88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
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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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/** 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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/**
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* @defgroup dhcpopts DHCP option tags
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* @{
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*/
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#define DHCP_PAD 0
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#define DHCP_END 255
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#define DHCP_EB_ENCAP 175
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#define DHCP_EB_PRIORITY DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 1 )
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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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/** 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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};
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#endif /* _GPXE_DHCP_H */
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