Pull up following revision(s) (requested by ozaki-r in ticket #1154):

	sys/net/nd.c: revision 1.8
	tests/net/arp/t_arp.sh: revision 1.49

nd: fix the number of requests for address resolution

ARP is expected to send requests for address resolution
net.inet.arp.nd_bmaxtries times at most.  However, it sends
one more.  IPv6 ND also behaves the same way.

The fix requires nd_set_timer reorganization to handle
scheduling timer without sending an NS message.
PR kern/59596

tests: add tests for ARP address resolution

Author: MartinHusemann

sys/net/nd.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: nd.c,v 1.5.2.1 2024/09/11 16:18:36 martin Exp $	*/
+/*	$NetBSD: nd.c,v 1.5.2.2 2025/08/29 15:21:16 martin Exp $	*/
 
 /*
  * Copyright (c) 2020 The NetBSD Foundation, Inc.
@@ -28,7 +28,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nd.c,v 1.5.2.1 2024/09/11 16:18:36 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd.c,v 1.5.2.2 2025/08/29 15:21:16 martin Exp $");
 
 #include <sys/callout.h>
 #include <sys/mbuf.h>
@@ -85,9 +85,11 @@ nd_timer(void *arg)
 		break;
 
 	case ND_LLINFO_INCOMPLETE:
-		send_ns = true;
-		if (ln->ln_asked++ < nd->nd_mmaxtries)
+		if (ln->ln_asked < nd->nd_mmaxtries) {
+			ln->ln_asked++;
+			send_ns = true;
 			break;
+		}
 
 		if (ln->ln_hold) {
 			struct mbuf *m0, *mnxt;
@@ -116,10 +118,8 @@ nd_timer(void *arg)
 		break;
 
 	case ND_LLINFO_REACHABLE:
-		if (!ND_IS_LLINFO_PERMANENT(ln)) {
+		if (!ND_IS_LLINFO_PERMANENT(ln))
 			ln->ln_state = ND_LLINFO_STALE;
-			nd_set_timer(ln, ND_TIMER_GC);
-		}
 		break;
 
 	case ND_LLINFO_PURGE: /* FALLTHROUGH */
@@ -137,10 +137,8 @@ nd_timer(void *arg)
 			ln->ln_state = ND_LLINFO_PROBE;
 			send_ns = true;
 			daddrp = &taddr;
-		} else {
+		} else
 			ln->ln_state = ND_LLINFO_STALE;
-			nd_set_timer(ln, ND_TIMER_GC);
-		}
 		break;
 
 	case ND_LLINFO_PROBE:
@@ -180,14 +178,18 @@ nd_timer(void *arg)
 		break;
 	}
 
+	if (ln != NULL) {
+		int type = ND_TIMER_RETRANS;
+		if (ln->ln_state == ND_LLINFO_WAITDELETE)
+			type = ND_TIMER_RETRANS_BACKOFF;
+		else if (ln->ln_state == ND_LLINFO_STALE)
+			type = ND_TIMER_GC;
+		nd_set_timer(ln, type);
+	}
 	if (send_ns) {
 		uint8_t lladdr[255], *lladdrp;
 		union l3addr src, *psrc;
 
-		if (ln->ln_state == ND_LLINFO_WAITDELETE)
-			nd_set_timer(ln, ND_TIMER_RETRANS_BACKOFF);
-		else
-			nd_set_timer(ln, ND_TIMER_RETRANS);
 		if (ln->ln_state > ND_LLINFO_INCOMPLETE &&
 		    ln->la_flags & LLE_VALID)
 		{

tests/net/arp/t_arp.sh

@@ -1,4 +1,4 @@
-#	$NetBSD: t_arp.sh,v 1.45.6.2 2024/09/13 14:17:26 martin Exp $
+#	$NetBSD: t_arp.sh,v 1.45.6.3 2025/08/29 15:21:16 martin Exp $
 #
 # Copyright (c) 2015 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -871,6 +871,42 @@ test_cache_creation_nodad()
 	test_cache_creation_common true
 }
 
+test_arp_request_count()
+{
+
+	export RUMP_SERVER=$SOCKSRC
+	pkt=$(make_pkt_str_arpreq 10.0.1.2 10.0.1.1)
+
+	extract_new_packets bus1 > ./out
+	atf_check -s not-exit:0 -o ignore -e ignore rump.ping -n -c 1 $IP4DST
+	extract_new_packets bus1 > ./out
+
+	# ARP sends request packets net.inet.arp.nd_bmaxtries times at most.
+	times=$(rump.sysctl -n net.inet.arp.nd_bmaxtries)
+	$DEBUG && echo times=$times
+	$DEBUG && cat ./out
+	atf_check -s exit:0 -o match:"$pkt" cat ./out
+	atf_check -s exit:0 -o match:"$times" sh -c "grep -E '$pkt' ./out |wc -l"
+}
+
+test_resolution()
+{
+
+	rump_server_start $SOCKSRC
+	setup_src_server
+
+	export RUMP_SERVER=$SOCKSRC
+
+	# Test default value of net.inet.arp.nd_bmaxtries
+	test_arp_request_count
+
+	# Test net.inet.arp.nd_bmaxtries=1
+	atf_check -s exit:0 rump.sysctl -wq net.inet.arp.nd_bmaxtries=1
+	test_arp_request_count
+
+	rump_server_destroy_ifaces
+}
+
 add_test()
 {
 	local name=$1
@@ -910,4 +946,5 @@ atf_init_test_cases()
 	add_test stray_entries         "Tests if ARP entries are removed on route change"
 	add_test cache_creation        "Tests for ARP cache creation"
 	add_test cache_creation_nodad  "Tests for ARP cache creation without DAD"
+	add_test resolution            "Tests for ARP resolution"
 }