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@127:3ea6f776e287, 2017-08-09 (annotated)

Committer:
nixnax
Date:
Wed Aug 09 19:39:05 2017 +0000
Revision:
127:3ea6f776e287
Parent:
126:4e1058fa2128
Child:
128:e5958d143e9d
FRDM-KL46Z board added & tested.

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 127:3ea6f776e287 40 #define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
nixnax 0:2cf4880c312a 41
nixnax 93:9675adc36882 42 // here we define the OPTIONAL, second debug serial port for the various target boards
nixnax 93:9675adc36882 43 // insert your target board's port here if it's not in yet - if it works, please send it to me - thanks!!!
nixnax 114:8a5d70bbc1b2 44 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 127:3ea6f776e287 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 127:3ea6f776e287 51 #elif defined (TARGET_KL46Z)
nixnax 127:3ea6f776e287 52 Serial xx(PTE0,PTE1); // 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 118:54d1936e3768 53 #elif defined(YOUR_TARGET_BOARD_NAME_HERE)
nixnax 118:54d1936e3768 54 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 55 #else
nixnax 117:c819ae068336 56 #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 57 #endif
nixnax 119:e14dd2bf0ea3 58 #define debugPrintf(x...) xx.printf (x) /* if we have a serial port we print debug messages */
nixnax 119:e14dd2bf0ea3 59 #define debugPutc(x...) xx.putc(x)
nixnax 118:54d1936e3768 60 #define debugBaudRate(x...) xx.baud(x)
nixnax 117:c819ae068336 61 #else
nixnax 119:e14dd2bf0ea3 62 // if we don't have a debug port the debug print functions do nothing
nixnax 119:e14dd2bf0ea3 63 #define debugPrintf(x...) {}
nixnax 119:e14dd2bf0ea3 64 #define debugPutc(x...) {}
nixnax 118:54d1936e3768 65 #define debugBaudRate(x...) {}
nixnax 41:e58a5a09f411 66 #endif
nixnax 41:e58a5a09f411 67
nixnax 110:baec959e1915 68 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
nixnax 112:30172f36bd33 69 #define v0 1
nixnax 124:18ef53f1d8b7 70 #define v1 0
nixnax 77:abf92baebb42 71 #define v2 0
nixnax 114:8a5d70bbc1b2 72 #define IP_HEADER_DUMP_YES /* YES for ip header dump */
nixnax 114:8a5d70bbc1b2 73 #define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
nixnax 29:30de79d658f6 74
nixnax 93:9675adc36882 75 // this is the webpage we serve when we get an HTTP request to root (/)
nixnax 93:9675adc36882 76 // keep size under ~900 bytes to fit into a single PPP packet
nixnax 93:9675adc36882 77 const static char rootWebPage[] = "\
nixnax 66:f005b9fdf4d1 78 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 79 <html>\
nixnax 66:f005b9fdf4d1 80 <head>\
nixnax 66:f005b9fdf4d1 81 <title>mbed-PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 82 <script>\
nixnax 66:f005b9fdf4d1 83 window.onload=function(){\
nixnax 66:f005b9fdf4d1 84 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 66:f005b9fdf4d1 85 x().textContent = parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 86 </script>\
nixnax 66:f005b9fdf4d1 87 </head>\
nixnax 66:f005b9fdf4d1 88 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 89 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 90 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 91 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 92 </body>\
nixnax 69:23f560087c16 93 </html>"; // around 464 bytes long
nixnax 69:23f560087c16 94
nixnax 73:2f56ec87dbe9 95 // 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 96 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 72:ad3d12753acf 97 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 98 // See instructions at the top.
nixnax 73:2f56ec87dbe9 99 // 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 100 Serial pc(USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax 29:30de79d658f6 101
nixnax 29:30de79d658f6 102 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 103
nixnax 66:f005b9fdf4d1 104 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 105 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 106
nixnax 29:30de79d658f6 107 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 108 struct pppType {
nixnax 38:ab582987926e 109 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 110 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 111 int ledState; // state of LED1
nixnax 98:3babad0d1bd4 112 int httpPageCount;
nixnax 119:e14dd2bf0ea3 113 int firstFrame; // cleared after first frame
nixnax 4:a469050d5b80 114 struct {
nixnax 126:4e1058fa2128 115 #define RXBUFLEN (1<<11)
nixnax 117:c819ae068336 116 // the serial port receive buffer and packet buffer, size is RXBUFLEN (currently 2048 bytes)
nixnax 85:53e57ff1cf05 117 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in ring buffer
nixnax 93:9675adc36882 118 int head;
nixnax 93:9675adc36882 119 int tail;
nixnax 95:40af49390daf 120 int rtail;
nixnax 93:9675adc36882 121 int buflevel;
nixnax 38:ab582987926e 122 } rx; // serial port objects
nixnax 4:a469050d5b80 123 struct {
nixnax 38:ab582987926e 124 int len; // number of bytes in buffer
nixnax 38:ab582987926e 125 int crc; // PPP CRC (frame check)
nixnax 122:963abcbff21e 126 #define PPP_max_size 2500
nixnax 123:fc64fc6caae0 127 // we are assuming 1000 bytes more than MTU size of 1500 - due to the PPP encoding of special bytes
nixnax 122:963abcbff21e 128 char buf[PPP_max_size]; // send and receive buffer large enough for raw, encoded PPP/HDLC frames
nixnax 38:ab582987926e 129 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 130 struct {
nixnax 50:ad4e7c3c88e5 131 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 132 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 133 } hdlc; // hdlc frame objects
nixnax 114:8a5d70bbc1b2 134 struct {
nixnax 114:8a5d70bbc1b2 135 unsigned int ident; // our IP ident value (outgoing frame count)
nixnax 114:8a5d70bbc1b2 136 } ip; // ip related object
nixnax 29:30de79d658f6 137 };
nixnax 31:e000c1b9c565 138
nixnax 29:30de79d658f6 139 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 140
nixnax 93:9675adc36882 141 // Initialize our global structure, clear the buffer, etc.
nixnax 29:30de79d658f6 142 void pppInitStruct()
nixnax 29:30de79d658f6 143 {
nixnax 81:9ede60e9a2c8 144 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 29:30de79d658f6 145 ppp.online=0;
nixnax 29:30de79d658f6 146 ppp.rx.tail=0;
nixnax 93:9675adc36882 147 ppp.rx.rtail=0;
nixnax 29:30de79d658f6 148 ppp.rx.head=0;
nixnax 81:9ede60e9a2c8 149 ppp.rx.buflevel=0;
nixnax 29:30de79d658f6 150 ppp.pkt.len=0;
nixnax 114:8a5d70bbc1b2 151 ppp.ip.ident=10000; // easy to recognize in ip packet dumps
nixnax 29:30de79d658f6 152 ppp.ledState=0;
nixnax 81:9ede60e9a2c8 153 ppp.hdlc.frameStartIndex=0;
nixnax 98:3babad0d1bd4 154 ppp.httpPageCount=0;
nixnax 119:e14dd2bf0ea3 155 ppp.firstFrame=1;
nixnax 29:30de79d658f6 156 }
nixnax 26:11f4eb2663a7 157
nixnax 43:aa57db08995d 158 void led1Toggle()
nixnax 43:aa57db08995d 159 {
nixnax 43:aa57db08995d 160 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 93:9675adc36882 161 led1 = ppp.ledState; // toggle led
nixnax 43:aa57db08995d 162 }
nixnax 43:aa57db08995d 163
nixnax 85:53e57ff1cf05 164 // fill our own receive buffer with characters from the PPP serial port
nixnax 85:53e57ff1cf05 165 void fillbuf()
nixnax 0:2cf4880c312a 166 {
nixnax 107:5fe806713d49 167 char ch;
nixnax 85:53e57ff1cf05 168 if ( pc.readable() ) {
nixnax 85:53e57ff1cf05 169 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap head index
nixnax 93:9675adc36882 170 if ( hd == ppp.rx.rtail ) {
nixnax 119:e14dd2bf0ea3 171 debugPrintf("\nReceive buffer full\n");
nixnax 85:53e57ff1cf05 172 return;
nixnax 83:cdcb81d1910f 173 }
nixnax 107:5fe806713d49 174 ch = pc.getc(); // read new character
nixnax 107:5fe806713d49 175 ppp.rx.buf[ppp.rx.head] = ch; // insert in our receive buffer
nixnax 107:5fe806713d49 176 if ( ppp.online == 0 ) {
nixnax 107:5fe806713d49 177 if (ch == 0x7E) {
nixnax 107:5fe806713d49 178 ppp.online = 1;
nixnax 114:8a5d70bbc1b2 179 }
nixnax 114:8a5d70bbc1b2 180 }
nixnax 20:5db9b77b38a6 181 ppp.rx.head = hd; // update head pointer
nixnax 81:9ede60e9a2c8 182 ppp.rx.buflevel++;
nixnax 15:b0154c910143 183 }
nixnax 0:2cf4880c312a 184 }
nixnax 0:2cf4880c312a 185
nixnax 118:54d1936e3768 186 // print to debug port while checking for incoming characters
nixnax 119:e14dd2bf0ea3 187 void putcWhileCheckingInput( char outByte )
nixnax 119:e14dd2bf0ea3 188 {
nixnax 119:e14dd2bf0ea3 189 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 119:e14dd2bf0ea3 190 fillbuf();
nixnax 119:e14dd2bf0ea3 191 debugPutc( outByte );
nixnax 119:e14dd2bf0ea3 192 fillbuf();
nixnax 119:e14dd2bf0ea3 193 #endif
nixnax 119:e14dd2bf0ea3 194 }
nixnax 119:e14dd2bf0ea3 195
nixnax 125:ea88200b1df6 196 void putsWhileCheckingInput( char * data )
nixnax 118:54d1936e3768 197 {
nixnax 118:54d1936e3768 198 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 118:54d1936e3768 199 char * nextChar = data;
nixnax 118:54d1936e3768 200 while( *nextChar != 0 ) {
nixnax 119:e14dd2bf0ea3 201 putcWhileCheckingInput( *nextChar ); // write one character to debug port while checking input
nixnax 118:54d1936e3768 202 nextChar++;
nixnax 124:18ef53f1d8b7 203 }
nixnax 118:54d1936e3768 204 #endif
nixnax 118:54d1936e3768 205 }
nixnax 118:54d1936e3768 206
nixnax 124:18ef53f1d8b7 207 // a sniffer tool to assist in figuring out where in the code we are having characters in the input buffer
nixnax 124:18ef53f1d8b7 208 void qq()
nixnax 124:18ef53f1d8b7 209 {
nixnax 125:ea88200b1df6 210 if ( pc.readable() ) putsWhileCheckingInput( "Character available!\n" );
nixnax 124:18ef53f1d8b7 211 }
nixnax 124:18ef53f1d8b7 212
nixnax 118:54d1936e3768 213 void crcReset()
nixnax 118:54d1936e3768 214 {
nixnax 118:54d1936e3768 215 ppp.crc=0xffff; // crc restart
nixnax 118:54d1936e3768 216 }
nixnax 118:54d1936e3768 217
nixnax 118:54d1936e3768 218 void crcDo(int x) // cumulative crc
nixnax 118:54d1936e3768 219 {
nixnax 118:54d1936e3768 220 for (int i=0; i<8; i++) {
nixnax 118:54d1936e3768 221 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 118:54d1936e3768 222 x>>=1;
nixnax 118:54d1936e3768 223 }
nixnax 124:18ef53f1d8b7 224 fillbuf(); // handle input
nixnax 118:54d1936e3768 225 }
nixnax 118:54d1936e3768 226
nixnax 118:54d1936e3768 227 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 118:54d1936e3768 228 {
nixnax 118:54d1936e3768 229 crcReset();
nixnax 118:54d1936e3768 230 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 118:54d1936e3768 231 return ppp.crc;
nixnax 118:54d1936e3768 232 }
nixnax 118:54d1936e3768 233
nixnax 85:53e57ff1cf05 234 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 235 {
nixnax 63:9253b0e1b7d8 236 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 81:9ede60e9a2c8 237 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 81:9ede60e9a2c8 238 ppp.rx.buflevel--;
nixnax 63:9253b0e1b7d8 239 return x;
nixnax 0:2cf4880c312a 240 }
nixnax 0:2cf4880c312a 241
nixnax 95:40af49390daf 242 // Note - the hex output of dumpPPPFrame() can be imported into WireShark
nixnax 95:40af49390daf 243 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 95:40af49390daf 244 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 95:40af49390daf 245 void dumpPPPFrame()
nixnax 95:40af49390daf 246 {
nixnax 120:bef89e4c906e 247 char pbuf[30];
nixnax 120:bef89e4c906e 248 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 124:18ef53f1d8b7 249 fillbuf();
nixnax 124:18ef53f1d8b7 250 sprintf(pbuf, "%02x ", ppp.pkt.buf[i]);
nixnax 124:18ef53f1d8b7 251 fillbuf();
nixnax 125:ea88200b1df6 252 putsWhileCheckingInput(pbuf);
nixnax 124:18ef53f1d8b7 253 }
nixnax 124:18ef53f1d8b7 254 fillbuf();
nixnax 124:18ef53f1d8b7 255 sprintf(pbuf, " CRC=%04x Len=%d\n", ppp.pkt.crc, ppp.pkt.len);
nixnax 124:18ef53f1d8b7 256 fillbuf();
nixnax 125:ea88200b1df6 257 putsWhileCheckingInput(pbuf);
nixnax 95:40af49390daf 258 }
nixnax 95:40af49390daf 259
nixnax 119:e14dd2bf0ea3 260 void processPPPFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 261 {
nixnax 38:ab582987926e 262 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 263 if(start==end) {
nixnax 111:6a3b77c065c0 264 return; // empty frame
nixnax 29:30de79d658f6 265 }
nixnax 9:0992486d4a30 266 crcReset();
nixnax 9:0992486d4a30 267 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 268 ppp.pkt.len=0;
nixnax 9:0992486d4a30 269 int unstuff=0;
nixnax 17:4918c893d802 270 int idx = start;
nixnax 17:4918c893d802 271 while(1) {
nixnax 124:18ef53f1d8b7 272 fillbuf();
nixnax 9:0992486d4a30 273 if (unstuff==0) {
nixnax 72:ad3d12753acf 274 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 275 else {
nixnax 72:ad3d12753acf 276 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 277 ppp.pkt.len++;
nixnax 29:30de79d658f6 278 dest++;
nixnax 72:ad3d12753acf 279 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 280 }
nixnax 66:f005b9fdf4d1 281 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 282 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 283 ppp.pkt.len++;
nixnax 29:30de79d658f6 284 dest++;
nixnax 72:ad3d12753acf 285 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 286 unstuff=0;
nixnax 9:0992486d4a30 287 }
nixnax 81:9ede60e9a2c8 288 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 289 if (idx == end) break;
nixnax 9:0992486d4a30 290 }
nixnax 29:30de79d658f6 291 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 120:bef89e4c906e 292 if(0) dumpPPPFrame(); // set to 1 to dump ALL ppp frames
nixnax 9:0992486d4a30 293 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 294 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 295 determinePacketType();
nixnax 90:55e0f243a7ce 296 } else {
nixnax 124:18ef53f1d8b7 297 #ifdef REPORT_FCS_ERROR_YES
nixnax 118:54d1936e3768 298 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 299 fillbuf();
nixnax 124:18ef53f1d8b7 300 sprintf(pbuf, "\nPPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // print a debug line
nixnax 120:bef89e4c906e 301 fillbuf();
nixnax 125:ea88200b1df6 302 putsWhileCheckingInput( pbuf );
nixnax 120:bef89e4c906e 303 if(0) dumpPPPFrame(); // set to 1 to dump frames with errors in them
nixnax 124:18ef53f1d8b7 304 #endif
nixnax 9:0992486d4a30 305 }
nixnax 9:0992486d4a30 306 }
nixnax 9:0992486d4a30 307
nixnax 124:18ef53f1d8b7 308 void pcPutcWhileCheckingInput(int ch)
nixnax 124:18ef53f1d8b7 309 {
nixnax 124:18ef53f1d8b7 310 fillbuf(); // check input
nixnax 124:18ef53f1d8b7 311 pc.putc(ch);
nixnax 124:18ef53f1d8b7 312 fillbuf();
nixnax 124:18ef53f1d8b7 313 }
nixnax 124:18ef53f1d8b7 314
nixnax 29:30de79d658f6 315 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 316 {
nixnax 29:30de79d658f6 317 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 124:18ef53f1d8b7 318 pcPutcWhileCheckingInput(0x7d);
nixnax 124:18ef53f1d8b7 319 pcPutcWhileCheckingInput(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 320 } else {
nixnax 124:18ef53f1d8b7 321 pcPutcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 322 }
nixnax 11:f58998c24f0b 323 }
nixnax 9:0992486d4a30 324
nixnax 93:9675adc36882 325 void send_pppFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 326 {
nixnax 17:4918c893d802 327 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 328 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 329 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 124:18ef53f1d8b7 330 pcPutcWhileCheckingInput(0x7e); // hdlc start-of-frame "flag"
nixnax 95:40af49390daf 331 for(int i=0; i<ppp.pkt.len; i++) {
nixnax 93:9675adc36882 332 hdlcPut( ppp.pkt.buf[i] ); // send a character
nixnax 93:9675adc36882 333 }
nixnax 124:18ef53f1d8b7 334 pcPutcWhileCheckingInput(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 335 }
nixnax 9:0992486d4a30 336
nixnax 93:9675adc36882 337 void ipcpConfigRequestHandler()
nixnax 29:30de79d658f6 338 {
nixnax 119:e14dd2bf0ea3 339 debugPrintf("Their IPCP Config Req, Our Ack\n");
nixnax 92:cb962b365cce 340 ppp.pkt.buf[4]=2; // change code to ack
nixnax 108:f77ec4605945 341 send_pppFrame(); // acknowledge everything they ask for - assume it's IP addresses
nixnax 106:d14e6b597ca3 342
nixnax 119:e14dd2bf0ea3 343 debugPrintf("Our IPCP Ask (no options)\n");
nixnax 92:cb962b365cce 344 ppp.pkt.buf[4]=1; // change code to request
nixnax 106:d14e6b597ca3 345 ppp.pkt.buf[7]=4; // no options in this request
nixnax 106:d14e6b597ca3 346 ppp.pkt.len=10; // no options in this request shortest ipcp packet possible (4 ppp + 4 ipcp + 2 crc)
nixnax 124:18ef53f1d8b7 347 send_pppFrame(); // send our request
nixnax 9:0992486d4a30 348 }
nixnax 9:0992486d4a30 349
nixnax 93:9675adc36882 350 void ipcpAckHandler()
nixnax 29:30de79d658f6 351 {
nixnax 119:e14dd2bf0ea3 352 debugPrintf("Their IPCP Grant\n");
nixnax 29:30de79d658f6 353 }
nixnax 9:0992486d4a30 354
nixnax 93:9675adc36882 355 void ipcpNackHandler()
nixnax 29:30de79d658f6 356 {
nixnax 119:e14dd2bf0ea3 357 debugPrintf("Their IPCP Nack, Our ACK\n");
nixnax 107:5fe806713d49 358 if (ppp.pkt.buf[8]==3) { // check if the NACK contains an IP address parameter
nixnax 106:d14e6b597ca3 359 ppp.pkt.buf[4]=1; // assume the NACK contains our "suggested" IP address
nixnax 106:d14e6b597ca3 360 send_pppFrame(); // let's request this IP address as ours
nixnax 106:d14e6b597ca3 361 } // if it's not an IP nack we ignore it
nixnax 29:30de79d658f6 362 }
nixnax 9:0992486d4a30 363
nixnax 93:9675adc36882 364 void ipcpDefaultHandler()
nixnax 29:30de79d658f6 365 {
nixnax 119:e14dd2bf0ea3 366 debugPrintf("Their IPCP Other\n");
nixnax 29:30de79d658f6 367 }
nixnax 29:30de79d658f6 368
nixnax 29:30de79d658f6 369 void IPCPframe()
nixnax 29:30de79d658f6 370 {
nixnax 9:0992486d4a30 371 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 372 switch (code) {
nixnax 29:30de79d658f6 373 case 1:
nixnax 93:9675adc36882 374 ipcpConfigRequestHandler();
nixnax 29:30de79d658f6 375 break;
nixnax 29:30de79d658f6 376 case 2:
nixnax 93:9675adc36882 377 ipcpAckHandler();
nixnax 29:30de79d658f6 378 break;
nixnax 29:30de79d658f6 379 case 3:
nixnax 93:9675adc36882 380 ipcpNackHandler();
nixnax 29:30de79d658f6 381 break;
nixnax 29:30de79d658f6 382 default:
nixnax 93:9675adc36882 383 ipcpDefaultHandler();
nixnax 9:0992486d4a30 384 }
nixnax 29:30de79d658f6 385 }
nixnax 9:0992486d4a30 386
nixnax 29:30de79d658f6 387 void UDPpacket()
nixnax 29:30de79d658f6 388 {
nixnax 12:db0dc91f0231 389 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 390 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 391 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 118:54d1936e3768 392 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 393 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 394 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 395 #endif
nixnax 12:db0dc91f0231 396 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 397 char * udpInf = udpBlock+8; // actual start of info
nixnax 118:54d1936e3768 398 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 12:db0dc91f0231 399 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 400 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 401 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 402 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 403 #endif
nixnax 29:30de79d658f6 404 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 405 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 119:e14dd2bf0ea3 406 if(v0) debugPrintf("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 119:e14dd2bf0ea3 407 if(v0) debugPrintf("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 119:e14dd2bf0ea3 408 if(v0) debugPrintf("Len %03d", udpLength);
nixnax 29:30de79d658f6 409 int printSize = udpLength;
nixnax 29:30de79d658f6 410 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 411 if (v1) {
nixnax 29:30de79d658f6 412 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 413 char ch = udpInf[i];
nixnax 29:30de79d658f6 414 if (ch>31 && ch<127) {
nixnax 119:e14dd2bf0ea3 415 debugPrintf("%c", ch);
nixnax 29:30de79d658f6 416 } else {
nixnax 119:e14dd2bf0ea3 417 debugPrintf("_");
nixnax 29:30de79d658f6 418 }
nixnax 29:30de79d658f6 419 }
nixnax 29:30de79d658f6 420 }
nixnax 119:e14dd2bf0ea3 421 if (v0) debugPrintf("\n");
nixnax 12:db0dc91f0231 422 }
nixnax 11:f58998c24f0b 423
nixnax 76:00e208cceb8b 424 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 425 {
nixnax 75:0d513869231f 426 unsigned int sum=0;
nixnax 76:00e208cceb8b 427 unsigned char placeHolder;
nixnax 29:30de79d658f6 428 if (len&1) {
nixnax 76:00e208cceb8b 429 placeHolder = ptr[len]; // when length is odd stuff in a zero byte
nixnax 76:00e208cceb8b 430 ptr[len]=0;
nixnax 29:30de79d658f6 431 }
nixnax 29:30de79d658f6 432 for (int i=0; i<len/2; i++) {
nixnax 124:18ef53f1d8b7 433 fillbuf();
nixnax 76:00e208cceb8b 434 unsigned int hi = *ptr;
nixnax 29:30de79d658f6 435 ptr++;
nixnax 76:00e208cceb8b 436 unsigned int lo = *ptr;
nixnax 29:30de79d658f6 437 ptr++;
nixnax 76:00e208cceb8b 438 unsigned int val = ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 439 sum = sum + val;
nixnax 11:f58998c24f0b 440 }
nixnax 29:30de79d658f6 441 if (len&1) {
nixnax 76:00e208cceb8b 442 ptr[len] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 443 }
nixnax 76:00e208cceb8b 444 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 445 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 446 return ~sum;
nixnax 29:30de79d658f6 447 }
nixnax 11:f58998c24f0b 448
nixnax 29:30de79d658f6 449 void headerCheckSum()
nixnax 29:30de79d658f6 450 {
nixnax 11:f58998c24f0b 451 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 452 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 453 int sum=0;
nixnax 11:f58998c24f0b 454
nixnax 29:30de79d658f6 455 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 456 int hi = *ptr;
nixnax 29:30de79d658f6 457 ptr++;
nixnax 29:30de79d658f6 458 int lo = *ptr;
nixnax 29:30de79d658f6 459 ptr++;
nixnax 11:f58998c24f0b 460 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 461 sum = sum + val;
nixnax 124:18ef53f1d8b7 462 fillbuf();
nixnax 11:f58998c24f0b 463 }
nixnax 11:f58998c24f0b 464 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 465 sum = ~sum;
nixnax 11:f58998c24f0b 466 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 467 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 468 }
nixnax 9:0992486d4a30 469
nixnax 29:30de79d658f6 470 void ICMPpacket() // internet control message protocol
nixnax 124:18ef53f1d8b7 471 {
nixnax 12:db0dc91f0231 472 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 473 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 474 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 475 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 476 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 477 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 478 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 479 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 480 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 481 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 482 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 483 char * dstAdr = ipPkt+16;
nixnax 124:18ef53f1d8b7 484 #ifdef SERIAL_PORT_MONITOR_YES
nixnax 18:3e35de1bc877 485 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 486 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 125:ea88200b1df6 487 if(1) {
nixnax 124:18ef53f1d8b7 488 char pbuf[50];
nixnax 124:18ef53f1d8b7 489 fillbuf();
nixnax 124:18ef53f1d8b7 490 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 491 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 492 fillbuf();
nixnax 125:ea88200b1df6 493 sprintf(pbuf, "Ident %04x Sequence %04d \n",icmpIdent,icmpSequence);
nixnax 124:18ef53f1d8b7 494 fillbuf();
nixnax 125:ea88200b1df6 495 putsWhileCheckingInput( pbuf );
nixnax 124:18ef53f1d8b7 496 }
nixnax 124:18ef53f1d8b7 497 #endif
nixnax 29:30de79d658f6 498 char src[4];
nixnax 29:30de79d658f6 499 char dst[4];
nixnax 12:db0dc91f0231 500 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 501 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 502 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 503 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 504 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 505 chkSum[0]=0;
nixnax 29:30de79d658f6 506 chkSum[1]=0;
nixnax 12:db0dc91f0231 507 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 508 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 509 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 510 icmpSum[0]=0;
nixnax 29:30de79d658f6 511 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 512 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 513 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 514 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 515 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 516
nixnax 16:cb0b80c24ba2 517 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 518 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 519 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 124:18ef53f1d8b7 520 if (0) {
nixnax 29:30de79d658f6 521 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 522 char ch = icmpData[i];
nixnax 29:30de79d658f6 523 if (ch>31 && ch<127) {
nixnax 124:18ef53f1d8b7 524 putcWhileCheckingInput(ch);
nixnax 29:30de79d658f6 525 } else {
nixnax 124:18ef53f1d8b7 526 putcWhileCheckingInput('_');
nixnax 29:30de79d658f6 527 }
nixnax 29:30de79d658f6 528 }
nixnax 124:18ef53f1d8b7 529 putcWhileCheckingInput('\n');
nixnax 29:30de79d658f6 530 }
nixnax 93:9675adc36882 531 send_pppFrame(); // reply to the ping
nixnax 12:db0dc91f0231 532 } else {
nixnax 29:30de79d658f6 533 if (v0) {
nixnax 119:e14dd2bf0ea3 534 debugPrintf("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 535 }
nixnax 124:18ef53f1d8b7 536 }
nixnax 11:f58998c24f0b 537 }
nixnax 11:f58998c24f0b 538
nixnax 29:30de79d658f6 539 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 540 {
nixnax 119:e14dd2bf0ea3 541 if (v0) debugPrintf("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 542 }
nixnax 11:f58998c24f0b 543
nixnax 114:8a5d70bbc1b2 544 void dumpHeaderIP (int outGoing)
nixnax 29:30de79d658f6 545 {
nixnax 114:8a5d70bbc1b2 546 #if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 119:e14dd2bf0ea3 547 fillbuf(); // we are expecting the first character of the next packet
nixnax 114:8a5d70bbc1b2 548 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 114:8a5d70bbc1b2 549 char * ident = ipPkt+4; // 2 bytes
nixnax 118:54d1936e3768 550 #ifdef UNUSED_IP_VARIABLES
nixnax 114:8a5d70bbc1b2 551 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 114:8a5d70bbc1b2 552 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 114:8a5d70bbc1b2 553 char * version = ipPkt; // top 4 bits
nixnax 114:8a5d70bbc1b2 554 char * ihl = ipPkt; // bottom 4 bits
nixnax 114:8a5d70bbc1b2 555 char * dscp = ipPkt+1; // top 6 bits
nixnax 114:8a5d70bbc1b2 556 char * ecn = ipPkt+1; // lower 2 bits
nixnax 114:8a5d70bbc1b2 557 char * pktLen = ipPkt+2; // 2 bytes
nixnax 114:8a5d70bbc1b2 558 char * flags = ipPkt+6; // 2 bits
nixnax 114:8a5d70bbc1b2 559 char * ttl = ipPkt+8; // 1 byte
nixnax 114:8a5d70bbc1b2 560 char * protocol = ipPkt+9; // 1 byte
nixnax 114:8a5d70bbc1b2 561 char * headercheck= ipPkt+10; // 2 bytes
nixnax 114:8a5d70bbc1b2 562 int versionIP = (version[0]>>4)&0xf;
nixnax 114:8a5d70bbc1b2 563 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 114:8a5d70bbc1b2 564 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 114:8a5d70bbc1b2 565 int ecnIP = ecn[0]&3;
nixnax 114:8a5d70bbc1b2 566 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 114:8a5d70bbc1b2 567 int flagsIP = flags[0]>>14&3;
nixnax 114:8a5d70bbc1b2 568 int ttlIP = ttl[0];
nixnax 114:8a5d70bbc1b2 569 int protocolIP = protocol[0];
nixnax 114:8a5d70bbc1b2 570 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 571 #endif
nixnax 119:e14dd2bf0ea3 572 int IPv4Id = (ident[0]<<8)|ident[1];
nixnax 119:e14dd2bf0ea3 573 char pbuf[50]; // local print buffer
nixnax 118:54d1936e3768 574 int n=0;
nixnax 119:e14dd2bf0ea3 575 n=n+sprintf(pbuf+n, outGoing ? "\x1b[34m" : "\x1b[30m" ); // VT100 color code, print black for incoming, blue for outgoing headers
nixnax 119:e14dd2bf0ea3 576 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 577 #define DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 578 #ifdef DUMP_FULL_IP_ADDRESS_YES
nixnax 119:e14dd2bf0ea3 579 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 119:e14dd2bf0ea3 580 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 119:e14dd2bf0ea3 581 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 582 #endif
nixnax 125:ea88200b1df6 583 putsWhileCheckingInput( pbuf );
nixnax 114:8a5d70bbc1b2 584 #ifndef TCP_HEADER_DUMP_YES
nixnax 125:ea88200b1df6 585 putsWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
nixnax 114:8a5d70bbc1b2 586 #endif
nixnax 114:8a5d70bbc1b2 587 #endif
nixnax 29:30de79d658f6 588 }
nixnax 26:11f4eb2663a7 589
nixnax 114:8a5d70bbc1b2 590 void dumpHeaderTCP(int outGoing)
nixnax 29:30de79d658f6 591 {
nixnax 114:8a5d70bbc1b2 592 #if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
nixnax 114:8a5d70bbc1b2 593 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 114:8a5d70bbc1b2 594 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 114:8a5d70bbc1b2 595 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 114:8a5d70bbc1b2 596 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 114:8a5d70bbc1b2 597 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 114:8a5d70bbc1b2 598 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 114:8a5d70bbc1b2 599 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 114:8a5d70bbc1b2 600 if (seq && ack) {} // shut up the compiler about unused variables
nixnax 114:8a5d70bbc1b2 601 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 602
nixnax 119:e14dd2bf0ea3 603 char flagInfo[9]; // text string presenting the 8 most important TCP flags
nixnax 119:e14dd2bf0ea3 604 #define PRINT_ALL_TCP_FLAGS_YES
nixnax 119:e14dd2bf0ea3 605 #ifdef PRINT_ALL_TCP_FLAGS_YES
nixnax 114:8a5d70bbc1b2 606 memset(flagInfo,'.', 8); // fill string with "........"
nixnax 114:8a5d70bbc1b2 607 flagInfo[8]=0; // null terminate string
nixnax 114:8a5d70bbc1b2 608 if (flags & (1<<0)) flagInfo[7]='F';
nixnax 114:8a5d70bbc1b2 609 if (flags & (1<<1)) flagInfo[6]='S';
nixnax 114:8a5d70bbc1b2 610 if (flags & (1<<2)) flagInfo[5]='R';
nixnax 114:8a5d70bbc1b2 611 if (flags & (1<<3)) flagInfo[4]='P';
nixnax 114:8a5d70bbc1b2 612 if (flags & (1<<4)) flagInfo[3]='A';
nixnax 114:8a5d70bbc1b2 613 if (flags & (1<<5)) flagInfo[2]='U';
nixnax 114:8a5d70bbc1b2 614 if (flags & (1<<6)) flagInfo[1]='E';
nixnax 114:8a5d70bbc1b2 615 if (flags & (1<<7)) flagInfo[0]='C';
nixnax 118:54d1936e3768 616 #else
nixnax 119:e14dd2bf0ea3 617 if (flags & (1<<4)) flagInfo[0]='A'; // choose the most important flag to print
nixnax 119:e14dd2bf0ea3 618 if (flags & (1<<1)) flagInfo[0]='S';
nixnax 119:e14dd2bf0ea3 619 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 119:e14dd2bf0ea3 620 if (flags & (1<<3)) flagInfo[0]='P';
nixnax 119:e14dd2bf0ea3 621 if (flags & (1<<2)) flagInfo[0]='R';
nixnax 124:18ef53f1d8b7 622 flagInfo[1]=0; // ' '
nixnax 119:e14dd2bf0ea3 623 flagInfo[2]=0;
nixnax 118:54d1936e3768 624 #endif
nixnax 125:ea88200b1df6 625 putsWhileCheckingInput( flagInfo );
nixnax 119:e14dd2bf0ea3 626 #define EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 119:e14dd2bf0ea3 627 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
nixnax 125:ea88200b1df6 628 putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
nixnax 119:e14dd2bf0ea3 629 #endif
nixnax 119:e14dd2bf0ea3 630 if( outGoing && ( flags == 0x11 ) ) { // ACK/FIN - if this is an outgoing ACK/FIN its the end of a tcp conversation
nixnax 119:e14dd2bf0ea3 631 putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP the conversation
nixnax 118:54d1936e3768 632 }
nixnax 114:8a5d70bbc1b2 633 #endif
nixnax 29:30de79d658f6 634 }
nixnax 29:30de79d658f6 635
nixnax 68:0b74763ae67f 636 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 637 {
nixnax 67:a63e3486bcda 638 int n=0; // number of bytes we have printed so far
nixnax 77:abf92baebb42 639 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 640 int contentLengthStart; // index where HTML starts
nixnax 93:9675adc36882 641 int xFetch, httpGetRoot; // temporary storage of strncmp results
nixnax 85:53e57ff1cf05 642
nixnax 98:3babad0d1bd4 643 ppp.httpPageCount++; // increment the number of frames we have made
nixnax 85:53e57ff1cf05 644
nixnax 98:3babad0d1bd4 645 httpGetRoot = strncmp(dataStart, "GET / HTTP/1.", 13); // found GET, respond to both HTTP/1.<anything>
nixnax 99:3f56162e703e 646 xFetch = strncmp(dataStart, "GET /x", 6); // found GET /x , respond to both HTTP/1.<anything>
nixnax 119:e14dd2bf0ea3 647 // for example, you could try this using netcat (nc): echo "GET /x" | nc 172.10.10.2
nixnax 93:9675adc36882 648 if( (httpGetRoot==0) || (xFetch==0) ) {
nixnax 115:b8ddff0e782f 649 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky\r\n"); // 200 OK header
nixnax 83:cdcb81d1910f 650 } else {
nixnax 89:2c8dd0c2a426 651 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
nixnax 83:cdcb81d1910f 652 }
nixnax 83:cdcb81d1910f 653 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 654 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 655 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 656 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 657 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 658 nHeader=n; // size of HTTP header
nixnax 93:9675adc36882 659 if( httpGetRoot == 0 ) {
nixnax 83:cdcb81d1910f 660 // this is where we insert our web page into the buffer
nixnax 93:9675adc36882 661 memcpy(n+dataStart,rootWebPage,sizeof(rootWebPage));
nixnax 93:9675adc36882 662 n = n + sizeof(rootWebPage);
nixnax 85:53e57ff1cf05 663 } else {
nixnax 109:644a59ebb5b1 664 if (xFetch == 0) { // the page request started with "GET /x"
nixnax 89:2c8dd0c2a426 665
nixnax 89:2c8dd0c2a426 666 #define W3C_COMPLIANT_RESPONSE_NO
nixnax 89:2c8dd0c2a426 667 // change the above to W3C_COMPLIANT_RESPONSE_YES if you want a W3C.org compliant HTTP response
nixnax 89:2c8dd0c2a426 668 #ifdef W3C_COMPLIANT_RESPONSE_YES
nixnax 106:d14e6b597ca3 669 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>mbed-ppp-blinky</title>"); // html title (W3C.org required elements)
nixnax 98:3babad0d1bd4 670 n=n+sprintf(n+dataStart,"<body>%d</body>",ppp.httpPageCount); // body = the http frame count
nixnax 89:2c8dd0c2a426 671 #else
nixnax 109:644a59ebb5b1 672 #define BENCHMARK_USING_BROWSER_NO /* set to _YES if you want to use your browser as a benchmark tool */
nixnax 98:3babad0d1bd4 673 #ifndef BENCHMARK_USING_BROWSER_NO
nixnax 119:e14dd2bf0ea3 674 // 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 675 n=n+sprintf(n+dataStart, "<script>setTimeout(function(){location.reload();},10);</script><body>%d</body>",ppp.httpPageCount);
nixnax 98:3babad0d1bd4 676 #else
nixnax 98:3babad0d1bd4 677 n=n+sprintf(n+dataStart,"%d",ppp.httpPageCount); // not valid html but fast, most browsers and curl are ok with it
nixnax 98:3babad0d1bd4 678 #endif
nixnax 89:2c8dd0c2a426 679 #endif
nixnax 89:2c8dd0c2a426 680
nixnax 89:2c8dd0c2a426 681 } else {
nixnax 89:2c8dd0c2a426 682 // all other requests get 404 Not Found response with a http frame count - nice for debugging
nixnax 89:2c8dd0c2a426 683 n=n+sprintf(n+dataStart,"<!DOCTYPE html><title>ppp-blinky-mbed</title>"); // html title (required element)
nixnax 89:2c8dd0c2a426 684 n=n+sprintf(n+dataStart,"<body>Not Found</body>"); // not found message
nixnax 89:2c8dd0c2a426 685 }
nixnax 83:cdcb81d1910f 686 }
nixnax 87:9f5ac1fabd95 687 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 688 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 689
nixnax 83:cdcb81d1910f 690 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 691 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 692 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 693 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 694
nixnax 77:abf92baebb42 695 if (v2) {
nixnax 120:bef89e4c906e 696 // debugPrintf("HTTP Response: HTTP-header %d HTTP-content %d HTTP-total %d\n",nHeader,n-nHeader,n);
nixnax 77:abf92baebb42 697 }
nixnax 67:a63e3486bcda 698 return n; // total byte size of our response
nixnax 67:a63e3486bcda 699 }
nixnax 67:a63e3486bcda 700
nixnax 98:3babad0d1bd4 701 // if not an http response we just report the number of bytes received
nixnax 98:3babad0d1bd4 702 // this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
nixnax 98:3babad0d1bd4 703 int tcpResponse(char * dataStart, int len)
nixnax 98:3babad0d1bd4 704 {
nixnax 98:3babad0d1bd4 705 int n=0; // number of bytes we have printed so far
nixnax 98:3babad0d1bd4 706 n=n+sprintf(n+dataStart,"Got %04d bytes.\n",len); // report the number of bytes received
nixnax 98:3babad0d1bd4 707 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 708 if (v2) {
nixnax 120:bef89e4c906e 709 // debugPrintf("TCP response %d bytes\n",n);
nixnax 98:3babad0d1bd4 710 }
nixnax 98:3babad0d1bd4 711 return n; // total byte size of our response
nixnax 98:3babad0d1bd4 712 }
nixnax 98:3babad0d1bd4 713
nixnax 29:30de79d658f6 714 void tcpHandler()
nixnax 29:30de79d658f6 715 {
nixnax 87:9f5ac1fabd95 716 // IP header
nixnax 119:e14dd2bf0ea3 717
nixnax 26:11f4eb2663a7 718 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 719 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 720 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 721 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 722 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 723 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 724 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 725 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 726 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 727 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 728
nixnax 87:9f5ac1fabd95 729 // TCP header
nixnax 87:9f5ac1fabd95 730
nixnax 87:9f5ac1fabd95 731 char * tcp = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 87:9f5ac1fabd95 732 char * srctcp = tcp + 0; // 2 bytes
nixnax 87:9f5ac1fabd95 733 char * dsttcp = tcp + 2; // 2 bytes
nixnax 87:9f5ac1fabd95 734 char * seqtcp = tcp + 4; // 4 bytes
nixnax 87:9f5ac1fabd95 735 char * acktcp = tcp + 8; // 4 bytes
nixnax 87:9f5ac1fabd95 736 char * offset = tcp + 12; // 4 bits
nixnax 87:9f5ac1fabd95 737 char * flagbitstcp = tcp + 12; // 9 bits
nixnax 87:9f5ac1fabd95 738 char * windowsizetcp = tcp + 14; // 2 bytes
nixnax 87:9f5ac1fabd95 739 char * checksumtcp = tcp + 16; // 2 bytes
nixnax 124:18ef53f1d8b7 740
nixnax 124:18ef53f1d8b7 741 if(ident) {}; // shut up unused variable reference warning
nixnax 26:11f4eb2663a7 742
nixnax 26:11f4eb2663a7 743 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 744 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 745 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 746
nixnax 87:9f5ac1fabd95 747 char * tcpDataIn = tcp + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 748 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 87:9f5ac1fabd95 749 char * tcpDataOut = tcp + 20; // start of outgoing data
nixnax 81:9ede60e9a2c8 750
nixnax 85:53e57ff1cf05 751 unsigned int seq_in = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 85:53e57ff1cf05 752 unsigned int ack_in = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 85:53e57ff1cf05 753
nixnax 85:53e57ff1cf05 754 unsigned int ack_out = seq_in + tcpDataSize;
nixnax 87:9f5ac1fabd95 755 unsigned int seq_out = ack_in; // use their version of our current sequence number
nixnax 81:9ede60e9a2c8 756
nixnax 29:30de79d658f6 757 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 758 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 759 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 760 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 761 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 762
nixnax 87:9f5ac1fabd95 763 // first we shorten the TCP response header to only 20 bytes.
nixnax 87:9f5ac1fabd95 764 // this means we ignore all TCP option requests
nixnax 87:9f5ac1fabd95 765
nixnax 87:9f5ac1fabd95 766 tcpSize = 20; // shorten total TCP packet size to 20 bytes (no data)
nixnax 87:9f5ac1fabd95 767 headerSizeTCP = 20; // shorten outgoing TCP header size 20 bytes
nixnax 87:9f5ac1fabd95 768 offset[0] = (headerSizeTCP/4)<<4; // shorten tcp header size to 20 bytes
nixnax 87:9f5ac1fabd95 769 packetLength = 40; // shorten total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 770 pktLen[1] = 40; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 771 pktLen[0] = 0; // set total packet size to 40 bytes (20 ip + 20 tcp)
nixnax 87:9f5ac1fabd95 772
nixnax 35:e7068df4d971 773 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 774 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 87:9f5ac1fabd95 775 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
nixnax 92:cb962b365cce 776
nixnax 119:e14dd2bf0ea3 777 windowsizetcp[0] = (700 >> 8 ); // tcp window size hi byte
nixnax 119:e14dd2bf0ea3 778 windowsizetcp[1] = (700 & 0xff); // tcp window size lo byte
nixnax 38:ab582987926e 779
nixnax 106:d14e6b597ca3 780 // A sparse TCP flag interpreter that implements stateless TCP connections
nixnax 77:abf92baebb42 781
nixnax 69:23f560087c16 782 switch ( flagsTCP ) {
nixnax 69:23f560087c16 783 case TCP_FLAG_SYN:
nixnax 87:9f5ac1fabd95 784 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
nixnax 119:e14dd2bf0ea3 785 seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a starting point, increase the highest digit
nixnax 85:53e57ff1cf05 786 ack_out++; // for SYN flag we have to increase the sequence by 1
nixnax 69:23f560087c16 787 break;
nixnax 77:abf92baebb42 788 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 98:3babad0d1bd4 789 if ( strncmp(tcpDataIn, "GET /", 5) == 0) { // check for an http GET command
nixnax 118:54d1936e3768 790 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 791 dataLen = httpResponse(tcpDataOut); // send an http response
nixnax 98:3babad0d1bd4 792 } else {
nixnax 106:d14e6b597ca3 793 dataLen = tcpResponse(tcpDataOut,tcpDataSize); // not a web request, send a packet reporting number of received bytes
nixnax 69:23f560087c16 794 }
nixnax 69:23f560087c16 795 break;
nixnax 116:1272e9f7ad70 796 case TCP_FLAG_FIN:
nixnax 116:1272e9f7ad70 797 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 98:3babad0d1bd4 798 case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
nixnax 117:c819ae068336 799 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // set outgoing FIN flag to ask them to close from their side
nixnax 85:53e57ff1cf05 800 ack_out++; // for FIN flag we always have to increase sequence by 1
nixnax 69:23f560087c16 801 break;
nixnax 77:abf92baebb42 802 default:
nixnax 69:23f560087c16 803 return; // ignore remaining packets
nixnax 93:9675adc36882 804 } // switch
nixnax 77:abf92baebb42 805
nixnax 69:23f560087c16 806 // The TCP flag handling is now done
nixnax 105:45001195b325 807 // first we swap source and destination TCP addresses and insert the new ack and seq numbers
nixnax 95:40af49390daf 808
nixnax 65:23b17c43aa0f 809 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 810 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 811 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 812 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 813
nixnax 60:2b770949c911 814 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 815 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 816 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 95:40af49390daf 817
nixnax 85:53e57ff1cf05 818 acktcp[0]=ack_out>>24;
nixnax 85:53e57ff1cf05 819 acktcp[1]=ack_out>>16;
nixnax 85:53e57ff1cf05 820 acktcp[2]=ack_out>>8;
nixnax 85:53e57ff1cf05 821 acktcp[3]=ack_out>>0; // save ack 32-bit integer
nixnax 38:ab582987926e 822
nixnax 85:53e57ff1cf05 823 seqtcp[0]=seq_out>>24;
nixnax 85:53e57ff1cf05 824 seqtcp[1]=seq_out>>16;
nixnax 85:53e57ff1cf05 825 seqtcp[2]=seq_out>>8;
nixnax 85:53e57ff1cf05 826 seqtcp[3]=seq_out>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 827
nixnax 93:9675adc36882 828 flagbitstcp[1] = flagsOut; // update the TCP flags
nixnax 93:9675adc36882 829
nixnax 114:8a5d70bbc1b2 830 // increment our outgoing ip packet counter
nixnax 114:8a5d70bbc1b2 831 ppp.ip.ident++; // get next ident number for our packet
nixnax 124:18ef53f1d8b7 832 //ident[0] = ppp.ip.ident>>8;
nixnax 124:18ef53f1d8b7 833 //ident[1] = ppp.ip.ident>>0; // insert OUR ident
nixnax 93:9675adc36882 834
nixnax 106:d14e6b597ca3 835 // Now we recalculate all the header sizes
nixnax 38:ab582987926e 836 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 837 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 838 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 839 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 840 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 841
nixnax 38:ab582987926e 842 // the header is all set up, now do the IP and TCP checksums
nixnax 61:b3c1a04efd0a 843 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 844 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 845 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 846
nixnax 64:677b9713a120 847 // 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 848 // 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 849
nixnax 87:9f5ac1fabd95 850 char * pseudoHeader = tcp-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 851 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 852 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 853 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 854 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 855 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 856 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 857
nixnax 61:b3c1a04efd0a 858 // pseudo-header built, now we can calculate TCP checksum
nixnax 29:30de79d658f6 859 checksumtcp[0]=0;
nixnax 29:30de79d658f6 860 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 861 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 862 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 863 checksumtcp[1]=pseudoHeaderSum;
nixnax 87:9f5ac1fabd95 864 memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 114:8a5d70bbc1b2 865 dumpHeaderIP(1); // dump outgoing IP header
nixnax 114:8a5d70bbc1b2 866 dumpHeaderTCP(1); // dump outgoing TCP header
nixnax 124:18ef53f1d8b7 867 for (int i=0; i<70*1000/10; i++) { // 70 ms delay before sending frame - a typical internet delay time
nixnax 119:e14dd2bf0ea3 868 fillbuf(); // catch any incoming characters
nixnax 124:18ef53f1d8b7 869 wait_us(10); // wait less than 1 character duration at 115200
nixnax 119:e14dd2bf0ea3 870 }
nixnax 93:9675adc36882 871 send_pppFrame(); // All preparation complete - send the TCP response
nixnax 29:30de79d658f6 872 }
nixnax 26:11f4eb2663a7 873
nixnax 29:30de79d658f6 874 void dumpDataTCP()
nixnax 29:30de79d658f6 875 {
nixnax 26:11f4eb2663a7 876 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 877 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 878 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 879 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 880 if (v1) {
nixnax 120:bef89e4c906e 881 char pbuf[50]; // local print buffer
nixnax 120:bef89e4c906e 882 fillbuf();
nixnax 120:bef89e4c906e 883 sprintf(pbuf, "TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 120:bef89e4c906e 884 fillbuf();
nixnax 125:ea88200b1df6 885 putsWhileCheckingInput( pbuf );
nixnax 29:30de79d658f6 886 }
nixnax 29:30de79d658f6 887 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 888 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 889 putsWhileCheckingInput( ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP ); // print the tcp payload data
nixnax 125:ea88200b1df6 890 putsWhileCheckingInput("\n");
nixnax 29:30de79d658f6 891 }
nixnax 29:30de79d658f6 892 }
nixnax 26:11f4eb2663a7 893
nixnax 29:30de79d658f6 894 void TCPpacket()
nixnax 124:18ef53f1d8b7 895 {
nixnax 114:8a5d70bbc1b2 896 dumpHeaderIP(0); // dump incoming packet header
nixnax 114:8a5d70bbc1b2 897 dumpHeaderTCP(0); // dump incoming packet header
nixnax 77:abf92baebb42 898 if (v2) {
nixnax 77:abf92baebb42 899 dumpDataTCP();
nixnax 124:18ef53f1d8b7 900 }
nixnax 26:11f4eb2663a7 901 tcpHandler();
nixnax 11:f58998c24f0b 902 }
nixnax 11:f58998c24f0b 903
nixnax 29:30de79d658f6 904 void otherProtocol()
nixnax 29:30de79d658f6 905 {
nixnax 119:e14dd2bf0ea3 906 debugPrintf("Other IP protocol");
nixnax 29:30de79d658f6 907 }
nixnax 26:11f4eb2663a7 908
nixnax 29:30de79d658f6 909 void IPframe()
nixnax 29:30de79d658f6 910 {
nixnax 10:74f8233f72c0 911 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 912 switch (protocol) {
nixnax 29:30de79d658f6 913 case 1:
nixnax 29:30de79d658f6 914 ICMPpacket();
nixnax 29:30de79d658f6 915 break;
nixnax 29:30de79d658f6 916 case 2:
nixnax 29:30de79d658f6 917 IGMPpacket();
nixnax 29:30de79d658f6 918 break;
nixnax 29:30de79d658f6 919 case 17:
nixnax 29:30de79d658f6 920 UDPpacket();
nixnax 29:30de79d658f6 921 break;
nixnax 29:30de79d658f6 922 case 6:
nixnax 29:30de79d658f6 923 TCPpacket();
nixnax 29:30de79d658f6 924 break;
nixnax 29:30de79d658f6 925 default:
nixnax 29:30de79d658f6 926 otherProtocol();
nixnax 29:30de79d658f6 927 }
nixnax 29:30de79d658f6 928 }
nixnax 9:0992486d4a30 929
nixnax 29:30de79d658f6 930 void LCPconfReq()
nixnax 29:30de79d658f6 931 {
nixnax 119:e14dd2bf0ea3 932 debugPrintf("LCP Config ");
nixnax 9:0992486d4a30 933 if (ppp.pkt.buf[7] != 4) {
nixnax 111:6a3b77c065c0 934 ppp.pkt.buf[4]=4; // allow only "no options" which means Maximum Receive Unit (MRU) is default 1500 bytes
nixnax 119:e14dd2bf0ea3 935 debugPrintf("Reject\n");
nixnax 93:9675adc36882 936 send_pppFrame();
nixnax 9:0992486d4a30 937 } else {
nixnax 9:0992486d4a30 938 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 119:e14dd2bf0ea3 939 debugPrintf("Ack\n");
nixnax 93:9675adc36882 940 send_pppFrame();
nixnax 119:e14dd2bf0ea3 941 debugPrintf("LCP Ask\n");
nixnax 11:f58998c24f0b 942 ppp.pkt.buf[4]=1; // request no options
nixnax 93:9675adc36882 943 send_pppFrame();
nixnax 9:0992486d4a30 944 }
nixnax 9:0992486d4a30 945 }
nixnax 9:0992486d4a30 946
nixnax 29:30de79d658f6 947 void LCPconfAck()
nixnax 29:30de79d658f6 948 {
nixnax 119:e14dd2bf0ea3 949 debugPrintf("LCP Ack\n");
nixnax 29:30de79d658f6 950 }
nixnax 9:0992486d4a30 951
nixnax 29:30de79d658f6 952 void LCPend()
nixnax 29:30de79d658f6 953 {
nixnax 29:30de79d658f6 954 ppp.pkt.buf[4]=6;
nixnax 93:9675adc36882 955 send_pppFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 956 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 957 pppInitStruct(); // flush the receive buffer
nixnax 119:e14dd2bf0ea3 958 debugPrintf("LCP End\n");
nixnax 9:0992486d4a30 959 }
nixnax 9:0992486d4a30 960
nixnax 29:30de79d658f6 961 void LCPother()
nixnax 29:30de79d658f6 962 {
nixnax 119:e14dd2bf0ea3 963 debugPrintf("LCP Other\n");
nixnax 95:40af49390daf 964 dumpPPPFrame();
nixnax 29:30de79d658f6 965 }
nixnax 29:30de79d658f6 966
nixnax 29:30de79d658f6 967 void LCPframe()
nixnax 29:30de79d658f6 968 {
nixnax 29:30de79d658f6 969 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 970 switch (code) {
nixnax 29:30de79d658f6 971 case 1:
nixnax 29:30de79d658f6 972 LCPconfReq();
nixnax 29:30de79d658f6 973 break; // config request
nixnax 29:30de79d658f6 974 case 2:
nixnax 29:30de79d658f6 975 LCPconfAck();
nixnax 29:30de79d658f6 976 break; // config ack
nixnax 29:30de79d658f6 977 case 5:
nixnax 29:30de79d658f6 978 LCPend();
nixnax 29:30de79d658f6 979 break; // end connection
nixnax 29:30de79d658f6 980 default:
nixnax 29:30de79d658f6 981 LCPother();
nixnax 29:30de79d658f6 982 }
nixnax 9:0992486d4a30 983 }
nixnax 9:0992486d4a30 984
nixnax 29:30de79d658f6 985 void discardedFrame()
nixnax 29:30de79d658f6 986 {
nixnax 29:30de79d658f6 987 if (v0) {
nixnax 119:e14dd2bf0ea3 988 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 989 }
nixnax 9:0992486d4a30 990 }
nixnax 9:0992486d4a30 991
nixnax 29:30de79d658f6 992 void determinePacketType()
nixnax 29:30de79d658f6 993 {
nixnax 29:30de79d658f6 994 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 119:e14dd2bf0ea3 995 debugPrintf("byte0 != ff\n");
nixnax 29:30de79d658f6 996 return;
nixnax 29:30de79d658f6 997 }
nixnax 29:30de79d658f6 998 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 119:e14dd2bf0ea3 999 debugPrintf("byte1 != 3\n");
nixnax 29:30de79d658f6 1000 return;
nixnax 29:30de79d658f6 1001 }
nixnax 29:30de79d658f6 1002 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 119:e14dd2bf0ea3 1003 debugPrintf("byte2 != 21\n");
nixnax 29:30de79d658f6 1004 return;
nixnax 29:30de79d658f6 1005 }
nixnax 9:0992486d4a30 1006 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 1007 switch (packetType) {
nixnax 29:30de79d658f6 1008 case 0xc0:
nixnax 29:30de79d658f6 1009 LCPframe();
nixnax 29:30de79d658f6 1010 break; // link control
nixnax 29:30de79d658f6 1011 case 0x80:
nixnax 29:30de79d658f6 1012 IPCPframe();
nixnax 29:30de79d658f6 1013 break; // IP control
nixnax 29:30de79d658f6 1014 case 0x00:
nixnax 29:30de79d658f6 1015 IPframe();
nixnax 29:30de79d658f6 1016 break; // IP itself
nixnax 29:30de79d658f6 1017 default:
nixnax 29:30de79d658f6 1018 discardedFrame();
nixnax 9:0992486d4a30 1019 }
nixnax 29:30de79d658f6 1020 }
nixnax 9:0992486d4a30 1021
nixnax 119:e14dd2bf0ea3 1022 void wait_for_PPP_frame()
nixnax 50:ad4e7c3c88e5 1023 {
nixnax 85:53e57ff1cf05 1024 while(1) {
nixnax 93:9675adc36882 1025 fillbuf(); // handle received characters
nixnax 124:18ef53f1d8b7 1026 if ( ppp.rx.head != ppp.rx.tail ) {
nixnax 81:9ede60e9a2c8 1027 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 1028 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 1029 if (rx==FRAME_7E) {
nixnax 120:bef89e4c906e 1030 if (ppp.firstFrame) { // is this the start of the first frame start
nixnax 119:e14dd2bf0ea3 1031 ppp.firstFrame=0;
nixnax 120:bef89e4c906e 1032 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with virtual tail
nixnax 120:bef89e4c906e 1033 ppp.hdlc.frameStartIndex = ppp.rx.tail; // remember where first frame started
nixnax 119:e14dd2bf0ea3 1034 } else {
nixnax 119:e14dd2bf0ea3 1035 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 119:e14dd2bf0ea3 1036 processPPPFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 120:bef89e4c906e 1037 ppp.rx.rtail = ppp.rx.tail; // update real-time tail with virtual tail
nixnax 119:e14dd2bf0ea3 1038 ppp.hdlc.frameStartIndex = ppp.rx.tail; // where next frame will start
nixnax 119:e14dd2bf0ea3 1039 break;
nixnax 119:e14dd2bf0ea3 1040 }
nixnax 50:ad4e7c3c88e5 1041 }
nixnax 50:ad4e7c3c88e5 1042 }
nixnax 85:53e57ff1cf05 1043 }
nixnax 50:ad4e7c3c88e5 1044 }
nixnax 50:ad4e7c3c88e5 1045
nixnax 29:30de79d658f6 1046 void scanForConnectString()
nixnax 29:30de79d658f6 1047 {
nixnax 81:9ede60e9a2c8 1048 while(ppp.online == 0) {
nixnax 114:8a5d70bbc1b2 1049 fillbuf(); // gather received characters
nixnax 81:9ede60e9a2c8 1050 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 106:d14e6b597ca3 1051 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
nixnax 107:5fe806713d49 1052 if (found1 != NULL) {
nixnax 107:5fe806713d49 1053 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 119:e14dd2bf0ea3 1054 if (v0) debugPrintf("Found connect string \"CLIENT\", sent \"CLIENTSERVER\"\n");
nixnax 107:5fe806713d49 1055 pc.puts("CLIENTSERVER");
nixnax 120:bef89e4c906e 1056 ppp.online=1; // we are connected - set flag so we stop looking for the connect string
nixnax 119:e14dd2bf0ea3 1057 fillbuf();
nixnax 9:0992486d4a30 1058 }
nixnax 9:0992486d4a30 1059 }
nixnax 103:4f5512dd11cf 1060 }
nixnax 81:9ede60e9a2c8 1061
nixnax 0:2cf4880c312a 1062 int main()
nixnax 0:2cf4880c312a 1063 {
nixnax 120:bef89e4c906e 1064 pc.baud(115200); // USB serial port
nixnax 120:bef89e4c906e 1065 debugBaudRate(115200); // baud rate for our debug port - if we have one
nixnax 120:bef89e4c906e 1066 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 1067 pppInitStruct(); // initialize all the PPP properties
nixnax 0:2cf4880c312a 1068 while(1) {
nixnax 120:bef89e4c906e 1069 scanForConnectString(); // wait for connect
nixnax 81:9ede60e9a2c8 1070 while(ppp.online) {
nixnax 120:bef89e4c906e 1071 wait_for_PPP_frame(); // wait for a PPP frame
nixnax 81:9ede60e9a2c8 1072 }
nixnax 7:ab147f5e97ac 1073 }
nixnax 105:45001195b325 1074 }