include/linux/can/length.h

Source file repositories/reference/linux-study-clean/include/linux/can/length.h

File Facts

System: Linux kernel
Corpus path: include/linux/can/length.h
Extension: .h
Size: 9106 bytes
Lines: 307
Domain: Core OS
Bucket: Core Kernel Interface
Inferred role: Core OS: implementation source
Status: source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

linux/bits.h
linux/can.h
linux/can/netlink.h
linux/math.h

Detected Declarations

function can_frame_set_cc_len
function canfd_sanitize_len

Annotated Snippet

#ifndef _CAN_LENGTH_H
#define _CAN_LENGTH_H

#include <linux/bits.h>
#include <linux/can.h>
#include <linux/can/netlink.h>
#include <linux/math.h>

/*
 * Size of a Classical CAN Standard Frame header in bits
 *
 * Name of Field				Bits
 * ---------------------------------------------------------
 * Start Of Frame (SOF)				1
 * Arbitration field:
 *	base ID					11
 *	Remote Transmission Request (RTR)	1
 * Control field:
 *	IDentifier Extension bit (IDE)		1
 *	FD Format indicator (FDF)		1
 *	Data Length Code (DLC)			4
 *
 * including all fields preceding the data field, ignoring bitstuffing
 */
#define CAN_FRAME_HEADER_SFF_BITS 19

/*
 * Size of a Classical CAN Extended Frame header in bits
 *
 * Name of Field				Bits
 * ---------------------------------------------------------
 * Start Of Frame (SOF)				1
 * Arbitration field:
 *	base ID					11
 *	Substitute Remote Request (SRR)		1
 *	IDentifier Extension bit (IDE)		1
 *	ID extension				18
 *	Remote Transmission Request (RTR)	1
 * Control field:
 *	FD Format indicator (FDF)		1
 *	Reserved bit (r0)			1
 *	Data length code (DLC)			4
 *
 * including all fields preceding the data field, ignoring bitstuffing
 */
#define CAN_FRAME_HEADER_EFF_BITS 39

/*
 * Size of a CAN-FD Standard Frame in bits
 *
 * Name of Field				Bits
 * ---------------------------------------------------------
 * Start Of Frame (SOF)				1
 * Arbitration field:
 *	base ID					11
 *	Remote Request Substitution (RRS)	1
 * Control field:
 *	IDentifier Extension bit (IDE)		1
 *	FD Format indicator (FDF)		1
 *	Reserved bit (res)			1
 *	Bit Rate Switch (BRS)			1
 *	Error Status Indicator (ESI)		1
 *	Data length code (DLC)			4
 *
 * including all fields preceding the data field, ignoring bitstuffing
 */
#define CANFD_FRAME_HEADER_SFF_BITS 22

/*
 * Size of a CAN-FD Extended Frame in bits
 *
 * Name of Field				Bits
 * ---------------------------------------------------------
 * Start Of Frame (SOF)				1
 * Arbitration field:
 *	base ID					11
 *	Substitute Remote Request (SRR)		1
 *	IDentifier Extension bit (IDE)		1
 *	ID extension				18
 *	Remote Request Substitution (RRS)	1
 * Control field:
 *	FD Format indicator (FDF)		1
 *	Reserved bit (res)			1
 *	Bit Rate Switch (BRS)			1
 *	Error Status Indicator (ESI)		1
 *	Data length code (DLC)			4
 *
 * including all fields preceding the data field, ignoring bitstuffing
 */
#define CANFD_FRAME_HEADER_EFF_BITS 41

Annotation

Immediate include surface: `linux/bits.h`, `linux/can.h`, `linux/can/netlink.h`, `linux/math.h`.
Detected declarations: `function can_frame_set_cc_len`, `function canfd_sanitize_len`.
Atlas domain: Core OS / Core Kernel Interface.
Implementation status: source implementation candidate.

Implementation Notes

This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.