vc根据域名获取IP地址 gethostbyname()函数
vc根据域名获取IP地址 gethostbyname()函数
以下是VC Socket初始化时用到的两个函数
一、WSAStartup函数
int WSAStartup
(
WORD wVersionRequested,
LPWSADATA lpWSAData
);
使用Socket的程序在使用Socket之前必须调用WSAStartup函数。该函数的第一个参数指明程序请求使用的Socket版本，其中高位字节指明副版本、低位字节指明主版本；操作系统利用第二个参数返回请求的Socket的版本信息。当一个应用程序调用WSAStartup函数时，操作系统根据请求的Socket版本来搜索相应的Socket库，然后绑定找到的Socket库到该应用程序中。以后应用程序就可以调用所请求的Socket库中的其它Socket函数了。该函数执行成功后返回0。
例：假如一个程序要使用2.1版本的Socket,那么程序代码如下
wVersionRequested = MAKEWORD( 2, 1 );
err = WSAStartup( wVersionRequested, &wsaData );
二、WSACleanup函数
int WSACleanup (void);
应用程序在完成对请求的Socket库的使用后，要调用WSACleanup函数来解除与Socket库的绑定并且释放Socket库所占用的系统资源。
三 Socket接口的检索有关域名、通信服务和协议等Internet信息的数据库函数，如
gethostbyaddr、gethostbyname、gethostname、getprotolbyname
getprotolbynumber、getserverbyname、getservbyport。
1．gethostname()
【函数原型】
int PASCAL FAR gethostname (char FAR * name, int namelen);
【使用说明】
该函数可以获取本地主机的主机名，其中：
name：<输出>用于指向所获取的主机名的缓冲区的指针。
Namelen：<输入>缓冲区的大小，以字节为单位。
返回值：若无错误，返回0；否则，返回错误代吗。
2．gethostbyname()
【函数原型】
struct hostent FAR * PASCAL FAR gethostbyname(const char FAR * name);
【使用说明】
该函数可以从主机名数据库中得到对应的“主机”。
该函数唯一的参数name就是前面调用函数gethostname()得到的主机名。若无错误，刚返回一个指向hostent结构的批针，它可以标识一个“主机”列表。
===============================================
根据域名 获取IP地址 gethostbyname()函数
可以运行的源代码
很容易, 但让一个没用过的人就不好写, 那些高手都很懒写BLOG
:
//getip.cpp
#include
#include
#include
#pragma comment(lib, "ws2_32")
using namespace std;
int main()
{
int WSA_return;
WSADATA WSAData;
WSA_return=WSAStartup(0x0101,&WSAData);
HOSTENT *host_entry;
char host_name[256] ="http://www.google.cn/";
if(WSA_return==0)
{
host_entry=gethostbyname(host_name);
printf("%s/n", host_name);
if(host_entry!=0)
{
printf("解析IP地址: ");
printf("%d.%d.%d.%d",
(host_entry->h_addr_list[0][0]&0x00ff),
(host_entry->h_addr_list[0][1]&0x00ff),
(host_entry->h_addr_list[0][2]&0x00ff),
(host_entry->h_addr_list[0][3]&0x00ff));
}
}
WSACleanup();
下面有几份不同功能的代码：
/*#include
#include
#include
#pragma comment(lib,"ws2_32.lib")
using namespace std;
void main()
{
WSADATA wsaData;
char szHostname[100]="baidu.com";
HOSTENT *pHostEnt;
int nAdapter = 0;
struct sockaddr_in sAddr;
if (WSAStartup(0x0101, &wsaData))
{
printf( "WSAStartup failed %s/n ", WSAGetLastError());
return;
}
pHostEnt = gethostbyname(szHostname);
while ( pHostEnt-> h_addr_list[nAdapter] )
{
// pHostEnt-> h_addr_list[nAdapter] is the current address in host
// order.
// Copy the address information from the pHostEnt to a sockaddr_in
// structure.
memcpy ( &sAddr.sin_addr.s_addr, pHostEnt-> h_addr_list[nAdapter],
pHostEnt-> h_length);
// Output the machines IP Address.
printf( "Name: %s/nAddress: %s/n ", pHostEnt-> h_name,
inet_ntoa(sAddr.sin_addr));
nAdapter++;
}
WSACleanup();
return;
}
*/
/*
#include
#include
#pragma comment(lib,"WS2_32.LIB")
void TestFunOne(void)
{
SOCKET m_socket=socket(AF_INET,SOCK_STREAM,0);
SOCKADDR_IN addr;
addr.sin_family=AF_INET;
addr.sin_port=htons(80);
addr.sin_addr.S_un.S_addr=inet_addr("202.108.22.5");
if(connect(m_socket,(SOCKADDR *)&addr,sizeof(SOCKADDR))!=SOCKET_ERROR)
{
printf("连接百度成功! TestFunOne../n");
}
else
{
printf("连接百度失败! TestFunOne../n");
}
closesocket(m_socket);
}
DWORD WINAPI TestThreadOne(LPVOID lparameter)
{
SOCKET m_socket=socket(AF_INET,SOCK_STREAM,0);
SOCKADDR_IN addr;
addr.sin_family=AF_INET;
addr.sin_port=htons(80);
addr.sin_addr.S_un.S_addr=inet_addr("202.108.22.5");
if(connect(m_socket,(SOCKADDR *)&addr,sizeof(SOCKADDR))!=SOCKET_ERROR)
{
printf("连接百度成功! thread one../n");
}
else
{
printf("连接百度失败! thread one../n");
}
closesocket(m_socket);
TestFunOne();
return 1;
}
int main(int argc, char* argv[])
{
WSAData wsa;
WSAStartup(MAKEWORD(2,2),&wsa);
CloseHandle(CreateThread(NULL,NULL,TestThreadOne,NULL,NULL,NULL));
SOCKET m_socket=socket(AF_INET,SOCK_STREAM,0);
SOCKADDR_IN addr;
addr.sin_family=AF_INET;
addr.sin_port=htons(80);
addr.sin_addr.S_un.S_addr=inet_addr("202.108.22.5");
if(connect(m_socket,(SOCKADDR *)&addr,sizeof(SOCKADDR))!=SOCKET_ERROR)
{
printf("连接百度成功! main thread../n");
}
else
{ againstvirus
printf("连接百度失败! main thread../n");
}
closesocket(m_socket);
WSACleanup();
Sleep(20000000);
return 0;
}
*/
#include
#include
#include
#include
#pragma comment(lib, "ws2_32.lib")
int main(int argc, char **argv)
{
//-----------------------------------------
// 定义初始化变量
WSADATA wsaData;
int iResult;
DWORD dwError;
int i = 0;
struct hostent *remoteHost;
char *host_name;
struct in_addr addr;
char **pAlias;
// 校验参数
if (argc != 2) {
printf("usage: %s ipv4address/n", argv[0]);
printf(" or/n");
printf(" %s hostname/n", argv[0]);
printf(" to return the host/n");
printf(" %s 127.0.0.1/n", argv[0]);
printf(" to return the IP addresses for a host/n");
printf(" %s www.a3gs.com/n", argv[0]);
return 1;
}
// 初始化Winsock
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed: %d/n", iResult);
return 1;
}
host_name = argv[1];
// 如果用户输入是一个字母, 则我们使用gethostbyname()函数
// 假如输入是数字，则判断为IP地址
if (isalpha(host_name[0])) {
printf("Calling gethostbyname with %s/n", host_name);
remoteHost = gethostbyname(host_name);
} else {
printf("使用%s调用gethostbyaddr函数%s/n", host_name);
addr.s_addr = inet_addr(host_name);
if (addr.s_addr == INADDR_NONE) {
printf("请输入有效IPv4地址/n");
return 1;
} else
{
remoteHost = gethostbyaddr((char *) &addr, 4, AF_INET);
}
}
if (remoteHost == NULL) {
dwError = WSAGetLastError();
if (dwError != 0) {
if (dwError == WSAHOST_NOT_FOUND) {
printf("无法定位到主机/n");
return 1;
}else if (dwError == WSANO_DATA) {
printf("无路由记录/n");
return 1;
} else {
printf("函数调用出错，代码: %ld/n", dwError);
return 1;
}
}
} else {
printf("函数返回:/n");
printf("/t主机名称: %s/n", remoteHost->h_name);
for (pAlias = remoteHost->h_aliases; *pAlias != 0; pAlias++) {
printf("/t主机别名#%d: %s/n", ++i, *pAlias);
}
printf("/t地址类型: ");
switch (remoteHost->h_addrtype) {
case AF_INET:
printf("AF_INET/n");
break;
case AF_INET6:
printf("AF_INET6/n");
break;
case AF_NETBIOS:
printf("AF_NETBIOS/n");
break;
default:
printf(" %d/n", remoteHost->h_addrtype);
break;
}
printf("/t地址长度: %d/n", remoteHost->h_length);
i = 0;
while (remoteHost->h_addr_list[i] != 0) {
addr.s_addr = *(u_long *) remoteHost->h_addr_list[i++];
printf("/t主机IP地址#%d: %s/n", i, inet_ntoa(addr));
}
}
return 0;
}
#include
#include
#include
#include
#include
#pragma comment(lib, "ws2_32.lib")
int main(int argc, char **argv)
{
//-----------------------------------------
// 定义初始化变量
WSADATA wsaData;
int iResult;
DWORD dwError;
int i = 0;
struct hostent *remoteHost;
char *host_name;
struct in_addr addr;
char **pAlias;
// 校验参数
if (argc != 2) {
printf("usage: %s ipv4address/n", argv[0]);
printf(" or/n");
printf(" %s hostname/n", argv[0]);
printf(" to return the host/n");
printf(" %s 127.0.0.1/n", argv[0]);
printf(" to return the IP addresses for a host/n");
printf(" %s www.a3gs.com/n", argv[0]);
return 1;
}
// 初始化Winsock
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed: %d/n", iResult);
return 1;
}
host_name = argv[1];
// 如果用户输入是一个字母, 则我们使用gethostbyname()函数
// 假如输入是数字，则判断为IP地址
if (isalpha(host_name[0])) {
printf("Calling gethostbyname with %s/n", host_name);
remoteHost = gethostbyname(host_name);
} else {
printf("使用%s调用gethostbyaddr函数%s/n", host_name);
addr.s_addr = inet_addr(host_name);
if (addr.s_addr == INADDR_NONE) {
printf("请输入有效IPv4地址/n");
return 1;
} else
{
remoteHost = gethostbyaddr((char *) &addr, 4, AF_INET);
}
}
if (remoteHost == NULL) {
dwError = WSAGetLastError();
if (dwError != 0) {
if (dwError == WSAHOST_NOT_FOUND) {
printf("无法定位到主机/n");
return 1;
}else if (dwError == WSANO_DATA) {
printf("无路由记录/n");
return 1;
} else {
printf("函数调用出错，代码: %ld/n", dwError);
return 1;
}
}
} else {
printf("函数返回:/n");
printf("/t主机名称: %s/n", remoteHost->h_name);
for (pAlias = remoteHost->h_aliases; *pAlias != 0; pAlias++) {
printf("/t主机别名#%d: %s/n", ++i, *pAlias);
}
printf("/t地址类型: ");
switch (remoteHost->h_addrtype) {
case AF_INET:
printf("AF_INET/n");
break;
case AF_INET6:
printf("AF_INET6/n");
break;
case AF_NETBIOS:
printf("AF_NETBIOS/n");
break;
default:
printf(" %d/n", remoteHost->h_addrtype);
break;
}
printf("/t地址长度: %d/n", remoteHost->h_length);
i = 0;
while (remoteHost->h_addr_list[i] != 0) {
addr.s_addr = *(u_long *) remoteHost->h_addr_list[i++];
printf("/t主机IP地址#%d: %s/n", i, inet_ntoa(addr));
}
}
return 0;
}