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P a 02 r t Chapter 4 TCP Chapter 5 Chapter 6 UDP Chapter 7 Chapter 8 GUI

C h a p t e r 04 TCP

1 3 1 2 3 TCP TCP TCP [ 4 2] listen connect send accept recv send recv [ 4 1] PC Internet Explorer HTTP HTTP HTTP TCP TCP FTP TCP 90 91

1 [ 4 3] [ 4 6] TCP TCP [ 4 3] 9000 bind [ 4 4] TCP [ 4 5] TCP [ 4 6] TCP [ 4 7] 1 1 TCP #n 2 TCP [ 4 8] recv printf send fgets send recv printf 2 92 93

001 #include <winsock2.h> 002 #include <stdlib.h> 003 #include <stdio.h> 004 005 #define BUFSIZE 512 006 007 // 008 void err_quit(char *msg) 009 { 010 LPVOID lpmsgbuf; 011 FormatMessage( 012 FORMAT_MESSAGE_ALLOCATE_BUFFER 013 FORMAT_MESSAGE_FROM_SYSTEM, 014 NULL, WSAGetLastError(), 015 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 016 (LPTSTR)&lpMsgBuf, 0, NULL); 017 MessageBox(NULL, (LPCTSTR)lpMsgBuf, msg, MB_ICONERROR); 018 LocalFree(lpMsgBuf); 019 exit(-1); 020 } 021 022 // 023 void err_display(char *msg) 024 { 025 LPVOID lpmsgbuf; 026 FormatMessage( 027 FORMAT_MESSAGE_ALLOCATE_BUFFER 028 FORMAT_MESSAGE_FROM_SYSTEM, 029 NULL, WSAGetLastError(), 030 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 031 (LPTSTR)&lpMsgBuf, 0, NULL); 032 printf("[%s] %s", msg, (LPCTSTR)lpMsgBuf); 033 LocalFree(lpMsgBuf); 034 } 035 036 int main(int argc, char* argv[]) 037 { 038 int retval; 039 040 // 041 WSADATA wsa; 042 if(wsastartup(makeword(2,2), &wsa)!= 0) 043 return -1; 044 045 // socket() 046 SOCKET listen_sock = socket(af_inet, SOCK_STREAM, 0); 047 if(listen_sock == INVALID_SOCKET) err_quit("socket()"); 048 049 // bind() 050 SOCKADDR_IN serveraddr; 051 ZeroMemory(&serveraddr, sizeof(serveraddr)); 052 serveraddr.sin_family = AF_INET; 053 serveraddr.sin_port = htons(9000); 054 serveraddr.sin_addr.s_addr = htonl(inaddr_any); 055 retval = bind(listen_sock, (SOCKADDR *)&serveraddr, sizeof(serveraddr)); 056 if(retval == SOCKET_ERROR) err_quit("bind()"); 057 058 // listen() 059 retval = listen(listen_sock, SOMAXCONN); 060 if(retval == SOCKET_ERROR) err_quit("listen()"); 061 062 // 063 SOCKET client_sock; 064 SOCKADDR_IN clientaddr; 065 int addrlen; 94 95

066 char buf[bufsize+1]; 067 068 while(1){ 069 // accept() 070 addrlen = sizeof(clientaddr); 071 client_sock = accept(listen_sock, (SOCKADDR *) &clientaddr, &addrlen); 072 if(client_sock == INVALID_SOCKET){ 073 err_display("accept()"); 074 continue; 075 } 076 printf("\n[tcp ] :IP =%s, =%d\n", inet_ntoa(clientaddr.sin_addr), 077 ntohs(clientaddr.sin_port)); 078 079 // 080 while(1){ 081 // 082 retval = recv(client_sock, buf, BUFSIZE, 0); 083 if(retval == SOCKET_ERROR){ 084 err_display("recv()"); 085 break; 086 } 087 else if(retval == 0) 088 break; 089 090 // 091 buf[retval] = '\0'; 092 printf("[tcp/%s:%d] %s\n", inet_ntoa(clientaddr.sin_addr), 093 ntohs(clientaddr.sin_port), buf); 094 095 // 096 retval = send(client_sock, buf, retval, 0); 097 if(retval == SOCKET_ERROR){ 098 err_display("send()"); 099 break; 100 } 101 } 102 103 // closesocket() 104 closesocket(client_sock); 105 printf("[tcp ] : IP =%s, =%d\n", 106 inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port)); 107 } 108 109 // closesocket() 110 closesocket(listen_sock); 111 112 // 113 WSACleanup(); 114 return 0; 115 } 001 #include <winsock2.h> 002 #include <stdlib.h> 003 #include <stdio.h> 004 005 #define BUFSIZE 512 006 007 // 008 void err_quit(char *msg) 009 { 010 LPVOID lpmsgbuf; 011 FormatMessage( 012 FORMAT_MESSAGE_ALLOCATE_BUFFER 013 FORMAT_MESSAGE_FROM_SYSTEM, 014 NULL, WSAGetLastError(), 96 97

015 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 016 (LPTSTR)&lpMsgBuf, 0, NULL); 017 MessageBox(NULL, (LPCTSTR)lpMsgBuf, msg, MB_ICONERROR); 018 LocalFree(lpMsgBuf); 019 exit(-1); 020 } 021 022 // 023 void err_display(char *msg) 024 { 025 LPVOID lpmsgbuf; 026 FormatMessage( 027 FORMAT_MESSAGE_ALLOCATE_BUFFER 028 FORMAT_MESSAGE_FROM_SYSTEM, 029 NULL, WSAGetLastError(), 030 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 031 (LPTSTR)&lpMsgBuf, 0, NULL); 032 printf("[%s] %s", msg, (LPCTSTR)lpMsgBuf); 033 LocalFree(lpMsgBuf); 034 } 035 036 // 037 int recvn(socket s, char *buf, int len, int flags) 038 { 039 int received; 040 char *ptr = buf; 041 int left = len; 042 043 while(left > 0){ 044 received = recv(s, ptr, left, flags); 045 if(received == SOCKET_ERROR) 046 return SOCKET_ERROR; 047 else if(received == 0) 048 break; 049 left -= received; 050 ptr += received; 051 } 052 053 return (len - left); 054 } 055 056 int main(int argc, char* argv[]) 057 { 058 int retval; 059 060 // 061 WSADATA wsa; 062 if(wsastartup(makeword(2,2), &wsa)!= 0) 063 return -1; 064 065 // socket() 066 SOCKET sock = socket(af_inet, SOCK_STREAM, 0); 067 if(sock == INVALID_SOCKET) err_quit("socket()"); 068 069 // connect() 070 SOCKADDR_IN serveraddr; 071 serveraddr.sin_family = AF_INET; 072 serveraddr.sin_port = htons(9000); 073 serveraddr.sin_addr.s_addr = inet_addr("127.0.0.1"); 074 retval = connect(sock, (SOCKADDR *)&serveraddr, sizeof(serveraddr)); 075 if(retval == SOCKET_ERROR) err_quit("connect()"); 076 077 // 078 char buf[bufsize+1]; 079 int len; 080 081 // 082 while(1){ 083 // 084 ZeroMemory(buf, sizeof(buf)); 085 printf("\n[ ]"); 086 if(fgets(buf, BUFSIZE+1, stdin) == NULL) 087 break; 088 98 99

089 // '\n' 090 len = strlen(buf); 091 if(buf[len-1] == '\n') 092 buf[len-1] = '\0'; 093 if(strlen(buf) == 0) 094 break; 095 096 // 097 retval = send(sock, buf, strlen(buf), 0); 098 if(retval == SOCKET_ERROR){ 099 err_display("send()"); 100 break; 101 } 102 printf("[tcp ] %d.\n", retval); 103 104 // 105 retval = recvn(sock, buf, retval, 0); 106 if(retval == SOCKET_ERROR){ 107 err_display("recv()"); 108 break; 109 } 110 else if(retval == 0) 111 break; 112 113 // 114 buf[retval] = '\0'; 115 printf("[tcp ] %d.\n", retval); 116 printf("[ ] %s\n", buf); 117 } 118 119 // closesocket() 120 closesocket(sock); 121 122 // 123 WSACleanup(); 124 return 0; 125 } 100 101

102 103

TCP 1 TCP IP [ 4 20] TCP IP 2 local IP remote IP TCP LISTENING ESTABLISHED 104 105

bind IP 1 TCP [ 4 21] socket bind IP listen TCP LISTENING accept IP send recv closesocket s int bind( SOCKET s, const struct sockaddr* name, int namelen ); IP name TCP IP SOCKADDR_IN IP namelen TCPServer bind 050 SOCKADDR_IN serveraddr; 051 ZeroMemory(&serveraddr, sizeof(serveraddr)); 052 serveraddr.sin_family = AF_INET; 053 serveraddr.sin_port = htons(9000); 054 serveraddr.sin_addr.s_addr = htonl(inaddr_any); 055 retval = bind(listen_sock, (SOCKADDR *)&serveraddr, sizeof(serveraddr)); 056 if(retval == SOCKET_ERROR) err_quit("bind()"); TCP socket closesocket send recv 50 51 0 API ZeroMemory C memset 52 AF_INET 53 9000 htons 106 107

54 IP IP INADDR_ANY IP multihomed host INADDR_ANY 55 56 bind SOCKADDR * listen TCP LISTENING int listen( SOCKET s, int backlog ); s bind IP backlog connection queue backlog SOMAXCONN SOCKADDR_IN serveraddr;... retval = bind(listen_sock, (SOCKADDR *)&serveraddr, sizeof(sockaddr_in)); TCPServer listen 059 retval = listen(listen_sock, SOMAXCONN); 060 if(retval == SOCKET_ERROR) err_quit("listen()"); SOCKADDR_IRDA serveraddr;... retval = bind(listen_sock, (SOCKADDR *)&serveraddr, sizeof(sockaddr_irda));... 59 60 backlog listen SOCKADDR_IRDA serveraddr;... retval = bind(listen_sock, (SOCKADDR *)&serveraddr, sizeof(serveraddr)); accept IP IP IP 108 109

s SOCKET accept( SOCKET s, struct sockaddr* addr, int* addrlen ); addr accept addr IP addrlen addr accept addrlen accept wait state NT 2000 CPU 0 [ 4 22] accept TCPServer accept 062 // 063 SOCKET client_sock; 064 SOCKADDR_IN clientaddr; 065 int addrlen;... 068 while(1){ 069 // accept() 070 addrlen = sizeof(clientaddr); 071 client_sock = accept(listen_sock, (SOCKADDR *) &clientaddr, &addrlen); 072 if(client_sock == INVALID_SOCKET){ 073 err_display("accept()"); 074 continue; 075 } 076 printf("\n[tcp ] : IP =%s, =%d\n", 077 inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port)); 078 079 // 080 while(1){... 101 } 102 103 // closesocket() 104 closesocket(client_sock); 105 printf("[tcp ] : IP =%s, =%d\n", 106 inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port)); 107 } 63 accept SOCKET 64 accept accept IP 65 accept 68 110 111

70 accept addrlen clientaddr 71 75 accept err_display 67 76 77 IP inet_ntoa ntohs 3 2 TCP [ 4 23] socket connect send recv closesocket 80 101 accept send recv 104 106 IP TCP socket closesocket send recv connect connect TCP int connect( SOCKET s, const struct sockaddr* name, int namelen ); 112 113

s name IP namelen bind bind connect IP 1024 5000 [ 4 24] TCP UDP 6 IP send buffer receive buffer socket buffer send recv TCPClient connect 070 SOCKADDR_IN serveraddr; 071 serveraddr.sin_family = AF_INET; 072 serveraddr.sin_port = htons(9000); 073 serveraddr.sin_addr.s_addr = inet_addr("127.0.0.1"); 074 retval = connect(sock, (SOCKADDR *)&serveraddr, sizeof(serveraddr)); 075 if(retval == SOCKET_ERROR) err_quit("connect()"); 70 73 IP 74 75 connect TCP 100 200 300 100 200 300 350 250 TCP 3 send recv WSA* send TCP IP send send 114 115

s int send( SOCKET s, const char* buf, int len, int flags ); connected recv int recv( SOCKET s, char* buf, int len, int flags ); buf len flags send 0 MSG_DONTROUTE 7 SO_DONTROUTE MSG_OOB 9 send blocking send send len wait state len send send len Nonblocking 9 ioctlsocket send send 1 len send recv s connected buf len buf flags recv 0 MSG_PEEK MSG_OOB 9 recv MSG_PEEK recv recv len len closesocket TCP recv 0 recv 0 normal close = graceful close 116 117

recv len TCP recv recvn [ 4 25] 53 left 0 len 037 int recvn(socket s, char *buf, int len, int flags) 038 { 039 int received; 040 char *ptr = buf; 041 int left = len; 042 043 while(left > 0){ 044 received = recv(s, ptr, left, flags); 045 if(received == SOCKET_ERROR) 046 return SOCKET_ERROR; 047 else if(received == 0) 048 break; 049 left -= received; 050 ptr += received; 051 } 052 053 return (len - left); 054 } 37 recvn recv 39 recv 40 ptr ptr 41 left 43 44 46 recv 47 48 recv 0 49 50 ptr left TCPClient send recv 078 char buf[bufsize+1]; 079 int len;... 082 while(1){ 083 // 084 ZeroMemory(buf, sizeof(buf)); 085 printf("\n[ ]"); 086 if(fgets(buf, BUFSIZE+1, stdin) == NULL) 087 break; 088 089 // '\n' 090 len = strlen(buf); 091 if(buf[len-1] == '\n') 092 buf[len-1] = '\0'; 093 if(strlen(buf) == 0) 094 break; 095 096 // 097 retval = send(sock, buf, strlen(buf), 0); 098 if(retval == SOCKET_ERROR){ 099 err_display("send()"); 100 break; 101 } 102 printf("[tcp ] %d.\n", retval); 118 119

103 104 // 105 retval = recvn(sock, buf, retval, 0); 106 if(retval == SOCKET_ERROR){ 107 err_display("recv()"); 108 break; 109 } 110 else if(retval == 0) 111 break; 112 113 // 114 buf[retval] = '\0'; 115 printf("[tcp ] %d.\n", retval); 116 printf("[ ] %s\n", buf); 117 } 78 = 79 84 87 fgets 90 92 \n 93 94 Enter 97 102 send send strlen buf 105 111 recvn recvn 114 116 \0 TCPServer send recv client_sock accept 066 char buf[bufsize+1];... 080 while(1){ 081 // 082 retval = recv(client_sock, buf, BUFSIZE, 0); 083 if(retval == SOCKET_ERROR){ 084 err_display("recv()"); 085 break; 086 } 087 else if(retval == 0) 088 break; 089 090 // 091 buf[retval] = '\0'; 092 printf("[tcp/%s:%d] %s\n", inet_ntoa(clientaddr.sin_addr), 093 ntohs(clientaddr.sin_port), buf); 094 095 // 096 retval = send(client_sock, buf, retval, 0); 097 if(retval == SOCKET_ERROR){ 098 err_display("send()"); 099 break; 100 } 101 } 66 80 recv 0 SOCKET_ERROR 82 88 recv recvn 91 93 \0 96 100 send 120 121

TCP TCP TCP 1 application level [ 4 26] struct DrawMessage1 { int x1, y1; // int x2, y2; // int width; // int color; // }; struct DrawMessage2 { int x1, y1; // int r; // int fillcolor; // int width; // int color; // }; 122 123

struct DrawMessage1 { int type; // = LINE int x1, y1; // int x2, y2; // int width; // int color; // }; struct DrawMessage2 { int type; // = CIRCLE int x1, y1; // int r; // int fillcolor; // int width; // int color; // }; [ ] EOR EOR EOR EOR [ 4 27] recvn 2 TCP [ ] EOR End Of Record 3 124 125

member alignment sizeof msg 10 =4+1+4+1 16 [ 4 28] msg struct MyMessage { int a; // 4 char b; // 1 int c; // 4 char d; // 1 }; MyMessage msg; //... send(sock, (char *)&msg, sizeof(msg), 0); int a; // 4 char b; // 1 int c; // 4 char d; // 1 }; #pragma pack() // MyMessage msg; //... send(sock, (char *)&msg, sizeof(msg), 0); 10 #pragma pack msg [ 4 29] #pragma pack(1) // : 1 struct MyMessage { 126 127

3 TCP IP [ 4 32] 256 4 001 #include <winsock2.h> 002 #include <stdlib.h> 003 #include <stdio.h> 004 005 #define BUFSIZE 4096 006 007 // 008 void err_quit(char *msg) 009 { 010 LPVOID lpmsgbuf; 011 FormatMessage( 012 FORMAT_MESSAGE_ALLOCATE_BUFFER 013 FORMAT_MESSAGE_FROM_SYSTEM, 014 NULL, WSAGetLastError(), 015 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 016 (LPTSTR)&lpMsgBuf, 0, NULL); 017 MessageBox(NULL, (LPCTSTR)lpMsgBuf, msg, MB_ICONERROR); 018 LocalFree(lpMsgBuf); 019 exit(-1); 020 } 021 022 // 023 void err_display(char *msg) 024 { 025 LPVOID lpmsgbuf; 026 FormatMessage( 027 FORMAT_MESSAGE_ALLOCATE_BUFFER 028 FORMAT_MESSAGE_FROM_SYSTEM, 029 NULL, WSAGetLastError(), 030 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 031 (LPTSTR)&lpMsgBuf, 0, NULL); 128 129

032 printf("[%s] %s", msg, (LPCTSTR)lpMsgBuf); 033 LocalFree(lpMsgBuf); 034 } 035 036 int main(int argc, char* argv[]) 037 { 038 int retval; 039 040 if(argc < 2){ 041 fprintf(stderr, "Usage: %s [FileName]\n", argv[0]); 042 return -1; 043 } 044 045 // 046 WSADATA wsa; 047 if(wsastartup(makeword(2,2), &wsa)!= 0) 048 return -1; 049 050 // socket() 051 SOCKET sock = socket(af_inet, SOCK_STREAM, 0); 052 if(sock == INVALID_SOCKET) err_quit("socket()"); 053 054 // connect() 055 SOCKADDR_IN serveraddr; 056 serveraddr.sin_family = AF_INET; 057 serveraddr.sin_port = htons(9000); 058 serveraddr.sin_addr.s_addr = inet_addr("127.0.0.1"); 059 retval = connect(sock, (SOCKADDR *)&serveraddr, sizeof(serveraddr)); 060 if(retval == SOCKET_ERROR) err_quit("connect()"); 061 062 // 063 FILE *fp = fopen(argv[1], "rb"); 064 if(fp == NULL){ 065 perror(" "); 066 return -1; 067 } 068 069 // 070 char filename[256]; 071 ZeroMemory(filename, 256); 072 sprintf(filename, argv[1]); 073 retval = send(sock, filename, 256, 0); 074 if(retval == SOCKET_ERROR) err_quit("send()"); 075 076 // 077 fseek(fp, 0, SEEK_END); 078 int totalbytes = ftell(fp); 079 080 // 081 retval = send(sock, (char *)&totalbytes, sizeof(totalbytes), 0); 082 if(retval == SOCKET_ERROR) err_quit("send()"); 083 084 // 085 char buf[bufsize]; 086 int numread; 087 int numtotal = 0; 088 089 // 090 rewind(fp); // 091 while(1){ 092 numread = fread(buf, 1, BUFSIZE, fp); 093 if(numread > 0){ 094 retval = send(sock, buf, numread, 0); 095 if(retval == SOCKET_ERROR){ 096 err_display("send()"); 097 break; 098 } 099 numtotal += numread; 130 131

100 } 101 else if(numread == 0 && numtotal == totalbytes){ 102 printf("!: %d \n", numtotal); 103 break; 104 } 105 else{ 106 perror(" "); 107 break; 108 } 109 } 110 fclose(fp); 111 112 // closesocket() 113 closesocket(sock); 114 115 // 116 WSACleanup(); 117 return 0; 118 } 001 #include <winsock2.h> 002 #include <stdlib.h> 003 #include <stdio.h> 004 005 #define BUFSIZE 4096 006 007 // 008 void err_quit(char *msg) 009 { 010 LPVOID lpmsgbuf; 011 FormatMessage( 012 FORMAT_MESSAGE_ALLOCATE_BUFFER 013 FORMAT_MESSAGE_FROM_SYSTEM, 014 NULL, WSAGetLastError(), 015 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 016 (LPTSTR)&lpMsgBuf, 0, NULL); 017 MessageBox(NULL, (LPCTSTR)lpMsgBuf, msg, MB_ICONERROR); 018 LocalFree(lpMsgBuf); 019 exit(-1); 020 } 021 022 // 023 void err_display(char *msg) 024 { 025 LPVOID lpmsgbuf; 026 FormatMessage( 027 FORMAT_MESSAGE_ALLOCATE_BUFFER 028 FORMAT_MESSAGE_FROM_SYSTEM, 029 NULL, WSAGetLastError(), 030 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 031 (LPTSTR)&lpMsgBuf, 0, NULL); 032 printf("[%s] %s", msg, (LPCTSTR)lpMsgBuf); 033 LocalFree(lpMsgBuf); 034 } 035 036 // 037 int recvn(socket s, char *buf, int len, int flags) 038 { 039 int received; 040 char *ptr = buf; 041 int left = len; 042 043 while(left > 0){ 044 received = recv(s, ptr, left, flags); 045 if(received == SOCKET_ERROR) 046 return SOCKET_ERROR; 047 else if(received == 0) 048 break; 132 133

049 left -= received; 050 ptr += received; 051 } 052 053 return (len - left); 054 } 055 056 int main(int argc, char* argv[]) 057 { 058 int retval; 059 060 // 061 WSADATA wsa; 062 if(wsastartup(makeword(2,2), &wsa)!= 0) 063 return -1; 064 065 // socket() 066 SOCKET listen_sock = socket(af_inet, SOCK_STREAM, 0); 067 if(listen_sock == INVALID_SOCKET) err_quit("socket()"); 068 069 // bind() 070 SOCKADDR_IN serveraddr; 071 ZeroMemory(&serveraddr, sizeof(serveraddr)); 072 serveraddr.sin_family = AF_INET; 073 serveraddr.sin_port = htons(9000); 074 serveraddr.sin_addr.s_addr = htonl(inaddr_any); 075 retval = bind(listen_sock, (SOCKADDR *)&serveraddr, sizeof(serveraddr)); 076 if(retval == SOCKET_ERROR) err_quit("bind()"); 077 078 // listen() 079 retval = listen(listen_sock, SOMAXCONN); 080 if(retval == SOCKET_ERROR) err_quit("listen()"); 081 082 // 083 SOCKET client_sock; 084 SOCKADDR_IN clientaddr; 085 int addrlen; 086 char buf[bufsize]; 087 088 while(1){ 089 // accept() 090 addrlen = sizeof(clientaddr); 091 client_sock = accept(listen_sock, (SOCKADDR *)&clientaddr, &addrlen); 092 if(client_sock == INVALID_SOCKET){ 093 err_display("accept()"); 094 continue; 095 } 096 printf("\nfilesender : IP =%s, =%d\n", 097 inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port)); 098 099 // 100 char filename[256]; 101 ZeroMemory(filename, 256); 102 retval = recvn(client_sock, filename, 256, 0); 103 if(retval == SOCKET_ERROR){ 104 err_display("recv()"); 105 closesocket(client_sock); 106 continue; 107 } 108 printf("-> : %s\n", filename); 109 110 // 111 int totalbytes; 112 retval = recvn(client_sock, (char *)&totalbytes, sizeof(totalbytes), 0); 113 if(retval == SOCKET_ERROR){ 114 err_display("recv()"); 134 135

115 closesocket(client_sock); 116 continue; 117 } 118 printf("-> : %d\n", totalbytes); 119 120 // 121 FILE *fp = fopen(filename, "wb"); 122 if(fp == NULL){ 123 perror(" "); 124 closesocket(client_sock); 125 continue; 126 } 127 128 // 129 int numtotal = 0; 130 while(1){ 131 retval = recvn(client_sock, buf, BUFSIZE, 0); 132 if(retval == SOCKET_ERROR){ 133 err_display("recv()"); 134 break; 135 } 136 else if(retval == 0) 137 break; 138 else{ 139 fwrite(buf, 1, retval, fp); 140 if(ferror(fp)){ 141 perror(" "); 142 break; 143 } 144 numtotal += retval; 145 } 146 } 147 fclose(fp); 148 149 // 150 if(numtotal == totalbytes) 151 printf("->!\n"); 152 else 153 printf("->!\n"); 154 155 // closesocket() 156 closesocket(client_sock); 157 printf("filesender : IP =%s, =%d\n", 158 inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port)); 159 } 160 161 // closesocket() 162 closesocket(listen_sock); 163 164 // 165 WSACleanup(); 166 return 0; 167 } 136 137

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