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

  /*

   * Copyright (c) 2007-2014 Nicira, Inc.

   */

  #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/cpumask.h>

  #include <linux/if_arp.h>

  #include <linux/ip.h>
  #include <linux/ipv6.h>

  #include <linux/mpls.h>

  #include <linux/sctp.h>

  #include <linux/smp.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/mpls.h>

  #include <net/ndisc.h>

  #include <net/nsh.h>

  #include "conntrack.h"

  #include "datapath.h"
  #include "flow.h"
  #include "flow_netlink.h"

  #include "vport.h"

  u64 ovs_flow_used_time(unsigned long flow_jiffies)

  {

  	struct timespec64 cur_ts;

  	u64 cur_ms, idle_ms;

  	ktime_get_ts64(&cur_ts);

  	idle_ms = jiffies_to_msecs(jiffies - flow_jiffies);

  	cur_ms = (u64)(u32)cur_ts.tv_sec * MSEC_PER_SEC +

  		 cur_ts.tv_nsec / NSEC_PER_MSEC;

  	return cur_ms - idle_ms;

  }

  #define TCP_FLAGS_BE16(tp) (*(__be16 *)&tcp_flag_word(tp) & htons(0x0FFF))

  void ovs_flow_stats_update(struct sw_flow *flow, __be16 tcp_flags,

  			   const struct sk_buff *skb)

  {

  	struct sw_flow_stats *stats;

  	unsigned int cpu = smp_processor_id();

  	int len = skb->len + (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0);

  	stats = rcu_dereference(flow->stats[cpu]);

  	/* Check if already have CPU-specific stats. */

  	if (likely(stats)) {
  		spin_lock(&stats->lock);
  		/* Mark if we write on the pre-allocated stats. */

  		if (cpu == 0 && unlikely(flow->stats_last_writer != cpu))
  			flow->stats_last_writer = cpu;

  	} else {
  		stats = rcu_dereference(flow->stats[0]); /* Pre-allocated. */
  		spin_lock(&stats->lock);

  		/* If the current CPU is the only writer on the

  		 * pre-allocated stats keep using them.
  		 */

  		if (unlikely(flow->stats_last_writer != cpu)) {

  			/* A previous locker may have already allocated the

  			 * stats, so we need to check again.  If CPU-specific

  			 * stats were already allocated, we update the pre-
  			 * allocated stats as we have already locked them.
  			 */

  			if (likely(flow->stats_last_writer != -1) &&
  			    likely(!rcu_access_pointer(flow->stats[cpu]))) {
  				/* Try to allocate CPU-specific stats. */

  				struct sw_flow_stats *new_stats;

  
  				new_stats =
  					kmem_cache_alloc_node(flow_stats_cache,

  							      GFP_NOWAIT |
  							      __GFP_THISNODE |
  							      __GFP_NOWARN |

  							      __GFP_NOMEMALLOC,

  							      numa_node_id());

  				if (likely(new_stats)) {
  					new_stats->used = jiffies;
  					new_stats->packet_count = 1;

  					new_stats->byte_count = len;

  					new_stats->tcp_flags = tcp_flags;
  					spin_lock_init(&new_stats->lock);

  					rcu_assign_pointer(flow->stats[cpu],

  							   new_stats);

  					cpumask_set_cpu(cpu, &flow->cpu_used_mask);

  					goto unlock;
  				}
  			}

  			flow->stats_last_writer = cpu;

  		}
  	}

  	stats->used = jiffies;
  	stats->packet_count++;

  	stats->byte_count += len;

  	stats->tcp_flags |= tcp_flags;

  unlock:

  	spin_unlock(&stats->lock);
  }

  /* Must be called with rcu_read_lock or ovs_mutex. */
  void ovs_flow_stats_get(const struct sw_flow *flow,
  			struct ovs_flow_stats *ovs_stats,

  			unsigned long *used, __be16 *tcp_flags)
  {

  	int cpu;

  
  	*used = 0;
  	*tcp_flags = 0;
  	memset(ovs_stats, 0, sizeof(*ovs_stats));

  	/* We open code this to make sure cpu 0 is always considered */

  	for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask)) {

  		struct sw_flow_stats *stats = rcu_dereference_ovsl(flow->stats[cpu]);

  
  		if (stats) {
  			/* Local CPU may write on non-local stats, so we must
  			 * block bottom-halves here.
  			 */
  			spin_lock_bh(&stats->lock);
  			if (!*used || time_after(stats->used, *used))
  				*used = stats->used;
  			*tcp_flags |= stats->tcp_flags;
  			ovs_stats->n_packets += stats->packet_count;
  			ovs_stats->n_bytes += stats->byte_count;
  			spin_unlock_bh(&stats->lock);
  		}

  	}

  }

  /* Called with ovs_mutex. */

  void ovs_flow_stats_clear(struct sw_flow *flow)
  {

  	int cpu;

  	/* We open code this to make sure cpu 0 is always considered */

  	for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask)) {

  		struct sw_flow_stats *stats = ovsl_dereference(flow->stats[cpu]);

  
  		if (stats) {
  			spin_lock_bh(&stats->lock);
  			stats->used = 0;
  			stats->packet_count = 0;
  			stats->byte_count = 0;
  			stats->tcp_flags = 0;
  			spin_unlock_bh(&stats->lock);
  		}
  	}

  }

  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));
  }

  static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)

  {

  	unsigned short frag_off;
  	unsigned int payload_ofs = 0;

  	unsigned int nh_ofs = skb_network_offset(skb);
  	unsigned int nh_len;

  	struct ipv6hdr *nh;

  	int err, nexthdr, flags = 0;

  	err = check_header(skb, nh_ofs + sizeof(*nh));
  	if (unlikely(err))
  		return err;
  
  	nh = ipv6_hdr(skb);

  
  	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;

  	nexthdr = ipv6_find_hdr(skb, &payload_ofs, -1, &frag_off, &flags);
  	if (flags & IP6_FH_F_FRAG) {

  		if (frag_off) {

  			key->ip.frag = OVS_FRAG_TYPE_LATER;

  			key->ip.proto = nexthdr;
  			return 0;
  		}
  		key->ip.frag = OVS_FRAG_TYPE_FIRST;

  	} else {
  		key->ip.frag = OVS_FRAG_TYPE_NONE;

  	}

  	/* Delayed handling of error in ipv6_find_hdr() as it
  	 * always sets flags and frag_off to a valid value which may be

  	 * used to set key->ip.frag above.
  	 */

  	if (unlikely(nexthdr < 0))

  		return -EPROTO;

  	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));
  }

  /**
   * Parse vlan tag from vlan header.
   * Returns ERROR on memory error.
   * Returns 0 if it encounters a non-vlan or incomplete packet.
   * Returns 1 after successfully parsing vlan tag.
   */

  static int parse_vlan_tag(struct sk_buff *skb, struct vlan_head *key_vh,
  			  bool untag_vlan)

  {

  	struct vlan_head *vh = (struct vlan_head *)skb->data;

  	if (likely(!eth_type_vlan(vh->tpid)))

  		return 0;

  	if (unlikely(skb->len < sizeof(struct vlan_head) + sizeof(__be16)))
  		return 0;
  
  	if (unlikely(!pskb_may_pull(skb, sizeof(struct vlan_head) +
  				 sizeof(__be16))))

  		return -ENOMEM;

  	vh = (struct vlan_head *)skb->data;

  	key_vh->tci = vh->tci | htons(VLAN_CFI_MASK);

  	key_vh->tpid = vh->tpid;

  	if (unlikely(untag_vlan)) {
  		int offset = skb->data - skb_mac_header(skb);
  		u16 tci;
  		int err;
  
  		__skb_push(skb, offset);
  		err = __skb_vlan_pop(skb, &tci);
  		__skb_pull(skb, offset);
  		if (err)
  			return err;
  		__vlan_hwaccel_put_tag(skb, key_vh->tpid, tci);
  	} else {
  		__skb_pull(skb, sizeof(struct vlan_head));
  	}

  	return 1;
  }

  static void clear_vlan(struct sw_flow_key *key)

  {

  	key->eth.vlan.tci = 0;
  	key->eth.vlan.tpid = 0;
  	key->eth.cvlan.tci = 0;
  	key->eth.cvlan.tpid = 0;

  }
  
  static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
  {
  	int res;

  	if (skb_vlan_tag_present(skb)) {

  		key->eth.vlan.tci = htons(skb->vlan_tci) | htons(VLAN_CFI_MASK);

  		key->eth.vlan.tpid = skb->vlan_proto;
  	} else {
  		/* Parse outer vlan tag in the non-accelerated case. */

  		res = parse_vlan_tag(skb, &key->eth.vlan, true);

  		if (res <= 0)
  			return res;
  	}
  
  	/* Parse inner vlan tag. */

  	res = parse_vlan_tag(skb, &key->eth.cvlan, false);

  	if (res <= 0)
  		return res;

  
  	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 (eth_proto_is_802_3(proto))

  		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 (eth_proto_is_802_3(llc->ethertype))

  		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->tp.src = htons(icmp->icmp6_type);
  	key->tp.dst = htons(icmp->icmp6_code);

  	memset(&key->ipv6.nd, 0, sizeof(key->ipv6.nd));

  
  	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;

  				ether_addr_copy(key->ipv6.nd.sll,
  						&nd->opt[offset+sizeof(*nd_opt)]);

  			} 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;

  				ether_addr_copy(key->ipv6.nd.tll,
  						&nd->opt[offset+sizeof(*nd_opt)]);

  			}
  
  			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;

  }

  static int parse_nsh(struct sk_buff *skb, struct sw_flow_key *key)
  {
  	struct nshhdr *nh;
  	unsigned int nh_ofs = skb_network_offset(skb);
  	u8 version, length;
  	int err;
  
  	err = check_header(skb, nh_ofs + NSH_BASE_HDR_LEN);
  	if (unlikely(err))
  		return err;
  
  	nh = nsh_hdr(skb);
  	version = nsh_get_ver(nh);
  	length = nsh_hdr_len(nh);
  
  	if (version != 0)
  		return -EINVAL;
  
  	err = check_header(skb, nh_ofs + length);
  	if (unlikely(err))
  		return err;
  
  	nh = nsh_hdr(skb);
  	key->nsh.base.flags = nsh_get_flags(nh);
  	key->nsh.base.ttl = nsh_get_ttl(nh);
  	key->nsh.base.mdtype = nh->mdtype;
  	key->nsh.base.np = nh->np;
  	key->nsh.base.path_hdr = nh->path_hdr;
  	switch (key->nsh.base.mdtype) {
  	case NSH_M_TYPE1:
  		if (length != NSH_M_TYPE1_LEN)
  			return -EINVAL;
  		memcpy(key->nsh.context, nh->md1.context,
  		       sizeof(nh->md1));
  		break;
  	case NSH_M_TYPE2:
  		memset(key->nsh.context, 0,
  		       sizeof(nh->md1));
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }

  /**

   * key_extract_l3l4 - extracts L3/L4 header information.

   * @skb: sk_buff that contains the frame, with skb->data pointing to the

   *       L3 header

   * @key: output flow key

   *

   */

  static int key_extract_l3l4(struct sk_buff *skb, struct sw_flow_key *key)

  {

  	int error;

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

  		error = check_iphdr(skb);
  		if (unlikely(error)) {

  			memset(&key->ip, 0, sizeof(key->ip));
  			memset(&key->ipv4, 0, sizeof(key->ipv4));

  			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;

  			memset(&key->tp, 0, sizeof(key->tp));

  			return 0;

  		}

  		if (nh->frag_off & htons(IP_MF) ||
  			skb_shinfo(skb)->gso_type & SKB_GSO_UDP)

  			key->ip.frag = OVS_FRAG_TYPE_FIRST;

  		else
  			key->ip.frag = OVS_FRAG_TYPE_NONE;

  
  		/* Transport layer. */
  		if (key->ip.proto == IPPROTO_TCP) {

  			if (tcphdr_ok(skb)) {
  				struct tcphdr *tcp = tcp_hdr(skb);

  				key->tp.src = tcp->source;
  				key->tp.dst = tcp->dest;
  				key->tp.flags = TCP_FLAGS_BE16(tcp);

  			} else {
  				memset(&key->tp, 0, sizeof(key->tp));

  			}

  		} else if (key->ip.proto == IPPROTO_UDP) {

  			if (udphdr_ok(skb)) {
  				struct udphdr *udp = udp_hdr(skb);

  				key->tp.src = udp->source;
  				key->tp.dst = udp->dest;

  			} else {
  				memset(&key->tp, 0, sizeof(key->tp));

  			}

  		} else if (key->ip.proto == IPPROTO_SCTP) {
  			if (sctphdr_ok(skb)) {
  				struct sctphdr *sctp = sctp_hdr(skb);

  				key->tp.src = sctp->source;
  				key->tp.dst = sctp->dest;

  			} else {
  				memset(&key->tp, 0, sizeof(key->tp));

  			}

  		} 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->tp.src = htons(icmp->type);
  				key->tp.dst = htons(icmp->code);

  			} else {
  				memset(&key->tp, 0, sizeof(key->tp));

  			}
  		}

  	} else if (key->eth.type == htons(ETH_P_ARP) ||
  		   key->eth.type == htons(ETH_P_RARP)) {

  		struct arp_eth_header *arp;

  		bool arp_available = arphdr_ok(skb);

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

  		if (arp_available &&

  		    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);

  			else
  				key->ip.proto = 0;

  			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));

  			ether_addr_copy(key->ipv4.arp.sha, arp->ar_sha);
  			ether_addr_copy(key->ipv4.arp.tha, arp->ar_tha);

  		} else {
  			memset(&key->ip, 0, sizeof(key->ip));
  			memset(&key->ipv4, 0, sizeof(key->ipv4));

  		}

  	} else if (eth_p_mpls(key->eth.type)) {

  		u8 label_count = 1;

  		memset(&key->mpls, 0, sizeof(key->mpls));

  		skb_set_inner_network_header(skb, skb->mac_len);

  		while (1) {
  			__be32 lse;

  			error = check_header(skb, skb->mac_len +
  					     label_count * MPLS_HLEN);

  			if (unlikely(error))
  				return 0;

  			memcpy(&lse, skb_inner_network_header(skb), MPLS_HLEN);

  			if (label_count <= MPLS_LABEL_DEPTH)
  				memcpy(&key->mpls.lse[label_count - 1], &lse,
  				       MPLS_HLEN);

  			skb_set_inner_network_header(skb, skb->mac_len +
  						     label_count * MPLS_HLEN);

  			if (lse & htonl(MPLS_LS_S_MASK))
  				break;

  			label_count++;

  		}

  		if (label_count > MPLS_LABEL_DEPTH)
  			label_count = MPLS_LABEL_DEPTH;
  
  		key->mpls.num_labels_mask = GENMASK(label_count - 1, 0);

  	} 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)) {

  			switch (nh_len) {
  			case -EINVAL:
  				memset(&key->ip, 0, sizeof(key->ip));
  				memset(&key->ipv6.addr, 0, sizeof(key->ipv6.addr));

  				fallthrough;

  			case -EPROTO:

  				skb->transport_header = skb->network_header;

  				error = 0;

  				break;
  			default:

  				error = nh_len;

  			}
  			return error;

  		}

  		if (key->ip.frag == OVS_FRAG_TYPE_LATER) {
  			memset(&key->tp, 0, sizeof(key->tp));

  			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->tp.src = tcp->source;
  				key->tp.dst = tcp->dest;
  				key->tp.flags = TCP_FLAGS_BE16(tcp);

  			} else {
  				memset(&key->tp, 0, sizeof(key->tp));

  			}
  		} else if (key->ip.proto == NEXTHDR_UDP) {

  			if (udphdr_ok(skb)) {
  				struct udphdr *udp = udp_hdr(skb);

  				key->tp.src = udp->source;
  				key->tp.dst = udp->dest;

  			} else {
  				memset(&key->tp, 0, sizeof(key->tp));

  			}

  		} else if (key->ip.proto == NEXTHDR_SCTP) {
  			if (sctphdr_ok(skb)) {
  				struct sctphdr *sctp = sctp_hdr(skb);

  				key->tp.src = sctp->source;
  				key->tp.dst = sctp->dest;

  			} else {
  				memset(&key->tp, 0, sizeof(key->tp));

  			}

  		} else if (key->ip.proto == NEXTHDR_ICMP) {

  			if (icmp6hdr_ok(skb)) {

  				error = parse_icmpv6(skb, key, nh_len);
  				if (error)
  					return error;

  			} else {
  				memset(&key->tp, 0, sizeof(key->tp));

  			}
  		}

  	} else if (key->eth.type == htons(ETH_P_NSH)) {
  		error = parse_nsh(skb, key);
  		if (error)
  			return error;

  	}

  	return 0;

  }

  /**
   * key_extract - extracts a flow key from an Ethernet frame.
   * @skb: sk_buff that contains the frame, with skb->data pointing to the
   * Ethernet header
   * @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 fields as follows:
   *
   *    - skb->mac_header: the L2 header.
   *
   *    - skb->network_header: just past the L2 header, or just past the
   *      VLAN header, to the first byte of the L2 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.
   *
   *    - skb->protocol: the type of the data starting at skb->network_header.
   *      Equals to key->eth.type.
   */
  static int key_extract(struct sk_buff *skb, struct sw_flow_key *key)
  {
  	struct ethhdr *eth;
  
  	/* Flags are always used as part of stats */
  	key->tp.flags = 0;
  
  	skb_reset_mac_header(skb);
  
  	/* Link layer. */
  	clear_vlan(key);
  	if (ovs_key_mac_proto(key) == MAC_PROTO_NONE) {
  		if (unlikely(eth_type_vlan(skb->protocol)))
  			return -EINVAL;
  
  		skb_reset_network_header(skb);
  		key->eth.type = skb->protocol;
  	} else {
  		eth = eth_hdr(skb);
  		ether_addr_copy(key->eth.src, eth->h_source);
  		ether_addr_copy(key->eth.dst, eth->h_dest);
  
  		__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 (unlikely(parse_vlan(skb, key)))
  			return -ENOMEM;
  
  		key->eth.type = parse_ethertype(skb);
  		if (unlikely(key->eth.type == htons(0)))
  			return -ENOMEM;
  
  		/* Multiple tagged packets need to retain TPID to satisfy
  		 * skb_vlan_pop(), which will later shift the ethertype into
  		 * skb->protocol.
  		 */
  		if (key->eth.cvlan.tci & htons(VLAN_CFI_MASK))
  			skb->protocol = key->eth.cvlan.tpid;
  		else
  			skb->protocol = key->eth.type;
  
  		skb_reset_network_header(skb);
  		__skb_push(skb, skb->data - skb_mac_header(skb));
  	}
  
  	skb_reset_mac_len(skb);
  
  	/* Fill out L3/L4 key info, if any */
  	return key_extract_l3l4(skb, key);
  }
  
  /* In the case of conntrack fragment handling it expects L3 headers,
   * add a helper.
   */
  int ovs_flow_key_update_l3l4(struct sk_buff *skb, struct sw_flow_key *key)
  {
  	return key_extract_l3l4(skb, key);
  }

  int ovs_flow_key_update(struct sk_buff *skb, struct sw_flow_key *key)
  {

  	int res;
  
  	res = key_extract(skb, key);
  	if (!res)
  		key->mac_proto &= ~SW_FLOW_KEY_INVALID;
  
  	return res;

  }

  static int key_extract_mac_proto(struct sk_buff *skb)
  {
  	switch (skb->dev->type) {
  	case ARPHRD_ETHER:
  		return MAC_PROTO_ETHERNET;
  	case ARPHRD_NONE:
  		if (skb->protocol == htons(ETH_P_TEB))
  			return MAC_PROTO_ETHERNET;
  		return MAC_PROTO_NONE;
  	}
  	WARN_ON_ONCE(1);
  	return -EINVAL;
  }

  int ovs_flow_key_extract(const struct ip_tunnel_info *tun_info,

  			 struct sk_buff *skb, struct sw_flow_key *key)

  {

  #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
  	struct tc_skb_ext *tc_ext;
  #endif

  	int res, err;

  	/* Extract metadata from packet. */

  	if (tun_info) {

  		key->tun_proto = ip_tunnel_info_af(tun_info);

  		memcpy(&key->tun_key, &tun_info->key, sizeof(key->tun_key));

  		if (tun_info->options_len) {

  			BUILD_BUG_ON((1 << (sizeof(tun_info->options_len) *
  						   8)) - 1
  					> sizeof(key->tun_opts));

  
  			ip_tunnel_info_opts_get(TUN_METADATA_OPTS(key, tun_info->options_len),
  						tun_info);

  			key->tun_opts_len = tun_info->options_len;
  		} else {
  			key->tun_opts_len = 0;
  		}
  	} else  {

  		key->tun_proto = 0;

  		key->tun_opts_len = 0;

  		memset(&key->tun_key, 0, sizeof(key->tun_key));

  	}

  
  	key->phy.priority = skb->priority;
  	key->phy.in_port = OVS_CB(skb)->input_vport->port_no;
  	key->phy.skb_mark = skb->mark;

  	key->ovs_flow_hash = 0;

  	res = key_extract_mac_proto(skb);
  	if (res < 0)
  		return res;
  	key->mac_proto = res;

  
  #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
  	if (static_branch_unlikely(&tc_recirc_sharing_support)) {
  		tc_ext = skb_ext_find(skb, TC_SKB_EXT);
  		key->recirc_id = tc_ext ? tc_ext->chain : 0;

  		OVS_CB(skb)->mru = tc_ext ? tc_ext->mru : 0;

  	} else {
  		key->recirc_id = 0;
  	}
  #else

  	key->recirc_id = 0;

  #endif

  	err = key_extract(skb, key);
  	if (!err)
  		ovs_ct_fill_key(skb, key);   /* Must be after key_extract(). */
  	return err;

  }

  int ovs_flow_key_extract_userspace(struct net *net, const struct nlattr *attr,

  				   struct sk_buff *skb,

  				   struct sw_flow_key *key, bool log)

  {

  	const struct nlattr *a[OVS_KEY_ATTR_MAX + 1];
  	u64 attrs = 0;

  	int err;

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

  	/* Extract metadata from netlink attributes. */

  	err = ovs_nla_get_flow_metadata(net, a, attrs, key, log);

  	if (err)
  		return err;

  	/* key_extract assumes that skb->protocol is set-up for
  	 * layer 3 packets which is the case for other callers,
  	 * in particular packets received from the network stack.
  	 * Here the correct value can be set from the metadata
  	 * extracted above.
  	 * For L2 packet key eth type would be zero. skb protocol
  	 * would be set to correct value later during key-extact.
  	 */

  	skb->protocol = key->eth.type;

  	err = key_extract(skb, key);
  	if (err)
  		return err;
  
  	/* Check that we have conntrack original direction tuple metadata only
  	 * for packets for which it makes sense.  Otherwise the key may be
  	 * corrupted due to overlapping key fields.
  	 */
  	if (attrs & (1 << OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV4) &&
  	    key->eth.type != htons(ETH_P_IP))
  		return -EINVAL;
  	if (attrs & (1 << OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV6) &&
  	    (key->eth.type != htons(ETH_P_IPV6) ||
  	     sw_flow_key_is_nd(key)))
  		return -EINVAL;
  
  	return 0;

  }