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@44:d0c61ae49ea5, 2017-01-18 (annotated)

Committer:
nixnax
Date:
Wed Jan 18 19:06:41 2017 +0000
Revision:
44:d0c61ae49ea5
Parent:
43:aa57db08995d
Child:
45:ed9112b1734c
Automatic Content-Length; Avoid sending Null at the end of sprintf string

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 0:2cf4880c312a 1 #include "mbed.h"
nixnax 0:2cf4880c312a 2
nixnax 29:30de79d658f6 3 // Copyright 2016 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax 12:db0dc91f0231 4
nixnax 41:e58a5a09f411 5 // PPP-Blinky - "My Internet Of Thing"
nixnax 41:e58a5a09f411 6 // A Tiny Webserver Using Windows XP/7/8/10 Networking Over A Serial Port.
nixnax 0:2cf4880c312a 7
nixnax 41:e58a5a09f411 8 // Also receives UDP packets and responds to ping (ICMP Echo requests)
nixnax 4:a469050d5b80 9
nixnax 41:e58a5a09f411 10 // Notes and Instructions
nixnax 41:e58a5a09f411 11 // http://bit.ly/PPP-Blinky-Instructions
nixnax 0:2cf4880c312a 12
nixnax 41:e58a5a09f411 13 // Handy reading material
nixnax 6:fba4c2e817b8 14 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 15 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 39:b90183d35f1e 16 // http://bit.ly/dialup777error - how to solve Dial Up Error 777 in Windows 7/8/10
nixnax 41:e58a5a09f411 17 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 18
nixnax 29:30de79d658f6 19 // Handy tools
nixnax 44:d0c61ae49ea5 20 // https://ttssh2.osdn.jp/index.html.en - Tera Term, a good terminal program to monitor the debug output from the second serial port with!
nixnax 44:d0c61ae49ea5 21 // Wireshark - can't monitor Dial-Up network packets on windows, but useful - can import our dumpFrame routine's hex output
nixnax 29:30de79d658f6 22 // Microsoft network monitor - real-time monitoring of all our packets
nixnax 29:30de79d658f6 23 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 29:30de79d658f6 24 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE)
nixnax 41:e58a5a09f411 25 // The curl.exe program in Windows Powershell - use it like this to stress test the webserver: while (1) { curl 172.10.10.1 }
nixnax 29:30de79d658f6 26 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 41:e58a5a09f411 27 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from PPP-Blinky
nixnax 41:e58a5a09f411 28
nixnax 44:d0c61ae49ea5 29 // The #define below enables/disables a second serial port that prints out interesting diagnostic messages.
nixnax 44:d0c61ae49ea5 30
nixnax 44:d0c61ae49ea5 31 //#define SERIAL_PORT_MONITOR_YES
nixnax 44:d0c61ae49ea5 32 #define SERIAL_PORT_MONITOR_NO
nixnax 0:2cf4880c312a 33
nixnax 41:e58a5a09f411 34 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 44:d0c61ae49ea5 35 Serial xx(PC_10, PC_11); // Not needed to run - if you want to see this change SERIAL_PORT_MONITOR_NO to SERIAL_PORT_MONITOR_YES
nixnax 42:4de44be70bfd 36 #define debug(x...) xx.printf (x)
nixnax 41:e58a5a09f411 37 #else
nixnax 41:e58a5a09f411 38 // no debug monitoring
nixnax 42:4de44be70bfd 39 #define debug(x...) {}
nixnax 41:e58a5a09f411 40 #endif
nixnax 41:e58a5a09f411 41
nixnax 41:e58a5a09f411 42 Serial pc(USBTX, USBRX); // The serial port on your mbed hardware. Your PC thinks this is a dial-up modem.
nixnax 29:30de79d658f6 43
nixnax 29:30de79d658f6 44 int v0=1;
nixnax 29:30de79d658f6 45 int v1=1; // verbosity flags used in debug printouts - change to 1/0 to see more/less debug info
nixnax 29:30de79d658f6 46
nixnax 29:30de79d658f6 47 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 48
nixnax 29:30de79d658f6 49 // the standard hdlc frame start/end character
nixnax 4:a469050d5b80 50 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 51
nixnax 29:30de79d658f6 52 // the serial port receive buffer and packet buffer
nixnax 29:30de79d658f6 53 #define BUFLEN (1<<12)
nixnax 20:5db9b77b38a6 54 char rxbuf[BUFLEN];
nixnax 41:e58a5a09f411 55 char frbuf[2000]; // send/receive buffer for ppp frames
nixnax 0:2cf4880c312a 56
nixnax 29:30de79d658f6 57 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 58 struct pppType {
nixnax 38:ab582987926e 59 int online; // we hunt for a PPP connection if this is zero
nixnax 38:ab582987926e 60 int ident; // our IP ident value
nixnax 38:ab582987926e 61 unsigned int seq; // our TCP sequence number
nixnax 38:ab582987926e 62 int crc; // for calculating IP and TCP CRCs
nixnax 38:ab582987926e 63 int ledState; // state of LED1
nixnax 4:a469050d5b80 64 struct {
nixnax 20:5db9b77b38a6 65 char * buf;
nixnax 29:30de79d658f6 66 volatile int head;
nixnax 29:30de79d658f6 67 volatile int tail;
nixnax 38:ab582987926e 68 } rx; // serial port objects
nixnax 4:a469050d5b80 69 struct {
nixnax 38:ab582987926e 70 int len; // number of bytes in buffer
nixnax 38:ab582987926e 71 int crc; // PPP CRC (frame check)
nixnax 38:ab582987926e 72 char * buf; // the actual buffer
nixnax 38:ab582987926e 73 } pkt; // ppp buffer objects
nixnax 29:30de79d658f6 74 };
nixnax 31:e000c1b9c565 75
nixnax 29:30de79d658f6 76 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 77
nixnax 29:30de79d658f6 78 // intitialize our globals
nixnax 29:30de79d658f6 79 void pppInitStruct()
nixnax 29:30de79d658f6 80 {
nixnax 29:30de79d658f6 81 ppp.online=0;
nixnax 29:30de79d658f6 82 ppp.rx.buf=rxbuf;
nixnax 29:30de79d658f6 83 ppp.rx.tail=0;
nixnax 29:30de79d658f6 84 ppp.rx.head=0;
nixnax 29:30de79d658f6 85 ppp.pkt.buf=frbuf;
nixnax 29:30de79d658f6 86 ppp.pkt.len=0;
nixnax 29:30de79d658f6 87 ppp.ident=0;
nixnax 35:e7068df4d971 88 ppp.seq=1000;
nixnax 29:30de79d658f6 89 ppp.ledState=0;
nixnax 29:30de79d658f6 90 }
nixnax 26:11f4eb2663a7 91
nixnax 43:aa57db08995d 92 void led1Toggle()
nixnax 43:aa57db08995d 93 {
nixnax 43:aa57db08995d 94 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 43:aa57db08995d 95 led1 = ppp.ledState;
nixnax 43:aa57db08995d 96 }
nixnax 43:aa57db08995d 97
nixnax 29:30de79d658f6 98 void crcReset()
nixnax 29:30de79d658f6 99 {
nixnax 29:30de79d658f6 100 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 101 }
nixnax 4:a469050d5b80 102
nixnax 29:30de79d658f6 103 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 104 {
nixnax 29:30de79d658f6 105 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 106 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 107 x>>=1;
nixnax 29:30de79d658f6 108 }
nixnax 29:30de79d658f6 109 }
nixnax 29:30de79d658f6 110
nixnax 29:30de79d658f6 111 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 112 {
nixnax 31:e000c1b9c565 113 crcReset();
nixnax 31:e000c1b9c565 114 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 115 return ppp.crc;
nixnax 29:30de79d658f6 116 }
nixnax 0:2cf4880c312a 117
nixnax 0:2cf4880c312a 118 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 119 {
nixnax 17:4918c893d802 120 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 121 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 122 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 123 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 124 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 125 }
nixnax 0:2cf4880c312a 126 }
nixnax 0:2cf4880c312a 127
nixnax 22:00df34cd4d7e 128 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 129 {
nixnax 22:00df34cd4d7e 130 __disable_irq(); // critical section start
nixnax 43:aa57db08995d 131 int emptyStatus = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 132 __enable_irq(); // critical section end
nixnax 43:aa57db08995d 133 return emptyStatus;
nixnax 0:2cf4880c312a 134 }
nixnax 0:2cf4880c312a 135
nixnax 0:2cf4880c312a 136 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 137 {
nixnax 22:00df34cd4d7e 138 if ( rxbufNotEmpty() ) {
nixnax 4:a469050d5b80 139 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 20:5db9b77b38a6 140 __disable_irq(); // critical section start
nixnax 29:30de79d658f6 141 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 20:5db9b77b38a6 142 __enable_irq(); // critical section end
nixnax 0:2cf4880c312a 143 return x;
nixnax 20:5db9b77b38a6 144 } else return -1;
nixnax 0:2cf4880c312a 145 }
nixnax 0:2cf4880c312a 146
nixnax 29:30de79d658f6 147 void processFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 148 {
nixnax 38:ab582987926e 149 led1Toggle(); // change led1 state on every frame we receive
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 42:4de44be70bfd 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 38:ab582987926e 187 // Note - the hex output of dumpFrame() can be imported into WireShark
nixnax 38:ab582987926e 188 // Capture the frame's hex output in your terminal program and save as a text file
nixnax 38:ab582987926e 189 // In WireShark, use "Import Hex File". Options are: Offset=None, Protocol=PPP.
nixnax 29:30de79d658f6 190 void dumpFrame()
nixnax 29:30de79d658f6 191 {
nixnax 42:4de44be70bfd 192 for(int i=0; i<ppp.pkt.len; i++) debug("%02x ", ppp.pkt.buf[i]);
nixnax 42:4de44be70bfd 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 38:ab582987926e 200 pc.putc(ch^0x20); // three characters need special handling
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 38:ab582987926e 206 void sendFrame() // send one PPP frame in HDLC format
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 42:4de44be70bfd 283 if(v1) debug("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort);
nixnax 42:4de44be70bfd 284 if(v1) debug("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort);
nixnax 42:4de44be70bfd 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 42:4de44be70bfd 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 38:ab582987926e 306 placeHolder = ptr[len-1]; // when length is odd stuff in a zero byte
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 42:4de44be70bfd 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 42:4de44be70bfd 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 42:4de44be70bfd 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 42:4de44be70bfd 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 42:4de44be70bfd 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 42:4de44be70bfd 441 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 442 if (v0) 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 42:4de44be70bfd 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 38:ab582987926e 515 // A sparse TCP flag interpreter that implements simple TCP connections from a single source
nixnax 38:ab582987926e 516 // Clients are allowed ONE push packet, after which the link is closed with a FIN flag in the ACK packet
nixnax 38:ab582987926e 517 // This strategy allows web browsers, netcat and curl to work ok while keeping the state machine simple
nixnax 29:30de79d658f6 518
nixnax 35:e7068df4d971 519 int dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 38:ab582987926e 520 int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
nixnax 38:ab582987926e 521 int fastResponse = 0; // normally you wait 200ms before sending a packet but this can make it faster
nixnax 38:ab582987926e 522
nixnax 38:ab582987926e 523 if (ppp.seq != ack) {
nixnax 38:ab582987926e 524 ppp.seq = ack; // if their sequence number is different than our calculation we adopt their version
nixnax 38:ab582987926e 525 }
nixnax 35:e7068df4d971 526
nixnax 35:e7068df4d971 527 if ( ((flagsTCP & ~TCP_FLAG_ACK) == 0) && ((flagsTCP & TCP_FLAG_ACK) != 0) ) {
nixnax 38:ab582987926e 528 if (incomingLen == 0) { // ignore - just an empty ack packet
nixnax 38:ab582987926e 529 return;
nixnax 38:ab582987926e 530 }
nixnax 38:ab582987926e 531 } else if ( (flagsTCP & TCP_FLAG_SYN) != 0 ) { // got SYN flag
nixnax 36:2a9b457f8276 532 flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // do a syn-ack
nixnax 38:ab582987926e 533 seq++; // for SYN flag we have to increase sequence by 1
nixnax 38:ab582987926e 534 } else if ( (flagsTCP & TCP_FLAG_FIN) != 0 ) { // got FIN flag
nixnax 38:ab582987926e 535 seq++; // for FIN flag we have to increase sequence by 1
nixnax 38:ab582987926e 536 } else if ( (flagsTCP & TCP_FLAG_PSH) != 0 ) { // got PSH flag (push)
nixnax 38:ab582987926e 537 flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // for every push we answer once AND close the link
nixnax 38:ab582987926e 538 fastResponse = 1; // we can respond fast to a push
nixnax 38:ab582987926e 539 // It's a push, so let's check the incoming data for an HTTP GET request
nixnax 31:e000c1b9c565 540 if ( strncmp(dataStart, "GET / HTTP/1.1", 14) == 0) {
nixnax 44:d0c61ae49ea5 541 dataLen = 32*32; // this block has to hold the web page below, but keep it under 1024 or increase this
nixnax 38:ab582987926e 542 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 44:d0c61ae49ea5 543
nixnax 38:ab582987926e 544 int n=0; // number of bytes we have printed so far
nixnax 31:e000c1b9c565 545 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 44:d0c61ae49ea5 546 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 44:d0c61ae49ea5 547 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 44:d0c61ae49ea5 548 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 44:d0c61ae49ea5 549 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header must end with empty line (\r\n)
nixnax 31:e000c1b9c565 550 int nHeader=n; // byte total of all headers
nixnax 44:d0c61ae49ea5 551
nixnax 44:d0c61ae49ea5 552 n=n+sprintf(n+dataStart,"<!DOCTYPE html>\n<html><head><title>mbed-PPP-Blinky</title>\n<script>window.onload=function()"); // html start
nixnax 44:d0c61ae49ea5 553 n=n+sprintf(n+dataStart,"{setInterval(function(){function x(){return document.getElementById('w');};\n"); // html
nixnax 44:d0c61ae49ea5 554 n=n+sprintf(n+dataStart,"x().textContent = parseInt(x().textContent)+1;},100);};</script></head>\n<body style=\"font-size:30px; color:#807070\">"); // html
nixnax 44:d0c61ae49ea5 555 n=n+sprintf(n+dataStart,"<h1>mbed PPP-Blinky Up and Running</h1>\n<h1 id=\"w\" style=\"text-align:"); // html
nixnax 44:d0c61ae49ea5 556 n=n+sprintf(n+dataStart," center;\">0</h1><h1><a href=\"http://bit.ly/pppBlink2\">Source on mbed</a></h1>\n</body></html>\n"); // html end
nixnax 44:d0c61ae49ea5 557
nixnax 44:d0c61ae49ea5 558 int contentLength = n-nHeader; // Content-Length is the count of every character after the header
nixnax 44:d0c61ae49ea5 559 int cSize = 5; // maximum number of digits we allow for Content-Length
nixnax 44:d0c61ae49ea5 560 char contentLengthString[cSize+1]; // temporary buffer to create Content-Length string
nixnax 44:d0c61ae49ea5 561 snprintf(contentLengthString,cSize+1,"%*d",cSize,contentLength); // print Content-Length with leading spaces and fixed width = csize
nixnax 44:d0c61ae49ea5 562 memcpy(dataStart+contentLengthStart, contentLengthString, cSize); // copy Content-Length to the send buffer
nixnax 44:d0c61ae49ea5 563
nixnax 31:e000c1b9c565 564 if (v0) {
nixnax 44:d0c61ae49ea5 565 debug("HTTP GET BufferSize %d*32=%d Header %d Content-Length %d Total %d Available %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n);
nixnax 31:e000c1b9c565 566 }
nixnax 44:d0c61ae49ea5 567 dataLen=n; // update the buffer size
nixnax 38:ab582987926e 568 } else if ( strncmp(dataStart, "GET /", 4) == 0) { // all other HTTP GET requests get 404 Not Found response
nixnax 44:d0c61ae49ea5 569 dataLen = 32*32; // maximum size for File not found webpage
nixnax 38:ab582987926e 570 memset(dataStart,'x', dataLen ); // initialize the data block
nixnax 44:d0c61ae49ea5 571
nixnax 38:ab582987926e 572 int n=0; // number of bytes we have printed so far
nixnax 41:e58a5a09f411 573 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 44:d0c61ae49ea5 574 n=n+sprintf(n+dataStart,"Content-Length: "); // http header
nixnax 44:d0c61ae49ea5 575 int contentLengthStart = n; // remember where Content-Length is in buffer
nixnax 44:d0c61ae49ea5 576 n=n+sprintf(n+dataStart,"?????\r\n"); // leave five spaces for content length - will be updated later
nixnax 44:d0c61ae49ea5 577 n=n+sprintf(n+dataStart,"Content-Type: text/html; charset=us-ascii\r\n\r\n"); // http header must end with empty line (\r\n)
nixnax 32:512228c29209 578 int nHeader=n; // byte total of all headers
nixnax 44:d0c61ae49ea5 579
nixnax 44:d0c61ae49ea5 580 n=n+sprintf(n+dataStart,"<!DOCTYPE html><html><head></head>"); // html start
nixnax 44:d0c61ae49ea5 581 n=n+sprintf(n+dataStart,"<body><h1>File Not Found</h1></body>");
nixnax 44:d0c61ae49ea5 582 n=n+sprintf(n+dataStart,"</html>\n"); // html end
nixnax 44:d0c61ae49ea5 583
nixnax 44:d0c61ae49ea5 584 int contentLength = n-nHeader; // Content-Length is the count of every character after the header
nixnax 44:d0c61ae49ea5 585 int cSize = 5; // maximum number of digits we allow for Content-Length
nixnax 44:d0c61ae49ea5 586 char contentLengthString[cSize+1]; // temporary buffer to create Content-Length string
nixnax 44:d0c61ae49ea5 587 snprintf(contentLengthString,cSize+1,"%*d",cSize,contentLength); // print Content-Length with leading spaces and fixed width = csize
nixnax 44:d0c61ae49ea5 588 memcpy(dataStart+contentLengthStart, contentLengthString, cSize); // copy Content-Length to the send buffer
nixnax 44:d0c61ae49ea5 589
nixnax 31:e000c1b9c565 590 if (v0) {
nixnax 44:d0c61ae49ea5 591 debug("HTTP GET BufSize %d*32=%d Header %d Content-Length %d Total %d Available %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n);
nixnax 31:e000c1b9c565 592 }
nixnax 44:d0c61ae49ea5 593 dataLen=n; // update the buffer size
nixnax 35:e7068df4d971 594 } else {
nixnax 38:ab582987926e 595 dataLen=0; // we did not find a valid HTTP request, so just ACK with zero data
nixnax 29:30de79d658f6 596 }
nixnax 36:2a9b457f8276 597 } else {
nixnax 38:ab582987926e 598 dataLen=0; // it's not any TCP Flag Combo that needs special handling
nixnax 28:1aa629be05e7 599 }
nixnax 29:30de79d658f6 600
nixnax 38:ab582987926e 601 // All the TCP flag handling is now done
nixnax 29:30de79d658f6 602
nixnax 38:ab582987926e 603 // 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 604
nixnax 38:ab582987926e 605 char src[4]; // temp hold
nixnax 38:ab582987926e 606 char dst[4]; // temp hold
nixnax 29:30de79d658f6 607 memcpy(src, srcAdr,4);
nixnax 29:30de79d658f6 608 memcpy(dst, dstAdr,4);
nixnax 29:30de79d658f6 609 memcpy(srcAdr, dst,4);
nixnax 29:30de79d658f6 610 memcpy(dstAdr, src,4); // swap ip address source/dest
nixnax 38:ab582987926e 611
nixnax 38:ab582987926e 612 char psrc[2]; // temp hold
nixnax 38:ab582987926e 613 char pdst[2]; // temp hold
nixnax 29:30de79d658f6 614 memcpy(psrc, srctcp,2);
nixnax 29:30de79d658f6 615 memcpy(pdst, dsttcp,2);
nixnax 29:30de79d658f6 616 memcpy(srctcp, pdst,2);
nixnax 29:30de79d658f6 617 memcpy(dsttcp, psrc,2); // swap ip port source/dest
nixnax 29:30de79d658f6 618
nixnax 38:ab582987926e 619 ack = seq + incomingLen; // acknowledge the number of bytes that they sent by adding it to "our" sequence number
nixnax 38:ab582987926e 620 seq = ppp.seq; // set up the sequence number we have to respond with
nixnax 38:ab582987926e 621
nixnax 38:ab582987926e 622 acktcp[0]=ack>>24;
nixnax 38:ab582987926e 623 acktcp[1]=ack>>16;
nixnax 38:ab582987926e 624 acktcp[2]=ack>>8;
nixnax 38:ab582987926e 625 acktcp[3]=ack>>0; // save ack
nixnax 38:ab582987926e 626
nixnax 38:ab582987926e 627 seqtcp[0]=seq>>24;
nixnax 38:ab582987926e 628 seqtcp[1]=seq>>16;
nixnax 38:ab582987926e 629 seqtcp[2]=seq>>8;
nixnax 38:ab582987926e 630 seqtcp[3]=seq>>0; // save seq
nixnax 38:ab582987926e 631
nixnax 38:ab582987926e 632 flagbitstcp[1] = flagsOut; // set up the new flags
nixnax 38:ab582987926e 633
nixnax 38:ab582987926e 634 int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
nixnax 36:2a9b457f8276 635 pktLen[0] = (newPacketSize>>8);
nixnax 36:2a9b457f8276 636 pktLen[1]=newPacketSize; // ip total packet size
nixnax 36:2a9b457f8276 637 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 36:2a9b457f8276 638 tcpSize = headerSizeTCP + dataLen; // tcp packet size
nixnax 36:2a9b457f8276 639
nixnax 38:ab582987926e 640 // the header is all set up, now do the IP and TCP checksums
nixnax 36:2a9b457f8276 641
nixnax 29:30de79d658f6 642 headercheck[0]=0;
nixnax 29:30de79d658f6 643 headercheck[1]=0;
nixnax 29:30de79d658f6 644 headerCheckSum(); // redo the ip header checksum
nixnax 38:ab582987926e 645
nixnax 38:ab582987926e 646 char pseudoHeader[12]; // we are building a fake TCP header
nixnax 29:30de79d658f6 647 int sum;
nixnax 26:11f4eb2663a7 648 memcpy( pseudoHeader+0, srcAdr, 8); // source and destination addresses.
nixnax 29:30de79d658f6 649 pseudoHeader[8]=0;
nixnax 29:30de79d658f6 650 pseudoHeader[9]=protocol[0];
nixnax 29:30de79d658f6 651 pseudoHeader[10]=tcpSize>>8;
nixnax 29:30de79d658f6 652 pseudoHeader[11]=tcpSize;
nixnax 38:ab582987926e 653 char temp[12]; // temporary storage for the 12 bytes that are in the way
nixnax 38:ab582987926e 654 memcpy(temp, s-12, 12); // save the 12 bytes that are in the way
nixnax 38:ab582987926e 655 memcpy( s-12, pseudoHeader, 12); // copy in the fake header
nixnax 29:30de79d658f6 656 checksumtcp[0]=0;
nixnax 29:30de79d658f6 657 checksumtcp[1]=0;
nixnax 38:ab582987926e 658 sum=dataCheckSum(s-12,tcpSize+12); // calculate the TCP checksum
nixnax 29:30de79d658f6 659 checksumtcp[0]=sum>>8;
nixnax 29:30de79d658f6 660 checksumtcp[1]=sum;
nixnax 38:ab582987926e 661 memcpy( s-12, temp, 12); // restore the 12 bytes that the fake header overwrote
nixnax 36:2a9b457f8276 662 if (fastResponse==1) {
nixnax 36:2a9b457f8276 663 fastResponse=0; // reset and skip 200 ms wait
nixnax 36:2a9b457f8276 664 } else {
nixnax 38:ab582987926e 665 wait(0.2); // normally, you wait 200 ms before sending a TCP packet
nixnax 36:2a9b457f8276 666 }
nixnax 38:ab582987926e 667 sendFrame(); // All done! Send the TCP packet
nixnax 38:ab582987926e 668 ppp.seq = ppp.seq + dataLen; // increase OUR sequence by the outgoing data length - for the next round
nixnax 29:30de79d658f6 669 }
nixnax 26:11f4eb2663a7 670
nixnax 29:30de79d658f6 671 void dumpDataTCP()
nixnax 29:30de79d658f6 672 {
nixnax 26:11f4eb2663a7 673 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 674 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 35:e7068df4d971 675 int headerSizeTCP = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 35:e7068df4d971 676 int dataLen = ipPktLen - ipHeaderLen - headerSizeTCP; // data is what's left after the two headers
nixnax 29:30de79d658f6 677 if (v1) {
nixnax 42:4de44be70bfd 678 debug("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, headerSizeTCP, dataLen); // 1 for more verbose
nixnax 29:30de79d658f6 679 }
nixnax 29:30de79d658f6 680 if (dataLen > 0) {
nixnax 42:4de44be70bfd 681 debug("%s\n",ppp.pkt.buf+4+ipHeaderLen+headerSizeTCP); // show the data
nixnax 29:30de79d658f6 682 }
nixnax 29:30de79d658f6 683 }
nixnax 26:11f4eb2663a7 684
nixnax 29:30de79d658f6 685 void TCPpacket()
nixnax 29:30de79d658f6 686 {
nixnax 26:11f4eb2663a7 687 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 688 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 689 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 690 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 691 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 692 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 693 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 694 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 695 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 696 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 697 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 698 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 699 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 700
nixnax 29:30de79d658f6 701 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 702 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 703 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 704 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 705 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 706 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 707 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 708 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 709 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 710 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 29:30de79d658f6 711 char srcIP [16];
nixnax 29:30de79d658f6 712 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 713 char dstIP [16];
nixnax 29:30de79d658f6 714 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 715 if (v0) {
nixnax 42:4de44be70bfd 716 debug("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
nixnax 29:30de79d658f6 717 }
nixnax 29:30de79d658f6 718 if (v0) {
nixnax 42:4de44be70bfd 719 debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
nixnax 29:30de79d658f6 720 }
nixnax 28:1aa629be05e7 721 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 722 dumpDataTCP();
nixnax 26:11f4eb2663a7 723 tcpHandler();
nixnax 11:f58998c24f0b 724 }
nixnax 11:f58998c24f0b 725
nixnax 29:30de79d658f6 726 void otherProtocol()
nixnax 29:30de79d658f6 727 {
nixnax 29:30de79d658f6 728 debug(("Other IP protocol"));
nixnax 29:30de79d658f6 729 }
nixnax 26:11f4eb2663a7 730
nixnax 29:30de79d658f6 731 void IPframe()
nixnax 29:30de79d658f6 732 {
nixnax 10:74f8233f72c0 733 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 734 switch (protocol) {
nixnax 29:30de79d658f6 735 case 1:
nixnax 29:30de79d658f6 736 ICMPpacket();
nixnax 29:30de79d658f6 737 break;
nixnax 29:30de79d658f6 738 case 2:
nixnax 29:30de79d658f6 739 IGMPpacket();
nixnax 29:30de79d658f6 740 break;
nixnax 29:30de79d658f6 741 case 17:
nixnax 29:30de79d658f6 742 UDPpacket();
nixnax 29:30de79d658f6 743 break;
nixnax 29:30de79d658f6 744 case 6:
nixnax 29:30de79d658f6 745 TCPpacket();
nixnax 29:30de79d658f6 746 break;
nixnax 29:30de79d658f6 747 default:
nixnax 29:30de79d658f6 748 otherProtocol();
nixnax 29:30de79d658f6 749 }
nixnax 29:30de79d658f6 750 }
nixnax 9:0992486d4a30 751
nixnax 29:30de79d658f6 752 void LCPconfReq()
nixnax 29:30de79d658f6 753 {
nixnax 15:b0154c910143 754 debug(("LCP Config "));
nixnax 9:0992486d4a30 755 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 756 ppp.pkt.buf[4]=4; // allow only no options
nixnax 15:b0154c910143 757 debug(("Reject\n"));
nixnax 29:30de79d658f6 758 sendFrame();
nixnax 9:0992486d4a30 759 } else {
nixnax 9:0992486d4a30 760 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 15:b0154c910143 761 debug(("Ack\n"));
nixnax 9:0992486d4a30 762 sendFrame();
nixnax 15:b0154c910143 763 debug(("LCP Ask\n"));
nixnax 11:f58998c24f0b 764 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 765 sendFrame();
nixnax 9:0992486d4a30 766 }
nixnax 9:0992486d4a30 767 }
nixnax 9:0992486d4a30 768
nixnax 29:30de79d658f6 769 void LCPconfAck()
nixnax 29:30de79d658f6 770 {
nixnax 15:b0154c910143 771 debug(("LCP Ack\n"));
nixnax 29:30de79d658f6 772 }
nixnax 9:0992486d4a30 773
nixnax 29:30de79d658f6 774 void LCPend()
nixnax 29:30de79d658f6 775 {
nixnax 29:30de79d658f6 776 debug(("LCP End\n"));
nixnax 29:30de79d658f6 777 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 778 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 779 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 780 }
nixnax 9:0992486d4a30 781
nixnax 29:30de79d658f6 782 void LCPother()
nixnax 29:30de79d658f6 783 {
nixnax 29:30de79d658f6 784 debug(("LCP Other\n"));
nixnax 29:30de79d658f6 785 dumpFrame();
nixnax 29:30de79d658f6 786 }
nixnax 29:30de79d658f6 787
nixnax 29:30de79d658f6 788 void LCPframe()
nixnax 29:30de79d658f6 789 {
nixnax 29:30de79d658f6 790 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 791 switch (code) {
nixnax 29:30de79d658f6 792 case 1:
nixnax 29:30de79d658f6 793 LCPconfReq();
nixnax 29:30de79d658f6 794 break; // config request
nixnax 29:30de79d658f6 795 case 2:
nixnax 29:30de79d658f6 796 LCPconfAck();
nixnax 29:30de79d658f6 797 break; // config ack
nixnax 29:30de79d658f6 798 case 5:
nixnax 29:30de79d658f6 799 LCPend();
nixnax 29:30de79d658f6 800 break; // end connection
nixnax 29:30de79d658f6 801 default:
nixnax 29:30de79d658f6 802 LCPother();
nixnax 29:30de79d658f6 803 }
nixnax 9:0992486d4a30 804 }
nixnax 9:0992486d4a30 805
nixnax 29:30de79d658f6 806 void discardedFrame()
nixnax 29:30de79d658f6 807 {
nixnax 29:30de79d658f6 808 if (v0) {
nixnax 42:4de44be70bfd 809 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 810 }
nixnax 9:0992486d4a30 811 }
nixnax 9:0992486d4a30 812
nixnax 29:30de79d658f6 813 void determinePacketType()
nixnax 29:30de79d658f6 814 {
nixnax 29:30de79d658f6 815 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 29:30de79d658f6 816 debug(("byte0 != ff\n"));
nixnax 29:30de79d658f6 817 return;
nixnax 29:30de79d658f6 818 }
nixnax 29:30de79d658f6 819 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 29:30de79d658f6 820 debug(("byte1 != 3\n"));
nixnax 29:30de79d658f6 821 return;
nixnax 29:30de79d658f6 822 }
nixnax 29:30de79d658f6 823 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 29:30de79d658f6 824 debug(("byte2 != 21\n"));
nixnax 29:30de79d658f6 825 return;
nixnax 29:30de79d658f6 826 }
nixnax 9:0992486d4a30 827 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 828 switch (packetType) {
nixnax 29:30de79d658f6 829 case 0xc0:
nixnax 29:30de79d658f6 830 LCPframe();
nixnax 29:30de79d658f6 831 break; // link control
nixnax 29:30de79d658f6 832 case 0x80:
nixnax 29:30de79d658f6 833 IPCPframe();
nixnax 29:30de79d658f6 834 break; // IP control
nixnax 29:30de79d658f6 835 case 0x00:
nixnax 29:30de79d658f6 836 IPframe();
nixnax 29:30de79d658f6 837 break; // IP itself
nixnax 29:30de79d658f6 838 default:
nixnax 29:30de79d658f6 839 discardedFrame();
nixnax 9:0992486d4a30 840 }
nixnax 29:30de79d658f6 841 }
nixnax 9:0992486d4a30 842
nixnax 29:30de79d658f6 843 void scanForConnectString()
nixnax 29:30de79d658f6 844 {
nixnax 9:0992486d4a30 845 if ( ppp.online==0 ) {
nixnax 15:b0154c910143 846 char * clientFound = strstr( (char *)rxbuf, "CLIENTCLIENT" ); // look for PC string
nixnax 29:30de79d658f6 847 if( clientFound ) {
nixnax 9:0992486d4a30 848 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't get fixated
nixnax 9:0992486d4a30 849 pc.printf("CLIENTSERVER"); // respond to PC
nixnax 9:0992486d4a30 850 ppp.online=1; // we can stop looking for the string
nixnax 15:b0154c910143 851 debug(("Connect string found\n"));
nixnax 9:0992486d4a30 852 }
nixnax 9:0992486d4a30 853 }
nixnax 9:0992486d4a30 854 }
nixnax 9:0992486d4a30 855
nixnax 0:2cf4880c312a 856 int main()
nixnax 0:2cf4880c312a 857 {
nixnax 14:c65831c25aaa 858 pc.baud(115200); // USB virtual serial port
nixnax 41:e58a5a09f411 859 #ifndef SERIAL_PORT_MONITOR_NO
nixnax 15:b0154c910143 860 xx.baud(115200); // second serial port for debug(((((((( messages
nixnax 9:0992486d4a30 861 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 41:e58a5a09f411 862 #endif
nixnax 9:0992486d4a30 863 pppInitStruct(); // initialize all the PPP properties
nixnax 4:a469050d5b80 864
nixnax 9:0992486d4a30 865 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 4:a469050d5b80 866
nixnax 29:30de79d658f6 867 int frameStartIndex, frameEndIndex;
nixnax 29:30de79d658f6 868 int frameBusy=0;
nixnax 4:a469050d5b80 869
nixnax 0:2cf4880c312a 870 while(1) {
nixnax 9:0992486d4a30 871 if ( ppp.online==0 ) scanForConnectString(); // try to connect
nixnax 22:00df34cd4d7e 872 while ( rxbufNotEmpty() ) {
nixnax 1:9e03798d4367 873 int rx = pc_getBuf();
nixnax 29:30de79d658f6 874 if (frameBusy) {
nixnax 4:a469050d5b80 875 if (rx==FRAME_7E) {
nixnax 4:a469050d5b80 876 frameBusy=0; // done gathering frame
nixnax 4:a469050d5b80 877 frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 4:a469050d5b80 878 processFrame(frameStartIndex, frameEndIndex);
nixnax 4:a469050d5b80 879 }
nixnax 29:30de79d658f6 880 } else {
nixnax 4:a469050d5b80 881 if (rx==FRAME_7E) {
nixnax 4:a469050d5b80 882 frameBusy=1; // start gathering frame
nixnax 9:0992486d4a30 883 frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 4:a469050d5b80 884 }
nixnax 0:2cf4880c312a 885 }
nixnax 4:a469050d5b80 886 }
nixnax 7:ab147f5e97ac 887 }
nixnax 7:ab147f5e97ac 888 }