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@126:4e1058fa2128, 2017-08-09 (annotated)

Committer:
nixnax
Date:
Wed Aug 09 13:11:55 2017 +0000
Revision:
126:4e1058fa2128
Parent:
125:ea88200b1df6
Child:
127:3ea6f776e287
Rxbuflen back to 1<<11

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 126:4e1058fa2128 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 124:18ef53f1d8b7 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 126:4e1058fa2128 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 122:963abcbff21e 124 #define PPP_max_size 2500
nixnax 123:fc64fc6caae0 125 // we are assuming 1000 bytes more than MTU size of 1500 - due to the PPP encoding of special bytes
nixnax 122:963abcbff21e 126 char buf[PPP_max_size]; // send and receive buffer large enough for raw, encoded PPP/HDLC frames
nixnax 38:ab582987926e 127 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 128 struct {
nixnax 50:ad4e7c3c88e5 129 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 130 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 131 } hdlc; // hdlc frame objects
nixnax 114:8a5d70bbc1b2 132 struct {
nixnax 114:8a5d70bbc1b2 133 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 114:8a5d70bbc1b2 134 } ip; // ip related object
nixnax 29:30de79d658f6 135 };
nixnax 31:e000c1b9c565 136
nixnax 29:30de79d658f6 137 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 138
nixnax 93:9675adc36882 139 // Initialize our global structure, clear the buffer, etc.
nixnax 29:30de79d658f6 140 void pppInitStruct()
nixnax 29:30de79d658f6 141 {
nixnax 81:9ede60e9a2c8 142 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 29:30de79d658f6 143 ppp.online=0;
nixnax 29:30de79d658f6 144 ppp.rx.tail=0;
nixnax 93:9675adc36882 145 ppp.rx.rtail=0;
nixnax 29:30de79d658f6 146 ppp.rx.head=0;
nixnax 81:9ede60e9a2c8 147 ppp.rx.buflevel=0;
nixnax 29:30de79d658f6 148 ppp.pkt.len=0;
nixnax 114:8a5d70bbc1b2 149 ppp.ip.ident=10000; // easy to recognize in ip packet dumps
nixnax 29:30de79d658f6 150 ppp.ledState=0;
nixnax 81:9ede60e9a2c8 151 ppp.hdlc.frameStartIndex=0;
nixnax 98:3babad0d1bd4 152 ppp.httpPageCount=0;
nixnax 119:e14dd2bf0ea3 153 ppp.firstFrame=1;
nixnax 29:30de79d658f6 154 }
nixnax 26:11f4eb2663a7 155
nixnax 43:aa57db08995d 156 void led1Toggle()
nixnax 43:aa57db08995d 157 {
nixnax 43:aa57db08995d 158 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 93:9675adc36882 159 led1 = ppp.ledState; // toggle led
nixnax 43:aa57db08995d 160 }
nixnax 43:aa57db08995d 161
nixnax 85:53e57ff1cf05 162 // fill our own receive buffer with characters from the PPP serial port
nixnax 85:53e57ff1cf05 163 void fillbuf()
nixnax 0:2cf4880c312a 164 {
nixnax 107:5fe806713d49 165 char ch;
nixnax 85:53e57ff1cf05 166 if ( pc.readable() ) {
nixnax 85:53e57ff1cf05 167 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 93:9675adc36882 168 if ( hd == ppp.rx.rtail ) {
nixnax 119:e14dd2bf0ea3 169 debugPrintf("\nReceive buffer full\n");
nixnax 85:53e57ff1cf05 170 return;
nixnax 83:cdcb81d1910f 171 }
nixnax 107:5fe806713d49 172 ch = pc.getc(); // read new character
nixnax 107:5fe806713d49 173 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 107:5fe806713d49 174 if ( ppp.online == 0 ) {
nixnax 107:5fe806713d49 175 if (ch == 0x7E) {
nixnax 107:5fe806713d49 176 ppp.online = 1;
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 125:ea88200b1df6 194 void putsWhileCheckingInput( 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 124:18ef53f1d8b7 201 }
nixnax 118:54d1936e3768 202 #endif
nixnax 118:54d1936e3768 203 }
nixnax 118:54d1936e3768 204
nixnax 124:18ef53f1d8b7 205 // a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 124:18ef53f1d8b7 206 void qq()
nixnax 124:18ef53f1d8b7 207 {
nixnax 125:ea88200b1df6 208 if ( pc.readable() ) putsWhileCheckingInput( "Character available!\n" );
nixnax 124:18ef53f1d8b7 209 }
nixnax 124:18ef53f1d8b7 210
nixnax 118:54d1936e3768 211 void crcReset()
nixnax 118:54d1936e3768 212 {
nixnax 118:54d1936e3768 213 ppp.crc=0xffff; // crc restart
nixnax 118:54d1936e3768 214 }
nixnax 118:54d1936e3768 215
nixnax 118:54d1936e3768 216 void crcDo(int x) // cumulative crc
nixnax 118:54d1936e3768 217 {
nixnax 118:54d1936e3768 218 for (int i=0; i<8; i++) {
nixnax 118:54d1936e3768 219 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 118:54d1936e3768 220 x>>=1;
nixnax 118:54d1936e3768 221 }
nixnax 124:18ef53f1d8b7 222 fillbuf(); // handle input
nixnax 118:54d1936e3768 223 }
nixnax 118:54d1936e3768 224
nixnax 118:54d1936e3768 225 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 118:54d1936e3768 226 {
nixnax 118:54d1936e3768 227 crcReset();
nixnax 118:54d1936e3768 228 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 118:54d1936e3768 229 return ppp.crc;
nixnax 118:54d1936e3768 230 }
nixnax 118:54d1936e3768 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 120:bef89e4c906e 245 char pbuf[30];
nixnax 120:bef89e4c906e 246 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 124:18ef53f1d8b7 247 fillbuf();
nixnax 124:18ef53f1d8b7 248 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 124:18ef53f1d8b7 249 fillbuf();
nixnax 125:ea88200b1df6 250 putsWhileCheckingInput(pbuf);
nixnax 124:18ef53f1d8b7 251 }
nixnax 124:18ef53f1d8b7 252 fillbuf();
nixnax 124:18ef53f1d8b7 253 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 124:18ef53f1d8b7 254 fillbuf();
nixnax 125:ea88200b1df6 255 putsWhileCheckingInput(pbuf);
nixnax 95:40af49390daf 256 }
nixnax 95:40af49390daf 257
nixnax 119:e14dd2bf0ea3 258 void processPPPFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 259 {
nixnax 38:ab582987926e 260 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 261 if(start==end) {
nixnax 111:6a3b77c065c0 262 return; // empty frame
nixnax 29:30de79d658f6 263 }
nixnax 9:0992486d4a30 264 crcReset();
nixnax 9:0992486d4a30 265 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 266 ppp.pkt.len=0;
nixnax 9:0992486d4a30 267 int unstuff=0;
nixnax 17:4918c893d802 268 int idx = start;
nixnax 17:4918c893d802 269 while(1) {
nixnax 124:18ef53f1d8b7 270 fillbuf();
nixnax 9:0992486d4a30 271 if (unstuff==0) {
nixnax 72:ad3d12753acf 272 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 273 else {
nixnax 72:ad3d12753acf 274 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 275 ppp.pkt.len++;
nixnax 29:30de79d658f6 276 dest++;
nixnax 72:ad3d12753acf 277 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 278 }
nixnax 66:f005b9fdf4d1 279 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 280 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 281 ppp.pkt.len++;
nixnax 29:30de79d658f6 282 dest++;
nixnax 72:ad3d12753acf 283 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 284 unstuff=0;
nixnax 9:0992486d4a30 285 }
nixnax 81:9ede60e9a2c8 286 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 287 if (idx == end) break;
nixnax 9:0992486d4a30 288 }
nixnax 29:30de79d658f6 289 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 120:bef89e4c906e 290 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 9:0992486d4a30 291 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 292 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 293 determinePacketType();
nixnax 90:55e0f243a7ce 294 } else {
nixnax 124:18ef53f1d8b7 295 #ifdef REPORT_FCS_ERROR_YES
nixnax 118:54d1936e3768 296 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 297 fillbuf();
nixnax 124:18ef53f1d8b7 298 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 120:bef89e4c906e 299 fillbuf();
nixnax 125:ea88200b1df6 300 putsWhileCheckingInput( pbuf );
nixnax 120:bef89e4c906e 301 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 124:18ef53f1d8b7 302 #endif
nixnax 9:0992486d4a30 303 }
nixnax 9:0992486d4a30 304 }
nixnax 9:0992486d4a30 305
nixnax 124:18ef53f1d8b7 306 void pcPutcWhileCheckingInput(int ch)
nixnax 124:18ef53f1d8b7 307 {
nixnax 124:18ef53f1d8b7 308 fillbuf(); // check input
nixnax 124:18ef53f1d8b7 309 pc.putc(ch);
nixnax 124:18ef53f1d8b7 310 fillbuf();
nixnax 124:18ef53f1d8b7 311 }
nixnax 124:18ef53f1d8b7 312
nixnax 29:30de79d658f6 313 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 314 {
nixnax 29:30de79d658f6 315 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 124:18ef53f1d8b7 316 pcPutcWhileCheckingInput(0x7d);
nixnax 124:18ef53f1d8b7 317 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 318 } else {
nixnax 124:18ef53f1d8b7 319 pcPutcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 320 }
nixnax 11:f58998c24f0b 321 }
nixnax 9:0992486d4a30 322
nixnax 93:9675adc36882 323 void send_pppFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 324 {
nixnax 17:4918c893d802 325 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 326 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 327 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 124:18ef53f1d8b7 328 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 95:40af49390daf 329 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 93:9675adc36882 330 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 93:9675adc36882 331 }
nixnax 124:18ef53f1d8b7 332 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 333 }
nixnax 9:0992486d4a30 334
nixnax 93:9675adc36882 335 void ipcpConfigRequestHandler()
nixnax 29:30de79d658f6 336 {
nixnax 119:e14dd2bf0ea3 337 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 92:cb962b365cce 338 ppp.pkt.buf[4]=2; // change code to ack
nixnax 108:f77ec4605945 339 send_pppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 106:d14e6b597ca3 340
nixnax 119:e14dd2bf0ea3 341 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 92:cb962b365cce 342 ppp.pkt.buf[4]=1; // change code to request
nixnax 106:d14e6b597ca3 343 ppp.pkt.buf[7]=4; // no options in this request
nixnax 106:d14e6b597ca3 344 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 124:18ef53f1d8b7 345 send_pppFrame(); // send our request
nixnax 9:0992486d4a30 346 }
nixnax 9:0992486d4a30 347
nixnax 93:9675adc36882 348 void ipcpAckHandler()
nixnax 29:30de79d658f6 349 {
nixnax 119:e14dd2bf0ea3 350 debugPrintf("Their IPCP Grant\n");
nixnax 29:30de79d658f6 351 }
nixnax 9:0992486d4a30 352
nixnax 93:9675adc36882 353 void ipcpNackHandler()
nixnax 29:30de79d658f6 354 {
nixnax 119:e14dd2bf0ea3 355 debugPrintf("Their IPCP Nack, Our ACK\n");
nixnax 107:5fe806713d49 356 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 106:d14e6b597ca3 357 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 106:d14e6b597ca3 358 send_pppFrame(); // let's request this IP address as ours
nixnax 106:d14e6b597ca3 359 } // if it's not an IP nack we ignore it
nixnax 29:30de79d658f6 360 }
nixnax 9:0992486d4a30 361
nixnax 93:9675adc36882 362 void ipcpDefaultHandler()
nixnax 29:30de79d658f6 363 {
nixnax 119:e14dd2bf0ea3 364 debugPrintf("Their IPCP Other\n");
nixnax 29:30de79d658f6 365 }
nixnax 29:30de79d658f6 366
nixnax 29:30de79d658f6 367 void IPCPframe()
nixnax 29:30de79d658f6 368 {
nixnax 9:0992486d4a30 369 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 370 switch (code) {
nixnax 29:30de79d658f6 371 case 1:
nixnax 93:9675adc36882 372 ipcpConfigRequestHandler();
nixnax 29:30de79d658f6 373 break;
nixnax 29:30de79d658f6 374 case 2:
nixnax 93:9675adc36882 375 ipcpAckHandler();
nixnax 29:30de79d658f6 376 break;
nixnax 29:30de79d658f6 377 case 3:
nixnax 93:9675adc36882 378 ipcpNackHandler();
nixnax 29:30de79d658f6 379 break;
nixnax 29:30de79d658f6 380 default:
nixnax 93:9675adc36882 381 ipcpDefaultHandler();
nixnax 9:0992486d4a30 382 }
nixnax 29:30de79d658f6 383 }
nixnax 9:0992486d4a30 384
nixnax 29:30de79d658f6 385 void UDPpacket()
nixnax 29:30de79d658f6 386 {
nixnax 12:db0dc91f0231 387 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 388 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 389 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 118:54d1936e3768 390 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 391 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 392 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 393 #endif
nixnax 12:db0dc91f0231 394 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 395 char * udpInf = udpBlock+8; // actual start of info
nixnax 118:54d1936e3768 396 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 397 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 398 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 399 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 400 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 401 #endif
nixnax 29:30de79d658f6 402 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 403 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 119:e14dd2bf0ea3 404 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 119:e14dd2bf0ea3 405 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 119:e14dd2bf0ea3 406 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 29:30de79d658f6 407 int printSize = udpLength;
nixnax 29:30de79d658f6 408 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 409 if (v1) {
nixnax 29:30de79d658f6 410 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 411 char ch = udpInf[i];
nixnax 29:30de79d658f6 412 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 413 debugPrintf("%c", ch);
nixnax 29:30de79d658f6 414 } else {
nixnax 119:e14dd2bf0ea3 415 debugPrintf("_");
nixnax 29:30de79d658f6 416 }
nixnax 29:30de79d658f6 417 }
nixnax 29:30de79d658f6 418 }
nixnax 119:e14dd2bf0ea3 419 if (v0) debugPrintf("\n");
nixnax 12:db0dc91f0231 420 }
nixnax 11:f58998c24f0b 421
nixnax 76:00e208cceb8b 422 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 423 {
nixnax 75:0d513869231f 424 unsigned int sum=0;
nixnax 76:00e208cceb8b 425 unsigned char placeHolder;
nixnax 29:30de79d658f6 426 if (len&1) {
nixnax 76:00e208cceb8b 427 placeHolder = ptr[len]; // when length is odd stuff in a zero byte
nixnax 76:00e208cceb8b 428 ptr[len]=0;
nixnax 29:30de79d658f6 429 }
nixnax 29:30de79d658f6 430 for (int i=0; i<len/2; i++) {
nixnax 124:18ef53f1d8b7 431 fillbuf();
nixnax 76:00e208cceb8b 432 unsigned int hi = *ptr;
nixnax 29:30de79d658f6 433 ptr++;
nixnax 76:00e208cceb8b 434 unsigned int lo = *ptr;
nixnax 29:30de79d658f6 435 ptr++;
nixnax 76:00e208cceb8b 436 unsigned int val = ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 437 sum = sum + val;
nixnax 11:f58998c24f0b 438 }
nixnax 29:30de79d658f6 439 if (len&1) {
nixnax 76:00e208cceb8b 440 ptr[len] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 441 }
nixnax 76:00e208cceb8b 442 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 443 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 444 return ~sum;
nixnax 29:30de79d658f6 445 }
nixnax 11:f58998c24f0b 446
nixnax 29:30de79d658f6 447 void headerCheckSum()
nixnax 29:30de79d658f6 448 {
nixnax 11:f58998c24f0b 449 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 450 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 451 int sum=0;
nixnax 11:f58998c24f0b 452
nixnax 29:30de79d658f6 453 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 454 int hi = *ptr;
nixnax 29:30de79d658f6 455 ptr++;
nixnax 29:30de79d658f6 456 int lo = *ptr;
nixnax 29:30de79d658f6 457 ptr++;
nixnax 11:f58998c24f0b 458 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 459 sum = sum + val;
nixnax 124:18ef53f1d8b7 460 fillbuf();
nixnax 11:f58998c24f0b 461 }
nixnax 11:f58998c24f0b 462 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 463 sum = ~sum;
nixnax 11:f58998c24f0b 464 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 465 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 466 }
nixnax 9:0992486d4a30 467
nixnax 29:30de79d658f6 468 void ICMPpacket() // internet control message protocol
nixnax 124:18ef53f1d8b7 469 {
nixnax 12:db0dc91f0231 470 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 471 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 472 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 473 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 474 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 475 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 476 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 477 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 478 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 479 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 480 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 481 char * dstAdr = ipPkt+16;
nixnax 124:18ef53f1d8b7 482 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 18:3e35de1bc877 483 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 484 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 125:ea88200b1df6 485 if(1) {
nixnax 124:18ef53f1d8b7 486 char pbuf[50];
nixnax 124:18ef53f1d8b7 487 fillbuf();
nixnax 124:18ef53f1d8b7 488 sprintf(pbuf, "ICMP PING %d.%d.%d.%d %d.%d.%d.%d ", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3],dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 125:ea88200b1df6 489 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 490 fillbuf();
nixnax 125:ea88200b1df6 491 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 124:18ef53f1d8b7 492 fillbuf();
nixnax 125:ea88200b1df6 493 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 494 }
nixnax 124:18ef53f1d8b7 495 #endif
nixnax 29:30de79d658f6 496 char src[4];
nixnax 29:30de79d658f6 497 char dst[4];
nixnax 12:db0dc91f0231 498 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 499 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 500 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 501 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 502 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 503 chkSum[0]=0;
nixnax 29:30de79d658f6 504 chkSum[1]=0;
nixnax 12:db0dc91f0231 505 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 506 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 507 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 508 icmpSum[0]=0;
nixnax 29:30de79d658f6 509 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 510 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 511 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 512 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 513 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 514
nixnax 16:cb0b80c24ba2 515 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 516 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 517 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 124:18ef53f1d8b7 518 if (0) {
nixnax 29:30de79d658f6 519 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 520 char ch = icmpData[i];
nixnax 29:30de79d658f6 521 if (ch>31 && ch<127) {
nixnax 124:18ef53f1d8b7 522 putcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 523 } else {
nixnax 124:18ef53f1d8b7 524 putcWhileCheckingInput('_');
nixnax 29:30de79d658f6 525 }
nixnax 29:30de79d658f6 526 }
nixnax 124:18ef53f1d8b7 527 putcWhileCheckingInput('\n');
nixnax 29:30de79d658f6 528 }
nixnax 93:9675adc36882 529 send_pppFrame(); // reply to the ping
nixnax 12:db0dc91f0231 530 } else {
nixnax 29:30de79d658f6 531 if (v0) {
nixnax 119:e14dd2bf0ea3 532 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 533 }
nixnax 124:18ef53f1d8b7 534 }
nixnax 11:f58998c24f0b 535 }
nixnax 11:f58998c24f0b 536
nixnax 29:30de79d658f6 537 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 538 {
nixnax 119:e14dd2bf0ea3 539 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 540 }
nixnax 11:f58998c24f0b 541
nixnax 114:8a5d70bbc1b2 542 void dumpHeaderIP (int outGoing)
nixnax 29:30de79d658f6 543 {
nixnax 114:8a5d70bbc1b2 544 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 119:e14dd2bf0ea3 545 fillbuf(); // we are expecting the first character of the next packet
nixnax 114:8a5d70bbc1b2 546 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 114:8a5d70bbc1b2 547 char * ident = ipPkt+4; // 2 bytes
nixnax 118:54d1936e3768 548 #ifdef UNUSED_IP_VARIABLES
nixnax 114:8a5d70bbc1b2 549 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 114:8a5d70bbc1b2 550 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 114:8a5d70bbc1b2 551 char * version = ipPkt; // top 4 bits
nixnax 114:8a5d70bbc1b2 552 char * ihl = ipPkt; // bottom 4 bits
nixnax 114:8a5d70bbc1b2 553 char * dscp = ipPkt+1; // top 6 bits
nixnax 114:8a5d70bbc1b2 554 char * ecn = ipPkt+1; // lower 2 bits
nixnax 114:8a5d70bbc1b2 555 char * pktLen = ipPkt+2; // 2 bytes
nixnax 114:8a5d70bbc1b2 556 char * flags = ipPkt+6; // 2 bits
nixnax 114:8a5d70bbc1b2 557 char * ttl = ipPkt+8; // 1 byte
nixnax 114:8a5d70bbc1b2 558 char * protocol = ipPkt+9; // 1 byte
nixnax 114:8a5d70bbc1b2 559 char * headercheck= ipPkt+10; // 2 bytes
nixnax 114:8a5d70bbc1b2 560 int versionIP = (version[0]>>4)&0xf;
nixnax 114:8a5d70bbc1b2 561 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 114:8a5d70bbc1b2 562 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 114:8a5d70bbc1b2 563 int ecnIP = ecn[0]&3;
nixnax 114:8a5d70bbc1b2 564 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 114:8a5d70bbc1b2 565 int flagsIP = flags[0]>>14&3;
nixnax 114:8a5d70bbc1b2 566 int ttlIP = ttl[0];
nixnax 114:8a5d70bbc1b2 567 int protocolIP = protocol[0];
nixnax 114:8a5d70bbc1b2 568 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 569 #endif
nixnax 119:e14dd2bf0ea3 570 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 119:e14dd2bf0ea3 571 char pbuf[50]; // local print buffer
nixnax 118:54d1936e3768 572 int n=0;
nixnax 119:e14dd2bf0ea3 573 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 119:e14dd2bf0ea3 574 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 575 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 576 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 577 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 119:e14dd2bf0ea3 578 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 119:e14dd2bf0ea3 579 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 580 #endif
nixnax 125:ea88200b1df6 581 putsWhileCheckingInput( pbuf );
nixnax 114:8a5d70bbc1b2 582 #ifndef TCP_HEADER_DUMP_YES
nixnax 125:ea88200b1df6 583 putsWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 114:8a5d70bbc1b2 584 #endif
nixnax 114:8a5d70bbc1b2 585 #endif
nixnax 29:30de79d658f6 586 }
nixnax 26:11f4eb2663a7 587
nixnax 114:8a5d70bbc1b2 588 void dumpHeaderTCP(int outGoing)
nixnax 29:30de79d658f6 589 {
nixnax 114:8a5d70bbc1b2 590 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 114:8a5d70bbc1b2 591 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 114:8a5d70bbc1b2 592 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 114:8a5d70bbc1b2 593 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 114:8a5d70bbc1b2 594 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 114:8a5d70bbc1b2 595 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 114:8a5d70bbc1b2 596 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 114:8a5d70bbc1b2 597 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 114:8a5d70bbc1b2 598 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 114:8a5d70bbc1b2 599 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 600
nixnax 119:e14dd2bf0ea3 601 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 119:e14dd2bf0ea3 602 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 119:e14dd2bf0ea3 603 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 114:8a5d70bbc1b2 604 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 114:8a5d70bbc1b2 605 flagInfo[8]=0; // null terminate string
nixnax 114:8a5d70bbc1b2 606 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 114:8a5d70bbc1b2 607 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 114:8a5d70bbc1b2 608 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 114:8a5d70bbc1b2 609 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 114:8a5d70bbc1b2 610 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 114:8a5d70bbc1b2 611 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 114:8a5d70bbc1b2 612 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 114:8a5d70bbc1b2 613 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 118:54d1936e3768 614 #else
nixnax 119:e14dd2bf0ea3 615 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 119:e14dd2bf0ea3 616 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 119:e14dd2bf0ea3 617 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 119:e14dd2bf0ea3 618 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 119:e14dd2bf0ea3 619 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 124:18ef53f1d8b7 620 flagInfo[1]=0; // ' '
nixnax 119:e14dd2bf0ea3 621 flagInfo[2]=0;
nixnax 118:54d1936e3768 622 #endif
nixnax 125:ea88200b1df6 623 putsWhileCheckingInput( flagInfo );
nixnax 119:e14dd2bf0ea3 624 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 625 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 125:ea88200b1df6 626 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 119:e14dd2bf0ea3 627 #endif
nixnax 119:e14dd2bf0ea3 628 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 119:e14dd2bf0ea3 629 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 118:54d1936e3768 630 }
nixnax 114:8a5d70bbc1b2 631 #endif
nixnax 29:30de79d658f6 632 }
nixnax 29:30de79d658f6 633
nixnax 68:0b74763ae67f 634 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 635 {
nixnax 67:a63e3486bcda 636 int n=0; // number of bytes we have printed so far
nixnax 77:abf92baebb42 637 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 638 int contentLengthStart; // index where HTML starts
nixnax 93:9675adc36882 639 int xFetch, httpGetRoot; // temporary storage of strncmp results
nixnax 85:53e57ff1cf05 640
nixnax 98:3babad0d1bd4 641 ppp.httpPageCount++; // increment the number of frames we have made
nixnax 85:53e57ff1cf05 642
nixnax 98:3babad0d1bd4 643 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found GET, respond to both HTTP/1.<anything>
nixnax 99:3f56162e703e 644 xFetch = strncmp(dataStart, "GET /x", 6); // found GET /x , respond to both HTTP/1.<anything>
nixnax 119:e14dd2bf0ea3 645 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 93:9675adc36882 646 if( (httpGetRoot==0) || (xFetch==0) ) {
nixnax 115:b8ddff0e782f 647 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky\r\n"); // 200 OK header
nixnax 83:cdcb81d1910f 648 } else {
nixnax 89:2c8dd0c2a426 649 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 83:cdcb81d1910f 650 }
nixnax 83:cdcb81d1910f 651 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 652 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 653 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 654 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 655 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 656 nHeader=n; // size of HTTP header
nixnax 93:9675adc36882 657 if( httpGetRoot == 0 ) {
nixnax 83:cdcb81d1910f 658 // this is where we insert our web page into the buffer
nixnax 93:9675adc36882 659 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 93:9675adc36882 660 n = n + sizeof(rootWebPage);
nixnax 85:53e57ff1cf05 661 } else {
nixnax 109:644a59ebb5b1 662 if (xFetch == 0) { // the page request started with "GET /x"
nixnax 89:2c8dd0c2a426 663
nixnax 89:2c8dd0c2a426 664 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 89:2c8dd0c2a426 665 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 89:2c8dd0c2a426 666 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 106:d14e6b597ca3 667 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed-ppp-blinky</title>"); // html title (W3C.org required elements)
nixnax 98:3babad0d1bd4 668 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.httpPageCount); // body = the http frame count
nixnax 89:2c8dd0c2a426 669 #else
nixnax 109:644a59ebb5b1 670 #define BENCHMARK_USING_BROWSER_NO /* set to _YES if you want to use your browser as a benchmark tool */
nixnax 98:3babad0d1bd4 671 #ifndef BENCHMARK_USING_BROWSER_NO
nixnax 119:e14dd2bf0ea3 672 // 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 673 n=n+sprintf(n+dataStart, "<script>setTimeout(function(){location.reload();},10);</script><body>%d</body>",ppp.httpPageCount);
nixnax 98:3babad0d1bd4 674 #else
nixnax 98:3babad0d1bd4 675 n=n+sprintf(n+dataStart,"%d",ppp.httpPageCount); // not valid html but fast, most browsers and curl are ok with it
nixnax 98:3babad0d1bd4 676 #endif
nixnax 89:2c8dd0c2a426 677 #endif
nixnax 89:2c8dd0c2a426 678
nixnax 89:2c8dd0c2a426 679 } else {
nixnax 89:2c8dd0c2a426 680 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 89:2c8dd0c2a426 681 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>ppp-blinky-mbed</title>"); // html title (required element)
nixnax 89:2c8dd0c2a426 682 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 89:2c8dd0c2a426 683 }
nixnax 83:cdcb81d1910f 684 }
nixnax 87:9f5ac1fabd95 685 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 686 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 687
nixnax 83:cdcb81d1910f 688 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 689 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 690 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 691 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 692
nixnax 77:abf92baebb42 693 if (v2) {
nixnax 120:bef89e4c906e 694 // debugPrintf("HTTP Response: HTTP-header %d HTTP-content %d HTTP-total %d\n",nHeader,n-nHeader,n);
nixnax 77:abf92baebb42 695 }
nixnax 67:a63e3486bcda 696 return n; // total byte size of our response
nixnax 67:a63e3486bcda 697 }
nixnax 67:a63e3486bcda 698
nixnax 98:3babad0d1bd4 699 // if not an http response we just report the number of bytes received
nixnax 98:3babad0d1bd4 700 // this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 98:3babad0d1bd4 701 int tcpResponse(char * dataStart, int len)
nixnax 98:3babad0d1bd4 702 {
nixnax 98:3babad0d1bd4 703 int n=0; // number of bytes we have printed so far
nixnax 98:3babad0d1bd4 704 n=n+sprintf(n+dataStart,"Got %04d bytes.\n",len); // report the number of bytes received
nixnax 98:3babad0d1bd4 705 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 706 if (v2) {
nixnax 120:bef89e4c906e 707 // debugPrintf("TCP response %d bytes\n",n);
nixnax 98:3babad0d1bd4 708 }
nixnax 98:3babad0d1bd4 709 return n; // total byte size of our response
nixnax 98:3babad0d1bd4 710 }
nixnax 98:3babad0d1bd4 711
nixnax 29:30de79d658f6 712 void tcpHandler()
nixnax 29:30de79d658f6 713 {
nixnax 87:9f5ac1fabd95 714 // IP header
nixnax 119:e14dd2bf0ea3 715
nixnax 26:11f4eb2663a7 716 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 717 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 718 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 719 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 720 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 721 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 722 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 723 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 724 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 725 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 726
nixnax 87:9f5ac1fabd95 727 // TCP header
nixnax 87:9f5ac1fabd95 728
nixnax 87:9f5ac1fabd95 729 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 87:9f5ac1fabd95 730 char * srctcp = tcp + 0; // 2 bytes
nixnax 87:9f5ac1fabd95 731 char * dsttcp = tcp + 2; // 2 bytes
nixnax 87:9f5ac1fabd95 732 char * seqtcp = tcp + 4; // 4 bytes
nixnax 87:9f5ac1fabd95 733 char * acktcp = tcp + 8; // 4 bytes
nixnax 87:9f5ac1fabd95 734 char * offset = tcp + 12; // 4 bits
nixnax 87:9f5ac1fabd95 735 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 87:9f5ac1fabd95 736 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 87:9f5ac1fabd95 737 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 124:18ef53f1d8b7 738
nixnax 124:18ef53f1d8b7 739 if(ident) {}; // shut up unused variable reference warning
nixnax 26:11f4eb2663a7 740
nixnax 26:11f4eb2663a7 741 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 742 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 743 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 744
nixnax 87:9f5ac1fabd95 745 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 746 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 87:9f5ac1fabd95 747 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 81:9ede60e9a2c8 748
nixnax 85:53e57ff1cf05 749 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 85:53e57ff1cf05 750 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 85:53e57ff1cf05 751
nixnax 85:53e57ff1cf05 752 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 87:9f5ac1fabd95 753 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 81:9ede60e9a2c8 754
nixnax 29:30de79d658f6 755 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 756 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 757 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 758 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 759 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 760
nixnax 87:9f5ac1fabd95 761 // first we shorten the TCP response header to only 20 bytes.
nixnax 87:9f5ac1fabd95 762 // this means we ignore all TCP option requests
nixnax 87:9f5ac1fabd95 763
nixnax 87:9f5ac1fabd95 764 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 87:9f5ac1fabd95 765 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 87:9f5ac1fabd95 766 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 87:9f5ac1fabd95 767 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 768 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 769 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 770
nixnax 35:e7068df4d971 771 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 772 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 87:9f5ac1fabd95 773 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 92:cb962b365cce 774
nixnax 119:e14dd2bf0ea3 775 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 119:e14dd2bf0ea3 776 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 38:ab582987926e 777
nixnax 106:d14e6b597ca3 778 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 77:abf92baebb42 779
nixnax 69:23f560087c16 780 switch ( flagsTCP ) {
nixnax 69:23f560087c16 781 case TCP_FLAG_SYN:
nixnax 87:9f5ac1fabd95 782 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 119:e14dd2bf0ea3 783 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 85:53e57ff1cf05 784 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 785 break;
nixnax 77:abf92baebb42 786 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 98:3babad0d1bd4 787 if ( strncmp(tcpDataIn, "GET /", 5) == 0) { // check for an http GET command
nixnax 118:54d1936e3768 788 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 789 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 98:3babad0d1bd4 790 } else {
nixnax 106:d14e6b597ca3 791 dataLen = tcpResponse(tcpDataOut,tcpDataSize); // not a web request, send a packet reporting number of received bytes
nixnax 69:23f560087c16 792 }
nixnax 69:23f560087c16 793 break;
nixnax 116:1272e9f7ad70 794 case TCP_FLAG_FIN:
nixnax 116:1272e9f7ad70 795 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 98:3babad0d1bd4 796 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 117:c819ae068336 797 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 85:53e57ff1cf05 798 ack_out++; // for FIN flag we always have to increase sequence by 1
nixnax 69:23f560087c16 799 break;
nixnax 77:abf92baebb42 800 default:
nixnax 69:23f560087c16 801 return; // ignore remaining packets
nixnax 93:9675adc36882 802 } // switch
nixnax 77:abf92baebb42 803
nixnax 69:23f560087c16 804 // The TCP flag handling is now done
nixnax 105:45001195b325 805 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 95:40af49390daf 806
nixnax 65:23b17c43aa0f 807 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 808 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 809 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 810 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 811
nixnax 60:2b770949c911 812 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 813 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 814 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 95:40af49390daf 815
nixnax 85:53e57ff1cf05 816 acktcp[0]=ack_out>>24;
nixnax 85:53e57ff1cf05 817 acktcp[1]=ack_out>>16;
nixnax 85:53e57ff1cf05 818 acktcp[2]=ack_out>>8;
nixnax 85:53e57ff1cf05 819 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 38:ab582987926e 820
nixnax 85:53e57ff1cf05 821 seqtcp[0]=seq_out>>24;
nixnax 85:53e57ff1cf05 822 seqtcp[1]=seq_out>>16;
nixnax 85:53e57ff1cf05 823 seqtcp[2]=seq_out>>8;
nixnax 85:53e57ff1cf05 824 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 825
nixnax 93:9675adc36882 826 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 93:9675adc36882 827
nixnax 114:8a5d70bbc1b2 828 // increment our outgoing ip packet counter
nixnax 114:8a5d70bbc1b2 829 ppp.ip.ident++; // get next ident number for our packet
nixnax 124:18ef53f1d8b7 830 //ident[0] = ppp.ip.ident>>8;
nixnax 124:18ef53f1d8b7 831 //ident[1] = ppp.ip.ident>>0; // insert OUR ident
nixnax 93:9675adc36882 832
nixnax 106:d14e6b597ca3 833 // Now we recalculate all the header sizes
nixnax 38:ab582987926e 834 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 835 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 836 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 837 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 838 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 839
nixnax 38:ab582987926e 840 // the header is all set up, now do the IP and TCP checksums
nixnax 61:b3c1a04efd0a 841 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 842 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 843 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 844
nixnax 64:677b9713a120 845 // 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 846 // 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 847
nixnax 87:9f5ac1fabd95 848 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 849 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 850 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 851 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 852 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 853 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 854 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 855
nixnax 61:b3c1a04efd0a 856 // pseudo-header built, now we can calculate TCP checksum
nixnax 29:30de79d658f6 857 checksumtcp[0]=0;
nixnax 29:30de79d658f6 858 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 859 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 860 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 861 checksumtcp[1]=pseudoHeaderSum;
nixnax 87:9f5ac1fabd95 862 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 114:8a5d70bbc1b2 863 dumpHeaderIP(1); // dump outgoing IP header
nixnax 114:8a5d70bbc1b2 864 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 124:18ef53f1d8b7 865 for (int i=0; i<70*1000/10; i++) { // 70 ms delay before sending frame - a typical internet delay time
nixnax 119:e14dd2bf0ea3 866 fillbuf(); // catch any incoming characters
nixnax 124:18ef53f1d8b7 867 wait_us(10); // wait less than 1 character duration at 115200
nixnax 119:e14dd2bf0ea3 868 }
nixnax 93:9675adc36882 869 send_pppFrame(); // All preparation complete - send the TCP response
nixnax 29:30de79d658f6 870 }
nixnax 26:11f4eb2663a7 871
nixnax 29:30de79d658f6 872 void dumpDataTCP()
nixnax 29:30de79d658f6 873 {
nixnax 26:11f4eb2663a7 874 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 875 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 876 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 877 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 878 if (v1) {
nixnax 120:bef89e4c906e 879 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 880 fillbuf();
nixnax 120:bef89e4c906e 881 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 120:bef89e4c906e 882 fillbuf();
nixnax 125:ea88200b1df6 883 putsWhileCheckingInput( pbuf );
nixnax 29:30de79d658f6 884 }
nixnax 29:30de79d658f6 885 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 886 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 125:ea88200b1df6 887 putsWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP ); // print the tcp payload data
nixnax 125:ea88200b1df6 888 putsWhileCheckingInput("\n");
nixnax 29:30de79d658f6 889 }
nixnax 29:30de79d658f6 890 }
nixnax 26:11f4eb2663a7 891
nixnax 29:30de79d658f6 892 void TCPpacket()
nixnax 124:18ef53f1d8b7 893 {
nixnax 114:8a5d70bbc1b2 894 dumpHeaderIP(0); // dump incoming packet header
nixnax 114:8a5d70bbc1b2 895 dumpHeaderTCP(0); // dump incoming packet header
nixnax 77:abf92baebb42 896 if (v2) {
nixnax 77:abf92baebb42 897 dumpDataTCP();
nixnax 124:18ef53f1d8b7 898 }
nixnax 26:11f4eb2663a7 899 tcpHandler();
nixnax 11:f58998c24f0b 900 }
nixnax 11:f58998c24f0b 901
nixnax 29:30de79d658f6 902 void otherProtocol()
nixnax 29:30de79d658f6 903 {
nixnax 119:e14dd2bf0ea3 904 debugPrintf("Other IP protocol");
nixnax 29:30de79d658f6 905 }
nixnax 26:11f4eb2663a7 906
nixnax 29:30de79d658f6 907 void IPframe()
nixnax 29:30de79d658f6 908 {
nixnax 10:74f8233f72c0 909 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 910 switch (protocol) {
nixnax 29:30de79d658f6 911 case 1:
nixnax 29:30de79d658f6 912 ICMPpacket();
nixnax 29:30de79d658f6 913 break;
nixnax 29:30de79d658f6 914 case 2:
nixnax 29:30de79d658f6 915 IGMPpacket();
nixnax 29:30de79d658f6 916 break;
nixnax 29:30de79d658f6 917 case 17:
nixnax 29:30de79d658f6 918 UDPpacket();
nixnax 29:30de79d658f6 919 break;
nixnax 29:30de79d658f6 920 case 6:
nixnax 29:30de79d658f6 921 TCPpacket();
nixnax 29:30de79d658f6 922 break;
nixnax 29:30de79d658f6 923 default:
nixnax 29:30de79d658f6 924 otherProtocol();
nixnax 29:30de79d658f6 925 }
nixnax 29:30de79d658f6 926 }
nixnax 9:0992486d4a30 927
nixnax 29:30de79d658f6 928 void LCPconfReq()
nixnax 29:30de79d658f6 929 {
nixnax 119:e14dd2bf0ea3 930 debugPrintf("LCP Config ");
nixnax 9:0992486d4a30 931 if (ppp.pkt.buf[7] != 4) {
nixnax 111:6a3b77c065c0 932 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 119:e14dd2bf0ea3 933 debugPrintf("Reject\n");
nixnax 93:9675adc36882 934 send_pppFrame();
nixnax 9:0992486d4a30 935 } else {
nixnax 9:0992486d4a30 936 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 119:e14dd2bf0ea3 937 debugPrintf("Ack\n");
nixnax 93:9675adc36882 938 send_pppFrame();
nixnax 119:e14dd2bf0ea3 939 debugPrintf("LCP Ask\n");
nixnax 11:f58998c24f0b 940 ppp.pkt.buf[4]=1; // request no options
nixnax 93:9675adc36882 941 send_pppFrame();
nixnax 9:0992486d4a30 942 }
nixnax 9:0992486d4a30 943 }
nixnax 9:0992486d4a30 944
nixnax 29:30de79d658f6 945 void LCPconfAck()
nixnax 29:30de79d658f6 946 {
nixnax 119:e14dd2bf0ea3 947 debugPrintf("LCP Ack\n");
nixnax 29:30de79d658f6 948 }
nixnax 9:0992486d4a30 949
nixnax 29:30de79d658f6 950 void LCPend()
nixnax 29:30de79d658f6 951 {
nixnax 29:30de79d658f6 952 ppp.pkt.buf[4]=6;
nixnax 93:9675adc36882 953 send_pppFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 954 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 955 pppInitStruct(); // flush the receive buffer
nixnax 119:e14dd2bf0ea3 956 debugPrintf("LCP End\n");
nixnax 9:0992486d4a30 957 }
nixnax 9:0992486d4a30 958
nixnax 29:30de79d658f6 959 void LCPother()
nixnax 29:30de79d658f6 960 {
nixnax 119:e14dd2bf0ea3 961 debugPrintf("LCP Other\n");
nixnax 95:40af49390daf 962 dumpPPPFrame();
nixnax 29:30de79d658f6 963 }
nixnax 29:30de79d658f6 964
nixnax 29:30de79d658f6 965 void LCPframe()
nixnax 29:30de79d658f6 966 {
nixnax 29:30de79d658f6 967 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 968 switch (code) {
nixnax 29:30de79d658f6 969 case 1:
nixnax 29:30de79d658f6 970 LCPconfReq();
nixnax 29:30de79d658f6 971 break; // config request
nixnax 29:30de79d658f6 972 case 2:
nixnax 29:30de79d658f6 973 LCPconfAck();
nixnax 29:30de79d658f6 974 break; // config ack
nixnax 29:30de79d658f6 975 case 5:
nixnax 29:30de79d658f6 976 LCPend();
nixnax 29:30de79d658f6 977 break; // end connection
nixnax 29:30de79d658f6 978 default:
nixnax 29:30de79d658f6 979 LCPother();
nixnax 29:30de79d658f6 980 }
nixnax 9:0992486d4a30 981 }
nixnax 9:0992486d4a30 982
nixnax 29:30de79d658f6 983 void discardedFrame()
nixnax 29:30de79d658f6 984 {
nixnax 29:30de79d658f6 985 if (v0) {
nixnax 119:e14dd2bf0ea3 986 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 987 }
nixnax 9:0992486d4a30 988 }
nixnax 9:0992486d4a30 989
nixnax 29:30de79d658f6 990 void determinePacketType()
nixnax 29:30de79d658f6 991 {
nixnax 29:30de79d658f6 992 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 119:e14dd2bf0ea3 993 debugPrintf("byte0 != ff\n");
nixnax 29:30de79d658f6 994 return;
nixnax 29:30de79d658f6 995 }
nixnax 29:30de79d658f6 996 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 119:e14dd2bf0ea3 997 debugPrintf("byte1 != 3\n");
nixnax 29:30de79d658f6 998 return;
nixnax 29:30de79d658f6 999 }
nixnax 29:30de79d658f6 1000 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 119:e14dd2bf0ea3 1001 debugPrintf("byte2 != 21\n");
nixnax 29:30de79d658f6 1002 return;
nixnax 29:30de79d658f6 1003 }
nixnax 9:0992486d4a30 1004 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 1005 switch (packetType) {
nixnax 29:30de79d658f6 1006 case 0xc0:
nixnax 29:30de79d658f6 1007 LCPframe();
nixnax 29:30de79d658f6 1008 break; // link control
nixnax 29:30de79d658f6 1009 case 0x80:
nixnax 29:30de79d658f6 1010 IPCPframe();
nixnax 29:30de79d658f6 1011 break; // IP control
nixnax 29:30de79d658f6 1012 case 0x00:
nixnax 29:30de79d658f6 1013 IPframe();
nixnax 29:30de79d658f6 1014 break; // IP itself
nixnax 29:30de79d658f6 1015 default:
nixnax 29:30de79d658f6 1016 discardedFrame();
nixnax 9:0992486d4a30 1017 }
nixnax 29:30de79d658f6 1018 }
nixnax 9:0992486d4a30 1019
nixnax 119:e14dd2bf0ea3 1020 void wait_for_PPP_frame()
nixnax 50:ad4e7c3c88e5 1021 {
nixnax 85:53e57ff1cf05 1022 while(1) {
nixnax 93:9675adc36882 1023 fillbuf(); // handle received characters
nixnax 124:18ef53f1d8b7 1024 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 81:9ede60e9a2c8 1025 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 1026 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 1027 if (rx==FRAME_7E) {
nixnax 120:bef89e4c906e 1028 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 119:e14dd2bf0ea3 1029 ppp.firstFrame=0;
nixnax 120:bef89e4c906e 1030 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with virtual tail
nixnax 120:bef89e4c906e 1031 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 119:e14dd2bf0ea3 1032 } else {
nixnax 119:e14dd2bf0ea3 1033 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 119:e14dd2bf0ea3 1034 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 120:bef89e4c906e 1035 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with virtual tail
nixnax 119:e14dd2bf0ea3 1036 ppp.hdlc.frameStartIndex = ppp.rx.tail; // where next frame will start
nixnax 119:e14dd2bf0ea3 1037 break;
nixnax 119:e14dd2bf0ea3 1038 }
nixnax 50:ad4e7c3c88e5 1039 }
nixnax 50:ad4e7c3c88e5 1040 }
nixnax 85:53e57ff1cf05 1041 }
nixnax 50:ad4e7c3c88e5 1042 }
nixnax 50:ad4e7c3c88e5 1043
nixnax 29:30de79d658f6 1044 void scanForConnectString()
nixnax 29:30de79d658f6 1045 {
nixnax 81:9ede60e9a2c8 1046 while(ppp.online == 0) {
nixnax 114:8a5d70bbc1b2 1047 fillbuf(); // gather received characters
nixnax 81:9ede60e9a2c8 1048 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 106:d14e6b597ca3 1049 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 107:5fe806713d49 1050 if (found1 != NULL) {
nixnax 107:5fe806713d49 1051 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 119:e14dd2bf0ea3 1052 if (v0) debugPrintf("Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 107:5fe806713d49 1053 pc.puts("CLIENTSERVER");
nixnax 120:bef89e4c906e 1054 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 119:e14dd2bf0ea3 1055 fillbuf();
nixnax 9:0992486d4a30 1056 }
nixnax 9:0992486d4a30 1057 }
nixnax 103:4f5512dd11cf 1058 }
nixnax 81:9ede60e9a2c8 1059
nixnax 0:2cf4880c312a 1060 int main()
nixnax 0:2cf4880c312a 1061 {
nixnax 120:bef89e4c906e 1062 pc.baud(115200); // USB serial port
nixnax 120:bef89e4c906e 1063 debugBaudRate(115200); // baud rate for our debug port - if we have one
nixnax 120:bef89e4c906e 1064 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 1065 pppInitStruct(); // initialize all the PPP properties
nixnax 0:2cf4880c312a 1066 while(1) {
nixnax 120:bef89e4c906e 1067 scanForConnectString(); // wait for connect
nixnax 81:9ede60e9a2c8 1068 while(ppp.online) {
nixnax 120:bef89e4c906e 1069 wait_for_PPP_frame(); // wait for a PPP frame
nixnax 81:9ede60e9a2c8 1070 }
nixnax 7:ab147f5e97ac 1071 }
nixnax 105:45001195b325 1072 }