gosnmp

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// Copyright 2020 The GoSNMP Authors. All rights reserved.  Use of this
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// source code is governed by a BSD-style license that can be found in the
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// LICENSE file.
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package main
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import (
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	"fmt"
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	"log"
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	"net"
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	"time"
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	gosnmp "github.com/gosnmp/gosnmp"
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)
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func main() {
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	log.Println("Starting")
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	var port uint16 = 2162
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	go Start(fmt.Sprintf("tcp://0.0.0.0:%d", port))
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	gosnmp.Default.Target = "127.0.0.1"
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	gosnmp.Default.Transport = "tcp"
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	gosnmp.Default.Port = port
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	gosnmp.Default.Community = "public"
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	gosnmp.Default.Version = gosnmp.Version1
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	time.Sleep(time.Duration(1) * time.Second)
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	oid := gosnmp.SnmpPDU{
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		Name:  "1.3.6.1.2.1.1.6",
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		Type:  gosnmp.ObjectIdentifier,
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		Value: "1.3.6.1.2.1.1.6.10",
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	}
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	oid1 := gosnmp.SnmpPDU{
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		Name:  "1.3.6.1.2.1.1.7",
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		Type:  gosnmp.OctetString,
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		Value: "Testing TCP trap...",
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	}
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	oid2 := gosnmp.SnmpPDU{
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		Name:  "1.3.6.1.2.1.1.8",
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		Type:  gosnmp.Integer,
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		Value: 123,
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	}
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	cou := 5
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	for cou > 0 {
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		time.Sleep(time.Duration(1) * time.Second)
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		err := gosnmp.Default.Connect()
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		if err != nil {
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			log.Fatal(err)
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		}
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		defer gosnmp.Default.Conn.Close()
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		//RebuildCron()
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		log.Printf("Running (%d)\n", cou)
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		trap := gosnmp.SnmpTrap{
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			Variables:    []gosnmp.SnmpPDU{oid, oid1, oid2},
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			Enterprise:   ".1.3.6.1.6.3.1.1.5.1",
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			AgentAddress: "127.0.0.1",
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			GenericTrap:  0,
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			SpecificTrap: 0,
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			Timestamp:    300,
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		}
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		_, err = gosnmp.Default.SendTrap(trap)
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		if err != nil {
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			log.Fatalf("SendTrap() err: %v\n", err)
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		}
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		cou--
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	}
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	//time.Sleep(time.Duration(10) * time.Second)
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	log.Println("Stop...")
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}
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// Start SNMP server
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func Start(address string) {
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	log.Printf("Starting SNMP TRAP Server on: %s\n", address)
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	tl := gosnmp.NewTrapListener()
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	tl.OnNewTrap = myTrapHandlerTCP
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	tl.Params = gosnmp.Default
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	err := tl.Listen(address)
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	if err != nil {
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		time.Sleep(1 * time.Second)
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		log.Fatalf("Error in TRAP listen: %s\n", err)
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	}
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}
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func myTrapHandlerTCP(packet *gosnmp.SnmpPacket, addr *net.UDPAddr) {
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	log.Printf("SNMP trap received from: %s:%d. Community:%s, SnmpVersion:%s\n",
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		addr.IP, addr.Port, packet.Community, packet.Version)
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	for i, variable := range packet.Variables {
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		var val string
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		switch variable.Type {
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		case gosnmp.OctetString:
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			val = string(variable.Value.([]byte))
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		case gosnmp.ObjectIdentifier:
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			val = fmt.Sprintf("%s", variable.Value)
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		case gosnmp.TimeTicks:
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			a := gosnmp.ToBigInt(variable.Value)
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			val = fmt.Sprintf("%d", (*a).Int64())
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		case gosnmp.Null:
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			val = ""
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		default:
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			// ... or often you're just interested in numeric values.
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			// ToBigInt() will return the Value as a BigInt, for plugging
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			// into your calculations.
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			a := gosnmp.ToBigInt(variable.Value)
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			val = fmt.Sprintf("%d", (*a).Int64())
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		}
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		log.Printf("- oid[%d]: %s (%s) = %v \n", i, variable.Name, variable.Type, val)
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	}
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}
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