I am trying to get the OctetString value from an SNMP PDU returned by the gosnmp package. Even the bytes would suffice.
Here is my code:
package snmp_abstract
import (
"github.com/soniah/gosnmp"
"time"
"log"
"os"
"strings"
)
type Switch struct {
Hostname string
Connection gosnmp.GoSNMP
}
var ConnectionParams = &gosnmp.GoSNMP{
Target: "",
Port: 161,
Community: "community",
Version: gosnmp.Version2c,
Timeout: time.Duration(5) * time.Second,
Logger: log.New(os.Stdout, "", 0),
}
type Mibs struct {
VtpVlanState,
Dot1dBasePortIfIndex string
}
var Default = &Mibs{
VtpVlanState: "1.3.6.1.4.1.9.9.46.1.3.1.1.2",
Dot1dBasePortIfIndex: "1.3.6.1.2.1.17.1.4.1.2",
}
func SNMPGet(conn *gosnmp.GoSNMP, host string, mib []string) {
conn.Target = host
log.Println(conn)
err := conn.Connect()
if err != nil {
log.Printf("Unable to connect to %s\n", host)
}
defer conn.Conn.Close()
res, err := conn.Get(mib)
if err != nil {
log.Println("GET error")
log.Print(err)
}
log.Println(res)
}
func SNMPWalk(conn *gosnmp.GoSNMP, host string, mib string) []gosnmp.SnmpPDU {
conn.Target = host
log.Println(conn)
err := conn.Connect()
if err != nil {
log.Printf("Unable to connect to %s\n", host)
}
defer conn.Conn.Close()
res, err := conn.BulkWalkAll(mib)
if err != nil {
log.Println("GET error")
log.Print(err)
}
return res
}
func (sw *Switch) Vlans() []string {
res := SNMPWalk(&sw.Connection, sw.Hostname, Default.VtpVlanState)
var vlans = make([]string, len(res))
for i, vlan := range res {
oidSlice := strings.Split(vlan.Name, ".")
v := oidSlice[len(oidSlice)-1]
vlans[i] = v
}
return vlans
}
func (sw *Switch) MapBPIIfindex(vlan string) {
log.Println(vlan)
s := *sw
s.Connection.Community += "@" + vlan
log.Println(s.Connection.Community)
res := SNMPWalk(&s.Connection, s.Hostname, Default.Dot1dBasePortIfIndex)
for _, p := range res {
log.Println(p.Name)
log.Println(p.Value)
}
}
When I use the MapBPIIfindex method I get the following output:
OID: [.1.3.6.1.2.1.31.1.1.1.1.10001]
[decodeValue: type is OctetString]
decodeValue: value is []interface {}{[]uint8{0x46, 0x61, 0x30, 0x2f, 0x31}}
Now, this should contain an OctetString. The uint8 bytes should decode to Fa0/1, but I am not able to do this.
When I change log.Println(p.Value) to log.Println(p.Value.([]uint8)), I get the following error:
2017/05/29 12:54:59 .1.3.6.1.2.1.17.1.4.1.2
panic: interface conversion: interface {} is nil, not []uint8
How can I get this value? The documentation is not so clear on this.
