forked from Juniper/go-netconf
/
transport.go
171 lines (144 loc) · 3.78 KB
/
transport.go
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// Go NETCONF Client
//
// Copyright (c) 2013-2018, Juniper Networks, Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package netconf
import (
"bytes"
"encoding/xml"
"fmt"
"io"
"regexp"
)
const (
// msgSeperator is used to separate sent messages via NETCONF
msgSeperator = "]]>]]>"
)
// DefaultCapabilities sets the default capabilities of the client library
var DefaultCapabilities = []string{
"urn:ietf:params:netconf:base:1.0",
}
// HelloMessage is used when bringing up a NETCONF session
type HelloMessage struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:netconf:base:1.0 hello"`
Capabilities []string `xml:"capabilities>capability"`
SessionID int `xml:"session-id,omitempty"`
}
// Transport interface defines what characterisitics make up a NETCONF transport
// layer object.
type Transport interface {
Send([]byte) error
Receive() ([]byte, error)
Close() error
ReceiveHello() (*HelloMessage, error)
SendHello(*HelloMessage) error
}
type transportBasicIO struct {
io.ReadWriteCloser
}
// Sends a well formated NETCONF rpc message as a slice of bytes adding on the
// nessisary framining messages.
func (t *transportBasicIO) Send(data []byte) error {
t.Write(data)
// Pad to make sure the msgSeparator isn't sent across a 4096-byte boundary
if (len(data)+len(msgSeperator))%4096 < 6 {
t.Write([]byte(" "))
}
t.Write([]byte(msgSeperator))
t.Write([]byte("\n"))
return nil // TODO: Implement error handling!
}
func (t *transportBasicIO) Receive() ([]byte, error) {
return t.WaitForBytes([]byte(msgSeperator))
}
func (t *transportBasicIO) SendHello(hello *HelloMessage) error {
val, err := xml.Marshal(hello)
if err != nil {
return err
}
header := []byte(xml.Header)
val = append(header, val...)
err = t.Send(val)
return err
}
func (t *transportBasicIO) ReceiveHello() (*HelloMessage, error) {
hello := new(HelloMessage)
val, err := t.Receive()
if err != nil {
return hello, err
}
err = xml.Unmarshal(val, hello)
return hello, err
}
func (t *transportBasicIO) Writeln(b []byte) (int, error) {
t.Write(b)
t.Write([]byte("\n"))
return 0, nil
}
func (t *transportBasicIO) WaitForFunc(f func([]byte) (int, error)) ([]byte, error) {
var out bytes.Buffer
buf := make([]byte, 4096)
pos := 0
for {
n, err := t.Read(buf[pos : pos+(len(buf)/2)])
if err != nil {
if err != io.EOF {
return nil, err
}
break
}
if n > 0 {
end, err := f(buf[0 : pos+n])
if err != nil {
return nil, err
}
if end > -1 {
out.Write(buf[0:end])
return out.Bytes(), nil
}
if pos > 0 {
out.Write(buf[0:pos])
copy(buf, buf[pos:pos+n])
}
pos = n
}
}
return nil, fmt.Errorf("WaitForFunc failed")
}
func (t *transportBasicIO) WaitForBytes(b []byte) ([]byte, error) {
return t.WaitForFunc(func(buf []byte) (int, error) {
return bytes.Index(buf, b), nil
})
}
func (t *transportBasicIO) WaitForString(s string) (string, error) {
out, err := t.WaitForBytes([]byte(s))
if out != nil {
return string(out), err
}
return "", err
}
func (t *transportBasicIO) WaitForRegexp(re *regexp.Regexp) ([]byte, [][]byte, error) {
var matches [][]byte
out, err := t.WaitForFunc(func(buf []byte) (int, error) {
loc := re.FindSubmatchIndex(buf)
if loc != nil {
for i := 2; i < len(loc); i += 2 {
matches = append(matches, buf[loc[i]:loc[i+1]])
}
return loc[1], nil
}
return -1, nil
})
return out, matches, err
}
// ReadWriteCloser represents a combined IO Reader and WriteCloser
type ReadWriteCloser struct {
io.Reader
io.WriteCloser
}
// NewReadWriteCloser creates a new combined IO Reader and Write Closer from the
// provided objects
func NewReadWriteCloser(r io.Reader, w io.WriteCloser) *ReadWriteCloser {
return &ReadWriteCloser{r, w}
}