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/*
* Copyright (c) 2023 DomainTools LLC
* Copyright (c) 2017 by Farsight Security, Inc.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
package nmsg
import (
"fmt"
"reflect"
"strings"
)
var types map[uint32]map[uint32]reflect.Type
var typesByName map[uint32]map[string]uint32
var vendors map[uint32]string
var vids map[string]uint32
// Register records the supplied message's type, indexed by its MessageType
// and VendorID, for the purposes of decoding protobuf-encoded payloads.
//
// Register should be called from the init() function of the module defining
// the payload type. It is not safe to call from multiple goroutines, and
// may not be called if any goroutine is concurrently decoding NMSG payloads.
func Register(m Message) {
if types == nil {
types = make(map[uint32]map[uint32]reflect.Type)
typesByName = make(map[uint32]map[string]uint32)
}
vid := m.GetVid()
v, ok := types[vid]
if !ok {
v = make(map[uint32]reflect.Type)
types[vid] = v
}
msgtype := m.GetMsgtype()
v[msgtype] = reflect.TypeOf(m)
name := strings.ToLower(v[msgtype].Elem().Name())
tn, ok := typesByName[vid]
if !ok {
tn = make(map[string]uint32)
typesByName[vid] = tn
}
tn[name] = msgtype
}
// RegisterVendor records an association between the vendor named `vname`
// and a numeric vendor id `vid`
func RegisterVendor(vname string, vid uint32) {
if vendors == nil {
vendors = make(map[uint32]string)
vids = make(map[string]uint32)
}
vendors[vid] = vname
vids[vname] = vid
}
type unknownVid uint32
func (v unknownVid) Error() string {
return fmt.Sprintf("Vendor %d not registered.", v)
}
type unknownVendor string
func (v unknownVendor) Error() string {
return fmt.Sprintf("Vendor '%s' not registered.", string(v))
}
type unknownMsgtype struct{ vid, msgtype uint32 }
func (t unknownMsgtype) Error() string {
return fmt.Sprintf("Msgtype %d is not registered for vendor %d.", t.msgtype, t.vid)
}
// NewMessage creates a new Message with an underlying type identified
// by vid, msgtype.
func NewMessage(vid, msgtype uint32) (Message, error) {
v, ok := types[vid]
if !ok {
return nil, unknownVid(vid)
}
t, ok := v[msgtype]
if !ok {
return nil, unknownMsgtype{vid, msgtype}
}
return reflect.New(t.Elem()).Interface().(Message), nil
}
// VendorByname returns the numeric vendor id registered for the given
// name, if any.
func VendorByName(vname string) (uint32, error) {
vid, ok := vids[vname]
if !ok {
return 0, unknownVendor(vname)
}
return vid, nil
}
// VendorName returns the vendor name registered for the given
// numeric vid, if any.
func VendorName(vid uint32) (string, error) {
vname, ok := vendors[vid]
if !ok {
return "", unknownVid(vid)
}
return vname, nil
}
// MessageTypeByName returns the numeric vendor id and message type
// for the given vendor name and message type name, for the purposes
// of creating a new message with NewMessage().
func MessageTypeByName(vname string, mname string) (vid uint32, mtype uint32, err error) {
var ok bool
vid, err = VendorByName(vname)
if err != nil {
return
}
mtype, ok = typesByName[vid][strings.ToLower(mname)]
if !ok {
err = fmt.Errorf("Unknown message type '%s' for vendor '%s'", mname, vname)
}
return
}
// MessageTypeName returns a vendor and message type name for a given
// numeric vendor id and message type, if any
func MessageTypeName(vid uint32, msgtype uint32) (vname string, mname string, err error) {
var ok bool
vname, err = VendorName(vid)
if err != nil {
return
}
v, ok := types[vid]
if !ok {
err = unknownVid(vid)
return
}
t, ok := v[msgtype]
if !ok {
err = unknownMsgtype{vid, msgtype}
return
}
mname = strings.ToLower(t.Elem().Name())
return
}
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