Introduce a per-VNET flag to enable/disable netisr prcessing on that VNET.

Add accessor functions to toggle the state per VNET.
The base system (vnet0) will always enable itself with the normal
registration. We will share the registered protocol handlers in all
VNETs minimising duplication and management.
Upon disabling netisr processing for a VNET drain the netisr queue from
packets for that VNET.

Update netisr consumers to (de)register on a per-VNET start/teardown using
VNET_SYS(UN)INIT functionality.

The change should be transparent for non-VIMAGE kernels.

Reviewed by:	gnn (, hiren)
Obtained from:	projects/vnet
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D6691

5 files changed, 200 insertions, 6 deletions

diff --git a/sys/net/if_epair.c b/sys/net/if_epair.c
index 943776c..949a417 100644
--- a/sys/net/if_epair.c
+++ b/sys/net/if_epair.c
@@ -959,6 +959,9 @@ vnet_epair_init(const void *unused __unused)
 
 	V_epair_cloner = if_clone_advanced(epairname, 0,
 	    epair_clone_match, epair_clone_create, epair_clone_destroy);
+#ifdef VIMAGE
+	netisr_register_vnet(&epair_nh);
+#endif
 }
 VNET_SYSINIT(vnet_epair_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
     vnet_epair_init, NULL);
@@ -967,6 +970,9 @@ static void
 vnet_epair_uninit(const void *unused __unused)
 {
 
+#ifdef VIMAGE
+	netisr_unregister_vnet(&epair_nh);
+#endif
 	if_clone_detach(V_epair_cloner);
 }
 VNET_SYSUNINIT(vnet_epair_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index 9346aec..2542ab6 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -702,12 +702,16 @@ vnet_ether_init(__unused void *arg)
 	if ((i = pfil_head_register(&V_link_pfil_hook)) != 0)
 		printf("%s: WARNING: unable to register pfil link hook, "
 			"error %d\n", __func__, i);
+#ifdef VIMAGE
+	netisr_register_vnet(&ether_nh);
+#endif
 }
 VNET_SYSINIT(vnet_ether_init, SI_SUB_PROTO_IF, SI_ORDER_ANY,
     vnet_ether_init, NULL);
  
+#ifdef VIMAGE
 static void
-vnet_ether_destroy(__unused void *arg)
+vnet_ether_pfil_destroy(__unused void *arg)
 {
 	int i;
 
@@ -715,8 +719,18 @@ vnet_ether_destroy(__unused void *arg)
 		printf("%s: WARNING: unable to unregister pfil link hook, "
 			"error %d\n", __func__, i);
 }
+VNET_SYSUNINIT(vnet_ether_pfil_uninit, SI_SUB_PROTO_PFIL, SI_ORDER_ANY,
+    vnet_ether_pfil_destroy, NULL);
+
+static void
+vnet_ether_destroy(__unused void *arg)
+{
+
+	netisr_unregister_vnet(&ether_nh);
+}
 VNET_SYSUNINIT(vnet_ether_uninit, SI_SUB_PROTO_IF, SI_ORDER_ANY,
     vnet_ether_destroy, NULL);
+#endif
 
 
 
@@ -740,7 +754,9 @@ ether_input(struct ifnet *ifp, struct mbuf *m)
 		 * so assert it is correct here.
 		 */
 		KASSERT(m->m_pkthdr.rcvif == ifp, ("%s: ifnet mismatch", __func__));
+		CURVNET_SET_QUIET(ifp->if_vnet);
 		netisr_dispatch(NETISR_ETHER, m);
+		CURVNET_RESTORE();
 		m = mn;
 	}
 }
diff --git a/sys/net/netisr.c b/sys/net/netisr.c
index 492a851..318e1a3 100644
--- a/sys/net/netisr.c
+++ b/sys/net/netisr.c
@@ -210,6 +210,23 @@ SYSCTL_UINT(_net_isr, OID_AUTO, maxprot, CTLFLAG_RD,
  */
 static struct netisr_proto	netisr_proto[NETISR_MAXPROT];
 
+#ifdef VIMAGE
+/*
+ * The netisr_enable array describes a per-VNET flag for registered
+ * protocols on whether this netisr is active in this VNET or not.
+ * netisr_register() will automatically enable the netisr for the
+ * default VNET and all currently active instances.
+ * netisr_unregister() will disable all active VNETs, including vnet0.
+ * Individual network stack instances can be enabled/disabled by the
+ * netisr_(un)register _vnet() functions.
+ * With this we keep the one netisr_proto per protocol but add a
+ * mechanism to stop netisr processing for vnet teardown.
+ * Apart from that we expect a VNET to always be enabled.
+ */
+static VNET_DEFINE(u_int,	netisr_enable[NETISR_MAXPROT]);
+#define	V_netisr_enable		VNET(netisr_enable)
+#endif
+
 /*
  * Per-CPU workstream data.  See netisr_internal.h for more details.
  */
@@ -352,6 +369,7 @@ sysctl_netisr_dispatch_policy(SYSCTL_HANDLER_ARGS)
 void
 netisr_register(const struct netisr_handler *nhp)
 {
+	VNET_ITERATOR_DECL(vnet_iter);
 	struct netisr_work *npwp;
 	const char *name;
 	u_int i, proto;
@@ -420,6 +438,22 @@ netisr_register(const struct netisr_handler *nhp)
 		bzero(npwp, sizeof(*npwp));
 		npwp->nw_qlimit = netisr_proto[proto].np_qlimit;
 	}
+
+#ifdef VIMAGE
+	/*
+	 * Test that we are in vnet0 and have a curvnet set.
+	 */
+	KASSERT(curvnet != NULL, ("%s: curvnet is NULL", __func__));
+	KASSERT(IS_DEFAULT_VNET(curvnet), ("%s: curvnet %p is not vnet0 %p",
+	    __func__, curvnet, vnet0));
+	VNET_LIST_RLOCK_NOSLEEP();
+	VNET_FOREACH(vnet_iter) {
+		CURVNET_SET(vnet_iter);
+		V_netisr_enable[proto] = 1;
+		CURVNET_RESTORE();
+	}
+	VNET_LIST_RUNLOCK_NOSLEEP();
+#endif
 	NETISR_WUNLOCK();
 }
 
@@ -584,6 +618,7 @@ netisr_drain_proto(struct netisr_work *npwp)
 void
 netisr_unregister(const struct netisr_handler *nhp)
 {
+	VNET_ITERATOR_DECL(vnet_iter);
 	struct netisr_work *npwp;
 #ifdef INVARIANTS
 	const char *name;
@@ -602,6 +637,16 @@ netisr_unregister(const struct netisr_handler *nhp)
 	    ("%s(%u): protocol not registered for %s", __func__, proto,
 	    name));
 
+#ifdef VIMAGE
+	VNET_LIST_RLOCK_NOSLEEP();
+	VNET_FOREACH(vnet_iter) {
+		CURVNET_SET(vnet_iter);
+		V_netisr_enable[proto] = 0;
+		CURVNET_RESTORE();
+	}
+	VNET_LIST_RUNLOCK_NOSLEEP();
+#endif
+
 	netisr_proto[proto].np_name = NULL;
 	netisr_proto[proto].np_handler = NULL;
 	netisr_proto[proto].np_m2flow = NULL;
@@ -616,6 +661,97 @@ netisr_unregister(const struct netisr_handler *nhp)
 	NETISR_WUNLOCK();
 }
 
+#ifdef VIMAGE
+void
+netisr_register_vnet(const struct netisr_handler *nhp)
+{
+	u_int proto;
+
+	proto = nhp->nh_proto;
+
+	KASSERT(curvnet != NULL, ("%s: curvnet is NULL", __func__));
+	KASSERT(proto < NETISR_MAXPROT,
+	    ("%s(%u): protocol too big for %s", __func__, proto, nhp->nh_name));
+	NETISR_WLOCK();
+	KASSERT(netisr_proto[proto].np_handler != NULL,
+	    ("%s(%u): protocol not registered for %s", __func__, proto,
+	    nhp->nh_name));
+	
+	V_netisr_enable[proto] = 1;
+	NETISR_WUNLOCK();
+}
+
+static void
+netisr_drain_proto_vnet(struct vnet *vnet, u_int proto)
+{
+	struct netisr_workstream *nwsp;
+	struct netisr_work *npwp;
+	struct mbuf *m, *mp, *n, *ne;
+	u_int i;
+
+	KASSERT(vnet != NULL, ("%s: vnet is NULL", __func__));
+	NETISR_LOCK_ASSERT();
+
+	CPU_FOREACH(i) {
+		nwsp = DPCPU_ID_PTR(i, nws);
+		if (nwsp->nws_intr_event == NULL)
+			continue;
+		npwp = &nwsp->nws_work[proto];
+		NWS_LOCK(nwsp);
+
+		/*
+		 * Rather than dissecting and removing mbufs from the middle
+		 * of the chain, we build a new chain if the packet stays and
+		 * update the head and tail pointers at the end.  All packets
+		 * matching the given vnet are freed.
+		 */
+		m = npwp->nw_head;
+		n = ne = NULL;
+		while (m != NULL) {
+			mp = m;
+			m = m->m_nextpkt;
+			mp->m_nextpkt = NULL;
+			if (mp->m_pkthdr.rcvif->if_vnet != vnet) {
+				if (n == NULL) {
+					n = ne = mp;
+				} else {
+					ne->m_nextpkt = mp;
+					ne = mp;
+				}
+				continue;
+			}
+			/* This is a packet in the selected vnet. Free it. */
+			npwp->nw_len--;
+			m_freem(mp);
+		}
+		npwp->nw_head = n;
+		npwp->nw_tail = ne;
+		NWS_UNLOCK(nwsp);
+	}
+}
+
+void
+netisr_unregister_vnet(const struct netisr_handler *nhp)
+{
+	u_int proto;
+
+	proto = nhp->nh_proto;
+
+	KASSERT(curvnet != NULL, ("%s: curvnet is NULL", __func__));
+	KASSERT(proto < NETISR_MAXPROT,
+	    ("%s(%u): protocol too big for %s", __func__, proto, nhp->nh_name));
+	NETISR_WLOCK();
+	KASSERT(netisr_proto[proto].np_handler != NULL,
+	    ("%s(%u): protocol not registered for %s", __func__, proto,
+	    nhp->nh_name));
+	
+	V_netisr_enable[proto] = 0;
+
+	netisr_drain_proto_vnet(curvnet, proto);
+	NETISR_WUNLOCK();
+}
+#endif
+
 /*
  * Compose the global and per-protocol policies on dispatch, and return the
  * dispatch policy to use.
@@ -906,6 +1042,13 @@ netisr_queue_src(u_int proto, uintptr_t source, struct mbuf *m)
 	KASSERT(netisr_proto[proto].np_handler != NULL,
 	    ("%s: invalid proto %u", __func__, proto));
 
+#ifdef VIMAGE
+	if (V_netisr_enable[proto] == 0) {
+		m_freem(m);
+		return (ENOPROTOOPT);
+	}
+#endif
+
 	m = netisr_select_cpuid(&netisr_proto[proto], NETISR_DISPATCH_DEFERRED,
 	    source, m, &cpuid);
 	if (m != NULL) {
@@ -952,6 +1095,13 @@ netisr_dispatch_src(u_int proto, uintptr_t source, struct mbuf *m)
 	KASSERT(npp->np_handler != NULL, ("%s: invalid proto %u", __func__,
 	    proto));
 
+#ifdef VIMAGE
+	if (V_netisr_enable[proto] == 0) {
+		m_freem(m);
+		return (ENOPROTOOPT);
+	}
+#endif
+
 	dispatch_policy = netisr_get_dispatch(npp);
 	if (dispatch_policy == NETISR_DISPATCH_DEFERRED)
 		return (netisr_queue_src(proto, source, m));
diff --git a/sys/net/netisr.h b/sys/net/netisr.h
index 94a6cc4..63764a7 100644
--- a/sys/net/netisr.h
+++ b/sys/net/netisr.h
@@ -210,6 +210,10 @@ void	netisr_getqlimit(const struct netisr_handler *nhp, u_int *qlimitp);
 void	netisr_register(const struct netisr_handler *nhp);
 int	netisr_setqlimit(const struct netisr_handler *nhp, u_int qlimit);
 void	netisr_unregister(const struct netisr_handler *nhp);
+#ifdef VIMAGE
+void	netisr_register_vnet(const struct netisr_handler *nhp);
+void	netisr_unregister_vnet(const struct netisr_handler *nhp);
+#endif
 
 /*
  * Process a packet destined for a protocol, and attempt direct dispatch.
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index c074603..91158b0 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -191,15 +191,33 @@ SYSCTL_PROC(_net_route, OID_AUTO, netisr_maxqlen, CTLTYPE_INT|CTLFLAG_RW,
     "maximum routing socket dispatch queue length");
 
 static void
-rts_init(void)
+vnet_rts_init(void)
 {
 	int tmp;
 
-	if (TUNABLE_INT_FETCH("net.route.netisr_maxqlen", &tmp))
-		rtsock_nh.nh_qlimit = tmp;
-	netisr_register(&rtsock_nh);
+	if (IS_DEFAULT_VNET(curvnet)) {
+		if (TUNABLE_INT_FETCH("net.route.netisr_maxqlen", &tmp))
+			rtsock_nh.nh_qlimit = tmp;
+		netisr_register(&rtsock_nh);
+	}
+#ifdef VIMAGE
+	 else
+		netisr_register_vnet(&rtsock_nh);
+#endif
+}
+VNET_SYSINIT(vnet_rtsock, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD,
+    vnet_rts_init, 0);
+
+#ifdef VIMAGE
+static void
+vnet_rts_uninit(void)
+{
+
+	netisr_unregister_vnet(&rtsock_nh);
 }
-SYSINIT(rtsock, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rts_init, 0);
+VNET_SYSUNINIT(vnet_rts_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD,
+    vnet_rts_uninit, 0);
+#endif
 
 static int
 raw_input_rts_cb(struct mbuf *m, struct sockproto *proto, struct sockaddr *src,