From 40f667f2cdde02eb2e55b9c78fd18ded83f737bc Mon Sep 17 00:00:00 2001
From: Sepherosa Ziehau <sephe@dragonflybsd.org>
Date: Sat, 31 May 2008 06:03:26 +0000
Subject: [PATCH] Add ifa_listmask field in ifaddr_container; currently it is
 mainly used to do sanity checks.

---
 sys/net/if.c     | 28 ++++++++++++++++++----------
 sys/net/if_var.h |  5 ++++-
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/sys/net/if.c b/sys/net/if.c
index 2c84996eef..3602f653e4 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -32,7 +32,7 @@
  *
  *	@(#)if.c	8.3 (Berkeley) 1/4/94
  * $FreeBSD: src/sys/net/if.c,v 1.185 2004/03/13 02:35:03 brooks Exp $
- * $DragonFly: src/sys/net/if.c,v 1.67 2008/05/28 12:11:13 sephe Exp $
+ * $DragonFly: src/sys/net/if.c,v 1.68 2008/05/31 06:03:26 sephe Exp $
  */
 
 #include "opt_compat.h"
@@ -2211,6 +2211,8 @@ ifac_free(struct ifaddr_container *ifac, int cpu_id)
 
 	KKASSERT(ifac->ifa_magic == IFA_CONTAINER_MAGIC);
 	KKASSERT(ifac->ifa_refcnt == 0);
+	KASSERT(ifac->ifa_listmask == 0,
+		("ifa is still on %#x lists\n", ifac->ifa_listmask));
 
 	ifac->ifa_magic = IFA_CONTAINER_DEAD;
 
@@ -2244,15 +2246,17 @@ ifa_iflink_dispatch(struct netmsg *nmsg)
 	struct ifaddr *ifa = msg->ifa;
 	struct ifnet *ifp = msg->ifp;
 	int cpu = mycpuid;
+	struct ifaddr_container *ifac;
 
 	crit_enter();
-	if (msg->tail) {
-		TAILQ_INSERT_TAIL(&ifp->if_addrheads[cpu],
-				  &ifa->ifa_containers[cpu], ifa_link);
-	} else {
-		TAILQ_INSERT_HEAD(&ifp->if_addrheads[cpu],
-				  &ifa->ifa_containers[cpu], ifa_link);
-	}
+	ifac = &ifa->ifa_containers[cpu];
+	KASSERT((ifac->ifa_listmask & IFA_LIST_IFADDRHEAD) == 0,
+		("ifaddr is on if_addrheads\n"));
+	ifac->ifa_listmask |= IFA_LIST_IFADDRHEAD;
+	if (msg->tail)
+		TAILQ_INSERT_TAIL(&ifp->if_addrheads[cpu], ifac, ifa_link);
+	else
+		TAILQ_INSERT_HEAD(&ifp->if_addrheads[cpu], ifac, ifa_link);
 	crit_exit();
 
 	ifa_forwardmsg(&nmsg->nm_lmsg, cpu + 1);
@@ -2279,10 +2283,14 @@ ifa_ifunlink_dispatch(struct netmsg *nmsg)
 	struct ifaddr *ifa = msg->ifa;
 	struct ifnet *ifp = msg->ifp;
 	int cpu = mycpuid;
+	struct ifaddr_container *ifac;
 
 	crit_enter();
-	TAILQ_REMOVE(&ifp->if_addrheads[cpu],
-		     &ifa->ifa_containers[cpu], ifa_link);
+	ifac = &ifa->ifa_containers[cpu];
+	KASSERT(ifac->ifa_listmask & IFA_LIST_IFADDRHEAD,
+		("ifaddr is not on if_addrhead\n"));
+	TAILQ_REMOVE(&ifp->if_addrheads[cpu], ifac, ifa_link);
+	ifac->ifa_listmask &= ~IFA_LIST_IFADDRHEAD;
 	crit_exit();
 
 	ifa_forwardmsg(&nmsg->nm_lmsg, cpu + 1);
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index f7d87dd979..c976103599 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -32,7 +32,7 @@
  *
  *	From: @(#)if.h	8.1 (Berkeley) 6/10/93
  * $FreeBSD: src/sys/net/if_var.h,v 1.18.2.16 2003/04/15 18:11:19 fjoe Exp $
- * $DragonFly: src/sys/net/if_var.h,v 1.50 2008/05/14 11:59:23 sephe Exp $
+ * $DragonFly: src/sys/net/if_var.h,v 1.51 2008/05/31 06:03:26 sephe Exp $
  */
 
 #ifndef	_NET_IF_VAR_H_
@@ -369,8 +369,11 @@ struct ifaddr_container {
 	struct ifaddr		*ifa;
 	TAILQ_ENTRY(ifaddr_container)	ifa_link;   /* queue macro glue */
 	u_int			ifa_refcnt; /* references to this structure */
+	uint32_t		ifa_listmask;	/* IFA_LIST_ */
 };
 
+#define IFA_LIST_IFADDRHEAD	0x1	/* on ifnet.if_addrheads[cpuid] */
+
 /*
  * The ifaddr structure contains information about one address
  * of an interface.  They are maintained by the different address families,
-- 
2.41.0