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Diffstat (limited to 'Documentation/networking/can.rst')
| -rw-r--r-- | Documentation/networking/can.rst | 38 |
1 files changed, 20 insertions, 18 deletions
diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst index d7e1ada905b2..b018ce346392 100644 --- a/Documentation/networking/can.rst +++ b/Documentation/networking/can.rst @@ -444,6 +444,24 @@ definitions are specified for CAN specific MTUs in include/linux/can.h: #define CANFD_MTU (sizeof(struct canfd_frame)) == 72 => CAN FD frame +Returned Message Flags +---------------------- + +When using the system call recvmsg(2) on a RAW or a BCM socket, the +msg->msg_flags field may contain the following flags: + +MSG_DONTROUTE: + set when the received frame was created on the local host. + +MSG_CONFIRM: + set when the frame was sent via the socket it is received on. + This flag can be interpreted as a 'transmission confirmation' when the + CAN driver supports the echo of frames on driver level, see + :ref:`socketcan-local-loopback1` and :ref:`socketcan-local-loopback2`. + (Note: In order to receive such messages on a RAW socket, + CAN_RAW_RECV_OWN_MSGS must be set.) + + .. _socketcan-raw-sockets: RAW Protocol Sockets with can_filters (SOCK_RAW) @@ -681,10 +699,10 @@ RAW socket option CAN_RAW_JOIN_FILTERS The CAN_RAW socket can set multiple CAN identifier specific filters that lead to multiple filters in the af_can.c filter processing. These filters -are indenpendent from each other which leads to logical OR'ed filters when +are independent from each other which leads to logical OR'ed filters when applied (see :ref:`socketcan-rawfilter`). -This socket option joines the given CAN filters in the way that only CAN +This socket option joins the given CAN filters in the way that only CAN frames are passed to user space that matched *all* given CAN filters. The semantic for the applied filters is therefore changed to a logical AND. @@ -693,22 +711,6 @@ where the CAN_INV_FILTER flag is set in order to notch single CAN IDs or CAN ID ranges from the incoming traffic. -RAW Socket Returned Message Flags -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -When using recvmsg() call, the msg->msg_flags may contain following flags: - -MSG_DONTROUTE: - set when the received frame was created on the local host. - -MSG_CONFIRM: - set when the frame was sent via the socket it is received on. - This flag can be interpreted as a 'transmission confirmation' when the - CAN driver supports the echo of frames on driver level, see - :ref:`socketcan-local-loopback1` and :ref:`socketcan-local-loopback2`. - In order to receive such messages, CAN_RAW_RECV_OWN_MSGS must be set. - - Broadcast Manager Protocol Sockets (SOCK_DGRAM) ----------------------------------------------- |