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@60:2b770949c911, 2017-06-04 (annotated)

Committer:
nixnax
Date:
Sun Jun 04 18:18:29 2017 +0000
Revision:
60:2b770949c911
Parent:
58:8f39f28f9b14
Child:
62:f192926e42f1
Buffer consolidation

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 60:2b770949c911 83 // Initialize 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 56:b5b2e1c09f42 144 __disable_irq(); // critical section start
nixnax 4:a469050d5b80 145 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 29:30de79d658f6 146 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 20:5db9b77b38a6 147 __enable_irq(); // critical section end
nixnax 0:2cf4880c312a 148 return x;
nixnax 0:2cf4880c312a 149 }
nixnax 0:2cf4880c312a 150
nixnax 50:ad4e7c3c88e5 151 void processHDLCFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 152 {
nixnax 38:ab582987926e 153 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 154 if(start==end) {
nixnax 29:30de79d658f6 155 pc.putc(0x7e);
nixnax 29:30de79d658f6 156 return;
nixnax 29:30de79d658f6 157 }
nixnax 9:0992486d4a30 158 crcReset();
nixnax 9:0992486d4a30 159 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 160 ppp.pkt.len=0;
nixnax 9:0992486d4a30 161 int unstuff=0;
nixnax 17:4918c893d802 162 int idx = start;
nixnax 17:4918c893d802 163 while(1) {
nixnax 9:0992486d4a30 164 if (unstuff==0) {
nixnax 49:2213f9c132b2 165 if (rxbufppp[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 166 else {
nixnax 49:2213f9c132b2 167 *dest = rxbufppp[idx];
nixnax 29:30de79d658f6 168 ppp.pkt.len++;
nixnax 29:30de79d658f6 169 dest++;
nixnax 49:2213f9c132b2 170 crcDo(rxbufppp[idx]);
nixnax 29:30de79d658f6 171 }
nixnax 12:db0dc91f0231 172 } else { // unstuff
nixnax 49:2213f9c132b2 173 *dest = rxbufppp[idx]^0x20;
nixnax 29:30de79d658f6 174 ppp.pkt.len++;
nixnax 29:30de79d658f6 175 dest++;
nixnax 49:2213f9c132b2 176 crcDo(rxbufppp[idx]^0x20);
nixnax 9:0992486d4a30 177 unstuff=0;
nixnax 9:0992486d4a30 178 }
nixnax 17:4918c893d802 179 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 180 if (idx == end) break;
nixnax 9:0992486d4a30 181 }
nixnax 29:30de79d658f6 182 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 183 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 184 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 185 determinePacketType();
nixnax 29:30de79d658f6 186 } else if (v0) {
nixnax 42:4de44be70bfd 187 debug("PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len);
nixnax 9:0992486d4a30 188 }
nixnax 9:0992486d4a30 189 }
nixnax 9:0992486d4a30 190
nixnax 38:ab582987926e 191 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 192 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 193 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 194 void dumpFrame()
nixnax 29:30de79d658f6 195 {
nixnax 42:4de44be70bfd 196 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 197 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 198 }
nixnax 16:cb0b80c24ba2 199
nixnax 29:30de79d658f6 200 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 201 {
nixnax 29:30de79d658f6 202 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 203 pc.putc(0x7d);
nixnax 38:ab582987926e 204 pc.putc(ch^0x20); // three characters need special handling
nixnax 29:30de79d658f6 205 } else {
nixnax 29:30de79d658f6 206 pc.putc(ch);
nixnax 29:30de79d658f6 207 }
nixnax 11:f58998c24f0b 208 }
nixnax 9:0992486d4a30 209
nixnax 38:ab582987926e 210 void sendFrame() // send one PPP frame in HDLC format
nixnax 29:30de79d658f6 211 {
nixnax 17:4918c893d802 212 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 213 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 214 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 215 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 216 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 217 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 218 }
nixnax 9:0992486d4a30 219
nixnax 29:30de79d658f6 220 void ipRequestHandler()
nixnax 29:30de79d658f6 221 {
nixnax 15:b0154c910143 222 debug(("IPCP Conf "));
nixnax 9:0992486d4a30 223 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 15:b0154c910143 224 debug(("Rej\n")); // reject if any options are requested
nixnax 9:0992486d4a30 225 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 226 sendFrame();
nixnax 9:0992486d4a30 227 } else {
nixnax 15:b0154c910143 228 debug(("Ack\n"));
nixnax 9:0992486d4a30 229 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 230 sendFrame(); // acknowledge
nixnax 29:30de79d658f6 231 debug(("IPCP Ask\n"));
nixnax 9:0992486d4a30 232 // send our own request now
nixnax 12:db0dc91f0231 233 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 234 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 235 sendFrame(); // this is our request
nixnax 9:0992486d4a30 236 }
nixnax 9:0992486d4a30 237 }
nixnax 9:0992486d4a30 238
nixnax 29:30de79d658f6 239 void ipAckHandler()
nixnax 29:30de79d658f6 240 {
nixnax 29:30de79d658f6 241 debug(("IPCP Grant\n"));
nixnax 29:30de79d658f6 242 }
nixnax 9:0992486d4a30 243
nixnax 29:30de79d658f6 244 void ipNackHandler()
nixnax 29:30de79d658f6 245 {
nixnax 29:30de79d658f6 246 debug(("IPCP Nack\n"));
nixnax 29:30de79d658f6 247 }
nixnax 9:0992486d4a30 248
nixnax 29:30de79d658f6 249 void ipDefaultHandler()
nixnax 29:30de79d658f6 250 {
nixnax 29:30de79d658f6 251 debug(("IPCP Other\n"));
nixnax 29:30de79d658f6 252 }
nixnax 29:30de79d658f6 253
nixnax 29:30de79d658f6 254 void IPCPframe()
nixnax 29:30de79d658f6 255 {
nixnax 9:0992486d4a30 256 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 257 switch (code) {
nixnax 29:30de79d658f6 258 case 1:
nixnax 29:30de79d658f6 259 ipRequestHandler();
nixnax 29:30de79d658f6 260 break;
nixnax 29:30de79d658f6 261 case 2:
nixnax 29:30de79d658f6 262 ipAckHandler();
nixnax 29:30de79d658f6 263 break;
nixnax 29:30de79d658f6 264 case 3:
nixnax 29:30de79d658f6 265 ipNackHandler();
nixnax 29:30de79d658f6 266 break;
nixnax 29:30de79d658f6 267 default:
nixnax 29:30de79d658f6 268 ipDefaultHandler();
nixnax 9:0992486d4a30 269 }
nixnax 29:30de79d658f6 270 }
nixnax 9:0992486d4a30 271
nixnax 29:30de79d658f6 272 void UDPpacket()
nixnax 29:30de79d658f6 273 {
nixnax 12:db0dc91f0231 274 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 275 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 276 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 55:43faae812be3 277 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 12:db0dc91f0231 278 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 279 char * udpDst = udpBlock+2; // destination port
nixnax 55:43faae812be3 280 #endif
nixnax 12:db0dc91f0231 281 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 282 char * udpInf = udpBlock+8; // actual start of info
nixnax 55:43faae812be3 283 #ifndef SERIAL_PORT_MONITOR_NO
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 55:43faae812be3 288 #endif
nixnax 29:30de79d658f6 289 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 290 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 42:4de44be70bfd 291 if(v1) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 42:4de44be70bfd 292 if(v1) debug("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort);
nixnax 42:4de44be70bfd 293 debug("Len %d ", udpLength);
nixnax 29:30de79d658f6 294 int printSize = udpLength;
nixnax 29:30de79d658f6 295 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 296 if (v0) {
nixnax 29:30de79d658f6 297 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 298 char ch = udpInf[i];
nixnax 29:30de79d658f6 299 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 300 debug("%c", ch);
nixnax 29:30de79d658f6 301 } else {
nixnax 29:30de79d658f6 302 debug(("_"));
nixnax 29:30de79d658f6 303 }
nixnax 29:30de79d658f6 304 }
nixnax 29:30de79d658f6 305 debug(("\n"));
nixnax 29:30de79d658f6 306 }
nixnax 12:db0dc91f0231 307 }
nixnax 11:f58998c24f0b 308
nixnax 29:30de79d658f6 309 int dataCheckSum(char * ptr, int len)
nixnax 29:30de79d658f6 310 {
nixnax 29:30de79d658f6 311 int sum=0;
nixnax 29:30de79d658f6 312 int placeHolder;
nixnax 29:30de79d658f6 313 if (len&1) {
nixnax 38:ab582987926e 314 placeHolder = ptr[len-1]; // when length is odd stuff in a zero byte
nixnax 29:30de79d658f6 315 ptr[len-1]=0;
nixnax 29:30de79d658f6 316 }
nixnax 29:30de79d658f6 317 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 318 int hi = *ptr;
nixnax 29:30de79d658f6 319 ptr++;
nixnax 29:30de79d658f6 320 int lo = *ptr;
nixnax 29:30de79d658f6 321 ptr++;
nixnax 11:f58998c24f0b 322 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 323 sum = sum + val;
nixnax 11:f58998c24f0b 324 }
nixnax 11:f58998c24f0b 325 sum = sum + (sum>>16);
nixnax 29:30de79d658f6 326 if (len&1) {
nixnax 29:30de79d658f6 327 ptr[len-1] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 328 }
nixnax 12:db0dc91f0231 329 return ~sum;
nixnax 29:30de79d658f6 330 }
nixnax 11:f58998c24f0b 331
nixnax 29:30de79d658f6 332 void headerCheckSum()
nixnax 29:30de79d658f6 333 {
nixnax 11:f58998c24f0b 334 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 335 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 336 int sum=0;
nixnax 11:f58998c24f0b 337
nixnax 29:30de79d658f6 338 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 339 int hi = *ptr;
nixnax 29:30de79d658f6 340 ptr++;
nixnax 29:30de79d658f6 341 int lo = *ptr;
nixnax 29:30de79d658f6 342 ptr++;
nixnax 11:f58998c24f0b 343 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 344 sum = sum + val;
nixnax 11:f58998c24f0b 345 }
nixnax 11:f58998c24f0b 346 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 347 sum = ~sum;
nixnax 11:f58998c24f0b 348 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 349 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 350 }
nixnax 9:0992486d4a30 351
nixnax 29:30de79d658f6 352 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 353 {
nixnax 12:db0dc91f0231 354 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 355 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 356 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 357 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 358 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 359 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 360 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 361 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 362 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 363 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 364 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 365 char * dstAdr = ipPkt+16;
nixnax 55:43faae812be3 366 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 18:3e35de1bc877 367 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 368 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 55:43faae812be3 369 #endif
nixnax 42:4de44be70bfd 370 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 371 debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 372 char src[4];
nixnax 29:30de79d658f6 373 char dst[4];
nixnax 12:db0dc91f0231 374 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 375 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 376 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 377 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 378 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 379 chkSum[0]=0;
nixnax 29:30de79d658f6 380 chkSum[1]=0;
nixnax 12:db0dc91f0231 381 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 382 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 383 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 384 icmpSum[0]=0;
nixnax 29:30de79d658f6 385 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 386 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 16:cb0b80c24ba2 387 int sum = dataCheckSum( icmpType, icmpLength); // this checksum on icmp data portion
nixnax 29:30de79d658f6 388 icmpSum[0]=sum>>8;
nixnax 29:30de79d658f6 389 icmpSum[1]=sum; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 390
nixnax 16:cb0b80c24ba2 391 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 392 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 393 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 394 if (v0) {
nixnax 29:30de79d658f6 395 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 396 char ch = icmpData[i];
nixnax 29:30de79d658f6 397 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 398 debug("%c",ch);
nixnax 29:30de79d658f6 399 } else {
nixnax 29:30de79d658f6 400 debug(("_"));
nixnax 29:30de79d658f6 401 }
nixnax 29:30de79d658f6 402 }
nixnax 29:30de79d658f6 403 debug(("\n"));
nixnax 29:30de79d658f6 404 }
nixnax 15:b0154c910143 405 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 406
nixnax 12:db0dc91f0231 407 } else {
nixnax 29:30de79d658f6 408 if (v0) {
nixnax 42:4de44be70bfd 409 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 410 }
nixnax 11:f58998c24f0b 411 }
nixnax 11:f58998c24f0b 412 }
nixnax 11:f58998c24f0b 413
nixnax 29:30de79d658f6 414 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 415 {
nixnax 29:30de79d658f6 416 if (v0) {
nixnax 42:4de44be70bfd 417 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 418 }
nixnax 29:30de79d658f6 419 }
nixnax 11:f58998c24f0b 420
nixnax 29:30de79d658f6 421 void dumpHeaderIP ()
nixnax 29:30de79d658f6 422 {
nixnax 26:11f4eb2663a7 423 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 55:43faae812be3 424 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 425 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 426 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 427 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 428 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 429 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 430 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 431 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 432 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 433 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 434 char * headercheck= ipPkt+10; // 2 bytes
nixnax 55:43faae812be3 435 #endif
nixnax 26:11f4eb2663a7 436 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 437 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 438
nixnax 55:43faae812be3 439 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 440 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 441 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 442 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 443 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 444 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 445 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 446 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 447 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 448 int protocolIP = protocol[0];
nixnax 55:43faae812be3 449 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 450 #endif
nixnax 55:43faae812be3 451
nixnax 29:30de79d658f6 452 char srcIP [16];
nixnax 29:30de79d658f6 453 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 454 char dstIP [16];
nixnax 29:30de79d658f6 455 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 42:4de44be70bfd 456 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 457 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 458 }
nixnax 26:11f4eb2663a7 459
nixnax 29:30de79d658f6 460 void dumpHeaderTCP()
nixnax 29:30de79d658f6 461 {
nixnax 29:30de79d658f6 462 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 463 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 55:43faae812be3 464 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 465 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 466 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 55:43faae812be3 467 #endif
nixnax 29:30de79d658f6 468 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 55:43faae812be3 469 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 31:e000c1b9c565 470 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 471 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 55:43faae812be3 472 #endif
nixnax 26:11f4eb2663a7 473 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 474
nixnax 29:30de79d658f6 475 char flagInfo[10];
nixnax 29:30de79d658f6 476 memset(flagInfo,'.',10); // text presentation of TCP flags
nixnax 29:30de79d658f6 477 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 478 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 479 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 480 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 481 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 482 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 483 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 484 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 485 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 29:30de79d658f6 486 flagInfo[9]=0; // null terminate string
nixnax 29:30de79d658f6 487 if (v0) {
nixnax 42:4de44be70bfd 488 debug("Flags %s Seq %u Ack %u", flagInfo, seq, ack);
nixnax 29:30de79d658f6 489 }
nixnax 29:30de79d658f6 490 }
nixnax 29:30de79d658f6 491
nixnax 29:30de79d658f6 492 void tcpHandler()
nixnax 29:30de79d658f6 493 {
nixnax 26:11f4eb2663a7 494 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 495 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 496 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 497 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 498 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 499 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 500 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 501 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 502 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 503 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 504
nixnax 29:30de79d658f6 505 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 506 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 507
nixnax 29:30de79d658f6 508 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 509 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 510 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 511 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 512 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 513 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 514 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 515 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 516
nixnax 26:11f4eb2663a7 517 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 518 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 29:30de79d658f6 519
nixnax 31:e000c1b9c565 520 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 521 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 29:30de79d658f6 522
nixnax 35:e7068df4d971 523 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 524
nixnax 35:e7068df4d971 525 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 35:e7068df4d971 526 int incomingLen = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 28:1aa629be05e7 527
nixnax 29:30de79d658f6 528 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 529 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 530 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 531 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 532 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 533
nixnax 38:ab582987926e 534 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 38:ab582987926e 535 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 38:ab582987926e 536 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 29:30de79d658f6 537
nixnax 35:e7068df4d971 538 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 539 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 540 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 541
nixnax 58:8f39f28f9b14 542 ppp.seq = ack; // adopt their sequence number calculation in place of doing our own calculation
nixnax 35:e7068df4d971 543
nixnax 35:e7068df4d971 544 if ( ((flagsTCP & ~TCP_FLAG_ACK) == 0) && ((flagsTCP & TCP_FLAG_ACK) != 0) ) {
nixnax 38:ab582987926e 545 if (incomingLen == 0) { // ignore - just an empty ack packet
nixnax 38:ab582987926e 546 return;
nixnax 38:ab582987926e 547 }
nixnax 38:ab582987926e 548 } else if ( (flagsTCP & TCP_FLAG_SYN) != 0 ) { // got SYN flag
nixnax 36:2a9b457f8276 549 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // do a syn-ack
nixnax 38:ab582987926e 550 seq++; // for SYN flag we have to increase sequence by 1
nixnax 38:ab582987926e 551 } else if ( (flagsTCP & TCP_FLAG_FIN) != 0 ) { // got FIN flag
nixnax 38:ab582987926e 552 seq++; // for FIN flag we have to increase sequence by 1
nixnax 38:ab582987926e 553 } else if ( (flagsTCP & TCP_FLAG_PSH) != 0 ) { // got PSH flag (push)
nixnax 38:ab582987926e 554 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 38:ab582987926e 555 fastResponse = 1; // we can respond fast to a push
nixnax 38:ab582987926e 556 // It's a push, so let's check the incoming data for an HTTP GET request
nixnax 31:e000c1b9c565 557 if ( strncmp(dataStart, "GET / HTTP/1.1", 14) == 0) {
nixnax 44:d0c61ae49ea5 558 dataLen = 32*32; // this block has to hold the web page below, but keep it under 1024 or increase this
nixnax 38:ab582987926e 559 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 50:ad4e7c3c88e5 560
nixnax 38:ab582987926e 561 int n=0; // number of bytes we have printed so far
nixnax 31:e000c1b9c565 562 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 44:d0c61ae49ea5 563 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 44:d0c61ae49ea5 564 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 44:d0c61ae49ea5 565 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 44:d0c61ae49ea5 566 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 567 int nHeader=n; // byte total of all headers. Note - seems like this must be 1+(multiple of four)
nixnax 44:d0c61ae49ea5 568
nixnax 44:d0c61ae49ea5 569 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 570 n=n+sprintf(n+dataStart,"{setInterval(function(){function x(){return document.getElementById('w');};\n"); // html
nixnax 50:ad4e7c3c88e5 571 n=n+sprintf(n+dataStart,"x().textContent = parseInt(x().textContent)+1;},100);};</script></head>\n"); // html
nixnax 46:d73a565eaf7c 572 n=n+sprintf(n+dataStart,"<body style=\"font-family: sans-serif; font-size:30px; color:#807070\">"); // html
nixnax 44:d0c61ae49ea5 573 n=n+sprintf(n+dataStart,"<h1>mbed PPP-Blinky Up and Running</h1>\n<h1 id=\"w\" style=\"text-align:"); // html
nixnax 47:00a5ca075f8f 574 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 575
nixnax 44:d0c61ae49ea5 576 int contentLength = n-nHeader; // Content-Length is the count of every character after the header
nixnax 44:d0c61ae49ea5 577 int cSize = 5; // maximum number of digits we allow for Content-Length
nixnax 44:d0c61ae49ea5 578 char contentLengthString[cSize+1]; // temporary buffer to create Content-Length string
nixnax 44:d0c61ae49ea5 579 snprintf(contentLengthString,cSize+1,"%*d",cSize,contentLength); // print Content-Length with leading spaces and fixed width = csize
nixnax 44:d0c61ae49ea5 580 memcpy(dataStart+contentLengthStart, contentLengthString, cSize); // copy Content-Length to the send buffer
nixnax 50:ad4e7c3c88e5 581
nixnax 31:e000c1b9c565 582 if (v0) {
nixnax 44:d0c61ae49ea5 583 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 584 }
nixnax 44:d0c61ae49ea5 585 dataLen=n; // update the buffer size
nixnax 38:ab582987926e 586 } else if ( strncmp(dataStart, "GET /", 4) == 0) { // all other HTTP GET requests get 404 Not Found response
nixnax 44:d0c61ae49ea5 587 dataLen = 32*32; // maximum size for File not found webpage
nixnax 38:ab582987926e 588 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 50:ad4e7c3c88e5 589
nixnax 38:ab582987926e 590 int n=0; // number of bytes we have printed so far
nixnax 41:e58a5a09f411 591 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 44:d0c61ae49ea5 592 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 44:d0c61ae49ea5 593 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 44:d0c61ae49ea5 594 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 47:00a5ca075f8f 595 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 596 int nHeader=n; // byte total of all headers. Note - seems like this must be 1+(multiple of four)
nixnax 44:d0c61ae49ea5 597
nixnax 44:d0c61ae49ea5 598 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head></head>"); // html start
nixnax 44:d0c61ae49ea5 599 n=n+sprintf(n+dataStart,"<body><h1>File Not Found</h1></body>");
nixnax 47:00a5ca075f8f 600 n=n+sprintf(n+dataStart,"</html>\r\n"); // html end
nixnax 44:d0c61ae49ea5 601
nixnax 44:d0c61ae49ea5 602 int contentLength = n-nHeader; // Content-Length is the count of every character after the header
nixnax 44:d0c61ae49ea5 603 int cSize = 5; // maximum number of digits we allow for Content-Length
nixnax 44:d0c61ae49ea5 604 char contentLengthString[cSize+1]; // temporary buffer to create Content-Length string
nixnax 44:d0c61ae49ea5 605 snprintf(contentLengthString,cSize+1,"%*d",cSize,contentLength); // print Content-Length with leading spaces and fixed width = csize
nixnax 44:d0c61ae49ea5 606 memcpy(dataStart+contentLengthStart, contentLengthString, cSize); // copy Content-Length to the send buffer
nixnax 44:d0c61ae49ea5 607
nixnax 31:e000c1b9c565 608 if (v0) {
nixnax 44:d0c61ae49ea5 609 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 610 }
nixnax 44:d0c61ae49ea5 611 dataLen=n; // update the buffer size
nixnax 35:e7068df4d971 612 } else {
nixnax 38:ab582987926e 613 dataLen=0; // we did not find a valid HTTP request, so just ACK with zero data
nixnax 29:30de79d658f6 614 }
nixnax 36:2a9b457f8276 615 } else {
nixnax 38:ab582987926e 616 dataLen=0; // it's not any TCP Flag Combo that needs special handling
nixnax 28:1aa629be05e7 617 }
nixnax 29:30de79d658f6 618
nixnax 38:ab582987926e 619 // All the TCP flag handling is now done
nixnax 29:30de79d658f6 620
nixnax 38:ab582987926e 621 // 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 622
nixnax 60:2b770949c911 623 char tempHold[12]; // a temporary hold buffer
nixnax 38:ab582987926e 624
nixnax 60:2b770949c911 625 memcpy(tempHold, srcAdr,4);
nixnax 60:2b770949c911 626 memcpy(tempHold+4, dstAdr,4);
nixnax 60:2b770949c911 627 memcpy(srcAdr, tempHold+4,4);
nixnax 60:2b770949c911 628 memcpy(dstAdr, tempHold,4); // swap ip address source/dest
nixnax 60:2b770949c911 629
nixnax 60:2b770949c911 630 memcpy(tempHold, srctcp,2);
nixnax 60:2b770949c911 631 memcpy(tempHold+2, dsttcp,2);
nixnax 60:2b770949c911 632 memcpy(srctcp, tempHold+2,2);
nixnax 60:2b770949c911 633 memcpy(dsttcp, tempHold,2); // swap ip port source/dest
nixnax 29:30de79d658f6 634
nixnax 38:ab582987926e 635 ack = seq + incomingLen; // acknowledge the number of bytes that they sent by adding it to "our" sequence number
nixnax 38:ab582987926e 636 seq = ppp.seq; // set up the sequence number we have to respond with
nixnax 38:ab582987926e 637
nixnax 38:ab582987926e 638 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 639 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 640 acktcp[2]=ack>>8;
nixnax 38:ab582987926e 641 acktcp[3]=ack>>0; // save ack
nixnax 38:ab582987926e 642
nixnax 38:ab582987926e 643 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 644 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 645 seqtcp[2]=seq>>8;
nixnax 38:ab582987926e 646 seqtcp[3]=seq>>0; // save seq
nixnax 38:ab582987926e 647
nixnax 38:ab582987926e 648 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 649
nixnax 38:ab582987926e 650 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 651 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 652 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 653 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 654 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 655
nixnax 38:ab582987926e 656 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 657
nixnax 29:30de79d658f6 658 headercheck[0]=0;
nixnax 29:30de79d658f6 659 headercheck[1]=0;
nixnax 29:30de79d658f6 660 headerCheckSum(); // redo the ip header checksum
nixnax 60:2b770949c911 661
nixnax 60:2b770949c911 662 // now we have to build a 12-byte TCP pseudo-header in front of the TCP packet in order to calculate the correct TCP checksum
nixnax 60:2b770949c911 663
nixnax 60:2b770949c911 664 memcpy(tempHold, s-12, 12); // preserve the 12 bytes in the IP header that are in the way of the pseudo-header
nixnax 60:2b770949c911 665
nixnax 60:2b770949c911 666 memcpy( s-12, srcAdr, 8); // source and destination addresses.
nixnax 60:2b770949c911 667 memset( s-4, 0, 1); // reserved - must be set to zero
nixnax 60:2b770949c911 668 memset( s-3, protocol[0], 1); // protocol field from the IP header
nixnax 60:2b770949c911 669 memset( s-2, tcpSize>>8, 1); // length of TCP header
nixnax 60:2b770949c911 670 memset( s-1, tcpSize, 1); // length of TCP header
nixnax 38:ab582987926e 671
nixnax 60:2b770949c911 672 checksumtcp[0]=0; // has to be zero for fake header calculation
nixnax 60:2b770949c911 673 checksumtcp[1]=0; // has to be zero for fake header calculation
nixnax 60:2b770949c911 674
nixnax 60:2b770949c911 675 int sum=dataCheckSum(s-12,tcpSize+12); // calculate the TCP checksum starting at the fake 12-byte header
nixnax 29:30de79d658f6 676 checksumtcp[0]=sum>>8;
nixnax 29:30de79d658f6 677 checksumtcp[1]=sum;
nixnax 60:2b770949c911 678 memcpy( s-12, tempHold, 12); // restore the 12 bytes that the fake header overwrote
nixnax 36:2a9b457f8276 679 if (fastResponse==1) {
nixnax 36:2a9b457f8276 680 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 681 } else {
nixnax 38:ab582987926e 682 wait(0.2); // normally, you wait 200 ms before sending a TCP packet
nixnax 36:2a9b457f8276 683 }
nixnax 38:ab582987926e 684 sendFrame(); // All done! Send the TCP packet
nixnax 38:ab582987926e 685 ppp.seq = ppp.seq + dataLen; // increase OUR sequence by the outgoing data length - for the next round
nixnax 29:30de79d658f6 686 }
nixnax 26:11f4eb2663a7 687
nixnax 29:30de79d658f6 688 void dumpDataTCP()
nixnax 29:30de79d658f6 689 {
nixnax 26:11f4eb2663a7 690 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 691 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 692 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 693 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 694 if (v1) {
nixnax 42:4de44be70bfd 695 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 696 }
nixnax 29:30de79d658f6 697 if (dataLen > 0) {
nixnax 47:00a5ca075f8f 698 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 699 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 700 }
nixnax 29:30de79d658f6 701 }
nixnax 26:11f4eb2663a7 702
nixnax 29:30de79d658f6 703 void TCPpacket()
nixnax 29:30de79d658f6 704 {
nixnax 26:11f4eb2663a7 705 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 55:43faae812be3 706 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 26:11f4eb2663a7 707 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 708 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 709 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 710 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 711 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 712 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 713 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 714 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 715 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 716 char * headercheck= ipPkt+10; // 2 bytes
nixnax 55:43faae812be3 717 #endif
nixnax 26:11f4eb2663a7 718 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 719 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 720
nixnax 55:43faae812be3 721 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 29:30de79d658f6 722 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 723 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 724 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 725 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 726 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 727 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 728 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 729 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 730 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 731 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 55:43faae812be3 732 #endif
nixnax 29:30de79d658f6 733 char srcIP [16];
nixnax 29:30de79d658f6 734 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 735 char dstIP [16];
nixnax 29:30de79d658f6 736 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 737 if (v0) {
nixnax 42:4de44be70bfd 738 debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 29:30de79d658f6 739 }
nixnax 29:30de79d658f6 740 if (v0) {
nixnax 42:4de44be70bfd 741 debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 742 }
nixnax 28:1aa629be05e7 743 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 744 dumpDataTCP();
nixnax 26:11f4eb2663a7 745 tcpHandler();
nixnax 11:f58998c24f0b 746 }
nixnax 11:f58998c24f0b 747
nixnax 29:30de79d658f6 748 void otherProtocol()
nixnax 29:30de79d658f6 749 {
nixnax 29:30de79d658f6 750 debug(("Other IP protocol"));
nixnax 29:30de79d658f6 751 }
nixnax 26:11f4eb2663a7 752
nixnax 29:30de79d658f6 753 void IPframe()
nixnax 29:30de79d658f6 754 {
nixnax 10:74f8233f72c0 755 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 756 switch (protocol) {
nixnax 29:30de79d658f6 757 case 1:
nixnax 29:30de79d658f6 758 ICMPpacket();
nixnax 29:30de79d658f6 759 break;
nixnax 29:30de79d658f6 760 case 2:
nixnax 29:30de79d658f6 761 IGMPpacket();
nixnax 29:30de79d658f6 762 break;
nixnax 29:30de79d658f6 763 case 17:
nixnax 29:30de79d658f6 764 UDPpacket();
nixnax 29:30de79d658f6 765 break;
nixnax 29:30de79d658f6 766 case 6:
nixnax 29:30de79d658f6 767 TCPpacket();
nixnax 29:30de79d658f6 768 break;
nixnax 29:30de79d658f6 769 default:
nixnax 29:30de79d658f6 770 otherProtocol();
nixnax 29:30de79d658f6 771 }
nixnax 29:30de79d658f6 772 }
nixnax 9:0992486d4a30 773
nixnax 29:30de79d658f6 774 void LCPconfReq()
nixnax 29:30de79d658f6 775 {
nixnax 15:b0154c910143 776 debug(("LCP Config "));
nixnax 9:0992486d4a30 777 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 778 ppp.pkt.buf[4]=4; // allow only no options
nixnax 15:b0154c910143 779 debug(("Reject\n"));
nixnax 29:30de79d658f6 780 sendFrame();
nixnax 9:0992486d4a30 781 } else {
nixnax 9:0992486d4a30 782 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 15:b0154c910143 783 debug(("Ack\n"));
nixnax 9:0992486d4a30 784 sendFrame();
nixnax 15:b0154c910143 785 debug(("LCP Ask\n"));
nixnax 11:f58998c24f0b 786 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 787 sendFrame();
nixnax 9:0992486d4a30 788 }
nixnax 9:0992486d4a30 789 }
nixnax 9:0992486d4a30 790
nixnax 29:30de79d658f6 791 void LCPconfAck()
nixnax 29:30de79d658f6 792 {
nixnax 15:b0154c910143 793 debug(("LCP Ack\n"));
nixnax 29:30de79d658f6 794 }
nixnax 9:0992486d4a30 795
nixnax 29:30de79d658f6 796 void LCPend()
nixnax 29:30de79d658f6 797 {
nixnax 29:30de79d658f6 798 debug(("LCP End\n"));
nixnax 29:30de79d658f6 799 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 800 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 801 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 802 }
nixnax 9:0992486d4a30 803
nixnax 29:30de79d658f6 804 void LCPother()
nixnax 29:30de79d658f6 805 {
nixnax 29:30de79d658f6 806 debug(("LCP Other\n"));
nixnax 29:30de79d658f6 807 dumpFrame();
nixnax 29:30de79d658f6 808 }
nixnax 29:30de79d658f6 809
nixnax 29:30de79d658f6 810 void LCPframe()
nixnax 29:30de79d658f6 811 {
nixnax 29:30de79d658f6 812 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 813 switch (code) {
nixnax 29:30de79d658f6 814 case 1:
nixnax 29:30de79d658f6 815 LCPconfReq();
nixnax 29:30de79d658f6 816 break; // config request
nixnax 29:30de79d658f6 817 case 2:
nixnax 29:30de79d658f6 818 LCPconfAck();
nixnax 29:30de79d658f6 819 break; // config ack
nixnax 29:30de79d658f6 820 case 5:
nixnax 29:30de79d658f6 821 LCPend();
nixnax 29:30de79d658f6 822 break; // end connection
nixnax 29:30de79d658f6 823 default:
nixnax 29:30de79d658f6 824 LCPother();
nixnax 29:30de79d658f6 825 }
nixnax 9:0992486d4a30 826 }
nixnax 9:0992486d4a30 827
nixnax 29:30de79d658f6 828 void discardedFrame()
nixnax 29:30de79d658f6 829 {
nixnax 29:30de79d658f6 830 if (v0) {
nixnax 42:4de44be70bfd 831 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 832 }
nixnax 9:0992486d4a30 833 }
nixnax 9:0992486d4a30 834
nixnax 29:30de79d658f6 835 void determinePacketType()
nixnax 29:30de79d658f6 836 {
nixnax 29:30de79d658f6 837 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 29:30de79d658f6 838 debug(("byte0 != ff\n"));
nixnax 29:30de79d658f6 839 return;
nixnax 29:30de79d658f6 840 }
nixnax 29:30de79d658f6 841 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 29:30de79d658f6 842 debug(("byte1 != 3\n"));
nixnax 29:30de79d658f6 843 return;
nixnax 29:30de79d658f6 844 }
nixnax 29:30de79d658f6 845 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 29:30de79d658f6 846 debug(("byte2 != 21\n"));
nixnax 29:30de79d658f6 847 return;
nixnax 29:30de79d658f6 848 }
nixnax 9:0992486d4a30 849 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 850 switch (packetType) {
nixnax 29:30de79d658f6 851 case 0xc0:
nixnax 29:30de79d658f6 852 LCPframe();
nixnax 29:30de79d658f6 853 break; // link control
nixnax 29:30de79d658f6 854 case 0x80:
nixnax 29:30de79d658f6 855 IPCPframe();
nixnax 29:30de79d658f6 856 break; // IP control
nixnax 29:30de79d658f6 857 case 0x00:
nixnax 29:30de79d658f6 858 IPframe();
nixnax 29:30de79d658f6 859 break; // IP itself
nixnax 29:30de79d658f6 860 default:
nixnax 29:30de79d658f6 861 discardedFrame();
nixnax 9:0992486d4a30 862 }
nixnax 29:30de79d658f6 863 }
nixnax 9:0992486d4a30 864
nixnax 50:ad4e7c3c88e5 865 void wait_for_HDLC_frame()
nixnax 50:ad4e7c3c88e5 866 {
nixnax 50:ad4e7c3c88e5 867 while ( rxbufNotEmpty() ) {
nixnax 50:ad4e7c3c88e5 868 int rx = pc_getBuf();
nixnax 50:ad4e7c3c88e5 869 if (ppp.hdlc.frameBusy) {
nixnax 50:ad4e7c3c88e5 870 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 871 ppp.hdlc.frameBusy=0; // done gathering frame
nixnax 50:ad4e7c3c88e5 872 if (ppp.rx.tail == 0) { // did we just wrap around?
nixnax 50:ad4e7c3c88e5 873 ppp.hdlc.frameEndIndex=BUFLEN-1; // wrap back to end of buffer
nixnax 51:a86d56844324 874 } else {
nixnax 50:ad4e7c3c88e5 875 ppp.hdlc.frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 50:ad4e7c3c88e5 876 }
nixnax 50:ad4e7c3c88e5 877 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex);
nixnax 50:ad4e7c3c88e5 878 }
nixnax 50:ad4e7c3c88e5 879 } else {
nixnax 50:ad4e7c3c88e5 880 if (rx==FRAME_7E) {
nixnax 50:ad4e7c3c88e5 881 ppp.hdlc.frameBusy=1; // start gathering frame
nixnax 50:ad4e7c3c88e5 882 ppp.hdlc.frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 50:ad4e7c3c88e5 883 }
nixnax 50:ad4e7c3c88e5 884 }
nixnax 50:ad4e7c3c88e5 885 }
nixnax 50:ad4e7c3c88e5 886 }
nixnax 50:ad4e7c3c88e5 887
nixnax 29:30de79d658f6 888 void scanForConnectString()
nixnax 29:30de79d658f6 889 {
nixnax 9:0992486d4a30 890 if ( ppp.online==0 ) {
nixnax 49:2213f9c132b2 891 char * clientFound = strstr( (char *)rxbufppp, "CLIENTCLIENT" ); // look for PC string
nixnax 29:30de79d658f6 892 if( clientFound ) {
nixnax 57:8deab70fef2e 893 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't find it again
nixnax 9:0992486d4a30 894 pc.printf("CLIENTSERVER"); // respond to PC
nixnax 9:0992486d4a30 895 ppp.online=1; // we can stop looking for the string
nixnax 15:b0154c910143 896 debug(("Connect string found\n"));
nixnax 9:0992486d4a30 897 }
nixnax 9:0992486d4a30 898 }
nixnax 9:0992486d4a30 899 }
nixnax 9:0992486d4a30 900
nixnax 0:2cf4880c312a 901 int main()
nixnax 0:2cf4880c312a 902 {
nixnax 14:c65831c25aaa 903 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 904 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 49:2213f9c132b2 905 xx.baud(115200); // second serial port for debug messages
nixnax 9:0992486d4a30 906 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 907 #endif
nixnax 9:0992486d4a30 908 pppInitStruct(); // initialize all the PPP properties
nixnax 9:0992486d4a30 909 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 0:2cf4880c312a 910 while(1) {
nixnax 51:a86d56844324 911 scanForConnectString(); // respond to connect command from windows dial up networking
nixnax 50:ad4e7c3c88e5 912 wait_for_HDLC_frame();
nixnax 7:ab147f5e97ac 913 }
nixnax 7:ab147f5e97ac 914 }