pkt_action: add new action skbedit

This new action will have the ability to change the priority and/or
queue_mapping fields on an sk_buff.

Signed-off-by: Alexander Duyck <[e-mail]>
Signed-off-by: Jeff Kirsher <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/networking/multiqueue.txt

···
 Traffic will begin flowing through each queue if your base device has either
 the default simple_tx_hash or a custom netdev->select_queue() defined.
 
-The behavior of tc filters remains the same.
+The behavior of tc filters remains the same.  However a new tc action,
+skbedit, has been added.  Assuming you wanted to route all traffic to a
+specific host, for example 192.168.0.3, though a specific queue you could use
+this action and establish a filter such as:
+
+tc filter add dev eth0 parent 1: protocol ip prio 1 u32 \
+	match ip dst 192.168.0.3 \
+	action skbedit queue_mapping 3
 
 Author: Alexander Duyck <[e-mail]>
 Original Author: Peter P. Waskiewicz Jr. <[e-mail]>

include/linux/tc_act/Kbuild

···
 header-y += tc_mirred.h
 header-y += tc_pedit.h
 header-y += tc_nat.h
+header-y += tc_skbedit.h

include/linux/tc_act/tc_skbedit.h

···
+/*
+ * Copyright (c) 2008, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Author: Alexander Duyck <[e-mail]>
+ */
+
+#ifndef __LINUX_TC_SKBEDIT_H
+#define __LINUX_TC_SKBEDIT_H
+
+#include <linux/pkt_cls.h>
+
+#define TCA_ACT_SKBEDIT 11
+
+#define SKBEDIT_F_PRIORITY		0x1
+#define SKBEDIT_F_QUEUE_MAPPING		0x2
+
+struct tc_skbedit {
+	tc_gen;
+};
+
+enum {
+	TCA_SKBEDIT_UNSPEC,
+	TCA_SKBEDIT_TM,
+	TCA_SKBEDIT_PARMS,
+	TCA_SKBEDIT_PRIORITY,
+	TCA_SKBEDIT_QUEUE_MAPPING,
+	__TCA_SKBEDIT_MAX
+};
+#define TCA_SKBEDIT_MAX (__TCA_SKBEDIT_MAX - 1)
+
+#endif

include/net/tc_act/tc_skbedit.h

···
+/*
+ * Copyright (c) 2008, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Author: Alexander Duyck <[e-mail]>
+ */
+
+#ifndef __NET_TC_SKBEDIT_H
+#define __NET_TC_SKBEDIT_H
+
+#include <net/act_api.h>
+
+struct tcf_skbedit {
+	struct tcf_common	common;
+	u32			flags;
+	u32     		priority;
+	u16			queue_mapping;
+};
+#define to_skbedit(pc) \
+	container_of(pc, struct tcf_skbedit, common)
+
+#endif /* __NET_TC_SKBEDIT_H */

net/sched/Kconfig

···
 	  To compile this code as a module, choose M here: the
 	  module will be called simple.
 
+config NET_ACT_SKBEDIT
+        tristate "SKB Editing"
+        depends on NET_CLS_ACT
+        ---help---
+	  Say Y here to change skb priority or queue_mapping settings.
+
+	  If unsure, say N.
+
+	  To compile this code as a module, choose M here: the
+	  module will be called skbedit.
+
 config NET_CLS_IND
 	bool "Incoming device classification"
 	depends on NET_CLS_U32 || NET_CLS_FW

net/sched/Makefile

···
 obj-$(CONFIG_NET_ACT_NAT)	+= act_nat.o
 obj-$(CONFIG_NET_ACT_PEDIT)	+= act_pedit.o
 obj-$(CONFIG_NET_ACT_SIMP)	+= act_simple.o
+obj-$(CONFIG_NET_ACT_SKBEDIT)	+= act_skbedit.o
 obj-$(CONFIG_NET_SCH_FIFO)	+= sch_fifo.o
 obj-$(CONFIG_NET_SCH_CBQ)	+= sch_cbq.o
 obj-$(CONFIG_NET_SCH_HTB)	+= sch_htb.o

net/sched/act_skbedit.c

···
+/*
+ * Copyright (c) 2008, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Author: Alexander Duyck <[e-mail]>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+
+#include <linux/tc_act/tc_skbedit.h>
+#include <net/tc_act/tc_skbedit.h>
+
+#define SKBEDIT_TAB_MASK     15
+static struct tcf_common *tcf_skbedit_ht[SKBEDIT_TAB_MASK + 1];
+static u32 skbedit_idx_gen;
+static DEFINE_RWLOCK(skbedit_lock);
+
+static struct tcf_hashinfo skbedit_hash_info = {
+	.htab	=	tcf_skbedit_ht,
+	.hmask	=	SKBEDIT_TAB_MASK,
+	.lock	=	&skbedit_lock,
+};
+
+static int tcf_skbedit(struct sk_buff *skb, struct tc_action *a,
+		       struct tcf_result *res)
+{
+	struct tcf_skbedit *d = a->priv;
+
+	spin_lock(&d->tcf_lock);
+	d->tcf_tm.lastuse = jiffies;
+	d->tcf_bstats.bytes += qdisc_pkt_len(skb);
+	d->tcf_bstats.packets++;
+
+	if (d->flags & SKBEDIT_F_PRIORITY)
+		skb->priority = d->priority;
+	if (d->flags & SKBEDIT_F_QUEUE_MAPPING &&
+	    skb->dev->real_num_tx_queues > d->queue_mapping)
+		skb_set_queue_mapping(skb, d->queue_mapping);
+
+	spin_unlock(&d->tcf_lock);
+	return d->tcf_action;
+}
+
+static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = {
+	[TCA_SKBEDIT_PARMS]		= { .len = sizeof(struct tc_skbedit) },
+	[TCA_SKBEDIT_PRIORITY]		= { .len = sizeof(u32) },
+	[TCA_SKBEDIT_QUEUE_MAPPING]	= { .len = sizeof(u16) },
+};
+
+static int tcf_skbedit_init(struct nlattr *nla, struct nlattr *est,
+			 struct tc_action *a, int ovr, int bind)
+{
+	struct nlattr *tb[TCA_SKBEDIT_MAX + 1];
+	struct tc_skbedit *parm;
+	struct tcf_skbedit *d;
+	struct tcf_common *pc;
+	u32 flags = 0, *priority = NULL;
+	u16 *queue_mapping = NULL;
+	int ret = 0, err;
+
+	if (nla == NULL)
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, TCA_SKBEDIT_MAX, nla, skbedit_policy);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_SKBEDIT_PARMS] == NULL)
+		return -EINVAL;
+
+	if (tb[TCA_SKBEDIT_PRIORITY] != NULL) {
+		flags |= SKBEDIT_F_PRIORITY;
+		priority = nla_data(tb[TCA_SKBEDIT_PRIORITY]);
+	}
+
+	if (tb[TCA_SKBEDIT_QUEUE_MAPPING] != NULL) {
+		flags |= SKBEDIT_F_QUEUE_MAPPING;
+		queue_mapping = nla_data(tb[TCA_SKBEDIT_QUEUE_MAPPING]);
+	}
+	if (!flags)
+		return -EINVAL;
+
+	parm = nla_data(tb[TCA_SKBEDIT_PARMS]);
+
+	pc = tcf_hash_check(parm->index, a, bind, &skbedit_hash_info);
+	if (!pc) {
+		pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
+				     &skbedit_idx_gen, &skbedit_hash_info);
+		if (unlikely(!pc))
+			return -ENOMEM;
+
+		d = to_skbedit(pc);
+		ret = ACT_P_CREATED;
+	} else {
+		d = to_skbedit(pc);
+		if (!ovr) {
+			tcf_hash_release(pc, bind, &skbedit_hash_info);
+			return -EEXIST;
+		}
+	}
+
+	spin_lock_bh(&d->tcf_lock);
+
+	d->flags = flags;
+	if (flags & SKBEDIT_F_PRIORITY)
+		d->priority = *priority;
+	if (flags & SKBEDIT_F_QUEUE_MAPPING)
+		d->queue_mapping = *queue_mapping;
+	d->tcf_action = parm->action;
+
+	spin_unlock_bh(&d->tcf_lock);
+
+	if (ret == ACT_P_CREATED)
+		tcf_hash_insert(pc, &skbedit_hash_info);
+	return ret;
+}
+
+static inline int tcf_skbedit_cleanup(struct tc_action *a, int bind)
+{
+	struct tcf_skbedit *d = a->priv;
+
+	if (d)
+		return tcf_hash_release(&d->common, bind, &skbedit_hash_info);
+	return 0;
+}
+
+static inline int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
+				int bind, int ref)
+{
+	unsigned char *b = skb_tail_pointer(skb);
+	struct tcf_skbedit *d = a->priv;
+	struct tc_skbedit opt;
+	struct tcf_t t;
+
+	opt.index = d->tcf_index;
+	opt.refcnt = d->tcf_refcnt - ref;
+	opt.bindcnt = d->tcf_bindcnt - bind;
+	opt.action = d->tcf_action;
+	NLA_PUT(skb, TCA_SKBEDIT_PARMS, sizeof(opt), &opt);
+	if (d->flags & SKBEDIT_F_PRIORITY)
+		NLA_PUT(skb, TCA_SKBEDIT_PRIORITY, sizeof(d->priority),
+			&d->priority);
+	if (d->flags & SKBEDIT_F_QUEUE_MAPPING)
+		NLA_PUT(skb, TCA_SKBEDIT_QUEUE_MAPPING,
+			sizeof(d->queue_mapping), &d->queue_mapping);
+	t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
+	t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
+	t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
+	NLA_PUT(skb, TCA_SKBEDIT_TM, sizeof(t), &t);
+	return skb->len;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static struct tc_action_ops act_skbedit_ops = {
+	.kind		=	"skbedit",
+	.hinfo		=	&skbedit_hash_info,
+	.type		=	TCA_ACT_SKBEDIT,
+	.capab		=	TCA_CAP_NONE,
+	.owner		=	THIS_MODULE,
+	.act		=	tcf_skbedit,
+	.dump		=	tcf_skbedit_dump,
+	.cleanup	=	tcf_skbedit_cleanup,
+	.init		=	tcf_skbedit_init,
+	.walk		=	tcf_generic_walker,
+};
+
+MODULE_AUTHOR("Alexander Duyck, <[e-mail]>");
+MODULE_DESCRIPTION("SKB Editing");
+MODULE_LICENSE("GPL");
+
+static int __init skbedit_init_module(void)
+{
+	return tcf_register_action(&act_skbedit_ops);
+}
+
+static void __exit skbedit_cleanup_module(void)
+{
+	tcf_unregister_action(&act_skbedit_ops);
+}
+
+module_init(skbedit_init_module);
+module_exit(skbedit_cleanup_module);