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.

Committer:
nixnax
Date:
Wed Aug 16 11:14:39 2017 +0000
Revision:
134:af9d1f8d451d
Parent:
133:0f5b4085b6d3
Child:
135:6c3eec2fa634
serial port monitor = no.

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 133:0f5b4085b6d3 34 // Special pages in PPP-Blinky
nixnax 133:0f5b4085b6d3 35 // 172.10.10.2/x returns a number that increments every time you request a page - this is handy for testing
nixnax 133:0f5b4085b6d3 36 // 172.10.10.2/xb also returns a number, but issues a fast refresh command. This allows you to use your browser to benchmark page load speed
nixnax 133:0f5b4085b6d3 37 // 172.10.10.2/ws brings up a simple websocket demo
nixnax 128:e5958d143e9d 38
nixnax 93:9675adc36882 39 // Ok, enough talking, time to check out some code!!
nixnax 106:d14e6b597ca3 40
nixnax 81:9ede60e9a2c8 41 #include "mbed.h"
nixnax 128:e5958d143e9d 42 #include "sha1.h"
nixnax 130:45ee0d648a72 43 #include "BufferedSerial.h"
nixnax 131:134b6d0c11e9 44
nixnax 93:9675adc36882 45 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax 66:f005b9fdf4d1 46 // Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor this.
nixnax 110:baec959e1915 47 // Note - the LPC11U24 does NOT have a second serial port
nixnax 134:af9d1f8d451d 48 #define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax 0:2cf4880c312a 49
nixnax 93:9675adc36882 50 // here we define the OPTIONAL, second debug serial port for the various target boards
nixnax 93:9675adc36882 51 // 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 52 // note - if you enable this, some packets may initially be missed which will cause some retransmits
nixnax 114:8a5d70bbc1b2 53 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 128:e5958d143e9d 54 #if defined(TARGET_LPC1768)
nixnax 117:c819ae068336 55 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 56 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
nixnax 117:c819ae068336 57 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 58 #elif defined(TARGET_LPC11U24)
nixnax 117:c819ae068336 59 #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 60 #elif defined (TARGET_KL46Z) || (TARGET_KL25Z)
nixnax 128:e5958d143e9d 61 Serial xx(PTE0,PTE1); // Second serial port on FRDM-KL46Z board
nixnax 118:54d1936e3768 62 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 118:54d1936e3768 63 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 64 #else
nixnax 117:c819ae068336 65 #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 66 #endif
nixnax 119:e14dd2bf0ea3 67 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we print debug messages */
nixnax 119:e14dd2bf0ea3 68 #define debugPutc(x...) xx.putc(x)
nixnax 118:54d1936e3768 69 #define debugBaudRate(x...) xx.baud(x)
nixnax 117:c819ae068336 70 #else
nixnax 119:e14dd2bf0ea3 71 // if we don't have a debug port the debug print functions do nothing
nixnax 119:e14dd2bf0ea3 72 #define debugPrintf(x...) {}
nixnax 119:e14dd2bf0ea3 73 #define debugPutc(x...) {}
nixnax 118:54d1936e3768 74 #define debugBaudRate(x...) {}
nixnax 41:e58a5a09f411 75 #endif
nixnax 41:e58a5a09f411 76
nixnax 110:baec959e1915 77 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 112:30172f36bd33 78 #define v0 1
nixnax 124:18ef53f1d8b7 79 #define v1 0
nixnax 77:abf92baebb42 80 #define v2 0
nixnax 114:8a5d70bbc1b2 81 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 114:8a5d70bbc1b2 82 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 29:30de79d658f6 83
nixnax 93:9675adc36882 84 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 93:9675adc36882 85 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 133:0f5b4085b6d3 86
nixnax 93:9675adc36882 87 const static char rootWebPage[] = "\
nixnax 66:f005b9fdf4d1 88 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 89 <html>\
nixnax 66:f005b9fdf4d1 90 <head>\
nixnax 128:e5958d143e9d 91 <title>mbed PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 92 <script>\
nixnax 66:f005b9fdf4d1 93 window.onload=function(){\
nixnax 66:f005b9fdf4d1 94 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 128:e5958d143e9d 95 x().textContent=parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 96 </script>\
nixnax 66:f005b9fdf4d1 97 </head>\
nixnax 66:f005b9fdf4d1 98 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 99 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 100 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 101 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 102 </body>\
nixnax 133:0f5b4085b6d3 103 </html>"; // 460 characters plus 1 null byte = 461
nixnax 133:0f5b4085b6d3 104
nixnax 133:0f5b4085b6d3 105 const static char webSocketPage[] = "\
nixnax 133:0f5b4085b6d3 106 <!DOCTYPE html>\
nixnax 133:0f5b4085b6d3 107 <html>\
nixnax 133:0f5b4085b6d3 108 <head>\
nixnax 133:0f5b4085b6d3 109 <title>mbed PPP-Blinky</title>\
nixnax 133:0f5b4085b6d3 110 <script>\
nixnax 133:0f5b4085b6d3 111 window.onload=function(){\
nixnax 133:0f5b4085b6d3 112 var url=\"ws://172.10.10.2\";\
nixnax 133:0f5b4085b6d3 113 var sts=document.getElementById(\"sts\");\
nixnax 133:0f5b4085b6d3 114 var btn=document.getElementById(\"btn\");\
nixnax 133:0f5b4085b6d3 115 var ctr=0;\
nixnax 133:0f5b4085b6d3 116 function show(text){sts.textContent=text;}\
nixnax 133:0f5b4085b6d3 117 btn.onclick=function(){\
nixnax 133:0f5b4085b6d3 118 if(btn.textContent==\"Connect\"){\
nixnax 133:0f5b4085b6d3 119 x=new WebSocket(url);\
nixnax 133:0f5b4085b6d3 120 x.onopen=function(){\
nixnax 133:0f5b4085b6d3 121 show(\"Connected to : \"+url);\
nixnax 133:0f5b4085b6d3 122 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 133:0f5b4085b6d3 123 };\
nixnax 133:0f5b4085b6d3 124 x.onclose=function(){show(\"closed\");};\
nixnax 133:0f5b4085b6d3 125 x.onmessage=function(msg){show(\"PPP-Blinky Sent: \\\"\"+msg.data+\"\\\"\");};\
nixnax 133:0f5b4085b6d3 126 } else {\
nixnax 133:0f5b4085b6d3 127 x.send(ctr);\
nixnax 133:0f5b4085b6d3 128 ctr=ctr+1;\
nixnax 133:0f5b4085b6d3 129 btn.textContent=\"Send \\\"\"+ctr+\"\\\"\";\
nixnax 133:0f5b4085b6d3 130 }\
nixnax 133:0f5b4085b6d3 131 };\
nixnax 133:0f5b4085b6d3 132 };\
nixnax 133:0f5b4085b6d3 133 </script>\
nixnax 133:0f5b4085b6d3 134 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 133:0f5b4085b6d3 135 <h4>PPP-Blinky WebSocket Test</h4>\
nixnax 133:0f5b4085b6d3 136 <div id=\"sts\">Idle</div>\
nixnax 133:0f5b4085b6d3 137 <button id=\"btn\" style=\"font-size: 100%; margin-top: 55px; margin-bottom: 55px;\">Connect</button>\
nixnax 133:0f5b4085b6d3 138 <h4><a href=\"/\">PPP-Blinky home</a></h4>\
nixnax 133:0f5b4085b6d3 139 </body>\
nixnax 133:0f5b4085b6d3 140 </html>";
nixnax 69:23f560087c16 141
nixnax 73:2f56ec87dbe9 142 // 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 143 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 72:ad3d12753acf 144 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 145 // See instructions at the top.
nixnax 73:2f56ec87dbe9 146 // 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 132:09b66cc5cf4a 147 BufferedSerial pc(USBTX, USBRX, 100); // usb virtual com port for mbed hardware
nixnax 29:30de79d658f6 148
nixnax 29:30de79d658f6 149 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 150
nixnax 66:f005b9fdf4d1 151 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 152 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 153
nixnax 29:30de79d658f6 154 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 155 struct pppType {
nixnax 38:ab582987926e 156 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 157 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 158 int ledState; // state of LED1
nixnax 98:3babad0d1bd4 159 int httpPageCount;
nixnax 119:e14dd2bf0ea3 160 int firstFrame; // cleared after first frame
nixnax 4:a469050d5b80 161 struct {
nixnax 126:4e1058fa2128 162 #define RXBUFLEN (1<<11)
nixnax 117:c819ae068336 163 // the serial port receive buffer and packet buffer, size is RXBUFLEN (currently 2048 bytes)
nixnax 85:53e57ff1cf05 164 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in ring buffer
nixnax 93:9675adc36882 165 int head;
nixnax 93:9675adc36882 166 int tail;
nixnax 95:40af49390daf 167 int rtail;
nixnax 93:9675adc36882 168 int buflevel;
nixnax 38:ab582987926e 169 } rx; // serial port objects
nixnax 4:a469050d5b80 170 struct {
nixnax 38:ab582987926e 171 int len; // number of bytes in buffer
nixnax 38:ab582987926e 172 int crc; // PPP CRC (frame check)
nixnax 122:963abcbff21e 173 #define PPP_max_size 2500
nixnax 123:fc64fc6caae0 174 // we are assuming 1000 bytes more than MTU size of 1500 - due to the PPP encoding of special bytes
nixnax 122:963abcbff21e 175 char buf[PPP_max_size]; // send and receive buffer large enough for raw, encoded PPP/HDLC frames
nixnax 38:ab582987926e 176 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 177 struct {
nixnax 50:ad4e7c3c88e5 178 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 179 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 180 } hdlc; // hdlc frame objects
nixnax 114:8a5d70bbc1b2 181 struct {
nixnax 114:8a5d70bbc1b2 182 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 114:8a5d70bbc1b2 183 } ip; // ip related object
nixnax 29:30de79d658f6 184 };
nixnax 31:e000c1b9c565 185
nixnax 29:30de79d658f6 186 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 187
nixnax 93:9675adc36882 188 // Initialize our global structure, clear the buffer, etc.
nixnax 29:30de79d658f6 189 void pppInitStruct()
nixnax 29:30de79d658f6 190 {
nixnax 81:9ede60e9a2c8 191 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 29:30de79d658f6 192 ppp.online=0;
nixnax 29:30de79d658f6 193 ppp.rx.tail=0;
nixnax 93:9675adc36882 194 ppp.rx.rtail=0;
nixnax 29:30de79d658f6 195 ppp.rx.head=0;
nixnax 81:9ede60e9a2c8 196 ppp.rx.buflevel=0;
nixnax 29:30de79d658f6 197 ppp.pkt.len=0;
nixnax 114:8a5d70bbc1b2 198 ppp.ip.ident=10000; // easy to recognize in ip packet dumps
nixnax 29:30de79d658f6 199 ppp.ledState=0;
nixnax 81:9ede60e9a2c8 200 ppp.hdlc.frameStartIndex=0;
nixnax 98:3babad0d1bd4 201 ppp.httpPageCount=0;
nixnax 119:e14dd2bf0ea3 202 ppp.firstFrame=1;
nixnax 29:30de79d658f6 203 }
nixnax 26:11f4eb2663a7 204
nixnax 43:aa57db08995d 205 void led1Toggle()
nixnax 43:aa57db08995d 206 {
nixnax 43:aa57db08995d 207 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 93:9675adc36882 208 led1 = ppp.ledState; // toggle led
nixnax 43:aa57db08995d 209 }
nixnax 43:aa57db08995d 210
nixnax 85:53e57ff1cf05 211 // fill our own receive buffer with characters from the PPP serial port
nixnax 85:53e57ff1cf05 212 void fillbuf()
nixnax 0:2cf4880c312a 213 {
nixnax 107:5fe806713d49 214 char ch;
nixnax 85:53e57ff1cf05 215 if ( pc.readable() ) {
nixnax 85:53e57ff1cf05 216 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 93:9675adc36882 217 if ( hd == ppp.rx.rtail ) {
nixnax 119:e14dd2bf0ea3 218 debugPrintf("\nReceive buffer full\n");
nixnax 85:53e57ff1cf05 219 return;
nixnax 83:cdcb81d1910f 220 }
nixnax 107:5fe806713d49 221 ch = pc.getc(); // read new character
nixnax 107:5fe806713d49 222 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 107:5fe806713d49 223 if ( ppp.online == 0 ) {
nixnax 107:5fe806713d49 224 if (ch == 0x7E) {
nixnax 107:5fe806713d49 225 ppp.online = 1;
nixnax 114:8a5d70bbc1b2 226 }
nixnax 114:8a5d70bbc1b2 227 }
nixnax 20:5db9b77b38a6 228 ppp.rx.head = hd; // update head pointer
nixnax 81:9ede60e9a2c8 229 ppp.rx.buflevel++;
nixnax 15:b0154c910143 230 }
nixnax 0:2cf4880c312a 231 }
nixnax 0:2cf4880c312a 232
nixnax 118:54d1936e3768 233 // print to debug port while checking for incoming characters
nixnax 119:e14dd2bf0ea3 234 void putcWhileCheckingInput( char outByte )
nixnax 119:e14dd2bf0ea3 235 {
nixnax 119:e14dd2bf0ea3 236 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 119:e14dd2bf0ea3 237 fillbuf();
nixnax 119:e14dd2bf0ea3 238 debugPutc( outByte );
nixnax 119:e14dd2bf0ea3 239 fillbuf();
nixnax 119:e14dd2bf0ea3 240 #endif
nixnax 119:e14dd2bf0ea3 241 }
nixnax 119:e14dd2bf0ea3 242
nixnax 125:ea88200b1df6 243 void putsWhileCheckingInput( char * data )
nixnax 118:54d1936e3768 244 {
nixnax 118:54d1936e3768 245 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 118:54d1936e3768 246 char * nextChar = data;
nixnax 118:54d1936e3768 247 while( *nextChar != 0 ) {
nixnax 119:e14dd2bf0ea3 248 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 118:54d1936e3768 249 nextChar++;
nixnax 128:e5958d143e9d 250 }
nixnax 118:54d1936e3768 251 #endif
nixnax 118:54d1936e3768 252 }
nixnax 118:54d1936e3768 253
nixnax 124:18ef53f1d8b7 254 // a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 124:18ef53f1d8b7 255 void qq()
nixnax 124:18ef53f1d8b7 256 {
nixnax 125:ea88200b1df6 257 if ( pc.readable() ) putsWhileCheckingInput( "Character available!\n" );
nixnax 124:18ef53f1d8b7 258 }
nixnax 124:18ef53f1d8b7 259
nixnax 118:54d1936e3768 260 void crcReset()
nixnax 118:54d1936e3768 261 {
nixnax 118:54d1936e3768 262 ppp.crc=0xffff; // crc restart
nixnax 118:54d1936e3768 263 }
nixnax 118:54d1936e3768 264
nixnax 118:54d1936e3768 265 void crcDo(int x) // cumulative crc
nixnax 118:54d1936e3768 266 {
nixnax 118:54d1936e3768 267 for (int i=0; i<8; i++) {
nixnax 118:54d1936e3768 268 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 118:54d1936e3768 269 x>>=1;
nixnax 118:54d1936e3768 270 }
nixnax 124:18ef53f1d8b7 271 fillbuf(); // handle input
nixnax 118:54d1936e3768 272 }
nixnax 118:54d1936e3768 273
nixnax 118:54d1936e3768 274 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 118:54d1936e3768 275 {
nixnax 118:54d1936e3768 276 crcReset();
nixnax 118:54d1936e3768 277 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 118:54d1936e3768 278 return ppp.crc;
nixnax 118:54d1936e3768 279 }
nixnax 118:54d1936e3768 280
nixnax 85:53e57ff1cf05 281 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 282 {
nixnax 63:9253b0e1b7d8 283 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 81:9ede60e9a2c8 284 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 81:9ede60e9a2c8 285 ppp.rx.buflevel--;
nixnax 63:9253b0e1b7d8 286 return x;
nixnax 0:2cf4880c312a 287 }
nixnax 0:2cf4880c312a 288
nixnax 95:40af49390daf 289 // Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 95:40af49390daf 290 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 95:40af49390daf 291 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 95:40af49390daf 292 void dumpPPPFrame()
nixnax 95:40af49390daf 293 {
nixnax 120:bef89e4c906e 294 char pbuf[30];
nixnax 120:bef89e4c906e 295 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 124:18ef53f1d8b7 296 fillbuf();
nixnax 124:18ef53f1d8b7 297 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 124:18ef53f1d8b7 298 fillbuf();
nixnax 125:ea88200b1df6 299 putsWhileCheckingInput(pbuf);
nixnax 124:18ef53f1d8b7 300 }
nixnax 124:18ef53f1d8b7 301 fillbuf();
nixnax 124:18ef53f1d8b7 302 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 124:18ef53f1d8b7 303 fillbuf();
nixnax 125:ea88200b1df6 304 putsWhileCheckingInput(pbuf);
nixnax 95:40af49390daf 305 }
nixnax 95:40af49390daf 306
nixnax 119:e14dd2bf0ea3 307 void processPPPFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 308 {
nixnax 38:ab582987926e 309 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 310 if(start==end) {
nixnax 111:6a3b77c065c0 311 return; // empty frame
nixnax 29:30de79d658f6 312 }
nixnax 9:0992486d4a30 313 crcReset();
nixnax 9:0992486d4a30 314 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 315 ppp.pkt.len=0;
nixnax 9:0992486d4a30 316 int unstuff=0;
nixnax 17:4918c893d802 317 int idx = start;
nixnax 17:4918c893d802 318 while(1) {
nixnax 124:18ef53f1d8b7 319 fillbuf();
nixnax 9:0992486d4a30 320 if (unstuff==0) {
nixnax 72:ad3d12753acf 321 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 322 else {
nixnax 72:ad3d12753acf 323 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 324 ppp.pkt.len++;
nixnax 29:30de79d658f6 325 dest++;
nixnax 72:ad3d12753acf 326 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 327 }
nixnax 66:f005b9fdf4d1 328 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 329 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 330 ppp.pkt.len++;
nixnax 29:30de79d658f6 331 dest++;
nixnax 72:ad3d12753acf 332 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 333 unstuff=0;
nixnax 9:0992486d4a30 334 }
nixnax 81:9ede60e9a2c8 335 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 336 if (idx == end) break;
nixnax 9:0992486d4a30 337 }
nixnax 29:30de79d658f6 338 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 120:bef89e4c906e 339 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 9:0992486d4a30 340 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 341 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 342 determinePacketType();
nixnax 90:55e0f243a7ce 343 } else {
nixnax 130:45ee0d648a72 344 #define REPORT_FCS_ERROR_YES
nixnax 128:e5958d143e9d 345 #ifdef REPORT_FCS_ERROR_YES
nixnax 128:e5958d143e9d 346 char pbuf[50]; // local print buffer
nixnax 128:e5958d143e9d 347 fillbuf();
nixnax 128:e5958d143e9d 348 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 128:e5958d143e9d 349 fillbuf();
nixnax 128:e5958d143e9d 350 putsWhileCheckingInput( pbuf );
nixnax 128:e5958d143e9d 351 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 128:e5958d143e9d 352 #endif
nixnax 9:0992486d4a30 353 }
nixnax 9:0992486d4a30 354 }
nixnax 9:0992486d4a30 355
nixnax 124:18ef53f1d8b7 356 void pcPutcWhileCheckingInput(int ch)
nixnax 124:18ef53f1d8b7 357 {
nixnax 124:18ef53f1d8b7 358 fillbuf(); // check input
nixnax 124:18ef53f1d8b7 359 pc.putc(ch);
nixnax 124:18ef53f1d8b7 360 fillbuf();
nixnax 124:18ef53f1d8b7 361 }
nixnax 124:18ef53f1d8b7 362
nixnax 29:30de79d658f6 363 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 364 {
nixnax 29:30de79d658f6 365 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 124:18ef53f1d8b7 366 pcPutcWhileCheckingInput(0x7d);
nixnax 124:18ef53f1d8b7 367 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 368 } else {
nixnax 124:18ef53f1d8b7 369 pcPutcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 370 }
nixnax 11:f58998c24f0b 371 }
nixnax 9:0992486d4a30 372
nixnax 93:9675adc36882 373 void send_pppFrame() // send a PPP frame in HDLC format
nixnax 133:0f5b4085b6d3 374 {
nixnax 17:4918c893d802 375 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 376 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 377 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 124:18ef53f1d8b7 378 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 95:40af49390daf 379 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 133:0f5b4085b6d3 380 wait_us(86); // wait one character time
nixnax 133:0f5b4085b6d3 381 fillbuf();
nixnax 93:9675adc36882 382 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 93:9675adc36882 383 }
nixnax 124:18ef53f1d8b7 384 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 385 }
nixnax 9:0992486d4a30 386
nixnax 93:9675adc36882 387 void ipcpConfigRequestHandler()
nixnax 29:30de79d658f6 388 {
nixnax 119:e14dd2bf0ea3 389 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 92:cb962b365cce 390 ppp.pkt.buf[4]=2; // change code to ack
nixnax 108:f77ec4605945 391 send_pppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 106:d14e6b597ca3 392
nixnax 119:e14dd2bf0ea3 393 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 92:cb962b365cce 394 ppp.pkt.buf[4]=1; // change code to request
nixnax 106:d14e6b597ca3 395 ppp.pkt.buf[7]=4; // no options in this request
nixnax 106:d14e6b597ca3 396 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 128:e5958d143e9d 397 send_pppFrame(); // send our request
nixnax 9:0992486d4a30 398 }
nixnax 9:0992486d4a30 399
nixnax 93:9675adc36882 400 void ipcpAckHandler()
nixnax 29:30de79d658f6 401 {
nixnax 119:e14dd2bf0ea3 402 debugPrintf("Their IPCP Grant\n");
nixnax 29:30de79d658f6 403 }
nixnax 9:0992486d4a30 404
nixnax 93:9675adc36882 405 void ipcpNackHandler()
nixnax 29:30de79d658f6 406 {
nixnax 119:e14dd2bf0ea3 407 debugPrintf("Their IPCP Nack, Our ACK\n");
nixnax 107:5fe806713d49 408 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 106:d14e6b597ca3 409 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 106:d14e6b597ca3 410 send_pppFrame(); // let's request this IP address as ours
nixnax 106:d14e6b597ca3 411 } // if it's not an IP nack we ignore it
nixnax 29:30de79d658f6 412 }
nixnax 9:0992486d4a30 413
nixnax 93:9675adc36882 414 void ipcpDefaultHandler()
nixnax 29:30de79d658f6 415 {
nixnax 119:e14dd2bf0ea3 416 debugPrintf("Their IPCP Other\n");
nixnax 29:30de79d658f6 417 }
nixnax 29:30de79d658f6 418
nixnax 29:30de79d658f6 419 void IPCPframe()
nixnax 29:30de79d658f6 420 {
nixnax 9:0992486d4a30 421 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 422 switch (code) {
nixnax 29:30de79d658f6 423 case 1:
nixnax 93:9675adc36882 424 ipcpConfigRequestHandler();
nixnax 29:30de79d658f6 425 break;
nixnax 29:30de79d658f6 426 case 2:
nixnax 93:9675adc36882 427 ipcpAckHandler();
nixnax 29:30de79d658f6 428 break;
nixnax 29:30de79d658f6 429 case 3:
nixnax 93:9675adc36882 430 ipcpNackHandler();
nixnax 29:30de79d658f6 431 break;
nixnax 29:30de79d658f6 432 default:
nixnax 93:9675adc36882 433 ipcpDefaultHandler();
nixnax 9:0992486d4a30 434 }
nixnax 29:30de79d658f6 435 }
nixnax 9:0992486d4a30 436
nixnax 29:30de79d658f6 437 void UDPpacket()
nixnax 29:30de79d658f6 438 {
nixnax 12:db0dc91f0231 439 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 440 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 441 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 118:54d1936e3768 442 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 443 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 444 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 445 #endif
nixnax 12:db0dc91f0231 446 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 447 char * udpInf = udpBlock+8; // actual start of info
nixnax 118:54d1936e3768 448 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 449 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 450 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 451 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 452 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 453 #endif
nixnax 29:30de79d658f6 454 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 455 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 119:e14dd2bf0ea3 456 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 119:e14dd2bf0ea3 457 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 119:e14dd2bf0ea3 458 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 29:30de79d658f6 459 int printSize = udpLength;
nixnax 29:30de79d658f6 460 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 461 if (v1) {
nixnax 29:30de79d658f6 462 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 463 char ch = udpInf[i];
nixnax 29:30de79d658f6 464 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 465 debugPrintf("%c", ch);
nixnax 29:30de79d658f6 466 } else {
nixnax 119:e14dd2bf0ea3 467 debugPrintf("_");
nixnax 29:30de79d658f6 468 }
nixnax 29:30de79d658f6 469 }
nixnax 29:30de79d658f6 470 }
nixnax 119:e14dd2bf0ea3 471 if (v0) debugPrintf("\n");
nixnax 12:db0dc91f0231 472 }
nixnax 11:f58998c24f0b 473
nixnax 76:00e208cceb8b 474 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 475 {
nixnax 128:e5958d143e9d 476 unsigned int i,hi,lo,sum;
nixnax 76:00e208cceb8b 477 unsigned char placeHolder;
nixnax 29:30de79d658f6 478 if (len&1) {
nixnax 128:e5958d143e9d 479 placeHolder = ptr[len];
nixnax 128:e5958d143e9d 480 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 481 }
nixnax 128:e5958d143e9d 482 sum=0;
nixnax 128:e5958d143e9d 483 i=0;
nixnax 128:e5958d143e9d 484 while ( i<len ) {
nixnax 124:18ef53f1d8b7 485 fillbuf();
nixnax 128:e5958d143e9d 486 hi = ptr[i++];
nixnax 128:e5958d143e9d 487 lo = ptr[i++];
nixnax 128:e5958d143e9d 488 sum = sum + ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 489 }
nixnax 29:30de79d658f6 490 if (len&1) {
nixnax 128:e5958d143e9d 491 ptr[len] = placeHolder; // restore the extra byte we made zero
nixnax 29:30de79d658f6 492 }
nixnax 76:00e208cceb8b 493 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 494 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 495 return ~sum;
nixnax 29:30de79d658f6 496 }
nixnax 11:f58998c24f0b 497
nixnax 29:30de79d658f6 498 void headerCheckSum()
nixnax 29:30de79d658f6 499 {
nixnax 11:f58998c24f0b 500 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 501 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 502 int sum=0;
nixnax 11:f58998c24f0b 503
nixnax 29:30de79d658f6 504 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 505 int hi = *ptr;
nixnax 29:30de79d658f6 506 ptr++;
nixnax 29:30de79d658f6 507 int lo = *ptr;
nixnax 29:30de79d658f6 508 ptr++;
nixnax 11:f58998c24f0b 509 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 510 sum = sum + val;
nixnax 124:18ef53f1d8b7 511 fillbuf();
nixnax 11:f58998c24f0b 512 }
nixnax 11:f58998c24f0b 513 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 514 sum = ~sum;
nixnax 11:f58998c24f0b 515 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 516 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 517 }
nixnax 9:0992486d4a30 518
nixnax 29:30de79d658f6 519 void ICMPpacket() // internet control message protocol
nixnax 128:e5958d143e9d 520 {
nixnax 12:db0dc91f0231 521 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 522 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 523 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 524 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 525 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 526 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 527 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 528 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 529 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 530 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 531 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 532 char * dstAdr = ipPkt+16;
nixnax 124:18ef53f1d8b7 533 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 18:3e35de1bc877 534 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 535 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 125:ea88200b1df6 536 if(1) {
nixnax 124:18ef53f1d8b7 537 char pbuf[50];
nixnax 124:18ef53f1d8b7 538 fillbuf();
nixnax 124:18ef53f1d8b7 539 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 540 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 541 fillbuf();
nixnax 125:ea88200b1df6 542 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 124:18ef53f1d8b7 543 fillbuf();
nixnax 125:ea88200b1df6 544 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 545 }
nixnax 128:e5958d143e9d 546 #endif
nixnax 29:30de79d658f6 547 char src[4];
nixnax 29:30de79d658f6 548 char dst[4];
nixnax 12:db0dc91f0231 549 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 550 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 551 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 552 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 553 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 554 chkSum[0]=0;
nixnax 29:30de79d658f6 555 chkSum[1]=0;
nixnax 12:db0dc91f0231 556 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 557 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 558 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 559 icmpSum[0]=0;
nixnax 29:30de79d658f6 560 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 561 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 562 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 563 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 564 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 565
nixnax 16:cb0b80c24ba2 566 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 567 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 568 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 124:18ef53f1d8b7 569 if (0) {
nixnax 29:30de79d658f6 570 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 571 char ch = icmpData[i];
nixnax 29:30de79d658f6 572 if (ch>31 && ch<127) {
nixnax 124:18ef53f1d8b7 573 putcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 574 } else {
nixnax 124:18ef53f1d8b7 575 putcWhileCheckingInput('_');
nixnax 29:30de79d658f6 576 }
nixnax 29:30de79d658f6 577 }
nixnax 124:18ef53f1d8b7 578 putcWhileCheckingInput('\n');
nixnax 29:30de79d658f6 579 }
nixnax 93:9675adc36882 580 send_pppFrame(); // reply to the ping
nixnax 12:db0dc91f0231 581 } else {
nixnax 29:30de79d658f6 582 if (v0) {
nixnax 119:e14dd2bf0ea3 583 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 584 }
nixnax 128:e5958d143e9d 585 }
nixnax 11:f58998c24f0b 586 }
nixnax 11:f58998c24f0b 587
nixnax 29:30de79d658f6 588 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 589 {
nixnax 119:e14dd2bf0ea3 590 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 591 }
nixnax 11:f58998c24f0b 592
nixnax 114:8a5d70bbc1b2 593 void dumpHeaderIP (int outGoing)
nixnax 29:30de79d658f6 594 {
nixnax 114:8a5d70bbc1b2 595 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 119:e14dd2bf0ea3 596 fillbuf(); // we are expecting the first character of the next packet
nixnax 114:8a5d70bbc1b2 597 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 114:8a5d70bbc1b2 598 char * ident = ipPkt+4; // 2 bytes
nixnax 118:54d1936e3768 599 #ifdef UNUSED_IP_VARIABLES
nixnax 114:8a5d70bbc1b2 600 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 114:8a5d70bbc1b2 601 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 114:8a5d70bbc1b2 602 char * version = ipPkt; // top 4 bits
nixnax 114:8a5d70bbc1b2 603 char * ihl = ipPkt; // bottom 4 bits
nixnax 114:8a5d70bbc1b2 604 char * dscp = ipPkt+1; // top 6 bits
nixnax 114:8a5d70bbc1b2 605 char * ecn = ipPkt+1; // lower 2 bits
nixnax 114:8a5d70bbc1b2 606 char * pktLen = ipPkt+2; // 2 bytes
nixnax 114:8a5d70bbc1b2 607 char * flags = ipPkt+6; // 2 bits
nixnax 114:8a5d70bbc1b2 608 char * ttl = ipPkt+8; // 1 byte
nixnax 114:8a5d70bbc1b2 609 char * protocol = ipPkt+9; // 1 byte
nixnax 114:8a5d70bbc1b2 610 char * headercheck= ipPkt+10; // 2 bytes
nixnax 114:8a5d70bbc1b2 611 int versionIP = (version[0]>>4)&0xf;
nixnax 114:8a5d70bbc1b2 612 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 114:8a5d70bbc1b2 613 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 114:8a5d70bbc1b2 614 int ecnIP = ecn[0]&3;
nixnax 114:8a5d70bbc1b2 615 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 114:8a5d70bbc1b2 616 int flagsIP = flags[0]>>14&3;
nixnax 114:8a5d70bbc1b2 617 int ttlIP = ttl[0];
nixnax 114:8a5d70bbc1b2 618 int protocolIP = protocol[0];
nixnax 114:8a5d70bbc1b2 619 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 620 #endif
nixnax 119:e14dd2bf0ea3 621 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 119:e14dd2bf0ea3 622 char pbuf[50]; // local print buffer
nixnax 118:54d1936e3768 623 int n=0;
nixnax 119:e14dd2bf0ea3 624 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 119:e14dd2bf0ea3 625 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 626 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 627 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 628 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 119:e14dd2bf0ea3 629 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 119:e14dd2bf0ea3 630 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 631 #endif
nixnax 125:ea88200b1df6 632 putsWhileCheckingInput( pbuf );
nixnax 114:8a5d70bbc1b2 633 #ifndef TCP_HEADER_DUMP_YES
nixnax 125:ea88200b1df6 634 putsWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 114:8a5d70bbc1b2 635 #endif
nixnax 114:8a5d70bbc1b2 636 #endif
nixnax 29:30de79d658f6 637 }
nixnax 26:11f4eb2663a7 638
nixnax 114:8a5d70bbc1b2 639 void dumpHeaderTCP(int outGoing)
nixnax 29:30de79d658f6 640 {
nixnax 114:8a5d70bbc1b2 641 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 114:8a5d70bbc1b2 642 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 114:8a5d70bbc1b2 643 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 114:8a5d70bbc1b2 644 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 114:8a5d70bbc1b2 645 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 114:8a5d70bbc1b2 646 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 114:8a5d70bbc1b2 647 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 114:8a5d70bbc1b2 648 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 114:8a5d70bbc1b2 649 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 114:8a5d70bbc1b2 650 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 119:e14dd2bf0ea3 651 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 119:e14dd2bf0ea3 652 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 119:e14dd2bf0ea3 653 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 114:8a5d70bbc1b2 654 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 114:8a5d70bbc1b2 655 flagInfo[8]=0; // null terminate string
nixnax 114:8a5d70bbc1b2 656 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 114:8a5d70bbc1b2 657 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 114:8a5d70bbc1b2 658 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 114:8a5d70bbc1b2 659 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 114:8a5d70bbc1b2 660 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 114:8a5d70bbc1b2 661 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 114:8a5d70bbc1b2 662 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 114:8a5d70bbc1b2 663 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 118:54d1936e3768 664 #else
nixnax 119:e14dd2bf0ea3 665 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 119:e14dd2bf0ea3 666 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 119:e14dd2bf0ea3 667 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 119:e14dd2bf0ea3 668 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 119:e14dd2bf0ea3 669 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 124:18ef53f1d8b7 670 flagInfo[1]=0; // ' '
nixnax 119:e14dd2bf0ea3 671 flagInfo[2]=0;
nixnax 118:54d1936e3768 672 #endif
nixnax 125:ea88200b1df6 673 putsWhileCheckingInput( flagInfo );
nixnax 119:e14dd2bf0ea3 674 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 675 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 125:ea88200b1df6 676 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 119:e14dd2bf0ea3 677 #endif
nixnax 119:e14dd2bf0ea3 678 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 119:e14dd2bf0ea3 679 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 118:54d1936e3768 680 }
nixnax 114:8a5d70bbc1b2 681 #endif
nixnax 29:30de79d658f6 682 }
nixnax 29:30de79d658f6 683
nixnax 128:e5958d143e9d 684 void enc64(char * in, char * out, int len)
nixnax 128:e5958d143e9d 685 {
nixnax 128:e5958d143e9d 686 const static char lut [] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
nixnax 128:e5958d143e9d 687 int i,j,a,b,c;
nixnax 128:e5958d143e9d 688 i=0;
nixnax 128:e5958d143e9d 689 j=0;
nixnax 128:e5958d143e9d 690 while(1) {
nixnax 128:e5958d143e9d 691 if (i<len) {
nixnax 128:e5958d143e9d 692 a = in[i++];
nixnax 128:e5958d143e9d 693 out[j++] = lut[ ( (a >> 2) & 0x3f) ];
nixnax 128:e5958d143e9d 694 } else break;
nixnax 128:e5958d143e9d 695 if (i<len) {
nixnax 128:e5958d143e9d 696 b = in[i++];
nixnax 128:e5958d143e9d 697 out[j++] = lut[ ( (a << 4) & 0x30) | ( (b >> 4) & 0x0f) ];
nixnax 128:e5958d143e9d 698 out[j++] = lut[ ( (b << 2) & 0x3c) ];
nixnax 128:e5958d143e9d 699 } else out[j++] = '=';
nixnax 128:e5958d143e9d 700 if (i<len) {
nixnax 128:e5958d143e9d 701 c = in[i++];
nixnax 128:e5958d143e9d 702 j--;
nixnax 128:e5958d143e9d 703 out[j++] = lut[ ( (b << 2) & 0x3c) | ( (c >> 6) & 0x03) ];
nixnax 128:e5958d143e9d 704 out[j++] = lut[ ( (c >> 0) & 0x3f) ];
nixnax 128:e5958d143e9d 705 } else out[j++] = '=';
nixnax 128:e5958d143e9d 706 }
nixnax 128:e5958d143e9d 707 out[j]=0;
nixnax 128:e5958d143e9d 708 }
nixnax 128:e5958d143e9d 709
nixnax 128:e5958d143e9d 710 // 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 711 int webSocketHandler(char * dataStart)
nixnax 128:e5958d143e9d 712 {
nixnax 128:e5958d143e9d 713 int n=0; // byte counter
nixnax 128:e5958d143e9d 714 char * key = strstr(dataStart, "Sec-WebSocket-Key: "); // search for the key in the payload
nixnax 128:e5958d143e9d 715 if (key != NULL) {
nixnax 129:b8a0b0e8cff1 716 if (v0) putsWhileCheckingInput("WebSocket Request\n");
nixnax 128:e5958d143e9d 717 char challenge [70];
nixnax 128:e5958d143e9d 718 strncpy(challenge,key+19,70); // a local buffer
nixnax 128:e5958d143e9d 719 *strchr(challenge,'\r')=0; // insert null so we can use sprintf
nixnax 128:e5958d143e9d 720 strncat(challenge,"258EAFA5-E914-47DA-95CA-C5AB0DC85B11",70); // append websocket gui code
nixnax 128:e5958d143e9d 721 char shaOutput [20]; // sha1 output
nixnax 128:e5958d143e9d 722 sha1( shaOutput, challenge, strlen(challenge));
nixnax 128:e5958d143e9d 723 char encOut[50];
nixnax 128:e5958d143e9d 724 enc64( shaOutput, encOut, 20);
nixnax 128:e5958d143e9d 725 char * versionstring = strstr(dataStart, "Sec-WebSocket-Version:");
nixnax 128:e5958d143e9d 726 char * version = challenge;
nixnax 128:e5958d143e9d 727 strncpy(version, versionstring,70); // copy version string
nixnax 128:e5958d143e9d 728 *strchr(version,'\r')=0; // null terminate so we can sprintf it
nixnax 128:e5958d143e9d 729 memset(dataStart,0,500); // blank out old data befor send the websocket response header
nixnax 128:e5958d143e9d 730 n=n+sprintf(dataStart+n, "HTTP/1.1 101 Switching Protocols\r\n");
nixnax 128:e5958d143e9d 731 n=n+sprintf(dataStart+n, "Upgrade: websocket\r\n");
nixnax 128:e5958d143e9d 732 n=n+sprintf(dataStart+n, "Connection: Upgrade\r\n");
nixnax 128:e5958d143e9d 733 n=n+sprintf(dataStart+n, "Sec-WebSocket-Accept: %s\r\n",encOut);
nixnax 128:e5958d143e9d 734 n=n+sprintf(dataStart+n, "%s\r\n",version);
nixnax 128:e5958d143e9d 735 n=n+sprintf(dataStart+n, "mbed-Code: PPP-Blinky\r\n");
nixnax 128:e5958d143e9d 736 n=n+sprintf(dataStart+n, "\r\n"); // websocket response header ending
nixnax 128:e5958d143e9d 737 }
nixnax 128:e5958d143e9d 738 return n; // this response should satisfy a web browser's websocket protocol request
nixnax 128:e5958d143e9d 739 }
nixnax 128:e5958d143e9d 740
nixnax 128:e5958d143e9d 741 #define TCP_FLAG_ACK (1<<4)
nixnax 128:e5958d143e9d 742 #define TCP_FLAG_SYN (1<<1)
nixnax 128:e5958d143e9d 743 #define TCP_FLAG_PSH (1<<3)
nixnax 128:e5958d143e9d 744 #define TCP_FLAG_RST (1<<2)
nixnax 128:e5958d143e9d 745 #define TCP_FLAG_FIN (1<<0)
nixnax 128:e5958d143e9d 746
nixnax 68:0b74763ae67f 747 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 748 {
nixnax 67:a63e3486bcda 749 int n=0; // number of bytes we have printed so far
nixnax 128:e5958d143e9d 750 n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
nixnax 128:e5958d143e9d 751 if (n>0) return n; // if it's a WebSocket we already have the response, so return
nixnax 128:e5958d143e9d 752
nixnax 77:abf92baebb42 753 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 754 int contentLengthStart; // index where HTML starts
nixnax 133:0f5b4085b6d3 755 int httpGet5,httpGet6,httpGetx, httpGetRoot; // temporary storage of strncmp results
nixnax 85:53e57ff1cf05 756
nixnax 98:3babad0d1bd4 757 ppp.httpPageCount++; // increment the number of frames we have made
nixnax 85:53e57ff1cf05 758
nixnax 128:e5958d143e9d 759 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found a GET to the root directory
nixnax 128:e5958d143e9d 760 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 133:0f5b4085b6d3 761 httpGet5 = dataStart[5]; // the first character in the path name, we use it for special functions later on
nixnax 133:0f5b4085b6d3 762 httpGet6 = dataStart[6]; // the second character in the path name, we use it for special functions later on
nixnax 119:e14dd2bf0ea3 763 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 128:e5958d143e9d 764 if( (httpGetRoot==0) || (httpGetx==0) ) {
nixnax 133:0f5b4085b6d3 765 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky-v1\r\n"); // 200 OK header
nixnax 83:cdcb81d1910f 766 } else {
nixnax 89:2c8dd0c2a426 767 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 83:cdcb81d1910f 768 }
nixnax 83:cdcb81d1910f 769 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 770 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 771 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 772 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 773 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 774 nHeader=n; // size of HTTP header
nixnax 93:9675adc36882 775 if( httpGetRoot == 0 ) {
nixnax 83:cdcb81d1910f 776 // this is where we insert our web page into the buffer
nixnax 93:9675adc36882 777 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 133:0f5b4085b6d3 778 n = n + sizeof(rootWebPage)-1; // one less than sizeof because we don't count the null byte at the end
nixnax 133:0f5b4085b6d3 779 } else if ( (httpGet5 == 'w') && (httpGet6 == 's') ) { // "ws" is a special page for websocket demo
nixnax 133:0f5b4085b6d3 780 memcpy(n+dataStart,webSocketPage,sizeof(webSocketPage));
nixnax 133:0f5b4085b6d3 781 n = n + sizeof(webSocketPage)-1; // one less than size
nixnax 85:53e57ff1cf05 782 } else {
nixnax 128:e5958d143e9d 783 if (httpGetx == 0) { // the page request started with "GET /x" - here we treat anything starting with /x special:
nixnax 89:2c8dd0c2a426 784
nixnax 89:2c8dd0c2a426 785 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 89:2c8dd0c2a426 786 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 89:2c8dd0c2a426 787 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 128:e5958d143e9d 788 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (W3C.org required elements)
nixnax 98:3babad0d1bd4 789 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.httpPageCount); // body = the http frame count
nixnax 89:2c8dd0c2a426 790 #else
nixnax 133:0f5b4085b6d3 791 if( httpGet6 == 'b' ) { // if the fetched page is "xb" send a meta command to let the browser continuously reload
nixnax 133:0f5b4085b6d3 792 n=n+sprintf(n+dataStart, "<meta http-equiv=\"refresh\" content=\"0\">"); // reload loop - handy for benchmarking
nixnax 133:0f5b4085b6d3 793 }
nixnax 128:e5958d143e9d 794 // /x is a very short page, in fact, it is only a decimal number showing the http Page count
nixnax 133:0f5b4085b6d3 795 n=n+sprintf(n+dataStart,"%d ",ppp.httpPageCount); // not really valid html but most browsers and curl are ok with it
nixnax 89:2c8dd0c2a426 796 #endif
nixnax 89:2c8dd0c2a426 797 } else {
nixnax 89:2c8dd0c2a426 798 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 128:e5958d143e9d 799 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed PPP-Blinky</title>"); // html title (required element)
nixnax 89:2c8dd0c2a426 800 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 89:2c8dd0c2a426 801 }
nixnax 83:cdcb81d1910f 802 }
nixnax 83:cdcb81d1910f 803 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 804 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 805 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 806 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 807 return n; // total byte size of our response
nixnax 67:a63e3486bcda 808 }
nixnax 67:a63e3486bcda 809
nixnax 128:e5958d143e9d 810 // this is the response if we have TCP data but it's not an HTTP GET
nixnax 98:3babad0d1bd4 811 // this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 128:e5958d143e9d 812 // this could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
nixnax 128:e5958d143e9d 813 int tcpResponse(char * dataStart, int len, int * outFlags)
nixnax 98:3babad0d1bd4 814 {
nixnax 98:3babad0d1bd4 815 int n=0; // number of bytes we have printed so far
nixnax 128:e5958d143e9d 816 if (dataStart[0] == 0x81) { // check if this is a websocket push message
nixnax 128:e5958d143e9d 817 // 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 818 if (0) putsWhileCheckingInput( "Got data from websocket send()\n" );
nixnax 128:e5958d143e9d 819
nixnax 128:e5958d143e9d 820 // for now we simply echo the websocket data back to the client - the client should therefore see an onmessage event
nixnax 128:e5958d143e9d 821 // 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 822 if (1) {
nixnax 128:e5958d143e9d 823 char mask [4];
nixnax 128:e5958d143e9d 824 memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
nixnax 128:e5958d143e9d 825 int websocketMessageSize = len - 6; // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
nixnax 128:e5958d143e9d 826 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 827 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 828 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 829 memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
nixnax 128:e5958d143e9d 830 n = len; // our response size remains exactly the same length as what we received
nixnax 128:e5958d143e9d 831 }
nixnax 128:e5958d143e9d 832 } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
nixnax 131:134b6d0c11e9 833 n=2; // our close command is only two bytes long because we don't use the four mask bytes
nixnax 131:134b6d0c11e9 834 dataStart[1]=0; // we don't have mask bytes on
nixnax 128:e5958d143e9d 835 } else if (v1) putsWhileCheckingInput("TCP data received\n");
nixnax 98:3babad0d1bd4 836 return n; // total byte size of our response
nixnax 98:3babad0d1bd4 837 }
nixnax 98:3babad0d1bd4 838
nixnax 29:30de79d658f6 839 void tcpHandler()
nixnax 29:30de79d658f6 840 {
nixnax 87:9f5ac1fabd95 841 // IP header
nixnax 26:11f4eb2663a7 842 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 843 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 844 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 845 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 846 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 847 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 848 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 849 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 850 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 851 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 852
nixnax 87:9f5ac1fabd95 853 // TCP header
nixnax 87:9f5ac1fabd95 854 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 87:9f5ac1fabd95 855 char * srctcp = tcp + 0; // 2 bytes
nixnax 87:9f5ac1fabd95 856 char * dsttcp = tcp + 2; // 2 bytes
nixnax 87:9f5ac1fabd95 857 char * seqtcp = tcp + 4; // 4 bytes
nixnax 87:9f5ac1fabd95 858 char * acktcp = tcp + 8; // 4 bytes
nixnax 87:9f5ac1fabd95 859 char * offset = tcp + 12; // 4 bits
nixnax 87:9f5ac1fabd95 860 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 87:9f5ac1fabd95 861 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 87:9f5ac1fabd95 862 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 128:e5958d143e9d 863
nixnax 124:18ef53f1d8b7 864 if(ident) {}; // shut up unused variable reference warning
nixnax 26:11f4eb2663a7 865 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 866 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 867 int protocolIP = protocol[0];
nixnax 87:9f5ac1fabd95 868 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 869 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 87:9f5ac1fabd95 870 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 85:53e57ff1cf05 871 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 85:53e57ff1cf05 872 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 85:53e57ff1cf05 873 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 87:9f5ac1fabd95 874 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 81:9ede60e9a2c8 875
nixnax 128:e5958d143e9d 876 // first we shorten the TCP response header to only 20 bytes. This means we ignore all TCP option requests
nixnax 87:9f5ac1fabd95 877 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 87:9f5ac1fabd95 878 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 87:9f5ac1fabd95 879 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 87:9f5ac1fabd95 880 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 881 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 882 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 883
nixnax 35:e7068df4d971 884 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 885 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 87:9f5ac1fabd95 886 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 119:e14dd2bf0ea3 887 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 119:e14dd2bf0ea3 888 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 38:ab582987926e 889
nixnax 106:d14e6b597ca3 890 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 77:abf92baebb42 891
nixnax 69:23f560087c16 892 switch ( flagsTCP ) {
nixnax 128:e5958d143e9d 893 case TCP_FLAG_ACK:
nixnax 128:e5958d143e9d 894 return;
nixnax 69:23f560087c16 895 case TCP_FLAG_SYN:
nixnax 87:9f5ac1fabd95 896 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 119:e14dd2bf0ea3 897 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 85:53e57ff1cf05 898 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 899 break;
nixnax 77:abf92baebb42 900 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 128:e5958d143e9d 901 if ( (strncmp(tcpDataIn, "GET /", 5) == 0) ) { // check for an http GET command
nixnax 128:e5958d143e9d 902 flagsOut = TCP_FLAG_ACK | TCP_FLAG_PSH; // set outgoing FIN flag to ask them to close from their side
nixnax 87:9f5ac1fabd95 903 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 98:3babad0d1bd4 904 } else {
nixnax 128:e5958d143e9d 905 dataLen = tcpResponse(tcpDataOut,tcpDataSize, &flagsOut); // not a web request, send a packet reporting number of received bytes
nixnax 69:23f560087c16 906 }
nixnax 69:23f560087c16 907 break;
nixnax 116:1272e9f7ad70 908 case TCP_FLAG_FIN:
nixnax 116:1272e9f7ad70 909 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 98:3babad0d1bd4 910 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 117:c819ae068336 911 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 128:e5958d143e9d 912 ack_out++; // for FIN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 913 break;
nixnax 77:abf92baebb42 914 default:
nixnax 69:23f560087c16 915 return; // ignore remaining packets
nixnax 93:9675adc36882 916 } // switch
nixnax 77:abf92baebb42 917
nixnax 69:23f560087c16 918 // The TCP flag handling is now done
nixnax 105:45001195b325 919 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 65:23b17c43aa0f 920 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 921 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 922 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 923 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 924 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 925 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 926 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 95:40af49390daf 927
nixnax 85:53e57ff1cf05 928 acktcp[0]=ack_out>>24;
nixnax 85:53e57ff1cf05 929 acktcp[1]=ack_out>>16;
nixnax 85:53e57ff1cf05 930 acktcp[2]=ack_out>>8;
nixnax 85:53e57ff1cf05 931 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 85:53e57ff1cf05 932 seqtcp[0]=seq_out>>24;
nixnax 85:53e57ff1cf05 933 seqtcp[1]=seq_out>>16;
nixnax 85:53e57ff1cf05 934 seqtcp[2]=seq_out>>8;
nixnax 85:53e57ff1cf05 935 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 936
nixnax 93:9675adc36882 937 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 93:9675adc36882 938
nixnax 114:8a5d70bbc1b2 939 // increment our outgoing ip packet counter
nixnax 114:8a5d70bbc1b2 940 ppp.ip.ident++; // get next ident number for our packet
nixnax 93:9675adc36882 941
nixnax 106:d14e6b597ca3 942 // Now we recalculate all the header sizes
nixnax 133:0f5b4085b6d3 943 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 133:0f5b4085b6d3 944 int newPacketSize = headerSizeIP + tcpSize; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 945 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 946 pktLen[1]=newPacketSize; // ip total packet size
nixnax 133:0f5b4085b6d3 947 ppp.pkt.len = newPacketSize+4+2; // ip packet length + 4-byte ppp prefix (ff 03 00 21) + 2 fcs (crc) bytes bytes at the end of the packet
nixnax 36:2a9b457f8276 948
nixnax 38:ab582987926e 949 // the header is all set up, now do the IP and TCP checksums
nixnax 61:b3c1a04efd0a 950 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 951 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 952 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 953
nixnax 64:677b9713a120 954 // 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 955 // 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 956 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 957 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 958 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 959 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 960 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 961 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 962 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 963
nixnax 61:b3c1a04efd0a 964 // pseudo-header built, now we can calculate TCP checksum
nixnax 29:30de79d658f6 965 checksumtcp[0]=0;
nixnax 29:30de79d658f6 966 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 967 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 968 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 969 checksumtcp[1]=pseudoHeaderSum;
nixnax 87:9f5ac1fabd95 970 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 114:8a5d70bbc1b2 971 dumpHeaderIP(1); // dump outgoing IP header
nixnax 114:8a5d70bbc1b2 972 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 124:18ef53f1d8b7 973 for (int i=0; i<70*1000/10; i++) { // 70 ms delay before sending frame - a typical internet delay time
nixnax 119:e14dd2bf0ea3 974 fillbuf(); // catch any incoming characters
nixnax 124:18ef53f1d8b7 975 wait_us(10); // wait less than 1 character duration at 115200
nixnax 119:e14dd2bf0ea3 976 }
nixnax 93:9675adc36882 977 send_pppFrame(); // All preparation complete - send the TCP response
nixnax 133:0f5b4085b6d3 978 if(0) dumpPPPFrame(); // set to 1 to dump transmitted ppp frame
nixnax 128:e5958d143e9d 979 memset(ppp.pkt.buf+44,0,500); // flush out traces of previous data that we may scan for
nixnax 29:30de79d658f6 980 }
nixnax 26:11f4eb2663a7 981
nixnax 29:30de79d658f6 982 void dumpDataTCP()
nixnax 29:30de79d658f6 983 {
nixnax 26:11f4eb2663a7 984 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 985 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 986 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 987 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 988 if (v1) {
nixnax 120:bef89e4c906e 989 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 990 fillbuf();
nixnax 120:bef89e4c906e 991 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 120:bef89e4c906e 992 fillbuf();
nixnax 125:ea88200b1df6 993 putsWhileCheckingInput( pbuf );
nixnax 29:30de79d658f6 994 }
nixnax 29:30de79d658f6 995 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 996 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 997 putsWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP ); // print the tcp payload data
nixnax 125:ea88200b1df6 998 putsWhileCheckingInput("\n");
nixnax 29:30de79d658f6 999 }
nixnax 29:30de79d658f6 1000 }
nixnax 26:11f4eb2663a7 1001
nixnax 29:30de79d658f6 1002 void TCPpacket()
nixnax 128:e5958d143e9d 1003 {
nixnax 114:8a5d70bbc1b2 1004 dumpHeaderIP(0); // dump incoming packet header
nixnax 114:8a5d70bbc1b2 1005 dumpHeaderTCP(0); // dump incoming packet header
nixnax 128:e5958d143e9d 1006 if (v2) dumpDataTCP();
nixnax 26:11f4eb2663a7 1007 tcpHandler();
nixnax 11:f58998c24f0b 1008 }
nixnax 11:f58998c24f0b 1009
nixnax 29:30de79d658f6 1010 void otherProtocol()
nixnax 29:30de79d658f6 1011 {
nixnax 119:e14dd2bf0ea3 1012 debugPrintf("Other IP protocol");
nixnax 29:30de79d658f6 1013 }
nixnax 26:11f4eb2663a7 1014
nixnax 29:30de79d658f6 1015 void IPframe()
nixnax 29:30de79d658f6 1016 {
nixnax 10:74f8233f72c0 1017 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 1018 switch (protocol) {
nixnax 29:30de79d658f6 1019 case 1:
nixnax 29:30de79d658f6 1020 ICMPpacket();
nixnax 29:30de79d658f6 1021 break;
nixnax 29:30de79d658f6 1022 case 2:
nixnax 29:30de79d658f6 1023 IGMPpacket();
nixnax 29:30de79d658f6 1024 break;
nixnax 29:30de79d658f6 1025 case 17:
nixnax 29:30de79d658f6 1026 UDPpacket();
nixnax 29:30de79d658f6 1027 break;
nixnax 29:30de79d658f6 1028 case 6:
nixnax 29:30de79d658f6 1029 TCPpacket();
nixnax 29:30de79d658f6 1030 break;
nixnax 29:30de79d658f6 1031 default:
nixnax 29:30de79d658f6 1032 otherProtocol();
nixnax 29:30de79d658f6 1033 }
nixnax 29:30de79d658f6 1034 }
nixnax 9:0992486d4a30 1035
nixnax 29:30de79d658f6 1036 void LCPconfReq()
nixnax 29:30de79d658f6 1037 {
nixnax 119:e14dd2bf0ea3 1038 debugPrintf("LCP Config ");
nixnax 9:0992486d4a30 1039 if (ppp.pkt.buf[7] != 4) {
nixnax 111:6a3b77c065c0 1040 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 119:e14dd2bf0ea3 1041 debugPrintf("Reject\n");
nixnax 93:9675adc36882 1042 send_pppFrame();
nixnax 9:0992486d4a30 1043 } else {
nixnax 9:0992486d4a30 1044 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 119:e14dd2bf0ea3 1045 debugPrintf("Ack\n");
nixnax 93:9675adc36882 1046 send_pppFrame();
nixnax 119:e14dd2bf0ea3 1047 debugPrintf("LCP Ask\n");
nixnax 11:f58998c24f0b 1048 ppp.pkt.buf[4]=1; // request no options
nixnax 93:9675adc36882 1049 send_pppFrame();
nixnax 9:0992486d4a30 1050 }
nixnax 9:0992486d4a30 1051 }
nixnax 9:0992486d4a30 1052
nixnax 29:30de79d658f6 1053 void LCPconfAck()
nixnax 29:30de79d658f6 1054 {
nixnax 119:e14dd2bf0ea3 1055 debugPrintf("LCP Ack\n");
nixnax 29:30de79d658f6 1056 }
nixnax 9:0992486d4a30 1057
nixnax 29:30de79d658f6 1058 void LCPend()
nixnax 29:30de79d658f6 1059 {
nixnax 29:30de79d658f6 1060 ppp.pkt.buf[4]=6;
nixnax 93:9675adc36882 1061 send_pppFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 1062 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 1063 pppInitStruct(); // flush the receive buffer
nixnax 119:e14dd2bf0ea3 1064 debugPrintf("LCP End\n");
nixnax 9:0992486d4a30 1065 }
nixnax 9:0992486d4a30 1066
nixnax 29:30de79d658f6 1067 void LCPother()
nixnax 29:30de79d658f6 1068 {
nixnax 119:e14dd2bf0ea3 1069 debugPrintf("LCP Other\n");
nixnax 95:40af49390daf 1070 dumpPPPFrame();
nixnax 29:30de79d658f6 1071 }
nixnax 29:30de79d658f6 1072
nixnax 29:30de79d658f6 1073 void LCPframe()
nixnax 29:30de79d658f6 1074 {
nixnax 29:30de79d658f6 1075 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 1076 switch (code) {
nixnax 29:30de79d658f6 1077 case 1:
nixnax 29:30de79d658f6 1078 LCPconfReq();
nixnax 29:30de79d658f6 1079 break; // config request
nixnax 29:30de79d658f6 1080 case 2:
nixnax 29:30de79d658f6 1081 LCPconfAck();
nixnax 29:30de79d658f6 1082 break; // config ack
nixnax 29:30de79d658f6 1083 case 5:
nixnax 29:30de79d658f6 1084 LCPend();
nixnax 29:30de79d658f6 1085 break; // end connection
nixnax 29:30de79d658f6 1086 default:
nixnax 29:30de79d658f6 1087 LCPother();
nixnax 29:30de79d658f6 1088 }
nixnax 9:0992486d4a30 1089 }
nixnax 9:0992486d4a30 1090
nixnax 29:30de79d658f6 1091 void discardedFrame()
nixnax 29:30de79d658f6 1092 {
nixnax 128:e5958d143e9d 1093 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 1094 }
nixnax 9:0992486d4a30 1095
nixnax 29:30de79d658f6 1096 void determinePacketType()
nixnax 29:30de79d658f6 1097 {
nixnax 29:30de79d658f6 1098 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 119:e14dd2bf0ea3 1099 debugPrintf("byte0 != ff\n");
nixnax 29:30de79d658f6 1100 return;
nixnax 29:30de79d658f6 1101 }
nixnax 29:30de79d658f6 1102 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 119:e14dd2bf0ea3 1103 debugPrintf("byte1 != 3\n");
nixnax 29:30de79d658f6 1104 return;
nixnax 29:30de79d658f6 1105 }
nixnax 29:30de79d658f6 1106 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 119:e14dd2bf0ea3 1107 debugPrintf("byte2 != 21\n");
nixnax 29:30de79d658f6 1108 return;
nixnax 29:30de79d658f6 1109 }
nixnax 9:0992486d4a30 1110 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 1111 switch (packetType) {
nixnax 29:30de79d658f6 1112 case 0xc0:
nixnax 29:30de79d658f6 1113 LCPframe();
nixnax 29:30de79d658f6 1114 break; // link control
nixnax 29:30de79d658f6 1115 case 0x80:
nixnax 29:30de79d658f6 1116 IPCPframe();
nixnax 29:30de79d658f6 1117 break; // IP control
nixnax 29:30de79d658f6 1118 case 0x00:
nixnax 29:30de79d658f6 1119 IPframe();
nixnax 29:30de79d658f6 1120 break; // IP itself
nixnax 29:30de79d658f6 1121 default:
nixnax 29:30de79d658f6 1122 discardedFrame();
nixnax 9:0992486d4a30 1123 }
nixnax 29:30de79d658f6 1124 }
nixnax 9:0992486d4a30 1125
nixnax 128:e5958d143e9d 1126 void wait_for_PPP_frame() // scan the PPP serial input stream for frame start markers
nixnax 50:ad4e7c3c88e5 1127 {
nixnax 85:53e57ff1cf05 1128 while(1) {
nixnax 93:9675adc36882 1129 fillbuf(); // handle received characters
nixnax 124:18ef53f1d8b7 1130 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 81:9ede60e9a2c8 1131 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 1132 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 1133 if (rx==FRAME_7E) {
nixnax 120:bef89e4c906e 1134 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 119:e14dd2bf0ea3 1135 ppp.firstFrame=0;
nixnax 128:e5958d143e9d 1136 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 120:bef89e4c906e 1137 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 119:e14dd2bf0ea3 1138 } else {
nixnax 119:e14dd2bf0ea3 1139 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 119:e14dd2bf0ea3 1140 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 128:e5958d143e9d 1141 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with the virtual tail
nixnax 128:e5958d143e9d 1142 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where next frame started
nixnax 119:e14dd2bf0ea3 1143 break;
nixnax 119:e14dd2bf0ea3 1144 }
nixnax 50:ad4e7c3c88e5 1145 }
nixnax 50:ad4e7c3c88e5 1146 }
nixnax 85:53e57ff1cf05 1147 }
nixnax 50:ad4e7c3c88e5 1148 }
nixnax 50:ad4e7c3c88e5 1149
nixnax 29:30de79d658f6 1150 void scanForConnectString()
nixnax 29:30de79d658f6 1151 {
nixnax 81:9ede60e9a2c8 1152 while(ppp.online == 0) {
nixnax 114:8a5d70bbc1b2 1153 fillbuf(); // gather received characters
nixnax 81:9ede60e9a2c8 1154 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 106:d14e6b597ca3 1155 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 107:5fe806713d49 1156 if (found1 != NULL) {
nixnax 107:5fe806713d49 1157 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 119:e14dd2bf0ea3 1158 if (v0) debugPrintf("Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 107:5fe806713d49 1159 pc.puts("CLIENTSERVER");
nixnax 120:bef89e4c906e 1160 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 119:e14dd2bf0ea3 1161 fillbuf();
nixnax 9:0992486d4a30 1162 }
nixnax 9:0992486d4a30 1163 }
nixnax 103:4f5512dd11cf 1164 }
nixnax 81:9ede60e9a2c8 1165
nixnax 0:2cf4880c312a 1166 int main()
nixnax 0:2cf4880c312a 1167 {
nixnax 128:e5958d143e9d 1168 pc.baud(115200); // USB serial port to pc
nixnax 128:e5958d143e9d 1169 debugBaudRate(115200); // baud rate for our (optional) debug port
nixnax 128:e5958d143e9d 1170 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 133:0f5b4085b6d3 1171
nixnax 9:0992486d4a30 1172 pppInitStruct(); // initialize all the PPP properties
nixnax 0:2cf4880c312a 1173 while(1) {
nixnax 128:e5958d143e9d 1174 scanForConnectString(); // wait for connect from PC dial-up networking
nixnax 81:9ede60e9a2c8 1175 while(ppp.online) {
nixnax 120:bef89e4c906e 1176 wait_for_PPP_frame(); // wait for a PPP frame
nixnax 81:9ede60e9a2c8 1177 }
nixnax 7:ab147f5e97ac 1178 }
nixnax 105:45001195b325 1179 }