Diff: PPP-Blinky/ppp-blinky.h

Revision:

167:ff8a2d8beeb1

Parent:

165:c47826d07e0d

Child:

170:3d3b2126181c

--- a/PPP-Blinky/ppp-blinky.h	Sun Sep 03 19:20:11 2017 +0000
+++ b/PPP-Blinky/ppp-blinky.h	Mon Sep 04 04:13:15 2017 +0000
@@ -12,11 +12,24 @@
 
 /// PPP header
 typedef struct { // [ff 03 00 21]
-    unsigned int pppAddress : 8;  // always 0xff
-    unsigned int pppControl : 8;  // always 03
-    unsigned int pppProtocol : 16; // 2100 for IP (byte reversed, should be 0021)
+    unsigned int address : 8;  // always 0xff
+    unsigned int control : 8;  // always 03
+    unsigned int protocolR : 16; // byte reversed, 0x0021 for ip
 } pppHeaderType;
 
+/// LCP and IPCP header
+typedef struct {
+    // ppp part
+    unsigned int address : 8;  // always 0xff
+    unsigned int control : 8;  // always 03
+    unsigned int protocolR : 16; // byte reversed, 0x0021 for ip
+
+    // ipcp and lcp part
+    unsigned int code : 8; // IPCP and LCP contain a code field which identifies the requested action or response
+    unsigned int identifier : 8 ;
+    unsigned int lengthR : 16;
+} ipcpHeaderType;
+
 /// IP header
 typedef struct {
     unsigned int headerLength   :  4;  // ip headerlength / 4
@@ -25,26 +38,31 @@
     unsigned int ce             :  1;  // ecn-ce
     unsigned int dscp           :  6;  // differentiated services
     unsigned int lengthR        : 16;  // ip packet length (byte-reversed)
-    
+
     unsigned int identR         : 16;  // ident, byte reversed
     unsigned int fragmentOffsHi :  5;
     unsigned int lastFragment   :  1;
     unsigned int dontFragment   :  1;
     unsigned int reservedIP     :  1;
     unsigned int fragmentOffsLo :  8;
-    
+
     unsigned int ttl            :  8;
     unsigned int protocol       :  8;  // next protocol
     unsigned int checksumR      : 16;  // ip checksum, byte reversed
-    
-    unsigned int srcAdrR; // source IP address
-    unsigned int dstAdrR; // destination IP address
+    union {
+        unsigned int srcAdrR; // source IP address
+        char srcAdrPtr [0]; // so we also have a char * to srcAdrR
+    };
+    union {
+        unsigned int dstAdrR; // destination IP address
+        char dstAdrPtr [0];  // so we also have a char * to dstAdrR
+    };
 } ipHeaderType;
 
 /// IP pseudoheader. Used in TCP/UDP checksum calculations.
 typedef struct {
     union {
-        char start [0];
+        char start [0]; // a char * to avoid type conversions
         unsigned int srcAdrR; // source IP address
     };
     unsigned int dstAdrR; // destination IP address