ntp.h

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#ifndef _IPXE_NTP_H
#define _IPXE_NTP_H

/** @file
 *
 * Network Time Protocol
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <ipxe/in.h>
#include <ipxe/interface.h>

/** NTP port */
#define NTP_PORT 123

/** An NTP short-format timestamp */
struct ntp_short {
        /** Seconds */
        uint16_t seconds;
        /** Fraction of a second */
        uint16_t fraction;
} __attribute__ (( packed ));

/** An NTP timestamp */
struct ntp_timestamp {
        /** Seconds */
        uint32_t seconds;
        /** Fraction of a second */
        uint32_t fraction;
} __attribute__ (( packed ));

/** An NTP reference identifier */
union ntp_id {
        /** Textual identifier */
        char text[4];
        /** IPv4 address */
        struct in_addr in;
        /** Opaque integer */
        uint32_t opaque;
};

/** An NTP header */
struct ntp_header {
        /** Flags */
        uint8_t flags;
        /** Stratum */
        uint8_t stratum;
        /** Polling rate */
        int8_t poll;
        /** Precision */
        int8_t precision;
        /** Root delay */
        struct ntp_short delay;
        /** Root dispersion */
        struct ntp_short dispersion;
        /** Reference clock identifier */
        union ntp_id id;
        /** Reference timestamp */
        struct ntp_timestamp reference;
        /** Originate timestamp */
        struct ntp_timestamp originate;
        /** Receive timestamp */
        struct ntp_timestamp receive;
        /** Transmit timestamp */
        struct ntp_timestamp transmit;
} __attribute__ (( packed ));

/** Leap second indicator: unknown */
#define NTP_FL_LI_UNKNOWN 0xc0

/** NTP version: 1 */
#define NTP_FL_VN_1 0x20

/** NTP mode: client */
#define NTP_FL_MODE_CLIENT 0x03

/** NTP mode: server */
#define NTP_FL_MODE_SERVER 0x04

/** NTP mode mask */
#define NTP_FL_MODE_MASK 0x07

/** NTP timestamp for start of Unix epoch */
#define NTP_EPOCH 2208988800UL

/** NTP fraction of a second magic value
 *
 * This is a policy decision.
 */
#define NTP_FRACTION_MAGIC 0x69505845UL

/** NTP minimum retransmission timeout
 *
 * This is a policy decision.
 */
#define NTP_MIN_TIMEOUT ( 1 * TICKS_PER_SEC )

/** NTP maximum retransmission timeout
 *
 * This is a policy decision.
 */
#define NTP_MAX_TIMEOUT ( 10 * TICKS_PER_SEC )

extern int start_ntp ( struct interface *job, const char *hostname );

#endif /* _IPXE_NTP_H */