/**
* 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;
}
/**
* Initialise prepopulated block of DHCP options
*
* @v options Uninitialised DHCP option block
* @v data Memory for DHCP option data
* @v alloc_len Length of memory for DHCP option data
* @v realloc DHCP option block reallocator
*
* The memory content must already be filled with valid DHCP options.
* A zeroed block counts as a block of valid DHCP options.
*/
void dhcpopt_init ( struct dhcp_options *options, void *data, size_t alloc_len,
int ( * realloc ) ( struct dhcp_options *options,
size_t len ) ) {
/* Fill in fields */
options->data = data;
options->alloc_len = alloc_len;
options->realloc = realloc;
/* Update length */
dhcpopt_update_used_len ( options );
DBGC ( options, "DHCPOPT %p created (data %p lengths %#zx,%#zx)\n",
options, options->data, options->used_len, options->alloc_len );
}
