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refactor: create raw sockets where they are used

This commit is contained in:
Christian Ulrich 2020-10-10 12:30:14 +02:00
parent 9caca83dd6
commit 1116d06e82
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GPG Key ID: 8241BE099775A097
1 changed files with 33 additions and 33 deletions
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66
tcp_syni.nim
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@ -94,13 +94,13 @@ proc injectTcpPacket(rawFd: AsyncFD, ipPacket: IpPacket) {.async.} =
except OSError as e:
raise newException(PunchHoleError, e.msg)
proc captureSeqNumbers(attempt: ConnectAttempt, rawFd: AsyncFD,
cb: PunchProgressCb) {.async.} =
proc captureSeqNumbers(attempt: ConnectAttempt, cb: PunchProgressCb) {.async.} =
# FIXME: timeout?
# FIXME: create raw socket here
let iface = fromIpAddress(attempt.srcIp)
let captureFd = setupEthernetCapturingSocket(iface)
var seqNums = newSeq[uint32]()
while seqNums.len < attempt.dstPorts.len:
let packet = await rawFd.recv(4000)
let packet = await captureFd.recv(4000)
if packet == "":
break
let parsed = parseEthernetPacket(packet)
@ -113,12 +113,13 @@ proc captureSeqNumbers(attempt: ConnectAttempt, rawFd: AsyncFD,
if parsed.tcpPortDst.int == port.int:
seqNums.add(parsed.tcpSeqNumber)
break
closeSocket(rawFd)
closeSocket(captureFd)
await cb(seqNums)
proc captureAndResendAck(attempt: ConnectAttempt, captureFd: AsyncFD,
injectFd: AsyncFD) {.async.} =
# FIXME: create raw socket here
proc captureAndResendAck(attempt: ConnectAttempt) {.async.} =
let iface = fromIpAddress(attempt.srcIp)
let captureFd = setupEthernetCapturingSocket(iface)
let injectFd = setupTcpInjectingSocket()
block loops:
while true:
let packet = await captureFd.recv(4000)
@ -208,12 +209,8 @@ proc connect*(puncher: TcpSyniPuncher, srcPort: Port, dstIp: IpAddress,
dstPorts: predictPortRange(dstPorts))
puncher.connectAttempts.add(attempt)
await attempt.addFirewallRules()
let iface = fromIpAddress(attempt.srcIp)
let captureSeqFd = setupEthernetCapturingSocket(iface)
let captureAckFd = setupEthernetCapturingSocket(iface)
let injectAckFd = setupTcpInjectingSocket()
asyncCheck attempt.captureSeqNumbers(captureSeqFd, progressCb)
asyncCheck attempt.captureAndResendAck(captureAckFd, injectAckFd)
asyncCheck attempt.captureSeqNumbers(progressCb)
asyncCheck attempt.captureAndResendAck()
try:
let connectFuture = newFuture[AsyncSocket]("connect")
for dstPort in attempt.dstPorts:
@ -256,6 +253,27 @@ proc doAccept(puncher: TcpSyniPuncher, srcIp: IpAddress,
break
sock.close()
proc injectSynPackets(attempt: AcceptAttempt) {.async.} =
let rawFd = setupTcpInjectingSocket()
for dstPort in attempt.dstPorts:
let synOut = IpPacket(protocol: tcp, ipAddrSrc: attempt.srcIp,
ipAddrDst: attempt.dstIp, ipTTL: 2,
tcpPortSrc: attempt.srcPort, tcpPortDst: dstPort,
tcpSeqNumber: rand(uint32), tcpAckNumber: 0,
tcpFlags: {SYN}, tcpWindowSize: 1452 * 10)
echo &"[{synOut.ipAddrSrc}:{synOut.tcpPortSrc} -> {synOut.ipAddrDst}:{synOut.tcpPortDst}, SEQ {synOut.tcpSeqNumber}] injecting outgoing SYN"
await rawFd.injectTcpPacket(synOut)
for seqNum in attempt.seqNums:
let synIn = IpPacket(protocol: tcp, ipAddrSrc: attempt.dstIp,
ipAddrDst: attempt.srcIp, ipTTL: 64,
tcpPortSrc: dstPort,
tcpPortDst: attempt.srcPort,
tcpSeqNumber: seqNum, tcpAckNumber: 0,
tcpFlags: {SYN}, tcpWindowSize: 1452 * 10)
echo &"[{synIn.ipAddrSrc}:{synIn.tcpPortSrc} -> {synIn.ipAddrDst}:{synIn.tcpPortDst}, SEQ {synIn.tcpSeqNumber}] injecting incoming SYN"
await rawFd.injectTcpPacket(synIn)
closeSocket(rawFd)
proc accept*(puncher: TcpSyniPuncher, srcPort: Port, dstIp: IpAddress,
dstPorts: seq[Port],
seqNums: seq[uint32]): Future[AsyncSocket] {.async.} =
@ -270,31 +288,13 @@ proc accept*(puncher: TcpSyniPuncher, srcPort: Port, dstIp: IpAddress,
a.dstPorts.any(proc (p: Port): bool = p in dstPorts):
raise newException(PunchHoleError, "hole punching for given parameters already active")
try:
let rawFd = setupTcpInjectingSocket()
let attempt = AcceptAttempt(srcIp: localIp, srcPort: srcPort, dstIp: dstIp,
dstPorts: predictPortRange(dstPorts),
seqNums: seqNums,
future: newFuture[AsyncSocket]("accept"))
puncher.acceptAttempts.add(attempt)
await attempt.addFirewallRules()
for dstPort in attempt.dstPorts:
let synOut = IpPacket(protocol: tcp, ipAddrSrc: attempt.srcIp,
ipAddrDst: attempt.dstIp, ipTTL: 2,
tcpPortSrc: attempt.srcPort, tcpPortDst: dstPort,
tcpSeqNumber: rand(uint32), tcpAckNumber: 0,
tcpFlags: {SYN}, tcpWindowSize: 1452 * 10)
echo &"[{synOut.ipAddrSrc}:{synOut.tcpPortSrc} -> {synOut.ipAddrDst}:{synOut.tcpPortDst}, SEQ {synOut.tcpSeqNumber}] injecting outgoing SYN"
await rawFd.injectTcpPacket(synOut)
for seqNum in attempt.seqNums:
let synIn = IpPacket(protocol: tcp, ipAddrSrc: attempt.dstIp,
ipAddrDst: attempt.srcIp, ipTTL: 64,
tcpPortSrc: dstPort,
tcpPortDst: attempt.srcPort,
tcpSeqNumber: seqNum, tcpAckNumber: 0,
tcpFlags: {SYN}, tcpWindowSize: 1452 * 10)
echo &"[{synIn.ipAddrSrc}:{synIn.tcpPortSrc} -> {synIn.ipAddrDst}:{synIn.tcpPortDst}, SEQ {synIn.tcpSeqNumber}] injecting incoming SYN"
await rawFd.injectTcpPacket(synIn)
closeSocket(rawFd)
await attempt.injectSynPackets()
await attempt.future or sleepAsync(Timeout)
await attempt.deleteFirewallRules()
puncher.acceptAttempts.del(puncher.acceptAttempts.find(attempt))