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LP TRNH MNG(Network programming)

1

Ging vin: Ths. Trn c Tt Khoa CNTT

Email: [email protected]

Website: www.oktot.com

Facebook: https://www.facebook.com/oktotcom/

TRNG I HC CNG NGHIP THC PHM TP.HCM

Chng 1: Nhng vn c bn ca lp trnh mng

mailto:[email protected]://www.oktot.com/https://www.facebook.com/oktotcom/

MN HC: LP TRNH MNG

2


Chng 2: Lp trnh SOCKET hng kt ni

Chng 3: Lp trnh SOCKET phi kt ni

Chng 4: S dng cc lp tr giup ca C# SOCKET

Chng 5: Lp trinh a lung (MULTI-THREADING)


3

CHNG 1: NHNG VN C BN CA LP TRNH MNG

C bn v mng my tnh

M hinh truyn thng

Cc m hnh tham chiu

Tng quan v lp trinh mng


4

Mc ch: Gii thiu cc khi nim c bn v

Mng my tnh, truyn thng mng my tnh

M hinh OSI, TCP/IP

Windows Socket

Lp trnh Socket trong C#

Cc lp DNS trong C#

Yu cu: Sinh vin nm vng cc khi nim c bn v

Lp trnh mng

S dng socket trong lp trnh mng

MC CH YU CU


5


C bn v mng my tnh

M hinh truyn thng

Cc m hnh tham chiu



6

C bn v mng my tnh


C bn v mng my tnh

7

Khi nim mng my tnh

Tp hp cc my tnh v thit b mng kt ni vi nhau theo mt kin

trc no trao i d liu

My tnh: my trm, my ch,

b nh tuyn, switch..

Kt ni bng phng tin truyn thng

Theo mt kin trc no

Cc dng my tnh ?


8

C bn v mng my tnh

Internet ngy nay


9

C bn v mng my tnh

X l tp trung hay phn tn


10

C bn v mng my tnh

Kin trc mng: Hnh trng (topology) v giao thc (protocol)


Thc t l s kt hp ca nhiu hnh trng

Trc (Bus) Vng (Ring) Sao (Star)

11

C bn v mng my tnh

Giao thc l g?


12

C bn v mng my tnh

Giao thc mng

Chng 1: Nhng vn c bn ca lp trnh mng 20

Protocol: Quy tc truyn thng

Gi: Mt thng ip vi yu cu hoc thng tin

Nhn: Nhn mt thng ip vi thng tin, s kin hoc hnh ng

nh ngha khun dng v th t truyn, nhn thng ipgia cc thc th trn mng hoc cc hnh ng tng ngkhi nhn thng ip

V d v giao thc mng: TCP, UDP, IP, HTTP,Telnet, SSH, Ethernet,

13


C bn v mng my tnh

M hinh truyn thng

Cc m hnh tham chiu



M hnh truyn thng

Chuyn mch knh

Trao i d liu s dng mt knh ring

Mi lin kt s dng mt knh. Ti nguyn ca knh khng c s bi knh

khc cho n khi ng lin kt

Ti nguyn c gn ring cho mi knh, k c khi ti nguyn ang ri, ngi

khc cng khng s dng c

M hnh truyn thng

Chuyn mch gi

D liu c chia thnh cc gi(packets) v c truyn qua mng

Nhiu lin kt c th chia s mt knh

Internet (Vi giao thc IP) s dng chuyn mch gi

Ton b bng thng c chia s cho tt c mi ngi

Nu cn bng thng th ai cng c th s dng c

16

M hnh truyn thng

So snh


Chuyn mch knhMi knh ch s dng mt lin kt

Bo m bng thng (cn cho cc ng dng audio/video)

Lng ph nu lin kt khng s dng ht kh nng ca knh

Chuyn mch giTng hiu qu s dng bng thng

Tt cho cc d liu n ngu nhin, khng nh trc

Hn ch: Tc ngh lm tr v mt gi tin, khng m bo bng thng

17

M hnh truyn thng

Truyn thng hng lin kt v khng hng lin kt

Truyn thng hng lin kt

D liu c truyn qua mt lin kt c thit lp

Thng qua 3 giai on: Thit lp lin kt, truyn d liu hy b lin

kt.

ng tin cy

Truyn thng khng hng lin kt

Khng thit lp lin kt, ch c giai on truyn d liu

Khng tin cy - Best effort


18


C bn v mng my tnh

M hinh truyn thng

Cc m hnh tham chiu



19

Cc m hnh tham chiu

OSI - Open System Interconnection: Bao gm 7 tng


20

Cc m hnh tham chiu

Chc nng chung ca cc tng

Vt l: Truyn bits trn ng truyn

Lin kt d liu: Truyn d liu gia cc thnh phn ni kt trong mng

Mng: chn ng, chuyn tip gi tin t ngun ti ch

Giao vn: X l vic truyn-nhn d liu cho cc ng dng

Phin: ng b ha, check-point, khi phc qu trnh trao i

Trnh din: cho php cc ng dng biu din d liu, e.g., m ha, nn,

chuyn i

ng dng: H tr cc ng dng trn mng


21

Cc m hnh tham chiu

M hnh OSI v TCP/IP

Trong m hnh TCP/IP (Internet), chc nng 3 tng trn c phn nh

vo mt tng duy nht


Ethernet/10M

CAT5

IP

FTP

TCP

IP

100M/Ethernet

CAT5

IP

FTP

TCP

Ngun chNt trung gian

100M

CAT5

10M

CAT5

V d v qu trnh gi d liu t ngun, qua nt trung gian (b inh tuyn), ri ti ch


M hnh phn tng ca Internet

a ch

Gi qu

Trang tr

Dn a ch

a ch


ng gi d liu (Encapsulation)

(N+1) PDU

(N) PDU

(N-1) PDU

HN

HN HN-1

Layer (N+1)

Layer (N-1)

Layer (N)

Service interface

Protocol N

Service interface

Protocol N-1

addr.


PDU: Protocol Data Unit n v d liu giao thc

Data Data

ExHTTP header

TCP header

IP header

Ethernet Frame

Signal

Application

TCP

IP

Network Interface

Physical

Sender

Bn gi

Mi tng thm cc thng tin iu khin (header) vo gi tin v truyn xung tngdi

Bn nhn

Mi tng x l thng tin da trn phn header, sau b header v truyn d liu ln

tng trn

Physical

Receiver

Application

TCP

IP

Network Interface

H giao thc TCP/IP v qu trnh ng gi

CAT5

End node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

Intermediate node

D

End node

liu - payload


Protocol stack v qu trnh ng gi

CAT5

End node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

Intermediate node

TCP header

End node

D liu - payload



CAT5

End node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

Intermediate node

IP header TCP header

End node

D liu - payload


CAT5

End node End nodeIntermediate node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

D liu - payloadEthernet header IP header TCP header



CAT5

End node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

Intermediate node


End node

D liu - payload



CAT5CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

Intermediate node


End node

D liu - payload

End node

WDM header



CAT5

End node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

Intermediate node


End node

D liu - payload



CAT5

End node End nodeIntermediate node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

D liu - payloadEthernet header IP header TCP header



CAT5

End node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

Intermediate node


End node

D liu - payload



CAT5

End node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

Intermediate node

TCP header

End node

D liu - payload



CAT5

End node Intermediate node

CAT5

Ethernet/10M

IP

FTP

TCP

Ethernet/100M

IP

FTP

TCP

10M

IP

10G

CAT5 WDM

10G

IP

WDM CAT5

End node

D liu - payload




Tm tt: u im ca kin trc phn tng

Chia nh cho php d dng xc nh chc nng ca mi tng

Cc tng hot ng c lp

Tng trn ch quan tm n vic s dng tng di m khng quan tm

n cc tng xa hn.

Cho php nh ngha giao din chung gia cc tng

Kh nng m rng

Mm do, linh hot vi cc cng ngh mi

Trao i gia cc tng ng mc: C th ci tin h thng bng cch thay

i cng ngh ca tng tng ng. Vd: ISDNADSLFTTHIPv4IPv6

Nu khng phn tng: Khi mun thay i, phi lm ton b

application

TCP/UDP

IP

data linke.g. 00:11:24:79:8e:82

physical

Port Number, e.g. Port 80

IP address, e.g. 203.12.15.165

Physical address / MAC address


nh danh trn Internet v quan h vi cc tng

a ch vt l /a ch MAC

S dng trong tng lin kt d liu

C nh trn card mng NIC ( Network Interface Card)

S dng a ch ha my tnh trong cc mng qung b

00:11:24:79:8e:8200000000 00010001 00100100 01111001 10001110 10000010

HEX

OUI Gn bi nh sn xut

OUI (Organizationally Unique Identifier): M nh sn xut

Mi nh sn xut c cc gi tr OUI ring

Mt nh sn xut c th c nhiu OUI

BIN


a ch dng trong tng lin kt d liu

a ch IP

Dng trong giao thc IP - Internet Protocol (tng mng)

Gi tr ph thuc tng mng, mi card mng c gn mt a ch IP

S dng nh danh my tnh trong mt mng IP

v d :

133.113.215.10 (ipv4)

2001:200:0:8803::53 (ipv6)


nh danh dng trn Internet


a ch s dng trong tng giao vn

S hiu cng: Mt a ch ph, dng km theo a ch IP

Cc ng dng c nh danh bi mt a ch IP v mt s hiu cng

E.g. HTTP cng 80, FTP cng 20, 21

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Cc RFC quan trng

RFC Document Giao thc

RFC 821 SMTP (email, outgoing)

RFC 954 WHOIS

RFC 959 FTP (uploading and downloading)

RFC 1939 POP3 (email, incoming)

RFC 2616 HTTP (Web browsing)

RFC 793 TCP (runs under all above protocols)

RFC 792 ICMP (ping)

RFC 791 IP (runs under TCP and ICMP)


43


C bn v mng my tnh

M hinh truyn thng

Cc m hnh tham chiu



M hnh Client / Server

44

X l

Yu cu

Phc v

Lng nghe yu cu

Nhn yu cu

X l yu cu

Gi kt qu tr v

cho Client

To ra 1 yu cu

Gi yu cu qua Server

Ch Server x l

Nhn kt qu tr v v

x l theo mc ch ring

Dng thc ca thng ip phi tun theo protocol ca dch v.


Web Client

Web Serverfile1.htm

Trnh duytTrang

Web

X l

M hnh Client-Server ca dch v WEB:


Cc ch giao tip:

Ch giao tip nghn Ch giao tip khng nghn

Cc kiu kin trc chng trnh

Chc nng ca 1 chng trnh ng dng:

Giao din ngi dng (User Interface):

Tng tc vi ngi dng

Nhp liu, bo biu, thng bo ra mn hnh,

Dch v nghip v (Business Rule):

Tnh ton d liu

X l thng tin

Dch v lu tr (Data Storage):

Lu tr d liu

Truy vn d liu


GOLDMAN: CSIS FIG. 01-11

Presentation

Application

Data

Communication

Presentation Logic

Interfaces to Presentation GUI

Business Logic Actual Program

Rules

Database Logic Interfaces to DBMS

in Data Layer

Presentation Logic

Interfaces to Presentation GUI

Business Logic Actual Program

Rules

Database Logic Interfaces to DBMS

in Data Layer

Presentation

Application

Data

CLIENT SERVER

M hinh ca 1 chng trinh ng dng


Kin truc n tng:

User Interface

Business Rule

Data Storage

S dng trn 1 my tnh

D ci t

Nhiu nhc im

Cn c kin trc mi Client/Server


Kin truc 2 tng (2-tiered):

Client/Server kiu Fat Client

Client/Server kiu Fat Server


51

Kin truc a tng (n tiered):

Thng gi l ng dng phn tn.

Mi thnh phn c nhim v ring.

M hnh Client/Server 3 tng

Client

Application Server

Database Server

Middleware


GOLDMAN: CSIS FIG. 01-24

Fat Client Fat Server

TWO-TIERED ARCHITECTURE

THREE-TIERED ARCHITECTURES

Presentation Logic

Database Logic

Middleware

CLI

EN

TS

TIE

R 1

TIE

R 2

DE

PA

RTM

EN

TAL

SE

RV

ER

S

TIE

R 3

SU

PE

R-S

ER

VE

RS

M

AIN

FRA

ME

S

Business Logic

Database Logic

Business Logic

Presentation Logic Presentation Logic

Business Logic

Database Logic

So snh kin truc 2 tng v kin truc

3 tng ca ng dng

53

Sockets cung cp mt interface lp trnh mng ti tng Transport.

Mt socket l mt end-point ca mt lin kt gia hai ng dng mng.

Nhiu NNLT: C, C++, Java, VB, C#, . . .

Windows Socket Application Programming Interface (Winsock API)

Winsock h tr xy dng cc ng dng mng trn nn TCP/IP.

.NET h tr lp trnh mng tt nht so vi cc sn phm khc ca

Microsoft

=> Mc tiu: nghin cu cch xy dng ng dng truyn thng

client/server dng Sockets

Gii thiu v Socket


54

Gii thiu v Windows Socket

Windows Sockets Application Programming Interface (WinSock API) l

mt giao din lp trnh mng di nn tng ca Windows.

u tin Windows Socket c pht trin cho h iu hnh Linux,

nhng nay n c ci t trn Windows v h tr c ch iu

khin thng ip t nhin ca Windows.

Windows Socket pht trin qua nhiu phin bn

Vd phin bn chy

trn Windows XP v 2000 l 2.2

Gii thiu v Socket


55

Gii thiu v Windows Socket

Windows Sockets cho php nhng nh sn xut cung cp mt giao

din ng nht ngi lp trnh c th vit cc chng trnh ng

dng theo nhng c t ca Windows Sockets v c th chy c

trn bt k h thng no c h tr Windows Sockets.

Cc phin bn sau ca Windows socket u tng thch vi cc phin

bn trc ca n. iu c ngha l mt ng dng c vit cho

phin bn trc cng hon ton c th chy c trn phin bn sau

ca Windows Sockets.

Windows Sockets h tr nhiu giao thc khc: IPX/SPX, Apples

Appletalk, ATM,.

Gii thiu v Socket


56

Mt s khi nim

Socket: Mt im giao tip u cui ca mt chng trnh trn mng.

Mt TCP/IP Sockets c xc nh bng s kt ni ca mt a ch v

mt s hiu cng

a ch s xc nh my m Sockets lm vic

Cng s xc nh chnh xc tin trnh ang thc hin Sockets trn

my c a ch .

Gii thiu v Socket


57

Khi nim a ch v cng (Address & Port)


58



Nguyn ly

Trong my c rt nhiu ng dng mun trao i vi cc ng dng khc

thng qua mng.

V d: c 2 ng dng ca my A mun trao i vi vi 2 ng dng trn my

B

Mi my tnh ch c duy nht mt ng truyn d liu ( gi v nhn)

Vn

C th xy ra "nhm ln" khi d liu t my A gi n my B th trn my

B khng bit l d liu gi cho ng dng no?

Mi ng dng trn my B s c gn mt s hiu (cng: Port), t

0..65535.

59



Cch gii quyt

Khi ng dng trn my A mun gi cho ng dng no trn my B th ch

vic in thm s hiu cng (vo trng RemotePort) vo gi tin cn gi.

Trn my B, cc ng dng ch vic kim tra gi tr cng trn mi gi tin

xem c trng vi s hiu cng ca mnh ( c gn chnh l gi tr

LocalPort) hay khng? Nu bng th x l, tri li th khng lm g (v

khng phi l ca mnh).

60



Mt s quy nh

Khng bao gi c 2 ng dng li cng dng 1 port

Cc port t 0 1023 (Well-know): dng cho cc ng dng quan trng

trn h iu hnh

Cc port t 1024 49151 (Registered): dnh cho ngi lp trnh (khuyn

co tun theo)

Cc port t 49152 65535 (Dynamic): d tr

61

Giao tip s dng socket c th ch hng kt ni (giao thc TCP)

hoc khng hng kt ni (giao thc UDP) bng cch xc nh giao thc

ca tng vn chuyn.

Lp trnh Socket vi C#


port port

Network driver

Network protocol

Transport protocol

Network driver

Network protocol

Transport protocol

Program A Program B

Host1 Host2

Giao tip gia hai qu trnh s dng Socket

port port

62



Ch c ni kt (connection):

Tn ti knh giao tip o gia client v server.

D liu c gi i theo ch bo m:

Kim tra li.

Truyn li gi tin li, mt

Bo m th t cc gi tin

. . .

D liu chnh xc, Tc truyn chm.

Ch khng ni kt

(connectionless):

Khng tn ti knh giao tip o gia

client v server.

D liu c gi i theo ch khng bo m:

Khng kim tra li.

Khng pht hin, khng truyn li

gi tin li, mt.

Khng bo m th t cc gi tin

. . .

D liu khng chnh xc, tc

truyn nhanh.

Thch hp cho cc ng dng cn tc

, khng cn chnh xc cao: truyn

m thanh, hnh nh . . .

63

Giao tip s dng socket c th ch hng kt ni (giao thc TCP)

hoc khng hng kt ni (giao thc UDP) bng cch xc nh giao thc

ca tng vn chuyn.



64

Cc lp trong .NET Framework c to ra cung cp mt giao din

d dng cho cc lp trnh vin.

Ni dung phn ny s gm:

IP Addresses in C#

Using C# Sockets



Lp IPAddress

Trn Internet mi mt trm (c th l my tnh, my in, thit b ) u cmt nh danh duy nht, nh danh thng c gi l mt a ch(Address).

a ch trn Internet l mt tp hp gm 4 con s c gi tr t 0-255 vcch nhau bi du chm.

th hin a ch ny, ngi ta c th vit di cc dng sau:

Tn: v d nh May01, Server,

a ch IP nhng t trong mt chui: "192.168.1.1", "127.0.0.1

t trong mt mng 4 byte, mi byte cha mt s t 0-255.

Hoc cng c th l mt s (long), c di 4 byte. V d, vi a ch192.168.1.2 trn th gi tr s l 33663168 (s h thp phn khi xplin 4 byte trn li vi nhau) 00000010000000011010100011000000

13/07/2016 652 (byte 0) 1 (byte 1) 168 (byte 2) 192 (byte 3)

Lp IPAddress

Nh vy, i mt a ch chun ra dng s chng ta ch vic tnh ton

cho tng thnh phn.

V d: i a ch 192.168.1.2 ra s, ta tnh nh sau:

2 * 256 ^ 3 + 1 * 256 ^ 2 + 168 * 256 ^ 1 + 192 * 256 ^ 0 =

33663168

IPAddress c s dng biu hin mt a ch IP duy nht

Hm to l : public IPAddress(long address)

Tuy nhin hm to ny khng c s dng thng xuyn.

Lp IPAddress cung cp mt s phng thc khc lm vic vi a ch

IP

13/07/2016 66

Lp IPAddress: cc thnh vin

Tn phng thc M t

AddressFamily

Tr v h a ch ca a ch IP hin hnh. Nu a ch

dng IPv4 th kt qu l Internetwork v

InternetworkV6 nu l a ch IPv6.

Constructor

- IPAddress(S_Long) To a ch IP t mt s

kiu long

- IPAddress(Mng_Byte) To a ch IP t mt

mng byte (4 byte).

GetAddressBytes Chuyn a ch thnh mng byte (4 byte).

HostToNetworkOrdero th t byte ca mt s cho ng vi th t byte

trong a ch IPAddress.

13/07/2016 67

ms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/cpref10/html/P_System_Net_IPAddress_AddressFamily.htmms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/cpref10/html/M_System_Net_IPAddress_GetAddressBytes.htmms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/cpref10/html/O_T_System_Net_IPAddress_HostToNetworkOrder.htm


Tn phng thc M t

IsLoopback Cho bit a ch c phi l a ch lp hay khng?

NetworkToHostOrdero th t byte ca mt a ch cho ng vi th t

byte thng thng.

ParseChuyn mt a ch IP dng chui thnh mt a ch

IP chun (Mt i tng IPAddress)

ToStringTr v a ch IP (mt chui) nhng dng k php

c du chm. (V d "192.168.1.1").

TryParse (S: String)Kim tra xem mt a ch IP ( dng chui) c phi

ng l a ch IP hp l hay khng? True = ng

13/07/2016 68

ms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/cpref10/html/M_System_Net_IPAddress_IsLoopback_1_60004a31.htmms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/cpref10/html/O_T_System_Net_IPAddress_NetworkToHostOrder.htmms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/cpref10/html/M_System_Net_IPAddress_Parse_1_16219e3a.htmms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/cpref10/html/M_System_Net_IPAddress_ToString.htmms-help://MS.VSCC.v80/MS.MSDN.v80/MS.NETDEVFX.v20.en/cpref10/html/M_System_Net_IPAddress_TryParse_1_c5158803.htm

IPAddress: V d to a ch

Cch 1: Dng hm khi to

Byte[] b = new Byte[4];

b[0] = 192;

b[1] = 168;

b[2] = 1;

b[3] = 2;

IPAddress Ip1 = new IPAddress(b);


IPAddress Ip2 = new IPAddress(33663168);


IPAddress Ip3 = IPAddress.Parse(192.168.1.2")

Cch 4: Thng qua tnh ton

Long So = 192* 256^0+168* 256^1+1* 256^2 + 2*256^3;

IPAddress Ip4 = new IPAddress(So);

13/07/2016 69


Tn thuc tnh M t

Any

Cung cp mt a ch IP (thng l 0.0.0.0) ch ra rng

Server phi lng nghe cc hot ng ca Client trn tt c

cc Card mng (s dng khi xy dng Server). Thuc tnh

ny ch c.

Broadcast

Cung cp mt a ch IP qung b (Broadcast, thng l

255.255.255.255), dng s Long. Mun ly dng chui,

vit: Broadcast.ToString(). Thuc tnh ny ch c.

LoopbackTr v mt a ch IP lp (IP Loopback, v d 127.0.0.1).

Thuc tnh ny ch c.

Address

Mt a ch IP (An Internet Protocol (IP) address) dng s

Long. (Mun chuyn sang dng du chm, vit :

Address.ToString())

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IPAddress: V d kim tra a ch

private void KiemTra()

{

IPAddress ip;

String Ip4 = "127.0.0.1";

String Ip5 = "999.0.0.1";

MessageBox.Show(IPAddress.TryParse(Ip4, out ip).ToString());

MessageBox.Show(IPAddress.TryParse(Ip5, out ip).ToString());

}

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IPAddress: V d chuyn a ch hin hnh ra mng

void ChuyenDoi()

{

IPAddress Ip3 = new IPAddress(16885952);

Byte[] b= new Byte[4];

b = Ip3.GetAddressBytes();

MessageBox.Show("Address: " + b[0] + "." + b[1] + "." + b[2] + "." + b[3]);

}

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Lp IPEndpoint

Trong mng, hai trm c th trao i thng tin c vi nhau th chng

cn phi bit c a ch (IP) ca nhau v s hiu cng m hai bn dng

trao i thng tin.

Lp IPAddress mi ch cung cp a ch IP (IPAddress), nh vy vn cn

thiu s hiu cng (Port number).

.NET Framework s dng IPEndPoint biu din mt s kt hp gia

cng v a ch IP

Hai hm to ca lp ny l:

IPEndPoint(long address, int port)

IPEndPoint(IPAddress address, int port)

Hm to th 2 c s dng ph bin hn

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Lp IPEndpoint: cc thnh vin

Tn thuc tnh M t

Address Tr v hoc thit lp a ch IP cho endpoint. (Tr v mt i tng IPAddress)

AddressFamily Ly v loi giao thc m Endpoint ny ang s dng.

Port Ly v hoc thit lp s hiu cng ca endpoint.

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Lp IPEndpoint: cc thnh vin

Tn phngthc

M t

IPEndPoint (Int64, Int32)

To mt i tng mi ca lp IPEndPoint, tham s truyn vo l a ch IP ( dng s) v cng s dng giao tip.

IPEndPoint (IPAddress, Int32)

To mt i tng mi ca lp IPEndPoint, Tham s truyn vo l mt a ch IPAddress v s hiu cng dng giao tip. (Tham kho cch to IPAddress phn trn)

Create To mt endpoint t mt a ch socket (socket address).

ToString Tr v a ch IP v s hiu cng theo khun dng aCh: Cng, v d: 192.168.1.1:8080

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Lp IPEndpoint: v d khi to

private void TaoEndpoint()

{

// To mt a ch IP

IPAddress IPAdd = IPAddress.Parse("127.0.0.1");

// Truyn vo cho hm khi to to IPEndpoint

IPEndPoint IPep = new IPEndPoint(IPAdd, 10000);

}

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private void TaoEndPointBoiTenMay()

{

IPAddress IPAdd = new IPAddress();

//to i tng IP t tn ca my thng qua phng thc tnhDns.GetHostAddresses ca lp DNS

IPAdd = Dns.GetHostAddresses("Localhost")[0];

IPEndPoint IPep = new IPEndPoint(IPAdd, 10000);

}

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Lu : V mt my tnh c th c nhiu card mng (Interface) do vy c

th c nhiu hn 1 a ch IP.

Hm GetHostAddresses s tr v cho chng ta mt mng cha tt c cc

a ch .

Chng ta ly ch s l 0 chn a ch ca card mng u tin.

IPHostEntry l lp cha (Container) v thng tin a ch ca cc my trm

trn Internet.

Lu : N ch l ni "cha", do vy trc khi s dng cn phi np"

thng tin vo cho n.

Lp ny rt hay c dng vi lp DNS

13/07/2016 78

Lp IPHostEntry: cc thnh vin

Tn thuc tnh M t

AddressList Ly v hoc thit lp danh sch cc a ch IP lin kt vi

mt host.

Aliases Ly v hoc thit lp danh sch cc b danh (alias) lin kt

vi mt host.

HostName Ly v hoc thit lp DNS name ca host.

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S dng C# Sockets

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System.Net.Sockets namespace c cha cc lp cung cp giao din lp

trinh Net cho cc hm mc thp API winsock

To socket

S dng hm to ca lp Socket

Socket(AddressFamily af, SocketType st, ProtocolType pt)

Trong :

An AddressFamily to define the network type:

A SocketType to define the type of data connection

A ProtocolType to define a specific network protocol

Gi tr ca AddressFamily lun l InterNetwork

Cn gi tr ca SocketType v ProtocolType phi c kt hp ung

S dng C# Sockets

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Bng kt hp

SocketType Protocoltype Description

Dgram Udp Connectionless communication

Stream Tcp Connection-oriented communication

Raw Icmp Internet Control Message Protocol

Raw Raw Plain IP packet communication

V d v to Socket

Socket newsock = Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

S dng C# Sockets

13/07/2016 82

Mt s thuc tnh ca lp Socket

Property Description

AddressFamily Gets the address family of the Socket

Available Gets the amount of data that is ready to be read

Blocking Gets or sets whether the Socket is in blocking mode

Connected Gets a value that indicates if the Socket is connected to a

remote device

Handle Gets the operating system handle for the Socket

LocalEndPoint Gets the local EndPoint object for the Socket

ProtocolType Gets the protocol type of the Socket

RemoteEndPoint Gets the remote EndPoint information for the Socket

SocketType Gets the type of the Socket

DNS (Domain Name Service)

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DNS (Domain Name Service) l mt lp giup chung ta trong vic phn gii

tn min (Domain Resolution) n gin.

Phn gii tn min tc l: u vo l tn ca my trm thi u ra s cho

ta a ch IP tng ng ca my , v d: ServerCNTT 192.168.3.8

Ngoi ra lp Dns cn c rt nhiu phng thc cho chung ta thm thng

tin v my cc b nh tn, a ch, v.v.

System.Net namespace c cha lp Dns trong c cha tt c cc hm

cn thit khi ta lm vic vi h thng tn min.

Trong cc phng thc ny c

Cc phng thc ng b

Cc phng thc khng ng b

Lp DNS: cc thnh vin

Tn phng thc M t

GetHostByAddress

(String IP)

GetHostByAddress

(IPAddress IP)

Tr v thng tin (IPHostEntry) ca trm c a

ch IP c truyn vo.

Thay bng GetHostEntry()

GetHostByName

(String hostname)

Tr v thng tin (IPHostEntry) DNS ca mt

trm b loi b. Thay bng

GetHostEntry()

HostName Cho ta bit tn ca my va c phn gii.

Nu khng phn gii c th c gi tr l a

ch IP.

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Lp DNS: cc thnh vin

Tn phng thc M t

GetHostAddresses (String

IP_Or_HostName)

Tr v tt c cc a ch IP ca mt trm. Kiu

IPAddress

GetHostEntry (String

IP_Or_HostName)

GetHostEntry (IPAddress IP)

Gii p tn hoc a ch IP truyn vo v tr

v mt i tng IPHostEntry tng ng.

GetHostName Ly v tn ca my tnh cc b (String).

Resolve (String Hostname) Chuyn tn ca my hoc a ch IP thnh

IPHostEntry tng ng.

b b, thay bng GetHostEntry()

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Lu : y l cc phng thc tnh, do vy khi gi thi gi trc tip t tn lp m khng cn phi khai bo mt i tng mi ca lp ny.

V d: Dns.Resolve, Dns.GetHostname, Dns.GetHostEntry, v.v

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Lp DNS: v d 1

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private void ShowIPs()

{

// Ly tt c a ch IP ca my

IPAddress[] add = Dns.GetHostAddresses("PC");

foreach (IPAddress ip in add) {

MessageBox.Show(ip.ToString());

}

//Cch 2

//for (int i = 0; i < add.Length; i++)

//{

// MessageBox.Show(add[i].ToString());

//}

}

Lp DNS: v d 2

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private void CreatIPHostEntry() {

IPHostEntry iphe1, iphe2, iphe3;

IPAddress ipadd = IPAddress.Parse("127.0.0.1");

iphe1 = Dns.GetHostEntry("Notebook");

iphe2 = Dns.GetHostEntry("127.0.0.1");

iphe3 = Dns.GetHostEntry(ipadd);

MessageBox.Show(iphe1.HostName); MessageBox.Show(iphe2.HostName) ;

MessageBox.Show(iphe3.HostName) ;

}

88

C bn v mng my tnh

M hinh truyn thng

Cc m hinh tham chiu


TM LC BI HC


89Chng 1: Nhng vn c bn ca lp trnh mng

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