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@249:9ff0e20325f7, 2018-12-25 (annotated)

Committer:: nixnax
Date:: Tue Dec 25 17:32:07 2018 +0000
Revision:: 249:9ff0e20325f7
Parent:: 248:5aca1c98fc24
Child:: 250:35a3a19dc184

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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	249:9ff0e20325f7	18	// https://en.wikipedia.org/wiki/Favicon (see also html5 <link> tag)
nixnax	142:54d1543e23e5	19
nixnax	142:54d1543e23e5	20	// Handy tools
nixnax	142:54d1543e23e5	21	// 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	22	// https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax	142:54d1543e23e5	23	// http://pingtester.net/ - nice tool for high rate ping testing
nixnax	142:54d1543e23e5	24	// 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	25	// https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax	142:54d1543e23e5	26	// https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax	142:54d1543e23e5	27	// 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	28
nixnax	142:54d1543e23e5	29	// Connecting PPP-Blinky to Linux
nixnax	142:54d1543e23e5	30	// PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax	142:54d1543e23e5	31	// pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax	142:54d1543e23e5	32	// 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	33	// See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax	142:54d1543e23e5	34
nixnax	142:54d1543e23e5	35	// Special pages when PPP-Blinky is running
nixnax	142:54d1543e23e5	36	// 172.10.10.2 root page
nixnax	182:f039ec218c9f	37	// 172.10.10.2/x returns the number of ppp frames sent - this is handy for testing
nixnax	182:f039ec218c9f	38	// 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	39	// 172.10.10.2/ws a simple WebSocket demo
nixnax	182:f039ec218c9f	40	// http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle, showing cross-domain access
nixnax	207:28cd834b785d	41
nixnax	142:54d1543e23e5	42	// Ok, enough talking, time to check out some code!!
nixnax	142:54d1543e23e5	43
nixnax	142:54d1543e23e5	44	#include "ppp-blinky.h"
nixnax	142:54d1543e23e5	45
nixnax	142:54d1543e23e5	46	// The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax	146:a45f49a2b29c	47	// 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	48	// Using the second serial port will slow down packet response time
nixnax	142:54d1543e23e5	49	// Note - the LPC11U24 does NOT have a second serial port
nixnax	146:a45f49a2b29c	50
nixnax	183:6d3ba874b267	51	#define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax	142:54d1543e23e5	52
nixnax	142:54d1543e23e5	53	// here we define the OPTIONAL, second debug serial port for various mbed target boards
nixnax	142:54d1543e23e5	54	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	142:54d1543e23e5	55	#if defined(TARGET_LPC1768)
nixnax	179:ba2b2ddd0da5	56	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	57	#elif defined(TARGET_NUCLEO_F446RE) \|\| defined(TARGET_NUCLEO_L152RE) \|\| defined(TARGET_NUCLEO_L053R8) \|\| defined(TARGET_NUCLEO_L476RG) \|\| defined(TARGET_NUCLEO_F401RE)
nixnax	179:ba2b2ddd0da5	58	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	59	#elif defined(TARGET_NUCLEO_L432KC)
nixnax	196:8791e241be80	60	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	61	#elif defined(TARGET_LPC11U24)
nixnax	142:54d1543e23e5	62	#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	63	#elif defined (TARGET_KL46Z) \|\| (TARGET_KL25Z)
nixnax	179:ba2b2ddd0da5	64	RawSerial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax	193:48072570f41d	65	#elif defined(TARGET_KW41Z)
nixnax	194:5b23ebfb3626	66	RawSerial xx(PTC3, PTC2); // Second serial port on FRDM-KW41Z board
nixnax	142:54d1543e23e5	67	#elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax	142:54d1543e23e5	68	// 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	69	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	70	#else
nixnax	142:54d1543e23e5	71	#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	72	#endif
nixnax	179:ba2b2ddd0da5	73	#define debugPrintf(x...) xx.printf (x) /* if we have a serial port we can print debug messages */
nixnax	142:54d1543e23e5	74	#define debugPutc(x...) xx.putc(x)
nixnax	221:1d7c32d8256b	75	#define debugPuts(x...) xx.puts(x)
nixnax	142:54d1543e23e5	76	#define debugBaudRate(x...) xx.baud(x)
nixnax	142:54d1543e23e5	77	#else
nixnax	142:54d1543e23e5	78	// if we don't have a debug port the debug print functions do nothing
nixnax	142:54d1543e23e5	79	#define debugPrintf(x...) {}
nixnax	142:54d1543e23e5	80	#define debugPutc(x...) {}
nixnax	221:1d7c32d8256b	81	#define debugPuts(x...) {}
nixnax	142:54d1543e23e5	82	#define debugBaudRate(x...) {}
nixnax	142:54d1543e23e5	83	#endif
nixnax	142:54d1543e23e5	84
nixnax	142:54d1543e23e5	85	// verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax	182:f039ec218c9f	86	#define v0 1
nixnax	142:54d1543e23e5	87	#define v1 0
nixnax	142:54d1543e23e5	88	#define v2 0
nixnax	182:f039ec218c9f	89	#define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax	182:f039ec218c9f	90	#define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax	226:4898247048c7	91	#define DUMP_RECEIVED_PPP_FRAMES_NO /* YES to dump received PPP frames */
nixnax	142:54d1543e23e5	92
nixnax	226:4898247048c7	93	// below is the webpage we serve when we get an HTTP request to root (/)
nixnax	226:4898247048c7	94	// keep size under ~1400 bytes to fit into a single PPP packet
nixnax	249:9ff0e20325f7	95	// the <link rel="icon" ...> tag stops browsers from asking for file favicon.ico
nixnax	142:54d1543e23e5	96
nixnax	142:54d1543e23e5	97	const static char rootWebPage[] = "\
nixnax	142:54d1543e23e5	98	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	99	<html>\
nixnax	248:5aca1c98fc24	100	<!--Comment-->\
nixnax	142:54d1543e23e5	101	<head>\
nixnax	146:a45f49a2b29c	102	<title>mbed PPP-Blinky</title>\r\n\
nixnax	248:5aca1c98fc24	103	<link rel=\"icon\" href=\"data:image/gif;base64,R0lGODlhAQABAIABAP8AAAAAACwAAAAAAQABAAACAkQBADs=\">\
nixnax	226:4898247048c7	104	<style>\
nixnax	241:dece92cb7296	105	body {font-family:sans-serif; font-size:140%; text-align:center; color:#807070;}\
nixnax	248:5aca1c98fc24	106	</style>\r\n\
nixnax	142:54d1543e23e5	107	</head>\
nixnax	226:4898247048c7	108	<body>\
nixnax	142:54d1543e23e5	109	<h1>mbed PPP-Blinky Up and Running</h1>\
nixnax	142:54d1543e23e5	110	<h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax	210:a2a651249a9a	111	<h1><a href=\"/w\">WebSocket Test</a></h1>\
nixnax	245:544cea761769	112	<h1><a href=\"/x?Parameter1=Example\">Benchmark 1</a></h1>\
nixnax	142:54d1543e23e5	113	<h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax	241:dece92cb7296	114	<h1><a href=\"http://jsfiddle.net/d26cyuh2/112/embedded/result\">JSFiddle Demo</a></h1>\
nixnax	241:dece92cb7296	115	<h1>Ping Counter 0000000000</h1>\
nixnax	241:dece92cb7296	116	</body>\
nixnax	245:544cea761769	117	</html>\r\n"; // size = 553 bytes + 1 null byte = 554 bytes
nixnax	142:54d1543e23e5	118
nixnax	167:ff8a2d8beeb1	119	// this is a websocket demo html page we serve when GET /ws is requested
nixnax	226:4898247048c7	120	// it contains some javascript to handle the websocket activities
nixnax	249:9ff0e20325f7	121	// the <link rel="icon" ...> tag stops browsers from asking for file favicon.ico
nixnax	142:54d1543e23e5	122	const static char webSocketPage[] = "\
nixnax	142:54d1543e23e5	123	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	124	<html>\
nixnax	142:54d1543e23e5	125	<head>\
nixnax	226:4898247048c7	126	<title>mbed PPP-Blinky WebSocket</title>\
nixnax	248:5aca1c98fc24	127	<link rel=\"icon\" href=\"data:image/gif;base64,R0lGODlhAQABAIABAP8AAAAAACwAAAAAAQABAAACAkQBADs=\">\
nixnax	142:54d1543e23e5	128	<script>\
nixnax	142:54d1543e23e5	129	window.onload=function(){\
nixnax	142:54d1543e23e5	130	var url=\"ws://172.10.10.2\";\
nixnax	142:54d1543e23e5	131	var sts=document.getElementById(\"sts\");\
nixnax	142:54d1543e23e5	132	var btn=document.getElementById(\"btn\");\
nixnax	142:54d1543e23e5	133	var ctr=0;\
nixnax	142:54d1543e23e5	134	function show(text){sts.textContent=text;}\
nixnax	142:54d1543e23e5	135	btn.onclick=function(){\
nixnax	142:54d1543e23e5	136	if(btn.textContent==\"Connect\"){\
nixnax	142:54d1543e23e5	137	x=new WebSocket(url);\
nixnax	142:54d1543e23e5	138	x.onopen=function(){\
nixnax	226:4898247048c7	139	show(\"Connected to PPP-Blinky WebSocket service at: \"+url);\
nixnax	142:54d1543e23e5	140	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	141	};\
nixnax	226:4898247048c7	142	x.onclose=function(){show(\"WebSocket closed\");};\
nixnax	226:4898247048c7	143	x.onmessage=function(msg){show(\"PPP-Blinky WebSocket service responded with: \\\"\"+msg.data+\"\\\"\");};\
nixnax	142:54d1543e23e5	144	} else {\
nixnax	142:54d1543e23e5	145	x.send(ctr);\
nixnax	142:54d1543e23e5	146	ctr=ctr+1;\
nixnax	142:54d1543e23e5	147	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	148	}\
nixnax	142:54d1543e23e5	149	};\
nixnax	142:54d1543e23e5	150	};\
nixnax	142:54d1543e23e5	151	</script>\
nixnax	226:4898247048c7	152	<style>\
nixnax	241:dece92cb7296	153	body {font-family:sans-serif; font-size:140%; text-align:center; color:#807070;}\
nixnax	241:dece92cb7296	154	button {font-size:140%; background-color:#7eeeee; border-radius:15px; border:none; margin-top:20px; }\
nixnax	226:4898247048c7	155	</style>\
nixnax	226:4898247048c7	156	<body>\
nixnax	226:4898247048c7	157	<h1>mbed PPP-Blinky WebSocket Test</h1>\
nixnax	226:4898247048c7	158	<h1><div id=\"sts\">Idle</div><h1>\
nixnax	226:4898247048c7	159	<button id=\"btn\">Connect</button>\
nixnax	142:54d1543e23e5	160	</body>\
nixnax	226:4898247048c7	161	</html>"; // size = 1037 bytes + 1 null byte = 1038 bytes
nixnax	142:54d1543e23e5	162
nixnax	142:54d1543e23e5	163	// 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	164	// On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax	142:54d1543e23e5	165	// The modem baud rate should be set to 115200 baud
nixnax	142:54d1543e23e5	166	// See instructions at the top.
nixnax	142:54d1543e23e5	167	// 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	168	RawSerial pc (USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax	142:54d1543e23e5	169
nixnax	142:54d1543e23e5	170	DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax	142:54d1543e23e5	171
nixnax	142:54d1543e23e5	172	pppType ppp; // our global - definitely not thread safe
nixnax	142:54d1543e23e5	173
nixnax	142:54d1543e23e5	174	/// Initialize the ppp structure and clear the receive buffer
nixnax	142:54d1543e23e5	175	void pppInitStruct()
nixnax	142:54d1543e23e5	176	{
nixnax	223:917b554cb8a5	177	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	178	ppp.online=0;
nixnax	142:54d1543e23e5	179	ppp.rx.tail=0;
nixnax	142:54d1543e23e5	180	ppp.rx.rtail=0;
nixnax	142:54d1543e23e5	181	ppp.rx.head=0;
nixnax	142:54d1543e23e5	182	ppp.rx.buflevel=0;
nixnax	209:aa514cd631ee	183	ppp.rx.maxbuflevel=0;
nixnax	221:1d7c32d8256b	184	ppp.rx.bufferfull=0;
nixnax	142:54d1543e23e5	185	ppp.pkt.len=0;
nixnax	154:18b2bd92f557	186	ppp.ipData.ident=10000; // easy to recognize in ip packet dumps
nixnax	142:54d1543e23e5	187	ppp.ledState=0;
nixnax	142:54d1543e23e5	188	ppp.hdlc.frameStartIndex=0;
nixnax	146:a45f49a2b29c	189	ppp.responseCounter=0;
nixnax	239:426e50519204	190	ppp.pingCount=0; // number of ICMP pings we have received
nixnax	142:54d1543e23e5	191	ppp.firstFrame=1;
nixnax	175:b4e6f8a6fe00	192	ppp.ppp = (pppHeaderType *)ppp.pkt.buf; // pointer to ppp header
nixnax	175:b4e6f8a6fe00	193	ppp.ip = (ipHeaderType *)(ppp.pkt.buf+4); // pointer to IP header
nixnax	142:54d1543e23e5	194	}
nixnax	142:54d1543e23e5	195
nixnax	142:54d1543e23e5	196	/// Toggle the LED on every second PPP packet received
nixnax	142:54d1543e23e5	197	void led1Toggle()
nixnax	142:54d1543e23e5	198	{
nixnax	142:54d1543e23e5	199	led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax	143:c5019f856a56	200	ppp.ledState++;
nixnax	142:54d1543e23e5	201	}
nixnax	142:54d1543e23e5	202
nixnax	179:ba2b2ddd0da5	203	/// Returns 1 after a connect message, 0 at startup or after a disconnect message
nixnax	150:3366bf3d294e	204	int connectedPpp()
nixnax	142:54d1543e23e5	205	{
nixnax	142:54d1543e23e5	206	return ppp.online;
nixnax	143:c5019f856a56	207	}
nixnax	142:54d1543e23e5	208
nixnax	179:ba2b2ddd0da5	209	/// PPP serial port receive interrupt handler.
nixnax	143:c5019f856a56	210	/// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax	143:c5019f856a56	211	/// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax	179:ba2b2ddd0da5	212	void pppReceiveHandler()
nixnax	142:54d1543e23e5	213	{
nixnax	142:54d1543e23e5	214	char ch;
nixnax	179:ba2b2ddd0da5	215	while ( pc.readable() ) {
nixnax	223:917b554cb8a5	216	int localHead = (ppp.rx.head+1); // local head index
nixnax	223:917b554cb8a5	217	if (localHead > RXBUFLEN) localHead=0; // increment and wrap head index
nixnax	223:917b554cb8a5	218	if ( localHead == ppp.rx.rtail ) {
nixnax	221:1d7c32d8256b	219	ppp.rx.bufferfull = 1; // set flag if rx buffer is full
nixnax	243:24f899297799	220	#define BUFFER_FULL_TRAP_NO
nixnax	243:24f899297799	221	#ifdef BUFFER_FULL_TRAP_YES
nixnax	243:24f899297799	222	while(1) {
nixnax	243:24f899297799	223	led1Toggle(); // flash LED at a slow rate to indicate buffer overfloe
nixnax	243:24f899297799	224	wait_ms(150);
nixnax	243:24f899297799	225	}
nixnax	243:24f899297799	226	#elseif
nixnax	221:1d7c32d8256b	227	return; // don't read if rx buffer is full
nixnax	243:24f899297799	228	#endif
nixnax	142:54d1543e23e5	229	}
nixnax	142:54d1543e23e5	230	ch = pc.getc(); // read new character
nixnax	142:54d1543e23e5	231	ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax	209:aa514cd631ee	232	if (ch == 0x7E) { // check for ppp frame start character
nixnax	209:aa514cd631ee	233	if ( ppp.online == 0 ) { // check if we are offline
nixnax	209:aa514cd631ee	234	ppp.online = 1; // if we see a frame start character we immediately change status to online
nixnax	142:54d1543e23e5	235	}
nixnax	142:54d1543e23e5	236	}
nixnax	223:917b554cb8a5	237	ppp.rx.head = localHead; // update real head pointer
nixnax	221:1d7c32d8256b	238	ppp.rx.buflevel++; // update buffer level counter
nixnax	209:aa514cd631ee	239	if ( ppp.rx.buflevel > ppp.rx.maxbuflevel ) {
nixnax	221:1d7c32d8256b	240	ppp.rx.maxbuflevel = ppp.rx.buflevel; // remember the maximum usage of rx buffer
nixnax	209:aa514cd631ee	241	}
nixnax	142:54d1543e23e5	242	}
nixnax	142:54d1543e23e5	243	}
nixnax	142:54d1543e23e5	244
nixnax	145:098b6ed2f7f2	245	/// update the cumulative PPP FCS (frame check sequence)
nixnax	226:4898247048c7	246	void fcsDo(register int x)
nixnax	142:54d1543e23e5	247	{
nixnax	230:ee097c486e45	248	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	249	x>>=1;
nixnax	230:ee097c486e45	250	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	251	x>>=1;
nixnax	230:ee097c486e45	252	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	253	x>>=1;
nixnax	230:ee097c486e45	254	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	255	x>>=1;
nixnax	230:ee097c486e45	256	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	257	x>>=1;
nixnax	230:ee097c486e45	258	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	259	x>>=1;
nixnax	230:ee097c486e45	260	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	261	x>>=1;
nixnax	230:ee097c486e45	262	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	142:54d1543e23e5	263	}
nixnax	142:54d1543e23e5	264
nixnax	145:098b6ed2f7f2	265	/// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax	145:098b6ed2f7f2	266	int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax	142:54d1543e23e5	267	{
nixnax	226:4898247048c7	268	ppp.fcs=0xffff; // fcs initial value
nixnax	145:098b6ed2f7f2	269	for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax	145:098b6ed2f7f2	270	return ppp.fcs;
nixnax	142:54d1543e23e5	271	}
nixnax	142:54d1543e23e5	272
nixnax	142:54d1543e23e5	273	/// Get one character from our received PPP buffer
nixnax	142:54d1543e23e5	274	int pc_getBuf()
nixnax	142:54d1543e23e5	275	{
nixnax	142:54d1543e23e5	276	int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax	230:ee097c486e45	277	int temptail = ppp.rx.tail+1;
nixnax	230:ee097c486e45	278	if (temptail > RXBUFLEN) temptail=0;
nixnax	142:54d1543e23e5	279	ppp.rx.buflevel--;
nixnax	230:ee097c486e45	280	ppp.rx.tail = temptail;
nixnax	142:54d1543e23e5	281	return x;
nixnax	142:54d1543e23e5	282	}
nixnax	142:54d1543e23e5	283
nixnax	142:54d1543e23e5	284	/// Dump a PPP frame to the debug serial port
nixnax	142:54d1543e23e5	285	/// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax	142:54d1543e23e5	286	/// Capture the frame's hex output in your terminal program and save as a text file
nixnax	164:c3de3d212c4b	287	/// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax	142:54d1543e23e5	288	void dumpPPPFrame()
nixnax	142:54d1543e23e5	289	{
nixnax	230:ee097c486e45	290	char pbuf[100];
nixnax	142:54d1543e23e5	291	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	210:a2a651249a9a	292
nixnax	142:54d1543e23e5	293	sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax	210:a2a651249a9a	294
nixnax	221:1d7c32d8256b	295	debugPuts(pbuf);
nixnax	142:54d1543e23e5	296	}
nixnax	210:a2a651249a9a	297
nixnax	142:54d1543e23e5	298	sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax	210:a2a651249a9a	299
nixnax	221:1d7c32d8256b	300	debugPuts(pbuf);
nixnax	142:54d1543e23e5	301	}
nixnax	142:54d1543e23e5	302
nixnax	142:54d1543e23e5	303	/// Process a received PPP frame
nixnax	142:54d1543e23e5	304	void processPPPFrame(int start, int end)
nixnax	142:54d1543e23e5	305	{
nixnax	226:4898247048c7	306	led1Toggle(); // change led1 state on received frames
nixnax	142:54d1543e23e5	307	if(start==end) {
nixnax	142:54d1543e23e5	308	return; // empty frame
nixnax	142:54d1543e23e5	309	}
nixnax	226:4898247048c7	310	ppp.fcs=0xffff; // fcs initial value
nixnax	142:54d1543e23e5	311	char * dest = ppp.pkt.buf;
nixnax	142:54d1543e23e5	312	ppp.pkt.len=0;
nixnax	142:54d1543e23e5	313	int unstuff=0;
nixnax	142:54d1543e23e5	314	int idx = start;
nixnax	142:54d1543e23e5	315	while(1) {
nixnax	142:54d1543e23e5	316	if (unstuff==0) {
nixnax	142:54d1543e23e5	317	if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax	142:54d1543e23e5	318	else {
nixnax	142:54d1543e23e5	319	*dest = ppp.rx.buf[idx];
nixnax	142:54d1543e23e5	320	ppp.pkt.len++;
nixnax	142:54d1543e23e5	321	dest++;
nixnax	145:098b6ed2f7f2	322	fcsDo(ppp.rx.buf[idx]);
nixnax	142:54d1543e23e5	323	}
nixnax	142:54d1543e23e5	324	} else { // unstuff characters prefixed with 0x7d
nixnax	142:54d1543e23e5	325	*dest = ppp.rx.buf[idx]^0x20;
nixnax	142:54d1543e23e5	326	ppp.pkt.len++;
nixnax	142:54d1543e23e5	327	dest++;
nixnax	145:098b6ed2f7f2	328	fcsDo(ppp.rx.buf[idx]^0x20);
nixnax	142:54d1543e23e5	329	unstuff=0;
nixnax	142:54d1543e23e5	330	}
nixnax	216:e3c5a5b47295	331	idx = idx+1;
nixnax	216:e3c5a5b47295	332	if (idx > RXBUFLEN) idx=0;
nixnax	142:54d1543e23e5	333	if (idx == end) break;
nixnax	142:54d1543e23e5	334	}
nixnax	145:098b6ed2f7f2	335	ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax	226:4898247048c7	336	#ifdef DUMP_RECEIVED_PPP_FRAMES_YES
nixnax	226:4898247048c7	337	dumpPPPFrame(); // hex dump ALL ppp frames to the debug port
nixnax	226:4898247048c7	338	#endif
nixnax	142:54d1543e23e5	339	if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax	142:54d1543e23e5	340	determinePacketType();
nixnax	142:54d1543e23e5	341	} else {
nixnax	142:54d1543e23e5	342	#define REPORT_FCS_ERROR_YES
nixnax	142:54d1543e23e5	343	#ifdef REPORT_FCS_ERROR_YES
nixnax	230:ee097c486e45	344	char pbuf[100]; // local print buffer
nixnax	142:54d1543e23e5	345	sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax	221:1d7c32d8256b	346	debugPuts( pbuf );
nixnax	226:4898247048c7	347	#define DUMP_PPP_FRAME_ON_ERROR_NO
nixnax	226:4898247048c7	348	#ifdef DUMP_PPP_FRAME_ON_ERROR_YES
nixnax	226:4898247048c7	349	dumpPPPFrame(); // dump frames with errors in them
nixnax	226:4898247048c7	350	#endif
nixnax	142:54d1543e23e5	351	#endif
nixnax	142:54d1543e23e5	352	}
nixnax	142:54d1543e23e5	353	}
nixnax	142:54d1543e23e5	354
nixnax	142:54d1543e23e5	355	/// do PPP HDLC-like handling of special (flag) characters
nixnax	143:c5019f856a56	356	void hdlcPut(int ch)
nixnax	142:54d1543e23e5	357	{
nixnax	247:7b0a8e6fbb86	358	if ( (ch<0x20) \|\| (ch==0x7d) \|\| (ch==0x7e) \|\| (ch>0x7f) ) {
nixnax	226:4898247048c7	359	pc.putc(0x7d);
nixnax	226:4898247048c7	360	pc.putc(ch^0x20); // these characters need special handling
nixnax	142:54d1543e23e5	361	} else {
nixnax	226:4898247048c7	362	pc.putc(ch);
nixnax	142:54d1543e23e5	363	}
nixnax	142:54d1543e23e5	364	}
nixnax	142:54d1543e23e5	365
nixnax	142:54d1543e23e5	366	/// send a PPP frame in HDLC format
nixnax	144:01d98cf7738e	367	void sendPppFrame()
nixnax	143:c5019f856a56	368	{
nixnax	172:449dd7a28955	369	ppp.responseCounter++; // count the number of ppp frames we send
nixnax	145:098b6ed2f7f2	370	int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax	142:54d1543e23e5	371	ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax	142:54d1543e23e5	372	ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax	226:4898247048c7	373	pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax	142:54d1543e23e5	374	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	226:4898247048c7	375	// wait_us(86); // wait one character time
nixnax	210:a2a651249a9a	376
nixnax	142:54d1543e23e5	377	hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax	142:54d1543e23e5	378	}
nixnax	226:4898247048c7	379	pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax	142:54d1543e23e5	380	}
nixnax	142:54d1543e23e5	381
nixnax	143:c5019f856a56	382	/// convert a network ip address in the buffer to an integer (IP adresses are big-endian, i.e most significant byte first)
nixnax	143:c5019f856a56	383	int bufferToIP(char * buffer)
nixnax	143:c5019f856a56	384	{
nixnax	143:c5019f856a56	385	int result=0;
nixnax	143:c5019f856a56	386	for(int i=0; i<4; i++) result = (result<<8)\|(*buffer++ & 0xff);
nixnax	143:c5019f856a56	387	return result;
nixnax	143:c5019f856a56	388	}
nixnax	143:c5019f856a56	389
nixnax	177:dab9e685af53	390	/// convert 4-byte ip address to 32-bit
nixnax	228:7fb878500862	391	unsigned int integersToIp( int a, int b, int c, int d)
nixnax	179:ba2b2ddd0da5	392	{
nixnax	177:dab9e685af53	393	return a<<24 \| b<<16 \| c<<8 \| d;
nixnax	177:dab9e685af53	394	}
nixnax	177:dab9e685af53	395
nixnax	142:54d1543e23e5	396	/// handle IPCP configuration requests
nixnax	142:54d1543e23e5	397	void ipcpConfigRequestHandler()
nixnax	142:54d1543e23e5	398	{
nixnax	230:ee097c486e45	399	debugPuts("Their IPCP Config Req, Our Ack\n");
nixnax	173:6774a0c851c4	400	if(ppp.ipcp->request[0]==3) {
nixnax	143:c5019f856a56	401	ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax	173:6774a0c851c4	402	debugPrintf("Host IP = %d.%d.%d.%d (%08x)\n", ppp.ipcp->request[2],ppp.ipcp->request[3],ppp.ipcp->request[4],ppp.ipcp->request[5],ppp.hostIP);
nixnax	143:c5019f856a56	403	}
nixnax	143:c5019f856a56	404
nixnax	167:ff8a2d8beeb1	405	ppp.ipcp->code=2; // change code to ack
nixnax	144:01d98cf7738e	406	sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax	142:54d1543e23e5	407
nixnax	230:ee097c486e45	408	debugPuts("Our IPCP Ask (no options)\n");
nixnax	167:ff8a2d8beeb1	409	ppp.ipcp->code=1; // change code to request
nixnax	167:ff8a2d8beeb1	410	ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax	167:ff8a2d8beeb1	411	ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax	144:01d98cf7738e	412	sendPppFrame(); // send our request
nixnax	142:54d1543e23e5	413	}
nixnax	142:54d1543e23e5	414
nixnax	142:54d1543e23e5	415	/// handle IPCP acknowledge (do nothing)
nixnax	142:54d1543e23e5	416	void ipcpAckHandler()
nixnax	142:54d1543e23e5	417	{
nixnax	230:ee097c486e45	418	debugPuts("Their IPCP Grant\n");
nixnax	142:54d1543e23e5	419	}
nixnax	142:54d1543e23e5	420
nixnax	143:c5019f856a56	421	/// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax	143:c5019f856a56	422	/// This is how Linux responds to an IPCP request with no options - Windows assumes any IP address on the submnet is OK.
nixnax	142:54d1543e23e5	423	void ipcpNackHandler()
nixnax	142:54d1543e23e5	424	{
nixnax	230:ee097c486e45	425	debugPuts("Their IPCP Nack\n");
nixnax	173:6774a0c851c4	426	if (ppp.ipcp->request[0]==3) { // check if the NACK contains an IP address parameter
nixnax	167:ff8a2d8beeb1	427	ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax	144:01d98cf7738e	428	sendPppFrame(); // let's request this IP address as ours
nixnax	230:ee097c486e45	429	debugPuts("Our IPCP ACK (received an IP)\n");
nixnax	146:a45f49a2b29c	430	} else { // if it's not an IP nack we ignore it
nixnax	230:ee097c486e45	431	debugPuts("IPCP Nack Ignored\n");
nixnax	146:a45f49a2b29c	432	}
nixnax	142:54d1543e23e5	433	}
nixnax	142:54d1543e23e5	434
nixnax	142:54d1543e23e5	435	/// handle all other IPCP requests (by ignoring them)
nixnax	142:54d1543e23e5	436	void ipcpDefaultHandler()
nixnax	142:54d1543e23e5	437	{
nixnax	230:ee097c486e45	438	debugPuts("Their IPCP Other\n");
nixnax	142:54d1543e23e5	439	}
nixnax	142:54d1543e23e5	440
nixnax	142:54d1543e23e5	441	/// process an incoming IPCP packet
nixnax	142:54d1543e23e5	442	void IPCPframe()
nixnax	142:54d1543e23e5	443	{
nixnax	167:ff8a2d8beeb1	444	int action = ppp.ipcp->code; // packet type is here
nixnax	167:ff8a2d8beeb1	445	switch (action) {
nixnax	142:54d1543e23e5	446	case 1:
nixnax	142:54d1543e23e5	447	ipcpConfigRequestHandler();
nixnax	142:54d1543e23e5	448	break;
nixnax	142:54d1543e23e5	449	case 2:
nixnax	142:54d1543e23e5	450	ipcpAckHandler();
nixnax	142:54d1543e23e5	451	break;
nixnax	142:54d1543e23e5	452	case 3:
nixnax	142:54d1543e23e5	453	ipcpNackHandler();
nixnax	142:54d1543e23e5	454	break;
nixnax	142:54d1543e23e5	455	default:
nixnax	142:54d1543e23e5	456	ipcpDefaultHandler();
nixnax	142:54d1543e23e5	457	}
nixnax	142:54d1543e23e5	458	}
nixnax	142:54d1543e23e5	459
nixnax	142:54d1543e23e5	460	/// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax	161:d59f778bc8ab	461	unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax	142:54d1543e23e5	462	{
nixnax	159:4d1bf96a59cd	463	unsigned int i,hi,lo;
nixnax	142:54d1543e23e5	464	unsigned char placeHolder;
nixnax	161:d59f778bc8ab	465	if (restart) ppp.sum=0;
nixnax	142:54d1543e23e5	466	if (len&1) {
nixnax	142:54d1543e23e5	467	placeHolder = ptr[len];
nixnax	142:54d1543e23e5	468	ptr[len]=0; // if the byte count is odd, insert one extra zero byte is after the last real byte because we sum byte PAIRS
nixnax	142:54d1543e23e5	469	}
nixnax	142:54d1543e23e5	470	i=0;
nixnax	142:54d1543e23e5	471	while ( i<len ) {
nixnax	210:a2a651249a9a	472
nixnax	142:54d1543e23e5	473	hi = ptr[i++];
nixnax	142:54d1543e23e5	474	lo = ptr[i++];
nixnax	159:4d1bf96a59cd	475	ppp.sum = ppp.sum + ((hi<<8)\|lo);
nixnax	142:54d1543e23e5	476	}
nixnax	142:54d1543e23e5	477	if (len&1) {
nixnax	142:54d1543e23e5	478	ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax	142:54d1543e23e5	479	}
nixnax	159:4d1bf96a59cd	480	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax	159:4d1bf96a59cd	481	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax	159:4d1bf96a59cd	482	return ~ppp.sum;
nixnax	142:54d1543e23e5	483	}
nixnax	142:54d1543e23e5	484
nixnax	142:54d1543e23e5	485	/// perform the checksum on an IP header
nixnax	146:a45f49a2b29c	486	void IpHeaderCheckSum()
nixnax	142:54d1543e23e5	487	{
nixnax	161:d59f778bc8ab	488	ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax	161:d59f778bc8ab	489	int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax	161:d59f778bc8ab	490	unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax	161:d59f778bc8ab	491	ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax	146:a45f49a2b29c	492	}
nixnax	146:a45f49a2b29c	493
nixnax	147:0f40005cbc5f	494	/// swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	495	void swapIpAddresses()
nixnax	147:0f40005cbc5f	496	{
nixnax	162:594729c0e5c1	497	unsigned int tempHold;
nixnax	162:594729c0e5c1	498	tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax	162:594729c0e5c1	499	ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax	162:594729c0e5c1	500	ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax	147:0f40005cbc5f	501	}
nixnax	147:0f40005cbc5f	502
nixnax	149:969d98f6fb88	503	/// swap the IP source and destination ports
nixnax	149:969d98f6fb88	504	void swapIpPorts()
nixnax	149:969d98f6fb88	505	{
nixnax	173:6774a0c851c4	506	int headerSizeIP = 4 * (ppp.ip->headerLength); // calculate size of IP header
nixnax	173:6774a0c851c4	507	char * ipSrcPort = ppp.ipStart + headerSizeIP + 0; // ip source port location
nixnax	173:6774a0c851c4	508	char * ipDstPort = ppp.ipStart + headerSizeIP + 2; // ip destin port location
nixnax	149:969d98f6fb88	509	char tempHold[2];
nixnax	149:969d98f6fb88	510	memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax	149:969d98f6fb88	511	memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax	149:969d98f6fb88	512	memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax	149:969d98f6fb88	513	}
nixnax	149:969d98f6fb88	514
nixnax	170:3d3b2126181c	515	/// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax	170:3d3b2126181c	516	void checkSumPseudoHeader( unsigned int packetLength )
nixnax	170:3d3b2126181c	517	{
nixnax	170:3d3b2126181c	518	// this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax	170:3d3b2126181c	519	pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax	170:3d3b2126181c	520	pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax	170:3d3b2126181c	521	pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax	170:3d3b2126181c	522	pseudoHeader.zero = 0; // zero byte
nixnax	170:3d3b2126181c	523	pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax	170:3d3b2126181c	524	pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax	170:3d3b2126181c	525	dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax	170:3d3b2126181c	526	}
nixnax	170:3d3b2126181c	527
nixnax	171:46b36d4edd1d	528	/// initialize an IP packet to send
nixnax	171:46b36d4edd1d	529	void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax	171:46b36d4edd1d	530	{
nixnax	171:46b36d4edd1d	531	ppp.ppp->address = 0xff;
nixnax	171:46b36d4edd1d	532	ppp.ppp->control = 3;
nixnax	171:46b36d4edd1d	533	ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax	171:46b36d4edd1d	534	ppp.ip->version = 4;
nixnax	171:46b36d4edd1d	535	ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax	171:46b36d4edd1d	536	ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax	171:46b36d4edd1d	537	ppp.ip->dontFragment=1;
nixnax	171:46b36d4edd1d	538	ppp.ip->ttl=128;
nixnax	171:46b36d4edd1d	539	ppp.ip->protocol = protocol; // udp
nixnax	171:46b36d4edd1d	540	ppp.ip->srcAdrR = __REV(srcIp);
nixnax	171:46b36d4edd1d	541	ppp.ip->dstAdrR = __REV(dstIp);
nixnax	171:46b36d4edd1d	542	ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax	171:46b36d4edd1d	543	ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax	171:46b36d4edd1d	544	ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax	171:46b36d4edd1d	545	}
nixnax	171:46b36d4edd1d	546
nixnax	171:46b36d4edd1d	547
nixnax	171:46b36d4edd1d	548	/// Build a UDP packet from scratch
nixnax	171:46b36d4edd1d	549	void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax	171:46b36d4edd1d	550	{
nixnax	171:46b36d4edd1d	551	struct {
nixnax	171:46b36d4edd1d	552	unsigned int ipAll; // length of entire ip packet
nixnax	171:46b36d4edd1d	553	unsigned int ipHeader; // length of ip header
nixnax	171:46b36d4edd1d	554	unsigned int udpAll; // length of entire udp packet
nixnax	171:46b36d4edd1d	555	unsigned int udpData; // length of udp data segment
nixnax	171:46b36d4edd1d	556	} len;
nixnax	171:46b36d4edd1d	557	len.ipHeader = 20; // ip header length
nixnax	171:46b36d4edd1d	558	len.udpData = msgLen; // udp data size
nixnax	171:46b36d4edd1d	559	len.udpAll = len.udpData+8; // update local udp packet length
nixnax	171:46b36d4edd1d	560	len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax	171:46b36d4edd1d	561	initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax	171:46b36d4edd1d	562	ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax	171:46b36d4edd1d	563	ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax	171:46b36d4edd1d	564	memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax	171:46b36d4edd1d	565	ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax	171:46b36d4edd1d	566	ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	567	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	568	checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	569	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	570	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	571	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	572	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	573	}
nixnax	171:46b36d4edd1d	574
nixnax	146:a45f49a2b29c	575	/// Process an incoming UDP packet.
nixnax	146:a45f49a2b29c	576	/// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax	146:a45f49a2b29c	577	void UDPpacket()
nixnax	146:a45f49a2b29c	578	{
nixnax	163:d1b4328e9f08	579	struct {
nixnax	163:d1b4328e9f08	580	unsigned int all; // length of entire ip packet
nixnax	163:d1b4328e9f08	581	unsigned int header; // length of ip header
nixnax	163:d1b4328e9f08	582	} ipLength;
nixnax	163:d1b4328e9f08	583
nixnax	163:d1b4328e9f08	584	struct {
nixnax	165:c47826d07e0d	585	unsigned int all; // length of entire udp packet
nixnax	163:d1b4328e9f08	586	unsigned int data; // length of udp data segment
nixnax	163:d1b4328e9f08	587	} udpLength;
nixnax	163:d1b4328e9f08	588
nixnax	163:d1b4328e9f08	589	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	163:d1b4328e9f08	590	ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	171:46b36d4edd1d	591	udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax	163:d1b4328e9f08	592	udpLength.data = udpLength.all - 8; // size of udp data
nixnax	147:0f40005cbc5f	593
nixnax	146:a45f49a2b29c	594	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	171:46b36d4edd1d	595	char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax	171:46b36d4edd1d	596	char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax	163:d1b4328e9f08	597
nixnax	171:46b36d4edd1d	598	unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax	171:46b36d4edd1d	599	unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax	163:d1b4328e9f08	600
nixnax	163:d1b4328e9f08	601	if(v0) {
nixnax	163:d1b4328e9f08	602	debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax	163:d1b4328e9f08	603	debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax	163:d1b4328e9f08	604	debugPrintf("Len %03d", udpLength);
nixnax	163:d1b4328e9f08	605	}
nixnax	146:a45f49a2b29c	606	if (v1) {
nixnax	163:d1b4328e9f08	607	int printSize = udpLength.data;
nixnax	146:a45f49a2b29c	608	if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax	146:a45f49a2b29c	609	for (int i=0; i<printSize; i++) {
nixnax	163:d1b4328e9f08	610	char ch = ppp.udp->data[i];
nixnax	146:a45f49a2b29c	611	if (ch>31 && ch<127) {
nixnax	146:a45f49a2b29c	612	debugPrintf("%c", ch);
nixnax	146:a45f49a2b29c	613	} else {
nixnax	230:ee097c486e45	614	debugPuts("_");
nixnax	146:a45f49a2b29c	615	}
nixnax	146:a45f49a2b29c	616	}
nixnax	146:a45f49a2b29c	617	}
nixnax	230:ee097c486e45	618	if (v0) debugPuts("\n");
nixnax	146:a45f49a2b29c	619	#endif
nixnax	163:d1b4328e9f08	620	int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax	163:d1b4328e9f08	621	int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax	146:a45f49a2b29c	622	if ( (echoFound) \|\| (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax	146:a45f49a2b29c	623	if (echoFound) {
nixnax	171:46b36d4edd1d	624	swapIpAddresses(); // swap IP source and destination
nixnax	171:46b36d4edd1d	625	swapIpPorts(); // swap IP source and destination ports
nixnax	163:d1b4328e9f08	626	memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax	170:3d3b2126181c	627	int n=0;
nixnax	230:ee097c486e45	628	#define IDENTIFY_UDP_SERVER_NO
nixnax	230:ee097c486e45	629	#ifdef IDENTIFY_UDP_SERVER_YES
nixnax	170:3d3b2126181c	630	n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax	230:ee097c486e45	631	#endif
nixnax	168:c77eb908042a	632	udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax	171:46b36d4edd1d	633	// we may have changed data length, update all the lengths
nixnax	171:46b36d4edd1d	634	udpLength.all = udpLength.data+8; // update local udp packet length
nixnax	171:46b36d4edd1d	635	ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax	171:46b36d4edd1d	636	ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax	171:46b36d4edd1d	637	ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax	171:46b36d4edd1d	638	ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	639	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	640	checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	641	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	642	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	643	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	644	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	645	} else if ( testFound ) {
nixnax	171:46b36d4edd1d	646	unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax	171:46b36d4edd1d	647	unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax	171:46b36d4edd1d	648	unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax	171:46b36d4edd1d	649	unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax	172:449dd7a28955	650	int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter);
nixnax	171:46b36d4edd1d	651	sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax	146:a45f49a2b29c	652	}
nixnax	146:a45f49a2b29c	653	}
nixnax	142:54d1543e23e5	654	}
nixnax	142:54d1543e23e5	655
nixnax	174:e5a3f16421a5	656	/// UDP demo that sends a udp packet containing a character received from the second debug serial port.
nixnax	174:e5a3f16421a5	657	/// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
nixnax	178:3f17aa0ce5ce	658	/// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
nixnax	178:3f17aa0ce5ce	659	/// See http://www.wikihow.com/Enable-IP-Routing.
nixnax	179:ba2b2ddd0da5	660	/// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
nixnax	179:ba2b2ddd0da5	661	/// The netcat UDP receive command on the remote host would be: nc -ul 12345
nixnax	174:e5a3f16421a5	662	void sendUdpData()
nixnax	174:e5a3f16421a5	663	{
nixnax	174:e5a3f16421a5	664	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	179:ba2b2ddd0da5	665	if (ppp.online) {
nixnax	179:ba2b2ddd0da5	666	if (xx.readable()) {
nixnax	179:ba2b2ddd0da5	667	char inchar = xx.getc();
nixnax	179:ba2b2ddd0da5	668	xx.putc( inchar ); // echo the received character on the debug serial port
nixnax	228:7fb878500862	669	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	670	}
nixnax	174:e5a3f16421a5	671	}
nixnax	174:e5a3f16421a5	672	#endif
nixnax	174:e5a3f16421a5	673	}
nixnax	174:e5a3f16421a5	674
nixnax	142:54d1543e23e5	675	/// handle a PING ICMP (internet control message protocol) packet
nixnax	142:54d1543e23e5	676	void ICMPpacket() // internet control message protocol
nixnax	142:54d1543e23e5	677	{
nixnax	165:c47826d07e0d	678	struct {
nixnax	165:c47826d07e0d	679	unsigned int all; // length of entire ip packet
nixnax	165:c47826d07e0d	680	unsigned int header; // length of ip header
nixnax	165:c47826d07e0d	681	} ipLength;
nixnax	165:c47826d07e0d	682	struct {
nixnax	165:c47826d07e0d	683	unsigned int all; // length of entire udp packet
nixnax	165:c47826d07e0d	684	unsigned int data; // length of udp data segment
nixnax	165:c47826d07e0d	685	} icmpLength;
nixnax	165:c47826d07e0d	686	ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax	165:c47826d07e0d	687	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	165:c47826d07e0d	688	ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	165:c47826d07e0d	689	icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax	165:c47826d07e0d	690	icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax	142:54d1543e23e5	691	#define ICMP_TYPE_PING_REQUEST 8
nixnax	165:c47826d07e0d	692	if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax	165:c47826d07e0d	693	ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax	239:426e50519204	694	ppp.pingCount++; // count how many times we get pinged
nixnax	147:0f40005cbc5f	695	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	167:ff8a2d8beeb1	696	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	697	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	165:c47826d07e0d	698	int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax	165:c47826d07e0d	699	int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax	142:54d1543e23e5	700	if(1) {
nixnax	230:ee097c486e45	701	char pbuf[100];
nixnax	210:a2a651249a9a	702
nixnax	142:54d1543e23e5	703	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	704	debugPuts( pbuf );
nixnax	210:a2a651249a9a	705
nixnax	142:54d1543e23e5	706	sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax	210:a2a651249a9a	707
nixnax	221:1d7c32d8256b	708	debugPuts( pbuf );
nixnax	142:54d1543e23e5	709	}
nixnax	142:54d1543e23e5	710	#endif
nixnax	147:0f40005cbc5f	711	swapIpAddresses(); // swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	712	IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax	142:54d1543e23e5	713	#define ICMP_TYPE_ECHO_REPLY 0
nixnax	165:c47826d07e0d	714	ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax	165:c47826d07e0d	715	ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax	165:c47826d07e0d	716	unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax	165:c47826d07e0d	717	ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax	226:4898247048c7	718	#define DUMP_ICMP_PACKETS_NO
nixnax	226:4898247048c7	719	#ifdef DUMP_ICMP_PACKETS_YES
nixnax	165:c47826d07e0d	720	int printSize = icmpLength.data; // exclude size of icmp header
nixnax	142:54d1543e23e5	721	if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax	226:4898247048c7	722	for (int i=0; i<printSize; i++) {
nixnax	226:4898247048c7	723	char ch = ppp.icmp->data[i];
nixnax	226:4898247048c7	724	if (ch>31 && ch<127) {
nixnax	226:4898247048c7	725	debugPutc(ch);
nixnax	226:4898247048c7	726	} else {
nixnax	226:4898247048c7	727	debugPutc('_'); // for non-printable characters
nixnax	142:54d1543e23e5	728	}
nixnax	142:54d1543e23e5	729	}
nixnax	226:4898247048c7	730	debugPutc('\n');
nixnax	226:4898247048c7	731	#endif
nixnax	144:01d98cf7738e	732	sendPppFrame(); // reply to the ping
nixnax	142:54d1543e23e5	733	} else {
nixnax	142:54d1543e23e5	734	if (v0) {
nixnax	165:c47826d07e0d	735	debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax	142:54d1543e23e5	736	}
nixnax	142:54d1543e23e5	737	}
nixnax	142:54d1543e23e5	738	}
nixnax	142:54d1543e23e5	739
nixnax	142:54d1543e23e5	740	/// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax	142:54d1543e23e5	741	void IGMPpacket()
nixnax	142:54d1543e23e5	742	{
nixnax	142:54d1543e23e5	743	if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax	142:54d1543e23e5	744	}
nixnax	142:54d1543e23e5	745
nixnax	142:54d1543e23e5	746	/// dump the header of an IP pakcet on the (optional) debug serial port
nixnax	142:54d1543e23e5	747	void dumpHeaderIP (int outGoing)
nixnax	142:54d1543e23e5	748	{
nixnax	142:54d1543e23e5	749	#if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	210:a2a651249a9a	750
nixnax	155:9c6a1d249e26	751	int IPv4Id = __REV16(ppp.ip->identR);
nixnax	230:ee097c486e45	752	char pbuf[100]; // local print buffer
nixnax	142:54d1543e23e5	753	int n=0;
nixnax	142:54d1543e23e5	754	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	142:54d1543e23e5	755	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	756	#define DUMP_FULL_IP_ADDRESS_YES
nixnax	142:54d1543e23e5	757	#ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax	167:ff8a2d8beeb1	758	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	759	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	142:54d1543e23e5	760	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	761	#endif
nixnax	221:1d7c32d8256b	762	debugPuts( pbuf );
nixnax	142:54d1543e23e5	763	#ifndef TCP_HEADER_DUMP_YES
nixnax	221:1d7c32d8256b	764	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	765	#endif
nixnax	142:54d1543e23e5	766	#endif
nixnax	142:54d1543e23e5	767	}
nixnax	142:54d1543e23e5	768
nixnax	142:54d1543e23e5	769	/// dump a TCP header on the optional debug serial port
nixnax	142:54d1543e23e5	770	void dumpHeaderTCP(int outGoing)
nixnax	142:54d1543e23e5	771	{
nixnax	142:54d1543e23e5	772	#if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	155:9c6a1d249e26	773	char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax	142:54d1543e23e5	774	#define PRINT_ALL_TCP_FLAGS_YES
nixnax	142:54d1543e23e5	775	#ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax	155:9c6a1d249e26	776	memset(flagString,'.', 8); // fill string with "........"
nixnax	156:163c23249731	777	if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax	156:163c23249731	778	if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax	156:163c23249731	779	if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax	156:163c23249731	780	if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax	156:163c23249731	781	if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax	156:163c23249731	782	if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax	156:163c23249731	783	if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax	156:163c23249731	784	if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax	155:9c6a1d249e26	785	flagString[8]=0; // null terminate string
nixnax	142:54d1543e23e5	786	#else
nixnax	156:163c23249731	787	if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax	156:163c23249731	788	if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax	156:163c23249731	789	if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax	156:163c23249731	790	if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax	156:163c23249731	791	if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax	155:9c6a1d249e26	792	flagString[1]=0; // null terminate string
nixnax	142:54d1543e23e5	793	#endif
nixnax	221:1d7c32d8256b	794	debugPuts( flagString );
nixnax	142:54d1543e23e5	795	#define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	142:54d1543e23e5	796	#ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	221:1d7c32d8256b	797	debugPuts("\x1b[30m\n"); // write a black color and newline after every packet
nixnax	160:bd701ad564cb	798	#else
nixnax	221:1d7c32d8256b	799	debugPuts("\x1b[30m"); // write a black color after every packet
nixnax	142:54d1543e23e5	800	#endif
nixnax	156:163c23249731	801	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	802	debugPutc('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax	142:54d1543e23e5	803	}
nixnax	142:54d1543e23e5	804	#endif
nixnax	142:54d1543e23e5	805	}
nixnax	142:54d1543e23e5	806
nixnax	143:c5019f856a56	807	/// Encode a buffer in base-64
nixnax	184:4133f557d4d4	808	const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax	142:54d1543e23e5	809	void enc64(char * in, char * out, int len)
nixnax	142:54d1543e23e5	810	{
nixnax	142:54d1543e23e5	811	int i,j,a,b,c;
nixnax	142:54d1543e23e5	812	i=0;
nixnax	142:54d1543e23e5	813	j=0;
nixnax	142:54d1543e23e5	814	while(1) {
nixnax	142:54d1543e23e5	815	if (i<len) {
nixnax	142:54d1543e23e5	816	a = in[i++];
nixnax	142:54d1543e23e5	817	out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax	142:54d1543e23e5	818	} else break;
nixnax	142:54d1543e23e5	819	if (i<len) {
nixnax	142:54d1543e23e5	820	b = in[i++];
nixnax	142:54d1543e23e5	821	out[j++] = lut[ ( (a << 4) & 0x30) \| ( (b >> 4) & 0x0f) ];
nixnax	142:54d1543e23e5	822	out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax	142:54d1543e23e5	823	} else out[j++] = '=';
nixnax	142:54d1543e23e5	824	if (i<len) {
nixnax	142:54d1543e23e5	825	c = in[i++];
nixnax	142:54d1543e23e5	826	j--;
nixnax	142:54d1543e23e5	827	out[j++] = lut[ ( (b << 2) & 0x3c) \| ( (c >> 6) & 0x03) ];
nixnax	142:54d1543e23e5	828	out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax	142:54d1543e23e5	829	} else out[j++] = '=';
nixnax	142:54d1543e23e5	830	}
nixnax	142:54d1543e23e5	831	out[j]=0;
nixnax	142:54d1543e23e5	832	}
nixnax	142:54d1543e23e5	833
nixnax	160:bd701ad564cb	834	/// Handle a request for an http websocket.
nixnax	160:bd701ad564cb	835	/// 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	836	int webSocketHandler(char * dataStart)
nixnax	142:54d1543e23e5	837	{
nixnax	142:54d1543e23e5	838	int n=0; // byte counter
nixnax	184:4133f557d4d4	839	char * key = strstr(dataStart, "Sec-WebSocket-Key:"); // search for the key in the payload
nixnax	142:54d1543e23e5	840	if (key != NULL) {
nixnax	184:4133f557d4d4	841	key = key + 18; // skip over the key ident string "Sec-WebSocket-Key:"
nixnax	221:1d7c32d8256b	842	if (v0) debugPuts("WebSocket Request\n");
nixnax	184:4133f557d4d4	843	while ( strchr(lut, *key) == NULL) key++; // skip non-valid base-64 characters (whitespace)
nixnax	184:4133f557d4d4	844	char challenge [80];
nixnax	184:4133f557d4d4	845	int i=0;
nixnax	184:4133f557d4d4	846	char * copyTo = challenge;
nixnax	184:4133f557d4d4	847	while (strchr(lut, *key) != NULL) { // copy while we see valid base-64 characters
nixnax	184:4133f557d4d4	848	if (i++ >40) break; // prevent buffer overflow
nixnax	184:4133f557d4d4	849	copyTo++ = key++; // copy next valid base-64 character
nixnax	184:4133f557d4d4	850	}
nixnax	184:4133f557d4d4	851	strcpy(copyTo,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // append websocket gui code
nixnax	226:4898247048c7	852	#define DUMP_WEBSOCKET_CHALLENGE_NO
nixnax	226:4898247048c7	853	#ifdef DUMP_WEBSOCKET_CHALLENGE_YES
nixnax	226:4898247048c7	854	debugPrintf("Challenge is %s\n", challenge); // the string we hash for the challenge
nixnax	227:f87156f9ef11	855	#endif
nixnax	142:54d1543e23e5	856	char shaOutput [20]; // sha1 output
nixnax	184:4133f557d4d4	857	sha1( shaOutput, challenge, strlen(challenge)); // hash the challenge
nixnax	142:54d1543e23e5	858	char encOut[50];
nixnax	184:4133f557d4d4	859	enc64( shaOutput, encOut, 20); // base-64 encode
nixnax	142:54d1543e23e5	860	char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax	142:54d1543e23e5	861	char * version = challenge;
nixnax	184:4133f557d4d4	862	strncpy(version, versionstring,70); // copy their version string
nixnax	142:54d1543e23e5	863	*strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax	240:d7a01533397d	864	memset(dataStart,0,500); // blank out old data before sending the websocket response header
nixnax	142:54d1543e23e5	865	n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax	142:54d1543e23e5	866	n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax	142:54d1543e23e5	867	n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax	142:54d1543e23e5	868	n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax	142:54d1543e23e5	869	n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax	142:54d1543e23e5	870	n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax	142:54d1543e23e5	871	n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax	142:54d1543e23e5	872	}
nixnax	142:54d1543e23e5	873	return n; // this response should satisfy a web browser's websocket protocol request
nixnax	142:54d1543e23e5	874	}
nixnax	142:54d1543e23e5	875
nixnax	142:54d1543e23e5	876	#define TCP_FLAG_ACK (1<<4)
nixnax	142:54d1543e23e5	877	#define TCP_FLAG_SYN (1<<1)
nixnax	142:54d1543e23e5	878	#define TCP_FLAG_PSH (1<<3)
nixnax	142:54d1543e23e5	879	#define TCP_FLAG_RST (1<<2)
nixnax	142:54d1543e23e5	880	#define TCP_FLAG_FIN (1<<0)
nixnax	142:54d1543e23e5	881
nixnax	142:54d1543e23e5	882	/// respond to an HTTP request
nixnax	185:4cd8f91e9d49	883	int httpResponse(char * dataStart, int * flags)
nixnax	142:54d1543e23e5	884	{
nixnax	142:54d1543e23e5	885	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	886	n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax	160:bd701ad564cb	887	if (n>0) return n; // if n>0 we already have a response, so return
nixnax	142:54d1543e23e5	888
nixnax	142:54d1543e23e5	889	int nHeader; // byte size of HTTP header
nixnax	142:54d1543e23e5	890	int contentLengthStart; // index where HTML starts
nixnax	142:54d1543e23e5	891	int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax	185:4cd8f91e9d49	892	*flags = TCP_FLAG_ACK \| TCP_FLAG_FIN; // the default case is that we close the connection
nixnax	142:54d1543e23e5	893
nixnax	142:54d1543e23e5	894	httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax	142:54d1543e23e5	895	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	896	httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	897	httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	898	// for example, you could try this using netcat (nc): echo "GET /x" \| nc 172.10.10.2
nixnax	210:a2a651249a9a	899	if( (httpGetRoot==0) \|\| (httpGetx==0) \|\| (httpGet5 == 'w') ) {
nixnax	229:a81c37376187	900	n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed PPP-Blinky\r\n"); // 200 OK header
nixnax	142:54d1543e23e5	901	} else {
nixnax	229:a81c37376187	902	n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed PPP-Blinky\r\n"); // 404 header
nixnax	142:54d1543e23e5	903	}
nixnax	142:54d1543e23e5	904	n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax	142:54d1543e23e5	905	contentLengthStart = n; // remember where Content-Length is in buffer
nixnax	142:54d1543e23e5	906	n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax	142:54d1543e23e5	907	n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax	217:86498f9ab967	908	#define SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	909	#ifdef SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	910	// 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	911	n=n+sprintf(n+dataStart,"Maxbuflevel: %d\r\n", ppp.rx.maxbuflevel);
nixnax	210:a2a651249a9a	912	#endif
nixnax	241:dece92cb7296	913	#define SHOWPINGCOUNT_NO
nixnax	240:d7a01533397d	914	#ifdef SHOWPINGCOUNT_YES
nixnax	241:dece92cb7296	915	// if this is enabled then the ICMP ping count will show up in the http headers of your browser - disabled for now because it's also displayed in the root page
nixnax	240:d7a01533397d	916	n=n+sprintf(n+dataStart,"PingCount: %d\r\n", ppp.pingCount);
nixnax	240:d7a01533397d	917	#endif
nixnax	142:54d1543e23e5	918	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	919	nHeader=n; // size of HTTP header
nixnax	210:a2a651249a9a	920
nixnax	142:54d1543e23e5	921	if( httpGetRoot == 0 ) {
nixnax	142:54d1543e23e5	922	// this is where we insert our web page into the buffer
nixnax	142:54d1543e23e5	923	memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax	142:54d1543e23e5	924	n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax	241:dece92cb7296	925	// naximum length of pingCount (maximum number of digits of an unsigned 32-bit int)
nixnax	241:dece92cb7296	926	#define PINGCOUNTMAXLEN (10)
nixnax	241:dece92cb7296	927	char pingCountString[PINGCOUNTMAXLEN+1]; // space for the ten digits and a string terminator 0
nixnax	241:dece92cb7296	928	snprintf(pingCountString,PINGCOUNTMAXLEN+1,"%*d",PINGCOUNTMAXLEN,ppp.pingCount); // print number of ICMP pings right justified in 10 spaces
nixnax	241:dece92cb7296	929	char * pingCountStart = strstr(dataStart,"0000000000"); // find the ten zeros in the page - this is where we must paste in the ICMP count
nixnax	241:dece92cb7296	930	if ( pingCountStart != NULL )
nixnax	241:dece92cb7296	931	memcpy(pingCountStart, pingCountString, PINGCOUNTMAXLEN); // copy ping count over the ten zeros in the page
nixnax	210:a2a651249a9a	932	} else if ( httpGet5 == 'w' ) { // "w" is a special page for websocket demo
nixnax	142:54d1543e23e5	933	memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax	142:54d1543e23e5	934	n = n + sizeof(webSocketPage)-1; // one less than size
nixnax	185:4cd8f91e9d49	935	*flags = TCP_FLAG_ACK \| TCP_FLAG_PSH; // for a websocket page we do NOT close the connection
nixnax	142:54d1543e23e5	936	} else {
nixnax	142:54d1543e23e5	937	if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax	142:54d1543e23e5	938	#define W3C_COMPLIANT_RESPONSE_NO
nixnax	142:54d1543e23e5	939	// change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax	142:54d1543e23e5	940	#ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax	142:54d1543e23e5	941	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax	248:5aca1c98fc24	942	#endif
nixnax	249:9ff0e20325f7	943	if( (ppp.pingCount & 1) == 0) // check lowest bit of ping counter and respond with red or green favicon - this stops browsers from asking for favicon.ico file
nixnax	249:9ff0e20325f7	944	n=n+sprintf(n+dataStart,"<link rel=\"icon\" id=\"red-pixel\" href=\"data:image/gif;base64,R0lGODlhAQABAIABAP8AAAAAACwAAAAAAQABAAACAkQBADs\">"); // data url containing 1 red pixel gif
nixnax	248:5aca1c98fc24	945	else
nixnax	249:9ff0e20325f7	946	n=n+sprintf(n+dataStart,"<link rel=\"icon\" id=\"grn-pixel\" href=\"data:image/gif;base64,R0lGODlhAQABAIABAAD/AAAAACwAAAAAAQABAAACAkQBADs=\">"); // data url containing 1 green pixel gif
nixnax	248:5aca1c98fc24	947	if( httpGet6 == 'b' ) // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax	248:5aca1c98fc24	948	n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax	248:5aca1c98fc24	949	// /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax	248:5aca1c98fc24	950	#ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax	146:a45f49a2b29c	951	n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax	248:5aca1c98fc24	952	#else
nixnax	146:a45f49a2b29c	953	n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax	142:54d1543e23e5	954	#endif
nixnax	248:5aca1c98fc24	955	}
nixnax	248:5aca1c98fc24	956	else {
nixnax	249:9ff0e20325f7	957	// all other requests get a Mot Found response
nixnax	142:54d1543e23e5	958	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax	142:54d1543e23e5	959	n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax	142:54d1543e23e5	960	}
nixnax	142:54d1543e23e5	961	}
nixnax	142:54d1543e23e5	962	#define CONTENTLENGTHSIZE 5
nixnax	142:54d1543e23e5	963	char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax	142:54d1543e23e5	964	snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax	142:54d1543e23e5	965	memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax	142:54d1543e23e5	966	return n; // total byte size of our response
nixnax	142:54d1543e23e5	967	}
nixnax	142:54d1543e23e5	968
nixnax	160:bd701ad564cb	969	/// Handle TCP data that is not an HTTP GET.
nixnax	160:bd701ad564cb	970	/// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax	160:bd701ad564cb	971	/// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax	142:54d1543e23e5	972	int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax	142:54d1543e23e5	973	{
nixnax	142:54d1543e23e5	974	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	975	if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax	160:bd701ad564cb	976	char mask [4];
nixnax	160:bd701ad564cb	977	memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax	160:bd701ad564cb	978	int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax	160:bd701ad564cb	979	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	980	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	981	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	982	memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax	160:bd701ad564cb	983	n = len; // our response size remains exactly the same length as what we received
nixnax	142:54d1543e23e5	984	} else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax	142:54d1543e23e5	985	n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax	142:54d1543e23e5	986	dataStart[1]=0; // we don't have mask bytes on
nixnax	160:bd701ad564cb	987	} else {
nixnax	184:4133f557d4d4	988	if ( len > 1 ) { // we assume a length of 1 is a keep-alive or push packet
nixnax	221:1d7c32d8256b	989	if (v1) debugPuts("TCP data received\n"); // all other tcp push packets
nixnax	184:4133f557d4d4	990	}
nixnax	163:d1b4328e9f08	991	}
nixnax	142:54d1543e23e5	992	return n; // total byte size of our response
nixnax	142:54d1543e23e5	993	}
nixnax	142:54d1543e23e5	994
nixnax	173:6774a0c851c4	995	/// dump the TCP data to the debug serial port
nixnax	173:6774a0c851c4	996	void dumpDataTCP(int outGoing)
nixnax	173:6774a0c851c4	997	{
nixnax	173:6774a0c851c4	998	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	173:6774a0c851c4	999	if (v2) {
nixnax	173:6774a0c851c4	1000	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	173:6774a0c851c4	1001	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	1002	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax	173:6774a0c851c4	1003	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	173:6774a0c851c4	1004	ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
nixnax	173:6774a0c851c4	1005	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	173:6774a0c851c4	1006	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	230:ee097c486e45	1007	char pbuf[100]; // local print buffer
nixnax	173:6774a0c851c4	1008	int n=0;
nixnax	210:a2a651249a9a	1009
nixnax	173:6774a0c851c4	1010	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	210:a2a651249a9a	1011
nixnax	173:6774a0c851c4	1012	n=n+sprintf(pbuf+n, "IP:%d ipHeader:%d tcpHeader:%d tcpData:%d\n", packetLengthIp, headerSizeIp, headerSizeTcp, tcpDataSize); // 1 for more verbose
nixnax	230:ee097c486e45	1013	if (n>95) debugPuts("n>pbuf overflow in dumpDataTCP()\n");
nixnax	210:a2a651249a9a	1014
nixnax	221:1d7c32d8256b	1015	debugPuts( pbuf );
nixnax	173:6774a0c851c4	1016	if (tcpDataSize > 0) {
nixnax	173:6774a0c851c4	1017	ppp.tcpData[tcpDataSize]=0; // insert a null after the data so debug printf stops printing after the data
nixnax	221:1d7c32d8256b	1018	debugPuts( ppp.tcpData ); // print the tcp payload data
nixnax	221:1d7c32d8256b	1019	debugPuts("\n");
nixnax	173:6774a0c851c4	1020	}
nixnax	221:1d7c32d8256b	1021	debugPuts( "\x1b[30m" ); // VT100 color code, print black
nixnax	173:6774a0c851c4	1022	}
nixnax	173:6774a0c851c4	1023	#endif
nixnax	173:6774a0c851c4	1024	}
nixnax	173:6774a0c851c4	1025
nixnax	142:54d1543e23e5	1026	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1027	/// 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	1028	void tcpHandler()
nixnax	142:54d1543e23e5	1029	{
nixnax	154:18b2bd92f557	1030	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	154:18b2bd92f557	1031	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	1032	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate TCP header start
nixnax	154:18b2bd92f557	1033	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	154:18b2bd92f557	1034	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	227:f87156f9ef11	1035	char * tcpDataIn = ppp.tcpStart + headerSizeTcp; // start of TCP data after TCP header
nixnax	154:18b2bd92f557	1036	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	154:18b2bd92f557	1037
nixnax	227:f87156f9ef11	1038	unsigned int seq_in = __REV(ppp.tcp->seqTcpR); // incoming sequence number
nixnax	227:f87156f9ef11	1039	unsigned int ack_in = __REV(ppp.tcp->ackTcpR); // incoming acknowledge number
nixnax	227:f87156f9ef11	1040	unsigned int ack_out = seq_in + tcpDataSize; // calculate the acknowledge based on size of received packet
nixnax	227:f87156f9ef11	1041	unsigned int seq_out = ack_in; // adopt their version of our sequence number as our sequence number
nixnax	142:54d1543e23e5	1042
nixnax	142:54d1543e23e5	1043	// first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax	173:6774a0c851c4	1044	headerSizeIp=20;
nixnax	173:6774a0c851c4	1045	ppp.ip->headerLength = headerSizeIp/4; // ip header is 20 bytes long
nixnax	173:6774a0c851c4	1046	ppp.ip->lengthR = __REV(40); // 20 ip header + 20 tcp header
nixnax	227:f87156f9ef11	1047	headerSizeTcp = 20; // shorten outgoing TCP header size to 20 bytes (no data)
nixnax	173:6774a0c851c4	1048	ppp.tcpStart = ppp.ipStart + headerSizeIp; // recalc TCP header start
nixnax	154:18b2bd92f557	1049	ppp.tcp->offset = (headerSizeTcp/4);
nixnax	173:6774a0c851c4	1050	char * tcpDataOut = ppp.tcpStart + headerSizeTcp; // start of outgoing data
nixnax	142:54d1543e23e5	1051
nixnax	142:54d1543e23e5	1052	int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax	142:54d1543e23e5	1053	int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax	160:bd701ad564cb	1054
nixnax	185:4cd8f91e9d49	1055	ppp.tcp->windowR = __REV16( 1200 ); // set tcp window size to 1200 bytes
nixnax	142:54d1543e23e5	1056
nixnax	142:54d1543e23e5	1057	// A sparse TCP flag interpreter that implements stateless TCP connections
nixnax	142:54d1543e23e5	1058
nixnax	156:163c23249731	1059	switch ( ppp.tcp->flag.All ) {
nixnax	142:54d1543e23e5	1060	case TCP_FLAG_SYN:
nixnax	142:54d1543e23e5	1061	flagsOut = TCP_FLAG_SYN \| TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax	142:54d1543e23e5	1062	seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax	142:54d1543e23e5	1063	ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1064	break;
nixnax	184:4133f557d4d4	1065	case TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1066	case TCP_FLAG_ACK \| TCP_FLAG_PSH:
nixnax	184:4133f557d4d4	1067	if ( (ppp.tcp->flag.All == TCP_FLAG_ACK) && (tcpDataSize == 0)) return; // handle zero-size ack messages by ignoring them
nixnax	142:54d1543e23e5	1068	if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax	237:796851817c26	1069	led1Toggle(); // toggle the LED one more time so we can visualize the HTTP GET
nixnax	179:ba2b2ddd0da5	1070	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // we have data, set the PSH flag
nixnax	185:4cd8f91e9d49	1071	dataLen = httpResponse(tcpDataOut, &flagsOut); // send an http response
nixnax	142:54d1543e23e5	1072	} else {
nixnax	158:841592aed956	1073	dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax	179:ba2b2ddd0da5	1074	if (dataLen > 0) flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // if we have any data set the PSH flag
nixnax	142:54d1543e23e5	1075	}
nixnax	142:54d1543e23e5	1076	break;
nixnax	142:54d1543e23e5	1077	case TCP_FLAG_FIN:
nixnax	142:54d1543e23e5	1078	case TCP_FLAG_FIN \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1079	case TCP_FLAG_FIN \| TCP_FLAG_PSH \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1080	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax	142:54d1543e23e5	1081	ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1082	break;
nixnax	142:54d1543e23e5	1083	default:
nixnax	179:ba2b2ddd0da5	1084	return; // ignore all other packets
nixnax	142:54d1543e23e5	1085	} // switch
nixnax	142:54d1543e23e5	1086
nixnax	142:54d1543e23e5	1087	// The TCP flag handling is now done
nixnax	142:54d1543e23e5	1088	// first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax	147:0f40005cbc5f	1089	swapIpAddresses(); // swap IP source and destination addresses
nixnax	149:969d98f6fb88	1090	swapIpPorts(); // swap IP source and destination ports
nixnax	142:54d1543e23e5	1091
nixnax	158:841592aed956	1092	ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	158:841592aed956	1093	ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	160:bd701ad564cb	1094
nixnax	156:163c23249731	1095	ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax	142:54d1543e23e5	1096
nixnax	159:4d1bf96a59cd	1097	// recalculate all the header sizes
nixnax	154:18b2bd92f557	1098	tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax	154:18b2bd92f557	1099	int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax	159:4d1bf96a59cd	1100	ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax	142:54d1543e23e5	1101	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	1102
nixnax	142:54d1543e23e5	1103	// the header is all set up, now do the IP and TCP checksums
nixnax	146:a45f49a2b29c	1104	IpHeaderCheckSum(); // calculate new IP header checksum
nixnax	170:3d3b2126181c	1105	checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax	159:4d1bf96a59cd	1106	ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	161:d59f778bc8ab	1107	unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax	159:4d1bf96a59cd	1108	ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	160:bd701ad564cb	1109
nixnax	170:3d3b2126181c	1110	dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax	170:3d3b2126181c	1111	dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax	173:6774a0c851c4	1112	dumpDataTCP(1); // dump outgoing TCP data before sending the frame
nixnax	226:4898247048c7	1113	#define WAIT_BEFORE_IP_SEND_NO
nixnax	226:4898247048c7	1114	#ifdef WAIT_BEFORE_IP_SEND_YES
nixnax	226:4898247048c7	1115	wait_ms(45); // 45 ms delay before sending frame
nixnax	226:4898247048c7	1116	#endif
nixnax	144:01d98cf7738e	1117	sendPppFrame(); // All preparation complete - send the TCP response
nixnax	226:4898247048c7	1118	#define DUMP_TRANSMITTED_PPP_NO
nixnax	226:4898247048c7	1119	#ifdef DUMP_TRANSMITTED_PPP_YES
nixnax	226:4898247048c7	1120	dumpPPPFrame(); // dump every transmitted ppp frame to debug port
nixnax	226:4898247048c7	1121	#endif
nixnax	142:54d1543e23e5	1122	memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax	142:54d1543e23e5	1123	}
nixnax	142:54d1543e23e5	1124
nixnax	142:54d1543e23e5	1125	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1126	void TCPpacket()
nixnax	142:54d1543e23e5	1127	{
nixnax	173:6774a0c851c4	1128	dumpHeaderIP(0); // dump incoming packet IP header
nixnax	173:6774a0c851c4	1129	dumpHeaderTCP(0); // dump incoming packet TCP header
nixnax	173:6774a0c851c4	1130	dumpDataTCP(0); // dump incoming packet data
nixnax	142:54d1543e23e5	1131	tcpHandler();
nixnax	142:54d1543e23e5	1132	}
nixnax	142:54d1543e23e5	1133
nixnax	142:54d1543e23e5	1134	/// handle the remaining IP protocols by ignoring them
nixnax	142:54d1543e23e5	1135	void otherProtocol()
nixnax	142:54d1543e23e5	1136	{
nixnax	230:ee097c486e45	1137	debugPuts("Other IP protocol");
nixnax	142:54d1543e23e5	1138	}
nixnax	142:54d1543e23e5	1139
nixnax	142:54d1543e23e5	1140	/// process an incoming IP packet
nixnax	142:54d1543e23e5	1141	void IPframe()
nixnax	142:54d1543e23e5	1142	{
nixnax	167:ff8a2d8beeb1	1143	int protocol = ppp.ip->protocol;
nixnax	142:54d1543e23e5	1144	switch (protocol) {
nixnax	142:54d1543e23e5	1145	case 1:
nixnax	142:54d1543e23e5	1146	ICMPpacket();
nixnax	142:54d1543e23e5	1147	break;
nixnax	142:54d1543e23e5	1148	case 2:
nixnax	142:54d1543e23e5	1149	IGMPpacket();
nixnax	142:54d1543e23e5	1150	break;
nixnax	142:54d1543e23e5	1151	case 17:
nixnax	142:54d1543e23e5	1152	UDPpacket();
nixnax	142:54d1543e23e5	1153	break;
nixnax	142:54d1543e23e5	1154	case 6:
nixnax	142:54d1543e23e5	1155	TCPpacket();
nixnax	142:54d1543e23e5	1156	break;
nixnax	142:54d1543e23e5	1157	default:
nixnax	142:54d1543e23e5	1158	otherProtocol();
nixnax	142:54d1543e23e5	1159	}
nixnax	142:54d1543e23e5	1160	}
nixnax	142:54d1543e23e5	1161
nixnax	227:f87156f9ef11	1162	/// process LCP packets
nixnax	142:54d1543e23e5	1163	void LCPframe()
nixnax	142:54d1543e23e5	1164	{
nixnax	175:b4e6f8a6fe00	1165	int code = ppp.lcp->code;
nixnax	142:54d1543e23e5	1166	switch (code) {
nixnax	227:f87156f9ef11	1167	case 1: // LCP configuration request
nixnax	231:6bd4523833a2	1168	debugPuts("LCP Config");
nixnax	227:f87156f9ef11	1169	if ( __REV16( ppp.lcp->lengthR ) == 4 ) {
nixnax	230:ee097c486e45	1170	debugPuts("LCP Ack\n");
nixnax	227:f87156f9ef11	1171	ppp.lcp->code=2; // acknowledge zero configuration request
nixnax	227:f87156f9ef11	1172	sendPppFrame();
nixnax	227:f87156f9ef11	1173	ppp.lcp->code=1; // request no options
nixnax	227:f87156f9ef11	1174	sendPppFrame();
nixnax	227:f87156f9ef11	1175	} else {
nixnax	230:ee097c486e45	1176	debugPuts("LCP request reject\n");
nixnax	227:f87156f9ef11	1177	ppp.lcp->code=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax	227:f87156f9ef11	1178	sendPppFrame();
nixnax	227:f87156f9ef11	1179	}
nixnax	227:f87156f9ef11	1180	break;
nixnax	227:f87156f9ef11	1181	case 2: // LCP configuration acknowledge
nixnax	230:ee097c486e45	1182	debugPuts("LCP Ack\n"); // don't do anything, i.e. ignore
nixnax	227:f87156f9ef11	1183	break;
nixnax	227:f87156f9ef11	1184	case 5: // LCP end
nixnax	227:f87156f9ef11	1185	ppp.lcp->code=6; // acknowledge
nixnax	227:f87156f9ef11	1186	sendPppFrame(); // acknowledge
nixnax	227:f87156f9ef11	1187	ppp.online=0; // start hunting for connect string again
nixnax	227:f87156f9ef11	1188	pppInitStruct(); // flush the receive buffer
nixnax	230:ee097c486e45	1189	debugPuts("LCP End (Disconnect from host)\n");
nixnax	142:54d1543e23e5	1190	break; // end connection
nixnax	142:54d1543e23e5	1191	default:
nixnax	231:6bd4523833a2	1192	debugPuts("LCP Other\n");
nixnax	142:54d1543e23e5	1193	}
nixnax	142:54d1543e23e5	1194	}
nixnax	142:54d1543e23e5	1195
nixnax	142:54d1543e23e5	1196	/// discard packets that are not IP, IPCP, or LCP
nixnax	142:54d1543e23e5	1197	void discardedFrame()
nixnax	142:54d1543e23e5	1198	{
nixnax	142:54d1543e23e5	1199	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	1200	}
nixnax	142:54d1543e23e5	1201
nixnax	142:54d1543e23e5	1202	/// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax	142:54d1543e23e5	1203	void determinePacketType()
nixnax	142:54d1543e23e5	1204	{
nixnax	167:ff8a2d8beeb1	1205	if ( ppp.ppp->address != 0xff ) {
nixnax	231:6bd4523833a2	1206	debugPuts("Unexpected: PPP address != ff\n");
nixnax	142:54d1543e23e5	1207	return;
nixnax	142:54d1543e23e5	1208	}
nixnax	167:ff8a2d8beeb1	1209	if ( ppp.ppp->control != 3 ) {
nixnax	231:6bd4523833a2	1210	debugPuts("Unexpected: PPP control != 3\n");
nixnax	142:54d1543e23e5	1211	return;
nixnax	142:54d1543e23e5	1212	}
nixnax	167:ff8a2d8beeb1	1213	unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax	167:ff8a2d8beeb1	1214	switch ( protocol ) {
nixnax	167:ff8a2d8beeb1	1215	case 0xc021:
nixnax	142:54d1543e23e5	1216	LCPframe();
nixnax	142:54d1543e23e5	1217	break; // link control
nixnax	167:ff8a2d8beeb1	1218	case 0x8021:
nixnax	142:54d1543e23e5	1219	IPCPframe();
nixnax	142:54d1543e23e5	1220	break; // IP control
nixnax	167:ff8a2d8beeb1	1221	case 0x0021:
nixnax	142:54d1543e23e5	1222	IPframe();
nixnax	142:54d1543e23e5	1223	break; // IP itself
nixnax	142:54d1543e23e5	1224	default:
nixnax	142:54d1543e23e5	1225	discardedFrame();
nixnax	142:54d1543e23e5	1226	}
nixnax	142:54d1543e23e5	1227	}
nixnax	142:54d1543e23e5	1228
nixnax	146:a45f49a2b29c	1229	/// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax	146:a45f49a2b29c	1230	void sniff()
nixnax	146:a45f49a2b29c	1231	{
nixnax	221:1d7c32d8256b	1232	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	1233	}
nixnax	146:a45f49a2b29c	1234
nixnax	142:54d1543e23e5	1235	/// scan the PPP serial input stream for frame start markers
nixnax	143:c5019f856a56	1236	void waitForPppFrame()
nixnax	142:54d1543e23e5	1237	{
nixnax	142:54d1543e23e5	1238	while(1) {
nixnax	142:54d1543e23e5	1239	if ( ppp.rx.head != ppp.rx.tail ) {
nixnax	142:54d1543e23e5	1240	int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax	142:54d1543e23e5	1241	int rx = pc_getBuf(); // get the character
nixnax	238:f39289ed5a2e	1242	if (rx==0x7e) { // check for frame start/end character 0x7e
nixnax	142:54d1543e23e5	1243	if (ppp.firstFrame) { // is this the start of the first frame start
nixnax	142:54d1543e23e5	1244	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1245	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax	181:bcfe7fe2142d	1246	ppp.firstFrame=0; // clear first frame flag
nixnax	142:54d1543e23e5	1247	} else {
nixnax	142:54d1543e23e5	1248	ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax	142:54d1543e23e5	1249	processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax	142:54d1543e23e5	1250	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1251	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax	142:54d1543e23e5	1252	break;
nixnax	142:54d1543e23e5	1253	}
nixnax	142:54d1543e23e5	1254	}
nixnax	142:54d1543e23e5	1255	}
nixnax	210:a2a651249a9a	1256	// change below to YES to enable the serial to UDP demo
nixnax	210:a2a651249a9a	1257	#define SERIAL_TO_UDP_NO
nixnax	210:a2a651249a9a	1258	#ifdef SERIAL_TO_UDP_YES
nixnax	210:a2a651249a9a	1259	sendUdpData(); // demo that sends characters received on the DEBUG serial port via UDP to another host
nixnax	210:a2a651249a9a	1260	#endif
nixnax	142:54d1543e23e5	1261	}
nixnax	142:54d1543e23e5	1262	}
nixnax	142:54d1543e23e5	1263
nixnax	209:aa514cd631ee	1264	/// 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	1265	// 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	1266	void waitForPcConnectString()
nixnax	142:54d1543e23e5	1267	{
nixnax	142:54d1543e23e5	1268	while(ppp.online == 0) {
nixnax	142:54d1543e23e5	1269	// search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax	142:54d1543e23e5	1270	char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax	142:54d1543e23e5	1271	if (found1 != NULL) {
nixnax	230:ee097c486e45	1272	if (v0) debugPuts("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax	208:73086736610a	1273	// respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax	142:54d1543e23e5	1274	pc.puts("CLIENTSERVER");
nixnax	142:54d1543e23e5	1275	ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax	142:54d1543e23e5	1276	}
nixnax	142:54d1543e23e5	1277	}
nixnax	142:54d1543e23e5	1278	}
nixnax	142:54d1543e23e5	1279
nixnax	144:01d98cf7738e	1280	/// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax	144:01d98cf7738e	1281	void initializePpp()
nixnax	142:54d1543e23e5	1282	{
nixnax	210:a2a651249a9a	1283	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	144:01d98cf7738e	1284	debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax	230:ee097c486e45	1285	debugPuts("\x1b[2J\x1b[H\x1b[30m"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
nixnax	184:4133f557d4d4	1286	wait_ms(200); // a brief wait so a human can see the reset event
nixnax	230:ee097c486e45	1287	debugPuts("mbed PPP-Blinky HTTP & WebSocket server ready :)\n");
nixnax	210:a2a651249a9a	1288	#endif
nixnax	179:ba2b2ddd0da5	1289	pppInitStruct(); // initialize all the variables/properties/buffers
nixnax	179:ba2b2ddd0da5	1290	pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
nixnax	179:ba2b2ddd0da5	1291	pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
nixnax	143:c5019f856a56	1292	}

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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.