bonding: add helper function bond_get_targets_ip(targets, ip)

Add function bond_get_targets_ip(targets, ip) which searches through
targets array of ips (arp_targets) and returns the position of first
match. If ip == 0, returns the first free slot. On failure to find the
ip or free slot, return -1.

Use it to verify if the arp we've received is valid and in sysfs.

v1->v2:
Fix "[2/6] bonding: add helper function bond_get_targets_ip(targets, ip)",
per Nikolay's advice, to verify if source ip != 0.0.0.0, otherwise we might
update 'null' arp_ip_targets' last_rx. Also, address style.

Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 3b31c19..976d28e 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2610,19 +2610,16 @@
 
 static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32 sip, __be32 tip)
 {
-	int i;
-	__be32 *targets = bond->params.arp_targets;
-
-	for (i = 0; (i < BOND_MAX_ARP_TARGETS) && targets[i]; i++) {
-		pr_debug("bva: sip %pI4 tip %pI4 t[%d] %pI4 bhti(tip) %d\n",
-			 &sip, &tip, i, &targets[i],
-			 bond_has_this_ip(bond, tip));
-		if (sip == targets[i]) {
-			if (bond_has_this_ip(bond, tip))
-				slave->last_arp_rx = jiffies;
-			return;
-		}
+	if (!sip || !bond_has_this_ip(bond, tip)) {
+		pr_debug("bva: sip %pI4 tip %pI4 not found\n", &sip, &tip);
+		return;
 	}
+
+	if (bond_get_targets_ip(bond->params.arp_targets, sip) == -1) {
+		pr_debug("bva: sip %pI4 not found in targets\n", &sip);
+		return;
+	}
+	slave->last_arp_rx = jiffies;
 }
 
 static int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond,
@@ -4839,7 +4836,7 @@
 
 	bond_create_proc_dir(bn);
 	bond_create_sysfs(bn);
-	
+
 	return 0;
 }