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@140:f526e9ecfebb, 2017-08-23 (annotated)

Committer:
nixnax
Date:
Wed Aug 23 21:54:47 2017 +0000
Revision:
140:f526e9ecfebb
Parent:
139:1f87c6bc8db3
Child:
141:4cc1518ee06f
Toggle LED only every second PPP packet.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 93:9675adc36882 1 // PPP-Blinky - "The Most Basic Internet Of Things"
nixnax 0:2cf4880c312a 2
nixnax 128:e5958d143e9d 3 // A Tiny HTTP Webserver Using Windows XP/7/8/10/Linux Dial-Up Networking Over A Serial Port.
nixnax 41:e58a5a09f411 4 // Also receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 128:e5958d143e9d 5 // Also: WebSocket Service - see https://en.wikipedia.org/wiki/WebSocket
nixnax 4:a469050d5b80 6
nixnax 93:9675adc36882 7 // 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 81:9ede60e9a2c8 8
nixnax 41:e58a5a09f411 9 // Notes and Instructions
nixnax 41:e58a5a09f411 10 // http://bit.ly/PPP-Blinky-Instructions
nixnax 114:8a5d70bbc1b2 11 // http://bit.ly/win-rasdial-config
nixnax 0:2cf4880c312a 12
nixnax 41:e58a5a09f411 13 // Handy reading material
nixnax 6:fba4c2e817b8 14 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 15 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 39:b90183d35f1e 16 // http://bit.ly/dialup777error - how to solve Dial Up Error 777 in Windows 7/8/10
nixnax 41:e58a5a09f411 17 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 18
nixnax 29:30de79d658f6 19 // Handy tools
nixnax 44:d0c61ae49ea5 20 // 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 109:644a59ebb5b1 21 // https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax 29:30de79d658f6 22 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 95:40af49390daf 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), then custom relected-in=1, reflected-out=1
nixnax 29:30de79d658f6 24 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 41:e58a5a09f411 25 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 91:5141ae9fba53 26 // 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 41:e58a5a09f411 27
nixnax 92:cb962b365cce 28 // Connecting PPP-Blinky to Linux
nixnax 93:9675adc36882 29 // PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax 93:9675adc36882 30 // pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax 92:cb962b365cce 31 // in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax 93:9675adc36882 32 // See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax 93:9675adc36882 33
nixnax 136:28a838086979 34 // Special pages when PPP-Blinky is running
nixnax 136:28a838086979 35 // 172.10.10.2 root page
nixnax 133:0f5b4085b6d3 36 // 172.10.10.2/x returns a number that increments every time you request a page - this is handy for testing
nixnax 136:28a838086979 37 // 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 136:28a838086979 38 // 172.10.10.2/ws a simple WebSocket demo
nixnax 136:28a838086979 39 // http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle
nixnax 128:e5958d143e9d 40
nixnax 93:9675adc36882 41 // Ok, enough talking, time to check out some code!!
nixnax 106:d14e6b597ca3 42
nixnax 81:9ede60e9a2c8 43 #include "mbed.h"
nixnax 128:e5958d143e9d 44 #include "sha1.h"
nixnax 130:45ee0d648a72 45 #include "BufferedSerial.h"
nixnax 131:134b6d0c11e9 46
nixnax 93:9675adc36882 47 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax 66:f005b9fdf4d1 48 // 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 110:baec959e1915 49 // Note - the LPC11U24 does NOT have a second serial port
nixnax 134:af9d1f8d451d 50 #define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax 0:2cf4880c312a 51
nixnax 93:9675adc36882 52 // here we define the OPTIONAL, second debug serial port for the various target boards
nixnax 93:9675adc36882 53 // insert your target board's port here if it's not in yet - if it works, please send it to me - thanks!!!
nixnax 129:b8a0b0e8cff1 54 // note - if you enable this, some packets may initially be missed which will cause some retransmits
nixnax 114:8a5d70bbc1b2 55 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 128:e5958d143e9d 56 #if defined(TARGET_LPC1768)
nixnax 117:c819ae068336 57 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 117:c819ae068336 58 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
nixnax 117:c819ae068336 59 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 117:c819ae068336 60 #elif defined(TARGET_LPC11U24)
nixnax 117:c819ae068336 61 #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 128:e5958d143e9d 62 #elif defined (TARGET_KL46Z) || (TARGET_KL25Z)
nixnax 128:e5958d143e9d 63 Serial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax 118:54d1936e3768 64 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 118:54d1936e3768 65 Serial xx(p9, p10); // insert your board's debug serial port pins here - and please send it to me if it works
nixnax 85:53e57ff1cf05 66 #else
nixnax 117:c819ae068336 67 #error Add your target board's second serial port here if you want to use debugging - or choose SERIAL_PORT_MONITOR_NO
nixnax 117:c819ae068336 68 #endif
nixnax 119:e14dd2bf0ea3 69 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we print debug messages */
nixnax 119:e14dd2bf0ea3 70 #define debugPutc(x...) xx.putc(x)
nixnax 118:54d1936e3768 71 #define debugBaudRate(x...) xx.baud(x)
nixnax 117:c819ae068336 72 #else
nixnax 119:e14dd2bf0ea3 73 // if we don't have a debug port the debug print functions do nothing
nixnax 119:e14dd2bf0ea3 74 #define debugPrintf(x...) {}
nixnax 119:e14dd2bf0ea3 75 #define debugPutc(x...) {}
nixnax 118:54d1936e3768 76 #define debugBaudRate(x...) {}
nixnax 41:e58a5a09f411 77 #endif
nixnax 41:e58a5a09f411 78
nixnax 110:baec959e1915 79 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 112:30172f36bd33 80 #define v0 1
nixnax 124:18ef53f1d8b7 81 #define v1 0
nixnax 77:abf92baebb42 82 #define v2 0
nixnax 114:8a5d70bbc1b2 83 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 114:8a5d70bbc1b2 84 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 29:30de79d658f6 85
nixnax 93:9675adc36882 86 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 93:9675adc36882 87 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 133:0f5b4085b6d3 88
nixnax 93:9675adc36882 89 const static char rootWebPage[] = "\
nixnax 66:f005b9fdf4d1 90 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 91 <html>\
nixnax 66:f005b9fdf4d1 92 <head>\
nixnax 128:e5958d143e9d 93 <title>mbed PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 94 <script>\
nixnax 66:f005b9fdf4d1 95 window.onload=function(){\
nixnax 66:f005b9fdf4d1 96 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 128:e5958d143e9d 97 x().textContent=parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 98 </script>\
nixnax 66:f005b9fdf4d1 99 </head>\
nixnax 139:1f87c6bc8db3 100 <body style=\"font-family: sans-serif; font-size:20px; text-align:center; color:#807070\">\
nixnax 66:f005b9fdf4d1 101 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 139:1f87c6bc8db3 102 <h1 id=\"w\">0</h1>\
nixnax 66:f005b9fdf4d1 103 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 135:6c3eec2fa634 104 <h1><a href=\"/ws\">WebSocket Demo</a></h1>\
nixnax 135:6c3eec2fa634 105 <h1><a href=\"/x\">Benchmark 1</a></h1>\
nixnax 135:6c3eec2fa634 106 <h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax 136:28a838086979 107 <h1><a href=\"http://jsfiddle.net/d26cyuh2/\">JSFiddle Demo</a></h1>\
nixnax 66:f005b9fdf4d1 108 </body>\
nixnax 139:1f87c6bc8db3 109 </html>"; // size = 634 bytes plus 1 null byte = 635 bytes
nixnax 133:0f5b4085b6d3 110
nixnax 133:0f5b4085b6d3 111 const static char webSocketPage[] = "\
nixnax 133:0f5b4085b6d3 112 <!DOCTYPE html>\
nixnax 133:0f5b4085b6d3 113 <html>\
nixnax 133:0f5b4085b6d3 114 <head>\
nixnax 133:0f5b4085b6d3 115 <title>mbed PPP-Blinky</title>\
nixnax 133:0f5b4085b6d3 116 <script>\
nixnax 133:0f5b4085b6d3 117 window.onload=function(){\
nixnax 133:0f5b4085b6d3 118 var url=\"ws://172.10.10.2\";\
nixnax 133:0f5b4085b6d3 119 var sts=document.getElementById(\"sts\");\
nixnax 133:0f5b4085b6d3 120 var btn=document.getElementById(\"btn\");\
nixnax 133:0f5b4085b6d3 121 var ctr=0;\
nixnax 133:0f5b4085b6d3 122 function show(text){sts.textContent=text;}\
nixnax 133:0f5b4085b6d3 123 btn.onclick=function(){\
nixnax 133:0f5b4085b6d3 124 if(btn.textContent==\"Connect\"){\
nixnax 133:0f5b4085b6d3 125 x=new WebSocket(url);\
nixnax 133:0f5b4085b6d3 126 x.onopen=function(){\
nixnax 133:0f5b4085b6d3 127 show(\"Connected to : \"+url);\
nixnax 133:0f5b4085b6d3 128 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 133:0f5b4085b6d3 129 };\
nixnax 133:0f5b4085b6d3 130 x.onclose=function(){show(\"closed\");};\
nixnax 133:0f5b4085b6d3 131 x.onmessage=function(msg){show(\"PPP-Blinky Sent: \\\"\"+msg.data+\"\\\"\");};\
nixnax 133:0f5b4085b6d3 132 } else {\
nixnax 133:0f5b4085b6d3 133 x.send(ctr);\
nixnax 133:0f5b4085b6d3 134 ctr=ctr+1;\
nixnax 133:0f5b4085b6d3 135 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 133:0f5b4085b6d3 136 }\
nixnax 133:0f5b4085b6d3 137 };\
nixnax 133:0f5b4085b6d3 138 };\
nixnax 133:0f5b4085b6d3 139 </script>\
nixnax 135:6c3eec2fa634 140 <body style=\"font-family: sans-serif; font-size:25px; color:#807070\">\
nixnax 135:6c3eec2fa634 141 <h1>PPP-Blinky WebSocket Test</h1>\
nixnax 133:0f5b4085b6d3 142 <div id=\"sts\">Idle</div>\
nixnax 133:0f5b4085b6d3 143 <button id=\"btn\" style=\"font-size: 100%; margin-top: 55px; margin-bottom: 55px;\">Connect</button>\
nixnax 133:0f5b4085b6d3 144 <h4><a href=\"/\">PPP-Blinky home</a></h4>\
nixnax 133:0f5b4085b6d3 145 </body>\
nixnax 136:28a838086979 146 </html>"; // size = 916 bytes + 1 null byte = 917 bytes
nixnax 69:23f560087c16 147
nixnax 73:2f56ec87dbe9 148 // 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 149 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 72:ad3d12753acf 150 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 151 // See instructions at the top.
nixnax 73:2f56ec87dbe9 152 // 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 132:09b66cc5cf4a 153 BufferedSerial pc(USBTX, USBRX, 100); // usb virtual com port for mbed hardware
nixnax 29:30de79d658f6 154
nixnax 29:30de79d658f6 155 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 156
nixnax 66:f005b9fdf4d1 157 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 158 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 159
nixnax 29:30de79d658f6 160 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 161 struct pppType {
nixnax 38:ab582987926e 162 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 163 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 164 int ledState; // state of LED1
nixnax 98:3babad0d1bd4 165 int httpPageCount;
nixnax 119:e14dd2bf0ea3 166 int firstFrame; // cleared after first frame
nixnax 4:a469050d5b80 167 struct {
nixnax 126:4e1058fa2128 168 #define RXBUFLEN (1<<11)
nixnax 117:c819ae068336 169 // the serial port receive buffer and packet buffer, size is RXBUFLEN (currently 2048 bytes)
nixnax 85:53e57ff1cf05 170 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in ring buffer
nixnax 93:9675adc36882 171 int head;
nixnax 93:9675adc36882 172 int tail;
nixnax 95:40af49390daf 173 int rtail;
nixnax 93:9675adc36882 174 int buflevel;
nixnax 38:ab582987926e 175 } rx; // serial port objects
nixnax 4:a469050d5b80 176 struct {
nixnax 38:ab582987926e 177 int len; // number of bytes in buffer
nixnax 38:ab582987926e 178 int crc; // PPP CRC (frame check)
nixnax 122:963abcbff21e 179 #define PPP_max_size 2500
nixnax 123:fc64fc6caae0 180 // we are assuming 1000 bytes more than MTU size of 1500 - due to the PPP encoding of special bytes
nixnax 122:963abcbff21e 181 char buf[PPP_max_size]; // send and receive buffer large enough for raw, encoded PPP/HDLC frames
nixnax 38:ab582987926e 182 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 183 struct {
nixnax 50:ad4e7c3c88e5 184 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 185 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 186 } hdlc; // hdlc frame objects
nixnax 114:8a5d70bbc1b2 187 struct {
nixnax 114:8a5d70bbc1b2 188 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 114:8a5d70bbc1b2 189 } ip; // ip related object
nixnax 29:30de79d658f6 190 };
nixnax 31:e000c1b9c565 191
nixnax 29:30de79d658f6 192 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 193
nixnax 93:9675adc36882 194 // Initialize our global structure, clear the buffer, etc.
nixnax 29:30de79d658f6 195 void pppInitStruct()
nixnax 29:30de79d658f6 196 {
nixnax 81:9ede60e9a2c8 197 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 29:30de79d658f6 198 ppp.online=0;
nixnax 29:30de79d658f6 199 ppp.rx.tail=0;
nixnax 93:9675adc36882 200 ppp.rx.rtail=0;
nixnax 29:30de79d658f6 201 ppp.rx.head=0;
nixnax 81:9ede60e9a2c8 202 ppp.rx.buflevel=0;
nixnax 29:30de79d658f6 203 ppp.pkt.len=0;
nixnax 114:8a5d70bbc1b2 204 ppp.ip.ident=10000; // easy to recognize in ip packet dumps
nixnax 29:30de79d658f6 205 ppp.ledState=0;
nixnax 81:9ede60e9a2c8 206 ppp.hdlc.frameStartIndex=0;
nixnax 98:3babad0d1bd4 207 ppp.httpPageCount=0;
nixnax 119:e14dd2bf0ea3 208 ppp.firstFrame=1;
nixnax 29:30de79d658f6 209 }
nixnax 26:11f4eb2663a7 210
nixnax 43:aa57db08995d 211 void led1Toggle()
nixnax 43:aa57db08995d 212 {
nixnax 140:f526e9ecfebb 213 led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax 140:f526e9ecfebb 214 ppp.ledState++;
nixnax 140:f526e9ecfebb 215
nixnax 43:aa57db08995d 216 }
nixnax 43:aa57db08995d 217
nixnax 85:53e57ff1cf05 218 // fill our own receive buffer with characters from the PPP serial port
nixnax 85:53e57ff1cf05 219 void fillbuf()
nixnax 0:2cf4880c312a 220 {
nixnax 107:5fe806713d49 221 char ch;
nixnax 85:53e57ff1cf05 222 if ( pc.readable() ) {
nixnax 85:53e57ff1cf05 223 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 93:9675adc36882 224 if ( hd == ppp.rx.rtail ) {
nixnax 119:e14dd2bf0ea3 225 debugPrintf("\nReceive buffer full\n");
nixnax 85:53e57ff1cf05 226 return;
nixnax 83:cdcb81d1910f 227 }
nixnax 107:5fe806713d49 228 ch = pc.getc(); // read new character
nixnax 107:5fe806713d49 229 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 107:5fe806713d49 230 if ( ppp.online == 0 ) {
nixnax 107:5fe806713d49 231 if (ch == 0x7E) {
nixnax 107:5fe806713d49 232 ppp.online = 1;
nixnax 114:8a5d70bbc1b2 233 }
nixnax 114:8a5d70bbc1b2 234 }
nixnax 20:5db9b77b38a6 235 ppp.rx.head = hd; // update head pointer
nixnax 81:9ede60e9a2c8 236 ppp.rx.buflevel++;
nixnax 15:b0154c910143 237 }
nixnax 0:2cf4880c312a 238 }
nixnax 0:2cf4880c312a 239
nixnax 118:54d1936e3768 240 // print to debug port while checking for incoming characters
nixnax 119:e14dd2bf0ea3 241 void putcWhileCheckingInput( char outByte )
nixnax 119:e14dd2bf0ea3 242 {
nixnax 119:e14dd2bf0ea3 243 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 119:e14dd2bf0ea3 244 fillbuf();
nixnax 119:e14dd2bf0ea3 245 debugPutc( outByte );
nixnax 119:e14dd2bf0ea3 246 fillbuf();
nixnax 119:e14dd2bf0ea3 247 #endif
nixnax 119:e14dd2bf0ea3 248 }
nixnax 119:e14dd2bf0ea3 249
nixnax 125:ea88200b1df6 250 void putsWhileCheckingInput( char * data )
nixnax 118:54d1936e3768 251 {
nixnax 118:54d1936e3768 252 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 118:54d1936e3768 253 char * nextChar = data;
nixnax 118:54d1936e3768 254 while( *nextChar != 0 ) {
nixnax 119:e14dd2bf0ea3 255 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 118:54d1936e3768 256 nextChar++;
nixnax 128:e5958d143e9d 257 }
nixnax 118:54d1936e3768 258 #endif
nixnax 118:54d1936e3768 259 }
nixnax 118:54d1936e3768 260
nixnax 124:18ef53f1d8b7 261 // a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 124:18ef53f1d8b7 262 void qq()
nixnax 124:18ef53f1d8b7 263 {
nixnax 125:ea88200b1df6 264 if ( pc.readable() ) putsWhileCheckingInput( "Character available!\n" );
nixnax 124:18ef53f1d8b7 265 }
nixnax 124:18ef53f1d8b7 266
nixnax 118:54d1936e3768 267 void crcReset()
nixnax 118:54d1936e3768 268 {
nixnax 118:54d1936e3768 269 ppp.crc=0xffff; // crc restart
nixnax 118:54d1936e3768 270 }
nixnax 118:54d1936e3768 271
nixnax 118:54d1936e3768 272 void crcDo(int x) // cumulative crc
nixnax 118:54d1936e3768 273 {
nixnax 118:54d1936e3768 274 for (int i=0; i<8; i++) {
nixnax 118:54d1936e3768 275 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 118:54d1936e3768 276 x>>=1;
nixnax 118:54d1936e3768 277 }
nixnax 124:18ef53f1d8b7 278 fillbuf(); // handle input
nixnax 118:54d1936e3768 279 }
nixnax 118:54d1936e3768 280
nixnax 118:54d1936e3768 281 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 118:54d1936e3768 282 {
nixnax 118:54d1936e3768 283 crcReset();
nixnax 118:54d1936e3768 284 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 118:54d1936e3768 285 return ppp.crc;
nixnax 118:54d1936e3768 286 }
nixnax 118:54d1936e3768 287
nixnax 85:53e57ff1cf05 288 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 289 {
nixnax 63:9253b0e1b7d8 290 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 81:9ede60e9a2c8 291 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 81:9ede60e9a2c8 292 ppp.rx.buflevel--;
nixnax 63:9253b0e1b7d8 293 return x;
nixnax 0:2cf4880c312a 294 }
nixnax 0:2cf4880c312a 295
nixnax 95:40af49390daf 296 // Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 95:40af49390daf 297 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 95:40af49390daf 298 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 95:40af49390daf 299 void dumpPPPFrame()
nixnax 95:40af49390daf 300 {
nixnax 120:bef89e4c906e 301 char pbuf[30];
nixnax 120:bef89e4c906e 302 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 124:18ef53f1d8b7 303 fillbuf();
nixnax 124:18ef53f1d8b7 304 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 124:18ef53f1d8b7 305 fillbuf();
nixnax 125:ea88200b1df6 306 putsWhileCheckingInput(pbuf);
nixnax 124:18ef53f1d8b7 307 }
nixnax 124:18ef53f1d8b7 308 fillbuf();
nixnax 124:18ef53f1d8b7 309 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 124:18ef53f1d8b7 310 fillbuf();
nixnax 125:ea88200b1df6 311 putsWhileCheckingInput(pbuf);
nixnax 95:40af49390daf 312 }
nixnax 95:40af49390daf 313
nixnax 119:e14dd2bf0ea3 314 void processPPPFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 315 {
nixnax 38:ab582987926e 316 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 317 if(start==end) {
nixnax 111:6a3b77c065c0 318 return; // empty frame
nixnax 29:30de79d658f6 319 }
nixnax 9:0992486d4a30 320 crcReset();
nixnax 9:0992486d4a30 321 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 322 ppp.pkt.len=0;
nixnax 9:0992486d4a30 323 int unstuff=0;
nixnax 17:4918c893d802 324 int idx = start;
nixnax 17:4918c893d802 325 while(1) {
nixnax 124:18ef53f1d8b7 326 fillbuf();
nixnax 9:0992486d4a30 327 if (unstuff==0) {
nixnax 72:ad3d12753acf 328 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 329 else {
nixnax 72:ad3d12753acf 330 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 331 ppp.pkt.len++;
nixnax 29:30de79d658f6 332 dest++;
nixnax 72:ad3d12753acf 333 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 334 }
nixnax 66:f005b9fdf4d1 335 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 336 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 337 ppp.pkt.len++;
nixnax 29:30de79d658f6 338 dest++;
nixnax 72:ad3d12753acf 339 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 340 unstuff=0;
nixnax 9:0992486d4a30 341 }
nixnax 81:9ede60e9a2c8 342 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 343 if (idx == end) break;
nixnax 9:0992486d4a30 344 }
nixnax 29:30de79d658f6 345 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 120:bef89e4c906e 346 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 9:0992486d4a30 347 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 348 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 349 determinePacketType();
nixnax 90:55e0f243a7ce 350 } else {
nixnax 130:45ee0d648a72 351 #define REPORT_FCS_ERROR_YES
nixnax 128:e5958d143e9d 352 #ifdef REPORT_FCS_ERROR_YES
nixnax 128:e5958d143e9d 353 char pbuf[50]; // local print buffer
nixnax 128:e5958d143e9d 354 fillbuf();
nixnax 128:e5958d143e9d 355 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 128:e5958d143e9d 356 fillbuf();
nixnax 128:e5958d143e9d 357 putsWhileCheckingInput( pbuf );
nixnax 128:e5958d143e9d 358 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 128:e5958d143e9d 359 #endif
nixnax 9:0992486d4a30 360 }
nixnax 9:0992486d4a30 361 }
nixnax 9:0992486d4a30 362
nixnax 124:18ef53f1d8b7 363 void pcPutcWhileCheckingInput(int ch)
nixnax 124:18ef53f1d8b7 364 {
nixnax 124:18ef53f1d8b7 365 fillbuf(); // check input
nixnax 124:18ef53f1d8b7 366 pc.putc(ch);
nixnax 124:18ef53f1d8b7 367 fillbuf();
nixnax 124:18ef53f1d8b7 368 }
nixnax 124:18ef53f1d8b7 369
nixnax 29:30de79d658f6 370 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 371 {
nixnax 29:30de79d658f6 372 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 124:18ef53f1d8b7 373 pcPutcWhileCheckingInput(0x7d);
nixnax 124:18ef53f1d8b7 374 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 375 } else {
nixnax 124:18ef53f1d8b7 376 pcPutcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 377 }
nixnax 11:f58998c24f0b 378 }
nixnax 9:0992486d4a30 379
nixnax 93:9675adc36882 380 void send_pppFrame() // send a PPP frame in HDLC format
nixnax 133:0f5b4085b6d3 381 {
nixnax 17:4918c893d802 382 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 383 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 384 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 124:18ef53f1d8b7 385 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 95:40af49390daf 386 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 133:0f5b4085b6d3 387 wait_us(86); // wait one character time
nixnax 133:0f5b4085b6d3 388 fillbuf();
nixnax 93:9675adc36882 389 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 93:9675adc36882 390 }
nixnax 124:18ef53f1d8b7 391 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 392 }
nixnax 9:0992486d4a30 393
nixnax 93:9675adc36882 394 void ipcpConfigRequestHandler()
nixnax 29:30de79d658f6 395 {
nixnax 119:e14dd2bf0ea3 396 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 92:cb962b365cce 397 ppp.pkt.buf[4]=2; // change code to ack
nixnax 108:f77ec4605945 398 send_pppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 106:d14e6b597ca3 399
nixnax 119:e14dd2bf0ea3 400 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 92:cb962b365cce 401 ppp.pkt.buf[4]=1; // change code to request
nixnax 106:d14e6b597ca3 402 ppp.pkt.buf[7]=4; // no options in this request
nixnax 106:d14e6b597ca3 403 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 128:e5958d143e9d 404 send_pppFrame(); // send our request
nixnax 9:0992486d4a30 405 }
nixnax 9:0992486d4a30 406
nixnax 93:9675adc36882 407 void ipcpAckHandler()
nixnax 29:30de79d658f6 408 {
nixnax 119:e14dd2bf0ea3 409 debugPrintf("Their IPCP Grant\n");
nixnax 29:30de79d658f6 410 }
nixnax 9:0992486d4a30 411
nixnax 93:9675adc36882 412 void ipcpNackHandler()
nixnax 29:30de79d658f6 413 {
nixnax 119:e14dd2bf0ea3 414 debugPrintf("Their IPCP Nack, Our ACK\n");
nixnax 107:5fe806713d49 415 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 106:d14e6b597ca3 416 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 106:d14e6b597ca3 417 send_pppFrame(); // let's request this IP address as ours
nixnax 106:d14e6b597ca3 418 } // if it's not an IP nack we ignore it
nixnax 29:30de79d658f6 419 }
nixnax 9:0992486d4a30 420
nixnax 93:9675adc36882 421 void ipcpDefaultHandler()
nixnax 29:30de79d658f6 422 {
nixnax 119:e14dd2bf0ea3 423 debugPrintf("Their IPCP Other\n");
nixnax 29:30de79d658f6 424 }
nixnax 29:30de79d658f6 425
nixnax 29:30de79d658f6 426 void IPCPframe()
nixnax 29:30de79d658f6 427 {
nixnax 9:0992486d4a30 428 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 429 switch (code) {
nixnax 29:30de79d658f6 430 case 1:
nixnax 93:9675adc36882 431 ipcpConfigRequestHandler();
nixnax 29:30de79d658f6 432 break;
nixnax 29:30de79d658f6 433 case 2:
nixnax 93:9675adc36882 434 ipcpAckHandler();
nixnax 29:30de79d658f6 435 break;
nixnax 29:30de79d658f6 436 case 3:
nixnax 93:9675adc36882 437 ipcpNackHandler();
nixnax 29:30de79d658f6 438 break;
nixnax 29:30de79d658f6 439 default:
nixnax 93:9675adc36882 440 ipcpDefaultHandler();
nixnax 9:0992486d4a30 441 }
nixnax 29:30de79d658f6 442 }
nixnax 9:0992486d4a30 443
nixnax 29:30de79d658f6 444 void UDPpacket()
nixnax 29:30de79d658f6 445 {
nixnax 12:db0dc91f0231 446 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 447 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 448 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 118:54d1936e3768 449 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 450 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 451 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 452 #endif
nixnax 12:db0dc91f0231 453 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 454 char * udpInf = udpBlock+8; // actual start of info
nixnax 118:54d1936e3768 455 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 456 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 457 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 458 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 459 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 460 #endif
nixnax 29:30de79d658f6 461 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 462 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 119:e14dd2bf0ea3 463 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 119:e14dd2bf0ea3 464 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 119:e14dd2bf0ea3 465 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 29:30de79d658f6 466 int printSize = udpLength;
nixnax 29:30de79d658f6 467 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 468 if (v1) {
nixnax 29:30de79d658f6 469 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 470 char ch = udpInf[i];
nixnax 29:30de79d658f6 471 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 472 debugPrintf("%c", ch);
nixnax 29:30de79d658f6 473 } else {
nixnax 119:e14dd2bf0ea3 474 debugPrintf("_");
nixnax 29:30de79d658f6 475 }
nixnax 29:30de79d658f6 476 }
nixnax 29:30de79d658f6 477 }
nixnax 119:e14dd2bf0ea3 478 if (v0) debugPrintf("\n");
nixnax 12:db0dc91f0231 479 }
nixnax 11:f58998c24f0b 480
nixnax 76:00e208cceb8b 481 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 482 {
nixnax 128:e5958d143e9d 483 unsigned int i,hi,lo,sum;
nixnax 76:00e208cceb8b 484 unsigned char placeHolder;
nixnax 29:30de79d658f6 485 if (len&1) {
nixnax 128:e5958d143e9d 486 placeHolder = ptr[len];
nixnax 128:e5958d143e9d 487 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 29:30de79d658f6 488 }
nixnax 128:e5958d143e9d 489 sum=0;
nixnax 128:e5958d143e9d 490 i=0;
nixnax 128:e5958d143e9d 491 while ( i<len ) {
nixnax 124:18ef53f1d8b7 492 fillbuf();
nixnax 128:e5958d143e9d 493 hi = ptr[i++];
nixnax 128:e5958d143e9d 494 lo = ptr[i++];
nixnax 128:e5958d143e9d 495 sum = sum + ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 496 }
nixnax 29:30de79d658f6 497 if (len&1) {
nixnax 128:e5958d143e9d 498 ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax 29:30de79d658f6 499 }
nixnax 76:00e208cceb8b 500 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 501 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 502 return ~sum;
nixnax 29:30de79d658f6 503 }
nixnax 11:f58998c24f0b 504
nixnax 29:30de79d658f6 505 void headerCheckSum()
nixnax 29:30de79d658f6 506 {
nixnax 11:f58998c24f0b 507 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 508 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 509 int sum=0;
nixnax 11:f58998c24f0b 510
nixnax 29:30de79d658f6 511 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 512 int hi = *ptr;
nixnax 29:30de79d658f6 513 ptr++;
nixnax 29:30de79d658f6 514 int lo = *ptr;
nixnax 29:30de79d658f6 515 ptr++;
nixnax 11:f58998c24f0b 516 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 517 sum = sum + val;
nixnax 124:18ef53f1d8b7 518 fillbuf();
nixnax 11:f58998c24f0b 519 }
nixnax 11:f58998c24f0b 520 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 521 sum = ~sum;
nixnax 11:f58998c24f0b 522 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 523 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 524 }
nixnax 9:0992486d4a30 525
nixnax 29:30de79d658f6 526 void ICMPpacket() // internet control message protocol
nixnax 128:e5958d143e9d 527 {
nixnax 12:db0dc91f0231 528 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 529 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 530 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 531 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 532 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 533 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 534 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 535 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 536 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 537 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 538 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 539 char * dstAdr = ipPkt+16;
nixnax 124:18ef53f1d8b7 540 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 18:3e35de1bc877 541 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 542 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 125:ea88200b1df6 543 if(1) {
nixnax 124:18ef53f1d8b7 544 char pbuf[50];
nixnax 124:18ef53f1d8b7 545 fillbuf();
nixnax 124:18ef53f1d8b7 546 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 125:ea88200b1df6 547 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 548 fillbuf();
nixnax 125:ea88200b1df6 549 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 124:18ef53f1d8b7 550 fillbuf();
nixnax 125:ea88200b1df6 551 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 552 }
nixnax 128:e5958d143e9d 553 #endif
nixnax 29:30de79d658f6 554 char src[4];
nixnax 29:30de79d658f6 555 char dst[4];
nixnax 12:db0dc91f0231 556 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 557 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 558 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 559 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 560 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 561 chkSum[0]=0;
nixnax 29:30de79d658f6 562 chkSum[1]=0;
nixnax 12:db0dc91f0231 563 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 564 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 565 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 566 icmpSum[0]=0;
nixnax 29:30de79d658f6 567 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 568 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 569 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 570 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 571 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 572
nixnax 16:cb0b80c24ba2 573 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 574 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 575 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 124:18ef53f1d8b7 576 if (0) {
nixnax 29:30de79d658f6 577 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 578 char ch = icmpData[i];
nixnax 29:30de79d658f6 579 if (ch>31 && ch<127) {
nixnax 124:18ef53f1d8b7 580 putcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 581 } else {
nixnax 124:18ef53f1d8b7 582 putcWhileCheckingInput('_');
nixnax 29:30de79d658f6 583 }
nixnax 29:30de79d658f6 584 }
nixnax 124:18ef53f1d8b7 585 putcWhileCheckingInput('\n');
nixnax 29:30de79d658f6 586 }
nixnax 93:9675adc36882 587 send_pppFrame(); // reply to the ping
nixnax 12:db0dc91f0231 588 } else {
nixnax 29:30de79d658f6 589 if (v0) {
nixnax 119:e14dd2bf0ea3 590 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 591 }
nixnax 128:e5958d143e9d 592 }
nixnax 11:f58998c24f0b 593 }
nixnax 11:f58998c24f0b 594
nixnax 29:30de79d658f6 595 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 596 {
nixnax 119:e14dd2bf0ea3 597 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 598 }
nixnax 11:f58998c24f0b 599
nixnax 114:8a5d70bbc1b2 600 void dumpHeaderIP (int outGoing)
nixnax 29:30de79d658f6 601 {
nixnax 114:8a5d70bbc1b2 602 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 119:e14dd2bf0ea3 603 fillbuf(); // we are expecting the first character of the next packet
nixnax 114:8a5d70bbc1b2 604 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 114:8a5d70bbc1b2 605 char * ident = ipPkt+4; // 2 bytes
nixnax 118:54d1936e3768 606 #ifdef UNUSED_IP_VARIABLES
nixnax 114:8a5d70bbc1b2 607 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 114:8a5d70bbc1b2 608 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 114:8a5d70bbc1b2 609 char * version = ipPkt; // top 4 bits
nixnax 114:8a5d70bbc1b2 610 char * ihl = ipPkt; // bottom 4 bits
nixnax 114:8a5d70bbc1b2 611 char * dscp = ipPkt+1; // top 6 bits
nixnax 114:8a5d70bbc1b2 612 char * ecn = ipPkt+1; // lower 2 bits
nixnax 114:8a5d70bbc1b2 613 char * pktLen = ipPkt+2; // 2 bytes
nixnax 114:8a5d70bbc1b2 614 char * flags = ipPkt+6; // 2 bits
nixnax 114:8a5d70bbc1b2 615 char * ttl = ipPkt+8; // 1 byte
nixnax 114:8a5d70bbc1b2 616 char * protocol = ipPkt+9; // 1 byte
nixnax 114:8a5d70bbc1b2 617 char * headercheck= ipPkt+10; // 2 bytes
nixnax 114:8a5d70bbc1b2 618 int versionIP = (version[0]>>4)&0xf;
nixnax 114:8a5d70bbc1b2 619 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 114:8a5d70bbc1b2 620 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 114:8a5d70bbc1b2 621 int ecnIP = ecn[0]&3;
nixnax 114:8a5d70bbc1b2 622 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 114:8a5d70bbc1b2 623 int flagsIP = flags[0]>>14&3;
nixnax 114:8a5d70bbc1b2 624 int ttlIP = ttl[0];
nixnax 114:8a5d70bbc1b2 625 int protocolIP = protocol[0];
nixnax 114:8a5d70bbc1b2 626 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 627 #endif
nixnax 119:e14dd2bf0ea3 628 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 119:e14dd2bf0ea3 629 char pbuf[50]; // local print buffer
nixnax 118:54d1936e3768 630 int n=0;
nixnax 119:e14dd2bf0ea3 631 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 119:e14dd2bf0ea3 632 n=n+sprintf(pbuf+n, "%05d ",IPv4Id); // IPv4Id is a good way to correlate our dumps with net monitor or wireshark traces
nixnax 119:e14dd2bf0ea3 633 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 634 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 635 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 119:e14dd2bf0ea3 636 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 119:e14dd2bf0ea3 637 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 55:43faae812be3 638 #endif
nixnax 125:ea88200b1df6 639 putsWhileCheckingInput( pbuf );
nixnax 114:8a5d70bbc1b2 640 #ifndef TCP_HEADER_DUMP_YES
nixnax 125:ea88200b1df6 641 putsWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 114:8a5d70bbc1b2 642 #endif
nixnax 114:8a5d70bbc1b2 643 #endif
nixnax 29:30de79d658f6 644 }
nixnax 26:11f4eb2663a7 645
nixnax 114:8a5d70bbc1b2 646 void dumpHeaderTCP(int outGoing)
nixnax 29:30de79d658f6 647 {
nixnax 114:8a5d70bbc1b2 648 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 114:8a5d70bbc1b2 649 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 114:8a5d70bbc1b2 650 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 114:8a5d70bbc1b2 651 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 114:8a5d70bbc1b2 652 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 114:8a5d70bbc1b2 653 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 114:8a5d70bbc1b2 654 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 114:8a5d70bbc1b2 655 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 114:8a5d70bbc1b2 656 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 114:8a5d70bbc1b2 657 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 119:e14dd2bf0ea3 658 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 119:e14dd2bf0ea3 659 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 119:e14dd2bf0ea3 660 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 114:8a5d70bbc1b2 661 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 114:8a5d70bbc1b2 662 flagInfo[8]=0; // null terminate string
nixnax 114:8a5d70bbc1b2 663 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 114:8a5d70bbc1b2 664 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 114:8a5d70bbc1b2 665 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 114:8a5d70bbc1b2 666 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 114:8a5d70bbc1b2 667 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 114:8a5d70bbc1b2 668 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 114:8a5d70bbc1b2 669 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 114:8a5d70bbc1b2 670 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 118:54d1936e3768 671 #else
nixnax 119:e14dd2bf0ea3 672 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 119:e14dd2bf0ea3 673 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 119:e14dd2bf0ea3 674 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 119:e14dd2bf0ea3 675 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 119:e14dd2bf0ea3 676 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 124:18ef53f1d8b7 677 flagInfo[1]=0; // ' '
nixnax 119:e14dd2bf0ea3 678 flagInfo[2]=0;
nixnax 118:54d1936e3768 679 #endif
nixnax 125:ea88200b1df6 680 putsWhileCheckingInput( flagInfo );
nixnax 119:e14dd2bf0ea3 681 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 682 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 125:ea88200b1df6 683 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 119:e14dd2bf0ea3 684 #endif
nixnax 119:e14dd2bf0ea3 685 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 119:e14dd2bf0ea3 686 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 118:54d1936e3768 687 }
nixnax 114:8a5d70bbc1b2 688 #endif
nixnax 29:30de79d658f6 689 }
nixnax 29:30de79d658f6 690
nixnax 128:e5958d143e9d 691 void enc64(char * in, char * out, int len)
nixnax 128:e5958d143e9d 692 {
nixnax 128:e5958d143e9d 693 const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax 128:e5958d143e9d 694 int i,j,a,b,c;
nixnax 128:e5958d143e9d 695 i=0;
nixnax 128:e5958d143e9d 696 j=0;
nixnax 128:e5958d143e9d 697 while(1) {
nixnax 128:e5958d143e9d 698 if (i<len) {
nixnax 128:e5958d143e9d 699 a = in[i++];
nixnax 128:e5958d143e9d 700 out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax 128:e5958d143e9d 701 } else break;
nixnax 128:e5958d143e9d 702 if (i<len) {
nixnax 128:e5958d143e9d 703 b = in[i++];
nixnax 128:e5958d143e9d 704 out[j++] = lut[ ( (a << 4) & 0x30) | ( (b >> 4) & 0x0f) ];
nixnax 128:e5958d143e9d 705 out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax 128:e5958d143e9d 706 } else out[j++] = '=';
nixnax 128:e5958d143e9d 707 if (i<len) {
nixnax 128:e5958d143e9d 708 c = in[i++];
nixnax 128:e5958d143e9d 709 j--;
nixnax 128:e5958d143e9d 710 out[j++] = lut[ ( (b << 2) & 0x3c) | ( (c >> 6) & 0x03) ];
nixnax 128:e5958d143e9d 711 out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax 128:e5958d143e9d 712 } else out[j++] = '=';
nixnax 128:e5958d143e9d 713 }
nixnax 128:e5958d143e9d 714 out[j]=0;
nixnax 128:e5958d143e9d 715 }
nixnax 128:e5958d143e9d 716
nixnax 128:e5958d143e9d 717 // we end up here if we enter the following javascript in a web browser console: x = new WebSocket("ws://172.10.10.2");
nixnax 128:e5958d143e9d 718 int webSocketHandler(char * dataStart)
nixnax 128:e5958d143e9d 719 {
nixnax 128:e5958d143e9d 720 int n=0; // byte counter
nixnax 128:e5958d143e9d 721 char * key = strstr(dataStart, "Sec-WebSocket-Key: "); // search for the key in the payload
nixnax 128:e5958d143e9d 722 if (key != NULL) {
nixnax 129:b8a0b0e8cff1 723 if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax 128:e5958d143e9d 724 char challenge [70];
nixnax 128:e5958d143e9d 725 strncpy(challenge,key+19,70); // a local buffer
nixnax 128:e5958d143e9d 726 *strchr(challenge,'\r')=0; // insert null so we can use sprintf
nixnax 128:e5958d143e9d 727 strncat(challenge,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11",70); // append websocket gui code
nixnax 128:e5958d143e9d 728 char shaOutput [20]; // sha1 output
nixnax 128:e5958d143e9d 729 sha1( shaOutput, challenge, strlen(challenge));
nixnax 128:e5958d143e9d 730 char encOut[50];
nixnax 128:e5958d143e9d 731 enc64( shaOutput, encOut, 20);
nixnax 128:e5958d143e9d 732 char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax 128:e5958d143e9d 733 char * version = challenge;
nixnax 128:e5958d143e9d 734 strncpy(version, versionstring,70); // copy version string
nixnax 128:e5958d143e9d 735 *strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax 128:e5958d143e9d 736 memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax 128:e5958d143e9d 737 n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax 128:e5958d143e9d 738 n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax 128:e5958d143e9d 739 n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax 128:e5958d143e9d 740 n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax 128:e5958d143e9d 741 n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax 128:e5958d143e9d 742 n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax 128:e5958d143e9d 743 n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax 128:e5958d143e9d 744 }
nixnax 128:e5958d143e9d 745 return n; // this response should satisfy a web browser's websocket protocol request
nixnax 128:e5958d143e9d 746 }
nixnax 128:e5958d143e9d 747
nixnax 128:e5958d143e9d 748 #define TCP_FLAG_ACK (1<<4)
nixnax 128:e5958d143e9d 749 #define TCP_FLAG_SYN (1<<1)
nixnax 128:e5958d143e9d 750 #define TCP_FLAG_PSH (1<<3)
nixnax 128:e5958d143e9d 751 #define TCP_FLAG_RST (1<<2)
nixnax 128:e5958d143e9d 752 #define TCP_FLAG_FIN (1<<0)
nixnax 128:e5958d143e9d 753
nixnax 68:0b74763ae67f 754 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 755 {
nixnax 67:a63e3486bcda 756 int n=0; // number of bytes we have printed so far
nixnax 128:e5958d143e9d 757 n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax 128:e5958d143e9d 758 if (n>0) return n; // if it's a WebSocket we already have the response, so return
nixnax 128:e5958d143e9d 759
nixnax 77:abf92baebb42 760 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 761 int contentLengthStart; // index where HTML starts
nixnax 133:0f5b4085b6d3 762 int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax 85:53e57ff1cf05 763
nixnax 98:3babad0d1bd4 764 ppp.httpPageCount++; // increment the number of frames we have made
nixnax 85:53e57ff1cf05 765
nixnax 128:e5958d143e9d 766 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax 128:e5958d143e9d 767 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 133:0f5b4085b6d3 768 httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax 133:0f5b4085b6d3 769 httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax 119:e14dd2bf0ea3 770 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 128:e5958d143e9d 771 if( (httpGetRoot==0) || (httpGetx==0) ) {
nixnax 133:0f5b4085b6d3 772 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax 83:cdcb81d1910f 773 } else {
nixnax 89:2c8dd0c2a426 774 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 83:cdcb81d1910f 775 }
nixnax 83:cdcb81d1910f 776 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 777 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 778 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 779 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 780 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 781 nHeader=n; // size of HTTP header
nixnax 93:9675adc36882 782 if( httpGetRoot == 0 ) {
nixnax 83:cdcb81d1910f 783 // this is where we insert our web page into the buffer
nixnax 93:9675adc36882 784 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 133:0f5b4085b6d3 785 n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax 133:0f5b4085b6d3 786 } else if ( (httpGet5 == 'w') && (httpGet6 == 's') ) { // "ws" is a special page for websocket demo
nixnax 133:0f5b4085b6d3 787 memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax 133:0f5b4085b6d3 788 n = n + sizeof(webSocketPage)-1; // one less than size
nixnax 85:53e57ff1cf05 789 } else {
nixnax 128:e5958d143e9d 790 if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax 89:2c8dd0c2a426 791
nixnax 89:2c8dd0c2a426 792 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 89:2c8dd0c2a426 793 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 89:2c8dd0c2a426 794 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 128:e5958d143e9d 795 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax 98:3babad0d1bd4 796 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.httpPageCount); // body = the http frame count
nixnax 89:2c8dd0c2a426 797 #else
nixnax 133:0f5b4085b6d3 798 if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax 133:0f5b4085b6d3 799 n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax 133:0f5b4085b6d3 800 }
nixnax 128:e5958d143e9d 801 // /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax 133:0f5b4085b6d3 802 n=n+sprintf(n+dataStart,"%d ",ppp.httpPageCount); // not really valid html but most browsers and curl are ok with it
nixnax 89:2c8dd0c2a426 803 #endif
nixnax 89:2c8dd0c2a426 804 } else {
nixnax 89:2c8dd0c2a426 805 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 128:e5958d143e9d 806 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax 89:2c8dd0c2a426 807 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 89:2c8dd0c2a426 808 }
nixnax 83:cdcb81d1910f 809 }
nixnax 83:cdcb81d1910f 810 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 811 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 812 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 813 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 814 return n; // total byte size of our response
nixnax 67:a63e3486bcda 815 }
nixnax 67:a63e3486bcda 816
nixnax 128:e5958d143e9d 817 // this is the response if we have TCP data but it's not an HTTP GET
nixnax 98:3babad0d1bd4 818 // this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 128:e5958d143e9d 819 // this could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax 128:e5958d143e9d 820 int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax 98:3babad0d1bd4 821 {
nixnax 98:3babad0d1bd4 822 int n=0; // number of bytes we have printed so far
nixnax 128:e5958d143e9d 823 if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax 128:e5958d143e9d 824 // this is most likely a websocket push message. you get this when you enter this in your browser console: x.send("my message");
nixnax 128:e5958d143e9d 825 if (0) putsWhileCheckingInput( "Got data from websocket send()\n" );
nixnax 128:e5958d143e9d 826
nixnax 128:e5958d143e9d 827 // for now we simply echo the websocket data back to the client - the client should therefore see an onmessage event
nixnax 128:e5958d143e9d 828 // to display the echoed data in your browser, enter the following into the browser console: x.onmessage = function(msg){ console.log( msg.data ); }
nixnax 128:e5958d143e9d 829 if (1) {
nixnax 128:e5958d143e9d 830 char mask [4];
nixnax 128:e5958d143e9d 831 memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax 128:e5958d143e9d 832 int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax 128:e5958d143e9d 833 if((dataStart[1]&0x80)==0x80) // test if the mask bit is set, which means all data is xor'ed with the mask
nixnax 128:e5958d143e9d 834 for (int i=0; i<websocketMessageSize; i++) dataStart[i+6]^= mask[i%4]; // unmask each byte with one of the mask bytes
nixnax 128:e5958d143e9d 835 dataStart[1] = len-2; // add four extra bytes to the message length because we don't use mask bytes for the send
nixnax 128:e5958d143e9d 836 memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax 128:e5958d143e9d 837 n = len; // our response size remains exactly the same length as what we received
nixnax 128:e5958d143e9d 838 }
nixnax 128:e5958d143e9d 839 } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax 131:134b6d0c11e9 840 n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax 131:134b6d0c11e9 841 dataStart[1]=0; // we don't have mask bytes on
nixnax 128:e5958d143e9d 842 } else if (v1) putsWhileCheckingInput("TCP data received\n");
nixnax 98:3babad0d1bd4 843 return n; // total byte size of our response
nixnax 98:3babad0d1bd4 844 }
nixnax 98:3babad0d1bd4 845
nixnax 29:30de79d658f6 846 void tcpHandler()
nixnax 29:30de79d658f6 847 {
nixnax 87:9f5ac1fabd95 848 // IP header
nixnax 26:11f4eb2663a7 849 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 850 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 851 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 852 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 853 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 854 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 855 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 856 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 857 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 858 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 859
nixnax 87:9f5ac1fabd95 860 // TCP header
nixnax 87:9f5ac1fabd95 861 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 87:9f5ac1fabd95 862 char * srctcp = tcp + 0; // 2 bytes
nixnax 87:9f5ac1fabd95 863 char * dsttcp = tcp + 2; // 2 bytes
nixnax 87:9f5ac1fabd95 864 char * seqtcp = tcp + 4; // 4 bytes
nixnax 87:9f5ac1fabd95 865 char * acktcp = tcp + 8; // 4 bytes
nixnax 87:9f5ac1fabd95 866 char * offset = tcp + 12; // 4 bits
nixnax 87:9f5ac1fabd95 867 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 87:9f5ac1fabd95 868 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 87:9f5ac1fabd95 869 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 128:e5958d143e9d 870
nixnax 124:18ef53f1d8b7 871 if(ident) {}; // shut up unused variable reference warning
nixnax 26:11f4eb2663a7 872 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 873 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 874 int protocolIP = protocol[0];
nixnax 87:9f5ac1fabd95 875 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 876 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 87:9f5ac1fabd95 877 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 85:53e57ff1cf05 878 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 85:53e57ff1cf05 879 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 85:53e57ff1cf05 880 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 87:9f5ac1fabd95 881 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 81:9ede60e9a2c8 882
nixnax 128:e5958d143e9d 883 // first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax 87:9f5ac1fabd95 884 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 87:9f5ac1fabd95 885 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 87:9f5ac1fabd95 886 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 87:9f5ac1fabd95 887 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 888 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 889 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 890
nixnax 35:e7068df4d971 891 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 892 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 87:9f5ac1fabd95 893 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 119:e14dd2bf0ea3 894 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 119:e14dd2bf0ea3 895 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 38:ab582987926e 896
nixnax 106:d14e6b597ca3 897 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 77:abf92baebb42 898
nixnax 69:23f560087c16 899 switch ( flagsTCP ) {
nixnax 128:e5958d143e9d 900 case TCP_FLAG_ACK:
nixnax 128:e5958d143e9d 901 return;
nixnax 69:23f560087c16 902 case TCP_FLAG_SYN:
nixnax 87:9f5ac1fabd95 903 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 119:e14dd2bf0ea3 904 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 85:53e57ff1cf05 905 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 906 break;
nixnax 77:abf92baebb42 907 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 128:e5958d143e9d 908 if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax 128:e5958d143e9d 909 flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // set outgoing FIN flag to ask them to close from their side
nixnax 87:9f5ac1fabd95 910 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 98:3babad0d1bd4 911 } else {
nixnax 128:e5958d143e9d 912 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not a web request, send a packet reporting number of received bytes
nixnax 69:23f560087c16 913 }
nixnax 69:23f560087c16 914 break;
nixnax 116:1272e9f7ad70 915 case TCP_FLAG_FIN:
nixnax 116:1272e9f7ad70 916 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 98:3babad0d1bd4 917 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 117:c819ae068336 918 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 128:e5958d143e9d 919 ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 920 break;
nixnax 77:abf92baebb42 921 default:
nixnax 69:23f560087c16 922 return; // ignore remaining packets
nixnax 93:9675adc36882 923 } // switch
nixnax 77:abf92baebb42 924
nixnax 69:23f560087c16 925 // The TCP flag handling is now done
nixnax 105:45001195b325 926 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 65:23b17c43aa0f 927 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 928 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 929 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 930 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 931 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 932 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 933 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 95:40af49390daf 934
nixnax 85:53e57ff1cf05 935 acktcp[0]=ack_out>>24;
nixnax 85:53e57ff1cf05 936 acktcp[1]=ack_out>>16;
nixnax 85:53e57ff1cf05 937 acktcp[2]=ack_out>>8;
nixnax 85:53e57ff1cf05 938 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 85:53e57ff1cf05 939 seqtcp[0]=seq_out>>24;
nixnax 85:53e57ff1cf05 940 seqtcp[1]=seq_out>>16;
nixnax 85:53e57ff1cf05 941 seqtcp[2]=seq_out>>8;
nixnax 85:53e57ff1cf05 942 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 943
nixnax 93:9675adc36882 944 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 93:9675adc36882 945
nixnax 114:8a5d70bbc1b2 946 // increment our outgoing ip packet counter
nixnax 114:8a5d70bbc1b2 947 ppp.ip.ident++; // get next ident number for our packet
nixnax 93:9675adc36882 948
nixnax 106:d14e6b597ca3 949 // Now we recalculate all the header sizes
nixnax 133:0f5b4085b6d3 950 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 133:0f5b4085b6d3 951 int newPacketSize = headerSizeIP + tcpSize; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 952 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 953 pktLen[1]=newPacketSize; // ip total packet size
nixnax 133:0f5b4085b6d3 954 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 36:2a9b457f8276 955
nixnax 38:ab582987926e 956 // the header is all set up, now do the IP and TCP checksums
nixnax 61:b3c1a04efd0a 957 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 958 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 959 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 960
nixnax 64:677b9713a120 961 // 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 962 // this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax 87:9f5ac1fabd95 963 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 964 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 965 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 966 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 967 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 968 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 969 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 970
nixnax 61:b3c1a04efd0a 971 // pseudo-header built, now we can calculate TCP checksum
nixnax 29:30de79d658f6 972 checksumtcp[0]=0;
nixnax 29:30de79d658f6 973 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 974 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 975 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 976 checksumtcp[1]=pseudoHeaderSum;
nixnax 87:9f5ac1fabd95 977 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 114:8a5d70bbc1b2 978 dumpHeaderIP(1); // dump outgoing IP header
nixnax 114:8a5d70bbc1b2 979 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 137:eda0cfcf4d3c 980 for (int i=0; i<45*1000/10; i++) { // 45 ms delay before sending frame - a typical internet delay time
nixnax 119:e14dd2bf0ea3 981 fillbuf(); // catch any incoming characters
nixnax 124:18ef53f1d8b7 982 wait_us(10); // wait less than 1 character duration at 115200
nixnax 119:e14dd2bf0ea3 983 }
nixnax 93:9675adc36882 984 send_pppFrame(); // All preparation complete - send the TCP response
nixnax 133:0f5b4085b6d3 985 if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
nixnax 128:e5958d143e9d 986 memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax 29:30de79d658f6 987 }
nixnax 26:11f4eb2663a7 988
nixnax 29:30de79d658f6 989 void dumpDataTCP()
nixnax 29:30de79d658f6 990 {
nixnax 26:11f4eb2663a7 991 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 992 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 993 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 994 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 995 if (v1) {
nixnax 120:bef89e4c906e 996 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 997 fillbuf();
nixnax 120:bef89e4c906e 998 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 120:bef89e4c906e 999 fillbuf();
nixnax 125:ea88200b1df6 1000 putsWhileCheckingInput( pbuf );
nixnax 29:30de79d658f6 1001 }
nixnax 29:30de79d658f6 1002 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 1003 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 125:ea88200b1df6 1004 putsWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP ); // print the tcp payload data
nixnax 125:ea88200b1df6 1005 putsWhileCheckingInput("\n");
nixnax 29:30de79d658f6 1006 }
nixnax 29:30de79d658f6 1007 }
nixnax 26:11f4eb2663a7 1008
nixnax 29:30de79d658f6 1009 void TCPpacket()
nixnax 128:e5958d143e9d 1010 {
nixnax 114:8a5d70bbc1b2 1011 dumpHeaderIP(0); // dump incoming packet header
nixnax 114:8a5d70bbc1b2 1012 dumpHeaderTCP(0); // dump incoming packet header
nixnax 128:e5958d143e9d 1013 if (v2) dumpDataTCP();
nixnax 26:11f4eb2663a7 1014 tcpHandler();
nixnax 11:f58998c24f0b 1015 }
nixnax 11:f58998c24f0b 1016
nixnax 29:30de79d658f6 1017 void otherProtocol()
nixnax 29:30de79d658f6 1018 {
nixnax 119:e14dd2bf0ea3 1019 debugPrintf("Other IP protocol");
nixnax 29:30de79d658f6 1020 }
nixnax 26:11f4eb2663a7 1021
nixnax 29:30de79d658f6 1022 void IPframe()
nixnax 29:30de79d658f6 1023 {
nixnax 10:74f8233f72c0 1024 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 1025 switch (protocol) {
nixnax 29:30de79d658f6 1026 case 1:
nixnax 29:30de79d658f6 1027 ICMPpacket();
nixnax 29:30de79d658f6 1028 break;
nixnax 29:30de79d658f6 1029 case 2:
nixnax 29:30de79d658f6 1030 IGMPpacket();
nixnax 29:30de79d658f6 1031 break;
nixnax 29:30de79d658f6 1032 case 17:
nixnax 29:30de79d658f6 1033 UDPpacket();
nixnax 29:30de79d658f6 1034 break;
nixnax 29:30de79d658f6 1035 case 6:
nixnax 29:30de79d658f6 1036 TCPpacket();
nixnax 29:30de79d658f6 1037 break;
nixnax 29:30de79d658f6 1038 default:
nixnax 29:30de79d658f6 1039 otherProtocol();
nixnax 29:30de79d658f6 1040 }
nixnax 29:30de79d658f6 1041 }
nixnax 9:0992486d4a30 1042
nixnax 29:30de79d658f6 1043 void LCPconfReq()
nixnax 29:30de79d658f6 1044 {
nixnax 119:e14dd2bf0ea3 1045 debugPrintf("LCP Config ");
nixnax 9:0992486d4a30 1046 if (ppp.pkt.buf[7] != 4) {
nixnax 111:6a3b77c065c0 1047 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 119:e14dd2bf0ea3 1048 debugPrintf("Reject\n");
nixnax 93:9675adc36882 1049 send_pppFrame();
nixnax 9:0992486d4a30 1050 } else {
nixnax 9:0992486d4a30 1051 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 119:e14dd2bf0ea3 1052 debugPrintf("Ack\n");
nixnax 93:9675adc36882 1053 send_pppFrame();
nixnax 119:e14dd2bf0ea3 1054 debugPrintf("LCP Ask\n");
nixnax 11:f58998c24f0b 1055 ppp.pkt.buf[4]=1; // request no options
nixnax 93:9675adc36882 1056 send_pppFrame();
nixnax 9:0992486d4a30 1057 }
nixnax 9:0992486d4a30 1058 }
nixnax 9:0992486d4a30 1059
nixnax 29:30de79d658f6 1060 void LCPconfAck()
nixnax 29:30de79d658f6 1061 {
nixnax 119:e14dd2bf0ea3 1062 debugPrintf("LCP Ack\n");
nixnax 29:30de79d658f6 1063 }
nixnax 9:0992486d4a30 1064
nixnax 29:30de79d658f6 1065 void LCPend()
nixnax 29:30de79d658f6 1066 {
nixnax 29:30de79d658f6 1067 ppp.pkt.buf[4]=6;
nixnax 93:9675adc36882 1068 send_pppFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 1069 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 1070 pppInitStruct(); // flush the receive buffer
nixnax 119:e14dd2bf0ea3 1071 debugPrintf("LCP End\n");
nixnax 9:0992486d4a30 1072 }
nixnax 9:0992486d4a30 1073
nixnax 29:30de79d658f6 1074 void LCPother()
nixnax 29:30de79d658f6 1075 {
nixnax 119:e14dd2bf0ea3 1076 debugPrintf("LCP Other\n");
nixnax 95:40af49390daf 1077 dumpPPPFrame();
nixnax 29:30de79d658f6 1078 }
nixnax 29:30de79d658f6 1079
nixnax 29:30de79d658f6 1080 void LCPframe()
nixnax 29:30de79d658f6 1081 {
nixnax 29:30de79d658f6 1082 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 1083 switch (code) {
nixnax 29:30de79d658f6 1084 case 1:
nixnax 29:30de79d658f6 1085 LCPconfReq();
nixnax 29:30de79d658f6 1086 break; // config request
nixnax 29:30de79d658f6 1087 case 2:
nixnax 29:30de79d658f6 1088 LCPconfAck();
nixnax 29:30de79d658f6 1089 break; // config ack
nixnax 29:30de79d658f6 1090 case 5:
nixnax 29:30de79d658f6 1091 LCPend();
nixnax 29:30de79d658f6 1092 break; // end connection
nixnax 29:30de79d658f6 1093 default:
nixnax 29:30de79d658f6 1094 LCPother();
nixnax 29:30de79d658f6 1095 }
nixnax 9:0992486d4a30 1096 }
nixnax 9:0992486d4a30 1097
nixnax 29:30de79d658f6 1098 void discardedFrame()
nixnax 29:30de79d658f6 1099 {
nixnax 128:e5958d143e9d 1100 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 9:0992486d4a30 1101 }
nixnax 9:0992486d4a30 1102
nixnax 29:30de79d658f6 1103 void determinePacketType()
nixnax 29:30de79d658f6 1104 {
nixnax 29:30de79d658f6 1105 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 119:e14dd2bf0ea3 1106 debugPrintf("byte0 != ff\n");
nixnax 29:30de79d658f6 1107 return;
nixnax 29:30de79d658f6 1108 }
nixnax 29:30de79d658f6 1109 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 119:e14dd2bf0ea3 1110 debugPrintf("byte1 != 3\n");
nixnax 29:30de79d658f6 1111 return;
nixnax 29:30de79d658f6 1112 }
nixnax 29:30de79d658f6 1113 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 119:e14dd2bf0ea3 1114 debugPrintf("byte2 != 21\n");
nixnax 29:30de79d658f6 1115 return;
nixnax 29:30de79d658f6 1116 }
nixnax 9:0992486d4a30 1117 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 1118 switch (packetType) {
nixnax 29:30de79d658f6 1119 case 0xc0:
nixnax 29:30de79d658f6 1120 LCPframe();
nixnax 29:30de79d658f6 1121 break; // link control
nixnax 29:30de79d658f6 1122 case 0x80:
nixnax 29:30de79d658f6 1123 IPCPframe();
nixnax 29:30de79d658f6 1124 break; // IP control
nixnax 29:30de79d658f6 1125 case 0x00:
nixnax 29:30de79d658f6 1126 IPframe();
nixnax 29:30de79d658f6 1127 break; // IP itself
nixnax 29:30de79d658f6 1128 default:
nixnax 29:30de79d658f6 1129 discardedFrame();
nixnax 9:0992486d4a30 1130 }
nixnax 29:30de79d658f6 1131 }
nixnax 9:0992486d4a30 1132
nixnax 128:e5958d143e9d 1133 void wait_for_PPP_frame() // scan the PPP serial input stream for frame start markers
nixnax 50:ad4e7c3c88e5 1134 {
nixnax 85:53e57ff1cf05 1135 while(1) {
nixnax 93:9675adc36882 1136 fillbuf(); // handle received characters
nixnax 124:18ef53f1d8b7 1137 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 81:9ede60e9a2c8 1138 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 1139 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 1140 if (rx==FRAME_7E) {
nixnax 120:bef89e4c906e 1141 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 119:e14dd2bf0ea3 1142 ppp.firstFrame=0;
nixnax 128:e5958d143e9d 1143 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 120:bef89e4c906e 1144 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 119:e14dd2bf0ea3 1145 } else {
nixnax 119:e14dd2bf0ea3 1146 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 119:e14dd2bf0ea3 1147 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 128:e5958d143e9d 1148 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 128:e5958d143e9d 1149 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax 119:e14dd2bf0ea3 1150 break;
nixnax 119:e14dd2bf0ea3 1151 }
nixnax 50:ad4e7c3c88e5 1152 }
nixnax 50:ad4e7c3c88e5 1153 }
nixnax 85:53e57ff1cf05 1154 }
nixnax 50:ad4e7c3c88e5 1155 }
nixnax 50:ad4e7c3c88e5 1156
nixnax 29:30de79d658f6 1157 void scanForConnectString()
nixnax 29:30de79d658f6 1158 {
nixnax 81:9ede60e9a2c8 1159 while(ppp.online == 0) {
nixnax 114:8a5d70bbc1b2 1160 fillbuf(); // gather received characters
nixnax 81:9ede60e9a2c8 1161 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 106:d14e6b597ca3 1162 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 107:5fe806713d49 1163 if (found1 != NULL) {
nixnax 107:5fe806713d49 1164 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 119:e14dd2bf0ea3 1165 if (v0) debugPrintf("Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 107:5fe806713d49 1166 pc.puts("CLIENTSERVER");
nixnax 120:bef89e4c906e 1167 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 119:e14dd2bf0ea3 1168 fillbuf();
nixnax 9:0992486d4a30 1169 }
nixnax 9:0992486d4a30 1170 }
nixnax 103:4f5512dd11cf 1171 }
nixnax 81:9ede60e9a2c8 1172
nixnax 0:2cf4880c312a 1173 int main()
nixnax 0:2cf4880c312a 1174 {
nixnax 128:e5958d143e9d 1175 pc.baud(115200); // USB serial port to pc
nixnax 128:e5958d143e9d 1176 debugBaudRate(115200); // baud rate for our (optional) debug port
nixnax 128:e5958d143e9d 1177 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 136:28a838086979 1178
nixnax 9:0992486d4a30 1179 pppInitStruct(); // initialize all the PPP properties
nixnax 0:2cf4880c312a 1180 while(1) {
nixnax 128:e5958d143e9d 1181 scanForConnectString(); // wait for connect from PC dial-up networking
nixnax 81:9ede60e9a2c8 1182 while(ppp.online) {
nixnax 120:bef89e4c906e 1183 wait_for_PPP_frame(); // wait for a PPP frame
nixnax 81:9ede60e9a2c8 1184 }
nixnax 7:ab147f5e97ac 1185 }
nixnax 105:45001195b325 1186 }