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@128:e5958d143e9d, 2017-08-13 (annotated)

Committer:
nixnax
Date:
Sun Aug 13 02:18:18 2017 +0000
Revision:
128:e5958d143e9d
Parent:
127:3ea6f776e287
Child:
129:b8a0b0e8cff1
Added WebSocket Service.; TCP-header checksum bug on odd lfixed.; Comments.;

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