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@202:f7338545522a, 2018-03-12 (annotated)

Committer:
nixnax
Date:
Mon Mar 12 03:01:42 2018 +0000
Revision:
202:f7338545522a
Parent:
201:9fcf92e9f427
Child:
205:c730866cb598
Latest mbed library - Revision 160

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 182:f039ec218c9f 1 // PPP-Blinky - "The Most Basic Internet 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 201:9fcf92e9f427 12 // Important - ensure that you are using the latest mbed firmware for your specific mbed target board
nixnax 201:9fcf92e9f427 13
nixnax 142:54d1543e23e5 14 // Handy reading material
nixnax 142:54d1543e23e5 15 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 142:54d1543e23e5 16 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 142:54d1543e23e5 17 // http://atari.kensclassics.org/wcomlog.htm
nixnax 142:54d1543e23e5 18
nixnax 142:54d1543e23e5 19 // Handy tools
nixnax 142:54d1543e23e5 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 142:54d1543e23e5 21 // https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax 142:54d1543e23e5 22 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 142:54d1543e23e5 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 142:54d1543e23e5 24 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 142:54d1543e23e5 25 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 142:54d1543e23e5 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 142:54d1543e23e5 27
nixnax 142:54d1543e23e5 28 // Connecting PPP-Blinky to Linux
nixnax 142:54d1543e23e5 29 // PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax 142:54d1543e23e5 30 // pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax 142:54d1543e23e5 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 142:54d1543e23e5 32 // See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax 142:54d1543e23e5 33
nixnax 142:54d1543e23e5 34 // Special pages when PPP-Blinky is running
nixnax 142:54d1543e23e5 35 // 172.10.10.2 root page
nixnax 182:f039ec218c9f 36 // 172.10.10.2/x returns the number of ppp frames sent - this is handy for testing
nixnax 182:f039ec218c9f 37 // 172.10.10.2/xb also returns number of ppp frames sent, but issues a fast refresh meta command. This allows you to use your browser to benchmark page load speed
nixnax 142:54d1543e23e5 38 // 172.10.10.2/ws a simple WebSocket demo
nixnax 182:f039ec218c9f 39 // http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle, showing cross-domain access
nixnax 142:54d1543e23e5 40
nixnax 142:54d1543e23e5 41 // Ok, enough talking, time to check out some code!!
nixnax 142:54d1543e23e5 42
nixnax 142:54d1543e23e5 43 #include "ppp-blinky.h"
nixnax 142:54d1543e23e5 44
nixnax 142:54d1543e23e5 45 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax 146:a45f49a2b29c 46 // Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor the debug output.
nixnax 142:54d1543e23e5 47 // Using the second serial port will slow down packet response time
nixnax 142:54d1543e23e5 48 // Note - the LPC11U24 does NOT have a second serial port
nixnax 146:a45f49a2b29c 49
nixnax 183:6d3ba874b267 50 #define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax 142:54d1543e23e5 51
nixnax 142:54d1543e23e5 52 // here we define the OPTIONAL, second debug serial port for various mbed target boards
nixnax 142:54d1543e23e5 53 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 54 #if defined(TARGET_LPC1768)
nixnax 179:ba2b2ddd0da5 55 RawSerial 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 56 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
nixnax 179:ba2b2ddd0da5 57 RawSerial 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 196:8791e241be80 58 #elif defined(TARGET_NUCLEO_L432KC)
nixnax 196:8791e241be80 59 RawSerial xx(PA_9, PA_10); // Second serial port on NUCLEO-L432KC - 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 60 #elif defined(TARGET_LPC11U24)
nixnax 142:54d1543e23e5 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 142:54d1543e23e5 62 #elif defined (TARGET_KL46Z) || (TARGET_KL25Z)
nixnax 179:ba2b2ddd0da5 63 RawSerial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax 193:48072570f41d 64 #elif defined(TARGET_KW41Z)
nixnax 194:5b23ebfb3626 65 RawSerial xx(PTC3, PTC2); // Second serial port on FRDM-KW41Z board
nixnax 142:54d1543e23e5 66 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 142:54d1543e23e5 67 // 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 179:ba2b2ddd0da5 68 RawSerial 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 69 #else
nixnax 142:54d1543e23e5 70 #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 71 #endif
nixnax 179:ba2b2ddd0da5 72 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we can print debug messages */
nixnax 142:54d1543e23e5 73 #define debugPutc(x...) xx.putc(x)
nixnax 142:54d1543e23e5 74 #define debugBaudRate(x...) xx.baud(x)
nixnax 142:54d1543e23e5 75 #else
nixnax 142:54d1543e23e5 76 // if we don't have a debug port the debug print functions do nothing
nixnax 142:54d1543e23e5 77 #define debugPrintf(x...) {}
nixnax 142:54d1543e23e5 78 #define debugPutc(x...) {}
nixnax 142:54d1543e23e5 79 #define debugBaudRate(x...) {}
nixnax 142:54d1543e23e5 80 #endif
nixnax 142:54d1543e23e5 81
nixnax 142:54d1543e23e5 82 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 182:f039ec218c9f 83 #define v0 1
nixnax 142:54d1543e23e5 84 #define v1 0
nixnax 142:54d1543e23e5 85 #define v2 0
nixnax 182:f039ec218c9f 86 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 182:f039ec218c9f 87 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 142:54d1543e23e5 88
nixnax 142:54d1543e23e5 89 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 142:54d1543e23e5 90 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 142:54d1543e23e5 91
nixnax 142:54d1543e23e5 92 const static char rootWebPage[] = "\
nixnax 142:54d1543e23e5 93 <!DOCTYPE html>\
nixnax 142:54d1543e23e5 94 <html>\
nixnax 142:54d1543e23e5 95 <head>\
nixnax 146:a45f49a2b29c 96 <title>mbed PPP-Blinky</title>\r\n\
nixnax 146:a45f49a2b29c 97 <script>\r\n\
nixnax 142:54d1543e23e5 98 window.onload=function(){\
nixnax 142:54d1543e23e5 99 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 146:a45f49a2b29c 100 x().textContent=parseInt(x().textContent)+1;},100);};\r\n\
nixnax 146:a45f49a2b29c 101 </script>\r\n\
nixnax 142:54d1543e23e5 102 </head>\
nixnax 142:54d1543e23e5 103 <body style=\"font-family: sans-serif; font-size:20px; text-align:center; color:#807070\">\
nixnax 142:54d1543e23e5 104 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 142:54d1543e23e5 105 <h1 id=\"w\">0</h1>\
nixnax 142:54d1543e23e5 106 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 142:54d1543e23e5 107 <h1><a href=\"/ws\">WebSocket Demo</a></h1>\
nixnax 142:54d1543e23e5 108 <h1><a href=\"/x\">Benchmark 1</a></h1>\
nixnax 142:54d1543e23e5 109 <h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax 142:54d1543e23e5 110 <h1><a href=\"http://jsfiddle.net/d26cyuh2/\">JSFiddle Demo</a></h1>\
nixnax 142:54d1543e23e5 111 </body>\
nixnax 146:a45f49a2b29c 112 </html>\r\n"; // size = 644 bytes plus 1 null byte = 645 bytes
nixnax 142:54d1543e23e5 113
nixnax 167:ff8a2d8beeb1 114 // this is a websocket demo html page we serve when GET /ws is requested
nixnax 142:54d1543e23e5 115 const static char webSocketPage[] = "\
nixnax 142:54d1543e23e5 116 <!DOCTYPE html>\
nixnax 142:54d1543e23e5 117 <html>\
nixnax 142:54d1543e23e5 118 <head>\
nixnax 142:54d1543e23e5 119 <title>mbed PPP-Blinky</title>\
nixnax 142:54d1543e23e5 120 <script>\
nixnax 142:54d1543e23e5 121 window.onload=function(){\
nixnax 142:54d1543e23e5 122 var url=\"ws://172.10.10.2\";\
nixnax 142:54d1543e23e5 123 var sts=document.getElementById(\"sts\");\
nixnax 142:54d1543e23e5 124 var btn=document.getElementById(\"btn\");\
nixnax 142:54d1543e23e5 125 var ctr=0;\
nixnax 142:54d1543e23e5 126 function show(text){sts.textContent=text;}\
nixnax 142:54d1543e23e5 127 btn.onclick=function(){\
nixnax 142:54d1543e23e5 128 if(btn.textContent==\"Connect\"){\
nixnax 142:54d1543e23e5 129 x=new WebSocket(url);\
nixnax 142:54d1543e23e5 130 x.onopen=function(){\
nixnax 142:54d1543e23e5 131 show(\"Connected to : \"+url);\
nixnax 142:54d1543e23e5 132 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 142:54d1543e23e5 133 };\
nixnax 142:54d1543e23e5 134 x.onclose=function(){show(\"closed\");};\
nixnax 142:54d1543e23e5 135 x.onmessage=function(msg){show(\"PPP-Blinky Sent: \\\"\"+msg.data+\"\\\"\");};\
nixnax 142:54d1543e23e5 136 } else {\
nixnax 142:54d1543e23e5 137 x.send(ctr);\
nixnax 142:54d1543e23e5 138 ctr=ctr+1;\
nixnax 142:54d1543e23e5 139 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 142:54d1543e23e5 140 }\
nixnax 142:54d1543e23e5 141 };\
nixnax 142:54d1543e23e5 142 };\
nixnax 142:54d1543e23e5 143 </script>\
nixnax 142:54d1543e23e5 144 <body style=\"font-family: sans-serif; font-size:25px; color:#807070\">\
nixnax 142:54d1543e23e5 145 <h1>PPP-Blinky WebSocket Test</h1>\
nixnax 142:54d1543e23e5 146 <div id=\"sts\">Idle</div>\
nixnax 142:54d1543e23e5 147 <button id=\"btn\" style=\"font-size: 100%; margin-top: 55px; margin-bottom: 55px;\">Connect</button>\
nixnax 142:54d1543e23e5 148 <h4><a href=\"/\">PPP-Blinky home</a></h4>\
nixnax 142:54d1543e23e5 149 </body>\
nixnax 142:54d1543e23e5 150 </html>"; // size = 916 bytes + 1 null byte = 917 bytes
nixnax 142:54d1543e23e5 151
nixnax 142:54d1543e23e5 152 // 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 153 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 142:54d1543e23e5 154 // The modem baud rate should be set to 115200 baud
nixnax 142:54d1543e23e5 155 // See instructions at the top.
nixnax 142:54d1543e23e5 156 // 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 179:ba2b2ddd0da5 157 RawSerial pc (USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax 142:54d1543e23e5 158
nixnax 142:54d1543e23e5 159 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 142:54d1543e23e5 160
nixnax 142:54d1543e23e5 161 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 142:54d1543e23e5 162 #define FRAME_7E (0x7e)
nixnax 142:54d1543e23e5 163
nixnax 142:54d1543e23e5 164 pppType ppp; // our global - definitely not thread safe
nixnax 142:54d1543e23e5 165
nixnax 142:54d1543e23e5 166 /// Initialize the ppp structure and clear the receive buffer
nixnax 142:54d1543e23e5 167 void pppInitStruct()
nixnax 142:54d1543e23e5 168 {
nixnax 142:54d1543e23e5 169 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 142:54d1543e23e5 170 ppp.online=0;
nixnax 142:54d1543e23e5 171 ppp.rx.tail=0;
nixnax 142:54d1543e23e5 172 ppp.rx.rtail=0;
nixnax 142:54d1543e23e5 173 ppp.rx.head=0;
nixnax 142:54d1543e23e5 174 ppp.rx.buflevel=0;
nixnax 142:54d1543e23e5 175 ppp.pkt.len=0;
nixnax 154:18b2bd92f557 176 ppp.ipData.ident=10000; // easy to recognize in ip packet dumps
nixnax 142:54d1543e23e5 177 ppp.ledState=0;
nixnax 142:54d1543e23e5 178 ppp.hdlc.frameStartIndex=0;
nixnax 146:a45f49a2b29c 179 ppp.responseCounter=0;
nixnax 142:54d1543e23e5 180 ppp.firstFrame=1;
nixnax 175:b4e6f8a6fe00 181 ppp.ppp = (pppHeaderType *)ppp.pkt.buf; // pointer to ppp header
nixnax 175:b4e6f8a6fe00 182 ppp.ip = (ipHeaderType *)(ppp.pkt.buf+4); // pointer to IP header
nixnax 142:54d1543e23e5 183 }
nixnax 142:54d1543e23e5 184
nixnax 142:54d1543e23e5 185 /// Toggle the LED on every second PPP packet received
nixnax 142:54d1543e23e5 186 void led1Toggle()
nixnax 142:54d1543e23e5 187 {
nixnax 142:54d1543e23e5 188 led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax 143:c5019f856a56 189 ppp.ledState++;
nixnax 142:54d1543e23e5 190 }
nixnax 142:54d1543e23e5 191
nixnax 179:ba2b2ddd0da5 192 /// Returns 1 after a connect message, 0 at startup or after a disconnect message
nixnax 150:3366bf3d294e 193 int connectedPpp()
nixnax 142:54d1543e23e5 194 {
nixnax 142:54d1543e23e5 195 return ppp.online;
nixnax 143:c5019f856a56 196 }
nixnax 142:54d1543e23e5 197
nixnax 179:ba2b2ddd0da5 198 /// Previously used to check for characters in receive buffer.
nixnax 179:ba2b2ddd0da5 199 /// Now just a stub.
nixnax 179:ba2b2ddd0da5 200 void checkPc() {};
nixnax 179:ba2b2ddd0da5 201
nixnax 179:ba2b2ddd0da5 202 /// PPP serial port receive interrupt handler.
nixnax 143:c5019f856a56 203 /// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax 143:c5019f856a56 204 /// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax 179:ba2b2ddd0da5 205 void pppReceiveHandler()
nixnax 142:54d1543e23e5 206 {
nixnax 142:54d1543e23e5 207 char ch;
nixnax 179:ba2b2ddd0da5 208 while ( pc.readable() ) {
nixnax 142:54d1543e23e5 209 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 142:54d1543e23e5 210 if ( hd == ppp.rx.rtail ) {
nixnax 142:54d1543e23e5 211 debugPrintf("\nReceive buffer full\n");
nixnax 142:54d1543e23e5 212 return;
nixnax 142:54d1543e23e5 213 }
nixnax 142:54d1543e23e5 214 ch = pc.getc(); // read new character
nixnax 142:54d1543e23e5 215 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 142:54d1543e23e5 216 if ( ppp.online == 0 ) {
nixnax 142:54d1543e23e5 217 if (ch == 0x7E) {
nixnax 142:54d1543e23e5 218 ppp.online = 1;
nixnax 142:54d1543e23e5 219 }
nixnax 142:54d1543e23e5 220 }
nixnax 142:54d1543e23e5 221 ppp.rx.head = hd; // update head pointer
nixnax 142:54d1543e23e5 222 ppp.rx.buflevel++;
nixnax 142:54d1543e23e5 223 }
nixnax 142:54d1543e23e5 224 }
nixnax 142:54d1543e23e5 225
nixnax 142:54d1543e23e5 226 /// print to debug port while checking for incoming characters
nixnax 142:54d1543e23e5 227 void putcWhileCheckingInput( char outByte )
nixnax 142:54d1543e23e5 228 {
nixnax 142:54d1543e23e5 229 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 230 checkPc();
nixnax 142:54d1543e23e5 231 debugPutc( outByte );
nixnax 142:54d1543e23e5 232 checkPc();
nixnax 142:54d1543e23e5 233 #endif
nixnax 142:54d1543e23e5 234 }
nixnax 142:54d1543e23e5 235
nixnax 142:54d1543e23e5 236 /// puts to debug port while checking the PPP input stream
nixnax 142:54d1543e23e5 237 void putsWhileCheckingInput( char * data )
nixnax 142:54d1543e23e5 238 {
nixnax 142:54d1543e23e5 239 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 240 char * nextChar = data;
nixnax 142:54d1543e23e5 241 while( *nextChar != 0 ) {
nixnax 142:54d1543e23e5 242 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 142:54d1543e23e5 243 nextChar++;
nixnax 142:54d1543e23e5 244 }
nixnax 142:54d1543e23e5 245 #endif
nixnax 142:54d1543e23e5 246 }
nixnax 142:54d1543e23e5 247
nixnax 145:098b6ed2f7f2 248 /// Initialize the PPP FCS (frame check sequence) total
nixnax 145:098b6ed2f7f2 249 void fcsReset()
nixnax 142:54d1543e23e5 250 {
nixnax 145:098b6ed2f7f2 251 ppp.fcs=0xffff; // crc restart
nixnax 142:54d1543e23e5 252 }
nixnax 142:54d1543e23e5 253
nixnax 145:098b6ed2f7f2 254 /// update the cumulative PPP FCS (frame check sequence)
nixnax 145:098b6ed2f7f2 255 void fcsDo(int x)
nixnax 142:54d1543e23e5 256 {
nixnax 142:54d1543e23e5 257 for (int i=0; i<8; i++) {
nixnax 145:098b6ed2f7f2 258 ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1; // crc calculator
nixnax 142:54d1543e23e5 259 x>>=1;
nixnax 142:54d1543e23e5 260 }
nixnax 142:54d1543e23e5 261 checkPc(); // handle input
nixnax 142:54d1543e23e5 262 }
nixnax 142:54d1543e23e5 263
nixnax 145:098b6ed2f7f2 264 /// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax 145:098b6ed2f7f2 265 int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax 142:54d1543e23e5 266 {
nixnax 145:098b6ed2f7f2 267 fcsReset();
nixnax 145:098b6ed2f7f2 268 for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax 145:098b6ed2f7f2 269 return ppp.fcs;
nixnax 142:54d1543e23e5 270 }
nixnax 142:54d1543e23e5 271
nixnax 142:54d1543e23e5 272 /// Get one character from our received PPP buffer
nixnax 142:54d1543e23e5 273 int pc_getBuf()
nixnax 142:54d1543e23e5 274 {
nixnax 142:54d1543e23e5 275 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 142:54d1543e23e5 276 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 142:54d1543e23e5 277 ppp.rx.buflevel--;
nixnax 142:54d1543e23e5 278 return x;
nixnax 142:54d1543e23e5 279 }
nixnax 142:54d1543e23e5 280
nixnax 142:54d1543e23e5 281 /// Dump a PPP frame to the debug serial port
nixnax 142:54d1543e23e5 282 /// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 142:54d1543e23e5 283 /// Capture the frame's hex output in your terminal program and save as a text file
nixnax 164:c3de3d212c4b 284 /// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax 142:54d1543e23e5 285 void dumpPPPFrame()
nixnax 142:54d1543e23e5 286 {
nixnax 142:54d1543e23e5 287 char pbuf[30];
nixnax 142:54d1543e23e5 288 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 289 checkPc();
nixnax 142:54d1543e23e5 290 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 142:54d1543e23e5 291 checkPc();
nixnax 142:54d1543e23e5 292 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 293 }
nixnax 142:54d1543e23e5 294 checkPc();
nixnax 142:54d1543e23e5 295 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 142:54d1543e23e5 296 checkPc();
nixnax 142:54d1543e23e5 297 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 298 }
nixnax 142:54d1543e23e5 299
nixnax 142:54d1543e23e5 300 /// Process a received PPP frame
nixnax 142:54d1543e23e5 301 void processPPPFrame(int start, int end)
nixnax 142:54d1543e23e5 302 {
nixnax 142:54d1543e23e5 303 led1Toggle(); // change led1 state on every frame we receive
nixnax 142:54d1543e23e5 304 if(start==end) {
nixnax 142:54d1543e23e5 305 return; // empty frame
nixnax 142:54d1543e23e5 306 }
nixnax 145:098b6ed2f7f2 307 fcsReset();
nixnax 142:54d1543e23e5 308 char * dest = ppp.pkt.buf;
nixnax 142:54d1543e23e5 309 ppp.pkt.len=0;
nixnax 142:54d1543e23e5 310 int unstuff=0;
nixnax 142:54d1543e23e5 311 int idx = start;
nixnax 142:54d1543e23e5 312 while(1) {
nixnax 142:54d1543e23e5 313 checkPc();
nixnax 142:54d1543e23e5 314 if (unstuff==0) {
nixnax 142:54d1543e23e5 315 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 142:54d1543e23e5 316 else {
nixnax 142:54d1543e23e5 317 *dest = ppp.rx.buf[idx];
nixnax 142:54d1543e23e5 318 ppp.pkt.len++;
nixnax 142:54d1543e23e5 319 dest++;
nixnax 145:098b6ed2f7f2 320 fcsDo(ppp.rx.buf[idx]);
nixnax 142:54d1543e23e5 321 }
nixnax 142:54d1543e23e5 322 } else { // unstuff characters prefixed with 0x7d
nixnax 142:54d1543e23e5 323 *dest = ppp.rx.buf[idx]^0x20;
nixnax 142:54d1543e23e5 324 ppp.pkt.len++;
nixnax 142:54d1543e23e5 325 dest++;
nixnax 145:098b6ed2f7f2 326 fcsDo(ppp.rx.buf[idx]^0x20);
nixnax 142:54d1543e23e5 327 unstuff=0;
nixnax 142:54d1543e23e5 328 }
nixnax 142:54d1543e23e5 329 idx = (idx+1) & (RXBUFLEN-1);
nixnax 142:54d1543e23e5 330 if (idx == end) break;
nixnax 142:54d1543e23e5 331 }
nixnax 145:098b6ed2f7f2 332 ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax 142:54d1543e23e5 333 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 142:54d1543e23e5 334 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 142:54d1543e23e5 335 determinePacketType();
nixnax 142:54d1543e23e5 336 } else {
nixnax 142:54d1543e23e5 337 #define REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 338 #ifdef REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 339 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 340 checkPc();
nixnax 142:54d1543e23e5 341 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 142:54d1543e23e5 342 checkPc();
nixnax 142:54d1543e23e5 343 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 344 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 142:54d1543e23e5 345 #endif
nixnax 142:54d1543e23e5 346 }
nixnax 142:54d1543e23e5 347 }
nixnax 142:54d1543e23e5 348
nixnax 142:54d1543e23e5 349 /// output a character to the PPP port while checking for incoming characters
nixnax 142:54d1543e23e5 350 void pcPutcWhileCheckingInput(int ch)
nixnax 142:54d1543e23e5 351 {
nixnax 142:54d1543e23e5 352 checkPc(); // check input
nixnax 142:54d1543e23e5 353 pc.putc(ch);
nixnax 142:54d1543e23e5 354 checkPc();
nixnax 142:54d1543e23e5 355 }
nixnax 142:54d1543e23e5 356
nixnax 142:54d1543e23e5 357 /// do PPP HDLC-like handling of special (flag) characters
nixnax 143:c5019f856a56 358 void hdlcPut(int ch)
nixnax 142:54d1543e23e5 359 {
nixnax 142:54d1543e23e5 360 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 142:54d1543e23e5 361 pcPutcWhileCheckingInput(0x7d);
nixnax 142:54d1543e23e5 362 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 142:54d1543e23e5 363 } else {
nixnax 142:54d1543e23e5 364 pcPutcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 365 }
nixnax 142:54d1543e23e5 366 }
nixnax 142:54d1543e23e5 367
nixnax 142:54d1543e23e5 368 /// send a PPP frame in HDLC format
nixnax 144:01d98cf7738e 369 void sendPppFrame()
nixnax 143:c5019f856a56 370 {
nixnax 172:449dd7a28955 371 ppp.responseCounter++; // count the number of ppp frames we send
nixnax 145:098b6ed2f7f2 372 int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 142:54d1543e23e5 373 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 142:54d1543e23e5 374 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 142:54d1543e23e5 375 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 142:54d1543e23e5 376 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 377 wait_us(86); // wait one character time
nixnax 142:54d1543e23e5 378 checkPc();
nixnax 142:54d1543e23e5 379 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 142:54d1543e23e5 380 }
nixnax 142:54d1543e23e5 381 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 142:54d1543e23e5 382 }
nixnax 142:54d1543e23e5 383
nixnax 143:c5019f856a56 384 /// convert a network ip address in the buffer to an integer (IP adresses are big-endian, i.e most significant byte first)
nixnax 143:c5019f856a56 385 int bufferToIP(char * buffer)
nixnax 143:c5019f856a56 386 {
nixnax 143:c5019f856a56 387 int result=0;
nixnax 143:c5019f856a56 388 for(int i=0; i<4; i++) result = (result<<8)|(*buffer++ & 0xff);
nixnax 143:c5019f856a56 389 return result;
nixnax 143:c5019f856a56 390 }
nixnax 143:c5019f856a56 391
nixnax 177:dab9e685af53 392 /// convert 4-byte ip address to 32-bit
nixnax 179:ba2b2ddd0da5 393 unsigned int ip( int a, int b, int c, int d)
nixnax 179:ba2b2ddd0da5 394 {
nixnax 177:dab9e685af53 395 return a<<24 | b<<16 | c<<8 | d;
nixnax 177:dab9e685af53 396 }
nixnax 177:dab9e685af53 397
nixnax 142:54d1543e23e5 398 /// handle IPCP configuration requests
nixnax 142:54d1543e23e5 399 void ipcpConfigRequestHandler()
nixnax 142:54d1543e23e5 400 {
nixnax 142:54d1543e23e5 401 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 173:6774a0c851c4 402 if(ppp.ipcp->request[0]==3) {
nixnax 143:c5019f856a56 403 ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax 173:6774a0c851c4 404 debugPrintf("Host IP = %d.%d.%d.%d (%08x)\n", ppp.ipcp->request[2],ppp.ipcp->request[3],ppp.ipcp->request[4],ppp.ipcp->request[5],ppp.hostIP);
nixnax 143:c5019f856a56 405 }
nixnax 143:c5019f856a56 406
nixnax 167:ff8a2d8beeb1 407 ppp.ipcp->code=2; // change code to ack
nixnax 144:01d98cf7738e 408 sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 142:54d1543e23e5 409
nixnax 142:54d1543e23e5 410 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 167:ff8a2d8beeb1 411 ppp.ipcp->code=1; // change code to request
nixnax 167:ff8a2d8beeb1 412 ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax 167:ff8a2d8beeb1 413 ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 144:01d98cf7738e 414 sendPppFrame(); // send our request
nixnax 142:54d1543e23e5 415 }
nixnax 142:54d1543e23e5 416
nixnax 142:54d1543e23e5 417 /// handle IPCP acknowledge (do nothing)
nixnax 142:54d1543e23e5 418 void ipcpAckHandler()
nixnax 142:54d1543e23e5 419 {
nixnax 142:54d1543e23e5 420 debugPrintf("Their IPCP Grant\n");
nixnax 142:54d1543e23e5 421 }
nixnax 142:54d1543e23e5 422
nixnax 143:c5019f856a56 423 /// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax 143:c5019f856a56 424 /// This is how Linux responds to an IPCP request with no options - Windows assumes any IP address on the submnet is OK.
nixnax 142:54d1543e23e5 425 void ipcpNackHandler()
nixnax 142:54d1543e23e5 426 {
nixnax 146:a45f49a2b29c 427 debugPrintf("Their IPCP Nack\n");
nixnax 173:6774a0c851c4 428 if (ppp.ipcp->request[0]==3) { // check if the NACK contains an IP address parameter
nixnax 167:ff8a2d8beeb1 429 ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax 144:01d98cf7738e 430 sendPppFrame(); // let's request this IP address as ours
nixnax 143:c5019f856a56 431 debugPrintf("Our IPCP ACK (received an IP)\n");
nixnax 146:a45f49a2b29c 432 } else { // if it's not an IP nack we ignore it
nixnax 146:a45f49a2b29c 433 debugPrintf("IPCP Nack Ignored\n");
nixnax 146:a45f49a2b29c 434 }
nixnax 142:54d1543e23e5 435 }
nixnax 142:54d1543e23e5 436
nixnax 142:54d1543e23e5 437 /// handle all other IPCP requests (by ignoring them)
nixnax 142:54d1543e23e5 438 void ipcpDefaultHandler()
nixnax 142:54d1543e23e5 439 {
nixnax 142:54d1543e23e5 440 debugPrintf("Their IPCP Other\n");
nixnax 142:54d1543e23e5 441 }
nixnax 142:54d1543e23e5 442
nixnax 142:54d1543e23e5 443 /// process an incoming IPCP packet
nixnax 142:54d1543e23e5 444 void IPCPframe()
nixnax 142:54d1543e23e5 445 {
nixnax 167:ff8a2d8beeb1 446 int action = ppp.ipcp->code; // packet type is here
nixnax 167:ff8a2d8beeb1 447 switch (action) {
nixnax 142:54d1543e23e5 448 case 1:
nixnax 142:54d1543e23e5 449 ipcpConfigRequestHandler();
nixnax 142:54d1543e23e5 450 break;
nixnax 142:54d1543e23e5 451 case 2:
nixnax 142:54d1543e23e5 452 ipcpAckHandler();
nixnax 142:54d1543e23e5 453 break;
nixnax 142:54d1543e23e5 454 case 3:
nixnax 142:54d1543e23e5 455 ipcpNackHandler();
nixnax 142:54d1543e23e5 456 break;
nixnax 142:54d1543e23e5 457 default:
nixnax 142:54d1543e23e5 458 ipcpDefaultHandler();
nixnax 142:54d1543e23e5 459 }
nixnax 142:54d1543e23e5 460 }
nixnax 142:54d1543e23e5 461
nixnax 142:54d1543e23e5 462 /// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax 161:d59f778bc8ab 463 unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax 142:54d1543e23e5 464 {
nixnax 159:4d1bf96a59cd 465 unsigned int i,hi,lo;
nixnax 142:54d1543e23e5 466 unsigned char placeHolder;
nixnax 161:d59f778bc8ab 467 if (restart) ppp.sum=0;
nixnax 142:54d1543e23e5 468 if (len&1) {
nixnax 142:54d1543e23e5 469 placeHolder = ptr[len];
nixnax 142:54d1543e23e5 470 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 471 }
nixnax 142:54d1543e23e5 472 i=0;
nixnax 142:54d1543e23e5 473 while ( i<len ) {
nixnax 142:54d1543e23e5 474 checkPc();
nixnax 142:54d1543e23e5 475 hi = ptr[i++];
nixnax 142:54d1543e23e5 476 lo = ptr[i++];
nixnax 159:4d1bf96a59cd 477 ppp.sum = ppp.sum + ((hi<<8)|lo);
nixnax 142:54d1543e23e5 478 }
nixnax 142:54d1543e23e5 479 if (len&1) {
nixnax 142:54d1543e23e5 480 ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax 142:54d1543e23e5 481 }
nixnax 159:4d1bf96a59cd 482 ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax 159:4d1bf96a59cd 483 ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax 159:4d1bf96a59cd 484 return ~ppp.sum;
nixnax 142:54d1543e23e5 485 }
nixnax 142:54d1543e23e5 486
nixnax 142:54d1543e23e5 487 /// perform the checksum on an IP header
nixnax 146:a45f49a2b29c 488 void IpHeaderCheckSum()
nixnax 142:54d1543e23e5 489 {
nixnax 161:d59f778bc8ab 490 ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax 161:d59f778bc8ab 491 int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax 161:d59f778bc8ab 492 unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax 161:d59f778bc8ab 493 ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax 146:a45f49a2b29c 494 }
nixnax 146:a45f49a2b29c 495
nixnax 147:0f40005cbc5f 496 /// swap the IP source and destination addresses
nixnax 147:0f40005cbc5f 497 void swapIpAddresses()
nixnax 147:0f40005cbc5f 498 {
nixnax 162:594729c0e5c1 499 unsigned int tempHold;
nixnax 162:594729c0e5c1 500 tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax 162:594729c0e5c1 501 ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax 162:594729c0e5c1 502 ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax 147:0f40005cbc5f 503 }
nixnax 147:0f40005cbc5f 504
nixnax 149:969d98f6fb88 505 /// swap the IP source and destination ports
nixnax 149:969d98f6fb88 506 void swapIpPorts()
nixnax 149:969d98f6fb88 507 {
nixnax 173:6774a0c851c4 508 int headerSizeIP = 4 * (ppp.ip->headerLength); // calculate size of IP header
nixnax 173:6774a0c851c4 509 char * ipSrcPort = ppp.ipStart + headerSizeIP + 0; // ip source port location
nixnax 173:6774a0c851c4 510 char * ipDstPort = ppp.ipStart + headerSizeIP + 2; // ip destin port location
nixnax 149:969d98f6fb88 511 char tempHold[2];
nixnax 149:969d98f6fb88 512 memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax 149:969d98f6fb88 513 memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax 149:969d98f6fb88 514 memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax 149:969d98f6fb88 515 }
nixnax 149:969d98f6fb88 516
nixnax 170:3d3b2126181c 517 /// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax 170:3d3b2126181c 518 void checkSumPseudoHeader( unsigned int packetLength )
nixnax 170:3d3b2126181c 519 {
nixnax 170:3d3b2126181c 520 // this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax 170:3d3b2126181c 521 pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax 170:3d3b2126181c 522 pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax 170:3d3b2126181c 523 pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax 170:3d3b2126181c 524 pseudoHeader.zero = 0; // zero byte
nixnax 170:3d3b2126181c 525 pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax 170:3d3b2126181c 526 pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax 170:3d3b2126181c 527 dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax 170:3d3b2126181c 528 }
nixnax 170:3d3b2126181c 529
nixnax 171:46b36d4edd1d 530 /// initialize an IP packet to send
nixnax 171:46b36d4edd1d 531 void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax 171:46b36d4edd1d 532 {
nixnax 171:46b36d4edd1d 533 ppp.ppp->address = 0xff;
nixnax 171:46b36d4edd1d 534 ppp.ppp->control = 3;
nixnax 171:46b36d4edd1d 535 ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax 171:46b36d4edd1d 536 ppp.ip->version = 4;
nixnax 171:46b36d4edd1d 537 ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax 171:46b36d4edd1d 538 ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax 171:46b36d4edd1d 539 ppp.ip->dontFragment=1;
nixnax 171:46b36d4edd1d 540 ppp.ip->ttl=128;
nixnax 171:46b36d4edd1d 541 ppp.ip->protocol = protocol; // udp
nixnax 171:46b36d4edd1d 542 ppp.ip->srcAdrR = __REV(srcIp);
nixnax 171:46b36d4edd1d 543 ppp.ip->dstAdrR = __REV(dstIp);
nixnax 171:46b36d4edd1d 544 ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax 171:46b36d4edd1d 545 ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax 171:46b36d4edd1d 546 ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax 171:46b36d4edd1d 547 }
nixnax 171:46b36d4edd1d 548
nixnax 171:46b36d4edd1d 549
nixnax 171:46b36d4edd1d 550 /// Build a UDP packet from scratch
nixnax 171:46b36d4edd1d 551 void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax 171:46b36d4edd1d 552 {
nixnax 171:46b36d4edd1d 553 struct {
nixnax 171:46b36d4edd1d 554 unsigned int ipAll; // length of entire ip packet
nixnax 171:46b36d4edd1d 555 unsigned int ipHeader; // length of ip header
nixnax 171:46b36d4edd1d 556 unsigned int udpAll; // length of entire udp packet
nixnax 171:46b36d4edd1d 557 unsigned int udpData; // length of udp data segment
nixnax 171:46b36d4edd1d 558 } len;
nixnax 171:46b36d4edd1d 559 len.ipHeader = 20; // ip header length
nixnax 171:46b36d4edd1d 560 len.udpData = msgLen; // udp data size
nixnax 171:46b36d4edd1d 561 len.udpAll = len.udpData+8; // update local udp packet length
nixnax 171:46b36d4edd1d 562 len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax 171:46b36d4edd1d 563 initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax 171:46b36d4edd1d 564 ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax 171:46b36d4edd1d 565 ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax 171:46b36d4edd1d 566 memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax 171:46b36d4edd1d 567 ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax 171:46b36d4edd1d 568 ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax 171:46b36d4edd1d 569 IpHeaderCheckSum(); // refresh IP header checksum
nixnax 171:46b36d4edd1d 570 checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax 171:46b36d4edd1d 571 ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 171:46b36d4edd1d 572 unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax 171:46b36d4edd1d 573 ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 171:46b36d4edd1d 574 sendPppFrame(); // send the UDP message back
nixnax 171:46b36d4edd1d 575 }
nixnax 171:46b36d4edd1d 576
nixnax 146:a45f49a2b29c 577 /// Process an incoming UDP packet.
nixnax 146:a45f49a2b29c 578 /// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax 146:a45f49a2b29c 579 void UDPpacket()
nixnax 146:a45f49a2b29c 580 {
nixnax 163:d1b4328e9f08 581 struct {
nixnax 163:d1b4328e9f08 582 unsigned int all; // length of entire ip packet
nixnax 163:d1b4328e9f08 583 unsigned int header; // length of ip header
nixnax 163:d1b4328e9f08 584 } ipLength;
nixnax 163:d1b4328e9f08 585
nixnax 163:d1b4328e9f08 586 struct {
nixnax 165:c47826d07e0d 587 unsigned int all; // length of entire udp packet
nixnax 163:d1b4328e9f08 588 unsigned int data; // length of udp data segment
nixnax 163:d1b4328e9f08 589 } udpLength;
nixnax 163:d1b4328e9f08 590
nixnax 163:d1b4328e9f08 591 ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax 163:d1b4328e9f08 592 ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax 171:46b36d4edd1d 593 udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax 163:d1b4328e9f08 594 udpLength.data = udpLength.all - 8; // size of udp data
nixnax 147:0f40005cbc5f 595
nixnax 146:a45f49a2b29c 596 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 171:46b36d4edd1d 597 char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax 171:46b36d4edd1d 598 char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax 163:d1b4328e9f08 599
nixnax 171:46b36d4edd1d 600 unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax 171:46b36d4edd1d 601 unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax 163:d1b4328e9f08 602
nixnax 163:d1b4328e9f08 603 if(v0) {
nixnax 163:d1b4328e9f08 604 debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax 163:d1b4328e9f08 605 debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax 163:d1b4328e9f08 606 debugPrintf("Len %03d", udpLength);
nixnax 163:d1b4328e9f08 607 }
nixnax 146:a45f49a2b29c 608 if (v1) {
nixnax 163:d1b4328e9f08 609 int printSize = udpLength.data;
nixnax 146:a45f49a2b29c 610 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 146:a45f49a2b29c 611 for (int i=0; i<printSize; i++) {
nixnax 163:d1b4328e9f08 612 char ch = ppp.udp->data[i];
nixnax 146:a45f49a2b29c 613 if (ch>31 && ch<127) {
nixnax 146:a45f49a2b29c 614 debugPrintf("%c", ch);
nixnax 146:a45f49a2b29c 615 } else {
nixnax 146:a45f49a2b29c 616 debugPrintf("_");
nixnax 146:a45f49a2b29c 617 }
nixnax 146:a45f49a2b29c 618 }
nixnax 146:a45f49a2b29c 619 }
nixnax 146:a45f49a2b29c 620 if (v0) debugPrintf("\n");
nixnax 146:a45f49a2b29c 621 #endif
nixnax 163:d1b4328e9f08 622 int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax 163:d1b4328e9f08 623 int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax 146:a45f49a2b29c 624 if ( (echoFound) || (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax 146:a45f49a2b29c 625 if (echoFound) {
nixnax 171:46b36d4edd1d 626 swapIpAddresses(); // swap IP source and destination
nixnax 171:46b36d4edd1d 627 swapIpPorts(); // swap IP source and destination ports
nixnax 163:d1b4328e9f08 628 memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax 170:3d3b2126181c 629 int n=0;
nixnax 170:3d3b2126181c 630 n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax 168:c77eb908042a 631 udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax 171:46b36d4edd1d 632 // we may have changed data length, update all the lengths
nixnax 171:46b36d4edd1d 633 udpLength.all = udpLength.data+8; // update local udp packet length
nixnax 171:46b36d4edd1d 634 ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax 171:46b36d4edd1d 635 ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax 171:46b36d4edd1d 636 ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax 171:46b36d4edd1d 637 ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax 171:46b36d4edd1d 638 IpHeaderCheckSum(); // refresh IP header checksum
nixnax 171:46b36d4edd1d 639 checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax 171:46b36d4edd1d 640 ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 171:46b36d4edd1d 641 unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax 171:46b36d4edd1d 642 ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 171:46b36d4edd1d 643 sendPppFrame(); // send the UDP message back
nixnax 171:46b36d4edd1d 644 } else if ( testFound ) {
nixnax 171:46b36d4edd1d 645 unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax 171:46b36d4edd1d 646 unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax 171:46b36d4edd1d 647 unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax 171:46b36d4edd1d 648 unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax 172:449dd7a28955 649 int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter);
nixnax 171:46b36d4edd1d 650 sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax 146:a45f49a2b29c 651 }
nixnax 146:a45f49a2b29c 652 }
nixnax 142:54d1543e23e5 653 }
nixnax 142:54d1543e23e5 654
nixnax 174:e5a3f16421a5 655 /// UDP demo that sends a udp packet containing a character received from the second debug serial port.
nixnax 174:e5a3f16421a5 656 /// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
nixnax 178:3f17aa0ce5ce 657 /// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
nixnax 178:3f17aa0ce5ce 658 /// See http://www.wikihow.com/Enable-IP-Routing.
nixnax 179:ba2b2ddd0da5 659 /// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
nixnax 179:ba2b2ddd0da5 660 /// The netcat UDP receive command on the remote host would be: nc -ul 12345
nixnax 174:e5a3f16421a5 661 void sendUdpData()
nixnax 174:e5a3f16421a5 662 {
nixnax 174:e5a3f16421a5 663 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 179:ba2b2ddd0da5 664 if (ppp.online) {
nixnax 179:ba2b2ddd0da5 665 if (xx.readable()) {
nixnax 179:ba2b2ddd0da5 666 char inchar = xx.getc();
nixnax 179:ba2b2ddd0da5 667 xx.putc( inchar ); // echo the received character on the debug serial port
nixnax 179:ba2b2ddd0da5 668 sendUdp(ip(172,10,10,2), ip(192,168,0,109), 1, 12345, &inchar, 1); // send a 1 byte UDP message to a remote machine at IP 192.168.0.109:12345
nixnax 179:ba2b2ddd0da5 669 }
nixnax 174:e5a3f16421a5 670 }
nixnax 174:e5a3f16421a5 671 #endif
nixnax 174:e5a3f16421a5 672 }
nixnax 174:e5a3f16421a5 673
nixnax 142:54d1543e23e5 674 /// handle a PING ICMP (internet control message protocol) packet
nixnax 142:54d1543e23e5 675 void ICMPpacket() // internet control message protocol
nixnax 142:54d1543e23e5 676 {
nixnax 165:c47826d07e0d 677 struct {
nixnax 165:c47826d07e0d 678 unsigned int all; // length of entire ip packet
nixnax 165:c47826d07e0d 679 unsigned int header; // length of ip header
nixnax 165:c47826d07e0d 680 } ipLength;
nixnax 165:c47826d07e0d 681 struct {
nixnax 165:c47826d07e0d 682 unsigned int all; // length of entire udp packet
nixnax 165:c47826d07e0d 683 unsigned int data; // length of udp data segment
nixnax 165:c47826d07e0d 684 } icmpLength;
nixnax 165:c47826d07e0d 685 ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax 165:c47826d07e0d 686 ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax 165:c47826d07e0d 687 ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax 165:c47826d07e0d 688 icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax 165:c47826d07e0d 689 icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax 142:54d1543e23e5 690 #define ICMP_TYPE_PING_REQUEST 8
nixnax 165:c47826d07e0d 691 if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax 165:c47826d07e0d 692 ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax 147:0f40005cbc5f 693 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 167:ff8a2d8beeb1 694 char * srcAdr = ppp.ip->srcAdrPtr;
nixnax 167:ff8a2d8beeb1 695 char * dstAdr = ppp.ip->dstAdrPtr;
nixnax 165:c47826d07e0d 696 int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax 165:c47826d07e0d 697 int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax 142:54d1543e23e5 698 if(1) {
nixnax 142:54d1543e23e5 699 char pbuf[50];
nixnax 142:54d1543e23e5 700 checkPc();
nixnax 142:54d1543e23e5 701 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 702 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 703 checkPc();
nixnax 142:54d1543e23e5 704 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 142:54d1543e23e5 705 checkPc();
nixnax 142:54d1543e23e5 706 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 707 }
nixnax 142:54d1543e23e5 708 #endif
nixnax 147:0f40005cbc5f 709 swapIpAddresses(); // swap the IP source and destination addresses
nixnax 147:0f40005cbc5f 710 IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax 142:54d1543e23e5 711 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 165:c47826d07e0d 712 ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 165:c47826d07e0d 713 ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax 165:c47826d07e0d 714 unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax 165:c47826d07e0d 715 ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax 142:54d1543e23e5 716
nixnax 165:c47826d07e0d 717 int printSize = icmpLength.data; // exclude size of icmp header
nixnax 142:54d1543e23e5 718 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 142:54d1543e23e5 719 if (0) {
nixnax 142:54d1543e23e5 720 for (int i=0; i<printSize; i++) {
nixnax 165:c47826d07e0d 721 char ch = ppp.icmp->data[i];
nixnax 142:54d1543e23e5 722 if (ch>31 && ch<127) {
nixnax 142:54d1543e23e5 723 putcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 724 } else {
nixnax 142:54d1543e23e5 725 putcWhileCheckingInput('_');
nixnax 142:54d1543e23e5 726 }
nixnax 142:54d1543e23e5 727 }
nixnax 142:54d1543e23e5 728 putcWhileCheckingInput('\n');
nixnax 142:54d1543e23e5 729 }
nixnax 144:01d98cf7738e 730 sendPppFrame(); // reply to the ping
nixnax 142:54d1543e23e5 731 } else {
nixnax 142:54d1543e23e5 732 if (v0) {
nixnax 165:c47826d07e0d 733 debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax 142:54d1543e23e5 734 }
nixnax 142:54d1543e23e5 735 }
nixnax 142:54d1543e23e5 736 }
nixnax 142:54d1543e23e5 737
nixnax 142:54d1543e23e5 738 /// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax 142:54d1543e23e5 739 void IGMPpacket()
nixnax 142:54d1543e23e5 740 {
nixnax 142:54d1543e23e5 741 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 142:54d1543e23e5 742 }
nixnax 142:54d1543e23e5 743
nixnax 142:54d1543e23e5 744 /// dump the header of an IP pakcet on the (optional) debug serial port
nixnax 142:54d1543e23e5 745 void dumpHeaderIP (int outGoing)
nixnax 142:54d1543e23e5 746 {
nixnax 142:54d1543e23e5 747 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 142:54d1543e23e5 748 checkPc(); // we are expecting the first character of the next packet
nixnax 155:9c6a1d249e26 749 int IPv4Id = __REV16(ppp.ip->identR);
nixnax 152:025c73b6c0a9 750 char pbuf[80]; // local print buffer
nixnax 142:54d1543e23e5 751 int n=0;
nixnax 142:54d1543e23e5 752 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 142:54d1543e23e5 753 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 754 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 142:54d1543e23e5 755 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 167:ff8a2d8beeb1 756 char * srcAdr = ppp.ip->srcAdrPtr;
nixnax 167:ff8a2d8beeb1 757 char * dstAdr = ppp.ip->dstAdrPtr;
nixnax 142:54d1543e23e5 758 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 759 #endif
nixnax 142:54d1543e23e5 760 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 761 #ifndef TCP_HEADER_DUMP_YES
nixnax 160:bd701ad564cb 762 putsWhileCheckingInput('\x1b[30m\n'); // if there's no TCP header dump we terminate the line with \n and VT100 code for black
nixnax 142:54d1543e23e5 763 #endif
nixnax 142:54d1543e23e5 764 #endif
nixnax 142:54d1543e23e5 765 }
nixnax 142:54d1543e23e5 766
nixnax 142:54d1543e23e5 767 /// dump a TCP header on the optional debug serial port
nixnax 142:54d1543e23e5 768 void dumpHeaderTCP(int outGoing)
nixnax 142:54d1543e23e5 769 {
nixnax 142:54d1543e23e5 770 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 155:9c6a1d249e26 771 char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax 142:54d1543e23e5 772 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 142:54d1543e23e5 773 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 155:9c6a1d249e26 774 memset(flagString,'.', 8); // fill string with "........"
nixnax 156:163c23249731 775 if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax 156:163c23249731 776 if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax 156:163c23249731 777 if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax 156:163c23249731 778 if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax 156:163c23249731 779 if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax 156:163c23249731 780 if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax 156:163c23249731 781 if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax 156:163c23249731 782 if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax 155:9c6a1d249e26 783 flagString[8]=0; // null terminate string
nixnax 142:54d1543e23e5 784 #else
nixnax 156:163c23249731 785 if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax 156:163c23249731 786 if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax 156:163c23249731 787 if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax 156:163c23249731 788 if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax 156:163c23249731 789 if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax 155:9c6a1d249e26 790 flagString[1]=0; // null terminate string
nixnax 142:54d1543e23e5 791 #endif
nixnax 155:9c6a1d249e26 792 putsWhileCheckingInput( flagString );
nixnax 142:54d1543e23e5 793 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 794 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 795 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 160:bd701ad564cb 796 #else
nixnax 160:bd701ad564cb 797 putsWhileCheckingInput("\x1b[30m"); // write a black color after every packet
nixnax 142:54d1543e23e5 798 #endif
nixnax 156:163c23249731 799 if( outGoing && ppp.tcp->flag.fin ) { // ACK/FIN - if this is an outgoing FIN it's the end of a tcp conversation
nixnax 160:bd701ad564cb 800 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax 142:54d1543e23e5 801 }
nixnax 142:54d1543e23e5 802 #endif
nixnax 142:54d1543e23e5 803 }
nixnax 142:54d1543e23e5 804
nixnax 143:c5019f856a56 805 /// Encode a buffer in base-64
nixnax 184:4133f557d4d4 806 const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax 142:54d1543e23e5 807 void enc64(char * in, char * out, int len)
nixnax 142:54d1543e23e5 808 {
nixnax 142:54d1543e23e5 809 int i,j,a,b,c;
nixnax 142:54d1543e23e5 810 i=0;
nixnax 142:54d1543e23e5 811 j=0;
nixnax 142:54d1543e23e5 812 while(1) {
nixnax 142:54d1543e23e5 813 if (i<len) {
nixnax 142:54d1543e23e5 814 a = in[i++];
nixnax 142:54d1543e23e5 815 out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax 142:54d1543e23e5 816 } else break;
nixnax 142:54d1543e23e5 817 if (i<len) {
nixnax 142:54d1543e23e5 818 b = in[i++];
nixnax 142:54d1543e23e5 819 out[j++] = lut[ ( (a << 4) & 0x30) | ( (b >> 4) & 0x0f) ];
nixnax 142:54d1543e23e5 820 out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax 142:54d1543e23e5 821 } else out[j++] = '=';
nixnax 142:54d1543e23e5 822 if (i<len) {
nixnax 142:54d1543e23e5 823 c = in[i++];
nixnax 142:54d1543e23e5 824 j--;
nixnax 142:54d1543e23e5 825 out[j++] = lut[ ( (b << 2) & 0x3c) | ( (c >> 6) & 0x03) ];
nixnax 142:54d1543e23e5 826 out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax 142:54d1543e23e5 827 } else out[j++] = '=';
nixnax 142:54d1543e23e5 828 }
nixnax 142:54d1543e23e5 829 out[j]=0;
nixnax 142:54d1543e23e5 830 }
nixnax 142:54d1543e23e5 831
nixnax 160:bd701ad564cb 832 /// Handle a request for an http websocket.
nixnax 160:bd701ad564cb 833 /// 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 834 int webSocketHandler(char * dataStart)
nixnax 142:54d1543e23e5 835 {
nixnax 142:54d1543e23e5 836 int n=0; // byte counter
nixnax 184:4133f557d4d4 837 char * key = strstr(dataStart, "Sec-WebSocket-Key:"); // search for the key in the payload
nixnax 142:54d1543e23e5 838 if (key != NULL) {
nixnax 184:4133f557d4d4 839 key = key + 18; // skip over the key ident string "Sec-WebSocket-Key:"
nixnax 142:54d1543e23e5 840 if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax 184:4133f557d4d4 841 while ( strchr(lut, *key) == NULL) key++; // skip non-valid base-64 characters (whitespace)
nixnax 184:4133f557d4d4 842 char challenge [80];
nixnax 184:4133f557d4d4 843 int i=0;
nixnax 184:4133f557d4d4 844 char * copyTo = challenge;
nixnax 184:4133f557d4d4 845 while (strchr(lut, *key) != NULL) { // copy while we see valid base-64 characters
nixnax 184:4133f557d4d4 846 if (i++ >40) break; // prevent buffer overflow
nixnax 184:4133f557d4d4 847 *copyTo++ = *key++; // copy next valid base-64 character
nixnax 184:4133f557d4d4 848 }
nixnax 184:4133f557d4d4 849 strcpy(copyTo,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // append websocket gui code
nixnax 184:4133f557d4d4 850 if (0) debugPrintf("Challenge is %s\n", challenge); // the string we hash for the challenge
nixnax 142:54d1543e23e5 851 char shaOutput [20]; // sha1 output
nixnax 184:4133f557d4d4 852 sha1( shaOutput, challenge, strlen(challenge)); // hash the challenge
nixnax 142:54d1543e23e5 853 char encOut[50];
nixnax 184:4133f557d4d4 854 enc64( shaOutput, encOut, 20); // base-64 encode
nixnax 142:54d1543e23e5 855 char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax 142:54d1543e23e5 856 char * version = challenge;
nixnax 184:4133f557d4d4 857 strncpy(version, versionstring,70); // copy their version string
nixnax 142:54d1543e23e5 858 *strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax 142:54d1543e23e5 859 memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax 142:54d1543e23e5 860 n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax 142:54d1543e23e5 861 n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax 142:54d1543e23e5 862 n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax 142:54d1543e23e5 863 n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax 142:54d1543e23e5 864 n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax 142:54d1543e23e5 865 n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax 142:54d1543e23e5 866 n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax 142:54d1543e23e5 867 }
nixnax 142:54d1543e23e5 868 return n; // this response should satisfy a web browser's websocket protocol request
nixnax 142:54d1543e23e5 869 }
nixnax 142:54d1543e23e5 870
nixnax 142:54d1543e23e5 871 #define TCP_FLAG_ACK (1<<4)
nixnax 142:54d1543e23e5 872 #define TCP_FLAG_SYN (1<<1)
nixnax 142:54d1543e23e5 873 #define TCP_FLAG_PSH (1<<3)
nixnax 142:54d1543e23e5 874 #define TCP_FLAG_RST (1<<2)
nixnax 142:54d1543e23e5 875 #define TCP_FLAG_FIN (1<<0)
nixnax 142:54d1543e23e5 876
nixnax 142:54d1543e23e5 877 /// respond to an HTTP request
nixnax 185:4cd8f91e9d49 878 int httpResponse(char * dataStart, int * flags)
nixnax 142:54d1543e23e5 879 {
nixnax 142:54d1543e23e5 880 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 881 n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax 160:bd701ad564cb 882 if (n>0) return n; // if n>0 we already have a response, so return
nixnax 142:54d1543e23e5 883
nixnax 142:54d1543e23e5 884 int nHeader; // byte size of HTTP header
nixnax 142:54d1543e23e5 885 int contentLengthStart; // index where HTML starts
nixnax 142:54d1543e23e5 886 int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax 185:4cd8f91e9d49 887 *flags = TCP_FLAG_ACK | TCP_FLAG_FIN; // the default case is that we close the connection
nixnax 142:54d1543e23e5 888
nixnax 142:54d1543e23e5 889 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax 142:54d1543e23e5 890 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 891 httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 892 httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 893 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 142:54d1543e23e5 894 if( (httpGetRoot==0) || (httpGetx==0) ) {
nixnax 142:54d1543e23e5 895 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax 142:54d1543e23e5 896 } else {
nixnax 142:54d1543e23e5 897 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 142:54d1543e23e5 898 }
nixnax 142:54d1543e23e5 899 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 142:54d1543e23e5 900 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 142:54d1543e23e5 901 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 142:54d1543e23e5 902 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 142:54d1543e23e5 903 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 904 nHeader=n; // size of HTTP header
nixnax 185:4cd8f91e9d49 905
nixnax 142:54d1543e23e5 906 if( httpGetRoot == 0 ) {
nixnax 142:54d1543e23e5 907 // this is where we insert our web page into the buffer
nixnax 142:54d1543e23e5 908 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 142:54d1543e23e5 909 n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax 185:4cd8f91e9d49 910
nixnax 142:54d1543e23e5 911 } else if ( (httpGet5 == 'w') && (httpGet6 == 's') ) { // "ws" is a special page for websocket demo
nixnax 142:54d1543e23e5 912 memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax 142:54d1543e23e5 913 n = n + sizeof(webSocketPage)-1; // one less than size
nixnax 185:4cd8f91e9d49 914 *flags = TCP_FLAG_ACK | TCP_FLAG_PSH; // for a websocket page we do NOT close the connection
nixnax 142:54d1543e23e5 915 } else {
nixnax 142:54d1543e23e5 916 if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax 142:54d1543e23e5 917 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 142:54d1543e23e5 918 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 142:54d1543e23e5 919 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 142:54d1543e23e5 920 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax 146:a45f49a2b29c 921 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax 142:54d1543e23e5 922 #else
nixnax 142:54d1543e23e5 923 if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax 167:ff8a2d8beeb1 924 n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax 142:54d1543e23e5 925 }
nixnax 142:54d1543e23e5 926 // /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax 146:a45f49a2b29c 927 n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax 142:54d1543e23e5 928 #endif
nixnax 142:54d1543e23e5 929 } else {
nixnax 142:54d1543e23e5 930 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 142:54d1543e23e5 931 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax 142:54d1543e23e5 932 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 142:54d1543e23e5 933 }
nixnax 142:54d1543e23e5 934 }
nixnax 142:54d1543e23e5 935 #define CONTENTLENGTHSIZE 5
nixnax 142:54d1543e23e5 936 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 142:54d1543e23e5 937 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 142:54d1543e23e5 938 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 142:54d1543e23e5 939 return n; // total byte size of our response
nixnax 142:54d1543e23e5 940 }
nixnax 142:54d1543e23e5 941
nixnax 160:bd701ad564cb 942 /// Handle TCP data that is not an HTTP GET.
nixnax 160:bd701ad564cb 943 /// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax 160:bd701ad564cb 944 /// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax 142:54d1543e23e5 945 int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax 142:54d1543e23e5 946 {
nixnax 142:54d1543e23e5 947 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 948 if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax 160:bd701ad564cb 949 char mask [4];
nixnax 160:bd701ad564cb 950 memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax 160:bd701ad564cb 951 int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax 160:bd701ad564cb 952 if((dataStart[1]&0x80)==0x80) // test if the mask bit is set, which means all data is xor'ed with the mask
nixnax 160:bd701ad564cb 953 for (int i=0; i<websocketMessageSize; i++) dataStart[i+6]^= mask[i%4]; // unmask each byte with one of the mask bytes
nixnax 160:bd701ad564cb 954 dataStart[1] = len-2; // add four extra bytes to the message length because we don't use mask bytes for the send
nixnax 160:bd701ad564cb 955 memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax 160:bd701ad564cb 956 n = len; // our response size remains exactly the same length as what we received
nixnax 142:54d1543e23e5 957 } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax 142:54d1543e23e5 958 n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax 142:54d1543e23e5 959 dataStart[1]=0; // we don't have mask bytes on
nixnax 160:bd701ad564cb 960 } else {
nixnax 184:4133f557d4d4 961 if ( len > 1 ) { // we assume a length of 1 is a keep-alive or push packet
nixnax 184:4133f557d4d4 962 if (v1) putsWhileCheckingInput("TCP data received\n"); // all other tcp push packets
nixnax 184:4133f557d4d4 963 }
nixnax 163:d1b4328e9f08 964 }
nixnax 142:54d1543e23e5 965 return n; // total byte size of our response
nixnax 142:54d1543e23e5 966 }
nixnax 142:54d1543e23e5 967
nixnax 173:6774a0c851c4 968 /// dump the TCP data to the debug serial port
nixnax 173:6774a0c851c4 969 void dumpDataTCP(int outGoing)
nixnax 173:6774a0c851c4 970 {
nixnax 173:6774a0c851c4 971 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 173:6774a0c851c4 972 if (v2) {
nixnax 173:6774a0c851c4 973 int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax 173:6774a0c851c4 974 int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax 173:6774a0c851c4 975 ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax 173:6774a0c851c4 976 int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax 173:6774a0c851c4 977 ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
nixnax 173:6774a0c851c4 978 int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax 173:6774a0c851c4 979 int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax 173:6774a0c851c4 980 char pbuf[80]; // local print buffer
nixnax 173:6774a0c851c4 981 int n=0;
nixnax 173:6774a0c851c4 982 checkPc();
nixnax 173:6774a0c851c4 983 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 173:6774a0c851c4 984 checkPc();
nixnax 173:6774a0c851c4 985 n=n+sprintf(pbuf+n, "IP:%d ipHeader:%d tcpHeader:%d tcpData:%d\n", packetLengthIp, headerSizeIp, headerSizeTcp, tcpDataSize); // 1 for more verbose
nixnax 184:4133f557d4d4 986 if (n>70) putsWhileCheckingInput("n>pbuf overflow in dumpDataTCP()\n");
nixnax 173:6774a0c851c4 987 checkPc();
nixnax 173:6774a0c851c4 988 putsWhileCheckingInput( pbuf );
nixnax 173:6774a0c851c4 989 if (tcpDataSize > 0) {
nixnax 173:6774a0c851c4 990 ppp.tcpData[tcpDataSize]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 173:6774a0c851c4 991 putsWhileCheckingInput( ppp.tcpData ); // print the tcp payload data
nixnax 173:6774a0c851c4 992 putsWhileCheckingInput("\n");
nixnax 173:6774a0c851c4 993 }
nixnax 173:6774a0c851c4 994 putsWhileCheckingInput( "\x1b[30m" ); // VT100 color code, print black
nixnax 173:6774a0c851c4 995 }
nixnax 173:6774a0c851c4 996 #endif
nixnax 173:6774a0c851c4 997 }
nixnax 173:6774a0c851c4 998
nixnax 142:54d1543e23e5 999 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 1000 /// 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 1001 void tcpHandler()
nixnax 142:54d1543e23e5 1002 {
nixnax 154:18b2bd92f557 1003 int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax 154:18b2bd92f557 1004 int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax 173:6774a0c851c4 1005 ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate TCP header start
nixnax 154:18b2bd92f557 1006 int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax 154:18b2bd92f557 1007 int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax 173:6774a0c851c4 1008 char * tcpDataIn = ppp.tcpStart + headerSizeTcp; // start of data TCP data after TCP header
nixnax 154:18b2bd92f557 1009 int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax 154:18b2bd92f557 1010
nixnax 154:18b2bd92f557 1011 unsigned int seq_in = __REV(ppp.tcp->seqTcpR);
nixnax 154:18b2bd92f557 1012 unsigned int ack_in = __REV(ppp.tcp->ackTcpR);
nixnax 142:54d1543e23e5 1013 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 142:54d1543e23e5 1014 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 142:54d1543e23e5 1015
nixnax 142:54d1543e23e5 1016 // first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax 173:6774a0c851c4 1017 headerSizeIp=20;
nixnax 173:6774a0c851c4 1018 ppp.ip->headerLength = headerSizeIp/4; // ip header is 20 bytes long
nixnax 173:6774a0c851c4 1019 ppp.ip->lengthR = __REV(40); // 20 ip header + 20 tcp header
nixnax 173:6774a0c851c4 1020 //tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 154:18b2bd92f557 1021 headerSizeTcp = 20; // shorten outgoing TCP header size 20 bytes
nixnax 173:6774a0c851c4 1022 ppp.tcpStart = ppp.ipStart + headerSizeIp; // recalc TCP header start
nixnax 154:18b2bd92f557 1023 ppp.tcp->offset = (headerSizeTcp/4);
nixnax 173:6774a0c851c4 1024 char * tcpDataOut = ppp.tcpStart + headerSizeTcp; // start of outgoing data
nixnax 142:54d1543e23e5 1025
nixnax 142:54d1543e23e5 1026 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 142:54d1543e23e5 1027 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 160:bd701ad564cb 1028
nixnax 185:4cd8f91e9d49 1029 ppp.tcp->windowR = __REV16( 1200 ); // set tcp window size to 1200 bytes
nixnax 142:54d1543e23e5 1030
nixnax 142:54d1543e23e5 1031 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 142:54d1543e23e5 1032
nixnax 156:163c23249731 1033 switch ( ppp.tcp->flag.All ) {
nixnax 142:54d1543e23e5 1034 case TCP_FLAG_SYN:
nixnax 142:54d1543e23e5 1035 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 142:54d1543e23e5 1036 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 142:54d1543e23e5 1037 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 1038 break;
nixnax 184:4133f557d4d4 1039 case TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1040 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 184:4133f557d4d4 1041 if ( (ppp.tcp->flag.All == TCP_FLAG_ACK) && (tcpDataSize == 0)) return; // handle zero-size ack messages by ignoring them
nixnax 142:54d1543e23e5 1042 if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax 179:ba2b2ddd0da5 1043 flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // we have data, set the PSH flag
nixnax 185:4cd8f91e9d49 1044 dataLen = httpResponse(tcpDataOut, &flagsOut); // send an http response
nixnax 142:54d1543e23e5 1045 } else {
nixnax 158:841592aed956 1046 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax 179:ba2b2ddd0da5 1047 if (dataLen > 0) flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // if we have any data set the PSH flag
nixnax 142:54d1543e23e5 1048 }
nixnax 142:54d1543e23e5 1049 break;
nixnax 142:54d1543e23e5 1050 case TCP_FLAG_FIN:
nixnax 142:54d1543e23e5 1051 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1052 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1053 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 142:54d1543e23e5 1054 ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 1055 break;
nixnax 142:54d1543e23e5 1056 default:
nixnax 179:ba2b2ddd0da5 1057 return; // ignore all other packets
nixnax 142:54d1543e23e5 1058 } // switch
nixnax 142:54d1543e23e5 1059
nixnax 142:54d1543e23e5 1060 // The TCP flag handling is now done
nixnax 142:54d1543e23e5 1061 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 147:0f40005cbc5f 1062 swapIpAddresses(); // swap IP source and destination addresses
nixnax 149:969d98f6fb88 1063 swapIpPorts(); // swap IP source and destination ports
nixnax 142:54d1543e23e5 1064
nixnax 158:841592aed956 1065 ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax 158:841592aed956 1066 ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax 160:bd701ad564cb 1067
nixnax 156:163c23249731 1068 ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax 142:54d1543e23e5 1069
nixnax 159:4d1bf96a59cd 1070 // recalculate all the header sizes
nixnax 154:18b2bd92f557 1071 tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax 154:18b2bd92f557 1072 int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax 159:4d1bf96a59cd 1073 ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax 142:54d1543e23e5 1074 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 1075
nixnax 142:54d1543e23e5 1076 // the header is all set up, now do the IP and TCP checksums
nixnax 146:a45f49a2b29c 1077 IpHeaderCheckSum(); // calculate new IP header checksum
nixnax 170:3d3b2126181c 1078 checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax 159:4d1bf96a59cd 1079 ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 161:d59f778bc8ab 1080 unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax 159:4d1bf96a59cd 1081 ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 160:bd701ad564cb 1082
nixnax 170:3d3b2126181c 1083 dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax 170:3d3b2126181c 1084 dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax 173:6774a0c851c4 1085 dumpDataTCP(1); // dump outgoing TCP data before sending the frame
nixnax 182:f039ec218c9f 1086 if (0) wait_ms(45); // 45 ms delay before sending frame - a typical internet delay time
nixnax 144:01d98cf7738e 1087 sendPppFrame(); // All preparation complete - send the TCP response
nixnax 142:54d1543e23e5 1088 if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
nixnax 142:54d1543e23e5 1089 memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax 142:54d1543e23e5 1090 }
nixnax 142:54d1543e23e5 1091
nixnax 142:54d1543e23e5 1092 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 1093 void TCPpacket()
nixnax 142:54d1543e23e5 1094 {
nixnax 173:6774a0c851c4 1095 dumpHeaderIP(0); // dump incoming packet IP header
nixnax 173:6774a0c851c4 1096 dumpHeaderTCP(0); // dump incoming packet TCP header
nixnax 173:6774a0c851c4 1097 dumpDataTCP(0); // dump incoming packet data
nixnax 142:54d1543e23e5 1098 tcpHandler();
nixnax 142:54d1543e23e5 1099 }
nixnax 142:54d1543e23e5 1100
nixnax 142:54d1543e23e5 1101 /// handle the remaining IP protocols by ignoring them
nixnax 142:54d1543e23e5 1102 void otherProtocol()
nixnax 142:54d1543e23e5 1103 {
nixnax 142:54d1543e23e5 1104 debugPrintf("Other IP protocol");
nixnax 142:54d1543e23e5 1105 }
nixnax 142:54d1543e23e5 1106
nixnax 142:54d1543e23e5 1107 /// process an incoming IP packet
nixnax 142:54d1543e23e5 1108 void IPframe()
nixnax 142:54d1543e23e5 1109 {
nixnax 167:ff8a2d8beeb1 1110 int protocol = ppp.ip->protocol;
nixnax 142:54d1543e23e5 1111 switch (protocol) {
nixnax 142:54d1543e23e5 1112 case 1:
nixnax 142:54d1543e23e5 1113 ICMPpacket();
nixnax 142:54d1543e23e5 1114 break;
nixnax 142:54d1543e23e5 1115 case 2:
nixnax 142:54d1543e23e5 1116 IGMPpacket();
nixnax 142:54d1543e23e5 1117 break;
nixnax 142:54d1543e23e5 1118 case 17:
nixnax 142:54d1543e23e5 1119 UDPpacket();
nixnax 142:54d1543e23e5 1120 break;
nixnax 142:54d1543e23e5 1121 case 6:
nixnax 142:54d1543e23e5 1122 TCPpacket();
nixnax 142:54d1543e23e5 1123 break;
nixnax 142:54d1543e23e5 1124 default:
nixnax 142:54d1543e23e5 1125 otherProtocol();
nixnax 142:54d1543e23e5 1126 }
nixnax 142:54d1543e23e5 1127 }
nixnax 142:54d1543e23e5 1128
nixnax 142:54d1543e23e5 1129 /// respond to LCP (line configuration protocol) configuration request) by allowing no options
nixnax 142:54d1543e23e5 1130 void LCPconfReq()
nixnax 142:54d1543e23e5 1131 {
nixnax 142:54d1543e23e5 1132 debugPrintf("LCP Config ");
nixnax 175:b4e6f8a6fe00 1133 if ( ppp.lcp->lengthR != __REV16(4) ) {
nixnax 175:b4e6f8a6fe00 1134 ppp.lcp->code=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 142:54d1543e23e5 1135 debugPrintf("Reject\n");
nixnax 144:01d98cf7738e 1136 sendPppFrame();
nixnax 142:54d1543e23e5 1137 } else {
nixnax 175:b4e6f8a6fe00 1138 ppp.lcp->code=2; // ack zero conf
nixnax 142:54d1543e23e5 1139 debugPrintf("Ack\n");
nixnax 144:01d98cf7738e 1140 sendPppFrame();
nixnax 142:54d1543e23e5 1141 debugPrintf("LCP Ask\n");
nixnax 175:b4e6f8a6fe00 1142 ppp.lcp->code=1; // request no options
nixnax 144:01d98cf7738e 1143 sendPppFrame();
nixnax 142:54d1543e23e5 1144 }
nixnax 142:54d1543e23e5 1145 }
nixnax 142:54d1543e23e5 1146
nixnax 142:54d1543e23e5 1147 /// handle LCP acknowledge packets by ignoring them
nixnax 142:54d1543e23e5 1148 void LCPconfAck()
nixnax 142:54d1543e23e5 1149 {
nixnax 142:54d1543e23e5 1150 debugPrintf("LCP Ack\n");
nixnax 142:54d1543e23e5 1151 }
nixnax 142:54d1543e23e5 1152
nixnax 143:c5019f856a56 1153 /// handle LCP end (disconnect) packets by acknowledging them and by setting ppp.online to false
nixnax 142:54d1543e23e5 1154 void LCPend()
nixnax 142:54d1543e23e5 1155 {
nixnax 175:b4e6f8a6fe00 1156 ppp.lcp->code=6; // end
nixnax 144:01d98cf7738e 1157 sendPppFrame(); // acknowledge
nixnax 142:54d1543e23e5 1158 ppp.online=0; // start hunting for connect string again
nixnax 142:54d1543e23e5 1159 pppInitStruct(); // flush the receive buffer
nixnax 143:c5019f856a56 1160 debugPrintf("LCP End (Disconnect from host)\n");
nixnax 142:54d1543e23e5 1161 }
nixnax 142:54d1543e23e5 1162
nixnax 142:54d1543e23e5 1163 /// respond to other LCP requests by ignoring them
nixnax 142:54d1543e23e5 1164 void LCPother()
nixnax 142:54d1543e23e5 1165 {
nixnax 142:54d1543e23e5 1166 debugPrintf("LCP Other\n");
nixnax 142:54d1543e23e5 1167 dumpPPPFrame();
nixnax 142:54d1543e23e5 1168 }
nixnax 142:54d1543e23e5 1169
nixnax 142:54d1543e23e5 1170 /// process incoming LCP packets
nixnax 142:54d1543e23e5 1171 void LCPframe()
nixnax 142:54d1543e23e5 1172 {
nixnax 175:b4e6f8a6fe00 1173 int code = ppp.lcp->code;
nixnax 142:54d1543e23e5 1174 switch (code) {
nixnax 142:54d1543e23e5 1175 case 1:
nixnax 142:54d1543e23e5 1176 LCPconfReq();
nixnax 142:54d1543e23e5 1177 break; // config request
nixnax 142:54d1543e23e5 1178 case 2:
nixnax 142:54d1543e23e5 1179 LCPconfAck();
nixnax 142:54d1543e23e5 1180 break; // config ack
nixnax 142:54d1543e23e5 1181 case 5:
nixnax 142:54d1543e23e5 1182 LCPend();
nixnax 142:54d1543e23e5 1183 break; // end connection
nixnax 142:54d1543e23e5 1184 default:
nixnax 142:54d1543e23e5 1185 LCPother();
nixnax 142:54d1543e23e5 1186 }
nixnax 142:54d1543e23e5 1187 }
nixnax 142:54d1543e23e5 1188
nixnax 142:54d1543e23e5 1189 /// discard packets that are not IP, IPCP, or LCP
nixnax 142:54d1543e23e5 1190 void discardedFrame()
nixnax 142:54d1543e23e5 1191 {
nixnax 142:54d1543e23e5 1192 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 1193 }
nixnax 142:54d1543e23e5 1194
nixnax 142:54d1543e23e5 1195 /// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax 142:54d1543e23e5 1196 void determinePacketType()
nixnax 142:54d1543e23e5 1197 {
nixnax 167:ff8a2d8beeb1 1198 if ( ppp.ppp->address != 0xff ) {
nixnax 167:ff8a2d8beeb1 1199 debugPrintf("Unexpected: PPP address != ff\n");
nixnax 142:54d1543e23e5 1200 return;
nixnax 142:54d1543e23e5 1201 }
nixnax 167:ff8a2d8beeb1 1202 if ( ppp.ppp->control != 3 ) {
nixnax 167:ff8a2d8beeb1 1203 debugPrintf("Unexpected: PPP control != 3\n");
nixnax 142:54d1543e23e5 1204 return;
nixnax 142:54d1543e23e5 1205 }
nixnax 167:ff8a2d8beeb1 1206 unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax 167:ff8a2d8beeb1 1207 switch ( protocol ) {
nixnax 167:ff8a2d8beeb1 1208 case 0xc021:
nixnax 142:54d1543e23e5 1209 LCPframe();
nixnax 142:54d1543e23e5 1210 break; // link control
nixnax 167:ff8a2d8beeb1 1211 case 0x8021:
nixnax 142:54d1543e23e5 1212 IPCPframe();
nixnax 142:54d1543e23e5 1213 break; // IP control
nixnax 167:ff8a2d8beeb1 1214 case 0x0021:
nixnax 142:54d1543e23e5 1215 IPframe();
nixnax 142:54d1543e23e5 1216 break; // IP itself
nixnax 142:54d1543e23e5 1217 default:
nixnax 142:54d1543e23e5 1218 discardedFrame();
nixnax 142:54d1543e23e5 1219 }
nixnax 142:54d1543e23e5 1220 }
nixnax 142:54d1543e23e5 1221
nixnax 146:a45f49a2b29c 1222 /// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 146:a45f49a2b29c 1223 void sniff()
nixnax 146:a45f49a2b29c 1224 {
nixnax 146:a45f49a2b29c 1225 if ( pc.readable() ) putsWhileCheckingInput( "Sniff - Char available!\n" ); // if this prints anything it means there is a character in the serial receive buffer
nixnax 146:a45f49a2b29c 1226 }
nixnax 146:a45f49a2b29c 1227
nixnax 142:54d1543e23e5 1228 /// scan the PPP serial input stream for frame start markers
nixnax 143:c5019f856a56 1229 void waitForPppFrame()
nixnax 142:54d1543e23e5 1230 {
nixnax 142:54d1543e23e5 1231 while(1) {
nixnax 182:f039ec218c9f 1232 sendUdpData(); // handle received characters from the DEBUG TERMINAL
nixnax 142:54d1543e23e5 1233 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 142:54d1543e23e5 1234 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 142:54d1543e23e5 1235 int rx = pc_getBuf(); // get the character
nixnax 142:54d1543e23e5 1236 if (rx==FRAME_7E) {
nixnax 142:54d1543e23e5 1237 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 142:54d1543e23e5 1238 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1239 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 181:bcfe7fe2142d 1240 ppp.firstFrame=0; // clear first frame flag
nixnax 142:54d1543e23e5 1241 } else {
nixnax 142:54d1543e23e5 1242 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 142:54d1543e23e5 1243 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 142:54d1543e23e5 1244 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1245 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax 142:54d1543e23e5 1246 break;
nixnax 142:54d1543e23e5 1247 }
nixnax 142:54d1543e23e5 1248 }
nixnax 142:54d1543e23e5 1249 }
nixnax 142:54d1543e23e5 1250 }
nixnax 142:54d1543e23e5 1251 }
nixnax 142:54d1543e23e5 1252
nixnax 153:7993def8663f 1253 /// Wait for a dial-up modem connect command ("CLIENT") from the host PC, if found, we set ppp.online to true, which will start the IP packet scanner.
nixnax 153:7993def8663f 1254 // Note: a 0x7E in the input stream (ppp start of frame character) will also set ppp.online to true - see checkPc();
nixnax 153:7993def8663f 1255 void waitForPcConnectString()
nixnax 142:54d1543e23e5 1256 {
nixnax 142:54d1543e23e5 1257 while(ppp.online == 0) {
nixnax 142:54d1543e23e5 1258 checkPc(); // gather received characters
nixnax 142:54d1543e23e5 1259 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 142:54d1543e23e5 1260 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 142:54d1543e23e5 1261 if (found1 != NULL) {
nixnax 142:54d1543e23e5 1262 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 143:c5019f856a56 1263 if (v0) debugPrintf("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 142:54d1543e23e5 1264 pc.puts("CLIENTSERVER");
nixnax 142:54d1543e23e5 1265 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 142:54d1543e23e5 1266 checkPc();
nixnax 142:54d1543e23e5 1267 }
nixnax 142:54d1543e23e5 1268 }
nixnax 142:54d1543e23e5 1269 }
nixnax 142:54d1543e23e5 1270
nixnax 144:01d98cf7738e 1271 /// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax 144:01d98cf7738e 1272 void initializePpp()
nixnax 142:54d1543e23e5 1273 {
nixnax 144:01d98cf7738e 1274 debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax 184:4133f557d4d4 1275 debugPrintf("\x1b[2J\x1b[H\x1b[30m");
nixnax 184:4133f557d4d4 1276 wait_ms(200); // a brief wait so a human can see the reset event
nixnax 184:4133f557d4d4 1277 debugPrintf("mbed PPP-Blinky HTTP & WebSocket server ready :)\n"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
nixnax 184:4133f557d4d4 1278
nixnax 179:ba2b2ddd0da5 1279 pppInitStruct(); // initialize all the variables/properties/buffers
nixnax 179:ba2b2ddd0da5 1280 pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
nixnax 179:ba2b2ddd0da5 1281 pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
nixnax 143:c5019f856a56 1282 }