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@241:dece92cb7296, 2018-12-03 (annotated)

Committer:: nixnax
Date:: Mon Dec 03 07:41:08 2018 +0000
Revision:: 241:dece92cb7296
Parent:: 240:d7a01533397d
Child:: 242:1e9215c09da5

Display ICMP ping count in webpage using strstr()

Who changed what in which revision?

User	Revision	Line number	New contents of line
nixnax	182:f039ec218c9f	1	// PPP-Blinky - "The Most Basic Internet Thing"
nixnax	142:54d1543e23e5	2	// A Tiny HTTP Webserver Using Windows XP/7/8/10/Linux Dial-Up Networking Over A Serial Port.
nixnax	142:54d1543e23e5	3	// Receives UDP packets and responds to ping (ICMP Echo requests)
nixnax	142:54d1543e23e5	4	// WebSocket Service - see https://en.wikipedia.org/wiki/WebSocket
nixnax	142:54d1543e23e5	5
nixnax	142:54d1543e23e5	6	// Copyright 2016/2017 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax	142:54d1543e23e5	7
nixnax	142:54d1543e23e5	8	// Notes and Instructions
nixnax	142:54d1543e23e5	9	// http://bit.ly/PPP-Blinky-Instructions
nixnax	142:54d1543e23e5	10	// http://bit.ly/win-rasdial-config
nixnax	142:54d1543e23e5	11
nixnax	201:9fcf92e9f427	12	// Important - ensure that you are using the latest mbed firmware for your specific mbed target board
nixnax	201:9fcf92e9f427	13
nixnax	142:54d1543e23e5	14	// Handy reading material
nixnax	142:54d1543e23e5	15	// https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax	142:54d1543e23e5	16	// https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax	142:54d1543e23e5	17	// http://atari.kensclassics.org/wcomlog.htm
nixnax	142:54d1543e23e5	18
nixnax	142:54d1543e23e5	19	// Handy tools
nixnax	142:54d1543e23e5	20	// https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax	142:54d1543e23e5	21	// https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax	142:54d1543e23e5	22	// http://pingtester.net/ - nice tool for high rate ping testing
nixnax	142:54d1543e23e5	23	// http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE), then custom relected-in=1, reflected-out=1
nixnax	142:54d1543e23e5	24	// https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax	142:54d1543e23e5	25	// https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax	142:54d1543e23e5	26	// Windows Powershell invoke-webrequest command - use it to stress test the webserver like this: while (1){ invoke-webrequest -uri 172.10.10.1/x }
nixnax	142:54d1543e23e5	27
nixnax	142:54d1543e23e5	28	// Connecting PPP-Blinky to Linux
nixnax	142:54d1543e23e5	29	// PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax	142:54d1543e23e5	30	// pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax	142:54d1543e23e5	31	// in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax	142:54d1543e23e5	32	// See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax	142:54d1543e23e5	33
nixnax	142:54d1543e23e5	34	// Special pages when PPP-Blinky is running
nixnax	142:54d1543e23e5	35	// 172.10.10.2 root page
nixnax	182:f039ec218c9f	36	// 172.10.10.2/x returns the number of ppp frames sent - this is handy for testing
nixnax	182:f039ec218c9f	37	// 172.10.10.2/xb also returns number of ppp frames sent, but issues a fast refresh meta command. This allows you to use your browser to benchmark page load speed
nixnax	142:54d1543e23e5	38	// 172.10.10.2/ws a simple WebSocket demo
nixnax	182:f039ec218c9f	39	// http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle, showing cross-domain access
nixnax	207:28cd834b785d	40
nixnax	142:54d1543e23e5	41	// Ok, enough talking, time to check out some code!!
nixnax	142:54d1543e23e5	42
nixnax	142:54d1543e23e5	43	#include "ppp-blinky.h"
nixnax	142:54d1543e23e5	44
nixnax	142:54d1543e23e5	45	// The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax	146:a45f49a2b29c	46	// Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor the debug output.
nixnax	142:54d1543e23e5	47	// Using the second serial port will slow down packet response time
nixnax	142:54d1543e23e5	48	// Note - the LPC11U24 does NOT have a second serial port
nixnax	146:a45f49a2b29c	49
nixnax	183:6d3ba874b267	50	#define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax	142:54d1543e23e5	51
nixnax	142:54d1543e23e5	52	// here we define the OPTIONAL, second debug serial port for various mbed target boards
nixnax	142:54d1543e23e5	53	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	142:54d1543e23e5	54	#if defined(TARGET_LPC1768)
nixnax	179:ba2b2ddd0da5	55	RawSerial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	56	#elif defined(TARGET_NUCLEO_F446RE) \|\| defined(TARGET_NUCLEO_L152RE) \|\| defined(TARGET_NUCLEO_L053R8) \|\| defined(TARGET_NUCLEO_L476RG) \|\| defined(TARGET_NUCLEO_F401RE)
nixnax	179:ba2b2ddd0da5	57	RawSerial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	196:8791e241be80	58	#elif defined(TARGET_NUCLEO_L432KC)
nixnax	196:8791e241be80	59	RawSerial xx(PA_9, PA_10); // Second serial port on NUCLEO-L432KC - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	60	#elif defined(TARGET_LPC11U24)
nixnax	142:54d1543e23e5	61	#error The LPC11U24 does not have a second serial port to use for debugging - change SERIAL_PORT_MONITOR_YES back to SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	62	#elif defined (TARGET_KL46Z) \|\| (TARGET_KL25Z)
nixnax	179:ba2b2ddd0da5	63	RawSerial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax	193:48072570f41d	64	#elif defined(TARGET_KW41Z)
nixnax	194:5b23ebfb3626	65	RawSerial xx(PTC3, PTC2); // Second serial port on FRDM-KW41Z board
nixnax	142:54d1543e23e5	66	#elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax	142:54d1543e23e5	67	// change the next line to YOUR target board's second serial port pin definition if it's not present - and if it works, please send it to me - thanks!!!
nixnax	226:4898247048c7	68	RawSerial xx(p9, p10); // change this to YOUR board's second serial port pin definition - and please send it to me if it works!!!
nixnax	142:54d1543e23e5	69	#else
nixnax	142:54d1543e23e5	70	#error Add your target board's second serial port here if you want to use debugging - or simply change SERIAL_PORT_MONITOR_YES to SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	71	#endif
nixnax	179:ba2b2ddd0da5	72	#define debugPrintf(x...) xx.printf (x) /* if we have a serial port we can print debug messages */
nixnax	142:54d1543e23e5	73	#define debugPutc(x...) xx.putc(x)
nixnax	221:1d7c32d8256b	74	#define debugPuts(x...) xx.puts(x)
nixnax	142:54d1543e23e5	75	#define debugBaudRate(x...) xx.baud(x)
nixnax	142:54d1543e23e5	76	#else
nixnax	142:54d1543e23e5	77	// if we don't have a debug port the debug print functions do nothing
nixnax	142:54d1543e23e5	78	#define debugPrintf(x...) {}
nixnax	142:54d1543e23e5	79	#define debugPutc(x...) {}
nixnax	221:1d7c32d8256b	80	#define debugPuts(x...) {}
nixnax	142:54d1543e23e5	81	#define debugBaudRate(x...) {}
nixnax	142:54d1543e23e5	82	#endif
nixnax	142:54d1543e23e5	83
nixnax	142:54d1543e23e5	84	// verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax	182:f039ec218c9f	85	#define v0 1
nixnax	142:54d1543e23e5	86	#define v1 0
nixnax	142:54d1543e23e5	87	#define v2 0
nixnax	182:f039ec218c9f	88	#define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax	182:f039ec218c9f	89	#define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax	226:4898247048c7	90	#define DUMP_RECEIVED_PPP_FRAMES_NO /* YES to dump received PPP frames */
nixnax	142:54d1543e23e5	91
nixnax	226:4898247048c7	92	// below is the webpage we serve when we get an HTTP request to root (/)
nixnax	226:4898247048c7	93	// keep size under ~1400 bytes to fit into a single PPP packet
nixnax	142:54d1543e23e5	94
nixnax	142:54d1543e23e5	95	const static char rootWebPage[] = "\
nixnax	142:54d1543e23e5	96	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	97	<html>\
nixnax	142:54d1543e23e5	98	<head>\
nixnax	146:a45f49a2b29c	99	<title>mbed PPP-Blinky</title>\r\n\
nixnax	226:4898247048c7	100	<style>\
nixnax	241:dece92cb7296	101	body {font-family:sans-serif; font-size:140%; text-align:center; color:#807070;}\
nixnax	226:4898247048c7	102	</style>\
nixnax	142:54d1543e23e5	103	</head>\
nixnax	226:4898247048c7	104	<body>\
nixnax	142:54d1543e23e5	105	<h1>mbed PPP-Blinky Up and Running</h1>\
nixnax	142:54d1543e23e5	106	<h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax	210:a2a651249a9a	107	<h1><a href=\"/w\">WebSocket Test</a></h1>\
nixnax	142:54d1543e23e5	108	<h1><a href=\"/x\">Benchmark 1</a></h1>\
nixnax	142:54d1543e23e5	109	<h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax	241:dece92cb7296	110	<h1><a href=\"http://jsfiddle.net/d26cyuh2/112/embedded/result\">JSFiddle Demo</a></h1>\
nixnax	241:dece92cb7296	111	<h1>Ping Counter 0000000000</h1>\
nixnax	241:dece92cb7296	112	</body>\
nixnax	241:dece92cb7296	113	</html>\r\n"; // size = 515 bytes + 1 null byte = 516 bytes
nixnax	142:54d1543e23e5	114
nixnax	167:ff8a2d8beeb1	115	// this is a websocket demo html page we serve when GET /ws is requested
nixnax	226:4898247048c7	116	// it contains some javascript to handle the websocket activities
nixnax	142:54d1543e23e5	117	const static char webSocketPage[] = "\
nixnax	142:54d1543e23e5	118	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	119	<html>\
nixnax	142:54d1543e23e5	120	<head>\
nixnax	226:4898247048c7	121	<title>mbed PPP-Blinky WebSocket</title>\
nixnax	142:54d1543e23e5	122	<script>\
nixnax	142:54d1543e23e5	123	window.onload=function(){\
nixnax	142:54d1543e23e5	124	var url=\"ws://172.10.10.2\";\
nixnax	142:54d1543e23e5	125	var sts=document.getElementById(\"sts\");\
nixnax	142:54d1543e23e5	126	var btn=document.getElementById(\"btn\");\
nixnax	142:54d1543e23e5	127	var ctr=0;\
nixnax	142:54d1543e23e5	128	function show(text){sts.textContent=text;}\
nixnax	142:54d1543e23e5	129	btn.onclick=function(){\
nixnax	142:54d1543e23e5	130	if(btn.textContent==\"Connect\"){\
nixnax	142:54d1543e23e5	131	x=new WebSocket(url);\
nixnax	142:54d1543e23e5	132	x.onopen=function(){\
nixnax	226:4898247048c7	133	show(\"Connected to PPP-Blinky WebSocket service at: \"+url);\
nixnax	142:54d1543e23e5	134	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	135	};\
nixnax	226:4898247048c7	136	x.onclose=function(){show(\"WebSocket closed\");};\
nixnax	226:4898247048c7	137	x.onmessage=function(msg){show(\"PPP-Blinky WebSocket service responded with: \\\"\"+msg.data+\"\\\"\");};\
nixnax	142:54d1543e23e5	138	} else {\
nixnax	142:54d1543e23e5	139	x.send(ctr);\
nixnax	142:54d1543e23e5	140	ctr=ctr+1;\
nixnax	142:54d1543e23e5	141	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	142	}\
nixnax	142:54d1543e23e5	143	};\
nixnax	142:54d1543e23e5	144	};\
nixnax	142:54d1543e23e5	145	</script>\
nixnax	226:4898247048c7	146	<style>\
nixnax	241:dece92cb7296	147	body {font-family:sans-serif; font-size:140%; text-align:center; color:#807070;}\
nixnax	241:dece92cb7296	148	button {font-size:140%; background-color:#7eeeee; border-radius:15px; border:none; margin-top:20px; }\
nixnax	226:4898247048c7	149	</style>\
nixnax	226:4898247048c7	150	<body>\
nixnax	226:4898247048c7	151	<h1>mbed PPP-Blinky WebSocket Test</h1>\
nixnax	226:4898247048c7	152	<h1><div id=\"sts\">Idle</div><h1>\
nixnax	226:4898247048c7	153	<button id=\"btn\">Connect</button>\
nixnax	142:54d1543e23e5	154	</body>\
nixnax	226:4898247048c7	155	</html>"; // size = 1037 bytes + 1 null byte = 1038 bytes
nixnax	142:54d1543e23e5	156
nixnax	142:54d1543e23e5	157	// 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	158	// On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax	142:54d1543e23e5	159	// The modem baud rate should be set to 115200 baud
nixnax	142:54d1543e23e5	160	// See instructions at the top.
nixnax	142:54d1543e23e5	161	// 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	162	RawSerial pc (USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax	142:54d1543e23e5	163
nixnax	142:54d1543e23e5	164	DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax	142:54d1543e23e5	165
nixnax	142:54d1543e23e5	166	pppType ppp; // our global - definitely not thread safe
nixnax	142:54d1543e23e5	167
nixnax	142:54d1543e23e5	168	/// Initialize the ppp structure and clear the receive buffer
nixnax	142:54d1543e23e5	169	void pppInitStruct()
nixnax	142:54d1543e23e5	170	{
nixnax	223:917b554cb8a5	171	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	172	ppp.online=0;
nixnax	142:54d1543e23e5	173	ppp.rx.tail=0;
nixnax	142:54d1543e23e5	174	ppp.rx.rtail=0;
nixnax	142:54d1543e23e5	175	ppp.rx.head=0;
nixnax	142:54d1543e23e5	176	ppp.rx.buflevel=0;
nixnax	209:aa514cd631ee	177	ppp.rx.maxbuflevel=0;
nixnax	221:1d7c32d8256b	178	ppp.rx.bufferfull=0;
nixnax	142:54d1543e23e5	179	ppp.pkt.len=0;
nixnax	154:18b2bd92f557	180	ppp.ipData.ident=10000; // easy to recognize in ip packet dumps
nixnax	142:54d1543e23e5	181	ppp.ledState=0;
nixnax	142:54d1543e23e5	182	ppp.hdlc.frameStartIndex=0;
nixnax	146:a45f49a2b29c	183	ppp.responseCounter=0;
nixnax	239:426e50519204	184	ppp.pingCount=0; // number of ICMP pings we have received
nixnax	142:54d1543e23e5	185	ppp.firstFrame=1;
nixnax	175:b4e6f8a6fe00	186	ppp.ppp = (pppHeaderType *)ppp.pkt.buf; // pointer to ppp header
nixnax	175:b4e6f8a6fe00	187	ppp.ip = (ipHeaderType *)(ppp.pkt.buf+4); // pointer to IP header
nixnax	142:54d1543e23e5	188	}
nixnax	142:54d1543e23e5	189
nixnax	142:54d1543e23e5	190	/// Toggle the LED on every second PPP packet received
nixnax	142:54d1543e23e5	191	void led1Toggle()
nixnax	142:54d1543e23e5	192	{
nixnax	142:54d1543e23e5	193	led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax	143:c5019f856a56	194	ppp.ledState++;
nixnax	142:54d1543e23e5	195	}
nixnax	142:54d1543e23e5	196
nixnax	179:ba2b2ddd0da5	197	/// Returns 1 after a connect message, 0 at startup or after a disconnect message
nixnax	150:3366bf3d294e	198	int connectedPpp()
nixnax	142:54d1543e23e5	199	{
nixnax	142:54d1543e23e5	200	return ppp.online;
nixnax	143:c5019f856a56	201	}
nixnax	142:54d1543e23e5	202
nixnax	179:ba2b2ddd0da5	203	/// PPP serial port receive interrupt handler.
nixnax	143:c5019f856a56	204	/// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax	143:c5019f856a56	205	/// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax	179:ba2b2ddd0da5	206	void pppReceiveHandler()
nixnax	142:54d1543e23e5	207	{
nixnax	142:54d1543e23e5	208	char ch;
nixnax	179:ba2b2ddd0da5	209	while ( pc.readable() ) {
nixnax	223:917b554cb8a5	210	int localHead = (ppp.rx.head+1); // local head index
nixnax	223:917b554cb8a5	211	if (localHead > RXBUFLEN) localHead=0; // increment and wrap head index
nixnax	223:917b554cb8a5	212	if ( localHead == ppp.rx.rtail ) {
nixnax	221:1d7c32d8256b	213	ppp.rx.bufferfull = 1; // set flag if rx buffer is full
nixnax	221:1d7c32d8256b	214	return; // don't read if rx buffer is full
nixnax	142:54d1543e23e5	215	}
nixnax	142:54d1543e23e5	216	ch = pc.getc(); // read new character
nixnax	142:54d1543e23e5	217	ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax	209:aa514cd631ee	218	if (ch == 0x7E) { // check for ppp frame start character
nixnax	209:aa514cd631ee	219	if ( ppp.online == 0 ) { // check if we are offline
nixnax	209:aa514cd631ee	220	ppp.online = 1; // if we see a frame start character we immediately change status to online
nixnax	142:54d1543e23e5	221	}
nixnax	142:54d1543e23e5	222	}
nixnax	223:917b554cb8a5	223	ppp.rx.head = localHead; // update real head pointer
nixnax	221:1d7c32d8256b	224	ppp.rx.buflevel++; // update buffer level counter
nixnax	209:aa514cd631ee	225	if ( ppp.rx.buflevel > ppp.rx.maxbuflevel ) {
nixnax	221:1d7c32d8256b	226	ppp.rx.maxbuflevel = ppp.rx.buflevel; // remember the maximum usage of rx buffer
nixnax	209:aa514cd631ee	227	}
nixnax	142:54d1543e23e5	228	}
nixnax	142:54d1543e23e5	229	}
nixnax	142:54d1543e23e5	230
nixnax	145:098b6ed2f7f2	231	/// update the cumulative PPP FCS (frame check sequence)
nixnax	226:4898247048c7	232	void fcsDo(register int x)
nixnax	142:54d1543e23e5	233	{
nixnax	230:ee097c486e45	234	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	235	x>>=1;
nixnax	230:ee097c486e45	236	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	237	x>>=1;
nixnax	230:ee097c486e45	238	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	239	x>>=1;
nixnax	230:ee097c486e45	240	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	241	x>>=1;
nixnax	230:ee097c486e45	242	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	243	x>>=1;
nixnax	230:ee097c486e45	244	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	245	x>>=1;
nixnax	230:ee097c486e45	246	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	247	x>>=1;
nixnax	230:ee097c486e45	248	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	142:54d1543e23e5	249	}
nixnax	142:54d1543e23e5	250
nixnax	145:098b6ed2f7f2	251	/// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax	145:098b6ed2f7f2	252	int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax	142:54d1543e23e5	253	{
nixnax	226:4898247048c7	254	ppp.fcs=0xffff; // fcs initial value
nixnax	145:098b6ed2f7f2	255	for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax	145:098b6ed2f7f2	256	return ppp.fcs;
nixnax	142:54d1543e23e5	257	}
nixnax	142:54d1543e23e5	258
nixnax	142:54d1543e23e5	259	/// Get one character from our received PPP buffer
nixnax	142:54d1543e23e5	260	int pc_getBuf()
nixnax	142:54d1543e23e5	261	{
nixnax	142:54d1543e23e5	262	int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax	230:ee097c486e45	263	int temptail = ppp.rx.tail+1;
nixnax	230:ee097c486e45	264	if (temptail > RXBUFLEN) temptail=0;
nixnax	142:54d1543e23e5	265	ppp.rx.buflevel--;
nixnax	230:ee097c486e45	266	ppp.rx.tail = temptail;
nixnax	142:54d1543e23e5	267	return x;
nixnax	142:54d1543e23e5	268	}
nixnax	142:54d1543e23e5	269
nixnax	142:54d1543e23e5	270	/// Dump a PPP frame to the debug serial port
nixnax	142:54d1543e23e5	271	/// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax	142:54d1543e23e5	272	/// Capture the frame's hex output in your terminal program and save as a text file
nixnax	164:c3de3d212c4b	273	/// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax	142:54d1543e23e5	274	void dumpPPPFrame()
nixnax	142:54d1543e23e5	275	{
nixnax	230:ee097c486e45	276	char pbuf[100];
nixnax	142:54d1543e23e5	277	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	210:a2a651249a9a	278
nixnax	142:54d1543e23e5	279	sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax	210:a2a651249a9a	280
nixnax	221:1d7c32d8256b	281	debugPuts(pbuf);
nixnax	142:54d1543e23e5	282	}
nixnax	210:a2a651249a9a	283
nixnax	142:54d1543e23e5	284	sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax	210:a2a651249a9a	285
nixnax	221:1d7c32d8256b	286	debugPuts(pbuf);
nixnax	142:54d1543e23e5	287	}
nixnax	142:54d1543e23e5	288
nixnax	142:54d1543e23e5	289	/// Process a received PPP frame
nixnax	142:54d1543e23e5	290	void processPPPFrame(int start, int end)
nixnax	142:54d1543e23e5	291	{
nixnax	226:4898247048c7	292	led1Toggle(); // change led1 state on received frames
nixnax	142:54d1543e23e5	293	if(start==end) {
nixnax	142:54d1543e23e5	294	return; // empty frame
nixnax	142:54d1543e23e5	295	}
nixnax	226:4898247048c7	296	ppp.fcs=0xffff; // fcs initial value
nixnax	142:54d1543e23e5	297	char * dest = ppp.pkt.buf;
nixnax	142:54d1543e23e5	298	ppp.pkt.len=0;
nixnax	142:54d1543e23e5	299	int unstuff=0;
nixnax	142:54d1543e23e5	300	int idx = start;
nixnax	142:54d1543e23e5	301	while(1) {
nixnax	142:54d1543e23e5	302	if (unstuff==0) {
nixnax	142:54d1543e23e5	303	if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax	142:54d1543e23e5	304	else {
nixnax	142:54d1543e23e5	305	*dest = ppp.rx.buf[idx];
nixnax	142:54d1543e23e5	306	ppp.pkt.len++;
nixnax	142:54d1543e23e5	307	dest++;
nixnax	145:098b6ed2f7f2	308	fcsDo(ppp.rx.buf[idx]);
nixnax	142:54d1543e23e5	309	}
nixnax	142:54d1543e23e5	310	} else { // unstuff characters prefixed with 0x7d
nixnax	142:54d1543e23e5	311	*dest = ppp.rx.buf[idx]^0x20;
nixnax	142:54d1543e23e5	312	ppp.pkt.len++;
nixnax	142:54d1543e23e5	313	dest++;
nixnax	145:098b6ed2f7f2	314	fcsDo(ppp.rx.buf[idx]^0x20);
nixnax	142:54d1543e23e5	315	unstuff=0;
nixnax	142:54d1543e23e5	316	}
nixnax	216:e3c5a5b47295	317	idx = idx+1;
nixnax	216:e3c5a5b47295	318	if (idx > RXBUFLEN) idx=0;
nixnax	142:54d1543e23e5	319	if (idx == end) break;
nixnax	142:54d1543e23e5	320	}
nixnax	145:098b6ed2f7f2	321	ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax	226:4898247048c7	322	#ifdef DUMP_RECEIVED_PPP_FRAMES_YES
nixnax	226:4898247048c7	323	dumpPPPFrame(); // hex dump ALL ppp frames to the debug port
nixnax	226:4898247048c7	324	#endif
nixnax	142:54d1543e23e5	325	if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax	142:54d1543e23e5	326	determinePacketType();
nixnax	142:54d1543e23e5	327	} else {
nixnax	142:54d1543e23e5	328	#define REPORT_FCS_ERROR_YES
nixnax	142:54d1543e23e5	329	#ifdef REPORT_FCS_ERROR_YES
nixnax	230:ee097c486e45	330	char pbuf[100]; // local print buffer
nixnax	142:54d1543e23e5	331	sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax	221:1d7c32d8256b	332	debugPuts( pbuf );
nixnax	226:4898247048c7	333	#define DUMP_PPP_FRAME_ON_ERROR_NO
nixnax	226:4898247048c7	334	#ifdef DUMP_PPP_FRAME_ON_ERROR_YES
nixnax	226:4898247048c7	335	dumpPPPFrame(); // dump frames with errors in them
nixnax	226:4898247048c7	336	#endif
nixnax	142:54d1543e23e5	337	#endif
nixnax	142:54d1543e23e5	338	}
nixnax	142:54d1543e23e5	339	}
nixnax	142:54d1543e23e5	340
nixnax	142:54d1543e23e5	341	/// do PPP HDLC-like handling of special (flag) characters
nixnax	143:c5019f856a56	342	void hdlcPut(int ch)
nixnax	142:54d1543e23e5	343	{
nixnax	142:54d1543e23e5	344	if ( (ch<0x20) \|\| (ch==0x7d) \|\| (ch==0x7e) ) {
nixnax	226:4898247048c7	345	pc.putc(0x7d);
nixnax	226:4898247048c7	346	pc.putc(ch^0x20); // these characters need special handling
nixnax	142:54d1543e23e5	347	} else {
nixnax	226:4898247048c7	348	pc.putc(ch);
nixnax	142:54d1543e23e5	349	}
nixnax	142:54d1543e23e5	350	}
nixnax	142:54d1543e23e5	351
nixnax	142:54d1543e23e5	352	/// send a PPP frame in HDLC format
nixnax	144:01d98cf7738e	353	void sendPppFrame()
nixnax	143:c5019f856a56	354	{
nixnax	172:449dd7a28955	355	ppp.responseCounter++; // count the number of ppp frames we send
nixnax	145:098b6ed2f7f2	356	int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax	142:54d1543e23e5	357	ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax	142:54d1543e23e5	358	ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax	226:4898247048c7	359	pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax	142:54d1543e23e5	360	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	226:4898247048c7	361	// wait_us(86); // wait one character time
nixnax	210:a2a651249a9a	362
nixnax	142:54d1543e23e5	363	hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax	142:54d1543e23e5	364	}
nixnax	226:4898247048c7	365	pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax	142:54d1543e23e5	366	}
nixnax	142:54d1543e23e5	367
nixnax	143:c5019f856a56	368	/// 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	369	int bufferToIP(char * buffer)
nixnax	143:c5019f856a56	370	{
nixnax	143:c5019f856a56	371	int result=0;
nixnax	143:c5019f856a56	372	for(int i=0; i<4; i++) result = (result<<8)\|(*buffer++ & 0xff);
nixnax	143:c5019f856a56	373	return result;
nixnax	143:c5019f856a56	374	}
nixnax	143:c5019f856a56	375
nixnax	177:dab9e685af53	376	/// convert 4-byte ip address to 32-bit
nixnax	228:7fb878500862	377	unsigned int integersToIp( int a, int b, int c, int d)
nixnax	179:ba2b2ddd0da5	378	{
nixnax	177:dab9e685af53	379	return a<<24 \| b<<16 \| c<<8 \| d;
nixnax	177:dab9e685af53	380	}
nixnax	177:dab9e685af53	381
nixnax	142:54d1543e23e5	382	/// handle IPCP configuration requests
nixnax	142:54d1543e23e5	383	void ipcpConfigRequestHandler()
nixnax	142:54d1543e23e5	384	{
nixnax	230:ee097c486e45	385	debugPuts("Their IPCP Config Req, Our Ack\n");
nixnax	173:6774a0c851c4	386	if(ppp.ipcp->request[0]==3) {
nixnax	143:c5019f856a56	387	ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax	173:6774a0c851c4	388	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	389	}
nixnax	143:c5019f856a56	390
nixnax	167:ff8a2d8beeb1	391	ppp.ipcp->code=2; // change code to ack
nixnax	144:01d98cf7738e	392	sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax	142:54d1543e23e5	393
nixnax	230:ee097c486e45	394	debugPuts("Our IPCP Ask (no options)\n");
nixnax	167:ff8a2d8beeb1	395	ppp.ipcp->code=1; // change code to request
nixnax	167:ff8a2d8beeb1	396	ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax	167:ff8a2d8beeb1	397	ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax	144:01d98cf7738e	398	sendPppFrame(); // send our request
nixnax	142:54d1543e23e5	399	}
nixnax	142:54d1543e23e5	400
nixnax	142:54d1543e23e5	401	/// handle IPCP acknowledge (do nothing)
nixnax	142:54d1543e23e5	402	void ipcpAckHandler()
nixnax	142:54d1543e23e5	403	{
nixnax	230:ee097c486e45	404	debugPuts("Their IPCP Grant\n");
nixnax	142:54d1543e23e5	405	}
nixnax	142:54d1543e23e5	406
nixnax	143:c5019f856a56	407	/// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax	143:c5019f856a56	408	/// 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	409	void ipcpNackHandler()
nixnax	142:54d1543e23e5	410	{
nixnax	230:ee097c486e45	411	debugPuts("Their IPCP Nack\n");
nixnax	173:6774a0c851c4	412	if (ppp.ipcp->request[0]==3) { // check if the NACK contains an IP address parameter
nixnax	167:ff8a2d8beeb1	413	ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax	144:01d98cf7738e	414	sendPppFrame(); // let's request this IP address as ours
nixnax	230:ee097c486e45	415	debugPuts("Our IPCP ACK (received an IP)\n");
nixnax	146:a45f49a2b29c	416	} else { // if it's not an IP nack we ignore it
nixnax	230:ee097c486e45	417	debugPuts("IPCP Nack Ignored\n");
nixnax	146:a45f49a2b29c	418	}
nixnax	142:54d1543e23e5	419	}
nixnax	142:54d1543e23e5	420
nixnax	142:54d1543e23e5	421	/// handle all other IPCP requests (by ignoring them)
nixnax	142:54d1543e23e5	422	void ipcpDefaultHandler()
nixnax	142:54d1543e23e5	423	{
nixnax	230:ee097c486e45	424	debugPuts("Their IPCP Other\n");
nixnax	142:54d1543e23e5	425	}
nixnax	142:54d1543e23e5	426
nixnax	142:54d1543e23e5	427	/// process an incoming IPCP packet
nixnax	142:54d1543e23e5	428	void IPCPframe()
nixnax	142:54d1543e23e5	429	{
nixnax	167:ff8a2d8beeb1	430	int action = ppp.ipcp->code; // packet type is here
nixnax	167:ff8a2d8beeb1	431	switch (action) {
nixnax	142:54d1543e23e5	432	case 1:
nixnax	142:54d1543e23e5	433	ipcpConfigRequestHandler();
nixnax	142:54d1543e23e5	434	break;
nixnax	142:54d1543e23e5	435	case 2:
nixnax	142:54d1543e23e5	436	ipcpAckHandler();
nixnax	142:54d1543e23e5	437	break;
nixnax	142:54d1543e23e5	438	case 3:
nixnax	142:54d1543e23e5	439	ipcpNackHandler();
nixnax	142:54d1543e23e5	440	break;
nixnax	142:54d1543e23e5	441	default:
nixnax	142:54d1543e23e5	442	ipcpDefaultHandler();
nixnax	142:54d1543e23e5	443	}
nixnax	142:54d1543e23e5	444	}
nixnax	142:54d1543e23e5	445
nixnax	142:54d1543e23e5	446	/// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax	161:d59f778bc8ab	447	unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax	142:54d1543e23e5	448	{
nixnax	159:4d1bf96a59cd	449	unsigned int i,hi,lo;
nixnax	142:54d1543e23e5	450	unsigned char placeHolder;
nixnax	161:d59f778bc8ab	451	if (restart) ppp.sum=0;
nixnax	142:54d1543e23e5	452	if (len&1) {
nixnax	142:54d1543e23e5	453	placeHolder = ptr[len];
nixnax	142:54d1543e23e5	454	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	455	}
nixnax	142:54d1543e23e5	456	i=0;
nixnax	142:54d1543e23e5	457	while ( i<len ) {
nixnax	210:a2a651249a9a	458
nixnax	142:54d1543e23e5	459	hi = ptr[i++];
nixnax	142:54d1543e23e5	460	lo = ptr[i++];
nixnax	159:4d1bf96a59cd	461	ppp.sum = ppp.sum + ((hi<<8)\|lo);
nixnax	142:54d1543e23e5	462	}
nixnax	142:54d1543e23e5	463	if (len&1) {
nixnax	142:54d1543e23e5	464	ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax	142:54d1543e23e5	465	}
nixnax	159:4d1bf96a59cd	466	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax	159:4d1bf96a59cd	467	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax	159:4d1bf96a59cd	468	return ~ppp.sum;
nixnax	142:54d1543e23e5	469	}
nixnax	142:54d1543e23e5	470
nixnax	142:54d1543e23e5	471	/// perform the checksum on an IP header
nixnax	146:a45f49a2b29c	472	void IpHeaderCheckSum()
nixnax	142:54d1543e23e5	473	{
nixnax	161:d59f778bc8ab	474	ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax	161:d59f778bc8ab	475	int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax	161:d59f778bc8ab	476	unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax	161:d59f778bc8ab	477	ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax	146:a45f49a2b29c	478	}
nixnax	146:a45f49a2b29c	479
nixnax	147:0f40005cbc5f	480	/// swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	481	void swapIpAddresses()
nixnax	147:0f40005cbc5f	482	{
nixnax	162:594729c0e5c1	483	unsigned int tempHold;
nixnax	162:594729c0e5c1	484	tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax	162:594729c0e5c1	485	ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax	162:594729c0e5c1	486	ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax	147:0f40005cbc5f	487	}
nixnax	147:0f40005cbc5f	488
nixnax	149:969d98f6fb88	489	/// swap the IP source and destination ports
nixnax	149:969d98f6fb88	490	void swapIpPorts()
nixnax	149:969d98f6fb88	491	{
nixnax	173:6774a0c851c4	492	int headerSizeIP = 4 * (ppp.ip->headerLength); // calculate size of IP header
nixnax	173:6774a0c851c4	493	char * ipSrcPort = ppp.ipStart + headerSizeIP + 0; // ip source port location
nixnax	173:6774a0c851c4	494	char * ipDstPort = ppp.ipStart + headerSizeIP + 2; // ip destin port location
nixnax	149:969d98f6fb88	495	char tempHold[2];
nixnax	149:969d98f6fb88	496	memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax	149:969d98f6fb88	497	memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax	149:969d98f6fb88	498	memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax	149:969d98f6fb88	499	}
nixnax	149:969d98f6fb88	500
nixnax	170:3d3b2126181c	501	/// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax	170:3d3b2126181c	502	void checkSumPseudoHeader( unsigned int packetLength )
nixnax	170:3d3b2126181c	503	{
nixnax	170:3d3b2126181c	504	// 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	505	pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax	170:3d3b2126181c	506	pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax	170:3d3b2126181c	507	pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax	170:3d3b2126181c	508	pseudoHeader.zero = 0; // zero byte
nixnax	170:3d3b2126181c	509	pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax	170:3d3b2126181c	510	pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax	170:3d3b2126181c	511	dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax	170:3d3b2126181c	512	}
nixnax	170:3d3b2126181c	513
nixnax	171:46b36d4edd1d	514	/// initialize an IP packet to send
nixnax	171:46b36d4edd1d	515	void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax	171:46b36d4edd1d	516	{
nixnax	171:46b36d4edd1d	517	ppp.ppp->address = 0xff;
nixnax	171:46b36d4edd1d	518	ppp.ppp->control = 3;
nixnax	171:46b36d4edd1d	519	ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax	171:46b36d4edd1d	520	ppp.ip->version = 4;
nixnax	171:46b36d4edd1d	521	ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax	171:46b36d4edd1d	522	ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax	171:46b36d4edd1d	523	ppp.ip->dontFragment=1;
nixnax	171:46b36d4edd1d	524	ppp.ip->ttl=128;
nixnax	171:46b36d4edd1d	525	ppp.ip->protocol = protocol; // udp
nixnax	171:46b36d4edd1d	526	ppp.ip->srcAdrR = __REV(srcIp);
nixnax	171:46b36d4edd1d	527	ppp.ip->dstAdrR = __REV(dstIp);
nixnax	171:46b36d4edd1d	528	ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax	171:46b36d4edd1d	529	ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax	171:46b36d4edd1d	530	ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax	171:46b36d4edd1d	531	}
nixnax	171:46b36d4edd1d	532
nixnax	171:46b36d4edd1d	533
nixnax	171:46b36d4edd1d	534	/// Build a UDP packet from scratch
nixnax	171:46b36d4edd1d	535	void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax	171:46b36d4edd1d	536	{
nixnax	171:46b36d4edd1d	537	struct {
nixnax	171:46b36d4edd1d	538	unsigned int ipAll; // length of entire ip packet
nixnax	171:46b36d4edd1d	539	unsigned int ipHeader; // length of ip header
nixnax	171:46b36d4edd1d	540	unsigned int udpAll; // length of entire udp packet
nixnax	171:46b36d4edd1d	541	unsigned int udpData; // length of udp data segment
nixnax	171:46b36d4edd1d	542	} len;
nixnax	171:46b36d4edd1d	543	len.ipHeader = 20; // ip header length
nixnax	171:46b36d4edd1d	544	len.udpData = msgLen; // udp data size
nixnax	171:46b36d4edd1d	545	len.udpAll = len.udpData+8; // update local udp packet length
nixnax	171:46b36d4edd1d	546	len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax	171:46b36d4edd1d	547	initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax	171:46b36d4edd1d	548	ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax	171:46b36d4edd1d	549	ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax	171:46b36d4edd1d	550	memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax	171:46b36d4edd1d	551	ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax	171:46b36d4edd1d	552	ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	553	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	554	checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	555	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	556	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	557	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	558	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	559	}
nixnax	171:46b36d4edd1d	560
nixnax	146:a45f49a2b29c	561	/// Process an incoming UDP packet.
nixnax	146:a45f49a2b29c	562	/// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax	146:a45f49a2b29c	563	void UDPpacket()
nixnax	146:a45f49a2b29c	564	{
nixnax	163:d1b4328e9f08	565	struct {
nixnax	163:d1b4328e9f08	566	unsigned int all; // length of entire ip packet
nixnax	163:d1b4328e9f08	567	unsigned int header; // length of ip header
nixnax	163:d1b4328e9f08	568	} ipLength;
nixnax	163:d1b4328e9f08	569
nixnax	163:d1b4328e9f08	570	struct {
nixnax	165:c47826d07e0d	571	unsigned int all; // length of entire udp packet
nixnax	163:d1b4328e9f08	572	unsigned int data; // length of udp data segment
nixnax	163:d1b4328e9f08	573	} udpLength;
nixnax	163:d1b4328e9f08	574
nixnax	163:d1b4328e9f08	575	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	163:d1b4328e9f08	576	ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	171:46b36d4edd1d	577	udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax	163:d1b4328e9f08	578	udpLength.data = udpLength.all - 8; // size of udp data
nixnax	147:0f40005cbc5f	579
nixnax	146:a45f49a2b29c	580	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	171:46b36d4edd1d	581	char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax	171:46b36d4edd1d	582	char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax	163:d1b4328e9f08	583
nixnax	171:46b36d4edd1d	584	unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax	171:46b36d4edd1d	585	unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax	163:d1b4328e9f08	586
nixnax	163:d1b4328e9f08	587	if(v0) {
nixnax	163:d1b4328e9f08	588	debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax	163:d1b4328e9f08	589	debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax	163:d1b4328e9f08	590	debugPrintf("Len %03d", udpLength);
nixnax	163:d1b4328e9f08	591	}
nixnax	146:a45f49a2b29c	592	if (v1) {
nixnax	163:d1b4328e9f08	593	int printSize = udpLength.data;
nixnax	146:a45f49a2b29c	594	if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax	146:a45f49a2b29c	595	for (int i=0; i<printSize; i++) {
nixnax	163:d1b4328e9f08	596	char ch = ppp.udp->data[i];
nixnax	146:a45f49a2b29c	597	if (ch>31 && ch<127) {
nixnax	146:a45f49a2b29c	598	debugPrintf("%c", ch);
nixnax	146:a45f49a2b29c	599	} else {
nixnax	230:ee097c486e45	600	debugPuts("_");
nixnax	146:a45f49a2b29c	601	}
nixnax	146:a45f49a2b29c	602	}
nixnax	146:a45f49a2b29c	603	}
nixnax	230:ee097c486e45	604	if (v0) debugPuts("\n");
nixnax	146:a45f49a2b29c	605	#endif
nixnax	163:d1b4328e9f08	606	int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax	163:d1b4328e9f08	607	int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax	146:a45f49a2b29c	608	if ( (echoFound) \|\| (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax	146:a45f49a2b29c	609	if (echoFound) {
nixnax	171:46b36d4edd1d	610	swapIpAddresses(); // swap IP source and destination
nixnax	171:46b36d4edd1d	611	swapIpPorts(); // swap IP source and destination ports
nixnax	163:d1b4328e9f08	612	memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax	170:3d3b2126181c	613	int n=0;
nixnax	230:ee097c486e45	614	#define IDENTIFY_UDP_SERVER_NO
nixnax	230:ee097c486e45	615	#ifdef IDENTIFY_UDP_SERVER_YES
nixnax	170:3d3b2126181c	616	n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax	230:ee097c486e45	617	#endif
nixnax	168:c77eb908042a	618	udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax	171:46b36d4edd1d	619	// we may have changed data length, update all the lengths
nixnax	171:46b36d4edd1d	620	udpLength.all = udpLength.data+8; // update local udp packet length
nixnax	171:46b36d4edd1d	621	ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax	171:46b36d4edd1d	622	ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax	171:46b36d4edd1d	623	ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax	171:46b36d4edd1d	624	ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	625	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	626	checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	627	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	628	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	629	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	630	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	631	} else if ( testFound ) {
nixnax	171:46b36d4edd1d	632	unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax	171:46b36d4edd1d	633	unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax	171:46b36d4edd1d	634	unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax	171:46b36d4edd1d	635	unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax	172:449dd7a28955	636	int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter);
nixnax	171:46b36d4edd1d	637	sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax	146:a45f49a2b29c	638	}
nixnax	146:a45f49a2b29c	639	}
nixnax	142:54d1543e23e5	640	}
nixnax	142:54d1543e23e5	641
nixnax	174:e5a3f16421a5	642	/// UDP demo that sends a udp packet containing a character received from the second debug serial port.
nixnax	174:e5a3f16421a5	643	/// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
nixnax	178:3f17aa0ce5ce	644	/// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
nixnax	178:3f17aa0ce5ce	645	/// See http://www.wikihow.com/Enable-IP-Routing.
nixnax	179:ba2b2ddd0da5	646	/// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
nixnax	179:ba2b2ddd0da5	647	/// The netcat UDP receive command on the remote host would be: nc -ul 12345
nixnax	174:e5a3f16421a5	648	void sendUdpData()
nixnax	174:e5a3f16421a5	649	{
nixnax	174:e5a3f16421a5	650	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	179:ba2b2ddd0da5	651	if (ppp.online) {
nixnax	179:ba2b2ddd0da5	652	if (xx.readable()) {
nixnax	179:ba2b2ddd0da5	653	char inchar = xx.getc();
nixnax	179:ba2b2ddd0da5	654	xx.putc( inchar ); // echo the received character on the debug serial port
nixnax	228:7fb878500862	655	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	656	}
nixnax	174:e5a3f16421a5	657	}
nixnax	174:e5a3f16421a5	658	#endif
nixnax	174:e5a3f16421a5	659	}
nixnax	174:e5a3f16421a5	660
nixnax	142:54d1543e23e5	661	/// handle a PING ICMP (internet control message protocol) packet
nixnax	142:54d1543e23e5	662	void ICMPpacket() // internet control message protocol
nixnax	142:54d1543e23e5	663	{
nixnax	165:c47826d07e0d	664	struct {
nixnax	165:c47826d07e0d	665	unsigned int all; // length of entire ip packet
nixnax	165:c47826d07e0d	666	unsigned int header; // length of ip header
nixnax	165:c47826d07e0d	667	} ipLength;
nixnax	165:c47826d07e0d	668	struct {
nixnax	165:c47826d07e0d	669	unsigned int all; // length of entire udp packet
nixnax	165:c47826d07e0d	670	unsigned int data; // length of udp data segment
nixnax	165:c47826d07e0d	671	} icmpLength;
nixnax	165:c47826d07e0d	672	ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax	165:c47826d07e0d	673	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	165:c47826d07e0d	674	ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	165:c47826d07e0d	675	icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax	165:c47826d07e0d	676	icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax	142:54d1543e23e5	677	#define ICMP_TYPE_PING_REQUEST 8
nixnax	165:c47826d07e0d	678	if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax	165:c47826d07e0d	679	ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax	239:426e50519204	680	ppp.pingCount++; // count how many times we get pinged
nixnax	147:0f40005cbc5f	681	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	167:ff8a2d8beeb1	682	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	683	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	165:c47826d07e0d	684	int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax	165:c47826d07e0d	685	int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax	142:54d1543e23e5	686	if(1) {
nixnax	230:ee097c486e45	687	char pbuf[100];
nixnax	210:a2a651249a9a	688
nixnax	142:54d1543e23e5	689	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	690	debugPuts( pbuf );
nixnax	210:a2a651249a9a	691
nixnax	142:54d1543e23e5	692	sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax	210:a2a651249a9a	693
nixnax	221:1d7c32d8256b	694	debugPuts( pbuf );
nixnax	142:54d1543e23e5	695	}
nixnax	142:54d1543e23e5	696	#endif
nixnax	147:0f40005cbc5f	697	swapIpAddresses(); // swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	698	IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax	142:54d1543e23e5	699	#define ICMP_TYPE_ECHO_REPLY 0
nixnax	165:c47826d07e0d	700	ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax	165:c47826d07e0d	701	ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax	165:c47826d07e0d	702	unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax	165:c47826d07e0d	703	ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax	226:4898247048c7	704	#define DUMP_ICMP_PACKETS_NO
nixnax	226:4898247048c7	705	#ifdef DUMP_ICMP_PACKETS_YES
nixnax	165:c47826d07e0d	706	int printSize = icmpLength.data; // exclude size of icmp header
nixnax	142:54d1543e23e5	707	if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax	226:4898247048c7	708	for (int i=0; i<printSize; i++) {
nixnax	226:4898247048c7	709	char ch = ppp.icmp->data[i];
nixnax	226:4898247048c7	710	if (ch>31 && ch<127) {
nixnax	226:4898247048c7	711	debugPutc(ch);
nixnax	226:4898247048c7	712	} else {
nixnax	226:4898247048c7	713	debugPutc('_'); // for non-printable characters
nixnax	142:54d1543e23e5	714	}
nixnax	142:54d1543e23e5	715	}
nixnax	226:4898247048c7	716	debugPutc('\n');
nixnax	226:4898247048c7	717	#endif
nixnax	144:01d98cf7738e	718	sendPppFrame(); // reply to the ping
nixnax	142:54d1543e23e5	719	} else {
nixnax	142:54d1543e23e5	720	if (v0) {
nixnax	165:c47826d07e0d	721	debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax	142:54d1543e23e5	722	}
nixnax	142:54d1543e23e5	723	}
nixnax	142:54d1543e23e5	724	}
nixnax	142:54d1543e23e5	725
nixnax	142:54d1543e23e5	726	/// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax	142:54d1543e23e5	727	void IGMPpacket()
nixnax	142:54d1543e23e5	728	{
nixnax	142:54d1543e23e5	729	if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax	142:54d1543e23e5	730	}
nixnax	142:54d1543e23e5	731
nixnax	142:54d1543e23e5	732	/// dump the header of an IP pakcet on the (optional) debug serial port
nixnax	142:54d1543e23e5	733	void dumpHeaderIP (int outGoing)
nixnax	142:54d1543e23e5	734	{
nixnax	142:54d1543e23e5	735	#if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	210:a2a651249a9a	736
nixnax	155:9c6a1d249e26	737	int IPv4Id = __REV16(ppp.ip->identR);
nixnax	230:ee097c486e45	738	char pbuf[100]; // local print buffer
nixnax	142:54d1543e23e5	739	int n=0;
nixnax	142:54d1543e23e5	740	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	142:54d1543e23e5	741	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	742	#define DUMP_FULL_IP_ADDRESS_YES
nixnax	142:54d1543e23e5	743	#ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax	167:ff8a2d8beeb1	744	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	745	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	142:54d1543e23e5	746	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	747	#endif
nixnax	221:1d7c32d8256b	748	debugPuts( pbuf );
nixnax	142:54d1543e23e5	749	#ifndef TCP_HEADER_DUMP_YES
nixnax	221:1d7c32d8256b	750	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	751	#endif
nixnax	142:54d1543e23e5	752	#endif
nixnax	142:54d1543e23e5	753	}
nixnax	142:54d1543e23e5	754
nixnax	142:54d1543e23e5	755	/// dump a TCP header on the optional debug serial port
nixnax	142:54d1543e23e5	756	void dumpHeaderTCP(int outGoing)
nixnax	142:54d1543e23e5	757	{
nixnax	142:54d1543e23e5	758	#if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	155:9c6a1d249e26	759	char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax	142:54d1543e23e5	760	#define PRINT_ALL_TCP_FLAGS_YES
nixnax	142:54d1543e23e5	761	#ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax	155:9c6a1d249e26	762	memset(flagString,'.', 8); // fill string with "........"
nixnax	156:163c23249731	763	if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax	156:163c23249731	764	if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax	156:163c23249731	765	if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax	156:163c23249731	766	if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax	156:163c23249731	767	if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax	156:163c23249731	768	if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax	156:163c23249731	769	if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax	156:163c23249731	770	if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax	155:9c6a1d249e26	771	flagString[8]=0; // null terminate string
nixnax	142:54d1543e23e5	772	#else
nixnax	156:163c23249731	773	if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax	156:163c23249731	774	if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax	156:163c23249731	775	if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax	156:163c23249731	776	if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax	156:163c23249731	777	if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax	155:9c6a1d249e26	778	flagString[1]=0; // null terminate string
nixnax	142:54d1543e23e5	779	#endif
nixnax	221:1d7c32d8256b	780	debugPuts( flagString );
nixnax	142:54d1543e23e5	781	#define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	142:54d1543e23e5	782	#ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	221:1d7c32d8256b	783	debugPuts("\x1b[30m\n"); // write a black color and newline after every packet
nixnax	160:bd701ad564cb	784	#else
nixnax	221:1d7c32d8256b	785	debugPuts("\x1b[30m"); // write a black color after every packet
nixnax	142:54d1543e23e5	786	#endif
nixnax	156:163c23249731	787	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	788	debugPutc('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax	142:54d1543e23e5	789	}
nixnax	142:54d1543e23e5	790	#endif
nixnax	142:54d1543e23e5	791	}
nixnax	142:54d1543e23e5	792
nixnax	143:c5019f856a56	793	/// Encode a buffer in base-64
nixnax	184:4133f557d4d4	794	const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax	142:54d1543e23e5	795	void enc64(char * in, char * out, int len)
nixnax	142:54d1543e23e5	796	{
nixnax	142:54d1543e23e5	797	int i,j,a,b,c;
nixnax	142:54d1543e23e5	798	i=0;
nixnax	142:54d1543e23e5	799	j=0;
nixnax	142:54d1543e23e5	800	while(1) {
nixnax	142:54d1543e23e5	801	if (i<len) {
nixnax	142:54d1543e23e5	802	a = in[i++];
nixnax	142:54d1543e23e5	803	out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax	142:54d1543e23e5	804	} else break;
nixnax	142:54d1543e23e5	805	if (i<len) {
nixnax	142:54d1543e23e5	806	b = in[i++];
nixnax	142:54d1543e23e5	807	out[j++] = lut[ ( (a << 4) & 0x30) \| ( (b >> 4) & 0x0f) ];
nixnax	142:54d1543e23e5	808	out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax	142:54d1543e23e5	809	} else out[j++] = '=';
nixnax	142:54d1543e23e5	810	if (i<len) {
nixnax	142:54d1543e23e5	811	c = in[i++];
nixnax	142:54d1543e23e5	812	j--;
nixnax	142:54d1543e23e5	813	out[j++] = lut[ ( (b << 2) & 0x3c) \| ( (c >> 6) & 0x03) ];
nixnax	142:54d1543e23e5	814	out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax	142:54d1543e23e5	815	} else out[j++] = '=';
nixnax	142:54d1543e23e5	816	}
nixnax	142:54d1543e23e5	817	out[j]=0;
nixnax	142:54d1543e23e5	818	}
nixnax	142:54d1543e23e5	819
nixnax	160:bd701ad564cb	820	/// Handle a request for an http websocket.
nixnax	160:bd701ad564cb	821	/// 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	822	int webSocketHandler(char * dataStart)
nixnax	142:54d1543e23e5	823	{
nixnax	142:54d1543e23e5	824	int n=0; // byte counter
nixnax	184:4133f557d4d4	825	char * key = strstr(dataStart, "Sec-WebSocket-Key:"); // search for the key in the payload
nixnax	142:54d1543e23e5	826	if (key != NULL) {
nixnax	184:4133f557d4d4	827	key = key + 18; // skip over the key ident string "Sec-WebSocket-Key:"
nixnax	221:1d7c32d8256b	828	if (v0) debugPuts("WebSocket Request\n");
nixnax	184:4133f557d4d4	829	while ( strchr(lut, *key) == NULL) key++; // skip non-valid base-64 characters (whitespace)
nixnax	184:4133f557d4d4	830	char challenge [80];
nixnax	184:4133f557d4d4	831	int i=0;
nixnax	184:4133f557d4d4	832	char * copyTo = challenge;
nixnax	184:4133f557d4d4	833	while (strchr(lut, *key) != NULL) { // copy while we see valid base-64 characters
nixnax	184:4133f557d4d4	834	if (i++ >40) break; // prevent buffer overflow
nixnax	184:4133f557d4d4	835	copyTo++ = key++; // copy next valid base-64 character
nixnax	184:4133f557d4d4	836	}
nixnax	184:4133f557d4d4	837	strcpy(copyTo,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // append websocket gui code
nixnax	226:4898247048c7	838	#define DUMP_WEBSOCKET_CHALLENGE_NO
nixnax	226:4898247048c7	839	#ifdef DUMP_WEBSOCKET_CHALLENGE_YES
nixnax	226:4898247048c7	840	debugPrintf("Challenge is %s\n", challenge); // the string we hash for the challenge
nixnax	227:f87156f9ef11	841	#endif
nixnax	142:54d1543e23e5	842	char shaOutput [20]; // sha1 output
nixnax	184:4133f557d4d4	843	sha1( shaOutput, challenge, strlen(challenge)); // hash the challenge
nixnax	142:54d1543e23e5	844	char encOut[50];
nixnax	184:4133f557d4d4	845	enc64( shaOutput, encOut, 20); // base-64 encode
nixnax	142:54d1543e23e5	846	char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax	142:54d1543e23e5	847	char * version = challenge;
nixnax	184:4133f557d4d4	848	strncpy(version, versionstring,70); // copy their version string
nixnax	142:54d1543e23e5	849	*strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax	240:d7a01533397d	850	memset(dataStart,0,500); // blank out old data before sending the websocket response header
nixnax	142:54d1543e23e5	851	n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax	142:54d1543e23e5	852	n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax	142:54d1543e23e5	853	n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax	142:54d1543e23e5	854	n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax	142:54d1543e23e5	855	n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax	142:54d1543e23e5	856	n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax	142:54d1543e23e5	857	n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax	142:54d1543e23e5	858	}
nixnax	142:54d1543e23e5	859	return n; // this response should satisfy a web browser's websocket protocol request
nixnax	142:54d1543e23e5	860	}
nixnax	142:54d1543e23e5	861
nixnax	142:54d1543e23e5	862	#define TCP_FLAG_ACK (1<<4)
nixnax	142:54d1543e23e5	863	#define TCP_FLAG_SYN (1<<1)
nixnax	142:54d1543e23e5	864	#define TCP_FLAG_PSH (1<<3)
nixnax	142:54d1543e23e5	865	#define TCP_FLAG_RST (1<<2)
nixnax	142:54d1543e23e5	866	#define TCP_FLAG_FIN (1<<0)
nixnax	142:54d1543e23e5	867
nixnax	142:54d1543e23e5	868	/// respond to an HTTP request
nixnax	185:4cd8f91e9d49	869	int httpResponse(char * dataStart, int * flags)
nixnax	142:54d1543e23e5	870	{
nixnax	142:54d1543e23e5	871	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	872	n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax	160:bd701ad564cb	873	if (n>0) return n; // if n>0 we already have a response, so return
nixnax	142:54d1543e23e5	874
nixnax	142:54d1543e23e5	875	int nHeader; // byte size of HTTP header
nixnax	142:54d1543e23e5	876	int contentLengthStart; // index where HTML starts
nixnax	142:54d1543e23e5	877	int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax	185:4cd8f91e9d49	878	*flags = TCP_FLAG_ACK \| TCP_FLAG_FIN; // the default case is that we close the connection
nixnax	142:54d1543e23e5	879
nixnax	142:54d1543e23e5	880	httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax	142:54d1543e23e5	881	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	882	httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	883	httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	884	// for example, you could try this using netcat (nc): echo "GET /x" \| nc 172.10.10.2
nixnax	210:a2a651249a9a	885	if( (httpGetRoot==0) \|\| (httpGetx==0) \|\| (httpGet5 == 'w') ) {
nixnax	229:a81c37376187	886	n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed PPP-Blinky\r\n"); // 200 OK header
nixnax	142:54d1543e23e5	887	} else {
nixnax	229:a81c37376187	888	n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed PPP-Blinky\r\n"); // 404 header
nixnax	142:54d1543e23e5	889	}
nixnax	142:54d1543e23e5	890	n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax	142:54d1543e23e5	891	contentLengthStart = n; // remember where Content-Length is in buffer
nixnax	142:54d1543e23e5	892	n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax	142:54d1543e23e5	893	n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax	217:86498f9ab967	894	#define SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	895	#ifdef SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	896	// 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	897	n=n+sprintf(n+dataStart,"Maxbuflevel: %d\r\n", ppp.rx.maxbuflevel);
nixnax	210:a2a651249a9a	898	#endif
nixnax	241:dece92cb7296	899	#define SHOWPINGCOUNT_NO
nixnax	240:d7a01533397d	900	#ifdef SHOWPINGCOUNT_YES
nixnax	241:dece92cb7296	901	// 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	902	n=n+sprintf(n+dataStart,"PingCount: %d\r\n", ppp.pingCount);
nixnax	240:d7a01533397d	903	#endif
nixnax	142:54d1543e23e5	904	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	905	nHeader=n; // size of HTTP header
nixnax	210:a2a651249a9a	906
nixnax	142:54d1543e23e5	907	if( httpGetRoot == 0 ) {
nixnax	142:54d1543e23e5	908	// this is where we insert our web page into the buffer
nixnax	142:54d1543e23e5	909	memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax	142:54d1543e23e5	910	n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax	241:dece92cb7296	911	// naximum length of pingCount (maximum number of digits of an unsigned 32-bit int)
nixnax	241:dece92cb7296	912	#define PINGCOUNTMAXLEN (10)
nixnax	241:dece92cb7296	913	char pingCountString[PINGCOUNTMAXLEN+1]; // space for the ten digits and a string terminator 0
nixnax	241:dece92cb7296	914	snprintf(pingCountString,PINGCOUNTMAXLEN+1,"%*d",PINGCOUNTMAXLEN,ppp.pingCount); // print number of ICMP pings right justified in 10 spaces
nixnax	241:dece92cb7296	915	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	916	if ( pingCountStart != NULL )
nixnax	241:dece92cb7296	917	memcpy(pingCountStart, pingCountString, PINGCOUNTMAXLEN); // copy ping count over the ten zeros in the page
nixnax	210:a2a651249a9a	918	} else if ( httpGet5 == 'w' ) { // "w" is a special page for websocket demo
nixnax	142:54d1543e23e5	919	memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax	142:54d1543e23e5	920	n = n + sizeof(webSocketPage)-1; // one less than size
nixnax	185:4cd8f91e9d49	921	*flags = TCP_FLAG_ACK \| TCP_FLAG_PSH; // for a websocket page we do NOT close the connection
nixnax	142:54d1543e23e5	922	} else {
nixnax	142:54d1543e23e5	923	if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax	142:54d1543e23e5	924	#define W3C_COMPLIANT_RESPONSE_NO
nixnax	142:54d1543e23e5	925	// change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax	142:54d1543e23e5	926	#ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax	142:54d1543e23e5	927	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax	146:a45f49a2b29c	928	n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax	142:54d1543e23e5	929	#else
nixnax	142:54d1543e23e5	930	if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax	167:ff8a2d8beeb1	931	n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax	142:54d1543e23e5	932	}
nixnax	142:54d1543e23e5	933	// /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax	146:a45f49a2b29c	934	n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax	142:54d1543e23e5	935	#endif
nixnax	142:54d1543e23e5	936	} else {
nixnax	142:54d1543e23e5	937	// all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax	142:54d1543e23e5	938	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax	142:54d1543e23e5	939	n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax	142:54d1543e23e5	940	}
nixnax	142:54d1543e23e5	941	}
nixnax	142:54d1543e23e5	942	#define CONTENTLENGTHSIZE 5
nixnax	142:54d1543e23e5	943	char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax	142:54d1543e23e5	944	snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax	142:54d1543e23e5	945	memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax	142:54d1543e23e5	946	return n; // total byte size of our response
nixnax	142:54d1543e23e5	947	}
nixnax	142:54d1543e23e5	948
nixnax	160:bd701ad564cb	949	/// Handle TCP data that is not an HTTP GET.
nixnax	160:bd701ad564cb	950	/// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax	160:bd701ad564cb	951	/// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax	142:54d1543e23e5	952	int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax	142:54d1543e23e5	953	{
nixnax	142:54d1543e23e5	954	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	955	if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax	160:bd701ad564cb	956	char mask [4];
nixnax	160:bd701ad564cb	957	memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax	160:bd701ad564cb	958	int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax	160:bd701ad564cb	959	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	960	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	961	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	962	memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax	160:bd701ad564cb	963	n = len; // our response size remains exactly the same length as what we received
nixnax	142:54d1543e23e5	964	} else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax	142:54d1543e23e5	965	n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax	142:54d1543e23e5	966	dataStart[1]=0; // we don't have mask bytes on
nixnax	160:bd701ad564cb	967	} else {
nixnax	184:4133f557d4d4	968	if ( len > 1 ) { // we assume a length of 1 is a keep-alive or push packet
nixnax	221:1d7c32d8256b	969	if (v1) debugPuts("TCP data received\n"); // all other tcp push packets
nixnax	184:4133f557d4d4	970	}
nixnax	163:d1b4328e9f08	971	}
nixnax	142:54d1543e23e5	972	return n; // total byte size of our response
nixnax	142:54d1543e23e5	973	}
nixnax	142:54d1543e23e5	974
nixnax	173:6774a0c851c4	975	/// dump the TCP data to the debug serial port
nixnax	173:6774a0c851c4	976	void dumpDataTCP(int outGoing)
nixnax	173:6774a0c851c4	977	{
nixnax	173:6774a0c851c4	978	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	173:6774a0c851c4	979	if (v2) {
nixnax	173:6774a0c851c4	980	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	173:6774a0c851c4	981	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	982	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax	173:6774a0c851c4	983	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	173:6774a0c851c4	984	ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
nixnax	173:6774a0c851c4	985	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	173:6774a0c851c4	986	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	230:ee097c486e45	987	char pbuf[100]; // local print buffer
nixnax	173:6774a0c851c4	988	int n=0;
nixnax	210:a2a651249a9a	989
nixnax	173:6774a0c851c4	990	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	210:a2a651249a9a	991
nixnax	173:6774a0c851c4	992	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	993	if (n>95) debugPuts("n>pbuf overflow in dumpDataTCP()\n");
nixnax	210:a2a651249a9a	994
nixnax	221:1d7c32d8256b	995	debugPuts( pbuf );
nixnax	173:6774a0c851c4	996	if (tcpDataSize > 0) {
nixnax	173:6774a0c851c4	997	ppp.tcpData[tcpDataSize]=0; // insert a null after the data so debug printf stops printing after the data
nixnax	221:1d7c32d8256b	998	debugPuts( ppp.tcpData ); // print the tcp payload data
nixnax	221:1d7c32d8256b	999	debugPuts("\n");
nixnax	173:6774a0c851c4	1000	}
nixnax	221:1d7c32d8256b	1001	debugPuts( "\x1b[30m" ); // VT100 color code, print black
nixnax	173:6774a0c851c4	1002	}
nixnax	173:6774a0c851c4	1003	#endif
nixnax	173:6774a0c851c4	1004	}
nixnax	173:6774a0c851c4	1005
nixnax	142:54d1543e23e5	1006	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1007	/// 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	1008	void tcpHandler()
nixnax	142:54d1543e23e5	1009	{
nixnax	154:18b2bd92f557	1010	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	154:18b2bd92f557	1011	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	1012	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate TCP header start
nixnax	154:18b2bd92f557	1013	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	154:18b2bd92f557	1014	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	227:f87156f9ef11	1015	char * tcpDataIn = ppp.tcpStart + headerSizeTcp; // start of TCP data after TCP header
nixnax	154:18b2bd92f557	1016	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	154:18b2bd92f557	1017
nixnax	227:f87156f9ef11	1018	unsigned int seq_in = __REV(ppp.tcp->seqTcpR); // incoming sequence number
nixnax	227:f87156f9ef11	1019	unsigned int ack_in = __REV(ppp.tcp->ackTcpR); // incoming acknowledge number
nixnax	227:f87156f9ef11	1020	unsigned int ack_out = seq_in + tcpDataSize; // calculate the acknowledge based on size of received packet
nixnax	227:f87156f9ef11	1021	unsigned int seq_out = ack_in; // adopt their version of our sequence number as our sequence number
nixnax	142:54d1543e23e5	1022
nixnax	142:54d1543e23e5	1023	// first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax	173:6774a0c851c4	1024	headerSizeIp=20;
nixnax	173:6774a0c851c4	1025	ppp.ip->headerLength = headerSizeIp/4; // ip header is 20 bytes long
nixnax	173:6774a0c851c4	1026	ppp.ip->lengthR = __REV(40); // 20 ip header + 20 tcp header
nixnax	227:f87156f9ef11	1027	headerSizeTcp = 20; // shorten outgoing TCP header size to 20 bytes (no data)
nixnax	173:6774a0c851c4	1028	ppp.tcpStart = ppp.ipStart + headerSizeIp; // recalc TCP header start
nixnax	154:18b2bd92f557	1029	ppp.tcp->offset = (headerSizeTcp/4);
nixnax	173:6774a0c851c4	1030	char * tcpDataOut = ppp.tcpStart + headerSizeTcp; // start of outgoing data
nixnax	142:54d1543e23e5	1031
nixnax	142:54d1543e23e5	1032	int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax	142:54d1543e23e5	1033	int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax	160:bd701ad564cb	1034
nixnax	185:4cd8f91e9d49	1035	ppp.tcp->windowR = __REV16( 1200 ); // set tcp window size to 1200 bytes
nixnax	142:54d1543e23e5	1036
nixnax	142:54d1543e23e5	1037	// A sparse TCP flag interpreter that implements stateless TCP connections
nixnax	142:54d1543e23e5	1038
nixnax	156:163c23249731	1039	switch ( ppp.tcp->flag.All ) {
nixnax	142:54d1543e23e5	1040	case TCP_FLAG_SYN:
nixnax	142:54d1543e23e5	1041	flagsOut = TCP_FLAG_SYN \| TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax	142:54d1543e23e5	1042	seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax	142:54d1543e23e5	1043	ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1044	break;
nixnax	184:4133f557d4d4	1045	case TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1046	case TCP_FLAG_ACK \| TCP_FLAG_PSH:
nixnax	184:4133f557d4d4	1047	if ( (ppp.tcp->flag.All == TCP_FLAG_ACK) && (tcpDataSize == 0)) return; // handle zero-size ack messages by ignoring them
nixnax	142:54d1543e23e5	1048	if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax	237:796851817c26	1049	led1Toggle(); // toggle the LED one more time so we can visualize the HTTP GET
nixnax	179:ba2b2ddd0da5	1050	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // we have data, set the PSH flag
nixnax	185:4cd8f91e9d49	1051	dataLen = httpResponse(tcpDataOut, &flagsOut); // send an http response
nixnax	142:54d1543e23e5	1052	} else {
nixnax	158:841592aed956	1053	dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax	179:ba2b2ddd0da5	1054	if (dataLen > 0) flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // if we have any data set the PSH flag
nixnax	142:54d1543e23e5	1055	}
nixnax	142:54d1543e23e5	1056	break;
nixnax	142:54d1543e23e5	1057	case TCP_FLAG_FIN:
nixnax	142:54d1543e23e5	1058	case TCP_FLAG_FIN \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1059	case TCP_FLAG_FIN \| TCP_FLAG_PSH \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1060	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax	142:54d1543e23e5	1061	ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1062	break;
nixnax	142:54d1543e23e5	1063	default:
nixnax	179:ba2b2ddd0da5	1064	return; // ignore all other packets
nixnax	142:54d1543e23e5	1065	} // switch
nixnax	142:54d1543e23e5	1066
nixnax	142:54d1543e23e5	1067	// The TCP flag handling is now done
nixnax	142:54d1543e23e5	1068	// first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax	147:0f40005cbc5f	1069	swapIpAddresses(); // swap IP source and destination addresses
nixnax	149:969d98f6fb88	1070	swapIpPorts(); // swap IP source and destination ports
nixnax	142:54d1543e23e5	1071
nixnax	158:841592aed956	1072	ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	158:841592aed956	1073	ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	160:bd701ad564cb	1074
nixnax	156:163c23249731	1075	ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax	142:54d1543e23e5	1076
nixnax	159:4d1bf96a59cd	1077	// recalculate all the header sizes
nixnax	154:18b2bd92f557	1078	tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax	154:18b2bd92f557	1079	int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax	159:4d1bf96a59cd	1080	ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax	142:54d1543e23e5	1081	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	1082
nixnax	142:54d1543e23e5	1083	// the header is all set up, now do the IP and TCP checksums
nixnax	146:a45f49a2b29c	1084	IpHeaderCheckSum(); // calculate new IP header checksum
nixnax	170:3d3b2126181c	1085	checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax	159:4d1bf96a59cd	1086	ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	161:d59f778bc8ab	1087	unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax	159:4d1bf96a59cd	1088	ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	160:bd701ad564cb	1089
nixnax	170:3d3b2126181c	1090	dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax	170:3d3b2126181c	1091	dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax	173:6774a0c851c4	1092	dumpDataTCP(1); // dump outgoing TCP data before sending the frame
nixnax	226:4898247048c7	1093	#define WAIT_BEFORE_IP_SEND_NO
nixnax	226:4898247048c7	1094	#ifdef WAIT_BEFORE_IP_SEND_YES
nixnax	226:4898247048c7	1095	wait_ms(45); // 45 ms delay before sending frame
nixnax	226:4898247048c7	1096	#endif
nixnax	144:01d98cf7738e	1097	sendPppFrame(); // All preparation complete - send the TCP response
nixnax	226:4898247048c7	1098	#define DUMP_TRANSMITTED_PPP_NO
nixnax	226:4898247048c7	1099	#ifdef DUMP_TRANSMITTED_PPP_YES
nixnax	226:4898247048c7	1100	dumpPPPFrame(); // dump every transmitted ppp frame to debug port
nixnax	226:4898247048c7	1101	#endif
nixnax	142:54d1543e23e5	1102	memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax	142:54d1543e23e5	1103	}
nixnax	142:54d1543e23e5	1104
nixnax	142:54d1543e23e5	1105	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1106	void TCPpacket()
nixnax	142:54d1543e23e5	1107	{
nixnax	173:6774a0c851c4	1108	dumpHeaderIP(0); // dump incoming packet IP header
nixnax	173:6774a0c851c4	1109	dumpHeaderTCP(0); // dump incoming packet TCP header
nixnax	173:6774a0c851c4	1110	dumpDataTCP(0); // dump incoming packet data
nixnax	142:54d1543e23e5	1111	tcpHandler();
nixnax	142:54d1543e23e5	1112	}
nixnax	142:54d1543e23e5	1113
nixnax	142:54d1543e23e5	1114	/// handle the remaining IP protocols by ignoring them
nixnax	142:54d1543e23e5	1115	void otherProtocol()
nixnax	142:54d1543e23e5	1116	{
nixnax	230:ee097c486e45	1117	debugPuts("Other IP protocol");
nixnax	142:54d1543e23e5	1118	}
nixnax	142:54d1543e23e5	1119
nixnax	142:54d1543e23e5	1120	/// process an incoming IP packet
nixnax	142:54d1543e23e5	1121	void IPframe()
nixnax	142:54d1543e23e5	1122	{
nixnax	167:ff8a2d8beeb1	1123	int protocol = ppp.ip->protocol;
nixnax	142:54d1543e23e5	1124	switch (protocol) {
nixnax	142:54d1543e23e5	1125	case 1:
nixnax	142:54d1543e23e5	1126	ICMPpacket();
nixnax	142:54d1543e23e5	1127	break;
nixnax	142:54d1543e23e5	1128	case 2:
nixnax	142:54d1543e23e5	1129	IGMPpacket();
nixnax	142:54d1543e23e5	1130	break;
nixnax	142:54d1543e23e5	1131	case 17:
nixnax	142:54d1543e23e5	1132	UDPpacket();
nixnax	142:54d1543e23e5	1133	break;
nixnax	142:54d1543e23e5	1134	case 6:
nixnax	142:54d1543e23e5	1135	TCPpacket();
nixnax	142:54d1543e23e5	1136	break;
nixnax	142:54d1543e23e5	1137	default:
nixnax	142:54d1543e23e5	1138	otherProtocol();
nixnax	142:54d1543e23e5	1139	}
nixnax	142:54d1543e23e5	1140	}
nixnax	142:54d1543e23e5	1141
nixnax	227:f87156f9ef11	1142	/// process LCP packets
nixnax	142:54d1543e23e5	1143	void LCPframe()
nixnax	142:54d1543e23e5	1144	{
nixnax	175:b4e6f8a6fe00	1145	int code = ppp.lcp->code;
nixnax	142:54d1543e23e5	1146	switch (code) {
nixnax	227:f87156f9ef11	1147	case 1: // LCP configuration request
nixnax	231:6bd4523833a2	1148	debugPuts("LCP Config");
nixnax	227:f87156f9ef11	1149	if ( __REV16( ppp.lcp->lengthR ) == 4 ) {
nixnax	230:ee097c486e45	1150	debugPuts("LCP Ack\n");
nixnax	227:f87156f9ef11	1151	ppp.lcp->code=2; // acknowledge zero configuration request
nixnax	227:f87156f9ef11	1152	sendPppFrame();
nixnax	227:f87156f9ef11	1153	ppp.lcp->code=1; // request no options
nixnax	227:f87156f9ef11	1154	sendPppFrame();
nixnax	227:f87156f9ef11	1155	} else {
nixnax	230:ee097c486e45	1156	debugPuts("LCP request reject\n");
nixnax	227:f87156f9ef11	1157	ppp.lcp->code=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax	227:f87156f9ef11	1158	sendPppFrame();
nixnax	227:f87156f9ef11	1159	}
nixnax	227:f87156f9ef11	1160	break;
nixnax	227:f87156f9ef11	1161	case 2: // LCP configuration acknowledge
nixnax	230:ee097c486e45	1162	debugPuts("LCP Ack\n"); // don't do anything, i.e. ignore
nixnax	227:f87156f9ef11	1163	break;
nixnax	227:f87156f9ef11	1164	case 5: // LCP end
nixnax	227:f87156f9ef11	1165	ppp.lcp->code=6; // acknowledge
nixnax	227:f87156f9ef11	1166	sendPppFrame(); // acknowledge
nixnax	227:f87156f9ef11	1167	ppp.online=0; // start hunting for connect string again
nixnax	227:f87156f9ef11	1168	pppInitStruct(); // flush the receive buffer
nixnax	230:ee097c486e45	1169	debugPuts("LCP End (Disconnect from host)\n");
nixnax	142:54d1543e23e5	1170	break; // end connection
nixnax	142:54d1543e23e5	1171	default:
nixnax	231:6bd4523833a2	1172	debugPuts("LCP Other\n");
nixnax	142:54d1543e23e5	1173	}
nixnax	142:54d1543e23e5	1174	}
nixnax	142:54d1543e23e5	1175
nixnax	142:54d1543e23e5	1176	/// discard packets that are not IP, IPCP, or LCP
nixnax	142:54d1543e23e5	1177	void discardedFrame()
nixnax	142:54d1543e23e5	1178	{
nixnax	142:54d1543e23e5	1179	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	1180	}
nixnax	142:54d1543e23e5	1181
nixnax	142:54d1543e23e5	1182	/// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax	142:54d1543e23e5	1183	void determinePacketType()
nixnax	142:54d1543e23e5	1184	{
nixnax	167:ff8a2d8beeb1	1185	if ( ppp.ppp->address != 0xff ) {
nixnax	231:6bd4523833a2	1186	debugPuts("Unexpected: PPP address != ff\n");
nixnax	142:54d1543e23e5	1187	return;
nixnax	142:54d1543e23e5	1188	}
nixnax	167:ff8a2d8beeb1	1189	if ( ppp.ppp->control != 3 ) {
nixnax	231:6bd4523833a2	1190	debugPuts("Unexpected: PPP control != 3\n");
nixnax	142:54d1543e23e5	1191	return;
nixnax	142:54d1543e23e5	1192	}
nixnax	167:ff8a2d8beeb1	1193	unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax	167:ff8a2d8beeb1	1194	switch ( protocol ) {
nixnax	167:ff8a2d8beeb1	1195	case 0xc021:
nixnax	142:54d1543e23e5	1196	LCPframe();
nixnax	142:54d1543e23e5	1197	break; // link control
nixnax	167:ff8a2d8beeb1	1198	case 0x8021:
nixnax	142:54d1543e23e5	1199	IPCPframe();
nixnax	142:54d1543e23e5	1200	break; // IP control
nixnax	167:ff8a2d8beeb1	1201	case 0x0021:
nixnax	142:54d1543e23e5	1202	IPframe();
nixnax	142:54d1543e23e5	1203	break; // IP itself
nixnax	142:54d1543e23e5	1204	default:
nixnax	142:54d1543e23e5	1205	discardedFrame();
nixnax	142:54d1543e23e5	1206	}
nixnax	142:54d1543e23e5	1207	}
nixnax	142:54d1543e23e5	1208
nixnax	146:a45f49a2b29c	1209	/// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax	146:a45f49a2b29c	1210	void sniff()
nixnax	146:a45f49a2b29c	1211	{
nixnax	221:1d7c32d8256b	1212	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	1213	}
nixnax	146:a45f49a2b29c	1214
nixnax	142:54d1543e23e5	1215	/// scan the PPP serial input stream for frame start markers
nixnax	143:c5019f856a56	1216	void waitForPppFrame()
nixnax	142:54d1543e23e5	1217	{
nixnax	142:54d1543e23e5	1218	while(1) {
nixnax	142:54d1543e23e5	1219	if ( ppp.rx.head != ppp.rx.tail ) {
nixnax	142:54d1543e23e5	1220	int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax	142:54d1543e23e5	1221	int rx = pc_getBuf(); // get the character
nixnax	238:f39289ed5a2e	1222	if (rx==0x7e) { // check for frame start/end character 0x7e
nixnax	142:54d1543e23e5	1223	if (ppp.firstFrame) { // is this the start of the first frame start
nixnax	142:54d1543e23e5	1224	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1225	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax	181:bcfe7fe2142d	1226	ppp.firstFrame=0; // clear first frame flag
nixnax	142:54d1543e23e5	1227	} else {
nixnax	142:54d1543e23e5	1228	ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax	142:54d1543e23e5	1229	processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax	142:54d1543e23e5	1230	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1231	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax	142:54d1543e23e5	1232	break;
nixnax	142:54d1543e23e5	1233	}
nixnax	142:54d1543e23e5	1234	}
nixnax	142:54d1543e23e5	1235	}
nixnax	210:a2a651249a9a	1236	// change below to YES to enable the serial to UDP demo
nixnax	210:a2a651249a9a	1237	#define SERIAL_TO_UDP_NO
nixnax	210:a2a651249a9a	1238	#ifdef SERIAL_TO_UDP_YES
nixnax	210:a2a651249a9a	1239	sendUdpData(); // demo that sends characters received on the DEBUG serial port via UDP to another host
nixnax	210:a2a651249a9a	1240	#endif
nixnax	142:54d1543e23e5	1241	}
nixnax	142:54d1543e23e5	1242	}
nixnax	142:54d1543e23e5	1243
nixnax	209:aa514cd631ee	1244	/// 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	1245	// 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	1246	void waitForPcConnectString()
nixnax	142:54d1543e23e5	1247	{
nixnax	142:54d1543e23e5	1248	while(ppp.online == 0) {
nixnax	142:54d1543e23e5	1249	// search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax	142:54d1543e23e5	1250	char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax	142:54d1543e23e5	1251	if (found1 != NULL) {
nixnax	230:ee097c486e45	1252	if (v0) debugPuts("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax	208:73086736610a	1253	// respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax	142:54d1543e23e5	1254	pc.puts("CLIENTSERVER");
nixnax	142:54d1543e23e5	1255	ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax	142:54d1543e23e5	1256	}
nixnax	142:54d1543e23e5	1257	}
nixnax	142:54d1543e23e5	1258	}
nixnax	142:54d1543e23e5	1259
nixnax	144:01d98cf7738e	1260	/// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax	144:01d98cf7738e	1261	void initializePpp()
nixnax	142:54d1543e23e5	1262	{
nixnax	210:a2a651249a9a	1263	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	144:01d98cf7738e	1264	debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax	230:ee097c486e45	1265	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	1266	wait_ms(200); // a brief wait so a human can see the reset event
nixnax	230:ee097c486e45	1267	debugPuts("mbed PPP-Blinky HTTP & WebSocket server ready :)\n");
nixnax	210:a2a651249a9a	1268	#endif
nixnax	179:ba2b2ddd0da5	1269	pppInitStruct(); // initialize all the variables/properties/buffers
nixnax	179:ba2b2ddd0da5	1270	pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
nixnax	179:ba2b2ddd0da5	1271	pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
nixnax	143:c5019f856a56	1272	}

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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.