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 B6DA4CA5FA1 for ; Tue, 29 Sep 2026 07:36:22 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 4A44840E19; Tue, 29 Sep 2026 09:36:21 +0200 (CEST) Received: from dkmailrelay1.smartsharesystems.com (smartserver.smartsharesystems.com [77.243.40.215]) by mails.dpdk.org (Postfix) with ESMTP id D8BDC4013F; Tue, 29 Sep 2026 09:36:19 +0200 (CEST) Received: from smartserver.smartsharesystems.com (smartserver.smartsharesys.local [192.168.4.10]) by dkmailrelay1.smartsharesystems.com (Postfix) with ESMTP id A5F15201FB; Tue, 29 Sep 2026 09:36:19 +0200 (CEST) Received: from dkrd4.smartsharesys.local ([192.168.4.26]) by smartserver.smartsharesystems.com with Microsoft SMTPSVC(6.0.3790.4675); Tue, 29 Sep 2026 09:36:19 +0200 From: =?UTF-8?q?Morten=20Br=C3=B8rup?= To: dev@dpdk.org, Thomas Monjalon Cc: =?UTF-8?q?Morten=20Br=C3=B8rup?= , stable@dpdk.org, Maxime Leroy , Stephen Hemminger Subject: [PATCH v2] net: revert add IPv6 traffic class and flow label fields Date: Tue, 29 Sep 2026 07:36:01 +0000 Message-ID: <20260929073601.2971197-1-mb@smartsharesystems.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260922163640.1144749-1-mb@smartsharesystems.com> References: <20260922163640.1144749-1-mb@smartsharesystems.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-OriginalArrivalTime: 29 Sep 2026 07:36:19.0236 (UTC) FILETIME=[37BF1E40:01DD4FE5] 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 The IPv6 header bitfields "version", "ds", "ecn", and "flow_label" are not organized correctly on little endian architectures. On little endian, a 32-bit bitfield is allocated from the least significant bit of the host order word, but "vtc_flow" is stored in network order. All four fields therefore read and write the wrong bits. For example, setting "version" to 6 writes 0x60 into the last byte of the word. "ds" and "flow_label" are not contiguous in memory on little endian, so no reordering of bitfields can express them. Reverted the patch introducing these bitfields. PS: There is a GCC attribute to fix this, but nothing similar is offered by Clang or MSVC: __attribute__((scalar_storage_order("big-endian"))) Bugzilla ID: 1679 Fixes: cba27998dc81 ("net: add IPv6 traffic class and flow label fields") Cc: stable@dpdk.org Reported-by: Maxime Leroy Signed-off-by: Morten Brørup Reviewed-by: Stephen Hemminger --- v2: Updated commit message and release notes. (AI advanced model) --- doc/guides/rel_notes/release_26_11.rst | 5 +++++ lib/net/rte_ip6.h | 18 +----------------- 2 files changed, 6 insertions(+), 17 deletions(-) diff --git a/doc/guides/rel_notes/release_26_11.rst b/doc/guides/rel_notes/release_26_11.rst index 4b3e5d995c..52ccc8f787 100644 --- a/doc/guides/rel_notes/release_26_11.rst +++ b/doc/guides/rel_notes/release_26_11.rst @@ -79,6 +79,11 @@ Removed Items ``rte_rib6_is_equal`` * table: ``RTE_LPM_IPV6_ADDR_SIZE`` + * net: Removed ``version``, ``ds``, ``ecn`` and ``flow_label`` + bitfields from ``struct rte_ipv6_hdr``. They accessed the wrong + bits on little endian. Use ``vtc_flow`` with the + ``RTE_IPV6_HDR_*_MASK`` and ``RTE_IPV6_HDR_*_SHIFT`` macros. + API Changes ----------- diff --git a/lib/net/rte_ip6.h b/lib/net/rte_ip6.h index d1abf1f5d5..25be328955 100644 --- a/lib/net/rte_ip6.h +++ b/lib/net/rte_ip6.h @@ -467,23 +467,7 @@ rte_ether_mcast_from_ipv6(struct rte_ether_addr *mac, const struct rte_ipv6_addr * IPv6 Header */ struct __rte_aligned(2) __rte_packed_begin rte_ipv6_hdr { - union { - rte_be32_t vtc_flow; /**< IP version, traffic class & flow label. */ - __extension__ - struct { -#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN - uint32_t flow_label:20; /**< Flow label */ - uint32_t ecn:2; /**< ECN */ - uint32_t ds:6; /**< Differentiated services */ - uint32_t version:4; /**< Version */ -#elif RTE_BYTE_ORDER == RTE_BIG_ENDIAN - uint32_t version:4; /**< Version */ - uint32_t ds:6; /**< Differentiated services */ - uint32_t ecn:2; /**< ECN */ - uint32_t flow_label:20; /**< Flow label */ -#endif - }; - }; + rte_be32_t vtc_flow; /**< IP version, traffic class & flow label. */ rte_be16_t payload_len; /**< IP payload size, including ext. headers */ uint8_t proto; /**< Protocol, next header. */ uint8_t hop_limits; /**< Hop limits. */ -- 2.43.0