From owner-freebsd-net@freebsd.org Wed Mar 21 03:43:37 2018 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B5F87F66989 for ; Wed, 21 Mar 2018 03:43:37 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from hz.grosbein.net (hz.grosbein.net [78.47.246.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "hz.grosbein.net", Issuer "hz.grosbein.net" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 3844379588 for ; Wed, 21 Mar 2018 03:43:36 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from eg.sd.rdtc.ru (root@eg.sd.rdtc.ru [62.231.161.221] (may be forged)) by hz.grosbein.net (8.15.2/8.15.2) with ESMTPS id w2L3hPSP084703 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 21 Mar 2018 04:43:26 +0100 (CET) (envelope-from eugen@grosbein.net) X-Envelope-From: eugen@grosbein.net X-Envelope-To: michael.tuexen@lurchi.franken.de Received: from eg.sd.rdtc.ru (eugen@localhost [127.0.0.1]) by eg.sd.rdtc.ru (8.15.2/8.15.2) with ESMTP id w2L3hEZv036778; Wed, 21 Mar 2018 10:43:14 +0700 (+07) (envelope-from eugen@grosbein.net) Subject: Re: Raw Sockets: Two Questions To: Michael Tuexen References: <98551.1521576540@segfault.tristatelogic.com> <5AB1A9C5.9050707@grosbein.net> Cc: "Ronald F. Guilmette" , freebsd-net@freebsd.org From: Eugene Grosbein X-Enigmail-Draft-Status: N1110 Message-ID: <5AB1D4D2.8000001@grosbein.net> Date: Wed, 21 Mar 2018 10:43:14 +0700 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=2.2 required=5.0 tests=BAYES_00, LOCAL_FROM, RDNS_NONE, T_DATE_IN_FUTURE_96_Q autolearn=no autolearn_force=no version=3.4.1 X-Spam-Report: * 0.0 T_DATE_IN_FUTURE_96_Q Date: is 4 days to 4 months after Received: * date * -2.3 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * 2.6 LOCAL_FROM From my domains * 1.9 RDNS_NONE Delivered to internal network by a host with no rDNS X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on hz.grosbein.net X-Spam-Level: ** X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Mar 2018 03:43:37 -0000 On 21.03.2018 08:03, Michael Tuexen wrote: >> On 21. Mar 2018, at 00:39, Eugene Grosbein wrote: >> >> 21.03.2018 3:09, Ronald F. Guilmette wrote: >> >>> I'm going to be doing some stuff with raw sockets pretty soon, and >>> while scrounging around, looking for some nice coding examples, I >>> found the following very curious comment on one particular message >>> board: >>> >>> https://stackoverflow.com/questions/7048448/raw-sockets-on-bsd-operating-systems >>> >>> "Using raw sockets isn't hard but it's not entirely portable. For >>> instance, both in BSD and in Linux you can send whatever you want, >>> but in BSD you can't receive anything that has a handler (like TCP >>> and UDP)." >>> >>> So, first question: Is the above comment actually true & accurate? >> >> Not for FreeBSD. > Are you saying that I can receive on a raw socket SCTP, TCP and UDP packets? No. I'm saying one can send/receive RAW IP packets no matter are they SCTP, TCP or UDP or something else by means of libdnet. It uses raw sockets and BPF internally but hides this complexity. nmap uses it just fine.