From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tihomir Heidelberg - 9a4gl <9a4gl@hamradio.hr> Subject: Re: AX.25 Kernel - problem - ax25_sendmsg returns EMSGSIZE ! Date: Mon, 08 Oct 2007 16:53:10 +0200 Message-ID: <470A4456.6000703@hamradio.hr> References: <47093A4E.5040409@hamradio.hr> <20071008082900.GB24782@cloud.net.au> <470A1035.5070900@hamradio.hr> <20071008134447.GA30451@cloud.net.au> Reply-To: 9a4gl@hamradio.hr Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20071008134447.GA30451@cloud.net.au> Sender: linux-hams-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii" To: linux-hams@vger.kernel.org Hi, Hamish Moffatt wrote: > socket(7) doesn't make any distinction between SOCK_DGRAM and > SOCK_SEQPACKET with regard to fragmentation. SOCK_SEQPACKET just adds > reliability and order. > > Hm, socket(2) or (7) ? Both documents do not mention fragmentation. But, according to socket(2), difference between SOCK_STREAM and SOCK_SEQPACKET is that first one supports out-of-band data which is not (easy) doable in AX.25 world. So, it is ok to use SOCK_SEQPACKET for what we/I call AX.25 connection. > Yes, except that it doesn't exactly make sense to have streams on a raw > socket (which is I guess why they are not supported for AX.25). Streams > would be implemented by the transport layer and above, which is above > what a raw socket provides. > Hm, as I see AX.25 sockets supports SOCK_DGRAM, SOCK_SEQPACKET and SOCK_RAW. I am not talking about raw and I am not using raw socket. IMHO, users of raw sockets should be aware of MTU and I would not fragment raw sockets in kernel. What I want is to have SOCK_SEQPACKET reliable, accepting any amount of data and on write returning number of bytes accepted. I do not care much if fragmentation will take place or not, but currently I do not see any reason why not. 73 de Tihomir Heidelberg, 9a4gl