From owner-svn-src-head@freebsd.org  Sat Aug 20 17:30:56 2016
Return-Path: <owner-svn-src-head@freebsd.org>
Delivered-To: svn-src-head@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 46120BC0857;
 Sat, 20 Aug 2016 17:30:56 +0000 (UTC) (envelope-from slw@zxy.spb.ru)
Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 043821F0B;
 Sat, 20 Aug 2016 17:30:56 +0000 (UTC) (envelope-from slw@zxy.spb.ru)
Received: from slw by zxy.spb.ru with local (Exim 4.86 (FreeBSD))
 (envelope-from <slw@zxy.spb.ru>)
 id 1bbA6c-0004bP-UR; Sat, 20 Aug 2016 20:30:50 +0300
Date: Sat, 20 Aug 2016 20:30:50 +0300
From: Slawa Olhovchenkov <slw@zxy.spb.ru>
To: Ryan Stone <rysto32@gmail.com>
Cc: Bruce Simpson <bms@fastmail.net>,
 "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>,
 Ryan Stone <rstone@freebsd.org>,
 "src-committers@freebsd.org" <src-committers@freebsd.org>,
 "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>,
 Adrian Chadd <adrian@freebsd.org>
Subject: Re: svn commit: r304436 - in head: . sys/netinet
Message-ID: <20160820173050.GQ22212@zxy.spb.ru>
References: <201608182259.u7IMx5oW002018@repo.freebsd.org>
 <4fbc2e1d-3a62-5963-83d5-f9c931503e51@fastmail.net>
 <3806700d-ed27-7915-4818-c2d64f7b806d@fastmail.net>
 <CAFMmRNyi=PwE9pc9_8wCU63=HttUzFR4Zh2v=uHKcQ-zaLxdJQ@mail.gmail.com>
 <fcb33eac-ec99-03c7-57b5-f24f86c4f41a@fastmail.net>
 <CAFMmRNwDPy4Hd35DrfREZQzjvd89qw=zhEriddG8U8NV7tD=EA@mail.gmail.com>
 <6f4449f2-d145-8b49-c3f0-433e8ff4d2a2@fastmail.net>
 <CAFMmRNypgJc00XH277oB3EEGje4xq+8_qcJfZu4jjBfTfa7GGQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAFMmRNypgJc00XH277oB3EEGje4xq+8_qcJfZu4jjBfTfa7GGQ@mail.gmail.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
X-SA-Exim-Connect-IP: <locally generated>
X-SA-Exim-Mail-From: slw@zxy.spb.ru
X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 20 Aug 2016 17:30:56 -0000

On Sat, Aug 20, 2016 at 12:36:58PM -0400, Ryan Stone wrote:

> + adrian@, who prompted me to look at UDP in the first place
> 
> 
> I'm really not sure what my next step should be.  I'm willing to revert
> r304436, but I really don't want to revert r304437 because we've seen
> crashes in the real world due to the missing locking.  Unfortunately,
> reverting r304436 would mean that every UDP packet would incur the overhead
> of an additional rlock/runlock call, which is what I've been trying to
> avoid.  I don't see a particularly good path forward.

As I understund specific handling of broadcast required only for
routers (by RFC1812).
For host enought have [hidden] alias with broadcsts bits.
Anyway, don't should relay on the L2 information, you can recive L3
unicast addressed packets (with alien dst IP address) in L2 broadcas
packet.

Sorry if I am miss something in you discurs.