可以在同一台电脑上运行，在一个终端上运行服务器端，在一个终端上运行客户端。
服务器端的IP地址要和本地的IP相同，并分配端口号，客户端的默认设置为本地，端口号自动分配。
服务器端：
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>
#include <arpa/inet.h>
#define MAXBUF 1024
int main(int argc, char *argv[])
{
int pid;
int sockfd, new_fd;
socklen_t len;
struct sockaddr_in my_addr, their_addr;
unsigned int myport, lisnum;
char buf[MAXBUF + 1];
if (argv[2])
myport = atoi(argv[2]);
else
myport = 7575;
if (argv[3])
lisnum = atoi(argv[3]);
else
lisnum = 5;
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
perror("socket");
exit(EXIT_FAILURE);
}
bzero(&my_addr, sizeof(my_addr));
my_addr.sin_family = AF_INET;
my_addr.sin_port = htons(myport);
if (argv[1])
my_addr.sin_addr.s_addr = inet_addr(argv[1]);
else
my_addr.sin_addr.s_addr = INADDR_ANY;
if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr))== -1)
{
perror("bind");
exit(EXIT_FAILURE);
}
if (listen(sockfd,lisnum ) == -1)
{
perror("listen");
exit(EXIT_FAILURE);
}
printf("wait for connect\n");
len = sizeof(struct sockaddr);
if ((new_fd =accept(sockfd, (struct sockaddr *) &their_addr,&len)) == -1)
{
perror("accept");
exit(EXIT_FAILURE);
}
else
printf("server: got connection from %s, port %d, socket %d\n",inet_ntoa(their_addr.sin_addr),ntohs(their_addr.sin_port), new_fd);
if(-1==(pid=fork()))
{
perror("fork");exit(EXIT_FAILURE);
}
else if( pid == 0)
{
while (1)
{
bzero(buf, MAXBUF + 1);
printf("input the message to send:");
fgets(buf, MAXBUF, stdin);
if (!strncasecmp(buf, "quit", 4))
{
printf("i will close the connect!\n");
break;
}
len = send(new_fd, buf, strlen(buf) - 1, 0);
if (len < 0)
{
printf("message'%s' send failure!errno code is %d,errno message is '%s'\n",
buf, errno, strerror(errno));
break;
}
}
}
else
{
while(1)
{
bzero(buf, MAXBUF + 1);
len = recv(new_fd, buf, MAXBUF, 0);
if (len > 0)
printf("message recv successful :'%s',%dByte recv\n",buf, len);
else if (len < 0)
{
printf("recv failure!errno code is %d,errno message is '%s'\n",
errno, strerror(errno));
break;
}
else
{
printf("the other one close quit\n");
break;
}
}
}
close(new_fd);
close(sockfd);
return 0;
}
客户端：
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <resolv.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#define MAXBUF 1024
int main(int argc, char **argv)
{
int sockfd, len;
struct sockaddr_in dest;
char buffer[MAXBUF + 1];
if (argc != 3)
{
printf(" error format,it must be:\n\t\t%s IP port\n",argv[0]);
exit(EXIT_FAILURE);
}
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror("Socket");
exit(errno);
}
printf("socket created\n");
bzero(&dest, sizeof(dest));
dest.sin_family = AF_INET;
dest.sin_port = htons(atoi(argv[2]));
if (inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr) == 0)
{
perror(argv[1]); exit(errno);
}
if (connect(sockfd, (struct sockaddr *) &dest, sizeof(dest))==-1)
{
perror("Connect ");
exit(errno);
}
printf("server connected\n");
pid_t pid;
if(-1==(pid=fork()))
{
perror("fork");exit(EXIT_FAILURE);
}
else if (pid==0)
{
while (1)
{
bzero(buffer, MAXBUF + 1);
len = recv(sockfd, buffer, MAXBUF, 0);
if (len > 0)
printf("recv successful:'%s',%d byte recv\n",buffer, len);
else if(len < 0)
{
perror("recv");
break;
}
else
{
printf("the other one close ,quit\n");
break;
}
}
}
else
{
while (1)
{
bzero(buffer, MAXBUF + 1);
printf("pls send message to send:");
fgets(buffer, MAXBUF, stdin);
if (!strncasecmp(buffer, "quit", 4))
{
printf(" i will quit!\n");
break;
}
len = send(sockfd, buffer, strlen(buffer) - 1, 0);
if (len < 0)
{
perror("send");
break;
}
}
}
close(sockfd);
return 0;
}
服务器端执行 ： ./s 192.168.142.132 7575 5
客户端执行： ./c 192.168.142.132 7575
其中，192.168.142.132是本机的IP地址.
服务器端信息：
[email protected]:/home/jieniyimiao/c_code/linux/ch13/sock_tcp_p_p_chat# ./s 192.168.142.132 7575 5
wait for connect
server: got connection from 192.168.142.132, port 44698, socket 4
input the message to send:jieniyimiap
input the message to send:ddddddddddddddddddddddddddd
input the message to send:dddddddddddddddddddddddddddd
input the message to send:aaaaaaaaaaaaaaaaaaaaaa
input the message to send:aaaaaaaaaaaaaaaaaaaaaaaa
input the message to send:message recv successful :‘dddddddddddddddddd‘,18Byte recv
message recv successful :‘ddddddddddddddddd‘,17Byte recv
message recv successful :‘ddddddddddddddddd‘,17Byte recv
message recv successful :‘dddddddddddddd‘,14Byte recv
message recv successful :‘ddddddddddddddd‘,15Byte recv
message recv successful :‘ddddddddddddddddd‘,17Byte recv
message recv successful :‘dddddddddddddd‘,14Byte recv
quit
i will close the connect!
客户端略：
用NETSTAT查看信息如下：
# netstat |grep 192.168.142.132
**********************************************************************************
tcp 0 0 192.168.142.132:7575 192.168.142.132:44698 ****
tcp 0 0 192.168.142.132:44698 192.168.142.132:7575 ****