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@84:456e73151f11, 2017-07-18 (annotated)

Committer:
nixnax
Date:
Tue Jul 18 01:01:10 2017 +0000
Revision:
84:456e73151f11
Parent:
83:cdcb81d1910f
Child:
85:53e57ff1cf05
html changes

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 81:9ede60e9a2c8 1 // PPP-Blinky - "My Internet Of Thing"
nixnax 0:2cf4880c312a 2
nixnax 72:ad3d12753acf 3 // A Tiny Webserver Using Windows XP/7/8/10 Dial-Up Networking Over A Serial Port.
nixnax 0:2cf4880c312a 4
nixnax 41:e58a5a09f411 5 // Also receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 4:a469050d5b80 6
nixnax 81:9ede60e9a2c8 7 // 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 81:9ede60e9a2c8 8
nixnax 41:e58a5a09f411 9 // Notes and Instructions
nixnax 41:e58a5a09f411 10 // http://bit.ly/PPP-Blinky-Instructions
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 44:d0c61ae49ea5 20 // Wireshark - can't monitor Dial-Up network packets on windows, but useful - can import our dumpFrame routine's hex output
nixnax 29:30de79d658f6 21 // Microsoft network monitor - real-time monitoring of all our packets
nixnax 29:30de79d658f6 22 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 29:30de79d658f6 23 // 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 24 // 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 25 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 41:e58a5a09f411 26 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 41:e58a5a09f411 27
nixnax 81:9ede60e9a2c8 28 #include "mbed.h"
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 82:051f77f7dd72 32 #define SERIAL_PORT_MONITOR_NO /* or change to 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 83:cdcb81d1910f 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 81:9ede60e9a2c8 44 #define v1 0
nixnax 77:abf92baebb42 45 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 77:abf92baebb42 46 #define v2 0
nixnax 29:30de79d658f6 47
nixnax 66:f005b9fdf4d1 48 // this is the webpage we serve when we get an HTTP request
nixnax 72:ad3d12753acf 49 // keep size under 900 bytes to fit into a single frame
nixnax 66:f005b9fdf4d1 50 const static char ourWebPage[] = "\
nixnax 66:f005b9fdf4d1 51 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 52 <html>\
nixnax 66:f005b9fdf4d1 53 <head>\
nixnax 66:f005b9fdf4d1 54 <title>mbed-PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 55 <script>\
nixnax 66:f005b9fdf4d1 56 window.onload=function(){\
nixnax 66:f005b9fdf4d1 57 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 66:f005b9fdf4d1 58 x().textContent = parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 59 </script>\
nixnax 66:f005b9fdf4d1 60 </head>\
nixnax 66:f005b9fdf4d1 61 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 62 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 63 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 64 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 65 </body>\
nixnax 69:23f560087c16 66 </html>"; // around 464 bytes long
nixnax 69:23f560087c16 67
nixnax 69:23f560087c16 68
nixnax 66:f005b9fdf4d1 69
nixnax 73:2f56ec87dbe9 70 // 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 71 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 72:ad3d12753acf 72 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 73 // See instructions at the top.
nixnax 73:2f56ec87dbe9 74 // 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 75 Serial pc(USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax 29:30de79d658f6 76
nixnax 29:30de79d658f6 77 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 78
nixnax 66:f005b9fdf4d1 79 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 80 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 81
nixnax 29:30de79d658f6 82 // the serial port receive buffer and packet buffer
nixnax 0:2cf4880c312a 83
nixnax 29:30de79d658f6 84 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 85 struct pppType {
nixnax 38:ab582987926e 86 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 87 int ident; // our IP ident value
nixnax 38:ab582987926e 88 unsigned int seq; // our TCP sequence number
nixnax 38:ab582987926e 89 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 90 int ledState; // state of LED1
nixnax 84:456e73151f11 91 int httpFrame;
nixnax 4:a469050d5b80 92 struct {
nixnax 81:9ede60e9a2c8 93 #define RXBUFLEN (1<<14)
nixnax 81:9ede60e9a2c8 94 char buf[RXBUFLEN]; // RXBUFLEN MUST be a power of two because we use & operator for fast wrap-around in rxHandler
nixnax 72:ad3d12753acf 95 //char * buf;
nixnax 29:30de79d658f6 96 volatile int head;
nixnax 29:30de79d658f6 97 volatile int tail;
nixnax 81:9ede60e9a2c8 98 volatile int buflevel;
nixnax 38:ab582987926e 99 } rx; // serial port objects
nixnax 4:a469050d5b80 100 struct {
nixnax 38:ab582987926e 101 int len; // number of bytes in buffer
nixnax 38:ab582987926e 102 int crc; // PPP CRC (frame check)
nixnax 72:ad3d12753acf 103 //char * buf; // the actual buffer
nixnax 77:abf92baebb42 104 #define TCP_max_size 3300
nixnax 77:abf92baebb42 105 char buf[TCP_max_size]; // send and receive buffer large enough for unstuffed (decoded) hdlc frames
nixnax 38:ab582987926e 106 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 107 struct {
nixnax 50:ad4e7c3c88e5 108 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 109 int frameEndIndex; // frame end marker
nixnax 81:9ede60e9a2c8 110 int frameFound; // we have found at least one start of frame already
nixnax 50:ad4e7c3c88e5 111 } hdlc; // hdlc frame objects
nixnax 29:30de79d658f6 112 };
nixnax 31:e000c1b9c565 113
nixnax 29:30de79d658f6 114 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 115
nixnax 60:2b770949c911 116 // Initialize our globals
nixnax 29:30de79d658f6 117 void pppInitStruct()
nixnax 29:30de79d658f6 118 {
nixnax 81:9ede60e9a2c8 119 memset( ppp.rx.buf, 0, RXBUFLEN);
nixnax 29:30de79d658f6 120 ppp.online=0;
nixnax 81:9ede60e9a2c8 121 __disable_irq();
nixnax 29:30de79d658f6 122 ppp.rx.tail=0;
nixnax 29:30de79d658f6 123 ppp.rx.head=0;
nixnax 81:9ede60e9a2c8 124 __enable_irq();
nixnax 81:9ede60e9a2c8 125 ppp.rx.buflevel=0;
nixnax 29:30de79d658f6 126 ppp.pkt.len=0;
nixnax 83:cdcb81d1910f 127 ppp.ident=1000;
nixnax 29:30de79d658f6 128 ppp.ledState=0;
nixnax 81:9ede60e9a2c8 129 ppp.hdlc.frameFound=0;
nixnax 81:9ede60e9a2c8 130 ppp.hdlc.frameStartIndex=0;
nixnax 84:456e73151f11 131 ppp.httpFrame=0;
nixnax 29:30de79d658f6 132 }
nixnax 26:11f4eb2663a7 133
nixnax 43:aa57db08995d 134 void led1Toggle()
nixnax 43:aa57db08995d 135 {
nixnax 43:aa57db08995d 136 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 137 led1 = ppp.ledState;
nixnax 43:aa57db08995d 138 }
nixnax 43:aa57db08995d 139
nixnax 29:30de79d658f6 140 void crcReset()
nixnax 29:30de79d658f6 141 {
nixnax 29:30de79d658f6 142 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 143 }
nixnax 4:a469050d5b80 144
nixnax 29:30de79d658f6 145 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 146 {
nixnax 29:30de79d658f6 147 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 148 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 149 x>>=1;
nixnax 29:30de79d658f6 150 }
nixnax 29:30de79d658f6 151 }
nixnax 29:30de79d658f6 152
nixnax 29:30de79d658f6 153 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 154 {
nixnax 31:e000c1b9c565 155 crcReset();
nixnax 31:e000c1b9c565 156 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 157 return ppp.crc;
nixnax 29:30de79d658f6 158 }
nixnax 0:2cf4880c312a 159
nixnax 0:2cf4880c312a 160 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 161 {
nixnax 17:4918c893d802 162 while ( pc.readable() ) {
nixnax 81:9ede60e9a2c8 163 int hd = (ppp.rx.head+1)&(RXBUFLEN-1); // increment/wrap
nixnax 83:cdcb81d1910f 164 if ( hd == ppp.rx.tail ) {
nixnax 83:cdcb81d1910f 165 debug("Receive buffer is full. ppp.rx.buflevel = %d\n",ppp.rx.buflevel);
nixnax 83:cdcb81d1910f 166 break; // watch for buffer full
nixnax 83:cdcb81d1910f 167 }
nixnax 17:4918c893d802 168 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 169 ppp.rx.head = hd; // update head pointer
nixnax 81:9ede60e9a2c8 170 ppp.rx.buflevel++;
nixnax 15:b0154c910143 171 }
nixnax 0:2cf4880c312a 172 }
nixnax 0:2cf4880c312a 173
nixnax 22:00df34cd4d7e 174 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 175 {
nixnax 22:00df34cd4d7e 176 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 177 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 178 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 179 return emptyStatus;
nixnax 0:2cf4880c312a 180 }
nixnax 0:2cf4880c312a 181
nixnax 0:2cf4880c312a 182 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 183 {
nixnax 63:9253b0e1b7d8 184 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 81:9ede60e9a2c8 185 ppp.rx.tail=(ppp.rx.tail+1)&(RXBUFLEN-1);
nixnax 81:9ede60e9a2c8 186 ppp.rx.buflevel--;
nixnax 63:9253b0e1b7d8 187 return x;
nixnax 0:2cf4880c312a 188 }
nixnax 0:2cf4880c312a 189
nixnax 50:ad4e7c3c88e5 190 void processHDLCFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 191 {
nixnax 38:ab582987926e 192 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 193 if(start==end) {
nixnax 29:30de79d658f6 194 return;
nixnax 29:30de79d658f6 195 }
nixnax 9:0992486d4a30 196 crcReset();
nixnax 9:0992486d4a30 197 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 198 ppp.pkt.len=0;
nixnax 9:0992486d4a30 199 int unstuff=0;
nixnax 17:4918c893d802 200 int idx = start;
nixnax 17:4918c893d802 201 while(1) {
nixnax 9:0992486d4a30 202 if (unstuff==0) {
nixnax 72:ad3d12753acf 203 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 204 else {
nixnax 72:ad3d12753acf 205 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 206 ppp.pkt.len++;
nixnax 29:30de79d658f6 207 dest++;
nixnax 72:ad3d12753acf 208 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 209 }
nixnax 66:f005b9fdf4d1 210 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 211 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 212 ppp.pkt.len++;
nixnax 29:30de79d658f6 213 dest++;
nixnax 72:ad3d12753acf 214 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 215 unstuff=0;
nixnax 9:0992486d4a30 216 }
nixnax 81:9ede60e9a2c8 217 idx = (idx+1) & (RXBUFLEN-1);
nixnax 17:4918c893d802 218 if (idx == end) break;
nixnax 9:0992486d4a30 219 }
nixnax 29:30de79d658f6 220 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 221 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 222 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 223 determinePacketType();
nixnax 29:30de79d658f6 224 } else if (v0) {
nixnax 66:f005b9fdf4d1 225 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 226 }
nixnax 9:0992486d4a30 227 }
nixnax 9:0992486d4a30 228
nixnax 38:ab582987926e 229 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 230 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 231 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 232 void dumpFrame()
nixnax 29:30de79d658f6 233 {
nixnax 42:4de44be70bfd 234 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 235 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 236 }
nixnax 16:cb0b80c24ba2 237
nixnax 29:30de79d658f6 238 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 239 {
nixnax 29:30de79d658f6 240 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 241 pc.putc(0x7d);
nixnax 66:f005b9fdf4d1 242 pc.putc(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 243 } else {
nixnax 29:30de79d658f6 244 pc.putc(ch);
nixnax 29:30de79d658f6 245 }
nixnax 11:f58998c24f0b 246 }
nixnax 9:0992486d4a30 247
nixnax 66:f005b9fdf4d1 248 void sendFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 249 {
nixnax 17:4918c893d802 250 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 251 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 252 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 253 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 254 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 255 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 256 }
nixnax 9:0992486d4a30 257
nixnax 66:f005b9fdf4d1 258 void ipConfigRequestHandler()
nixnax 29:30de79d658f6 259 {
nixnax 64:677b9713a120 260 debug("IPCP Conf ");
nixnax 9:0992486d4a30 261 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 66:f005b9fdf4d1 262 debug("Rej\n"); // reject any options that are requested
nixnax 9:0992486d4a30 263 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 264 sendFrame();
nixnax 9:0992486d4a30 265 } else {
nixnax 64:677b9713a120 266 debug("Ack\n");
nixnax 9:0992486d4a30 267 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 268 sendFrame(); // acknowledge
nixnax 64:677b9713a120 269 debug("IPCP Ask\n");
nixnax 9:0992486d4a30 270 // send our own request now
nixnax 12:db0dc91f0231 271 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 272 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 273 sendFrame(); // this is our request
nixnax 9:0992486d4a30 274 }
nixnax 9:0992486d4a30 275 }
nixnax 9:0992486d4a30 276
nixnax 29:30de79d658f6 277 void ipAckHandler()
nixnax 29:30de79d658f6 278 {
nixnax 64:677b9713a120 279 debug("IPCP Grant\n");
nixnax 29:30de79d658f6 280 }
nixnax 9:0992486d4a30 281
nixnax 29:30de79d658f6 282 void ipNackHandler()
nixnax 29:30de79d658f6 283 {
nixnax 64:677b9713a120 284 debug("IPCP Nack\n");
nixnax 29:30de79d658f6 285 }
nixnax 9:0992486d4a30 286
nixnax 29:30de79d658f6 287 void ipDefaultHandler()
nixnax 29:30de79d658f6 288 {
nixnax 64:677b9713a120 289 debug("IPCP Other\n");
nixnax 29:30de79d658f6 290 }
nixnax 29:30de79d658f6 291
nixnax 29:30de79d658f6 292 void IPCPframe()
nixnax 29:30de79d658f6 293 {
nixnax 9:0992486d4a30 294 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 295 switch (code) {
nixnax 29:30de79d658f6 296 case 1:
nixnax 66:f005b9fdf4d1 297 ipConfigRequestHandler();
nixnax 29:30de79d658f6 298 break;
nixnax 29:30de79d658f6 299 case 2:
nixnax 29:30de79d658f6 300 ipAckHandler();
nixnax 29:30de79d658f6 301 break;
nixnax 29:30de79d658f6 302 case 3:
nixnax 29:30de79d658f6 303 ipNackHandler();
nixnax 29:30de79d658f6 304 break;
nixnax 29:30de79d658f6 305 default:
nixnax 29:30de79d658f6 306 ipDefaultHandler();
nixnax 9:0992486d4a30 307 }
nixnax 29:30de79d658f6 308 }
nixnax 9:0992486d4a30 309
nixnax 29:30de79d658f6 310 void UDPpacket()
nixnax 29:30de79d658f6 311 {
nixnax 12:db0dc91f0231 312 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 313 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 314 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 63:9253b0e1b7d8 315 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 316 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 317 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 318 #endif
nixnax 12:db0dc91f0231 319 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 320 char * udpInf = udpBlock+8; // actual start of info
nixnax 63:9253b0e1b7d8 321 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 322 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 323 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 324 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 325 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 326 #endif
nixnax 29:30de79d658f6 327 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 328 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 81:9ede60e9a2c8 329 if(v0) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 81:9ede60e9a2c8 330 if(v0) debug("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 83:cdcb81d1910f 331 if(v0) debug("Len %03d", udpLength);
nixnax 29:30de79d658f6 332 int printSize = udpLength;
nixnax 29:30de79d658f6 333 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 81:9ede60e9a2c8 334 if (v1) {
nixnax 29:30de79d658f6 335 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 336 char ch = udpInf[i];
nixnax 29:30de79d658f6 337 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 338 debug("%c", ch);
nixnax 29:30de79d658f6 339 } else {
nixnax 64:677b9713a120 340 debug("_");
nixnax 29:30de79d658f6 341 }
nixnax 29:30de79d658f6 342 }
nixnax 29:30de79d658f6 343 }
nixnax 83:cdcb81d1910f 344 if (v0) debug("\n");
nixnax 12:db0dc91f0231 345 }
nixnax 11:f58998c24f0b 346
nixnax 76:00e208cceb8b 347 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 348 {
nixnax 77:abf92baebb42 349
nixnax 75:0d513869231f 350 unsigned int sum=0;
nixnax 76:00e208cceb8b 351 unsigned char placeHolder;
nixnax 29:30de79d658f6 352 if (len&1) {
nixnax 76:00e208cceb8b 353 placeHolder = ptr[len]; // when length is odd stuff in a zero byte
nixnax 76:00e208cceb8b 354 ptr[len]=0;
nixnax 29:30de79d658f6 355 }
nixnax 29:30de79d658f6 356 for (int i=0; i<len/2; i++) {
nixnax 76:00e208cceb8b 357 unsigned int hi = *ptr;
nixnax 29:30de79d658f6 358 ptr++;
nixnax 76:00e208cceb8b 359 unsigned int lo = *ptr;
nixnax 29:30de79d658f6 360 ptr++;
nixnax 76:00e208cceb8b 361 unsigned int val = ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 362 sum = sum + val;
nixnax 11:f58998c24f0b 363 }
nixnax 29:30de79d658f6 364 if (len&1) {
nixnax 76:00e208cceb8b 365 ptr[len] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 366 }
nixnax 76:00e208cceb8b 367 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 368 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 369 return ~sum;
nixnax 29:30de79d658f6 370 }
nixnax 11:f58998c24f0b 371
nixnax 29:30de79d658f6 372 void headerCheckSum()
nixnax 29:30de79d658f6 373 {
nixnax 11:f58998c24f0b 374 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 375 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 376 int sum=0;
nixnax 11:f58998c24f0b 377
nixnax 29:30de79d658f6 378 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 379 int hi = *ptr;
nixnax 29:30de79d658f6 380 ptr++;
nixnax 29:30de79d658f6 381 int lo = *ptr;
nixnax 29:30de79d658f6 382 ptr++;
nixnax 11:f58998c24f0b 383 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 384 sum = sum + val;
nixnax 11:f58998c24f0b 385 }
nixnax 11:f58998c24f0b 386 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 387 sum = ~sum;
nixnax 11:f58998c24f0b 388 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 389 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 390 }
nixnax 9:0992486d4a30 391
nixnax 29:30de79d658f6 392 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 393 {
nixnax 12:db0dc91f0231 394 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 395 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 396 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 397 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 398 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 399 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 400 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 401 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 402 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 403 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 404 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 405 char * dstAdr = ipPkt+16;
nixnax 63:9253b0e1b7d8 406 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 407 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 408 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 63:9253b0e1b7d8 409 #endif
nixnax 81:9ede60e9a2c8 410 if(v0) 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 81:9ede60e9a2c8 411 if(v0) debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 412 char src[4];
nixnax 29:30de79d658f6 413 char dst[4];
nixnax 12:db0dc91f0231 414 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 415 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 416 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 417 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 418 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 419 chkSum[0]=0;
nixnax 29:30de79d658f6 420 chkSum[1]=0;
nixnax 12:db0dc91f0231 421 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 422 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 423 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 424 icmpSum[0]=0;
nixnax 29:30de79d658f6 425 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 426 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 427 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 428 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 429 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 430
nixnax 16:cb0b80c24ba2 431 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 432 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 433 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 434 if (v0) {
nixnax 29:30de79d658f6 435 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 436 char ch = icmpData[i];
nixnax 29:30de79d658f6 437 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 438 debug("%c",ch);
nixnax 29:30de79d658f6 439 } else {
nixnax 64:677b9713a120 440 debug("_");
nixnax 29:30de79d658f6 441 }
nixnax 29:30de79d658f6 442 }
nixnax 64:677b9713a120 443 debug("\n");
nixnax 29:30de79d658f6 444 }
nixnax 15:b0154c910143 445 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 446
nixnax 12:db0dc91f0231 447 } else {
nixnax 29:30de79d658f6 448 if (v0) {
nixnax 42:4de44be70bfd 449 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 450 }
nixnax 11:f58998c24f0b 451 }
nixnax 11:f58998c24f0b 452 }
nixnax 11:f58998c24f0b 453
nixnax 29:30de79d658f6 454 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 455 {
nixnax 29:30de79d658f6 456 if (v0) {
nixnax 42:4de44be70bfd 457 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 458 }
nixnax 29:30de79d658f6 459 }
nixnax 11:f58998c24f0b 460
nixnax 29:30de79d658f6 461 void dumpHeaderIP ()
nixnax 29:30de79d658f6 462 {
nixnax 26:11f4eb2663a7 463 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 464 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 465 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 466 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 467 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 468 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 469 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 470 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 471 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 472 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 473 char * protocol = ipPkt+9; // 1 byte
nixnax 77:abf92baebb42 474 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 475 #endif
nixnax 26:11f4eb2663a7 476 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 477 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 478
nixnax 55:43faae812be3 479 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 480 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 481 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 482 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 483 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 484 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 485 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 486 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 487 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 488 int protocolIP = protocol[0];
nixnax 76:00e208cceb8b 489 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 490 #endif
nixnax 55:43faae812be3 491
nixnax 29:30de79d658f6 492 char srcIP [16];
nixnax 29:30de79d658f6 493 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 494 char dstIP [16];
nixnax 29:30de79d658f6 495 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 82:051f77f7dd72 496 if (v0) debug("IP %s %s v%d h%d d%d e%d L%03d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 42:4de44be70bfd 497 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 498 }
nixnax 26:11f4eb2663a7 499
nixnax 29:30de79d658f6 500 void dumpHeaderTCP()
nixnax 29:30de79d658f6 501 {
nixnax 83:cdcb81d1910f 502 if( v0 ) {
nixnax 81:9ede60e9a2c8 503
nixnax 81:9ede60e9a2c8 504 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 81:9ede60e9a2c8 505 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 63:9253b0e1b7d8 506 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 81:9ede60e9a2c8 507 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 81:9ede60e9a2c8 508 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 63:9253b0e1b7d8 509 #endif
nixnax 81:9ede60e9a2c8 510 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 63:9253b0e1b7d8 511 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 81:9ede60e9a2c8 512 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 81:9ede60e9a2c8 513 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 63:9253b0e1b7d8 514 #endif
nixnax 81:9ede60e9a2c8 515 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 516
nixnax 81:9ede60e9a2c8 517 char flagInfo[10]; // text string presentating the TCP flags
nixnax 81:9ede60e9a2c8 518 memset(flagInfo,'.', 9); // fill string with "........."
nixnax 81:9ede60e9a2c8 519 memset(flagInfo+9,0,1); // null terminate string
nixnax 66:f005b9fdf4d1 520
nixnax 81:9ede60e9a2c8 521 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 81:9ede60e9a2c8 522 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 81:9ede60e9a2c8 523 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 81:9ede60e9a2c8 524 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 81:9ede60e9a2c8 525 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 81:9ede60e9a2c8 526 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 81:9ede60e9a2c8 527 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 81:9ede60e9a2c8 528 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 81:9ede60e9a2c8 529 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 81:9ede60e9a2c8 530 debug("TCP Flags %s Seq %u Ack %u\n", flagInfo, seq, ack); // show the flags in debug
nixnax 29:30de79d658f6 531 }
nixnax 29:30de79d658f6 532 }
nixnax 29:30de79d658f6 533
nixnax 68:0b74763ae67f 534 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 535 {
nixnax 67:a63e3486bcda 536 int n=0; // number of bytes we have printed so far
nixnax 77:abf92baebb42 537 int nHeader; // byte size of HTTP header
nixnax 83:cdcb81d1910f 538 int contentLengthStart; // index where HTML starts
nixnax 84:456e73151f11 539
nixnax 84:456e73151f11 540 ppp.httpFrame++; // increment count of response frames
nixnax 84:456e73151f11 541
nixnax 84:456e73151f11 542 int rootFetch = strncmp(dataStart, "GET / HTTP/1.1", 14);
nixnax 77:abf92baebb42 543
nixnax 84:456e73151f11 544 if( rootFetch == 0 ) {
nixnax 67:a63e3486bcda 545 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 83:cdcb81d1910f 546 } else {
nixnax 67:a63e3486bcda 547 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 83:cdcb81d1910f 548 }
nixnax 83:cdcb81d1910f 549
nixnax 83:cdcb81d1910f 550 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 83:cdcb81d1910f 551 contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 83:cdcb81d1910f 552 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 83:cdcb81d1910f 553 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 83:cdcb81d1910f 554 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 555 nHeader=n; // size of HTTP header
nixnax 67:a63e3486bcda 556
nixnax 84:456e73151f11 557 if( rootFetch == 0 ) {
nixnax 83:cdcb81d1910f 558 // this is where we insert our web page into the buffer
nixnax 83:cdcb81d1910f 559 n=n+sprintf(n+dataStart,"%s", ourWebPage);
nixnax 83:cdcb81d1910f 560 } else {
nixnax 83:cdcb81d1910f 561 // all other requests get 404 Not Found response a
nixnax 84:456e73151f11 562 n=n+sprintf(n+dataStart,"<!DOCTYPE html>"); // html start
nixnax 84:456e73151f11 563 n=n+sprintf(n+dataStart,"<title>%06d</title>",ppp.httpFrame); // shortest possible valid frame
nixnax 83:cdcb81d1910f 564 }
nixnax 83:cdcb81d1910f 565
nixnax 83:cdcb81d1910f 566 while( (n%4)!= 2)
nixnax 83:cdcb81d1910f 567 n=n+sprintf(n+dataStart," "); // insert spaces until n is exactly two away from a multiple of four
nixnax 83:cdcb81d1910f 568 n=n+sprintf(n+dataStart,"\r\n"); // add the last \r\n sequence - n is now an exact multiple of four
nixnax 83:cdcb81d1910f 569 #define CONTENTLENGTHSIZE 5
nixnax 83:cdcb81d1910f 570 char contentLengthString[CONTENTLENGTHSIZE+1];
nixnax 83:cdcb81d1910f 571 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 83:cdcb81d1910f 572 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 573
nixnax 77:abf92baebb42 574 if (v2) {
nixnax 77:abf92baebb42 575 debug("HTTP Response: HTTP-header %d HTTP-content %d HTTP-total %d\n",nHeader,n-nHeader,n);
nixnax 77:abf92baebb42 576 }
nixnax 67:a63e3486bcda 577 return n; // total byte size of our response
nixnax 67:a63e3486bcda 578 }
nixnax 67:a63e3486bcda 579
nixnax 67:a63e3486bcda 580
nixnax 29:30de79d658f6 581 void tcpHandler()
nixnax 29:30de79d658f6 582 {
nixnax 26:11f4eb2663a7 583 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 584 char * ihl = ipPkt; // bottom 4 bits
nixnax 83:cdcb81d1910f 585 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 586 char * ident = ipPkt+4; // 2 bytes
nixnax 28:1aa629be05e7 587 char * protocol = ipPkt+9; // 1 byte
nixnax 83:cdcb81d1910f 588 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 589 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 590 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 591 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 592 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 593
nixnax 29:30de79d658f6 594 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 595 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 596 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 597 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 598 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 599 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 600 char * flagbitstcp = s + 12; // 9 bits
nixnax 82:051f77f7dd72 601 char * windowsizetcp = s + 14; // 2 bytes
nixnax 26:11f4eb2663a7 602 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 603
nixnax 26:11f4eb2663a7 604 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 605 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 606 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 607
nixnax 35:e7068df4d971 608 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 609
nixnax 35:e7068df4d971 610 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 611 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 81:9ede60e9a2c8 612
nixnax 77:abf92baebb42 613 unsigned int ack = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]) + tcpDataSize;
nixnax 79:f0fc1c19a550 614 unsigned int seq = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]); // use their idea of our seq
nixnax 81:9ede60e9a2c8 615
nixnax 28:1aa629be05e7 616
nixnax 29:30de79d658f6 617 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 618 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 619 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 620 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 621 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 622
nixnax 35:e7068df4d971 623 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 624 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 625 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 626
nixnax 69:23f560087c16 627 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 69:23f560087c16 628 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 69:23f560087c16 629 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 77:abf92baebb42 630
nixnax 69:23f560087c16 631 switch ( flagsTCP ) {
nixnax 69:23f560087c16 632 case TCP_FLAG_ACK:
nixnax 69:23f560087c16 633 if ( tcpDataSize != 1 ) return;
nixnax 79:f0fc1c19a550 634 ack++;
nixnax 69:23f560087c16 635 case TCP_FLAG_SYN:
nixnax 82:051f77f7dd72 636 // ignore all TCP options by shortening packet to 40 bytes
nixnax 82:051f77f7dd72 637 pktLen[1] = 40; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 638 packetLength = 40; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 639 headerSizeTCP = 20; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 640 tcpSize = 20; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 641 headerSizeTCP = 20; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 642 offset[0] = (headerSizeTCP/4)<<4; // shorten packet to 40 bytes
nixnax 82:051f77f7dd72 643
nixnax 69:23f560087c16 644 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - ack it
nixnax 81:9ede60e9a2c8 645 ppp.seq = ppp.seq + 10000; // create a new sequence number (normally random)
nixnax 79:f0fc1c19a550 646 seq = ppp.seq; // create a new sequence number (normally random)
nixnax 79:f0fc1c19a550 647 ack++; // for SYN flag we have to increase their sequence by 1
nixnax 69:23f560087c16 648 break;
nixnax 77:abf92baebb42 649 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 69:23f560087c16 650 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 69:23f560087c16 651 fastResponse = 1; // we can respond fast to a push
nixnax 69:23f560087c16 652 if ( strncmp(dataStart, "GET ", 4) == 0) { // do we see an http GET command
nixnax 69:23f560087c16 653 dataLen = httpResponse(dataStart); // send an http response
nixnax 69:23f560087c16 654 while((dataLen %4 ) !=0) { // dataLen must be a multiple of four
nixnax 77:abf92baebb42 655 dataLen++; // must be a multiple of four
nixnax 77:abf92baebb42 656 dataStart[dataLen-1]=0; // clear the byte in the buffer
nixnax 80:753f5dd2e84e 657 ack++;
nixnax 69:23f560087c16 658 }
nixnax 69:23f560087c16 659 }
nixnax 69:23f560087c16 660 break;
nixnax 77:abf92baebb42 661 case TCP_FLAG_FIN:
nixnax 69:23f560087c16 662 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 69:23f560087c16 663 case TCP_FLAG_FIN | TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 77:abf92baebb42 664 ack++; // for FIN flag we have to increase sequence by 1
nixnax 69:23f560087c16 665 break;
nixnax 77:abf92baebb42 666 default:
nixnax 69:23f560087c16 667 return; // ignore remaining packets
nixnax 28:1aa629be05e7 668 }
nixnax 81:9ede60e9a2c8 669
nixnax 77:abf92baebb42 670
nixnax 69:23f560087c16 671 // The TCP flag handling is now done
nixnax 38:ab582987926e 672 // 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 673
nixnax 83:cdcb81d1910f 674 ppp.ident++; //
nixnax 83:cdcb81d1910f 675 ident[0] = ppp.ident>>8;
nixnax 83:cdcb81d1910f 676 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 83:cdcb81d1910f 677
nixnax 65:23b17c43aa0f 678 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 679 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 680 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 681 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 682
nixnax 60:2b770949c911 683 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 684 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 685 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 83:cdcb81d1910f 686
nixnax 82:051f77f7dd72 687 windowsizetcp[0]=16; // ignore window size negotiation
nixnax 82:051f77f7dd72 688 windowsizetcp[1]=0; // ignore winodw size negotiation
nixnax 29:30de79d658f6 689
nixnax 38:ab582987926e 690 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 691 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 692 acktcp[2]=ack>>8;
nixnax 67:a63e3486bcda 693 acktcp[3]=ack>>0; // save ack 32-bit integer
nixnax 38:ab582987926e 694
nixnax 38:ab582987926e 695 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 696 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 697 seqtcp[2]=seq>>8;
nixnax 67:a63e3486bcda 698 seqtcp[3]=seq>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 699
nixnax 38:ab582987926e 700 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 701
nixnax 38:ab582987926e 702 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 703 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 704 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 705 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 706 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 707
nixnax 38:ab582987926e 708 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 709
nixnax 61:b3c1a04efd0a 710 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 711 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 712 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 713
nixnax 64:677b9713a120 714 // 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 715 // 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 716
nixnax 62:f192926e42f1 717 char * pseudoHeader = s-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 718 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 719 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 720 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 721 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 722 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 723 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 724
nixnax 61:b3c1a04efd0a 725 // pseudo-header built, now we can calculate TCP checksum
nixnax 63:9253b0e1b7d8 726
nixnax 29:30de79d658f6 727 checksumtcp[0]=0;
nixnax 29:30de79d658f6 728 checksumtcp[1]=0;
nixnax 76:00e208cceb8b 729 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 730 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 731 checksumtcp[1]=pseudoHeaderSum;
nixnax 61:b3c1a04efd0a 732 memcpy( s-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 60:2b770949c911 733
nixnax 36:2a9b457f8276 734 if (fastResponse==1) {
nixnax 36:2a9b457f8276 735 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 736 } else {
nixnax 81:9ede60e9a2c8 737 // normally, you wait 200 ms before responding to a TCP packet
nixnax 68:0b74763ae67f 738 // remove the wait to respond faster
nixnax 78:809c2631a5eb 739 // wait(0.2);
nixnax 36:2a9b457f8276 740 }
nixnax 83:cdcb81d1910f 741 sendFrame(); // All preparation complete - send the TCP response
nixnax 83:cdcb81d1910f 742 dumpHeaderIP();
nixnax 81:9ede60e9a2c8 743 dumpHeaderTCP();
nixnax 29:30de79d658f6 744 }
nixnax 26:11f4eb2663a7 745
nixnax 29:30de79d658f6 746 void dumpDataTCP()
nixnax 29:30de79d658f6 747 {
nixnax 26:11f4eb2663a7 748 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 749 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 750 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 751 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 752 if (v1) {
nixnax 42:4de44be70bfd 753 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 754 }
nixnax 29:30de79d658f6 755 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 756 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 757 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 758 }
nixnax 29:30de79d658f6 759 }
nixnax 26:11f4eb2663a7 760
nixnax 29:30de79d658f6 761 void TCPpacket()
nixnax 29:30de79d658f6 762 {
nixnax 83:cdcb81d1910f 763 dumpHeaderIP();
nixnax 81:9ede60e9a2c8 764 dumpHeaderTCP();
nixnax 77:abf92baebb42 765 if (v2) {
nixnax 77:abf92baebb42 766 dumpDataTCP();
nixnax 77:abf92baebb42 767 }
nixnax 26:11f4eb2663a7 768 tcpHandler();
nixnax 11:f58998c24f0b 769 }
nixnax 11:f58998c24f0b 770
nixnax 29:30de79d658f6 771 void otherProtocol()
nixnax 29:30de79d658f6 772 {
nixnax 64:677b9713a120 773 debug("Other IP protocol");
nixnax 29:30de79d658f6 774 }
nixnax 26:11f4eb2663a7 775
nixnax 29:30de79d658f6 776 void IPframe()
nixnax 29:30de79d658f6 777 {
nixnax 10:74f8233f72c0 778 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 779 switch (protocol) {
nixnax 29:30de79d658f6 780 case 1:
nixnax 29:30de79d658f6 781 ICMPpacket();
nixnax 29:30de79d658f6 782 break;
nixnax 29:30de79d658f6 783 case 2:
nixnax 29:30de79d658f6 784 IGMPpacket();
nixnax 29:30de79d658f6 785 break;
nixnax 29:30de79d658f6 786 case 17:
nixnax 29:30de79d658f6 787 UDPpacket();
nixnax 29:30de79d658f6 788 break;
nixnax 29:30de79d658f6 789 case 6:
nixnax 29:30de79d658f6 790 TCPpacket();
nixnax 29:30de79d658f6 791 break;
nixnax 29:30de79d658f6 792 default:
nixnax 29:30de79d658f6 793 otherProtocol();
nixnax 29:30de79d658f6 794 }
nixnax 29:30de79d658f6 795 }
nixnax 9:0992486d4a30 796
nixnax 29:30de79d658f6 797 void LCPconfReq()
nixnax 29:30de79d658f6 798 {
nixnax 64:677b9713a120 799 debug("LCP Config ");
nixnax 9:0992486d4a30 800 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 801 ppp.pkt.buf[4]=4; // allow only no options
nixnax 64:677b9713a120 802 debug("Reject\n");
nixnax 29:30de79d658f6 803 sendFrame();
nixnax 9:0992486d4a30 804 } else {
nixnax 9:0992486d4a30 805 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 64:677b9713a120 806 debug("Ack\n");
nixnax 9:0992486d4a30 807 sendFrame();
nixnax 64:677b9713a120 808 debug("LCP Ask\n");
nixnax 11:f58998c24f0b 809 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 810 sendFrame();
nixnax 9:0992486d4a30 811 }
nixnax 9:0992486d4a30 812 }
nixnax 9:0992486d4a30 813
nixnax 29:30de79d658f6 814 void LCPconfAck()
nixnax 29:30de79d658f6 815 {
nixnax 64:677b9713a120 816 debug("LCP Ack\n");
nixnax 29:30de79d658f6 817 }
nixnax 9:0992486d4a30 818
nixnax 29:30de79d658f6 819 void LCPend()
nixnax 29:30de79d658f6 820 {
nixnax 29:30de79d658f6 821 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 822 sendFrame(); // acknowledge
nixnax 81:9ede60e9a2c8 823 ppp.online=0; // start hunting for connect string again
nixnax 81:9ede60e9a2c8 824 pppInitStruct(); // flush the receive buffer
nixnax 81:9ede60e9a2c8 825 debug("LCP End\n");
nixnax 9:0992486d4a30 826 }
nixnax 9:0992486d4a30 827
nixnax 29:30de79d658f6 828 void LCPother()
nixnax 29:30de79d658f6 829 {
nixnax 64:677b9713a120 830 debug("LCP Other\n");
nixnax 29:30de79d658f6 831 dumpFrame();
nixnax 29:30de79d658f6 832 }
nixnax 29:30de79d658f6 833
nixnax 29:30de79d658f6 834 void LCPframe()
nixnax 29:30de79d658f6 835 {
nixnax 29:30de79d658f6 836 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 837 switch (code) {
nixnax 29:30de79d658f6 838 case 1:
nixnax 29:30de79d658f6 839 LCPconfReq();
nixnax 29:30de79d658f6 840 break; // config request
nixnax 29:30de79d658f6 841 case 2:
nixnax 29:30de79d658f6 842 LCPconfAck();
nixnax 29:30de79d658f6 843 break; // config ack
nixnax 29:30de79d658f6 844 case 5:
nixnax 29:30de79d658f6 845 LCPend();
nixnax 29:30de79d658f6 846 break; // end connection
nixnax 29:30de79d658f6 847 default:
nixnax 29:30de79d658f6 848 LCPother();
nixnax 29:30de79d658f6 849 }
nixnax 9:0992486d4a30 850 }
nixnax 9:0992486d4a30 851
nixnax 29:30de79d658f6 852 void discardedFrame()
nixnax 29:30de79d658f6 853 {
nixnax 29:30de79d658f6 854 if (v0) {
nixnax 71:965619fedb3a 855 debug("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 856 }
nixnax 9:0992486d4a30 857 }
nixnax 9:0992486d4a30 858
nixnax 29:30de79d658f6 859 void determinePacketType()
nixnax 29:30de79d658f6 860 {
nixnax 29:30de79d658f6 861 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 64:677b9713a120 862 debug("byte0 != ff\n");
nixnax 29:30de79d658f6 863 return;
nixnax 29:30de79d658f6 864 }
nixnax 29:30de79d658f6 865 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 64:677b9713a120 866 debug("byte1 != 3\n");
nixnax 29:30de79d658f6 867 return;
nixnax 29:30de79d658f6 868 }
nixnax 29:30de79d658f6 869 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 64:677b9713a120 870 debug("byte2 != 21\n");
nixnax 29:30de79d658f6 871 return;
nixnax 29:30de79d658f6 872 }
nixnax 9:0992486d4a30 873 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 874 switch (packetType) {
nixnax 29:30de79d658f6 875 case 0xc0:
nixnax 29:30de79d658f6 876 LCPframe();
nixnax 29:30de79d658f6 877 break; // link control
nixnax 29:30de79d658f6 878 case 0x80:
nixnax 29:30de79d658f6 879 IPCPframe();
nixnax 29:30de79d658f6 880 break; // IP control
nixnax 29:30de79d658f6 881 case 0x00:
nixnax 29:30de79d658f6 882 IPframe();
nixnax 29:30de79d658f6 883 break; // IP itself
nixnax 29:30de79d658f6 884 default:
nixnax 29:30de79d658f6 885 discardedFrame();
nixnax 9:0992486d4a30 886 }
nixnax 29:30de79d658f6 887 }
nixnax 9:0992486d4a30 888
nixnax 50:ad4e7c3c88e5 889 void wait_for_HDLC_frame()
nixnax 50:ad4e7c3c88e5 890 {
nixnax 81:9ede60e9a2c8 891 while(1)
nixnax 81:9ede60e9a2c8 892 if ( rxbufNotEmpty() ) {
nixnax 81:9ede60e9a2c8 893 int oldTail = ppp.rx.tail; // remember where the character is located in the buffer
nixnax 81:9ede60e9a2c8 894 int rx = pc_getBuf(); // get the character
nixnax 50:ad4e7c3c88e5 895 if (rx==FRAME_7E) {
nixnax 81:9ede60e9a2c8 896 if (ppp.hdlc.frameFound == 0) { // we are still waiting for a frame start
nixnax 81:9ede60e9a2c8 897 ppp.hdlc.frameFound = 1; // we found our first frame start
nixnax 81:9ede60e9a2c8 898 ppp.hdlc.frameStartIndex=ppp.rx.tail; // remember where the frame character is in the buffer
nixnax 51:a86d56844324 899 } else {
nixnax 81:9ede60e9a2c8 900 // we have previously found a frame start
nixnax 81:9ede60e9a2c8 901 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
nixnax 81:9ede60e9a2c8 902 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
nixnax 81:9ede60e9a2c8 903 ppp.hdlc.frameStartIndex = ppp.rx.tail; // where next frame will start
nixnax 81:9ede60e9a2c8 904 break;
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 81:9ede60e9a2c8 912 while(ppp.online == 0) {
nixnax 81:9ede60e9a2c8 913 // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 81:9ede60e9a2c8 914 char * found1 = strstr( (char *)ppp.rx.buf, "CLIENTCLIENT" );
nixnax 81:9ede60e9a2c8 915 // also search for HDLC frame start character 0x7e
nixnax 81:9ede60e9a2c8 916 void * found2 = memchr( (char *)ppp.rx.buf, 0x7e, RXBUFLEN );
nixnax 81:9ede60e9a2c8 917 if( (found1 != NULL) | (found2 != NULL) ) {
nixnax 81:9ede60e9a2c8 918 if (found1 != NULL) {
nixnax 82:051f77f7dd72 919 memset(ppp.rx.buf, 0x20, RXBUFLEN); // clear the receive buffer
nixnax 81:9ede60e9a2c8 920 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 81:9ede60e9a2c8 921 pc.puts("CLIENTSERVER");
nixnax 81:9ede60e9a2c8 922 if (v0) debug("Found connect string \"CLIENTCLIENT\"\n");
nixnax 81:9ede60e9a2c8 923 }
nixnax 81:9ede60e9a2c8 924 if (found2 != NULL) {
nixnax 81:9ede60e9a2c8 925 if (v0) debug("Found HDLC frame start (7E)\n");
nixnax 81:9ede60e9a2c8 926 }
nixnax 71:965619fedb3a 927 ppp.online=1; // we are connected, so stop looking for the string
nixnax 9:0992486d4a30 928 }
nixnax 9:0992486d4a30 929 }
nixnax 81:9ede60e9a2c8 930
nixnax 9:0992486d4a30 931 }
nixnax 9:0992486d4a30 932
nixnax 0:2cf4880c312a 933 int main()
nixnax 0:2cf4880c312a 934 {
nixnax 14:c65831c25aaa 935 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 936 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 49:2213f9c132b2 937 xx.baud(115200); // second serial port for debug messages
nixnax 9:0992486d4a30 938 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 939 #endif
nixnax 9:0992486d4a30 940 pppInitStruct(); // initialize all the PPP properties
nixnax 81:9ede60e9a2c8 941 ppp.seq=1000; // initial TCP sequence number
nixnax 81:9ede60e9a2c8 942
nixnax 9:0992486d4a30 943 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 0:2cf4880c312a 944 while(1) {
nixnax 51:a86d56844324 945 scanForConnectString(); // respond to connect command from windows dial up networking
nixnax 81:9ede60e9a2c8 946 while(ppp.online) {
nixnax 81:9ede60e9a2c8 947 wait_for_HDLC_frame();
nixnax 81:9ede60e9a2c8 948 }
nixnax 7:ab147f5e97ac 949 }
nixnax 7:ab147f5e97ac 950 }