Add generic samplers

Author: phaag

README.md

@@ -68,6 +68,11 @@ func main() {
 			fmt.Printf("Record %d has no IPs\n", cnt)
 		}
 
+		// sampling
+ 		packetInterval, spaceInterval := record.SamplerInfo(nffile)
+		fmt.Printf("Record sampler info: packet interval: %d, space interval: %d\n",
+               packetInterval, spaceInterval)
+    
 		// print the entire record using %v
 		fmt.Printf("%v\n", record)
 

defs.go

@@ -74,3 +74,4 @@ type EXipReceived struct {
 }
 
 type ExporterInfoRecord C.struct_exporter_info_record_s
+type SamplerRecord C.struct_sampler_record_s

example/reader/main.go

@@ -58,6 +58,10 @@ func main() {
 			fmt.Printf("Record %d has no IPs\n", cnt)
 		}
 
+		// sampling
+		packetInterval, spaceInterval := record.SamplerInfo(nffile)
+		fmt.Printf("Record sampler info: packet interval: %d, space interval: %d\n", packetInterval, spaceInterval)
+
 		// print the entire record using %v
 		fmt.Printf("%v\n", record)
 
@@ -99,6 +103,10 @@ func main() {
 		if exporter.IP != nil && id == int(exporter.SysId) { // valid exporter
 			fmt.Printf("  SysID: %d, ID: %d, IP: %v, version: %d", exporter.SysId, exporter.Id, exporter.IP, exporter.Version)
 			fmt.Printf(" Sequence failures: %d, packets: %d, flows: %d\n", exporter.SequenceFailures, exporter.Packets, exporter.Flows)
+			for _, sampler := range exporter.SamplerList {
+				fmt.Printf("  Sampler: id: %d, algorithm: %d, packet interval: %d, space interval: %d\n",
+					sampler.Id, sampler.Algorithm, sampler.PacketInterval, sampler.SpaceInterval)
+			}
 		}
 	}
 }

exporter.go

@@ -15,6 +15,13 @@ import (
 	"unsafe"
 )
 
+type Sampler struct {
+	Id             int64
+	Algorithm      uint16
+	PacketInterval uint32
+	SpaceInterval  uint32
+}
+
 type Exporter struct {
 	IP               net.IP // IP address
 	isV4             bool
@@ -25,6 +32,7 @@ type Exporter struct {
 	Packets          uint64 // number of packets sent by this exporter
 	Flows            uint64 // number of flow records sent by this exporter
 	SequenceFailures uint32 // number of sequence failures
+	SamplerList      []Sampler
 }
 
 const MaxExporters = 256
@@ -84,6 +92,21 @@ func (nfFile *NfFile) addExporterStat(record []byte) {
 }
 
 func (nfFile *NfFile) addSampler(record []byte) {
+	samplerInfo := (*SamplerRecord)(unsafe.Pointer(&record[0]))
+
+	maxExporterID := len(nfFile.ExporterList)
+	if samplerInfo.Sysid >= uint16(maxExporterID) || nfFile.ExporterList[samplerInfo.Sysid].IP == nil {
+		// no valid exporter avilable
+		fmt.Printf("No valid exporter for new sampler\n")
+		return
+	}
+
+	nfFile.ExporterList[samplerInfo.Sysid].SamplerList = append(nfFile.ExporterList[samplerInfo.Sysid].SamplerList, Sampler{
+		Id:             samplerInfo.Id,
+		Algorithm:      samplerInfo.Algorithm,
+		PacketInterval: samplerInfo.PacketInterval,
+		SpaceInterval:  samplerInfo.SpaceInterval,
+	})
 
 }
 

exporter.h

@@ -79,4 +79,20 @@ typedef struct exporter_stats_record_s {
 
 } exporter_stats_record_t;
 
+typedef struct sampler_record_s {
+    // record header
+    uint16_t type;
+    uint16_t size;
+
+    // sampler data
+    uint16_t exporter_sysid;  // internal reference to exporter
+    uint16_t algorithm;       // #304 sampling algorithm
+    int64_t id;               // #302 id assigned by the exporting device or
+#define SAMPLER_OVERWRITE -3
+#define SAMPLER_DEFAULT -2
+#define SAMPLER_GENERIC -1
+    uint32_t packetInterval;  // #305 packet interval
+    uint32_t spaceInterval;   // #306 packet space
+} sampler_record_t;
+
 #endif

nfxV3.go

@@ -208,3 +208,28 @@ func (flowRecord *FlowRecordV3) IpReceived() *EXipReceived {
 	// no IP received
 	return nil
 }
+
+// get sampler info for flow record
+func (flowRecord *FlowRecordV3) SamplerInfo(nfFile *NfFile) (packetInterval int, spaceInterval int) {
+
+	// default values - no sampling
+	packetInterval = 1
+	spaceInterval = 0
+
+	maxExporterID := len(nfFile.ExporterList)
+	exporterID := flowRecord.recordHeader.ExporterID
+
+	if exporterID >= uint16(maxExporterID) || nfFile.ExporterList[exporterID].IP == nil {
+		return
+	}
+
+	exporter := nfFile.ExporterList[exporterID]
+
+	// samplers are added in sequence and may overwrite previous samplers
+	// the last in chain is currently valid
+	for _, sampler := range exporter.SamplerList {
+		packetInterval = int(sampler.PacketInterval)
+		spaceInterval = int(sampler.SpaceInterval)
+	}
+	return
+}