一步一步學Linux C：Socket實例

客戶端：

1. #include <stdio.h>
2. #include <sys/socket.h>
3. #include <unistd.h>
4. #include <sys/types.h>
5. #include <netinet/in.h>
6. #include <stdlib.h>
9. #define SERVER_PORT 20000 // define the defualt connect port id
10. #define CLIENT_PORT ((20001+rand())%65536) // define the defualt client port as a random port
11. #define BUFFER_SIZE 255
12. #define REUQEST_MESSAGE "welcome to connect the server.\n"
15. void usage(char* name)
16. {
17. printf( " usage: %s IpAddr\n " ,name);
18. }
21. int main(int argc, char** argv)
22. {
23. int servfd,clifd,length = 0;
24. struct sockaddr_in servaddr,cliaddr;
25. socklen_t socklen = sizeof (servaddr);
26. char buf[BUFFER_SIZE];
28. if (argc < 2 )
29. {
30. usage(argv[ 0 ]);
31. exit( 1 );
32. }
34. if ((clifd = socket(AF_INET,SOCK_STREAM, 0 )) < 0 )
35. {
36. printf( " create socket error!\n " );
37. exit( 1 );
38. }
40. srand(time(NULL)); // initialize random generator
42. bzero( & cliaddr, sizeof (cliaddr));
43. cliaddr.sin_family = AF_INET;
44. cliaddr.sin_port = htons(CLIENT_PORT);
45. cliaddr.sin_addr.s_addr = htons(INADDR_ANY);
47. bzero( & servaddr, sizeof (servaddr));
48. servaddr.sin_family = AF_INET;
49. inet_aton(argv[ 1 ], & servaddr.sin_addr);
50. servaddr.sin_port = htons(SERVER_PORT);
51. // servaddr.sin_addr.s_addr = htons(INADDR_ANY);
53. if (bind(clifd, (struct sockaddr* ) &cliaddr, sizeof (cliaddr)) < 0 )
54. {
55. printf( " bind to port %d failure!\n " ,CLIENT_PORT);
56. exit( 1 );
57. }
59. if (connect(clifd,( struct sockaddr * ) & servaddr, socklen) < 0 )
60. {
61. printf( " can't connect to %s!\n ", argv[ 1 ]);
62. exit( 1 );
63. }
65. length = recv(clifd, buf, BUFFER_SIZE, 0);
66. if (length < 0)
67. {
68. printf( " error comes when recieve data from server %s! ", argv[1] );
69. exit( 1 );
70. }
72. printf( " from server %s :\n\t%s", argv[1], buf);
74. close(clifd);
75. return 0;
76. }

1. #include <stdio.h>
2. #include <sys/socket.h>
3. #include <unistd.h>
4. #include <sys/types.h>
5. #include <netinet/in.h>
6. #include <stdlib.h>
7. #include <time.h>
9. #define SERVER_PORT 20000 // define the defualt connect port id
10. #define LENGTH_OF_LISTEN_QUEUE 10 // length of listen queue in server
11. #define BUFFER_SIZE 255
12. #define WELCOME_MESSAGE "welcome to connect the server. "
14. int main(int argc, char** argv)
15. {
16. int servfd,clifd;
17. struct sockaddr_in servaddr,cliaddr;
19. if ((servfd = socket(AF_INET,SOCK_STREAM, 0 )) < 0 )
20. {
21. printf( " create socket error!\n " );
22. exit( 1 );
23. }
25. bzero( & servaddr, sizeof (servaddr));
27. servaddr.sin_family = AF_INET;
28. servaddr.sin_port = htons(SERVER_PORT);
29. servaddr.sin_addr.s_addr = htons(INADDR_ANY);
31. if (bind(servfd,( struct sockaddr * ) & servaddr, sizeof (servaddr)) < 0 )
32. {
33. printf( " bind to port %d failure!\n " ,SERVER_PORT);
34. exit( 1 );
35. }
37. if (listen(servfd,LENGTH_OF_LISTEN_QUEUE) < 0 )
38. {
39. printf( " call listen failure!\n " );
40. exit( 1 );
41. }
43. while ( 1 )
44. { // server loop will nerver exit unless any body kill the process
46. char buf[BUFFER_SIZE];
47. long timestamp;
48. socklen_t length = sizeof (cliaddr);
49. clifd = accept(servfd,( struct sockaddr * ) & cliaddr, & length);
51. if (clifd < 0 )
52. {
53. printf( " error comes when call accept!\n " );
54. break ;
55. }
57. strcpy(buf,WELCOME_MESSAGE);
59. // inet_ntop(INET_ADDRSTRLEN,cliaddr.sin_addr,buf,BUFFER_SIZE);
61. printf( " from client,IP:%s,Port:%d\n " ,inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.sin_port));
63. timestamp = time(NULL);
65. strcat(buf, " timestamp in server: " );
66. strcat(buf,ctime( & timestamp));
68. send(clifd,buf,BUFFER_SIZE, 0 );
70. close(clifd);
72. } // exit
74. close(servfd);
76. return 0 ;
77. }