diff options
Diffstat (limited to 'Documentation/networking/can.txt')
| -rw-r--r-- | Documentation/networking/can.txt | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt index 0a2859a8ee7e..5abad1e921ca 100644 --- a/Documentation/networking/can.txt +++ b/Documentation/networking/can.txt @@ -22,7 +22,8 @@ This file contains 4.1.3 RAW socket option CAN_RAW_LOOPBACK 4.1.4 RAW socket option CAN_RAW_RECV_OWN_MSGS 4.1.5 RAW socket option CAN_RAW_FD_FRAMES - 4.1.6 RAW socket returned message flags + 4.1.6 RAW socket option CAN_RAW_JOIN_FILTERS + 4.1.7 RAW socket returned message flags 4.2 Broadcast Manager protocol sockets (SOCK_DGRAM) 4.2.1 Broadcast Manager operations 4.2.2 Broadcast Manager message flags @@ -601,7 +602,22 @@ solution for a couple of reasons: CAN FD frames by checking if the device maximum transfer unit is CANFD_MTU. The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall. - 4.1.6 RAW socket returned message flags + 4.1.6 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 + applied (see 4.1.1). + + This socket option joines 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. + + This is useful especially when the filterset is a combination of filters + where the CAN_INV_FILTER flag is set in order to notch single CAN IDs or + CAN ID ranges from the incoming traffic. + + 4.1.7 RAW socket returned message flags When using recvmsg() call, the msg->msg_flags may contain following flags: |