p_nsdp=Proto("nsdp", "Netgear Switch Description Protocol")

local f_version=ProtoField.uint8("nsdp.version", "Version", base.DEC)
local f_code=ProtoField.uint8("nsdp.code", "Operation Code", base.DEC)
local f_error=ProtoField.uint8("nsdp.error", "Error Code", base.DEC)
local f_errattr=ProtoField.uint16("nsdp.errattr", "Erroneous Attribute", base.HEX)
local f_clientmac=ProtoField.ether("nsdp.clientmac", "Client MAC")
local f_switchmac=ProtoField.ether("nsdp.switchmac", "Switch MAC")
local f_seqnum=ProtoField.uint32("nsdp.seqnum", "Sequence Number", base.DEC)

p_nsdp.fields={
 f_version, f_code, f_error, f_errattr, f_clientmac, f_switchmac, f_seqnum
}





local op_codes={
 [1]="Read Request", 
 [2]="Read Reply", 
 [3]="Write Request", 
 [4]="Write Reply"
}


local error_codes={
 [0]="OK", 
 [5]="Invalid Value", 
 [7]="Invalid Password"
}


local status_codes={
 [0]="down", 
 [4]="100M", 
 [5]="1000M"
}


local bitrates_codes={
 [0]="unlimited", 
 [1]="512K", 
 [2]="1M", 
 [3]="2M", 
 [4]="4M", 
 [5]="8M", 
 [6]="16M", 
 [7]="32M", 
 [8]="64M", 
 [9]="128M", 
 [10]="256M", 
 [11]="512M"
}


local vlan_type_codes={
 [1]="port basic", 
 [2]="port advanced", 
 [3]="802.1Q basic", 
 [4]="802.1Q advanced"
}


local qos_type_codes={
 [1]="port based", 
 [2]="802.1p"
}


local prio_codes={
 [1]="high", 
 [2]="medium", 
 [3]="normal", 
 [4]="low"
}




local function dissect_port_statistics (buffer, offset, subtree)
 
 subtree:add(buffer(offset+4, 1), string.format("Port: %i", buffer(offset+4, 1):uint()))
 subtree:add(buffer(offset+4+1+8*0, 8), "Received:", tostring(buffer(offset+4+1+8*0, 8):uint64()))
 subtree:add(buffer(offset+4+1+8*1, 8), "Sent: ", tostring(buffer(offset+4+1+8*1, 8):uint64()))
 subtree:add(buffer(offset+4+1+8*5, 8), "CRC Errors:", tostring(buffer(offset+4+1+8*5, 8):uint64()))
 
end



local function dissect_port_status (buffer, offset, subtree)
 
 local st=buffer(offset+5, 1):uint()
 subtree:add(buffer(offset+4, 1), string.format("Port: %i", buffer(offset+4, 1):uint()))
 subtree:add(buffer(offset+5, 1), string.format("Status: %i (%s)", st, status_codes[st] or "unk"))
 
end



local function dissect_bitrate (buffer, offset, subtree)
 
 local sp=buffer(offset+5, 4):uint()
 subtree:add(buffer(offset+4, 1), string.format("Port: %i", buffer(offset+4, 1):uint()))
 subtree:add(buffer(offset+5, 4), string.format("Speed: %i (%s)", sp, bitrates_codes[sp] or "unk"))
 
end


local function dissect_vlan_type (buffer, offset, subtree)
 
 local vt=buffer(offset+4, 1):uint()
 subtree:add(buffer(offset+4, 1), string.format("VLAN Type: %i (%s)", vt, vlan_type_codes[vt] or "unk"))
 
end


local function parse_ports (val)
 
 local ports=""
 
 for i=8,1,-1 do
  if ( val%2==1 ) then
   ports=ports..i.." "
  end
  val=math.floor(val/2)
 end
 
 return ports
 
end


local function dissect_vlan_8021q_conf (buffer, offset, subtree)
 
 subtree:add(buffer(offset+4, 2), string.format("VLAN: %u", buffer(offset+4, 2):uint()))
 
 if ( buffer(offset+2, 2):uint()>=4 ) then
  subtree:add(buffer(offset+6, 1), "Ports:", parse_ports(buffer(offset+6, 1):uint()))
  subtree:add(buffer(offset+7, 1), "Tagged Ports:", parse_ports(buffer(offset+7, 1):uint()))
 end
 
end


local function dissect_vlan_pvid (buffer, offset, subtree)
 
 subtree:add(buffer(offset+4, 1), string.format("Port: %i", buffer(offset+4, 1):uint()))
 subtree:add(buffer(offset+5, 2), string.format("VLAN: %u", buffer(offset+5, 2):uint()))
 
end



local function dissect_mirror (buffer, offset, subtree)
 
 local op=buffer(offset+4, 1):uint()
 
 if ( op==0 ) then
  subtree:add(buffer(offset+4, 1), "Disabled")
 else
  subtree:add(buffer(offset+4, 1), "Output Port:", op)
  subtree:add(buffer(offset+6, 1), "Ports:", parse_ports(buffer(offset+6, 1):uint()))
 end
 
end



local attributes={
 [0x0001]={name="Product", dissect="string"}, 
 [0x0003]={name="Name", dissect="string"}, 
 [0x0004]={name="MAC", dissect="ether"}, 
 [0x0006]={name="IP", dissect="ipv4"}, 
 [0x0007]={name="Mask", dissect="ipv4"}, 
 [0x0008]={name="Gateway", dissect="ipv4"}, 
 [0x0009]={name="New Password", dissect="string"}, 
 [0x000A]={name="Password", dissect="string"}, 
 [0x000B]={name="DHCP", dissect="uint"}, 
 [0x000D]={name="Firmware Version", dissect="string"}, 
 [0x0013]={name="Restart", dissect="uint"}, 
 [0x0400]={name="Defaults", dissect="uint"}, 
 [0x0C00]={name="Port Status", dissect=dissect_port_status}, 
 [0x1000]={name="Port Statistics", dissect=dissect_port_statistics}, 
 [0x1400]={name="Reset Ports Statistics", dissect="uint"}, 
 [0x1800]={name="Cabletest Do", dissect=nil}, 
 [0x1C00]={name="Cabletest Result", dissect=nil}, 
 [0x2000]={name="VLAN Type", dissect=dissect_vlan_type}, 
 [0x2400]={name="VLAN Port Conf", dissect=nil}, 
 [0x2800]={name="VLAN 802.1Q Conf", dissect=dissect_vlan_8021q_conf}, 
 [0x2C00]={name="Destroy VLAN", dissect="uint"}, 
 [0x3000]={name="VLAN PVID", dissect=dissect_vlan_pvid}, 
 [0x3400]={name="QoS Type", dissect=nil}, 
 [0x3800]={name="QoS Config", dissect=nil}, 
 [0x4C00]={name="Input Bitrate", dissect=dissect_bitrate}, 
 [0x5000]={name="Output Bitrate", dissect=dissect_bitrate}, 
 [0x5400]={name="Broadcast Filtering State", dissect="uint"}, 
 [0x5800]={name="Broadcast Filtering Bitrate", dissect=dissect_bitrate}, 
 [0x5C00]={name="Mirror", dissect=dissect_mirror}, 
 [0x6000]={name="Ports Count", dissect="uint"}, 
 [0x6800]={name="IGMP Enable & VLAN", dissect=nil}, 
 [0x6C00]={name="Block Unknown IGMP Addresses", dissect="uint"}, 
 [0x7000]={name="Validate IGMPv3 Headers", dissect="uint"}, 
 [0xFFFF]={name="End", dissect=nil}
}






local function dissect_header (buffer, subtree)
 
 subtree:add(f_version, buffer(0, 1))
 
 subtree:add(f_code, buffer(1, 1)):append_text(" ("..(op_codes[buffer(1, 1):uint()] or "unknown")..")")
 
 local errcode=buffer(2, 1):uint()
 subtree:add(f_error, buffer(2, 1)):append_text(" ("..(error_codes[errcode] or "unknown")..")")
 
 -- add the erroneous attribute only if an error occurred
 if ( errcode~=0 ) then
  local atf=attributes[buffer(4, 2):uint()]
  subtree:add(f_errattr, buffer(4, 2)):append_text(" ("..(atf and atf.name or "unk")..")")
 end
 
 subtree:add(f_clientmac, buffer(8, 6))
 
 subtree:add(f_switchmac, buffer(14, 6))
 
 subtree:add(f_seqnum, buffer(20, 4))
 
 
end



local function dissect_attributes (buffer, subtree)
 
 local offset=32
 
 while ( offset<buffer:len() ) do
  
  if ( offset+4>buffer:len() ) then
   -- no room for an attribute header, it is an error
   subtree:add(buffer(offset), "Junk"):set_expert_flags(PI_MALFORMED, PI_ERROR)
   break
  end
  
  local code=buffer(offset, 2):uint()
  local len=buffer(offset+2, 2):uint()
  local atf=attributes[code]
  
  local attr=subtree:add(buffer(offset, math.min(4+len, buffer:len()-offset)), string.format("Attribute: 0x%04X (%s)", code, atf and atf.name or "unk"))
  attr:add(buffer(offset, 2), string.format("Code: 0x%04X", code))
  attr:add(buffer(offset+2, 2), string.format("Length: %u", len))
  
  if ( offset+4+len>buffer:len() ) then
   -- attribute length is bigger than remaining packet size, it is an error
   attr:append_text(" [malformed]")
   attr:set_expert_flags(PI_MALFORMED, PI_ERROR)
   break
  end
  
  
  if ( len<=0 ) then
   -- no data, display nothing
  elseif ( atf==nil or atf.dissect==nil ) then
   -- unknown attribute, display raw bytes
   attr:add(buffer(offset+4, len), "Data:", tostring(buffer(offset+4, len):bytes()))
  elseif ( type(atf.dissect)=="function" ) then
   -- custom sub-dissector for complex type
   atf.dissect(buffer, offset, attr)
  else
   -- simple type, directly show it
   local func=assert(loadstring("return function(buffer, offset, len) return tostring(buffer(offset+4, len):"..atf.dissect.."()) end"))() -- ugly, isn't it ?
   attr:add(buffer(offset+4, len), atf.name..":", func(buffer, offset, len))
  end
  
  offset=offset+4+len
  
 end
 
end



function p_nsdp.dissector (buffer, pinfo, tree)
 
 pinfo.cols.protocol=p_nsdp.name
 local subtree=tree:add(p_nsdp, buffer())
 
 -- stop if the packet is too small to be valid
 if ( buffer:len()<32 ) then return end
 
 dissect_header(buffer, subtree)
 
 -- stop if it is just a header
 if ( buffer:len()==32 ) then return end
 
 local attr_list=subtree:add(buffer(32), "Attributes list")
 dissect_attributes(buffer, attr_list)
 
end



function p_nsdp.init ()
end



local udp_dissector_table=DissectorTable.get("udp.port")
dissector=udp_dissector_table:get_dissector(63322)
udp_dissector_table:add(63322, p_nsdp)