From patchwork Thu Jan 30 13:34:42 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 13954615 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B63D4C0218A for ; Thu, 30 Jan 2025 13:36:34 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tdUh9-0002dO-8d; Thu, 30 Jan 2025 08:34:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdUh5-0002bI-HI; Thu, 30 Jan 2025 08:34:55 -0500 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdUh3-0002Wj-Dq; Thu, 30 Jan 2025 08:34:54 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id E7829E3040; Thu, 30 Jan 2025 16:34:18 +0300 (MSK) Received: from gandalf.tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with ESMTP id D76111A7F87; Thu, 30 Jan 2025 16:34:47 +0300 (MSK) Received: by gandalf.tls.msk.ru (Postfix, from userid 1000) id C7C7C52404; Thu, 30 Jan 2025 16:34:47 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: Laurent Vivier , qemu-trivial@nongnu.org, akihiko.odaki@daynix.com, Michael Tokarev Subject: [PULL 2/7] net/dump: Correctly compute Ethernet packet offset Date: Thu, 30 Jan 2025 16:34:42 +0300 Message-Id: <20250130133447.873566-3-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250130133447.873566-1-mjt@tls.msk.ru> References: <20250130133447.873566-1-mjt@tls.msk.ru> MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Laurent Vivier When a packet is sent with QEMU_NET_PACKET_FLAG_RAW by QEMU it never includes virtio-net header even if qemu_get_vnet_hdr_len() is not 0, and filter-dump is not managing this case. The only user of QEMU_NET_PACKET_FLAG_RAW is announce_self, we can show the problem using it and tcpddump: - QEMU parameters: .. -monitor stdio \ -netdev bridge,id=netdev0,br=virbr0 \ -device virtio-net,mac=9a:2b:2c:2d:2e:2f,netdev=netdev0 \ -object filter-dump,netdev=netdev0,file=log.pcap,id=pcap0 - HMP command: (qemu) announce_self - TCP dump: $ tcpdump -nxr log.pcap without the fix: 08:00:06:04:00:03 > 2e:2f:80:35:00:01, ethertype Unknown (0x9a2b), length 50: 0x0000: 2c2d 2e2f 0000 0000 9a2b 2c2d 2e2f 0000 0x0010: 0000 0000 0000 0000 0000 0000 0000 0000 0x0020: 0000 0000 with the fix: ARP, Reverse Request who-is 9a:2b:2c:2d:2e:2f tell 9a:2b:2c:2d:2e:2f, length 46 0x0000: 0001 0800 0604 0003 9a2b 2c2d 2e2f 0000 0x0010: 0000 9a2b 2c2d 2e2f 0000 0000 0000 0000 0x0020: 0000 0000 0000 0000 0000 0000 0000 Fixes: 481c52320a26 ("net: Strip virtio-net header when dumping") Cc: akihiko.odaki@daynix.com Signed-off-by: Laurent Vivier Reviewed-by: Akihiko Odaki Reviewed-by: Michael Tokarev Signed-off-by: Michael Tokarev --- net/dump.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/dump.c b/net/dump.c index d7dd2ce461..140215aa10 100644 --- a/net/dump.c +++ b/net/dump.c @@ -155,7 +155,8 @@ static ssize_t filter_dump_receive_iov(NetFilterState *nf, NetClientState *sndr, { NetFilterDumpState *nfds = FILTER_DUMP(nf); - dump_receive_iov(&nfds->ds, iov, iovcnt, qemu_get_vnet_hdr_len(nf->netdev)); + dump_receive_iov(&nfds->ds, iov, iovcnt, flags & QEMU_NET_PACKET_FLAG_RAW ? + 0 : qemu_get_vnet_hdr_len(nf->netdev)); return 0; }