P2P_TCP.rar_P2P协议与TCP_TCP 透传_tcp协议_内网透传

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/socket.h> #include <sys/types.h> #include <arpa/inet.h> #define SER "192.168.0.118" #define PORT 8888 typedef struct { struct in_addr ip; int port; }IP; //ip与端口 typedef struct sockaddr SA; typedef struct sockaddr_in SA_IN; //回射服务 void echo_ser(int sockfd) { char buf[1024]; while(1) { bzero(buf,sizeof(buf)); //接收B发来的数据 recv(sockfd,buf,sizeof(buf)-1,0); printf("%s",buf); //向B发送数据 send(sockfd,buf,strlen(buf),0); buf[strlen(buf)-1]='\0'; if(strcmp(buf,"exit") == 0) break; } } int main(int argc,char **argv) { int sockfd,sockfd2; SA_IN server,addr; IP ip; socklen_t addrlen=sizeof(SA_IN); char s='a'; int flags=1; sockfd=socket(AF_INET,SOCK_STREAM,0); bzero(&server,sizeof(SA_IN)); server.sin_family=AF_INET; server.sin_addr.s_addr=inet_addr(SER); server.sin_port=htons(PORT); if(setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&flags,sizeof(int)) == -1) perror("setsockopt sockfd"); connect(sockfd,(SA *)&server,sizeof(SA_IN)); send(sockfd,&s,sizeof(char),0); recv(sockfd,&ip,sizeof(IP),0); close(sockfd); sockfd2=socket(AF_INET,SOCK_STREAM,0); if(sockfd2 == -1) perror("sockfd2"); if(setsockopt(sockfd2,SOL_SOCKET,SO_REUSEADDR,&flags,sizeof(int)) == -1) perror("setsockopt sockfd2"); server.sin_addr.s_addr=INADDR_ANY; server.sin_port=ip.port; if(bind(sockfd2,(SA *)&server,sizeof(SA_IN)) == -1) perror("bind sockfd"); if(listen(sockfd2,20) == -1) perror("listen"); echo_ser(accept(sockfd2,(SA *)&addr,&addrlen)); close(sockfd2); return 0; }