Thresholding

This feature is used to reduce the number of logged alerts for noisy rules. This can be tuned to significantly reduce false alarms, and it can also be used to write a newer breed of rules. Thresholding commands limit the number of times a particular event is logged during a specified time interval. More...

Files
file	detect-engine-threshold.c
file	detect-threshold.c
file	util-threshold-config.c

Data Structures
struct	Thresholds
struct	ThresholdEntry_
struct	ThresholdCacheItem
struct	FlowThresholdEntryList_
struct	FlowVarThreshold_

Macros
#define	SID   0
#define	GID   1
#define	REV   2
#define	TRACK   3
#define	TENANT   4
#define	TC_ADDRESS   0
#define	TC_SID   1
#define	TC_GID   2
#define	TC_REV   3
#define	TC_TENANT   4

Typedefs
typedef struct ThresholdEntry_	ThresholdEntry
typedef struct ThresholdCacheItem	ThresholdCacheItem
typedef struct FlowThresholdEntryList_	FlowThresholdEntryList
typedef struct FlowVarThreshold_	FlowVarThreshold

Functions
void	ThresholdInit (void)
void	ThresholdDestroy (void)
uint32_t	ThresholdsExpire (const SCTime_t ts)
	RB_HEAD (THRESHOLD_CACHE, ThresholdCacheItem)
	RB_PROTOTYPE (THRESHOLD_CACHE, ThresholdCacheItem, rb, ThresholdCacheTreeCompareFunc)
	RB_GENERATE (THRESHOLD_CACHE, ThresholdCacheItem, rb, ThresholdCacheTreeCompareFunc)
void	ThresholdCacheThreadFree (void)
const DetectThresholdData *	SigGetThresholdTypeIter (const Signature *sig, const SigMatchData **psm, int list)
	Return next DetectThresholdData for signature. More...
void	FlowThresholdVarFree (void *ptr)
int	PacketAlertThreshold (DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, const DetectThresholdData *td, Packet *p, const Signature *s, PacketAlert *pa)
	Make the threshold logic for signatures. More...

Variables
struct Thresholds	ctx
thread_local uint64_t	cache_lookup_cnt = 0
thread_local uint64_t	cache_lookup_notinit = 0
thread_local uint64_t	cache_lookup_nosupport = 0
thread_local uint64_t	cache_lookup_miss_expired = 0
thread_local uint64_t	cache_lookup_miss = 0
thread_local uint64_t	cache_lookup_hit = 0
thread_local uint64_t	cache_housekeeping_check = 0
thread_local uint64_t	cache_housekeeping_expired = 0
thread_local struct THRESHOLD_CACHE	threshold_cache_tree
thread_local uint64_t	threshold_cache_housekeeping_ts = 0

Detailed Description

This feature is used to reduce the number of logged alerts for noisy rules. This can be tuned to significantly reduce false alarms, and it can also be used to write a newer breed of rules. Thresholding commands limit the number of times a particular event is logged during a specified time interval.

Macro Definition Documentation

GID

#define GID   1

Definition at line 78 of file detect-engine-threshold.c.

REV

#define REV   2

Definition at line 79 of file detect-engine-threshold.c.

SID

#define SID   0

Definition at line 77 of file detect-engine-threshold.c.

TC_ADDRESS

#define TC_ADDRESS   0

Definition at line 239 of file detect-engine-threshold.c.

TC_GID

#define TC_GID   2

Definition at line 241 of file detect-engine-threshold.c.

TC_REV

#define TC_REV   3

Definition at line 242 of file detect-engine-threshold.c.

TC_SID

#define TC_SID   1

Definition at line 240 of file detect-engine-threshold.c.

TC_TENANT

#define TC_TENANT   4

Definition at line 243 of file detect-engine-threshold.c.

TENANT

#define TENANT   4

Definition at line 81 of file detect-engine-threshold.c.

TRACK

#define TRACK   3

Definition at line 80 of file detect-engine-threshold.c.

Typedef Documentation

FlowThresholdEntryList

typedef struct FlowThresholdEntryList_ FlowThresholdEntryList

FlowVarThreshold

typedef struct FlowVarThreshold_ FlowVarThreshold

struct for storing per flow thresholds. This will be stored in the Flow::flowvar list, so it needs to follow the GenericVar header format.

ThresholdCacheItem

typedef struct ThresholdCacheItem ThresholdCacheItem

ThresholdEntry

typedef struct ThresholdEntry_ ThresholdEntry

Function Documentation

FlowThresholdVarFree()

void FlowThresholdVarFree

(

void *

ptr

)

Definition at line 533 of file detect-engine-threshold.c.

Referenced by GenericVarFree().

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PacketAlertThreshold()

int PacketAlertThreshold	(	DetectEngineCtx *	de_ctx,
		DetectEngineThreadCtx *	det_ctx,
		const DetectThresholdData *	td,
		Packet *	p,
		const Signature *	s,
		PacketAlert *	pa
	)

Make the threshold logic for signatures.

Parameters

de_ctx	Detection Context
tsh_ptr	Threshold element
p	Packet structure
s	Signature structure

Return values

2	silent match (no alert but apply actions)
1	alert on this event
0	do not alert on this event

Definition at line 950 of file detect-engine-threshold.c.

References SCEnter, SCReturnInt, DetectThresholdData_::type, and TYPE_SUPPRESS.

RB_GENERATE()

RB_GENERATE	(	THRESHOLD_CACHE	,
		ThresholdCacheItem	,
		rb	,
		ThresholdCacheTreeCompareFunc
	)

RB_HEAD()

RB_HEAD	(	THRESHOLD_CACHE	,
		ThresholdCacheItem
	)

RB_PROTOTYPE()

RB_PROTOTYPE	(	THRESHOLD_CACHE	,
		ThresholdCacheItem	,
		rb	,
		ThresholdCacheTreeCompareFunc
	)

SigGetThresholdTypeIter()

const DetectThresholdData* SigGetThresholdTypeIter	(	const Signature *	sig,
		const SigMatchData **	psm,
		int	list
	)

Return next DetectThresholdData for signature.

Parameters

sig	Signature pointer
psm	Pointer to a Signature Match pointer
list	List to return data from

Return values

tsh	Return the threshold data from signature or NULL if not found

Definition at line 473 of file detect-engine-threshold.c.

ThresholdCacheThreadFree()

void ThresholdCacheThreadFree

(

void

)

Definition at line 454 of file detect-engine-threshold.c.

ThresholdDestroy()

void ThresholdDestroy

(

void

)

Definition at line 71 of file detect-engine-threshold.c.

Referenced by GlobalsDestroy().

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ThresholdInit()

void ThresholdInit

(

void

)

Definition at line 66 of file detect-engine-threshold.c.

ThresholdsExpire()

uint32_t ThresholdsExpire

(

const SCTime_t

ts

)

Definition at line 233 of file detect-engine-threshold.c.

References ctx, Thresholds::thash, THashExpire(), and ts.

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Variable Documentation

cache_housekeeping_check

thread_local uint64_t cache_housekeeping_check = 0

Definition at line 261 of file detect-engine-threshold.c.

cache_housekeeping_expired

thread_local uint64_t cache_housekeeping_expired = 0

Definition at line 262 of file detect-engine-threshold.c.

cache_lookup_cnt

thread_local uint64_t cache_lookup_cnt = 0

Definition at line 255 of file detect-engine-threshold.c.

cache_lookup_hit

thread_local uint64_t cache_lookup_hit = 0

Definition at line 260 of file detect-engine-threshold.c.

cache_lookup_miss

thread_local uint64_t cache_lookup_miss = 0

Definition at line 259 of file detect-engine-threshold.c.

cache_lookup_miss_expired

thread_local uint64_t cache_lookup_miss_expired = 0

Definition at line 258 of file detect-engine-threshold.c.

cache_lookup_nosupport

thread_local uint64_t cache_lookup_nosupport = 0

Definition at line 257 of file detect-engine-threshold.c.

cache_lookup_notinit

thread_local uint64_t cache_lookup_notinit = 0

Definition at line 256 of file detect-engine-threshold.c.

ctx

struct Thresholds ctx

Referenced by AppLayerParserRegisterUnittests(), AppLayerParserStateProtoCleanup(), CreateEveThreadCtx(), DetectBsizeMatch(), DetectBytejumpDoMatch(), DetectBytetestDoMatch(), DetectEngineContentInspection(), DetectEngineContentInspectionBuffer(), DetectFlowbitMatch(), DetectFlowintMatch(), DetectFlowMatch(), DetectFlowvarMatch(), DetectHelperKeywordRegister(), EngineAnalysisRules2(), FreeEveThreadCtx(), OutputJsonBuilderBuffer(), SCACDestroyCtx(), SCACPreparePatterns(), SCACPrintInfo(), SCACSearch(), SCACTilePreparePatterns(), SCACTilePrintInfo(), SCACTileSearchLarge(), SCLuaSbGetContext(), SCProfilingKeywordThreadSetup(), SCProfilingPrefilterThreadSetup(), SCProfilingSghThreadSetup(), SpmDestroyCtx(), SpmScan(), THashCleanup(), THashConsolidateMemcap(), THashExpire(), THashInit(), THashWalk(), ThresholdsExpire(), TmqhOutputFlowFreeCtx(), TmqhOutputFlowHash(), TmqhOutputFlowIPPair(), and TmqhOutputFlowSetupCtx().

threshold_cache_housekeeping_ts

thread_local uint64_t threshold_cache_housekeeping_ts = 0

Definition at line 289 of file detect-engine-threshold.c.

threshold_cache_tree

thread_local struct THRESHOLD_CACHE threshold_cache_tree

Definition at line 288 of file detect-engine-threshold.c.