From: Frank Kardel <kardel@ntp.org>
Date: Sun, 30 Sep 2007 16:05:00 +0000 (+0000)
Subject: ntp_io.c:
X-Git-Tag: NTP_4_2_5P81~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=45dfa453c516234a7e7db3f848e5ba8ba3a4c2c9;p=thirdparty%2Fntp.git

ntp_io.c:
  Bug 912: detect conflicting enable/disable configuration on interfaces sharing an IP address
ChangeLog:
  [Bug 912] detect conflicting enable/disable configuration on interfaces sharing an IP address

bk: 46ffc92cInDxBxi75cWEuhUgRDcVoQ
---

diff --git a/ChangeLog b/ChangeLog
index cc40f91e8..dc0d12526 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,4 @@
+* [Bug 912] detect conflicting enable/disable configuration on interfaces sharing an IP address
 * [Bug 771] compare scopeid if available for IPv6 addresses
 * [Bug 899] Only show -i/--jaildir -u/--user options if we HAVE_DROPROOT.
 * [Bug 916] 'cryptosw' is undefined if built without OpenSSL.
diff --git a/ntpd/ntp_io.c b/ntpd/ntp_io.c
index 8544a1ec1..545b42182 100644
--- a/ntpd/ntp_io.c
+++ b/ntpd/ntp_io.c
@@ -603,7 +603,7 @@ print_interface(struct interface *iface, char *pfx, char *sfx)
 	       iface->flags,
 	       iface->scopeid,
 	       iface->ifindex);
-	/* Leave these as three printf calls. */
+	/* Leave these as three printf calls (stoa() static buffer). */
 	printf(", sin=%s",
 	       stoa((&iface->sin)));
 	if (iface->flags & INT_BROADCAST)
@@ -1275,9 +1275,46 @@ update_interfaces(
 			/*
 			 * found existing and up to date interface - mark present
 			 */
+			if (iface->phase != sys_interphase)
+			{
+				/*
+				 * on a new round we reset the name so the interface name
+				 * shows up again if this address is not shared any more
+				 * same reasoning goes for the enable flag
+				 */
+				strcpy(iface->name, interface.name);
+				iface->ignore_packets = interface.ignore_packets;
+			} else {
+				/*
+				 * name collision - rename interface name to "*multiple*"
+				 */
+				strcpy(iface->name, "*multiple*");
+			}
 
-			iface->phase = sys_interphase;
 			DPRINT_INTERFACE(4, (iface, "updating ", " present\n"));
+
+			if (iface->ignore_packets != interface.ignore_packets)
+			{
+				/*
+				 * We have conflicting configurations for the interface address.
+				 * This is caused by using -I <interfacename> for an interface
+				 * that shares it address with other interfaces. We cannot disambiguate
+				 * incoming pakets being delivered to this socket without extra
+				 * syscalls/features. These are not (commonly) available.
+				 * Note is is a more unusual configuration where several interfaces
+				 * share an address but filtering via interface name is attempted.
+				 * We resolve the configuration conflict by disabling the reception
+				 * of pakets. This leads to a basically non-functional service on the
+				 * interface address where the conflict occurs.
+				 */
+				msyslog(LOG_ERR, "WARNING: conflicting enable configuration for interfaces %s and %s for address %s - unsupported configuration - address DISABLED",
+					interface.name, iface->name, stoa(&interface.sin));
+
+				iface->ignore_packets = ISC_TRUE;				
+			}
+
+			iface->phase = sys_interphase;
+
 			ifi.action = IFS_EXISTS;
 			ifi.interface = iface;
 			if (receiver)