src/Appender/RemoteSyslogAppender.cs - logging-log4net - Git at Google

 #region Apache License
 //
 // Licensed to the Apache Software Foundation (ASF) under one or more
 // contributor license agreements. See the NOTICE file distributed with
 // this work for additional information regarding copyright ownership.
 // The ASF licenses this file to you under the Apache License, Version 2.0
 // (the "License"); you may not use this file except in compliance with
 // the License. You may obtain a copy of the License at
 //
 // http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //
 #endregion

 using System;

 using log4net.Core;
 using log4net.Appender;
 using log4net.Util;
 using log4net.Layout;
 using System.Text;

 namespace log4net.Appender
 {
 	/// <summary>
 	/// Logs events to a remote syslog daemon.
 	/// </summary>
 	/// <remarks>
 	/// <para>
 	/// The BSD syslog protocol is used to remotely log to
 	/// a syslog daemon. The syslogd listens for for messages
 	/// on UDP port 514.
 	/// </para>
 	/// <para>
 	/// The syslog UDP protocol is not authenticated. Most syslog daemons
 	/// do not accept remote log messages because of the security implications.
 	/// You may be able to use the LocalSyslogAppender to talk to a local
 	/// syslog service.
 	/// </para>
 	/// <para>
 	/// There is an RFC 3164 that claims to document the BSD Syslog Protocol.
 	/// This RFC can be seen here: http://www.faqs.org/rfcs/rfc3164.html.
 	/// This appender generates what the RFC calls an "Original Device Message",
 	/// i.e. does not include the TIMESTAMP or HOSTNAME fields. By observation
 	/// this format of message will be accepted by all current syslog daemon
 	/// implementations. The daemon will attach the current time and the source
 	/// hostname or IP address to any messages received.
 	/// </para>
 	/// <para>
 	/// Syslog messages must have a facility and and a severity. The severity
 	/// is derived from the Level of the logging event.
 	/// The facility must be chosen from the set of defined syslog
 	/// <see cref="SyslogFacility"/> values. The facilities list is predefined
 	/// and cannot be extended.
 	/// </para>
 	/// <para>
 	/// An identifier is specified with each log message. This can be specified
 	/// by setting the <see cref="Identity"/> property. The identity (also know
 	/// as the tag) must not contain white space. The default value for the
 	/// identity is the application name (from <see cref="LoggingEvent.Domain"/>).
 	/// </para>
 	/// </remarks>
 	/// <author>Rob Lyon</author>
 	/// <author>Nicko Cadell</author>
 	public class RemoteSyslogAppender : UdpAppender
 	{
 		/// <summary>
 		/// Syslog port 514
 		/// </summary>
 		private const int DefaultSyslogPort = 514;

 		#region Enumerations

 		/// <summary>
 		/// syslog severities
 		/// </summary>
 		/// <remarks>
 		/// <para>
 		/// The syslog severities.
 		/// </para>
 		/// </remarks>
 		public enum SyslogSeverity
 		{
 			/// <summary>
 			/// system is unusable
 			/// </summary>
 			Emergency = 0,

 			/// <summary>
 			/// action must be taken immediately
 			/// </summary>
 			Alert = 1,

 			/// <summary>
 			/// critical conditions
 			/// </summary>
 			Critical = 2,

 			/// <summary>
 			/// error conditions
 			/// </summary>
 			Error = 3,

 			/// <summary>
 			/// warning conditions
 			/// </summary>
 			Warning = 4,

 			/// <summary>
 			/// normal but significant condition
 			/// </summary>
 			Notice = 5,

 			/// <summary>
 			/// informational
 			/// </summary>
 			Informational = 6,

 			/// <summary>
 			/// debug-level messages
 			/// </summary>
 			Debug = 7
 		};

 		/// <summary>
 		/// syslog facilities
 		/// </summary>
 		/// <remarks>
 		/// <para>
 		/// The syslog facilities
 		/// </para>
 		/// </remarks>
 		public enum SyslogFacility
 		{
 			/// <summary>
 			/// kernel messages
 			/// </summary>
 			Kernel = 0,

 			/// <summary>
 			/// random user-level messages
 			/// </summary>
 			User = 1,

 			/// <summary>
 			/// mail system
 			/// </summary>
 			Mail = 2,

 			/// <summary>
 			/// system daemons
 			/// </summary>
 			Daemons = 3,

 			/// <summary>
 			/// security/authorization messages
 			/// </summary>
 			Authorization = 4,

 			/// <summary>
 			/// messages generated internally by syslogd
 			/// </summary>
 			Syslog = 5,

 			/// <summary>
 			/// line printer subsystem
 			/// </summary>
 			Printer = 6,

 			/// <summary>
 			/// network news subsystem
 			/// </summary>
 			News = 7,

 			/// <summary>
 			/// UUCP subsystem
 			/// </summary>
 			Uucp = 8,

 			/// <summary>
 			/// clock (cron/at) daemon
 			/// </summary>
 			Clock = 9,

 			/// <summary>
 			/// security/authorization  messages (private)
 			/// </summary>
 			Authorization2 = 10,

 			/// <summary>
 			/// ftp daemon
 			/// </summary>
 			Ftp = 11,

 			/// <summary>
 			/// NTP subsystem
 			/// </summary>
 			Ntp = 12,

 			/// <summary>
 			/// log audit
 			/// </summary>
 			Audit = 13,

 			/// <summary>
 			/// log alert
 			/// </summary>
 			Alert = 14,

 			/// <summary>
 			/// clock daemon
 			/// </summary>
 			Clock2 = 15,

 			/// <summary>
 			/// reserved for local use
 			/// </summary>
 			Local0 = 16,

 			/// <summary>
 			/// reserved for local use
 			/// </summary>
 			Local1 = 17,

 			/// <summary>
 			/// reserved for local use
 			/// </summary>
 			Local2 = 18,

 			/// <summary>
 			/// reserved for local use
 			/// </summary>
 			Local3 = 19,

 			/// <summary>
 			/// reserved for local use
 			/// </summary>
 			Local4 = 20,

 			/// <summary>
 			/// reserved for local use
 			/// </summary>
 			Local5 = 21,

 			/// <summary>
 			/// reserved for local use
 			/// </summary>
 			Local6 = 22,

 			/// <summary>
 			/// reserved for local use
 			/// </summary>
 			Local7 = 23
 		}

 		#endregion Enumerations

 		#region Public Instance Constructors

 		/// <summary>
 		/// Initializes a new instance of the <see cref="RemoteSyslogAppender" /> class.
 		/// </summary>
 		/// <remarks>
 		/// This instance of the <see cref="RemoteSyslogAppender" /> class is set up to write
 		/// to a remote syslog daemon.
 		/// </remarks>
 		public RemoteSyslogAppender()
 		{
 			// syslog udp defaults
 			this.RemotePort = DefaultSyslogPort;
 			this.RemoteAddress = System.Net.IPAddress.Parse("127.0.0.1");
 			this.Encoding = System.Text.Encoding.ASCII;
 		}

 		#endregion Public Instance Constructors

 		#region Public Instance Properties

 		/// <summary>
 		/// Message identity
 		/// </summary>
 		/// <remarks>
 		/// <para>
 		/// An identifier is specified with each log message. This can be specified
 		/// by setting the <see cref="Identity"/> property. The identity (also know
 		/// as the tag) must not contain white space. The default value for the
 		/// identity is the application name (from <see cref="LoggingEvent.Domain"/>).
 		/// </para>
 		/// </remarks>
 		public PatternLayout Identity
 		{
 			get { return m_identity; }
 			set { m_identity = value; }
 		}

 		/// <summary>
 		/// Syslog facility
 		/// </summary>
 		/// <remarks>
 		/// Set to one of the <see cref="SyslogFacility"/> values. The list of
 		/// facilities is predefined and cannot be extended. The default value
 		/// is <see cref="SyslogFacility.User"/>.
 		/// </remarks>
 		public SyslogFacility Facility
 		{
 			get { return m_facility; }
 			set { m_facility = value; }
 		}

 		#endregion Public Instance Properties

 		/// <summary>
 		/// Add a mapping of level to severity
 		/// </summary>
 		/// <param name="mapping">The mapping to add</param>
 		/// <remarks>
 		/// <para>
 		/// Add a <see cref="LevelSeverity"/> mapping to this appender.
 		/// </para>
 		/// </remarks>
 		public void AddMapping(LevelSeverity mapping)
 		{
 			m_levelMapping.Add(mapping);
 		}

 		#region AppenderSkeleton Implementation

 		/// <summary>
 		/// This method is called by the <see cref="M:AppenderSkeleton.DoAppend(LoggingEvent)"/> method.
 		/// </summary>
 		/// <param name="loggingEvent">The event to log.</param>
 		/// <remarks>
 		/// <para>
 		/// Writes the event to a remote syslog daemon.
 		/// </para>
 		/// <para>
 		/// The format of the output will depend on the appender's layout.
 		/// </para>
 		/// </remarks>
 		protected override void Append(LoggingEvent loggingEvent)
 		{
             try
             {
                 // Priority
                 int priority = GeneratePriority(m_facility, GetSeverity(loggingEvent.Level));

                 // Identity
                 string identity;

                 if (m_identity != null)
                 {
                     identity = m_identity.Format(loggingEvent);
                 }
                 else
                 {
                     identity = loggingEvent.Domain;
                 }

                 // Message. The message goes after the tag/identity
                 string message = RenderLoggingEvent(loggingEvent);

                 Byte[] buffer;
                 int i = 0;
                 char c;

                 StringBuilder builder = new StringBuilder();

                 while (i < message.Length)
                 {
                     // Clear StringBuilder
                     builder.Length = 0;

                     // Write priority
                     builder.Append('<');
                     builder.Append(priority);
                     builder.Append('>');

                     // Write identity
                     builder.Append(identity);
                     builder.Append(": ");

                     for (; i < message.Length; i++)
                     {
                         c = message[i];

                         // Accept only visible ASCII characters and space. See RFC 3164 section 4.1.3
                         if (((int)c >= 32) && ((int)c <= 126))
                         {
                             builder.Append(c);
                         }
                         // If character is newline, break and send the current line
                         else if ((c == '\r') || (c == '\n'))
                         {
                             // Check the next character to handle \r\n or \n\r
                             if ((message.Length > i + 1) && ((message[i + 1] == '\r') || (message[i + 1] == '\n')))
                             {
                                 i++;
                             }
                             i++;
                             break;
                         }
                     }

                     // Grab as a byte array
                     buffer = this.Encoding.GetBytes(builder.ToString());

 #if NETSTANDARD1_3
                     Client.SendAsync(buffer, buffer.Length, RemoteEndPoint).Wait();
 #else
                     this.Client.Send(buffer, buffer.Length, this.RemoteEndPoint);
 #endif
                 }
             }
             catch (Exception e)
             {
                 ErrorHandler.Error(
                     "Unable to send logging event to remote syslog " +
                     this.RemoteAddress.ToString() +
                     " on port " +
                     this.RemotePort + ".",
                     e,
                     ErrorCode.WriteFailure);
             }
 		}

 		/// <summary>
 		/// Initialize the options for this appender
 		/// </summary>
 		/// <remarks>
 		/// <para>
 		/// Initialize the level to syslog severity mappings set on this appender.
 		/// </para>
 		/// </remarks>
 		public override void ActivateOptions()
 		{
 			base.ActivateOptions();
 			m_levelMapping.ActivateOptions();
 		}

 		#endregion AppenderSkeleton Implementation

 		#region Protected Members

 		/// <summary>
 		/// Translates a log4net level to a syslog severity.
 		/// </summary>
 		/// <param name="level">A log4net level.</param>
 		/// <returns>A syslog severity.</returns>
 		/// <remarks>
 		/// <para>
 		/// Translates a log4net level to a syslog severity.
 		/// </para>
 		/// </remarks>
 		virtual protected SyslogSeverity GetSeverity(Level level)
 		{
 			LevelSeverity levelSeverity = m_levelMapping.Lookup(level) as LevelSeverity;
 			if (levelSeverity != null)
 			{
 				return levelSeverity.Severity;
 			}

 			//
 			// Fallback to sensible default values
 			//

 			if (level >= Level.Alert)
 			{
 				return SyslogSeverity.Alert;
 			}
 			else if (level >= Level.Critical)
 			{
 				return SyslogSeverity.Critical;
 			}
 			else if (level >= Level.Error)
 			{
 				return SyslogSeverity.Error;
 			}
 			else if (level >= Level.Warn)
 			{
 				return SyslogSeverity.Warning;
 			}
 			else if (level >= Level.Notice)
 			{
 				return SyslogSeverity.Notice;
 			}
 			else if (level >= Level.Info)
 			{
 				return SyslogSeverity.Informational;
 			}
 			// Default setting
 			return SyslogSeverity.Debug;
 		}

 		#endregion Protected Members

 		#region Public Static Members

 		/// <summary>
 		/// Generate a syslog priority.
 		/// </summary>
 		/// <param name="facility">The syslog facility.</param>
 		/// <param name="severity">The syslog severity.</param>
 		/// <returns>A syslog priority.</returns>
 		/// <remarks>
 		/// <para>
 		/// Generate a syslog priority.
 		/// </para>
 		/// </remarks>
 		public static int GeneratePriority(SyslogFacility facility, SyslogSeverity severity)
 		{
 			if (facility < SyslogFacility.Kernel || facility > SyslogFacility.Local7)
 			{
 				throw new ArgumentException("SyslogFacility out of range", "facility");
 			}

 			if (severity < SyslogSeverity.Emergency || severity > SyslogSeverity.Debug)
 			{
 				throw new ArgumentException("SyslogSeverity out of range", "severity");
 			}

 			unchecked
 			{
 				return ((int)facility * 8) + (int)severity;
 			}
 		}

 		#endregion Public Static Members

 		#region Private Instances Fields

 		/// <summary>
 		/// The facility. The default facility is <see cref="SyslogFacility.User"/>.
 		/// </summary>
 		private SyslogFacility m_facility = SyslogFacility.User;

 		/// <summary>
 		/// The message identity
 		/// </summary>
 		private PatternLayout m_identity;

 		/// <summary>
 		/// Mapping from level object to syslog severity
 		/// </summary>
 		private LevelMapping m_levelMapping = new LevelMapping();

 		/// <summary>
 		/// Initial buffer size
 		/// </summary>
 		private const int c_renderBufferSize = 256;

 		/// <summary>
 		/// Maximum buffer size before it is recycled
 		/// </summary>
 		private const int c_renderBufferMaxCapacity = 1024;

 		#endregion Private Instances Fields

 		#region LevelSeverity LevelMapping Entry
 		/// <summary>
 		/// A class to act as a mapping between the level that a logging call is made at and
 		/// the syslog severity that is should be logged at.
 		/// </summary>
 		/// <remarks>
 		/// <para>
 		/// A class to act as a mapping between the level that a logging call is made at and
 		/// the syslog severity that is should be logged at.
 		/// </para>
 		/// </remarks>
 		public class LevelSeverity : LevelMappingEntry
 		{
 			private SyslogSeverity m_severity;

 			/// <summary>
 			/// The mapped syslog severity for the specified level
 			/// </summary>
 			/// <remarks>
 			/// <para>
 			/// Required property.
 			/// The mapped syslog severity for the specified level
 			/// </para>
 			/// </remarks>
 			public SyslogSeverity Severity
 			{
 				get { return m_severity; }
 				set { m_severity = value; }
 			}
 		}

 		#endregion // LevelSeverity LevelMapping Entry
 	}
 }
	#region Apache License
	//
	// Licensed to the Apache Software Foundation (ASF) under one or more
	// contributor license agreements. See the NOTICE file distributed with
	// this work for additional information regarding copyright ownership.
	// The ASF licenses this file to you under the Apache License, Version 2.0
	// (the "License"); you may not use this file except in compliance with
	// the License. You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.
	//
	#endregion

	using System;

	using log4net.Core;
	using log4net.Appender;
	using log4net.Util;
	using log4net.Layout;
	using System.Text;

	namespace log4net.Appender
	{
	/// <summary>
	/// Logs events to a remote syslog daemon.
	/// </summary>
	/// <remarks>
	/// <para>
	/// The BSD syslog protocol is used to remotely log to
	/// a syslog daemon. The syslogd listens for for messages
	/// on UDP port 514.
	/// </para>
	/// <para>
	/// The syslog UDP protocol is not authenticated. Most syslog daemons
	/// do not accept remote log messages because of the security implications.
	/// You may be able to use the LocalSyslogAppender to talk to a local
	/// syslog service.
	/// </para>
	/// <para>
	/// There is an RFC 3164 that claims to document the BSD Syslog Protocol.
	/// This RFC can be seen here: http://www.faqs.org/rfcs/rfc3164.html.
	/// This appender generates what the RFC calls an "Original Device Message",
	/// i.e. does not include the TIMESTAMP or HOSTNAME fields. By observation
	/// this format of message will be accepted by all current syslog daemon
	/// implementations. The daemon will attach the current time and the source
	/// hostname or IP address to any messages received.
	/// </para>
	/// <para>
	/// Syslog messages must have a facility and and a severity. The severity
	/// is derived from the Level of the logging event.
	/// The facility must be chosen from the set of defined syslog
	/// <see cref="SyslogFacility"/> values. The facilities list is predefined
	/// and cannot be extended.
	/// </para>
	/// <para>
	/// An identifier is specified with each log message. This can be specified
	/// by setting the <see cref="Identity"/> property. The identity (also know
	/// as the tag) must not contain white space. The default value for the
	/// identity is the application name (from <see cref="LoggingEvent.Domain"/>).
	/// </para>
	/// </remarks>
	/// <author>Rob Lyon</author>
	/// <author>Nicko Cadell</author>
	public class RemoteSyslogAppender : UdpAppender
	{
	/// <summary>
	/// Syslog port 514
	/// </summary>
	private const int DefaultSyslogPort = 514;

	#region Enumerations

	/// <summary>
	/// syslog severities
	/// </summary>
	/// <remarks>
	/// <para>
	/// The syslog severities.
	/// </para>
	/// </remarks>
	public enum SyslogSeverity
	{
	/// <summary>
	/// system is unusable
	/// </summary>
	Emergency = 0,

	/// <summary>
	/// action must be taken immediately
	/// </summary>
	Alert = 1,

	/// <summary>
	/// critical conditions
	/// </summary>
	Critical = 2,

	/// <summary>
	/// error conditions
	/// </summary>
	Error = 3,

	/// <summary>
	/// warning conditions
	/// </summary>
	Warning = 4,

	/// <summary>
	/// normal but significant condition
	/// </summary>
	Notice = 5,

	/// <summary>
	/// informational
	/// </summary>
	Informational = 6,

	/// <summary>
	/// debug-level messages
	/// </summary>
	Debug = 7
	};

	/// <summary>
	/// syslog facilities
	/// </summary>
	/// <remarks>
	/// <para>
	/// The syslog facilities
	/// </para>
	/// </remarks>
	public enum SyslogFacility
	{
	/// <summary>
	/// kernel messages
	/// </summary>
	Kernel = 0,

	/// <summary>
	/// random user-level messages
	/// </summary>
	User = 1,

	/// <summary>
	/// mail system
	/// </summary>
	Mail = 2,

	/// <summary>
	/// system daemons
	/// </summary>
	Daemons = 3,

	/// <summary>
	/// security/authorization messages
	/// </summary>
	Authorization = 4,

	/// <summary>
	/// messages generated internally by syslogd
	/// </summary>
	Syslog = 5,

	/// <summary>
	/// line printer subsystem
	/// </summary>
	Printer = 6,

	/// <summary>
	/// network news subsystem
	/// </summary>
	News = 7,

	/// <summary>
	/// UUCP subsystem
	/// </summary>
	Uucp = 8,

	/// <summary>
	/// clock (cron/at) daemon
	/// </summary>
	Clock = 9,

	/// <summary>
	/// security/authorization messages (private)
	/// </summary>
	Authorization2 = 10,

	/// <summary>
	/// ftp daemon
	/// </summary>
	Ftp = 11,

	/// <summary>
	/// NTP subsystem
	/// </summary>
	Ntp = 12,

	/// <summary>
	/// log audit
	/// </summary>
	Audit = 13,

	/// <summary>
	/// log alert
	/// </summary>
	Alert = 14,

	/// <summary>
	/// clock daemon
	/// </summary>
	Clock2 = 15,

	/// <summary>
	/// reserved for local use
	/// </summary>
	Local0 = 16,

	/// <summary>
	/// reserved for local use
	/// </summary>
	Local1 = 17,

	/// <summary>
	/// reserved for local use
	/// </summary>
	Local2 = 18,

	/// <summary>
	/// reserved for local use
	/// </summary>
	Local3 = 19,

	/// <summary>
	/// reserved for local use
	/// </summary>
	Local4 = 20,

	/// <summary>
	/// reserved for local use
	/// </summary>
	Local5 = 21,

	/// <summary>
	/// reserved for local use
	/// </summary>
	Local6 = 22,

	/// <summary>
	/// reserved for local use
	/// </summary>
	Local7 = 23
	}

	#endregion Enumerations

	#region Public Instance Constructors

	/// <summary>
	/// Initializes a new instance of the <see cref="RemoteSyslogAppender" /> class.
	/// </summary>
	/// <remarks>
	/// This instance of the <see cref="RemoteSyslogAppender" /> class is set up to write
	/// to a remote syslog daemon.
	/// </remarks>
	public RemoteSyslogAppender()
	{
	// syslog udp defaults
	this.RemotePort = DefaultSyslogPort;
	this.RemoteAddress = System.Net.IPAddress.Parse("127.0.0.1");
	this.Encoding = System.Text.Encoding.ASCII;
	}

	#endregion Public Instance Constructors

	#region Public Instance Properties

	/// <summary>
	/// Message identity
	/// </summary>
	/// <remarks>
	/// <para>
	/// An identifier is specified with each log message. This can be specified
	/// by setting the <see cref="Identity"/> property. The identity (also know
	/// as the tag) must not contain white space. The default value for the
	/// identity is the application name (from <see cref="LoggingEvent.Domain"/>).
	/// </para>
	/// </remarks>
	public PatternLayout Identity
	{
	get { return m_identity; }
	set { m_identity = value; }
	}

	/// <summary>
	/// Syslog facility
	/// </summary>
	/// <remarks>
	/// Set to one of the <see cref="SyslogFacility"/> values. The list of
	/// facilities is predefined and cannot be extended. The default value
	/// is <see cref="SyslogFacility.User"/>.
	/// </remarks>
	public SyslogFacility Facility
	{
	get { return m_facility; }
	set { m_facility = value; }
	}

	#endregion Public Instance Properties

	/// <summary>
	/// Add a mapping of level to severity
	/// </summary>
	/// <param name="mapping">The mapping to add</param>
	/// <remarks>
	/// <para>
	/// Add a <see cref="LevelSeverity"/> mapping to this appender.
	/// </para>
	/// </remarks>
	public void AddMapping(LevelSeverity mapping)
	{
	m_levelMapping.Add(mapping);
	}

	#region AppenderSkeleton Implementation

	/// <summary>
	/// This method is called by the <see cref="M:AppenderSkeleton.DoAppend(LoggingEvent)"/> method.
	/// </summary>
	/// <param name="loggingEvent">The event to log.</param>
	/// <remarks>
	/// <para>
	/// Writes the event to a remote syslog daemon.
	/// </para>
	/// <para>
	/// The format of the output will depend on the appender's layout.
	/// </para>
	/// </remarks>
	protected override void Append(LoggingEvent loggingEvent)
	{
	try
	{
	// Priority
	int priority = GeneratePriority(m_facility, GetSeverity(loggingEvent.Level));

	// Identity
	string identity;

	if (m_identity != null)
	{
	identity = m_identity.Format(loggingEvent);
	}
	else
	{
	identity = loggingEvent.Domain;
	}

	// Message. The message goes after the tag/identity
	string message = RenderLoggingEvent(loggingEvent);

	Byte[] buffer;
	int i = 0;
	char c;

	StringBuilder builder = new StringBuilder();

	while (i < message.Length)
	{
	// Clear StringBuilder
	builder.Length = 0;

	// Write priority
	builder.Append('<');
	builder.Append(priority);
	builder.Append('>');

	// Write identity
	builder.Append(identity);
	builder.Append(": ");

	for (; i < message.Length; i++)
	{
	c = message[i];

	// Accept only visible ASCII characters and space. See RFC 3164 section 4.1.3
	if (((int)c >= 32) && ((int)c <= 126))
	{
	builder.Append(c);
	}
	// If character is newline, break and send the current line
	else if ((c == '\r') \|\| (c == '\n'))
	{
	// Check the next character to handle \r\n or \n\r
	if ((message.Length > i + 1) && ((message[i + 1] == '\r') \|\| (message[i + 1] == '\n')))
	{
	i++;
	}
	i++;
	break;
	}
	}

	// Grab as a byte array
	buffer = this.Encoding.GetBytes(builder.ToString());

	#if NETSTANDARD1_3
	Client.SendAsync(buffer, buffer.Length, RemoteEndPoint).Wait();
	#else
	this.Client.Send(buffer, buffer.Length, this.RemoteEndPoint);
	#endif
	}
	}
	catch (Exception e)
	{
	ErrorHandler.Error(
	"Unable to send logging event to remote syslog " +
	this.RemoteAddress.ToString() +
	" on port " +
	this.RemotePort + ".",
	e,
	ErrorCode.WriteFailure);
	}
	}

	/// <summary>
	/// Initialize the options for this appender
	/// </summary>
	/// <remarks>
	/// <para>
	/// Initialize the level to syslog severity mappings set on this appender.
	/// </para>
	/// </remarks>
	public override void ActivateOptions()
	{
	base.ActivateOptions();
	m_levelMapping.ActivateOptions();
	}

	#endregion AppenderSkeleton Implementation

	#region Protected Members

	/// <summary>
	/// Translates a log4net level to a syslog severity.
	/// </summary>
	/// <param name="level">A log4net level.</param>
	/// <returns>A syslog severity.</returns>
	/// <remarks>
	/// <para>
	/// Translates a log4net level to a syslog severity.
	/// </para>
	/// </remarks>
	virtual protected SyslogSeverity GetSeverity(Level level)
	{
	LevelSeverity levelSeverity = m_levelMapping.Lookup(level) as LevelSeverity;
	if (levelSeverity != null)
	{
	return levelSeverity.Severity;
	}

	//
	// Fallback to sensible default values
	//

	if (level >= Level.Alert)
	{
	return SyslogSeverity.Alert;
	}
	else if (level >= Level.Critical)
	{
	return SyslogSeverity.Critical;
	}
	else if (level >= Level.Error)
	{
	return SyslogSeverity.Error;
	}
	else if (level >= Level.Warn)
	{
	return SyslogSeverity.Warning;
	}
	else if (level >= Level.Notice)
	{
	return SyslogSeverity.Notice;
	}
	else if (level >= Level.Info)
	{
	return SyslogSeverity.Informational;
	}
	// Default setting
	return SyslogSeverity.Debug;
	}

	#endregion Protected Members

	#region Public Static Members

	/// <summary>
	/// Generate a syslog priority.
	/// </summary>
	/// <param name="facility">The syslog facility.</param>
	/// <param name="severity">The syslog severity.</param>
	/// <returns>A syslog priority.</returns>
	/// <remarks>
	/// <para>
	/// Generate a syslog priority.
	/// </para>
	/// </remarks>
	public static int GeneratePriority(SyslogFacility facility, SyslogSeverity severity)
	{
	if (facility < SyslogFacility.Kernel \|\| facility > SyslogFacility.Local7)
	{
	throw new ArgumentException("SyslogFacility out of range", "facility");
	}

	if (severity < SyslogSeverity.Emergency \|\| severity > SyslogSeverity.Debug)
	{
	throw new ArgumentException("SyslogSeverity out of range", "severity");
	}

	unchecked
	{
	return ((int)facility * 8) + (int)severity;
	}
	}

	#endregion Public Static Members

	#region Private Instances Fields

	/// <summary>
	/// The facility. The default facility is <see cref="SyslogFacility.User"/>.
	/// </summary>
	private SyslogFacility m_facility = SyslogFacility.User;

	/// <summary>
	/// The message identity
	/// </summary>
	private PatternLayout m_identity;

	/// <summary>
	/// Mapping from level object to syslog severity
	/// </summary>
	private LevelMapping m_levelMapping = new LevelMapping();

	/// <summary>
	/// Initial buffer size
	/// </summary>
	private const int c_renderBufferSize = 256;

	/// <summary>
	/// Maximum buffer size before it is recycled
	/// </summary>
	private const int c_renderBufferMaxCapacity = 1024;

	#endregion Private Instances Fields

	#region LevelSeverity LevelMapping Entry
	/// <summary>
	/// A class to act as a mapping between the level that a logging call is made at and
	/// the syslog severity that is should be logged at.
	/// </summary>
	/// <remarks>
	/// <para>
	/// A class to act as a mapping between the level that a logging call is made at and
	/// the syslog severity that is should be logged at.
	/// </para>
	/// </remarks>
	public class LevelSeverity : LevelMappingEntry
	{
	private SyslogSeverity m_severity;

	/// <summary>
	/// The mapped syslog severity for the specified level
	/// </summary>
	/// <remarks>
	/// <para>
	/// Required property.
	/// The mapped syslog severity for the specified level
	/// </para>
	/// </remarks>
	public SyslogSeverity Severity
	{
	get { return m_severity; }
	set { m_severity = value; }
	}
	}

	#endregion // LevelSeverity LevelMapping Entry
	}
	}