From 96ea3a1e2d317e7ecb6b65dc65c9dd917905a6a8 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Sun, 1 Feb 2026 15:33:17 +0100 Subject: can: add CAN skb extension infrastructure To remove the private CAN bus skb headroom infrastructure 8 bytes need to be stored in the skb. The skb extensions are a common pattern and an easy and efficient way to hold private data travelling along with the skb. We only need the skb_ext_add() and skb_ext_find() functions to allocate and access CAN specific content as the skb helpers to copy/clone/free skbs automatically take care of skb extensions and their final removal. This patch introduces the complete CAN skb extensions infrastructure: - add struct can_skb_ext in new file include/net/can.h - add include/net/can.h in MAINTAINERS - add SKB_EXT_CAN to skbuff.c and skbuff.h - select SKB_EXTENSIONS in Kconfig when CONFIG_CAN is enabled - check for existing CAN skb extensions in can_rcv() in af_can.c - add CAN skb extensions allocation at every skb_alloc() location - duplicate the skb extensions if cloning outgoing skbs (framelen/gw_hops) - introduce can_skb_ext_add() and can_skb_ext_find() helpers The patch also corrects an indention issue in the original code from 2018: Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202602010426.PnGrYAk3-lkp@intel.com/ Signed-off-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260201-can_skb_ext-v8-2-3635d790fe8b@hartkopp.net Signed-off-by: Paolo Abeni --- include/net/can.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 include/net/can.h (limited to 'include/net') diff --git a/include/net/can.h b/include/net/can.h new file mode 100644 index 000000000000..6db9e826f0e0 --- /dev/null +++ b/include/net/can.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */ +/* + * net/can.h + * + * Definitions for the CAN network socket buffer extensions + * + * Copyright (C) 2026 Oliver Hartkopp + * + */ + +#ifndef _NET_CAN_H +#define _NET_CAN_H + +/** + * struct can_skb_ext - skb extensions for CAN specific content + * @can_iif: ifindex of the first interface the CAN frame appeared on + * @can_framelen: cached echo CAN frame length for bql + * @can_gw_hops: can-gw CAN frame time-to-live counter + * @can_ext_flags: CAN skb extensions flags + */ +struct can_skb_ext { + int can_iif; + u16 can_framelen; + u8 can_gw_hops; + u8 can_ext_flags; +}; + +#endif /* _NET_CAN_H */ -- cgit v1.2.3