Change the curvnet variable from a global const struct vnet *,

previously always pointing to the default vnet context, to a
dynamically changing thread-local one.  The currvnet context
should be set on entry to networking code via CURVNET_SET() macros,
and reverted to previous state via CURVNET_RESTORE().  Recursions
on curvnet are permitted, though strongly discuouraged.

This change should have no functional impact on nooptions VIMAGE
kernel builds, where CURVNET_* macros expand to whitespace.

The curthread->td_vnet (aka curvnet) variable's purpose is to be an
indicator of the vnet context in which the current network-related
operation takes place, in case we cannot deduce the current vnet
context from any other source, such as by looking at mbuf's
m->m_pkthdr.rcvif->if_vnet, sockets's so->so_vnet etc.  Moreover, so
far curvnet has turned out to be an invaluable consistency checking
aid: it helps to catch cases when sockets, ifnets or any other
vnet-aware structures may have leaked from one vnet to another.

The exact placement of the CURVNET_SET() / CURVNET_RESTORE() macros
was a result of an empirical iterative process, whith an aim to
reduce recursions on CURVNET_SET() to a minimum, while still reducing
the scope of CURVNET_SET() to networking only operations - the
alternative would be calling CURVNET_SET() on each system call entry.
In general, curvnet has to be set in three typicall cases: when
processing socket-related requests from userspace or from within the
kernel; when processing inbound traffic flowing from device drivers
to upper layers of the networking stack, and when executing
timer-driven networking functions.

This change also introduces a DDB subcommand to show the list of all
vnet instances.

Approved by:	julian (mentor)

1 files changed, 3 insertions, 3 deletions

diff --git a/sys/netinet/in_rmx.c b/sys/netinet/in_rmx.c
index 695f473..19cd5fb 100644
--- a/sys/netinet/in_rmx.c
+++ b/sys/netinet/in_rmx.c
@@ -250,14 +250,13 @@ static void in_rtqtimo_one(void *rock);
 static void
 in_rtqtimo(void *rock)
 {
+	CURVNET_SET((struct vnet *) rock);
 	INIT_VNET_NET(curvnet);
 	INIT_VNET_INET(curvnet);
 	int fibnum;
 	void *newrock;
 	struct timeval atv;
 
-	KASSERT((rock == (void *)V_rt_tables[0][AF_INET]),
-			("in_rtqtimo: unexpected arg"));
 	for (fibnum = 0; fibnum < rt_numfibs; fibnum++) {
 		if ((newrock = V_rt_tables[fibnum][AF_INET]) != NULL)
 			in_rtqtimo_one(newrock);
@@ -265,6 +264,7 @@ in_rtqtimo(void *rock)
 	atv.tv_usec = 0;
 	atv.tv_sec = V_rtq_timeout;
 	callout_reset(&V_rtq_timer, tvtohz(&atv), in_rtqtimo, rock);
+	CURVNET_RESTORE();
 }
 
 static void
@@ -377,7 +377,7 @@ in_inithead(void **head, int off)
 	rnh->rnh_close = in_clsroute;
 	if (_in_rt_was_here == 0 ) {
 		callout_init(&V_rtq_timer, CALLOUT_MPSAFE);
-		in_rtqtimo(rnh);	/* kick off timeout first time */
+		callout_reset(&V_rtq_timer, 1, in_rtqtimo, curvnet);
 		_in_rt_was_here = 1;
 	}
 	return 1;