TCP回射服务器/客户端分析

 1 #include <unistd.h>
 2 #include <sys/types.h>
 3 #include <sys/socket.h>
 4 #include <arpa/inet.h>
 5 #include <netinet/in.h>
 6 
 7 #include <stdio.h>
 8 #include <stdlib.h>
 9 #include <string.h>
10 
11 #define ERR_EXIT(exp) 12     do13     {14         perror(exp);15         exit(EXIT_FAILURE);16     }while(0)
17 
18 #define BUFSIZE 1024
19 
20 int main(int argc, char *argv[])
21 {
22     if(argc != 2)
23         ERR_EXIT("Usage: a.out <port>");
24 
25     int server_sock;
26     int client_sock;
27     struct sockaddr_in server_addr;
28     struct sockaddr_in client_addr;
29     socklen_t server_len;
30     socklen_t client_len;
31 
32     server_sock = socket(PF_INET, SOCK_STREAM, 0);
33     if(server_sock == -1)
34         ERR_EXIT("socket");
35 
36     memset(&server_addr, 0, sizeof(server_addr));
37     server_addr.sin_family = AF_INET;
38     server_addr.sin_addr.s_addr = INADDR_ANY;
39     server_addr.sin_port = htons(atoi(argv[1]));
40     server_len = sizeof(server_addr);
41     client_len = sizeof(client_addr);
42 
43     if(bind(server_sock, (struct sockaddr*)&server_addr, server_len) == -1)
44         ERR_EXIT("bind");
45 
46     if(listen(server_sock, 5) == -1)
47         ERR_EXIT("listen");
48 
49     client_sock = accept(server_sock, (struct sockaddr*)&client_addr, &client_len);
50     if(client_sock == -1)
51         ERR_EXIT("accept");
52     char buffer[BUFSIZE];
53     read(client_sock, buffer, BUFSIZE);
54     write(client_sock, buffer, strlen(buffer));
55 
56     sleep(3);
57     close(client_sock);
58     close(server_sock);
59     return 0;
60 }

 1 #include <unistd.h>
 2 #include <sys/types.h>
 3 #include <sys/socket.h>
 4 #include <arpa/inet.h>
 5 #include <netinet/in.h>
 6 
 7 #include <stdio.h>
 8 #include <stdlib.h>
 9 #include <string.h>
10 
11 #define ERR_EXIT(exp) 12     do13     {14         perror(exp);15         exit(EXIT_FAILURE);16     }while(0)
17 
18 #define BUFSIZE 1024
19 
20 int main(int argc, char *argv[])
21 {
22     if(argc != 3)
23         ERR_EXIT("Usage: a.out <server_ip> <port>");
24 
25     int server_sock;
26     struct sockaddr_in server_addr;
27     socklen_t server_len;
28 
29     server_sock = socket(PF_INET, SOCK_STREAM, 0);
30     if(server_sock == -1)
31         ERR_EXIT("socket");
32 
33     server_addr.sin_family = AF_INET;
34     server_addr.sin_addr.s_addr = inet_addr(argv[1]);
35     server_addr.sin_port = htons(atoi(argv[2]));
36     server_len = sizeof(server_addr);
37 
38     if(connect(server_sock, (struct sockaddr*)&server_addr, server_len) == -1)
39         ERR_EXIT("connect");
40 
41     char buffer[BUFSIZE] = "Hello World!";
42     write(server_sock, buffer, strlen(buffer));
43     memset(buffer, 0, BUFSIZE);
44     read(server_sock, buffer, BUFSIZE);
45     printf("%s\n", buffer);
46 
47     sleep(1);
48     close(server_sock);
49     return 0;
50 }