From a4c0d3d6d878da55435cb9d9cc8cff6199644199 Mon Sep 17 00:00:00 2001
From: Peter Palfrader <peter@palfrader.org>
Date: Sun, 19 Oct 2003 15:08:35 +0000
Subject: Support random path creation

---
 .../noreply/fancydress/directory/Directory.java    | 230 ++++++++++++++++++---
 1 file changed, 199 insertions(+), 31 deletions(-)

(limited to 'src/org/noreply/fancydress/directory/Directory.java')

diff --git a/src/org/noreply/fancydress/directory/Directory.java b/src/org/noreply/fancydress/directory/Directory.java
index f2eda8c..ff0cfdf 100644
--- a/src/org/noreply/fancydress/directory/Directory.java
+++ b/src/org/noreply/fancydress/directory/Directory.java
@@ -24,6 +24,12 @@ import java.util.*;
  * @see Server
  */
 public class Directory {
+	/**
+	 * directory version we understand.
+	 */
+
+	private static final String DIRECTORY_VERSION = "0.2";
+
 	/**
 	 * Hash holding all Servers.
 	 *
@@ -37,35 +43,27 @@ public class Directory {
 	private Hashtable byName;
 
 	/**
-	 * Possibly add a new server descriptor to the directory.
+	 * Useable servers.
 	 *
-	 * This method adds a server desccriptor to the directory if it
-	 *  - conforms to the syntax specified.
-	 *  - the server is not yet known or it's identity key matches the key of the already known ServerDescriptor.
+	 * A server is useable if it understands PacketVersions that we understand
+	 * and has a serverdescriptor that is useable right now.
+	 */
+	private Server[] useableServers;
+
+	/**
+	 * Recommended servers.
+	 */
+	private Server[] recommendedServers;
+	
+	/*
+	 * matrix of friends.
 	 *
-	 * @param server a DirectoryMessage consisting of one of more sections.  At 'Server' section needs to be present.
-	 * @throws Mix3BadServerFormatException if a section is syntactially invalid and the error cannot be ignored.
-	 * @throws Mix3BadServerSignatureException if the server descriptor's signature is invalid.
+	 * (a, b) are friends, if a can send messages to b.
 	 */
-	private void addServerDescriptor(DirectoryMessage server) throws Mix3BadServerFormatException, Mix3BadServerSignatureException {
-		try {
-			ServerDescriptor sd = new ServerDescriptor(server);
-			String key = sd.getNickname().toLowerCase();
-			if (byName.containsKey(key)) {
-				Server s = (Server) byName.get(key);
-				try {
-					s.addDescriptor(sd);
-				} catch (Mix3BadServerFormatException e) {
-					System.err.println("Ignoring Descriptor with different identity for "+key);
-				}
-			} else {
-				Server s = new Server(sd);
-				byName.put(key, s);
-			}
-		} catch (Mix3BadServerUnrecognizedVersionException e) {
-			System.err.println("Ignoring unregonized version");
-		}
-	}
+	/*
+	private boolean[][] friends;
+	*/
+
 
 	/**
 	 * Create a directory from an entire DirectoryMessage.
@@ -82,11 +80,87 @@ public class Directory {
 	 */
 	public Directory(DirectoryMessage m, boolean checkDirectorySignature) throws
 		Mix3BadDirectorySignatureException,
+		Mix3BadDirectoryFormatException,
 		Mix3BadServerFormatException,
 		Mix3BadServerSignatureException
 	{
 		byName = new Hashtable();
 
+
+		parseDirectory(m, checkDirectorySignature);
+
+
+		Collection all = byName.values();
+		ArrayList useable = new ArrayList();
+		for (Iterator i = all.iterator(); i.hasNext(); ) {
+			Server s = (Server) i.next();
+			if (s.isUseable())
+				useable.add(s);
+		}
+		useableServers = (Server[]) useable.toArray( new Server[useable.size()] );
+
+
+		ArrayList recommended = new ArrayList();
+		for (int i=0; i<useableServers.length; i++)
+			if (useableServers[i].isRecommended())
+				recommended.add(useableServers[i]);
+		recommendedServers = (Server[]) recommended.toArray( new Server[recommended.size()] );
+	}
+
+
+
+	/**
+	 * Possibly add a new server descriptor to the directory.
+	 *
+	 * This method adds a server desccriptor to the directory if it
+	 *  - conforms to the syntax specified.
+	 *  - the server is not yet known or it's identity key matches the key of the already known ServerDescriptor.
+	 *
+	 * @param server a DirectoryMessage consisting of one of more sections.  At 'Server' section needs to be present.
+	 * @throws Mix3BadServerFormatException if a section is syntactially invalid and the error cannot be ignored.
+	 * @throws Mix3BadServerSignatureException if the server descriptor's signature is invalid.
+	 */
+	private void addServerDescriptor(DirectoryMessage server) throws Mix3BadServerFormatException, Mix3BadServerSignatureException {
+		ServerDescriptor sd;
+		try {
+			sd = new ServerDescriptor(server);
+		} catch (Mix3BadServerUnrecognizedVersionException e) {
+			System.err.println("Ignoring unregonized version");
+			return;
+		}
+		String key = sd.getNickname().toLowerCase();
+		if (byName.containsKey(key)) {
+			Server s = (Server) byName.get(key);
+			try {
+				s.addDescriptor(sd);
+			} catch (Mix3BadServerFormatException e) {
+				System.err.println("Ignoring Descriptor with different identity for "+key);
+			}
+		} else {
+			Server s = new Server(sd);
+			byName.put(key, s);
+		}
+	}
+
+
+	private void parseDirectory(DirectoryMessage m, boolean checkDirectorySignature) throws
+		Mix3BadDirectorySignatureException,
+		Mix3BadDirectoryFormatException,
+		Mix3BadServerFormatException,
+		Mix3BadServerSignatureException
+	{
+		DirectorySection directorySection = m.getSection("Directory");
+		if (directorySection == null)
+			throw new Mix3BadDirectoryFormatException("No Directory section found.");
+
+		DirectoryEntry versionEntry = directorySection.getEntry("Version");
+		if (versionEntry == null)
+			throw new Mix3BadDirectoryFormatException("No Version in Directory section found.");
+		if (! versionEntry.getValue().equals(DIRECTORY_VERSION))
+			throw new Mix3BadDirectoryFormatException("Directory Version "+versionEntry+" not recognized.");
+
+		/* FIXME: check validity (date range) */
+
 		if (checkDirectorySignature)
 			checkSignature(m);
 		DirectoryMessage server = null;
@@ -102,27 +176,38 @@ public class Directory {
 		}
 		if (server != null)
 			addServerDescriptor(server);
+
+		DirectoryEntry recommendedServersEntry = directorySection.getEntry("Recommended-Servers");
+		if (recommendedServersEntry == null)
+			throw new Mix3BadDirectorySignatureException("No Recommended-Servers in Directory section found.");
+		String[] recommendedServers = Util.tokenize( recommendedServersEntry.getValue(), ',');
+		for (int i=0; i<recommendedServers.length; i++) {
+			Server s = getServer(recommendedServers[i]);
+			if (s == null)
+				throw new Mix3BadDirectoryFormatException("Unkown nickname '"+recommendedServers[i]+"'in Recommended-Servers");
+			s.setRecommended();
+		}
 	}
 
 	/* FIXME: known directory servers should be passed as arguments */
 	/**
 	 * Check the signature of a type III directory.
 	 */
-	private void checkSignature(DirectoryMessage m) throws Mix3BadDirectorySignatureException {
+	private void checkSignature(DirectoryMessage m) throws Mix3BadDirectorySignatureException, Mix3BadDirectoryFormatException {
 		/* FIXME: handle more than one signature block,
 		 */
 
 		DirectorySection signatureSection = m.getSection("Signature");
 		if (signatureSection == null)
-			throw new Mix3BadDirectorySignatureException("No Signature section found.");
+			throw new Mix3BadDirectoryFormatException("No Signature section found.");
 
 		DirectoryEntry signatureEntry = signatureSection.getEntry("DirectorySignature");
 		if (signatureEntry == null)
-			throw new Mix3BadDirectorySignatureException("No DirectorySignature in Signature section found.");
+			throw new Mix3BadDirectoryFormatException("No DirectorySignature in Signature section found.");
 
 		DirectoryEntry identityEntry = signatureSection.getEntry("DirectoryIdentity");
 		if (identityEntry == null)
-			throw new Mix3BadDirectorySignatureException("No DirectoryIdentity in Signature section found.");
+			throw new Mix3BadDirectoryFormatException("No DirectoryIdentity in Signature section found.");
 
 		byte[] signature = Base64.decode(signatureEntry.getValue());
 		byte[] identity = Base64.decode(identityEntry.getValue());
@@ -131,7 +216,6 @@ public class Directory {
 		cleanedDirectory.blindValue("Signature","DirectoryDigest");
 		cleanedDirectory.blindValue("Signature","DirectorySignature");
 
-		/* FIXME: what if identity is no valid key? */
 		RSAPublicKey identityKey = new RSAPublicKey(identity);
 		boolean verifies;
 		try {
@@ -145,6 +229,9 @@ public class Directory {
 
 	/**
 	 * Get a server by nickname.
+	 *
+	 * @param name nickname of the requested server
+	 * @return server specified by the nickname or null if no such server exists
 	 */
 	public Server getServer(String name) {
 			String key = name.toLowerCase();
@@ -152,4 +239,85 @@ public class Directory {
 				return (Server) byName.get(key);
 			return null;
 	}
+
+	/*
+	 * Get current server descriptor of useable servers.
+	 *
+	 * A server is useable if it understands PacketVersions that we understand
+	 * and has a serverdescriptor that is useable right now.
+	 *
+	 * @return server descriptor of useable servers
+	 */
+	/*
+	private Server[] getUseableServers() {
+		return useableServers;
+	}
+	*/
+
+	/**
+	 * Get server descriptor of all recommended servers that are useable.
+	 *
+	 * @return server descriptor recommended servers
+	 * @see #getUseableServers
+	 */
+	public Server[] getRecommendedServers() {
+		return recommendedServers;
+	}
+
+	/**
+	 * Check if server a can talk to server b.
+	 *
+	 * A server can talk to another one if they have MMTP/Outgoing and
+	 * MMTP/Incoming sections respectively and speak a common MMTP version.
+	 *
+	 * FIXME: check Allow/Deny ACLs
+	 *
+	 * @param a server a
+	 * @param b server b
+	 * @return whether a can send messages to b
+	 */
+	public boolean areFriends(Server a, Server b) {
+		ServerDescriptor aa,bb;
+		
+		try {
+			aa = a.getDescriptor();
+		} catch (Mix3NoServerDescriptorException e) {
+			throw new Error(a.getNickname()+" should have a valid ServerDescriptor.", e);
+		}
+		try {
+			bb = b.getDescriptor();
+		} catch (Mix3NoServerDescriptorException e) {
+			throw new Error(b.getNickname()+" should have a valid ServerDescriptor.", e);
+		}
+
+		OutgoingMMTPSection out = aa.getOutgoingMMTPSection();
+		IncomingMMTPSection in = bb.getIncomingMMTPSection();
+
+		if (out == null || in == null)
+			return false;
+		String[] inP = in.getProtocols();
+		String[] outP = out.getProtocols();
+		for (int i=0; i<inP.length; i++)
+			for (int o=0; o<outP.length; o++)
+				if (inP[i].equals(outP[o]))
+					return true;
+		return false;
+	}
+
+	/*
+	 * Build a matrix of friends.
+	 *
+	 * (a, b) are friends, if a can send messages to b.
+	 */
+	/*
+	private void buildFriendsMatrix() {
+		friends = new boolean[useableServers.length][useableServers.length];
+		for (int i=0; i<useableServers.length; i++)
+			for (int j=0; j<useableServers.length; j++)
+				if (i==j)
+					friends[i][j] = true;
+				else
+					friends[i][j] = areFriends(useableServers[i], useableServers[j]);
+	}
+	 */
 }
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