Previously there was a race that could allow the mctp_dev refcount
to hit zero:
rcu_read_lock();
mdev = __mctp_dev_get(dev);
// mctp_unregister() happens here, mdev->refs hits zero
mctp_dev_hold(dev);
rcu_read_unlock();
Now we make __mctp_dev_get() take the hold itself. It is safe to test
against the zero refcount because __mctp_dev_get() is called holding
rcu_read_lock and mctp_dev uses kfree_rcu().
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change adds some basic sanity checks for the source and dest
headers of packets on initial receive.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently, we have mctp_address_ok(), which checks if an EID is in the
"valid" range of 8-254 inclusive. However, 0 and 255 may also be valid
addresses, depending on context. 0 is the NULL EID, which may be set
when physical addressing is used. 255 is valid as a destination address
for broadcasts.
This change renames mctp_address_ok to mctp_address_unicast, and adds
similar helpers for broadcast and null EIDs, which will be used in an
upcoming commit.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Clang static analysis reports this problem
route.c:425:4: warning: Use of memory after it is freed
trace_mctp_key_acquire(key);
^~~~~~~~~~~~~~~~~~~~~~~~~~~
When mctp_key_add() fails, key is freed but then is later
used in trace_mctp_key_acquire(). Add an else statement
to use the key only when mctp_key_add() is successful.
Fixes: 4f9e1ba6de ("mctp: Add tracepoints for tag/key handling")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change adds a couple of new ioctls for mctp sockets:
SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG. These ioctls provide facilities
for explicit allocation / release of tags, overriding the automatic
allocate-on-send/release-on-reply and timeout behaviours. This allows
userspace more control over messages that may not fit a simple
request/response model.
In order to indicate a pre-allocated tag to the sendmsg() syscall, we
introduce a new flag to the struct sockaddr_mctp.smctp_tag value:
MCTP_TAG_PREALLOC.
Additional changes from Jeremy Kerr <jk@codeconstruct.com.au>.
Contains a fix that was:
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, we require an exact match on an incoming packet's dest
address, and the key's local_addr field.
In a future change, we may want to set up a key before packets are
routed, meaning we have no local address to match on.
This change allows key lookups to match on local_addr = MCTP_ADDR_ANY.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, we have a couple of paths that check that an EID matches, or
the match value is MCTP_ADDR_ANY.
Rather than open coding this, add a little helper.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The 'if (dev)' statement already move into dev_{put , hold}, so remove
redundant if statements.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
We need to test against the existing route type, not
the rtm_type in the netlink request.
Fixes: 83f0a0b728 ("mctp: Specify route types, require rtm_type in RTM_*ROUTE messages")
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we have an extension for MCTP data in skbs, populate the flow
when a key has been created for the packet, and add a device driver
operation to inform of flow destruction.
Includes a fix for a warning with test builds:
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
In a future change, we will want the key available for future use after
allocating a new tag. This change returns the key from
mctp_alloc_local_tag, rather than just key->tag.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change allows an extended address struct - struct sockaddr_mctp_ext
- to be passed to sendmsg/recvmsg. This allows userspace to specify
output ifindex and physical address information (for sendmsg) or receive
the input ifindex/physaddr for incoming messages (for recvmsg). This is
typically used by userspace for MCTP address discovery and assignment
operations.
The extended addressing facility is conditional on a new sockopt:
MCTP_OPT_ADDR_EXT; userspace must explicitly enable addressing before
the kernel will consume/populate the extended address data.
Includes a fix for an uninitialised var:
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
mctp_key_alloc() returns a key already referenced.
The mctp_route_input() path receives a packet for a bind socket and
allocates a key. It passes the key to mctp_key_add() which takes a
refcount and adds the key to lists. mctp_route_input() should then
release its own refcount when setting the key pointer to NULL.
In the mctp_alloc_local_tag() path (for mctp_local_output()) we
similarly need to unref the key before returning (mctp_reserve_tag()
takes a refcount and adds the key to lists).
Fixes: 73c618456d ("mctp: locking, lifetime and validity changes for sk_keys")
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change adds the first kunit test for the mctp subsystem, and an
initial test for the fragmentation path.
We're adding tests under a new net/mctp/test/ directory.
Incorporates a fix for module configs:
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 4f42ad2011, reversing
changes made to ea2dd331bf.
These chanfges break the build when mctp is modular.
Signed-off-by: David S. Miller <davem@davemloft.net>
This change adds the first kunit test for the mctp subsystem, and an
initial test for the fragmentation path.
We're adding tests under a new net/mctp/test/ directory.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
A route's RTAX_MTU can be set in nested RTAX_METRICS
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The tag allocation, release and bind events are somewhat opaque outside
the kernel; this change adds a few tracepoints to assist in
instrumentation and debugging.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, a MCTP (local-eid,remote-eid,tag) tuple is allocated to a
socket on send, and only expires when the socket is closed.
This change introduces a tag timeout, freeing the tuple after a fixed
expiry - currently six seconds. This is greater than (but close to) the
max response timeout in upper-layer bindings.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, we tie the struct mctp_dev lifetime to the underlying struct
net_device, and hold/put that device as a proxy for a separate mctp_dev
refcount. This works because we're not holding any references to the
mctp_dev that are different from the netdev lifetime.
In a future change we'll break that assumption though, as we'll need to
hold mctp_dev references in a workqueue, which might live past the
netdev unregister notification.
In order to support that, this change introduces a refcount on the
mctp_dev, currently taken by the net_device->mctp_ptr reference, and
released on netdev unregister events. We can then use this for future
references that might outlast the net device.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
We will want to invalidate sk_keys in a future change, which will
require a boolean flag to mark invalidated items in the socket & net
namespace lists. We'll also need to take a reference to keys, held over
non-atomic contexts, so we need a refcount on keys also.
This change adds a validity flag (currently always true) and refcount to
struct mctp_sk_key. With a refcount on the keys, using RCU no longer
makes much sense; we have exact indications on the lifetime of keys. So,
we also change the RCU list traversal to a locked implementation.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
We may need to receive packets addressed to the null EID (==0), but
addressed to us at the physical layer.
This change adds a lookup for local routes when we see a packet
addressed to EID 0, and a local phys address.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allowing TUN is useful for testing, to route packets to userspace or to
tunnel between machines.
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The kernel test robot reports:
[ 843.509974][ T345] =============================
[ 843.524220][ T345] WARNING: suspicious RCU usage
[ 843.538791][ T345] 5.14.0-rc2-00606-g889b7da23abf #1 Not tainted
[ 843.553617][ T345] -----------------------------
[ 843.567412][ T345] net/mctp/route.c:310 RCU-list traversed in non-reader section!!
- we're missing the rcu read lock acquire around the destruction path.
This change adds the acquire/release - the path is already atomic, and
we're using the _rcu list iterators.
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change adds a 'type' attribute to routes, which can be parsed from
a RTM_NEWROUTE message. This will help to distinguish local vs. peer
routes in a future change.
This means userspace will need to set a correct rtm_type in RTM_NEWROUTE
and RTM_DELROUTE messages; we currently only accept RTN_UNICAST.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20210810023834.2231088-1-jk@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently we have a compile-time default network
(MCTP_INITIAL_DEFAULT_NET). This change introduces a default_net field
on the net namespace, allowing future configuration for new interfaces.
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we have a neighbour implementation, hook it up to the output
path to set the dest hardware address for outgoing packets.
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change implements MCTP fragmentation (based on route & device MTU),
and corresponding reassembly.
The MCTP specification only allows for fragmentation on the originating
message endpoint, and reassembly on the destination endpoint -
intermediate nodes do not need to reassemble/refragment. Consequently,
we only fragment in the local transmit path, and reassemble
locally-bound packets. Messages are required to be in-order, so we
simply cancel reassembly on out-of-order or missing packets.
In the fragmentation path, we just break up the message into MTU-sized
fragments; the skb structure is a simple copy for now, which we can later
improve with a shared data implementation.
For reassembly, we keep track of incoming message fragments using the
existing tag infrastructure, allocating a key on the (src,dest,tag)
tuple, and reassembles matching fragments into a skb->frag_list.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Start filling-out the socket syscalls: bind, sendmsg & recvmsg.
This requires an input route implementation, so we add to
mctp_route_input, allowing lookups on binds & message tags. This just
handles single-packet messages at present, we will add fragmentation in
a future change.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change adds RTM_GETROUTE, RTM_NEWROUTE & RTM_DELROUTE handlers,
allowing management of the MCTP route table.
Includes changes from Jeremy Kerr <jk@codeconstruct.com.au>.
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a simple routing table, and a couple of route output handlers, and
the mctp packet_type & handler.
Includes changes from Matt Johnston <matt@codeconstruct.com.au>.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
