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@248:5aca1c98fc24, 2018-12-25 (annotated)

Committer:: nixnax
Date:: Tue Dec 25 10:43:41 2018 +0000
Revision:: 248:5aca1c98fc24
Parent:: 247:7b0a8e6fbb86
Child:: 249:9ff0e20325f7

Use Data URI for fake favicon image

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

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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.