From 8664daeb9a2ed7bc9016c29c38cac7a061c6177c Mon Sep 17 00:00:00 2001
From: Thulinma <jaron@vietors.com>
Date: Fri, 17 May 2024 14:53:55 +0200
Subject: [PATCH] Improve and robustify local UDP port handling

---
 lib/defines.h                     |  9 ---------
 src/controller/controller_api.cpp | 25 +++++++++++++++++++++----
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/lib/defines.h b/lib/defines.h
index 905d1a19..28b2b070 100644
--- a/lib/defines.h
+++ b/lib/defines.h
@@ -260,15 +260,6 @@ static inline void show_stackframe(){}
 
 #define SIMUL_TRACKS 40
 
-#ifndef UDP_API_HOST
-#define UDP_API_HOST "localhost"
-#endif
-
-#ifndef UDP_API_PORT
-#define UDP_API_PORT 4242
-#endif
-
-
 // The amount of milliseconds a simulated live stream is allowed to be "behind".
 // Setting this value to lower than 2 seconds **WILL** cause stuttering in playback due to buffer negotiation.
 #define SIMULATED_LIVE_BUFFER 7000
diff --git a/src/controller/controller_api.cpp b/src/controller/controller_api.cpp
index 0d40c284..f46e1083 100644
--- a/src/controller/controller_api.cpp
+++ b/src/controller/controller_api.cpp
@@ -452,10 +452,27 @@ int Controller::handleAPIConnection(Socket::Connection &conn){
 
 void Controller::handleUDPAPI(void *np){
   Socket::UDPConnection uSock(true);
-  uint16_t boundPort = uSock.bind(UDP_API_PORT, UDP_API_HOST);
-  if (!boundPort){
-    FAIL_MSG("Could not open local API UDP socket - not all functionality will be available");
-    return;
+  uint16_t boundPort;
+  {
+    HTTP::URL udpApiAddr("udp://localhost:4242");
+    if (getenv("UDP_API")){udpApiAddr = HTTP::URL(getenv("UDP_API"));}
+    boundPort = uSock.bind(udpApiAddr.getPort(), udpApiAddr.host);
+    if (!boundPort){
+      FAIL_MSG("Could not open local UDP API socket on %s:%" PRIu16 " - retrying with an ephemeral port", udpApiAddr.host.c_str(), udpApiAddr.getPort());
+      boundPort = uSock.bind(0, udpApiAddr.host);
+      if (!boundPort){
+        std::stringstream newHost;
+        char ranNums[3];
+        Util::getRandomBytes(ranNums, 3);
+        newHost << "127." << (int)ranNums[0] << "." << (int)ranNums[1] << "." << (int)ranNums[2];
+        FAIL_MSG("Could not open local ephemeral UDP API socket either - retrying with host %s", newHost.str().c_str());
+        boundPort = uSock.bind(0, newHost.str());
+        if (!boundPort){
+          FAIL_MSG("Could not open local UDP API socket even after all that... disabling local UDP API, some functionality may not be available");
+          return;
+        }
+      }
+    }
   }
   HTTP::URL boundAddr;
   boundAddr.protocol = "udp";