started documenting p3GossipDiscovery

libretroshare/src/gossipdiscovery/p3gossipdiscovery.cc

@@ -312,9 +312,13 @@ void p3discovery2::sendOwnContactInfo(const RsPeerId &sslid)
 	if (mPeerMgr->getOwnNetStatus(detail))
 	{
 		RsDiscContactItem *pkt = new RsDiscContactItem();
+
 		/* Cyril: we dont send our own IP to an hidden node. It will not use it
-		 *   anyway. */
+		 * anyway. Furthermore, a Tor node is not supposed to have any mean to send the IPs of his friend nodes
+ 		 * to other nodes. This would be a very serious security risk.    */
+
 		populateContactInfo(detail, pkt, !rsPeers->isHiddenNode(sslid));
+
 		/* G10h4ck: sending IP information also to hidden nodes has proven very
 		 *   helpful in the usecase of non hidden nodes, that share a common
 		 *   hidden trusted node, to discover each other IP.
@@ -323,7 +327,6 @@ void p3discovery2::sendOwnContactInfo(const RsPeerId &sslid)
 		 *   permission matrix. Disabling this instead will make life more
 		 *   difficult for average user, that moreover whould have no way to
 		 *   revert an hardcoded policy. */
-		//populateContactInfo(detail, pkt, true);
 
 		pkt->version = RS_HUMAN_READABLE_VERSION;
 		pkt->PeerId(sslid);
@@ -406,7 +409,12 @@ void p3discovery2::recvOwnContactInfo(const RsPeerId &fromId, const RsDiscContac
 	// It is important that PGPList is received after the OwnContactItem.
 	// This should happen, but is not enforced by the protocol.
 
-	// start peer list exchange.
+	// Start peer list exchange, if discovery is enabled
+
+    peerState ps;
+    mPeerMgr->getOwnNetStatus(ps);
+
+    if(ps.vs_disc != RS_VS_DISC_OFF)
 		sendPGPList(fromId);
 
 	// Update mDiscStatus.
@@ -520,10 +528,17 @@ void p3discovery2::sendPGPList(const RsPeerId &toId)
 
 	pkt->mode = RsGossipDiscoveryPgpListMode::FRIENDS;
 
-	std::map<RsPgpId, DiscPgpInfo>::const_iterator it;
+	for(auto it = mFriendList.begin(); it != mFriendList.end(); ++it)
-	for(it = mFriendList.begin(); it != mFriendList.end(); ++it)
+	{
+        // Check every friend, and only send his PGP key if the friend tells that he wants discovery. Because this info is done on the level of locations,
+        // we check each location and only send the key if at least one location allows it.
+
+        for(auto it2(it->second.mSslIds.begin());it2!=it->second.mSslIds.end();++it2)
+            if(it2->second.mDiscStatus != RS_VS_DISC_OFF)
             {
 				pkt->pgpIdSet.ids.insert(it->first);
+                break;
+            }
 	}
 
 	pkt->PeerId(toId);

libretroshare/src/gossipdiscovery/p3gossipdiscovery.h

@@ -22,6 +22,57 @@
  *******************************************************************************/
 #pragma once
 
+//
+// p3GossipDiscovery is reponsible for facilitating the circulation of public keys between friend nodes.
+//
+// The service locally holds a cache that stores:
+//     * the list of friend profiles, in each of which the list of locations with their own discovery flag (which means whether they allow discovery or not)
+//     * the list of friend nodes, with their version number
+//
+// Data flow
+// =========
+//
+//  statusChange(std::list<pqiServicePeer>&)         // called by pqiMonitor when peers are added,removed, or recently connected
+//       |
+//       +---- sendOwnContactInfo(RsPeerId)          // [On connection]      sends own PgpId, discovery flag, list of own signed GxsIds
+//       |               |
+//       |               +---->[to friend]
+//       |
+//       +---- addFriend() / removeFriend()          // [New/Removed friend] updates the list of friends, along with their own discovery flag
+//
+//  tick()
+//   |
+//   +------ handleIncoming()
+//                  |
+//                  +-- recvOwnContactInfo(RsPeerId)   // update location, IP addresses of a peer.
+//                  |            |
+//                  |            +------(if the peer has short_invite flag)
+//                  |            |                      |
+//                  |            |                      +---------requestPGPKey()->[to friend]      // requests the full PGP public key, so as to be
+//                  |            |                                                                  // able to validate connections.
+//                  |            |
+//                  |            +------(if disc != RS_VS_DISC_OFF)
+//                  |                                   |
+//                  |                                   +---------sendPgpList()->[to friend]        // sends own list of friend profiles for which at least one location
+//                  |                                                                               // accepts discovery
+//                  +-- processContactInfo(item->PeerId(), contact);
+//                  |
+//                  +-- recvIdentityList(Gxs Identity List)
+//                  |
+//                  +-- recvPGPCertificate(item->PeerId(), pgpkey);
+//                  |
+//                  +-- processPGPList(pgplist->PeerId(), pgplist);
+//                  |
+//                  +-- recvPGPCertificateRequest(pgplist->PeerId(), pgplist);
+//
+// Notes:
+//    * Tor nodes never send their own IP, and normal nodes never send their IP to Tor nodes either.
+//      A Tor node may accidentally know the IP of a normal node when it adds its certificate. However, the IP is dropped and not saved in this case.
+//      Generally speaking, no IP information should leave or transit through a Tor node.
+//
+//    * the decision to call recvOwnContactInfo() or processContactInfo() depends on whether the item's peer id is the one the info is about. This is
+//      a bit unsafe. We should probably have to different items here especially if the information is not exactly the same.
+//
 #include <memory>
 
 #include "retroshare/rsgossipdiscovery.h"
@@ -38,7 +89,7 @@ class p3ServiceControl;
 
 struct DiscSslInfo
 {
-	DiscSslInfo() : mDiscStatus(0) {}
+	DiscSslInfo() : mDiscStatus(RS_VS_DISC_OFF) {}	// default is to not allow discovery, until the peer tells about it
 	uint16_t mDiscStatus;
 };
 
@@ -123,7 +174,6 @@ private:
 	void rsEventsHandler(const RsEvent& event);
 	RsEventsHandlerId_t mRsEventsHandle;
 
-
 	p3PeerMgr *mPeerMgr;
 	p3LinkMgr *mLinkMgr;
 	p3NetMgr  *mNetMgr;