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@196:8791e241be80, 2017-12-06 (annotated)

Committer:
nixnax
Date:
Wed Dec 06 22:51:23 2017 +0000
Revision:
196:8791e241be80
Parent:
194:5b23ebfb3626
Child:
201:9fcf92e9f427
Added Nucleo-L432KC board as a target.; Note - Nucleo-L432KC currently works only with Revision 152 of mbed library. Revision 152 is used in this commit.

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 142:54d1543e23e5 12 // Handy reading material
nixnax 142:54d1543e23e5 13 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 142:54d1543e23e5 14 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 142:54d1543e23e5 15 // http://atari.kensclassics.org/wcomlog.htm
nixnax 142:54d1543e23e5 16
nixnax 142:54d1543e23e5 17 // Handy tools
nixnax 142:54d1543e23e5 18 // https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax 142:54d1543e23e5 19 // https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax 142:54d1543e23e5 20 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 142:54d1543e23e5 21 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE), then custom relected-in=1, reflected-out=1
nixnax 142:54d1543e23e5 22 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 142:54d1543e23e5 23 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 142:54d1543e23e5 24 // Windows Powershell invoke-webrequest command - use it to stress test the webserver like this: while (1){ invoke-webrequest -uri 172.10.10.1/x }
nixnax 142:54d1543e23e5 25
nixnax 142:54d1543e23e5 26 // Connecting PPP-Blinky to Linux
nixnax 142:54d1543e23e5 27 // PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax 142:54d1543e23e5 28 // pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax 142:54d1543e23e5 29 // in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax 142:54d1543e23e5 30 // See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax 142:54d1543e23e5 31
nixnax 142:54d1543e23e5 32 // Special pages when PPP-Blinky is running
nixnax 142:54d1543e23e5 33 // 172.10.10.2 root page
nixnax 182:f039ec218c9f 34 // 172.10.10.2/x returns the number of ppp frames sent - this is handy for testing
nixnax 182:f039ec218c9f 35 // 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 36 // 172.10.10.2/ws a simple WebSocket demo
nixnax 182:f039ec218c9f 37 // http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle, showing cross-domain access
nixnax 142:54d1543e23e5 38
nixnax 142:54d1543e23e5 39 // Ok, enough talking, time to check out some code!!
nixnax 142:54d1543e23e5 40
nixnax 142:54d1543e23e5 41 #include "ppp-blinky.h"
nixnax 142:54d1543e23e5 42
nixnax 142:54d1543e23e5 43 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax 146:a45f49a2b29c 44 // Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor the debug output.
nixnax 142:54d1543e23e5 45 // Using the second serial port will slow down packet response time
nixnax 142:54d1543e23e5 46 // Note - the LPC11U24 does NOT have a second serial port
nixnax 146:a45f49a2b29c 47
nixnax 183:6d3ba874b267 48 #define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax 142:54d1543e23e5 49
nixnax 142:54d1543e23e5 50 // here we define the OPTIONAL, second debug serial port for various mbed target boards
nixnax 142:54d1543e23e5 51 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 52 #if defined(TARGET_LPC1768)
nixnax 179:ba2b2ddd0da5 53 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 54 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
nixnax 179:ba2b2ddd0da5 55 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 56 #elif defined(TARGET_NUCLEO_L432KC)
nixnax 196:8791e241be80 57 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 58 #elif defined(TARGET_LPC11U24)
nixnax 142:54d1543e23e5 59 #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 60 #elif defined (TARGET_KL46Z) || (TARGET_KL25Z)
nixnax 179:ba2b2ddd0da5 61 RawSerial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax 193:48072570f41d 62 #elif defined(TARGET_KW41Z)
nixnax 194:5b23ebfb3626 63 RawSerial xx(PTC3, PTC2); // Second serial port on FRDM-KW41Z board
nixnax 142:54d1543e23e5 64 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 142:54d1543e23e5 65 // 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 66 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 67 #else
nixnax 142:54d1543e23e5 68 #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 69 #endif
nixnax 179:ba2b2ddd0da5 70 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we can print debug messages */
nixnax 142:54d1543e23e5 71 #define debugPutc(x...) xx.putc(x)
nixnax 142:54d1543e23e5 72 #define debugBaudRate(x...) xx.baud(x)
nixnax 142:54d1543e23e5 73 #else
nixnax 142:54d1543e23e5 74 // if we don't have a debug port the debug print functions do nothing
nixnax 142:54d1543e23e5 75 #define debugPrintf(x...) {}
nixnax 142:54d1543e23e5 76 #define debugPutc(x...) {}
nixnax 142:54d1543e23e5 77 #define debugBaudRate(x...) {}
nixnax 142:54d1543e23e5 78 #endif
nixnax 142:54d1543e23e5 79
nixnax 142:54d1543e23e5 80 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 182:f039ec218c9f 81 #define v0 1
nixnax 142:54d1543e23e5 82 #define v1 0
nixnax 142:54d1543e23e5 83 #define v2 0
nixnax 182:f039ec218c9f 84 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 182:f039ec218c9f 85 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 142:54d1543e23e5 86
nixnax 142:54d1543e23e5 87 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 142:54d1543e23e5 88 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 142:54d1543e23e5 89
nixnax 142:54d1543e23e5 90 const static char rootWebPage[] = "\
nixnax 142:54d1543e23e5 91 <!DOCTYPE html>\
nixnax 142:54d1543e23e5 92 <html>\
nixnax 142:54d1543e23e5 93 <head>\
nixnax 146:a45f49a2b29c 94 <title>mbed PPP-Blinky</title>\r\n\
nixnax 146:a45f49a2b29c 95 <script>\r\n\
nixnax 142:54d1543e23e5 96 window.onload=function(){\
nixnax 142:54d1543e23e5 97 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 146:a45f49a2b29c 98 x().textContent=parseInt(x().textContent)+1;},100);};\r\n\
nixnax 146:a45f49a2b29c 99 </script>\r\n\
nixnax 142:54d1543e23e5 100 </head>\
nixnax 142:54d1543e23e5 101 <body style=\"font-family: sans-serif; font-size:20px; text-align:center; color:#807070\">\
nixnax 142:54d1543e23e5 102 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 142:54d1543e23e5 103 <h1 id=\"w\">0</h1>\
nixnax 142:54d1543e23e5 104 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 142:54d1543e23e5 105 <h1><a href=\"/ws\">WebSocket Demo</a></h1>\
nixnax 142:54d1543e23e5 106 <h1><a href=\"/x\">Benchmark 1</a></h1>\
nixnax 142:54d1543e23e5 107 <h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax 142:54d1543e23e5 108 <h1><a href=\"http://jsfiddle.net/d26cyuh2/\">JSFiddle Demo</a></h1>\
nixnax 142:54d1543e23e5 109 </body>\
nixnax 146:a45f49a2b29c 110 </html>\r\n"; // size = 644 bytes plus 1 null byte = 645 bytes
nixnax 142:54d1543e23e5 111
nixnax 167:ff8a2d8beeb1 112 // this is a websocket demo html page we serve when GET /ws is requested
nixnax 142:54d1543e23e5 113 const static char webSocketPage[] = "\
nixnax 142:54d1543e23e5 114 <!DOCTYPE html>\
nixnax 142:54d1543e23e5 115 <html>\
nixnax 142:54d1543e23e5 116 <head>\
nixnax 142:54d1543e23e5 117 <title>mbed PPP-Blinky</title>\
nixnax 142:54d1543e23e5 118 <script>\
nixnax 142:54d1543e23e5 119 window.onload=function(){\
nixnax 142:54d1543e23e5 120 var url=\"ws://172.10.10.2\";\
nixnax 142:54d1543e23e5 121 var sts=document.getElementById(\"sts\");\
nixnax 142:54d1543e23e5 122 var btn=document.getElementById(\"btn\");\
nixnax 142:54d1543e23e5 123 var ctr=0;\
nixnax 142:54d1543e23e5 124 function show(text){sts.textContent=text;}\
nixnax 142:54d1543e23e5 125 btn.onclick=function(){\
nixnax 142:54d1543e23e5 126 if(btn.textContent==\"Connect\"){\
nixnax 142:54d1543e23e5 127 x=new WebSocket(url);\
nixnax 142:54d1543e23e5 128 x.onopen=function(){\
nixnax 142:54d1543e23e5 129 show(\"Connected to : \"+url);\
nixnax 142:54d1543e23e5 130 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 142:54d1543e23e5 131 };\
nixnax 142:54d1543e23e5 132 x.onclose=function(){show(\"closed\");};\
nixnax 142:54d1543e23e5 133 x.onmessage=function(msg){show(\"PPP-Blinky Sent: \\\"\"+msg.data+\"\\\"\");};\
nixnax 142:54d1543e23e5 134 } else {\
nixnax 142:54d1543e23e5 135 x.send(ctr);\
nixnax 142:54d1543e23e5 136 ctr=ctr+1;\
nixnax 142:54d1543e23e5 137 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 142:54d1543e23e5 138 }\
nixnax 142:54d1543e23e5 139 };\
nixnax 142:54d1543e23e5 140 };\
nixnax 142:54d1543e23e5 141 </script>\
nixnax 142:54d1543e23e5 142 <body style=\"font-family: sans-serif; font-size:25px; color:#807070\">\
nixnax 142:54d1543e23e5 143 <h1>PPP-Blinky WebSocket Test</h1>\
nixnax 142:54d1543e23e5 144 <div id=\"sts\">Idle</div>\
nixnax 142:54d1543e23e5 145 <button id=\"btn\" style=\"font-size: 100%; margin-top: 55px; margin-bottom: 55px;\">Connect</button>\
nixnax 142:54d1543e23e5 146 <h4><a href=\"/\">PPP-Blinky home</a></h4>\
nixnax 142:54d1543e23e5 147 </body>\
nixnax 142:54d1543e23e5 148 </html>"; // size = 916 bytes + 1 null byte = 917 bytes
nixnax 142:54d1543e23e5 149
nixnax 142:54d1543e23e5 150 // 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 151 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 142:54d1543e23e5 152 // The modem baud rate should be set to 115200 baud
nixnax 142:54d1543e23e5 153 // See instructions at the top.
nixnax 142:54d1543e23e5 154 // 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 155 RawSerial pc (USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax 142:54d1543e23e5 156
nixnax 142:54d1543e23e5 157 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 142:54d1543e23e5 158
nixnax 142:54d1543e23e5 159 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 142:54d1543e23e5 160 #define FRAME_7E (0x7e)
nixnax 142:54d1543e23e5 161
nixnax 142:54d1543e23e5 162 pppType ppp; // our global - definitely not thread safe
nixnax 142:54d1543e23e5 163
nixnax 142:54d1543e23e5 164 /// Initialize the ppp structure and clear the receive buffer
nixnax 142:54d1543e23e5 165 void pppInitStruct()
nixnax 142:54d1543e23e5 166 {
nixnax 142:54d1543e23e5 167 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 142:54d1543e23e5 168 ppp.online=0;
nixnax 142:54d1543e23e5 169 ppp.rx.tail=0;
nixnax 142:54d1543e23e5 170 ppp.rx.rtail=0;
nixnax 142:54d1543e23e5 171 ppp.rx.head=0;
nixnax 142:54d1543e23e5 172 ppp.rx.buflevel=0;
nixnax 142:54d1543e23e5 173 ppp.pkt.len=0;
nixnax 154:18b2bd92f557 174 ppp.ipData.ident=10000; // easy to recognize in ip packet dumps
nixnax 142:54d1543e23e5 175 ppp.ledState=0;
nixnax 142:54d1543e23e5 176 ppp.hdlc.frameStartIndex=0;
nixnax 146:a45f49a2b29c 177 ppp.responseCounter=0;
nixnax 142:54d1543e23e5 178 ppp.firstFrame=1;
nixnax 175:b4e6f8a6fe00 179 ppp.ppp = (pppHeaderType *)ppp.pkt.buf; // pointer to ppp header
nixnax 175:b4e6f8a6fe00 180 ppp.ip = (ipHeaderType *)(ppp.pkt.buf+4); // pointer to IP header
nixnax 142:54d1543e23e5 181 }
nixnax 142:54d1543e23e5 182
nixnax 142:54d1543e23e5 183 /// Toggle the LED on every second PPP packet received
nixnax 142:54d1543e23e5 184 void led1Toggle()
nixnax 142:54d1543e23e5 185 {
nixnax 142:54d1543e23e5 186 led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax 143:c5019f856a56 187 ppp.ledState++;
nixnax 142:54d1543e23e5 188 }
nixnax 142:54d1543e23e5 189
nixnax 179:ba2b2ddd0da5 190 /// Returns 1 after a connect message, 0 at startup or after a disconnect message
nixnax 150:3366bf3d294e 191 int connectedPpp()
nixnax 142:54d1543e23e5 192 {
nixnax 142:54d1543e23e5 193 return ppp.online;
nixnax 143:c5019f856a56 194 }
nixnax 142:54d1543e23e5 195
nixnax 179:ba2b2ddd0da5 196 /// Previously used to check for characters in receive buffer.
nixnax 179:ba2b2ddd0da5 197 /// Now just a stub.
nixnax 179:ba2b2ddd0da5 198 void checkPc() {};
nixnax 179:ba2b2ddd0da5 199
nixnax 179:ba2b2ddd0da5 200 /// PPP serial port receive interrupt handler.
nixnax 143:c5019f856a56 201 /// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax 143:c5019f856a56 202 /// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax 179:ba2b2ddd0da5 203 void pppReceiveHandler()
nixnax 142:54d1543e23e5 204 {
nixnax 142:54d1543e23e5 205 char ch;
nixnax 179:ba2b2ddd0da5 206 while ( pc.readable() ) {
nixnax 142:54d1543e23e5 207 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 142:54d1543e23e5 208 if ( hd == ppp.rx.rtail ) {
nixnax 142:54d1543e23e5 209 debugPrintf("\nReceive buffer full\n");
nixnax 142:54d1543e23e5 210 return;
nixnax 142:54d1543e23e5 211 }
nixnax 142:54d1543e23e5 212 ch = pc.getc(); // read new character
nixnax 142:54d1543e23e5 213 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 142:54d1543e23e5 214 if ( ppp.online == 0 ) {
nixnax 142:54d1543e23e5 215 if (ch == 0x7E) {
nixnax 142:54d1543e23e5 216 ppp.online = 1;
nixnax 142:54d1543e23e5 217 }
nixnax 142:54d1543e23e5 218 }
nixnax 142:54d1543e23e5 219 ppp.rx.head = hd; // update head pointer
nixnax 142:54d1543e23e5 220 ppp.rx.buflevel++;
nixnax 142:54d1543e23e5 221 }
nixnax 142:54d1543e23e5 222 }
nixnax 142:54d1543e23e5 223
nixnax 142:54d1543e23e5 224 /// print to debug port while checking for incoming characters
nixnax 142:54d1543e23e5 225 void putcWhileCheckingInput( char outByte )
nixnax 142:54d1543e23e5 226 {
nixnax 142:54d1543e23e5 227 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 228 checkPc();
nixnax 142:54d1543e23e5 229 debugPutc( outByte );
nixnax 142:54d1543e23e5 230 checkPc();
nixnax 142:54d1543e23e5 231 #endif
nixnax 142:54d1543e23e5 232 }
nixnax 142:54d1543e23e5 233
nixnax 142:54d1543e23e5 234 /// puts to debug port while checking the PPP input stream
nixnax 142:54d1543e23e5 235 void putsWhileCheckingInput( char * data )
nixnax 142:54d1543e23e5 236 {
nixnax 142:54d1543e23e5 237 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 238 char * nextChar = data;
nixnax 142:54d1543e23e5 239 while( *nextChar != 0 ) {
nixnax 142:54d1543e23e5 240 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 142:54d1543e23e5 241 nextChar++;
nixnax 142:54d1543e23e5 242 }
nixnax 142:54d1543e23e5 243 #endif
nixnax 142:54d1543e23e5 244 }
nixnax 142:54d1543e23e5 245
nixnax 145:098b6ed2f7f2 246 /// Initialize the PPP FCS (frame check sequence) total
nixnax 145:098b6ed2f7f2 247 void fcsReset()
nixnax 142:54d1543e23e5 248 {
nixnax 145:098b6ed2f7f2 249 ppp.fcs=0xffff; // crc restart
nixnax 142:54d1543e23e5 250 }
nixnax 142:54d1543e23e5 251
nixnax 145:098b6ed2f7f2 252 /// update the cumulative PPP FCS (frame check sequence)
nixnax 145:098b6ed2f7f2 253 void fcsDo(int x)
nixnax 142:54d1543e23e5 254 {
nixnax 142:54d1543e23e5 255 for (int i=0; i<8; i++) {
nixnax 145:098b6ed2f7f2 256 ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1; // crc calculator
nixnax 142:54d1543e23e5 257 x>>=1;
nixnax 142:54d1543e23e5 258 }
nixnax 142:54d1543e23e5 259 checkPc(); // handle input
nixnax 142:54d1543e23e5 260 }
nixnax 142:54d1543e23e5 261
nixnax 145:098b6ed2f7f2 262 /// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax 145:098b6ed2f7f2 263 int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax 142:54d1543e23e5 264 {
nixnax 145:098b6ed2f7f2 265 fcsReset();
nixnax 145:098b6ed2f7f2 266 for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax 145:098b6ed2f7f2 267 return ppp.fcs;
nixnax 142:54d1543e23e5 268 }
nixnax 142:54d1543e23e5 269
nixnax 142:54d1543e23e5 270 /// Get one character from our received PPP buffer
nixnax 142:54d1543e23e5 271 int pc_getBuf()
nixnax 142:54d1543e23e5 272 {
nixnax 142:54d1543e23e5 273 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 142:54d1543e23e5 274 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 142:54d1543e23e5 275 ppp.rx.buflevel--;
nixnax 142:54d1543e23e5 276 return x;
nixnax 142:54d1543e23e5 277 }
nixnax 142:54d1543e23e5 278
nixnax 142:54d1543e23e5 279 /// Dump a PPP frame to the debug serial port
nixnax 142:54d1543e23e5 280 /// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 142:54d1543e23e5 281 /// Capture the frame's hex output in your terminal program and save as a text file
nixnax 164:c3de3d212c4b 282 /// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax 142:54d1543e23e5 283 void dumpPPPFrame()
nixnax 142:54d1543e23e5 284 {
nixnax 142:54d1543e23e5 285 char pbuf[30];
nixnax 142:54d1543e23e5 286 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 287 checkPc();
nixnax 142:54d1543e23e5 288 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 142:54d1543e23e5 289 checkPc();
nixnax 142:54d1543e23e5 290 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 291 }
nixnax 142:54d1543e23e5 292 checkPc();
nixnax 142:54d1543e23e5 293 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 142:54d1543e23e5 294 checkPc();
nixnax 142:54d1543e23e5 295 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 296 }
nixnax 142:54d1543e23e5 297
nixnax 142:54d1543e23e5 298 /// Process a received PPP frame
nixnax 142:54d1543e23e5 299 void processPPPFrame(int start, int end)
nixnax 142:54d1543e23e5 300 {
nixnax 142:54d1543e23e5 301 led1Toggle(); // change led1 state on every frame we receive
nixnax 142:54d1543e23e5 302 if(start==end) {
nixnax 142:54d1543e23e5 303 return; // empty frame
nixnax 142:54d1543e23e5 304 }
nixnax 145:098b6ed2f7f2 305 fcsReset();
nixnax 142:54d1543e23e5 306 char * dest = ppp.pkt.buf;
nixnax 142:54d1543e23e5 307 ppp.pkt.len=0;
nixnax 142:54d1543e23e5 308 int unstuff=0;
nixnax 142:54d1543e23e5 309 int idx = start;
nixnax 142:54d1543e23e5 310 while(1) {
nixnax 142:54d1543e23e5 311 checkPc();
nixnax 142:54d1543e23e5 312 if (unstuff==0) {
nixnax 142:54d1543e23e5 313 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 142:54d1543e23e5 314 else {
nixnax 142:54d1543e23e5 315 *dest = ppp.rx.buf[idx];
nixnax 142:54d1543e23e5 316 ppp.pkt.len++;
nixnax 142:54d1543e23e5 317 dest++;
nixnax 145:098b6ed2f7f2 318 fcsDo(ppp.rx.buf[idx]);
nixnax 142:54d1543e23e5 319 }
nixnax 142:54d1543e23e5 320 } else { // unstuff characters prefixed with 0x7d
nixnax 142:54d1543e23e5 321 *dest = ppp.rx.buf[idx]^0x20;
nixnax 142:54d1543e23e5 322 ppp.pkt.len++;
nixnax 142:54d1543e23e5 323 dest++;
nixnax 145:098b6ed2f7f2 324 fcsDo(ppp.rx.buf[idx]^0x20);
nixnax 142:54d1543e23e5 325 unstuff=0;
nixnax 142:54d1543e23e5 326 }
nixnax 142:54d1543e23e5 327 idx = (idx+1) & (RXBUFLEN-1);
nixnax 142:54d1543e23e5 328 if (idx == end) break;
nixnax 142:54d1543e23e5 329 }
nixnax 145:098b6ed2f7f2 330 ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax 142:54d1543e23e5 331 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 142:54d1543e23e5 332 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 142:54d1543e23e5 333 determinePacketType();
nixnax 142:54d1543e23e5 334 } else {
nixnax 142:54d1543e23e5 335 #define REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 336 #ifdef REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 337 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 338 checkPc();
nixnax 142:54d1543e23e5 339 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 142:54d1543e23e5 340 checkPc();
nixnax 142:54d1543e23e5 341 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 342 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 142:54d1543e23e5 343 #endif
nixnax 142:54d1543e23e5 344 }
nixnax 142:54d1543e23e5 345 }
nixnax 142:54d1543e23e5 346
nixnax 142:54d1543e23e5 347 /// output a character to the PPP port while checking for incoming characters
nixnax 142:54d1543e23e5 348 void pcPutcWhileCheckingInput(int ch)
nixnax 142:54d1543e23e5 349 {
nixnax 142:54d1543e23e5 350 checkPc(); // check input
nixnax 142:54d1543e23e5 351 pc.putc(ch);
nixnax 142:54d1543e23e5 352 checkPc();
nixnax 142:54d1543e23e5 353 }
nixnax 142:54d1543e23e5 354
nixnax 142:54d1543e23e5 355 /// do PPP HDLC-like handling of special (flag) characters
nixnax 143:c5019f856a56 356 void hdlcPut(int ch)
nixnax 142:54d1543e23e5 357 {
nixnax 142:54d1543e23e5 358 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 142:54d1543e23e5 359 pcPutcWhileCheckingInput(0x7d);
nixnax 142:54d1543e23e5 360 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 142:54d1543e23e5 361 } else {
nixnax 142:54d1543e23e5 362 pcPutcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 363 }
nixnax 142:54d1543e23e5 364 }
nixnax 142:54d1543e23e5 365
nixnax 142:54d1543e23e5 366 /// send a PPP frame in HDLC format
nixnax 144:01d98cf7738e 367 void sendPppFrame()
nixnax 143:c5019f856a56 368 {
nixnax 172:449dd7a28955 369 ppp.responseCounter++; // count the number of ppp frames we send
nixnax 145:098b6ed2f7f2 370 int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 142:54d1543e23e5 371 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 142:54d1543e23e5 372 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 142:54d1543e23e5 373 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 142:54d1543e23e5 374 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 375 wait_us(86); // wait one character time
nixnax 142:54d1543e23e5 376 checkPc();
nixnax 142:54d1543e23e5 377 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 142:54d1543e23e5 378 }
nixnax 142:54d1543e23e5 379 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 142:54d1543e23e5 380 }
nixnax 142:54d1543e23e5 381
nixnax 143:c5019f856a56 382 /// 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 383 int bufferToIP(char * buffer)
nixnax 143:c5019f856a56 384 {
nixnax 143:c5019f856a56 385 int result=0;
nixnax 143:c5019f856a56 386 for(int i=0; i<4; i++) result = (result<<8)|(*buffer++ & 0xff);
nixnax 143:c5019f856a56 387 return result;
nixnax 143:c5019f856a56 388 }
nixnax 143:c5019f856a56 389
nixnax 177:dab9e685af53 390 /// convert 4-byte ip address to 32-bit
nixnax 179:ba2b2ddd0da5 391 unsigned int ip( int a, int b, int c, int d)
nixnax 179:ba2b2ddd0da5 392 {
nixnax 177:dab9e685af53 393 return a<<24 | b<<16 | c<<8 | d;
nixnax 177:dab9e685af53 394 }
nixnax 177:dab9e685af53 395
nixnax 142:54d1543e23e5 396 /// handle IPCP configuration requests
nixnax 142:54d1543e23e5 397 void ipcpConfigRequestHandler()
nixnax 142:54d1543e23e5 398 {
nixnax 142:54d1543e23e5 399 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 173:6774a0c851c4 400 if(ppp.ipcp->request[0]==3) {
nixnax 143:c5019f856a56 401 ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax 173:6774a0c851c4 402 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 403 }
nixnax 143:c5019f856a56 404
nixnax 167:ff8a2d8beeb1 405 ppp.ipcp->code=2; // change code to ack
nixnax 144:01d98cf7738e 406 sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 142:54d1543e23e5 407
nixnax 142:54d1543e23e5 408 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 167:ff8a2d8beeb1 409 ppp.ipcp->code=1; // change code to request
nixnax 167:ff8a2d8beeb1 410 ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax 167:ff8a2d8beeb1 411 ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 144:01d98cf7738e 412 sendPppFrame(); // send our request
nixnax 142:54d1543e23e5 413 }
nixnax 142:54d1543e23e5 414
nixnax 142:54d1543e23e5 415 /// handle IPCP acknowledge (do nothing)
nixnax 142:54d1543e23e5 416 void ipcpAckHandler()
nixnax 142:54d1543e23e5 417 {
nixnax 142:54d1543e23e5 418 debugPrintf("Their IPCP Grant\n");
nixnax 142:54d1543e23e5 419 }
nixnax 142:54d1543e23e5 420
nixnax 143:c5019f856a56 421 /// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax 143:c5019f856a56 422 /// 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 423 void ipcpNackHandler()
nixnax 142:54d1543e23e5 424 {
nixnax 146:a45f49a2b29c 425 debugPrintf("Their IPCP Nack\n");
nixnax 173:6774a0c851c4 426 if (ppp.ipcp->request[0]==3) { // check if the NACK contains an IP address parameter
nixnax 167:ff8a2d8beeb1 427 ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax 144:01d98cf7738e 428 sendPppFrame(); // let's request this IP address as ours
nixnax 143:c5019f856a56 429 debugPrintf("Our IPCP ACK (received an IP)\n");
nixnax 146:a45f49a2b29c 430 } else { // if it's not an IP nack we ignore it
nixnax 146:a45f49a2b29c 431 debugPrintf("IPCP Nack Ignored\n");
nixnax 146:a45f49a2b29c 432 }
nixnax 142:54d1543e23e5 433 }
nixnax 142:54d1543e23e5 434
nixnax 142:54d1543e23e5 435 /// handle all other IPCP requests (by ignoring them)
nixnax 142:54d1543e23e5 436 void ipcpDefaultHandler()
nixnax 142:54d1543e23e5 437 {
nixnax 142:54d1543e23e5 438 debugPrintf("Their IPCP Other\n");
nixnax 142:54d1543e23e5 439 }
nixnax 142:54d1543e23e5 440
nixnax 142:54d1543e23e5 441 /// process an incoming IPCP packet
nixnax 142:54d1543e23e5 442 void IPCPframe()
nixnax 142:54d1543e23e5 443 {
nixnax 167:ff8a2d8beeb1 444 int action = ppp.ipcp->code; // packet type is here
nixnax 167:ff8a2d8beeb1 445 switch (action) {
nixnax 142:54d1543e23e5 446 case 1:
nixnax 142:54d1543e23e5 447 ipcpConfigRequestHandler();
nixnax 142:54d1543e23e5 448 break;
nixnax 142:54d1543e23e5 449 case 2:
nixnax 142:54d1543e23e5 450 ipcpAckHandler();
nixnax 142:54d1543e23e5 451 break;
nixnax 142:54d1543e23e5 452 case 3:
nixnax 142:54d1543e23e5 453 ipcpNackHandler();
nixnax 142:54d1543e23e5 454 break;
nixnax 142:54d1543e23e5 455 default:
nixnax 142:54d1543e23e5 456 ipcpDefaultHandler();
nixnax 142:54d1543e23e5 457 }
nixnax 142:54d1543e23e5 458 }
nixnax 142:54d1543e23e5 459
nixnax 142:54d1543e23e5 460 /// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax 161:d59f778bc8ab 461 unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax 142:54d1543e23e5 462 {
nixnax 159:4d1bf96a59cd 463 unsigned int i,hi,lo;
nixnax 142:54d1543e23e5 464 unsigned char placeHolder;
nixnax 161:d59f778bc8ab 465 if (restart) ppp.sum=0;
nixnax 142:54d1543e23e5 466 if (len&1) {
nixnax 142:54d1543e23e5 467 placeHolder = ptr[len];
nixnax 142:54d1543e23e5 468 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 469 }
nixnax 142:54d1543e23e5 470 i=0;
nixnax 142:54d1543e23e5 471 while ( i<len ) {
nixnax 142:54d1543e23e5 472 checkPc();
nixnax 142:54d1543e23e5 473 hi = ptr[i++];
nixnax 142:54d1543e23e5 474 lo = ptr[i++];
nixnax 159:4d1bf96a59cd 475 ppp.sum = ppp.sum + ((hi<<8)|lo);
nixnax 142:54d1543e23e5 476 }
nixnax 142:54d1543e23e5 477 if (len&1) {
nixnax 142:54d1543e23e5 478 ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax 142:54d1543e23e5 479 }
nixnax 159:4d1bf96a59cd 480 ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax 159:4d1bf96a59cd 481 ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax 159:4d1bf96a59cd 482 return ~ppp.sum;
nixnax 142:54d1543e23e5 483 }
nixnax 142:54d1543e23e5 484
nixnax 142:54d1543e23e5 485 /// perform the checksum on an IP header
nixnax 146:a45f49a2b29c 486 void IpHeaderCheckSum()
nixnax 142:54d1543e23e5 487 {
nixnax 161:d59f778bc8ab 488 ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax 161:d59f778bc8ab 489 int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax 161:d59f778bc8ab 490 unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax 161:d59f778bc8ab 491 ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax 146:a45f49a2b29c 492 }
nixnax 146:a45f49a2b29c 493
nixnax 147:0f40005cbc5f 494 /// swap the IP source and destination addresses
nixnax 147:0f40005cbc5f 495 void swapIpAddresses()
nixnax 147:0f40005cbc5f 496 {
nixnax 162:594729c0e5c1 497 unsigned int tempHold;
nixnax 162:594729c0e5c1 498 tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax 162:594729c0e5c1 499 ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax 162:594729c0e5c1 500 ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax 147:0f40005cbc5f 501 }
nixnax 147:0f40005cbc5f 502
nixnax 149:969d98f6fb88 503 /// swap the IP source and destination ports
nixnax 149:969d98f6fb88 504 void swapIpPorts()
nixnax 149:969d98f6fb88 505 {
nixnax 173:6774a0c851c4 506 int headerSizeIP = 4 * (ppp.ip->headerLength); // calculate size of IP header
nixnax 173:6774a0c851c4 507 char * ipSrcPort = ppp.ipStart + headerSizeIP + 0; // ip source port location
nixnax 173:6774a0c851c4 508 char * ipDstPort = ppp.ipStart + headerSizeIP + 2; // ip destin port location
nixnax 149:969d98f6fb88 509 char tempHold[2];
nixnax 149:969d98f6fb88 510 memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax 149:969d98f6fb88 511 memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax 149:969d98f6fb88 512 memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax 149:969d98f6fb88 513 }
nixnax 149:969d98f6fb88 514
nixnax 170:3d3b2126181c 515 /// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax 170:3d3b2126181c 516 void checkSumPseudoHeader( unsigned int packetLength )
nixnax 170:3d3b2126181c 517 {
nixnax 170:3d3b2126181c 518 // 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 519 pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax 170:3d3b2126181c 520 pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax 170:3d3b2126181c 521 pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax 170:3d3b2126181c 522 pseudoHeader.zero = 0; // zero byte
nixnax 170:3d3b2126181c 523 pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax 170:3d3b2126181c 524 pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax 170:3d3b2126181c 525 dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax 170:3d3b2126181c 526 }
nixnax 170:3d3b2126181c 527
nixnax 171:46b36d4edd1d 528 /// initialize an IP packet to send
nixnax 171:46b36d4edd1d 529 void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax 171:46b36d4edd1d 530 {
nixnax 171:46b36d4edd1d 531 ppp.ppp->address = 0xff;
nixnax 171:46b36d4edd1d 532 ppp.ppp->control = 3;
nixnax 171:46b36d4edd1d 533 ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax 171:46b36d4edd1d 534 ppp.ip->version = 4;
nixnax 171:46b36d4edd1d 535 ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax 171:46b36d4edd1d 536 ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax 171:46b36d4edd1d 537 ppp.ip->dontFragment=1;
nixnax 171:46b36d4edd1d 538 ppp.ip->ttl=128;
nixnax 171:46b36d4edd1d 539 ppp.ip->protocol = protocol; // udp
nixnax 171:46b36d4edd1d 540 ppp.ip->srcAdrR = __REV(srcIp);
nixnax 171:46b36d4edd1d 541 ppp.ip->dstAdrR = __REV(dstIp);
nixnax 171:46b36d4edd1d 542 ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax 171:46b36d4edd1d 543 ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax 171:46b36d4edd1d 544 ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax 171:46b36d4edd1d 545 }
nixnax 171:46b36d4edd1d 546
nixnax 171:46b36d4edd1d 547
nixnax 171:46b36d4edd1d 548 /// Build a UDP packet from scratch
nixnax 171:46b36d4edd1d 549 void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax 171:46b36d4edd1d 550 {
nixnax 171:46b36d4edd1d 551 struct {
nixnax 171:46b36d4edd1d 552 unsigned int ipAll; // length of entire ip packet
nixnax 171:46b36d4edd1d 553 unsigned int ipHeader; // length of ip header
nixnax 171:46b36d4edd1d 554 unsigned int udpAll; // length of entire udp packet
nixnax 171:46b36d4edd1d 555 unsigned int udpData; // length of udp data segment
nixnax 171:46b36d4edd1d 556 } len;
nixnax 171:46b36d4edd1d 557 len.ipHeader = 20; // ip header length
nixnax 171:46b36d4edd1d 558 len.udpData = msgLen; // udp data size
nixnax 171:46b36d4edd1d 559 len.udpAll = len.udpData+8; // update local udp packet length
nixnax 171:46b36d4edd1d 560 len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax 171:46b36d4edd1d 561 initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax 171:46b36d4edd1d 562 ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax 171:46b36d4edd1d 563 ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax 171:46b36d4edd1d 564 memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax 171:46b36d4edd1d 565 ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax 171:46b36d4edd1d 566 ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax 171:46b36d4edd1d 567 IpHeaderCheckSum(); // refresh IP header checksum
nixnax 171:46b36d4edd1d 568 checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax 171:46b36d4edd1d 569 ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 171:46b36d4edd1d 570 unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax 171:46b36d4edd1d 571 ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 171:46b36d4edd1d 572 sendPppFrame(); // send the UDP message back
nixnax 171:46b36d4edd1d 573 }
nixnax 171:46b36d4edd1d 574
nixnax 146:a45f49a2b29c 575 /// Process an incoming UDP packet.
nixnax 146:a45f49a2b29c 576 /// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax 146:a45f49a2b29c 577 void UDPpacket()
nixnax 146:a45f49a2b29c 578 {
nixnax 163:d1b4328e9f08 579 struct {
nixnax 163:d1b4328e9f08 580 unsigned int all; // length of entire ip packet
nixnax 163:d1b4328e9f08 581 unsigned int header; // length of ip header
nixnax 163:d1b4328e9f08 582 } ipLength;
nixnax 163:d1b4328e9f08 583
nixnax 163:d1b4328e9f08 584 struct {
nixnax 165:c47826d07e0d 585 unsigned int all; // length of entire udp packet
nixnax 163:d1b4328e9f08 586 unsigned int data; // length of udp data segment
nixnax 163:d1b4328e9f08 587 } udpLength;
nixnax 163:d1b4328e9f08 588
nixnax 163:d1b4328e9f08 589 ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax 163:d1b4328e9f08 590 ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax 171:46b36d4edd1d 591 udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax 163:d1b4328e9f08 592 udpLength.data = udpLength.all - 8; // size of udp data
nixnax 147:0f40005cbc5f 593
nixnax 146:a45f49a2b29c 594 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 171:46b36d4edd1d 595 char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax 171:46b36d4edd1d 596 char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax 163:d1b4328e9f08 597
nixnax 171:46b36d4edd1d 598 unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax 171:46b36d4edd1d 599 unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax 163:d1b4328e9f08 600
nixnax 163:d1b4328e9f08 601 if(v0) {
nixnax 163:d1b4328e9f08 602 debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax 163:d1b4328e9f08 603 debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax 163:d1b4328e9f08 604 debugPrintf("Len %03d", udpLength);
nixnax 163:d1b4328e9f08 605 }
nixnax 146:a45f49a2b29c 606 if (v1) {
nixnax 163:d1b4328e9f08 607 int printSize = udpLength.data;
nixnax 146:a45f49a2b29c 608 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 146:a45f49a2b29c 609 for (int i=0; i<printSize; i++) {
nixnax 163:d1b4328e9f08 610 char ch = ppp.udp->data[i];
nixnax 146:a45f49a2b29c 611 if (ch>31 && ch<127) {
nixnax 146:a45f49a2b29c 612 debugPrintf("%c", ch);
nixnax 146:a45f49a2b29c 613 } else {
nixnax 146:a45f49a2b29c 614 debugPrintf("_");
nixnax 146:a45f49a2b29c 615 }
nixnax 146:a45f49a2b29c 616 }
nixnax 146:a45f49a2b29c 617 }
nixnax 146:a45f49a2b29c 618 if (v0) debugPrintf("\n");
nixnax 146:a45f49a2b29c 619 #endif
nixnax 163:d1b4328e9f08 620 int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax 163:d1b4328e9f08 621 int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax 146:a45f49a2b29c 622 if ( (echoFound) || (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax 146:a45f49a2b29c 623 if (echoFound) {
nixnax 171:46b36d4edd1d 624 swapIpAddresses(); // swap IP source and destination
nixnax 171:46b36d4edd1d 625 swapIpPorts(); // swap IP source and destination ports
nixnax 163:d1b4328e9f08 626 memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax 170:3d3b2126181c 627 int n=0;
nixnax 170:3d3b2126181c 628 n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax 168:c77eb908042a 629 udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax 171:46b36d4edd1d 630 // we may have changed data length, update all the lengths
nixnax 171:46b36d4edd1d 631 udpLength.all = udpLength.data+8; // update local udp packet length
nixnax 171:46b36d4edd1d 632 ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax 171:46b36d4edd1d 633 ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax 171:46b36d4edd1d 634 ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax 171:46b36d4edd1d 635 ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax 171:46b36d4edd1d 636 IpHeaderCheckSum(); // refresh IP header checksum
nixnax 171:46b36d4edd1d 637 checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax 171:46b36d4edd1d 638 ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 171:46b36d4edd1d 639 unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax 171:46b36d4edd1d 640 ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 171:46b36d4edd1d 641 sendPppFrame(); // send the UDP message back
nixnax 171:46b36d4edd1d 642 } else if ( testFound ) {
nixnax 171:46b36d4edd1d 643 unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax 171:46b36d4edd1d 644 unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax 171:46b36d4edd1d 645 unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax 171:46b36d4edd1d 646 unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax 172:449dd7a28955 647 int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter);
nixnax 171:46b36d4edd1d 648 sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax 146:a45f49a2b29c 649 }
nixnax 146:a45f49a2b29c 650 }
nixnax 142:54d1543e23e5 651 }
nixnax 142:54d1543e23e5 652
nixnax 174:e5a3f16421a5 653 /// UDP demo that sends a udp packet containing a character received from the second debug serial port.
nixnax 174:e5a3f16421a5 654 /// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
nixnax 178:3f17aa0ce5ce 655 /// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
nixnax 178:3f17aa0ce5ce 656 /// See http://www.wikihow.com/Enable-IP-Routing.
nixnax 179:ba2b2ddd0da5 657 /// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
nixnax 179:ba2b2ddd0da5 658 /// The netcat UDP receive command on the remote host would be: nc -ul 12345
nixnax 174:e5a3f16421a5 659 void sendUdpData()
nixnax 174:e5a3f16421a5 660 {
nixnax 174:e5a3f16421a5 661 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 179:ba2b2ddd0da5 662 if (ppp.online) {
nixnax 179:ba2b2ddd0da5 663 if (xx.readable()) {
nixnax 179:ba2b2ddd0da5 664 char inchar = xx.getc();
nixnax 179:ba2b2ddd0da5 665 xx.putc( inchar ); // echo the received character on the debug serial port
nixnax 179:ba2b2ddd0da5 666 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 667 }
nixnax 174:e5a3f16421a5 668 }
nixnax 174:e5a3f16421a5 669 #endif
nixnax 174:e5a3f16421a5 670 }
nixnax 174:e5a3f16421a5 671
nixnax 142:54d1543e23e5 672 /// handle a PING ICMP (internet control message protocol) packet
nixnax 142:54d1543e23e5 673 void ICMPpacket() // internet control message protocol
nixnax 142:54d1543e23e5 674 {
nixnax 165:c47826d07e0d 675 struct {
nixnax 165:c47826d07e0d 676 unsigned int all; // length of entire ip packet
nixnax 165:c47826d07e0d 677 unsigned int header; // length of ip header
nixnax 165:c47826d07e0d 678 } ipLength;
nixnax 165:c47826d07e0d 679 struct {
nixnax 165:c47826d07e0d 680 unsigned int all; // length of entire udp packet
nixnax 165:c47826d07e0d 681 unsigned int data; // length of udp data segment
nixnax 165:c47826d07e0d 682 } icmpLength;
nixnax 165:c47826d07e0d 683 ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax 165:c47826d07e0d 684 ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax 165:c47826d07e0d 685 ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax 165:c47826d07e0d 686 icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax 165:c47826d07e0d 687 icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax 142:54d1543e23e5 688 #define ICMP_TYPE_PING_REQUEST 8
nixnax 165:c47826d07e0d 689 if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax 165:c47826d07e0d 690 ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax 147:0f40005cbc5f 691 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 167:ff8a2d8beeb1 692 char * srcAdr = ppp.ip->srcAdrPtr;
nixnax 167:ff8a2d8beeb1 693 char * dstAdr = ppp.ip->dstAdrPtr;
nixnax 165:c47826d07e0d 694 int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax 165:c47826d07e0d 695 int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax 142:54d1543e23e5 696 if(1) {
nixnax 142:54d1543e23e5 697 char pbuf[50];
nixnax 142:54d1543e23e5 698 checkPc();
nixnax 142:54d1543e23e5 699 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 700 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 701 checkPc();
nixnax 142:54d1543e23e5 702 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 142:54d1543e23e5 703 checkPc();
nixnax 142:54d1543e23e5 704 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 705 }
nixnax 142:54d1543e23e5 706 #endif
nixnax 147:0f40005cbc5f 707 swapIpAddresses(); // swap the IP source and destination addresses
nixnax 147:0f40005cbc5f 708 IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax 142:54d1543e23e5 709 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 165:c47826d07e0d 710 ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 165:c47826d07e0d 711 ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax 165:c47826d07e0d 712 unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax 165:c47826d07e0d 713 ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax 142:54d1543e23e5 714
nixnax 165:c47826d07e0d 715 int printSize = icmpLength.data; // exclude size of icmp header
nixnax 142:54d1543e23e5 716 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 142:54d1543e23e5 717 if (0) {
nixnax 142:54d1543e23e5 718 for (int i=0; i<printSize; i++) {
nixnax 165:c47826d07e0d 719 char ch = ppp.icmp->data[i];
nixnax 142:54d1543e23e5 720 if (ch>31 && ch<127) {
nixnax 142:54d1543e23e5 721 putcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 722 } else {
nixnax 142:54d1543e23e5 723 putcWhileCheckingInput('_');
nixnax 142:54d1543e23e5 724 }
nixnax 142:54d1543e23e5 725 }
nixnax 142:54d1543e23e5 726 putcWhileCheckingInput('\n');
nixnax 142:54d1543e23e5 727 }
nixnax 144:01d98cf7738e 728 sendPppFrame(); // reply to the ping
nixnax 142:54d1543e23e5 729 } else {
nixnax 142:54d1543e23e5 730 if (v0) {
nixnax 165:c47826d07e0d 731 debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax 142:54d1543e23e5 732 }
nixnax 142:54d1543e23e5 733 }
nixnax 142:54d1543e23e5 734 }
nixnax 142:54d1543e23e5 735
nixnax 142:54d1543e23e5 736 /// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax 142:54d1543e23e5 737 void IGMPpacket()
nixnax 142:54d1543e23e5 738 {
nixnax 142:54d1543e23e5 739 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 142:54d1543e23e5 740 }
nixnax 142:54d1543e23e5 741
nixnax 142:54d1543e23e5 742 /// dump the header of an IP pakcet on the (optional) debug serial port
nixnax 142:54d1543e23e5 743 void dumpHeaderIP (int outGoing)
nixnax 142:54d1543e23e5 744 {
nixnax 142:54d1543e23e5 745 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 142:54d1543e23e5 746 checkPc(); // we are expecting the first character of the next packet
nixnax 155:9c6a1d249e26 747 int IPv4Id = __REV16(ppp.ip->identR);
nixnax 152:025c73b6c0a9 748 char pbuf[80]; // local print buffer
nixnax 142:54d1543e23e5 749 int n=0;
nixnax 142:54d1543e23e5 750 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 142:54d1543e23e5 751 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 752 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 142:54d1543e23e5 753 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 167:ff8a2d8beeb1 754 char * srcAdr = ppp.ip->srcAdrPtr;
nixnax 167:ff8a2d8beeb1 755 char * dstAdr = ppp.ip->dstAdrPtr;
nixnax 142:54d1543e23e5 756 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 757 #endif
nixnax 142:54d1543e23e5 758 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 759 #ifndef TCP_HEADER_DUMP_YES
nixnax 160:bd701ad564cb 760 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 761 #endif
nixnax 142:54d1543e23e5 762 #endif
nixnax 142:54d1543e23e5 763 }
nixnax 142:54d1543e23e5 764
nixnax 142:54d1543e23e5 765 /// dump a TCP header on the optional debug serial port
nixnax 142:54d1543e23e5 766 void dumpHeaderTCP(int outGoing)
nixnax 142:54d1543e23e5 767 {
nixnax 142:54d1543e23e5 768 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 155:9c6a1d249e26 769 char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax 142:54d1543e23e5 770 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 142:54d1543e23e5 771 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 155:9c6a1d249e26 772 memset(flagString,'.', 8); // fill string with "........"
nixnax 156:163c23249731 773 if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax 156:163c23249731 774 if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax 156:163c23249731 775 if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax 156:163c23249731 776 if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax 156:163c23249731 777 if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax 156:163c23249731 778 if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax 156:163c23249731 779 if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax 156:163c23249731 780 if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax 155:9c6a1d249e26 781 flagString[8]=0; // null terminate string
nixnax 142:54d1543e23e5 782 #else
nixnax 156:163c23249731 783 if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax 156:163c23249731 784 if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax 156:163c23249731 785 if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax 156:163c23249731 786 if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax 156:163c23249731 787 if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax 155:9c6a1d249e26 788 flagString[1]=0; // null terminate string
nixnax 142:54d1543e23e5 789 #endif
nixnax 155:9c6a1d249e26 790 putsWhileCheckingInput( flagString );
nixnax 142:54d1543e23e5 791 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 792 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 793 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 160:bd701ad564cb 794 #else
nixnax 160:bd701ad564cb 795 putsWhileCheckingInput("\x1b[30m"); // write a black color after every packet
nixnax 142:54d1543e23e5 796 #endif
nixnax 156:163c23249731 797 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 798 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax 142:54d1543e23e5 799 }
nixnax 142:54d1543e23e5 800 #endif
nixnax 142:54d1543e23e5 801 }
nixnax 142:54d1543e23e5 802
nixnax 143:c5019f856a56 803 /// Encode a buffer in base-64
nixnax 184:4133f557d4d4 804 const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax 142:54d1543e23e5 805 void enc64(char * in, char * out, int len)
nixnax 142:54d1543e23e5 806 {
nixnax 142:54d1543e23e5 807 int i,j,a,b,c;
nixnax 142:54d1543e23e5 808 i=0;
nixnax 142:54d1543e23e5 809 j=0;
nixnax 142:54d1543e23e5 810 while(1) {
nixnax 142:54d1543e23e5 811 if (i<len) {
nixnax 142:54d1543e23e5 812 a = in[i++];
nixnax 142:54d1543e23e5 813 out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax 142:54d1543e23e5 814 } else break;
nixnax 142:54d1543e23e5 815 if (i<len) {
nixnax 142:54d1543e23e5 816 b = in[i++];
nixnax 142:54d1543e23e5 817 out[j++] = lut[ ( (a << 4) & 0x30) | ( (b >> 4) & 0x0f) ];
nixnax 142:54d1543e23e5 818 out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax 142:54d1543e23e5 819 } else out[j++] = '=';
nixnax 142:54d1543e23e5 820 if (i<len) {
nixnax 142:54d1543e23e5 821 c = in[i++];
nixnax 142:54d1543e23e5 822 j--;
nixnax 142:54d1543e23e5 823 out[j++] = lut[ ( (b << 2) & 0x3c) | ( (c >> 6) & 0x03) ];
nixnax 142:54d1543e23e5 824 out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax 142:54d1543e23e5 825 } else out[j++] = '=';
nixnax 142:54d1543e23e5 826 }
nixnax 142:54d1543e23e5 827 out[j]=0;
nixnax 142:54d1543e23e5 828 }
nixnax 142:54d1543e23e5 829
nixnax 160:bd701ad564cb 830 /// Handle a request for an http websocket.
nixnax 160:bd701ad564cb 831 /// 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 832 int webSocketHandler(char * dataStart)
nixnax 142:54d1543e23e5 833 {
nixnax 142:54d1543e23e5 834 int n=0; // byte counter
nixnax 184:4133f557d4d4 835 char * key = strstr(dataStart, "Sec-WebSocket-Key:"); // search for the key in the payload
nixnax 142:54d1543e23e5 836 if (key != NULL) {
nixnax 184:4133f557d4d4 837 key = key + 18; // skip over the key ident string "Sec-WebSocket-Key:"
nixnax 142:54d1543e23e5 838 if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax 184:4133f557d4d4 839 while ( strchr(lut, *key) == NULL) key++; // skip non-valid base-64 characters (whitespace)
nixnax 184:4133f557d4d4 840 char challenge [80];
nixnax 184:4133f557d4d4 841 int i=0;
nixnax 184:4133f557d4d4 842 char * copyTo = challenge;
nixnax 184:4133f557d4d4 843 while (strchr(lut, *key) != NULL) { // copy while we see valid base-64 characters
nixnax 184:4133f557d4d4 844 if (i++ >40) break; // prevent buffer overflow
nixnax 184:4133f557d4d4 845 *copyTo++ = *key++; // copy next valid base-64 character
nixnax 184:4133f557d4d4 846 }
nixnax 184:4133f557d4d4 847 strcpy(copyTo,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // append websocket gui code
nixnax 184:4133f557d4d4 848 if (0) debugPrintf("Challenge is %s\n", challenge); // the string we hash for the challenge
nixnax 142:54d1543e23e5 849 char shaOutput [20]; // sha1 output
nixnax 184:4133f557d4d4 850 sha1( shaOutput, challenge, strlen(challenge)); // hash the challenge
nixnax 142:54d1543e23e5 851 char encOut[50];
nixnax 184:4133f557d4d4 852 enc64( shaOutput, encOut, 20); // base-64 encode
nixnax 142:54d1543e23e5 853 char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax 142:54d1543e23e5 854 char * version = challenge;
nixnax 184:4133f557d4d4 855 strncpy(version, versionstring,70); // copy their version string
nixnax 142:54d1543e23e5 856 *strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax 142:54d1543e23e5 857 memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax 142:54d1543e23e5 858 n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax 142:54d1543e23e5 859 n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax 142:54d1543e23e5 860 n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax 142:54d1543e23e5 861 n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax 142:54d1543e23e5 862 n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax 142:54d1543e23e5 863 n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax 142:54d1543e23e5 864 n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax 142:54d1543e23e5 865 }
nixnax 142:54d1543e23e5 866 return n; // this response should satisfy a web browser's websocket protocol request
nixnax 142:54d1543e23e5 867 }
nixnax 142:54d1543e23e5 868
nixnax 142:54d1543e23e5 869 #define TCP_FLAG_ACK (1<<4)
nixnax 142:54d1543e23e5 870 #define TCP_FLAG_SYN (1<<1)
nixnax 142:54d1543e23e5 871 #define TCP_FLAG_PSH (1<<3)
nixnax 142:54d1543e23e5 872 #define TCP_FLAG_RST (1<<2)
nixnax 142:54d1543e23e5 873 #define TCP_FLAG_FIN (1<<0)
nixnax 142:54d1543e23e5 874
nixnax 142:54d1543e23e5 875 /// respond to an HTTP request
nixnax 185:4cd8f91e9d49 876 int httpResponse(char * dataStart, int * flags)
nixnax 142:54d1543e23e5 877 {
nixnax 142:54d1543e23e5 878 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 879 n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax 160:bd701ad564cb 880 if (n>0) return n; // if n>0 we already have a response, so return
nixnax 142:54d1543e23e5 881
nixnax 142:54d1543e23e5 882 int nHeader; // byte size of HTTP header
nixnax 142:54d1543e23e5 883 int contentLengthStart; // index where HTML starts
nixnax 142:54d1543e23e5 884 int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax 185:4cd8f91e9d49 885 *flags = TCP_FLAG_ACK | TCP_FLAG_FIN; // the default case is that we close the connection
nixnax 142:54d1543e23e5 886
nixnax 142:54d1543e23e5 887 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax 142:54d1543e23e5 888 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 889 httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 890 httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 891 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 142:54d1543e23e5 892 if( (httpGetRoot==0) || (httpGetx==0) ) {
nixnax 142:54d1543e23e5 893 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax 142:54d1543e23e5 894 } else {
nixnax 142:54d1543e23e5 895 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 142:54d1543e23e5 896 }
nixnax 142:54d1543e23e5 897 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 142:54d1543e23e5 898 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 142:54d1543e23e5 899 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 142:54d1543e23e5 900 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 142:54d1543e23e5 901 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 902 nHeader=n; // size of HTTP header
nixnax 185:4cd8f91e9d49 903
nixnax 142:54d1543e23e5 904 if( httpGetRoot == 0 ) {
nixnax 142:54d1543e23e5 905 // this is where we insert our web page into the buffer
nixnax 142:54d1543e23e5 906 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 142:54d1543e23e5 907 n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax 185:4cd8f91e9d49 908
nixnax 142:54d1543e23e5 909 } else if ( (httpGet5 == 'w') && (httpGet6 == 's') ) { // "ws" is a special page for websocket demo
nixnax 142:54d1543e23e5 910 memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax 142:54d1543e23e5 911 n = n + sizeof(webSocketPage)-1; // one less than size
nixnax 185:4cd8f91e9d49 912 *flags = TCP_FLAG_ACK | TCP_FLAG_PSH; // for a websocket page we do NOT close the connection
nixnax 142:54d1543e23e5 913 } else {
nixnax 142:54d1543e23e5 914 if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax 142:54d1543e23e5 915 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 142:54d1543e23e5 916 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 142:54d1543e23e5 917 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 142:54d1543e23e5 918 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax 146:a45f49a2b29c 919 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax 142:54d1543e23e5 920 #else
nixnax 142:54d1543e23e5 921 if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax 167:ff8a2d8beeb1 922 n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax 142:54d1543e23e5 923 }
nixnax 142:54d1543e23e5 924 // /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax 146:a45f49a2b29c 925 n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax 142:54d1543e23e5 926 #endif
nixnax 142:54d1543e23e5 927 } else {
nixnax 142:54d1543e23e5 928 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 142:54d1543e23e5 929 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax 142:54d1543e23e5 930 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 142:54d1543e23e5 931 }
nixnax 142:54d1543e23e5 932 }
nixnax 142:54d1543e23e5 933 #define CONTENTLENGTHSIZE 5
nixnax 142:54d1543e23e5 934 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 142:54d1543e23e5 935 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 142:54d1543e23e5 936 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 142:54d1543e23e5 937 return n; // total byte size of our response
nixnax 142:54d1543e23e5 938 }
nixnax 142:54d1543e23e5 939
nixnax 160:bd701ad564cb 940 /// Handle TCP data that is not an HTTP GET.
nixnax 160:bd701ad564cb 941 /// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax 160:bd701ad564cb 942 /// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax 142:54d1543e23e5 943 int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax 142:54d1543e23e5 944 {
nixnax 142:54d1543e23e5 945 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 946 if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax 160:bd701ad564cb 947 char mask [4];
nixnax 160:bd701ad564cb 948 memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax 160:bd701ad564cb 949 int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax 160:bd701ad564cb 950 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 951 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 952 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 953 memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax 160:bd701ad564cb 954 n = len; // our response size remains exactly the same length as what we received
nixnax 142:54d1543e23e5 955 } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax 142:54d1543e23e5 956 n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax 142:54d1543e23e5 957 dataStart[1]=0; // we don't have mask bytes on
nixnax 160:bd701ad564cb 958 } else {
nixnax 184:4133f557d4d4 959 if ( len > 1 ) { // we assume a length of 1 is a keep-alive or push packet
nixnax 184:4133f557d4d4 960 if (v1) putsWhileCheckingInput("TCP data received\n"); // all other tcp push packets
nixnax 184:4133f557d4d4 961 }
nixnax 163:d1b4328e9f08 962 }
nixnax 142:54d1543e23e5 963 return n; // total byte size of our response
nixnax 142:54d1543e23e5 964 }
nixnax 142:54d1543e23e5 965
nixnax 173:6774a0c851c4 966 /// dump the TCP data to the debug serial port
nixnax 173:6774a0c851c4 967 void dumpDataTCP(int outGoing)
nixnax 173:6774a0c851c4 968 {
nixnax 173:6774a0c851c4 969 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 173:6774a0c851c4 970 if (v2) {
nixnax 173:6774a0c851c4 971 int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax 173:6774a0c851c4 972 int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax 173:6774a0c851c4 973 ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax 173:6774a0c851c4 974 int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax 173:6774a0c851c4 975 ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
nixnax 173:6774a0c851c4 976 int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax 173:6774a0c851c4 977 int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax 173:6774a0c851c4 978 char pbuf[80]; // local print buffer
nixnax 173:6774a0c851c4 979 int n=0;
nixnax 173:6774a0c851c4 980 checkPc();
nixnax 173:6774a0c851c4 981 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 173:6774a0c851c4 982 checkPc();
nixnax 173:6774a0c851c4 983 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 984 if (n>70) putsWhileCheckingInput("n>pbuf overflow in dumpDataTCP()\n");
nixnax 173:6774a0c851c4 985 checkPc();
nixnax 173:6774a0c851c4 986 putsWhileCheckingInput( pbuf );
nixnax 173:6774a0c851c4 987 if (tcpDataSize > 0) {
nixnax 173:6774a0c851c4 988 ppp.tcpData[tcpDataSize]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 173:6774a0c851c4 989 putsWhileCheckingInput( ppp.tcpData ); // print the tcp payload data
nixnax 173:6774a0c851c4 990 putsWhileCheckingInput("\n");
nixnax 173:6774a0c851c4 991 }
nixnax 173:6774a0c851c4 992 putsWhileCheckingInput( "\x1b[30m" ); // VT100 color code, print black
nixnax 173:6774a0c851c4 993 }
nixnax 173:6774a0c851c4 994 #endif
nixnax 173:6774a0c851c4 995 }
nixnax 173:6774a0c851c4 996
nixnax 142:54d1543e23e5 997 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 998 /// 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 999 void tcpHandler()
nixnax 142:54d1543e23e5 1000 {
nixnax 154:18b2bd92f557 1001 int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax 154:18b2bd92f557 1002 int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax 173:6774a0c851c4 1003 ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate TCP header start
nixnax 154:18b2bd92f557 1004 int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax 154:18b2bd92f557 1005 int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax 173:6774a0c851c4 1006 char * tcpDataIn = ppp.tcpStart + headerSizeTcp; // start of data TCP data after TCP header
nixnax 154:18b2bd92f557 1007 int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax 154:18b2bd92f557 1008
nixnax 154:18b2bd92f557 1009 unsigned int seq_in = __REV(ppp.tcp->seqTcpR);
nixnax 154:18b2bd92f557 1010 unsigned int ack_in = __REV(ppp.tcp->ackTcpR);
nixnax 142:54d1543e23e5 1011 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 142:54d1543e23e5 1012 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 142:54d1543e23e5 1013
nixnax 142:54d1543e23e5 1014 // first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax 173:6774a0c851c4 1015 headerSizeIp=20;
nixnax 173:6774a0c851c4 1016 ppp.ip->headerLength = headerSizeIp/4; // ip header is 20 bytes long
nixnax 173:6774a0c851c4 1017 ppp.ip->lengthR = __REV(40); // 20 ip header + 20 tcp header
nixnax 173:6774a0c851c4 1018 //tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 154:18b2bd92f557 1019 headerSizeTcp = 20; // shorten outgoing TCP header size 20 bytes
nixnax 173:6774a0c851c4 1020 ppp.tcpStart = ppp.ipStart + headerSizeIp; // recalc TCP header start
nixnax 154:18b2bd92f557 1021 ppp.tcp->offset = (headerSizeTcp/4);
nixnax 173:6774a0c851c4 1022 char * tcpDataOut = ppp.tcpStart + headerSizeTcp; // start of outgoing data
nixnax 142:54d1543e23e5 1023
nixnax 142:54d1543e23e5 1024 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 142:54d1543e23e5 1025 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 160:bd701ad564cb 1026
nixnax 185:4cd8f91e9d49 1027 ppp.tcp->windowR = __REV16( 1200 ); // set tcp window size to 1200 bytes
nixnax 142:54d1543e23e5 1028
nixnax 142:54d1543e23e5 1029 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 142:54d1543e23e5 1030
nixnax 156:163c23249731 1031 switch ( ppp.tcp->flag.All ) {
nixnax 142:54d1543e23e5 1032 case TCP_FLAG_SYN:
nixnax 142:54d1543e23e5 1033 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 142:54d1543e23e5 1034 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 142:54d1543e23e5 1035 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 1036 break;
nixnax 184:4133f557d4d4 1037 case TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1038 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 184:4133f557d4d4 1039 if ( (ppp.tcp->flag.All == TCP_FLAG_ACK) && (tcpDataSize == 0)) return; // handle zero-size ack messages by ignoring them
nixnax 142:54d1543e23e5 1040 if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax 179:ba2b2ddd0da5 1041 flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // we have data, set the PSH flag
nixnax 185:4cd8f91e9d49 1042 dataLen = httpResponse(tcpDataOut, &flagsOut); // send an http response
nixnax 142:54d1543e23e5 1043 } else {
nixnax 158:841592aed956 1044 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax 179:ba2b2ddd0da5 1045 if (dataLen > 0) flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // if we have any data set the PSH flag
nixnax 142:54d1543e23e5 1046 }
nixnax 142:54d1543e23e5 1047 break;
nixnax 142:54d1543e23e5 1048 case TCP_FLAG_FIN:
nixnax 142:54d1543e23e5 1049 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1050 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1051 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 142:54d1543e23e5 1052 ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 1053 break;
nixnax 142:54d1543e23e5 1054 default:
nixnax 179:ba2b2ddd0da5 1055 return; // ignore all other packets
nixnax 142:54d1543e23e5 1056 } // switch
nixnax 142:54d1543e23e5 1057
nixnax 142:54d1543e23e5 1058 // The TCP flag handling is now done
nixnax 142:54d1543e23e5 1059 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 147:0f40005cbc5f 1060 swapIpAddresses(); // swap IP source and destination addresses
nixnax 149:969d98f6fb88 1061 swapIpPorts(); // swap IP source and destination ports
nixnax 142:54d1543e23e5 1062
nixnax 158:841592aed956 1063 ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax 158:841592aed956 1064 ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax 160:bd701ad564cb 1065
nixnax 156:163c23249731 1066 ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax 142:54d1543e23e5 1067
nixnax 159:4d1bf96a59cd 1068 // recalculate all the header sizes
nixnax 154:18b2bd92f557 1069 tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax 154:18b2bd92f557 1070 int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax 159:4d1bf96a59cd 1071 ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax 142:54d1543e23e5 1072 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 1073
nixnax 142:54d1543e23e5 1074 // the header is all set up, now do the IP and TCP checksums
nixnax 146:a45f49a2b29c 1075 IpHeaderCheckSum(); // calculate new IP header checksum
nixnax 170:3d3b2126181c 1076 checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax 159:4d1bf96a59cd 1077 ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 161:d59f778bc8ab 1078 unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax 159:4d1bf96a59cd 1079 ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 160:bd701ad564cb 1080
nixnax 170:3d3b2126181c 1081 dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax 170:3d3b2126181c 1082 dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax 173:6774a0c851c4 1083 dumpDataTCP(1); // dump outgoing TCP data before sending the frame
nixnax 182:f039ec218c9f 1084 if (0) wait_ms(45); // 45 ms delay before sending frame - a typical internet delay time
nixnax 144:01d98cf7738e 1085 sendPppFrame(); // All preparation complete - send the TCP response
nixnax 142:54d1543e23e5 1086 if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
nixnax 142:54d1543e23e5 1087 memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax 142:54d1543e23e5 1088 }
nixnax 142:54d1543e23e5 1089
nixnax 142:54d1543e23e5 1090 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 1091 void TCPpacket()
nixnax 142:54d1543e23e5 1092 {
nixnax 173:6774a0c851c4 1093 dumpHeaderIP(0); // dump incoming packet IP header
nixnax 173:6774a0c851c4 1094 dumpHeaderTCP(0); // dump incoming packet TCP header
nixnax 173:6774a0c851c4 1095 dumpDataTCP(0); // dump incoming packet data
nixnax 142:54d1543e23e5 1096 tcpHandler();
nixnax 142:54d1543e23e5 1097 }
nixnax 142:54d1543e23e5 1098
nixnax 142:54d1543e23e5 1099 /// handle the remaining IP protocols by ignoring them
nixnax 142:54d1543e23e5 1100 void otherProtocol()
nixnax 142:54d1543e23e5 1101 {
nixnax 142:54d1543e23e5 1102 debugPrintf("Other IP protocol");
nixnax 142:54d1543e23e5 1103 }
nixnax 142:54d1543e23e5 1104
nixnax 142:54d1543e23e5 1105 /// process an incoming IP packet
nixnax 142:54d1543e23e5 1106 void IPframe()
nixnax 142:54d1543e23e5 1107 {
nixnax 167:ff8a2d8beeb1 1108 int protocol = ppp.ip->protocol;
nixnax 142:54d1543e23e5 1109 switch (protocol) {
nixnax 142:54d1543e23e5 1110 case 1:
nixnax 142:54d1543e23e5 1111 ICMPpacket();
nixnax 142:54d1543e23e5 1112 break;
nixnax 142:54d1543e23e5 1113 case 2:
nixnax 142:54d1543e23e5 1114 IGMPpacket();
nixnax 142:54d1543e23e5 1115 break;
nixnax 142:54d1543e23e5 1116 case 17:
nixnax 142:54d1543e23e5 1117 UDPpacket();
nixnax 142:54d1543e23e5 1118 break;
nixnax 142:54d1543e23e5 1119 case 6:
nixnax 142:54d1543e23e5 1120 TCPpacket();
nixnax 142:54d1543e23e5 1121 break;
nixnax 142:54d1543e23e5 1122 default:
nixnax 142:54d1543e23e5 1123 otherProtocol();
nixnax 142:54d1543e23e5 1124 }
nixnax 142:54d1543e23e5 1125 }
nixnax 142:54d1543e23e5 1126
nixnax 142:54d1543e23e5 1127 /// respond to LCP (line configuration protocol) configuration request) by allowing no options
nixnax 142:54d1543e23e5 1128 void LCPconfReq()
nixnax 142:54d1543e23e5 1129 {
nixnax 142:54d1543e23e5 1130 debugPrintf("LCP Config ");
nixnax 175:b4e6f8a6fe00 1131 if ( ppp.lcp->lengthR != __REV16(4) ) {
nixnax 175:b4e6f8a6fe00 1132 ppp.lcp->code=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 142:54d1543e23e5 1133 debugPrintf("Reject\n");
nixnax 144:01d98cf7738e 1134 sendPppFrame();
nixnax 142:54d1543e23e5 1135 } else {
nixnax 175:b4e6f8a6fe00 1136 ppp.lcp->code=2; // ack zero conf
nixnax 142:54d1543e23e5 1137 debugPrintf("Ack\n");
nixnax 144:01d98cf7738e 1138 sendPppFrame();
nixnax 142:54d1543e23e5 1139 debugPrintf("LCP Ask\n");
nixnax 175:b4e6f8a6fe00 1140 ppp.lcp->code=1; // request no options
nixnax 144:01d98cf7738e 1141 sendPppFrame();
nixnax 142:54d1543e23e5 1142 }
nixnax 142:54d1543e23e5 1143 }
nixnax 142:54d1543e23e5 1144
nixnax 142:54d1543e23e5 1145 /// handle LCP acknowledge packets by ignoring them
nixnax 142:54d1543e23e5 1146 void LCPconfAck()
nixnax 142:54d1543e23e5 1147 {
nixnax 142:54d1543e23e5 1148 debugPrintf("LCP Ack\n");
nixnax 142:54d1543e23e5 1149 }
nixnax 142:54d1543e23e5 1150
nixnax 143:c5019f856a56 1151 /// handle LCP end (disconnect) packets by acknowledging them and by setting ppp.online to false
nixnax 142:54d1543e23e5 1152 void LCPend()
nixnax 142:54d1543e23e5 1153 {
nixnax 175:b4e6f8a6fe00 1154 ppp.lcp->code=6; // end
nixnax 144:01d98cf7738e 1155 sendPppFrame(); // acknowledge
nixnax 142:54d1543e23e5 1156 ppp.online=0; // start hunting for connect string again
nixnax 142:54d1543e23e5 1157 pppInitStruct(); // flush the receive buffer
nixnax 143:c5019f856a56 1158 debugPrintf("LCP End (Disconnect from host)\n");
nixnax 142:54d1543e23e5 1159 }
nixnax 142:54d1543e23e5 1160
nixnax 142:54d1543e23e5 1161 /// respond to other LCP requests by ignoring them
nixnax 142:54d1543e23e5 1162 void LCPother()
nixnax 142:54d1543e23e5 1163 {
nixnax 142:54d1543e23e5 1164 debugPrintf("LCP Other\n");
nixnax 142:54d1543e23e5 1165 dumpPPPFrame();
nixnax 142:54d1543e23e5 1166 }
nixnax 142:54d1543e23e5 1167
nixnax 142:54d1543e23e5 1168 /// process incoming LCP packets
nixnax 142:54d1543e23e5 1169 void LCPframe()
nixnax 142:54d1543e23e5 1170 {
nixnax 175:b4e6f8a6fe00 1171 int code = ppp.lcp->code;
nixnax 142:54d1543e23e5 1172 switch (code) {
nixnax 142:54d1543e23e5 1173 case 1:
nixnax 142:54d1543e23e5 1174 LCPconfReq();
nixnax 142:54d1543e23e5 1175 break; // config request
nixnax 142:54d1543e23e5 1176 case 2:
nixnax 142:54d1543e23e5 1177 LCPconfAck();
nixnax 142:54d1543e23e5 1178 break; // config ack
nixnax 142:54d1543e23e5 1179 case 5:
nixnax 142:54d1543e23e5 1180 LCPend();
nixnax 142:54d1543e23e5 1181 break; // end connection
nixnax 142:54d1543e23e5 1182 default:
nixnax 142:54d1543e23e5 1183 LCPother();
nixnax 142:54d1543e23e5 1184 }
nixnax 142:54d1543e23e5 1185 }
nixnax 142:54d1543e23e5 1186
nixnax 142:54d1543e23e5 1187 /// discard packets that are not IP, IPCP, or LCP
nixnax 142:54d1543e23e5 1188 void discardedFrame()
nixnax 142:54d1543e23e5 1189 {
nixnax 142:54d1543e23e5 1190 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 1191 }
nixnax 142:54d1543e23e5 1192
nixnax 142:54d1543e23e5 1193 /// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax 142:54d1543e23e5 1194 void determinePacketType()
nixnax 142:54d1543e23e5 1195 {
nixnax 167:ff8a2d8beeb1 1196 if ( ppp.ppp->address != 0xff ) {
nixnax 167:ff8a2d8beeb1 1197 debugPrintf("Unexpected: PPP address != ff\n");
nixnax 142:54d1543e23e5 1198 return;
nixnax 142:54d1543e23e5 1199 }
nixnax 167:ff8a2d8beeb1 1200 if ( ppp.ppp->control != 3 ) {
nixnax 167:ff8a2d8beeb1 1201 debugPrintf("Unexpected: PPP control != 3\n");
nixnax 142:54d1543e23e5 1202 return;
nixnax 142:54d1543e23e5 1203 }
nixnax 167:ff8a2d8beeb1 1204 unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax 167:ff8a2d8beeb1 1205 switch ( protocol ) {
nixnax 167:ff8a2d8beeb1 1206 case 0xc021:
nixnax 142:54d1543e23e5 1207 LCPframe();
nixnax 142:54d1543e23e5 1208 break; // link control
nixnax 167:ff8a2d8beeb1 1209 case 0x8021:
nixnax 142:54d1543e23e5 1210 IPCPframe();
nixnax 142:54d1543e23e5 1211 break; // IP control
nixnax 167:ff8a2d8beeb1 1212 case 0x0021:
nixnax 142:54d1543e23e5 1213 IPframe();
nixnax 142:54d1543e23e5 1214 break; // IP itself
nixnax 142:54d1543e23e5 1215 default:
nixnax 142:54d1543e23e5 1216 discardedFrame();
nixnax 142:54d1543e23e5 1217 }
nixnax 142:54d1543e23e5 1218 }
nixnax 142:54d1543e23e5 1219
nixnax 146:a45f49a2b29c 1220 /// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 146:a45f49a2b29c 1221 void sniff()
nixnax 146:a45f49a2b29c 1222 {
nixnax 146:a45f49a2b29c 1223 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 1224 }
nixnax 146:a45f49a2b29c 1225
nixnax 142:54d1543e23e5 1226 /// scan the PPP serial input stream for frame start markers
nixnax 143:c5019f856a56 1227 void waitForPppFrame()
nixnax 142:54d1543e23e5 1228 {
nixnax 142:54d1543e23e5 1229 while(1) {
nixnax 182:f039ec218c9f 1230 sendUdpData(); // handle received characters from the DEBUG TERMINAL
nixnax 142:54d1543e23e5 1231 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 142:54d1543e23e5 1232 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 142:54d1543e23e5 1233 int rx = pc_getBuf(); // get the character
nixnax 142:54d1543e23e5 1234 if (rx==FRAME_7E) {
nixnax 142:54d1543e23e5 1235 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 142:54d1543e23e5 1236 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1237 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 181:bcfe7fe2142d 1238 ppp.firstFrame=0; // clear first frame flag
nixnax 142:54d1543e23e5 1239 } else {
nixnax 142:54d1543e23e5 1240 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 142:54d1543e23e5 1241 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 142:54d1543e23e5 1242 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1243 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax 142:54d1543e23e5 1244 break;
nixnax 142:54d1543e23e5 1245 }
nixnax 142:54d1543e23e5 1246 }
nixnax 142:54d1543e23e5 1247 }
nixnax 142:54d1543e23e5 1248 }
nixnax 142:54d1543e23e5 1249 }
nixnax 142:54d1543e23e5 1250
nixnax 153:7993def8663f 1251 /// 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 1252 // Note: a 0x7E in the input stream (ppp start of frame character) will also set ppp.online to true - see checkPc();
nixnax 153:7993def8663f 1253 void waitForPcConnectString()
nixnax 142:54d1543e23e5 1254 {
nixnax 142:54d1543e23e5 1255 while(ppp.online == 0) {
nixnax 142:54d1543e23e5 1256 checkPc(); // gather received characters
nixnax 142:54d1543e23e5 1257 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 142:54d1543e23e5 1258 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 142:54d1543e23e5 1259 if (found1 != NULL) {
nixnax 142:54d1543e23e5 1260 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 143:c5019f856a56 1261 if (v0) debugPrintf("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 142:54d1543e23e5 1262 pc.puts("CLIENTSERVER");
nixnax 142:54d1543e23e5 1263 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 142:54d1543e23e5 1264 checkPc();
nixnax 142:54d1543e23e5 1265 }
nixnax 142:54d1543e23e5 1266 }
nixnax 142:54d1543e23e5 1267 }
nixnax 142:54d1543e23e5 1268
nixnax 144:01d98cf7738e 1269 /// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax 144:01d98cf7738e 1270 void initializePpp()
nixnax 142:54d1543e23e5 1271 {
nixnax 144:01d98cf7738e 1272 debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax 184:4133f557d4d4 1273 debugPrintf("\x1b[2J\x1b[H\x1b[30m");
nixnax 184:4133f557d4d4 1274 wait_ms(200); // a brief wait so a human can see the reset event
nixnax 184:4133f557d4d4 1275 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 1276
nixnax 179:ba2b2ddd0da5 1277 pppInitStruct(); // initialize all the variables/properties/buffers
nixnax 179:ba2b2ddd0da5 1278 pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
nixnax 179:ba2b2ddd0da5 1279 pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
nixnax 143:c5019f856a56 1280 }