Nicolas Nackel / Mbed 2 deprecated PPP-Blinky

Small Internet Protocol Stack using a standard serial port.

Dependencies:   mbed

PPP-Blinky - TCP/IP Networking Over a Serial Port

Note: The source code is at the bottom of this page.

/media/uploads/nixnax/blinky-connected.gif
A Windows desktop showing PPP-Blinky in the network connections list.

Describe PPP-Blinky in Three Sentences

PPP-Blinky is a tiny library that enables Internet protocols (IPv4) to any mbed target hardware by using only a serial port.

The code runs on processors with as little as 8k RAM, for example the Nucleo-L053R8 board.

PPP-Blinky uses the industry-standard PPP (Point-to-Point) Protocol and a tiny "stateless" TCP/IP stack.

No Ethernet Port Required

No ethernet port is required - PPP-Blinky uses a serial port to send IP packets to your PC.

PPP-Blinky emulates a standard dial-up modem and therefore connects to Windows, Linux or Adroid machines.

The code runs on most ARM mbed platforms such as the LPC11U24 shown in the picture below:

/media/uploads/nixnax/blinky-to-laptop1.jpg mbed LPC11u24 acting as a webserver to a Windows laptop.

Webserver

The Webserver and WebSocket functions are ideal for building browser-based GUIs on mbed-enabled hardware.

PPP-Blinky's HTTP webserver works with most web clients such as Internet Explorer, Mozilla Firefox, Google Chrome, Safari, Curl, wget and Lynx as well as Microsoft Powershell Invoke-Webrequest command.

In the image below Firefox web browser displays the main web page embedded into PPP-Blinky's code:

/media/uploads/nixnax/ppp-blinky-firefox.jpg Firefox web browser displays a web page embedded into PPP-Blinky's code

WebSocket Service

WebSocket is the most popular protocol standard for real-time bidirectional TCP/IP communication between clients and servers.
In the image below a small Internet Explorer script has connected to PPP-Blinky's WebSocket Service.
A websocket message was then sent by the browser and was echoed back by the WebSocket, triggering the onmessage event in the script.
The WebSocket service enables bidirectional real-time interaction between PPP-Blinky and any element in the browser DOM via JavaScript.
If you already have PPP-Blinky up and running you can test your WebSocket service using this: http://jsfiddle.net/d26cyuh2/112/embedded/result
Websockets are ideal for building browser-based GUIs for mbed hardware.

/media/uploads/nixnax/ppp-blinky-websocke-2.gif

Trying PPP-Blinky on your mbed board

You will need an mbed-enabled hardware board: https://developer.mbed.org/platforms/

Establish a serial port connection between your host PC and your mbed board. The easiest way is to use mbed hardware with a USB serial debug port. I've tried the ST-Micro Nucleo-L476RG, Nucleo-L152RE, Nucleo-F401RE, Nucleo-L432KC, Nucleo-L053R8, mbed-LPC11U24 and mbed-LPC1768 boards and they all work out of the box. Use the mbed online compiler to compile the software for your target board. Save the compiled binary to your hardware.

Before establishing a network connection, you can verify the operation of the code by opening a terminal program such as Tera Term, and setting the baud rate of the COM port on your mbed board to 115200 baud. LED1 should toggle for every two 0x7E (~) (i.e. tilde) characters you type, as 0x7E is the PPP frame start/end marker. Don't forget to close the port when your'e done testing, or else Windows Dial-up Networking will report that the COM port is in use by another program when you try to connect.

Once you are certain that the serial port and firmware is working, proceed to creating a new network connection on your PC -see below.

Creating a Dial-up Connection in Windows

/media/uploads/nixnax/modem.jpg

Setting up Dial-Up Networking (DUN) on your Windows 7 or 8 PC is essentially a two-step process: First, you create a new modem device, because PPP-blinky partially emulates a standard Windows serial port modem device. Second, you create a new Internet connection (in practice, a new network adapter) which is associated with your new "modem".

Step-by-step description of how to configure Windows for PPP-Blinky here:

/users/nixnax/code/PPP-Blinky/wiki/Configuring-Windows-Dial-Up-Networking

There is also a screen on how to set up Linux dial-up networking near the bottom of this page.

Connecting to PPP-Blinky from your PC

Once Windows networking is configured you can establish a dial-up connection to your mbed board over the USB virtual com port.

The IP address you manually assigned to the new dial-up network adapter (172.10.10.1) functions as a gateway to any valid IP address on that subnet. In the screen capture below, I'm sending pings from the Windows 8 command line to my ST-Micro Nucleo-L476RG board over the USB virtual serial Port. I'm also using a second serial port and Tera Term to capture the debug output from a second serial port on the hardware. The optional debug output from the board prints out the IP source and destination address and the first few bytes of the data payload. Note that the source is the adapter IP address, (172.10.10.1 in this case) and the destination is some other address on that subnet - all packets to the subnet are sent to our mbed hardware. For example, you could also ping 172.10.10.123 or, if your PPP-Blinky is running, simply click on this link: http://172.10.10.123

/media/uploads/nixnax/ping-cap-3.gif

One Million Pings!

In the image below the ICMP ("ping") echo reply service was tested by sending one million pings to ppp-Blinky. This took over two hours.
The ping tool used on the Windows 8 PC was psping.exe from PsTools by Mark Russinovich - http://bit.ly/PingFast
The average reply time for a short ping (1 byte of payload data) was 11 milliseconds at 115200 baud on the $10 Nucleo-L053R8 board - barely enough time for 130 bytes to be sent over the port!

/media/uploads/nixnax/ppp-blinky-ping-results.jpg

Monitoring PPP-Blinky Packets

The image below is from a Microsoft Network Monitor 3.4 capture session.

Responses from PPP-Blinky are shown in blue.

Frame 2 - Internet Explorer at IP 172.10.10.1 (the Dial-Up Adapter IP) requests a TCP connection by sending an S (SYN) flag.
Frame 3 - PPP-Blinky at IP 172.10.10.2 responds with an ACK in frame 3. One direction of the link is now established.
Frame 4 - The PC acknowledges the SYN sent by PPP-Blinky in frame 3. The TCP link is now fully established.
Frame 5 - The browser "pushes" (P flag is set) an HTTP GET request to PPP-Blinky.
Frame 6 - PPP-Blinky responds with a standard HTTP response "pushes" (P flag set) back a small web page. It also sets the A (ACK) flag to acknowledge the message sent in frame 6.
Frame 7 - The PC acknowledges reception of the HTTP payload.
Frame 8 - The PC starts to shut down the TCP connection by sending a FIN flag.
Frame 9 - PPP-Blinky acknowledges the FIN request - the connection is now closed in one direction. It also sets a FIN flag in the response to request closure of the opposite direction of the connection.
Frame 10 - The PC acknowledges the FIN request. The closing of the TCP connection is now confirmed in both directions.

/media/uploads/nixnax/ms-network-monitor-http-get-1.gif

Debug Output

PPP-Blinky can output handy debug information to an optional second serial port.
The image below shows the debug output (Ident, Source, Destination, TCP Flags) for a complete HTTP conversation.
The PC messages are displayed in black. PPP-Blinky messages are blue.
Notice how PPP-blinky automatically inserts a blank line after each full HTTP conversation.

/media/uploads/nixnax/tcp-data-3.gif

Creating a Dial-Up Connection in Linux

The screen below shows the required pppd command to connect to PPP-Blinky from a Linux machine. This was much simpler than Windows! The USB serial port of the mbed LPC1768 board registered as /dev/ttyACM0 on my Linux box. Do a websearch on pppd if you want to learn more about pppd, the Linux PPP handler. Near the bottom of the screen below, two webpages are fetched (/ and /y) by using the curl command on the command line. Gnome Webkit and Firefox work fine, too. Also try echo GET / HTTP/1.1 | nc 172.10.10.2 which uses netcat, the "Swiss army knife" of networking tools. PPP-Blinky was also tested with ApacheBench, the Apache server benchmark software. After 100000 fetches, the mean page fetch rate was reported as 6 page fetches per second for a small page.

/media/uploads/nixnax/pppd-screen.png

Caveats

PPP Blinky is an extremely sparse implementation (1.5k lines) of HTTP,WebSocket,TCP, UDP, ICMP, IPCP and LCP over PPP, requiring around 8kB of RAM. The minimum functionality required to establish connectivity is implemented. These are often acceptable tradeoffs for embedded projects as well as a handy tool to learn the practical details of everyday networking implementations.

main.cpp@83:cdcb81d1910f, 2017-07-18 (annotated)

Committer:
nixnax
Date:
Tue Jul 18 00:17:03 2017 +0000
Revision:
83:cdcb81d1910f
Parent:
82:051f77f7dd72
Child:
84:456e73151f11
Increment TCP ident; Code consolidation;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 81:9ede60e9a2c8 1 // PPP-Blinky - "My Internet Of Thing"
nixnax 0:2cf4880c312a 2
nixnax 72:ad3d12753acf 3 // A Tiny Webserver Using Windows XP/7/8/10 Dial-Up Networking Over A Serial Port.
nixnax 0:2cf4880c312a 4
nixnax 41:e58a5a09f411 5 // Also receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 4:a469050d5b80 6
nixnax 81:9ede60e9a2c8 7 // Copyright 2016 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax 81:9ede60e9a2c8 8
nixnax 41:e58a5a09f411 9 // Notes and Instructions
nixnax 41:e58a5a09f411 10 // http://bit.ly/PPP-Blinky-Instructions
nixnax 0:2cf4880c312a 11
nixnax 41:e58a5a09f411 12 // Handy reading material
nixnax 6:fba4c2e817b8 13 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 14 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 39:b90183d35f1e 15 // http://bit.ly/dialup777error - how to solve Dial Up Error 777 in Windows 7/8/10
nixnax 41:e58a5a09f411 16 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 17
nixnax 29:30de79d658f6 18 // Handy tools
nixnax 44:d0c61ae49ea5 19 // https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax 44:d0c61ae49ea5 20 // Wireshark - can't monitor Dial-Up network packets on windows, but useful - can import our dumpFrame routine's hex output
nixnax 29:30de79d658f6 21 // Microsoft network monitor - real-time monitoring of all our packets
nixnax 29:30de79d658f6 22 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 29:30de79d658f6 23 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE)
nixnax 41:e58a5a09f411 24 // The curl.exe program in Windows Powershell - use it like this to stress test the webserver: while (1) { curl 172.10.10.1 }
nixnax 29:30de79d658f6 25 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 41:e58a5a09f411 26 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 41:e58a5a09f411 27
nixnax 81:9ede60e9a2c8 28 #include "mbed.h"
nixnax 66:f005b9fdf4d1 29
nixnax 66:f005b9fdf4d1 30 // The #define below enables/disables a SECOND (optional) serial port that prints out interesting diagnostic messages.
nixnax 66:f005b9fdf4d1 31 // Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor this.
nixnax 82:051f77f7dd72 32 #define SERIAL_PORT_MONITOR_NO /* or change to SERIAL_PORT_MONITOR_YES */
nixnax 0:2cf4880c312a 33
nixnax 41:e58a5a09f411 34 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 66:f005b9fdf4d1 35 Serial xx(PC_10, PC_11); // Not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax 42:4de44be70bfd 36 #define debug(x...) xx.printf (x)
nixnax 41:e58a5a09f411 37 #else
nixnax 42:4de44be70bfd 38 #define debug(x...) {}
nixnax 41:e58a5a09f411 39 #endif
nixnax 41:e58a5a09f411 40
nixnax 66:f005b9fdf4d1 41 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 83:cdcb81d1910f 42 #define v0 1
nixnax 66:f005b9fdf4d1 43 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 81:9ede60e9a2c8 44 #define v1 0
nixnax 77:abf92baebb42 45 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 77:abf92baebb42 46 #define v2 0
nixnax 29:30de79d658f6 47
nixnax 66:f005b9fdf4d1 48 // this is the webpage we serve when we get an HTTP request
nixnax 72:ad3d12753acf 49 // keep size under 900 bytes to fit into a single frame
nixnax 66:f005b9fdf4d1 50 const static char ourWebPage[] = "\
nixnax 66:f005b9fdf4d1 51 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 52 <html>\
nixnax 66:f005b9fdf4d1 53 <head>\
nixnax 66:f005b9fdf4d1 54 <title>mbed-PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 55 <script>\
nixnax 66:f005b9fdf4d1 56 window.onload=function(){\
nixnax 66:f005b9fdf4d1 57 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 66:f005b9fdf4d1 58 x().textContent = parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 59 </script>\
nixnax 66:f005b9fdf4d1 60 </head>\
nixnax 66:f005b9fdf4d1 61 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 62 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 63 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 64 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 65 </body>\
nixnax 69:23f560087c16 66 </html>"; // around 464 bytes long
nixnax 69:23f560087c16 67
nixnax 69:23f560087c16 68
nixnax 66:f005b9fdf4d1 69
nixnax 73:2f56ec87dbe9 70 // The serial port on your mbed hardware. Your PC should be configured to view this port as a standard dial-up networking modem.
nixnax 73:2f56ec87dbe9 71 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 72:ad3d12753acf 72 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 73 // See instructions at the top.
nixnax 73:2f56ec87dbe9 74 // On a typical mbed hardware platform this serial port is a USB virtual com port (VCP) and the USB serial driver is supplied by the board vendor.
nixnax 73:2f56ec87dbe9 75 Serial pc(USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax 29:30de79d658f6 76
nixnax 29:30de79d658f6 77 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 78
nixnax 66:f005b9fdf4d1 79 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 80 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 81
nixnax 29:30de79d658f6 82 // the serial port receive buffer and packet buffer
nixnax 0:2cf4880c312a 83
nixnax 29:30de79d658f6 84 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 85 struct pppType {
nixnax 38:ab582987926e 86 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 87 int ident; // our IP ident value
nixnax 38:ab582987926e 88 unsigned int seq; // our TCP sequence number
nixnax 38:ab582987926e 89 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 90 int ledState; // state of LED1
nixnax 4:a469050d5b80 91 struct {
nixnax 81:9ede60e9a2c8 92 #define RXBUFLEN (1<<14)
nixnax 81:9ede60e9a2c8 93 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in rxHandler
nixnax 72:ad3d12753acf 94 //char * buf;
nixnax 29:30de79d658f6 95 volatile int head;
nixnax 29:30de79d658f6 96 volatile int tail;
nixnax 81:9ede60e9a2c8 97 volatile int buflevel;
nixnax 38:ab582987926e 98 } rx; // serial port objects
nixnax 4:a469050d5b80 99 struct {
nixnax 38:ab582987926e 100 int len; // number of bytes in buffer
nixnax 38:ab582987926e 101 int crc; // PPP CRC (frame check)
nixnax 72:ad3d12753acf 102 //char * buf; // the actual buffer
nixnax 77:abf92baebb42 103 #define TCP_max_size 3300
nixnax 77:abf92baebb42 104 char buf[TCP_max_size]; // send and receive buffer large enough for unstuffed (decoded) hdlc frames
nixnax 38:ab582987926e 105 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 106 struct {
nixnax 50:ad4e7c3c88e5 107 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 108 int frameEndIndex; // frame end marker
nixnax 81:9ede60e9a2c8 109 int frameFound; // we have found at least one start of frame already
nixnax 50:ad4e7c3c88e5 110 } hdlc; // hdlc frame objects
nixnax 29:30de79d658f6 111 };
nixnax 31:e000c1b9c565 112
nixnax 29:30de79d658f6 113 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 114
nixnax 60:2b770949c911 115 // Initialize our globals
nixnax 29:30de79d658f6 116 void pppInitStruct()
nixnax 29:30de79d658f6 117 {
nixnax 81:9ede60e9a2c8 118 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 29:30de79d658f6 119 ppp.online=0;
nixnax 81:9ede60e9a2c8 120 __disable_irq();
nixnax 29:30de79d658f6 121 ppp.rx.tail=0;
nixnax 29:30de79d658f6 122 ppp.rx.head=0;
nixnax 81:9ede60e9a2c8 123 __enable_irq();
nixnax 81:9ede60e9a2c8 124 ppp.rx.buflevel=0;
nixnax 29:30de79d658f6 125 ppp.pkt.len=0;
nixnax 83:cdcb81d1910f 126 ppp.ident=1000;
nixnax 29:30de79d658f6 127 ppp.ledState=0;
nixnax 81:9ede60e9a2c8 128 ppp.hdlc.frameFound=0;
nixnax 81:9ede60e9a2c8 129 ppp.hdlc.frameStartIndex=0;
nixnax 29:30de79d658f6 130 }
nixnax 26:11f4eb2663a7 131
nixnax 43:aa57db08995d 132 void led1Toggle()
nixnax 43:aa57db08995d 133 {
nixnax 43:aa57db08995d 134 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 135 led1 = ppp.ledState;
nixnax 43:aa57db08995d 136 }
nixnax 43:aa57db08995d 137
nixnax 29:30de79d658f6 138 void crcReset()
nixnax 29:30de79d658f6 139 {
nixnax 29:30de79d658f6 140 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 141 }
nixnax 4:a469050d5b80 142
nixnax 29:30de79d658f6 143 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 144 {
nixnax 29:30de79d658f6 145 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 146 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 147 x>>=1;
nixnax 29:30de79d658f6 148 }
nixnax 29:30de79d658f6 149 }
nixnax 29:30de79d658f6 150
nixnax 29:30de79d658f6 151 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 152 {
nixnax 31:e000c1b9c565 153 crcReset();
nixnax 31:e000c1b9c565 154 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 155 return ppp.crc;
nixnax 29:30de79d658f6 156 }
nixnax 0:2cf4880c312a 157
nixnax 0:2cf4880c312a 158 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 159 {
nixnax 17:4918c893d802 160 while ( pc.readable() ) {
nixnax 81:9ede60e9a2c8 161 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap
nixnax 83:cdcb81d1910f 162 if ( hd == ppp.rx.tail ) {
nixnax 83:cdcb81d1910f 163 debug("Receive buffer is full. ppp.rx.buflevel = %d\n",ppp.rx.buflevel);
nixnax 83:cdcb81d1910f 164 break; // watch for buffer full
nixnax 83:cdcb81d1910f 165 }
nixnax 17:4918c893d802 166 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 167 ppp.rx.head = hd; // update head pointer
nixnax 81:9ede60e9a2c8 168 ppp.rx.buflevel++;
nixnax 15:b0154c910143 169 }
nixnax 0:2cf4880c312a 170 }
nixnax 0:2cf4880c312a 171
nixnax 22:00df34cd4d7e 172 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 173 {
nixnax 22:00df34cd4d7e 174 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 175 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 176 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 177 return emptyStatus;
nixnax 0:2cf4880c312a 178 }
nixnax 0:2cf4880c312a 179
nixnax 0:2cf4880c312a 180 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 181 {
nixnax 63:9253b0e1b7d8 182 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 81:9ede60e9a2c8 183 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 81:9ede60e9a2c8 184 ppp.rx.buflevel--;
nixnax 63:9253b0e1b7d8 185 return x;
nixnax 0:2cf4880c312a 186 }
nixnax 0:2cf4880c312a 187
nixnax 50:ad4e7c3c88e5 188 void processHDLCFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 189 {
nixnax 38:ab582987926e 190 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 191 if(start==end) {
nixnax 29:30de79d658f6 192 return;
nixnax 29:30de79d658f6 193 }
nixnax 9:0992486d4a30 194 crcReset();
nixnax 9:0992486d4a30 195 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 196 ppp.pkt.len=0;
nixnax 9:0992486d4a30 197 int unstuff=0;
nixnax 17:4918c893d802 198 int idx = start;
nixnax 17:4918c893d802 199 while(1) {
nixnax 9:0992486d4a30 200 if (unstuff==0) {
nixnax 72:ad3d12753acf 201 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 202 else {
nixnax 72:ad3d12753acf 203 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 204 ppp.pkt.len++;
nixnax 29:30de79d658f6 205 dest++;
nixnax 72:ad3d12753acf 206 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 207 }
nixnax 66:f005b9fdf4d1 208 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 209 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 210 ppp.pkt.len++;
nixnax 29:30de79d658f6 211 dest++;
nixnax 72:ad3d12753acf 212 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 213 unstuff=0;
nixnax 9:0992486d4a30 214 }
nixnax 81:9ede60e9a2c8 215 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 216 if (idx == end) break;
nixnax 9:0992486d4a30 217 }
nixnax 29:30de79d658f6 218 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 219 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 220 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 221 determinePacketType();
nixnax 29:30de79d658f6 222 } else if (v0) {
nixnax 66:f005b9fdf4d1 223 debug("PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // ignore packets with CRC errors but print a debug line
nixnax 9:0992486d4a30 224 }
nixnax 9:0992486d4a30 225 }
nixnax 9:0992486d4a30 226
nixnax 38:ab582987926e 227 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 228 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 229 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 230 void dumpFrame()
nixnax 29:30de79d658f6 231 {
nixnax 42:4de44be70bfd 232 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 233 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 234 }
nixnax 16:cb0b80c24ba2 235
nixnax 29:30de79d658f6 236 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 237 {
nixnax 29:30de79d658f6 238 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 239 pc.putc(0x7d);
nixnax 66:f005b9fdf4d1 240 pc.putc(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 241 } else {
nixnax 29:30de79d658f6 242 pc.putc(ch);
nixnax 29:30de79d658f6 243 }
nixnax 11:f58998c24f0b 244 }
nixnax 9:0992486d4a30 245
nixnax 66:f005b9fdf4d1 246 void sendFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 247 {
nixnax 17:4918c893d802 248 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 249 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 250 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 251 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 252 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 253 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 254 }
nixnax 9:0992486d4a30 255
nixnax 66:f005b9fdf4d1 256 void ipConfigRequestHandler()
nixnax 29:30de79d658f6 257 {
nixnax 64:677b9713a120 258 debug("IPCP Conf ");
nixnax 9:0992486d4a30 259 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 66:f005b9fdf4d1 260 debug("Rej\n"); // reject any options that are requested
nixnax 9:0992486d4a30 261 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 262 sendFrame();
nixnax 9:0992486d4a30 263 } else {
nixnax 64:677b9713a120 264 debug("Ack\n");
nixnax 9:0992486d4a30 265 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 266 sendFrame(); // acknowledge
nixnax 64:677b9713a120 267 debug("IPCP Ask\n");
nixnax 9:0992486d4a30 268 // send our own request now
nixnax 12:db0dc91f0231 269 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 270 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 271 sendFrame(); // this is our request
nixnax 9:0992486d4a30 272 }
nixnax 9:0992486d4a30 273 }
nixnax 9:0992486d4a30 274
nixnax 29:30de79d658f6 275 void ipAckHandler()
nixnax 29:30de79d658f6 276 {
nixnax 64:677b9713a120 277 debug("IPCP Grant\n");
nixnax 29:30de79d658f6 278 }
nixnax 9:0992486d4a30 279
nixnax 29:30de79d658f6 280 void ipNackHandler()
nixnax 29:30de79d658f6 281 {
nixnax 64:677b9713a120 282 debug("IPCP Nack\n");
nixnax 29:30de79d658f6 283 }
nixnax 9:0992486d4a30 284
nixnax 29:30de79d658f6 285 void ipDefaultHandler()
nixnax 29:30de79d658f6 286 {
nixnax 64:677b9713a120 287 debug("IPCP Other\n");
nixnax 29:30de79d658f6 288 }
nixnax 29:30de79d658f6 289
nixnax 29:30de79d658f6 290 void IPCPframe()
nixnax 29:30de79d658f6 291 {
nixnax 9:0992486d4a30 292 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 293 switch (code) {
nixnax 29:30de79d658f6 294 case 1:
nixnax 66:f005b9fdf4d1 295 ipConfigRequestHandler();
nixnax 29:30de79d658f6 296 break;
nixnax 29:30de79d658f6 297 case 2:
nixnax 29:30de79d658f6 298 ipAckHandler();
nixnax 29:30de79d658f6 299 break;
nixnax 29:30de79d658f6 300 case 3:
nixnax 29:30de79d658f6 301 ipNackHandler();
nixnax 29:30de79d658f6 302 break;
nixnax 29:30de79d658f6 303 default:
nixnax 29:30de79d658f6 304 ipDefaultHandler();
nixnax 9:0992486d4a30 305 }
nixnax 29:30de79d658f6 306 }
nixnax 9:0992486d4a30 307
nixnax 29:30de79d658f6 308 void UDPpacket()
nixnax 29:30de79d658f6 309 {
nixnax 12:db0dc91f0231 310 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 311 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 312 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 63:9253b0e1b7d8 313 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 314 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 315 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 316 #endif
nixnax 12:db0dc91f0231 317 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 318 char * udpInf = udpBlock+8; // actual start of info
nixnax 63:9253b0e1b7d8 319 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 320 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 321 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 322 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 323 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 324 #endif
nixnax 29:30de79d658f6 325 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 326 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 81:9ede60e9a2c8 327 if(v0) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 81:9ede60e9a2c8 328 if(v0) debug("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 83:cdcb81d1910f 329 if(v0) debug("Len %03d", udpLength);
nixnax 29:30de79d658f6 330 int printSize = udpLength;
nixnax 29:30de79d658f6 331 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 332 if (v1) {
nixnax 29:30de79d658f6 333 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 334 char ch = udpInf[i];
nixnax 29:30de79d658f6 335 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 336 debug("%c", ch);
nixnax 29:30de79d658f6 337 } else {
nixnax 64:677b9713a120 338 debug("_");
nixnax 29:30de79d658f6 339 }
nixnax 29:30de79d658f6 340 }
nixnax 29:30de79d658f6 341 }
nixnax 83:cdcb81d1910f 342 if (v0) debug("\n");
nixnax 12:db0dc91f0231 343 }
nixnax 11:f58998c24f0b 344
nixnax 76:00e208cceb8b 345 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 346 {
nixnax 77:abf92baebb42 347
nixnax 75:0d513869231f 348 unsigned int sum=0;
nixnax 76:00e208cceb8b 349 unsigned char placeHolder;
nixnax 29:30de79d658f6 350 if (len&1) {
nixnax 76:00e208cceb8b 351 placeHolder = ptr[len]; // when length is odd stuff in a zero byte
nixnax 76:00e208cceb8b 352 ptr[len]=0;
nixnax 29:30de79d658f6 353 }
nixnax 29:30de79d658f6 354 for (int i=0; i<len/2; i++) {
nixnax 76:00e208cceb8b 355 unsigned int hi = *ptr;
nixnax 29:30de79d658f6 356 ptr++;
nixnax 76:00e208cceb8b 357 unsigned int lo = *ptr;
nixnax 29:30de79d658f6 358 ptr++;
nixnax 76:00e208cceb8b 359 unsigned int val = ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 360 sum = sum + val;
nixnax 11:f58998c24f0b 361 }
nixnax 29:30de79d658f6 362 if (len&1) {
nixnax 76:00e208cceb8b 363 ptr[len] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 364 }
nixnax 76:00e208cceb8b 365 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 366 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 367 return ~sum;
nixnax 29:30de79d658f6 368 }
nixnax 11:f58998c24f0b 369
nixnax 29:30de79d658f6 370 void headerCheckSum()
nixnax 29:30de79d658f6 371 {
nixnax 11:f58998c24f0b 372 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 373 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 374 int sum=0;
nixnax 11:f58998c24f0b 375
nixnax 29:30de79d658f6 376 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 377 int hi = *ptr;
nixnax 29:30de79d658f6 378 ptr++;
nixnax 29:30de79d658f6 379 int lo = *ptr;
nixnax 29:30de79d658f6 380 ptr++;
nixnax 11:f58998c24f0b 381 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 382 sum = sum + val;
nixnax 11:f58998c24f0b 383 }
nixnax 11:f58998c24f0b 384 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 385 sum = ~sum;
nixnax 11:f58998c24f0b 386 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 387 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 388 }
nixnax 9:0992486d4a30 389
nixnax 29:30de79d658f6 390 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 391 {
nixnax 12:db0dc91f0231 392 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 393 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 394 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 395 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 396 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 397 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 398 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 399 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 400 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 401 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 402 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 403 char * dstAdr = ipPkt+16;
nixnax 63:9253b0e1b7d8 404 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 405 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 406 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 63:9253b0e1b7d8 407 #endif
nixnax 81:9ede60e9a2c8 408 if(v0) debug("ICMP PING %d.%d.%d.%d %d.%d.%d.%d ", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3],dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 81:9ede60e9a2c8 409 if(v0) debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 410 char src[4];
nixnax 29:30de79d658f6 411 char dst[4];
nixnax 12:db0dc91f0231 412 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 413 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 414 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 415 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 416 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 417 chkSum[0]=0;
nixnax 29:30de79d658f6 418 chkSum[1]=0;
nixnax 12:db0dc91f0231 419 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 420 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 421 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 422 icmpSum[0]=0;
nixnax 29:30de79d658f6 423 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 424 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 425 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 426 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 427 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 428
nixnax 16:cb0b80c24ba2 429 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 430 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 431 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 432 if (v0) {
nixnax 29:30de79d658f6 433 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 434 char ch = icmpData[i];
nixnax 29:30de79d658f6 435 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 436 debug("%c",ch);
nixnax 29:30de79d658f6 437 } else {
nixnax 64:677b9713a120 438 debug("_");
nixnax 29:30de79d658f6 439 }
nixnax 29:30de79d658f6 440 }
nixnax 64:677b9713a120 441 debug("\n");
nixnax 29:30de79d658f6 442 }
nixnax 15:b0154c910143 443 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 444
nixnax 12:db0dc91f0231 445 } else {
nixnax 29:30de79d658f6 446 if (v0) {
nixnax 42:4de44be70bfd 447 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 448 }
nixnax 11:f58998c24f0b 449 }
nixnax 11:f58998c24f0b 450 }
nixnax 11:f58998c24f0b 451
nixnax 29:30de79d658f6 452 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 453 {
nixnax 29:30de79d658f6 454 if (v0) {
nixnax 42:4de44be70bfd 455 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 456 }
nixnax 29:30de79d658f6 457 }
nixnax 11:f58998c24f0b 458
nixnax 29:30de79d658f6 459 void dumpHeaderIP ()
nixnax 29:30de79d658f6 460 {
nixnax 26:11f4eb2663a7 461 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 462 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 463 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 464 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 465 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 466 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 467 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 468 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 469 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 470 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 471 char * protocol = ipPkt+9; // 1 byte
nixnax 77:abf92baebb42 472 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 473 #endif
nixnax 26:11f4eb2663a7 474 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 475 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 476
nixnax 55:43faae812be3 477 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 478 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 479 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 480 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 481 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 482 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 483 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 484 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 485 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 486 int protocolIP = protocol[0];
nixnax 76:00e208cceb8b 487 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 488 #endif
nixnax 55:43faae812be3 489
nixnax 29:30de79d658f6 490 char srcIP [16];
nixnax 29:30de79d658f6 491 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 492 char dstIP [16];
nixnax 29:30de79d658f6 493 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 82:051f77f7dd72 494 if (v0) debug("IP %s %s v%d h%d d%d e%d L%03d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 42:4de44be70bfd 495 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 496 }
nixnax 26:11f4eb2663a7 497
nixnax 29:30de79d658f6 498 void dumpHeaderTCP()
nixnax 29:30de79d658f6 499 {
nixnax 83:cdcb81d1910f 500 if( v0 ) {
nixnax 81:9ede60e9a2c8 501
nixnax 81:9ede60e9a2c8 502 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 81:9ede60e9a2c8 503 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 63:9253b0e1b7d8 504 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 81:9ede60e9a2c8 505 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 81:9ede60e9a2c8 506 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 63:9253b0e1b7d8 507 #endif
nixnax 81:9ede60e9a2c8 508 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 63:9253b0e1b7d8 509 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 81:9ede60e9a2c8 510 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 81:9ede60e9a2c8 511 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 63:9253b0e1b7d8 512 #endif
nixnax 81:9ede60e9a2c8 513 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 514
nixnax 81:9ede60e9a2c8 515 char flagInfo[10]; // text string presentating the TCP flags
nixnax 81:9ede60e9a2c8 516 memset(flagInfo,'.', 9); // fill string with "........."
nixnax 81:9ede60e9a2c8 517 memset(flagInfo+9,0,1); // null terminate string
nixnax 66:f005b9fdf4d1 518
nixnax 81:9ede60e9a2c8 519 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 81:9ede60e9a2c8 520 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 81:9ede60e9a2c8 521 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 81:9ede60e9a2c8 522 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 81:9ede60e9a2c8 523 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 81:9ede60e9a2c8 524 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 81:9ede60e9a2c8 525 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 81:9ede60e9a2c8 526 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 81:9ede60e9a2c8 527 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 81:9ede60e9a2c8 528 debug("TCP Flags %s Seq %u Ack %u\n", flagInfo, seq, ack); // show the flags in debug
nixnax 29:30de79d658f6 529 }
nixnax 29:30de79d658f6 530 }
nixnax 29:30de79d658f6 531
nixnax 68:0b74763ae67f 532 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 533 {
nixnax 67:a63e3486bcda 534 int n=0; // number of bytes we have printed so far
nixnax 77:abf92baebb42 535 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 536 int contentLengthStart; // index where HTML starts
nixnax 77:abf92baebb42 537
nixnax 67:a63e3486bcda 538 if(strncmp(dataStart, "GET / HTTP/1.1", 14) == 0 ) {
nixnax 67:a63e3486bcda 539 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 83:cdcb81d1910f 540 } else {
nixnax 67:a63e3486bcda 541 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 83:cdcb81d1910f 542 }
nixnax 83:cdcb81d1910f 543
nixnax 83:cdcb81d1910f 544 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 545 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 546 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 547 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 548 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header must end with empty line (\r\n)
nixnax 83:cdcb81d1910f 549 nHeader=n; // size of HTTP header
nixnax 67:a63e3486bcda 550
nixnax 83:cdcb81d1910f 551 if(strncmp(dataStart, "GET / HTTP/1.1", 14) == 0 ) {
nixnax 83:cdcb81d1910f 552 // this is where we insert our web page into the buffer
nixnax 83:cdcb81d1910f 553 n=n+sprintf(n+dataStart,"%s", ourWebPage);
nixnax 83:cdcb81d1910f 554 } else {
nixnax 83:cdcb81d1910f 555 // all other requests get 404 Not Found response a
nixnax 67:a63e3486bcda 556 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head></head>"); // html start
nixnax 83:cdcb81d1910f 557 n=n+sprintf(n+dataStart,"<body>Not Found %06d</body>",ppp.ident); // here we print a variable in the html
nixnax 83:cdcb81d1910f 558 n=n+sprintf(n+dataStart,"</html>"); // html end
nixnax 83:cdcb81d1910f 559 }
nixnax 83:cdcb81d1910f 560
nixnax 83:cdcb81d1910f 561 while( (n%4)!= 2)
nixnax 83:cdcb81d1910f 562 n=n+sprintf(n+dataStart," "); // insert spaces until n is exactly two away from a multiple of four
nixnax 83:cdcb81d1910f 563 n=n+sprintf(n+dataStart,"\r\n"); // add the last \r\n sequence - n is now an exact multiple of four
nixnax 83:cdcb81d1910f 564 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 565 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 566 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 567 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 568
nixnax 77:abf92baebb42 569 if (v2) {
nixnax 77:abf92baebb42 570 debug("HTTP Response: HTTP-header %d HTTP-content %d HTTP-total %d\n",nHeader,n-nHeader,n);
nixnax 77:abf92baebb42 571 }
nixnax 67:a63e3486bcda 572 return n; // total byte size of our response
nixnax 67:a63e3486bcda 573 }
nixnax 67:a63e3486bcda 574
nixnax 67:a63e3486bcda 575
nixnax 29:30de79d658f6 576 void tcpHandler()
nixnax 29:30de79d658f6 577 {
nixnax 26:11f4eb2663a7 578 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 579 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 580 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 581 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 582 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 583 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 584 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 585 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 586 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 587 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 588
nixnax 29:30de79d658f6 589 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 590 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 591 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 592 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 593 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 594 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 595 char * flagbitstcp = s + 12; // 9 bits
nixnax 82:051f77f7dd72 596 char * windowsizetcp = s + 14; // 2 bytes
nixnax 26:11f4eb2663a7 597 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 598
nixnax 26:11f4eb2663a7 599 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 600 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 601 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 602
nixnax 35:e7068df4d971 603 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 604
nixnax 35:e7068df4d971 605 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 606 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 81:9ede60e9a2c8 607
nixnax 77:abf92baebb42 608 unsigned int ack = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]) + tcpDataSize;
nixnax 79:f0fc1c19a550 609 unsigned int seq = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]); // use their idea of our seq
nixnax 81:9ede60e9a2c8 610
nixnax 28:1aa629be05e7 611
nixnax 29:30de79d658f6 612 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 613 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 614 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 615 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 616 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 617
nixnax 35:e7068df4d971 618 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 619 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 620 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 621
nixnax 69:23f560087c16 622 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 69:23f560087c16 623 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 69:23f560087c16 624 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 77:abf92baebb42 625
nixnax 69:23f560087c16 626 switch ( flagsTCP ) {
nixnax 69:23f560087c16 627 case TCP_FLAG_ACK:
nixnax 69:23f560087c16 628 if ( tcpDataSize != 1 ) return;
nixnax 79:f0fc1c19a550 629 ack++;
nixnax 69:23f560087c16 630 case TCP_FLAG_SYN:
nixnax 82:051f77f7dd72 631 // ignore all TCP options by shortening packet to 40 bytes
nixnax 82:051f77f7dd72 632 pktLen[1] = 40; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 633 packetLength = 40; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 634 headerSizeTCP = 20; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 635 tcpSize = 20; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 636 headerSizeTCP = 20; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 637 offset[0] = (headerSizeTCP/4)<<4; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 638
nixnax 69:23f560087c16 639 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - ack it
nixnax 81:9ede60e9a2c8 640 ppp.seq = ppp.seq + 10000; // create a new sequence number (normally random)
nixnax 79:f0fc1c19a550 641 seq = ppp.seq; // create a new sequence number (normally random)
nixnax 79:f0fc1c19a550 642 ack++; // for SYN flag we have to increase their sequence by 1
nixnax 69:23f560087c16 643 break;
nixnax 77:abf92baebb42 644 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 69:23f560087c16 645 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 69:23f560087c16 646 fastResponse = 1; // we can respond fast to a push
nixnax 69:23f560087c16 647 if ( strncmp(dataStart, "GET ", 4) == 0) { // do we see an http GET command
nixnax 69:23f560087c16 648 dataLen = httpResponse(dataStart); // send an http response
nixnax 69:23f560087c16 649 while((dataLen %4 ) !=0) { // dataLen must be a multiple of four
nixnax 77:abf92baebb42 650 dataLen++; // must be a multiple of four
nixnax 77:abf92baebb42 651 dataStart[dataLen-1]=0; // clear the byte in the buffer
nixnax 80:753f5dd2e84e 652 ack++;
nixnax 69:23f560087c16 653 }
nixnax 69:23f560087c16 654 }
nixnax 69:23f560087c16 655 break;
nixnax 77:abf92baebb42 656 case TCP_FLAG_FIN:
nixnax 69:23f560087c16 657 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 69:23f560087c16 658 case TCP_FLAG_FIN | TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 77:abf92baebb42 659 ack++; // for FIN flag we have to increase sequence by 1
nixnax 69:23f560087c16 660 break;
nixnax 77:abf92baebb42 661 default:
nixnax 69:23f560087c16 662 return; // ignore remaining packets
nixnax 28:1aa629be05e7 663 }
nixnax 81:9ede60e9a2c8 664
nixnax 77:abf92baebb42 665
nixnax 69:23f560087c16 666 // The TCP flag handling is now done
nixnax 38:ab582987926e 667 // Now we have to recalculate all the header sizes, swap IP address/port source and destination, and do the IP and TCP checksums
nixnax 26:11f4eb2663a7 668
nixnax 83:cdcb81d1910f 669 ppp.ident++; //
nixnax 83:cdcb81d1910f 670 ident[0] = ppp.ident>>8;
nixnax 83:cdcb81d1910f 671 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 83:cdcb81d1910f 672
nixnax 65:23b17c43aa0f 673 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 674 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 675 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 676 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 677
nixnax 60:2b770949c911 678 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 679 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 680 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 83:cdcb81d1910f 681
nixnax 82:051f77f7dd72 682 windowsizetcp[0]=16; // ignore window size negotiation
nixnax 82:051f77f7dd72 683 windowsizetcp[1]=0; // ignore winodw size negotiation
nixnax 29:30de79d658f6 684
nixnax 38:ab582987926e 685 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 686 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 687 acktcp[2]=ack>>8;
nixnax 67:a63e3486bcda 688 acktcp[3]=ack>>0; // save ack 32-bit integer
nixnax 38:ab582987926e 689
nixnax 38:ab582987926e 690 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 691 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 692 seqtcp[2]=seq>>8;
nixnax 67:a63e3486bcda 693 seqtcp[3]=seq>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 694
nixnax 38:ab582987926e 695 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 696
nixnax 38:ab582987926e 697 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 698 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 699 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 700 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 701 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 702
nixnax 38:ab582987926e 703 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 704
nixnax 61:b3c1a04efd0a 705 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 706 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 707 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 708
nixnax 64:677b9713a120 709 // now we have to build the so-called 12-byte TCP "pseudo-header" in front of the TCP header (containing some IP header values) in order to correctly calculate the TCP checksum
nixnax 63:9253b0e1b7d8 710 // this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax 63:9253b0e1b7d8 711
nixnax 62:f192926e42f1 712 char * pseudoHeader = s-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 713 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 714 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 715 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 716 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 717 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 718 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 719
nixnax 61:b3c1a04efd0a 720 // pseudo-header built, now we can calculate TCP checksum
nixnax 63:9253b0e1b7d8 721
nixnax 29:30de79d658f6 722 checksumtcp[0]=0;
nixnax 29:30de79d658f6 723 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 724 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 725 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 726 checksumtcp[1]=pseudoHeaderSum;
nixnax 61:b3c1a04efd0a 727 memcpy( s-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 60:2b770949c911 728
nixnax 36:2a9b457f8276 729 if (fastResponse==1) {
nixnax 36:2a9b457f8276 730 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 731 } else {
nixnax 81:9ede60e9a2c8 732 // normally, you wait 200 ms before responding to a TCP packet
nixnax 68:0b74763ae67f 733 // remove the wait to respond faster
nixnax 78:809c2631a5eb 734 // wait(0.2);
nixnax 36:2a9b457f8276 735 }
nixnax 83:cdcb81d1910f 736 sendFrame(); // All preparation complete - send the TCP response
nixnax 83:cdcb81d1910f 737 dumpHeaderIP();
nixnax 81:9ede60e9a2c8 738 dumpHeaderTCP();
nixnax 29:30de79d658f6 739 }
nixnax 26:11f4eb2663a7 740
nixnax 29:30de79d658f6 741 void dumpDataTCP()
nixnax 29:30de79d658f6 742 {
nixnax 26:11f4eb2663a7 743 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 744 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 745 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 746 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 747 if (v1) {
nixnax 42:4de44be70bfd 748 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 749 }
nixnax 29:30de79d658f6 750 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 751 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 42:4de44be70bfd 752 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 753 }
nixnax 29:30de79d658f6 754 }
nixnax 26:11f4eb2663a7 755
nixnax 29:30de79d658f6 756 void TCPpacket()
nixnax 29:30de79d658f6 757 {
nixnax 83:cdcb81d1910f 758 dumpHeaderIP();
nixnax 81:9ede60e9a2c8 759 dumpHeaderTCP();
nixnax 77:abf92baebb42 760 if (v2) {
nixnax 77:abf92baebb42 761 dumpDataTCP();
nixnax 77:abf92baebb42 762 }
nixnax 26:11f4eb2663a7 763 tcpHandler();
nixnax 11:f58998c24f0b 764 }
nixnax 11:f58998c24f0b 765
nixnax 29:30de79d658f6 766 void otherProtocol()
nixnax 29:30de79d658f6 767 {
nixnax 64:677b9713a120 768 debug("Other IP protocol");
nixnax 29:30de79d658f6 769 }
nixnax 26:11f4eb2663a7 770
nixnax 29:30de79d658f6 771 void IPframe()
nixnax 29:30de79d658f6 772 {
nixnax 10:74f8233f72c0 773 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 774 switch (protocol) {
nixnax 29:30de79d658f6 775 case 1:
nixnax 29:30de79d658f6 776 ICMPpacket();
nixnax 29:30de79d658f6 777 break;
nixnax 29:30de79d658f6 778 case 2:
nixnax 29:30de79d658f6 779 IGMPpacket();
nixnax 29:30de79d658f6 780 break;
nixnax 29:30de79d658f6 781 case 17:
nixnax 29:30de79d658f6 782 UDPpacket();
nixnax 29:30de79d658f6 783 break;
nixnax 29:30de79d658f6 784 case 6:
nixnax 29:30de79d658f6 785 TCPpacket();
nixnax 29:30de79d658f6 786 break;
nixnax 29:30de79d658f6 787 default:
nixnax 29:30de79d658f6 788 otherProtocol();
nixnax 29:30de79d658f6 789 }
nixnax 29:30de79d658f6 790 }
nixnax 9:0992486d4a30 791
nixnax 29:30de79d658f6 792 void LCPconfReq()
nixnax 29:30de79d658f6 793 {
nixnax 64:677b9713a120 794 debug("LCP Config ");
nixnax 9:0992486d4a30 795 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 796 ppp.pkt.buf[4]=4; // allow only no options
nixnax 64:677b9713a120 797 debug("Reject\n");
nixnax 29:30de79d658f6 798 sendFrame();
nixnax 9:0992486d4a30 799 } else {
nixnax 9:0992486d4a30 800 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 64:677b9713a120 801 debug("Ack\n");
nixnax 9:0992486d4a30 802 sendFrame();
nixnax 64:677b9713a120 803 debug("LCP Ask\n");
nixnax 11:f58998c24f0b 804 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 805 sendFrame();
nixnax 9:0992486d4a30 806 }
nixnax 9:0992486d4a30 807 }
nixnax 9:0992486d4a30 808
nixnax 29:30de79d658f6 809 void LCPconfAck()
nixnax 29:30de79d658f6 810 {
nixnax 64:677b9713a120 811 debug("LCP Ack\n");
nixnax 29:30de79d658f6 812 }
nixnax 9:0992486d4a30 813
nixnax 29:30de79d658f6 814 void LCPend()
nixnax 29:30de79d658f6 815 {
nixnax 29:30de79d658f6 816 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 817 sendFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 818 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 819 pppInitStruct(); // flush the receive buffer
nixnax 81:9ede60e9a2c8 820 debug("LCP End\n");
nixnax 9:0992486d4a30 821 }
nixnax 9:0992486d4a30 822
nixnax 29:30de79d658f6 823 void LCPother()
nixnax 29:30de79d658f6 824 {
nixnax 64:677b9713a120 825 debug("LCP Other\n");
nixnax 29:30de79d658f6 826 dumpFrame();
nixnax 29:30de79d658f6 827 }
nixnax 29:30de79d658f6 828
nixnax 29:30de79d658f6 829 void LCPframe()
nixnax 29:30de79d658f6 830 {
nixnax 29:30de79d658f6 831 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 832 switch (code) {
nixnax 29:30de79d658f6 833 case 1:
nixnax 29:30de79d658f6 834 LCPconfReq();
nixnax 29:30de79d658f6 835 break; // config request
nixnax 29:30de79d658f6 836 case 2:
nixnax 29:30de79d658f6 837 LCPconfAck();
nixnax 29:30de79d658f6 838 break; // config ack
nixnax 29:30de79d658f6 839 case 5:
nixnax 29:30de79d658f6 840 LCPend();
nixnax 29:30de79d658f6 841 break; // end connection
nixnax 29:30de79d658f6 842 default:
nixnax 29:30de79d658f6 843 LCPother();
nixnax 29:30de79d658f6 844 }
nixnax 9:0992486d4a30 845 }
nixnax 9:0992486d4a30 846
nixnax 29:30de79d658f6 847 void discardedFrame()
nixnax 29:30de79d658f6 848 {
nixnax 29:30de79d658f6 849 if (v0) {
nixnax 71:965619fedb3a 850 debug("Frame is not IP, IPCP or LCP: %02x %02x %02x %02x\n", ppp.pkt.buf[0],ppp.pkt.buf[1],ppp.pkt.buf[2],ppp.pkt.buf[3]);
nixnax 29:30de79d658f6 851 }
nixnax 9:0992486d4a30 852 }
nixnax 9:0992486d4a30 853
nixnax 29:30de79d658f6 854 void determinePacketType()
nixnax 29:30de79d658f6 855 {
nixnax 29:30de79d658f6 856 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 64:677b9713a120 857 debug("byte0 != ff\n");
nixnax 29:30de79d658f6 858 return;
nixnax 29:30de79d658f6 859 }
nixnax 29:30de79d658f6 860 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 64:677b9713a120 861 debug("byte1 != 3\n");
nixnax 29:30de79d658f6 862 return;
nixnax 29:30de79d658f6 863 }
nixnax 29:30de79d658f6 864 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 64:677b9713a120 865 debug("byte2 != 21\n");
nixnax 29:30de79d658f6 866 return;
nixnax 29:30de79d658f6 867 }
nixnax 9:0992486d4a30 868 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 869 switch (packetType) {
nixnax 29:30de79d658f6 870 case 0xc0:
nixnax 29:30de79d658f6 871 LCPframe();
nixnax 29:30de79d658f6 872 break; // link control
nixnax 29:30de79d658f6 873 case 0x80:
nixnax 29:30de79d658f6 874 IPCPframe();
nixnax 29:30de79d658f6 875 break; // IP control
nixnax 29:30de79d658f6 876 case 0x00:
nixnax 29:30de79d658f6 877 IPframe();
nixnax 29:30de79d658f6 878 break; // IP itself
nixnax 29:30de79d658f6 879 default:
nixnax 29:30de79d658f6 880 discardedFrame();
nixnax 9:0992486d4a30 881 }
nixnax 29:30de79d658f6 882 }
nixnax 9:0992486d4a30 883
nixnax 50:ad4e7c3c88e5 884 void wait_for_HDLC_frame()
nixnax 50:ad4e7c3c88e5 885 {
nixnax 81:9ede60e9a2c8 886 while(1)
nixnax 81:9ede60e9a2c8 887 if ( rxbufNotEmpty() ) {
nixnax 81:9ede60e9a2c8 888 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 889 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 890 if (rx==FRAME_7E) {
nixnax 81:9ede60e9a2c8 891 if (ppp.hdlc.frameFound == 0) { // we are still waiting for a frame start
nixnax 81:9ede60e9a2c8 892 ppp.hdlc.frameFound = 1; // we found our first frame start
nixnax 81:9ede60e9a2c8 893 ppp.hdlc.frameStartIndex=ppp.rx.tail; // remember where the frame character is in the buffer
nixnax 51:a86d56844324 894 } else {
nixnax 81:9ede60e9a2c8 895 // we have previously found a frame start
nixnax 81:9ede60e9a2c8 896 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 81:9ede60e9a2c8 897 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 81:9ede60e9a2c8 898 ppp.hdlc.frameStartIndex = ppp.rx.tail; // where next frame will start
nixnax 81:9ede60e9a2c8 899 break;
nixnax 50:ad4e7c3c88e5 900 }
nixnax 50:ad4e7c3c88e5 901 }
nixnax 50:ad4e7c3c88e5 902 }
nixnax 50:ad4e7c3c88e5 903 }
nixnax 50:ad4e7c3c88e5 904
nixnax 29:30de79d658f6 905 void scanForConnectString()
nixnax 29:30de79d658f6 906 {
nixnax 81:9ede60e9a2c8 907 while(ppp.online == 0) {
nixnax 81:9ede60e9a2c8 908 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 81:9ede60e9a2c8 909 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENTCLIENT" );
nixnax 81:9ede60e9a2c8 910 // also search for HDLC frame start character 0x7e
nixnax 81:9ede60e9a2c8 911 void * found2 = memchr( (char *)ppp.rx.buf, 0x7e, RXBUFLEN );
nixnax 81:9ede60e9a2c8 912 if( (found1 != NULL) | (found2 != NULL) ) {
nixnax 81:9ede60e9a2c8 913 if (found1 != NULL) {
nixnax 82:051f77f7dd72 914 memset(ppp.rx.buf, 0x20, RXBUFLEN); // clear the receive buffer
nixnax 81:9ede60e9a2c8 915 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 81:9ede60e9a2c8 916 pc.puts("CLIENTSERVER");
nixnax 81:9ede60e9a2c8 917 if (v0) debug("Found connect string \"CLIENTCLIENT\"\n");
nixnax 81:9ede60e9a2c8 918 }
nixnax 81:9ede60e9a2c8 919 if (found2 != NULL) {
nixnax 81:9ede60e9a2c8 920 if (v0) debug("Found HDLC frame start (7E)\n");
nixnax 81:9ede60e9a2c8 921 }
nixnax 71:965619fedb3a 922 ppp.online=1; // we are connected, so stop looking for the string
nixnax 9:0992486d4a30 923 }
nixnax 9:0992486d4a30 924 }
nixnax 81:9ede60e9a2c8 925
nixnax 9:0992486d4a30 926 }
nixnax 9:0992486d4a30 927
nixnax 0:2cf4880c312a 928 int main()
nixnax 0:2cf4880c312a 929 {
nixnax 14:c65831c25aaa 930 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 931 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 49:2213f9c132b2 932 xx.baud(115200); // second serial port for debug messages
nixnax 9:0992486d4a30 933 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 934 #endif
nixnax 9:0992486d4a30 935 pppInitStruct(); // initialize all the PPP properties
nixnax 81:9ede60e9a2c8 936 ppp.seq=1000; // initial TCP sequence number
nixnax 81:9ede60e9a2c8 937
nixnax 9:0992486d4a30 938 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 0:2cf4880c312a 939 while(1) {
nixnax 51:a86d56844324 940 scanForConnectString(); // respond to connect command from windows dial up networking
nixnax 81:9ede60e9a2c8 941 while(ppp.online) {
nixnax 81:9ede60e9a2c8 942 wait_for_HDLC_frame();
nixnax 81:9ede60e9a2c8 943 }
nixnax 7:ab147f5e97ac 944 }
nixnax 7:ab147f5e97ac 945 }