Further defined the next protocol version

Author: cjdelisle

doc/FutureHeaders.h

@@ -19,24 +19,29 @@
 
 #include <inttypes.h>
 
-struct InterRouter
-{
-    // What goes here?
-};
-
 /**
  * The RouteHeader is hidden from the switches by the l2 encryption layer but it is seen
  * by every router which hands off the packet.
+ *
+ *                     1               2               3
+ *     0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  0 | ver |           MTU           |            Flow ID            |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  4 |                                                               |
+ *    +                                                               +
+ *  8 |                                                               |
+ *    +                        Destination IP6                        +
+ * 12 |                                                               |
+ *    +                                                               +
+ * 16 |                                                               |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Ver is 3 bits representing the protocol version *modulo 8*, 
  */
 struct RouteHeader
 {
-    /**
-     * This is to be initialized to what the sending node believes is the full path MTU
-     * (or 0xffff if unsure) and clamped to the MTU of each path by the routers which forward
-     * the packet.
-     * Little endian.
-     */
-    uint16_t mtu_le;
+    uint16_t versionAndMtu_be;
 
     /**
      * An arbitrary value created by hashing information which represents the dataflow such
@@ -59,6 +64,28 @@ struct RouteHeader
 #define RouteHeader_SIZE 20
 Assert_compileTime(sizeof(struct RouteHeader) == RouteHeader_SIZE);
 
+
+static inline void RouteHeader_setVersion(struct RouteHeader* hdr, uint8_t version)
+{
+    type->versionAndMtu_be = (type->versionAndMtu_be & Endian_hostToBigEndian16(0x1fff)) |
+        Endian_hostToBigEndian16((version % 8) << 13);
+}
+
+static inline uint8_t RouteHeader_getVersion(struct RouteHeader* hdr)
+{
+    return Endian_bigEndianToHost16(type->versionAndMtu_be) >> 13;
+}
+
+static inline uint16_t RouteHeader_getMTU(struct RouteHeader* hdr)
+{
+    return Endian_bigEndianToHost16(type->versionAndMtu_be) >> 13;
+}
+
+     * This is to be initialized to what the sending node believes is the full path MTU
+     * (or 0xffff if unsure) and clamped to the MTU of each path by the routers which forward
+     * the packet.
+
+
 #endif
 
 
@@ -86,6 +113,12 @@ Assert_compileTime(sizeof(struct RouteHeader) == RouteHeader_SIZE);
 #include "util/Endian.h"
 
 /**
+ *                     1               2               3
+ *     0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  0 | ver |R| unused|    unused     |         Content Type          |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
  * The DataHeader is protected from the switches by the l2 encryption layer and from the
  * routers by the l3 layer of encryption. It's primary uses are to tell the endpoint enough
  * information to route the packet to the correct cjdns subsystem and (maybe) reconstruct
@@ -98,11 +131,17 @@ struct DataHeader
      * milliseconds it has something else to send back, this is acceptable, otherwise it should
      * synthisize a control packet to respond with.
      */
-    #define DataHeader_highBits_RESPOND_TO_ME   Endian_hostToLittleEndian16(1<<15)
+    #define DataHeader_RESPOND_TO_ME (1<<7)
+
+    /**
+     * Version is set to the version of the data as per Version.h
+     * If the number is over 255, it wraps
+     */
+    uint8_t versionAndFlags;
 
-    uint16_t highBits_le;
+    uint8_t unused;
 
-    // TODO What goes here?
+    uint16_t contentType_be;
 };
 #define DataHeader_SIZE 4
 Assert_compileTime(sizeof(struct DataHeader) == DataHeader_SIZE);
@@ -149,30 +188,41 @@ enum DataHeader_ContentType
      * cjdns on other machines, providing they first agree on which numbers to use via
      * CTRL messages.
      */
-    DataHeader_ContentType_AVAILABLE =     257,
-    DataHeader_ContentType_AVAILABLE_MAX = 32767
+    DataHeader_ContentType_AVAILABLE =     257),
+    DataHeader_ContentType_AVAILABLE_MAX = 0xffff
 };
 
 static inline enum DataHeader_ContentType DataHeader_getContentType(struct DataHeader* hdr)
 {
-    return Endian_littleEndianToHost16( hdr->highBits_le & ~DataHeader_highBits_RESPOND_TO_ME );
+    return Endian_bigEndianToHost16(hdr->contentType_be);
 }
 
 static inline void DataHeader_setContentType(struct DataHeader* hdr,
                                              enum DataHeader_ContentType type)
 {
     Assert_true(type <= DataHeader_ContentType_AVAILABLE_MAX);
-    hdr->highBits_le = (hdr->highBits_le & DataHeader_highBits_RESPOND_TO_ME) |
-        Endian_hostToLittleEndian16(type);
+    hdr->contentType_be = Endian_hostToBigEndian16(type);
 }
 
 static inline void DataHeader_setRespondToMe(struct DataHeader* hdr, bool rtm)
 {
-    type->highBits_le = (type->highBits_le & ~DataHeader_highBits_RESPOND_TO_ME) |
-        (rtm) ? DataHeader_highBits_RESPOND_TO_ME : 0;
+    type->versionAndFlags = (type->versionAndFlags & ~DataHeader_RESPOND_TO_ME) |
+        (rtm) ? DataHeader_RESPOND_TO_ME : 0;
 }
 
 static inline bool DataHeader_getRespondToMe(struct DataHeader* hdr)
 {
-    return type->highBits_le & DataHeader_highBits_RESPOND_TO_ME;
+    return type->versionAndFlags & DataHeader_RESPOND_TO_ME;
 }
+
+static inline void DataHeader_setVersion(struct DataHeader* hdr, uint8_t version)
+{
+    type->versionAndFlags = (type->versionAndFlags & 0x1f) | ((version % 8) << 5);
+}
+
+static inline uint8_t DataHeader_getVersion(struct DataHeader* hdr)
+{
+    return type->versionAndFlags >> 5;
+}
+
+#endif

doc/djc_layer_model.md

@@ -26,8 +26,8 @@ Direct over phy (future):
 
 ## LayerB
 Switch Layer, this layer is seen by all switches along a direct path as well as the routers
-at the ends of the path but no information in this layer is directly passed to routers
-downstream in the forwarding path.
+at the ends of the path but when a router forwards the packet on, headers at this layer are
+replaced with new ones just as the Ethernet header is replaced by each IP router.
 
 This layer contains:
 
@@ -40,12 +40,10 @@ No data in this layer is directly forwarded on to the final endpoints or downstr
 and no data at this layer or below it can be accessed by the switches due to a CryptoAuth header
 which begins this layer. Since the width of a CryptoSessionHeader depends on the state of the
 CryptoAuth session represented, a router should only forward packets to another router after
-the CryptoAuth session with that router has entered into the ESTABLISHED state in to prevent
+the CryptoAuth session with that router has entered into the ESTABLISHED state in order to prevent
 fluctuating MTU.
 
-    [ CryptoSessionHeader ][ InterRouter ]
-
-NOTE: In versions previous to v9, InterRouter was omitted.
+    [ CryptoSessionHeader ]
 
 ### LayerC Control Packet
 In order for switches to send error and other control messages, a branch of *LayerC* exists which
@@ -70,7 +68,7 @@ NOTE: In versions previous to v9, RouteHeader is replaced with an IPv6 header.
 
 ## LayerE
 Data layer, this layer is only of interest to the sender and the recipient. It it protected by
-a CryptoAuth header which prevents intermediate routers from accessing the data therein.
+a CryptoAuth layer which prevents intermediate routers from accessing the data therein.
 
 This layer contains:
 
@@ -108,9 +106,8 @@ CryptoAuth session state.
     [ CryptoAuth ]            20
     [ SwitchHeader ]          12
     [ CryptoSessionHeader ]   24
-    [ InterRouter ]            4?
     [ RouteHeader ]           20
     [ CryptoSessionHeader ]   24/124
-    [ DataHeader ]             4?
+    [ DataHeader ]             4
     [ TCP/UDP/other ]
     [ user's data ]