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, 11 insertions, 5 deletions

diff --git a/sys/netinet6/in6_rmx.c b/sys/netinet6/in6_rmx.c
index 3cc446878c57..70909b1fb0d2 100644
--- a/sys/netinet6/in6_rmx.c
+++ b/sys/netinet6/in6_rmx.c
@@ -289,8 +289,9 @@ static void
 in6_rtqtimo(void *rock)
 {
 	CURVNET_SET_QUIET((struct vnet *) rock);
+	INIT_VNET_NET(curvnet);
 	INIT_VNET_INET6(curvnet);
-	struct radix_node_head *rnh = rock;
+	struct radix_node_head *rnh = V_rt_tables[0][AF_INET6];
 	struct rtqk_arg arg;
 	struct timeval atv;
 	static time_t last_adjusted_timeout = 0;
@@ -376,8 +377,9 @@ static void
 in6_mtutimo(void *rock)
 {
 	CURVNET_SET_QUIET((struct vnet *) rock);
+	INIT_VNET_NET(curvnet);
 	INIT_VNET_INET6(curvnet);
-	struct radix_node_head *rnh = rock;
+	struct radix_node_head *rnh = V_rt_tables[0][AF_INET6];
 	struct mtuex_arg arg;
 	struct timeval atv;
 
@@ -403,7 +405,7 @@ void
 in6_rtqdrain(void)
 {
 	INIT_VNET_NET(curvnet);
-	struct radix_node_head *rnh = V_rt_tables[AF_INET6];
+	struct radix_node_head *rnh = V_rt_tables[0][AF_INET6];
 	struct rtqk_arg arg;
 
 	arg.found = arg.killed = 0;
@@ -427,6 +429,9 @@ in6_rtqdrain(void)
 int
 in6_inithead(void **head, int off)
 {
+#ifdef INVARIANTS
+	INIT_VNET_NET(curvnet);
+#endif
 	INIT_VNET_INET6(curvnet);
 	struct radix_node_head *rnh;
 
@@ -442,11 +447,12 @@ in6_inithead(void **head, int off)
 	V_rtq_timeout6 = RTQ_TIMEOUT;
 
 	rnh = *head;
+	KASSERT(rnh == V_rt_tables[0][AF_INET6], ("rnh?"));
 	rnh->rnh_addaddr = in6_addroute;
 	rnh->rnh_matchaddr = in6_matroute;
 	callout_init(&V_rtq_timer6, CALLOUT_MPSAFE);
-	in6_rtqtimo(rnh);	/* kick off timeout first time */
 	callout_init(&V_rtq_mtutimer, CALLOUT_MPSAFE);
-	in6_mtutimo(rnh);	/* kick off timeout first time */
+	in6_rtqtimo(curvnet);	/* kick off timeout first time */
+	in6_mtutimo(curvnet);	/* kick off timeout first time */
 	return 1;
 }