The statically configured (permanent) ARP entries are removed when an

interface is brought down, even though the interface address is still
valid. This patch maintains the permanent ARP entries as long as the
interface address (having the same prefix as that of the ARP entries)
is valid.

Reviewed by:	delphij
MFC after:	5 days

3 files changed, 33 insertions, 18 deletions

diff --git a/sys/netinet/in.c b/sys/netinet/in.c
index 1012012..684d808 100644
--- a/sys/netinet/in.c
+++ b/sys/netinet/in.c
@@ -70,7 +70,7 @@ static int in_lifaddr_ioctl(struct socket *, u_long, caddr_t,
 	struct ifnet *, struct thread *);
 
 static int	in_addprefix(struct in_ifaddr *, int);
-static int	in_scrubprefix(struct in_ifaddr *);
+static int	in_scrubprefix(struct in_ifaddr *, u_int);
 static void	in_socktrim(struct sockaddr_in *);
 static int	in_ifinit(struct ifnet *,
 	    struct in_ifaddr *, struct sockaddr_in *, int);
@@ -548,7 +548,7 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 			 * is the same as before, then the call is 
 			 * un-necessarily executed here.
 			 */
-			in_ifscrub(ifp, ia);
+			in_ifscrub(ifp, ia, 0);
 			ia->ia_sockmask = ifra->ifra_mask;
 			ia->ia_sockmask.sin_family = AF_INET;
 			ia->ia_subnetmask =
@@ -557,7 +557,7 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 		}
 		if ((ifp->if_flags & IFF_POINTOPOINT) &&
 		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
-			in_ifscrub(ifp, ia);
+			in_ifscrub(ifp, ia, 0);
 			ia->ia_dstaddr = ifra->ifra_dstaddr;
 			maskIsNew  = 1; /* We lie; but the effect's the same */
 		}
@@ -585,7 +585,7 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 		/*
 		 * in_ifscrub kills the interface route.
 		 */
-		in_ifscrub(ifp, ia);
+		in_ifscrub(ifp, ia, LLE_STATIC);
 
 		/*
 		 * in_ifadown gets rid of all the rest of
@@ -829,10 +829,10 @@ in_lifaddr_ioctl(struct socket *so, u_long cmd, caddr_t data,
  * Delete any existing route for an interface.
  */
 void
-in_ifscrub(struct ifnet *ifp, struct in_ifaddr *ia)
+in_ifscrub(struct ifnet *ifp, struct in_ifaddr *ia, u_int flags)
 {
 
-	in_scrubprefix(ia);
+	in_scrubprefix(ia, flags);
 }
 
 /*
@@ -887,7 +887,7 @@ in_ifinit(struct ifnet *ifp, struct in_ifaddr *ia, struct sockaddr_in *sin,
 	splx(s);
 	if (scrub) {
 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
-		in_ifscrub(ifp, ia);
+		in_ifscrub(ifp, ia, LLE_STATIC);
 		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
 	}
 	if (IN_CLASSA(i))
@@ -1095,7 +1095,7 @@ extern void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
  * otherwise.
  */
 static int
-in_scrubprefix(struct in_ifaddr *target)
+in_scrubprefix(struct in_ifaddr *target, u_int flags)
 {
 	struct in_ifaddr *ia;
 	struct in_addr prefix, mask, p;
@@ -1130,13 +1130,15 @@ in_scrubprefix(struct in_ifaddr *target)
 				RT_REMREF(ia_ro.ro_rt);
 			RTFREE_LOCKED(ia_ro.ro_rt);
 		}
-		if (freeit)
+		if (freeit && (flags & LLE_STATIC)) {
 			error = ifa_del_loopback_route((struct ifaddr *)target,
 				       (struct sockaddr *)&target->ia_addr);
-		if (error == 0)
-			target->ia_flags &= ~IFA_RTSELF;
-		/* remove arp cache */
-		arp_ifscrub(target->ia_ifp, IA_SIN(target)->sin_addr.s_addr);
+			if (error == 0)
+				target->ia_flags &= ~IFA_RTSELF;
+		}
+		if (flags & LLE_STATIC)
+			/* remove arp cache */
+			arp_ifscrub(target->ia_ifp, IA_SIN(target)->sin_addr.s_addr);
 	}
 
 	if (rtinitflags(target))
@@ -1203,7 +1205,7 @@ in_scrubprefix(struct in_ifaddr *target)
 	mask0.sin_family = AF_INET;
 	mask0.sin_addr.s_addr = target->ia_subnetmask;
 	lltable_prefix_free(AF_INET, (struct sockaddr *)&prefix0, 
-			    (struct sockaddr *)&mask0);
+			    (struct sockaddr *)&mask0, flags);
 
 	/*
 	 * As no-one seem to have this prefix, we can remove the route.
@@ -1362,7 +1364,8 @@ in_lltable_free(struct lltable *llt, struct llentry *lle)
 static void
 in_lltable_prefix_free(struct lltable *llt, 
 		       const struct sockaddr *prefix,
-		       const struct sockaddr *mask)
+		       const struct sockaddr *mask,
+		       u_int flags)
 {
 	const struct sockaddr_in *pfx = (const struct sockaddr_in *)prefix;
 	const struct sockaddr_in *msk = (const struct sockaddr_in *)mask;
@@ -1373,8 +1376,13 @@ in_lltable_prefix_free(struct lltable *llt,
 	for (i=0; i < LLTBL_HASHTBL_SIZE; i++) {
 		LIST_FOREACH_SAFE(lle, &llt->lle_head[i], lle_next, next) {
 
+		        /* 
+			 * (flags & LLE_STATIC) means deleting all entries
+			 * including static ARP entries
+			 */
 			if (IN_ARE_MASKED_ADDR_EQUAL((struct sockaddr_in *)L3_ADDR(lle), 
-						     pfx, msk)) {
+						     pfx, msk) &&
+			    ((flags & LLE_STATIC) || !(lle->la_flags & LLE_STATIC))) {
 				int canceled;
 
 				canceled = callout_drain(&lle->la_timer);
diff --git a/sys/netinet/in_var.h b/sys/netinet/in_var.h
index cd1d904..5be07c1 100644
--- a/sys/netinet/in_var.h
+++ b/sys/netinet/in_var.h
@@ -447,7 +447,7 @@ int	in_control(struct socket *, u_long, caddr_t, struct ifnet *,
 void	in_rtqdrain(void);
 void	ip_input(struct mbuf *);
 int	in_ifadown(struct ifaddr *ifa, int);
-void	in_ifscrub(struct ifnet *, struct in_ifaddr *);
+void	in_ifscrub(struct ifnet *, struct in_ifaddr *, u_int);
 struct	mbuf	*ip_fastforward(struct mbuf *);
 void	*in_domifattach(struct ifnet *);
 void	in_domifdetach(struct ifnet *, void *);
diff --git a/sys/netinet/raw_ip.c b/sys/netinet/raw_ip.c
index b196de2..be099a8 100644
--- a/sys/netinet/raw_ip.c
+++ b/sys/netinet/raw_ip.c
@@ -64,6 +64,7 @@ __FBSDID("$FreeBSD$");
 #include <netinet/in_systm.h>
 #include <netinet/in_pcb.h>
 #include <netinet/in_var.h>
+#include <netinet/if_ether.h>
 #include <netinet/ip.h>
 #include <netinet/ip_var.h>
 #include <netinet/ip_mroute.h>
@@ -721,7 +722,7 @@ rip_ctlinput(int cmd, struct sockaddr *sa, void *vip)
 				/*
 				 * in_ifscrub kills the interface route.
 				 */
-				in_ifscrub(ia->ia_ifp, ia);
+				in_ifscrub(ia->ia_ifp, ia, 0);
 				/*
 				 * in_ifadown gets rid of all the rest of the
 				 * routes.  This is not quite the right thing
@@ -756,12 +757,18 @@ rip_ctlinput(int cmd, struct sockaddr *sa, void *vip)
 		    || (ifp->if_flags & IFF_POINTOPOINT))
 			flags |= RTF_HOST;
 
+		err = ifa_del_loopback_route((struct ifaddr *)ia, sa);
+		if (err == 0)
+			ia->ia_flags &= ~IFA_RTSELF;
+
 		err = rtinit(&ia->ia_ifa, RTM_ADD, flags);
 		if (err == 0)
 			ia->ia_flags |= IFA_ROUTE;
+
 		err = ifa_add_loopback_route((struct ifaddr *)ia, sa);
 		if (err == 0)
 			ia->ia_flags |= IFA_RTSELF;
+
 		ifa_free(&ia->ia_ifa);
 		break;
 	}