/*
* Off-the-Record Messaging library
* Copyright (C) 2004-2012 Ian Goldberg, Rob Smits, Chris Alexander,
* Willy Lew, Lisa Du, Nikita Borisov
* <otr@cypherpunks.ca>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of version 2.1 of the GNU Lesser General
* Public License as published by the Free Software Foundation.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __PROTO_H__
#define __PROTO_H__
#include "context.h"
#include "version.h"
#include "tlv.h"
/* If we ever see this sequence in a plaintext message, we'll assume the
* other side speaks OTR, and try to establish a connection. */
#define OTRL_MESSAGE_TAG_BASE " \t \t\t\t\t \t \t \t "
/* The following must each be of length 8 */
#define OTRL_MESSAGE_TAG_V1 " \t \t \t "
#define OTRL_MESSAGE_TAG_V2 " \t\t \t "
#define OTRL_MESSAGE_TAG_V3 " \t\t \t\t"
/* The possible flags contained in a Data Message */
#define OTRL_MSGFLAGS_IGNORE_UNREADABLE 0x01
typedef unsigned int OtrlPolicy;
#define OTRL_POLICY_ALLOW_V1 0x01
#define OTRL_POLICY_ALLOW_V2 0x02
#define OTRL_POLICY_ALLOW_V3 0x04
#define OTRL_POLICY_REQUIRE_ENCRYPTION 0x08
#define OTRL_POLICY_SEND_WHITESPACE_TAG 0x10
#define OTRL_POLICY_WHITESPACE_START_AKE 0x20
#define OTRL_POLICY_ERROR_START_AKE 0x40
#define OTRL_POLICY_VERSION_MASK (OTRL_POLICY_ALLOW_V1 | OTRL_POLICY_ALLOW_V2 |\
OTRL_POLICY_ALLOW_V3)
/* Length of OTR message headers */
#define OTRL_HEADER_LEN 3
#define OTRL_B64_HEADER_LEN 4
/* Analogous to v1 policies */
#define OTRL_POLICY_NEVER 0x00
#define OTRL_POLICY_OPPORTUNISTIC \
( OTRL_POLICY_ALLOW_V2 | \
OTRL_POLICY_ALLOW_V3 | \
OTRL_POLICY_SEND_WHITESPACE_TAG | \
OTRL_POLICY_WHITESPACE_START_AKE | \
OTRL_POLICY_ERROR_START_AKE )
#define OTRL_POLICY_MANUAL \
( OTRL_POLICY_ALLOW_V2 | \
OTRL_POLICY_ALLOW_V3)
#define OTRL_POLICY_ALWAYS \
( OTRL_POLICY_ALLOW_V2 | \
OTRL_POLICY_ALLOW_V3 | \
OTRL_POLICY_REQUIRE_ENCRYPTION | \
OTRL_POLICY_WHITESPACE_START_AKE | \
OTRL_POLICY_ERROR_START_AKE )
#define OTRL_POLICY_DEFAULT OTRL_POLICY_OPPORTUNISTIC
typedef enum {
OTRL_MSGTYPE_NOTOTR,
OTRL_MSGTYPE_TAGGEDPLAINTEXT,
OTRL_MSGTYPE_QUERY,
OTRL_MSGTYPE_DH_COMMIT,
OTRL_MSGTYPE_DH_KEY,
OTRL_MSGTYPE_REVEALSIG,
OTRL_MSGTYPE_SIGNATURE,
OTRL_MSGTYPE_V1_KEYEXCH,
OTRL_MSGTYPE_DATA,
OTRL_MSGTYPE_ERROR,
OTRL_MSGTYPE_UNKNOWN
} OtrlMessageType;
typedef enum {
OTRL_FRAGMENT_UNFRAGMENTED,
OTRL_FRAGMENT_INCOMPLETE,
OTRL_FRAGMENT_COMPLETE
} OtrlFragmentResult;
typedef enum {
OTRL_FRAGMENT_SEND_SKIP, /* Return new message back to caller,
* but don't inject. */
OTRL_FRAGMENT_SEND_ALL,
OTRL_FRAGMENT_SEND_ALL_BUT_FIRST,
OTRL_FRAGMENT_SEND_ALL_BUT_LAST
} OtrlFragmentPolicy;
/* Initialize the OTR library. Pass the version of the API you are
* using. */
gcry_error_t otrl_init(unsigned int ver_major, unsigned int ver_minor,
unsigned int ver_sub);
/* Shortcut */
#define OTRL_INIT do { \
if (otrl_init(OTRL_VERSION_MAJOR, OTRL_VERSION_MINOR, \
OTRL_VERSION_SUB)) { \
exit(1); \
} \
} while(0)
/* Return a pointer to a static string containing the version number of
* the OTR library. */
const char *otrl_version(void);
/* Return a pointer to a newly-allocated OTR query message, customized
* with our name. The caller should free() the result when he's done
* with it. */
char *otrl_proto_default_query_msg(const char *ourname, OtrlPolicy policy);
/* Return the best version of OTR support by both sides, given an OTR
* Query Message and the local policy. */
unsigned int otrl_proto_query_bestversion(const char *querymsg,
OtrlPolicy policy);
/* Locate any whitespace tag in this message, and return the best
* version of OTR support on both sides. Set *starttagp and *endtagp to
* the start and end of the located tag, so that it can be snipped out. */
unsigned int otrl_proto_whitespace_bestversion(const char *msg,
const char **starttagp, const char **endtagp, OtrlPolicy policy);
/* Find the message type. */
OtrlMessageType otrl_proto_message_type(const char *message);
/* Find the message version. */
int otrl_proto_message_version(const char *message);
/* Find the instance tags in this message. */
gcry_error_t otrl_proto_instance(const char *otrmsg,
unsigned int *instance_from, unsigned int *instance_to);
/* Create an OTR Data message. Pass the plaintext as msg, and an
* optional chain of TLVs. A newly-allocated string will be returned in
* *encmessagep. Put the current extra symmetric key into extrakey
* (if non-NULL). */
gcry_error_t otrl_proto_create_data(char **encmessagep, ConnContext *context,
const char *msg, const OtrlTLV *tlvs, unsigned char flags,
unsigned char *extrakey);
/* Extract the flags from an otherwise unreadable Data Message. */
gcry_error_t otrl_proto_data_read_flags(const char *datamsg,
unsigned char *flagsp);
/* Accept an OTR Data Message in datamsg. Decrypt it and put the
* plaintext into *plaintextp, and any TLVs into tlvsp. Put any
* received flags into *flagsp (if non-NULL). Put the current extra
* symmetric key into extrakey (if non-NULL). */
gcry_error_t otrl_proto_accept_data(char **plaintextp, OtrlTLV **tlvsp,
ConnContext *context, const char *datamsg, unsigned char *flagsp,
unsigned char *extrakey);
/* Accumulate a potential fragment into the current context. */
OtrlFragmentResult otrl_proto_fragment_accumulate(char **unfragmessagep,
ConnContext *context, const char *msg);
gcry_error_t otrl_proto_fragment_create(int mms, int fragment_count,
char ***fragments, ConnContext *context, const char *message);
void otrl_proto_fragment_free(char ***fragments, unsigned short arraylen);
#endif
