fakedhcp.c File Reference

Fake DHCP packets. More...

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <ipxe/settings.h>
#include <ipxe/netdevice.h>
#include <ipxe/dhcppkt.h>
#include <ipxe/fakedhcp.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
static int	copy_encap_settings (struct dhcp_packet *dest, struct settings *source, unsigned int encapsulator)
	Copy settings to DHCP packet.
static int	copy_settings (struct dhcp_packet *dest, struct settings *source)
	Copy settings to DHCP packet.
int	create_fakedhcpdiscover (struct net_device *netdev, void *data, size_t max_len)
	Create fake DHCPDISCOVER packet.
int	create_fakedhcpack (struct net_device *netdev, void *data, size_t max_len)
	Create fake DHCPACK packet.
int	create_fakepxebsack (struct net_device *netdev, void *data, size_t max_len)
	Create fake PXE Boot Server ACK packet.

Detailed Description

Fake DHCP packets.

Definition in file fakedhcp.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

copy_encap_settings()

int copy_encap_settings ( struct dhcp_packet * dest, struct settings * source, unsigned int encapsulator )

static

Copy settings to DHCP packet.

Parameters

dest	Destination DHCP packet
source	Source settings block
encapsulator	Encapsulating setting tag number, or zero

Return values

rc	Return status code

Definition at line 51 of file fakedhcp.c.

                                                             {
        struct setting setting = { .name = "" };
        unsigned int subtag;
        unsigned int tag;
        void *data;
        int 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_raw_setting_copy ( source, &setting, &data);
                        if ( len >= 0 ) {
                                rc = dhcppkt_store ( dest, tag, data, len );
                                free ( data );
                                if ( rc != 0 )
                                        return rc;
                        }
                        break;
                }
        }
 
        return 0;
}

References copy_encap_settings(), data, dest, DHCP_EB_ENCAP, DHCP_ENCAP_OPT, DHCP_MAX_OPTION, DHCP_MIN_OPTION, DHCP_VENDOR_ENCAP, dhcppkt_store(), fetch_raw_setting_copy(), free, len, rc, setting::tag, and tag.

Referenced by copy_encap_settings(), and copy_settings().

copy_settings()

int copy_settings ( struct dhcp_packet * dest, struct settings * source )

static

Copy settings to DHCP packet.

Parameters

dest	Destination DHCP packet
source	Source settings block

Return values

rc	Return status code

Definition at line 95 of file fakedhcp.c.

                                                     {
        return copy_encap_settings ( dest, source, 0 );
}

References copy_encap_settings(), and dest.

Referenced by create_fakedhcpack(), and create_fakepxebsack().

create_fakedhcpdiscover()

int create_fakedhcpdiscover	(	struct net_device *	netdev,
		void *	data,
		size_t	max_len )

Create fake DHCPDISCOVER packet.

Parameters

netdev	Network device
data	Buffer for DHCP packet
max_len	Size of DHCP packet buffer

Return values

rc	Return status code

Used by external code.

Definition at line 110 of file fakedhcp.c.

                                                           {
        struct dhcp_packet dhcppkt;
        struct in_addr ciaddr = { 0 };
        int rc;
 
        if ( ( rc = dhcp_create_request ( &dhcppkt, netdev, DHCPDISCOVER,
                                          dhcp_last_xid, ciaddr, data,
                                          max_len ) ) != 0 ) {
                DBG ( "Could not create DHCPDISCOVER: %s\n",
                      strerror ( rc ) );
                return rc;
        }
 
        return 0;
}

References data, DBG, dhcp_create_request(), dhcp_last_xid, DHCPDISCOVER, netdev, rc, and strerror().

Referenced by efi_pxe_fake_all().

create_fakedhcpack()

int create_fakedhcpack	(	struct net_device *	netdev,
		void *	data,
		size_t	max_len )

Create fake DHCPACK packet.

Parameters

netdev	Network device
data	Buffer for DHCP packet
max_len	Size of DHCP packet buffer

Return values

rc	Return status code

Used by external code.

Definition at line 137 of file fakedhcp.c.

                                                      {
        struct dhcp_packet dhcppkt;
        int rc;
 
        /* Create base DHCPACK packet */
        if ( ( rc = dhcp_create_packet ( &dhcppkt, netdev, DHCPACK,
                                         dhcp_last_xid, 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;
}

References copy_settings(), data, DBG, dhcp_create_packet(), dhcp_last_xid, DHCPACK, netdev, netdev_settings(), NULL, rc, and strerror().

Referenced by create_fakepxebsack(), efi_pxe_fake_all(), and nbi_prepare_dhcp().

create_fakepxebsack()

int create_fakepxebsack	(	struct net_device *	netdev,
		void *	data,
		size_t	max_len )

Create fake PXE Boot Server ACK packet.

Parameters

netdev	Network device
data	Buffer for DHCP packet
max_len	Size of DHCP packet buffer

Return values

rc	Return status code

Used by external code.

Definition at line 179 of file fakedhcp.c.

                                                       {
        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,
                                         dhcp_last_xid, NULL, 0,
                                         data, max_len ) ) != 0 ) {
                DBG ( "Could not create PXE BS ACK: %s\n",
                      strerror ( rc ) );
                return rc;
        }
 
        /* Populate ciaddr */
        fetch_ipv4_setting ( netdev_settings ( netdev ), &ip_setting,
                             &dhcppkt.dhcphdr->ciaddr );
 
        /* 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;
}

References dhcphdr::ciaddr, copy_settings(), create_fakedhcpack(), data, DBG, dhcp_create_packet(), dhcp_last_xid, DHCPACK, dhcp_packet::dhcphdr, fetch_ipv4_setting(), find_settings(), ip_setting, netdev, netdev_settings(), NULL, PROXYDHCP_SETTINGS_NAME, PXEBS_SETTINGS_NAME, rc, and strerror().

Referenced by efi_pxe_fake_all().