kernel/linux.git/drivers/net/can/vxcan.c, branch linux-7.0.y

can: gw: use can_gw_hops instead of sk_buff::csum_start

2026-02-05T10:58:40+00:00

As CAN skbs don't use IP checksums the skb->csum_start variable was used to store the can-gw CAN frame time-to-live counter together with skb->ip_summed set to CHECKSUM_UNNECESSARY. Remove the 'hack' using the skb->csum_start variable and move the content to can_skb_ext::can_gw_hops of the CAN skb extensions. The module parameter 'max_hops' has been reduced to a single byte to fit can_skb_ext::can_gw_hops as the maximum value to be stored is 6. Signed-off-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260201-can_skb_ext-v8-6-3635d790fe8b@hartkopp.net Signed-off-by: Paolo Abeni

can: add CAN skb extension infrastructure

2026-02-05T10:58:39+00:00

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

can: propagate CAN device capabilities via ml_priv

2026-01-15T08:52:04+00:00

Commit 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") caused a sequence of dependency and linker fixes. Instead of accessing CAN device internal data structures which caused the dependency problems this patch introduces capability information into the CAN specific ml_priv data which is accessible from both sides. With this change the CAN network layer can check the required features and the decoupling of the driver layer and network layer is restored. Fixes: 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") Cc: Marc Kleine-Budde Cc: Arnd Bergmann Cc: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260109144135.8495-3-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde

can: enable CAN XL for virtual CAN devices by default

2025-09-24T15:05:34+00:00

In commit 97edec3a11cf ("can: enable CAN FD for virtual CAN devices by default"), vcan and vxcan default MTU was set to CANFD_MTU by default. The reason was that users were confused on how to activate CAN FD on virtual interfaces. Following the introduction of CAN XL, the same logic should be applied. Set the MTU to CANXL_MTU by default. The users who really wish to use a Classical CAN only or a CAN FD virtual device can do respectively: $ ip link set vcan0 mtu 16 or $ ip link set vcan0 mtu 72 to force the old behaviour. Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20250923-can-fix-mtu-v3-4-581bde113f52@kernel.org Signed-off-by: Marc Kleine-Budde

net: Use link/peer netns in newlink() of rtnl_link_ops

2025-02-21T23:28:02+00:00

Add two helper functions - rtnl_newlink_link_net() and rtnl_newlink_peer_net() for netns fallback logic. Peer netns falls back to link netns, and link netns falls back to source netns. Convert the use of params->net in netdevice drivers to one of the helper functions for clarity. Signed-off-by: Xiao Liang Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250219125039.18024-4-shaw.leon@gmail.com Signed-off-by: Jakub Kicinski

rtnetlink: Pack newlink() params into struct

2025-02-21T23:28:02+00:00

There are 4 net namespaces involved when creating links: - source netns - where the netlink socket resides, - target netns - where to put the device being created, - link netns - netns associated with the device (backend), - peer netns - netns of peer device. Currently, two nets are passed to newlink() callback - "src_net" parameter and "dev_net" (implicitly in net_device). They are set as follows, depending on netlink attributes in the request. +------------+-------------------+---------+---------+ | peer netns | IFLA_LINK_NETNSID | src_net | dev_net | +------------+-------------------+---------+---------+ | | absent | source | target | | absent +-------------------+---------+---------+ | | present | link | link | +------------+-------------------+---------+---------+ | | absent | peer | target | | present +-------------------+---------+---------+ | | present | peer | link | +------------+-------------------+---------+---------+ When IFLA_LINK_NETNSID is present, the device is created in link netns first and then moved to target netns. This has some side effects, including extra ifindex allocation, ifname validation and link events. These could be avoided if we create it in target netns from the beginning. On the other hand, the meaning of src_net parameter is ambiguous. It varies depending on how parameters are passed. It is the effective link (or peer netns) by design, but some drivers ignore it and use dev_net instead. To provide more netns context for drivers, this patch packs existing newlink() parameters, along with the source netns, link netns and peer netns, into a struct. The old "src_net" is renamed to "net" to avoid confusion with real source netns, and will be deprecated later. The use of src_net are converted to params->net trivially. Signed-off-by: Xiao Liang Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250219125039.18024-3-shaw.leon@gmail.com Signed-off-by: Jakub Kicinski

rtnetlink: fix double call of rtnl_link_get_net_ifla()

2024-12-03T10:29:29+00:00

Currently rtnl_link_get_net_ifla() gets called twice when we create peer devices, once in rtnl_add_peer_net() and once in each ->newlink() implementation. This looks safer, however, it leads to a classic Time-of-Check to Time-of-Use (TOCTOU) bug since IFLA_NET_NS_PID is very dynamic. And because of the lack of checking error pointer of the second call, it also leads to a kernel crash as reported by syzbot. Fix this by getting rid of the second call, which already becomes redudant after Kuniyuki's work. We have to propagate the result of the first rtnl_link_get_net_ifla() down to each ->newlink(). Reported-by: syzbot+21ba4d5adff0b6a7cfc6@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=21ba4d5adff0b6a7cfc6 Fixes: 0eb87b02a705 ("veth: Set VETH_INFO_PEER to veth_link_ops.peer_type.") Fixes: 6b84e558e95d ("vxcan: Set VXCAN_INFO_PEER to vxcan_link_ops.peer_type.") Fixes: fefd5d082172 ("netkit: Set IFLA_NETKIT_PEER_INFO to netkit_link_ops.peer_type.") Cc: Kuniyuki Iwashima Signed-off-by: Cong Wang Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241129212519.825567-1-xiyou.wangcong@gmail.com Signed-off-by: Paolo Abeni

vxcan: Set VXCAN_INFO_PEER to vxcan_link_ops.peer_type.

2024-11-12T01:26:52+00:00

For per-netns RTNL, we need to prefetch the peer device's netns. Let's set rtnl_link_ops.peer_type and accordingly remove duplicated validation in ->newlink(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241108004823.29419-8-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

net: annotate writes on dev->mtu from ndo_change_mtu()

2024-05-07T23:19:14+00:00

Simon reported that ndo_change_mtu() methods were never updated to use WRITE_ONCE(dev->mtu, new_mtu) as hinted in commit 501a90c94510 ("inet: protect against too small mtu values.") We read dev->mtu without holding RTNL in many places, with READ_ONCE() annotations. It is time to take care of ndo_change_mtu() methods to use corresponding WRITE_ONCE() Signed-off-by: Eric Dumazet Reported-by: Simon Horman Closes: https://lore.kernel.org/netdev/20240505144608.GB67882@kernel.org/ Reviewed-by: Jacob Keller Reviewed-by: Sabrina Dubroca Reviewed-by: Simon Horman Acked-by: Shannon Nelson Link: https://lore.kernel.org/r/20240506102812.3025432-1-edumazet@google.com Signed-off-by: Jakub Kicinski

rtnetlink: prepare nla_put_iflink() to run under RCU

2024-02-26T11:46:12+00:00

We want to be able to run rtnl_fill_ifinfo() under RCU protection instead of RTNL in the future. This patch prepares dev_get_iflink() and nla_put_iflink() to run either with RTNL or RCU held. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller