GroupOSCORESubResourceNum.java

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package se.sics.ace.oscore.rs.oscoreGroupManager;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.californium.core.CoapResource;
import org.eclipse.californium.core.coap.CoAP;
import org.eclipse.californium.core.coap.Request;
import org.eclipse.californium.core.coap.Response;
import org.eclipse.californium.core.server.resources.CoapExchange;

import com.upokecenter.cbor.CBORObject;

import se.sics.ace.AceException;
import se.sics.ace.Constants;
import se.sics.ace.GroupcommErrors;
import se.sics.ace.GroupcommParameters;
import se.sics.ace.coap.CoapReq;
import se.sics.ace.oscore.GroupInfo;

/**
 * Definition of the Group OSCORE group-membership sub-resource /num
 */
public class GroupOSCORESubResourceNum extends CoapResource {
	
	private Map<String, GroupInfo> existingGroupInfo = new HashMap<>();
	
	/**
     * Constructor
     * @param resId  the resource identifier
     * @param existingGroupInfo  the set of information of the existing OSCORE groups
     */
    public GroupOSCORESubResourceNum(String resId, Map<String, GroupInfo> existingGroupInfo) {
        
        // set resource identifier
        super(resId);
        
        // set display name
        getAttributes().setTitle("Group OSCORE Group-Membership Sub-Resource \"num\" " + resId);
        
        this.existingGroupInfo = existingGroupInfo;
        
    }

    @Override
    public void handleGET(CoapExchange exchange) {
    	System.out.println("GET request reached the GM");
    	
    	// Retrieve the entry for the target group, using the last path segment of
    	// the URI path as the name of the OSCORE group
    	GroupInfo targetedGroup = existingGroupInfo.get(this.getParent().getName());
    	
    	// This should never happen if existing groups are maintained properly
    	if (targetedGroup == null) {
        	exchange.respond(CoAP.ResponseCode.SERVICE_UNAVAILABLE,
        					 "Error when retrieving material for the OSCORE group");
        	return;
    	}
    	
    	String groupName = targetedGroup.getGroupName();
    	
    	// This should never happen if active groups are maintained properly
  		if (!groupName.equals(this.getParent().getName())) {
    	exchange.respond(CoAP.ResponseCode.SERVICE_UNAVAILABLE,
    					 "Error when retrieving material for the OSCORE group");
			return;
		}
    	
    	String subject = null;
    	Request request = exchange.advanced().getCurrentRequest();
        
        try {
			subject = CoapReq.getInstance(request).getSenderId();
		} catch (AceException e) {
		    System.err.println("Error while retrieving the client identity: " + e.getMessage());
		}
        if (subject == null) {
        	// At this point, this should not really happen,
        	// due to the earlier check at the Token Repository
        	exchange.respond(CoAP.ResponseCode.UNAUTHORIZED,
        					 "Unauthenticated client tried to get access");
        	return;
        }
    	
    	if (!targetedGroup.isGroupMember(subject)) {	
    		// The requester is not a current group member.
    		CBORObject responseMap = CBORObject.NewMap();
    		
    		CBORObject aceGroupcommError = CBORObject.NewMap();
    		aceGroupcommError.Add(0, GroupcommErrors.ONLY_FOR_GROUP_MEMBERS);
    		responseMap.Add(Constants.PROBLEM_DETAIL_ACE_GROUPCOMM_ERROR, aceGroupcommError);
    		responseMap.Add(Constants.PROBLEM_DETAIL_KEY_TITLE, GroupcommErrors.DESCRIPTION[GroupcommErrors.ONLY_FOR_GROUP_MEMBERS]);
    		
    		byte[] responsePayload = responseMap.EncodeToBytes();
    		exchange.respond(CoAP.ResponseCode.FORBIDDEN,
    						 responsePayload,
    						 Constants.APPLICATION_CONCISE_PROBLEM_DETAILS_CBOR);
    		
    		return;
    	}
        	
    	// Respond to the Version Request
        
    	CBORObject myResponse = CBORObject.FromObject(targetedGroup.getVersion());
    	
    	byte[] responsePayload = myResponse.EncodeToBytes();
    	
    	Response coapResponse = new Response(CoAP.ResponseCode.CONTENT);
    	coapResponse.setPayload(responsePayload);
    	coapResponse.getOptions().setContentFormat(Constants.APPLICATION_CBOR);

    	exchange.respond(coapResponse);

    }
    
}