bonding: arp_ip_count and arp_targets can be wrong

When getting arp_ip_targets if we encounter a bad IP, arp_ip_count still
gets increased and all the targets after the wrong one will not be probed
if arp_interval is enabled after that (unless a new IP target is added
through sysfs) because of the zero entry, in this case reading
arp_ip_target through sysfs will show valid targets even if there's a
zero entry.
Example: 1.2.3.4,4.5.6.7,blah,5.6.7.8
When retrieving the list from arp_ip_target the output would be:
1.2.3.4,4.5.6.7,5.6.7.8
but there will be a 0 entry between 4.5.6.7 and 5.6.7.8. If arp_interval
is enabled after that 5.6.7.8 will never be checked because of that.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 11 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index d4635987bda9..29b846cbfb48 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4471,7 +4471,7 @@ int bond_parse_parm(const char *buf, const struct bond_parm_tbl *tbl)
 
 static int bond_check_params(struct bond_params *params)
 {
-        int arp_validate_value, fail_over_mac_value, primary_reselect_value;
+        int arp_validate_value, fail_over_mac_value, primary_reselect_value, i;
 
         /*
          * Convert string parameters.
@@ -4651,19 +4651,18 @@ static int bond_check_params(struct bond_params *params)
                 arp_interval = BOND_LINK_ARP_INTERV;
         }
 
-        for (arp_ip_count = 0;
-             (arp_ip_count < BOND_MAX_ARP_TARGETS) && arp_ip_target[arp_ip_count];
-             arp_ip_count++) {
+        for (arp_ip_count = 0, i = 0;
+             (arp_ip_count < BOND_MAX_ARP_TARGETS) && arp_ip_target[i]; i++) {
                 /* not complete check, but should be good enough to
                    catch mistakes */
-                __be32 ip = in_aton(arp_ip_target[arp_ip_count]);
-                if (!isdigit(arp_ip_target[arp_ip_count][0]) ||
-                    ip == 0 || ip == htonl(INADDR_BROADCAST)) {
+                __be32 ip = in_aton(arp_ip_target[i]);
+                if (!isdigit(arp_ip_target[i][0]) || ip == 0 ||
+                    ip == htonl(INADDR_BROADCAST)) {
                         pr_warning("Warning: bad arp_ip_target module parameter (%s), ARP monitoring will not be performed\n",
-                                   arp_ip_target[arp_ip_count]);
+                                   arp_ip_target[i]);
                         arp_interval = 0;
                 } else {
-                        arp_target[arp_ip_count] = ip;
+                        arp_target[arp_ip_count++] = ip;
                 }
         }
 
@@ -4697,8 +4696,6 @@ static int bond_check_params(struct bond_params *params)
         if (miimon) {
                 pr_info("MII link monitoring set to %d ms\n", miimon);
         } else if (arp_interval) {
-                int i;
-
                 pr_info("ARP monitoring set to %d ms, validate %s, with %d target(s):",
                         arp_interval,
                         arp_validate_tbl[arp_validate_value].modename,