From mboxrd@z Thu Jan 1 00:00:00 1970 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 mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33BADFF8873 for ; Thu, 30 Apr 2026 16:39:58 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 3C4564021F; Thu, 30 Apr 2026 18:39:57 +0200 (CEST) Received: from inbox.dpdk.org (inbox.dpdk.org [95.142.172.178]) by mails.dpdk.org (Postfix) with ESMTP id 9ED01400D6 for ; Thu, 30 Apr 2026 18:39:55 +0200 (CEST) Received: by inbox.dpdk.org (Postfix, from userid 33) id 8F9404B0FD; Thu, 30 Apr 2026 18:39:55 +0200 (CEST) From: bugzilla@dpdk.org To: dev@dpdk.org Subject: [DPDK/other Bug 1941] net/tap: wrong ptype leads to checksum failure Date: Thu, 30 Apr 2026 16:39:55 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: DPDK X-Bugzilla-Component: other X-Bugzilla-Version: 26.03 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: ktraynor@redhat.com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: Normal X-Bugzilla-Assigned-To: dev@dpdk.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter target_milestone Message-ID: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All MIME-Version: 1.0 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org http://bugs.dpdk.org/show_bug.cgi?id=3D1941 Bug ID: 1941 Summary: net/tap: wrong ptype leads to checksum failure Product: DPDK Version: 26.03 Hardware: All OS: All Status: UNCONFIRMED Severity: normal Priority: Normal Component: other Assignee: dev@dpdk.org Reporter: ktraynor@redhat.com Target Milestone: --- Adding bugzilla for issue reported by Robin in [0], so we can link in relea= se notes: Since commit 1f250674085a ("net: fix packet type for stacked VLAN"), rte_net_get_ptype() uses |=3D to set the L2 ptype inside the VLAN parsing loop. Since pkt_type is already initialized with RTE_PTYPE_L2_ETHER (0x1), or-ing it with RTE_PTYPE_L2_ETHER_VLAN (0x6) results in RTE_PTYPE_L2_ETHER_QINQ (0x7). This causes single VLAN frames to be misidentified as QinQ. This was detected while testing DPDK 25.11.1 in grout. The net/tap driver calls rte_net_get_ptype() in tap_verify_csum() to determine the L2 header length. With the wrong ptype, l2_len is set to 22 (ether + QinQ =3D 14 + 8) instead of 18 (ether + VLAN =3D 14 + 4), shifting the IP header pointer by 4 bytes. The checksum is then computed on garbage data, causing valid packets to be dropped. [0] https://mails.dpdk.org/archives/dev/2026-April/336248.html --=20 You are receiving this mail because: You are the assignee for the bug.=