Limit udp tracker server request concurrency

diff --git a/tracker/udp/server/server.go b/tracker/udp/server/server.go
index c686a23d27b8fd2cc96d2983b0a779ce7b74b814..6f0fb438e28a2e85e939d786edf224fffebcd776 100644 (file)
--- a/tracker/udp/server/server.go
+++ b/tracker/udp/server/server.go
@@ -206,13 +206,24 @@ func RunSimple(ctx context.Context, s *Server, pc net.PacketConn, family udp.Add
        ctx, cancel := context.WithCancel(ctx)
        defer cancel()
        var b [1500]byte
+       // Limit concurrent handled requests.
+       sem := make(chan struct{}, 1000)
        for {
                n, addr, err := pc.ReadFrom(b[:])
                if err != nil {
                        return err
                }
+               select {
+               case <-ctx.Done():
+                       return ctx.Err()
+               default:
+                       log.Printf("dropping request from %v: concurrency limit reached", addr)
+                       continue
+               case sem <- struct{}{}:
+               }
                b := append([]byte(nil), b[:n]...)
                go func() {
+                       defer func() { <-sem }()
                        err := s.HandleRequest(ctx, family, addr, b)
                        if err != nil {
                                log.Printf("error handling %v byte request from %v: %v", n, addr, err)