Module Name:    src
Committed By:   ozaki-r
Date:           Wed Sep 25 09:52:32 UTC 2019

Modified Files:
        src/sys/netinet: if_arp.c
        src/sys/netinet6: nd6.c nd6.h nd6_nbr.c

Log Message:
Initialize DAD components properly

The original code initialized each component in non-init functions such as
arp_dad_start and nd6_dad_find, conditionally based on a global flag for each.
However, it was racy because the flag and the code around it were not
protected by a lock and could cause a kernel panic at worst.

Fix the issue by initializing the components in bootup as usual.


To generate a diff of this commit:
cvs rdiff -u -r1.287 -r1.288 src/sys/netinet/if_arp.c
cvs rdiff -u -r1.263 -r1.264 src/sys/netinet6/nd6.c
cvs rdiff -u -r1.87 -r1.88 src/sys/netinet6/nd6.h
cvs rdiff -u -r1.173 -r1.174 src/sys/netinet6/nd6_nbr.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/netinet/if_arp.c
diff -u src/sys/netinet/if_arp.c:1.287 src/sys/netinet/if_arp.c:1.288
--- src/sys/netinet/if_arp.c:1.287	Sun Sep  1 22:09:02 2019
+++ src/sys/netinet/if_arp.c	Wed Sep 25 09:52:32 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: if_arp.c,v 1.287 2019/09/01 22:09:02 roy Exp $	*/
+/*	$NetBSD: if_arp.c,v 1.288 2019/09/25 09:52:32 ozaki-r Exp $	*/
 
 /*
  * Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc.
@@ -68,7 +68,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.287 2019/09/01 22:09:02 roy Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.288 2019/09/25 09:52:32 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -153,6 +153,7 @@ int arp_debug = 0;
 #endif
 
 static void arp_init(void);
+static void arp_dad_init(void);
 
 static void arprequest(struct ifnet *,
     const struct in_addr *, const struct in_addr *,
@@ -264,6 +265,8 @@ arp_init(void)
 #ifdef MBUFTRACE
 	MOWNER_ATTACH(&arpdomain.dom_mowner);
 #endif
+
+	arp_dad_init();
 }
 
 static void
@@ -1510,10 +1513,17 @@ struct dadq {
 };
 
 static struct dadq_head dadq;
-static int dad_init = 0;
 static int dad_maxtry = 15;     /* max # of *tries* to transmit DAD packet */
 static kmutex_t arp_dad_lock;
 
+static void
+arp_dad_init(void)
+{
+
+	TAILQ_INIT(&dadq);
+	mutex_init(&arp_dad_lock, MUTEX_DEFAULT, IPL_NONE);
+}
+
 static struct dadq *
 arp_dad_find(struct ifaddr *ifa)
 {
@@ -1588,12 +1598,6 @@ arp_dad_start(struct ifaddr *ifa)
 	struct dadq *dp;
 	char ipbuf[INET_ADDRSTRLEN];
 
-	if (!dad_init) {
-		TAILQ_INIT(&dadq);
-		mutex_init(&arp_dad_lock, MUTEX_DEFAULT, IPL_NONE);
-		dad_init++;
-	}
-
 	/*
 	 * If we don't need DAD, don't do it.
 	 * - DAD is disabled
@@ -1662,9 +1666,6 @@ arp_dad_stop(struct ifaddr *ifa)
 {
 	struct dadq *dp;
 
-	if (!dad_init)
-		return;
-
 	mutex_enter(&arp_dad_lock);
 	dp = arp_dad_find(ifa);
 	if (dp == NULL) {

Index: src/sys/netinet6/nd6.c
diff -u src/sys/netinet6/nd6.c:1.263 src/sys/netinet6/nd6.c:1.264
--- src/sys/netinet6/nd6.c:1.263	Sun Sep  1 19:26:21 2019
+++ src/sys/netinet6/nd6.c	Wed Sep 25 09:52:32 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: nd6.c,v 1.263 2019/09/01 19:26:21 roy Exp $	*/
+/*	$NetBSD: nd6.c,v 1.264 2019/09/25 09:52:32 ozaki-r Exp $	*/
 /*	$KAME: nd6.c,v 1.279 2002/06/08 11:16:51 itojun Exp $	*/
 
 /*
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nd6.c,v 1.263 2019/09/01 19:26:21 roy Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd6.c,v 1.264 2019/09/25 09:52:32 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_net_mpsafe.h"
@@ -137,6 +137,8 @@ nd6_init(void)
 {
 	int error;
 
+	nd6_nbr_init();
+
 	rw_init(&nd6_lock);
 
 	/* initialization of the default router list */

Index: src/sys/netinet6/nd6.h
diff -u src/sys/netinet6/nd6.h:1.87 src/sys/netinet6/nd6.h:1.88
--- src/sys/netinet6/nd6.h:1.87	Sun Sep  1 19:26:21 2019
+++ src/sys/netinet6/nd6.h	Wed Sep 25 09:52:32 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: nd6.h,v 1.87 2019/09/01 19:26:21 roy Exp $	*/
+/*	$NetBSD: nd6.h,v 1.88 2019/09/25 09:52:32 ozaki-r Exp $	*/
 /*	$KAME: nd6.h,v 1.95 2002/06/08 11:31:06 itojun Exp $	*/
 
 /*
@@ -430,6 +430,7 @@ union nd_opts {
 /* XXX: need nd6_var.h?? */
 /* nd6.c */
 void nd6_init(void);
+void nd6_nbr_init(void);
 struct nd_ifinfo *nd6_ifattach(struct ifnet *);
 void nd6_ifdetach(struct ifnet *, struct in6_ifextra *);
 int nd6_is_addr_neighbor(const struct sockaddr_in6 *, struct ifnet *);

Index: src/sys/netinet6/nd6_nbr.c
diff -u src/sys/netinet6/nd6_nbr.c:1.173 src/sys/netinet6/nd6_nbr.c:1.174
--- src/sys/netinet6/nd6_nbr.c:1.173	Wed Sep 18 08:18:05 2019
+++ src/sys/netinet6/nd6_nbr.c	Wed Sep 25 09:52:32 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: nd6_nbr.c,v 1.173 2019/09/18 08:18:05 ozaki-r Exp $	*/
+/*	$NetBSD: nd6_nbr.c,v 1.174 2019/09/25 09:52:32 ozaki-r Exp $	*/
 /*	$KAME: nd6_nbr.c,v 1.61 2001/02/10 16:06:14 jinmei Exp $	*/
 
 /*
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.173 2019/09/18 08:18:05 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.174 2019/09/25 09:52:32 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -1124,9 +1124,16 @@ struct dadq {
 };
 
 static struct dadq_head dadq;
-static int dad_init = 0;
 static kmutex_t nd6_dad_lock;
 
+void
+nd6_nbr_init(void)
+{
+
+	TAILQ_INIT(&dadq);
+	mutex_init(&nd6_dad_lock, MUTEX_DEFAULT, IPL_NONE);
+}
+
 static struct dadq *
 nd6_dad_find(struct ifaddr *ifa, struct nd_opt_nonce *nonce, bool *found_nonce)
 {
@@ -1238,12 +1245,6 @@ nd6_dad_start(struct ifaddr *ifa, int xt
 	struct dadq *dp;
 	char ip6buf[INET6_ADDRSTRLEN];
 
-	if (!dad_init) {
-		TAILQ_INIT(&dadq);
-		mutex_init(&nd6_dad_lock, MUTEX_DEFAULT, IPL_NONE);
-		dad_init++;
-	}
-
 	/*
 	 * If we don't need DAD, don't do it.
 	 * There are several cases:
@@ -1321,9 +1322,6 @@ nd6_dad_stop(struct ifaddr *ifa)
 {
 	struct dadq *dp;
 
-	if (!dad_init)
-		return;
-
 	mutex_enter(&nd6_dad_lock);
 	dp = nd6_dad_find(ifa, NULL, NULL);
 	if (dp == NULL) {

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