Changeset a3e16614

Timestamp:

Nov 8, 2015 6:30:51 PM (5 years ago)

Author:

zzz <zzz@…>

Branches:

master

Children:

e120a8a

Parents:

bdde11c

Message:

SSU: Prep for extended options

Location:

router/java/src/net/i2p/router/transport/udp

Files:

• PacketBuilder.java (modified) (4 diffs)
• UDPPacket.java (modified) (1 diff)
• UDPPacketReader.java (modified) (3 diffs)

router/java/src/net/i2p/router/transport/udp/PacketBuilder.java

@@ -784 +784 @@
      */
     public UDPPacket buildSessionRequestPacket(OutboundEstablishState state) {
+        // TODO
+        //byte[] options = new byte[3];
+        //UDPPacket packet = buildPacketHeader(SESSION_REQUEST_FLAG_BYTE, options);
         UDPPacket packet = buildPacketHeader(SESSION_REQUEST_FLAG_BYTE);
         DatagramPacket pkt = packet.getPacket();
         byte data[] = pkt.getData();
-        int off = HEADER_SIZE;
+        int off = HEADER_SIZE; // + 1 + options.length;
 
         byte toIP[] = state.getSentIP();
@@ -1434 +1437 @@
      *  Create a new packet and add the flag byte and the time stamp.
      *  Caller should add data starting at HEADER_SIZE.
-     *  At this point, adding support for extended options and rekeying is unlikely,
-     *  but if we do, we'll have to change this.
+     *  Does not include extended options or rekeying.
      *
      *  @param flagByte contains type and flags
@@ -1441 +1443 @@
      */
     private UDPPacket buildPacketHeader(byte flagByte) {
+        return buildPacketHeader(flagByte, null);
+    }
+
+    /**
+     *  Create a new packet and add the flag byte and the time stamp.
+     *  Caller should add data starting at HEADER_SIZE.
+     *  (if extendedOptions != null, at HEADER_SIZE + 1 + extendedOptions.length)
+     *  Does not include rekeying.
+     *
+     *  @param flagByte contains type and flags
+     *  @param extendedOptions May be null. If non-null, we will add the associated flag here.
+     *                         255 bytes max.
+     *  @since 0.9.24
+     */
+    private UDPPacket buildPacketHeader(byte flagByte, byte[] extendedOptions) {
         UDPPacket packet = UDPPacket.acquire(_context, false);
         byte data[] = packet.getPacket().getData();
@@ -1447 +1464 @@
         
         // header
+        if (extendedOptions != null)
+            flagByte |= UDPPacket.HEADER_FLAG_EXTENDED_OPTIONS;
         data[off] = flagByte;
         off++;
         long now = (_context.clock().now() + 500) / 1000;
         DataHelper.toLong(data, off, 4, now);
-        // todo: add support for rekeying and extended options
+        // todo: add support for rekeying
+        // extended options
+        if (extendedOptions != null) {
+            off+= 4;
+            int len = extendedOptions.length;
+            if (len > 255)
+                throw new IllegalArgumentException();
+            data[off++] = (byte) len;
+            System.arraycopy(extendedOptions, 0, data, off, len);
+        }
         return packet;
     }

router/java/src/net/i2p/router/transport/udp/UDPPacket.java

@@ -90 +90 @@
     public static final int PAYLOAD_TYPE_SESSION_DESTROY = 8;
     
+    // various flag fields for use in the header
+    /**
+     *  Defined in the spec from the beginning, Unused
+     *  @since 0.9.24
+     */
+    public static final byte HEADER_FLAG_REKEY = (1 << 3);
+    /**
+     *  Defined in the spec from the beginning, Used starting in 0.9.24
+     *  @since 0.9.24
+     */
+    public static final byte HEADER_FLAG_EXTENDED_OPTIONS = (1 << 2);
+
     // various flag fields for use in the data packets
     public static final byte DATA_FLAG_EXPLICIT_ACK = (byte)(1 << 7);
     public static final byte DATA_FLAG_ACK_BITFIELDS = (1 << 6);
-    // unused
+    /** unused */
     public static final byte DATA_FLAG_ECN = (1 << 4);
     public static final byte DATA_FLAG_WANT_ACKS = (1 << 3);
     public static final byte DATA_FLAG_WANT_REPLY = (1 << 2);
-    // unused
+    /** unused */
     public static final byte DATA_FLAG_EXTENDED = (1 << 1);
     

router/java/src/net/i2p/router/transport/udp/UDPPacketReader.java

@@ -68 +68 @@
     }
     
-    /** does this packet include rekeying data? */
-    public boolean readRekeying() {
-        return (_message[_payloadBeginOffset] & (1 << 3)) != 0;
-    }
-    
-    public boolean readExtendedOptionsIncluded() {
-        return (_message[_payloadBeginOffset] & (1 << 2)) != 0;
+    /**
+     * Does this packet include rekeying data in the header?
+     * Unused, should always be false.
+     */
+    public boolean isRekeyingIncluded() {
+        return (_message[_payloadBeginOffset] & UDPPacket.HEADER_FLAG_REKEY) != 0;
+    }
+    
+    /**
+     * Does this packet include extended options in the header?
+     */
+    public boolean isExtendedOptionsIncluded() {
+        return (_message[_payloadBeginOffset] & UDPPacket.HEADER_FLAG_EXTENDED_OPTIONS) != 0;
     }
     
@@ -82 +88 @@
     }
     
-    public void readKeyingMaterial(byte target[], int targetOffset) {
-        if (!readRekeying())
-            throw new IllegalStateException("This packet is not rekeying!");
-        System.arraycopy(_message, _payloadBeginOffset + 1 + 4, target, targetOffset, KEYING_MATERIAL_LENGTH);
+    /**
+     * Returns rekeying data (64 bytes), or null if none.
+     * Unused, should always return null.
+     *
+     * @deprecated unused
+     */
+    @Deprecated
+    public byte[] readKeyingMaterial() {
+        if (!isRekeyingIncluded())
+            return null;
+        byte[] rv = new byte[KEYING_MATERIAL_LENGTH];
+        System.arraycopy(_message, _payloadBeginOffset + 1 + 4, rv, 0, KEYING_MATERIAL_LENGTH);
+        return rv;
+    }
+    
+    /**
+     * Returns extended option data, 0-255 bytes, or null if none.
+     *
+     * @return extended options or null if none is included
+     * @since 0.9.24
+     */
+    public byte[] readExtendedOptions() {
+        if (!isExtendedOptionsIncluded())
+            return null;
+        int offset = _payloadBeginOffset + 1 + 4;
+        if (isRekeyingIncluded())
+            offset += KEYING_MATERIAL_LENGTH;
+        int optionsSize = _message[offset++] & 0xff;
+        byte[] rv = new byte[optionsSize];
+        System.arraycopy(_message, offset, rv, 0, optionsSize);
+        return rv;
     }
     
@@ -91 +124 @@
     private int readBodyOffset() {
         int offset = _payloadBeginOffset + 1 + 4;
-        if (readRekeying())
+        if (isRekeyingIncluded())
             offset += KEYING_MATERIAL_LENGTH;
-        if (readExtendedOptionsIncluded()) {
-            int optionsSize = (int)DataHelper.fromLong(_message, offset, 1);
+        if (isExtendedOptionsIncluded()) {
+            int optionsSize = _message[offset] & 0xff;
             offset += optionsSize + 1;
         }