[PATCH net-next] bonding: lacp_port_id setting for 802.3ad

[Krisztian Ivancso <github-ivan@ivancso.net>]

The patch adds port id setting feature by lacp_port_id module
parameter for 802.3ad ports.

Adding more linux boxes to a link aggregation makes possible to do
load-balancing by using port channel load balancing of switch
(eg. by source-dest-ip or src-ip).

It's essential to set the same MAC address to bonding interface and
to set different port ids on different linux boxes for a
working solution.

Possible use cases:
1. Redundant DNS servers with same IP address
2. Reverse proxies with same IP address
3. "multi-master" LVS

Beside redundancy it provides scalability, scalability depends on
hardware capability.
E.g. a LAG port with 4 members - linux LVS servers - using a Cisco
switch/router splits traffic to ports equally by src IP (2-2-2-2).
If a link fails, switch forwards traffic to 3 switch ports (3-3-3).
It means you can utilize overall bandwith as much as 66% with full
redundancy. It's better with 16% than using 2 master-slave LVS and
you use just 1 IP and can handle 100% more peak traffic.

Using this feature with vPC (virtual portchannel) or similar solution
it provides a physically redundant service from network devices
to servers using the same IP address.


>From 472fffa5a8f170daed9e4cc677af8e2560b86be2 Mon Sep 17 00:00:00 2001
From: Krisztian Ivancso <github-ivan@ivancso.net>
Date: Sun, 11 Aug 2013 20:30:44 +0200
Subject: [PATCH net-next] bonding: lacp_port_id setting for 802.3ad ports

By setting this parameter to different values on different hosts
it's possible to add more Linux boxes to the same Link Aggregation.

Signed-off-by: Krisztian Ivancso <github-ivan@ivancso.net>
---
 drivers/net/bonding/bond_main.c   | 18 ++++++++++++++++--
 drivers/net/bonding/bond_procfs.c |  1 +
 drivers/net/bonding/bond_sysfs.c  | 33 +++++++++++++++++++++++++++++++++
 drivers/net/bonding/bonding.h     |  1 +
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 4264a76..452f4d4 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -110,6 +110,7 @@ static char *fail_over_mac;
 static int all_slaves_active;
 static struct bond_params bonding_defaults;
 static int resend_igmp = BOND_DEFAULT_RESEND_IGMP;
+static int lacp_port_id = 1;

 module_param(max_bonds, int, 0);
 MODULE_PARM_DESC(max_bonds, "Max number of bonded devices");
@@ -150,7 +151,7 @@ module_param(lacp_rate, charp, 0);
 MODULE_PARM_DESC(lacp_rate, "LACPDU tx rate to request from 802.3ad partner; "
 			    "0 for slow, 1 for fast");
 module_param(ad_select, charp, 0);
-MODULE_PARM_DESC(ad_select, "803.ad aggregation selection logic; "
+MODULE_PARM_DESC(ad_select, "802.3ad aggregation selection logic; "
 			    "0 for stable (default), 1 for bandwidth, "
 			    "2 for count");
 module_param(min_links, int, 0);
@@ -181,6 +182,8 @@ MODULE_PARM_DESC(all_slaves_active, "Keep all frames received on an interface"
 module_param(resend_igmp, int, 0);
 MODULE_PARM_DESC(resend_igmp, "Number of IGMP membership reports to send on "
 			      "link failure");
+module_param(lacp_port_id, int, 0);
+MODULE_PARM_DESC(lacp_port_id, "802.3ad port id to send to switch in LACPDU");

 /*----------------------------- Global variables ----------------------------*/

@@ -1699,7 +1702,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 		bond_set_slave_inactive_flags(new_slave);
 		/* if this is the first slave */
 		if (bond_first_slave(bond) == new_slave) {
-			SLAVE_AD_INFO(new_slave).id = 1;
+			SLAVE_AD_INFO(new_slave).id = lacp_port_id;
 			/* Initialize AD with the number of times that the AD timer is called in 1 second
 			 * can be called only after the mac address of the bond is set
 			 */
@@ -4377,6 +4380,16 @@ static int bond_check_params(struct bond_params *params)
 		resend_igmp = BOND_DEFAULT_RESEND_IGMP;
 	}

+	if (bond_mode == BOND_MODE_8023AD) {
+		/* we set upper limit to 65000 because new slaves will increase port
+                   id so we don't want id to overflow */
+		if (lacp_port_id < 1 || lacp_port_id > 65000) {
+			pr_warning("Warning: lacp_port_id (%d) should be between "
+				   "1 and 65000, resetting to 1\n", lacp_port_id);
+			lacp_port_id = 1;
+		}
+	}
+
 	/* reset values for TLB/ALB */
 	if ((bond_mode == BOND_MODE_TLB) ||
 	    (bond_mode == BOND_MODE_ALB)) {
@@ -4565,6 +4578,7 @@ static int bond_check_params(struct bond_params *params)
 	params->all_slaves_active = all_slaves_active;
 	params->resend_igmp = resend_igmp;
 	params->min_links = min_links;
+	params->lacp_port_id = lacp_port_id;

 	if (primary) {
 		strncpy(params->primary, primary, IFNAMSIZ);
diff --git a/drivers/net/bonding/bond_procfs.c b/drivers/net/bonding/bond_procfs.c
index 20a6ee2..6d52716 100644
--- a/drivers/net/bonding/bond_procfs.c
+++ b/drivers/net/bonding/bond_procfs.c
@@ -129,6 +129,7 @@ static void bond_info_show_master(struct seq_file *seq)
 		seq_printf(seq, "Min links: %d\n", bond->params.min_links);
 		seq_printf(seq, "Aggregator selection policy (ad_select): %s\n",
 			   ad_select_tbl[bond->params.ad_select].modename);
+		seq_printf(seq, "802.3ad starting port id: %d\n", bond->params.lacp_port_id);

 		if (__bond_3ad_get_active_agg_info(bond, &ad_info)) {
 			seq_printf(seq, "bond %s has no active aggregator\n",
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 0f539de..a79b7c3 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -920,6 +920,38 @@ static ssize_t bonding_store_min_links(struct device *d,
 static DEVICE_ATTR(min_links, S_IRUGO | S_IWUSR,
 		   bonding_show_min_links, bonding_store_min_links);

+static ssize_t bonding_show_lacp_port_id(struct device *d,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	struct bonding *bond = to_bond(d);
+
+	return sprintf(buf, "%d\n", bond->params.lacp_port_id);
+}
+
+static ssize_t bonding_store_lacp_port_id(struct device *d,
+				       struct device_attribute *attr,
+				       const char *buf, size_t count)
+{
+	struct bonding *bond = to_bond(d);
+	int ret;
+	unsigned int new_value;
+
+	ret = kstrtouint(buf, 0, &new_value);
+	if ((ret < 0) || (new_value < 1) || (new_value > 65000)) {
+		pr_err("%s: Ignoring invalid 802.3ad port id value %s.\n",
+		       bond->dev->name, buf);
+		return -EINVAL;
+	}
+
+	pr_info("%s: Setting 802.3ad port id value to %u\n",
+		bond->dev->name, new_value);
+	bond->params.lacp_port_id = new_value;
+	return count;
+}
+static DEVICE_ATTR(lacp_port_id, S_IRUGO | S_IWUSR,
+		   bonding_show_lacp_port_id, bonding_store_lacp_port_id);
+
 static ssize_t bonding_show_ad_select(struct device *d,
 				      struct device_attribute *attr,
 				      char *buf)
@@ -1705,6 +1737,7 @@ static struct attribute *per_bond_attrs[] = {
 	&dev_attr_all_slaves_active.attr,
 	&dev_attr_resend_igmp.attr,
 	&dev_attr_min_links.attr,
+	&dev_attr_lacp_port_id.attr,
 	NULL,
 };

diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 4bf52d5..8a078d6 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -176,6 +176,7 @@ struct bond_params {
 	int tx_queues;
 	int all_slaves_active;
 	int resend_igmp;
+	int lacp_port_id;
 };

 struct bond_parm_tbl {
-- 
1.8.3.1