pjsip: Handle outbound unregister correctly

This updates the status of the outbound registration
to reflect when it has been unregistered.  Since the
registration is unregistered but is not stopped, the
registration schedule remains active as before.  The
patch also updates the documentation of both the AMI
and CLI commands.

ASTERISK-24411 #close
Review: https://reviewboard.asterisk.org/r/4119/
Reported by: John Bigelow
patches:
  unregister-patch1.txt uploaded by John Bigelow (License 5091)
........

Merged revisions 426923 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@426924 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_pjsip_outbound_registration.c

@@ -138,6 +138,14 @@
 				<para>The outbound registration to unregister.</para>
 			</parameter>
 		</syntax>
+		<description>
+			<para>
+			Send a SIP REGISTER request to the specified outbound registration with an expiration of 0.
+			This will cause the contact added by this registration to be removed on the remote system.
+			Note: The specified outbound registration will attempt to re-register according to it's last
+			registration expiration.
+                        </para>
+		</description>
 	</manager>
 	<manager name="PJSIPShowRegistrationsOutbound" language="en_US">
 		<synopsis>
@@ -465,11 +473,17 @@ static int handle_registration_response(void *data)
 	}
 
 	if (PJSIP_IS_STATUS_IN_CLASS(response->code, 200)) {
-		/* If the registration went fine simply reschedule registration for the future */
-		ast_debug(1, "Outbound registration to '%s' with client '%s' successful\n", server_uri, client_uri);
-		response->client_state->status = SIP_REGISTRATION_REGISTERED;
-		response->client_state->retries = 0;
-		schedule_registration(response->client_state, response->expiration - REREGISTER_BUFFER_TIME);
+		/* Check if this is in regards to registering or unregistering */
+		if (response->expiration) {
+			/* If the registration went fine simply reschedule registration for the future */
+			ast_debug(1, "Outbound registration to '%s' with client '%s' successful\n", server_uri, client_uri);
+			response->client_state->status = SIP_REGISTRATION_REGISTERED;
+			response->client_state->retries = 0;
+			schedule_registration(response->client_state, response->expiration - REREGISTER_BUFFER_TIME);
+		} else {
+			ast_debug(1, "Outbound unregistration to '%s' with client '%s' successful\n", server_uri, client_uri);
+			response->client_state->status = SIP_REGISTRATION_UNREGISTERED;
+		}
 	} else if (response->retry_after) {
 		/* If we have been instructed to retry after a period of time, schedule it as such */
 		schedule_retry(response, response->retry_after, server_uri, client_uri);
@@ -999,7 +1013,9 @@ static char *cli_unregister(struct ast_cli_entry *e, int cmd, struct ast_cli_arg
 			"Usage: pjsip send unregister <registration>\n"
 			"       Send a SIP REGISTER request to the specified outbound "
 			"registration with an expiration of 0. This will cause the contact "
-			"added by this registration to be removed on the remote system.\n";
+			"added by this registration to be removed on the remote system. Note: "
+			"The specified outbound registration will attempt to re-register "
+			"according to its last registration expiration.\n";
 		return NULL;
 	case CLI_GENERATE:
 		return cli_complete_registration(a->line, a->word, a->pos, a->n);