From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] net: packet: option to only pass skb protocol Date: Tue, 5 Jan 2010 23:45:24 +0200 Message-ID: <20100105214524.GA31301@redhat.com> References: <20100105185732.GA30346@redhat.com> <4B43AEF6.6050701@nortel.com> <20100105.134218.258781374.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: cfriesen@nortel.com, eric.dumazet@gmail.com, nhorman@tuxdriver.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: David Miller Return-path: Content-Disposition: inline In-Reply-To: <20100105.134218.258781374.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Jan 05, 2010 at 01:42:18PM -0800, David Miller wrote: > From: "Chris Friesen" > Date: Tue, 05 Jan 2010 15:28:22 -0600 > > > On 01/05/2010 12:57 PM, Michael S. Tsirkin wrote: > >> When sending packets with a packet socket it is often necessary to set > >> protocol in msg_name: otherwise the protocol field in the skb will not > >> be set correctly. > > > > What about automatically detecting the protocol from the data being sent > > to avoid the necessity of specifying it in the first place? > > This limits packet socket usage to only protocols the kernel is aware > of, defeating part of the usefulness of the packet socket facility. We could do this if the protocol is ETH_P_ALL - skbs end up with this protocol currently when sendmsg does not have msgname and when socket is set up to listen for all packets. It's not a valid protocol value, is it? -- MST