Some more work on hello messages.

4 files changed, 76 insertions, 26 deletions

diff --git a/src/org/gnu/clojure/gnunet/crypto.clj b/src/org/gnu/clojure/gnunet/crypto.clj
new file mode 100644
index 0000000..eb1283b
--- /dev/null
+++ b/src/org/gnu/clojure/gnunet/crypto.clj
@@ -0,0 +1,15 @@
+(ns org.gnu.clojure.gnunet.crypto)
+
+(defn generate-rsa-keypair
+  "Generate a 2048 bit RSA keypair."
+  []
+  (let [rsa (java.security.KeyPairGenerator/getInstance "RSA")
+        spec (java.security.spec.RSAKeyGenParameterSpec. 2048 (bigint 257))]
+    (.initialize rsa spec)
+    (.generateKeyPair rsa)))
+
+(defn sha-512
+  "Compute the SHA-512 digest of a sequence of bytes."
+  [x]
+  (let [sha (java.security.MessageDigest/getInstance "SHA-512")]
+    (.digest sha (byte-array x))))
\ No newline at end of file
diff --git a/src/org/gnu/clojure/gnunet/hello.clj b/src/org/gnu/clojure/gnunet/hello.clj
index a8392db..b024f63 100644
--- a/src/org/gnu/clojure/gnunet/hello.clj
+++ b/src/org/gnu/clojure/gnunet/hello.clj
@@ -1,2 +1,29 @@
-(ns org.gnu.clojure.gnunet.hello)
+(ns org.gnu.clojure.gnunet.hello
+  (:use (org.gnu.clojure.gnunet message identity)))
 
+(def message-type-hello 16)
+
+(defn encode-transport
+  [transport]
+  (concat
+    (.getBytes (:name transport) "UTF-8")
+    (list (byte 0))
+    (encode-int32 (count (:encoded-address transport)))
+    (encode-int64 (.getTime (:expiration transport)))
+    (:encoded-address transport)))
+
+(defn encode-hello
+  "Encode a hello message."
+  [public-key transports]
+  (let [padding (encode-int32 0)
+        encoded-key (encode-rsa-public-key public-key)
+        encoded-transports (mapcat encode-transport transports)
+        size (+ header-size
+               (count padding)
+               (count encoded-key)
+               (count encoded-transports))]
+    (concat
+      (encode-header size message-type-hello)
+      padding
+      encoded-key
+      encoded-transports)))
diff --git a/src/org/gnu/clojure/gnunet/identity.clj b/src/org/gnu/clojure/gnunet/identity.clj
index 7eb3e03..f6cecfd 100644
--- a/src/org/gnu/clojure/gnunet/identity.clj
+++ b/src/org/gnu/clojure/gnunet/identity.clj
@@ -1,47 +1,30 @@
-(ns org.gnu.clojure.gnunet.identity)
+(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 bigendian."
+  "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-short
-  "Convert a short to a sequence of bytes in bigendian."
-  [x]
-  (list (byte (quot x 256)) (byte (rem x 256))))
-
 (defn encode-rsa-public-key
-  "Convert an RSA public key to a sequence of bytes in gnunet format"
+  "Convert an RSA public key to a sequence of bytes in gnunet format."
   [key]
   (let [modulus (encode-bigint (.getModulus key)) 
         modulus-len (count modulus)
         exponent (encode-bigint (.getPublicExponent key))
         exponent-len (count exponent)]
     (concat
-      (encode-short (+ modulus-len exponent-len 4))
-      (encode-short modulus-len)
+      (encode-int16 (+ modulus-len exponent-len 4))
+      (encode-int16 modulus-len)
       modulus
       exponent
-      (encode-short 0))))
-
-(defn generate-rsa-keypair
-  "Generate a 2048 bit RSA keypair"
-  []
-  (let [rsa (java.security.KeyPairGenerator/getInstance "RSA")
-        spec (java.security.spec.RSAKeyGenParameterSpec. 2048 (bigint 257))]
-    (.initialize rsa spec)
-    (.generateKeyPair rsa)))
-
-(defn sha-512
-  [x]
-  (let [sha (java.security.MessageDigest/getInstance "SHA-512")]
-    (.digest sha (byte-array x))))
+      (encode-int16 0))))
 
 (defn generate-id
-  "Generate the SHA-512 hash of the encoded public key"
+  "Generate the SHA-512 digest of the encoded public key."
   [keypair]
   (sha-512 (encode-rsa-public-key (.getPublic keypair))))
diff --git a/src/org/gnu/clojure/gnunet/message.clj b/src/org/gnu/clojure/gnunet/message.clj
new file mode 100644
index 0000000..9d0b74d
--- /dev/null
+++ b/src/org/gnu/clojure/gnunet/message.clj
@@ -0,0 +1,25 @@
+(ns org.gnu.clojure.gnunet.message)
+
+(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))))
+
+(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))))
+
+(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))))
+
+(defn encode-header
+  "Encode a gnunet message header."
+  [size message-type]
+  (concat
+    (encode-int16 size)
+    (encode-int16 message-type)))
+
+(def header-size (count (encode-header 0 0)))
\ No newline at end of file