// SPDX-License-Identifier: GPL-2.0-only

  /*

   * Copyright (c) 2007-2017 Nicira, Inc.

   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/skbuff.h>
  #include <linux/in.h>
  #include <linux/ip.h>
  #include <linux/openvswitch.h>

  #include <linux/sctp.h>

  #include <linux/tcp.h>
  #include <linux/udp.h>
  #include <linux/in6.h>
  #include <linux/if_arp.h>
  #include <linux/if_vlan.h>

  #include <net/dst.h>

  #include <net/ip.h>

  #include <net/ipv6.h>

  #include <net/ip6_fib.h>

  #include <net/checksum.h>
  #include <net/dsfield.h>

  #include <net/mpls.h>

  #include <net/sctp/checksum.h>

  
  #include "datapath.h"

  #include "flow.h"

  #include "conntrack.h"

  #include "vport.h"

  #include "flow_netlink.h"

  struct deferred_action {
  	struct sk_buff *skb;
  	const struct nlattr *actions;

  	int actions_len;

  
  	/* Store pkt_key clone when creating deferred action. */
  	struct sw_flow_key pkt_key;
  };

  #define MAX_L2_LEN	(VLAN_ETH_HLEN + 3 * MPLS_HLEN)
  struct ovs_frag_data {
  	unsigned long dst;
  	struct vport *vport;
  	struct ovs_skb_cb cb;
  	__be16 inner_protocol;

  	u16 network_offset;	/* valid only for MPLS */
  	u16 vlan_tci;

  	__be16 vlan_proto;
  	unsigned int l2_len;

  	u8 mac_proto;

  	u8 l2_data[MAX_L2_LEN];
  };
  
  static DEFINE_PER_CPU(struct ovs_frag_data, ovs_frag_data_storage);

  #define DEFERRED_ACTION_FIFO_SIZE 10

  #define OVS_RECURSION_LIMIT 5
  #define OVS_DEFERRED_ACTION_THRESHOLD (OVS_RECURSION_LIMIT - 2)

  struct action_fifo {
  	int head;
  	int tail;
  	/* Deferred action fifo queue storage. */
  	struct deferred_action fifo[DEFERRED_ACTION_FIFO_SIZE];
  };

  struct action_flow_keys {

  	struct sw_flow_key key[OVS_DEFERRED_ACTION_THRESHOLD];
  };

  static struct action_fifo __percpu *action_fifos;

  static struct action_flow_keys __percpu *flow_keys;

  static DEFINE_PER_CPU(int, exec_actions_level);

  /* Make a clone of the 'key', using the pre-allocated percpu 'flow_keys'
   * space. Return NULL if out of key spaces.
   */
  static struct sw_flow_key *clone_key(const struct sw_flow_key *key_)
  {
  	struct action_flow_keys *keys = this_cpu_ptr(flow_keys);
  	int level = this_cpu_read(exec_actions_level);
  	struct sw_flow_key *key = NULL;
  
  	if (level <= OVS_DEFERRED_ACTION_THRESHOLD) {
  		key = &keys->key[level - 1];
  		*key = *key_;
  	}
  
  	return key;
  }

  static void action_fifo_init(struct action_fifo *fifo)
  {
  	fifo->head = 0;
  	fifo->tail = 0;
  }

  static bool action_fifo_is_empty(const struct action_fifo *fifo)

  {
  	return (fifo->head == fifo->tail);
  }
  
  static struct deferred_action *action_fifo_get(struct action_fifo *fifo)
  {
  	if (action_fifo_is_empty(fifo))
  		return NULL;
  
  	return &fifo->fifo[fifo->tail++];
  }
  
  static struct deferred_action *action_fifo_put(struct action_fifo *fifo)
  {
  	if (fifo->head >= DEFERRED_ACTION_FIFO_SIZE - 1)
  		return NULL;
  
  	return &fifo->fifo[fifo->head++];
  }
  
  /* Return true if fifo is not full */
  static struct deferred_action *add_deferred_actions(struct sk_buff *skb,

  				    const struct sw_flow_key *key,
  				    const struct nlattr *actions,
  				    const int actions_len)

  {
  	struct action_fifo *fifo;
  	struct deferred_action *da;
  
  	fifo = this_cpu_ptr(action_fifos);
  	da = action_fifo_put(fifo);
  	if (da) {
  		da->skb = skb;

  		da->actions = actions;
  		da->actions_len = actions_len;

  		da->pkt_key = *key;
  	}
  
  	return da;
  }

  static void invalidate_flow_key(struct sw_flow_key *key)
  {

  	key->mac_proto |= SW_FLOW_KEY_INVALID;

  }
  
  static bool is_flow_key_valid(const struct sw_flow_key *key)
  {

  	return !(key->mac_proto & SW_FLOW_KEY_INVALID);

  }

  static int clone_execute(struct datapath *dp, struct sk_buff *skb,
  			 struct sw_flow_key *key,
  			 u32 recirc_id,
  			 const struct nlattr *actions, int len,
  			 bool last, bool clone_flow_key);

  static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
  			      struct sw_flow_key *key,
  			      const struct nlattr *attr, int len);

  static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,

  		     __be32 mpls_lse, __be16 mpls_ethertype, __u16 mac_len)

  {

  	int err;

  	err = skb_mpls_push(skb, mpls_lse, mpls_ethertype, mac_len, !!mac_len);

  	if (err)
  		return err;

  	if (!mac_len)
  		key->mac_proto = MAC_PROTO_NONE;

  	invalidate_flow_key(key);

  	return 0;
  }

  static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
  		    const __be16 ethertype)

  {

  	int err;

  	err = skb_mpls_pop(skb, ethertype, skb->mac_len,
  			   ovs_key_mac_proto(key) == MAC_PROTO_ETHERNET);

  	if (err)

  		return err;

  	if (ethertype == htons(ETH_P_TEB))
  		key->mac_proto = MAC_PROTO_ETHERNET;

  	invalidate_flow_key(key);

  	return 0;
  }

  static int set_mpls(struct sk_buff *skb, struct sw_flow_key *flow_key,
  		    const __be32 *mpls_lse, const __be32 *mask)

  {

  	struct mpls_shim_hdr *stack;

  	__be32 lse;

  	int err;

  	if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN))
  		return -ENOMEM;

  	stack = mpls_hdr(skb);
  	lse = OVS_MASKED(stack->label_stack_entry, *mpls_lse, *mask);

  	err = skb_mpls_update_lse(skb, lse);
  	if (err)
  		return err;

  	flow_key->mpls.lse[0] = lse;

  	return 0;
  }

  static int pop_vlan(struct sk_buff *skb, struct sw_flow_key *key)

  {

  	int err;

  	err = skb_vlan_pop(skb);

  	if (skb_vlan_tag_present(skb)) {

  		invalidate_flow_key(key);

  	} else {
  		key->eth.vlan.tci = 0;
  		key->eth.vlan.tpid = 0;
  	}

  	return err;

  }

  static int push_vlan(struct sk_buff *skb, struct sw_flow_key *key,
  		     const struct ovs_action_push_vlan *vlan)

  {

  	if (skb_vlan_tag_present(skb)) {

  		invalidate_flow_key(key);

  	} else {
  		key->eth.vlan.tci = vlan->vlan_tci;
  		key->eth.vlan.tpid = vlan->vlan_tpid;
  	}

  	return skb_vlan_push(skb, vlan->vlan_tpid,

  			     ntohs(vlan->vlan_tci) & ~VLAN_CFI_MASK);

  }

  /* 'src' is already properly masked. */
  static void ether_addr_copy_masked(u8 *dst_, const u8 *src_, const u8 *mask_)
  {
  	u16 *dst = (u16 *)dst_;
  	const u16 *src = (const u16 *)src_;
  	const u16 *mask = (const u16 *)mask_;

  	OVS_SET_MASKED(dst[0], src[0], mask[0]);
  	OVS_SET_MASKED(dst[1], src[1], mask[1]);
  	OVS_SET_MASKED(dst[2], src[2], mask[2]);

  }
  
  static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *flow_key,
  			const struct ovs_key_ethernet *key,
  			const struct ovs_key_ethernet *mask)

  {
  	int err;

  	err = skb_ensure_writable(skb, ETH_HLEN);

  	if (unlikely(err))
  		return err;

  	skb_postpull_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);

  	ether_addr_copy_masked(eth_hdr(skb)->h_source, key->eth_src,
  			       mask->eth_src);
  	ether_addr_copy_masked(eth_hdr(skb)->h_dest, key->eth_dst,
  			       mask->eth_dst);

  	skb_postpush_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);

  	ether_addr_copy(flow_key->eth.src, eth_hdr(skb)->h_source);
  	ether_addr_copy(flow_key->eth.dst, eth_hdr(skb)->h_dest);

  	return 0;
  }

  /* pop_eth does not support VLAN packets as this action is never called
   * for them.
   */
  static int pop_eth(struct sk_buff *skb, struct sw_flow_key *key)
  {

  	int err;
  
  	err = skb_eth_pop(skb);
  	if (err)
  		return err;

  
  	/* safe right before invalidate_flow_key */
  	key->mac_proto = MAC_PROTO_NONE;
  	invalidate_flow_key(key);
  	return 0;
  }
  
  static int push_eth(struct sk_buff *skb, struct sw_flow_key *key,
  		    const struct ovs_action_push_eth *ethh)
  {

  	int err;

  	err = skb_eth_push(skb, ethh->addresses.eth_dst,
  			   ethh->addresses.eth_src);
  	if (err)
  		return err;

  
  	/* safe right before invalidate_flow_key */
  	key->mac_proto = MAC_PROTO_ETHERNET;
  	invalidate_flow_key(key);
  	return 0;
  }

  static int push_nsh(struct sk_buff *skb, struct sw_flow_key *key,
  		    const struct nshhdr *nh)
  {
  	int err;
  
  	err = nsh_push(skb, nh);
  	if (err)
  		return err;
  
  	/* safe right before invalidate_flow_key */
  	key->mac_proto = MAC_PROTO_NONE;
  	invalidate_flow_key(key);
  	return 0;
  }
  
  static int pop_nsh(struct sk_buff *skb, struct sw_flow_key *key)
  {
  	int err;
  
  	err = nsh_pop(skb);
  	if (err)
  		return err;
  
  	/* safe right before invalidate_flow_key */
  	if (skb->protocol == htons(ETH_P_TEB))
  		key->mac_proto = MAC_PROTO_ETHERNET;
  	else
  		key->mac_proto = MAC_PROTO_NONE;
  	invalidate_flow_key(key);
  	return 0;
  }

  static void update_ip_l4_checksum(struct sk_buff *skb, struct iphdr *nh,
  				  __be32 addr, __be32 new_addr)

  {
  	int transport_len = skb->len - skb_transport_offset(skb);

  	if (nh->frag_off & htons(IP_OFFSET))
  		return;

  	if (nh->protocol == IPPROTO_TCP) {
  		if (likely(transport_len >= sizeof(struct tcphdr)))
  			inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,

  						 addr, new_addr, true);

  	} else if (nh->protocol == IPPROTO_UDP) {

  		if (likely(transport_len >= sizeof(struct udphdr))) {
  			struct udphdr *uh = udp_hdr(skb);
  
  			if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
  				inet_proto_csum_replace4(&uh->check, skb,

  							 addr, new_addr, true);

  				if (!uh->check)
  					uh->check = CSUM_MANGLED_0;
  			}
  		}

  	}

  }

  static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
  			__be32 *addr, __be32 new_addr)
  {
  	update_ip_l4_checksum(skb, nh, *addr, new_addr);

  	csum_replace4(&nh->check, *addr, new_addr);

  	skb_clear_hash(skb);

  	*addr = new_addr;
  }

  static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
  				 __be32 addr[4], const __be32 new_addr[4])
  {
  	int transport_len = skb->len - skb_transport_offset(skb);

  	if (l4_proto == NEXTHDR_TCP) {

  		if (likely(transport_len >= sizeof(struct tcphdr)))
  			inet_proto_csum_replace16(&tcp_hdr(skb)->check, skb,

  						  addr, new_addr, true);

  	} else if (l4_proto == NEXTHDR_UDP) {

  		if (likely(transport_len >= sizeof(struct udphdr))) {
  			struct udphdr *uh = udp_hdr(skb);
  
  			if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
  				inet_proto_csum_replace16(&uh->check, skb,

  							  addr, new_addr, true);

  				if (!uh->check)
  					uh->check = CSUM_MANGLED_0;
  			}
  		}

  	} else if (l4_proto == NEXTHDR_ICMP) {
  		if (likely(transport_len >= sizeof(struct icmp6hdr)))
  			inet_proto_csum_replace16(&icmp6_hdr(skb)->icmp6_cksum,

  						  skb, addr, new_addr, true);

  	}
  }

  static void mask_ipv6_addr(const __be32 old[4], const __be32 addr[4],
  			   const __be32 mask[4], __be32 masked[4])
  {

  	masked[0] = OVS_MASKED(old[0], addr[0], mask[0]);
  	masked[1] = OVS_MASKED(old[1], addr[1], mask[1]);
  	masked[2] = OVS_MASKED(old[2], addr[2], mask[2]);
  	masked[3] = OVS_MASKED(old[3], addr[3], mask[3]);

  }

  static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
  			  __be32 addr[4], const __be32 new_addr[4],
  			  bool recalculate_csum)
  {
  	if (recalculate_csum)
  		update_ipv6_checksum(skb, l4_proto, addr, new_addr);

  	skb_clear_hash(skb);

  	memcpy(addr, new_addr, sizeof(__be32[4]));
  }

  static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl, u32 mask)

  {

  	/* Bits 21-24 are always unmasked, so this retains their values. */

  	OVS_SET_MASKED(nh->flow_lbl[0], (u8)(fl >> 16), (u8)(mask >> 16));
  	OVS_SET_MASKED(nh->flow_lbl[1], (u8)(fl >> 8), (u8)(mask >> 8));
  	OVS_SET_MASKED(nh->flow_lbl[2], (u8)fl, (u8)mask);

  }

  static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl,
  		       u8 mask)

  {

  	new_ttl = OVS_MASKED(nh->ttl, new_ttl, mask);

  	csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
  	nh->ttl = new_ttl;
  }

  static int set_ipv4(struct sk_buff *skb, struct sw_flow_key *flow_key,
  		    const struct ovs_key_ipv4 *key,
  		    const struct ovs_key_ipv4 *mask)

  {
  	struct iphdr *nh;

  	__be32 new_addr;

  	int err;

  	err = skb_ensure_writable(skb, skb_network_offset(skb) +
  				  sizeof(struct iphdr));

  	if (unlikely(err))
  		return err;
  
  	nh = ip_hdr(skb);

  	/* Setting an IP addresses is typically only a side effect of
  	 * matching on them in the current userspace implementation, so it
  	 * makes sense to check if the value actually changed.
  	 */
  	if (mask->ipv4_src) {

  		new_addr = OVS_MASKED(nh->saddr, key->ipv4_src, mask->ipv4_src);

  		if (unlikely(new_addr != nh->saddr)) {
  			set_ip_addr(skb, nh, &nh->saddr, new_addr);
  			flow_key->ipv4.addr.src = new_addr;
  		}

  	}

  	if (mask->ipv4_dst) {

  		new_addr = OVS_MASKED(nh->daddr, key->ipv4_dst, mask->ipv4_dst);

  		if (unlikely(new_addr != nh->daddr)) {
  			set_ip_addr(skb, nh, &nh->daddr, new_addr);
  			flow_key->ipv4.addr.dst = new_addr;
  		}

  	}

  	if (mask->ipv4_tos) {
  		ipv4_change_dsfield(nh, ~mask->ipv4_tos, key->ipv4_tos);
  		flow_key->ip.tos = nh->tos;
  	}
  	if (mask->ipv4_ttl) {
  		set_ip_ttl(skb, nh, key->ipv4_ttl, mask->ipv4_ttl);
  		flow_key->ip.ttl = nh->ttl;

  	}

  
  	return 0;
  }

  static bool is_ipv6_mask_nonzero(const __be32 addr[4])
  {
  	return !!(addr[0] | addr[1] | addr[2] | addr[3]);
  }
  
  static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *flow_key,
  		    const struct ovs_key_ipv6 *key,
  		    const struct ovs_key_ipv6 *mask)

  {
  	struct ipv6hdr *nh;
  	int err;

  	err = skb_ensure_writable(skb, skb_network_offset(skb) +
  				  sizeof(struct ipv6hdr));

  	if (unlikely(err))
  		return err;
  
  	nh = ipv6_hdr(skb);

  	/* Setting an IP addresses is typically only a side effect of
  	 * matching on them in the current userspace implementation, so it
  	 * makes sense to check if the value actually changed.
  	 */
  	if (is_ipv6_mask_nonzero(mask->ipv6_src)) {
  		__be32 *saddr = (__be32 *)&nh->saddr;
  		__be32 masked[4];
  
  		mask_ipv6_addr(saddr, key->ipv6_src, mask->ipv6_src, masked);
  
  		if (unlikely(memcmp(saddr, masked, sizeof(masked)))) {

  			set_ipv6_addr(skb, flow_key->ip.proto, saddr, masked,

  				      true);
  			memcpy(&flow_key->ipv6.addr.src, masked,
  			       sizeof(flow_key->ipv6.addr.src));
  		}
  	}
  	if (is_ipv6_mask_nonzero(mask->ipv6_dst)) {

  		unsigned int offset = 0;
  		int flags = IP6_FH_F_SKIP_RH;
  		bool recalc_csum = true;

  		__be32 *daddr = (__be32 *)&nh->daddr;
  		__be32 masked[4];
  
  		mask_ipv6_addr(daddr, key->ipv6_dst, mask->ipv6_dst, masked);
  
  		if (unlikely(memcmp(daddr, masked, sizeof(masked)))) {
  			if (ipv6_ext_hdr(nh->nexthdr))
  				recalc_csum = (ipv6_find_hdr(skb, &offset,
  							     NEXTHDR_ROUTING,
  							     NULL, &flags)
  					       != NEXTHDR_ROUTING);

  			set_ipv6_addr(skb, flow_key->ip.proto, daddr, masked,

  				      recalc_csum);
  			memcpy(&flow_key->ipv6.addr.dst, masked,
  			       sizeof(flow_key->ipv6.addr.dst));
  		}
  	}
  	if (mask->ipv6_tclass) {
  		ipv6_change_dsfield(nh, ~mask->ipv6_tclass, key->ipv6_tclass);
  		flow_key->ip.tos = ipv6_get_dsfield(nh);
  	}
  	if (mask->ipv6_label) {
  		set_ipv6_fl(nh, ntohl(key->ipv6_label),
  			    ntohl(mask->ipv6_label));
  		flow_key->ipv6.label =
  		    *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
  	}
  	if (mask->ipv6_hlimit) {

  		OVS_SET_MASKED(nh->hop_limit, key->ipv6_hlimit,
  			       mask->ipv6_hlimit);

  		flow_key->ip.ttl = nh->hop_limit;

  	}

  	return 0;
  }

  static int set_nsh(struct sk_buff *skb, struct sw_flow_key *flow_key,
  		   const struct nlattr *a)
  {
  	struct nshhdr *nh;
  	size_t length;
  	int err;
  	u8 flags;
  	u8 ttl;
  	int i;
  
  	struct ovs_key_nsh key;
  	struct ovs_key_nsh mask;
  
  	err = nsh_key_from_nlattr(a, &key, &mask);
  	if (err)
  		return err;
  
  	/* Make sure the NSH base header is there */
  	if (!pskb_may_pull(skb, skb_network_offset(skb) + NSH_BASE_HDR_LEN))
  		return -ENOMEM;
  
  	nh = nsh_hdr(skb);
  	length = nsh_hdr_len(nh);
  
  	/* Make sure the whole NSH header is there */
  	err = skb_ensure_writable(skb, skb_network_offset(skb) +
  				       length);
  	if (unlikely(err))
  		return err;
  
  	nh = nsh_hdr(skb);
  	skb_postpull_rcsum(skb, nh, length);
  	flags = nsh_get_flags(nh);
  	flags = OVS_MASKED(flags, key.base.flags, mask.base.flags);
  	flow_key->nsh.base.flags = flags;
  	ttl = nsh_get_ttl(nh);
  	ttl = OVS_MASKED(ttl, key.base.ttl, mask.base.ttl);
  	flow_key->nsh.base.ttl = ttl;
  	nsh_set_flags_and_ttl(nh, flags, ttl);
  	nh->path_hdr = OVS_MASKED(nh->path_hdr, key.base.path_hdr,
  				  mask.base.path_hdr);
  	flow_key->nsh.base.path_hdr = nh->path_hdr;
  	switch (nh->mdtype) {
  	case NSH_M_TYPE1:
  		for (i = 0; i < NSH_MD1_CONTEXT_SIZE; i++) {
  			nh->md1.context[i] =
  			    OVS_MASKED(nh->md1.context[i], key.context[i],
  				       mask.context[i]);
  		}
  		memcpy(flow_key->nsh.context, nh->md1.context,
  		       sizeof(nh->md1.context));
  		break;
  	case NSH_M_TYPE2:
  		memset(flow_key->nsh.context, 0,
  		       sizeof(flow_key->nsh.context));
  		break;
  	default:
  		return -EINVAL;
  	}
  	skb_postpush_rcsum(skb, nh, length);
  	return 0;
  }

  /* Must follow skb_ensure_writable() since that can move the skb data. */

  static void set_tp_port(struct sk_buff *skb, __be16 *port,

  			__be16 new_port, __sum16 *check)

  {

  	inet_proto_csum_replace2(check, skb, *port, new_port, false);

  	*port = new_port;

  }

  static int set_udp(struct sk_buff *skb, struct sw_flow_key *flow_key,
  		   const struct ovs_key_udp *key,
  		   const struct ovs_key_udp *mask)

  {
  	struct udphdr *uh;

  	__be16 src, dst;

  	int err;

  	err = skb_ensure_writable(skb, skb_transport_offset(skb) +
  				  sizeof(struct udphdr));

  	if (unlikely(err))
  		return err;
  
  	uh = udp_hdr(skb);

  	/* Either of the masks is non-zero, so do not bother checking them. */

  	src = OVS_MASKED(uh->source, key->udp_src, mask->udp_src);
  	dst = OVS_MASKED(uh->dest, key->udp_dst, mask->udp_dst);

  	if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
  		if (likely(src != uh->source)) {
  			set_tp_port(skb, &uh->source, src, &uh->check);
  			flow_key->tp.src = src;
  		}
  		if (likely(dst != uh->dest)) {
  			set_tp_port(skb, &uh->dest, dst, &uh->check);
  			flow_key->tp.dst = dst;
  		}
  
  		if (unlikely(!uh->check))
  			uh->check = CSUM_MANGLED_0;
  	} else {
  		uh->source = src;
  		uh->dest = dst;
  		flow_key->tp.src = src;
  		flow_key->tp.dst = dst;

  	}

  	skb_clear_hash(skb);

  	return 0;
  }

  static int set_tcp(struct sk_buff *skb, struct sw_flow_key *flow_key,
  		   const struct ovs_key_tcp *key,
  		   const struct ovs_key_tcp *mask)

  {
  	struct tcphdr *th;

  	__be16 src, dst;

  	int err;

  	err = skb_ensure_writable(skb, skb_transport_offset(skb) +
  				  sizeof(struct tcphdr));

  	if (unlikely(err))
  		return err;
  
  	th = tcp_hdr(skb);

  	src = OVS_MASKED(th->source, key->tcp_src, mask->tcp_src);

  	if (likely(src != th->source)) {
  		set_tp_port(skb, &th->source, src, &th->check);
  		flow_key->tp.src = src;

  	}

  	dst = OVS_MASKED(th->dest, key->tcp_dst, mask->tcp_dst);

  	if (likely(dst != th->dest)) {
  		set_tp_port(skb, &th->dest, dst, &th->check);
  		flow_key->tp.dst = dst;

  	}

  	skb_clear_hash(skb);

  
  	return 0;
  }

  static int set_sctp(struct sk_buff *skb, struct sw_flow_key *flow_key,
  		    const struct ovs_key_sctp *key,
  		    const struct ovs_key_sctp *mask)

  {

  	unsigned int sctphoff = skb_transport_offset(skb);

  	struct sctphdr *sh;

  	__le32 old_correct_csum, new_csum, old_csum;

  	int err;

  	err = skb_ensure_writable(skb, sctphoff + sizeof(struct sctphdr));

  	if (unlikely(err))
  		return err;
  
  	sh = sctp_hdr(skb);

  	old_csum = sh->checksum;
  	old_correct_csum = sctp_compute_cksum(skb, sctphoff);

  	sh->source = OVS_MASKED(sh->source, key->sctp_src, mask->sctp_src);
  	sh->dest = OVS_MASKED(sh->dest, key->sctp_dst, mask->sctp_dst);

  	new_csum = sctp_compute_cksum(skb, sctphoff);

  	/* Carry any checksum errors through. */
  	sh->checksum = old_csum ^ old_correct_csum ^ new_csum;

  	skb_clear_hash(skb);
  	flow_key->tp.src = sh->source;
  	flow_key->tp.dst = sh->dest;

  
  	return 0;
  }

  static int ovs_vport_output(struct net *net, struct sock *sk,
  			    struct sk_buff *skb)

  {
  	struct ovs_frag_data *data = this_cpu_ptr(&ovs_frag_data_storage);
  	struct vport *vport = data->vport;
  
  	if (skb_cow_head(skb, data->l2_len) < 0) {
  		kfree_skb(skb);
  		return -ENOMEM;
  	}
  
  	__skb_dst_copy(skb, data->dst);
  	*OVS_CB(skb) = data->cb;
  	skb->inner_protocol = data->inner_protocol;

  	if (data->vlan_tci & VLAN_CFI_MASK)
  		__vlan_hwaccel_put_tag(skb, data->vlan_proto, data->vlan_tci & ~VLAN_CFI_MASK);
  	else
  		__vlan_hwaccel_clear_tag(skb);

  
  	/* Reconstruct the MAC header.  */
  	skb_push(skb, data->l2_len);
  	memcpy(skb->data, &data->l2_data, data->l2_len);

  	skb_postpush_rcsum(skb, skb->data, data->l2_len);

  	skb_reset_mac_header(skb);

  	if (eth_p_mpls(skb->protocol)) {
  		skb->inner_network_header = skb->network_header;
  		skb_set_network_header(skb, data->network_offset);
  		skb_reset_mac_len(skb);
  	}

  	ovs_vport_send(vport, skb, data->mac_proto);

  	return 0;
  }
  
  static unsigned int
  ovs_dst_get_mtu(const struct dst_entry *dst)
  {
  	return dst->dev->mtu;
  }
  
  static struct dst_ops ovs_dst_ops = {
  	.family = AF_UNSPEC,
  	.mtu = ovs_dst_get_mtu,
  };
  
  /* prepare_frag() is called once per (larger-than-MTU) frame; its inverse is
   * ovs_vport_output(), which is called once per fragmented packet.
   */

  static void prepare_frag(struct vport *vport, struct sk_buff *skb,

  			 u16 orig_network_offset, u8 mac_proto)

  {
  	unsigned int hlen = skb_network_offset(skb);
  	struct ovs_frag_data *data;
  
  	data = this_cpu_ptr(&ovs_frag_data_storage);
  	data->dst = skb->_skb_refdst;
  	data->vport = vport;
  	data->cb = *OVS_CB(skb);
  	data->inner_protocol = skb->inner_protocol;

  	data->network_offset = orig_network_offset;

  	if (skb_vlan_tag_present(skb))
  		data->vlan_tci = skb_vlan_tag_get(skb) | VLAN_CFI_MASK;
  	else
  		data->vlan_tci = 0;

  	data->vlan_proto = skb->vlan_proto;

  	data->mac_proto = mac_proto;

  	data->l2_len = hlen;
  	memcpy(&data->l2_data, skb->data, hlen);
  
  	memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
  	skb_pull(skb, hlen);
  }

  static void ovs_fragment(struct net *net, struct vport *vport,

  			 struct sk_buff *skb, u16 mru,
  			 struct sw_flow_key *key)

  {

  	u16 orig_network_offset = 0;
  
  	if (eth_p_mpls(skb->protocol)) {
  		orig_network_offset = skb_network_offset(skb);
  		skb->network_header = skb->inner_network_header;
  	}

  	if (skb_network_offset(skb) > MAX_L2_LEN) {
  		OVS_NLERR(1, "L2 header too long to fragment");

  		goto err;

  	}

  	if (key->eth.type == htons(ETH_P_IP)) {

  		struct dst_entry ovs_dst;
  		unsigned long orig_dst;

  		prepare_frag(vport, skb, orig_network_offset,
  			     ovs_key_mac_proto(key));

  		dst_init(&ovs_dst, &ovs_dst_ops, NULL, 1,
  			 DST_OBSOLETE_NONE, DST_NOCOUNT);
  		ovs_dst.dev = vport->dev;
  
  		orig_dst = skb->_skb_refdst;
  		skb_dst_set_noref(skb, &ovs_dst);
  		IPCB(skb)->frag_max_size = mru;

  		ip_do_fragment(net, skb->sk, skb, ovs_vport_output);

  		refdst_drop(orig_dst);

  	} else if (key->eth.type == htons(ETH_P_IPV6)) {

  		unsigned long orig_dst;
  		struct rt6_info ovs_rt;

  		prepare_frag(vport, skb, orig_network_offset,
  			     ovs_key_mac_proto(key));

  		memset(&ovs_rt, 0, sizeof(ovs_rt));
  		dst_init(&ovs_rt.dst, &ovs_dst_ops, NULL, 1,
  			 DST_OBSOLETE_NONE, DST_NOCOUNT);
  		ovs_rt.dst.dev = vport->dev;
  
  		orig_dst = skb->_skb_refdst;
  		skb_dst_set_noref(skb, &ovs_rt.dst);
  		IP6CB(skb)->frag_max_size = mru;

  		ipv6_stub->ipv6_fragment(net, skb->sk, skb, ovs_vport_output);

  		refdst_drop(orig_dst);
  	} else {
  		WARN_ONCE(1, "Failed fragment ->%s: eth=%04x, MRU=%d, MTU=%d.",

  			  ovs_vport_name(vport), ntohs(key->eth.type), mru,

  			  vport->dev->mtu);

  		goto err;

  	}

  
  	return;
  err:
  	kfree_skb(skb);

  }
  
  static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port,
  		      struct sw_flow_key *key)

  {

  	struct vport *vport = ovs_vport_rcu(dp, out_port);

  	if (likely(vport)) {
  		u16 mru = OVS_CB(skb)->mru;

  		u32 cutlen = OVS_CB(skb)->cutlen;
  
  		if (unlikely(cutlen > 0)) {

  			if (skb->len - cutlen > ovs_mac_header_len(key))

  				pskb_trim(skb, skb->len - cutlen);
  			else

  				pskb_trim(skb, ovs_mac_header_len(key));

  		}

  		if (likely(!mru ||
  		           (skb->len <= mru + vport->dev->hard_header_len))) {

  			ovs_vport_send(vport, skb, ovs_key_mac_proto(key));

  		} else if (mru <= vport->dev->mtu) {

  			struct net *net = read_pnet(&dp->net);

  			ovs_fragment(net, vport, skb, mru, key);

  		} else {
  			kfree_skb(skb);
  		}
  	} else {

  		kfree_skb(skb);

  	}

  }
  
  static int output_userspace(struct datapath *dp, struct sk_buff *skb,

  			    struct sw_flow_key *key, const struct nlattr *attr,

  			    const struct nlattr *actions, int actions_len,
  			    uint32_t cutlen)

  {
  	struct dp_upcall_info upcall;
  	const struct nlattr *a;
  	int rem;

  	memset(&upcall, 0, sizeof(upcall));

  	upcall.cmd = OVS_PACKET_CMD_ACTION;

  	upcall.mru = OVS_CB(skb)->mru;

  
  	for (a = nla_data(attr), rem = nla_len(attr); rem > 0;

  	     a = nla_next(a, &rem)) {

  		switch (nla_type(a)) {
  		case OVS_USERSPACE_ATTR_USERDATA:
  			upcall.userdata = a;
  			break;
  
  		case OVS_USERSPACE_ATTR_PID:

  			upcall.portid = nla_get_u32(a);

  			break;

  
  		case OVS_USERSPACE_ATTR_EGRESS_TUN_PORT: {
  			/* Get out tunnel info. */
  			struct vport *vport;
  
  			vport = ovs_vport_rcu(dp, nla_get_u32(a));
  			if (vport) {
  				int err;

  				err = dev_fill_metadata_dst(vport->dev, skb);
  				if (!err)
  					upcall.egress_tun_info = skb_tunnel_info(skb);

  			}

  			break;

  		}

  		case OVS_USERSPACE_ATTR_ACTIONS: {
  			/* Include actions. */
  			upcall.actions = actions;
  			upcall.actions_len = actions_len;
  			break;
  		}

  		} /* End of switch. */

  	}

  	return ovs_dp_upcall(dp, skb, key, &upcall, cutlen);

  }

  static int dec_ttl_exception_handler(struct datapath *dp, struct sk_buff *skb,
  				     struct sw_flow_key *key,
  				     const struct nlattr *attr, bool last)
  {
  	/* The first action is always 'OVS_DEC_TTL_ATTR_ARG'. */
  	struct nlattr *dec_ttl_arg = nla_data(attr);

  
  	if (nla_len(dec_ttl_arg)) {

  		struct nlattr *actions = nla_data(dec_ttl_arg);

  
  		if (actions)

  			return clone_execute(dp, skb, key, 0, nla_data(actions),
  					     nla_len(actions), last, false);

  	}
  	consume_skb(skb);
  	return 0;
  }

  /* When 'last' is true, sample() should always consume the 'skb'.
   * Otherwise, sample() should keep 'skb' intact regardless what
   * actions are executed within sample().
   */

  static int sample(struct datapath *dp, struct sk_buff *skb,

  		  struct sw_flow_key *key, const struct nlattr *attr,

  		  bool last)

  {

  	struct nlattr *actions;
  	struct nlattr *sample_arg;

  	int rem = nla_len(attr);

  	const struct sample_arg *arg;

  	bool clone_flow_key;

  	/* The first action is always 'OVS_SAMPLE_ATTR_ARG'. */
  	sample_arg = nla_data(attr);
  	arg = nla_data(sample_arg);
  	actions = nla_next(sample_arg, &rem);

  	if ((arg->probability != U32_MAX) &&
  	    (!arg->probability || prandom_u32() > arg->probability)) {
  		if (last)
  			consume_skb(skb);
  		return 0;

  	}

  	clone_flow_key = !arg->exec;
  	return clone_execute(dp, skb, key, 0, actions, rem, last,
  			     clone_flow_key);

  }

  /* When 'last' is true, clone() should always consume the 'skb'.
   * Otherwise, clone() should keep 'skb' intact regardless what
   * actions are executed within clone().
   */
  static int clone(struct datapath *dp, struct sk_buff *skb,
  		 struct sw_flow_key *key, const struct nlattr *attr,
  		 bool last)
  {
  	struct nlattr *actions;
  	struct nlattr *clone_arg;
  	int rem = nla_len(attr);
  	bool dont_clone_flow_key;
  
  	/* The first action is always 'OVS_CLONE_ATTR_ARG'. */
  	clone_arg = nla_data(attr);
  	dont_clone_flow_key = nla_get_u32(clone_arg);
  	actions = nla_next(clone_arg, &rem);
  
  	return clone_execute(dp, skb, key, 0, actions, rem, last,
  			     !dont_clone_flow_key);
  }

  static void execute_hash(struct sk_buff *skb, struct sw_flow_key *key,
  			 const struct nlattr *attr)
  {
  	struct ovs_action_hash *hash_act = nla_data(attr);
  	u32 hash = 0;
  
  	/* OVS_HASH_ALG_L4 is the only possible hash algorithm.  */
  	hash = skb_get_hash(skb);
  	hash = jhash_1word(hash, hash_act->hash_basis);
  	if (!hash)
  		hash = 0x1;
  
  	key->ovs_flow_hash = hash;

  }

  static int execute_set_action(struct sk_buff *skb,
  			      struct sw_flow_key *flow_key,
  			      const struct nlattr *a)
  {
  	/* Only tunnel set execution is supported without a mask. */
  	if (nla_type(a) == OVS_KEY_ATTR_TUNNEL_INFO) {

  		struct ovs_tunnel_info *tun = nla_data(a);
  
  		skb_dst_drop(skb);
  		dst_hold((struct dst_entry *)tun->tun_dst);
  		skb_dst_set(skb, (struct dst_entry *)tun->tun_dst);

  		return 0;
  	}
  
  	return -EINVAL;
  }
  
  /* Mask is at the midpoint of the data. */
  #define get_mask(a, type) ((const type)nla_data(a) + 1)
  
  static int execute_masked_set_action(struct sk_buff *skb,
  				     struct sw_flow_key *flow_key,
  				     const struct nlattr *a)

  {
  	int err = 0;

  	switch (nla_type(a)) {

  	case OVS_KEY_ATTR_PRIORITY:

  		OVS_SET_MASKED(skb->priority, nla_get_u32(a),
  			       *get_mask(a, u32 *));

  		flow_key->phy.priority = skb->priority;

  		break;

  	case OVS_KEY_ATTR_SKB_MARK:

  		OVS_SET_MASKED(skb->mark, nla_get_u32(a), *get_mask(a, u32 *));

  		flow_key->phy.skb_mark = skb->mark;

  		break;

  	case OVS_KEY_ATTR_TUNNEL_INFO:

  		/* Masked data not supported for tunnel. */
  		err = -EINVAL;

  		break;

  	case OVS_KEY_ATTR_ETHERNET:

  		err = set_eth_addr(skb, flow_key, nla_data(a),
  				   get_mask(a, struct ovs_key_ethernet *));

  		break;

  	case OVS_KEY_ATTR_NSH:
  		err = set_nsh(skb, flow_key, a);
  		break;

  	case OVS_KEY_ATTR_IPV4:

  		err = set_ipv4(skb, flow_key, nla_data(a),
  			       get_mask(a, struct ovs_key_ipv4 *));

  		break;

  	case OVS_KEY_ATTR_IPV6:

  		err = set_ipv6(skb, flow_key, nla_data(a),
  			       get_mask(a, struct ovs_key_ipv6 *));

  		break;

  	case OVS_KEY_ATTR_TCP:

  		err = set_tcp(skb, flow_key, nla_data(a),
  			      get_mask(a, struct ovs_key_tcp *));

  		break;
  
  	case OVS_KEY_ATTR_UDP:

  		err = set_udp(skb, flow_key, nla_data(a),
  			      get_mask(a, struct ovs_key_udp *));

  		break;

  
  	case OVS_KEY_ATTR_SCTP:

  		err = set_sctp(skb, flow_key, nla_data(a),
  			       get_mask(a, struct ovs_key_sctp *));

  		break;

  
  	case OVS_KEY_ATTR_MPLS:

  		err = set_mpls(skb, flow_key, nla_data(a), get_mask(a,
  								    __be32 *));

  		break;

  
  	case OVS_KEY_ATTR_CT_STATE:
  	case OVS_KEY_ATTR_CT_ZONE:

  	case OVS_KEY_ATTR_CT_MARK:

  	case OVS_KEY_ATTR_CT_LABELS:

  	case OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV4:
  	case OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV6:

  		err = -EINVAL;
  		break;

  	}
  
  	return err;
  }

  static int execute_recirc(struct datapath *dp, struct sk_buff *skb,
  			  struct sw_flow_key *key,

  			  const struct nlattr *a, bool last)

  {

  	u32 recirc_id;

  	if (!is_flow_key_valid(key)) {
  		int err;
  
  		err = ovs_flow_key_update(skb, key);
  		if (err)
  			return err;
  	}
  	BUG_ON(!is_flow_key_valid(key));

  	recirc_id = nla_get_u32(a);
  	return clone_execute(dp, skb, key, recirc_id, NULL, 0, last, true);

  }

  static int execute_check_pkt_len(struct datapath *dp, struct sk_buff *skb,
  				 struct sw_flow_key *key,
  				 const struct nlattr *attr, bool last)
  {

  	struct ovs_skb_cb *ovs_cb = OVS_CB(skb);

  	const struct nlattr *actions, *cpl_arg;

  	int len, max_len, rem = nla_len(attr);

  	const struct check_pkt_len_arg *arg;

  	bool clone_flow_key;
  
  	/* The first netlink attribute in 'attr' is always
  	 * 'OVS_CHECK_PKT_LEN_ATTR_ARG'.
  	 */
  	cpl_arg = nla_data(attr);
  	arg = nla_data(cpl_arg);

  	len = ovs_cb->mru ? ovs_cb->mru + skb->mac_len : skb->len;
  	max_len = arg->pkt_len;
  
  	if ((skb_is_gso(skb) && skb_gso_validate_mac_len(skb, max_len)) ||
  	    len <= max_len) {

  		/* Second netlink attribute in 'attr' is always
  		 * 'OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_LESS_EQUAL'.
  		 */
  		actions = nla_next(cpl_arg, &rem);
  		clone_flow_key = !arg->exec_for_lesser_equal;
  	} else {
  		/* Third netlink attribute in 'attr' is always
  		 * 'OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_GREATER'.
  		 */
  		actions = nla_next(cpl_arg, &rem);
  		actions = nla_next(actions, &rem);
  		clone_flow_key = !arg->exec_for_greater;
  	}
  
  	return clone_execute(dp, skb, key, 0, nla_data(actions),
  			     nla_len(actions), last, clone_flow_key);
  }

  static int execute_dec_ttl(struct sk_buff *skb, struct sw_flow_key *key)
  {
  	int err;
  
  	if (skb->protocol == htons(ETH_P_IPV6)) {
  		struct ipv6hdr *nh;
  
  		err = skb_ensure_writable(skb, skb_network_offset(skb) +
  					  sizeof(*nh));
  		if (unlikely(err))
  			return err;
  
  		nh = ipv6_hdr(skb);
  
  		if (nh->hop_limit <= 1)
  			return -EHOSTUNREACH;
  
  		key->ip.ttl = --nh->hop_limit;
  	} else {
  		struct iphdr *nh;
  		u8 old_ttl;
  
  		err = skb_ensure_writable(skb, skb_network_offset(skb) +
  					  sizeof(*nh));
  		if (unlikely(err))
  			return err;
  
  		nh = ip_hdr(skb);
  		if (nh->ttl <= 1)
  			return -EHOSTUNREACH;
  
  		old_ttl = nh->ttl--;
  		csum_replace2(&nh->check, htons(old_ttl << 8),
  			      htons(nh->ttl << 8));
  		key->ip.ttl = nh->ttl;
  	}
  	return 0;
  }

  /* Execute a list of actions against 'skb'. */
  static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,

  			      struct sw_flow_key *key,

  			      const struct nlattr *attr, int len)

  {

  	const struct nlattr *a;
  	int rem;
  
  	for (a = attr, rem = len; rem > 0;
  	     a = nla_next(a, &rem)) {
  		int err = 0;

  		switch (nla_type(a)) {
  		case OVS_ACTION_ATTR_OUTPUT: {
  			int port = nla_get_u32(a);
  			struct sk_buff *clone;
  
  			/* Every output action needs a separate clone
  			 * of 'skb', In case the output action is the
  			 * last action, cloning can be avoided.
  			 */
  			if (nla_is_last(a, rem)) {
  				do_output(dp, skb, port, key);
  				/* 'skb' has been used for output.
  				 */
  				return 0;
  			}

  			clone = skb_clone(skb, GFP_ATOMIC);
  			if (clone)
  				do_output(dp, clone, port, key);

  			OVS_CB(skb)->cutlen = 0;

  			break;

  		}

  		case OVS_ACTION_ATTR_TRUNC: {
  			struct ovs_action_trunc *trunc = nla_data(a);
  
  			if (skb->len > trunc->max_len)
  				OVS_CB(skb)->cutlen = skb->len - trunc->max_len;
  			break;
  		}

  		case OVS_ACTION_ATTR_USERSPACE:

  			output_userspace(dp, skb, key, a, attr,
  						     len, OVS_CB(skb)->cutlen);
  			OVS_CB(skb)->cutlen = 0;

  			break;

  		case OVS_ACTION_ATTR_HASH:
  			execute_hash(skb, key, a);
  			break;

  		case OVS_ACTION_ATTR_PUSH_MPLS: {
  			struct ovs_action_push_mpls *mpls = nla_data(a);
  
  			err = push_mpls(skb, key, mpls->mpls_lse,
  					mpls->mpls_ethertype, skb->mac_len);

  			break;

  		}
  		case OVS_ACTION_ATTR_ADD_MPLS: {
  			struct ovs_action_add_mpls *mpls = nla_data(a);
  			__u16 mac_len = 0;
  
  			if (mpls->tun_flags & OVS_MPLS_L3_TUNNEL_FLAG_MASK)
  				mac_len = skb->mac_len;

  			err = push_mpls(skb, key, mpls->mpls_lse,
  					mpls->mpls_ethertype, mac_len);
  			break;
  		}

  		case OVS_ACTION_ATTR_POP_MPLS:

  			err = pop_mpls(skb, key, nla_get_be16(a));

  			break;

  		case OVS_ACTION_ATTR_PUSH_VLAN:

  			err = push_vlan(skb, key, nla_data(a));

  			break;
  
  		case OVS_ACTION_ATTR_POP_VLAN:

  			err = pop_vlan(skb, key);

  			break;

  		case OVS_ACTION_ATTR_RECIRC: {
  			bool last = nla_is_last(a, rem);
  
  			err = execute_recirc(dp, skb, key, a, last);
  			if (last) {

  				/* If this is the last action, the skb has
  				 * been consumed or freed.
  				 * Return immediately.
  				 */
  				return err;
  			}
  			break;

  		}

  		case OVS_ACTION_ATTR_SET:

  			err = execute_set_action(skb, key, nla_data(a));

  			break;

  		case OVS_ACTION_ATTR_SET_MASKED:
  		case OVS_ACTION_ATTR_SET_TO_MASKED:
  			err = execute_masked_set_action(skb, key, nla_data(a));
  			break;

  		case OVS_ACTION_ATTR_SAMPLE: {
  			bool last = nla_is_last(a, rem);
  
  			err = sample(dp, skb, key, a, last);
  			if (last)
  				return err;

  			break;

  		}

  
  		case OVS_ACTION_ATTR_CT:

  			if (!is_flow_key_valid(key)) {
  				err = ovs_flow_key_update(skb, key);
  				if (err)
  					return err;
  			}

  			err = ovs_ct_execute(ovs_dp_get_net(dp), skb, key,
  					     nla_data(a));
  
  			/* Hide stolen IP fragments from user space. */

  			if (err)
  				return err == -EINPROGRESS ? 0 : err;

  			break;

  		case OVS_ACTION_ATTR_CT_CLEAR:
  			err = ovs_ct_clear(skb, key);
  			break;

  		case OVS_ACTION_ATTR_PUSH_ETH:
  			err = push_eth(skb, key, nla_data(a));
  			break;
  
  		case OVS_ACTION_ATTR_POP_ETH:
  			err = pop_eth(skb, key);
  			break;

  
  		case OVS_ACTION_ATTR_PUSH_NSH: {
  			u8 buffer[NSH_HDR_MAX_LEN];
  			struct nshhdr *nh = (struct nshhdr *)buffer;
  
  			err = nsh_hdr_from_nlattr(nla_data(a), nh,
  						  NSH_HDR_MAX_LEN);
  			if (unlikely(err))
  				break;
  			err = push_nsh(skb, key, nh);
  			break;
  		}
  
  		case OVS_ACTION_ATTR_POP_NSH:
  			err = pop_nsh(skb, key);
  			break;

  
  		case OVS_ACTION_ATTR_METER:
  			if (ovs_meter_execute(dp, skb, key, nla_get_u32(a))) {
  				consume_skb(skb);
  				return 0;
  			}

  			break;
  
  		case OVS_ACTION_ATTR_CLONE: {
  			bool last = nla_is_last(a, rem);
  
  			err = clone(dp, skb, key, a, last);
  			if (last)
  				return err;
  
  			break;
  		}

  
  		case OVS_ACTION_ATTR_CHECK_PKT_LEN: {
  			bool last = nla_is_last(a, rem);
  
  			err = execute_check_pkt_len(dp, skb, key, a, last);
  			if (last)
  				return err;
  
  			break;
  		}

  
  		case OVS_ACTION_ATTR_DEC_TTL:
  			err = execute_dec_ttl(skb, key);
  			if (err == -EHOSTUNREACH) {
  				err = dec_ttl_exception_handler(dp, skb, key,
  								a, true);
  				return err;
  			}
  			break;

  		}
  
  		if (unlikely(err)) {
  			kfree_skb(skb);
  			return err;
  		}
  	}

  	consume_skb(skb);

  	return 0;
  }

  /* Execute the actions on the clone of the packet. The effect of the
   * execution does not affect the original 'skb' nor the original 'key'.
   *
   * The execution may be deferred in case the actions can not be executed
   * immediately.
   */
  static int clone_execute(struct datapath *dp, struct sk_buff *skb,
  			 struct sw_flow_key *key, u32 recirc_id,
  			 const struct nlattr *actions, int len,
  			 bool last, bool clone_flow_key)
  {
  	struct deferred_action *da;
  	struct sw_flow_key *clone;
  
  	skb = last ? skb : skb_clone(skb, GFP_ATOMIC);
  	if (!skb) {
  		/* Out of memory, skip this action.
  		 */
  		return 0;
  	}
  
  	/* When clone_flow_key is false, the 'key' will not be change
  	 * by the actions, then the 'key' can be used directly.
  	 * Otherwise, try to clone key from the next recursion level of
  	 * 'flow_keys'. If clone is successful, execute the actions
  	 * without deferring.
  	 */
  	clone = clone_flow_key ? clone_key(key) : key;
  	if (clone) {
  		int err = 0;
  
  		if (actions) { /* Sample action */
  			if (clone_flow_key)
  				__this_cpu_inc(exec_actions_level);
  
  			err = do_execute_actions(dp, skb, clone,
  						 actions, len);
  
  			if (clone_flow_key)
  				__this_cpu_dec(exec_actions_level);
  		} else { /* Recirc action */
  			clone->recirc_id = recirc_id;
  			ovs_dp_process_packet(skb, clone);
  		}
  		return err;
  	}
  
  	/* Out of 'flow_keys' space. Defer actions */
  	da = add_deferred_actions(skb, key, actions, len);
  	if (da) {
  		if (!actions) { /* Recirc action */
  			key = &da->pkt_key;
  			key->recirc_id = recirc_id;
  		}
  	} else {
  		/* Out of per CPU action FIFO space. Drop the 'skb' and
  		 * log an error.
  		 */
  		kfree_skb(skb);
  
  		if (net_ratelimit()) {
  			if (actions) { /* Sample action */
  				pr_warn("%s: deferred action limit reached, drop sample action
  ",
  					ovs_dp_name(dp));
  			} else {  /* Recirc action */
  				pr_warn("%s: deferred action limit reached, drop recirc action
  ",
  					ovs_dp_name(dp));
  			}
  		}
  	}
  	return 0;
  }

  static void process_deferred_actions(struct datapath *dp)
  {
  	struct action_fifo *fifo = this_cpu_ptr(action_fifos);
  
  	/* Do not touch the FIFO in case there is no deferred actions. */
  	if (action_fifo_is_empty(fifo))
  		return;
  
  	/* Finishing executing all deferred actions. */
  	do {
  		struct deferred_action *da = action_fifo_get(fifo);
  		struct sk_buff *skb = da->skb;
  		struct sw_flow_key *key = &da->pkt_key;
  		const struct nlattr *actions = da->actions;

  		int actions_len = da->actions_len;

  
  		if (actions)

  			do_execute_actions(dp, skb, key, actions, actions_len);

  		else
  			ovs_dp_process_packet(skb, key);
  	} while (!action_fifo_is_empty(fifo));
  
  	/* Reset FIFO for the next packet.  */
  	action_fifo_init(fifo);
  }

  /* Execute a list of actions against 'skb'. */

  int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb,

  			const struct sw_flow_actions *acts,
  			struct sw_flow_key *key)

  {

  	int err, level;
  
  	level = __this_cpu_inc_return(exec_actions_level);

  	if (unlikely(level > OVS_RECURSION_LIMIT)) {

  		net_crit_ratelimited("ovs: recursion limit reached on datapath %s, probable configuration error
  ",
  				     ovs_dp_name(dp));
  		kfree_skb(skb);
  		err = -ENETDOWN;
  		goto out;
  	}

  	OVS_CB(skb)->acts_origlen = acts->orig_len;

  	err = do_execute_actions(dp, skb, key,
  				 acts->actions, acts->actions_len);

  	if (level == 1)

  		process_deferred_actions(dp);

  out:
  	__this_cpu_dec(exec_actions_level);

  	return err;
  }
  
  int action_fifos_init(void)
  {
  	action_fifos = alloc_percpu(struct action_fifo);
  	if (!action_fifos)
  		return -ENOMEM;

  	flow_keys = alloc_percpu(struct action_flow_keys);
  	if (!flow_keys) {

  		free_percpu(action_fifos);
  		return -ENOMEM;
  	}

  	return 0;
  }
  
  void action_fifos_exit(void)
  {
  	free_percpu(action_fifos);

  	free_percpu(flow_keys);

  }