internal/socket: use interface not type assertions to infer a wrapped net.Conn's kind

When passing a wrapped connection to ipv{4,6}.NewPacketConn, calls to
ReadBatch will fail with an invalid connection error. This is because
NewConn performs a type assertion to determine the type (TCP, UDP, IP)
of the net.Conn.
In order to allow for wrapped connections to be passed to NewConn, we
can use an interface assertion that checks for methods on the net.Conn
that are unique to TCP, UDP and IP.

Fixes golang/go#42444.

Change-Id: I07cdb037829643f5cf4cd77105a772fcff8c4b2a
Reviewed-by: Emmanuel Odeke <>
Reviewed-by: Ian Lance Taylor <>
Run-TryBot: Emmanuel Odeke <>
TryBot-Result: Go Bot <>
Trust: Daniel Martí <>
2 files changed
tree: fa702c3b2244679b57629b620cc774198ec32efe
  1. bpf/
  2. context/
  3. dict/
  4. dns/
  5. html/
  6. http/
  7. http2/
  8. icmp/
  9. idna/
  10. internal/
  11. ipv4/
  12. ipv6/
  13. lif/
  14. nettest/
  15. netutil/
  16. proxy/
  17. publicsuffix/
  18. route/
  19. trace/
  20. webdav/
  21. websocket/
  22. xsrftoken/
  23. .gitattributes
  24. .gitignore
  26. codereview.cfg
  29. go.mod
  30. go.sum

Go Networking

Go Reference

This repository holds supplementary Go networking libraries.


The easiest way to install is to run go get -u You can also manually git clone the repository to $GOPATH/src/

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