pandax381 / microps

An implementation of a small TCP/IP protocol stack for learning.

microps

microps is an implementation of a small TCP/IP protocol stack for learning.

• If you love the Go language: https://github.com/pandax381/lectcp
• Porting to xv6: https://github.com/pandax381/xv6-net
• Porting to MikanOS: https://github.com/pandax381/mikanos-net

Documents

• Step by Step Development Guides (Japanese)

Features

Abstraction Layer

• Physical device abstraction
  • Define structure for physical device abstraction (struct net_device)
  • Support multiple link protocols and physical devices
• Logical interface abstraction
  • Define structure for logical interface abstraction (struct net_iface)
  • Support multiple address family and logical interfaces

Devices

• Null
• Loopback
• Ethernet
  • TUN/TAP (Linux)
  • PF_PACKET (Linux)

Protocols

• Ethernet
• ARP
• IP
• ICMP
• UDP
• TCP

API

• Socket like API

Logs

18:43:46.153 [I] net_protocol_register: registerd, type=ARP(0x0806) (net.c:223)
18:43:46.153 [I] net_timer_register: registerd: ARP Timer interval={1, 0} (net.c:257)
18:43:46.153 [I] net_protocol_register: registerd, type=IP(0x0800) (net.c:223)
18:43:46.153 [I] ip_protocol_register: registerd, type=ICMP(0x01) (ip.c:440)
18:43:46.153 [I] ip_protocol_register: registerd, type=UDP(0x11) (ip.c:440)
18:43:46.153 [I] ip_protocol_register: registerd, type=TCP(0x06) (ip.c:440)
18:43:46.153 [I] net_timer_register: registerd: TCP Timer interval={0, 100000} (net.c:257)
18:43:46.153 [I] net_device_register: registerd, dev=net0, type=0x0000 (net.c:74)
18:43:46.153 [D] null_init: initialized, dev=net0 (driver/null.c:46)
18:43:46.153 [I] net_device_register: registerd, dev=net1, type=0x0001 (net.c:74)
18:43:46.153 [D] loopback_init: initialized, dev=net1 (driver/loopback.c:49)
18:43:46.153 [I] ip_route_add: network=127.0.0.0, netmask=255.0.0.0, nexthop=0.0.0.0, iface=127.0.0.1 dev=net1 (ip.c:136)
18:43:46.153 [I] ip_iface_register: registerd: dev=net1, unicast=127.0.0.1, netmask=127.0.0.1, broadcast=255.0.0.0 (ip.c:233)
18:43:46.153 [I] net_device_register: registerd, dev=net2, type=0x0002 (net.c:74)
18:43:46.153 [D] ether_tap_init: ethernet device initialized, dev=net2 (driver/ether_tap_linux.c:174)
18:43:46.153 [I] ip_route_add: network=192.0.2.0, netmask=255.255.255.0, nexthop=0.0.0.0, iface=192.0.2.2 dev=net2 (ip.c:136)
18:43:46.153 [I] ip_iface_register: registerd: dev=net2, unicast=192.0.2.2, netmask=192.0.2.2, broadcast=255.255.255.0 (ip.c:233)
18:43:46.153 [I] ip_route_add: network=0.0.0.0, netmask=0.0.0.0, nexthop=192.0.2.1, iface=192.0.2.2 dev=net2 (ip.c:136)
18:43:46.153 [D] net_run: open all devices... (net.c:314)
18:43:46.153 [I] net_device_open: dev=net2, state=up (net.c:92)
18:43:46.153 [I] net_device_open: dev=net1, state=up (net.c:92)
18:43:46.153 [I] net_device_open: dev=net0, state=up (net.c:92)
18:43:46.153 [D] net_run: create background thread... (net.c:318)
18:43:46.154 [D] net_run: running... (net.c:324)
18:43:57.931 [D] ether_poll_helper: dev=net2, type=ARP(0x0806), len=42 (ether.c:127)
        src: 0e:4e:af:bc:64:c6
        dst: ff:ff:ff:ff:ff:ff
       type: 0x0806 (ARP)
18:43:57.931 [D] net_input_handler: queue pushed (num:1), dev=net2, type=ARP(0x0806), len=28 (net.c:191)
18:43:57.931 [D] net_thread: queue poped (num:0), dev=net2, type=ARP(0x0806), len=28 (net.c:286)
18:43:57.931 [D] arp_input: dev=net2, opcode=Request(0x0001), len=28 (arp.c:239)
        hrd: 0x0001
        pro: 0x0800
        hln: 6
        pln: 4
         op: 0x0001 (Request)
        sha: 0e:4e:af:bc:64:c6
        spa: 192.0.2.1
        tha: 00:00:00:00:00:00
        tpa: 192.0.2.2
18:43:57.931 [D] arp_cache_insert: INSERT: pa=192.0.2.1, ha=0e:4e:af:bc:64:c6 (arp.c:163)
18:43:57.931 [D] arp_reply: dev=net2, opcode=Reply(0x0002), len=28 (arp.c:213)
        hrd: 0x0001
        pro: 0x0800
        hln: 6
        pln: 4
         op: 0x0002 (Reply)
        sha: 00:00:5e:00:53:01
        spa: 192.0.2.2
        tha: 0e:4e:af:bc:64:c6
        tpa: 192.0.2.1
18:43:57.931 [D] net_device_output: dev=net2, type=ARP(0x0806), len=28 (net.c:156)
18:43:57.931 [D] ether_transmit_helper: dev=net2, type=ARP(0x0806), len=60 (ether.c:101)
        src: 00:00:5e:00:53:01
        dst: 0e:4e:af:bc:64:c6
       type: 0x0806 (ARP)
18:43:57.931 [D] ether_poll_helper: dev=net2, type=IP(0x0800), len=98 (ether.c:127)
        src: 0e:4e:af:bc:64:c6
        dst: 00:00:5e:00:53:01
       type: 0x0800 (IP)
18:43:57.931 [D] net_input_handler: queue pushed (num:1), dev=net2, type=IP(0x0800), len=84 (net.c:191)
18:43:57.932 [D] net_thread: queue poped (num:0), dev=net2, type=IP(0x0800), len=84 (net.c:286)
18:43:57.932 [D] ip_input: dev=net2, iface=192.0.2.2, protocol=ICMP(0x01), len=84 (ip.c:303)
        vhl: 0x45 [v: 4, hl: 5 (20)]
        tos: 0x00
      total: 84 (payload: 64)
         id: 41026
     offset: 0x4000 [flags=2, offset=0]
        ttl: 64
   protocol: 1 (ICMP)
        sum: 0x1663 (0x1663)
        src: 192.0.2.1
        dst: 192.0.2.2
18:43:57.932 [D] icmp_input: 192.0.2.1 => 192.0.2.2, type=Echo(8), len=64, iface=192.0.2.2 (icmp.c:100)
       type: 8 (Echo)
       code: 0
        sum: 0xb692 (0xb692)
         id: 55
        seq: 1
18:43:57.932 [D] icmp_output: 192.0.2.2 => 192.0.2.1, type=EchoReply(0), len=64 (icmp.c:138)
       type: 0 (EchoReply)
       code: 0
        sum: 0xbe92 (0xbe92)
         id: 55
        seq: 1
18:43:57.932 [D] ip_output_core: dev=net2, iface=192.0.2.1, protocol=ICMP(0x01), len=84 (ip.c:357)
        vhl: 0x45 [v: 4, hl: 5 (20)]
        tos: 0x00
      total: 84 (payload: 64)
         id: 128
     offset: 0x0000 [flags=0, offset=0]
        ttl: 255
   protocol: 1 (ICMP)
        sum: 0x3725 (0x3725)
        src: 192.0.2.2
        dst: 192.0.2.1
18:43:57.932 [D] arp_resolve: resolved, pa=192.0.2.1, ha=0e:4e:af:bc:64:c6 (arp.c:301)
18:43:57.932 [D] net_device_output: dev=net2, type=IP(0x0800), len=84 (net.c:156)
18:43:57.932 [D] ether_transmit_helper: dev=net2, type=IP(0x0800), len=98 (ether.c:101)
        src: 00:00:5e:00:53:01
        dst: 0e:4e:af:bc:64:c6
       type: 0x0800 (IP)
^C18:44:01.605 [D] net_shutdown: terminate background thread... (net.c:334)
18:44:01.606 [D] net_shutdown: close all devices... (net.c:341)
18:44:01.606 [I] net_device_close: dev=net2, state=down (net.c:110)
18:44:01.606 [I] net_device_close: dev=net1, state=down (net.c:110)
18:44:01.606 [I] net_device_close: dev=net0, state=down (net.c:110)
18:44:01.606 [D] net_shutdown: shutdown (net.c:345)

Tutorial

1. Build

$ git clone [email protected]:pandax381/microps.git
$ cd microps
$ make

2. Prepare Tap device

$ sudo ip tuntap add mode tap user $USER name tap0
$ sudo ip addr add 192.0.2.1/24 dev tap0
$ sudo ip link set tap0 up

It is temporary and will disappear after reboot.

3. Run sample application

$ ./app/tcps.exe 7
11:48:55.884 [I] net_protocol_register: registerd, type=ARP(0x0806) (net.c:223)
11:48:55.884 [I] net_timer_register: registerd: ARP Timer interval={1, 0} (net.c:257)
11:48:55.884 [I] net_protocol_register: registerd, type=IP(0x0800) (net.c:223)
...
11:48:55.884 [D] net_run: running... (net.c:324)
11:48:55.884 [D] tcp_bind: success: addr=0.0.0.0, port=7 (tcp.c:1156)

TCP Echo Server start on port 7. (default address is 192.0.2.2/24)

4. Test (Operate in another terminal)

• Ping

$ ping 192.0.2.2
PING 192.0.2.2 (192.0.2.2) 56(84) bytes of data.
64 bytes from 192.0.2.2: icmp_seq=1 ttl=255 time=0.660 ms
64 bytes from 192.0.2.2: icmp_seq=2 ttl=255 time=0.688 ms
64 bytes from 192.0.2.2: icmp_seq=3 ttl=255 time=0.574 ms
...

• TCP communication

$ nc 192.0.2.2 7
foo
foo
bar
bar

Sending text will be sent back by the Echo Server.

License

microps is under the MIT License: See LICENSE file.

microps's Issues

out_of_order

hello, i want to know that this project is supported out_of_order packet for tcp?

TCPC running against TCPS

The tcps example from the README.md works fine, now I'm wondering what would be neede to use the tcpc client against the tcps server. Could you provide an simple example on how to use ... are there multiple tap devices needed?

tcp_cb の再利用のバグ

tcp_cb は cb->used が 0 の時に新しいソケットとして再利用される。

しかし、cb->txq の中身はクリアされていないため、前のソケットの時に追加されたパケットがタイムアウトして再送されてしまう。

cb->state が TCP_CB_STATE_CLOSED になった時に cb->txq の中身を全て削除するような終了処理を追加する必要がある。

global var socks and tcp_pcb pcbs

i found that ths socks's len is 128 and , tcp_pcbs'len is 16, so is the tcp_pcb's len is small and socks var'len is too big. Should they be equal.
And we use array index to associate this 2 variables. can we use list or other to associate this 2 var, so that we can use more fd ,

Microps

Any chance to provide English documentation?

I am keen to translate by Google, but still some difficulty to understand the design.