More work on encoding and decoding various gnunet messages.

3 files changed, 66 insertions, 23 deletions

diff --git a/src/org/gnu/clojure/gnunet/hello.clj b/src/org/gnu/clojure/gnunet/hello.clj
index b024f63..d63edef 100644
--- a/src/org/gnu/clojure/gnunet/hello.clj
+++ b/src/org/gnu/clojure/gnunet/hello.clj
@@ -12,12 +12,16 @@
     (encode-int64 (.getTime (:expiration transport)))
     (:encoded-address transport)))
 
+(defn decode-transports-and-split
+  [a]
+  )
+
 (defn encode-hello
   "Encode a hello message."
-  [public-key transports]
+  [hello]
   (let [padding (encode-int32 0)
-        encoded-key (encode-rsa-public-key public-key)
-        encoded-transports (mapcat encode-transport transports)
+        encoded-key (encode-rsa-public-key (:public-key hello))
+        encoded-transports (mapcat encode-transport (:transports hello))
         size (+ header-size
                (count padding)
                (count encoded-key)
@@ -27,3 +31,15 @@
       padding
       encoded-key
       encoded-transports)))
+
+(defn decode-hello-and-split
+  [a]
+  (let [[header after-header] (decode-header-and-split a)
+        [padding after-padding] (split-at 4 after-header)
+        [public-key after-public-key] (decode-rsa-public-key-and-split
+                                        after-padding)
+        [transports after-transports] (decode-transports-and-split
+                                        after-public-key)]
+    [{:public-key public-key
+      :transports transports}
+     after-transports]))
diff --git a/src/org/gnu/clojure/gnunet/identity.clj b/src/org/gnu/clojure/gnunet/identity.clj
index f6cecfd..ec729ee 100644
--- a/src/org/gnu/clojure/gnunet/identity.clj
+++ b/src/org/gnu/clojure/gnunet/identity.clj
@@ -1,21 +1,12 @@
 (ns org.gnu.clojure.gnunet.identity
   (:use (org.gnu.clojure.gnunet crypto message)))
 
-(defn bit-count-to-bytes [x] (quot (+ 7 x) 8))
-
-(defn encode-bigint
-  "Convert a bigInteger to a sequence of bytes in network order."
-  [x]
-  (let [len (bit-count-to-bytes (.bitLength x))
-        a (.toByteArray x)]
-    (drop (- (alength a) len) a)))
-
 (defn encode-rsa-public-key
   "Convert an RSA public key to a sequence of bytes in gnunet format."
-  [key]
-  (let [modulus (encode-bigint (.getModulus key)) 
+  [public-key]
+  (let [modulus (encode-int (.getModulus public-key)) 
         modulus-len (count modulus)
-        exponent (encode-bigint (.getPublicExponent key))
+        exponent (encode-int (.getPublicExponent public-key))
         exponent-len (count exponent)]
     (concat
       (encode-int16 (+ modulus-len exponent-len 4))
@@ -24,6 +15,10 @@
       exponent
       (encode-int16 0))))
 
+(defn decode-rsa-public-key-and-split
+  [a]
+  )
+
 (defn generate-id
   "Generate the SHA-512 digest of the encoded public key."
   [keypair]
diff --git a/src/org/gnu/clojure/gnunet/message.clj b/src/org/gnu/clojure/gnunet/message.clj
index 9d0b74d..3701260 100644
--- a/src/org/gnu/clojure/gnunet/message.clj
+++ b/src/org/gnu/clojure/gnunet/message.clj
@@ -1,25 +1,57 @@
-(ns org.gnu.clojure.gnunet.message)
+(ns org.gnu.clojure.gnunet.message
+  (:import java.math.BigInteger))
+
+(defn bit-count-to-bytes [x] (quot (+ 7 x) 8))
+
+(defn encode-int
+  "Convert an integer to a sequence of bytes in network order."
+  [x]
+  (let [big (bigint x)
+        len (max 1 (bit-count-to-bytes (.bitLength big)))
+        a (.toByteArray big)]
+    (drop (- (alength a) len) a)))
 
 (defn encode-int16
   "Convert a 16-bit integer to a sequence of bytes in network order."
   [x]
-  (list (byte (quot x 256)) (byte (rem x 256))))
+  (list (byte (bit-shift-right x 8)) (byte (bit-and x 0xFF))))
 
 (defn encode-int32
   "Convert a 32-bit integer to a sequence of bytes in network order."
   [x]
-  (concat (encode-int16 (quot x 65536)) (encode-int16 (rem x 65536))))
+  (concat (encode-int16 (bit-shift-right x 16))
+    (encode-int16 (bit-and x 0xFFFF))))
 
 (defn encode-int64
   "Convert a 64-bit integer to a sequence of bytes in network order."
   [x]
-  (concat (encode-int32 (quot x 4294967269)) (encode-int32 (rem x 4294967269))))
+  (concat (encode-int32 (bit-shift-right (bigint x) 32))
+    (encode-int32 (bit-and x 0xFFFFFFFF))))
+
+(defn decode-int
+  "Convert a sequence of bytes in network order to a 2's complement integer"
+  [a]
+  (BigInteger. (byte-array a)))
+
+(defn decode-uint
+  "Convert a sequence of bytes in network order to an unsigned integer"
+  [a]
+  (BigInteger. 1 (byte-array a)))
 
 (defn encode-header
   "Encode a gnunet message header."
-  [size message-type]
+  [hdr]
   (concat
-    (encode-int16 size)
-    (encode-int16 message-type)))
+    (encode-int16 (:size hdr))
+    (encode-int16 (:message-type hdr))))
+
+(def header-size (count (encode-header {:size 0 :message-type 0})))
 
-(def header-size (count (encode-header 0 0)))
\ No newline at end of file
+(defn decode-header-and-split
+  "Split a seq into a gnunet message header and the rest"
+  [a]
+  (let [[encoded-size after-encoded-size] (split-at 2 a)
+        [encoded-type after-encoded-type] (split-at 2 after-encoded-size)]
+    [{:size (decode-uint encoded-size)
+      :message-type (decode-uint encoded-type)}
+     after-encoded-type]))