Commit 7649125a authored by Mark Haines's avatar Mark Haines
Browse files

Add docstrings for the Session methods

parent b3180551
...@@ -39,8 +39,13 @@ struct Session { ...@@ -39,8 +39,13 @@ struct Session {
Curve25519PublicKey alice_base_key; Curve25519PublicKey alice_base_key;
Curve25519PublicKey bob_one_time_key; Curve25519PublicKey bob_one_time_key;
/** The number of random bytes that are needed to create a new outbound
* session. This will be 64 bytes since two ephemeral keys are needed. */
std::size_t new_outbound_session_random_length(); std::size_t new_outbound_session_random_length();
/** Start a new outbound session. Returns std::size_t(-1) on failure. On
* failure last_error will be set with an error code. The last_error will be
* NOT_ENOUGH_RANDOM if the number of random bytes was too small. */
std::size_t new_outbound_session( std::size_t new_outbound_session(
Account const & local_account, Account const & local_account,
Curve25519PublicKey const & identity_key, Curve25519PublicKey const & identity_key,
...@@ -48,42 +53,79 @@ struct Session { ...@@ -48,42 +53,79 @@ struct Session {
std::uint8_t const * random, std::size_t random_length std::uint8_t const * random, std::size_t random_length
); );
/** Start a new inbound session from a pre-key message.
* Returns std::size_t(-1) on failure. On failure last_error will be set
* with an error code. The last_error will be BAD_MESSAGE_FORMAT if
* the message headers could not be decoded. */
std::size_t new_inbound_session( std::size_t new_inbound_session(
Account & local_account, Account & local_account,
Curve25519PublicKey const * their_identity_key, Curve25519PublicKey const * their_identity_key,
std::uint8_t const * one_time_key_message, std::size_t message_length std::uint8_t const * pre_key_message, std::size_t message_length
); );
/** The number of bytes written by session_id() */
std::size_t session_id_length(); std::size_t session_id_length();
/** An identifier for this session. Generated by hashing the public keys
* used to create the session. Returns the length of the session id on
* success or std::size_t(-1) on failure. On failure last_error will be set
* with an error code. The last_error will be OUTPUT_BUFFER_TOO_SMALL if
* the id buffer was too small. */
std::size_t session_id( std::size_t session_id(
std::uint8_t * id, std::size_t id_length std::uint8_t * id, std::size_t id_length
); );
/** True if this session can be used to decode an inbound pre-key message.
* This can be used to test whether a pre-key message should be decoded
* with an existing session or if a new session will need to be created.
* Returns true if the session is the same. Returns false if either the
* session does not match or the pre-key message could not be decoded.
*/
bool matches_inbound_session( bool matches_inbound_session(
Curve25519PublicKey const * their_identity_key, Curve25519PublicKey const * their_identity_key,
std::uint8_t const * one_time_key_message, std::size_t message_length std::uint8_t const * pre_key_message, std::size_t message_length
); );
/** Whether the next message will be a pre-key message or a normal message.
* An outbound session will send pre-key messages until it receives a
* message with a ratchet key. */
MessageType encrypt_message_type(); MessageType encrypt_message_type();
std::size_t encrypt_message_length( std::size_t encrypt_message_length(
std::size_t plaintext_length std::size_t plaintext_length
); );
/** The number of bytes of random data the encrypt method will need to
* encrypt a message. This will be 32 bytes if the session needs to
* generate a new ephemeral key, or will be 0 bytes otherwise. */
std::size_t encrypt_random_length(); std::size_t encrypt_random_length();
/** Encrypt some plain-text. Returns the length of the encrypted message
* or std::size_t(-1) on failure. On failure last_error will be set with
* an error code. The last_error will be NOT_ENOUGH_RANDOM if the number
* of random bytes is too small. The last_error will be
* OUTPUT_BUFFER_TOO_SMALL if the output buffer is too small. */
std::size_t encrypt( std::size_t encrypt(
std::uint8_t const * plaintext, std::size_t plaintext_length, std::uint8_t const * plaintext, std::size_t plaintext_length,
std::uint8_t const * random, std::size_t random_length, std::uint8_t const * random, std::size_t random_length,
std::uint8_t * message, std::size_t message_length std::uint8_t * message, std::size_t message_length
); );
/** An upper bound on the number of bytes of plain-text the decrypt method
* will write for a given input message length. */
std::size_t decrypt_max_plaintext_length( std::size_t decrypt_max_plaintext_length(
MessageType message_type, MessageType message_type,
std::uint8_t const * message, std::size_t message_length std::uint8_t const * message, std::size_t message_length
); );
/** Decrypt a message. Returns the length of the decrypted plain-text or
* std::size_t(-1) on failure. On failure last_error will be set with an
* error code. The last_error will be OUTPUT_BUFFER_TOO_SMALL if the
* plain-text buffer is too small. The last_error will be
* BAD_MESSAGE_VERSION if the message was encrypted with an unsupported
* version of the protocol. The last_error will be BAD_MESSAGE_FORMAT if
* the message headers could not be decoded. The last_error will be
* BAD_MESSAGE_MAC if the message could not be verified */
std::size_t decrypt( std::size_t decrypt(
MessageType message_type, MessageType message_type,
std::uint8_t const * message, std::size_t message_length, std::uint8_t const * message, std::size_t message_length,
......
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