dive into network_programming

Some Basics of TCP/IP ProtocolNotes for Building Your Own Sockets Application

Common Server ModelsCommon Client Models

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Dive into Socket Programming

LiLi

August 16, 2013

LiLi Dive into Socket Programming



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OutLine

I Some Basics of TCP/IP ProtocolI TIME WAIT CLOSE WAITI SO REUSEADDR SO LINGERI TCP NODELY TCP QUICKACKI Socket BufferI SIG PIPEI KeepAliveI close shudown

I Notes for Building Your Own Sockets ApplicationI Manage Your Own Application-Layer BufferI Async Connect/AcceptI Thundering Herd




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I Common Server ModelsI thread-per-connectionI reactorI reactor + worker threadI multiple reactors

I Common Client ModelsI connection poolI async io + event loop

I OthersI C10k C100k ...




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TIME WAIT CLOSE WAIT




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TIME WAIT CLOSE WAIT

I active close —— TIME WAIT

I passive close —— CLOSE WAIT

I read returns 0peer has closed connection, invoke close

I TIME WAIT will last 2MSL max segment lifetime




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SO REUSERADDR SO LINGER

I SO REUSEADDRwhen server crashes, the port remains in TIME WAIT. Servercan’t restart immediately?set SO REUSEADDR

I SO LINGERCan set SO LINGER to prevent entering TIME WAIT. Thisalso discards any unsent data.don’t do this!!! why?




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TCP NODELY TCP QUICKACK

I TCP NODELYNagle’s algorithm

I TCP CORKwhen transmit files

I TCP QUICKACKdelayed ackmust set the option every time




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Socket Buffer

buffer size = 2 * Bandwidth * Delay

how to measure delay?




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SIG PIPE

I Write a Closed Socket Twice:first time, ok, receive RSTsecond time, SIG PIPE, crash

I Ignore the Signal:signal(SIGPIPE,SIG IGN)




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KeepAlive

I KeepAlive optionToo Long, 2 hours 11mins you know peer is dead

I Heartbeat in your own application




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close shutdown

I shutdown can only shutdown one directionshutdown write,can still read

I shutdown does not close the file descriptor,still need close




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Manage Your Own Application-Layer Buffer

I readcan read all one time ?

I writecan write all one time ?

I trigered from event loopread to your own bufferwrite from your own buffer




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Async Connect/Accept

I Blocked connect/acceptMaybe Too Long

I Async acceptEWOULDBLOCKadd listen fd to event loop

I Async connectEINPROCESSadd connect fd to event loop




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Thundering Herd

I acceptno longer a problem in kernel now

I epoll waitstill a problem

I how to solve?lighthttpdnginx




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thread-per-connection

I create a new thread for each connection

I Before NIO,Java use this




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reactor

I simple event loop

I Example:Redis




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reactor+ worker thread

I event loop + worker thead pool

I Example:tbnet




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multiple reactors

I event loop each thread/process

I Example:memcachednginxlighthttpd




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connection pool

I create a set pf connection each client

I Example:Jedis




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async io + event loop

I event loop

I Example:Minatbnet




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I C10k C100kepoll1000Mbit/s one event loop —by zeromq guide

I C1M C10M...I More Challenges:

softirqmemory...

I dive into kernel


dive into network_programming

Technology

application lili dive

socket programming lili

basics of tcpip protocol

basics of tcpip protocol

close lili dive

close wait lili dive

buer lili dive

redis lili dive