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@228:7fb878500862, 2018-09-17 (annotated)

Committer:: nixnax
Date:: Mon Sep 17 03:38:27 2018 +0000
Revision:: 228:7fb878500862
Parent:: 227:f87156f9ef11
Child:: 229:a81c37376187

removed LCPConfigurationRequest()

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	201:9fcf92e9f427	12	// Important - ensure that you are using the latest mbed firmware for your specific mbed target board
nixnax	201:9fcf92e9f427	13
nixnax	142:54d1543e23e5	14	// Handy reading material
nixnax	142:54d1543e23e5	15	// https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax	142:54d1543e23e5	16	// https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax	142:54d1543e23e5	17	// http://atari.kensclassics.org/wcomlog.htm
nixnax	142:54d1543e23e5	18
nixnax	142:54d1543e23e5	19	// Handy tools
nixnax	142:54d1543e23e5	20	// https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax	142:54d1543e23e5	21	// https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax	142:54d1543e23e5	22	// http://pingtester.net/ - nice tool for high rate ping testing
nixnax	142:54d1543e23e5	23	// http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE), then custom relected-in=1, reflected-out=1
nixnax	142:54d1543e23e5	24	// https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax	142:54d1543e23e5	25	// https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax	142:54d1543e23e5	26	// Windows Powershell invoke-webrequest command - use it to stress test the webserver like this: while (1){ invoke-webrequest -uri 172.10.10.1/x }
nixnax	142:54d1543e23e5	27
nixnax	142:54d1543e23e5	28	// Connecting PPP-Blinky to Linux
nixnax	142:54d1543e23e5	29	// PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax	142:54d1543e23e5	30	// pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax	142:54d1543e23e5	31	// in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax	142:54d1543e23e5	32	// See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax	142:54d1543e23e5	33
nixnax	142:54d1543e23e5	34	// Special pages when PPP-Blinky is running
nixnax	142:54d1543e23e5	35	// 172.10.10.2 root page
nixnax	182:f039ec218c9f	36	// 172.10.10.2/x returns the number of ppp frames sent - this is handy for testing
nixnax	182:f039ec218c9f	37	// 172.10.10.2/xb also returns number of ppp frames sent, but issues a fast refresh meta command. This allows you to use your browser to benchmark page load speed
nixnax	142:54d1543e23e5	38	// 172.10.10.2/ws a simple WebSocket demo
nixnax	182:f039ec218c9f	39	// http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle, showing cross-domain access
nixnax	207:28cd834b785d	40
nixnax	142:54d1543e23e5	41	// Ok, enough talking, time to check out some code!!
nixnax	142:54d1543e23e5	42
nixnax	142:54d1543e23e5	43	#include "ppp-blinky.h"
nixnax	142:54d1543e23e5	44
nixnax	142:54d1543e23e5	45	// The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax	146:a45f49a2b29c	46	// Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor the debug output.
nixnax	142:54d1543e23e5	47	// Using the second serial port will slow down packet response time
nixnax	142:54d1543e23e5	48	// Note - the LPC11U24 does NOT have a second serial port
nixnax	146:a45f49a2b29c	49
nixnax	183:6d3ba874b267	50	#define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax	142:54d1543e23e5	51
nixnax	142:54d1543e23e5	52	// here we define the OPTIONAL, second debug serial port for various mbed target boards
nixnax	142:54d1543e23e5	53	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	142:54d1543e23e5	54	#if defined(TARGET_LPC1768)
nixnax	179:ba2b2ddd0da5	55	RawSerial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	56	#elif defined(TARGET_NUCLEO_F446RE) \|\| defined(TARGET_NUCLEO_L152RE) \|\| defined(TARGET_NUCLEO_L053R8) \|\| defined(TARGET_NUCLEO_L476RG) \|\| defined(TARGET_NUCLEO_F401RE)
nixnax	179:ba2b2ddd0da5	57	RawSerial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	196:8791e241be80	58	#elif defined(TARGET_NUCLEO_L432KC)
nixnax	196:8791e241be80	59	RawSerial xx(PA_9, PA_10); // Second serial port on NUCLEO-L432KC - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	60	#elif defined(TARGET_LPC11U24)
nixnax	142:54d1543e23e5	61	#error The LPC11U24 does not have a second serial port to use for debugging - change SERIAL_PORT_MONITOR_YES back to SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	62	#elif defined (TARGET_KL46Z) \|\| (TARGET_KL25Z)
nixnax	179:ba2b2ddd0da5	63	RawSerial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax	193:48072570f41d	64	#elif defined(TARGET_KW41Z)
nixnax	194:5b23ebfb3626	65	RawSerial xx(PTC3, PTC2); // Second serial port on FRDM-KW41Z board
nixnax	142:54d1543e23e5	66	#elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax	142:54d1543e23e5	67	// change the next line to YOUR target board's second serial port pin definition if it's not present - and if it works, please send it to me - thanks!!!
nixnax	226:4898247048c7	68	RawSerial xx(p9, p10); // change this to YOUR board's second serial port pin definition - and please send it to me if it works!!!
nixnax	142:54d1543e23e5	69	#else
nixnax	142:54d1543e23e5	70	#error Add your target board's second serial port here if you want to use debugging - or simply change SERIAL_PORT_MONITOR_YES to SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	71	#endif
nixnax	179:ba2b2ddd0da5	72	#define debugPrintf(x...) xx.printf (x) /* if we have a serial port we can print debug messages */
nixnax	142:54d1543e23e5	73	#define debugPutc(x...) xx.putc(x)
nixnax	221:1d7c32d8256b	74	#define debugPuts(x...) xx.puts(x)
nixnax	142:54d1543e23e5	75	#define debugBaudRate(x...) xx.baud(x)
nixnax	142:54d1543e23e5	76	#else
nixnax	142:54d1543e23e5	77	// if we don't have a debug port the debug print functions do nothing
nixnax	142:54d1543e23e5	78	#define debugPrintf(x...) {}
nixnax	142:54d1543e23e5	79	#define debugPutc(x...) {}
nixnax	221:1d7c32d8256b	80	#define debugPuts(x...) {}
nixnax	142:54d1543e23e5	81	#define debugBaudRate(x...) {}
nixnax	142:54d1543e23e5	82	#endif
nixnax	142:54d1543e23e5	83
nixnax	142:54d1543e23e5	84	// verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax	182:f039ec218c9f	85	#define v0 1
nixnax	142:54d1543e23e5	86	#define v1 0
nixnax	142:54d1543e23e5	87	#define v2 0
nixnax	182:f039ec218c9f	88	#define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax	182:f039ec218c9f	89	#define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax	226:4898247048c7	90	#define DUMP_RECEIVED_PPP_FRAMES_NO /* YES to dump received PPP frames */
nixnax	142:54d1543e23e5	91
nixnax	226:4898247048c7	92	// below is the webpage we serve when we get an HTTP request to root (/)
nixnax	226:4898247048c7	93	// keep size under ~1400 bytes to fit into a single PPP packet
nixnax	142:54d1543e23e5	94
nixnax	142:54d1543e23e5	95	const static char rootWebPage[] = "\
nixnax	142:54d1543e23e5	96	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	97	<html>\
nixnax	142:54d1543e23e5	98	<head>\
nixnax	146:a45f49a2b29c	99	<title>mbed PPP-Blinky</title>\r\n\
nixnax	226:4898247048c7	100	<style>\
nixnax	226:4898247048c7	101	body {font-family:sans-serif; font-size:150%; text-align:center; color:#807070;}\
nixnax	226:4898247048c7	102	</style>\
nixnax	142:54d1543e23e5	103	</head>\
nixnax	226:4898247048c7	104	<body>\
nixnax	142:54d1543e23e5	105	<h1>mbed PPP-Blinky Up and Running</h1>\
nixnax	142:54d1543e23e5	106	<h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax	210:a2a651249a9a	107	<h1><a href=\"/w\">WebSocket Test</a></h1>\
nixnax	142:54d1543e23e5	108	<h1><a href=\"/x\">Benchmark 1</a></h1>\
nixnax	142:54d1543e23e5	109	<h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax	225:4c9994e3becb	110	<h1><a href=\"http://jsfiddle.net/d26cyuh2/112/embedded/result\">JSFiddle Demo</a></h1>\
nixnax	142:54d1543e23e5	111	</body>\
nixnax	226:4898247048c7	112	</html>\r\n"; // size = 483 bytes + 1 null byte = 484 bytes
nixnax	142:54d1543e23e5	113
nixnax	167:ff8a2d8beeb1	114	// this is a websocket demo html page we serve when GET /ws is requested
nixnax	226:4898247048c7	115	// it contains some javascript to handle the websocket activities
nixnax	142:54d1543e23e5	116	const static char webSocketPage[] = "\
nixnax	142:54d1543e23e5	117	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	118	<html>\
nixnax	142:54d1543e23e5	119	<head>\
nixnax	226:4898247048c7	120	<title>mbed PPP-Blinky WebSocket</title>\
nixnax	142:54d1543e23e5	121	<script>\
nixnax	142:54d1543e23e5	122	window.onload=function(){\
nixnax	142:54d1543e23e5	123	var url=\"ws://172.10.10.2\";\
nixnax	142:54d1543e23e5	124	var sts=document.getElementById(\"sts\");\
nixnax	142:54d1543e23e5	125	var btn=document.getElementById(\"btn\");\
nixnax	142:54d1543e23e5	126	var ctr=0;\
nixnax	142:54d1543e23e5	127	function show(text){sts.textContent=text;}\
nixnax	142:54d1543e23e5	128	btn.onclick=function(){\
nixnax	142:54d1543e23e5	129	if(btn.textContent==\"Connect\"){\
nixnax	142:54d1543e23e5	130	x=new WebSocket(url);\
nixnax	142:54d1543e23e5	131	x.onopen=function(){\
nixnax	226:4898247048c7	132	show(\"Connected to PPP-Blinky WebSocket service at: \"+url);\
nixnax	142:54d1543e23e5	133	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	134	};\
nixnax	226:4898247048c7	135	x.onclose=function(){show(\"WebSocket closed\");};\
nixnax	226:4898247048c7	136	x.onmessage=function(msg){show(\"PPP-Blinky WebSocket service responded with: \\\"\"+msg.data+\"\\\"\");};\
nixnax	142:54d1543e23e5	137	} else {\
nixnax	142:54d1543e23e5	138	x.send(ctr);\
nixnax	142:54d1543e23e5	139	ctr=ctr+1;\
nixnax	142:54d1543e23e5	140	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	141	}\
nixnax	142:54d1543e23e5	142	};\
nixnax	142:54d1543e23e5	143	};\
nixnax	142:54d1543e23e5	144	</script>\
nixnax	226:4898247048c7	145	<style>\
nixnax	226:4898247048c7	146	body {font-family:sans-serif; font-size:150%; text-align:center; color:#807070;}\
nixnax	226:4898247048c7	147	button {font-size:150%; background-color:#7eeeee; border-radius:15px; border:none; margin-top:20px; }\
nixnax	226:4898247048c7	148	</style>\
nixnax	226:4898247048c7	149	<body>\
nixnax	226:4898247048c7	150	<h1>mbed PPP-Blinky WebSocket Test</h1>\
nixnax	226:4898247048c7	151	<h1><div id=\"sts\">Idle</div><h1>\
nixnax	226:4898247048c7	152	<button id=\"btn\">Connect</button>\
nixnax	142:54d1543e23e5	153	</body>\
nixnax	226:4898247048c7	154	</html>"; // size = 1037 bytes + 1 null byte = 1038 bytes
nixnax	142:54d1543e23e5	155
nixnax	142:54d1543e23e5	156	// 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	157	// On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax	142:54d1543e23e5	158	// The modem baud rate should be set to 115200 baud
nixnax	142:54d1543e23e5	159	// See instructions at the top.
nixnax	142:54d1543e23e5	160	// 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	161	RawSerial pc (USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax	142:54d1543e23e5	162
nixnax	142:54d1543e23e5	163	DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax	142:54d1543e23e5	164
nixnax	142:54d1543e23e5	165	// the standard hdlc frame start/end character. It's the tilde character "~"
nixnax	142:54d1543e23e5	166	#define FRAME_7E (0x7e)
nixnax	142:54d1543e23e5	167
nixnax	142:54d1543e23e5	168	pppType ppp; // our global - definitely not thread safe
nixnax	142:54d1543e23e5	169
nixnax	142:54d1543e23e5	170	/// Initialize the ppp structure and clear the receive buffer
nixnax	142:54d1543e23e5	171	void pppInitStruct()
nixnax	142:54d1543e23e5	172	{
nixnax	223:917b554cb8a5	173	memset( (void *)ppp.rx.buf, 0, RXBUFLEN+1); // one extra byte at the end which always remains zero so strstr() cannot exceed the buffer
nixnax	142:54d1543e23e5	174	ppp.online=0;
nixnax	142:54d1543e23e5	175	ppp.rx.tail=0;
nixnax	142:54d1543e23e5	176	ppp.rx.rtail=0;
nixnax	142:54d1543e23e5	177	ppp.rx.head=0;
nixnax	142:54d1543e23e5	178	ppp.rx.buflevel=0;
nixnax	209:aa514cd631ee	179	ppp.rx.maxbuflevel=0;
nixnax	221:1d7c32d8256b	180	ppp.rx.bufferfull=0;
nixnax	142:54d1543e23e5	181	ppp.pkt.len=0;
nixnax	154:18b2bd92f557	182	ppp.ipData.ident=10000; // easy to recognize in ip packet dumps
nixnax	142:54d1543e23e5	183	ppp.ledState=0;
nixnax	142:54d1543e23e5	184	ppp.hdlc.frameStartIndex=0;
nixnax	146:a45f49a2b29c	185	ppp.responseCounter=0;
nixnax	142:54d1543e23e5	186	ppp.firstFrame=1;
nixnax	175:b4e6f8a6fe00	187	ppp.ppp = (pppHeaderType *)ppp.pkt.buf; // pointer to ppp header
nixnax	175:b4e6f8a6fe00	188	ppp.ip = (ipHeaderType *)(ppp.pkt.buf+4); // pointer to IP header
nixnax	142:54d1543e23e5	189	}
nixnax	142:54d1543e23e5	190
nixnax	142:54d1543e23e5	191	/// Toggle the LED on every second PPP packet received
nixnax	142:54d1543e23e5	192	void led1Toggle()
nixnax	142:54d1543e23e5	193	{
nixnax	142:54d1543e23e5	194	led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax	143:c5019f856a56	195	ppp.ledState++;
nixnax	142:54d1543e23e5	196	}
nixnax	142:54d1543e23e5	197
nixnax	179:ba2b2ddd0da5	198	/// Returns 1 after a connect message, 0 at startup or after a disconnect message
nixnax	150:3366bf3d294e	199	int connectedPpp()
nixnax	142:54d1543e23e5	200	{
nixnax	142:54d1543e23e5	201	return ppp.online;
nixnax	143:c5019f856a56	202	}
nixnax	142:54d1543e23e5	203
nixnax	179:ba2b2ddd0da5	204	/// PPP serial port receive interrupt handler.
nixnax	143:c5019f856a56	205	/// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax	143:c5019f856a56	206	/// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax	179:ba2b2ddd0da5	207	void pppReceiveHandler()
nixnax	142:54d1543e23e5	208	{
nixnax	142:54d1543e23e5	209	char ch;
nixnax	179:ba2b2ddd0da5	210	while ( pc.readable() ) {
nixnax	223:917b554cb8a5	211	int localHead = (ppp.rx.head+1); // local head index
nixnax	223:917b554cb8a5	212	if (localHead > RXBUFLEN) localHead=0; // increment and wrap head index
nixnax	223:917b554cb8a5	213	if ( localHead == ppp.rx.rtail ) {
nixnax	221:1d7c32d8256b	214	ppp.rx.bufferfull = 1; // set flag if rx buffer is full
nixnax	221:1d7c32d8256b	215	return; // don't read if rx buffer is full
nixnax	142:54d1543e23e5	216	}
nixnax	142:54d1543e23e5	217	ch = pc.getc(); // read new character
nixnax	142:54d1543e23e5	218	ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax	209:aa514cd631ee	219	if (ch == 0x7E) { // check for ppp frame start character
nixnax	209:aa514cd631ee	220	if ( ppp.online == 0 ) { // check if we are offline
nixnax	209:aa514cd631ee	221	ppp.online = 1; // if we see a frame start character we immediately change status to online
nixnax	142:54d1543e23e5	222	}
nixnax	142:54d1543e23e5	223	}
nixnax	223:917b554cb8a5	224	ppp.rx.head = localHead; // update real head pointer
nixnax	221:1d7c32d8256b	225	ppp.rx.buflevel++; // update buffer level counter
nixnax	209:aa514cd631ee	226	if ( ppp.rx.buflevel > ppp.rx.maxbuflevel ) {
nixnax	221:1d7c32d8256b	227	ppp.rx.maxbuflevel = ppp.rx.buflevel; // remember the maximum usage of rx buffer
nixnax	209:aa514cd631ee	228	}
nixnax	142:54d1543e23e5	229	}
nixnax	142:54d1543e23e5	230	}
nixnax	142:54d1543e23e5	231
nixnax	145:098b6ed2f7f2	232	/// update the cumulative PPP FCS (frame check sequence)
nixnax	226:4898247048c7	233	void fcsDo(register int x)
nixnax	142:54d1543e23e5	234	{
nixnax	220:54f45f924707	235	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1;
nixnax	220:54f45f924707	236	x>>=1;
nixnax	220:54f45f924707	237	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1;
nixnax	220:54f45f924707	238	x>>=1;
nixnax	220:54f45f924707	239	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1;
nixnax	220:54f45f924707	240	x>>=1;
nixnax	220:54f45f924707	241	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1;
nixnax	220:54f45f924707	242	x>>=1;
nixnax	220:54f45f924707	243	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1;
nixnax	220:54f45f924707	244	x>>=1;
nixnax	220:54f45f924707	245	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1;
nixnax	220:54f45f924707	246	x>>=1;
nixnax	220:54f45f924707	247	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1;
nixnax	220:54f45f924707	248	x>>=1;
nixnax	220:54f45f924707	249	ppp.fcs=((ppp.fcs&1)^(x&1))?(ppp.fcs>>1)^0x8408:ppp.fcs>>1;
nixnax	220:54f45f924707	250	x>>=1;
nixnax	142:54d1543e23e5	251	}
nixnax	142:54d1543e23e5	252
nixnax	145:098b6ed2f7f2	253	/// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax	145:098b6ed2f7f2	254	int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax	142:54d1543e23e5	255	{
nixnax	226:4898247048c7	256	ppp.fcs=0xffff; // fcs initial value
nixnax	145:098b6ed2f7f2	257	for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax	145:098b6ed2f7f2	258	return ppp.fcs;
nixnax	142:54d1543e23e5	259	}
nixnax	142:54d1543e23e5	260
nixnax	142:54d1543e23e5	261	/// Get one character from our received PPP buffer
nixnax	142:54d1543e23e5	262	int pc_getBuf()
nixnax	142:54d1543e23e5	263	{
nixnax	142:54d1543e23e5	264	int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax	216:e3c5a5b47295	265	ppp.rx.tail=ppp.rx.tail+1;
nixnax	216:e3c5a5b47295	266	if (ppp.rx.tail > RXBUFLEN) ppp.rx.tail=0;
nixnax	142:54d1543e23e5	267	ppp.rx.buflevel--;
nixnax	142:54d1543e23e5	268	return x;
nixnax	142:54d1543e23e5	269	}
nixnax	142:54d1543e23e5	270
nixnax	142:54d1543e23e5	271	/// Dump a PPP frame to the debug serial port
nixnax	142:54d1543e23e5	272	/// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax	142:54d1543e23e5	273	/// Capture the frame's hex output in your terminal program and save as a text file
nixnax	164:c3de3d212c4b	274	/// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax	142:54d1543e23e5	275	void dumpPPPFrame()
nixnax	142:54d1543e23e5	276	{
nixnax	142:54d1543e23e5	277	char pbuf[30];
nixnax	142:54d1543e23e5	278	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	210:a2a651249a9a	279
nixnax	142:54d1543e23e5	280	sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax	210:a2a651249a9a	281
nixnax	221:1d7c32d8256b	282	debugPuts(pbuf);
nixnax	142:54d1543e23e5	283	}
nixnax	210:a2a651249a9a	284
nixnax	142:54d1543e23e5	285	sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax	210:a2a651249a9a	286
nixnax	221:1d7c32d8256b	287	debugPuts(pbuf);
nixnax	142:54d1543e23e5	288	}
nixnax	142:54d1543e23e5	289
nixnax	142:54d1543e23e5	290	/// Process a received PPP frame
nixnax	142:54d1543e23e5	291	void processPPPFrame(int start, int end)
nixnax	142:54d1543e23e5	292	{
nixnax	226:4898247048c7	293	led1Toggle(); // change led1 state on received frames
nixnax	142:54d1543e23e5	294	if(start==end) {
nixnax	142:54d1543e23e5	295	return; // empty frame
nixnax	142:54d1543e23e5	296	}
nixnax	226:4898247048c7	297	ppp.fcs=0xffff; // fcs initial value
nixnax	142:54d1543e23e5	298	char * dest = ppp.pkt.buf;
nixnax	142:54d1543e23e5	299	ppp.pkt.len=0;
nixnax	142:54d1543e23e5	300	int unstuff=0;
nixnax	142:54d1543e23e5	301	int idx = start;
nixnax	142:54d1543e23e5	302	while(1) {
nixnax	142:54d1543e23e5	303	if (unstuff==0) {
nixnax	142:54d1543e23e5	304	if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax	142:54d1543e23e5	305	else {
nixnax	142:54d1543e23e5	306	*dest = ppp.rx.buf[idx];
nixnax	142:54d1543e23e5	307	ppp.pkt.len++;
nixnax	142:54d1543e23e5	308	dest++;
nixnax	145:098b6ed2f7f2	309	fcsDo(ppp.rx.buf[idx]);
nixnax	142:54d1543e23e5	310	}
nixnax	142:54d1543e23e5	311	} else { // unstuff characters prefixed with 0x7d
nixnax	142:54d1543e23e5	312	*dest = ppp.rx.buf[idx]^0x20;
nixnax	142:54d1543e23e5	313	ppp.pkt.len++;
nixnax	142:54d1543e23e5	314	dest++;
nixnax	145:098b6ed2f7f2	315	fcsDo(ppp.rx.buf[idx]^0x20);
nixnax	142:54d1543e23e5	316	unstuff=0;
nixnax	142:54d1543e23e5	317	}
nixnax	216:e3c5a5b47295	318	idx = idx+1;
nixnax	216:e3c5a5b47295	319	if (idx > RXBUFLEN) idx=0;
nixnax	142:54d1543e23e5	320	if (idx == end) break;
nixnax	142:54d1543e23e5	321	}
nixnax	145:098b6ed2f7f2	322	ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax	226:4898247048c7	323	#ifdef DUMP_RECEIVED_PPP_FRAMES_YES
nixnax	226:4898247048c7	324	dumpPPPFrame(); // hex dump ALL ppp frames to the debug port
nixnax	226:4898247048c7	325	#endif
nixnax	142:54d1543e23e5	326	if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax	142:54d1543e23e5	327	determinePacketType();
nixnax	142:54d1543e23e5	328	} else {
nixnax	142:54d1543e23e5	329	#define REPORT_FCS_ERROR_YES
nixnax	142:54d1543e23e5	330	#ifdef REPORT_FCS_ERROR_YES
nixnax	142:54d1543e23e5	331	char pbuf[50]; // local print buffer
nixnax	142:54d1543e23e5	332	sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax	221:1d7c32d8256b	333	debugPuts( pbuf );
nixnax	226:4898247048c7	334	#define DUMP_PPP_FRAME_ON_ERROR_NO
nixnax	226:4898247048c7	335	#ifdef DUMP_PPP_FRAME_ON_ERROR_YES
nixnax	226:4898247048c7	336	dumpPPPFrame(); // dump frames with errors in them
nixnax	226:4898247048c7	337	#endif
nixnax	142:54d1543e23e5	338	#endif
nixnax	142:54d1543e23e5	339	}
nixnax	142:54d1543e23e5	340	}
nixnax	142:54d1543e23e5	341
nixnax	142:54d1543e23e5	342	/// do PPP HDLC-like handling of special (flag) characters
nixnax	143:c5019f856a56	343	void hdlcPut(int ch)
nixnax	142:54d1543e23e5	344	{
nixnax	142:54d1543e23e5	345	if ( (ch<0x20) \|\| (ch==0x7d) \|\| (ch==0x7e) ) {
nixnax	226:4898247048c7	346	pc.putc(0x7d);
nixnax	226:4898247048c7	347	pc.putc(ch^0x20); // these characters need special handling
nixnax	142:54d1543e23e5	348	} else {
nixnax	226:4898247048c7	349	pc.putc(ch);
nixnax	142:54d1543e23e5	350	}
nixnax	142:54d1543e23e5	351	}
nixnax	142:54d1543e23e5	352
nixnax	142:54d1543e23e5	353	/// send a PPP frame in HDLC format
nixnax	144:01d98cf7738e	354	void sendPppFrame()
nixnax	143:c5019f856a56	355	{
nixnax	172:449dd7a28955	356	ppp.responseCounter++; // count the number of ppp frames we send
nixnax	145:098b6ed2f7f2	357	int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax	142:54d1543e23e5	358	ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax	142:54d1543e23e5	359	ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax	226:4898247048c7	360	pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax	142:54d1543e23e5	361	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	226:4898247048c7	362	// wait_us(86); // wait one character time
nixnax	210:a2a651249a9a	363
nixnax	142:54d1543e23e5	364	hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax	142:54d1543e23e5	365	}
nixnax	226:4898247048c7	366	pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax	142:54d1543e23e5	367	}
nixnax	142:54d1543e23e5	368
nixnax	143:c5019f856a56	369	/// 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	370	int bufferToIP(char * buffer)
nixnax	143:c5019f856a56	371	{
nixnax	143:c5019f856a56	372	int result=0;
nixnax	143:c5019f856a56	373	for(int i=0; i<4; i++) result = (result<<8)\|(*buffer++ & 0xff);
nixnax	143:c5019f856a56	374	return result;
nixnax	143:c5019f856a56	375	}
nixnax	143:c5019f856a56	376
nixnax	177:dab9e685af53	377	/// convert 4-byte ip address to 32-bit
nixnax	228:7fb878500862	378	unsigned int integersToIp( int a, int b, int c, int d)
nixnax	179:ba2b2ddd0da5	379	{
nixnax	177:dab9e685af53	380	return a<<24 \| b<<16 \| c<<8 \| d;
nixnax	177:dab9e685af53	381	}
nixnax	177:dab9e685af53	382
nixnax	142:54d1543e23e5	383	/// handle IPCP configuration requests
nixnax	142:54d1543e23e5	384	void ipcpConfigRequestHandler()
nixnax	142:54d1543e23e5	385	{
nixnax	142:54d1543e23e5	386	debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax	173:6774a0c851c4	387	if(ppp.ipcp->request[0]==3) {
nixnax	143:c5019f856a56	388	ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax	173:6774a0c851c4	389	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	390	}
nixnax	143:c5019f856a56	391
nixnax	167:ff8a2d8beeb1	392	ppp.ipcp->code=2; // change code to ack
nixnax	144:01d98cf7738e	393	sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax	142:54d1543e23e5	394
nixnax	142:54d1543e23e5	395	debugPrintf("Our IPCP Ask (no options)\n");
nixnax	167:ff8a2d8beeb1	396	ppp.ipcp->code=1; // change code to request
nixnax	167:ff8a2d8beeb1	397	ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax	167:ff8a2d8beeb1	398	ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax	144:01d98cf7738e	399	sendPppFrame(); // send our request
nixnax	142:54d1543e23e5	400	}
nixnax	142:54d1543e23e5	401
nixnax	142:54d1543e23e5	402	/// handle IPCP acknowledge (do nothing)
nixnax	142:54d1543e23e5	403	void ipcpAckHandler()
nixnax	142:54d1543e23e5	404	{
nixnax	142:54d1543e23e5	405	debugPrintf("Their IPCP Grant\n");
nixnax	142:54d1543e23e5	406	}
nixnax	142:54d1543e23e5	407
nixnax	143:c5019f856a56	408	/// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax	143:c5019f856a56	409	/// 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	410	void ipcpNackHandler()
nixnax	142:54d1543e23e5	411	{
nixnax	146:a45f49a2b29c	412	debugPrintf("Their IPCP Nack\n");
nixnax	173:6774a0c851c4	413	if (ppp.ipcp->request[0]==3) { // check if the NACK contains an IP address parameter
nixnax	167:ff8a2d8beeb1	414	ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax	144:01d98cf7738e	415	sendPppFrame(); // let's request this IP address as ours
nixnax	143:c5019f856a56	416	debugPrintf("Our IPCP ACK (received an IP)\n");
nixnax	146:a45f49a2b29c	417	} else { // if it's not an IP nack we ignore it
nixnax	146:a45f49a2b29c	418	debugPrintf("IPCP Nack Ignored\n");
nixnax	146:a45f49a2b29c	419	}
nixnax	142:54d1543e23e5	420	}
nixnax	142:54d1543e23e5	421
nixnax	142:54d1543e23e5	422	/// handle all other IPCP requests (by ignoring them)
nixnax	142:54d1543e23e5	423	void ipcpDefaultHandler()
nixnax	142:54d1543e23e5	424	{
nixnax	142:54d1543e23e5	425	debugPrintf("Their IPCP Other\n");
nixnax	142:54d1543e23e5	426	}
nixnax	142:54d1543e23e5	427
nixnax	142:54d1543e23e5	428	/// process an incoming IPCP packet
nixnax	142:54d1543e23e5	429	void IPCPframe()
nixnax	142:54d1543e23e5	430	{
nixnax	167:ff8a2d8beeb1	431	int action = ppp.ipcp->code; // packet type is here
nixnax	167:ff8a2d8beeb1	432	switch (action) {
nixnax	142:54d1543e23e5	433	case 1:
nixnax	142:54d1543e23e5	434	ipcpConfigRequestHandler();
nixnax	142:54d1543e23e5	435	break;
nixnax	142:54d1543e23e5	436	case 2:
nixnax	142:54d1543e23e5	437	ipcpAckHandler();
nixnax	142:54d1543e23e5	438	break;
nixnax	142:54d1543e23e5	439	case 3:
nixnax	142:54d1543e23e5	440	ipcpNackHandler();
nixnax	142:54d1543e23e5	441	break;
nixnax	142:54d1543e23e5	442	default:
nixnax	142:54d1543e23e5	443	ipcpDefaultHandler();
nixnax	142:54d1543e23e5	444	}
nixnax	142:54d1543e23e5	445	}
nixnax	142:54d1543e23e5	446
nixnax	142:54d1543e23e5	447	/// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax	161:d59f778bc8ab	448	unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax	142:54d1543e23e5	449	{
nixnax	159:4d1bf96a59cd	450	unsigned int i,hi,lo;
nixnax	142:54d1543e23e5	451	unsigned char placeHolder;
nixnax	161:d59f778bc8ab	452	if (restart) ppp.sum=0;
nixnax	142:54d1543e23e5	453	if (len&1) {
nixnax	142:54d1543e23e5	454	placeHolder = ptr[len];
nixnax	142:54d1543e23e5	455	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	456	}
nixnax	142:54d1543e23e5	457	i=0;
nixnax	142:54d1543e23e5	458	while ( i<len ) {
nixnax	210:a2a651249a9a	459
nixnax	142:54d1543e23e5	460	hi = ptr[i++];
nixnax	142:54d1543e23e5	461	lo = ptr[i++];
nixnax	159:4d1bf96a59cd	462	ppp.sum = ppp.sum + ((hi<<8)\|lo);
nixnax	142:54d1543e23e5	463	}
nixnax	142:54d1543e23e5	464	if (len&1) {
nixnax	142:54d1543e23e5	465	ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax	142:54d1543e23e5	466	}
nixnax	159:4d1bf96a59cd	467	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax	159:4d1bf96a59cd	468	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax	159:4d1bf96a59cd	469	return ~ppp.sum;
nixnax	142:54d1543e23e5	470	}
nixnax	142:54d1543e23e5	471
nixnax	142:54d1543e23e5	472	/// perform the checksum on an IP header
nixnax	146:a45f49a2b29c	473	void IpHeaderCheckSum()
nixnax	142:54d1543e23e5	474	{
nixnax	161:d59f778bc8ab	475	ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax	161:d59f778bc8ab	476	int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax	161:d59f778bc8ab	477	unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax	161:d59f778bc8ab	478	ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax	146:a45f49a2b29c	479	}
nixnax	146:a45f49a2b29c	480
nixnax	147:0f40005cbc5f	481	/// swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	482	void swapIpAddresses()
nixnax	147:0f40005cbc5f	483	{
nixnax	162:594729c0e5c1	484	unsigned int tempHold;
nixnax	162:594729c0e5c1	485	tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax	162:594729c0e5c1	486	ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax	162:594729c0e5c1	487	ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax	147:0f40005cbc5f	488	}
nixnax	147:0f40005cbc5f	489
nixnax	149:969d98f6fb88	490	/// swap the IP source and destination ports
nixnax	149:969d98f6fb88	491	void swapIpPorts()
nixnax	149:969d98f6fb88	492	{
nixnax	173:6774a0c851c4	493	int headerSizeIP = 4 * (ppp.ip->headerLength); // calculate size of IP header
nixnax	173:6774a0c851c4	494	char * ipSrcPort = ppp.ipStart + headerSizeIP + 0; // ip source port location
nixnax	173:6774a0c851c4	495	char * ipDstPort = ppp.ipStart + headerSizeIP + 2; // ip destin port location
nixnax	149:969d98f6fb88	496	char tempHold[2];
nixnax	149:969d98f6fb88	497	memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax	149:969d98f6fb88	498	memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax	149:969d98f6fb88	499	memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax	149:969d98f6fb88	500	}
nixnax	149:969d98f6fb88	501
nixnax	170:3d3b2126181c	502	/// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax	170:3d3b2126181c	503	void checkSumPseudoHeader( unsigned int packetLength )
nixnax	170:3d3b2126181c	504	{
nixnax	170:3d3b2126181c	505	// 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	506	pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax	170:3d3b2126181c	507	pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax	170:3d3b2126181c	508	pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax	170:3d3b2126181c	509	pseudoHeader.zero = 0; // zero byte
nixnax	170:3d3b2126181c	510	pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax	170:3d3b2126181c	511	pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax	170:3d3b2126181c	512	dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax	170:3d3b2126181c	513	}
nixnax	170:3d3b2126181c	514
nixnax	171:46b36d4edd1d	515	/// initialize an IP packet to send
nixnax	171:46b36d4edd1d	516	void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax	171:46b36d4edd1d	517	{
nixnax	171:46b36d4edd1d	518	ppp.ppp->address = 0xff;
nixnax	171:46b36d4edd1d	519	ppp.ppp->control = 3;
nixnax	171:46b36d4edd1d	520	ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax	171:46b36d4edd1d	521	ppp.ip->version = 4;
nixnax	171:46b36d4edd1d	522	ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax	171:46b36d4edd1d	523	ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax	171:46b36d4edd1d	524	ppp.ip->dontFragment=1;
nixnax	171:46b36d4edd1d	525	ppp.ip->ttl=128;
nixnax	171:46b36d4edd1d	526	ppp.ip->protocol = protocol; // udp
nixnax	171:46b36d4edd1d	527	ppp.ip->srcAdrR = __REV(srcIp);
nixnax	171:46b36d4edd1d	528	ppp.ip->dstAdrR = __REV(dstIp);
nixnax	171:46b36d4edd1d	529	ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax	171:46b36d4edd1d	530	ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax	171:46b36d4edd1d	531	ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax	171:46b36d4edd1d	532	}
nixnax	171:46b36d4edd1d	533
nixnax	171:46b36d4edd1d	534
nixnax	171:46b36d4edd1d	535	/// Build a UDP packet from scratch
nixnax	171:46b36d4edd1d	536	void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax	171:46b36d4edd1d	537	{
nixnax	171:46b36d4edd1d	538	struct {
nixnax	171:46b36d4edd1d	539	unsigned int ipAll; // length of entire ip packet
nixnax	171:46b36d4edd1d	540	unsigned int ipHeader; // length of ip header
nixnax	171:46b36d4edd1d	541	unsigned int udpAll; // length of entire udp packet
nixnax	171:46b36d4edd1d	542	unsigned int udpData; // length of udp data segment
nixnax	171:46b36d4edd1d	543	} len;
nixnax	171:46b36d4edd1d	544	len.ipHeader = 20; // ip header length
nixnax	171:46b36d4edd1d	545	len.udpData = msgLen; // udp data size
nixnax	171:46b36d4edd1d	546	len.udpAll = len.udpData+8; // update local udp packet length
nixnax	171:46b36d4edd1d	547	len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax	171:46b36d4edd1d	548	initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax	171:46b36d4edd1d	549	ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax	171:46b36d4edd1d	550	ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax	171:46b36d4edd1d	551	memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax	171:46b36d4edd1d	552	ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax	171:46b36d4edd1d	553	ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	554	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	555	checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	556	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	557	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	558	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	559	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	560	}
nixnax	171:46b36d4edd1d	561
nixnax	146:a45f49a2b29c	562	/// Process an incoming UDP packet.
nixnax	146:a45f49a2b29c	563	/// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax	146:a45f49a2b29c	564	void UDPpacket()
nixnax	146:a45f49a2b29c	565	{
nixnax	163:d1b4328e9f08	566	struct {
nixnax	163:d1b4328e9f08	567	unsigned int all; // length of entire ip packet
nixnax	163:d1b4328e9f08	568	unsigned int header; // length of ip header
nixnax	163:d1b4328e9f08	569	} ipLength;
nixnax	163:d1b4328e9f08	570
nixnax	163:d1b4328e9f08	571	struct {
nixnax	165:c47826d07e0d	572	unsigned int all; // length of entire udp packet
nixnax	163:d1b4328e9f08	573	unsigned int data; // length of udp data segment
nixnax	163:d1b4328e9f08	574	} udpLength;
nixnax	163:d1b4328e9f08	575
nixnax	163:d1b4328e9f08	576	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	163:d1b4328e9f08	577	ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	171:46b36d4edd1d	578	udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax	163:d1b4328e9f08	579	udpLength.data = udpLength.all - 8; // size of udp data
nixnax	147:0f40005cbc5f	580
nixnax	146:a45f49a2b29c	581	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	171:46b36d4edd1d	582	char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax	171:46b36d4edd1d	583	char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax	163:d1b4328e9f08	584
nixnax	171:46b36d4edd1d	585	unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax	171:46b36d4edd1d	586	unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax	163:d1b4328e9f08	587
nixnax	163:d1b4328e9f08	588	if(v0) {
nixnax	163:d1b4328e9f08	589	debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax	163:d1b4328e9f08	590	debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax	163:d1b4328e9f08	591	debugPrintf("Len %03d", udpLength);
nixnax	163:d1b4328e9f08	592	}
nixnax	146:a45f49a2b29c	593	if (v1) {
nixnax	163:d1b4328e9f08	594	int printSize = udpLength.data;
nixnax	146:a45f49a2b29c	595	if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax	146:a45f49a2b29c	596	for (int i=0; i<printSize; i++) {
nixnax	163:d1b4328e9f08	597	char ch = ppp.udp->data[i];
nixnax	146:a45f49a2b29c	598	if (ch>31 && ch<127) {
nixnax	146:a45f49a2b29c	599	debugPrintf("%c", ch);
nixnax	146:a45f49a2b29c	600	} else {
nixnax	146:a45f49a2b29c	601	debugPrintf("_");
nixnax	146:a45f49a2b29c	602	}
nixnax	146:a45f49a2b29c	603	}
nixnax	146:a45f49a2b29c	604	}
nixnax	146:a45f49a2b29c	605	if (v0) debugPrintf("\n");
nixnax	146:a45f49a2b29c	606	#endif
nixnax	163:d1b4328e9f08	607	int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax	163:d1b4328e9f08	608	int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax	146:a45f49a2b29c	609	if ( (echoFound) \|\| (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax	146:a45f49a2b29c	610	if (echoFound) {
nixnax	171:46b36d4edd1d	611	swapIpAddresses(); // swap IP source and destination
nixnax	171:46b36d4edd1d	612	swapIpPorts(); // swap IP source and destination ports
nixnax	163:d1b4328e9f08	613	memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax	170:3d3b2126181c	614	int n=0;
nixnax	170:3d3b2126181c	615	n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax	168:c77eb908042a	616	udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax	171:46b36d4edd1d	617	// we may have changed data length, update all the lengths
nixnax	171:46b36d4edd1d	618	udpLength.all = udpLength.data+8; // update local udp packet length
nixnax	171:46b36d4edd1d	619	ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax	171:46b36d4edd1d	620	ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax	171:46b36d4edd1d	621	ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax	171:46b36d4edd1d	622	ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	623	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	624	checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	625	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	626	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	627	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	628	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	629	} else if ( testFound ) {
nixnax	171:46b36d4edd1d	630	unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax	171:46b36d4edd1d	631	unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax	171:46b36d4edd1d	632	unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax	171:46b36d4edd1d	633	unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax	172:449dd7a28955	634	int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter);
nixnax	171:46b36d4edd1d	635	sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax	146:a45f49a2b29c	636	}
nixnax	146:a45f49a2b29c	637	}
nixnax	142:54d1543e23e5	638	}
nixnax	142:54d1543e23e5	639
nixnax	174:e5a3f16421a5	640	/// UDP demo that sends a udp packet containing a character received from the second debug serial port.
nixnax	174:e5a3f16421a5	641	/// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
nixnax	178:3f17aa0ce5ce	642	/// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
nixnax	178:3f17aa0ce5ce	643	/// See http://www.wikihow.com/Enable-IP-Routing.
nixnax	179:ba2b2ddd0da5	644	/// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
nixnax	179:ba2b2ddd0da5	645	/// The netcat UDP receive command on the remote host would be: nc -ul 12345
nixnax	174:e5a3f16421a5	646	void sendUdpData()
nixnax	174:e5a3f16421a5	647	{
nixnax	174:e5a3f16421a5	648	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	179:ba2b2ddd0da5	649	if (ppp.online) {
nixnax	179:ba2b2ddd0da5	650	if (xx.readable()) {
nixnax	179:ba2b2ddd0da5	651	char inchar = xx.getc();
nixnax	179:ba2b2ddd0da5	652	xx.putc( inchar ); // echo the received character on the debug serial port
nixnax	228:7fb878500862	653	sendUdp(integersToIp(172,10,10,2), integersToIp(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	654	}
nixnax	174:e5a3f16421a5	655	}
nixnax	174:e5a3f16421a5	656	#endif
nixnax	174:e5a3f16421a5	657	}
nixnax	174:e5a3f16421a5	658
nixnax	142:54d1543e23e5	659	/// handle a PING ICMP (internet control message protocol) packet
nixnax	142:54d1543e23e5	660	void ICMPpacket() // internet control message protocol
nixnax	142:54d1543e23e5	661	{
nixnax	165:c47826d07e0d	662	struct {
nixnax	165:c47826d07e0d	663	unsigned int all; // length of entire ip packet
nixnax	165:c47826d07e0d	664	unsigned int header; // length of ip header
nixnax	165:c47826d07e0d	665	} ipLength;
nixnax	165:c47826d07e0d	666	struct {
nixnax	165:c47826d07e0d	667	unsigned int all; // length of entire udp packet
nixnax	165:c47826d07e0d	668	unsigned int data; // length of udp data segment
nixnax	165:c47826d07e0d	669	} icmpLength;
nixnax	165:c47826d07e0d	670	ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax	165:c47826d07e0d	671	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	165:c47826d07e0d	672	ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	165:c47826d07e0d	673	icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax	165:c47826d07e0d	674	icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax	142:54d1543e23e5	675	#define ICMP_TYPE_PING_REQUEST 8
nixnax	165:c47826d07e0d	676	if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax	165:c47826d07e0d	677	ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax	147:0f40005cbc5f	678	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	167:ff8a2d8beeb1	679	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	680	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	165:c47826d07e0d	681	int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax	165:c47826d07e0d	682	int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax	142:54d1543e23e5	683	if(1) {
nixnax	142:54d1543e23e5	684	char pbuf[50];
nixnax	210:a2a651249a9a	685
nixnax	142:54d1543e23e5	686	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	221:1d7c32d8256b	687	debugPuts( pbuf );
nixnax	210:a2a651249a9a	688
nixnax	142:54d1543e23e5	689	sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax	210:a2a651249a9a	690
nixnax	221:1d7c32d8256b	691	debugPuts( pbuf );
nixnax	142:54d1543e23e5	692	}
nixnax	142:54d1543e23e5	693	#endif
nixnax	147:0f40005cbc5f	694	swapIpAddresses(); // swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	695	IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax	142:54d1543e23e5	696	#define ICMP_TYPE_ECHO_REPLY 0
nixnax	165:c47826d07e0d	697	ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax	165:c47826d07e0d	698	ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax	165:c47826d07e0d	699	unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax	165:c47826d07e0d	700	ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax	226:4898247048c7	701	#define DUMP_ICMP_PACKETS_NO
nixnax	226:4898247048c7	702	#ifdef DUMP_ICMP_PACKETS_YES
nixnax	165:c47826d07e0d	703	int printSize = icmpLength.data; // exclude size of icmp header
nixnax	142:54d1543e23e5	704	if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax	226:4898247048c7	705	for (int i=0; i<printSize; i++) {
nixnax	226:4898247048c7	706	char ch = ppp.icmp->data[i];
nixnax	226:4898247048c7	707	if (ch>31 && ch<127) {
nixnax	226:4898247048c7	708	debugPutc(ch);
nixnax	226:4898247048c7	709	} else {
nixnax	226:4898247048c7	710	debugPutc('_'); // for non-printable characters
nixnax	142:54d1543e23e5	711	}
nixnax	142:54d1543e23e5	712	}
nixnax	226:4898247048c7	713	debugPutc('\n');
nixnax	226:4898247048c7	714	#endif
nixnax	144:01d98cf7738e	715	sendPppFrame(); // reply to the ping
nixnax	142:54d1543e23e5	716	} else {
nixnax	142:54d1543e23e5	717	if (v0) {
nixnax	165:c47826d07e0d	718	debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax	142:54d1543e23e5	719	}
nixnax	142:54d1543e23e5	720	}
nixnax	142:54d1543e23e5	721	}
nixnax	142:54d1543e23e5	722
nixnax	142:54d1543e23e5	723	/// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax	142:54d1543e23e5	724	void IGMPpacket()
nixnax	142:54d1543e23e5	725	{
nixnax	142:54d1543e23e5	726	if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax	142:54d1543e23e5	727	}
nixnax	142:54d1543e23e5	728
nixnax	142:54d1543e23e5	729	/// dump the header of an IP pakcet on the (optional) debug serial port
nixnax	142:54d1543e23e5	730	void dumpHeaderIP (int outGoing)
nixnax	142:54d1543e23e5	731	{
nixnax	142:54d1543e23e5	732	#if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	210:a2a651249a9a	733
nixnax	155:9c6a1d249e26	734	int IPv4Id = __REV16(ppp.ip->identR);
nixnax	152:025c73b6c0a9	735	char pbuf[80]; // local print buffer
nixnax	142:54d1543e23e5	736	int n=0;
nixnax	142:54d1543e23e5	737	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	142:54d1543e23e5	738	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	739	#define DUMP_FULL_IP_ADDRESS_YES
nixnax	142:54d1543e23e5	740	#ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax	167:ff8a2d8beeb1	741	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	742	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	142:54d1543e23e5	743	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	744	#endif
nixnax	221:1d7c32d8256b	745	debugPuts( pbuf );
nixnax	142:54d1543e23e5	746	#ifndef TCP_HEADER_DUMP_YES
nixnax	221:1d7c32d8256b	747	debugPuts('\x1b[30m\n'); // if there's no TCP header dump we terminate the line with \n and VT100 code for black
nixnax	142:54d1543e23e5	748	#endif
nixnax	142:54d1543e23e5	749	#endif
nixnax	142:54d1543e23e5	750	}
nixnax	142:54d1543e23e5	751
nixnax	142:54d1543e23e5	752	/// dump a TCP header on the optional debug serial port
nixnax	142:54d1543e23e5	753	void dumpHeaderTCP(int outGoing)
nixnax	142:54d1543e23e5	754	{
nixnax	142:54d1543e23e5	755	#if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	155:9c6a1d249e26	756	char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax	142:54d1543e23e5	757	#define PRINT_ALL_TCP_FLAGS_YES
nixnax	142:54d1543e23e5	758	#ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax	155:9c6a1d249e26	759	memset(flagString,'.', 8); // fill string with "........"
nixnax	156:163c23249731	760	if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax	156:163c23249731	761	if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax	156:163c23249731	762	if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax	156:163c23249731	763	if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax	156:163c23249731	764	if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax	156:163c23249731	765	if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax	156:163c23249731	766	if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax	156:163c23249731	767	if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax	155:9c6a1d249e26	768	flagString[8]=0; // null terminate string
nixnax	142:54d1543e23e5	769	#else
nixnax	156:163c23249731	770	if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax	156:163c23249731	771	if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax	156:163c23249731	772	if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax	156:163c23249731	773	if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax	156:163c23249731	774	if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax	155:9c6a1d249e26	775	flagString[1]=0; // null terminate string
nixnax	142:54d1543e23e5	776	#endif
nixnax	221:1d7c32d8256b	777	debugPuts( flagString );
nixnax	142:54d1543e23e5	778	#define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	142:54d1543e23e5	779	#ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	221:1d7c32d8256b	780	debugPuts("\x1b[30m\n"); // write a black color and newline after every packet
nixnax	160:bd701ad564cb	781	#else
nixnax	221:1d7c32d8256b	782	debugPuts("\x1b[30m"); // write a black color after every packet
nixnax	142:54d1543e23e5	783	#endif
nixnax	156:163c23249731	784	if( outGoing && ppp.tcp->flag.fin ) { // ACK/FIN - if this is an outgoing FIN it's the end of a tcp conversation
nixnax	221:1d7c32d8256b	785	debugPutc('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax	142:54d1543e23e5	786	}
nixnax	142:54d1543e23e5	787	#endif
nixnax	142:54d1543e23e5	788	}
nixnax	142:54d1543e23e5	789
nixnax	143:c5019f856a56	790	/// Encode a buffer in base-64
nixnax	184:4133f557d4d4	791	const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax	142:54d1543e23e5	792	void enc64(char * in, char * out, int len)
nixnax	142:54d1543e23e5	793	{
nixnax	142:54d1543e23e5	794	int i,j,a,b,c;
nixnax	142:54d1543e23e5	795	i=0;
nixnax	142:54d1543e23e5	796	j=0;
nixnax	142:54d1543e23e5	797	while(1) {
nixnax	142:54d1543e23e5	798	if (i<len) {
nixnax	142:54d1543e23e5	799	a = in[i++];
nixnax	142:54d1543e23e5	800	out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax	142:54d1543e23e5	801	} else break;
nixnax	142:54d1543e23e5	802	if (i<len) {
nixnax	142:54d1543e23e5	803	b = in[i++];
nixnax	142:54d1543e23e5	804	out[j++] = lut[ ( (a << 4) & 0x30) \| ( (b >> 4) & 0x0f) ];
nixnax	142:54d1543e23e5	805	out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax	142:54d1543e23e5	806	} else out[j++] = '=';
nixnax	142:54d1543e23e5	807	if (i<len) {
nixnax	142:54d1543e23e5	808	c = in[i++];
nixnax	142:54d1543e23e5	809	j--;
nixnax	142:54d1543e23e5	810	out[j++] = lut[ ( (b << 2) & 0x3c) \| ( (c >> 6) & 0x03) ];
nixnax	142:54d1543e23e5	811	out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax	142:54d1543e23e5	812	} else out[j++] = '=';
nixnax	142:54d1543e23e5	813	}
nixnax	142:54d1543e23e5	814	out[j]=0;
nixnax	142:54d1543e23e5	815	}
nixnax	142:54d1543e23e5	816
nixnax	160:bd701ad564cb	817	/// Handle a request for an http websocket.
nixnax	160:bd701ad564cb	818	/// 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	819	int webSocketHandler(char * dataStart)
nixnax	142:54d1543e23e5	820	{
nixnax	142:54d1543e23e5	821	int n=0; // byte counter
nixnax	184:4133f557d4d4	822	char * key = strstr(dataStart, "Sec-WebSocket-Key:"); // search for the key in the payload
nixnax	142:54d1543e23e5	823	if (key != NULL) {
nixnax	184:4133f557d4d4	824	key = key + 18; // skip over the key ident string "Sec-WebSocket-Key:"
nixnax	221:1d7c32d8256b	825	if (v0) debugPuts("WebSocket Request\n");
nixnax	184:4133f557d4d4	826	while ( strchr(lut, *key) == NULL) key++; // skip non-valid base-64 characters (whitespace)
nixnax	184:4133f557d4d4	827	char challenge [80];
nixnax	184:4133f557d4d4	828	int i=0;
nixnax	184:4133f557d4d4	829	char * copyTo = challenge;
nixnax	184:4133f557d4d4	830	while (strchr(lut, *key) != NULL) { // copy while we see valid base-64 characters
nixnax	184:4133f557d4d4	831	if (i++ >40) break; // prevent buffer overflow
nixnax	184:4133f557d4d4	832	copyTo++ = key++; // copy next valid base-64 character
nixnax	184:4133f557d4d4	833	}
nixnax	184:4133f557d4d4	834	strcpy(copyTo,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // append websocket gui code
nixnax	226:4898247048c7	835	#define DUMP_WEBSOCKET_CHALLENGE_NO
nixnax	226:4898247048c7	836	#ifdef DUMP_WEBSOCKET_CHALLENGE_YES
nixnax	226:4898247048c7	837	debugPrintf("Challenge is %s\n", challenge); // the string we hash for the challenge
nixnax	227:f87156f9ef11	838	#endif
nixnax	142:54d1543e23e5	839	char shaOutput [20]; // sha1 output
nixnax	184:4133f557d4d4	840	sha1( shaOutput, challenge, strlen(challenge)); // hash the challenge
nixnax	142:54d1543e23e5	841	char encOut[50];
nixnax	184:4133f557d4d4	842	enc64( shaOutput, encOut, 20); // base-64 encode
nixnax	142:54d1543e23e5	843	char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax	142:54d1543e23e5	844	char * version = challenge;
nixnax	184:4133f557d4d4	845	strncpy(version, versionstring,70); // copy their version string
nixnax	142:54d1543e23e5	846	*strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax	142:54d1543e23e5	847	memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax	142:54d1543e23e5	848	n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax	142:54d1543e23e5	849	n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax	142:54d1543e23e5	850	n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax	142:54d1543e23e5	851	n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax	142:54d1543e23e5	852	n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax	142:54d1543e23e5	853	n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax	142:54d1543e23e5	854	n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax	142:54d1543e23e5	855	}
nixnax	142:54d1543e23e5	856	return n; // this response should satisfy a web browser's websocket protocol request
nixnax	142:54d1543e23e5	857	}
nixnax	142:54d1543e23e5	858
nixnax	142:54d1543e23e5	859	#define TCP_FLAG_ACK (1<<4)
nixnax	142:54d1543e23e5	860	#define TCP_FLAG_SYN (1<<1)
nixnax	142:54d1543e23e5	861	#define TCP_FLAG_PSH (1<<3)
nixnax	142:54d1543e23e5	862	#define TCP_FLAG_RST (1<<2)
nixnax	142:54d1543e23e5	863	#define TCP_FLAG_FIN (1<<0)
nixnax	142:54d1543e23e5	864
nixnax	142:54d1543e23e5	865	/// respond to an HTTP request
nixnax	185:4cd8f91e9d49	866	int httpResponse(char * dataStart, int * flags)
nixnax	142:54d1543e23e5	867	{
nixnax	142:54d1543e23e5	868	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	869	n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax	160:bd701ad564cb	870	if (n>0) return n; // if n>0 we already have a response, so return
nixnax	142:54d1543e23e5	871
nixnax	142:54d1543e23e5	872	int nHeader; // byte size of HTTP header
nixnax	142:54d1543e23e5	873	int contentLengthStart; // index where HTML starts
nixnax	142:54d1543e23e5	874	int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax	185:4cd8f91e9d49	875	*flags = TCP_FLAG_ACK \| TCP_FLAG_FIN; // the default case is that we close the connection
nixnax	142:54d1543e23e5	876
nixnax	142:54d1543e23e5	877	httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax	142:54d1543e23e5	878	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	879	httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	880	httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	881	// for example, you could try this using netcat (nc): echo "GET /x" \| nc 172.10.10.2
nixnax	210:a2a651249a9a	882	if( (httpGetRoot==0) \|\| (httpGetx==0) \|\| (httpGet5 == 'w') ) {
nixnax	142:54d1543e23e5	883	n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax	142:54d1543e23e5	884	} else {
nixnax	142:54d1543e23e5	885	n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax	142:54d1543e23e5	886	}
nixnax	142:54d1543e23e5	887	n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax	142:54d1543e23e5	888	contentLengthStart = n; // remember where Content-Length is in buffer
nixnax	142:54d1543e23e5	889	n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax	142:54d1543e23e5	890	n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax	217:86498f9ab967	891	#define SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	892	#ifdef SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	893	// if this is enabled then the maximum value of the serial port receive buffer will show up in the http headers of your browser - nice for debugging
nixnax	210:a2a651249a9a	894	n=n+sprintf(n+dataStart,"Maxbuflevel: %d\r\n", ppp.rx.maxbuflevel);
nixnax	210:a2a651249a9a	895	#endif
nixnax	142:54d1543e23e5	896	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	897	nHeader=n; // size of HTTP header
nixnax	210:a2a651249a9a	898
nixnax	142:54d1543e23e5	899	if( httpGetRoot == 0 ) {
nixnax	142:54d1543e23e5	900	// this is where we insert our web page into the buffer
nixnax	142:54d1543e23e5	901	memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax	142:54d1543e23e5	902	n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax	185:4cd8f91e9d49	903
nixnax	210:a2a651249a9a	904	} else if ( httpGet5 == 'w' ) { // "w" is a special page for websocket demo
nixnax	142:54d1543e23e5	905	memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax	142:54d1543e23e5	906	n = n + sizeof(webSocketPage)-1; // one less than size
nixnax	185:4cd8f91e9d49	907	*flags = TCP_FLAG_ACK \| TCP_FLAG_PSH; // for a websocket page we do NOT close the connection
nixnax	142:54d1543e23e5	908	} else {
nixnax	142:54d1543e23e5	909	if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax	142:54d1543e23e5	910	#define W3C_COMPLIANT_RESPONSE_NO
nixnax	142:54d1543e23e5	911	// change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax	142:54d1543e23e5	912	#ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax	142:54d1543e23e5	913	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax	146:a45f49a2b29c	914	n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax	142:54d1543e23e5	915	#else
nixnax	142:54d1543e23e5	916	if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax	167:ff8a2d8beeb1	917	n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax	142:54d1543e23e5	918	}
nixnax	142:54d1543e23e5	919	// /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax	146:a45f49a2b29c	920	n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax	142:54d1543e23e5	921	#endif
nixnax	142:54d1543e23e5	922	} else {
nixnax	142:54d1543e23e5	923	// all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax	142:54d1543e23e5	924	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax	142:54d1543e23e5	925	n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax	142:54d1543e23e5	926	}
nixnax	142:54d1543e23e5	927	}
nixnax	142:54d1543e23e5	928	#define CONTENTLENGTHSIZE 5
nixnax	142:54d1543e23e5	929	char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax	142:54d1543e23e5	930	snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax	142:54d1543e23e5	931	memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax	142:54d1543e23e5	932	return n; // total byte size of our response
nixnax	142:54d1543e23e5	933	}
nixnax	142:54d1543e23e5	934
nixnax	160:bd701ad564cb	935	/// Handle TCP data that is not an HTTP GET.
nixnax	160:bd701ad564cb	936	/// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax	160:bd701ad564cb	937	/// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax	142:54d1543e23e5	938	int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax	142:54d1543e23e5	939	{
nixnax	142:54d1543e23e5	940	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	941	if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax	160:bd701ad564cb	942	char mask [4];
nixnax	160:bd701ad564cb	943	memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax	160:bd701ad564cb	944	int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax	160:bd701ad564cb	945	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	946	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	947	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	948	memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax	160:bd701ad564cb	949	n = len; // our response size remains exactly the same length as what we received
nixnax	142:54d1543e23e5	950	} else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax	142:54d1543e23e5	951	n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax	142:54d1543e23e5	952	dataStart[1]=0; // we don't have mask bytes on
nixnax	160:bd701ad564cb	953	} else {
nixnax	184:4133f557d4d4	954	if ( len > 1 ) { // we assume a length of 1 is a keep-alive or push packet
nixnax	221:1d7c32d8256b	955	if (v1) debugPuts("TCP data received\n"); // all other tcp push packets
nixnax	184:4133f557d4d4	956	}
nixnax	163:d1b4328e9f08	957	}
nixnax	142:54d1543e23e5	958	return n; // total byte size of our response
nixnax	142:54d1543e23e5	959	}
nixnax	142:54d1543e23e5	960
nixnax	173:6774a0c851c4	961	/// dump the TCP data to the debug serial port
nixnax	173:6774a0c851c4	962	void dumpDataTCP(int outGoing)
nixnax	173:6774a0c851c4	963	{
nixnax	173:6774a0c851c4	964	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	173:6774a0c851c4	965	if (v2) {
nixnax	173:6774a0c851c4	966	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	173:6774a0c851c4	967	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	968	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax	173:6774a0c851c4	969	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	173:6774a0c851c4	970	ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
nixnax	173:6774a0c851c4	971	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	173:6774a0c851c4	972	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	173:6774a0c851c4	973	char pbuf[80]; // local print buffer
nixnax	173:6774a0c851c4	974	int n=0;
nixnax	210:a2a651249a9a	975
nixnax	173:6774a0c851c4	976	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	210:a2a651249a9a	977
nixnax	173:6774a0c851c4	978	n=n+sprintf(pbuf+n, "IP:%d ipHeader:%d tcpHeader:%d tcpData:%d\n", packetLengthIp, headerSizeIp, headerSizeTcp, tcpDataSize); // 1 for more verbose
nixnax	221:1d7c32d8256b	979	if (n>70) debugPuts("n>pbuf overflow in dumpDataTCP()\n");
nixnax	210:a2a651249a9a	980
nixnax	221:1d7c32d8256b	981	debugPuts( pbuf );
nixnax	173:6774a0c851c4	982	if (tcpDataSize > 0) {
nixnax	173:6774a0c851c4	983	ppp.tcpData[tcpDataSize]=0; // insert a null after the data so debug printf stops printing after the data
nixnax	221:1d7c32d8256b	984	debugPuts( ppp.tcpData ); // print the tcp payload data
nixnax	221:1d7c32d8256b	985	debugPuts("\n");
nixnax	173:6774a0c851c4	986	}
nixnax	221:1d7c32d8256b	987	debugPuts( "\x1b[30m" ); // VT100 color code, print black
nixnax	173:6774a0c851c4	988	}
nixnax	173:6774a0c851c4	989	#endif
nixnax	173:6774a0c851c4	990	}
nixnax	173:6774a0c851c4	991
nixnax	142:54d1543e23e5	992	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	993	/// 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	994	void tcpHandler()
nixnax	142:54d1543e23e5	995	{
nixnax	154:18b2bd92f557	996	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	154:18b2bd92f557	997	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	998	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate TCP header start
nixnax	154:18b2bd92f557	999	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	154:18b2bd92f557	1000	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	227:f87156f9ef11	1001	char * tcpDataIn = ppp.tcpStart + headerSizeTcp; // start of TCP data after TCP header
nixnax	154:18b2bd92f557	1002	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	154:18b2bd92f557	1003
nixnax	227:f87156f9ef11	1004	unsigned int seq_in = __REV(ppp.tcp->seqTcpR); // incoming sequence number
nixnax	227:f87156f9ef11	1005	unsigned int ack_in = __REV(ppp.tcp->ackTcpR); // incoming acknowledge number
nixnax	227:f87156f9ef11	1006	unsigned int ack_out = seq_in + tcpDataSize; // calculate the acknowledge based on size of received packet
nixnax	227:f87156f9ef11	1007	unsigned int seq_out = ack_in; // adopt their version of our sequence number as our sequence number
nixnax	142:54d1543e23e5	1008
nixnax	142:54d1543e23e5	1009	// first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax	173:6774a0c851c4	1010	headerSizeIp=20;
nixnax	173:6774a0c851c4	1011	ppp.ip->headerLength = headerSizeIp/4; // ip header is 20 bytes long
nixnax	173:6774a0c851c4	1012	ppp.ip->lengthR = __REV(40); // 20 ip header + 20 tcp header
nixnax	227:f87156f9ef11	1013	headerSizeTcp = 20; // shorten outgoing TCP header size to 20 bytes (no data)
nixnax	173:6774a0c851c4	1014	ppp.tcpStart = ppp.ipStart + headerSizeIp; // recalc TCP header start
nixnax	154:18b2bd92f557	1015	ppp.tcp->offset = (headerSizeTcp/4);
nixnax	173:6774a0c851c4	1016	char * tcpDataOut = ppp.tcpStart + headerSizeTcp; // start of outgoing data
nixnax	142:54d1543e23e5	1017
nixnax	142:54d1543e23e5	1018	int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax	142:54d1543e23e5	1019	int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax	160:bd701ad564cb	1020
nixnax	185:4cd8f91e9d49	1021	ppp.tcp->windowR = __REV16( 1200 ); // set tcp window size to 1200 bytes
nixnax	142:54d1543e23e5	1022
nixnax	142:54d1543e23e5	1023	// A sparse TCP flag interpreter that implements stateless TCP connections
nixnax	142:54d1543e23e5	1024
nixnax	156:163c23249731	1025	switch ( ppp.tcp->flag.All ) {
nixnax	142:54d1543e23e5	1026	case TCP_FLAG_SYN:
nixnax	142:54d1543e23e5	1027	flagsOut = TCP_FLAG_SYN \| TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax	142:54d1543e23e5	1028	seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax	142:54d1543e23e5	1029	ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1030	break;
nixnax	184:4133f557d4d4	1031	case TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1032	case TCP_FLAG_ACK \| TCP_FLAG_PSH:
nixnax	184:4133f557d4d4	1033	if ( (ppp.tcp->flag.All == TCP_FLAG_ACK) && (tcpDataSize == 0)) return; // handle zero-size ack messages by ignoring them
nixnax	142:54d1543e23e5	1034	if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax	179:ba2b2ddd0da5	1035	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // we have data, set the PSH flag
nixnax	185:4cd8f91e9d49	1036	dataLen = httpResponse(tcpDataOut, &flagsOut); // send an http response
nixnax	142:54d1543e23e5	1037	} else {
nixnax	158:841592aed956	1038	dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax	179:ba2b2ddd0da5	1039	if (dataLen > 0) flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // if we have any data set the PSH flag
nixnax	142:54d1543e23e5	1040	}
nixnax	142:54d1543e23e5	1041	break;
nixnax	142:54d1543e23e5	1042	case TCP_FLAG_FIN:
nixnax	142:54d1543e23e5	1043	case TCP_FLAG_FIN \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1044	case TCP_FLAG_FIN \| TCP_FLAG_PSH \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1045	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax	142:54d1543e23e5	1046	ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1047	break;
nixnax	142:54d1543e23e5	1048	default:
nixnax	179:ba2b2ddd0da5	1049	return; // ignore all other packets
nixnax	142:54d1543e23e5	1050	} // switch
nixnax	142:54d1543e23e5	1051
nixnax	142:54d1543e23e5	1052	// The TCP flag handling is now done
nixnax	142:54d1543e23e5	1053	// first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax	147:0f40005cbc5f	1054	swapIpAddresses(); // swap IP source and destination addresses
nixnax	149:969d98f6fb88	1055	swapIpPorts(); // swap IP source and destination ports
nixnax	142:54d1543e23e5	1056
nixnax	158:841592aed956	1057	ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	158:841592aed956	1058	ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	160:bd701ad564cb	1059
nixnax	156:163c23249731	1060	ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax	142:54d1543e23e5	1061
nixnax	159:4d1bf96a59cd	1062	// recalculate all the header sizes
nixnax	154:18b2bd92f557	1063	tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax	154:18b2bd92f557	1064	int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax	159:4d1bf96a59cd	1065	ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax	142:54d1543e23e5	1066	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	1067
nixnax	142:54d1543e23e5	1068	// the header is all set up, now do the IP and TCP checksums
nixnax	146:a45f49a2b29c	1069	IpHeaderCheckSum(); // calculate new IP header checksum
nixnax	170:3d3b2126181c	1070	checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax	159:4d1bf96a59cd	1071	ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	161:d59f778bc8ab	1072	unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax	159:4d1bf96a59cd	1073	ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	160:bd701ad564cb	1074
nixnax	170:3d3b2126181c	1075	dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax	170:3d3b2126181c	1076	dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax	173:6774a0c851c4	1077	dumpDataTCP(1); // dump outgoing TCP data before sending the frame
nixnax	226:4898247048c7	1078	#define WAIT_BEFORE_IP_SEND_NO
nixnax	226:4898247048c7	1079	#ifdef WAIT_BEFORE_IP_SEND_YES
nixnax	226:4898247048c7	1080	wait_ms(45); // 45 ms delay before sending frame
nixnax	226:4898247048c7	1081	#endif
nixnax	144:01d98cf7738e	1082	sendPppFrame(); // All preparation complete - send the TCP response
nixnax	226:4898247048c7	1083	#define DUMP_TRANSMITTED_PPP_NO
nixnax	226:4898247048c7	1084	#ifdef DUMP_TRANSMITTED_PPP_YES
nixnax	226:4898247048c7	1085	dumpPPPFrame(); // dump every transmitted ppp frame to debug port
nixnax	226:4898247048c7	1086	#endif
nixnax	142:54d1543e23e5	1087	memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax	142:54d1543e23e5	1088	}
nixnax	142:54d1543e23e5	1089
nixnax	142:54d1543e23e5	1090	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1091	void TCPpacket()
nixnax	142:54d1543e23e5	1092	{
nixnax	173:6774a0c851c4	1093	dumpHeaderIP(0); // dump incoming packet IP header
nixnax	173:6774a0c851c4	1094	dumpHeaderTCP(0); // dump incoming packet TCP header
nixnax	173:6774a0c851c4	1095	dumpDataTCP(0); // dump incoming packet data
nixnax	142:54d1543e23e5	1096	tcpHandler();
nixnax	142:54d1543e23e5	1097	}
nixnax	142:54d1543e23e5	1098
nixnax	142:54d1543e23e5	1099	/// handle the remaining IP protocols by ignoring them
nixnax	142:54d1543e23e5	1100	void otherProtocol()
nixnax	142:54d1543e23e5	1101	{
nixnax	142:54d1543e23e5	1102	debugPrintf("Other IP protocol");
nixnax	142:54d1543e23e5	1103	}
nixnax	142:54d1543e23e5	1104
nixnax	142:54d1543e23e5	1105	/// process an incoming IP packet
nixnax	142:54d1543e23e5	1106	void IPframe()
nixnax	142:54d1543e23e5	1107	{
nixnax	167:ff8a2d8beeb1	1108	int protocol = ppp.ip->protocol;
nixnax	142:54d1543e23e5	1109	switch (protocol) {
nixnax	142:54d1543e23e5	1110	case 1:
nixnax	142:54d1543e23e5	1111	ICMPpacket();
nixnax	142:54d1543e23e5	1112	break;
nixnax	142:54d1543e23e5	1113	case 2:
nixnax	142:54d1543e23e5	1114	IGMPpacket();
nixnax	142:54d1543e23e5	1115	break;
nixnax	142:54d1543e23e5	1116	case 17:
nixnax	142:54d1543e23e5	1117	UDPpacket();
nixnax	142:54d1543e23e5	1118	break;
nixnax	142:54d1543e23e5	1119	case 6:
nixnax	142:54d1543e23e5	1120	TCPpacket();
nixnax	142:54d1543e23e5	1121	break;
nixnax	142:54d1543e23e5	1122	default:
nixnax	142:54d1543e23e5	1123	otherProtocol();
nixnax	142:54d1543e23e5	1124	}
nixnax	142:54d1543e23e5	1125	}
nixnax	142:54d1543e23e5	1126
nixnax	227:f87156f9ef11	1127	/// process LCP packets
nixnax	142:54d1543e23e5	1128	void LCPframe()
nixnax	142:54d1543e23e5	1129	{
nixnax	175:b4e6f8a6fe00	1130	int code = ppp.lcp->code;
nixnax	142:54d1543e23e5	1131	switch (code) {
nixnax	227:f87156f9ef11	1132	case 1: // LCP configuration request
nixnax	227:f87156f9ef11	1133	debugPrintf("LCP Config");
nixnax	227:f87156f9ef11	1134	if ( __REV16( ppp.lcp->lengthR ) == 4 ) {
nixnax	227:f87156f9ef11	1135	debugPrintf("LCP Ack\n");
nixnax	227:f87156f9ef11	1136	ppp.lcp->code=2; // acknowledge zero configuration request
nixnax	227:f87156f9ef11	1137	sendPppFrame();
nixnax	227:f87156f9ef11	1138	ppp.lcp->code=1; // request no options
nixnax	227:f87156f9ef11	1139	sendPppFrame();
nixnax	227:f87156f9ef11	1140	} else {
nixnax	227:f87156f9ef11	1141	debugPrintf("LCP request reject\n");
nixnax	227:f87156f9ef11	1142	ppp.lcp->code=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax	227:f87156f9ef11	1143	sendPppFrame();
nixnax	227:f87156f9ef11	1144	}
nixnax	227:f87156f9ef11	1145	break;
nixnax	227:f87156f9ef11	1146	case 2: // LCP configuration acknowledge
nixnax	227:f87156f9ef11	1147	debugPrintf("LCP Ack\n"); // don't do anything, i.e. ignore
nixnax	227:f87156f9ef11	1148	break;
nixnax	227:f87156f9ef11	1149	case 5: // LCP end
nixnax	227:f87156f9ef11	1150	ppp.lcp->code=6; // acknowledge
nixnax	227:f87156f9ef11	1151	sendPppFrame(); // acknowledge
nixnax	227:f87156f9ef11	1152	ppp.online=0; // start hunting for connect string again
nixnax	227:f87156f9ef11	1153	pppInitStruct(); // flush the receive buffer
nixnax	227:f87156f9ef11	1154	debugPrintf("LCP End (Disconnect from host)\n");
nixnax	142:54d1543e23e5	1155	break; // end connection
nixnax	142:54d1543e23e5	1156	default:
nixnax	227:f87156f9ef11	1157	debugPrintf("LCP Other\n");
nixnax	142:54d1543e23e5	1158	}
nixnax	142:54d1543e23e5	1159	}
nixnax	142:54d1543e23e5	1160
nixnax	142:54d1543e23e5	1161	/// discard packets that are not IP, IPCP, or LCP
nixnax	142:54d1543e23e5	1162	void discardedFrame()
nixnax	142:54d1543e23e5	1163	{
nixnax	142:54d1543e23e5	1164	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	1165	}
nixnax	142:54d1543e23e5	1166
nixnax	142:54d1543e23e5	1167	/// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax	142:54d1543e23e5	1168	void determinePacketType()
nixnax	142:54d1543e23e5	1169	{
nixnax	167:ff8a2d8beeb1	1170	if ( ppp.ppp->address != 0xff ) {
nixnax	167:ff8a2d8beeb1	1171	debugPrintf("Unexpected: PPP address != ff\n");
nixnax	142:54d1543e23e5	1172	return;
nixnax	142:54d1543e23e5	1173	}
nixnax	167:ff8a2d8beeb1	1174	if ( ppp.ppp->control != 3 ) {
nixnax	167:ff8a2d8beeb1	1175	debugPrintf("Unexpected: PPP control != 3\n");
nixnax	142:54d1543e23e5	1176	return;
nixnax	142:54d1543e23e5	1177	}
nixnax	167:ff8a2d8beeb1	1178	unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax	167:ff8a2d8beeb1	1179	switch ( protocol ) {
nixnax	167:ff8a2d8beeb1	1180	case 0xc021:
nixnax	142:54d1543e23e5	1181	LCPframe();
nixnax	142:54d1543e23e5	1182	break; // link control
nixnax	167:ff8a2d8beeb1	1183	case 0x8021:
nixnax	142:54d1543e23e5	1184	IPCPframe();
nixnax	142:54d1543e23e5	1185	break; // IP control
nixnax	167:ff8a2d8beeb1	1186	case 0x0021:
nixnax	142:54d1543e23e5	1187	IPframe();
nixnax	142:54d1543e23e5	1188	break; // IP itself
nixnax	142:54d1543e23e5	1189	default:
nixnax	142:54d1543e23e5	1190	discardedFrame();
nixnax	142:54d1543e23e5	1191	}
nixnax	142:54d1543e23e5	1192	}
nixnax	142:54d1543e23e5	1193
nixnax	146:a45f49a2b29c	1194	/// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax	146:a45f49a2b29c	1195	void sniff()
nixnax	146:a45f49a2b29c	1196	{
nixnax	221:1d7c32d8256b	1197	if ( pc.readable() ) debugPuts( "Sniff - Char available!\n" ); // if this prints anything it means there is a character in the serial receive buffer
nixnax	146:a45f49a2b29c	1198	}
nixnax	146:a45f49a2b29c	1199
nixnax	142:54d1543e23e5	1200	/// scan the PPP serial input stream for frame start markers
nixnax	143:c5019f856a56	1201	void waitForPppFrame()
nixnax	142:54d1543e23e5	1202	{
nixnax	142:54d1543e23e5	1203	while(1) {
nixnax	142:54d1543e23e5	1204	if ( ppp.rx.head != ppp.rx.tail ) {
nixnax	142:54d1543e23e5	1205	int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax	142:54d1543e23e5	1206	int rx = pc_getBuf(); // get the character
nixnax	142:54d1543e23e5	1207	if (rx==FRAME_7E) {
nixnax	142:54d1543e23e5	1208	if (ppp.firstFrame) { // is this the start of the first frame start
nixnax	142:54d1543e23e5	1209	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1210	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax	181:bcfe7fe2142d	1211	ppp.firstFrame=0; // clear first frame flag
nixnax	142:54d1543e23e5	1212	} else {
nixnax	142:54d1543e23e5	1213	ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax	142:54d1543e23e5	1214	processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax	142:54d1543e23e5	1215	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1216	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax	142:54d1543e23e5	1217	break;
nixnax	142:54d1543e23e5	1218	}
nixnax	142:54d1543e23e5	1219	}
nixnax	142:54d1543e23e5	1220	}
nixnax	210:a2a651249a9a	1221	// change below to YES to enable the serial to UDP demo
nixnax	210:a2a651249a9a	1222	#define SERIAL_TO_UDP_NO
nixnax	210:a2a651249a9a	1223	#ifdef SERIAL_TO_UDP_YES
nixnax	210:a2a651249a9a	1224	sendUdpData(); // demo that sends characters received on the DEBUG serial port via UDP to another host
nixnax	210:a2a651249a9a	1225	#endif
nixnax	142:54d1543e23e5	1226	}
nixnax	142:54d1543e23e5	1227	}
nixnax	142:54d1543e23e5	1228
nixnax	209:aa514cd631ee	1229	/// Wait for a dial-up modem connect command ("CLIENT") from the host PC, if found, we set ppp.online to true, which starts the IP packet scanner.
nixnax	209:aa514cd631ee	1230	// Note: a 0x7E in the input stream (ppp start of frame character) will also set ppp.online to true - see the code in pppReceiveHandler()
nixnax	153:7993def8663f	1231	void waitForPcConnectString()
nixnax	142:54d1543e23e5	1232	{
nixnax	142:54d1543e23e5	1233	while(ppp.online == 0) {
nixnax	142:54d1543e23e5	1234	// search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax	142:54d1543e23e5	1235	char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax	142:54d1543e23e5	1236	if (found1 != NULL) {
nixnax	209:aa514cd631ee	1237	if (v0) debugPrintf("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax	208:73086736610a	1238	// respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax	142:54d1543e23e5	1239	pc.puts("CLIENTSERVER");
nixnax	142:54d1543e23e5	1240	ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax	142:54d1543e23e5	1241	}
nixnax	142:54d1543e23e5	1242	}
nixnax	142:54d1543e23e5	1243	}
nixnax	142:54d1543e23e5	1244
nixnax	144:01d98cf7738e	1245	/// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax	144:01d98cf7738e	1246	void initializePpp()
nixnax	142:54d1543e23e5	1247	{
nixnax	210:a2a651249a9a	1248	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	144:01d98cf7738e	1249	debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax	227:f87156f9ef11	1250	debugPrintf("\x1b[2J\x1b[H\x1b[30m"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
nixnax	184:4133f557d4d4	1251	wait_ms(200); // a brief wait so a human can see the reset event
nixnax	227:f87156f9ef11	1252	debugPrintf("mbed PPP-Blinky HTTP & WebSocket server ready :)\n");
nixnax	210:a2a651249a9a	1253	#endif
nixnax	179:ba2b2ddd0da5	1254	pppInitStruct(); // initialize all the variables/properties/buffers
nixnax	179:ba2b2ddd0da5	1255	pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
nixnax	179:ba2b2ddd0da5	1256	pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
nixnax	143:c5019f856a56	1257	}

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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.