code review 10089046: go.net/ipv6: add deadline methods to PacketConn

go.net/ipv6: add deadline methods to PacketConn

Update issue 5538

[mikio, 2013-06-07 06:11:22]

Hello dave@cheney.net (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go.net

[dave_cheney.net, 2013-06-07 11:02:51]

On 2013/06/07 06:11:22, mikio wrote:
> Hello mailto:dave@cheney.net (cc: mailto:golang-dev@googlegroups.com),
> 
> I'd like you to review this change to
> https://code.google.com/p/go.net

This looks reasonable. I have two small questions.

1. Is it possible to achieve this by embedding ?

2. Why are you adding these methods ? For completeness, or so ipv6.PacketConn
implements net.Conn ?

[mikio, 2013-06-07 13:51:51]

PTAL

On Fri, Jun 7, 2013 at 8:02 PM,  <dave@cheney.net> wrote:

> 1. Is it possible to achieve this by embedding ?

What do you mean by embedding?

> 2. Why are you adding these methods ?

Deadline would be help to make a small simple tool like network
loopback or linktrace stuff w/o having read/write message pump-
like stuff.

> For completeness, or so
> ipv6.PacketConn implements net.Conn ?

What you are saying is that, ah, sorry but I don't understand.
ipv6.PacketConn implements net.PacketConn?

[r, 2013-06-07 15:32:41]

I may have the wrong package, but I believe Brad asked, reasonably, to
see a description of your plans for this work. I'm very happy to see
your contributions but it's more comfortable to have a road map in
place.

If you sent one and I missed it, I apologize; the recent mail flood
has reached the tip of Mount Ararat.

-rob

[mikio, 2013-06-08 04:44:36]

On Sat, Jun 8, 2013 at 12:32 AM, Rob Pike <r@golang.org> wrote:

> I may have the wrong package, but I believe Brad asked, reasonably, to
> see a description of your plans for this work. I'm very happy to see
> your contributions but it's more comfortable to have a road map in
> place.

Sure, thank you for the notice and sorry for my laziness.
I forget to answer to his request (because of my laziness).

For stdlib, I now have no concrete plan except issue 5199.

For others in sub repositories, issue 5538 and 5539 are the plan.

All patches are just for adding basic network facility control as described in
on-line manual netintro; addressing and protocol API is already provided by
stdlib, so the rest would be routing and its helpers; go.net/ipv4, go.net/ipv6
and go.net/route. Almost all look boring bolierplates but once we have server
stuff in go on distributed environment, then (I guess) we will also need some
stuff that interfaces with infrastructures.

This CL is part of issue 5538. The API is similar to go.net/ipv4; providing
control knobs, toggles and its bearers ReadFrom, WriteTo methods.

[dave_cheney.net, 2013-06-10 01:19:15]

On 2013/06/07 13:51:51, mikio wrote:
> PTAL
> 
> On Fri, Jun 7, 2013 at 8:02 PM,  <mailto:dave@cheney.net> wrote:
> 
> > 1. Is it possible to achieve this by embedding ?
> 
> What do you mean by embedding?

Struct embedding. Currently you have to manually forward these methods to
c.payloadHandler because there are probably several structs embedded in
ipv6.PacketConn that have Set*DeadLine methods. I wonder if it were possible to
rearrange things so these forwarding methods could be made unnecessary. 

> 
> > 2. Why are you adding these methods ?
> 
> Deadline would be help to make a small simple tool like network
> loopback or linktrace stuff w/o having read/write message pump-
> like stuff.

SGTM.

> 
> > For completeness, or so
> > ipv6.PacketConn implements net.Conn ?
> 
> What you are saying is that, ah, sorry but I don't understand.
> ipv6.PacketConn implements net.PacketConn?

ipv6.PacketConn probably aims to implement both net.Conn and net.PacketConn, the
Deadline methods are necessary for the former, an ReadFrom / WriteTo for the
latter.

[dave_cheney.net, 2013-06-11 11:08:54]

LGTM. I've had a play with this and cannot see a straight forward way to setup
the embedding. If the goal is for *ipv6.PacketConn to implement net.Conn or
net.PacketConn, please add a small test, something like

var _ net.Conn = new(PacketConn)
var _ net.PacketConn = new(PacketConn)

If this is not your intention, please disregard this suggestion.

[mikio, 2013-06-15 02:48:48]

> If the goal is for *ipv6.PacketConn to implement net.Conn or
> net.PacketConn,

I dropped both Read and Write methods from go.net/ipv4 a few months ago
because almost apps that need this raw API are pretty binary wire-format 
datagram protocols, and seems like there's no point to do that.

[dave_cheney.net, 2013-06-15 02:50:49]

On 2013/06/15 02:48:48, mikio wrote:
> > If the goal is for *ipv6.PacketConn to implement net.Conn or
> > net.PacketConn,
> 
> I dropped both Read and Write methods from go.net/ipv4 a few months ago
> because almost apps that need this raw API are pretty binary wire-format 
> datagram protocols, and seems like there's no point to do that.

Cool. LGTM.

[mikio, 2013-06-15 04:05:42]

*** Submitted as
https://code.google.com/p/go/source/detail?r=8f3271ed32ca&repo=net ***

go.net/ipv6: add deadline methods to PacketConn

Update issue 5538

R=dave, r
CC=golang-dev
https://codereview.appspot.com/10089046