SNMP Toan Tap (Diep Thanh Nguyen) - Chuong 5 - Incomplete

Chng 5 Lp trnh ng dng

SNMP vi Delphi 2010

Chun b lp trnh cc phn mm SNMP

Thit k phn mm t ng cnh bo cc li trong mng : SNMP Trap Receiver.

Thit k phn mm gim st lu lng thit b : SNMP Traffic Monitor

Thit k phn mm SNMP agent cho Windows server, h tr ly cc thng tin t to.

Abstract Syntax Notation One (ASN.1)

SNMP ton tp Chng 5: Lp trnh ng dng SNMP vi Delphi 2010

D I P T H A N H N G U Y N , 2 0 1 0 T r a n g | 2

Chng ny tc gi s trnh by cch vit cc phn mm SNMP s dng ngn ng lp trnh Delphi phin bn 14 (Delphi 2010). Mc ch chng ny l trnh by tng tng bc trong vic vit cc ng dng SNMP hn l trnh by c php lp trnh SNMP trn Delphi. Trn cc ngn ng khc th ch khc nhau cc hm khi to, gi, nhn bn tin, cn v trnh t thc hin th vn ging nhau. Cc on code ca tc gi c vit mc n gin c th d dng c hiu v chuyn i, nn chng khng phi l khun mu c tc cao nht hay by li tt nht.

Source code ca ton b cc project c th download ti trang ch ca quyn ti liu ny.

Ti sao bn cn phi lp trnh SNMP ?

Nhiu thit b, ng dng c cc hng thit k mib ring, bn khng th gim st chng bng ng dng snmp thng thng. Bn c th dng phn mm ca chnh hng thit b gim st. Nhng nu bn c nhiu chng loi thit b khc nhau th bt buc bn phi dng tng phn mm ring. By gi lm th no dng mt ng dng duy nht gim st tt c chng ? Lc ny bn cn bit cch lp trnh ng dng gim st SNMP. Cng c mt s phn mm cho php gim st custom mib nhng cha hn chng p ng hon ton nhu cu ca bn.

Cc thit b gi cc event dng trap n mt trap host. nh ngha trap chun ch c mt s event rt ngho nn, do cc dng sn phm khc nhau u c nh ngha rt nhiu trap enterpriseSpecific m phi dng sn phm ca chnh hng mi c th c c. Nu bn c file mib m t event ca cc thit b, lm th no dng mt ng dng duy nht lm host nhn event v cnh bo cho tt c cc chng loi thit b ? Lc ny bn cn bit cch lp trnh ng dng SNMP Trap receiver.

Gi s bn vit mt ng dng no , ng dng ny chy trn rt nhiu server. Ngi qun tr cn gim st hiu nng ng dng ca bn trn tt c cc server m khng cn phi truy cp vo tng server ly thng tin. Bn c th thit k giao thc v phn mm gim st ring, nhng nu s dng SNMP th ngi dng c th dng cc phn mm c sn tnh nng custom mib nh Solarwinds gim st ng dng ca bn. Lc ny bn cn bit cch lp trnh ng dng SNMP Agent b sung tnh nng ny vo ng dng ca bn.

Nu bn khng phi l ngi pht trin ng dng, hoc vic dng cc phn mm gim st c sn p ng c nhu cu cng vic th bn khng cn phi c chng ny.

1. Chun b lp trnh SNMP

Delphi 2010

Delphi l ngn ng lp trnh hng i tng, c php ging vi Pascal. Mi trng lp trnh Delphi h tr thit k form dng ko th tng t nh Visual Studio. Cc i tng giao din c ng gi gi l VCL (Visual Component Library), tng t nh Controls trong C# hay Java Beans ca Java. C hng trm component trong Delphi, v chng h tr Unicode hon ton. ng dng ca Delphi vit ra l ng dng native Windows nn khng s dng .NET Framework.

Bn cn ci t Delphi 2009 hoc 2010 vit cc ng dng SNMP.

Indy Project

Indy l mt b th vin cc component h tr lp trnh mng mc application (layer 7 trong m hnh OSI), ngha l nhng g ng dng ca bn phi x l l phn data sau khi tch ht cc header ca cc giao thc lp application. Indy h tr hu ht cc giao thc ph bin nh : TCP, UDP, IPMulticast, DNS, Echo, FTP, HTTP, IMAP4, SMTP, POP3, Telnet, ICMP, Syslog, SNMP, . Bn c th vit mt web server ch vi vi dng lnh.

Indy l mt d n m ngun m c tch hp vo Delphi. M ngun Indy c vit bng Delphi bi cc tnh nguyn vin. 1

Nu khng s dng th vin Indy vit ng dng mng, bn c th s dng cc component c sn trong Delphi l TTCPServer, TTCPClient, TUDPSocket thay th. Tuy nhin lc ny bn phi t vit phn m x l d liu cc lp cao hn.

V nu khng mun dng nhng component ca Delphi na th bn c th dng cc hm Windows API trong th vin Winsock.

1 Trang ch Indy Project : http://www.indyproject.org



Patch Indy Tiburon

B Indy km theo Delphi 2010 c li trong component IdSNMP, bn cn update ln phin bn mi nht l Indy Tiburon v li, nu khng IdSNMP s hot ng sai. Indy Tiburon c th c download ti trang ch quyn ti liu ny hoc ti link gc http://indy.fulgan.com/ZIP/

Qu trnh update thc cht l xa bn Indy trong Delphi 2010 v thay th bng bn Indy Tiburon, trnh t update nh sau :

+ Gii nn bn Indy mi ra folder IndyTiburon.

+ Khi ng Delphi 2010.

+ M v bin dch package IndyTiburon\Lib\System\IndySystem140.dpk.

+ Bin dch package IndyTiburon\Lib\Core\IndyCore140.dpk.

+ Bin dch package IndyTiburon\Lib\Core\dclIndyCore140.dpk.

+ Bin dch package IndyTiburon\Lib\Protocols\IndyProtocols140.dpk.

+ Bin dch package IndyTiburon\Lib\Protocols\dclIndyProtocols140.dpk.

+ Tt Delphi.

+ Xa tt c file trong C:\Program Files\Embarcadero\RAD Studio\7.0\lib\Indy10

+ Copy tt c cc file *.dcu trong folder IndyTiburon (k c trong subfolder) sang C:\Program Files\Embarcadero\RAD Studio\7.0\lib\Indy10 (c khong 325 file).

+ Copy 5 file *.bpl trong C:\Users\Public\Documents\RAD Studio\7.0\Bpl (Win 7) hoc C:\Documents and Settings\All Users\Documents\RAD Studio\7.0\Bpl (Win XP) v ghi vo cc file trong folder C:\Program Files\Embarcadero\RAD Studio\7.0\bin.

+ Khi ng li Delphi.

Lu : phin bn Indy ti thi im vit ti liu ny l 10.5.5, l mt phin bn vn cha h tr SNMPv2c. Do cc ng dng c vit ch hot ng ng vi SNMPv1.

2. SNMP Traffic Monitor

Gii thiu

SNMP Traffic Monitor l phn mm gim st lin tc lu lng ca interface trn thit b.

Cc tnh nng demo bao gm :

+ Ly c cc thng tin m t thit b (nhm mib-2.system).

+ Ly danh sch cc interface v cho php ngi dng chn 1 interface gim st.

+ Cho php chn cc chu k ly mu khc nhau.

+ V lu lng ra biu , 2 ng lu lng in/out ring, t ng zoom biu khi lu lng tng.

Do ch l demo tp trung vo SNMP nn phn mm c cc hn ch sau :

+ Khng gim st c cng lc nhiu interface.

+ Khng ghi nh kt qu gim st, khng in c biu .

tng thc hin

ly thng tin v h thng (tn, m t, thi gian hot ng, ) ta ly tt c OID nm di .iso.org.dod.internet.mgmt.mib-2.system (.1.3.6.1.2.1.1).

Bn thn thit b khng cung cp thng tin v tc lu lng ca interface nn ta khng th ly trc tip bng SNMP. Ta phi ly tng s byte m interface nhn ti OID .iso.org.dod.internet.mgmt.mib-2.interfaces.ifTable.ifEntry.ifInOctets (.1.3.6.1.2.1.2.2.1.10) v tng s byte truyn ti ifOutOctets (.1.3.6.1.2.1.2.2.1.16). Vic ly thng tin c thc hin lin tc v tnh (gi_tr_sau gi_tr_trc)/thi_gian_gia_cc_ln_ly_mu c c tc lu lng ca interface.

khng nh hng n chng trnh chnh, phn code qut lu lng lin tc c t trong mt thread.



Thit k giao din

Ly thng tin v thit b

Sau khi nhp IP v community string, nhn nt Ly thng tin phn mm ly v cc thng tin ca thit b trong nhm mib-2.system nh name, description, contact, .

mmInfo.Clear;

SNMP.Host := edHost.Text;

SNMP.Community := edCommunity.Text;

SNMP.ReceiveTimeout := 1000; // timeout = 1000 ms

// Bc 1 : dng hm QuickSend ly cc thng tin thuc group mib-2.system

// mt s thit b khng h tr sub-id nn ta ly c 2 object sysDescr v sysDescr.0

// hm QuickSend s tr v TRUE nu ly thng tin thnh cng, FALSE nu timeout

// kt qu ly v l mt chui cha trong bin v

s := 'sysDescr : '; // sysDescr c oid l 1.3.6.1.2.1.1.1

if SNMP.QuickSend('1.3.6.1.2.1.1.1', SNMP.Community, SNMP.Host, v) or

SNMP.QuickSend('1.3.6.1.2.1.1.1.0', SNMP.Community, SNMP.Host, v) then s := s + v;

mmInfo.Lines.Add(s); // xut kt qu ra mmInfo

s := 'sysUptime : ';



mmInfo.Lines.Add(s);

s := 'sysContact : ';




s := 'sysName : ';




s := 'sysLocation : ';






Cc thng tin ly c s c xut ra mn hnh nh v d sau

Ly s lng interface ca thit b

Ly danh sch interface index

Ly thng tin ca interface

// Bc 2 : ly tng s interface ang c trn thit b

s := 'ifNumber : ';




// nu s ifNumber l rng hoc khng phi l kiu s th gn = 0

if not TryStrToInt(v, ifNumber) then ifNumber := 0;

// Bc 3 : Ln lt ly index ca cc interface entry, bng cch GetNext lin tc, bt

u t ifIndex

SNMP.Query.Host := edHost.Text;

SNMP.Query.Community := edCommunity.Text;

SNMP.Query.Port := 161;

SNMP.Query.Version := 0; // s dng SNMP v1 (0=v1; 1=v2c)

SNMP.Query.PDUType := PDUGetNextRequest;

List.Clear;

// ifIndex c OID l 1.3.6.1.2.1.2.1.1, khi GetNext s ly c ifIndex ca interface

u tin

OID := '1.3.6.1.2.1.2.1.1';

// v tng s interface ca thit b = ifNumber nn ta lp ifNumber ln

for i := 1 to ifNumber do

begin

SNMP.Query.MIBOID.Clear; // u tin xa sanh sch OID cn query

SNMP.Query.MIBOID.Add(OID); // sau thm ifIndex ca interface cn query

j := 1;

while (j



Danh sch cc interface xut ra mn hnh nh v d sau

Qut lu lng

Sau khi c danh sch cc interface index, bn click vo mt interface trong danh sch v nhn nt Bt u gim st, phn mm s to snmp query ly thng tin ifInOctets v ifOutOctets ca interface index ang chn, qut lin tc theo chu k. on code nh sau :

snmp.Query.PDUType := PDUGetRequest;

snmp.Query.MIBOID.Clear;

// ifInOctets c oid l 1.3.6.1.2.1.2.2.1.10, dng ang c chn trong List l i

tng List.Selected, caption ca dng ny chnh l interface index

snmp.Query.MIBOID.Add('1.3.6.1.2.1.2.2.1.10.' + List.Selected.Caption);

snmp.Query.MIBOID.Add('1.3.6.1.2.1.2.2.1.16.' + List.Selected.Caption);

// gi snmp query, ly 2 item ifInOctets v ifOutOctets cng lc

snmp.SendQuery;

begin

L := List.Items[i];

{ a cc oid cn ly vo query, sau thc hin 1 GetRequest ly ton b

thng tin ca 1 interface cng lc }

SNMP.Query.MIBOID.Clear;

SNMP.Query.MIBOID.Add('1.3.6.1.2.1.2.2.1.2.' + L.Caption); // ifDescr

SNMP.Query.MIBOID.Add('1.3.6.1.2.1.2.2.1.3.' + L.Caption); // ifType

SNMP.Query.MIBOID.Add('1.3.6.1.2.1.2.2.1.5.' + L.Caption); // ifSpeed

SNMP.Query.MIBOID.Add('1.3.6.1.2.1.2.2.1.6.' + L.Caption); // ifPhysAddress

SNMP.Query.MIBOID.Add('1.3.6.1.2.1.2.2.1.7.' + L.Caption); // ifAdminStatus

SNMP.Query.MIBOID.Add('1.3.6.1.2.1.2.2.1.8.' + L.Caption); // ifOperStatus

// nu fail th cho php lp li n ln th 3

j := 1;

while (j



Sau khi c thng tin tng s byte truyn v nhn theo tng chu k ly mu, bn v chng ra trn biu . Cch x l thng tin v v biu vi component TChart ca Delphi khng nm trong phm vi quyn ti liu ny, bn hy xem thm trong source code. Hnh minh ha biu v ra nh sau :

Ch : input l lu lng i vo interface, output l lu lng i ra khi interface . Nh vy, nu gim st port upstream (u ln nh cung cp dch v) th input l lu lng download, cn nu gim st port downstream th input li l lu lng upload.

3. SNMP Trap Receiver

Gii thiu

SNMP Trap receiver l phn mm c kh nng nhn v hin th cc trap version 1.

tng thc hin

+ Dng component IdSNMP ca Delphi nhn trap port 162.

+ Khi mt trap c nhn th phn mm s xem c phi version ca trap l v1 hay khng, nu l v1 th bn tin trap s c tip tc x l.

+ Bn tin trap s c hin th ra mn hnh vi y cc thuc tnh. Chng 4 trnh by cu trc ca mt bn tin trap v1, gm : enterprise, agent-addr, generic-trap, specific-trap, time-stamp v cc variable-bindings.

+ Nu trap c kiu generic th phn mm s hin th tn trap. Chng 1 lit k 7 gi tr generic gm : coldStart(0), warmStart(1), linkDown(2), linkUp(3), authenticationFailure(4), egpNeighborloss(5),

enterpriseSpecific(6).

+ Trong cc oid c trong bn tin trap, nu oid no l con ca mib-2.system v mib-2.interfaces th n s c hin th tn thay v oid.

Thit k giao din

+ Nt [Start] bt u nhn v x l trap.

+ Checkbox [Nhn trap enterpriseSpecific] l ty chn c hin th cc trap c generic = 6 hay khng.



Cu trc d liu

c th hin th tn ca cc trap generic - v d hin th Generic : linkDown(2) thay v Generic : 2 th ta cn mt mng nh ngha chng.

c th hin th tn ca cc oid v d hin th sysDescr thay v .1.3.6.1.2.1.1.1 ta cn khi to th tc nh ngha chng

Nhn trap

Khi click nt [Start], chng trnh s thc hin vng lp lin tc nhn trap

var

genTrap: array[0..6] of string = (

'coldStart(0)', 'warmStart(1)', 'linkDown(2)', 'linkUp(3)',

authenticationFailure(4)',

'egpNeighborloss(5)', 'enterpriseSpecific(6)');

var

oid: TstringList;

procedure TfrmMain.InitCommonOID;

begin

oid := TStringList.Create;

oid.Delimiter := '=';

oid.Add('1.3.6.1.2.1.1.1=sysDescr');

oid.Add('1.3.6.1.2.1.1.2=sysObjectID');

oid.Add('1.3.6.1.2.1.1.3=sysUptime');

oid.Add('1.3.6.1.2.1.1.4=sysContact');

oid.Add('1.3.6.1.2.1.1.5=sysName');

oid.Add('1.3.6.1.2.1.1.6=sysLocation');

oid.Add('1.3.6.1.2.1.1.7=sysServices');

oid.Add('1.3.6.1.2.1.2.1=ifNumber');

oid.Add('1.3.6.1.2.1.2.2.1.1=ifIndex');

oid.Add('1.3.6.1.2.1.2.2.1.2=ifDescr');

oid.Add('1.3.6.1.2.1.2.2.1.3=ifType');

oid.Add('1.3.6.1.2.1.2.2.1.4=ifMtu');

oid.Add('1.3.6.1.2.1.2.2.1.5=ifSpeed');

oid.Add('1.3.6.1.2.1.2.2.1.6=ifPhysAddress');

oid.Add('1.3.6.1.2.1.2.2.1.7=ifAdminStatus');

oid.Add('1.3.6.1.2.1.2.2.1.8=ifOperStatus');

oid.Add('1.3.6.1.2.1.2.2.1.9=ifLastChange');

oid.Add('1.3.6.1.2.1.2.2.1.10=ifInOctets');

oid.Add('1.3.6.1.2.1.2.2.1.11=ifInUcastPkts');

oid.Add('1.3.6.1.2.1.2.2.1.12=ifInNUcastPkts');

oid.Add('1.3.6.1.2.1.2.2.1.13=ifInDiscards');

oid.Add('1.3.6.1.2.1.2.2.1.14=ifInErrors');

oid.Add('1.3.6.1.2.1.2.2.1.15=ifInUknownProtos');

oid.Add('1.3.6.1.2.1.2.2.1.16=ifOutOctets');

oid.Add('1.3.6.1.2.1.2.2.1.17=ifOutUcastPkts');

oid.Add('1.3.6.1.2.1.2.2.1.18=ifOutNUcastPkts');

oid.Add('1.3.6.1.2.1.2.2.1.19=ifOutDiscards');

oid.Add('1.3.6.1.2.1.2.2.1.20=ifOutErrors');

oid.Add('1.3.6.1.2.1.2.2.1.21=ifOutQLen');

oid.Add('1.3.6.1.2.1.2.2.1.22=ifSpecific');

end;



Hm x l trap v1 nh sau

4. SNMP Agent

5. Abstract Syntax Notation One (ASN.1)

procedure TfrmMain.bbtStartClick(Sender: TObject);

begin

snmp.ReceiveTimeout := 100; // thi gian timeout cho hm ReceiveTrap l 100ms

snmp.Active := True;

bbtStart.Enabled := False;

bbtStop.Enabled := not bbtStart.Enabled;

while snmp.Active do

begin

while snmp.ReceiveTrap = 1 do // =1 nu nhn c trap trong vng 100ms

if (ckTrapv1.Checked and (snmp.Trap.Version = 0)) then

begin

ProcessTrapv1(snmp.Trap); // hm x l bn tin trap v1

end;

Sleep(1); // nu khng tm dng 1ms th vng lp s chim 100% CPU

Application.ProcessMessages;

end;

end;

procedure TfrmMain.ProcessTrapv1(var trap: TSNMPInfo);

var i,j: integer; s: string;

begin

// nu nhn bn tin trap c generic = 6 (enterpriseSpecific) m checkbox [Nhn trap

enterpriseSpecific] khng c chn th ngng x l

if (not ckSpecific.Checked) and (Trap.GenTrap = 6) then Exit;

mm.Lines.Add('+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+');

mm.Lines.Add( 'Host: ' + Trap.Host + TAB +

'Version: ' + GetTrapVersionStr(Trap.Version) + TAB +

'Enterprise: ' + trap.Enterprise);

mm.Lines.Add( 'Generic: ' + genTrap[Trap.GenTrap] + TAB +

'Specific: ' + InttoStr(Trap.SpecTrap) + TAB +

'TimeStamp: ' + InttoStr(Trap.TimeTicks));

// nu bn tin trap c cha variable-bindings (cc cp oid-value) th ValueCount l

tng s cc oid-value cha trong trap

if Trap.ValueCount = 0 then mm.Lines.Add('(no values)')

else

for i := 0 to Trap.ValueCount - 1 do

begin

// nu oid l mt trong cc oid nm di mib-2.system v mib-2.interfaces th hin

th tn ca oid

j := isCommonOID(Trap.ValueOID[i]);

if j > -1 then s := Replacestr(Trap.ValueOID[i], oid.Names[j],

oid.ValueFromIndex[j])

else s := Trap.ValueOID[i];

mm.Lines.Add(' ' + s + TAB + '=' + TAB + Trap.Value[i]);

end;

mm.Lines.Add('');

Trap.Clear;

end;



Basic Encoding Rules

c mt bn tin SNMP

Tm tt

+