/*
 * VMS_RANDOM.H
 *
 * VMS-specific definitions for the FreeBSD random number support via
 * Fortuna.
 *
 * The major purpose of this module is to bridge the set of bits defined
 * in RNDBITDEF.SDL (which are the useful bits controlling the collectors
 * in VMS terms) and the enum random_entropy_source which the FreeBSD C
 * code expects.
 *
 * Author: Doug Gordon
 *
 * Edit History:
 *
 * 	X-1	DAG		Doug Gordon		 1-Feb-2022
 * 		Original.
 */

#ifndef	_VMS_RANDOM_H_
#define	_VMS_RANDOM_H_

/*
 * We want the __NEW_STARLET flavors of our VMS include files but don't
 * want to chance disrupting code that includes this header.
 */

#ifndef __NEW_STARLET
#define __NEW_STARLET
#define __UNDEF_NEW_STARLET
#endif

#include <rndbitdef.h>
#include <types.h>

extern volatile uint64	EXE$GL_ACTIVE_RANDOM_SOURCES;

/*
 * Time between entropy roll-ups from the harvesters
 * One tenth of a second as delta time, in decimal
 */
#define	ONE_TENTH_SEC	1000000LL

/*
 * Fix a stupid problem in RNDBITDEF.H which can be adjusted at a later time
 */
#ifdef RNDBIT$M_PURE_RDRND
#define RNDBIT$M_PURE_RDRAND RNDBIT$M_PURE_RDRND
#define rndbit$v_pure_rdrand rndbit$v_pure_rdrnd
#define RANDOM$K_PURE_RDRAND RANDOM$K_PURE_RDRND
#endif

/*
 * enum of the various source.  Some symbols are retained from the FreeBSD
 * flavor for things that *might* get support.  NI indicates Not Implemented
 * at this point.
 */

enum random_entropy_source {
	RANDOM_START = 0,
	RANDOM_CACHED = RANDOM$K_CACHED,
	/* Environmental sources */
	RANDOM_ATTACH = RANDOM$K_ATTACH,	/* Device attachment - NI */
	RANDOM_PERCPU = RANDOM$K_PERCPU,	/* Per-CPU counters */
	RANDOM_LCKMGR = RANDOM$K_LCKMGR,	/* Lock Manager */
	RANDOM_CLUSTER = RANDOM$K_CLUSTER,	/* Cluster hooks */
	RANDOM_NET_TUN = RANDOM$K_NET_TUN,	/* Write to tunnel - NI */
	RANDOM_NET_ETHER = RANDOM$K_NET_ETHER,	/* Write ethernet packet */
	RANDOM_INTERRUPT = RANDOM$K_INTERRUPT,	/* Device Interrupts */
	RANDOM_SWI = RANDOM$K_SWI,		/* Software Interrupts */
	RANDOM_FS_ATIME = RANDOM$K_FS_ATIME,	/* File System */
	RANDOM_NPP = RANDOM$K_NPP,		/* Pool Packet deallocation */
	RANDOM_UMA = RANDOM_NPP, 		/* Special!! UMA/SLAB Allocator */
	RANDOM_ENVIRONMENTAL_END = RANDOM_UMA,
	/* Fast hardware random-number sources from here on. */
	RANDOM_PURE_START = RANDOM$K_RANDOM_PURE_START,
	RANDOM_PURE_RDRAND = RANDOM$K_PURE_RDRND,	/* X86 RDRAND instruction */
	RANDOM_PURE_VIRTIO = RANDOM$K_PURE_VIRTIO,	/* VIRTIO Entropy driver - NI */
	ENTROPYSOURCE
};

#define	RANDOM_HARVEST_EVERYTHING_MASK ((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1)
#define	RANDOM_HARVEST_PURE_MASK (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START))

/*
 * Random harvest routine prototypes
 */

/* Queued entropy - most common routine */
void exe$random_harvest_queue(const void *entropy, u_int size, enum random_entropy_source origin);

/* Fast harvest - high data rate sources */
void exe$random_harvest_fast(const void *entropy, u_int size);

/* Direct entropy harvesting - copy straight to Fortuna */
void exe$random_harvest_direct(const void *entropy, u_int size, enum random_entropy_source origin);

/*
 * Macros to ease some of the common calls
 */

#define	RANDOM_SOURCE(BIT)	((EXE$GL_ACTIVE_RANDOM_SOURCES & RNDBIT$M_##BIT) != 0)

#define	NPP_ENTROPY_HARVEST(packet, size)	if (RANDOM_SOURCE(NPP)) exe$random_harvest_fast(packet, size)

#ifdef __UNDEF_NEW_STARLET
#undef __NEW_STARLET
#undef __UNDEF_NEW_STARLET
#endif

#endif	/* _VMS_RANDOM_H_ */