kernel/linux.git/include/net/mctp.h, branch v7.1-rc5

net: mctp: fix don't require received header reserved bits to be zero

2026-04-20T18:46:57+00:00

From the MCTP Base specification (DSP0236 v1.2.1), the first byte of the MCTP header contains a 4 bit reserved field, and 4 bit version. On our current receive path, we require those 4 reserved bits to be zero, but the 9500-8i card is non-conformant, and may set these reserved bits. DSP0236 states that the reserved bits must be written as zero, and ignored when read. While the device might not conform to the former, we should accept these message to conform to the latter. Relax our check on the MCTP version byte to allow non-zero bits in the reserved field. Fixes: 889b7da23abf ("mctp: Add initial routing framework") Signed-off-by: Yuan Zhaoming Cc: stable@vger.kernel.org Acked-by: Jeremy Kerr Link: https://patch.msgid.link/20260417141340.5306-1-yuanzhaoming901030@126.com Signed-off-by: Jakub Kicinski

net: mctp: perform source address lookups when we populate our dst

2026-04-02T11:31:36+00:00

Rather than querying the output device for its address in mctp_local_output, set up the source address when we're populating the dst structure. If no address is assigned, use MCTP_ADDR_NULL. This will allow us more flexibility when routing for NULL-source-eid cases. For now though, we still reject a NULL source address in the output path. We need to update the tests a little, so that addresses are assigned before we do the dst lookups. Signed-off-by: Jeremy Kerr Link: https://patch.msgid.link/20260331-dev-mctp-null-eids-v1-1-b4d047372eaf@codeconstruct.com.au Signed-off-by: Paolo Abeni

net: mctp: Allow limiting binds to a peer address

2025-07-15T10:08:39+00:00

Prior to calling bind() a program may call connect() on a socket to restrict to a remote peer address. Using connect() is the normal mechanism to specify a remote network peer, so we use that here. In MCTP connect() is only used for bound sockets - send() is not available for MCTP since a tag must be provided for each message. The smctp_type must match between connect() and bind() calls. Signed-off-by: Matt Johnston Link: https://patch.msgid.link/20250710-mctp-bind-v4-6-8ec2f6460c56@codeconstruct.com.au Signed-off-by: Paolo Abeni

net: mctp: add gateway routing support

2025-07-08T10:39:24+00:00

This change allows for gateway routing, where a route table entry may reference a routable endpoint (by network and EID), instead of routing directly to a netdevice. We add support for a RTM_GATEWAY attribute for netlink route updates, with an attribute format of: struct mctp_fq_addr { unsigned int net; mctp_eid_t eid; } - we need the net here to uniquely identify the target EID, as we no longer have the device reference directly (which would provide the net id in the case of direct routes). This makes route lookups recursive, as a route lookup that returns a gateway route must be resolved into a direct route (ie, to a device) eventually. We provide a limit to the route lookups, to prevent infinite loop routing. The route lookup populates a new 'nexthop' field in the dst structure, which now specifies the key for the neighbour table lookup on device output, rather than using the packet destination address directly. Signed-off-by: Jeremy Kerr Link: https://patch.msgid.link/20250702-dev-forwarding-v5-13-1468191da8a4@codeconstruct.com.au Signed-off-by: Paolo Abeni

net: mctp: separate cb from direct-addressing routing

2025-07-08T10:39:23+00:00

Now that we have the dst->haddr populated by sendmsg (when extended addressing is in use), we no longer need to stash the link-layer address in the skb->cb. Instead, only use skb->cb for incoming lladdr data. While we're at it: remove cb->src, as was never used. Signed-off-by: Jeremy Kerr Link: https://patch.msgid.link/20250702-dev-forwarding-v5-4-1468191da8a4@codeconstruct.com.au Signed-off-by: Paolo Abeni

net: mctp: separate routing database from routing operations

2025-07-08T10:39:23+00:00

This change adds a struct mctp_dst, representing the result of a routing lookup. This decouples the struct mctp_route from the actual implementation of a routing operation. This will allow for future routing changes which may require more involved lookup logic, such as gateway routing - which may require multiple traversals of the routing table. Since we only use the struct mctp_route at lookup time, we no longer hold routes over a routing operation, as we only need it to populate the dst. However, we do hold the dev while the dst is active. This requires some changes to the route test infrastructure, as we no longer have a mock route to handle the route output operation, and transient dsts are created by the routing code, so we can't override them as easily. Instead, we use kunit->priv to stash a packet queue, and a custom dst_output function queues into that packet queue, which we can use for later expectations. Signed-off-by: Jeremy Kerr Link: https://patch.msgid.link/20250702-dev-forwarding-v5-3-1468191da8a4@codeconstruct.com.au Signed-off-by: Paolo Abeni

net: mctp: Remove unnecessary cast in mctp_cb

2025-03-21T17:18:12+00:00

The void * cast in mctp_cb is unnecessary as it's already been done at the start of the function. Signed-off-by: Herbert Xu Acked-by: Jeremy Kerr Link: https://patch.msgid.link/Z9PwOQeBSYlgZlHq@gondor.apana.org.au Signed-off-by: Paolo Abeni

net: mctp: Expose transport binding identifier via IFLA attribute

2024-11-09T17:04:54+00:00

MCTP control protocol implementations are transport binding dependent. Endpoint discovery is mandatory based on transport binding. Message timing requirements are specified in each respective transport binding specification. However, we currently have no means to get this information from MCTP links. Add a IFLA_MCTP_PHYS_BINDING netlink link attribute, which represents the transport type using the DMTF DSP0239-defined type numbers, returned as part of RTM_GETLINK data. We get an IFLA_MCTP_PHYS_BINDING attribute for each MCTP link, for example: - 0x00 (unspec) for loopback interface; - 0x01 (SMBus/I2C) for mctpi2c%d interfaces; and - 0x05 (serial) for mctpserial%d interfaces. Signed-off-by: Khang Nguyen Reviewed-by: Matt Johnston Link: https://patch.msgid.link/20241105071915.821871-1-khangng@os.amperecomputing.com Signed-off-by: Jakub Kicinski

mctp: Handle error of rtnl_register_module().

2024-10-10T13:39:35+00:00

Since introduced, mctp has been ignoring the returned value of rtnl_register_module(), which could fail silently. Handling the error allows users to view a module as an all-or-nothing thing in terms of the rtnetlink functionality. This prevents syzkaller from reporting spurious errors from its tests, where OOM often occurs and module is automatically loaded. Let's handle the errors by rtnl_register_many(). Fixes: 583be982d934 ("mctp: Add device handling and netlink interface") Fixes: 831119f88781 ("mctp: Add neighbour netlink interface") Fixes: 06d2f4c583a7 ("mctp: Add netlink route management") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Jeremy Kerr Signed-off-by: Paolo Abeni

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-02-29T22:24:56+00:00

Cross-merge networking fixes after downstream PR. Conflicts: net/mptcp/protocol.c adf1bb78dab5 ("mptcp: fix snd_wnd initialization for passive socket") 9426ce476a70 ("mptcp: annotate lockless access for RX path fields") https://lore.kernel.org/all/20240228103048.19255709@canb.auug.org.au/ Adjacent changes: drivers/dpll/dpll_core.c 0d60d8df6f49 ("dpll: rely on rcu for netdev_dpll_pin()") e7f8df0e81bf ("dpll: move xa_erase() call in to match dpll_pin_alloc() error path order") drivers/net/veth.c 1ce7d306ea63 ("veth: try harder when allocating queue memory") 0bef512012b1 ("net: add netdev_lockdep_set_classes() to virtual drivers") drivers/net/wireless/intel/iwlwifi/mvm/d3.c 8c9bef26e98b ("wifi: iwlwifi: mvm: d3: implement suspend with MLO") 78f65fbf421a ("wifi: iwlwifi: mvm: ensure offloading TID queue exists") net/wireless/nl80211.c f78c1375339a ("wifi: nl80211: reject iftype change with mesh ID change") 414532d8aa89 ("wifi: cfg80211: use IEEE80211_MAX_MESH_ID_LEN appropriately") Signed-off-by: Jakub Kicinski