fix: try utp connection first; fix utp timeout issues. (#4897)

libtransmission/handshake.cc

@@ -792,6 +792,7 @@ void tr_handshake::on_error(tr_peerIo* io, tr_error const& error, void* vhandsha
             handshake->have_sent_bittorrent_handshake_ = true;
             handshake->set_state(State::AwaitingHandshake);
             io->write_bytes(std::data(msg), std::size(msg), false);
+            return;
         }
     }
 
@@ -807,12 +808,11 @@ void tr_handshake::on_error(tr_peerIo* io, tr_error const& error, void* vhandsha
         handshake->have_sent_bittorrent_handshake_ = true;
         handshake->set_state(State::AwaitingHandshake);
         io->write_bytes(std::data(msg), std::size(msg), false);
+        return;
     }
-    else
-    {
-        tr_logAddTraceHand(handshake, fmt::format("handshake socket err: {:s} ({:d})", error.message, error.code));
-        handshake->done(false);
-    }
+
+    tr_logAddTraceHand(handshake, fmt::format("handshake socket err: {:s} ({:d})", error.message, error.code));
+    handshake->done(false);
 }
 
 bool tr_handshake::fire_done(bool is_connected)

libtransmission/peer-io.cc

@@ -130,15 +130,7 @@ std::shared_ptr<tr_peerIo> tr_peerIo::new_outgoing(
 
     auto peer_io = tr_peerIo::create(session, parent, &info_hash, false, is_seed);
 
-    // try a TCP socket
-    if (auto sock = tr_netOpenPeerSocket(session, addr, port, is_seed); sock.is_valid())
-    {
-        peer_io->set_socket(std::move(sock));
-        return peer_io;
-    }
-
 #ifdef WITH_UTP
-    // try a UTP socket
     if (utp)
     {
         auto* const sock = utp_create_socket(session->utp_context);
@@ -153,6 +145,15 @@ std::shared_ptr<tr_peerIo> tr_peerIo::new_outgoing(
     }
 #endif
 
+    if (!peer_io->socket_.is_valid())
+    {
+        if (auto sock = tr_netOpenPeerSocket(session, addr, port, is_seed); sock.is_valid())
+        {
+            peer_io->set_socket(std::move(sock));
+            return peer_io;
+        }
+    }
+
     return {};
 }
 
@@ -677,13 +678,28 @@ void tr_peerIo::on_utp_error(int errcode)
 {
     tr_logAddTraceIo(this, fmt::format("utp_on_error -- {}", utp_error_code_names[errcode]));
 
-    if (got_error_ != nullptr)
+    if (got_error_ == nullptr)
     {
-        tr_error* error = nullptr;
-        tr_error_set(&error, errcode, utp_error_code_names[errcode]);
-        call_error_callback(*error);
-        tr_error_clear(&error);
+        return;
     }
+
+    tr_error* error = nullptr;
+    switch (errcode)
+    {
+    case UTP_ECONNREFUSED:
+        tr_error_set_from_errno(&error, ECONNREFUSED);
+        break;
+    case UTP_ECONNRESET:
+        tr_error_set_from_errno(&error, ECONNRESET);
+        break;
+    case UTP_ETIMEDOUT:
+        tr_error_set_from_errno(&error, ETIMEDOUT);
+        break;
+    default:
+        tr_error_set(&error, errcode, utp_error_code_names[errcode]);
+    }
+    call_error_callback(*error);
+    tr_error_clear(&error);
 }
 
 #endif /* #ifdef WITH_UTP */

libtransmission/tr-utp.cc

@@ -141,7 +141,7 @@ uint64 utp_callback(utp_callback_arguments* args)
     return 0;
 }
 
-void reset_timer(tr_session* session)
+void restart_timer(tr_session* session)
 {
     auto interval = std::chrono::milliseconds{};
     auto const random_percent = tr_rand_int(1000U) / 1000.0;
@@ -177,7 +177,7 @@ void timer_callback(void* vsession)
     utp_issue_deferred_acks(session->utp_context);
 
     utp_check_timeouts(session->utp_context);
-    reset_timer(session);
+    restart_timer(session);
 }
 } // namespace
 
@@ -208,16 +208,12 @@ void tr_utpInit(tr_session* session)
 #endif
 
     session->utp_context = ctx;
+    session->utp_timer = session->timerMaker().create(timer_callback, session);
+    restart_timer(session);
 }
 
 bool tr_utpPacket(unsigned char const* buf, size_t buflen, struct sockaddr const* from, socklen_t fromlen, tr_session* ss)
 {
-    if (!ss->isClosing() && !ss->utp_timer)
-    {
-        ss->utp_timer = ss->timerMaker().create(timer_callback, ss);
-        reset_timer(ss);
-    }
-
     auto const ret = utp_process_udp(ss->utp_context, buf, buflen, from, fromlen);
 
     /* utp_internal.cpp says "Should be called each time the UDP socket is drained" but it's tricky with libevent */