Linux網路編程（一）：一個簡單的socket程式

伺服器：

 1 /*
 2  *tcp_server.c
 3  */
 4 
 5 #include <stdio.h>
 6 #include <sys/socket.h>
 7 #include <netinet/in.h>
 8 #include <arpa/inet.h>
 9 #include <string.h>
10 #include <errno.h>
11 #include <stdlib.h>
12 #include <signal.h>
13 
14 #define SER_PORT 8000
15 #define MAX_LINE 1024
16 
17 void str_echo(int sockfd);
18 void sig_chld(int signo);
19 
20 int main(int argc, char **argv)
21 {
22     int listenfd, connfd;
23     struct sockaddr_in servaddr, cliaddr;
24     socklen_t cliaddr_len;
25     char buff[MAX_LINE];
26     pid_t childpid;
27     
28     listenfd = socket(AF_INET, SOCK_STREAM, 0);
29     
30     bzero(&servaddr, sizeof(servaddr));
31     servaddr.sin_family = AF_INET;
32     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
33     servaddr.sin_port = htons(SER_PORT);
34     
35     bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
36     
37     listen(listenfd, 20);
38     signal(SIGCHLD, sig_chld);
39     
40     while(1)
41     {
42         cliaddr_len = sizeof(cliaddr);
43         connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len);
44         printf("receive from %s at port %d\n", inet_ntop(AF_INET, &cliaddr.sin_addr, buff, sizeof(buff)), ntohs(cliaddr.sin_port));
45         
46         if ((childpid = fork()) == 0) /* child process */
47         {
48             printf("child process pid = %d\n", (int)childpid);
49             close(listenfd);
50             str_echo(connfd);
51             printf("child process terminated\n");
52             exit(0);
53         }
54         
55         close(connfd);
56     }
57 
58     return 0;
59 }
60 
61 void str_echo(int sockfd)
62 {
63     ssize_t n;
64     char buf[MAX_LINE] = {0};
65 
66 AGAIN:
67     while ((n = read(sockfd, buf, MAX_LINE)) > 0)
68     {
69         printf("%s\n", buf);
70         write(sockfd, buf, n);
71         bzero(buf, sizeof(buf));
72     }
73     
74     if (n < 0 && errno == EINTR)
75     {
76         goto AGAIN;
77     }
78     else if (n < 0)
79     {
80         printf("read error\n");
81     }
82     else
83     {
84         printf("str_echo: read EOF\n");
85     }
86     
87 }
88 
89 void sig_chld(int signo)
90 {
91     pid_t pid;
92     int stat;
93     
94     pid = wait(&stat);
95     printf("child %d terminated\n", pid);
96     
97     return;
98 }

客戶端：

 1 /*
 2  *tcp_client.c
 3  */
 4 
 5 #include <stdio.h>
 6 #include <sys/socket.h>
 7 #include <netinet/in.h>
 8 #include <arpa/inet.h>
 9 #include <errno.h>
10 #include <string.h>
11 
12 #define SER_PORT 8000
13 #define MAX_LINE 1024
14 
15 void str_cli(FILE *fp, int sockfd);
16 
17 int main(int argc, char **argv)
18 {
19     int sockfd;
20     struct sockaddr_in servaddr;
21 
22     sockfd = socket(AF_INET, SOCK_STREAM, 0);
23 
24     bzero(&servaddr, sizeof(servaddr));
25     servaddr.sin_family = AF_INET;
26     inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr);
27     servaddr.sin_port = htons(SER_PORT);
28     
29     if(connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0)
30     {
31         printf("connect error:%s\n", strerror(errno));
32         return 0;
33     }
34     
35     str_cli(stdin, sockfd);
36     
37     return 0;
38 }
39 
40 void str_cli(FILE *fp, int sockfd)
41 {
42     char sendline[MAX_LINE] = {0};
43     char recvline[MAX_LINE] = {0};
44 
45         
46     while (fgets(sendline, MAX_LINE, fp) != NULL)
47     {
48         write(sockfd, sendline, strlen(sendline));
49         
50         if (read(sockfd, recvline, MAX_LINE) == 0)
51         {
52             printf("server terminated\n");
53             break;
54         }
55         fputs(recvline, stdout);
56         
57         bzero(sendline, sizeof(sendline));
58         bzero(recvline, sizeof(recvline));
59     }
60 }

參考：

《UNIX網路編程 - 捲1：套接字聯網API》