/**
* Copy settings to DHCP packet
*
* @v dest Destination DHCP packet
* @v source Source settings block
* @v encapsulator Encapsulating setting tag number, or zero
* @ret rc Return status code
*/
static int copy_encap_settings ( struct dhcp_packet *dest,
struct settings *source,
unsigned int encapsulator ) {
struct setting setting = { .name = "" };
unsigned int subtag;
unsigned int tag;
int len;
int check_len;
int rc;
for ( subtag = DHCP_MIN_OPTION; subtag <= DHCP_MAX_OPTION; subtag++ ) {
tag = DHCP_ENCAP_OPT ( encapsulator, subtag );
switch ( tag ) {
case DHCP_EB_ENCAP:
case DHCP_VENDOR_ENCAP:
/* Process encapsulated settings */
if ( ( rc = copy_encap_settings ( dest, source,
tag ) ) != 0 )
return rc;
break;
default:
/* Copy setting, if present */
setting.tag = tag;
len = fetch_setting_len ( source, &setting );
if ( len < 0 )
break;
{
char buf[len];
check_len = fetch_setting ( source, &setting,
buf, sizeof (buf));
assert ( check_len == len );
if ( ( rc = dhcppkt_store ( dest, tag, buf,
sizeof(buf) )) !=0)
return rc;
}
break;
}
}
return 0;
}
/**
* Copy settings to DHCP packet
*
* @v dest Destination DHCP packet
* @v source Source settings block
* @ret rc Return status code
*/
static int copy_settings ( struct dhcp_packet *dest,
struct settings *source ) {
return copy_encap_settings ( dest, source, 0 );
}
/**
* Create fake DHCPDISCOVER packet
*
* @v netdev Network device
* @v data Buffer for DHCP packet
* @v max_len Size of DHCP packet buffer
* @ret rc Return status code
*
* Used by external code.
*/
int create_fakedhcpdiscover ( struct net_device *netdev,
void *data, size_t max_len ) {
struct dhcp_packet dhcppkt;
struct in_addr ciaddr = { 0 };
int rc;
if ( ( rc = dhcp_create_request ( &dhcppkt, netdev, DHCPDISCOVER,
ciaddr, data, max_len ) ) != 0 ) {
DBG ( "Could not create DHCPDISCOVER: %s\n",
strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Create fake DHCPACK packet
*
* @v netdev Network device
* @v data Buffer for DHCP packet
* @v max_len Size of DHCP packet buffer
* @ret rc Return status code
*
* Used by external code.
*/
int create_fakedhcpack ( struct net_device *netdev,
void *data, size_t max_len ) {
struct dhcp_packet dhcppkt;
int rc;
/* Create base DHCPACK packet */
if ( ( rc = dhcp_create_packet ( &dhcppkt, netdev, DHCPACK, NULL, 0,
data, max_len ) ) != 0 ) {
DBG ( "Could not create DHCPACK: %s\n", strerror ( rc ) );
return rc;
}
/* Merge in globally-scoped settings, then netdev-specific
* settings. Do it in this order so that netdev-specific
* settings take precedence regardless of stated priorities.
*/
if ( ( rc = copy_settings ( &dhcppkt, NULL ) ) != 0 ) {
DBG ( "Could not set DHCPACK global settings: %s\n",
strerror ( rc ) );
return rc;
}
if ( ( rc = copy_settings ( &dhcppkt,
netdev_settings ( netdev ) ) ) != 0 ) {
DBG ( "Could not set DHCPACK netdev settings: %s\n",
strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Create fake PXE Boot Server ACK packet
*
* @v netdev Network device
* @v data Buffer for DHCP packet
* @v max_len Size of DHCP packet buffer
* @ret rc Return status code
*
* Used by external code.
*/
int create_fakepxebsack ( struct net_device *netdev,
void *data, size_t max_len ) {
struct dhcp_packet dhcppkt;
struct settings *proxy_settings;
struct settings *pxebs_settings;
int rc;
/* Identify available settings */
proxy_settings = find_settings ( PROXYDHCP_SETTINGS_NAME );
pxebs_settings = find_settings ( PXEBS_SETTINGS_NAME );
if ( ( ! proxy_settings ) && ( ! pxebs_settings ) ) {
/* No PXE boot server; return the regular DHCPACK */
return create_fakedhcpack ( netdev, data, max_len );
}
/* Create base DHCPACK packet */
if ( ( rc = dhcp_create_packet ( &dhcppkt, netdev, DHCPACK, NULL, 0,
data, max_len ) ) != 0 ) {
DBG ( "Could not create PXE BS ACK: %s\n",
strerror ( rc ) );
return rc;
}
/* Merge in ProxyDHCP options */
if ( proxy_settings &&
( ( rc = copy_settings ( &dhcppkt, proxy_settings ) ) != 0 ) ) {
DBG ( "Could not copy ProxyDHCP settings: %s\n",
strerror ( rc ) );
return rc;
}
/* Merge in BootServerDHCP options, if present */
if ( pxebs_settings &&
( ( rc = copy_settings ( &dhcppkt, pxebs_settings ) ) != 0 ) ) {
DBG ( "Could not copy PXE BS settings: %s\n",
strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Check applicability of DHCP option setting
*
* @v tag Setting tag number
* @ret applies Setting applies to this option block
*/
int dhcpopt_applies ( unsigned int tag ) {
return ( tag && ( tag <= DHCP_ENCAP_OPT ( DHCP_MAX_OPTION,
DHCP_MAX_OPTION ) ) );
}
