From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kalle Valo Subject: Re: [PATCH] net: arp, ipv6: handle special case of tap device Date: Thu, 04 Oct 2018 12:53:46 +0300 Message-ID: <87muru2g2d.fsf@codeaurora.org> References: <20180926093018.6646-1-vdronov@redhat.com> <20180929.114023.1370133506922372520.davem@davemloft.net> <1615981257.17285278.1538393552487.JavaMail.zimbra@redhat.com> <20181002.222540.1948082296309410659.davem@davemloft.net> <2058134821.17788321.1538573112620.JavaMail.zimbra@redhat.com> Mime-Version: 1.0 Content-Type: text/plain Cc: David Miller , kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org, syzkaller@googlegroups.com, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org To: Vladis Dronov Return-path: In-Reply-To: <2058134821.17788321.1538573112620.JavaMail.zimbra@redhat.com> (Vladis Dronov's message of "Wed, 3 Oct 2018 09:25:12 -0400 (EDT)") Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Vladis Dronov writes: >> From: "David Miller" >> Sent: Wednesday, October 3, 2018 7:25:40 AM >> >> > Probably, this functionality is already used by some userspace, so I >> > believe, I cannot just remove TUNSETLINK ioctl. >> >> Who uses it, how do they use it, and what do they sanely expect about >> the link layer header properties of a tap device which has had ->type >> changed? > > Honestly, I have no idea. I was working on a syzkaller bug report and > found that the reason for that bug was TUNSETLINK ioctl. > > This ioctl was introduced 13 years ago with ff4cc3ac93e1d and it says: > >> For use with >> wireless and other networking types it should be possible to set the >> ARP type via an ioctl. > > , that's all. Let me try to prepare a patch that sets dev->addr_len and > dev->broadcast according to dev->type. I would probably need an advise > what other fields must be adjusted too. > > Otherwise, we can just to remove the TUNSETLINK ioctl. Let's add linux-wireless in case someone there knows about the ioctl. -- Kalle Valo