CHAPTER 4: INTERPROCESS COMMUNICATION AND COORDINATION

Transcription

1 CHAPTER : INTERPROCESS COMMUNICATION AND COORDINATION Chapter outline Dicu three level of communication: baic meage paing, requet/reply and tranaction communication baed on meage paing Dicu name ervice for communication Show example of proce coordination uing meage paing Baic meage paing communication Communication primitive: end(detination, meage) receive(ource, meage) channel naming = proce name, link, mailbox, port direct communication: ymmetric/aymmetric proce naming, link indirect communication: many-to-many mailbox, many-to-one port

2 Meage buffering and ynchronization ender ource network detination receiver kernel meage kernel requet 8 7 ack 6 5 reply. Nonblocking end, +8 : Sender proce i releaed after meage ha been compoed and copied into ender kernel.. Blocking end, : Sender proce i releaed after meage h a been tranmitted to the network.. Reliable blocking end, : Sender proce i releaed af ter meage ha been received by the receiver kernel.. Explicit blocking end, : Sender proce i releae d after meage ha been received by the receiver proce. 5. Requet and reply, -, ervice, 5-8 : Sender proce i releaed a fter meage ha been proceed by the receiver and repone returned to the ender.

3 Meage paing API Pipe: A FIFO byte-tream unidirectional link for related procee Meage queue: A tructured variable length meage queue Named Pipe: A pecial FIFO file pipe uing path name for unrelated procee under the ame domain Socket: A logical communication endpoint for communication between autonomou domain Connectionle ocket communication peer procee ocket logical communication endpoint (ocket, LCE) bind phyical communication endpoint (PCE) peer proce ocket logical communication endpoint (ocket, LCE) bind phyical communication endpoint (PCE) endto / recvfrom

4 Connection-oriented ocket communication Server ocket Client ocket bind liten accept read write rendezvou requet reply connect write read

5 Secure Socket Layer protocol Privacy: ue ymmetric private-key cryptography Integrity: ue meage integrity check Authenticity: ue aymmetric public-key cryptography CLIENT SERVER ClientHello randomc, CipherSuite randoms, CipherSuite, eion id erver public key ServerHello ServerKeyExchange ClientKeyExchange encrypted pre-materecret ChangeCipherSpec Finihed Socket Meage hahed meage and ecret encrypted and igned ChangeCipherSpec Finihed Socket Meage 5

6 roup communication and multicat Bet effort All or none Orderly delivery FIFO Caual order Total order (a) (b) (c) (d) 6

7 Caual order Accept meage m if T i = S i + and T k S k for all k i. Delay meage m if T i > S i + or there exit a k i uch that T k > S k. Reject the meage if T i S i. Total order,6 5 (mg m ) 8,9,5 7,5 g Multicat Meage m 0 Acknowledge Commit Time Time delivered,8 7,7 5,7 g m m m pending (mg m ) 6,8 Buffer management in the communication handler 7

8 Requet/reply communication Remote Procedure Call (RPC) Client Server return reply call requet call requet return reply Client Stub meage to parameter to parameter meage Server Stub meage to parameter to parameter meage Tranport Tranport receive end receive end Parameter paing and data converion Binding Compilation Exception and failure handling Security 8

9 RPC Binding erver machine addre or handle to erver directory erver (binder or trader) regiter ervice client create port # port mapper regiter program, verion, and port client machine client handle erver erver machine RPC compilation erver procedure compilation erver program interface pecification RPC generator erver tub header file RPC run-time library client tub client main program compilation client program 9

10 RPC exception and failure Exception: in-band or out-band ignaling Link failure: retranmiion, equence number and idempotent requet, ue of tranaction id xid Server crah: at leat once: erver raie an exception and client retrie at mot once: erver raie an exception and client give up maybe: erver raie no exception and client retrie Client crah: orphan killed by client orphan killed by erver orphan killed by expiration 0

11 Secure RPC C and S are 8-bit random number. C p = α C mod M, and S p = α S mod contant. M, where α and M are known SK c = Sp C SK c = Cp S = (α S ) C = α S C = (α C ) S = α C S NIS erver uer id and paword login proce key erver C Sp record of. uer network name. public and encrypted ecret key Cp S key erver client proce {CK} eion key -> {RPC meage} CK erver proce Client machine Server machine

12 Tranaction Communication ACID propertie Atomicity Conitency Iolation Durability Two-phae commit protocol COORDINATOR PARTICIPANT Phae Phae - precommit the tranaction - end requet to all participant requet - received requet meage - if ready then precommit and end YES - collect all replie - if all vote are unanimou YES reply ele abort tranaction and end NO then commit and end COMMIT ele abort and end ABORT deciion - receive deciion - if COMMIT then commit - if ABORT then abort - received repone reult - end repone

13 Failure and recovery of the PC protocol Coordinator failure recovery action abort abort or continue pre- end collect commit end receive commit requet reply commit repone reend commit meage begin end begin receive requet pre- end receive end commit reply commit commit rep. update end abort find out commit or abort continue Participant failure recovery action

14 Name and Directory Service Object attribute and name tructure Service /object Attribute < attribute > < name, attribute, addre > < name, type, attribute, addre > Name Structure flat tructure hierarchical tructure name-baed reolution (e.g., white page) tructure-free attribute-baed reolution (e.g., yellow page) Attribute Partitioning phyical organizational functional Name pace and information bae DSA DSA A Root B Country C D E Organization Uer DSA

15 Name reolution DUA DSA DSA DUA DSA DSA Recurive chaining Tranitive chaining DSA DSA DUA DUA DSA DSA Referral Multicat 5

16 Ditributed Mutual Excluion Contention-baed: Timetamp prioritized Voting Control (Token)-baed: Ring tructure Tree tructure Broadcat tructure Tree-tructure token paing

17 Broadcat tructure token paing * Proce Proce 0 8 * Proce * Proce Sequence vector Si Token vector T Token queue Q 7

18 Leader Election Complete topology The Bully algorithm Logic ring topology The initiator node et partcipating = true and end (id) to it ucceor node; For each proce node, receive (value); cae value > id : participating := true, end (value); value < id and participating == fale : participating := true, value == id : announce leader; end cae end (id); Tree topology 8