package home import ( "context" "encoding/binary" "fmt" "io/ioutil" "net" "strings" "time" "github.com/AdguardTeam/AdGuardHome/internal/aghio" "github.com/AdguardTeam/AdGuardHome/internal/aghstrings" "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 net.IP // 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 // TODO(a.garipov): Rewrite to use time.Duration. Like, seriously, why? timeoutMsec uint } // initWhois creates the Whois module context. func initWhois(clients *clientsContainer) *Whois { w := Whois{ timeoutMsec: 5000, clients: clients, ipAddrs: cache.New(cache.Config{ EnableLRU: true, MaxCount: 10000, }), ipChan: make(chan net.IP, 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 := aghstrings.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 "city", "country", "orgname": 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://"):] } } } _, ok := m["orgname"] if !ok { // Set orgname from either descr or netname for the frontent. // // TODO(a.garipov): Perhaps don't do that in the V1 HTTP API? if descr != "" { m["orgname"] = trimValue(descr) } else if netname != "" { m["orgname"] = trimValue(netname) } } return m } // MaxConnReadSize is an upper limit in bytes for reading from net.Conn. const MaxConnReadSize = 64 * 1024 // Send request to a server and receive the response func (w *Whois) query(ctx context.Context, target, serverAddr string) (string, error) { addr, _, _ := net.SplitHostPort(serverAddr) if addr == "whois.arin.net" { target = "n + " + target } conn, err := customDialContext(ctx, "tcp", serverAddr) if err != nil { return "", err } defer conn.Close() connReadCloser, err := aghio.LimitReadCloser(conn, MaxConnReadSize) if err != nil { return "", err } defer connReadCloser.Close() _ = conn.SetReadDeadline(time.Now().Add(time.Duration(w.timeoutMsec) * time.Millisecond)) _, err = conn.Write([]byte(target + "\r\n")) if err != nil { return "", err } // This use of ReadAll is now safe, because we limited the conn Reader. data, err := ioutil.ReadAll(connReadCloser) if err != nil { return "", err } return string(data), nil } // Query WHOIS servers (handle redirects) func (w *Whois) queryAll(ctx context.Context, target string) (string, error) { server := net.JoinHostPort(defaultServer, defaultPort) const maxRedirects = 5 for i := 0; i != maxRedirects; i++ { resp, err := w.query(ctx, 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(ctx context.Context, ip net.IP) (wi *RuntimeClientWhoisInfo) { resp, err := w.queryAll(ctx, ip.String()) if err != nil { log.Debug("Whois: error: %s IP:%s", err, ip) return nil } log.Debug("Whois: IP:%s response: %d bytes", ip, len(resp)) m := whoisParse(resp) wi = &RuntimeClientWhoisInfo{ City: m["city"], Country: m["country"], Orgname: m["orgname"], } // Don't return an empty struct so that the frontend doesn't get // confused. if *wi == (RuntimeClientWhoisInfo{}) { return nil } return wi } // Begin - begin requesting WHOIS info func (w *Whois) Begin(ip net.IP) { 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") } } // workerLoop processes the IP addresses it got from the channel and associates // the retrieving WHOIS info with a client. func (w *Whois) workerLoop() { for ip := range w.ipChan { info := w.process(context.Background(), ip) if info == nil { continue } id := ip.String() w.clients.SetWhoisInfo(id, info) } }