From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Dunlap Subject: Re: [PATCH] Phonet: improve documentation Date: Wed, 24 Sep 2008 08:45:48 -0700 Message-ID: <48DA60AC.5030903@oracle.com> References: <200809221845.54736.remi.denis-courmont@nokia.com> <1222098445-26175-11-git-send-email-remi.denis-courmont@nokia.com> <20080923144320.fc1fc81c.randy.dunlap@oracle.com> <200809241515.06378.remi.denis-courmont@nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Miller , netdev@vger.kernel.org To: =?ISO-8859-1?Q?R=E9mi_Denis-Courmont?= Return-path: Received: from rgminet01.oracle.com ([148.87.113.118]:12716 "EHLO rgminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751437AbYIXPq1 (ORCPT ); Wed, 24 Sep 2008 11:46:27 -0400 In-Reply-To: <200809241515.06378.remi.denis-courmont@nokia.com> Sender: netdev-owner@vger.kernel.org List-ID: R=E9mi Denis-Courmont wrote: > Fix grammar errors spotted by Randy Dunlap, > and adds some more details. Um, let me try again, please. > Signed-off-by: Remi Denis-Courmont > --- > Documentation/networking/phonet.txt | 32 +++++++++++++++++++++----= ------- > 1 files changed, 21 insertions(+), 11 deletions(-) >=20 > diff --git a/Documentation/networking/phonet.txt b/Documentation/netw= orking/phonet.txt > index f3c72e0..1506c31 100644 > --- a/Documentation/networking/phonet.txt > +++ b/Documentation/networking/phonet.txt > @@ -21,7 +21,7 @@ depending on the device, such as: > Packets format > -------------- > =20 > -Phonet packet have a common header as follow: > +Phonet packets have a common header as follow: follows: > =20 > 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 */ > }; > =20 > -The device ID is split: the 6 higher order bits consitutes the devic= e > -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 belo= w). > +The next 7 bytes are part of the network-layer header. > + > +The device ID is split: the 6 higher order-bits consitute the device higher-order bits > +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). > =20 > -The modem always has address number zero. Each other device has a it= s > -own 6-bits address. > +The modem always has address number zero. All other device have a th= eir > +own 6-bit address. > =20 > =20 > 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 onl= y > -send and receive Phonet packets. > +perspective. Each Phonet network device shall prepend and set the me= dia > +type byte as appropriate. For convenience, a common phonet_header_op= s > +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 packe= ts > +type (ETH_P_PHONET) which is out of the Ethernet type range. They ca= n > +only send and receive Phonet packets. > + > +The virtual TUN tunnel device driver can also be used for Phonet. Th= is > +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= =2E > =20 > Note that Phonet interfaces are not allowed to re-order packets, so > only the (default) Linux FIFO qdisc should be used with them. Thanks, ~Randy