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@119:e14dd2bf0ea3, 2017-08-08 (annotated)

Committer:
nixnax
Date:
Tue Aug 08 17:10:29 2017 +0000
Revision:
119:e14dd2bf0ea3
Parent:
118:54d1936e3768
Child:
120:bef89e4c906e
Fix dropping of input characters, first packet error.

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 119:e14dd2bf0ea3 40 #define SERIAL_PORT_MONITOR_YES /* 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 81:9ede60e9a2c8 68 #define v1 0
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 119:e14dd2bf0ea3 176 debugPrintf("HDLC Frame (0x7E)\n");
nixnax 114:8a5d70bbc1b2 177 }
nixnax 114:8a5d70bbc1b2 178 }
nixnax 20:5db9b77b38a6 179 ppp.rx.head = hd; // update head pointer
nixnax 81:9ede60e9a2c8 180 ppp.rx.buflevel++;
nixnax 15:b0154c910143 181 }
nixnax 0:2cf4880c312a 182 }
nixnax 0:2cf4880c312a 183
nixnax 118:54d1936e3768 184 // print to debug port while checking for incoming characters
nixnax 119:e14dd2bf0ea3 185 void putcWhileCheckingInput( char outByte )
nixnax 119:e14dd2bf0ea3 186 {
nixnax 119:e14dd2bf0ea3 187 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 119:e14dd2bf0ea3 188 fillbuf();
nixnax 119:e14dd2bf0ea3 189 debugPutc( outByte );
nixnax 119:e14dd2bf0ea3 190 fillbuf();
nixnax 119:e14dd2bf0ea3 191 #endif
nixnax 119:e14dd2bf0ea3 192 }
nixnax 119:e14dd2bf0ea3 193
nixnax 118:54d1936e3768 194 void printWhileCheckingInput( char * data )
nixnax 118:54d1936e3768 195 {
nixnax 118:54d1936e3768 196 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 118:54d1936e3768 197 char * nextChar = data;
nixnax 118:54d1936e3768 198 while( *nextChar != 0 ) {
nixnax 119:e14dd2bf0ea3 199 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 118:54d1936e3768 200 nextChar++;
nixnax 118:54d1936e3768 201 }
nixnax 118:54d1936e3768 202 #endif
nixnax 118:54d1936e3768 203 }
nixnax 118:54d1936e3768 204
nixnax 118:54d1936e3768 205 void crcReset()
nixnax 118:54d1936e3768 206 {
nixnax 118:54d1936e3768 207 ppp.crc=0xffff; // crc restart
nixnax 118:54d1936e3768 208 }
nixnax 118:54d1936e3768 209
nixnax 118:54d1936e3768 210 void crcDo(int x) // cumulative crc
nixnax 118:54d1936e3768 211 {
nixnax 118:54d1936e3768 212 for (int i=0; i<8; i++) {
nixnax 118:54d1936e3768 213 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 118:54d1936e3768 214 x>>=1;
nixnax 118:54d1936e3768 215 }
nixnax 118:54d1936e3768 216 // fillbuf();
nixnax 118:54d1936e3768 217 }
nixnax 118:54d1936e3768 218
nixnax 118:54d1936e3768 219 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 118:54d1936e3768 220 {
nixnax 118:54d1936e3768 221 crcReset();
nixnax 118:54d1936e3768 222 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 118:54d1936e3768 223 return ppp.crc;
nixnax 118:54d1936e3768 224 }
nixnax 118:54d1936e3768 225
nixnax 85:53e57ff1cf05 226 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 227 {
nixnax 43:aa57db08995d 228 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 43:aa57db08995d 229 return emptyStatus;
nixnax 0:2cf4880c312a 230 }
nixnax 0:2cf4880c312a 231
nixnax 85:53e57ff1cf05 232 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 233 {
nixnax 63:9253b0e1b7d8 234 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 81:9ede60e9a2c8 235 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 81:9ede60e9a2c8 236 ppp.rx.buflevel--;
nixnax 63:9253b0e1b7d8 237 return x;
nixnax 0:2cf4880c312a 238 }
nixnax 0:2cf4880c312a 239
nixnax 95:40af49390daf 240 // Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 95:40af49390daf 241 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 95:40af49390daf 242 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 95:40af49390daf 243 void dumpPPPFrame()
nixnax 95:40af49390daf 244 {
nixnax 119:e14dd2bf0ea3 245 for(int i=0; i<ppp.pkt.len; i++) debugPrintf("%02x ", ppp.pkt.buf[i]);
nixnax 119:e14dd2bf0ea3 246 debugPrintf(" CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 95:40af49390daf 247 }
nixnax 95:40af49390daf 248
nixnax 119:e14dd2bf0ea3 249 void processPPPFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 250 {
nixnax 38:ab582987926e 251 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 252 if(start==end) {
nixnax 111:6a3b77c065c0 253 return; // empty frame
nixnax 29:30de79d658f6 254 }
nixnax 9:0992486d4a30 255 crcReset();
nixnax 9:0992486d4a30 256 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 257 ppp.pkt.len=0;
nixnax 9:0992486d4a30 258 int unstuff=0;
nixnax 17:4918c893d802 259 int idx = start;
nixnax 17:4918c893d802 260 while(1) {
nixnax 9:0992486d4a30 261 if (unstuff==0) {
nixnax 72:ad3d12753acf 262 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 263 else {
nixnax 72:ad3d12753acf 264 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 265 ppp.pkt.len++;
nixnax 29:30de79d658f6 266 dest++;
nixnax 72:ad3d12753acf 267 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 268 }
nixnax 66:f005b9fdf4d1 269 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 270 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 271 ppp.pkt.len++;
nixnax 29:30de79d658f6 272 dest++;
nixnax 72:ad3d12753acf 273 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 274 unstuff=0;
nixnax 9:0992486d4a30 275 }
nixnax 81:9ede60e9a2c8 276 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 277 if (idx == end) break;
nixnax 9:0992486d4a30 278 }
nixnax 29:30de79d658f6 279 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 280 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 281 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 282 determinePacketType();
nixnax 90:55e0f243a7ce 283 } else {
nixnax 118:54d1936e3768 284 if (1) {
nixnax 118:54d1936e3768 285 char pbuf[50]; // local print buffer
nixnax 119:e14dd2bf0ea3 286 sprintf(pbuf, "PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 118:54d1936e3768 287 printWhileCheckingInput( pbuf );
nixnax 118:54d1936e3768 288 if(0) dumpPPPFrame();
nixnax 95:40af49390daf 289 }
nixnax 9:0992486d4a30 290 }
nixnax 9:0992486d4a30 291 }
nixnax 9:0992486d4a30 292
nixnax 29:30de79d658f6 293 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 294 {
nixnax 29:30de79d658f6 295 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 119:e14dd2bf0ea3 296 fillbuf();
nixnax 29:30de79d658f6 297 pc.putc(0x7d);
nixnax 119:e14dd2bf0ea3 298 fillbuf();
nixnax 66:f005b9fdf4d1 299 pc.putc(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 300 } else {
nixnax 119:e14dd2bf0ea3 301 fillbuf();
nixnax 29:30de79d658f6 302 pc.putc(ch);
nixnax 29:30de79d658f6 303 }
nixnax 11:f58998c24f0b 304 }
nixnax 9:0992486d4a30 305
nixnax 93:9675adc36882 306 void send_pppFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 307 {
nixnax 17:4918c893d802 308 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 309 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 310 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 311 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 95:40af49390daf 312 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 93:9675adc36882 313 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 93:9675adc36882 314 }
nixnax 16:cb0b80c24ba2 315 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 316 }
nixnax 9:0992486d4a30 317
nixnax 93:9675adc36882 318 void ipcpConfigRequestHandler()
nixnax 29:30de79d658f6 319 {
nixnax 119:e14dd2bf0ea3 320 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 92:cb962b365cce 321 ppp.pkt.buf[4]=2; // change code to ack
nixnax 108:f77ec4605945 322 send_pppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 106:d14e6b597ca3 323
nixnax 119:e14dd2bf0ea3 324 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 92:cb962b365cce 325 ppp.pkt.buf[4]=1; // change code to request
nixnax 106:d14e6b597ca3 326 ppp.pkt.buf[7]=4; // no options in this request
nixnax 106:d14e6b597ca3 327 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 103:4f5512dd11cf 328 send_pppFrame(); // send our request
nixnax 9:0992486d4a30 329 }
nixnax 9:0992486d4a30 330
nixnax 93:9675adc36882 331 void ipcpAckHandler()
nixnax 29:30de79d658f6 332 {
nixnax 119:e14dd2bf0ea3 333 debugPrintf("Their IPCP Grant\n");
nixnax 29:30de79d658f6 334 }
nixnax 9:0992486d4a30 335
nixnax 93:9675adc36882 336 void ipcpNackHandler()
nixnax 29:30de79d658f6 337 {
nixnax 119:e14dd2bf0ea3 338 debugPrintf("Their IPCP Nack, Our ACK\n");
nixnax 107:5fe806713d49 339 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 106:d14e6b597ca3 340 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 106:d14e6b597ca3 341 send_pppFrame(); // let's request this IP address as ours
nixnax 106:d14e6b597ca3 342 } // if it's not an IP nack we ignore it
nixnax 29:30de79d658f6 343 }
nixnax 9:0992486d4a30 344
nixnax 93:9675adc36882 345 void ipcpDefaultHandler()
nixnax 29:30de79d658f6 346 {
nixnax 119:e14dd2bf0ea3 347 debugPrintf("Their IPCP Other\n");
nixnax 29:30de79d658f6 348 }
nixnax 29:30de79d658f6 349
nixnax 29:30de79d658f6 350 void IPCPframe()
nixnax 29:30de79d658f6 351 {
nixnax 9:0992486d4a30 352 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 353 switch (code) {
nixnax 29:30de79d658f6 354 case 1:
nixnax 93:9675adc36882 355 ipcpConfigRequestHandler();
nixnax 29:30de79d658f6 356 break;
nixnax 29:30de79d658f6 357 case 2:
nixnax 93:9675adc36882 358 ipcpAckHandler();
nixnax 29:30de79d658f6 359 break;
nixnax 29:30de79d658f6 360 case 3:
nixnax 93:9675adc36882 361 ipcpNackHandler();
nixnax 29:30de79d658f6 362 break;
nixnax 29:30de79d658f6 363 default:
nixnax 93:9675adc36882 364 ipcpDefaultHandler();
nixnax 9:0992486d4a30 365 }
nixnax 29:30de79d658f6 366 }
nixnax 9:0992486d4a30 367
nixnax 29:30de79d658f6 368 void UDPpacket()
nixnax 29:30de79d658f6 369 {
nixnax 12:db0dc91f0231 370 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 371 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 372 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 118:54d1936e3768 373 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 374 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 375 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 376 #endif
nixnax 12:db0dc91f0231 377 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 378 char * udpInf = udpBlock+8; // actual start of info
nixnax 118:54d1936e3768 379 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 380 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 381 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 382 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 383 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 384 #endif
nixnax 29:30de79d658f6 385 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 386 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 119:e14dd2bf0ea3 387 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 119:e14dd2bf0ea3 388 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 119:e14dd2bf0ea3 389 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 29:30de79d658f6 390 int printSize = udpLength;
nixnax 29:30de79d658f6 391 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 392 if (v1) {
nixnax 29:30de79d658f6 393 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 394 char ch = udpInf[i];
nixnax 29:30de79d658f6 395 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 396 debugPrintf("%c", ch);
nixnax 29:30de79d658f6 397 } else {
nixnax 119:e14dd2bf0ea3 398 debugPrintf("_");
nixnax 29:30de79d658f6 399 }
nixnax 29:30de79d658f6 400 }
nixnax 29:30de79d658f6 401 }
nixnax 119:e14dd2bf0ea3 402 if (v0) debugPrintf("\n");
nixnax 12:db0dc91f0231 403 }
nixnax 11:f58998c24f0b 404
nixnax 76:00e208cceb8b 405 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 406 {
nixnax 75:0d513869231f 407 unsigned int sum=0;
nixnax 76:00e208cceb8b 408 unsigned char placeHolder;
nixnax 29:30de79d658f6 409 if (len&1) {
nixnax 76:00e208cceb8b 410 placeHolder = ptr[len]; // when length is odd stuff in a zero byte
nixnax 76:00e208cceb8b 411 ptr[len]=0;
nixnax 29:30de79d658f6 412 }
nixnax 29:30de79d658f6 413 for (int i=0; i<len/2; i++) {
nixnax 76:00e208cceb8b 414 unsigned int hi = *ptr;
nixnax 29:30de79d658f6 415 ptr++;
nixnax 76:00e208cceb8b 416 unsigned int lo = *ptr;
nixnax 29:30de79d658f6 417 ptr++;
nixnax 76:00e208cceb8b 418 unsigned int val = ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 419 sum = sum + val;
nixnax 11:f58998c24f0b 420 }
nixnax 29:30de79d658f6 421 if (len&1) {
nixnax 76:00e208cceb8b 422 ptr[len] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 423 }
nixnax 76:00e208cceb8b 424 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 425 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 426 return ~sum;
nixnax 29:30de79d658f6 427 }
nixnax 11:f58998c24f0b 428
nixnax 29:30de79d658f6 429 void headerCheckSum()
nixnax 29:30de79d658f6 430 {
nixnax 11:f58998c24f0b 431 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 432 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 433 int sum=0;
nixnax 11:f58998c24f0b 434
nixnax 29:30de79d658f6 435 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 436 int hi = *ptr;
nixnax 29:30de79d658f6 437 ptr++;
nixnax 29:30de79d658f6 438 int lo = *ptr;
nixnax 29:30de79d658f6 439 ptr++;
nixnax 11:f58998c24f0b 440 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 441 sum = sum + val;
nixnax 11:f58998c24f0b 442 }
nixnax 11:f58998c24f0b 443 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 444 sum = ~sum;
nixnax 11:f58998c24f0b 445 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 446 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 447 }
nixnax 9:0992486d4a30 448
nixnax 29:30de79d658f6 449 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 450 {
nixnax 12:db0dc91f0231 451 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 452 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 453 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 454 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 455 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 456 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 457 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 458 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 459 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 460 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 461 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 462 char * dstAdr = ipPkt+16;
nixnax 63:9253b0e1b7d8 463 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 464 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 465 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 63:9253b0e1b7d8 466 #endif
nixnax 119:e14dd2bf0ea3 467 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 468 if(v0) debugPrintf("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 469 char src[4];
nixnax 29:30de79d658f6 470 char dst[4];
nixnax 12:db0dc91f0231 471 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 472 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 473 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 474 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 475 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 476 chkSum[0]=0;
nixnax 29:30de79d658f6 477 chkSum[1]=0;
nixnax 12:db0dc91f0231 478 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 479 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 480 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 481 icmpSum[0]=0;
nixnax 29:30de79d658f6 482 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 483 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 484 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 485 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 486 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 487
nixnax 16:cb0b80c24ba2 488 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 489 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 490 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 491 if (v0) {
nixnax 29:30de79d658f6 492 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 493 char ch = icmpData[i];
nixnax 29:30de79d658f6 494 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 495 debugPrintf("%c",ch);
nixnax 29:30de79d658f6 496 } else {
nixnax 119:e14dd2bf0ea3 497 debugPrintf("_");
nixnax 29:30de79d658f6 498 }
nixnax 29:30de79d658f6 499 }
nixnax 119:e14dd2bf0ea3 500 debugPrintf("\n");
nixnax 29:30de79d658f6 501 }
nixnax 93:9675adc36882 502 send_pppFrame(); // reply to the ping
nixnax 29:30de79d658f6 503
nixnax 12:db0dc91f0231 504 } else {
nixnax 29:30de79d658f6 505 if (v0) {
nixnax 119:e14dd2bf0ea3 506 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 507 }
nixnax 11:f58998c24f0b 508 }
nixnax 11:f58998c24f0b 509 }
nixnax 11:f58998c24f0b 510
nixnax 29:30de79d658f6 511 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 512 {
nixnax 119:e14dd2bf0ea3 513 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 514 }
nixnax 11:f58998c24f0b 515
nixnax 114:8a5d70bbc1b2 516 void dumpHeaderIP (int outGoing)
nixnax 29:30de79d658f6 517 {
nixnax 114:8a5d70bbc1b2 518 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 119:e14dd2bf0ea3 519 fillbuf(); // we are expecting the first character of the next packet
nixnax 114:8a5d70bbc1b2 520 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 114:8a5d70bbc1b2 521 char * ident = ipPkt+4; // 2 bytes
nixnax 118:54d1936e3768 522 #ifdef UNUSED_IP_VARIABLES
nixnax 114:8a5d70bbc1b2 523 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 114:8a5d70bbc1b2 524 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 114:8a5d70bbc1b2 525 char * version = ipPkt; // top 4 bits
nixnax 114:8a5d70bbc1b2 526 char * ihl = ipPkt; // bottom 4 bits
nixnax 114:8a5d70bbc1b2 527 char * dscp = ipPkt+1; // top 6 bits
nixnax 114:8a5d70bbc1b2 528 char * ecn = ipPkt+1; // lower 2 bits
nixnax 114:8a5d70bbc1b2 529 char * pktLen = ipPkt+2; // 2 bytes
nixnax 114:8a5d70bbc1b2 530 char * flags = ipPkt+6; // 2 bits
nixnax 114:8a5d70bbc1b2 531 char * ttl = ipPkt+8; // 1 byte
nixnax 114:8a5d70bbc1b2 532 char * protocol = ipPkt+9; // 1 byte
nixnax 114:8a5d70bbc1b2 533 char * headercheck= ipPkt+10; // 2 bytes
nixnax 114:8a5d70bbc1b2 534 int versionIP = (version[0]>>4)&0xf;
nixnax 114:8a5d70bbc1b2 535 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 114:8a5d70bbc1b2 536 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 114:8a5d70bbc1b2 537 int ecnIP = ecn[0]&3;
nixnax 114:8a5d70bbc1b2 538 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 114:8a5d70bbc1b2 539 int flagsIP = flags[0]>>14&3;
nixnax 114:8a5d70bbc1b2 540 int ttlIP = ttl[0];
nixnax 114:8a5d70bbc1b2 541 int protocolIP = protocol[0];
nixnax 114:8a5d70bbc1b2 542 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 543 #endif
nixnax 119:e14dd2bf0ea3 544 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 119:e14dd2bf0ea3 545 char pbuf[50]; // local print buffer
nixnax 118:54d1936e3768 546 int n=0;
nixnax 119:e14dd2bf0ea3 547 fillbuf(); // we are expecting the first character of the next packet
nixnax 119:e14dd2bf0ea3 548 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 119:e14dd2bf0ea3 549 fillbuf(); // we are expecting the first character of the next packet
nixnax 119:e14dd2bf0ea3 550 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 551 fillbuf(); // we are expecting the first character of the next packet
nixnax 119:e14dd2bf0ea3 552 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 553 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 554 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 119:e14dd2bf0ea3 555 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 119:e14dd2bf0ea3 556 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 557 #endif
nixnax 118:54d1936e3768 558 printWhileCheckingInput( pbuf );
nixnax 114:8a5d70bbc1b2 559 #ifndef TCP_HEADER_DUMP_YES
nixnax 119:e14dd2bf0ea3 560 printWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 114:8a5d70bbc1b2 561 #endif
nixnax 114:8a5d70bbc1b2 562 #endif
nixnax 29:30de79d658f6 563 }
nixnax 26:11f4eb2663a7 564
nixnax 114:8a5d70bbc1b2 565 void dumpHeaderTCP(int outGoing)
nixnax 29:30de79d658f6 566 {
nixnax 114:8a5d70bbc1b2 567 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 114:8a5d70bbc1b2 568 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 114:8a5d70bbc1b2 569 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 114:8a5d70bbc1b2 570 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 114:8a5d70bbc1b2 571 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 114:8a5d70bbc1b2 572 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 114:8a5d70bbc1b2 573 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 114:8a5d70bbc1b2 574 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 114:8a5d70bbc1b2 575 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 114:8a5d70bbc1b2 576 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 577
nixnax 119:e14dd2bf0ea3 578 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 119:e14dd2bf0ea3 579 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 119:e14dd2bf0ea3 580 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 114:8a5d70bbc1b2 581 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 114:8a5d70bbc1b2 582 flagInfo[8]=0; // null terminate string
nixnax 114:8a5d70bbc1b2 583 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 114:8a5d70bbc1b2 584 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 114:8a5d70bbc1b2 585 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 114:8a5d70bbc1b2 586 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 114:8a5d70bbc1b2 587 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 114:8a5d70bbc1b2 588 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 114:8a5d70bbc1b2 589 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 114:8a5d70bbc1b2 590 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 118:54d1936e3768 591 #else
nixnax 119:e14dd2bf0ea3 592 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 119:e14dd2bf0ea3 593 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 119:e14dd2bf0ea3 594 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 119:e14dd2bf0ea3 595 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 119:e14dd2bf0ea3 596 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 119:e14dd2bf0ea3 597 flagInfo[1]=' ';
nixnax 119:e14dd2bf0ea3 598 flagInfo[2]=0;
nixnax 118:54d1936e3768 599 #endif
nixnax 119:e14dd2bf0ea3 600 printWhileCheckingInput( flagInfo );
nixnax 119:e14dd2bf0ea3 601 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 602 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 603 putcWhileCheckingInput('\n'); // write a newline after every packet
nixnax 119:e14dd2bf0ea3 604 #endif
nixnax 119:e14dd2bf0ea3 605 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 119:e14dd2bf0ea3 606 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 118:54d1936e3768 607 }
nixnax 119:e14dd2bf0ea3 608 if( pc.readable()) printWhileCheckingInput( "Char2\n");
nixnax 114:8a5d70bbc1b2 609 #endif
nixnax 29:30de79d658f6 610 }
nixnax 29:30de79d658f6 611
nixnax 68:0b74763ae67f 612 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 613 {
nixnax 67:a63e3486bcda 614 int n=0; // number of bytes we have printed so far
nixnax 77:abf92baebb42 615 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 616 int contentLengthStart; // index where HTML starts
nixnax 93:9675adc36882 617 int xFetch, httpGetRoot; // temporary storage of strncmp results
nixnax 85:53e57ff1cf05 618
nixnax 98:3babad0d1bd4 619 ppp.httpPageCount++; // increment the number of frames we have made
nixnax 85:53e57ff1cf05 620
nixnax 98:3babad0d1bd4 621 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found GET, respond to both HTTP/1.<anything>
nixnax 99:3f56162e703e 622 xFetch = strncmp(dataStart, "GET /x", 6); // found GET /x , respond to both HTTP/1.<anything>
nixnax 119:e14dd2bf0ea3 623 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 93:9675adc36882 624 if( (httpGetRoot==0) || (xFetch==0) ) {
nixnax 115:b8ddff0e782f 625 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky\r\n"); // 200 OK header
nixnax 83:cdcb81d1910f 626 } else {
nixnax 89:2c8dd0c2a426 627 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 83:cdcb81d1910f 628 }
nixnax 83:cdcb81d1910f 629 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 630 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 631 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 632 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 633 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 634 nHeader=n; // size of HTTP header
nixnax 93:9675adc36882 635 if( httpGetRoot == 0 ) {
nixnax 83:cdcb81d1910f 636 // this is where we insert our web page into the buffer
nixnax 93:9675adc36882 637 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 93:9675adc36882 638 n = n + sizeof(rootWebPage);
nixnax 85:53e57ff1cf05 639 } else {
nixnax 109:644a59ebb5b1 640 if (xFetch == 0) { // the page request started with "GET /x"
nixnax 89:2c8dd0c2a426 641
nixnax 89:2c8dd0c2a426 642 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 89:2c8dd0c2a426 643 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 89:2c8dd0c2a426 644 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 106:d14e6b597ca3 645 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed-ppp-blinky</title>"); // html title (W3C.org required elements)
nixnax 98:3babad0d1bd4 646 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.httpPageCount); // body = the http frame count
nixnax 89:2c8dd0c2a426 647 #else
nixnax 109:644a59ebb5b1 648 #define BENCHMARK_USING_BROWSER_NO /* set to _YES if you want to use your browser as a benchmark tool */
nixnax 98:3babad0d1bd4 649 #ifndef BENCHMARK_USING_BROWSER_NO
nixnax 119:e14dd2bf0ea3 650 // 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 651 n=n+sprintf(n+dataStart, "<script>setTimeout(function(){location.reload();},10);</script><body>%d</body>",ppp.httpPageCount);
nixnax 98:3babad0d1bd4 652 #else
nixnax 98:3babad0d1bd4 653 n=n+sprintf(n+dataStart,"%d",ppp.httpPageCount); // not valid html but fast, most browsers and curl are ok with it
nixnax 98:3babad0d1bd4 654 #endif
nixnax 89:2c8dd0c2a426 655 #endif
nixnax 89:2c8dd0c2a426 656
nixnax 89:2c8dd0c2a426 657 } else {
nixnax 89:2c8dd0c2a426 658 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 89:2c8dd0c2a426 659 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>ppp-blinky-mbed</title>"); // html title (required element)
nixnax 89:2c8dd0c2a426 660 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 89:2c8dd0c2a426 661 }
nixnax 83:cdcb81d1910f 662 }
nixnax 87:9f5ac1fabd95 663 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 664 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 665
nixnax 83:cdcb81d1910f 666 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 667 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 668 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 669 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 670
nixnax 77:abf92baebb42 671 if (v2) {
nixnax 119:e14dd2bf0ea3 672 debugPrintf("HTTP Response: HTTP-header %d HTTP-content %d HTTP-total %d\n",nHeader,n-nHeader,n);
nixnax 77:abf92baebb42 673 }
nixnax 67:a63e3486bcda 674 return n; // total byte size of our response
nixnax 67:a63e3486bcda 675 }
nixnax 67:a63e3486bcda 676
nixnax 98:3babad0d1bd4 677 // if not an http response we just report the number of bytes received
nixnax 98:3babad0d1bd4 678 // this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 98:3babad0d1bd4 679 int tcpResponse(char * dataStart, int len)
nixnax 98:3babad0d1bd4 680 {
nixnax 98:3babad0d1bd4 681 int n=0; // number of bytes we have printed so far
nixnax 98:3babad0d1bd4 682 n=n+sprintf(n+dataStart,"Got %04d bytes.\n",len); // report the number of bytes received
nixnax 98:3babad0d1bd4 683 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 684 if (v2) {
nixnax 119:e14dd2bf0ea3 685 debugPrintf("TCP response %d bytes\n",n);
nixnax 98:3babad0d1bd4 686 }
nixnax 98:3babad0d1bd4 687 return n; // total byte size of our response
nixnax 98:3babad0d1bd4 688 }
nixnax 98:3babad0d1bd4 689
nixnax 29:30de79d658f6 690 void tcpHandler()
nixnax 29:30de79d658f6 691 {
nixnax 87:9f5ac1fabd95 692 // IP header
nixnax 119:e14dd2bf0ea3 693
nixnax 26:11f4eb2663a7 694 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 695 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 696 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 697 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 698 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 699 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 700 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 701 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 702 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 703 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 704
nixnax 87:9f5ac1fabd95 705 // TCP header
nixnax 87:9f5ac1fabd95 706
nixnax 87:9f5ac1fabd95 707 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 87:9f5ac1fabd95 708 char * srctcp = tcp + 0; // 2 bytes
nixnax 87:9f5ac1fabd95 709 char * dsttcp = tcp + 2; // 2 bytes
nixnax 87:9f5ac1fabd95 710 char * seqtcp = tcp + 4; // 4 bytes
nixnax 87:9f5ac1fabd95 711 char * acktcp = tcp + 8; // 4 bytes
nixnax 87:9f5ac1fabd95 712 char * offset = tcp + 12; // 4 bits
nixnax 87:9f5ac1fabd95 713 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 87:9f5ac1fabd95 714 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 87:9f5ac1fabd95 715 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 26:11f4eb2663a7 716
nixnax 26:11f4eb2663a7 717 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 718 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 719 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 720
nixnax 87:9f5ac1fabd95 721 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 722 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 87:9f5ac1fabd95 723 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 81:9ede60e9a2c8 724
nixnax 85:53e57ff1cf05 725 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 85:53e57ff1cf05 726 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 85:53e57ff1cf05 727
nixnax 85:53e57ff1cf05 728 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 87:9f5ac1fabd95 729 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 81:9ede60e9a2c8 730
nixnax 29:30de79d658f6 731 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 732 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 733 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 734 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 735 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 736
nixnax 87:9f5ac1fabd95 737 // first we shorten the TCP response header to only 20 bytes.
nixnax 87:9f5ac1fabd95 738 // this means we ignore all TCP option requests
nixnax 87:9f5ac1fabd95 739
nixnax 87:9f5ac1fabd95 740 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 87:9f5ac1fabd95 741 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 87:9f5ac1fabd95 742 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 87:9f5ac1fabd95 743 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 744 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 745 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 746
nixnax 35:e7068df4d971 747 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 748 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 87:9f5ac1fabd95 749 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 92:cb962b365cce 750
nixnax 119:e14dd2bf0ea3 751 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 119:e14dd2bf0ea3 752 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 38:ab582987926e 753
nixnax 106:d14e6b597ca3 754 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 77:abf92baebb42 755
nixnax 69:23f560087c16 756 switch ( flagsTCP ) {
nixnax 69:23f560087c16 757 case TCP_FLAG_SYN:
nixnax 87:9f5ac1fabd95 758 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 119:e14dd2bf0ea3 759 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 85:53e57ff1cf05 760 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 761 break;
nixnax 77:abf92baebb42 762 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 98:3babad0d1bd4 763 if ( strncmp(tcpDataIn, "GET /", 5) == 0) { // check for an http GET command
nixnax 118:54d1936e3768 764 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 765 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 98:3babad0d1bd4 766 } else {
nixnax 106:d14e6b597ca3 767 dataLen = tcpResponse(tcpDataOut,tcpDataSize); // not a web request, send a packet reporting number of received bytes
nixnax 69:23f560087c16 768 }
nixnax 69:23f560087c16 769 break;
nixnax 116:1272e9f7ad70 770 case TCP_FLAG_FIN:
nixnax 116:1272e9f7ad70 771 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 98:3babad0d1bd4 772 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 117:c819ae068336 773 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 85:53e57ff1cf05 774 ack_out++; // for FIN flag we always have to increase sequence by 1
nixnax 69:23f560087c16 775 break;
nixnax 77:abf92baebb42 776 default:
nixnax 69:23f560087c16 777 return; // ignore remaining packets
nixnax 93:9675adc36882 778 } // switch
nixnax 77:abf92baebb42 779
nixnax 69:23f560087c16 780 // The TCP flag handling is now done
nixnax 105:45001195b325 781 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 95:40af49390daf 782
nixnax 65:23b17c43aa0f 783 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 784 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 785 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 786 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 787
nixnax 60:2b770949c911 788 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 789 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 790 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 95:40af49390daf 791
nixnax 85:53e57ff1cf05 792 acktcp[0]=ack_out>>24;
nixnax 85:53e57ff1cf05 793 acktcp[1]=ack_out>>16;
nixnax 85:53e57ff1cf05 794 acktcp[2]=ack_out>>8;
nixnax 85:53e57ff1cf05 795 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 38:ab582987926e 796
nixnax 85:53e57ff1cf05 797 seqtcp[0]=seq_out>>24;
nixnax 85:53e57ff1cf05 798 seqtcp[1]=seq_out>>16;
nixnax 85:53e57ff1cf05 799 seqtcp[2]=seq_out>>8;
nixnax 85:53e57ff1cf05 800 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 801
nixnax 93:9675adc36882 802 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 93:9675adc36882 803
nixnax 114:8a5d70bbc1b2 804 // increment our outgoing ip packet counter
nixnax 114:8a5d70bbc1b2 805 ppp.ip.ident++; // get next ident number for our packet
nixnax 114:8a5d70bbc1b2 806 ident[0] = ppp.ip.ident>>8;
nixnax 114:8a5d70bbc1b2 807 ident[1] = ppp.ip.ident>>0; // insert OUR ident
nixnax 93:9675adc36882 808
nixnax 106:d14e6b597ca3 809 // Now we recalculate all the header sizes
nixnax 38:ab582987926e 810 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 811 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 812 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 813 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 814 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 815
nixnax 38:ab582987926e 816 // the header is all set up, now do the IP and TCP checksums
nixnax 61:b3c1a04efd0a 817 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 818 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 819 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 820
nixnax 64:677b9713a120 821 // 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 822 // 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 823
nixnax 87:9f5ac1fabd95 824 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 825 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 826 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 827 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 828 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 829 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 830 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 831
nixnax 61:b3c1a04efd0a 832 // pseudo-header built, now we can calculate TCP checksum
nixnax 29:30de79d658f6 833 checksumtcp[0]=0;
nixnax 29:30de79d658f6 834 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 835 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 836 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 837 checksumtcp[1]=pseudoHeaderSum;
nixnax 87:9f5ac1fabd95 838 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 114:8a5d70bbc1b2 839 dumpHeaderIP(1); // dump outgoing IP header
nixnax 114:8a5d70bbc1b2 840 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 119:e14dd2bf0ea3 841 for (int i=0; i<35000/50; i++) { // a 35 ms delay before sending frame
nixnax 119:e14dd2bf0ea3 842 fillbuf(); // catch any incoming characters
nixnax 119:e14dd2bf0ea3 843 wait_us(50); // wait less than 1 character duration at 115200
nixnax 119:e14dd2bf0ea3 844 }
nixnax 93:9675adc36882 845 send_pppFrame(); // All preparation complete - send the TCP response
nixnax 29:30de79d658f6 846 }
nixnax 26:11f4eb2663a7 847
nixnax 29:30de79d658f6 848 void dumpDataTCP()
nixnax 29:30de79d658f6 849 {
nixnax 26:11f4eb2663a7 850 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 851 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 852 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 853 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 854 if (v1) {
nixnax 119:e14dd2bf0ea3 855 debugPrintf("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 856 }
nixnax 29:30de79d658f6 857 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 858 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 119:e14dd2bf0ea3 859 debugPrintf("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 860 }
nixnax 29:30de79d658f6 861 }
nixnax 26:11f4eb2663a7 862
nixnax 29:30de79d658f6 863 void TCPpacket()
nixnax 29:30de79d658f6 864 {
nixnax 114:8a5d70bbc1b2 865 dumpHeaderIP(0); // dump incoming packet header
nixnax 114:8a5d70bbc1b2 866 dumpHeaderTCP(0); // dump incoming packet header
nixnax 77:abf92baebb42 867 if (v2) {
nixnax 77:abf92baebb42 868 dumpDataTCP();
nixnax 77:abf92baebb42 869 }
nixnax 26:11f4eb2663a7 870 tcpHandler();
nixnax 11:f58998c24f0b 871 }
nixnax 11:f58998c24f0b 872
nixnax 29:30de79d658f6 873 void otherProtocol()
nixnax 29:30de79d658f6 874 {
nixnax 119:e14dd2bf0ea3 875 debugPrintf("Other IP protocol");
nixnax 29:30de79d658f6 876 }
nixnax 26:11f4eb2663a7 877
nixnax 29:30de79d658f6 878 void IPframe()
nixnax 29:30de79d658f6 879 {
nixnax 10:74f8233f72c0 880 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 881 switch (protocol) {
nixnax 29:30de79d658f6 882 case 1:
nixnax 29:30de79d658f6 883 ICMPpacket();
nixnax 29:30de79d658f6 884 break;
nixnax 29:30de79d658f6 885 case 2:
nixnax 29:30de79d658f6 886 IGMPpacket();
nixnax 29:30de79d658f6 887 break;
nixnax 29:30de79d658f6 888 case 17:
nixnax 29:30de79d658f6 889 UDPpacket();
nixnax 29:30de79d658f6 890 break;
nixnax 29:30de79d658f6 891 case 6:
nixnax 29:30de79d658f6 892 TCPpacket();
nixnax 29:30de79d658f6 893 break;
nixnax 29:30de79d658f6 894 default:
nixnax 29:30de79d658f6 895 otherProtocol();
nixnax 29:30de79d658f6 896 }
nixnax 29:30de79d658f6 897 }
nixnax 9:0992486d4a30 898
nixnax 29:30de79d658f6 899 void LCPconfReq()
nixnax 29:30de79d658f6 900 {
nixnax 119:e14dd2bf0ea3 901 debugPrintf("LCP Config ");
nixnax 9:0992486d4a30 902 if (ppp.pkt.buf[7] != 4) {
nixnax 111:6a3b77c065c0 903 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 119:e14dd2bf0ea3 904 debugPrintf("Reject\n");
nixnax 93:9675adc36882 905 send_pppFrame();
nixnax 9:0992486d4a30 906 } else {
nixnax 9:0992486d4a30 907 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 119:e14dd2bf0ea3 908 debugPrintf("Ack\n");
nixnax 93:9675adc36882 909 send_pppFrame();
nixnax 119:e14dd2bf0ea3 910 debugPrintf("LCP Ask\n");
nixnax 11:f58998c24f0b 911 ppp.pkt.buf[4]=1; // request no options
nixnax 93:9675adc36882 912 send_pppFrame();
nixnax 9:0992486d4a30 913 }
nixnax 9:0992486d4a30 914 }
nixnax 9:0992486d4a30 915
nixnax 29:30de79d658f6 916 void LCPconfAck()
nixnax 29:30de79d658f6 917 {
nixnax 119:e14dd2bf0ea3 918 debugPrintf("LCP Ack\n");
nixnax 29:30de79d658f6 919 }
nixnax 9:0992486d4a30 920
nixnax 29:30de79d658f6 921 void LCPend()
nixnax 29:30de79d658f6 922 {
nixnax 29:30de79d658f6 923 ppp.pkt.buf[4]=6;
nixnax 93:9675adc36882 924 send_pppFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 925 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 926 pppInitStruct(); // flush the receive buffer
nixnax 119:e14dd2bf0ea3 927 debugPrintf("LCP End\n");
nixnax 9:0992486d4a30 928 }
nixnax 9:0992486d4a30 929
nixnax 29:30de79d658f6 930 void LCPother()
nixnax 29:30de79d658f6 931 {
nixnax 119:e14dd2bf0ea3 932 debugPrintf("LCP Other\n");
nixnax 95:40af49390daf 933 dumpPPPFrame();
nixnax 29:30de79d658f6 934 }
nixnax 29:30de79d658f6 935
nixnax 29:30de79d658f6 936 void LCPframe()
nixnax 29:30de79d658f6 937 {
nixnax 29:30de79d658f6 938 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 939 switch (code) {
nixnax 29:30de79d658f6 940 case 1:
nixnax 29:30de79d658f6 941 LCPconfReq();
nixnax 29:30de79d658f6 942 break; // config request
nixnax 29:30de79d658f6 943 case 2:
nixnax 29:30de79d658f6 944 LCPconfAck();
nixnax 29:30de79d658f6 945 break; // config ack
nixnax 29:30de79d658f6 946 case 5:
nixnax 29:30de79d658f6 947 LCPend();
nixnax 29:30de79d658f6 948 break; // end connection
nixnax 29:30de79d658f6 949 default:
nixnax 29:30de79d658f6 950 LCPother();
nixnax 29:30de79d658f6 951 }
nixnax 9:0992486d4a30 952 }
nixnax 9:0992486d4a30 953
nixnax 29:30de79d658f6 954 void discardedFrame()
nixnax 29:30de79d658f6 955 {
nixnax 29:30de79d658f6 956 if (v0) {
nixnax 119:e14dd2bf0ea3 957 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 958 }
nixnax 9:0992486d4a30 959 }
nixnax 9:0992486d4a30 960
nixnax 29:30de79d658f6 961 void determinePacketType()
nixnax 29:30de79d658f6 962 {
nixnax 29:30de79d658f6 963 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 119:e14dd2bf0ea3 964 debugPrintf("byte0 != ff\n");
nixnax 29:30de79d658f6 965 return;
nixnax 29:30de79d658f6 966 }
nixnax 29:30de79d658f6 967 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 119:e14dd2bf0ea3 968 debugPrintf("byte1 != 3\n");
nixnax 29:30de79d658f6 969 return;
nixnax 29:30de79d658f6 970 }
nixnax 29:30de79d658f6 971 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 119:e14dd2bf0ea3 972 debugPrintf("byte2 != 21\n");
nixnax 29:30de79d658f6 973 return;
nixnax 29:30de79d658f6 974 }
nixnax 9:0992486d4a30 975 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 976 switch (packetType) {
nixnax 29:30de79d658f6 977 case 0xc0:
nixnax 29:30de79d658f6 978 LCPframe();
nixnax 29:30de79d658f6 979 break; // link control
nixnax 29:30de79d658f6 980 case 0x80:
nixnax 29:30de79d658f6 981 IPCPframe();
nixnax 29:30de79d658f6 982 break; // IP control
nixnax 29:30de79d658f6 983 case 0x00:
nixnax 29:30de79d658f6 984 IPframe();
nixnax 29:30de79d658f6 985 break; // IP itself
nixnax 29:30de79d658f6 986 default:
nixnax 29:30de79d658f6 987 discardedFrame();
nixnax 9:0992486d4a30 988 }
nixnax 29:30de79d658f6 989 }
nixnax 9:0992486d4a30 990
nixnax 119:e14dd2bf0ea3 991 void wait_for_PPP_frame()
nixnax 50:ad4e7c3c88e5 992 {
nixnax 85:53e57ff1cf05 993 while(1) {
nixnax 93:9675adc36882 994 fillbuf(); // handle received characters
nixnax 81:9ede60e9a2c8 995 if ( rxbufNotEmpty() ) {
nixnax 81:9ede60e9a2c8 996 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 997 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 998 if (rx==FRAME_7E) {
nixnax 119:e14dd2bf0ea3 999 if (ppp.firstFrame) { // is this the first frame start
nixnax 119:e14dd2bf0ea3 1000 ppp.firstFrame=0;
nixnax 119:e14dd2bf0ea3 1001 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember first frame start
nixnax 119:e14dd2bf0ea3 1002 break;
nixnax 119:e14dd2bf0ea3 1003 } else {
nixnax 119:e14dd2bf0ea3 1004 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 119:e14dd2bf0ea3 1005 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 119:e14dd2bf0ea3 1006 ppp.rx.rtail = ppp.rx.tail;
nixnax 119:e14dd2bf0ea3 1007 ppp.hdlc.frameStartIndex = ppp.rx.tail; // where next frame will start
nixnax 119:e14dd2bf0ea3 1008 break;
nixnax 119:e14dd2bf0ea3 1009 }
nixnax 50:ad4e7c3c88e5 1010 }
nixnax 50:ad4e7c3c88e5 1011 }
nixnax 85:53e57ff1cf05 1012 }
nixnax 50:ad4e7c3c88e5 1013 }
nixnax 50:ad4e7c3c88e5 1014
nixnax 29:30de79d658f6 1015 void scanForConnectString()
nixnax 29:30de79d658f6 1016 {
nixnax 81:9ede60e9a2c8 1017 while(ppp.online == 0) {
nixnax 114:8a5d70bbc1b2 1018 fillbuf(); // gather received characters
nixnax 81:9ede60e9a2c8 1019 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 106:d14e6b597ca3 1020 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 107:5fe806713d49 1021 if (found1 != NULL) {
nixnax 107:5fe806713d49 1022 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 119:e14dd2bf0ea3 1023 if (v0) debugPrintf("Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 107:5fe806713d49 1024 pc.puts("CLIENTSERVER");
nixnax 107:5fe806713d49 1025 ppp.online=1; // we are connected, so we can stop looking for the connect string
nixnax 119:e14dd2bf0ea3 1026 fillbuf();
nixnax 9:0992486d4a30 1027 }
nixnax 9:0992486d4a30 1028 }
nixnax 103:4f5512dd11cf 1029 }
nixnax 81:9ede60e9a2c8 1030
nixnax 0:2cf4880c312a 1031 int main()
nixnax 0:2cf4880c312a 1032 {
nixnax 14:c65831c25aaa 1033 pc.baud(115200); // USB virtual serial port
nixnax 118:54d1936e3768 1034 debugBaudRate(115200); // baud rate for our debug port if we have one
nixnax 119:e14dd2bf0ea3 1035 debugPrintf("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home on our debug port - Tera Term is a good VT100 terminal
nixnax 9:0992486d4a30 1036 pppInitStruct(); // initialize all the PPP properties
nixnax 0:2cf4880c312a 1037 while(1) {
nixnax 119:e14dd2bf0ea3 1038 scanForConnectString(); // wait for connect command from windows dial up networking
nixnax 81:9ede60e9a2c8 1039 while(ppp.online) {
nixnax 119:e14dd2bf0ea3 1040 wait_for_PPP_frame();
nixnax 81:9ede60e9a2c8 1041 }
nixnax 7:ab147f5e97ac 1042 }
nixnax 105:45001195b325 1043 }