2006-06-27 19:24:07 +02:00
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#ifndef _GPXE_DHCP_H
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#define _GPXE_DHCP_H
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/** @file
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*
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* Dynamic Host Configuration Protocol
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*
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*/
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#include <stdint.h>
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#include <gpxe/list.h>
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2006-07-15 21:24:55 +02:00
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#include <gpxe/in.h>
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/**
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* A DHCP packet
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*
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*/
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struct dhcp_packet {
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/** Operation
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*
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* This must be either @c BOOTP_REQUEST or @c BOOTP_REPLY.
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*/
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uint8_t op;
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/** Hardware address type
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*
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* This is an ARPHRD_XXX constant.
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*/
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uint8_t htype;
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/** Hardware address length */
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uint8_t hlen;
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/** Number of hops from server */
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uint8_t hops;
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/** Transaction ID */
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uint32_t xid;
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/** Seconds since start of acquisition */
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uint16_t secs;
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/** Flags */
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uint16_t flags;
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/** "Client" IP address
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*
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* This is filled in if the client already has an IP address
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* assigned and can respond to ARP requests.
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*/
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struct in_addr ciaddr;
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/** "Your" IP address
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*
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* This is the IP address assigned by the server to the client.
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*/
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struct in_addr yiaddr;
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/** "Server" IP address
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*
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* This is the IP address of the next server to be used in the
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* boot process.
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*/
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struct in_addr siaddr;
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/** "Gateway" IP address
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*
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* This is the IP address of the DHCP relay agent, if any.
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*/
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struct in_addr giaddr;
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/** Client hardware address */
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uint8_t chaddr[16];
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/** Server host name (null terminated)
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*
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* This field may be overridden and contain DHCP options
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*/
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uint8_t sname[64];
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/** Boot file name (null terminated)
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*
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* This field may be overridden and contain DHCP options
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*/
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uint8_t file[128];
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/** DHCP magic cookie
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*
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* Must have the value @c DHCP_MAGIC_COOKIE.
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*/
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uint32_t magic;
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/** DHCP options
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*
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* Variable length; extends to the end of the packet.
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*/
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uint8_t options[0];
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};
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/** Opcode for a request from client to server */
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#define BOOTP_REQUEST 1
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/** Opcode for a reply from server to client */
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#define BOOTP_REPLY 2
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/** DHCP magic cookie */
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#define DHCP_MAGIC_COOKIE 0x63825363UL
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2006-06-27 19:24:07 +02:00
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/** Construct a tag value for an encapsulated option
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*
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* This tag value can be passed to Etherboot functions when searching
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* for DHCP options in order to search for a tag within an
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* encapsulated options block.
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*/
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#define DHCP_ENCAP_OPT( encapsulator, encapsulated ) \
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( ( (encapsulator) << 8 ) | (encapsulated) )
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/** Extract encapsulating option block tag from encapsulated tag value */
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#define DHCP_ENCAPSULATOR( encap_opt ) ( (encap_opt) >> 8 )
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/** Extract encapsulated option tag from encapsulated tag value */
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#define DHCP_ENCAPSULATED( encap_opt ) ( (encap_opt) & 0xff )
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2006-07-15 21:24:55 +02:00
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/** Option is encapsulated */
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2006-07-13 22:49:04 +02:00
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#define DHCP_IS_ENCAP_OPT( opt ) DHCP_ENCAPSULATOR( opt )
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2006-06-27 19:24:07 +02:00
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/**
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* @defgroup dhcpopts DHCP option tags
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* @{
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*/
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2006-07-15 21:24:55 +02:00
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/** Padding
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*
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* This tag does not have a length field; it is always only a single
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* byte in length.
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*/
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2006-06-27 19:24:07 +02:00
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#define DHCP_PAD 0
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2006-07-15 21:24:55 +02:00
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/** Option overloading
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*
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* The value of this option is the bitwise-OR of zero or more
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* DHCP_OPTION_OVERLOAD_XXX constants.
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*/
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#define DHCP_OPTION_OVERLOAD 52
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/** The "file" field is overloaded to contain extra DHCP options */
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#define DHCP_OPTION_OVERLOAD_FILE 1
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/** The "sname" field is overloaded to contain extra DHCP options */
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#define DHCP_OPTION_OVERLOAD_SNAME 2
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/** TFTP server name
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*
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* This option replaces the fixed "sname" field, when that field is
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* used to contain overloaded options.
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*/
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#define DHCP_TFTP_SERVER_NAME 66
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/** Bootfile name
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*
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* This option replaces the fixed "file" field, when that field is
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* used to contain overloaded options.
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*/
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#define DHCP_BOOTFILE_NAME 67
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/** Etherboot-specific encapsulated options
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*
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* This encapsulated options field is used to contain all options
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* specific to Etherboot (i.e. not assigned by IANA or other standards
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* bodies).
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*/
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2006-06-27 19:24:07 +02:00
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#define DHCP_EB_ENCAP 175
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2006-07-15 21:24:55 +02:00
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/** Priority of this options block
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*
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* This is a signed 8-bit integer field indicating the priority of
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* this block of options. It can be used to specify the relative
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* priority of multiple option blocks (e.g. options from non-volatile
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* storage versus options from a DHCP server).
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*/
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2006-06-27 19:24:07 +02:00
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#define DHCP_EB_PRIORITY DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 1 )
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2006-07-15 21:24:55 +02:00
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/** "Your" IP address
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*
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* This option is used internally to contain the value of the "yiaddr"
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* field, in order to provide a consistent approach to storing and
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* processing options. It should never be present in a DHCP packet.
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*/
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#define DHCP_EB_YIADDR DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 2 )
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/** "Server" IP address
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*
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* This option is used internally to contain the value of the "siaddr"
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* field, in order to provide a consistent approach to storing and
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* processing options. It should never be present in a DHCP packet.
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*/
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#define DHCP_EB_SIADDR DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 3 )
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/** End of options
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*
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* This tag does not have a length field; it is always only a single
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* byte in length.
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*/
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#define DHCP_END 255
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2006-06-27 19:24:07 +02:00
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/** @} */
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/**
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* A DHCP option
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*
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* DHCP options consist of a mandatory tag, a length field that is
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* mandatory for all options except @c DHCP_PAD and @c DHCP_END, and a
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* payload.
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*/
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struct dhcp_option {
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/** Tag
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*
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* Must be a @c DHCP_XXX value.
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*/
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uint8_t tag;
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/** Length
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*
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* This is the length of the data field (i.e. excluding the
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* tag and length fields). For the two tags @c DHCP_PAD and
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* @c DHCP_END, the length field is implicitly zero and is
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* also missing, i.e. these DHCP options are only a single
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* byte in length.
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*/
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uint8_t len;
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/** Option data
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*
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* Interpretation of the content is entirely dependent upon
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* the tag. For fields containing a multi-byte integer, the
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* field is defined to be in network-endian order (unless you
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* are Intel and feel like violating the spec for fun).
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*/
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union {
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uint8_t byte;
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uint16_t word;
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uint32_t dword;
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uint8_t bytes[0];
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} data;
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} __attribute__ (( packed ));
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2006-07-13 22:49:04 +02:00
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/**
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* Length of a DHCP option header
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*
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* The header is the portion excluding the data, i.e. the tag and the
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* length.
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*/
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#define DHCP_OPTION_HEADER_LEN ( offsetof ( struct dhcp_option, data ) )
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/** Maximum length for a single DHCP option */
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#define DHCP_MAX_LEN 0xff
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2006-06-27 19:24:07 +02:00
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/** A DHCP options block */
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struct dhcp_option_block {
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/** List of option blocks */
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struct list_head list;
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/** Option block raw data */
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void *data;
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/** Option block length */
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size_t len;
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/** Option block maximum length */
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size_t max_len;
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/** Block priority
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*
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* This is determined at the time of the call to
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* register_options() by searching for the @c DHCP_EB_PRIORITY
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* option.
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*/
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signed int priority;
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2006-06-27 19:24:07 +02:00
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};
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2006-06-28 15:48:02 +02:00
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extern unsigned long dhcp_num_option ( struct dhcp_option *option );
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2006-07-13 22:49:04 +02:00
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extern struct dhcp_option *
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find_dhcp_option ( struct dhcp_option_block *options, unsigned int tag );
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extern struct dhcp_option * find_global_dhcp_option ( unsigned int tag );
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extern void register_dhcp_options ( struct dhcp_option_block *options );
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extern void unregister_dhcp_options ( struct dhcp_option_block *options );
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extern struct dhcp_option_block * alloc_dhcp_options ( size_t max_len );
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extern void free_dhcp_options ( struct dhcp_option_block *options );
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extern struct dhcp_option *
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set_dhcp_option ( struct dhcp_option_block *options, unsigned int tag,
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const void *data, size_t len );
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2006-06-28 20:59:54 +02:00
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/**
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* Find DHCP numerical option, and return its value
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*
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* @v options DHCP options block
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2006-07-13 22:49:04 +02:00
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* @v tag DHCP option tag to search for
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2006-06-28 20:59:54 +02:00
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* @ret value Numerical value of the option, or 0 if not found
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*
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* This function exists merely as a notational shorthand for a call to
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* find_dhcp_option() followed by a call to dhcp_num_option(). It is
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* not possible to distinguish between the cases "option not found"
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* and "option has a value of zero" using this function; if this
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* matters to you then issue the two constituent calls directly and
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* check that find_dhcp_option() returns a non-NULL value.
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*/
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2006-06-28 15:48:02 +02:00
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static inline unsigned long
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2006-07-13 22:49:04 +02:00
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find_dhcp_num_option ( struct dhcp_option_block *options, unsigned int tag ) {
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return dhcp_num_option ( find_dhcp_option ( options, tag ) );
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}
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/**
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* Find DHCP numerical option, and return its value
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*
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* @v tag DHCP option tag to search for
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* @ret value Numerical value of the option, or 0 if not found
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*
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* This function exists merely as a notational shorthand for a call to
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* find_global_dhcp_option() followed by a call to dhcp_num_option().
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* It is not possible to distinguish between the cases "option not
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* found" and "option has a value of zero" using this function; if
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* this matters to you then issue the two constituent calls directly
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* and check that find_global_dhcp_option() returns a non-NULL value.
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*/
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static inline unsigned long
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find_global_dhcp_num_option ( unsigned int tag ) {
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return dhcp_num_option ( find_global_dhcp_option ( tag ) );
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}
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/**
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* Delete DHCP option
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*
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* @v options DHCP options block
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* @v tag DHCP option tag
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*/
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static inline void delete_dhcp_option ( struct dhcp_option_block *options,
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unsigned int tag ) {
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set_dhcp_option ( options, tag, NULL, 0 );
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2006-06-28 15:48:02 +02:00
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}
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2006-06-27 19:24:07 +02:00
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#endif /* _GPXE_DHCP_H */
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