From ef68519eecaae39b24f6c7a02b145b313f707e88 Mon Sep 17 00:00:00 2001
From: Christian Ulrich <christian@ulrich.earth>
Date: Sat, 18 Jul 2020 13:06:22 +0200
Subject: [PATCH] fix 'invalid argument' by using a separate socket for
 listening

---
 tcp_syni.nim | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tcp_syni.nim b/tcp_syni.nim
index 707dad0..de9c676 100644
--- a/tcp_syni.nim
+++ b/tcp_syni.nim
@@ -133,8 +133,8 @@ proc doConnect(srcIp: IpAddress, srcPort: Port, dstIp: IpAddress,
 
 proc doAccept(srcIp: IpAddress, srcPort: Port, dstIp: IpAddress, dstPort: Port,
               seqNums: seq[uint32], future: Future[AsyncSocket]) {.async.} =
-  let sock = newAsyncSocket()
   try:
+    let sock = newAsyncSocket()
     sock.setSockOpt(OptReuseAddr, true)
     sock.getFd.setSockOptInt(IPPROTO_IP, IP_TTL, 2)
     sock.bindAddr(srcPort, $srcIp)
@@ -144,9 +144,14 @@ proc doAccept(srcIp: IpAddress, srcPort: Port, dstIp: IpAddress, dstPort: Port,
   except OSError:
     discard
   try:
+    # FIXME: timeout
     let rawFd = setupTcpInjectingSocket()
     asyncCheck injectSyns(rawFd, dstIp, dstPort, srcIp, srcPort, seqNums)
-    sock.getFd.setSockOptInt(IPPROTO_IP, IP_TTL, 64)
+    let sock = newAsyncSocket()
+    sock.setSockOpt(OptReuseAddr, true)
+    sock.setSockOpt(OptReusePort, true)
+    sock.bindAddr(srcPort, $srcIp)
+    sock.listen()
     let connectedSock = await sock.accept()
     future.complete(connectedSock)
   except OSError as e: