echoip/ifconfig.go

203 lines
4.2 KiB
Go

package main
import (
"encoding/json"
"fmt"
"github.com/jessevdk/go-flags"
"github.com/oschwald/geoip2-golang"
"html/template"
"io"
"log"
"net"
"net/http"
"net/url"
"os"
"regexp"
"strings"
)
var agentExp = regexp.MustCompile("^(?i)(curl|wget|fetch\\slibfetch)\\/.*$")
type Client struct {
IP net.IP
JSON string
Header http.Header
Cmd
}
type Cmd struct {
Name string
Args string
}
type Ifconfig struct {
DB *geoip2.Reader
}
func (c *Cmd) String() string {
return c.Name + " " + c.Args
}
func isCLI(userAgent string) bool {
return agentExp.MatchString(userAgent)
}
func parseRealIP(req *http.Request) net.IP {
var host string
realIP := req.Header.Get("X-Real-IP")
if realIP != "" {
host = realIP
} else {
host, _, _ = net.SplitHostPort(req.RemoteAddr)
}
return net.ParseIP(host)
}
func pathToKey(path string) string {
trimmed := strings.TrimSuffix(strings.TrimPrefix(path, "/"), ".json")
return strings.ToLower(trimmed)
}
func isJSON(req *http.Request) bool {
return strings.HasSuffix(req.URL.Path, ".json") ||
strings.Contains(req.Header.Get("Accept"), "application/json")
}
func (i *Ifconfig) LookupCountry(ip net.IP) (string, error) {
if i.DB == nil {
return "", nil
}
record, err := i.DB.Country(ip)
if err != nil {
return "", err
}
country, exists := record.Country.Names["en"]
if !exists {
country, exists = record.RegisteredCountry.Names["en"]
if !exists {
return "", fmt.Errorf(
"could not determine country for IP: %s", ip)
}
}
return country, nil
}
func (i *Ifconfig) JSON(req *http.Request, key string) (string, error) {
var header http.Header
if key == "all" {
header = req.Header
} else {
header = http.Header{
key: []string{req.Header.Get(key)},
}
}
b, err := json.MarshalIndent(header, "", " ")
if err != nil {
return "", err
}
return string(b), nil
}
func (i *Ifconfig) Plain(req *http.Request, key string, ip net.IP) string {
if key == "" || key == "ip" {
return fmt.Sprintf("%s\n", ip)
}
return fmt.Sprintf("%s\n", req.Header.Get(key))
}
func lookupCmd(values url.Values) Cmd {
cmd, exists := values["cmd"]
if !exists || len(cmd) == 0 {
return Cmd{Name: "curl"}
}
switch cmd[0] {
case "curl":
return Cmd{Name: "curl"}
case "fetch":
return Cmd{Name: "fetch", Args: "-qo -"}
case "wget":
return Cmd{Name: "wget", Args: "-qO -"}
}
return Cmd{Name: "curl"}
}
func (i *Ifconfig) handler(w http.ResponseWriter, req *http.Request) {
if req.Method != "GET" {
http.Error(w, "Invalid request method", 405)
return
}
ip := parseRealIP(req)
key := pathToKey(req.URL.Path)
cmd := lookupCmd(req.URL.Query())
country, err := i.LookupCountry(ip)
if err != nil {
log.Print(err)
}
req.Header["X-Ip-Country"] = []string{country}
if isJSON(req) {
out, err := i.JSON(req, key)
if err != nil {
log.Print(err)
http.Error(w, "Failed to marshal JSON", 500)
return
}
io.WriteString(w, out)
} else if isCLI(req.UserAgent()) {
io.WriteString(w, i.Plain(req, key, ip))
} else {
funcMap := template.FuncMap{
"ToLower": strings.ToLower,
}
t, _ := template.
New("index.html").
Funcs(funcMap).
ParseFiles("index.html")
b, err := json.MarshalIndent(req.Header, "", " ")
if err != nil {
log.Print(err)
http.Error(w, "Failed to marshal JSON", 500)
return
}
client := &Client{
IP: ip,
JSON: string(b),
Header: req.Header,
Cmd: cmd,
}
t.Execute(w, client)
}
}
func Create(path string) (*Ifconfig, error) {
if path == "" {
log.Print("Path to GeoIP database not given. Country lookup will be disabled")
return &Ifconfig{}, nil
}
db, err := geoip2.Open(path)
if err != nil {
return nil, err
}
return &Ifconfig{DB: db}, nil
}
func main() {
var opts struct {
DBPath string `short:"f" long:"file" description:"Path to GeoIP database" value-name:"FILE" default:""`
Listen string `short:"l" long:"listen" description:"Listening address" value-name:"ADDR" default:":8080"`
}
_, err := flags.ParseArgs(&opts, os.Args)
if err != nil {
os.Exit(1)
}
i, err := Create(opts.DBPath)
if err != nil {
log.Fatal(err)
}
http.HandleFunc("/", i.handler)
log.Printf("Listening on %s", opts.Listen)
if err := http.ListenAndServe(opts.Listen, nil); err != nil {
log.Fatal("ListenAndServe: ", err)
}
}