PPP-Blinky - Small Internet Protocol Stack using a standard se…

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Nicolas Nackel / Mbed 2 deprecated PPP-Blinky

Small Internet Protocol Stack using a standard serial port.

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@186:7ff62f1c1a16, 2017-09-25 (annotated)

Committer:: nixnax
Date:: Mon Sep 25 01:50:33 2017 +0000
Revision:: 186:7ff62f1c1a16
Parent:: 185:4cd8f91e9d49
Child:: 193:48072570f41d

Latest mbed library - Revision 151.

Who changed what in which revision?

User	Revision	Line number	New contents of line
nixnax	182:f039ec218c9f	1	// PPP-Blinky - "The Most Basic Internet Thing"
nixnax	142:54d1543e23e5	2	// A Tiny HTTP Webserver Using Windows XP/7/8/10/Linux Dial-Up Networking Over A Serial Port.
nixnax	142:54d1543e23e5	3	// Receives UDP packets and responds to ping (ICMP Echo requests)
nixnax	142:54d1543e23e5	4	// WebSocket Service - see https://en.wikipedia.org/wiki/WebSocket
nixnax	142:54d1543e23e5	5
nixnax	142:54d1543e23e5	6	// Copyright 2016/2017 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax	142:54d1543e23e5	7
nixnax	142:54d1543e23e5	8	// Notes and Instructions
nixnax	142:54d1543e23e5	9	// http://bit.ly/PPP-Blinky-Instructions
nixnax	142:54d1543e23e5	10	// http://bit.ly/win-rasdial-config
nixnax	142:54d1543e23e5	11
nixnax	142:54d1543e23e5	12	// Handy reading material
nixnax	142:54d1543e23e5	13	// https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax	142:54d1543e23e5	14	// https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax	142:54d1543e23e5	15	// http://atari.kensclassics.org/wcomlog.htm
nixnax	142:54d1543e23e5	16
nixnax	142:54d1543e23e5	17	// Handy tools
nixnax	142:54d1543e23e5	18	// https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax	142:54d1543e23e5	19	// https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax	142:54d1543e23e5	20	// http://pingtester.net/ - nice tool for high rate ping testing
nixnax	142:54d1543e23e5	21	// http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE), then custom relected-in=1, reflected-out=1
nixnax	142:54d1543e23e5	22	// https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax	142:54d1543e23e5	23	// https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax	142:54d1543e23e5	24	// Windows Powershell invoke-webrequest command - use it to stress test the webserver like this: while (1){ invoke-webrequest -uri 172.10.10.1/x }
nixnax	142:54d1543e23e5	25
nixnax	142:54d1543e23e5	26	// Connecting PPP-Blinky to Linux
nixnax	142:54d1543e23e5	27	// PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax	142:54d1543e23e5	28	// pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax	142:54d1543e23e5	29	// in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax	142:54d1543e23e5	30	// See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax	142:54d1543e23e5	31
nixnax	142:54d1543e23e5	32	// Special pages when PPP-Blinky is running
nixnax	142:54d1543e23e5	33	// 172.10.10.2 root page
nixnax	182:f039ec218c9f	34	// 172.10.10.2/x returns the number of ppp frames sent - this is handy for testing
nixnax	182:f039ec218c9f	35	// 172.10.10.2/xb also returns number of ppp frames sent, but issues a fast refresh meta command. This allows you to use your browser to benchmark page load speed
nixnax	142:54d1543e23e5	36	// 172.10.10.2/ws a simple WebSocket demo
nixnax	182:f039ec218c9f	37	// http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle, showing cross-domain access
nixnax	142:54d1543e23e5	38
nixnax	142:54d1543e23e5	39	// Ok, enough talking, time to check out some code!!
nixnax	142:54d1543e23e5	40
nixnax	142:54d1543e23e5	41	#include "ppp-blinky.h"
nixnax	142:54d1543e23e5	42
nixnax	142:54d1543e23e5	43	// The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax	146:a45f49a2b29c	44	// Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor the debug output.
nixnax	142:54d1543e23e5	45	// Using the second serial port will slow down packet response time
nixnax	142:54d1543e23e5	46	// Note - the LPC11U24 does NOT have a second serial port
nixnax	146:a45f49a2b29c	47
nixnax	183:6d3ba874b267	48	#define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax	142:54d1543e23e5	49
nixnax	142:54d1543e23e5	50	// here we define the OPTIONAL, second debug serial port for various mbed target boards
nixnax	142:54d1543e23e5	51	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	142:54d1543e23e5	52	#if defined(TARGET_LPC1768)
nixnax	179:ba2b2ddd0da5	53	RawSerial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	54	#elif defined(TARGET_NUCLEO_F446RE) \|\| defined(TARGET_NUCLEO_L152RE) \|\| defined(TARGET_NUCLEO_L053R8) \|\| defined(TARGET_NUCLEO_L476RG) \|\| defined(TARGET_NUCLEO_F401RE)
nixnax	179:ba2b2ddd0da5	55	RawSerial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	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	179:ba2b2ddd0da5	59	RawSerial 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	179:ba2b2ddd0da5	62	RawSerial xx(p9, p10); // change this to YOUR board second serial port pin definition - and please send it to me if it works!!!
nixnax	142:54d1543e23e5	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	179:ba2b2ddd0da5	66	#define debugPrintf(x...) xx.printf (x) /* if we have a serial port we can 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	182:f039ec218c9f	77	#define v0 1
nixnax	142:54d1543e23e5	78	#define v1 0
nixnax	142:54d1543e23e5	79	#define v2 0
nixnax	182:f039ec218c9f	80	#define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax	182:f039ec218c9f	81	#define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax	142:54d1543e23e5	82
nixnax	142:54d1543e23e5	83	// this is the webpage we serve when we get an HTTP request to root (/)
nixnax	142:54d1543e23e5	84	// keep size under ~900 bytes to fit into a single PPP packet
nixnax	142:54d1543e23e5	85
nixnax	142:54d1543e23e5	86	const static char rootWebPage[] = "\
nixnax	142:54d1543e23e5	87	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	88	<html>\
nixnax	142:54d1543e23e5	89	<head>\
nixnax	146:a45f49a2b29c	90	<title>mbed PPP-Blinky</title>\r\n\
nixnax	146:a45f49a2b29c	91	<script>\r\n\
nixnax	142:54d1543e23e5	92	window.onload=function(){\
nixnax	142:54d1543e23e5	93	setInterval(function(){function x(){return document.getElementById('w');};\
nixnax	146:a45f49a2b29c	94	x().textContent=parseInt(x().textContent)+1;},100);};\r\n\
nixnax	146:a45f49a2b29c	95	</script>\r\n\
nixnax	142:54d1543e23e5	96	</head>\
nixnax	142:54d1543e23e5	97	<body style=\"font-family: sans-serif; font-size:20px; text-align:center; color:#807070\">\
nixnax	142:54d1543e23e5	98	<h1>mbed PPP-Blinky Up and Running</h1>\
nixnax	142:54d1543e23e5	99	<h1 id=\"w\">0</h1>\
nixnax	142:54d1543e23e5	100	<h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax	142:54d1543e23e5	101	<h1><a href=\"/ws\">WebSocket Demo</a></h1>\
nixnax	142:54d1543e23e5	102	<h1><a href=\"/x\">Benchmark 1</a></h1>\
nixnax	142:54d1543e23e5	103	<h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax	142:54d1543e23e5	104	<h1><a href=\"http://jsfiddle.net/d26cyuh2/\">JSFiddle Demo</a></h1>\
nixnax	142:54d1543e23e5	105	</body>\
nixnax	146:a45f49a2b29c	106	</html>\r\n"; // size = 644 bytes plus 1 null byte = 645 bytes
nixnax	142:54d1543e23e5	107
nixnax	167:ff8a2d8beeb1	108	// this is a websocket demo html page we serve when GET /ws is requested
nixnax	142:54d1543e23e5	109	const static char webSocketPage[] = "\
nixnax	142:54d1543e23e5	110	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	111	<html>\
nixnax	142:54d1543e23e5	112	<head>\
nixnax	142:54d1543e23e5	113	<title>mbed PPP-Blinky</title>\
nixnax	142:54d1543e23e5	114	<script>\
nixnax	142:54d1543e23e5	115	window.onload=function(){\
nixnax	142:54d1543e23e5	116	var url=\"ws://172.10.10.2\";\
nixnax	142:54d1543e23e5	117	var sts=document.getElementById(\"sts\");\
nixnax	142:54d1543e23e5	118	var btn=document.getElementById(\"btn\");\
nixnax	142:54d1543e23e5	119	var ctr=0;\
nixnax	142:54d1543e23e5	120	function show(text){sts.textContent=text;}\
nixnax	142:54d1543e23e5	121	btn.onclick=function(){\
nixnax	142:54d1543e23e5	122	if(btn.textContent==\"Connect\"){\
nixnax	142:54d1543e23e5	123	x=new WebSocket(url);\
nixnax	142:54d1543e23e5	124	x.onopen=function(){\
nixnax	142:54d1543e23e5	125	show(\"Connected to : \"+url);\
nixnax	142:54d1543e23e5	126	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	127	};\
nixnax	142:54d1543e23e5	128	x.onclose=function(){show(\"closed\");};\
nixnax	142:54d1543e23e5	129	x.onmessage=function(msg){show(\"PPP-Blinky Sent: \\\"\"+msg.data+\"\\\"\");};\
nixnax	142:54d1543e23e5	130	} else {\
nixnax	142:54d1543e23e5	131	x.send(ctr);\
nixnax	142:54d1543e23e5	132	ctr=ctr+1;\
nixnax	142:54d1543e23e5	133	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	134	}\
nixnax	142:54d1543e23e5	135	};\
nixnax	142:54d1543e23e5	136	};\
nixnax	142:54d1543e23e5	137	</script>\
nixnax	142:54d1543e23e5	138	<body style=\"font-family: sans-serif; font-size:25px; color:#807070\">\
nixnax	142:54d1543e23e5	139	<h1>PPP-Blinky WebSocket Test</h1>\
nixnax	142:54d1543e23e5	140	<div id=\"sts\">Idle</div>\
nixnax	142:54d1543e23e5	141	<button id=\"btn\" style=\"font-size: 100%; margin-top: 55px; margin-bottom: 55px;\">Connect</button>\
nixnax	142:54d1543e23e5	142	<h4><a href=\"/\">PPP-Blinky home</a></h4>\
nixnax	142:54d1543e23e5	143	</body>\
nixnax	142:54d1543e23e5	144	</html>"; // size = 916 bytes + 1 null byte = 917 bytes
nixnax	142:54d1543e23e5	145
nixnax	142:54d1543e23e5	146	// The serial port on your mbed hardware. Your PC should be configured to view this port as a standard dial-up networking modem.
nixnax	142:54d1543e23e5	147	// On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax	142:54d1543e23e5	148	// The modem baud rate should be set to 115200 baud
nixnax	142:54d1543e23e5	149	// See instructions at the top.
nixnax	142:54d1543e23e5	150	// On a typical mbed hardware platform this serial port is a USB virtual com port (VCP) and the USB serial driver is supplied by the board vendor.
nixnax	179:ba2b2ddd0da5	151	RawSerial pc (USBTX, USBRX); // 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	pppType ppp; // our global - definitely not thread safe
nixnax	142:54d1543e23e5	159
nixnax	142:54d1543e23e5	160	/// Initialize the ppp structure and clear the receive buffer
nixnax	142:54d1543e23e5	161	void pppInitStruct()
nixnax	142:54d1543e23e5	162	{
nixnax	142:54d1543e23e5	163	memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax	142:54d1543e23e5	164	ppp.online=0;
nixnax	142:54d1543e23e5	165	ppp.rx.tail=0;
nixnax	142:54d1543e23e5	166	ppp.rx.rtail=0;
nixnax	142:54d1543e23e5	167	ppp.rx.head=0;
nixnax	142:54d1543e23e5	168	ppp.rx.buflevel=0;
nixnax	142:54d1543e23e5	169	ppp.pkt.len=0;
nixnax	154:18b2bd92f557	170	ppp.ipData.ident=10000; // easy to recognize in ip packet dumps
nixnax	142:54d1543e23e5	171	ppp.ledState=0;
nixnax	142:54d1543e23e5	172	ppp.hdlc.frameStartIndex=0;
nixnax	146:a45f49a2b29c	173	ppp.responseCounter=0;
nixnax	142:54d1543e23e5	174	ppp.firstFrame=1;
nixnax	175:b4e6f8a6fe00	175	ppp.ppp = (pppHeaderType *)ppp.pkt.buf; // pointer to ppp header
nixnax	175:b4e6f8a6fe00	176	ppp.ip = (ipHeaderType *)(ppp.pkt.buf+4); // pointer to IP header
nixnax	142:54d1543e23e5	177	}
nixnax	142:54d1543e23e5	178
nixnax	142:54d1543e23e5	179	/// Toggle the LED on every second PPP packet received
nixnax	142:54d1543e23e5	180	void led1Toggle()
nixnax	142:54d1543e23e5	181	{
nixnax	142:54d1543e23e5	182	led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax	143:c5019f856a56	183	ppp.ledState++;
nixnax	142:54d1543e23e5	184	}
nixnax	142:54d1543e23e5	185
nixnax	179:ba2b2ddd0da5	186	/// Returns 1 after a connect message, 0 at startup or after a disconnect message
nixnax	150:3366bf3d294e	187	int connectedPpp()
nixnax	142:54d1543e23e5	188	{
nixnax	142:54d1543e23e5	189	return ppp.online;
nixnax	143:c5019f856a56	190	}
nixnax	142:54d1543e23e5	191
nixnax	179:ba2b2ddd0da5	192	/// Previously used to check for characters in receive buffer.
nixnax	179:ba2b2ddd0da5	193	/// Now just a stub.
nixnax	179:ba2b2ddd0da5	194	void checkPc() {};
nixnax	179:ba2b2ddd0da5	195
nixnax	179:ba2b2ddd0da5	196	/// PPP serial port receive interrupt handler.
nixnax	143:c5019f856a56	197	/// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax	143:c5019f856a56	198	/// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax	179:ba2b2ddd0da5	199	void pppReceiveHandler()
nixnax	142:54d1543e23e5	200	{
nixnax	142:54d1543e23e5	201	char ch;
nixnax	179:ba2b2ddd0da5	202	while ( pc.readable() ) {
nixnax	142:54d1543e23e5	203	int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax	142:54d1543e23e5	204	if ( hd == ppp.rx.rtail ) {
nixnax	142:54d1543e23e5	205	debugPrintf("\nReceive buffer full\n");
nixnax	142:54d1543e23e5	206	return;
nixnax	142:54d1543e23e5	207	}
nixnax	142:54d1543e23e5	208	ch = pc.getc(); // read new character
nixnax	142:54d1543e23e5	209	ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax	142:54d1543e23e5	210	if ( ppp.online == 0 ) {
nixnax	142:54d1543e23e5	211	if (ch == 0x7E) {
nixnax	142:54d1543e23e5	212	ppp.online = 1;
nixnax	142:54d1543e23e5	213	}
nixnax	142:54d1543e23e5	214	}
nixnax	142:54d1543e23e5	215	ppp.rx.head = hd; // update head pointer
nixnax	142:54d1543e23e5	216	ppp.rx.buflevel++;
nixnax	142:54d1543e23e5	217	}
nixnax	142:54d1543e23e5	218	}
nixnax	142:54d1543e23e5	219
nixnax	142:54d1543e23e5	220	/// print to debug port while checking for incoming characters
nixnax	142:54d1543e23e5	221	void putcWhileCheckingInput( char outByte )
nixnax	142:54d1543e23e5	222	{
nixnax	142:54d1543e23e5	223	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	142:54d1543e23e5	224	checkPc();
nixnax	142:54d1543e23e5	225	debugPutc( outByte );
nixnax	142:54d1543e23e5	226	checkPc();
nixnax	142:54d1543e23e5	227	#endif
nixnax	142:54d1543e23e5	228	}
nixnax	142:54d1543e23e5	229
nixnax	142:54d1543e23e5	230	/// puts to debug port while checking the PPP input stream
nixnax	142:54d1543e23e5	231	void putsWhileCheckingInput( char * data )
nixnax	142:54d1543e23e5	232	{
nixnax	142:54d1543e23e5	233	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	142:54d1543e23e5	234	char * nextChar = data;
nixnax	142:54d1543e23e5	235	while( *nextChar != 0 ) {
nixnax	142:54d1543e23e5	236	putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax	142:54d1543e23e5	237	nextChar++;
nixnax	142:54d1543e23e5	238	}
nixnax	142:54d1543e23e5	239	#endif
nixnax	142:54d1543e23e5	240	}
nixnax	142:54d1543e23e5	241
nixnax	145:098b6ed2f7f2	242	/// Initialize the PPP FCS (frame check sequence) total
nixnax	145:098b6ed2f7f2	243	void fcsReset()
nixnax	142:54d1543e23e5	244	{
nixnax	145:098b6ed2f7f2	245	ppp.fcs=0xffff; // crc restart
nixnax	142:54d1543e23e5	246	}
nixnax	142:54d1543e23e5	247
nixnax	145:098b6ed2f7f2	248	/// update the cumulative PPP FCS (frame check sequence)
nixnax	145:098b6ed2f7f2	249	void fcsDo(int x)
nixnax	142:54d1543e23e5	250	{
nixnax	142:54d1543e23e5	251	for (int i=0; i<8; i++) {
nixnax	145:098b6ed2f7f2	252	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1; // crc calculator
nixnax	142:54d1543e23e5	253	x>>=1;
nixnax	142:54d1543e23e5	254	}
nixnax	142:54d1543e23e5	255	checkPc(); // handle input
nixnax	142:54d1543e23e5	256	}
nixnax	142:54d1543e23e5	257
nixnax	145:098b6ed2f7f2	258	/// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax	145:098b6ed2f7f2	259	int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax	142:54d1543e23e5	260	{
nixnax	145:098b6ed2f7f2	261	fcsReset();
nixnax	145:098b6ed2f7f2	262	for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax	145:098b6ed2f7f2	263	return ppp.fcs;
nixnax	142:54d1543e23e5	264	}
nixnax	142:54d1543e23e5	265
nixnax	142:54d1543e23e5	266	/// Get one character from our received PPP buffer
nixnax	142:54d1543e23e5	267	int pc_getBuf()
nixnax	142:54d1543e23e5	268	{
nixnax	142:54d1543e23e5	269	int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax	142:54d1543e23e5	270	ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax	142:54d1543e23e5	271	ppp.rx.buflevel--;
nixnax	142:54d1543e23e5	272	return x;
nixnax	142:54d1543e23e5	273	}
nixnax	142:54d1543e23e5	274
nixnax	142:54d1543e23e5	275	/// Dump a PPP frame to the debug serial port
nixnax	142:54d1543e23e5	276	/// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax	142:54d1543e23e5	277	/// Capture the frame's hex output in your terminal program and save as a text file
nixnax	164:c3de3d212c4b	278	/// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax	142:54d1543e23e5	279	void dumpPPPFrame()
nixnax	142:54d1543e23e5	280	{
nixnax	142:54d1543e23e5	281	char pbuf[30];
nixnax	142:54d1543e23e5	282	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	142:54d1543e23e5	283	checkPc();
nixnax	142:54d1543e23e5	284	sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax	142:54d1543e23e5	285	checkPc();
nixnax	142:54d1543e23e5	286	putsWhileCheckingInput(pbuf);
nixnax	142:54d1543e23e5	287	}
nixnax	142:54d1543e23e5	288	checkPc();
nixnax	142:54d1543e23e5	289	sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax	142:54d1543e23e5	290	checkPc();
nixnax	142:54d1543e23e5	291	putsWhileCheckingInput(pbuf);
nixnax	142:54d1543e23e5	292	}
nixnax	142:54d1543e23e5	293
nixnax	142:54d1543e23e5	294	/// Process a received PPP frame
nixnax	142:54d1543e23e5	295	void processPPPFrame(int start, int end)
nixnax	142:54d1543e23e5	296	{
nixnax	142:54d1543e23e5	297	led1Toggle(); // change led1 state on every frame we receive
nixnax	142:54d1543e23e5	298	if(start==end) {
nixnax	142:54d1543e23e5	299	return; // empty frame
nixnax	142:54d1543e23e5	300	}
nixnax	145:098b6ed2f7f2	301	fcsReset();
nixnax	142:54d1543e23e5	302	char * dest = ppp.pkt.buf;
nixnax	142:54d1543e23e5	303	ppp.pkt.len=0;
nixnax	142:54d1543e23e5	304	int unstuff=0;
nixnax	142:54d1543e23e5	305	int idx = start;
nixnax	142:54d1543e23e5	306	while(1) {
nixnax	142:54d1543e23e5	307	checkPc();
nixnax	142:54d1543e23e5	308	if (unstuff==0) {
nixnax	142:54d1543e23e5	309	if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax	142:54d1543e23e5	310	else {
nixnax	142:54d1543e23e5	311	*dest = ppp.rx.buf[idx];
nixnax	142:54d1543e23e5	312	ppp.pkt.len++;
nixnax	142:54d1543e23e5	313	dest++;
nixnax	145:098b6ed2f7f2	314	fcsDo(ppp.rx.buf[idx]);
nixnax	142:54d1543e23e5	315	}
nixnax	142:54d1543e23e5	316	} else { // unstuff characters prefixed with 0x7d
nixnax	142:54d1543e23e5	317	*dest = ppp.rx.buf[idx]^0x20;
nixnax	142:54d1543e23e5	318	ppp.pkt.len++;
nixnax	142:54d1543e23e5	319	dest++;
nixnax	145:098b6ed2f7f2	320	fcsDo(ppp.rx.buf[idx]^0x20);
nixnax	142:54d1543e23e5	321	unstuff=0;
nixnax	142:54d1543e23e5	322	}
nixnax	142:54d1543e23e5	323	idx = (idx+1) & (RXBUFLEN-1);
nixnax	142:54d1543e23e5	324	if (idx == end) break;
nixnax	142:54d1543e23e5	325	}
nixnax	145:098b6ed2f7f2	326	ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax	142:54d1543e23e5	327	if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax	142:54d1543e23e5	328	if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax	142:54d1543e23e5	329	determinePacketType();
nixnax	142:54d1543e23e5	330	} else {
nixnax	142:54d1543e23e5	331	#define REPORT_FCS_ERROR_YES
nixnax	142:54d1543e23e5	332	#ifdef REPORT_FCS_ERROR_YES
nixnax	142:54d1543e23e5	333	char pbuf[50]; // local print buffer
nixnax	142:54d1543e23e5	334	checkPc();
nixnax	142:54d1543e23e5	335	sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax	142:54d1543e23e5	336	checkPc();
nixnax	142:54d1543e23e5	337	putsWhileCheckingInput( pbuf );
nixnax	142:54d1543e23e5	338	if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax	142:54d1543e23e5	339	#endif
nixnax	142:54d1543e23e5	340	}
nixnax	142:54d1543e23e5	341	}
nixnax	142:54d1543e23e5	342
nixnax	142:54d1543e23e5	343	/// output a character to the PPP port while checking for incoming characters
nixnax	142:54d1543e23e5	344	void pcPutcWhileCheckingInput(int ch)
nixnax	142:54d1543e23e5	345	{
nixnax	142:54d1543e23e5	346	checkPc(); // check input
nixnax	142:54d1543e23e5	347	pc.putc(ch);
nixnax	142:54d1543e23e5	348	checkPc();
nixnax	142:54d1543e23e5	349	}
nixnax	142:54d1543e23e5	350
nixnax	142:54d1543e23e5	351	/// do PPP HDLC-like handling of special (flag) characters
nixnax	143:c5019f856a56	352	void hdlcPut(int ch)
nixnax	142:54d1543e23e5	353	{
nixnax	142:54d1543e23e5	354	if ( (ch<0x20) \|\| (ch==0x7d) \|\| (ch==0x7e) ) {
nixnax	142:54d1543e23e5	355	pcPutcWhileCheckingInput(0x7d);
nixnax	142:54d1543e23e5	356	pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax	142:54d1543e23e5	357	} else {
nixnax	142:54d1543e23e5	358	pcPutcWhileCheckingInput(ch);
nixnax	142:54d1543e23e5	359	}
nixnax	142:54d1543e23e5	360	}
nixnax	142:54d1543e23e5	361
nixnax	142:54d1543e23e5	362	/// send a PPP frame in HDLC format
nixnax	144:01d98cf7738e	363	void sendPppFrame()
nixnax	143:c5019f856a56	364	{
nixnax	172:449dd7a28955	365	ppp.responseCounter++; // count the number of ppp frames we send
nixnax	145:098b6ed2f7f2	366	int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax	142:54d1543e23e5	367	ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax	142:54d1543e23e5	368	ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax	142:54d1543e23e5	369	pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax	142:54d1543e23e5	370	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	142:54d1543e23e5	371	wait_us(86); // wait one character time
nixnax	142:54d1543e23e5	372	checkPc();
nixnax	142:54d1543e23e5	373	hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax	142:54d1543e23e5	374	}
nixnax	142:54d1543e23e5	375	pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax	142:54d1543e23e5	376	}
nixnax	142:54d1543e23e5	377
nixnax	143:c5019f856a56	378	/// 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	379	int bufferToIP(char * buffer)
nixnax	143:c5019f856a56	380	{
nixnax	143:c5019f856a56	381	int result=0;
nixnax	143:c5019f856a56	382	for(int i=0; i<4; i++) result = (result<<8)\|(*buffer++ & 0xff);
nixnax	143:c5019f856a56	383	return result;
nixnax	143:c5019f856a56	384	}
nixnax	143:c5019f856a56	385
nixnax	177:dab9e685af53	386	/// convert 4-byte ip address to 32-bit
nixnax	179:ba2b2ddd0da5	387	unsigned int ip( int a, int b, int c, int d)
nixnax	179:ba2b2ddd0da5	388	{
nixnax	177:dab9e685af53	389	return a<<24 \| b<<16 \| c<<8 \| d;
nixnax	177:dab9e685af53	390	}
nixnax	177:dab9e685af53	391
nixnax	142:54d1543e23e5	392	/// handle IPCP configuration requests
nixnax	142:54d1543e23e5	393	void ipcpConfigRequestHandler()
nixnax	142:54d1543e23e5	394	{
nixnax	142:54d1543e23e5	395	debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax	173:6774a0c851c4	396	if(ppp.ipcp->request[0]==3) {
nixnax	143:c5019f856a56	397	ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax	173:6774a0c851c4	398	debugPrintf("Host IP = %d.%d.%d.%d (%08x)\n", ppp.ipcp->request[2],ppp.ipcp->request[3],ppp.ipcp->request[4],ppp.ipcp->request[5],ppp.hostIP);
nixnax	143:c5019f856a56	399	}
nixnax	143:c5019f856a56	400
nixnax	167:ff8a2d8beeb1	401	ppp.ipcp->code=2; // change code to ack
nixnax	144:01d98cf7738e	402	sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax	142:54d1543e23e5	403
nixnax	142:54d1543e23e5	404	debugPrintf("Our IPCP Ask (no options)\n");
nixnax	167:ff8a2d8beeb1	405	ppp.ipcp->code=1; // change code to request
nixnax	167:ff8a2d8beeb1	406	ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax	167:ff8a2d8beeb1	407	ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax	144:01d98cf7738e	408	sendPppFrame(); // send our request
nixnax	142:54d1543e23e5	409	}
nixnax	142:54d1543e23e5	410
nixnax	142:54d1543e23e5	411	/// handle IPCP acknowledge (do nothing)
nixnax	142:54d1543e23e5	412	void ipcpAckHandler()
nixnax	142:54d1543e23e5	413	{
nixnax	142:54d1543e23e5	414	debugPrintf("Their IPCP Grant\n");
nixnax	142:54d1543e23e5	415	}
nixnax	142:54d1543e23e5	416
nixnax	143:c5019f856a56	417	/// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax	143:c5019f856a56	418	/// 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	419	void ipcpNackHandler()
nixnax	142:54d1543e23e5	420	{
nixnax	146:a45f49a2b29c	421	debugPrintf("Their IPCP Nack\n");
nixnax	173:6774a0c851c4	422	if (ppp.ipcp->request[0]==3) { // check if the NACK contains an IP address parameter
nixnax	167:ff8a2d8beeb1	423	ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax	144:01d98cf7738e	424	sendPppFrame(); // let's request this IP address as ours
nixnax	143:c5019f856a56	425	debugPrintf("Our IPCP ACK (received an IP)\n");
nixnax	146:a45f49a2b29c	426	} else { // if it's not an IP nack we ignore it
nixnax	146:a45f49a2b29c	427	debugPrintf("IPCP Nack Ignored\n");
nixnax	146:a45f49a2b29c	428	}
nixnax	142:54d1543e23e5	429	}
nixnax	142:54d1543e23e5	430
nixnax	142:54d1543e23e5	431	/// handle all other IPCP requests (by ignoring them)
nixnax	142:54d1543e23e5	432	void ipcpDefaultHandler()
nixnax	142:54d1543e23e5	433	{
nixnax	142:54d1543e23e5	434	debugPrintf("Their IPCP Other\n");
nixnax	142:54d1543e23e5	435	}
nixnax	142:54d1543e23e5	436
nixnax	142:54d1543e23e5	437	/// process an incoming IPCP packet
nixnax	142:54d1543e23e5	438	void IPCPframe()
nixnax	142:54d1543e23e5	439	{
nixnax	167:ff8a2d8beeb1	440	int action = ppp.ipcp->code; // packet type is here
nixnax	167:ff8a2d8beeb1	441	switch (action) {
nixnax	142:54d1543e23e5	442	case 1:
nixnax	142:54d1543e23e5	443	ipcpConfigRequestHandler();
nixnax	142:54d1543e23e5	444	break;
nixnax	142:54d1543e23e5	445	case 2:
nixnax	142:54d1543e23e5	446	ipcpAckHandler();
nixnax	142:54d1543e23e5	447	break;
nixnax	142:54d1543e23e5	448	case 3:
nixnax	142:54d1543e23e5	449	ipcpNackHandler();
nixnax	142:54d1543e23e5	450	break;
nixnax	142:54d1543e23e5	451	default:
nixnax	142:54d1543e23e5	452	ipcpDefaultHandler();
nixnax	142:54d1543e23e5	453	}
nixnax	142:54d1543e23e5	454	}
nixnax	142:54d1543e23e5	455
nixnax	142:54d1543e23e5	456	/// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax	161:d59f778bc8ab	457	unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax	142:54d1543e23e5	458	{
nixnax	159:4d1bf96a59cd	459	unsigned int i,hi,lo;
nixnax	142:54d1543e23e5	460	unsigned char placeHolder;
nixnax	161:d59f778bc8ab	461	if (restart) ppp.sum=0;
nixnax	142:54d1543e23e5	462	if (len&1) {
nixnax	142:54d1543e23e5	463	placeHolder = ptr[len];
nixnax	142:54d1543e23e5	464	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	465	}
nixnax	142:54d1543e23e5	466	i=0;
nixnax	142:54d1543e23e5	467	while ( i<len ) {
nixnax	142:54d1543e23e5	468	checkPc();
nixnax	142:54d1543e23e5	469	hi = ptr[i++];
nixnax	142:54d1543e23e5	470	lo = ptr[i++];
nixnax	159:4d1bf96a59cd	471	ppp.sum = ppp.sum + ((hi<<8)\|lo);
nixnax	142:54d1543e23e5	472	}
nixnax	142:54d1543e23e5	473	if (len&1) {
nixnax	142:54d1543e23e5	474	ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax	142:54d1543e23e5	475	}
nixnax	159:4d1bf96a59cd	476	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax	159:4d1bf96a59cd	477	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax	159:4d1bf96a59cd	478	return ~ppp.sum;
nixnax	142:54d1543e23e5	479	}
nixnax	142:54d1543e23e5	480
nixnax	142:54d1543e23e5	481	/// perform the checksum on an IP header
nixnax	146:a45f49a2b29c	482	void IpHeaderCheckSum()
nixnax	142:54d1543e23e5	483	{
nixnax	161:d59f778bc8ab	484	ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax	161:d59f778bc8ab	485	int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax	161:d59f778bc8ab	486	unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax	161:d59f778bc8ab	487	ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax	146:a45f49a2b29c	488	}
nixnax	146:a45f49a2b29c	489
nixnax	147:0f40005cbc5f	490	/// swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	491	void swapIpAddresses()
nixnax	147:0f40005cbc5f	492	{
nixnax	162:594729c0e5c1	493	unsigned int tempHold;
nixnax	162:594729c0e5c1	494	tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax	162:594729c0e5c1	495	ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax	162:594729c0e5c1	496	ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax	147:0f40005cbc5f	497	}
nixnax	147:0f40005cbc5f	498
nixnax	149:969d98f6fb88	499	/// swap the IP source and destination ports
nixnax	149:969d98f6fb88	500	void swapIpPorts()
nixnax	149:969d98f6fb88	501	{
nixnax	173:6774a0c851c4	502	int headerSizeIP = 4 * (ppp.ip->headerLength); // calculate size of IP header
nixnax	173:6774a0c851c4	503	char * ipSrcPort = ppp.ipStart + headerSizeIP + 0; // ip source port location
nixnax	173:6774a0c851c4	504	char * ipDstPort = ppp.ipStart + headerSizeIP + 2; // ip destin port location
nixnax	149:969d98f6fb88	505	char tempHold[2];
nixnax	149:969d98f6fb88	506	memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax	149:969d98f6fb88	507	memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax	149:969d98f6fb88	508	memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax	149:969d98f6fb88	509	}
nixnax	149:969d98f6fb88	510
nixnax	170:3d3b2126181c	511	/// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax	170:3d3b2126181c	512	void checkSumPseudoHeader( unsigned int packetLength )
nixnax	170:3d3b2126181c	513	{
nixnax	170:3d3b2126181c	514	// this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax	170:3d3b2126181c	515	pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax	170:3d3b2126181c	516	pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax	170:3d3b2126181c	517	pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax	170:3d3b2126181c	518	pseudoHeader.zero = 0; // zero byte
nixnax	170:3d3b2126181c	519	pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax	170:3d3b2126181c	520	pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax	170:3d3b2126181c	521	dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax	170:3d3b2126181c	522	}
nixnax	170:3d3b2126181c	523
nixnax	171:46b36d4edd1d	524	/// initialize an IP packet to send
nixnax	171:46b36d4edd1d	525	void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax	171:46b36d4edd1d	526	{
nixnax	171:46b36d4edd1d	527	ppp.ppp->address = 0xff;
nixnax	171:46b36d4edd1d	528	ppp.ppp->control = 3;
nixnax	171:46b36d4edd1d	529	ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax	171:46b36d4edd1d	530	ppp.ip->version = 4;
nixnax	171:46b36d4edd1d	531	ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax	171:46b36d4edd1d	532	ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax	171:46b36d4edd1d	533	ppp.ip->dontFragment=1;
nixnax	171:46b36d4edd1d	534	ppp.ip->ttl=128;
nixnax	171:46b36d4edd1d	535	ppp.ip->protocol = protocol; // udp
nixnax	171:46b36d4edd1d	536	ppp.ip->srcAdrR = __REV(srcIp);
nixnax	171:46b36d4edd1d	537	ppp.ip->dstAdrR = __REV(dstIp);
nixnax	171:46b36d4edd1d	538	ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax	171:46b36d4edd1d	539	ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax	171:46b36d4edd1d	540	ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax	171:46b36d4edd1d	541	}
nixnax	171:46b36d4edd1d	542
nixnax	171:46b36d4edd1d	543
nixnax	171:46b36d4edd1d	544	/// Build a UDP packet from scratch
nixnax	171:46b36d4edd1d	545	void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax	171:46b36d4edd1d	546	{
nixnax	171:46b36d4edd1d	547	struct {
nixnax	171:46b36d4edd1d	548	unsigned int ipAll; // length of entire ip packet
nixnax	171:46b36d4edd1d	549	unsigned int ipHeader; // length of ip header
nixnax	171:46b36d4edd1d	550	unsigned int udpAll; // length of entire udp packet
nixnax	171:46b36d4edd1d	551	unsigned int udpData; // length of udp data segment
nixnax	171:46b36d4edd1d	552	} len;
nixnax	171:46b36d4edd1d	553	len.ipHeader = 20; // ip header length
nixnax	171:46b36d4edd1d	554	len.udpData = msgLen; // udp data size
nixnax	171:46b36d4edd1d	555	len.udpAll = len.udpData+8; // update local udp packet length
nixnax	171:46b36d4edd1d	556	len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax	171:46b36d4edd1d	557	initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax	171:46b36d4edd1d	558	ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax	171:46b36d4edd1d	559	ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax	171:46b36d4edd1d	560	memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax	171:46b36d4edd1d	561	ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax	171:46b36d4edd1d	562	ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	563	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	564	checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	565	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	566	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	567	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	568	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	569	}
nixnax	171:46b36d4edd1d	570
nixnax	146:a45f49a2b29c	571	/// Process an incoming UDP packet.
nixnax	146:a45f49a2b29c	572	/// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax	146:a45f49a2b29c	573	void UDPpacket()
nixnax	146:a45f49a2b29c	574	{
nixnax	163:d1b4328e9f08	575	struct {
nixnax	163:d1b4328e9f08	576	unsigned int all; // length of entire ip packet
nixnax	163:d1b4328e9f08	577	unsigned int header; // length of ip header
nixnax	163:d1b4328e9f08	578	} ipLength;
nixnax	163:d1b4328e9f08	579
nixnax	163:d1b4328e9f08	580	struct {
nixnax	165:c47826d07e0d	581	unsigned int all; // length of entire udp packet
nixnax	163:d1b4328e9f08	582	unsigned int data; // length of udp data segment
nixnax	163:d1b4328e9f08	583	} udpLength;
nixnax	163:d1b4328e9f08	584
nixnax	163:d1b4328e9f08	585	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	163:d1b4328e9f08	586	ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	171:46b36d4edd1d	587	udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax	163:d1b4328e9f08	588	udpLength.data = udpLength.all - 8; // size of udp data
nixnax	147:0f40005cbc5f	589
nixnax	146:a45f49a2b29c	590	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	171:46b36d4edd1d	591	char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax	171:46b36d4edd1d	592	char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax	163:d1b4328e9f08	593
nixnax	171:46b36d4edd1d	594	unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax	171:46b36d4edd1d	595	unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax	163:d1b4328e9f08	596
nixnax	163:d1b4328e9f08	597	if(v0) {
nixnax	163:d1b4328e9f08	598	debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax	163:d1b4328e9f08	599	debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax	163:d1b4328e9f08	600	debugPrintf("Len %03d", udpLength);
nixnax	163:d1b4328e9f08	601	}
nixnax	146:a45f49a2b29c	602	if (v1) {
nixnax	163:d1b4328e9f08	603	int printSize = udpLength.data;
nixnax	146:a45f49a2b29c	604	if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax	146:a45f49a2b29c	605	for (int i=0; i<printSize; i++) {
nixnax	163:d1b4328e9f08	606	char ch = ppp.udp->data[i];
nixnax	146:a45f49a2b29c	607	if (ch>31 && ch<127) {
nixnax	146:a45f49a2b29c	608	debugPrintf("%c", ch);
nixnax	146:a45f49a2b29c	609	} else {
nixnax	146:a45f49a2b29c	610	debugPrintf("_");
nixnax	146:a45f49a2b29c	611	}
nixnax	146:a45f49a2b29c	612	}
nixnax	146:a45f49a2b29c	613	}
nixnax	146:a45f49a2b29c	614	if (v0) debugPrintf("\n");
nixnax	146:a45f49a2b29c	615	#endif
nixnax	163:d1b4328e9f08	616	int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax	163:d1b4328e9f08	617	int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax	146:a45f49a2b29c	618	if ( (echoFound) \|\| (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax	146:a45f49a2b29c	619	if (echoFound) {
nixnax	171:46b36d4edd1d	620	swapIpAddresses(); // swap IP source and destination
nixnax	171:46b36d4edd1d	621	swapIpPorts(); // swap IP source and destination ports
nixnax	163:d1b4328e9f08	622	memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax	170:3d3b2126181c	623	int n=0;
nixnax	170:3d3b2126181c	624	n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax	168:c77eb908042a	625	udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax	171:46b36d4edd1d	626	// we may have changed data length, update all the lengths
nixnax	171:46b36d4edd1d	627	udpLength.all = udpLength.data+8; // update local udp packet length
nixnax	171:46b36d4edd1d	628	ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax	171:46b36d4edd1d	629	ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax	171:46b36d4edd1d	630	ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax	171:46b36d4edd1d	631	ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	632	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	633	checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	634	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	635	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	636	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	637	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	638	} else if ( testFound ) {
nixnax	171:46b36d4edd1d	639	unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax	171:46b36d4edd1d	640	unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax	171:46b36d4edd1d	641	unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax	171:46b36d4edd1d	642	unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax	172:449dd7a28955	643	int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter);
nixnax	171:46b36d4edd1d	644	sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax	146:a45f49a2b29c	645	}
nixnax	146:a45f49a2b29c	646	}
nixnax	142:54d1543e23e5	647	}
nixnax	142:54d1543e23e5	648
nixnax	174:e5a3f16421a5	649	/// UDP demo that sends a udp packet containing a character received from the second debug serial port.
nixnax	174:e5a3f16421a5	650	/// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
nixnax	178:3f17aa0ce5ce	651	/// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
nixnax	178:3f17aa0ce5ce	652	/// See http://www.wikihow.com/Enable-IP-Routing.
nixnax	179:ba2b2ddd0da5	653	/// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
nixnax	179:ba2b2ddd0da5	654	/// The netcat UDP receive command on the remote host would be: nc -ul 12345
nixnax	174:e5a3f16421a5	655	void sendUdpData()
nixnax	174:e5a3f16421a5	656	{
nixnax	174:e5a3f16421a5	657	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	179:ba2b2ddd0da5	658	if (ppp.online) {
nixnax	179:ba2b2ddd0da5	659	if (xx.readable()) {
nixnax	179:ba2b2ddd0da5	660	char inchar = xx.getc();
nixnax	179:ba2b2ddd0da5	661	xx.putc( inchar ); // echo the received character on the debug serial port
nixnax	179:ba2b2ddd0da5	662	sendUdp(ip(172,10,10,2), ip(192,168,0,109), 1, 12345, &inchar, 1); // send a 1 byte UDP message to a remote machine at IP 192.168.0.109:12345
nixnax	179:ba2b2ddd0da5	663	}
nixnax	174:e5a3f16421a5	664	}
nixnax	174:e5a3f16421a5	665	#endif
nixnax	174:e5a3f16421a5	666	}
nixnax	174:e5a3f16421a5	667
nixnax	142:54d1543e23e5	668	/// handle a PING ICMP (internet control message protocol) packet
nixnax	142:54d1543e23e5	669	void ICMPpacket() // internet control message protocol
nixnax	142:54d1543e23e5	670	{
nixnax	165:c47826d07e0d	671	struct {
nixnax	165:c47826d07e0d	672	unsigned int all; // length of entire ip packet
nixnax	165:c47826d07e0d	673	unsigned int header; // length of ip header
nixnax	165:c47826d07e0d	674	} ipLength;
nixnax	165:c47826d07e0d	675	struct {
nixnax	165:c47826d07e0d	676	unsigned int all; // length of entire udp packet
nixnax	165:c47826d07e0d	677	unsigned int data; // length of udp data segment
nixnax	165:c47826d07e0d	678	} icmpLength;
nixnax	165:c47826d07e0d	679	ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax	165:c47826d07e0d	680	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	165:c47826d07e0d	681	ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	165:c47826d07e0d	682	icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax	165:c47826d07e0d	683	icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax	142:54d1543e23e5	684	#define ICMP_TYPE_PING_REQUEST 8
nixnax	165:c47826d07e0d	685	if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax	165:c47826d07e0d	686	ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax	147:0f40005cbc5f	687	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	167:ff8a2d8beeb1	688	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	689	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	165:c47826d07e0d	690	int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax	165:c47826d07e0d	691	int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax	142:54d1543e23e5	692	if(1) {
nixnax	142:54d1543e23e5	693	char pbuf[50];
nixnax	142:54d1543e23e5	694	checkPc();
nixnax	142:54d1543e23e5	695	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	696	putsWhileCheckingInput( pbuf );
nixnax	142:54d1543e23e5	697	checkPc();
nixnax	142:54d1543e23e5	698	sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax	142:54d1543e23e5	699	checkPc();
nixnax	142:54d1543e23e5	700	putsWhileCheckingInput( pbuf );
nixnax	142:54d1543e23e5	701	}
nixnax	142:54d1543e23e5	702	#endif
nixnax	147:0f40005cbc5f	703	swapIpAddresses(); // swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	704	IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax	142:54d1543e23e5	705	#define ICMP_TYPE_ECHO_REPLY 0
nixnax	165:c47826d07e0d	706	ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax	165:c47826d07e0d	707	ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax	165:c47826d07e0d	708	unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax	165:c47826d07e0d	709	ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax	142:54d1543e23e5	710
nixnax	165:c47826d07e0d	711	int printSize = icmpLength.data; // exclude size of icmp header
nixnax	142:54d1543e23e5	712	if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax	142:54d1543e23e5	713	if (0) {
nixnax	142:54d1543e23e5	714	for (int i=0; i<printSize; i++) {
nixnax	165:c47826d07e0d	715	char ch = ppp.icmp->data[i];
nixnax	142:54d1543e23e5	716	if (ch>31 && ch<127) {
nixnax	142:54d1543e23e5	717	putcWhileCheckingInput(ch);
nixnax	142:54d1543e23e5	718	} else {
nixnax	142:54d1543e23e5	719	putcWhileCheckingInput('_');
nixnax	142:54d1543e23e5	720	}
nixnax	142:54d1543e23e5	721	}
nixnax	142:54d1543e23e5	722	putcWhileCheckingInput('\n');
nixnax	142:54d1543e23e5	723	}
nixnax	144:01d98cf7738e	724	sendPppFrame(); // reply to the ping
nixnax	142:54d1543e23e5	725	} else {
nixnax	142:54d1543e23e5	726	if (v0) {
nixnax	165:c47826d07e0d	727	debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax	142:54d1543e23e5	728	}
nixnax	142:54d1543e23e5	729	}
nixnax	142:54d1543e23e5	730	}
nixnax	142:54d1543e23e5	731
nixnax	142:54d1543e23e5	732	/// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax	142:54d1543e23e5	733	void IGMPpacket()
nixnax	142:54d1543e23e5	734	{
nixnax	142:54d1543e23e5	735	if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax	142:54d1543e23e5	736	}
nixnax	142:54d1543e23e5	737
nixnax	142:54d1543e23e5	738	/// dump the header of an IP pakcet on the (optional) debug serial port
nixnax	142:54d1543e23e5	739	void dumpHeaderIP (int outGoing)
nixnax	142:54d1543e23e5	740	{
nixnax	142:54d1543e23e5	741	#if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	142:54d1543e23e5	742	checkPc(); // we are expecting the first character of the next packet
nixnax	155:9c6a1d249e26	743	int IPv4Id = __REV16(ppp.ip->identR);
nixnax	152:025c73b6c0a9	744	char pbuf[80]; // local print buffer
nixnax	142:54d1543e23e5	745	int n=0;
nixnax	142:54d1543e23e5	746	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	142:54d1543e23e5	747	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	748	#define DUMP_FULL_IP_ADDRESS_YES
nixnax	142:54d1543e23e5	749	#ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax	167:ff8a2d8beeb1	750	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	751	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	142:54d1543e23e5	752	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	753	#endif
nixnax	142:54d1543e23e5	754	putsWhileCheckingInput( pbuf );
nixnax	142:54d1543e23e5	755	#ifndef TCP_HEADER_DUMP_YES
nixnax	160:bd701ad564cb	756	putsWhileCheckingInput('\x1b[30m\n'); // if there's no TCP header dump we terminate the line with \n and VT100 code for black
nixnax	142:54d1543e23e5	757	#endif
nixnax	142:54d1543e23e5	758	#endif
nixnax	142:54d1543e23e5	759	}
nixnax	142:54d1543e23e5	760
nixnax	142:54d1543e23e5	761	/// dump a TCP header on the optional debug serial port
nixnax	142:54d1543e23e5	762	void dumpHeaderTCP(int outGoing)
nixnax	142:54d1543e23e5	763	{
nixnax	142:54d1543e23e5	764	#if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	155:9c6a1d249e26	765	char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax	142:54d1543e23e5	766	#define PRINT_ALL_TCP_FLAGS_YES
nixnax	142:54d1543e23e5	767	#ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax	155:9c6a1d249e26	768	memset(flagString,'.', 8); // fill string with "........"
nixnax	156:163c23249731	769	if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax	156:163c23249731	770	if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax	156:163c23249731	771	if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax	156:163c23249731	772	if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax	156:163c23249731	773	if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax	156:163c23249731	774	if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax	156:163c23249731	775	if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax	156:163c23249731	776	if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax	155:9c6a1d249e26	777	flagString[8]=0; // null terminate string
nixnax	142:54d1543e23e5	778	#else
nixnax	156:163c23249731	779	if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax	156:163c23249731	780	if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax	156:163c23249731	781	if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax	156:163c23249731	782	if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax	156:163c23249731	783	if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax	155:9c6a1d249e26	784	flagString[1]=0; // null terminate string
nixnax	142:54d1543e23e5	785	#endif
nixnax	155:9c6a1d249e26	786	putsWhileCheckingInput( flagString );
nixnax	142:54d1543e23e5	787	#define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	142:54d1543e23e5	788	#ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	142:54d1543e23e5	789	putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax	160:bd701ad564cb	790	#else
nixnax	160:bd701ad564cb	791	putsWhileCheckingInput("\x1b[30m"); // write a black color after every packet
nixnax	142:54d1543e23e5	792	#endif
nixnax	156:163c23249731	793	if( outGoing && ppp.tcp->flag.fin ) { // ACK/FIN - if this is an outgoing FIN it's the end of a tcp conversation
nixnax	160:bd701ad564cb	794	putcWhileCheckingInput('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax	142:54d1543e23e5	795	}
nixnax	142:54d1543e23e5	796	#endif
nixnax	142:54d1543e23e5	797	}
nixnax	142:54d1543e23e5	798
nixnax	143:c5019f856a56	799	/// Encode a buffer in base-64
nixnax	184:4133f557d4d4	800	const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax	142:54d1543e23e5	801	void enc64(char * in, char * out, int len)
nixnax	142:54d1543e23e5	802	{
nixnax	142:54d1543e23e5	803	int i,j,a,b,c;
nixnax	142:54d1543e23e5	804	i=0;
nixnax	142:54d1543e23e5	805	j=0;
nixnax	142:54d1543e23e5	806	while(1) {
nixnax	142:54d1543e23e5	807	if (i<len) {
nixnax	142:54d1543e23e5	808	a = in[i++];
nixnax	142:54d1543e23e5	809	out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax	142:54d1543e23e5	810	} else break;
nixnax	142:54d1543e23e5	811	if (i<len) {
nixnax	142:54d1543e23e5	812	b = in[i++];
nixnax	142:54d1543e23e5	813	out[j++] = lut[ ( (a << 4) & 0x30) \| ( (b >> 4) & 0x0f) ];
nixnax	142:54d1543e23e5	814	out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax	142:54d1543e23e5	815	} else out[j++] = '=';
nixnax	142:54d1543e23e5	816	if (i<len) {
nixnax	142:54d1543e23e5	817	c = in[i++];
nixnax	142:54d1543e23e5	818	j--;
nixnax	142:54d1543e23e5	819	out[j++] = lut[ ( (b << 2) & 0x3c) \| ( (c >> 6) & 0x03) ];
nixnax	142:54d1543e23e5	820	out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax	142:54d1543e23e5	821	} else out[j++] = '=';
nixnax	142:54d1543e23e5	822	}
nixnax	142:54d1543e23e5	823	out[j]=0;
nixnax	142:54d1543e23e5	824	}
nixnax	142:54d1543e23e5	825
nixnax	160:bd701ad564cb	826	/// Handle a request for an http websocket.
nixnax	160:bd701ad564cb	827	/// 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	828	int webSocketHandler(char * dataStart)
nixnax	142:54d1543e23e5	829	{
nixnax	142:54d1543e23e5	830	int n=0; // byte counter
nixnax	184:4133f557d4d4	831	char * key = strstr(dataStart, "Sec-WebSocket-Key:"); // search for the key in the payload
nixnax	142:54d1543e23e5	832	if (key != NULL) {
nixnax	184:4133f557d4d4	833	key = key + 18; // skip over the key ident string "Sec-WebSocket-Key:"
nixnax	142:54d1543e23e5	834	if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax	184:4133f557d4d4	835	while ( strchr(lut, *key) == NULL) key++; // skip non-valid base-64 characters (whitespace)
nixnax	184:4133f557d4d4	836	char challenge [80];
nixnax	184:4133f557d4d4	837	int i=0;
nixnax	184:4133f557d4d4	838	char * copyTo = challenge;
nixnax	184:4133f557d4d4	839	while (strchr(lut, *key) != NULL) { // copy while we see valid base-64 characters
nixnax	184:4133f557d4d4	840	if (i++ >40) break; // prevent buffer overflow
nixnax	184:4133f557d4d4	841	copyTo++ = key++; // copy next valid base-64 character
nixnax	184:4133f557d4d4	842	}
nixnax	184:4133f557d4d4	843	strcpy(copyTo,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // append websocket gui code
nixnax	184:4133f557d4d4	844	if (0) debugPrintf("Challenge is %s\n", challenge); // the string we hash for the challenge
nixnax	142:54d1543e23e5	845	char shaOutput [20]; // sha1 output
nixnax	184:4133f557d4d4	846	sha1( shaOutput, challenge, strlen(challenge)); // hash the challenge
nixnax	142:54d1543e23e5	847	char encOut[50];
nixnax	184:4133f557d4d4	848	enc64( shaOutput, encOut, 20); // base-64 encode
nixnax	142:54d1543e23e5	849	char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax	142:54d1543e23e5	850	char * version = challenge;
nixnax	184:4133f557d4d4	851	strncpy(version, versionstring,70); // copy their version string
nixnax	142:54d1543e23e5	852	*strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax	142:54d1543e23e5	853	memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax	142:54d1543e23e5	854	n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax	142:54d1543e23e5	855	n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax	142:54d1543e23e5	856	n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax	142:54d1543e23e5	857	n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax	142:54d1543e23e5	858	n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax	142:54d1543e23e5	859	n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax	142:54d1543e23e5	860	n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax	142:54d1543e23e5	861	}
nixnax	142:54d1543e23e5	862	return n; // this response should satisfy a web browser's websocket protocol request
nixnax	142:54d1543e23e5	863	}
nixnax	142:54d1543e23e5	864
nixnax	142:54d1543e23e5	865	#define TCP_FLAG_ACK (1<<4)
nixnax	142:54d1543e23e5	866	#define TCP_FLAG_SYN (1<<1)
nixnax	142:54d1543e23e5	867	#define TCP_FLAG_PSH (1<<3)
nixnax	142:54d1543e23e5	868	#define TCP_FLAG_RST (1<<2)
nixnax	142:54d1543e23e5	869	#define TCP_FLAG_FIN (1<<0)
nixnax	142:54d1543e23e5	870
nixnax	142:54d1543e23e5	871	/// respond to an HTTP request
nixnax	185:4cd8f91e9d49	872	int httpResponse(char * dataStart, int * flags)
nixnax	142:54d1543e23e5	873	{
nixnax	142:54d1543e23e5	874	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	875	n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax	160:bd701ad564cb	876	if (n>0) return n; // if n>0 we already have a response, so return
nixnax	142:54d1543e23e5	877
nixnax	142:54d1543e23e5	878	int nHeader; // byte size of HTTP header
nixnax	142:54d1543e23e5	879	int contentLengthStart; // index where HTML starts
nixnax	142:54d1543e23e5	880	int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax	185:4cd8f91e9d49	881	*flags = TCP_FLAG_ACK \| TCP_FLAG_FIN; // the default case is that we close the connection
nixnax	142:54d1543e23e5	882
nixnax	142:54d1543e23e5	883	httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax	142:54d1543e23e5	884	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	885	httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	886	httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	887	// for example, you could try this using netcat (nc): echo "GET /x" \| nc 172.10.10.2
nixnax	142:54d1543e23e5	888	if( (httpGetRoot==0) \|\| (httpGetx==0) ) {
nixnax	142:54d1543e23e5	889	n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax	142:54d1543e23e5	890	} else {
nixnax	142:54d1543e23e5	891	n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax	142:54d1543e23e5	892	}
nixnax	142:54d1543e23e5	893	n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax	142:54d1543e23e5	894	contentLengthStart = n; // remember where Content-Length is in buffer
nixnax	142:54d1543e23e5	895	n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax	142:54d1543e23e5	896	n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax	142:54d1543e23e5	897	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	898	nHeader=n; // size of HTTP header
nixnax	185:4cd8f91e9d49	899
nixnax	142:54d1543e23e5	900	if( httpGetRoot == 0 ) {
nixnax	142:54d1543e23e5	901	// this is where we insert our web page into the buffer
nixnax	142:54d1543e23e5	902	memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax	142:54d1543e23e5	903	n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax	185:4cd8f91e9d49	904
nixnax	142:54d1543e23e5	905	} else if ( (httpGet5 == 'w') && (httpGet6 == 's') ) { // "ws" is a special page for websocket demo
nixnax	142:54d1543e23e5	906	memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax	142:54d1543e23e5	907	n = n + sizeof(webSocketPage)-1; // one less than size
nixnax	185:4cd8f91e9d49	908	*flags = TCP_FLAG_ACK \| TCP_FLAG_PSH; // for a websocket page we do NOT close the connection
nixnax	142:54d1543e23e5	909	} else {
nixnax	142:54d1543e23e5	910	if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax	142:54d1543e23e5	911	#define W3C_COMPLIANT_RESPONSE_NO
nixnax	142:54d1543e23e5	912	// change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax	142:54d1543e23e5	913	#ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax	142:54d1543e23e5	914	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax	146:a45f49a2b29c	915	n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax	142:54d1543e23e5	916	#else
nixnax	142:54d1543e23e5	917	if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax	167:ff8a2d8beeb1	918	n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax	142:54d1543e23e5	919	}
nixnax	142:54d1543e23e5	920	// /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax	146:a45f49a2b29c	921	n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax	142:54d1543e23e5	922	#endif
nixnax	142:54d1543e23e5	923	} else {
nixnax	142:54d1543e23e5	924	// all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax	142:54d1543e23e5	925	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax	142:54d1543e23e5	926	n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax	142:54d1543e23e5	927	}
nixnax	142:54d1543e23e5	928	}
nixnax	142:54d1543e23e5	929	#define CONTENTLENGTHSIZE 5
nixnax	142:54d1543e23e5	930	char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax	142:54d1543e23e5	931	snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax	142:54d1543e23e5	932	memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax	142:54d1543e23e5	933	return n; // total byte size of our response
nixnax	142:54d1543e23e5	934	}
nixnax	142:54d1543e23e5	935
nixnax	160:bd701ad564cb	936	/// Handle TCP data that is not an HTTP GET.
nixnax	160:bd701ad564cb	937	/// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax	160:bd701ad564cb	938	/// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax	142:54d1543e23e5	939	int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax	142:54d1543e23e5	940	{
nixnax	142:54d1543e23e5	941	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	942	if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax	160:bd701ad564cb	943	char mask [4];
nixnax	160:bd701ad564cb	944	memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax	160:bd701ad564cb	945	int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax	160:bd701ad564cb	946	if((dataStart[1]&0x80)==0x80) // test if the mask bit is set, which means all data is xor'ed with the mask
nixnax	160:bd701ad564cb	947	for (int i=0; i<websocketMessageSize; i++) dataStart[i+6]^= mask[i%4]; // unmask each byte with one of the mask bytes
nixnax	160:bd701ad564cb	948	dataStart[1] = len-2; // add four extra bytes to the message length because we don't use mask bytes for the send
nixnax	160:bd701ad564cb	949	memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax	160:bd701ad564cb	950	n = len; // our response size remains exactly the same length as what we received
nixnax	142:54d1543e23e5	951	} else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax	142:54d1543e23e5	952	n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax	142:54d1543e23e5	953	dataStart[1]=0; // we don't have mask bytes on
nixnax	160:bd701ad564cb	954	} else {
nixnax	184:4133f557d4d4	955	if ( len > 1 ) { // we assume a length of 1 is a keep-alive or push packet
nixnax	184:4133f557d4d4	956	if (v1) putsWhileCheckingInput("TCP data received\n"); // all other tcp push packets
nixnax	184:4133f557d4d4	957	}
nixnax	163:d1b4328e9f08	958	}
nixnax	142:54d1543e23e5	959	return n; // total byte size of our response
nixnax	142:54d1543e23e5	960	}
nixnax	142:54d1543e23e5	961
nixnax	173:6774a0c851c4	962	/// dump the TCP data to the debug serial port
nixnax	173:6774a0c851c4	963	void dumpDataTCP(int outGoing)
nixnax	173:6774a0c851c4	964	{
nixnax	173:6774a0c851c4	965	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	173:6774a0c851c4	966	if (v2) {
nixnax	173:6774a0c851c4	967	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	173:6774a0c851c4	968	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	969	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax	173:6774a0c851c4	970	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	173:6774a0c851c4	971	ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
nixnax	173:6774a0c851c4	972	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	173:6774a0c851c4	973	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	173:6774a0c851c4	974	char pbuf[80]; // local print buffer
nixnax	173:6774a0c851c4	975	int n=0;
nixnax	173:6774a0c851c4	976	checkPc();
nixnax	173:6774a0c851c4	977	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	173:6774a0c851c4	978	checkPc();
nixnax	173:6774a0c851c4	979	n=n+sprintf(pbuf+n, "IP:%d ipHeader:%d tcpHeader:%d tcpData:%d\n", packetLengthIp, headerSizeIp, headerSizeTcp, tcpDataSize); // 1 for more verbose
nixnax	184:4133f557d4d4	980	if (n>70) putsWhileCheckingInput("n>pbuf overflow in dumpDataTCP()\n");
nixnax	173:6774a0c851c4	981	checkPc();
nixnax	173:6774a0c851c4	982	putsWhileCheckingInput( pbuf );
nixnax	173:6774a0c851c4	983	if (tcpDataSize > 0) {
nixnax	173:6774a0c851c4	984	ppp.tcpData[tcpDataSize]=0; // insert a null after the data so debug printf stops printing after the data
nixnax	173:6774a0c851c4	985	putsWhileCheckingInput( ppp.tcpData ); // print the tcp payload data
nixnax	173:6774a0c851c4	986	putsWhileCheckingInput("\n");
nixnax	173:6774a0c851c4	987	}
nixnax	173:6774a0c851c4	988	putsWhileCheckingInput( "\x1b[30m" ); // VT100 color code, print black
nixnax	173:6774a0c851c4	989	}
nixnax	173:6774a0c851c4	990	#endif
nixnax	173:6774a0c851c4	991	}
nixnax	173:6774a0c851c4	992
nixnax	142:54d1543e23e5	993	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	994	/// 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	995	void tcpHandler()
nixnax	142:54d1543e23e5	996	{
nixnax	154:18b2bd92f557	997	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	154:18b2bd92f557	998	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	999	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate TCP header start
nixnax	154:18b2bd92f557	1000	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	154:18b2bd92f557	1001	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	173:6774a0c851c4	1002	char * tcpDataIn = ppp.tcpStart + headerSizeTcp; // start of data TCP data after TCP header
nixnax	154:18b2bd92f557	1003	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	154:18b2bd92f557	1004
nixnax	154:18b2bd92f557	1005	unsigned int seq_in = __REV(ppp.tcp->seqTcpR);
nixnax	154:18b2bd92f557	1006	unsigned int ack_in = __REV(ppp.tcp->ackTcpR);
nixnax	142:54d1543e23e5	1007	unsigned int ack_out = seq_in + tcpDataSize;
nixnax	142:54d1543e23e5	1008	unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax	142:54d1543e23e5	1009
nixnax	142:54d1543e23e5	1010	// first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax	173:6774a0c851c4	1011	headerSizeIp=20;
nixnax	173:6774a0c851c4	1012	ppp.ip->headerLength = headerSizeIp/4; // ip header is 20 bytes long
nixnax	173:6774a0c851c4	1013	ppp.ip->lengthR = __REV(40); // 20 ip header + 20 tcp header
nixnax	173:6774a0c851c4	1014	//tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax	154:18b2bd92f557	1015	headerSizeTcp = 20; // shorten outgoing TCP header size 20 bytes
nixnax	173:6774a0c851c4	1016	ppp.tcpStart = ppp.ipStart + headerSizeIp; // recalc TCP header start
nixnax	154:18b2bd92f557	1017	ppp.tcp->offset = (headerSizeTcp/4);
nixnax	173:6774a0c851c4	1018	char * tcpDataOut = ppp.tcpStart + headerSizeTcp; // start of outgoing data
nixnax	142:54d1543e23e5	1019
nixnax	142:54d1543e23e5	1020	int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax	142:54d1543e23e5	1021	int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax	160:bd701ad564cb	1022
nixnax	185:4cd8f91e9d49	1023	ppp.tcp->windowR = __REV16( 1200 ); // set tcp window size to 1200 bytes
nixnax	142:54d1543e23e5	1024
nixnax	142:54d1543e23e5	1025	// A sparse TCP flag interpreter that implements stateless TCP connections
nixnax	142:54d1543e23e5	1026
nixnax	156:163c23249731	1027	switch ( ppp.tcp->flag.All ) {
nixnax	142:54d1543e23e5	1028	case TCP_FLAG_SYN:
nixnax	142:54d1543e23e5	1029	flagsOut = TCP_FLAG_SYN \| TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax	142:54d1543e23e5	1030	seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax	142:54d1543e23e5	1031	ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1032	break;
nixnax	184:4133f557d4d4	1033	case TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1034	case TCP_FLAG_ACK \| TCP_FLAG_PSH:
nixnax	184:4133f557d4d4	1035	if ( (ppp.tcp->flag.All == TCP_FLAG_ACK) && (tcpDataSize == 0)) return; // handle zero-size ack messages by ignoring them
nixnax	142:54d1543e23e5	1036	if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax	179:ba2b2ddd0da5	1037	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // we have data, set the PSH flag
nixnax	185:4cd8f91e9d49	1038	dataLen = httpResponse(tcpDataOut, &flagsOut); // send an http response
nixnax	142:54d1543e23e5	1039	} else {
nixnax	158:841592aed956	1040	dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax	179:ba2b2ddd0da5	1041	if (dataLen > 0) flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // if we have any data set the PSH flag
nixnax	142:54d1543e23e5	1042	}
nixnax	142:54d1543e23e5	1043	break;
nixnax	142:54d1543e23e5	1044	case TCP_FLAG_FIN:
nixnax	142:54d1543e23e5	1045	case TCP_FLAG_FIN \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1046	case TCP_FLAG_FIN \| TCP_FLAG_PSH \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1047	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax	142:54d1543e23e5	1048	ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1049	break;
nixnax	142:54d1543e23e5	1050	default:
nixnax	179:ba2b2ddd0da5	1051	return; // ignore all other packets
nixnax	142:54d1543e23e5	1052	} // switch
nixnax	142:54d1543e23e5	1053
nixnax	142:54d1543e23e5	1054	// The TCP flag handling is now done
nixnax	142:54d1543e23e5	1055	// first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax	147:0f40005cbc5f	1056	swapIpAddresses(); // swap IP source and destination addresses
nixnax	149:969d98f6fb88	1057	swapIpPorts(); // swap IP source and destination ports
nixnax	142:54d1543e23e5	1058
nixnax	158:841592aed956	1059	ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	158:841592aed956	1060	ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	160:bd701ad564cb	1061
nixnax	156:163c23249731	1062	ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax	142:54d1543e23e5	1063
nixnax	159:4d1bf96a59cd	1064	// recalculate all the header sizes
nixnax	154:18b2bd92f557	1065	tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax	154:18b2bd92f557	1066	int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax	159:4d1bf96a59cd	1067	ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax	142:54d1543e23e5	1068	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	1069
nixnax	142:54d1543e23e5	1070	// the header is all set up, now do the IP and TCP checksums
nixnax	146:a45f49a2b29c	1071	IpHeaderCheckSum(); // calculate new IP header checksum
nixnax	170:3d3b2126181c	1072	checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax	159:4d1bf96a59cd	1073	ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	161:d59f778bc8ab	1074	unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax	159:4d1bf96a59cd	1075	ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	160:bd701ad564cb	1076
nixnax	170:3d3b2126181c	1077	dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax	170:3d3b2126181c	1078	dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax	173:6774a0c851c4	1079	dumpDataTCP(1); // dump outgoing TCP data before sending the frame
nixnax	182:f039ec218c9f	1080	if (0) wait_ms(45); // 45 ms delay before sending frame - a typical internet delay time
nixnax	144:01d98cf7738e	1081	sendPppFrame(); // All preparation complete - send the TCP response
nixnax	142:54d1543e23e5	1082	if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
nixnax	142:54d1543e23e5	1083	memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax	142:54d1543e23e5	1084	}
nixnax	142:54d1543e23e5	1085
nixnax	142:54d1543e23e5	1086	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1087	void TCPpacket()
nixnax	142:54d1543e23e5	1088	{
nixnax	173:6774a0c851c4	1089	dumpHeaderIP(0); // dump incoming packet IP header
nixnax	173:6774a0c851c4	1090	dumpHeaderTCP(0); // dump incoming packet TCP header
nixnax	173:6774a0c851c4	1091	dumpDataTCP(0); // dump incoming packet data
nixnax	142:54d1543e23e5	1092	tcpHandler();
nixnax	142:54d1543e23e5	1093	}
nixnax	142:54d1543e23e5	1094
nixnax	142:54d1543e23e5	1095	/// handle the remaining IP protocols by ignoring them
nixnax	142:54d1543e23e5	1096	void otherProtocol()
nixnax	142:54d1543e23e5	1097	{
nixnax	142:54d1543e23e5	1098	debugPrintf("Other IP protocol");
nixnax	142:54d1543e23e5	1099	}
nixnax	142:54d1543e23e5	1100
nixnax	142:54d1543e23e5	1101	/// process an incoming IP packet
nixnax	142:54d1543e23e5	1102	void IPframe()
nixnax	142:54d1543e23e5	1103	{
nixnax	167:ff8a2d8beeb1	1104	int protocol = ppp.ip->protocol;
nixnax	142:54d1543e23e5	1105	switch (protocol) {
nixnax	142:54d1543e23e5	1106	case 1:
nixnax	142:54d1543e23e5	1107	ICMPpacket();
nixnax	142:54d1543e23e5	1108	break;
nixnax	142:54d1543e23e5	1109	case 2:
nixnax	142:54d1543e23e5	1110	IGMPpacket();
nixnax	142:54d1543e23e5	1111	break;
nixnax	142:54d1543e23e5	1112	case 17:
nixnax	142:54d1543e23e5	1113	UDPpacket();
nixnax	142:54d1543e23e5	1114	break;
nixnax	142:54d1543e23e5	1115	case 6:
nixnax	142:54d1543e23e5	1116	TCPpacket();
nixnax	142:54d1543e23e5	1117	break;
nixnax	142:54d1543e23e5	1118	default:
nixnax	142:54d1543e23e5	1119	otherProtocol();
nixnax	142:54d1543e23e5	1120	}
nixnax	142:54d1543e23e5	1121	}
nixnax	142:54d1543e23e5	1122
nixnax	142:54d1543e23e5	1123	/// respond to LCP (line configuration protocol) configuration request) by allowing no options
nixnax	142:54d1543e23e5	1124	void LCPconfReq()
nixnax	142:54d1543e23e5	1125	{
nixnax	142:54d1543e23e5	1126	debugPrintf("LCP Config ");
nixnax	175:b4e6f8a6fe00	1127	if ( ppp.lcp->lengthR != __REV16(4) ) {
nixnax	175:b4e6f8a6fe00	1128	ppp.lcp->code=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax	142:54d1543e23e5	1129	debugPrintf("Reject\n");
nixnax	144:01d98cf7738e	1130	sendPppFrame();
nixnax	142:54d1543e23e5	1131	} else {
nixnax	175:b4e6f8a6fe00	1132	ppp.lcp->code=2; // ack zero conf
nixnax	142:54d1543e23e5	1133	debugPrintf("Ack\n");
nixnax	144:01d98cf7738e	1134	sendPppFrame();
nixnax	142:54d1543e23e5	1135	debugPrintf("LCP Ask\n");
nixnax	175:b4e6f8a6fe00	1136	ppp.lcp->code=1; // request no options
nixnax	144:01d98cf7738e	1137	sendPppFrame();
nixnax	142:54d1543e23e5	1138	}
nixnax	142:54d1543e23e5	1139	}
nixnax	142:54d1543e23e5	1140
nixnax	142:54d1543e23e5	1141	/// handle LCP acknowledge packets by ignoring them
nixnax	142:54d1543e23e5	1142	void LCPconfAck()
nixnax	142:54d1543e23e5	1143	{
nixnax	142:54d1543e23e5	1144	debugPrintf("LCP Ack\n");
nixnax	142:54d1543e23e5	1145	}
nixnax	142:54d1543e23e5	1146
nixnax	143:c5019f856a56	1147	/// handle LCP end (disconnect) packets by acknowledging them and by setting ppp.online to false
nixnax	142:54d1543e23e5	1148	void LCPend()
nixnax	142:54d1543e23e5	1149	{
nixnax	175:b4e6f8a6fe00	1150	ppp.lcp->code=6; // end
nixnax	144:01d98cf7738e	1151	sendPppFrame(); // acknowledge
nixnax	142:54d1543e23e5	1152	ppp.online=0; // start hunting for connect string again
nixnax	142:54d1543e23e5	1153	pppInitStruct(); // flush the receive buffer
nixnax	143:c5019f856a56	1154	debugPrintf("LCP End (Disconnect from host)\n");
nixnax	142:54d1543e23e5	1155	}
nixnax	142:54d1543e23e5	1156
nixnax	142:54d1543e23e5	1157	/// respond to other LCP requests by ignoring them
nixnax	142:54d1543e23e5	1158	void LCPother()
nixnax	142:54d1543e23e5	1159	{
nixnax	142:54d1543e23e5	1160	debugPrintf("LCP Other\n");
nixnax	142:54d1543e23e5	1161	dumpPPPFrame();
nixnax	142:54d1543e23e5	1162	}
nixnax	142:54d1543e23e5	1163
nixnax	142:54d1543e23e5	1164	/// process incoming LCP packets
nixnax	142:54d1543e23e5	1165	void LCPframe()
nixnax	142:54d1543e23e5	1166	{
nixnax	175:b4e6f8a6fe00	1167	int code = ppp.lcp->code;
nixnax	142:54d1543e23e5	1168	switch (code) {
nixnax	142:54d1543e23e5	1169	case 1:
nixnax	142:54d1543e23e5	1170	LCPconfReq();
nixnax	142:54d1543e23e5	1171	break; // config request
nixnax	142:54d1543e23e5	1172	case 2:
nixnax	142:54d1543e23e5	1173	LCPconfAck();
nixnax	142:54d1543e23e5	1174	break; // config ack
nixnax	142:54d1543e23e5	1175	case 5:
nixnax	142:54d1543e23e5	1176	LCPend();
nixnax	142:54d1543e23e5	1177	break; // end connection
nixnax	142:54d1543e23e5	1178	default:
nixnax	142:54d1543e23e5	1179	LCPother();
nixnax	142:54d1543e23e5	1180	}
nixnax	142:54d1543e23e5	1181	}
nixnax	142:54d1543e23e5	1182
nixnax	142:54d1543e23e5	1183	/// discard packets that are not IP, IPCP, or LCP
nixnax	142:54d1543e23e5	1184	void discardedFrame()
nixnax	142:54d1543e23e5	1185	{
nixnax	142:54d1543e23e5	1186	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	1187	}
nixnax	142:54d1543e23e5	1188
nixnax	142:54d1543e23e5	1189	/// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax	142:54d1543e23e5	1190	void determinePacketType()
nixnax	142:54d1543e23e5	1191	{
nixnax	167:ff8a2d8beeb1	1192	if ( ppp.ppp->address != 0xff ) {
nixnax	167:ff8a2d8beeb1	1193	debugPrintf("Unexpected: PPP address != ff\n");
nixnax	142:54d1543e23e5	1194	return;
nixnax	142:54d1543e23e5	1195	}
nixnax	167:ff8a2d8beeb1	1196	if ( ppp.ppp->control != 3 ) {
nixnax	167:ff8a2d8beeb1	1197	debugPrintf("Unexpected: PPP control != 3\n");
nixnax	142:54d1543e23e5	1198	return;
nixnax	142:54d1543e23e5	1199	}
nixnax	167:ff8a2d8beeb1	1200	unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax	167:ff8a2d8beeb1	1201	switch ( protocol ) {
nixnax	167:ff8a2d8beeb1	1202	case 0xc021:
nixnax	142:54d1543e23e5	1203	LCPframe();
nixnax	142:54d1543e23e5	1204	break; // link control
nixnax	167:ff8a2d8beeb1	1205	case 0x8021:
nixnax	142:54d1543e23e5	1206	IPCPframe();
nixnax	142:54d1543e23e5	1207	break; // IP control
nixnax	167:ff8a2d8beeb1	1208	case 0x0021:
nixnax	142:54d1543e23e5	1209	IPframe();
nixnax	142:54d1543e23e5	1210	break; // IP itself
nixnax	142:54d1543e23e5	1211	default:
nixnax	142:54d1543e23e5	1212	discardedFrame();
nixnax	142:54d1543e23e5	1213	}
nixnax	142:54d1543e23e5	1214	}
nixnax	142:54d1543e23e5	1215
nixnax	146:a45f49a2b29c	1216	/// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax	146:a45f49a2b29c	1217	void sniff()
nixnax	146:a45f49a2b29c	1218	{
nixnax	146:a45f49a2b29c	1219	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	1220	}
nixnax	146:a45f49a2b29c	1221
nixnax	142:54d1543e23e5	1222	/// scan the PPP serial input stream for frame start markers
nixnax	143:c5019f856a56	1223	void waitForPppFrame()
nixnax	142:54d1543e23e5	1224	{
nixnax	142:54d1543e23e5	1225	while(1) {
nixnax	182:f039ec218c9f	1226	sendUdpData(); // handle received characters from the DEBUG TERMINAL
nixnax	142:54d1543e23e5	1227	if ( ppp.rx.head != ppp.rx.tail ) {
nixnax	142:54d1543e23e5	1228	int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax	142:54d1543e23e5	1229	int rx = pc_getBuf(); // get the character
nixnax	142:54d1543e23e5	1230	if (rx==FRAME_7E) {
nixnax	142:54d1543e23e5	1231	if (ppp.firstFrame) { // is this the start of the first frame start
nixnax	142:54d1543e23e5	1232	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1233	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax	181:bcfe7fe2142d	1234	ppp.firstFrame=0; // clear first frame flag
nixnax	142:54d1543e23e5	1235	} else {
nixnax	142:54d1543e23e5	1236	ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax	142:54d1543e23e5	1237	processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax	142:54d1543e23e5	1238	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1239	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax	142:54d1543e23e5	1240	break;
nixnax	142:54d1543e23e5	1241	}
nixnax	142:54d1543e23e5	1242	}
nixnax	142:54d1543e23e5	1243	}
nixnax	142:54d1543e23e5	1244	}
nixnax	142:54d1543e23e5	1245	}
nixnax	142:54d1543e23e5	1246
nixnax	153:7993def8663f	1247	/// Wait for a dial-up modem connect command ("CLIENT") from the host PC, if found, we set ppp.online to true, which will start the IP packet scanner.
nixnax	153:7993def8663f	1248	// Note: a 0x7E in the input stream (ppp start of frame character) will also set ppp.online to true - see checkPc();
nixnax	153:7993def8663f	1249	void waitForPcConnectString()
nixnax	142:54d1543e23e5	1250	{
nixnax	142:54d1543e23e5	1251	while(ppp.online == 0) {
nixnax	142:54d1543e23e5	1252	checkPc(); // gather received characters
nixnax	142:54d1543e23e5	1253	// search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax	142:54d1543e23e5	1254	char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax	142:54d1543e23e5	1255	if (found1 != NULL) {
nixnax	142:54d1543e23e5	1256	// respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax	143:c5019f856a56	1257	if (v0) debugPrintf("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax	142:54d1543e23e5	1258	pc.puts("CLIENTSERVER");
nixnax	142:54d1543e23e5	1259	ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax	142:54d1543e23e5	1260	checkPc();
nixnax	142:54d1543e23e5	1261	}
nixnax	142:54d1543e23e5	1262	}
nixnax	142:54d1543e23e5	1263	}
nixnax	142:54d1543e23e5	1264
nixnax	144:01d98cf7738e	1265	/// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax	144:01d98cf7738e	1266	void initializePpp()
nixnax	142:54d1543e23e5	1267	{
nixnax	144:01d98cf7738e	1268	debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax	184:4133f557d4d4	1269	debugPrintf("\x1b[2J\x1b[H\x1b[30m");
nixnax	184:4133f557d4d4	1270	wait_ms(200); // a brief wait so a human can see the reset event
nixnax	184:4133f557d4d4	1271	debugPrintf("mbed PPP-Blinky HTTP & WebSocket server ready :)\n"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
nixnax	184:4133f557d4d4	1272
nixnax	179:ba2b2ddd0da5	1273	pppInitStruct(); // initialize all the variables/properties/buffers
nixnax	179:ba2b2ddd0da5	1274	pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
nixnax	179:ba2b2ddd0da5	1275	pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
nixnax	143:c5019f856a56	1276	}

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Repository details

Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	27 Dec 2016
Imports:	426
Forks:	1
Commits:	276
Dependents:	0
Dependencies:	1
Followers:	22

The code in this repository is MIT licensed.