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@120:bef89e4c906e, 2017-08-08 (annotated)

Committer:
nixnax
Date:
Tue Aug 08 18:36:38 2017 +0000
Revision:
120:bef89e4c906e
Parent:
119:e14dd2bf0ea3
Child:
121:705679672685
Fixed dropping characters when dumping debug data on second serial port

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 93:9675adc36882 3 // A Tiny 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 4:a469050d5b80 5
nixnax 93:9675adc36882 6 // Copyright 2016/2017 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax 81:9ede60e9a2c8 7
nixnax 41:e58a5a09f411 8 // Notes and Instructions
nixnax 41:e58a5a09f411 9 // http://bit.ly/PPP-Blinky-Instructions
nixnax 114:8a5d70bbc1b2 10 // http://bit.ly/win-rasdial-config
nixnax 0:2cf4880c312a 11
nixnax 41:e58a5a09f411 12 // Handy reading material
nixnax 6:fba4c2e817b8 13 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 14 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 39:b90183d35f1e 15 // http://bit.ly/dialup777error - how to solve Dial Up Error 777 in Windows 7/8/10
nixnax 41:e58a5a09f411 16 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 17
nixnax 29:30de79d658f6 18 // Handy tools
nixnax 44:d0c61ae49ea5 19 // 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 20 // https://www.microsoft.com/en-us/download/details.aspx?id=4865 - Microsoft network monitor - real-time monitoring of PPP packets
nixnax 29:30de79d658f6 21 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 95:40af49390daf 22 // 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 23 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 41:e58a5a09f411 24 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 91:5141ae9fba53 25 // 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 26
nixnax 92:cb962b365cce 27 // Connecting PPP-Blinky to Linux
nixnax 93:9675adc36882 28 // PPP-Blinky can be made to talk to Linux - tested on Fedora - the following command, which uses pppd, works:
nixnax 93:9675adc36882 29 // pppd /dev/ttyACM0 115200 debug dump local passive noccp novj nodetach nocrtscts 172.10.10.1:172.10.10.2
nixnax 92:cb962b365cce 30 // 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 31 // See also https://en.wikipedia.org/wiki/Point-to-Point_Protocol_daemon
nixnax 93:9675adc36882 32
nixnax 93:9675adc36882 33 // Ok, enough talking, time to check out some code!!
nixnax 106:d14e6b597ca3 34
nixnax 81:9ede60e9a2c8 35 #include "mbed.h"
nixnax 66:f005b9fdf4d1 36
nixnax 93:9675adc36882 37 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
nixnax 66:f005b9fdf4d1 38 // 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 39 // Note - the LPC11U24 does NOT have a second serial port
nixnax 120:bef89e4c906e 40 #define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax 0:2cf4880c312a 41
nixnax 93:9675adc36882 42 // here we define the OPTIONAL, second debug serial port for the various target boards
nixnax 93:9675adc36882 43 // 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 44 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 117:c819ae068336 45 #if defined(TARGET_LPC1768)
nixnax 117:c819ae068336 46 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 47 #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
nixnax 117:c819ae068336 48 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 49 #elif defined(TARGET_LPC11U24)
nixnax 117:c819ae068336 50 #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 118:54d1936e3768 51 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 118:54d1936e3768 52 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 53 #else
nixnax 117:c819ae068336 54 #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 55 #endif
nixnax 119:e14dd2bf0ea3 56 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we print debug messages */
nixnax 119:e14dd2bf0ea3 57 #define debugPutc(x...) xx.putc(x)
nixnax 118:54d1936e3768 58 #define debugBaudRate(x...) xx.baud(x)
nixnax 117:c819ae068336 59 #else
nixnax 119:e14dd2bf0ea3 60 // if we don't have a debug port the debug print functions do nothing
nixnax 119:e14dd2bf0ea3 61 #define debugPrintf(x...) {}
nixnax 119:e14dd2bf0ea3 62 #define debugPutc(x...) {}
nixnax 118:54d1936e3768 63 #define debugBaudRate(x...) {}
nixnax 41:e58a5a09f411 64 #endif
nixnax 41:e58a5a09f411 65
nixnax 110:baec959e1915 66 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 112:30172f36bd33 67 #define v0 1
nixnax 120:bef89e4c906e 68 #define v1 1
nixnax 77:abf92baebb42 69 #define v2 0
nixnax 114:8a5d70bbc1b2 70 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 114:8a5d70bbc1b2 71 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 29:30de79d658f6 72
nixnax 93:9675adc36882 73 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 93:9675adc36882 74 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 93:9675adc36882 75 const static char rootWebPage[] = "\
nixnax 66:f005b9fdf4d1 76 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 77 <html>\
nixnax 66:f005b9fdf4d1 78 <head>\
nixnax 66:f005b9fdf4d1 79 <title>mbed-PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 80 <script>\
nixnax 66:f005b9fdf4d1 81 window.onload=function(){\
nixnax 66:f005b9fdf4d1 82 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 66:f005b9fdf4d1 83 x().textContent = parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 84 </script>\
nixnax 66:f005b9fdf4d1 85 </head>\
nixnax 66:f005b9fdf4d1 86 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 87 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 88 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 89 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 90 </body>\
nixnax 69:23f560087c16 91 </html>"; // around 464 bytes long
nixnax 69:23f560087c16 92
nixnax 73:2f56ec87dbe9 93 // 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 94 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 72:ad3d12753acf 95 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 96 // See instructions at the top.
nixnax 73:2f56ec87dbe9 97 // 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 98 Serial pc(USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax 29:30de79d658f6 99
nixnax 29:30de79d658f6 100 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 101
nixnax 66:f005b9fdf4d1 102 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 103 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 104
nixnax 29:30de79d658f6 105 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 106 struct pppType {
nixnax 38:ab582987926e 107 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 108 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 109 int ledState; // state of LED1
nixnax 98:3babad0d1bd4 110 int httpPageCount;
nixnax 119:e14dd2bf0ea3 111 int firstFrame; // cleared after first frame
nixnax 4:a469050d5b80 112 struct {
nixnax 105:45001195b325 113 #define RXBUFLEN (1<<11)
nixnax 117:c819ae068336 114 // the serial port receive buffer and packet buffer, size is RXBUFLEN (currently 2048 bytes)
nixnax 85:53e57ff1cf05 115 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in ring buffer
nixnax 93:9675adc36882 116 int head;
nixnax 93:9675adc36882 117 int tail;
nixnax 95:40af49390daf 118 int rtail;
nixnax 93:9675adc36882 119 int buflevel;
nixnax 38:ab582987926e 120 } rx; // serial port objects
nixnax 4:a469050d5b80 121 struct {
nixnax 38:ab582987926e 122 int len; // number of bytes in buffer
nixnax 38:ab582987926e 123 int crc; // PPP CRC (frame check)
nixnax 77:abf92baebb42 124 #define TCP_max_size 3300
nixnax 77:abf92baebb42 125 char buf[TCP_max_size]; // send and receive buffer large enough for unstuffed (decoded) hdlc frames
nixnax 38:ab582987926e 126 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 127 struct {
nixnax 50:ad4e7c3c88e5 128 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 129 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 130 } hdlc; // hdlc frame objects
nixnax 114:8a5d70bbc1b2 131 struct {
nixnax 114:8a5d70bbc1b2 132 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 114:8a5d70bbc1b2 133 } ip; // ip related object
nixnax 29:30de79d658f6 134 };
nixnax 31:e000c1b9c565 135
nixnax 29:30de79d658f6 136 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 137
nixnax 93:9675adc36882 138 // Initialize our global structure, clear the buffer, etc.
nixnax 29:30de79d658f6 139 void pppInitStruct()
nixnax 29:30de79d658f6 140 {
nixnax 81:9ede60e9a2c8 141 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 29:30de79d658f6 142 ppp.online=0;
nixnax 29:30de79d658f6 143 ppp.rx.tail=0;
nixnax 93:9675adc36882 144 ppp.rx.rtail=0;
nixnax 29:30de79d658f6 145 ppp.rx.head=0;
nixnax 81:9ede60e9a2c8 146 ppp.rx.buflevel=0;
nixnax 29:30de79d658f6 147 ppp.pkt.len=0;
nixnax 114:8a5d70bbc1b2 148 ppp.ip.ident=10000; // easy to recognize in ip packet dumps
nixnax 29:30de79d658f6 149 ppp.ledState=0;
nixnax 81:9ede60e9a2c8 150 ppp.hdlc.frameStartIndex=0;
nixnax 98:3babad0d1bd4 151 ppp.httpPageCount=0;
nixnax 119:e14dd2bf0ea3 152 ppp.firstFrame=1;
nixnax 29:30de79d658f6 153 }
nixnax 26:11f4eb2663a7 154
nixnax 43:aa57db08995d 155 void led1Toggle()
nixnax 43:aa57db08995d 156 {
nixnax 43:aa57db08995d 157 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 93:9675adc36882 158 led1 = ppp.ledState; // toggle led
nixnax 43:aa57db08995d 159 }
nixnax 43:aa57db08995d 160
nixnax 85:53e57ff1cf05 161 // fill our own receive buffer with characters from the PPP serial port
nixnax 85:53e57ff1cf05 162 void fillbuf()
nixnax 0:2cf4880c312a 163 {
nixnax 107:5fe806713d49 164 char ch;
nixnax 85:53e57ff1cf05 165 if ( pc.readable() ) {
nixnax 85:53e57ff1cf05 166 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 93:9675adc36882 167 if ( hd == ppp.rx.rtail ) {
nixnax 119:e14dd2bf0ea3 168 debugPrintf("\nReceive buffer full\n");
nixnax 85:53e57ff1cf05 169 return;
nixnax 83:cdcb81d1910f 170 }
nixnax 107:5fe806713d49 171 ch = pc.getc(); // read new character
nixnax 107:5fe806713d49 172 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 107:5fe806713d49 173 if ( ppp.online == 0 ) {
nixnax 107:5fe806713d49 174 if (ch == 0x7E) {
nixnax 107:5fe806713d49 175 ppp.online = 1;
nixnax 114:8a5d70bbc1b2 176 }
nixnax 114:8a5d70bbc1b2 177 }
nixnax 20:5db9b77b38a6 178 ppp.rx.head = hd; // update head pointer
nixnax 81:9ede60e9a2c8 179 ppp.rx.buflevel++;
nixnax 15:b0154c910143 180 }
nixnax 0:2cf4880c312a 181 }
nixnax 0:2cf4880c312a 182
nixnax 118:54d1936e3768 183 // print to debug port while checking for incoming characters
nixnax 119:e14dd2bf0ea3 184 void putcWhileCheckingInput( char outByte )
nixnax 119:e14dd2bf0ea3 185 {
nixnax 119:e14dd2bf0ea3 186 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 119:e14dd2bf0ea3 187 fillbuf();
nixnax 119:e14dd2bf0ea3 188 debugPutc( outByte );
nixnax 119:e14dd2bf0ea3 189 fillbuf();
nixnax 119:e14dd2bf0ea3 190 #endif
nixnax 119:e14dd2bf0ea3 191 }
nixnax 119:e14dd2bf0ea3 192
nixnax 118:54d1936e3768 193 void printWhileCheckingInput( char * data )
nixnax 118:54d1936e3768 194 {
nixnax 118:54d1936e3768 195 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 118:54d1936e3768 196 char * nextChar = data;
nixnax 118:54d1936e3768 197 while( *nextChar != 0 ) {
nixnax 119:e14dd2bf0ea3 198 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 118:54d1936e3768 199 nextChar++;
nixnax 118:54d1936e3768 200 }
nixnax 118:54d1936e3768 201 #endif
nixnax 118:54d1936e3768 202 }
nixnax 118:54d1936e3768 203
nixnax 118:54d1936e3768 204 void crcReset()
nixnax 118:54d1936e3768 205 {
nixnax 118:54d1936e3768 206 ppp.crc=0xffff; // crc restart
nixnax 118:54d1936e3768 207 }
nixnax 118:54d1936e3768 208
nixnax 118:54d1936e3768 209 void crcDo(int x) // cumulative crc
nixnax 118:54d1936e3768 210 {
nixnax 118:54d1936e3768 211 for (int i=0; i<8; i++) {
nixnax 118:54d1936e3768 212 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 118:54d1936e3768 213 x>>=1;
nixnax 118:54d1936e3768 214 }
nixnax 118:54d1936e3768 215 // fillbuf();
nixnax 118:54d1936e3768 216 }
nixnax 118:54d1936e3768 217
nixnax 118:54d1936e3768 218 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 118:54d1936e3768 219 {
nixnax 118:54d1936e3768 220 crcReset();
nixnax 118:54d1936e3768 221 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 118:54d1936e3768 222 return ppp.crc;
nixnax 118:54d1936e3768 223 }
nixnax 118:54d1936e3768 224
nixnax 85:53e57ff1cf05 225 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 226 {
nixnax 43:aa57db08995d 227 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 43:aa57db08995d 228 return emptyStatus;
nixnax 0:2cf4880c312a 229 }
nixnax 0:2cf4880c312a 230
nixnax 85:53e57ff1cf05 231 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 232 {
nixnax 63:9253b0e1b7d8 233 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 81:9ede60e9a2c8 234 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 81:9ede60e9a2c8 235 ppp.rx.buflevel--;
nixnax 63:9253b0e1b7d8 236 return x;
nixnax 0:2cf4880c312a 237 }
nixnax 0:2cf4880c312a 238
nixnax 95:40af49390daf 239 // Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 95:40af49390daf 240 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 95:40af49390daf 241 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 95:40af49390daf 242 void dumpPPPFrame()
nixnax 95:40af49390daf 243 {
nixnax 120:bef89e4c906e 244 char pbuf[30];
nixnax 120:bef89e4c906e 245 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 120:bef89e4c906e 246 fillbuf();
nixnax 120:bef89e4c906e 247 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 120:bef89e4c906e 248 fillbuf();
nixnax 120:bef89e4c906e 249 printWhileCheckingInput(pbuf);
nixnax 120:bef89e4c906e 250 }
nixnax 120:bef89e4c906e 251 fillbuf();
nixnax 120:bef89e4c906e 252 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 120:bef89e4c906e 253 fillbuf();
nixnax 120:bef89e4c906e 254 printWhileCheckingInput(pbuf);
nixnax 95:40af49390daf 255 }
nixnax 95:40af49390daf 256
nixnax 119:e14dd2bf0ea3 257 void processPPPFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 258 {
nixnax 38:ab582987926e 259 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 260 if(start==end) {
nixnax 111:6a3b77c065c0 261 return; // empty frame
nixnax 29:30de79d658f6 262 }
nixnax 9:0992486d4a30 263 crcReset();
nixnax 9:0992486d4a30 264 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 265 ppp.pkt.len=0;
nixnax 9:0992486d4a30 266 int unstuff=0;
nixnax 17:4918c893d802 267 int idx = start;
nixnax 17:4918c893d802 268 while(1) {
nixnax 9:0992486d4a30 269 if (unstuff==0) {
nixnax 72:ad3d12753acf 270 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 271 else {
nixnax 72:ad3d12753acf 272 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 273 ppp.pkt.len++;
nixnax 29:30de79d658f6 274 dest++;
nixnax 72:ad3d12753acf 275 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 276 }
nixnax 66:f005b9fdf4d1 277 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 278 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 279 ppp.pkt.len++;
nixnax 29:30de79d658f6 280 dest++;
nixnax 72:ad3d12753acf 281 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 282 unstuff=0;
nixnax 9:0992486d4a30 283 }
nixnax 81:9ede60e9a2c8 284 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 285 if (idx == end) break;
nixnax 9:0992486d4a30 286 }
nixnax 29:30de79d658f6 287 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 120:bef89e4c906e 288 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 9:0992486d4a30 289 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 290 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 291 determinePacketType();
nixnax 90:55e0f243a7ce 292 } else {
nixnax 120:bef89e4c906e 293 if (0) { // set to 1 to report FCS errors
nixnax 118:54d1936e3768 294 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 295 fillbuf();
nixnax 119:e14dd2bf0ea3 296 sprintf(pbuf, "PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 120:bef89e4c906e 297 fillbuf();
nixnax 118:54d1936e3768 298 printWhileCheckingInput( pbuf );
nixnax 120:bef89e4c906e 299 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 95:40af49390daf 300 }
nixnax 9:0992486d4a30 301 }
nixnax 9:0992486d4a30 302 }
nixnax 9:0992486d4a30 303
nixnax 29:30de79d658f6 304 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 305 {
nixnax 29:30de79d658f6 306 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 119:e14dd2bf0ea3 307 fillbuf();
nixnax 29:30de79d658f6 308 pc.putc(0x7d);
nixnax 119:e14dd2bf0ea3 309 fillbuf();
nixnax 66:f005b9fdf4d1 310 pc.putc(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 311 } else {
nixnax 119:e14dd2bf0ea3 312 fillbuf();
nixnax 29:30de79d658f6 313 pc.putc(ch);
nixnax 29:30de79d658f6 314 }
nixnax 11:f58998c24f0b 315 }
nixnax 9:0992486d4a30 316
nixnax 93:9675adc36882 317 void send_pppFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 318 {
nixnax 17:4918c893d802 319 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 320 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 321 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 322 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 95:40af49390daf 323 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 93:9675adc36882 324 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 93:9675adc36882 325 }
nixnax 16:cb0b80c24ba2 326 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 327 }
nixnax 9:0992486d4a30 328
nixnax 93:9675adc36882 329 void ipcpConfigRequestHandler()
nixnax 29:30de79d658f6 330 {
nixnax 119:e14dd2bf0ea3 331 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 92:cb962b365cce 332 ppp.pkt.buf[4]=2; // change code to ack
nixnax 108:f77ec4605945 333 send_pppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 106:d14e6b597ca3 334
nixnax 119:e14dd2bf0ea3 335 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 92:cb962b365cce 336 ppp.pkt.buf[4]=1; // change code to request
nixnax 106:d14e6b597ca3 337 ppp.pkt.buf[7]=4; // no options in this request
nixnax 106:d14e6b597ca3 338 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 103:4f5512dd11cf 339 send_pppFrame(); // send our request
nixnax 9:0992486d4a30 340 }
nixnax 9:0992486d4a30 341
nixnax 93:9675adc36882 342 void ipcpAckHandler()
nixnax 29:30de79d658f6 343 {
nixnax 119:e14dd2bf0ea3 344 debugPrintf("Their IPCP Grant\n");
nixnax 29:30de79d658f6 345 }
nixnax 9:0992486d4a30 346
nixnax 93:9675adc36882 347 void ipcpNackHandler()
nixnax 29:30de79d658f6 348 {
nixnax 119:e14dd2bf0ea3 349 debugPrintf("Their IPCP Nack, Our ACK\n");
nixnax 107:5fe806713d49 350 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 106:d14e6b597ca3 351 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 106:d14e6b597ca3 352 send_pppFrame(); // let's request this IP address as ours
nixnax 106:d14e6b597ca3 353 } // if it's not an IP nack we ignore it
nixnax 29:30de79d658f6 354 }
nixnax 9:0992486d4a30 355
nixnax 93:9675adc36882 356 void ipcpDefaultHandler()
nixnax 29:30de79d658f6 357 {
nixnax 119:e14dd2bf0ea3 358 debugPrintf("Their IPCP Other\n");
nixnax 29:30de79d658f6 359 }
nixnax 29:30de79d658f6 360
nixnax 29:30de79d658f6 361 void IPCPframe()
nixnax 29:30de79d658f6 362 {
nixnax 9:0992486d4a30 363 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 364 switch (code) {
nixnax 29:30de79d658f6 365 case 1:
nixnax 93:9675adc36882 366 ipcpConfigRequestHandler();
nixnax 29:30de79d658f6 367 break;
nixnax 29:30de79d658f6 368 case 2:
nixnax 93:9675adc36882 369 ipcpAckHandler();
nixnax 29:30de79d658f6 370 break;
nixnax 29:30de79d658f6 371 case 3:
nixnax 93:9675adc36882 372 ipcpNackHandler();
nixnax 29:30de79d658f6 373 break;
nixnax 29:30de79d658f6 374 default:
nixnax 93:9675adc36882 375 ipcpDefaultHandler();
nixnax 9:0992486d4a30 376 }
nixnax 29:30de79d658f6 377 }
nixnax 9:0992486d4a30 378
nixnax 29:30de79d658f6 379 void UDPpacket()
nixnax 29:30de79d658f6 380 {
nixnax 12:db0dc91f0231 381 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 382 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 383 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 118:54d1936e3768 384 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 385 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 386 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 387 #endif
nixnax 12:db0dc91f0231 388 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 389 char * udpInf = udpBlock+8; // actual start of info
nixnax 118:54d1936e3768 390 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 391 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 392 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 393 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 394 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 395 #endif
nixnax 29:30de79d658f6 396 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 397 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 119:e14dd2bf0ea3 398 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 119:e14dd2bf0ea3 399 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 119:e14dd2bf0ea3 400 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 29:30de79d658f6 401 int printSize = udpLength;
nixnax 29:30de79d658f6 402 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 403 if (v1) {
nixnax 29:30de79d658f6 404 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 405 char ch = udpInf[i];
nixnax 29:30de79d658f6 406 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 407 debugPrintf("%c", ch);
nixnax 29:30de79d658f6 408 } else {
nixnax 119:e14dd2bf0ea3 409 debugPrintf("_");
nixnax 29:30de79d658f6 410 }
nixnax 29:30de79d658f6 411 }
nixnax 29:30de79d658f6 412 }
nixnax 119:e14dd2bf0ea3 413 if (v0) debugPrintf("\n");
nixnax 12:db0dc91f0231 414 }
nixnax 11:f58998c24f0b 415
nixnax 76:00e208cceb8b 416 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 417 {
nixnax 75:0d513869231f 418 unsigned int sum=0;
nixnax 76:00e208cceb8b 419 unsigned char placeHolder;
nixnax 29:30de79d658f6 420 if (len&1) {
nixnax 76:00e208cceb8b 421 placeHolder = ptr[len]; // when length is odd stuff in a zero byte
nixnax 76:00e208cceb8b 422 ptr[len]=0;
nixnax 29:30de79d658f6 423 }
nixnax 29:30de79d658f6 424 for (int i=0; i<len/2; i++) {
nixnax 76:00e208cceb8b 425 unsigned int hi = *ptr;
nixnax 29:30de79d658f6 426 ptr++;
nixnax 76:00e208cceb8b 427 unsigned int lo = *ptr;
nixnax 29:30de79d658f6 428 ptr++;
nixnax 76:00e208cceb8b 429 unsigned int val = ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 430 sum = sum + val;
nixnax 11:f58998c24f0b 431 }
nixnax 29:30de79d658f6 432 if (len&1) {
nixnax 76:00e208cceb8b 433 ptr[len] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 434 }
nixnax 76:00e208cceb8b 435 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 436 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 437 return ~sum;
nixnax 29:30de79d658f6 438 }
nixnax 11:f58998c24f0b 439
nixnax 29:30de79d658f6 440 void headerCheckSum()
nixnax 29:30de79d658f6 441 {
nixnax 11:f58998c24f0b 442 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 443 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 444 int sum=0;
nixnax 11:f58998c24f0b 445
nixnax 29:30de79d658f6 446 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 447 int hi = *ptr;
nixnax 29:30de79d658f6 448 ptr++;
nixnax 29:30de79d658f6 449 int lo = *ptr;
nixnax 29:30de79d658f6 450 ptr++;
nixnax 11:f58998c24f0b 451 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 452 sum = sum + val;
nixnax 11:f58998c24f0b 453 }
nixnax 11:f58998c24f0b 454 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 455 sum = ~sum;
nixnax 11:f58998c24f0b 456 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 457 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 458 }
nixnax 9:0992486d4a30 459
nixnax 29:30de79d658f6 460 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 461 {
nixnax 12:db0dc91f0231 462 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 463 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 464 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 465 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 466 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 467 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 468 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 469 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 470 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 471 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 472 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 473 char * dstAdr = ipPkt+16;
nixnax 63:9253b0e1b7d8 474 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 475 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 476 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 63:9253b0e1b7d8 477 #endif
nixnax 119:e14dd2bf0ea3 478 if(v0) debugPrintf("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 119:e14dd2bf0ea3 479 if(v0) debugPrintf("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 480 char src[4];
nixnax 29:30de79d658f6 481 char dst[4];
nixnax 12:db0dc91f0231 482 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 483 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 484 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 485 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 486 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 487 chkSum[0]=0;
nixnax 29:30de79d658f6 488 chkSum[1]=0;
nixnax 12:db0dc91f0231 489 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 490 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 491 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 492 icmpSum[0]=0;
nixnax 29:30de79d658f6 493 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 494 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 495 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 496 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 497 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 498
nixnax 16:cb0b80c24ba2 499 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 500 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 501 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 502 if (v0) {
nixnax 29:30de79d658f6 503 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 504 char ch = icmpData[i];
nixnax 29:30de79d658f6 505 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 506 debugPrintf("%c",ch);
nixnax 29:30de79d658f6 507 } else {
nixnax 119:e14dd2bf0ea3 508 debugPrintf("_");
nixnax 29:30de79d658f6 509 }
nixnax 29:30de79d658f6 510 }
nixnax 119:e14dd2bf0ea3 511 debugPrintf("\n");
nixnax 29:30de79d658f6 512 }
nixnax 93:9675adc36882 513 send_pppFrame(); // reply to the ping
nixnax 29:30de79d658f6 514
nixnax 12:db0dc91f0231 515 } else {
nixnax 29:30de79d658f6 516 if (v0) {
nixnax 119:e14dd2bf0ea3 517 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 518 }
nixnax 11:f58998c24f0b 519 }
nixnax 11:f58998c24f0b 520 }
nixnax 11:f58998c24f0b 521
nixnax 29:30de79d658f6 522 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 523 {
nixnax 119:e14dd2bf0ea3 524 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 525 }
nixnax 11:f58998c24f0b 526
nixnax 114:8a5d70bbc1b2 527 void dumpHeaderIP (int outGoing)
nixnax 29:30de79d658f6 528 {
nixnax 114:8a5d70bbc1b2 529 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 119:e14dd2bf0ea3 530 fillbuf(); // we are expecting the first character of the next packet
nixnax 114:8a5d70bbc1b2 531 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 114:8a5d70bbc1b2 532 char * ident = ipPkt+4; // 2 bytes
nixnax 118:54d1936e3768 533 #ifdef UNUSED_IP_VARIABLES
nixnax 114:8a5d70bbc1b2 534 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 114:8a5d70bbc1b2 535 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 114:8a5d70bbc1b2 536 char * version = ipPkt; // top 4 bits
nixnax 114:8a5d70bbc1b2 537 char * ihl = ipPkt; // bottom 4 bits
nixnax 114:8a5d70bbc1b2 538 char * dscp = ipPkt+1; // top 6 bits
nixnax 114:8a5d70bbc1b2 539 char * ecn = ipPkt+1; // lower 2 bits
nixnax 114:8a5d70bbc1b2 540 char * pktLen = ipPkt+2; // 2 bytes
nixnax 114:8a5d70bbc1b2 541 char * flags = ipPkt+6; // 2 bits
nixnax 114:8a5d70bbc1b2 542 char * ttl = ipPkt+8; // 1 byte
nixnax 114:8a5d70bbc1b2 543 char * protocol = ipPkt+9; // 1 byte
nixnax 114:8a5d70bbc1b2 544 char * headercheck= ipPkt+10; // 2 bytes
nixnax 114:8a5d70bbc1b2 545 int versionIP = (version[0]>>4)&0xf;
nixnax 114:8a5d70bbc1b2 546 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 114:8a5d70bbc1b2 547 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 114:8a5d70bbc1b2 548 int ecnIP = ecn[0]&3;
nixnax 114:8a5d70bbc1b2 549 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 114:8a5d70bbc1b2 550 int flagsIP = flags[0]>>14&3;
nixnax 114:8a5d70bbc1b2 551 int ttlIP = ttl[0];
nixnax 114:8a5d70bbc1b2 552 int protocolIP = protocol[0];
nixnax 114:8a5d70bbc1b2 553 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 554 #endif
nixnax 119:e14dd2bf0ea3 555 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 119:e14dd2bf0ea3 556 char pbuf[50]; // local print buffer
nixnax 118:54d1936e3768 557 int n=0;
nixnax 119:e14dd2bf0ea3 558 fillbuf(); // we are expecting the first character of the next packet
nixnax 119:e14dd2bf0ea3 559 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 119:e14dd2bf0ea3 560 fillbuf(); // we are expecting the first character of the next packet
nixnax 119:e14dd2bf0ea3 561 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 562 fillbuf(); // we are expecting the first character of the next packet
nixnax 119:e14dd2bf0ea3 563 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 564 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 565 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 119:e14dd2bf0ea3 566 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 119:e14dd2bf0ea3 567 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 568 #endif
nixnax 118:54d1936e3768 569 printWhileCheckingInput( pbuf );
nixnax 114:8a5d70bbc1b2 570 #ifndef TCP_HEADER_DUMP_YES
nixnax 119:e14dd2bf0ea3 571 printWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 114:8a5d70bbc1b2 572 #endif
nixnax 114:8a5d70bbc1b2 573 #endif
nixnax 29:30de79d658f6 574 }
nixnax 26:11f4eb2663a7 575
nixnax 114:8a5d70bbc1b2 576 void dumpHeaderTCP(int outGoing)
nixnax 29:30de79d658f6 577 {
nixnax 114:8a5d70bbc1b2 578 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 114:8a5d70bbc1b2 579 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 114:8a5d70bbc1b2 580 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 114:8a5d70bbc1b2 581 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 114:8a5d70bbc1b2 582 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 114:8a5d70bbc1b2 583 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 114:8a5d70bbc1b2 584 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 114:8a5d70bbc1b2 585 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 114:8a5d70bbc1b2 586 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 114:8a5d70bbc1b2 587 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 588
nixnax 119:e14dd2bf0ea3 589 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 119:e14dd2bf0ea3 590 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 119:e14dd2bf0ea3 591 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 114:8a5d70bbc1b2 592 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 114:8a5d70bbc1b2 593 flagInfo[8]=0; // null terminate string
nixnax 114:8a5d70bbc1b2 594 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 114:8a5d70bbc1b2 595 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 114:8a5d70bbc1b2 596 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 114:8a5d70bbc1b2 597 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 114:8a5d70bbc1b2 598 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 114:8a5d70bbc1b2 599 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 114:8a5d70bbc1b2 600 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 114:8a5d70bbc1b2 601 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 118:54d1936e3768 602 #else
nixnax 119:e14dd2bf0ea3 603 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 119:e14dd2bf0ea3 604 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 119:e14dd2bf0ea3 605 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 119:e14dd2bf0ea3 606 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 119:e14dd2bf0ea3 607 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 119:e14dd2bf0ea3 608 flagInfo[1]=' ';
nixnax 119:e14dd2bf0ea3 609 flagInfo[2]=0;
nixnax 118:54d1936e3768 610 #endif
nixnax 119:e14dd2bf0ea3 611 printWhileCheckingInput( flagInfo );
nixnax 119:e14dd2bf0ea3 612 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 613 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 614 putcWhileCheckingInput('\n'); // write a newline after every packet
nixnax 119:e14dd2bf0ea3 615 #endif
nixnax 119:e14dd2bf0ea3 616 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 119:e14dd2bf0ea3 617 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 118:54d1936e3768 618 }
nixnax 114:8a5d70bbc1b2 619 #endif
nixnax 29:30de79d658f6 620 }
nixnax 29:30de79d658f6 621
nixnax 68:0b74763ae67f 622 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 623 {
nixnax 67:a63e3486bcda 624 int n=0; // number of bytes we have printed so far
nixnax 77:abf92baebb42 625 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 626 int contentLengthStart; // index where HTML starts
nixnax 93:9675adc36882 627 int xFetch, httpGetRoot; // temporary storage of strncmp results
nixnax 85:53e57ff1cf05 628
nixnax 98:3babad0d1bd4 629 ppp.httpPageCount++; // increment the number of frames we have made
nixnax 85:53e57ff1cf05 630
nixnax 98:3babad0d1bd4 631 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found GET, respond to both HTTP/1.<anything>
nixnax 99:3f56162e703e 632 xFetch = strncmp(dataStart, "GET /x", 6); // found GET /x , respond to both HTTP/1.<anything>
nixnax 119:e14dd2bf0ea3 633 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 93:9675adc36882 634 if( (httpGetRoot==0) || (xFetch==0) ) {
nixnax 115:b8ddff0e782f 635 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky\r\n"); // 200 OK header
nixnax 83:cdcb81d1910f 636 } else {
nixnax 89:2c8dd0c2a426 637 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 83:cdcb81d1910f 638 }
nixnax 83:cdcb81d1910f 639 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 640 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 641 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 642 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 643 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 644 nHeader=n; // size of HTTP header
nixnax 93:9675adc36882 645 if( httpGetRoot == 0 ) {
nixnax 83:cdcb81d1910f 646 // this is where we insert our web page into the buffer
nixnax 93:9675adc36882 647 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 93:9675adc36882 648 n = n + sizeof(rootWebPage);
nixnax 85:53e57ff1cf05 649 } else {
nixnax 109:644a59ebb5b1 650 if (xFetch == 0) { // the page request started with "GET /x"
nixnax 89:2c8dd0c2a426 651
nixnax 89:2c8dd0c2a426 652 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 89:2c8dd0c2a426 653 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 89:2c8dd0c2a426 654 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 106:d14e6b597ca3 655 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed-ppp-blinky</title>"); // html title (W3C.org required elements)
nixnax 98:3babad0d1bd4 656 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.httpPageCount); // body = the http frame count
nixnax 89:2c8dd0c2a426 657 #else
nixnax 109:644a59ebb5b1 658 #define BENCHMARK_USING_BROWSER_NO /* set to _YES if you want to use your browser as a benchmark tool */
nixnax 98:3babad0d1bd4 659 #ifndef BENCHMARK_USING_BROWSER_NO
nixnax 119:e14dd2bf0ea3 660 // 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 661 n=n+sprintf(n+dataStart, "<script>setTimeout(function(){location.reload();},10);</script><body>%d</body>",ppp.httpPageCount);
nixnax 98:3babad0d1bd4 662 #else
nixnax 98:3babad0d1bd4 663 n=n+sprintf(n+dataStart,"%d",ppp.httpPageCount); // not valid html but fast, most browsers and curl are ok with it
nixnax 98:3babad0d1bd4 664 #endif
nixnax 89:2c8dd0c2a426 665 #endif
nixnax 89:2c8dd0c2a426 666
nixnax 89:2c8dd0c2a426 667 } else {
nixnax 89:2c8dd0c2a426 668 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 89:2c8dd0c2a426 669 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>ppp-blinky-mbed</title>"); // html title (required element)
nixnax 89:2c8dd0c2a426 670 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 89:2c8dd0c2a426 671 }
nixnax 83:cdcb81d1910f 672 }
nixnax 87:9f5ac1fabd95 673 while( (n%4)!= 2) n=n+sprintf(n+dataStart," "); // insert spaces until n is exactly two away from a multiple of four
nixnax 87:9f5ac1fabd95 674 n=n+sprintf(n+dataStart,"\r\n"); // add the last two characters (\r\n) - n is now an exact multiple of four
nixnax 87:9f5ac1fabd95 675
nixnax 83:cdcb81d1910f 676 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 677 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 678 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 679 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 680
nixnax 77:abf92baebb42 681 if (v2) {
nixnax 120:bef89e4c906e 682 // debugPrintf("HTTP Response: HTTP-header %d HTTP-content %d HTTP-total %d\n",nHeader,n-nHeader,n);
nixnax 77:abf92baebb42 683 }
nixnax 67:a63e3486bcda 684 return n; // total byte size of our response
nixnax 67:a63e3486bcda 685 }
nixnax 67:a63e3486bcda 686
nixnax 98:3babad0d1bd4 687 // if not an http response we just report the number of bytes received
nixnax 98:3babad0d1bd4 688 // this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 98:3babad0d1bd4 689 int tcpResponse(char * dataStart, int len)
nixnax 98:3babad0d1bd4 690 {
nixnax 98:3babad0d1bd4 691 int n=0; // number of bytes we have printed so far
nixnax 98:3babad0d1bd4 692 n=n+sprintf(n+dataStart,"Got %04d bytes.\n",len); // report the number of bytes received
nixnax 98:3babad0d1bd4 693 while( (n%4)!= 0) n=n+sprintf(n+dataStart,"*"); // insert spaces until n is exactly two away from a multiple of four
nixnax 98:3babad0d1bd4 694 if (v2) {
nixnax 120:bef89e4c906e 695 // debugPrintf("TCP response %d bytes\n",n);
nixnax 98:3babad0d1bd4 696 }
nixnax 98:3babad0d1bd4 697 return n; // total byte size of our response
nixnax 98:3babad0d1bd4 698 }
nixnax 98:3babad0d1bd4 699
nixnax 29:30de79d658f6 700 void tcpHandler()
nixnax 29:30de79d658f6 701 {
nixnax 87:9f5ac1fabd95 702 // IP header
nixnax 119:e14dd2bf0ea3 703
nixnax 26:11f4eb2663a7 704 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 705 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 706 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 707 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 708 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 709 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 710 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 711 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 712 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 713 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 714
nixnax 87:9f5ac1fabd95 715 // TCP header
nixnax 87:9f5ac1fabd95 716
nixnax 87:9f5ac1fabd95 717 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 87:9f5ac1fabd95 718 char * srctcp = tcp + 0; // 2 bytes
nixnax 87:9f5ac1fabd95 719 char * dsttcp = tcp + 2; // 2 bytes
nixnax 87:9f5ac1fabd95 720 char * seqtcp = tcp + 4; // 4 bytes
nixnax 87:9f5ac1fabd95 721 char * acktcp = tcp + 8; // 4 bytes
nixnax 87:9f5ac1fabd95 722 char * offset = tcp + 12; // 4 bits
nixnax 87:9f5ac1fabd95 723 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 87:9f5ac1fabd95 724 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 87:9f5ac1fabd95 725 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 26:11f4eb2663a7 726
nixnax 26:11f4eb2663a7 727 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 728 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 729 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 730
nixnax 87:9f5ac1fabd95 731 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 732 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 87:9f5ac1fabd95 733 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 81:9ede60e9a2c8 734
nixnax 85:53e57ff1cf05 735 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 85:53e57ff1cf05 736 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 85:53e57ff1cf05 737
nixnax 85:53e57ff1cf05 738 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 87:9f5ac1fabd95 739 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 81:9ede60e9a2c8 740
nixnax 29:30de79d658f6 741 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 742 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 743 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 744 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 745 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 746
nixnax 87:9f5ac1fabd95 747 // first we shorten the TCP response header to only 20 bytes.
nixnax 87:9f5ac1fabd95 748 // this means we ignore all TCP option requests
nixnax 87:9f5ac1fabd95 749
nixnax 87:9f5ac1fabd95 750 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 87:9f5ac1fabd95 751 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 87:9f5ac1fabd95 752 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 87:9f5ac1fabd95 753 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 754 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 755 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 756
nixnax 35:e7068df4d971 757 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 758 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 87:9f5ac1fabd95 759 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 92:cb962b365cce 760
nixnax 119:e14dd2bf0ea3 761 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 119:e14dd2bf0ea3 762 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 38:ab582987926e 763
nixnax 106:d14e6b597ca3 764 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 77:abf92baebb42 765
nixnax 69:23f560087c16 766 switch ( flagsTCP ) {
nixnax 69:23f560087c16 767 case TCP_FLAG_SYN:
nixnax 87:9f5ac1fabd95 768 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 119:e14dd2bf0ea3 769 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 85:53e57ff1cf05 770 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 771 break;
nixnax 77:abf92baebb42 772 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 98:3babad0d1bd4 773 if ( strncmp(tcpDataIn, "GET /", 5) == 0) { // check for an http GET command
nixnax 118:54d1936e3768 774 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN | TCP_FLAG_PSH; // set outgoing FIN flag to ask them to close from their side
nixnax 87:9f5ac1fabd95 775 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 98:3babad0d1bd4 776 } else {
nixnax 106:d14e6b597ca3 777 dataLen = tcpResponse(tcpDataOut,tcpDataSize); // not a web request, send a packet reporting number of received bytes
nixnax 69:23f560087c16 778 }
nixnax 69:23f560087c16 779 break;
nixnax 116:1272e9f7ad70 780 case TCP_FLAG_FIN:
nixnax 116:1272e9f7ad70 781 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 98:3babad0d1bd4 782 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 117:c819ae068336 783 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 85:53e57ff1cf05 784 ack_out++; // for FIN flag we always have to increase sequence by 1
nixnax 69:23f560087c16 785 break;
nixnax 77:abf92baebb42 786 default:
nixnax 69:23f560087c16 787 return; // ignore remaining packets
nixnax 93:9675adc36882 788 } // switch
nixnax 77:abf92baebb42 789
nixnax 69:23f560087c16 790 // The TCP flag handling is now done
nixnax 105:45001195b325 791 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 95:40af49390daf 792
nixnax 65:23b17c43aa0f 793 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 794 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 795 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 796 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 797
nixnax 60:2b770949c911 798 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 799 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 800 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 95:40af49390daf 801
nixnax 85:53e57ff1cf05 802 acktcp[0]=ack_out>>24;
nixnax 85:53e57ff1cf05 803 acktcp[1]=ack_out>>16;
nixnax 85:53e57ff1cf05 804 acktcp[2]=ack_out>>8;
nixnax 85:53e57ff1cf05 805 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 38:ab582987926e 806
nixnax 85:53e57ff1cf05 807 seqtcp[0]=seq_out>>24;
nixnax 85:53e57ff1cf05 808 seqtcp[1]=seq_out>>16;
nixnax 85:53e57ff1cf05 809 seqtcp[2]=seq_out>>8;
nixnax 85:53e57ff1cf05 810 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 811
nixnax 93:9675adc36882 812 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 93:9675adc36882 813
nixnax 114:8a5d70bbc1b2 814 // increment our outgoing ip packet counter
nixnax 114:8a5d70bbc1b2 815 ppp.ip.ident++; // get next ident number for our packet
nixnax 114:8a5d70bbc1b2 816 ident[0] = ppp.ip.ident>>8;
nixnax 114:8a5d70bbc1b2 817 ident[1] = ppp.ip.ident>>0; // insert OUR ident
nixnax 93:9675adc36882 818
nixnax 106:d14e6b597ca3 819 // Now we recalculate all the header sizes
nixnax 38:ab582987926e 820 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 821 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 822 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 823 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 824 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 825
nixnax 38:ab582987926e 826 // the header is all set up, now do the IP and TCP checksums
nixnax 61:b3c1a04efd0a 827 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 828 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 829 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 830
nixnax 64:677b9713a120 831 // 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 832 // this header contains the most important parts of the IP header, i.e. source and destination address, protocol number and data length.
nixnax 63:9253b0e1b7d8 833
nixnax 87:9f5ac1fabd95 834 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 835 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 836 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 837 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 838 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 839 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 840 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 841
nixnax 61:b3c1a04efd0a 842 // pseudo-header built, now we can calculate TCP checksum
nixnax 29:30de79d658f6 843 checksumtcp[0]=0;
nixnax 29:30de79d658f6 844 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 845 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 846 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 847 checksumtcp[1]=pseudoHeaderSum;
nixnax 87:9f5ac1fabd95 848 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 114:8a5d70bbc1b2 849 dumpHeaderIP(1); // dump outgoing IP header
nixnax 114:8a5d70bbc1b2 850 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 120:bef89e4c906e 851 for (int i=0; i<60000/50; i++) { // a 60 ms delay before sending frame - typical internet delay time
nixnax 119:e14dd2bf0ea3 852 fillbuf(); // catch any incoming characters
nixnax 119:e14dd2bf0ea3 853 wait_us(50); // wait less than 1 character duration at 115200
nixnax 119:e14dd2bf0ea3 854 }
nixnax 93:9675adc36882 855 send_pppFrame(); // All preparation complete - send the TCP response
nixnax 29:30de79d658f6 856 }
nixnax 26:11f4eb2663a7 857
nixnax 29:30de79d658f6 858 void dumpDataTCP()
nixnax 29:30de79d658f6 859 {
nixnax 26:11f4eb2663a7 860 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 861 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 862 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 863 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 864 if (v1) {
nixnax 120:bef89e4c906e 865 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 866 fillbuf();
nixnax 120:bef89e4c906e 867 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 120:bef89e4c906e 868 fillbuf();
nixnax 120:bef89e4c906e 869 printWhileCheckingInput( pbuf );
nixnax 29:30de79d658f6 870 }
nixnax 29:30de79d658f6 871 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 872 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 120:bef89e4c906e 873 printWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP ); // print the tcp payload data
nixnax 120:bef89e4c906e 874 printWhileCheckingInput("\n");
nixnax 29:30de79d658f6 875 }
nixnax 29:30de79d658f6 876 }
nixnax 26:11f4eb2663a7 877
nixnax 29:30de79d658f6 878 void TCPpacket()
nixnax 29:30de79d658f6 879 {
nixnax 114:8a5d70bbc1b2 880 dumpHeaderIP(0); // dump incoming packet header
nixnax 114:8a5d70bbc1b2 881 dumpHeaderTCP(0); // dump incoming packet header
nixnax 77:abf92baebb42 882 if (v2) {
nixnax 77:abf92baebb42 883 dumpDataTCP();
nixnax 77:abf92baebb42 884 }
nixnax 26:11f4eb2663a7 885 tcpHandler();
nixnax 11:f58998c24f0b 886 }
nixnax 11:f58998c24f0b 887
nixnax 29:30de79d658f6 888 void otherProtocol()
nixnax 29:30de79d658f6 889 {
nixnax 119:e14dd2bf0ea3 890 debugPrintf("Other IP protocol");
nixnax 29:30de79d658f6 891 }
nixnax 26:11f4eb2663a7 892
nixnax 29:30de79d658f6 893 void IPframe()
nixnax 29:30de79d658f6 894 {
nixnax 10:74f8233f72c0 895 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 896 switch (protocol) {
nixnax 29:30de79d658f6 897 case 1:
nixnax 29:30de79d658f6 898 ICMPpacket();
nixnax 29:30de79d658f6 899 break;
nixnax 29:30de79d658f6 900 case 2:
nixnax 29:30de79d658f6 901 IGMPpacket();
nixnax 29:30de79d658f6 902 break;
nixnax 29:30de79d658f6 903 case 17:
nixnax 29:30de79d658f6 904 UDPpacket();
nixnax 29:30de79d658f6 905 break;
nixnax 29:30de79d658f6 906 case 6:
nixnax 29:30de79d658f6 907 TCPpacket();
nixnax 29:30de79d658f6 908 break;
nixnax 29:30de79d658f6 909 default:
nixnax 29:30de79d658f6 910 otherProtocol();
nixnax 29:30de79d658f6 911 }
nixnax 29:30de79d658f6 912 }
nixnax 9:0992486d4a30 913
nixnax 29:30de79d658f6 914 void LCPconfReq()
nixnax 29:30de79d658f6 915 {
nixnax 119:e14dd2bf0ea3 916 debugPrintf("LCP Config ");
nixnax 9:0992486d4a30 917 if (ppp.pkt.buf[7] != 4) {
nixnax 111:6a3b77c065c0 918 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 119:e14dd2bf0ea3 919 debugPrintf("Reject\n");
nixnax 93:9675adc36882 920 send_pppFrame();
nixnax 9:0992486d4a30 921 } else {
nixnax 9:0992486d4a30 922 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 119:e14dd2bf0ea3 923 debugPrintf("Ack\n");
nixnax 93:9675adc36882 924 send_pppFrame();
nixnax 119:e14dd2bf0ea3 925 debugPrintf("LCP Ask\n");
nixnax 11:f58998c24f0b 926 ppp.pkt.buf[4]=1; // request no options
nixnax 93:9675adc36882 927 send_pppFrame();
nixnax 9:0992486d4a30 928 }
nixnax 9:0992486d4a30 929 }
nixnax 9:0992486d4a30 930
nixnax 29:30de79d658f6 931 void LCPconfAck()
nixnax 29:30de79d658f6 932 {
nixnax 119:e14dd2bf0ea3 933 debugPrintf("LCP Ack\n");
nixnax 29:30de79d658f6 934 }
nixnax 9:0992486d4a30 935
nixnax 29:30de79d658f6 936 void LCPend()
nixnax 29:30de79d658f6 937 {
nixnax 29:30de79d658f6 938 ppp.pkt.buf[4]=6;
nixnax 93:9675adc36882 939 send_pppFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 940 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 941 pppInitStruct(); // flush the receive buffer
nixnax 119:e14dd2bf0ea3 942 debugPrintf("LCP End\n");
nixnax 9:0992486d4a30 943 }
nixnax 9:0992486d4a30 944
nixnax 29:30de79d658f6 945 void LCPother()
nixnax 29:30de79d658f6 946 {
nixnax 119:e14dd2bf0ea3 947 debugPrintf("LCP Other\n");
nixnax 95:40af49390daf 948 dumpPPPFrame();
nixnax 29:30de79d658f6 949 }
nixnax 29:30de79d658f6 950
nixnax 29:30de79d658f6 951 void LCPframe()
nixnax 29:30de79d658f6 952 {
nixnax 29:30de79d658f6 953 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 954 switch (code) {
nixnax 29:30de79d658f6 955 case 1:
nixnax 29:30de79d658f6 956 LCPconfReq();
nixnax 29:30de79d658f6 957 break; // config request
nixnax 29:30de79d658f6 958 case 2:
nixnax 29:30de79d658f6 959 LCPconfAck();
nixnax 29:30de79d658f6 960 break; // config ack
nixnax 29:30de79d658f6 961 case 5:
nixnax 29:30de79d658f6 962 LCPend();
nixnax 29:30de79d658f6 963 break; // end connection
nixnax 29:30de79d658f6 964 default:
nixnax 29:30de79d658f6 965 LCPother();
nixnax 29:30de79d658f6 966 }
nixnax 9:0992486d4a30 967 }
nixnax 9:0992486d4a30 968
nixnax 29:30de79d658f6 969 void discardedFrame()
nixnax 29:30de79d658f6 970 {
nixnax 29:30de79d658f6 971 if (v0) {
nixnax 119:e14dd2bf0ea3 972 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 29:30de79d658f6 973 }
nixnax 9:0992486d4a30 974 }
nixnax 9:0992486d4a30 975
nixnax 29:30de79d658f6 976 void determinePacketType()
nixnax 29:30de79d658f6 977 {
nixnax 29:30de79d658f6 978 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 119:e14dd2bf0ea3 979 debugPrintf("byte0 != ff\n");
nixnax 29:30de79d658f6 980 return;
nixnax 29:30de79d658f6 981 }
nixnax 29:30de79d658f6 982 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 119:e14dd2bf0ea3 983 debugPrintf("byte1 != 3\n");
nixnax 29:30de79d658f6 984 return;
nixnax 29:30de79d658f6 985 }
nixnax 29:30de79d658f6 986 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 119:e14dd2bf0ea3 987 debugPrintf("byte2 != 21\n");
nixnax 29:30de79d658f6 988 return;
nixnax 29:30de79d658f6 989 }
nixnax 9:0992486d4a30 990 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 991 switch (packetType) {
nixnax 29:30de79d658f6 992 case 0xc0:
nixnax 29:30de79d658f6 993 LCPframe();
nixnax 29:30de79d658f6 994 break; // link control
nixnax 29:30de79d658f6 995 case 0x80:
nixnax 29:30de79d658f6 996 IPCPframe();
nixnax 29:30de79d658f6 997 break; // IP control
nixnax 29:30de79d658f6 998 case 0x00:
nixnax 29:30de79d658f6 999 IPframe();
nixnax 29:30de79d658f6 1000 break; // IP itself
nixnax 29:30de79d658f6 1001 default:
nixnax 29:30de79d658f6 1002 discardedFrame();
nixnax 9:0992486d4a30 1003 }
nixnax 29:30de79d658f6 1004 }
nixnax 9:0992486d4a30 1005
nixnax 119:e14dd2bf0ea3 1006 void wait_for_PPP_frame()
nixnax 50:ad4e7c3c88e5 1007 {
nixnax 85:53e57ff1cf05 1008 while(1) {
nixnax 93:9675adc36882 1009 fillbuf(); // handle received characters
nixnax 81:9ede60e9a2c8 1010 if ( rxbufNotEmpty() ) {
nixnax 81:9ede60e9a2c8 1011 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 1012 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 1013 if (rx==FRAME_7E) {
nixnax 120:bef89e4c906e 1014 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 119:e14dd2bf0ea3 1015 ppp.firstFrame=0;
nixnax 120:bef89e4c906e 1016 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with virtual tail
nixnax 120:bef89e4c906e 1017 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 119:e14dd2bf0ea3 1018 } else {
nixnax 119:e14dd2bf0ea3 1019 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 119:e14dd2bf0ea3 1020 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 120:bef89e4c906e 1021 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with virtual tail
nixnax 119:e14dd2bf0ea3 1022 ppp.hdlc.frameStartIndex = ppp.rx.tail; // where next frame will start
nixnax 119:e14dd2bf0ea3 1023 break;
nixnax 119:e14dd2bf0ea3 1024 }
nixnax 50:ad4e7c3c88e5 1025 }
nixnax 50:ad4e7c3c88e5 1026 }
nixnax 85:53e57ff1cf05 1027 }
nixnax 50:ad4e7c3c88e5 1028 }
nixnax 50:ad4e7c3c88e5 1029
nixnax 29:30de79d658f6 1030 void scanForConnectString()
nixnax 29:30de79d658f6 1031 {
nixnax 81:9ede60e9a2c8 1032 while(ppp.online == 0) {
nixnax 114:8a5d70bbc1b2 1033 fillbuf(); // gather received characters
nixnax 81:9ede60e9a2c8 1034 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 106:d14e6b597ca3 1035 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 107:5fe806713d49 1036 if (found1 != NULL) {
nixnax 107:5fe806713d49 1037 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 119:e14dd2bf0ea3 1038 if (v0) debugPrintf("Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 107:5fe806713d49 1039 pc.puts("CLIENTSERVER");
nixnax 120:bef89e4c906e 1040 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 119:e14dd2bf0ea3 1041 fillbuf();
nixnax 9:0992486d4a30 1042 }
nixnax 9:0992486d4a30 1043 }
nixnax 103:4f5512dd11cf 1044 }
nixnax 81:9ede60e9a2c8 1045
nixnax 0:2cf4880c312a 1046 int main()
nixnax 0:2cf4880c312a 1047 {
nixnax 120:bef89e4c906e 1048 pc.baud(115200); // USB serial port
nixnax 120:bef89e4c906e 1049 debugBaudRate(115200); // baud rate for our debug port - if we have one
nixnax 120:bef89e4c906e 1050 debugPrintf("\x1b[2J\x1b[H\x1b[30mPPP-Blinky Ready.\n"); // VT100 codes for clear_screen, home, black_text - Tera Term is a handy VT100 terminal
nixnax 9:0992486d4a30 1051 pppInitStruct(); // initialize all the PPP properties
nixnax 0:2cf4880c312a 1052 while(1) {
nixnax 120:bef89e4c906e 1053 scanForConnectString(); // wait for connect
nixnax 81:9ede60e9a2c8 1054 while(ppp.online) {
nixnax 120:bef89e4c906e 1055 wait_for_PPP_frame(); // wait for a PPP frame
nixnax 81:9ede60e9a2c8 1056 }
nixnax 7:ab147f5e97ac 1057 }
nixnax 105:45001195b325 1058 }