MagicStack / MagicStack/uvloop

getaddrinfo() returns wrong scope ID for IPv6 link-local addresses when type=SocketKind.SOCK_STREAM

Open
#539 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
Cython
Stars
11.9k
Forks
616
PR merge metrics
No merged PRs in 30d

Description

* **uvloop version**: 0.17.0
* **Python version**: 3.11.3
* **Platform**: Linux
* **Can you reproduce the bug with `PYTHONASYNCIODEBUG` in env?**: yes
* **Does uvloop behave differently from vanilla asyncio? How?**: Vanilla asyncio returns the correct scope ID, uvloop returns 0

When passing `type=SocketKind.SOCK_STREAM` to `getaddrinfo()` in uvloop, the scope ID for link-local addresses is left as 0. This works correctly (returns nonzero scope ID) in `socket.getaddrinfo()` and vanilla asyncio's corresponding function.

Repro script (requires `psutil` installed):
```python
from asyncio import get_running_loop, run
from socket import SocketKind

import psutil
import uvloop

async def main():
for ifname, addresses in psutil.net_if_addrs().items():
for addr in addresses:
if addr.address.startswith("fe80::") and "%" in addr.address:
gai_res = await get_running_loop().getaddrinfo(addr.address, 0, type=SocketKind.SOCK_STREAM)
scope_id = gai_res[-1][-1][-1]
print("Scope id for", gai_res[-1], "is", scope_id)
return

print("Could not find a suitable link-local address")

# Comment out this line, and it works fine
uvloop.install()
run(main())
```

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the provided reproduction script on Linux with a link-local IPv6 address, comparing uvloop with vanilla asyncio and socket.getaddrinfo(). The issue is done when uvloop returns the correct nonzero scope ID for SOCK_STREAM, matching the other implementations.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
networking
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.