模拟路由功能

server.c#include<stdio.h>#include<sys/socket.h>#include<sys/types.h>#include<netinet/in.h>#include<netdb.h>#include<stdlib.h>#include<string.h>#define PORT 8000int main(){struct sockaddr_in sin;struct sockaddr_in pin;int sock_main,tmp_socket,add_size;char buf[16384];int i;char str[]={"hello baby~"};if((sock_main=socket(AF_INET,SOCK_STREAM,0))==-1){perror("Failed socket");exit(1);}bzero(&sin,sizeof(sin));sin.sin_family=AF_INET;sin.sin_addr.s_addr=INADDR_ANY;sin.sin_port=htons(PORT);if(bind(sock_main,(struct sockaddr*)&sin,sizeof(sin))==-1){perror("failed bind");exit(1);}if(listen(sock_main,10)==-1){perror("failed listen");exit(1);}printf("start to wait accept connections..../n");tmp_socket=accept(sock_main,(struct sockaddr*)&pin,&add_size);if(tmp_socket==-1){perror("failed accept");exit(1);}if(send(tmp_socket,str,strlen(str)+1,0)==-1){perror("failed send");exit(1);}if(recv(tmp_socket,buf,16384,0)==-1){perror("failed recv");exit(1);}printf("received from client:/n%s/n",buf);close(tmp_socket);close(sock_main);exit(0);}  switch.c#include<stdio.h>#include<sys/socket.h>#include<netinet/in.h>#include<netdb.h>#include<string.h>#include<stdlib.h>#include<arpa/inet.h>#define HOST_NAME "192.168.157.28"#define BUF_SIZE 4096int main(int argc ,char *argv[]){int socket_s,socket_s1,tmp_socket,add_size;struct sockaddr_in pin1;struct sockaddr_in sin;struct sockaddr_in pin;struct hostent *s_host_info;char buf[8192];if((s_host_info=gethostbyname(HOST_NAME))==0){perror("failed gethostname/n");exit(1);}bzero(&pin1,sizeof(pin1));//用于和serverpin1.sin_family=AF_INET;pin1.sin_addr.s_addr=((struct in_addr*)(s_host_info->h_addr))->s_addr;pin1.sin_port=htons(8000);bzero(&pin,sizeof(pin));//用于和clientpin.sin_family=AF_INET;pin.sin_addr.s_addr=inet_addr("192.168.157.28");pin.sin_port=htons(8002);if((socket_s=socket(AF_INET,SOCK_STREAM,0))==-1) //socket_s{perror("failed connect");exit(1);}if(connect(socket_s,(void*)&pin1,sizeof(pin1))==-1){perror("failed connect");exit(1);}if(recv(socket_s,buf,BUF_SIZE,0)==-1)//接受server发来的消息，存放在buf里{perror("failed recv");exit(1);}printf("Response form server:/n%s/n",buf);if((socket_s1=socket(AF_INET,SOCK_STREAM,0))==-1)//socket_s1{perror("failed socket_s1");exit(1);}if(bind(socket_s1,(struct sockaddr*)&pin,sizeof(pin))==-1){perror("failed bind");exit(1);}if(listen(socket_s1,10)==-1){perror("failed listen");exit(1);}tmp_socket=accept(socket_s1,(struct sockaddr*)&pin,&add_size); // 接受client的请求if(tmp_socket==-1){perror("failed accept");exit(1);}if(send(tmp_socket,buf,strlen(buf)+1,0)==-1) //发送buf里的数据给client{perror("failed send/n");exit(1);}bzero(&buf,sizeof(buf));if(recv(tmp_socket,buf,BUF_SIZE,0)==-1){perror("failed recv");exit(1);}printf("received from client:/n%s/n",buf);if(send(socket_s,buf,strlen(buf)+1,0)==-1){perror("failed send/n");exit(1);}}  client.c#include<stdio.h>#include<sys/socket.h>#include<netinet/in.h>#include<arpa/inet.h>#include<netdb.h>#include<string.h>#include<stdlib.h>#define HOST_NAME "192.168.157.28"#define PORT 8002#define BUF_SIZE 4096int main(int argc,char *argv[]){int socket_descriptor;struct sockaddr_in pin;struct hostent *s_host_info;char buf[8192];char str[]={"hello,this is a test"};if((s_host_info=gethostbyname(HOST_NAME))==0){perror("failed gethostbyname/n");exit(1);}bzero(&pin,sizeof(pin));pin.sin_family=AF_INET;pin.sin_addr.s_addr=((struct in_addr *)(s_host_info->h_addr))->s_addr;pin.sin_port=htons(PORT);if((socket_descriptor=socket(AF_INET,SOCK_STREAM,0))==-1){perror("failed socket");exit(1);}if(connect(socket_descriptor,(void*)&pin,sizeof(pin))==-1){perror("failed connect");exit(1);}printf("sucessful connect with local host/n");if(send(socket_descriptor,str,strlen(str)+1,0)==-1){perror("failed send/n");exit(1);}printf("successful send the message to the server/n");if(recv(socket_descriptor,buf,BUF_SIZE,0)==-1){perror("failed recv");exit(1);}printf("/nResponse form server:/n/n%s/n",buf);close(socket_descriptor);return 0;}