Use headers to check ip addresses for use behind proxy

• Break file up to multiple files
 • Can pass in headers through command line arguments, defaults for
   checking X-Real-IP and X-Forwarded-For
 • Add logging for requests with timing
 • Add 404 support for missing URLs
master
Buddy Sandidge 8 years ago
parent 77fe2532d5
commit ba99b61aa0

33
ip.go

@ -0,0 +1,33 @@
package main
import (
"errors"
"net"
)
// IP is the net.IP with a version string to allow storing the version
type IP struct {
net.IP
version string
}
func (ip *IP) isV6() bool {
return ip.To4() == nil
}
// NewIP returns a new instance of an IP address
func NewIP(addr string) (*IP, error) {
parsedIP := net.ParseIP(addr)
if parsedIP == nil {
return nil, errors.New("Could not parse address " + addr)
}
result := &IP{parsedIP, ""}
if result.isV6() {
result.version = "v6"
} else {
result.version = "v4"
}
return result, nil
}

@ -0,0 +1,35 @@
package main
import (
"log"
"net/http"
"os"
"time"
)
// Logger interface
type Logger interface {
Println(v ...interface{})
Printf(format string, v ...interface{})
}
// LoggerHandler interface
type LoggerHandler interface {
Logger
ServeHTTP(http.ResponseWriter, *http.Request, http.HandlerFunc)
}
// NewLogger returns a logger interface
func NewLogger() LoggerHandler {
return &logger{log.New(os.Stdout, appLabel, log.Ldate|log.Lmicroseconds)}
}
type logger struct {
Logger
}
func (l *logger) ServeHTTP(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
start := time.Now()
next(rw, r)
l.Printf("Completed %s to %s in %v", r.Method, r.URL.Path, time.Since(start))
}

@ -0,0 +1,55 @@
package main
import (
"io"
"net"
"net/http"
)
// Server that handles http responses
type Server struct {
headerNames []string
logger LoggerHandler
}
func (s *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
for _, headerName := range s.headerNames {
possibleIP := req.Header.Get(headerName)
if possibleIP == "" {
continue
}
ip, err := NewIP(possibleIP)
if err != nil {
continue
}
s.sendResponse(w, ip)
return
}
addr, _, err := net.SplitHostPort(req.RemoteAddr)
if err != nil {
s.handleError(w, http.StatusBadRequest, err, "Could not get IP address from request")
return
}
ip, err := NewIP(addr)
if err != nil {
s.handleError(w, http.StatusBadRequest, err, "Could not parse IP address"+addr)
return
}
s.sendResponse(w, ip)
}
func (s *Server) sendResponse(resp http.ResponseWriter, ip *IP) {
io.WriteString(resp, ip.String()+"\n")
s.logger.Printf("Request from %s %s\n", ip.version, ip)
}
func (s *Server) handleError(resp http.ResponseWriter, status int, err error, message string) {
resp.WriteHeader(status)
io.WriteString(resp, message)
s.logger.Printf("Error handling request: %s (%s)", message, err)
}

@ -1,20 +1,24 @@
package main
import (
"fmt"
"io"
"log"
"net"
"errors"
"net/http"
"os"
"github.com/gorilla/pat"
"github.com/urfave/cli"
"github.com/urfave/negroni"
)
const (
appName = "what-is-my-ip"
appLabel = "[" + appName + "] "
)
func main() {
app := cli.NewApp()
app.Name = "what-is-my-ip"
app.Version = "0.2.0"
app.Name = appName
app.Version = "0.3.0"
app.Usage = "Webapp that gives the IP address for incoming requests"
app.Action = action
@ -26,6 +30,12 @@ func main() {
Usage: "Address and port to bind to",
},
cli.StringSliceFlag{
Name: "header, H",
Value: &cli.StringSlice{"X-Real-IP", "X-Forwarded-For"},
Usage: "Headers to check in before checking the request itself",
},
cli.StringFlag{
Name: "certificate, c",
Value: "cert.pem",
@ -45,26 +55,38 @@ func main() {
}
func action(c *cli.Context) error {
http.HandleFunc("/", getIP)
address := c.String("address")
certificate := c.String("certificate")
key := c.String("key")
fmt.Printf("listening on %s\n", address)
return http.ListenAndServeTLS(address, certificate, key, nil)
handler, service := getHandler(c.StringSlice("header"))
service.logger.Printf("listening on %s\n", address)
return http.ListenAndServeTLS(address, certificate, key, handler)
}
func getIP(w http.ResponseWriter, req *http.Request) {
ip, _, err := net.SplitHostPort(req.RemoteAddr)
if err != nil {
handleError(w, err, "Could not get IP address from request")
return
func getHandler(headers []string) (http.Handler, *Server) {
service := &Server{
headerNames: headers,
logger: NewLogger(),
}
io.WriteString(w, ip+"\n")
log.Printf("Give response IP %s\n", ip)
}
func handleError(resp http.ResponseWriter, err error, message string) {
resp.WriteHeader(http.StatusBadRequest)
io.WriteString(resp, message)
log.Printf("Error handling request: %s (%s)", message, err)
recover := negroni.NewRecovery()
recover.Logger = service.logger
router := pat.New()
router.Get("/", func(resp http.ResponseWriter, req *http.Request) {
if req.URL.Path == "/" {
service.ServeHTTP(resp, req)
} else {
err := errors.New("path \"" + req.URL.Path + "\" not found")
service.handleError(resp, http.StatusNotFound, err, "404 page not found\n")
}
})
n := negroni.New()
n.Use(recover)
n.Use(service.logger)
n.UseHandler(router)
return n, service
}

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