1 files changed, 60 insertions, 0 deletions
diff --git a/libs/libsignal/src/session_builder.h b/libs/libsignal/src/session_builder.h
new file mode 100644
index 0000000000..6e56ba24f0
--- /dev/null
+++ b/libs/libsignal/src/session_builder.h
@@ -0,0 +1,60 @@
+#ifndef SESSION_BUILDER_H
+#define SESSION_BUILDER_H
+
+#include <stdint.h>
+#include "signal_protocol_types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Session builder is responsible for setting up encrypted sessions.
+ * Once a session has been established, session_cipher
+ * can be used to encrypt/decrypt messages in that session.
+ *
+ * Sessions are built from one these different possible vectors:
+ * - A session_pre_key_bundle retrieved from a server
+ * - A pre_key_signal_message received from a client
+ *
+ * Sessions are constructed per Signal Protocol address
+ * (recipient name + device ID tuple). Remote logical users are identified by
+ * their recipient name, and each logical recipient can have multiple
+ * physical devices.
+ */
+
+/**
+ * Constructs a session builder.
+ *
+ * The store and global contexts must remain valid for the lifetime of the
+ * session builder.
+ *
+ * When finished, free the returned instance by calling session_builder_free().
+ *
+ * @param builder set to a freshly allocated session builder instance
+ * @param store the signal_protocol_store_context to store all state information in
+ * @param remote_address the address of the remote user to build a session with
+ * @param global_context the global library context
+ * @return 0 on success, or negative on failure
+ */
+int session_builder_create(session_builder **builder,
+        signal_protocol_store_context *store, const signal_protocol_address *remote_address,
+        signal_context *global_context);
+
+/**
+ * Build a new session from a session_pre_key_bundle retrieved from a server.
+ *
+ * @param bundle A pre key bundle for the destination recipient, retrieved from a server.
+ * @retval SG_SUCCESS Success
+ * @retval SG_ERR_INVALID_KEY when the session_pre_key_bundle is badly formatted.
+ * @retval SG_ERR_UNTRUSTED_IDENTITY when the sender's identity key is not trusted.
+ */
+int session_builder_process_pre_key_bundle(session_builder *builder, session_pre_key_bundle *bundle);
+
+void session_builder_free(session_builder *builder);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SESSION_BUILDER_H */