On 10/18/2024 11:18 AM, Denis Kenzior wrote:
The current implementation of QRTR assumes that each entity on the QRTR
IPC bus is uniquely identifiable by its node/port combination, with
node/port combinations being used to route messages between entities.
However, this assumption of uniqueness is problematic in scenarios
where multiple devices with the same node/port combinations are
connected to the system. A practical example is a typical consumer PC
with multiple PCIe-based devices, such as WiFi cards or 5G modems, where
each device could potentially have the same node identifier set. In
such cases, the current QRTR protocol implementation does not provide a
mechanism to differentiate between these devices, making it impossible
to support communication with multiple identical devices.
This patch series addresses this limitation by introducing support for
a concept of an 'endpoint.' Multiple devices with conflicting node/port
combinations can be supported by assigning a unique endpoint identifier
to each one. Such endpoint identifiers can then be used to distinguish
between devices while sending and receiving messages over QRTR sockets.
The patch series maintains backward compatibility with existing clients:
the endpoint concept is added using auxiliary data that can be added to
recvmsg and sendmsg system calls. The QRTR socket interface is extended
as follows:
- Adds QRTR_ENDPOINT auxiliary data element that reports which endpoint
generated a particular message. This auxiliary data is only reported
if the socket was explicitly opted in using setsockopt, enabling the
QRTR_REPORT_ENDPOINT socket option. SOL_QRTR socket level was added
to facilitate this. This requires QRTR clients to be updated to use
recvmsg instead of the more typical recvfrom() or recv() use.
- Similarly, QRTR_ENDPOINT auxiliary data element can be included in
sendmsg() requests. This will allow clients to route QRTR messages
to the desired endpoint, even in cases of node/port conflict between
multiple endpoints.
- Finally, QRTR_BIND_ENDPOINT socket option is introduced. This allows
clients to bind to a particular endpoint (such as a 5G PCIe modem) if
they're only interested in receiving or sending messages to this
device.
NOTE: There is 32-bit unsafe use of radix_tree_insert in this patch set.
This follows the existing usage inside net/qrtr/af_qrtr.c in
qrtr_tx_wait(), qrtr_tx_resume() and qrtr_tx_flow_failed(). This was
done deliberately in order to keep the changes as minimal as possible
until it is known whether the approach outlined is generally acceptable.
Hi Denis,
Thank you for taking a stab at this long standing problem. We've been
going back and forth on how to solve this but haven't had anyone
dedicated to working out a solution. From a first pass I think this
looks very reasonable and I only have a few nitpicks here and there.
Hopefully Bjorn and Mani will provide more feedback.
Thanks!
Chris
Denis Kenzior (10):
net: qrtr: ns: validate msglen before ctrl_pkt use
net: qrtr: allocate and track endpoint ids
net: qrtr: support identical node ids
net: qrtr: Report sender endpoint in aux data
net: qrtr: Report endpoint for locally generated messages
net: qrtr: Allow sendmsg to target an endpoint
net: qrtr: allow socket endpoint binding
net: qrtr: Drop remote {NEW|DEL}_LOOKUP messages
net: qrtr: ns: support multiple endpoints
net: qrtr: mhi: Report endpoint id in sysfs
include/linux/socket.h | 1 +
include/uapi/linux/qrtr.h | 7 +
net/qrtr/af_qrtr.c | 297 +++++++++++++++++++++++++++++++------
net/qrtr/mhi.c | 14 ++
net/qrtr/ns.c | 299 +++++++++++++++++++++++---------------
net/qrtr/qrtr.h | 4 +
6 files changed, 459 insertions(+), 163 deletions(-)
