系统：fedora core 5
服务器端程序：
/* server */
#include <stdio.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#define PORT 8848
#define BACKLOG 1
main()
{
int listenfd,connectfd;
struct sockaddr_in server;
struct sockaddr_in client;
int sin_size;
if (( listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
perror("Creating socket failed.");
return 0;
}
int opt = SO_REUSEADDR;
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
bzero(&server,sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT);
server.sin_addr.s_addr = htonl(INADDR_ANY);
printf("binding... ");
if(bind(listenfd, (struct sockaddr *)&server, sizeof(struct sockaddr)) == -1) {
perror("Bind error");
return 0;
}
printf("listen... ");
if(listen(listenfd,BACKLOG) == -1){
perror("listen() error ");
return 0;
}
printf("accept.... ");
sin_size = sizeof(struct sockaddr_in);
if ((connectfd = accept(listenfd, (struct sockaddr *)&client,(socklen_t *) &sin_size)) == -1) {
perror("accept() error ");
return 0;
}
printf("you got a connection from %s ",inet_ntoa(client.sin_addr) );
send(connectfd,"welcome to my server. ",22,0);
close(connectfd);
close(listenfd);
}
客户端程序：
/* client */
#include <stdio.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <errno.h>
#define PORT 8848
#define MAXDATASIZE 100
int main(int argc, char *argv[])
{
int fd, numbytes;
char buf[MAXDATASIZE];
struct hostent *he;
int errno;
struct sockaddr_in server;
if(argc != 2) {
printf("usage: %s <ip address> ",argv[0]);
return 0;
}
printf("gethostbynem.... ");
if ((he = gethostbyname(argv[1]))==NULL){
printf("gethostbyname() error ");
return 0;
}
if((fd=socket(AF_INET,SOCK_STREAM, 0)) == -1){
printf("socket() error ");
return 0;
}
bzero(&server,sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT);
server.sin_addr = *((in_addr*)he->h_addr);
printf("connecting... ");
if(connect(fd, (struct sockaddr *)&server,sizeof(struct sockaddr)) == -1){
// printf("connect() error ");
perror("error");
return 0;
}
if(( numbytes = recv(fd,buf,MAXDATASIZE,0)) == -1){
printf("recv() error ");
return 0;
}
buf[numbytes] = '
操作：
[root@localhost tcpsocket]# ls
help tcpsocketC.c tcpsocketS.c
[root@localhost tcpsocket]# g++ -g -o myserver tcpsocketS.c -lc -lnsl
[root@localhost tcpsocket]# g++ -g -o myclient tcpsocketC.c -lc -lnsl
[root@localhost tcpsocket]# ls
help myclient myserver tcpsocketC.c tcpsocketS.c
[root@localhost tcpsocket]# ./myserver
binding...
listen...
accept....
[root@localhost tcpsocket]# netstat -a | grep 8848
tcp 0 0 *:8848 *:* LISTEN
[root@localhost tcpsocket]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:13:D4:3E:9F:89
inet addr:125.221.160.241 Bcast:125.221.160.255 Mask:255.255.255.0
inet6 addr: fe80::213:d4ff:fe3e:9f89/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:39108 errors:0 dropped:0 overruns:0 frame:0
TX packets:46 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2359238 (2.2 MiB) TX bytes:4040 (3.9 KiB)
Interrupt:17 Base address:0xa000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:2005 errors:0 dropped:0 overruns:0 frame:0
TX packets:2005 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2078171 (1.9 MiB) TX bytes:2078171 (1.9 MiB)
[root@localhost tcpsocket]# ./myclient 127.0.0.1