Diff: PPP-Blinky/ppp-blinky.cpp

Revision:

160:bd701ad564cb

Parent:

159:4d1bf96a59cd

Child:

161:d59f778bc8ab

--- a/PPP-Blinky/ppp-blinky.cpp	Sat Sep 02 07:48:53 2017 +0000
+++ b/PPP-Blinky/ppp-blinky.cpp	Sat Sep 02 17:35:29 2017 +0000
@@ -166,7 +166,7 @@
     union {
         tcpHeaderType * tcp; // pointer to tcp header struct
         char * tcpStart; // char pointer to tcp header struct (need a char pointer for byte offset calculations)
-    };         
+    };
     int online; // we hunt for a PPP connection if this is zero
     int hostIP; // ip address of host
     int fcs; // PPP "frame check sequence" - a 16-bit HDLC-like checksum used in all PPP frames
@@ -703,14 +703,13 @@
     n=n+sprintf(pbuf+n, "%05d ",IPv4Id); // IPv4Id is a good way to correlate our dumps with net monitor or wireshark traces
 #define DUMP_FULL_IP_ADDRESS_YES
 #ifdef DUMP_FULL_IP_ADDRESS_YES
-    char * srcAdr =     (char *)&ppp.ip->srcAdrR; // 4 bytes
-    char * dstAdr =     (char *)&ppp.ip->dstAdrR; // 4 bytes = total of 20 bytes
-    //n=n+sprintf(pbuf+n, " %x %x ", ppp.pkt.ip.x, ppp.pkt.ip.y);
+    char * srcAdr = (char *)&ppp.ip->srcAdrR; 
+    char * dstAdr = (char *)&ppp.ip->dstAdrR; 
     n=n+sprintf(pbuf+n, " %d.%d.%d.%d %d.%d.%d.%d ",srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3], dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]); // full ip addresses
 #endif
     putsWhileCheckingInput( pbuf );
 #ifndef TCP_HEADER_DUMP_YES
-    putsWhileCheckingInput('\x1b[30m\n'); // there is no TCP header dump, so terminate the line with \n and VT100 code for black
+    putsWhileCheckingInput('\x1b[30m\n'); // if there's no TCP header dump we terminate the line with \n and VT100 code for black
 #endif
 #endif
 }
@@ -744,9 +743,11 @@
 #define EVERY_PACKET_ON_A_NEW_LINE_YES
 #ifdef EVERY_PACKET_ON_A_NEW_LINE_YES
     putsWhileCheckingInput("\x1b[30m\n"); // write a black color and newline after every packet
+#else
+    putsWhileCheckingInput("\x1b[30m"); // write a black color after every packet
 #endif
     if( outGoing && ppp.tcp->flag.fin ) { // ACK/FIN - if this is an outgoing FIN it's the end of a tcp conversation
-        putcWhileCheckingInput('\n'); // insert an extra new line to mark the end of an HTTP conversation
+        putcWhileCheckingInput('\n'); // insert an extra new line to mark the end (except for final ack) of an HTTP conversation
     }
 #endif
 }
@@ -778,8 +779,8 @@
     out[j]=0;
 }
 
-/// handle a request for an http websocket
-/// we end up here if we enter the following javascript in a web browser console: x = new WebSocket("ws://172.10.10.2");
+/// Handle a request for an http websocket.
+/// We end up here if we enter the following javascript in a web browser console: x = new WebSocket("ws://172.10.10.2");
 int webSocketHandler(char * dataStart)
 {
     int n=0; // byte counter
@@ -821,7 +822,7 @@
 {
     int n=0; // number of bytes we have printed so far
     n = webSocketHandler( dataStart ); // test for and handle WebSocket upgrade requests
-    if (n>0) return n; // if it's a WebSocket we already have the response, so return
+    if (n>0) return n; // if n>0 we already have a response, so return
 
     int nHeader; // byte size of HTTP header
     int contentLengthStart; // index where HTML starts
@@ -880,33 +881,27 @@
     return n; // total byte size of our response
 }
 
-/// handle TCP data that is not an HTTP get
-/// this is the response if we have TCP data but it's not an HTTP GET
-/// this is handy when you for example want to use netcat (nc.exe) to talk to PPP-Blinky
-/// this could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
+/// Handle TCP data that is not an HTTP GET.
+/// This is handy when for example you want to use netcat (nc.exe) to talk to PPP-Blinky.
+/// This could also be a websocket receive event - especially if the first byte is 0x81 (websocket data push)
 int tcpResponse(char * dataStart, int len, int * outFlags)
 {
     int n=0; // number of bytes we have printed so far
     if (dataStart[0] == 0x81) { // check if this is a websocket push message
-        // this is most likely a websocket push message. you get this when you enter this in your browser console: x.send("my message");
-        if (0) putsWhileCheckingInput( "Got data from websocket send()\n" );
-
-        // for now we simply echo the websocket data back to the client - the client should therefore see an onmessage event
-        // to display the echoed data in your browser, enter the following into the browser console: x.onmessage = function(msg){ console.log( msg.data ); }
-        if (1) {
-            char mask [4];
-            memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
-            int websocketMessageSize = len - 6;  // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
-            if((dataStart[1]&0x80)==0x80) // test if the mask bit is set, which means all data is xor'ed with the mask
-                for (int i=0; i<websocketMessageSize; i++) dataStart[i+6]^= mask[i%4]; // unmask each byte with one of the mask bytes
-            dataStart[1] = len-2; // add four extra bytes to the message length because we don't use mask bytes for the send
-            memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
-            n = len; // our response size remains exactly the same length as what we received
-        }
+        char mask [4];
+        memcpy ( mask, dataStart+2, 4); // websocket messages are "masked", so first we obtain the 4-byte mask
+        int websocketMessageSize = len - 6;  // 1 byte prefix (0x81), 1 byte, 4 bytes mask = 6 bytes
+        if((dataStart[1]&0x80)==0x80) // test if the mask bit is set, which means all data is xor'ed with the mask
+            for (int i=0; i<websocketMessageSize; i++) dataStart[i+6]^= mask[i%4]; // unmask each byte with one of the mask bytes
+        dataStart[1] = len-2; // add four extra bytes to the message length because we don't use mask bytes for the send
+        memcpy(dataStart+2, "Got:",4); // insert our own text into the four mask bytes
+        n = len; // our response size remains exactly the same length as what we received
     } else if ( (dataStart[0]==0x88) && (dataStart[1]==0x80) && (len == 6) ) { // test for a websocket close request
         n=2; // our close command is only two bytes long because we don't use the four mask bytes
         dataStart[1]=0; // we don't have mask bytes on
-    } else if (v1) putsWhileCheckingInput("TCP data received\n");
+    } else {
+        if (v1) putsWhileCheckingInput("TCP data received\n"); // all other tcp push packets
+    }        
     return n; // total byte size of our response
 }
 
@@ -915,17 +910,14 @@
 void tcpHandler()
 {
     // IP header
-    char * ipPkt = ppp.pkt.buf+4; // ip packet start
-    char * protocol =   ipPkt+9;  // 1 byte
-    char protocolIP = protocol[0];
     int packetLengthIp = __REV16(ppp.ip->lengthR ); // size of ip packet
     int headerSizeIp = 4 * ppp.ip->headerLength;  // size of ip header
 
     // TCP header
-    
+
     ppp.tcpStart = ppp.ipStart + headerSizeIp; // calculate where the TCP header starts
     int tcpSize = packetLengthIp - headerSizeIp; // tcp size = size of ip payload
-    char * tcp           = ppp.ipStart+headerSizeIp; // start of tcp packet
+    char * tcp = ppp.ipStart+headerSizeIp; // calculate start of tcp packet
 
     int headerSizeTcp = 4 * (ppp.tcp->offset); // tcp "offset" for start of data is also the header size
 
@@ -950,7 +942,7 @@
     int dataLen = 0; // most of our responses will have zero TCP data, only a header
     int flagsOut = TCP_FLAG_ACK; // the default case is an ACK packet
     //int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1]; // the tcp flags we received
-    
+
     ppp.tcp->windowR = __REV16( 700 ); // set tcp window size to 700 bytes
 
     // A sparse TCP flag interpreter that implements stateless TCP connections
@@ -988,7 +980,7 @@
 
     ppp.tcp->ackTcpR = __REV( ack_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
     ppp.tcp->seqTcpR = __REV( seq_out ); // byte reversed - tcp/ip messages are big-endian (high byte first)
-    
+
     ppp.tcp->flag.All = flagsOut; // update the TCP flags
 
     // recalculate all the header sizes
@@ -1006,13 +998,13 @@
     pseudoHeader.srcAdrR = ppp.ip->srcAdrR; // copy in ip source address
     pseudoHeader.dstAdrR = ppp.ip->dstAdrR; // copy in ip dest address
     pseudoHeader.zero = 0; // padding
-    pseudoHeader.protocol = protocolIP; // protocol number
+    pseudoHeader.protocol = ppp.ip->protocol; // protocol number
     pseudoHeader.lengthR = __REV16( tcpSize ); // size of tcp packet
     dataCheckSum(pseudoHeader.start, 12, 1); // start with the TCP checksum of the pseudoheader
     ppp.tcp->checksumR = 0; // before TCP checksum calculations the checksum bytes must be set cleared
     unsigned int pseudoHeaderSum=dataCheckSum((unsigned char *)ppp.tcpStart,tcpSize, 0); // continue the TCP checksum on the whole TCP packet
     ppp.tcp->checksumR = __REV16( pseudoHeaderSum); // tcp checksum done, store it in the TCP header
-   
+
     dumpHeaderIP(1); // dump outgoing IP header
     dumpHeaderTCP(1); // dump outgoing TCP header
     for (int i=0; i<45*1000/10; i++) { // 45 ms delay before sending frame - a typical internet delay time