如下腳本,模擬windows和linux上的snmp-agent,返回數據給snmp請求者。
直接上代碼吧:
# -*- coding: utf-8 -*- import binascii, struct import socket import time from threading import Thread ''' windows OID 1.3.6.1.2.1.25.2.3.1.6.1 [ObjectIdentifier] //硬盤 1.3.6.1.2.1.25.2.3.1.6.2 [ObjectIdentifier] //硬盤 1.3.6.1.2.1.25.2.3.1.6.3 [ObjectIdentifier] //硬盤 1.3.6.1.2.1.25.2.3.1.6.4 [ObjectIdentifier] //硬盤 1.3.6.1.2.1.25.2.3.1.6.5 [ObjectIdentifier] //光盤 1.3.6.1.2.1.25.2.3.1.6.6 [ObjectIdentifier] //光盤 1.3.6.1.2.1.25.2.3.1.6.7 [ObjectIdentifier] //虛擬內存 1.3.6.1.2.1.25.2.3.1.6.8 [ObjectIdentifier] //物理內存 OID號不固定,當只有一塊硬盤,一個光驅時,物理內存佔用OID爲1.2.5(2.1佔用一般0,不是真實硬盤,不知道是什麼意思,真正硬盤佔用從2.2開始) ''' #a 是一個真實的請求內容,def test_parse()函數可以將他解析出來,並打印出密碼,請求類型,請求ID,OID對象 a = '''0x30, 0x82, 0x01, 0x09, 0x02, 0x01, 0x01, 0x04, 0x06, 0x70, 0x75, 0x62, 0x6c, 0x69, 0x63, 0xa0, 0x81, 0xfb, 0x02, 0x04, 0x4a, 0xbb, 0x2b, 0xac, 0x02, 0x01, 0x00, 0x02, 0x01, 0x00, 0x30, 0x81, 0xec, 0x30, 0x0d, 0x06, 0x09, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x02, 0x00, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x03, 0x03, 0x01, 0x02, 0x01, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x05, 0x01, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x05, 0x02, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x05, 0x03, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x05, 0x04, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x06, 0x01, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x06, 0x02, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x06, 0x03, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x06, 0x04, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x06, 0x05, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x06, 0x06, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x06, 0x07, 0x05, 0x00, 0x30, 0x0f, 0x06, 0x0b, 0x2b, 0x06, 0x01, 0x02, 0x01, 0x19, 0x02, 0x03, 0x01, 0x06, 0x08, 0x05, 0x00''' class snmpReqParse: struct_type = {0x02:'INTEGER_TYPE', 0x30:'SQUENCE_TYPE', 0x04:'OCTET_TYPE', 0X05:'NULL_TYPE', 0x06:'OBJID_TYPE', 0xa0:'GET_REQ_TYPE', 0xa5:'GET_BULKREQ_TYPE', 0Xa2:'RESPONSE_TYPE'} def __init__(self, request): self.request = request self.objidList = [] self.requestID = None self.getReqType = 0xa0 self.publicPasswd = '' self.parse() def parse(self): currentPos = self.parse_header1() if not currentPos: print "parse SNMP header failed!" return currentPos = self.parse_header2(currentPos) if not currentPos: print "parse SNMP header failed!" return self.parse_obj(currentPos) def parse_obj(self, pos): #開始解析obj對象了 currentPos = pos stype = struct.unpack('B', self.request[currentPos:currentPos+1])[0] currentPos += 1 currentPos = self.struct_parse(currentPos)[0] while len(self.request[currentPos:]) != 0: stype = struct.unpack('B', self.request[currentPos:currentPos+1])[0] currentPos += 1 currentPos = self.struct_parse(currentPos)[0] stype = struct.unpack('B', self.request[currentPos:currentPos+1])[0] if stype != 0x06: print "wrong type coding, must be 0x06" break currentPos += 1 currentPos, stringLen = self.struct_parse(currentPos) objid = struct.unpack(stringLen*'B', self.request[currentPos:currentPos+stringLen]) objid1stStr = str(divmod(objid[0], 40)[0]) + '.' + str(divmod(objid[0], 40)[1]) #當obj中每一段中有值大於127時,則後面一個數應該和前面一個數拼起來,例如0x8F和0X65,應該是0x8F*128+65 templist = [] temp1 = 0 for i in objid[1:]: if not temp1: if i<=127: templist.append(str(i)) else: temp1 = i else: templist.append(str((temp1-128)*128+i)) temp1 = 0 objidStr = objid1stStr + '.' + '.'.join(templist) self.objidList.append(objidStr) currentPos = currentPos+stringLen #跳過null type currentPos += 2 #print self.objidList def parse_header2(self, pos): #從團體屬性密鑰結束後,解析到OBject開始 currentPos = pos stype = struct.unpack('B', self.request[currentPos:currentPos+1])[0] self.getReqType = stype currentPos += 1 currentPos = self.struct_parse(currentPos)[0] stype = struct.unpack('B', self.request[currentPos:currentPos+1])[0] if stype == 0x02: startPos = currentPos + 1 currentPos, stringLen = self.struct_parse(startPos) self.requestID = self.request[currentPos:currentPos+stringLen] currentPos += stringLen #直接跳過error-statues和error-index currentPos += 6 return currentPos else: print 'wrong type coding ,should be 0x02!' return def parse_header1(self): #start parse,從開始到得到團體屬性密鑰 #currentPos爲讀取數據流的位置 stype = struct.unpack('B', self.request[0:1])[0] if stype == 0x30: currentPos = self.struct_parse(1)[0] stype = struct.unpack('B', self.request[currentPos:currentPos+1])[0] if stype == 0x02: startPos = currentPos+1 currentPos = self.struct_parse(startPos)[0] if currentPos - startPos == 1: #不做判斷了,直接跳到解析團體關鍵字 startPos = currentPos + 2 currentPos, stringLen = self.struct_parse(startPos) self.publicPasswd = self.request[startPos+1:startPos+stringLen+1] currentPos = startPos+stringLen+1 return currentPos else: print "wrong SNMP version ,must be v2c!" else: print "wrong type coding: %s,should be 0x02"%stype else: print "wrong type coding: %s, should be 0x30 "%stype def struct_parse(self, startpos): #結構解析,startpos的位置已經是長度字段了,解析出來,最後返回這個結構結尾的pos length = struct.unpack('B', self.request[startpos:startpos+1])[0] if length == 0x81: endpos = startpos + 2 slen = struct.unpack('B', self.request[startpos+1:endpos])[0] elif length == 0x82: endpos = startpos + 3 slen = struct.unpack('!H', self.request[startpos+1:endpos])[0] elif length <= 127: endpos = startpos + 1 slen = length else: print "wrong length coding: "%length return if len(self.request[endpos:]) < slen: print "string is not enough long!" return return endpos, slen class snmpResponse: OID = {'windows':['1.3.6.1.2.1.25.2.2.0', #內存總大小(mem_count),integar類型 '1.3.6.1.2.1.25.3.3.1.2.1', #CPU,integar類型 '1.3.6.1.2.1.25.2.3.1.5.1', #值爲0,integar類型 '1.3.6.1.2.1.25.2.3.1.5.2', #硬盤總大小,*4096單位爲字節數,integar類型 '1.3.6.1.2.1.25.2.3.1.5.3', #光驅總大小,實際爲光盤容量,沒有光盤時爲0,integar類型 '1.3.6.1.2.1.25.2.3.1.5.4', #暫時不清楚是什麼,默認我給它賦值0x009a5f,integar類型 '1.3.6.1.2.1.25.2.3.1.6.1', #值爲0,integar類型 '1.3.6.1.2.1.25.2.3.1.6.2', #硬盤佔用的大小,integar類型 '1.3.6.1.2.1.25.2.3.1.6.3', #光驅大小,和5.3一致 '1.3.6.1.2.1.25.2.3.1.6.4', #虛擬內存大小,一般不關注,integar類型 '1.3.6.1.2.1.25.2.3.1.6.5'], #物理內存使用大小(mem_use),integar類型 #內存使用率計算方法:(mem_use*65535)/(mem_count*1024) 'linux':['1.3.6.1.4.1.2021.11.11.0', #CPU剩餘,如40 '1.3.6.1.4.1.2021.4.5.0', #內存總大小,integar類型 '1.3.6.1.4.1.2021.4.6.0', #內存剩餘大小,integar類型 '1.3.6.1.4.1.2021.9.1.9.1']} #硬盤使用百分比,如60, integar類型 def __init__(self): self.getReqType = 0x00 self.reqPublicPasswd = '' self.reqObjList = [] self.OIDdic = {} self.getResType = 0xa2 self.respondID = 0 self.error_index = 0 self.error_status = 0 self.simDev = { 'publicPasswd':'public', 'platform':'windows', 'CPULOAD':45, 'totalMem':1024000, 'usedMem':102400, #mem單位爲kB 'totalDisk':512000000, 'usedDisk':100000000} def check_request(self): if self.getReqType != 0xa0: print "this tool can only support get-request" return if self.reqObjList: if self.reqObjList[0] in self.OID['windows']: self.simDev['platform'] = 'windows' for i in range(0, len(self.reqObjList)): if self.reqObjList[i] not in self.OID['windows']: self.error_index = i + 1 self.error_status = 0x02 return useMemVal = (self.simDev['usedMem']*1024)/65535 self.OIDdic = {'1.3.6.1.2.1.25.2.2.0':self.simDev['totalMem'], #內存總大小(mem_count),integar類型 '1.3.6.1.2.1.25.3.3.1.2.1':self.simDev['CPULOAD'], #CPU,integar類型 '1.3.6.1.2.1.25.2.3.1.5.1':0, #值爲0,integar類型 '1.3.6.1.2.1.25.2.3.1.5.2':self.simDev['totalDisk']/2048, #硬盤總大小,*4096單位爲字節數,integar類型 '1.3.6.1.2.1.25.2.3.1.5.3':0, #光驅總大小,實際爲光盤容量,沒有光盤時爲0,integar類型 '1.3.6.1.2.1.25.2.3.1.5.4':39519, #暫時不清楚是什麼,默認我給它賦值0x009a5f,integar類型 '1.3.6.1.2.1.25.2.3.1.6.1':0, #值爲0,integar類型 '1.3.6.1.2.1.25.2.3.1.6.2':self.simDev['usedDisk']/2048, #硬盤佔用的大小,integar類型 '1.3.6.1.2.1.25.2.3.1.6.3':0, #光驅大小,和5.3一致 '1.3.6.1.2.1.25.2.3.1.6.4':10835, #虛擬內存大小,一般不關注,integar類型 '1.3.6.1.2.1.25.2.3.1.6.5':useMemVal} elif self.reqObjList[0] in self.OID['linux']: self.simDev['platform'] = 'linux' for i in self.reqObjList: if i not in self.OID['linux']: print 'can not support the OID:', i return freeCPU = 100 - self.simDev['CPULOAD'] usedDisk = (self.simDev['usedDisk']*100)/self.simDev['totalDisk'] freeMemVal = self.simDev['totalMem'] - self.simDev['usedMem'] self.OIDdic = {'1.3.6.1.4.1.2021.11.11.0':freeCPU, #CPU剩餘 '1.3.6.1.4.1.2021.4.5.0':self.simDev['totalMem'], #內存總大小,integar類型 '1.3.6.1.4.1.2021.4.6.0':freeMemVal, #內存剩餘大小,integar類型 '1.3.6.1.4.1.2021.9.1.9.1':usedDisk} #硬盤使用百分比,如60, integar類型 else: print "the objlist will not be supported!" return else: print "error: objlist is Null!" return def build_objbuff(self): objbuff = '' if self.error_index: for i in self.reqObjList: objbuff += self.coding_obj_and_value(i) else: for i in self.reqObjList: objbuff += self.coding_obj_and_value(i, self.OIDdic[i]) if not objbuff: return objbuff = '\x30' + self.coding_of_length(len(objbuff)) + objbuff return objbuff def build_snmpbuff(self): self.check_request() objBuff = self.build_objbuff() if not objBuff: return snmpbuff = '' if self.simDev['publicPasswd'] != self.reqPublicPasswd: print "public keyword is wrong!" return else: snmpbuff = '\x02' + struct.pack('B', len(self.respondID)) + self.respondID \ + '\x02\x01' + struct.pack('B', self.error_status) \ + '\x02\x01' + struct.pack('B', self.error_index) snmpbuff += objBuff snmpbuff = '\xa2' + self.coding_of_length(len(snmpbuff)) + snmpbuff snmpbuff = '\x02\x01\x01\x04' + struct.pack('B', len(self.simDev['publicPasswd'])) + self.simDev['publicPasswd'] + snmpbuff snmpbuff = '\x30' + self.coding_of_length(len(snmpbuff)) + snmpbuff return snmpbuff def coding_obj_and_value(self, obj, val=None): temps = '' temps += self.coding_obj(obj) temps = struct.pack('2B', 0x06, len(temps)) + temps if val == None: temps += '\x05\x00' elif str(type(val)) == '<type \'str\'>': temps += '\x04' + struct.pack('B', len(val)) + val elif str(type(val)) in ['<type \'int\'>', '<type \'long\'>']: if val<=2**7: temps += '\x02\x01' + struct.pack('B', val) elif 2**7<val<=2**15: temps += '\x02\x02' + struct.pack('!H', val) elif 2**15<val<=2**23: temps += '\x02\x03' + struct.pack('!I', val)[1:] elif 2**23<val<=2**31: temps += '\x02\x04' + struct.pack('!I', val) else: print "value is too big!" return temps = '\x30' + struct.pack('B', len(temps)) + temps return temps def coding_of_length(self, slen): #SNMP中域長度的編碼方式。此函數直接返回長度字段的編碼結果 if slen<=127: return struct.pack('B', slen) if 127<slen<256: return struct.pack('2B', 0x81, slen) if 256<=slen<256**2: return struct.pack('!BH', 0x82, slen) def coding_obj(self, obj): #將1.3.6.X的OID打包成字節流 objlist = obj.split('.') objtemplist = [] objfir1byte = int(objlist[0])*40 + int(objlist[1]) objtemplist.append(struct.pack('B', objfir1byte)) for i in objlist[2:]: if int(i)>127: a, b = divmod(int(i), 128) objtemplist.append(struct.pack('2B', a+128, b)) else: objtemplist.append(struct.pack('B', int(i))) return ''.join(objtemplist) def SNMP_server(serverIP = '', passWd = 'public', SNMPPORT = 161): usock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) usock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) usock.bind((serverIP, SNMPPORT)) while 1: message, clientaddr = usock.recvfrom(8192) req = snmpReqParse(message) res = snmpResponse() res.reqPublicPasswd = req.publicPasswd res.simDev = read_config()[serverIP] res.getReqType = req.getReqType res.respondID = req.requestID res.reqObjList = req.objidList resbuff = res.build_snmpbuff() if resbuff: usock.sendto(resbuff, clientaddr) memUsage = res.simDev['usedMem']*100/res.simDev['totalMem'] diskUsage = res.simDev['usedDisk']*100/res.simDev['totalDisk'] if not res.error_index: print '########### %s ###########\n\ <%s>\n\ >>you request oid are %s\n\ >>server CPU load percentage is : %s\n\ >>server mem used percentage is : %s\n\ >>server disk used percentage is: %s'%(serverIP, time.ctime(), res.reqObjList, res.simDev['CPULOAD'], memUsage, diskUsage) def test_parse(): global a b = a.replace(', 0x', r'\x') c = '\\' + b.replace(', \n0x', r'\x')[1:] d = c.replace(r'\x', '') request = binascii.a2b_hex(d) test = snmpReqParse(request) print test.simDev('publicPasswd') print hex(test.getReqType) print test.requestID for i in test.objidList: print i def test_response(): global a b = a.replace(', 0x', r'\x') c = '\\' + b.replace(', \n0x', r'\x')[1:] d = c.replace(r'\x', '') request = binascii.a2b_hex(d) test = snmpReqParse(request) res = snmpResponse('public') res.reqPublicPasswd = test.simDev('publicPasswd') res.getReqType = test.getReqType res.respondID = test.requestID res.reqObjList = test.objidList resbuff = res.build_snmpbuff() print repr(resbuff) def read_config(): import ConfigParser cf = ConfigParser.ConfigParser() cf.read('snmpServer.ini') simSers = {} for sec in cf.sections(): simSers[sec] = {'publicPasswd':cf.get(sec, 'password'), 'CPULOAD': cf.getint(sec, 'cpuload'), 'totalMem':cf.getint(sec, 'totalMem'), 'usedMem':cf.getint(sec, 'usedMem'), 'totalDisk':cf.getint(sec, 'totalDisk'), 'usedDisk':cf.getint(sec, 'usedDisk')} return simSers def main(): sersDic = read_config() for s in sersDic.keys(): print repr(s), 'is listening!' t = Thread(target=SNMP_server, args=(s, )) t.start() time.sleep(1) if __name__=='__main__': #test_parse() #test_response() #serverIP = '172.16.1.102' #SNMP_server(serverIP) print 'start' main() raw_input('')
以上服務啓動依賴配置文件,配置文件中指定模擬的linux或者windows服務器,可以填寫多組,文件存爲snmpServer.ini
[192.168.10.102]
password = public
cpuload = 11
totalMem = 1024000
usedMem = 102400
totalDisk = 512000000
usedDisk = 100000000
[172.16.1.102]
password = public
cpuload = 30
totalMem = 1024000
usedMem = 204800
totalDisk = 512000000
usedDisk = 300000000