/// <summary>
/// Removes a <see cref="DynDnsHostEntry" /> registration from the Dynamic
/// DNS cluster.
/// </summary>
/// <param name="hostEntry">The host/IP address <see cref="DynDnsHostEntry" /> to be unregistered.</param>
/// <remarks>
/// <note>
/// This method does not throw an exception if the registration is not present.
/// </note>
/// </remarks>
/// <exception cref="InvalidOperationException">Thrown if the client has not been started.</exception>
public void Unregister(DynDnsHostEntry hostEntry)
{
using (TimedLock.Lock(syncLock))
{
if (hosts.ContainsKey(hostEntry))
{
// For UDP mode, we need to send two immediate Unregister message to each DNS
// server for the host entry.
if (settings.Mode == DynDnsMode.Udp && isOpen)
{
for (int i = 0; i < 2; i++)
{
DynDnsMessage message;
byte[] packet;
message = new DynDnsMessage(DynDnsMessageFlag.OpUnregister, hostEntry);
packet = message.ToArray(settings.SharedKey);
foreach (var nameServer in settings.NameServers)
{
socket.SendTo(packet, nameServer);
}
}
}
// Remove the host entry from the local table.
hosts.Remove(hostEntry);
Register();
}
}
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="flags">Specifies the operation to be performed in addition to operation related options.</param>
/// <param name="hostEntry">The host entry information.</param>
public DynDnsMessage(DynDnsMessageFlag flags, DynDnsHostEntry hostEntry)
{
this.TimeStampUtc = DateTime.UtcNow;
this.Version = FormatVer;
this.Flags = flags;
this.HostEntry = hostEntry;
}
/// <summary>
/// Decrypts and deserializes a message from a byte buffer.
/// </summary>
/// <param name="buffer">The buffer.</param>
/// <param name="sharedKey">The shared encryption key.</param>
/// <exception cref="FormatException">Thrown if the buffer does not contain a valid message.</exception>
public DynDnsMessage(byte[] buffer, SymmetricKey sharedKey)
{
try
{
using (var ms = new EnhancedMemoryStream(Crypto.Decrypt(buffer, sharedKey)))
{
if (ms.ReadInt32Le() != Magic)
{
throw new Exception();
}
this.Version = ms.ReadByte();
if (this.Version < FormatVer)
{
throw new FormatException(string.Format("DynDnsMessage version [{0}] is not supported.", this.Version));
}
this.TimeStampUtc = new DateTime(ms.ReadInt64Le());
this.Flags = (DynDnsMessageFlag)ms.ReadInt32Le();
this.HostEntry = new DynDnsHostEntry(ms.ReadString16());
}
}
catch (Exception e)
{
throw new FormatException("Invalid Dynamic DNS message.", e);
}
}
/// <summary>
/// Registers a <see cref="DynDnsHostEntry" /> with the Dynamic DNS cluster.
/// </summary>
/// <param name="hostEntry">The host/IP address <see cref="DynDnsHostEntry" /> to be registered.</param>
/// <remarks>
/// <note>
/// This method does not throw an exception if the registration is already registered.
/// </note>
/// </remarks>
/// <exception cref="InvalidOperationException">Thrown if the client has not been started.</exception>
public void Register(DynDnsHostEntry hostEntry)
{
using (TimedLock.Lock(syncLock))
{
if (!hosts.ContainsKey(hostEntry))
{
hosts[hostEntry] = hostEntry;
Register();
}
}
}
/// <summary>
/// Returns a copy of the <see cref="DynDnsHostEntry" /> registrations currently
/// exposed to the Dynamic DNS cluster.
/// </summary>
/// <returns>A <see cref="DynDnsHostEntry" /> array listing the current registrations.</returns>
/// <exception cref="InvalidOperationException">Thrown if the client has not been started.</exception>
public DynDnsHostEntry[] GetHostRegistrations()
{
using (TimedLock.Lock(syncLock))
{
var list = new DynDnsHostEntry[hosts.Count];
int i;
i = 0;
foreach (DynDnsHostEntry hostEntry in hosts.Values)
{
list[i++] = hostEntry;
}
return(list);
}
}
/// <summary>
/// Loads DNS client settings from a configuration section.
/// </summary>
/// <param name="keyPrefix">The configuration section key prefix (or <c>null</c>).</param>
/// <remarks>
/// <para>
/// The settings will loaded are:
/// </para>
/// <div class="tablediv">
/// <table class="dtTABLE" cellspacing="0" ID="Table1">
/// <tr valign="top">
/// <th width="1">Setting</th>
/// <th width="1">Default</th>
/// <th width="90%">Description</th>
/// </tr>
/// <tr valign="top">
/// <td>Enabled</td>
/// <td>true</td>
/// <td>
/// Indicates whether the dynamic DNS client should be enabled.
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>NetworkBinding</td>
/// <td>ANY</td>
/// <td>
/// Specifies the <see cref="NetworkBinding" /> the DNS client
/// should use for sending UDP host registration messages to the
/// DNS servers.
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>Mode</td>
/// <td>Cluster</td>
/// <td>
/// Controls how the client registers hosts with the DNS server. The possible values
/// are <see cref="DynDnsMode.Udp" /> or <see cref="DynDnsMode.Cluster"/>.
/// <see cref="DynDnsMode.Both" /> is not allowed for DNS clients.
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>SharedKey</td>
/// <td>(see note)</td>
/// <td>
/// Shared symmetric encryption key used to decrypt UDP registration messages
/// sent by DNS clients while in <see cref="DynDnsMode.Udp" /> mode. This
/// key must match the shared key configured for the client. This defaults
/// to a reasonable value.
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>Domain</td>
/// <td>(see note)</td>
/// <td>
/// <para>
/// Specifies the name server domain for the name server. If this is
/// specified, the DNS client will periodically query DNS for the NS
/// records for the domain and then use the IP addresses to send UDP
/// host registration messages to the servers.
/// </para>
/// <para>
/// This setting must be formatted as a network binding with a host name
/// and port, such as <b>LILLTEK.NET:DYNAMIC-DNS</b>.
/// </para>
/// <note>
/// One of <b>Domain</b> or <b>NameServer</b> must be specified when when <b>Mode=UDP</b>.
/// If both settings are present, then <b>Domain</b> will be used.
/// </note>
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>NameServer[#]</td>
/// <td>(see note)</td>
/// <td>
/// <para>
/// Specifies the network bindings for the DNS servers for the delivery
/// of UDP host registration messages. These entries may include
/// IP addresses or host names, but note that host name lookups are
/// performed only once by the server, when it starts.
/// </para>
/// <note>
/// One of <b>Domain</b> or <b>NameServer</b> must be specified when when <b>Mode=UDP</b>.
/// If both settings are present, then <b>Domain</b> will be used.
/// </note>
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>BkInterval</td>
/// <td>1s</td>
/// <td>
/// Minimum interval for which background activities will be scheduled.
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>DomainRefreshInterval</td>
/// <td>15m</td>
/// <td>
/// Interval at which DNS NS queries will be performed to refresh the list of
/// name servers for the specified <b>Domain</b>.
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>UdpRegisterInterval</td>
/// <td>60s</td>
/// <td>
/// Interval at which UDP host registration messages will be sent to the
/// DNS servers when operating in <b>Mode=UDP</b>.
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>Host[#]</td>
/// <td>(optional)</td>
/// <td>
/// <para>
/// The set of static host entries to be returned by the DNS server. These
/// entries are formatted as:
/// </para>
/// <code lang="none">
/// <host name> "," <ip or cname> [ "," <TTL> [ "," <host-mode> [ ";" "NAT" ] ] ]
/// </code>
/// <para>
/// where <b>host name</b> is the DNS name being registered, <b>ip</b> or <b>cname</b>
/// specifies the IP address or CNAME reference to the host, <b>TTL</b> is the optional
/// time-to-live (TTL) to use for the entry in seconds, and <b>host-mode</b> is the optional
/// host entry mode, one of <b>ADDRESS</b>, <b>ADDRESSLIST</b>, or <b>CNAME</b>.
/// </para>
/// <para>
/// The <b>TTL</b> value defaults to -1 seconds (indicating that the server's default TTL
/// will be used) and the <b>host-mode</b> defaults to <b>ADDRESS</b> for IP addresses or
/// <b>CNAME</b> for CNAME references. You can also set <b>TTL=-1</b> to use the DNS server
/// default for this.
/// </para>
/// <note>
/// A host mode of <b>ADDRESS</b> or <b>ADDRESSLIST</b> can only be specified for IP
/// addresses and <b>CNAME</b> can only be specified for CNAME entries.
/// </note>
/// </td>
/// </tr>
/// <tr valign="top">
/// <td>Cluster</td>
/// <td>(see note)</td>
/// <td>
/// <b>Cluster</b> is a subsection in the configuration that
/// that specifies the settings required to establish a cooperative
/// cluster with the Dynamic DNS instances on the network while operating
/// in CLUSTER mode. The client uses the <see cref="ClusterMember" /> class
/// to perform the work necessary to join the cluster. The <b>ClusterBaseEP</b>
/// setting is required.
/// </td>
/// </tr>
/// </table>
/// </div>
/// </remarks>
public DynDnsClientSettings(string keyPrefix)
{
Config config = new Config(keyPrefix);
string[] list;
List <DynDnsHostEntry> registrations;
List <NetworkBinding> bindings;
list = config.GetArray("Host");
registrations = new List <DynDnsHostEntry>(list.Length);
for (int i = 0; i < list.Length; i++)
{
try
{
registrations.Add(DynDnsHostEntry.Parse(list[i]));
}
catch
{
SysLog.LogWarning("DynamicDnsClient: Error parsing host registration [{0}Host[{1}]={2}].", config.KeyPrefix, i, list[i]);
}
}
this.Hosts = registrations.ToArray();
list = config.GetArray("NameServer");
bindings = new List <NetworkBinding>(list.Length);
for (int i = 0; i < list.Length; i++)
{
try
{
bindings.Add(new NetworkBinding((list[i])));
}
catch
{
SysLog.LogWarning("DynamicDnsClient: Error parsing name server binding [{0}NameServer[{1}]={2}].", config.KeyPrefix, i, list[i]);
}
}
this.NameServers = bindings.ToArray();
this.Enabled = config.Get("Enabled", this.Enabled);
if (this.Enabled)
{
this.NetworkBinding = config.Get("NetworkBinding", this.NetworkBinding);
this.Mode = config.Get <DynDnsMode>("Mode", this.Mode);
this.SharedKey = new SymmetricKey(config.Get("SharedKey", "aes:BcskocQ2W4aIGEemkPsy5dhAxuWllweKLVToK1NoYzg=:5UUVxRPml8L4WH82unR74A=="));
this.Domain = config.Get("Domain", this.Domain);
this.BkInterval = config.Get("BkInterval", this.BkInterval);
this.DomainRefreshInterval = config.Get("DomainRefreshInterval", this.DomainRefreshInterval);
this.UdpRegisterInterval = config.Get("UdpRegisterInterval", this.UdpRegisterInterval);
if (this.Mode == DynDnsMode.Cluster)
{
this.Cluster = ClusterMemberSettings.LoadConfig(config.KeyPrefix + "Cluster");
}
if (this.Mode == DynDnsMode.Both)
{
throw new FormatException("DynamicDnsClient: [Mode=BOTH] is not supported.");
}
if (this.Mode == DynDnsMode.Udp && this.Domain.IsAny && this.NameServers.Length == 0)
{
throw new FormatException("DynDnsClient: One of DOMAIN or NAMESERVER[#] must be specified when [Mode=UDP].");
}
}
}
