#ifndef _GPXE_DHCP_H
#define _GPXE_DHCP_H
/** @file
*
* Dynamic Host Configuration Protocol
*
*/
#include <stdint.h>
#include <gpxe/list.h>
#include <gpxe/in.h>
#include <gpxe/udp.h>
#include <gpxe/async.h>
#include <gpxe/retry.h>
/** BOOTP/DHCP server port */
#define BOOTPS_PORT 67
/** BOOTP/DHCP client port */
#define BOOTPC_PORT 68
/** Construct a tag value for an encapsulated option
*
* This tag value can be passed to Etherboot functions when searching
* for DHCP options in order to search for a tag within an
* encapsulated options block.
*/
#define DHCP_ENCAP_OPT( encapsulator, encapsulated ) \
( ( (encapsulator) << 8 ) | (encapsulated) )
/** Extract encapsulating option block tag from encapsulated tag value */
#define DHCP_ENCAPSULATOR( encap_opt ) ( (encap_opt) >> 8 )
/** Extract encapsulated option tag from encapsulated tag value */
#define DHCP_ENCAPSULATED( encap_opt ) ( (encap_opt) & 0xff )
/** Option is encapsulated */
#define DHCP_IS_ENCAP_OPT( opt ) DHCP_ENCAPSULATOR( opt )
/**
* @defgroup dhcpopts DHCP option tags
* @{
*/
/** Padding
*
* This tag does not have a length field; it is always only a single
* byte in length.
*/
#define DHCP_PAD 0
/** Minimum normal DHCP option */
#define DHCP_MIN_OPTION 1
/** Subnet mask */
#define DHCP_SUBNET_MASK 1
/** Routers */
#define DHCP_ROUTERS 3
/** DNS servers */
#define DHCP_DNS_SERVERS 6
/** Host name */
#define DHCP_HOST_NAME 12
/** Domain name */
#define DHCP_DOMAIN_NAME 15
/** Root path */
#define DHCP_ROOT_PATH 17
/** Vendor encapsulated options */
#define DHCP_VENDOR_ENCAP 43
/** Requested IP address */
#define DHCP_REQUESTED_ADDRESS 50
/** Lease time */
#define DHCP_LEASE_TIME 51
/** Option overloading
*
* The value of this option is the bitwise-OR of zero or more
* DHCP_OPTION_OVERLOAD_XXX constants.
*/
#define DHCP_OPTION_OVERLOAD 52
/** The "file" field is overloaded to contain extra DHCP options */
#define DHCP_OPTION_OVERLOAD_FILE 1
/** The "sname" field is overloaded to contain extra DHCP options */
#define DHCP_OPTION_OVERLOAD_SNAME 2
/** DHCP message type */
#define DHCP_MESSAGE_TYPE 53
#define DHCPDISCOVER 1
#define DHCPOFFER 2
#define DHCPREQUEST 3
#define DHCPDECLINE 4
#define DHCPACK 5
#define DHCPNAK 6
#define DHCPRELEASE 7
#define DHCPINFORM 8
/** DHCP server identifier */
#define DHCP_SERVER_IDENTIFIER 54
/** Parameter request list */
#define DHCP_PARAMETER_REQUEST_LIST 55
/** Maximum DHCP message size */
#define DHCP_MAX_MESSAGE_SIZE 57
/** Vendor class identifier */
#define DHCP_VENDOR_CLASS_ID 60
/** TFTP server name
*
* This option replaces the fixed "sname" field, when that field is
* used to contain overloaded options.
*/
#define DHCP_TFTP_SERVER_NAME 66
/** Bootfile name
*
* This option replaces the fixed "file" field, when that field is
* used to contain overloaded options.
*/
#define DHCP_BOOTFILE_NAME 67
/** Etherboot-specific encapsulated options
*
* This encapsulated options field is used to contain all options
* specific to Etherboot (i.e. not assigned by IANA or other standards
* bodies).
*/
#define DHCP_EB_ENCAP 175
/** Priority of this options block
*
* This is a signed 8-bit integer field indicating the priority of
* this block of options. It can be used to specify the relative
* priority of multiple option blocks (e.g. options from non-volatile
* storage versus options from a DHCP server).
*/
#define DHCP_EB_PRIORITY DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 1 )
/** "Your" IP address
*
* This option is used internally to contain the value of the "yiaddr"
* field, in order to provide a consistent approach to storing and
* processing options. It should never be present in a DHCP packet.
*/
#define DHCP_EB_YIADDR DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 2 )
/** "Server" IP address
*
* This option is used internally to contain the value of the "siaddr"
* field, in order to provide a consistent approach to storing and
* processing options. It should never be present in a DHCP packet.
*/
#define DHCP_EB_SIADDR DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 3 )
/** BIOS drive number
*
* This is the drive number for a drive emulated via INT 13. 0x80 is
* the first hard disk, 0x81 is the second hard disk, etc.
*/
#define DHCP_EB_BIOS_DRIVE DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 0xbd )
/** Maximum normal DHCP option */
#define DHCP_MAX_OPTION 254
/** End of options
*
* This tag does not have a length field; it is always only a single
* byte in length.
*/
#define DHCP_END 255
/** @} */
/**
* Count number of arguments to a variadic macro
*
* This rather neat, non-iterative solution is courtesy of Laurent
* Deniau.
*
*/
#define _VA_ARG_COUNT( _1, _2, _3, _4, _5, _6, _7, _8, \
_9, _10, _11, _12, _13, _14, _15, _16, \
_17, _18, _19, _20, _21, _22, _23, _24, \
_25, _26, _27, _28, _29, _30, _31, _32, \
_33, _34, _35, _36, _37, _38, _39, _40, \
_41, _42, _43, _44, _45, _46, _47, _48, \
_49, _50, _51, _52, _53, _54, _55, _56, \
_57, _58, _59, _60, _61, _62, _63, N, ... ) N
#define VA_ARG_COUNT( ... ) \
_VA_ARG_COUNT ( __VA_ARGS__, \
63, 62, 61, 60, 59, 58, 57, 56, \
55, 54, 53, 52, 51, 50, 49, 48, \
47, 46, 45, 44, 43, 42, 41, 40, \
39, 38, 37, 36, 35, 34, 33, 32, \
31, 30, 29, 28, 27, 26, 25, 24, \
23, 22, 21, 20, 19, 18, 17, 16, \
15, 14, 13, 12, 11, 10, 9, 8, \
7, 6, 5, 4, 3, 2, 1, 0 )
/** Construct a DHCP option from a list of bytes */
#define DHCP_OPTION( ... ) VA_ARG_COUNT ( __VA_ARGS__ ), __VA_ARGS__
/** Construct a DHCP option from a list of characters */
#define DHCP_STRING( ... ) DHCP_OPTION ( __VA_ARGS__ )
/** Construct a byte-valued DHCP option */
#define DHCP_BYTE( value ) DHCP_OPTION ( value )
/** Construct a word-valued DHCP option */
#define DHCP_WORD( value ) DHCP_OPTION ( ( ( (value) >> 8 ) & 0xff ), \
( ( (value) >> 0 ) & 0xff ) )
/** Construct a dword-valued DHCP option */
#define DHCP_DWORD( value ) DHCP_OPTION ( ( ( (value) >> 24 ) & 0xff ), \
( ( (value) >> 16 ) & 0xff ), \
( ( (value) >> 8 ) & 0xff ), \
( ( (value) >> 0 ) & 0xff ) )
/** Construct a DHCP encapsulated options field */
#define DHCP_ENCAP( ... ) DHCP_OPTION ( __VA_ARGS__, DHCP_END )
/**
* A DHCP option
*
* DHCP options consist of a mandatory tag, a length field that is
* mandatory for all options except @c DHCP_PAD and @c DHCP_END, and a
* payload.
*/
struct dhcp_option {
/** Tag
*
* Must be a @c DHCP_XXX value.
*/
uint8_t tag;
/** Length
*
* This is the length of the data field (i.e. excluding the
* tag and length fields). For the two tags @c DHCP_PAD and
* @c DHCP_END, the length field is implicitly zero and is
* also missing, i.e. these DHCP options are only a single
* byte in length.
*/
uint8_t len;
/** Option data
*
* Interpretation of the content is entirely dependent upon
* the tag. For fields containing a multi-byte integer, the
* field is defined to be in network-endian order (unless you
* are Intel and feel like violating the spec for fun).
*/
union {
uint8_t byte;
uint16_t word;
uint32_t dword;
struct in_addr in;
uint8_t bytes[0];
char string[0];
} data;
} __attribute__ (( packed ));
/**
* Length of a DHCP option header
*
* The header is the portion excluding the data, i.e. the tag and the
* length.
*/
#define DHCP_OPTION_HEADER_LEN ( offsetof ( struct dhcp_option, data ) )
/** Maximum length for a single DHCP option */
#define DHCP_MAX_LEN 0xff
/** A DHCP options block */
struct dhcp_option_block {
/** List of option blocks */
struct list_head list;
/** Option block raw data */
void *data;
/** Option block length */
size_t len;
/** Option block maximum length */
size_t max_len;
/** Block priority
*
* This is determined at the time of the call to
* register_options() by searching for the @c DHCP_EB_PRIORITY
* option.
*/
signed int priority;
};
/**
* A DHCP header
*
*/
struct dhcphdr {
/** Operation
*
* This must be either @c BOOTP_REQUEST or @c BOOTP_REPLY.
*/
uint8_t op;
/** Hardware address type
*
* This is an ARPHRD_XXX constant. Note that ARPHRD_XXX
* constants are nominally 16 bits wide; this could be
* considered to be a bug in the BOOTP/DHCP specification.
*/
uint8_t htype;
/** Hardware address length */
uint8_t hlen;
/** Number of hops from server */
uint8_t hops;
/** Transaction ID */
uint32_t xid;
/** Seconds since start of acquisition */
uint16_t secs;
/** Flags */
uint16_t flags;
/** "Client" IP address
*
* This is filled in if the client already has an IP address
* assigned and can respond to ARP requests.
*/
struct in_addr ciaddr;
/** "Your" IP address
*
* This is the IP address assigned by the server to the client.
*/
struct in_addr yiaddr;
/** "Server" IP address
*
* This is the IP address of the next server to be used in the
* boot process.
*/
struct in_addr siaddr;
/** "Gateway" IP address
*
* This is the IP address of the DHCP relay agent, if any.
*/
struct in_addr giaddr;
/** Client hardware address */
uint8_t chaddr[16];
/** Server host name (null terminated)
*
* This field may be overridden and contain DHCP options
*/
uint8_t sname[64];
/** Boot file name (null terminated)
*
* This field may be overridden and contain DHCP options
*/
uint8_t file[128];
/** DHCP magic cookie
*
* Must have the value @c DHCP_MAGIC_COOKIE.
*/
uint32_t magic;
/** DHCP options
*
* Variable length; extends to the end of the packet. Minimum
* length (for the sake of sanity) is 1, to allow for a single
* @c DHCP_END tag.
*/
uint8_t options[1];
};
/** Opcode for a request from client to server */
#define BOOTP_REQUEST 1
/** Opcode for a reply from server to client */
#define BOOTP_REPLY 2
/** DHCP magic cookie */
#define DHCP_MAGIC_COOKIE 0x63825363UL
/** DHCP packet option block fill order
*
* This is the order in which option blocks are filled when
* reassembling a DHCP packet. We fill the smallest field ("sname")
* first, to maximise the chances of being able to fit large options
* within fields which are large enough to contain them.
*/
enum dhcp_packet_option_block_fill_order {
OPTS_SNAME = 0,
OPTS_FILE,
OPTS_MAIN,
NUM_OPT_BLOCKS
};
/**
* A DHCP packet
*
*/
struct dhcp_packet {
/** The DHCP packet contents */
struct dhcphdr *dhcphdr;
/** Maximum length of the DHCP packet buffer */
size_t max_len;
/** Used length of the DHCP packet buffer */
size_t len;
/** DHCP option blocks within a DHCP packet
*
* A DHCP packet contains three fields which can be used to
* contain options: the actual "options" field plus the "file"
* and "sname" fields (which can be overloaded to contain
* options).
*/
struct dhcp_option_block options[NUM_OPT_BLOCKS];
};
/** A DHCP session */
struct dhcp_session {
/** UDP connection for this session */
struct udp_connection udp;
/** Network device being configured */
struct net_device *netdev;
/** Options obtained from server */
struct dhcp_option_block *options;
/** State of the session
*
* This is a value for the @c DHCP_MESSAGE_TYPE option
* (e.g. @c DHCPDISCOVER).
*/
int state;
/** Asynchronous operation for this DHCP session */
struct async_operation aop;
/** Retransmission timer */
struct retry_timer timer;
};
extern unsigned long dhcp_num_option ( struct dhcp_option *option );
extern void dhcp_ipv4_option ( struct dhcp_option *option,
struct in_addr *inp );
extern int dhcp_snprintf ( char *buf, size_t size,
struct dhcp_option *option );
extern struct dhcp_option *
find_dhcp_option ( struct dhcp_option_block *options, unsigned int tag );
extern void register_dhcp_options ( struct dhcp_option_block *options );
extern void unregister_dhcp_options ( struct dhcp_option_block *options );
extern void init_dhcp_options ( struct dhcp_option_block *options,
void *data, size_t max_len );
extern struct dhcp_option_block * alloc_dhcp_options ( size_t max_len );
extern void free_dhcp_options ( struct dhcp_option_block *options );
extern struct dhcp_option *
set_dhcp_option ( struct dhcp_option_block *options, unsigned int tag,
const void *data, size_t len );
extern struct dhcp_option * find_global_dhcp_option ( unsigned int tag );
extern unsigned long find_dhcp_num_option ( struct dhcp_option_block *options,
unsigned int tag );
extern unsigned long find_global_dhcp_num_option ( unsigned int tag );
extern void find_dhcp_ipv4_option ( struct dhcp_option_block *options,
unsigned int tag, struct in_addr *inp );
extern void find_global_dhcp_ipv4_option ( unsigned int tag,
struct in_addr *inp );
extern void delete_dhcp_option ( struct dhcp_option_block *options,
unsigned int tag );
extern struct dhcp_option_block dhcp_request_options;
extern int create_dhcp_packet ( struct net_device *netdev, uint8_t msgtype,
void *data, size_t max_len,
struct dhcp_packet *dhcppkt );
extern int copy_dhcp_packet_options ( struct dhcp_packet *dhcppkt,
struct dhcp_option_block *options );
extern struct async_operation * start_dhcp ( struct dhcp_session *dhcp );
#endif /* _GPXE_DHCP_H */
