Diff: main.cpp

Revision:

114:8a5d70bbc1b2

Parent:

113:d9666fe4d0ed

Child:

115:b8ddff0e782f

--- a/main.cpp	Sat Aug 05 08:45:32 2017 +0000
+++ b/main.cpp	Sun Aug 06 10:29:41 2017 +0000
@@ -7,7 +7,7 @@
 
 // Notes and Instructions
 // http://bit.ly/PPP-Blinky-Instructions
-// http://bit.ly/win-rasdial-config 
+// http://bit.ly/win-rasdial-config
 
 // Handy reading material
 // https://technet.microsoft.com/en-us/library/cc957992.aspx
@@ -37,31 +37,31 @@
 // The #define below enables/disables a second (OPTIONAL) serial port that prints out interesting diagnostic messages.
 // Change to SERIAL_PORT_MONITOR_YES to enable diagnostics messages. You need to wire a second serial port to your mbed hardware to monitor this.
 // Note - the LPC11U24 does NOT have a second serial port
-#define SERIAL_PORT_MONITOR_YES /* change to SERIAL_PORT_MONITOR_YES for debug messages */
+#define SERIAL_PORT_MONITOR_NO /* change to SERIAL_PORT_MONITOR_YES for debug messages */
 
 // here we define the OPTIONAL, second debug serial port for the various target boards
 // insert your target board's port here if it's not in yet - if it works, please send it to me - thanks!!!
-#if !defined(SERIAL_PORT_MONITOR_NO) 
-#if defined(TARGET_LPC1768)
-Serial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
-#elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
-Serial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
-#elif defined(TARGET_LPC11U24)
-#error The LPC11U24 does not have a second serial port to use for debugging - change SERIAL_PORT_MONITOR_YES back to SERIAL_PORT_MONITOR_NO
+#ifdef SERIAL_PORT_MONITOR_YES
+    #if defined(TARGET_LPC1768)
+        Serial xx(p9, p10); // Second serial port on LPC1768 - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
+    #elif defined(TARGET_NUCLEO_F446RE) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_L053R8) || defined(TARGET_NUCLEO_L476RG) || defined(TARGET_NUCLEO_F401RE)
+        Serial xx(PC_10, PC_11); // Second serial port on NUCLEO boards - not required to run, if you get compile error here, change #define SERIAL_PORT_MONITOR_YES to #define SERIAL_PORT_MONITOR_NO
+    #elif defined(TARGET_LPC11U24)
+        #error The LPC11U24 does not have a second serial port to use for debugging - change SERIAL_PORT_MONITOR_YES back to SERIAL_PORT_MONITOR_NO
+    #else
+        #error Add your target board's second serial port here if you want to use debugging - or choose SERIAL_PORT_MONITOR_NO
+    #endif
+    #define debug(x...) xx.printf (x) /* if we have a serial port we print debug messages */
 #else
-#error Add your target board's second serial port here if you want to use debugging - or choose SERIAL_PORT_MONITOR_NO
-#endif
-
-#define debug(x...) xx.printf (x) /* if we have a serial port we print debug messages */
-
-#else
-#define debug(x...) {} /* if we don't have a serial port we do nothing */
+    #define debug(x...) {} /* if we don't have a serial port we do nothing */
 #endif
 
 // verbosity flags used in debug printouts - change to 1 to see increasingly more detailed debug info.
 #define v0 1
 #define v1 0
 #define v2 0
+#define IP_HEADER_DUMP_YES /* YES for ip header dump */
+#define TCP_HEADER_DUMP_YES /* YES for tcp header dump */
 
 // this is the webpage we serve when we get an HTTP request to root (/)
 // keep size under ~900 bytes to fit into a single PPP packet
@@ -98,7 +98,6 @@
 // a structure to keep all our ppp globals in
 struct pppType {
     int online; // we hunt for a PPP connection if this is zero
-    unsigned int ident; // our IP ident value
     int crc; // for calculating IP and TCP CRCs
     int ledState; // state of LED1
     int httpPageCount;
@@ -121,6 +120,9 @@
         int frameStartIndex; // frame start marker
         int frameEndIndex; // frame end marker
     } hdlc; // hdlc frame objects
+    struct {
+        unsigned int ident; // our IP ident value (outgoing frame count)
+    } ip; // ip related object
 };
 
 pppType ppp; // our global - definitely not thread safe
@@ -135,7 +137,7 @@
     ppp.rx.head=0;
     ppp.rx.buflevel=0;
     ppp.pkt.len=0;
-    ppp.ident=1000;
+    ppp.ip.ident=10000; // easy to recognize in ip packet dumps
     ppp.ledState=0;
     ppp.hdlc.frameStartIndex=0;
     ppp.httpPageCount=0;
@@ -183,8 +185,8 @@
             if (ch == 0x7E) {
                 ppp.online = 1;
                 debug("HDLC Frame (0x7E)\n");
-            }                
-        }            
+            }
+        }
         ppp.rx.head = hd; // update head pointer
         ppp.rx.buflevel++;
     }
@@ -365,7 +367,6 @@
 
 unsigned int dataCheckSum(unsigned char * ptr, int len)
 {
-
     unsigned int sum=0;
     unsigned char placeHolder;
     if (len&1) {
@@ -472,85 +473,78 @@
 
 void IGMPpacket()   // internet group management protocol
 {
-    if (v0) {
-        debug("IGMP type=%d \n", ppp.pkt.buf[28]);
-    }
+    if (v0) debug("IGMP type=%d \n", ppp.pkt.buf[28]);
 }
 
-void dumpHeaderIP ()
+void dumpHeaderIP (int outGoing)
 {
-    if (v0) {
-        char * ipPkt = ppp.pkt.buf+4; // ip packet start
-#ifndef SERIAL_PORT_MONITOR_NO
-        char * version =    ipPkt; // top 4 bits
-        char * ihl =        ipPkt; // bottom 4 bits
-        char * dscp =       ipPkt+1; // top 6 bits
-        char * ecn =        ipPkt+1; // lower 2 bits
-        char * pktLen =     ipPkt+2; // 2 bytes
-        char * ident =      ipPkt+4; // 2 bytes
-        char * flags =      ipPkt+6; // 2 bits
-        char * ttl =        ipPkt+8; // 1 byte
-        char * protocol =   ipPkt+9; // 1 byte
-        char * headercheck= ipPkt+10; // 2 bytes
+#if defined(IP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
+    char * ipPkt = ppp.pkt.buf+4; // ip packet start
+    char * ident =      ipPkt+4;  // 2 bytes
+    char * srcAdr =     ipPkt+12; // 4 bytes
+    char * dstAdr =     ipPkt+16; // 4 bytes = total of 20 bytes
+#ifdef UNUSED_IP_VARIABLES
+    char * version =    ipPkt;    // top 4 bits
+    char * ihl =        ipPkt;    // bottom 4 bits
+    char * dscp =       ipPkt+1;  // top 6 bits
+    char * ecn =        ipPkt+1;  // lower 2 bits
+    char * pktLen =     ipPkt+2;  // 2 bytes
+    char * flags =      ipPkt+6;  // 2 bits
+    char * ttl =        ipPkt+8;  // 1 byte
+    char * protocol =   ipPkt+9;  // 1 byte
+    char * headercheck= ipPkt+10; // 2 bytes
+    int versionIP = (version[0]>>4)&0xf;
+    int headerSizeIP = (ihl[0]&0xf)*4;
+    int dscpIP = (dscp[0]>>2)&0x3f;
+    int ecnIP = ecn[0]&3;
+    int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
+    int flagsIP = flags[0]>>14&3;
+    int ttlIP = ttl[0];
+    int protocolIP = protocol[0];
+    unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
 #endif
-        char * srcAdr =     ipPkt+12; // 4 bytes
-        char * dstAdr =     ipPkt+16; // 4 bytes = total of 20 bytes
-
-#ifndef SERIAL_PORT_MONITOR_NO
-        int versionIP = (version[0]>>4)&0xf;
-        int headerSizeIP = (ihl[0]&0xf)*4;
-        int dscpIP = (dscp[0]>>2)&0x3f;
-        int ecnIP = ecn[0]&3;
-        int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
-        int identIP = (ident[0]<<8)|ident[1];
-        int flagsIP = flags[0]>>14&3;
-        int ttlIP = ttl[0];
-        int protocolIP = protocol[0];
-        unsigned int checksumIP = (headercheck[0]<<8)|headercheck[1];
+    int identIP = (ident[0]<<8)|ident[1];
+#ifndef DUMP_FULL_IP_ADDRESS
+    xx.printf("IP %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
+#else
+    xx.printf("IP %d %d ",srcAdr[3], dstAdr[3]); // short format - only least significant byte of the ip addresses
 #endif
-
-        char srcIP [16];
-        snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
-        char dstIP [16];
-        snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
-        debug("IP %s %s v%d h%d d%d e%d L%03d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength);
-        debug("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP);
-        while ( pc.readable() ) fillbuf();
-    }
+    xx.printf("Ident %05d ",identIP); // ident is a good way to correlate our dumps with net monitor or wireshark traces
+#ifndef TCP_HEADER_DUMP_YES
+    xx.putc('\n'); // there is no TCP header dump, so terminate the line with \n
+#endif
+#endif
 }
 
-void dumpHeaderTCP()
+void dumpHeaderTCP(int outGoing)
 {
-    if( v0 ) {
-        int headerSizeIP     = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
-        char * tcpStart      =  ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
-#ifndef SERIAL_PORT_MONITOR_NO
-        char * seqtcp        = tcpStart + 4;  // 4 bytes
-        char * acktcp        = tcpStart + 8;  // 4 bytes
-#endif
-        char * flagbitstcp   = tcpStart + 12; // 9 bits
-#ifndef SERIAL_PORT_MONITOR_NO
-        unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
-        unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
-#endif
-        int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
+#if defined(TCP_HEADER_DUMP_YES) && defined(SERIAL_PORT_MONITOR_YES)
+    int headerSizeIP     = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
+    char * tcpStart      =  ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
+    char * seqtcp        = tcpStart + 4;  // 4 bytes
+    char * acktcp        = tcpStart + 8;  // 4 bytes
+    char * flagbitstcp   = tcpStart + 12; // 9 bits
+    unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
+    unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
+    if (seq && ack) {} // shut up the compiler about unused variables
+    int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
 
-        char flagInfo[10]; // text string presentating the TCP flags
-        memset(flagInfo,'.', 9); // fill string with "........."
-        memset(flagInfo+9,0,1); // null terminate string
+    char flagInfo[9]; // text string presentating the 8 most important TCP flags
+    memset(flagInfo,'.', 8); // fill string with "........"
+    flagInfo[8]=0; // null terminate string
 
-        if (flags & (1<<0)) flagInfo[8]='F';
-        if (flags & (1<<1)) flagInfo[7]='S';
-        if (flags & (1<<2)) flagInfo[6]='R';
-        if (flags & (1<<3)) flagInfo[5]='P';
-        if (flags & (1<<4)) flagInfo[4]='A';
-        if (flags & (1<<5)) flagInfo[3]='U';
-        if (flags & (1<<6)) flagInfo[2]='E';
-        if (flags & (1<<7)) flagInfo[1]='C';
-        if (flags & (1<<8)) flagInfo[0]='N';
-        debug("TCP Flags %s Seq %u Ack %u\n", flagInfo, seq, ack); // show the flags in debug
-        while ( pc.readable() ) fillbuf();
-    }
+    if (flags & (1<<0)) flagInfo[7]='F';
+    if (flags & (1<<1)) flagInfo[6]='S';
+    if (flags & (1<<2)) flagInfo[5]='R';
+    if (flags & (1<<3)) flagInfo[4]='P';
+    if (flags & (1<<4)) flagInfo[3]='A';
+    if (flags & (1<<5)) flagInfo[2]='U';
+    if (flags & (1<<6)) flagInfo[1]='E';
+    if (flags & (1<<7)) flagInfo[0]='C';
+    xx.printf("%s Seq %10u\n", flagInfo, seq); // tcp flags and the sequence number
+    if( (flags == (1<<4)) && outGoing ) // if this is a pure ack its probably then of the TCP link
+        xx.putc('\n'); // so insert an extra line to mark the end of the conversation
+#endif
 }
 
 int httpResponse(char * dataStart)
@@ -566,7 +560,7 @@
     xFetch = strncmp(dataStart, "GET /x", 6); // found GET /x , respond to both HTTP/1.<anything>
     // for example, in linux, xFetch can be used as:   echo GET /x | nc 172.10.10.2
     if( (httpGetRoot==0) || (xFetch==0) ) {
-        n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: mbed-PPP-Blinky\r\n"); // 200 OK header
+        n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK \r\nServer: mbed-PPP-Blinky \r\n"); // 200 OK header
     } else {
         n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\nServer: mbed-PPP-Blinky\r\n"); // 404 header
     }
@@ -695,14 +689,12 @@
     windowsizetcp[0]=2; // tcp window size = 700
     windowsizetcp[1]=0xbc; // tcp windows size = 700
 
-    int doFin = 0; // flag to see if we have to send an extra FIN message to shut down the link
-
     // A sparse TCP flag interpreter that implements stateless TCP connections
 
     switch ( flagsTCP ) {
         case TCP_FLAG_SYN:
             flagsOut = TCP_FLAG_SYN | TCP_FLAG_ACK; // something wants to connect - acknowledge it
-            seq_out = seq_in+0x1000U; // create a new sequence number using their sequence as a base
+            seq_out = seq_in+0x10000000U; // create a new sequence number using their sequence as a base
             ack_out++; // for SYN flag we have to increase the sequence by 1
             break;
         case TCP_FLAG_ACK | TCP_FLAG_PSH:
@@ -715,7 +707,6 @@
             break;
         case TCP_FLAG_FIN | TCP_FLAG_PSH | TCP_FLAG_ACK:
         case TCP_FLAG_FIN | TCP_FLAG_ACK:
-        case TCP_FLAG_RST:
             ack_out++; // for FIN flag we always have to increase sequence by 1
             break;
         case TCP_FLAG_FIN:
@@ -737,8 +728,6 @@
     memcpy(srctcp, dsttcp,2);
     memcpy(dsttcp, tempHold,2); // swap ip port source/dest
 
-sendTCP:
-
     acktcp[0]=ack_out>>24;
     acktcp[1]=ack_out>>16;
     acktcp[2]=ack_out>>8;
@@ -751,10 +740,10 @@
 
     flagbitstcp[1] = flagsOut; // update the TCP flags
 
-    // increment the ip ident number
-    ppp.ident++; // get next ident number for our packet
-    ident[0] = ppp.ident>>8;
-    ident[1] = ppp.ident>>0; // insert OUR ident
+    // increment our outgoing ip packet counter
+    ppp.ip.ident++; // get next ident number for our packet
+    ident[0] = ppp.ip.ident>>8;
+    ident[1] = ppp.ip.ident>>0; // insert OUR ident
 
     // Now we recalculate all the header sizes
     int newPacketSize = headerSizeIP + headerSizeTCP + dataLen; // calculate size of the outgoing packet
@@ -786,17 +775,10 @@
     checksumtcp[0]=pseudoHeaderSum>>8;
     checksumtcp[1]=pseudoHeaderSum;
     memcpy( tcp-12, tempHold, 12); // restore the 12 bytes that the pseudo-header overwrote
-
-//    dumpHeaderIP();
-//    dumpHeaderTCP();
-
+    dumpHeaderIP(1); // dump outgoing IP header
+    dumpHeaderTCP(1); // dump outgoing TCP header
+    wait_ms(8); // wait long enoug to get 90 characters printed at 115200 bps
     send_pppFrame(); // All preparation complete - send the TCP response
-
-    if (doFin==1) { // they want to shut down the link, so we have to send another packet to close our side of the link
-        doFin=0;
-        flagsOut = TCP_FLAG_ACK | TCP_FLAG_FIN; // tell them we are also finished
-        goto sendTCP; // send our final packet for this conversation.
-    }
 }
 
 void dumpDataTCP()
@@ -816,8 +798,8 @@
 
 void TCPpacket()
 {
-    dumpHeaderIP();
-    dumpHeaderTCP();
+    dumpHeaderIP(0);     // dump incoming packet header
+    dumpHeaderTCP(0);   // dump incoming packet header
     if (v2) {
         dumpDataTCP();
     }
@@ -951,9 +933,9 @@
             int rx = pc_getBuf(); // get the character
             if (rx==FRAME_7E) {
                 ppp.hdlc.frameEndIndex=oldTail; // mark the frame end character
-                
+
                 processHDLCFrame(ppp.hdlc.frameStartIndex, ppp.hdlc.frameEndIndex); // process the frame
-                
+
                 ppp.rx.rtail = ppp.rx.tail;
                 ppp.hdlc.frameStartIndex = ppp.rx.tail; // where next frame will start
                 break;
@@ -965,7 +947,7 @@
 void scanForConnectString()
 {
     while(ppp.online == 0) {
-        fillbuf();
+        fillbuf(); // gather received characters
         // search for Windows Dialup Networking "Direct Connection Between Two Computers" expected connect string
         char * found1 = strstr( (char *)ppp.rx.buf, "CLIENT" );
         if (found1 != NULL) {
@@ -984,6 +966,22 @@
 
 
 
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
 int main()
 {
     pc.baud(115200); // USB virtual serial port