/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <gpxe/dhcp.h>
#include <gpxe/nvs.h>
#include <gpxe/nvo.h>
/** @file
*
* Non-volatile stored options
*
*/
/**
* Calculate checksum over non-volatile stored options
*
* @v nvo Non-volatile options block
* @ret sum Checksum
*/
static unsigned int nvo_checksum ( struct nvo_block *nvo ) {
uint8_t *data = nvo->data;
uint8_t sum = 0;
unsigned int i;
for ( i = 0 ; i < nvo->total_len ; i++ ) {
sum += *(data++);
}
return sum;
}
/**
* Load non-volatile stored options from non-volatile storage device
*
* @v nvo Non-volatile options block
* @ret rc Return status code
*/
static int nvo_load ( struct nvo_block *nvo ) {
void *data = nvo->data;
struct nvo_fragment *frag;
int rc;
/* Read data a fragment at a time */
for ( frag = nvo->fragments ; frag->len ; frag++ ) {
if ( ( rc = nvs_read ( nvo->nvs, frag->address, data,
frag->len ) ) != 0 ) {
DBGC ( nvo, "NVO %p could not read %zd bytes at "
"%#04x\n", nvo, frag->len, frag->address );
return rc;
}
data += frag->len;
}
DBGC ( nvo, "NVO %p loaded from non-volatile storage\n", nvo );
return 0;
}
/**
* Save non-volatile stored options back to non-volatile storage device
*
* @v nvo Non-volatile options block
* @ret rc Return status code
*/
static int nvo_save ( struct nvo_block *nvo ) {
void *data = nvo->data;
uint8_t *checksum = data;
struct nvo_fragment *frag;
int rc;
/* Recalculate checksum */
*checksum -= nvo_checksum ( nvo );
/* Write data a fragment at a time */
for ( frag = nvo->fragments ; frag->len ; frag++ ) {
if ( ( rc = nvs_write ( nvo->nvs, frag->address, data,
frag->len ) ) != 0 ) {
DBGC ( nvo, "NVO %p could not write %zd bytes at "
"%#04x\n", nvo, frag->len, frag->address );
return rc;
}
data += frag->len;
}
DBGC ( nvo, "NVO %p saved to non-volatile storage\n", nvo );
return 0;
}
/**
* Parse stored options
*
* @v nvo Non-volatile options block
*
* Verifies that the options data is valid, and configures the DHCP
* options block. If the data is not valid, it is replaced with an
* empty options block.
*/
static void nvo_init_dhcpopts ( struct nvo_block *nvo ) {
uint8_t *options_data;
size_t options_len;
/* Steal one byte for the checksum */
options_data = ( nvo->data + 1 );
options_len = ( nvo->total_len - 1 );
/* If checksum fails, or options data starts with a zero,
* assume the whole block is invalid. This should capture the
* case of random initial contents.
*/
if ( ( nvo_checksum ( nvo ) != 0 ) || ( options_data[0] == 0 ) ) {
DBGC ( nvo, "NVO %p has checksum %02x and initial byte %02x; "
"assuming empty\n", nvo, nvo_checksum ( nvo ),
options_data[0] );
memset ( nvo->data, 0, nvo->total_len );
}
dhcpopt_init ( &nvo->dhcpopts, options_data, options_len );
}
/**
* Store value of NVO setting
*
* @v settings Settings block
* @v setting Setting to store
* @v data Setting data, or NULL to clear setting
* @v len Length of setting data
* @ret rc Return status code
*/
static int nvo_store ( struct settings *settings, struct setting *setting,
const void *data, size_t len ) {
struct nvo_block *nvo =
container_of ( settings, struct nvo_block, settings );
int rc;
/* Update stored options */
if ( ( rc = dhcpopt_store ( &nvo->dhcpopts, setting->tag,
data, len ) ) != 0 ) {
DBGC ( nvo, "NVO %p could not store %zd bytes: %s\n",
nvo, len, strerror ( rc ) );
return rc;
}
/* Save updated options to NVS */
if ( ( rc = nvo_save ( nvo ) ) != 0 )
return rc;
return 0;
}
/**
* Fetch value of NVO setting
*
* @v settings Settings block
* @v setting Setting to fetch
* @v data Buffer to fill with setting data
* @v len Length of buffer
* @ret len Length of setting data, or negative error
*
* The actual length of the setting will be returned even if
* the buffer was too small.
*/
static int nvo_fetch ( struct settings *settings, struct setting *setting,
void *data, size_t len ) {
struct nvo_block *nvo =
container_of ( settings, struct nvo_block, settings );
return dhcpopt_fetch ( &nvo->dhcpopts, setting->tag, data, len );
}
/** NVO settings operations */
static struct settings_operations nvo_settings_operations = {
.store = nvo_store,
.fetch = nvo_fetch,
};
/**
* Initialise non-volatile stored options
*
* @v nvo Non-volatile options block
* @v nvs Underlying non-volatile storage device
* @v fragments List of option-containing fragments
* @v refcnt Containing object reference counter, or NULL
*/
void nvo_init ( struct nvo_block *nvo, struct nvs_device *nvs,
struct nvo_fragment *fragments, struct refcnt *refcnt ) {
nvo->nvs = nvs;
nvo->fragments = fragments;
settings_init ( &nvo->settings, &nvo_settings_operations, refcnt,
"nvo", 0 );
}
/**
* Register non-volatile stored options
*
* @v nvo Non-volatile options block
* @v parent Parent settings block, or NULL
* @ret rc Return status code
*/
int register_nvo ( struct nvo_block *nvo, struct settings *parent ) {
struct nvo_fragment *fragment = nvo->fragments;
int rc;
/* Calculate total length of all fragments */
for ( fragment = nvo->fragments ; fragment->len ; fragment++ )
nvo->total_len += fragment->len;
/* Allocate memory for options and read in from NVS */
nvo->data = malloc ( nvo->total_len );
if ( ! nvo->data ) {
DBGC ( nvo, "NVO %p could not allocate %zd bytes\n",
nvo, nvo->total_len );
rc = -ENOMEM;
goto err_malloc;
}
if ( ( rc = nvo_load ( nvo ) ) != 0 )
goto err_load;
/* Verify and register options */
nvo_init_dhcpopts ( nvo );
if ( ( rc = register_settings ( &nvo->settings, parent ) ) != 0 )
goto err_register;
DBGC ( nvo, "NVO %p registered\n", nvo );
return 0;
err_register:
err_load:
free ( nvo->data );
nvo->data = NULL;
err_malloc:
return rc;
}
/**
* Unregister non-volatile stored options
*
* @v nvo Non-volatile options block
*/
void unregister_nvo ( struct nvo_block *nvo ) {
unregister_settings ( &nvo->settings );
free ( nvo->data );
nvo->data = NULL;
DBGC ( nvo, "NVO %p unregistered\n", nvo );
}
