/*

   * 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).
  ",
  				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).
  ",
  				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).
  ",
  				  type, OVS_KEY_ATTR_MAX);

  			return -EINVAL;

  		}
  
  		if (attrs & (1 << type)) {
  			OVS_NLERR("Duplicate key attribute (type %d).
  ", 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).
  ", 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.
  ", 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).
  ",
  			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).
  ",
  				  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.
  ", rem);

  		return -EINVAL;

  	}
  
  	if (!is_mask) {
  		if (!match->key->tun_key.ipv4_dst) {
  			OVS_NLERR("IPv4 tunnel destination address is zero.
  ");
  			return -EINVAL;
  		}
  
  		if (!ttl) {
  			OVS_NLERR("IPv4 tunnel TTL not specified.
  ");
  			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.
  ");
  			else
  				OVS_NLERR("VLAN TCI does not have VLAN_TAG_PRESENT bit set.
  ");

  			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).
  ",
  					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).
  ",
  				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).
  ",
  				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).
  ",
  				  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.
  ");

  			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.
  ");
  				return -EINVAL;
  			}
  		} else {
  			OVS_NLERR("Encap attribute is set for a non-VLAN frame.
  ");
  			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.
  ");
  				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).
  ",
  						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).
  ", 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));

  }