LLDP decoding.

decode/ethernet_packet.js

@@ -2,6 +2,7 @@ var EthernetAddr = require("./ethernet_addr");
 var IPv4 = require("./ipv4");
 var IPv6 = require("./ipv6");
 var Arp = require("./arp");
+var LLDP = require("./lldp");
 var Vlan = require("./vlan");
 
 function EthernetPacket(emitter) {
@@ -46,7 +47,7 @@ EthernetPacket.prototype.decode = function (raw_packet, offset) {
             this.payload = new IPv6(this.emitter).decode(raw_packet, offset);
             break;
         case 0x88cc: // LLDP - http://en.wikipedia.org/wiki/Link_Layer_Discovery_Protocol
-            this.payload = "need to implement LLDP";
+            this.payload = new LLDP(this.emitter).decode(raw_packet, offset);
             break;
         default:
             console.log("node_pcap: EthernetFrame() - Don't know how to decode ethertype " + this.ethertype);

decode/lldp.js

@@ -0,0 +1,117 @@
+var EthernetAddr = require("./ethernet_addr");
+var IPv4Addr = require("./ipv4_addr");
+
+function LLDP(emitter) {
+    this.emitter = emitter;
+    this.chassisId = undefined;
+    this.chassisIdType = undefined;
+    this.portId = undefined;
+    this.portIdType = undefined;
+    this.ttl = undefined;
+    this.orgTLVs = [];
+    this.otherTLVs = [];
+}
+
+// http://en.wikipedia.org/wiki/Address_Resolution_Protocol
+LLDP.prototype.decode = function (raw_packet, offset) {
+    var tOffset = offset;
+
+    while(tOffset < raw_packet.length) {
+
+        // Read TLV header
+        var tlvType = raw_packet[tOffset] >> 1;
+        var tlvLength = (raw_packet.readUInt16BE(tOffset) & 0x1FF);
+
+        // Move along the packet to the TLV value
+        tOffset += 2;
+
+        // Parse value
+        switch(tlvType) {
+
+            // end of packet
+            case 0: break;
+
+            // chassis type
+            case 1: {
+                this.chassisIdType = raw_packet[tOffset];
+                switch(this.chassisIdType) {
+                    case 4: { // MAC Address
+                        this.chassisId = new EthernetAddr(raw_packet, tOffset);
+                    }; break;
+                    default: {
+                        this.chassisId = raw_packet.slice(tOffset, tOffset+tlvLength-1);
+                    }
+                }
+            } break;
+
+            // port ID
+            case 2: {
+                this.portIdType = raw_packet[tOffset];
+                switch(this.portIdType) {
+                    case 3: { // MAC Address
+                        this.portId = new EthernetAddr(raw_packet, tOffset);
+                    }; break;
+                    default: {
+                        this.portId = raw_packet.slice(tOffset, tOffset+tlvLength-1);
+                    }
+                }
+            }; break;
+
+            // TTL
+            case 3: {
+                this.ttl = raw_packet.readUInt16BE(tOffset);
+            } break;
+
+            // Port Description
+            case 4: {
+                this.portDescription = raw_packet.toString('utf8', tOffset, tOffset+tlvLength);
+            } break;
+
+            // System Description
+            case 5: {
+                this.systemName = raw_packet.toString('utf8', tOffset, tOffset+tlvLength);
+            } break;
+
+            // System Description
+            case 6: {
+                this.systemDescription = raw_packet.toString('utf8', tOffset, tOffset+tlvLength);
+            } break;
+
+
+            // System management address
+            case 8: {
+
+                // TODO: add support for more address types, OID extraction, etc.
+                if(raw_packet[tOffset+1] == 1) { // IPv4
+                    this.managementAddress = new IPv4Addr().decode(raw_packet, tOffset+2);
+                }
+
+            }
+
+            case 127: {
+                this.orgTLVs.push(raw_packet.slice(tOffset, tOffset+tlvLength-1));
+            }
+
+            /* Please add more TLV's here */
+
+            default: {
+                this.otherTLVs.push({ type: tlvType, value: raw_packet.slice(tOffset, tOffset+tlvLength) });
+            }
+        }
+
+        tOffset += tlvLength;
+    }
+
+    // Return via emitter? idk
+    if(this.emitter) { this.emitter.emit("lldp", this); }
+    return this;
+};
+
+LLDP.prototype.decoderName = "lldp";
+LLDP.prototype.eventsOnDecode = true;
+
+LLDP.prototype.toString = function () {
+    return 'LLDP Announcement from ' + this.chassisId;
+};
+
+module.exports = LLDP;