diff options
Diffstat (limited to 'src/include/gpxe/dhcp.h')
-rw-r--r-- | src/include/gpxe/dhcp.h | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/src/include/gpxe/dhcp.h b/src/include/gpxe/dhcp.h new file mode 100644 index 00000000..6d293935 --- /dev/null +++ b/src/include/gpxe/dhcp.h @@ -0,0 +1,87 @@ +#ifndef _GPXE_DHCP_H +#define _GPXE_DHCP_H + +/** @file + * + * Dynamic Host Configuration Protocol + * + */ + +#include <stdint.h> +#include <gpxe/list.h> + +/** 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 ) + +/** + * @defgroup dhcpopts DHCP option tags + * @{ + */ + +#define DHCP_PAD 0 +#define DHCP_END 255 + +#define DHCP_EB_ENCAP 175 + +#define DHCP_EB_PRIORITY DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 1 ) + +/** @} */ + +/** + * 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; + uint8_t bytes[0]; + } data; +} __attribute__ (( packed )); + +/** 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; +}; + +#endif /* _GPXE_DHCP_H */ |