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@150:3366bf3d294e, 2017-08-30 (annotated)

Committer:
nixnax
Date:
Wed Aug 30 16:34:51 2017 +0000
Revision:
150:3366bf3d294e
Parent:
149:969d98f6fb88
Child:
152:025c73b6c0a9
changed connected() to connectedPPP()

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 148:4225c3608b80 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 150:3366bf3d294e 108 // this is websocket demo 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 142:54d1543e23e5 158 /// a structure to keep all our ppp globals in
nixnax 142:54d1543e23e5 159 struct pppType {
nixnax 142:54d1543e23e5 160 int online; // we hunt for a PPP connection if this is zero
nixnax 143:c5019f856a56 161 int hostIP; // ip address of host
nixnax 145:098b6ed2f7f2 162 int fcs; // PPP "frame check sequence" - a 16-bit HDLC-like checksum used in all PPP frames
nixnax 142:54d1543e23e5 163 int ledState; // state of LED1
nixnax 146:a45f49a2b29c 164 int responseCounter;
nixnax 142:54d1543e23e5 165 int firstFrame; // cleared after first frame
nixnax 142:54d1543e23e5 166 struct {
nixnax 142:54d1543e23e5 167 #define RXBUFLEN (1<<11)
nixnax 142:54d1543e23e5 168 // the serial port receive buffer and packet buffer, size is RXBUFLEN (currently 2048 bytes)
nixnax 142:54d1543e23e5 169 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in ring buffer
nixnax 142:54d1543e23e5 170 int head;
nixnax 142:54d1543e23e5 171 int tail;
nixnax 142:54d1543e23e5 172 int rtail;
nixnax 142:54d1543e23e5 173 int buflevel;
nixnax 142:54d1543e23e5 174 } rx; // serial port objects
nixnax 142:54d1543e23e5 175 struct {
nixnax 142:54d1543e23e5 176 int len; // number of bytes in buffer
nixnax 142:54d1543e23e5 177 int crc; // PPP CRC (frame check)
nixnax 142:54d1543e23e5 178 #define PPP_max_size 2500
nixnax 142:54d1543e23e5 179 // we are assuming 1000 bytes more than MTU size of 1500 - due to the PPP encoding of special bytes
nixnax 142:54d1543e23e5 180 char buf[PPP_max_size]; // send and receive buffer large enough for raw, encoded PPP/HDLC frames
nixnax 142:54d1543e23e5 181 } pkt; // ppp buffer objects
nixnax 142:54d1543e23e5 182 struct {
nixnax 142:54d1543e23e5 183 int frameStartIndex; // frame start marker
nixnax 142:54d1543e23e5 184 int frameEndIndex; // frame end marker
nixnax 142:54d1543e23e5 185 } hdlc; // hdlc frame objects
nixnax 142:54d1543e23e5 186 struct {
nixnax 142:54d1543e23e5 187 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 142:54d1543e23e5 188 } ip; // ip related object
nixnax 142:54d1543e23e5 189 };
nixnax 142:54d1543e23e5 190
nixnax 142:54d1543e23e5 191 pppType ppp; // our global - definitely not thread safe
nixnax 142:54d1543e23e5 192
nixnax 142:54d1543e23e5 193 /// Initialize the ppp structure and clear the receive buffer
nixnax 142:54d1543e23e5 194 void pppInitStruct()
nixnax 142:54d1543e23e5 195 {
nixnax 142:54d1543e23e5 196 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 142:54d1543e23e5 197 ppp.online=0;
nixnax 142:54d1543e23e5 198 ppp.rx.tail=0;
nixnax 142:54d1543e23e5 199 ppp.rx.rtail=0;
nixnax 142:54d1543e23e5 200 ppp.rx.head=0;
nixnax 142:54d1543e23e5 201 ppp.rx.buflevel=0;
nixnax 142:54d1543e23e5 202 ppp.pkt.len=0;
nixnax 142:54d1543e23e5 203 ppp.ip.ident=10000; // easy to recognize in ip packet dumps
nixnax 142:54d1543e23e5 204 ppp.ledState=0;
nixnax 142:54d1543e23e5 205 ppp.hdlc.frameStartIndex=0;
nixnax 146:a45f49a2b29c 206 ppp.responseCounter=0;
nixnax 142:54d1543e23e5 207 ppp.firstFrame=1;
nixnax 142:54d1543e23e5 208 }
nixnax 142:54d1543e23e5 209
nixnax 142:54d1543e23e5 210 /// Toggle the LED on every second PPP packet received
nixnax 142:54d1543e23e5 211 void led1Toggle()
nixnax 142:54d1543e23e5 212 {
nixnax 142:54d1543e23e5 213 led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax 143:c5019f856a56 214 ppp.ledState++;
nixnax 142:54d1543e23e5 215 }
nixnax 142:54d1543e23e5 216
nixnax 142:54d1543e23e5 217 /// returns 1 after a connect messasge, 0 at startup or after a disconnect message
nixnax 150:3366bf3d294e 218 int connectedPpp()
nixnax 142:54d1543e23e5 219 {
nixnax 142:54d1543e23e5 220 return ppp.online;
nixnax 143:c5019f856a56 221 }
nixnax 142:54d1543e23e5 222
nixnax 143:c5019f856a56 223 /// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax 143:c5019f856a56 224 /// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax 142:54d1543e23e5 225 void checkPc()
nixnax 142:54d1543e23e5 226 {
nixnax 142:54d1543e23e5 227 char ch;
nixnax 142:54d1543e23e5 228 if ( pc.readable() ) {
nixnax 142:54d1543e23e5 229 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 142:54d1543e23e5 230 if ( hd == ppp.rx.rtail ) {
nixnax 142:54d1543e23e5 231 debugPrintf("\nReceive buffer full\n");
nixnax 142:54d1543e23e5 232 return;
nixnax 142:54d1543e23e5 233 }
nixnax 142:54d1543e23e5 234 ch = pc.getc(); // read new character
nixnax 142:54d1543e23e5 235 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 142:54d1543e23e5 236 if ( ppp.online == 0 ) {
nixnax 142:54d1543e23e5 237 if (ch == 0x7E) {
nixnax 142:54d1543e23e5 238 ppp.online = 1;
nixnax 142:54d1543e23e5 239 }
nixnax 142:54d1543e23e5 240 }
nixnax 142:54d1543e23e5 241 ppp.rx.head = hd; // update head pointer
nixnax 142:54d1543e23e5 242 ppp.rx.buflevel++;
nixnax 142:54d1543e23e5 243 }
nixnax 142:54d1543e23e5 244 }
nixnax 142:54d1543e23e5 245
nixnax 142:54d1543e23e5 246 /// print to debug port while checking for incoming characters
nixnax 142:54d1543e23e5 247 void putcWhileCheckingInput( char outByte )
nixnax 142:54d1543e23e5 248 {
nixnax 142:54d1543e23e5 249 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 250 checkPc();
nixnax 142:54d1543e23e5 251 debugPutc( outByte );
nixnax 142:54d1543e23e5 252 checkPc();
nixnax 142:54d1543e23e5 253 #endif
nixnax 142:54d1543e23e5 254 }
nixnax 142:54d1543e23e5 255
nixnax 142:54d1543e23e5 256 /// puts to debug port while checking the PPP input stream
nixnax 142:54d1543e23e5 257 void putsWhileCheckingInput( char * data )
nixnax 142:54d1543e23e5 258 {
nixnax 142:54d1543e23e5 259 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 260 char * nextChar = data;
nixnax 142:54d1543e23e5 261 while( *nextChar != 0 ) {
nixnax 142:54d1543e23e5 262 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 142:54d1543e23e5 263 nextChar++;
nixnax 142:54d1543e23e5 264 }
nixnax 142:54d1543e23e5 265 #endif
nixnax 142:54d1543e23e5 266 }
nixnax 142:54d1543e23e5 267
nixnax 145:098b6ed2f7f2 268 /// Initialize the PPP FCS (frame check sequence) total
nixnax 145:098b6ed2f7f2 269 void fcsReset()
nixnax 142:54d1543e23e5 270 {
nixnax 145:098b6ed2f7f2 271 ppp.fcs=0xffff; // crc restart
nixnax 142:54d1543e23e5 272 }
nixnax 142:54d1543e23e5 273
nixnax 145:098b6ed2f7f2 274 /// update the cumulative PPP FCS (frame check sequence)
nixnax 145:098b6ed2f7f2 275 void fcsDo(int x)
nixnax 142:54d1543e23e5 276 {
nixnax 142:54d1543e23e5 277 for (int i=0; i<8; i++) {
nixnax 145:098b6ed2f7f2 278 ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1; // crc calculator
nixnax 142:54d1543e23e5 279 x>>=1;
nixnax 142:54d1543e23e5 280 }
nixnax 142:54d1543e23e5 281 checkPc(); // handle input
nixnax 142:54d1543e23e5 282 }
nixnax 142:54d1543e23e5 283
nixnax 145:098b6ed2f7f2 284 /// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax 145:098b6ed2f7f2 285 int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax 142:54d1543e23e5 286 {
nixnax 145:098b6ed2f7f2 287 fcsReset();
nixnax 145:098b6ed2f7f2 288 for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax 145:098b6ed2f7f2 289 return ppp.fcs;
nixnax 142:54d1543e23e5 290 }
nixnax 142:54d1543e23e5 291
nixnax 142:54d1543e23e5 292 /// Get one character from our received PPP buffer
nixnax 142:54d1543e23e5 293 int pc_getBuf()
nixnax 142:54d1543e23e5 294 {
nixnax 142:54d1543e23e5 295 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 142:54d1543e23e5 296 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 142:54d1543e23e5 297 ppp.rx.buflevel--;
nixnax 142:54d1543e23e5 298 return x;
nixnax 142:54d1543e23e5 299 }
nixnax 142:54d1543e23e5 300
nixnax 142:54d1543e23e5 301 /// Dump a PPP frame to the debug serial port
nixnax 142:54d1543e23e5 302 /// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 142:54d1543e23e5 303 /// Capture the frame's hex output in your terminal program and save as a text file
nixnax 142:54d1543e23e5 304 /// In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 142:54d1543e23e5 305 void dumpPPPFrame()
nixnax 142:54d1543e23e5 306 {
nixnax 142:54d1543e23e5 307 char pbuf[30];
nixnax 142:54d1543e23e5 308 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 309 checkPc();
nixnax 142:54d1543e23e5 310 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 142:54d1543e23e5 311 checkPc();
nixnax 142:54d1543e23e5 312 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 313 }
nixnax 142:54d1543e23e5 314 checkPc();
nixnax 142:54d1543e23e5 315 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 142:54d1543e23e5 316 checkPc();
nixnax 142:54d1543e23e5 317 putsWhileCheckingInput(pbuf);
nixnax 142:54d1543e23e5 318 }
nixnax 142:54d1543e23e5 319
nixnax 142:54d1543e23e5 320 /// Process a received PPP frame
nixnax 142:54d1543e23e5 321 void processPPPFrame(int start, int end)
nixnax 142:54d1543e23e5 322 {
nixnax 142:54d1543e23e5 323 led1Toggle(); // change led1 state on every frame we receive
nixnax 142:54d1543e23e5 324 if(start==end) {
nixnax 142:54d1543e23e5 325 return; // empty frame
nixnax 142:54d1543e23e5 326 }
nixnax 145:098b6ed2f7f2 327 fcsReset();
nixnax 142:54d1543e23e5 328 char * dest = ppp.pkt.buf;
nixnax 142:54d1543e23e5 329 ppp.pkt.len=0;
nixnax 142:54d1543e23e5 330 int unstuff=0;
nixnax 142:54d1543e23e5 331 int idx = start;
nixnax 142:54d1543e23e5 332 while(1) {
nixnax 142:54d1543e23e5 333 checkPc();
nixnax 142:54d1543e23e5 334 if (unstuff==0) {
nixnax 142:54d1543e23e5 335 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 142:54d1543e23e5 336 else {
nixnax 142:54d1543e23e5 337 *dest = ppp.rx.buf[idx];
nixnax 142:54d1543e23e5 338 ppp.pkt.len++;
nixnax 142:54d1543e23e5 339 dest++;
nixnax 145:098b6ed2f7f2 340 fcsDo(ppp.rx.buf[idx]);
nixnax 142:54d1543e23e5 341 }
nixnax 142:54d1543e23e5 342 } else { // unstuff characters prefixed with 0x7d
nixnax 142:54d1543e23e5 343 *dest = ppp.rx.buf[idx]^0x20;
nixnax 142:54d1543e23e5 344 ppp.pkt.len++;
nixnax 142:54d1543e23e5 345 dest++;
nixnax 145:098b6ed2f7f2 346 fcsDo(ppp.rx.buf[idx]^0x20);
nixnax 142:54d1543e23e5 347 unstuff=0;
nixnax 142:54d1543e23e5 348 }
nixnax 142:54d1543e23e5 349 idx = (idx+1) & (RXBUFLEN-1);
nixnax 142:54d1543e23e5 350 if (idx == end) break;
nixnax 142:54d1543e23e5 351 }
nixnax 145:098b6ed2f7f2 352 ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax 142:54d1543e23e5 353 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 142:54d1543e23e5 354 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 142:54d1543e23e5 355 determinePacketType();
nixnax 142:54d1543e23e5 356 } else {
nixnax 142:54d1543e23e5 357 #define REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 358 #ifdef REPORT_FCS_ERROR_YES
nixnax 142:54d1543e23e5 359 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 360 checkPc();
nixnax 142:54d1543e23e5 361 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 142:54d1543e23e5 362 checkPc();
nixnax 142:54d1543e23e5 363 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 364 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 142:54d1543e23e5 365 #endif
nixnax 142:54d1543e23e5 366 }
nixnax 142:54d1543e23e5 367 }
nixnax 142:54d1543e23e5 368
nixnax 142:54d1543e23e5 369 /// output a character to the PPP port while checking for incoming characters
nixnax 142:54d1543e23e5 370 void pcPutcWhileCheckingInput(int ch)
nixnax 142:54d1543e23e5 371 {
nixnax 142:54d1543e23e5 372 checkPc(); // check input
nixnax 142:54d1543e23e5 373 pc.putc(ch);
nixnax 142:54d1543e23e5 374 checkPc();
nixnax 142:54d1543e23e5 375 }
nixnax 142:54d1543e23e5 376
nixnax 142:54d1543e23e5 377 /// do PPP HDLC-like handling of special (flag) characters
nixnax 143:c5019f856a56 378 void hdlcPut(int ch)
nixnax 142:54d1543e23e5 379 {
nixnax 142:54d1543e23e5 380 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 142:54d1543e23e5 381 pcPutcWhileCheckingInput(0x7d);
nixnax 142:54d1543e23e5 382 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 142:54d1543e23e5 383 } else {
nixnax 142:54d1543e23e5 384 pcPutcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 385 }
nixnax 142:54d1543e23e5 386 }
nixnax 142:54d1543e23e5 387
nixnax 142:54d1543e23e5 388 /// send a PPP frame in HDLC format
nixnax 144:01d98cf7738e 389 void sendPppFrame()
nixnax 143:c5019f856a56 390 {
nixnax 145:098b6ed2f7f2 391 int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 142:54d1543e23e5 392 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 142:54d1543e23e5 393 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 142:54d1543e23e5 394 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 142:54d1543e23e5 395 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 142:54d1543e23e5 396 wait_us(86); // wait one character time
nixnax 142:54d1543e23e5 397 checkPc();
nixnax 142:54d1543e23e5 398 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 142:54d1543e23e5 399 }
nixnax 142:54d1543e23e5 400 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 142:54d1543e23e5 401 }
nixnax 142:54d1543e23e5 402
nixnax 143:c5019f856a56 403 /// 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 404 int bufferToIP(char * buffer)
nixnax 143:c5019f856a56 405 {
nixnax 143:c5019f856a56 406 int result=0;
nixnax 143:c5019f856a56 407 for(int i=0; i<4; i++) result = (result<<8)|(*buffer++ & 0xff);
nixnax 143:c5019f856a56 408 return result;
nixnax 143:c5019f856a56 409 }
nixnax 143:c5019f856a56 410
nixnax 142:54d1543e23e5 411 /// handle IPCP configuration requests
nixnax 142:54d1543e23e5 412 void ipcpConfigRequestHandler()
nixnax 142:54d1543e23e5 413 {
nixnax 142:54d1543e23e5 414 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 143:c5019f856a56 415 if(ppp.pkt.buf[8]==3) {
nixnax 143:c5019f856a56 416 ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax 143:c5019f856a56 417 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 418 }
nixnax 143:c5019f856a56 419
nixnax 142:54d1543e23e5 420 ppp.pkt.buf[4]=2; // change code to ack
nixnax 144:01d98cf7738e 421 sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 142:54d1543e23e5 422
nixnax 142:54d1543e23e5 423 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 142:54d1543e23e5 424 ppp.pkt.buf[4]=1; // change code to request
nixnax 142:54d1543e23e5 425 ppp.pkt.buf[7]=4; // no options in this request
nixnax 142:54d1543e23e5 426 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 144:01d98cf7738e 427 sendPppFrame(); // send our request
nixnax 142:54d1543e23e5 428 }
nixnax 142:54d1543e23e5 429
nixnax 142:54d1543e23e5 430 /// handle IPCP acknowledge (do nothing)
nixnax 142:54d1543e23e5 431 void ipcpAckHandler()
nixnax 142:54d1543e23e5 432 {
nixnax 142:54d1543e23e5 433 debugPrintf("Their IPCP Grant\n");
nixnax 142:54d1543e23e5 434 }
nixnax 142:54d1543e23e5 435
nixnax 143:c5019f856a56 436 /// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax 143:c5019f856a56 437 /// 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 438 void ipcpNackHandler()
nixnax 142:54d1543e23e5 439 {
nixnax 146:a45f49a2b29c 440 debugPrintf("Their IPCP Nack\n");
nixnax 142:54d1543e23e5 441 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 142:54d1543e23e5 442 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 144:01d98cf7738e 443 sendPppFrame(); // let's request this IP address as ours
nixnax 143:c5019f856a56 444 debugPrintf("Our IPCP ACK (received an IP)\n");
nixnax 146:a45f49a2b29c 445 } else { // if it's not an IP nack we ignore it
nixnax 146:a45f49a2b29c 446 debugPrintf("IPCP Nack Ignored\n");
nixnax 146:a45f49a2b29c 447 }
nixnax 142:54d1543e23e5 448 }
nixnax 142:54d1543e23e5 449
nixnax 142:54d1543e23e5 450 /// handle all other IPCP requests (by ignoring them)
nixnax 142:54d1543e23e5 451 void ipcpDefaultHandler()
nixnax 142:54d1543e23e5 452 {
nixnax 142:54d1543e23e5 453 debugPrintf("Their IPCP Other\n");
nixnax 142:54d1543e23e5 454 }
nixnax 142:54d1543e23e5 455
nixnax 142:54d1543e23e5 456 /// process an incoming IPCP packet
nixnax 142:54d1543e23e5 457 void IPCPframe()
nixnax 142:54d1543e23e5 458 {
nixnax 142:54d1543e23e5 459 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 142:54d1543e23e5 460 switch (code) {
nixnax 142:54d1543e23e5 461 case 1:
nixnax 142:54d1543e23e5 462 ipcpConfigRequestHandler();
nixnax 142:54d1543e23e5 463 break;
nixnax 142:54d1543e23e5 464 case 2:
nixnax 142:54d1543e23e5 465 ipcpAckHandler();
nixnax 142:54d1543e23e5 466 break;
nixnax 142:54d1543e23e5 467 case 3:
nixnax 142:54d1543e23e5 468 ipcpNackHandler();
nixnax 142:54d1543e23e5 469 break;
nixnax 142:54d1543e23e5 470 default:
nixnax 142:54d1543e23e5 471 ipcpDefaultHandler();
nixnax 142:54d1543e23e5 472 }
nixnax 142:54d1543e23e5 473 }
nixnax 142:54d1543e23e5 474
nixnax 142:54d1543e23e5 475 /// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax 142:54d1543e23e5 476 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 142:54d1543e23e5 477 {
nixnax 142:54d1543e23e5 478 unsigned int i,hi,lo,sum;
nixnax 142:54d1543e23e5 479 unsigned char placeHolder;
nixnax 142:54d1543e23e5 480 if (len&1) {
nixnax 142:54d1543e23e5 481 placeHolder = ptr[len];
nixnax 142:54d1543e23e5 482 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 483 }
nixnax 142:54d1543e23e5 484 sum=0;
nixnax 142:54d1543e23e5 485 i=0;
nixnax 142:54d1543e23e5 486 while ( i<len ) {
nixnax 142:54d1543e23e5 487 checkPc();
nixnax 142:54d1543e23e5 488 hi = ptr[i++];
nixnax 142:54d1543e23e5 489 lo = ptr[i++];
nixnax 142:54d1543e23e5 490 sum = sum + ( (hi<<8) | lo );
nixnax 142:54d1543e23e5 491 }
nixnax 142:54d1543e23e5 492 if (len&1) {
nixnax 142:54d1543e23e5 493 ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax 142:54d1543e23e5 494 }
nixnax 142:54d1543e23e5 495 sum = (sum & 0xffff) + (sum>>16);
nixnax 142:54d1543e23e5 496 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 142:54d1543e23e5 497 return ~sum;
nixnax 142:54d1543e23e5 498 }
nixnax 142:54d1543e23e5 499
nixnax 142:54d1543e23e5 500 /// perform the checksum on an IP header
nixnax 146:a45f49a2b29c 501 void IpHeaderCheckSum()
nixnax 142:54d1543e23e5 502 {
nixnax 146:a45f49a2b29c 503 ppp.pkt.buf[4+10]=0; // zero the checsum in the IP header
nixnax 146:a45f49a2b29c 504 ppp.pkt.buf[4+11]=0; // zero the checksum in the IP header
nixnax 146:a45f49a2b29c 505 int len =(ppp.pkt.buf[4]&0xf)*4; // length of IP header in bytes
nixnax 146:a45f49a2b29c 506 char * ptr = ppp.pkt.buf+4; // start of IP packet
nixnax 142:54d1543e23e5 507 int sum=0;
nixnax 142:54d1543e23e5 508 for (int i=0; i<len/2; i++) {
nixnax 142:54d1543e23e5 509 int hi = *ptr;
nixnax 142:54d1543e23e5 510 ptr++;
nixnax 142:54d1543e23e5 511 int lo = *ptr;
nixnax 142:54d1543e23e5 512 ptr++;
nixnax 142:54d1543e23e5 513 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 142:54d1543e23e5 514 sum = sum + val;
nixnax 142:54d1543e23e5 515 checkPc();
nixnax 142:54d1543e23e5 516 }
nixnax 142:54d1543e23e5 517 sum = sum + (sum>>16);
nixnax 142:54d1543e23e5 518 sum = ~sum;
nixnax 146:a45f49a2b29c 519 ppp.pkt.buf[4+10]= (sum>>8);
nixnax 146:a45f49a2b29c 520 ppp.pkt.buf[4+11]= (sum );
nixnax 146:a45f49a2b29c 521 }
nixnax 146:a45f49a2b29c 522
nixnax 147:0f40005cbc5f 523 /// swap the IP source and destination addresses
nixnax 147:0f40005cbc5f 524 void swapIpAddresses()
nixnax 147:0f40005cbc5f 525 {
nixnax 147:0f40005cbc5f 526 char tempHold[4];
nixnax 147:0f40005cbc5f 527 memcpy(tempHold, ppp.pkt.buf+16,4); // tempHold <- source IP
nixnax 147:0f40005cbc5f 528 memcpy(ppp.pkt.buf+16, ppp.pkt.buf+20,4); // source <- dest
nixnax 147:0f40005cbc5f 529 memcpy(ppp.pkt.buf+20, tempHold,4); // dest <- tempHold
nixnax 147:0f40005cbc5f 530 }
nixnax 147:0f40005cbc5f 531
nixnax 149:969d98f6fb88 532 /// swap the IP source and destination ports
nixnax 149:969d98f6fb88 533 void swapIpPorts()
nixnax 149:969d98f6fb88 534 {
nixnax 149:969d98f6fb88 535 int headerSizeIP = 4*(ppp.pkt.buf[4]&0xf); // calculate size of IP header
nixnax 149:969d98f6fb88 536 char * ipSrcPort = 4 + ppp.pkt.buf + headerSizeIP + 0; // ip source port location
nixnax 149:969d98f6fb88 537 char * ipDstPort = 4 + ppp.pkt.buf + headerSizeIP + 2; // ip destin port location
nixnax 149:969d98f6fb88 538 char tempHold[2];
nixnax 149:969d98f6fb88 539 memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax 149:969d98f6fb88 540 memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax 149:969d98f6fb88 541 memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax 149:969d98f6fb88 542 }
nixnax 149:969d98f6fb88 543
nixnax 146:a45f49a2b29c 544 /// Process an incoming UDP packet.
nixnax 146:a45f49a2b29c 545 /// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax 146:a45f49a2b29c 546 void UDPpacket()
nixnax 146:a45f49a2b29c 547 {
nixnax 146:a45f49a2b29c 548 char * ipHeader = ppp.pkt.buf+4; // udp packet start
nixnax 146:a45f49a2b29c 549 char * ipSizeBuf = ipHeader+2; // size of IP packet
nixnax 146:a45f49a2b29c 550 int headerSizeIP = 4*(ipHeader[0]&0xf); // size of IP header
nixnax 146:a45f49a2b29c 551 char * udpHeader = ipHeader + headerSizeIP; // udp info start
nixnax 146:a45f49a2b29c 552 char * udpLen = udpHeader+4; // udp data length
nixnax 146:a45f49a2b29c 553 char * udpCheckSum = udpHeader+6; // udp checksum
nixnax 146:a45f49a2b29c 554 char * udpData = udpHeader+8; // start of UDP data
nixnax 146:a45f49a2b29c 555 int udpLength = ((udpLen[0]<<8) | udpLen[1]); // size of udp packet
nixnax 146:a45f49a2b29c 556 int udpDataSize = udpLength - 8; // size of udp data
nixnax 147:0f40005cbc5f 557
nixnax 146:a45f49a2b29c 558 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 147:0f40005cbc5f 559 char * srcIP = ipHeader+12; // IP source
nixnax 147:0f40005cbc5f 560 char * dstIP = ipHeader+16; // IP destination
nixnax 149:969d98f6fb88 561 char * udpSrcPort = udpHeader+0; // source port
nixnax 149:969d98f6fb88 562 char * udpDstPort = udpHeader+2; // destination port
nixnax 146:a45f49a2b29c 563 int udpSrc = (udpSrcPort[0]<<8)|udpSrcPort[1]; // integer of UDP source port
nixnax 146:a45f49a2b29c 564 int udpDst = (udpDstPort[0]<<8)|udpDstPort[1]; // integer of UDP dest port
nixnax 146:a45f49a2b29c 565 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrc);
nixnax 146:a45f49a2b29c 566 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDst);
nixnax 146:a45f49a2b29c 567 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 146:a45f49a2b29c 568 if (v1) {
nixnax 146:a45f49a2b29c 569 int printSize = udpLength-8;
nixnax 146:a45f49a2b29c 570 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 146:a45f49a2b29c 571 for (int i=0; i<printSize; i++) {
nixnax 146:a45f49a2b29c 572 char ch = udpData[i];
nixnax 146:a45f49a2b29c 573 if (ch>31 && ch<127) {
nixnax 146:a45f49a2b29c 574 debugPrintf("%c", ch);
nixnax 146:a45f49a2b29c 575 } else {
nixnax 146:a45f49a2b29c 576 debugPrintf("_");
nixnax 146:a45f49a2b29c 577 }
nixnax 146:a45f49a2b29c 578 }
nixnax 146:a45f49a2b29c 579 }
nixnax 146:a45f49a2b29c 580 if (v0) debugPrintf("\n");
nixnax 146:a45f49a2b29c 581 #endif
nixnax 146:a45f49a2b29c 582 int echoFound = !strncmp(udpData,"echo ",5); // true if UDP message starts with "echo "
nixnax 146:a45f49a2b29c 583 int testFound = !strncmp(udpData,"test" ,4); // true if UDP message starts with "test"
nixnax 146:a45f49a2b29c 584 if ( (echoFound) || (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax 147:0f40005cbc5f 585 swapIpAddresses(); // swap IP source and destination
nixnax 149:969d98f6fb88 586 swapIpPorts(); // swap IP source and destination ports
nixnax 146:a45f49a2b29c 587 if (echoFound) {
nixnax 146:a45f49a2b29c 588 memcpy(udpData,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax 146:a45f49a2b29c 589 char endString[] = "} UDP Server: PPP-Blinky\n"; // an appendix
nixnax 146:a45f49a2b29c 590 memcpy(udpData+udpLength-8,endString,sizeof(endString)-1); // add endstring size to the UDP message
nixnax 146:a45f49a2b29c 591 udpDataSize = udpDataSize + sizeof(endString)-1; // update udp data size with the size of the appendix
nixnax 146:a45f49a2b29c 592 }
nixnax 146:a45f49a2b29c 593 if (testFound) {
nixnax 146:a45f49a2b29c 594 char udpResponse[50];
nixnax 146:a45f49a2b29c 595 int n = 0;
nixnax 146:a45f49a2b29c 596 n = n+sprintf(udpResponse+n,"Response count %d\n",ppp.responseCounter++);
nixnax 146:a45f49a2b29c 597 memcpy(udpData,udpResponse,n); // copy response to the UDP data area
nixnax 146:a45f49a2b29c 598 udpDataSize = n; // new udp data size
nixnax 146:a45f49a2b29c 599 }
nixnax 146:a45f49a2b29c 600 udpLength = udpDataSize+8; // update udp packet length
nixnax 146:a45f49a2b29c 601 int ipSize = headerSizeIP + udpLength; // update ip packet length
nixnax 146:a45f49a2b29c 602 ppp.pkt.len = ipSize+2+4; // update ppp packet length
nixnax 146:a45f49a2b29c 603 udpLen[0] = udpLength>>8;
nixnax 146:a45f49a2b29c 604 udpLen[1] = udpLength; // update UDP length
nixnax 146:a45f49a2b29c 605 ipSizeBuf[0] = ipSize>>8;
nixnax 146:a45f49a2b29c 606 ipSizeBuf[1] = ipSize; // update IP length
nixnax 146:a45f49a2b29c 607 IpHeaderCheckSum(); // update IP header checksum
nixnax 146:a45f49a2b29c 608 memset(udpCheckSum,0,2); // we don't yet recompute the checksum (it's optional), so have to zero it
nixnax 146:a45f49a2b29c 609 sendPppFrame(); // send the UDP message back
nixnax 146:a45f49a2b29c 610 }
nixnax 142:54d1543e23e5 611 }
nixnax 142:54d1543e23e5 612
nixnax 142:54d1543e23e5 613 /// handle a PING ICMP (internet control message protocol) packet
nixnax 142:54d1543e23e5 614 void ICMPpacket() // internet control message protocol
nixnax 142:54d1543e23e5 615 {
nixnax 142:54d1543e23e5 616 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 142:54d1543e23e5 617 char * pktLen = ipPkt+2;
nixnax 142:54d1543e23e5 618 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 142:54d1543e23e5 619 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 142:54d1543e23e5 620 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 142:54d1543e23e5 621 char * icmpSum = icmpType+2; // icmp checksum
nixnax 142:54d1543e23e5 622 #define ICMP_TYPE_PING_REQUEST 8
nixnax 142:54d1543e23e5 623 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 142:54d1543e23e5 624 char * ipTTL = ipPkt+8; // time to live
nixnax 147:0f40005cbc5f 625 ipTTL[0]--; // decrement time to live (so we have to update header checksum)
nixnax 147:0f40005cbc5f 626 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 142:54d1543e23e5 627 char * srcAdr = ipPkt+12;
nixnax 142:54d1543e23e5 628 char * dstAdr = ipPkt+16;
nixnax 142:54d1543e23e5 629 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 142:54d1543e23e5 630 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 142:54d1543e23e5 631 if(1) {
nixnax 142:54d1543e23e5 632 char pbuf[50];
nixnax 142:54d1543e23e5 633 checkPc();
nixnax 142:54d1543e23e5 634 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 635 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 636 checkPc();
nixnax 142:54d1543e23e5 637 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 142:54d1543e23e5 638 checkPc();
nixnax 142:54d1543e23e5 639 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 640 }
nixnax 142:54d1543e23e5 641 #endif
nixnax 147:0f40005cbc5f 642 swapIpAddresses(); // swap the IP source and destination addresses
nixnax 147:0f40005cbc5f 643 IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax 142:54d1543e23e5 644 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 142:54d1543e23e5 645 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 142:54d1543e23e5 646 icmpSum[0]=0;
nixnax 142:54d1543e23e5 647 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 142:54d1543e23e5 648 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 142:54d1543e23e5 649 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 142:54d1543e23e5 650 icmpSum[0]=(sum>>8)&0xff;
nixnax 142:54d1543e23e5 651 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 142:54d1543e23e5 652
nixnax 142:54d1543e23e5 653 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 142:54d1543e23e5 654 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 142:54d1543e23e5 655 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 142:54d1543e23e5 656 if (0) {
nixnax 142:54d1543e23e5 657 for (int i=0; i<printSize; i++) {
nixnax 142:54d1543e23e5 658 char ch = icmpData[i];
nixnax 142:54d1543e23e5 659 if (ch>31 && ch<127) {
nixnax 142:54d1543e23e5 660 putcWhileCheckingInput(ch);
nixnax 142:54d1543e23e5 661 } else {
nixnax 142:54d1543e23e5 662 putcWhileCheckingInput('_');
nixnax 142:54d1543e23e5 663 }
nixnax 142:54d1543e23e5 664 }
nixnax 142:54d1543e23e5 665 putcWhileCheckingInput('\n');
nixnax 142:54d1543e23e5 666 }
nixnax 144:01d98cf7738e 667 sendPppFrame(); // reply to the ping
nixnax 142:54d1543e23e5 668 } else {
nixnax 142:54d1543e23e5 669 if (v0) {
nixnax 142:54d1543e23e5 670 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 142:54d1543e23e5 671 }
nixnax 142:54d1543e23e5 672 }
nixnax 142:54d1543e23e5 673 }
nixnax 142:54d1543e23e5 674
nixnax 142:54d1543e23e5 675 /// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax 142:54d1543e23e5 676 void IGMPpacket()
nixnax 142:54d1543e23e5 677 {
nixnax 142:54d1543e23e5 678 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 142:54d1543e23e5 679 }
nixnax 142:54d1543e23e5 680
nixnax 142:54d1543e23e5 681 /// dump the header of an IP pakcet on the (optional) debug serial port
nixnax 142:54d1543e23e5 682 void dumpHeaderIP (int outGoing)
nixnax 142:54d1543e23e5 683 {
nixnax 142:54d1543e23e5 684 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 142:54d1543e23e5 685 checkPc(); // we are expecting the first character of the next packet
nixnax 142:54d1543e23e5 686 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 142:54d1543e23e5 687 char * ident = ipPkt+4; // 2 bytes
nixnax 142:54d1543e23e5 688 #ifdef UNUSED_IP_VARIABLES
nixnax 142:54d1543e23e5 689 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 142:54d1543e23e5 690 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 142:54d1543e23e5 691 char * version = ipPkt; // top 4 bits
nixnax 142:54d1543e23e5 692 char * ihl = ipPkt; // bottom 4 bits
nixnax 142:54d1543e23e5 693 char * dscp = ipPkt+1; // top 6 bits
nixnax 142:54d1543e23e5 694 char * ecn = ipPkt+1; // lower 2 bits
nixnax 142:54d1543e23e5 695 char * pktLen = ipPkt+2; // 2 bytes
nixnax 142:54d1543e23e5 696 char * flags = ipPkt+6; // 2 bits
nixnax 142:54d1543e23e5 697 char * ttl = ipPkt+8; // 1 byte
nixnax 142:54d1543e23e5 698 char * protocol = ipPkt+9; // 1 byte
nixnax 142:54d1543e23e5 699 char * headercheck= ipPkt+10; // 2 bytes
nixnax 142:54d1543e23e5 700 int versionIP = (version[0]>>4)&0xf;
nixnax 142:54d1543e23e5 701 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 142:54d1543e23e5 702 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 142:54d1543e23e5 703 int ecnIP = ecn[0]&3;
nixnax 142:54d1543e23e5 704 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 142:54d1543e23e5 705 int flagsIP = flags[0]>>14&3;
nixnax 142:54d1543e23e5 706 int ttlIP = ttl[0];
nixnax 142:54d1543e23e5 707 int protocolIP = protocol[0];
nixnax 142:54d1543e23e5 708 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 142:54d1543e23e5 709 #endif
nixnax 142:54d1543e23e5 710 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 142:54d1543e23e5 711 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 712 int n=0;
nixnax 142:54d1543e23e5 713 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 142:54d1543e23e5 714 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 715 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 142:54d1543e23e5 716 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 142:54d1543e23e5 717 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 142:54d1543e23e5 718 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 142:54d1543e23e5 719 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 720 #endif
nixnax 142:54d1543e23e5 721 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 722 #ifndef TCP_HEADER_DUMP_YES
nixnax 142:54d1543e23e5 723 putsWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 142:54d1543e23e5 724 #endif
nixnax 142:54d1543e23e5 725 #endif
nixnax 142:54d1543e23e5 726 }
nixnax 142:54d1543e23e5 727
nixnax 142:54d1543e23e5 728 /// dump a TCP header on the optional debug serial port
nixnax 142:54d1543e23e5 729 void dumpHeaderTCP(int outGoing)
nixnax 142:54d1543e23e5 730 {
nixnax 142:54d1543e23e5 731 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 142:54d1543e23e5 732 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 142:54d1543e23e5 733 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 142:54d1543e23e5 734 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 142:54d1543e23e5 735 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 142:54d1543e23e5 736 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 142:54d1543e23e5 737 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 142:54d1543e23e5 738 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 142:54d1543e23e5 739 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 142:54d1543e23e5 740 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 142:54d1543e23e5 741 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 142:54d1543e23e5 742 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 142:54d1543e23e5 743 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 142:54d1543e23e5 744 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 142:54d1543e23e5 745 flagInfo[8]=0; // null terminate string
nixnax 142:54d1543e23e5 746 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 142:54d1543e23e5 747 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 142:54d1543e23e5 748 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 142:54d1543e23e5 749 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 142:54d1543e23e5 750 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 142:54d1543e23e5 751 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 142:54d1543e23e5 752 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 142:54d1543e23e5 753 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 142:54d1543e23e5 754 #else
nixnax 142:54d1543e23e5 755 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 142:54d1543e23e5 756 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 142:54d1543e23e5 757 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 142:54d1543e23e5 758 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 142:54d1543e23e5 759 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 142:54d1543e23e5 760 flagInfo[1]=0; // ' '
nixnax 142:54d1543e23e5 761 flagInfo[2]=0;
nixnax 142:54d1543e23e5 762 #endif
nixnax 142:54d1543e23e5 763 putsWhileCheckingInput( flagInfo );
nixnax 142:54d1543e23e5 764 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 765 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 142:54d1543e23e5 766 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 142:54d1543e23e5 767 #endif
nixnax 142:54d1543e23e5 768 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 142:54d1543e23e5 769 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 142:54d1543e23e5 770 }
nixnax 142:54d1543e23e5 771 #endif
nixnax 142:54d1543e23e5 772 }
nixnax 142:54d1543e23e5 773
nixnax 143:c5019f856a56 774 /// Encode a buffer in base-64
nixnax 142:54d1543e23e5 775 void enc64(char * in, char * out, int len)
nixnax 142:54d1543e23e5 776 {
nixnax 142:54d1543e23e5 777 const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax 142:54d1543e23e5 778 int i,j,a,b,c;
nixnax 142:54d1543e23e5 779 i=0;
nixnax 142:54d1543e23e5 780 j=0;
nixnax 142:54d1543e23e5 781 while(1) {
nixnax 142:54d1543e23e5 782 if (i<len) {
nixnax 142:54d1543e23e5 783 a = in[i++];
nixnax 142:54d1543e23e5 784 out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax 142:54d1543e23e5 785 } else break;
nixnax 142:54d1543e23e5 786 if (i<len) {
nixnax 142:54d1543e23e5 787 b = in[i++];
nixnax 142:54d1543e23e5 788 out[j++] = lut[ ( (a << 4) & 0x30) | ( (b >> 4) & 0x0f) ];
nixnax 142:54d1543e23e5 789 out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax 142:54d1543e23e5 790 } else out[j++] = '=';
nixnax 142:54d1543e23e5 791 if (i<len) {
nixnax 142:54d1543e23e5 792 c = in[i++];
nixnax 142:54d1543e23e5 793 j--;
nixnax 142:54d1543e23e5 794 out[j++] = lut[ ( (b << 2) & 0x3c) | ( (c >> 6) & 0x03) ];
nixnax 142:54d1543e23e5 795 out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax 142:54d1543e23e5 796 } else out[j++] = '=';
nixnax 142:54d1543e23e5 797 }
nixnax 142:54d1543e23e5 798 out[j]=0;
nixnax 142:54d1543e23e5 799 }
nixnax 142:54d1543e23e5 800
nixnax 142:54d1543e23e5 801 /// handle a request for an http websocket
nixnax 142:54d1543e23e5 802 /// 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 803 int webSocketHandler(char * dataStart)
nixnax 142:54d1543e23e5 804 {
nixnax 142:54d1543e23e5 805 int n=0; // byte counter
nixnax 142:54d1543e23e5 806 char * key = strstr(dataStart, "Sec-WebSocket-Key: "); // search for the key in the payload
nixnax 142:54d1543e23e5 807 if (key != NULL) {
nixnax 142:54d1543e23e5 808 if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax 142:54d1543e23e5 809 char challenge [70];
nixnax 142:54d1543e23e5 810 strncpy(challenge,key+19,70); // a local buffer
nixnax 142:54d1543e23e5 811 *strchr(challenge,'\r')=0; // insert null so we can use sprintf
nixnax 142:54d1543e23e5 812 strncat(challenge,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11",70); // append websocket gui code
nixnax 142:54d1543e23e5 813 char shaOutput [20]; // sha1 output
nixnax 142:54d1543e23e5 814 sha1( shaOutput, challenge, strlen(challenge));
nixnax 142:54d1543e23e5 815 char encOut[50];
nixnax 142:54d1543e23e5 816 enc64( shaOutput, encOut, 20);
nixnax 142:54d1543e23e5 817 char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax 142:54d1543e23e5 818 char * version = challenge;
nixnax 142:54d1543e23e5 819 strncpy(version, versionstring,70); // copy version string
nixnax 142:54d1543e23e5 820 *strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax 142:54d1543e23e5 821 memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax 142:54d1543e23e5 822 n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax 142:54d1543e23e5 823 n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax 142:54d1543e23e5 824 n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax 142:54d1543e23e5 825 n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax 142:54d1543e23e5 826 n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax 142:54d1543e23e5 827 n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax 142:54d1543e23e5 828 n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax 142:54d1543e23e5 829 }
nixnax 142:54d1543e23e5 830 return n; // this response should satisfy a web browser's websocket protocol request
nixnax 142:54d1543e23e5 831 }
nixnax 142:54d1543e23e5 832
nixnax 142:54d1543e23e5 833 #define TCP_FLAG_ACK (1<<4)
nixnax 142:54d1543e23e5 834 #define TCP_FLAG_SYN (1<<1)
nixnax 142:54d1543e23e5 835 #define TCP_FLAG_PSH (1<<3)
nixnax 142:54d1543e23e5 836 #define TCP_FLAG_RST (1<<2)
nixnax 142:54d1543e23e5 837 #define TCP_FLAG_FIN (1<<0)
nixnax 142:54d1543e23e5 838
nixnax 142:54d1543e23e5 839 /// respond to an HTTP request
nixnax 142:54d1543e23e5 840 int httpResponse(char * dataStart)
nixnax 142:54d1543e23e5 841 {
nixnax 142:54d1543e23e5 842 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 843 n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax 142:54d1543e23e5 844 if (n>0) return n; // if it's a WebSocket we already have the response, so return
nixnax 142:54d1543e23e5 845
nixnax 142:54d1543e23e5 846 int nHeader; // byte size of HTTP header
nixnax 142:54d1543e23e5 847 int contentLengthStart; // index where HTML starts
nixnax 142:54d1543e23e5 848 int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax 142:54d1543e23e5 849
nixnax 146:a45f49a2b29c 850 ppp.responseCounter++; // increment the number of frames we have made
nixnax 142:54d1543e23e5 851
nixnax 142:54d1543e23e5 852 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax 142:54d1543e23e5 853 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 854 httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 855 httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax 142:54d1543e23e5 856 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 142:54d1543e23e5 857 if( (httpGetRoot==0) || (httpGetx==0) ) {
nixnax 142:54d1543e23e5 858 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax 142:54d1543e23e5 859 } else {
nixnax 142:54d1543e23e5 860 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 142:54d1543e23e5 861 }
nixnax 142:54d1543e23e5 862 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 142:54d1543e23e5 863 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 142:54d1543e23e5 864 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 142:54d1543e23e5 865 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 142:54d1543e23e5 866 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 867 nHeader=n; // size of HTTP header
nixnax 142:54d1543e23e5 868 if( httpGetRoot == 0 ) {
nixnax 142:54d1543e23e5 869 // this is where we insert our web page into the buffer
nixnax 142:54d1543e23e5 870 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 142:54d1543e23e5 871 n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax 142:54d1543e23e5 872 } else if ( (httpGet5 == 'w') && (httpGet6 == 's') ) { // "ws" is a special page for websocket demo
nixnax 142:54d1543e23e5 873 memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax 142:54d1543e23e5 874 n = n + sizeof(webSocketPage)-1; // one less than size
nixnax 142:54d1543e23e5 875 } else {
nixnax 142:54d1543e23e5 876 if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax 142:54d1543e23e5 877
nixnax 142:54d1543e23e5 878 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 142:54d1543e23e5 879 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 142:54d1543e23e5 880 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 142:54d1543e23e5 881 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax 146:a45f49a2b29c 882 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax 142:54d1543e23e5 883 #else
nixnax 142:54d1543e23e5 884 if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax 142:54d1543e23e5 885 n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax 142:54d1543e23e5 886 }
nixnax 142:54d1543e23e5 887 // /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax 146:a45f49a2b29c 888 n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax 142:54d1543e23e5 889 #endif
nixnax 142:54d1543e23e5 890 } else {
nixnax 142:54d1543e23e5 891 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 142:54d1543e23e5 892 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax 142:54d1543e23e5 893 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 142:54d1543e23e5 894 }
nixnax 142:54d1543e23e5 895 }
nixnax 142:54d1543e23e5 896 #define CONTENTLENGTHSIZE 5
nixnax 142:54d1543e23e5 897 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 142:54d1543e23e5 898 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 142:54d1543e23e5 899 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 142:54d1543e23e5 900 return n; // total byte size of our response
nixnax 142:54d1543e23e5 901 }
nixnax 142:54d1543e23e5 902
nixnax 142:54d1543e23e5 903 /// handle TCP data that is not an HTTP get
nixnax 142:54d1543e23e5 904 /// this is the response if we have TCP data but it's not an HTTP GET
nixnax 142:54d1543e23e5 905 /// this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 142:54d1543e23e5 906 /// this could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax 142:54d1543e23e5 907 int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax 142:54d1543e23e5 908 {
nixnax 142:54d1543e23e5 909 int n=0; // number of bytes we have printed so far
nixnax 142:54d1543e23e5 910 if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax 142:54d1543e23e5 911 // this is most likely a websocket push message. you get this when you enter this in your browser console: x.send("my message");
nixnax 142:54d1543e23e5 912 if (0) putsWhileCheckingInput( "Got data from websocket send()\n" );
nixnax 142:54d1543e23e5 913
nixnax 142:54d1543e23e5 914 // for now we simply echo the websocket data back to the client - the client should therefore see an onmessage event
nixnax 142:54d1543e23e5 915 // to display the echoed data in your browser, enter the following into the browser console: x.onmessage = function(msg){ console.log( msg.data ); }
nixnax 142:54d1543e23e5 916 if (1) {
nixnax 142:54d1543e23e5 917 char mask [4];
nixnax 142:54d1543e23e5 918 memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax 142:54d1543e23e5 919 int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax 142:54d1543e23e5 920 if((dataStart[1]&0x80)==0x80) // test if the mask bit is set, which means all data is xor'ed with the mask
nixnax 142:54d1543e23e5 921 for (int i=0; i<websocketMessageSize; i++) dataStart[i+6]^= mask[i%4]; // unmask each byte with one of the mask bytes
nixnax 142:54d1543e23e5 922 dataStart[1] = len-2; // add four extra bytes to the message length because we don't use mask bytes for the send
nixnax 142:54d1543e23e5 923 memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax 142:54d1543e23e5 924 n = len; // our response size remains exactly the same length as what we received
nixnax 142:54d1543e23e5 925 }
nixnax 142:54d1543e23e5 926 } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax 142:54d1543e23e5 927 n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax 142:54d1543e23e5 928 dataStart[1]=0; // we don't have mask bytes on
nixnax 142:54d1543e23e5 929 } else if (v1) putsWhileCheckingInput("TCP data received\n");
nixnax 142:54d1543e23e5 930 return n; // total byte size of our response
nixnax 142:54d1543e23e5 931 }
nixnax 142:54d1543e23e5 932
nixnax 142:54d1543e23e5 933 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 934 /// 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 935 void tcpHandler()
nixnax 142:54d1543e23e5 936 {
nixnax 142:54d1543e23e5 937 // IP header
nixnax 142:54d1543e23e5 938 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 142:54d1543e23e5 939 char * ihl = ipPkt; // bottom 4 bits
nixnax 142:54d1543e23e5 940 char * pktLen = ipPkt+2; // 2 bytes
nixnax 142:54d1543e23e5 941 char * ident = ipPkt+4; // 2 bytes
nixnax 142:54d1543e23e5 942 char * protocol = ipPkt+9; // 1 byte
nixnax 149:969d98f6fb88 943 //char * headercheck= ipPkt+10; // 2 bytes
nixnax 142:54d1543e23e5 944 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 149:969d98f6fb88 945 //char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 142:54d1543e23e5 946 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 142:54d1543e23e5 947 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 142:54d1543e23e5 948
nixnax 142:54d1543e23e5 949 // TCP header
nixnax 142:54d1543e23e5 950 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 149:969d98f6fb88 951 //char * srctcp = tcp + 0; // 2 bytes
nixnax 149:969d98f6fb88 952 //char * dsttcp = tcp + 2; // 2 bytes
nixnax 142:54d1543e23e5 953 char * seqtcp = tcp + 4; // 4 bytes
nixnax 142:54d1543e23e5 954 char * acktcp = tcp + 8; // 4 bytes
nixnax 142:54d1543e23e5 955 char * offset = tcp + 12; // 4 bits
nixnax 142:54d1543e23e5 956 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 142:54d1543e23e5 957 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 142:54d1543e23e5 958 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 142:54d1543e23e5 959
nixnax 142:54d1543e23e5 960 if(ident) {}; // shut up unused variable reference warning
nixnax 142:54d1543e23e5 961 int tcpSize = packetLength - headerSizeIP;
nixnax 142:54d1543e23e5 962 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 142:54d1543e23e5 963 int protocolIP = protocol[0];
nixnax 142:54d1543e23e5 964 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 142:54d1543e23e5 965 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 142:54d1543e23e5 966 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 142:54d1543e23e5 967 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 142:54d1543e23e5 968 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 142:54d1543e23e5 969 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 142:54d1543e23e5 970 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 142:54d1543e23e5 971
nixnax 142:54d1543e23e5 972 // first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax 142:54d1543e23e5 973 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 142:54d1543e23e5 974 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 149:969d98f6fb88 975 ipPkt[0] = 0x45; // short IP packet size to 45
nixnax 142:54d1543e23e5 976 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 142:54d1543e23e5 977 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 142:54d1543e23e5 978 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 142:54d1543e23e5 979 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 142:54d1543e23e5 980
nixnax 142:54d1543e23e5 981 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 142:54d1543e23e5 982 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 142:54d1543e23e5 983 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 142:54d1543e23e5 984 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 142:54d1543e23e5 985 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 142:54d1543e23e5 986
nixnax 142:54d1543e23e5 987 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 142:54d1543e23e5 988
nixnax 142:54d1543e23e5 989 switch ( flagsTCP ) {
nixnax 142:54d1543e23e5 990 case TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 991 return;
nixnax 142:54d1543e23e5 992 case TCP_FLAG_SYN:
nixnax 142:54d1543e23e5 993 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 142:54d1543e23e5 994 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 142:54d1543e23e5 995 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 996 break;
nixnax 142:54d1543e23e5 997 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 142:54d1543e23e5 998 if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax 142:54d1543e23e5 999 flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // set outgoing FIN flag to ask them to close from their side
nixnax 142:54d1543e23e5 1000 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 142:54d1543e23e5 1001 } else {
nixnax 142:54d1543e23e5 1002 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not a web request, send a packet reporting number of received bytes
nixnax 142:54d1543e23e5 1003 }
nixnax 142:54d1543e23e5 1004 break;
nixnax 142:54d1543e23e5 1005 case TCP_FLAG_FIN:
nixnax 142:54d1543e23e5 1006 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1007 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 142:54d1543e23e5 1008 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 142:54d1543e23e5 1009 ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax 142:54d1543e23e5 1010 break;
nixnax 142:54d1543e23e5 1011 default:
nixnax 142:54d1543e23e5 1012 return; // ignore remaining packets
nixnax 142:54d1543e23e5 1013 } // switch
nixnax 142:54d1543e23e5 1014
nixnax 142:54d1543e23e5 1015 // The TCP flag handling is now done
nixnax 142:54d1543e23e5 1016 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 147:0f40005cbc5f 1017 swapIpAddresses(); // swap IP source and destination addresses
nixnax 149:969d98f6fb88 1018 swapIpPorts(); // swap IP source and destination ports
nixnax 142:54d1543e23e5 1019
nixnax 142:54d1543e23e5 1020 acktcp[0]=ack_out>>24;
nixnax 142:54d1543e23e5 1021 acktcp[1]=ack_out>>16;
nixnax 142:54d1543e23e5 1022 acktcp[2]=ack_out>>8;
nixnax 142:54d1543e23e5 1023 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 142:54d1543e23e5 1024 seqtcp[0]=seq_out>>24;
nixnax 142:54d1543e23e5 1025 seqtcp[1]=seq_out>>16;
nixnax 142:54d1543e23e5 1026 seqtcp[2]=seq_out>>8;
nixnax 142:54d1543e23e5 1027 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 142:54d1543e23e5 1028
nixnax 142:54d1543e23e5 1029 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 142:54d1543e23e5 1030
nixnax 142:54d1543e23e5 1031 // increment our outgoing ip packet counter
nixnax 142:54d1543e23e5 1032 ppp.ip.ident++; // get next ident number for our packet
nixnax 142:54d1543e23e5 1033
nixnax 142:54d1543e23e5 1034 // Now we recalculate all the header sizes
nixnax 142:54d1543e23e5 1035 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 142:54d1543e23e5 1036 int newPacketSize = headerSizeIP + tcpSize; // calculate size of the outgoing packet
nixnax 142:54d1543e23e5 1037 pktLen[0] = (newPacketSize>>8);
nixnax 142:54d1543e23e5 1038 pktLen[1]=newPacketSize; // ip total packet size
nixnax 142:54d1543e23e5 1039 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 1040
nixnax 142:54d1543e23e5 1041 // the header is all set up, now do the IP and TCP checksums
nixnax 146:a45f49a2b29c 1042 IpHeaderCheckSum(); // calculate new IP header checksum
nixnax 142:54d1543e23e5 1043
nixnax 142:54d1543e23e5 1044 // now we have to build the so-called 12-byte TCP "pseudo-header" in front of the TCP header (containing some IP header values) in order to correctly calculate the TCP checksum
nixnax 142:54d1543e23e5 1045 // this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax 149:969d98f6fb88 1046 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 142:54d1543e23e5 1047 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 142:54d1543e23e5 1048 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 142:54d1543e23e5 1049 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 142:54d1543e23e5 1050 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 142:54d1543e23e5 1051 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 142:54d1543e23e5 1052 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 142:54d1543e23e5 1053 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 142:54d1543e23e5 1054 // pseudo-header built, now we can calculate TCP checksum
nixnax 142:54d1543e23e5 1055 checksumtcp[0]=0;
nixnax 142:54d1543e23e5 1056 checksumtcp[1]=0;
nixnax 142:54d1543e23e5 1057 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 142:54d1543e23e5 1058 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 142:54d1543e23e5 1059 checksumtcp[1]=pseudoHeaderSum;
nixnax 142:54d1543e23e5 1060 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 147:0f40005cbc5f 1061 // IP and TCP checksums done
nixnax 142:54d1543e23e5 1062 dumpHeaderIP(1); // dump outgoing IP header
nixnax 142:54d1543e23e5 1063 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 142:54d1543e23e5 1064 for (int i=0; i<45*1000/10; i++) { // 45 ms delay before sending frame - a typical internet delay time
nixnax 142:54d1543e23e5 1065 checkPc(); // catch any incoming characters
nixnax 142:54d1543e23e5 1066 wait_us(10); // wait less than 1 character duration at 115200
nixnax 142:54d1543e23e5 1067 }
nixnax 144:01d98cf7738e 1068 sendPppFrame(); // All preparation complete - send the TCP response
nixnax 142:54d1543e23e5 1069 if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
nixnax 142:54d1543e23e5 1070 memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax 142:54d1543e23e5 1071 }
nixnax 142:54d1543e23e5 1072
nixnax 142:54d1543e23e5 1073
nixnax 142:54d1543e23e5 1074 /// dump the TCP data to the debug serial port
nixnax 142:54d1543e23e5 1075 void dumpDataTCP()
nixnax 142:54d1543e23e5 1076 {
nixnax 142:54d1543e23e5 1077 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 142:54d1543e23e5 1078 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 142:54d1543e23e5 1079 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 142:54d1543e23e5 1080 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 142:54d1543e23e5 1081 if (v1) {
nixnax 142:54d1543e23e5 1082 char pbuf[50]; // local print buffer
nixnax 142:54d1543e23e5 1083 checkPc();
nixnax 142:54d1543e23e5 1084 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 142:54d1543e23e5 1085 checkPc();
nixnax 142:54d1543e23e5 1086 putsWhileCheckingInput( pbuf );
nixnax 142:54d1543e23e5 1087 }
nixnax 142:54d1543e23e5 1088 if (dataLen > 0) {
nixnax 142:54d1543e23e5 1089 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 142:54d1543e23e5 1090 putsWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP ); // print the tcp payload data
nixnax 142:54d1543e23e5 1091 putsWhileCheckingInput("\n");
nixnax 142:54d1543e23e5 1092 }
nixnax 142:54d1543e23e5 1093 }
nixnax 142:54d1543e23e5 1094
nixnax 142:54d1543e23e5 1095 /// handle an incoming TCP packet
nixnax 142:54d1543e23e5 1096 void TCPpacket()
nixnax 142:54d1543e23e5 1097 {
nixnax 142:54d1543e23e5 1098 dumpHeaderIP(0); // dump incoming packet header
nixnax 142:54d1543e23e5 1099 dumpHeaderTCP(0); // dump incoming packet header
nixnax 142:54d1543e23e5 1100 if (v2) dumpDataTCP();
nixnax 142:54d1543e23e5 1101 tcpHandler();
nixnax 142:54d1543e23e5 1102 }
nixnax 142:54d1543e23e5 1103
nixnax 142:54d1543e23e5 1104 /// handle the remaining IP protocols by ignoring them
nixnax 142:54d1543e23e5 1105 void otherProtocol()
nixnax 142:54d1543e23e5 1106 {
nixnax 142:54d1543e23e5 1107 debugPrintf("Other IP protocol");
nixnax 142:54d1543e23e5 1108 }
nixnax 142:54d1543e23e5 1109
nixnax 142:54d1543e23e5 1110 /// process an incoming IP packet
nixnax 142:54d1543e23e5 1111 void IPframe()
nixnax 142:54d1543e23e5 1112 {
nixnax 142:54d1543e23e5 1113 int protocol = ppp.pkt.buf[13];
nixnax 142:54d1543e23e5 1114 switch (protocol) {
nixnax 142:54d1543e23e5 1115 case 1:
nixnax 142:54d1543e23e5 1116 ICMPpacket();
nixnax 142:54d1543e23e5 1117 break;
nixnax 142:54d1543e23e5 1118 case 2:
nixnax 142:54d1543e23e5 1119 IGMPpacket();
nixnax 142:54d1543e23e5 1120 break;
nixnax 142:54d1543e23e5 1121 case 17:
nixnax 142:54d1543e23e5 1122 UDPpacket();
nixnax 142:54d1543e23e5 1123 break;
nixnax 142:54d1543e23e5 1124 case 6:
nixnax 142:54d1543e23e5 1125 TCPpacket();
nixnax 142:54d1543e23e5 1126 break;
nixnax 142:54d1543e23e5 1127 default:
nixnax 142:54d1543e23e5 1128 otherProtocol();
nixnax 142:54d1543e23e5 1129 }
nixnax 142:54d1543e23e5 1130 }
nixnax 142:54d1543e23e5 1131
nixnax 142:54d1543e23e5 1132 /// respond to LCP (line configuration protocol) configuration request) by allowing no options
nixnax 142:54d1543e23e5 1133 void LCPconfReq()
nixnax 142:54d1543e23e5 1134 {
nixnax 142:54d1543e23e5 1135 debugPrintf("LCP Config ");
nixnax 142:54d1543e23e5 1136 if (ppp.pkt.buf[7] != 4) {
nixnax 142:54d1543e23e5 1137 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 142:54d1543e23e5 1138 debugPrintf("Reject\n");
nixnax 144:01d98cf7738e 1139 sendPppFrame();
nixnax 142:54d1543e23e5 1140 } else {
nixnax 142:54d1543e23e5 1141 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 142:54d1543e23e5 1142 debugPrintf("Ack\n");
nixnax 144:01d98cf7738e 1143 sendPppFrame();
nixnax 142:54d1543e23e5 1144 debugPrintf("LCP Ask\n");
nixnax 142:54d1543e23e5 1145 ppp.pkt.buf[4]=1; // request no options
nixnax 144:01d98cf7738e 1146 sendPppFrame();
nixnax 142:54d1543e23e5 1147 }
nixnax 142:54d1543e23e5 1148 }
nixnax 142:54d1543e23e5 1149
nixnax 142:54d1543e23e5 1150 /// handle LCP acknowledge packets by ignoring them
nixnax 142:54d1543e23e5 1151 void LCPconfAck()
nixnax 142:54d1543e23e5 1152 {
nixnax 142:54d1543e23e5 1153 debugPrintf("LCP Ack\n");
nixnax 142:54d1543e23e5 1154 }
nixnax 142:54d1543e23e5 1155
nixnax 143:c5019f856a56 1156 /// handle LCP end (disconnect) packets by acknowledging them and by setting ppp.online to false
nixnax 142:54d1543e23e5 1157 void LCPend()
nixnax 142:54d1543e23e5 1158 {
nixnax 142:54d1543e23e5 1159 ppp.pkt.buf[4]=6;
nixnax 144:01d98cf7738e 1160 sendPppFrame(); // acknowledge
nixnax 142:54d1543e23e5 1161 ppp.online=0; // start hunting for connect string again
nixnax 142:54d1543e23e5 1162 pppInitStruct(); // flush the receive buffer
nixnax 143:c5019f856a56 1163 debugPrintf("LCP End (Disconnect from host)\n");
nixnax 142:54d1543e23e5 1164 }
nixnax 142:54d1543e23e5 1165
nixnax 142:54d1543e23e5 1166 /// respond to other LCP requests by ignoring them
nixnax 142:54d1543e23e5 1167 void LCPother()
nixnax 142:54d1543e23e5 1168 {
nixnax 142:54d1543e23e5 1169 debugPrintf("LCP Other\n");
nixnax 142:54d1543e23e5 1170 dumpPPPFrame();
nixnax 142:54d1543e23e5 1171 }
nixnax 142:54d1543e23e5 1172
nixnax 142:54d1543e23e5 1173 /// process incoming LCP packets
nixnax 142:54d1543e23e5 1174 void LCPframe()
nixnax 142:54d1543e23e5 1175 {
nixnax 142:54d1543e23e5 1176 int code = ppp.pkt.buf[4];
nixnax 142:54d1543e23e5 1177 switch (code) {
nixnax 142:54d1543e23e5 1178 case 1:
nixnax 142:54d1543e23e5 1179 LCPconfReq();
nixnax 142:54d1543e23e5 1180 break; // config request
nixnax 142:54d1543e23e5 1181 case 2:
nixnax 142:54d1543e23e5 1182 LCPconfAck();
nixnax 142:54d1543e23e5 1183 break; // config ack
nixnax 142:54d1543e23e5 1184 case 5:
nixnax 142:54d1543e23e5 1185 LCPend();
nixnax 142:54d1543e23e5 1186 break; // end connection
nixnax 142:54d1543e23e5 1187 default:
nixnax 142:54d1543e23e5 1188 LCPother();
nixnax 142:54d1543e23e5 1189 }
nixnax 142:54d1543e23e5 1190 }
nixnax 142:54d1543e23e5 1191
nixnax 142:54d1543e23e5 1192 /// discard packets that are not IP, IPCP, or LCP
nixnax 142:54d1543e23e5 1193 void discardedFrame()
nixnax 142:54d1543e23e5 1194 {
nixnax 142:54d1543e23e5 1195 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 1196 }
nixnax 142:54d1543e23e5 1197
nixnax 142:54d1543e23e5 1198 /// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax 142:54d1543e23e5 1199 void determinePacketType()
nixnax 142:54d1543e23e5 1200 {
nixnax 142:54d1543e23e5 1201 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 142:54d1543e23e5 1202 debugPrintf("byte0 != ff\n");
nixnax 142:54d1543e23e5 1203 return;
nixnax 142:54d1543e23e5 1204 }
nixnax 142:54d1543e23e5 1205 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 142:54d1543e23e5 1206 debugPrintf("byte1 != 3\n");
nixnax 142:54d1543e23e5 1207 return;
nixnax 142:54d1543e23e5 1208 }
nixnax 142:54d1543e23e5 1209 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 142:54d1543e23e5 1210 debugPrintf("byte2 != 21\n");
nixnax 142:54d1543e23e5 1211 return;
nixnax 142:54d1543e23e5 1212 }
nixnax 142:54d1543e23e5 1213 int packetType = ppp.pkt.buf[2];
nixnax 142:54d1543e23e5 1214 switch (packetType) {
nixnax 142:54d1543e23e5 1215 case 0xc0:
nixnax 142:54d1543e23e5 1216 LCPframe();
nixnax 142:54d1543e23e5 1217 break; // link control
nixnax 142:54d1543e23e5 1218 case 0x80:
nixnax 142:54d1543e23e5 1219 IPCPframe();
nixnax 142:54d1543e23e5 1220 break; // IP control
nixnax 142:54d1543e23e5 1221 case 0x00:
nixnax 142:54d1543e23e5 1222 IPframe();
nixnax 142:54d1543e23e5 1223 break; // IP itself
nixnax 142:54d1543e23e5 1224 default:
nixnax 142:54d1543e23e5 1225 discardedFrame();
nixnax 142:54d1543e23e5 1226 }
nixnax 142:54d1543e23e5 1227 }
nixnax 142:54d1543e23e5 1228
nixnax 146:a45f49a2b29c 1229 /// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 146:a45f49a2b29c 1230 void sniff()
nixnax 146:a45f49a2b29c 1231 {
nixnax 146:a45f49a2b29c 1232 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 1233 }
nixnax 146:a45f49a2b29c 1234
nixnax 142:54d1543e23e5 1235 /// scan the PPP serial input stream for frame start markers
nixnax 143:c5019f856a56 1236 void waitForPppFrame()
nixnax 142:54d1543e23e5 1237 {
nixnax 142:54d1543e23e5 1238 while(1) {
nixnax 142:54d1543e23e5 1239 checkPc(); // handle received characters
nixnax 142:54d1543e23e5 1240 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 142:54d1543e23e5 1241 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 142:54d1543e23e5 1242 int rx = pc_getBuf(); // get the character
nixnax 142:54d1543e23e5 1243 if (rx==FRAME_7E) {
nixnax 142:54d1543e23e5 1244 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 142:54d1543e23e5 1245 ppp.firstFrame=0;
nixnax 142:54d1543e23e5 1246 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1247 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 142:54d1543e23e5 1248 } else {
nixnax 142:54d1543e23e5 1249 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 142:54d1543e23e5 1250 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 142:54d1543e23e5 1251 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 142:54d1543e23e5 1252 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax 142:54d1543e23e5 1253 break;
nixnax 142:54d1543e23e5 1254 }
nixnax 142:54d1543e23e5 1255 }
nixnax 142:54d1543e23e5 1256 }
nixnax 142:54d1543e23e5 1257 }
nixnax 142:54d1543e23e5 1258 }
nixnax 142:54d1543e23e5 1259
nixnax 142:54d1543e23e5 1260 /// scan for a connect string ("CLIENT") from the host PC, if found, we set ppp.oline to true, which will the IP packet scanner
nixnax 142:54d1543e23e5 1261 void scanForConnectString()
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 }