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@36:2a9b457f8276, 2017-01-05 (annotated)

Committer:
nixnax
Date:
Thu Jan 05 10:32:12 2017 +0000
Revision:
36:2a9b457f8276
Parent:
35:e7068df4d971
Child:
37:2e6689f8b181
Remove teardown

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 0:2cf4880c312a 5 // Proof-of-concept for TCP/IP using Windows 7/8/10 Dial Up Networking over MBED USB Virtual COM Port
nixnax 0:2cf4880c312a 6
nixnax 4:a469050d5b80 7 // Toggles LED1 every time the PC sends an IP packet over the PPP link
nixnax 4:a469050d5b80 8
nixnax 29:30de79d658f6 9 // Note - turn off all Dial Up authentication, passwords, compression options - Simplest link possible.
nixnax 29:30de79d658f6 10 // Be sure to read the section on mbed on "Windows 7/8/10 PPP bug" if you keep on getting Dial Up Error 777.
nixnax 0:2cf4880c312a 11
nixnax 9:0992486d4a30 12 // Handy links
nixnax 29:30de79d658f6 13 // https://developer.mbed.org/users/nixnax/code/PPP-Blinky/ - Handy Notes, Instructions and introduction
nixnax 6:fba4c2e817b8 14 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 15 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 16 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 6:fba4c2e817b8 17
nixnax 29:30de79d658f6 18 // Handy tools
nixnax 29:30de79d658f6 19 // https://ttssh2.osdn.jp/index.html.en - A good terminal program to monitor the debug output from the second serial port with!
nixnax 29:30de79d658f6 20 // Wireshark - can't monitor Dial-Up network packets on windows, but very hand - can import our dumpFrame routine's hex output
nixnax 29:30de79d658f6 21 // Microsoft network monitor - real-time monitoring of all our packets
nixnax 29:30de79d658f6 22 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 29:30de79d658f6 23 // 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 29:30de79d658f6 24 // The curl program in Windows Powershell - use like this to test the webserver: while (1) { curl 172.10.10.1 }
nixnax 29:30de79d658f6 25 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 29:30de79d658f6 26 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from our board
nixnax 0:2cf4880c312a 27
nixnax 29:30de79d658f6 28 Serial pc(USBTX, USBRX); // The USB com port - Set this up as a Dial-Up Modem on your pc
nixnax 29:30de79d658f6 29 Serial xx(PC_10, PC_11); // See debug messages here. Not necessary to work, but VERY interesting output!
nixnax 29:30de79d658f6 30
nixnax 29:30de79d658f6 31 int v0=1;
nixnax 29:30de79d658f6 32 int v1=1; // verbosity flags used in debug printouts - change to 1/0 to see more/less debug info
nixnax 29:30de79d658f6 33
nixnax 29:30de79d658f6 34 // the commented #define below gets rid of ALL the debug printfs
nixnax 20:5db9b77b38a6 35 #define debug(x) xx.printf x
nixnax 19:e53cdee9a33c 36 //#define debug(x) {}
nixnax 9:0992486d4a30 37
nixnax 29:30de79d658f6 38 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 39
nixnax 29:30de79d658f6 40 // the standard hdlc frame start/end character
nixnax 4:a469050d5b80 41 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 42
nixnax 29:30de79d658f6 43 // the serial port receive buffer and packet buffer
nixnax 29:30de79d658f6 44 #define BUFLEN (1<<12)
nixnax 20:5db9b77b38a6 45 char rxbuf[BUFLEN];
nixnax 29:30de79d658f6 46 char frbuf[3000]; // send/receive buffer for ppp frames
nixnax 0:2cf4880c312a 47
nixnax 29:30de79d658f6 48 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 49 struct pppType {
nixnax 29:30de79d658f6 50 int online;
nixnax 26:11f4eb2663a7 51 int ident;
nixnax 28:1aa629be05e7 52 int sync;
nixnax 31:e000c1b9c565 53 unsigned int seq;
nixnax 29:30de79d658f6 54 int crc;
nixnax 29:30de79d658f6 55 int ledState;
nixnax 36:2a9b457f8276 56 int oldFlags;
nixnax 4:a469050d5b80 57 struct {
nixnax 20:5db9b77b38a6 58 char * buf;
nixnax 29:30de79d658f6 59 volatile int head;
nixnax 29:30de79d658f6 60 volatile int tail;
nixnax 9:0992486d4a30 61 int total;
nixnax 4:a469050d5b80 62 } rx; // serial port buffer
nixnax 4:a469050d5b80 63 struct {
nixnax 6:fba4c2e817b8 64 int id;
nixnax 4:a469050d5b80 65 int len;
nixnax 4:a469050d5b80 66 int crc;
nixnax 4:a469050d5b80 67 char * buf;
nixnax 4:a469050d5b80 68 } pkt; // ppp buffer
nixnax 29:30de79d658f6 69 };
nixnax 31:e000c1b9c565 70
nixnax 29:30de79d658f6 71 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 72
nixnax 29:30de79d658f6 73 // intitialize our globals
nixnax 29:30de79d658f6 74 void pppInitStruct()
nixnax 29:30de79d658f6 75 {
nixnax 29:30de79d658f6 76 ppp.online=0;
nixnax 29:30de79d658f6 77 ppp.rx.buf=rxbuf;
nixnax 29:30de79d658f6 78 ppp.rx.tail=0;
nixnax 29:30de79d658f6 79 ppp.rx.head=0;
nixnax 29:30de79d658f6 80 ppp.rx.total=0;
nixnax 29:30de79d658f6 81 ppp.pkt.buf=frbuf;
nixnax 29:30de79d658f6 82 ppp.pkt.len=0;
nixnax 29:30de79d658f6 83 ppp.ident=0;
nixnax 29:30de79d658f6 84 ppp.sync=0;
nixnax 35:e7068df4d971 85 ppp.seq=1000;
nixnax 29:30de79d658f6 86 ppp.ledState=0;
nixnax 36:2a9b457f8276 87 ppp.oldFlags=0;
nixnax 29:30de79d658f6 88 }
nixnax 26:11f4eb2663a7 89
nixnax 29:30de79d658f6 90 void crcReset()
nixnax 29:30de79d658f6 91 {
nixnax 29:30de79d658f6 92 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 93 }
nixnax 4:a469050d5b80 94
nixnax 29:30de79d658f6 95 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 96 {
nixnax 29:30de79d658f6 97 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 98 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 99 x>>=1;
nixnax 29:30de79d658f6 100 }
nixnax 29:30de79d658f6 101 }
nixnax 29:30de79d658f6 102
nixnax 29:30de79d658f6 103 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 104 {
nixnax 31:e000c1b9c565 105 crcReset();
nixnax 31:e000c1b9c565 106 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 107 return ppp.crc;
nixnax 29:30de79d658f6 108 }
nixnax 0:2cf4880c312a 109
nixnax 0:2cf4880c312a 110 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 111 {
nixnax 17:4918c893d802 112 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 113 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 114 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 115 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 116 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 117 }
nixnax 0:2cf4880c312a 118 }
nixnax 0:2cf4880c312a 119
nixnax 29:30de79d658f6 120 void led1Toggle()
nixnax 29:30de79d658f6 121 {
nixnax 29:30de79d658f6 122 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 29:30de79d658f6 123 led1 = ppp.ledState;
nixnax 14:c65831c25aaa 124 }
nixnax 14:c65831c25aaa 125
nixnax 22:00df34cd4d7e 126 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 127 {
nixnax 22:00df34cd4d7e 128 __disable_irq(); // critical section start
nixnax 29:30de79d658f6 129 int notEmpty = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 130 __enable_irq(); // critical section end
nixnax 22:00df34cd4d7e 131 return notEmpty;
nixnax 0:2cf4880c312a 132 }
nixnax 0:2cf4880c312a 133
nixnax 0:2cf4880c312a 134 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 135 {
nixnax 22:00df34cd4d7e 136 if ( rxbufNotEmpty() ) {
nixnax 4:a469050d5b80 137 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 20:5db9b77b38a6 138 __disable_irq(); // critical section start
nixnax 29:30de79d658f6 139 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 20:5db9b77b38a6 140 __enable_irq(); // critical section end
nixnax 0:2cf4880c312a 141 return x;
nixnax 20:5db9b77b38a6 142 } else return -1;
nixnax 0:2cf4880c312a 143 }
nixnax 0:2cf4880c312a 144
nixnax 4:a469050d5b80 145 void scanForConnectString(); // scan for connect attempts from pc
nixnax 1:9e03798d4367 146
nixnax 29:30de79d658f6 147 void processFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 148 {
nixnax 14:c65831c25aaa 149 led1Toggle(); // change led1 state when frames are received
nixnax 29:30de79d658f6 150 if(start==end) {
nixnax 29:30de79d658f6 151 pc.putc(0x7e);
nixnax 29:30de79d658f6 152 return;
nixnax 29:30de79d658f6 153 }
nixnax 9:0992486d4a30 154 crcReset();
nixnax 9:0992486d4a30 155 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 156 ppp.pkt.len=0;
nixnax 9:0992486d4a30 157 int unstuff=0;
nixnax 17:4918c893d802 158 int idx = start;
nixnax 17:4918c893d802 159 while(1) {
nixnax 9:0992486d4a30 160 if (unstuff==0) {
nixnax 29:30de79d658f6 161 if (rxbuf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 162 else {
nixnax 29:30de79d658f6 163 *dest = rxbuf[idx];
nixnax 29:30de79d658f6 164 ppp.pkt.len++;
nixnax 29:30de79d658f6 165 dest++;
nixnax 29:30de79d658f6 166 crcDo(rxbuf[idx]);
nixnax 29:30de79d658f6 167 }
nixnax 12:db0dc91f0231 168 } else { // unstuff
nixnax 29:30de79d658f6 169 *dest = rxbuf[idx]^0x20;
nixnax 29:30de79d658f6 170 ppp.pkt.len++;
nixnax 29:30de79d658f6 171 dest++;
nixnax 29:30de79d658f6 172 crcDo(rxbuf[idx]^0x20);
nixnax 9:0992486d4a30 173 unstuff=0;
nixnax 9:0992486d4a30 174 }
nixnax 17:4918c893d802 175 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 176 if (idx == end) break;
nixnax 9:0992486d4a30 177 }
nixnax 29:30de79d658f6 178 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 179 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 180 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 181 determinePacketType();
nixnax 29:30de79d658f6 182 } else if (v0) {
nixnax 29:30de79d658f6 183 debug(("PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len));
nixnax 9:0992486d4a30 184 }
nixnax 9:0992486d4a30 185 }
nixnax 9:0992486d4a30 186
nixnax 29:30de79d658f6 187 // Note - the hex output of dumpframe can be imported into WireShark
nixnax 29:30de79d658f6 188 // Copy the frame's hex output from your terminal program and save as a text file
nixnax 29:30de79d658f6 189 // In WireShark, use "Import Hex File". Options are No Offset, protocol=PPP.
nixnax 29:30de79d658f6 190 void dumpFrame()
nixnax 29:30de79d658f6 191 {
nixnax 29:30de79d658f6 192 for(int i=0; i<ppp.pkt.len; i++) debug(("%02x ", ppp.pkt.buf[i]));
nixnax 16:cb0b80c24ba2 193 debug((" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len));
nixnax 16:cb0b80c24ba2 194 }
nixnax 16:cb0b80c24ba2 195
nixnax 29:30de79d658f6 196 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 197 {
nixnax 29:30de79d658f6 198 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 199 pc.putc(0x7d);
nixnax 29:30de79d658f6 200 pc.putc(ch^0x20);
nixnax 29:30de79d658f6 201 } else {
nixnax 29:30de79d658f6 202 pc.putc(ch);
nixnax 29:30de79d658f6 203 }
nixnax 11:f58998c24f0b 204 }
nixnax 9:0992486d4a30 205
nixnax 29:30de79d658f6 206 void sendFrame()
nixnax 29:30de79d658f6 207 {
nixnax 17:4918c893d802 208 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 209 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 210 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 211 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 212 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 213 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 214 }
nixnax 9:0992486d4a30 215
nixnax 29:30de79d658f6 216 void ipRequestHandler()
nixnax 29:30de79d658f6 217 {
nixnax 15:b0154c910143 218 debug(("IPCP Conf "));
nixnax 9:0992486d4a30 219 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 15:b0154c910143 220 debug(("Rej\n")); // reject if any options are requested
nixnax 9:0992486d4a30 221 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 222 sendFrame();
nixnax 9:0992486d4a30 223 } else {
nixnax 15:b0154c910143 224 debug(("Ack\n"));
nixnax 9:0992486d4a30 225 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 226 sendFrame(); // acknowledge
nixnax 29:30de79d658f6 227 debug(("IPCP Ask\n"));
nixnax 9:0992486d4a30 228 // send our own request now
nixnax 12:db0dc91f0231 229 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 230 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 231 sendFrame(); // this is our request
nixnax 9:0992486d4a30 232 }
nixnax 9:0992486d4a30 233 }
nixnax 9:0992486d4a30 234
nixnax 29:30de79d658f6 235 void ipAckHandler()
nixnax 29:30de79d658f6 236 {
nixnax 29:30de79d658f6 237 debug(("IPCP Grant\n"));
nixnax 29:30de79d658f6 238 }
nixnax 9:0992486d4a30 239
nixnax 29:30de79d658f6 240 void ipNackHandler()
nixnax 29:30de79d658f6 241 {
nixnax 29:30de79d658f6 242 debug(("IPCP Nack\n"));
nixnax 29:30de79d658f6 243 }
nixnax 9:0992486d4a30 244
nixnax 29:30de79d658f6 245 void ipDefaultHandler()
nixnax 29:30de79d658f6 246 {
nixnax 29:30de79d658f6 247 debug(("IPCP Other\n"));
nixnax 29:30de79d658f6 248 }
nixnax 29:30de79d658f6 249
nixnax 29:30de79d658f6 250 void IPCPframe()
nixnax 29:30de79d658f6 251 {
nixnax 9:0992486d4a30 252 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 253 switch (code) {
nixnax 29:30de79d658f6 254 case 1:
nixnax 29:30de79d658f6 255 ipRequestHandler();
nixnax 29:30de79d658f6 256 break;
nixnax 29:30de79d658f6 257 case 2:
nixnax 29:30de79d658f6 258 ipAckHandler();
nixnax 29:30de79d658f6 259 break;
nixnax 29:30de79d658f6 260 case 3:
nixnax 29:30de79d658f6 261 ipNackHandler();
nixnax 29:30de79d658f6 262 break;
nixnax 29:30de79d658f6 263 default:
nixnax 29:30de79d658f6 264 ipDefaultHandler();
nixnax 9:0992486d4a30 265 }
nixnax 29:30de79d658f6 266 }
nixnax 9:0992486d4a30 267
nixnax 29:30de79d658f6 268 void UDPpacket()
nixnax 29:30de79d658f6 269 {
nixnax 12:db0dc91f0231 270 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 271 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 272 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 12:db0dc91f0231 273 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 274 char * udpDst = udpBlock+2; // destination port
nixnax 12:db0dc91f0231 275 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 276 char * udpInf = udpBlock+8; // actual start of info
nixnax 12:db0dc91f0231 277 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 278 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 279 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 280 char * dstIP = udpPkt+16; // udp dst addr
nixnax 29:30de79d658f6 281 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 282 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 29:30de79d658f6 283 if(v1) debug(("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort));
nixnax 29:30de79d658f6 284 if(v1) debug(("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort));
nixnax 15:b0154c910143 285 debug(("Len %d ", udpLength));
nixnax 29:30de79d658f6 286 int printSize = udpLength;
nixnax 29:30de79d658f6 287 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 288 if (v0) {
nixnax 29:30de79d658f6 289 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 290 char ch = udpInf[i];
nixnax 29:30de79d658f6 291 if (ch>31 && ch<127) {
nixnax 29:30de79d658f6 292 debug(("%c", ch));
nixnax 29:30de79d658f6 293 } else {
nixnax 29:30de79d658f6 294 debug(("_"));
nixnax 29:30de79d658f6 295 }
nixnax 29:30de79d658f6 296 }
nixnax 29:30de79d658f6 297 debug(("\n"));
nixnax 29:30de79d658f6 298 }
nixnax 12:db0dc91f0231 299 }
nixnax 11:f58998c24f0b 300
nixnax 29:30de79d658f6 301 int dataCheckSum(char * ptr, int len)
nixnax 29:30de79d658f6 302 {
nixnax 29:30de79d658f6 303 int sum=0;
nixnax 29:30de79d658f6 304 int placeHolder;
nixnax 29:30de79d658f6 305 if (len&1) {
nixnax 29:30de79d658f6 306 placeHolder = ptr[len-1]; // when length is odd zero stuff
nixnax 29:30de79d658f6 307 ptr[len-1]=0;
nixnax 29:30de79d658f6 308 }
nixnax 29:30de79d658f6 309 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 310 int hi = *ptr;
nixnax 29:30de79d658f6 311 ptr++;
nixnax 29:30de79d658f6 312 int lo = *ptr;
nixnax 29:30de79d658f6 313 ptr++;
nixnax 11:f58998c24f0b 314 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 315 sum = sum + val;
nixnax 11:f58998c24f0b 316 }
nixnax 11:f58998c24f0b 317 sum = sum + (sum>>16);
nixnax 29:30de79d658f6 318 if (len&1) {
nixnax 29:30de79d658f6 319 ptr[len-1] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 320 }
nixnax 12:db0dc91f0231 321 return ~sum;
nixnax 29:30de79d658f6 322 }
nixnax 11:f58998c24f0b 323
nixnax 29:30de79d658f6 324 void headerCheckSum()
nixnax 29:30de79d658f6 325 {
nixnax 11:f58998c24f0b 326 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 327 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 328 int sum=0;
nixnax 11:f58998c24f0b 329
nixnax 29:30de79d658f6 330 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 331 int hi = *ptr;
nixnax 29:30de79d658f6 332 ptr++;
nixnax 29:30de79d658f6 333 int lo = *ptr;
nixnax 29:30de79d658f6 334 ptr++;
nixnax 11:f58998c24f0b 335 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 336 sum = sum + val;
nixnax 11:f58998c24f0b 337 }
nixnax 11:f58998c24f0b 338 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 339 sum = ~sum;
nixnax 11:f58998c24f0b 340 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 341 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 342 }
nixnax 9:0992486d4a30 343
nixnax 29:30de79d658f6 344 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 345 {
nixnax 12:db0dc91f0231 346 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 347 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 348 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 349 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 350 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 351 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 352 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 353 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 354 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 355 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 356 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 357 char * dstAdr = ipPkt+16;
nixnax 18:3e35de1bc877 358 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 359 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 25:0b0450e1b08b 360 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 25:0b0450e1b08b 361 debug(("Ident %04x Sequence %04d ",icmpIdent,icmpSequence));
nixnax 29:30de79d658f6 362 char src[4];
nixnax 29:30de79d658f6 363 char dst[4];
nixnax 12:db0dc91f0231 364 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 365 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 366 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 367 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 368 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 369 chkSum[0]=0;
nixnax 29:30de79d658f6 370 chkSum[1]=0;
nixnax 12:db0dc91f0231 371 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 372 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 373 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 374 icmpSum[0]=0;
nixnax 29:30de79d658f6 375 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 376 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 16:cb0b80c24ba2 377 int sum = dataCheckSum( icmpType, icmpLength); // this checksum on icmp data portion
nixnax 29:30de79d658f6 378 icmpSum[0]=sum>>8;
nixnax 29:30de79d658f6 379 icmpSum[1]=sum; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 380
nixnax 16:cb0b80c24ba2 381 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 382 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 383 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 384 if (v0) {
nixnax 29:30de79d658f6 385 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 386 char ch = icmpData[i];
nixnax 29:30de79d658f6 387 if (ch>31 && ch<127) {
nixnax 29:30de79d658f6 388 debug(("%c",ch));
nixnax 29:30de79d658f6 389 } else {
nixnax 29:30de79d658f6 390 debug(("_"));
nixnax 29:30de79d658f6 391 }
nixnax 29:30de79d658f6 392 }
nixnax 29:30de79d658f6 393 debug(("\n"));
nixnax 29:30de79d658f6 394 }
nixnax 15:b0154c910143 395 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 396
nixnax 12:db0dc91f0231 397 } else {
nixnax 29:30de79d658f6 398 if (v0) {
nixnax 29:30de79d658f6 399 debug(("ICMP type=%d \n", icmpType[0]));
nixnax 29:30de79d658f6 400 }
nixnax 11:f58998c24f0b 401 }
nixnax 11:f58998c24f0b 402 }
nixnax 11:f58998c24f0b 403
nixnax 29:30de79d658f6 404 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 405 {
nixnax 29:30de79d658f6 406 if (v0) {
nixnax 29:30de79d658f6 407 debug(("IGMP type=%d \n", ppp.pkt.buf[28]));
nixnax 29:30de79d658f6 408 }
nixnax 29:30de79d658f6 409 }
nixnax 11:f58998c24f0b 410
nixnax 29:30de79d658f6 411 void dumpHeaderIP ()
nixnax 29:30de79d658f6 412 {
nixnax 26:11f4eb2663a7 413 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 414 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 415 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 416 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 417 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 418 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 419 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 420 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 421 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 422 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 423 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 424 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 425 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 426
nixnax 29:30de79d658f6 427 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 428 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 429 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 430 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 431 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 432 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 433 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 434 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 435 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 436 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 29:30de79d658f6 437 char srcIP [16];
nixnax 29:30de79d658f6 438 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 439 char dstIP [16];
nixnax 29:30de79d658f6 440 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 26:11f4eb2663a7 441 debug(("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength));
nixnax 29:30de79d658f6 442 if (v1) debug(("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP));
nixnax 29:30de79d658f6 443 }
nixnax 26:11f4eb2663a7 444
nixnax 29:30de79d658f6 445 void dumpHeaderTCP()
nixnax 29:30de79d658f6 446 {
nixnax 29:30de79d658f6 447 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 448 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 29:30de79d658f6 449 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 450 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 29:30de79d658f6 451 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 31:e000c1b9c565 452 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 453 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 26:11f4eb2663a7 454 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 455
nixnax 29:30de79d658f6 456 char flagInfo[10];
nixnax 29:30de79d658f6 457 memset(flagInfo,'.',10); // text presentation of TCP flags
nixnax 29:30de79d658f6 458 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 459 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 460 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 461 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 462 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 463 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 464 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 465 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 466 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 29:30de79d658f6 467 flagInfo[9]=0; // null terminate string
nixnax 29:30de79d658f6 468 if (v0) {
nixnax 34:8a6fbc73a7f1 469 debug(("Flags %s Seq %u Ack %u", flagInfo, seq, ack));
nixnax 29:30de79d658f6 470 }
nixnax 29:30de79d658f6 471 }
nixnax 29:30de79d658f6 472
nixnax 29:30de79d658f6 473 void tcpHandler()
nixnax 29:30de79d658f6 474 {
nixnax 26:11f4eb2663a7 475 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 476 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 477 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 478 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 479 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 480 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 481 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 482 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 483 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 484 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 485
nixnax 29:30de79d658f6 486 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 487 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 488
nixnax 29:30de79d658f6 489 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 490 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 491 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 492 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 493 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 494 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 495 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 496 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 497
nixnax 26:11f4eb2663a7 498 int tcpSize = packetLength - headerSizeIP;
nixnax 35:e7068df4d971 499 int headerSizeTCP = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 29:30de79d658f6 500
nixnax 31:e000c1b9c565 501 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 502 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 29:30de79d658f6 503
nixnax 35:e7068df4d971 504 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 29:30de79d658f6 505
nixnax 35:e7068df4d971 506 char * dataStart = ppp.pkt.buf + 4 + headerSizeIP + headerSizeTCP; // start of data block after TCP header
nixnax 35:e7068df4d971 507 int incomingLen = tcpSize - headerSizeTCP; // size of data block after TCP header
nixnax 28:1aa629be05e7 508
nixnax 29:30de79d658f6 509 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 510 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 511 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 512 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 513 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 514
nixnax 29:30de79d658f6 515 // A sparse TCP flag interpreter that implements basic TCP connections from a single source
nixnax 29:30de79d658f6 516
nixnax 35:e7068df4d971 517 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 36:2a9b457f8276 518 int flagsOut = TCP_FLAG_ACK; // the default case is an ack
nixnax 36:2a9b457f8276 519 int fastResponse = 0; // normally we wait 200ms before sending but this can make it faster
nixnax 35:e7068df4d971 520
nixnax 35:e7068df4d971 521 if ( ((flagsTCP & ~TCP_FLAG_ACK) == 0) && ((flagsTCP & TCP_FLAG_ACK) != 0) ) {
nixnax 36:2a9b457f8276 522 if (incomingLen == 0) return; // no new data
nixnax 29:30de79d658f6 523 } else if ( (flagsTCP & TCP_FLAG_FIN) != 0 ) { // got FIN
nixnax 36:2a9b457f8276 524 if ((ppp.oldFlags & TCP_FLAG_FIN) !=0) return;
nixnax 36:2a9b457f8276 525 seq++; // increase sequence by 1 for FIN and SYNC
nixnax 29:30de79d658f6 526 } else if ( (flagsTCP & TCP_FLAG_SYN) != 0 ) { // got SYN
nixnax 36:2a9b457f8276 527 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // do a syn-ack
nixnax 36:2a9b457f8276 528 seq++; // increase sequency by for FIN and SYN
nixnax 29:30de79d658f6 529 } else if ( (flagsTCP & TCP_FLAG_PSH) != 0 ) { // they are pushing data
nixnax 36:2a9b457f8276 530 fastResponse = 1; // we can response fast to a push
nixnax 35:e7068df4d971 531 // It's a push - let's check the data for an HTTP home page GET request
nixnax 31:e000c1b9c565 532 if ( strncmp(dataStart, "GET / HTTP/1.1", 14) == 0) {
nixnax 31:e000c1b9c565 533 dataLen = 15*32; // this block has to hold the web page below, but keep it under 1k
nixnax 31:e000c1b9c565 534 memset(dataStart,'x', dataLen ); // initialize the block
nixnax 35:e7068df4d971 535 int n=1; // number of bytes we have printed so far
nixnax 31:e000c1b9c565 536 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 35:e7068df4d971 537 n=n+sprintf(n+dataStart,"Content-Length: 376\r\n"); // http header
nixnax 32:512228c29209 538 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header
nixnax 31:e000c1b9c565 539 int nHeader=n; // byte total of all headers
nixnax 31:e000c1b9c565 540 n=n+sprintf(n+dataStart,"<html><head><title>mbed-PPP-Blinky</title><script>window.onload=function()"); // html
nixnax 31:e000c1b9c565 541 n=n+sprintf(n+dataStart,"{setInterval(function(){function x(){return document.getElementById('w');};"); // html
nixnax 31:e000c1b9c565 542 n=n+sprintf(n+dataStart,"x().innerText = parseInt(x().innerText)+1;},100);};</script></head><body>"); // html
nixnax 31:e000c1b9c565 543 n=n+sprintf(n+dataStart,"<h1>mbed-PPP-Blinky Up and Running</h1><h1 id=\"w\" style=\"text-align:"); // html
nixnax 31:e000c1b9c565 544 n=n+sprintf(n+dataStart," center\";>0</h1><h1><a href=\"http://bit.ly/pppBlinky\">Source on mbed</h1></body></html>"); // html
nixnax 31:e000c1b9c565 545 int contentLength = dataLen-nHeader; // this is how to calculate Content-Length, but using curl -v is easier
nixnax 31:e000c1b9c565 546 contentLength = contentLength+0; // get around unreferenced variable warning
nixnax 31:e000c1b9c565 547 if (v0) {
nixnax 35:e7068df4d971 548 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 549 }
nixnax 34:8a6fbc73a7f1 550 } else if ( strncmp(dataStart, "GET /", 4) == 0) { // all other files get 404 not found
nixnax 32:512228c29209 551 dataLen = 5*32; // this block has to hold the web page below, but keep it under 1k
nixnax 31:e000c1b9c565 552 memset(dataStart,'x', dataLen ); // initialize the block
nixnax 32:512228c29209 553 int n=0;
nixnax 32:512228c29209 554 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 32:512228c29209 555 n=n+sprintf(n+dataStart,"Content-Length: 58\r\n"); // http header
nixnax 32:512228c29209 556 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header
nixnax 32:512228c29209 557 int nHeader=n; // byte total of all headers
nixnax 32:512228c29209 558 n=n+sprintf(n+dataStart,"<html><head>"); // html
nixnax 32:512228c29209 559 n=n+sprintf(n+dataStart,"<body><h1>File Not Found</h1></body>\r\n</html>"); // html
nixnax 32:512228c29209 560 int contentLength = dataLen-nHeader; // this is how to calculate Content-Length, but using curl -v is easier
nixnax 32:512228c29209 561 contentLength = contentLength+0; // get around unreferenced variable warning
nixnax 31:e000c1b9c565 562 if (v0) {
nixnax 35:e7068df4d971 563 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 564 }
nixnax 35:e7068df4d971 565 } else {
nixnax 35:e7068df4d971 566 dataLen=0;
nixnax 29:30de79d658f6 567 }
nixnax 36:2a9b457f8276 568 } else {
nixnax 36:2a9b457f8276 569 dataLen=0;
nixnax 28:1aa629be05e7 570 }
nixnax 29:30de79d658f6 571
nixnax 35:e7068df4d971 572 // All the flag checking is now donw
nixnax 35:e7068df4d971 573
nixnax 36:2a9b457f8276 574 ppp.oldFlags = flagsTCP; // remember the flags for the next round
nixnax 36:2a9b457f8276 575
nixnax 35:e7068df4d971 576 // Now we have to recalculate all the header sizes
nixnax 29:30de79d658f6 577
nixnax 35:e7068df4d971 578 ack = seq + incomingLen; // acknowledge the number of bytes they sent by adding it to seq
nixnax 35:e7068df4d971 579 seq = ppp.seq;
nixnax 26:11f4eb2663a7 580
nixnax 29:30de79d658f6 581 char src[4];
nixnax 29:30de79d658f6 582 char dst[4];
nixnax 29:30de79d658f6 583 memcpy(src, srcAdr,4);
nixnax 29:30de79d658f6 584 memcpy(dst, dstAdr,4);
nixnax 29:30de79d658f6 585 memcpy(srcAdr, dst,4);
nixnax 29:30de79d658f6 586 memcpy(dstAdr, src,4); // swap ip address source/dest
nixnax 29:30de79d658f6 587 char psrc[2];
nixnax 29:30de79d658f6 588 char pdst[2];
nixnax 29:30de79d658f6 589 memcpy(psrc, srctcp,2);
nixnax 29:30de79d658f6 590 memcpy(pdst, dsttcp,2);
nixnax 29:30de79d658f6 591 memcpy(srctcp, pdst,2);
nixnax 29:30de79d658f6 592 memcpy(dsttcp, psrc,2); // swap ip port source/dest
nixnax 29:30de79d658f6 593
nixnax 36:2a9b457f8276 594
nixnax 36:2a9b457f8276 595 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen;
nixnax 36:2a9b457f8276 596 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 597 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 598 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 599 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 600
nixnax 36:2a9b457f8276 601 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 36:2a9b457f8276 602
nixnax 36:2a9b457f8276 603 acktcp[0]=ack>>24;
nixnax 36:2a9b457f8276 604 acktcp[1]=ack>>16;
nixnax 36:2a9b457f8276 605 acktcp[2]=ack>>8;
nixnax 36:2a9b457f8276 606 acktcp[3]=ack>>0; // save ack
nixnax 36:2a9b457f8276 607 seqtcp[0]=seq>>24;
nixnax 36:2a9b457f8276 608 seqtcp[1]=seq>>16;
nixnax 36:2a9b457f8276 609 seqtcp[2]=seq>>8;
nixnax 36:2a9b457f8276 610 seqtcp[3]=seq>>0; // save seq
nixnax 36:2a9b457f8276 611
nixnax 36:2a9b457f8276 612
nixnax 36:2a9b457f8276 613 // redo all the header stuff
nixnax 36:2a9b457f8276 614
nixnax 29:30de79d658f6 615 headercheck[0]=0;
nixnax 29:30de79d658f6 616 headercheck[1]=0;
nixnax 29:30de79d658f6 617 headerCheckSum(); // redo the ip header checksum
nixnax 29:30de79d658f6 618 char pseudoHeader[12];
nixnax 29:30de79d658f6 619 int sum;
nixnax 29:30de79d658f6 620 char temp[12]; // for the terrible pseudoheader checksum
nixnax 26:11f4eb2663a7 621 memcpy( pseudoHeader+0, srcAdr, 8); // source and destination addresses.
nixnax 29:30de79d658f6 622 pseudoHeader[8]=0;
nixnax 29:30de79d658f6 623 pseudoHeader[9]=protocol[0];
nixnax 29:30de79d658f6 624 pseudoHeader[10]=tcpSize>>8;
nixnax 29:30de79d658f6 625 pseudoHeader[11]=tcpSize;
nixnax 26:11f4eb2663a7 626 memcpy(temp, s-12, 12); // keep a copy
nixnax 26:11f4eb2663a7 627 memcpy( s-12, pseudoHeader, 12); // put the header on the tcp packet
nixnax 29:30de79d658f6 628 checksumtcp[0]=0;
nixnax 29:30de79d658f6 629 checksumtcp[1]=0;
nixnax 29:30de79d658f6 630 sum=dataCheckSum(s-12,tcpSize+12); // update TCP checksum
nixnax 29:30de79d658f6 631 checksumtcp[0]=sum>>8;
nixnax 29:30de79d658f6 632 checksumtcp[1]=sum;
nixnax 26:11f4eb2663a7 633 memcpy( s-12, temp, 12); // overwrite the pseudoheader
nixnax 36:2a9b457f8276 634 if (fastResponse==1) {
nixnax 36:2a9b457f8276 635 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 636 } else {
nixnax 36:2a9b457f8276 637 wait(0.2); // wait 200 ms before sending packet
nixnax 36:2a9b457f8276 638 }
nixnax 26:11f4eb2663a7 639 sendFrame(); // return the TCP packet
nixnax 35:e7068df4d971 640 ppp.seq = ppp.seq + dataLen; // increase OUR sequence by outgoing data length - for the next round
nixnax 29:30de79d658f6 641 }
nixnax 26:11f4eb2663a7 642
nixnax 29:30de79d658f6 643 void dumpDataTCP()
nixnax 29:30de79d658f6 644 {
nixnax 26:11f4eb2663a7 645 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 646 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 647 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 648 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 649 if (v1) {
nixnax 35:e7068df4d971 650 debug(("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen)); // 1 for more verbose
nixnax 29:30de79d658f6 651 }
nixnax 29:30de79d658f6 652 if (dataLen > 0) {
nixnax 35:e7068df4d971 653 debug(("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP)); // show the data
nixnax 29:30de79d658f6 654 }
nixnax 29:30de79d658f6 655 }
nixnax 26:11f4eb2663a7 656
nixnax 29:30de79d658f6 657 void TCPpacket()
nixnax 29:30de79d658f6 658 {
nixnax 26:11f4eb2663a7 659 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 660 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 661 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 662 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 663 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 664 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 665 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 666 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 667 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 668 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 669 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 670 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 671 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 672
nixnax 29:30de79d658f6 673 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 674 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 675 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 676 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 677 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 678 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 679 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 680 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 681 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 682 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 29:30de79d658f6 683 char srcIP [16];
nixnax 29:30de79d658f6 684 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 685 char dstIP [16];
nixnax 29:30de79d658f6 686 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 687 if (v0) {
nixnax 29:30de79d658f6 688 debug(("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength));
nixnax 29:30de79d658f6 689 }
nixnax 29:30de79d658f6 690 if (v0) {
nixnax 29:30de79d658f6 691 debug(("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP));
nixnax 29:30de79d658f6 692 }
nixnax 28:1aa629be05e7 693 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 694 dumpDataTCP();
nixnax 26:11f4eb2663a7 695 tcpHandler();
nixnax 11:f58998c24f0b 696 }
nixnax 11:f58998c24f0b 697
nixnax 29:30de79d658f6 698 void otherProtocol()
nixnax 29:30de79d658f6 699 {
nixnax 29:30de79d658f6 700 debug(("Other IP protocol"));
nixnax 29:30de79d658f6 701 }
nixnax 26:11f4eb2663a7 702
nixnax 29:30de79d658f6 703 void IPframe()
nixnax 29:30de79d658f6 704 {
nixnax 10:74f8233f72c0 705 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 706 switch (protocol) {
nixnax 29:30de79d658f6 707 case 1:
nixnax 29:30de79d658f6 708 ICMPpacket();
nixnax 29:30de79d658f6 709 break;
nixnax 29:30de79d658f6 710 case 2:
nixnax 29:30de79d658f6 711 IGMPpacket();
nixnax 29:30de79d658f6 712 break;
nixnax 29:30de79d658f6 713 case 17:
nixnax 29:30de79d658f6 714 UDPpacket();
nixnax 29:30de79d658f6 715 break;
nixnax 29:30de79d658f6 716 case 6:
nixnax 29:30de79d658f6 717 TCPpacket();
nixnax 29:30de79d658f6 718 break;
nixnax 29:30de79d658f6 719 default:
nixnax 29:30de79d658f6 720 otherProtocol();
nixnax 29:30de79d658f6 721 }
nixnax 29:30de79d658f6 722 }
nixnax 9:0992486d4a30 723
nixnax 29:30de79d658f6 724 void LCPconfReq()
nixnax 29:30de79d658f6 725 {
nixnax 15:b0154c910143 726 debug(("LCP Config "));
nixnax 9:0992486d4a30 727 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 728 ppp.pkt.buf[4]=4; // allow only no options
nixnax 15:b0154c910143 729 debug(("Reject\n"));
nixnax 29:30de79d658f6 730 sendFrame();
nixnax 9:0992486d4a30 731 } else {
nixnax 9:0992486d4a30 732 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 15:b0154c910143 733 debug(("Ack\n"));
nixnax 9:0992486d4a30 734 sendFrame();
nixnax 15:b0154c910143 735 debug(("LCP Ask\n"));
nixnax 11:f58998c24f0b 736 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 737 sendFrame();
nixnax 9:0992486d4a30 738 }
nixnax 9:0992486d4a30 739 }
nixnax 9:0992486d4a30 740
nixnax 29:30de79d658f6 741 void LCPconfAck()
nixnax 29:30de79d658f6 742 {
nixnax 15:b0154c910143 743 debug(("LCP Ack\n"));
nixnax 29:30de79d658f6 744 }
nixnax 9:0992486d4a30 745
nixnax 29:30de79d658f6 746 void LCPend()
nixnax 29:30de79d658f6 747 {
nixnax 29:30de79d658f6 748 debug(("LCP End\n"));
nixnax 29:30de79d658f6 749 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 750 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 751 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 752 }
nixnax 9:0992486d4a30 753
nixnax 29:30de79d658f6 754 void LCPother()
nixnax 29:30de79d658f6 755 {
nixnax 29:30de79d658f6 756 debug(("LCP Other\n"));
nixnax 29:30de79d658f6 757 dumpFrame();
nixnax 29:30de79d658f6 758 }
nixnax 29:30de79d658f6 759
nixnax 29:30de79d658f6 760 void LCPframe()
nixnax 29:30de79d658f6 761 {
nixnax 29:30de79d658f6 762 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 763 switch (code) {
nixnax 29:30de79d658f6 764 case 1:
nixnax 29:30de79d658f6 765 LCPconfReq();
nixnax 29:30de79d658f6 766 break; // config request
nixnax 29:30de79d658f6 767 case 2:
nixnax 29:30de79d658f6 768 LCPconfAck();
nixnax 29:30de79d658f6 769 break; // config ack
nixnax 29:30de79d658f6 770 case 5:
nixnax 29:30de79d658f6 771 LCPend();
nixnax 29:30de79d658f6 772 break; // end connection
nixnax 29:30de79d658f6 773 default:
nixnax 29:30de79d658f6 774 LCPother();
nixnax 29:30de79d658f6 775 }
nixnax 9:0992486d4a30 776 }
nixnax 9:0992486d4a30 777
nixnax 29:30de79d658f6 778 void discardedFrame()
nixnax 29:30de79d658f6 779 {
nixnax 29:30de79d658f6 780 if (v0) {
nixnax 29:30de79d658f6 781 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 782 }
nixnax 9:0992486d4a30 783 }
nixnax 9:0992486d4a30 784
nixnax 29:30de79d658f6 785 void determinePacketType()
nixnax 29:30de79d658f6 786 {
nixnax 29:30de79d658f6 787 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 29:30de79d658f6 788 debug(("byte0 != ff\n"));
nixnax 29:30de79d658f6 789 return;
nixnax 29:30de79d658f6 790 }
nixnax 29:30de79d658f6 791 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 29:30de79d658f6 792 debug(("byte1 != 3\n"));
nixnax 29:30de79d658f6 793 return;
nixnax 29:30de79d658f6 794 }
nixnax 29:30de79d658f6 795 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 29:30de79d658f6 796 debug(("byte2 != 21\n"));
nixnax 29:30de79d658f6 797 return;
nixnax 29:30de79d658f6 798 }
nixnax 9:0992486d4a30 799 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 800 switch (packetType) {
nixnax 29:30de79d658f6 801 case 0xc0:
nixnax 29:30de79d658f6 802 LCPframe();
nixnax 29:30de79d658f6 803 break; // link control
nixnax 29:30de79d658f6 804 case 0x80:
nixnax 29:30de79d658f6 805 IPCPframe();
nixnax 29:30de79d658f6 806 break; // IP control
nixnax 29:30de79d658f6 807 case 0x00:
nixnax 29:30de79d658f6 808 IPframe();
nixnax 29:30de79d658f6 809 break; // IP itself
nixnax 29:30de79d658f6 810 default:
nixnax 29:30de79d658f6 811 discardedFrame();
nixnax 9:0992486d4a30 812 }
nixnax 29:30de79d658f6 813 }
nixnax 9:0992486d4a30 814
nixnax 29:30de79d658f6 815 void scanForConnectString()
nixnax 29:30de79d658f6 816 {
nixnax 9:0992486d4a30 817 if ( ppp.online==0 ) {
nixnax 15:b0154c910143 818 char * clientFound = strstr( (char *)rxbuf, "CLIENTCLIENT" ); // look for PC string
nixnax 29:30de79d658f6 819 if( clientFound ) {
nixnax 9:0992486d4a30 820 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't get fixated
nixnax 9:0992486d4a30 821 pc.printf("CLIENTSERVER"); // respond to PC
nixnax 9:0992486d4a30 822 ppp.online=1; // we can stop looking for the string
nixnax 15:b0154c910143 823 debug(("Connect string found\n"));
nixnax 9:0992486d4a30 824 }
nixnax 9:0992486d4a30 825 }
nixnax 9:0992486d4a30 826 }
nixnax 9:0992486d4a30 827
nixnax 0:2cf4880c312a 828 int main()
nixnax 0:2cf4880c312a 829 {
nixnax 14:c65831c25aaa 830 pc.baud(115200); // USB virtual serial port
nixnax 15:b0154c910143 831 xx.baud(115200); // second serial port for debug(((((((( messages
nixnax 9:0992486d4a30 832 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 29:30de79d658f6 833
nixnax 9:0992486d4a30 834 pppInitStruct(); // initialize all the PPP properties
nixnax 4:a469050d5b80 835
nixnax 9:0992486d4a30 836 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 4:a469050d5b80 837
nixnax 29:30de79d658f6 838 int frameStartIndex, frameEndIndex;
nixnax 29:30de79d658f6 839 int frameBusy=0;
nixnax 4:a469050d5b80 840
nixnax 0:2cf4880c312a 841 while(1) {
nixnax 9:0992486d4a30 842 if ( ppp.online==0 ) scanForConnectString(); // try to connect
nixnax 22:00df34cd4d7e 843 while ( rxbufNotEmpty() ) {
nixnax 1:9e03798d4367 844 int rx = pc_getBuf();
nixnax 29:30de79d658f6 845 if (frameBusy) {
nixnax 4:a469050d5b80 846 if (rx==FRAME_7E) {
nixnax 4:a469050d5b80 847 frameBusy=0; // done gathering frame
nixnax 4:a469050d5b80 848 frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 4:a469050d5b80 849 processFrame(frameStartIndex, frameEndIndex);
nixnax 4:a469050d5b80 850 }
nixnax 29:30de79d658f6 851 } else {
nixnax 4:a469050d5b80 852 if (rx==FRAME_7E) {
nixnax 4:a469050d5b80 853 frameBusy=1; // start gathering frame
nixnax 9:0992486d4a30 854 frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 4:a469050d5b80 855 }
nixnax 0:2cf4880c312a 856 }
nixnax 4:a469050d5b80 857 }
nixnax 7:ab147f5e97ac 858 }
nixnax 7:ab147f5e97ac 859 }