From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <ammarfaizi2@gnuweeb.org>
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
	server-vie001.gnuweeb.org
X-Spam-Level: 
X-Spam-Status: No, score=-1.2 required=5.0 tests=ALL_TRUSTED,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,URIBL_DBL_BLOCKED_OPENDNS,
	URIBL_ZEN_BLOCKED_OPENDNS autolearn=ham autolearn_force=no
	version=3.4.6
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org;
	s=new2025; t=1754014784;
	bh=pmMHnWcFByI95Hg0XCH82eXSTdESjdaUArijN/MjuGE=;
	h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version:
	 Content-Type:In-Reply-To:Message-ID:Date:From:Reply-To:Subject:To:
	 Cc:In-Reply-To:References:Resent-Date:Resent-From:Resent-To:
	 Resent-Cc:User-Agent:Content-Type:Content-Transfer-Encoding;
	b=S5oVj0tbYiOUPicpKzNPUW02VWiRFofnXrVuwcjjfka+Hwztlar0P4xBO/QQT4Z+f
	 x6FfX8g64U5b89lmrzmWz61Hsd41BB5UdFAsyb9AYDYS9IuMljBdCOwtRYh/xXtwTq
	 qj3wngiHD1YGNMzPcsNgw/9sIJOcroHdn5mLIduhy3obXixyEPHHWqQzucVNHd0yIz
	 /ZIzgHWs82dWiHkCqOUQIZW9QPqgrmDOf/0+mn5CClrMsacq/n9rNBDdaYs8095XaG
	 Sd18bNf6yYPuHFuBz+Fyx0QEVoC9g5hZAIp6fpk9VBLrafqk/dRyL4T373N3la0N7B
	 MkXXRAY+EbObw==
Received: from biznet-home.integral.gnuweeb.org (unknown [182.253.126.229])
	by server-vie001.gnuweeb.org (Postfix) with ESMTPSA id 61A7F3126F06;
	Fri,  1 Aug 2025 02:19:43 +0000 (UTC)
Date: Fri, 1 Aug 2025 11:19:39 +0900
From: Ammar Faizi <ammarfaizi2@gnuweeb.org>
To: Ahmad Gani <reyuki@gnuweeb.org>
Cc: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>,
	GNU/Weeb Mailing List <gwml@vger.gnuweeb.org>
Subject: Re: [PATCH gwproxy v1 0/3] Initial work for DNS lookup implementation
Message-ID: <aIwkO9Aw+IFht0vd@biznet-home.integral.gnuweeb.org>
References: <20250731030856.366368-1-reyuki@gnuweeb.org>
 <aItyGEFcXFieqp+r@linux.gnuweeb.org>
 <CAADvAgonYwm-mwHB-zC_MOb5gYWvd=eH2KeZ7h6WTSF0Tgud0A@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAADvAgonYwm-mwHB-zC_MOb5gYWvd=eH2KeZ7h6WTSF0Tgud0A@mail.gmail.com>
List-Id: <gwml.vger.gnuweeb.org>

On Fri, Aug 01, 2025 at 08:49:22AM +0700, reyuki wrote:
> I think I get the general idea of using pollable socket:
> - mark the UDP socket as non block
> - let the caller have reference to the socket, so they can poll it
> 
> But have difficulties in the technical implementation:
> 
> When the caller is notified, they must call what?

The same thing as other sockets. If you get EPOLLIN, that means there
is data to recv, so call recv/recvfrom.

> It is a UDP socket, it's said to be stateless, does connect can possibly
> return EINPROGRESS? It seems to be a common case in non-blocking

Most likely not. That will only set the dst addr. Apart from that, a
connect() call is optional if you use a UDP socket as a client.

sendto(2) and recvfrom(2) can be used if you ever want to use one
SOCK_DGRAM with multiple dst addresses.

> TCP socket. And if EAGAIN is received from recv, do we retry from send?

No, -EAGAIN from recv simply means the socket is non-blocking and there
is no data to be read at the moment.

> I find it unclear how the library and the program interact when using the
> non-blocking behavior, but I think I will give it a thought (maybe add an
> internal state to address these concerns).

The socks5 lib can do that. Why the DNS lib not?

> I can't view the linked message from the given link, is it a private community?

Oh, I didn't know if it was private. It seems the admins recently made
it private. I remember the days when it was public. But I have quoted
the needed sentences, I suppose that's enough.

-- 
Ammar Faizi