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@77:abf92baebb42, 2017-07-08 (annotated)

Committer:
nixnax
Date:
Sat Jul 08 10:10:12 2017 +0000
Revision:
77:abf92baebb42
Parent:
76:00e208cceb8b
Child:
78:809c2631a5eb
New mbed library; Compile errors when serial debug is on; Seq and Ack number handling

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 77:abf92baebb42 45 // verbosity flag used in debug printouts - change to 0 to see less debug info. Lots of interesting info.
nixnax 77:abf92baebb42 46 #define v2 0
nixnax 29:30de79d658f6 47
nixnax 66:f005b9fdf4d1 48 // this is the webpage we serve when we get an HTTP request
nixnax 72:ad3d12753acf 49 // keep size under 900 bytes to fit into a single frame
nixnax 66:f005b9fdf4d1 50 const static char ourWebPage[] = "\
nixnax 66:f005b9fdf4d1 51 <!DOCTYPE html>\
nixnax 66:f005b9fdf4d1 52 <html>\
nixnax 66:f005b9fdf4d1 53 <head>\
nixnax 66:f005b9fdf4d1 54 <title>mbed-PPP-Blinky</title>\
nixnax 66:f005b9fdf4d1 55 <script>\
nixnax 66:f005b9fdf4d1 56 window.onload=function(){\
nixnax 66:f005b9fdf4d1 57 setInterval(function(){function x(){return document.getElementById('w');};\
nixnax 66:f005b9fdf4d1 58 x().textContent = parseInt(x().textContent)+1;},100);};\
nixnax 66:f005b9fdf4d1 59 </script>\
nixnax 66:f005b9fdf4d1 60 </head>\
nixnax 66:f005b9fdf4d1 61 <body style=\"font-family: sans-serif; font-size:30px; color:#807070\">\
nixnax 66:f005b9fdf4d1 62 <h1>mbed PPP-Blinky Up and Running</h1>\
nixnax 66:f005b9fdf4d1 63 <h1 id=\"w\" style=\"text-align:center;\">0</h1>\
nixnax 66:f005b9fdf4d1 64 <h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\
nixnax 66:f005b9fdf4d1 65 </body>\
nixnax 69:23f560087c16 66 </html>"; // around 464 bytes long
nixnax 69:23f560087c16 67
nixnax 69:23f560087c16 68
nixnax 66:f005b9fdf4d1 69
nixnax 73:2f56ec87dbe9 70 // The serial port on your mbed hardware. Your PC should be configured to view this port as a standard dial-up networking modem.
nixnax 73:2f56ec87dbe9 71 // On Windows the model type of the modem should be selected as "Communications cable between two computers"
nixnax 72:ad3d12753acf 72 // The modem baud rate should be set to 115200 baud
nixnax 72:ad3d12753acf 73 // See instructions at the top.
nixnax 73:2f56ec87dbe9 74 // On a typical mbed hardware platform this serial port is a USB virtual com port (VCP) and the USB serial driver is supplied by the board vendor.
nixnax 73:2f56ec87dbe9 75 Serial pc(USBTX, USBRX); // usb virtual com port for mbed hardware
nixnax 29:30de79d658f6 76
nixnax 29:30de79d658f6 77 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 78
nixnax 66:f005b9fdf4d1 79 // the standard hdlc frame start/end character. It's the tilde character "~"
nixnax 4:a469050d5b80 80 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 81
nixnax 29:30de79d658f6 82 // the serial port receive buffer and packet buffer
nixnax 0:2cf4880c312a 83
nixnax 29:30de79d658f6 84 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 85 struct pppType {
nixnax 38:ab582987926e 86 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 87 int ident; // our IP ident value
nixnax 38:ab582987926e 88 unsigned int seq; // our TCP sequence number
nixnax 38:ab582987926e 89 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 90 int ledState; // state of LED1
nixnax 4:a469050d5b80 91 struct {
nixnax 72:ad3d12753acf 92 #define BUFLEN (1<<13)
nixnax 72:ad3d12753acf 93 char buf[BUFLEN]; // BUFLEN MUST be a power of two because we use & operator for fast wrap-around in rxHandler
nixnax 72:ad3d12753acf 94 //char * buf;
nixnax 29:30de79d658f6 95 volatile int head;
nixnax 29:30de79d658f6 96 volatile int tail;
nixnax 38:ab582987926e 97 } rx; // serial port objects
nixnax 4:a469050d5b80 98 struct {
nixnax 38:ab582987926e 99 int len; // number of bytes in buffer
nixnax 38:ab582987926e 100 int crc; // PPP CRC (frame check)
nixnax 72:ad3d12753acf 101 //char * buf; // the actual buffer
nixnax 77:abf92baebb42 102 #define TCP_max_size 3300
nixnax 77:abf92baebb42 103 char buf[TCP_max_size]; // send and receive buffer large enough for unstuffed (decoded) hdlc frames
nixnax 38:ab582987926e 104 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 105 struct {
nixnax 50:ad4e7c3c88e5 106 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 107 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 108 int frameBusy; // busy capturing a frame
nixnax 50:ad4e7c3c88e5 109 } hdlc; // hdlc frame objects
nixnax 29:30de79d658f6 110 };
nixnax 31:e000c1b9c565 111
nixnax 29:30de79d658f6 112 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 113
nixnax 60:2b770949c911 114 // Initialize our globals
nixnax 29:30de79d658f6 115 void pppInitStruct()
nixnax 29:30de79d658f6 116 {
nixnax 29:30de79d658f6 117 ppp.online=0;
nixnax 29:30de79d658f6 118 ppp.rx.tail=0;
nixnax 29:30de79d658f6 119 ppp.rx.head=0;
nixnax 29:30de79d658f6 120 ppp.pkt.len=0;
nixnax 29:30de79d658f6 121 ppp.ident=0;
nixnax 35:e7068df4d971 122 ppp.seq=1000;
nixnax 29:30de79d658f6 123 ppp.ledState=0;
nixnax 50:ad4e7c3c88e5 124 ppp.hdlc.frameBusy=0;
nixnax 29:30de79d658f6 125 }
nixnax 26:11f4eb2663a7 126
nixnax 43:aa57db08995d 127 void led1Toggle()
nixnax 43:aa57db08995d 128 {
nixnax 43:aa57db08995d 129 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 130 led1 = ppp.ledState;
nixnax 43:aa57db08995d 131 }
nixnax 43:aa57db08995d 132
nixnax 29:30de79d658f6 133 void crcReset()
nixnax 29:30de79d658f6 134 {
nixnax 29:30de79d658f6 135 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 136 }
nixnax 4:a469050d5b80 137
nixnax 29:30de79d658f6 138 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 139 {
nixnax 29:30de79d658f6 140 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 141 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 142 x>>=1;
nixnax 29:30de79d658f6 143 }
nixnax 29:30de79d658f6 144 }
nixnax 29:30de79d658f6 145
nixnax 29:30de79d658f6 146 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 147 {
nixnax 31:e000c1b9c565 148 crcReset();
nixnax 31:e000c1b9c565 149 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 150 return ppp.crc;
nixnax 29:30de79d658f6 151 }
nixnax 0:2cf4880c312a 152
nixnax 0:2cf4880c312a 153 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 154 {
nixnax 17:4918c893d802 155 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 156 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 157 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 158 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 159 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 160 }
nixnax 0:2cf4880c312a 161 }
nixnax 0:2cf4880c312a 162
nixnax 22:00df34cd4d7e 163 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 164 {
nixnax 22:00df34cd4d7e 165 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 166 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 167 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 168 return emptyStatus;
nixnax 0:2cf4880c312a 169 }
nixnax 0:2cf4880c312a 170
nixnax 0:2cf4880c312a 171 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 172 {
nixnax 63:9253b0e1b7d8 173 __disable_irq(); // critical section start
nixnax 63:9253b0e1b7d8 174 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 63:9253b0e1b7d8 175 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 63:9253b0e1b7d8 176 __enable_irq(); // critical section end
nixnax 63:9253b0e1b7d8 177 return x;
nixnax 0:2cf4880c312a 178 }
nixnax 0:2cf4880c312a 179
nixnax 50:ad4e7c3c88e5 180 void processHDLCFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 181 {
nixnax 38:ab582987926e 182 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 183 if(start==end) {
nixnax 29:30de79d658f6 184 return;
nixnax 29:30de79d658f6 185 }
nixnax 9:0992486d4a30 186 crcReset();
nixnax 9:0992486d4a30 187 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 188 ppp.pkt.len=0;
nixnax 9:0992486d4a30 189 int unstuff=0;
nixnax 17:4918c893d802 190 int idx = start;
nixnax 17:4918c893d802 191 while(1) {
nixnax 9:0992486d4a30 192 if (unstuff==0) {
nixnax 72:ad3d12753acf 193 if (ppp.rx.buf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 194 else {
nixnax 72:ad3d12753acf 195 *dest = ppp.rx.buf[idx];
nixnax 29:30de79d658f6 196 ppp.pkt.len++;
nixnax 29:30de79d658f6 197 dest++;
nixnax 72:ad3d12753acf 198 crcDo(ppp.rx.buf[idx]);
nixnax 29:30de79d658f6 199 }
nixnax 66:f005b9fdf4d1 200 } else { // unstuff characters prefixed with 0x7d
nixnax 72:ad3d12753acf 201 *dest = ppp.rx.buf[idx]^0x20;
nixnax 29:30de79d658f6 202 ppp.pkt.len++;
nixnax 29:30de79d658f6 203 dest++;
nixnax 72:ad3d12753acf 204 crcDo(ppp.rx.buf[idx]^0x20);
nixnax 9:0992486d4a30 205 unstuff=0;
nixnax 9:0992486d4a30 206 }
nixnax 17:4918c893d802 207 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 208 if (idx == end) break;
nixnax 9:0992486d4a30 209 }
nixnax 29:30de79d658f6 210 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 211 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 212 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 213 determinePacketType();
nixnax 29:30de79d658f6 214 } else if (v0) {
nixnax 66:f005b9fdf4d1 215 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 216 }
nixnax 9:0992486d4a30 217 }
nixnax 9:0992486d4a30 218
nixnax 38:ab582987926e 219 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 220 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 221 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 222 void dumpFrame()
nixnax 29:30de79d658f6 223 {
nixnax 42:4de44be70bfd 224 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 225 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 226 }
nixnax 16:cb0b80c24ba2 227
nixnax 29:30de79d658f6 228 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 229 {
nixnax 29:30de79d658f6 230 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 231 pc.putc(0x7d);
nixnax 66:f005b9fdf4d1 232 pc.putc(ch^0x20); // these characters need special handling
nixnax 29:30de79d658f6 233 } else {
nixnax 29:30de79d658f6 234 pc.putc(ch);
nixnax 29:30de79d658f6 235 }
nixnax 11:f58998c24f0b 236 }
nixnax 9:0992486d4a30 237
nixnax 66:f005b9fdf4d1 238 void sendFrame() // send a PPP frame in HDLC format
nixnax 29:30de79d658f6 239 {
nixnax 17:4918c893d802 240 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 241 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 242 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 243 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 244 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 245 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 246 }
nixnax 9:0992486d4a30 247
nixnax 66:f005b9fdf4d1 248 void ipConfigRequestHandler()
nixnax 29:30de79d658f6 249 {
nixnax 64:677b9713a120 250 debug("IPCP Conf ");
nixnax 9:0992486d4a30 251 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 66:f005b9fdf4d1 252 debug("Rej\n"); // reject any options that are requested
nixnax 9:0992486d4a30 253 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 254 sendFrame();
nixnax 9:0992486d4a30 255 } else {
nixnax 64:677b9713a120 256 debug("Ack\n");
nixnax 9:0992486d4a30 257 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 258 sendFrame(); // acknowledge
nixnax 64:677b9713a120 259 debug("IPCP Ask\n");
nixnax 9:0992486d4a30 260 // send our own request now
nixnax 12:db0dc91f0231 261 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 262 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 263 sendFrame(); // this is our request
nixnax 9:0992486d4a30 264 }
nixnax 9:0992486d4a30 265 }
nixnax 9:0992486d4a30 266
nixnax 29:30de79d658f6 267 void ipAckHandler()
nixnax 29:30de79d658f6 268 {
nixnax 64:677b9713a120 269 debug("IPCP Grant\n");
nixnax 29:30de79d658f6 270 }
nixnax 9:0992486d4a30 271
nixnax 29:30de79d658f6 272 void ipNackHandler()
nixnax 29:30de79d658f6 273 {
nixnax 64:677b9713a120 274 debug("IPCP Nack\n");
nixnax 29:30de79d658f6 275 }
nixnax 9:0992486d4a30 276
nixnax 29:30de79d658f6 277 void ipDefaultHandler()
nixnax 29:30de79d658f6 278 {
nixnax 64:677b9713a120 279 debug("IPCP Other\n");
nixnax 29:30de79d658f6 280 }
nixnax 29:30de79d658f6 281
nixnax 29:30de79d658f6 282 void IPCPframe()
nixnax 29:30de79d658f6 283 {
nixnax 9:0992486d4a30 284 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 285 switch (code) {
nixnax 29:30de79d658f6 286 case 1:
nixnax 66:f005b9fdf4d1 287 ipConfigRequestHandler();
nixnax 29:30de79d658f6 288 break;
nixnax 29:30de79d658f6 289 case 2:
nixnax 29:30de79d658f6 290 ipAckHandler();
nixnax 29:30de79d658f6 291 break;
nixnax 29:30de79d658f6 292 case 3:
nixnax 29:30de79d658f6 293 ipNackHandler();
nixnax 29:30de79d658f6 294 break;
nixnax 29:30de79d658f6 295 default:
nixnax 29:30de79d658f6 296 ipDefaultHandler();
nixnax 9:0992486d4a30 297 }
nixnax 29:30de79d658f6 298 }
nixnax 9:0992486d4a30 299
nixnax 29:30de79d658f6 300 void UDPpacket()
nixnax 29:30de79d658f6 301 {
nixnax 12:db0dc91f0231 302 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 303 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 304 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 63:9253b0e1b7d8 305 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 306 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 307 char * udpDst = udpBlock+2; // destination port
nixnax 63:9253b0e1b7d8 308 #endif
nixnax 12:db0dc91f0231 309 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 310 char * udpInf = udpBlock+8; // actual start of info
nixnax 63:9253b0e1b7d8 311 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 312 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 313 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 314 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 315 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 316 #endif
nixnax 29:30de79d658f6 317 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 318 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 42:4de44be70bfd 319 if(v1) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 73:2f56ec87dbe9 320 if(v1) debug("%d.%d.%d.%d:%d ", dstIP[0],dstIP[1],dstIP[2],dstIP[3],dstPort);
nixnax 42:4de44be70bfd 321 debug("Len %d ", udpLength);
nixnax 29:30de79d658f6 322 int printSize = udpLength;
nixnax 29:30de79d658f6 323 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 324 if (v0) {
nixnax 29:30de79d658f6 325 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 326 char ch = udpInf[i];
nixnax 29:30de79d658f6 327 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 328 debug("%c", ch);
nixnax 29:30de79d658f6 329 } else {
nixnax 64:677b9713a120 330 debug("_");
nixnax 29:30de79d658f6 331 }
nixnax 29:30de79d658f6 332 }
nixnax 64:677b9713a120 333 debug("\n");
nixnax 29:30de79d658f6 334 }
nixnax 12:db0dc91f0231 335 }
nixnax 11:f58998c24f0b 336
nixnax 76:00e208cceb8b 337 unsigned int dataCheckSum(unsigned char * ptr, int len)
nixnax 29:30de79d658f6 338 {
nixnax 77:abf92baebb42 339
nixnax 75:0d513869231f 340 unsigned int sum=0;
nixnax 76:00e208cceb8b 341 unsigned char placeHolder;
nixnax 29:30de79d658f6 342 if (len&1) {
nixnax 76:00e208cceb8b 343 placeHolder = ptr[len]; // when length is odd stuff in a zero byte
nixnax 76:00e208cceb8b 344 ptr[len]=0;
nixnax 29:30de79d658f6 345 }
nixnax 29:30de79d658f6 346 for (int i=0; i<len/2; i++) {
nixnax 76:00e208cceb8b 347 unsigned int hi = *ptr;
nixnax 29:30de79d658f6 348 ptr++;
nixnax 76:00e208cceb8b 349 unsigned int lo = *ptr;
nixnax 29:30de79d658f6 350 ptr++;
nixnax 76:00e208cceb8b 351 unsigned int val = ( (hi<<8) | lo );
nixnax 11:f58998c24f0b 352 sum = sum + val;
nixnax 11:f58998c24f0b 353 }
nixnax 29:30de79d658f6 354 if (len&1) {
nixnax 76:00e208cceb8b 355 ptr[len] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 356 }
nixnax 76:00e208cceb8b 357 sum = (sum & 0xffff) + (sum>>16);
nixnax 76:00e208cceb8b 358 sum = (sum & 0xffff) + (sum>>16); // sum one more time to catch any carry from the carry
nixnax 12:db0dc91f0231 359 return ~sum;
nixnax 29:30de79d658f6 360 }
nixnax 11:f58998c24f0b 361
nixnax 29:30de79d658f6 362 void headerCheckSum()
nixnax 29:30de79d658f6 363 {
nixnax 11:f58998c24f0b 364 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 365 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 366 int sum=0;
nixnax 11:f58998c24f0b 367
nixnax 29:30de79d658f6 368 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 369 int hi = *ptr;
nixnax 29:30de79d658f6 370 ptr++;
nixnax 29:30de79d658f6 371 int lo = *ptr;
nixnax 29:30de79d658f6 372 ptr++;
nixnax 11:f58998c24f0b 373 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 374 sum = sum + val;
nixnax 11:f58998c24f0b 375 }
nixnax 11:f58998c24f0b 376 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 377 sum = ~sum;
nixnax 11:f58998c24f0b 378 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 379 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 380 }
nixnax 9:0992486d4a30 381
nixnax 29:30de79d658f6 382 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 383 {
nixnax 12:db0dc91f0231 384 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 385 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 386 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 387 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 388 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 389 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 390 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 391 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 392 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 393 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 394 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 395 char * dstAdr = ipPkt+16;
nixnax 63:9253b0e1b7d8 396 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 397 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 398 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 63:9253b0e1b7d8 399 #endif
nixnax 77:abf92baebb42 400 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 401 debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 402 char src[4];
nixnax 29:30de79d658f6 403 char dst[4];
nixnax 12:db0dc91f0231 404 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 405 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 406 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 407 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 408 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 409 chkSum[0]=0;
nixnax 29:30de79d658f6 410 chkSum[1]=0;
nixnax 12:db0dc91f0231 411 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 412 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 413 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 414 icmpSum[0]=0;
nixnax 29:30de79d658f6 415 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 416 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 76:00e208cceb8b 417 unsigned int sum = dataCheckSum( (unsigned char *)icmpType, icmpLength); // this checksum on icmp data portion
nixnax 76:00e208cceb8b 418 icmpSum[0]=(sum>>8)&0xff;
nixnax 76:00e208cceb8b 419 icmpSum[1]=(sum )&0xff; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 420
nixnax 16:cb0b80c24ba2 421 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 422 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 423 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 424 if (v0) {
nixnax 29:30de79d658f6 425 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 426 char ch = icmpData[i];
nixnax 29:30de79d658f6 427 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 428 debug("%c",ch);
nixnax 29:30de79d658f6 429 } else {
nixnax 64:677b9713a120 430 debug("_");
nixnax 29:30de79d658f6 431 }
nixnax 29:30de79d658f6 432 }
nixnax 64:677b9713a120 433 debug("\n");
nixnax 29:30de79d658f6 434 }
nixnax 15:b0154c910143 435 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 436
nixnax 12:db0dc91f0231 437 } else {
nixnax 29:30de79d658f6 438 if (v0) {
nixnax 42:4de44be70bfd 439 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 440 }
nixnax 11:f58998c24f0b 441 }
nixnax 11:f58998c24f0b 442 }
nixnax 11:f58998c24f0b 443
nixnax 29:30de79d658f6 444 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 445 {
nixnax 29:30de79d658f6 446 if (v0) {
nixnax 42:4de44be70bfd 447 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 448 }
nixnax 29:30de79d658f6 449 }
nixnax 11:f58998c24f0b 450
nixnax 29:30de79d658f6 451 void dumpHeaderIP ()
nixnax 29:30de79d658f6 452 {
nixnax 26:11f4eb2663a7 453 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 454 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 455 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 456 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 457 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 458 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 459 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 460 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 461 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 462 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 463 char * protocol = ipPkt+9; // 1 byte
nixnax 77:abf92baebb42 464 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 465 #endif
nixnax 26:11f4eb2663a7 466 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 467 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 468
nixnax 55:43faae812be3 469 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 470 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 471 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 472 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 473 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 474 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 475 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 476 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 477 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 478 int protocolIP = protocol[0];
nixnax 76:00e208cceb8b 479 unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 480 #endif
nixnax 55:43faae812be3 481
nixnax 29:30de79d658f6 482 char srcIP [16];
nixnax 29:30de79d658f6 483 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 484 char dstIP [16];
nixnax 29:30de79d658f6 485 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 42:4de44be70bfd 486 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 487 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 488 }
nixnax 26:11f4eb2663a7 489
nixnax 29:30de79d658f6 490 void dumpHeaderTCP()
nixnax 29:30de79d658f6 491 {
nixnax 29:30de79d658f6 492 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 493 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 63:9253b0e1b7d8 494 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 495 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 496 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 63:9253b0e1b7d8 497 #endif
nixnax 29:30de79d658f6 498 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 63:9253b0e1b7d8 499 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 31:e000c1b9c565 500 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 501 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 63:9253b0e1b7d8 502 #endif
nixnax 26:11f4eb2663a7 503 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 504
nixnax 66:f005b9fdf4d1 505 char flagInfo[10]; // text string presentating the TCP flags
nixnax 66:f005b9fdf4d1 506 memset(flagInfo,'.', 9); // fill string with "........."
nixnax 70:713f86229288 507 memset(flagInfo+9,0,1); // null terminate string
nixnax 66:f005b9fdf4d1 508
nixnax 29:30de79d658f6 509 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 510 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 511 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 512 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 513 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 514 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 515 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 516 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 517 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 77:abf92baebb42 518 if (v1) {
nixnax 77:abf92baebb42 519 debug("Flags %s Seq %u Ack %u\n", flagInfo, seq, ack); // show the flags in debug
nixnax 29:30de79d658f6 520 }
nixnax 29:30de79d658f6 521 }
nixnax 29:30de79d658f6 522
nixnax 68:0b74763ae67f 523 int httpResponse(char * dataStart)
nixnax 67:a63e3486bcda 524 {
nixnax 67:a63e3486bcda 525 int n=0; // number of bytes we have printed so far
nixnax 77:abf92baebb42 526 int nHeader; // byte size of HTTP header
nixnax 77:abf92baebb42 527
nixnax 67:a63e3486bcda 528 if(strncmp(dataStart, "GET / HTTP/1.1", 14) == 0 ) {
nixnax 67:a63e3486bcda 529 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 67:a63e3486bcda 530 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 67:a63e3486bcda 531 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 67:a63e3486bcda 532 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 74:7409fbeabb2e 533 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 67:a63e3486bcda 534 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 77:abf92baebb42 535 nHeader=n; // size of HTTP header
nixnax 67:a63e3486bcda 536 // this is where we insert our web page into the buffer
nixnax 67:a63e3486bcda 537 n=n+sprintf(n+dataStart,"%s\r\n", ourWebPage);
nixnax 67:a63e3486bcda 538
nixnax 68:0b74763ae67f 539 #define CONTENTLENGTHSIZE 5
nixnax 67:a63e3486bcda 540 char contentLengthString[CONTENTLENGTHSIZE+1]; // temporary buffer to create Content-Length string
nixnax 68:0b74763ae67f 541 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 67:a63e3486bcda 542 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 67:a63e3486bcda 543
nixnax 74:7409fbeabb2e 544 } else { // all remaining requests get 404 Not Found response and heap size
nixnax 67:a63e3486bcda 545 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 67:a63e3486bcda 546 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 67:a63e3486bcda 547 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 67:a63e3486bcda 548 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 74:7409fbeabb2e 549 n=n+sprintf(n+dataStart,"Connection: close\r\n"); // close connection immediately
nixnax 74:7409fbeabb2e 550 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 77:abf92baebb42 551 nHeader=n; // size of HTTP header
nixnax 67:a63e3486bcda 552
nixnax 67:a63e3486bcda 553 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head></head>"); // html start
nixnax 74:7409fbeabb2e 554 n=n+sprintf(n+dataStart,"<body><h1>File Not Found. Stack=0x%08x</h1></body>",&nHeader);
nixnax 67:a63e3486bcda 555 n=n+sprintf(n+dataStart,"</html>\r\n"); // html end
nixnax 67:a63e3486bcda 556
nixnax 68:0b74763ae67f 557 char contentLengthString[CONTENTLENGTHSIZE+1]; // temporary buffer to create Content-Length string
nixnax 68:0b74763ae67f 558 snprintf(contentLengthString,CONTENTLENGTHSIZE+1,"%*d",CONTENTLENGTHSIZE,n-nHeader); // print Content-Length with leading spaces and fixed width equal to csize
nixnax 68:0b74763ae67f 559 memcpy(dataStart+contentLengthStart, contentLengthString, CONTENTLENGTHSIZE); // copy Content-Length to it's place in the send buffer
nixnax 77:abf92baebb42 560 }
nixnax 77:abf92baebb42 561 if (v2) {
nixnax 77:abf92baebb42 562 debug("HTTP Response: HTTP-header %d HTTP-content %d HTTP-total %d\n",nHeader,n-nHeader,n);
nixnax 77:abf92baebb42 563 }
nixnax 67:a63e3486bcda 564
nixnax 67:a63e3486bcda 565 return n; // total byte size of our response
nixnax 67:a63e3486bcda 566 }
nixnax 67:a63e3486bcda 567
nixnax 67:a63e3486bcda 568
nixnax 29:30de79d658f6 569 void tcpHandler()
nixnax 29:30de79d658f6 570 {
nixnax 26:11f4eb2663a7 571 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 572 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 573 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 574 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 575 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 576 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 577 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 578 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 579 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 580 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 581
nixnax 29:30de79d658f6 582 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 583 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 584
nixnax 29:30de79d658f6 585 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 586 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 587 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 588 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 589 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 590 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 591 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 592 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 593
nixnax 26:11f4eb2663a7 594 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 595 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 61:b3c1a04efd0a 596 int protocolIP = protocol[0];
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 77:abf92baebb42 602
nixnax 77:abf92baebb42 603 unsigned int ack = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]) + tcpDataSize;
nixnax 77:abf92baebb42 604 unsigned int seq = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 28:1aa629be05e7 605
nixnax 29:30de79d658f6 606 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 607 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 608 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 609 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 610 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 611
nixnax 35:e7068df4d971 612 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 613 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 614 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 615
nixnax 69:23f560087c16 616 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 69:23f560087c16 617 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 69:23f560087c16 618 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 77:abf92baebb42 619
nixnax 69:23f560087c16 620 switch ( flagsTCP ) {
nixnax 69:23f560087c16 621 case TCP_FLAG_ACK:
nixnax 69:23f560087c16 622 if ( tcpDataSize != 1 ) return;
nixnax 69:23f560087c16 623 case TCP_FLAG_SYN:
nixnax 69:23f560087c16 624 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - ack it
nixnax 77:abf92baebb42 625 ack++; // for SYN flag we have to increase sequence by 1
nixnax 69:23f560087c16 626 break;
nixnax 77:abf92baebb42 627 case TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 69:23f560087c16 628 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 69:23f560087c16 629 fastResponse = 1; // we can respond fast to a push
nixnax 69:23f560087c16 630 if ( strncmp(dataStart, "GET ", 4) == 0) { // do we see an http GET command
nixnax 69:23f560087c16 631 dataLen = httpResponse(dataStart); // send an http response
nixnax 69:23f560087c16 632 while((dataLen %4 ) !=0) { // dataLen must be a multiple of four
nixnax 77:abf92baebb42 633 dataLen++; // must be a multiple of four
nixnax 77:abf92baebb42 634 dataStart[dataLen-1]=0; // clear the byte in the buffer
nixnax 69:23f560087c16 635 }
nixnax 69:23f560087c16 636 }
nixnax 69:23f560087c16 637 break;
nixnax 77:abf92baebb42 638 case TCP_FLAG_FIN:
nixnax 69:23f560087c16 639 case TCP_FLAG_FIN | TCP_FLAG_ACK:
nixnax 69:23f560087c16 640 case TCP_FLAG_FIN | TCP_FLAG_ACK | TCP_FLAG_PSH:
nixnax 77:abf92baebb42 641 ack++; // for FIN flag we have to increase sequence by 1
nixnax 69:23f560087c16 642 break;
nixnax 77:abf92baebb42 643 default:
nixnax 69:23f560087c16 644 return; // ignore remaining packets
nixnax 28:1aa629be05e7 645 }
nixnax 77:abf92baebb42 646
nixnax 69:23f560087c16 647 // The TCP flag handling is now done
nixnax 38:ab582987926e 648 // 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 649
nixnax 65:23b17c43aa0f 650 char tempHold[12]; // it's 12 long because we later reuse it when building the TCP pseudo-header
nixnax 60:2b770949c911 651 memcpy(tempHold, srcAdr,4);
nixnax 65:23b17c43aa0f 652 memcpy(srcAdr, dstAdr,4);
nixnax 60:2b770949c911 653 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 654
nixnax 60:2b770949c911 655 memcpy(tempHold, srctcp,2);
nixnax 65:23b17c43aa0f 656 memcpy(srctcp, dsttcp,2);
nixnax 60:2b770949c911 657 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 29:30de79d658f6 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 76:00e208cceb8b 698 unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)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 77:abf92baebb42 708 wait(0.05);
nixnax 36:2a9b457f8276 709 }
nixnax 38:ab582987926e 710 sendFrame(); // All done! Send the TCP packet
nixnax 29:30de79d658f6 711 }
nixnax 26:11f4eb2663a7 712
nixnax 29:30de79d658f6 713 void dumpDataTCP()
nixnax 29:30de79d658f6 714 {
nixnax 26:11f4eb2663a7 715 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 716 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 717 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 718 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 719 if (v1) {
nixnax 42:4de44be70bfd 720 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 721 }
nixnax 29:30de79d658f6 722 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 723 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 724 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 725 }
nixnax 29:30de79d658f6 726 }
nixnax 26:11f4eb2663a7 727
nixnax 29:30de79d658f6 728 void TCPpacket()
nixnax 29:30de79d658f6 729 {
nixnax 26:11f4eb2663a7 730 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 63:9253b0e1b7d8 731 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 732 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 733 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 734 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 735 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 736 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 737 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 738 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 739 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 740 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 741 char * headercheck= ipPkt+10; // 2 bytes
nixnax 63:9253b0e1b7d8 742 #endif
nixnax 26:11f4eb2663a7 743 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 744 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 745
nixnax 55:43faae812be3 746 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 747 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 748 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 749 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 750 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 751 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 752 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 753 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 754 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 755 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 756 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 63:9253b0e1b7d8 757 #endif
nixnax 29:30de79d658f6 758 char srcIP [16];
nixnax 29:30de79d658f6 759 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 760 char dstIP [16];
nixnax 29:30de79d658f6 761 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 762 if (v0) {
nixnax 42:4de44be70bfd 763 debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 29:30de79d658f6 764 }
nixnax 29:30de79d658f6 765 if (v0) {
nixnax 42:4de44be70bfd 766 debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 767 }
nixnax 77:abf92baebb42 768 if (v1) {
nixnax 77:abf92baebb42 769 dumpHeaderTCP();
nixnax 77:abf92baebb42 770 }
nixnax 77:abf92baebb42 771
nixnax 77:abf92baebb42 772 if (v2) {
nixnax 77:abf92baebb42 773 dumpDataTCP();
nixnax 77:abf92baebb42 774 }
nixnax 26:11f4eb2663a7 775 tcpHandler();
nixnax 11:f58998c24f0b 776 }
nixnax 11:f58998c24f0b 777
nixnax 29:30de79d658f6 778 void otherProtocol()
nixnax 29:30de79d658f6 779 {
nixnax 64:677b9713a120 780 debug("Other IP protocol");
nixnax 29:30de79d658f6 781 }
nixnax 26:11f4eb2663a7 782
nixnax 29:30de79d658f6 783 void IPframe()
nixnax 29:30de79d658f6 784 {
nixnax 10:74f8233f72c0 785 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 786 switch (protocol) {
nixnax 29:30de79d658f6 787 case 1:
nixnax 29:30de79d658f6 788 ICMPpacket();
nixnax 29:30de79d658f6 789 break;
nixnax 29:30de79d658f6 790 case 2:
nixnax 29:30de79d658f6 791 IGMPpacket();
nixnax 29:30de79d658f6 792 break;
nixnax 29:30de79d658f6 793 case 17:
nixnax 29:30de79d658f6 794 UDPpacket();
nixnax 29:30de79d658f6 795 break;
nixnax 29:30de79d658f6 796 case 6:
nixnax 29:30de79d658f6 797 TCPpacket();
nixnax 29:30de79d658f6 798 break;
nixnax 29:30de79d658f6 799 default:
nixnax 29:30de79d658f6 800 otherProtocol();
nixnax 29:30de79d658f6 801 }
nixnax 29:30de79d658f6 802 }
nixnax 9:0992486d4a30 803
nixnax 29:30de79d658f6 804 void LCPconfReq()
nixnax 29:30de79d658f6 805 {
nixnax 64:677b9713a120 806 debug("LCP Config ");
nixnax 9:0992486d4a30 807 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 808 ppp.pkt.buf[4]=4; // allow only no options
nixnax 64:677b9713a120 809 debug("Reject\n");
nixnax 29:30de79d658f6 810 sendFrame();
nixnax 9:0992486d4a30 811 } else {
nixnax 9:0992486d4a30 812 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 64:677b9713a120 813 debug("Ack\n");
nixnax 9:0992486d4a30 814 sendFrame();
nixnax 64:677b9713a120 815 debug("LCP Ask\n");
nixnax 11:f58998c24f0b 816 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 817 sendFrame();
nixnax 9:0992486d4a30 818 }
nixnax 9:0992486d4a30 819 }
nixnax 9:0992486d4a30 820
nixnax 29:30de79d658f6 821 void LCPconfAck()
nixnax 29:30de79d658f6 822 {
nixnax 64:677b9713a120 823 debug("LCP Ack\n");
nixnax 29:30de79d658f6 824 }
nixnax 9:0992486d4a30 825
nixnax 29:30de79d658f6 826 void LCPend()
nixnax 29:30de79d658f6 827 {
nixnax 64:677b9713a120 828 debug("LCP End\n");
nixnax 29:30de79d658f6 829 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 830 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 831 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 832 }
nixnax 9:0992486d4a30 833
nixnax 29:30de79d658f6 834 void LCPother()
nixnax 29:30de79d658f6 835 {
nixnax 64:677b9713a120 836 debug("LCP Other\n");
nixnax 29:30de79d658f6 837 dumpFrame();
nixnax 29:30de79d658f6 838 }
nixnax 29:30de79d658f6 839
nixnax 29:30de79d658f6 840 void LCPframe()
nixnax 29:30de79d658f6 841 {
nixnax 29:30de79d658f6 842 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 843 switch (code) {
nixnax 29:30de79d658f6 844 case 1:
nixnax 29:30de79d658f6 845 LCPconfReq();
nixnax 29:30de79d658f6 846 break; // config request
nixnax 29:30de79d658f6 847 case 2:
nixnax 29:30de79d658f6 848 LCPconfAck();
nixnax 29:30de79d658f6 849 break; // config ack
nixnax 29:30de79d658f6 850 case 5:
nixnax 29:30de79d658f6 851 LCPend();
nixnax 29:30de79d658f6 852 break; // end connection
nixnax 29:30de79d658f6 853 default:
nixnax 29:30de79d658f6 854 LCPother();
nixnax 29:30de79d658f6 855 }
nixnax 9:0992486d4a30 856 }
nixnax 9:0992486d4a30 857
nixnax 29:30de79d658f6 858 void discardedFrame()
nixnax 29:30de79d658f6 859 {
nixnax 29:30de79d658f6 860 if (v0) {
nixnax 71:965619fedb3a 861 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 862 }
nixnax 9:0992486d4a30 863 }
nixnax 9:0992486d4a30 864
nixnax 29:30de79d658f6 865 void determinePacketType()
nixnax 29:30de79d658f6 866 {
nixnax 29:30de79d658f6 867 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 64:677b9713a120 868 debug("byte0 != ff\n");
nixnax 29:30de79d658f6 869 return;
nixnax 29:30de79d658f6 870 }
nixnax 29:30de79d658f6 871 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 64:677b9713a120 872 debug("byte1 != 3\n");
nixnax 29:30de79d658f6 873 return;
nixnax 29:30de79d658f6 874 }
nixnax 29:30de79d658f6 875 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 64:677b9713a120 876 debug("byte2 != 21\n");
nixnax 29:30de79d658f6 877 return;
nixnax 29:30de79d658f6 878 }
nixnax 9:0992486d4a30 879 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 880 switch (packetType) {
nixnax 29:30de79d658f6 881 case 0xc0:
nixnax 29:30de79d658f6 882 LCPframe();
nixnax 29:30de79d658f6 883 break; // link control
nixnax 29:30de79d658f6 884 case 0x80:
nixnax 29:30de79d658f6 885 IPCPframe();
nixnax 29:30de79d658f6 886 break; // IP control
nixnax 29:30de79d658f6 887 case 0x00:
nixnax 29:30de79d658f6 888 IPframe();
nixnax 29:30de79d658f6 889 break; // IP itself
nixnax 29:30de79d658f6 890 default:
nixnax 29:30de79d658f6 891 discardedFrame();
nixnax 9:0992486d4a30 892 }
nixnax 29:30de79d658f6 893 }
nixnax 9:0992486d4a30 894
nixnax 50:ad4e7c3c88e5 895 void wait_for_HDLC_frame()
nixnax 50:ad4e7c3c88e5 896 {
nixnax 50:ad4e7c3c88e5 897 while ( rxbufNotEmpty() ) {
nixnax 50:ad4e7c3c88e5 898 int rx = pc_getBuf();
nixnax 50:ad4e7c3c88e5 899 if (ppp.hdlc.frameBusy) {
nixnax 50:ad4e7c3c88e5 900 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 901 if (ppp.rx.tail == 0) { // did we just wrap around?
nixnax 50:ad4e7c3c88e5 902 ppp.hdlc.frameEndIndex=BUFLEN-1; // wrap back to end of buffer
nixnax 51:a86d56844324 903 } else {
nixnax 50:ad4e7c3c88e5 904 ppp.hdlc.frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 50:ad4e7c3c88e5 905 }
nixnax 50:ad4e7c3c88e5 906 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex);
nixnax 75:0d513869231f 907 ppp.hdlc.frameStartIndex = ppp.rx.tail; // where next frame will start
nixnax 50:ad4e7c3c88e5 908 }
nixnax 50:ad4e7c3c88e5 909 } else {
nixnax 50:ad4e7c3c88e5 910 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 911 ppp.hdlc.frameBusy=1; // start gathering frame
nixnax 50:ad4e7c3c88e5 912 ppp.hdlc.frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 50:ad4e7c3c88e5 913 }
nixnax 50:ad4e7c3c88e5 914 }
nixnax 50:ad4e7c3c88e5 915 }
nixnax 50:ad4e7c3c88e5 916 }
nixnax 50:ad4e7c3c88e5 917
nixnax 29:30de79d658f6 918 void scanForConnectString()
nixnax 29:30de79d658f6 919 {
nixnax 9:0992486d4a30 920 if ( ppp.online==0 ) {
nixnax 71:965619fedb3a 921 // look for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
nixnax 77:abf92baebb42 922 char * clientFound = strstr( (char *)ppp.rx.buf, "CLIENTCLIENT" );
nixnax 29:30de79d658f6 923 if( clientFound ) {
nixnax 57:8deab70fef2e 924 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't find it again
nixnax 71:965619fedb3a 925 // respond with Windows Dialup networking expected "Direct Connection Between Two Computers" response string
nixnax 77:abf92baebb42 926 pc.printf("CLIENTSERVER");
nixnax 71:965619fedb3a 927 ppp.online=1; // we are connected, so stop looking for the string
nixnax 64:677b9713a120 928 debug("Connect string found\n");
nixnax 9:0992486d4a30 929 }
nixnax 9:0992486d4a30 930 }
nixnax 9:0992486d4a30 931 }
nixnax 9:0992486d4a30 932
nixnax 0:2cf4880c312a 933 int main()
nixnax 0:2cf4880c312a 934 {
nixnax 14:c65831c25aaa 935 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 936 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 49:2213f9c132b2 937 xx.baud(115200); // second serial port for debug messages
nixnax 9:0992486d4a30 938 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 939 #endif
nixnax 9:0992486d4a30 940 pppInitStruct(); // initialize all the PPP properties
nixnax 9:0992486d4a30 941 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 0:2cf4880c312a 942 while(1) {
nixnax 51:a86d56844324 943 scanForConnectString(); // respond to connect command from windows dial up networking
nixnax 50:ad4e7c3c88e5 944 wait_for_HDLC_frame();
nixnax 7:ab147f5e97ac 945 }
nixnax 7:ab147f5e97ac 946 }