From patchwork Wed Sep 24 16:11:39 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?R=C3=A9mi_Denis-Courmont?= X-Patchwork-Id: 1297 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id A7989DDFCD for ; Thu, 25 Sep 2008 02:12:10 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752040AbYIXQME (ORCPT ); Wed, 24 Sep 2008 12:12:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750988AbYIXQME (ORCPT ); Wed, 24 Sep 2008 12:12:04 -0400 Received: from smtp.nokia.com ([192.100.122.233]:17739 "EHLO mgw-mx06.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751996AbYIXQL7 (ORCPT ); Wed, 24 Sep 2008 12:11:59 -0400 Received: from esebh107.NOE.Nokia.com (esebh107.ntc.nokia.com [172.21.143.143]) by mgw-mx06.nokia.com (Switch-3.2.6/Switch-3.2.6) with ESMTP id m8OGBtEc025585 for ; Wed, 24 Sep 2008 19:11:57 +0300 Received: from vaebh102.NOE.Nokia.com ([10.160.244.23]) by esebh107.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.3959); Wed, 24 Sep 2008 19:11:54 +0300 Received: from vaebh101.NOE.Nokia.com ([10.160.244.22]) by vaebh102.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.3959); Wed, 24 Sep 2008 19:11:54 +0300 Received: from localhost.localdomain ([172.21.41.62]) by vaebh101.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.3959); Wed, 24 Sep 2008 19:11:52 +0300 From: Remi Denis-Courmont To: netdev@vger.kernel.org Cc: =?utf-8?q?R=C3=A9mi=20Denis-Courmont?= Subject: [PATCH 2/3] Phonet: improve documentation Date: Wed, 24 Sep 2008 19:11:39 +0300 Message-Id: <1222272700-28232-2-git-send-email-remi.denis-courmont@nokia.com> X-Mailer: git-send-email 1.5.4.3 In-Reply-To: <> References: <> MIME-Version: 1.0 X-OriginalArrivalTime: 24 Sep 2008 16:11:54.0208 (UTC) FILETIME=[42BBFE00:01C91E60] X-Nokia-AV: Clean Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Rémi Denis-Courmont Fix grammar errors spotted by Randy Dunlap, and adds some more details. Signed-off-by: Remi Denis-Courmont --- Documentation/networking/phonet.txt | 32 +++++++++++++++++++++----------- 1 files changed, 21 insertions(+), 11 deletions(-) diff --git a/Documentation/networking/phonet.txt b/Documentation/networking/phonet.txt index f3c72e0..57d3e59 100644 --- a/Documentation/networking/phonet.txt +++ b/Documentation/networking/phonet.txt @@ -21,7 +21,7 @@ depending on the device, such as: Packets format -------------- -Phonet packet have a common header as follow: +Phonet packets have a common header as follows: struct phonethdr { uint8_t pn_media; /* Media type (link-layer identifier) */ @@ -33,14 +33,17 @@ Phonet packet have a common header as follow: uint8_t pn_sobj; /* Sender object ID */ }; -The device ID is split: the 6 higher order bits consitutes the device -address, while the 2 lower order bits are used for multiplexing, as are -the 8-bits object identifiers. As such, Phonet can be considered as a +On Linux, the link-layer header includes the pn_media byte (see below). +The next 7 bytes are part of the network-layer header. + +The device ID is split: the 6 higher-order bits consitute the device +address, while the 2 lower-order bits are used for multiplexing, as are +the 8-bit object identifiers. As such, Phonet can be considered as a network layer with 6 bits of address space and 10 bits for transport protocol (much like port numbers in IP world). -The modem always has address number zero. Each other device has a its -own 6-bits address. +The modem always has address number zero. All other device have a their +own 6-bit address. Link layer @@ -49,11 +52,18 @@ Link layer Phonet links are always point-to-point links. The link layer header consists of a single Phonet media type byte. It uniquely identifies the link through which the packet is transmitted, from the modem's -perspective. - -Linux Phonet network interfaces use a dedicated link layer type -(ETH_P_PHONET) which is out of the Ethernet type range. They can only -send and receive Phonet packets. +perspective. Each Phonet network device shall prepend and set the media +type byte as appropriate. For convenience, a common phonet_header_ops +link-layer header operations structure is provided. It sets the +media type according to the network device hardware address. + +Linux Phonet network interfaces support a dedicated link layer packets +type (ETH_P_PHONET) which is out of the Ethernet type range. They can +only send and receive Phonet packets. + +The virtual TUN tunnel device driver can also be used for Phonet. This +requires IFF_TUN mode, _without_ the IFF_NO_PI flag. In this case, +there is no link-layer header, so there is no Phonet media type byte. Note that Phonet interfaces are not allowed to re-order packets, so only the (default) Linux FIFO qdisc should be used with them.