ACPI MAC address. More...

#include <string.h>
#include <errno.h>
#include <ipxe/acpi.h>
#include <ipxe/base16.h>
#include <ipxe/ethernet.h>
#include <ipxe/if_ether.h>
#include <ipxe/settings.h>
#include <ipxe/acpimac.h>

Data Structures
struct	acpimac_extractor
	An ACPI MAC extraction mechanism. More...

Macros
#define	colour FADT_SIGNATURE
	Colour for debug messages. More...

#define	AMAC_SIGNATURE ACPI_SIGNATURE ( 'A', 'M', 'A', 'C' )
	AMAC signature. More...

#define	MACA_SIGNATURE ACPI_SIGNATURE ( 'M', 'A', 'C', 'A' )
	MACA signature. More...

#define	RTMA_SIGNATURE ACPI_SIGNATURE ( 'R', 'T', 'M', 'A' )
	RTMA signature. More...

#define	ACPIMAC_MAX_SKIP 8
	Maximum number of bytes to skip after ACPI signature. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)

static int	acpimac_decode_base16 (const char mac, uint8_t hw_addr)
	Decode Base16-encoded MAC address. More...

static int	acpimac_decode_raw (const char mac, uint8_t hw_addr)
	Decode raw MAC address. More...

static int	acpimac_extract (const struct acpi_header zsdt, size_t len, size_t offset, void data, struct acpimac_extractor *extractor)
	Extract MAC address from DSDT/SSDT. More...

static int	acpimac_extract_auxmac (const struct acpi_header zsdt, size_t len, size_t offset, void data)
	Extract "_AUXMAC_" MAC address from DSDT/SSDT. More...

static int	acpimac_extract_rtxmac (const struct acpi_header zsdt, size_t len, size_t offset, void data)
	Extract "_RTXMAC_" MAC address from DSDT/SSDT. More...

int	acpi_mac (uint8_t *hw_addr)
	Extract MAC address from DSDT/SSDT. More...

static int	sysmac_fetch (void *data, size_t len)
	Fetch system MAC address setting. More...

const struct setting sysmac_setting	__setting (SETTING_MISC, sysmac)
	System MAC address setting. More...

Variables
static struct acpimac_extractor	acpimac_auxmac
	"_AUXMAC_" extraction mechanism More...

static struct acpimac_extractor	acpimac_rtxmac
	"_RTXMAC_" extraction mechanism More...

struct builtin_setting sysmac_builtin_setting	__builtin_setting
	System MAC address built-in setting. More...

Detailed Description

ACPI MAC address.

Definition in file acpimac.c.

Macro Definition Documentation

◆ colour

#define colour FADT_SIGNATURE

Colour for debug messages.

Definition at line 42 of file acpimac.c.

◆ AMAC_SIGNATURE

#define AMAC_SIGNATURE ACPI_SIGNATURE ( 'A', 'M', 'A', 'C' )

AMAC signature.

Definition at line 45 of file acpimac.c.

◆ MACA_SIGNATURE

#define MACA_SIGNATURE ACPI_SIGNATURE ( 'M', 'A', 'C', 'A' )

MACA signature.

Definition at line 48 of file acpimac.c.

◆ RTMA_SIGNATURE

#define RTMA_SIGNATURE ACPI_SIGNATURE ( 'R', 'T', 'M', 'A' )

RTMA signature.

Definition at line 51 of file acpimac.c.

◆ ACPIMAC_MAX_SKIP

#define ACPIMAC_MAX_SKIP 8

Maximum number of bytes to skip after ACPI signature.

This is entirely empirical.

Definition at line 57 of file acpimac.c.

Function Documentation

◆ FILE_LICENCE()

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )

◆ acpimac_decode_base16()

static int acpimac_decode_base16	(	const char *	mac,
		uint8_t *	hw_addr
	)

static

Decode Base16-encoded MAC address.

Parameters

mac	Encoded MAC
hw_addr	MAC address to fill in

Return values

rc	Return status code

Definition at line 81 of file acpimac.c.

                                                                        {
         int len;
         int rc;
 
         /* Attempt to base16-decode MAC address */
         len = base16_decode ( mac, hw_addr, ETH_ALEN );
         if ( len < 0 ) {
                 rc = len;
                 DBGC ( colour, "ACPI could not decode base16 MAC \"%s\": %s\n",
                        mac, strerror ( rc ) );
                 return rc;
         }
 
         return 0;
 }

References colour, DBGC, ETH_ALEN, len, mac, rc, and strerror().

◆ acpimac_decode_raw()

static int acpimac_decode_raw	(	const char *	mac,
		uint8_t *	hw_addr
	)

static

Decode raw MAC address.

Parameters

mac	Encoded MAC
hw_addr	MAC address to fill in

Return values

rc	Return status code

Definition at line 104 of file acpimac.c.

                                                                     {
 
         memcpy ( hw_addr, mac, ETH_ALEN );
         return 0;
 }

References ETH_ALEN, mac, and memcpy().

◆ acpimac_extract()

static int acpimac_extract	(	const struct acpi_header *	zsdt,
		size_t	len,
		size_t	offset,
		void *	data,
		struct acpimac_extractor *	extractor
	)

static

Extract MAC address from DSDT/SSDT.

Parameters

zsdt	DSDT or SSDT
len	Length of DSDT/SSDT
offset	Offset of signature within DSDT/SSDT
data	Data buffer
extractor	ACPI MAC address extractor

Return values

rc	Return status code

Some vendors provide a "system MAC address" within the DSDT/SSDT, to be used to override the MAC address for a USB docking station.

A full implementation would require an ACPI bytecode interpreter, since at least one OEM allows the MAC address to be constructed by executable ACPI bytecode (rather than a fixed data structure).

We instead attempt to extract a plausible-looking "_AUXMAC_#.....#" string that appears shortly after an "AMAC" or "MACA" signature. This should work for most implementations encountered in practice.

Definition at line 145 of file acpimac.c.

                                                                    {
         size_t prefix_len = strlen ( extractor->prefix );
         uint8_t *hw_addr = data;
         size_t skip = 0;
         char buf[ prefix_len + extractor->len + 1 /* "#" */ + 1 /* NUL */ ];
         char *mac = &buf[prefix_len];
         int rc;
 
         /* Skip signature and at least one tag byte */
         offset += ( 4 /* signature */ + 1 /* tag byte */ );
 
         /* Scan for suitable string close to signature */
         for ( skip = 0 ;
               ( ( skip < ACPIMAC_MAX_SKIP ) &&
                 ( offset + skip + sizeof ( buf ) ) <= len ) ;
               skip++ ) {
 
                 /* Read value */
                 memcpy ( buf, ( ( ( const void * ) zsdt ) + offset + skip ),
                          sizeof ( buf ) );
 
                 /* Check for expected format */
                 if ( memcmp ( buf, extractor->prefix, prefix_len ) != 0 )
                         continue;
                 if ( buf[ sizeof ( buf ) - 2 ] != '#' )
                         continue;
                 if ( buf[ sizeof ( buf ) - 1 ] != '\0' )
                         continue;
                 DBGC ( colour, "ACPI found MAC:\n" );
                 DBGC_HDA ( colour, ( offset + skip ), buf, sizeof ( buf ) );
 
                 /* Terminate MAC address string */
                 mac[extractor->len] = '\0';
 
                 /* Decode MAC address */
                 if ( ( rc = extractor->decode ( mac, hw_addr ) ) != 0 )
                         return rc;
 
                 /* Check MAC address validity */
                 if ( ! is_valid_ether_addr ( hw_addr ) ) {
                         DBGC ( colour, "ACPI has invalid MAC %s\n",
                                eth_ntoa ( hw_addr ) );
                         return -EINVAL;
                 }
 
                 return 0;
         }
 
         return -ENOENT;
 }

References ACPIMAC_MAX_SKIP, colour, data, DBGC, DBGC_HDA, acpimac_extractor::decode, EINVAL, ENOENT, eth_ntoa(), is_valid_ether_addr(), acpimac_extractor::len, len, mac, memcmp(), memcpy(), offset, acpimac_extractor::prefix, rc, and strlen().

Referenced by acpimac_extract_auxmac(), and acpimac_extract_rtxmac().

◆ acpimac_extract_auxmac()

static int acpimac_extract_auxmac	(	const struct acpi_header *	zsdt,
		size_t	len,
		size_t	offset,
		void *	data
	)

static

Extract "_AUXMAC_" MAC address from DSDT/SSDT.

Parameters

zsdt	DSDT or SSDT
len	Length of DSDT/SSDT
offset	Offset of signature within DSDT/SSDT
data	Data buffer

Return values

rc	Return status code

Definition at line 207 of file acpimac.c.

                                                                             {
 
         return acpimac_extract ( zsdt, len, offset, data, &acpimac_auxmac );
 }

References acpimac_auxmac, acpimac_extract(), data, len, and offset.

Referenced by acpi_mac().

◆ acpimac_extract_rtxmac()

static int acpimac_extract_rtxmac	(	const struct acpi_header *	zsdt,
		size_t	len,
		size_t	offset,
		void *	data
	)

static

Extract "_RTXMAC_" MAC address from DSDT/SSDT.

Parameters

zsdt	DSDT or SSDT
len	Length of DSDT/SSDT
offset	Offset of signature within DSDT/SSDT
data	Data buffer

Return values

rc	Return status code

Definition at line 222 of file acpimac.c.

                                                                             {
 
         return acpimac_extract ( zsdt, len, offset, data, &acpimac_rtxmac );
 }

References acpimac_extract(), acpimac_rtxmac, data, len, and offset.

Referenced by acpi_mac().

◆ acpi_mac()

int acpi_mac ( uint8_t * hw_addr )

Extract MAC address from DSDT/SSDT.

Parameters

hw_addr MAC address to fill in

Return values

rc	Return status code

Definition at line 234 of file acpimac.c.

                                   {
         int rc;
 
         /* Look for an "AMAC" address */
         if ( ( rc = acpi_extract ( AMAC_SIGNATURE, hw_addr,
                                    acpimac_extract_auxmac ) ) == 0 )
                 return 0;
 
         /* Look for a "MACA" address */
         if ( ( rc = acpi_extract ( MACA_SIGNATURE, hw_addr,
                                    acpimac_extract_auxmac ) ) == 0 )
                 return 0;
 
         /* Look for a "RTMA" address */
         if ( ( rc = acpi_extract ( RTMA_SIGNATURE, hw_addr,
                                    acpimac_extract_rtxmac ) ) == 0 )
                 return 0;
 
         return -ENOENT;
 }

References acpi_extract(), acpimac_extract_auxmac(), acpimac_extract_rtxmac(), AMAC_SIGNATURE, ENOENT, MACA_SIGNATURE, rc, and RTMA_SIGNATURE.

Referenced by ecm_fetch_mac(), sysmac_fetch(), and typeof().

◆ sysmac_fetch()

static int sysmac_fetch	(	void *	data,
		size_t	len
	)

static

Fetch system MAC address setting.

Parameters

data	Buffer to fill with setting data
len	Length of buffer

Return values

len	Length of setting data, or negative error

Definition at line 262 of file acpimac.c.

                                                    {
         uint8_t mac[ETH_ALEN];
         int rc;
 
         /* Try fetching ACPI MAC address */
         if ( ( rc = acpi_mac ( mac ) ) != 0 )
                 return rc;
 
         /* Return MAC address */
         if ( len > sizeof ( mac ) )
                 len = sizeof ( mac );
         memcpy ( data, mac, len );
         return ( sizeof ( mac ) );
 }

References acpi_mac(), data, ETH_ALEN, len, mac, memcpy(), and rc.

◆ __setting()

const struct setting sysmac_setting __setting	(	SETTING_MISC	,
		sysmac
	)

System MAC address setting.

Variable Documentation

◆ acpimac_auxmac

struct acpimac_extractor acpimac_auxmac

static

Initial value:

= {
        .prefix = "_AUXMAC_#",
        .len = ( ETH_ALEN * 2 ),
        .decode = acpimac_decode_base16,
}

"_AUXMAC_" extraction mechanism

Definition at line 111 of file acpimac.c.

Referenced by acpimac_extract_auxmac().

◆ acpimac_rtxmac

struct acpimac_extractor acpimac_rtxmac

static

Initial value:

= {
        .prefix = "_RTXMAC_#",
        .len = ETH_ALEN,
        .decode = acpimac_decode_raw,
}

"_RTXMAC_" extraction mechanism

Definition at line 118 of file acpimac.c.

Referenced by acpimac_extract_rtxmac().

◆ __builtin_setting

struct builtin_setting sysmac_builtin_setting __builtin_setting

Initial value:

= {
        .setting = &sysmac_setting,
        .fetch = sysmac_fetch,
}

System MAC address built-in setting.

Definition at line 286 of file acpimac.c.

Data Structures

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ colour

◆ AMAC_SIGNATURE

◆ MACA_SIGNATURE

◆ RTMA_SIGNATURE

◆ ACPIMAC_MAX_SKIP

Function Documentation

◆ FILE_LICENCE()

◆ acpimac_decode_base16()

◆ acpimac_decode_raw()

◆ acpimac_extract()

◆ acpimac_extract_auxmac()

◆ acpimac_extract_rtxmac()

◆ acpi_mac()

◆ sysmac_fetch()

◆ __setting()

Variable Documentation

◆ acpimac_auxmac

◆ acpimac_rtxmac

◆ __builtin_setting