diff --git a/p2p/nat/nat_stun.go b/p2p/nat/nat_stun.go index 7277aa36e0..beaf1b1619 100644 --- a/p2p/nat/nat_stun.go +++ b/p2p/nat/nat_stun.go @@ -17,10 +17,13 @@ package nat import ( + "errors" "fmt" + "math/rand" "net" "time" + "github.com/ethereum/go-ethereum/log" stunV2 "github.com/pion/stun/v2" ) @@ -50,32 +53,28 @@ var stunDefaultServerList = []string{ const requestLimit = 3 type stun struct { - serverList []string - activeIndex int // the server index which return the IP - pendingRequests int // request in flight - askedIndex map[int]struct{} - replyCh chan stunResponse + serverList []string } func newSTUN(serverAddr string) (Interface, error) { - serverList := make([]string, 0) - if serverAddr == "default" { - serverList = stunDefaultServerList + s := new(stun) + if serverAddr == "default" || serverAddr == "" { + s.serverList = stunDefaultServerList } else { _, err := net.ResolveUDPAddr("udp4", serverAddr) if err != nil { return nil, err } - serverList = append(serverList, serverAddr) + s.serverList = []string{serverAddr} } - - return &stun{ - serverList: serverList, - }, nil + return s, nil } func (s stun) String() string { - return fmt.Sprintf("STUN(%s)", s.serverList[s.activeIndex]) + if len(s.serverList) == 1 { + return fmt.Sprintf("STUN(%s)", s.serverList[0]) + } + return "STUN" } func (stun) SupportsMapping() bool { @@ -90,50 +89,40 @@ func (stun) DeleteMapping(string, int, int) error { return nil } -type stunResponse struct { - ip net.IP - err error - index int -} - func (s *stun) ExternalIP() (net.IP, error) { - var err error - s.replyCh = make(chan stunResponse, requestLimit) - s.askedIndex = make(map[int]struct{}) - for s.startQueries() { - response := <-s.replyCh - s.pendingRequests-- - if response.err != nil { - err = response.err + for _, server := range s.randomServers(requestLimit) { + ip, err := s.externalIP(server) + if err != nil { + log.Debug("STUN request failed", "server", server, "err", err) continue } - s.activeIndex = response.index - return response.ip, nil + return ip, nil } - return nil, err + return nil, errors.New("STUN requests failed") } -func (s *stun) startQueries() bool { - for i := 0; s.pendingRequests < requestLimit && i < len(s.serverList); i++ { - _, exist := s.askedIndex[i] - if exist { +func (s *stun) randomServers(n int) []string { + n = min(n, len(s.serverList)) + m := make(map[int]struct{}, n) + list := make([]string, 0, n) + for i := 0; i < len(s.serverList)*2 && len(list) < n; i++ { + index := rand.Intn(len(s.serverList)) + if _, alreadyHit := m[index]; alreadyHit { continue } - s.pendingRequests++ - s.askedIndex[i] = struct{}{} - go func(index int, server string) { - ip, err := externalIP(server) - s.replyCh <- stunResponse{ - ip: ip, - index: index, - err: err, - } - }(i, s.serverList[i]) + list = append(list, s.serverList[index]) + m[index] = struct{}{} } - return s.pendingRequests > 0 + return list } -func externalIP(server string) (net.IP, error) { +func (s *stun) externalIP(server string) (net.IP, error) { + _, _, err := net.SplitHostPort(server) + if err != nil { + server += ":3478" + } + + log.Trace("Attempting STUN binding request", "server", server) conn, err := stunV2.Dial("udp4", server) if err != nil { return nil, err @@ -162,6 +151,6 @@ func externalIP(server string) (net.IP, error) { if responseError != nil { return nil, responseError } - + log.Trace("STUN returned IP", "server", server, "ip", mappedAddr.IP) return mappedAddr.IP, nil }