我有一个运行网络服务器的wifi传感器模块（SN8200 EVK）。 该板配置为作为STA工作并自动加入WiFi路由器。 传感器板使用Hostname：“sensor”和DHCP接口来获取其IP地址。
我正在开发一个可视化工作室C＃应用程序来连接到这个网络服务器。 该应用程序在连接到同一WiFi路由器的笔记本电脑上运行。
传感器板＆lt; -----＆gt; WiFi路由器＆lt; -----＆gt;膝上型
如果我使用电路板IP地址，应用程序可以连接到传感器板。 由于IP地址不是静态的，我想使用主机名来检索IP。
我尝试使用GetHostEntry但得到了一个未知的主机结果。
IPHostEntry host;
host = Dns.GetHostEntry("sensor");
奇怪的是，如果我使用带有IP地址的GetHostEntry，它也无法解析主机名。
如果我尝试使用笔记本电脑的主机名或IP，GetHostEntry可以正常工作。 看起来GetHostEntry无法解析路由器后面的主机名。
欢迎任何帮助， 感谢。
答案 0 :(得分：0)
第一：
在您的Wifi路由器中配置DHCP服务器内的固定IP地址 PS：我很确定Mac地址不是动态的
第二：
使用先前修复的IP地址在DNS服务器中添加主机名。
在使用以下代码之前，您必须ping传感器板可以使用的所有IP，以刷新ARP缓存。
using System;
using System.Runtime.InteropServices;
using System.ComponentModel;
using System.Net;
using System.Collections.Generic;
namespace GetIpNetTable
{
class Program
{
static void Main(string[] args)
{
string[] ips = searchIpsFromMac("ff-ff-ff-ff-ff-ff");
if (ips.Length != 0)
{
foreach (string ip in ips)
{
// TODO - Do what you want with your IP address
Console.WriteLine(ip);
}
}
Console.ReadKey();
}
// The max number of physical addresses.
const int MAXLEN_PHYSADDR = 8;
// Define the MIB_IPNETROW structure.
[StructLayout(LayoutKind.Sequential)]
struct MIB_IPNETROW
{
[MarshalAs(UnmanagedType.U4)]
public int dwIndex;
[MarshalAs(UnmanagedType.U4)]
public int dwPhysAddrLen;
[MarshalAs(UnmanagedType.U1)]
public byte mac0;
[MarshalAs(UnmanagedType.U1)]
public byte mac1;
[MarshalAs(UnmanagedType.U1)]
public byte mac2;
[MarshalAs(UnmanagedType.U1)]
public byte mac3;
[MarshalAs(UnmanagedType.U1)]
public byte mac4;
[MarshalAs(UnmanagedType.U1)]
public byte mac5;
[MarshalAs(UnmanagedType.U1)]
public byte mac6;
[MarshalAs(UnmanagedType.U1)]
public byte mac7;
[MarshalAs(UnmanagedType.U4)]
public int dwAddr;
[MarshalAs(UnmanagedType.U4)]
public int dwType;
}
// Declare the GetIpNetTable function.
[DllImport("IpHlpApi.dll")]
[return: MarshalAs(UnmanagedType.U4)]
static extern int GetIpNetTable(
IntPtr pIpNetTable,
[MarshalAs(UnmanagedType.U4)]
ref int pdwSize,
bool bOrder);
[DllImport("IpHlpApi.dll", SetLastError = true, CharSet = CharSet.Auto)]
internal static extern int FreeMibTable(IntPtr plpNetTable);
// The insufficient buffer error.
const int ERROR_INSUFFICIENT_BUFFER = 122;
static string[] searchIpsFromMac(string macSearched)
{
List<string> ips = new List<string>(1);
// The number of bytes needed.
int bytesNeeded = 0;
// The result from the API call.
int result = GetIpNetTable(IntPtr.Zero, ref bytesNeeded, false);
// Call the function, expecting an insufficient buffer.
if (result != ERROR_INSUFFICIENT_BUFFER)
{
// Throw an exception.
throw new Win32Exception(result);
}
// Allocate the memory, do it in a try/finally block, to ensure
// that it is released.
IntPtr buffer = IntPtr.Zero;
// Try/finally.
try
{
// Allocate the memory.
buffer = Marshal.AllocCoTaskMem(bytesNeeded);
// Make the call again. If it did not succeed, then
// raise an error.
result = GetIpNetTable(buffer, ref bytesNeeded, false);
// If the result is not 0 (no error), then throw an exception.
if (result != 0)
{
// Throw an exception.
throw new Win32Exception(result);
}
// Now we have the buffer, we have to marshal it. We can read
// the first 4 bytes to get the length of the buffer.
int entries = Marshal.ReadInt32(buffer);
// Increment the memory pointer by the size of the int.
IntPtr currentBuffer = new IntPtr(buffer.ToInt64() +
Marshal.SizeOf(typeof(int)));
// Allocate an array of entries.
MIB_IPNETROW[] table = new MIB_IPNETROW[entries];
// Cycle through the entries.
for (int index = 0; index < entries; index++)
{
// Call PtrToStructure, getting the structure information.
table[index] = (MIB_IPNETROW)Marshal.PtrToStructure(new
IntPtr(currentBuffer.ToInt64() + (index *
Marshal.SizeOf(typeof(MIB_IPNETROW)))), typeof(MIB_IPNETROW));
}
for (int index = 0; index < entries; index++)
{
MIB_IPNETROW row = table[index];
IPAddress ip = new IPAddress(BitConverter.GetBytes(row.dwAddr));
string macAddr = row.mac0.ToString("X2") + '-' +
row.mac1.ToString("X2") + '-' +
row.mac2.ToString("X2") + '-' +
row.mac3.ToString("X2") + '-' +
row.mac4.ToString("X2") + '-' +
row.mac5.ToString("X2");
if (macAddr.ToUpper() == macSearched.ToUpper())
{
ips.Add(ip.ToString());
}
}
}
finally
{
// Release the memory.
FreeMibTable(buffer);
}
return ips.ToArray();
}
}
}