first

.drone.yml

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+workspace:
+  base: /go
+pipeline:
+  build:
+      image: golang:${GO_VERSION}    
+      commands:
+        - go get -v
+        - go test -v
+        - go build -v
+matrix:
+  GO_VERSION:    
+    - 1.7
+  GO_ARCH:
+    - amd64
+    - 386

.gitignore

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+*.exe
+gocdp

README.md

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+# GoCDP
+
+Show CDP over snmp
+
+Example run:
+
+```bash
+gocdp nei -s 10.0.0.1
+```
+Command line help
+```bash
+NAME:
+   gocdp - show CDP by snmp
+
+USAGE:
+   gocdp [global options] command [command options] [arguments...]
+
+VERSION:
+   1.0.3
+
+AUTHOR(S):
+   hdhog <[email protected]> 
+
+COMMANDS:
+     neigbors, n, nei  Show CDP neigbors by snmp
+     help, h           Shows a list of commands or help for one command
+
+GLOBAL OPTIONS:
+   --help, -h     show help
+   --version, -v  print the version
+
+```
+```bash
+NAME:
+   gocdp neigbors - Show CDP neigbors by snmp
+
+USAGE:
+   gocdp neigbors [command options] [arguments...]
+
+OPTIONS:
+   --community value, -c value  community string (default: "public")
+   --host value, -s value       host address
+
+```

main.go

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+package main
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"sort"
+	"strings"
+
+	"github.com/k-sone/snmpgo"
+	"github.com/olekukonko/tablewriter"
+	"github.com/urfave/cli"
+)
+
+const (
+	oidSysName            = "1.3.6.1.2.1.1.5"
+	oidIfDescr            = "1.3.6.1.2.1.2.2.1.2"
+	oidCDPCacheEntry      = "1.3.6.1.4.1.9.9.23.1.2.1.1"
+	oidCDPCacheDeviceid   = "1.3.6.1.4.1.9.9.23.1.2.1.1.6"
+	oidCDPCacheDevicePort = "1.3.6.1.4.1.9.9.23.1.2.1.1.7"
+	oidCDPCacheAddress    = "1.3.6.1.4.1.9.9.23.1.2.1.1.4"
+	cacheAddress          = 4
+	cacheDeviceid         = 6
+	cacheDevicePort       = 7
+)
+
+// Информация о версии приложения
+var (
+	Version = "0.0.1"
+)
+
+type cdpNeighbor struct {
+	LName   string
+	LIP     string
+	LIfName string
+	RName   string
+	RIP     string
+	RIfName string
+}
+
+func compactIfName(ifname string) string {
+	if strings.HasPrefix(ifname, "Ten") {
+		return strings.Replace(ifname, "TenGigabitEthernet", "Te ", -1)
+	}
+	if strings.HasPrefix(ifname, "Gig") {
+		return strings.Replace(ifname, "GigabitEthernet", "Gi ", -1)
+	}
+	if strings.HasPrefix(ifname, "Fas") {
+		return strings.Replace(ifname, "FastEthernet", "Fa ", -1)
+	}
+	return ifname
+}
+
+func prepareOids() (snmpgo.Oids, error) {
+	return snmpgo.NewOids([]string{
+		oidCDPCacheDeviceid,
+		oidCDPCacheDevicePort,
+		oidCDPCacheAddress,
+		oidIfDescr,
+		oidSysName,
+	})
+}
+
+func getCDPNeighbors(host, community string) (map[string]cdpNeighbor, error) {
+	nei := map[string]cdpNeighbor{}
+
+	snmpAddr := net.JoinHostPort(host, "161")
+
+	snmp, err := snmpgo.NewSNMP(snmpgo.SNMPArguments{
+		Version:   snmpgo.V2c,
+		Address:   snmpAddr,
+		Retries:   1,
+		Community: community,
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	cacheEntry, err := prepareOids()
+
+	if err != nil {
+		return nil, err
+	}
+
+	if err = snmp.Open(); err != nil {
+		return nil, err
+	}
+	defer snmp.Close()
+
+	pdu, err := snmp.GetBulkWalk(cacheEntry, 0, 10)
+	if err != nil {
+		return nil, err
+	}
+
+	if pdu.ErrorStatus() != snmpgo.NoError {
+		fmt.Println(pdu.ErrorStatus(), pdu.ErrorIndex())
+	}
+
+	oid, err := snmpgo.NewOid(oidCDPCacheEntry)
+	if err != nil {
+		return nil, err
+	}
+	cacheEntrys := pdu.VarBinds().MatchBaseOids(oid)
+	sysName := pdu.VarBinds().MatchBaseOids(snmpgo.MustNewOid(oidSysName))[0]
+
+	for _, val := range cacheEntrys {
+		ifindex := fmt.Sprintf("%d", val.Oid.Value[14])
+		if _, ok := nei[ifindex]; !ok {
+			oid, err = snmpgo.NewOid(oidIfDescr + "." + ifindex)
+			if err != nil {
+				return nil, err
+			}
+			ifnames := pdu.VarBinds().MatchBaseOids(oid)
+			rifname := ifnames.MatchOid(oid).Variable.String()
+			nei[ifindex] = cdpNeighbor{
+				RIfName: compactIfName(rifname),
+			}
+		}
+
+		cdp := nei[ifindex]
+		cdp.RName = sysName.Variable.String()
+		cdp.RIP = host
+
+		switch val.Oid.Value[13] {
+		case cacheAddress:
+			cdp.LIP = val.Variable.String()
+			var ip, ip1, ip2, ip3 int
+			fmt.Sscanf(val.Variable.String(), "%x:%x:%x:%x", &ip, &ip1, &ip2, &ip3)
+			cdp.LIP = fmt.Sprintf("%d.%d.%d.%d", ip, ip1, ip2, ip3)
+		case cacheDeviceid:
+			cdp.LName = val.Variable.String()
+		case cacheDevicePort:
+			cdp.LIfName = compactIfName(val.Variable.String())
+		}
+
+		nei[ifindex] = cdp
+	}
+
+	return nei, nil
+}
+
+func printTable(neigbors map[string]cdpNeighbor) {
+	table := tablewriter.NewWriter(os.Stdout)
+	table.SetHeader([]string{"Name", "IP", "Local IF", "--", "Remote IF", "Remote IP", "Remote Name"})
+	table.SetBorder(false)
+	var data [][]string
+	var keys []string
+	for k := range neigbors {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	for _, k := range keys {
+		v := neigbors[k]
+		data = append(data, []string{v.RName, v.RIP, v.RIfName, "->", v.LIfName, v.LIP, v.LName})
+	}
+	table.SetAlignment(4)
+	table.AppendBulk(data)
+	table.Render()
+}
+
+func neighbors(c *cli.Context) error {
+	community := c.String("community")
+	host := c.String("host")
+	if host == "" {
+		if err := cli.ShowCommandHelp(c, "neigbors"); err != nil {
+			return err
+		}
+		return cli.NewExitError("Host address required", 1)
+	}
+	res, err := getCDPNeighbors(host, community)
+	if err != nil {
+		return cli.NewExitError(err.Error(), 1)
+	}
+	printTable(res)
+
+	return nil
+}
+
+func main() {
+	app := cli.NewApp()
+	app.Name = "gocdp"
+	app.Usage = "show CDP by snmp"
+	app.Version = Version
+	app.Authors = []cli.Author{
+		cli.Author{
+			Name:  "hdhog",
+			Email: "[email protected]",
+		},
+	}
+	app.Commands = []cli.Command{
+		{
+			Name:    "neigbors",
+			Aliases: []string{"n", "nei"},
+			Usage:   "Show CDP neigbors over snmp",
+			Flags: []cli.Flag{
+				cli.StringFlag{
+					Name:  "community, c",
+					Value: "public",
+					Usage: "community string",
+				},
+				cli.StringFlag{
+					Name:  "host ,s",
+					Usage: "host address",
+				},
+			},
+			Action: neighbors,
+		},
+	}
+
+	if err := app.Run(os.Args); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}

main_test.go

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+package main
+
+import "testing"
+
+func Test_compactIfName(t *testing.T) {
+	t.Run("Ifname", func(t *testing.T) {
+		t.Run("FastEthernet", func(t *testing.T) {
+			data := compactIfName("FastEthernet0/1")
+			if data != "Fa 0/1" {
+				t.Error("Error compaction ifname")
+			}
+		})
+		t.Run("GigabitEthernet", func(t *testing.T) {
+			data := compactIfName("GigabitEthernet0/1")
+			if data != "Gi 0/1" {
+				t.Error("Error compaction ifname")
+			}
+		})
+		t.Run("TenGigabitEthernet", func(t *testing.T) {
+			data := compactIfName("TenGigabitEthernet0/1")
+			if data != "Te 0/1" {
+				t.Error("Error compaction ifname")
+			}
+		})
+	})
+}