This patch fixes the following issues in the ARP operation:

1. There is a regression issue in the ARP code. The incomplete
   ARP entry was timing out too quickly (1 second timeout), as
   such, a new entry is created each time arpresolve() is called.
   Therefore the maximum attempts made is always 1. Consequently
   the error code returned to the application is always 0.
2. Set the expiration of each incomplete entry to a 20-second
   lifetime.
3. Return "incomplete" entries to the application.

Reviewed by:	kmacy
MFC after:	3 days

2 files changed, 18 insertions, 10 deletions

diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c
index be62921..45cee89 100644
--- a/sys/netinet/if_ether.c
+++ b/sys/netinet/if_ether.c
@@ -88,11 +88,14 @@ VNET_DEFINE(int, useloopback) = 1;	/* use loopback interface for
 /* timer values */
 static VNET_DEFINE(int, arpt_keep) = (20*60);	/* once resolved, good for 20
 						 * minutes */
+static VNET_DEFINE(int, arpt_down) = 20;      /* keep incomplete entries for
+					       * 20 seconds */
 static VNET_DEFINE(int, arp_maxtries) = 5;
 static VNET_DEFINE(int, arp_proxyall);
 static VNET_DEFINE(struct arpstat, arpstat);  /* ARP statistics, see if_arp.h */
 
 #define	V_arpt_keep		VNET(arpt_keep)
+#define	V_arpt_down		VNET(arpt_down)
 #define	V_arp_maxtries		VNET(arp_maxtries)
 #define	V_arp_proxyall		VNET(arp_proxyall)
 #define	V_arpstat		VNET(arpstat)
@@ -309,7 +312,7 @@ retry:
 	} 
 
 	if ((la->la_flags & LLE_VALID) &&
-	    ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
+	    ((la->la_flags & LLE_STATIC) || la->la_expire > time_second)) {
 		bcopy(&la->ll_addr, desten, ifp->if_addrlen);
 		/*
 		 * If entry has an expiry time and it is approaching,
@@ -317,7 +320,7 @@ retry:
 		 * arpt_down interval.
 		 */
 		if (!(la->la_flags & LLE_STATIC) &&
-		    time_uptime + la->la_preempt > la->la_expire) {
+		    time_second + la->la_preempt > la->la_expire) {
 			arprequest(ifp, NULL,
 			    &SIN(dst)->sin_addr, IF_LLADDR(ifp));
 
@@ -337,7 +340,7 @@ retry:
 		goto done;
 	}
 
-	renew = (la->la_asked == 0 || la->la_expire != time_uptime);
+	renew = (la->la_asked == 0 || la->la_expire != time_second);
 	if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
 		flags |= LLE_EXCLUSIVE;
 		LLE_RUNLOCK(la);
@@ -370,12 +373,12 @@ retry:
 		error = EWOULDBLOCK;	/* First request. */
 	else
 		error =
-		    (rt0->rt_flags & RTF_GATEWAY) ? EHOSTDOWN : EHOSTUNREACH;
+			(rt0->rt_flags & RTF_GATEWAY) ? EHOSTUNREACH : EHOSTDOWN;
 
 	if (renew) {
 		LLE_ADDREF(la);
-		la->la_expire = time_uptime;
-		callout_reset(&la->la_timer, hz, arptimer, la);
+		la->la_expire = time_second;
+		callout_reset(&la->la_timer, hz * V_arpt_down, arptimer, la);
 		la->la_asked++;
 		LLE_WUNLOCK(la);
 		arprequest(ifp, NULL, &SIN(dst)->sin_addr,
@@ -687,7 +690,7 @@ match:
 		EVENTHANDLER_INVOKE(arp_update_event, la);
 
 		if (!(la->la_flags & LLE_STATIC)) {
-			la->la_expire = time_uptime + V_arpt_keep;
+			la->la_expire = time_second + V_arpt_keep;
 			callout_reset(&la->la_timer, hz * V_arpt_keep,
 			    arptimer, la);
 		}
diff --git a/sys/netinet/in.c b/sys/netinet/in.c
index dc4a8e1..c124513 100644
--- a/sys/netinet/in.c
+++ b/sys/netinet/in.c
@@ -1440,7 +1440,7 @@ in_lltable_dump(struct lltable *llt, struct sysctl_req *wr)
 			struct sockaddr_dl *sdl;
 			
 			/* skip deleted entries */
-			if ((lle->la_flags & (LLE_DELETED|LLE_VALID)) != LLE_VALID)
+			if ((lle->la_flags & LLE_DELETED) == LLE_DELETED)
 				continue;
 			/* Skip if jailed and not a valid IP of the prison. */
 			if (prison_if(wr->td->td_ucred, L3_ADDR(lle)) != 0)
@@ -1472,10 +1472,15 @@ in_lltable_dump(struct lltable *llt, struct sysctl_req *wr)
 			sdl = &arpc.sdl;
 			sdl->sdl_family = AF_LINK;
 			sdl->sdl_len = sizeof(*sdl);
-			sdl->sdl_alen = ifp->if_addrlen;
 			sdl->sdl_index = ifp->if_index;
 			sdl->sdl_type = ifp->if_type;
-			bcopy(&lle->ll_addr, LLADDR(sdl), ifp->if_addrlen);
+			if ((lle->la_flags & LLE_VALID) == LLE_VALID) {
+				sdl->sdl_alen = ifp->if_addrlen;
+				bcopy(&lle->ll_addr, LLADDR(sdl), ifp->if_addrlen);
+			} else {
+				sdl->sdl_alen = 0;
+				bzero(LLADDR(sdl), ifp->if_addrlen);
+			}
 
 			arpc.rtm.rtm_rmx.rmx_expire =
 			    lle->la_flags & LLE_STATIC ? 0 : lle->la_expire;