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/*
* 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.
*/
#include <stdint.h>
#include <string.h>
#include <gpxe/dhcp.h>
#include <gpxe/nvs.h>
#include <gpxe/nvo.h>
/** @file
*
* Non-volatile stored options
*
*/
/**
* Calculate total length of non-volatile stored options
*
* @v nvo Non-volatile options block
* @ret total_len Total length of all fragments
*/
static size_t nvo_total_len ( struct nvo_block *nvo ) {
struct nvo_fragment *fragment = nvo->fragments;
size_t total_len = 0;
for ( ; fragment->len ; fragment++ ) {
total_len += fragment->len;
}
return total_len;
}
/**
* Read non-volatile stored options from non-volatile storage device
*
* @v nvo Non-volatile options block
* @ret rc Return status code
*/
static int nvo_read ( struct nvo_block *nvo ) {
struct nvo_fragment *fragment = nvo->fragments;
void *data = nvo->options->data;
int rc;
for ( ; fragment->len ; fragment++ ) {
if ( ( rc = nvs_read ( nvo->nvs, fragment->address,
data, fragment->len ) ) != 0 ) {
DBG ( "NVO %p could not read %zd bytes at %#04x\n",
nvo, fragment->len, fragment->address );
return rc;
}
data += fragment->len;
}
return 0;
}
/**
* Parse stored options
*
* @v nvo Non-volatile options block
* @v total_len Total length of options data
*
* 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_dhcp ( struct nvo_block *nvo, size_t total_len ) {
struct dhcp_option_block *options = nvo->options;
struct dhcp_option *option;
uint8_t sum;
unsigned int i;
/* Steal one byte for the checksum */
options->max_len = ( total_len - 1 );
/* Verify checksum over whole block */
for ( sum = 0, i = 0 ; i < total_len ; i++ ) {
sum += * ( ( uint8_t * ) ( options->data + i ) );
}
if ( sum != 0 ) {
DBG ( "NVO %p has bad checksum %02x; assuming empty\n",
nvo, sum );
goto empty;
}
/* Check that we don't just have a block full of zeroes */
option = options->data;
if ( option->tag == DHCP_PAD ) {
DBG ( "NVO %p has bad start; assuming empty\n", nvo );
goto empty;
}
/* Search for the DHCP_END tag */
options->len = options->max_len;
option = find_dhcp_option ( options, DHCP_END );
if ( ! option ) {
DBG ( "NVO %p has no end tag; assuming empty\n", nvo );
goto empty;
}
/* Set correct length of DHCP options */
options->len = ( ( void * ) option - options->data + 1 );
DBG ( "NVO %p contains %zd bytes of options (maximum %zd)\n",
nvo, options->len, options->max_len );
return;
empty:
/* No options found; initialise an empty options block */
option = options->data;
option->tag = DHCP_END;
options->len = 1;
return;
}
/**
* Register non-volatile stored options
*
* @v nvo Non-volatile options block
* @ret rc Return status code
*/
int nvo_register ( struct nvo_block *nvo ) {
size_t total_len;
int rc;
/* Allocate memory for options and read in from NVS */
total_len = nvo_total_len ( nvo );
nvo->options = alloc_dhcp_options ( total_len );
if ( ! nvo->options ) {
DBG ( "NVO %p could not allocate %zd bytes\n",
nvo, total_len );
rc = -ENOMEM;
goto err;
}
if ( ( rc = nvo_read ( nvo ) ) != 0 )
goto err;
/* Verify and register options */
nvo_init_dhcp ( nvo, total_len );
register_dhcp_options ( nvo->options );
return 0;
err:
free_dhcp_options ( nvo->options );
nvo->options = NULL;
return rc;
}
/**
* Unregister non-volatile stored options
*
* @v nvo Non-volatile options block
*/
void nvo_unregister ( struct nvo_block *nvo ) {
if ( nvo->options ) {
unregister_dhcp_options ( nvo->options );
free_dhcp_options ( nvo->options );
nvo->options = NULL;
}
}
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