AdGuardHome/home/whois.go

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package home
import (
"encoding/binary"
"fmt"
"io/ioutil"
"net"
"strings"
"time"
"github.com/AdguardTeam/golibs/cache"
"github.com/AdguardTeam/golibs/log"
)
const (
defaultServer = "whois.arin.net"
defaultPort = "43"
maxValueLength = 250
whoisTTL = 1 * 60 * 60 // 1 hour
)
// Whois - module context
type Whois struct {
clients *clientsContainer
ipChan chan string
timeoutMsec uint
// Contains IP addresses of clients
// An active IP address is resolved once again after it expires.
// If IP address couldn't be resolved, it stays here for some time to prevent further attempts to resolve the same IP.
ipAddrs cache.Cache
}
// Create module context
func initWhois(clients *clientsContainer) *Whois {
w := Whois{}
w.timeoutMsec = 5000
w.clients = clients
cconf := cache.Config{}
cconf.EnableLRU = true
cconf.MaxCount = 10000
w.ipAddrs = cache.New(cconf)
w.ipChan = make(chan string, 255)
go w.workerLoop()
return &w
}
// If the value is too large - cut it and append "..."
func trimValue(s string) string {
if len(s) <= maxValueLength {
return s
}
return s[:maxValueLength-3] + "..."
}
// Parse plain-text data from the response
func whoisParse(data string) map[string]string {
m := map[string]string{}
descr := ""
netname := ""
for len(data) != 0 {
ln := SplitNext(&data, '\n')
if len(ln) == 0 || ln[0] == '#' || ln[0] == '%' {
continue
}
kv := strings.SplitN(ln, ":", 2)
if len(kv) != 2 {
continue
}
k := strings.TrimSpace(kv[0])
k = strings.ToLower(k)
v := strings.TrimSpace(kv[1])
switch k {
case "org-name":
m["orgname"] = trimValue(v)
case "orgname":
fallthrough
case "city":
fallthrough
case "country":
m[k] = trimValue(v)
case "descr":
if len(descr) == 0 {
descr = v
}
case "netname":
netname = v
case "whois": // "whois: whois.arin.net"
m["whois"] = v
case "referralserver": // "ReferralServer: whois://whois.ripe.net"
if strings.HasPrefix(v, "whois://") {
m["whois"] = v[len("whois://"):]
}
}
}
// descr or netname -> orgname
_, ok := m["orgname"]
if !ok && len(descr) != 0 {
m["orgname"] = trimValue(descr)
} else if !ok && len(netname) != 0 {
m["orgname"] = trimValue(netname)
}
return m
}
// Send request to a server and receive the response
func (w *Whois) query(target string, serverAddr string) (string, error) {
addr, _, _ := net.SplitHostPort(serverAddr)
if addr == "whois.arin.net" {
target = "n + " + target
}
conn, err := net.DialTimeout("tcp", serverAddr, time.Duration(w.timeoutMsec)*time.Millisecond)
if err != nil {
return "", err
}
defer conn.Close()
_ = conn.SetReadDeadline(time.Now().Add(time.Duration(w.timeoutMsec) * time.Millisecond))
_, err = conn.Write([]byte(target + "\r\n"))
if err != nil {
return "", err
}
data, err := ioutil.ReadAll(conn)
if err != nil {
return "", err
}
return string(data), nil
}
// Query WHOIS servers (handle redirects)
func (w *Whois) queryAll(target string) (string, error) {
server := net.JoinHostPort(defaultServer, defaultPort)
const maxRedirects = 5
for i := 0; i != maxRedirects; i++ {
resp, err := w.query(target, server)
if err != nil {
return "", err
}
log.Debug("Whois: received response (%d bytes) from %s IP:%s", len(resp), server, target)
m := whoisParse(resp)
redir, ok := m["whois"]
if !ok {
return resp, nil
}
redir = strings.ToLower(redir)
_, _, err = net.SplitHostPort(redir)
if err != nil {
server = net.JoinHostPort(redir, defaultPort)
} else {
server = redir
}
log.Debug("Whois: redirected to %s IP:%s", redir, target)
}
return "", fmt.Errorf("Whois: redirect loop")
}
// Request WHOIS information
func (w *Whois) process(ip string) [][]string {
data := [][]string{}
resp, err := w.queryAll(ip)
if err != nil {
log.Debug("Whois: error: %s IP:%s", err, ip)
return data
}
log.Debug("Whois: IP:%s response: %d bytes", ip, len(resp))
m := whoisParse(resp)
keys := []string{"orgname", "country", "city"}
for _, k := range keys {
v, found := m[k]
if !found {
continue
}
pair := []string{k, v}
data = append(data, pair)
}
return data
}
// Begin - begin requesting WHOIS info
func (w *Whois) Begin(ip string) {
now := uint64(time.Now().Unix())
expire := w.ipAddrs.Get([]byte(ip))
if len(expire) != 0 {
exp := binary.BigEndian.Uint64(expire)
if exp > now {
return
}
// TTL expired
}
expire = make([]byte, 8)
binary.BigEndian.PutUint64(expire, now+whoisTTL)
_ = w.ipAddrs.Set([]byte(ip), expire)
log.Debug("Whois: adding %s", ip)
select {
case w.ipChan <- ip:
//
default:
log.Debug("Whois: queue is full")
}
}
// Get IP address from channel; get WHOIS info; associate info with a client
func (w *Whois) workerLoop() {
for {
var ip string
ip = <-w.ipChan
info := w.process(ip)
if len(info) == 0 {
continue
}
w.clients.SetWhoisInfo(ip, info)
}
}