/*
 * Copyright (c) 2007-2013 Nicira, Inc.
 *
 * 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
 */

#include "flow.h"
#include "datapath.h"
#include <linux/uaccess.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <net/llc_pdu.h>
#include <linux/kernel.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/llc.h>
#include <linux/module.h>
#include <linux/in.h>
#include <linux/rcupdate.h>
#include <linux/if_arp.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/sctp.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/icmp.h>
#include <linux/icmpv6.h>
#include <linux/rculist.h>
#include <net/ip.h>
#include <net/ip_tunnels.h>
#include <net/ipv6.h>
#include <net/ndisc.h>

static struct kmem_cache *flow_cache;

static void ovs_sw_flow_mask_set(struct sw_flow_mask *mask,
                struct sw_flow_key_range *range, u8 val);

static void update_range__(struct sw_flow_match *match,
                          size_t offset, size_t size, bool is_mask)
{
        struct sw_flow_key_range *range = NULL;
        size_t start = rounddown(offset, sizeof(long));
        size_t end = roundup(offset + size, sizeof(long));

        if (!is_mask)
                range = &match->range;
        else if (match->mask)
                range = &match->mask->range;

        if (!range)
                return;

        if (range->start == range->end) {
                range->start = start;
                range->end = end;
                return;
        }

        if (range->start > start)
                range->start = start;

        if (range->end < end)
                range->end = end;
}

#define SW_FLOW_KEY_PUT(match, field, value, is_mask) \
        do { \
                update_range__(match, offsetof(struct sw_flow_key, field),  \
                                     sizeof((match)->key->field), is_mask); \
                if (is_mask) {                                              \
                        if ((match)->mask)                                  \
                                (match)->mask->key.field = value;           \
                } else {                                                    \
                        (match)->key->field = value;                        \
                }                                                           \
        } while (0)

#define SW_FLOW_KEY_MEMCPY(match, field, value_p, len, is_mask) \
        do { \
                update_range__(match, offsetof(struct sw_flow_key, field),  \
                                len, is_mask);                              \
                if (is_mask) {                                              \
                        if ((match)->mask)                                  \
                                memcpy(&(match)->mask->key.field, value_p, len);\
                } else {                                                    \
                        memcpy(&(match)->key->field, value_p, len);         \
                }                                                           \
        } while (0)

static u16 range_n_bytes(const struct sw_flow_key_range *range)
{
        return range->end - range->start;
}

void ovs_match_init(struct sw_flow_match *match,
                    struct sw_flow_key *key,
                    struct sw_flow_mask *mask)
{
        memset(match, 0, sizeof(*match));
        match->key = key;
        match->mask = mask;

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

        if (mask) {
                memset(&mask->key, 0, sizeof(mask->key));
                mask->range.start = mask->range.end = 0;
        }
}

static bool ovs_match_validate(const struct sw_flow_match *match,
                u64 key_attrs, u64 mask_attrs)
{
        u64 key_expected = 1 << OVS_KEY_ATTR_ETHERNET;
        u64 mask_allowed = key_attrs;  /* At most allow all key attributes */

        /* The following mask attributes allowed only if they
         * pass the validation tests. */
        mask_allowed &= ~((1 << OVS_KEY_ATTR_IPV4)
                        | (1 << OVS_KEY_ATTR_IPV6)
                        | (1 << OVS_KEY_ATTR_TCP)
                        | (1 << OVS_KEY_ATTR_UDP)
                        | (1 << OVS_KEY_ATTR_SCTP)
                        | (1 << OVS_KEY_ATTR_ICMP)
                        | (1 << OVS_KEY_ATTR_ICMPV6)
                        | (1 << OVS_KEY_ATTR_ARP)
                        | (1 << OVS_KEY_ATTR_ND));

        /* Always allowed mask fields. */
        mask_allowed |= ((1 << OVS_KEY_ATTR_TUNNEL)
                       | (1 << OVS_KEY_ATTR_IN_PORT)
                       | (1 << OVS_KEY_ATTR_ETHERTYPE));

        /* Check key attributes. */
        if (match->key->eth.type == htons(ETH_P_ARP)
                        || match->key->eth.type == htons(ETH_P_RARP)) {
                key_expected |= 1 << OVS_KEY_ATTR_ARP;
                if (match->mask && (match->mask->key.eth.type == htons(0xffff)))
                        mask_allowed |= 1 << OVS_KEY_ATTR_ARP;
        }

        if (match->key->eth.type == htons(ETH_P_IP)) {
                key_expected |= 1 << OVS_KEY_ATTR_IPV4;
                if (match->mask && (match->mask->key.eth.type == htons(0xffff)))
                        mask_allowed |= 1 << OVS_KEY_ATTR_IPV4;

                if (match->key->ip.frag != OVS_FRAG_TYPE_LATER) {
                        if (match->key->ip.proto == IPPROTO_UDP) {
                                key_expected |= 1 << OVS_KEY_ATTR_UDP;
                                if (match->mask && (match->mask->key.ip.proto == 0xff))
                                        mask_allowed |= 1 << OVS_KEY_ATTR_UDP;
                        }

                        if (match->key->ip.proto == IPPROTO_SCTP) {
                                key_expected |= 1 << OVS_KEY_ATTR_SCTP;
                                if (match->mask && (match->mask->key.ip.proto == 0xff))
                                        mask_allowed |= 1 << OVS_KEY_ATTR_SCTP;
                        }

                        if (match->key->ip.proto == IPPROTO_TCP) {
                                key_expected |= 1 << OVS_KEY_ATTR_TCP;
                                if (match->mask && (match->mask->key.ip.proto == 0xff))
                                        mask_allowed |= 1 << OVS_KEY_ATTR_TCP;
                        }

                        if (match->key->ip.proto == IPPROTO_ICMP) {
                                key_expected |= 1 << OVS_KEY_ATTR_ICMP;
                                if (match->mask && (match->mask->key.ip.proto == 0xff))
                                        mask_allowed |= 1 << OVS_KEY_ATTR_ICMP;
                        }
                }
        }

        if (match->key->eth.type == htons(ETH_P_IPV6)) {
                key_expected |= 1 << OVS_KEY_ATTR_IPV6;
                if (match->mask && (match->mask->key.eth.type == htons(0xffff)))
                        mask_allowed |= 1 << OVS_KEY_ATTR_IPV6;

                if (match->key->ip.frag != OVS_FRAG_TYPE_LATER) {
                        if (match->key->ip.proto == IPPROTO_UDP) {
                                key_expected |= 1 << OVS_KEY_ATTR_UDP;
                                if (match->mask && (match->mask->key.ip.proto == 0xff))
                                        mask_allowed |= 1 << OVS_KEY_ATTR_UDP;
                        }

                        if (match->key->ip.proto == IPPROTO_SCTP) {
                                key_expected |= 1 << OVS_KEY_ATTR_SCTP;
                                if (match->mask && (match->mask->key.ip.proto == 0xff))
                                        mask_allowed |= 1 << OVS_KEY_ATTR_SCTP;
                        }

                        if (match->key->ip.proto == IPPROTO_TCP) {
                                key_expected |= 1 << OVS_KEY_ATTR_TCP;
                                if (match->mask && (match->mask->key.ip.proto == 0xff))
                                        mask_allowed |= 1 << OVS_KEY_ATTR_TCP;
                        }

                        if (match->key->ip.proto == IPPROTO_ICMPV6) {
                                key_expected |= 1 << OVS_KEY_ATTR_ICMPV6;
                                if (match->mask && (match->mask->key.ip.proto == 0xff))
                                        mask_allowed |= 1 << OVS_KEY_ATTR_ICMPV6;

                                if (match->key->ipv6.tp.src ==
                                                htons(NDISC_NEIGHBOUR_SOLICITATION) ||
                                    match->key->ipv6.tp.src == htons(NDISC_NEIGHBOUR_ADVERTISEMENT)) {
                                        key_expected |= 1 << OVS_KEY_ATTR_ND;
                                        if (match->mask && (match->mask->key.ipv6.tp.src == htons(0xffff)))
                                                mask_allowed |= 1 << OVS_KEY_ATTR_ND;
                                }
                        }
                }
        }

        if ((key_attrs & key_expected) != key_expected) {
                /* Key attributes check failed. */
                OVS_NLERR("Missing expected key attributes (key_attrs=%llx, expected=%llx).\n",
                                key_attrs, key_expected);
                return false;
        }

        if ((mask_attrs & mask_allowed) != mask_attrs) {
                /* Mask attributes check failed. */
                OVS_NLERR("Contain more than allowed mask fields (mask_attrs=%llx, mask_allowed=%llx).\n",
                                mask_attrs, mask_allowed);
                return false;
        }

        return true;
}

static int check_header(struct sk_buff *skb, int len)
{
        if (unlikely(skb->len < len))
                return -EINVAL;
        if (unlikely(!pskb_may_pull(skb, len)))
                return -ENOMEM;
        return 0;
}

static bool arphdr_ok(struct sk_buff *skb)
{
        return pskb_may_pull(skb, skb_network_offset(skb) +
                                  sizeof(struct arp_eth_header));
}

static int check_iphdr(struct sk_buff *skb)
{
        unsigned int nh_ofs = skb_network_offset(skb);
        unsigned int ip_len;
        int err;

        err = check_header(skb, nh_ofs + sizeof(struct iphdr));
        if (unlikely(err))
                return err;

        ip_len = ip_hdrlen(skb);
        if (unlikely(ip_len < sizeof(struct iphdr) ||
                     skb->len < nh_ofs + ip_len))
                return -EINVAL;

        skb_set_transport_header(skb, nh_ofs + ip_len);
        return 0;
}

static bool tcphdr_ok(struct sk_buff *skb)
{
        int th_ofs = skb_transport_offset(skb);
        int tcp_len;

        if (unlikely(!pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))))
                return false;

        tcp_len = tcp_hdrlen(skb);
        if (unlikely(tcp_len < sizeof(struct tcphdr) ||
                     skb->len < th_ofs + tcp_len))
                return false;

        return true;
}

static bool udphdr_ok(struct sk_buff *skb)
{
        return pskb_may_pull(skb, skb_transport_offset(skb) +
                                  sizeof(struct udphdr));
}

static bool sctphdr_ok(struct sk_buff *skb)
{
        return pskb_may_pull(skb, skb_transport_offset(skb) +
                                  sizeof(struct sctphdr));
}

static bool icmphdr_ok(struct sk_buff *skb)
{
        return pskb_may_pull(skb, skb_transport_offset(skb) +
                                  sizeof(struct icmphdr));
}

u64 ovs_flow_used_time(unsigned long flow_jiffies)
{
        struct timespec cur_ts;
        u64 cur_ms, idle_ms;

        ktime_get_ts(&cur_ts);
        idle_ms = jiffies_to_msecs(jiffies - flow_jiffies);
        cur_ms = (u64)cur_ts.tv_sec * MSEC_PER_SEC +
                 cur_ts.tv_nsec / NSEC_PER_MSEC;

        return cur_ms - idle_ms;
}

static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
{
        unsigned int nh_ofs = skb_network_offset(skb);
        unsigned int nh_len;
        int payload_ofs;
        struct ipv6hdr *nh;
        uint8_t nexthdr;
        __be16 frag_off;
        int err;

        err = check_header(skb, nh_ofs + sizeof(*nh));
        if (unlikely(err))
                return err;

        nh = ipv6_hdr(skb);
        nexthdr = nh->nexthdr;
        payload_ofs = (u8 *)(nh + 1) - skb->data;

        key->ip.proto = NEXTHDR_NONE;
        key->ip.tos = ipv6_get_dsfield(nh);
        key->ip.ttl = nh->hop_limit;
        key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
        key->ipv6.addr.src = nh->saddr;
        key->ipv6.addr.dst = nh->daddr;

        payload_ofs = ipv6_skip_exthdr(skb, payload_ofs, &nexthdr, &frag_off);
        if (unlikely(payload_ofs < 0))
                return -EINVAL;

        if (frag_off) {
                if (frag_off & htons(~0x7))
                        key->ip.frag = OVS_FRAG_TYPE_LATER;
                else
                        key->ip.frag = OVS_FRAG_TYPE_FIRST;
        }

        nh_len = payload_ofs - nh_ofs;
        skb_set_transport_header(skb, nh_ofs + nh_len);
        key->ip.proto = nexthdr;
        return nh_len;
}

static bool icmp6hdr_ok(struct sk_buff *skb)
{
        return pskb_may_pull(skb, skb_transport_offset(skb) +
                                  sizeof(struct icmp6hdr));
}

void ovs_flow_key_mask(struct sw_flow_key *dst, const struct sw_flow_key *src,
                       const struct sw_flow_mask *mask)
{
        const long *m = (long *)((u8 *)&mask->key + mask->range.start);
        const long *s = (long *)((u8 *)src + mask->range.start);
        long *d = (long *)((u8 *)dst + mask->range.start);
        int i;

        /* The memory outside of the 'mask->range' are not set since
         * further operations on 'dst' only uses contents within
         * 'mask->range'.
         */
        for (i = 0; i < range_n_bytes(&mask->range); i += sizeof(long))
                *d++ = *s++ & *m++;
}

#define TCP_FLAGS_OFFSET 13
#define TCP_FLAG_MASK 0x3f

void ovs_flow_used(struct sw_flow *flow, struct sk_buff *skb)
{
        u8 tcp_flags = 0;

        if ((flow->key.eth.type == htons(ETH_P_IP) ||
             flow->key.eth.type == htons(ETH_P_IPV6)) &&
            flow->key.ip.proto == IPPROTO_TCP &&
            likely(skb->len >= skb_transport_offset(skb) + sizeof(struct tcphdr))) {
                u8 *tcp = (u8 *)tcp_hdr(skb);
                tcp_flags = *(tcp + TCP_FLAGS_OFFSET) & TCP_FLAG_MASK;
        }

        spin_lock(&flow->lock);
        flow->used = jiffies;
        flow->packet_count++;
        flow->byte_count += skb->len;
        flow->tcp_flags |= tcp_flags;
        spin_unlock(&flow->lock);
}

struct sw_flow_actions *ovs_flow_actions_alloc(int size)
{
        struct sw_flow_actions *sfa;

        if (size > MAX_ACTIONS_BUFSIZE)
                return ERR_PTR(-EINVAL);

        sfa = kmalloc(sizeof(*sfa) + size, GFP_KERNEL);
        if (!sfa)
                return ERR_PTR(-ENOMEM);

        sfa->actions_len = 0;
        return sfa;
}

struct sw_flow *ovs_flow_alloc(void)
{
        struct sw_flow *flow;

        flow = kmem_cache_alloc(flow_cache, GFP_KERNEL);
        if (!flow)
                return ERR_PTR(-ENOMEM);

        spin_lock_init(&flow->lock);
        flow->sf_acts = NULL;
        flow->mask = NULL;

        return flow;
}

static struct hlist_head *find_bucket(struct flow_table *table, u32 hash)
{
        hash = jhash_1word(hash, table->hash_seed);
        return flex_array_get(table->buckets,
                                (hash & (table->n_buckets - 1)));
}

static struct flex_array *alloc_buckets(unsigned int n_buckets)
{
        struct flex_array *buckets;
        int i, err;

        buckets = flex_array_alloc(sizeof(struct hlist_head),
                                   n_buckets, GFP_KERNEL);
        if (!buckets)
                return NULL;

        err = flex_array_prealloc(buckets, 0, n_buckets, GFP_KERNEL);
        if (err) {
                flex_array_free(buckets);
                return NULL;
        }

        for (i = 0; i < n_buckets; i++)
                INIT_HLIST_HEAD((struct hlist_head *)
                                        flex_array_get(buckets, i));

        return buckets;
}

static void free_buckets(struct flex_array *buckets)
{
        flex_array_free(buckets);
}

static struct flow_table *__flow_tbl_alloc(int new_size)
{
        struct flow_table *table = kmalloc(sizeof(*table), GFP_KERNEL);

        if (!table)
                return NULL;

        table->buckets = alloc_buckets(new_size);

        if (!table->buckets) {
                kfree(table);
                return NULL;
        }
        table->n_buckets = new_size;
        table->count = 0;
        table->node_ver = 0;
        table->keep_flows = false;
        get_random_bytes(&table->hash_seed, sizeof(u32));
        table->mask_list = NULL;

        return table;
}

static void __flow_tbl_destroy(struct flow_table *table)
{
        int i;

        if (table->keep_flows)
                goto skip_flows;

        for (i = 0; i < table->n_buckets; i++) {
                struct sw_flow *flow;
                struct hlist_head *head = flex_array_get(table->buckets, i);
                struct hlist_node *n;
                int ver = table->node_ver;

                hlist_for_each_entry_safe(flow, n, head, hash_node[ver]) {
                        hlist_del(&flow->hash_node[ver]);
                        ovs_flow_free(flow, false);
                }
        }

        BUG_ON(!list_empty(table->mask_list));
        kfree(table->mask_list);

skip_flows:
        free_buckets(table->buckets);
        kfree(table);
}

struct flow_table *ovs_flow_tbl_alloc(int new_size)
{
        struct flow_table *table = __flow_tbl_alloc(new_size);

        if (!table)
                return NULL;

        table->mask_list = kmalloc(sizeof(struct list_head), GFP_KERNEL);
        if (!table->mask_list) {
                table->keep_flows = true;
                __flow_tbl_destroy(table);
                return NULL;
        }
        INIT_LIST_HEAD(table->mask_list);

        return table;
}

static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
{
        struct flow_table *table = container_of(rcu, struct flow_table, rcu);

        __flow_tbl_destroy(table);
}

void ovs_flow_tbl_destroy(struct flow_table *table, bool deferred)
{
        if (!table)
                return;

        if (deferred)
                call_rcu(&table->rcu, flow_tbl_destroy_rcu_cb);
        else
                __flow_tbl_destroy(table);
}

struct sw_flow *ovs_flow_dump_next(struct flow_table *table, u32 *bucket, u32 *last)
{
        struct sw_flow *flow;
        struct hlist_head *head;
        int ver;
        int i;

        ver = table->node_ver;
        while (*bucket < table->n_buckets) {
                i = 0;
                head = flex_array_get(table->buckets, *bucket);
                hlist_for_each_entry_rcu(flow, head, hash_node[ver]) {
                        if (i < *last) {
                                i++;
                                continue;
                        }
                        *last = i + 1;
                        return flow;
                }
                (*bucket)++;
                *last = 0;
        }

        return NULL;
}

static void __tbl_insert(struct flow_table *table, struct sw_flow *flow)
{
        struct hlist_head *head;

        head = find_bucket(table, flow->hash);
        hlist_add_head_rcu(&flow->hash_node[table->node_ver], head);

        table->count++;
}

static void flow_table_copy_flows(struct flow_table *old, struct flow_table *new)
{
        int old_ver;
        int i;

        old_ver = old->node_ver;
        new->node_ver = !old_ver;

        /* Insert in new table. */
        for (i = 0; i < old->n_buckets; i++) {
                struct sw_flow *flow;
                struct hlist_head *head;

                head = flex_array_get(old->buckets, i);

                hlist_for_each_entry(flow, head, hash_node[old_ver])
                        __tbl_insert(new, flow);
        }

        new->mask_list = old->mask_list;
        old->keep_flows = true;
}

static struct flow_table *__flow_tbl_rehash(struct flow_table *table, int n_buckets)
{
        struct flow_table *new_table;

        new_table = __flow_tbl_alloc(n_buckets);
        if (!new_table)
                return ERR_PTR(-ENOMEM);

        flow_table_copy_flows(table, new_table);

        return new_table;
}

struct flow_table *ovs_flow_tbl_rehash(struct flow_table *table)
{
        return __flow_tbl_rehash(table, table->n_buckets);
}

struct flow_table *ovs_flow_tbl_expand(struct flow_table *table)
{
        return __flow_tbl_rehash(table, table->n_buckets * 2);
}

static void __flow_free(struct sw_flow *flow)
{
        kfree((struct sf_flow_acts __force *)flow->sf_acts);
        kmem_cache_free(flow_cache, flow);
}

static void rcu_free_flow_callback(struct rcu_head *rcu)
{
        struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);

        __flow_free(flow);
}

void ovs_flow_free(struct sw_flow *flow, bool deferred)
{
        if (!flow)
                return;

        ovs_sw_flow_mask_del_ref(flow->mask, deferred);

        if (deferred)
                call_rcu(&flow->rcu, rcu_free_flow_callback);
        else
                __flow_free(flow);
}

/* Schedules 'sf_acts' to be freed after the next RCU grace period.
 * The caller must hold rcu_read_lock for this to be sensible. */
void ovs_flow_deferred_free_acts(struct sw_flow_actions *sf_acts)
{
        kfree_rcu(sf_acts, rcu);
}

static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
{
        struct qtag_prefix {
                __be16 eth_type; /* ETH_P_8021Q */
                __be16 tci;
        };
        struct qtag_prefix *qp;

        if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
                return 0;

        if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
                                         sizeof(__be16))))
                return -ENOMEM;

        qp = (struct qtag_prefix *) skb->data;
        key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
        __skb_pull(skb, sizeof(struct qtag_prefix));

        return 0;
}

static __be16 parse_ethertype(struct sk_buff *skb)
{
        struct llc_snap_hdr {
                u8  dsap;  /* Always 0xAA */
                u8  ssap;  /* Always 0xAA */
                u8  ctrl;
                u8  oui[3];
                __be16 ethertype;
        };
        struct llc_snap_hdr *llc;
        __be16 proto;

        proto = *(__be16 *) skb->data;
        __skb_pull(skb, sizeof(__be16));

        if (ntohs(proto) >= ETH_P_802_3_MIN)
                return proto;

        if (skb->len < sizeof(struct llc_snap_hdr))
                return htons(ETH_P_802_2);

        if (unlikely(!pskb_may_pull(skb, sizeof(struct llc_snap_hdr))))
                return htons(0);

        llc = (struct llc_snap_hdr *) skb->data;
        if (llc->dsap != LLC_SAP_SNAP ||
            llc->ssap != LLC_SAP_SNAP ||
            (llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
                return htons(ETH_P_802_2);

        __skb_pull(skb, sizeof(struct llc_snap_hdr));

        if (ntohs(llc->ethertype) >= ETH_P_802_3_MIN)
                return llc->ethertype;

        return htons(ETH_P_802_2);
}

static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
                        int nh_len)
{
        struct icmp6hdr *icmp = icmp6_hdr(skb);

        /* The ICMPv6 type and code fields use the 16-bit transport port
         * fields, so we need to store them in 16-bit network byte order.
         */
        key->ipv6.tp.src = htons(icmp->icmp6_type);
        key->ipv6.tp.dst = htons(icmp->icmp6_code);

        if (icmp->icmp6_code == 0 &&
            (icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
             icmp->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
                int icmp_len = skb->len - skb_transport_offset(skb);
                struct nd_msg *nd;
                int offset;

                /* In order to process neighbor discovery options, we need the
                 * entire packet.
                 */
                if (unlikely(icmp_len < sizeof(*nd)))
                        return 0;

                if (unlikely(skb_linearize(skb)))
                        return -ENOMEM;

                nd = (struct nd_msg *)skb_transport_header(skb);
                key->ipv6.nd.target = nd->target;

                icmp_len -= sizeof(*nd);
                offset = 0;
                while (icmp_len >= 8) {
                        struct nd_opt_hdr *nd_opt =
                                 (struct nd_opt_hdr *)(nd->opt + offset);
                        int opt_len = nd_opt->nd_opt_len * 8;

                        if (unlikely(!opt_len || opt_len > icmp_len))
                                return 0;

                        /* Store the link layer address if the appropriate
                         * option is provided.  It is considered an error if
                         * the same link layer option is specified twice.
                         */
                        if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LL_ADDR
                            && opt_len == 8) {
                                if (unlikely(!is_zero_ether_addr(key->ipv6.nd.sll)))
                                        goto invalid;
                                memcpy(key->ipv6.nd.sll,
                                    &nd->opt[offset+sizeof(*nd_opt)], ETH_ALEN);
                        } else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LL_ADDR
                                   && opt_len == 8) {
                                if (unlikely(!is_zero_ether_addr(key->ipv6.nd.tll)))
                                        goto invalid;
                                memcpy(key->ipv6.nd.tll,
                                    &nd->opt[offset+sizeof(*nd_opt)], ETH_ALEN);
                        }

                        icmp_len -= opt_len;
                        offset += opt_len;
                }
        }

        return 0;

invalid:
        memset(&key->ipv6.nd.target, 0, sizeof(key->ipv6.nd.target));
        memset(key->ipv6.nd.sll, 0, sizeof(key->ipv6.nd.sll));
        memset(key->ipv6.nd.tll, 0, sizeof(key->ipv6.nd.tll));

        return 0;
}

/**
 * ovs_flow_extract - extracts a flow key from an Ethernet frame.
 * @skb: sk_buff that contains the frame, with skb->data pointing to the
 * Ethernet header
 * @in_port: port number on which @skb was received.
 * @key: output flow key
 *
 * The caller must ensure that skb->len >= ETH_HLEN.
 *
 * Returns 0 if successful, otherwise a negative errno value.
 *
 * Initializes @skb header pointers as follows:
 *
 *    - skb->mac_header: the Ethernet header.
 *
 *    - skb->network_header: just past the Ethernet header, or just past the
 *      VLAN header, to the first byte of the Ethernet payload.
 *
 *    - skb->transport_header: If key->eth.type is ETH_P_IP or ETH_P_IPV6
 *      on output, then just past the IP header, if one is present and
 *      of a correct length, otherwise the same as skb->network_header.
 *      For other key->eth.type values it is left untouched.
 */
int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
{
        int error;
        struct ethhdr *eth;

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

        key->phy.priority = skb->priority;
        if (OVS_CB(skb)->tun_key)
                memcpy(&key->tun_key, OVS_CB(skb)->tun_key, sizeof(key->tun_key));
        key->phy.in_port = in_port;
        key->phy.skb_mark = skb->mark;

        skb_reset_mac_header(skb);

        /* Link layer.  We are guaranteed to have at least the 14 byte Ethernet
         * header in the linear data area.
         */
        eth = eth_hdr(skb);
        memcpy(key->eth.src, eth->h_source, ETH_ALEN);
        memcpy(key->eth.dst, eth->h_dest, ETH_ALEN);

        __skb_pull(skb, 2 * ETH_ALEN);
        /* We are going to push all headers that we pull, so no need to
         * update skb->csum here.
         */

        if (vlan_tx_tag_present(skb))
                key->eth.tci = htons(skb->vlan_tci);
        else if (eth->h_proto == htons(ETH_P_8021Q))
                if (unlikely(parse_vlan(skb, key)))
                        return -ENOMEM;

        key->eth.type = parse_ethertype(skb);
        if (unlikely(key->eth.type == htons(0)))
                return -ENOMEM;

        skb_reset_network_header(skb);
        __skb_push(skb, skb->data - skb_mac_header(skb));

        /* Network layer. */
        if (key->eth.type == htons(ETH_P_IP)) {
                struct iphdr *nh;
                __be16 offset;

                error = check_iphdr(skb);
                if (unlikely(error)) {
                        if (error == -EINVAL) {
                                skb->transport_header = skb->network_header;
                                error = 0;
                        }
                        return error;
                }

                nh = ip_hdr(skb);
                key->ipv4.addr.src = nh->saddr;
                key->ipv4.addr.dst = nh->daddr;

                key->ip.proto = nh->protocol;
                key->ip.tos = nh->tos;
                key->ip.ttl = nh->ttl;

                offset = nh->frag_off & htons(IP_OFFSET);
                if (offset) {
                        key->ip.frag = OVS_FRAG_TYPE_LATER;
                        return 0;
                }
                if (nh->frag_off & htons(IP_MF) ||
                         skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
                        key->ip.frag = OVS_FRAG_TYPE_FIRST;

                /* Transport layer. */
                if (key->ip.proto == IPPROTO_TCP) {
                        if (tcphdr_ok(skb)) {
                                struct tcphdr *tcp = tcp_hdr(skb);
                                key->ipv4.tp.src = tcp->source;
                                key->ipv4.tp.dst = tcp->dest;
                        }
                } else if (key->ip.proto == IPPROTO_UDP) {
                        if (udphdr_ok(skb)) {
                                struct udphdr *udp = udp_hdr(skb);
                                key->ipv4.tp.src = udp->source;
                                key->ipv4.tp.dst = udp->dest;
                        }
                } else if (key->ip.proto == IPPROTO_SCTP) {
                        if (sctphdr_ok(skb)) {
                                struct sctphdr *sctp = sctp_hdr(skb);
                                key->ipv4.tp.src = sctp->source;
                                key->ipv4.tp.dst = sctp->dest;
                        }
                } else if (key->ip.proto == IPPROTO_ICMP) {
                        if (icmphdr_ok(skb)) {
                                struct icmphdr *icmp = icmp_hdr(skb);
                                /* The ICMP type and code fields use the 16-bit
                                 * transport port fields, so we need to store
                                 * them in 16-bit network byte order. */
                                key->ipv4.tp.src = htons(icmp->type);
                                key->ipv4.tp.dst = htons(icmp->code);
                        }
                }

        } else if ((key->eth.type == htons(ETH_P_ARP) ||
                   key->eth.type == htons(ETH_P_RARP)) && arphdr_ok(skb)) {
                struct arp_eth_header *arp;

                arp = (struct arp_eth_header *)skb_network_header(skb);

                if (arp->ar_hrd == htons(ARPHRD_ETHER)
                                && arp->ar_pro == htons(ETH_P_IP)
                                && arp->ar_hln == ETH_ALEN
                                && arp->ar_pln == 4) {

                        /* We only match on the lower 8 bits of the opcode. */
                        if (ntohs(arp->ar_op) <= 0xff)
                                key->ip.proto = ntohs(arp->ar_op);
                        memcpy(&key->ipv4.addr.src, arp->ar_sip, sizeof(key->ipv4.addr.src));
                        memcpy(&key->ipv4.addr.dst, arp->ar_tip, sizeof(key->ipv4.addr.dst));
                        memcpy(key->ipv4.arp.sha, arp->ar_sha, ETH_ALEN);
                        memcpy(key->ipv4.arp.tha, arp->ar_tha, ETH_ALEN);
                }
        } else if (key->eth.type == htons(ETH_P_IPV6)) {
                int nh_len;             /* IPv6 Header + Extensions */

                nh_len = parse_ipv6hdr(skb, key);
                if (unlikely(nh_len < 0)) {
                        if (nh_len == -EINVAL) {
                                skb->transport_header = skb->network_header;
                                error = 0;
                        } else {
                                error = nh_len;
                        }
                        return error;
                }

                if (key->ip.frag == OVS_FRAG_TYPE_LATER)
                        return 0;
                if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
                        key->ip.frag = OVS_FRAG_TYPE_FIRST;

                /* Transport layer. */
                if (key->ip.proto == NEXTHDR_TCP) {
                        if (tcphdr_ok(skb)) {
                                struct tcphdr *tcp = tcp_hdr(skb);
                                key->ipv6.tp.src = tcp->source;
                                key->ipv6.tp.dst = tcp->dest;
                        }
                } else if (key->ip.proto == NEXTHDR_UDP) {
                        if (udphdr_ok(skb)) {
                                struct udphdr *udp = udp_hdr(skb);
                                key->ipv6.tp.src = udp->source;
                                key->ipv6.tp.dst = udp->dest;
                        }
                } else if (key->ip.proto == NEXTHDR_SCTP) {
                        if (sctphdr_ok(skb)) {
                                struct sctphdr *sctp = sctp_hdr(skb);
                                key->ipv6.tp.src = sctp->source;
                                key->ipv6.tp.dst = sctp->dest;
                        }
                } else if (key->ip.proto == NEXTHDR_ICMP) {
                        if (icmp6hdr_ok(skb)) {
                                error = parse_icmpv6(skb, key, nh_len);
                                if (error)
                                        return error;
                        }
                }

        }

        return 0;
}

static u32 ovs_flow_hash(const struct sw_flow_key *key, int key_start,
                         int key_end)
{
        u32 *hash_key = (u32 *)((u8 *)key + key_start);
        int hash_u32s = (key_end - key_start) >> 2;

        /* Make sure number of hash bytes are multiple of u32. */
        BUILD_BUG_ON(sizeof(long) % sizeof(u32));

        return jhash2(hash_key, hash_u32s, 0);
}

static int flow_key_start(const struct sw_flow_key *key)
{
        if (key->tun_key.ipv4_dst)
                return 0;
        else
                return rounddown(offsetof(struct sw_flow_key, phy),
                                          sizeof(long));
}

static bool __cmp_key(const struct sw_flow_key *key1,
                const struct sw_flow_key *key2,  int key_start, int key_end)
{
        const long *cp1 = (long *)((u8 *)key1 + key_start);
        const long *cp2 = (long *)((u8 *)key2 + key_start);
        long diffs = 0;
        int i;

        for (i = key_start; i < key_end;  i += sizeof(long))
                diffs |= *cp1++ ^ *cp2++;

        return diffs == 0;
}

static bool __flow_cmp_masked_key(const struct sw_flow *flow,
                const struct sw_flow_key *key, int key_start, int key_end)
{
        return __cmp_key(&flow->key, key, key_start, key_end);
}

static bool __flow_cmp_unmasked_key(const struct sw_flow *flow,
                  const struct sw_flow_key *key, int key_start, int key_end)
{
        return __cmp_key(&flow->unmasked_key, key, key_start, key_end);
}

bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow,
                const struct sw_flow_key *key, int key_end)
{
        int key_start;
        key_start = flow_key_start(key);

        return __flow_cmp_unmasked_key(flow, key, key_start, key_end);

}

struct sw_flow *ovs_flow_lookup_unmasked_key(struct flow_table *table,
                                       struct sw_flow_match *match)
{
        struct sw_flow_key *unmasked = match->key;
        int key_end = match->range.end;
        struct sw_flow *flow;

        flow = ovs_flow_lookup(table, unmasked);
        if (flow && (!ovs_flow_cmp_unmasked_key(flow, unmasked, key_end)))
                flow = NULL;

        return flow;
}

static struct sw_flow *ovs_masked_flow_lookup(struct flow_table *table,
                                    const struct sw_flow_key *unmasked,
                                    struct sw_flow_mask *mask)
{
        struct sw_flow *flow;
        struct hlist_head *head;
        int key_start = mask->range.start;
        int key_end = mask->range.end;
        u32 hash;
        struct sw_flow_key masked_key;

        ovs_flow_key_mask(&masked_key, unmasked, mask);
        hash = ovs_flow_hash(&masked_key, key_start, key_end);
        head = find_bucket(table, hash);
        hlist_for_each_entry_rcu(flow, head, hash_node[table->node_ver]) {
                if (flow->mask == mask &&
                    __flow_cmp_masked_key(flow, &masked_key,
                                          key_start, key_end))
                        return flow;
        }
        return NULL;
}

struct sw_flow *ovs_flow_lookup(struct flow_table *tbl,
                                const struct sw_flow_key *key)
{
        struct sw_flow *flow = NULL;
        struct sw_flow_mask *mask;

        list_for_each_entry_rcu(mask, tbl->mask_list, list) {
                flow = ovs_masked_flow_lookup(tbl, key, mask);
                if (flow)  /* Found */
                        break;
        }

        return flow;
}


void ovs_flow_insert(struct flow_table *table, struct sw_flow *flow)
{
        flow->hash = ovs_flow_hash(&flow->key, flow->mask->range.start,
                        flow->mask->range.end);
        __tbl_insert(table, flow);
}

void ovs_flow_remove(struct flow_table *table, struct sw_flow *flow)
{
        BUG_ON(table->count == 0);
        hlist_del_rcu(&flow->hash_node[table->node_ver]);
        table->count--;
}

/* The size of the argument for each %OVS_KEY_ATTR_* Netlink attribute.  */
const int ovs_key_lens[OVS_KEY_ATTR_MAX + 1] = {
        [OVS_KEY_ATTR_ENCAP] = -1,
        [OVS_KEY_ATTR_PRIORITY] = sizeof(u32),
        [OVS_KEY_ATTR_IN_PORT] = sizeof(u32),
        [OVS_KEY_ATTR_SKB_MARK] = sizeof(u32),
        [OVS_KEY_ATTR_ETHERNET] = sizeof(struct ovs_key_ethernet),
        [OVS_KEY_ATTR_VLAN] = sizeof(__be16),
        [OVS_KEY_ATTR_ETHERTYPE] = sizeof(__be16),
        [OVS_KEY_ATTR_IPV4] = sizeof(struct ovs_key_ipv4),
        [OVS_KEY_ATTR_IPV6] = sizeof(struct ovs_key_ipv6),
        [OVS_KEY_ATTR_TCP] = sizeof(struct ovs_key_tcp),
        [OVS_KEY_ATTR_UDP] = sizeof(struct ovs_key_udp),
        [OVS_KEY_ATTR_SCTP] = sizeof(struct ovs_key_sctp),
        [OVS_KEY_ATTR_ICMP] = sizeof(struct ovs_key_icmp),
        [OVS_KEY_ATTR_ICMPV6] = sizeof(struct ovs_key_icmpv6),
        [OVS_KEY_ATTR_ARP] = sizeof(struct ovs_key_arp),
        [OVS_KEY_ATTR_ND] = sizeof(struct ovs_key_nd),
        [OVS_KEY_ATTR_TUNNEL] = -1,
};

static bool is_all_zero(const u8 *fp, size_t size)
{
        int i;

        if (!fp)
                return false;

        for (i = 0; i < size; i++)
                if (fp[i])
                        return false;

        return true;
}

static int __parse_flow_nlattrs(const struct nlattr *attr,
                              const struct nlattr *a[],
                              u64 *attrsp, bool nz)
{
        const struct nlattr *nla;
        u32 attrs;
        int rem;

        attrs = *attrsp;
        nla_for_each_nested(nla, attr, rem) {
                u16 type = nla_type(nla);
                int expected_len;

                if (type > OVS_KEY_ATTR_MAX) {
                        OVS_NLERR("Unknown key attribute (type=%d, max=%d).\n",
                                  type, OVS_KEY_ATTR_MAX);
                        return -EINVAL;
                }

                if (attrs & (1 << type)) {
                        OVS_NLERR("Duplicate key attribute (type %d).\n", type);
                        return -EINVAL;
                }

                expected_len = ovs_key_lens[type];
                if (nla_len(nla) != expected_len && expected_len != -1) {
                        OVS_NLERR("Key attribute has unexpected length (type=%d"
                                  ", length=%d, expected=%d).\n", type,
                                  nla_len(nla), expected_len);
                        return -EINVAL;
                }

                if (!nz || !is_all_zero(nla_data(nla), expected_len)) {
                        attrs |= 1 << type;
                        a[type] = nla;
                }
        }
        if (rem) {
                OVS_NLERR("Message has %d unknown bytes.\n", rem);
                return -EINVAL;
        }

        *attrsp = attrs;
        return 0;
}

static int parse_flow_mask_nlattrs(const struct nlattr *attr,
                              const struct nlattr *a[], u64 *attrsp)
{
        return __parse_flow_nlattrs(attr, a, attrsp, true);
}

static int parse_flow_nlattrs(const struct nlattr *attr,
                              const struct nlattr *a[], u64 *attrsp)
{
        return __parse_flow_nlattrs(attr, a, attrsp, false);
}

int ovs_ipv4_tun_from_nlattr(const struct nlattr *attr,
                             struct sw_flow_match *match, bool is_mask)
{
        struct nlattr *a;
        int rem;
        bool ttl = false;
        __be16 tun_flags = 0;

        nla_for_each_nested(a, attr, rem) {
                int type = nla_type(a);
                static const u32 ovs_tunnel_key_lens[OVS_TUNNEL_KEY_ATTR_MAX + 1] = {
                        [OVS_TUNNEL_KEY_ATTR_ID] = sizeof(u64),
                        [OVS_TUNNEL_KEY_ATTR_IPV4_SRC] = sizeof(u32),
                        [OVS_TUNNEL_KEY_ATTR_IPV4_DST] = sizeof(u32),
                        [OVS_TUNNEL_KEY_ATTR_TOS] = 1,
                        [OVS_TUNNEL_KEY_ATTR_TTL] = 1,
                        [OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT] = 0,
                        [OVS_TUNNEL_KEY_ATTR_CSUM] = 0,
                };

                if (type > OVS_TUNNEL_KEY_ATTR_MAX) {
                        OVS_NLERR("Unknown IPv4 tunnel attribute (type=%d, max=%d).\n",
                        type, OVS_TUNNEL_KEY_ATTR_MAX);
                        return -EINVAL;
                }

                if (ovs_tunnel_key_lens[type] != nla_len(a)) {
                        OVS_NLERR("IPv4 tunnel attribute type has unexpected "
                                  " length (type=%d, length=%d, expected=%d).\n",
                                  type, nla_len(a), ovs_tunnel_key_lens[type]);
                        return -EINVAL;
                }

                switch (type) {
                case OVS_TUNNEL_KEY_ATTR_ID:
                        SW_FLOW_KEY_PUT(match, tun_key.tun_id,
                                        nla_get_be64(a), is_mask);
                        tun_flags |= TUNNEL_KEY;
                        break;
                case OVS_TUNNEL_KEY_ATTR_IPV4_SRC:
                        SW_FLOW_KEY_PUT(match, tun_key.ipv4_src,
                                        nla_get_be32(a), is_mask);
                        break;
                case OVS_TUNNEL_KEY_ATTR_IPV4_DST:
                        SW_FLOW_KEY_PUT(match, tun_key.ipv4_dst,
                                        nla_get_be32(a), is_mask);
                        break;
                case OVS_TUNNEL_KEY_ATTR_TOS:
                        SW_FLOW_KEY_PUT(match, tun_key.ipv4_tos,
                                        nla_get_u8(a), is_mask);
                        break;
                case OVS_TUNNEL_KEY_ATTR_TTL:
                        SW_FLOW_KEY_PUT(match, tun_key.ipv4_ttl,
                                        nla_get_u8(a), is_mask);
                        ttl = true;
                        break;
                case OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT:
                        tun_flags |= TUNNEL_DONT_FRAGMENT;
                        break;
                case OVS_TUNNEL_KEY_ATTR_CSUM:
                        tun_flags |= TUNNEL_CSUM;
                        break;
                default:
                        return -EINVAL;
                }
        }

        SW_FLOW_KEY_PUT(match, tun_key.tun_flags, tun_flags, is_mask);

        if (rem > 0) {
                OVS_NLERR("IPv4 tunnel attribute has %d unknown bytes.\n", rem);
                return -EINVAL;
        }

        if (!is_mask) {
                if (!match->key->tun_key.ipv4_dst) {
                        OVS_NLERR("IPv4 tunnel destination address is zero.\n");
                        return -EINVAL;
                }

                if (!ttl) {
                        OVS_NLERR("IPv4 tunnel TTL not specified.\n");
                        return -EINVAL;
                }
        }

        return 0;
}

int ovs_ipv4_tun_to_nlattr(struct sk_buff *skb,
                           const struct ovs_key_ipv4_tunnel *tun_key,
                           const struct ovs_key_ipv4_tunnel *output)
{
        struct nlattr *nla;

        nla = nla_nest_start(skb, OVS_KEY_ATTR_TUNNEL);
        if (!nla)
                return -EMSGSIZE;

        if (output->tun_flags & TUNNEL_KEY &&
            nla_put_be64(skb, OVS_TUNNEL_KEY_ATTR_ID, output->tun_id))
                return -EMSGSIZE;
        if (output->ipv4_src &&
                nla_put_be32(skb, OVS_TUNNEL_KEY_ATTR_IPV4_SRC, output->ipv4_src))
                return -EMSGSIZE;
        if (output->ipv4_dst &&
                nla_put_be32(skb, OVS_TUNNEL_KEY_ATTR_IPV4_DST, output->ipv4_dst))
                return -EMSGSIZE;
        if (output->ipv4_tos &&
                nla_put_u8(skb, OVS_TUNNEL_KEY_ATTR_TOS, output->ipv4_tos))
                return -EMSGSIZE;
        if (nla_put_u8(skb, OVS_TUNNEL_KEY_ATTR_TTL, output->ipv4_ttl))
                return -EMSGSIZE;
        if ((output->tun_flags & TUNNEL_DONT_FRAGMENT) &&
                nla_put_flag(skb, OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT))
                return -EMSGSIZE;
        if ((output->tun_flags & TUNNEL_CSUM) &&
                nla_put_flag(skb, OVS_TUNNEL_KEY_ATTR_CSUM))
                return -EMSGSIZE;

        nla_nest_end(skb, nla);
        return 0;
}

static int metadata_from_nlattrs(struct sw_flow_match *match,  u64 *attrs,
                const struct nlattr **a, bool is_mask)
{
        if (*attrs & (1 << OVS_KEY_ATTR_PRIORITY)) {
                SW_FLOW_KEY_PUT(match, phy.priority,
                          nla_get_u32(a[OVS_KEY_ATTR_PRIORITY]), is_mask);
                *attrs &= ~(1 << OVS_KEY_ATTR_PRIORITY);
        }

        if (*attrs & (1 << OVS_KEY_ATTR_IN_PORT)) {
                u32 in_port = nla_get_u32(a[OVS_KEY_ATTR_IN_PORT]);

                if (is_mask)
                        in_port = 0xffffffff; /* Always exact match in_port. */
                else if (in_port >= DP_MAX_PORTS)
                        return -EINVAL;

                SW_FLOW_KEY_PUT(match, phy.in_port, in_port, is_mask);
                *attrs &= ~(1 << OVS_KEY_ATTR_IN_PORT);
        } else if (!is_mask) {
                SW_FLOW_KEY_PUT(match, phy.in_port, DP_MAX_PORTS, is_mask);
        }

        if (*attrs & (1 << OVS_KEY_ATTR_SKB_MARK)) {
                uint32_t mark = nla_get_u32(a[OVS_KEY_ATTR_SKB_MARK]);

                SW_FLOW_KEY_PUT(match, phy.skb_mark, mark, is_mask);
                *attrs &= ~(1 << OVS_KEY_ATTR_SKB_MARK);
        }
        if (*attrs & (1 << OVS_KEY_ATTR_TUNNEL)) {
                if (ovs_ipv4_tun_from_nlattr(a[OVS_KEY_ATTR_TUNNEL], match,
                                        is_mask))
                        return -EINVAL;
                *attrs &= ~(1 << OVS_KEY_ATTR_TUNNEL);
        }
        return 0;
}

static int ovs_key_from_nlattrs(struct sw_flow_match *match,  u64 attrs,
                const struct nlattr **a, bool is_mask)
{
        int err;
        u64 orig_attrs = attrs;

        err = metadata_from_nlattrs(match, &attrs, a, is_mask);
        if (err)
                return err;

        if (attrs & (1 << OVS_KEY_ATTR_ETHERNET)) {
                const struct ovs_key_ethernet *eth_key;

                eth_key = nla_data(a[OVS_KEY_ATTR_ETHERNET]);
                SW_FLOW_KEY_MEMCPY(match, eth.src,
                                eth_key->eth_src, ETH_ALEN, is_mask);
                SW_FLOW_KEY_MEMCPY(match, eth.dst,
                                eth_key->eth_dst, ETH_ALEN, is_mask);
                attrs &= ~(1 << OVS_KEY_ATTR_ETHERNET);
        }

        if (attrs & (1 << OVS_KEY_ATTR_VLAN)) {
                __be16 tci;

                tci = nla_get_be16(a[OVS_KEY_ATTR_VLAN]);
                if (!(tci & htons(VLAN_TAG_PRESENT))) {
                        if (is_mask)
                                OVS_NLERR("VLAN TCI mask does not have exact match for VLAN_TAG_PRESENT bit.\n");
                        else
                                OVS_NLERR("VLAN TCI does not have VLAN_TAG_PRESENT bit set.\n");

                        return -EINVAL;
                }

                SW_FLOW_KEY_PUT(match, eth.tci, tci, is_mask);
                attrs &= ~(1 << OVS_KEY_ATTR_VLAN);
        } else if (!is_mask)
                SW_FLOW_KEY_PUT(match, eth.tci, htons(0xffff), true);

        if (attrs & (1 << OVS_KEY_ATTR_ETHERTYPE)) {
                __be16 eth_type;

                eth_type = nla_get_be16(a[OVS_KEY_ATTR_ETHERTYPE]);
                if (is_mask) {
                        /* Always exact match EtherType. */
                        eth_type = htons(0xffff);
                } else if (ntohs(eth_type) < ETH_P_802_3_MIN) {
                        OVS_NLERR("EtherType is less than minimum (type=%x, min=%x).\n",
                                        ntohs(eth_type), ETH_P_802_3_MIN);
                        return -EINVAL;
                }

                SW_FLOW_KEY_PUT(match, eth.type, eth_type, is_mask);
                attrs &= ~(1 << OVS_KEY_ATTR_ETHERTYPE);
        } else if (!is_mask) {
                SW_FLOW_KEY_PUT(match, eth.type, htons(ETH_P_802_2), is_mask);
        }

        if (attrs & (1 << OVS_KEY_ATTR_IPV4)) {
                const struct ovs_key_ipv4 *ipv4_key;

                ipv4_key = nla_data(a[OVS_KEY_ATTR_IPV4]);
                if (!is_mask && ipv4_key->ipv4_frag > OVS_FRAG_TYPE_MAX) {
                        OVS_NLERR("Unknown IPv4 fragment type (value=%d, max=%d).\n",
                                ipv4_key->ipv4_frag, OVS_FRAG_TYPE_MAX);
                        return -EINVAL;
                }
                SW_FLOW_KEY_PUT(match, ip.proto,
                                ipv4_key->ipv4_proto, is_mask);
                SW_FLOW_KEY_PUT(match, ip.tos,
                                ipv4_key->ipv4_tos, is_mask);
                SW_FLOW_KEY_PUT(match, ip.ttl,
                                ipv4_key->ipv4_ttl, is_mask);
                SW_FLOW_KEY_PUT(match, ip.frag,
                                ipv4_key->ipv4_frag, is_mask);
                SW_FLOW_KEY_PUT(match, ipv4.addr.src,
                                ipv4_key->ipv4_src, is_mask);
                SW_FLOW_KEY_PUT(match, ipv4.addr.dst,
                                ipv4_key->ipv4_dst, is_mask);
                attrs &= ~(1 << OVS_KEY_ATTR_IPV4);
        }

        if (attrs & (1 << OVS_KEY_ATTR_IPV6)) {
                const struct ovs_key_ipv6 *ipv6_key;

                ipv6_key = nla_data(a[OVS_KEY_ATTR_IPV6]);
                if (!is_mask && ipv6_key->ipv6_frag > OVS_FRAG_TYPE_MAX) {
                        OVS_NLERR("Unknown IPv6 fragment type (value=%d, max=%d).\n",
                                ipv6_key->ipv6_frag, OVS_FRAG_TYPE_MAX);
                        return -EINVAL;
                }
                SW_FLOW_KEY_PUT(match, ipv6.label,
                                ipv6_key->ipv6_label, is_mask);
                SW_FLOW_KEY_PUT(match, ip.proto,
                                ipv6_key->ipv6_proto, is_mask);
                SW_FLOW_KEY_PUT(match, ip.tos,
                                ipv6_key->ipv6_tclass, is_mask);
                SW_FLOW_KEY_PUT(match, ip.ttl,
                                ipv6_key->ipv6_hlimit, is_mask);
                SW_FLOW_KEY_PUT(match, ip.frag,
                                ipv6_key->ipv6_frag, is_mask);
                SW_FLOW_KEY_MEMCPY(match, ipv6.addr.src,
                                ipv6_key->ipv6_src,
                                sizeof(match->key->ipv6.addr.src),
                                is_mask);
                SW_FLOW_KEY_MEMCPY(match, ipv6.addr.dst,
                                ipv6_key->ipv6_dst,
                                sizeof(match->key->ipv6.addr.dst),
                                is_mask);

                attrs &= ~(1 << OVS_KEY_ATTR_IPV6);
        }

        if (attrs & (1 << OVS_KEY_ATTR_ARP)) {
                const struct ovs_key_arp *arp_key;

                arp_key = nla_data(a[OVS_KEY_ATTR_ARP]);
                if (!is_mask && (arp_key->arp_op & htons(0xff00))) {
                        OVS_NLERR("Unknown ARP opcode (opcode=%d).\n",
                                  arp_key->arp_op);
                        return -EINVAL;
                }

                SW_FLOW_KEY_PUT(match, ipv4.addr.src,
                                arp_key->arp_sip, is_mask);
                SW_FLOW_KEY_PUT(match, ipv4.addr.dst,
                        arp_key->arp_tip, is_mask);
                SW_FLOW_KEY_PUT(match, ip.proto,
                                ntohs(arp_key->arp_op), is_mask);
                SW_FLOW_KEY_MEMCPY(match, ipv4.arp.sha,
                                arp_key->arp_sha, ETH_ALEN, is_mask);
                SW_FLOW_KEY_MEMCPY(match, ipv4.arp.tha,
                                arp_key->arp_tha, ETH_ALEN, is_mask);

                attrs &= ~(1 << OVS_KEY_ATTR_ARP);
        }

        if (attrs & (1 << OVS_KEY_ATTR_TCP)) {
                const struct ovs_key_tcp *tcp_key;

                tcp_key = nla_data(a[OVS_KEY_ATTR_TCP]);
                if (orig_attrs & (1 << OVS_KEY_ATTR_IPV4)) {
                        SW_FLOW_KEY_PUT(match, ipv4.tp.src,
                                        tcp_key->tcp_src, is_mask);
                        SW_FLOW_KEY_PUT(match, ipv4.tp.dst,
                                        tcp_key->tcp_dst, is_mask);
                } else {
                        SW_FLOW_KEY_PUT(match, ipv6.tp.src,
                                        tcp_key->tcp_src, is_mask);
                        SW_FLOW_KEY_PUT(match, ipv6.tp.dst,
                                        tcp_key->tcp_dst, is_mask);
                }
                attrs &= ~(1 << OVS_KEY_ATTR_TCP);
        }

        if (attrs & (1 << OVS_KEY_ATTR_UDP)) {
                const struct ovs_key_udp *udp_key;

                udp_key = nla_data(a[OVS_KEY_ATTR_UDP]);
                if (orig_attrs & (1 << OVS_KEY_ATTR_IPV4)) {
                        SW_FLOW_KEY_PUT(match, ipv4.tp.src,
                                        udp_key->udp_src, is_mask);
                        SW_FLOW_KEY_PUT(match, ipv4.tp.dst,
                                        udp_key->udp_dst, is_mask);
                } else {
                        SW_FLOW_KEY_PUT(match, ipv6.tp.src,
                                        udp_key->udp_src, is_mask);
                        SW_FLOW_KEY_PUT(match, ipv6.tp.dst,
                                        udp_key->udp_dst, is_mask);
                }
                attrs &= ~(1 << OVS_KEY_ATTR_UDP);
        }

        if (attrs & (1 << OVS_KEY_ATTR_SCTP)) {
                const struct ovs_key_sctp *sctp_key;

                sctp_key = nla_data(a[OVS_KEY_ATTR_SCTP]);
                if (orig_attrs & (1 << OVS_KEY_ATTR_IPV4)) {
                        SW_FLOW_KEY_PUT(match, ipv4.tp.src,
                                        sctp_key->sctp_src, is_mask);
                        SW_FLOW_KEY_PUT(match, ipv4.tp.dst,
                                        sctp_key->sctp_dst, is_mask);
                } else {
                        SW_FLOW_KEY_PUT(match, ipv6.tp.src,
                                        sctp_key->sctp_src, is_mask);
                        SW_FLOW_KEY_PUT(match, ipv6.tp.dst,
                                        sctp_key->sctp_dst, is_mask);
                }
                attrs &= ~(1 << OVS_KEY_ATTR_SCTP);
        }

        if (attrs & (1 << OVS_KEY_ATTR_ICMP)) {
                const struct ovs_key_icmp *icmp_key;

                icmp_key = nla_data(a[OVS_KEY_ATTR_ICMP]);
                SW_FLOW_KEY_PUT(match, ipv4.tp.src,
                                htons(icmp_key->icmp_type), is_mask);
                SW_FLOW_KEY_PUT(match, ipv4.tp.dst,
                                htons(icmp_key->icmp_code), is_mask);
                attrs &= ~(1 << OVS_KEY_ATTR_ICMP);
        }

        if (attrs & (1 << OVS_KEY_ATTR_ICMPV6)) {
                const struct ovs_key_icmpv6 *icmpv6_key;

                icmpv6_key = nla_data(a[OVS_KEY_ATTR_ICMPV6]);
                SW_FLOW_KEY_PUT(match, ipv6.tp.src,
                                htons(icmpv6_key->icmpv6_type), is_mask);
                SW_FLOW_KEY_PUT(match, ipv6.tp.dst,
                                htons(icmpv6_key->icmpv6_code), is_mask);
                attrs &= ~(1 << OVS_KEY_ATTR_ICMPV6);
        }

        if (attrs & (1 << OVS_KEY_ATTR_ND)) {
                const struct ovs_key_nd *nd_key;

                nd_key = nla_data(a[OVS_KEY_ATTR_ND]);
                SW_FLOW_KEY_MEMCPY(match, ipv6.nd.target,
                        nd_key->nd_target,
                        sizeof(match->key->ipv6.nd.target),
                        is_mask);
                SW_FLOW_KEY_MEMCPY(match, ipv6.nd.sll,
                        nd_key->nd_sll, ETH_ALEN, is_mask);
                SW_FLOW_KEY_MEMCPY(match, ipv6.nd.tll,
                                nd_key->nd_tll, ETH_ALEN, is_mask);
                attrs &= ~(1 << OVS_KEY_ATTR_ND);
        }

        if (attrs != 0)
                return -EINVAL;

        return 0;
}

/**
 * ovs_match_from_nlattrs - parses Netlink attributes into a flow key and
 * mask. In case the 'mask' is NULL, the flow is treated as exact match
 * flow. Otherwise, it is treated as a wildcarded flow, except the mask
 * does not include any don't care bit.
 * @match: receives the extracted flow match information.
 * @key: Netlink attribute holding nested %OVS_KEY_ATTR_* Netlink attribute
 * sequence. The fields should of the packet that triggered the creation
 * of this flow.
 * @mask: Optional. Netlink attribute holding nested %OVS_KEY_ATTR_* Netlink
 * attribute specifies the mask field of the wildcarded flow.
 */
int ovs_match_from_nlattrs(struct sw_flow_match *match,
                           const struct nlattr *key,
                           const struct nlattr *mask)
{
        const struct nlattr *a[OVS_KEY_ATTR_MAX + 1];
        const struct nlattr *encap;
        u64 key_attrs = 0;
        u64 mask_attrs = 0;
        bool encap_valid = false;
        int err;

        err = parse_flow_nlattrs(key, a, &key_attrs);
        if (err)
                return err;

        if ((key_attrs & (1 << OVS_KEY_ATTR_ETHERNET)) &&
            (key_attrs & (1 << OVS_KEY_ATTR_ETHERTYPE)) &&
            (nla_get_be16(a[OVS_KEY_ATTR_ETHERTYPE]) == htons(ETH_P_8021Q))) {
                __be16 tci;

                if (!((key_attrs & (1 << OVS_KEY_ATTR_VLAN)) &&
                      (key_attrs & (1 << OVS_KEY_ATTR_ENCAP)))) {
                        OVS_NLERR("Invalid Vlan frame.\n");
                        return -EINVAL;
                }

                key_attrs &= ~(1 << OVS_KEY_ATTR_ETHERTYPE);
                tci = nla_get_be16(a[OVS_KEY_ATTR_VLAN]);
                encap = a[OVS_KEY_ATTR_ENCAP];
                key_attrs &= ~(1 << OVS_KEY_ATTR_ENCAP);
                encap_valid = true;

                if (tci & htons(VLAN_TAG_PRESENT)) {
                        err = parse_flow_nlattrs(encap, a, &key_attrs);
                        if (err)
                                return err;
                } else if (!tci) {
                        /* Corner case for truncated 802.1Q header. */
                        if (nla_len(encap)) {
                                OVS_NLERR("Truncated 802.1Q header has non-zero encap attribute.\n");
                                return -EINVAL;
                        }
                } else {
                        OVS_NLERR("Encap attribute is set for a non-VLAN frame.\n");
                        return  -EINVAL;
                }
        }

        err = ovs_key_from_nlattrs(match, key_attrs, a, false);
        if (err)
                return err;

        if (mask) {
                err = parse_flow_mask_nlattrs(mask, a, &mask_attrs);
                if (err)
                        return err;

                if (mask_attrs & 1ULL << OVS_KEY_ATTR_ENCAP)  {
                        __be16 eth_type = 0;
                        __be16 tci = 0;

                        if (!encap_valid) {
                                OVS_NLERR("Encap mask attribute is set for non-VLAN frame.\n");
                                return  -EINVAL;
                        }

                        mask_attrs &= ~(1 << OVS_KEY_ATTR_ENCAP);
                        if (a[OVS_KEY_ATTR_ETHERTYPE])
                                eth_type = nla_get_be16(a[OVS_KEY_ATTR_ETHERTYPE]);

                        if (eth_type == htons(0xffff)) {
                                mask_attrs &= ~(1 << OVS_KEY_ATTR_ETHERTYPE);
                                encap = a[OVS_KEY_ATTR_ENCAP];
                                err = parse_flow_mask_nlattrs(encap, a, &mask_attrs);
                        } else {
                                OVS_NLERR("VLAN frames must have an exact match on the TPID (mask=%x).\n",
                                                ntohs(eth_type));
                                return -EINVAL;
                        }

                        if (a[OVS_KEY_ATTR_VLAN])
                                tci = nla_get_be16(a[OVS_KEY_ATTR_VLAN]);

                        if (!(tci & htons(VLAN_TAG_PRESENT))) {
                                OVS_NLERR("VLAN tag present bit must have an exact match (tci_mask=%x).\n", ntohs(tci));
                                return -EINVAL;
                        }
                }

                err = ovs_key_from_nlattrs(match, mask_attrs, a, true);
                if (err)
                        return err;
        } else {
                /* Populate exact match flow's key mask. */
                if (match->mask)
                        ovs_sw_flow_mask_set(match->mask, &match->range, 0xff);
        }

        if (!ovs_match_validate(match, key_attrs, mask_attrs))
                return -EINVAL;

        return 0;
}

/**
 * ovs_flow_metadata_from_nlattrs - parses Netlink attributes into a flow key.
 * @flow: Receives extracted in_port, priority, tun_key and skb_mark.
 * @attr: Netlink attribute holding nested %OVS_KEY_ATTR_* Netlink attribute
 * sequence.
 *
 * This parses a series of Netlink attributes that form a flow key, which must
 * take the same form accepted by flow_from_nlattrs(), but only enough of it to
 * get the metadata, that is, the parts of the flow key that cannot be
 * extracted from the packet itself.
 */

int ovs_flow_metadata_from_nlattrs(struct sw_flow *flow,
                const struct nlattr *attr)
{
        struct ovs_key_ipv4_tunnel *tun_key = &flow->key.tun_key;
        const struct nlattr *a[OVS_KEY_ATTR_MAX + 1];
        u64 attrs = 0;
        int err;
        struct sw_flow_match match;

        flow->key.phy.in_port = DP_MAX_PORTS;
        flow->key.phy.priority = 0;
        flow->key.phy.skb_mark = 0;
        memset(tun_key, 0, sizeof(flow->key.tun_key));

        err = parse_flow_nlattrs(attr, a, &attrs);
        if (err)
                return -EINVAL;

        memset(&match, 0, sizeof(match));
        match.key = &flow->key;

        err = metadata_from_nlattrs(&match, &attrs, a, false);
        if (err)
                return err;

        return 0;
}

int ovs_flow_to_nlattrs(const struct sw_flow_key *swkey,
                const struct sw_flow_key *output, struct sk_buff *skb)
{
        struct ovs_key_ethernet *eth_key;
        struct nlattr *nla, *encap;
        bool is_mask = (swkey != output);

        if (nla_put_u32(skb, OVS_KEY_ATTR_PRIORITY, output->phy.priority))
                goto nla_put_failure;

        if ((swkey->tun_key.ipv4_dst || is_mask) &&
            ovs_ipv4_tun_to_nlattr(skb, &swkey->tun_key, &output->tun_key))
                goto nla_put_failure;

        if (swkey->phy.in_port == DP_MAX_PORTS) {
                if (is_mask && (output->phy.in_port == 0xffff))
                        if (nla_put_u32(skb, OVS_KEY_ATTR_IN_PORT, 0xffffffff))
                                goto nla_put_failure;
        } else {
                u16 upper_u16;
                upper_u16 = !is_mask ? 0 : 0xffff;

                if (nla_put_u32(skb, OVS_KEY_ATTR_IN_PORT,
                                (upper_u16 << 16) | output->phy.in_port))
                        goto nla_put_failure;
        }

        if (nla_put_u32(skb, OVS_KEY_ATTR_SKB_MARK, output->phy.skb_mark))
                goto nla_put_failure;

        nla = nla_reserve(skb, OVS_KEY_ATTR_ETHERNET, sizeof(*eth_key));
        if (!nla)
                goto nla_put_failure;

        eth_key = nla_data(nla);
        memcpy(eth_key->eth_src, output->eth.src, ETH_ALEN);
        memcpy(eth_key->eth_dst, output->eth.dst, ETH_ALEN);

        if (swkey->eth.tci || swkey->eth.type == htons(ETH_P_8021Q)) {
                __be16 eth_type;
                eth_type = !is_mask ? htons(ETH_P_8021Q) : htons(0xffff);
                if (nla_put_be16(skb, OVS_KEY_ATTR_ETHERTYPE, eth_type) ||
                    nla_put_be16(skb, OVS_KEY_ATTR_VLAN, output->eth.tci))
                        goto nla_put_failure;
                encap = nla_nest_start(skb, OVS_KEY_ATTR_ENCAP);
                if (!swkey->eth.tci)
                        goto unencap;
        } else
                encap = NULL;

        if (swkey->eth.type == htons(ETH_P_802_2)) {
                /*
                 * Ethertype 802.2 is represented in the netlink with omitted
                 * OVS_KEY_ATTR_ETHERTYPE in the flow key attribute, and
                 * 0xffff in the mask attribute.  Ethertype can also
                 * be wildcarded.
                 */
                if (is_mask && output->eth.type)
                        if (nla_put_be16(skb, OVS_KEY_ATTR_ETHERTYPE,
                                                output->eth.type))
                                goto nla_put_failure;
                goto unencap;
        }

        if (nla_put_be16(skb, OVS_KEY_ATTR_ETHERTYPE, output->eth.type))
                goto nla_put_failure;

        if (swkey->eth.type == htons(ETH_P_IP)) {
                struct ovs_key_ipv4 *ipv4_key;

                nla = nla_reserve(skb, OVS_KEY_ATTR_IPV4, sizeof(*ipv4_key));
                if (!nla)
                        goto nla_put_failure;
                ipv4_key = nla_data(nla);
                ipv4_key->ipv4_src = output->ipv4.addr.src;
                ipv4_key->ipv4_dst = output->ipv4.addr.dst;
                ipv4_key->ipv4_proto = output->ip.proto;
                ipv4_key->ipv4_tos = output->ip.tos;
                ipv4_key->ipv4_ttl = output->ip.ttl;
                ipv4_key->ipv4_frag = output->ip.frag;
        } else if (swkey->eth.type == htons(ETH_P_IPV6)) {
                struct ovs_key_ipv6 *ipv6_key;

                nla = nla_reserve(skb, OVS_KEY_ATTR_IPV6, sizeof(*ipv6_key));
                if (!nla)
                        goto nla_put_failure;
                ipv6_key = nla_data(nla);
                memcpy(ipv6_key->ipv6_src, &output->ipv6.addr.src,
                                sizeof(ipv6_key->ipv6_src));
                memcpy(ipv6_key->ipv6_dst, &output->ipv6.addr.dst,
                                sizeof(ipv6_key->ipv6_dst));
                ipv6_key->ipv6_label = output->ipv6.label;
                ipv6_key->ipv6_proto = output->ip.proto;
                ipv6_key->ipv6_tclass = output->ip.tos;
                ipv6_key->ipv6_hlimit = output->ip.ttl;
                ipv6_key->ipv6_frag = output->ip.frag;
        } else if (swkey->eth.type == htons(ETH_P_ARP) ||
                   swkey->eth.type == htons(ETH_P_RARP)) {
                struct ovs_key_arp *arp_key;

                nla = nla_reserve(skb, OVS_KEY_ATTR_ARP, sizeof(*arp_key));
                if (!nla)
                        goto nla_put_failure;
                arp_key = nla_data(nla);
                memset(arp_key, 0, sizeof(struct ovs_key_arp));
                arp_key->arp_sip = output->ipv4.addr.src;
                arp_key->arp_tip = output->ipv4.addr.dst;
                arp_key->arp_op = htons(output->ip.proto);
                memcpy(arp_key->arp_sha, output->ipv4.arp.sha, ETH_ALEN);
                memcpy(arp_key->arp_tha, output->ipv4.arp.tha, ETH_ALEN);
        }

        if ((swkey->eth.type == htons(ETH_P_IP) ||
             swkey->eth.type == htons(ETH_P_IPV6)) &&
             swkey->ip.frag != OVS_FRAG_TYPE_LATER) {

                if (swkey->ip.proto == IPPROTO_TCP) {
                        struct ovs_key_tcp *tcp_key;

                        nla = nla_reserve(skb, OVS_KEY_ATTR_TCP, sizeof(*tcp_key));
                        if (!nla)
                                goto nla_put_failure;
                        tcp_key = nla_data(nla);
                        if (swkey->eth.type == htons(ETH_P_IP)) {
                                tcp_key->tcp_src = output->ipv4.tp.src;
                                tcp_key->tcp_dst = output->ipv4.tp.dst;
                        } else if (swkey->eth.type == htons(ETH_P_IPV6)) {
                                tcp_key->tcp_src = output->ipv6.tp.src;
                                tcp_key->tcp_dst = output->ipv6.tp.dst;
                        }
                } else if (swkey->ip.proto == IPPROTO_UDP) {
                        struct ovs_key_udp *udp_key;

                        nla = nla_reserve(skb, OVS_KEY_ATTR_UDP, sizeof(*udp_key));
                        if (!nla)
                                goto nla_put_failure;
                        udp_key = nla_data(nla);
                        if (swkey->eth.type == htons(ETH_P_IP)) {
                                udp_key->udp_src = output->ipv4.tp.src;
                                udp_key->udp_dst = output->ipv4.tp.dst;
                        } else if (swkey->eth.type == htons(ETH_P_IPV6)) {
                                udp_key->udp_src = output->ipv6.tp.src;
                                udp_key->udp_dst = output->ipv6.tp.dst;
                        }
                } else if (swkey->ip.proto == IPPROTO_SCTP) {
                        struct ovs_key_sctp *sctp_key;

                        nla = nla_reserve(skb, OVS_KEY_ATTR_SCTP, sizeof(*sctp_key));
                        if (!nla)
                                goto nla_put_failure;
                        sctp_key = nla_data(nla);
                        if (swkey->eth.type == htons(ETH_P_IP)) {
                                sctp_key->sctp_src = swkey->ipv4.tp.src;
                                sctp_key->sctp_dst = swkey->ipv4.tp.dst;
                        } else if (swkey->eth.type == htons(ETH_P_IPV6)) {
                                sctp_key->sctp_src = swkey->ipv6.tp.src;
                                sctp_key->sctp_dst = swkey->ipv6.tp.dst;
                        }
                } else if (swkey->eth.type == htons(ETH_P_IP) &&
                           swkey->ip.proto == IPPROTO_ICMP) {
                        struct ovs_key_icmp *icmp_key;

                        nla = nla_reserve(skb, OVS_KEY_ATTR_ICMP, sizeof(*icmp_key));
                        if (!nla)
                                goto nla_put_failure;
                        icmp_key = nla_data(nla);
                        icmp_key->icmp_type = ntohs(output->ipv4.tp.src);
                        icmp_key->icmp_code = ntohs(output->ipv4.tp.dst);
                } else if (swkey->eth.type == htons(ETH_P_IPV6) &&
                           swkey->ip.proto == IPPROTO_ICMPV6) {
                        struct ovs_key_icmpv6 *icmpv6_key;

                        nla = nla_reserve(skb, OVS_KEY_ATTR_ICMPV6,
                                                sizeof(*icmpv6_key));
                        if (!nla)
                                goto nla_put_failure;
                        icmpv6_key = nla_data(nla);
                        icmpv6_key->icmpv6_type = ntohs(output->ipv6.tp.src);
                        icmpv6_key->icmpv6_code = ntohs(output->ipv6.tp.dst);

                        if (icmpv6_key->icmpv6_type == NDISC_NEIGHBOUR_SOLICITATION ||
                            icmpv6_key->icmpv6_type == NDISC_NEIGHBOUR_ADVERTISEMENT) {
                                struct ovs_key_nd *nd_key;

                                nla = nla_reserve(skb, OVS_KEY_ATTR_ND, sizeof(*nd_key));
                                if (!nla)
                                        goto nla_put_failure;
                                nd_key = nla_data(nla);
                                memcpy(nd_key->nd_target, &output->ipv6.nd.target,
                                                        sizeof(nd_key->nd_target));
                                memcpy(nd_key->nd_sll, output->ipv6.nd.sll, ETH_ALEN);
                                memcpy(nd_key->nd_tll, output->ipv6.nd.tll, ETH_ALEN);
                        }
                }
        }

unencap:
        if (encap)
                nla_nest_end(skb, encap);

        return 0;

nla_put_failure:
        return -EMSGSIZE;
}

/* Initializes the flow module.
 * Returns zero if successful or a negative error code. */
int ovs_flow_init(void)
{
        BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long));
        BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long));

        flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0,
                                        0, NULL);
        if (flow_cache == NULL)
                return -ENOMEM;

        return 0;
}

/* Uninitializes the flow module. */
void ovs_flow_exit(void)
{
        kmem_cache_destroy(flow_cache);
}

struct sw_flow_mask *ovs_sw_flow_mask_alloc(void)
{
        struct sw_flow_mask *mask;

        mask = kmalloc(sizeof(*mask), GFP_KERNEL);
        if (mask)
                mask->ref_count = 0;

        return mask;
}

void ovs_sw_flow_mask_add_ref(struct sw_flow_mask *mask)
{
        mask->ref_count++;
}

void ovs_sw_flow_mask_del_ref(struct sw_flow_mask *mask, bool deferred)
{
        if (!mask)
                return;

        BUG_ON(!mask->ref_count);
        mask->ref_count--;

        if (!mask->ref_count) {
                list_del_rcu(&mask->list);
                if (deferred)
                        kfree_rcu(mask, rcu);
                else
                        kfree(mask);
        }
}

static bool ovs_sw_flow_mask_equal(const struct sw_flow_mask *a,
                const struct sw_flow_mask *b)
{
        u8 *a_ = (u8 *)&a->key + a->range.start;
        u8 *b_ = (u8 *)&b->key + b->range.start;

        return  (a->range.end == b->range.end)
                && (a->range.start == b->range.start)
                && (memcmp(a_, b_, range_n_bytes(&a->range)) == 0);
}

struct sw_flow_mask *ovs_sw_flow_mask_find(const struct flow_table *tbl,
                                           const struct sw_flow_mask *mask)
{
        struct list_head *ml;

        list_for_each(ml, tbl->mask_list) {
                struct sw_flow_mask *m;
                m = container_of(ml, struct sw_flow_mask, list);
                if (ovs_sw_flow_mask_equal(mask, m))
                        return m;
        }

        return NULL;
}

/**
 * add a new mask into the mask list.
 * The caller needs to make sure that 'mask' is not the same
 * as any masks that are already on the list.
 */
void ovs_sw_flow_mask_insert(struct flow_table *tbl, struct sw_flow_mask *mask)
{
        list_add_rcu(&mask->list, tbl->mask_list);
}

/**
 * Set 'range' fields in the mask to the value of 'val'.
 */
static void ovs_sw_flow_mask_set(struct sw_flow_mask *mask,
                struct sw_flow_key_range *range, u8 val)
{
        u8 *m = (u8 *)&mask->key + range->start;

        mask->range = *range;
        memset(m, val, range_n_bytes(range));
}