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@71:965619fedb3a, 2017-06-08 (annotated)

Committer:
nixnax
Date:
Thu Jun 08 15:45:40 2017 +0000
Revision:
71:965619fedb3a
Parent:
70:713f86229288
Child:
72:ad3d12753acf
Debug/Comments

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 0:2cf4880c312a 1 #include "mbed.h"
nixnax 0:2cf4880c312a 2
nixnax 29:30de79d658f6 3 // Copyright 2016 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax 12:db0dc91f0231 4
nixnax 41:e58a5a09f411 5 // PPP-Blinky - "My Internet Of Thing"
nixnax 41:e58a5a09f411 6 // A Tiny Webserver Using Windows XP/7/8/10 Networking Over A Serial Port.
nixnax 0:2cf4880c312a 7
nixnax 41:e58a5a09f411 8 // Also receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 4:a469050d5b80 9
nixnax 41:e58a5a09f411 10 // Notes and Instructions
nixnax 41:e58a5a09f411 11 // http://bit.ly/PPP-Blinky-Instructions
nixnax 0:2cf4880c312a 12
nixnax 41:e58a5a09f411 13 // Handy reading material
nixnax 6:fba4c2e817b8 14 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 15 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 39:b90183d35f1e 16 // http://bit.ly/dialup777error - how to solve Dial Up Error 777 in Windows 7/8/10
nixnax 41:e58a5a09f411 17 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 18
nixnax 29:30de79d658f6 19 // Handy tools
nixnax 44:d0c61ae49ea5 20 // https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax 44:d0c61ae49ea5 21 // Wireshark - can't monitor Dial-Up network packets on windows, but useful - can import our dumpFrame routine's hex output
nixnax 29:30de79d658f6 22 // Microsoft network monitor - real-time monitoring of all our packets
nixnax 29:30de79d658f6 23 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 29:30de79d658f6 24 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE)
nixnax 41:e58a5a09f411 25 // The curl.exe program in Windows Powershell - use it like this to stress test the webserver: while (1) { curl 172.10.10.1 }
nixnax 29:30de79d658f6 26 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 41:e58a5a09f411 27 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 41:e58a5a09f411 28
nixnax 66:f005b9fdf4d1 29
nixnax 66:f005b9fdf4d1 30 // The #define below enables/disables a SECOND (optional) serial port that prints out interesting diagnostic messages.
nixnax 66:f005b9fdf4d1 31 // Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor this.
nixnax 48:6352c1411c5f 32 #define SERIAL_PORT_MONITOR_NO /* or SERIAL_PORT_MONITOR_YES */
nixnax 0:2cf4880c312a 33
nixnax 41:e58a5a09f411 34 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 66:f005b9fdf4d1 35 Serial xx(PC_10, PC_11); // Not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax 42:4de44be70bfd 36 #define debug(x...) xx.printf (x)
nixnax 41:e58a5a09f411 37 #else
nixnax 42:4de44be70bfd 38 #define debug(x...) {}
nixnax 41:e58a5a09f411 39 #endif
nixnax 41:e58a5a09f411 40
nixnax 66:f005b9fdf4d1 41 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 66:f005b9fdf4d1 42 #define v0 1
nixnax 66:f005b9fdf4d1 43 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 66:f005b9fdf4d1 44 #define v1 1
nixnax 29:30de79d658f6 45
nixnax 66:f005b9fdf4d1 46 // this is the webpage we serve when we get an HTTP request
nixnax 66:f005b9fdf4d1 47 // keep size under 900 bytes to fit in a single frame
nixnax 66:f005b9fdf4d1 48 const static char ourWebPage[] = "\
nixnax 66:f005b9fdf4d1 49 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 50 <html>\
nixnax 66:f005b9fdf4d1 51 <head>\
nixnax 66:f005b9fdf4d1 52 <title>mbed-PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 53 <script>\
nixnax 66:f005b9fdf4d1 54 window.onload=function(){\
nixnax 66:f005b9fdf4d1 55 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 66:f005b9fdf4d1 56 x().textContent = parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 57 </script>\
nixnax 66:f005b9fdf4d1 58 </head>\
nixnax 66:f005b9fdf4d1 59 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 60 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 61 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 62 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 63 </body>\
nixnax 69:23f560087c16 64 </html>"; // around 464 bytes long
nixnax 69:23f560087c16 65
nixnax 69:23f560087c16 66
nixnax 66:f005b9fdf4d1 67
nixnax 66:f005b9fdf4d1 68 // The serial port on your mbed hardware. Your PC should view this as a standard dial-up networking modem. See instructions at the top.
nixnax 66:f005b9fdf4d1 69 // On a typical mbed hardware platform this is a USB virtual com port (VCP)
nixnax 66:f005b9fdf4d1 70 Serial pc(USBTX, USBRX); // usb virtual com port
nixnax 29:30de79d658f6 71
nixnax 29:30de79d658f6 72 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 73
nixnax 66:f005b9fdf4d1 74 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 75 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 76
nixnax 29:30de79d658f6 77 // the serial port receive buffer and packet buffer
nixnax 69:23f560087c16 78 #define BUFLEN (1<<13)
nixnax 66:f005b9fdf4d1 79 char rxbufppp[BUFLEN]; // BUFLEN MUST be a power of two because we use & operator for fast wrap-around in rxHandler
nixnax 69:23f560087c16 80 char hdlcBuffer[3000]; // send and receive buffer for unstuffed (decoded) hdlc frames
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 20:5db9b77b38a6 90 char * buf;
nixnax 29:30de79d658f6 91 volatile int head;
nixnax 29:30de79d658f6 92 volatile int tail;
nixnax 38:ab582987926e 93 } rx; // serial port objects
nixnax 4:a469050d5b80 94 struct {
nixnax 38:ab582987926e 95 int len; // number of bytes in buffer
nixnax 38:ab582987926e 96 int crc; // PPP CRC (frame check)
nixnax 38:ab582987926e 97 char * buf; // the actual buffer
nixnax 38:ab582987926e 98 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 99 struct {
nixnax 50:ad4e7c3c88e5 100 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 101 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 102 int frameBusy; // busy capturing a frame
nixnax 50:ad4e7c3c88e5 103 } hdlc; // hdlc frame objects
nixnax 29:30de79d658f6 104 };
nixnax 31:e000c1b9c565 105
nixnax 29:30de79d658f6 106 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 107
nixnax 60:2b770949c911 108 // Initialize our globals
nixnax 29:30de79d658f6 109 void pppInitStruct()
nixnax 29:30de79d658f6 110 {
nixnax 29:30de79d658f6 111 ppp.online=0;
nixnax 49:2213f9c132b2 112 ppp.rx.buf=rxbufppp;
nixnax 29:30de79d658f6 113 ppp.rx.tail=0;
nixnax 29:30de79d658f6 114 ppp.rx.head=0;
nixnax 52:accc3026b2b0 115 ppp.pkt.buf=hdlcBuffer;
nixnax 29:30de79d658f6 116 ppp.pkt.len=0;
nixnax 29:30de79d658f6 117 ppp.ident=0;
nixnax 35:e7068df4d971 118 ppp.seq=1000;
nixnax 29:30de79d658f6 119 ppp.ledState=0;
nixnax 50:ad4e7c3c88e5 120 ppp.hdlc.frameBusy=0;
nixnax 29:30de79d658f6 121 }
nixnax 26:11f4eb2663a7 122
nixnax 43:aa57db08995d 123 void led1Toggle()
nixnax 43:aa57db08995d 124 {
nixnax 43:aa57db08995d 125 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 126 led1 = ppp.ledState;
nixnax 43:aa57db08995d 127 }
nixnax 43:aa57db08995d 128
nixnax 29:30de79d658f6 129 void crcReset()
nixnax 29:30de79d658f6 130 {
nixnax 29:30de79d658f6 131 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 132 }
nixnax 4:a469050d5b80 133
nixnax 29:30de79d658f6 134 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 135 {
nixnax 29:30de79d658f6 136 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 137 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 138 x>>=1;
nixnax 29:30de79d658f6 139 }
nixnax 29:30de79d658f6 140 }
nixnax 29:30de79d658f6 141
nixnax 29:30de79d658f6 142 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 143 {
nixnax 31:e000c1b9c565 144 crcReset();
nixnax 31:e000c1b9c565 145 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 146 return ppp.crc;
nixnax 29:30de79d658f6 147 }
nixnax 0:2cf4880c312a 148
nixnax 0:2cf4880c312a 149 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 150 {
nixnax 17:4918c893d802 151 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 152 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 153 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 154 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 155 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 156 }
nixnax 0:2cf4880c312a 157 }
nixnax 0:2cf4880c312a 158
nixnax 22:00df34cd4d7e 159 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 160 {
nixnax 22:00df34cd4d7e 161 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 162 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 163 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 164 return emptyStatus;
nixnax 0:2cf4880c312a 165 }
nixnax 0:2cf4880c312a 166
nixnax 0:2cf4880c312a 167 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 168 {
nixnax 63:9253b0e1b7d8 169 __disable_irq(); // critical section start
nixnax 63:9253b0e1b7d8 170 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 63:9253b0e1b7d8 171 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 63:9253b0e1b7d8 172 __enable_irq(); // critical section end
nixnax 63:9253b0e1b7d8 173 return x;
nixnax 0:2cf4880c312a 174 }
nixnax 0:2cf4880c312a 175
nixnax 50:ad4e7c3c88e5 176 void processHDLCFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 177 {
nixnax 38:ab582987926e 178 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 179 if(start==end) {
nixnax 29:30de79d658f6 180 pc.putc(0x7e);
nixnax 29:30de79d658f6 181 return;
nixnax 29:30de79d658f6 182 }
nixnax 9:0992486d4a30 183 crcReset();
nixnax 9:0992486d4a30 184 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 185 ppp.pkt.len=0;
nixnax 9:0992486d4a30 186 int unstuff=0;
nixnax 17:4918c893d802 187 int idx = start;
nixnax 17:4918c893d802 188 while(1) {
nixnax 9:0992486d4a30 189 if (unstuff==0) {
nixnax 49:2213f9c132b2 190 if (rxbufppp[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 191 else {
nixnax 49:2213f9c132b2 192 *dest = rxbufppp[idx];
nixnax 29:30de79d658f6 193 ppp.pkt.len++;
nixnax 29:30de79d658f6 194 dest++;
nixnax 49:2213f9c132b2 195 crcDo(rxbufppp[idx]);
nixnax 29:30de79d658f6 196 }
nixnax 66:f005b9fdf4d1 197 } else { // unstuff characters prefixed with 0x7d
nixnax 49:2213f9c132b2 198 *dest = rxbufppp[idx]^0x20;
nixnax 29:30de79d658f6 199 ppp.pkt.len++;
nixnax 29:30de79d658f6 200 dest++;
nixnax 49:2213f9c132b2 201 crcDo(rxbufppp[idx]^0x20);
nixnax 9:0992486d4a30 202 unstuff=0;
nixnax 9:0992486d4a30 203 }
nixnax 17:4918c893d802 204 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 205 if (idx == end) break;
nixnax 9:0992486d4a30 206 }
nixnax 29:30de79d658f6 207 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 208 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 209 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 210 determinePacketType();
nixnax 29:30de79d658f6 211 } else if (v0) {
nixnax 66:f005b9fdf4d1 212 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 213 }
nixnax 9:0992486d4a30 214 }
nixnax 9:0992486d4a30 215
nixnax 38:ab582987926e 216 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 217 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 218 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 219 void dumpFrame()
nixnax 29:30de79d658f6 220 {
nixnax 42:4de44be70bfd 221 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 222 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 223 }
nixnax 16:cb0b80c24ba2 224
nixnax 29:30de79d658f6 225 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 226 {
nixnax 29:30de79d658f6 227 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 228 pc.putc(0x7d);
nixnax 66:f005b9fdf4d1 229 pc.putc(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 230 } else {
nixnax 29:30de79d658f6 231 pc.putc(ch);
nixnax 29:30de79d658f6 232 }
nixnax 11:f58998c24f0b 233 }
nixnax 9:0992486d4a30 234
nixnax 66:f005b9fdf4d1 235 void sendFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 236 {
nixnax 17:4918c893d802 237 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 238 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 239 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 240 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 241 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 242 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 243 }
nixnax 9:0992486d4a30 244
nixnax 66:f005b9fdf4d1 245 void ipConfigRequestHandler()
nixnax 29:30de79d658f6 246 {
nixnax 64:677b9713a120 247 debug("IPCP Conf ");
nixnax 9:0992486d4a30 248 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 66:f005b9fdf4d1 249 debug("Rej\n"); // reject any options that are requested
nixnax 9:0992486d4a30 250 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 251 sendFrame();
nixnax 9:0992486d4a30 252 } else {
nixnax 64:677b9713a120 253 debug("Ack\n");
nixnax 9:0992486d4a30 254 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 255 sendFrame(); // acknowledge
nixnax 64:677b9713a120 256 debug("IPCP Ask\n");
nixnax 9:0992486d4a30 257 // send our own request now
nixnax 12:db0dc91f0231 258 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 259 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 260 sendFrame(); // this is our request
nixnax 9:0992486d4a30 261 }
nixnax 9:0992486d4a30 262 }
nixnax 9:0992486d4a30 263
nixnax 29:30de79d658f6 264 void ipAckHandler()
nixnax 29:30de79d658f6 265 {
nixnax 64:677b9713a120 266 debug("IPCP Grant\n");
nixnax 29:30de79d658f6 267 }
nixnax 9:0992486d4a30 268
nixnax 29:30de79d658f6 269 void ipNackHandler()
nixnax 29:30de79d658f6 270 {
nixnax 64:677b9713a120 271 debug("IPCP Nack\n");
nixnax 29:30de79d658f6 272 }
nixnax 9:0992486d4a30 273
nixnax 29:30de79d658f6 274 void ipDefaultHandler()
nixnax 29:30de79d658f6 275 {
nixnax 64:677b9713a120 276 debug("IPCP Other\n");
nixnax 29:30de79d658f6 277 }
nixnax 29:30de79d658f6 278
nixnax 29:30de79d658f6 279 void IPCPframe()
nixnax 29:30de79d658f6 280 {
nixnax 9:0992486d4a30 281 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 282 switch (code) {
nixnax 29:30de79d658f6 283 case 1:
nixnax 66:f005b9fdf4d1 284 ipConfigRequestHandler();
nixnax 29:30de79d658f6 285 break;
nixnax 29:30de79d658f6 286 case 2:
nixnax 29:30de79d658f6 287 ipAckHandler();
nixnax 29:30de79d658f6 288 break;
nixnax 29:30de79d658f6 289 case 3:
nixnax 29:30de79d658f6 290 ipNackHandler();
nixnax 29:30de79d658f6 291 break;
nixnax 29:30de79d658f6 292 default:
nixnax 29:30de79d658f6 293 ipDefaultHandler();
nixnax 9:0992486d4a30 294 }
nixnax 29:30de79d658f6 295 }
nixnax 9:0992486d4a30 296
nixnax 29:30de79d658f6 297 void UDPpacket()
nixnax 29:30de79d658f6 298 {
nixnax 12:db0dc91f0231 299 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 300 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 301 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 63:9253b0e1b7d8 302 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 303 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 304 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 305 #endif
nixnax 12:db0dc91f0231 306 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 307 char * udpInf = udpBlock+8; // actual start of info
nixnax 63:9253b0e1b7d8 308 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 309 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 310 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 311 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 312 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 313 #endif
nixnax 29:30de79d658f6 314 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 315 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 42:4de44be70bfd 316 if(v1) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 42:4de44be70bfd 317 if(v1) debug("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort);
nixnax 42:4de44be70bfd 318 debug("Len %d ", udpLength);
nixnax 29:30de79d658f6 319 int printSize = udpLength;
nixnax 29:30de79d658f6 320 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 321 if (v0) {
nixnax 29:30de79d658f6 322 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 323 char ch = udpInf[i];
nixnax 29:30de79d658f6 324 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 325 debug("%c", ch);
nixnax 29:30de79d658f6 326 } else {
nixnax 64:677b9713a120 327 debug("_");
nixnax 29:30de79d658f6 328 }
nixnax 29:30de79d658f6 329 }
nixnax 64:677b9713a120 330 debug("\n");
nixnax 29:30de79d658f6 331 }
nixnax 12:db0dc91f0231 332 }
nixnax 11:f58998c24f0b 333
nixnax 29:30de79d658f6 334 int dataCheckSum(char * ptr, int len)
nixnax 29:30de79d658f6 335 {
nixnax 29:30de79d658f6 336 int sum=0;
nixnax 29:30de79d658f6 337 int placeHolder;
nixnax 29:30de79d658f6 338 if (len&1) {
nixnax 38:ab582987926e 339 placeHolder = ptr[len-1]; // when length is odd stuff in a zero byte
nixnax 29:30de79d658f6 340 ptr[len-1]=0;
nixnax 29:30de79d658f6 341 }
nixnax 29:30de79d658f6 342 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 343 int hi = *ptr;
nixnax 29:30de79d658f6 344 ptr++;
nixnax 29:30de79d658f6 345 int lo = *ptr;
nixnax 29:30de79d658f6 346 ptr++;
nixnax 11:f58998c24f0b 347 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 348 sum = sum + val;
nixnax 11:f58998c24f0b 349 }
nixnax 11:f58998c24f0b 350 sum = sum + (sum>>16);
nixnax 29:30de79d658f6 351 if (len&1) {
nixnax 29:30de79d658f6 352 ptr[len-1] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 353 }
nixnax 12:db0dc91f0231 354 return ~sum;
nixnax 29:30de79d658f6 355 }
nixnax 11:f58998c24f0b 356
nixnax 29:30de79d658f6 357 void headerCheckSum()
nixnax 29:30de79d658f6 358 {
nixnax 11:f58998c24f0b 359 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 360 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 361 int sum=0;
nixnax 11:f58998c24f0b 362
nixnax 29:30de79d658f6 363 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 364 int hi = *ptr;
nixnax 29:30de79d658f6 365 ptr++;
nixnax 29:30de79d658f6 366 int lo = *ptr;
nixnax 29:30de79d658f6 367 ptr++;
nixnax 11:f58998c24f0b 368 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 369 sum = sum + val;
nixnax 11:f58998c24f0b 370 }
nixnax 11:f58998c24f0b 371 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 372 sum = ~sum;
nixnax 11:f58998c24f0b 373 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 374 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 375 }
nixnax 9:0992486d4a30 376
nixnax 29:30de79d658f6 377 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 378 {
nixnax 12:db0dc91f0231 379 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 380 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 381 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 382 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 383 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 384 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 385 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 386 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 387 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 388 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 389 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 390 char * dstAdr = ipPkt+16;
nixnax 63:9253b0e1b7d8 391 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 392 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 393 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 63:9253b0e1b7d8 394 #endif
nixnax 42:4de44be70bfd 395 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 396 debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 397 char src[4];
nixnax 29:30de79d658f6 398 char dst[4];
nixnax 12:db0dc91f0231 399 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 400 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 401 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 402 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 403 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 404 chkSum[0]=0;
nixnax 29:30de79d658f6 405 chkSum[1]=0;
nixnax 12:db0dc91f0231 406 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 407 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 408 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 409 icmpSum[0]=0;
nixnax 29:30de79d658f6 410 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 411 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 16:cb0b80c24ba2 412 int sum = dataCheckSum( icmpType, icmpLength); // this checksum on icmp data portion
nixnax 29:30de79d658f6 413 icmpSum[0]=sum>>8;
nixnax 29:30de79d658f6 414 icmpSum[1]=sum; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 415
nixnax 16:cb0b80c24ba2 416 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 417 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 418 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 419 if (v0) {
nixnax 29:30de79d658f6 420 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 421 char ch = icmpData[i];
nixnax 29:30de79d658f6 422 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 423 debug("%c",ch);
nixnax 29:30de79d658f6 424 } else {
nixnax 64:677b9713a120 425 debug("_");
nixnax 29:30de79d658f6 426 }
nixnax 29:30de79d658f6 427 }
nixnax 64:677b9713a120 428 debug("\n");
nixnax 29:30de79d658f6 429 }
nixnax 15:b0154c910143 430 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 431
nixnax 12:db0dc91f0231 432 } else {
nixnax 29:30de79d658f6 433 if (v0) {
nixnax 42:4de44be70bfd 434 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 435 }
nixnax 11:f58998c24f0b 436 }
nixnax 11:f58998c24f0b 437 }
nixnax 11:f58998c24f0b 438
nixnax 29:30de79d658f6 439 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 440 {
nixnax 29:30de79d658f6 441 if (v0) {
nixnax 42:4de44be70bfd 442 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 443 }
nixnax 29:30de79d658f6 444 }
nixnax 11:f58998c24f0b 445
nixnax 29:30de79d658f6 446 void dumpHeaderIP ()
nixnax 29:30de79d658f6 447 {
nixnax 26:11f4eb2663a7 448 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 449 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 450 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 451 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 452 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 453 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 454 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 455 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 456 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 457 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 458 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 459 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 460 #endif
nixnax 26:11f4eb2663a7 461 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 462 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 463
nixnax 55:43faae812be3 464 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 465 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 466 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 467 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 468 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 469 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 470 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 471 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 472 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 473 int protocolIP = protocol[0];
nixnax 63:9253b0e1b7d8 474 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 475 #endif
nixnax 55:43faae812be3 476
nixnax 29:30de79d658f6 477 char srcIP [16];
nixnax 29:30de79d658f6 478 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 479 char dstIP [16];
nixnax 29:30de79d658f6 480 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 42:4de44be70bfd 481 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 482 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 483 }
nixnax 26:11f4eb2663a7 484
nixnax 29:30de79d658f6 485 void dumpHeaderTCP()
nixnax 29:30de79d658f6 486 {
nixnax 29:30de79d658f6 487 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 488 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 63:9253b0e1b7d8 489 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 490 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 491 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 63:9253b0e1b7d8 492 #endif
nixnax 29:30de79d658f6 493 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 63:9253b0e1b7d8 494 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 31:e000c1b9c565 495 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 496 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 63:9253b0e1b7d8 497 #endif
nixnax 26:11f4eb2663a7 498 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 499
nixnax 66:f005b9fdf4d1 500 char flagInfo[10]; // text string presentating the TCP flags
nixnax 66:f005b9fdf4d1 501 memset(flagInfo,'.', 9); // fill string with "........."
nixnax 70:713f86229288 502 memset(flagInfo+9,0,1); // null terminate string
nixnax 66:f005b9fdf4d1 503
nixnax 29:30de79d658f6 504 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 505 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 506 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 507 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 508 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 509 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 510 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 511 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 512 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 29:30de79d658f6 513 if (v0) {
nixnax 66:f005b9fdf4d1 514 debug("Flags %s Seq %u Ack %u", flagInfo, seq, ack); // show the flags in debug
nixnax 29:30de79d658f6 515 }
nixnax 29:30de79d658f6 516 }
nixnax 29:30de79d658f6 517
nixnax 68:0b74763ae67f 518 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 519 {
nixnax 67:a63e3486bcda 520 int n=0; // number of bytes we have printed so far
nixnax 67:a63e3486bcda 521 if(strncmp(dataStart, "GET / HTTP/1.1", 14) == 0 ) {
nixnax 67:a63e3486bcda 522 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 67:a63e3486bcda 523 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 67:a63e3486bcda 524 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 67:a63e3486bcda 525 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 67:a63e3486bcda 526 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 527 int nHeader=n; // byte size of the HTTP header. Note - seems like this must be 1+(multiple of four)
nixnax 67:a63e3486bcda 528
nixnax 67:a63e3486bcda 529 // this is where we insert our web page into the buffer
nixnax 67:a63e3486bcda 530 n=n+sprintf(n+dataStart,"%s\r\n", ourWebPage);
nixnax 67:a63e3486bcda 531
nixnax 68:0b74763ae67f 532 #define CONTENTLENGTHSIZE 5
nixnax 67:a63e3486bcda 533 char contentLengthString[CONTENTLENGTHSIZE+1]; // temporary buffer to create Content-Length string
nixnax 68:0b74763ae67f 534 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 67:a63e3486bcda 535 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 536
nixnax 67:a63e3486bcda 537 if (v0) {
nixnax 67:a63e3486bcda 538 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 539 }
nixnax 67:a63e3486bcda 540 } else { // all remaining requests get 404 Not Found response
nixnax 67:a63e3486bcda 541 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 67:a63e3486bcda 542 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 67:a63e3486bcda 543 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 67:a63e3486bcda 544 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 67:a63e3486bcda 545 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 546 int nHeader=n; // byte total of all headers. Note - seems like this must be 1+(multiple of four)
nixnax 67:a63e3486bcda 547
nixnax 67:a63e3486bcda 548 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head></head>"); // html start
nixnax 67:a63e3486bcda 549 n=n+sprintf(n+dataStart,"<body><h1>File Not Found</h1></body>");
nixnax 67:a63e3486bcda 550 n=n+sprintf(n+dataStart,"</html>\r\n"); // html end
nixnax 67:a63e3486bcda 551
nixnax 68:0b74763ae67f 552 char contentLengthString[CONTENTLENGTHSIZE+1]; // temporary buffer to create Content-Length string
nixnax 68:0b74763ae67f 553 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 68:0b74763ae67f 554 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 555
nixnax 67:a63e3486bcda 556 if (v0) {
nixnax 67:a63e3486bcda 557 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 558 }
nixnax 67:a63e3486bcda 559 }
nixnax 67:a63e3486bcda 560 return n; // total byte size of our response
nixnax 67:a63e3486bcda 561 }
nixnax 67:a63e3486bcda 562
nixnax 67:a63e3486bcda 563
nixnax 29:30de79d658f6 564 void tcpHandler()
nixnax 29:30de79d658f6 565 {
nixnax 26:11f4eb2663a7 566 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 567 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 568 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 569 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 570 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 571 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 572 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 573 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 574 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 575 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 576
nixnax 29:30de79d658f6 577 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 578 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 579
nixnax 29:30de79d658f6 580 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 581 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 582 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 583 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 584 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 585 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 586 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 587 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 588
nixnax 26:11f4eb2663a7 589 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 590 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 591 int protocolIP = protocol[0];
nixnax 29:30de79d658f6 592
nixnax 31:e000c1b9c565 593 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 594 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 29:30de79d658f6 595
nixnax 35:e7068df4d971 596 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 597
nixnax 35:e7068df4d971 598 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 67:a63e3486bcda 599 int tcpDataSize = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 28:1aa629be05e7 600
nixnax 29:30de79d658f6 601 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 602 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 603 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 604 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 605 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 606
nixnax 35:e7068df4d971 607 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 608 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 609 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 610
nixnax 61:b3c1a04efd0a 611 ppp.seq = ack; // always adopt their sequence number calculation in place of doing our own calculation
nixnax 35:e7068df4d971 612
nixnax 69:23f560087c16 613 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 69:23f560087c16 614 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 69:23f560087c16 615 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 69:23f560087c16 616
nixnax 69:23f560087c16 617 switch ( flagsTCP ) {
nixnax 69:23f560087c16 618 case TCP_FLAG_ACK:
nixnax 69:23f560087c16 619 if ( tcpDataSize != 1 ) return;
nixnax 69:23f560087c16 620 case TCP_FLAG_SYN:
nixnax 69:23f560087c16 621 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - ack it
nixnax 69:23f560087c16 622 seq++; // for SYN flag we have to increase sequence by 1
nixnax 69:23f560087c16 623 break;
nixnax 69:23f560087c16 624 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 69:23f560087c16 625 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 69:23f560087c16 626 fastResponse = 1; // we can respond fast to a push
nixnax 69:23f560087c16 627 if ( strncmp(dataStart, "GET ", 4) == 0) { // do we see an http GET command
nixnax 69:23f560087c16 628 dataLen = httpResponse(dataStart); // send an http response
nixnax 69:23f560087c16 629 while((dataLen %4 ) !=0) { // dataLen must be a multiple of four
nixnax 69:23f560087c16 630 dataLen++; // must be a multiple of four
nixnax 69:23f560087c16 631 dataStart[dataLen-1]=0; // clear the byte in the buffer
nixnax 69:23f560087c16 632 }
nixnax 69:23f560087c16 633 }
nixnax 69:23f560087c16 634 break;
nixnax 69:23f560087c16 635 case TCP_FLAG_FIN:
nixnax 69:23f560087c16 636 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 69:23f560087c16 637 case TCP_FLAG_FIN | TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 69:23f560087c16 638 seq++; // for FIN flag we have to increase sequence by 1
nixnax 69:23f560087c16 639 break;
nixnax 69:23f560087c16 640 default:
nixnax 69:23f560087c16 641 return; // ignore remaining packets
nixnax 28:1aa629be05e7 642 }
nixnax 69:23f560087c16 643
nixnax 69:23f560087c16 644 // The TCP flag handling is now done
nixnax 38:ab582987926e 645 // 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 646
nixnax 65:23b17c43aa0f 647 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 648 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 649 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 650 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 651
nixnax 60:2b770949c911 652 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 653 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 654 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 29:30de79d658f6 655
nixnax 67:a63e3486bcda 656 ack = seq + tcpDataSize; // acknowledge the number of data bytes that they sent by adding it to "our" sequence number
nixnax 38:ab582987926e 657 seq = ppp.seq; // set up the sequence number we have to respond with
nixnax 38:ab582987926e 658
nixnax 38:ab582987926e 659 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 660 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 661 acktcp[2]=ack>>8;
nixnax 67:a63e3486bcda 662 acktcp[3]=ack>>0; // save ack 32-bit integer
nixnax 38:ab582987926e 663
nixnax 38:ab582987926e 664 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 665 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 666 seqtcp[2]=seq>>8;
nixnax 67:a63e3486bcda 667 seqtcp[3]=seq>>0; // save seq 32-bit integer
nixnax 38:ab582987926e 668
nixnax 38:ab582987926e 669 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 670
nixnax 38:ab582987926e 671 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 672 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 673 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 674 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 675 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 676
nixnax 38:ab582987926e 677 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 678
nixnax 61:b3c1a04efd0a 679 headercheck[0]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 680 headercheck[1]=0; // IP header checksum
nixnax 61:b3c1a04efd0a 681 headerCheckSum(); // calculate the IP header checksum
nixnax 63:9253b0e1b7d8 682
nixnax 64:677b9713a120 683 // 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 684 // 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 685
nixnax 62:f192926e42f1 686 char * pseudoHeader = s-12; // mark the start of the TCP pseudo-header
nixnax 67:a63e3486bcda 687 memcpy(tempHold, pseudoHeader, 12); // preserve the 12 bytes of the IP header where the TCP pseudo-Header will be built
nixnax 61:b3c1a04efd0a 688 memcpy( pseudoHeader+0, srcAdr, 8); // IP source and destination addresses from IP header
nixnax 61:b3c1a04efd0a 689 memset( pseudoHeader+8, 0, 1); // reserved, set to zero
nixnax 61:b3c1a04efd0a 690 memset( pseudoHeader+9, protocolIP, 1); // protocol from IP header
nixnax 62:f192926e42f1 691 memset( pseudoHeader+10, tcpSize>>8, 1); // size of IP data (TCP packet size)
nixnax 62:f192926e42f1 692 memset( pseudoHeader+11, tcpSize, 1); // size of IP data (TCP packet size)
nixnax 38:ab582987926e 693
nixnax 61:b3c1a04efd0a 694 // pseudo-header built, now we can calculate TCP checksum
nixnax 63:9253b0e1b7d8 695
nixnax 29:30de79d658f6 696 checksumtcp[0]=0;
nixnax 29:30de79d658f6 697 checksumtcp[1]=0;
nixnax 62:f192926e42f1 698 int pseudoHeaderSum=dataCheckSum(pseudoHeader,tcpSize+12); // calculate the TCP checksum starting at the pseudo-header
nixnax 61:b3c1a04efd0a 699 checksumtcp[0]=pseudoHeaderSum>>8;
nixnax 61:b3c1a04efd0a 700 checksumtcp[1]=pseudoHeaderSum;
nixnax 61:b3c1a04efd0a 701 memcpy( s-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
nixnax 60:2b770949c911 702
nixnax 36:2a9b457f8276 703 if (fastResponse==1) {
nixnax 36:2a9b457f8276 704 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 705 } else {
nixnax 68:0b74763ae67f 706 // normally, you wait 200 ms before sending a TCP packet
nixnax 68:0b74763ae67f 707 // remove the wait to respond faster
nixnax 68:0b74763ae67f 708 // wait(0.2);
nixnax 36:2a9b457f8276 709 }
nixnax 38:ab582987926e 710 sendFrame(); // All done! Send the TCP packet
nixnax 38:ab582987926e 711 ppp.seq = ppp.seq + dataLen; // increase OUR sequence by the outgoing data length - for the next round
nixnax 29:30de79d658f6 712 }
nixnax 26:11f4eb2663a7 713
nixnax 29:30de79d658f6 714 void dumpDataTCP()
nixnax 29:30de79d658f6 715 {
nixnax 26:11f4eb2663a7 716 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 717 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 718 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 719 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 720 if (v1) {
nixnax 42:4de44be70bfd 721 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 722 }
nixnax 29:30de79d658f6 723 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 724 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 725 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 726 }
nixnax 29:30de79d658f6 727 }
nixnax 26:11f4eb2663a7 728
nixnax 29:30de79d658f6 729 void TCPpacket()
nixnax 29:30de79d658f6 730 {
nixnax 26:11f4eb2663a7 731 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 732 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 733 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 734 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 735 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 736 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 737 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 738 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 739 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 740 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 741 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 742 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 743 #endif
nixnax 26:11f4eb2663a7 744 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 745 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 746
nixnax 55:43faae812be3 747 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 748 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 749 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 750 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 751 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 752 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 753 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 754 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 755 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 756 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 757 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 758 #endif
nixnax 29:30de79d658f6 759 char srcIP [16];
nixnax 29:30de79d658f6 760 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 761 char dstIP [16];
nixnax 29:30de79d658f6 762 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 763 if (v0) {
nixnax 42:4de44be70bfd 764 debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 29:30de79d658f6 765 }
nixnax 29:30de79d658f6 766 if (v0) {
nixnax 42:4de44be70bfd 767 debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 768 }
nixnax 28:1aa629be05e7 769 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 770 dumpDataTCP();
nixnax 26:11f4eb2663a7 771 tcpHandler();
nixnax 11:f58998c24f0b 772 }
nixnax 11:f58998c24f0b 773
nixnax 29:30de79d658f6 774 void otherProtocol()
nixnax 29:30de79d658f6 775 {
nixnax 64:677b9713a120 776 debug("Other IP protocol");
nixnax 29:30de79d658f6 777 }
nixnax 26:11f4eb2663a7 778
nixnax 29:30de79d658f6 779 void IPframe()
nixnax 29:30de79d658f6 780 {
nixnax 10:74f8233f72c0 781 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 782 switch (protocol) {
nixnax 29:30de79d658f6 783 case 1:
nixnax 29:30de79d658f6 784 ICMPpacket();
nixnax 29:30de79d658f6 785 break;
nixnax 29:30de79d658f6 786 case 2:
nixnax 29:30de79d658f6 787 IGMPpacket();
nixnax 29:30de79d658f6 788 break;
nixnax 29:30de79d658f6 789 case 17:
nixnax 29:30de79d658f6 790 UDPpacket();
nixnax 29:30de79d658f6 791 break;
nixnax 29:30de79d658f6 792 case 6:
nixnax 29:30de79d658f6 793 TCPpacket();
nixnax 29:30de79d658f6 794 break;
nixnax 29:30de79d658f6 795 default:
nixnax 29:30de79d658f6 796 otherProtocol();
nixnax 29:30de79d658f6 797 }
nixnax 29:30de79d658f6 798 }
nixnax 9:0992486d4a30 799
nixnax 29:30de79d658f6 800 void LCPconfReq()
nixnax 29:30de79d658f6 801 {
nixnax 64:677b9713a120 802 debug("LCP Config ");
nixnax 9:0992486d4a30 803 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 804 ppp.pkt.buf[4]=4; // allow only no options
nixnax 64:677b9713a120 805 debug("Reject\n");
nixnax 29:30de79d658f6 806 sendFrame();
nixnax 9:0992486d4a30 807 } else {
nixnax 9:0992486d4a30 808 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 64:677b9713a120 809 debug("Ack\n");
nixnax 9:0992486d4a30 810 sendFrame();
nixnax 64:677b9713a120 811 debug("LCP Ask\n");
nixnax 11:f58998c24f0b 812 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 813 sendFrame();
nixnax 9:0992486d4a30 814 }
nixnax 9:0992486d4a30 815 }
nixnax 9:0992486d4a30 816
nixnax 29:30de79d658f6 817 void LCPconfAck()
nixnax 29:30de79d658f6 818 {
nixnax 64:677b9713a120 819 debug("LCP Ack\n");
nixnax 29:30de79d658f6 820 }
nixnax 9:0992486d4a30 821
nixnax 29:30de79d658f6 822 void LCPend()
nixnax 29:30de79d658f6 823 {
nixnax 64:677b9713a120 824 debug("LCP End\n");
nixnax 29:30de79d658f6 825 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 826 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 827 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 828 }
nixnax 9:0992486d4a30 829
nixnax 29:30de79d658f6 830 void LCPother()
nixnax 29:30de79d658f6 831 {
nixnax 64:677b9713a120 832 debug("LCP Other\n");
nixnax 29:30de79d658f6 833 dumpFrame();
nixnax 29:30de79d658f6 834 }
nixnax 29:30de79d658f6 835
nixnax 29:30de79d658f6 836 void LCPframe()
nixnax 29:30de79d658f6 837 {
nixnax 29:30de79d658f6 838 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 839 switch (code) {
nixnax 29:30de79d658f6 840 case 1:
nixnax 29:30de79d658f6 841 LCPconfReq();
nixnax 29:30de79d658f6 842 break; // config request
nixnax 29:30de79d658f6 843 case 2:
nixnax 29:30de79d658f6 844 LCPconfAck();
nixnax 29:30de79d658f6 845 break; // config ack
nixnax 29:30de79d658f6 846 case 5:
nixnax 29:30de79d658f6 847 LCPend();
nixnax 29:30de79d658f6 848 break; // end connection
nixnax 29:30de79d658f6 849 default:
nixnax 29:30de79d658f6 850 LCPother();
nixnax 29:30de79d658f6 851 }
nixnax 9:0992486d4a30 852 }
nixnax 9:0992486d4a30 853
nixnax 29:30de79d658f6 854 void discardedFrame()
nixnax 29:30de79d658f6 855 {
nixnax 29:30de79d658f6 856 if (v0) {
nixnax 71:965619fedb3a 857 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 858 }
nixnax 9:0992486d4a30 859 }
nixnax 9:0992486d4a30 860
nixnax 29:30de79d658f6 861 void determinePacketType()
nixnax 29:30de79d658f6 862 {
nixnax 29:30de79d658f6 863 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 64:677b9713a120 864 debug("byte0 != ff\n");
nixnax 29:30de79d658f6 865 return;
nixnax 29:30de79d658f6 866 }
nixnax 29:30de79d658f6 867 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 64:677b9713a120 868 debug("byte1 != 3\n");
nixnax 29:30de79d658f6 869 return;
nixnax 29:30de79d658f6 870 }
nixnax 29:30de79d658f6 871 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 64:677b9713a120 872 debug("byte2 != 21\n");
nixnax 29:30de79d658f6 873 return;
nixnax 29:30de79d658f6 874 }
nixnax 9:0992486d4a30 875 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 876 switch (packetType) {
nixnax 29:30de79d658f6 877 case 0xc0:
nixnax 29:30de79d658f6 878 LCPframe();
nixnax 29:30de79d658f6 879 break; // link control
nixnax 29:30de79d658f6 880 case 0x80:
nixnax 29:30de79d658f6 881 IPCPframe();
nixnax 29:30de79d658f6 882 break; // IP control
nixnax 29:30de79d658f6 883 case 0x00:
nixnax 29:30de79d658f6 884 IPframe();
nixnax 29:30de79d658f6 885 break; // IP itself
nixnax 29:30de79d658f6 886 default:
nixnax 29:30de79d658f6 887 discardedFrame();
nixnax 9:0992486d4a30 888 }
nixnax 29:30de79d658f6 889 }
nixnax 9:0992486d4a30 890
nixnax 50:ad4e7c3c88e5 891 void wait_for_HDLC_frame()
nixnax 50:ad4e7c3c88e5 892 {
nixnax 50:ad4e7c3c88e5 893 while ( rxbufNotEmpty() ) {
nixnax 50:ad4e7c3c88e5 894 int rx = pc_getBuf();
nixnax 50:ad4e7c3c88e5 895 if (ppp.hdlc.frameBusy) {
nixnax 50:ad4e7c3c88e5 896 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 897 ppp.hdlc.frameBusy=0; // done gathering frame
nixnax 50:ad4e7c3c88e5 898 if (ppp.rx.tail == 0) { // did we just wrap around?
nixnax 50:ad4e7c3c88e5 899 ppp.hdlc.frameEndIndex=BUFLEN-1; // wrap back to end of buffer
nixnax 51:a86d56844324 900 } else {
nixnax 50:ad4e7c3c88e5 901 ppp.hdlc.frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 50:ad4e7c3c88e5 902 }
nixnax 50:ad4e7c3c88e5 903 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex);
nixnax 50:ad4e7c3c88e5 904 }
nixnax 50:ad4e7c3c88e5 905 } else {
nixnax 50:ad4e7c3c88e5 906 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 907 ppp.hdlc.frameBusy=1; // start gathering frame
nixnax 50:ad4e7c3c88e5 908 ppp.hdlc.frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 50:ad4e7c3c88e5 909 }
nixnax 50:ad4e7c3c88e5 910 }
nixnax 50:ad4e7c3c88e5 911 }
nixnax 50:ad4e7c3c88e5 912 }
nixnax 50:ad4e7c3c88e5 913
nixnax 29:30de79d658f6 914 void scanForConnectString()
nixnax 29:30de79d658f6 915 {
nixnax 9:0992486d4a30 916 if ( ppp.online==0 ) {
nixnax 71:965619fedb3a 917 // look for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 71:965619fedb3a 918 char * clientFound = strstr( (char *)rxbufppp, "CLIENTCLIENT" );
nixnax 29:30de79d658f6 919 if( clientFound ) {
nixnax 57:8deab70fef2e 920 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't find it again
nixnax 71:965619fedb3a 921 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 71:965619fedb3a 922 pc.printf("CLIENTSERVER");
nixnax 71:965619fedb3a 923 ppp.online=1; // we are connected, so stop looking for the string
nixnax 64:677b9713a120 924 debug("Connect string found\n");
nixnax 9:0992486d4a30 925 }
nixnax 9:0992486d4a30 926 }
nixnax 9:0992486d4a30 927 }
nixnax 9:0992486d4a30 928
nixnax 0:2cf4880c312a 929 int main()
nixnax 0:2cf4880c312a 930 {
nixnax 14:c65831c25aaa 931 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 932 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 49:2213f9c132b2 933 xx.baud(115200); // second serial port for debug messages
nixnax 9:0992486d4a30 934 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 935 #endif
nixnax 9:0992486d4a30 936 pppInitStruct(); // initialize all the PPP properties
nixnax 9:0992486d4a30 937 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 0:2cf4880c312a 938 while(1) {
nixnax 51:a86d56844324 939 scanForConnectString(); // respond to connect command from windows dial up networking
nixnax 50:ad4e7c3c88e5 940 wait_for_HDLC_frame();
nixnax 7:ab147f5e97ac 941 }
nixnax 7:ab147f5e97ac 942 }