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@43:aa57db08995d, 2017-01-17 (annotated)

Committer:
nixnax
Date:
Tue Jan 17 21:08:03 2017 +0000
Revision:
43:aa57db08995d
Parent:
42:4de44be70bfd
Child:
44:d0c61ae49ea5
Small Fiddles

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 41:e58a5a09f411 20 // https://ttssh2.osdn.jp/index.html.en - Tera Term, agood terminal program to monitor the debug output from the second serial port with!
nixnax 29:30de79d658f6 21 // Wireshark - can't monitor Dial-Up network packets on windows, but very hand - 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 41:e58a5a09f411 29 // This #define enables/disables a second serial port that prints out interesting diagnostic messages
nixnax 41:e58a5a09f411 30 #define SERIAL_PORT_MONITOR_YES
nixnax 41:e58a5a09f411 31 // #define SERIAL_PORT_MONITOR_NO
nixnax 0:2cf4880c312a 32
nixnax 41:e58a5a09f411 33 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 41:e58a5a09f411 34 Serial xx(PC_10, PC_11); // See debug messages on this port. Not necessary to work, but VERY interesting output!
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 20:5db9b77b38a6 53 char rxbuf[BUFLEN];
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 29:30de79d658f6 57 struct pppType {
nixnax 38:ab582987926e 58 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 59 int ident; // our IP ident value
nixnax 38:ab582987926e 60 unsigned int seq; // our TCP sequence number
nixnax 38:ab582987926e 61 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 62 int ledState; // state of LED1
nixnax 4:a469050d5b80 63 struct {
nixnax 20:5db9b77b38a6 64 char * buf;
nixnax 29:30de79d658f6 65 volatile int head;
nixnax 29:30de79d658f6 66 volatile int tail;
nixnax 38:ab582987926e 67 } rx; // serial port objects
nixnax 4:a469050d5b80 68 struct {
nixnax 38:ab582987926e 69 int len; // number of bytes in buffer
nixnax 38:ab582987926e 70 int crc; // PPP CRC (frame check)
nixnax 38:ab582987926e 71 char * buf; // the actual buffer
nixnax 38:ab582987926e 72 } pkt; // ppp buffer objects
nixnax 29:30de79d658f6 73 };
nixnax 31:e000c1b9c565 74
nixnax 29:30de79d658f6 75 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 76
nixnax 29:30de79d658f6 77 // intitialize our globals
nixnax 29:30de79d658f6 78 void pppInitStruct()
nixnax 29:30de79d658f6 79 {
nixnax 29:30de79d658f6 80 ppp.online=0;
nixnax 29:30de79d658f6 81 ppp.rx.buf=rxbuf;
nixnax 29:30de79d658f6 82 ppp.rx.tail=0;
nixnax 29:30de79d658f6 83 ppp.rx.head=0;
nixnax 29:30de79d658f6 84 ppp.pkt.buf=frbuf;
nixnax 29:30de79d658f6 85 ppp.pkt.len=0;
nixnax 29:30de79d658f6 86 ppp.ident=0;
nixnax 35:e7068df4d971 87 ppp.seq=1000;
nixnax 29:30de79d658f6 88 ppp.ledState=0;
nixnax 29:30de79d658f6 89 }
nixnax 26:11f4eb2663a7 90
nixnax 43:aa57db08995d 91 void led1Toggle()
nixnax 43:aa57db08995d 92 {
nixnax 43:aa57db08995d 93 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 94 led1 = ppp.ledState;
nixnax 43:aa57db08995d 95 }
nixnax 43:aa57db08995d 96
nixnax 29:30de79d658f6 97 void crcReset()
nixnax 29:30de79d658f6 98 {
nixnax 29:30de79d658f6 99 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 100 }
nixnax 4:a469050d5b80 101
nixnax 29:30de79d658f6 102 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 103 {
nixnax 29:30de79d658f6 104 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 105 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 106 x>>=1;
nixnax 29:30de79d658f6 107 }
nixnax 29:30de79d658f6 108 }
nixnax 29:30de79d658f6 109
nixnax 29:30de79d658f6 110 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 111 {
nixnax 31:e000c1b9c565 112 crcReset();
nixnax 31:e000c1b9c565 113 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 114 return ppp.crc;
nixnax 29:30de79d658f6 115 }
nixnax 0:2cf4880c312a 116
nixnax 0:2cf4880c312a 117 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 118 {
nixnax 17:4918c893d802 119 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 120 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 121 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 122 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 123 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 124 }
nixnax 0:2cf4880c312a 125 }
nixnax 0:2cf4880c312a 126
nixnax 22:00df34cd4d7e 127 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 128 {
nixnax 22:00df34cd4d7e 129 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 130 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 131 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 132 return emptyStatus;
nixnax 0:2cf4880c312a 133 }
nixnax 0:2cf4880c312a 134
nixnax 0:2cf4880c312a 135 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 136 {
nixnax 22:00df34cd4d7e 137 if ( rxbufNotEmpty() ) {
nixnax 4:a469050d5b80 138 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 20:5db9b77b38a6 139 __disable_irq(); // critical section start
nixnax 29:30de79d658f6 140 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 20:5db9b77b38a6 141 __enable_irq(); // critical section end
nixnax 0:2cf4880c312a 142 return x;
nixnax 20:5db9b77b38a6 143 } else return -1;
nixnax 0:2cf4880c312a 144 }
nixnax 0:2cf4880c312a 145
nixnax 29:30de79d658f6 146 void processFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 147 {
nixnax 38:ab582987926e 148 led1Toggle(); // change led1 state on every frame we receive
nixnax 29:30de79d658f6 149 if(start==end) {
nixnax 29:30de79d658f6 150 pc.putc(0x7e);
nixnax 29:30de79d658f6 151 return;
nixnax 29:30de79d658f6 152 }
nixnax 9:0992486d4a30 153 crcReset();
nixnax 9:0992486d4a30 154 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 155 ppp.pkt.len=0;
nixnax 9:0992486d4a30 156 int unstuff=0;
nixnax 17:4918c893d802 157 int idx = start;
nixnax 17:4918c893d802 158 while(1) {
nixnax 9:0992486d4a30 159 if (unstuff==0) {
nixnax 29:30de79d658f6 160 if (rxbuf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 161 else {
nixnax 29:30de79d658f6 162 *dest = rxbuf[idx];
nixnax 29:30de79d658f6 163 ppp.pkt.len++;
nixnax 29:30de79d658f6 164 dest++;
nixnax 29:30de79d658f6 165 crcDo(rxbuf[idx]);
nixnax 29:30de79d658f6 166 }
nixnax 12:db0dc91f0231 167 } else { // unstuff
nixnax 29:30de79d658f6 168 *dest = rxbuf[idx]^0x20;
nixnax 29:30de79d658f6 169 ppp.pkt.len++;
nixnax 29:30de79d658f6 170 dest++;
nixnax 29:30de79d658f6 171 crcDo(rxbuf[idx]^0x20);
nixnax 9:0992486d4a30 172 unstuff=0;
nixnax 9:0992486d4a30 173 }
nixnax 17:4918c893d802 174 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 175 if (idx == end) break;
nixnax 9:0992486d4a30 176 }
nixnax 29:30de79d658f6 177 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 178 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 179 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 180 determinePacketType();
nixnax 29:30de79d658f6 181 } else if (v0) {
nixnax 42:4de44be70bfd 182 debug("PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len);
nixnax 9:0992486d4a30 183 }
nixnax 9:0992486d4a30 184 }
nixnax 9:0992486d4a30 185
nixnax 38:ab582987926e 186 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 187 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 188 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 189 void dumpFrame()
nixnax 29:30de79d658f6 190 {
nixnax 42:4de44be70bfd 191 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 192 debug(" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len);
nixnax 16:cb0b80c24ba2 193 }
nixnax 16:cb0b80c24ba2 194
nixnax 29:30de79d658f6 195 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 196 {
nixnax 29:30de79d658f6 197 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 198 pc.putc(0x7d);
nixnax 38:ab582987926e 199 pc.putc(ch^0x20); // three characters need special handling
nixnax 29:30de79d658f6 200 } else {
nixnax 29:30de79d658f6 201 pc.putc(ch);
nixnax 29:30de79d658f6 202 }
nixnax 11:f58998c24f0b 203 }
nixnax 9:0992486d4a30 204
nixnax 38:ab582987926e 205 void sendFrame() // send one PPP frame in HDLC format
nixnax 29:30de79d658f6 206 {
nixnax 17:4918c893d802 207 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 208 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 209 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 210 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 211 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 212 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 213 }
nixnax 9:0992486d4a30 214
nixnax 29:30de79d658f6 215 void ipRequestHandler()
nixnax 29:30de79d658f6 216 {
nixnax 15:b0154c910143 217 debug(("IPCP Conf "));
nixnax 9:0992486d4a30 218 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 15:b0154c910143 219 debug(("Rej\n")); // reject if any options are requested
nixnax 9:0992486d4a30 220 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 221 sendFrame();
nixnax 9:0992486d4a30 222 } else {
nixnax 15:b0154c910143 223 debug(("Ack\n"));
nixnax 9:0992486d4a30 224 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 225 sendFrame(); // acknowledge
nixnax 29:30de79d658f6 226 debug(("IPCP Ask\n"));
nixnax 9:0992486d4a30 227 // send our own request now
nixnax 12:db0dc91f0231 228 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 229 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 230 sendFrame(); // this is our request
nixnax 9:0992486d4a30 231 }
nixnax 9:0992486d4a30 232 }
nixnax 9:0992486d4a30 233
nixnax 29:30de79d658f6 234 void ipAckHandler()
nixnax 29:30de79d658f6 235 {
nixnax 29:30de79d658f6 236 debug(("IPCP Grant\n"));
nixnax 29:30de79d658f6 237 }
nixnax 9:0992486d4a30 238
nixnax 29:30de79d658f6 239 void ipNackHandler()
nixnax 29:30de79d658f6 240 {
nixnax 29:30de79d658f6 241 debug(("IPCP Nack\n"));
nixnax 29:30de79d658f6 242 }
nixnax 9:0992486d4a30 243
nixnax 29:30de79d658f6 244 void ipDefaultHandler()
nixnax 29:30de79d658f6 245 {
nixnax 29:30de79d658f6 246 debug(("IPCP Other\n"));
nixnax 29:30de79d658f6 247 }
nixnax 29:30de79d658f6 248
nixnax 29:30de79d658f6 249 void IPCPframe()
nixnax 29:30de79d658f6 250 {
nixnax 9:0992486d4a30 251 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 252 switch (code) {
nixnax 29:30de79d658f6 253 case 1:
nixnax 29:30de79d658f6 254 ipRequestHandler();
nixnax 29:30de79d658f6 255 break;
nixnax 29:30de79d658f6 256 case 2:
nixnax 29:30de79d658f6 257 ipAckHandler();
nixnax 29:30de79d658f6 258 break;
nixnax 29:30de79d658f6 259 case 3:
nixnax 29:30de79d658f6 260 ipNackHandler();
nixnax 29:30de79d658f6 261 break;
nixnax 29:30de79d658f6 262 default:
nixnax 29:30de79d658f6 263 ipDefaultHandler();
nixnax 9:0992486d4a30 264 }
nixnax 29:30de79d658f6 265 }
nixnax 9:0992486d4a30 266
nixnax 29:30de79d658f6 267 void UDPpacket()
nixnax 29:30de79d658f6 268 {
nixnax 12:db0dc91f0231 269 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 270 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 271 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 12:db0dc91f0231 272 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 273 char * udpDst = udpBlock+2; // destination port
nixnax 12:db0dc91f0231 274 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 275 char * udpInf = udpBlock+8; // actual start of info
nixnax 12:db0dc91f0231 276 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 277 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 278 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 279 char * dstIP = udpPkt+16; // udp dst addr
nixnax 29:30de79d658f6 280 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 281 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 42:4de44be70bfd 282 if(v1) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 42:4de44be70bfd 283 if(v1) debug("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort);
nixnax 42:4de44be70bfd 284 debug("Len %d ", udpLength);
nixnax 29:30de79d658f6 285 int printSize = udpLength;
nixnax 29:30de79d658f6 286 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 287 if (v0) {
nixnax 29:30de79d658f6 288 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 289 char ch = udpInf[i];
nixnax 29:30de79d658f6 290 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 291 debug("%c", ch);
nixnax 29:30de79d658f6 292 } else {
nixnax 29:30de79d658f6 293 debug(("_"));
nixnax 29:30de79d658f6 294 }
nixnax 29:30de79d658f6 295 }
nixnax 29:30de79d658f6 296 debug(("\n"));
nixnax 29:30de79d658f6 297 }
nixnax 12:db0dc91f0231 298 }
nixnax 11:f58998c24f0b 299
nixnax 29:30de79d658f6 300 int dataCheckSum(char * ptr, int len)
nixnax 29:30de79d658f6 301 {
nixnax 29:30de79d658f6 302 int sum=0;
nixnax 29:30de79d658f6 303 int placeHolder;
nixnax 29:30de79d658f6 304 if (len&1) {
nixnax 38:ab582987926e 305 placeHolder = ptr[len-1]; // when length is odd stuff in a zero byte
nixnax 29:30de79d658f6 306 ptr[len-1]=0;
nixnax 29:30de79d658f6 307 }
nixnax 29:30de79d658f6 308 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 309 int hi = *ptr;
nixnax 29:30de79d658f6 310 ptr++;
nixnax 29:30de79d658f6 311 int lo = *ptr;
nixnax 29:30de79d658f6 312 ptr++;
nixnax 11:f58998c24f0b 313 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 314 sum = sum + val;
nixnax 11:f58998c24f0b 315 }
nixnax 11:f58998c24f0b 316 sum = sum + (sum>>16);
nixnax 29:30de79d658f6 317 if (len&1) {
nixnax 29:30de79d658f6 318 ptr[len-1] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 319 }
nixnax 12:db0dc91f0231 320 return ~sum;
nixnax 29:30de79d658f6 321 }
nixnax 11:f58998c24f0b 322
nixnax 29:30de79d658f6 323 void headerCheckSum()
nixnax 29:30de79d658f6 324 {
nixnax 11:f58998c24f0b 325 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 326 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 327 int sum=0;
nixnax 11:f58998c24f0b 328
nixnax 29:30de79d658f6 329 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 330 int hi = *ptr;
nixnax 29:30de79d658f6 331 ptr++;
nixnax 29:30de79d658f6 332 int lo = *ptr;
nixnax 29:30de79d658f6 333 ptr++;
nixnax 11:f58998c24f0b 334 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 335 sum = sum + val;
nixnax 11:f58998c24f0b 336 }
nixnax 11:f58998c24f0b 337 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 338 sum = ~sum;
nixnax 11:f58998c24f0b 339 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 340 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 341 }
nixnax 9:0992486d4a30 342
nixnax 29:30de79d658f6 343 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 344 {
nixnax 12:db0dc91f0231 345 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 346 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 347 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 348 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 349 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 350 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 351 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 352 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 353 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 354 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 355 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 356 char * dstAdr = ipPkt+16;
nixnax 18:3e35de1bc877 357 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 358 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 42:4de44be70bfd 359 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 360 debug("Ident %04x Sequence %04d ",icmpIdent,icmpSequence);
nixnax 29:30de79d658f6 361 char src[4];
nixnax 29:30de79d658f6 362 char dst[4];
nixnax 12:db0dc91f0231 363 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 364 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 365 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 366 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 367 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 368 chkSum[0]=0;
nixnax 29:30de79d658f6 369 chkSum[1]=0;
nixnax 12:db0dc91f0231 370 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 371 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 372 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 373 icmpSum[0]=0;
nixnax 29:30de79d658f6 374 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 375 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 16:cb0b80c24ba2 376 int sum = dataCheckSum( icmpType, icmpLength); // this checksum on icmp data portion
nixnax 29:30de79d658f6 377 icmpSum[0]=sum>>8;
nixnax 29:30de79d658f6 378 icmpSum[1]=sum; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 379
nixnax 16:cb0b80c24ba2 380 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 381 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 382 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 383 if (v0) {
nixnax 29:30de79d658f6 384 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 385 char ch = icmpData[i];
nixnax 29:30de79d658f6 386 if (ch>31 && ch<127) {
nixnax 42:4de44be70bfd 387 debug("%c",ch);
nixnax 29:30de79d658f6 388 } else {
nixnax 29:30de79d658f6 389 debug(("_"));
nixnax 29:30de79d658f6 390 }
nixnax 29:30de79d658f6 391 }
nixnax 29:30de79d658f6 392 debug(("\n"));
nixnax 29:30de79d658f6 393 }
nixnax 15:b0154c910143 394 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 395
nixnax 12:db0dc91f0231 396 } else {
nixnax 29:30de79d658f6 397 if (v0) {
nixnax 42:4de44be70bfd 398 debug("ICMP type=%d \n", icmpType[0]);
nixnax 29:30de79d658f6 399 }
nixnax 11:f58998c24f0b 400 }
nixnax 11:f58998c24f0b 401 }
nixnax 11:f58998c24f0b 402
nixnax 29:30de79d658f6 403 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 404 {
nixnax 29:30de79d658f6 405 if (v0) {
nixnax 42:4de44be70bfd 406 debug("IGMP type=%d \n", ppp.pkt.buf[28]);
nixnax 29:30de79d658f6 407 }
nixnax 29:30de79d658f6 408 }
nixnax 11:f58998c24f0b 409
nixnax 29:30de79d658f6 410 void dumpHeaderIP ()
nixnax 29:30de79d658f6 411 {
nixnax 26:11f4eb2663a7 412 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 413 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 414 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 415 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 416 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 417 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 418 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 419 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 420 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 421 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 422 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 423 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 424 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 425
nixnax 29:30de79d658f6 426 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 427 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 428 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 429 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 430 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 431 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 432 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 433 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 434 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 435 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 29:30de79d658f6 436 char srcIP [16];
nixnax 29:30de79d658f6 437 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 438 char dstIP [16];
nixnax 29:30de79d658f6 439 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 42:4de44be70bfd 440 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 441 if (v0) debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 442 }
nixnax 26:11f4eb2663a7 443
nixnax 29:30de79d658f6 444 void dumpHeaderTCP()
nixnax 29:30de79d658f6 445 {
nixnax 29:30de79d658f6 446 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 447 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 29:30de79d658f6 448 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 449 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 29:30de79d658f6 450 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 31:e000c1b9c565 451 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 452 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 26:11f4eb2663a7 453 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 454
nixnax 29:30de79d658f6 455 char flagInfo[10];
nixnax 29:30de79d658f6 456 memset(flagInfo,'.',10); // text presentation of TCP flags
nixnax 29:30de79d658f6 457 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 458 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 459 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 460 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 461 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 462 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 463 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 464 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 465 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 29:30de79d658f6 466 flagInfo[9]=0; // null terminate string
nixnax 29:30de79d658f6 467 if (v0) {
nixnax 42:4de44be70bfd 468 debug("Flags %s Seq %u Ack %u", flagInfo, seq, ack);
nixnax 29:30de79d658f6 469 }
nixnax 29:30de79d658f6 470 }
nixnax 29:30de79d658f6 471
nixnax 29:30de79d658f6 472 void tcpHandler()
nixnax 29:30de79d658f6 473 {
nixnax 26:11f4eb2663a7 474 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 475 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 476 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 477 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 478 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 479 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 480 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 481 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 482 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 483 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 484
nixnax 29:30de79d658f6 485 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 486 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 487
nixnax 29:30de79d658f6 488 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 489 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 490 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 491 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 492 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 493 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 494 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 495 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 496
nixnax 26:11f4eb2663a7 497 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 498 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 29:30de79d658f6 499
nixnax 31:e000c1b9c565 500 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 501 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 29:30de79d658f6 502
nixnax 35:e7068df4d971 503 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 504
nixnax 35:e7068df4d971 505 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 35:e7068df4d971 506 int incomingLen = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 28:1aa629be05e7 507
nixnax 29:30de79d658f6 508 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 509 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 510 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 511 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 512 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 513
nixnax 38:ab582987926e 514 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 38:ab582987926e 515 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 38:ab582987926e 516 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 29:30de79d658f6 517
nixnax 35:e7068df4d971 518 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 519 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 520 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 521
nixnax 38:ab582987926e 522 if (ppp.seq != ack) {
nixnax 38:ab582987926e 523 ppp.seq = ack; // if their sequence number is different than our calculation we adopt their version
nixnax 38:ab582987926e 524 }
nixnax 35:e7068df4d971 525
nixnax 35:e7068df4d971 526 if ( ((flagsTCP & ~TCP_FLAG_ACK) == 0) && ((flagsTCP & TCP_FLAG_ACK) != 0) ) {
nixnax 38:ab582987926e 527 if (incomingLen == 0) { // ignore - just an empty ack packet
nixnax 38:ab582987926e 528 return;
nixnax 38:ab582987926e 529 }
nixnax 38:ab582987926e 530 } else if ( (flagsTCP & TCP_FLAG_SYN) != 0 ) { // got SYN flag
nixnax 36:2a9b457f8276 531 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // do a syn-ack
nixnax 38:ab582987926e 532 seq++; // for SYN flag we have to increase sequence by 1
nixnax 38:ab582987926e 533 } else if ( (flagsTCP & TCP_FLAG_FIN) != 0 ) { // got FIN flag
nixnax 38:ab582987926e 534 seq++; // for FIN flag we have to increase sequence by 1
nixnax 38:ab582987926e 535 } else if ( (flagsTCP & TCP_FLAG_PSH) != 0 ) { // got PSH flag (push)
nixnax 38:ab582987926e 536 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 38:ab582987926e 537 fastResponse = 1; // we can respond fast to a push
nixnax 38:ab582987926e 538 // It's a push, so let's check the incoming data for an HTTP GET request
nixnax 31:e000c1b9c565 539 if ( strncmp(dataStart, "GET / HTTP/1.1", 14) == 0) {
nixnax 41:e58a5a09f411 540 dataLen = 17*32; // this block has to hold the web page below, but keep it under 1k
nixnax 38:ab582987926e 541 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 38:ab582987926e 542 int n=0; // number of bytes we have printed so far
nixnax 31:e000c1b9c565 543 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 41:e58a5a09f411 544 n=n+sprintf(n+dataStart,"Content-Length: 441\r\n"); // http header
nixnax 32:512228c29209 545 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header
nixnax 31:e000c1b9c565 546 int nHeader=n; // byte total of all headers
nixnax 41:e58a5a09f411 547 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head><title>mbed-PPP-Blinky</title>\n<script>window.onload=function()"); // html
nixnax 31:e000c1b9c565 548 n=n+sprintf(n+dataStart,"{setInterval(function(){function x(){return document.getElementById('w');};"); // html
nixnax 41:e58a5a09f411 549 n=n+sprintf(n+dataStart,"x().textContent = parseInt(x().textContent)+1;},100);};</script>\n</head><body style=\"font-size:30px; color:#807070\">"); // html
nixnax 41:e58a5a09f411 550 n=n+sprintf(n+dataStart,"<h1>mbed PPP-Blinky Up and Running</h1><h1 id=\"w\" style=\"text-align:"); // html
nixnax 41:e58a5a09f411 551 n=n+sprintf(n+dataStart," center;\">0</h1><h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1></body></html>"); // html
nixnax 31:e000c1b9c565 552 int contentLength = dataLen-nHeader; // this is how to calculate Content-Length, but using curl -v is easier
nixnax 31:e000c1b9c565 553 contentLength = contentLength+0; // get around unreferenced variable warning
nixnax 31:e000c1b9c565 554 if (v0) {
nixnax 42:4de44be70bfd 555 debug("HTTP GET dataLen %d*32=%d Header %d Content-Length %d Total %d Margin %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n);
nixnax 31:e000c1b9c565 556 }
nixnax 38:ab582987926e 557 } else if ( strncmp(dataStart, "GET /", 4) == 0) { // all other HTTP GET requests get 404 Not Found response
nixnax 38:ab582987926e 558 dataLen = 5*32; // block size for File not found webpage
nixnax 38:ab582987926e 559 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 38:ab582987926e 560 int n=0; // number of bytes we have printed so far
nixnax 41:e58a5a09f411 561 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 32:512228c29209 562 n=n+sprintf(n+dataStart,"Content-Length: 58\r\n"); // http header
nixnax 32:512228c29209 563 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header
nixnax 32:512228c29209 564 int nHeader=n; // byte total of all headers
nixnax 32:512228c29209 565 n=n+sprintf(n+dataStart,"<html><head>"); // html
nixnax 32:512228c29209 566 n=n+sprintf(n+dataStart,"<body><h1>File Not Found</h1></body>\r\n</html>"); // html
nixnax 32:512228c29209 567 int contentLength = dataLen-nHeader; // this is how to calculate Content-Length, but using curl -v is easier
nixnax 32:512228c29209 568 contentLength = contentLength+0; // get around unreferenced variable warning
nixnax 31:e000c1b9c565 569 if (v0) {
nixnax 42:4de44be70bfd 570 debug("HTTP GET dataLen %d*32=%d Header %d Content-Length %d Total %d Margin %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n);
nixnax 31:e000c1b9c565 571 }
nixnax 35:e7068df4d971 572 } else {
nixnax 38:ab582987926e 573 dataLen=0; // we did not find a valid HTTP request, so just ACK with zero data
nixnax 29:30de79d658f6 574 }
nixnax 36:2a9b457f8276 575 } else {
nixnax 38:ab582987926e 576 dataLen=0; // it's not any TCP Flag Combo that needs special handling
nixnax 28:1aa629be05e7 577 }
nixnax 29:30de79d658f6 578
nixnax 38:ab582987926e 579 // All the TCP flag handling is now done
nixnax 29:30de79d658f6 580
nixnax 38:ab582987926e 581 // 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 582
nixnax 38:ab582987926e 583 char src[4]; // temp hold
nixnax 38:ab582987926e 584 char dst[4]; // temp hold
nixnax 29:30de79d658f6 585 memcpy(src, srcAdr,4);
nixnax 29:30de79d658f6 586 memcpy(dst, dstAdr,4);
nixnax 29:30de79d658f6 587 memcpy(srcAdr, dst,4);
nixnax 29:30de79d658f6 588 memcpy(dstAdr, src,4); // swap ip address source/dest
nixnax 38:ab582987926e 589
nixnax 38:ab582987926e 590 char psrc[2]; // temp hold
nixnax 38:ab582987926e 591 char pdst[2]; // temp hold
nixnax 29:30de79d658f6 592 memcpy(psrc, srctcp,2);
nixnax 29:30de79d658f6 593 memcpy(pdst, dsttcp,2);
nixnax 29:30de79d658f6 594 memcpy(srctcp, pdst,2);
nixnax 29:30de79d658f6 595 memcpy(dsttcp, psrc,2); // swap ip port source/dest
nixnax 29:30de79d658f6 596
nixnax 38:ab582987926e 597 ack = seq + incomingLen; // acknowledge the number of bytes that they sent by adding it to "our" sequence number
nixnax 38:ab582987926e 598 seq = ppp.seq; // set up the sequence number we have to respond with
nixnax 38:ab582987926e 599
nixnax 38:ab582987926e 600 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 601 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 602 acktcp[2]=ack>>8;
nixnax 38:ab582987926e 603 acktcp[3]=ack>>0; // save ack
nixnax 38:ab582987926e 604
nixnax 38:ab582987926e 605 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 606 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 607 seqtcp[2]=seq>>8;
nixnax 38:ab582987926e 608 seqtcp[3]=seq>>0; // save seq
nixnax 38:ab582987926e 609
nixnax 38:ab582987926e 610 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 611
nixnax 38:ab582987926e 612 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 613 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 614 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 615 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 616 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 617
nixnax 38:ab582987926e 618 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 619
nixnax 29:30de79d658f6 620 headercheck[0]=0;
nixnax 29:30de79d658f6 621 headercheck[1]=0;
nixnax 29:30de79d658f6 622 headerCheckSum(); // redo the ip header checksum
nixnax 38:ab582987926e 623
nixnax 38:ab582987926e 624 char pseudoHeader[12]; // we are building a fake TCP header
nixnax 29:30de79d658f6 625 int sum;
nixnax 26:11f4eb2663a7 626 memcpy( pseudoHeader+0, srcAdr, 8); // source and destination addresses.
nixnax 29:30de79d658f6 627 pseudoHeader[8]=0;
nixnax 29:30de79d658f6 628 pseudoHeader[9]=protocol[0];
nixnax 29:30de79d658f6 629 pseudoHeader[10]=tcpSize>>8;
nixnax 29:30de79d658f6 630 pseudoHeader[11]=tcpSize;
nixnax 38:ab582987926e 631 char temp[12]; // temporary storage for the 12 bytes that are in the way
nixnax 38:ab582987926e 632 memcpy(temp, s-12, 12); // save the 12 bytes that are in the way
nixnax 38:ab582987926e 633 memcpy( s-12, pseudoHeader, 12); // copy in the fake header
nixnax 29:30de79d658f6 634 checksumtcp[0]=0;
nixnax 29:30de79d658f6 635 checksumtcp[1]=0;
nixnax 38:ab582987926e 636 sum=dataCheckSum(s-12,tcpSize+12); // calculate the TCP checksum
nixnax 29:30de79d658f6 637 checksumtcp[0]=sum>>8;
nixnax 29:30de79d658f6 638 checksumtcp[1]=sum;
nixnax 38:ab582987926e 639 memcpy( s-12, temp, 12); // restore the 12 bytes that the fake header overwrote
nixnax 36:2a9b457f8276 640 if (fastResponse==1) {
nixnax 36:2a9b457f8276 641 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 642 } else {
nixnax 38:ab582987926e 643 wait(0.2); // normally, you wait 200 ms before sending a TCP packet
nixnax 36:2a9b457f8276 644 }
nixnax 38:ab582987926e 645 sendFrame(); // All done! Send the TCP packet
nixnax 38:ab582987926e 646 ppp.seq = ppp.seq + dataLen; // increase OUR sequence by the outgoing data length - for the next round
nixnax 29:30de79d658f6 647 }
nixnax 26:11f4eb2663a7 648
nixnax 29:30de79d658f6 649 void dumpDataTCP()
nixnax 29:30de79d658f6 650 {
nixnax 26:11f4eb2663a7 651 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 652 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 653 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 654 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 655 if (v1) {
nixnax 42:4de44be70bfd 656 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 657 }
nixnax 29:30de79d658f6 658 if (dataLen > 0) {
nixnax 42:4de44be70bfd 659 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 660 }
nixnax 29:30de79d658f6 661 }
nixnax 26:11f4eb2663a7 662
nixnax 29:30de79d658f6 663 void TCPpacket()
nixnax 29:30de79d658f6 664 {
nixnax 26:11f4eb2663a7 665 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 666 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 667 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 668 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 669 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 670 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 671 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 672 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 673 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 674 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 675 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 676 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 677 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 678
nixnax 29:30de79d658f6 679 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 680 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 681 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 682 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 683 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 684 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 685 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 686 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 687 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 688 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 29:30de79d658f6 689 char srcIP [16];
nixnax 29:30de79d658f6 690 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 691 char dstIP [16];
nixnax 29:30de79d658f6 692 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 693 if (v0) {
nixnax 42:4de44be70bfd 694 debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 29:30de79d658f6 695 }
nixnax 29:30de79d658f6 696 if (v0) {
nixnax 42:4de44be70bfd 697 debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 698 }
nixnax 28:1aa629be05e7 699 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 700 dumpDataTCP();
nixnax 26:11f4eb2663a7 701 tcpHandler();
nixnax 11:f58998c24f0b 702 }
nixnax 11:f58998c24f0b 703
nixnax 29:30de79d658f6 704 void otherProtocol()
nixnax 29:30de79d658f6 705 {
nixnax 29:30de79d658f6 706 debug(("Other IP protocol"));
nixnax 29:30de79d658f6 707 }
nixnax 26:11f4eb2663a7 708
nixnax 29:30de79d658f6 709 void IPframe()
nixnax 29:30de79d658f6 710 {
nixnax 10:74f8233f72c0 711 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 712 switch (protocol) {
nixnax 29:30de79d658f6 713 case 1:
nixnax 29:30de79d658f6 714 ICMPpacket();
nixnax 29:30de79d658f6 715 break;
nixnax 29:30de79d658f6 716 case 2:
nixnax 29:30de79d658f6 717 IGMPpacket();
nixnax 29:30de79d658f6 718 break;
nixnax 29:30de79d658f6 719 case 17:
nixnax 29:30de79d658f6 720 UDPpacket();
nixnax 29:30de79d658f6 721 break;
nixnax 29:30de79d658f6 722 case 6:
nixnax 29:30de79d658f6 723 TCPpacket();
nixnax 29:30de79d658f6 724 break;
nixnax 29:30de79d658f6 725 default:
nixnax 29:30de79d658f6 726 otherProtocol();
nixnax 29:30de79d658f6 727 }
nixnax 29:30de79d658f6 728 }
nixnax 9:0992486d4a30 729
nixnax 29:30de79d658f6 730 void LCPconfReq()
nixnax 29:30de79d658f6 731 {
nixnax 15:b0154c910143 732 debug(("LCP Config "));
nixnax 9:0992486d4a30 733 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 734 ppp.pkt.buf[4]=4; // allow only no options
nixnax 15:b0154c910143 735 debug(("Reject\n"));
nixnax 29:30de79d658f6 736 sendFrame();
nixnax 9:0992486d4a30 737 } else {
nixnax 9:0992486d4a30 738 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 15:b0154c910143 739 debug(("Ack\n"));
nixnax 9:0992486d4a30 740 sendFrame();
nixnax 15:b0154c910143 741 debug(("LCP Ask\n"));
nixnax 11:f58998c24f0b 742 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 743 sendFrame();
nixnax 9:0992486d4a30 744 }
nixnax 9:0992486d4a30 745 }
nixnax 9:0992486d4a30 746
nixnax 29:30de79d658f6 747 void LCPconfAck()
nixnax 29:30de79d658f6 748 {
nixnax 15:b0154c910143 749 debug(("LCP Ack\n"));
nixnax 29:30de79d658f6 750 }
nixnax 9:0992486d4a30 751
nixnax 29:30de79d658f6 752 void LCPend()
nixnax 29:30de79d658f6 753 {
nixnax 29:30de79d658f6 754 debug(("LCP End\n"));
nixnax 29:30de79d658f6 755 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 756 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 757 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 758 }
nixnax 9:0992486d4a30 759
nixnax 29:30de79d658f6 760 void LCPother()
nixnax 29:30de79d658f6 761 {
nixnax 29:30de79d658f6 762 debug(("LCP Other\n"));
nixnax 29:30de79d658f6 763 dumpFrame();
nixnax 29:30de79d658f6 764 }
nixnax 29:30de79d658f6 765
nixnax 29:30de79d658f6 766 void LCPframe()
nixnax 29:30de79d658f6 767 {
nixnax 29:30de79d658f6 768 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 769 switch (code) {
nixnax 29:30de79d658f6 770 case 1:
nixnax 29:30de79d658f6 771 LCPconfReq();
nixnax 29:30de79d658f6 772 break; // config request
nixnax 29:30de79d658f6 773 case 2:
nixnax 29:30de79d658f6 774 LCPconfAck();
nixnax 29:30de79d658f6 775 break; // config ack
nixnax 29:30de79d658f6 776 case 5:
nixnax 29:30de79d658f6 777 LCPend();
nixnax 29:30de79d658f6 778 break; // end connection
nixnax 29:30de79d658f6 779 default:
nixnax 29:30de79d658f6 780 LCPother();
nixnax 29:30de79d658f6 781 }
nixnax 9:0992486d4a30 782 }
nixnax 9:0992486d4a30 783
nixnax 29:30de79d658f6 784 void discardedFrame()
nixnax 29:30de79d658f6 785 {
nixnax 29:30de79d658f6 786 if (v0) {
nixnax 42:4de44be70bfd 787 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 788 }
nixnax 9:0992486d4a30 789 }
nixnax 9:0992486d4a30 790
nixnax 29:30de79d658f6 791 void determinePacketType()
nixnax 29:30de79d658f6 792 {
nixnax 29:30de79d658f6 793 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 29:30de79d658f6 794 debug(("byte0 != ff\n"));
nixnax 29:30de79d658f6 795 return;
nixnax 29:30de79d658f6 796 }
nixnax 29:30de79d658f6 797 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 29:30de79d658f6 798 debug(("byte1 != 3\n"));
nixnax 29:30de79d658f6 799 return;
nixnax 29:30de79d658f6 800 }
nixnax 29:30de79d658f6 801 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 29:30de79d658f6 802 debug(("byte2 != 21\n"));
nixnax 29:30de79d658f6 803 return;
nixnax 29:30de79d658f6 804 }
nixnax 9:0992486d4a30 805 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 806 switch (packetType) {
nixnax 29:30de79d658f6 807 case 0xc0:
nixnax 29:30de79d658f6 808 LCPframe();
nixnax 29:30de79d658f6 809 break; // link control
nixnax 29:30de79d658f6 810 case 0x80:
nixnax 29:30de79d658f6 811 IPCPframe();
nixnax 29:30de79d658f6 812 break; // IP control
nixnax 29:30de79d658f6 813 case 0x00:
nixnax 29:30de79d658f6 814 IPframe();
nixnax 29:30de79d658f6 815 break; // IP itself
nixnax 29:30de79d658f6 816 default:
nixnax 29:30de79d658f6 817 discardedFrame();
nixnax 9:0992486d4a30 818 }
nixnax 29:30de79d658f6 819 }
nixnax 9:0992486d4a30 820
nixnax 29:30de79d658f6 821 void scanForConnectString()
nixnax 29:30de79d658f6 822 {
nixnax 9:0992486d4a30 823 if ( ppp.online==0 ) {
nixnax 15:b0154c910143 824 char * clientFound = strstr( (char *)rxbuf, "CLIENTCLIENT" ); // look for PC string
nixnax 29:30de79d658f6 825 if( clientFound ) {
nixnax 9:0992486d4a30 826 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't get fixated
nixnax 9:0992486d4a30 827 pc.printf("CLIENTSERVER"); // respond to PC
nixnax 9:0992486d4a30 828 ppp.online=1; // we can stop looking for the string
nixnax 15:b0154c910143 829 debug(("Connect string found\n"));
nixnax 9:0992486d4a30 830 }
nixnax 9:0992486d4a30 831 }
nixnax 9:0992486d4a30 832 }
nixnax 9:0992486d4a30 833
nixnax 0:2cf4880c312a 834 int main()
nixnax 0:2cf4880c312a 835 {
nixnax 14:c65831c25aaa 836 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 837 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 15:b0154c910143 838 xx.baud(115200); // second serial port for debug(((((((( messages
nixnax 9:0992486d4a30 839 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 840 #endif
nixnax 9:0992486d4a30 841 pppInitStruct(); // initialize all the PPP properties
nixnax 4:a469050d5b80 842
nixnax 9:0992486d4a30 843 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 4:a469050d5b80 844
nixnax 29:30de79d658f6 845 int frameStartIndex, frameEndIndex;
nixnax 29:30de79d658f6 846 int frameBusy=0;
nixnax 4:a469050d5b80 847
nixnax 0:2cf4880c312a 848 while(1) {
nixnax 9:0992486d4a30 849 if ( ppp.online==0 ) scanForConnectString(); // try to connect
nixnax 22:00df34cd4d7e 850 while ( rxbufNotEmpty() ) {
nixnax 1:9e03798d4367 851 int rx = pc_getBuf();
nixnax 29:30de79d658f6 852 if (frameBusy) {
nixnax 4:a469050d5b80 853 if (rx==FRAME_7E) {
nixnax 4:a469050d5b80 854 frameBusy=0; // done gathering frame
nixnax 4:a469050d5b80 855 frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 4:a469050d5b80 856 processFrame(frameStartIndex, frameEndIndex);
nixnax 4:a469050d5b80 857 }
nixnax 29:30de79d658f6 858 } else {
nixnax 4:a469050d5b80 859 if (rx==FRAME_7E) {
nixnax 4:a469050d5b80 860 frameBusy=1; // start gathering frame
nixnax 9:0992486d4a30 861 frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 4:a469050d5b80 862 }
nixnax 0:2cf4880c312a 863 }
nixnax 4:a469050d5b80 864 }
nixnax 7:ab147f5e97ac 865 }
nixnax 7:ab147f5e97ac 866 }