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@72:ad3d12753acf, 2017-06-17 (annotated)

Committer:
nixnax
Date:
Sat Jun 17 20:25:39 2017 +0000
Revision:
72:ad3d12753acf
Parent:
71:965619fedb3a
Child:
73:2f56ec87dbe9
Moved globals into ppp structure; Latest mbed lib; 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 72:ad3d12753acf 6 // A Tiny Webserver Using Windows XP/7/8/10 Dial-Up 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 72:ad3d12753acf 47 // keep size under 900 bytes to fit into 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 69:23f560087c16 64 </html>"; // around 464 bytes long
nixnax 69:23f560087c16 65
nixnax 69:23f560087c16 66
nixnax 66:f005b9fdf4d1 67
nixnax 72:ad3d12753acf 68 // The serial port on your mbed hardware. Your PC should view this as a standard dial-up networking modem.
nixnax 72:ad3d12753acf 69 // The modem type on windows should be selected as "Direct communication between two computers"
nixnax 72:ad3d12753acf 70 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 71 // See instructions at the top.
nixnax 66:f005b9fdf4d1 72 // On a typical mbed hardware platform this is a USB virtual com port (VCP)
nixnax 66:f005b9fdf4d1 73 Serial pc(USBTX, USBRX); // usb virtual com port
nixnax 29:30de79d658f6 74
nixnax 29:30de79d658f6 75 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 76
nixnax 66:f005b9fdf4d1 77 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 78 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 79
nixnax 29:30de79d658f6 80 // the serial port receive buffer and packet buffer
nixnax 0:2cf4880c312a 81
nixnax 29:30de79d658f6 82 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 83 struct pppType {
nixnax 38:ab582987926e 84 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 85 int ident; // our IP ident value
nixnax 38:ab582987926e 86 unsigned int seq; // our TCP sequence number
nixnax 38:ab582987926e 87 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 88 int ledState; // state of LED1
nixnax 4:a469050d5b80 89 struct {
nixnax 72:ad3d12753acf 90 #define BUFLEN (1<<13)
nixnax 72:ad3d12753acf 91 char buf[BUFLEN]; // BUFLEN MUST be a power of two because we use & operator for fast wrap-around in rxHandler
nixnax 72:ad3d12753acf 92 //char * buf;
nixnax 29:30de79d658f6 93 volatile int head;
nixnax 29:30de79d658f6 94 volatile int tail;
nixnax 38:ab582987926e 95 } rx; // serial port objects
nixnax 4:a469050d5b80 96 struct {
nixnax 38:ab582987926e 97 int len; // number of bytes in buffer
nixnax 38:ab582987926e 98 int crc; // PPP CRC (frame check)
nixnax 72:ad3d12753acf 99 //char * buf; // the actual buffer
nixnax 72:ad3d12753acf 100 char buf[3300]; // send and receive buffer large enough for unstuffed (decoded) hdlc frames
nixnax 38:ab582987926e 101 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 102 struct {
nixnax 50:ad4e7c3c88e5 103 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 104 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 105 int frameBusy; // busy capturing a frame
nixnax 50:ad4e7c3c88e5 106 } hdlc; // hdlc frame objects
nixnax 29:30de79d658f6 107 };
nixnax 31:e000c1b9c565 108
nixnax 29:30de79d658f6 109 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 110
nixnax 60:2b770949c911 111 // Initialize our globals
nixnax 29:30de79d658f6 112 void pppInitStruct()
nixnax 29:30de79d658f6 113 {
nixnax 29:30de79d658f6 114 ppp.online=0;
nixnax 72:ad3d12753acf 115 //ppp.rx.buf=rxbufppp;
nixnax 29:30de79d658f6 116 ppp.rx.tail=0;
nixnax 29:30de79d658f6 117 ppp.rx.head=0;
nixnax 72:ad3d12753acf 118 //ppp.pkt.buf=hdlcBuffer;
nixnax 29:30de79d658f6 119 ppp.pkt.len=0;
nixnax 29:30de79d658f6 120 ppp.ident=0;
nixnax 35:e7068df4d971 121 ppp.seq=1000;
nixnax 29:30de79d658f6 122 ppp.ledState=0;
nixnax 50:ad4e7c3c88e5 123 ppp.hdlc.frameBusy=0;
nixnax 29:30de79d658f6 124 }
nixnax 26:11f4eb2663a7 125
nixnax 43:aa57db08995d 126 void led1Toggle()
nixnax 43:aa57db08995d 127 {
nixnax 43:aa57db08995d 128 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 129 led1 = ppp.ledState;
nixnax 43:aa57db08995d 130 }
nixnax 43:aa57db08995d 131
nixnax 29:30de79d658f6 132 void crcReset()
nixnax 29:30de79d658f6 133 {
nixnax 29:30de79d658f6 134 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 135 }
nixnax 4:a469050d5b80 136
nixnax 29:30de79d658f6 137 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 138 {
nixnax 29:30de79d658f6 139 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 140 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 141 x>>=1;
nixnax 29:30de79d658f6 142 }
nixnax 29:30de79d658f6 143 }
nixnax 29:30de79d658f6 144
nixnax 29:30de79d658f6 145 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 146 {
nixnax 31:e000c1b9c565 147 crcReset();
nixnax 31:e000c1b9c565 148 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 149 return ppp.crc;
nixnax 29:30de79d658f6 150 }
nixnax 0:2cf4880c312a 151
nixnax 0:2cf4880c312a 152 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 153 {
nixnax 17:4918c893d802 154 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 155 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 156 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 157 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 158 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 159 }
nixnax 0:2cf4880c312a 160 }
nixnax 0:2cf4880c312a 161
nixnax 22:00df34cd4d7e 162 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 163 {
nixnax 22:00df34cd4d7e 164 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 165 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 166 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 167 return emptyStatus;
nixnax 0:2cf4880c312a 168 }
nixnax 0:2cf4880c312a 169
nixnax 0:2cf4880c312a 170 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 171 {
nixnax 63:9253b0e1b7d8 172 __disable_irq(); // critical section start
nixnax 63:9253b0e1b7d8 173 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 63:9253b0e1b7d8 174 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 63:9253b0e1b7d8 175 __enable_irq(); // critical section end
nixnax 63:9253b0e1b7d8 176 return x;
nixnax 0:2cf4880c312a 177 }
nixnax 0:2cf4880c312a 178
nixnax 50:ad4e7c3c88e5 179 void processHDLCFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 180 {
nixnax 38:ab582987926e 181 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 182 if(start==end) {
nixnax 29:30de79d658f6 183 return;
nixnax 29:30de79d658f6 184 }
nixnax 9:0992486d4a30 185 crcReset();
nixnax 9:0992486d4a30 186 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 187 ppp.pkt.len=0;
nixnax 9:0992486d4a30 188 int unstuff=0;
nixnax 17:4918c893d802 189 int idx = start;
nixnax 17:4918c893d802 190 while(1) {
nixnax 9:0992486d4a30 191 if (unstuff==0) {
nixnax 72:ad3d12753acf 192 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 193 else {
nixnax 72:ad3d12753acf 194 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 195 ppp.pkt.len++;
nixnax 29:30de79d658f6 196 dest++;
nixnax 72:ad3d12753acf 197 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 198 }
nixnax 66:f005b9fdf4d1 199 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 200 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 201 ppp.pkt.len++;
nixnax 29:30de79d658f6 202 dest++;
nixnax 72:ad3d12753acf 203 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 204 unstuff=0;
nixnax 9:0992486d4a30 205 }
nixnax 17:4918c893d802 206 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 207 if (idx == end) break;
nixnax 9:0992486d4a30 208 }
nixnax 29:30de79d658f6 209 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 210 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 211 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 212 determinePacketType();
nixnax 29:30de79d658f6 213 } else if (v0) {
nixnax 66:f005b9fdf4d1 214 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 215 }
nixnax 9:0992486d4a30 216 }
nixnax 9:0992486d4a30 217
nixnax 38:ab582987926e 218 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 219 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 220 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 221 void dumpFrame()
nixnax 29:30de79d658f6 222 {
nixnax 42:4de44be70bfd 223 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 224 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 225 }
nixnax 16:cb0b80c24ba2 226
nixnax 29:30de79d658f6 227 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 228 {
nixnax 29:30de79d658f6 229 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 230 pc.putc(0x7d);
nixnax 66:f005b9fdf4d1 231 pc.putc(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 232 } else {
nixnax 29:30de79d658f6 233 pc.putc(ch);
nixnax 29:30de79d658f6 234 }
nixnax 11:f58998c24f0b 235 }
nixnax 9:0992486d4a30 236
nixnax 66:f005b9fdf4d1 237 void sendFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 238 {
nixnax 17:4918c893d802 239 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 240 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 241 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 242 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 243 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 244 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 245 }
nixnax 9:0992486d4a30 246
nixnax 66:f005b9fdf4d1 247 void ipConfigRequestHandler()
nixnax 29:30de79d658f6 248 {
nixnax 64:677b9713a120 249 debug("IPCP Conf ");
nixnax 9:0992486d4a30 250 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 66:f005b9fdf4d1 251 debug("Rej\n"); // reject any options that are requested
nixnax 9:0992486d4a30 252 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 253 sendFrame();
nixnax 9:0992486d4a30 254 } else {
nixnax 64:677b9713a120 255 debug("Ack\n");
nixnax 9:0992486d4a30 256 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 257 sendFrame(); // acknowledge
nixnax 64:677b9713a120 258 debug("IPCP Ask\n");
nixnax 9:0992486d4a30 259 // send our own request now
nixnax 12:db0dc91f0231 260 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 261 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 262 sendFrame(); // this is our request
nixnax 9:0992486d4a30 263 }
nixnax 9:0992486d4a30 264 }
nixnax 9:0992486d4a30 265
nixnax 29:30de79d658f6 266 void ipAckHandler()
nixnax 29:30de79d658f6 267 {
nixnax 64:677b9713a120 268 debug("IPCP Grant\n");
nixnax 29:30de79d658f6 269 }
nixnax 9:0992486d4a30 270
nixnax 29:30de79d658f6 271 void ipNackHandler()
nixnax 29:30de79d658f6 272 {
nixnax 64:677b9713a120 273 debug("IPCP Nack\n");
nixnax 29:30de79d658f6 274 }
nixnax 9:0992486d4a30 275
nixnax 29:30de79d658f6 276 void ipDefaultHandler()
nixnax 29:30de79d658f6 277 {
nixnax 64:677b9713a120 278 debug("IPCP Other\n");
nixnax 29:30de79d658f6 279 }
nixnax 29:30de79d658f6 280
nixnax 29:30de79d658f6 281 void IPCPframe()
nixnax 29:30de79d658f6 282 {
nixnax 9:0992486d4a30 283 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 284 switch (code) {
nixnax 29:30de79d658f6 285 case 1:
nixnax 66:f005b9fdf4d1 286 ipConfigRequestHandler();
nixnax 29:30de79d658f6 287 break;
nixnax 29:30de79d658f6 288 case 2:
nixnax 29:30de79d658f6 289 ipAckHandler();
nixnax 29:30de79d658f6 290 break;
nixnax 29:30de79d658f6 291 case 3:
nixnax 29:30de79d658f6 292 ipNackHandler();
nixnax 29:30de79d658f6 293 break;
nixnax 29:30de79d658f6 294 default:
nixnax 29:30de79d658f6 295 ipDefaultHandler();
nixnax 9:0992486d4a30 296 }
nixnax 29:30de79d658f6 297 }
nixnax 9:0992486d4a30 298
nixnax 29:30de79d658f6 299 void UDPpacket()
nixnax 29:30de79d658f6 300 {
nixnax 12:db0dc91f0231 301 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 302 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 303 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 63:9253b0e1b7d8 304 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 305 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 306 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 307 #endif
nixnax 12:db0dc91f0231 308 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 309 char * udpInf = udpBlock+8; // actual start of info
nixnax 63:9253b0e1b7d8 310 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 311 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 312 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 313 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 314 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 315 #endif
nixnax 29:30de79d658f6 316 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 317 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 42:4de44be70bfd 318 if(v1) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 42:4de44be70bfd 319 if(v1) debug("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort);
nixnax 42:4de44be70bfd 320 debug("Len %d ", udpLength);
nixnax 29:30de79d658f6 321 int printSize = udpLength;
nixnax 29:30de79d658f6 322 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 323 if (v0) {
nixnax 29:30de79d658f6 324 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 325 char ch = udpInf[i];
nixnax 29:30de79d658f6 326 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 327 debug("%c", ch);
nixnax 29:30de79d658f6 328 } else {
nixnax 64:677b9713a120 329 debug("_");
nixnax 29:30de79d658f6 330 }
nixnax 29:30de79d658f6 331 }
nixnax 64:677b9713a120 332 debug("\n");
nixnax 29:30de79d658f6 333 }
nixnax 12:db0dc91f0231 334 }
nixnax 11:f58998c24f0b 335
nixnax 29:30de79d658f6 336 int dataCheckSum(char * ptr, int len)
nixnax 29:30de79d658f6 337 {
nixnax 29:30de79d658f6 338 int sum=0;
nixnax 29:30de79d658f6 339 int placeHolder;
nixnax 29:30de79d658f6 340 if (len&1) {
nixnax 38:ab582987926e 341 placeHolder = ptr[len-1]; // when length is odd stuff in a zero byte
nixnax 29:30de79d658f6 342 ptr[len-1]=0;
nixnax 29:30de79d658f6 343 }
nixnax 29:30de79d658f6 344 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 345 int hi = *ptr;
nixnax 29:30de79d658f6 346 ptr++;
nixnax 29:30de79d658f6 347 int lo = *ptr;
nixnax 29:30de79d658f6 348 ptr++;
nixnax 11:f58998c24f0b 349 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 350 sum = sum + val;
nixnax 11:f58998c24f0b 351 }
nixnax 11:f58998c24f0b 352 sum = sum + (sum>>16);
nixnax 29:30de79d658f6 353 if (len&1) {
nixnax 29:30de79d658f6 354 ptr[len-1] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 355 }
nixnax 12:db0dc91f0231 356 return ~sum;
nixnax 29:30de79d658f6 357 }
nixnax 11:f58998c24f0b 358
nixnax 29:30de79d658f6 359 void headerCheckSum()
nixnax 29:30de79d658f6 360 {
nixnax 11:f58998c24f0b 361 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 362 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 363 int sum=0;
nixnax 11:f58998c24f0b 364
nixnax 29:30de79d658f6 365 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 366 int hi = *ptr;
nixnax 29:30de79d658f6 367 ptr++;
nixnax 29:30de79d658f6 368 int lo = *ptr;
nixnax 29:30de79d658f6 369 ptr++;
nixnax 11:f58998c24f0b 370 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 371 sum = sum + val;
nixnax 11:f58998c24f0b 372 }
nixnax 11:f58998c24f0b 373 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 374 sum = ~sum;
nixnax 11:f58998c24f0b 375 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 376 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 377 }
nixnax 9:0992486d4a30 378
nixnax 29:30de79d658f6 379 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 380 {
nixnax 12:db0dc91f0231 381 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 382 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 383 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 384 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 385 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 386 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 387 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 388 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 389 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 390 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 391 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 392 char * dstAdr = ipPkt+16;
nixnax 63:9253b0e1b7d8 393 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 394 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 395 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 63:9253b0e1b7d8 396 #endif
nixnax 42:4de44be70bfd 397 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 398 debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 399 char src[4];
nixnax 29:30de79d658f6 400 char dst[4];
nixnax 12:db0dc91f0231 401 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 402 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 403 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 404 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 405 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 406 chkSum[0]=0;
nixnax 29:30de79d658f6 407 chkSum[1]=0;
nixnax 12:db0dc91f0231 408 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 409 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 410 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 411 icmpSum[0]=0;
nixnax 29:30de79d658f6 412 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 413 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 16:cb0b80c24ba2 414 int sum = dataCheckSum( icmpType, icmpLength); // this checksum on icmp data portion
nixnax 29:30de79d658f6 415 icmpSum[0]=sum>>8;
nixnax 29:30de79d658f6 416 icmpSum[1]=sum; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 417
nixnax 16:cb0b80c24ba2 418 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 419 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 420 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 421 if (v0) {
nixnax 29:30de79d658f6 422 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 423 char ch = icmpData[i];
nixnax 29:30de79d658f6 424 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 425 debug("%c",ch);
nixnax 29:30de79d658f6 426 } else {
nixnax 64:677b9713a120 427 debug("_");
nixnax 29:30de79d658f6 428 }
nixnax 29:30de79d658f6 429 }
nixnax 64:677b9713a120 430 debug("\n");
nixnax 29:30de79d658f6 431 }
nixnax 15:b0154c910143 432 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 433
nixnax 12:db0dc91f0231 434 } else {
nixnax 29:30de79d658f6 435 if (v0) {
nixnax 42:4de44be70bfd 436 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 437 }
nixnax 11:f58998c24f0b 438 }
nixnax 11:f58998c24f0b 439 }
nixnax 11:f58998c24f0b 440
nixnax 29:30de79d658f6 441 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 442 {
nixnax 29:30de79d658f6 443 if (v0) {
nixnax 42:4de44be70bfd 444 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 445 }
nixnax 29:30de79d658f6 446 }
nixnax 11:f58998c24f0b 447
nixnax 29:30de79d658f6 448 void dumpHeaderIP ()
nixnax 29:30de79d658f6 449 {
nixnax 26:11f4eb2663a7 450 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 451 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 452 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 453 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 454 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 455 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 456 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 457 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 458 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 459 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 460 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 461 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 462 #endif
nixnax 26:11f4eb2663a7 463 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 464 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 465
nixnax 55:43faae812be3 466 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 467 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 468 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 469 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 470 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 471 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 472 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 473 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 474 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 475 int protocolIP = protocol[0];
nixnax 63:9253b0e1b7d8 476 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 477 #endif
nixnax 55:43faae812be3 478
nixnax 29:30de79d658f6 479 char srcIP [16];
nixnax 29:30de79d658f6 480 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 481 char dstIP [16];
nixnax 29:30de79d658f6 482 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 42:4de44be70bfd 483 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 484 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 485 }
nixnax 26:11f4eb2663a7 486
nixnax 29:30de79d658f6 487 void dumpHeaderTCP()
nixnax 29:30de79d658f6 488 {
nixnax 29:30de79d658f6 489 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 490 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 63:9253b0e1b7d8 491 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 492 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 493 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 63:9253b0e1b7d8 494 #endif
nixnax 29:30de79d658f6 495 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 63:9253b0e1b7d8 496 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 31:e000c1b9c565 497 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 498 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 63:9253b0e1b7d8 499 #endif
nixnax 26:11f4eb2663a7 500 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 501
nixnax 66:f005b9fdf4d1 502 char flagInfo[10]; // text string presentating the TCP flags
nixnax 66:f005b9fdf4d1 503 memset(flagInfo,'.', 9); // fill string with "........."
nixnax 70:713f86229288 504 memset(flagInfo+9,0,1); // null terminate string
nixnax 66:f005b9fdf4d1 505
nixnax 29:30de79d658f6 506 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 507 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 508 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 509 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 510 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 511 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 512 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 513 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 514 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 29:30de79d658f6 515 if (v0) {
nixnax 66:f005b9fdf4d1 516 debug("Flags %s Seq %u Ack %u", flagInfo, seq, ack); // show the flags in debug
nixnax 29:30de79d658f6 517 }
nixnax 29:30de79d658f6 518 }
nixnax 29:30de79d658f6 519
nixnax 68:0b74763ae67f 520 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 521 {
nixnax 67:a63e3486bcda 522 int n=0; // number of bytes we have printed so far
nixnax 67:a63e3486bcda 523 if(strncmp(dataStart, "GET / HTTP/1.1", 14) == 0 ) {
nixnax 67:a63e3486bcda 524 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 67:a63e3486bcda 525 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 67:a63e3486bcda 526 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 67:a63e3486bcda 527 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 67:a63e3486bcda 528 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 67:a63e3486bcda 529 int nHeader=n; // byte size of the HTTP header. Note - seems like this must be 1+(multiple of four)
nixnax 67:a63e3486bcda 530
nixnax 67:a63e3486bcda 531 // this is where we insert our web page into the buffer
nixnax 67:a63e3486bcda 532 n=n+sprintf(n+dataStart,"%s\r\n", ourWebPage);
nixnax 67:a63e3486bcda 533
nixnax 68:0b74763ae67f 534 #define CONTENTLENGTHSIZE 5
nixnax 67:a63e3486bcda 535 char contentLengthString[CONTENTLENGTHSIZE+1]; // temporary buffer to create Content-Length string
nixnax 68:0b74763ae67f 536 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 67:a63e3486bcda 537 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 538
nixnax 67:a63e3486bcda 539 if (v0) {
nixnax 67:a63e3486bcda 540 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 67:a63e3486bcda 541 }
nixnax 67:a63e3486bcda 542 } else { // all remaining requests get 404 Not Found response
nixnax 67:a63e3486bcda 543 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 67:a63e3486bcda 544 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 67:a63e3486bcda 545 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 67:a63e3486bcda 546 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 67:a63e3486bcda 547 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 67:a63e3486bcda 548 int nHeader=n; // byte total of all headers. Note - seems like this must be 1+(multiple of four)
nixnax 67:a63e3486bcda 549
nixnax 67:a63e3486bcda 550 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head></head>"); // html start
nixnax 67:a63e3486bcda 551 n=n+sprintf(n+dataStart,"<body><h1>File Not Found</h1></body>");
nixnax 67:a63e3486bcda 552 n=n+sprintf(n+dataStart,"</html>\r\n"); // html end
nixnax 67:a63e3486bcda 553
nixnax 68:0b74763ae67f 554 char contentLengthString[CONTENTLENGTHSIZE+1]; // temporary buffer to create Content-Length string
nixnax 68:0b74763ae67f 555 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 68:0b74763ae67f 556 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 557
nixnax 67:a63e3486bcda 558 if (v0) {
nixnax 67:a63e3486bcda 559 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 67:a63e3486bcda 560 }
nixnax 67:a63e3486bcda 561 }
nixnax 67:a63e3486bcda 562 return n; // total byte size of our response
nixnax 67:a63e3486bcda 563 }
nixnax 67:a63e3486bcda 564
nixnax 67:a63e3486bcda 565
nixnax 29:30de79d658f6 566 void tcpHandler()
nixnax 29:30de79d658f6 567 {
nixnax 26:11f4eb2663a7 568 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 569 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 570 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 571 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 572 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 573 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 574 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 575 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 576 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 577 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 578
nixnax 29:30de79d658f6 579 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 580 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 581
nixnax 29:30de79d658f6 582 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 583 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 584 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 585 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 586 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 587 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 588 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 589 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 590
nixnax 26:11f4eb2663a7 591 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 592 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 593 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 594
nixnax 31:e000c1b9c565 595 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 596 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 29:30de79d658f6 597
nixnax 35:e7068df4d971 598 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 599
nixnax 35:e7068df4d971 600 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 601 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 28:1aa629be05e7 602
nixnax 29:30de79d658f6 603 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 604 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 605 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 606 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 607 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 608
nixnax 35:e7068df4d971 609 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 610 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 611 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 612
nixnax 61:b3c1a04efd0a 613 ppp.seq = ack; // always adopt their sequence number calculation in place of doing our own calculation
nixnax 35:e7068df4d971 614
nixnax 69:23f560087c16 615 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 69:23f560087c16 616 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 69:23f560087c16 617 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 69:23f560087c16 618
nixnax 69:23f560087c16 619 switch ( flagsTCP ) {
nixnax 69:23f560087c16 620 case TCP_FLAG_ACK:
nixnax 69:23f560087c16 621 if ( tcpDataSize != 1 ) return;
nixnax 69:23f560087c16 622 case TCP_FLAG_SYN:
nixnax 69:23f560087c16 623 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - ack it
nixnax 69:23f560087c16 624 seq++; // for SYN flag we have to increase sequence by 1
nixnax 69:23f560087c16 625 break;
nixnax 69:23f560087c16 626 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 69:23f560087c16 627 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 69:23f560087c16 628 fastResponse = 1; // we can respond fast to a push
nixnax 69:23f560087c16 629 if ( strncmp(dataStart, "GET ", 4) == 0) { // do we see an http GET command
nixnax 69:23f560087c16 630 dataLen = httpResponse(dataStart); // send an http response
nixnax 69:23f560087c16 631 while((dataLen %4 ) !=0) { // dataLen must be a multiple of four
nixnax 69:23f560087c16 632 dataLen++; // must be a multiple of four
nixnax 69:23f560087c16 633 dataStart[dataLen-1]=0; // clear the byte in the buffer
nixnax 69:23f560087c16 634 }
nixnax 69:23f560087c16 635 }
nixnax 69:23f560087c16 636 break;
nixnax 69:23f560087c16 637 case TCP_FLAG_FIN:
nixnax 69:23f560087c16 638 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 69:23f560087c16 639 case TCP_FLAG_FIN | TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 69:23f560087c16 640 seq++; // for FIN flag we have to increase sequence by 1
nixnax 69:23f560087c16 641 break;
nixnax 69:23f560087c16 642 default:
nixnax 69:23f560087c16 643 return; // ignore remaining packets
nixnax 28:1aa629be05e7 644 }
nixnax 69:23f560087c16 645
nixnax 69:23f560087c16 646 // The TCP flag handling is now done
nixnax 38:ab582987926e 647 // 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 648
nixnax 65:23b17c43aa0f 649 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 650 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 651 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 652 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 653
nixnax 60:2b770949c911 654 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 655 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 656 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 29:30de79d658f6 657
nixnax 67:a63e3486bcda 658 ack = seq + tcpDataSize; // acknowledge the number of data bytes that they sent by adding it to "our" sequence number
nixnax 38:ab582987926e 659 seq = ppp.seq; // set up the sequence number we have to respond with
nixnax 38:ab582987926e 660
nixnax 38:ab582987926e 661 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 662 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 663 acktcp[2]=ack>>8;
nixnax 67:a63e3486bcda 664 acktcp[3]=ack>>0; // save ack 32-bit integer
nixnax 38:ab582987926e 665
nixnax 38:ab582987926e 666 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 667 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 668 seqtcp[2]=seq>>8;
nixnax 67:a63e3486bcda 669 seqtcp[3]=seq>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 670
nixnax 38:ab582987926e 671 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 672
nixnax 38:ab582987926e 673 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 674 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 675 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 676 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 677 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 678
nixnax 38:ab582987926e 679 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 680
nixnax 61:b3c1a04efd0a 681 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 682 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 683 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 684
nixnax 64:677b9713a120 685 // 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 686 // 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 687
nixnax 62:f192926e42f1 688 char * pseudoHeader = s-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 689 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 690 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 691 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 692 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 693 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 694 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 695
nixnax 61:b3c1a04efd0a 696 // pseudo-header built, now we can calculate TCP checksum
nixnax 63:9253b0e1b7d8 697
nixnax 29:30de79d658f6 698 checksumtcp[0]=0;
nixnax 29:30de79d658f6 699 checksumtcp[1]=0;
nixnax 62:f192926e42f1 700 int pseudoHeaderSum=dataCheckSum(pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 701 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 702 checksumtcp[1]=pseudoHeaderSum;
nixnax 61:b3c1a04efd0a 703 memcpy( s-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 60:2b770949c911 704
nixnax 36:2a9b457f8276 705 if (fastResponse==1) {
nixnax 36:2a9b457f8276 706 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 707 } else {
nixnax 68:0b74763ae67f 708 // normally, you wait 200 ms before sending a TCP packet
nixnax 68:0b74763ae67f 709 // remove the wait to respond faster
nixnax 68:0b74763ae67f 710 // wait(0.2);
nixnax 36:2a9b457f8276 711 }
nixnax 38:ab582987926e 712 sendFrame(); // All done! Send the TCP packet
nixnax 38:ab582987926e 713 ppp.seq = ppp.seq + dataLen; // increase OUR sequence by the outgoing data length - for the next round
nixnax 29:30de79d658f6 714 }
nixnax 26:11f4eb2663a7 715
nixnax 29:30de79d658f6 716 void dumpDataTCP()
nixnax 29:30de79d658f6 717 {
nixnax 26:11f4eb2663a7 718 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 719 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 720 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 721 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 722 if (v1) {
nixnax 42:4de44be70bfd 723 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 724 }
nixnax 29:30de79d658f6 725 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 726 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 727 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 728 }
nixnax 29:30de79d658f6 729 }
nixnax 26:11f4eb2663a7 730
nixnax 29:30de79d658f6 731 void TCPpacket()
nixnax 29:30de79d658f6 732 {
nixnax 26:11f4eb2663a7 733 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 734 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 735 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 736 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 737 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 738 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 739 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 740 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 741 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 742 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 743 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 744 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 745 #endif
nixnax 26:11f4eb2663a7 746 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 747 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 748
nixnax 55:43faae812be3 749 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 750 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 751 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 752 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 753 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 754 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 755 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 756 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 757 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 758 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 759 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 760 #endif
nixnax 29:30de79d658f6 761 char srcIP [16];
nixnax 29:30de79d658f6 762 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 763 char dstIP [16];
nixnax 29:30de79d658f6 764 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 765 if (v0) {
nixnax 42:4de44be70bfd 766 debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 29:30de79d658f6 767 }
nixnax 29:30de79d658f6 768 if (v0) {
nixnax 42:4de44be70bfd 769 debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 770 }
nixnax 28:1aa629be05e7 771 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 772 dumpDataTCP();
nixnax 26:11f4eb2663a7 773 tcpHandler();
nixnax 11:f58998c24f0b 774 }
nixnax 11:f58998c24f0b 775
nixnax 29:30de79d658f6 776 void otherProtocol()
nixnax 29:30de79d658f6 777 {
nixnax 64:677b9713a120 778 debug("Other IP protocol");
nixnax 29:30de79d658f6 779 }
nixnax 26:11f4eb2663a7 780
nixnax 29:30de79d658f6 781 void IPframe()
nixnax 29:30de79d658f6 782 {
nixnax 10:74f8233f72c0 783 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 784 switch (protocol) {
nixnax 29:30de79d658f6 785 case 1:
nixnax 29:30de79d658f6 786 ICMPpacket();
nixnax 29:30de79d658f6 787 break;
nixnax 29:30de79d658f6 788 case 2:
nixnax 29:30de79d658f6 789 IGMPpacket();
nixnax 29:30de79d658f6 790 break;
nixnax 29:30de79d658f6 791 case 17:
nixnax 29:30de79d658f6 792 UDPpacket();
nixnax 29:30de79d658f6 793 break;
nixnax 29:30de79d658f6 794 case 6:
nixnax 29:30de79d658f6 795 TCPpacket();
nixnax 29:30de79d658f6 796 break;
nixnax 29:30de79d658f6 797 default:
nixnax 29:30de79d658f6 798 otherProtocol();
nixnax 29:30de79d658f6 799 }
nixnax 29:30de79d658f6 800 }
nixnax 9:0992486d4a30 801
nixnax 29:30de79d658f6 802 void LCPconfReq()
nixnax 29:30de79d658f6 803 {
nixnax 64:677b9713a120 804 debug("LCP Config ");
nixnax 9:0992486d4a30 805 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 806 ppp.pkt.buf[4]=4; // allow only no options
nixnax 64:677b9713a120 807 debug("Reject\n");
nixnax 29:30de79d658f6 808 sendFrame();
nixnax 9:0992486d4a30 809 } else {
nixnax 9:0992486d4a30 810 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 64:677b9713a120 811 debug("Ack\n");
nixnax 9:0992486d4a30 812 sendFrame();
nixnax 64:677b9713a120 813 debug("LCP Ask\n");
nixnax 11:f58998c24f0b 814 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 815 sendFrame();
nixnax 9:0992486d4a30 816 }
nixnax 9:0992486d4a30 817 }
nixnax 9:0992486d4a30 818
nixnax 29:30de79d658f6 819 void LCPconfAck()
nixnax 29:30de79d658f6 820 {
nixnax 64:677b9713a120 821 debug("LCP Ack\n");
nixnax 29:30de79d658f6 822 }
nixnax 9:0992486d4a30 823
nixnax 29:30de79d658f6 824 void LCPend()
nixnax 29:30de79d658f6 825 {
nixnax 64:677b9713a120 826 debug("LCP End\n");
nixnax 29:30de79d658f6 827 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 828 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 829 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 830 }
nixnax 9:0992486d4a30 831
nixnax 29:30de79d658f6 832 void LCPother()
nixnax 29:30de79d658f6 833 {
nixnax 64:677b9713a120 834 debug("LCP Other\n");
nixnax 29:30de79d658f6 835 dumpFrame();
nixnax 29:30de79d658f6 836 }
nixnax 29:30de79d658f6 837
nixnax 29:30de79d658f6 838 void LCPframe()
nixnax 29:30de79d658f6 839 {
nixnax 29:30de79d658f6 840 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 841 switch (code) {
nixnax 29:30de79d658f6 842 case 1:
nixnax 29:30de79d658f6 843 LCPconfReq();
nixnax 29:30de79d658f6 844 break; // config request
nixnax 29:30de79d658f6 845 case 2:
nixnax 29:30de79d658f6 846 LCPconfAck();
nixnax 29:30de79d658f6 847 break; // config ack
nixnax 29:30de79d658f6 848 case 5:
nixnax 29:30de79d658f6 849 LCPend();
nixnax 29:30de79d658f6 850 break; // end connection
nixnax 29:30de79d658f6 851 default:
nixnax 29:30de79d658f6 852 LCPother();
nixnax 29:30de79d658f6 853 }
nixnax 9:0992486d4a30 854 }
nixnax 9:0992486d4a30 855
nixnax 29:30de79d658f6 856 void discardedFrame()
nixnax 29:30de79d658f6 857 {
nixnax 29:30de79d658f6 858 if (v0) {
nixnax 71:965619fedb3a 859 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 860 }
nixnax 9:0992486d4a30 861 }
nixnax 9:0992486d4a30 862
nixnax 29:30de79d658f6 863 void determinePacketType()
nixnax 29:30de79d658f6 864 {
nixnax 29:30de79d658f6 865 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 64:677b9713a120 866 debug("byte0 != ff\n");
nixnax 29:30de79d658f6 867 return;
nixnax 29:30de79d658f6 868 }
nixnax 29:30de79d658f6 869 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 64:677b9713a120 870 debug("byte1 != 3\n");
nixnax 29:30de79d658f6 871 return;
nixnax 29:30de79d658f6 872 }
nixnax 29:30de79d658f6 873 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 64:677b9713a120 874 debug("byte2 != 21\n");
nixnax 29:30de79d658f6 875 return;
nixnax 29:30de79d658f6 876 }
nixnax 9:0992486d4a30 877 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 878 switch (packetType) {
nixnax 29:30de79d658f6 879 case 0xc0:
nixnax 29:30de79d658f6 880 LCPframe();
nixnax 29:30de79d658f6 881 break; // link control
nixnax 29:30de79d658f6 882 case 0x80:
nixnax 29:30de79d658f6 883 IPCPframe();
nixnax 29:30de79d658f6 884 break; // IP control
nixnax 29:30de79d658f6 885 case 0x00:
nixnax 29:30de79d658f6 886 IPframe();
nixnax 29:30de79d658f6 887 break; // IP itself
nixnax 29:30de79d658f6 888 default:
nixnax 29:30de79d658f6 889 discardedFrame();
nixnax 9:0992486d4a30 890 }
nixnax 29:30de79d658f6 891 }
nixnax 9:0992486d4a30 892
nixnax 50:ad4e7c3c88e5 893 void wait_for_HDLC_frame()
nixnax 50:ad4e7c3c88e5 894 {
nixnax 50:ad4e7c3c88e5 895 while ( rxbufNotEmpty() ) {
nixnax 50:ad4e7c3c88e5 896 int rx = pc_getBuf();
nixnax 50:ad4e7c3c88e5 897 if (ppp.hdlc.frameBusy) {
nixnax 50:ad4e7c3c88e5 898 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 899 ppp.hdlc.frameBusy=0; // done gathering frame
nixnax 50:ad4e7c3c88e5 900 if (ppp.rx.tail == 0) { // did we just wrap around?
nixnax 50:ad4e7c3c88e5 901 ppp.hdlc.frameEndIndex=BUFLEN-1; // wrap back to end of buffer
nixnax 51:a86d56844324 902 } else {
nixnax 50:ad4e7c3c88e5 903 ppp.hdlc.frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 50:ad4e7c3c88e5 904 }
nixnax 50:ad4e7c3c88e5 905 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex);
nixnax 72:ad3d12753acf 906 ppp.hdlc.frameStartIndex = ppp.hdlc.frameEndIndex;
nixnax 50:ad4e7c3c88e5 907 }
nixnax 50:ad4e7c3c88e5 908 } else {
nixnax 50:ad4e7c3c88e5 909 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 910 ppp.hdlc.frameBusy=1; // start gathering frame
nixnax 50:ad4e7c3c88e5 911 ppp.hdlc.frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 50:ad4e7c3c88e5 912 }
nixnax 50:ad4e7c3c88e5 913 }
nixnax 50:ad4e7c3c88e5 914 }
nixnax 50:ad4e7c3c88e5 915 }
nixnax 50:ad4e7c3c88e5 916
nixnax 29:30de79d658f6 917 void scanForConnectString()
nixnax 29:30de79d658f6 918 {
nixnax 9:0992486d4a30 919 if ( ppp.online==0 ) {
nixnax 71:965619fedb3a 920 // look for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 72:ad3d12753acf 921 char * clientFound = strstr( (char *)ppp.rx.buf, "CLIENTCLIENT" );
nixnax 29:30de79d658f6 922 if( clientFound ) {
nixnax 57:8deab70fef2e 923 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't find it again
nixnax 71:965619fedb3a 924 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 71:965619fedb3a 925 pc.printf("CLIENTSERVER");
nixnax 71:965619fedb3a 926 ppp.online=1; // we are connected, so stop looking for the string
nixnax 64:677b9713a120 927 debug("Connect string found\n");
nixnax 9:0992486d4a30 928 }
nixnax 9:0992486d4a30 929 }
nixnax 9:0992486d4a30 930 }
nixnax 9:0992486d4a30 931
nixnax 0:2cf4880c312a 932 int main()
nixnax 0:2cf4880c312a 933 {
nixnax 14:c65831c25aaa 934 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 935 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 49:2213f9c132b2 936 xx.baud(115200); // second serial port for debug messages
nixnax 9:0992486d4a30 937 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 938 #endif
nixnax 9:0992486d4a30 939 pppInitStruct(); // initialize all the PPP properties
nixnax 9:0992486d4a30 940 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 0:2cf4880c312a 941 while(1) {
nixnax 51:a86d56844324 942 scanForConnectString(); // respond to connect command from windows dial up networking
nixnax 50:ad4e7c3c88e5 943 wait_for_HDLC_frame();
nixnax 7:ab147f5e97ac 944 }
nixnax 7:ab147f5e97ac 945 }