// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2007-2014 Nicira, Inc.
 */

#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>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

#include "datapath.h"
#include "flow.h"
#include "flow_table.h"
#include "flow_netlink.h"
#include "meter.h"
#include "openvswitch_trace.h"
#include "vport-internal_dev.h"
#include "vport-netdev.h"

unsigned int ovs_net_id __read_mostly;

static struct genl_family dp_packet_genl_family;
static struct genl_family dp_flow_genl_family;
static struct genl_family dp_datapath_genl_family;

static const struct nla_policy flow_policy[];

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

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

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

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

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

/**
 * DOC: Locking:
 *
 * 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.
 *
 * 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.
 *
 * The RTNL lock nests inside ovs_mutex.
 */

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;
}
#endif

static struct vport *new_vport(const struct vport_parms *);
static int queue_gso_packets(struct datapath *dp, struct sk_buff *,
                             const struct sw_flow_key *,
                             const struct dp_upcall_info *,
                             uint32_t cutlen);
static int queue_userspace_packet(struct datapath *dp, struct sk_buff *,
                                  const struct sw_flow_key *,
                                  const struct dp_upcall_info *,
                                  uint32_t cutlen);

static void ovs_dp_masks_rebalance(struct work_struct *work);

static int ovs_dp_set_upcall_portids(struct datapath *, const struct nlattr *);

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

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

        rcu_read_lock();

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

        ovs_flow_tbl_destroy(&dp->table);
        free_percpu(dp->stats_percpu);
        kfree(dp->ports);
        ovs_meters_exit(dp);
        kfree(rcu_dereference_raw(dp->upcall_portids));
        kfree(dp);
}

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

/* Called with ovs_mutex or RCU read lock. */
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);
        hlist_for_each_entry_rcu(vport, head, dp_hash_node,
                                 lockdep_ovsl_is_held()) {
                if (vport->port_no == port_no)
                        return vport;
        }
        return NULL;
}

/* Called with ovs_mutex. */
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;
                struct hlist_head *head = vport_hash_bucket(dp, vport->port_no);

                hlist_add_head_rcu(&vport->dp_hash_node, head);
        }
        return vport;
}

void ovs_dp_detach_port(struct vport *p)
{
        ASSERT_OVSL();

        /* First drop references to device. */
        hlist_del_rcu(&p->dp_hash_node);

        /* Then destroy it. */
        ovs_vport_del(p);
}

/* Must be called with rcu_read_lock. */
void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key)
{
        const struct vport *p = OVS_CB(skb)->input_vport;
        struct datapath *dp = p->dp;
        struct sw_flow *flow;
        struct sw_flow_actions *sf_acts;
        struct dp_stats_percpu *stats;
        u64 *stats_counter;
        u32 n_mask_hit;
        u32 n_cache_hit;
        int error;

        stats = this_cpu_ptr(dp->stats_percpu);

        /* Look up flow. */
        flow = ovs_flow_tbl_lookup_stats(&dp->table, key, skb_get_hash(skb),
                                         &n_mask_hit, &n_cache_hit);
        if (unlikely(!flow)) {
                struct dp_upcall_info upcall;

                memset(&upcall, 0, sizeof(upcall));
                upcall.cmd = OVS_PACKET_CMD_MISS;

                if (dp->user_features & OVS_DP_F_DISPATCH_UPCALL_PER_CPU)
                        upcall.portid =
                            ovs_dp_get_upcall_portid(dp, smp_processor_id());
                else
                        upcall.portid = ovs_vport_find_upcall_portid(p, skb);

                upcall.mru = OVS_CB(skb)->mru;
                error = ovs_dp_upcall(dp, skb, key, &upcall, 0);
                if (unlikely(error))
                        kfree_skb(skb);
                else
                        consume_skb(skb);
                stats_counter = &stats->n_missed;
                goto out;
        }

        ovs_flow_stats_update(flow, key->tp.flags, skb);
        sf_acts = rcu_dereference(flow->sf_acts);
        error = ovs_execute_actions(dp, skb, sf_acts, key);
        if (unlikely(error))
                net_dbg_ratelimited("ovs: action execution error on datapath %s: %d\n",
                                    ovs_dp_name(dp), error);

        stats_counter = &stats->n_hit;

out:
        /* Update datapath statistics. */
        u64_stats_update_begin(&stats->syncp);
        (*stats_counter)++;
        stats->n_mask_hit += n_mask_hit;
        stats->n_cache_hit += n_cache_hit;
        u64_stats_update_end(&stats->syncp);
}

int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
                  const struct sw_flow_key *key,
                  const struct dp_upcall_info *upcall_info,
                  uint32_t cutlen)
{
        struct dp_stats_percpu *stats;
        int err;

        if (trace_ovs_dp_upcall_enabled())
                trace_ovs_dp_upcall(dp, skb, key, upcall_info);

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

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

        return 0;

err:
        stats = this_cpu_ptr(dp->stats_percpu);

        u64_stats_update_begin(&stats->syncp);
        stats->n_lost++;
        u64_stats_update_end(&stats->syncp);

        return err;
}

static int queue_gso_packets(struct datapath *dp, struct sk_buff *skb,
                             const struct sw_flow_key *key,
                             const struct dp_upcall_info *upcall_info,
                             uint32_t cutlen)
{
        unsigned int gso_type = skb_shinfo(skb)->gso_type;
        struct sw_flow_key later_key;
        struct sk_buff *segs, *nskb;
        int err;

        BUILD_BUG_ON(sizeof(*OVS_CB(skb)) > SKB_GSO_CB_OFFSET);
        segs = __skb_gso_segment(skb, NETIF_F_SG, false);
        if (IS_ERR(segs))
                return PTR_ERR(segs);
        if (segs == NULL)
                return -EINVAL;

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

        /* Queue all of the segments. */
        skb_list_walk_safe(segs, skb, nskb) {
                if (gso_type & SKB_GSO_UDP && skb != segs)
                        key = &later_key;

                err = queue_userspace_packet(dp, skb, key, upcall_info, cutlen);
                if (err)
                        break;

        }

        /* Free all of the segments. */
        skb_list_walk_safe(segs, skb, nskb) {
                if (err)
                        kfree_skb(skb);
                else
                        consume_skb(skb);
        }
        return err;
}

static size_t upcall_msg_size(const struct dp_upcall_info *upcall_info,
                              unsigned int hdrlen, int actions_attrlen)
{
        size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
                + nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */
                + nla_total_size(ovs_key_attr_size()) /* OVS_PACKET_ATTR_KEY */
                + nla_total_size(sizeof(unsigned int)) /* OVS_PACKET_ATTR_LEN */
                + nla_total_size(sizeof(u64)); /* OVS_PACKET_ATTR_HASH */

        /* OVS_PACKET_ATTR_USERDATA */
        if (upcall_info->userdata)
                size += NLA_ALIGN(upcall_info->userdata->nla_len);

        /* OVS_PACKET_ATTR_EGRESS_TUN_KEY */
        if (upcall_info->egress_tun_info)
                size += nla_total_size(ovs_tun_key_attr_size());

        /* OVS_PACKET_ATTR_ACTIONS */
        if (upcall_info->actions_len)
                size += nla_total_size(actions_attrlen);

        /* OVS_PACKET_ATTR_MRU */
        if (upcall_info->mru)
                size += nla_total_size(sizeof(upcall_info->mru));

        return size;
}

static void pad_packet(struct datapath *dp, struct sk_buff *skb)
{
        if (!(dp->user_features & OVS_DP_F_UNALIGNED)) {
                size_t plen = NLA_ALIGN(skb->len) - skb->len;

                if (plen > 0)
                        skb_put_zero(skb, plen);
        }
}

static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
                                  const struct sw_flow_key *key,
                                  const struct dp_upcall_info *upcall_info,
                                  uint32_t cutlen)
{
        struct ovs_header *upcall;
        struct sk_buff *nskb = NULL;
        struct sk_buff *user_skb = NULL; /* to be queued to userspace */
        struct nlattr *nla;
        size_t len;
        unsigned int hlen;
        int err, dp_ifindex;
        u64 hash;

        dp_ifindex = get_dpifindex(dp);
        if (!dp_ifindex)
                return -ENODEV;

        if (skb_vlan_tag_present(skb)) {
                nskb = skb_clone(skb, GFP_ATOMIC);
                if (!nskb)
                        return -ENOMEM;

                nskb = __vlan_hwaccel_push_inside(nskb);
                if (!nskb)
                        return -ENOMEM;

                skb = nskb;
        }

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

        /* Complete checksum if needed */
        if (skb->ip_summed == CHECKSUM_PARTIAL &&
            (err = skb_csum_hwoffload_help(skb, 0)))
                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, hlen - cutlen,
                              OVS_CB(skb)->acts_origlen);
        user_skb = genlmsg_new(len, GFP_ATOMIC);
        if (!user_skb) {
                err = -ENOMEM;
                goto out;
        }

        upcall = genlmsg_put(user_skb, 0, 0, &dp_packet_genl_family,
                             0, upcall_info->cmd);
        if (!upcall) {
                err = -EINVAL;
                goto out;
        }
        upcall->dp_ifindex = dp_ifindex;

        err = ovs_nla_put_key(key, key, OVS_PACKET_ATTR_KEY, false, user_skb);
        if (err)
                goto out;

        if (upcall_info->userdata)
                __nla_put(user_skb, OVS_PACKET_ATTR_USERDATA,
                          nla_len(upcall_info->userdata),
                          nla_data(upcall_info->userdata));

        if (upcall_info->egress_tun_info) {
                nla = nla_nest_start_noflag(user_skb,
                                            OVS_PACKET_ATTR_EGRESS_TUN_KEY);
                if (!nla) {
                        err = -EMSGSIZE;
                        goto out;
                }
                err = ovs_nla_put_tunnel_info(user_skb,
                                              upcall_info->egress_tun_info);
                if (err)
                        goto out;

                nla_nest_end(user_skb, nla);
        }

        if (upcall_info->actions_len) {
                nla = nla_nest_start_noflag(user_skb, OVS_PACKET_ATTR_ACTIONS);
                if (!nla) {
                        err = -EMSGSIZE;
                        goto out;
                }
                err = ovs_nla_put_actions(upcall_info->actions,
                                          upcall_info->actions_len,
                                          user_skb);
                if (!err)
                        nla_nest_end(user_skb, nla);
                else
                        nla_nest_cancel(user_skb, nla);
        }

        /* Add OVS_PACKET_ATTR_MRU */
        if (upcall_info->mru &&
            nla_put_u16(user_skb, OVS_PACKET_ATTR_MRU, upcall_info->mru)) {
                err = -ENOBUFS;
                goto out;
        }

        /* Add OVS_PACKET_ATTR_LEN when packet is truncated */
        if (cutlen > 0 &&
            nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN, skb->len)) {
                err = -ENOBUFS;
                goto out;
        }

        /* Add OVS_PACKET_ATTR_HASH */
        hash = skb_get_hash_raw(skb);
        if (skb->sw_hash)
                hash |= OVS_PACKET_HASH_SW_BIT;

        if (skb->l4_hash)
                hash |= OVS_PACKET_HASH_L4_BIT;

        if (nla_put(user_skb, OVS_PACKET_ATTR_HASH, sizeof (u64), &hash)) {
                err = -ENOBUFS;
                goto out;
        }

        /* 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 - cutlen);

        err = skb_zerocopy(user_skb, skb, skb->len - cutlen, hlen);
        if (err)
                goto out;

        /* Pad OVS_PACKET_ATTR_PACKET if linear copy was performed */
        pad_packet(dp, user_skb);

        ((struct nlmsghdr *) user_skb->data)->nlmsg_len = user_skb->len;

        err = genlmsg_unicast(ovs_dp_get_net(dp), user_skb, upcall_info->portid);
        user_skb = NULL;
out:
        if (err)
                skb_tx_error(skb);
        kfree_skb(user_skb);
        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 net *net = sock_net(skb->sk);
        struct nlattr **a = info->attrs;
        struct sw_flow_actions *acts;
        struct sk_buff *packet;
        struct sw_flow *flow;
        struct sw_flow_actions *sf_acts;
        struct datapath *dp;
        struct vport *input_vport;
        u16 mru = 0;
        u64 hash;
        int len;
        int err;
        bool log = !a[OVS_PACKET_ATTR_PROBE];

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

        nla_memcpy(__skb_put(packet, len), a[OVS_PACKET_ATTR_PACKET], len);

        /* Set packet's mru */
        if (a[OVS_PACKET_ATTR_MRU]) {
                mru = nla_get_u16(a[OVS_PACKET_ATTR_MRU]);
                packet->ignore_df = 1;
        }
        OVS_CB(packet)->mru = mru;

        if (a[OVS_PACKET_ATTR_HASH]) {
                hash = nla_get_u64(a[OVS_PACKET_ATTR_HASH]);

                __skb_set_hash(packet, hash & 0xFFFFFFFFULL,
                               !!(hash & OVS_PACKET_HASH_SW_BIT),
                               !!(hash & OVS_PACKET_HASH_L4_BIT));
        }

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

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

        err = ovs_nla_copy_actions(net, a[OVS_PACKET_ATTR_ACTIONS],
                                   &flow->key, &acts, log);
        if (err)
                goto err_flow_free;

        rcu_assign_pointer(flow->sf_acts, acts);
        packet->priority = flow->key.phy.priority;
        packet->mark = flow->key.phy.skb_mark;

        rcu_read_lock();
        dp = get_dp_rcu(net, ovs_header->dp_ifindex);
        err = -ENODEV;
        if (!dp)
                goto err_unlock;

        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;

        packet->dev = input_vport->dev;
        OVS_CB(packet)->input_vport = input_vport;
        sf_acts = rcu_dereference(flow->sf_acts);

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

        ovs_flow_free(flow, false);
        return err;

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

static const struct nla_policy packet_policy[OVS_PACKET_ATTR_MAX + 1] = {
        [OVS_PACKET_ATTR_PACKET] = { .len = ETH_HLEN },
        [OVS_PACKET_ATTR_KEY] = { .type = NLA_NESTED },
        [OVS_PACKET_ATTR_ACTIONS] = { .type = NLA_NESTED },
        [OVS_PACKET_ATTR_PROBE] = { .type = NLA_FLAG },
        [OVS_PACKET_ATTR_MRU] = { .type = NLA_U16 },
        [OVS_PACKET_ATTR_HASH] = { .type = NLA_U64 },
};

static const struct genl_small_ops dp_packet_genl_ops[] = {
        { .cmd = OVS_PACKET_CMD_EXECUTE,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_packet_cmd_execute
        }
};

static struct genl_family dp_packet_genl_family __ro_after_init = {
        .hdrsize = sizeof(struct ovs_header),
        .name = OVS_PACKET_FAMILY,
        .version = OVS_PACKET_VERSION,
        .maxattr = OVS_PACKET_ATTR_MAX,
        .policy = packet_policy,
        .netnsok = true,
        .parallel_ops = true,
        .small_ops = dp_packet_genl_ops,
        .n_small_ops = ARRAY_SIZE(dp_packet_genl_ops),
        .module = THIS_MODULE,
};

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

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

        stats->n_flows = ovs_flow_tbl_count(&dp->table);
        mega_stats->n_masks = ovs_flow_tbl_num_masks(&dp->table);

        stats->n_hit = stats->n_missed = stats->n_lost = 0;

        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 {
                        start = u64_stats_fetch_begin_irq(&percpu_stats->syncp);
                        local_stats = *percpu_stats;
                } while (u64_stats_fetch_retry_irq(&percpu_stats->syncp, start));

                stats->n_hit += local_stats.n_hit;
                stats->n_missed += local_stats.n_missed;
                stats->n_lost += local_stats.n_lost;
                mega_stats->n_mask_hit += local_stats.n_mask_hit;
                mega_stats->n_cache_hit += local_stats.n_cache_hit;
        }
}

static bool should_fill_key(const struct sw_flow_id *sfid, uint32_t ufid_flags)
{
        return ovs_identifier_is_ufid(sfid) &&
               !(ufid_flags & OVS_UFID_F_OMIT_KEY);
}

static bool should_fill_mask(uint32_t ufid_flags)
{
        return !(ufid_flags & OVS_UFID_F_OMIT_MASK);
}

static bool should_fill_actions(uint32_t ufid_flags)
{
        return !(ufid_flags & OVS_UFID_F_OMIT_ACTIONS);
}

static size_t ovs_flow_cmd_msg_size(const struct sw_flow_actions *acts,
                                    const struct sw_flow_id *sfid,
                                    uint32_t ufid_flags)
{
        size_t len = NLMSG_ALIGN(sizeof(struct ovs_header));

        /* OVS_FLOW_ATTR_UFID, or unmasked flow key as fallback
         * see ovs_nla_put_identifier()
         */
        if (sfid && ovs_identifier_is_ufid(sfid))
                len += nla_total_size(sfid->ufid_len);
        else
                len += nla_total_size(ovs_key_attr_size());

        /* OVS_FLOW_ATTR_KEY */
        if (!sfid || should_fill_key(sfid, ufid_flags))
                len += nla_total_size(ovs_key_attr_size());

        /* OVS_FLOW_ATTR_MASK */
        if (should_fill_mask(ufid_flags))
                len += nla_total_size(ovs_key_attr_size());

        /* OVS_FLOW_ATTR_ACTIONS */
        if (should_fill_actions(ufid_flags))
                len += nla_total_size(acts->orig_len);

        return len
                + nla_total_size_64bit(sizeof(struct ovs_flow_stats)) /* OVS_FLOW_ATTR_STATS */
                + nla_total_size(1) /* OVS_FLOW_ATTR_TCP_FLAGS */
                + nla_total_size_64bit(8); /* OVS_FLOW_ATTR_USED */
}

/* 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;

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

        if (used &&
            nla_put_u64_64bit(skb, OVS_FLOW_ATTR_USED, ovs_flow_used_time(used),
                              OVS_FLOW_ATTR_PAD))
                return -EMSGSIZE;

        if (stats.n_packets &&
            nla_put_64bit(skb, OVS_FLOW_ATTR_STATS,
                          sizeof(struct ovs_flow_stats), &stats,
                          OVS_FLOW_ATTR_PAD))
                return -EMSGSIZE;

        if ((u8)ntohs(tcp_flags) &&
             nla_put_u8(skb, OVS_FLOW_ATTR_TCP_FLAGS, (u8)ntohs(tcp_flags)))
                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;

        /* 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.
         */
        start = nla_nest_start_noflag(skb, OVS_FLOW_ATTR_ACTIONS);
        if (start) {
                const struct sw_flow_actions *sf_acts;

                sf_acts = rcu_dereference_ovsl(flow->sf_acts);
                err = ovs_nla_put_actions(sf_acts->actions,
                                          sf_acts->actions_len, skb);

                if (!err)
                        nla_nest_end(skb, start);
                else {
                        if (skb_orig_len)
                                return err;

                        nla_nest_cancel(skb, start);
                }
        } 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, u32 ufid_flags)
{
        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_nla_put_identifier(flow, skb);
        if (err)
                goto error;

        if (should_fill_key(&flow->id, ufid_flags)) {
                err = ovs_nla_put_masked_key(flow, skb);
                if (err)
                        goto error;
        }

        if (should_fill_mask(ufid_flags)) {
                err = ovs_nla_put_mask(flow, skb);
                if (err)
                        goto error;
        }

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

        if (should_fill_actions(ufid_flags)) {
                err = ovs_flow_cmd_fill_actions(flow, skb, skb_orig_len);
                if (err)
                        goto error;
        }

        genlmsg_end(skb, ovs_header);
        return 0;

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

/* May not be called with RCU read lock. */
static struct sk_buff *ovs_flow_cmd_alloc_info(const struct sw_flow_actions *acts,
                                               const struct sw_flow_id *sfid,
                                               struct genl_info *info,
                                               bool always,
                                               uint32_t ufid_flags)
{
        struct sk_buff *skb;
        size_t len;

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

        len = ovs_flow_cmd_msg_size(acts, sfid, ufid_flags);
        skb = genlmsg_new(len, GFP_KERNEL);
        if (!skb)
                return ERR_PTR(-ENOMEM);

        return skb;
}

/* 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, u32 ufid_flags)
{
        struct sk_buff *skb;
        int retval;

        skb = ovs_flow_cmd_alloc_info(ovsl_dereference(flow->sf_acts),
                                      &flow->id, info, always, ufid_flags);
        if (IS_ERR_OR_NULL(skb))
                return skb;

        retval = ovs_flow_cmd_fill_info(flow, dp_ifindex, skb,
                                        info->snd_portid, info->snd_seq, 0,
                                        cmd, ufid_flags);
        if (WARN_ON_ONCE(retval < 0)) {
                kfree_skb(skb);
                skb = ERR_PTR(retval);
        }
        return skb;
}

static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = sock_net(skb->sk);
        struct nlattr **a = info->attrs;
        struct ovs_header *ovs_header = info->userhdr;
        struct sw_flow *flow = NULL, *new_flow;
        struct sw_flow_mask mask;
        struct sk_buff *reply;
        struct datapath *dp;
        struct sw_flow_actions *acts;
        struct sw_flow_match match;
        u32 ufid_flags = ovs_nla_get_ufid_flags(a[OVS_FLOW_ATTR_UFID_FLAGS]);
        int error;
        bool log = !a[OVS_FLOW_ATTR_PROBE];

        /* Must have key and actions. */
        error = -EINVAL;
        if (!a[OVS_FLOW_ATTR_KEY]) {
                OVS_NLERR(log, "Flow key attr not present in new flow.");
                goto error;
        }
        if (!a[OVS_FLOW_ATTR_ACTIONS]) {
                OVS_NLERR(log, "Flow actions attr not present in new flow.");
                goto error;
        }

        /* 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->key, false, &mask);
        error = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY],
                                  a[OVS_FLOW_ATTR_MASK], log);
        if (error)
                goto err_kfree_flow;

        /* Extract flow identifier. */
        error = ovs_nla_get_identifier(&new_flow->id, a[OVS_FLOW_ATTR_UFID],
                                       &new_flow->key, log);
        if (error)
                goto err_kfree_flow;

        /* unmasked key is needed to match when ufid is not used. */
        if (ovs_identifier_is_key(&new_flow->id))
                match.key = new_flow->id.unmasked_key;

        ovs_flow_mask_key(&new_flow->key, &new_flow->key, true, &mask);

        /* Validate actions. */
        error = ovs_nla_copy_actions(net, a[OVS_FLOW_ATTR_ACTIONS],
                                     &new_flow->key, &acts, log);
        if (error) {
                OVS_NLERR(log, "Flow actions may not be safe on all matching packets.");
                goto err_kfree_flow;
        }

        reply = ovs_flow_cmd_alloc_info(acts, &new_flow->id, info, false,
                                        ufid_flags);
        if (IS_ERR(reply)) {
                error = PTR_ERR(reply);
                goto err_kfree_acts;
        }

        ovs_lock();
        dp = get_dp(net, ovs_header->dp_ifindex);
        if (unlikely(!dp)) {
                error = -ENODEV;
                goto err_unlock_ovs;
        }

        /* Check if this is a duplicate flow */
        if (ovs_identifier_is_ufid(&new_flow->id))
                flow = ovs_flow_tbl_lookup_ufid(&dp->table, &new_flow->id);
        if (!flow)
                flow = ovs_flow_tbl_lookup(&dp->table, &new_flow->key);
        if (likely(!flow)) {
                rcu_assign_pointer(new_flow->sf_acts, acts);

                /* Put flow in bucket. */
                error = ovs_flow_tbl_insert(&dp->table, new_flow, &mask);
                if (unlikely(error)) {
                        acts = NULL;
                        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,
                                                       ufid_flags);
                        BUG_ON(error < 0);
                }
                ovs_unlock();
        } else {
                struct sw_flow_actions *old_acts;

                /* 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.
                 */
                if (unlikely(info->nlhdr->nlmsg_flags & (NLM_F_CREATE
                                                         | NLM_F_EXCL))) {
                        error = -EEXIST;
                        goto err_unlock_ovs;
                }
                /* The flow identifier has to be the same for flow updates.
                 * Look for any overlapping flow.
                 */
                if (unlikely(!ovs_flow_cmp(flow, &match))) {
                        if (ovs_identifier_is_key(&flow->id))
                                flow = ovs_flow_tbl_lookup_exact(&dp->table,
                                                                 &match);
                        else /* UFID matches but key is different */
                                flow = NULL;
                        if (!flow) {
                                error = -ENOENT;
                                goto err_unlock_ovs;
                        }
                }
                /* Update actions. */
                old_acts = ovsl_dereference(flow->sf_acts);
                rcu_assign_pointer(flow->sf_acts, acts);

                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,
                                                       ufid_flags);
                        BUG_ON(error < 0);
                }
                ovs_unlock();

                ovs_nla_free_flow_actions_rcu(old_acts);
                ovs_flow_free(new_flow, false);
        }

        if (reply)
                ovs_notify(&dp_flow_genl_family, reply, info);
        return 0;

err_unlock_ovs:
        ovs_unlock();
        kfree_skb(reply);
err_kfree_acts:
        ovs_nla_free_flow_actions(acts);
err_kfree_flow:
        ovs_flow_free(new_flow, false);
error:
        return error;
}

/* Factor out action copy to avoid "Wframe-larger-than=1024" warning. */
static noinline_for_stack
struct sw_flow_actions *get_flow_actions(struct net *net,
                                         const struct nlattr *a,
                                         const struct sw_flow_key *key,
                                         const struct sw_flow_mask *mask,
                                         bool log)
{
        struct sw_flow_actions *acts;
        struct sw_flow_key masked_key;
        int error;

        ovs_flow_mask_key(&masked_key, key, true, mask);
        error = ovs_nla_copy_actions(net, a, &masked_key, &acts, log);
        if (error) {
                OVS_NLERR(log,
                          "Actions may not be safe on all matching packets");
                return ERR_PTR(error);
        }

        return acts;
}

/* Factor out match-init and action-copy to avoid
 * "Wframe-larger-than=1024" warning. Because mask is only
 * used to get actions, we new a function to save some
 * stack space.
 *
 * If there are not key and action attrs, we return 0
 * directly. In the case, the caller will also not use the
 * match as before. If there is action attr, we try to get
 * actions and save them to *acts. Before returning from
 * the function, we reset the match->mask pointer. Because
 * we should not to return match object with dangling reference
 * to mask.
 * */
static noinline_for_stack int
ovs_nla_init_match_and_action(struct net *net,
                              struct sw_flow_match *match,
                              struct sw_flow_key *key,
                              struct nlattr **a,
                              struct sw_flow_actions **acts,
                              bool log)
{
        struct sw_flow_mask mask;
        int error = 0;

        if (a[OVS_FLOW_ATTR_KEY]) {
                ovs_match_init(match, key, true, &mask);
                error = ovs_nla_get_match(net, match, a[OVS_FLOW_ATTR_KEY],
                                          a[OVS_FLOW_ATTR_MASK], log);
                if (error)
                        goto error;
        }

        if (a[OVS_FLOW_ATTR_ACTIONS]) {
                if (!a[OVS_FLOW_ATTR_KEY]) {
                        OVS_NLERR(log,
                                  "Flow key attribute not present in set flow.");
                        error = -EINVAL;
                        goto error;
                }

                *acts = get_flow_actions(net, a[OVS_FLOW_ATTR_ACTIONS], key,
                                         &mask, log);
                if (IS_ERR(*acts)) {
                        error = PTR_ERR(*acts);
                        goto error;
                }
        }

        /* On success, error is 0. */
error:
        match->mask = NULL;
        return error;
}

static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = sock_net(skb->sk);
        struct nlattr **a = info->attrs;
        struct ovs_header *ovs_header = info->userhdr;
        struct sw_flow_key key;
        struct sw_flow *flow;
        struct sk_buff *reply = NULL;
        struct datapath *dp;
        struct sw_flow_actions *old_acts = NULL, *acts = NULL;
        struct sw_flow_match match;
        struct sw_flow_id sfid;
        u32 ufid_flags = ovs_nla_get_ufid_flags(a[OVS_FLOW_ATTR_UFID_FLAGS]);
        int error = 0;
        bool log = !a[OVS_FLOW_ATTR_PROBE];
        bool ufid_present;

        ufid_present = ovs_nla_get_ufid(&sfid, a[OVS_FLOW_ATTR_UFID], log);
        if (!a[OVS_FLOW_ATTR_KEY] && !ufid_present) {
                OVS_NLERR(log,
                          "Flow set message rejected, Key attribute missing.");
                return -EINVAL;
        }

        error = ovs_nla_init_match_and_action(net, &match, &key, a,
                                              &acts, log);
        if (error)
                goto error;

        if (acts) {
                /* Can allocate before locking if have acts. */
                reply = ovs_flow_cmd_alloc_info(acts, &sfid, info, false,
                                                ufid_flags);
                if (IS_ERR(reply)) {
                        error = PTR_ERR(reply);
                        goto err_kfree_acts;
                }
        }

        ovs_lock();
        dp = get_dp(net, ovs_header->dp_ifindex);
        if (unlikely(!dp)) {
                error = -ENODEV;
                goto err_unlock_ovs;
        }
        /* Check that the flow exists. */
        if (ufid_present)
                flow = ovs_flow_tbl_lookup_ufid(&dp->table, &sfid);
        else
                flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
        if (unlikely(!flow)) {
                error = -ENOENT;
                goto err_unlock_ovs;
        }

        /* Update actions, if present. */
        if (likely(acts)) {
                old_acts = ovsl_dereference(flow->sf_acts);
                rcu_assign_pointer(flow->sf_acts, acts);

                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_SET,
                                                       ufid_flags);
                        BUG_ON(error < 0);
                }
        } else {
                /* Could not alloc without acts before locking. */
                reply = ovs_flow_cmd_build_info(flow, ovs_header->dp_ifindex,
                                                info, OVS_FLOW_CMD_SET, false,
                                                ufid_flags);

                if (IS_ERR(reply)) {
                        error = PTR_ERR(reply);
                        goto err_unlock_ovs;
                }
        }

        /* Clear stats. */
        if (a[OVS_FLOW_ATTR_CLEAR])
                ovs_flow_stats_clear(flow);
        ovs_unlock();

        if (reply)
                ovs_notify(&dp_flow_genl_family, reply, info);
        if (old_acts)
                ovs_nla_free_flow_actions_rcu(old_acts);

        return 0;

err_unlock_ovs:
        ovs_unlock();
        kfree_skb(reply);
err_kfree_acts:
        ovs_nla_free_flow_actions(acts);
error:
        return error;
}

static int ovs_flow_cmd_get(struct sk_buff *skb, struct genl_info *info)
{
        struct nlattr **a = info->attrs;
        struct ovs_header *ovs_header = info->userhdr;
        struct net *net = sock_net(skb->sk);
        struct sw_flow_key key;
        struct sk_buff *reply;
        struct sw_flow *flow;
        struct datapath *dp;
        struct sw_flow_match match;
        struct sw_flow_id ufid;
        u32 ufid_flags = ovs_nla_get_ufid_flags(a[OVS_FLOW_ATTR_UFID_FLAGS]);
        int err = 0;
        bool log = !a[OVS_FLOW_ATTR_PROBE];
        bool ufid_present;

        ufid_present = ovs_nla_get_ufid(&ufid, a[OVS_FLOW_ATTR_UFID], log);
        if (a[OVS_FLOW_ATTR_KEY]) {
                ovs_match_init(&match, &key, true, NULL);
                err = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY], NULL,
                                        log);
        } else if (!ufid_present) {
                OVS_NLERR(log,
                          "Flow get message rejected, Key attribute missing.");
                err = -EINVAL;
        }
        if (err)
                return err;

        ovs_lock();
        dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
        if (!dp) {
                err = -ENODEV;
                goto unlock;
        }

        if (ufid_present)
                flow = ovs_flow_tbl_lookup_ufid(&dp->table, &ufid);
        else
                flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
        if (!flow) {
                err = -ENOENT;
                goto unlock;
        }

        reply = ovs_flow_cmd_build_info(flow, ovs_header->dp_ifindex, info,
                                        OVS_FLOW_CMD_GET, true, ufid_flags);
        if (IS_ERR(reply)) {
                err = PTR_ERR(reply);
                goto unlock;
        }

        ovs_unlock();
        return genlmsg_reply(reply, info);
unlock:
        ovs_unlock();
        return err;
}

static int ovs_flow_cmd_del(struct sk_buff *skb, struct genl_info *info)
{
        struct nlattr **a = info->attrs;
        struct ovs_header *ovs_header = info->userhdr;
        struct net *net = sock_net(skb->sk);
        struct sw_flow_key key;
        struct sk_buff *reply;
        struct sw_flow *flow = NULL;
        struct datapath *dp;
        struct sw_flow_match match;
        struct sw_flow_id ufid;
        u32 ufid_flags = ovs_nla_get_ufid_flags(a[OVS_FLOW_ATTR_UFID_FLAGS]);
        int err;
        bool log = !a[OVS_FLOW_ATTR_PROBE];
        bool ufid_present;

        ufid_present = ovs_nla_get_ufid(&ufid, a[OVS_FLOW_ATTR_UFID], log);
        if (a[OVS_FLOW_ATTR_KEY]) {
                ovs_match_init(&match, &key, true, NULL);
                err = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY],
                                        NULL, log);
                if (unlikely(err))
                        return err;
        }

        ovs_lock();
        dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
        if (unlikely(!dp)) {
                err = -ENODEV;
                goto unlock;
        }

        if (unlikely(!a[OVS_FLOW_ATTR_KEY] && !ufid_present)) {
                err = ovs_flow_tbl_flush(&dp->table);
                goto unlock;
        }

        if (ufid_present)
                flow = ovs_flow_tbl_lookup_ufid(&dp->table, &ufid);
        else
                flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
        if (unlikely(!flow)) {
                err = -ENOENT;
                goto unlock;
        }

        ovs_flow_tbl_remove(&dp->table, flow);
        ovs_unlock();

        reply = ovs_flow_cmd_alloc_info((const struct sw_flow_actions __force *) flow->sf_acts,
                                        &flow->id, info, false, ufid_flags);
        if (likely(reply)) {
                if (!IS_ERR(reply)) {
                        rcu_read_lock();        /*To keep RCU checker happy. */
                        err = ovs_flow_cmd_fill_info(flow, ovs_header->dp_ifindex,
                                                     reply, info->snd_portid,
                                                     info->snd_seq, 0,
                                                     OVS_FLOW_CMD_DEL,
                                                     ufid_flags);
                        rcu_read_unlock();
                        if (WARN_ON_ONCE(err < 0)) {
                                kfree_skb(reply);
                                goto out_free;
                        }

                        ovs_notify(&dp_flow_genl_family, reply, info);
                } else {
                        netlink_set_err(sock_net(skb->sk)->genl_sock, 0, 0,
                                        PTR_ERR(reply));
                }
        }

out_free:
        ovs_flow_free(flow, true);
        return 0;
unlock:
        ovs_unlock();
        return err;
}

static int ovs_flow_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct nlattr *a[__OVS_FLOW_ATTR_MAX];
        struct ovs_header *ovs_header = genlmsg_data(nlmsg_data(cb->nlh));
        struct table_instance *ti;
        struct datapath *dp;
        u32 ufid_flags;
        int err;

        err = genlmsg_parse_deprecated(cb->nlh, &dp_flow_genl_family, a,
                                       OVS_FLOW_ATTR_MAX, flow_policy, NULL);
        if (err)
                return err;
        ufid_flags = ovs_nla_get_ufid_flags(a[OVS_FLOW_ATTR_UFID_FLAGS]);

        rcu_read_lock();
        dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex);
        if (!dp) {
                rcu_read_unlock();
                return -ENODEV;
        }

        ti = rcu_dereference(dp->table.ti);
        for (;;) {
                struct sw_flow *flow;
                u32 bucket, obj;

                bucket = cb->args[0];
                obj = cb->args[1];
                flow = ovs_flow_tbl_dump_next(ti, &bucket, &obj);
                if (!flow)
                        break;

                if (ovs_flow_cmd_fill_info(flow, ovs_header->dp_ifindex, skb,
                                           NETLINK_CB(cb->skb).portid,
                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
                                           OVS_FLOW_CMD_GET, ufid_flags) < 0)
                        break;

                cb->args[0] = bucket;
                cb->args[1] = obj;
        }
        rcu_read_unlock();
        return skb->len;
}

static const struct nla_policy flow_policy[OVS_FLOW_ATTR_MAX + 1] = {
        [OVS_FLOW_ATTR_KEY] = { .type = NLA_NESTED },
        [OVS_FLOW_ATTR_MASK] = { .type = NLA_NESTED },
        [OVS_FLOW_ATTR_ACTIONS] = { .type = NLA_NESTED },
        [OVS_FLOW_ATTR_CLEAR] = { .type = NLA_FLAG },
        [OVS_FLOW_ATTR_PROBE] = { .type = NLA_FLAG },
        [OVS_FLOW_ATTR_UFID] = { .type = NLA_UNSPEC, .len = 1 },
        [OVS_FLOW_ATTR_UFID_FLAGS] = { .type = NLA_U32 },
};

static const struct genl_small_ops dp_flow_genl_ops[] = {
        { .cmd = OVS_FLOW_CMD_NEW,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_flow_cmd_new
        },
        { .cmd = OVS_FLOW_CMD_DEL,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_flow_cmd_del
        },
        { .cmd = OVS_FLOW_CMD_GET,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = 0,               /* OK for unprivileged users. */
          .doit = ovs_flow_cmd_get,
          .dumpit = ovs_flow_cmd_dump
        },
        { .cmd = OVS_FLOW_CMD_SET,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_flow_cmd_set,
        },
};

static struct genl_family dp_flow_genl_family __ro_after_init = {
        .hdrsize = sizeof(struct ovs_header),
        .name = OVS_FLOW_FAMILY,
        .version = OVS_FLOW_VERSION,
        .maxattr = OVS_FLOW_ATTR_MAX,
        .policy = flow_policy,
        .netnsok = true,
        .parallel_ops = true,
        .small_ops = dp_flow_genl_ops,
        .n_small_ops = ARRAY_SIZE(dp_flow_genl_ops),
        .mcgrps = &ovs_dp_flow_multicast_group,
        .n_mcgrps = 1,
        .module = THIS_MODULE,
};

static size_t ovs_dp_cmd_msg_size(void)
{
        size_t msgsize = NLMSG_ALIGN(sizeof(struct ovs_header));

        msgsize += nla_total_size(IFNAMSIZ);
        msgsize += nla_total_size_64bit(sizeof(struct ovs_dp_stats));
        msgsize += nla_total_size_64bit(sizeof(struct ovs_dp_megaflow_stats));
        msgsize += nla_total_size(sizeof(u32)); /* OVS_DP_ATTR_USER_FEATURES */
        msgsize += nla_total_size(sizeof(u32)); /* OVS_DP_ATTR_MASKS_CACHE_SIZE */

        return msgsize;
}

/* Called with ovs_mutex. */
static int ovs_dp_cmd_fill_info(struct datapath *dp, struct sk_buff *skb,
                                u32 portid, u32 seq, u32 flags, u8 cmd)
{
        struct ovs_header *ovs_header;
        struct ovs_dp_stats dp_stats;
        struct ovs_dp_megaflow_stats dp_megaflow_stats;
        int err;

        ovs_header = genlmsg_put(skb, portid, seq, &dp_datapath_genl_family,
                                 flags, cmd);
        if (!ovs_header)
                goto error;

        ovs_header->dp_ifindex = get_dpifindex(dp);

        err = nla_put_string(skb, OVS_DP_ATTR_NAME, ovs_dp_name(dp));
        if (err)
                goto nla_put_failure;

        get_dp_stats(dp, &dp_stats, &dp_megaflow_stats);
        if (nla_put_64bit(skb, OVS_DP_ATTR_STATS, sizeof(struct ovs_dp_stats),
                          &dp_stats, OVS_DP_ATTR_PAD))
                goto nla_put_failure;

        if (nla_put_64bit(skb, OVS_DP_ATTR_MEGAFLOW_STATS,
                          sizeof(struct ovs_dp_megaflow_stats),
                          &dp_megaflow_stats, OVS_DP_ATTR_PAD))
                goto nla_put_failure;

        if (nla_put_u32(skb, OVS_DP_ATTR_USER_FEATURES, dp->user_features))
                goto nla_put_failure;

        if (nla_put_u32(skb, OVS_DP_ATTR_MASKS_CACHE_SIZE,
                        ovs_flow_tbl_masks_cache_size(&dp->table)))
                goto nla_put_failure;

        genlmsg_end(skb, ovs_header);
        return 0;

nla_put_failure:
        genlmsg_cancel(skb, ovs_header);
error:
        return -EMSGSIZE;
}

static struct sk_buff *ovs_dp_cmd_alloc_info(void)
{
        return genlmsg_new(ovs_dp_cmd_msg_size(), GFP_KERNEL);
}

/* Called with rcu_read_lock or ovs_mutex. */
static struct datapath *lookup_datapath(struct net *net,
                                        const struct ovs_header *ovs_header,
                                        struct nlattr *a[OVS_DP_ATTR_MAX + 1])
{
        struct datapath *dp;

        if (!a[OVS_DP_ATTR_NAME])
                dp = get_dp(net, ovs_header->dp_ifindex);
        else {
                struct vport *vport;

                vport = ovs_vport_locate(net, nla_data(a[OVS_DP_ATTR_NAME]));
                dp = vport && vport->port_no == OVSP_LOCAL ? vport->dp : NULL;
        }
        return dp ? dp : ERR_PTR(-ENODEV);
}

static void ovs_dp_reset_user_features(struct sk_buff *skb,
                                       struct genl_info *info)
{
        struct datapath *dp;

        dp = lookup_datapath(sock_net(skb->sk), info->userhdr,
                             info->attrs);
        if (IS_ERR(dp))
                return;

        WARN(dp->user_features, "Dropping previously announced user features\n");
        dp->user_features = 0;
}

DEFINE_STATIC_KEY_FALSE(tc_recirc_sharing_support);

static int ovs_dp_set_upcall_portids(struct datapath *dp,
                              const struct nlattr *ids)
{
        struct dp_nlsk_pids *old, *dp_nlsk_pids;

        if (!nla_len(ids) || nla_len(ids) % sizeof(u32))
                return -EINVAL;

        old = ovsl_dereference(dp->upcall_portids);

        dp_nlsk_pids = kmalloc(sizeof(*dp_nlsk_pids) + nla_len(ids),
                               GFP_KERNEL);
        if (!dp_nlsk_pids)
                return -ENOMEM;

        dp_nlsk_pids->n_pids = nla_len(ids) / sizeof(u32);
        nla_memcpy(dp_nlsk_pids->pids, ids, nla_len(ids));

        rcu_assign_pointer(dp->upcall_portids, dp_nlsk_pids);

        kfree_rcu(old, rcu);

        return 0;
}

u32 ovs_dp_get_upcall_portid(const struct datapath *dp, uint32_t cpu_id)
{
        struct dp_nlsk_pids *dp_nlsk_pids;

        dp_nlsk_pids = rcu_dereference(dp->upcall_portids);

        if (dp_nlsk_pids) {
                if (cpu_id < dp_nlsk_pids->n_pids) {
                        return dp_nlsk_pids->pids[cpu_id];
                } else if (dp_nlsk_pids->n_pids > 0 &&
                           cpu_id >= dp_nlsk_pids->n_pids) {
                        /* If the number of netlink PIDs is mismatched with
                         * the number of CPUs as seen by the kernel, log this
                         * and send the upcall to an arbitrary socket (0) in
                         * order to not drop packets
                         */
                        pr_info_ratelimited("cpu_id mismatch with handler threads");
                        return dp_nlsk_pids->pids[cpu_id %
                                                  dp_nlsk_pids->n_pids];
                } else {
                        return 0;
                }
        } else {
                return 0;
        }
}

static int ovs_dp_change(struct datapath *dp, struct nlattr *a[])
{
        u32 user_features = 0;
        int err;

        if (a[OVS_DP_ATTR_USER_FEATURES]) {
                user_features = nla_get_u32(a[OVS_DP_ATTR_USER_FEATURES]);

                if (user_features & ~(OVS_DP_F_VPORT_PIDS |
                                      OVS_DP_F_UNALIGNED |
                                      OVS_DP_F_TC_RECIRC_SHARING |
                                      OVS_DP_F_DISPATCH_UPCALL_PER_CPU))
                        return -EOPNOTSUPP;

#if !IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
                if (user_features & OVS_DP_F_TC_RECIRC_SHARING)
                        return -EOPNOTSUPP;
#endif
        }

        if (a[OVS_DP_ATTR_MASKS_CACHE_SIZE]) {
                int err;
                u32 cache_size;

                cache_size = nla_get_u32(a[OVS_DP_ATTR_MASKS_CACHE_SIZE]);
                err = ovs_flow_tbl_masks_cache_resize(&dp->table, cache_size);
                if (err)
                        return err;
        }

        dp->user_features = user_features;

        if (dp->user_features & OVS_DP_F_DISPATCH_UPCALL_PER_CPU &&
            a[OVS_DP_ATTR_PER_CPU_PIDS]) {
                /* Upcall Netlink Port IDs have been updated */
                err = ovs_dp_set_upcall_portids(dp,
                                                a[OVS_DP_ATTR_PER_CPU_PIDS]);
                if (err)
                        return err;
        }

        if (dp->user_features & OVS_DP_F_TC_RECIRC_SHARING)
                static_branch_enable(&tc_recirc_sharing_support);
        else
                static_branch_disable(&tc_recirc_sharing_support);

        return 0;
}

static int ovs_dp_stats_init(struct datapath *dp)
{
        dp->stats_percpu = netdev_alloc_pcpu_stats(struct dp_stats_percpu);
        if (!dp->stats_percpu)
                return -ENOMEM;

        return 0;
}

static int ovs_dp_vport_init(struct datapath *dp)
{
        int i;

        dp->ports = kmalloc_array(DP_VPORT_HASH_BUCKETS,
                                  sizeof(struct hlist_head),
                                  GFP_KERNEL);
        if (!dp->ports)
                return -ENOMEM;

        for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++)
                INIT_HLIST_HEAD(&dp->ports[i]);

        return 0;
}

static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
{
        struct nlattr **a = info->attrs;
        struct vport_parms parms;
        struct sk_buff *reply;
        struct datapath *dp;
        struct vport *vport;
        struct ovs_net *ovs_net;
        int err;

        err = -EINVAL;
        if (!a[OVS_DP_ATTR_NAME] || !a[OVS_DP_ATTR_UPCALL_PID])
                goto err;

        reply = ovs_dp_cmd_alloc_info();
        if (!reply)
                return -ENOMEM;

        err = -ENOMEM;
        dp = kzalloc(sizeof(*dp), GFP_KERNEL);
        if (dp == NULL)
                goto err_destroy_reply;

        ovs_dp_set_net(dp, sock_net(skb->sk));

        /* Allocate table. */
        err = ovs_flow_tbl_init(&dp->table);
        if (err)
                goto err_destroy_dp;

        err = ovs_dp_stats_init(dp);
        if (err)
                goto err_destroy_table;

        err = ovs_dp_vport_init(dp);
        if (err)
                goto err_destroy_stats;

        err = ovs_meters_init(dp);
        if (err)
                goto err_destroy_ports;

        /* Set up our datapath device. */
        parms.name = nla_data(a[OVS_DP_ATTR_NAME]);
        parms.type = OVS_VPORT_TYPE_INTERNAL;
        parms.options = NULL;
        parms.dp = dp;
        parms.port_no = OVSP_LOCAL;
        parms.upcall_portids = a[OVS_DP_ATTR_UPCALL_PID];

        /* So far only local changes have been made, now need the lock. */
        ovs_lock();

        err = ovs_dp_change(dp, a);
        if (err)
                goto err_unlock_and_destroy_meters;

        vport = new_vport(&parms);
        if (IS_ERR(vport)) {
                err = PTR_ERR(vport);
                if (err == -EBUSY)
                        err = -EEXIST;

                if (err == -EEXIST) {
                        /* An outdated user space instance that does not understand
                         * the concept of user_features has attempted to create a new
                         * datapath and is likely to reuse it. Drop all user features.
                         */
                        if (info->genlhdr->version < OVS_DP_VER_FEATURES)
                                ovs_dp_reset_user_features(skb, info);
                }

                goto err_unlock_and_destroy_meters;
        }

        err = ovs_dp_cmd_fill_info(dp, reply, info->snd_portid,
                                   info->snd_seq, 0, OVS_DP_CMD_NEW);
        BUG_ON(err < 0);

        ovs_net = net_generic(ovs_dp_get_net(dp), ovs_net_id);
        list_add_tail_rcu(&dp->list_node, &ovs_net->dps);

        ovs_unlock();

        ovs_notify(&dp_datapath_genl_family, reply, info);
        return 0;

err_unlock_and_destroy_meters:
        ovs_unlock();
        ovs_meters_exit(dp);
err_destroy_ports:
        kfree(dp->ports);
err_destroy_stats:
        free_percpu(dp->stats_percpu);
err_destroy_table:
        ovs_flow_tbl_destroy(&dp->table);
err_destroy_dp:
        kfree(dp);
err_destroy_reply:
        kfree_skb(reply);
err:
        return err;
}

/* Called with ovs_mutex. */
static void __dp_destroy(struct datapath *dp)
{
        struct flow_table *table = &dp->table;
        int i;

        for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++) {
                struct vport *vport;
                struct hlist_node *n;

                hlist_for_each_entry_safe(vport, n, &dp->ports[i], dp_hash_node)
                        if (vport->port_no != OVSP_LOCAL)
                                ovs_dp_detach_port(vport);
        }

        list_del_rcu(&dp->list_node);

        /* OVSP_LOCAL is datapath internal port. We need to make sure that
         * all ports in datapath are destroyed first before freeing datapath.
         */
        ovs_dp_detach_port(ovs_vport_ovsl(dp, OVSP_LOCAL));

        /* Flush sw_flow in the tables. RCU cb only releases resource
         * such as dp, ports and tables. That may avoid some issues
         * such as RCU usage warning.
         */
        table_instance_flow_flush(table, ovsl_dereference(table->ti),
                                  ovsl_dereference(table->ufid_ti));

        /* RCU destroy the ports, meters and flow tables. */
        call_rcu(&dp->rcu, destroy_dp_rcu);
}

static int ovs_dp_cmd_del(struct sk_buff *skb, struct genl_info *info)
{
        struct sk_buff *reply;
        struct datapath *dp;
        int err;

        reply = ovs_dp_cmd_alloc_info();
        if (!reply)
                return -ENOMEM;

        ovs_lock();
        dp = lookup_datapath(sock_net(skb->sk), info->userhdr, info->attrs);
        err = PTR_ERR(dp);
        if (IS_ERR(dp))
                goto err_unlock_free;

        err = ovs_dp_cmd_fill_info(dp, reply, info->snd_portid,
                                   info->snd_seq, 0, OVS_DP_CMD_DEL);
        BUG_ON(err < 0);

        __dp_destroy(dp);
        ovs_unlock();

        ovs_notify(&dp_datapath_genl_family, reply, info);

        return 0;

err_unlock_free:
        ovs_unlock();
        kfree_skb(reply);
        return err;
}

static int ovs_dp_cmd_set(struct sk_buff *skb, struct genl_info *info)
{
        struct sk_buff *reply;
        struct datapath *dp;
        int err;

        reply = ovs_dp_cmd_alloc_info();
        if (!reply)
                return -ENOMEM;

        ovs_lock();
        dp = lookup_datapath(sock_net(skb->sk), info->userhdr, info->attrs);
        err = PTR_ERR(dp);
        if (IS_ERR(dp))
                goto err_unlock_free;

        err = ovs_dp_change(dp, info->attrs);
        if (err)
                goto err_unlock_free;

        err = ovs_dp_cmd_fill_info(dp, reply, info->snd_portid,
                                   info->snd_seq, 0, OVS_DP_CMD_SET);
        BUG_ON(err < 0);

        ovs_unlock();
        ovs_notify(&dp_datapath_genl_family, reply, info);

        return 0;

err_unlock_free:
        ovs_unlock();
        kfree_skb(reply);
        return err;
}

static int ovs_dp_cmd_get(struct sk_buff *skb, struct genl_info *info)
{
        struct sk_buff *reply;
        struct datapath *dp;
        int err;

        reply = ovs_dp_cmd_alloc_info();
        if (!reply)
                return -ENOMEM;

        ovs_lock();
        dp = lookup_datapath(sock_net(skb->sk), info->userhdr, info->attrs);
        if (IS_ERR(dp)) {
                err = PTR_ERR(dp);
                goto err_unlock_free;
        }
        err = ovs_dp_cmd_fill_info(dp, reply, info->snd_portid,
                                   info->snd_seq, 0, OVS_DP_CMD_GET);
        BUG_ON(err < 0);
        ovs_unlock();

        return genlmsg_reply(reply, info);

err_unlock_free:
        ovs_unlock();
        kfree_skb(reply);
        return err;
}

static int ovs_dp_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct ovs_net *ovs_net = net_generic(sock_net(skb->sk), ovs_net_id);
        struct datapath *dp;
        int skip = cb->args[0];
        int i = 0;

        ovs_lock();
        list_for_each_entry(dp, &ovs_net->dps, list_node) {
                if (i >= skip &&
                    ovs_dp_cmd_fill_info(dp, skb, NETLINK_CB(cb->skb).portid,
                                         cb->nlh->nlmsg_seq, NLM_F_MULTI,
                                         OVS_DP_CMD_GET) < 0)
                        break;
                i++;
        }
        ovs_unlock();

        cb->args[0] = i;

        return skb->len;
}

static const struct nla_policy datapath_policy[OVS_DP_ATTR_MAX + 1] = {
        [OVS_DP_ATTR_NAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 },
        [OVS_DP_ATTR_UPCALL_PID] = { .type = NLA_U32 },
        [OVS_DP_ATTR_USER_FEATURES] = { .type = NLA_U32 },
        [OVS_DP_ATTR_MASKS_CACHE_SIZE] =  NLA_POLICY_RANGE(NLA_U32, 0,
                PCPU_MIN_UNIT_SIZE / sizeof(struct mask_cache_entry)),
};

static const struct genl_small_ops dp_datapath_genl_ops[] = {
        { .cmd = OVS_DP_CMD_NEW,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */

          .doit = ovs_dp_cmd_new
        },
        { .cmd = OVS_DP_CMD_DEL,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_dp_cmd_del
        },
        { .cmd = OVS_DP_CMD_GET,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = 0,               /* OK for unprivileged users. */
          .doit = ovs_dp_cmd_get,
          .dumpit = ovs_dp_cmd_dump
        },
        { .cmd = OVS_DP_CMD_SET,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_dp_cmd_set,
        },
};

static struct genl_family dp_datapath_genl_family __ro_after_init = {
        .hdrsize = sizeof(struct ovs_header),
        .name = OVS_DATAPATH_FAMILY,
        .version = OVS_DATAPATH_VERSION,
        .maxattr = OVS_DP_ATTR_MAX,
        .policy = datapath_policy,
        .netnsok = true,
        .parallel_ops = true,
        .small_ops = dp_datapath_genl_ops,
        .n_small_ops = ARRAY_SIZE(dp_datapath_genl_ops),
        .mcgrps = &ovs_dp_datapath_multicast_group,
        .n_mcgrps = 1,
        .module = THIS_MODULE,
};

/* Called with ovs_mutex or RCU read lock. */
static int ovs_vport_cmd_fill_info(struct vport *vport, struct sk_buff *skb,
                                   struct net *net, u32 portid, u32 seq,
                                   u32 flags, u8 cmd, gfp_t gfp)
{
        struct ovs_header *ovs_header;
        struct ovs_vport_stats vport_stats;
        int err;

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

        ovs_header->dp_ifindex = get_dpifindex(vport->dp);

        if (nla_put_u32(skb, OVS_VPORT_ATTR_PORT_NO, vport->port_no) ||
            nla_put_u32(skb, OVS_VPORT_ATTR_TYPE, vport->ops->type) ||
            nla_put_string(skb, OVS_VPORT_ATTR_NAME,
                           ovs_vport_name(vport)) ||
            nla_put_u32(skb, OVS_VPORT_ATTR_IFINDEX, vport->dev->ifindex))
                goto nla_put_failure;

        if (!net_eq(net, dev_net(vport->dev))) {
                int id = peernet2id_alloc(net, dev_net(vport->dev), gfp);

                if (nla_put_s32(skb, OVS_VPORT_ATTR_NETNSID, id))
                        goto nla_put_failure;
        }

        ovs_vport_get_stats(vport, &vport_stats);
        if (nla_put_64bit(skb, OVS_VPORT_ATTR_STATS,
                          sizeof(struct ovs_vport_stats), &vport_stats,
                          OVS_VPORT_ATTR_PAD))
                goto nla_put_failure;

        if (ovs_vport_get_upcall_portids(vport, skb))
                goto nla_put_failure;

        err = ovs_vport_get_options(vport, skb);
        if (err == -EMSGSIZE)
                goto error;

        genlmsg_end(skb, ovs_header);
        return 0;

nla_put_failure:
        err = -EMSGSIZE;
error:
        genlmsg_cancel(skb, ovs_header);
        return err;
}

static struct sk_buff *ovs_vport_cmd_alloc_info(void)
{
        return nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
}

/* Called with ovs_mutex, only via ovs_dp_notify_wq(). */
struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, struct net *net,
                                         u32 portid, u32 seq, u8 cmd)
{
        struct sk_buff *skb;
        int retval;

        skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
        if (!skb)
                return ERR_PTR(-ENOMEM);

        retval = ovs_vport_cmd_fill_info(vport, skb, net, portid, seq, 0, cmd,
                                         GFP_KERNEL);
        BUG_ON(retval < 0);

        return skb;
}

/* Called with ovs_mutex or RCU read lock. */
static struct vport *lookup_vport(struct net *net,
                                  const struct ovs_header *ovs_header,
                                  struct nlattr *a[OVS_VPORT_ATTR_MAX + 1])
{
        struct datapath *dp;
        struct vport *vport;

        if (a[OVS_VPORT_ATTR_IFINDEX])
                return ERR_PTR(-EOPNOTSUPP);
        if (a[OVS_VPORT_ATTR_NAME]) {
                vport = ovs_vport_locate(net, nla_data(a[OVS_VPORT_ATTR_NAME]));
                if (!vport)
                        return ERR_PTR(-ENODEV);
                if (ovs_header->dp_ifindex &&
                    ovs_header->dp_ifindex != get_dpifindex(vport->dp))
                        return ERR_PTR(-ENODEV);
                return vport;
        } else if (a[OVS_VPORT_ATTR_PORT_NO]) {
                u32 port_no = nla_get_u32(a[OVS_VPORT_ATTR_PORT_NO]);

                if (port_no >= DP_MAX_PORTS)
                        return ERR_PTR(-EFBIG);

                dp = get_dp(net, ovs_header->dp_ifindex);
                if (!dp)
                        return ERR_PTR(-ENODEV);

                vport = ovs_vport_ovsl_rcu(dp, port_no);
                if (!vport)
                        return ERR_PTR(-ENODEV);
                return vport;
        } else
                return ERR_PTR(-EINVAL);

}

static unsigned int ovs_get_max_headroom(struct datapath *dp)
{
        unsigned int dev_headroom, max_headroom = 0;
        struct net_device *dev;
        struct vport *vport;
        int i;

        for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++) {
                hlist_for_each_entry_rcu(vport, &dp->ports[i], dp_hash_node,
                                         lockdep_ovsl_is_held()) {
                        dev = vport->dev;
                        dev_headroom = netdev_get_fwd_headroom(dev);
                        if (dev_headroom > max_headroom)
                                max_headroom = dev_headroom;
                }
        }

        return max_headroom;
}

/* Called with ovs_mutex */
static void ovs_update_headroom(struct datapath *dp, unsigned int new_headroom)
{
        struct vport *vport;
        int i;

        dp->max_headroom = new_headroom;
        for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++) {
                hlist_for_each_entry_rcu(vport, &dp->ports[i], dp_hash_node,
                                         lockdep_ovsl_is_held())
                        netdev_set_rx_headroom(vport->dev, new_headroom);
        }
}

static int ovs_vport_cmd_new(struct sk_buff *skb, struct genl_info *info)
{
        struct nlattr **a = info->attrs;
        struct ovs_header *ovs_header = info->userhdr;
        struct vport_parms parms;
        struct sk_buff *reply;
        struct vport *vport;
        struct datapath *dp;
        unsigned int new_headroom;
        u32 port_no;
        int err;

        if (!a[OVS_VPORT_ATTR_NAME] || !a[OVS_VPORT_ATTR_TYPE] ||
            !a[OVS_VPORT_ATTR_UPCALL_PID])
                return -EINVAL;
        if (a[OVS_VPORT_ATTR_IFINDEX])
                return -EOPNOTSUPP;

        port_no = a[OVS_VPORT_ATTR_PORT_NO]
                ? nla_get_u32(a[OVS_VPORT_ATTR_PORT_NO]) : 0;
        if (port_no >= DP_MAX_PORTS)
                return -EFBIG;

        reply = ovs_vport_cmd_alloc_info();
        if (!reply)
                return -ENOMEM;

        ovs_lock();
restart:
        dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
        err = -ENODEV;
        if (!dp)
                goto exit_unlock_free;

        if (port_no) {
                vport = ovs_vport_ovsl(dp, port_no);
                err = -EBUSY;
                if (vport)
                        goto exit_unlock_free;
        } else {
                for (port_no = 1; ; port_no++) {
                        if (port_no >= DP_MAX_PORTS) {
                                err = -EFBIG;
                                goto exit_unlock_free;
                        }
                        vport = ovs_vport_ovsl(dp, port_no);
                        if (!vport)
                                break;
                }
        }

        parms.name = nla_data(a[OVS_VPORT_ATTR_NAME]);
        parms.type = nla_get_u32(a[OVS_VPORT_ATTR_TYPE]);
        parms.options = a[OVS_VPORT_ATTR_OPTIONS];
        parms.dp = dp;
        parms.port_no = port_no;
        parms.upcall_portids = a[OVS_VPORT_ATTR_UPCALL_PID];

        vport = new_vport(&parms);
        err = PTR_ERR(vport);
        if (IS_ERR(vport)) {
                if (err == -EAGAIN)
                        goto restart;
                goto exit_unlock_free;
        }

        err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
                                      info->snd_portid, info->snd_seq, 0,
                                      OVS_VPORT_CMD_NEW, GFP_KERNEL);

        new_headroom = netdev_get_fwd_headroom(vport->dev);

        if (new_headroom > dp->max_headroom)
                ovs_update_headroom(dp, new_headroom);
        else
                netdev_set_rx_headroom(vport->dev, dp->max_headroom);

        BUG_ON(err < 0);
        ovs_unlock();

        ovs_notify(&dp_vport_genl_family, reply, info);
        return 0;

exit_unlock_free:
        ovs_unlock();
        kfree_skb(reply);
        return err;
}

static int ovs_vport_cmd_set(struct sk_buff *skb, struct genl_info *info)
{
        struct nlattr **a = info->attrs;
        struct sk_buff *reply;
        struct vport *vport;
        int err;

        reply = ovs_vport_cmd_alloc_info();
        if (!reply)
                return -ENOMEM;

        ovs_lock();
        vport = lookup_vport(sock_net(skb->sk), info->userhdr, a);
        err = PTR_ERR(vport);
        if (IS_ERR(vport))
                goto exit_unlock_free;

        if (a[OVS_VPORT_ATTR_TYPE] &&
            nla_get_u32(a[OVS_VPORT_ATTR_TYPE]) != vport->ops->type) {
                err = -EINVAL;
                goto exit_unlock_free;
        }

        if (a[OVS_VPORT_ATTR_OPTIONS]) {
                err = ovs_vport_set_options(vport, a[OVS_VPORT_ATTR_OPTIONS]);
                if (err)
                        goto exit_unlock_free;
        }


        if (a[OVS_VPORT_ATTR_UPCALL_PID]) {
                struct nlattr *ids = a[OVS_VPORT_ATTR_UPCALL_PID];

                err = ovs_vport_set_upcall_portids(vport, ids);
                if (err)
                        goto exit_unlock_free;
        }

        err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
                                      info->snd_portid, info->snd_seq, 0,
                                      OVS_VPORT_CMD_SET, GFP_KERNEL);
        BUG_ON(err < 0);

        ovs_unlock();
        ovs_notify(&dp_vport_genl_family, reply, info);
        return 0;

exit_unlock_free:
        ovs_unlock();
        kfree_skb(reply);
        return err;
}

static int ovs_vport_cmd_del(struct sk_buff *skb, struct genl_info *info)
{
        bool update_headroom = false;
        struct nlattr **a = info->attrs;
        struct sk_buff *reply;
        struct datapath *dp;
        struct vport *vport;
        unsigned int new_headroom;
        int err;

        reply = ovs_vport_cmd_alloc_info();
        if (!reply)
                return -ENOMEM;

        ovs_lock();
        vport = lookup_vport(sock_net(skb->sk), info->userhdr, a);
        err = PTR_ERR(vport);
        if (IS_ERR(vport))
                goto exit_unlock_free;

        if (vport->port_no == OVSP_LOCAL) {
                err = -EINVAL;
                goto exit_unlock_free;
        }

        err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
                                      info->snd_portid, info->snd_seq, 0,
                                      OVS_VPORT_CMD_DEL, GFP_KERNEL);
        BUG_ON(err < 0);

        /* the vport deletion may trigger dp headroom update */
        dp = vport->dp;
        if (netdev_get_fwd_headroom(vport->dev) == dp->max_headroom)
                update_headroom = true;

        netdev_reset_rx_headroom(vport->dev);
        ovs_dp_detach_port(vport);

        if (update_headroom) {
                new_headroom = ovs_get_max_headroom(dp);

                if (new_headroom < dp->max_headroom)
                        ovs_update_headroom(dp, new_headroom);
        }
        ovs_unlock();

        ovs_notify(&dp_vport_genl_family, reply, info);
        return 0;

exit_unlock_free:
        ovs_unlock();
        kfree_skb(reply);
        return err;
}

static int ovs_vport_cmd_get(struct sk_buff *skb, struct genl_info *info)
{
        struct nlattr **a = info->attrs;
        struct ovs_header *ovs_header = info->userhdr;
        struct sk_buff *reply;
        struct vport *vport;
        int err;

        reply = ovs_vport_cmd_alloc_info();
        if (!reply)
                return -ENOMEM;

        rcu_read_lock();
        vport = lookup_vport(sock_net(skb->sk), ovs_header, a);
        err = PTR_ERR(vport);
        if (IS_ERR(vport))
                goto exit_unlock_free;
        err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
                                      info->snd_portid, info->snd_seq, 0,
                                      OVS_VPORT_CMD_GET, GFP_ATOMIC);
        BUG_ON(err < 0);
        rcu_read_unlock();

        return genlmsg_reply(reply, info);

exit_unlock_free:
        rcu_read_unlock();
        kfree_skb(reply);
        return err;
}

static int ovs_vport_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct ovs_header *ovs_header = genlmsg_data(nlmsg_data(cb->nlh));
        struct datapath *dp;
        int bucket = cb->args[0], skip = cb->args[1];
        int i, j = 0;

        rcu_read_lock();
        dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex);
        if (!dp) {
                rcu_read_unlock();
                return -ENODEV;
        }
        for (i = bucket; i < DP_VPORT_HASH_BUCKETS; i++) {
                struct vport *vport;

                j = 0;
                hlist_for_each_entry_rcu(vport, &dp->ports[i], dp_hash_node) {
                        if (j >= skip &&
                            ovs_vport_cmd_fill_info(vport, skb,
                                                    sock_net(skb->sk),
                                                    NETLINK_CB(cb->skb).portid,
                                                    cb->nlh->nlmsg_seq,
                                                    NLM_F_MULTI,
                                                    OVS_VPORT_CMD_GET,
                                                    GFP_ATOMIC) < 0)
                                goto out;

                        j++;
                }
                skip = 0;
        }
out:
        rcu_read_unlock();

        cb->args[0] = i;
        cb->args[1] = j;

        return skb->len;
}

static void ovs_dp_masks_rebalance(struct work_struct *work)
{
        struct ovs_net *ovs_net = container_of(work, struct ovs_net,
                                               masks_rebalance.work);
        struct datapath *dp;

        ovs_lock();

        list_for_each_entry(dp, &ovs_net->dps, list_node)
                ovs_flow_masks_rebalance(&dp->table);

        ovs_unlock();

        schedule_delayed_work(&ovs_net->masks_rebalance,
                              msecs_to_jiffies(DP_MASKS_REBALANCE_INTERVAL));
}

static const struct nla_policy vport_policy[OVS_VPORT_ATTR_MAX + 1] = {
        [OVS_VPORT_ATTR_NAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 },
        [OVS_VPORT_ATTR_STATS] = { .len = sizeof(struct ovs_vport_stats) },
        [OVS_VPORT_ATTR_PORT_NO] = { .type = NLA_U32 },
        [OVS_VPORT_ATTR_TYPE] = { .type = NLA_U32 },
        [OVS_VPORT_ATTR_UPCALL_PID] = { .type = NLA_UNSPEC },
        [OVS_VPORT_ATTR_OPTIONS] = { .type = NLA_NESTED },
        [OVS_VPORT_ATTR_IFINDEX] = { .type = NLA_U32 },
        [OVS_VPORT_ATTR_NETNSID] = { .type = NLA_S32 },
};

static const struct genl_small_ops dp_vport_genl_ops[] = {
        { .cmd = OVS_VPORT_CMD_NEW,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_vport_cmd_new
        },
        { .cmd = OVS_VPORT_CMD_DEL,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_vport_cmd_del
        },
        { .cmd = OVS_VPORT_CMD_GET,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = 0,               /* OK for unprivileged users. */
          .doit = ovs_vport_cmd_get,
          .dumpit = ovs_vport_cmd_dump
        },
        { .cmd = OVS_VPORT_CMD_SET,
          .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
          .flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
          .doit = ovs_vport_cmd_set,
        },
};

struct genl_family dp_vport_genl_family __ro_after_init = {
        .hdrsize = sizeof(struct ovs_header),
        .name = OVS_VPORT_FAMILY,
        .version = OVS_VPORT_VERSION,
        .maxattr = OVS_VPORT_ATTR_MAX,
        .policy = vport_policy,
        .netnsok = true,
        .parallel_ops = true,
        .small_ops = dp_vport_genl_ops,
        .n_small_ops = ARRAY_SIZE(dp_vport_genl_ops),
        .mcgrps = &ovs_dp_vport_multicast_group,
        .n_mcgrps = 1,
        .module = THIS_MODULE,
};

static struct genl_family * const dp_genl_families[] = {
        &dp_datapath_genl_family,
        &dp_vport_genl_family,
        &dp_flow_genl_family,
        &dp_packet_genl_family,
        &dp_meter_genl_family,
#if     IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
        &dp_ct_limit_genl_family,
#endif
};

static void dp_unregister_genl(int n_families)
{
        int i;

        for (i = 0; i < n_families; i++)
                genl_unregister_family(dp_genl_families[i]);
}

static int __init dp_register_genl(void)
{
        int err;
        int i;

        for (i = 0; i < ARRAY_SIZE(dp_genl_families); i++) {

                err = genl_register_family(dp_genl_families[i]);
                if (err)
                        goto error;
        }

        return 0;

error:
        dp_unregister_genl(i);
        return err;
}

static int __net_init ovs_init_net(struct net *net)
{
        struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
        int err;

        INIT_LIST_HEAD(&ovs_net->dps);
        INIT_WORK(&ovs_net->dp_notify_work, ovs_dp_notify_wq);
        INIT_DELAYED_WORK(&ovs_net->masks_rebalance, ovs_dp_masks_rebalance);

        err = ovs_ct_init(net);
        if (err)
                return err;

        schedule_delayed_work(&ovs_net->masks_rebalance,
                              msecs_to_jiffies(DP_MASKS_REBALANCE_INTERVAL));
        return 0;
}

static void __net_exit list_vports_from_net(struct net *net, struct net *dnet,
                                            struct list_head *head)
{
        struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
        struct datapath *dp;

        list_for_each_entry(dp, &ovs_net->dps, list_node) {
                int i;

                for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++) {
                        struct vport *vport;

                        hlist_for_each_entry(vport, &dp->ports[i], dp_hash_node) {
                                if (vport->ops->type != OVS_VPORT_TYPE_INTERNAL)
                                        continue;

                                if (dev_net(vport->dev) == dnet)
                                        list_add(&vport->detach_list, head);
                        }
                }
        }
}

static void __net_exit ovs_exit_net(struct net *dnet)
{
        struct datapath *dp, *dp_next;
        struct ovs_net *ovs_net = net_generic(dnet, ovs_net_id);
        struct vport *vport, *vport_next;
        struct net *net;
        LIST_HEAD(head);

        ovs_lock();

        ovs_ct_exit(dnet);

        list_for_each_entry_safe(dp, dp_next, &ovs_net->dps, list_node)
                __dp_destroy(dp);

        down_read(&net_rwsem);
        for_each_net(net)
                list_vports_from_net(net, dnet, &head);
        up_read(&net_rwsem);

        /* Detach all vports from given namespace. */
        list_for_each_entry_safe(vport, vport_next, &head, detach_list) {
                list_del(&vport->detach_list);
                ovs_dp_detach_port(vport);
        }

        ovs_unlock();

        cancel_delayed_work_sync(&ovs_net->masks_rebalance);
        cancel_work_sync(&ovs_net->dp_notify_work);
}

static struct pernet_operations ovs_net_ops = {
        .init = ovs_init_net,
        .exit = ovs_exit_net,
        .id   = &ovs_net_id,
        .size = sizeof(struct ovs_net),
};

static int __init dp_init(void)
{
        int err;

        BUILD_BUG_ON(sizeof(struct ovs_skb_cb) >
                     sizeof_field(struct sk_buff, cb));

        pr_info("Open vSwitch switching datapath\n");

        err = action_fifos_init();
        if (err)
                goto error;

        err = ovs_internal_dev_rtnl_link_register();
        if (err)
                goto error_action_fifos_exit;

        err = ovs_flow_init();
        if (err)
                goto error_unreg_rtnl_link;

        err = ovs_vport_init();
        if (err)
                goto error_flow_exit;

        err = register_pernet_device(&ovs_net_ops);
        if (err)
                goto error_vport_exit;

        err = register_netdevice_notifier(&ovs_dp_device_notifier);
        if (err)
                goto error_netns_exit;

        err = ovs_netdev_init();
        if (err)
                goto error_unreg_notifier;

        err = dp_register_genl();
        if (err < 0)
                goto error_unreg_netdev;

        return 0;

error_unreg_netdev:
        ovs_netdev_exit();
error_unreg_notifier:
        unregister_netdevice_notifier(&ovs_dp_device_notifier);
error_netns_exit:
        unregister_pernet_device(&ovs_net_ops);
error_vport_exit:
        ovs_vport_exit();
error_flow_exit:
        ovs_flow_exit();
error_unreg_rtnl_link:
        ovs_internal_dev_rtnl_link_unregister();
error_action_fifos_exit:
        action_fifos_exit();
error:
        return err;
}

static void dp_cleanup(void)
{
        dp_unregister_genl(ARRAY_SIZE(dp_genl_families));
        ovs_netdev_exit();
        unregister_netdevice_notifier(&ovs_dp_device_notifier);
        unregister_pernet_device(&ovs_net_ops);
        rcu_barrier();
        ovs_vport_exit();
        ovs_flow_exit();
        ovs_internal_dev_rtnl_link_unregister();
        action_fifos_exit();
}

module_init(dp_init);
module_exit(dp_cleanup);

MODULE_DESCRIPTION("Open vSwitch switching datapath");
MODULE_LICENSE("GPL");
MODULE_ALIAS_GENL_FAMILY(OVS_DATAPATH_FAMILY);
MODULE_ALIAS_GENL_FAMILY(OVS_VPORT_FAMILY);
MODULE_ALIAS_GENL_FAMILY(OVS_FLOW_FAMILY);
MODULE_ALIAS_GENL_FAMILY(OVS_PACKET_FAMILY);
MODULE_ALIAS_GENL_FAMILY(OVS_METER_FAMILY);
MODULE_ALIAS_GENL_FAMILY(OVS_CT_LIMIT_FAMILY);