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@243:24f899297799, 2018-12-07 (annotated)

Committer:: nixnax
Date:: Fri Dec 07 07:11:00 2018 +0000
Revision:: 243:24f899297799
Parent:: 242:1e9215c09da5
Child:: 245:544cea761769

Trap buffer full event with LED flashing

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	243:24f899297799	214	#define BUFFER_FULL_TRAP_NO
nixnax	243:24f899297799	215	#ifdef BUFFER_FULL_TRAP_YES
nixnax	243:24f899297799	216	while(1) {
nixnax	243:24f899297799	217	led1Toggle(); // flash LED at a slow rate to indicate buffer overfloe
nixnax	243:24f899297799	218	wait_ms(150);
nixnax	243:24f899297799	219	}
nixnax	243:24f899297799	220	#elseif
nixnax	221:1d7c32d8256b	221	return; // don't read if rx buffer is full
nixnax	243:24f899297799	222	#endif
nixnax	142:54d1543e23e5	223	}
nixnax	142:54d1543e23e5	224	ch = pc.getc(); // read new character
nixnax	142:54d1543e23e5	225	ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax	209:aa514cd631ee	226	if (ch == 0x7E) { // check for ppp frame start character
nixnax	209:aa514cd631ee	227	if ( ppp.online == 0 ) { // check if we are offline
nixnax	209:aa514cd631ee	228	ppp.online = 1; // if we see a frame start character we immediately change status to online
nixnax	142:54d1543e23e5	229	}
nixnax	142:54d1543e23e5	230	}
nixnax	223:917b554cb8a5	231	ppp.rx.head = localHead; // update real head pointer
nixnax	221:1d7c32d8256b	232	ppp.rx.buflevel++; // update buffer level counter
nixnax	209:aa514cd631ee	233	if ( ppp.rx.buflevel > ppp.rx.maxbuflevel ) {
nixnax	221:1d7c32d8256b	234	ppp.rx.maxbuflevel = ppp.rx.buflevel; // remember the maximum usage of rx buffer
nixnax	209:aa514cd631ee	235	}
nixnax	142:54d1543e23e5	236	}
nixnax	142:54d1543e23e5	237	}
nixnax	142:54d1543e23e5	238
nixnax	145:098b6ed2f7f2	239	/// update the cumulative PPP FCS (frame check sequence)
nixnax	226:4898247048c7	240	void fcsDo(register int x)
nixnax	142:54d1543e23e5	241	{
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	220:54f45f924707	249	x>>=1;
nixnax	230:ee097c486e45	250	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	251	x>>=1;
nixnax	230:ee097c486e45	252	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	253	x>>=1;
nixnax	230:ee097c486e45	254	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	255	x>>=1;
nixnax	230:ee097c486e45	256	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	142:54d1543e23e5	257	}
nixnax	142:54d1543e23e5	258
nixnax	145:098b6ed2f7f2	259	/// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax	145:098b6ed2f7f2	260	int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax	142:54d1543e23e5	261	{
nixnax	226:4898247048c7	262	ppp.fcs=0xffff; // fcs initial value
nixnax	145:098b6ed2f7f2	263	for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax	145:098b6ed2f7f2	264	return ppp.fcs;
nixnax	142:54d1543e23e5	265	}
nixnax	142:54d1543e23e5	266
nixnax	142:54d1543e23e5	267	/// Get one character from our received PPP buffer
nixnax	142:54d1543e23e5	268	int pc_getBuf()
nixnax	142:54d1543e23e5	269	{
nixnax	142:54d1543e23e5	270	int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax	230:ee097c486e45	271	int temptail = ppp.rx.tail+1;
nixnax	230:ee097c486e45	272	if (temptail > RXBUFLEN) temptail=0;
nixnax	142:54d1543e23e5	273	ppp.rx.buflevel--;
nixnax	230:ee097c486e45	274	ppp.rx.tail = temptail;
nixnax	142:54d1543e23e5	275	return x;
nixnax	142:54d1543e23e5	276	}
nixnax	142:54d1543e23e5	277
nixnax	142:54d1543e23e5	278	/// Dump a PPP frame to the debug serial port
nixnax	142:54d1543e23e5	279	/// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax	142:54d1543e23e5	280	/// Capture the frame's hex output in your terminal program and save as a text file
nixnax	164:c3de3d212c4b	281	/// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax	142:54d1543e23e5	282	void dumpPPPFrame()
nixnax	142:54d1543e23e5	283	{
nixnax	230:ee097c486e45	284	char pbuf[100];
nixnax	142:54d1543e23e5	285	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	210:a2a651249a9a	286
nixnax	142:54d1543e23e5	287	sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax	210:a2a651249a9a	288
nixnax	221:1d7c32d8256b	289	debugPuts(pbuf);
nixnax	142:54d1543e23e5	290	}
nixnax	210:a2a651249a9a	291
nixnax	142:54d1543e23e5	292	sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax	210:a2a651249a9a	293
nixnax	221:1d7c32d8256b	294	debugPuts(pbuf);
nixnax	142:54d1543e23e5	295	}
nixnax	142:54d1543e23e5	296
nixnax	142:54d1543e23e5	297	/// Process a received PPP frame
nixnax	142:54d1543e23e5	298	void processPPPFrame(int start, int end)
nixnax	142:54d1543e23e5	299	{
nixnax	226:4898247048c7	300	led1Toggle(); // change led1 state on received frames
nixnax	142:54d1543e23e5	301	if(start==end) {
nixnax	142:54d1543e23e5	302	return; // empty frame
nixnax	142:54d1543e23e5	303	}
nixnax	226:4898247048c7	304	ppp.fcs=0xffff; // fcs initial value
nixnax	142:54d1543e23e5	305	char * dest = ppp.pkt.buf;
nixnax	142:54d1543e23e5	306	ppp.pkt.len=0;
nixnax	142:54d1543e23e5	307	int unstuff=0;
nixnax	142:54d1543e23e5	308	int idx = start;
nixnax	142:54d1543e23e5	309	while(1) {
nixnax	142:54d1543e23e5	310	if (unstuff==0) {
nixnax	142:54d1543e23e5	311	if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax	142:54d1543e23e5	312	else {
nixnax	142:54d1543e23e5	313	*dest = ppp.rx.buf[idx];
nixnax	142:54d1543e23e5	314	ppp.pkt.len++;
nixnax	142:54d1543e23e5	315	dest++;
nixnax	145:098b6ed2f7f2	316	fcsDo(ppp.rx.buf[idx]);
nixnax	142:54d1543e23e5	317	}
nixnax	142:54d1543e23e5	318	} else { // unstuff characters prefixed with 0x7d
nixnax	142:54d1543e23e5	319	*dest = ppp.rx.buf[idx]^0x20;
nixnax	142:54d1543e23e5	320	ppp.pkt.len++;
nixnax	142:54d1543e23e5	321	dest++;
nixnax	145:098b6ed2f7f2	322	fcsDo(ppp.rx.buf[idx]^0x20);
nixnax	142:54d1543e23e5	323	unstuff=0;
nixnax	142:54d1543e23e5	324	}
nixnax	216:e3c5a5b47295	325	idx = idx+1;
nixnax	216:e3c5a5b47295	326	if (idx > RXBUFLEN) idx=0;
nixnax	142:54d1543e23e5	327	if (idx == end) break;
nixnax	142:54d1543e23e5	328	}
nixnax	145:098b6ed2f7f2	329	ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax	226:4898247048c7	330	#ifdef DUMP_RECEIVED_PPP_FRAMES_YES
nixnax	226:4898247048c7	331	dumpPPPFrame(); // hex dump ALL ppp frames to the debug port
nixnax	226:4898247048c7	332	#endif
nixnax	142:54d1543e23e5	333	if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax	142:54d1543e23e5	334	determinePacketType();
nixnax	142:54d1543e23e5	335	} else {
nixnax	142:54d1543e23e5	336	#define REPORT_FCS_ERROR_YES
nixnax	142:54d1543e23e5	337	#ifdef REPORT_FCS_ERROR_YES
nixnax	230:ee097c486e45	338	char pbuf[100]; // local print buffer
nixnax	142:54d1543e23e5	339	sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax	221:1d7c32d8256b	340	debugPuts( pbuf );
nixnax	226:4898247048c7	341	#define DUMP_PPP_FRAME_ON_ERROR_NO
nixnax	226:4898247048c7	342	#ifdef DUMP_PPP_FRAME_ON_ERROR_YES
nixnax	226:4898247048c7	343	dumpPPPFrame(); // dump frames with errors in them
nixnax	226:4898247048c7	344	#endif
nixnax	142:54d1543e23e5	345	#endif
nixnax	142:54d1543e23e5	346	}
nixnax	142:54d1543e23e5	347	}
nixnax	142:54d1543e23e5	348
nixnax	142:54d1543e23e5	349	/// do PPP HDLC-like handling of special (flag) characters
nixnax	143:c5019f856a56	350	void hdlcPut(int ch)
nixnax	142:54d1543e23e5	351	{
nixnax	242:1e9215c09da5	352	if ( (ch<0x20) \|\| (ch==0x7d) \|\| (ch==0x7e) \|\| (ch>0x7f) ) {
nixnax	226:4898247048c7	353	pc.putc(0x7d);
nixnax	226:4898247048c7	354	pc.putc(ch^0x20); // these characters need special handling
nixnax	142:54d1543e23e5	355	} else {
nixnax	226:4898247048c7	356	pc.putc(ch);
nixnax	142:54d1543e23e5	357	}
nixnax	142:54d1543e23e5	358	}
nixnax	142:54d1543e23e5	359
nixnax	142:54d1543e23e5	360	/// send a PPP frame in HDLC format
nixnax	144:01d98cf7738e	361	void sendPppFrame()
nixnax	143:c5019f856a56	362	{
nixnax	172:449dd7a28955	363	ppp.responseCounter++; // count the number of ppp frames we send
nixnax	145:098b6ed2f7f2	364	int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax	142:54d1543e23e5	365	ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax	142:54d1543e23e5	366	ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax	226:4898247048c7	367	pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax	142:54d1543e23e5	368	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	226:4898247048c7	369	// wait_us(86); // wait one character time
nixnax	210:a2a651249a9a	370
nixnax	142:54d1543e23e5	371	hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax	142:54d1543e23e5	372	}
nixnax	226:4898247048c7	373	pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax	142:54d1543e23e5	374	}
nixnax	142:54d1543e23e5	375
nixnax	143:c5019f856a56	376	/// 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	377	int bufferToIP(char * buffer)
nixnax	143:c5019f856a56	378	{
nixnax	143:c5019f856a56	379	int result=0;
nixnax	143:c5019f856a56	380	for(int i=0; i<4; i++) result = (result<<8)\|(*buffer++ & 0xff);
nixnax	143:c5019f856a56	381	return result;
nixnax	143:c5019f856a56	382	}
nixnax	143:c5019f856a56	383
nixnax	177:dab9e685af53	384	/// convert 4-byte ip address to 32-bit
nixnax	228:7fb878500862	385	unsigned int integersToIp( int a, int b, int c, int d)
nixnax	179:ba2b2ddd0da5	386	{
nixnax	177:dab9e685af53	387	return a<<24 \| b<<16 \| c<<8 \| d;
nixnax	177:dab9e685af53	388	}
nixnax	177:dab9e685af53	389
nixnax	142:54d1543e23e5	390	/// handle IPCP configuration requests
nixnax	142:54d1543e23e5	391	void ipcpConfigRequestHandler()
nixnax	142:54d1543e23e5	392	{
nixnax	230:ee097c486e45	393	debugPuts("Their IPCP Config Req, Our Ack\n");
nixnax	173:6774a0c851c4	394	if(ppp.ipcp->request[0]==3) {
nixnax	143:c5019f856a56	395	ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax	173:6774a0c851c4	396	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	397	}
nixnax	143:c5019f856a56	398
nixnax	167:ff8a2d8beeb1	399	ppp.ipcp->code=2; // change code to ack
nixnax	144:01d98cf7738e	400	sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax	142:54d1543e23e5	401
nixnax	230:ee097c486e45	402	debugPuts("Our IPCP Ask (no options)\n");
nixnax	167:ff8a2d8beeb1	403	ppp.ipcp->code=1; // change code to request
nixnax	167:ff8a2d8beeb1	404	ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax	167:ff8a2d8beeb1	405	ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax	144:01d98cf7738e	406	sendPppFrame(); // send our request
nixnax	142:54d1543e23e5	407	}
nixnax	142:54d1543e23e5	408
nixnax	142:54d1543e23e5	409	/// handle IPCP acknowledge (do nothing)
nixnax	142:54d1543e23e5	410	void ipcpAckHandler()
nixnax	142:54d1543e23e5	411	{
nixnax	230:ee097c486e45	412	debugPuts("Their IPCP Grant\n");
nixnax	142:54d1543e23e5	413	}
nixnax	142:54d1543e23e5	414
nixnax	143:c5019f856a56	415	/// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax	143:c5019f856a56	416	/// 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	417	void ipcpNackHandler()
nixnax	142:54d1543e23e5	418	{
nixnax	230:ee097c486e45	419	debugPuts("Their IPCP Nack\n");
nixnax	173:6774a0c851c4	420	if (ppp.ipcp->request[0]==3) { // check if the NACK contains an IP address parameter
nixnax	167:ff8a2d8beeb1	421	ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax	144:01d98cf7738e	422	sendPppFrame(); // let's request this IP address as ours
nixnax	230:ee097c486e45	423	debugPuts("Our IPCP ACK (received an IP)\n");
nixnax	146:a45f49a2b29c	424	} else { // if it's not an IP nack we ignore it
nixnax	230:ee097c486e45	425	debugPuts("IPCP Nack Ignored\n");
nixnax	146:a45f49a2b29c	426	}
nixnax	142:54d1543e23e5	427	}
nixnax	142:54d1543e23e5	428
nixnax	142:54d1543e23e5	429	/// handle all other IPCP requests (by ignoring them)
nixnax	142:54d1543e23e5	430	void ipcpDefaultHandler()
nixnax	142:54d1543e23e5	431	{
nixnax	230:ee097c486e45	432	debugPuts("Their IPCP Other\n");
nixnax	142:54d1543e23e5	433	}
nixnax	142:54d1543e23e5	434
nixnax	142:54d1543e23e5	435	/// process an incoming IPCP packet
nixnax	142:54d1543e23e5	436	void IPCPframe()
nixnax	142:54d1543e23e5	437	{
nixnax	167:ff8a2d8beeb1	438	int action = ppp.ipcp->code; // packet type is here
nixnax	167:ff8a2d8beeb1	439	switch (action) {
nixnax	142:54d1543e23e5	440	case 1:
nixnax	142:54d1543e23e5	441	ipcpConfigRequestHandler();
nixnax	142:54d1543e23e5	442	break;
nixnax	142:54d1543e23e5	443	case 2:
nixnax	142:54d1543e23e5	444	ipcpAckHandler();
nixnax	142:54d1543e23e5	445	break;
nixnax	142:54d1543e23e5	446	case 3:
nixnax	142:54d1543e23e5	447	ipcpNackHandler();
nixnax	142:54d1543e23e5	448	break;
nixnax	142:54d1543e23e5	449	default:
nixnax	142:54d1543e23e5	450	ipcpDefaultHandler();
nixnax	142:54d1543e23e5	451	}
nixnax	142:54d1543e23e5	452	}
nixnax	142:54d1543e23e5	453
nixnax	142:54d1543e23e5	454	/// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax	161:d59f778bc8ab	455	unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax	142:54d1543e23e5	456	{
nixnax	159:4d1bf96a59cd	457	unsigned int i,hi,lo;
nixnax	142:54d1543e23e5	458	unsigned char placeHolder;
nixnax	161:d59f778bc8ab	459	if (restart) ppp.sum=0;
nixnax	142:54d1543e23e5	460	if (len&1) {
nixnax	142:54d1543e23e5	461	placeHolder = ptr[len];
nixnax	142:54d1543e23e5	462	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	463	}
nixnax	142:54d1543e23e5	464	i=0;
nixnax	142:54d1543e23e5	465	while ( i<len ) {
nixnax	210:a2a651249a9a	466
nixnax	142:54d1543e23e5	467	hi = ptr[i++];
nixnax	142:54d1543e23e5	468	lo = ptr[i++];
nixnax	159:4d1bf96a59cd	469	ppp.sum = ppp.sum + ((hi<<8)\|lo);
nixnax	142:54d1543e23e5	470	}
nixnax	142:54d1543e23e5	471	if (len&1) {
nixnax	142:54d1543e23e5	472	ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax	142:54d1543e23e5	473	}
nixnax	159:4d1bf96a59cd	474	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax	159:4d1bf96a59cd	475	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax	159:4d1bf96a59cd	476	return ~ppp.sum;
nixnax	142:54d1543e23e5	477	}
nixnax	142:54d1543e23e5	478
nixnax	142:54d1543e23e5	479	/// perform the checksum on an IP header
nixnax	146:a45f49a2b29c	480	void IpHeaderCheckSum()
nixnax	142:54d1543e23e5	481	{
nixnax	161:d59f778bc8ab	482	ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax	161:d59f778bc8ab	483	int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax	161:d59f778bc8ab	484	unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax	161:d59f778bc8ab	485	ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax	146:a45f49a2b29c	486	}
nixnax	146:a45f49a2b29c	487
nixnax	147:0f40005cbc5f	488	/// swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	489	void swapIpAddresses()
nixnax	147:0f40005cbc5f	490	{
nixnax	162:594729c0e5c1	491	unsigned int tempHold;
nixnax	162:594729c0e5c1	492	tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax	162:594729c0e5c1	493	ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax	162:594729c0e5c1	494	ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax	147:0f40005cbc5f	495	}
nixnax	147:0f40005cbc5f	496
nixnax	149:969d98f6fb88	497	/// swap the IP source and destination ports
nixnax	149:969d98f6fb88	498	void swapIpPorts()
nixnax	149:969d98f6fb88	499	{
nixnax	173:6774a0c851c4	500	int headerSizeIP = 4 * (ppp.ip->headerLength); // calculate size of IP header
nixnax	173:6774a0c851c4	501	char * ipSrcPort = ppp.ipStart + headerSizeIP + 0; // ip source port location
nixnax	173:6774a0c851c4	502	char * ipDstPort = ppp.ipStart + headerSizeIP + 2; // ip destin port location
nixnax	149:969d98f6fb88	503	char tempHold[2];
nixnax	149:969d98f6fb88	504	memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax	149:969d98f6fb88	505	memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax	149:969d98f6fb88	506	memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax	149:969d98f6fb88	507	}
nixnax	149:969d98f6fb88	508
nixnax	170:3d3b2126181c	509	/// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax	170:3d3b2126181c	510	void checkSumPseudoHeader( unsigned int packetLength )
nixnax	170:3d3b2126181c	511	{
nixnax	170:3d3b2126181c	512	// 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	513	pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax	170:3d3b2126181c	514	pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax	170:3d3b2126181c	515	pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax	170:3d3b2126181c	516	pseudoHeader.zero = 0; // zero byte
nixnax	170:3d3b2126181c	517	pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax	170:3d3b2126181c	518	pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax	170:3d3b2126181c	519	dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax	170:3d3b2126181c	520	}
nixnax	170:3d3b2126181c	521
nixnax	171:46b36d4edd1d	522	/// initialize an IP packet to send
nixnax	171:46b36d4edd1d	523	void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax	171:46b36d4edd1d	524	{
nixnax	171:46b36d4edd1d	525	ppp.ppp->address = 0xff;
nixnax	171:46b36d4edd1d	526	ppp.ppp->control = 3;
nixnax	171:46b36d4edd1d	527	ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax	171:46b36d4edd1d	528	ppp.ip->version = 4;
nixnax	171:46b36d4edd1d	529	ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax	171:46b36d4edd1d	530	ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax	171:46b36d4edd1d	531	ppp.ip->dontFragment=1;
nixnax	171:46b36d4edd1d	532	ppp.ip->ttl=128;
nixnax	171:46b36d4edd1d	533	ppp.ip->protocol = protocol; // udp
nixnax	171:46b36d4edd1d	534	ppp.ip->srcAdrR = __REV(srcIp);
nixnax	171:46b36d4edd1d	535	ppp.ip->dstAdrR = __REV(dstIp);
nixnax	171:46b36d4edd1d	536	ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax	171:46b36d4edd1d	537	ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax	171:46b36d4edd1d	538	ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax	171:46b36d4edd1d	539	}
nixnax	171:46b36d4edd1d	540
nixnax	171:46b36d4edd1d	541
nixnax	171:46b36d4edd1d	542	/// Build a UDP packet from scratch
nixnax	171:46b36d4edd1d	543	void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax	171:46b36d4edd1d	544	{
nixnax	171:46b36d4edd1d	545	struct {
nixnax	171:46b36d4edd1d	546	unsigned int ipAll; // length of entire ip packet
nixnax	171:46b36d4edd1d	547	unsigned int ipHeader; // length of ip header
nixnax	171:46b36d4edd1d	548	unsigned int udpAll; // length of entire udp packet
nixnax	171:46b36d4edd1d	549	unsigned int udpData; // length of udp data segment
nixnax	171:46b36d4edd1d	550	} len;
nixnax	171:46b36d4edd1d	551	len.ipHeader = 20; // ip header length
nixnax	171:46b36d4edd1d	552	len.udpData = msgLen; // udp data size
nixnax	171:46b36d4edd1d	553	len.udpAll = len.udpData+8; // update local udp packet length
nixnax	171:46b36d4edd1d	554	len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax	171:46b36d4edd1d	555	initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax	171:46b36d4edd1d	556	ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax	171:46b36d4edd1d	557	ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax	171:46b36d4edd1d	558	memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax	171:46b36d4edd1d	559	ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax	171:46b36d4edd1d	560	ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	561	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	562	checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	563	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	564	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	565	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	566	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	567	}
nixnax	171:46b36d4edd1d	568
nixnax	146:a45f49a2b29c	569	/// Process an incoming UDP packet.
nixnax	146:a45f49a2b29c	570	/// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax	146:a45f49a2b29c	571	void UDPpacket()
nixnax	146:a45f49a2b29c	572	{
nixnax	163:d1b4328e9f08	573	struct {
nixnax	163:d1b4328e9f08	574	unsigned int all; // length of entire ip packet
nixnax	163:d1b4328e9f08	575	unsigned int header; // length of ip header
nixnax	163:d1b4328e9f08	576	} ipLength;
nixnax	163:d1b4328e9f08	577
nixnax	163:d1b4328e9f08	578	struct {
nixnax	165:c47826d07e0d	579	unsigned int all; // length of entire udp packet
nixnax	163:d1b4328e9f08	580	unsigned int data; // length of udp data segment
nixnax	163:d1b4328e9f08	581	} udpLength;
nixnax	163:d1b4328e9f08	582
nixnax	163:d1b4328e9f08	583	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	163:d1b4328e9f08	584	ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	171:46b36d4edd1d	585	udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax	163:d1b4328e9f08	586	udpLength.data = udpLength.all - 8; // size of udp data
nixnax	147:0f40005cbc5f	587
nixnax	146:a45f49a2b29c	588	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	171:46b36d4edd1d	589	char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax	171:46b36d4edd1d	590	char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax	163:d1b4328e9f08	591
nixnax	171:46b36d4edd1d	592	unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax	171:46b36d4edd1d	593	unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax	163:d1b4328e9f08	594
nixnax	163:d1b4328e9f08	595	if(v0) {
nixnax	163:d1b4328e9f08	596	debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax	163:d1b4328e9f08	597	debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax	163:d1b4328e9f08	598	debugPrintf("Len %03d", udpLength);
nixnax	163:d1b4328e9f08	599	}
nixnax	146:a45f49a2b29c	600	if (v1) {
nixnax	163:d1b4328e9f08	601	int printSize = udpLength.data;
nixnax	146:a45f49a2b29c	602	if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax	146:a45f49a2b29c	603	for (int i=0; i<printSize; i++) {
nixnax	163:d1b4328e9f08	604	char ch = ppp.udp->data[i];
nixnax	146:a45f49a2b29c	605	if (ch>31 && ch<127) {
nixnax	146:a45f49a2b29c	606	debugPrintf("%c", ch);
nixnax	146:a45f49a2b29c	607	} else {
nixnax	230:ee097c486e45	608	debugPuts("_");
nixnax	146:a45f49a2b29c	609	}
nixnax	146:a45f49a2b29c	610	}
nixnax	146:a45f49a2b29c	611	}
nixnax	230:ee097c486e45	612	if (v0) debugPuts("\n");
nixnax	146:a45f49a2b29c	613	#endif
nixnax	163:d1b4328e9f08	614	int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax	163:d1b4328e9f08	615	int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax	146:a45f49a2b29c	616	if ( (echoFound) \|\| (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax	146:a45f49a2b29c	617	if (echoFound) {
nixnax	171:46b36d4edd1d	618	swapIpAddresses(); // swap IP source and destination
nixnax	171:46b36d4edd1d	619	swapIpPorts(); // swap IP source and destination ports
nixnax	163:d1b4328e9f08	620	memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax	170:3d3b2126181c	621	int n=0;
nixnax	230:ee097c486e45	622	#define IDENTIFY_UDP_SERVER_NO
nixnax	230:ee097c486e45	623	#ifdef IDENTIFY_UDP_SERVER_YES
nixnax	170:3d3b2126181c	624	n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax	230:ee097c486e45	625	#endif
nixnax	168:c77eb908042a	626	udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax	171:46b36d4edd1d	627	// we may have changed data length, update all the lengths
nixnax	171:46b36d4edd1d	628	udpLength.all = udpLength.data+8; // update local udp packet length
nixnax	171:46b36d4edd1d	629	ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax	171:46b36d4edd1d	630	ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax	171:46b36d4edd1d	631	ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax	171:46b36d4edd1d	632	ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	633	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	634	checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	635	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	636	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	637	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	638	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	639	} else if ( testFound ) {
nixnax	171:46b36d4edd1d	640	unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax	171:46b36d4edd1d	641	unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax	171:46b36d4edd1d	642	unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax	171:46b36d4edd1d	643	unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax	172:449dd7a28955	644	int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter);
nixnax	171:46b36d4edd1d	645	sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax	146:a45f49a2b29c	646	}
nixnax	146:a45f49a2b29c	647	}
nixnax	142:54d1543e23e5	648	}
nixnax	142:54d1543e23e5	649
nixnax	174:e5a3f16421a5	650	/// UDP demo that sends a udp packet containing a character received from the second debug serial port.
nixnax	174:e5a3f16421a5	651	/// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
nixnax	178:3f17aa0ce5ce	652	/// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
nixnax	178:3f17aa0ce5ce	653	/// See http://www.wikihow.com/Enable-IP-Routing.
nixnax	179:ba2b2ddd0da5	654	/// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
nixnax	179:ba2b2ddd0da5	655	/// The netcat UDP receive command on the remote host would be: nc -ul 12345
nixnax	174:e5a3f16421a5	656	void sendUdpData()
nixnax	174:e5a3f16421a5	657	{
nixnax	174:e5a3f16421a5	658	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	179:ba2b2ddd0da5	659	if (ppp.online) {
nixnax	179:ba2b2ddd0da5	660	if (xx.readable()) {
nixnax	179:ba2b2ddd0da5	661	char inchar = xx.getc();
nixnax	179:ba2b2ddd0da5	662	xx.putc( inchar ); // echo the received character on the debug serial port
nixnax	228:7fb878500862	663	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	664	}
nixnax	174:e5a3f16421a5	665	}
nixnax	174:e5a3f16421a5	666	#endif
nixnax	174:e5a3f16421a5	667	}
nixnax	174:e5a3f16421a5	668
nixnax	142:54d1543e23e5	669	/// handle a PING ICMP (internet control message protocol) packet
nixnax	142:54d1543e23e5	670	void ICMPpacket() // internet control message protocol
nixnax	142:54d1543e23e5	671	{
nixnax	165:c47826d07e0d	672	struct {
nixnax	165:c47826d07e0d	673	unsigned int all; // length of entire ip packet
nixnax	165:c47826d07e0d	674	unsigned int header; // length of ip header
nixnax	165:c47826d07e0d	675	} ipLength;
nixnax	165:c47826d07e0d	676	struct {
nixnax	165:c47826d07e0d	677	unsigned int all; // length of entire udp packet
nixnax	165:c47826d07e0d	678	unsigned int data; // length of udp data segment
nixnax	165:c47826d07e0d	679	} icmpLength;
nixnax	165:c47826d07e0d	680	ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax	165:c47826d07e0d	681	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	165:c47826d07e0d	682	ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	165:c47826d07e0d	683	icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax	165:c47826d07e0d	684	icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax	142:54d1543e23e5	685	#define ICMP_TYPE_PING_REQUEST 8
nixnax	165:c47826d07e0d	686	if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax	165:c47826d07e0d	687	ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax	239:426e50519204	688	ppp.pingCount++; // count how many times we get pinged
nixnax	147:0f40005cbc5f	689	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	167:ff8a2d8beeb1	690	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	691	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	165:c47826d07e0d	692	int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax	165:c47826d07e0d	693	int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax	142:54d1543e23e5	694	if(1) {
nixnax	230:ee097c486e45	695	char pbuf[100];
nixnax	210:a2a651249a9a	696
nixnax	142:54d1543e23e5	697	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	698	debugPuts( pbuf );
nixnax	210:a2a651249a9a	699
nixnax	142:54d1543e23e5	700	sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax	210:a2a651249a9a	701
nixnax	221:1d7c32d8256b	702	debugPuts( pbuf );
nixnax	142:54d1543e23e5	703	}
nixnax	142:54d1543e23e5	704	#endif
nixnax	147:0f40005cbc5f	705	swapIpAddresses(); // swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	706	IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax	142:54d1543e23e5	707	#define ICMP_TYPE_ECHO_REPLY 0
nixnax	165:c47826d07e0d	708	ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax	165:c47826d07e0d	709	ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax	165:c47826d07e0d	710	unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax	165:c47826d07e0d	711	ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax	226:4898247048c7	712	#define DUMP_ICMP_PACKETS_NO
nixnax	226:4898247048c7	713	#ifdef DUMP_ICMP_PACKETS_YES
nixnax	165:c47826d07e0d	714	int printSize = icmpLength.data; // exclude size of icmp header
nixnax	142:54d1543e23e5	715	if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax	226:4898247048c7	716	for (int i=0; i<printSize; i++) {
nixnax	226:4898247048c7	717	char ch = ppp.icmp->data[i];
nixnax	226:4898247048c7	718	if (ch>31 && ch<127) {
nixnax	226:4898247048c7	719	debugPutc(ch);
nixnax	226:4898247048c7	720	} else {
nixnax	226:4898247048c7	721	debugPutc('_'); // for non-printable characters
nixnax	142:54d1543e23e5	722	}
nixnax	142:54d1543e23e5	723	}
nixnax	226:4898247048c7	724	debugPutc('\n');
nixnax	226:4898247048c7	725	#endif
nixnax	144:01d98cf7738e	726	sendPppFrame(); // reply to the ping
nixnax	142:54d1543e23e5	727	} else {
nixnax	142:54d1543e23e5	728	if (v0) {
nixnax	165:c47826d07e0d	729	debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax	142:54d1543e23e5	730	}
nixnax	142:54d1543e23e5	731	}
nixnax	142:54d1543e23e5	732	}
nixnax	142:54d1543e23e5	733
nixnax	142:54d1543e23e5	734	/// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax	142:54d1543e23e5	735	void IGMPpacket()
nixnax	142:54d1543e23e5	736	{
nixnax	142:54d1543e23e5	737	if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax	142:54d1543e23e5	738	}
nixnax	142:54d1543e23e5	739
nixnax	142:54d1543e23e5	740	/// dump the header of an IP pakcet on the (optional) debug serial port
nixnax	142:54d1543e23e5	741	void dumpHeaderIP (int outGoing)
nixnax	142:54d1543e23e5	742	{
nixnax	142:54d1543e23e5	743	#if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	210:a2a651249a9a	744
nixnax	155:9c6a1d249e26	745	int IPv4Id = __REV16(ppp.ip->identR);
nixnax	230:ee097c486e45	746	char pbuf[100]; // local print buffer
nixnax	142:54d1543e23e5	747	int n=0;
nixnax	142:54d1543e23e5	748	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	142:54d1543e23e5	749	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	750	#define DUMP_FULL_IP_ADDRESS_YES
nixnax	142:54d1543e23e5	751	#ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax	167:ff8a2d8beeb1	752	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	753	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	142:54d1543e23e5	754	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	755	#endif
nixnax	221:1d7c32d8256b	756	debugPuts( pbuf );
nixnax	142:54d1543e23e5	757	#ifndef TCP_HEADER_DUMP_YES
nixnax	221:1d7c32d8256b	758	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	759	#endif
nixnax	142:54d1543e23e5	760	#endif
nixnax	142:54d1543e23e5	761	}
nixnax	142:54d1543e23e5	762
nixnax	142:54d1543e23e5	763	/// dump a TCP header on the optional debug serial port
nixnax	142:54d1543e23e5	764	void dumpHeaderTCP(int outGoing)
nixnax	142:54d1543e23e5	765	{
nixnax	142:54d1543e23e5	766	#if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	155:9c6a1d249e26	767	char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax	142:54d1543e23e5	768	#define PRINT_ALL_TCP_FLAGS_YES
nixnax	142:54d1543e23e5	769	#ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax	155:9c6a1d249e26	770	memset(flagString,'.', 8); // fill string with "........"
nixnax	156:163c23249731	771	if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax	156:163c23249731	772	if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax	156:163c23249731	773	if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax	156:163c23249731	774	if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax	156:163c23249731	775	if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax	156:163c23249731	776	if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax	156:163c23249731	777	if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax	156:163c23249731	778	if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax	155:9c6a1d249e26	779	flagString[8]=0; // null terminate string
nixnax	142:54d1543e23e5	780	#else
nixnax	156:163c23249731	781	if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax	156:163c23249731	782	if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax	156:163c23249731	783	if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax	156:163c23249731	784	if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax	156:163c23249731	785	if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax	155:9c6a1d249e26	786	flagString[1]=0; // null terminate string
nixnax	142:54d1543e23e5	787	#endif
nixnax	221:1d7c32d8256b	788	debugPuts( flagString );
nixnax	142:54d1543e23e5	789	#define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	142:54d1543e23e5	790	#ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	221:1d7c32d8256b	791	debugPuts("\x1b[30m\n"); // write a black color and newline after every packet
nixnax	160:bd701ad564cb	792	#else
nixnax	221:1d7c32d8256b	793	debugPuts("\x1b[30m"); // write a black color after every packet
nixnax	142:54d1543e23e5	794	#endif
nixnax	156:163c23249731	795	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	796	debugPutc('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax	142:54d1543e23e5	797	}
nixnax	142:54d1543e23e5	798	#endif
nixnax	142:54d1543e23e5	799	}
nixnax	142:54d1543e23e5	800
nixnax	143:c5019f856a56	801	/// Encode a buffer in base-64
nixnax	184:4133f557d4d4	802	const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax	142:54d1543e23e5	803	void enc64(char * in, char * out, int len)
nixnax	142:54d1543e23e5	804	{
nixnax	142:54d1543e23e5	805	int i,j,a,b,c;
nixnax	142:54d1543e23e5	806	i=0;
nixnax	142:54d1543e23e5	807	j=0;
nixnax	142:54d1543e23e5	808	while(1) {
nixnax	142:54d1543e23e5	809	if (i<len) {
nixnax	142:54d1543e23e5	810	a = in[i++];
nixnax	142:54d1543e23e5	811	out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax	142:54d1543e23e5	812	} else break;
nixnax	142:54d1543e23e5	813	if (i<len) {
nixnax	142:54d1543e23e5	814	b = in[i++];
nixnax	142:54d1543e23e5	815	out[j++] = lut[ ( (a << 4) & 0x30) \| ( (b >> 4) & 0x0f) ];
nixnax	142:54d1543e23e5	816	out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax	142:54d1543e23e5	817	} else out[j++] = '=';
nixnax	142:54d1543e23e5	818	if (i<len) {
nixnax	142:54d1543e23e5	819	c = in[i++];
nixnax	142:54d1543e23e5	820	j--;
nixnax	142:54d1543e23e5	821	out[j++] = lut[ ( (b << 2) & 0x3c) \| ( (c >> 6) & 0x03) ];
nixnax	142:54d1543e23e5	822	out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax	142:54d1543e23e5	823	} else out[j++] = '=';
nixnax	142:54d1543e23e5	824	}
nixnax	142:54d1543e23e5	825	out[j]=0;
nixnax	142:54d1543e23e5	826	}
nixnax	142:54d1543e23e5	827
nixnax	160:bd701ad564cb	828	/// Handle a request for an http websocket.
nixnax	160:bd701ad564cb	829	/// 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	830	int webSocketHandler(char * dataStart)
nixnax	142:54d1543e23e5	831	{
nixnax	142:54d1543e23e5	832	int n=0; // byte counter
nixnax	184:4133f557d4d4	833	char * key = strstr(dataStart, "Sec-WebSocket-Key:"); // search for the key in the payload
nixnax	142:54d1543e23e5	834	if (key != NULL) {
nixnax	184:4133f557d4d4	835	key = key + 18; // skip over the key ident string "Sec-WebSocket-Key:"
nixnax	221:1d7c32d8256b	836	if (v0) debugPuts("WebSocket Request\n");
nixnax	184:4133f557d4d4	837	while ( strchr(lut, *key) == NULL) key++; // skip non-valid base-64 characters (whitespace)
nixnax	184:4133f557d4d4	838	char challenge [80];
nixnax	184:4133f557d4d4	839	int i=0;
nixnax	184:4133f557d4d4	840	char * copyTo = challenge;
nixnax	184:4133f557d4d4	841	while (strchr(lut, *key) != NULL) { // copy while we see valid base-64 characters
nixnax	184:4133f557d4d4	842	if (i++ >40) break; // prevent buffer overflow
nixnax	184:4133f557d4d4	843	copyTo++ = key++; // copy next valid base-64 character
nixnax	184:4133f557d4d4	844	}
nixnax	184:4133f557d4d4	845	strcpy(copyTo,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // append websocket gui code
nixnax	226:4898247048c7	846	#define DUMP_WEBSOCKET_CHALLENGE_NO
nixnax	226:4898247048c7	847	#ifdef DUMP_WEBSOCKET_CHALLENGE_YES
nixnax	226:4898247048c7	848	debugPrintf("Challenge is %s\n", challenge); // the string we hash for the challenge
nixnax	227:f87156f9ef11	849	#endif
nixnax	142:54d1543e23e5	850	char shaOutput [20]; // sha1 output
nixnax	184:4133f557d4d4	851	sha1( shaOutput, challenge, strlen(challenge)); // hash the challenge
nixnax	142:54d1543e23e5	852	char encOut[50];
nixnax	184:4133f557d4d4	853	enc64( shaOutput, encOut, 20); // base-64 encode
nixnax	142:54d1543e23e5	854	char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax	142:54d1543e23e5	855	char * version = challenge;
nixnax	184:4133f557d4d4	856	strncpy(version, versionstring,70); // copy their version string
nixnax	142:54d1543e23e5	857	*strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax	240:d7a01533397d	858	memset(dataStart,0,500); // blank out old data before sending the websocket response header
nixnax	142:54d1543e23e5	859	n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax	142:54d1543e23e5	860	n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax	142:54d1543e23e5	861	n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax	142:54d1543e23e5	862	n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax	142:54d1543e23e5	863	n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax	142:54d1543e23e5	864	n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax	142:54d1543e23e5	865	n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax	142:54d1543e23e5	866	}
nixnax	142:54d1543e23e5	867	return n; // this response should satisfy a web browser's websocket protocol request
nixnax	142:54d1543e23e5	868	}
nixnax	142:54d1543e23e5	869
nixnax	142:54d1543e23e5	870	#define TCP_FLAG_ACK (1<<4)
nixnax	142:54d1543e23e5	871	#define TCP_FLAG_SYN (1<<1)
nixnax	142:54d1543e23e5	872	#define TCP_FLAG_PSH (1<<3)
nixnax	142:54d1543e23e5	873	#define TCP_FLAG_RST (1<<2)
nixnax	142:54d1543e23e5	874	#define TCP_FLAG_FIN (1<<0)
nixnax	142:54d1543e23e5	875
nixnax	142:54d1543e23e5	876	/// respond to an HTTP request
nixnax	185:4cd8f91e9d49	877	int httpResponse(char * dataStart, int * flags)
nixnax	142:54d1543e23e5	878	{
nixnax	142:54d1543e23e5	879	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	880	n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax	160:bd701ad564cb	881	if (n>0) return n; // if n>0 we already have a response, so return
nixnax	142:54d1543e23e5	882
nixnax	142:54d1543e23e5	883	int nHeader; // byte size of HTTP header
nixnax	142:54d1543e23e5	884	int contentLengthStart; // index where HTML starts
nixnax	142:54d1543e23e5	885	int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax	185:4cd8f91e9d49	886	*flags = TCP_FLAG_ACK \| TCP_FLAG_FIN; // the default case is that we close the connection
nixnax	142:54d1543e23e5	887
nixnax	142:54d1543e23e5	888	httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax	142:54d1543e23e5	889	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	890	httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	891	httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	892	// for example, you could try this using netcat (nc): echo "GET /x" \| nc 172.10.10.2
nixnax	210:a2a651249a9a	893	if( (httpGetRoot==0) \|\| (httpGetx==0) \|\| (httpGet5 == 'w') ) {
nixnax	229:a81c37376187	894	n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed PPP-Blinky\r\n"); // 200 OK header
nixnax	142:54d1543e23e5	895	} else {
nixnax	229:a81c37376187	896	n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed PPP-Blinky\r\n"); // 404 header
nixnax	142:54d1543e23e5	897	}
nixnax	142:54d1543e23e5	898	n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax	142:54d1543e23e5	899	contentLengthStart = n; // remember where Content-Length is in buffer
nixnax	142:54d1543e23e5	900	n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax	142:54d1543e23e5	901	n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax	217:86498f9ab967	902	#define SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	903	#ifdef SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	904	// 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	905	n=n+sprintf(n+dataStart,"Maxbuflevel: %d\r\n", ppp.rx.maxbuflevel);
nixnax	210:a2a651249a9a	906	#endif
nixnax	241:dece92cb7296	907	#define SHOWPINGCOUNT_NO
nixnax	240:d7a01533397d	908	#ifdef SHOWPINGCOUNT_YES
nixnax	241:dece92cb7296	909	// 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	910	n=n+sprintf(n+dataStart,"PingCount: %d\r\n", ppp.pingCount);
nixnax	240:d7a01533397d	911	#endif
nixnax	142:54d1543e23e5	912	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	913	nHeader=n; // size of HTTP header
nixnax	210:a2a651249a9a	914
nixnax	142:54d1543e23e5	915	if( httpGetRoot == 0 ) {
nixnax	142:54d1543e23e5	916	// this is where we insert our web page into the buffer
nixnax	142:54d1543e23e5	917	memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax	142:54d1543e23e5	918	n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax	241:dece92cb7296	919	// naximum length of pingCount (maximum number of digits of an unsigned 32-bit int)
nixnax	241:dece92cb7296	920	#define PINGCOUNTMAXLEN (10)
nixnax	241:dece92cb7296	921	char pingCountString[PINGCOUNTMAXLEN+1]; // space for the ten digits and a string terminator 0
nixnax	241:dece92cb7296	922	snprintf(pingCountString,PINGCOUNTMAXLEN+1,"%*d",PINGCOUNTMAXLEN,ppp.pingCount); // print number of ICMP pings right justified in 10 spaces
nixnax	241:dece92cb7296	923	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	924	if ( pingCountStart != NULL )
nixnax	241:dece92cb7296	925	memcpy(pingCountStart, pingCountString, PINGCOUNTMAXLEN); // copy ping count over the ten zeros in the page
nixnax	210:a2a651249a9a	926	} else if ( httpGet5 == 'w' ) { // "w" is a special page for websocket demo
nixnax	142:54d1543e23e5	927	memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax	142:54d1543e23e5	928	n = n + sizeof(webSocketPage)-1; // one less than size
nixnax	185:4cd8f91e9d49	929	*flags = TCP_FLAG_ACK \| TCP_FLAG_PSH; // for a websocket page we do NOT close the connection
nixnax	142:54d1543e23e5	930	} else {
nixnax	142:54d1543e23e5	931	if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax	142:54d1543e23e5	932	#define W3C_COMPLIANT_RESPONSE_NO
nixnax	142:54d1543e23e5	933	// change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax	142:54d1543e23e5	934	#ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax	142:54d1543e23e5	935	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax	146:a45f49a2b29c	936	n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax	142:54d1543e23e5	937	#else
nixnax	142:54d1543e23e5	938	if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax	167:ff8a2d8beeb1	939	n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax	142:54d1543e23e5	940	}
nixnax	142:54d1543e23e5	941	// /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax	146:a45f49a2b29c	942	n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax	142:54d1543e23e5	943	#endif
nixnax	142:54d1543e23e5	944	} else {
nixnax	142:54d1543e23e5	945	// all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax	142:54d1543e23e5	946	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax	142:54d1543e23e5	947	n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax	142:54d1543e23e5	948	}
nixnax	142:54d1543e23e5	949	}
nixnax	142:54d1543e23e5	950	#define CONTENTLENGTHSIZE 5
nixnax	142:54d1543e23e5	951	char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax	142:54d1543e23e5	952	snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax	142:54d1543e23e5	953	memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax	142:54d1543e23e5	954	return n; // total byte size of our response
nixnax	142:54d1543e23e5	955	}
nixnax	142:54d1543e23e5	956
nixnax	160:bd701ad564cb	957	/// Handle TCP data that is not an HTTP GET.
nixnax	160:bd701ad564cb	958	/// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax	160:bd701ad564cb	959	/// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax	142:54d1543e23e5	960	int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax	142:54d1543e23e5	961	{
nixnax	142:54d1543e23e5	962	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	963	if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax	160:bd701ad564cb	964	char mask [4];
nixnax	160:bd701ad564cb	965	memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax	160:bd701ad564cb	966	int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax	160:bd701ad564cb	967	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	968	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	969	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	970	memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax	160:bd701ad564cb	971	n = len; // our response size remains exactly the same length as what we received
nixnax	142:54d1543e23e5	972	} else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax	142:54d1543e23e5	973	n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax	142:54d1543e23e5	974	dataStart[1]=0; // we don't have mask bytes on
nixnax	160:bd701ad564cb	975	} else {
nixnax	184:4133f557d4d4	976	if ( len > 1 ) { // we assume a length of 1 is a keep-alive or push packet
nixnax	221:1d7c32d8256b	977	if (v1) debugPuts("TCP data received\n"); // all other tcp push packets
nixnax	184:4133f557d4d4	978	}
nixnax	163:d1b4328e9f08	979	}
nixnax	142:54d1543e23e5	980	return n; // total byte size of our response
nixnax	142:54d1543e23e5	981	}
nixnax	142:54d1543e23e5	982
nixnax	173:6774a0c851c4	983	/// dump the TCP data to the debug serial port
nixnax	173:6774a0c851c4	984	void dumpDataTCP(int outGoing)
nixnax	173:6774a0c851c4	985	{
nixnax	173:6774a0c851c4	986	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	173:6774a0c851c4	987	if (v2) {
nixnax	173:6774a0c851c4	988	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	173:6774a0c851c4	989	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	990	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax	173:6774a0c851c4	991	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	173:6774a0c851c4	992	ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
nixnax	173:6774a0c851c4	993	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	173:6774a0c851c4	994	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	230:ee097c486e45	995	char pbuf[100]; // local print buffer
nixnax	173:6774a0c851c4	996	int n=0;
nixnax	210:a2a651249a9a	997
nixnax	173:6774a0c851c4	998	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	210:a2a651249a9a	999
nixnax	173:6774a0c851c4	1000	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	1001	if (n>95) debugPuts("n>pbuf overflow in dumpDataTCP()\n");
nixnax	210:a2a651249a9a	1002
nixnax	221:1d7c32d8256b	1003	debugPuts( pbuf );
nixnax	173:6774a0c851c4	1004	if (tcpDataSize > 0) {
nixnax	173:6774a0c851c4	1005	ppp.tcpData[tcpDataSize]=0; // insert a null after the data so debug printf stops printing after the data
nixnax	221:1d7c32d8256b	1006	debugPuts( ppp.tcpData ); // print the tcp payload data
nixnax	221:1d7c32d8256b	1007	debugPuts("\n");
nixnax	173:6774a0c851c4	1008	}
nixnax	221:1d7c32d8256b	1009	debugPuts( "\x1b[30m" ); // VT100 color code, print black
nixnax	173:6774a0c851c4	1010	}
nixnax	173:6774a0c851c4	1011	#endif
nixnax	173:6774a0c851c4	1012	}
nixnax	173:6774a0c851c4	1013
nixnax	142:54d1543e23e5	1014	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1015	/// 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	1016	void tcpHandler()
nixnax	142:54d1543e23e5	1017	{
nixnax	154:18b2bd92f557	1018	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	154:18b2bd92f557	1019	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	1020	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate TCP header start
nixnax	154:18b2bd92f557	1021	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	154:18b2bd92f557	1022	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	227:f87156f9ef11	1023	char * tcpDataIn = ppp.tcpStart + headerSizeTcp; // start of TCP data after TCP header
nixnax	154:18b2bd92f557	1024	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	154:18b2bd92f557	1025
nixnax	227:f87156f9ef11	1026	unsigned int seq_in = __REV(ppp.tcp->seqTcpR); // incoming sequence number
nixnax	227:f87156f9ef11	1027	unsigned int ack_in = __REV(ppp.tcp->ackTcpR); // incoming acknowledge number
nixnax	227:f87156f9ef11	1028	unsigned int ack_out = seq_in + tcpDataSize; // calculate the acknowledge based on size of received packet
nixnax	227:f87156f9ef11	1029	unsigned int seq_out = ack_in; // adopt their version of our sequence number as our sequence number
nixnax	142:54d1543e23e5	1030
nixnax	142:54d1543e23e5	1031	// first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax	173:6774a0c851c4	1032	headerSizeIp=20;
nixnax	173:6774a0c851c4	1033	ppp.ip->headerLength = headerSizeIp/4; // ip header is 20 bytes long
nixnax	173:6774a0c851c4	1034	ppp.ip->lengthR = __REV(40); // 20 ip header + 20 tcp header
nixnax	227:f87156f9ef11	1035	headerSizeTcp = 20; // shorten outgoing TCP header size to 20 bytes (no data)
nixnax	173:6774a0c851c4	1036	ppp.tcpStart = ppp.ipStart + headerSizeIp; // recalc TCP header start
nixnax	154:18b2bd92f557	1037	ppp.tcp->offset = (headerSizeTcp/4);
nixnax	173:6774a0c851c4	1038	char * tcpDataOut = ppp.tcpStart + headerSizeTcp; // start of outgoing data
nixnax	142:54d1543e23e5	1039
nixnax	142:54d1543e23e5	1040	int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax	142:54d1543e23e5	1041	int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax	160:bd701ad564cb	1042
nixnax	185:4cd8f91e9d49	1043	ppp.tcp->windowR = __REV16( 1200 ); // set tcp window size to 1200 bytes
nixnax	142:54d1543e23e5	1044
nixnax	142:54d1543e23e5	1045	// A sparse TCP flag interpreter that implements stateless TCP connections
nixnax	142:54d1543e23e5	1046
nixnax	156:163c23249731	1047	switch ( ppp.tcp->flag.All ) {
nixnax	142:54d1543e23e5	1048	case TCP_FLAG_SYN:
nixnax	142:54d1543e23e5	1049	flagsOut = TCP_FLAG_SYN \| TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax	142:54d1543e23e5	1050	seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax	142:54d1543e23e5	1051	ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1052	break;
nixnax	184:4133f557d4d4	1053	case TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1054	case TCP_FLAG_ACK \| TCP_FLAG_PSH:
nixnax	184:4133f557d4d4	1055	if ( (ppp.tcp->flag.All == TCP_FLAG_ACK) && (tcpDataSize == 0)) return; // handle zero-size ack messages by ignoring them
nixnax	142:54d1543e23e5	1056	if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax	237:796851817c26	1057	led1Toggle(); // toggle the LED one more time so we can visualize the HTTP GET
nixnax	179:ba2b2ddd0da5	1058	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // we have data, set the PSH flag
nixnax	185:4cd8f91e9d49	1059	dataLen = httpResponse(tcpDataOut, &flagsOut); // send an http response
nixnax	142:54d1543e23e5	1060	} else {
nixnax	158:841592aed956	1061	dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax	179:ba2b2ddd0da5	1062	if (dataLen > 0) flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // if we have any data set the PSH flag
nixnax	142:54d1543e23e5	1063	}
nixnax	142:54d1543e23e5	1064	break;
nixnax	142:54d1543e23e5	1065	case TCP_FLAG_FIN:
nixnax	142:54d1543e23e5	1066	case TCP_FLAG_FIN \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1067	case TCP_FLAG_FIN \| TCP_FLAG_PSH \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1068	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax	142:54d1543e23e5	1069	ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1070	break;
nixnax	142:54d1543e23e5	1071	default:
nixnax	179:ba2b2ddd0da5	1072	return; // ignore all other packets
nixnax	142:54d1543e23e5	1073	} // switch
nixnax	142:54d1543e23e5	1074
nixnax	142:54d1543e23e5	1075	// The TCP flag handling is now done
nixnax	142:54d1543e23e5	1076	// first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax	147:0f40005cbc5f	1077	swapIpAddresses(); // swap IP source and destination addresses
nixnax	149:969d98f6fb88	1078	swapIpPorts(); // swap IP source and destination ports
nixnax	142:54d1543e23e5	1079
nixnax	158:841592aed956	1080	ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	158:841592aed956	1081	ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	160:bd701ad564cb	1082
nixnax	156:163c23249731	1083	ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax	142:54d1543e23e5	1084
nixnax	159:4d1bf96a59cd	1085	// recalculate all the header sizes
nixnax	154:18b2bd92f557	1086	tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax	154:18b2bd92f557	1087	int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax	159:4d1bf96a59cd	1088	ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax	142:54d1543e23e5	1089	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	1090
nixnax	142:54d1543e23e5	1091	// the header is all set up, now do the IP and TCP checksums
nixnax	146:a45f49a2b29c	1092	IpHeaderCheckSum(); // calculate new IP header checksum
nixnax	170:3d3b2126181c	1093	checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax	159:4d1bf96a59cd	1094	ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	161:d59f778bc8ab	1095	unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax	159:4d1bf96a59cd	1096	ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	160:bd701ad564cb	1097
nixnax	170:3d3b2126181c	1098	dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax	170:3d3b2126181c	1099	dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax	173:6774a0c851c4	1100	dumpDataTCP(1); // dump outgoing TCP data before sending the frame
nixnax	226:4898247048c7	1101	#define WAIT_BEFORE_IP_SEND_NO
nixnax	226:4898247048c7	1102	#ifdef WAIT_BEFORE_IP_SEND_YES
nixnax	226:4898247048c7	1103	wait_ms(45); // 45 ms delay before sending frame
nixnax	226:4898247048c7	1104	#endif
nixnax	144:01d98cf7738e	1105	sendPppFrame(); // All preparation complete - send the TCP response
nixnax	226:4898247048c7	1106	#define DUMP_TRANSMITTED_PPP_NO
nixnax	226:4898247048c7	1107	#ifdef DUMP_TRANSMITTED_PPP_YES
nixnax	226:4898247048c7	1108	dumpPPPFrame(); // dump every transmitted ppp frame to debug port
nixnax	226:4898247048c7	1109	#endif
nixnax	142:54d1543e23e5	1110	memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax	142:54d1543e23e5	1111	}
nixnax	142:54d1543e23e5	1112
nixnax	142:54d1543e23e5	1113	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1114	void TCPpacket()
nixnax	142:54d1543e23e5	1115	{
nixnax	173:6774a0c851c4	1116	dumpHeaderIP(0); // dump incoming packet IP header
nixnax	173:6774a0c851c4	1117	dumpHeaderTCP(0); // dump incoming packet TCP header
nixnax	173:6774a0c851c4	1118	dumpDataTCP(0); // dump incoming packet data
nixnax	142:54d1543e23e5	1119	tcpHandler();
nixnax	142:54d1543e23e5	1120	}
nixnax	142:54d1543e23e5	1121
nixnax	142:54d1543e23e5	1122	/// handle the remaining IP protocols by ignoring them
nixnax	142:54d1543e23e5	1123	void otherProtocol()
nixnax	142:54d1543e23e5	1124	{
nixnax	230:ee097c486e45	1125	debugPuts("Other IP protocol");
nixnax	142:54d1543e23e5	1126	}
nixnax	142:54d1543e23e5	1127
nixnax	142:54d1543e23e5	1128	/// process an incoming IP packet
nixnax	142:54d1543e23e5	1129	void IPframe()
nixnax	142:54d1543e23e5	1130	{
nixnax	167:ff8a2d8beeb1	1131	int protocol = ppp.ip->protocol;
nixnax	142:54d1543e23e5	1132	switch (protocol) {
nixnax	142:54d1543e23e5	1133	case 1:
nixnax	142:54d1543e23e5	1134	ICMPpacket();
nixnax	142:54d1543e23e5	1135	break;
nixnax	142:54d1543e23e5	1136	case 2:
nixnax	142:54d1543e23e5	1137	IGMPpacket();
nixnax	142:54d1543e23e5	1138	break;
nixnax	142:54d1543e23e5	1139	case 17:
nixnax	142:54d1543e23e5	1140	UDPpacket();
nixnax	142:54d1543e23e5	1141	break;
nixnax	142:54d1543e23e5	1142	case 6:
nixnax	142:54d1543e23e5	1143	TCPpacket();
nixnax	142:54d1543e23e5	1144	break;
nixnax	142:54d1543e23e5	1145	default:
nixnax	142:54d1543e23e5	1146	otherProtocol();
nixnax	142:54d1543e23e5	1147	}
nixnax	142:54d1543e23e5	1148	}
nixnax	142:54d1543e23e5	1149
nixnax	227:f87156f9ef11	1150	/// process LCP packets
nixnax	142:54d1543e23e5	1151	void LCPframe()
nixnax	142:54d1543e23e5	1152	{
nixnax	175:b4e6f8a6fe00	1153	int code = ppp.lcp->code;
nixnax	142:54d1543e23e5	1154	switch (code) {
nixnax	227:f87156f9ef11	1155	case 1: // LCP configuration request
nixnax	231:6bd4523833a2	1156	debugPuts("LCP Config");
nixnax	227:f87156f9ef11	1157	if ( __REV16( ppp.lcp->lengthR ) == 4 ) {
nixnax	230:ee097c486e45	1158	debugPuts("LCP Ack\n");
nixnax	227:f87156f9ef11	1159	ppp.lcp->code=2; // acknowledge zero configuration request
nixnax	227:f87156f9ef11	1160	sendPppFrame();
nixnax	227:f87156f9ef11	1161	ppp.lcp->code=1; // request no options
nixnax	227:f87156f9ef11	1162	sendPppFrame();
nixnax	227:f87156f9ef11	1163	} else {
nixnax	230:ee097c486e45	1164	debugPuts("LCP request reject\n");
nixnax	227:f87156f9ef11	1165	ppp.lcp->code=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax	227:f87156f9ef11	1166	sendPppFrame();
nixnax	227:f87156f9ef11	1167	}
nixnax	227:f87156f9ef11	1168	break;
nixnax	227:f87156f9ef11	1169	case 2: // LCP configuration acknowledge
nixnax	230:ee097c486e45	1170	debugPuts("LCP Ack\n"); // don't do anything, i.e. ignore
nixnax	227:f87156f9ef11	1171	break;
nixnax	227:f87156f9ef11	1172	case 5: // LCP end
nixnax	227:f87156f9ef11	1173	ppp.lcp->code=6; // acknowledge
nixnax	227:f87156f9ef11	1174	sendPppFrame(); // acknowledge
nixnax	227:f87156f9ef11	1175	ppp.online=0; // start hunting for connect string again
nixnax	227:f87156f9ef11	1176	pppInitStruct(); // flush the receive buffer
nixnax	230:ee097c486e45	1177	debugPuts("LCP End (Disconnect from host)\n");
nixnax	142:54d1543e23e5	1178	break; // end connection
nixnax	142:54d1543e23e5	1179	default:
nixnax	231:6bd4523833a2	1180	debugPuts("LCP Other\n");
nixnax	142:54d1543e23e5	1181	}
nixnax	142:54d1543e23e5	1182	}
nixnax	142:54d1543e23e5	1183
nixnax	142:54d1543e23e5	1184	/// discard packets that are not IP, IPCP, or LCP
nixnax	142:54d1543e23e5	1185	void discardedFrame()
nixnax	142:54d1543e23e5	1186	{
nixnax	142:54d1543e23e5	1187	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	1188	}
nixnax	142:54d1543e23e5	1189
nixnax	142:54d1543e23e5	1190	/// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax	142:54d1543e23e5	1191	void determinePacketType()
nixnax	142:54d1543e23e5	1192	{
nixnax	167:ff8a2d8beeb1	1193	if ( ppp.ppp->address != 0xff ) {
nixnax	231:6bd4523833a2	1194	debugPuts("Unexpected: PPP address != ff\n");
nixnax	142:54d1543e23e5	1195	return;
nixnax	142:54d1543e23e5	1196	}
nixnax	167:ff8a2d8beeb1	1197	if ( ppp.ppp->control != 3 ) {
nixnax	231:6bd4523833a2	1198	debugPuts("Unexpected: PPP control != 3\n");
nixnax	142:54d1543e23e5	1199	return;
nixnax	142:54d1543e23e5	1200	}
nixnax	167:ff8a2d8beeb1	1201	unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax	167:ff8a2d8beeb1	1202	switch ( protocol ) {
nixnax	167:ff8a2d8beeb1	1203	case 0xc021:
nixnax	142:54d1543e23e5	1204	LCPframe();
nixnax	142:54d1543e23e5	1205	break; // link control
nixnax	167:ff8a2d8beeb1	1206	case 0x8021:
nixnax	142:54d1543e23e5	1207	IPCPframe();
nixnax	142:54d1543e23e5	1208	break; // IP control
nixnax	167:ff8a2d8beeb1	1209	case 0x0021:
nixnax	142:54d1543e23e5	1210	IPframe();
nixnax	142:54d1543e23e5	1211	break; // IP itself
nixnax	142:54d1543e23e5	1212	default:
nixnax	142:54d1543e23e5	1213	discardedFrame();
nixnax	142:54d1543e23e5	1214	}
nixnax	142:54d1543e23e5	1215	}
nixnax	142:54d1543e23e5	1216
nixnax	146:a45f49a2b29c	1217	/// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax	146:a45f49a2b29c	1218	void sniff()
nixnax	146:a45f49a2b29c	1219	{
nixnax	221:1d7c32d8256b	1220	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	1221	}
nixnax	146:a45f49a2b29c	1222
nixnax	142:54d1543e23e5	1223	/// scan the PPP serial input stream for frame start markers
nixnax	143:c5019f856a56	1224	void waitForPppFrame()
nixnax	142:54d1543e23e5	1225	{
nixnax	142:54d1543e23e5	1226	while(1) {
nixnax	142:54d1543e23e5	1227	if ( ppp.rx.head != ppp.rx.tail ) {
nixnax	142:54d1543e23e5	1228	int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax	142:54d1543e23e5	1229	int rx = pc_getBuf(); // get the character
nixnax	238:f39289ed5a2e	1230	if (rx==0x7e) { // check for frame start/end character 0x7e
nixnax	142:54d1543e23e5	1231	if (ppp.firstFrame) { // is this the start of the first frame start
nixnax	142:54d1543e23e5	1232	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1233	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax	181:bcfe7fe2142d	1234	ppp.firstFrame=0; // clear first frame flag
nixnax	142:54d1543e23e5	1235	} else {
nixnax	142:54d1543e23e5	1236	ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax	142:54d1543e23e5	1237	processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax	142:54d1543e23e5	1238	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1239	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax	142:54d1543e23e5	1240	break;
nixnax	142:54d1543e23e5	1241	}
nixnax	142:54d1543e23e5	1242	}
nixnax	142:54d1543e23e5	1243	}
nixnax	210:a2a651249a9a	1244	// change below to YES to enable the serial to UDP demo
nixnax	210:a2a651249a9a	1245	#define SERIAL_TO_UDP_NO
nixnax	210:a2a651249a9a	1246	#ifdef SERIAL_TO_UDP_YES
nixnax	210:a2a651249a9a	1247	sendUdpData(); // demo that sends characters received on the DEBUG serial port via UDP to another host
nixnax	210:a2a651249a9a	1248	#endif
nixnax	142:54d1543e23e5	1249	}
nixnax	142:54d1543e23e5	1250	}
nixnax	142:54d1543e23e5	1251
nixnax	209:aa514cd631ee	1252	/// 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	1253	// 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	1254	void waitForPcConnectString()
nixnax	142:54d1543e23e5	1255	{
nixnax	142:54d1543e23e5	1256	while(ppp.online == 0) {
nixnax	142:54d1543e23e5	1257	// search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax	142:54d1543e23e5	1258	char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax	142:54d1543e23e5	1259	if (found1 != NULL) {
nixnax	230:ee097c486e45	1260	if (v0) debugPuts("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax	208:73086736610a	1261	// respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax	142:54d1543e23e5	1262	pc.puts("CLIENTSERVER");
nixnax	142:54d1543e23e5	1263	ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax	142:54d1543e23e5	1264	}
nixnax	142:54d1543e23e5	1265	}
nixnax	142:54d1543e23e5	1266	}
nixnax	142:54d1543e23e5	1267
nixnax	144:01d98cf7738e	1268	/// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax	144:01d98cf7738e	1269	void initializePpp()
nixnax	142:54d1543e23e5	1270	{
nixnax	210:a2a651249a9a	1271	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	144:01d98cf7738e	1272	debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax	230:ee097c486e45	1273	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	1274	wait_ms(200); // a brief wait so a human can see the reset event
nixnax	230:ee097c486e45	1275	debugPuts("mbed PPP-Blinky HTTP & WebSocket server ready :)\n");
nixnax	210:a2a651249a9a	1276	#endif
nixnax	179:ba2b2ddd0da5	1277	pppInitStruct(); // initialize all the variables/properties/buffers
nixnax	179:ba2b2ddd0da5	1278	pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
nixnax	179:ba2b2ddd0da5	1279	pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
nixnax	143:c5019f856a56	1280	}

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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.