From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roberto Riggio Subject: Re: Fields alignment when extended mask is present Date: Mon, 21 Feb 2011 10:47:49 +0100 Message-ID: <4D6234C5.2020201@create-net.org> References: <4D60F317.8090007@create-net.org> <1298280460.3707.1.camel@jlt3.sipsolutions.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1298280460.3707.1.camel-8upI4CBIZJIJvtFkdXX2HixXY32XiHfO@public.gmane.org> Sender: radiotap-owner-sUITvd46vNxg9hUCZPvPmw@public.gmane.org To: Johannes Berg Cc: radiotap-qavaossjCcEdnm+yROfE0A@public.gmane.org List-Id: radiotap@radiotap.org Il 21/02/2011 10:27, Johannes Berg ha scritto: > On Sun, 2011-02-20 at 11:55 +0100, Roberto Riggio wrote: >> Hi, >> >> I'm generating a radio tap header with extended mask in order to >> specify a multi rate retry chain. In the first mask i have 4 fields >> each of them 8 bits long, so no padding problem. >> >> In the second, third and forth mask I have only the rate and the retries >> fields should I use padding between one mask and the next: >> >> rate_1 (8) >> retry_1 (8) >> pad (8) >> pad (8) >> rate_2 (8) >> retry_2 (8) >> pad (8) >> pad (8) >> >> or insted: >> >> rate_1 (8) >> retry _1 (8) >> rate_2 (8) >> retry _2 (8) > What's with the "(8)"? Generally, anything in the data portion of > radiotap needs to be padded to the right position. (8) was the field length. in the example above i;ve repoted two different radiotap headers where i specify twice the rate and the retries field. of course i know that in this case i will have to put to it-present bitmasks and i will have to set the bit 31 of the first bitmask to 1. what i'm not sure is if i have to pad the first "block" to the word boundary or not. > johannes > -- -------------------------------------------------------- Roberto Riggio, Ph.D. CREATE-NET Network& Security Solutions for Pervasive Computing Systems (iNSPIRE) Senior Researcher Via alla Cascata 56/D - 38123 Povo Trento (Italy) e-mail: roberto.riggio-2TmCWn7/4sHOQU1ULcgDhA@public.gmane.org Tel: (+39) 0461 408400 - interno/extension 708 Fax: (+39) 0461 421157 www.create-net.org/~rriggio -------------------------------------------------------- The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited according to the Italian Law 196/2003 of the Legislature. If you received this in error, please contact the sender and delete the material from any computer. Le informazioni contenute in questo messaggio di posta elettronica e nei file allegati sono da considerarsi strettamente riservate. Il loro utilizzo e' consentito esclusivamente al destinatario del messaggio, per le finalita' indicate nel messaggio stesso. Qualora riceveste questo messaggio senza esserne il destinatario, Vi preghiamo cortesemente di darcene notizia via e-mail e di procedere alla cancellazione del messaggio stesso dal Vostro sistema. Trattenere il messaggio stesso, divulgarlo anche in parte, distribuirlo ad altri soggetti, copiarlo, od utilizzarlo per finalita' diverse, costituisce comportamento contrario ai principi dettati dal D. Lgs. 196/2003.