From 7649125a9e8412ed716e40f0ff6a40720a211c4b Mon Sep 17 00:00:00 2001
From: Mark Haines <mark.haines@matrix.org>
Date: Wed, 19 Aug 2015 18:16:47 +0100
Subject: [PATCH] Add docstrings for the Session methods
---
include/olm/session.hh | 46 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 44 insertions(+), 2 deletions(-)
diff --git a/include/olm/session.hh b/include/olm/session.hh
index 993a8da..b21b0aa 100644
--- a/include/olm/session.hh
+++ b/include/olm/session.hh
@@ -39,8 +39,13 @@ struct Session {
Curve25519PublicKey alice_base_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();
+ /** 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(
Account const & local_account,
Curve25519PublicKey const & identity_key,
@@ -48,42 +53,79 @@ struct Session {
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(
Account & local_account,
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();
+ /** 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::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(
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();
std::size_t encrypt_message_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();
+ /** 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::uint8_t const * plaintext, std::size_t plaintext_length,
std::uint8_t const * random, std::size_t random_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(
MessageType message_type,
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(
MessageType message_type,
std::uint8_t const * message, std::size_t message_length,
--
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