rename SAMENESS to DIFFERENCE which is less confusing

controller/EmbeddedNetworkController.cpp

@@ -255,8 +255,8 @@ static json _renderRule(ZT_VirtualNetworkRule &rule)
 			r["start"] = (unsigned int)rule.v.frameSize[0];
 			r["end"] = (unsigned int)rule.v.frameSize[1];
 			break;
-		case ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS:
-			r["type"] = "MATCH_TAGS_SAMENESS";
+		case ZT_NETWORK_RULE_MATCH_TAGS_DIFFERENCE:
+			r["type"] = "MATCH_TAGS_DIFFERENCE";
 			r["not"] = ((rule.t & 0x80) != 0);
 			r["id"] = rule.v.tag.id;
 			r["value"] = rule.v.tag.value;
@@ -431,8 +431,8 @@ static bool _parseRule(json &r,ZT_VirtualNetworkRule &rule)
 		rule.v.frameSize[0] = (uint16_t)(_jI(r["start"],0ULL) & 0xffffULL);
 		rule.v.frameSize[1] = (uint16_t)(_jI(r["end"],(uint64_t)rule.v.frameSize[0]) & 0xffffULL);
 		return true;
-	} else if (t == "MATCH_TAGS_SAMENESS") {
-		rule.t |= ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS;
+	} else if (t == "MATCH_TAGS_DIFFERENCE") {
+		rule.t |= ZT_NETWORK_RULE_MATCH_TAGS_DIFFERENCE;
 		rule.v.tag.id = (uint32_t)(_jI(r["id"],0ULL) & 0xffffffffULL);
 		rule.v.tag.value = (uint32_t)(_jI(r["value"],0ULL) & 0xffffffffULL);
 		return true;

include/ZeroTierOne.h

@@ -625,7 +625,7 @@ enum ZT_VirtualNetworkRuleType
 	/**
 	 * Match if local and remote tags differ by no more than value, use 0 to check for equality
 	 */
-	ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS = 51,
+	ZT_NETWORK_RULE_MATCH_TAGS_DIFFERENCE = 51,
 
 	/**
 	 * Match if local and remote tags ANDed together equal value.

node/Capability.hpp

@@ -38,9 +38,6 @@ class RuntimeEnvironment;
 /**
  * A set of grouped and signed network flow rules
  *
- * The use of capabilities implements capability-based security on ZeroTIer
- * virtual networks for efficient and manageable network micro-segmentation.
- *
  * On the sending side the sender does the following for each packet:
  *
  * (1) Evaluates its capabilities in ascending order of ID to determine
@@ -49,16 +46,12 @@ class RuntimeEnvironment;
  *     receving peer ("presents" it).
  * (3) The sender then sends the packet.
  *
- * On the receiving side the receiver does the following for each packet:
- *
- * (1) Evaluates the capabilities of the sender (that the sender has
- *     presented) to determine if it should received this packet.
- * (2) Evaluates its own capabilities to determine if it should receive
- *     this packet.
- * (3) If both check out, it receives the packet.
+ * On the receiving side the receiver evaluates the capabilities presented
+ * by the sender. If any valid un-expired capability allows this packet it
+ * is accepted.
  *
- * Note that rules in capabilities can do other things as well such as TEE
- * or REDIRECT packets. See filter code and ZT_VirtualNetworkRule.
+ * Note that this is after evaluation of network scope rules and only if
+ * network scope rules do not deliver an explicit match.
  */
 class Capability
 {
@@ -255,7 +248,7 @@ public:
 					b.append((uint16_t)rules[i].v.frameSize[0]);
 					b.append((uint16_t)rules[i].v.frameSize[1]);
 					break;
-				case ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS:
+				case ZT_NETWORK_RULE_MATCH_TAGS_DIFFERENCE:
 				case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_AND:
 				case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_OR:
 				case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_XOR:
@@ -336,7 +329,7 @@ public:
 					rules[ruleCount].v.frameSize[0] = b.template at<uint16_t>(p);
 					rules[ruleCount].v.frameSize[1] = b.template at<uint16_t>(p + 2);
 					break;
-				case ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS:
+				case ZT_NETWORK_RULE_MATCH_TAGS_DIFFERENCE:
 				case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_AND:
 				case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_OR:
 				case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_XOR:

node/Network.cpp

@@ -69,7 +69,7 @@ static const char *_rtn(const ZT_VirtualNetworkRuleType rt)
 		case ZT_NETWORK_RULE_MATCH_IP_DEST_PORT_RANGE: return "MATCH_IP_DEST_PORT_RANGE";
 		case ZT_NETWORK_RULE_MATCH_CHARACTERISTICS: return "MATCH_CHARACTERISTICS";
 		case ZT_NETWORK_RULE_MATCH_FRAME_SIZE_RANGE: return "MATCH_FRAME_SIZE_RANGE";
-		case ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS: return "MATCH_TAGS_SAMENESS";
+		case ZT_NETWORK_RULE_MATCH_TAGS_DIFFERENCE: return "MATCH_TAGS_DIFFERENCE";
 		case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_AND: return "MATCH_TAGS_BITWISE_AND";
 		case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_OR: return "MATCH_TAGS_BITWISE_OR";
 		case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_XOR: return "MATCH_TAGS_BITWISE_XOR";
@@ -487,7 +487,7 @@ static int _doZtFilter(
 				thisRuleMatches = (uint8_t)((frameLen >= (unsigned int)rules[rn].v.frameSize[0])&&(frameLen <= (unsigned int)rules[rn].v.frameSize[1]));
 				FILTER_TRACE("%u %s %c %u in %u-%u -> %u",rn,_rtn(rt),(((rules[rn].t & 0x80) != 0) ? '!' : '='),frameLen,(unsigned int)rules[rn].v.frameSize[0],(unsigned int)rules[rn].v.frameSize[1],(unsigned int)thisRuleMatches);
 				break;
-			case ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS:
+			case ZT_NETWORK_RULE_MATCH_TAGS_DIFFERENCE:
 			case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_AND:
 			case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_OR:
 			case ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_XOR: {
@@ -510,13 +510,18 @@ static int _doZtFilter(
 						}
 					}
 					if (!rtv) {
-						thisRuleMatches = 0;
-						FILTER_TRACE("%u %s %c remote tag %u not found -> 0",rn,_rtn(rt),(((rules[rn].t & 0x80) != 0) ? '!' : '='),(unsigned int)rules[rn].v.tag.id);
+						if (inbound) {
+							thisRuleMatches = 0;
+							FILTER_TRACE("%u %s %c remote tag %u not found -> 0 (inbound side is strict)",rn,_rtn(rt),(((rules[rn].t & 0x80) != 0) ? '!' : '='),(unsigned int)rules[rn].v.tag.id);
+						} else {
+							thisRuleMatches = 1;
+							FILTER_TRACE("%u %s %c remote tag %u not found -> 1 (outbound side is not strict)",rn,_rtn(rt),(((rules[rn].t & 0x80) != 0) ? '!' : '='),(unsigned int)rules[rn].v.tag.id);
+						}
 					} else {
-						if (rt == ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS) {
-							const uint32_t sameness = (lt->value() > *rtv) ? (lt->value() - *rtv) : (*rtv - lt->value());
-							thisRuleMatches = (uint8_t)(sameness <= rules[rn].v.tag.value);
-							FILTER_TRACE("%u %s %c TAG %u local:%u remote:%u sameness:%u <= %u -> %u",rn,_rtn(rt),(((rules[rn].t & 0x80) != 0) ? '!' : '='),(unsigned int)rules[rn].v.tag.id,lt->value(),*rtv,sameness,(unsigned int)rules[rn].v.tag.value,thisRuleMatches);
+						if (rt == ZT_NETWORK_RULE_MATCH_TAGS_DIFFERENCE) {
+							const uint32_t diff = (lt->value() > *rtv) ? (lt->value() - *rtv) : (*rtv - lt->value());
+							thisRuleMatches = (uint8_t)(diff <= rules[rn].v.tag.value);
+							FILTER_TRACE("%u %s %c TAG %u local:%u remote:%u difference:%u<=%u -> %u",rn,_rtn(rt),(((rules[rn].t & 0x80) != 0) ? '!' : '='),(unsigned int)rules[rn].v.tag.id,lt->value(),*rtv,diff,(unsigned int)rules[rn].v.tag.value,thisRuleMatches);
 						} else if (rt == ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_AND) {
 							thisRuleMatches = (uint8_t)((lt->value() & *rtv) == rules[rn].v.tag.value);
 							FILTER_TRACE("%u %s %c TAG %u local:%.8x & remote:%.8x == %.8x -> %u",rn,_rtn(rt),(((rules[rn].t & 0x80) != 0) ? '!' : '='),(unsigned int)rules[rn].v.tag.id,lt->value(),*rtv,(unsigned int)rules[rn].v.tag.value,(unsigned int)thisRuleMatches);
@@ -675,22 +680,22 @@ int Network::filterIncomingPacket(
 	const unsigned int remoteTagCount = m.getAllTags(_config,remoteTagIds,remoteTagValues,ZT_MAX_NETWORK_TAGS);
 
 	switch (_doZtFilter(RR,false,_config,true,sourcePeer->address(),ztDest,macSource,macDest,frameData,frameLen,etherType,vlanId,_config.rules,_config.ruleCount,_config.tags,_config.tagCount,remoteTagIds,remoteTagValues,remoteTagCount)) {
-		case -1: return 0;
-		case 1: return 1;
-		case 2: return 2;
+		case -1: return 0; // DROP
+		case 1: return 1; // ACCEPT
+		case 2: return 2; // super-ACCEPT
 	}
 
 	Membership::CapabilityIterator mci(m);
 	const Capability *c;
 	while ((c = mci.next(_config))) {
-		switch(_doZtFilter(RR,false,_config,false,sourcePeer->address(),ztDest,macSource,macDest,frameData,frameLen,etherType,vlanId,c->rules(),c->ruleCount(),_config.tags,_config.tagCount,remoteTagIds,remoteTagValues,remoteTagCount)) {
-			case -1: return 0;
-			case 1: return 1;
-			case 2: return 2;
+		switch(_doZtFilter(RR,false,_config,true,sourcePeer->address(),ztDest,macSource,macDest,frameData,frameLen,etherType,vlanId,c->rules(),c->ruleCount(),_config.tags,_config.tagCount,remoteTagIds,remoteTagValues,remoteTagCount)) {
+			case -1: return 0; // DROP
+			case 1: return 1; // ACCEPT
+			case 2: return 2; // super-ACCEPT
 		}
 	}
 
-	return 0;
+	return 0; // DROP
 }
 
 bool Network::subscribedToMulticastGroup(const MulticastGroup &mg,bool includeBridgedGroups) const