Basic L2/L3 filter for rules engine (not integrated yet) and some cleanup.

1 files changed, 229 insertions, 0 deletions

diff --git a/node/Filter.cpp b/node/Filter.cpp
new file mode 100644
index 00000000..d0fccb9d
--- /dev/null
+++ b/node/Filter.cpp
@@ -0,0 +1,229 @@
+/*
+ * ZeroTier One - Network Virtualization Everywhere
+ * Copyright (C) 2011-2016  ZeroTier, Inc.  https://www.zerotier.com/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+
+#include "Constants.hpp"
+#include "RuntimeEnvironment.hpp"
+#include "Address.hpp"
+#include "MAC.hpp"
+#include "InetAddress.hpp"
+#include "Filter.hpp"
+
+// Returns true if packet appears valid; pos and proto will be set
+static bool _ipv6GetPayload(const uint8_t *frameData,unsigned int frameLen,unsigned int &pos,unsigned int &proto)
+{
+	if (frameLen < 40)
+		return false;
+	pos = 40;
+	proto = frameData[6];
+	while (pos <= frameLen) {
+		switch(proto) {
+			case 0: // hop-by-hop options
+			case 43: // routing
+			case 60: // destination options
+			case 135: // mobility options
+				if ((pos + 8) > frameLen)
+					return false; // invalid!
+				proto = frameData[pos];
+				pos += ((unsigned int)frameData[pos + 1] * 8) + 8;
+				break;
+
+			//case 44: // fragment -- we currently can't parse these and they are deprecated in IPv6 anyway
+			//case 50:
+			//case 51: // IPSec ESP and AH -- we have to stop here since this is encrypted stuff
+			default:
+				return true;
+		}
+	}
+	return false; // overflow == invalid
+}
+
+namespace ZeroTier {
+
+const ZT_VirtualNetworkRule *Filter::run(
+	const RuntimeEnvironment *RR,
+	const Address &ztSource,
+	const Address &ztDest,
+	const MAC &macSource,
+	const MAC &macDest,
+	const uint8_t *frameData,
+	const unsigned int frameLen,
+	const unsigned int etherType,
+	const unsigned int vlanId,
+	const ZT_VirtualNetworkRule *rules,
+	const unsigned int ruleCount)
+{
+	uint8_t thisSetMatches = 1;
+	for(unsigned int rn=0;rn<ruleCount;++rn) {
+		const ZT_VirtualNetworkRuleType rt = (ZT_VirtualNetworkRuleType)(rules[rn].t & 0x7f);
+		uint8_t thisRuleMatches = 0;
+
+		switch(rt) {
+			case ZT_NETWORK_RULE_ACTION_DROP:
+			case ZT_NETWORK_RULE_ACTION_ACCEPT:
+			case ZT_NETWORK_RULE_ACTION_TEE:
+			case ZT_NETWORK_RULE_ACTION_REDIRECT:
+				if (thisSetMatches)
+					return &(rules[rn]);
+				thisSetMatches = 1;
+				break;
+
+			case ZT_NETWORK_RULE_MATCH_SOURCE_ZEROTIER_ADDRESS:
+				thisRuleMatches = (uint8_t)(rules[rn].v.zt == ztSource.toInt());
+				break;
+			case ZT_NETWORK_RULE_MATCH_DEST_ZEROTIER_ADDRESS:
+				thisRuleMatches = (uint8_t)(rules[rn].v.zt == ztDest.toInt());
+				break;
+			case ZT_NETWORK_RULE_MATCH_VLAN_ID:
+				thisRuleMatches = (uint8_t)(rules[rn].v.vlanId == (uint16_t)vlanId);
+				break;
+			case ZT_NETWORK_RULE_MATCH_VLAN_PCP:
+				// NOT SUPPORTED YET
+				thisRuleMatches = (uint8_t)(rules[rn].v.vlanPcp == 0);
+				break;
+			case ZT_NETWORK_RULE_MATCH_VLAN_DEI:
+				// NOT SUPPORTED YET
+				thisRuleMatches = (uint8_t)(rules[rn].v.vlanDei == 0);
+				break;
+			case ZT_NETWORK_RULE_MATCH_ETHERTYPE:
+				thisRuleMatches = (uint8_t)(rules[rn].v.etherType == (uint16_t)etherType);
+				break;
+			case ZT_NETWORK_RULE_MATCH_MAC_SOURCE:
+				thisRuleMatches = (uint8_t)(MAC(rules[rn].v.mac,6) == macSource);
+				break;
+			case ZT_NETWORK_RULE_MATCH_MAC_DEST:
+				thisRuleMatches = (uint8_t)(MAC(rules[rn].v.mac,6) == macDest);
+				break;
+			case ZT_NETWORK_RULE_MATCH_IPV4_SOURCE:
+				if ((etherType == ZT_ETHERTYPE_IPV4)&&(frameLen >= 20)) {
+					thisRuleMatches = (uint8_t)(InetAddress((const void *)&(rules[rn].v.ipv4.ip),4,rules[rn].v.ipv4.mask).containsAddress(InetAddress((const void *)(frameData + 12),4,0)));
+				} else {
+					thisRuleMatches = 0;
+				}
+				break;
+			case ZT_NETWORK_RULE_MATCH_IPV4_DEST:
+				if ((etherType == ZT_ETHERTYPE_IPV4)&&(frameLen >= 20)) {
+					thisRuleMatches = (uint8_t)(InetAddress((const void *)&(rules[rn].v.ipv4.ip),4,rules[rn].v.ipv4.mask).containsAddress(InetAddress((const void *)(frameData + 16),4,0)));
+				} else {
+					thisRuleMatches = 0;
+				}
+				break;
+			case ZT_NETWORK_RULE_MATCH_IPV6_SOURCE:
+				if ((etherType == ZT_ETHERTYPE_IPV6)&&(frameLen >= 40)) {
+					thisRuleMatches = (uint8_t)(InetAddress((const void *)rules[rn].v.ipv6.ip,16,rules[rn].v.ipv6.mask).containsAddress(InetAddress((const void *)(frameData + 8),16,0)));
+				} else {
+					thisRuleMatches = 0;
+				}
+				break;
+			case ZT_NETWORK_RULE_MATCH_IPV6_DEST:
+				if ((etherType == ZT_ETHERTYPE_IPV6)&&(frameLen >= 40)) {
+					thisRuleMatches = (uint8_t)(InetAddress((const void *)rules[rn].v.ipv6.ip,16,rules[rn].v.ipv6.mask).containsAddress(InetAddress((const void *)(frameData + 24),16,0)));
+				} else {
+					thisRuleMatches = 0;
+				}
+				break;
+			case ZT_NETWORK_RULE_MATCH_IP_TOS:
+				if ((etherType == ZT_ETHERTYPE_IPV4)&&(frameLen >= 20)) {
+					thisRuleMatches = (uint8_t)(rules[rn].v.ipTos == ((frameData[1] & 0xfc) >> 2));
+				} else if ((etherType == ZT_ETHERTYPE_IPV6)&&(frameLen >= 40)) {
+					const uint8_t trafficClass = ((frameData[0] << 4) & 0xf0) | ((frameData[1] >> 4) & 0x0f);
+					thisRuleMatches = (uint8_t)(rules[rn].v.ipTos == ((trafficClass & 0xfc) >> 2));
+				} else {
+					thisRuleMatches = 0;
+				}
+				break;
+			case ZT_NETWORK_RULE_MATCH_IP_PROTOCOL:
+				if ((etherType == ZT_ETHERTYPE_IPV4)&&(frameLen >= 20)) {
+					thisRuleMatches = (uint8_t)(rules[rn].v.ipProtocol == frameData[9]);
+				} else if (etherType == ZT_ETHERTYPE_IPV6) {
+					unsigned int pos = 0,proto = 0;
+					if (_ipv6GetPayload(frameData,frameLen,pos,proto)) {
+						thisRuleMatches = (uint8_t)(rules[rn].v.ipProtocol == (uint8_t)proto);
+					} else {
+						thisRuleMatches = 0;
+					}
+				} else {
+					thisRuleMatches = 0;
+				}
+				break;
+			case ZT_NETWORK_RULE_MATCH_IP_SOURCE_PORT_RANGE:
+			case ZT_NETWORK_RULE_MATCH_IP_DEST_PORT_RANGE:
+				if ((etherType == ZT_ETHERTYPE_IPV4)&&(frameLen >= 20)) {
+					const unsigned int headerLen = 4 * (frameData[0] & 0xf);
+					int p = -1;
+					switch(frameData[9]) { // IP protocol number
+						// All these start with 16-bit source and destination port in that order
+						case 0x06: // TCP
+						case 0x11: // UDP
+						case 0x84: // SCTP
+						case 0x88: // UDPLite
+							if (frameLen > (headerLen + 4)) {
+								unsigned int pos = headerLen + (((unsigned int)(rt == ZT_NETWORK_RULE_MATCH_IP_DEST_PORT_RANGE)) << 1); // headerLen or +2 for destination port
+								p = (int)frameData[pos++] << 8;
+								p |= (int)frameData[pos];
+							}
+							break;
+					}
+					thisRuleMatches = (p > 0) ? (uint8_t)((p >= (int)rules[rn].v.port[0])&&(p <= (int)rules[rn].v.port[1])) : (uint8_t)0;
+				} else if (etherType == ZT_ETHERTYPE_IPV6) {
+					unsigned int pos = 0,proto = 0;
+					if (_ipv6GetPayload(frameData,frameLen,pos,proto)) {
+						int p = -1;
+						switch(proto) { // IP protocol number
+							// All these start with 16-bit source and destination port in that order
+							case 0x06: // TCP
+							case 0x11: // UDP
+							case 0x84: // SCTP
+							case 0x88: // UDPLite
+								if (frameLen > (pos + 4)) {
+									p = (int)frameData[pos++] << 8;
+									p |= (int)frameData[pos];
+								}
+								break;
+						}
+						thisRuleMatches = (p > 0) ? (uint8_t)((p >= (int)rules[rn].v.port[0])&&(p <= (int)rules[rn].v.port[1])) : (uint8_t)0;
+					} else {
+						thisRuleMatches = 0;
+					}
+				} else {
+					thisRuleMatches = 0;
+				}
+				break;
+			case ZT_NETWORK_RULE_MATCH_CHARACTERISTICS:
+				/*
+				if (etherType == ZT_ETHERTYPE_IPV4) {
+				} else if (etherType == ZT_ETHERTYPE_IPV6) {
+				} else {
+					thisRuleMatches = 0;
+				}
+				*/
+				break;
+			case ZT_NETWORK_RULE_MATCH_FRAME_SIZE_RANGE:
+				thisRuleMatches = (uint8_t)((frameLen >= (unsigned int)rules[rn].v.frameSize[0])&&(frameLen <= (unsigned int)rules[rn].v.frameSize[1]));
+				break;
+		}
+
+		// thisSetMatches remains true if the current rule matches... or does NOT match if not bit (0x80) is 1
+		thisSetMatches &= (thisRuleMatches ^ ((rules[rn].t >> 8) & 1));
+	}
+
+	return (const ZT_VirtualNetworkRule *)0; // no matches
+}
+
+} // namespace ZeroTier