#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
typedef enum {false,true}bool;
int main()
{
bool flag;
int sock;
char **pptr = NULL;
struct sockaddr_in destAddr;
struct hostent *ptr = NULL;
char destIP[128];
char szBuffer[] = {"GET /ip2city.asp HTTP/1.1/r/nHost:www.ip138.com/r/nConnection:Close/r/n/r/n"};
char res[1024];
//初始化socket
sock = socket(AF_INET,SOCK_STREAM,0);
if( -1 == sock ){
perror("creat socket failed");
exit(0);
}
bzero((void *)&destAddr,sizeof(destAddr));
destAddr.sin_family = AF_INET;
destAddr.sin_port = htons(80);
//首先是獲取www.ip138.com的IP地址
ptr = gethostbyname("www.ip138.com");
if(NULL == ptr){
perror("gethostbyname error");
exit(0);
}
//對于www.ip138.com的每個IP進行嘗試連接，直到有一個連接成功為止，或者無法連接，則退出程序
for(flag=false,pptr=ptr->h_addr_list ; NULL != *pptr ; ++pptr){
inet_ntop(ptr->h_addrtype,*pptr,destIP,sizeof(destIP));
printf("addr:%s/n",destIP);
destAddr.sin_addr.s_addr = inet_addr(destIP);
if(-1!=connect(sock,(struct sockaddr *)&destAddr,sizeof(struct sockaddr))){
flag = true;
break;
}
}
if(false == flag){
perror("connect failed");
}
//發送獲取IP的數據包給www.ip138.com
if(strlen(szBuffer) != send(sock,szBuffer,strlen(szBuffer),0)){
perror("send error");
exit(0);
}
//接收數據包
if(-1 == recv(sock,res,1024,0)){
perror("recv error");
exit(0);
}
printf("res:/n%s/n",res);
return 0;
}
