Subject: [PATCH net-next 6/6] bonding: add an option to fail when any of arp_ip_target is inaccessible

From: Veaceslav Falico <[email-masked]>
Date: Wed, 19 Jun 2013 19:34:46 +0200

Currently, we fail only when all of the ips in arp_ip_target are gone.
However, in some situations we might need to fail if even one host from
arp_ip_target becomes unavailable.

All situations, obviously, rely on the idea that we need *completely*
functional network, with all interfaces/addresses working correctly.

One real world example might be:
vlans on top on bond (hybrid port). If bond and vlans have ips assigned
and we have their peers monitored via arp_ip_target - in case of switch
misconfiguration (trunk/access port), slave driver malfunction or
tagged/untagged traffic dropped on the way - we will be able to switch
to another slave.

Though any other configuration needs that if we need to have access to all
arp_ip_targets.

This patch adds this possibility by adding a new parameter -
arp_all_targets (both as a module parameter and as a sysfs knob). It can be
set to:

	0 or any (the default) - which works exactly as it's working now -
	the slave is up if any of the arp_ip_targets are up.

	1 or all - the slave is up if all of the arp_ip_targets are up.

This parameter can be changed on the fly (via sysfs), and requires the mode
to be active-backup and arp_validate to be enabled (it obeys the
arp_validate config on which slaves to validate).

Internally it's done through:

1) Add target_last_arp_rx[BOND_MAX_ARP_TARGETS] array to slave struct. It's
   an array of jiffies, meaning that slave->target_last_arp_rx[i] is the
   last time we've received arp from bond->params.arp_targets[i] on this
   slave.

2) If we successfully validate an arp from bond->params.arp_targets[i] in
   bond_validate_arp() - update the slave->target_last_arp_rx[i] with the
   current jiffies value.

3) When getting slave's last_rx via slave_last_rx(), we return the oldest
   time when we've received an arp from any address in
   bond->params.arp_targets[].

If the value of arp_all_targets == 0 - we still work the same way as
before.

Also, update the documentation to reflect the new parameter.

Signed-off-by: Veaceslav Falico <[email-masked]>
---
 Documentation/networking/bonding.txt |   17 +++++++++++++
 drivers/net/bonding/bond_main.c      |   38 +++++++++++++++++++++++++++-
 drivers/net/bonding/bond_sysfs.c     |   44 ++++++++++++++++++++++++++++++++++
 drivers/net/bonding/bonding.h        |   30 +++++++++++++++++++++-
 4 files changed, 125 insertions(+), 4 deletions(-)

diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 84f16c8..284b4ab 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -309,6 +309,23 @@ arp_validate
 
 	This option was added in bonding version 3.1.0.
 
+arp_all_targets
+
+	Specifies whether, in active-backup mode with arp validation,
+	any of the arp_ip_targets should be up to keep the slave up
+	(default) or it should go down if at least one of
+	arp_ip_targets doesn't reply to arp requests.
+
+	Possible values are:
+
+	any or 0
+
+		consider the slave up if any of the arp_ip_targets is up
+
+	all or 1
+
+		consider the slave up if all of the arp_ip_targets are up
+
 downdelay
 
 	Specifies the time, in milliseconds, to wait before disabling
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 3f64607..6136e5e 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -104,6 +104,7 @@ static char *xmit_hash_policy;
 static int arp_interval = BOND_LINK_ARP_INTERV;
 static char *arp_ip_target[BOND_MAX_ARP_TARGETS];
 static char *arp_validate;
+static char *arp_all_targets;
 static char *fail_over_mac;
 static int all_slaves_active = 0;
 static struct bond_params bonding_defaults;
@@ -166,6 +167,8 @@ module_param(arp_validate, charp, 0);
 MODULE_PARM_DESC(arp_validate, "validate src/dst of ARP probes; "
 			       "0 for none (default), 1 for active, "
 			       "2 for backup, 3 for all");
+module_param(arp_all_targets, charp, 0);
+MODULE_PARM_DESC(arp_all_targets, "fail on any/all arp targets timeout; 0 for any (default), 1 for all");
 module_param(fail_over_mac, charp, 0);
 MODULE_PARM_DESC(fail_over_mac, "For active-backup, do not set all slaves to "
 				"the same MAC; 0 for none (default), "
@@ -216,6 +219,12 @@ const struct bond_parm_tbl xmit_hashtype_tbl[] = {
 {	NULL,			-1},
 };
 
+const struct bond_parm_tbl arp_all_targets_tbl[] = {
+{	"any",			BOND_ARP_TARGETS_ANY},
+{	"all",			BOND_ARP_TARGETS_ALL},
+{	NULL,			-1},
+};
+
 const struct bond_parm_tbl arp_validate_tbl[] = {
 {	"none",			BOND_ARP_VALIDATE_NONE},
 {	"active",		BOND_ARP_VALIDATE_ACTIVE},
@@ -1476,7 +1485,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	struct slave *new_slave = NULL;
 	struct sockaddr addr;
 	int link_reporting;
-	int res = 0;
+	int res = 0, i;
 
 	if (!bond->params.use_carrier &&
 	    slave_dev->ethtool_ops->get_link == NULL &&
@@ -1705,6 +1714,8 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 
 	new_slave->last_arp_rx = jiffies -
 		(msecs_to_jiffies(bond->params.arp_interval) + 1);
+	for (i = 0; i < BOND_MAX_ARP_TARGETS; i++)
+		new_slave->target_last_arp_rx[i] = jiffies;
 
 	if (bond->params.miimon && !bond->params.use_carrier) {
 		link_reporting = bond_check_dev_link(bond, slave_dev, 1);
@@ -2599,17 +2610,21 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 
 static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32 sip, __be32 tip)
 {
+	int i;
+
 	if (!bond_has_this_ip(bond, tip)) {
 		pr_debug("bva: tip %pI4 not found\n", &tip);
 		return;
 	}
 
-	if (bond_get_targets_ip(bond->params.arp_targets, sip) == -1) {
+	i = bond_get_targets_ip(bond->params.arp_targets, sip);
+	if (i == -1) {
 		pr_debug("bva: sip %pI4 not found in targets\n", &sip);
 		return;
 	}
 
 	slave->last_arp_rx = jiffies;
+	slave->target_last_arp_rx[i] = jiffies;
 }
 
 static int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond,
@@ -4381,6 +4396,7 @@ 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, i;
+	int arp_all_targets_value;
 
 	/*
 	 * Convert string parameters.
@@ -4606,6 +4622,23 @@ static int bond_check_params(struct bond_params *params)
 	} else
 		arp_validate_value = 0;
 
+	if (arp_all_targets) {
+		if (!arp_validate_value) {
+			pr_err("arp_all_targets requires arp_validate\n");
+			return -EINVAL;
+		}
+
+		arp_all_targets_value = bond_parse_parm(arp_all_targets,
+							arp_all_targets_tbl);
+
+		if (arp_all_targets_value == -1) {
+			pr_err("Error: invalid arp_all_targets_value \"%s\"\n",
+			       arp_all_targets);
+			return -EINVAL;
+		}
+	} else
+		arp_all_targets_value = 0;
+
 	if (miimon) {
 		pr_info("MII link monitoring set to %d ms\n", miimon);
 	} else if (arp_interval) {
@@ -4670,6 +4703,7 @@ static int bond_check_params(struct bond_params *params)
 	params->num_peer_notif = num_peer_notif;
 	params->arp_interval = arp_interval;
 	params->arp_validate = arp_validate_value;
+	params->arp_all_targets = arp_all_targets_value;
 	params->updelay = updelay;
 	params->downdelay = downdelay;
 	params->use_carrier = use_carrier;
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index e680151..09fb9f7 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -443,6 +443,49 @@ static ssize_t bonding_store_arp_validate(struct device *d,
 
 static DEVICE_ATTR(arp_validate, S_IRUGO | S_IWUSR, bonding_show_arp_validate,
 		   bonding_store_arp_validate);
+/*
+ * Show and set arp_all_targets.
+ */
+static ssize_t bonding_show_arp_all_targets(struct device *d,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct bonding *bond = to_bond(d);
+	int value = bond->params.arp_all_targets;
+
+	return sprintf(buf, "%s %d\n", arp_all_targets_tbl[value].modename,
+		       value);
+}
+
+static ssize_t bonding_store_arp_all_targets(struct device *d,
+					  struct device_attribute *attr,
+					  const char *buf, size_t count)
+{
+	int new_value;
+	struct bonding *bond = to_bond(d);
+
+	new_value = bond_parse_parm(buf, arp_all_targets_tbl);
+	if (new_value < 0) {
+		pr_err("%s: Ignoring invalid arp_all_targets value %s\n",
+		       bond->dev->name, buf);
+		return -EINVAL;
+	}
+	if (new_value && !bond->params.arp_validate) {
+		pr_err("%s: arp_all_targets requires arp_validate.\n",
+		       bond->dev->name);
+		return -EINVAL;
+	}
+	pr_info("%s: setting arp_all_targets to %s (%d).\n",
+		bond->dev->name, arp_all_targets_tbl[new_value].modename,
+		new_value);
+
+	bond->params.arp_all_targets = new_value;
+
+	return count;
+}
+
+static DEVICE_ATTR(arp_all_targets, S_IRUGO | S_IWUSR,
+		   bonding_show_arp_all_targets, bonding_store_arp_all_targets);
 
 /*
  * Show and store fail_over_mac.  User only allowed to change the
@@ -1625,6 +1668,7 @@ static struct attribute *per_bond_attrs[] = {
 	&dev_attr_mode.attr,
 	&dev_attr_fail_over_mac.attr,
 	&dev_attr_arp_validate.attr,
+	&dev_attr_arp_all_targets.attr,
 	&dev_attr_arp_interval.attr,
 	&dev_attr_arp_ip_target.attr,
 	&dev_attr_downdelay.attr,
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 7feab6c..29fc8d6 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -144,6 +144,7 @@ struct bond_params {
 	u8 num_peer_notif;
 	int arp_interval;
 	int arp_validate;
+	int arp_all_targets;
 	int use_carrier;
 	int fail_over_mac;
 	int updelay;
@@ -179,6 +180,7 @@ struct slave {
 	int    delay;
 	unsigned long jiffies;
 	unsigned long last_arp_rx;
+	unsigned long target_last_arp_rx[BOND_MAX_ARP_TARGETS];
 	s8     link;    /* one of BOND_LINK_XXXX */
 	s8     new_link;
 	u8     backup:1,   /* indicates backup slave. Value corresponds with
@@ -322,6 +324,9 @@ static inline bool bond_is_active_slave(struct slave *slave)
 #define BOND_FOM_ACTIVE			1
 #define BOND_FOM_FOLLOW			2
 
+#define BOND_ARP_TARGETS_ANY		0
+#define BOND_ARP_TARGETS_ALL		1
+
 #define BOND_ARP_VALIDATE_NONE		0
 #define BOND_ARP_VALIDATE_ACTIVE	(1 << BOND_STATE_ACTIVE)
 #define BOND_ARP_VALIDATE_BACKUP	(1 << BOND_STATE_BACKUP)
@@ -334,11 +339,31 @@ static inline int slave_do_arp_validate(struct bonding *bond,
 	return bond->params.arp_validate & (1 << bond_slave_state(slave));
 }
 
+/* Get the oldest arp which we've received on this slave for bond's
+ * arp_targets.
+ */
+static inline unsigned long slave_oldest_target_arp_rx(struct bonding *bond,
+						       struct slave *slave)
+{
+	int i = 1;
+	unsigned long ret = slave->target_last_arp_rx[0];
+
+	for (; (i < BOND_MAX_ARP_TARGETS) && bond->params.arp_targets[i]; i++)
+		if (time_before(slave->target_last_arp_rx[i], ret))
+			ret = slave->target_last_arp_rx[i];
+
+	return ret;
+}
+
 static inline unsigned long slave_last_rx(struct bonding *bond,
 					struct slave *slave)
 {
-	if (slave_do_arp_validate(bond, slave))
-		return slave->last_arp_rx;
+	if (slave_do_arp_validate(bond, slave)) {
+		if (bond->params.arp_all_targets == BOND_ARP_TARGETS_ALL)
+			return slave_oldest_target_arp_rx(bond, slave);
+		else
+			return slave->last_arp_rx;
+	}
 
 	return slave->dev->last_rx;
 }
@@ -486,6 +511,7 @@ extern const struct bond_parm_tbl bond_lacp_tbl[];
 extern const struct bond_parm_tbl bond_mode_tbl[];
 extern const struct bond_parm_tbl xmit_hashtype_tbl[];
 extern const struct bond_parm_tbl arp_validate_tbl[];
+extern const struct bond_parm_tbl arp_all_targets_tbl[];
 extern const struct bond_parm_tbl fail_over_mac_tbl[];
 extern const struct bond_parm_tbl pri_reselect_tbl[];
 extern struct bond_parm_tbl ad_select_tbl[];
-- 
1.7.1