I /07/30 Dependable Network Innovation Center, Japan Advanced Institute of Science and Technology

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1 I /07/30 Dependable Network Innovation Center, Japan Advanced Institute of Science and Technology

2 I/O Japan Advanced Institute of Science and Technology 2013/07/30 1

3 fork/pthread create I/O Japan Advanced Institute of Science and Technology 2013/07/30 2

4 errno EAGAIN EINPROGRESS fcntl fd = socket(...); opt = O_NONBLOCK; ik = fcntl(fd, F_SETFL, opt); Japan Advanced Institute of Science and Technology 2013/07/30 3

5 (cont.) fd = socket(...); opt = fcntl(fd, F_GETFL, 0); opt = O_NONBLOCK; ik = fcntl(fd, F_SETFL, opt); XOR opt = fcntl(fd, F_GETFL, 0); opt ˆ= O_NONBLOCK; ik = fcntl(fd, F_SETFL, opt); Japan Advanced Institute of Science and Technology 2013/07/30 4

6 ... while(1) { nr = read(fd, buf, BUFSIZ); } busy loop CPU select/poll select/poll Japan Advanced Institute of Science and Technology 2013/07/30 5

7 (cont.) while(1) { nr = read(fd, buf, BUFSIZ); sleep(1); } sleep [s] usleep [us] nanosleep [ns] OS Japan Advanced Institute of Science and Technology 2013/07/30 6

8 select (1.5 select FD_ZERO(&fds) FD_SET(fd, &fds) tw.tv_sec = 1; tw.tc_usec = 500*1000; while(1) { memset(&rfd, &fds, sizeof(fds)); ik = select(fd+1, &rfds, NULL, NULL, &tw); if(ik>0) { nr = read(fd, BUF, BUFSIZ); } } 1.5 Japan Advanced Institute of Science and Technology 2013/07/30 7

9 select (cont.) read select setitimer Japan Advanced Institute of Science and Technology 2013/07/30 8

10 connect connect TCP client connect() start end SYN SYN+ACK ACK server ms ms Japan Advanced Institute of Science and Technology 2013/07/30 9

11 connect (cont.) fd = socket(...) ik = enable_nonblock(fd) ik = connect(fd,...) if(ik<0 && errno!=einprogess) { connect } if(iswritable(fd)) { ik = scanerror(fd, &err) if(err) { connect } disable_nonblock(fd) } Japan Advanced Institute of Science and Technology 2013/07/30 10

12 connect (cont.) enable noblock: disable noblock: iswritable: connect ik = select(nfd,null,wfds,null,null) scanerror: getsockopt errno Japan Advanced Institute of Science and Technology 2013/07/30 11

13 connect time gethostbyname connect write idle idle connect gethostbyname/getaddrinfo write Japan Advanced Institute of Science and Technology 2013/07/30 12

14 gethostbyname IP DNS UDP resolver DNS client (client) resolver request reponse DNS server user functions libc gethostbyname Japan Advanced Institute of Science and Technology 2013/07/30 13

15 gethostbyname (cont.) client resolver UDP DNS server server TCP Japan Advanced Institute of Science and Technology 2013/07/30 14

16 gethostbyname (cont.) client resolver W R DNSserver server C W R Japan Advanced Institute of Science and Technology 2013/07/30 15

17 gethostbyname (cont.) 1) resolver resolver TCP resolver connect, read 2) 3) resolver Japan Advanced Institute of Science and Technology 2013/07/30 16

18 1: resolver resolver gethostbyname TCP TCP TCP UDP 1 2 resolver DNS server 3 client server TCP Japan Advanced Institute of Science and Technology 2013/07/30 17

19 1: resolver (cont.) client resolver DNSserver server C W W R R C W R Japan Advanced Institute of Science and Technology 2013/07/30 18

20 2: gethostbyname gethostbyname gethostbyname unbound Japan Advanced Institute of Science and Technology 2013/07/30 19

21 3: resolver UDP DNS UDNS, adns, libdns light weight resolver Japan Advanced Institute of Science and Technology 2013/07/30 20

22 libc gethostbyname OS resolv.conf NetManager Japan Advanced Institute of Science and Technology 2013/07/30 21

23 EINTR EAGAIN EINPROGRESS ECONNRESET EPIPE Japan Advanced Institute of Science and Technology 2013/07/30 22

24 : EINTR EINTR try_accept: sfd = accept(lfd,...) if(sfd<0) { if(errno==einter) { goto try_accept: }... } EINTR EAGAIN OS Japan Advanced Institute of Science and Technology 2013/07/30 23

25 : EPIPE EPIPE nw = write(sfd,...) if(nw<0) { if(errno==epipe) { return -1 }... } EPIPE return exit Japan Advanced Institute of Science and Technology 2013/07/30 24

26 PIPE EPIPE signal signal(sigpipe, SIG_IGN); POSIX sigaction Japan Advanced Institute of Science and Technology 2013/07/30 25

27 1 2 3 Japan Advanced Institute of Science and Technology 2013/07/30 26

28 (cont.) 2 shm: shmget, shmat, shmdt key id mmap OS shm OS semaphore Japan Advanced Institute of Science and Technology 2013/07/30 27

29 S... R Japan Advanced Institute of Science and Technology 2013/07/30 28

30 IP flag = 1; setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag)); Japan Advanced Institute of Science and Technology 2013/07/30 29

31 (cont.) fd sendmsg, recvmsg fd S FD R msghdr, iovec Japan Advanced Institute of Science and Technology 2013/07/30 30

32 : (proxy server) Japan Advanced Institute of Science and Technology 2013/07/30 31

33 : (cont.) forward proxy // C FP Internet S reverse proxy C Internet RP S Japan Advanced Institute of Science and Technology 2013/07/30 32

34 : C FTP HTTP SMTP HTTP FTP ICP Japan Advanced Institute of Science and Technology 2013/07/30 33 S

35 : (cont.) CUI GUI A B C BBABABBACCACACC Japan Advanced Institute of Science and Technology 2013/07/30 34

36 : (cont.) listen fd port A port B Japan Advanced Institute of Science and Technology 2013/07/30 35

37 Apache, nginx Squid ab(apache ), httperf, JMeter WebPolygraph Japan Advanced Institute of Science and Technology 2013/07/30 36

38 Japan Advanced Institute of Science and Technology 2013/07/30 37

39 configure configure make % gtar ztvf some.tar.gz % cd some %./configure % make OS UNIX BSD, Linux, Solaris, MacOS Linux Japan Advanced Institute of Science and Technology 2013/07/30 38

40 configure (cont.) configure autoconf configure.in autoconf configure Makefile config.h Makefile.in config.h.in configure Makefile config.h config.h Japan Advanced Institute of Science and Technology 2013/07/30 39

41 configure (cont.) config.h #define HAVE_SELECT.c.h #ifdef HAVE_SELECT #define isreadable isreadable_select #else #define isreadable isreadable_poll #endif Makefile automake Japan Advanced Institute of Science and Technology 2013/07/30 40

1) // 2) I/O 3) Japan Advanced Institute of Science and Technology 2013/07/26 1

I441 2013/07/26 Dependable Network Innovation Center, Japan Advanced Institute of Science and Technology 1) // 2) I/O 3) Japan Advanced Institute of Science and Technology 2013/07/26 1 1) Comer: Internetworking