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ergo/vendor/github.com/oragono/go-ident/client.go

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// Package ident implements an RFC 1413 client
package ident
import (
"bufio"
"fmt"
"net"
"strings"
"time"
)
// Response is a successful answer to our query to the identd server.
type Response struct {
OS string
Charset string
Identifier string
}
// ResponseError indicates that the identd server returned an error rather than an
// identifying string.
type ResponseError struct {
Type string
}
func (e ResponseError) Error() string {
return fmt.Sprintf("Ident error: %s", e.Type)
}
// ProtocolError indicates that an error occurred with the protocol itself, that the response
// could not be successfully parsed or was malformed.
type ProtocolError struct {
Line string
}
func (e ProtocolError) Error() string {
return fmt.Sprintf("Unexpected response from server: %s", e.Line)
}
// Query makes an Ident query, if timeout is >0 the query is timed out after that many seconds.
func Query(ip string, portOnServer, portOnClient int, timeout float64) (Response, error) {
var (
conn net.Conn
err error
fields []string
r *bufio.Reader
resp string
)
if timeout > 0 {
conn, err = net.DialTimeout("tcp", net.JoinHostPort(ip, "113"), time.Duration(timeout)*time.Second)
} else {
conn, err = net.Dial("tcp", net.JoinHostPort(ip, "113"))
}
if err != nil {
return Response{}, err
}
// stop the ident read after <timeout> seconds
if timeout > 0 {
conn.SetDeadline(time.Now().Add(time.Second * time.Duration(timeout)))
}
_, err = conn.Write([]byte(fmt.Sprintf("%d, %d", portOnClient, portOnServer) + "\r\n"))
if err != nil {
return Response{}, err
}
r = bufio.NewReader(conn)
resp, err = r.ReadString('\n')
if err != nil {
return Response{}, err
}
fields = strings.SplitN(strings.TrimSpace(resp), " : ", 4)
if len(fields) < 3 {
return Response{}, ProtocolError{resp}
}
switch fields[1] {
case "USERID":
if len(fields) != 4 {
return Response{}, ProtocolError{resp}
}
var os, charset string
osAndCharset := strings.SplitN(fields[2], ",", 2)
if len(osAndCharset) == 2 {
os = osAndCharset[0]
charset = osAndCharset[1]
} else {
os = osAndCharset[0]
charset = "US-ASCII"
}
return Response{
OS: os,
Charset: charset,
Identifier: fields[3],
}, nil
case "ERROR":
if len(fields) != 3 {
return Response{}, ProtocolError{resp}
}
return Response{}, ResponseError{fields[2]}
}
return Response{}, err
}