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/*
* Off-the-Record Messaging library
* Copyright (C) 2004-2014 Ian Goldberg, David Goulet, 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 __MESSAGE_H__
#define __MESSAGE_H__
#define OTR_ERROR_PREFIX "?OTR Error: "
typedef enum {
OTRL_ERRCODE_NONE,
OTRL_ERRCODE_ENCRYPTION_ERROR,
OTRL_ERRCODE_MSG_NOT_IN_PRIVATE,
OTRL_ERRCODE_MSG_UNREADABLE,
OTRL_ERRCODE_MSG_MALFORMED,
} OtrlErrorCode;
/* These define the events used to indicate status of SMP to the UI */
typedef enum {
OTRL_SMPEVENT_NONE,
OTRL_SMPEVENT_ERROR,
OTRL_SMPEVENT_ABORT,
OTRL_SMPEVENT_CHEATED,
OTRL_SMPEVENT_ASK_FOR_ANSWER,
OTRL_SMPEVENT_ASK_FOR_SECRET,
OTRL_SMPEVENT_IN_PROGRESS,
OTRL_SMPEVENT_SUCCESS,
OTRL_SMPEVENT_FAILURE
} OtrlSMPEvent;
/* These define the events used to indicate the messages that need
* to be sent */
typedef enum {
OTRL_MSGEVENT_NONE,
OTRL_MSGEVENT_ENCRYPTION_REQUIRED,
OTRL_MSGEVENT_ENCRYPTION_ERROR,
OTRL_MSGEVENT_CONNECTION_ENDED,
OTRL_MSGEVENT_SETUP_ERROR,
OTRL_MSGEVENT_MSG_REFLECTED,
OTRL_MSGEVENT_MSG_RESENT,
OTRL_MSGEVENT_RCVDMSG_NOT_IN_PRIVATE,
OTRL_MSGEVENT_RCVDMSG_UNREADABLE,
OTRL_MSGEVENT_RCVDMSG_MALFORMED,
OTRL_MSGEVENT_LOG_HEARTBEAT_RCVD,
OTRL_MSGEVENT_LOG_HEARTBEAT_SENT,
OTRL_MSGEVENT_RCVDMSG_GENERAL_ERR,
OTRL_MSGEVENT_RCVDMSG_UNENCRYPTED,
OTRL_MSGEVENT_RCVDMSG_UNRECOGNIZED,
OTRL_MSGEVENT_RCVDMSG_FOR_OTHER_INSTANCE
} OtrlMessageEvent;
typedef enum {
OTRL_NOTIFY_ERROR,
OTRL_NOTIFY_WARNING,
OTRL_NOTIFY_INFO
} OtrlNotifyLevel;
typedef enum {
OTRL_CONVERT_SENDING,
OTRL_CONVERT_RECEIVING
} OtrlConvertType;
typedef struct s_OtrlMessageAppOps {
/* Return the OTR policy for the given context. */
OtrlPolicy (*policy)(void *opdata, ConnContext *context);
/* Create a private key for the given accountname/protocol if
* desired. */
void (*create_privkey)(void *opdata, const char *accountname,
const char *protocol);
/* Report whether you think the given user is online. Return 1 if
* you think he is, 0 if you think he isn't, -1 if you're not sure.
*
* If you return 1, messages such as heartbeats or other
* notifications may be sent to the user, which could result in "not
* logged in" errors if you're wrong. */
int (*is_logged_in)(void *opdata, const char *accountname,
const char *protocol, const char *recipient);
/* Send the given IM to the given recipient from the given
* accountname/protocol. */
void (*inject_message)(void *opdata, const char *accountname,
const char *protocol, const char *recipient, const char *message);
/* When the list of ConnContexts changes (including a change in
* state), this is called so the UI can be updated. */
void (*update_context_list)(void *opdata);
/* A new fingerprint for the given user has been received. */
void (*new_fingerprint)(void *opdata, OtrlUserState us,
const char *accountname, const char *protocol,
const char *username, unsigned char fingerprint[20]);
/* The list of known fingerprints has changed. Write them to disk. */
void (*write_fingerprints)(void *opdata);
/* A ConnContext has entered a secure state. */
void (*gone_secure)(void *opdata, ConnContext *context);
/* A ConnContext has left a secure state. */
void (*gone_insecure)(void *opdata, ConnContext *context);
/* We have completed an authentication, using the D-H keys we
* already knew. is_reply indicates whether we initiated the AKE. */
void (*still_secure)(void *opdata, ConnContext *context, int is_reply);
/* Find the maximum message size supported by this protocol. */
int (*max_message_size)(void *opdata, ConnContext *context);
/* Return a newly allocated string containing a human-friendly
* representation for the given account */
const char *(*account_name)(void *opdata, const char *account,
const char *protocol);
/* Deallocate a string returned by account_name */
void (*account_name_free)(void *opdata, const char *account_name);
/* We received a request from the buddy to use the current "extra"
* symmetric key. The key will be passed in symkey, of length
* OTRL_EXTRAKEY_BYTES. The requested use, as well as use-specific
* data will be passed so that the applications can communicate other
* information (some id for the data transfer, for example). */
void (*received_symkey)(void *opdata, ConnContext *context,
unsigned int use, const unsigned char *usedata,
size_t usedatalen, const unsigned char *symkey);
/* Return a string according to the error event. This string will then
* be concatenated to an OTR header to produce an OTR protocol error
* message. The following are the possible error events:
* - OTRL_ERRCODE_ENCRYPTION_ERROR
* occured while encrypting a message
* - OTRL_ERRCODE_MSG_NOT_IN_PRIVATE
* sent encrypted message to somebody who is not in
* a mutual OTR session
* - OTRL_ERRCODE_MSG_UNREADABLE
* sent an unreadable encrypted message
* - OTRL_ERRCODE_MSG_MALFORMED
* message sent is malformed */
const char *(*otr_error_message)(void *opdata, ConnContext *context,
OtrlErrorCode err_code);
/* Deallocate a string returned by otr_error_message */
void (*otr_error_message_free)(void *opdata, const char *err_msg);
/* Return a string that will be prefixed to any resent message. If this
* function is not provided by the application then the default prefix,
* "[resent]", will be used.
* */
const char *(*resent_msg_prefix)(void *opdata, ConnContext *context);
/* Deallocate a string returned by resent_msg_prefix */
void (*resent_msg_prefix_free)(void *opdata, const char *prefix);
/* Update the authentication UI with respect to SMP events
* These are the possible events:
* - OTRL_SMPEVENT_ASK_FOR_SECRET
* prompt the user to enter a shared secret. The sender application
* should call otrl_message_initiate_smp, passing NULL as the question.
* When the receiver application resumes the SM protocol by calling
* otrl_message_respond_smp with the secret answer.
* - OTRL_SMPEVENT_ASK_FOR_ANSWER
* (same as OTRL_SMPEVENT_ASK_FOR_SECRET but sender calls
* otrl_message_initiate_smp_q instead)
* - OTRL_SMPEVENT_CHEATED
* abort the current auth and update the auth progress dialog
* with progress_percent. otrl_message_abort_smp should be called to
* stop the SM protocol.
* - OTRL_SMPEVENT_INPROGRESS and
* OTRL_SMPEVENT_SUCCESS and
* OTRL_SMPEVENT_FAILURE and
* OTRL_SMPEVENT_ABORT
* update the auth progress dialog with progress_percent
* - OTRL_SMPEVENT_ERROR
* (same as OTRL_SMPEVENT_CHEATED)
* */
void (*handle_smp_event)(void *opdata, OtrlSMPEvent smp_event,
ConnContext *context, unsigned short progress_percent,
char *question);
/* Handle and send the appropriate message(s) to the sender/recipient
* depending on the message events. All the events only require an opdata,
* the event, and the context. The message and err will be NULL except for
* some events (see below). The possible events are:
* - OTRL_MSGEVENT_ENCRYPTION_REQUIRED
* Our policy requires encryption but we are trying to send
* an unencrypted message out.
* - OTRL_MSGEVENT_ENCRYPTION_ERROR
* An error occured while encrypting a message and the message
* was not sent.
* - OTRL_MSGEVENT_CONNECTION_ENDED
* Message has not been sent because our buddy has ended the
* private conversation. We should either close the connection,
* or refresh it.
* - OTRL_MSGEVENT_SETUP_ERROR
* A private conversation could not be set up. A gcry_error_t
* will be passed.
* - OTRL_MSGEVENT_MSG_REFLECTED
* Received our own OTR messages.
* - OTRL_MSGEVENT_MSG_RESENT
* The previous message was resent.
* - OTRL_MSGEVENT_RCVDMSG_NOT_IN_PRIVATE
* Received an encrypted message but cannot read
* it because no private connection is established yet.
* - OTRL_MSGEVENT_RCVDMSG_UNREADABLE
* Cannot read the received message.
* - OTRL_MSGEVENT_RCVDMSG_MALFORMED
* The message received contains malformed data.
* - OTRL_MSGEVENT_LOG_HEARTBEAT_RCVD
* Received a heartbeat.
* - OTRL_MSGEVENT_LOG_HEARTBEAT_SENT
* Sent a heartbeat.
* - OTRL_MSGEVENT_RCVDMSG_GENERAL_ERR
* Received a general OTR error. The argument 'message' will
* also be passed and it will contain the OTR error message.
* - OTRL_MSGEVENT_RCVDMSG_UNENCRYPTED
* Received an unencrypted message. The argument 'message' will
* also be passed and it will contain the plaintext message.
* - OTRL_MSGEVENT_RCVDMSG_UNRECOGNIZED
* Cannot recognize the type of OTR message received.
* - OTRL_MSGEVENT_RCVDMSG_FOR_OTHER_INSTANCE
* Received and discarded a message intended for another instance. */
void (*handle_msg_event)(void *opdata, OtrlMessageEvent msg_event,
ConnContext *context, const char *message,
gcry_error_t err);
/* Create a instance tag for the given accountname/protocol if
* desired. */
void (*create_instag)(void *opdata, const char *accountname,
const char *protocol);
/* Called immediately before a data message is encrypted, and after a data
* message is decrypted. The OtrlConvertType parameter has the value
* OTRL_CONVERT_SENDING or OTRL_CONVERT_RECEIVING to differentiate these
* cases. */
void (*convert_msg)(void *opdata, ConnContext *context,
OtrlConvertType convert_type, char ** dest, const char *src);
/* Deallocate a string returned by convert_msg. */
void (*convert_free)(void *opdata, ConnContext *context, char *dest);
/* When timer_control is called, turn off any existing periodic
* timer.
*
* Additionally, if interval > 0, set a new periodic timer
* to go off every interval seconds. When that timer fires, you
* must call otrl_message_poll(userstate, uiops, uiopdata); from the
* main libotr thread.
*
* The timing does not have to be exact; this timer is used to
* provide forward secrecy by cleaning up stale private state that
* may otherwise stick around in memory. Note that the
* timer_control callback may be invoked from otrl_message_poll
* itself, possibly to indicate that interval == 0 (that is, that
* there's no more periodic work to be done at this time).
*
* If you set this callback to NULL, then you must ensure that your
* application calls otrl_message_poll(userstate, uiops, uiopdata);
* from the main libotr thread every definterval seconds (where
* definterval can be obtained by calling
* definterval = otrl_message_poll_get_default_interval(userstate);
* right after creating the userstate). The advantage of
* implementing the timer_control callback is that the timer can be
* turned on by libotr only when it's needed.
*
* It is not a problem (except for a minor performance hit) to call
* otrl_message_poll more often than requested, whether
* timer_control is implemented or not.
*
* If you fail to implement the timer_control callback, and also
* fail to periodically call otrl_message_poll, then you open your
* users to a possible forward secrecy violation: an attacker that
* compromises the user's computer may be able to decrypt a handful
* of long-past messages (the first messages of an OTR
* conversation).
*/
void (*timer_control)(void *opdata, unsigned int interval);
} OtrlMessageAppOps;
/* Deallocate a message allocated by other otrl_message_* routines. */
void otrl_message_free(char *message);
/* Handle a message about to be sent to the network. It is safe to pass
* all messages about to be sent to this routine. add_appdata is a
* function that will be called in the event that a new ConnContext is
* created. It will be passed the data that you supplied, as well as a
* pointer to the new ConnContext. You can use this to add
* application-specific information to the ConnContext using the
* "context->app" field, for example. If you don't need to do this, you
* can pass NULL for the last two arguments of otrl_message_sending.
*
* tlvs is a chain of OtrlTLVs to append to the private message. It is
* usually correct to just pass NULL here.
*
* If non-NULL, ops->convert_msg will be called just before encrypting a
* message.
*
* "instag" specifies the instance tag of the buddy (protocol version 3 only).
* Meta-instances may also be specified (e.g., OTRL_INSTAG_MOST_SECURE).
* If "contextp" is not NULL, it will be set to the ConnContext used for
* sending the message.
*
* If no fragmentation or msg injection is wanted, use OTRL_FRAGMENT_SEND_SKIP
* as the OtrlFragmentPolicy. In this case, this function will assign *messagep
* with the encrypted msg. If the routine returns non-zero, then the library
* tried to encrypt the message, but for some reason failed. DO NOT send the
* message in the clear in that case. If *messagep gets set by the call to
* something non-NULL, then you should replace your message with the contents
* of *messagep, and send that instead.
*
* Other fragmentation policies are OTRL_FRAGMENT_SEND_ALL,
* OTRL_FRAGMENT_SEND_ALL_BUT_LAST, or OTRL_FRAGMENT_SEND_ALL_BUT_FIRST. In
* these cases, the appropriate fragments will be automatically sent. For the
* last two policies, the remaining fragment will be passed in *original_msg.
*
* Call otrl_message_free(*messagep) if you don't need *messagep or when you're
* done with it. */
gcry_error_t otrl_message_sending(OtrlUserState us,
const OtrlMessageAppOps *ops,
void *opdata, const char *accountname, const char *protocol,
const char *recipient, otrl_instag_t instag, const char *original_msg,
OtrlTLV *tlvs, char **messagep, OtrlFragmentPolicy fragPolicy,
ConnContext **contextp,
void (*add_appdata)(void *data, ConnContext *context),
void *data);
/* Handle a message just received from the network. It is safe to pass
* all received messages to this routine. add_appdata is a function
* that will be called in the event that a new ConnContext is created.
* It will be passed the data that you supplied, as well as
* a pointer to the new ConnContext. You can use this to add
* application-specific information to the ConnContext using the
* "context->app" field, for example. If you don't need to do this, you
* can pass NULL for the last two arguments of otrl_message_receiving.
*
* If non-NULL, ops->convert_msg will be called after a data message is
* decrypted.
*
* If "contextp" is not NULL, it will be set to the ConnContext used for
* receiving the message.
*
* If otrl_message_receiving returns 1, then the message you received
* was an internal protocol message, and no message should be delivered
* to the user.
*
* If it returns 0, then check if *messagep was set to non-NULL. If
* so, replace the received message with the contents of *messagep, and
* deliver that to the user instead. You must call
* otrl_message_free(*messagep) when you're done with it. If tlvsp is
* non-NULL, *tlvsp will be set to a chain of any TLVs that were
* transmitted along with this message. You must call
* otrl_tlv_free(*tlvsp) when you're done with those.
*
* If otrl_message_receiving returns 0 and *messagep is NULL, then this
* was an ordinary, non-OTR message, which should just be delivered to
* the user without modification. */
int otrl_message_receiving(OtrlUserState us, const OtrlMessageAppOps *ops,
void *opdata, const char *accountname, const char *protocol,
const char *sender, const char *message, char **newmessagep,
OtrlTLV **tlvsp, ConnContext **contextp,
void (*add_appdata)(void *data, ConnContext *context),
void *data);
/* Put a connection into the PLAINTEXT state, first sending the
* other side a notice that we're doing so if we're currently ENCRYPTED,
* and we think he's logged in. Affects only the specified instance. */
void otrl_message_disconnect(OtrlUserState us, const OtrlMessageAppOps *ops,
void *opdata, const char *accountname, const char *protocol,
const char *username, otrl_instag_t instance);
/* Put a connection into the PLAINTEXT state, first sending the
* other side a notice that we're doing so if we're currently ENCRYPTED,
* and we think he's logged in. Affects all matching instances. */
void otrl_message_disconnect_all_instances(OtrlUserState us,
const OtrlMessageAppOps *ops, void *opdata, const char *accountname,
const char *protocol, const char *username);
/* Initiate the Socialist Millionaires' Protocol */
void otrl_message_initiate_smp(OtrlUserState us, const OtrlMessageAppOps *ops,
void *opdata, ConnContext *context, const unsigned char *secret,
size_t secretlen);
/* Initiate the Socialist Millionaires' Protocol and send a prompt
* question to the buddy */
void otrl_message_initiate_smp_q(OtrlUserState us,
const OtrlMessageAppOps *ops, void *opdata, ConnContext *context,
const char *question, const unsigned char *secret, size_t secretlen);
/* Respond to a buddy initiating the Socialist Millionaires' Protocol */
void otrl_message_respond_smp(OtrlUserState us, const OtrlMessageAppOps *ops,
void *opdata, ConnContext *context, const unsigned char *secret,
size_t secretlen);
/* Abort the SMP. Called when an unexpected SMP message breaks the
* normal flow. */
void otrl_message_abort_smp(OtrlUserState us, const OtrlMessageAppOps *ops,
void *opdata, ConnContext *context);
/* Get the current extra symmetric key (of size OTRL_EXTRAKEY_BYTES
* bytes) and let the other side know what we're going to use it for.
* The key is stored in symkey, which must already be allocated
* and OTRL_EXTRAKEY_BYTES bytes long. */
gcry_error_t otrl_message_symkey(OtrlUserState us,
const OtrlMessageAppOps *ops, void *opdata, ConnContext *context,
unsigned int use, const unsigned char *usedata, size_t usedatalen,
unsigned char *symkey);
/* If you do _not_ define a timer_control callback function, set a timer
* to go off every definterval =
* otrl_message_poll_get_default_interval(userstate) seconds, and call
* otrl_message_poll every time the timer goes off. */
unsigned int otrl_message_poll_get_default_interval(OtrlUserState us);
/* Call this function every so often, either as directed by the
* timer_control callback, or every definterval =
* otrl_message_poll_get_default_interval(userstate) seconds if you have
* no timer_control callback. This function must be called from the
* main libotr thread.*/
void otrl_message_poll(OtrlUserState us, const OtrlMessageAppOps *ops,
void *opdata);
#endif