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ip6mrouter: Make the expiration callout MPSAFE

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- Protect the `expire_upcalls` callout with the MFC6 mutex.  The callout
  handler needs this mutex anyway.
- Convert the MROUTER6 mutex to a sleepable sx lock.  It is only used
  when configuring the global v6 multicast routing socket, so is only
  used in system call paths where sleeping is safe.  This lets us drain
  the callout without having to drop the lock.
- For all locking macros in the file, convert to using a _LOCKPTR macro.

Reported by:	mav
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D31836
This commit is contained in:
Mark Johnston 2021-09-07 11:15:49 -04:00
parent eec892a845
commit 353783964c
1 changed files with 27 additions and 29 deletions
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56
sys/netinet6/ip6_mroute.c
View File

@ -167,16 +167,13 @@ SYSCTL_STRUCT(_net_inet6_ip6, OID_AUTO, mrt6stat, CTLFLAG_RW,
#define NO_RTE_FOUND 0x1
#define RTE_FOUND 0x2
static struct mtx mrouter6_mtx;
#define MROUTER6_LOCK() mtx_lock(&mrouter6_mtx)
#define MROUTER6_UNLOCK() mtx_unlock(&mrouter6_mtx)
#define MROUTER6_LOCK_ASSERT() do { \
mtx_assert(&mrouter6_mtx, MA_OWNED); \
NET_ASSERT_GIANT(); \
} while (0)
#define MROUTER6_LOCK_INIT() \
mtx_init(&mrouter6_mtx, "IPv6 multicast forwarding", NULL, MTX_DEF)
#define MROUTER6_LOCK_DESTROY() mtx_destroy(&mrouter6_mtx)
static struct sx mrouter6_mtx;
#define MROUTER6_LOCKPTR() (&mrouter6_mtx)
#define MROUTER6_LOCK() sx_xlock(MROUTER6_LOCKPTR())
#define MROUTER6_UNLOCK() sx_xunlock(MROUTER6_LOCKPTR())
#define MROUTER6_LOCK_ASSERT() sx_assert(MROUTER6_LOCKPTR(), SA_XLOCKED
#define MROUTER6_LOCK_INIT() sx_init(MROUTER6_LOCKPTR(), "mrouter6")
#define MROUTER6_LOCK_DESTROY() sx_destroy(MROUTER6_LOCKPTR())
static struct mf6c *mf6ctable[MF6CTBLSIZ];
SYSCTL_OPAQUE(_net_inet6_ip6, OID_AUTO, mf6ctable, CTLFLAG_RD,
@ -185,15 +182,14 @@ SYSCTL_OPAQUE(_net_inet6_ip6, OID_AUTO, mf6ctable, CTLFLAG_RD,
"netinet6/ip6_mroute.h)");
static struct mtx mfc6_mtx;
#define MFC6_LOCK() mtx_lock(&mfc6_mtx)
#define MFC6_UNLOCK() mtx_unlock(&mfc6_mtx)
#define MFC6_LOCK_ASSERT() do { \
mtx_assert(&mfc6_mtx, MA_OWNED); \
NET_ASSERT_GIANT(); \
} while (0)
#define MFC6_LOCK_INIT() \
mtx_init(&mfc6_mtx, "IPv6 multicast forwarding cache", NULL, MTX_DEF)
#define MFC6_LOCK_DESTROY() mtx_destroy(&mfc6_mtx)
#define MFC6_LOCKPTR() (&mfc6_mtx)
#define MFC6_LOCK() mtx_lock(MFC6_LOCKPTR())
#define MFC6_UNLOCK() mtx_unlock(MFC6_LOCKPTR())
#define MFC6_LOCK_ASSERT() mtx_assert(MFC6_LOCKPTR(), MA_OWNED)
#define MFC6_LOCK_INIT() mtx_init(MFC6_LOCKPTR(), \
"IPv6 multicast forwarding cache", \
NULL, MTX_DEF)
#define MFC6_LOCK_DESTROY() mtx_destroy(MFC6_LOCKPTR())
static u_char n6expire[MF6CTBLSIZ];
@ -230,12 +226,13 @@ SYSCTL_PROC(_net_inet6_ip6, OID_AUTO, mif6table,
"netinet6/ip6_mroute.h)");
static struct mtx mif6_mtx;
#define MIF6_LOCK() mtx_lock(&mif6_mtx)
#define MIF6_UNLOCK() mtx_unlock(&mif6_mtx)
#define MIF6_LOCK_ASSERT() mtx_assert(&mif6_mtx, MA_OWNED)
#define MIF6_LOCKPTR() (&mif6_mtx)
#define MIF6_LOCK() mtx_lock(MIF6_LOCKPTR())
#define MIF6_UNLOCK() mtx_unlock(MIF6_LOCKPTR())
#define MIF6_LOCK_ASSERT() mtx_assert(MIF6_LOCKPTR(), MA_OWNED)
#define MIF6_LOCK_INIT() \
mtx_init(&mif6_mtx, "IPv6 multicast interfaces", NULL, MTX_DEF)
#define MIF6_LOCK_DESTROY() mtx_destroy(&mif6_mtx)
mtx_init(MIF6_LOCKPTR(), "IPv6 multicast interfaces", NULL, MTX_DEF)
#define MIF6_LOCK_DESTROY() mtx_destroy(MIF6_LOCKPTR())
#ifdef MRT6DEBUG
VNET_DEFINE_STATIC(u_int, mrt6debug) = 0; /* debug level */
@ -583,11 +580,12 @@ ip6_mrouter_init(struct socket *so, int v, int cmd)
V_pim6 = 0;/* used for stubbing out/in pim stuff */
callout_init(&expire_upcalls_ch, 0);
callout_init_mtx(&expire_upcalls_ch, MFC6_LOCKPTR(), 0);
callout_reset(&expire_upcalls_ch, EXPIRE_TIMEOUT,
expire_upcalls, NULL);
MROUTER6_UNLOCK();
MRT6_DLOG(DEBUG_ANY, "finished");
return (0);
@ -626,8 +624,6 @@ X_ip6_mrouter_done(void)
V_pim6 = 0; /* used to stub out/in pim specific code */
callout_stop(&expire_upcalls_ch);
/*
* Free all multicast forwarding cache entries.
*/
@ -652,6 +648,8 @@ X_ip6_mrouter_done(void)
bzero((caddr_t)mf6ctable, sizeof(mf6ctable));
MFC6_UNLOCK();
callout_drain(&expire_upcalls_ch);
/*
* Reset register interface
*/
@ -1315,7 +1313,8 @@ expire_upcalls(void *unused)
struct mf6c *mfc, **nptr;
u_long i;
MFC6_LOCK();
MFC6_LOCK_ASSERT();
for (i = 0; i < MF6CTBLSIZ; i++) {
if (n6expire[i] == 0)
continue;
@ -1353,7 +1352,6 @@ expire_upcalls(void *unused)
}
}
}
MFC6_UNLOCK();
callout_reset(&expire_upcalls_ch, EXPIRE_TIMEOUT,
expire_upcalls, NULL);
}