Nicolas Nackel / Mbed 2 deprecated PPP-Blinky

Small Internet Protocol Stack using a standard serial port.

Dependencies:   mbed

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.

main.cpp@130:45ee0d648a72, 2017-08-14 (annotated)

Committer:
nixnax
Date:
Mon Aug 14 04:40:02 2017 +0000
Revision:
130:45ee0d648a72
Parent:
129:b8a0b0e8cff1
Child:
131:134b6d0c11e9
Imported Sam Grove's BufferedSerial library. Eliminated all FCS errors due to dropped characters.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 93:9675adc36882 1 // PPP-Blinky - "The Most Basic Internet Of Things"
nixnax 0:2cf4880c312a 2
nixnax 128:e5958d143e9d 3 // A Tiny HTTP Webserver Using Windows XP/7/8/10/Linux Dial-Up Networking Over A Serial Port.
nixnax 41:e58a5a09f411 4 // Also receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 128:e5958d143e9d 5 // Also: WebSocket Service - see https://en.wikipedia.org/wiki/WebSocket
nixnax 4:a469050d5b80 6
nixnax 93:9675adc36882 7 // 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 81:9ede60e9a2c8 8
nixnax 41:e58a5a09f411 9 // Notes and Instructions
nixnax 41:e58a5a09f411 10 // http://bit.ly/PPP-Blinky-Instructions
nixnax 114:8a5d70bbc1b2 11 // http://bit.ly/win-rasdial-config
nixnax 0:2cf4880c312a 12
nixnax 41:e58a5a09f411 13 // Handy reading material
nixnax 6:fba4c2e817b8 14 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 15 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 39:b90183d35f1e 16 // http://bit.ly/dialup777error - how to solve Dial Up Error 777 in Windows 7/8/10
nixnax 41:e58a5a09f411 17 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 18
nixnax 29:30de79d658f6 19 // Handy tools
nixnax 44:d0c61ae49ea5 20 // https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax 109:644a59ebb5b1 21 // https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax 29:30de79d658f6 22 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 95:40af49390daf 23 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE), then custom relected-in=1, reflected-out=1
nixnax 29:30de79d658f6 24 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 41:e58a5a09f411 25 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 91:5141ae9fba53 26 // Windows Powershell invoke-webrequest command - use it to stress test the webserver like this: while (1){ invoke-webrequest -uri 172.10.10.1/x }
nixnax 41:e58a5a09f411 27
nixnax 92:cb962b365cce 28 // Connecting PPP-Blinky to Linux
nixnax 93:9675adc36882 29 // PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax 93:9675adc36882 30 // pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax 92:cb962b365cce 31 // in the above command 172.10.10.1 is the adapter IP, and 172.10.10.2 is the IP of PPP-Blinky.
nixnax 93:9675adc36882 32 // See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax 93:9675adc36882 33
nixnax 128:e5958d143e9d 34 // To try the WebSocket, enter the following in your browser console:
nixnax 128:e5958d143e9d 35 // var x = new WebSocket("ws://172.10.10.2"); x.onmessage=function(msg){console.log(msg.data);} ; x.send("Hello WebSocket World");
nixnax 128:e5958d143e9d 36
nixnax 93:9675adc36882 37 // Ok, enough talking, time to check out some code!!
nixnax 106:d14e6b597ca3 38
nixnax 81:9ede60e9a2c8 39 #include "mbed.h"
nixnax 128:e5958d143e9d 40 #include "sha1.h"
nixnax 130:45ee0d648a72 41 #include "BufferedSerial.h"
nixnax 130:45ee0d648a72 42
nixnax 93:9675adc36882 43 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax 66:f005b9fdf4d1 44 // Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor this.
nixnax 110:baec959e1915 45 // Note - the LPC11U24 does NOT have a second serial port
nixnax 127:3ea6f776e287 46 #define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax 0:2cf4880c312a 47
nixnax 93:9675adc36882 48 // here we define the OPTIONAL, second debug serial port for the various target boards
nixnax 93:9675adc36882 49 // insert your target board's port here if it's not in yet - if it works, please send it to me - thanks!!!
nixnax 129:b8a0b0e8cff1 50 // note - if you enable this, some packets may initially be missed which will cause some retransmits
nixnax 114:8a5d70bbc1b2 51 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 128:e5958d143e9d 52 #if defined(TARGET_LPC1768)
nixnax 117:c819ae068336 53 Serial 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 117:c819ae068336 54 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
nixnax 117:c819ae068336 55 Serial 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 117:c819ae068336 56 #elif defined(TARGET_LPC11U24)
nixnax 117:c819ae068336 57 #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 128:e5958d143e9d 58 #elif defined (TARGET_KL46Z) || (TARGET_KL25Z)
nixnax 128:e5958d143e9d 59 Serial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax 118:54d1936e3768 60 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 118:54d1936e3768 61 Serial xx(p9, p10); // insert your board's debug serial port pins here - and please send it to me if it works
nixnax 85:53e57ff1cf05 62 #else
nixnax 117:c819ae068336 63 #error Add your target board's second serial port here if you want to use debugging - or choose SERIAL_PORT_MONITOR_NO
nixnax 117:c819ae068336 64 #endif
nixnax 119:e14dd2bf0ea3 65 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we print debug messages */
nixnax 119:e14dd2bf0ea3 66 #define debugPutc(x...) xx.putc(x)
nixnax 118:54d1936e3768 67 #define debugBaudRate(x...) xx.baud(x)
nixnax 117:c819ae068336 68 #else
nixnax 119:e14dd2bf0ea3 69 // if we don't have a debug port the debug print functions do nothing
nixnax 119:e14dd2bf0ea3 70 #define debugPrintf(x...) {}
nixnax 119:e14dd2bf0ea3 71 #define debugPutc(x...) {}
nixnax 118:54d1936e3768 72 #define debugBaudRate(x...) {}
nixnax 41:e58a5a09f411 73 #endif
nixnax 41:e58a5a09f411 74
nixnax 110:baec959e1915 75 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 112:30172f36bd33 76 #define v0 1
nixnax 124:18ef53f1d8b7 77 #define v1 0
nixnax 77:abf92baebb42 78 #define v2 0
nixnax 114:8a5d70bbc1b2 79 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 114:8a5d70bbc1b2 80 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 29:30de79d658f6 81
nixnax 93:9675adc36882 82 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 93:9675adc36882 83 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 93:9675adc36882 84 const static char rootWebPage[] = "\
nixnax 66:f005b9fdf4d1 85 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 86 <html>\
nixnax 66:f005b9fdf4d1 87 <head>\
nixnax 128:e5958d143e9d 88 <title>mbed PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 89 <script>\
nixnax 66:f005b9fdf4d1 90 window.onload=function(){\
nixnax 66:f005b9fdf4d1 91 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 128:e5958d143e9d 92 x().textContent=parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 93 </script>\
nixnax 66:f005b9fdf4d1 94 </head>\
nixnax 66:f005b9fdf4d1 95 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 96 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 97 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 98 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 99 </body>\
nixnax 128:e5958d143e9d 100 </html>"; // around 461 bytes long
nixnax 69:23f560087c16 101
nixnax 73:2f56ec87dbe9 102 // The serial port on your mbed hardware. Your PC should be configured to view this port as a standard dial-up networking modem.
nixnax 73:2f56ec87dbe9 103 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 72:ad3d12753acf 104 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 105 // See instructions at the top.
nixnax 73:2f56ec87dbe9 106 // 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 130:45ee0d648a72 107 BufferedSerial pc(USBTX, USBRX, 500); // usb virtual com port for mbed hardware
nixnax 29:30de79d658f6 108
nixnax 29:30de79d658f6 109 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 110
nixnax 66:f005b9fdf4d1 111 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 112 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 113
nixnax 29:30de79d658f6 114 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 115 struct pppType {
nixnax 38:ab582987926e 116 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 117 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 118 int ledState; // state of LED1
nixnax 98:3babad0d1bd4 119 int httpPageCount;
nixnax 119:e14dd2bf0ea3 120 int firstFrame; // cleared after first frame
nixnax 4:a469050d5b80 121 struct {
nixnax 126:4e1058fa2128 122 #define RXBUFLEN (1<<11)
nixnax 117:c819ae068336 123 // the serial port receive buffer and packet buffer, size is RXBUFLEN (currently 2048 bytes)
nixnax 85:53e57ff1cf05 124 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in ring buffer
nixnax 93:9675adc36882 125 int head;
nixnax 93:9675adc36882 126 int tail;
nixnax 95:40af49390daf 127 int rtail;
nixnax 93:9675adc36882 128 int buflevel;
nixnax 38:ab582987926e 129 } rx; // serial port objects
nixnax 4:a469050d5b80 130 struct {
nixnax 38:ab582987926e 131 int len; // number of bytes in buffer
nixnax 38:ab582987926e 132 int crc; // PPP CRC (frame check)
nixnax 122:963abcbff21e 133 #define PPP_max_size 2500
nixnax 123:fc64fc6caae0 134 // we are assuming 1000 bytes more than MTU size of 1500 - due to the PPP encoding of special bytes
nixnax 122:963abcbff21e 135 char buf[PPP_max_size]; // send and receive buffer large enough for raw, encoded PPP/HDLC frames
nixnax 38:ab582987926e 136 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 137 struct {
nixnax 50:ad4e7c3c88e5 138 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 139 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 140 } hdlc; // hdlc frame objects
nixnax 114:8a5d70bbc1b2 141 struct {
nixnax 114:8a5d70bbc1b2 142 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 114:8a5d70bbc1b2 143 } ip; // ip related object
nixnax 29:30de79d658f6 144 };
nixnax 31:e000c1b9c565 145
nixnax 29:30de79d658f6 146 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 147
nixnax 93:9675adc36882 148 // Initialize our global structure, clear the buffer, etc.
nixnax 29:30de79d658f6 149 void pppInitStruct()
nixnax 29:30de79d658f6 150 {
nixnax 81:9ede60e9a2c8 151 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 29:30de79d658f6 152 ppp.online=0;
nixnax 29:30de79d658f6 153 ppp.rx.tail=0;
nixnax 93:9675adc36882 154 ppp.rx.rtail=0;
nixnax 29:30de79d658f6 155 ppp.rx.head=0;
nixnax 81:9ede60e9a2c8 156 ppp.rx.buflevel=0;
nixnax 29:30de79d658f6 157 ppp.pkt.len=0;
nixnax 114:8a5d70bbc1b2 158 ppp.ip.ident=10000; // easy to recognize in ip packet dumps
nixnax 29:30de79d658f6 159 ppp.ledState=0;
nixnax 81:9ede60e9a2c8 160 ppp.hdlc.frameStartIndex=0;
nixnax 98:3babad0d1bd4 161 ppp.httpPageCount=0;
nixnax 119:e14dd2bf0ea3 162 ppp.firstFrame=1;
nixnax 29:30de79d658f6 163 }
nixnax 26:11f4eb2663a7 164
nixnax 43:aa57db08995d 165 void led1Toggle()
nixnax 43:aa57db08995d 166 {
nixnax 43:aa57db08995d 167 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 93:9675adc36882 168 led1 = ppp.ledState; // toggle led
nixnax 43:aa57db08995d 169 }
nixnax 43:aa57db08995d 170
nixnax 85:53e57ff1cf05 171 // fill our own receive buffer with characters from the PPP serial port
nixnax 85:53e57ff1cf05 172 void fillbuf()
nixnax 0:2cf4880c312a 173 {
nixnax 107:5fe806713d49 174 char ch;
nixnax 85:53e57ff1cf05 175 if ( pc.readable() ) {
nixnax 85:53e57ff1cf05 176 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 93:9675adc36882 177 if ( hd == ppp.rx.rtail ) {
nixnax 119:e14dd2bf0ea3 178 debugPrintf("\nReceive buffer full\n");
nixnax 85:53e57ff1cf05 179 return;
nixnax 83:cdcb81d1910f 180 }
nixnax 107:5fe806713d49 181 ch = pc.getc(); // read new character
nixnax 107:5fe806713d49 182 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 107:5fe806713d49 183 if ( ppp.online == 0 ) {
nixnax 107:5fe806713d49 184 if (ch == 0x7E) {
nixnax 107:5fe806713d49 185 ppp.online = 1;
nixnax 114:8a5d70bbc1b2 186 }
nixnax 114:8a5d70bbc1b2 187 }
nixnax 20:5db9b77b38a6 188 ppp.rx.head = hd; // update head pointer
nixnax 81:9ede60e9a2c8 189 ppp.rx.buflevel++;
nixnax 15:b0154c910143 190 }
nixnax 0:2cf4880c312a 191 }
nixnax 0:2cf4880c312a 192
nixnax 118:54d1936e3768 193 // print to debug port while checking for incoming characters
nixnax 119:e14dd2bf0ea3 194 void putcWhileCheckingInput( char outByte )
nixnax 119:e14dd2bf0ea3 195 {
nixnax 119:e14dd2bf0ea3 196 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 119:e14dd2bf0ea3 197 fillbuf();
nixnax 119:e14dd2bf0ea3 198 debugPutc( outByte );
nixnax 119:e14dd2bf0ea3 199 fillbuf();
nixnax 119:e14dd2bf0ea3 200 #endif
nixnax 119:e14dd2bf0ea3 201 }
nixnax 119:e14dd2bf0ea3 202
nixnax 125:ea88200b1df6 203 void putsWhileCheckingInput( char * data )
nixnax 118:54d1936e3768 204 {
nixnax 118:54d1936e3768 205 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 118:54d1936e3768 206 char * nextChar = data;
nixnax 118:54d1936e3768 207 while( *nextChar != 0 ) {
nixnax 119:e14dd2bf0ea3 208 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 118:54d1936e3768 209 nextChar++;
nixnax 128:e5958d143e9d 210 }
nixnax 118:54d1936e3768 211 #endif
nixnax 118:54d1936e3768 212 }
nixnax 118:54d1936e3768 213
nixnax 124:18ef53f1d8b7 214 // a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 124:18ef53f1d8b7 215 void qq()
nixnax 124:18ef53f1d8b7 216 {
nixnax 125:ea88200b1df6 217 if ( pc.readable() ) putsWhileCheckingInput( "Character available!\n" );
nixnax 124:18ef53f1d8b7 218 }
nixnax 124:18ef53f1d8b7 219
nixnax 118:54d1936e3768 220 void crcReset()
nixnax 118:54d1936e3768 221 {
nixnax 118:54d1936e3768 222 ppp.crc=0xffff; // crc restart
nixnax 118:54d1936e3768 223 }
nixnax 118:54d1936e3768 224
nixnax 118:54d1936e3768 225 void crcDo(int x) // cumulative crc
nixnax 118:54d1936e3768 226 {
nixnax 118:54d1936e3768 227 for (int i=0; i<8; i++) {
nixnax 118:54d1936e3768 228 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 118:54d1936e3768 229 x>>=1;
nixnax 118:54d1936e3768 230 }
nixnax 124:18ef53f1d8b7 231 fillbuf(); // handle input
nixnax 118:54d1936e3768 232 }
nixnax 118:54d1936e3768 233
nixnax 118:54d1936e3768 234 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 118:54d1936e3768 235 {
nixnax 118:54d1936e3768 236 crcReset();
nixnax 118:54d1936e3768 237 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 118:54d1936e3768 238 return ppp.crc;
nixnax 118:54d1936e3768 239 }
nixnax 118:54d1936e3768 240
nixnax 85:53e57ff1cf05 241 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 242 {
nixnax 63:9253b0e1b7d8 243 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 81:9ede60e9a2c8 244 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 81:9ede60e9a2c8 245 ppp.rx.buflevel--;
nixnax 63:9253b0e1b7d8 246 return x;
nixnax 0:2cf4880c312a 247 }
nixnax 0:2cf4880c312a 248
nixnax 95:40af49390daf 249 // Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 95:40af49390daf 250 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 95:40af49390daf 251 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 95:40af49390daf 252 void dumpPPPFrame()
nixnax 95:40af49390daf 253 {
nixnax 120:bef89e4c906e 254 char pbuf[30];
nixnax 120:bef89e4c906e 255 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 124:18ef53f1d8b7 256 fillbuf();
nixnax 124:18ef53f1d8b7 257 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 124:18ef53f1d8b7 258 fillbuf();
nixnax 125:ea88200b1df6 259 putsWhileCheckingInput(pbuf);
nixnax 124:18ef53f1d8b7 260 }
nixnax 124:18ef53f1d8b7 261 fillbuf();
nixnax 124:18ef53f1d8b7 262 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 124:18ef53f1d8b7 263 fillbuf();
nixnax 125:ea88200b1df6 264 putsWhileCheckingInput(pbuf);
nixnax 95:40af49390daf 265 }
nixnax 95:40af49390daf 266
nixnax 119:e14dd2bf0ea3 267 void processPPPFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 268 {
nixnax 38:ab582987926e 269 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 270 if(start==end) {
nixnax 111:6a3b77c065c0 271 return; // empty frame
nixnax 29:30de79d658f6 272 }
nixnax 9:0992486d4a30 273 crcReset();
nixnax 9:0992486d4a30 274 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 275 ppp.pkt.len=0;
nixnax 9:0992486d4a30 276 int unstuff=0;
nixnax 17:4918c893d802 277 int idx = start;
nixnax 17:4918c893d802 278 while(1) {
nixnax 124:18ef53f1d8b7 279 fillbuf();
nixnax 9:0992486d4a30 280 if (unstuff==0) {
nixnax 72:ad3d12753acf 281 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 282 else {
nixnax 72:ad3d12753acf 283 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 284 ppp.pkt.len++;
nixnax 29:30de79d658f6 285 dest++;
nixnax 72:ad3d12753acf 286 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 287 }
nixnax 66:f005b9fdf4d1 288 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 289 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 290 ppp.pkt.len++;
nixnax 29:30de79d658f6 291 dest++;
nixnax 72:ad3d12753acf 292 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 293 unstuff=0;
nixnax 9:0992486d4a30 294 }
nixnax 81:9ede60e9a2c8 295 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 296 if (idx == end) break;
nixnax 9:0992486d4a30 297 }
nixnax 29:30de79d658f6 298 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 120:bef89e4c906e 299 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 9:0992486d4a30 300 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 301 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 302 determinePacketType();
nixnax 90:55e0f243a7ce 303 } else {
nixnax 130:45ee0d648a72 304 #define REPORT_FCS_ERROR_YES
nixnax 128:e5958d143e9d 305 #ifdef REPORT_FCS_ERROR_YES
nixnax 128:e5958d143e9d 306 char pbuf[50]; // local print buffer
nixnax 128:e5958d143e9d 307 fillbuf();
nixnax 128:e5958d143e9d 308 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 128:e5958d143e9d 309 fillbuf();
nixnax 128:e5958d143e9d 310 putsWhileCheckingInput( pbuf );
nixnax 128:e5958d143e9d 311 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 128:e5958d143e9d 312 #endif
nixnax 9:0992486d4a30 313 }
nixnax 9:0992486d4a30 314 }
nixnax 9:0992486d4a30 315
nixnax 124:18ef53f1d8b7 316 void pcPutcWhileCheckingInput(int ch)
nixnax 124:18ef53f1d8b7 317 {
nixnax 124:18ef53f1d8b7 318 fillbuf(); // check input
nixnax 124:18ef53f1d8b7 319 pc.putc(ch);
nixnax 124:18ef53f1d8b7 320 fillbuf();
nixnax 124:18ef53f1d8b7 321 }
nixnax 124:18ef53f1d8b7 322
nixnax 29:30de79d658f6 323 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 324 {
nixnax 29:30de79d658f6 325 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 124:18ef53f1d8b7 326 pcPutcWhileCheckingInput(0x7d);
nixnax 124:18ef53f1d8b7 327 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 328 } else {
nixnax 124:18ef53f1d8b7 329 pcPutcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 330 }
nixnax 11:f58998c24f0b 331 }
nixnax 9:0992486d4a30 332
nixnax 93:9675adc36882 333 void send_pppFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 334 {
nixnax 17:4918c893d802 335 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 336 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 337 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 124:18ef53f1d8b7 338 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 95:40af49390daf 339 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 93:9675adc36882 340 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 93:9675adc36882 341 }
nixnax 124:18ef53f1d8b7 342 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 343 }
nixnax 9:0992486d4a30 344
nixnax 93:9675adc36882 345 void ipcpConfigRequestHandler()
nixnax 29:30de79d658f6 346 {
nixnax 119:e14dd2bf0ea3 347 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 92:cb962b365cce 348 ppp.pkt.buf[4]=2; // change code to ack
nixnax 108:f77ec4605945 349 send_pppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 106:d14e6b597ca3 350
nixnax 119:e14dd2bf0ea3 351 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 92:cb962b365cce 352 ppp.pkt.buf[4]=1; // change code to request
nixnax 106:d14e6b597ca3 353 ppp.pkt.buf[7]=4; // no options in this request
nixnax 106:d14e6b597ca3 354 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 128:e5958d143e9d 355 send_pppFrame(); // send our request
nixnax 9:0992486d4a30 356 }
nixnax 9:0992486d4a30 357
nixnax 93:9675adc36882 358 void ipcpAckHandler()
nixnax 29:30de79d658f6 359 {
nixnax 119:e14dd2bf0ea3 360 debugPrintf("Their IPCP Grant\n");
nixnax 29:30de79d658f6 361 }
nixnax 9:0992486d4a30 362
nixnax 93:9675adc36882 363 void ipcpNackHandler()
nixnax 29:30de79d658f6 364 {
nixnax 119:e14dd2bf0ea3 365 debugPrintf("Their IPCP Nack, Our ACK\n");
nixnax 107:5fe806713d49 366 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 106:d14e6b597ca3 367 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 106:d14e6b597ca3 368 send_pppFrame(); // let's request this IP address as ours
nixnax 106:d14e6b597ca3 369 } // if it's not an IP nack we ignore it
nixnax 29:30de79d658f6 370 }
nixnax 9:0992486d4a30 371
nixnax 93:9675adc36882 372 void ipcpDefaultHandler()
nixnax 29:30de79d658f6 373 {
nixnax 119:e14dd2bf0ea3 374 debugPrintf("Their IPCP Other\n");
nixnax 29:30de79d658f6 375 }
nixnax 29:30de79d658f6 376
nixnax 29:30de79d658f6 377 void IPCPframe()
nixnax 29:30de79d658f6 378 {
nixnax 9:0992486d4a30 379 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 380 switch (code) {
nixnax 29:30de79d658f6 381 case 1:
nixnax 93:9675adc36882 382 ipcpConfigRequestHandler();
nixnax 29:30de79d658f6 383 break;
nixnax 29:30de79d658f6 384 case 2:
nixnax 93:9675adc36882 385 ipcpAckHandler();
nixnax 29:30de79d658f6 386 break;
nixnax 29:30de79d658f6 387 case 3:
nixnax 93:9675adc36882 388 ipcpNackHandler();
nixnax 29:30de79d658f6 389 break;
nixnax 29:30de79d658f6 390 default:
nixnax 93:9675adc36882 391 ipcpDefaultHandler();
nixnax 9:0992486d4a30 392 }
nixnax 29:30de79d658f6 393 }
nixnax 9:0992486d4a30 394
nixnax 29:30de79d658f6 395 void UDPpacket()
nixnax 29:30de79d658f6 396 {
nixnax 12:db0dc91f0231 397 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 398 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 399 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 118:54d1936e3768 400 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 401 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 402 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 403 #endif
nixnax 12:db0dc91f0231 404 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 405 char * udpInf = udpBlock+8; // actual start of info
nixnax 118:54d1936e3768 406 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 407 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 408 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 409 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 410 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 411 #endif
nixnax 29:30de79d658f6 412 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 413 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 119:e14dd2bf0ea3 414 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 119:e14dd2bf0ea3 415 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 119:e14dd2bf0ea3 416 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 29:30de79d658f6 417 int printSize = udpLength;
nixnax 29:30de79d658f6 418 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 419 if (v1) {
nixnax 29:30de79d658f6 420 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 421 char ch = udpInf[i];
nixnax 29:30de79d658f6 422 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 423 debugPrintf("%c", ch);
nixnax 29:30de79d658f6 424 } else {
nixnax 119:e14dd2bf0ea3 425 debugPrintf("_");
nixnax 29:30de79d658f6 426 }
nixnax 29:30de79d658f6 427 }
nixnax 29:30de79d658f6 428 }
nixnax 119:e14dd2bf0ea3 429 if (v0) debugPrintf("\n");
nixnax 12:db0dc91f0231 430 }
nixnax 11:f58998c24f0b 431
nixnax 76:00e208cceb8b 432 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 433 {
nixnax 128:e5958d143e9d 434 unsigned int i,hi,lo,sum;
nixnax 76:00e208cceb8b 435 unsigned char placeHolder;
nixnax 29:30de79d658f6 436 if (len&1) {
nixnax 128:e5958d143e9d 437 placeHolder = ptr[len];
nixnax 128:e5958d143e9d 438 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 29:30de79d658f6 439 }
nixnax 128:e5958d143e9d 440 sum=0;
nixnax 128:e5958d143e9d 441 i=0;
nixnax 128:e5958d143e9d 442 while ( i<len ) {
nixnax 124:18ef53f1d8b7 443 fillbuf();
nixnax 128:e5958d143e9d 444 hi = ptr[i++];
nixnax 128:e5958d143e9d 445 lo = ptr[i++];
nixnax 128:e5958d143e9d 446 sum = sum + ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 447 }
nixnax 29:30de79d658f6 448 if (len&1) {
nixnax 128:e5958d143e9d 449 ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax 29:30de79d658f6 450 }
nixnax 76:00e208cceb8b 451 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 452 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 453 return ~sum;
nixnax 29:30de79d658f6 454 }
nixnax 11:f58998c24f0b 455
nixnax 29:30de79d658f6 456 void headerCheckSum()
nixnax 29:30de79d658f6 457 {
nixnax 11:f58998c24f0b 458 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 459 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 460 int sum=0;
nixnax 11:f58998c24f0b 461
nixnax 29:30de79d658f6 462 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 463 int hi = *ptr;
nixnax 29:30de79d658f6 464 ptr++;
nixnax 29:30de79d658f6 465 int lo = *ptr;
nixnax 29:30de79d658f6 466 ptr++;
nixnax 11:f58998c24f0b 467 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 468 sum = sum + val;
nixnax 124:18ef53f1d8b7 469 fillbuf();
nixnax 11:f58998c24f0b 470 }
nixnax 11:f58998c24f0b 471 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 472 sum = ~sum;
nixnax 11:f58998c24f0b 473 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 474 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 475 }
nixnax 9:0992486d4a30 476
nixnax 29:30de79d658f6 477 void ICMPpacket() // internet control message protocol
nixnax 128:e5958d143e9d 478 {
nixnax 12:db0dc91f0231 479 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 480 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 481 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 482 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 483 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 484 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 485 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 486 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 487 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 488 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 489 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 490 char * dstAdr = ipPkt+16;
nixnax 124:18ef53f1d8b7 491 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 18:3e35de1bc877 492 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 493 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 125:ea88200b1df6 494 if(1) {
nixnax 124:18ef53f1d8b7 495 char pbuf[50];
nixnax 124:18ef53f1d8b7 496 fillbuf();
nixnax 124:18ef53f1d8b7 497 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 125:ea88200b1df6 498 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 499 fillbuf();
nixnax 125:ea88200b1df6 500 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 124:18ef53f1d8b7 501 fillbuf();
nixnax 125:ea88200b1df6 502 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 503 }
nixnax 128:e5958d143e9d 504 #endif
nixnax 29:30de79d658f6 505 char src[4];
nixnax 29:30de79d658f6 506 char dst[4];
nixnax 12:db0dc91f0231 507 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 508 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 509 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 510 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 511 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 512 chkSum[0]=0;
nixnax 29:30de79d658f6 513 chkSum[1]=0;
nixnax 12:db0dc91f0231 514 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 515 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 516 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 517 icmpSum[0]=0;
nixnax 29:30de79d658f6 518 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 519 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 520 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 521 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 522 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 523
nixnax 16:cb0b80c24ba2 524 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 525 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 526 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 124:18ef53f1d8b7 527 if (0) {
nixnax 29:30de79d658f6 528 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 529 char ch = icmpData[i];
nixnax 29:30de79d658f6 530 if (ch>31 && ch<127) {
nixnax 124:18ef53f1d8b7 531 putcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 532 } else {
nixnax 124:18ef53f1d8b7 533 putcWhileCheckingInput('_');
nixnax 29:30de79d658f6 534 }
nixnax 29:30de79d658f6 535 }
nixnax 124:18ef53f1d8b7 536 putcWhileCheckingInput('\n');
nixnax 29:30de79d658f6 537 }
nixnax 93:9675adc36882 538 send_pppFrame(); // reply to the ping
nixnax 12:db0dc91f0231 539 } else {
nixnax 29:30de79d658f6 540 if (v0) {
nixnax 119:e14dd2bf0ea3 541 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 542 }
nixnax 128:e5958d143e9d 543 }
nixnax 11:f58998c24f0b 544 }
nixnax 11:f58998c24f0b 545
nixnax 29:30de79d658f6 546 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 547 {
nixnax 119:e14dd2bf0ea3 548 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 549 }
nixnax 11:f58998c24f0b 550
nixnax 114:8a5d70bbc1b2 551 void dumpHeaderIP (int outGoing)
nixnax 29:30de79d658f6 552 {
nixnax 114:8a5d70bbc1b2 553 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 119:e14dd2bf0ea3 554 fillbuf(); // we are expecting the first character of the next packet
nixnax 114:8a5d70bbc1b2 555 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 114:8a5d70bbc1b2 556 char * ident = ipPkt+4; // 2 bytes
nixnax 118:54d1936e3768 557 #ifdef UNUSED_IP_VARIABLES
nixnax 114:8a5d70bbc1b2 558 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 114:8a5d70bbc1b2 559 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 114:8a5d70bbc1b2 560 char * version = ipPkt; // top 4 bits
nixnax 114:8a5d70bbc1b2 561 char * ihl = ipPkt; // bottom 4 bits
nixnax 114:8a5d70bbc1b2 562 char * dscp = ipPkt+1; // top 6 bits
nixnax 114:8a5d70bbc1b2 563 char * ecn = ipPkt+1; // lower 2 bits
nixnax 114:8a5d70bbc1b2 564 char * pktLen = ipPkt+2; // 2 bytes
nixnax 114:8a5d70bbc1b2 565 char * flags = ipPkt+6; // 2 bits
nixnax 114:8a5d70bbc1b2 566 char * ttl = ipPkt+8; // 1 byte
nixnax 114:8a5d70bbc1b2 567 char * protocol = ipPkt+9; // 1 byte
nixnax 114:8a5d70bbc1b2 568 char * headercheck= ipPkt+10; // 2 bytes
nixnax 114:8a5d70bbc1b2 569 int versionIP = (version[0]>>4)&0xf;
nixnax 114:8a5d70bbc1b2 570 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 114:8a5d70bbc1b2 571 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 114:8a5d70bbc1b2 572 int ecnIP = ecn[0]&3;
nixnax 114:8a5d70bbc1b2 573 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 114:8a5d70bbc1b2 574 int flagsIP = flags[0]>>14&3;
nixnax 114:8a5d70bbc1b2 575 int ttlIP = ttl[0];
nixnax 114:8a5d70bbc1b2 576 int protocolIP = protocol[0];
nixnax 114:8a5d70bbc1b2 577 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 578 #endif
nixnax 119:e14dd2bf0ea3 579 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 119:e14dd2bf0ea3 580 char pbuf[50]; // local print buffer
nixnax 118:54d1936e3768 581 int n=0;
nixnax 119:e14dd2bf0ea3 582 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 119:e14dd2bf0ea3 583 n=n+sprintf(pbuf+n, "%05d ",IPv4Id); // IPv4Id is a good way to correlate our dumps with net monitor or wireshark traces
nixnax 119:e14dd2bf0ea3 584 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 585 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 586 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 119:e14dd2bf0ea3 587 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 119:e14dd2bf0ea3 588 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 55:43faae812be3 589 #endif
nixnax 125:ea88200b1df6 590 putsWhileCheckingInput( pbuf );
nixnax 114:8a5d70bbc1b2 591 #ifndef TCP_HEADER_DUMP_YES
nixnax 125:ea88200b1df6 592 putsWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 114:8a5d70bbc1b2 593 #endif
nixnax 114:8a5d70bbc1b2 594 #endif
nixnax 29:30de79d658f6 595 }
nixnax 26:11f4eb2663a7 596
nixnax 114:8a5d70bbc1b2 597 void dumpHeaderTCP(int outGoing)
nixnax 29:30de79d658f6 598 {
nixnax 114:8a5d70bbc1b2 599 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 114:8a5d70bbc1b2 600 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 114:8a5d70bbc1b2 601 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 114:8a5d70bbc1b2 602 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 114:8a5d70bbc1b2 603 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 114:8a5d70bbc1b2 604 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 114:8a5d70bbc1b2 605 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 114:8a5d70bbc1b2 606 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 114:8a5d70bbc1b2 607 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 114:8a5d70bbc1b2 608 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 119:e14dd2bf0ea3 609 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 119:e14dd2bf0ea3 610 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 119:e14dd2bf0ea3 611 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 114:8a5d70bbc1b2 612 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 114:8a5d70bbc1b2 613 flagInfo[8]=0; // null terminate string
nixnax 114:8a5d70bbc1b2 614 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 114:8a5d70bbc1b2 615 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 114:8a5d70bbc1b2 616 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 114:8a5d70bbc1b2 617 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 114:8a5d70bbc1b2 618 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 114:8a5d70bbc1b2 619 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 114:8a5d70bbc1b2 620 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 114:8a5d70bbc1b2 621 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 118:54d1936e3768 622 #else
nixnax 119:e14dd2bf0ea3 623 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 119:e14dd2bf0ea3 624 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 119:e14dd2bf0ea3 625 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 119:e14dd2bf0ea3 626 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 119:e14dd2bf0ea3 627 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 124:18ef53f1d8b7 628 flagInfo[1]=0; // ' '
nixnax 119:e14dd2bf0ea3 629 flagInfo[2]=0;
nixnax 118:54d1936e3768 630 #endif
nixnax 125:ea88200b1df6 631 putsWhileCheckingInput( flagInfo );
nixnax 119:e14dd2bf0ea3 632 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 633 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 125:ea88200b1df6 634 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 119:e14dd2bf0ea3 635 #endif
nixnax 119:e14dd2bf0ea3 636 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 119:e14dd2bf0ea3 637 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 118:54d1936e3768 638 }
nixnax 114:8a5d70bbc1b2 639 #endif
nixnax 29:30de79d658f6 640 }
nixnax 29:30de79d658f6 641
nixnax 128:e5958d143e9d 642 void enc64(char * in, char * out, int len)
nixnax 128:e5958d143e9d 643 {
nixnax 128:e5958d143e9d 644 const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax 128:e5958d143e9d 645 int i,j,a,b,c;
nixnax 128:e5958d143e9d 646 i=0;
nixnax 128:e5958d143e9d 647 j=0;
nixnax 128:e5958d143e9d 648 while(1) {
nixnax 128:e5958d143e9d 649 if (i<len) {
nixnax 128:e5958d143e9d 650 a = in[i++];
nixnax 128:e5958d143e9d 651 out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax 128:e5958d143e9d 652 } else break;
nixnax 128:e5958d143e9d 653 if (i<len) {
nixnax 128:e5958d143e9d 654 b = in[i++];
nixnax 128:e5958d143e9d 655 out[j++] = lut[ ( (a << 4) & 0x30) | ( (b >> 4) & 0x0f) ];
nixnax 128:e5958d143e9d 656 out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax 128:e5958d143e9d 657 } else out[j++] = '=';
nixnax 128:e5958d143e9d 658 if (i<len) {
nixnax 128:e5958d143e9d 659 c = in[i++];
nixnax 128:e5958d143e9d 660 j--;
nixnax 128:e5958d143e9d 661 out[j++] = lut[ ( (b << 2) & 0x3c) | ( (c >> 6) & 0x03) ];
nixnax 128:e5958d143e9d 662 out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax 128:e5958d143e9d 663 } else out[j++] = '=';
nixnax 128:e5958d143e9d 664 }
nixnax 128:e5958d143e9d 665 out[j]=0;
nixnax 128:e5958d143e9d 666 }
nixnax 128:e5958d143e9d 667
nixnax 128:e5958d143e9d 668 // we end up here if we enter the following javascript in a web browser console: x = new WebSocket("ws://172.10.10.2");
nixnax 128:e5958d143e9d 669 int webSocketHandler(char * dataStart)
nixnax 128:e5958d143e9d 670 {
nixnax 128:e5958d143e9d 671 int n=0; // byte counter
nixnax 128:e5958d143e9d 672 char * key = strstr(dataStart, "Sec-WebSocket-Key: "); // search for the key in the payload
nixnax 128:e5958d143e9d 673 if (key != NULL) {
nixnax 129:b8a0b0e8cff1 674 if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax 128:e5958d143e9d 675 char challenge [70];
nixnax 128:e5958d143e9d 676 strncpy(challenge,key+19,70); // a local buffer
nixnax 128:e5958d143e9d 677 *strchr(challenge,'\r')=0; // insert null so we can use sprintf
nixnax 128:e5958d143e9d 678 strncat(challenge,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11",70); // append websocket gui code
nixnax 128:e5958d143e9d 679 char shaOutput [20]; // sha1 output
nixnax 128:e5958d143e9d 680 sha1( shaOutput, challenge, strlen(challenge));
nixnax 128:e5958d143e9d 681 char encOut[50];
nixnax 128:e5958d143e9d 682 enc64( shaOutput, encOut, 20);
nixnax 128:e5958d143e9d 683 char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax 128:e5958d143e9d 684 char * version = challenge;
nixnax 128:e5958d143e9d 685 strncpy(version, versionstring,70); // copy version string
nixnax 128:e5958d143e9d 686 *strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax 128:e5958d143e9d 687 memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax 128:e5958d143e9d 688 n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax 128:e5958d143e9d 689 n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax 128:e5958d143e9d 690 n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax 128:e5958d143e9d 691 n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax 128:e5958d143e9d 692 n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax 128:e5958d143e9d 693 n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax 128:e5958d143e9d 694 n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax 128:e5958d143e9d 695 }
nixnax 128:e5958d143e9d 696 return n; // this response should satisfy a web browser's websocket protocol request
nixnax 128:e5958d143e9d 697 }
nixnax 128:e5958d143e9d 698
nixnax 128:e5958d143e9d 699 #define TCP_FLAG_ACK (1<<4)
nixnax 128:e5958d143e9d 700 #define TCP_FLAG_SYN (1<<1)
nixnax 128:e5958d143e9d 701 #define TCP_FLAG_PSH (1<<3)
nixnax 128:e5958d143e9d 702 #define TCP_FLAG_RST (1<<2)
nixnax 128:e5958d143e9d 703 #define TCP_FLAG_FIN (1<<0)
nixnax 128:e5958d143e9d 704
nixnax 68:0b74763ae67f 705 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 706 {
nixnax 67:a63e3486bcda 707 int n=0; // number of bytes we have printed so far
nixnax 128:e5958d143e9d 708 n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax 128:e5958d143e9d 709 if (n>0) return n; // if it's a WebSocket we already have the response, so return
nixnax 128:e5958d143e9d 710
nixnax 77:abf92baebb42 711 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 712 int contentLengthStart; // index where HTML starts
nixnax 128:e5958d143e9d 713 int httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax 85:53e57ff1cf05 714
nixnax 98:3babad0d1bd4 715 ppp.httpPageCount++; // increment the number of frames we have made
nixnax 85:53e57ff1cf05 716
nixnax 128:e5958d143e9d 717 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax 128:e5958d143e9d 718 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 119:e14dd2bf0ea3 719 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 128:e5958d143e9d 720 if( (httpGetRoot==0) || (httpGetx==0) ) {
nixnax 115:b8ddff0e782f 721 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky\r\n"); // 200 OK header
nixnax 83:cdcb81d1910f 722 } else {
nixnax 89:2c8dd0c2a426 723 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 83:cdcb81d1910f 724 }
nixnax 83:cdcb81d1910f 725 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 726 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 727 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 728 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 729 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 83:cdcb81d1910f 730 nHeader=n; // size of HTTP header
nixnax 93:9675adc36882 731 if( httpGetRoot == 0 ) {
nixnax 83:cdcb81d1910f 732 // this is where we insert our web page into the buffer
nixnax 93:9675adc36882 733 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 93:9675adc36882 734 n = n + sizeof(rootWebPage);
nixnax 85:53e57ff1cf05 735 } else {
nixnax 128:e5958d143e9d 736 if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax 89:2c8dd0c2a426 737
nixnax 89:2c8dd0c2a426 738 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 89:2c8dd0c2a426 739 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 89:2c8dd0c2a426 740 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 128:e5958d143e9d 741 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax 98:3babad0d1bd4 742 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.httpPageCount); // body = the http frame count
nixnax 89:2c8dd0c2a426 743 #else
nixnax 109:644a59ebb5b1 744 #define BENCHMARK_USING_BROWSER_NO /* set to _YES if you want to use your browser as a benchmark tool */
nixnax 98:3babad0d1bd4 745 #ifndef BENCHMARK_USING_BROWSER_NO
nixnax 119:e14dd2bf0ea3 746 // semd a small browser script that will reload the page after 10 ms - handy for benchmarking with your web browser, use http://172.10.10.2/x
nixnax 98:3babad0d1bd4 747 n=n+sprintf(n+dataStart, "<script>setTimeout(function(){location.reload();},10);</script><body>%d</body>",ppp.httpPageCount);
nixnax 98:3babad0d1bd4 748 #else
nixnax 128:e5958d143e9d 749 // /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax 129:b8a0b0e8cff1 750 n=n+sprintf(n+dataStart,"%d ",ppp.httpPageCount); // not really valid html but fast - most browsers and curl are ok with it
nixnax 98:3babad0d1bd4 751 #endif
nixnax 89:2c8dd0c2a426 752 #endif
nixnax 89:2c8dd0c2a426 753 } else {
nixnax 89:2c8dd0c2a426 754 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 128:e5958d143e9d 755 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax 89:2c8dd0c2a426 756 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 89:2c8dd0c2a426 757 }
nixnax 83:cdcb81d1910f 758 }
nixnax 83:cdcb81d1910f 759 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 760 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 761 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 762 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 763 return n; // total byte size of our response
nixnax 67:a63e3486bcda 764 }
nixnax 67:a63e3486bcda 765
nixnax 128:e5958d143e9d 766 // this is the response if we have TCP data but it's not an HTTP GET
nixnax 98:3babad0d1bd4 767 // this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 128:e5958d143e9d 768 // this could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax 128:e5958d143e9d 769 int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax 98:3babad0d1bd4 770 {
nixnax 98:3babad0d1bd4 771 int n=0; // number of bytes we have printed so far
nixnax 128:e5958d143e9d 772 if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax 128:e5958d143e9d 773 // this is most likely a websocket push message. you get this when you enter this in your browser console: x.send("my message");
nixnax 128:e5958d143e9d 774 if (0) putsWhileCheckingInput( "Got data from websocket send()\n" );
nixnax 128:e5958d143e9d 775
nixnax 128:e5958d143e9d 776 // for now we simply echo the websocket data back to the client - the client should therefore see an onmessage event
nixnax 128:e5958d143e9d 777 // to display the echoed data in your browser, enter the following into the browser console: x.onmessage = function(msg){ console.log( msg.data ); }
nixnax 128:e5958d143e9d 778 if (1) {
nixnax 128:e5958d143e9d 779 char mask [4];
nixnax 128:e5958d143e9d 780 memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax 128:e5958d143e9d 781 int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax 128:e5958d143e9d 782 if((dataStart[1]&0x80)==0x80) // test if the mask bit is set, which means all data is xor'ed with the mask
nixnax 128:e5958d143e9d 783 for (int i=0; i<websocketMessageSize; i++) dataStart[i+6]^= mask[i%4]; // unmask each byte with one of the mask bytes
nixnax 128:e5958d143e9d 784 dataStart[1] = len-2; // add four extra bytes to the message length because we don't use mask bytes for the send
nixnax 128:e5958d143e9d 785 memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax 128:e5958d143e9d 786 n = len; // our response size remains exactly the same length as what we received
nixnax 128:e5958d143e9d 787 }
nixnax 128:e5958d143e9d 788 } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax 128:e5958d143e9d 789 *outFlags |= TCP_FLAG_FIN; // set the fin flag to close the websocket request
nixnax 128:e5958d143e9d 790 } else if (v1) putsWhileCheckingInput("TCP data received\n");
nixnax 98:3babad0d1bd4 791 return n; // total byte size of our response
nixnax 98:3babad0d1bd4 792 }
nixnax 98:3babad0d1bd4 793
nixnax 29:30de79d658f6 794 void tcpHandler()
nixnax 29:30de79d658f6 795 {
nixnax 87:9f5ac1fabd95 796 // IP header
nixnax 26:11f4eb2663a7 797 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 798 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 799 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 800 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 801 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 802 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 803 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 804 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 805 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 806 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 807
nixnax 87:9f5ac1fabd95 808 // TCP header
nixnax 87:9f5ac1fabd95 809 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 87:9f5ac1fabd95 810 char * srctcp = tcp + 0; // 2 bytes
nixnax 87:9f5ac1fabd95 811 char * dsttcp = tcp + 2; // 2 bytes
nixnax 87:9f5ac1fabd95 812 char * seqtcp = tcp + 4; // 4 bytes
nixnax 87:9f5ac1fabd95 813 char * acktcp = tcp + 8; // 4 bytes
nixnax 87:9f5ac1fabd95 814 char * offset = tcp + 12; // 4 bits
nixnax 87:9f5ac1fabd95 815 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 87:9f5ac1fabd95 816 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 87:9f5ac1fabd95 817 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 128:e5958d143e9d 818
nixnax 124:18ef53f1d8b7 819 if(ident) {}; // shut up unused variable reference warning
nixnax 26:11f4eb2663a7 820 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 821 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 822 int protocolIP = protocol[0];
nixnax 87:9f5ac1fabd95 823 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 824 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 87:9f5ac1fabd95 825 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 85:53e57ff1cf05 826 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 85:53e57ff1cf05 827 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 85:53e57ff1cf05 828 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 87:9f5ac1fabd95 829 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 81:9ede60e9a2c8 830
nixnax 128:e5958d143e9d 831 // first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax 87:9f5ac1fabd95 832 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 87:9f5ac1fabd95 833 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 87:9f5ac1fabd95 834 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 87:9f5ac1fabd95 835 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 836 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 837 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 838
nixnax 35:e7068df4d971 839 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 840 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 87:9f5ac1fabd95 841 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 119:e14dd2bf0ea3 842 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 119:e14dd2bf0ea3 843 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 38:ab582987926e 844
nixnax 106:d14e6b597ca3 845 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 77:abf92baebb42 846
nixnax 69:23f560087c16 847 switch ( flagsTCP ) {
nixnax 128:e5958d143e9d 848 case TCP_FLAG_ACK:
nixnax 128:e5958d143e9d 849 return;
nixnax 69:23f560087c16 850 case TCP_FLAG_SYN:
nixnax 87:9f5ac1fabd95 851 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 119:e14dd2bf0ea3 852 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 85:53e57ff1cf05 853 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 854 break;
nixnax 77:abf92baebb42 855 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 128:e5958d143e9d 856 if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax 128:e5958d143e9d 857 flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // set outgoing FIN flag to ask them to close from their side
nixnax 87:9f5ac1fabd95 858 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 98:3babad0d1bd4 859 } else {
nixnax 128:e5958d143e9d 860 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not a web request, send a packet reporting number of received bytes
nixnax 69:23f560087c16 861 }
nixnax 69:23f560087c16 862 break;
nixnax 116:1272e9f7ad70 863 case TCP_FLAG_FIN:
nixnax 116:1272e9f7ad70 864 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 98:3babad0d1bd4 865 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 117:c819ae068336 866 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 128:e5958d143e9d 867 ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 868 break;
nixnax 77:abf92baebb42 869 default:
nixnax 69:23f560087c16 870 return; // ignore remaining packets
nixnax 93:9675adc36882 871 } // switch
nixnax 77:abf92baebb42 872
nixnax 69:23f560087c16 873 // The TCP flag handling is now done
nixnax 105:45001195b325 874 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 65:23b17c43aa0f 875 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 876 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 877 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 878 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 879 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 880 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 881 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 95:40af49390daf 882
nixnax 85:53e57ff1cf05 883 acktcp[0]=ack_out>>24;
nixnax 85:53e57ff1cf05 884 acktcp[1]=ack_out>>16;
nixnax 85:53e57ff1cf05 885 acktcp[2]=ack_out>>8;
nixnax 85:53e57ff1cf05 886 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 85:53e57ff1cf05 887 seqtcp[0]=seq_out>>24;
nixnax 85:53e57ff1cf05 888 seqtcp[1]=seq_out>>16;
nixnax 85:53e57ff1cf05 889 seqtcp[2]=seq_out>>8;
nixnax 85:53e57ff1cf05 890 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 891
nixnax 93:9675adc36882 892 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 93:9675adc36882 893
nixnax 114:8a5d70bbc1b2 894 // increment our outgoing ip packet counter
nixnax 114:8a5d70bbc1b2 895 ppp.ip.ident++; // get next ident number for our packet
nixnax 93:9675adc36882 896
nixnax 106:d14e6b597ca3 897 // Now we recalculate all the header sizes
nixnax 38:ab582987926e 898 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 899 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 900 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 901 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 902 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 903
nixnax 38:ab582987926e 904 // the header is all set up, now do the IP and TCP checksums
nixnax 61:b3c1a04efd0a 905 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 906 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 907 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 908
nixnax 64:677b9713a120 909 // now we have to build the so-called 12-byte TCP "pseudo-header" in front of the TCP header (containing some IP header values) in order to correctly calculate the TCP checksum
nixnax 63:9253b0e1b7d8 910 // this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax 87:9f5ac1fabd95 911 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 912 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 913 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 914 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 915 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 916 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 917 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 918
nixnax 61:b3c1a04efd0a 919 // pseudo-header built, now we can calculate TCP checksum
nixnax 29:30de79d658f6 920 checksumtcp[0]=0;
nixnax 29:30de79d658f6 921 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 922 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 923 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 924 checksumtcp[1]=pseudoHeaderSum;
nixnax 87:9f5ac1fabd95 925 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 114:8a5d70bbc1b2 926 dumpHeaderIP(1); // dump outgoing IP header
nixnax 114:8a5d70bbc1b2 927 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 124:18ef53f1d8b7 928 for (int i=0; i<70*1000/10; i++) { // 70 ms delay before sending frame - a typical internet delay time
nixnax 119:e14dd2bf0ea3 929 fillbuf(); // catch any incoming characters
nixnax 124:18ef53f1d8b7 930 wait_us(10); // wait less than 1 character duration at 115200
nixnax 119:e14dd2bf0ea3 931 }
nixnax 93:9675adc36882 932 send_pppFrame(); // All preparation complete - send the TCP response
nixnax 128:e5958d143e9d 933 memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax 29:30de79d658f6 934 }
nixnax 26:11f4eb2663a7 935
nixnax 29:30de79d658f6 936 void dumpDataTCP()
nixnax 29:30de79d658f6 937 {
nixnax 26:11f4eb2663a7 938 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 939 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 940 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 941 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 942 if (v1) {
nixnax 120:bef89e4c906e 943 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 944 fillbuf();
nixnax 120:bef89e4c906e 945 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 120:bef89e4c906e 946 fillbuf();
nixnax 125:ea88200b1df6 947 putsWhileCheckingInput( pbuf );
nixnax 29:30de79d658f6 948 }
nixnax 29:30de79d658f6 949 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 950 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 125:ea88200b1df6 951 putsWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP ); // print the tcp payload data
nixnax 125:ea88200b1df6 952 putsWhileCheckingInput("\n");
nixnax 29:30de79d658f6 953 }
nixnax 29:30de79d658f6 954 }
nixnax 26:11f4eb2663a7 955
nixnax 29:30de79d658f6 956 void TCPpacket()
nixnax 128:e5958d143e9d 957 {
nixnax 114:8a5d70bbc1b2 958 dumpHeaderIP(0); // dump incoming packet header
nixnax 114:8a5d70bbc1b2 959 dumpHeaderTCP(0); // dump incoming packet header
nixnax 128:e5958d143e9d 960 if (v2) dumpDataTCP();
nixnax 26:11f4eb2663a7 961 tcpHandler();
nixnax 11:f58998c24f0b 962 }
nixnax 11:f58998c24f0b 963
nixnax 29:30de79d658f6 964 void otherProtocol()
nixnax 29:30de79d658f6 965 {
nixnax 119:e14dd2bf0ea3 966 debugPrintf("Other IP protocol");
nixnax 29:30de79d658f6 967 }
nixnax 26:11f4eb2663a7 968
nixnax 29:30de79d658f6 969 void IPframe()
nixnax 29:30de79d658f6 970 {
nixnax 10:74f8233f72c0 971 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 972 switch (protocol) {
nixnax 29:30de79d658f6 973 case 1:
nixnax 29:30de79d658f6 974 ICMPpacket();
nixnax 29:30de79d658f6 975 break;
nixnax 29:30de79d658f6 976 case 2:
nixnax 29:30de79d658f6 977 IGMPpacket();
nixnax 29:30de79d658f6 978 break;
nixnax 29:30de79d658f6 979 case 17:
nixnax 29:30de79d658f6 980 UDPpacket();
nixnax 29:30de79d658f6 981 break;
nixnax 29:30de79d658f6 982 case 6:
nixnax 29:30de79d658f6 983 TCPpacket();
nixnax 29:30de79d658f6 984 break;
nixnax 29:30de79d658f6 985 default:
nixnax 29:30de79d658f6 986 otherProtocol();
nixnax 29:30de79d658f6 987 }
nixnax 29:30de79d658f6 988 }
nixnax 9:0992486d4a30 989
nixnax 29:30de79d658f6 990 void LCPconfReq()
nixnax 29:30de79d658f6 991 {
nixnax 119:e14dd2bf0ea3 992 debugPrintf("LCP Config ");
nixnax 9:0992486d4a30 993 if (ppp.pkt.buf[7] != 4) {
nixnax 111:6a3b77c065c0 994 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 119:e14dd2bf0ea3 995 debugPrintf("Reject\n");
nixnax 93:9675adc36882 996 send_pppFrame();
nixnax 9:0992486d4a30 997 } else {
nixnax 9:0992486d4a30 998 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 119:e14dd2bf0ea3 999 debugPrintf("Ack\n");
nixnax 93:9675adc36882 1000 send_pppFrame();
nixnax 119:e14dd2bf0ea3 1001 debugPrintf("LCP Ask\n");
nixnax 11:f58998c24f0b 1002 ppp.pkt.buf[4]=1; // request no options
nixnax 93:9675adc36882 1003 send_pppFrame();
nixnax 9:0992486d4a30 1004 }
nixnax 9:0992486d4a30 1005 }
nixnax 9:0992486d4a30 1006
nixnax 29:30de79d658f6 1007 void LCPconfAck()
nixnax 29:30de79d658f6 1008 {
nixnax 119:e14dd2bf0ea3 1009 debugPrintf("LCP Ack\n");
nixnax 29:30de79d658f6 1010 }
nixnax 9:0992486d4a30 1011
nixnax 29:30de79d658f6 1012 void LCPend()
nixnax 29:30de79d658f6 1013 {
nixnax 29:30de79d658f6 1014 ppp.pkt.buf[4]=6;
nixnax 93:9675adc36882 1015 send_pppFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 1016 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 1017 pppInitStruct(); // flush the receive buffer
nixnax 119:e14dd2bf0ea3 1018 debugPrintf("LCP End\n");
nixnax 9:0992486d4a30 1019 }
nixnax 9:0992486d4a30 1020
nixnax 29:30de79d658f6 1021 void LCPother()
nixnax 29:30de79d658f6 1022 {
nixnax 119:e14dd2bf0ea3 1023 debugPrintf("LCP Other\n");
nixnax 95:40af49390daf 1024 dumpPPPFrame();
nixnax 29:30de79d658f6 1025 }
nixnax 29:30de79d658f6 1026
nixnax 29:30de79d658f6 1027 void LCPframe()
nixnax 29:30de79d658f6 1028 {
nixnax 29:30de79d658f6 1029 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 1030 switch (code) {
nixnax 29:30de79d658f6 1031 case 1:
nixnax 29:30de79d658f6 1032 LCPconfReq();
nixnax 29:30de79d658f6 1033 break; // config request
nixnax 29:30de79d658f6 1034 case 2:
nixnax 29:30de79d658f6 1035 LCPconfAck();
nixnax 29:30de79d658f6 1036 break; // config ack
nixnax 29:30de79d658f6 1037 case 5:
nixnax 29:30de79d658f6 1038 LCPend();
nixnax 29:30de79d658f6 1039 break; // end connection
nixnax 29:30de79d658f6 1040 default:
nixnax 29:30de79d658f6 1041 LCPother();
nixnax 29:30de79d658f6 1042 }
nixnax 9:0992486d4a30 1043 }
nixnax 9:0992486d4a30 1044
nixnax 29:30de79d658f6 1045 void discardedFrame()
nixnax 29:30de79d658f6 1046 {
nixnax 128:e5958d143e9d 1047 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 9:0992486d4a30 1048 }
nixnax 9:0992486d4a30 1049
nixnax 29:30de79d658f6 1050 void determinePacketType()
nixnax 29:30de79d658f6 1051 {
nixnax 29:30de79d658f6 1052 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 119:e14dd2bf0ea3 1053 debugPrintf("byte0 != ff\n");
nixnax 29:30de79d658f6 1054 return;
nixnax 29:30de79d658f6 1055 }
nixnax 29:30de79d658f6 1056 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 119:e14dd2bf0ea3 1057 debugPrintf("byte1 != 3\n");
nixnax 29:30de79d658f6 1058 return;
nixnax 29:30de79d658f6 1059 }
nixnax 29:30de79d658f6 1060 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 119:e14dd2bf0ea3 1061 debugPrintf("byte2 != 21\n");
nixnax 29:30de79d658f6 1062 return;
nixnax 29:30de79d658f6 1063 }
nixnax 9:0992486d4a30 1064 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 1065 switch (packetType) {
nixnax 29:30de79d658f6 1066 case 0xc0:
nixnax 29:30de79d658f6 1067 LCPframe();
nixnax 29:30de79d658f6 1068 break; // link control
nixnax 29:30de79d658f6 1069 case 0x80:
nixnax 29:30de79d658f6 1070 IPCPframe();
nixnax 29:30de79d658f6 1071 break; // IP control
nixnax 29:30de79d658f6 1072 case 0x00:
nixnax 29:30de79d658f6 1073 IPframe();
nixnax 29:30de79d658f6 1074 break; // IP itself
nixnax 29:30de79d658f6 1075 default:
nixnax 29:30de79d658f6 1076 discardedFrame();
nixnax 9:0992486d4a30 1077 }
nixnax 29:30de79d658f6 1078 }
nixnax 9:0992486d4a30 1079
nixnax 128:e5958d143e9d 1080 void wait_for_PPP_frame() // scan the PPP serial input stream for frame start markers
nixnax 50:ad4e7c3c88e5 1081 {
nixnax 85:53e57ff1cf05 1082 while(1) {
nixnax 93:9675adc36882 1083 fillbuf(); // handle received characters
nixnax 124:18ef53f1d8b7 1084 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 81:9ede60e9a2c8 1085 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 1086 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 1087 if (rx==FRAME_7E) {
nixnax 120:bef89e4c906e 1088 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 119:e14dd2bf0ea3 1089 ppp.firstFrame=0;
nixnax 128:e5958d143e9d 1090 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 120:bef89e4c906e 1091 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 119:e14dd2bf0ea3 1092 } else {
nixnax 119:e14dd2bf0ea3 1093 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 119:e14dd2bf0ea3 1094 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 128:e5958d143e9d 1095 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 128:e5958d143e9d 1096 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax 119:e14dd2bf0ea3 1097 break;
nixnax 119:e14dd2bf0ea3 1098 }
nixnax 50:ad4e7c3c88e5 1099 }
nixnax 50:ad4e7c3c88e5 1100 }
nixnax 85:53e57ff1cf05 1101 }
nixnax 50:ad4e7c3c88e5 1102 }
nixnax 50:ad4e7c3c88e5 1103
nixnax 29:30de79d658f6 1104 void scanForConnectString()
nixnax 29:30de79d658f6 1105 {
nixnax 81:9ede60e9a2c8 1106 while(ppp.online == 0) {
nixnax 114:8a5d70bbc1b2 1107 fillbuf(); // gather received characters
nixnax 81:9ede60e9a2c8 1108 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 106:d14e6b597ca3 1109 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 107:5fe806713d49 1110 if (found1 != NULL) {
nixnax 107:5fe806713d49 1111 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 119:e14dd2bf0ea3 1112 if (v0) debugPrintf("Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 107:5fe806713d49 1113 pc.puts("CLIENTSERVER");
nixnax 120:bef89e4c906e 1114 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 119:e14dd2bf0ea3 1115 fillbuf();
nixnax 9:0992486d4a30 1116 }
nixnax 9:0992486d4a30 1117 }
nixnax 103:4f5512dd11cf 1118 }
nixnax 81:9ede60e9a2c8 1119
nixnax 0:2cf4880c312a 1120 int main()
nixnax 0:2cf4880c312a 1121 {
nixnax 128:e5958d143e9d 1122 pc.baud(115200); // USB serial port to pc
nixnax 128:e5958d143e9d 1123 debugBaudRate(115200); // baud rate for our (optional) debug port
nixnax 128:e5958d143e9d 1124 debugPrintf("\x1b[2J\x1b[H\x1b[30mmbed PPP-Blinky HTTP & WebSocket server ready :)\n"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
nixnax 9:0992486d4a30 1125 pppInitStruct(); // initialize all the PPP properties
nixnax 0:2cf4880c312a 1126 while(1) {
nixnax 128:e5958d143e9d 1127 scanForConnectString(); // wait for connect from PC dial-up networking
nixnax 81:9ede60e9a2c8 1128 while(ppp.online) {
nixnax 120:bef89e4c906e 1129 wait_for_PPP_frame(); // wait for a PPP frame
nixnax 81:9ede60e9a2c8 1130 }
nixnax 7:ab147f5e97ac 1131 }
nixnax 105:45001195b325 1132 }