// unmarshal stores in v the value part of binding b.
func (b *binding) unmarshal(v interface{}) error {
convertClass(&b.Value)
_, err := asn1.Unmarshal(b.Value.FullBytes, v)
if err != nil {
if _, ok := err.(asn1.StructuralError); ok {
return fmt.Errorf("type mismatch: {class:%d tag:%d} vs. %T: %v",
b.Value.Class, b.Value.Tag, v, err)
}
return err
}
v = convertType(v)
return nil
}
func (s *SNMP) do(req *request) (*response, error) {
for i := range req.Bindings {
req.Bindings[i].Value = null
}
var buf []byte
var err error
switch req.Type {
case "Get":
var p struct {
Version int
Community []byte
Data struct {
RequestID int32
ErrorStatus int
ErrorIndex int
Bindings []binding
} `asn1:"application,tag:0"`
}
p.Version = 1
p.Community = []byte(s.Community)
p.Data.RequestID = req.ID
p.Data.Bindings = req.Bindings
buf, err = asn1.Marshal(p)
case "GetNext":
var p struct {
Version int
Community []byte
Data struct {
RequestID int32
ErrorStatus int
ErrorIndex int
Bindings []binding
} `asn1:"application,tag:1"`
}
p.Version = 1
p.Community = []byte(s.Community)
p.Data.RequestID = req.ID
p.Data.Bindings = req.Bindings
buf, err = asn1.Marshal(p)
case "GetBulk":
var p struct {
Version int
Community []byte
Data struct {
RequestID int32
NonRepeaters int
MaxRepetitions int
Bindings []binding
} `asn1:"application,tag:5"`
}
p.Version = 1
p.Community = []byte(s.Community)
p.Data.RequestID = req.ID
p.Data.NonRepeaters = 0
p.Data.MaxRepetitions = req.MaxRepetitions
p.Data.Bindings = req.Bindings
buf, err = asn1.Marshal(p)
default:
panic("unsupported type " + req.Type)
}
if err != nil {
return nil, err
}
conn, err := net.DialUDP("udp", nil, s.Addr)
if err != nil {
return nil, err
}
defer conn.Close()
if _, err := conn.Write(buf); err != nil {
return nil, err
}
buf = make([]byte, 10000, 10000)
if err := conn.SetReadDeadline(time.Now().Add(5 * time.Second)); err != nil {
return nil, err
}
n, err := conn.Read(buf)
if err != nil {
return nil, err
}
if n == len(buf) {
return nil, fmt.Errorf("response too big")
}
var p struct {
Version int
Community []byte
Data struct {
RequestID int32
ErrorStatus int
ErrorIndex int
Bindings []binding
} `asn1:"tag:2"`
}
if _, err = asn1.Unmarshal(buf[:n], &p); err != nil {
return nil, err
}
resp := &response{p.Data.RequestID, p.Data.ErrorStatus, p.Data.ErrorIndex, p.Data.Bindings}
return resp, nil
}