team: add loadbalance mode

This patch introduces new team mode. It's TX port is selected by
user-set BPF hash function.
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/team/Kconfig

@@ -40,4 +40,15 @@ config NET_TEAM_MODE_ACTIVEBACKUP
 	  To compile this team mode as a module, choose M here: the module
 	  will be called team_mode_activebackup.
 
+config NET_TEAM_MODE_LOADBALANCE
+	tristate "Load-balance mode support"
+	depends on NET_TEAM
+	---help---
+	  This mode provides load balancing functionality. Tx port selection
+	  is done using BPF function set up from userspace (bpf_hash_func
+	  option)
+
+	  To compile this team mode as a module, choose M here: the module
+	  will be called team_mode_loadbalance.
+
 endif # NET_TEAM

drivers/net/team/Makefile

@@ -5,3 +5,4 @@
 obj-$(CONFIG_NET_TEAM) += team.o
 obj-$(CONFIG_NET_TEAM_MODE_ROUNDROBIN) += team_mode_roundrobin.o
 obj-$(CONFIG_NET_TEAM_MODE_ACTIVEBACKUP) += team_mode_activebackup.o
+obj-$(CONFIG_NET_TEAM_MODE_LOADBALANCE) += team_mode_loadbalance.o

drivers/net/team/team_mode_loadbalance.c

+/*
+ * drivers/net/team/team_mode_loadbalance.c - Load-balancing mode for team
+ * Copyright (c) 2012 Jiri Pirko <jpirko@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/filter.h>
+#include <linux/if_team.h>
+
+struct lb_priv {
+	struct sk_filter __rcu *fp;
+	struct sock_fprog *orig_fprog;
+};
+
+static struct lb_priv *lb_priv(struct team *team)
+{
+	return (struct lb_priv *) &team->mode_priv;
+}
+
+static bool lb_transmit(struct team *team, struct sk_buff *skb)
+{
+	struct sk_filter *fp;
+	struct team_port *port;
+	unsigned int hash;
+	int port_index;
+
+	fp = rcu_dereference(lb_priv(team)->fp);
+	if (unlikely(!fp))
+		goto drop;
+	hash = SK_RUN_FILTER(fp, skb);
+	port_index = hash % team->port_count;
+	port = team_get_port_by_index_rcu(team, port_index);
+	if (unlikely(!port))
+		goto drop;
+	skb->dev = port->dev;
+	if (dev_queue_xmit(skb))
+		return false;
+	return true;
+
+drop:
+	dev_kfree_skb_any(skb);
+	return false;
+}
+
+static int lb_bpf_func_get(struct team *team, void *arg)
+{
+	struct team_option_binary *tbinary = team_optarg_tbinary(arg);
+
+	memset(tbinary, 0, sizeof(*tbinary));
+	if (!lb_priv(team)->orig_fprog)
+		return 0;
+
+	tbinary->data_len = lb_priv(team)->orig_fprog->len *
+			    sizeof(struct sock_filter);
+	tbinary->data = lb_priv(team)->orig_fprog->filter;
+	return 0;
+}
+
+static int __fprog_create(struct sock_fprog **pfprog, u32 data_len,
+			  void *data)
+{
+	struct sock_fprog *fprog;
+	struct sock_filter *filter = (struct sock_filter *) data;
+
+	if (data_len % sizeof(struct sock_filter))
+		return -EINVAL;
+	fprog = kmalloc(sizeof(struct sock_fprog), GFP_KERNEL);
+	if (!fprog)
+		return -ENOMEM;
+	fprog->filter = kmemdup(filter, data_len, GFP_KERNEL);
+	if (!fprog->filter) {
+		kfree(fprog);
+		return -ENOMEM;
+	}
+	fprog->len = data_len / sizeof(struct sock_filter);
+	*pfprog = fprog;
+	return 0;
+}
+
+static void __fprog_destroy(struct sock_fprog *fprog)
+{
+	kfree(fprog->filter);
+	kfree(fprog);
+}
+
+static int lb_bpf_func_set(struct team *team, void *arg)
+{
+	struct team_option_binary *tbinary = team_optarg_tbinary(arg);
+	struct sk_filter *fp = NULL;
+	struct sock_fprog *fprog = NULL;
+	int err;
+
+	if (tbinary->data_len) {
+		err = __fprog_create(&fprog, tbinary->data_len,
+				     tbinary->data);
+		if (err)
+			return err;
+		err = sk_unattached_filter_create(&fp, fprog);
+		if (err) {
+			__fprog_destroy(fprog);
+			return err;
+		}
+	}
+
+	if (lb_priv(team)->orig_fprog) {
+		/* Clear old filter data */
+		__fprog_destroy(lb_priv(team)->orig_fprog);
+		sk_unattached_filter_destroy(lb_priv(team)->fp);
+	}
+
+	rcu_assign_pointer(lb_priv(team)->fp, fp);
+	lb_priv(team)->orig_fprog = fprog;
+	return 0;
+}
+
+static const struct team_option lb_options[] = {
+	{
+		.name = "bpf_hash_func",
+		.type = TEAM_OPTION_TYPE_BINARY,
+		.getter = lb_bpf_func_get,
+		.setter = lb_bpf_func_set,
+	},
+};
+
+int lb_init(struct team *team)
+{
+	return team_options_register(team, lb_options,
+				     ARRAY_SIZE(lb_options));
+}
+
+void lb_exit(struct team *team)
+{
+	team_options_unregister(team, lb_options,
+				ARRAY_SIZE(lb_options));
+}
+
+static int lb_port_enter(struct team *team, struct team_port *port)
+{
+	return team_port_set_team_mac(port);
+}
+
+static void lb_port_change_mac(struct team *team, struct team_port *port)
+{
+	team_port_set_team_mac(port);
+}
+
+static const struct team_mode_ops lb_mode_ops = {
+	.init			= lb_init,
+	.exit			= lb_exit,
+	.transmit		= lb_transmit,
+	.port_enter		= lb_port_enter,
+	.port_change_mac	= lb_port_change_mac,
+};
+
+static struct team_mode lb_mode = {
+	.kind		= "loadbalance",
+	.owner		= THIS_MODULE,
+	.priv_size	= sizeof(struct lb_priv),
+	.ops		= &lb_mode_ops,
+};
+
+static int __init lb_init_module(void)
+{
+	return team_mode_register(&lb_mode);
+}
+
+static void __exit lb_cleanup_module(void)
+{
+	team_mode_unregister(&lb_mode);
+}
+
+module_init(lb_init_module);
+module_exit(lb_cleanup_module);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Jiri Pirko <jpirko@redhat.com>");
+MODULE_DESCRIPTION("Load-balancing mode for team");
+MODULE_ALIAS("team-mode-loadbalance");