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@50:ad4e7c3c88e5, 2017-01-29 (annotated)

Committer:
nixnax
Date:
Sun Jan 29 00:58:03 2017 +0000
Revision:
50:ad4e7c3c88e5
Parent:
49:2213f9c132b2
Child:
51:a86d56844324
Child:
52:accc3026b2b0
Fixed HDLC frameEndIndex wraparound bug; Moved wait_for_HDLC_Frame code to a function

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