在C ++中，獲取本地計算機的IP地址和子網(wǎng)掩碼的最簡單方法是什么？我希望能夠在本地網(wǎng)絡中檢測本地計算機的IP地址。在我的特定情況下，我的子網(wǎng)掩碼為255.255.255.0，計算機的IP地址為192.168.0.5。我需要以編程方式使它們具有兩個值，以便將廣播消息發(fā)送到我的網(wǎng)絡（對于我的特殊情況，格式為192.168.0.255）編輯：許多答案沒有給出我期望的結果，因為我有兩個不同的網(wǎng)絡IP。Torial的代碼成功了（它給了我兩個IP地址）。謝謝。
3 回答
一只斗牛犬
TA貢獻1784條經驗 獲得超2個贊
所有基于gethostbyname的方法的問題在于，您不會獲得分配給特定計算機的所有IP地址。服務器通常具有多個適配器。
這是一個如何遍歷主機上所有Ipv4和Ipv6地址的示例：
void ListIpAddresses(IpAddresses& ipAddrs)
{
IP_ADAPTER_ADDRESSES* adapter_addresses(NULL);
IP_ADAPTER_ADDRESSES* adapter(NULL);
// Start with a 16 KB buffer and resize if needed -
// multiple attempts in case interfaces change while
// we are in the middle of querying them.
DWORD adapter_addresses_buffer_size = 16 * KB;
for (int attempts = 0; attempts != 3; ++attempts)
{
adapter_addresses = (IP_ADAPTER_ADDRESSES*)malloc(adapter_addresses_buffer_size);
assert(adapter_addresses);
DWORD error = ::GetAdaptersAddresses(
AF_UNSPEC,
GAA_FLAG_SKIP_ANYCAST |
GAA_FLAG_SKIP_MULTICAST |
GAA_FLAG_SKIP_DNS_SERVER |
GAA_FLAG_SKIP_FRIENDLY_NAME,
NULL,
adapter_addresses,
&adapter_addresses_buffer_size);
if (ERROR_SUCCESS == error)
{
// We're done here, people!
break;
}
else if (ERROR_BUFFER_OVERFLOW == error)
{
// Try again with the new size
free(adapter_addresses);
adapter_addresses = NULL;
continue;
}
else
{
// Unexpected error code - log and throw
free(adapter_addresses);
adapter_addresses = NULL;
// @todo
LOG_AND_THROW_HERE();
}
}
// Iterate through all of the adapters
for (adapter = adapter_addresses; NULL != adapter; adapter = adapter->Next)
{
// Skip loopback adapters
if (IF_TYPE_SOFTWARE_LOOPBACK == adapter->IfType)
{
continue;
}
// Parse all IPv4 and IPv6 addresses
for (
IP_ADAPTER_UNICAST_ADDRESS* address = adapter->FirstUnicastAddress;
NULL != address;
address = address->Next)
{
auto family = address->Address.lpSockaddr->sa_family;
if (AF_INET == family)
{
// IPv4
SOCKADDR_IN* ipv4 = reinterpret_cast<SOCKADDR_IN*>(address->Address.lpSockaddr);
char str_buffer[INET_ADDRSTRLEN] = {0};
inet_ntop(AF_INET, &(ipv4->sin_addr), str_buffer, INET_ADDRSTRLEN);
ipAddrs.mIpv4.push_back(str_buffer);
}
else if (AF_INET6 == family)
{
// IPv6
SOCKADDR_IN6* ipv6 = reinterpret_cast<SOCKADDR_IN6*>(address->Address.lpSockaddr);
char str_buffer[INET6_ADDRSTRLEN] = {0};
inet_ntop(AF_INET6, &(ipv6->sin6_addr), str_buffer, INET6_ADDRSTRLEN);
std::string ipv6_str(str_buffer);
// Detect and skip non-external addresses
bool is_link_local(false);
bool is_special_use(false);
if (0 == ipv6_str.find("fe"))
{
char c = ipv6_str[2];
if (c == '8' || c == '9' || c == 'a' || c == 'b')
{
is_link_local = true;
}
}
else if (0 == ipv6_str.find("2001:0:"))
{
is_special_use = true;
}
if (! (is_link_local || is_special_use))
{
ipAddrs.mIpv6.push_back(ipv6_str);
}
}
else
{
// Skip all other types of addresses
continue;
}
}
}
// Cleanup
free(adapter_addresses);
adapter_addresses = NULL;
// Cheers!
}
喵喔喔
TA貢獻1735條經驗 獲得超5個贊
您可以使用gethostname后跟gethostbyname來獲取本地接口內部IP。
該返回的IP可能與您的外部IP不同。要獲取外部IP，您必須與外部服務器通信，該服務器將告訴您外部IP是什么。因為外部IP不是您的，而是您的路由器。
//Example: b1 == 192, b2 == 168, b3 == 0, b4 == 100
struct IPv4
{
unsigned char b1, b2, b3, b4;
};
bool getMyIP(IPv4 & myIP)
{
char szBuffer[1024];
#ifdef WIN32
WSADATA wsaData;
WORD wVersionRequested = MAKEWORD(2, 0);
if(::WSAStartup(wVersionRequested, &wsaData) != 0)
return false;
#endif
if(gethostname(szBuffer, sizeof(szBuffer)) == SOCKET_ERROR)
{
#ifdef WIN32
WSACleanup();
#endif
return false;
}
struct hostent *host = gethostbyname(szBuffer);
if(host == NULL)
{
#ifdef WIN32
WSACleanup();
#endif
return false;
}
//Obtain the computer's IP
myIP.b1 = ((struct in_addr *)(host->h_addr))->S_un.S_un_b.s_b1;
myIP.b2 = ((struct in_addr *)(host->h_addr))->S_un.S_un_b.s_b2;
myIP.b3 = ((struct in_addr *)(host->h_addr))->S_un.S_un_b.s_b3;
myIP.b4 = ((struct in_addr *)(host->h_addr))->S_un.S_un_b.s_b4;
#ifdef WIN32
WSACleanup();
#endif
return true;
}
您也可以始終只使用127.0.0.1，它始終代表本地計算機。
Windows中的子網(wǎng)掩碼：
您可以通過查詢以下注冊表項的子項來獲取子網(wǎng)掩碼（以及網(wǎng)關和其他信息）：
HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Tcpip \ Parameters \ Interfaces
查找注冊表值SubnetMask。
在Windows中獲取接口信息的其他方法：
您還可以通過以下方式檢索所需的信息： WSAIoctl，帶有以下選項：SIO_GET_INTERFACE_LIST
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