diff --git a/nselib/snmp.lua b/nselib/snmp.lua
new file mode 100644
index 000000000..07162a844
--- /dev/null
+++ b/nselib/snmp.lua
@@ -0,0 +1,464 @@
+--- SNMP functions
+--@copyright See nmaps COPYING for licence
+
+
+module(...,package.seeall)
+
+local function encodeInt(val)
+   local lsb = 0
+   if val > 0 then
+      local valStr = ""
+      while (val > 0) do
+	 lsb = math.mod(val, 256)
+	 valStr = valStr .. bin.pack("C", lsb)
+	 val = math.floor(val/256)
+      end
+      if lsb > 127 then -- two's complement collision
+	 valStr = valStr .. bin.pack("H", "00")
+      end
+
+      return string.reverse(valStr)
+   elseif val < 0 then
+      local i = 1
+      local tcval = val + 256 -- two's complement
+      while tcval <= 127 do
+	 tcval = tcval + (math.pow(256, i) * 255)
+	 i = i+1
+      end
+      local valStr = ""
+      while (tcval > 0) do
+	 lsb = math.mod(tcval, 256)
+	 valStr = valStr .. bin.pack("C", lsb)
+	 tcval = math.floor(tcval/256)
+      end
+      return string.reverse(valStr)
+   else -- val == 0
+      return bin.pack("x")
+   end
+end
+
+local function encodeLength(val)
+   if (val >= 128) then
+      local valStr = ""
+      while (val > 0) do
+	 local lsb = math.mod(val, 256)
+	 valStr = valStr .. bin.pack("C", lsb)
+	 val = math.floor(val/256)
+      end
+      return bin.pack("CA", string.len(valStr) + 0x80, string.reverse(valStr))
+      -- count down
+   else 
+      return bin.pack("C", val)
+   end
+end
+
+function encode(val)
+   local vtype = type(val)
+   if (vtype == 'number') then
+      local ival = encodeInt(val)
+      local len = encodeLength(string.len(ival))
+      return bin.pack('HAA', '02', len, ival)
+   end
+   if (vtype == 'string') then
+      local len = encodeLength(string.len(val))
+      return bin.pack('HAA', '04', len, val)
+   end
+   if (vtype == 'nil' or vtype == 'boolean') then
+      return bin.pack('H', '05 00')
+   end
+   if (vtype == 'table') then -- complex data types
+      if val._snmp == '06' then -- OID
+	 local oidStr = bin.pack("C", val[1]*40 + val[2])
+	 for i = 3, #val do
+	    oidStr = oidStr .. bin.pack("C", val[i])
+	 end 
+	 return bin.pack("HCA", '06', #val - 1, oidStr) 
+      elseif (val._snmp == '40') then -- ipAddress
+	 return bin.pack("HC4", '40 04', unpack(val))
+      elseif (val._snmp == '41') then -- counter
+	 local cnt = encodeInt(val[1])
+	 return bin.pack("HAA", val._snmp, encodeLength(string.len(cnt)), cnt)
+      elseif (val._snmp == '42') then -- gauge
+	 local gauge = encodeInt(val[1])
+	 return bin.pack("HAA", val._snmp, encodeLength(string.len(gauge)), gauge)
+      elseif (val._snmp == '43') then -- timeticks
+	 local ticks = encodeInt(val[1])
+	 return bin.pack("HAA", val._snmp, encodeLength(string.len(ticks)), ticks)
+      elseif (val._snmp == '44') then -- opaque
+	 return bin.pack("HAA", val._snmp, encodeLength(string.len(val[1])), val[1])
+      end
+      local encVal = ""
+      for _, v in ipairs(val) do
+	 encVal = encVal .. encode(v) -- todo: buffer?
+      end
+      local tableType = bin.pack("H", "30")
+      if (val["_snmp"]) then 
+	 tableType = bin.pack("H", val["_snmp"]) 
+      end
+      return bin.pack('AAA', tableType, encodeLength(string.len(encVal)), encVal)
+   end
+   return ''
+end
+
+local function decodeLength(encStr, pos)
+   local elen
+   pos, elen = bin.unpack('C', encStr, pos)
+   if (elen > 128) then
+      elen = elen - 128
+      local elenCalc = 0
+      local elenNext
+      for i = 1, elen do
+	 elenCalc = elenCalc * 256
+	 pos, elenNext = bin.unpack("C", encStr, pos)
+	 elenCalc = elenCalc + elenNext
+      end
+      elen = elenCalc
+   end
+   return pos, elen
+end
+
+local function decodeInt(encStr, len, pos)
+   local hexStr
+   pos, hexStr = bin.unpack("H" .. len, encStr, pos)
+   local value = tonumber(hexStr, 16)
+   if (value >= math.pow(256, len)/2) then
+      value = value - math.pow(256, len)
+   end
+   return pos, value
+end
+
+local function decodeSeq(encStr, len, pos)
+   local seq = {}
+   local sPos = 1
+   local i = 1
+   local sStr
+   pos, sStr = bin.unpack("A" .. len, encStr, pos)
+   while (sPos < len) do
+      sPos, newSeq = decode(sStr, sPos)
+      table.insert(seq, newSeq)
+      i = i + 1
+   end
+   return pos, seq
+end
+
+function decode(encStr, pos)
+   local etype, elen
+   pos, etype = bin.unpack("H1", encStr, pos)
+   pos, elen = decodeLength(encStr, pos)
+   if (etype == "02") then -- INTEGER
+      return decodeInt(encStr, elen, pos)
+      
+   elseif (etype == "04") then -- STRING
+      return bin.unpack("A" .. elen, encStr, pos)
+      
+   elseif (etype == "05") then -- NULL
+      return pos, false
+
+   elseif (etype == "06") then -- OID
+      local oid = {}
+      oid._snmp = '06'
+      pos, octet = bin.unpack("C", encStr, pos)
+      oid[2] = math.mod(octet, 40)
+      octet = octet - oid[2]
+      oid[1] = octet/40
+      for i = 2, elen do
+	 pos, oid[i+1] = bin.unpack("C", encStr, pos)
+      end
+      return pos, oid
+   elseif (etype == "30") then -- sequence
+      local seq
+      pos, seq = decodeSeq(encStr, elen, pos)
+      return pos, seq
+
+   elseif (etype == "A0") then -- getReq
+      local seq
+      pos, seq = decodeSeq(encStr, elen, pos)
+      seq._snmp = etype
+      return pos, seq
+
+   elseif (etype == "A1") then -- getNextReq
+      local seq
+      pos, seq = decodeSeq(encStr, elen, pos)
+      seq._snmp = etype
+      return pos, seq
+
+   elseif (etype == "A2") then -- getResponse
+      local seq
+      pos, seq = decodeSeq(encStr, elen, pos)
+      seq._snmp = etype
+      return pos, seq
+
+   elseif (etype == "A3") then -- setReq
+      local seq
+      pos, seq = decodeSeq(encStr, elen, pos)
+      seq._snmp = etype
+      return pos, seq
+   elseif (etype == "A4") then -- Trap
+      local seq
+      pos, seq = decodeSeq(encStr, elen, pos)
+      seq._snmp = etype
+      return pos, seq
+   elseif (etype == '40') then -- App: IP-Address
+      local ip = {}
+      pos, ip[1], ip[2], ip[3], ip[4] = bin.unpack("C4", encStr, pos)
+      ip._snmp = '40'
+      return pos, ip
+   elseif (etype == '41') then -- App: counter
+      local cnt = {}
+      pos, cnt[1] = decodeInt(encStr, elen, pos)
+      cnt._snmp = '41'
+      return pos, cnt
+   elseif (etype == '42') then -- App: gauge
+      local gauge = {}
+      pos, gauge[1] = decodeInt(encStr, elen, pos)
+      gauge._snmp = '42'
+      return pos, gauge
+   elseif (etype == '43') then -- App: TimeTicks
+      local ticks = {}
+      pos, ticks[1] = decodeInt(encStr, elen, pos)
+      ticks._snmp = '43'
+      return pos, ticks
+   elseif (etype == '44') then -- App: opaque
+      local opaque = {}
+      pos, opaque[1] = bin.unpack("A" .. elen, encStr, pos)
+      opaque._snmp = '44'
+      return pos, opaque
+   end
+   return pos, nil
+end
+
+function dec(encStr, pos)
+   local result
+   local _
+   _, result = decode(encStr, pos)
+   return result
+end
+
+function buildPacket(PDU, version, commStr)
+   local comm = nmap.registry.args.snmpcommunity
+   if (not comm) then comm = nmap.registry.snmpcommunity end
+   if (not comm) then comm = commStr end
+   if (not comm) then comm = "public" end
+
+   if (not version) then version = 0 end
+   local packet = {}
+   packet[1] = version
+   packet[2] = comm
+   packet[3] = PDU
+   return packet
+end
+
+function buildGetRequest(options, ...)
+   if not options then options = {} end
+
+	 if not options.reqId then options.reqId = math.mod(nmap.clock_ms(), 65000) end
+   if not options.err then options.err = 0 end
+   if not options.errIdx then options.errIdx = 0 end
+
+   local req = {}
+   req._snmp = 'A0'
+   req[1] = options.reqId
+   req[2] = options.err
+   req[3] = options.errIdx
+   
+   local payload = {}
+   for i=1, select('#', ...) do
+      payload[i] = {}
+      payload[i][1] = select(i, ...)
+      if type(payload[i][1]) == "string" then
+	 payload[i][1] = str2oid(payload[i][1])
+      end
+      payload[i][2] = false
+   end
+   req[4] = payload
+   return req
+end
+
+function buildGetNextRequest(options, ...)
+   if not options then options = {} end
+
+	 if not options.reqId then options.reqId = math.mod(nmap.clock_ms(), 65000) end
+   if not options.err then options.err = 0 end
+   if not options.errIdx then options.errIdx = 0 end
+
+   local req = {}
+   req._snmp = 'A1'
+   req[1] = options.reqId
+   req[2] = options.err
+   req[3] = options.errIdx
+   
+   local payload = {}
+   for i=1, select('#', ...) do
+      payload[i] = {}
+      payload[i][1] = select(i, ...)
+      if type(payload[i][1]) == "string" then
+	 payload[i][1] = str2oid(payload[i][1])
+      end
+      payload[i][2] = false
+   end
+   req[4] = payload
+   return req
+end
+
+function buildSetRequest(options, oid, value) -- directly uses value if value is a table
+   if not options then options = {} end
+
+	 if not options.reqId then options.reqId = math.mod(nmap.clock_ms(), 65000) end
+   if not options.err then options.err = 0 end
+   if not options.errIdx then options.errIdx = 0 end
+
+   local req = {}
+   req._snmp = 'A3'
+   req[1] = options.reqId
+   req[2] = options.err
+   req[3] = options.errIdx
+
+   if (type(value) == "table") then
+      req[4] = value
+   else 
+      local payload = {}
+      if (type(oid) == "string") then
+	 payload[1] = str2oid(oid)
+      else
+	 payload[1] = oid
+      end
+      payload[2] = value
+      req[4] = {}
+      req[4][1] = payload
+   end
+   return req
+end
+
+function buildTrap(enterpriseOid, agentIp, genTrap, specTrap, timeStamp)
+   local req = {}
+   req._snmp = 'A4'
+   if (type(enterpriseOid) == "string") then 
+      req[1] = str2oid(enterpriseOid)
+   else
+      req[1] = enterpriseOid
+   end
+   req[2] = {}
+   req[2]._snmp = '40'
+   for n in string.gmatch(agentIp, "%d+") do
+      table.insert(req[2], tonumber(n))
+   end
+   req[3] = genTrap
+   req[4] = specTrap
+
+   req[5] = {}
+   req[5]._snmp = '43'
+   req[5][1] = timeStamp
+
+   req[6] = {}
+
+   return req
+end
+
+function buildGetResponse(options, oid, value) -- directly uses value if value is a table
+   if not options then options = {} end
+
+   -- if really a response, should use reqId of request!
+   if not options.reqId then options.reqId = math.mod(nmap.clock_ms(), 65000) end
+   if not options.err then options.err = 0 end
+   if not options.errIdx then options.errIdx = 0 end
+
+   local resp = {}
+   resp._snmp = 'A2'
+   resp[1] = options.reqId
+   resp[2] = options.err
+   resp[3] = options.errIdx
+
+   if (type(value) == "table") then
+      resp[4] = value
+   else 
+
+      local payload = {}
+      if (type(oid) == "string") then
+	 payload[1] = str2oid(oid)
+      else
+	 payload[1] = oid
+      end
+      payload[2] = value
+      resp[4] = {}
+      resp[4][1] = payload
+   end
+   return resp
+end
+
+
+function str2oid(oidStr)
+   local oid = {}
+   for n in string.gmatch(oidStr, "%d+") do
+      table.insert(oid, tonumber(n))
+   end
+   oid._snmp = '06'
+   return oid
+end
+
+
+function oid2str(oid)
+   if (type(oid) ~= "table") then return 'invalid oid' end
+   return table.concat(oid, '.')
+end
+
+
+function ip2str(ip)
+   if (type(ip) ~= "table") then return 'invalid ip' end
+   return table.concat(ip, '.')
+end
+
+function str2ip(ipStr)
+   local ip = {}
+   for n in string.gmatch(ipStr, "%d+") do
+      table.insert(ip, tonumber(n))
+   end
+   ip._snmp = '40'
+   return ip
+end
+
+function fetchResponseValues(resp)
+   if (type(resp) == "string") then
+      local _, resp = decode(resp)
+   end
+
+   if (type(resp) ~= "table") then 
+      return {}
+   end
+
+   local varBind
+   if (resp._snmp and resp._snmp == 'A2') then
+      varBind = resp[4]
+   elseif (resp[3]._snmp and resp[3]._snmp == 'A2') then
+      varBind = resp[3][4]
+   end
+
+   if (varBind and type(varBind) == "table") then
+      local result = {}
+      for k, v in ipairs(varBind) do
+	 local val = v[2]
+	 if (type(v[2]) == "table") then
+	    if (v[2]._snmp == '40') then
+	       val = v[2][1] .. '.' .. v[2][2] .. '.' .. v[2][3] .. '.' .. v[2][4]
+	    elseif (v[2]._snmp == '41') then
+	       val = v[2][1]
+	    elseif (v[2]._snmp == '42') then
+	       val = v[2][1]
+	    elseif (v[2]._snmp == '43') then
+	       val = v[2][1]
+	    elseif (v[2]._snmp == '44') then
+	       val = v[2][1]
+	    end
+	 end
+	 table.insert(result, {val, oid2str(v[1]), v[1]})
+      end
+      return result
+   end
+   return {}
+end
+
+function fetchFirst(response)
+   local result = fetchResponseValues(response)
+   if type(result) == "table" and result[1] and result[1][1] then return result[1][1]
+   else return nil
+   end
+end