#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;
}

gcc -o getip getip.c

./getip