Mechanical cleanup of epoch(9) usage in network stack.

- Remove macros that covertly create epoch_tracker on thread stack. Such
  macros a quite unsafe, e.g. will produce a buggy code if same macro is
  used in embedded scopes. Explicitly declare epoch_tracker always.

- Unmask interface list IFNET_RLOCK_NOSLEEP(), interface address list
  IF_ADDR_RLOCK() and interface AF specific data IF_AFDATA_RLOCK() read
  locking macros to what they actually are - the net_epoch.
  Keeping them as is is very misleading. They all are named FOO_RLOCK(),
  while they no longer have lock semantics. Now they allow recursion and
  what's more important they now no longer guarantee protection against
  their companion WLOCK macros.
  Note: INP_HASH_RLOCK() has same problems, but not touched by this commit.

This is non functional mechanical change. The only functionally changed
functions are ni6_addrs() and ni6_store_addrs(), where we no longer enter
epoch recursively.

Discussed with:	jtl, gallatin

1 files changed, 25 insertions, 17 deletions

diff --git a/sys/netinet/igmp.c b/sys/netinet/igmp.c
index 27c478382ef3..beb0f98209be 100644
--- a/sys/netinet/igmp.c
+++ b/sys/netinet/igmp.c
@@ -692,6 +692,7 @@ static int
 igmp_input_v1_query(struct ifnet *ifp, const struct ip *ip,
     const struct igmp *igmp)
 {
+	struct epoch_tracker	 et;
 	struct ifmultiaddr	*ifma;
 	struct igmp_ifsoftc	*igi;
 	struct in_multi		*inm;
@@ -733,7 +734,7 @@ igmp_input_v1_query(struct ifnet *ifp, const struct ip *ip,
 	 * for the interface on which the query arrived,
 	 * except those which are already running.
 	 */
-	IF_ADDR_RLOCK(ifp);
+	NET_EPOCH_ENTER(et);
 	CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
 		if (ifma->ifma_addr->sa_family != AF_INET ||
 		    ifma->ifma_protospec == NULL)
@@ -761,7 +762,7 @@ igmp_input_v1_query(struct ifnet *ifp, const struct ip *ip,
 			break;
 		}
 	}
-	IF_ADDR_RUNLOCK(ifp);
+	NET_EPOCH_EXIT(et);
 
 out_locked:
 	IGMP_UNLOCK();
@@ -777,6 +778,7 @@ static int
 igmp_input_v2_query(struct ifnet *ifp, const struct ip *ip,
     const struct igmp *igmp)
 {
+	struct epoch_tracker	 et;
 	struct ifmultiaddr	*ifma;
 	struct igmp_ifsoftc	*igi;
 	struct in_multi		*inm;
@@ -834,7 +836,7 @@ igmp_input_v2_query(struct ifnet *ifp, const struct ip *ip,
 		 */
 		CTR2(KTR_IGMPV3, "process v2 general query on ifp %p(%s)",
 		    ifp, ifp->if_xname);
-		IF_ADDR_RLOCK(ifp);
+		NET_EPOCH_ENTER(et);
 		CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
 			if (ifma->ifma_addr->sa_family != AF_INET ||
 			    ifma->ifma_protospec == NULL)
@@ -842,7 +844,7 @@ igmp_input_v2_query(struct ifnet *ifp, const struct ip *ip,
 			inm = (struct in_multi *)ifma->ifma_protospec;
 			igmp_v2_update_group(inm, timer);
 		}
-		IF_ADDR_RUNLOCK(ifp);
+		NET_EPOCH_EXIT(et);
 	} else {
 		/*
 		 * Group-specific IGMPv2 query, we need only
@@ -1218,11 +1220,13 @@ igmp_input_v1_report(struct ifnet *ifp, /*const*/ struct ip *ip,
 	 * Replace 0.0.0.0 with the subnet address if told to do so.
 	 */
 	if (V_igmp_recvifkludge && in_nullhost(ip->ip_src)) {
-		NET_EPOCH_ENTER();
+		struct epoch_tracker et;
+
+		NET_EPOCH_ENTER(et);
 		IFP_TO_IA(ifp, ia, &in_ifa_tracker);
 		if (ia != NULL)
 			ip->ip_src.s_addr = htonl(ia->ia_subnet);
-		NET_EPOCH_EXIT();
+		NET_EPOCH_EXIT(et);
 	}
 
 	CTR3(KTR_IGMPV3, "process v1 report 0x%08x on ifp %p(%s)",
@@ -1307,6 +1311,7 @@ igmp_input_v2_report(struct ifnet *ifp, /*const*/ struct ip *ip,
     /*const*/ struct igmp *igmp)
 {
 	struct rm_priotracker in_ifa_tracker;
+	struct epoch_tracker et;
 	struct in_ifaddr *ia;
 	struct in_multi *inm;
 
@@ -1315,23 +1320,23 @@ igmp_input_v2_report(struct ifnet *ifp, /*const*/ struct ip *ip,
 	 * leave requires knowing that we are the only member of a
 	 * group.
 	 */
-	NET_EPOCH_ENTER();
+	NET_EPOCH_ENTER(et);
 	IFP_TO_IA(ifp, ia, &in_ifa_tracker);
 	if (ia != NULL && in_hosteq(ip->ip_src, IA_SIN(ia)->sin_addr)) {
-		NET_EPOCH_EXIT();
+		NET_EPOCH_EXIT(et);
 		return (0);
 	}
 
 	IGMPSTAT_INC(igps_rcv_reports);
 
 	if (ifp->if_flags & IFF_LOOPBACK) {
-		NET_EPOCH_EXIT();
+		NET_EPOCH_EXIT(et);
 		return (0);
 	}
 
 	if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr)) ||
 	    !in_hosteq(igmp->igmp_group, ip->ip_dst)) {
-		NET_EPOCH_EXIT();
+		NET_EPOCH_EXIT(et);
 		IGMPSTAT_INC(igps_rcv_badreports);
 		return (EINVAL);
 	}
@@ -1347,7 +1352,7 @@ igmp_input_v2_report(struct ifnet *ifp, /*const*/ struct ip *ip,
 		if (ia != NULL)
 			ip->ip_src.s_addr = htonl(ia->ia_subnet);
 	}
-	NET_EPOCH_EXIT();
+	NET_EPOCH_EXIT(et);
 
 	CTR3(KTR_IGMPV3, "process v2 report 0x%08x on ifp %p(%s)",
 	     ntohl(igmp->igmp_group.s_addr), ifp, ifp->if_xname);
@@ -1989,6 +1994,7 @@ igmp_v3_cancel_link_timers(struct igmp_ifsoftc *igi)
 	struct ifnet		*ifp;
 	struct in_multi		*inm;
 	struct in_multi_head inm_free_tmp;
+	struct epoch_tracker et;
 
 	CTR3(KTR_IGMPV3, "%s: cancel v3 timers on ifp %p(%s)", __func__,
 	    igi->igi_ifp, igi->igi_ifp->if_xname);
@@ -2009,7 +2015,7 @@ igmp_v3_cancel_link_timers(struct igmp_ifsoftc *igi)
 	 * for all memberships scoped to this link.
 	 */
 	ifp = igi->igi_ifp;
-	IF_ADDR_RLOCK(ifp);
+	NET_EPOCH_ENTER(et);
 	CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
 		if (ifma->ifma_addr->sa_family != AF_INET ||
 		    ifma->ifma_protospec == NULL)
@@ -2054,7 +2060,7 @@ igmp_v3_cancel_link_timers(struct igmp_ifsoftc *igi)
 		inm->inm_timer = 0;
 		mbufq_drain(&inm->inm_scq);
 	}
-	IF_ADDR_RUNLOCK(ifp);
+	NET_EPOCH_EXIT(et);
 
 	inm_release_list_deferred(&inm_free_tmp);
 }
@@ -3297,6 +3303,7 @@ igmp_v3_merge_state_changes(struct in_multi *inm, struct mbufq *scq)
 static void
 igmp_v3_dispatch_general_query(struct igmp_ifsoftc *igi)
 {
+	struct epoch_tracker	 et;
 	struct ifmultiaddr	*ifma;
 	struct ifnet		*ifp;
 	struct in_multi		*inm;
@@ -3319,7 +3326,7 @@ igmp_v3_dispatch_general_query(struct igmp_ifsoftc *igi)
 
 	ifp = igi->igi_ifp;
 
-	IF_ADDR_RLOCK(ifp);
+	NET_EPOCH_ENTER(et);
 	CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
 		if (ifma->ifma_addr->sa_family != AF_INET ||
 		    ifma->ifma_protospec == NULL)
@@ -3350,7 +3357,7 @@ igmp_v3_dispatch_general_query(struct igmp_ifsoftc *igi)
 			break;
 		}
 	}
-	IF_ADDR_RUNLOCK(ifp);
+	NET_EPOCH_EXIT(et);
 
 send:
 	loop = (igi->igi_flags & IGIF_LOOPBACK) ? 1 : 0;
@@ -3522,13 +3529,14 @@ igmp_v3_encap_report(struct ifnet *ifp, struct mbuf *m)
 	ip->ip_src.s_addr = INADDR_ANY;
 
 	if (m->m_flags & M_IGMP_LOOP) {
+		struct epoch_tracker et;
 		struct in_ifaddr *ia;
 
-		NET_EPOCH_ENTER();
+		NET_EPOCH_ENTER(et);
 		IFP_TO_IA(ifp, ia, &in_ifa_tracker);
 		if (ia != NULL)
 			ip->ip_src = ia->ia_addr.sin_addr;
-		NET_EPOCH_EXIT();
+		NET_EPOCH_EXIT(et);
 	}
 
 	ip->ip_dst.s_addr = htonl(INADDR_ALLRPTS_GROUP);