bpo-37345: Add formal UDPLITE support by LivInTheLookingGlass · Pull Request #14258 · python/cpython

LivInTheLookingGlass · 2019-06-20T06:37:52Z

At the moment you can definitely use UDPLITE sockets on Linux systems, but it would be good if this support were formalized such that you can detect support at runtime easily.

At the moment, to make and use a UDPLITE socket requires something like the following code:

>>> import socket
>>> a = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, 136)
>>> b = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, 136)
>>> a.bind(('localhost', 44444))
>>> b.sendto(b'test'*256, ('localhost', 44444))
>>> b.setsockopt(136, 10, 16)
>>> b.sendto(b'test'*256, ('localhost', 44444))
>>> b.setsockopt(136, 10, 32)
>>> b.sendto(b'test'*256, ('localhost', 44444))
>>> b.setsockopt(136, 10, 64)
>>> b.sendto(b'test'*256, ('localhost', 44444))

If you look at this through Wireshark, you can see that the packets are different in that the checksums and checksum coverages change.

With the pull request that I am submitting momentarily, you could do the following code instead:

>>> import socket
>>> a = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDPLITE)
>>> b = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDPLITE)
>>> a.bind(('localhost', 44444))
>>> b.sendto(b'test'*256, ('localhost', 44444))
>>> b.set_send_checksum_coverage(16)
>>> b.sendto(b'test'*256, ('localhost', 44444))
>>> b.set_send_checksum_coverage(32)
>>> b.sendto(b'test'*256, ('localhost', 44444))
>>> b.set_send_checksum_coverage(64)
>>> b.sendto(b'test'*256, ('localhost', 44444))

One can also detect support for UDPLITE just by checking

>>> hasattr(socket, 'IPPROTO_UDPLITE')

https://bugs.python.org/issue37345

update

mangrisano

Hi, thank you for the pull request.
I've left a suggestion about the changes.

Thank you :)

asvetlov

Please add NEWS entry: https://devguide.python.org/committing/?highlight=blurb#what-s-new-and-news-entries

bedevere-bot · 2019-06-22T08:30:58Z

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

asvetlov · 2019-06-22T08:37:53Z

  .. versionadded:: 3.8

+- :const:`IPPROTO_UDPLITE` is a variant on UDP which allows you to specify
+  what portion of a packet to cover with the checksum. It adds the methods


Please rephrase.
IPPROTO_UDPLITE doesn't add the methods but allows to use UDPLITE_SEND_CSCOV / UDPLITE_RECV_CSCOV in setsockopt

Does the new version make this better in your eyes?

LivInTheLookingGlass · 2019-06-23T03:31:58Z

I have made the requested changes; please review again.

bedevere-bot · 2019-06-23T03:32:01Z

Thanks for making the requested changes!

@asvetlov: please review the changes made to this pull request.

asvetlov · 2019-06-24T09:59:25Z

Thanks!

At the moment you can definitely use UDPLITE sockets on Linux systems, but it would be good if this support were formalized such that you can detect support at runtime easily. At the moment, to make and use a UDPLITE socket requires something like the following code: ``` >>> import socket >>> a = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, 136) >>> b = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, 136) >>> a.bind(('localhost', 44444)) >>> b.sendto(b'test'*256, ('localhost', 44444)) >>> b.setsockopt(136, 10, 16) >>> b.sendto(b'test'*256, ('localhost', 44444)) >>> b.setsockopt(136, 10, 32) >>> b.sendto(b'test'*256, ('localhost', 44444)) >>> b.setsockopt(136, 10, 64) >>> b.sendto(b'test'*256, ('localhost', 44444)) ``` If you look at this through Wireshark, you can see that the packets are different in that the checksums and checksum coverages change. With the pull request that I am submitting momentarily, you could do the following code instead: ``` >>> import socket >>> a = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDPLITE) >>> b = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDPLITE) >>> a.bind(('localhost', 44444)) >>> b.sendto(b'test'*256, ('localhost', 44444)) >>> b.set_send_checksum_coverage(16) >>> b.sendto(b'test'*256, ('localhost', 44444)) >>> b.set_send_checksum_coverage(32) >>> b.sendto(b'test'*256, ('localhost', 44444)) >>> b.set_send_checksum_coverage(64) >>> b.sendto(b'test'*256, ('localhost', 44444)) ``` One can also detect support for UDPLITE just by checking ``` >>> hasattr(socket, 'IPPROTO_UDPLITE') ``` https://bugs.python.org/issue37345

LivInTheLookingGlass added 7 commits June 19, 2019 22:21

Merge pull request #1 from python/master

4dae4b3

update

Add formal support for UDPLITE sockets

8b7ec58

Copy UDP tests to UDPLITE

3e6763d

Make tests skip if UDPLITE support not present

5c218dc

Add documentation

260489b

Ensure that helper macros are defined

8f14db6

Correct typo (missing quotes)

7c799b5

the-knights-who-say-ni added the CLA signed label Jun 20, 2019

bedevere-bot added the awaiting review label Jun 20, 2019

mangrisano suggested changes Jun 20, 2019

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Comment thread Doc/library/socket.rst Outdated

bedevere-bot added awaiting core review and removed awaiting review labels Jun 20, 2019

brettcannon added the type-feature A feature request or enhancement label Jun 21, 2019

LivInTheLookingGlass added 3 commits June 21, 2019 20:27

Remove helper methods as requested

edef62e

Correct availability/added

16fe13b

Add documentation about how to change checksum coverage

9c4b602

asvetlov requested changes Jun 22, 2019

View reviewed changes

Comment thread Modules/socketmodule.c

bedevere-bot added awaiting changes and removed awaiting core review labels Jun 22, 2019

asvetlov reviewed Jun 22, 2019

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Comment thread Doc/library/socket.rst Outdated

asvetlov reviewed Jun 22, 2019

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Comment thread Doc/library/socket.rst Outdated

asvetlov reviewed Jun 22, 2019

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LivInTheLookingGlass and others added 4 commits June 22, 2019 08:38

Make docs edits requested by core contributor

5bfb271

Add news page and update availability

fe02208

Correct roll in news

8c5ebba

Update 2019-06-22-08-51-44.bpo-37345.o8XABX.rst

828c486

bedevere-bot added awaiting change review and removed awaiting changes labels Jun 23, 2019

asvetlov approved these changes Jun 24, 2019

View reviewed changes

bedevere-bot added awaiting merge and removed awaiting change review labels Jun 24, 2019

asvetlov added the 🤖 automerge label Jun 24, 2019

miss-islington merged commit 2ac3bab into python:master Jun 24, 2019

bedevere-bot removed the awaiting merge label Jun 24, 2019

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bpo-37345: Add formal UDPLITE support - #14258

bpo-37345: Add formal UDPLITE support#14258
miss-islington merged 14 commits into
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