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@171:46b36d4edd1d, 2017-09-04 (annotated)

Committer:
nixnax
Date:
Mon Sep 04 08:49:25 2017 +0000
Revision:
171:46b36d4edd1d
Parent:
170:3d3b2126181c
Child:
172:449dd7a28955
sendUdp();

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 142:54d1543e23e5 1 // PPP-Blinky - "The Most Basic Internet Of a Thing"
nixnax 142:54d1543e23e5 2 // A Tiny HTTP Webserver Using Windows XP/7/8/10/Linux Dial-Up Networking Over A Serial Port.
nixnax 142:54d1543e23e5 3 // Receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 142:54d1543e23e5 4 // WebSocket Service - see https://en.wikipedia.org/wiki/WebSocket
nixnax 142:54d1543e23e5 5
nixnax 142:54d1543e23e5 6 // Copyright 2016/2017 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax 142:54d1543e23e5 7
nixnax 142:54d1543e23e5 8 // Notes and Instructions
nixnax 142:54d1543e23e5 9 // http://bit.ly/PPP-Blinky-Instructions
nixnax 142:54d1543e23e5 10 // http://bit.ly/win-rasdial-config
nixnax 142:54d1543e23e5 11
nixnax 142:54d1543e23e5 12 // Handy reading material
nixnax 142:54d1543e23e5 13 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 142:54d1543e23e5 14 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 142:54d1543e23e5 15 // http://atari.kensclassics.org/wcomlog.htm
nixnax 142:54d1543e23e5 16
nixnax 142:54d1543e23e5 17 // Handy tools
nixnax 142:54d1543e23e5 18 // https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax 142:54d1543e23e5 19 // https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax 142:54d1543e23e5 20 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 142:54d1543e23e5 21 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE), then custom relected-in=1, reflected-out=1
nixnax 142:54d1543e23e5 22 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 142:54d1543e23e5 23 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 142:54d1543e23e5 24 // Windows Powershell invoke-webrequest command - use it to stress test the webserver like this: while (1){ invoke-webrequest -uri 172.10.10.1/x }
nixnax 142:54d1543e23e5 25
nixnax 142:54d1543e23e5 26 // Connecting PPP-Blinky to Linux
nixnax 142:54d1543e23e5 27 // PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax 142:54d1543e23e5 28 // pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax 142:54d1543e23e5 29 // in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax 142:54d1543e23e5 30 // See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax 142:54d1543e23e5 31
nixnax 142:54d1543e23e5 32 // Special pages when PPP-Blinky is running
nixnax 142:54d1543e23e5 33 // 172.10.10.2 root page
nixnax 143:c5019f856a56 34 // 172.10.10.2/x returns a number that increments every time you request a page - this is handy for testing
nixnax 146:a45f49a2b29c 35 // 172.10.10.2/xb also returns a number, 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 142:54d1543e23e5 37 // http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle
nixnax 142:54d1543e23e5 38
nixnax 142:54d1543e23e5 39 // Ok, enough talking, time to check out some code!!
nixnax 142:54d1543e23e5 40
nixnax 142:54d1543e23e5 41 #include "ppp-blinky.h"
nixnax 142:54d1543e23e5 42
nixnax 142:54d1543e23e5 43 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax 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 169:ee90aed3a735 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 142:54d1543e23e5 53 Serial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax 142:54d1543e23e5 54 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
nixnax 142:54d1543e23e5 55 Serial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax 142:54d1543e23e5 56 #elif defined(TARGET_LPC11U24)
nixnax 142:54d1543e23e5 57 #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 58 #elif defined (TARGET_KL46Z) || (TARGET_KL25Z)
nixnax 142:54d1543e23e5 59 Serial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax 142:54d1543e23e5 60 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 142:54d1543e23e5 61 // change the next line to YOUR target board's second serial port pin definition if it's not present - and if it works, please send it to me - thanks!!!
nixnax 142:54d1543e23e5 62 Serial xx(p9, p10); // change this to YOUR board second serial port pin definition - and please send it to me if it works!!!
nixnax 142:54d1543e23e5 63 #else
nixnax 142:54d1543e23e5 64 #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 65 #endif
nixnax 142:54d1543e23e5 66 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we print debug messages */
nixnax 142:54d1543e23e5 67 #define debugPutc(x...) xx.putc(x)
nixnax 142:54d1543e23e5 68 #define debugBaudRate(x...) xx.baud(x)
nixnax 142:54d1543e23e5 69 #else
nixnax 142:54d1543e23e5 70 // if we don't have a debug port the debug print functions do nothing
nixnax 142:54d1543e23e5 71 #define debugPrintf(x...) {}
nixnax 142:54d1543e23e5 72 #define debugPutc(x...) {}
nixnax 142:54d1543e23e5 73 #define debugBaudRate(x...) {}
nixnax 142:54d1543e23e5 74 #endif
nixnax 142:54d1543e23e5 75
nixnax 142:54d1543e23e5 76 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 142:54d1543e23e5 77 #define v0 1
nixnax 142:54d1543e23e5 78 #define v1 0
nixnax 142:54d1543e23e5 79 #define v2 0
nixnax 142:54d1543e23e5 80 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 142:54d1543e23e5 81 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 142:54d1543e23e5 82
nixnax 142:54d1543e23e5 83 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 142:54d1543e23e5 84 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 142:54d1543e23e5 85
nixnax 142:54d1543e23e5 86 const static char rootWebPage[] = "\
nixnax 142:54d1543e23e5 87 <!DOCTYPE html>\
nixnax 142:54d1543e23e5 88 <html>\
nixnax 142:54d1543e23e5 89 <head>\
nixnax 146:a45f49a2b29c 90 <title>mbed PPP-Blinky</title>\r\n\
nixnax 146:a45f49a2b29c 91 <script>\r\n\
nixnax 142:54d1543e23e5 92 window.onload=function(){\
nixnax 142:54d1543e23e5 93 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 146:a45f49a2b29c 94 x().textContent=parseInt(x().textContent)+1;},100);};\r\n\
nixnax 146:a45f49a2b29c 95 </script>\r\n\
nixnax 142:54d1543e23e5 96 </head>\
nixnax 142:54d1543e23e5 97 <body style=\"font-family: sans-serif; font-size:20px; text-align:center; color:#807070\">\
nixnax 142:54d1543e23e5 98 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 142:54d1543e23e5 99 <h1 id=\"w\">0</h1>\
nixnax 142:54d1543e23e5 100 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 142:54d1543e23e5 101 <h1><a href=\"/ws\">WebSocket Demo</a></h1>\
nixnax 142:54d1543e23e5 102 <h1><a href=\"/x\">Benchmark 1</a></h1>\
nixnax 142:54d1543e23e5 103 <h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax 142:54d1543e23e5 104 <h1><a href=\"http://jsfiddle.net/d26cyuh2/\">JSFiddle Demo</a></h1>\
nixnax 142:54d1543e23e5 105 </body>\
nixnax 146:a45f49a2b29c 106 </html>\r\n"; // size = 644 bytes plus 1 null byte = 645 bytes
nixnax 142:54d1543e23e5 107
nixnax 167:ff8a2d8beeb1 108 // this is a websocket demo html page we serve when GET /ws is requested
nixnax 142:54d1543e23e5 109 const static char webSocketPage[] = "\
nixnax 142:54d1543e23e5 110 <!DOCTYPE html>\
nixnax 142:54d1543e23e5 111 <html>\
nixnax 142:54d1543e23e5 112 <head>\
nixnax 142:54d1543e23e5 113 <title>mbed PPP-Blinky</title>\
nixnax 142:54d1543e23e5 114 <script>\
nixnax 142:54d1543e23e5 115 window.onload=function(){\
nixnax 142:54d1543e23e5 116 var url=\"ws://172.10.10.2\";\
nixnax 142:54d1543e23e5 117 var sts=document.getElementById(\"sts\");\
nixnax 142:54d1543e23e5 118 var btn=document.getElementById(\"btn\");\
nixnax 142:54d1543e23e5 119 var ctr=0;\
nixnax 142:54d1543e23e5 120 function show(text){sts.textContent=text;}\
nixnax 142:54d1543e23e5 121 btn.onclick=function(){\
nixnax 142:54d1543e23e5 122 if(btn.textContent==\"Connect\"){\
nixnax 142:54d1543e23e5 123 x=new WebSocket(url);\
nixnax 142:54d1543e23e5 124 x.onopen=function(){\
nixnax 142:54d1543e23e5 125 show(\"Connected to : \"+url);\
nixnax 142:54d1543e23e5 126 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 142:54d1543e23e5 127 };\
nixnax 142:54d1543e23e5 128 x.onclose=function(){show(\"closed\");};\
nixnax 142:54d1543e23e5 129 x.onmessage=function(msg){show(\"PPP-Blinky Sent: \\\"\"+msg.data+\"\\\"\");};\
nixnax 142:54d1543e23e5 130 } else {\
nixnax 142:54d1543e23e5 131 x.send(ctr);\
nixnax 142:54d1543e23e5 132 ctr=ctr+1;\
nixnax 142:54d1543e23e5 133 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 142:54d1543e23e5 134 }\
nixnax 142:54d1543e23e5 135 };\
nixnax 142:54d1543e23e5 136 };\
nixnax 142:54d1543e23e5 137 </script>\
nixnax 142:54d1543e23e5 138 <body style=\"font-family: sans-serif; font-size:25px; color:#807070\">\
nixnax 142:54d1543e23e5 139 <h1>PPP-Blinky WebSocket Test</h1>\
nixnax 142:54d1543e23e5 140 <div id=\"sts\">Idle</div>\
nixnax 142:54d1543e23e5 141 <button id=\"btn\" style=\"font-size: 100%; margin-top: 55px; margin-bottom: 55px;\">Connect</button>\
nixnax 142:54d1543e23e5 142 <h4><a href=\"/\">PPP-Blinky home</a></h4>\
nixnax 142:54d1543e23e5 143 </body>\
nixnax 142:54d1543e23e5 144 </html>"; // size = 916 bytes + 1 null byte = 917 bytes
nixnax 142:54d1543e23e5 145
nixnax 142:54d1543e23e5 146 // 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 147 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 142:54d1543e23e5 148 // The modem baud rate should be set to 115200 baud
nixnax 142:54d1543e23e5 149 // See instructions at the top.
nixnax 142:54d1543e23e5 150 // On a typical mbed hardware platform this serial port is a USB virtual com port (VCP) and the USB serial driver is supplied by the board vendor.
nixnax 142:54d1543e23e5 151 BufferedSerial pc(USBTX, USBRX, 100); // usb virtual com port for mbed hardware
nixnax 142:54d1543e23e5 152
nixnax 142:54d1543e23e5 153 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 142:54d1543e23e5 154
nixnax 142:54d1543e23e5 155 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 142:54d1543e23e5 156 #define FRAME_7E (0x7e)
nixnax 142:54d1543e23e5 157
nixnax 165:c47826d07e0d 158 /// a structure to keep all our ppp variables in
nixnax 142:54d1543e23e5 159 struct pppType {
nixnax 167:ff8a2d8beeb1 160 union {
nixnax 167:ff8a2d8beeb1 161 pppHeaderType * ppp; // pointer to ppp structure
nixnax 167:ff8a2d8beeb1 162 ipcpHeaderType * ipcp; // pointer to ipcp structure
nixnax 167:ff8a2d8beeb1 163 };
nixnax 154:18b2bd92f557 164 union {
nixnax 154:18b2bd92f557 165 ipHeaderType * ip; // pointer to ip header struct
nixnax 155:9c6a1d249e26 166 char * ipStart; // char pointer to ip header struct (need a char pointer for byte offset calculations)
nixnax 154:18b2bd92f557 167 };
nixnax 167:ff8a2d8beeb1 168 union { // a union for the packet type contained in the IP packet
nixnax 167:ff8a2d8beeb1 169 tcpHeaderType * tcp; // pointer to tcp header struct
nixnax 167:ff8a2d8beeb1 170 udpHeaderType * udp; // pointer to udp header struct
nixnax 165:c47826d07e0d 171 icmpHeaderType * icmp; // pointer to udp header struct
nixnax 167:ff8a2d8beeb1 172 char * tcpStart; // char pointer to tcp header struct (need a char pointer for byte offset calculations)
nixnax 167:ff8a2d8beeb1 173 char * udpStart; // char pointer to udp header struct (need a char pointer for byte offset calculations)
nixnax 165:c47826d07e0d 174 char * icmpStart; // char pointer to icmp header struct (need a char pointer for byte offset calculations)
nixnax 160:bd701ad564cb 175 };
nixnax 142:54d1543e23e5 176 int online; // we hunt for a PPP connection if this is zero
nixnax 143:c5019f856a56 177 int hostIP; // ip address of host
nixnax 145:098b6ed2f7f2 178 int fcs; // PPP "frame check sequence" - a 16-bit HDLC-like checksum used in all PPP frames
nixnax 142:54d1543e23e5 179 int ledState; // state of LED1
nixnax 146:a45f49a2b29c 180 int responseCounter;
nixnax 142:54d1543e23e5 181 int firstFrame; // cleared after first frame
nixnax 159:4d1bf96a59cd 182 unsigned int sum; // a checksum used in headers
nixnax 142:54d1543e23e5 183 struct {
nixnax 142:54d1543e23e5 184 #define RXBUFLEN (1<<11)
nixnax 142:54d1543e23e5 185 // the serial port receive buffer and packet buffer, size is RXBUFLEN (currently 2048 bytes)
nixnax 142:54d1543e23e5 186 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in ring buffer
nixnax 142:54d1543e23e5 187 int head;
nixnax 142:54d1543e23e5 188 int tail;
nixnax 142:54d1543e23e5 189 int rtail;
nixnax 142:54d1543e23e5 190 int buflevel;
nixnax 142:54d1543e23e5 191 } rx; // serial port objects
nixnax 142:54d1543e23e5 192 struct {
nixnax 142:54d1543e23e5 193 int len; // number of bytes in buffer
nixnax 142:54d1543e23e5 194 int crc; // PPP CRC (frame check)
nixnax 152:025c73b6c0a9 195 #define PPP_max_size 1600
nixnax 152:025c73b6c0a9 196 // we are assuming 100 bytes more than MTU size of 1500
nixnax 154:18b2bd92f557 197 char buf[PPP_max_size]; // send and receive buffer large enough for largest IP packet
nixnax 142:54d1543e23e5 198 } pkt; // ppp buffer objects
nixnax 142:54d1543e23e5 199 struct {
nixnax 142:54d1543e23e5 200 int frameStartIndex; // frame start marker
nixnax 142:54d1543e23e5 201 int frameEndIndex; // frame end marker
nixnax 142:54d1543e23e5 202 } hdlc; // hdlc frame objects
nixnax 142:54d1543e23e5 203 struct {
nixnax 142:54d1543e23e5 204 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 154:18b2bd92f557 205 } ipData; // ip related object
nixnax 142:54d1543e23e5 206 };
nixnax 142:54d1543e23e5 207
nixnax 142:54d1543e23e5 208 pppType ppp; // our global - definitely not thread safe
nixnax 142:54d1543e23e5 209
nixnax 142:54d1543e23e5 210 /// Initialize the ppp structure and clear the receive buffer
nixnax 142:54d1543e23e5 211 void pppInitStruct()
nixnax 142:54d1543e23e5 212 {
nixnax 142:54d1543e23e5 213 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 142:54d1543e23e5 214 ppp.online=0;
nixnax 142:54d1543e23e5 215 ppp.rx.tail=0;
nixnax 142:54d1543e23e5 216 ppp.rx.rtail=0;
nixnax 142:54d1543e23e5 217 ppp.rx.head=0;
nixnax 142:54d1543e23e5 218 ppp.rx.buflevel=0;
nixnax 142:54d1543e23e5 219 ppp.pkt.len=0;
nixnax 154:18b2bd92f557 220 ppp.ipData.ident=10000; // easy to recognize in ip packet dumps
nixnax 142:54d1543e23e5 221 ppp.ledState=0;
nixnax 142:54d1543e23e5 222 ppp.hdlc.frameStartIndex=0;
nixnax 146:a45f49a2b29c 223 ppp.responseCounter=0;
nixnax 142:54d1543e23e5 224 ppp.firstFrame=1;
nixnax 154:18b2bd92f557 225 ppp.ppp = (pppHeaderType *)ppp.pkt.buf;
nixnax 154:18b2bd92f557 226 ppp.ip = (ipHeaderType *)(ppp.pkt.buf+4); // ppp header is 4 bytes long
nixnax 142:54d1543e23e5 227 }
nixnax 142:54d1543e23e5 228
nixnax 142:54d1543e23e5 229 /// Toggle the LED on every second PPP packet received
nixnax 142:54d1543e23e5 230 void led1Toggle()
nixnax 142:54d1543e23e5 231 {
nixnax 142:54d1543e23e5 232 led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax 143:c5019f856a56 233 ppp.ledState++;
nixnax 142:54d1543e23e5 234 }
nixnax 142:54d1543e23e5 235
nixnax 152:025c73b6c0a9 236 /// returns 1 after a connect message, 0 at startup or after a disconnect message
nixnax 150:3366bf3d294e 237 int connectedPpp()
nixnax 142:54d1543e23e5 238 {
nixnax 142:54d1543e23e5 239 return ppp.online;
nixnax 143:c5019f856a56 240 }
nixnax 142:54d1543e23e5 241
nixnax 143:c5019f856a56 242 /// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax 143:c5019f856a56 243 /// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax 142:54d1543e23e5 244 void checkPc()
nixnax 142:54d1543e23e5 245 {
nixnax 142:54d1543e23e5 246 char ch;
nixnax 142:54d1543e23e5 247 if ( pc.readable() ) {
nixnax 142:54d1543e23e5 248 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 142:54d1543e23e5 249 if ( hd == ppp.rx.rtail ) {
nixnax 142:54d1543e23e5 250 debugPrintf("\nReceive buffer full\n");
nixnax 142:54d1543e23e5 251 return;
nixnax 142:54d1543e23e5 252 }
nixnax 142:54d1543e23e5 253 ch = pc.getc(); // read new character
nixnax 142:54d1543e23e5 254 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 142:54d1543e23e5 255 if ( ppp.online == 0 ) {
nixnax 142:54d1543e23e5 256 if (ch == 0x7E) {
nixnax 142:54d1543e23e5 257 ppp.online = 1;
nixnax 142:54d1543e23e5 258 }
nixnax 142:54d1543e23e5 259 }
nixnax 142:54d1543e23e5 260 ppp.rx.head = hd; // update head pointer
nixnax 142:54d1543e23e5 261 ppp.rx.buflevel++;
nixnax 142:54d1543e23e5 262 }
nixnax 142:54d1543e23e5 263 }
nixnax 142:54d1543e23e5 264
nixnax 142:54d1543e23e5 265 /// print to debug port while checking for incoming characters
nixnax 142:54d1543e23e5 266 void putcWhileCheckingInput( char outByte )
nixnax 142:54d1543e23e5 267 {
nixnax 142:54d1543e23e5 268 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 269 checkPc();
nixnax 142:54d1543e23e5 270 debugPutc( outByte );
nixnax 142:54d1543e23e5 271 checkPc();
nixnax 142:54d1543e23e5 272 #endif
nixnax 142:54d1543e23e5 273 }
nixnax 142:54d1543e23e5 274
nixnax 142:54d1543e23e5 275 /// puts to debug port while checking the PPP input stream
nixnax 142:54d1543e23e5 276 void putsWhileCheckingInput( char * data )
nixnax 142:54d1543e23e5 277 {
nixnax 142:54d1543e23e5 278 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 279 char * nextChar = data;
nixnax 142:54d1543e23e5 280 while( *nextChar != 0 ) {
nixnax 142:54d1543e23e5 281 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 142:54d1543e23e5 282 nextChar++;
nixnax 142:54d1543e23e5 283 }
nixnax 142:54d1543e23e5 284 #endif
nixnax 142:54d1543e23e5 285 }
nixnax 142:54d1543e23e5 286
nixnax 145:098b6ed2f7f2 287 /// Initialize the PPP FCS (frame check sequence) total
nixnax 145:098b6ed2f7f2 288 void fcsReset()
nixnax 142:54d1543e23e5 289 {
nixnax 145:098b6ed2f7f2 290 ppp.fcs=0xffff; // crc restart
nixnax 142:54d1543e23e5 291 }
nixnax 142:54d1543e23e5 292
nixnax 145:098b6ed2f7f2 293 /// update the cumulative PPP FCS (frame check sequence)
nixnax 145:098b6ed2f7f2 294 void fcsDo(int x)
nixnax 142:54d1543e23e5 295 {
nixnax 142:54d1543e23e5 296 for (int i=0; i<8; i++) {
nixnax 145:098b6ed2f7f2 297 ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1; // crc calculator
nixnax 142:54d1543e23e5 298 x>>=1;
nixnax 142:54d1543e23e5 299 }
nixnax 142:54d1543e23e5 300 checkPc(); // handle input
nixnax 142:54d1543e23e5 301 }
nixnax 142:54d1543e23e5 302
nixnax 145:098b6ed2f7f2 303 /// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax 145:098b6ed2f7f2 304 int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax 142:54d1543e23e5 305 {
nixnax 145:098b6ed2f7f2 306 fcsReset();
nixnax 145:098b6ed2f7f2 307 for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax 145:098b6ed2f7f2 308 return ppp.fcs;
nixnax 142:54d1543e23e5 309 }
nixnax 142:54d1543e23e5 310
nixnax 142:54d1543e23e5 311 /// Get one character from our received PPP buffer
nixnax 142:54d1543e23e5 312 int pc_getBuf()
nixnax 142:54d1543e23e5 313 {
nixnax 142:54d1543e23e5 314 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 142:54d1543e23e5 315 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 142:54d1543e23e5 316 ppp.rx.buflevel--;
nixnax 142:54d1543e23e5 317 return x;
nixnax 142:54d1543e23e5 318 }
nixnax 142:54d1543e23e5 319
nixnax 142:54d1543e23e5 320 /// Dump a PPP frame to the debug serial port
nixnax 142:54d1543e23e5 321 /// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 142:54d1543e23e5 322 /// Capture the frame's hex output in your terminal program and save as a text file
nixnax 164:c3de3d212c4b 323 /// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax 142:54d1543e23e5 324 void dumpPPPFrame()
nixnax 142:54d1543e23e5 325 {
nixnax 142:54d1543e23e5 326 char pbuf[30];
nixnax 142:54d1543e23e5 327 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 328 checkPc();
nixnax 142:54d1543e23e5 329 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 142:54d1543e23e5 330 checkPc();
nixnax 142:54d1543e23e5 331 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 332 }
nixnax 142:54d1543e23e5 333 checkPc();
nixnax 142:54d1543e23e5 334 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 142:54d1543e23e5 335 checkPc();
nixnax 142:54d1543e23e5 336 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 337 }
nixnax 142:54d1543e23e5 338
nixnax 142:54d1543e23e5 339 /// Process a received PPP frame
nixnax 142:54d1543e23e5 340 void processPPPFrame(int start, int end)
nixnax 142:54d1543e23e5 341 {
nixnax 142:54d1543e23e5 342 led1Toggle(); // change led1 state on every frame we receive
nixnax 142:54d1543e23e5 343 if(start==end) {
nixnax 142:54d1543e23e5 344 return; // empty frame
nixnax 142:54d1543e23e5 345 }
nixnax 145:098b6ed2f7f2 346 fcsReset();
nixnax 142:54d1543e23e5 347 char * dest = ppp.pkt.buf;
nixnax 142:54d1543e23e5 348 ppp.pkt.len=0;
nixnax 142:54d1543e23e5 349 int unstuff=0;
nixnax 142:54d1543e23e5 350 int idx = start;
nixnax 142:54d1543e23e5 351 while(1) {
nixnax 142:54d1543e23e5 352 checkPc();
nixnax 142:54d1543e23e5 353 if (unstuff==0) {
nixnax 142:54d1543e23e5 354 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 142:54d1543e23e5 355 else {
nixnax 142:54d1543e23e5 356 *dest = ppp.rx.buf[idx];
nixnax 142:54d1543e23e5 357 ppp.pkt.len++;
nixnax 142:54d1543e23e5 358 dest++;
nixnax 145:098b6ed2f7f2 359 fcsDo(ppp.rx.buf[idx]);
nixnax 142:54d1543e23e5 360 }
nixnax 142:54d1543e23e5 361 } else { // unstuff characters prefixed with 0x7d
nixnax 142:54d1543e23e5 362 *dest = ppp.rx.buf[idx]^0x20;
nixnax 142:54d1543e23e5 363 ppp.pkt.len++;
nixnax 142:54d1543e23e5 364 dest++;
nixnax 145:098b6ed2f7f2 365 fcsDo(ppp.rx.buf[idx]^0x20);
nixnax 142:54d1543e23e5 366 unstuff=0;
nixnax 142:54d1543e23e5 367 }
nixnax 142:54d1543e23e5 368 idx = (idx+1) & (RXBUFLEN-1);
nixnax 142:54d1543e23e5 369 if (idx == end) break;
nixnax 142:54d1543e23e5 370 }
nixnax 145:098b6ed2f7f2 371 ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax 142:54d1543e23e5 372 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 142:54d1543e23e5 373 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 142:54d1543e23e5 374 determinePacketType();
nixnax 142:54d1543e23e5 375 } else {
nixnax 142:54d1543e23e5 376 #define REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 377 #ifdef REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 378 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 379 checkPc();
nixnax 142:54d1543e23e5 380 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 142:54d1543e23e5 381 checkPc();
nixnax 142:54d1543e23e5 382 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 383 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 142:54d1543e23e5 384 #endif
nixnax 142:54d1543e23e5 385 }
nixnax 142:54d1543e23e5 386 }
nixnax 142:54d1543e23e5 387
nixnax 142:54d1543e23e5 388 /// output a character to the PPP port while checking for incoming characters
nixnax 142:54d1543e23e5 389 void pcPutcWhileCheckingInput(int ch)
nixnax 142:54d1543e23e5 390 {
nixnax 142:54d1543e23e5 391 checkPc(); // check input
nixnax 142:54d1543e23e5 392 pc.putc(ch);
nixnax 142:54d1543e23e5 393 checkPc();
nixnax 142:54d1543e23e5 394 }
nixnax 142:54d1543e23e5 395
nixnax 142:54d1543e23e5 396 /// do PPP HDLC-like handling of special (flag) characters
nixnax 143:c5019f856a56 397 void hdlcPut(int ch)
nixnax 142:54d1543e23e5 398 {
nixnax 142:54d1543e23e5 399 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 142:54d1543e23e5 400 pcPutcWhileCheckingInput(0x7d);
nixnax 142:54d1543e23e5 401 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 142:54d1543e23e5 402 } else {
nixnax 142:54d1543e23e5 403 pcPutcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 404 }
nixnax 142:54d1543e23e5 405 }
nixnax 142:54d1543e23e5 406
nixnax 142:54d1543e23e5 407 /// send a PPP frame in HDLC format
nixnax 144:01d98cf7738e 408 void sendPppFrame()
nixnax 143:c5019f856a56 409 {
nixnax 145:098b6ed2f7f2 410 int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 142:54d1543e23e5 411 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 142:54d1543e23e5 412 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 142:54d1543e23e5 413 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 142:54d1543e23e5 414 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 415 wait_us(86); // wait one character time
nixnax 142:54d1543e23e5 416 checkPc();
nixnax 142:54d1543e23e5 417 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 142:54d1543e23e5 418 }
nixnax 142:54d1543e23e5 419 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 142:54d1543e23e5 420 }
nixnax 142:54d1543e23e5 421
nixnax 143:c5019f856a56 422 /// 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 423 int bufferToIP(char * buffer)
nixnax 143:c5019f856a56 424 {
nixnax 143:c5019f856a56 425 int result=0;
nixnax 143:c5019f856a56 426 for(int i=0; i<4; i++) result = (result<<8)|(*buffer++ & 0xff);
nixnax 143:c5019f856a56 427 return result;
nixnax 143:c5019f856a56 428 }
nixnax 143:c5019f856a56 429
nixnax 142:54d1543e23e5 430 /// handle IPCP configuration requests
nixnax 142:54d1543e23e5 431 void ipcpConfigRequestHandler()
nixnax 142:54d1543e23e5 432 {
nixnax 142:54d1543e23e5 433 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 143:c5019f856a56 434 if(ppp.pkt.buf[8]==3) {
nixnax 143:c5019f856a56 435 ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax 143:c5019f856a56 436 debugPrintf("Host IP = %d.%d.%d.%d (%08x)\n", ppp.pkt.buf[10],ppp.pkt.buf[11],ppp.pkt.buf[12],ppp.pkt.buf[13],ppp.hostIP);
nixnax 143:c5019f856a56 437 }
nixnax 143:c5019f856a56 438
nixnax 167:ff8a2d8beeb1 439 ppp.ipcp->code=2; // change code to ack
nixnax 144:01d98cf7738e 440 sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 142:54d1543e23e5 441
nixnax 142:54d1543e23e5 442 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 167:ff8a2d8beeb1 443 ppp.ipcp->code=1; // change code to request
nixnax 167:ff8a2d8beeb1 444 ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax 167:ff8a2d8beeb1 445 ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 144:01d98cf7738e 446 sendPppFrame(); // send our request
nixnax 142:54d1543e23e5 447 }
nixnax 142:54d1543e23e5 448
nixnax 142:54d1543e23e5 449 /// handle IPCP acknowledge (do nothing)
nixnax 142:54d1543e23e5 450 void ipcpAckHandler()
nixnax 142:54d1543e23e5 451 {
nixnax 142:54d1543e23e5 452 debugPrintf("Their IPCP Grant\n");
nixnax 142:54d1543e23e5 453 }
nixnax 142:54d1543e23e5 454
nixnax 143:c5019f856a56 455 /// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax 143:c5019f856a56 456 /// 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 457 void ipcpNackHandler()
nixnax 142:54d1543e23e5 458 {
nixnax 146:a45f49a2b29c 459 debugPrintf("Their IPCP Nack\n");
nixnax 142:54d1543e23e5 460 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 167:ff8a2d8beeb1 461 ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax 144:01d98cf7738e 462 sendPppFrame(); // let's request this IP address as ours
nixnax 143:c5019f856a56 463 debugPrintf("Our IPCP ACK (received an IP)\n");
nixnax 146:a45f49a2b29c 464 } else { // if it's not an IP nack we ignore it
nixnax 146:a45f49a2b29c 465 debugPrintf("IPCP Nack Ignored\n");
nixnax 146:a45f49a2b29c 466 }
nixnax 142:54d1543e23e5 467 }
nixnax 142:54d1543e23e5 468
nixnax 142:54d1543e23e5 469 /// handle all other IPCP requests (by ignoring them)
nixnax 142:54d1543e23e5 470 void ipcpDefaultHandler()
nixnax 142:54d1543e23e5 471 {
nixnax 142:54d1543e23e5 472 debugPrintf("Their IPCP Other\n");
nixnax 142:54d1543e23e5 473 }
nixnax 142:54d1543e23e5 474
nixnax 142:54d1543e23e5 475 /// process an incoming IPCP packet
nixnax 142:54d1543e23e5 476 void IPCPframe()
nixnax 142:54d1543e23e5 477 {
nixnax 167:ff8a2d8beeb1 478 int action = ppp.ipcp->code; // packet type is here
nixnax 167:ff8a2d8beeb1 479 switch (action) {
nixnax 142:54d1543e23e5 480 case 1:
nixnax 142:54d1543e23e5 481 ipcpConfigRequestHandler();
nixnax 142:54d1543e23e5 482 break;
nixnax 142:54d1543e23e5 483 case 2:
nixnax 142:54d1543e23e5 484 ipcpAckHandler();
nixnax 142:54d1543e23e5 485 break;
nixnax 142:54d1543e23e5 486 case 3:
nixnax 142:54d1543e23e5 487 ipcpNackHandler();
nixnax 142:54d1543e23e5 488 break;
nixnax 142:54d1543e23e5 489 default:
nixnax 142:54d1543e23e5 490 ipcpDefaultHandler();
nixnax 142:54d1543e23e5 491 }
nixnax 142:54d1543e23e5 492 }
nixnax 142:54d1543e23e5 493
nixnax 142:54d1543e23e5 494 /// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax 161:d59f778bc8ab 495 unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax 142:54d1543e23e5 496 {
nixnax 159:4d1bf96a59cd 497 unsigned int i,hi,lo;
nixnax 142:54d1543e23e5 498 unsigned char placeHolder;
nixnax 161:d59f778bc8ab 499 if (restart) ppp.sum=0;
nixnax 142:54d1543e23e5 500 if (len&1) {
nixnax 142:54d1543e23e5 501 placeHolder = ptr[len];
nixnax 142:54d1543e23e5 502 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 503 }
nixnax 142:54d1543e23e5 504 i=0;
nixnax 142:54d1543e23e5 505 while ( i<len ) {
nixnax 142:54d1543e23e5 506 checkPc();
nixnax 142:54d1543e23e5 507 hi = ptr[i++];
nixnax 142:54d1543e23e5 508 lo = ptr[i++];
nixnax 159:4d1bf96a59cd 509 ppp.sum = ppp.sum + ((hi<<8)|lo);
nixnax 142:54d1543e23e5 510 }
nixnax 142:54d1543e23e5 511 if (len&1) {
nixnax 142:54d1543e23e5 512 ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax 142:54d1543e23e5 513 }
nixnax 159:4d1bf96a59cd 514 ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax 159:4d1bf96a59cd 515 ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax 159:4d1bf96a59cd 516 return ~ppp.sum;
nixnax 142:54d1543e23e5 517 }
nixnax 142:54d1543e23e5 518
nixnax 142:54d1543e23e5 519 /// perform the checksum on an IP header
nixnax 146:a45f49a2b29c 520 void IpHeaderCheckSum()
nixnax 142:54d1543e23e5 521 {
nixnax 161:d59f778bc8ab 522 ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax 161:d59f778bc8ab 523 int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax 161:d59f778bc8ab 524 unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax 161:d59f778bc8ab 525 ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax 146:a45f49a2b29c 526 }
nixnax 146:a45f49a2b29c 527
nixnax 147:0f40005cbc5f 528 /// swap the IP source and destination addresses
nixnax 147:0f40005cbc5f 529 void swapIpAddresses()
nixnax 147:0f40005cbc5f 530 {
nixnax 162:594729c0e5c1 531 unsigned int tempHold;
nixnax 162:594729c0e5c1 532 tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax 162:594729c0e5c1 533 ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax 162:594729c0e5c1 534 ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax 147:0f40005cbc5f 535 }
nixnax 147:0f40005cbc5f 536
nixnax 149:969d98f6fb88 537 /// swap the IP source and destination ports
nixnax 149:969d98f6fb88 538 void swapIpPorts()
nixnax 149:969d98f6fb88 539 {
nixnax 149:969d98f6fb88 540 int headerSizeIP = 4*(ppp.pkt.buf[4]&0xf); // calculate size of IP header
nixnax 149:969d98f6fb88 541 char * ipSrcPort = 4 + ppp.pkt.buf + headerSizeIP + 0; // ip source port location
nixnax 149:969d98f6fb88 542 char * ipDstPort = 4 + ppp.pkt.buf + headerSizeIP + 2; // ip destin port location
nixnax 149:969d98f6fb88 543 char tempHold[2];
nixnax 149:969d98f6fb88 544 memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax 149:969d98f6fb88 545 memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax 149:969d98f6fb88 546 memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax 149:969d98f6fb88 547 }
nixnax 149:969d98f6fb88 548
nixnax 170:3d3b2126181c 549 /// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax 170:3d3b2126181c 550 void checkSumPseudoHeader( unsigned int packetLength )
nixnax 170:3d3b2126181c 551 {
nixnax 170:3d3b2126181c 552 // 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 553 pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax 170:3d3b2126181c 554 pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax 170:3d3b2126181c 555 pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax 170:3d3b2126181c 556 pseudoHeader.zero = 0; // zero byte
nixnax 170:3d3b2126181c 557 pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax 170:3d3b2126181c 558 pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax 170:3d3b2126181c 559 dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax 170:3d3b2126181c 560 }
nixnax 170:3d3b2126181c 561
nixnax 171:46b36d4edd1d 562 /// initialize an IP packet to send
nixnax 171:46b36d4edd1d 563 void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax 171:46b36d4edd1d 564 {
nixnax 171:46b36d4edd1d 565 ppp.ppp->address = 0xff;
nixnax 171:46b36d4edd1d 566 ppp.ppp->control = 3;
nixnax 171:46b36d4edd1d 567 ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax 171:46b36d4edd1d 568 ppp.ip->version = 4;
nixnax 171:46b36d4edd1d 569 ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax 171:46b36d4edd1d 570 ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax 171:46b36d4edd1d 571 ppp.ip->dontFragment=1;
nixnax 171:46b36d4edd1d 572 ppp.ip->ttl=128;
nixnax 171:46b36d4edd1d 573 ppp.ip->protocol = protocol; // udp
nixnax 171:46b36d4edd1d 574 ppp.ip->srcAdrR = __REV(srcIp);
nixnax 171:46b36d4edd1d 575 ppp.ip->dstAdrR = __REV(dstIp);
nixnax 171:46b36d4edd1d 576 ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax 171:46b36d4edd1d 577 ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax 171:46b36d4edd1d 578 ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax 171:46b36d4edd1d 579 }
nixnax 171:46b36d4edd1d 580
nixnax 171:46b36d4edd1d 581
nixnax 171:46b36d4edd1d 582 /// Build a UDP packet from scratch
nixnax 171:46b36d4edd1d 583 void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax 171:46b36d4edd1d 584 {
nixnax 171:46b36d4edd1d 585 struct {
nixnax 171:46b36d4edd1d 586 unsigned int ipAll; // length of entire ip packet
nixnax 171:46b36d4edd1d 587 unsigned int ipHeader; // length of ip header
nixnax 171:46b36d4edd1d 588 unsigned int udpAll; // length of entire udp packet
nixnax 171:46b36d4edd1d 589 unsigned int udpData; // length of udp data segment
nixnax 171:46b36d4edd1d 590 } len;
nixnax 171:46b36d4edd1d 591 len.ipHeader = 20; // ip header length
nixnax 171:46b36d4edd1d 592 len.udpData = msgLen; // udp data size
nixnax 171:46b36d4edd1d 593 len.udpAll = len.udpData+8; // update local udp packet length
nixnax 171:46b36d4edd1d 594 len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax 171:46b36d4edd1d 595 initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax 171:46b36d4edd1d 596 ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax 171:46b36d4edd1d 597 ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax 171:46b36d4edd1d 598 memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax 171:46b36d4edd1d 599 ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax 171:46b36d4edd1d 600 ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax 171:46b36d4edd1d 601 IpHeaderCheckSum(); // refresh IP header checksum
nixnax 171:46b36d4edd1d 602 checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax 171:46b36d4edd1d 603 ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 171:46b36d4edd1d 604 unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax 171:46b36d4edd1d 605 ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 171:46b36d4edd1d 606 ppp.responseCounter++; // count UDP packet as a response
nixnax 171:46b36d4edd1d 607 sendPppFrame(); // send the UDP message back
nixnax 171:46b36d4edd1d 608 }
nixnax 171:46b36d4edd1d 609
nixnax 146:a45f49a2b29c 610 /// Process an incoming UDP packet.
nixnax 146:a45f49a2b29c 611 /// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax 146:a45f49a2b29c 612 void UDPpacket()
nixnax 146:a45f49a2b29c 613 {
nixnax 163:d1b4328e9f08 614 struct {
nixnax 163:d1b4328e9f08 615 unsigned int all; // length of entire ip packet
nixnax 163:d1b4328e9f08 616 unsigned int header; // length of ip header
nixnax 163:d1b4328e9f08 617 } ipLength;
nixnax 163:d1b4328e9f08 618
nixnax 163:d1b4328e9f08 619 struct {
nixnax 165:c47826d07e0d 620 unsigned int all; // length of entire udp packet
nixnax 163:d1b4328e9f08 621 unsigned int data; // length of udp data segment
nixnax 163:d1b4328e9f08 622 } udpLength;
nixnax 163:d1b4328e9f08 623
nixnax 163:d1b4328e9f08 624 ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax 163:d1b4328e9f08 625 ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax 171:46b36d4edd1d 626 udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax 163:d1b4328e9f08 627 udpLength.data = udpLength.all - 8; // size of udp data
nixnax 147:0f40005cbc5f 628
nixnax 146:a45f49a2b29c 629 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 171:46b36d4edd1d 630 char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax 171:46b36d4edd1d 631 char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax 163:d1b4328e9f08 632
nixnax 171:46b36d4edd1d 633 unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax 171:46b36d4edd1d 634 unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax 163:d1b4328e9f08 635
nixnax 163:d1b4328e9f08 636 if(v0) {
nixnax 163:d1b4328e9f08 637 debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax 163:d1b4328e9f08 638 debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax 163:d1b4328e9f08 639 debugPrintf("Len %03d", udpLength);
nixnax 163:d1b4328e9f08 640 }
nixnax 146:a45f49a2b29c 641 if (v1) {
nixnax 163:d1b4328e9f08 642 int printSize = udpLength.data;
nixnax 146:a45f49a2b29c 643 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 146:a45f49a2b29c 644 for (int i=0; i<printSize; i++) {
nixnax 163:d1b4328e9f08 645 char ch = ppp.udp->data[i];
nixnax 146:a45f49a2b29c 646 if (ch>31 && ch<127) {
nixnax 146:a45f49a2b29c 647 debugPrintf("%c", ch);
nixnax 146:a45f49a2b29c 648 } else {
nixnax 146:a45f49a2b29c 649 debugPrintf("_");
nixnax 146:a45f49a2b29c 650 }
nixnax 146:a45f49a2b29c 651 }
nixnax 146:a45f49a2b29c 652 }
nixnax 146:a45f49a2b29c 653 if (v0) debugPrintf("\n");
nixnax 146:a45f49a2b29c 654 #endif
nixnax 163:d1b4328e9f08 655 int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax 163:d1b4328e9f08 656 int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax 146:a45f49a2b29c 657 if ( (echoFound) || (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax 146:a45f49a2b29c 658 if (echoFound) {
nixnax 171:46b36d4edd1d 659 swapIpAddresses(); // swap IP source and destination
nixnax 171:46b36d4edd1d 660 swapIpPorts(); // swap IP source and destination ports
nixnax 163:d1b4328e9f08 661 memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax 170:3d3b2126181c 662 int n=0;
nixnax 170:3d3b2126181c 663 n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax 168:c77eb908042a 664 udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax 171:46b36d4edd1d 665 // we may have changed data length, update all the lengths
nixnax 171:46b36d4edd1d 666 udpLength.all = udpLength.data+8; // update local udp packet length
nixnax 171:46b36d4edd1d 667 ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax 171:46b36d4edd1d 668 ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax 171:46b36d4edd1d 669 ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax 171:46b36d4edd1d 670 ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax 171:46b36d4edd1d 671 IpHeaderCheckSum(); // refresh IP header checksum
nixnax 171:46b36d4edd1d 672 checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax 171:46b36d4edd1d 673 ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 171:46b36d4edd1d 674 unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax 171:46b36d4edd1d 675 ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 171:46b36d4edd1d 676 ppp.responseCounter++; // count UDP packet as a response
nixnax 171:46b36d4edd1d 677 sendPppFrame(); // send the UDP message back
nixnax 171:46b36d4edd1d 678 } else if ( testFound ) {
nixnax 171:46b36d4edd1d 679 unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax 171:46b36d4edd1d 680 unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax 171:46b36d4edd1d 681 unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax 171:46b36d4edd1d 682 unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax 171:46b36d4edd1d 683 int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter++);
nixnax 171:46b36d4edd1d 684 sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax 146:a45f49a2b29c 685 }
nixnax 146:a45f49a2b29c 686 }
nixnax 142:54d1543e23e5 687 }
nixnax 142:54d1543e23e5 688
nixnax 142:54d1543e23e5 689 /// handle a PING ICMP (internet control message protocol) packet
nixnax 142:54d1543e23e5 690 void ICMPpacket() // internet control message protocol
nixnax 142:54d1543e23e5 691 {
nixnax 165:c47826d07e0d 692 struct {
nixnax 165:c47826d07e0d 693 unsigned int all; // length of entire ip packet
nixnax 165:c47826d07e0d 694 unsigned int header; // length of ip header
nixnax 165:c47826d07e0d 695 } ipLength;
nixnax 165:c47826d07e0d 696 struct {
nixnax 165:c47826d07e0d 697 unsigned int all; // length of entire udp packet
nixnax 165:c47826d07e0d 698 unsigned int data; // length of udp data segment
nixnax 165:c47826d07e0d 699 } icmpLength;
nixnax 165:c47826d07e0d 700 ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax 165:c47826d07e0d 701 ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax 165:c47826d07e0d 702 ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax 165:c47826d07e0d 703 icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax 165:c47826d07e0d 704 icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax 142:54d1543e23e5 705 #define ICMP_TYPE_PING_REQUEST 8
nixnax 165:c47826d07e0d 706 if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax 165:c47826d07e0d 707 ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax 147:0f40005cbc5f 708 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 167:ff8a2d8beeb1 709 char * srcAdr = ppp.ip->srcAdrPtr;
nixnax 167:ff8a2d8beeb1 710 char * dstAdr = ppp.ip->dstAdrPtr;
nixnax 165:c47826d07e0d 711 int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax 165:c47826d07e0d 712 int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax 142:54d1543e23e5 713 if(1) {
nixnax 142:54d1543e23e5 714 char pbuf[50];
nixnax 142:54d1543e23e5 715 checkPc();
nixnax 142:54d1543e23e5 716 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 717 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 718 checkPc();
nixnax 142:54d1543e23e5 719 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 142:54d1543e23e5 720 checkPc();
nixnax 142:54d1543e23e5 721 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 722 }
nixnax 142:54d1543e23e5 723 #endif
nixnax 147:0f40005cbc5f 724 swapIpAddresses(); // swap the IP source and destination addresses
nixnax 147:0f40005cbc5f 725 IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax 142:54d1543e23e5 726 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 165:c47826d07e0d 727 ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 165:c47826d07e0d 728 ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax 165:c47826d07e0d 729 unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax 165:c47826d07e0d 730 ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax 142:54d1543e23e5 731
nixnax 165:c47826d07e0d 732 int printSize = icmpLength.data; // exclude size of icmp header
nixnax 142:54d1543e23e5 733 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 142:54d1543e23e5 734 if (0) {
nixnax 142:54d1543e23e5 735 for (int i=0; i<printSize; i++) {
nixnax 165:c47826d07e0d 736 char ch = ppp.icmp->data[i];
nixnax 142:54d1543e23e5 737 if (ch>31 && ch<127) {
nixnax 142:54d1543e23e5 738 putcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 739 } else {
nixnax 142:54d1543e23e5 740 putcWhileCheckingInput('_');
nixnax 142:54d1543e23e5 741 }
nixnax 142:54d1543e23e5 742 }
nixnax 142:54d1543e23e5 743 putcWhileCheckingInput('\n');
nixnax 142:54d1543e23e5 744 }
nixnax 165:c47826d07e0d 745 ppp.responseCounter++; // count a ping as a response
nixnax 144:01d98cf7738e 746 sendPppFrame(); // reply to the ping
nixnax 142:54d1543e23e5 747 } else {
nixnax 142:54d1543e23e5 748 if (v0) {
nixnax 165:c47826d07e0d 749 debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax 142:54d1543e23e5 750 }
nixnax 142:54d1543e23e5 751 }
nixnax 142:54d1543e23e5 752 }
nixnax 142:54d1543e23e5 753
nixnax 142:54d1543e23e5 754 /// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax 142:54d1543e23e5 755 void IGMPpacket()
nixnax 142:54d1543e23e5 756 {
nixnax 142:54d1543e23e5 757 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 142:54d1543e23e5 758 }
nixnax 142:54d1543e23e5 759
nixnax 142:54d1543e23e5 760 /// dump the header of an IP pakcet on the (optional) debug serial port
nixnax 142:54d1543e23e5 761 void dumpHeaderIP (int outGoing)
nixnax 142:54d1543e23e5 762 {
nixnax 142:54d1543e23e5 763 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 142:54d1543e23e5 764 checkPc(); // we are expecting the first character of the next packet
nixnax 155:9c6a1d249e26 765 int IPv4Id = __REV16(ppp.ip->identR);
nixnax 152:025c73b6c0a9 766 char pbuf[80]; // local print buffer
nixnax 142:54d1543e23e5 767 int n=0;
nixnax 142:54d1543e23e5 768 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 142:54d1543e23e5 769 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 770 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 142:54d1543e23e5 771 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 167:ff8a2d8beeb1 772 char * srcAdr = ppp.ip->srcAdrPtr;
nixnax 167:ff8a2d8beeb1 773 char * dstAdr = ppp.ip->dstAdrPtr;
nixnax 142:54d1543e23e5 774 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 775 #endif
nixnax 142:54d1543e23e5 776 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 777 #ifndef TCP_HEADER_DUMP_YES
nixnax 160:bd701ad564cb 778 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 779 #endif
nixnax 142:54d1543e23e5 780 #endif
nixnax 142:54d1543e23e5 781 }
nixnax 142:54d1543e23e5 782
nixnax 142:54d1543e23e5 783 /// dump a TCP header on the optional debug serial port
nixnax 142:54d1543e23e5 784 void dumpHeaderTCP(int outGoing)
nixnax 142:54d1543e23e5 785 {
nixnax 142:54d1543e23e5 786 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 155:9c6a1d249e26 787 char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax 142:54d1543e23e5 788 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 142:54d1543e23e5 789 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 155:9c6a1d249e26 790 memset(flagString,'.', 8); // fill string with "........"
nixnax 156:163c23249731 791 if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax 156:163c23249731 792 if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax 156:163c23249731 793 if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax 156:163c23249731 794 if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax 156:163c23249731 795 if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax 156:163c23249731 796 if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax 156:163c23249731 797 if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax 156:163c23249731 798 if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax 155:9c6a1d249e26 799 flagString[8]=0; // null terminate string
nixnax 142:54d1543e23e5 800 #else
nixnax 156:163c23249731 801 if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax 156:163c23249731 802 if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax 156:163c23249731 803 if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax 156:163c23249731 804 if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax 156:163c23249731 805 if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax 155:9c6a1d249e26 806 flagString[1]=0; // null terminate string
nixnax 142:54d1543e23e5 807 #endif
nixnax 155:9c6a1d249e26 808 putsWhileCheckingInput( flagString );
nixnax 142:54d1543e23e5 809 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 810 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 811 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 160:bd701ad564cb 812 #else
nixnax 160:bd701ad564cb 813 putsWhileCheckingInput("\x1b[30m"); // write a black color after every packet
nixnax 142:54d1543e23e5 814 #endif
nixnax 156:163c23249731 815 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 816 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax 142:54d1543e23e5 817 }
nixnax 142:54d1543e23e5 818 #endif
nixnax 142:54d1543e23e5 819 }
nixnax 142:54d1543e23e5 820
nixnax 143:c5019f856a56 821 /// Encode a buffer in base-64
nixnax 142:54d1543e23e5 822 void enc64(char * in, char * out, int len)
nixnax 142:54d1543e23e5 823 {
nixnax 142:54d1543e23e5 824 const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax 142:54d1543e23e5 825 int i,j,a,b,c;
nixnax 142:54d1543e23e5 826 i=0;
nixnax 142:54d1543e23e5 827 j=0;
nixnax 142:54d1543e23e5 828 while(1) {
nixnax 142:54d1543e23e5 829 if (i<len) {
nixnax 142:54d1543e23e5 830 a = in[i++];
nixnax 142:54d1543e23e5 831 out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax 142:54d1543e23e5 832 } else break;
nixnax 142:54d1543e23e5 833 if (i<len) {
nixnax 142:54d1543e23e5 834 b = in[i++];
nixnax 142:54d1543e23e5 835 out[j++] = lut[ ( (a << 4) & 0x30) | ( (b >> 4) & 0x0f) ];
nixnax 142:54d1543e23e5 836 out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax 142:54d1543e23e5 837 } else out[j++] = '=';
nixnax 142:54d1543e23e5 838 if (i<len) {
nixnax 142:54d1543e23e5 839 c = in[i++];
nixnax 142:54d1543e23e5 840 j--;
nixnax 142:54d1543e23e5 841 out[j++] = lut[ ( (b << 2) & 0x3c) | ( (c >> 6) & 0x03) ];
nixnax 142:54d1543e23e5 842 out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax 142:54d1543e23e5 843 } else out[j++] = '=';
nixnax 142:54d1543e23e5 844 }
nixnax 142:54d1543e23e5 845 out[j]=0;
nixnax 142:54d1543e23e5 846 }
nixnax 142:54d1543e23e5 847
nixnax 160:bd701ad564cb 848 /// Handle a request for an http websocket.
nixnax 160:bd701ad564cb 849 /// 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 850 int webSocketHandler(char * dataStart)
nixnax 142:54d1543e23e5 851 {
nixnax 142:54d1543e23e5 852 int n=0; // byte counter
nixnax 142:54d1543e23e5 853 char * key = strstr(dataStart, "Sec-WebSocket-Key: "); // search for the key in the payload
nixnax 142:54d1543e23e5 854 if (key != NULL) {
nixnax 142:54d1543e23e5 855 if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax 142:54d1543e23e5 856 char challenge [70];
nixnax 142:54d1543e23e5 857 strncpy(challenge,key+19,70); // a local buffer
nixnax 142:54d1543e23e5 858 *strchr(challenge,'\r')=0; // insert null so we can use sprintf
nixnax 142:54d1543e23e5 859 strncat(challenge,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11",70); // append websocket gui code
nixnax 142:54d1543e23e5 860 char shaOutput [20]; // sha1 output
nixnax 142:54d1543e23e5 861 sha1( shaOutput, challenge, strlen(challenge));
nixnax 142:54d1543e23e5 862 char encOut[50];
nixnax 142:54d1543e23e5 863 enc64( shaOutput, encOut, 20);
nixnax 142:54d1543e23e5 864 char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax 142:54d1543e23e5 865 char * version = challenge;
nixnax 142:54d1543e23e5 866 strncpy(version, versionstring,70); // copy version string
nixnax 142:54d1543e23e5 867 *strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax 142:54d1543e23e5 868 memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax 142:54d1543e23e5 869 n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax 142:54d1543e23e5 870 n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax 142:54d1543e23e5 871 n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax 142:54d1543e23e5 872 n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax 142:54d1543e23e5 873 n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax 142:54d1543e23e5 874 n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax 142:54d1543e23e5 875 n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax 142:54d1543e23e5 876 }
nixnax 142:54d1543e23e5 877 return n; // this response should satisfy a web browser's websocket protocol request
nixnax 142:54d1543e23e5 878 }
nixnax 142:54d1543e23e5 879
nixnax 142:54d1543e23e5 880 #define TCP_FLAG_ACK (1<<4)
nixnax 142:54d1543e23e5 881 #define TCP_FLAG_SYN (1<<1)
nixnax 142:54d1543e23e5 882 #define TCP_FLAG_PSH (1<<3)
nixnax 142:54d1543e23e5 883 #define TCP_FLAG_RST (1<<2)
nixnax 142:54d1543e23e5 884 #define TCP_FLAG_FIN (1<<0)
nixnax 142:54d1543e23e5 885
nixnax 142:54d1543e23e5 886 /// respond to an HTTP request
nixnax 142:54d1543e23e5 887 int httpResponse(char * dataStart)
nixnax 142:54d1543e23e5 888 {
nixnax 142:54d1543e23e5 889 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 890 n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax 160:bd701ad564cb 891 if (n>0) return n; // if n>0 we already have a response, so return
nixnax 142:54d1543e23e5 892
nixnax 142:54d1543e23e5 893 int nHeader; // byte size of HTTP header
nixnax 142:54d1543e23e5 894 int contentLengthStart; // index where HTML starts
nixnax 142:54d1543e23e5 895 int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax 142:54d1543e23e5 896
nixnax 146:a45f49a2b29c 897 ppp.responseCounter++; // increment the number of frames we have made
nixnax 142:54d1543e23e5 898
nixnax 142:54d1543e23e5 899 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax 142:54d1543e23e5 900 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 901 httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 902 httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 903 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 142:54d1543e23e5 904 if( (httpGetRoot==0) || (httpGetx==0) ) {
nixnax 142:54d1543e23e5 905 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax 142:54d1543e23e5 906 } else {
nixnax 142:54d1543e23e5 907 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 142:54d1543e23e5 908 }
nixnax 142:54d1543e23e5 909 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 142:54d1543e23e5 910 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 142:54d1543e23e5 911 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 142:54d1543e23e5 912 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 142:54d1543e23e5 913 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 914 nHeader=n; // size of HTTP header
nixnax 142:54d1543e23e5 915 if( httpGetRoot == 0 ) {
nixnax 142:54d1543e23e5 916 // this is where we insert our web page into the buffer
nixnax 142:54d1543e23e5 917 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 142:54d1543e23e5 918 n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax 142:54d1543e23e5 919 } else if ( (httpGet5 == 'w') && (httpGet6 == 's') ) { // "ws" is a special page for websocket demo
nixnax 142:54d1543e23e5 920 memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax 142:54d1543e23e5 921 n = n + sizeof(webSocketPage)-1; // one less than size
nixnax 142:54d1543e23e5 922 } else {
nixnax 142:54d1543e23e5 923 if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax 142:54d1543e23e5 924
nixnax 142:54d1543e23e5 925 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 142:54d1543e23e5 926 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 142:54d1543e23e5 927 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 142:54d1543e23e5 928 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax 146:a45f49a2b29c 929 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax 142:54d1543e23e5 930 #else
nixnax 142:54d1543e23e5 931 if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax 167:ff8a2d8beeb1 932 n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax 142:54d1543e23e5 933 }
nixnax 142:54d1543e23e5 934 // /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax 146:a45f49a2b29c 935 n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax 142:54d1543e23e5 936 #endif
nixnax 142:54d1543e23e5 937 } else {
nixnax 142:54d1543e23e5 938 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 142:54d1543e23e5 939 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax 142:54d1543e23e5 940 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 142:54d1543e23e5 941 }
nixnax 142:54d1543e23e5 942 }
nixnax 142:54d1543e23e5 943 #define CONTENTLENGTHSIZE 5
nixnax 142:54d1543e23e5 944 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 142:54d1543e23e5 945 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 142:54d1543e23e5 946 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 142:54d1543e23e5 947 return n; // total byte size of our response
nixnax 142:54d1543e23e5 948 }
nixnax 142:54d1543e23e5 949
nixnax 160:bd701ad564cb 950 /// Handle TCP data that is not an HTTP GET.
nixnax 160:bd701ad564cb 951 /// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax 160:bd701ad564cb 952 /// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax 142:54d1543e23e5 953 int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax 142:54d1543e23e5 954 {
nixnax 142:54d1543e23e5 955 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 956 if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax 160:bd701ad564cb 957 char mask [4];
nixnax 160:bd701ad564cb 958 memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax 160:bd701ad564cb 959 int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax 160:bd701ad564cb 960 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 961 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 962 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 963 memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax 160:bd701ad564cb 964 n = len; // our response size remains exactly the same length as what we received
nixnax 142:54d1543e23e5 965 } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax 142:54d1543e23e5 966 n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax 142:54d1543e23e5 967 dataStart[1]=0; // we don't have mask bytes on
nixnax 160:bd701ad564cb 968 } else {
nixnax 160:bd701ad564cb 969 if (v1) putsWhileCheckingInput("TCP data received\n"); // all other tcp push packets
nixnax 163:d1b4328e9f08 970 }
nixnax 142:54d1543e23e5 971 return n; // total byte size of our response
nixnax 142:54d1543e23e5 972 }
nixnax 142:54d1543e23e5 973
nixnax 142:54d1543e23e5 974 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 975 /// 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 976 void tcpHandler()
nixnax 142:54d1543e23e5 977 {
nixnax 142:54d1543e23e5 978 // IP header
nixnax 154:18b2bd92f557 979 int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax 154:18b2bd92f557 980 int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax 142:54d1543e23e5 981
nixnax 142:54d1543e23e5 982 // TCP header
nixnax 160:bd701ad564cb 983
nixnax 155:9c6a1d249e26 984 ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax 154:18b2bd92f557 985 int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax 160:bd701ad564cb 986 char * tcp = ppp.ipStart+headerSizeIp; // calculate start of tcp packet
nixnax 142:54d1543e23e5 987
nixnax 154:18b2bd92f557 988 int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax 152:025c73b6c0a9 989
nixnax 154:18b2bd92f557 990 char * tcpDataIn = tcp + headerSizeTcp; // start of data block after TCP header
nixnax 154:18b2bd92f557 991 int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax 154:18b2bd92f557 992
nixnax 154:18b2bd92f557 993 unsigned int seq_in = __REV(ppp.tcp->seqTcpR);
nixnax 154:18b2bd92f557 994 unsigned int ack_in = __REV(ppp.tcp->ackTcpR);
nixnax 142:54d1543e23e5 995 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 142:54d1543e23e5 996 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 142:54d1543e23e5 997
nixnax 142:54d1543e23e5 998 // first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax 142:54d1543e23e5 999 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 154:18b2bd92f557 1000 headerSizeTcp = 20; // shorten outgoing TCP header size 20 bytes
nixnax 154:18b2bd92f557 1001 ppp.ip->headerLength = 5; // ip header is 20 bytes long
nixnax 154:18b2bd92f557 1002 ppp.tcp->offset = (headerSizeTcp/4);
nixnax 154:18b2bd92f557 1003 ppp.ip->lengthR = __REV(40);
nixnax 154:18b2bd92f557 1004 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 154:18b2bd92f557 1005
nixnax 154:18b2bd92f557 1006 ppp.ip->lengthR = __REV16(40);
nixnax 142:54d1543e23e5 1007
nixnax 142:54d1543e23e5 1008 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 142:54d1543e23e5 1009 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 155:9c6a1d249e26 1010 //int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 160:bd701ad564cb 1011
nixnax 159:4d1bf96a59cd 1012 ppp.tcp->windowR = __REV16( 700 ); // set tcp window size to 700 bytes
nixnax 142:54d1543e23e5 1013
nixnax 142:54d1543e23e5 1014 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 142:54d1543e23e5 1015
nixnax 156:163c23249731 1016 switch ( ppp.tcp->flag.All ) {
nixnax 158:841592aed956 1017 case TCP_FLAG_ACK: // handle ack messages by ignoring them
nixnax 142:54d1543e23e5 1018 return;
nixnax 142:54d1543e23e5 1019 case TCP_FLAG_SYN:
nixnax 142:54d1543e23e5 1020 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 142:54d1543e23e5 1021 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 142:54d1543e23e5 1022 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 1023 break;
nixnax 142:54d1543e23e5 1024 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 142:54d1543e23e5 1025 if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax 142:54d1543e23e5 1026 flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // set outgoing FIN flag to ask them to close from their side
nixnax 142:54d1543e23e5 1027 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 142:54d1543e23e5 1028 } else {
nixnax 158:841592aed956 1029 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax 142:54d1543e23e5 1030 }
nixnax 142:54d1543e23e5 1031 break;
nixnax 142:54d1543e23e5 1032 case TCP_FLAG_FIN:
nixnax 142:54d1543e23e5 1033 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1034 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1035 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 142:54d1543e23e5 1036 ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 1037 break;
nixnax 142:54d1543e23e5 1038 default:
nixnax 142:54d1543e23e5 1039 return; // ignore remaining packets
nixnax 142:54d1543e23e5 1040 } // switch
nixnax 142:54d1543e23e5 1041
nixnax 142:54d1543e23e5 1042 // The TCP flag handling is now done
nixnax 142:54d1543e23e5 1043 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 147:0f40005cbc5f 1044 swapIpAddresses(); // swap IP source and destination addresses
nixnax 149:969d98f6fb88 1045 swapIpPorts(); // swap IP source and destination ports
nixnax 142:54d1543e23e5 1046
nixnax 158:841592aed956 1047 ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax 158:841592aed956 1048 ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax 160:bd701ad564cb 1049
nixnax 156:163c23249731 1050 ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax 142:54d1543e23e5 1051
nixnax 159:4d1bf96a59cd 1052 // recalculate all the header sizes
nixnax 154:18b2bd92f557 1053 tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax 154:18b2bd92f557 1054 int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax 159:4d1bf96a59cd 1055 ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax 142:54d1543e23e5 1056 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 1057
nixnax 142:54d1543e23e5 1058 // the header is all set up, now do the IP and TCP checksums
nixnax 146:a45f49a2b29c 1059 IpHeaderCheckSum(); // calculate new IP header checksum
nixnax 170:3d3b2126181c 1060 checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax 159:4d1bf96a59cd 1061 ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax 161:d59f778bc8ab 1062 unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax 159:4d1bf96a59cd 1063 ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax 160:bd701ad564cb 1064
nixnax 170:3d3b2126181c 1065 dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax 170:3d3b2126181c 1066 dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax 171:46b36d4edd1d 1067
nixnax 142:54d1543e23e5 1068 for (int i=0; i<45*1000/10; i++) { // 45 ms delay before sending frame - a typical internet delay time
nixnax 142:54d1543e23e5 1069 checkPc(); // catch any incoming characters
nixnax 142:54d1543e23e5 1070 wait_us(10); // wait less than 1 character duration at 115200
nixnax 142:54d1543e23e5 1071 }
nixnax 144:01d98cf7738e 1072 sendPppFrame(); // All preparation complete - send the TCP response
nixnax 142:54d1543e23e5 1073 if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
nixnax 142:54d1543e23e5 1074 memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax 142:54d1543e23e5 1075 }
nixnax 142:54d1543e23e5 1076
nixnax 142:54d1543e23e5 1077 /// dump the TCP data to the debug serial port
nixnax 142:54d1543e23e5 1078 void dumpDataTCP()
nixnax 142:54d1543e23e5 1079 {
nixnax 142:54d1543e23e5 1080 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 142:54d1543e23e5 1081 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 154:18b2bd92f557 1082 int headerSizeTcp = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 154:18b2bd92f557 1083 int dataLen = ipPktLen - ipHeaderLen - headerSizeTcp; // data is what's left after the two headers
nixnax 142:54d1543e23e5 1084 if (v1) {
nixnax 142:54d1543e23e5 1085 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 1086 checkPc();
nixnax 154:18b2bd92f557 1087 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTcp, dataLen); // 1 for more verbose
nixnax 142:54d1543e23e5 1088 checkPc();
nixnax 142:54d1543e23e5 1089 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 1090 }
nixnax 142:54d1543e23e5 1091 if (dataLen > 0) {
nixnax 154:18b2bd92f557 1092 ppp.pkt.buf[4+ipHeaderLen+headerSizeTcp+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 154:18b2bd92f557 1093 putsWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTcp ); // print the tcp payload data
nixnax 142:54d1543e23e5 1094 putsWhileCheckingInput("\n");
nixnax 142:54d1543e23e5 1095 }
nixnax 142:54d1543e23e5 1096 }
nixnax 142:54d1543e23e5 1097
nixnax 142:54d1543e23e5 1098 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 1099 void TCPpacket()
nixnax 142:54d1543e23e5 1100 {
nixnax 142:54d1543e23e5 1101 dumpHeaderIP(0); // dump incoming packet header
nixnax 142:54d1543e23e5 1102 dumpHeaderTCP(0); // dump incoming packet header
nixnax 142:54d1543e23e5 1103 if (v2) dumpDataTCP();
nixnax 142:54d1543e23e5 1104 tcpHandler();
nixnax 142:54d1543e23e5 1105 }
nixnax 142:54d1543e23e5 1106
nixnax 142:54d1543e23e5 1107 /// handle the remaining IP protocols by ignoring them
nixnax 142:54d1543e23e5 1108 void otherProtocol()
nixnax 142:54d1543e23e5 1109 {
nixnax 142:54d1543e23e5 1110 debugPrintf("Other IP protocol");
nixnax 142:54d1543e23e5 1111 }
nixnax 142:54d1543e23e5 1112
nixnax 142:54d1543e23e5 1113 /// process an incoming IP packet
nixnax 142:54d1543e23e5 1114 void IPframe()
nixnax 142:54d1543e23e5 1115 {
nixnax 167:ff8a2d8beeb1 1116 int protocol = ppp.ip->protocol;
nixnax 142:54d1543e23e5 1117 switch (protocol) {
nixnax 142:54d1543e23e5 1118 case 1:
nixnax 142:54d1543e23e5 1119 ICMPpacket();
nixnax 142:54d1543e23e5 1120 break;
nixnax 142:54d1543e23e5 1121 case 2:
nixnax 142:54d1543e23e5 1122 IGMPpacket();
nixnax 142:54d1543e23e5 1123 break;
nixnax 142:54d1543e23e5 1124 case 17:
nixnax 142:54d1543e23e5 1125 UDPpacket();
nixnax 142:54d1543e23e5 1126 break;
nixnax 142:54d1543e23e5 1127 case 6:
nixnax 142:54d1543e23e5 1128 TCPpacket();
nixnax 142:54d1543e23e5 1129 break;
nixnax 142:54d1543e23e5 1130 default:
nixnax 142:54d1543e23e5 1131 otherProtocol();
nixnax 142:54d1543e23e5 1132 }
nixnax 142:54d1543e23e5 1133 }
nixnax 142:54d1543e23e5 1134
nixnax 142:54d1543e23e5 1135 /// respond to LCP (line configuration protocol) configuration request) by allowing no options
nixnax 142:54d1543e23e5 1136 void LCPconfReq()
nixnax 142:54d1543e23e5 1137 {
nixnax 142:54d1543e23e5 1138 debugPrintf("LCP Config ");
nixnax 142:54d1543e23e5 1139 if (ppp.pkt.buf[7] != 4) {
nixnax 142:54d1543e23e5 1140 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 142:54d1543e23e5 1141 debugPrintf("Reject\n");
nixnax 144:01d98cf7738e 1142 sendPppFrame();
nixnax 142:54d1543e23e5 1143 } else {
nixnax 142:54d1543e23e5 1144 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 142:54d1543e23e5 1145 debugPrintf("Ack\n");
nixnax 144:01d98cf7738e 1146 sendPppFrame();
nixnax 142:54d1543e23e5 1147 debugPrintf("LCP Ask\n");
nixnax 142:54d1543e23e5 1148 ppp.pkt.buf[4]=1; // request no options
nixnax 144:01d98cf7738e 1149 sendPppFrame();
nixnax 142:54d1543e23e5 1150 }
nixnax 142:54d1543e23e5 1151 }
nixnax 142:54d1543e23e5 1152
nixnax 142:54d1543e23e5 1153 /// handle LCP acknowledge packets by ignoring them
nixnax 142:54d1543e23e5 1154 void LCPconfAck()
nixnax 142:54d1543e23e5 1155 {
nixnax 142:54d1543e23e5 1156 debugPrintf("LCP Ack\n");
nixnax 142:54d1543e23e5 1157 }
nixnax 142:54d1543e23e5 1158
nixnax 143:c5019f856a56 1159 /// handle LCP end (disconnect) packets by acknowledging them and by setting ppp.online to false
nixnax 142:54d1543e23e5 1160 void LCPend()
nixnax 142:54d1543e23e5 1161 {
nixnax 142:54d1543e23e5 1162 ppp.pkt.buf[4]=6;
nixnax 144:01d98cf7738e 1163 sendPppFrame(); // acknowledge
nixnax 142:54d1543e23e5 1164 ppp.online=0; // start hunting for connect string again
nixnax 142:54d1543e23e5 1165 pppInitStruct(); // flush the receive buffer
nixnax 143:c5019f856a56 1166 debugPrintf("LCP End (Disconnect from host)\n");
nixnax 142:54d1543e23e5 1167 }
nixnax 142:54d1543e23e5 1168
nixnax 142:54d1543e23e5 1169 /// respond to other LCP requests by ignoring them
nixnax 142:54d1543e23e5 1170 void LCPother()
nixnax 142:54d1543e23e5 1171 {
nixnax 142:54d1543e23e5 1172 debugPrintf("LCP Other\n");
nixnax 142:54d1543e23e5 1173 dumpPPPFrame();
nixnax 142:54d1543e23e5 1174 }
nixnax 142:54d1543e23e5 1175
nixnax 142:54d1543e23e5 1176 /// process incoming LCP packets
nixnax 142:54d1543e23e5 1177 void LCPframe()
nixnax 142:54d1543e23e5 1178 {
nixnax 142:54d1543e23e5 1179 int code = ppp.pkt.buf[4];
nixnax 142:54d1543e23e5 1180 switch (code) {
nixnax 142:54d1543e23e5 1181 case 1:
nixnax 142:54d1543e23e5 1182 LCPconfReq();
nixnax 142:54d1543e23e5 1183 break; // config request
nixnax 142:54d1543e23e5 1184 case 2:
nixnax 142:54d1543e23e5 1185 LCPconfAck();
nixnax 142:54d1543e23e5 1186 break; // config ack
nixnax 142:54d1543e23e5 1187 case 5:
nixnax 142:54d1543e23e5 1188 LCPend();
nixnax 142:54d1543e23e5 1189 break; // end connection
nixnax 142:54d1543e23e5 1190 default:
nixnax 142:54d1543e23e5 1191 LCPother();
nixnax 142:54d1543e23e5 1192 }
nixnax 142:54d1543e23e5 1193 }
nixnax 142:54d1543e23e5 1194
nixnax 142:54d1543e23e5 1195 /// discard packets that are not IP, IPCP, or LCP
nixnax 142:54d1543e23e5 1196 void discardedFrame()
nixnax 142:54d1543e23e5 1197 {
nixnax 142:54d1543e23e5 1198 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 1199 }
nixnax 142:54d1543e23e5 1200
nixnax 142:54d1543e23e5 1201 /// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax 142:54d1543e23e5 1202 void determinePacketType()
nixnax 142:54d1543e23e5 1203 {
nixnax 167:ff8a2d8beeb1 1204 if ( ppp.ppp->address != 0xff ) {
nixnax 167:ff8a2d8beeb1 1205 debugPrintf("Unexpected: PPP address != ff\n");
nixnax 142:54d1543e23e5 1206 return;
nixnax 142:54d1543e23e5 1207 }
nixnax 167:ff8a2d8beeb1 1208 if ( ppp.ppp->control != 3 ) {
nixnax 167:ff8a2d8beeb1 1209 debugPrintf("Unexpected: PPP control != 3\n");
nixnax 142:54d1543e23e5 1210 return;
nixnax 142:54d1543e23e5 1211 }
nixnax 167:ff8a2d8beeb1 1212 unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax 167:ff8a2d8beeb1 1213 switch ( protocol ) {
nixnax 167:ff8a2d8beeb1 1214 case 0xc021:
nixnax 142:54d1543e23e5 1215 LCPframe();
nixnax 142:54d1543e23e5 1216 break; // link control
nixnax 167:ff8a2d8beeb1 1217 case 0x8021:
nixnax 142:54d1543e23e5 1218 IPCPframe();
nixnax 142:54d1543e23e5 1219 break; // IP control
nixnax 167:ff8a2d8beeb1 1220 case 0x0021:
nixnax 142:54d1543e23e5 1221 IPframe();
nixnax 142:54d1543e23e5 1222 break; // IP itself
nixnax 142:54d1543e23e5 1223 default:
nixnax 142:54d1543e23e5 1224 discardedFrame();
nixnax 142:54d1543e23e5 1225 }
nixnax 142:54d1543e23e5 1226 }
nixnax 142:54d1543e23e5 1227
nixnax 146:a45f49a2b29c 1228 /// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 146:a45f49a2b29c 1229 void sniff()
nixnax 146:a45f49a2b29c 1230 {
nixnax 146:a45f49a2b29c 1231 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 1232 }
nixnax 146:a45f49a2b29c 1233
nixnax 142:54d1543e23e5 1234 /// scan the PPP serial input stream for frame start markers
nixnax 143:c5019f856a56 1235 void waitForPppFrame()
nixnax 142:54d1543e23e5 1236 {
nixnax 142:54d1543e23e5 1237 while(1) {
nixnax 142:54d1543e23e5 1238 checkPc(); // handle received characters
nixnax 142:54d1543e23e5 1239 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 142:54d1543e23e5 1240 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 142:54d1543e23e5 1241 int rx = pc_getBuf(); // get the character
nixnax 142:54d1543e23e5 1242 if (rx==FRAME_7E) {
nixnax 142:54d1543e23e5 1243 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 142:54d1543e23e5 1244 ppp.firstFrame=0;
nixnax 142:54d1543e23e5 1245 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1246 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 142:54d1543e23e5 1247 } else {
nixnax 142:54d1543e23e5 1248 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 142:54d1543e23e5 1249 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 142:54d1543e23e5 1250 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1251 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax 142:54d1543e23e5 1252 break;
nixnax 142:54d1543e23e5 1253 }
nixnax 142:54d1543e23e5 1254 }
nixnax 142:54d1543e23e5 1255 }
nixnax 142:54d1543e23e5 1256 }
nixnax 142:54d1543e23e5 1257 }
nixnax 142:54d1543e23e5 1258
nixnax 153:7993def8663f 1259 /// 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 1260 // Note: a 0x7E in the input stream (ppp start of frame character) will also set ppp.online to true - see checkPc();
nixnax 153:7993def8663f 1261 void waitForPcConnectString()
nixnax 142:54d1543e23e5 1262 {
nixnax 142:54d1543e23e5 1263 while(ppp.online == 0) {
nixnax 142:54d1543e23e5 1264 checkPc(); // gather received characters
nixnax 142:54d1543e23e5 1265 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 142:54d1543e23e5 1266 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 142:54d1543e23e5 1267 if (found1 != NULL) {
nixnax 142:54d1543e23e5 1268 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 143:c5019f856a56 1269 if (v0) debugPrintf("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 142:54d1543e23e5 1270 pc.puts("CLIENTSERVER");
nixnax 142:54d1543e23e5 1271 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 142:54d1543e23e5 1272 checkPc();
nixnax 142:54d1543e23e5 1273 }
nixnax 142:54d1543e23e5 1274 }
nixnax 142:54d1543e23e5 1275 }
nixnax 142:54d1543e23e5 1276
nixnax 144:01d98cf7738e 1277 /// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax 144:01d98cf7738e 1278 void initializePpp()
nixnax 142:54d1543e23e5 1279 {
nixnax 142:54d1543e23e5 1280 pc.baud(115200); // USB serial port to pc
nixnax 144:01d98cf7738e 1281 debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax 142:54d1543e23e5 1282 debugPrintf("\x1b[2J\x1b[H\x1b[30mmbed PPP-Blinky HTTP & WebSocket server ready :)\n"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
nixnax 142:54d1543e23e5 1283 pppInitStruct(); // initialize all the PPP properties
nixnax 143:c5019f856a56 1284 }