zeek/src/session/Session.h
2021-09-16 15:35:39 -07:00

294 lines
8.6 KiB
C++

// See the file "COPYING" in the main distribution directory for copyright.
#pragma once
#include <memory>
#include "zeek/EventHandler.h"
#include "zeek/Hash.h"
#include "zeek/Obj.h"
#include "zeek/Timer.h"
#include "zeek/session/Key.h"
namespace zeek
{
class RecordVal;
using RecordValPtr = IntrusivePtr<RecordVal>;
namespace analyzer
{
class Analyzer;
}
namespace session
{
namespace detail
{
class Timer;
}
class Session;
typedef void (Session::*timer_func)(double t);
class Session : public Obj
{
public:
/**
* Construct a new session.
*
* @param t The timestamp for the start and end of the session when it's initially
* created. The end time will be updated as later packets are processed.
* @param timeout_event The event that will be emitted when the session times out.
* @param status_update_event The event that will be emitted for session status
* updates. This can be set to null to disable status updates. This event also
* won't be emitted unless the EnableStatusUpdateTimer() method is called on the
* session, and the interval is set to a non-zero value.
* @param status_update_interval The interval in seconds for the status update
* event to be emitted. Setting this to zero disables the status update timer.
*/
Session(double t, EventHandlerPtr timeout_event, EventHandlerPtr status_update_event = nullptr,
double status_update_interval = 0);
virtual ~Session() { }
/**
* Invoked when the session is about to be removed. Use Ref(this)
* inside Done to keep the session object around, though it'll
* no longer be accessible from the SessionManager.
*/
virtual void Done() = 0;
/**
* Returns a key for the session. This is used as the key for storing
* the session in SessionManager.
*
* @param copy Flag to indicate that the key returned must have a copy of the
* key data instead of just a pointer to it.
*/
virtual detail::Key SessionKey(bool copy) const = 0;
/**
* Set whether this session is in the session table.
*/
void SetInSessionTable(bool in_table) { in_session_table = in_table; }
/**
* Return whether this session is in the session table.
*/
bool IsInSessionTable() const { return in_session_table; }
double StartTime() const { return start_time; }
void SetStartTime(double t) { start_time = t; }
double LastTime() const { return last_time; }
void SetLastTime(double t) { last_time = t; }
// True if we should record subsequent packets (either headers or
// in their entirety, depending on record_contents). We still
// record subsequent SYN/FIN/RST, regardless of how this is set.
bool RecordPackets() const { return record_packets; }
void SetRecordPackets(bool do_record) { record_packets = do_record ? 1 : 0; }
// True if we should record full packets for this session,
// false if we should just record headers.
bool RecordContents() const { return record_contents; }
void SetRecordContents(bool do_record) { record_contents = do_record ? 1 : 0; }
// Set whether to record *current* packet header/full.
void SetRecordCurrentPacket(bool do_record) { record_current_packet = do_record ? 1 : 0; }
void SetRecordCurrentContent(bool do_record) { record_current_content = do_record ? 1 : 0; }
/**
* Returns the associated "session" record.
*/
virtual const RecordValPtr& GetVal() = 0;
[[deprecated("Remove in v5.1. Use GetVal().")]] const RecordValPtr& ConnVal()
{
return GetVal();
}
/**
* Return the memory allocation required by the session record. This requires at
* least one call to Get() first in order to setup the record object.
*/
[[deprecated("Remove in v5.1. MemoryAllocation() is deprecated and will be removed. See "
"GHI-572.")]] virtual unsigned int
MemoryAllocationVal() const = 0;
[[deprecated("Remove in v5.1. Use MemoryAllocationVal().")]] unsigned int
MemoryAllocationConnVal() const
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
return MemoryAllocationVal();
#pragma GCC diagnostic pop
}
/**
* A lower-bound calculation of how much memory a session object is using.
*/
[[deprecated("Remove in v5.1. MemoryAllocation() is deprecated and will be removed. See "
"GHI-572.")]] virtual unsigned int
MemoryAllocation() const;
/**
* Generates session removal event(s). Must be overridden by child classes to
* provide specific removal events.
*/
virtual void RemovalEvent() = 0;
/**
* Generate an event for this session.
*
* @param f The handler for the event to be generated. If the handler doesn't
* exist, this method doesn't generate anything.
* @param analyzer
* @param name If given, this will be passed as the first argument to the
* handler, followed by the session value. If null, then the event's first
* argument is the session value.
*/
void Event(EventHandlerPtr f, analyzer::Analyzer* analyzer = nullptr,
const char* name = nullptr);
/**
* Enqueues an event associated with this session and given analyzer.
*/
void EnqueueEvent(EventHandlerPtr f, analyzer::Analyzer* analyzer, Args args);
/**
* A version of EnqueueEvent() taking a variable number of arguments.
*/
template <class... Args>
std::enable_if_t<std::is_convertible_v<std::tuple_element_t<0, std::tuple<Args...>>, ValPtr>>
EnqueueEvent(EventHandlerPtr h, analyzer::Analyzer* analyzer, Args&&... args)
{
return EnqueueEvent(h, analyzer, zeek::Args{std::forward<Args>(args)...});
}
virtual void Describe(ODesc* d) const override;
/**
* Sets the session to expire after a given amount of time.
*
* @param lifetime The amount of time in seconds from the current network time.
*/
void SetLifetime(double lifetime);
/**
* Sets the inactivity timeout for this session.
*
* @param timeout The number of seconds of inactivity allowed for this session
* before it times out.
*/
void SetInactivityTimeout(double timeout);
/**
* Returns the inactivity timeout for the session.
*/
double InactivityTimeout() const { return inactivity_timeout; }
/**
* Activates the timer for the status update event.
*/
void EnableStatusUpdateTimer();
/**
* Cancels all timers associated with this session.
*/
void CancelTimers();
/**
* Called when the lifetime of the session expires. Fires a timeout event and
* removes the session from the manager.
* TODO: This function has a terrible name considering there's an AddTimer() and
* a RemoveTimer() method in this class as well.
*
* @param t This argument is ignored.
*/
void DeleteTimer(double t);
/**
* Returns a string representation of the transport protocol referenced by the
* session. This is used by SessionManager for statistics.
*/
virtual std::string TransportIdentifier() const = 0;
protected:
friend class detail::Timer;
/**
* Add a given timer to expire at a specific time.
*
* @param timer A pointer to a method that will be called when the timer expires.
* @param t The time when the timer expires. This is an absolute time, not a time
* relative to the current network time.
* @param do_expire If set to true, the timer is also evaluated when Zeek
* terminates.
* @param type The type of timer being added.
*/
void AddTimer(timer_func timer, double t, bool do_expire, zeek::detail::TimerType type);
/**
* Remove a specific timer from firing.
*/
void RemoveTimer(zeek::detail::Timer* t);
/**
* The handler method for inactivity timers.
*/
void InactivityTimer(double t);
/**
* The handler method for status update timers.
*/
void StatusUpdateTimer(double t);
// TODO: is this method used by anyone?
void RemoveConnectionTimer(double t);
double start_time, last_time;
TimerPList timers;
double inactivity_timeout;
EventHandlerPtr session_timeout_event;
EventHandlerPtr session_status_update_event;
double session_status_update_interval;
unsigned int installed_status_timer : 1;
unsigned int timers_canceled : 1;
unsigned int is_active : 1;
unsigned int record_packets : 1, record_contents : 1;
unsigned int record_current_packet : 1, record_current_content : 1;
bool in_session_table;
};
namespace detail
{
class Timer final : public zeek::detail::Timer
{
public:
Timer(Session* arg_session, timer_func arg_timer, double arg_t, bool arg_do_expire,
zeek::detail::TimerType arg_type)
: zeek::detail::Timer(arg_t, arg_type)
{
Init(arg_session, arg_timer, arg_do_expire);
}
~Timer() override;
void Dispatch(double t, bool is_expire) override;
protected:
void Init(Session* session, timer_func timer, bool do_expire);
Session* session;
timer_func timer;
bool do_expire;
};
} // namespace detail
} // namespace session
} // namespace zeek
#define ADD_TIMER(timer, t, do_expire, type) AddTimer(timer_func(timer), (t), (do_expire), (type))