From owner-freebsd-net@FreeBSD.ORG Mon Jul 11 15:50:37 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9D61A106566C for ; Mon, 11 Jul 2011 15:50:37 +0000 (UTC) (envelope-from mcins1@gmail.com) Received: from mail-ww0-f42.google.com (mail-ww0-f42.google.com [74.125.82.42]) by mx1.freebsd.org (Postfix) with ESMTP id 3544F8FC17 for ; Mon, 11 Jul 2011 15:50:36 +0000 (UTC) Received: by wwg11 with SMTP id 11so2334285wwg.1 for ; Mon, 11 Jul 2011 08:50:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:from:date:message-id:subject:to:content-type; bh=TKg8gBtw3Rtsq/tzRfZL6OHujhT2SH4Q7cZ0meEc4XU=; b=lnvJ5gzCKoB3qw1g1TqPAPrHV58cSdyW1D7vGdD7fMToSKXjff1S3eLV6a/gtRWc8+ VA7/kx6OQh7a1DTPUv8oNyUMmsnyQh/OwAPdAbcj5D1ULiel+EN0KBXjbNPpaHs4PYxZ HhGUmYvdmUMsotDp6qu8sKx9YVWsyiJbXfLJE= Received: by 10.216.68.200 with SMTP id l50mr4146201wed.106.1310398030203; Mon, 11 Jul 2011 08:27:10 -0700 (PDT) MIME-Version: 1.0 Received: by 10.216.90.67 with HTTP; Mon, 11 Jul 2011 08:26:49 -0700 (PDT) From: Matthew Cini Sarreo Date: Mon, 11 Jul 2011 17:26:49 +0200 Message-ID: To: freebsd-net@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: ESP Raw Socket: Returned IP packet incorrect X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Jul 2011 15:50:37 -0000 Hello all; I have recently encountered a problem when using raw sockets on FreeBSD 8 (8.0-RELEASE) when using ESP raw sockets. I have created a raw esp socket using: socket(AF_INET, SOCK_RAW, 50); which works fine. However, when there is a packet on the socket, recvfrom() returns a packet where the length bytes in the IP header are incorrect; they are swapped (MSB is placed in the LSB and vice-versa) tcpdump shows the following: tcpdump: listening on le0, link-type EN10MB (Ethernet), capture size 96 bytes 15:00:53.993810 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ESP (50), length 120) 10.0.251.228 > 10.0.252.231: ESP(spi=0xa0534f17,seq=0x3), length 100 0x0000: 4500 0078 0000 4000 4032 2d88 0a00 fbe4 0x0010: 0a00 fce7 a053 4f17 0000 0003 6885 8abd 0x0020: 2222 5ded 44dc 842f 3081 8fa3 bde4 2265 0x0030: 7438 2bf4 049c 664b 7dc4 44ef 1f6f 5e7d 0x0040: b8c1 482f 8c3b f488 a19a 3d9a d5fe ed9d 0x0050: b1c2 However, recvfrom() returns the following buffer: 4500 6400 0000 0040 4032 2D88 0A00 FBE4 0A00 FCE7 A053 4F17 0000 0003 6885 8ABD 2222 5DED 44DC 842F 3081 8FA3 BDE4 2265 7438 2BF4 049C 664B 7DC4 44EF 1F6F 5E7D B8C1 482F 8C3B F488 A19A 3D9A D5FE ED9D B1C2 As it is easy to see, the length is not correct (bytes 2 and 3 are 0x6400 instead of 0x0064) and it does not correspond to the value returned by recvfrom(). Is this a known issue? Am I missing some options for raw sockets that are required for FreeBSD? I have attempted this on a socket to a TUN interface (not with an ESP socket) and the buffer had the proper length; it seems to only happen with ESP. This code runs fine on multiple Linux distributions and on Windows; it was only noticed with FreeBSD. Could it be that there is some other ESP application running and interfering (I have not installed any; don't know if there are by default and I'm quite new to any of the BSDs)? Any help would be much appreciated. Matt