datapath.c 51.7 KB
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/*
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 * Copyright (c) 2007-2014 Nicira, Inc.
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 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/jhash.h>
#include <linux/delay.h>
#include <linux/time.h>
#include <linux/etherdevice.h>
#include <linux/genetlink.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/ethtool.h>
#include <linux/wait.h>
#include <asm/div64.h>
#include <linux/highmem.h>
#include <linux/netfilter_bridge.h>
#include <linux/netfilter_ipv4.h>
#include <linux/inetdevice.h>
#include <linux/list.h>
#include <linux/openvswitch.h>
#include <linux/rculist.h>
#include <linux/dmi.h>
#include <net/genetlink.h>
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#include <net/net_namespace.h>
#include <net/netns/generic.h>
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#include "datapath.h"
#include "flow.h"
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#include "flow_table.h"
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#include "flow_netlink.h"
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#include "vport-internal_dev.h"
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#include "vport-netdev.h"
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int ovs_net_id __read_mostly;
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EXPORT_SYMBOL_GPL(ovs_net_id);
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static struct genl_family dp_packet_genl_family;
static struct genl_family dp_flow_genl_family;
static struct genl_family dp_datapath_genl_family;

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static const struct genl_multicast_group ovs_dp_flow_multicast_group = {
	.name = OVS_FLOW_MCGROUP,
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};

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static const struct genl_multicast_group ovs_dp_datapath_multicast_group = {
	.name = OVS_DATAPATH_MCGROUP,
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};

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static const struct genl_multicast_group ovs_dp_vport_multicast_group = {
	.name = OVS_VPORT_MCGROUP,
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};

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/* Check if need to build a reply message.
 * OVS userspace sets the NLM_F_ECHO flag if it needs the reply. */
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static bool ovs_must_notify(struct genl_family *family, struct genl_info *info,
			    unsigned int group)
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{
	return info->nlhdr->nlmsg_flags & NLM_F_ECHO ||
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	       genl_has_listeners(family, genl_info_net(info)->genl_sock,
				  group);
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}

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static void ovs_notify(struct genl_family *family,
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		       struct sk_buff *skb, struct genl_info *info)
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{
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	genl_notify(family, skb, genl_info_net(info), info->snd_portid,
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		    0, info->nlhdr, GFP_KERNEL);
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}

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/**
 * DOC: Locking:
 *
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 * All writes e.g. Writes to device state (add/remove datapath, port, set
 * operations on vports, etc.), Writes to other state (flow table
 * modifications, set miscellaneous datapath parameters, etc.) are protected
 * by ovs_lock.
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 *
 * Reads are protected by RCU.
 *
 * There are a few special cases (mostly stats) that have their own
 * synchronization but they nest under all of above and don't interact with
 * each other.
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 *
 * The RTNL lock nests inside ovs_mutex.
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 */

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static DEFINE_MUTEX(ovs_mutex);

void ovs_lock(void)
{
	mutex_lock(&ovs_mutex);
}

void ovs_unlock(void)
{
	mutex_unlock(&ovs_mutex);
}

#ifdef CONFIG_LOCKDEP
int lockdep_ovsl_is_held(void)
{
	if (debug_locks)
		return lockdep_is_held(&ovs_mutex);
	else
		return 1;
}
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EXPORT_SYMBOL_GPL(lockdep_ovsl_is_held);
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#endif

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static struct vport *new_vport(const struct vport_parms *);
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static int queue_gso_packets(struct datapath *dp, struct sk_buff *,
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			     const struct dp_upcall_info *);
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static int queue_userspace_packet(struct datapath *dp, struct sk_buff *,
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				  const struct dp_upcall_info *);

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/* Must be called with rcu_read_lock. */
static struct datapath *get_dp_rcu(struct net *net, int dp_ifindex)
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{
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	struct net_device *dev = dev_get_by_index_rcu(net, dp_ifindex);
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	if (dev) {
		struct vport *vport = ovs_internal_dev_get_vport(dev);
		if (vport)
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			return vport->dp;
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	}
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	return NULL;
}

/* The caller must hold either ovs_mutex or rcu_read_lock to keep the
 * returned dp pointer valid.
 */
static inline struct datapath *get_dp(struct net *net, int dp_ifindex)
{
	struct datapath *dp;

	WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_ovsl_is_held());
	rcu_read_lock();
	dp = get_dp_rcu(net, dp_ifindex);
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	rcu_read_unlock();

	return dp;
}

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/* Must be called with rcu_read_lock or ovs_mutex. */
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const char *ovs_dp_name(const struct datapath *dp)
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{
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	struct vport *vport = ovs_vport_ovsl_rcu(dp, OVSP_LOCAL);
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	return vport->ops->get_name(vport);
}

static int get_dpifindex(struct datapath *dp)
{
	struct vport *local;
	int ifindex;

	rcu_read_lock();

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	local = ovs_vport_rcu(dp, OVSP_LOCAL);
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	if (local)
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		ifindex = netdev_vport_priv(local)->dev->ifindex;
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	else
		ifindex = 0;

	rcu_read_unlock();

	return ifindex;
}

static void destroy_dp_rcu(struct rcu_head *rcu)
{
	struct datapath *dp = container_of(rcu, struct datapath, rcu);

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	ovs_flow_tbl_destroy(&dp->table);
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	free_percpu(dp->stats_percpu);
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	release_net(ovs_dp_get_net(dp));
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	kfree(dp->ports);
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	kfree(dp);
}

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static struct hlist_head *vport_hash_bucket(const struct datapath *dp,
					    u16 port_no)
{
	return &dp->ports[port_no & (DP_VPORT_HASH_BUCKETS - 1)];
}

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/* Called with ovs_mutex or RCU read lock. */
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struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no)
{
	struct vport *vport;
	struct hlist_head *head;

	head = vport_hash_bucket(dp, port_no);
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	hlist_for_each_entry_rcu(vport, head, dp_hash_node) {
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		if (vport->port_no == port_no)
			return vport;
	}
	return NULL;
}

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/* Called with ovs_mutex. */
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static struct vport *new_vport(const struct vport_parms *parms)
{
	struct vport *vport;

	vport = ovs_vport_add(parms);
	if (!IS_ERR(vport)) {
		struct datapath *dp = parms->dp;
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		struct hlist_head *head = vport_hash_bucket(dp, vport->port_no);
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		hlist_add_head_rcu(&vport->dp_hash_node, head);
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	}
	return vport;
}

void ovs_dp_detach_port(struct vport *p)
{
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	ASSERT_OVSL();
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	/* First drop references to device. */
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	hlist_del_rcu(&p->dp_hash_node);
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	/* Then destroy it. */
	ovs_vport_del(p);
}

/* Must be called with rcu_read_lock. */
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void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key)
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{
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	const struct vport *p = OVS_CB(skb)->input_vport;
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	struct datapath *dp = p->dp;
	struct sw_flow *flow;
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	struct sw_flow_actions *sf_acts;
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	struct dp_stats_percpu *stats;
	u64 *stats_counter;
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	u32 n_mask_hit;
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	stats = this_cpu_ptr(dp->stats_percpu);
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	/* Look up flow. */
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	flow = ovs_flow_tbl_lookup_stats(&dp->table, key, &n_mask_hit);
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	if (unlikely(!flow)) {
		struct dp_upcall_info upcall;
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		int error;
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		upcall.cmd = OVS_PACKET_CMD_MISS;
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		upcall.key = key;
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		upcall.userdata = NULL;
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		upcall.portid = ovs_vport_find_upcall_portid(p, skb);
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		error = ovs_dp_upcall(dp, skb, &upcall);
		if (unlikely(error))
			kfree_skb(skb);
		else
			consume_skb(skb);
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		stats_counter = &stats->n_missed;
		goto out;
	}

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	ovs_flow_stats_update(flow, key->tp.flags, skb);
	sf_acts = rcu_dereference(flow->sf_acts);
	ovs_execute_actions(dp, skb, sf_acts, key);
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	stats_counter = &stats->n_hit;
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out:
	/* Update datapath statistics. */
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	u64_stats_update_begin(&stats->syncp);
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	(*stats_counter)++;
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	stats->n_mask_hit += n_mask_hit;
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	u64_stats_update_end(&stats->syncp);
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}

int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
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		  const struct dp_upcall_info *upcall_info)
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{
	struct dp_stats_percpu *stats;
	int err;

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	if (upcall_info->portid == 0) {
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		err = -ENOTCONN;
		goto err;
	}

	if (!skb_is_gso(skb))
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		err = queue_userspace_packet(dp, skb, upcall_info);
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	else
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		err = queue_gso_packets(dp, skb, upcall_info);
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	if (err)
		goto err;

	return 0;

err:
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	stats = this_cpu_ptr(dp->stats_percpu);
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	u64_stats_update_begin(&stats->syncp);
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	stats->n_lost++;
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	u64_stats_update_end(&stats->syncp);
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	return err;
}

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static int queue_gso_packets(struct datapath *dp, struct sk_buff *skb,
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			     const struct dp_upcall_info *upcall_info)
{
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	unsigned short gso_type = skb_shinfo(skb)->gso_type;
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	struct dp_upcall_info later_info;
	struct sw_flow_key later_key;
	struct sk_buff *segs, *nskb;
	int err;

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	segs = __skb_gso_segment(skb, NETIF_F_SG, false);
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	if (IS_ERR(segs))
		return PTR_ERR(segs);
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	if (segs == NULL)
		return -EINVAL;
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	/* Queue all of the segments. */
	skb = segs;
	do {
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		err = queue_userspace_packet(dp, skb, upcall_info);
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		if (err)
			break;

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		if (skb == segs && gso_type & SKB_GSO_UDP) {
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			/* The initial flow key extracted by ovs_flow_extract()
			 * in this case is for a first fragment, so we need to
			 * properly mark later fragments.
			 */
			later_key = *upcall_info->key;
			later_key.ip.frag = OVS_FRAG_TYPE_LATER;

			later_info = *upcall_info;
			later_info.key = &later_key;
			upcall_info = &later_info;
		}
	} while ((skb = skb->next));

	/* Free all of the segments. */
	skb = segs;
	do {
		nskb = skb->next;
		if (err)
			kfree_skb(skb);
		else
			consume_skb(skb);
	} while ((skb = nskb));
	return err;
}

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static size_t upcall_msg_size(const struct nlattr *userdata,
			      unsigned int hdrlen)
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{
	size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
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		+ nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */
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		+ nla_total_size(ovs_key_attr_size()); /* OVS_PACKET_ATTR_KEY */
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	/* OVS_PACKET_ATTR_USERDATA */
	if (userdata)
		size += NLA_ALIGN(userdata->nla_len);

	return size;
}

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static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
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				  const struct dp_upcall_info *upcall_info)
{
	struct ovs_header *upcall;
	struct sk_buff *nskb = NULL;
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	struct sk_buff *user_skb = NULL; /* to be queued to userspace */
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	struct nlattr *nla;
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	struct genl_info info = {
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		.dst_sk = ovs_dp_get_net(dp)->genl_sock,
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		.snd_portid = upcall_info->portid,
	};
	size_t len;
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	unsigned int hlen;
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	int err, dp_ifindex;

	dp_ifindex = get_dpifindex(dp);
	if (!dp_ifindex)
		return -ENODEV;
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	if (vlan_tx_tag_present(skb)) {
		nskb = skb_clone(skb, GFP_ATOMIC);
		if (!nskb)
			return -ENOMEM;

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		nskb = __vlan_put_tag(nskb, nskb->vlan_proto, vlan_tx_tag_get(nskb));
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		if (!nskb)
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			return -ENOMEM;

		nskb->vlan_tci = 0;
		skb = nskb;
	}

	if (nla_attr_size(skb->len) > USHRT_MAX) {
		err = -EFBIG;
		goto out;
	}

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	/* Complete checksum if needed */
	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	    (err = skb_checksum_help(skb)))
		goto out;

	/* Older versions of OVS user space enforce alignment of the last
	 * Netlink attribute to NLA_ALIGNTO which would require extensive
	 * padding logic. Only perform zerocopy if padding is not required.
	 */
	if (dp->user_features & OVS_DP_F_UNALIGNED)
		hlen = skb_zerocopy_headlen(skb);
	else
		hlen = skb->len;

	len = upcall_msg_size(upcall_info->userdata, hlen);
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	user_skb = genlmsg_new_unicast(len, &info, GFP_ATOMIC);
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	if (!user_skb) {
		err = -ENOMEM;
		goto out;
	}

	upcall = genlmsg_put(user_skb, 0, 0, &dp_packet_genl_family,
			     0, upcall_info->cmd);
	upcall->dp_ifindex = dp_ifindex;

	nla = nla_nest_start(user_skb, OVS_PACKET_ATTR_KEY);
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	err = ovs_nla_put_flow(upcall_info->key, upcall_info->key, user_skb);
	BUG_ON(err);
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	nla_nest_end(user_skb, nla);

	if (upcall_info->userdata)
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		__nla_put(user_skb, OVS_PACKET_ATTR_USERDATA,
			  nla_len(upcall_info->userdata),
			  nla_data(upcall_info->userdata));
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	/* Only reserve room for attribute header, packet data is added
	 * in skb_zerocopy() */
	if (!(nla = nla_reserve(user_skb, OVS_PACKET_ATTR_PACKET, 0))) {
		err = -ENOBUFS;
		goto out;
	}
	nla->nla_len = nla_attr_size(skb->len);
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	err = skb_zerocopy(user_skb, skb, skb->len, hlen);
	if (err)
		goto out;
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	/* Pad OVS_PACKET_ATTR_PACKET if linear copy was performed */
	if (!(dp->user_features & OVS_DP_F_UNALIGNED)) {
		size_t plen = NLA_ALIGN(user_skb->len) - user_skb->len;

		if (plen > 0)
			memset(skb_put(user_skb, plen), 0, plen);
	}

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	((struct nlmsghdr *) user_skb->data)->nlmsg_len = user_skb->len;
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	err = genlmsg_unicast(ovs_dp_get_net(dp), user_skb, upcall_info->portid);
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	user_skb = NULL;
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out:
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	if (err)
		skb_tx_error(skb);
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	kfree_skb(user_skb);
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	kfree_skb(nskb);
	return err;
}

static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
{
	struct ovs_header *ovs_header = info->userhdr;
	struct nlattr **a = info->attrs;
	struct sw_flow_actions *acts;
	struct sk_buff *packet;
	struct sw_flow *flow;
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	struct sw_flow_actions *sf_acts;
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	struct datapath *dp;
	struct ethhdr *eth;
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	struct vport *input_vport;
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	int len;
	int err;

	err = -EINVAL;
	if (!a[OVS_PACKET_ATTR_PACKET] || !a[OVS_PACKET_ATTR_KEY] ||
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	    !a[OVS_PACKET_ATTR_ACTIONS])
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		goto err;

	len = nla_len(a[OVS_PACKET_ATTR_PACKET]);
	packet = __dev_alloc_skb(NET_IP_ALIGN + len, GFP_KERNEL);
	err = -ENOMEM;
	if (!packet)
		goto err;
	skb_reserve(packet, NET_IP_ALIGN);

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	nla_memcpy(__skb_put(packet, len), a[OVS_PACKET_ATTR_PACKET], len);
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	skb_reset_mac_header(packet);
	eth = eth_hdr(packet);

	/* Normally, setting the skb 'protocol' field would be handled by a
	 * call to eth_type_trans(), but it assumes there's a sending
	 * device, which we may not have. */
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	if (ntohs(eth->h_proto) >= ETH_P_802_3_MIN)
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		packet->protocol = eth->h_proto;
	else
		packet->protocol = htons(ETH_P_802_2);

	/* Build an sw_flow for sending this packet. */
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	flow = ovs_flow_alloc();
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	err = PTR_ERR(flow);
	if (IS_ERR(flow))
		goto err_kfree_skb;

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	err = ovs_flow_key_extract_userspace(a[OVS_PACKET_ATTR_KEY], packet,
					     &flow->key);
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	if (err)
		goto err_flow_free;

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	err = ovs_nla_copy_actions(a[OVS_PACKET_ATTR_ACTIONS],
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				   &flow->key, &acts);
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	if (err)
		goto err_flow_free;
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	rcu_assign_pointer(flow->sf_acts, acts);
	OVS_CB(packet)->egress_tun_info = NULL;
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	packet->priority = flow->key.phy.priority;
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	packet->mark = flow->key.phy.skb_mark;
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	rcu_read_lock();
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	dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex);
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	err = -ENODEV;
	if (!dp)
		goto err_unlock;

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	input_vport = ovs_vport_rcu(dp, flow->key.phy.in_port);
	if (!input_vport)
		input_vport = ovs_vport_rcu(dp, OVSP_LOCAL);

	if (!input_vport)
		goto err_unlock;

	OVS_CB(packet)->input_vport = input_vport;
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	sf_acts = rcu_dereference(flow->sf_acts);
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	local_bh_disable();
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	err = ovs_execute_actions(dp, packet, sf_acts, &flow->key);
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	local_bh_enable();
	rcu_read_unlock();

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	ovs_flow_free(flow, false);
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	return err;

err_unlock:
	rcu_read_unlock();
err_flow_free:
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	ovs_flow_free(flow, false);
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err_kfree_skb:
	kfree_skb(packet);
err:
	return err;
}

static const struct nla_policy packet_policy[OVS_PACKET_ATTR_MAX + 1] = {
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	[OVS_PACKET_ATTR_PACKET] = { .len = ETH_HLEN },
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	[OVS_PACKET_ATTR_KEY] = { .type = NLA_NESTED },
	[OVS_PACKET_ATTR_ACTIONS] = { .type = NLA_NESTED },
};

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static const struct genl_ops dp_packet_genl_ops[] = {
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	{ .cmd = OVS_PACKET_CMD_EXECUTE,
	  .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
	  .policy = packet_policy,
	  .doit = ovs_packet_cmd_execute
	}
};

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static struct genl_family dp_packet_genl_family = {
	.id = GENL_ID_GENERATE,
	.hdrsize = sizeof(struct ovs_header),
	.name = OVS_PACKET_FAMILY,
	.version = OVS_PACKET_VERSION,
	.maxattr = OVS_PACKET_ATTR_MAX,
	.netnsok = true,
	.parallel_ops = true,
	.ops = dp_packet_genl_ops,
	.n_ops = ARRAY_SIZE(dp_packet_genl_ops),
};

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static void get_dp_stats(struct datapath *dp, struct ovs_dp_stats *stats,
			 struct ovs_dp_megaflow_stats *mega_stats)
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{
	int i;

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	memset(mega_stats, 0, sizeof(*mega_stats));

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	stats->n_flows = ovs_flow_tbl_count(&dp->table);
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	mega_stats->n_masks = ovs_flow_tbl_num_masks(&dp->table);
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	stats->n_hit = stats->n_missed = stats->n_lost = 0;
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	for_each_possible_cpu(i) {
		const struct dp_stats_percpu *percpu_stats;
		struct dp_stats_percpu local_stats;
		unsigned int start;

		percpu_stats = per_cpu_ptr(dp->stats_percpu, i);

		do {
636
			start = u64_stats_fetch_begin_irq(&percpu_stats->syncp);
637
			local_stats = *percpu_stats;
638
		} while (u64_stats_fetch_retry_irq(&percpu_stats->syncp, start));
639 640 641 642

		stats->n_hit += local_stats.n_hit;
		stats->n_missed += local_stats.n_missed;
		stats->n_lost += local_stats.n_lost;
643
		mega_stats->n_mask_hit += local_stats.n_mask_hit;
644 645 646
	}
}

647 648 649
static size_t ovs_flow_cmd_msg_size(const struct sw_flow_actions *acts)
{
	return NLMSG_ALIGN(sizeof(struct ovs_header))
650 651
		+ nla_total_size(ovs_key_attr_size()) /* OVS_FLOW_ATTR_KEY */
		+ nla_total_size(ovs_key_attr_size()) /* OVS_FLOW_ATTR_MASK */
652 653 654 655 656 657
		+ nla_total_size(sizeof(struct ovs_flow_stats)) /* OVS_FLOW_ATTR_STATS */
		+ nla_total_size(1) /* OVS_FLOW_ATTR_TCP_FLAGS */
		+ nla_total_size(8) /* OVS_FLOW_ATTR_USED */
		+ nla_total_size(acts->actions_len); /* OVS_FLOW_ATTR_ACTIONS */
}

658
/* Called with ovs_mutex or RCU read lock. */
659 660
static int ovs_flow_cmd_fill_match(const struct sw_flow *flow,
				   struct sk_buff *skb)
661 662 663 664
{
	struct nlattr *nla;
	int err;

665
	/* Fill flow key. */
666 667
	nla = nla_nest_start(skb, OVS_FLOW_ATTR_KEY);
	if (!nla)
668
		return -EMSGSIZE;
669

670
	err = ovs_nla_put_flow(&flow->unmasked_key, &flow->unmasked_key, skb);
671
	if (err)
672 673
		return err;

674 675
	nla_nest_end(skb, nla);

676
	/* Fill flow mask. */
677 678
	nla = nla_nest_start(skb, OVS_FLOW_ATTR_MASK);
	if (!nla)
679
		return -EMSGSIZE;
680

681
	err = ovs_nla_put_flow(&flow->key, &flow->mask->key, skb);
682
	if (err)
683
		return err;
684

685
	nla_nest_end(skb, nla);
686 687 688 689 690 691 692 693 694 695
	return 0;
}

/* Called with ovs_mutex or RCU read lock. */
static int ovs_flow_cmd_fill_stats(const struct sw_flow *flow,
				   struct sk_buff *skb)
{
	struct ovs_flow_stats stats;
	__be16 tcp_flags;
	unsigned long used;
696

697
	ovs_flow_stats_get(flow, &stats, &used, &tcp_flags);
698

699 700
	if (used &&
	    nla_put_u64(skb, OVS_FLOW_ATTR_USED, ovs_flow_used_time(used)))
701
		return -EMSGSIZE;
702

703
	if (stats.n_packets &&
704
	    nla_put(skb, OVS_FLOW_ATTR_STATS, sizeof(struct ovs_flow_stats), &stats))
705
		return -EMSGSIZE;
706

707 708
	if ((u8)ntohs(tcp_flags) &&
	     nla_put_u8(skb, OVS_FLOW_ATTR_TCP_FLAGS, (u8)ntohs(tcp_flags)))
709 710 711 712 713 714 715 716 717 718 719
		return -EMSGSIZE;

	return 0;
}

/* Called with ovs_mutex or RCU read lock. */
static int ovs_flow_cmd_fill_actions(const struct sw_flow *flow,
				     struct sk_buff *skb, int skb_orig_len)
{
	struct nlattr *start;
	int err;
720 721 722 723 724 725 726 727 728 729 730

	/* If OVS_FLOW_ATTR_ACTIONS doesn't fit, skip dumping the actions if
	 * this is the first flow to be dumped into 'skb'.  This is unusual for
	 * Netlink but individual action lists can be longer than
	 * NLMSG_GOODSIZE and thus entirely undumpable if we didn't do this.
	 * The userspace caller can always fetch the actions separately if it
	 * really wants them.  (Most userspace callers in fact don't care.)
	 *
	 * This can only fail for dump operations because the skb is always
	 * properly sized for single flows.
	 */
731 732
	start = nla_nest_start(skb, OVS_FLOW_ATTR_ACTIONS);
	if (start) {
733 734
		const struct sw_flow_actions *sf_acts;

735
		sf_acts = rcu_dereference_ovsl(flow->sf_acts);
736 737
		err = ovs_nla_put_actions(sf_acts->actions,
					  sf_acts->actions_len, skb);
738

739 740 741 742
		if (!err)
			nla_nest_end(skb, start);
		else {
			if (skb_orig_len)
743
				return err;
744 745 746

			nla_nest_cancel(skb, start);
		}
747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780
	} else if (skb_orig_len) {
		return -EMSGSIZE;
	}

	return 0;
}

/* Called with ovs_mutex or RCU read lock. */
static int ovs_flow_cmd_fill_info(const struct sw_flow *flow, int dp_ifindex,
				  struct sk_buff *skb, u32 portid,
				  u32 seq, u32 flags, u8 cmd)
{
	const int skb_orig_len = skb->len;
	struct ovs_header *ovs_header;
	int err;

	ovs_header = genlmsg_put(skb, portid, seq, &dp_flow_genl_family,
				 flags, cmd);
	if (!ovs_header)
		return -EMSGSIZE;

	ovs_header->dp_ifindex = dp_ifindex;

	err = ovs_flow_cmd_fill_match(flow, skb);
	if (err)
		goto error;

	err = ovs_flow_cmd_fill_stats(flow, skb);
	if (err)
		goto error;

	err = ovs_flow_cmd_fill_actions(flow, skb, skb_orig_len);
	if (err)
		goto error;
781 782 783 784 785 786 787 788

	return genlmsg_end(skb, ovs_header);

error:
	genlmsg_cancel(skb, ovs_header);
	return err;
}

789 790
/* May not be called with RCU read lock. */
static struct sk_buff *ovs_flow_cmd_alloc_info(const struct sw_flow_actions *acts,
791 792
					       struct genl_info *info,
					       bool always)
793
{
794
	struct sk_buff *skb;
795

796
	if (!always && !ovs_must_notify(&dp_flow_genl_family, info, 0))
797 798
		return NULL;

799
	skb = genlmsg_new_unicast(ovs_flow_cmd_msg_size(acts), info, GFP_KERNEL);
800 801 802 803
	if (!skb)
		return ERR_PTR(-ENOMEM);

	return skb;
804 805
}

806 807 808 809 810
/* Called with ovs_mutex. */
static struct sk_buff *ovs_flow_cmd_build_info(const struct sw_flow *flow,
					       int dp_ifindex,
					       struct genl_info *info, u8 cmd,
					       bool always)
811 812 813 814
{
	struct sk_buff *skb;
	int retval;

815 816
	skb = ovs_flow_cmd_alloc_info(ovsl_dereference(flow->sf_acts), info,
				      always);
817
	if (IS_ERR_OR_NULL(skb))
818
		return skb;
819

820 821 822
	retval = ovs_flow_cmd_fill_info(flow, dp_ifindex, skb,
					info->snd_portid, info->snd_seq, 0,
					cmd);
823 824 825 826
	BUG_ON(retval < 0);
	return skb;
}

827
static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
828 829 830
{
	struct nlattr **a = info->attrs;
	struct ovs_header *ovs_header = info->userhdr;
831
	struct sw_flow *flow, *new_flow;
832
	struct sw_flow_mask mask;
833 834
	struct sk_buff *reply;
	struct datapath *dp;
835
	struct sw_flow_actions *acts;
836
	struct sw_flow_match match;
837 838
	int error;

839
	/* Must have key and actions. */
840
	error = -EINVAL;
841 842
	if (!a[OVS_FLOW_ATTR_KEY]) {
		OVS_NLERR("Flow key attribute not present in new flow.\n");
843
		goto error;
844 845 846
	}
	if (!a[OVS_FLOW_ATTR_ACTIONS]) {
		OVS_NLERR("Flow actions attribute not present in new flow.\n");
847
		goto error;
848
	}
849

850 851 852 853 854 855 856 857 858 859 860
	/* Most of the time we need to allocate a new flow, do it before
	 * locking.
	 */
	new_flow = ovs_flow_alloc();
	if (IS_ERR(new_flow)) {
		error = PTR_ERR(new_flow);
		goto error;
	}

	/* Extract key. */
	ovs_match_init(&match, &new_flow->unmasked_key, &mask);
861
	error = ovs_nla_get_match(&match,
862
				  a[OVS_FLOW_ATTR_KEY], a[OVS_FLOW_ATTR_MASK]);
863
	if (error)
864
		goto err_kfree_flow;
865

866
	ovs_flow_mask_key(&new_flow->key, &new_flow->unmasked_key, &mask);
867

868 869
	/* Validate actions. */
	error = ovs_nla_copy_actions(a[OVS_FLOW_ATTR_ACTIONS], &new_flow->key,
870
				     &acts);
871 872
	if (error) {
		OVS_NLERR("Flow actions may not be safe on all matching packets.\n");
873
		goto err_kfree_flow;
874 875 876 877 878 879
	}

	reply = ovs_flow_cmd_alloc_info(acts, info, false);
	if (IS_ERR(reply)) {
		error = PTR_ERR(reply);
		goto err_kfree_acts;
880 881
	}

882
	ovs_lock();
883
	dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
884 885
	if (unlikely(!dp)) {
		error = -ENODEV;
886
		goto err_unlock_ovs;
887
	}
888
	/* Check if this is a duplicate flow */
889 890 891
	flow = ovs_flow_tbl_lookup(&dp->table, &new_flow->unmasked_key);
	if (likely(!flow)) {
		rcu_assign_pointer(new_flow->sf_acts, acts);
892 893

		/* Put flow in bucket. */
894 895
		error = ovs_flow_tbl_insert(&dp->table, new_flow, &mask);
		if (unlikely(error)) {
896
			acts = NULL;
897 898 899 900 901 902 903 904 905 906
			goto err_unlock_ovs;
		}

		if (unlikely(reply)) {
			error = ovs_flow_cmd_fill_info(new_flow,
						       ovs_header->dp_ifindex,
						       reply, info->snd_portid,
						       info->snd_seq, 0,
						       OVS_FLOW_CMD_NEW);
			BUG_ON(error < 0);
907
		}
908
		ovs_unlock();
909
	} else {
910 911
		struct sw_flow_actions *old_acts;

912 913 914 915 916 917
		/* Bail out if we're not allowed to modify an existing flow.
		 * We accept NLM_F_CREATE in place of the intended NLM_F_EXCL
		 * because Generic Netlink treats the latter as a dump
		 * request.  We also accept NLM_F_EXCL in case that bug ever
		 * gets fixed.
		 */
918 919 920
		if (unlikely(info->nlhdr->nlmsg_flags & (NLM_F_CREATE
							 | NLM_F_EXCL))) {
			error = -EEXIST;
921
			goto err_unlock_ovs;
922
		}
923
		/* The unmasked key has to be the same for flow updates. */
924
		if (unlikely(!ovs_flow_cmp_unmasked_key(flow, &match))) {
925 926 927 928 929
			flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
			if (!flow) {
				error = -ENOENT;
				goto err_unlock_ovs;
			}
930
		}
931 932 933 934
		/* Update actions. */
		old_acts = ovsl_dereference(flow->sf_acts);
		rcu_assign_pointer(flow->sf_acts, acts);

935 936 937 938 939 940 941 942 943
		if (unlikely(reply)) {
			error = ovs_flow_cmd_fill_info(flow,
						       ovs_header->dp_ifindex,
						       reply, info->snd_portid,
						       info->snd_seq, 0,
						       OVS_FLOW_CMD_NEW);
			BUG_ON(error < 0);
		}
		ovs_unlock();
944

945 946
		ovs_nla_free_flow_actions(old_acts);
		ovs_flow_free(new_flow, false);
947
	}
948 949 950

	if (reply)
		ovs_notify(&dp_flow_genl_family, reply, info);
951 952 953 954
	return 0;

err_unlock_ovs:
	ovs_unlock();
955 956
	kfree_skb(reply);
err_kfree_acts:
957
	kfree(acts);
958 959
err_kfree_flow:
	ovs_flow_free(new_flow, false);
960 961 962
error:
	return error;
}
963

964
/* Factor out action copy to avoid "Wframe-larger-than=1024" warning. */
965 966 967 968 969 970 971 972 973
static struct sw_flow_actions *get_flow_actions(const struct nlattr *a,
						const struct sw_flow_key *key,
						const struct sw_flow_mask *mask)
{
	struct sw_flow_actions *acts;
	struct sw_flow_key masked_key;
	int error;

	ovs_flow_mask_key(&masked_key, key, mask);
974
	error = ovs_nla_copy_actions(a, &masked_key, &acts);
975
	if (error) {
976
		OVS_NLERR("Actions may not be safe on all matching packets.\n");
977 978 979 980 981 982
		return ERR_PTR(error);
	}

	return acts;
}

983 984 985 986
static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
{
	struct nlattr **a = info->attrs;
	struct ovs_header *ovs_header = info->userhdr;
987
	struct sw_flow_key key;
988 989 990 991
	struct sw_flow *flow;
	struct sw_flow_mask mask;
	struct sk_buff *reply = NULL;
	struct datapath *dp;
992
	struct sw_flow_actions *old_acts = NULL, *acts = NULL;
993 994 995 996 997
	struct sw_flow_match match;
	int error;

	/* Extract key. */
	error = -EINVAL;
998 999
	if (!a[OVS_FLOW_ATTR_KEY]) {
		OVS_NLERR("Flow key attribute not present in set flow.\n");
1000
		goto error;
1001
	}
1002 1003 1004 1005 1006 1007 1008 1009 1010

	ovs_match_init(&match, &key, &mask);
	error = ovs_nla_get_match(&match,
				  a[OVS_FLOW_ATTR_KEY], a[OVS_FLOW_ATTR_MASK]);
	if (error)
		goto error;

	/* Validate actions. */
	if (a[OVS_FLOW_ATTR_ACTIONS]) {
1011 1012 1013
		acts = get_flow_actions(a[OVS_FLOW_ATTR_ACTIONS], &key, &mask);
		if (IS_ERR(acts)) {
			error = PTR_ERR(acts);