/* tofu.h - TOFU trust model.
 * Copyright (C) 2015 g10 Code GmbH
 *
 * This file is part of GnuPG.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * GnuPG is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#ifndef G10_TOFU_H
#define G10_TOFU_H

#include <config.h>

/* For each binding, we have a trust policy.  */
enum tofu_policy
  {
    /* This value can be returned by tofu_get_policy to indicate that
       there is no policy set for the specified binding.  */
    TOFU_POLICY_NONE = 0,

    /* We made a default policy decision.  This is only done if there
       is no conflict with another binding (that is, the email address
       is not part of another known key).  The default policy is
       configurable (and specified using: --tofu-default-policy).

       Note: when using the default policy, we save TOFU_POLICY_AUTO
       with the binding, not the policy that was in effect.  This way,
       if the user invokes gpg again, but with a different value for
       --tofu-default-policy, a different decision is made.  */
    TOFU_POLICY_AUTO = 1,

    /* The user explicitly marked the binding as good.  In this case,
       we return TRUST_FULLY.  */
    TOFU_POLICY_GOOD = 2,

    /* The user explicitly marked the binding as unknown.  In this
       case, we return TRUST_UNKNOWN.  */
    TOFU_POLICY_UNKNOWN = 3,

    /* The user explicitly marked the binding as bad.  In this case,
       we always return TRUST_NEVER.  */
    TOFU_POLICY_BAD = 4,

    /* The user deferred a definitive policy decision about the
       binding (by selecting accept once or reject once).  The next
       time we see this binding, we should ask the user what to
       do.  */
    TOFU_POLICY_ASK = 5,


    /* Privat evalue used only within tofu.c.  */
    _tofu_GET_POLICY_ERROR = 100
  };


/* Return a string representation of a trust policy.  Returns "???" if
   POLICY is not valid.  */
const char *tofu_policy_str (enum tofu_policy policy);

/* Convert a binding policy (e.g., TOFU_POLICY_BAD) to a trust level
   (e.g., TRUST_BAD) in light of the current configuration.  */
int tofu_policy_to_trust_level (enum tofu_policy policy);

/* Register the binding <PK, USER_ID> and the signature
   described by SIGS_DIGEST and SIG_TIME, which it generated.  Origin
   describes where the signed data came from, e.g., "email:claws"
   (default: "unknown").  If MAY_ASK is 1, then this function may
   interact with the user in the case of a conflict or if the
   binding's policy is ask.  This function returns the binding's trust
   level.  If an error occurs, it returns TRUST_UNKNOWN.  */
int tofu_register (ctrl_t ctrl, PKT_public_key *pk, const char *user_id,
		   const byte *sigs_digest, int sigs_digest_len,
		   time_t sig_time, const char *origin, int may_ask);

/* Combine a trust level returned from the TOFU trust model with a
   trust level returned by the PGP trust model.  This is primarily of
   interest when the trust model is tofu+pgp (TM_TOFU_PGP).  */
int tofu_wot_trust_combine (int tofu, int wot);

/* Determine the validity (TRUST_NEVER, etc.) of the binding
   <PK, USER_ID>.  If MAY_ASK is 1, then this function may
   interact with the user.  If not, TRUST_UNKNOWN is returned.  If an
   error occurs, TRUST_UNDEFINED is returned.  */
int tofu_get_validity (ctrl_t ctrl,
                       PKT_public_key *pk, const char *user_id, int may_ask);

/* Set the policy for all non-revoked user ids in the keyblock KB to
   POLICY.  */
gpg_error_t tofu_set_policy (ctrl_t ctrl, kbnode_t kb, enum tofu_policy policy);

/* Set the TOFU policy for all non-revoked users in the key with the
   key id KEYID to POLICY.  */
gpg_error_t tofu_set_policy_by_keyid (ctrl_t ctrl,
                                      u32 *keyid, enum tofu_policy policy);

/* Return the TOFU policy for the specified binding in *POLICY.  */
gpg_error_t tofu_get_policy (ctrl_t ctrl,
                             PKT_public_key *pk, PKT_user_id *user_id,
			     enum tofu_policy *policy);

/* When doing a lot of DB activities (in particular, when listing
   keys), this causes the DB to enter batch mode, which can
   significantly speed up operations.  */
void tofu_begin_batch_update (void);
void tofu_end_batch_update (void);

/* Release all of the resources associated with a DB meta-handle.  */
void tofu_closedbs (ctrl_t ctrl);

#endif /*G10_TOFU_H*/
