/*      $OpenBSD: dh.h,v 1.15 2021/05/28 18:01:39 tobhe Exp $   */

/*
 * Copyright (c) 2010-2013 Reyk Floeter <reyk@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef DH_GROUP_H
#define DH_GROUP_H

enum group_type {
        GROUP_MODP              = 0,
        GROUP_ECP               = 1,
        GROUP_CURVE25519        = 2,
        GROUP_SNTRUP761X25519   = 3
};

struct group_id {
        enum group_type  type;
        unsigned int     id;
        int              bits;
        char            *prime;
        char            *generator;
        int              nid;
};

struct dh_group {
        int              id;
        const struct group_id
                        *spec;

        void            *dh;
        void            *ec;
        void            *curve25519;
        void            *kemsx;

        int             (*init)(struct dh_group *);
        int             (*getlen)(struct dh_group *);
        int             (*secretlen)(struct dh_group *);
        int             (*exchange)(struct dh_group *, uint8_t *);
        int             (*exchange2)(struct dh_group *, struct ibuf **, struct ibuf *);
        int             (*shared)(struct dh_group *, uint8_t *, uint8_t *);
        int             (*shared2)(struct dh_group *, struct ibuf **, struct ibuf *);
};

#define DH_MAXSZ        1024    /* 8192 bits */

void             group_init(void);
void             group_free(struct dh_group *);
struct dh_group *group_get(uint32_t);
const struct group_id
                *group_getid(uint32_t);

int              dh_create_exchange(struct dh_group *, struct ibuf **, struct ibuf *);
int              dh_create_shared(struct dh_group *, struct ibuf **, struct ibuf *);

#endif /* DH_GROUP_H */