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Date:      Mon, 17 May 2010 10:31:09 GMT
From:      Marko Zec <zec@FreeBSD.org>
To:        Perforce Change Reviews <perforce@freebsd.org>
Subject:   PERFORCE change 178379 for review
Message-ID:  <201005171031.o4HAV9EX099207@repoman.freebsd.org>

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http://p4web.freebsd.org/@@178379?ac=10

Change 178379 by zec@zec_nxlab on 2010/05/17 10:30:56

	Add a global counter of all V_ip_mrouter instances, which we
	consult when making a decission on wheter or not to allow the
	module to be kldunloaded.
	
	Introduce a global flag which we set when starting to kldunload
	the module, in order to prevent new V_ip_mrouter sockets to
	become attached.
	
	All of this is completely untested.

Affected files ...

.. //depot/projects/vimage/src/sys/netinet/ip_mroute.c#34 edit

Differences ...

==== //depot/projects/vimage/src/sys/netinet/ip_mroute.c#34 (text+ko) ====

@@ -142,6 +142,9 @@
 	mtx_init(&mrouter_mtx, "IPv4 multicast forwarding", NULL, MTX_DEF)
 #define	MROUTER_LOCK_DESTROY()	mtx_destroy(&mrouter_mtx)
 
+static int ip_mrouter_cnt;	/* # of vnets with active mrouters */
+static int ip_mrouter_unloading; /* Allow no more V_ip_mrouter sockets */
+
 static VNET_DEFINE(struct mrtstat, mrtstat);
 #define	V_mrtstat		VNET(mrtstat)
 SYSCTL_VNET_STRUCT(_net_inet_ip, OID_AUTO, mrtstat, CTLFLAG_RW,
@@ -673,6 +676,11 @@
 
     MROUTER_LOCK();
 
+    if (ip_mrouter_unloading) {
+	MROUTER_UNLOCK();
+	return ENOPROTOOPT;
+    }
+
     if (V_ip_mrouter != NULL) {
 	MROUTER_UNLOCK();
 	return EADDRINUSE;
@@ -694,6 +702,7 @@
     callout_reset(&bw_meter_ch, BW_METER_PERIOD, expire_bw_meter_process, curvnet);
 
     V_ip_mrouter = so;
+    ip_mrouter_cnt++;
 
     MROUTER_UNLOCK();
 
@@ -724,6 +733,7 @@
      * Detach/disable hooks to the reset of the system.
      */
     V_ip_mrouter = NULL;
+    ip_mrouter_cnt--;
     mrt_api_config = 0;
 
     VIF_LOCK();
@@ -2890,8 +2900,13 @@
 	 * just loaded and then unloaded w/o starting up a user
 	 * process we still need to cleanup.
 	 */
-	if (V_ip_mrouter != NULL)
+	MROUTER_LOCK();
+	if (ip_mrouter_cnt != 0) {
+	    MROUTER_UNLOCK();
 	    return (EINVAL);
+	}
+	ip_mrouter_unloading = 1;
+	MROUTER_UNLOCK();
 
 	if (pim_encap_cookie) {
 	    encap_detach(pim_encap_cookie);



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