net/openvswitch/flow.c - kernel/msm-4.19 - Gitiles

 /*
  * 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/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/ndisc.h>

 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;
 }

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

 void ovs_flow_stats_update(struct sw_flow *flow, struct sk_buff *skb)
 {
 	struct flow_stats *stats;
 	__be16 tcp_flags = 0;

 	if (!flow->stats.is_percpu)
 		stats = flow->stats.stat;
 	else
 		stats = this_cpu_ptr(flow->stats.cpu_stats);

 	if ((flow->key.eth.type == htons(ETH_P_IP) ||
 	     flow->key.eth.type == htons(ETH_P_IPV6)) &&
 	    flow->key.ip.frag != OVS_FRAG_TYPE_LATER &&
 	    flow->key.ip.proto == IPPROTO_TCP &&
 	    likely(skb->len >= skb_transport_offset(skb) + sizeof(struct tcphdr))) {
 		tcp_flags = TCP_FLAGS_BE16(tcp_hdr(skb));
 	}

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

 static void stats_read(struct flow_stats *stats,
 		       struct ovs_flow_stats *ovs_stats,
 		       unsigned long *used, __be16 *tcp_flags)
 {
 	spin_lock(&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(&stats->lock);
 }

 void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
 			unsigned long *used, __be16 *tcp_flags)
 {
 	int cpu, cur_cpu;

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

 	if (!flow->stats.is_percpu) {
 		stats_read(flow->stats.stat, ovs_stats, used, tcp_flags);
 	} else {
 		cur_cpu = get_cpu();
 		for_each_possible_cpu(cpu) {
 			struct flow_stats *stats;

 			if (cpu == cur_cpu)
 				local_bh_disable();

 			stats = per_cpu_ptr(flow->stats.cpu_stats, cpu);
 			stats_read(stats, ovs_stats, used, tcp_flags);

 			if (cpu == cur_cpu)
 				local_bh_enable();
 		}
 		put_cpu();
 	}
 }

 static void stats_reset(struct flow_stats *stats)
 {
 	spin_lock(&stats->lock);
 	stats->used = 0;
 	stats->packet_count = 0;
 	stats->byte_count = 0;
 	stats->tcp_flags = 0;
 	spin_unlock(&stats->lock);
 }

 void ovs_flow_stats_clear(struct sw_flow *flow)
 {
 	int cpu, cur_cpu;

 	if (!flow->stats.is_percpu) {
 		stats_reset(flow->stats.stat);
 	} else {
 		cur_cpu = get_cpu();

 		for_each_possible_cpu(cpu) {

 			if (cpu == cur_cpu)
 				local_bh_disable();

 			stats_reset(per_cpu_ptr(flow->stats.cpu_stats, cpu));

 			if (cpu == cur_cpu)
 				local_bh_enable();
 		}
 		put_cpu();
 	}
 }

 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 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));
 }

 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;
 				key->ipv4.tp.flags = TCP_FLAGS_BE16(tcp);
 			}
 		} 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;
 				key->ipv6.tp.flags = TCP_FLAGS_BE16(tcp);
 			}
 		} 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;
 }
	/*
	* 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/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/ndisc.h>

	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;
	}

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

	void ovs_flow_stats_update(struct sw_flow flow, struct sk_buff skb)
	{
	struct flow_stats *stats;
	__be16 tcp_flags = 0;

	if (!flow->stats.is_percpu)
	stats = flow->stats.stat;
	else
	stats = this_cpu_ptr(flow->stats.cpu_stats);

	if ((flow->key.eth.type == htons(ETH_P_IP) \|\|
	flow->key.eth.type == htons(ETH_P_IPV6)) &&
	flow->key.ip.frag != OVS_FRAG_TYPE_LATER &&
	flow->key.ip.proto == IPPROTO_TCP &&
	likely(skb->len >= skb_transport_offset(skb) + sizeof(struct tcphdr))) {
	tcp_flags = TCP_FLAGS_BE16(tcp_hdr(skb));
	}

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

	static void stats_read(struct flow_stats *stats,
	struct ovs_flow_stats *ovs_stats,
	unsigned long used, __be16 tcp_flags)
	{
	spin_lock(&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(&stats->lock);
	}

	void ovs_flow_stats_get(struct sw_flow flow, struct ovs_flow_stats ovs_stats,
	unsigned long used, __be16 tcp_flags)
	{
	int cpu, cur_cpu;

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

	if (!flow->stats.is_percpu) {
	stats_read(flow->stats.stat, ovs_stats, used, tcp_flags);
	} else {
	cur_cpu = get_cpu();
	for_each_possible_cpu(cpu) {
	struct flow_stats *stats;

	if (cpu == cur_cpu)
	local_bh_disable();

	stats = per_cpu_ptr(flow->stats.cpu_stats, cpu);
	stats_read(stats, ovs_stats, used, tcp_flags);

	if (cpu == cur_cpu)
	local_bh_enable();
	}
	put_cpu();
	}
	}

	static void stats_reset(struct flow_stats *stats)
	{
	spin_lock(&stats->lock);
	stats->used = 0;
	stats->packet_count = 0;
	stats->byte_count = 0;
	stats->tcp_flags = 0;
	spin_unlock(&stats->lock);
	}

	void ovs_flow_stats_clear(struct sw_flow *flow)
	{
	int cpu, cur_cpu;

	if (!flow->stats.is_percpu) {
	stats_reset(flow->stats.stat);
	} else {
	cur_cpu = get_cpu();

	for_each_possible_cpu(cpu) {

	if (cpu == cur_cpu)
	local_bh_disable();

	stats_reset(per_cpu_ptr(flow->stats.cpu_stats, cpu));

	if (cpu == cur_cpu)
	local_bh_enable();
	}
	put_cpu();
	}
	}

	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 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));
	}

	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;
	key->ipv4.tp.flags = TCP_FLAGS_BE16(tcp);
	}
	} 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;
	key->ipv6.tp.flags = TCP_FLAGS_BE16(tcp);
	}
	} 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;
	}