/**
* 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 ) {
uint8_t *options_data = nvo->dhcpopts.data;
int rc;
/* Skip reading zero-length NVO fields */
if ( nvo->len == 0 ) {
DBGC ( nvo, "NVO %p is empty; skipping load\n", nvo );
return 0;
}
/* Read data */
if ( ( rc = nvs_read ( nvo->nvs, nvo->address, nvo->data,
nvo->len ) ) != 0 ) {
DBGC ( nvo, "NVO %p could not read %zd bytes at %#04x: %s\n",
nvo, nvo->len, nvo->address, strerror ( rc ) );
return rc;
}
/* 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->len );
}
/* Rescan DHCP option block */
dhcpopt_update_used_len ( &nvo->dhcpopts );
DBGC ( nvo, "NVO %p loaded from 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 );
}
/**
* 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 ) {
uint8_t *checksum = nvo->data;
int rc;
/* Recalculate checksum, if applicable */
if ( nvo->len > 0 )
*checksum -= nvo_checksum ( nvo );
/* Write data */
if ( ( rc = nvs_write ( nvo->nvs, nvo->address, nvo->data,
nvo->len ) ) != 0 ) {
DBGC ( nvo, "NVO %p could not write %zd bytes at %#04x: %s\n",
nvo, nvo->len, nvo->address, strerror ( rc ) );
return rc;
}
DBGC ( nvo, "NVO %p saved to 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;
}
