From 547e2294083ea34c0d4111419cd318a0833a4bce Mon Sep 17 00:00:00 2001
From: Sebastian Wagner <2000sw@gmail.com>
Date: Tue, 4 Nov 2014 22:36:41 +0100
Subject: [PATCH 1/3] - rudimentary parsing of rfc3925 Vendor-Identifying
 Vendor Options

---
 lib/parser.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/lib/parser.js b/lib/parser.js
index 281621a..acdb0f1 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -221,6 +221,25 @@ module.exports.parse = function(msg, rinfo) {
                 offset = readIp(msg, offset, p, 'subnetAddress');
                 break;
             }
+            case 125: {         // https://tools.ietf.org/html/rfc3925
+                if(p.options.dhcpMessageType != 6) {
+                    p.options.VIVendorSpecificInformation = {};
+                    var len = msg.readUInt8(offset++),
+                        vendoropts = msg.slice(offset, offset + len),
+                        vendorpointer = 0,
+                        position = 0;
+                    while (vendorpointer + 4 + 1 < vendoropts.length) {
+                        var enterprisenumber = vendoropts.readUInt32BE(vendorpointer),
+                            dataLen = vendoropts.readUInt8(vendorpointer + 4),
+                            dataEnd = vendorpointer + 4 + 1 + dataLen,
+                            vendordata = vendoropts.slice(vendorpointer + 4 + 1, dataEnd);
+                        vendorpointer = dataEnd;
+                        p.options.VIVendorSpecificInformation[enterprisenumber] = {position: position++, vendordata: vendordata};
+                    }
+                    offset+=len;
+                    break;
+                }
+            }
             default: {
                 var len = msg.readUInt8(offset++);
                 console.log('Unhandled DHCP option ' + code + '/' + len + 'b');

From 9768c85a11be8499111793a9496ce2aba099822d Mon Sep 17 00:00:00 2001
From: Sebastian Wagner <2000sw@gmail.com>
Date: Wed, 5 Nov 2014 23:46:27 +0100
Subject: [PATCH 2/3] - hint length of vendorData, prepare subOptions

---
 lib/parser.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/parser.js b/lib/parser.js
index acdb0f1..f625231 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -222,6 +222,7 @@ module.exports.parse = function(msg, rinfo) {
                 break;
             }
             case 125: {         // https://tools.ietf.org/html/rfc3925
+                // may be used in any packets where "other" options are allowed
                 if(p.options.dhcpMessageType != 6) {
                     p.options.VIVendorSpecificInformation = {};
                     var len = msg.readUInt8(offset++),
@@ -234,7 +235,12 @@ module.exports.parse = function(msg, rinfo) {
                             dataEnd = vendorpointer + 4 + 1 + dataLen,
                             vendordata = vendoropts.slice(vendorpointer + 4 + 1, dataEnd);
                         vendorpointer = dataEnd;
-                        p.options.VIVendorSpecificInformation[enterprisenumber] = {position: position++, vendordata: vendordata};
+                        // Enterprise Number SHOULD only occur once
+                        p.options.VIVendorSpecificInformation[enterprisenumber] = {
+                            position: position++,
+                            vandordatalength: dataLen,
+                            subOptions: []
+                        };
                     }
                     offset+=len;
                     break;

From 8c6bd3885a37cb22e891caf19f3ca106c3da2e56 Mon Sep 17 00:00:00 2001
From: Sebastian Wagner <2000sw@gmail.com>
Date: Wed, 5 Nov 2014 23:47:16 +0100
Subject: [PATCH 3/3] - parse encapsulated vendor-specific option-data as
 subOption

---
 lib/parser.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/lib/parser.js b/lib/parser.js
index f625231..dffe83c 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -241,6 +241,21 @@ module.exports.parse = function(msg, rinfo) {
                             vandordatalength: dataLen,
                             subOptions: []
                         };
+                        vendorDataPointer = 0;
+                        // option-data field MUST be encoded as a sequence of code/length/value fields
+                        while (vendorDataPointer + 1 < vendordata.length) {
+                            var subOptionCode = vendordata.readUInt8(vendorDataPointer),
+                                subOptionLength = vendordata.readUInt8(vendorDataPointer + 1),
+                                subOptionStart = vendorDataPointer + 1 + 1,
+                                subOptionData = vendordata.slice(subOptionStart, subOptionStart + subOptionLength);
+                            vendorDataPointer = subOptionStart + subOptionLength;
+                            // Option codes 0 and 255 have no pre-defined interpretation or format
+                            p.options.VIVendorSpecificInformation[enterprisenumber].subOptions.push({
+                                subOptionCode:   subOptionCode,
+                                subOptionLength: subOptionLength,
+                                subOptionData:   subOptionData
+                            });
+                        }
                     }
                     offset+=len;
                     break;