From owner-freebsd-current@FreeBSD.ORG Thu Nov 30 18:55:39 2006 Return-Path: X-Original-To: current@freebsd.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 9D9D616A508 for ; Thu, 30 Nov 2006 18:55:39 +0000 (UTC) (envelope-from rizzo@icir.org) Received: from xorpc.icir.org (xorpc.icir.org [192.150.187.68]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1E16043C9D for ; Thu, 30 Nov 2006 18:55:29 +0000 (GMT) (envelope-from rizzo@icir.org) Received: from xorpc.icir.org (localhost [127.0.0.1]) by xorpc.icir.org (8.12.11/8.13.6) with ESMTP id kAUItbrR069930; Thu, 30 Nov 2006 10:55:37 -0800 (PST) (envelope-from rizzo@xorpc.icir.org) Received: (from rizzo@localhost) by xorpc.icir.org (8.12.11/8.12.3/Submit) id kAUItbC7069929; Thu, 30 Nov 2006 10:55:37 -0800 (PST) (envelope-from rizzo) Date: Thu, 30 Nov 2006 10:55:37 -0800 From: Luigi Rizzo To: current@freebsd.org Message-ID: <20061130105537.A69725@xorpc.icir.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i Cc: Subject: byte swapped udp length in diskless bootp request ? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Nov 2006 18:55:39 -0000 i was just trying to diskless-boot a -current kernel, and when it was time for the kernel to acquire the address i was getting the usual DHCP/BOOTP timeout for server 255.255.255.255 Usually it is because of lack of connectivity, but a bit of inspection on the server showed (as you can see below) that the UDP len field is byte-swapped - the 05bc in the packet is in little-endian format, causing the server to reject it. I am trying to follow the code in sys/nfsclient/bootp_subr.c (which should send the packet) but it seemd to call sosend() (at line 755) to generate the packet, so it looks really strange that the bug is in such a central place... any ideas ? If that matters, the kernel is cross-compiled on a 6.2-RC1 box using a relatively fresh source tree. cheers luigi TCPDUMP OUTPUT ON THE SERVER SIDE: r1# tcpdump -nli em0 -s 0 -veX port 67 tcpdump: listening on em0, link-type EN10MB (Ethernet), capture size 65535 bytes 19:37:30.633525 00:40:f4:34:ad:09 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 1502: truncated-ip - 46645 bytes missing! (tos 0x0, ttl 1, id 83, offset 0, flags [none], proto: UDP (17), length: 48133, bad cksum 5bc (->fd95)!) 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:40:f4:34:ad:09, length: 48105, xid:0xffff0001, secs:400, flags: [Broadcast] Client Ethernet Address: 00:40:f4:34:ad:09 Vendor-rfc1048: MSZ:1460 VC:"FreeBSD:i386:7.0-CURRENT" DHCP:DISCOVER 0x0000: 4500 bc05 0053 0000 0111 05bc 0000 0000 E....S.......... 0x0010: ffff ffff 0044 0043 05bc 0000 0101 0600 .....D.C........ 0x0020: ffff 0001 0190 8000 0000 0000 0000 0000 ................ 0x0030: 0000 0000 0000 0000 0040 f434 ad09 0000 .........@.4.... ... and so on. The rest of the packet has all the good data up to 0x05a0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 0x05b0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 0x05c0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ ----------------------------------------------------------