/* 
Serval DNA keyring
Copyright (C) 2013-2015 Serval Project Inc.
Copyright (C) 2010-2012 Paul Gardner-Stephen

This program 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 2
of the License, or (at your option) any later version.

This program 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, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#ifndef __SERVAL_DNA__KEYRING_H
#define __SERVAL_DNA__KEYRING_H

#include "lang.h" // for bool_t
#include "serval_types.h" // for sid_t
#include "os.h" // for time_ms_t

struct cli_parsed;
#include "xprintf.h"

enum keyring_keytype {
    KEYTYPE_INVALID = 0,
    KEYTYPE_CRYPTOBOX = 0x01, // must be lowest valid
    KEYTYPE_CRYPTOSIGN = 0x02,
    KEYTYPE_RHIZOME = 0x03,
    // DIDs aren't really keys, but the keyring is a real handy place to keep
    // them, and keep them private if people so desire
    KEYTYPE_DID = 0x04,
    // Arbitrary name/value pairs
    KEYTYPE_PUBLIC_TAG = 0x05,
    // Combined signing / encryption key data
    KEYTYPE_CRYPTOCOMBINED = 0x06,
};

const char *keytype_str(enum keyring_keytype ktype, const char *unknown);

typedef struct keypair {
  enum keyring_keytype type;
  unsigned char *private_key;
  size_t private_key_len;
  unsigned char *public_key;
  size_t public_key_len;
  struct keypair *next;
} keypair;

/* Contains just the list of private:public key pairs and types,
   the pin used to extract them, and the slot in the keyring file
   (so that it can be replaced/rewritten as required). */
#define PKR_SALT_BYTES 32
#define PKR_MAC_BYTES 64
struct keyring_challenge{
  time_ms_t expires;
  unsigned char challenge[24];
};

/* An unlocked identity is represented by an instance of one of these structs
 * in the linked list starting in the keyring_file structure.
 */
typedef struct keyring_identity {
  // A nul-terminated string containing the identity's PIN (passphrase); NULL
  // if no PIN (empty passphrase).  This string must be free()d before the
  // struct is deallocated.
  char *PKRPin;

  // Whether all other identities in the same keyring file that have the same
  // PIN are also unlocked:
  bool_t is_fully_unlocked : 1;

  struct subscriber *subscriber;
  unsigned int slot;
  struct keyring_challenge *challenge;
  const uint8_t *box_sk;
  const sid_t *box_pk;
  const sign_keypair_t *sign_keypair;
  struct keyring_identity *next;
  keypair *keypairs;
} keyring_identity;

#define KEYRING_PAGE_SIZE ((size_t)4096)
#define KEYRING_BAM_BYTES ((size_t)2048)
#define KEYRING_BAM_BITS (KEYRING_BAM_BYTES<<3)
#define KEYRING_SLAB_SIZE (KEYRING_PAGE_SIZE*KEYRING_BAM_BITS)

// should be a power of 2
#define KEYRING_ALLOC_CHUNK (16)

typedef struct keyring_bam {
  size_t file_offset;
  unsigned char allocmap[KEYRING_BAM_BYTES];
  unsigned char loadmap[KEYRING_BAM_BYTES];
  struct keyring_bam *next;
} keyring_bam;

typedef struct keyring_file {
  keyring_bam *bam;
  char *KeyRingPin;
  unsigned char *KeyRingSalt;
  int KeyRingSaltLen;
  keyring_identity *identities;
  FILE *file;
  size_t file_size;
  uint8_t dirty;
} keyring_file;

typedef struct keyring_iterator{
  keyring_file *file;
  keyring_identity *identity;
  keypair *keypair;
} keyring_iterator;

void keyring_iterator_start(keyring_file *k, keyring_iterator *it);
keyring_identity * keyring_next_identity(keyring_iterator *it);
keypair * keyring_next_key(keyring_iterator *it);
keypair * keyring_next_keytype(keyring_iterator *it, enum keyring_keytype keytype);
keypair *keyring_identity_keytype(const keyring_identity *id, enum keyring_keytype keytype);
keypair *keyring_find_did(keyring_iterator *it, const char *did);
keyring_identity *keyring_find_identity_sid(keyring_file *k, const sid_t *sidp);
keyring_identity *keyring_find_identity(keyring_file *k, const identity_t *sign);

void keyring_free(keyring_file *k);
void keyring_release_identities_by_pin(keyring_file *f, const char *pin);
void keyring_release_identity(keyring_file *k, keyring_identity *id);
int keyring_release_subscriber(keyring_file *k, const sid_t *sid);

/* per-thread global handle to keyring file for use in running commands and server */
extern __thread keyring_file *keyring;

/* Public calls to keyring management */
keyring_file *keyring_create_instance();
keyring_file *keyring_open_instance(const char *pin);
keyring_file *keyring_open_instance_cli(const struct cli_parsed *parsed);
unsigned keyring_enter_pin(keyring_file *k, const char *pin);
int keyring_set_did_name(keyring_identity *id, const char *did, const char *name);
int keyring_set_pin(keyring_identity *id, const char *pin);
int keyring_sign_message(struct keyring_identity *identity, unsigned char *content, size_t buffer_len, size_t *content_len);
int keyring_send_identity_request(struct subscriber *subscriber);

int keyring_commit(keyring_file *k);
keyring_identity *keyring_inmemory_identity();
void keyring_free_identity(keyring_identity *id);
keyring_identity *keyring_create_identity(keyring_file *k, const char *pin);
void keyring_destroy_identity(keyring_file *k, keyring_identity *id);
void keyring_identity_extract(const keyring_identity *id, const char **didp, const char **namep);
int keyring_load_from_dump(keyring_file *k, unsigned entry_pinc, const char **entry_pinv, FILE *input);
int keyring_dump(keyring_file *k, XPRINTF xpf, int include_secret);

unsigned char *keyring_get_nm_bytes(const uint8_t *box_sk, const sid_t *box_pk, const sid_t *unknown_sidp);

struct internal_mdp_header;
struct overlay_buffer;
int keyring_send_unlock(struct subscriber *subscriber);
int keyring_release_subscriber(keyring_file *k, const sid_t *sid);

int keyring_set_public_tag(keyring_identity *id, const char *name, const unsigned char *value, size_t length);
keypair * keyring_find_public_tag(keyring_iterator *it, const char *name, const unsigned char **value, size_t *length);
keypair * keyring_find_public_tag_value(keyring_iterator *it, const char *name, const unsigned char *value, size_t length);
int keyring_unpack_tag(const unsigned char *packed, size_t packed_len, const char **name, const unsigned char **value, size_t *length);
int keyring_pack_tag(unsigned char *packed, size_t *packed_len, const char *name, const unsigned char *value, size_t length);

#endif // __SERVAL_DNA__KEYRING_H