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.

PPP-Blinky/ppp-blinky.cpp@142:54d1543e23e5, 2017-08-28 (annotated)

Committer:
nixnax
Date:
Mon Aug 28 18:47:48 2017 +0000
Revision:
142:54d1543e23e5
Child:
143:c5019f856a56
Documentation, restructure, comments.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 142:54d1543e23e5 1 // PPP-Blinky - "The Most Basic Internet Of a Thing"
nixnax 142:54d1543e23e5 2 // A Tiny HTTP Webserver Using Windows XP/7/8/10/Linux Dial-Up Networking Over A Serial Port.
nixnax 142:54d1543e23e5 3 // Receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 142:54d1543e23e5 4 // WebSocket Service - see https://en.wikipedia.org/wiki/WebSocket
nixnax 142:54d1543e23e5 5
nixnax 142:54d1543e23e5 6 // Copyright 2016/2017 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 142:54d1543e23e5 7
nixnax 142:54d1543e23e5 8 // Notes and Instructions
nixnax 142:54d1543e23e5 9 // http://bit.ly/PPP-Blinky-Instructions
nixnax 142:54d1543e23e5 10 // http://bit.ly/win-rasdial-config
nixnax 142:54d1543e23e5 11
nixnax 142:54d1543e23e5 12 // Handy reading material
nixnax 142:54d1543e23e5 13 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 142:54d1543e23e5 14 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 142:54d1543e23e5 15 // http://atari.kensclassics.org/wcomlog.htm
nixnax 142:54d1543e23e5 16
nixnax 142:54d1543e23e5 17 // Handy tools
nixnax 142:54d1543e23e5 18 // 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 142:54d1543e23e5 19 // https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax 142:54d1543e23e5 20 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 142:54d1543e23e5 21 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE), then custom relected-in=1, reflected-out=1
nixnax 142:54d1543e23e5 22 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 142:54d1543e23e5 23 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 142:54d1543e23e5 24 // Windows Powershell invoke-webrequest command - use it to stress test the webserver like this: while (1){ invoke-webrequest -uri 172.10.10.1/x }
nixnax 142:54d1543e23e5 25
nixnax 142:54d1543e23e5 26 // Connecting PPP-Blinky to Linux
nixnax 142:54d1543e23e5 27 // PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax 142:54d1543e23e5 28 // pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax 142:54d1543e23e5 29 // in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax 142:54d1543e23e5 30 // See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax 142:54d1543e23e5 31
nixnax 142:54d1543e23e5 32 // Special pages when PPP-Blinky is running
nixnax 142:54d1543e23e5 33 // 172.10.10.2 root page
nixnax 142:54d1543e23e5 34 // 172.10.10.2/x returns a number that increments every time you request a page - this is handy for testing
nixnax 142:54d1543e23e5 35 // 172.10.10.2/xb also returns a number, but issues a fast refresh command. This allows you to use your browser to benchmark page load speed
nixnax 142:54d1543e23e5 36 // 172.10.10.2/ws a simple WebSocket demo
nixnax 142:54d1543e23e5 37 // http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle
nixnax 142:54d1543e23e5 38
nixnax 142:54d1543e23e5 39 // Ok, enough talking, time to check out some code!!
nixnax 142:54d1543e23e5 40
nixnax 142:54d1543e23e5 41 #include "ppp-blinky.h"
nixnax 142:54d1543e23e5 42
nixnax 142:54d1543e23e5 43 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax 142:54d1543e23e5 44 // 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 142:54d1543e23e5 45 // Using the second serial port will slow down packet response time
nixnax 142:54d1543e23e5 46 // Note - the LPC11U24 does NOT have a second serial port
nixnax 142:54d1543e23e5 47 #define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax 142:54d1543e23e5 48
nixnax 142:54d1543e23e5 49 // here we define the OPTIONAL, second debug serial port for various mbed target boards
nixnax 142:54d1543e23e5 50 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 51 #if defined(TARGET_LPC1768)
nixnax 142:54d1543e23e5 52 Serial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax 142:54d1543e23e5 53 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
nixnax 142:54d1543e23e5 54 Serial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax 142:54d1543e23e5 55 #elif defined(TARGET_LPC11U24)
nixnax 142:54d1543e23e5 56 #error The LPC11U24 does not have a second serial port to use for debugging - change SERIAL_PORT_MONITOR_YES back to SERIAL_PORT_MONITOR_NO
nixnax 142:54d1543e23e5 57 #elif defined (TARGET_KL46Z) || (TARGET_KL25Z)
nixnax 142:54d1543e23e5 58 Serial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax 142:54d1543e23e5 59 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 142:54d1543e23e5 60 // change the next line to YOUR target board's second serial port pin definition if it's not present - and if it works, please send it to me - thanks!!!
nixnax 142:54d1543e23e5 61 Serial xx(p9, p10); // change this to YOUR board second serial port pin definition - and please send it to me if it works!!!
nixnax 142:54d1543e23e5 62 #else
nixnax 142:54d1543e23e5 63 #error Add your target board's second serial port here if you want to use debugging - or simply change SERIAL_PORT_MONITOR_YES to SERIAL_PORT_MONITOR_NO
nixnax 142:54d1543e23e5 64 #endif
nixnax 142:54d1543e23e5 65 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we print debug messages */
nixnax 142:54d1543e23e5 66 #define debugPutc(x...) xx.putc(x)
nixnax 142:54d1543e23e5 67 #define debugBaudRate(x...) xx.baud(x)
nixnax 142:54d1543e23e5 68 #else
nixnax 142:54d1543e23e5 69 // if we don't have a debug port the debug print functions do nothing
nixnax 142:54d1543e23e5 70 #define debugPrintf(x...) {}
nixnax 142:54d1543e23e5 71 #define debugPutc(x...) {}
nixnax 142:54d1543e23e5 72 #define debugBaudRate(x...) {}
nixnax 142:54d1543e23e5 73 #endif
nixnax 142:54d1543e23e5 74
nixnax 142:54d1543e23e5 75 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 142:54d1543e23e5 76 #define v0 1
nixnax 142:54d1543e23e5 77 #define v1 0
nixnax 142:54d1543e23e5 78 #define v2 0
nixnax 142:54d1543e23e5 79 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 142:54d1543e23e5 80 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 142:54d1543e23e5 81
nixnax 142:54d1543e23e5 82 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 142:54d1543e23e5 83 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 142:54d1543e23e5 84
nixnax 142:54d1543e23e5 85 const static char rootWebPage[] = "\
nixnax 142:54d1543e23e5 86 <!DOCTYPE html>\
nixnax 142:54d1543e23e5 87 <html>\
nixnax 142:54d1543e23e5 88 <head>\
nixnax 142:54d1543e23e5 89 <title>mbed PPP-Blinky</title>\
nixnax 142:54d1543e23e5 90 <script>\
nixnax 142:54d1543e23e5 91 window.onload=function(){\
nixnax 142:54d1543e23e5 92 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 142:54d1543e23e5 93 x().textContent=parseInt(x().textContent)+1;},100);};\
nixnax 142:54d1543e23e5 94 </script>\
nixnax 142:54d1543e23e5 95 </head>\
nixnax 142:54d1543e23e5 96 <body style=\"font-family: sans-serif; font-size:20px; text-align:center; color:#807070\">\
nixnax 142:54d1543e23e5 97 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 142:54d1543e23e5 98 <h1 id=\"w\">0</h1>\
nixnax 142:54d1543e23e5 99 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 142:54d1543e23e5 100 <h1><a href=\"/ws\">WebSocket Demo</a></h1>\
nixnax 142:54d1543e23e5 101 <h1><a href=\"/x\">Benchmark 1</a></h1>\
nixnax 142:54d1543e23e5 102 <h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax 142:54d1543e23e5 103 <h1><a href=\"http://jsfiddle.net/d26cyuh2/\">JSFiddle Demo</a></h1>\
nixnax 142:54d1543e23e5 104 </body>\
nixnax 142:54d1543e23e5 105 </html>"; // size = 634 bytes plus 1 null byte = 635 bytes
nixnax 142:54d1543e23e5 106
nixnax 142:54d1543e23e5 107 const static char webSocketPage[] = "\
nixnax 142:54d1543e23e5 108 <!DOCTYPE html>\
nixnax 142:54d1543e23e5 109 <html>\
nixnax 142:54d1543e23e5 110 <head>\
nixnax 142:54d1543e23e5 111 <title>mbed PPP-Blinky</title>\
nixnax 142:54d1543e23e5 112 <script>\
nixnax 142:54d1543e23e5 113 window.onload=function(){\
nixnax 142:54d1543e23e5 114 var url=\"ws://172.10.10.2\";\
nixnax 142:54d1543e23e5 115 var sts=document.getElementById(\"sts\");\
nixnax 142:54d1543e23e5 116 var btn=document.getElementById(\"btn\");\
nixnax 142:54d1543e23e5 117 var ctr=0;\
nixnax 142:54d1543e23e5 118 function show(text){sts.textContent=text;}\
nixnax 142:54d1543e23e5 119 btn.onclick=function(){\
nixnax 142:54d1543e23e5 120 if(btn.textContent==\"Connect\"){\
nixnax 142:54d1543e23e5 121 x=new WebSocket(url);\
nixnax 142:54d1543e23e5 122 x.onopen=function(){\
nixnax 142:54d1543e23e5 123 show(\"Connected to : \"+url);\
nixnax 142:54d1543e23e5 124 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 142:54d1543e23e5 125 };\
nixnax 142:54d1543e23e5 126 x.onclose=function(){show(\"closed\");};\
nixnax 142:54d1543e23e5 127 x.onmessage=function(msg){show(\"PPP-Blinky Sent: \\\"\"+msg.data+\"\\\"\");};\
nixnax 142:54d1543e23e5 128 } else {\
nixnax 142:54d1543e23e5 129 x.send(ctr);\
nixnax 142:54d1543e23e5 130 ctr=ctr+1;\
nixnax 142:54d1543e23e5 131 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 142:54d1543e23e5 132 }\
nixnax 142:54d1543e23e5 133 };\
nixnax 142:54d1543e23e5 134 };\
nixnax 142:54d1543e23e5 135 </script>\
nixnax 142:54d1543e23e5 136 <body style=\"font-family: sans-serif; font-size:25px; color:#807070\">\
nixnax 142:54d1543e23e5 137 <h1>PPP-Blinky WebSocket Test</h1>\
nixnax 142:54d1543e23e5 138 <div id=\"sts\">Idle</div>\
nixnax 142:54d1543e23e5 139 <button id=\"btn\" style=\"font-size: 100%; margin-top: 55px; margin-bottom: 55px;\">Connect</button>\
nixnax 142:54d1543e23e5 140 <h4><a href=\"/\">PPP-Blinky home</a></h4>\
nixnax 142:54d1543e23e5 141 </body>\
nixnax 142:54d1543e23e5 142 </html>"; // size = 916 bytes + 1 null byte = 917 bytes
nixnax 142:54d1543e23e5 143
nixnax 142:54d1543e23e5 144 // The serial port on your mbed hardware. Your PC should be configured to view this port as a standard dial-up networking modem.
nixnax 142:54d1543e23e5 145 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 142:54d1543e23e5 146 // The modem baud rate should be set to 115200 baud
nixnax 142:54d1543e23e5 147 // See instructions at the top.
nixnax 142:54d1543e23e5 148 // 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 142:54d1543e23e5 149 BufferedSerial pc(USBTX, USBRX, 100); // usb virtual com port for mbed hardware
nixnax 142:54d1543e23e5 150
nixnax 142:54d1543e23e5 151 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 142:54d1543e23e5 152
nixnax 142:54d1543e23e5 153 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 142:54d1543e23e5 154 #define FRAME_7E (0x7e)
nixnax 142:54d1543e23e5 155
nixnax 142:54d1543e23e5 156 /// a structure to keep all our ppp globals in
nixnax 142:54d1543e23e5 157 struct pppType {
nixnax 142:54d1543e23e5 158 int online; // we hunt for a PPP connection if this is zero
nixnax 142:54d1543e23e5 159 int crc; // for calculating IP and TCP CRCs
nixnax 142:54d1543e23e5 160 int ledState; // state of LED1
nixnax 142:54d1543e23e5 161 int httpPageCount;
nixnax 142:54d1543e23e5 162 int firstFrame; // cleared after first frame
nixnax 142:54d1543e23e5 163 struct {
nixnax 142:54d1543e23e5 164 #define RXBUFLEN (1<<11)
nixnax 142:54d1543e23e5 165 // the serial port receive buffer and packet buffer, size is RXBUFLEN (currently 2048 bytes)
nixnax 142:54d1543e23e5 166 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in ring buffer
nixnax 142:54d1543e23e5 167 int head;
nixnax 142:54d1543e23e5 168 int tail;
nixnax 142:54d1543e23e5 169 int rtail;
nixnax 142:54d1543e23e5 170 int buflevel;
nixnax 142:54d1543e23e5 171 } rx; // serial port objects
nixnax 142:54d1543e23e5 172 struct {
nixnax 142:54d1543e23e5 173 int len; // number of bytes in buffer
nixnax 142:54d1543e23e5 174 int crc; // PPP CRC (frame check)
nixnax 142:54d1543e23e5 175 #define PPP_max_size 2500
nixnax 142:54d1543e23e5 176 // we are assuming 1000 bytes more than MTU size of 1500 - due to the PPP encoding of special bytes
nixnax 142:54d1543e23e5 177 char buf[PPP_max_size]; // send and receive buffer large enough for raw, encoded PPP/HDLC frames
nixnax 142:54d1543e23e5 178 } pkt; // ppp buffer objects
nixnax 142:54d1543e23e5 179 struct {
nixnax 142:54d1543e23e5 180 int frameStartIndex; // frame start marker
nixnax 142:54d1543e23e5 181 int frameEndIndex; // frame end marker
nixnax 142:54d1543e23e5 182 } hdlc; // hdlc frame objects
nixnax 142:54d1543e23e5 183 struct {
nixnax 142:54d1543e23e5 184 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 142:54d1543e23e5 185 } ip; // ip related object
nixnax 142:54d1543e23e5 186 };
nixnax 142:54d1543e23e5 187
nixnax 142:54d1543e23e5 188 pppType ppp; // our global - definitely not thread safe
nixnax 142:54d1543e23e5 189
nixnax 142:54d1543e23e5 190 /// Initialize the ppp structure and clear the receive buffer
nixnax 142:54d1543e23e5 191 void pppInitStruct()
nixnax 142:54d1543e23e5 192 {
nixnax 142:54d1543e23e5 193 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 142:54d1543e23e5 194 ppp.online=0;
nixnax 142:54d1543e23e5 195 ppp.rx.tail=0;
nixnax 142:54d1543e23e5 196 ppp.rx.rtail=0;
nixnax 142:54d1543e23e5 197 ppp.rx.head=0;
nixnax 142:54d1543e23e5 198 ppp.rx.buflevel=0;
nixnax 142:54d1543e23e5 199 ppp.pkt.len=0;
nixnax 142:54d1543e23e5 200 ppp.ip.ident=10000; // easy to recognize in ip packet dumps
nixnax 142:54d1543e23e5 201 ppp.ledState=0;
nixnax 142:54d1543e23e5 202 ppp.hdlc.frameStartIndex=0;
nixnax 142:54d1543e23e5 203 ppp.httpPageCount=0;
nixnax 142:54d1543e23e5 204 ppp.firstFrame=1;
nixnax 142:54d1543e23e5 205 }
nixnax 142:54d1543e23e5 206
nixnax 142:54d1543e23e5 207 /// Toggle the LED on every second PPP packet received
nixnax 142:54d1543e23e5 208 void led1Toggle()
nixnax 142:54d1543e23e5 209 {
nixnax 142:54d1543e23e5 210 led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax 142:54d1543e23e5 211 ppp.ledState++;
nixnax 142:54d1543e23e5 212
nixnax 142:54d1543e23e5 213 }
nixnax 142:54d1543e23e5 214
nixnax 142:54d1543e23e5 215 /// returns 1 after a connect messasge, 0 at startup or after a disconnect message
nixnax 142:54d1543e23e5 216 int connected()
nixnax 142:54d1543e23e5 217 {
nixnax 142:54d1543e23e5 218 return ppp.online;
nixnax 142:54d1543e23e5 219 }
nixnax 142:54d1543e23e5 220
nixnax 142:54d1543e23e5 221 /// check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf
nixnax 142:54d1543e23e5 222 void checkPc()
nixnax 142:54d1543e23e5 223 {
nixnax 142:54d1543e23e5 224 char ch;
nixnax 142:54d1543e23e5 225 if ( pc.readable() ) {
nixnax 142:54d1543e23e5 226 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 142:54d1543e23e5 227 if ( hd == ppp.rx.rtail ) {
nixnax 142:54d1543e23e5 228 debugPrintf("\nReceive buffer full\n");
nixnax 142:54d1543e23e5 229 return;
nixnax 142:54d1543e23e5 230 }
nixnax 142:54d1543e23e5 231 ch = pc.getc(); // read new character
nixnax 142:54d1543e23e5 232 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 142:54d1543e23e5 233 if ( ppp.online == 0 ) {
nixnax 142:54d1543e23e5 234 if (ch == 0x7E) {
nixnax 142:54d1543e23e5 235 ppp.online = 1;
nixnax 142:54d1543e23e5 236 }
nixnax 142:54d1543e23e5 237 }
nixnax 142:54d1543e23e5 238 ppp.rx.head = hd; // update head pointer
nixnax 142:54d1543e23e5 239 ppp.rx.buflevel++;
nixnax 142:54d1543e23e5 240 }
nixnax 142:54d1543e23e5 241 }
nixnax 142:54d1543e23e5 242
nixnax 142:54d1543e23e5 243 /// print to debug port while checking for incoming characters
nixnax 142:54d1543e23e5 244 void putcWhileCheckingInput( char outByte )
nixnax 142:54d1543e23e5 245 {
nixnax 142:54d1543e23e5 246 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 247 checkPc();
nixnax 142:54d1543e23e5 248 debugPutc( outByte );
nixnax 142:54d1543e23e5 249 checkPc();
nixnax 142:54d1543e23e5 250 #endif
nixnax 142:54d1543e23e5 251 }
nixnax 142:54d1543e23e5 252
nixnax 142:54d1543e23e5 253 /// puts to debug port while checking the PPP input stream
nixnax 142:54d1543e23e5 254 void putsWhileCheckingInput( char * data )
nixnax 142:54d1543e23e5 255 {
nixnax 142:54d1543e23e5 256 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 257 char * nextChar = data;
nixnax 142:54d1543e23e5 258 while( *nextChar != 0 ) {
nixnax 142:54d1543e23e5 259 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 142:54d1543e23e5 260 nextChar++;
nixnax 142:54d1543e23e5 261 }
nixnax 142:54d1543e23e5 262 #endif
nixnax 142:54d1543e23e5 263 }
nixnax 142:54d1543e23e5 264
nixnax 142:54d1543e23e5 265 /// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 142:54d1543e23e5 266 void qq()
nixnax 142:54d1543e23e5 267 {
nixnax 142:54d1543e23e5 268 if ( pc.readable() ) putsWhileCheckingInput( "Character available!\n" );
nixnax 142:54d1543e23e5 269 }
nixnax 142:54d1543e23e5 270
nixnax 142:54d1543e23e5 271 /// Initialize the PPP CRC total
nixnax 142:54d1543e23e5 272 void crcReset()
nixnax 142:54d1543e23e5 273 {
nixnax 142:54d1543e23e5 274 ppp.crc=0xffff; // crc restart
nixnax 142:54d1543e23e5 275 }
nixnax 142:54d1543e23e5 276
nixnax 142:54d1543e23e5 277 /// update the cumulative PPP CRC
nixnax 142:54d1543e23e5 278 void crcDo(int x)
nixnax 142:54d1543e23e5 279 {
nixnax 142:54d1543e23e5 280 for (int i=0; i<8; i++) {
nixnax 142:54d1543e23e5 281 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 142:54d1543e23e5 282 x>>=1;
nixnax 142:54d1543e23e5 283 }
nixnax 142:54d1543e23e5 284 checkPc(); // handle input
nixnax 142:54d1543e23e5 285 }
nixnax 142:54d1543e23e5 286
nixnax 142:54d1543e23e5 287 /// calculate the PPP CRC on an entire block of memory
nixnax 142:54d1543e23e5 288 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 142:54d1543e23e5 289 {
nixnax 142:54d1543e23e5 290 crcReset();
nixnax 142:54d1543e23e5 291 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 142:54d1543e23e5 292 return ppp.crc;
nixnax 142:54d1543e23e5 293 }
nixnax 142:54d1543e23e5 294
nixnax 142:54d1543e23e5 295 /// Get one character from our received PPP buffer
nixnax 142:54d1543e23e5 296 int pc_getBuf()
nixnax 142:54d1543e23e5 297 {
nixnax 142:54d1543e23e5 298 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 142:54d1543e23e5 299 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 142:54d1543e23e5 300 ppp.rx.buflevel--;
nixnax 142:54d1543e23e5 301 return x;
nixnax 142:54d1543e23e5 302 }
nixnax 142:54d1543e23e5 303
nixnax 142:54d1543e23e5 304 /// Dump a PPP frame to the debug serial port
nixnax 142:54d1543e23e5 305 /// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 142:54d1543e23e5 306 /// Capture the frame's hex output in your terminal program and save as a text file
nixnax 142:54d1543e23e5 307 /// In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 142:54d1543e23e5 308 void dumpPPPFrame()
nixnax 142:54d1543e23e5 309 {
nixnax 142:54d1543e23e5 310 char pbuf[30];
nixnax 142:54d1543e23e5 311 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 312 checkPc();
nixnax 142:54d1543e23e5 313 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 142:54d1543e23e5 314 checkPc();
nixnax 142:54d1543e23e5 315 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 316 }
nixnax 142:54d1543e23e5 317 checkPc();
nixnax 142:54d1543e23e5 318 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 142:54d1543e23e5 319 checkPc();
nixnax 142:54d1543e23e5 320 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 321 }
nixnax 142:54d1543e23e5 322
nixnax 142:54d1543e23e5 323 /// Process a received PPP frame
nixnax 142:54d1543e23e5 324 void processPPPFrame(int start, int end)
nixnax 142:54d1543e23e5 325 {
nixnax 142:54d1543e23e5 326 led1Toggle(); // change led1 state on every frame we receive
nixnax 142:54d1543e23e5 327 if(start==end) {
nixnax 142:54d1543e23e5 328 return; // empty frame
nixnax 142:54d1543e23e5 329 }
nixnax 142:54d1543e23e5 330 crcReset();
nixnax 142:54d1543e23e5 331 char * dest = ppp.pkt.buf;
nixnax 142:54d1543e23e5 332 ppp.pkt.len=0;
nixnax 142:54d1543e23e5 333 int unstuff=0;
nixnax 142:54d1543e23e5 334 int idx = start;
nixnax 142:54d1543e23e5 335 while(1) {
nixnax 142:54d1543e23e5 336 checkPc();
nixnax 142:54d1543e23e5 337 if (unstuff==0) {
nixnax 142:54d1543e23e5 338 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 142:54d1543e23e5 339 else {
nixnax 142:54d1543e23e5 340 *dest = ppp.rx.buf[idx];
nixnax 142:54d1543e23e5 341 ppp.pkt.len++;
nixnax 142:54d1543e23e5 342 dest++;
nixnax 142:54d1543e23e5 343 crcDo(ppp.rx.buf[idx]);
nixnax 142:54d1543e23e5 344 }
nixnax 142:54d1543e23e5 345 } else { // unstuff characters prefixed with 0x7d
nixnax 142:54d1543e23e5 346 *dest = ppp.rx.buf[idx]^0x20;
nixnax 142:54d1543e23e5 347 ppp.pkt.len++;
nixnax 142:54d1543e23e5 348 dest++;
nixnax 142:54d1543e23e5 349 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 142:54d1543e23e5 350 unstuff=0;
nixnax 142:54d1543e23e5 351 }
nixnax 142:54d1543e23e5 352 idx = (idx+1) & (RXBUFLEN-1);
nixnax 142:54d1543e23e5 353 if (idx == end) break;
nixnax 142:54d1543e23e5 354 }
nixnax 142:54d1543e23e5 355 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 142:54d1543e23e5 356 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 142:54d1543e23e5 357 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 142:54d1543e23e5 358 determinePacketType();
nixnax 142:54d1543e23e5 359 } else {
nixnax 142:54d1543e23e5 360 #define REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 361 #ifdef REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 362 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 363 checkPc();
nixnax 142:54d1543e23e5 364 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 142:54d1543e23e5 365 checkPc();
nixnax 142:54d1543e23e5 366 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 367 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 142:54d1543e23e5 368 #endif
nixnax 142:54d1543e23e5 369 }
nixnax 142:54d1543e23e5 370 }
nixnax 142:54d1543e23e5 371
nixnax 142:54d1543e23e5 372 /// output a character to the PPP port while checking for incoming characters
nixnax 142:54d1543e23e5 373 void pcPutcWhileCheckingInput(int ch)
nixnax 142:54d1543e23e5 374 {
nixnax 142:54d1543e23e5 375 checkPc(); // check input
nixnax 142:54d1543e23e5 376 pc.putc(ch);
nixnax 142:54d1543e23e5 377 checkPc();
nixnax 142:54d1543e23e5 378 }
nixnax 142:54d1543e23e5 379
nixnax 142:54d1543e23e5 380 /// do PPP HDLC-like handling of special (flag) characters
nixnax 142:54d1543e23e5 381 void hdlcPut(int ch)
nixnax 142:54d1543e23e5 382 {
nixnax 142:54d1543e23e5 383 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 142:54d1543e23e5 384 pcPutcWhileCheckingInput(0x7d);
nixnax 142:54d1543e23e5 385 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 142:54d1543e23e5 386 } else {
nixnax 142:54d1543e23e5 387 pcPutcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 388 }
nixnax 142:54d1543e23e5 389 }
nixnax 142:54d1543e23e5 390
nixnax 142:54d1543e23e5 391 /// send a PPP frame in HDLC format
nixnax 142:54d1543e23e5 392 void send_pppFrame()
nixnax 142:54d1543e23e5 393 {
nixnax 142:54d1543e23e5 394 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 142:54d1543e23e5 395 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 142:54d1543e23e5 396 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 142:54d1543e23e5 397 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 142:54d1543e23e5 398 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 399 wait_us(86); // wait one character time
nixnax 142:54d1543e23e5 400 checkPc();
nixnax 142:54d1543e23e5 401 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 142:54d1543e23e5 402 }
nixnax 142:54d1543e23e5 403 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 142:54d1543e23e5 404 }
nixnax 142:54d1543e23e5 405
nixnax 142:54d1543e23e5 406 /// handle IPCP configuration requests
nixnax 142:54d1543e23e5 407 void ipcpConfigRequestHandler()
nixnax 142:54d1543e23e5 408 {
nixnax 142:54d1543e23e5 409 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 142:54d1543e23e5 410 ppp.pkt.buf[4]=2; // change code to ack
nixnax 142:54d1543e23e5 411 send_pppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 142:54d1543e23e5 412
nixnax 142:54d1543e23e5 413 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 142:54d1543e23e5 414 ppp.pkt.buf[4]=1; // change code to request
nixnax 142:54d1543e23e5 415 ppp.pkt.buf[7]=4; // no options in this request
nixnax 142:54d1543e23e5 416 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 142:54d1543e23e5 417 send_pppFrame(); // send our request
nixnax 142:54d1543e23e5 418 }
nixnax 142:54d1543e23e5 419
nixnax 142:54d1543e23e5 420 /// handle IPCP acknowledge (do nothing)
nixnax 142:54d1543e23e5 421 void ipcpAckHandler()
nixnax 142:54d1543e23e5 422 {
nixnax 142:54d1543e23e5 423 debugPrintf("Their IPCP Grant\n");
nixnax 142:54d1543e23e5 424 }
nixnax 142:54d1543e23e5 425
nixnax 142:54d1543e23e5 426 /// handle IPCP NACK by sending our suggested IP address if there is an IP involved
nixnax 142:54d1543e23e5 427 void ipcpNackHandler()
nixnax 142:54d1543e23e5 428 {
nixnax 142:54d1543e23e5 429 debugPrintf("Their IPCP Nack, Our ACK\n");
nixnax 142:54d1543e23e5 430 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 142:54d1543e23e5 431 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 142:54d1543e23e5 432 send_pppFrame(); // let's request this IP address as ours
nixnax 142:54d1543e23e5 433 } // if it's not an IP nack we ignore it
nixnax 142:54d1543e23e5 434 }
nixnax 142:54d1543e23e5 435
nixnax 142:54d1543e23e5 436 /// handle all other IPCP requests (by ignoring them)
nixnax 142:54d1543e23e5 437 void ipcpDefaultHandler()
nixnax 142:54d1543e23e5 438 {
nixnax 142:54d1543e23e5 439 debugPrintf("Their IPCP Other\n");
nixnax 142:54d1543e23e5 440 }
nixnax 142:54d1543e23e5 441
nixnax 142:54d1543e23e5 442 /// process an incoming IPCP packet
nixnax 142:54d1543e23e5 443 void IPCPframe()
nixnax 142:54d1543e23e5 444 {
nixnax 142:54d1543e23e5 445 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 142:54d1543e23e5 446 switch (code) {
nixnax 142:54d1543e23e5 447 case 1:
nixnax 142:54d1543e23e5 448 ipcpConfigRequestHandler();
nixnax 142:54d1543e23e5 449 break;
nixnax 142:54d1543e23e5 450 case 2:
nixnax 142:54d1543e23e5 451 ipcpAckHandler();
nixnax 142:54d1543e23e5 452 break;
nixnax 142:54d1543e23e5 453 case 3:
nixnax 142:54d1543e23e5 454 ipcpNackHandler();
nixnax 142:54d1543e23e5 455 break;
nixnax 142:54d1543e23e5 456 default:
nixnax 142:54d1543e23e5 457 ipcpDefaultHandler();
nixnax 142:54d1543e23e5 458 }
nixnax 142:54d1543e23e5 459 }
nixnax 142:54d1543e23e5 460
nixnax 142:54d1543e23e5 461 /// process an incoming UDP packet
nixnax 142:54d1543e23e5 462 void UDPpacket()
nixnax 142:54d1543e23e5 463 {
nixnax 142:54d1543e23e5 464 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 142:54d1543e23e5 465 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 142:54d1543e23e5 466 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 142:54d1543e23e5 467 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 468 char * udpSrc = udpBlock; // source port
nixnax 142:54d1543e23e5 469 char * udpDst = udpBlock+2; // destination port
nixnax 142:54d1543e23e5 470 #endif
nixnax 142:54d1543e23e5 471 char * udpLen = udpBlock+4; // udp data length
nixnax 142:54d1543e23e5 472 char * udpInf = udpBlock+8; // actual start of info
nixnax 142:54d1543e23e5 473 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 474 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 142:54d1543e23e5 475 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 142:54d1543e23e5 476 char * srcIP = udpPkt+12; // udp src addr
nixnax 142:54d1543e23e5 477 char * dstIP = udpPkt+16; // udp dst addr
nixnax 142:54d1543e23e5 478 #endif
nixnax 142:54d1543e23e5 479 #define UDP_HEADER_SIZE 8
nixnax 142:54d1543e23e5 480 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 142:54d1543e23e5 481 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 142:54d1543e23e5 482 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 142:54d1543e23e5 483 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 142:54d1543e23e5 484 int printSize = udpLength;
nixnax 142:54d1543e23e5 485 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 142:54d1543e23e5 486 if (v1) {
nixnax 142:54d1543e23e5 487 for (int i=0; i<printSize; i++) {
nixnax 142:54d1543e23e5 488 char ch = udpInf[i];
nixnax 142:54d1543e23e5 489 if (ch>31 && ch<127) {
nixnax 142:54d1543e23e5 490 debugPrintf("%c", ch);
nixnax 142:54d1543e23e5 491 } else {
nixnax 142:54d1543e23e5 492 debugPrintf("_");
nixnax 142:54d1543e23e5 493 }
nixnax 142:54d1543e23e5 494 }
nixnax 142:54d1543e23e5 495 }
nixnax 142:54d1543e23e5 496 if (v0) debugPrintf("\n");
nixnax 142:54d1543e23e5 497 }
nixnax 142:54d1543e23e5 498
nixnax 142:54d1543e23e5 499 /// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax 142:54d1543e23e5 500 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 142:54d1543e23e5 501 {
nixnax 142:54d1543e23e5 502 unsigned int i,hi,lo,sum;
nixnax 142:54d1543e23e5 503 unsigned char placeHolder;
nixnax 142:54d1543e23e5 504 if (len&1) {
nixnax 142:54d1543e23e5 505 placeHolder = ptr[len];
nixnax 142:54d1543e23e5 506 ptr[len]=0; // if the byte count is odd, insert one extra zero byte is after the last real byte because we sum byte PAIRS
nixnax 142:54d1543e23e5 507 }
nixnax 142:54d1543e23e5 508 sum=0;
nixnax 142:54d1543e23e5 509 i=0;
nixnax 142:54d1543e23e5 510 while ( i<len ) {
nixnax 142:54d1543e23e5 511 checkPc();
nixnax 142:54d1543e23e5 512 hi = ptr[i++];
nixnax 142:54d1543e23e5 513 lo = ptr[i++];
nixnax 142:54d1543e23e5 514 sum = sum + ( (hi<<8) | lo );
nixnax 142:54d1543e23e5 515 }
nixnax 142:54d1543e23e5 516 if (len&1) {
nixnax 142:54d1543e23e5 517 ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax 142:54d1543e23e5 518 }
nixnax 142:54d1543e23e5 519 sum = (sum & 0xffff) + (sum>>16);
nixnax 142:54d1543e23e5 520 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 142:54d1543e23e5 521 return ~sum;
nixnax 142:54d1543e23e5 522 }
nixnax 142:54d1543e23e5 523
nixnax 142:54d1543e23e5 524 /// perform the checksum on an IP header
nixnax 142:54d1543e23e5 525 void headerCheckSum()
nixnax 142:54d1543e23e5 526 {
nixnax 142:54d1543e23e5 527 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 142:54d1543e23e5 528 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 142:54d1543e23e5 529 int sum=0;
nixnax 142:54d1543e23e5 530
nixnax 142:54d1543e23e5 531 for (int i=0; i<len/2; i++) {
nixnax 142:54d1543e23e5 532 int hi = *ptr;
nixnax 142:54d1543e23e5 533 ptr++;
nixnax 142:54d1543e23e5 534 int lo = *ptr;
nixnax 142:54d1543e23e5 535 ptr++;
nixnax 142:54d1543e23e5 536 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 142:54d1543e23e5 537 sum = sum + val;
nixnax 142:54d1543e23e5 538 checkPc();
nixnax 142:54d1543e23e5 539 }
nixnax 142:54d1543e23e5 540 sum = sum + (sum>>16);
nixnax 142:54d1543e23e5 541 sum = ~sum;
nixnax 142:54d1543e23e5 542 ppp.pkt.buf[14]= (sum>>8);
nixnax 142:54d1543e23e5 543 ppp.pkt.buf[15]= (sum );
nixnax 142:54d1543e23e5 544 }
nixnax 142:54d1543e23e5 545
nixnax 142:54d1543e23e5 546 /// handle a PING ICMP (internet control message protocol) packet
nixnax 142:54d1543e23e5 547 void ICMPpacket() // internet control message protocol
nixnax 142:54d1543e23e5 548 {
nixnax 142:54d1543e23e5 549 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 142:54d1543e23e5 550 char * pktLen = ipPkt+2;
nixnax 142:54d1543e23e5 551 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 142:54d1543e23e5 552 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 142:54d1543e23e5 553 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 142:54d1543e23e5 554 char * icmpSum = icmpType+2; // icmp checksum
nixnax 142:54d1543e23e5 555 #define ICMP_TYPE_PING_REQUEST 8
nixnax 142:54d1543e23e5 556 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 142:54d1543e23e5 557 char * ipTTL = ipPkt+8; // time to live
nixnax 142:54d1543e23e5 558 ipTTL[0]--; // decrement time to live
nixnax 142:54d1543e23e5 559 char * srcAdr = ipPkt+12;
nixnax 142:54d1543e23e5 560 char * dstAdr = ipPkt+16;
nixnax 142:54d1543e23e5 561 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 562 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 142:54d1543e23e5 563 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 142:54d1543e23e5 564 if(1) {
nixnax 142:54d1543e23e5 565 char pbuf[50];
nixnax 142:54d1543e23e5 566 checkPc();
nixnax 142:54d1543e23e5 567 sprintf(pbuf, "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 142:54d1543e23e5 568 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 569 checkPc();
nixnax 142:54d1543e23e5 570 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 142:54d1543e23e5 571 checkPc();
nixnax 142:54d1543e23e5 572 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 573 }
nixnax 142:54d1543e23e5 574 #endif
nixnax 142:54d1543e23e5 575 char src[4];
nixnax 142:54d1543e23e5 576 char dst[4];
nixnax 142:54d1543e23e5 577 memcpy(src, srcAdr,4);
nixnax 142:54d1543e23e5 578 memcpy(dst, dstAdr,4);
nixnax 142:54d1543e23e5 579 memcpy(srcAdr, dst,4);
nixnax 142:54d1543e23e5 580 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 142:54d1543e23e5 581 char * chkSum = ipPkt+10;
nixnax 142:54d1543e23e5 582 chkSum[0]=0;
nixnax 142:54d1543e23e5 583 chkSum[1]=0;
nixnax 142:54d1543e23e5 584 headerCheckSum(); // new ip header checksum
nixnax 142:54d1543e23e5 585 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 142:54d1543e23e5 586 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 142:54d1543e23e5 587 icmpSum[0]=0;
nixnax 142:54d1543e23e5 588 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 142:54d1543e23e5 589 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 142:54d1543e23e5 590 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 142:54d1543e23e5 591 icmpSum[0]=(sum>>8)&0xff;
nixnax 142:54d1543e23e5 592 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 142:54d1543e23e5 593
nixnax 142:54d1543e23e5 594 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 142:54d1543e23e5 595 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 142:54d1543e23e5 596 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 142:54d1543e23e5 597 if (0) {
nixnax 142:54d1543e23e5 598 for (int i=0; i<printSize; i++) {
nixnax 142:54d1543e23e5 599 char ch = icmpData[i];
nixnax 142:54d1543e23e5 600 if (ch>31 && ch<127) {
nixnax 142:54d1543e23e5 601 putcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 602 } else {
nixnax 142:54d1543e23e5 603 putcWhileCheckingInput('_');
nixnax 142:54d1543e23e5 604 }
nixnax 142:54d1543e23e5 605 }
nixnax 142:54d1543e23e5 606 putcWhileCheckingInput('\n');
nixnax 142:54d1543e23e5 607 }
nixnax 142:54d1543e23e5 608 send_pppFrame(); // reply to the ping
nixnax 142:54d1543e23e5 609 } else {
nixnax 142:54d1543e23e5 610 if (v0) {
nixnax 142:54d1543e23e5 611 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 142:54d1543e23e5 612 }
nixnax 142:54d1543e23e5 613 }
nixnax 142:54d1543e23e5 614 }
nixnax 142:54d1543e23e5 615
nixnax 142:54d1543e23e5 616 /// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax 142:54d1543e23e5 617 void IGMPpacket()
nixnax 142:54d1543e23e5 618 {
nixnax 142:54d1543e23e5 619 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 142:54d1543e23e5 620 }
nixnax 142:54d1543e23e5 621
nixnax 142:54d1543e23e5 622 /// dump the header of an IP pakcet on the (optional) debug serial port
nixnax 142:54d1543e23e5 623 void dumpHeaderIP (int outGoing)
nixnax 142:54d1543e23e5 624 {
nixnax 142:54d1543e23e5 625 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 142:54d1543e23e5 626 checkPc(); // we are expecting the first character of the next packet
nixnax 142:54d1543e23e5 627 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 142:54d1543e23e5 628 char * ident = ipPkt+4; // 2 bytes
nixnax 142:54d1543e23e5 629 #ifdef UNUSED_IP_VARIABLES
nixnax 142:54d1543e23e5 630 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 142:54d1543e23e5 631 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 142:54d1543e23e5 632 char * version = ipPkt; // top 4 bits
nixnax 142:54d1543e23e5 633 char * ihl = ipPkt; // bottom 4 bits
nixnax 142:54d1543e23e5 634 char * dscp = ipPkt+1; // top 6 bits
nixnax 142:54d1543e23e5 635 char * ecn = ipPkt+1; // lower 2 bits
nixnax 142:54d1543e23e5 636 char * pktLen = ipPkt+2; // 2 bytes
nixnax 142:54d1543e23e5 637 char * flags = ipPkt+6; // 2 bits
nixnax 142:54d1543e23e5 638 char * ttl = ipPkt+8; // 1 byte
nixnax 142:54d1543e23e5 639 char * protocol = ipPkt+9; // 1 byte
nixnax 142:54d1543e23e5 640 char * headercheck= ipPkt+10; // 2 bytes
nixnax 142:54d1543e23e5 641 int versionIP = (version[0]>>4)&0xf;
nixnax 142:54d1543e23e5 642 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 142:54d1543e23e5 643 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 142:54d1543e23e5 644 int ecnIP = ecn[0]&3;
nixnax 142:54d1543e23e5 645 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 142:54d1543e23e5 646 int flagsIP = flags[0]>>14&3;
nixnax 142:54d1543e23e5 647 int ttlIP = ttl[0];
nixnax 142:54d1543e23e5 648 int protocolIP = protocol[0];
nixnax 142:54d1543e23e5 649 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 142:54d1543e23e5 650 #endif
nixnax 142:54d1543e23e5 651 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 142:54d1543e23e5 652 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 653 int n=0;
nixnax 142:54d1543e23e5 654 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 142:54d1543e23e5 655 n=n+sprintf(pbuf+n, "%05d ",IPv4Id); // IPv4Id is a good way to correlate our dumps with net monitor or wireshark traces
nixnax 142:54d1543e23e5 656 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 142:54d1543e23e5 657 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 142:54d1543e23e5 658 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 142:54d1543e23e5 659 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 142:54d1543e23e5 660 n=n+sprintf(pbuf+n, " %d.%d.%d.%d %d.%d.%d.%d ",srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3], dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]); // full ip addresses
nixnax 142:54d1543e23e5 661 #endif
nixnax 142:54d1543e23e5 662 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 663 #ifndef TCP_HEADER_DUMP_YES
nixnax 142:54d1543e23e5 664 putsWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 142:54d1543e23e5 665 #endif
nixnax 142:54d1543e23e5 666 #endif
nixnax 142:54d1543e23e5 667 }
nixnax 142:54d1543e23e5 668
nixnax 142:54d1543e23e5 669 /// dump a TCP header on the optional debug serial port
nixnax 142:54d1543e23e5 670 void dumpHeaderTCP(int outGoing)
nixnax 142:54d1543e23e5 671 {
nixnax 142:54d1543e23e5 672 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 142:54d1543e23e5 673 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 142:54d1543e23e5 674 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 142:54d1543e23e5 675 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 142:54d1543e23e5 676 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 142:54d1543e23e5 677 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 142:54d1543e23e5 678 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 142:54d1543e23e5 679 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 142:54d1543e23e5 680 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 142:54d1543e23e5 681 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 142:54d1543e23e5 682 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 142:54d1543e23e5 683 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 142:54d1543e23e5 684 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 142:54d1543e23e5 685 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 142:54d1543e23e5 686 flagInfo[8]=0; // null terminate string
nixnax 142:54d1543e23e5 687 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 142:54d1543e23e5 688 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 142:54d1543e23e5 689 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 142:54d1543e23e5 690 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 142:54d1543e23e5 691 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 142:54d1543e23e5 692 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 142:54d1543e23e5 693 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 142:54d1543e23e5 694 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 142:54d1543e23e5 695 #else
nixnax 142:54d1543e23e5 696 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 142:54d1543e23e5 697 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 142:54d1543e23e5 698 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 142:54d1543e23e5 699 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 142:54d1543e23e5 700 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 142:54d1543e23e5 701 flagInfo[1]=0; // ' '
nixnax 142:54d1543e23e5 702 flagInfo[2]=0;
nixnax 142:54d1543e23e5 703 #endif
nixnax 142:54d1543e23e5 704 putsWhileCheckingInput( flagInfo );
nixnax 142:54d1543e23e5 705 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 706 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 707 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 142:54d1543e23e5 708 #endif
nixnax 142:54d1543e23e5 709 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 142:54d1543e23e5 710 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 142:54d1543e23e5 711 }
nixnax 142:54d1543e23e5 712 #endif
nixnax 142:54d1543e23e5 713 }
nixnax 142:54d1543e23e5 714
nixnax 142:54d1543e23e5 715 ///
nixnax 142:54d1543e23e5 716 void enc64(char * in, char * out, int len)
nixnax 142:54d1543e23e5 717 {
nixnax 142:54d1543e23e5 718 const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax 142:54d1543e23e5 719 int i,j,a,b,c;
nixnax 142:54d1543e23e5 720 i=0;
nixnax 142:54d1543e23e5 721 j=0;
nixnax 142:54d1543e23e5 722 while(1) {
nixnax 142:54d1543e23e5 723 if (i<len) {
nixnax 142:54d1543e23e5 724 a = in[i++];
nixnax 142:54d1543e23e5 725 out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax 142:54d1543e23e5 726 } else break;
nixnax 142:54d1543e23e5 727 if (i<len) {
nixnax 142:54d1543e23e5 728 b = in[i++];
nixnax 142:54d1543e23e5 729 out[j++] = lut[ ( (a << 4) & 0x30) | ( (b >> 4) & 0x0f) ];
nixnax 142:54d1543e23e5 730 out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax 142:54d1543e23e5 731 } else out[j++] = '=';
nixnax 142:54d1543e23e5 732 if (i<len) {
nixnax 142:54d1543e23e5 733 c = in[i++];
nixnax 142:54d1543e23e5 734 j--;
nixnax 142:54d1543e23e5 735 out[j++] = lut[ ( (b << 2) & 0x3c) | ( (c >> 6) & 0x03) ];
nixnax 142:54d1543e23e5 736 out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax 142:54d1543e23e5 737 } else out[j++] = '=';
nixnax 142:54d1543e23e5 738 }
nixnax 142:54d1543e23e5 739 out[j]=0;
nixnax 142:54d1543e23e5 740 }
nixnax 142:54d1543e23e5 741
nixnax 142:54d1543e23e5 742 /// handle a request for an http websocket
nixnax 142:54d1543e23e5 743 /// we end up here if we enter the following javascript in a web browser console: x = new WebSocket("ws://172.10.10.2");
nixnax 142:54d1543e23e5 744 int webSocketHandler(char * dataStart)
nixnax 142:54d1543e23e5 745 {
nixnax 142:54d1543e23e5 746 int n=0; // byte counter
nixnax 142:54d1543e23e5 747 char * key = strstr(dataStart, "Sec-WebSocket-Key: "); // search for the key in the payload
nixnax 142:54d1543e23e5 748 if (key != NULL) {
nixnax 142:54d1543e23e5 749 if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax 142:54d1543e23e5 750 char challenge [70];
nixnax 142:54d1543e23e5 751 strncpy(challenge,key+19,70); // a local buffer
nixnax 142:54d1543e23e5 752 *strchr(challenge,'\r')=0; // insert null so we can use sprintf
nixnax 142:54d1543e23e5 753 strncat(challenge,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11",70); // append websocket gui code
nixnax 142:54d1543e23e5 754 char shaOutput [20]; // sha1 output
nixnax 142:54d1543e23e5 755 sha1( shaOutput, challenge, strlen(challenge));
nixnax 142:54d1543e23e5 756 char encOut[50];
nixnax 142:54d1543e23e5 757 enc64( shaOutput, encOut, 20);
nixnax 142:54d1543e23e5 758 char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax 142:54d1543e23e5 759 char * version = challenge;
nixnax 142:54d1543e23e5 760 strncpy(version, versionstring,70); // copy version string
nixnax 142:54d1543e23e5 761 *strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax 142:54d1543e23e5 762 memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax 142:54d1543e23e5 763 n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax 142:54d1543e23e5 764 n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax 142:54d1543e23e5 765 n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax 142:54d1543e23e5 766 n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax 142:54d1543e23e5 767 n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax 142:54d1543e23e5 768 n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax 142:54d1543e23e5 769 n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax 142:54d1543e23e5 770 }
nixnax 142:54d1543e23e5 771 return n; // this response should satisfy a web browser's websocket protocol request
nixnax 142:54d1543e23e5 772 }
nixnax 142:54d1543e23e5 773
nixnax 142:54d1543e23e5 774 #define TCP_FLAG_ACK (1<<4)
nixnax 142:54d1543e23e5 775 #define TCP_FLAG_SYN (1<<1)
nixnax 142:54d1543e23e5 776 #define TCP_FLAG_PSH (1<<3)
nixnax 142:54d1543e23e5 777 #define TCP_FLAG_RST (1<<2)
nixnax 142:54d1543e23e5 778 #define TCP_FLAG_FIN (1<<0)
nixnax 142:54d1543e23e5 779
nixnax 142:54d1543e23e5 780 /// respond to an HTTP request
nixnax 142:54d1543e23e5 781 int httpResponse(char * dataStart)
nixnax 142:54d1543e23e5 782 {
nixnax 142:54d1543e23e5 783 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 784 n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax 142:54d1543e23e5 785 if (n>0) return n; // if it's a WebSocket we already have the response, so return
nixnax 142:54d1543e23e5 786
nixnax 142:54d1543e23e5 787 int nHeader; // byte size of HTTP header
nixnax 142:54d1543e23e5 788 int contentLengthStart; // index where HTML starts
nixnax 142:54d1543e23e5 789 int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax 142:54d1543e23e5 790
nixnax 142:54d1543e23e5 791 ppp.httpPageCount++; // increment the number of frames we have made
nixnax 142:54d1543e23e5 792
nixnax 142:54d1543e23e5 793 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax 142:54d1543e23e5 794 httpGetx = strncmp(dataStart, "GET /x", 6); // found a GET to /x which we will treat special (anything starting with /x, e.g. /x, /xyz, /xABC?pqr=123
nixnax 142:54d1543e23e5 795 httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 796 httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 797 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 142:54d1543e23e5 798 if( (httpGetRoot==0) || (httpGetx==0) ) {
nixnax 142:54d1543e23e5 799 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax 142:54d1543e23e5 800 } else {
nixnax 142:54d1543e23e5 801 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 142:54d1543e23e5 802 }
nixnax 142:54d1543e23e5 803 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 142:54d1543e23e5 804 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 142:54d1543e23e5 805 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 142:54d1543e23e5 806 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 142:54d1543e23e5 807 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 142:54d1543e23e5 808 nHeader=n; // size of HTTP header
nixnax 142:54d1543e23e5 809 if( httpGetRoot == 0 ) {
nixnax 142:54d1543e23e5 810 // this is where we insert our web page into the buffer
nixnax 142:54d1543e23e5 811 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 142:54d1543e23e5 812 n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax 142:54d1543e23e5 813 } else if ( (httpGet5 == 'w') && (httpGet6 == 's') ) { // "ws" is a special page for websocket demo
nixnax 142:54d1543e23e5 814 memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax 142:54d1543e23e5 815 n = n + sizeof(webSocketPage)-1; // one less than size
nixnax 142:54d1543e23e5 816 } else {
nixnax 142:54d1543e23e5 817 if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax 142:54d1543e23e5 818
nixnax 142:54d1543e23e5 819 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 142:54d1543e23e5 820 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 142:54d1543e23e5 821 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 142:54d1543e23e5 822 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax 142:54d1543e23e5 823 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.httpPageCount); // body = the http frame count
nixnax 142:54d1543e23e5 824 #else
nixnax 142:54d1543e23e5 825 if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax 142:54d1543e23e5 826 n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax 142:54d1543e23e5 827 }
nixnax 142:54d1543e23e5 828 // /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax 142:54d1543e23e5 829 n=n+sprintf(n+dataStart,"%d ",ppp.httpPageCount); // not really valid html but most browsers and curl are ok with it
nixnax 142:54d1543e23e5 830 #endif
nixnax 142:54d1543e23e5 831 } else {
nixnax 142:54d1543e23e5 832 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 142:54d1543e23e5 833 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax 142:54d1543e23e5 834 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 142:54d1543e23e5 835 }
nixnax 142:54d1543e23e5 836 }
nixnax 142:54d1543e23e5 837 #define CONTENTLENGTHSIZE 5
nixnax 142:54d1543e23e5 838 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 142:54d1543e23e5 839 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 142:54d1543e23e5 840 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 142:54d1543e23e5 841 return n; // total byte size of our response
nixnax 142:54d1543e23e5 842 }
nixnax 142:54d1543e23e5 843
nixnax 142:54d1543e23e5 844 /// handle TCP data that is not an HTTP get
nixnax 142:54d1543e23e5 845 /// this is the response if we have TCP data but it's not an HTTP GET
nixnax 142:54d1543e23e5 846 /// this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 142:54d1543e23e5 847 /// this could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax 142:54d1543e23e5 848 int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax 142:54d1543e23e5 849 {
nixnax 142:54d1543e23e5 850 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 851 if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax 142:54d1543e23e5 852 // this is most likely a websocket push message. you get this when you enter this in your browser console: x.send("my message");
nixnax 142:54d1543e23e5 853 if (0) putsWhileCheckingInput( "Got data from websocket send()\n" );
nixnax 142:54d1543e23e5 854
nixnax 142:54d1543e23e5 855 // for now we simply echo the websocket data back to the client - the client should therefore see an onmessage event
nixnax 142:54d1543e23e5 856 // to display the echoed data in your browser, enter the following into the browser console: x.onmessage = function(msg){ console.log( msg.data ); }
nixnax 142:54d1543e23e5 857 if (1) {
nixnax 142:54d1543e23e5 858 char mask [4];
nixnax 142:54d1543e23e5 859 memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax 142:54d1543e23e5 860 int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax 142:54d1543e23e5 861 if((dataStart[1]&0x80)==0x80) // test if the mask bit is set, which means all data is xor'ed with the mask
nixnax 142:54d1543e23e5 862 for (int i=0; i<websocketMessageSize; i++) dataStart[i+6]^= mask[i%4]; // unmask each byte with one of the mask bytes
nixnax 142:54d1543e23e5 863 dataStart[1] = len-2; // add four extra bytes to the message length because we don't use mask bytes for the send
nixnax 142:54d1543e23e5 864 memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax 142:54d1543e23e5 865 n = len; // our response size remains exactly the same length as what we received
nixnax 142:54d1543e23e5 866 }
nixnax 142:54d1543e23e5 867 } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax 142:54d1543e23e5 868 n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax 142:54d1543e23e5 869 dataStart[1]=0; // we don't have mask bytes on
nixnax 142:54d1543e23e5 870 } else if (v1) putsWhileCheckingInput("TCP data received\n");
nixnax 142:54d1543e23e5 871 return n; // total byte size of our response
nixnax 142:54d1543e23e5 872 }
nixnax 142:54d1543e23e5 873
nixnax 142:54d1543e23e5 874 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 875 /// use the first few bytes to figure out if it's a websocket, an http request or just pure incoming TCP data
nixnax 142:54d1543e23e5 876 void tcpHandler()
nixnax 142:54d1543e23e5 877 {
nixnax 142:54d1543e23e5 878 // IP header
nixnax 142:54d1543e23e5 879 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 142:54d1543e23e5 880 char * ihl = ipPkt; // bottom 4 bits
nixnax 142:54d1543e23e5 881 char * pktLen = ipPkt+2; // 2 bytes
nixnax 142:54d1543e23e5 882 char * ident = ipPkt+4; // 2 bytes
nixnax 142:54d1543e23e5 883 char * protocol = ipPkt+9; // 1 byte
nixnax 142:54d1543e23e5 884 char * headercheck= ipPkt+10; // 2 bytes
nixnax 142:54d1543e23e5 885 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 142:54d1543e23e5 886 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 142:54d1543e23e5 887 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 142:54d1543e23e5 888 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 142:54d1543e23e5 889
nixnax 142:54d1543e23e5 890 // TCP header
nixnax 142:54d1543e23e5 891 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 142:54d1543e23e5 892 char * srctcp = tcp + 0; // 2 bytes
nixnax 142:54d1543e23e5 893 char * dsttcp = tcp + 2; // 2 bytes
nixnax 142:54d1543e23e5 894 char * seqtcp = tcp + 4; // 4 bytes
nixnax 142:54d1543e23e5 895 char * acktcp = tcp + 8; // 4 bytes
nixnax 142:54d1543e23e5 896 char * offset = tcp + 12; // 4 bits
nixnax 142:54d1543e23e5 897 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 142:54d1543e23e5 898 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 142:54d1543e23e5 899 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 142:54d1543e23e5 900
nixnax 142:54d1543e23e5 901 if(ident) {}; // shut up unused variable reference warning
nixnax 142:54d1543e23e5 902 int tcpSize = packetLength - headerSizeIP;
nixnax 142:54d1543e23e5 903 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 142:54d1543e23e5 904 int protocolIP = protocol[0];
nixnax 142:54d1543e23e5 905 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 142:54d1543e23e5 906 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 142:54d1543e23e5 907 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 142:54d1543e23e5 908 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 142:54d1543e23e5 909 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 142:54d1543e23e5 910 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 142:54d1543e23e5 911 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 142:54d1543e23e5 912
nixnax 142:54d1543e23e5 913 // first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax 142:54d1543e23e5 914 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 142:54d1543e23e5 915 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 142:54d1543e23e5 916 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 142:54d1543e23e5 917 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 142:54d1543e23e5 918 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 142:54d1543e23e5 919 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 142:54d1543e23e5 920
nixnax 142:54d1543e23e5 921 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 142:54d1543e23e5 922 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 142:54d1543e23e5 923 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 142:54d1543e23e5 924 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 142:54d1543e23e5 925 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 142:54d1543e23e5 926
nixnax 142:54d1543e23e5 927 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 142:54d1543e23e5 928
nixnax 142:54d1543e23e5 929 switch ( flagsTCP ) {
nixnax 142:54d1543e23e5 930 case TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 931 return;
nixnax 142:54d1543e23e5 932 case TCP_FLAG_SYN:
nixnax 142:54d1543e23e5 933 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 142:54d1543e23e5 934 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 142:54d1543e23e5 935 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 936 break;
nixnax 142:54d1543e23e5 937 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 142:54d1543e23e5 938 if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax 142:54d1543e23e5 939 flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // set outgoing FIN flag to ask them to close from their side
nixnax 142:54d1543e23e5 940 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 142:54d1543e23e5 941 } else {
nixnax 142:54d1543e23e5 942 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not a web request, send a packet reporting number of received bytes
nixnax 142:54d1543e23e5 943 }
nixnax 142:54d1543e23e5 944 break;
nixnax 142:54d1543e23e5 945 case TCP_FLAG_FIN:
nixnax 142:54d1543e23e5 946 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 947 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 948 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 142:54d1543e23e5 949 ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 950 break;
nixnax 142:54d1543e23e5 951 default:
nixnax 142:54d1543e23e5 952 return; // ignore remaining packets
nixnax 142:54d1543e23e5 953 } // switch
nixnax 142:54d1543e23e5 954
nixnax 142:54d1543e23e5 955 // The TCP flag handling is now done
nixnax 142:54d1543e23e5 956 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 142:54d1543e23e5 957 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 142:54d1543e23e5 958 memcpy(tempHold, srcAdr,4);
nixnax 142:54d1543e23e5 959 memcpy(srcAdr, dstAdr,4);
nixnax 142:54d1543e23e5 960 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 142:54d1543e23e5 961 memcpy(tempHold, srctcp,2);
nixnax 142:54d1543e23e5 962 memcpy(srctcp, dsttcp,2);
nixnax 142:54d1543e23e5 963 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 142:54d1543e23e5 964
nixnax 142:54d1543e23e5 965 acktcp[0]=ack_out>>24;
nixnax 142:54d1543e23e5 966 acktcp[1]=ack_out>>16;
nixnax 142:54d1543e23e5 967 acktcp[2]=ack_out>>8;
nixnax 142:54d1543e23e5 968 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 142:54d1543e23e5 969 seqtcp[0]=seq_out>>24;
nixnax 142:54d1543e23e5 970 seqtcp[1]=seq_out>>16;
nixnax 142:54d1543e23e5 971 seqtcp[2]=seq_out>>8;
nixnax 142:54d1543e23e5 972 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 142:54d1543e23e5 973
nixnax 142:54d1543e23e5 974 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 142:54d1543e23e5 975
nixnax 142:54d1543e23e5 976 // increment our outgoing ip packet counter
nixnax 142:54d1543e23e5 977 ppp.ip.ident++; // get next ident number for our packet
nixnax 142:54d1543e23e5 978
nixnax 142:54d1543e23e5 979 // Now we recalculate all the header sizes
nixnax 142:54d1543e23e5 980 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 142:54d1543e23e5 981 int newPacketSize = headerSizeIP + tcpSize; // calculate size of the outgoing packet
nixnax 142:54d1543e23e5 982 pktLen[0] = (newPacketSize>>8);
nixnax 142:54d1543e23e5 983 pktLen[1]=newPacketSize; // ip total packet size
nixnax 142:54d1543e23e5 984 ppp.pkt.len = newPacketSize+4+2; // ip packet length + 4-byte ppp prefix (ff 03 00 21) + 2 fcs (crc) bytes bytes at the end of the packet
nixnax 142:54d1543e23e5 985
nixnax 142:54d1543e23e5 986 // the header is all set up, now do the IP and TCP checksums
nixnax 142:54d1543e23e5 987 headercheck[0]=0; // IP header checksum
nixnax 142:54d1543e23e5 988 headercheck[1]=0; // IP header checksum
nixnax 142:54d1543e23e5 989 headerCheckSum(); // calculate the IP header checksum
nixnax 142:54d1543e23e5 990
nixnax 142:54d1543e23e5 991 // 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 142:54d1543e23e5 992 // this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax 142:54d1543e23e5 993 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 142:54d1543e23e5 994 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 142:54d1543e23e5 995 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 142:54d1543e23e5 996 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 142:54d1543e23e5 997 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 142:54d1543e23e5 998 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 142:54d1543e23e5 999 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 142:54d1543e23e5 1000
nixnax 142:54d1543e23e5 1001 // pseudo-header built, now we can calculate TCP checksum
nixnax 142:54d1543e23e5 1002 checksumtcp[0]=0;
nixnax 142:54d1543e23e5 1003 checksumtcp[1]=0;
nixnax 142:54d1543e23e5 1004 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 142:54d1543e23e5 1005 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 142:54d1543e23e5 1006 checksumtcp[1]=pseudoHeaderSum;
nixnax 142:54d1543e23e5 1007 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 142:54d1543e23e5 1008 dumpHeaderIP(1); // dump outgoing IP header
nixnax 142:54d1543e23e5 1009 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 142:54d1543e23e5 1010 for (int i=0; i<45*1000/10; i++) { // 45 ms delay before sending frame - a typical internet delay time
nixnax 142:54d1543e23e5 1011 checkPc(); // catch any incoming characters
nixnax 142:54d1543e23e5 1012 wait_us(10); // wait less than 1 character duration at 115200
nixnax 142:54d1543e23e5 1013 }
nixnax 142:54d1543e23e5 1014 send_pppFrame(); // All preparation complete - send the TCP response
nixnax 142:54d1543e23e5 1015 if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
nixnax 142:54d1543e23e5 1016 memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax 142:54d1543e23e5 1017 }
nixnax 142:54d1543e23e5 1018
nixnax 142:54d1543e23e5 1019
nixnax 142:54d1543e23e5 1020 /// dump the TCP data to the debug serial port
nixnax 142:54d1543e23e5 1021 void dumpDataTCP()
nixnax 142:54d1543e23e5 1022 {
nixnax 142:54d1543e23e5 1023 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 142:54d1543e23e5 1024 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 142:54d1543e23e5 1025 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 142:54d1543e23e5 1026 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 142:54d1543e23e5 1027 if (v1) {
nixnax 142:54d1543e23e5 1028 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 1029 checkPc();
nixnax 142:54d1543e23e5 1030 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 142:54d1543e23e5 1031 checkPc();
nixnax 142:54d1543e23e5 1032 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 1033 }
nixnax 142:54d1543e23e5 1034 if (dataLen > 0) {
nixnax 142:54d1543e23e5 1035 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 142:54d1543e23e5 1036 putsWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP ); // print the tcp payload data
nixnax 142:54d1543e23e5 1037 putsWhileCheckingInput("\n");
nixnax 142:54d1543e23e5 1038 }
nixnax 142:54d1543e23e5 1039 }
nixnax 142:54d1543e23e5 1040
nixnax 142:54d1543e23e5 1041 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 1042 void TCPpacket()
nixnax 142:54d1543e23e5 1043 {
nixnax 142:54d1543e23e5 1044 dumpHeaderIP(0); // dump incoming packet header
nixnax 142:54d1543e23e5 1045 dumpHeaderTCP(0); // dump incoming packet header
nixnax 142:54d1543e23e5 1046 if (v2) dumpDataTCP();
nixnax 142:54d1543e23e5 1047 tcpHandler();
nixnax 142:54d1543e23e5 1048 }
nixnax 142:54d1543e23e5 1049
nixnax 142:54d1543e23e5 1050 /// handle the remaining IP protocols by ignoring them
nixnax 142:54d1543e23e5 1051 void otherProtocol()
nixnax 142:54d1543e23e5 1052 {
nixnax 142:54d1543e23e5 1053 debugPrintf("Other IP protocol");
nixnax 142:54d1543e23e5 1054 }
nixnax 142:54d1543e23e5 1055
nixnax 142:54d1543e23e5 1056 /// process an incoming IP packet
nixnax 142:54d1543e23e5 1057 void IPframe()
nixnax 142:54d1543e23e5 1058 {
nixnax 142:54d1543e23e5 1059 int protocol = ppp.pkt.buf[13];
nixnax 142:54d1543e23e5 1060 switch (protocol) {
nixnax 142:54d1543e23e5 1061 case 1:
nixnax 142:54d1543e23e5 1062 ICMPpacket();
nixnax 142:54d1543e23e5 1063 break;
nixnax 142:54d1543e23e5 1064 case 2:
nixnax 142:54d1543e23e5 1065 IGMPpacket();
nixnax 142:54d1543e23e5 1066 break;
nixnax 142:54d1543e23e5 1067 case 17:
nixnax 142:54d1543e23e5 1068 UDPpacket();
nixnax 142:54d1543e23e5 1069 break;
nixnax 142:54d1543e23e5 1070 case 6:
nixnax 142:54d1543e23e5 1071 TCPpacket();
nixnax 142:54d1543e23e5 1072 break;
nixnax 142:54d1543e23e5 1073 default:
nixnax 142:54d1543e23e5 1074 otherProtocol();
nixnax 142:54d1543e23e5 1075 }
nixnax 142:54d1543e23e5 1076 }
nixnax 142:54d1543e23e5 1077
nixnax 142:54d1543e23e5 1078 /// respond to LCP (line configuration protocol) configuration request) by allowing no options
nixnax 142:54d1543e23e5 1079 void LCPconfReq()
nixnax 142:54d1543e23e5 1080 {
nixnax 142:54d1543e23e5 1081 debugPrintf("LCP Config ");
nixnax 142:54d1543e23e5 1082 if (ppp.pkt.buf[7] != 4) {
nixnax 142:54d1543e23e5 1083 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 142:54d1543e23e5 1084 debugPrintf("Reject\n");
nixnax 142:54d1543e23e5 1085 send_pppFrame();
nixnax 142:54d1543e23e5 1086 } else {
nixnax 142:54d1543e23e5 1087 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 142:54d1543e23e5 1088 debugPrintf("Ack\n");
nixnax 142:54d1543e23e5 1089 send_pppFrame();
nixnax 142:54d1543e23e5 1090 debugPrintf("LCP Ask\n");
nixnax 142:54d1543e23e5 1091 ppp.pkt.buf[4]=1; // request no options
nixnax 142:54d1543e23e5 1092 send_pppFrame();
nixnax 142:54d1543e23e5 1093 }
nixnax 142:54d1543e23e5 1094 }
nixnax 142:54d1543e23e5 1095
nixnax 142:54d1543e23e5 1096 /// handle LCP acknowledge packets by ignoring them
nixnax 142:54d1543e23e5 1097 void LCPconfAck()
nixnax 142:54d1543e23e5 1098 {
nixnax 142:54d1543e23e5 1099 debugPrintf("LCP Ack\n");
nixnax 142:54d1543e23e5 1100 }
nixnax 142:54d1543e23e5 1101
nixnax 142:54d1543e23e5 1102 /// handle LCP end packets by acknowledging them and by setting ppp.online to false
nixnax 142:54d1543e23e5 1103 void LCPend()
nixnax 142:54d1543e23e5 1104 {
nixnax 142:54d1543e23e5 1105 ppp.pkt.buf[4]=6;
nixnax 142:54d1543e23e5 1106 send_pppFrame(); // acknowledge
nixnax 142:54d1543e23e5 1107 ppp.online=0; // start hunting for connect string again
nixnax 142:54d1543e23e5 1108 pppInitStruct(); // flush the receive buffer
nixnax 142:54d1543e23e5 1109 debugPrintf("LCP End\n");
nixnax 142:54d1543e23e5 1110 }
nixnax 142:54d1543e23e5 1111
nixnax 142:54d1543e23e5 1112 /// respond to other LCP requests by ignoring them
nixnax 142:54d1543e23e5 1113 void LCPother()
nixnax 142:54d1543e23e5 1114 {
nixnax 142:54d1543e23e5 1115 debugPrintf("LCP Other\n");
nixnax 142:54d1543e23e5 1116 dumpPPPFrame();
nixnax 142:54d1543e23e5 1117 }
nixnax 142:54d1543e23e5 1118
nixnax 142:54d1543e23e5 1119 /// process incoming LCP packets
nixnax 142:54d1543e23e5 1120 void LCPframe()
nixnax 142:54d1543e23e5 1121 {
nixnax 142:54d1543e23e5 1122 int code = ppp.pkt.buf[4];
nixnax 142:54d1543e23e5 1123 switch (code) {
nixnax 142:54d1543e23e5 1124 case 1:
nixnax 142:54d1543e23e5 1125 LCPconfReq();
nixnax 142:54d1543e23e5 1126 break; // config request
nixnax 142:54d1543e23e5 1127 case 2:
nixnax 142:54d1543e23e5 1128 LCPconfAck();
nixnax 142:54d1543e23e5 1129 break; // config ack
nixnax 142:54d1543e23e5 1130 case 5:
nixnax 142:54d1543e23e5 1131 LCPend();
nixnax 142:54d1543e23e5 1132 break; // end connection
nixnax 142:54d1543e23e5 1133 default:
nixnax 142:54d1543e23e5 1134 LCPother();
nixnax 142:54d1543e23e5 1135 }
nixnax 142:54d1543e23e5 1136 }
nixnax 142:54d1543e23e5 1137
nixnax 142:54d1543e23e5 1138 /// discard packets that are not IP, IPCP, or LCP
nixnax 142:54d1543e23e5 1139 void discardedFrame()
nixnax 142:54d1543e23e5 1140 {
nixnax 142:54d1543e23e5 1141 if (v0) debugPrintf("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 142:54d1543e23e5 1142 }
nixnax 142:54d1543e23e5 1143
nixnax 142:54d1543e23e5 1144 /// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax 142:54d1543e23e5 1145 void determinePacketType()
nixnax 142:54d1543e23e5 1146 {
nixnax 142:54d1543e23e5 1147 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 142:54d1543e23e5 1148 debugPrintf("byte0 != ff\n");
nixnax 142:54d1543e23e5 1149 return;
nixnax 142:54d1543e23e5 1150 }
nixnax 142:54d1543e23e5 1151 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 142:54d1543e23e5 1152 debugPrintf("byte1 != 3\n");
nixnax 142:54d1543e23e5 1153 return;
nixnax 142:54d1543e23e5 1154 }
nixnax 142:54d1543e23e5 1155 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 142:54d1543e23e5 1156 debugPrintf("byte2 != 21\n");
nixnax 142:54d1543e23e5 1157 return;
nixnax 142:54d1543e23e5 1158 }
nixnax 142:54d1543e23e5 1159 int packetType = ppp.pkt.buf[2];
nixnax 142:54d1543e23e5 1160 switch (packetType) {
nixnax 142:54d1543e23e5 1161 case 0xc0:
nixnax 142:54d1543e23e5 1162 LCPframe();
nixnax 142:54d1543e23e5 1163 break; // link control
nixnax 142:54d1543e23e5 1164 case 0x80:
nixnax 142:54d1543e23e5 1165 IPCPframe();
nixnax 142:54d1543e23e5 1166 break; // IP control
nixnax 142:54d1543e23e5 1167 case 0x00:
nixnax 142:54d1543e23e5 1168 IPframe();
nixnax 142:54d1543e23e5 1169 break; // IP itself
nixnax 142:54d1543e23e5 1170 default:
nixnax 142:54d1543e23e5 1171 discardedFrame();
nixnax 142:54d1543e23e5 1172 }
nixnax 142:54d1543e23e5 1173 }
nixnax 142:54d1543e23e5 1174
nixnax 142:54d1543e23e5 1175 /// scan the PPP serial input stream for frame start markers
nixnax 142:54d1543e23e5 1176 void waitForPppFrame()
nixnax 142:54d1543e23e5 1177 {
nixnax 142:54d1543e23e5 1178 while(1) {
nixnax 142:54d1543e23e5 1179 checkPc(); // handle received characters
nixnax 142:54d1543e23e5 1180 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 142:54d1543e23e5 1181 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 142:54d1543e23e5 1182 int rx = pc_getBuf(); // get the character
nixnax 142:54d1543e23e5 1183 if (rx==FRAME_7E) {
nixnax 142:54d1543e23e5 1184 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 142:54d1543e23e5 1185 ppp.firstFrame=0;
nixnax 142:54d1543e23e5 1186 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1187 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 142:54d1543e23e5 1188 } else {
nixnax 142:54d1543e23e5 1189 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 142:54d1543e23e5 1190 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 142:54d1543e23e5 1191 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1192 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax 142:54d1543e23e5 1193 break;
nixnax 142:54d1543e23e5 1194 }
nixnax 142:54d1543e23e5 1195 }
nixnax 142:54d1543e23e5 1196 }
nixnax 142:54d1543e23e5 1197 }
nixnax 142:54d1543e23e5 1198 }
nixnax 142:54d1543e23e5 1199
nixnax 142:54d1543e23e5 1200 /// scan for a connect string ("CLIENT") from the host PC, if found, we set ppp.oline to true, which will the IP packet scanner
nixnax 142:54d1543e23e5 1201 void scanForConnectString()
nixnax 142:54d1543e23e5 1202 {
nixnax 142:54d1543e23e5 1203 while(ppp.online == 0) {
nixnax 142:54d1543e23e5 1204 checkPc(); // gather received characters
nixnax 142:54d1543e23e5 1205 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 142:54d1543e23e5 1206 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 142:54d1543e23e5 1207 if (found1 != NULL) {
nixnax 142:54d1543e23e5 1208 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 142:54d1543e23e5 1209 if (v0) debugPrintf("Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 142:54d1543e23e5 1210 pc.puts("CLIENTSERVER");
nixnax 142:54d1543e23e5 1211 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 142:54d1543e23e5 1212 checkPc();
nixnax 142:54d1543e23e5 1213 }
nixnax 142:54d1543e23e5 1214 }
nixnax 142:54d1543e23e5 1215 }
nixnax 142:54d1543e23e5 1216
nixnax 142:54d1543e23e5 1217 /// set the PPP and debug baud rates and initialize data structures
nixnax 142:54d1543e23e5 1218 void initialize()
nixnax 142:54d1543e23e5 1219 {
nixnax 142:54d1543e23e5 1220 pc.baud(115200); // USB serial port to pc
nixnax 142:54d1543e23e5 1221 debugBaudRate(115200); // baud rate for our (optional) debug port
nixnax 142:54d1543e23e5 1222 debugPrintf("\x1b[2J\x1b[H\x1b[30mmbed PPP-Blinky HTTP & WebSocket server ready :)\n"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
nixnax 142:54d1543e23e5 1223 pppInitStruct(); // initialize all the PPP properties
nixnax 142:54d1543e23e5 1224 }
nixnax 142:54d1543e23e5 1225
nixnax 142:54d1543e23e5 1226 /*
nixnax 142:54d1543e23e5 1227 /// initialize, wait for the connect message, then start processing PPP frames
nixnax 142:54d1543e23e5 1228 int main()
nixnax 142:54d1543e23e5 1229 {
nixnax 142:54d1543e23e5 1230 initialize();
nixnax 142:54d1543e23e5 1231 while(1) {
nixnax 142:54d1543e23e5 1232 scanForConnectString(); // wait for connect from PC dial-up networking
nixnax 142:54d1543e23e5 1233 while(ppp.online) {
nixnax 142:54d1543e23e5 1234 waitForPppFrame(); // wait for a PPP frame
nixnax 142:54d1543e23e5 1235 }
nixnax 142:54d1543e23e5 1236 }
nixnax 142:54d1543e23e5 1237 }
nixnax 142:54d1543e23e5 1238 */