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@255:14e83e1e2b40, 2019-03-02 (annotated)

Committer:: nixnax
Date:: Sat Mar 02 19:18:40 2019 +0000
Revision:: 255:14e83e1e2b40
Parent:: 254:7345c9a6f4c2
Child:: 256:16543c8dd55c

new mbed library revision 172

Who changed what in which revision?

User	Revision	Line number	New contents of line
nixnax	182:f039ec218c9f	1	// PPP-Blinky - "The Most Basic Internet Thing"
nixnax	142:54d1543e23e5	2	// A Tiny HTTP Webserver Using Windows XP/7/8/10/Linux Dial-Up Networking Over A Serial Port.
nixnax	142:54d1543e23e5	3	// Receives UDP packets and responds to ping (ICMP Echo requests)
nixnax	142:54d1543e23e5	4	// WebSocket Service - see https://en.wikipedia.org/wiki/WebSocket
nixnax	142:54d1543e23e5	5
nixnax	142:54d1543e23e5	6	// Copyright 2016/2017 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax	142:54d1543e23e5	7
nixnax	142:54d1543e23e5	8	// Notes and Instructions
nixnax	142:54d1543e23e5	9	// http://bit.ly/PPP-Blinky-Instructions
nixnax	142:54d1543e23e5	10	// http://bit.ly/win-rasdial-config
nixnax	142:54d1543e23e5	11
nixnax	201:9fcf92e9f427	12	// Important - ensure that you are using the latest mbed firmware for your specific mbed target board
nixnax	201:9fcf92e9f427	13
nixnax	142:54d1543e23e5	14	// Handy reading material
nixnax	142:54d1543e23e5	15	// https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax	142:54d1543e23e5	16	// https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax	142:54d1543e23e5	17	// http://atari.kensclassics.org/wcomlog.htm
nixnax	249:9ff0e20325f7	18	// https://en.wikipedia.org/wiki/Favicon (see also html5 <link> tag)
nixnax	142:54d1543e23e5	19
nixnax	142:54d1543e23e5	20	// Handy tools
nixnax	142:54d1543e23e5	21	// https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax	142:54d1543e23e5	22	// https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax	142:54d1543e23e5	23	// http://pingtester.net/ - nice tool for high rate ping testing
nixnax	142:54d1543e23e5	24	// http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE), then custom relected-in=1, reflected-out=1
nixnax	142:54d1543e23e5	25	// https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax	142:54d1543e23e5	26	// https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax	142:54d1543e23e5	27	// Windows Powershell invoke-webrequest command - use it to stress test the webserver like this: while (1){ invoke-webrequest -uri 172.10.10.1/x }
nixnax	142:54d1543e23e5	28
nixnax	142:54d1543e23e5	29	// Connecting PPP-Blinky to Linux
nixnax	142:54d1543e23e5	30	// PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax	142:54d1543e23e5	31	// pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax	142:54d1543e23e5	32	// in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax	142:54d1543e23e5	33	// See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax	142:54d1543e23e5	34
nixnax	142:54d1543e23e5	35	// Special pages when PPP-Blinky is running
nixnax	142:54d1543e23e5	36	// 172.10.10.2 root page
nixnax	182:f039ec218c9f	37	// 172.10.10.2/x returns the number of ppp frames sent - this is handy for testing
nixnax	182:f039ec218c9f	38	// 172.10.10.2/xb also returns number of ppp frames sent, but issues a fast refresh meta command. This allows you to use your browser to benchmark page load speed
nixnax	142:54d1543e23e5	39	// 172.10.10.2/ws a simple WebSocket demo
nixnax	182:f039ec218c9f	40	// http://jsfiddle.net/d26cyuh2/ more complete WebSocket demo in JSFiddle, showing cross-domain access
nixnax	207:28cd834b785d	41
nixnax	142:54d1543e23e5	42	// Ok, enough talking, time to check out some code!!
nixnax	142:54d1543e23e5	43
nixnax	142:54d1543e23e5	44	#include "ppp-blinky.h"
nixnax	142:54d1543e23e5	45
nixnax	142:54d1543e23e5	46	// The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax	146:a45f49a2b29c	47	// Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor the debug output.
nixnax	142:54d1543e23e5	48	// Using the second serial port will slow down packet response time
nixnax	142:54d1543e23e5	49	// Note - the LPC11U24 does NOT have a second serial port
nixnax	146:a45f49a2b29c	50
nixnax	183:6d3ba874b267	51	#define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax	142:54d1543e23e5	52
nixnax	142:54d1543e23e5	53	// here we define the OPTIONAL, second debug serial port for various mbed target boards
nixnax	142:54d1543e23e5	54	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	142:54d1543e23e5	55	#if defined(TARGET_LPC1768)
nixnax	179:ba2b2ddd0da5	56	RawSerial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	57	#elif defined(TARGET_NUCLEO_F446RE) \|\| defined(TARGET_NUCLEO_L152RE) \|\| defined(TARGET_NUCLEO_L053R8) \|\| defined(TARGET_NUCLEO_L476RG) \|\| defined(TARGET_NUCLEO_F401RE)
nixnax	179:ba2b2ddd0da5	58	RawSerial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	196:8791e241be80	59	#elif defined(TARGET_NUCLEO_L432KC)
nixnax	196:8791e241be80	60	RawSerial xx(PA_9, PA_10); // Second serial port on NUCLEO-L432KC - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	61	#elif defined(TARGET_LPC11U24)
nixnax	142:54d1543e23e5	62	#error The LPC11U24 does not have a second serial port to use for debugging - change SERIAL_PORT_MONITOR_YES back to SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	63	#elif defined (TARGET_KL46Z) \|\| (TARGET_KL25Z)
nixnax	179:ba2b2ddd0da5	64	RawSerial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax	193:48072570f41d	65	#elif defined(TARGET_KW41Z)
nixnax	194:5b23ebfb3626	66	RawSerial xx(PTC3, PTC2); // Second serial port on FRDM-KW41Z board
nixnax	142:54d1543e23e5	67	#elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax	142:54d1543e23e5	68	// change the next line to YOUR target board's second serial port pin definition if it's not present - and if it works, please send it to me - thanks!!!
nixnax	226:4898247048c7	69	RawSerial xx(p9, p10); // change this to YOUR board's second serial port pin definition - and please send it to me if it works!!!
nixnax	142:54d1543e23e5	70	#else
nixnax	142:54d1543e23e5	71	#error Add your target board's second serial port here if you want to use debugging - or simply change SERIAL_PORT_MONITOR_YES to SERIAL_PORT_MONITOR_NO
nixnax	142:54d1543e23e5	72	#endif
nixnax	179:ba2b2ddd0da5	73	#define debugPrintf(x...) xx.printf (x) /* if we have a serial port we can print debug messages */
nixnax	142:54d1543e23e5	74	#define debugPutc(x...) xx.putc(x)
nixnax	221:1d7c32d8256b	75	#define debugPuts(x...) xx.puts(x)
nixnax	142:54d1543e23e5	76	#define debugBaudRate(x...) xx.baud(x)
nixnax	142:54d1543e23e5	77	#else
nixnax	142:54d1543e23e5	78	// if we don't have a debug port the debug print functions do nothing
nixnax	142:54d1543e23e5	79	#define debugPrintf(x...) {}
nixnax	142:54d1543e23e5	80	#define debugPutc(x...) {}
nixnax	221:1d7c32d8256b	81	#define debugPuts(x...) {}
nixnax	142:54d1543e23e5	82	#define debugBaudRate(x...) {}
nixnax	142:54d1543e23e5	83	#endif
nixnax	142:54d1543e23e5	84
nixnax	142:54d1543e23e5	85	// verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax	182:f039ec218c9f	86	#define v0 1
nixnax	142:54d1543e23e5	87	#define v1 0
nixnax	142:54d1543e23e5	88	#define v2 0
nixnax	182:f039ec218c9f	89	#define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax	182:f039ec218c9f	90	#define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax	226:4898247048c7	91	#define DUMP_RECEIVED_PPP_FRAMES_NO /* YES to dump received PPP frames */
nixnax	142:54d1543e23e5	92
nixnax	226:4898247048c7	93	// below is the webpage we serve when we get an HTTP request to root (/)
nixnax	226:4898247048c7	94	// keep size under ~1400 bytes to fit into a single PPP packet
nixnax	249:9ff0e20325f7	95	// the <link rel="icon" ...> tag stops browsers from asking for file favicon.ico
nixnax	142:54d1543e23e5	96
nixnax	142:54d1543e23e5	97	const static char rootWebPage[] = "\
nixnax	142:54d1543e23e5	98	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	99	<html>\
nixnax	248:5aca1c98fc24	100	<!--Comment-->\
nixnax	142:54d1543e23e5	101	<head>\
nixnax	146:a45f49a2b29c	102	<title>mbed PPP-Blinky</title>\r\n\
nixnax	248:5aca1c98fc24	103	<link rel=\"icon\" href=\"data:image/gif;base64,R0lGODlhAQABAIABAP8AAAAAACwAAAAAAQABAAACAkQBADs=\">\
nixnax	226:4898247048c7	104	<style>\
nixnax	241:dece92cb7296	105	body {font-family:sans-serif; font-size:140%; text-align:center; color:#807070;}\
nixnax	248:5aca1c98fc24	106	</style>\r\n\
nixnax	142:54d1543e23e5	107	</head>\
nixnax	226:4898247048c7	108	<body>\
nixnax	142:54d1543e23e5	109	<h1>mbed PPP-Blinky Up and Running</h1>\
nixnax	142:54d1543e23e5	110	<h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax	210:a2a651249a9a	111	<h1><a href=\"/w\">WebSocket Test</a></h1>\
nixnax	245:544cea761769	112	<h1><a href=\"/x?Parameter1=Example\">Benchmark 1</a></h1>\
nixnax	142:54d1543e23e5	113	<h1><a href=\"/xb\">Benchmark 2</a></h1>\
nixnax	241:dece92cb7296	114	<h1><a href=\"http://jsfiddle.net/d26cyuh2/112/embedded/result\">JSFiddle Demo</a></h1>\
nixnax	252:b3c8c5699153	115	<h1>TCP, LCP & Ping Count: 0000000000</h1>\
nixnax	254:7345c9a6f4c2	116	<h1>System Core Clock: 0000000000</h1>\
nixnax	241:dece92cb7296	117	</body>\
nixnax	245:544cea761769	118	</html>\r\n"; // size = 553 bytes + 1 null byte = 554 bytes
nixnax	142:54d1543e23e5	119
nixnax	167:ff8a2d8beeb1	120	// this is a websocket demo html page we serve when GET /ws is requested
nixnax	226:4898247048c7	121	// it contains some javascript to handle the websocket activities
nixnax	249:9ff0e20325f7	122	// the <link rel="icon" ...> tag stops browsers from asking for file favicon.ico
nixnax	142:54d1543e23e5	123	const static char webSocketPage[] = "\
nixnax	142:54d1543e23e5	124	<!DOCTYPE html>\
nixnax	142:54d1543e23e5	125	<html>\
nixnax	142:54d1543e23e5	126	<head>\
nixnax	226:4898247048c7	127	<title>mbed PPP-Blinky WebSocket</title>\
nixnax	248:5aca1c98fc24	128	<link rel=\"icon\" href=\"data:image/gif;base64,R0lGODlhAQABAIABAP8AAAAAACwAAAAAAQABAAACAkQBADs=\">\
nixnax	142:54d1543e23e5	129	<script>\
nixnax	142:54d1543e23e5	130	window.onload=function(){\
nixnax	142:54d1543e23e5	131	var url=\"ws://172.10.10.2\";\
nixnax	142:54d1543e23e5	132	var sts=document.getElementById(\"sts\");\
nixnax	142:54d1543e23e5	133	var btn=document.getElementById(\"btn\");\
nixnax	142:54d1543e23e5	134	var ctr=0;\
nixnax	142:54d1543e23e5	135	function show(text){sts.textContent=text;}\
nixnax	142:54d1543e23e5	136	btn.onclick=function(){\
nixnax	142:54d1543e23e5	137	if(btn.textContent==\"Connect\"){\
nixnax	142:54d1543e23e5	138	x=new WebSocket(url);\
nixnax	142:54d1543e23e5	139	x.onopen=function(){\
nixnax	226:4898247048c7	140	show(\"Connected to PPP-Blinky WebSocket service at: \"+url);\
nixnax	142:54d1543e23e5	141	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	142	};\
nixnax	226:4898247048c7	143	x.onclose=function(){show(\"WebSocket closed\");};\
nixnax	226:4898247048c7	144	x.onmessage=function(msg){show(\"PPP-Blinky WebSocket service responded with: \\\"\"+msg.data+\"\\\"\");};\
nixnax	142:54d1543e23e5	145	} else {\
nixnax	142:54d1543e23e5	146	x.send(ctr);\
nixnax	142:54d1543e23e5	147	ctr=ctr+1;\
nixnax	142:54d1543e23e5	148	btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax	142:54d1543e23e5	149	}\
nixnax	142:54d1543e23e5	150	};\
nixnax	142:54d1543e23e5	151	};\
nixnax	142:54d1543e23e5	152	</script>\
nixnax	226:4898247048c7	153	<style>\
nixnax	241:dece92cb7296	154	body {font-family:sans-serif; font-size:140%; text-align:center; color:#807070;}\
nixnax	241:dece92cb7296	155	button {font-size:140%; background-color:#7eeeee; border-radius:15px; border:none; margin-top:20px; }\
nixnax	226:4898247048c7	156	</style>\
nixnax	226:4898247048c7	157	<body>\
nixnax	226:4898247048c7	158	<h1>mbed PPP-Blinky WebSocket Test</h1>\
nixnax	226:4898247048c7	159	<h1><div id=\"sts\">Idle</div><h1>\
nixnax	226:4898247048c7	160	<button id=\"btn\">Connect</button>\
nixnax	142:54d1543e23e5	161	</body>\
nixnax	226:4898247048c7	162	</html>"; // size = 1037 bytes + 1 null byte = 1038 bytes
nixnax	142:54d1543e23e5	163
nixnax	142:54d1543e23e5	164	// 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	165	// On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax	142:54d1543e23e5	166	// The modem baud rate should be set to 115200 baud
nixnax	142:54d1543e23e5	167	// See instructions at the top.
nixnax	142:54d1543e23e5	168	// 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	169	RawSerial pc (USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax	142:54d1543e23e5	170
nixnax	142:54d1543e23e5	171	DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax	142:54d1543e23e5	172
nixnax	142:54d1543e23e5	173	pppType ppp; // our global - definitely not thread safe
nixnax	142:54d1543e23e5	174
nixnax	142:54d1543e23e5	175	/// Initialize the ppp structure and clear the receive buffer
nixnax	142:54d1543e23e5	176	void pppInitStruct()
nixnax	142:54d1543e23e5	177	{
nixnax	223:917b554cb8a5	178	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	179	ppp.online=0;
nixnax	142:54d1543e23e5	180	ppp.rx.tail=0;
nixnax	142:54d1543e23e5	181	ppp.rx.rtail=0;
nixnax	142:54d1543e23e5	182	ppp.rx.head=0;
nixnax	142:54d1543e23e5	183	ppp.rx.buflevel=0;
nixnax	209:aa514cd631ee	184	ppp.rx.maxbuflevel=0;
nixnax	221:1d7c32d8256b	185	ppp.rx.bufferfull=0;
nixnax	142:54d1543e23e5	186	ppp.pkt.len=0;
nixnax	154:18b2bd92f557	187	ppp.ipData.ident=10000; // easy to recognize in ip packet dumps
nixnax	142:54d1543e23e5	188	ppp.ledState=0;
nixnax	142:54d1543e23e5	189	ppp.hdlc.frameStartIndex=0;
nixnax	146:a45f49a2b29c	190	ppp.responseCounter=0;
nixnax	239:426e50519204	191	ppp.pingCount=0; // number of ICMP pings we have received
nixnax	142:54d1543e23e5	192	ppp.firstFrame=1;
nixnax	175:b4e6f8a6fe00	193	ppp.ppp = (pppHeaderType *)ppp.pkt.buf; // pointer to ppp header
nixnax	175:b4e6f8a6fe00	194	ppp.ip = (ipHeaderType *)(ppp.pkt.buf+4); // pointer to IP header
nixnax	142:54d1543e23e5	195	}
nixnax	142:54d1543e23e5	196
nixnax	142:54d1543e23e5	197	/// Toggle the LED on every second PPP packet received
nixnax	142:54d1543e23e5	198	void led1Toggle()
nixnax	142:54d1543e23e5	199	{
nixnax	142:54d1543e23e5	200	led1 = (ppp.ledState >> 1) & 1; // use second bit, in other words toggle LED only every second packet
nixnax	143:c5019f856a56	201	ppp.ledState++;
nixnax	142:54d1543e23e5	202	}
nixnax	142:54d1543e23e5	203
nixnax	179:ba2b2ddd0da5	204	/// Returns 1 after a connect message, 0 at startup or after a disconnect message
nixnax	150:3366bf3d294e	205	int connectedPpp()
nixnax	142:54d1543e23e5	206	{
nixnax	142:54d1543e23e5	207	return ppp.online;
nixnax	143:c5019f856a56	208	}
nixnax	142:54d1543e23e5	209
nixnax	179:ba2b2ddd0da5	210	/// PPP serial port receive interrupt handler.
nixnax	143:c5019f856a56	211	/// Check for available characters from the PC and read them into our own circular serial receive buffer at ppp.rx.buf.
nixnax	143:c5019f856a56	212	/// Also, if we are offline and a 0x7e frame start character is seen, we go online immediately
nixnax	179:ba2b2ddd0da5	213	void pppReceiveHandler()
nixnax	142:54d1543e23e5	214	{
nixnax	142:54d1543e23e5	215	char ch;
nixnax	179:ba2b2ddd0da5	216	while ( pc.readable() ) {
nixnax	223:917b554cb8a5	217	int localHead = (ppp.rx.head+1); // local head index
nixnax	223:917b554cb8a5	218	if (localHead > RXBUFLEN) localHead=0; // increment and wrap head index
nixnax	223:917b554cb8a5	219	if ( localHead == ppp.rx.rtail ) {
nixnax	221:1d7c32d8256b	220	ppp.rx.bufferfull = 1; // set flag if rx buffer is full
nixnax	252:b3c8c5699153	221	#define BUFFER_FULL_TRAP_YES
nixnax	243:24f899297799	222	#ifdef BUFFER_FULL_TRAP_YES
nixnax	243:24f899297799	223	while(1) {
nixnax	243:24f899297799	224	led1Toggle(); // flash LED at a slow rate to indicate buffer overfloe
nixnax	243:24f899297799	225	wait_ms(150);
nixnax	243:24f899297799	226	}
nixnax	252:b3c8c5699153	227	#else
nixnax	221:1d7c32d8256b	228	return; // don't read if rx buffer is full
nixnax	243:24f899297799	229	#endif
nixnax	142:54d1543e23e5	230	}
nixnax	142:54d1543e23e5	231	ch = pc.getc(); // read new character
nixnax	142:54d1543e23e5	232	ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax	209:aa514cd631ee	233	if (ch == 0x7E) { // check for ppp frame start character
nixnax	209:aa514cd631ee	234	if ( ppp.online == 0 ) { // check if we are offline
nixnax	209:aa514cd631ee	235	ppp.online = 1; // if we see a frame start character we immediately change status to online
nixnax	142:54d1543e23e5	236	}
nixnax	142:54d1543e23e5	237	}
nixnax	223:917b554cb8a5	238	ppp.rx.head = localHead; // update real head pointer
nixnax	221:1d7c32d8256b	239	ppp.rx.buflevel++; // update buffer level counter
nixnax	209:aa514cd631ee	240	if ( ppp.rx.buflevel > ppp.rx.maxbuflevel ) {
nixnax	221:1d7c32d8256b	241	ppp.rx.maxbuflevel = ppp.rx.buflevel; // remember the maximum usage of rx buffer
nixnax	209:aa514cd631ee	242	}
nixnax	142:54d1543e23e5	243	}
nixnax	142:54d1543e23e5	244	}
nixnax	142:54d1543e23e5	245
nixnax	145:098b6ed2f7f2	246	/// update the cumulative PPP FCS (frame check sequence)
nixnax	226:4898247048c7	247	void fcsDo(register int x)
nixnax	142:54d1543e23e5	248	{
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	220:54f45f924707	260	x>>=1;
nixnax	230:ee097c486e45	261	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	220:54f45f924707	262	x>>=1;
nixnax	230:ee097c486e45	263	ppp.fcs=((ppp.fcs^x)&1) ? (ppp.fcs>>1)^0x8408 : ppp.fcs>>1;
nixnax	142:54d1543e23e5	264	}
nixnax	142:54d1543e23e5	265
nixnax	145:098b6ed2f7f2	266	/// calculate the PPP FCS (frame check sequence) on an entire block of memory
nixnax	145:098b6ed2f7f2	267	int fcsBuf(char * buf, int size) // crc on an entire block of memory
nixnax	142:54d1543e23e5	268	{
nixnax	226:4898247048c7	269	ppp.fcs=0xffff; // fcs initial value
nixnax	145:098b6ed2f7f2	270	for(int i=0; i<size; i++)fcsDo(*buf++);
nixnax	145:098b6ed2f7f2	271	return ppp.fcs;
nixnax	142:54d1543e23e5	272	}
nixnax	142:54d1543e23e5	273
nixnax	142:54d1543e23e5	274	/// Get one character from our received PPP buffer
nixnax	142:54d1543e23e5	275	int pc_getBuf()
nixnax	142:54d1543e23e5	276	{
nixnax	142:54d1543e23e5	277	int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax	230:ee097c486e45	278	int temptail = ppp.rx.tail+1;
nixnax	230:ee097c486e45	279	if (temptail > RXBUFLEN) temptail=0;
nixnax	142:54d1543e23e5	280	ppp.rx.buflevel--;
nixnax	230:ee097c486e45	281	ppp.rx.tail = temptail;
nixnax	142:54d1543e23e5	282	return x;
nixnax	142:54d1543e23e5	283	}
nixnax	142:54d1543e23e5	284
nixnax	142:54d1543e23e5	285	/// Dump a PPP frame to the debug serial port
nixnax	142:54d1543e23e5	286	/// Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax	142:54d1543e23e5	287	/// Capture the frame's hex output in your terminal program and save as a text file
nixnax	164:c3de3d212c4b	288	/// In WireShark, use "Import Hex File". Import options are: Offset=None, Protocol=PPP.
nixnax	142:54d1543e23e5	289	void dumpPPPFrame()
nixnax	142:54d1543e23e5	290	{
nixnax	230:ee097c486e45	291	char pbuf[100];
nixnax	142:54d1543e23e5	292	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	210:a2a651249a9a	293
nixnax	142:54d1543e23e5	294	sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax	210:a2a651249a9a	295
nixnax	221:1d7c32d8256b	296	debugPuts(pbuf);
nixnax	142:54d1543e23e5	297	}
nixnax	210:a2a651249a9a	298
nixnax	142:54d1543e23e5	299	sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax	210:a2a651249a9a	300
nixnax	221:1d7c32d8256b	301	debugPuts(pbuf);
nixnax	142:54d1543e23e5	302	}
nixnax	142:54d1543e23e5	303
nixnax	142:54d1543e23e5	304	/// Process a received PPP frame
nixnax	142:54d1543e23e5	305	void processPPPFrame(int start, int end)
nixnax	142:54d1543e23e5	306	{
nixnax	226:4898247048c7	307	led1Toggle(); // change led1 state on received frames
nixnax	252:b3c8c5699153	308	ppp.pingCount++; // count any frame
nixnax	142:54d1543e23e5	309	if(start==end) {
nixnax	142:54d1543e23e5	310	return; // empty frame
nixnax	142:54d1543e23e5	311	}
nixnax	226:4898247048c7	312	ppp.fcs=0xffff; // fcs initial value
nixnax	142:54d1543e23e5	313	char * dest = ppp.pkt.buf;
nixnax	142:54d1543e23e5	314	ppp.pkt.len=0;
nixnax	142:54d1543e23e5	315	int unstuff=0;
nixnax	142:54d1543e23e5	316	int idx = start;
nixnax	142:54d1543e23e5	317	while(1) {
nixnax	142:54d1543e23e5	318	if (unstuff==0) {
nixnax	142:54d1543e23e5	319	if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax	142:54d1543e23e5	320	else {
nixnax	142:54d1543e23e5	321	*dest = ppp.rx.buf[idx];
nixnax	142:54d1543e23e5	322	ppp.pkt.len++;
nixnax	142:54d1543e23e5	323	dest++;
nixnax	145:098b6ed2f7f2	324	fcsDo(ppp.rx.buf[idx]);
nixnax	142:54d1543e23e5	325	}
nixnax	142:54d1543e23e5	326	} else { // unstuff characters prefixed with 0x7d
nixnax	142:54d1543e23e5	327	*dest = ppp.rx.buf[idx]^0x20;
nixnax	142:54d1543e23e5	328	ppp.pkt.len++;
nixnax	142:54d1543e23e5	329	dest++;
nixnax	145:098b6ed2f7f2	330	fcsDo(ppp.rx.buf[idx]^0x20);
nixnax	142:54d1543e23e5	331	unstuff=0;
nixnax	142:54d1543e23e5	332	}
nixnax	216:e3c5a5b47295	333	idx = idx+1;
nixnax	216:e3c5a5b47295	334	if (idx > RXBUFLEN) idx=0;
nixnax	142:54d1543e23e5	335	if (idx == end) break;
nixnax	142:54d1543e23e5	336	}
nixnax	145:098b6ed2f7f2	337	ppp.pkt.crc = ppp.fcs & 0xffff;
nixnax	226:4898247048c7	338	#ifdef DUMP_RECEIVED_PPP_FRAMES_YES
nixnax	226:4898247048c7	339	dumpPPPFrame(); // hex dump ALL ppp frames to the debug port
nixnax	226:4898247048c7	340	#endif
nixnax	142:54d1543e23e5	341	if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax	142:54d1543e23e5	342	determinePacketType();
nixnax	142:54d1543e23e5	343	} else {
nixnax	142:54d1543e23e5	344	#define REPORT_FCS_ERROR_YES
nixnax	142:54d1543e23e5	345	#ifdef REPORT_FCS_ERROR_YES
nixnax	230:ee097c486e45	346	char pbuf[100]; // local print buffer
nixnax	142:54d1543e23e5	347	sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax	221:1d7c32d8256b	348	debugPuts( pbuf );
nixnax	226:4898247048c7	349	#define DUMP_PPP_FRAME_ON_ERROR_NO
nixnax	226:4898247048c7	350	#ifdef DUMP_PPP_FRAME_ON_ERROR_YES
nixnax	226:4898247048c7	351	dumpPPPFrame(); // dump frames with errors in them
nixnax	226:4898247048c7	352	#endif
nixnax	142:54d1543e23e5	353	#endif
nixnax	142:54d1543e23e5	354	}
nixnax	142:54d1543e23e5	355	}
nixnax	142:54d1543e23e5	356
nixnax	142:54d1543e23e5	357	/// do PPP HDLC-like handling of special (flag) characters
nixnax	143:c5019f856a56	358	void hdlcPut(int ch)
nixnax	142:54d1543e23e5	359	{
nixnax	247:7b0a8e6fbb86	360	if ( (ch<0x20) \|\| (ch==0x7d) \|\| (ch==0x7e) \|\| (ch>0x7f) ) {
nixnax	226:4898247048c7	361	pc.putc(0x7d);
nixnax	226:4898247048c7	362	pc.putc(ch^0x20); // these characters need special handling
nixnax	142:54d1543e23e5	363	} else {
nixnax	226:4898247048c7	364	pc.putc(ch);
nixnax	142:54d1543e23e5	365	}
nixnax	142:54d1543e23e5	366	}
nixnax	142:54d1543e23e5	367
nixnax	142:54d1543e23e5	368	/// send a PPP frame in HDLC format
nixnax	144:01d98cf7738e	369	void sendPppFrame()
nixnax	143:c5019f856a56	370	{
nixnax	172:449dd7a28955	371	ppp.responseCounter++; // count the number of ppp frames we send
nixnax	145:098b6ed2f7f2	372	int crc = fcsBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax	142:54d1543e23e5	373	ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax	142:54d1543e23e5	374	ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax	226:4898247048c7	375	pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax	142:54d1543e23e5	376	for(int i=0; i<ppp.pkt.len; i++) {
nixnax	226:4898247048c7	377	// wait_us(86); // wait one character time
nixnax	210:a2a651249a9a	378
nixnax	142:54d1543e23e5	379	hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax	142:54d1543e23e5	380	}
nixnax	226:4898247048c7	381	pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax	142:54d1543e23e5	382	}
nixnax	142:54d1543e23e5	383
nixnax	143:c5019f856a56	384	/// 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	385	int bufferToIP(char * buffer)
nixnax	143:c5019f856a56	386	{
nixnax	143:c5019f856a56	387	int result=0;
nixnax	143:c5019f856a56	388	for(int i=0; i<4; i++) result = (result<<8)\|(*buffer++ & 0xff);
nixnax	143:c5019f856a56	389	return result;
nixnax	143:c5019f856a56	390	}
nixnax	143:c5019f856a56	391
nixnax	177:dab9e685af53	392	/// convert 4-byte ip address to 32-bit
nixnax	228:7fb878500862	393	unsigned int integersToIp( int a, int b, int c, int d)
nixnax	179:ba2b2ddd0da5	394	{
nixnax	177:dab9e685af53	395	return a<<24 \| b<<16 \| c<<8 \| d;
nixnax	177:dab9e685af53	396	}
nixnax	177:dab9e685af53	397
nixnax	142:54d1543e23e5	398	/// handle IPCP configuration requests
nixnax	142:54d1543e23e5	399	void ipcpConfigRequestHandler()
nixnax	142:54d1543e23e5	400	{
nixnax	230:ee097c486e45	401	debugPuts("Their IPCP Config Req, Our Ack\n");
nixnax	173:6774a0c851c4	402	if(ppp.ipcp->request[0]==3) {
nixnax	143:c5019f856a56	403	ppp.hostIP = bufferToIP(ppp.pkt.buf+10);
nixnax	173:6774a0c851c4	404	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	405	}
nixnax	143:c5019f856a56	406
nixnax	167:ff8a2d8beeb1	407	ppp.ipcp->code=2; // change code to ack
nixnax	144:01d98cf7738e	408	sendPppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax	142:54d1543e23e5	409
nixnax	230:ee097c486e45	410	debugPuts("Our IPCP Ask (no options)\n");
nixnax	167:ff8a2d8beeb1	411	ppp.ipcp->code=1; // change code to request
nixnax	167:ff8a2d8beeb1	412	ppp.ipcp->lengthR = __REV16( 4 ); // 4 is minimum length - no options in this request
nixnax	167:ff8a2d8beeb1	413	ppp.pkt.len=4+4+2; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax	144:01d98cf7738e	414	sendPppFrame(); // send our request
nixnax	142:54d1543e23e5	415	}
nixnax	142:54d1543e23e5	416
nixnax	142:54d1543e23e5	417	/// handle IPCP acknowledge (do nothing)
nixnax	142:54d1543e23e5	418	void ipcpAckHandler()
nixnax	142:54d1543e23e5	419	{
nixnax	230:ee097c486e45	420	debugPuts("Their IPCP Grant\n");
nixnax	142:54d1543e23e5	421	}
nixnax	142:54d1543e23e5	422
nixnax	143:c5019f856a56	423	/// Handle IPCP NACK by sending our suggested IP address if there is an IP involved.
nixnax	143:c5019f856a56	424	/// 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	425	void ipcpNackHandler()
nixnax	142:54d1543e23e5	426	{
nixnax	230:ee097c486e45	427	debugPuts("Their IPCP Nack\n");
nixnax	173:6774a0c851c4	428	if (ppp.ipcp->request[0]==3) { // check if the NACK contains an IP address parameter
nixnax	167:ff8a2d8beeb1	429	ppp.ipcp->code=1; // assume the NACK contains our "suggested" IP address
nixnax	144:01d98cf7738e	430	sendPppFrame(); // let's request this IP address as ours
nixnax	230:ee097c486e45	431	debugPuts("Our IPCP ACK (received an IP)\n");
nixnax	146:a45f49a2b29c	432	} else { // if it's not an IP nack we ignore it
nixnax	230:ee097c486e45	433	debugPuts("IPCP Nack Ignored\n");
nixnax	146:a45f49a2b29c	434	}
nixnax	142:54d1543e23e5	435	}
nixnax	142:54d1543e23e5	436
nixnax	142:54d1543e23e5	437	/// handle all other IPCP requests (by ignoring them)
nixnax	142:54d1543e23e5	438	void ipcpDefaultHandler()
nixnax	142:54d1543e23e5	439	{
nixnax	230:ee097c486e45	440	debugPuts("Their IPCP Other\n");
nixnax	142:54d1543e23e5	441	}
nixnax	142:54d1543e23e5	442
nixnax	142:54d1543e23e5	443	/// process an incoming IPCP packet
nixnax	142:54d1543e23e5	444	void IPCPframe()
nixnax	142:54d1543e23e5	445	{
nixnax	167:ff8a2d8beeb1	446	int action = ppp.ipcp->code; // packet type is here
nixnax	167:ff8a2d8beeb1	447	switch (action) {
nixnax	142:54d1543e23e5	448	case 1:
nixnax	142:54d1543e23e5	449	ipcpConfigRequestHandler();
nixnax	142:54d1543e23e5	450	break;
nixnax	142:54d1543e23e5	451	case 2:
nixnax	142:54d1543e23e5	452	ipcpAckHandler();
nixnax	142:54d1543e23e5	453	break;
nixnax	142:54d1543e23e5	454	case 3:
nixnax	142:54d1543e23e5	455	ipcpNackHandler();
nixnax	142:54d1543e23e5	456	break;
nixnax	142:54d1543e23e5	457	default:
nixnax	142:54d1543e23e5	458	ipcpDefaultHandler();
nixnax	142:54d1543e23e5	459	}
nixnax	142:54d1543e23e5	460	}
nixnax	142:54d1543e23e5	461
nixnax	142:54d1543e23e5	462	/// perform a 16-bit checksum. if the byte count is odd, stuff in an extra zero byte.
nixnax	161:d59f778bc8ab	463	unsigned int dataCheckSum(char * ptr, int len, int restart)
nixnax	142:54d1543e23e5	464	{
nixnax	159:4d1bf96a59cd	465	unsigned int i,hi,lo;
nixnax	142:54d1543e23e5	466	unsigned char placeHolder;
nixnax	161:d59f778bc8ab	467	if (restart) ppp.sum=0;
nixnax	142:54d1543e23e5	468	if (len&1) {
nixnax	142:54d1543e23e5	469	placeHolder = ptr[len];
nixnax	142:54d1543e23e5	470	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	471	}
nixnax	142:54d1543e23e5	472	i=0;
nixnax	142:54d1543e23e5	473	while ( i<len ) {
nixnax	210:a2a651249a9a	474
nixnax	142:54d1543e23e5	475	hi = ptr[i++];
nixnax	142:54d1543e23e5	476	lo = ptr[i++];
nixnax	159:4d1bf96a59cd	477	ppp.sum = ppp.sum + ((hi<<8)\|lo);
nixnax	142:54d1543e23e5	478	}
nixnax	142:54d1543e23e5	479	if (len&1) {
nixnax	142:54d1543e23e5	480	ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax	142:54d1543e23e5	481	}
nixnax	159:4d1bf96a59cd	482	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16);
nixnax	159:4d1bf96a59cd	483	ppp.sum = (ppp.sum & 0xffff) + (ppp.sum>>16); // sum one more time to catch any carry from the carry
nixnax	159:4d1bf96a59cd	484	return ~ppp.sum;
nixnax	142:54d1543e23e5	485	}
nixnax	142:54d1543e23e5	486
nixnax	142:54d1543e23e5	487	/// perform the checksum on an IP header
nixnax	146:a45f49a2b29c	488	void IpHeaderCheckSum()
nixnax	142:54d1543e23e5	489	{
nixnax	161:d59f778bc8ab	490	ppp.ip->checksumR=0; // zero the checsum in the IP header
nixnax	161:d59f778bc8ab	491	int len = 4 * ppp.ip->headerLength; // length of IP header in bytes
nixnax	161:d59f778bc8ab	492	unsigned int sum = dataCheckSum(ppp.ipStart,len,1);
nixnax	161:d59f778bc8ab	493	ppp.ip->checksumR = __REV16( sum ); // insert fresh checksum
nixnax	146:a45f49a2b29c	494	}
nixnax	146:a45f49a2b29c	495
nixnax	147:0f40005cbc5f	496	/// swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	497	void swapIpAddresses()
nixnax	147:0f40005cbc5f	498	{
nixnax	162:594729c0e5c1	499	unsigned int tempHold;
nixnax	162:594729c0e5c1	500	tempHold = ppp.ip->srcAdrR; // tempHold <- source IP
nixnax	162:594729c0e5c1	501	ppp.ip->srcAdrR = ppp.ip->dstAdrR; // source <- dest
nixnax	162:594729c0e5c1	502	ppp.ip->dstAdrR = tempHold; // dest <- tempHold*/
nixnax	147:0f40005cbc5f	503	}
nixnax	147:0f40005cbc5f	504
nixnax	149:969d98f6fb88	505	/// swap the IP source and destination ports
nixnax	149:969d98f6fb88	506	void swapIpPorts()
nixnax	149:969d98f6fb88	507	{
nixnax	173:6774a0c851c4	508	int headerSizeIP = 4 * (ppp.ip->headerLength); // calculate size of IP header
nixnax	173:6774a0c851c4	509	char * ipSrcPort = ppp.ipStart + headerSizeIP + 0; // ip source port location
nixnax	173:6774a0c851c4	510	char * ipDstPort = ppp.ipStart + headerSizeIP + 2; // ip destin port location
nixnax	149:969d98f6fb88	511	char tempHold[2];
nixnax	149:969d98f6fb88	512	memcpy(tempHold, ipSrcPort,2); // tempHold <- source
nixnax	149:969d98f6fb88	513	memcpy(ipSrcPort,ipDstPort,2); // source <- dest
nixnax	149:969d98f6fb88	514	memcpy(ipDstPort,tempHold, 2); // dest <- tempHold
nixnax	149:969d98f6fb88	515	}
nixnax	149:969d98f6fb88	516
nixnax	170:3d3b2126181c	517	/// Build the "pseudo header" required for UDP and TCP, then calculate its checksum
nixnax	170:3d3b2126181c	518	void checkSumPseudoHeader( unsigned int packetLength )
nixnax	170:3d3b2126181c	519	{
nixnax	170:3d3b2126181c	520	// 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	521	pseudoIpHeaderType pseudoHeader; // create pseudo header
nixnax	170:3d3b2126181c	522	pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
nixnax	170:3d3b2126181c	523	pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
nixnax	170:3d3b2126181c	524	pseudoHeader.zero = 0; // zero byte
nixnax	170:3d3b2126181c	525	pseudoHeader.protocol = ppp.ip->protocol; // protocol number (udp or tcp)
nixnax	170:3d3b2126181c	526	pseudoHeader.lengthR = __REV16( packetLength ); // size of tcp or udp packet
nixnax	170:3d3b2126181c	527	dataCheckSum(pseudoHeader.start, 12, 1); // calculate this header's checksum
nixnax	170:3d3b2126181c	528	}
nixnax	170:3d3b2126181c	529
nixnax	171:46b36d4edd1d	530	/// initialize an IP packet to send
nixnax	171:46b36d4edd1d	531	void initIP (unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, unsigned int protocol)
nixnax	171:46b36d4edd1d	532	{
nixnax	171:46b36d4edd1d	533	ppp.ppp->address = 0xff;
nixnax	171:46b36d4edd1d	534	ppp.ppp->control = 3;
nixnax	171:46b36d4edd1d	535	ppp.ppp->protocolR = __REV16( 0x0021 );
nixnax	171:46b36d4edd1d	536	ppp.ip->version = 4;
nixnax	171:46b36d4edd1d	537	ppp.ip->headerLength = 5; // 5 words = 20 bytes
nixnax	171:46b36d4edd1d	538	ppp.ip->identR = __REV16(ppp.ipData.ident++); // insert our ident
nixnax	171:46b36d4edd1d	539	ppp.ip->dontFragment=1;
nixnax	171:46b36d4edd1d	540	ppp.ip->ttl=128;
nixnax	171:46b36d4edd1d	541	ppp.ip->protocol = protocol; // udp
nixnax	171:46b36d4edd1d	542	ppp.ip->srcAdrR = __REV(srcIp);
nixnax	171:46b36d4edd1d	543	ppp.ip->dstAdrR = __REV(dstIp);
nixnax	171:46b36d4edd1d	544	ppp.udpStart = ppp.ipStart + 20; // calculate start of udp header
nixnax	171:46b36d4edd1d	545	ppp.udp->srcPortR = __REV16(srcPort); // source port
nixnax	171:46b36d4edd1d	546	ppp.udp->dstPortR = __REV16(dstPort); // dest port
nixnax	171:46b36d4edd1d	547	}
nixnax	171:46b36d4edd1d	548
nixnax	171:46b36d4edd1d	549
nixnax	171:46b36d4edd1d	550	/// Build a UDP packet from scratch
nixnax	171:46b36d4edd1d	551	void sendUdp(unsigned int srcIp, unsigned int dstIp, unsigned int srcPort, unsigned int dstPort, char * message,int msgLen)
nixnax	171:46b36d4edd1d	552	{
nixnax	171:46b36d4edd1d	553	struct {
nixnax	171:46b36d4edd1d	554	unsigned int ipAll; // length of entire ip packet
nixnax	171:46b36d4edd1d	555	unsigned int ipHeader; // length of ip header
nixnax	171:46b36d4edd1d	556	unsigned int udpAll; // length of entire udp packet
nixnax	171:46b36d4edd1d	557	unsigned int udpData; // length of udp data segment
nixnax	171:46b36d4edd1d	558	} len;
nixnax	171:46b36d4edd1d	559	len.ipHeader = 20; // ip header length
nixnax	171:46b36d4edd1d	560	len.udpData = msgLen; // udp data size
nixnax	171:46b36d4edd1d	561	len.udpAll = len.udpData+8; // update local udp packet length
nixnax	171:46b36d4edd1d	562	len.ipAll = len.ipHeader + len.udpAll; // update IP Length
nixnax	171:46b36d4edd1d	563	initIP(srcIp, dstIp, srcPort, dstPort, 17); // init a UDP packet
nixnax	171:46b36d4edd1d	564	ppp.ip->lengthR = __REV16(len.ipAll); // update IP length in buffer
nixnax	171:46b36d4edd1d	565	ppp.udpStart = ppp.ipStart + len.ipHeader; // calculate start of udp header
nixnax	171:46b36d4edd1d	566	memcpy( ppp.udp->data, message, len.udpData ); // copy the message to the buffer
nixnax	171:46b36d4edd1d	567	ppp.udp->lengthR = __REV16(len.udpAll); // update UDP length in buffer
nixnax	171:46b36d4edd1d	568	ppp.pkt.len = len.ipAll+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	569	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	570	checkSumPseudoHeader( len.udpAll ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	571	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	572	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,len.udpAll, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	573	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	574	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	575	}
nixnax	171:46b36d4edd1d	576
nixnax	146:a45f49a2b29c	577	/// Process an incoming UDP packet.
nixnax	146:a45f49a2b29c	578	/// If the packet starts with the string "echo " or "test" we echo back a special packet
nixnax	146:a45f49a2b29c	579	void UDPpacket()
nixnax	146:a45f49a2b29c	580	{
nixnax	163:d1b4328e9f08	581	struct {
nixnax	163:d1b4328e9f08	582	unsigned int all; // length of entire ip packet
nixnax	163:d1b4328e9f08	583	unsigned int header; // length of ip header
nixnax	163:d1b4328e9f08	584	} ipLength;
nixnax	163:d1b4328e9f08	585
nixnax	163:d1b4328e9f08	586	struct {
nixnax	165:c47826d07e0d	587	unsigned int all; // length of entire udp packet
nixnax	163:d1b4328e9f08	588	unsigned int data; // length of udp data segment
nixnax	163:d1b4328e9f08	589	} udpLength;
nixnax	163:d1b4328e9f08	590
nixnax	163:d1b4328e9f08	591	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	163:d1b4328e9f08	592	ppp.udpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	171:46b36d4edd1d	593	udpLength.all = __REV16( ppp.udp->lengthR ); // size of udp packet
nixnax	163:d1b4328e9f08	594	udpLength.data = udpLength.all - 8; // size of udp data
nixnax	147:0f40005cbc5f	595
nixnax	146:a45f49a2b29c	596	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	171:46b36d4edd1d	597	char * srcIP = ppp.ip->srcAdrPtr; // IP source
nixnax	171:46b36d4edd1d	598	char * dstIP = ppp.ip->dstAdrPtr; //IP destination
nixnax	163:d1b4328e9f08	599
nixnax	171:46b36d4edd1d	600	unsigned int udpSrcPort = __REV16( ppp.udp->srcPortR ); // integer of UDP source port
nixnax	171:46b36d4edd1d	601	unsigned int udpDstPort = __REV16( ppp.udp->dstPortR ); // integer of UDP dest port
nixnax	163:d1b4328e9f08	602
nixnax	163:d1b4328e9f08	603	if(v0) {
nixnax	163:d1b4328e9f08	604	debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],udpSrcPort);
nixnax	163:d1b4328e9f08	605	debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],udpDstPort);
nixnax	163:d1b4328e9f08	606	debugPrintf("Len %03d", udpLength);
nixnax	163:d1b4328e9f08	607	}
nixnax	146:a45f49a2b29c	608	if (v1) {
nixnax	163:d1b4328e9f08	609	int printSize = udpLength.data;
nixnax	146:a45f49a2b29c	610	if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax	146:a45f49a2b29c	611	for (int i=0; i<printSize; i++) {
nixnax	163:d1b4328e9f08	612	char ch = ppp.udp->data[i];
nixnax	146:a45f49a2b29c	613	if (ch>31 && ch<127) {
nixnax	146:a45f49a2b29c	614	debugPrintf("%c", ch);
nixnax	146:a45f49a2b29c	615	} else {
nixnax	230:ee097c486e45	616	debugPuts("_");
nixnax	146:a45f49a2b29c	617	}
nixnax	146:a45f49a2b29c	618	}
nixnax	146:a45f49a2b29c	619	}
nixnax	230:ee097c486e45	620	if (v0) debugPuts("\n");
nixnax	146:a45f49a2b29c	621	#endif
nixnax	163:d1b4328e9f08	622	int echoFound = !strncmp(ppp.udp->data,"echo ",5); // true if UDP message starts with "echo "
nixnax	163:d1b4328e9f08	623	int testFound = !strncmp(ppp.udp->data,"test" ,4); // true if UDP message starts with "test"
nixnax	146:a45f49a2b29c	624	if ( (echoFound) \|\| (testFound)) { // if the UDP message starts with "echo " or "test" we answer back
nixnax	146:a45f49a2b29c	625	if (echoFound) {
nixnax	171:46b36d4edd1d	626	swapIpAddresses(); // swap IP source and destination
nixnax	171:46b36d4edd1d	627	swapIpPorts(); // swap IP source and destination ports
nixnax	163:d1b4328e9f08	628	memcpy(ppp.udp->data,"Got{",4); // in the UDP data modify "echo" to "Got:"
nixnax	170:3d3b2126181c	629	int n=0;
nixnax	230:ee097c486e45	630	#define IDENTIFY_UDP_SERVER_NO
nixnax	230:ee097c486e45	631	#ifdef IDENTIFY_UDP_SERVER_YES
nixnax	170:3d3b2126181c	632	n=n+sprintf(n+ppp.udp->data+udpLength.data, "} UDP Server: PPP-Blinky\n"); // an appendix
nixnax	230:ee097c486e45	633	#endif
nixnax	168:c77eb908042a	634	udpLength.data = udpLength.data + n; // update udp data size with the size of the appendix
nixnax	171:46b36d4edd1d	635	// we may have changed data length, update all the lengths
nixnax	171:46b36d4edd1d	636	udpLength.all = udpLength.data+8; // update local udp packet length
nixnax	171:46b36d4edd1d	637	ipLength.all = ipLength.header + udpLength.all; // update IP Length
nixnax	171:46b36d4edd1d	638	ppp.ip->lengthR = __REV16(ipLength.all); // update IP length in buffer
nixnax	171:46b36d4edd1d	639	ppp.udp->lengthR = __REV16(udpLength.all); // update UDP length in buffer
nixnax	171:46b36d4edd1d	640	ppp.pkt.len = ipLength.all+2+4; // update ppp packet length
nixnax	171:46b36d4edd1d	641	IpHeaderCheckSum(); // refresh IP header checksum
nixnax	171:46b36d4edd1d	642	checkSumPseudoHeader( udpLength.all ); // get the UDP pseudo-header checksum
nixnax	171:46b36d4edd1d	643	ppp.udp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	171:46b36d4edd1d	644	unsigned int pseudoHeaderSum=dataCheckSum(ppp.udpStart,udpLength.all, 0); // continue the TCP checksum on the whole TCP packet
nixnax	171:46b36d4edd1d	645	ppp.udp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	171:46b36d4edd1d	646	sendPppFrame(); // send the UDP message back
nixnax	171:46b36d4edd1d	647	} else if ( testFound ) {
nixnax	171:46b36d4edd1d	648	unsigned int sI = __REV( ppp.ip->srcAdrR );
nixnax	171:46b36d4edd1d	649	unsigned int dI = __REV( ppp.ip->dstAdrR );
nixnax	171:46b36d4edd1d	650	unsigned int sp = __REV16( ppp.udp->srcPortR );
nixnax	171:46b36d4edd1d	651	unsigned int dp = __REV16( ppp.udp->dstPortR );
nixnax	172:449dd7a28955	652	int n=sprintf(ppp.pkt.buf+200,"Response Count %d\n", ppp.responseCounter);
nixnax	171:46b36d4edd1d	653	sendUdp(dI,sI,dp,sp,ppp.pkt.buf+200,n); // build a udp packet from the ground up
nixnax	146:a45f49a2b29c	654	}
nixnax	146:a45f49a2b29c	655	}
nixnax	142:54d1543e23e5	656	}
nixnax	142:54d1543e23e5	657
nixnax	174:e5a3f16421a5	658	/// UDP demo that sends a udp packet containing a character received from the second debug serial port.
nixnax	174:e5a3f16421a5	659	/// Sends a 48 byte IP/UDP header for every 1 byte of data so line-mode would probably be better.
nixnax	178:3f17aa0ce5ce	660	/// If you want ip packets from ppp blinky to be routed to other networks, ensure you have ip routing enabled.
nixnax	178:3f17aa0ce5ce	661	/// See http://www.wikihow.com/Enable-IP-Routing.
nixnax	179:ba2b2ddd0da5	662	/// Also ensure that the firewall on the receiving machine has the receiving UDP port (12345 in this example) enabled.
nixnax	179:ba2b2ddd0da5	663	/// The netcat UDP receive command on the remote host would be: nc -ul 12345
nixnax	174:e5a3f16421a5	664	void sendUdpData()
nixnax	174:e5a3f16421a5	665	{
nixnax	174:e5a3f16421a5	666	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	179:ba2b2ddd0da5	667	if (ppp.online) {
nixnax	179:ba2b2ddd0da5	668	if (xx.readable()) {
nixnax	179:ba2b2ddd0da5	669	char inchar = xx.getc();
nixnax	179:ba2b2ddd0da5	670	xx.putc( inchar ); // echo the received character on the debug serial port
nixnax	228:7fb878500862	671	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	672	}
nixnax	174:e5a3f16421a5	673	}
nixnax	174:e5a3f16421a5	674	#endif
nixnax	174:e5a3f16421a5	675	}
nixnax	174:e5a3f16421a5	676
nixnax	142:54d1543e23e5	677	/// handle a PING ICMP (internet control message protocol) packet
nixnax	142:54d1543e23e5	678	void ICMPpacket() // internet control message protocol
nixnax	142:54d1543e23e5	679	{
nixnax	165:c47826d07e0d	680	struct {
nixnax	165:c47826d07e0d	681	unsigned int all; // length of entire ip packet
nixnax	165:c47826d07e0d	682	unsigned int header; // length of ip header
nixnax	165:c47826d07e0d	683	} ipLength;
nixnax	165:c47826d07e0d	684	struct {
nixnax	165:c47826d07e0d	685	unsigned int all; // length of entire udp packet
nixnax	165:c47826d07e0d	686	unsigned int data; // length of udp data segment
nixnax	165:c47826d07e0d	687	} icmpLength;
nixnax	165:c47826d07e0d	688	ipLength.all = __REV16( ppp.ip->lengthR ); // length of ip packet
nixnax	165:c47826d07e0d	689	ipLength.header = 4 * ppp.ip->headerLength; // length of ip header
nixnax	165:c47826d07e0d	690	ppp.icmpStart = ppp.ipStart + ipLength.header; // calculate start of udp header
nixnax	165:c47826d07e0d	691	icmpLength.all = ipLength.all - ipLength.header; // length of icmp packet
nixnax	165:c47826d07e0d	692	icmpLength.data = icmpLength.all - 8; // length of icmp data
nixnax	142:54d1543e23e5	693	#define ICMP_TYPE_PING_REQUEST 8
nixnax	165:c47826d07e0d	694	if ( ppp.icmp->type == ICMP_TYPE_PING_REQUEST ) {
nixnax	165:c47826d07e0d	695	ppp.ip->ttl--; // decrement time to live (so we have to update header checksum)
nixnax	253:ee1044976b2c	696	//ppp.pingCount++; // count how many times we get pinged
nixnax	147:0f40005cbc5f	697	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	167:ff8a2d8beeb1	698	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	699	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	165:c47826d07e0d	700	int icmpIdent = __REV16( ppp.ip->identR ); // byte reversed - big endian
nixnax	165:c47826d07e0d	701	int icmpSequence = __REV16( ppp.icmp->sequenceR ); // byte reversed - big endian
nixnax	142:54d1543e23e5	702	if(1) {
nixnax	230:ee097c486e45	703	char pbuf[100];
nixnax	210:a2a651249a9a	704
nixnax	142:54d1543e23e5	705	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	706	debugPuts( pbuf );
nixnax	210:a2a651249a9a	707
nixnax	142:54d1543e23e5	708	sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax	210:a2a651249a9a	709
nixnax	221:1d7c32d8256b	710	debugPuts( pbuf );
nixnax	142:54d1543e23e5	711	}
nixnax	142:54d1543e23e5	712	#endif
nixnax	147:0f40005cbc5f	713	swapIpAddresses(); // swap the IP source and destination addresses
nixnax	147:0f40005cbc5f	714	IpHeaderCheckSum(); // new ip header checksum (required because we changed TTL)
nixnax	142:54d1543e23e5	715	#define ICMP_TYPE_ECHO_REPLY 0
nixnax	165:c47826d07e0d	716	ppp.icmp->type = ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax	165:c47826d07e0d	717	ppp.icmp->checkSumR = 0; // zero the checksum for recalculation
nixnax	165:c47826d07e0d	718	unsigned int sum = dataCheckSum(ppp.icmpStart, icmpLength.all, 1); // icmp checksum
nixnax	165:c47826d07e0d	719	ppp.icmp->checkSumR = __REV16( sum ); // save big-endian icmp checksum
nixnax	226:4898247048c7	720	#define DUMP_ICMP_PACKETS_NO
nixnax	226:4898247048c7	721	#ifdef DUMP_ICMP_PACKETS_YES
nixnax	165:c47826d07e0d	722	int printSize = icmpLength.data; // exclude size of icmp header
nixnax	142:54d1543e23e5	723	if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax	226:4898247048c7	724	for (int i=0; i<printSize; i++) {
nixnax	226:4898247048c7	725	char ch = ppp.icmp->data[i];
nixnax	226:4898247048c7	726	if (ch>31 && ch<127) {
nixnax	226:4898247048c7	727	debugPutc(ch);
nixnax	226:4898247048c7	728	} else {
nixnax	226:4898247048c7	729	debugPutc('_'); // for non-printable characters
nixnax	142:54d1543e23e5	730	}
nixnax	142:54d1543e23e5	731	}
nixnax	226:4898247048c7	732	debugPutc('\n');
nixnax	226:4898247048c7	733	#endif
nixnax	144:01d98cf7738e	734	sendPppFrame(); // reply to the ping
nixnax	142:54d1543e23e5	735	} else {
nixnax	142:54d1543e23e5	736	if (v0) {
nixnax	165:c47826d07e0d	737	debugPrintf("ICMP type=%x \n", ppp.icmp->type);
nixnax	142:54d1543e23e5	738	}
nixnax	142:54d1543e23e5	739	}
nixnax	142:54d1543e23e5	740	}
nixnax	142:54d1543e23e5	741
nixnax	142:54d1543e23e5	742	/// handle an IGMP (internet group managment protocol) packet (by ignoring it)
nixnax	142:54d1543e23e5	743	void IGMPpacket()
nixnax	142:54d1543e23e5	744	{
nixnax	142:54d1543e23e5	745	if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax	142:54d1543e23e5	746	}
nixnax	142:54d1543e23e5	747
nixnax	142:54d1543e23e5	748	/// dump the header of an IP pakcet on the (optional) debug serial port
nixnax	142:54d1543e23e5	749	void dumpHeaderIP (int outGoing)
nixnax	142:54d1543e23e5	750	{
nixnax	142:54d1543e23e5	751	#if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	210:a2a651249a9a	752
nixnax	155:9c6a1d249e26	753	int IPv4Id = __REV16(ppp.ip->identR);
nixnax	230:ee097c486e45	754	char pbuf[100]; // local print buffer
nixnax	142:54d1543e23e5	755	int n=0;
nixnax	142:54d1543e23e5	756	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	142:54d1543e23e5	757	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	758	#define DUMP_FULL_IP_ADDRESS_YES
nixnax	142:54d1543e23e5	759	#ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax	167:ff8a2d8beeb1	760	char * srcAdr = ppp.ip->srcAdrPtr;
nixnax	167:ff8a2d8beeb1	761	char * dstAdr = ppp.ip->dstAdrPtr;
nixnax	142:54d1543e23e5	762	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	763	#endif
nixnax	221:1d7c32d8256b	764	debugPuts( pbuf );
nixnax	142:54d1543e23e5	765	#ifndef TCP_HEADER_DUMP_YES
nixnax	221:1d7c32d8256b	766	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	767	#endif
nixnax	142:54d1543e23e5	768	#endif
nixnax	142:54d1543e23e5	769	}
nixnax	142:54d1543e23e5	770
nixnax	142:54d1543e23e5	771	/// dump a TCP header on the optional debug serial port
nixnax	142:54d1543e23e5	772	void dumpHeaderTCP(int outGoing)
nixnax	142:54d1543e23e5	773	{
nixnax	142:54d1543e23e5	774	#if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax	155:9c6a1d249e26	775	char flagString[9]; // text string presenting the 8 most important TCP flags
nixnax	142:54d1543e23e5	776	#define PRINT_ALL_TCP_FLAGS_YES
nixnax	142:54d1543e23e5	777	#ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax	155:9c6a1d249e26	778	memset(flagString,'.', 8); // fill string with "........"
nixnax	156:163c23249731	779	if (ppp.tcp->flag.fin) flagString[7]='F';
nixnax	156:163c23249731	780	if (ppp.tcp->flag.syn) flagString[6]='S';
nixnax	156:163c23249731	781	if (ppp.tcp->flag.rst) flagString[5]='R';
nixnax	156:163c23249731	782	if (ppp.tcp->flag.psh) flagString[4]='P';
nixnax	156:163c23249731	783	if (ppp.tcp->flag.ack) flagString[3]='A';
nixnax	156:163c23249731	784	if (ppp.tcp->flag.urg) flagString[2]='U';
nixnax	156:163c23249731	785	if (ppp.tcp->flag.ece) flagString[1]='E';
nixnax	156:163c23249731	786	if (ppp.tcp->flag.cwr) flagString[0]='C';
nixnax	155:9c6a1d249e26	787	flagString[8]=0; // null terminate string
nixnax	142:54d1543e23e5	788	#else
nixnax	156:163c23249731	789	if (ppp.tcp->flag.ack) flagString[0]='A'; // choose only the most important flag to print
nixnax	156:163c23249731	790	if (ppp.tcp->flag.syn) flagString[0]='S';
nixnax	156:163c23249731	791	if (ppp.tcp->flag.fin) flagString[0]='F';
nixnax	156:163c23249731	792	if (ppp.tcp->flag.psh) flagString[0]='P';
nixnax	156:163c23249731	793	if (ppp.tcp->flag.rst) flagString[0]='R';
nixnax	155:9c6a1d249e26	794	flagString[1]=0; // null terminate string
nixnax	142:54d1543e23e5	795	#endif
nixnax	221:1d7c32d8256b	796	debugPuts( flagString );
nixnax	142:54d1543e23e5	797	#define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	142:54d1543e23e5	798	#ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax	221:1d7c32d8256b	799	debugPuts("\x1b[30m\n"); // write a black color and newline after every packet
nixnax	160:bd701ad564cb	800	#else
nixnax	221:1d7c32d8256b	801	debugPuts("\x1b[30m"); // write a black color after every packet
nixnax	142:54d1543e23e5	802	#endif
nixnax	156:163c23249731	803	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	804	debugPutc('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
nixnax	142:54d1543e23e5	805	}
nixnax	142:54d1543e23e5	806	#endif
nixnax	142:54d1543e23e5	807	}
nixnax	142:54d1543e23e5	808
nixnax	143:c5019f856a56	809	/// Encode a buffer in base-64
nixnax	184:4133f557d4d4	810	const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax	142:54d1543e23e5	811	void enc64(char * in, char * out, int len)
nixnax	142:54d1543e23e5	812	{
nixnax	142:54d1543e23e5	813	int i,j,a,b,c;
nixnax	142:54d1543e23e5	814	i=0;
nixnax	142:54d1543e23e5	815	j=0;
nixnax	142:54d1543e23e5	816	while(1) {
nixnax	142:54d1543e23e5	817	if (i<len) {
nixnax	142:54d1543e23e5	818	a = in[i++];
nixnax	142:54d1543e23e5	819	out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax	142:54d1543e23e5	820	} else break;
nixnax	142:54d1543e23e5	821	if (i<len) {
nixnax	142:54d1543e23e5	822	b = in[i++];
nixnax	142:54d1543e23e5	823	out[j++] = lut[ ( (a << 4) & 0x30) \| ( (b >> 4) & 0x0f) ];
nixnax	142:54d1543e23e5	824	out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax	142:54d1543e23e5	825	} else out[j++] = '=';
nixnax	142:54d1543e23e5	826	if (i<len) {
nixnax	142:54d1543e23e5	827	c = in[i++];
nixnax	142:54d1543e23e5	828	j--;
nixnax	142:54d1543e23e5	829	out[j++] = lut[ ( (b << 2) & 0x3c) \| ( (c >> 6) & 0x03) ];
nixnax	142:54d1543e23e5	830	out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax	142:54d1543e23e5	831	} else out[j++] = '=';
nixnax	142:54d1543e23e5	832	}
nixnax	142:54d1543e23e5	833	out[j]=0;
nixnax	142:54d1543e23e5	834	}
nixnax	142:54d1543e23e5	835
nixnax	160:bd701ad564cb	836	/// Handle a request for an http websocket.
nixnax	160:bd701ad564cb	837	/// 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	838	int webSocketHandler(char * dataStart)
nixnax	142:54d1543e23e5	839	{
nixnax	142:54d1543e23e5	840	int n=0; // byte counter
nixnax	184:4133f557d4d4	841	char * key = strstr(dataStart, "Sec-WebSocket-Key:"); // search for the key in the payload
nixnax	142:54d1543e23e5	842	if (key != NULL) {
nixnax	184:4133f557d4d4	843	key = key + 18; // skip over the key ident string "Sec-WebSocket-Key:"
nixnax	221:1d7c32d8256b	844	if (v0) debugPuts("WebSocket Request\n");
nixnax	184:4133f557d4d4	845	while ( strchr(lut, *key) == NULL) key++; // skip non-valid base-64 characters (whitespace)
nixnax	184:4133f557d4d4	846	char challenge [80];
nixnax	184:4133f557d4d4	847	int i=0;
nixnax	184:4133f557d4d4	848	char * copyTo = challenge;
nixnax	184:4133f557d4d4	849	while (strchr(lut, *key) != NULL) { // copy while we see valid base-64 characters
nixnax	184:4133f557d4d4	850	if (i++ >40) break; // prevent buffer overflow
nixnax	184:4133f557d4d4	851	copyTo++ = key++; // copy next valid base-64 character
nixnax	184:4133f557d4d4	852	}
nixnax	184:4133f557d4d4	853	strcpy(copyTo,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // append websocket gui code
nixnax	226:4898247048c7	854	#define DUMP_WEBSOCKET_CHALLENGE_NO
nixnax	226:4898247048c7	855	#ifdef DUMP_WEBSOCKET_CHALLENGE_YES
nixnax	226:4898247048c7	856	debugPrintf("Challenge is %s\n", challenge); // the string we hash for the challenge
nixnax	227:f87156f9ef11	857	#endif
nixnax	142:54d1543e23e5	858	char shaOutput [20]; // sha1 output
nixnax	184:4133f557d4d4	859	sha1( shaOutput, challenge, strlen(challenge)); // hash the challenge
nixnax	142:54d1543e23e5	860	char encOut[50];
nixnax	184:4133f557d4d4	861	enc64( shaOutput, encOut, 20); // base-64 encode
nixnax	142:54d1543e23e5	862	char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax	142:54d1543e23e5	863	char * version = challenge;
nixnax	184:4133f557d4d4	864	strncpy(version, versionstring,70); // copy their version string
nixnax	142:54d1543e23e5	865	*strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax	240:d7a01533397d	866	memset(dataStart,0,500); // blank out old data before sending the websocket response header
nixnax	142:54d1543e23e5	867	n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax	142:54d1543e23e5	868	n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax	142:54d1543e23e5	869	n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax	142:54d1543e23e5	870	n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax	142:54d1543e23e5	871	n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax	142:54d1543e23e5	872	n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax	142:54d1543e23e5	873	n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax	142:54d1543e23e5	874	}
nixnax	142:54d1543e23e5	875	return n; // this response should satisfy a web browser's websocket protocol request
nixnax	142:54d1543e23e5	876	}
nixnax	142:54d1543e23e5	877
nixnax	142:54d1543e23e5	878	#define TCP_FLAG_ACK (1<<4)
nixnax	142:54d1543e23e5	879	#define TCP_FLAG_SYN (1<<1)
nixnax	142:54d1543e23e5	880	#define TCP_FLAG_PSH (1<<3)
nixnax	142:54d1543e23e5	881	#define TCP_FLAG_RST (1<<2)
nixnax	142:54d1543e23e5	882	#define TCP_FLAG_FIN (1<<0)
nixnax	142:54d1543e23e5	883
nixnax	142:54d1543e23e5	884	/// respond to an HTTP request
nixnax	185:4cd8f91e9d49	885	int httpResponse(char * dataStart, int * flags)
nixnax	142:54d1543e23e5	886	{
nixnax	142:54d1543e23e5	887	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	888	n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax	160:bd701ad564cb	889	if (n>0) return n; // if n>0 we already have a response, so return
nixnax	142:54d1543e23e5	890
nixnax	142:54d1543e23e5	891	int nHeader; // byte size of HTTP header
nixnax	142:54d1543e23e5	892	int contentLengthStart; // index where HTML starts
nixnax	142:54d1543e23e5	893	int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax	185:4cd8f91e9d49	894	*flags = TCP_FLAG_ACK \| TCP_FLAG_FIN; // the default case is that we close the connection
nixnax	142:54d1543e23e5	895
nixnax	142:54d1543e23e5	896	httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax	142:54d1543e23e5	897	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	898	httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	899	httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax	142:54d1543e23e5	900	// for example, you could try this using netcat (nc): echo "GET /x" \| nc 172.10.10.2
nixnax	210:a2a651249a9a	901	if( (httpGetRoot==0) \|\| (httpGetx==0) \|\| (httpGet5 == 'w') ) {
nixnax	229:a81c37376187	902	n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed PPP-Blinky\r\n"); // 200 OK header
nixnax	142:54d1543e23e5	903	} else {
nixnax	229:a81c37376187	904	n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed PPP-Blinky\r\n"); // 404 header
nixnax	142:54d1543e23e5	905	}
nixnax	142:54d1543e23e5	906	n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax	142:54d1543e23e5	907	contentLengthStart = n; // remember where Content-Length is in buffer
nixnax	142:54d1543e23e5	908	n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax	250:35a3a19dc184	909	//n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax	217:86498f9ab967	910	#define SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	911	#ifdef SHOWMAXBUFLEVEL_YES
nixnax	209:aa514cd631ee	912	// 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	913	n=n+sprintf(n+dataStart,"Maxbuflevel: %d\r\n", ppp.rx.maxbuflevel);
nixnax	210:a2a651249a9a	914	#endif
nixnax	241:dece92cb7296	915	#define SHOWPINGCOUNT_NO
nixnax	240:d7a01533397d	916	#ifdef SHOWPINGCOUNT_YES
nixnax	241:dece92cb7296	917	// 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	918	n=n+sprintf(n+dataStart,"PingCount: %d\r\n", ppp.pingCount);
nixnax	240:d7a01533397d	919	#endif
nixnax	142:54d1543e23e5	920	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	921	nHeader=n; // size of HTTP header
nixnax	210:a2a651249a9a	922
nixnax	142:54d1543e23e5	923	if( httpGetRoot == 0 ) {
nixnax	142:54d1543e23e5	924	// this is where we insert our web page into the buffer
nixnax	142:54d1543e23e5	925	memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax	142:54d1543e23e5	926	n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax	241:dece92cb7296	927	// naximum length of pingCount (maximum number of digits of an unsigned 32-bit int)
nixnax	241:dece92cb7296	928	#define PINGCOUNTMAXLEN (10)
nixnax	241:dece92cb7296	929	char pingCountString[PINGCOUNTMAXLEN+1]; // space for the ten digits and a string terminator 0
nixnax	241:dece92cb7296	930	snprintf(pingCountString,PINGCOUNTMAXLEN+1,"%*d",PINGCOUNTMAXLEN,ppp.pingCount); // print number of ICMP pings right justified in 10 spaces
nixnax	254:7345c9a6f4c2	931	char * tenNulls = "0000000000";
nixnax	254:7345c9a6f4c2	932	char * pingCountStart = strstr(dataStart,tenNulls); // find the ten zeros in the page - this is where we must paste in the ICMP count
nixnax	241:dece92cb7296	933	if ( pingCountStart != NULL )
nixnax	241:dece92cb7296	934	memcpy(pingCountStart, pingCountString, PINGCOUNTMAXLEN); // copy ping count over the ten zeros in the page
nixnax	254:7345c9a6f4c2	935	snprintf(pingCountString,PINGCOUNTMAXLEN+1,"%*d",PINGCOUNTMAXLEN,SystemCoreClock); // print System Core Clock speed
nixnax	254:7345c9a6f4c2	936	char * coreClockStart = strstr(dataStart,tenNulls); // find the ten zeros in the page - this is where we must paste in the core clock speed
nixnax	254:7345c9a6f4c2	937	if ( coreClockStart != NULL )
nixnax	254:7345c9a6f4c2	938	memcpy(coreClockStart, pingCountString, PINGCOUNTMAXLEN); // copy core clock speed over the ten zeros in the page
nixnax	210:a2a651249a9a	939	} else if ( httpGet5 == 'w' ) { // "w" is a special page for websocket demo
nixnax	142:54d1543e23e5	940	memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax	142:54d1543e23e5	941	n = n + sizeof(webSocketPage)-1; // one less than size
nixnax	185:4cd8f91e9d49	942	*flags = TCP_FLAG_ACK \| TCP_FLAG_PSH; // for a websocket page we do NOT close the connection
nixnax	142:54d1543e23e5	943	} else {
nixnax	142:54d1543e23e5	944	if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax	142:54d1543e23e5	945	#define W3C_COMPLIANT_RESPONSE_NO
nixnax	142:54d1543e23e5	946	// change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax	142:54d1543e23e5	947	#ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax	142:54d1543e23e5	948	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax	248:5aca1c98fc24	949	#endif
nixnax	249:9ff0e20325f7	950	if( (ppp.pingCount & 1) == 0) // check lowest bit of ping counter and respond with red or green favicon - this stops browsers from asking for favicon.ico file
nixnax	249:9ff0e20325f7	951	n=n+sprintf(n+dataStart,"<link rel=\"icon\" id=\"red-pixel\" href=\"data:image/gif;base64,R0lGODlhAQABAIABAP8AAAAAACwAAAAAAQABAAACAkQBADs\">"); // data url containing 1 red pixel gif
nixnax	248:5aca1c98fc24	952	else
nixnax	249:9ff0e20325f7	953	n=n+sprintf(n+dataStart,"<link rel=\"icon\" id=\"grn-pixel\" href=\"data:image/gif;base64,R0lGODlhAQABAIABAAD/AAAAACwAAAAAAQABAAACAkQBADs=\">"); // data url containing 1 green pixel gif
nixnax	248:5aca1c98fc24	954	if( httpGet6 == 'b' ) // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax	248:5aca1c98fc24	955	n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax	248:5aca1c98fc24	956	// /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax	248:5aca1c98fc24	957	#ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax	146:a45f49a2b29c	958	n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.responseCounter); // body = the http frame count
nixnax	248:5aca1c98fc24	959	#else
nixnax	146:a45f49a2b29c	960	n=n+sprintf(n+dataStart,"%d ",ppp.responseCounter); // not really valid html but most browsers and curl are ok with it
nixnax	142:54d1543e23e5	961	#endif
nixnax	248:5aca1c98fc24	962	}
nixnax	248:5aca1c98fc24	963	else {
nixnax	249:9ff0e20325f7	964	// all other requests get a Mot Found response
nixnax	142:54d1543e23e5	965	n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax	142:54d1543e23e5	966	n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax	142:54d1543e23e5	967	}
nixnax	142:54d1543e23e5	968	}
nixnax	142:54d1543e23e5	969	#define CONTENTLENGTHSIZE 5
nixnax	142:54d1543e23e5	970	char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax	142:54d1543e23e5	971	snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax	142:54d1543e23e5	972	memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax	142:54d1543e23e5	973	return n; // total byte size of our response
nixnax	142:54d1543e23e5	974	}
nixnax	142:54d1543e23e5	975
nixnax	160:bd701ad564cb	976	/// Handle TCP data that is not an HTTP GET.
nixnax	160:bd701ad564cb	977	/// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
nixnax	160:bd701ad564cb	978	/// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax	142:54d1543e23e5	979	int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax	142:54d1543e23e5	980	{
nixnax	142:54d1543e23e5	981	int n=0; // number of bytes we have printed so far
nixnax	142:54d1543e23e5	982	if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax	160:bd701ad564cb	983	char mask [4];
nixnax	160:bd701ad564cb	984	memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax	160:bd701ad564cb	985	int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax	160:bd701ad564cb	986	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	987	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	988	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	989	memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax	160:bd701ad564cb	990	n = len; // our response size remains exactly the same length as what we received
nixnax	142:54d1543e23e5	991	} else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax	142:54d1543e23e5	992	n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax	142:54d1543e23e5	993	dataStart[1]=0; // we don't have mask bytes on
nixnax	160:bd701ad564cb	994	} else {
nixnax	184:4133f557d4d4	995	if ( len > 1 ) { // we assume a length of 1 is a keep-alive or push packet
nixnax	221:1d7c32d8256b	996	if (v1) debugPuts("TCP data received\n"); // all other tcp push packets
nixnax	184:4133f557d4d4	997	}
nixnax	163:d1b4328e9f08	998	}
nixnax	142:54d1543e23e5	999	return n; // total byte size of our response
nixnax	142:54d1543e23e5	1000	}
nixnax	142:54d1543e23e5	1001
nixnax	173:6774a0c851c4	1002	/// dump the TCP data to the debug serial port
nixnax	173:6774a0c851c4	1003	void dumpDataTCP(int outGoing)
nixnax	173:6774a0c851c4	1004	{
nixnax	173:6774a0c851c4	1005	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	173:6774a0c851c4	1006	if (v2) {
nixnax	173:6774a0c851c4	1007	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	173:6774a0c851c4	1008	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	1009	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
nixnax	173:6774a0c851c4	1010	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	173:6774a0c851c4	1011	ppp.tcpData = ppp.tcpStart + headerSizeTcp; // start of tcp data
nixnax	173:6774a0c851c4	1012	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	173:6774a0c851c4	1013	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	230:ee097c486e45	1014	char pbuf[100]; // local print buffer
nixnax	173:6774a0c851c4	1015	int n=0;
nixnax	210:a2a651249a9a	1016
nixnax	173:6774a0c851c4	1017	n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax	210:a2a651249a9a	1018
nixnax	173:6774a0c851c4	1019	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	1020	if (n>95) debugPuts("n>pbuf overflow in dumpDataTCP()\n");
nixnax	210:a2a651249a9a	1021
nixnax	221:1d7c32d8256b	1022	debugPuts( pbuf );
nixnax	173:6774a0c851c4	1023	if (tcpDataSize > 0) {
nixnax	173:6774a0c851c4	1024	ppp.tcpData[tcpDataSize]=0; // insert a null after the data so debug printf stops printing after the data
nixnax	221:1d7c32d8256b	1025	debugPuts( ppp.tcpData ); // print the tcp payload data
nixnax	221:1d7c32d8256b	1026	debugPuts("\n");
nixnax	173:6774a0c851c4	1027	}
nixnax	221:1d7c32d8256b	1028	debugPuts( "\x1b[30m" ); // VT100 color code, print black
nixnax	173:6774a0c851c4	1029	}
nixnax	173:6774a0c851c4	1030	#endif
nixnax	173:6774a0c851c4	1031	}
nixnax	173:6774a0c851c4	1032
nixnax	142:54d1543e23e5	1033	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1034	/// 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	1035	void tcpHandler()
nixnax	142:54d1543e23e5	1036	{
nixnax	154:18b2bd92f557	1037	int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
nixnax	154:18b2bd92f557	1038	int headerSizeIp = 4 * ppp.ip->headerLength; // size of ip header
nixnax	173:6774a0c851c4	1039	ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate TCP header start
nixnax	154:18b2bd92f557	1040	int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
nixnax	154:18b2bd92f557	1041	int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
nixnax	227:f87156f9ef11	1042	char * tcpDataIn = ppp.tcpStart + headerSizeTcp; // start of TCP data after TCP header
nixnax	154:18b2bd92f557	1043	int tcpDataSize = tcpSize - headerSizeTcp; // size of data block after TCP header
nixnax	154:18b2bd92f557	1044
nixnax	227:f87156f9ef11	1045	unsigned int seq_in = __REV(ppp.tcp->seqTcpR); // incoming sequence number
nixnax	227:f87156f9ef11	1046	unsigned int ack_in = __REV(ppp.tcp->ackTcpR); // incoming acknowledge number
nixnax	227:f87156f9ef11	1047	unsigned int ack_out = seq_in + tcpDataSize; // calculate the acknowledge based on size of received packet
nixnax	227:f87156f9ef11	1048	unsigned int seq_out = ack_in; // adopt their version of our sequence number as our sequence number
nixnax	142:54d1543e23e5	1049
nixnax	142:54d1543e23e5	1050	// first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax	173:6774a0c851c4	1051	headerSizeIp=20;
nixnax	173:6774a0c851c4	1052	ppp.ip->headerLength = headerSizeIp/4; // ip header is 20 bytes long
nixnax	173:6774a0c851c4	1053	ppp.ip->lengthR = __REV(40); // 20 ip header + 20 tcp header
nixnax	227:f87156f9ef11	1054	headerSizeTcp = 20; // shorten outgoing TCP header size to 20 bytes (no data)
nixnax	173:6774a0c851c4	1055	ppp.tcpStart = ppp.ipStart + headerSizeIp; // recalc TCP header start
nixnax	154:18b2bd92f557	1056	ppp.tcp->offset = (headerSizeTcp/4);
nixnax	173:6774a0c851c4	1057	char * tcpDataOut = ppp.tcpStart + headerSizeTcp; // start of outgoing data
nixnax	142:54d1543e23e5	1058
nixnax	142:54d1543e23e5	1059	int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax	142:54d1543e23e5	1060	int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax	160:bd701ad564cb	1061
nixnax	185:4cd8f91e9d49	1062	ppp.tcp->windowR = __REV16( 1200 ); // set tcp window size to 1200 bytes
nixnax	142:54d1543e23e5	1063
nixnax	142:54d1543e23e5	1064	// A sparse TCP flag interpreter that implements stateless TCP connections
nixnax	142:54d1543e23e5	1065
nixnax	156:163c23249731	1066	switch ( ppp.tcp->flag.All ) {
nixnax	142:54d1543e23e5	1067	case TCP_FLAG_SYN:
nixnax	142:54d1543e23e5	1068	flagsOut = TCP_FLAG_SYN \| TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax	142:54d1543e23e5	1069	seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax	142:54d1543e23e5	1070	ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1071	break;
nixnax	184:4133f557d4d4	1072	case TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1073	case TCP_FLAG_ACK \| TCP_FLAG_PSH:
nixnax	184:4133f557d4d4	1074	if ( (ppp.tcp->flag.All == TCP_FLAG_ACK) && (tcpDataSize == 0)) return; // handle zero-size ack messages by ignoring them
nixnax	142:54d1543e23e5	1075	if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax	237:796851817c26	1076	led1Toggle(); // toggle the LED one more time so we can visualize the HTTP GET
nixnax	179:ba2b2ddd0da5	1077	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // we have data, set the PSH flag
nixnax	185:4cd8f91e9d49	1078	dataLen = httpResponse(tcpDataOut, &flagsOut); // send an http response
nixnax	142:54d1543e23e5	1079	} else {
nixnax	158:841592aed956	1080	dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not an http GET, handle as a tcp connection
nixnax	179:ba2b2ddd0da5	1081	if (dataLen > 0) flagsOut = TCP_FLAG_ACK \| TCP_FLAG_PSH; // if we have any data set the PSH flag
nixnax	142:54d1543e23e5	1082	}
nixnax	142:54d1543e23e5	1083	break;
nixnax	142:54d1543e23e5	1084	case TCP_FLAG_FIN:
nixnax	142:54d1543e23e5	1085	case TCP_FLAG_FIN \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1086	case TCP_FLAG_FIN \| TCP_FLAG_PSH \| TCP_FLAG_ACK:
nixnax	142:54d1543e23e5	1087	flagsOut = TCP_FLAG_ACK \| TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax	142:54d1543e23e5	1088	ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax	142:54d1543e23e5	1089	break;
nixnax	142:54d1543e23e5	1090	default:
nixnax	179:ba2b2ddd0da5	1091	return; // ignore all other packets
nixnax	142:54d1543e23e5	1092	} // switch
nixnax	142:54d1543e23e5	1093
nixnax	142:54d1543e23e5	1094	// The TCP flag handling is now done
nixnax	142:54d1543e23e5	1095	// first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax	147:0f40005cbc5f	1096	swapIpAddresses(); // swap IP source and destination addresses
nixnax	149:969d98f6fb88	1097	swapIpPorts(); // swap IP source and destination ports
nixnax	142:54d1543e23e5	1098
nixnax	158:841592aed956	1099	ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	158:841592aed956	1100	ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
nixnax	160:bd701ad564cb	1101
nixnax	156:163c23249731	1102	ppp.tcp->flag.All = flagsOut; // update the TCP flags
nixnax	142:54d1543e23e5	1103
nixnax	159:4d1bf96a59cd	1104	// recalculate all the header sizes
nixnax	154:18b2bd92f557	1105	tcpSize = headerSizeTcp + dataLen; // tcp packet size
nixnax	154:18b2bd92f557	1106	int newPacketSize = headerSizeIp + tcpSize; // calculate size of the outgoing packet
nixnax	159:4d1bf96a59cd	1107	ppp.ip->lengthR = __REV16 ( newPacketSize );
nixnax	142:54d1543e23e5	1108	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	1109
nixnax	142:54d1543e23e5	1110	// the header is all set up, now do the IP and TCP checksums
nixnax	146:a45f49a2b29c	1111	IpHeaderCheckSum(); // calculate new IP header checksum
nixnax	170:3d3b2126181c	1112	checkSumPseudoHeader( tcpSize ); // get the TCP pseudo-header checksum
nixnax	159:4d1bf96a59cd	1113	ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
nixnax	161:d59f778bc8ab	1114	unsigned int pseudoHeaderSum=dataCheckSum(ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
nixnax	159:4d1bf96a59cd	1115	ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
nixnax	160:bd701ad564cb	1116
nixnax	170:3d3b2126181c	1117	dumpHeaderIP(1); // dump outgoing IP header before sending the frame
nixnax	170:3d3b2126181c	1118	dumpHeaderTCP(1); // dump outgoing TCP header before sending the frame
nixnax	173:6774a0c851c4	1119	dumpDataTCP(1); // dump outgoing TCP data before sending the frame
nixnax	226:4898247048c7	1120	#define WAIT_BEFORE_IP_SEND_NO
nixnax	226:4898247048c7	1121	#ifdef WAIT_BEFORE_IP_SEND_YES
nixnax	226:4898247048c7	1122	wait_ms(45); // 45 ms delay before sending frame
nixnax	226:4898247048c7	1123	#endif
nixnax	144:01d98cf7738e	1124	sendPppFrame(); // All preparation complete - send the TCP response
nixnax	226:4898247048c7	1125	#define DUMP_TRANSMITTED_PPP_NO
nixnax	226:4898247048c7	1126	#ifdef DUMP_TRANSMITTED_PPP_YES
nixnax	226:4898247048c7	1127	dumpPPPFrame(); // dump every transmitted ppp frame to debug port
nixnax	226:4898247048c7	1128	#endif
nixnax	142:54d1543e23e5	1129	memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax	142:54d1543e23e5	1130	}
nixnax	142:54d1543e23e5	1131
nixnax	142:54d1543e23e5	1132	/// handle an incoming TCP packet
nixnax	142:54d1543e23e5	1133	void TCPpacket()
nixnax	142:54d1543e23e5	1134	{
nixnax	173:6774a0c851c4	1135	dumpHeaderIP(0); // dump incoming packet IP header
nixnax	173:6774a0c851c4	1136	dumpHeaderTCP(0); // dump incoming packet TCP header
nixnax	173:6774a0c851c4	1137	dumpDataTCP(0); // dump incoming packet data
nixnax	142:54d1543e23e5	1138	tcpHandler();
nixnax	142:54d1543e23e5	1139	}
nixnax	142:54d1543e23e5	1140
nixnax	142:54d1543e23e5	1141	/// handle the remaining IP protocols by ignoring them
nixnax	142:54d1543e23e5	1142	void otherProtocol()
nixnax	142:54d1543e23e5	1143	{
nixnax	230:ee097c486e45	1144	debugPuts("Other IP protocol");
nixnax	142:54d1543e23e5	1145	}
nixnax	142:54d1543e23e5	1146
nixnax	142:54d1543e23e5	1147	/// process an incoming IP packet
nixnax	142:54d1543e23e5	1148	void IPframe()
nixnax	142:54d1543e23e5	1149	{
nixnax	167:ff8a2d8beeb1	1150	int protocol = ppp.ip->protocol;
nixnax	142:54d1543e23e5	1151	switch (protocol) {
nixnax	142:54d1543e23e5	1152	case 1:
nixnax	142:54d1543e23e5	1153	ICMPpacket();
nixnax	142:54d1543e23e5	1154	break;
nixnax	142:54d1543e23e5	1155	case 2:
nixnax	142:54d1543e23e5	1156	IGMPpacket();
nixnax	142:54d1543e23e5	1157	break;
nixnax	142:54d1543e23e5	1158	case 17:
nixnax	142:54d1543e23e5	1159	UDPpacket();
nixnax	142:54d1543e23e5	1160	break;
nixnax	142:54d1543e23e5	1161	case 6:
nixnax	142:54d1543e23e5	1162	TCPpacket();
nixnax	142:54d1543e23e5	1163	break;
nixnax	142:54d1543e23e5	1164	default:
nixnax	142:54d1543e23e5	1165	otherProtocol();
nixnax	142:54d1543e23e5	1166	}
nixnax	142:54d1543e23e5	1167	}
nixnax	142:54d1543e23e5	1168
nixnax	227:f87156f9ef11	1169	/// process LCP packets
nixnax	142:54d1543e23e5	1170	void LCPframe()
nixnax	142:54d1543e23e5	1171	{
nixnax	253:ee1044976b2c	1172	//ppp.pingCount++; // count how many times we get LCP packets or get pinged
nixnax	175:b4e6f8a6fe00	1173	int code = ppp.lcp->code;
nixnax	142:54d1543e23e5	1174	switch (code) {
nixnax	227:f87156f9ef11	1175	case 1: // LCP configuration request
nixnax	231:6bd4523833a2	1176	debugPuts("LCP Config");
nixnax	227:f87156f9ef11	1177	if ( __REV16( ppp.lcp->lengthR ) == 4 ) {
nixnax	230:ee097c486e45	1178	debugPuts("LCP Ack\n");
nixnax	227:f87156f9ef11	1179	ppp.lcp->code=2; // acknowledge zero configuration request
nixnax	227:f87156f9ef11	1180	sendPppFrame();
nixnax	227:f87156f9ef11	1181	ppp.lcp->code=1; // request no options
nixnax	227:f87156f9ef11	1182	sendPppFrame();
nixnax	227:f87156f9ef11	1183	} else {
nixnax	230:ee097c486e45	1184	debugPuts("LCP request reject\n");
nixnax	227:f87156f9ef11	1185	ppp.lcp->code=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax	227:f87156f9ef11	1186	sendPppFrame();
nixnax	227:f87156f9ef11	1187	}
nixnax	227:f87156f9ef11	1188	break;
nixnax	227:f87156f9ef11	1189	case 2: // LCP configuration acknowledge
nixnax	230:ee097c486e45	1190	debugPuts("LCP Ack\n"); // don't do anything, i.e. ignore
nixnax	227:f87156f9ef11	1191	break;
nixnax	227:f87156f9ef11	1192	case 5: // LCP end
nixnax	227:f87156f9ef11	1193	ppp.lcp->code=6; // acknowledge
nixnax	227:f87156f9ef11	1194	sendPppFrame(); // acknowledge
nixnax	227:f87156f9ef11	1195	ppp.online=0; // start hunting for connect string again
nixnax	227:f87156f9ef11	1196	pppInitStruct(); // flush the receive buffer
nixnax	230:ee097c486e45	1197	debugPuts("LCP End (Disconnect from host)\n");
nixnax	142:54d1543e23e5	1198	break; // end connection
nixnax	142:54d1543e23e5	1199	default:
nixnax	231:6bd4523833a2	1200	debugPuts("LCP Other\n");
nixnax	142:54d1543e23e5	1201	}
nixnax	142:54d1543e23e5	1202	}
nixnax	142:54d1543e23e5	1203
nixnax	142:54d1543e23e5	1204	/// discard packets that are not IP, IPCP, or LCP
nixnax	142:54d1543e23e5	1205	void discardedFrame()
nixnax	142:54d1543e23e5	1206	{
nixnax	142:54d1543e23e5	1207	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	1208	}
nixnax	142:54d1543e23e5	1209
nixnax	142:54d1543e23e5	1210	/// determine the packet type (IP, IPCP or LCP) of incoming packets
nixnax	142:54d1543e23e5	1211	void determinePacketType()
nixnax	142:54d1543e23e5	1212	{
nixnax	167:ff8a2d8beeb1	1213	if ( ppp.ppp->address != 0xff ) {
nixnax	231:6bd4523833a2	1214	debugPuts("Unexpected: PPP address != ff\n");
nixnax	142:54d1543e23e5	1215	return;
nixnax	142:54d1543e23e5	1216	}
nixnax	167:ff8a2d8beeb1	1217	if ( ppp.ppp->control != 3 ) {
nixnax	231:6bd4523833a2	1218	debugPuts("Unexpected: PPP control != 3\n");
nixnax	142:54d1543e23e5	1219	return;
nixnax	142:54d1543e23e5	1220	}
nixnax	167:ff8a2d8beeb1	1221	unsigned int protocol = __REV16( ppp.ppp->protocolR );
nixnax	167:ff8a2d8beeb1	1222	switch ( protocol ) {
nixnax	167:ff8a2d8beeb1	1223	case 0xc021:
nixnax	142:54d1543e23e5	1224	LCPframe();
nixnax	142:54d1543e23e5	1225	break; // link control
nixnax	167:ff8a2d8beeb1	1226	case 0x8021:
nixnax	142:54d1543e23e5	1227	IPCPframe();
nixnax	142:54d1543e23e5	1228	break; // IP control
nixnax	167:ff8a2d8beeb1	1229	case 0x0021:
nixnax	142:54d1543e23e5	1230	IPframe();
nixnax	142:54d1543e23e5	1231	break; // IP itself
nixnax	142:54d1543e23e5	1232	default:
nixnax	142:54d1543e23e5	1233	discardedFrame();
nixnax	142:54d1543e23e5	1234	}
nixnax	142:54d1543e23e5	1235	}
nixnax	142:54d1543e23e5	1236
nixnax	146:a45f49a2b29c	1237	/// a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax	146:a45f49a2b29c	1238	void sniff()
nixnax	146:a45f49a2b29c	1239	{
nixnax	221:1d7c32d8256b	1240	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	1241	}
nixnax	146:a45f49a2b29c	1242
nixnax	142:54d1543e23e5	1243	/// scan the PPP serial input stream for frame start markers
nixnax	143:c5019f856a56	1244	void waitForPppFrame()
nixnax	142:54d1543e23e5	1245	{
nixnax	142:54d1543e23e5	1246	while(1) {
nixnax	142:54d1543e23e5	1247	if ( ppp.rx.head != ppp.rx.tail ) {
nixnax	142:54d1543e23e5	1248	int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax	142:54d1543e23e5	1249	int rx = pc_getBuf(); // get the character
nixnax	238:f39289ed5a2e	1250	if (rx==0x7e) { // check for frame start/end character 0x7e
nixnax	142:54d1543e23e5	1251	if (ppp.firstFrame) { // is this the start of the first frame start
nixnax	142:54d1543e23e5	1252	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1253	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax	181:bcfe7fe2142d	1254	ppp.firstFrame=0; // clear first frame flag
nixnax	142:54d1543e23e5	1255	} else {
nixnax	142:54d1543e23e5	1256	ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax	142:54d1543e23e5	1257	processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax	142:54d1543e23e5	1258	ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax	142:54d1543e23e5	1259	ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax	142:54d1543e23e5	1260	break;
nixnax	142:54d1543e23e5	1261	}
nixnax	142:54d1543e23e5	1262	}
nixnax	142:54d1543e23e5	1263	}
nixnax	210:a2a651249a9a	1264	// change below to YES to enable the serial to UDP demo
nixnax	210:a2a651249a9a	1265	#define SERIAL_TO_UDP_NO
nixnax	210:a2a651249a9a	1266	#ifdef SERIAL_TO_UDP_YES
nixnax	210:a2a651249a9a	1267	sendUdpData(); // demo that sends characters received on the DEBUG serial port via UDP to another host
nixnax	210:a2a651249a9a	1268	#endif
nixnax	142:54d1543e23e5	1269	}
nixnax	142:54d1543e23e5	1270	}
nixnax	142:54d1543e23e5	1271
nixnax	209:aa514cd631ee	1272	/// 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	1273	// 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	1274	void waitForPcConnectString()
nixnax	142:54d1543e23e5	1275	{
nixnax	142:54d1543e23e5	1276	while(ppp.online == 0) {
nixnax	142:54d1543e23e5	1277	// search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax	142:54d1543e23e5	1278	char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax	142:54d1543e23e5	1279	if (found1 != NULL) {
nixnax	230:ee097c486e45	1280	if (v0) debugPuts("Connected: Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax	208:73086736610a	1281	// respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax	142:54d1543e23e5	1282	pc.puts("CLIENTSERVER");
nixnax	142:54d1543e23e5	1283	ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax	142:54d1543e23e5	1284	}
nixnax	142:54d1543e23e5	1285	}
nixnax	142:54d1543e23e5	1286	}
nixnax	142:54d1543e23e5	1287
nixnax	144:01d98cf7738e	1288	/// Initialize PPP data structure and set serial port(s) baud rate(s)
nixnax	144:01d98cf7738e	1289	void initializePpp()
nixnax	142:54d1543e23e5	1290	{
nixnax	210:a2a651249a9a	1291	#ifdef SERIAL_PORT_MONITOR_YES
nixnax	144:01d98cf7738e	1292	debugBaudRate(115200); // baud rate for (optional) debug serial port
nixnax	230:ee097c486e45	1293	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	1294	wait_ms(200); // a brief wait so a human can see the reset event
nixnax	230:ee097c486e45	1295	debugPuts("mbed PPP-Blinky HTTP & WebSocket server ready :)\n");
nixnax	210:a2a651249a9a	1296	#endif
nixnax	179:ba2b2ddd0da5	1297	pppInitStruct(); // initialize all the variables/properties/buffers
nixnax	179:ba2b2ddd0da5	1298	pc.baud(115200); // pc serial port acting as a dial-up modem - for PPP traffic
nixnax	179:ba2b2ddd0da5	1299	pc.attach(&pppReceiveHandler, RawSerial::RxIrq); // set up serial port receive interrupt handler
nixnax	143:c5019f856a56	1300	}

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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.