1 files changed, 125 insertions, 0 deletions
diff --git a/src/tls/tls_session_manager.h b/src/tls/tls_session_manager.h
new file mode 100644
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+++ b/src/tls/tls_session_manager.h
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+/*
+* TLS Session Manager
+* (C) 2011 Jack Lloyd
+*
+* Released under the terms of the Botan license
+*/
+
+#ifndef TLS_SESSION_MANAGER_H__
+#define TLS_SESSION_MANAGER_H__
+
+#include <botan/tls_session.h>
+#include <map>
+
+namespace Botan {
+
+namespace TLS {
+
+/**
+* Session_Manager is an interface to systems which can save
+* session parameters for supporting session resumption.
+*
+* Saving sessions is done on a best-effort basis; an implementation is
+* allowed to drop sessions due to space constraints.
+*
+* Implementations should strive to be thread safe
+*/
+class BOTAN_DLL Session_Manager
+   {
+   public:
+      /**
+      * Try to load a saved session (server side)
+      * @param session_id the session identifier we are trying to resume
+      * @param session will be set to the saved session data (if found),
+               or not modified if not found
+      * @return true if session was modified
+      */
+      virtual bool load_from_session_id(const MemoryRegion<byte>& session_id,
+                                        Session& session) = 0;
+
+      /**
+      * Try to load a saved session (client side)
+      * @param hostname of the host we are connecting to
+      * @param port the port number if we know it, or 0 if unknown
+      * @param session will be set to the saved session data (if found),
+               or not modified if not found
+      * @return true if session was modified
+      */
+      virtual bool load_from_host_info(const std::string& hostname, u16bit port,
+                                       Session& session) = 0;
+
+      /**
+      * Remove this session id from the cache, if it exists
+      */
+      virtual void remove_entry(const MemoryRegion<byte>& session_id) = 0;
+
+      /**
+      * Save a session on a best effort basis; the manager may not in
+      * fact be able to save the session for whatever reason; this is
+      * not an error. Caller cannot assume that calling save followed
+      * immediately by load_from_* will result in a successful lookup.
+      *
+      * @param session to save
+      */
+      virtual void save(const Session& session) = 0;
+
+      /**
+      * Return the allowed lifetime of a session; beyond this time,
+      * sessions are not resumed. Returns 0 if unknown/no explicit
+      * expiration policy.
+      */
+      virtual u32bit session_lifetime() const = 0;
+
+      virtual ~Session_Manager() {}
+   };
+
+/**
+* A simple implementation of Session_Manager that just saves
+* values in memory, with no persistance abilities
+*
+* @todo add locking
+*/
+class BOTAN_DLL Session_Manager_In_Memory : public Session_Manager
+   {
+   public:
+      /**
+      * @param max_sessions a hint on the maximum number of sessions
+      *        to keep in memory at any one time. (If zero, don't cap)
+      * @param session_lifetime sessions are expired after this many
+      *        seconds have elapsed from initial handshake.
+      */
+      Session_Manager_In_Memory(size_t max_sessions = 1000,
+                                u32bit session_lifetime = 7200) :
+         m_max_sessions(max_sessions),
+         m_session_lifetime(session_lifetime)
+            {}
+
+      bool load_from_session_id(const MemoryRegion<byte>& session_id,
+                                Session& session);
+
+      bool load_from_host_info(const std::string& hostname, u16bit port,
+                               Session& session);
+
+      void remove_entry(const MemoryRegion<byte>& session_id);
+
+      void save(const Session& session_data);
+
+      u32bit session_lifetime() const { return m_session_lifetime; }
+
+   private:
+      bool load_from_session_str(const std::string& session_str,
+                                 Session& session);
+
+      size_t m_max_sessions;
+
+      u32bit m_session_lifetime;
+
+      std::map<std::string, Session> m_sessions; // hex(session_id) -> session
+      std::map<std::string, std::string> m_host_sessions;
+   };
+
+}
+
+}
+
+#endif