GH-2874: Syslog - copy IpHeaders to message

Resolves #2874

**cherry-pick to 5.1.x**

Author: garyrussell

spring-integration-syslog/src/main/java/org/springframework/integration/syslog/DefaultMessageConverter.java

@@ -93,6 +93,7 @@ public Message<?> fromSyslog(Message<?> message) {
 			}
 		}
 		return getMessageBuilderFactory().withPayload(this.asMap ? map : message.getPayload())
+				.copyHeaders(message.getHeaders())
 				.copyHeaders(out)
 				.build();
 	}

spring-integration-syslog/src/main/java/org/springframework/integration/syslog/RFC5424MessageConverter.java

@@ -85,7 +85,8 @@ public Message<?> fromSyslog(Message<?> message) {
 		}
 
 		AbstractIntegrationMessageBuilder<Object> builder = getMessageBuilderFactory().withPayload(
-				asMap() ? map : originalContent);
+				asMap() ? map : originalContent)
+					.copyHeaders(message.getHeaders());
 		if (!asMap() && isMap) {
 			builder.copyHeaders(map);
 		}

spring-integration-syslog/src/test/java/org/springframework/integration/syslog/inbound/SyslogReceivingChannelAdapterTests.java

@@ -42,6 +42,7 @@
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.integration.channel.QueueChannel;
+import org.springframework.integration.ip.IpHeaders;
 import org.springframework.integration.ip.tcp.connection.AbstractServerConnectionFactory;
 import org.springframework.integration.ip.tcp.connection.TcpNioServerConnectionFactory;
 import org.springframework.integration.ip.udp.UnicastReceivingChannelAdapter;
@@ -84,6 +85,7 @@ public void testUdp() throws Exception {
 		Message<?> message = outputChannel.receive(10000);
 		assertThat(message).isNotNull();
 		assertThat(message.getHeaders().get("syslog_HOST")).isEqualTo("WEBERN");
+		assertThat(message.getHeaders().get(IpHeaders.IP_ADDRESS)).isNotNull();
 		adapter.stop();
 	}
 
@@ -128,6 +130,7 @@ public void testTcp() throws Exception {
 		Message<?> message = outputChannel.receive(10000);
 		assertThat(message).isNotNull();
 		assertThat(message.getHeaders().get("syslog_HOST")).isEqualTo("WEBERN");
+		assertThat(message.getHeaders().get(IpHeaders.IP_ADDRESS)).isNotNull();
 		adapter.stop();
 		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 	}
@@ -161,6 +164,7 @@ public void testAsMapFalse() throws Exception {
 		assertThat(message.getHeaders().get("syslog_HOST")).isEqualTo("WEBERN");
 		assertThat(new String((byte[]) message.getPayload(), "UTF-8"))
 				.isEqualTo("<157>JUL 26 22:08:35 WEBERN TESTING[70729]: TEST SYSLOG MESSAGE");
+		assertThat(message.getHeaders().get(IpHeaders.IP_ADDRESS)).isNotNull();
 		adapter.stop();
 	}
 
@@ -210,6 +214,7 @@ public void testTcpRFC5424() throws Exception {
 		Message<Map<String, ?>> message = (Message<Map<String, ?>>) outputChannel.receive(10000);
 		assertThat(message).isNotNull();
 		assertThat(message.getPayload().get("syslog_HOST")).isEqualTo("loggregator");
+		assertThat(message.getHeaders().get(IpHeaders.IP_ADDRESS)).isNotNull();
 		adapter.stop();
 		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 	}
@@ -243,6 +248,7 @@ public void testUdpRFC5424() throws Exception {
 		Message<Map<String, ?>> message = (Message<Map<String, ?>>) outputChannel.receive(10000);
 		assertThat(message).isNotNull();
 		assertThat(message.getPayload().get("syslog_HOST")).isEqualTo("loggregator");
+		assertThat(message.getHeaders().get(IpHeaders.IP_ADDRESS)).isNotNull();
 		adapter.stop();
 	}