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@129:b8a0b0e8cff1, 2017-08-13 (annotated)

Committer:
nixnax
Date:
Sun Aug 13 11:27:25 2017 +0000
Revision:
129:b8a0b0e8cff1
Parent:
128:e5958d143e9d
Child:
130:45ee0d648a72
Fixed debug print. Added a space to number in GET /x so there is number separation when using curl.

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