Your message dated Wed, 2 Feb 2022 16:41:08 +0100
with message-id <yfqmfedfnoynj...@x260.cruise.homelinux.net>
and subject line Re: Bug#765353: python-twisted-names: twisted.names.server
never truncates UDP responses
has caused the Debian Bug report #765353,
regarding python-twisted-names: twisted.names.server never truncates UDP
responses
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact ow...@bugs.debian.org
immediately.)
--
765353: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=765353
Debian Bug Tracking System
Contact ow...@bugs.debian.org with problems
--- Begin Message ---
Package: python-twisted-names
Version: 14.0.2-2
Severity: grave
Tags: patch
Justification: renders package unusable
Dear Maintainers,
Upstream bug: http://twistedmatrix.com/trac/ticket/6949
When using twisted.names.client to request a large number of DNS-SD records,
whose answer exceeds the UDP limit (512B), the message has to be remade using
TCP. This makes twisted.names useless for this use and many others cases as
soon as the response is too large.
I already proposed a patch June 13th, 2014 (4 months ago), without reaction
since now.
=== PATCH STARTS HERE
Description: twisted.names.server never truncates datagram responses #6949
Upstream bug: http://twistedmatrix.com/trac/ticket/6949
.
Until it supports wiki:EDNS0, twisted.names.server ought to limit the size of
its response messages to 512B.
.
But because of the way dns.Message.decode sets the maxSize=0 and because of the
way server re-uses the request message for its responses, it never actually
truncates large messages.
.
This probably means that some responses will be dropped or fragmented on their
route across the Internet, which means that clients have to wait for a timeout
before re-issuing the query over TCP.
.
twisted (14.0.2-2) unstable; urgency=medium
.
Author: Philippe Goetz <philippe.go...@siemens.com>
---
Origin: other, <url of original patch>
Bug: http://twistedmatrix.com/trac/ticket/6949
Bug-Debian: http://bugs.debian.org/<bugnumber>
Bug-Ubuntu: https://launchpad.net/bugs/<bugnumber>
Forwarded: <no|not-needed|url proving that it has been forwarded>
Reviewed-By: <name and email of someone who approved the patch>
Last-Update: <YYYY-MM-DD>
--- twisted-14.0.2.orig/twisted/names/dns.py
+++ twisted-14.0.2/twisted/names/dns.py
@@ -2738,6 +2738,9 @@ class DNSDatagramProtocol(DNSMixin, prot
m = Message()
try:
m.fromStr(data)
+ m.maxSize = min(512, self.transport.maxPacketSize)
+ if m.trunc:
+ m.trunc = addr # will be used for TCP
except EOFError:
log.msg("Truncated packet (%d bytes) from %s" % (len(data), addr))
return
--- twisted-14.0.2.orig/twisted/names/client.py
+++ twisted-14.0.2/twisted/names/client.py
@@ -369,7 +369,24 @@ class Resolver(common.ResolverBase):
the answers section, the authority section, and the additional section.
"""
if message.trunc:
- return
self.queryTCP(message.queries).addCallback(self.filterAnswers)
+ timeout = 10
+ if isinstance(message.trunc, tuple):
+ # Truncated message got from UDP server as trunc is an address
and not a bool
+ # NOTE: UDP server should be also a TCP server (on the address
and port) as required by RFCs
+ addr = message.trunc
+ # Try to reuse a connection already established with the server
+ for connection in self.connections:
+ if connection.transport.addr == addr:
+ return connection.query(message.queries,
timeout).addCallback(self.filterAnswers)
+ # Build a new connection with the server
+ deferred = defer.Deferred()
+ self._reactor.connectTCP(addr[0], addr[1], self.factory)
+ self.pending.append((deferred, message.queries, timeout))
+ return deferred.addCallback(self.filterAnswers)
+ # Don't use this call as it will establish the connection with
another server,
+ # which is more than likely not able to process the request.
+ # TODO If here, it is probably a truncated message got from TCP!
+ return self.queryTCP(message.queries,
timeout).addCallback(self.filterAnswers)
if message.rCode != dns.OK:
return
failure.Failure(self.exceptionForCode(message.rCode)(message))
return (message.answers, message.authority, message.additional)
--- twisted-14.0.2.orig/twisted/names/test/test_rootresolve.py
+++ twisted-14.0.2/twisted/names/test/test_rootresolve.py
@@ -119,6 +119,10 @@ class MemoryDatagramTransport(object):
"""
pass
+ @property
+ def maxPacketSize(self):
+ return self._maxPacketSize
+
verifyClass(IUDPTransport, MemoryDatagramTransport)
--- twisted-14.0.2.orig/twisted/names/test/test_client.py
+++ twisted-14.0.2/twisted/names/test/test_client.py
@@ -1059,7 +1059,7 @@ class FilterAnswersTests(unittest.TestCa
m = dns.Message(trunc=True)
m.addQuery(b'example.com')
- def queryTCP(queries):
+ def queryTCP(queries, timeout = 10):
self.assertEqual(queries, m.queries)
response = dns.Message()
response.answers = ['answer']
--- twisted-14.0.2.orig/twisted/test/proto_helpers.py
+++ twisted-14.0.2/twisted/test/proto_helpers.py
@@ -100,10 +100,14 @@ class FakeDatagramTransport:
def __init__(self):
self.written = []
+ self._maxPacketSize = 512
def write(self, packet, addr=noAddr):
self.written.append((packet, addr))
+ @property
+ def maxPacketSize(self):
+ return self._maxPacketSize
@implementer(ITransport, IConsumer, IPushProducer)
=== PATCH ENDS HERE
-- System Information:
Debian Release: jessie/sid
APT prefers testing-updates
APT policy: (500, 'testing-updates'), (500, 'testing')
Architecture: amd64 (x86_64)
Kernel: Linux 3.14-1-amd64 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages python-twisted-names depends on:
ii python 2.7.8-1
ii python-twisted-core 14.0.2-2
python-twisted-names recommends no packages.
python-twisted-names suggests no packages.
-- no debconf information
--- End Message ---
--- Begin Message ---
Hello Philippe,
while cleaning up a bit the issue queue for twisted based packages I
noticed that this report isn't valid any more.
The package the report was written against isn't created and shipped for
some longer time.
Thus it makes no sense to keep this report open.
Sorry for this issue couldn't be fixed within some Debian packaging
work.
Regards
Carsten
Am Tue, Oct 14, 2014 at 11:26:52AM +0000 schrieb Goetz, Philippe:
> Package: python-twisted-names
> Version: 14.0.2-2
> Severity: grave
> Tags: patch
> Justification: renders package unusable
>
> Dear Maintainers,
>
> Upstream bug: http://twistedmatrix.com/trac/ticket/6949
>
> When using twisted.names.client to request a large number of DNS-SD records,
> whose answer exceeds the UDP limit (512B), the message has to be remade using
> TCP. This makes twisted.names useless for this use and many others cases as
> soon as the response is too large.
>
> I already proposed a patch June 13th, 2014 (4 months ago), without reaction
> since now.
>
> === PATCH STARTS HERE
> Description: twisted.names.server never truncates datagram responses #6949
> Upstream bug: http://twistedmatrix.com/trac/ticket/6949
> .
> Until it supports wiki:EDNS0, twisted.names.server ought to limit the size of
> its response messages to 512B.
> .
> But because of the way dns.Message.decode sets the maxSize=0 and because of
> the
> way server re-uses the request message for its responses, it never actually
> truncates large messages.
> .
> This probably means that some responses will be dropped or fragmented on
> their
> route across the Internet, which means that clients have to wait for a
> timeout
> before re-issuing the query over TCP.
> .
> twisted (14.0.2-2) unstable; urgency=medium
> .
> Author: Philippe Goetz <philippe.go...@siemens.com>
> ---
> Origin: other, <url of original patch>
> Bug: http://twistedmatrix.com/trac/ticket/6949
> Bug-Debian: http://bugs.debian.org/<bugnumber>
> Bug-Ubuntu: https://launchpad.net/bugs/<bugnumber>
> Forwarded: <no|not-needed|url proving that it has been forwarded>
> Reviewed-By: <name and email of someone who approved the patch>
> Last-Update: <YYYY-MM-DD>
>
> --- twisted-14.0.2.orig/twisted/names/dns.py
> +++ twisted-14.0.2/twisted/names/dns.py
> @@ -2738,6 +2738,9 @@ class DNSDatagramProtocol(DNSMixin, prot
> m = Message()
> try:
> m.fromStr(data)
> + m.maxSize = min(512, self.transport.maxPacketSize)
> + if m.trunc:
> + m.trunc = addr # will be used for TCP
> except EOFError:
> log.msg("Truncated packet (%d bytes) from %s" % (len(data),
> addr))
> return
> --- twisted-14.0.2.orig/twisted/names/client.py
> +++ twisted-14.0.2/twisted/names/client.py
> @@ -369,7 +369,24 @@ class Resolver(common.ResolverBase):
> the answers section, the authority section, and the additional
> section.
> """
> if message.trunc:
> - return
> self.queryTCP(message.queries).addCallback(self.filterAnswers)
> + timeout = 10
> + if isinstance(message.trunc, tuple):
> + # Truncated message got from UDP server as trunc is an
> address and not a bool
> + # NOTE: UDP server should be also a TCP server (on the
> address and port) as required by RFCs
> + addr = message.trunc
> + # Try to reuse a connection already established with the
> server
> + for connection in self.connections:
> + if connection.transport.addr == addr:
> + return connection.query(message.queries,
> timeout).addCallback(self.filterAnswers)
> + # Build a new connection with the server
> + deferred = defer.Deferred()
> + self._reactor.connectTCP(addr[0], addr[1], self.factory)
> + self.pending.append((deferred, message.queries, timeout))
> + return deferred.addCallback(self.filterAnswers)
> + # Don't use this call as it will establish the connection with
> another server,
> + # which is more than likely not able to process the request.
> + # TODO If here, it is probably a truncated message got from TCP!
> + return self.queryTCP(message.queries,
> timeout).addCallback(self.filterAnswers)
> if message.rCode != dns.OK:
> return
> failure.Failure(self.exceptionForCode(message.rCode)(message))
> return (message.answers, message.authority, message.additional)
> --- twisted-14.0.2.orig/twisted/names/test/test_rootresolve.py
> +++ twisted-14.0.2/twisted/names/test/test_rootresolve.py
> @@ -119,6 +119,10 @@ class MemoryDatagramTransport(object):
> """
> pass
>
> + @property
> + def maxPacketSize(self):
> + return self._maxPacketSize
> +
>
> verifyClass(IUDPTransport, MemoryDatagramTransport)
>
> --- twisted-14.0.2.orig/twisted/names/test/test_client.py
> +++ twisted-14.0.2/twisted/names/test/test_client.py
> @@ -1059,7 +1059,7 @@ class FilterAnswersTests(unittest.TestCa
> m = dns.Message(trunc=True)
> m.addQuery(b'example.com')
>
> - def queryTCP(queries):
> + def queryTCP(queries, timeout = 10):
> self.assertEqual(queries, m.queries)
> response = dns.Message()
> response.answers = ['answer']
> --- twisted-14.0.2.orig/twisted/test/proto_helpers.py
> +++ twisted-14.0.2/twisted/test/proto_helpers.py
> @@ -100,10 +100,14 @@ class FakeDatagramTransport:
>
> def __init__(self):
> self.written = []
> + self._maxPacketSize = 512
>
> def write(self, packet, addr=noAddr):
> self.written.append((packet, addr))
>
> + @property
> + def maxPacketSize(self):
> + return self._maxPacketSize
>
>
> @implementer(ITransport, IConsumer, IPushProducer)
> === PATCH ENDS HERE
>
>
> -- System Information:
> Debian Release: jessie/sid
> APT prefers testing-updates
> APT policy: (500, 'testing-updates'), (500, 'testing')
> Architecture: amd64 (x86_64)
>
> Kernel: Linux 3.14-1-amd64 (SMP w/1 CPU core)
> Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
> Shell: /bin/sh linked to /bin/dash
>
> Versions of packages python-twisted-names depends on:
> ii python 2.7.8-1
> ii python-twisted-core 14.0.2-2
>
> python-twisted-names recommends no packages.
>
> python-twisted-names suggests no packages.
>
> -- no debconf information
--- End Message ---
_______________________________________________
Python-modules-team mailing list
Python-modules-team@alioth-lists.debian.net
https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/python-modules-team
