Module Name: src
Committed By: ozaki-r
Date: Mon Jul 25 04:21:20 UTC 2016
Modified Files:
src/sys/netinet: if_arp.c
src/sys/netinet6: nd6_nbr.c
Log Message:
Make DAD of ARP/NDP MP-safe with coarse-grained locks
The change also prevents arp_dad_timer/nd6_dad_timer from running if
arp_dad_stop/nd6_dad_stop is called, which makes sure that callout_reset
won't be called during callout_halt.
To generate a diff of this commit:
cvs rdiff -u -r1.218 -r1.219 src/sys/netinet/if_arp.c
cvs rdiff -u -r1.124 -r1.125 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:1.218 src/sys/netinet/if_arp.c:1.219
--- src/sys/netinet/if_arp.c:1.218 Mon Jul 25 01:52:21 2016
+++ src/sys/netinet/if_arp.c Mon Jul 25 04:21:19 2016
@@ -1,4 +1,4 @@
-/* $NetBSD: if_arp.c,v 1.218 2016/07/25 01:52:21 ozaki-r Exp $ */
+/* $NetBSD: if_arp.c,v 1.219 2016/07/25 04:21:19 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 1.218 2016/07/25 01:52:21 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.219 2016/07/25 04:21:19 ozaki-r Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddb.h"
@@ -1477,12 +1477,15 @@ MALLOC_JUSTDEFINE(M_IPARP, "ARP DAD", "A
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 struct dadq *
arp_dad_find(struct ifaddr *ifa)
{
struct dadq *dp;
+ KASSERT(mutex_owned(&arp_dad_lock));
+
TAILQ_FOREACH(dp, &dadq, dad_list) {
if (dp->dad_ifa == ifa)
return dp;
@@ -1537,6 +1540,7 @@ arp_dad_start(struct ifaddr *ifa)
if (!dad_init) {
TAILQ_INIT(&dadq);
+ mutex_init(&arp_dad_lock, MUTEX_DEFAULT, IPL_NONE);
dad_init++;
}
@@ -1563,13 +1567,17 @@ arp_dad_start(struct ifaddr *ifa)
KASSERT(ifa->ifa_ifp != NULL);
if (!(ifa->ifa_ifp->if_flags & IFF_UP))
return;
+
+ mutex_enter(&arp_dad_lock);
if (arp_dad_find(ifa) != NULL) {
+ mutex_exit(&arp_dad_lock);
/* DAD already in progress */
return;
}
dp = malloc(sizeof(*dp), M_IPARP, M_NOWAIT);
if (dp == NULL) {
+ mutex_exit(&arp_dad_lock);
log(LOG_ERR, "%s: memory allocation failed for %s(%s)\n",
__func__, in_fmtaddr(ia->ia_addr.sin_addr),
ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
@@ -1577,10 +1585,6 @@ arp_dad_start(struct ifaddr *ifa)
}
memset(dp, 0, sizeof(*dp));
callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE);
- TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
-
- arplog((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
- in_fmtaddr(ia->ia_addr.sin_addr)));
/*
* Send ARP packet for DAD, ip_dad_count times.
@@ -1591,8 +1595,14 @@ arp_dad_start(struct ifaddr *ifa)
dp->dad_count = ip_dad_count;
dp->dad_arp_announce = 0; /* Will be set when starting to announce */
dp->dad_arp_acount = dp->dad_arp_ocount = dp->dad_arp_tcount = 0;
+ TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
+
+ arplog((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
+ in_fmtaddr(ia->ia_addr.sin_addr)));
arp_dad_starttimer(dp, cprng_fast32() % (PROBE_WAIT * hz));
+
+ mutex_exit(&arp_dad_lock);
}
/*
@@ -1605,15 +1615,21 @@ arp_dad_stop(struct ifaddr *ifa)
if (!dad_init)
return;
+
+ mutex_enter(&arp_dad_lock);
dp = arp_dad_find(ifa);
if (dp == NULL) {
+ mutex_exit(&arp_dad_lock);
/* DAD wasn't started yet */
return;
}
+ /* Prevent the timer from running anymore. */
+ TAILQ_REMOVE(&dadq, dp, dad_list);
+ mutex_exit(&arp_dad_lock);
+
arp_dad_stoptimer(dp);
- TAILQ_REMOVE(&dadq, dp, dad_list);
free(dp, M_IPARP);
dp = NULL;
ifafree(ifa);
@@ -1628,6 +1644,7 @@ arp_dad_timer(struct ifaddr *ifa)
mutex_enter(softnet_lock);
KERNEL_LOCK(1, NULL);
+ mutex_enter(&arp_dad_lock);
/* Sanity check */
if (ia == NULL) {
@@ -1636,7 +1653,7 @@ arp_dad_timer(struct ifaddr *ifa)
}
dp = arp_dad_find(ifa);
if (dp == NULL) {
- log(LOG_ERR, "%s: DAD structure not found\n", __func__);
+ /* DAD seems to be stopping, so do nothing. */
goto done;
}
if (ia->ia4_flags & IN_IFF_DUPLICATED) {
@@ -1719,6 +1736,7 @@ announce:
ifafree(ifa);
done:
+ mutex_exit(&arp_dad_lock);
KERNEL_UNLOCK_ONE(NULL);
mutex_exit(softnet_lock);
}
@@ -1730,9 +1748,11 @@ arp_dad_duplicated(struct ifaddr *ifa)
struct ifnet *ifp;
struct dadq *dp;
+ mutex_enter(&arp_dad_lock);
dp = arp_dad_find(ifa);
if (dp == NULL) {
- log(LOG_ERR, "%s: DAD structure not found\n", __func__);
+ mutex_exit(&arp_dad_lock);
+ /* DAD seems to be stopping, so do nothing. */
return;
}
@@ -1752,6 +1772,8 @@ arp_dad_duplicated(struct ifaddr *ifa)
rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL);
TAILQ_REMOVE(&dadq, dp, dad_list);
+ mutex_exit(&arp_dad_lock);
+
free(dp, M_IPARP);
dp = NULL;
ifafree(ifa);
Index: src/sys/netinet6/nd6_nbr.c
diff -u src/sys/netinet6/nd6_nbr.c:1.124 src/sys/netinet6/nd6_nbr.c:1.125
--- src/sys/netinet6/nd6_nbr.c:1.124 Mon Jul 25 01:52:21 2016
+++ src/sys/netinet6/nd6_nbr.c Mon Jul 25 04:21:20 2016
@@ -1,4 +1,4 @@
-/* $NetBSD: nd6_nbr.c,v 1.124 2016/07/25 01:52:21 ozaki-r Exp $ */
+/* $NetBSD: nd6_nbr.c,v 1.125 2016/07/25 04:21:20 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 1.124 2016/07/25 01:52:21 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.125 2016/07/25 04:21:20 ozaki-r Exp $");
#ifdef _KERNEL_OPT
#include "opt_inet.h"
@@ -1049,12 +1049,15 @@ struct dadq {
static struct dadq_head dadq;
static int dad_init = 0;
+static kmutex_t nd6_dad_lock;
static struct dadq *
nd6_dad_find(struct ifaddr *ifa)
{
struct dadq *dp;
+ KASSERT(mutex_owned(&nd6_dad_lock));
+
TAILQ_FOREACH(dp, &dadq, dad_list) {
if (dp->dad_ifa == ifa)
return dp;
@@ -1092,6 +1095,7 @@ nd6_dad_start(struct ifaddr *ifa, int xt
if (!dad_init) {
TAILQ_INIT(&dadq);
+ mutex_init(&nd6_dad_lock, MUTEX_DEFAULT, IPL_NONE);
dad_init++;
}
@@ -1117,13 +1121,17 @@ nd6_dad_start(struct ifaddr *ifa, int xt
KASSERT(ifa->ifa_ifp != NULL);
if (!(ifa->ifa_ifp->if_flags & IFF_UP))
return;
+
+ mutex_enter(&nd6_dad_lock);
if (nd6_dad_find(ifa) != NULL) {
+ mutex_exit(&nd6_dad_lock);
/* DAD already in progress */
return;
}
dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
if (dp == NULL) {
+ mutex_exit(&nd6_dad_lock);
log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
"%s(%s)\n",
ip6_sprintf(&ia->ia_addr.sin6_addr),
@@ -1132,10 +1140,6 @@ nd6_dad_start(struct ifaddr *ifa, int xt
}
memset(dp, 0, sizeof(*dp));
callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE);
- TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
-
- nd6log(LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
- ip6_sprintf(&ia->ia_addr.sin6_addr));
/*
* Send NS packet for DAD, ip6_dad_count times.
@@ -1148,12 +1152,18 @@ nd6_dad_start(struct ifaddr *ifa, int xt
dp->dad_count = ip6_dad_count;
dp->dad_ns_icount = dp->dad_na_icount = 0;
dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
+ TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
+
+ nd6log(LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
+ ip6_sprintf(&ia->ia_addr.sin6_addr));
+
if (xtick == 0) {
nd6_dad_ns_output(dp, ifa);
nd6_dad_starttimer(dp,
(long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
} else
nd6_dad_starttimer(dp, xtick);
+ mutex_exit(&nd6_dad_lock);
}
/*
@@ -1166,15 +1176,21 @@ nd6_dad_stop(struct ifaddr *ifa)
if (!dad_init)
return;
+
+ mutex_enter(&nd6_dad_lock);
dp = nd6_dad_find(ifa);
if (dp == NULL) {
+ mutex_exit(&nd6_dad_lock);
/* DAD wasn't started yet */
return;
}
+ /* Prevent the timer from running anymore. */
+ TAILQ_REMOVE(&dadq, dp, dad_list);
+ mutex_exit(&nd6_dad_lock);
+
nd6_dad_stoptimer(dp);
- TAILQ_REMOVE(&dadq, dp, dad_list);
free(dp, M_IP6NDP);
dp = NULL;
ifafree(ifa);
@@ -1188,6 +1204,7 @@ nd6_dad_timer(struct ifaddr *ifa)
mutex_enter(softnet_lock);
KERNEL_LOCK(1, NULL);
+ mutex_enter(&nd6_dad_lock);
/* Sanity check */
if (ia == NULL) {
@@ -1196,7 +1213,7 @@ nd6_dad_timer(struct ifaddr *ifa)
}
dp = nd6_dad_find(ifa);
if (dp == NULL) {
- log(LOG_ERR, "nd6_dad_timer: DAD structure not found\n");
+ /* DAD seems to be stopping, so do nothing. */
goto done;
}
if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
@@ -1281,6 +1298,7 @@ nd6_dad_timer(struct ifaddr *ifa)
}
done:
+ mutex_exit(&nd6_dad_lock);
KERNEL_UNLOCK_ONE(NULL);
mutex_exit(softnet_lock);
}
@@ -1292,9 +1310,11 @@ nd6_dad_duplicated(struct ifaddr *ifa)
struct ifnet *ifp;
struct dadq *dp;
+ mutex_enter(&nd6_dad_lock);
dp = nd6_dad_find(ifa);
if (dp == NULL) {
- log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
+ mutex_exit(&nd6_dad_lock);
+ /* DAD seems to be stopping, so do nothing. */
return;
}
@@ -1353,6 +1373,8 @@ nd6_dad_duplicated(struct ifaddr *ifa)
}
TAILQ_REMOVE(&dadq, dp, dad_list);
+ mutex_exit(&nd6_dad_lock);
+
free(dp, M_IP6NDP);
dp = NULL;
ifafree(ifa);
@@ -1397,6 +1419,8 @@ nd6_dad_ns_input(struct ifaddr *ifa)
ia = (struct in6_ifaddr *)ifa;
taddr6 = &ia->ia_addr.sin6_addr;
duplicate = 0;
+
+ mutex_enter(&nd6_dad_lock);
dp = nd6_dad_find(ifa);
/* Quickhack - completely ignore DAD NS packets */
@@ -1418,6 +1442,7 @@ nd6_dad_ns_input(struct ifaddr *ifa)
if (duplicate) {
dp = NULL; /* will be freed in nd6_dad_duplicated() */
+ mutex_exit(&nd6_dad_lock);
nd6_dad_duplicated(ifa);
} else {
/*
@@ -1426,6 +1451,7 @@ nd6_dad_ns_input(struct ifaddr *ifa)
*/
if (dp)
dp->dad_ns_icount++;
+ mutex_exit(&nd6_dad_lock);
}
}
@@ -1437,9 +1463,11 @@ nd6_dad_na_input(struct ifaddr *ifa)
if (ifa == NULL)
panic("ifa == NULL in nd6_dad_na_input");
+ mutex_enter(&nd6_dad_lock);
dp = nd6_dad_find(ifa);
if (dp)
dp->dad_na_icount++;
+ mutex_exit(&nd6_dad_lock);
/* remove the address. */
nd6_dad_duplicated(ifa);
