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@56:b5b2e1c09f42, 2017-01-29 (annotated)

Committer:
nixnax
Date:
Sun Jan 29 23:07:53 2017 +0000
Revision:
56:b5b2e1c09f42
Parent:
55:43faae812be3
Child:
57:8deab70fef2e
Moved buffer read into critical section

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 44:d0c61ae49ea5 29 // The #define below enables/disables a second serial port that prints out interesting diagnostic messages.
nixnax 46:d73a565eaf7c 30 // change to SERIAL_PORT_MONITOR_YES to enable diagnistics messages. You will also need a second serial port.
nixnax 48:6352c1411c5f 31 #define SERIAL_PORT_MONITOR_NO /* or SERIAL_PORT_MONITOR_YES */
nixnax 0:2cf4880c312a 32
nixnax 41:e58a5a09f411 33 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 56:b5b2e1c09f42 34 Serial xx(PC_10, PC_11); // Not needed to run, if you get compile error here change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
nixnax 42:4de44be70bfd 35 #define debug(x...) xx.printf (x)
nixnax 41:e58a5a09f411 36 #else
nixnax 42:4de44be70bfd 37 #define debug(x...) {}
nixnax 41:e58a5a09f411 38 #endif
nixnax 41:e58a5a09f411 39
nixnax 51:a86d56844324 40 Serial pc(USBTX, USBRX); // The serial port on your mbed hardware. Your PC thinks this serial port is a dial-up modem.
nixnax 29:30de79d658f6 41
nixnax 29:30de79d658f6 42 int v0=1;
nixnax 29:30de79d658f6 43 int v1=1; // verbosity flags used in debug printouts - change to 1/0 to see more/less debug info
nixnax 29:30de79d658f6 44
nixnax 29:30de79d658f6 45 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 46
nixnax 29:30de79d658f6 47 // the standard hdlc frame start/end character
nixnax 4:a469050d5b80 48 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 49
nixnax 29:30de79d658f6 50 // the serial port receive buffer and packet buffer
nixnax 29:30de79d658f6 51 #define BUFLEN (1<<12)
nixnax 49:2213f9c132b2 52 char rxbufppp[BUFLEN]; // BUFLEN must be a power of two because we use & operator for fast wrap-around in rxHandler
nixnax 53:3a8a37fda757 53 char hdlcBuffer[2000]; // send/receive buffer for unstuffed (decoded) hdlc frame
nixnax 0:2cf4880c312a 54
nixnax 29:30de79d658f6 55 // a structure to keep all our ppp globals in
nixnax 50:ad4e7c3c88e5 56
nixnax 50:ad4e7c3c88e5 57
nixnax 29:30de79d658f6 58 struct pppType {
nixnax 38:ab582987926e 59 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 60 int ident; // our IP ident value
nixnax 38:ab582987926e 61 unsigned int seq; // our TCP sequence number
nixnax 38:ab582987926e 62 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 63 int ledState; // state of LED1
nixnax 4:a469050d5b80 64 struct {
nixnax 20:5db9b77b38a6 65 char * buf;
nixnax 29:30de79d658f6 66 volatile int head;
nixnax 29:30de79d658f6 67 volatile int tail;
nixnax 38:ab582987926e 68 } rx; // serial port objects
nixnax 4:a469050d5b80 69 struct {
nixnax 38:ab582987926e 70 int len; // number of bytes in buffer
nixnax 38:ab582987926e 71 int crc; // PPP CRC (frame check)
nixnax 38:ab582987926e 72 char * buf; // the actual buffer
nixnax 38:ab582987926e 73 } pkt; // ppp buffer objects
nixnax 50:ad4e7c3c88e5 74 struct {
nixnax 50:ad4e7c3c88e5 75 int frameStartIndex; // frame start marker
nixnax 50:ad4e7c3c88e5 76 int frameEndIndex; // frame end marker
nixnax 50:ad4e7c3c88e5 77 int frameBusy; // busy capturing a frame
nixnax 50:ad4e7c3c88e5 78 } hdlc; // hdlc frame objects
nixnax 29:30de79d658f6 79 };
nixnax 31:e000c1b9c565 80
nixnax 29:30de79d658f6 81 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 82
nixnax 29:30de79d658f6 83 // intitialize our globals
nixnax 29:30de79d658f6 84 void pppInitStruct()
nixnax 29:30de79d658f6 85 {
nixnax 29:30de79d658f6 86 ppp.online=0;
nixnax 49:2213f9c132b2 87 ppp.rx.buf=rxbufppp;
nixnax 29:30de79d658f6 88 ppp.rx.tail=0;
nixnax 29:30de79d658f6 89 ppp.rx.head=0;
nixnax 52:accc3026b2b0 90 ppp.pkt.buf=hdlcBuffer;
nixnax 29:30de79d658f6 91 ppp.pkt.len=0;
nixnax 29:30de79d658f6 92 ppp.ident=0;
nixnax 35:e7068df4d971 93 ppp.seq=1000;
nixnax 29:30de79d658f6 94 ppp.ledState=0;
nixnax 50:ad4e7c3c88e5 95 ppp.hdlc.frameBusy=0;
nixnax 29:30de79d658f6 96 }
nixnax 26:11f4eb2663a7 97
nixnax 43:aa57db08995d 98 void led1Toggle()
nixnax 43:aa57db08995d 99 {
nixnax 43:aa57db08995d 100 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 101 led1 = ppp.ledState;
nixnax 43:aa57db08995d 102 }
nixnax 43:aa57db08995d 103
nixnax 29:30de79d658f6 104 void crcReset()
nixnax 29:30de79d658f6 105 {
nixnax 29:30de79d658f6 106 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 107 }
nixnax 4:a469050d5b80 108
nixnax 29:30de79d658f6 109 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 110 {
nixnax 29:30de79d658f6 111 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 112 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 113 x>>=1;
nixnax 29:30de79d658f6 114 }
nixnax 29:30de79d658f6 115 }
nixnax 29:30de79d658f6 116
nixnax 29:30de79d658f6 117 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 118 {
nixnax 31:e000c1b9c565 119 crcReset();
nixnax 31:e000c1b9c565 120 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 121 return ppp.crc;
nixnax 29:30de79d658f6 122 }
nixnax 0:2cf4880c312a 123
nixnax 0:2cf4880c312a 124 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 125 {
nixnax 17:4918c893d802 126 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 127 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 128 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 129 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 130 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 131 }
nixnax 0:2cf4880c312a 132 }
nixnax 0:2cf4880c312a 133
nixnax 22:00df34cd4d7e 134 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 135 {
nixnax 22:00df34cd4d7e 136 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 137 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 138 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 139 return emptyStatus;
nixnax 0:2cf4880c312a 140 }
nixnax 0:2cf4880c312a 141
nixnax 0:2cf4880c312a 142 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 143 {
nixnax 22:00df34cd4d7e 144 if ( rxbufNotEmpty() ) {
nixnax 56:b5b2e1c09f42 145 __disable_irq(); // critical section start
nixnax 4:a469050d5b80 146 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 29:30de79d658f6 147 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 20:5db9b77b38a6 148 __enable_irq(); // critical section end
nixnax 0:2cf4880c312a 149 return x;
nixnax 20:5db9b77b38a6 150 } else return -1;
nixnax 0:2cf4880c312a 151 }
nixnax 0:2cf4880c312a 152
nixnax 50:ad4e7c3c88e5 153 void processHDLCFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 154 {
nixnax 38:ab582987926e 155 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 156 if(start==end) {
nixnax 29:30de79d658f6 157 pc.putc(0x7e);
nixnax 29:30de79d658f6 158 return;
nixnax 29:30de79d658f6 159 }
nixnax 9:0992486d4a30 160 crcReset();
nixnax 9:0992486d4a30 161 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 162 ppp.pkt.len=0;
nixnax 9:0992486d4a30 163 int unstuff=0;
nixnax 17:4918c893d802 164 int idx = start;
nixnax 17:4918c893d802 165 while(1) {
nixnax 9:0992486d4a30 166 if (unstuff==0) {
nixnax 49:2213f9c132b2 167 if (rxbufppp[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 168 else {
nixnax 49:2213f9c132b2 169 *dest = rxbufppp[idx];
nixnax 29:30de79d658f6 170 ppp.pkt.len++;
nixnax 29:30de79d658f6 171 dest++;
nixnax 49:2213f9c132b2 172 crcDo(rxbufppp[idx]);
nixnax 29:30de79d658f6 173 }
nixnax 12:db0dc91f0231 174 } else { // unstuff
nixnax 49:2213f9c132b2 175 *dest = rxbufppp[idx]^0x20;
nixnax 29:30de79d658f6 176 ppp.pkt.len++;
nixnax 29:30de79d658f6 177 dest++;
nixnax 49:2213f9c132b2 178 crcDo(rxbufppp[idx]^0x20);
nixnax 9:0992486d4a30 179 unstuff=0;
nixnax 9:0992486d4a30 180 }
nixnax 17:4918c893d802 181 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 182 if (idx == end) break;
nixnax 9:0992486d4a30 183 }
nixnax 29:30de79d658f6 184 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 185 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 186 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 187 determinePacketType();
nixnax 29:30de79d658f6 188 } else if (v0) {
nixnax 42:4de44be70bfd 189 debug("PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len);
nixnax 9:0992486d4a30 190 }
nixnax 9:0992486d4a30 191 }
nixnax 9:0992486d4a30 192
nixnax 38:ab582987926e 193 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 194 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 195 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 196 void dumpFrame()
nixnax 29:30de79d658f6 197 {
nixnax 42:4de44be70bfd 198 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 199 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 200 }
nixnax 16:cb0b80c24ba2 201
nixnax 29:30de79d658f6 202 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 203 {
nixnax 29:30de79d658f6 204 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 205 pc.putc(0x7d);
nixnax 38:ab582987926e 206 pc.putc(ch^0x20); // three characters need special handling
nixnax 29:30de79d658f6 207 } else {
nixnax 29:30de79d658f6 208 pc.putc(ch);
nixnax 29:30de79d658f6 209 }
nixnax 11:f58998c24f0b 210 }
nixnax 9:0992486d4a30 211
nixnax 38:ab582987926e 212 void sendFrame() // send one PPP frame in HDLC format
nixnax 29:30de79d658f6 213 {
nixnax 17:4918c893d802 214 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 215 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 216 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 217 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 218 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 219 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 220 }
nixnax 9:0992486d4a30 221
nixnax 29:30de79d658f6 222 void ipRequestHandler()
nixnax 29:30de79d658f6 223 {
nixnax 15:b0154c910143 224 debug(("IPCP Conf "));
nixnax 9:0992486d4a30 225 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 15:b0154c910143 226 debug(("Rej\n")); // reject if any options are requested
nixnax 9:0992486d4a30 227 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 228 sendFrame();
nixnax 9:0992486d4a30 229 } else {
nixnax 15:b0154c910143 230 debug(("Ack\n"));
nixnax 9:0992486d4a30 231 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 232 sendFrame(); // acknowledge
nixnax 29:30de79d658f6 233 debug(("IPCP Ask\n"));
nixnax 9:0992486d4a30 234 // send our own request now
nixnax 12:db0dc91f0231 235 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 236 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 237 sendFrame(); // this is our request
nixnax 9:0992486d4a30 238 }
nixnax 9:0992486d4a30 239 }
nixnax 9:0992486d4a30 240
nixnax 29:30de79d658f6 241 void ipAckHandler()
nixnax 29:30de79d658f6 242 {
nixnax 29:30de79d658f6 243 debug(("IPCP Grant\n"));
nixnax 29:30de79d658f6 244 }
nixnax 9:0992486d4a30 245
nixnax 29:30de79d658f6 246 void ipNackHandler()
nixnax 29:30de79d658f6 247 {
nixnax 29:30de79d658f6 248 debug(("IPCP Nack\n"));
nixnax 29:30de79d658f6 249 }
nixnax 9:0992486d4a30 250
nixnax 29:30de79d658f6 251 void ipDefaultHandler()
nixnax 29:30de79d658f6 252 {
nixnax 29:30de79d658f6 253 debug(("IPCP Other\n"));
nixnax 29:30de79d658f6 254 }
nixnax 29:30de79d658f6 255
nixnax 29:30de79d658f6 256 void IPCPframe()
nixnax 29:30de79d658f6 257 {
nixnax 9:0992486d4a30 258 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 259 switch (code) {
nixnax 29:30de79d658f6 260 case 1:
nixnax 29:30de79d658f6 261 ipRequestHandler();
nixnax 29:30de79d658f6 262 break;
nixnax 29:30de79d658f6 263 case 2:
nixnax 29:30de79d658f6 264 ipAckHandler();
nixnax 29:30de79d658f6 265 break;
nixnax 29:30de79d658f6 266 case 3:
nixnax 29:30de79d658f6 267 ipNackHandler();
nixnax 29:30de79d658f6 268 break;
nixnax 29:30de79d658f6 269 default:
nixnax 29:30de79d658f6 270 ipDefaultHandler();
nixnax 9:0992486d4a30 271 }
nixnax 29:30de79d658f6 272 }
nixnax 9:0992486d4a30 273
nixnax 29:30de79d658f6 274 void UDPpacket()
nixnax 29:30de79d658f6 275 {
nixnax 12:db0dc91f0231 276 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 277 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 278 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 55:43faae812be3 279 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 280 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 281 char * udpDst = udpBlock+2; // destination port
nixnax 55:43faae812be3 282 #endif
nixnax 12:db0dc91f0231 283 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 284 char * udpInf = udpBlock+8; // actual start of info
nixnax 55:43faae812be3 285 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 286 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 287 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 288 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 289 char * dstIP = udpPkt+16; // udp dst addr
nixnax 55:43faae812be3 290 #endif
nixnax 29:30de79d658f6 291 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 292 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 42:4de44be70bfd 293 if(v1) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 42:4de44be70bfd 294 if(v1) debug("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort);
nixnax 42:4de44be70bfd 295 debug("Len %d ", udpLength);
nixnax 29:30de79d658f6 296 int printSize = udpLength;
nixnax 29:30de79d658f6 297 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 298 if (v0) {
nixnax 29:30de79d658f6 299 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 300 char ch = udpInf[i];
nixnax 29:30de79d658f6 301 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 302 debug("%c", ch);
nixnax 29:30de79d658f6 303 } else {
nixnax 29:30de79d658f6 304 debug(("_"));
nixnax 29:30de79d658f6 305 }
nixnax 29:30de79d658f6 306 }
nixnax 29:30de79d658f6 307 debug(("\n"));
nixnax 29:30de79d658f6 308 }
nixnax 12:db0dc91f0231 309 }
nixnax 11:f58998c24f0b 310
nixnax 29:30de79d658f6 311 int dataCheckSum(char * ptr, int len)
nixnax 29:30de79d658f6 312 {
nixnax 29:30de79d658f6 313 int sum=0;
nixnax 29:30de79d658f6 314 int placeHolder;
nixnax 29:30de79d658f6 315 if (len&1) {
nixnax 38:ab582987926e 316 placeHolder = ptr[len-1]; // when length is odd stuff in a zero byte
nixnax 29:30de79d658f6 317 ptr[len-1]=0;
nixnax 29:30de79d658f6 318 }
nixnax 29:30de79d658f6 319 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 320 int hi = *ptr;
nixnax 29:30de79d658f6 321 ptr++;
nixnax 29:30de79d658f6 322 int lo = *ptr;
nixnax 29:30de79d658f6 323 ptr++;
nixnax 11:f58998c24f0b 324 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 325 sum = sum + val;
nixnax 11:f58998c24f0b 326 }
nixnax 11:f58998c24f0b 327 sum = sum + (sum>>16);
nixnax 29:30de79d658f6 328 if (len&1) {
nixnax 29:30de79d658f6 329 ptr[len-1] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 330 }
nixnax 12:db0dc91f0231 331 return ~sum;
nixnax 29:30de79d658f6 332 }
nixnax 11:f58998c24f0b 333
nixnax 29:30de79d658f6 334 void headerCheckSum()
nixnax 29:30de79d658f6 335 {
nixnax 11:f58998c24f0b 336 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 337 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 338 int sum=0;
nixnax 11:f58998c24f0b 339
nixnax 29:30de79d658f6 340 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 341 int hi = *ptr;
nixnax 29:30de79d658f6 342 ptr++;
nixnax 29:30de79d658f6 343 int lo = *ptr;
nixnax 29:30de79d658f6 344 ptr++;
nixnax 11:f58998c24f0b 345 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 346 sum = sum + val;
nixnax 11:f58998c24f0b 347 }
nixnax 11:f58998c24f0b 348 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 349 sum = ~sum;
nixnax 11:f58998c24f0b 350 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 351 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 352 }
nixnax 9:0992486d4a30 353
nixnax 29:30de79d658f6 354 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 355 {
nixnax 12:db0dc91f0231 356 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 357 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 358 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 359 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 360 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 361 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 362 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 363 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 364 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 365 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 366 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 367 char * dstAdr = ipPkt+16;
nixnax 55:43faae812be3 368 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 369 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 370 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 55:43faae812be3 371 #endif
nixnax 42:4de44be70bfd 372 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 373 debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 374 char src[4];
nixnax 29:30de79d658f6 375 char dst[4];
nixnax 12:db0dc91f0231 376 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 377 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 378 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 379 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 380 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 381 chkSum[0]=0;
nixnax 29:30de79d658f6 382 chkSum[1]=0;
nixnax 12:db0dc91f0231 383 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 384 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 385 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 386 icmpSum[0]=0;
nixnax 29:30de79d658f6 387 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 388 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 16:cb0b80c24ba2 389 int sum = dataCheckSum( icmpType, icmpLength); // this checksum on icmp data portion
nixnax 29:30de79d658f6 390 icmpSum[0]=sum>>8;
nixnax 29:30de79d658f6 391 icmpSum[1]=sum; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 392
nixnax 16:cb0b80c24ba2 393 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 394 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 395 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 396 if (v0) {
nixnax 29:30de79d658f6 397 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 398 char ch = icmpData[i];
nixnax 29:30de79d658f6 399 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 400 debug("%c",ch);
nixnax 29:30de79d658f6 401 } else {
nixnax 29:30de79d658f6 402 debug(("_"));
nixnax 29:30de79d658f6 403 }
nixnax 29:30de79d658f6 404 }
nixnax 29:30de79d658f6 405 debug(("\n"));
nixnax 29:30de79d658f6 406 }
nixnax 15:b0154c910143 407 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 408
nixnax 12:db0dc91f0231 409 } else {
nixnax 29:30de79d658f6 410 if (v0) {
nixnax 42:4de44be70bfd 411 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 412 }
nixnax 11:f58998c24f0b 413 }
nixnax 11:f58998c24f0b 414 }
nixnax 11:f58998c24f0b 415
nixnax 29:30de79d658f6 416 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 417 {
nixnax 29:30de79d658f6 418 if (v0) {
nixnax 42:4de44be70bfd 419 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 420 }
nixnax 29:30de79d658f6 421 }
nixnax 11:f58998c24f0b 422
nixnax 29:30de79d658f6 423 void dumpHeaderIP ()
nixnax 29:30de79d658f6 424 {
nixnax 26:11f4eb2663a7 425 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 55:43faae812be3 426 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 427 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 428 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 429 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 430 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 431 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 432 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 433 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 434 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 435 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 436 char * headercheck= ipPkt+10; // 2 bytes
nixnax 55:43faae812be3 437 #endif
nixnax 26:11f4eb2663a7 438 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 439 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 440
nixnax 55:43faae812be3 441 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 442 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 443 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 444 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 445 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 446 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 447 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 448 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 449 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 450 int protocolIP = protocol[0];
nixnax 55:43faae812be3 451 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 452 #endif
nixnax 55:43faae812be3 453
nixnax 29:30de79d658f6 454 char srcIP [16];
nixnax 29:30de79d658f6 455 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 456 char dstIP [16];
nixnax 29:30de79d658f6 457 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 42:4de44be70bfd 458 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 459 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 460 }
nixnax 26:11f4eb2663a7 461
nixnax 29:30de79d658f6 462 void dumpHeaderTCP()
nixnax 29:30de79d658f6 463 {
nixnax 29:30de79d658f6 464 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 465 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 55:43faae812be3 466 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 467 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 468 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 55:43faae812be3 469 #endif
nixnax 29:30de79d658f6 470 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 55:43faae812be3 471 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 31:e000c1b9c565 472 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 473 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 55:43faae812be3 474 #endif
nixnax 26:11f4eb2663a7 475 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 476
nixnax 29:30de79d658f6 477 char flagInfo[10];
nixnax 29:30de79d658f6 478 memset(flagInfo,'.',10); // text presentation of TCP flags
nixnax 29:30de79d658f6 479 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 480 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 481 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 482 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 483 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 484 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 485 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 486 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 487 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 29:30de79d658f6 488 flagInfo[9]=0; // null terminate string
nixnax 29:30de79d658f6 489 if (v0) {
nixnax 42:4de44be70bfd 490 debug("Flags %s Seq %u Ack %u", flagInfo, seq, ack);
nixnax 29:30de79d658f6 491 }
nixnax 29:30de79d658f6 492 }
nixnax 29:30de79d658f6 493
nixnax 29:30de79d658f6 494 void tcpHandler()
nixnax 29:30de79d658f6 495 {
nixnax 26:11f4eb2663a7 496 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 497 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 498 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 499 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 500 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 501 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 502 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 503 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 504 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 505 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 506
nixnax 29:30de79d658f6 507 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 508 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 509
nixnax 29:30de79d658f6 510 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 511 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 512 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 513 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 514 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 515 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 516 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 517 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 518
nixnax 26:11f4eb2663a7 519 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 520 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 29:30de79d658f6 521
nixnax 31:e000c1b9c565 522 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 523 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 29:30de79d658f6 524
nixnax 35:e7068df4d971 525 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 526
nixnax 35:e7068df4d971 527 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 35:e7068df4d971 528 int incomingLen = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 28:1aa629be05e7 529
nixnax 29:30de79d658f6 530 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 531 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 532 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 533 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 534 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 535
nixnax 38:ab582987926e 536 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 38:ab582987926e 537 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 38:ab582987926e 538 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 29:30de79d658f6 539
nixnax 35:e7068df4d971 540 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 541 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 542 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 543
nixnax 38:ab582987926e 544 if (ppp.seq != ack) {
nixnax 38:ab582987926e 545 ppp.seq = ack; // if their sequence number is different than our calculation we adopt their version
nixnax 38:ab582987926e 546 }
nixnax 35:e7068df4d971 547
nixnax 35:e7068df4d971 548 if ( ((flagsTCP & ~TCP_FLAG_ACK) == 0) && ((flagsTCP & TCP_FLAG_ACK) != 0) ) {
nixnax 38:ab582987926e 549 if (incomingLen == 0) { // ignore - just an empty ack packet
nixnax 38:ab582987926e 550 return;
nixnax 38:ab582987926e 551 }
nixnax 38:ab582987926e 552 } else if ( (flagsTCP & TCP_FLAG_SYN) != 0 ) { // got SYN flag
nixnax 36:2a9b457f8276 553 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // do a syn-ack
nixnax 38:ab582987926e 554 seq++; // for SYN flag we have to increase sequence by 1
nixnax 38:ab582987926e 555 } else if ( (flagsTCP & TCP_FLAG_FIN) != 0 ) { // got FIN flag
nixnax 38:ab582987926e 556 seq++; // for FIN flag we have to increase sequence by 1
nixnax 38:ab582987926e 557 } else if ( (flagsTCP & TCP_FLAG_PSH) != 0 ) { // got PSH flag (push)
nixnax 38:ab582987926e 558 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 38:ab582987926e 559 fastResponse = 1; // we can respond fast to a push
nixnax 38:ab582987926e 560 // It's a push, so let's check the incoming data for an HTTP GET request
nixnax 31:e000c1b9c565 561 if ( strncmp(dataStart, "GET / HTTP/1.1", 14) == 0) {
nixnax 44:d0c61ae49ea5 562 dataLen = 32*32; // this block has to hold the web page below, but keep it under 1024 or increase this
nixnax 38:ab582987926e 563 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 50:ad4e7c3c88e5 564
nixnax 38:ab582987926e 565 int n=0; // number of bytes we have printed so far
nixnax 31:e000c1b9c565 566 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 44:d0c61ae49ea5 567 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 44:d0c61ae49ea5 568 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 44:d0c61ae49ea5 569 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 44:d0c61ae49ea5 570 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header must end with empty line (\r\n)
nixnax 47:00a5ca075f8f 571 int nHeader=n; // byte total of all headers. Note - seems like this must be 1+(multiple of four)
nixnax 44:d0c61ae49ea5 572
nixnax 44:d0c61ae49ea5 573 n=n+sprintf(n+dataStart,"<!DOCTYPE html>\n<html><head><title>mbed-PPP-Blinky</title>\n<script>window.onload=function()"); // html start
nixnax 44:d0c61ae49ea5 574 n=n+sprintf(n+dataStart,"{setInterval(function(){function x(){return document.getElementById('w');};\n"); // html
nixnax 50:ad4e7c3c88e5 575 n=n+sprintf(n+dataStart,"x().textContent = parseInt(x().textContent)+1;},100);};</script></head>\n"); // html
nixnax 46:d73a565eaf7c 576 n=n+sprintf(n+dataStart,"<body style=\"font-family: sans-serif; font-size:30px; color:#807070\">"); // html
nixnax 44:d0c61ae49ea5 577 n=n+sprintf(n+dataStart,"<h1>mbed PPP-Blinky Up and Running</h1>\n<h1 id=\"w\" style=\"text-align:"); // html
nixnax 47:00a5ca075f8f 578 n=n+sprintf(n+dataStart," center;\">0</h1><h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\n</body></html>\r\n"); // html end
nixnax 50:ad4e7c3c88e5 579
nixnax 44:d0c61ae49ea5 580 int contentLength = n-nHeader; // Content-Length is the count of every character after the header
nixnax 44:d0c61ae49ea5 581 int cSize = 5; // maximum number of digits we allow for Content-Length
nixnax 44:d0c61ae49ea5 582 char contentLengthString[cSize+1]; // temporary buffer to create Content-Length string
nixnax 44:d0c61ae49ea5 583 snprintf(contentLengthString,cSize+1,"%*d",cSize,contentLength); // print Content-Length with leading spaces and fixed width = csize
nixnax 44:d0c61ae49ea5 584 memcpy(dataStart+contentLengthStart, contentLengthString, cSize); // copy Content-Length to the send buffer
nixnax 50:ad4e7c3c88e5 585
nixnax 31:e000c1b9c565 586 if (v0) {
nixnax 44:d0c61ae49ea5 587 debug("HTTP GET BufferSize %d*32=%d Header %d Content-Length %d Total %d Available %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n);
nixnax 31:e000c1b9c565 588 }
nixnax 44:d0c61ae49ea5 589 dataLen=n; // update the buffer size
nixnax 38:ab582987926e 590 } else if ( strncmp(dataStart, "GET /", 4) == 0) { // all other HTTP GET requests get 404 Not Found response
nixnax 44:d0c61ae49ea5 591 dataLen = 32*32; // maximum size for File not found webpage
nixnax 38:ab582987926e 592 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 50:ad4e7c3c88e5 593
nixnax 38:ab582987926e 594 int n=0; // number of bytes we have printed so far
nixnax 41:e58a5a09f411 595 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 44:d0c61ae49ea5 596 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 44:d0c61ae49ea5 597 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 44:d0c61ae49ea5 598 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 47:00a5ca075f8f 599 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header must end with empty line (\r\n)
nixnax 47:00a5ca075f8f 600 int nHeader=n; // byte total of all headers. Note - seems like this must be 1+(multiple of four)
nixnax 44:d0c61ae49ea5 601
nixnax 44:d0c61ae49ea5 602 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head></head>"); // html start
nixnax 44:d0c61ae49ea5 603 n=n+sprintf(n+dataStart,"<body><h1>File Not Found</h1></body>");
nixnax 47:00a5ca075f8f 604 n=n+sprintf(n+dataStart,"</html>\r\n"); // html end
nixnax 44:d0c61ae49ea5 605
nixnax 44:d0c61ae49ea5 606 int contentLength = n-nHeader; // Content-Length is the count of every character after the header
nixnax 44:d0c61ae49ea5 607 int cSize = 5; // maximum number of digits we allow for Content-Length
nixnax 44:d0c61ae49ea5 608 char contentLengthString[cSize+1]; // temporary buffer to create Content-Length string
nixnax 44:d0c61ae49ea5 609 snprintf(contentLengthString,cSize+1,"%*d",cSize,contentLength); // print Content-Length with leading spaces and fixed width = csize
nixnax 44:d0c61ae49ea5 610 memcpy(dataStart+contentLengthStart, contentLengthString, cSize); // copy Content-Length to the send buffer
nixnax 44:d0c61ae49ea5 611
nixnax 31:e000c1b9c565 612 if (v0) {
nixnax 44:d0c61ae49ea5 613 debug("HTTP GET BufSize %d*32=%d Header %d Content-Length %d Total %d Available %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n);
nixnax 31:e000c1b9c565 614 }
nixnax 44:d0c61ae49ea5 615 dataLen=n; // update the buffer size
nixnax 35:e7068df4d971 616 } else {
nixnax 38:ab582987926e 617 dataLen=0; // we did not find a valid HTTP request, so just ACK with zero data
nixnax 29:30de79d658f6 618 }
nixnax 36:2a9b457f8276 619 } else {
nixnax 38:ab582987926e 620 dataLen=0; // it's not any TCP Flag Combo that needs special handling
nixnax 28:1aa629be05e7 621 }
nixnax 29:30de79d658f6 622
nixnax 38:ab582987926e 623 // All the TCP flag handling is now done
nixnax 29:30de79d658f6 624
nixnax 38:ab582987926e 625 // 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 626
nixnax 38:ab582987926e 627 char src[4]; // temp hold
nixnax 38:ab582987926e 628 char dst[4]; // temp hold
nixnax 29:30de79d658f6 629 memcpy(src, srcAdr,4);
nixnax 29:30de79d658f6 630 memcpy(dst, dstAdr,4);
nixnax 29:30de79d658f6 631 memcpy(srcAdr, dst,4);
nixnax 29:30de79d658f6 632 memcpy(dstAdr, src,4); // swap ip address source/dest
nixnax 38:ab582987926e 633
nixnax 38:ab582987926e 634 char psrc[2]; // temp hold
nixnax 38:ab582987926e 635 char pdst[2]; // temp hold
nixnax 29:30de79d658f6 636 memcpy(psrc, srctcp,2);
nixnax 29:30de79d658f6 637 memcpy(pdst, dsttcp,2);
nixnax 29:30de79d658f6 638 memcpy(srctcp, pdst,2);
nixnax 29:30de79d658f6 639 memcpy(dsttcp, psrc,2); // swap ip port source/dest
nixnax 29:30de79d658f6 640
nixnax 38:ab582987926e 641 ack = seq + incomingLen; // acknowledge the number of bytes that they sent by adding it to "our" sequence number
nixnax 38:ab582987926e 642 seq = ppp.seq; // set up the sequence number we have to respond with
nixnax 38:ab582987926e 643
nixnax 38:ab582987926e 644 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 645 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 646 acktcp[2]=ack>>8;
nixnax 38:ab582987926e 647 acktcp[3]=ack>>0; // save ack
nixnax 38:ab582987926e 648
nixnax 38:ab582987926e 649 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 650 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 651 seqtcp[2]=seq>>8;
nixnax 38:ab582987926e 652 seqtcp[3]=seq>>0; // save seq
nixnax 38:ab582987926e 653
nixnax 38:ab582987926e 654 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 655
nixnax 38:ab582987926e 656 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 657 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 658 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 659 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 660 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 661
nixnax 38:ab582987926e 662 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 663
nixnax 29:30de79d658f6 664 headercheck[0]=0;
nixnax 29:30de79d658f6 665 headercheck[1]=0;
nixnax 29:30de79d658f6 666 headerCheckSum(); // redo the ip header checksum
nixnax 38:ab582987926e 667
nixnax 38:ab582987926e 668 char pseudoHeader[12]; // we are building a fake TCP header
nixnax 29:30de79d658f6 669 int sum;
nixnax 26:11f4eb2663a7 670 memcpy( pseudoHeader+0, srcAdr, 8); // source and destination addresses.
nixnax 29:30de79d658f6 671 pseudoHeader[8]=0;
nixnax 29:30de79d658f6 672 pseudoHeader[9]=protocol[0];
nixnax 29:30de79d658f6 673 pseudoHeader[10]=tcpSize>>8;
nixnax 29:30de79d658f6 674 pseudoHeader[11]=tcpSize;
nixnax 38:ab582987926e 675 char temp[12]; // temporary storage for the 12 bytes that are in the way
nixnax 38:ab582987926e 676 memcpy(temp, s-12, 12); // save the 12 bytes that are in the way
nixnax 38:ab582987926e 677 memcpy( s-12, pseudoHeader, 12); // copy in the fake header
nixnax 29:30de79d658f6 678 checksumtcp[0]=0;
nixnax 29:30de79d658f6 679 checksumtcp[1]=0;
nixnax 38:ab582987926e 680 sum=dataCheckSum(s-12,tcpSize+12); // calculate the TCP checksum
nixnax 29:30de79d658f6 681 checksumtcp[0]=sum>>8;
nixnax 29:30de79d658f6 682 checksumtcp[1]=sum;
nixnax 38:ab582987926e 683 memcpy( s-12, temp, 12); // restore the 12 bytes that the fake header overwrote
nixnax 36:2a9b457f8276 684 if (fastResponse==1) {
nixnax 36:2a9b457f8276 685 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 686 } else {
nixnax 38:ab582987926e 687 wait(0.2); // normally, you wait 200 ms before sending a TCP packet
nixnax 36:2a9b457f8276 688 }
nixnax 38:ab582987926e 689 sendFrame(); // All done! Send the TCP packet
nixnax 38:ab582987926e 690 ppp.seq = ppp.seq + dataLen; // increase OUR sequence by the outgoing data length - for the next round
nixnax 29:30de79d658f6 691 }
nixnax 26:11f4eb2663a7 692
nixnax 29:30de79d658f6 693 void dumpDataTCP()
nixnax 29:30de79d658f6 694 {
nixnax 26:11f4eb2663a7 695 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 696 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 697 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 698 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 699 if (v1) {
nixnax 42:4de44be70bfd 700 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 701 }
nixnax 29:30de79d658f6 702 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 703 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 704 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 705 }
nixnax 29:30de79d658f6 706 }
nixnax 26:11f4eb2663a7 707
nixnax 29:30de79d658f6 708 void TCPpacket()
nixnax 29:30de79d658f6 709 {
nixnax 26:11f4eb2663a7 710 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 55:43faae812be3 711 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 712 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 713 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 714 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 715 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 716 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 717 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 718 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 719 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 720 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 721 char * headercheck= ipPkt+10; // 2 bytes
nixnax 55:43faae812be3 722 #endif
nixnax 26:11f4eb2663a7 723 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 724 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 725
nixnax 55:43faae812be3 726 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 727 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 728 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 729 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 730 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 731 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 732 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 733 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 734 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 735 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 736 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 737 #endif
nixnax 29:30de79d658f6 738 char srcIP [16];
nixnax 29:30de79d658f6 739 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 740 char dstIP [16];
nixnax 29:30de79d658f6 741 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 742 if (v0) {
nixnax 42:4de44be70bfd 743 debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 29:30de79d658f6 744 }
nixnax 29:30de79d658f6 745 if (v0) {
nixnax 42:4de44be70bfd 746 debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 747 }
nixnax 28:1aa629be05e7 748 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 749 dumpDataTCP();
nixnax 26:11f4eb2663a7 750 tcpHandler();
nixnax 11:f58998c24f0b 751 }
nixnax 11:f58998c24f0b 752
nixnax 29:30de79d658f6 753 void otherProtocol()
nixnax 29:30de79d658f6 754 {
nixnax 29:30de79d658f6 755 debug(("Other IP protocol"));
nixnax 29:30de79d658f6 756 }
nixnax 26:11f4eb2663a7 757
nixnax 29:30de79d658f6 758 void IPframe()
nixnax 29:30de79d658f6 759 {
nixnax 10:74f8233f72c0 760 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 761 switch (protocol) {
nixnax 29:30de79d658f6 762 case 1:
nixnax 29:30de79d658f6 763 ICMPpacket();
nixnax 29:30de79d658f6 764 break;
nixnax 29:30de79d658f6 765 case 2:
nixnax 29:30de79d658f6 766 IGMPpacket();
nixnax 29:30de79d658f6 767 break;
nixnax 29:30de79d658f6 768 case 17:
nixnax 29:30de79d658f6 769 UDPpacket();
nixnax 29:30de79d658f6 770 break;
nixnax 29:30de79d658f6 771 case 6:
nixnax 29:30de79d658f6 772 TCPpacket();
nixnax 29:30de79d658f6 773 break;
nixnax 29:30de79d658f6 774 default:
nixnax 29:30de79d658f6 775 otherProtocol();
nixnax 29:30de79d658f6 776 }
nixnax 29:30de79d658f6 777 }
nixnax 9:0992486d4a30 778
nixnax 29:30de79d658f6 779 void LCPconfReq()
nixnax 29:30de79d658f6 780 {
nixnax 15:b0154c910143 781 debug(("LCP Config "));
nixnax 9:0992486d4a30 782 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 783 ppp.pkt.buf[4]=4; // allow only no options
nixnax 15:b0154c910143 784 debug(("Reject\n"));
nixnax 29:30de79d658f6 785 sendFrame();
nixnax 9:0992486d4a30 786 } else {
nixnax 9:0992486d4a30 787 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 15:b0154c910143 788 debug(("Ack\n"));
nixnax 9:0992486d4a30 789 sendFrame();
nixnax 15:b0154c910143 790 debug(("LCP Ask\n"));
nixnax 11:f58998c24f0b 791 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 792 sendFrame();
nixnax 9:0992486d4a30 793 }
nixnax 9:0992486d4a30 794 }
nixnax 9:0992486d4a30 795
nixnax 29:30de79d658f6 796 void LCPconfAck()
nixnax 29:30de79d658f6 797 {
nixnax 15:b0154c910143 798 debug(("LCP Ack\n"));
nixnax 29:30de79d658f6 799 }
nixnax 9:0992486d4a30 800
nixnax 29:30de79d658f6 801 void LCPend()
nixnax 29:30de79d658f6 802 {
nixnax 29:30de79d658f6 803 debug(("LCP End\n"));
nixnax 29:30de79d658f6 804 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 805 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 806 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 807 }
nixnax 9:0992486d4a30 808
nixnax 29:30de79d658f6 809 void LCPother()
nixnax 29:30de79d658f6 810 {
nixnax 29:30de79d658f6 811 debug(("LCP Other\n"));
nixnax 29:30de79d658f6 812 dumpFrame();
nixnax 29:30de79d658f6 813 }
nixnax 29:30de79d658f6 814
nixnax 29:30de79d658f6 815 void LCPframe()
nixnax 29:30de79d658f6 816 {
nixnax 29:30de79d658f6 817 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 818 switch (code) {
nixnax 29:30de79d658f6 819 case 1:
nixnax 29:30de79d658f6 820 LCPconfReq();
nixnax 29:30de79d658f6 821 break; // config request
nixnax 29:30de79d658f6 822 case 2:
nixnax 29:30de79d658f6 823 LCPconfAck();
nixnax 29:30de79d658f6 824 break; // config ack
nixnax 29:30de79d658f6 825 case 5:
nixnax 29:30de79d658f6 826 LCPend();
nixnax 29:30de79d658f6 827 break; // end connection
nixnax 29:30de79d658f6 828 default:
nixnax 29:30de79d658f6 829 LCPother();
nixnax 29:30de79d658f6 830 }
nixnax 9:0992486d4a30 831 }
nixnax 9:0992486d4a30 832
nixnax 29:30de79d658f6 833 void discardedFrame()
nixnax 29:30de79d658f6 834 {
nixnax 29:30de79d658f6 835 if (v0) {
nixnax 42:4de44be70bfd 836 debug("Dropping frame %02x %02x %02x %02x\n", ppp.pkt.buf[0],ppp.pkt.buf[1],ppp.pkt.buf[2],ppp.pkt.buf[3]);
nixnax 29:30de79d658f6 837 }
nixnax 9:0992486d4a30 838 }
nixnax 9:0992486d4a30 839
nixnax 29:30de79d658f6 840 void determinePacketType()
nixnax 29:30de79d658f6 841 {
nixnax 29:30de79d658f6 842 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 29:30de79d658f6 843 debug(("byte0 != ff\n"));
nixnax 29:30de79d658f6 844 return;
nixnax 29:30de79d658f6 845 }
nixnax 29:30de79d658f6 846 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 29:30de79d658f6 847 debug(("byte1 != 3\n"));
nixnax 29:30de79d658f6 848 return;
nixnax 29:30de79d658f6 849 }
nixnax 29:30de79d658f6 850 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 29:30de79d658f6 851 debug(("byte2 != 21\n"));
nixnax 29:30de79d658f6 852 return;
nixnax 29:30de79d658f6 853 }
nixnax 9:0992486d4a30 854 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 855 switch (packetType) {
nixnax 29:30de79d658f6 856 case 0xc0:
nixnax 29:30de79d658f6 857 LCPframe();
nixnax 29:30de79d658f6 858 break; // link control
nixnax 29:30de79d658f6 859 case 0x80:
nixnax 29:30de79d658f6 860 IPCPframe();
nixnax 29:30de79d658f6 861 break; // IP control
nixnax 29:30de79d658f6 862 case 0x00:
nixnax 29:30de79d658f6 863 IPframe();
nixnax 29:30de79d658f6 864 break; // IP itself
nixnax 29:30de79d658f6 865 default:
nixnax 29:30de79d658f6 866 discardedFrame();
nixnax 9:0992486d4a30 867 }
nixnax 29:30de79d658f6 868 }
nixnax 9:0992486d4a30 869
nixnax 50:ad4e7c3c88e5 870 void wait_for_HDLC_frame()
nixnax 50:ad4e7c3c88e5 871 {
nixnax 50:ad4e7c3c88e5 872
nixnax 50:ad4e7c3c88e5 873 while ( rxbufNotEmpty() ) {
nixnax 50:ad4e7c3c88e5 874 int rx = pc_getBuf();
nixnax 50:ad4e7c3c88e5 875 if (ppp.hdlc.frameBusy) {
nixnax 50:ad4e7c3c88e5 876 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 877 ppp.hdlc.frameBusy=0; // done gathering frame
nixnax 50:ad4e7c3c88e5 878 if (ppp.rx.tail == 0) { // did we just wrap around?
nixnax 50:ad4e7c3c88e5 879 ppp.hdlc.frameEndIndex=BUFLEN-1; // wrap back to end of buffer
nixnax 51:a86d56844324 880 } else {
nixnax 50:ad4e7c3c88e5 881 ppp.hdlc.frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 50:ad4e7c3c88e5 882 }
nixnax 50:ad4e7c3c88e5 883 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex);
nixnax 50:ad4e7c3c88e5 884 }
nixnax 50:ad4e7c3c88e5 885 } else {
nixnax 50:ad4e7c3c88e5 886 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 887 ppp.hdlc.frameBusy=1; // start gathering frame
nixnax 50:ad4e7c3c88e5 888 ppp.hdlc.frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 50:ad4e7c3c88e5 889 }
nixnax 50:ad4e7c3c88e5 890 }
nixnax 50:ad4e7c3c88e5 891 }
nixnax 50:ad4e7c3c88e5 892 }
nixnax 50:ad4e7c3c88e5 893
nixnax 29:30de79d658f6 894 void scanForConnectString()
nixnax 29:30de79d658f6 895 {
nixnax 9:0992486d4a30 896 if ( ppp.online==0 ) {
nixnax 49:2213f9c132b2 897 char * clientFound = strstr( (char *)rxbufppp, "CLIENTCLIENT" ); // look for PC string
nixnax 29:30de79d658f6 898 if( clientFound ) {
nixnax 9:0992486d4a30 899 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't get fixated
nixnax 9:0992486d4a30 900 pc.printf("CLIENTSERVER"); // respond to PC
nixnax 9:0992486d4a30 901 ppp.online=1; // we can stop looking for the string
nixnax 15:b0154c910143 902 debug(("Connect string found\n"));
nixnax 9:0992486d4a30 903 }
nixnax 9:0992486d4a30 904 }
nixnax 9:0992486d4a30 905 }
nixnax 9:0992486d4a30 906
nixnax 0:2cf4880c312a 907 int main()
nixnax 0:2cf4880c312a 908 {
nixnax 14:c65831c25aaa 909 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 910 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 49:2213f9c132b2 911 xx.baud(115200); // second serial port for debug messages
nixnax 9:0992486d4a30 912 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 913 #endif
nixnax 9:0992486d4a30 914 pppInitStruct(); // initialize all the PPP properties
nixnax 9:0992486d4a30 915 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 0:2cf4880c312a 916 while(1) {
nixnax 51:a86d56844324 917 scanForConnectString(); // respond to connect command from windows dial up networking
nixnax 50:ad4e7c3c88e5 918 wait_for_HDLC_frame();
nixnax 7:ab147f5e97ac 919 }
nixnax 7:ab147f5e97ac 920 }