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Demostrate rust example tun operation and tcp handshake on tun channel by studying following stream.

code based on following lecture:
youtube https://www.youtube.com/watch?v=bzja9fQWzdA
code https://github.com/jonhoo/rust-tcp

run in docker

Tips&Notes

docker build -t corbamico/rust:1.34 .
docker run -v /c/project/rust/docker:/home/rust -w /home/rust --cap-add=NET_ADMIN --device=/dev/net/tun -it corbamico/rust:1.34 /bin/bash
docker exec -it 678f26b3a034 -u 0:0 /bin/bash

run vscode inside docker

for windows 10, install VcXsrv

docker run --rm -v /c/project/rust/docker:/home/rust -w /home/rust/tun_libtcp --privileged --cap-add=NET_ADMIN --device=/dev/net/tun --env DISPLAY=10.0.75.1:0.0 corbamico/rust:vscode code --wait --diable-updates --user-data-dir=/var/run/code .

• --privileged
  vscode need dbus

• --wait vscode need xclient link to x-server

• --user-data-dir see refence microsoft/vscode#28126

tips for attach shell from cmd.exe

create fish.bat file as:

@pwsh -c "& {$cid=docker ps -q ; docker exec -it $cid.trim() /usr/bin/fish}"

Steps

Step1

• Description

  Print tun data bytes and headers

• how to run

  cargo run --bin libtcp_step1 &
ping -I tun0 10.0.0.5

Step2

• Description

  implement ICMP echo (ping).

• example ping packet

  packet :[69, 0, 0, 36, 3, 119, 64, 0, 64, 1, 35, 93, 10, 0, 0, 1, 10, 0, 0, 5, 8, 0, 232, 126, 3, 112, 0, 1, 0, 1, 2, 3, 4, 5, 6, 7]

• how to run

  cargo run --bin libtcp_step2 &
ping -I tun0 10.0.0.100

Step3

• Description

  implement TCP server syn/fin packet, and tcp server feedback fix "hello\n"

• how to run

  open 3 shells run following separately

  cargo run --bin libtcp_step3
tshark -i tun0
nc -s 10.0.0.1 10.0.0.5 8000

• tshark capture as

  1 0.000000000     10.0.0.1 ? 10.0.0.5     TCP 60 34255 ? 8000 [SYN] Seq=0 Win=29200 Len=0 MSS=1460 SACK_PERM=1 TSval=4953968 TSecr=0 WS=128
  2 0.000076200     10.0.0.5 ? 10.0.0.1     TCP 40 8000 ? 34255 [SYN, ACK] Seq=0 Ack=1 Win=1024 Len=0
  3 0.000120800     10.0.0.1 ? 10.0.0.5     TCP 40 34255 ? 8000 [ACK] Seq=1 Ack=1 Win=29200 Len=0
  4 4.393103500     10.0.0.1 ? 10.0.0.5     TCP 47 34255 ? 8000 [PSH, ACK] Seq=1 Ack=1 Win=29200 Len=7
  5 4.393153200     10.0.0.5 ? 10.0.0.1     TCP 42 8000 ? 34255 [ACK] Seq=1 Ack=8 Win=1024 Len=2
  6 4.393166700     10.0.0.1 ? 10.0.0.5     TCP 40 34255 ? 8000 [ACK] Seq=8 Ack=3 Win=29200 Len=0
  7 7.228395400     10.0.0.1 ? 10.0.0.5     TCP 40 34255 ? 8000 [FIN, ACK] Seq=8 Ack=3 Win=29200 Len=0
  8 7.228515200     10.0.0.5 ? 10.0.0.1     TCP 40 8000 ? 34255 [FIN, ACK] Seq=3 Ack=9 Win=1024 Len=0
  9 7.228565900     10.0.0.1 ? 10.0.0.5     TCP 40 34255 ? 8000 [ACK] Seq=9 Ack=4 Win=29200 Len=0

Step4

• Description

  Combine function of step2(icmp ping) and step4(tcp server) using futures::future::Either.

          ...
          FramedRead::new(rd, BytesCodec::new())
          .filter_map(|bytes| {
              let tcpcon = Self::filter_with_tcp(&bytes).map(Either::A);
              let icmpbytes = Self::filter_with_icmp(bytes).map(Either::B);
              tcpcon.or(icmpbytes)
          })
          .map(|con_or_bytes| {
              match con_or_bytes{
                  Either::A(con) => Self::gen_tcp_packet(con),
                  Either::B(bytes) => Self::gen_ping_echo(bytes),
              }
          })
          .forward(writer)
          ...

Step5

• Description

  implement ping via mpsc.

Step6

• Description

  1.implement background process via reader-future and writer-future.
  2.as application-level, empty "demo tcp server fn tcp_srv()" use libtcp as tcp stack. 3.can accept multi tcp client on one tcp server, but does not implement tcpstream.

Step6

• Description 1.re-work Step6 avoid static Libtcp

Step7

• Description 1.Deal with TCP.State LastAck,Closed while recive FIN 2.Demo TCP Server for Connect/Read from Client/Closed from Client

  1 0.000000000     10.0.0.1 ? 10.0.0.5     TCP 60 46017 ? 8000 [SYN] Seq=0 Win=29200 Len=0 MSS=1460 SACK_PERM=1 TSval=2216703 TSecr=0 WS=128
  2 0.000046100     10.0.0.5 ? 10.0.0.1     TCP 40 8000 ? 46017 [SYN, ACK] Seq=0 Ack=1 Win=1024 Len=0
  3 0.000080200     10.0.0.1 ? 10.0.0.5     TCP 40 46017 ? 8000 [ACK] Seq=1 Ack=1 Win=29200 Len=0
  4 1.707420800     10.0.0.1 ? 10.0.0.5     TCP 42 46017 ? 8000 [PSH, ACK] Seq=1 Ack=1 Win=29200 Len=2
  5 1.707567700     10.0.0.5 ? 10.0.0.1     TCP 40 8000 ? 46017 [ACK] Seq=1 Ack=3 Win=1024 Len=0
  6 2.366750100     10.0.0.1 ? 10.0.0.5     TCP 43 46017 ? 8000 [PSH, ACK] Seq=3 Ack=1 Win=29200 Len=3
  7 2.366860000     10.0.0.5 ? 10.0.0.1     TCP 40 8000 ? 46017 [ACK] Seq=1 Ack=6 Win=1024 Len=0
  8 2.877136600     10.0.0.1 ? 10.0.0.5     TCP 42 46017 ? 8000 [PSH, ACK] Seq=6 Ack=1 Win=29200 Len=2
  9 2.877204400     10.0.0.5 ? 10.0.0.1     TCP 40 8000 ? 46017 [ACK] Seq=1 Ack=8 Win=1024 Len=0
  10 7.182180400     10.0.0.1 ? 10.0.0.5     TCP 40 46017 ? 8000 [FIN, ACK] Seq=8 Ack=1 Win=29200 Len=0
  11 7.182287800     10.0.0.5 ? 10.0.0.1     TCP 40 8000 ? 46017 [FIN, ACK] Seq=1 Ack=9 Win=1024 Len=0
  12 7.182303500     10.0.0.1 ? 10.0.0.5     TCP 40 46017 ? 8000 [ACK] Seq=9 Ack=2 Win=29200 Len=0