acpimac.c File Reference

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>

Go to the source code of this file.

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

Macros
#define	colour   FADT_SIGNATURE
	Colour for debug messages.
#define	AMAC_SIGNATURE   ACPI_SIGNATURE ( 'A', 'M', 'A', 'C' )
	AMAC signature.
#define	MACA_SIGNATURE   ACPI_SIGNATURE ( 'M', 'A', 'C', 'A' )
	MACA signature.
#define	RTMA_SIGNATURE   ACPI_SIGNATURE ( 'R', 'T', 'M', 'A' )
	RTMA signature.
#define	ACPIMAC_MAX_SKIP   8
	Maximum number of bytes to skip after ACPI signature.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
static int	acpimac_decode_base16 (const char *mac, uint8_t *hw_addr)
	Decode Base16-encoded MAC address.
static int	acpimac_decode_raw (const char *mac, uint8_t *hw_addr)
	Decode raw MAC address.
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.
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.
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.
int	acpi_mac (uint8_t *hw_addr)
	Extract MAC address from DSDT/SSDT.
static int	sysmac_fetch (void *data, size_t len)
	Fetch system MAC address setting.
const struct setting sysmac_setting	__setting (SETTING_MISC, sysmac)
	System MAC address setting.

Variables
static struct acpimac_extractor	acpimac_auxmac
	"_AUXMAC_" extraction mechanism
static struct acpimac_extractor	acpimac_rtxmac
	"_RTXMAC_" extraction mechanism
struct builtin_setting sysmac_builtin_setting	__builtin_setting
	System MAC address built-in setting.

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 43 of file acpimac.c.

AMAC_SIGNATURE

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

AMAC signature.

Definition at line 46 of file acpimac.c.

Referenced by acpi_mac().

MACA_SIGNATURE

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

MACA signature.

Definition at line 49 of file acpimac.c.

Referenced by acpi_mac().

RTMA_SIGNATURE

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

RTMA signature.

Definition at line 52 of file acpimac.c.

Referenced by acpi_mac().

ACPIMAC_MAX_SKIP

#define ACPIMAC_MAX_SKIP   8

Maximum number of bytes to skip after ACPI signature.

This is entirely empirical.

Definition at line 58 of file acpimac.c.

Referenced by acpimac_extract().

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

acpimac_decode_base16()

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 82 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()

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 105 of file acpimac.c.

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

References ETH_ALEN, mac, and memcpy().

acpimac_extract()

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 146 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()

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 208 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()

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 223 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 235 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()

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 263 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.

References __setting, builtin_scope, and SETTING_MISC.

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 112 of file acpimac.c.

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

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 119 of file acpimac.c.

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

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 287 of file acpimac.c.

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