  dispentry objects are now
attached before connecting and detached afterward to prevent races
between the connect callback and dns_dispatch_removeresponse().

Dispatch and dispatchmgr objects are now reference counted as well, and
the shutdown process has been simplified.  reference counting of
resquery and request objects has also been cleaned up significantly.

dns_dispatch_cancel() now flags a dispentry as having been canceled, so
that if the connect callback runs after cancellation, it will not
initiate a read.

The isblackholed() function has been simplified.
2021-10-02 11:39:56 -07:00
Evan Hunt
08ce69a0ea Rewrite dns_resolver and dns_request to use netmgr timeouts
- The `timeout_action` parameter to dns_dispatch_addresponse() been
  replaced with a netmgr callback that is called when a dispatch read
  times out.  this callback may optionally reset the read timer and
  resume reading.

- Added a function to convert isc_interval to milliseconds; this is used
  to translate fctx->interval into a value that can be passed to
  dns_dispatch_addresponse() as the timeout.

- Note that netmgr timeouts are accurate to the millisecond, so code to
  check whether a timeout has been reached cannot rely on microsecond
  accuracy.

- If serve-stale is configured, then a timeout received by the resolver
  may trigger it to return stale data, and then resume waiting for the
  read timeout. this is no longer based on a separate stale timer.

- The code for canceling requests in request.c has been altered so that
  it can run asynchronously.

- TCP timeout events apply to the dispatch, which may be shared by
  multiple queries.  since in the event of a timeout we have no query ID
  to use to identify the resp we wanted, we now just send the timeout to
  the oldest query that was pending.

- There was some additional refactoring in the resolver: combining
  fctx_join() and fctx_try_events() into one function to reduce code
  duplication, and using fixednames in fetchctx and fetchevent.

- Incidental fix: new_adbaddrinfo() can't return NULL anymore, so the
  code can be simplified.
2021-10-02 11:39:56 -07:00
Evan Hunt
308bc46a59 Convert dispatch to netmgr
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.
2021-10-02 11:39:56 -07:00