can_filter Struct Reference

Filter for reception of CAN messages. More...

Data Fields
uint32_t	can_id
	CAN ID which must match with incoming IDs after passing the mask.
uint32_t	can_mask
	Mask which is applied to incoming IDs.

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Detailed Description

Filter for reception of CAN messages.

This filter works as follows: A received CAN ID is AND'ed bitwise with can_mask and then compared to can_id. This also includes the CAN_EFF_FLAG and CAN_RTR_FLAG of CAN_xxx_FLAG. If this comparison is true, the message will be received by the socket. The logic can be inverted with the can_id flag CAN_INV_FILTER :

 if (can_id & CAN_INV_FILTER) {
    if ((received_can_id & can_mask) != (can_id & ~CAN_INV_FILTER))
       accept-message;
 } else {
    if ((received_can_id & can_mask) == can_id)
       accept-message;
 }

Multiple filters can be arranged in a filter list and set with Sockopts. If one of these filters matches a CAN ID upon reception of a CAN frame, this frame is accepted.

Examples:

rtcan_rtt.c, and rtcanrecv.c.

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Field Documentation

uint32_t can_filter::can_id

CAN ID which must match with incoming IDs after passing the mask.

The filter logic can be inverted with the flag CAN_INV_FILTER.

Examples:

rtcanrecv.c.

uint32_t can_filter::can_mask

Mask which is applied to incoming IDs.

See CAN ID masks if exactly one CAN ID should come through.

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The documentation for this struct was generated from the following file:

• include/rtdm/rtcan.h