From 7f40ab0082af65aa3041acf0d3c1e92e4f4021c7 Mon Sep 17 00:00:00 2001
From: Christian Ulrich <christian@ulrich.earth>
Date: Wed, 29 Jul 2020 20:15:01 +0200
Subject: [PATCH] source port may take a bit to become available again, so
 retry binding three times

---
 examples/app/app.nim | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/examples/app/app.nim b/examples/app/app.nim
index 361a2fb..114c239 100644
--- a/examples/app/app.nim
+++ b/examples/app/app.nim
@@ -166,10 +166,18 @@ proc punchHole(punchdConn: PunchdConnection, serverConn: ServerConnection,
 
 proc initServerConnection(serverHostname: string, serverPort: Port,
                           probingPort: Port): Future[ServerConnection] {.async.} =
-  for i in 0 .. 1:
+  var failCount = 0
+  while result.probedPorts.len < 2:
     # FIXME: error handling
     let sock = newAsyncSocket()
-    sock.bindAddr(probingPort)
+    try:
+      sock.bindAddr(probingPort)
+    except OSError as e:
+      if failCount == 3:
+        raise e
+      failCount.inc
+      await sleepAsync(1000)
+      continue
     await sock.connect(serverHostname, serverPort)
     let id = rand(uint32)
     await sock.send(&"get-endpoint|{id}\n")