From 7bc90f02b80e763e902bb1c730b72f8c521af147 Mon Sep 17 00:00:00 2001
From: Christian Ulrich <christian@ulrich.earth>
Date: Sun, 23 Aug 2020 15:52:50 +0200
Subject: [PATCH] need a second socket for injecting

---
 tcp_syni.nim | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/tcp_syni.nim b/tcp_syni.nim
index 4e51ac8..7413c49 100644
--- a/tcp_syni.nim
+++ b/tcp_syni.nim
@@ -56,7 +56,7 @@ proc injectTcpPacket(rawFd: AsyncFD, ipPacket: IpPacket) {.async.} =
                        cast[ptr SockAddr](addr sockaddr), sockaddrLen)
     echo &"injected {ipPacket.ipAddrSrc}:{ipPacket.tcpPortSrc.int} -> {ipPacket.ipAddrDst}:{ipPacket.tcpPortDst.int} (seq {ipPacket.tcpSeqNumber})"
   except OSError as e:
-    echo &"cannot inject {ipPacket.ipAddrSrc}:{ipPacket.tcpPortSrc.int} -> {ipPacket.ipAddrDst}:{ipPacket.tcpPortDst.int} (seq {ipPacket.tcpSeqNumber})", e.msg
+    echo &"cannot inject {ipPacket.ipAddrSrc}:{ipPacket.tcpPortSrc.int} -> {ipPacket.ipAddrDst}:{ipPacket.tcpPortDst.int} (seq {ipPacket.tcpSeqNumber}): ", e.msg
     raise newException(PunchHoleError, e.msg)
 
 proc captureSeqNumbers(puncher: TcpSyniPuncher, rawFd: AsyncFD,
@@ -80,9 +80,10 @@ proc captureSeqNumbers(puncher: TcpSyniPuncher, rawFd: AsyncFD,
           break
   await cb(seqNums)
 
-proc captureAndResendAck(puncher: TcpSyniPuncher, rawFd: AsyncFD) {.async.} =
+proc captureAndResendAck(puncher: TcpSyniPuncher, captureFd: AsyncFD,
+                         injectFd: AsyncFD) {.async.} =
   while true:
-    let packet = await rawFd.recv(4000)
+    let packet = await captureFd.recv(4000)
     if packet == "":
       break
     let parsed = parseEthernetPacket(packet)
@@ -101,7 +102,7 @@ proc captureAndResendAck(puncher: TcpSyniPuncher, rawFd: AsyncFD) {.async.} =
                                   tcpPortDst: parsed.tcpPortDst,
                                   tcpSeqNumber: parsed.tcpSeqNumber,
                                   tcpFlags: parsed.tcpFlags)
-          await rawFd.injectTcpPacket(ipPacket)
+          await injectFd.injectTcpPacket(ipPacket)
           break
 
 proc initPuncher*(srcPort: Port, dstIp: IpAddress, dstPorts: array[3, Port],
@@ -159,8 +160,9 @@ proc connect*(puncher: TcpSyniPuncher,
   let iface = fromIpAddress(puncher.srcIp)
   let captureSeqFd = setupEthernetCapturingSocket(iface)
   let captureAckFd = setupEthernetCapturingSocket(iface)
+  let injectAckFd = setupTcpInjectingSocket()
   asyncCheck puncher.captureSeqNumbers(captureSeqFd, progressCb)
-  asyncCheck puncher.captureAndResendAck(captureAckFd)
+  asyncCheck puncher.captureAndResendAck(captureAckFd, injectAckFd)
   await puncher.addFirewallRules()
   try:
     result = await puncher.connectParallel()