I want to process the ICMP error and implement UDP PMTU discovery, so I
have to call recvmsg with MSG_ERRQUEUE
It has been 4 years, any reasonable solutions for this problem??
在 2013年2月28日星期四 UTC+8下午9:31:54，Robert写道：
>
> +cc golang-dev
> +bcc golang-nuts
>
> Hello,
>
> I would like to propose a change in the net package in the
> {Read,Write}Msg* methods (they are to be new in Go1.1), so that they
> allow flags to be passed in. As far as I know, the only way to read a
> socket's error queue in Linux is to use recvmsg with MSG_ERRQUEUE flag
> set. The {Read,Write}Msg methods don't allow flags to be passed in and
> set them always to 0.
>
> I propose that both ReadMsg* and WriteMsg* take an additional argument
> for flags. This obviously exports system-specific flags out of the net
> package, but we already do that in the other direction in these same
> methods. ReadMsg should filter out MSG_WAITALL (because it seems
> nonsensical or poorly defined for nonblocking operations); all other
> flags from POSIX and Linux-specific ones seem not to interfere with
> the assumptions related to the poll server or nonblocking behaviour. I
> also propose that ReadMsgUnix set MSG_CMSG_CLOEXEC, for similar
> reasons we set O_CLOEXEC in open() (although I'm not sure if that
> shouldn't be the domain of someone who actually uses SCM_RIGHTS). For
> WriteMsg* I didn't find any flags that would seem to interfere with
> assumptions related to the poll server and nonblocking behaviour.
>
> I will send a CL upon request; I didn't do it first because the
> contributing guidelines strongly advise against that. This is a change
> that, as far as I understand the backwards compatibility guarantees,
> should be made before Go1.1 or not at all in the foreseeable future.
>
> Robert
>
> On Thu, Feb 28, 2013 at 2:58 AM, Mikio Hara <[email protected]
> <javascript:>> wrote:
> >> Would adding a way to call ReadMsg with flags be reasonable?
> >
> > And WriteMsg too? Not sure, but Read/WriteMsgIP, UDP methods
> > are new API for Go 1.1. I think you can contribute a bugfix patch
> > until Go 1.1 cutoff if you think that's an API design bug.
>
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