neterror

Documentation

Overview

Package neterror classifies network errors.

Index

• func PacketWasTruncated(err error) bool
• func TreatAsLostUDP(err error) bool

Functions

func PacketWasTruncated

func PacketWasTruncated(err error) bool

PacketWasTruncated reports whether err indicates truncation but the RecvFrom that generated err was otherwise successful. On Windows, Go's UDP RecvFrom calls WSARecvFrom which returns the WSAEMSGSIZE error code when the received datagram is larger than the provided buffer. When that happens, both a valid size and an error are returned (as per the partial fix for golang/go#14074). If the WSAEMSGSIZE error is returned, then we ignore the error to get semantics similar to the POSIX operating systems. One caveat is that it appears that the source address is not returned when WSAEMSGSIZE occurs, but we do not currently look at the source address.

func TreatAsLostUDP

func TreatAsLostUDP(err error) bool

TreatAsLostUDP reports whether err is an error from a UDP send operation that should be treated as a UDP packet that just got lost.

Notably, on Linux this reports true for EPERM errors (from outbound firewall blocks) which aren't really send errors; they're just sends that are never going to make it because the local OS blocked it.