TCP通信の基礎 - sbcr.jp

1 1. Chapter 2. 2. 3. TCP 4. Chapter 2 TCP .. 5. TCP . TCP .. Web . 6. 7. 25 1:23:52 PM. Chapter2 TCP 2-1 TCP .. 2-1 TCP .. 1. 2-2 . TCP 2 .. 2.. socket socket .. 3.. socket TCP . API. Application Programming 4. Interface API POSIX . 2-1 . socket . Linux . 5. 2-1 Linux socket . 32 .. socket . List 2-1 socket 6. #include < >. sockfd = socket(. int socket_family, / /. int socket_type, / /. int protocol / /. API ); 7. 2 .. 3 . 2-1 . 26 27. 26-27 1:23:53 PM. Chapter2 TCP 2-1 TCP . socket 3 .. socket_family SOCK_STREAM . 1. 2-1 . IPv4 AF_INET IPv6 AF_INET6 SOCK_DGRAM .. 2-1 2. AF_INET SOCK_STREAM TCP . AF_INET IPv4 . AF_INET6 IPv6 . AF_UNIX AF_LOCAL SOCK_DGRAM . AF_PACKET .. 3. SOCK_STREAM SOCK_. 2 socket_type DGRAM 2-3 . Linux.

2 2-3 2 . 2-2 man 2 socket .. SOCK_STREAM 4. SOCK_DGRAM . SOCK_STREAM byte stream . out-of-band . SOCK_DGRAM . SOCK_SEQPACKET . socket 3 protocol .. 3 5. SOCK_RAW . SOCK_RDM . 0 . SOCK_PACKET IP /etc/protocols . $sudo cat ./etc/protocols . AF_INET SOCK_STREAM IPv4 TCP AF_INET # Internet (IP) protocols 6. #. SOCK_DGRAM IPv4 UDP IPv6 AF_ # Updated from and other INET6+SOCK_STREAM IPv6 TCP AF_INET6 SOCK_DGRAM IPv6 UDP # sources. # New protocols will be added on request if they have been officially . # assigned by IANA and are not historical. AF_UNIX SOCK_STREAM AF_UNIX SOCK_DGRAM AF_INET SOCK_RAW RAW # If you need a huge list of used numbers please install the nmap package. AF_UNIX Chapter 6 SOCK_RAW Chapter 12 . SOCK_STREAM.

3 Ip 0 IP # internet protocol, pseudo protocol number 7. #hopopt 0 HOPOPT # IPv6 Hop-by-Hop Option [RFC1883]. SOCK_DGRAM 2 icmp 1 ICMP # internet control message protocol igmp 2 IGMP # Internet Group Management SOCK_STREAM . 28 29. 28-29 1:23:55 PM. Chapter2 TCP 2-1 TCP . int . ggp 3 GGP # gateway-gateway protocol ipencap 4 IP-ENCAP # IP encapsulated in IP (officially ``IP'') . st 5 ST # ST datagram mode socket -1 . tcp 6 TCP # transmission control protocol 1. egp 8 EGP # exterior gateway protocol errno Chapter 2-3 . igp 9 IGP # any private interior gateway(Cisco) 0 . pup 12 PUP # PARC universal packet protocol udp 17 UDP # user datagram protocol 0 open . hmp 20 HMP # host monitoring protocol socket socket 0 . xns-idp 22 XNS-IDP # Xerox NS IDP.

4 Rdp 27 RDP # "reliable datagram" protocol 2.. List 2-3 .. if ((soc = socket(AF_INET, SOCK_DGRAM, 0)) <= 0) {. perror("socket");. return -1;. }. 3. socket . AF_INET IPv4 SOCK_STREAM .. <= 0 < 0 . AF_INET+SOCK_STREAM IPv4 TCP . socket 0 . 2-2 . stdin 0 socket . List 2-2 IPv4 TCP .. 4. #include < > List 2-4 0 . #include < >. #include < > #include < >. #include < >. int #include < >. main(). { int 5. int sock; main(). {. sock = socket(AF_INET, SOCK_STREAM, 0); int sock;. if (sock < 0) {. printf("socket failed\n"); printf("fileno(stdin) = %d\n", fileno(stdin));. return 1; close(0);. }. / sock will be zero, and it is not an error! / 6. return 0; sock = socket(AF_INET, SOCK_DGRAM, 0);. } printf("sock=%d\n", sock);. return 0;. socket }.

5 Linux open POSIX . 7.. 2-2 . 30 31. 30-31 1:23:55 PM. Chapter2 TCP 2-2 TCP / . 2-4 POSIX TCP .. 0 stdin bind .. 1 stdout . 1. listen accept 3 . 2 stderr . 2-3 TCP . 2-4 0 . stdin close .. 2-4 fileno stdin . socket socket . printf fileno stdin 2.. 0 close 0 close .. close 0 socket 0 . IP IP .. 0 socket . 3. 0 bind .. COLUMN listen .. 4. OS API. Application Programming Interface accept connect .. read write . open read write . malloc .. 5. getaddrinfo write read . man 2 3 . close close .. 6. bind . 2-2 TCP / . listen . connect . TCP accept 7. Chap . ter 2 TCP TCP accept . 32 33. 32-33 1:23:57 PM. Chapter2 TCP 2-2 TCP / . TCP . TCP . TCP . TCP . 1.. IP . IP . IP . bind . TCP .. TCP .. 2.. TCP . TCP .. TCP .. 2-4 TCP .. / close 3.

6 Linux TCP List 2-5 TCP . port 11111.. List 2-5 TCP 4. #include < >. #include < >. #include < >. port 80 #include < >. #include < >. port 80. port 32879 int 5. port 80. main(). port 41901 {. int sock0;. struct sockaddr_in addr;. struct sockaddr_in client;. int len;. int sock; 6. / /. TCP sock0 = socket(AF_INET, SOCK_STREAM, 0);. / /. = AF_INET;. TCP TCP = htons(12345);. HELLO = INADDR_ANY; 7. bind(sock0, (struct sockaddr )&addr, sizeof(addr)); 1. / TCP /. 34 35. 34-35 1:23:59 PM. Chapter2 TCP 2-2 TCP / . List 2-6 TCP . listen(sock0, 5);. #include < >. / TCP / #include < >. len = sizeof(client); #include < > 1. sock = accept(sock0, (struct sockaddr )&client, 2 #include < >. #include < >. / 5 /. write(sock, "HELLO", 5); 3 int main().)}

7 / TCP / {. close(sock); struct sockaddr_in server; 2. int sock;. / listen socket / char buf[32];. close(sock0); int n;. return 0; / /. } sock = socket(AF_INET, SOCK_STREAM, 0);. / / 3. IP bind . 1 = AF_INET;. = htons(12345);. 2 3 . / localhost /. TCP TCP inet_pton(AF_INET, " ", & );. close .. / /. connect(sock, (struct sockaddr )&server, sizeof(server));. 4. / /. TCP memset(buf, 0, sizeof(buf));. n = read(sock, buf, sizeof(buf));. printf("%d, %s\n", n, buf);. TCP TCP . / socket / 5. close(sock);. return 0;. }.. 6. TCP . TCP . HELLO . IP TCP TCP localhost .. IP 7. 2-3 . TCP List 2-6 TCP . 2-3 IP ifconfig -a . 36 37. 36-37 1:23:59 PM. Chapter2 TCP 2-3 .. TCP close close 2-3 . read EOF End Of File 1. 0 . read 0 TCP close .. close.

8 Read .. -1 errno errno . 2. read 0 0 . read 3 0 . read 0 errno perror .. errno . 3. -1 errno . COLUMN List 2-7 .. List 2-7 errno .. #include < >. gcc .. 4.. if (socket() < 0) {. if (errno == ) { }. server }. gcc -o server errno 5. man socket . client .. % man 2 socket gcc -o client 6.. errno .. 2-5 socket errno man . errno . 7. EACCES . EAFNOSUPPORT . EINVAL . 38 39. 38-39 1:24:00 PM. Chapter2 TCP 2-3 . 2-5 socket errno man .. return 0;. errno }. EMFILE . ENFILE . 1. socket . ENOBUFS ENOMEM . EPROTONOSUPPORT -1 if . perror . socket: Socket type not supported 2. perror . : perror .. errno . perror perror("hogehoge");. 3.. List 2-8 perror . #include < > hogehoge: Socket type not supported void perror(. const char string / /.)

9 4. );. printf errno . ESOCKNOSUPPORT define 2-4 . socket perror errno . perror . List 2-9 socket 5. #include < >. #include < > perror . #include < >. #include < >. errno perror . int 6. main() 1 . {. int sock;.. sock = socket(3000, 4000, 5000); List 2-10 . if (sock < 0) {. perror("socket"); #include < >. printf("%d\n", errno); #include < > 7. return 1;. }. 2-4 include ESOCKNOSUPPORT . 40 41. 40-41 1:24:00 PM. Chapter2 TCP 2-3 . #include < > #include < >. #include < >. #include < >. int 1. main() int { main(). int sock; {. sock = socket(AF_INET, 4000, 5000); 1 int sock;. write(-1, "hoge", 4); 2 sock = socket(3000, 4000, 5000);. if (sock < 0) { if (sock < 0) {. perror("socket"); close(fileno(stdout)); 1. 2. return 1; printf("%d\n", errno).}}}}}

10 }. perror("socket");. return 0; return 1;. } }. return 0; 3. }. socket: Bad file descriptor printf perror printf .. 1 close printf . printf EBADF . 4. 1 socket EAFNOSUPPORT errno printf perror . 2 write EBADF errno . EBADF printf printf . perror . printf . 2 perror errno .. 5. bind . printf perror bind . bind .. bind .. 6. printf . perror .. List 2-11 List 2-12 bind listen .. printf printf .. errno . List 2-11 printf perror % . 7. : 56664. #include < >. #include < >. 42 43. 42-43 1:24:01 PM. Chapter2 TCP 2-3 . 56664 . main(). TCP 56664 TCP write {. HOGE\n 5 int s0, sock;. struct sockaddr_in peer; 1. telnet socklen_t peerlen;. 56664 int n;. char buf[1024];. % telnet localhost 56664 / listen() /. Trying s0 = socket(AF_INET, SOCK_STREAM, 0).