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@66:f005b9fdf4d1, 2017-06-05 (annotated)

Committer:
nixnax
Date:
Mon Jun 05 15:34:53 2017 +0000
Revision:
66:f005b9fdf4d1
Parent:
65:23b17c43aa0f
Child:
67:a63e3486bcda
Separated HTML; Comments

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 0:2cf4880c312a 1 #include "mbed.h"
nixnax 0:2cf4880c312a 2
nixnax 29:30de79d658f6 3 // Copyright 2016 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 12:db0dc91f0231 4
nixnax 41:e58a5a09f411 5 // PPP-Blinky - "My Internet Of Thing"
nixnax 41:e58a5a09f411 6 // A Tiny Webserver Using Windows XP/7/8/10 Networking Over A Serial Port.
nixnax 0:2cf4880c312a 7
nixnax 41:e58a5a09f411 8 // Also receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 4:a469050d5b80 9
nixnax 41:e58a5a09f411 10 // Notes and Instructions
nixnax 41:e58a5a09f411 11 // http://bit.ly/PPP-Blinky-Instructions
nixnax 0:2cf4880c312a 12
nixnax 41:e58a5a09f411 13 // Handy reading material
nixnax 6:fba4c2e817b8 14 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 15 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 39:b90183d35f1e 16 // http://bit.ly/dialup777error - how to solve Dial Up Error 777 in Windows 7/8/10
nixnax 41:e58a5a09f411 17 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 18
nixnax 29:30de79d658f6 19 // Handy tools
nixnax 44:d0c61ae49ea5 20 // https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax 44:d0c61ae49ea5 21 // Wireshark - can't monitor Dial-Up network packets on windows, but useful - can import our dumpFrame routine's hex output
nixnax 29:30de79d658f6 22 // Microsoft network monitor - real-time monitoring of all our packets
nixnax 29:30de79d658f6 23 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 29:30de79d658f6 24 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE)
nixnax 41:e58a5a09f411 25 // The curl.exe program in Windows Powershell - use it like this to stress test the webserver: while (1) { curl 172.10.10.1 }
nixnax 29:30de79d658f6 26 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 41:e58a5a09f411 27 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 41:e58a5a09f411 28
nixnax 66:f005b9fdf4d1 29
nixnax 66:f005b9fdf4d1 30 // The #define below enables/disables a SECOND (optional) serial port that prints out interesting diagnostic messages.
nixnax 66:f005b9fdf4d1 31 // 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 48:6352c1411c5f 32 #define SERIAL_PORT_MONITOR_NO /* or SERIAL_PORT_MONITOR_YES */
nixnax 0:2cf4880c312a 33
nixnax 41:e58a5a09f411 34 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 66:f005b9fdf4d1 35 Serial xx(PC_10, PC_11); // Not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax 42:4de44be70bfd 36 #define debug(x...) xx.printf (x)
nixnax 41:e58a5a09f411 37 #else
nixnax 42:4de44be70bfd 38 #define debug(x...) {}
nixnax 41:e58a5a09f411 39 #endif
nixnax 41:e58a5a09f411 40
nixnax 66:f005b9fdf4d1 41 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 66:f005b9fdf4d1 42 #define v0 1
nixnax 66:f005b9fdf4d1 43 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 66:f005b9fdf4d1 44 #define v1 1
nixnax 29:30de79d658f6 45
nixnax 66:f005b9fdf4d1 46 // this is the webpage we serve when we get an HTTP request
nixnax 66:f005b9fdf4d1 47 // keep size under 900 bytes to fit in a single frame
nixnax 66:f005b9fdf4d1 48 const static char ourWebPage[] = "\
nixnax 66:f005b9fdf4d1 49 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 50 <html>\
nixnax 66:f005b9fdf4d1 51 <head>\
nixnax 66:f005b9fdf4d1 52 <title>mbed-PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 53 <script>\
nixnax 66:f005b9fdf4d1 54 window.onload=function(){\
nixnax 66:f005b9fdf4d1 55 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 66:f005b9fdf4d1 56 x().textContent = parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 57 </script>\
nixnax 66:f005b9fdf4d1 58 </head>\
nixnax 66:f005b9fdf4d1 59 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 60 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 61 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 62 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 63 </body>\
nixnax 66:f005b9fdf4d1 64 </html>"; // current size is approximately 500 characters
nixnax 66:f005b9fdf4d1 65
nixnax 66:f005b9fdf4d1 66 // The serial port on your mbed hardware. Your PC should view this as a standard dial-up networking modem. See instructions at the top.
nixnax 66:f005b9fdf4d1 67 // On a typical mbed hardware platform this is a USB virtual com port (VCP)
nixnax 66:f005b9fdf4d1 68 Serial pc(USBTX, USBRX); // usb virtual com port
nixnax 29:30de79d658f6 69
nixnax 29:30de79d658f6 70 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 71
nixnax 66:f005b9fdf4d1 72 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 73 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 74
nixnax 29:30de79d658f6 75 // the serial port receive buffer and packet buffer
nixnax 29:30de79d658f6 76 #define BUFLEN (1<<12)
nixnax 66:f005b9fdf4d1 77 char rxbufppp[BUFLEN]; // BUFLEN MUST be a power of two because we use & operator for fast wrap-around in rxHandler
nixnax 66:f005b9fdf4d1 78 char hdlcBuffer[2000]; // send and receive buffer for unstuffed (decoded) hdlc frames
nixnax 0:2cf4880c312a 79
nixnax 29:30de79d658f6 80 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 81 struct pppType {
nixnax 38:ab582987926e 82 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 83 int ident; // our IP ident value
nixnax 38:ab582987926e 84 unsigned int seq; // our TCP sequence number
nixnax 38:ab582987926e 85 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 86 int ledState; // state of LED1
nixnax 4:a469050d5b80 87 struct {
nixnax 20:5db9b77b38a6 88 char * buf;
nixnax 29:30de79d658f6 89 volatile int head;
nixnax 29:30de79d658f6 90 volatile int tail;
nixnax 38:ab582987926e 91 } rx; // serial port objects
nixnax 4:a469050d5b80 92 struct {
nixnax 38:ab582987926e 93 int len; // number of bytes in buffer
nixnax 38:ab582987926e 94 int crc; // PPP CRC (frame check)
nixnax 38:ab582987926e 95 char * buf; // the actual buffer
nixnax 38:ab582987926e 96 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 97 struct {
nixnax 50:ad4e7c3c88e5 98 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 99 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 100 int frameBusy; // busy capturing a frame
nixnax 50:ad4e7c3c88e5 101 } hdlc; // hdlc frame objects
nixnax 29:30de79d658f6 102 };
nixnax 31:e000c1b9c565 103
nixnax 29:30de79d658f6 104 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 105
nixnax 60:2b770949c911 106 // Initialize our globals
nixnax 29:30de79d658f6 107 void pppInitStruct()
nixnax 29:30de79d658f6 108 {
nixnax 29:30de79d658f6 109 ppp.online=0;
nixnax 49:2213f9c132b2 110 ppp.rx.buf=rxbufppp;
nixnax 29:30de79d658f6 111 ppp.rx.tail=0;
nixnax 29:30de79d658f6 112 ppp.rx.head=0;
nixnax 52:accc3026b2b0 113 ppp.pkt.buf=hdlcBuffer;
nixnax 29:30de79d658f6 114 ppp.pkt.len=0;
nixnax 29:30de79d658f6 115 ppp.ident=0;
nixnax 35:e7068df4d971 116 ppp.seq=1000;
nixnax 29:30de79d658f6 117 ppp.ledState=0;
nixnax 50:ad4e7c3c88e5 118 ppp.hdlc.frameBusy=0;
nixnax 29:30de79d658f6 119 }
nixnax 26:11f4eb2663a7 120
nixnax 43:aa57db08995d 121 void led1Toggle()
nixnax 43:aa57db08995d 122 {
nixnax 43:aa57db08995d 123 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 124 led1 = ppp.ledState;
nixnax 43:aa57db08995d 125 }
nixnax 43:aa57db08995d 126
nixnax 29:30de79d658f6 127 void crcReset()
nixnax 29:30de79d658f6 128 {
nixnax 29:30de79d658f6 129 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 130 }
nixnax 4:a469050d5b80 131
nixnax 29:30de79d658f6 132 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 133 {
nixnax 29:30de79d658f6 134 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 135 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 136 x>>=1;
nixnax 29:30de79d658f6 137 }
nixnax 29:30de79d658f6 138 }
nixnax 29:30de79d658f6 139
nixnax 29:30de79d658f6 140 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 141 {
nixnax 31:e000c1b9c565 142 crcReset();
nixnax 31:e000c1b9c565 143 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 144 return ppp.crc;
nixnax 29:30de79d658f6 145 }
nixnax 0:2cf4880c312a 146
nixnax 0:2cf4880c312a 147 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 148 {
nixnax 17:4918c893d802 149 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 150 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 151 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 152 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 153 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 154 }
nixnax 0:2cf4880c312a 155 }
nixnax 0:2cf4880c312a 156
nixnax 22:00df34cd4d7e 157 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 158 {
nixnax 22:00df34cd4d7e 159 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 160 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 161 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 162 return emptyStatus;
nixnax 0:2cf4880c312a 163 }
nixnax 0:2cf4880c312a 164
nixnax 0:2cf4880c312a 165 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 166 {
nixnax 63:9253b0e1b7d8 167 __disable_irq(); // critical section start
nixnax 63:9253b0e1b7d8 168 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 63:9253b0e1b7d8 169 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 63:9253b0e1b7d8 170 __enable_irq(); // critical section end
nixnax 63:9253b0e1b7d8 171 return x;
nixnax 0:2cf4880c312a 172 }
nixnax 0:2cf4880c312a 173
nixnax 50:ad4e7c3c88e5 174 void processHDLCFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 175 {
nixnax 38:ab582987926e 176 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 177 if(start==end) {
nixnax 29:30de79d658f6 178 pc.putc(0x7e);
nixnax 29:30de79d658f6 179 return;
nixnax 29:30de79d658f6 180 }
nixnax 9:0992486d4a30 181 crcReset();
nixnax 9:0992486d4a30 182 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 183 ppp.pkt.len=0;
nixnax 9:0992486d4a30 184 int unstuff=0;
nixnax 17:4918c893d802 185 int idx = start;
nixnax 17:4918c893d802 186 while(1) {
nixnax 9:0992486d4a30 187 if (unstuff==0) {
nixnax 49:2213f9c132b2 188 if (rxbufppp[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 189 else {
nixnax 49:2213f9c132b2 190 *dest = rxbufppp[idx];
nixnax 29:30de79d658f6 191 ppp.pkt.len++;
nixnax 29:30de79d658f6 192 dest++;
nixnax 49:2213f9c132b2 193 crcDo(rxbufppp[idx]);
nixnax 29:30de79d658f6 194 }
nixnax 66:f005b9fdf4d1 195 } else { // unstuff characters prefixed with 0x7d
nixnax 49:2213f9c132b2 196 *dest = rxbufppp[idx]^0x20;
nixnax 29:30de79d658f6 197 ppp.pkt.len++;
nixnax 29:30de79d658f6 198 dest++;
nixnax 49:2213f9c132b2 199 crcDo(rxbufppp[idx]^0x20);
nixnax 9:0992486d4a30 200 unstuff=0;
nixnax 9:0992486d4a30 201 }
nixnax 17:4918c893d802 202 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 203 if (idx == end) break;
nixnax 9:0992486d4a30 204 }
nixnax 29:30de79d658f6 205 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 206 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 207 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 208 determinePacketType();
nixnax 29:30de79d658f6 209 } else if (v0) {
nixnax 66:f005b9fdf4d1 210 debug("PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len); // ignore packets with CRC errors but print a debug line
nixnax 9:0992486d4a30 211 }
nixnax 9:0992486d4a30 212 }
nixnax 9:0992486d4a30 213
nixnax 38:ab582987926e 214 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 215 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 216 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 217 void dumpFrame()
nixnax 29:30de79d658f6 218 {
nixnax 42:4de44be70bfd 219 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 220 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 221 }
nixnax 16:cb0b80c24ba2 222
nixnax 29:30de79d658f6 223 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 224 {
nixnax 29:30de79d658f6 225 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 226 pc.putc(0x7d);
nixnax 66:f005b9fdf4d1 227 pc.putc(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 228 } else {
nixnax 29:30de79d658f6 229 pc.putc(ch);
nixnax 29:30de79d658f6 230 }
nixnax 11:f58998c24f0b 231 }
nixnax 9:0992486d4a30 232
nixnax 66:f005b9fdf4d1 233 void sendFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 234 {
nixnax 17:4918c893d802 235 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 236 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 237 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 238 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 239 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 240 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 241 }
nixnax 9:0992486d4a30 242
nixnax 66:f005b9fdf4d1 243 void ipConfigRequestHandler()
nixnax 29:30de79d658f6 244 {
nixnax 64:677b9713a120 245 debug("IPCP Conf ");
nixnax 9:0992486d4a30 246 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 66:f005b9fdf4d1 247 debug("Rej\n"); // reject any options that are requested
nixnax 9:0992486d4a30 248 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 249 sendFrame();
nixnax 9:0992486d4a30 250 } else {
nixnax 64:677b9713a120 251 debug("Ack\n");
nixnax 9:0992486d4a30 252 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 253 sendFrame(); // acknowledge
nixnax 64:677b9713a120 254 debug("IPCP Ask\n");
nixnax 9:0992486d4a30 255 // send our own request now
nixnax 12:db0dc91f0231 256 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 257 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 258 sendFrame(); // this is our request
nixnax 9:0992486d4a30 259 }
nixnax 9:0992486d4a30 260 }
nixnax 9:0992486d4a30 261
nixnax 29:30de79d658f6 262 void ipAckHandler()
nixnax 29:30de79d658f6 263 {
nixnax 64:677b9713a120 264 debug("IPCP Grant\n");
nixnax 29:30de79d658f6 265 }
nixnax 9:0992486d4a30 266
nixnax 29:30de79d658f6 267 void ipNackHandler()
nixnax 29:30de79d658f6 268 {
nixnax 64:677b9713a120 269 debug("IPCP Nack\n");
nixnax 29:30de79d658f6 270 }
nixnax 9:0992486d4a30 271
nixnax 29:30de79d658f6 272 void ipDefaultHandler()
nixnax 29:30de79d658f6 273 {
nixnax 64:677b9713a120 274 debug("IPCP Other\n");
nixnax 29:30de79d658f6 275 }
nixnax 29:30de79d658f6 276
nixnax 29:30de79d658f6 277 void IPCPframe()
nixnax 29:30de79d658f6 278 {
nixnax 9:0992486d4a30 279 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 280 switch (code) {
nixnax 29:30de79d658f6 281 case 1:
nixnax 66:f005b9fdf4d1 282 ipConfigRequestHandler();
nixnax 29:30de79d658f6 283 break;
nixnax 29:30de79d658f6 284 case 2:
nixnax 29:30de79d658f6 285 ipAckHandler();
nixnax 29:30de79d658f6 286 break;
nixnax 29:30de79d658f6 287 case 3:
nixnax 29:30de79d658f6 288 ipNackHandler();
nixnax 29:30de79d658f6 289 break;
nixnax 29:30de79d658f6 290 default:
nixnax 29:30de79d658f6 291 ipDefaultHandler();
nixnax 9:0992486d4a30 292 }
nixnax 29:30de79d658f6 293 }
nixnax 9:0992486d4a30 294
nixnax 29:30de79d658f6 295 void UDPpacket()
nixnax 29:30de79d658f6 296 {
nixnax 12:db0dc91f0231 297 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 298 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 299 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 63:9253b0e1b7d8 300 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 301 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 302 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 303 #endif
nixnax 12:db0dc91f0231 304 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 305 char * udpInf = udpBlock+8; // actual start of info
nixnax 63:9253b0e1b7d8 306 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 307 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 308 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 309 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 310 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 311 #endif
nixnax 29:30de79d658f6 312 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 313 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 42:4de44be70bfd 314 if(v1) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 42:4de44be70bfd 315 if(v1) debug("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort);
nixnax 42:4de44be70bfd 316 debug("Len %d ", udpLength);
nixnax 29:30de79d658f6 317 int printSize = udpLength;
nixnax 29:30de79d658f6 318 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 319 if (v0) {
nixnax 29:30de79d658f6 320 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 321 char ch = udpInf[i];
nixnax 29:30de79d658f6 322 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 323 debug("%c", ch);
nixnax 29:30de79d658f6 324 } else {
nixnax 64:677b9713a120 325 debug("_");
nixnax 29:30de79d658f6 326 }
nixnax 29:30de79d658f6 327 }
nixnax 64:677b9713a120 328 debug("\n");
nixnax 29:30de79d658f6 329 }
nixnax 12:db0dc91f0231 330 }
nixnax 11:f58998c24f0b 331
nixnax 29:30de79d658f6 332 int dataCheckSum(char * ptr, int len)
nixnax 29:30de79d658f6 333 {
nixnax 29:30de79d658f6 334 int sum=0;
nixnax 29:30de79d658f6 335 int placeHolder;
nixnax 29:30de79d658f6 336 if (len&1) {
nixnax 38:ab582987926e 337 placeHolder = ptr[len-1]; // when length is odd stuff in a zero byte
nixnax 29:30de79d658f6 338 ptr[len-1]=0;
nixnax 29:30de79d658f6 339 }
nixnax 29:30de79d658f6 340 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 341 int hi = *ptr;
nixnax 29:30de79d658f6 342 ptr++;
nixnax 29:30de79d658f6 343 int lo = *ptr;
nixnax 29:30de79d658f6 344 ptr++;
nixnax 11:f58998c24f0b 345 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 346 sum = sum + val;
nixnax 11:f58998c24f0b 347 }
nixnax 11:f58998c24f0b 348 sum = sum + (sum>>16);
nixnax 29:30de79d658f6 349 if (len&1) {
nixnax 29:30de79d658f6 350 ptr[len-1] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 351 }
nixnax 12:db0dc91f0231 352 return ~sum;
nixnax 29:30de79d658f6 353 }
nixnax 11:f58998c24f0b 354
nixnax 29:30de79d658f6 355 void headerCheckSum()
nixnax 29:30de79d658f6 356 {
nixnax 11:f58998c24f0b 357 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 358 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 359 int sum=0;
nixnax 11:f58998c24f0b 360
nixnax 29:30de79d658f6 361 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 362 int hi = *ptr;
nixnax 29:30de79d658f6 363 ptr++;
nixnax 29:30de79d658f6 364 int lo = *ptr;
nixnax 29:30de79d658f6 365 ptr++;
nixnax 11:f58998c24f0b 366 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 367 sum = sum + val;
nixnax 11:f58998c24f0b 368 }
nixnax 11:f58998c24f0b 369 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 370 sum = ~sum;
nixnax 11:f58998c24f0b 371 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 372 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 373 }
nixnax 9:0992486d4a30 374
nixnax 29:30de79d658f6 375 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 376 {
nixnax 12:db0dc91f0231 377 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 378 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 379 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 380 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 381 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 382 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 383 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 384 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 385 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 386 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 387 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 388 char * dstAdr = ipPkt+16;
nixnax 63:9253b0e1b7d8 389 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 390 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 391 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 63:9253b0e1b7d8 392 #endif
nixnax 42:4de44be70bfd 393 debug("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 42:4de44be70bfd 394 debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 395 char src[4];
nixnax 29:30de79d658f6 396 char dst[4];
nixnax 12:db0dc91f0231 397 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 398 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 399 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 400 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 401 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 402 chkSum[0]=0;
nixnax 29:30de79d658f6 403 chkSum[1]=0;
nixnax 12:db0dc91f0231 404 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 405 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 406 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 407 icmpSum[0]=0;
nixnax 29:30de79d658f6 408 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 409 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 16:cb0b80c24ba2 410 int sum = dataCheckSum( icmpType, icmpLength); // this checksum on icmp data portion
nixnax 29:30de79d658f6 411 icmpSum[0]=sum>>8;
nixnax 29:30de79d658f6 412 icmpSum[1]=sum; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 413
nixnax 16:cb0b80c24ba2 414 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 415 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 416 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 417 if (v0) {
nixnax 29:30de79d658f6 418 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 419 char ch = icmpData[i];
nixnax 29:30de79d658f6 420 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 421 debug("%c",ch);
nixnax 29:30de79d658f6 422 } else {
nixnax 64:677b9713a120 423 debug("_");
nixnax 29:30de79d658f6 424 }
nixnax 29:30de79d658f6 425 }
nixnax 64:677b9713a120 426 debug("\n");
nixnax 29:30de79d658f6 427 }
nixnax 15:b0154c910143 428 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 429
nixnax 12:db0dc91f0231 430 } else {
nixnax 29:30de79d658f6 431 if (v0) {
nixnax 42:4de44be70bfd 432 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 433 }
nixnax 11:f58998c24f0b 434 }
nixnax 11:f58998c24f0b 435 }
nixnax 11:f58998c24f0b 436
nixnax 29:30de79d658f6 437 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 438 {
nixnax 29:30de79d658f6 439 if (v0) {
nixnax 42:4de44be70bfd 440 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 441 }
nixnax 29:30de79d658f6 442 }
nixnax 11:f58998c24f0b 443
nixnax 29:30de79d658f6 444 void dumpHeaderIP ()
nixnax 29:30de79d658f6 445 {
nixnax 26:11f4eb2663a7 446 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 447 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 448 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 449 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 450 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 451 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 452 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 453 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 454 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 455 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 456 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 457 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 458 #endif
nixnax 26:11f4eb2663a7 459 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 460 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 461
nixnax 55:43faae812be3 462 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 463 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 464 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 465 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 466 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 467 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 468 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 469 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 470 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 471 int protocolIP = protocol[0];
nixnax 63:9253b0e1b7d8 472 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 473 #endif
nixnax 55:43faae812be3 474
nixnax 29:30de79d658f6 475 char srcIP [16];
nixnax 29:30de79d658f6 476 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 477 char dstIP [16];
nixnax 29:30de79d658f6 478 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 42:4de44be70bfd 479 if (v0) debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 42:4de44be70bfd 480 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 481 }
nixnax 26:11f4eb2663a7 482
nixnax 29:30de79d658f6 483 void dumpHeaderTCP()
nixnax 29:30de79d658f6 484 {
nixnax 29:30de79d658f6 485 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 486 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 63:9253b0e1b7d8 487 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 488 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 489 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 63:9253b0e1b7d8 490 #endif
nixnax 29:30de79d658f6 491 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 63:9253b0e1b7d8 492 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 31:e000c1b9c565 493 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 494 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 63:9253b0e1b7d8 495 #endif
nixnax 26:11f4eb2663a7 496 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 497
nixnax 66:f005b9fdf4d1 498 char flagInfo[10]; // text string presentating the TCP flags
nixnax 66:f005b9fdf4d1 499 memset(flagInfo,'.', 9); // fill string with "........."
nixnax 66:f005b9fdf4d1 500 memset(flagInfo,0,1); // null terminate string
nixnax 66:f005b9fdf4d1 501
nixnax 29:30de79d658f6 502 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 503 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 504 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 505 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 506 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 507 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 508 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 509 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 510 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 29:30de79d658f6 511 if (v0) {
nixnax 66:f005b9fdf4d1 512 debug("Flags %s Seq %u Ack %u", flagInfo, seq, ack); // show the flags in debug
nixnax 29:30de79d658f6 513 }
nixnax 29:30de79d658f6 514 }
nixnax 29:30de79d658f6 515
nixnax 29:30de79d658f6 516 void tcpHandler()
nixnax 29:30de79d658f6 517 {
nixnax 26:11f4eb2663a7 518 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 519 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 520 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 521 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 522 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 523 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 524 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 525 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 526 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 527 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 528
nixnax 29:30de79d658f6 529 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 530 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 531
nixnax 29:30de79d658f6 532 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 533 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 534 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 535 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 536 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 537 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 538 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 539 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 540
nixnax 26:11f4eb2663a7 541 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 542 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 543 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 544
nixnax 31:e000c1b9c565 545 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 546 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 29:30de79d658f6 547
nixnax 35:e7068df4d971 548 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 549
nixnax 35:e7068df4d971 550 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 35:e7068df4d971 551 int incomingLen = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 28:1aa629be05e7 552
nixnax 29:30de79d658f6 553 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 554 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 555 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 556 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 557 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 558
nixnax 38:ab582987926e 559 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 38:ab582987926e 560 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 38:ab582987926e 561 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 29:30de79d658f6 562
nixnax 35:e7068df4d971 563 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 564 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 565 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 566
nixnax 61:b3c1a04efd0a 567 ppp.seq = ack; // always adopt their sequence number calculation in place of doing our own calculation
nixnax 35:e7068df4d971 568
nixnax 66:f005b9fdf4d1 569 // if ( ((flagsTCP & ~TCP_FLAG_ACK) == 0) && ((flagsTCP & TCP_FLAG_ACK) != 0) ) {
nixnax 66:f005b9fdf4d1 570 if ( flagsTCP == TCP_FLAG_ACK ) {
nixnax 38:ab582987926e 571 if (incomingLen == 0) { // ignore - just an empty ack packet
nixnax 38:ab582987926e 572 return;
nixnax 38:ab582987926e 573 }
nixnax 38:ab582987926e 574 } else if ( (flagsTCP & TCP_FLAG_SYN) != 0 ) { // got SYN flag
nixnax 36:2a9b457f8276 575 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // do a syn-ack
nixnax 38:ab582987926e 576 seq++; // for SYN flag we have to increase sequence by 1
nixnax 38:ab582987926e 577 } else if ( (flagsTCP & TCP_FLAG_FIN) != 0 ) { // got FIN flag
nixnax 38:ab582987926e 578 seq++; // for FIN flag we have to increase sequence by 1
nixnax 38:ab582987926e 579 } else if ( (flagsTCP & TCP_FLAG_PSH) != 0 ) { // got PSH flag (push)
nixnax 38:ab582987926e 580 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 38:ab582987926e 581 fastResponse = 1; // we can respond fast to a push
nixnax 38:ab582987926e 582 // It's a push, so let's check the incoming data for an HTTP GET request
nixnax 31:e000c1b9c565 583 if ( strncmp(dataStart, "GET / HTTP/1.1", 14) == 0) {
nixnax 66:f005b9fdf4d1 584 dataLen = 1024; // this buffer has to hold the web page and the content below, so keep total size under 1024 or increase this
nixnax 38:ab582987926e 585 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 50:ad4e7c3c88e5 586
nixnax 38:ab582987926e 587 int n=0; // number of bytes we have printed so far
nixnax 31:e000c1b9c565 588 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 44:d0c61ae49ea5 589 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 44:d0c61ae49ea5 590 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 44:d0c61ae49ea5 591 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 44:d0c61ae49ea5 592 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 66:f005b9fdf4d1 593 int nHeader=n; // byte size of the HTTP header. Note - seems like this must be 1+(multiple of four)
nixnax 44:d0c61ae49ea5 594
nixnax 66:f005b9fdf4d1 595 // this is where we insert our web page into the buffer
nixnax 66:f005b9fdf4d1 596 n=n+sprintf(n+dataStart,"%s\r\n", ourWebPage);
nixnax 50:ad4e7c3c88e5 597
nixnax 66:f005b9fdf4d1 598 int contentLength = n-nHeader; // contentLength is the count of every character after the header
nixnax 44:d0c61ae49ea5 599 int cSize = 5; // maximum number of digits we allow for Content-Length
nixnax 44:d0c61ae49ea5 600 char contentLengthString[cSize+1]; // temporary buffer to create Content-Length string
nixnax 66:f005b9fdf4d1 601 snprintf(contentLengthString,cSize+1,"%*d",cSize,contentLength); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 66:f005b9fdf4d1 602 memcpy(dataStart+contentLengthStart, contentLengthString, cSize); // copy Content-Length to it's place in the send buffer
nixnax 50:ad4e7c3c88e5 603
nixnax 31:e000c1b9c565 604 if (v0) {
nixnax 44:d0c61ae49ea5 605 debug("HTTP GET BufferSize %d*32=%d Header %d Content-Length %d Total %d Available %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n);
nixnax 31:e000c1b9c565 606 }
nixnax 44:d0c61ae49ea5 607 dataLen=n; // update the buffer size
nixnax 38:ab582987926e 608 } else if ( strncmp(dataStart, "GET /", 4) == 0) { // all other HTTP GET requests get 404 Not Found response
nixnax 44:d0c61ae49ea5 609 dataLen = 32*32; // maximum size for File not found webpage
nixnax 38:ab582987926e 610 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 50:ad4e7c3c88e5 611
nixnax 38:ab582987926e 612 int n=0; // number of bytes we have printed so far
nixnax 41:e58a5a09f411 613 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 44:d0c61ae49ea5 614 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 44:d0c61ae49ea5 615 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 44:d0c61ae49ea5 616 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 47:00a5ca075f8f 617 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 47:00a5ca075f8f 618 int nHeader=n; // byte total of all headers. Note - seems like this must be 1+(multiple of four)
nixnax 44:d0c61ae49ea5 619
nixnax 44:d0c61ae49ea5 620 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head></head>"); // html start
nixnax 44:d0c61ae49ea5 621 n=n+sprintf(n+dataStart,"<body><h1>File Not Found</h1></body>");
nixnax 47:00a5ca075f8f 622 n=n+sprintf(n+dataStart,"</html>\r\n"); // html end
nixnax 44:d0c61ae49ea5 623
nixnax 44:d0c61ae49ea5 624 int contentLength = n-nHeader; // Content-Length is the count of every character after the header
nixnax 44:d0c61ae49ea5 625 int cSize = 5; // maximum number of digits we allow for Content-Length
nixnax 44:d0c61ae49ea5 626 char contentLengthString[cSize+1]; // temporary buffer to create Content-Length string
nixnax 44:d0c61ae49ea5 627 snprintf(contentLengthString,cSize+1,"%*d",cSize,contentLength); // print Content-Length with leading spaces and fixed width = csize
nixnax 44:d0c61ae49ea5 628 memcpy(dataStart+contentLengthStart, contentLengthString, cSize); // copy Content-Length to the send buffer
nixnax 44:d0c61ae49ea5 629
nixnax 31:e000c1b9c565 630 if (v0) {
nixnax 44:d0c61ae49ea5 631 debug("HTTP GET BufSize %d*32=%d Header %d Content-Length %d Total %d Available %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n);
nixnax 31:e000c1b9c565 632 }
nixnax 44:d0c61ae49ea5 633 dataLen=n; // update the buffer size
nixnax 35:e7068df4d971 634 } else {
nixnax 38:ab582987926e 635 dataLen=0; // we did not find a valid HTTP request, so just ACK with zero data
nixnax 29:30de79d658f6 636 }
nixnax 36:2a9b457f8276 637 } else {
nixnax 38:ab582987926e 638 dataLen=0; // it's not any TCP Flag Combo that needs special handling
nixnax 28:1aa629be05e7 639 }
nixnax 29:30de79d658f6 640
nixnax 38:ab582987926e 641 // All the TCP flag handling is now done
nixnax 29:30de79d658f6 642
nixnax 38:ab582987926e 643 // Now we have to recalculate all the header sizes, swap IP address/port source and destination, and do the IP and TCP checksums
nixnax 26:11f4eb2663a7 644
nixnax 65:23b17c43aa0f 645 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 646 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 647 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 648 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 649
nixnax 60:2b770949c911 650 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 651 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 652 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 29:30de79d658f6 653
nixnax 38:ab582987926e 654 ack = seq + incomingLen; // acknowledge the number of bytes that they sent by adding it to "our" sequence number
nixnax 38:ab582987926e 655 seq = ppp.seq; // set up the sequence number we have to respond with
nixnax 38:ab582987926e 656
nixnax 38:ab582987926e 657 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 658 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 659 acktcp[2]=ack>>8;
nixnax 38:ab582987926e 660 acktcp[3]=ack>>0; // save ack
nixnax 38:ab582987926e 661
nixnax 38:ab582987926e 662 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 663 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 664 seqtcp[2]=seq>>8;
nixnax 38:ab582987926e 665 seqtcp[3]=seq>>0; // save seq
nixnax 38:ab582987926e 666
nixnax 38:ab582987926e 667 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 668
nixnax 38:ab582987926e 669 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 670 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 671 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 672 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 673 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 674
nixnax 38:ab582987926e 675 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 676
nixnax 61:b3c1a04efd0a 677 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 678 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 679 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 680
nixnax 64:677b9713a120 681 // 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 682 // 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 683
nixnax 62:f192926e42f1 684 char * pseudoHeader = s-12; // mark the start of the TCP pseudo-header
nixnax 62:f192926e42f1 685 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes in the IP header where the TCP pseudo-Header must be built
nixnax 61:b3c1a04efd0a 686 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 687 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 688 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 689 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 690 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 691
nixnax 61:b3c1a04efd0a 692 // pseudo-header built, now we can calculate TCP checksum
nixnax 63:9253b0e1b7d8 693
nixnax 29:30de79d658f6 694 checksumtcp[0]=0;
nixnax 29:30de79d658f6 695 checksumtcp[1]=0;
nixnax 62:f192926e42f1 696 int pseudoHeaderSum=dataCheckSum(pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 697 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 698 checksumtcp[1]=pseudoHeaderSum;
nixnax 61:b3c1a04efd0a 699 memcpy( s-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 60:2b770949c911 700
nixnax 36:2a9b457f8276 701 if (fastResponse==1) {
nixnax 36:2a9b457f8276 702 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 703 } else {
nixnax 38:ab582987926e 704 wait(0.2); // normally, you wait 200 ms before sending a TCP packet
nixnax 36:2a9b457f8276 705 }
nixnax 38:ab582987926e 706 sendFrame(); // All done! Send the TCP packet
nixnax 38:ab582987926e 707 ppp.seq = ppp.seq + dataLen; // increase OUR sequence by the outgoing data length - for the next round
nixnax 29:30de79d658f6 708 }
nixnax 26:11f4eb2663a7 709
nixnax 29:30de79d658f6 710 void dumpDataTCP()
nixnax 29:30de79d658f6 711 {
nixnax 26:11f4eb2663a7 712 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 713 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 714 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 715 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 716 if (v1) {
nixnax 42:4de44be70bfd 717 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 718 }
nixnax 29:30de79d658f6 719 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 720 ppp.pkt.buf[4+ipHeaderLen+headerSizeTCP+dataLen]=0; // insert a null after the data so debug printf stops printing after the data
nixnax 42:4de44be70bfd 721 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 722 }
nixnax 29:30de79d658f6 723 }
nixnax 26:11f4eb2663a7 724
nixnax 29:30de79d658f6 725 void TCPpacket()
nixnax 29:30de79d658f6 726 {
nixnax 26:11f4eb2663a7 727 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 728 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 729 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 730 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 731 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 732 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 733 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 734 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 735 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 736 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 737 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 738 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 739 #endif
nixnax 26:11f4eb2663a7 740 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 741 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 742
nixnax 55:43faae812be3 743 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 744 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 745 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 746 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 747 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 748 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 749 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 750 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 751 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 752 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 753 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 754 #endif
nixnax 29:30de79d658f6 755 char srcIP [16];
nixnax 29:30de79d658f6 756 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 757 char dstIP [16];
nixnax 29:30de79d658f6 758 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 759 if (v0) {
nixnax 42:4de44be70bfd 760 debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 29:30de79d658f6 761 }
nixnax 29:30de79d658f6 762 if (v0) {
nixnax 42:4de44be70bfd 763 debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 764 }
nixnax 28:1aa629be05e7 765 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 766 dumpDataTCP();
nixnax 26:11f4eb2663a7 767 tcpHandler();
nixnax 11:f58998c24f0b 768 }
nixnax 11:f58998c24f0b 769
nixnax 29:30de79d658f6 770 void otherProtocol()
nixnax 29:30de79d658f6 771 {
nixnax 64:677b9713a120 772 debug("Other IP protocol");
nixnax 29:30de79d658f6 773 }
nixnax 26:11f4eb2663a7 774
nixnax 29:30de79d658f6 775 void IPframe()
nixnax 29:30de79d658f6 776 {
nixnax 10:74f8233f72c0 777 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 778 switch (protocol) {
nixnax 29:30de79d658f6 779 case 1:
nixnax 29:30de79d658f6 780 ICMPpacket();
nixnax 29:30de79d658f6 781 break;
nixnax 29:30de79d658f6 782 case 2:
nixnax 29:30de79d658f6 783 IGMPpacket();
nixnax 29:30de79d658f6 784 break;
nixnax 29:30de79d658f6 785 case 17:
nixnax 29:30de79d658f6 786 UDPpacket();
nixnax 29:30de79d658f6 787 break;
nixnax 29:30de79d658f6 788 case 6:
nixnax 29:30de79d658f6 789 TCPpacket();
nixnax 29:30de79d658f6 790 break;
nixnax 29:30de79d658f6 791 default:
nixnax 29:30de79d658f6 792 otherProtocol();
nixnax 29:30de79d658f6 793 }
nixnax 29:30de79d658f6 794 }
nixnax 9:0992486d4a30 795
nixnax 29:30de79d658f6 796 void LCPconfReq()
nixnax 29:30de79d658f6 797 {
nixnax 64:677b9713a120 798 debug("LCP Config ");
nixnax 9:0992486d4a30 799 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 800 ppp.pkt.buf[4]=4; // allow only no options
nixnax 64:677b9713a120 801 debug("Reject\n");
nixnax 29:30de79d658f6 802 sendFrame();
nixnax 9:0992486d4a30 803 } else {
nixnax 9:0992486d4a30 804 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 64:677b9713a120 805 debug("Ack\n");
nixnax 9:0992486d4a30 806 sendFrame();
nixnax 64:677b9713a120 807 debug("LCP Ask\n");
nixnax 11:f58998c24f0b 808 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 809 sendFrame();
nixnax 9:0992486d4a30 810 }
nixnax 9:0992486d4a30 811 }
nixnax 9:0992486d4a30 812
nixnax 29:30de79d658f6 813 void LCPconfAck()
nixnax 29:30de79d658f6 814 {
nixnax 64:677b9713a120 815 debug("LCP Ack\n");
nixnax 29:30de79d658f6 816 }
nixnax 9:0992486d4a30 817
nixnax 29:30de79d658f6 818 void LCPend()
nixnax 29:30de79d658f6 819 {
nixnax 64:677b9713a120 820 debug("LCP End\n");
nixnax 29:30de79d658f6 821 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 822 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 823 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 824 }
nixnax 9:0992486d4a30 825
nixnax 29:30de79d658f6 826 void LCPother()
nixnax 29:30de79d658f6 827 {
nixnax 64:677b9713a120 828 debug("LCP Other\n");
nixnax 29:30de79d658f6 829 dumpFrame();
nixnax 29:30de79d658f6 830 }
nixnax 29:30de79d658f6 831
nixnax 29:30de79d658f6 832 void LCPframe()
nixnax 29:30de79d658f6 833 {
nixnax 29:30de79d658f6 834 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 835 switch (code) {
nixnax 29:30de79d658f6 836 case 1:
nixnax 29:30de79d658f6 837 LCPconfReq();
nixnax 29:30de79d658f6 838 break; // config request
nixnax 29:30de79d658f6 839 case 2:
nixnax 29:30de79d658f6 840 LCPconfAck();
nixnax 29:30de79d658f6 841 break; // config ack
nixnax 29:30de79d658f6 842 case 5:
nixnax 29:30de79d658f6 843 LCPend();
nixnax 29:30de79d658f6 844 break; // end connection
nixnax 29:30de79d658f6 845 default:
nixnax 29:30de79d658f6 846 LCPother();
nixnax 29:30de79d658f6 847 }
nixnax 9:0992486d4a30 848 }
nixnax 9:0992486d4a30 849
nixnax 29:30de79d658f6 850 void discardedFrame()
nixnax 29:30de79d658f6 851 {
nixnax 29:30de79d658f6 852 if (v0) {
nixnax 42:4de44be70bfd 853 debug("Dropping frame %02x %02x %02x %02x\n", ppp.pkt.buf[0],ppp.pkt.buf[1],ppp.pkt.buf[2],ppp.pkt.buf[3]);
nixnax 29:30de79d658f6 854 }
nixnax 9:0992486d4a30 855 }
nixnax 9:0992486d4a30 856
nixnax 29:30de79d658f6 857 void determinePacketType()
nixnax 29:30de79d658f6 858 {
nixnax 29:30de79d658f6 859 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 64:677b9713a120 860 debug("byte0 != ff\n");
nixnax 29:30de79d658f6 861 return;
nixnax 29:30de79d658f6 862 }
nixnax 29:30de79d658f6 863 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 64:677b9713a120 864 debug("byte1 != 3\n");
nixnax 29:30de79d658f6 865 return;
nixnax 29:30de79d658f6 866 }
nixnax 29:30de79d658f6 867 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 64:677b9713a120 868 debug("byte2 != 21\n");
nixnax 29:30de79d658f6 869 return;
nixnax 29:30de79d658f6 870 }
nixnax 9:0992486d4a30 871 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 872 switch (packetType) {
nixnax 29:30de79d658f6 873 case 0xc0:
nixnax 29:30de79d658f6 874 LCPframe();
nixnax 29:30de79d658f6 875 break; // link control
nixnax 29:30de79d658f6 876 case 0x80:
nixnax 29:30de79d658f6 877 IPCPframe();
nixnax 29:30de79d658f6 878 break; // IP control
nixnax 29:30de79d658f6 879 case 0x00:
nixnax 29:30de79d658f6 880 IPframe();
nixnax 29:30de79d658f6 881 break; // IP itself
nixnax 29:30de79d658f6 882 default:
nixnax 29:30de79d658f6 883 discardedFrame();
nixnax 9:0992486d4a30 884 }
nixnax 29:30de79d658f6 885 }
nixnax 9:0992486d4a30 886
nixnax 50:ad4e7c3c88e5 887 void wait_for_HDLC_frame()
nixnax 50:ad4e7c3c88e5 888 {
nixnax 50:ad4e7c3c88e5 889 while ( rxbufNotEmpty() ) {
nixnax 50:ad4e7c3c88e5 890 int rx = pc_getBuf();
nixnax 50:ad4e7c3c88e5 891 if (ppp.hdlc.frameBusy) {
nixnax 50:ad4e7c3c88e5 892 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 893 ppp.hdlc.frameBusy=0; // done gathering frame
nixnax 50:ad4e7c3c88e5 894 if (ppp.rx.tail == 0) { // did we just wrap around?
nixnax 50:ad4e7c3c88e5 895 ppp.hdlc.frameEndIndex=BUFLEN-1; // wrap back to end of buffer
nixnax 51:a86d56844324 896 } else {
nixnax 50:ad4e7c3c88e5 897 ppp.hdlc.frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 50:ad4e7c3c88e5 898 }
nixnax 50:ad4e7c3c88e5 899 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex);
nixnax 50:ad4e7c3c88e5 900 }
nixnax 50:ad4e7c3c88e5 901 } else {
nixnax 50:ad4e7c3c88e5 902 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 903 ppp.hdlc.frameBusy=1; // start gathering frame
nixnax 50:ad4e7c3c88e5 904 ppp.hdlc.frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 50:ad4e7c3c88e5 905 }
nixnax 50:ad4e7c3c88e5 906 }
nixnax 50:ad4e7c3c88e5 907 }
nixnax 50:ad4e7c3c88e5 908 }
nixnax 50:ad4e7c3c88e5 909
nixnax 29:30de79d658f6 910 void scanForConnectString()
nixnax 29:30de79d658f6 911 {
nixnax 9:0992486d4a30 912 if ( ppp.online==0 ) {
nixnax 49:2213f9c132b2 913 char * clientFound = strstr( (char *)rxbufppp, "CLIENTCLIENT" ); // look for PC string
nixnax 29:30de79d658f6 914 if( clientFound ) {
nixnax 57:8deab70fef2e 915 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't find it again
nixnax 9:0992486d4a30 916 pc.printf("CLIENTSERVER"); // respond to PC
nixnax 9:0992486d4a30 917 ppp.online=1; // we can stop looking for the string
nixnax 64:677b9713a120 918 debug("Connect string found\n");
nixnax 9:0992486d4a30 919 }
nixnax 9:0992486d4a30 920 }
nixnax 9:0992486d4a30 921 }
nixnax 9:0992486d4a30 922
nixnax 0:2cf4880c312a 923 int main()
nixnax 0:2cf4880c312a 924 {
nixnax 14:c65831c25aaa 925 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 926 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 49:2213f9c132b2 927 xx.baud(115200); // second serial port for debug messages
nixnax 9:0992486d4a30 928 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 929 #endif
nixnax 9:0992486d4a30 930 pppInitStruct(); // initialize all the PPP properties
nixnax 9:0992486d4a30 931 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 0:2cf4880c312a 932 while(1) {
nixnax 51:a86d56844324 933 scanForConnectString(); // respond to connect command from windows dial up networking
nixnax 50:ad4e7c3c88e5 934 wait_for_HDLC_frame();
nixnax 7:ab147f5e97ac 935 }
nixnax 7:ab147f5e97ac 936 }