text: /*
   * Copyright (c) 2015 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.
   */
  
  #include <linux/module.h>
  #include <linux/openvswitch.h>
  #include <linux/tcp.h>
  #include <linux/udp.h>
  #include <linux/sctp.h>
  #include <linux/static_key.h>
  #include <net/ip.h>
  #include <net/genetlink.h>
  #include <net/netfilter/nf_conntrack_core.h>
  #include <net/netfilter/nf_conntrack_count.h>
  #include <net/netfilter/nf_conntrack_helper.h>
  #include <net/netfilter/nf_conntrack_labels.h>
  #include <net/netfilter/nf_conntrack_seqadj.h>
  #include <net/netfilter/nf_conntrack_zones.h>
  #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
  #include <net/ipv6_frag.h>
  
  #ifdef CONFIG_NF_NAT_NEEDED
  #include <linux/netfilter/nf_nat.h>
  #include <net/netfilter/nf_nat_core.h>
  #include <net/netfilter/nf_nat_l3proto.h>
  #endif
  
  #include "datapath.h"
  #include "conntrack.h"
  #include "flow.h"
  #include "flow_netlink.h"
  
  struct ovs_ct_len_tbl {
  	int maxlen;
  	int minlen;
  };
  
  /* Metadata mark for masked write to conntrack mark */
  struct md_mark {
  	u32 value;
  	u32 mask;
  };
  
  /* Metadata label for masked write to conntrack label. */
  struct md_labels {
  	struct ovs_key_ct_labels value;
  	struct ovs_key_ct_labels mask;
  };
  
  enum ovs_ct_nat {
  	OVS_CT_NAT = 1 << 0,     /* NAT for committed connections only. */
  	OVS_CT_SRC_NAT = 1 << 1, /* Source NAT for NEW connections. */
  	OVS_CT_DST_NAT = 1 << 2, /* Destination NAT for NEW connections. */
  };
  
  /* Conntrack action context for execution. */
  struct ovs_conntrack_info {
  	struct nf_conntrack_helper *helper;
  	struct nf_conntrack_zone zone;
  	struct nf_conn *ct;
  	u8 commit : 1;
  	u8 nat : 3;                 /* enum ovs_ct_nat */
  	u8 force : 1;
  	u8 have_eventmask : 1;
  	u16 family;
  	u32 eventmask;              /* Mask of 1 << IPCT_*. */
  	struct md_mark mark;
  	struct md_labels labels;
  #ifdef CONFIG_NF_NAT_NEEDED
  	struct nf_nat_range2 range;  /* Only present for SRC NAT and DST NAT. */
  #endif
  };
  
  #if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
  #define OVS_CT_LIMIT_UNLIMITED	0
  #define OVS_CT_LIMIT_DEFAULT OVS_CT_LIMIT_UNLIMITED
  #define CT_LIMIT_HASH_BUCKETS 512
  static DEFINE_STATIC_KEY_FALSE(ovs_ct_limit_enabled);
  
  struct ovs_ct_limit {
  	/* Elements in ovs_ct_limit_info->limits hash table */
  	struct hlist_node hlist_node;
  	struct rcu_head rcu;
  	u16 zone;
  	u32 limit;
  };
  
  struct ovs_ct_limit_info {
  	u32 default_limit;
  	struct hlist_head *limits;
  	struct nf_conncount_data *data;
  };
  
  static const struct nla_policy ct_limit_policy[OVS_CT_LIMIT_ATTR_MAX + 1] = {
  	[OVS_CT_LIMIT_ATTR_ZONE_LIMIT] = { .type = NLA_NESTED, },
  };
  #endif
  
  static bool labels_nonzero(const struct ovs_key_ct_labels *labels);
  
  static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info);
  
  static u16 key_to_nfproto(const struct sw_flow_key *key)
  {
  	switch (ntohs(key->eth.type)) {
  	case ETH_P_IP:
  		return NFPROTO_IPV4;
  	case ETH_P_IPV6:
  		return NFPROTO_IPV6;
  	default:
  		return NFPROTO_UNSPEC;
  	}
  }
  
  /* Map SKB connection state into the values used by flow definition. */
  static u8 ovs_ct_get_state(enum ip_conntrack_info ctinfo)
  {
  	u8 ct_state = OVS_CS_F_TRACKED;
  
  	switch (ctinfo) {
  	case IP_CT_ESTABLISHED_REPLY:
  	case IP_CT_RELATED_REPLY:
  		ct_state |= OVS_CS_F_REPLY_DIR;
  		break;
  	default:
  		break;
  	}
  
  	switch (ctinfo) {
  	case IP_CT_ESTABLISHED:
  	case IP_CT_ESTABLISHED_REPLY:
  		ct_state |= OVS_CS_F_ESTABLISHED;
  		break;
  	case IP_CT_RELATED:
  	case IP_CT_RELATED_REPLY:
  		ct_state |= OVS_CS_F_RELATED;
  		break;
  	case IP_CT_NEW:
  		ct_state |= OVS_CS_F_NEW;
  		break;
  	default:
  		break;
  	}
  
  	return ct_state;
  }
  
  static u32 ovs_ct_get_mark(const struct nf_conn *ct)
  {
  #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
  	return ct ? ct->mark : 0;
  #else
  	return 0;
  #endif
  }
  
  /* Guard against conntrack labels max size shrinking below 128 bits. */
  #if NF_CT_LABELS_MAX_SIZE < 16
  #error NF_CT_LABELS_MAX_SIZE must be at least 16 bytes
  #endif
  
  static void ovs_ct_get_labels(const struct nf_conn *ct,
  			      struct ovs_key_ct_labels *labels)
  {
  	struct nf_conn_labels *cl = ct ? nf_ct_labels_find(ct) : NULL;
  
  	if (cl)
  		memcpy(labels, cl->bits, OVS_CT_LABELS_LEN);
  	else
  		memset(labels, 0, OVS_CT_LABELS_LEN);
  }
  
  static void __ovs_ct_update_key_orig_tp(struct sw_flow_key *key,
  					const struct nf_conntrack_tuple *orig,
  					u8 icmp_proto)
  {
  	key->ct_orig_proto = orig->dst.protonum;
  	if (orig->dst.protonum == icmp_proto) {
  		key->ct.orig_tp.src = htons(orig->dst.u.icmp.type);
  		key->ct.orig_tp.dst = htons(orig->dst.u.icmp.code);
  	} else {
  		key->ct.orig_tp.src = orig->src.u.all;
  		key->ct.orig_tp.dst = orig->dst.u.all;
  	}
  }
  
  static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state,
  				const struct nf_conntrack_zone *zone,
  				const struct nf_conn *ct)
  {
  	key->ct_state = state;
  	key->ct_zone = zone->id;
  	key->ct.mark = ovs_ct_get_mark(ct);
  	ovs_ct_get_labels(ct, &key->ct.labels);
  
  	if (ct) {
  		const struct nf_conntrack_tuple *orig;
  
  		/* Use the master if we have one. */
  		if (ct->master)
  			ct = ct->master;
  		orig = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
  
  		/* IP version must match with the master connection. */
  		if (key->eth.type == htons(ETH_P_IP) &&
  		    nf_ct_l3num(ct) == NFPROTO_IPV4) {
  			key->ipv4.ct_orig.src = orig->src.u3.ip;
  			key->ipv4.ct_orig.dst = orig->dst.u3.ip;
  			__ovs_ct_update_key_orig_tp(key, orig, IPPROTO_ICMP);
  			return;
  		} else if (key->eth.type == htons(ETH_P_IPV6) &&
  			   !sw_flow_key_is_nd(key) &&
  			   nf_ct_l3num(ct) == NFPROTO_IPV6) {
  			key->ipv6.ct_orig.src = orig->src.u3.in6;
  			key->ipv6.ct_orig.dst = orig->dst.u3.in6;
  			__ovs_ct_update_key_orig_tp(key, orig, NEXTHDR_ICMP);
  			return;
  		}
  	}
  	/* Clear 'ct_orig_proto' to mark the non-existence of conntrack
  	 * original direction key fields.
  	 */
  	key->ct_orig_proto = 0;
  }
  
  /* Update 'key' based on skb->_nfct.  If 'post_ct' is true, then OVS has
   * previously sent the packet to conntrack via the ct action.  If
   * 'keep_nat_flags' is true, the existing NAT flags retained, else they are
   * initialized from the connection status.
   */
  static void ovs_ct_update_key(const struct sk_buff *skb,
  			      const struct ovs_conntrack_info *info,
  			      struct sw_flow_key *key, bool post_ct,
  			      bool keep_nat_flags)
  {
  	const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
  	enum ip_conntrack_info ctinfo;
  	struct nf_conn *ct;
  	u8 state = 0;
  
  	ct = nf_ct_get(skb, &ctinfo);
  	if (ct) {
  		state = ovs_ct_get_state(ctinfo);
  		/* All unconfirmed entries are NEW connections. */
  		if (!nf_ct_is_confirmed(ct))
  			state |= OVS_CS_F_NEW;
  		/* OVS persists the related flag for the duration of the
  		 * connection.
  		 */
  		if (ct->master)
  			state |= OVS_CS_F_RELATED;
  		if (keep_nat_flags) {
  			state |= key->ct_state & OVS_CS_F_NAT_MASK;
  		} else {
  			if (ct->status & IPS_SRC_NAT)
  				state |= OVS_CS_F_SRC_NAT;
  			if (ct->status & IPS_DST_NAT)
  				state |= OVS_CS_F_DST_NAT;
  		}
  		zone = nf_ct_zone(ct);
  	} else if (post_ct) {
  		state = OVS_CS_F_TRACKED | OVS_CS_F_INVALID;
  		if (info)
  			zone = &info->zone;
  	}
  	__ovs_ct_update_key(key, state, zone, ct);
  }
  
  /* This is called to initialize CT key fields possibly coming in from the local
   * stack.
   */
  void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key)
  {
  	ovs_ct_update_key(skb, NULL, key, false, false);
  }
  
  #define IN6_ADDR_INITIALIZER(ADDR) \
  	{ (ADDR).s6_addr32[0], (ADDR).s6_addr32[1], \
  	  (ADDR).s6_addr32[2], (ADDR).s6_addr32[3] }
  
  int ovs_ct_put_key(const struct sw_flow_key *swkey,
  		   const struct sw_flow_key *output, struct sk_buff *skb)
  {
  	if (nla_put_u32(skb, OVS_KEY_ATTR_CT_STATE, output->ct_state))
  		return -EMSGSIZE;
  
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
  	    nla_put_u16(skb, OVS_KEY_ATTR_CT_ZONE, output->ct_zone))
  		return -EMSGSIZE;
  
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
  	    nla_put_u32(skb, OVS_KEY_ATTR_CT_MARK, output->ct.mark))
  		return -EMSGSIZE;
  
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
  	    nla_put(skb, OVS_KEY_ATTR_CT_LABELS, sizeof(output->ct.labels),
  		    &output->ct.labels))
  		return -EMSGSIZE;
  
  	if (swkey->ct_orig_proto) {
  		if (swkey->eth.type == htons(ETH_P_IP)) {
  			struct ovs_key_ct_tuple_ipv4 orig = {
  				output->ipv4.ct_orig.src,
  				output->ipv4.ct_orig.dst,
  				output->ct.orig_tp.src,
  				output->ct.orig_tp.dst,
  				output->ct_orig_proto,
  			};
  			if (nla_put(skb, OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV4,
  				    sizeof(orig), &orig))
  				return -EMSGSIZE;
  		} else if (swkey->eth.type == htons(ETH_P_IPV6)) {
  			struct ovs_key_ct_tuple_ipv6 orig = {
  				IN6_ADDR_INITIALIZER(output->ipv6.ct_orig.src),
  				IN6_ADDR_INITIALIZER(output->ipv6.ct_orig.dst),
  				output->ct.orig_tp.src,
  				output->ct.orig_tp.dst,
  				output->ct_orig_proto,
  			};
  			if (nla_put(skb, OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV6,
  				    sizeof(orig), &orig))
  				return -EMSGSIZE;
  		}
  	}
  
  	return 0;
  }
  
  static int ovs_ct_set_mark(struct nf_conn *ct, struct sw_flow_key *key,
  			   u32 ct_mark, u32 mask)
  {
  #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
  	u32 new_mark;
  
  	new_mark = ct_mark | (ct->mark & ~(mask));
  	if (ct->mark != new_mark) {
  		ct->mark = new_mark;
  		if (nf_ct_is_confirmed(ct))
  			nf_conntrack_event_cache(IPCT_MARK, ct);
  		key->ct.mark = new_mark;
  	}
  
  	return 0;
  #else
  	return -ENOTSUPP;
  #endif
  }
  
  static struct nf_conn_labels *ovs_ct_get_conn_labels(struct nf_conn *ct)
  {
  	struct nf_conn_labels *cl;
  
  	cl = nf_ct_labels_find(ct);
  	if (!cl) {
  		nf_ct_labels_ext_add(ct);
  		cl = nf_ct_labels_find(ct);
  	}
  
  	return cl;
  }
  
  /* Initialize labels for a new, yet to be committed conntrack entry.  Note that
   * since the new connection is not yet confirmed, and thus no-one else has
   * access to it's labels, we simply write them over.
   */
  static int ovs_ct_init_labels(struct nf_conn *ct, struct sw_flow_key *key,
  			      const struct ovs_key_ct_labels *labels,
  			      const struct ovs_key_ct_labels *mask)
  {
  	struct nf_conn_labels *cl, *master_cl;
  	bool have_mask = labels_nonzero(mask);
  
  	/* Inherit master's labels to the related connection? */
  	master_cl = ct->master ? nf_ct_labels_find(ct->master) : NULL;
  
  	if (!master_cl && !have_mask)
  		return 0;   /* Nothing to do. */
  
  	cl = ovs_ct_get_conn_labels(ct);
  	if (!cl)
  		return -ENOSPC;
  
  	/* Inherit the master's labels, if any. */
  	if (master_cl)
  		*cl = *master_cl;
  
  	if (have_mask) {
  		u32 *dst = (u32 *)cl->bits;
  		int i;
  
  		for (i = 0; i < OVS_CT_LABELS_LEN_32; i++)
  			dst[i] = (dst[i] & ~mask->ct_labels_32[i]) |
  				(labels->ct_labels_32[i]
  				 & mask->ct_labels_32[i]);
  	}
  
  	/* Labels are included in the IPCTNL_MSG_CT_NEW event only if the
  	 * IPCT_LABEL bit is set in the event cache.
  	 */
  	nf_conntrack_event_cache(IPCT_LABEL, ct);
  
  	memcpy(&key->ct.labels, cl->bits, OVS_CT_LABELS_LEN);
  
  	return 0;
  }
  
  static int ovs_ct_set_labels(struct nf_conn *ct, struct sw_flow_key *key,
  			     const struct ovs_key_ct_labels *labels,
  			     const struct ovs_key_ct_labels *mask)
  {
  	struct nf_conn_labels *cl;
  	int err;
  
  	cl = ovs_ct_get_conn_labels(ct);
  	if (!cl)
  		return -ENOSPC;
  
  	err = nf_connlabels_replace(ct, labels->ct_labels_32,
  				    mask->ct_labels_32,
  				    OVS_CT_LABELS_LEN_32);
  	if (err)
  		return err;
  
  	memcpy(&key->ct.labels, cl->bits, OVS_CT_LABELS_LEN);
  
  	return 0;
  }
  
  /* 'skb' should already be pulled to nh_ofs. */
  static int ovs_ct_helper(struct sk_buff *skb, u16 proto)
  {
  	const struct nf_conntrack_helper *helper;
  	const struct nf_conn_help *help;
  	enum ip_conntrack_info ctinfo;
  	unsigned int protoff;
  	struct nf_conn *ct;
  	int err;
  
  	ct = nf_ct_get(skb, &ctinfo);
  	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
  		return NF_ACCEPT;
  
  	help = nfct_help(ct);
  	if (!help)
  		return NF_ACCEPT;
  
  	helper = rcu_dereference(help->helper);
  	if (!helper)
  		return NF_ACCEPT;
  
  	switch (proto) {
  	case NFPROTO_IPV4:
  		protoff = ip_hdrlen(skb);
  		break;
  	case NFPROTO_IPV6: {
  		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
  		__be16 frag_off;
  		int ofs;
  
  		ofs = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
  				       &frag_off);
  		if (ofs < 0 || (frag_off & htons(~0x7)) != 0) {
  			pr_debug("proto header not found\n");
  			return NF_ACCEPT;
  		}
  		protoff = ofs;
  		break;
  	}
  	default:
  		WARN_ONCE(1, "helper invoked on non-IP family!");
  		return NF_DROP;
  	}
  
  	err = helper->help(skb, protoff, ct, ctinfo);
  	if (err != NF_ACCEPT)
  		return err;
  
  	/* Adjust seqs after helper.  This is needed due to some helpers (e.g.,
  	 * FTP with NAT) adusting the TCP payload size when mangling IP
  	 * addresses and/or port numbers in the text-based control connection.
  	 */
  	if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
  	    !nf_ct_seq_adjust(skb, ct, ctinfo, protoff))
  		return NF_DROP;
  	return NF_ACCEPT;
  }
  
  /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
   * value if 'skb' is freed.
   */
  static int handle_fragments(struct net *net, struct sw_flow_key *key,
  			    u16 zone, struct sk_buff *skb)
  {
  	struct ovs_skb_cb ovs_cb = *OVS_CB(skb);
  	int err;
  
  	if (key->eth.type == htons(ETH_P_IP)) {
  		enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
  
  		memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
  		err = ip_defrag(net, skb, user);
  		if (err)
  			return err;
  
  		ovs_cb.mru = IPCB(skb)->frag_max_size;
  #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
  	} else if (key->eth.type == htons(ETH_P_IPV6)) {
  		enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
  
  		memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
  		err = nf_ct_frag6_gather(net, skb, user);
  		if (err) {
  			if (err != -EINPROGRESS)
  				kfree_skb(skb);
  			return err;
  		}
  
  		key->ip.proto = ipv6_hdr(skb)->nexthdr;
  		ovs_cb.mru = IP6CB(skb)->frag_max_size;
  #endif
  	} else {
  		kfree_skb(skb);
  		return -EPFNOSUPPORT;
  	}
  
  	key->ip.frag = OVS_FRAG_TYPE_NONE;
  	skb_clear_hash(skb);
  	skb->ignore_df = 1;
  	*OVS_CB(skb) = ovs_cb;
  
  	return 0;
  }
  
  static struct nf_conntrack_expect *
  ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone,
  		   u16 proto, const struct sk_buff *skb)
  {
  	struct nf_conntrack_tuple tuple;
  	struct nf_conntrack_expect *exp;
  
  	if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, net, &tuple))
  		return NULL;
  
  	exp = __nf_ct_expect_find(net, zone, &tuple);
  	if (exp) {
  		struct nf_conntrack_tuple_hash *h;
  
  		/* Delete existing conntrack entry, if it clashes with the
  		 * expectation.  This can happen since conntrack ALGs do not
  		 * check for clashes between (new) expectations and existing
  		 * conntrack entries.  nf_conntrack_in() will check the
  		 * expectations only if a conntrack entry can not be found,
  		 * which can lead to OVS finding the expectation (here) in the
  		 * init direction, but which will not be removed by the
  		 * nf_conntrack_in() call, if a matching conntrack entry is
  		 * found instead.  In this case all init direction packets
  		 * would be reported as new related packets, while reply
  		 * direction packets would be reported as un-related
  		 * established packets.
  		 */
  		h = nf_conntrack_find_get(net, zone, &tuple);
  		if (h) {
  			struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
  
  			nf_ct_delete(ct, 0, 0);
  			nf_conntrack_put(&ct->ct_general);
  		}
  	}
  
  	return exp;
  }
  
  /* This replicates logic from nf_conntrack_core.c that is not exported. */
  static enum ip_conntrack_info
  ovs_ct_get_info(const struct nf_conntrack_tuple_hash *h)
  {
  	const struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
  
  	if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
  		return IP_CT_ESTABLISHED_REPLY;
  	/* Once we've had two way comms, always ESTABLISHED. */
  	if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status))
  		return IP_CT_ESTABLISHED;
  	if (test_bit(IPS_EXPECTED_BIT, &ct->status))
  		return IP_CT_RELATED;
  	return IP_CT_NEW;
  }
  
  /* Find an existing connection which this packet belongs to without
   * re-attributing statistics or modifying the connection state.  This allows an
   * skb->_nfct lost due to an upcall to be recovered during actions execution.
   *
   * Must be called with rcu_read_lock.
   *
   * On success, populates skb->_nfct and returns the connection.  Returns NULL
   * if there is no existing entry.
   */
  static struct nf_conn *
  ovs_ct_find_existing(struct net *net, const struct nf_conntrack_zone *zone,
  		     u8 l3num, struct sk_buff *skb, bool natted)
  {
  	struct nf_conntrack_tuple tuple;
  	struct nf_conntrack_tuple_hash *h;
  	struct nf_conn *ct;
  
  	if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), l3num,
  			       net, &tuple)) {
  		pr_debug("ovs_ct_find_existing: Can't get tuple\n");
  		return NULL;
  	}
  
  	/* Must invert the tuple if skb has been transformed by NAT. */
  	if (natted) {
  		struct nf_conntrack_tuple inverse;
  
  		if (!nf_ct_invert_tuplepr(&inverse, &tuple)) {
  			pr_debug("ovs_ct_find_existing: Inversion failed!\n");
  			return NULL;
  		}
  		tuple = inverse;
  	}
  
  	/* look for tuple match */
  	h = nf_conntrack_find_get(net, zone, &tuple);
  	if (!h)
  		return NULL;   /* Not found. */
  
  	ct = nf_ct_tuplehash_to_ctrack(h);
  
  	/* Inverted packet tuple matches the reverse direction conntrack tuple,
  	 * select the other tuplehash to get the right 'ctinfo' bits for this
  	 * packet.
  	 */
  	if (natted)
  		h = &ct->tuplehash[!h->tuple.dst.dir];
  
  	nf_ct_set(skb, ct, ovs_ct_get_info(h));
  	return ct;
  }
  
  static
  struct nf_conn *ovs_ct_executed(struct net *net,
  				const struct sw_flow_key *key,
  				const struct ovs_conntrack_info *info,
  				struct sk_buff *skb,
  				bool *ct_executed)
  {
  	struct nf_conn *ct = NULL;
  
  	/* If no ct, check if we have evidence that an existing conntrack entry
  	 * might be found for this skb.  This happens when we lose a skb->_nfct
  	 * due to an upcall, or if the direction is being forced.  If the
  	 * connection was not confirmed, it is not cached and needs to be run
  	 * through conntrack again.
  	 */
  	*ct_executed = (key->ct_state & OVS_CS_F_TRACKED) &&
  		       !(key->ct_state & OVS_CS_F_INVALID) &&
  		       (key->ct_zone == info->zone.id);
  
  	if (*ct_executed || (!key->ct_state && info->force)) {
  		ct = ovs_ct_find_existing(net, &info->zone, info->family, skb,
  					  !!(key->ct_state &
  					  OVS_CS_F_NAT_MASK));
  	}
  
  	return ct;
  }
  
  /* Determine whether skb->_nfct is equal to the result of conntrack lookup. */
  static bool skb_nfct_cached(struct net *net,
  			    const struct sw_flow_key *key,
  			    const struct ovs_conntrack_info *info,
  			    struct sk_buff *skb)
  {
  	enum ip_conntrack_info ctinfo;
  	struct nf_conn *ct;
  	bool ct_executed = true;
  
  	ct = nf_ct_get(skb, &ctinfo);
  	if (!ct)
  		ct = ovs_ct_executed(net, key, info, skb, &ct_executed);
  
  	if (ct)
  		nf_ct_get(skb, &ctinfo);
  	else
  		return false;
  
  	if (!net_eq(net, read_pnet(&ct->ct_net)))
  		return false;
  	if (!nf_ct_zone_equal_any(info->ct, nf_ct_zone(ct)))
  		return false;
  	if (info->helper) {
  		struct nf_conn_help *help;
  
  		help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
  		if (help && rcu_access_pointer(help->helper) != info->helper)
  			return false;
  	}
  	/* Force conntrack entry direction to the current packet? */
  	if (info->force && CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) {
  		/* Delete the conntrack entry if confirmed, else just release
  		 * the reference.
  		 */
  		if (nf_ct_is_confirmed(ct))
  			nf_ct_delete(ct, 0, 0);
  
  		nf_conntrack_put(&ct->ct_general);
  		nf_ct_set(skb, NULL, 0);
  		return false;
  	}
  
  	return ct_executed;
  }
  
  #ifdef CONFIG_NF_NAT_NEEDED
  /* Modelled after nf_nat_ipv[46]_fn().
   * range is only used for new, uninitialized NAT state.
   * Returns either NF_ACCEPT or NF_DROP.
   */
  static int ovs_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
  			      enum ip_conntrack_info ctinfo,
  			      const struct nf_nat_range2 *range,
  			      enum nf_nat_manip_type maniptype)
  {
  	int hooknum, nh_off, err = NF_ACCEPT;
  
  	nh_off = skb_network_offset(skb);
  	skb_pull_rcsum(skb, nh_off);
  
  	/* See HOOK2MANIP(). */
  	if (maniptype == NF_NAT_MANIP_SRC)
  		hooknum = NF_INET_LOCAL_IN; /* Source NAT */
  	else
  		hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */
  
  	switch (ctinfo) {
  	case IP_CT_RELATED:
  	case IP_CT_RELATED_REPLY:
  		if (IS_ENABLED(CONFIG_NF_NAT_IPV4) &&
  		    skb->protocol == htons(ETH_P_IP) &&
  		    ip_hdr(skb)->protocol == IPPROTO_ICMP) {
  			if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
  							   hooknum))
  				err = NF_DROP;
  			goto push;
  		} else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) &&
  			   skb->protocol == htons(ETH_P_IPV6)) {
  			__be16 frag_off;
  			u8 nexthdr = ipv6_hdr(skb)->nexthdr;
  			int hdrlen = ipv6_skip_exthdr(skb,
  						      sizeof(struct ipv6hdr),
  						      &nexthdr, &frag_off);
  
  			if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
  				if (!nf_nat_icmpv6_reply_translation(skb, ct,
  								     ctinfo,
  								     hooknum,
  								     hdrlen))
  					err = NF_DROP;
  				goto push;
  			}
  		}
  		/* Non-ICMP, fall thru to initialize if needed. */
  		/* fall through */
  	case IP_CT_NEW:
  		/* Seen it before?  This can happen for loopback, retrans,
  		 * or local packets.
  		 */
  		if (!nf_nat_initialized(ct, maniptype)) {
  			/* Initialize according to the NAT action. */
  			err = (range && range->flags & NF_NAT_RANGE_MAP_IPS)
  				/* Action is set up to establish a new
  				 * mapping.
  				 */
  				? nf_nat_setup_info(ct, range, maniptype)
  				: nf_nat_alloc_null_binding(ct, hooknum);
  			if (err != NF_ACCEPT)
  				goto push;
  		}
  		break;
  
  	case IP_CT_ESTABLISHED:
  	case IP_CT_ESTABLISHED_REPLY:
  		break;
  
  	default:
  		err = NF_DROP;
  		goto push;
  	}
  
  	err = nf_nat_packet(ct, ctinfo, hooknum, skb);
  push:
  	skb_push(skb, nh_off);
  	skb_postpush_rcsum(skb, skb->data, nh_off);
  
  	return err;
  }
  
  static void ovs_nat_update_key(struct sw_flow_key *key,
  			       const struct sk_buff *skb,
  			       enum nf_nat_manip_type maniptype)
  {
  	if (maniptype == NF_NAT_MANIP_SRC) {
  		__be16 src;
  
  		key->ct_state |= OVS_CS_F_SRC_NAT;
  		if (key->eth.type == htons(ETH_P_IP))
  			key->ipv4.addr.src = ip_hdr(skb)->saddr;
  		else if (key->eth.type == htons(ETH_P_IPV6))
  			memcpy(&key->ipv6.addr.src, &ipv6_hdr(skb)->saddr,
  			       sizeof(key->ipv6.addr.src));
  		else
  			return;
  
  		if (key->ip.proto == IPPROTO_UDP)
  			src = udp_hdr(skb)->source;
  		else if (key->ip.proto == IPPROTO_TCP)
  			src = tcp_hdr(skb)->source;
  		else if (key->ip.proto == IPPROTO_SCTP)
  			src = sctp_hdr(skb)->source;
  		else
  			return;
  
  		key->tp.src = src;
  	} else {
  		__be16 dst;
  
  		key->ct_state |= OVS_CS_F_DST_NAT;
  		if (key->eth.type == htons(ETH_P_IP))
  			key->ipv4.addr.dst = ip_hdr(skb)->daddr;
  		else if (key->eth.type == htons(ETH_P_IPV6))
  			memcpy(&key->ipv6.addr.dst, &ipv6_hdr(skb)->daddr,
  			       sizeof(key->ipv6.addr.dst));
  		else
  			return;
  
  		if (key->ip.proto == IPPROTO_UDP)
  			dst = udp_hdr(skb)->dest;
  		else if (key->ip.proto == IPPROTO_TCP)
  			dst = tcp_hdr(skb)->dest;
  		else if (key->ip.proto == IPPROTO_SCTP)
  			dst = sctp_hdr(skb)->dest;
  		else
  			return;
  
  		key->tp.dst = dst;
  	}
  }
  
  /* Returns NF_DROP if the packet should be dropped, NF_ACCEPT otherwise. */
  static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
  		      const struct ovs_conntrack_info *info,
  		      struct sk_buff *skb, struct nf_conn *ct,
  		      enum ip_conntrack_info ctinfo)
  {
  	enum nf_nat_manip_type maniptype;
  	int err;
  
  	/* Add NAT extension if not confirmed yet. */
  	if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
  		return NF_ACCEPT;   /* Can't NAT. */
  
  	/* Determine NAT type.
  	 * Check if the NAT type can be deduced from the tracked connection.
  	 * Make sure new expected connections (IP_CT_RELATED) are NATted only
  	 * when committing.
  	 */
  	if (info->nat & OVS_CT_NAT && ctinfo != IP_CT_NEW &&
  	    ct->status & IPS_NAT_MASK &&
  	    (ctinfo != IP_CT_RELATED || info->commit)) {
  		/* NAT an established or related connection like before. */
  		if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)
  			/* This is the REPLY direction for a connection
  			 * for which NAT was applied in the forward
  			 * direction.  Do the reverse NAT.
  			 */
  			maniptype = ct->status & IPS_SRC_NAT
  				? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC;
  		else
  			maniptype = ct->status & IPS_SRC_NAT
  				? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST;
  	} else if (info->nat & OVS_CT_SRC_NAT) {
  		maniptype = NF_NAT_MANIP_SRC;
  	} else if (info->nat & OVS_CT_DST_NAT) {
  		maniptype = NF_NAT_MANIP_DST;
  	} else {
  		return NF_ACCEPT; /* Connection is not NATed. */
  	}
  	err = ovs_ct_nat_execute(skb, ct, ctinfo, &info->range, maniptype);
  
  	/* Mark NAT done if successful and update the flow key. */
  	if (err == NF_ACCEPT)
  		ovs_nat_update_key(key, skb, maniptype);
  
  	return err;
  }
  #else /* !CONFIG_NF_NAT_NEEDED */
  static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
  		      const struct ovs_conntrack_info *info,
  		      struct sk_buff *skb, struct nf_conn *ct,
  		      enum ip_conntrack_info ctinfo)
  {
  	return NF_ACCEPT;
  }
  #endif
  
  /* Pass 'skb' through conntrack in 'net', using zone configured in 'info', if
   * not done already.  Update key with new CT state after passing the packet
   * through conntrack.
   * Note that if the packet is deemed invalid by conntrack, skb->_nfct will be
   * set to NULL and 0 will be returned.
   */
  static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
  			   const struct ovs_conntrack_info *info,
  			   struct sk_buff *skb)
  {
  	/* If we are recirculating packets to match on conntrack fields and
  	 * committing with a separate conntrack action,  then we don't need to
  	 * actually run the packet through conntrack twice unless it's for a
  	 * different zone.
  	 */
  	bool cached = skb_nfct_cached(net, key, info, skb);
  	enum ip_conntrack_info ctinfo;
  	struct nf_conn *ct;
  
  	if (!cached) {
  		struct nf_conn *tmpl = info->ct;
  		int err;
  
  		/* Associate skb with specified zone. */
  		if (tmpl) {
  			if (skb_nfct(skb))
  				nf_conntrack_put(skb_nfct(skb));
  			nf_conntrack_get(&tmpl->ct_general);
  			nf_ct_set(skb, tmpl, IP_CT_NEW);
  		}
  
  		err = nf_conntrack_in(net, info->family,
  				      NF_INET_PRE_ROUTING, skb);
  		if (err != NF_ACCEPT)
  			return -ENOENT;
  
  		/* Clear CT state NAT flags to mark that we have not yet done
  		 * NAT after the nf_conntrack_in() call.  We can actually clear
  		 * the whole state, as it will be re-initialized below.
  		 */
  		key->ct_state = 0;
  
  		/* Update the key, but keep the NAT flags. */
  		ovs_ct_update_key(skb, info, key, true, true);
  	}
  
  	ct = nf_ct_get(skb, &ctinfo);
  	if (ct) {
  		/* Packets starting a new connection must be NATted before the
  		 * helper, so that the helper knows about the NAT.  We enforce
  		 * this by delaying both NAT and helper calls for unconfirmed
  		 * connections until the committing CT action.  For later
  		 * packets NAT and Helper may be called in either order.
  		 *
  		 * NAT will be done only if the CT action has NAT, and only
  		 * once per packet (per zone), as guarded by the NAT bits in
  		 * the key->ct_state.
  		 */
  		if (info->nat && !(key->ct_state & OVS_CS_F_NAT_MASK) &&
  		    (nf_ct_is_confirmed(ct) || info->commit) &&
  		    ovs_ct_nat(net, key, info, skb, ct, ctinfo) != NF_ACCEPT) {
  			return -EINVAL;
  		}
  
  		/* Userspace may decide to perform a ct lookup without a helper
  		 * specified followed by a (recirculate and) commit with one.
  		 * Therefore, for unconfirmed connections which we will commit,
  		 * we need to attach the helper here.
  		 */
  		if (!nf_ct_is_confirmed(ct) && info->commit &&
  		    info->helper && !nfct_help(ct)) {
  			int err = __nf_ct_try_assign_helper(ct, info->ct,
  							    GFP_ATOMIC);
  			if (err)
  				return err;
  		}
  
  		/* Call the helper only if:
  		 * - nf_conntrack_in() was executed above ("!cached") for a
  		 *   confirmed connection, or
  		 * - When committing an unconfirmed connection.
  		 */
  		if ((nf_ct_is_confirmed(ct) ? !cached : info->commit) &&
  		    ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
  			return -EINVAL;
  		}
  	}
  
  	return 0;
  }
  
  /* Lookup connection and read fields into key. */
  static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
  			 const struct ovs_conntrack_info *info,
  			 struct sk_buff *skb)
  {
  	struct nf_conntrack_expect *exp;
  
  	/* If we pass an expected packet through nf_conntrack_in() the
  	 * expectation is typically removed, but the packet could still be
  	 * lost in upcall processing.  To prevent this from happening we
  	 * perform an explicit expectation lookup.  Expected connections are
  	 * always new, and will be passed through conntrack only when they are
  	 * committed, as it is OK to remove the expectation at that time.
  	 */
  	exp = ovs_ct_expect_find(net, &info->zone, info->family, skb);
  	if (exp) {
  		u8 state;
  
  		/* NOTE: New connections are NATted and Helped only when
  		 * committed, so we are not calling into NAT here.
  		 */
  		state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED;
  		__ovs_ct_update_key(key, state, &info->zone, exp->master);
  	} else {
  		struct nf_conn *ct;
  		int err;
  
  		err = __ovs_ct_lookup(net, key, info, skb);
  		if (err)
  			return err;
  
  		ct = (struct nf_conn *)skb_nfct(skb);
  		if (ct)
  			nf_ct_deliver_cached_events(ct);
  	}
  
  	return 0;
  }
  
  static bool labels_nonzero(const struct ovs_key_ct_labels *labels)
  {
  	size_t i;
  
  	for (i = 0; i < OVS_CT_LABELS_LEN_32; i++)
  		if (labels->ct_labels_32[i])
  			return true;
  
  	return false;
  }
  
  #if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
  static struct hlist_head *ct_limit_hash_bucket(
  	const struct ovs_ct_limit_info *info, u16 zone)
  {
  	return &info->limits[zone & (CT_LIMIT_HASH_BUCKETS - 1)];
  }
  
  /* Call with ovs_mutex */
  static void ct_limit_set(const struct ovs_ct_limit_info *info,
  			 struct ovs_ct_limit *new_ct_limit)
  {
  	struct ovs_ct_limit *ct_limit;
  	struct hlist_head *head;
  
  	head = ct_limit_hash_bucket(info, new_ct_limit->zone);
  	hlist_for_each_entry_rcu(ct_limit, head, hlist_node) {
  		if (ct_limit->zone == new_ct_limit->zone) {
  			hlist_replace_rcu(&ct_limit->hlist_node,
  					  &new_ct_limit->hlist_node);
  			kfree_rcu(ct_limit, rcu);
  			return;
  		}
  	}
  
  	hlist_add_head_rcu(&new_ct_limit->hlist_node, head);
  }
  
  /* Call with ovs_mutex */
  static void ct_limit_del(const struct ovs_ct_limit_info *info, u16 zone)
  {
  	struct ovs_ct_limit *ct_limit;
  	struct hlist_head *head;
  	struct hlist_node *n;
  
  	head = ct_limit_hash_bucket(info, zone);
  	hlist_for_each_entry_safe(ct_limit, n, head, hlist_node) {
  		if (ct_limit->zone == zone) {
  			hlist_del_rcu(&ct_limit->hlist_node);
  			kfree_rcu(ct_limit, rcu);
  			return;
  		}
  	}
  }
  
  /* Call with RCU read lock */
  static u32 ct_limit_get(const struct ovs_ct_limit_info *info, u16 zone)
  {
  	struct ovs_ct_limit *ct_limit;
  	struct hlist_head *head;
  
  	head = ct_limit_hash_bucket(info, zone);
  	hlist_for_each_entry_rcu(ct_limit, head, hlist_node) {
  		if (ct_limit->zone == zone)
  			return ct_limit->limit;
  	}
  
  	return info->default_limit;
  }
  
  static int ovs_ct_check_limit(struct net *net,
  			      const struct ovs_conntrack_info *info,
  			      const struct nf_conntrack_tuple *tuple)
  {
  	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
  	const struct ovs_ct_limit_info *ct_limit_info = ovs_net->ct_limit_info;
  	u32 per_zone_limit, connections;
  	u32 conncount_key;
  
  	conncount_key = info->zone.id;
  
  	per_zone_limit = ct_limit_get(ct_limit_info, info->zone.id);
  	if (per_zone_limit == OVS_CT_LIMIT_UNLIMITED)
  		return 0;
  
  	connections = nf_conncount_count(net, ct_limit_info->data,
  					 &conncount_key, tuple, &info->zone);
  	if (connections > per_zone_limit)
  		return -ENOMEM;
  
  	return 0;
  }
  #endif
  
  /* Lookup connection and confirm if unconfirmed. */
  static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
  			 const struct ovs_conntrack_info *info,
  			 struct sk_buff *skb)
  {
  	enum ip_conntrack_info ctinfo;
  	struct nf_conn *ct;
  	int err;
  
  	err = __ovs_ct_lookup(net, key, info, skb);
  	if (err)
  		return err;
  
  	/* The connection could be invalid, in which case this is a no-op.*/
  	ct = nf_ct_get(skb, &ctinfo);
  	if (!ct)
  		return 0;
  
  #if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
  	if (static_branch_unlikely(&ovs_ct_limit_enabled)) {
  		if (!nf_ct_is_confirmed(ct)) {
  			err = ovs_ct_check_limit(net, info,
  				&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
  			if (err) {
  				net_warn_ratelimited("openvswitch: zone: %u "
  					"execeeds conntrack limit\n",
  					info->zone.id);
  				return err;
  			}
  		}
  	}
  #endif
  
  	/* Set the conntrack event mask if given.  NEW and DELETE events have
  	 * their own groups, but the NFNLGRP_CONNTRACK_UPDATE group listener
  	 * typically would receive many kinds of updates.  Setting the event
  	 * mask allows those events to be filtered.  The set event mask will
  	 * remain in effect for the lifetime of the connection unless changed
  	 * by a further CT action with both the commit flag and the eventmask
  	 * option. */
  	if (info->have_eventmask) {
  		struct nf_conntrack_ecache *cache = nf_ct_ecache_find(ct);
  
  		if (cache)
  			cache->ctmask = info->eventmask;
  	}
  
  	/* Apply changes before confirming the connection so that the initial
  	 * conntrack NEW netlink event carries the values given in the CT
  	 * action.
  	 */
  	if (info->mark.mask) {
  		err = ovs_ct_set_mark(ct, key, info->mark.value,
  				      info->mark.mask);
  		if (err)
  			return err;
  	}
  	if (!nf_ct_is_confirmed(ct)) {
  		err = ovs_ct_init_labels(ct, key, &info->labels.value,
  					 &info->labels.mask);
  		if (err)
  			return err;
  	} else if (labels_nonzero(&info->labels.mask)) {
  		err = ovs_ct_set_labels(ct, key, &info->labels.value,
  					&info->labels.mask);
  		if (err)
  			return err;
  	}
  	/* This will take care of sending queued events even if the connection
  	 * is already confirmed.
  	 */
  	if (nf_conntrack_confirm(skb) != NF_ACCEPT)
  		return -EINVAL;
  
  	return 0;
  }
  
  /* Trim the skb to the length specified by the IP/IPv6 header,
   * removing any trailing lower-layer padding. This prepares the skb
   * for higher-layer processing that assumes skb->len excludes padding
   * (such as nf_ip_checksum). The caller needs to pull the skb to the
   * network header, and ensure ip_hdr/ipv6_hdr points to valid data.
   */
  static int ovs_skb_network_trim(struct sk_buff *skb)
  {
  	unsigned int len;
  	int err;
  
  	switch (skb->protocol) {
  	case htons(ETH_P_IP):
  		len = ntohs(ip_hdr(skb)->tot_len);
  		break;
  	case htons(ETH_P_IPV6):
  		len = sizeof(struct ipv6hdr)
  			+ ntohs(ipv6_hdr(skb)->payload_len);
  		break;
  	default:
  		len = skb->len;
  	}
  
  	err = pskb_trim_rcsum(skb, len);
  	if (err)
  		kfree_skb(skb);
  
  	return err;
  }
  
  /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
   * value if 'skb' is freed.
   */
  int ovs_ct_execute(struct net *net, struct sk_buff *skb,
  		   struct sw_flow_key *key,
  		   const struct ovs_conntrack_info *info)
  {
  	int nh_ofs;
  	int err;
  
  	/* The conntrack module expects to be working at L3. */
  	nh_ofs = skb_network_offset(skb);
  	skb_pull_rcsum(skb, nh_ofs);
  
  	err = ovs_skb_network_trim(skb);
  	if (err)
  		return err;
  
  	if (key->ip.frag != OVS_FRAG_TYPE_NONE) {
  		err = handle_fragments(net, key, info->zone.id, skb);
  		if (err)
  			return err;
  	}
  
  	if (info->commit)
  		err = ovs_ct_commit(net, key, info, skb);
  	else
  		err = ovs_ct_lookup(net, key, info, skb);
  
  	skb_push(skb, nh_ofs);
  	skb_postpush_rcsum(skb, skb->data, nh_ofs);
  	if (err)
  		kfree_skb(skb);
  	return err;
  }
  
  int ovs_ct_clear(struct sk_buff *skb, struct sw_flow_key *key)
  {
  	if (skb_nfct(skb)) {
  		nf_conntrack_put(skb_nfct(skb));
  		nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
  		ovs_ct_fill_key(skb, key);
  	}
  
  	return 0;
  }
  
  static int ovs_ct_add_helper(struct ovs_conntrack_info *info, const char *name,
  			     const struct sw_flow_key *key, bool log)
  {
  	struct nf_conntrack_helper *helper;
  	struct nf_conn_help *help;
  
  	helper = nf_conntrack_helper_try_module_get(name, info->family,
  						    key->ip.proto);
  	if (!helper) {
  		OVS_NLERR(log, "Unknown helper \"%s\"", name);
  		return -EINVAL;
  	}
  
  	help = nf_ct_helper_ext_add(info->ct, GFP_KERNEL);
  	if (!help) {
  		nf_conntrack_helper_put(helper);
  		return -ENOMEM;
  	}
  
  	rcu_assign_pointer(help->helper, helper);
  	info->helper = helper;
  
  	if (info->nat)
  		request_module("ip_nat_%s", name);
  
  	return 0;
  }
  
  #ifdef CONFIG_NF_NAT_NEEDED
  static int parse_nat(const struct nlattr *attr,
  		     struct ovs_conntrack_info *info, bool log)
  {
  	struct nlattr *a;
  	int rem;
  	bool have_ip_max = false;
  	bool have_proto_max = false;
  	bool ip_vers = (info->family == NFPROTO_IPV6);
  
  	nla_for_each_nested(a, attr, rem) {
  		static const int ovs_nat_attr_lens[OVS_NAT_ATTR_MAX + 1][2] = {
  			[OVS_NAT_ATTR_SRC] = {0, 0},
  			[OVS_NAT_ATTR_DST] = {0, 0},
  			[OVS_NAT_ATTR_IP_MIN] = {sizeof(struct in_addr),
  						 sizeof(struct in6_addr)},
  			[OVS_NAT_ATTR_IP_MAX] = {sizeof(struct in_addr),
  						 sizeof(struct in6_addr)},
  			[OVS_NAT_ATTR_PROTO_MIN] = {sizeof(u16), sizeof(u16)},
  			[OVS_NAT_ATTR_PROTO_MAX] = {sizeof(u16), sizeof(u16)},
  			[OVS_NAT_ATTR_PERSISTENT] = {0, 0},
  			[OVS_NAT_ATTR_PROTO_HASH] = {0, 0},
  			[OVS_NAT_ATTR_PROTO_RANDOM] = {0, 0},
  		};
  		int type = nla_type(a);
  
  		if (type > OVS_NAT_ATTR_MAX) {
  			OVS_NLERR(log, "Unknown NAT attribute (type=%d, max=%d)",
  				  type, OVS_NAT_ATTR_MAX);
  			return -EINVAL;
  		}
  
  		if (nla_len(a) != ovs_nat_attr_lens[type][ip_vers]) {
  			OVS_NLERR(log, "NAT attribute type %d has unexpected length (%d != %d)",
  				  type, nla_len(a),
  				  ovs_nat_attr_lens[type][ip_vers]);
  			return -EINVAL;
  		}
  
  		switch (type) {
  		case OVS_NAT_ATTR_SRC:
  		case OVS_NAT_ATTR_DST:
  			if (info->nat) {
  				OVS_NLERR(log, "Only one type of NAT may be specified");
  				return -ERANGE;
  			}
  			info->nat |= OVS_CT_NAT;
  			info->nat |= ((type == OVS_NAT_ATTR_SRC)
  					? OVS_CT_SRC_NAT : OVS_CT_DST_NAT);
  			break;
  
  		case OVS_NAT_ATTR_IP_MIN:
  			nla_memcpy(&info->range.min_addr, a,
  				   sizeof(info->range.min_addr));
  			info->range.flags |= NF_NAT_RANGE_MAP_IPS;
  			break;
  
  		case OVS_NAT_ATTR_IP_MAX:
  			have_ip_max = true;
  			nla_memcpy(&info->range.max_addr, a,
  				   sizeof(info->range.max_addr));
  			info->range.flags |= NF_NAT_RANGE_MAP_IPS;
  			break;
  
  		case OVS_NAT_ATTR_PROTO_MIN:
  			info->range.min_proto.all = htons(nla_get_u16(a));
  			info->range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
  			break;
  
  		case OVS_NAT_ATTR_PROTO_MAX:
  			have_proto_max = true;
  			info->range.max_proto.all = htons(nla_get_u16(a));
  			info->range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
  			break;
  
  		case OVS_NAT_ATTR_PERSISTENT:
  			info->range.flags |= NF_NAT_RANGE_PERSISTENT;
  			break;
  
  		case OVS_NAT_ATTR_PROTO_HASH:
  			info->range.flags |= NF_NAT_RANGE_PROTO_RANDOM;
  			break;
  
  		case OVS_NAT_ATTR_PROTO_RANDOM:
  			info->range.flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY;
  			break;
  
  		default:
  			OVS_NLERR(log, "Unknown nat attribute (%d)", type);
  			return -EINVAL;
  		}
  	}
  
  	if (rem > 0) {
  		OVS_NLERR(log, "NAT attribute has %d unknown bytes", rem);
  		return -EINVAL;
  	}
  	if (!info->nat) {
  		/* Do not allow flags if no type is given. */
  		if (info->range.flags) {
  			OVS_NLERR(log,
  				  "NAT flags may be given only when NAT range (SRC or DST) is also specified."
  				  );
  			return -EINVAL;
  		}
  		info->nat = OVS_CT_NAT;   /* NAT existing connections. */
  	} else if (!info->commit) {
  		OVS_NLERR(log,
  			  "NAT attributes may be specified only when CT COMMIT flag is also specified."
  			  );
  		return -EINVAL;
  	}
  	/* Allow missing IP_MAX. */
  	if (info->range.flags & NF_NAT_RANGE_MAP_IPS && !have_ip_max) {
  		memcpy(&info->range.max_addr, &info->range.min_addr,
  		       sizeof(info->range.max_addr));
  	}
  	/* Allow missing PROTO_MAX. */
  	if (info->range.flags & NF_NAT_RANGE_PROTO_SPECIFIED &&
  	    !have_proto_max) {
  		info->range.max_proto.all = info->range.min_proto.all;
  	}
  	return 0;
  }
  #endif
  
  static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = {
  	[OVS_CT_ATTR_COMMIT]	= { .minlen = 0, .maxlen = 0 },
  	[OVS_CT_ATTR_FORCE_COMMIT]	= { .minlen = 0, .maxlen = 0 },
  	[OVS_CT_ATTR_ZONE]	= { .minlen = sizeof(u16),
  				    .maxlen = sizeof(u16) },
  	[OVS_CT_ATTR_MARK]	= { .minlen = sizeof(struct md_mark),
  				    .maxlen = sizeof(struct md_mark) },
  	[OVS_CT_ATTR_LABELS]	= { .minlen = sizeof(struct md_labels),
  				    .maxlen = sizeof(struct md_labels) },
  	[OVS_CT_ATTR_HELPER]	= { .minlen = 1,
  				    .maxlen = NF_CT_HELPER_NAME_LEN },
  #ifdef CONFIG_NF_NAT_NEEDED
  	/* NAT length is checked when parsing the nested attributes. */
  	[OVS_CT_ATTR_NAT]	= { .minlen = 0, .maxlen = INT_MAX },
  #endif
  	[OVS_CT_ATTR_EVENTMASK]	= { .minlen = sizeof(u32),
  				    .maxlen = sizeof(u32) },
  };
  
  static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
  		    const char **helper, bool log)
  {
  	struct nlattr *a;
  	int rem;
  
  	nla_for_each_nested(a, attr, rem) {
  		int type = nla_type(a);
  		int maxlen;
  		int minlen;
  
  		if (type > OVS_CT_ATTR_MAX) {
  			OVS_NLERR(log,
  				  "Unknown conntrack attr (type=%d, max=%d)",
  				  type, OVS_CT_ATTR_MAX);
  			return -EINVAL;
  		}
  
  		maxlen = ovs_ct_attr_lens[type].maxlen;
  		minlen = ovs_ct_attr_lens[type].minlen;
  		if (nla_len(a) < minlen || nla_len(a) > maxlen) {
  			OVS_NLERR(log,
  				  "Conntrack attr type has unexpected length (type=%d, length=%d, expected=%d)",
  				  type, nla_len(a), maxlen);
  			return -EINVAL;
  		}
  
  		switch (type) {
  		case OVS_CT_ATTR_FORCE_COMMIT:
  			info->force = true;
  			/* fall through. */
  		case OVS_CT_ATTR_COMMIT:
  			info->commit = true;
  			break;
  #ifdef CONFIG_NF_CONNTRACK_ZONES
  		case OVS_CT_ATTR_ZONE:
  			info->zone.id = nla_get_u16(a);
  			break;
  #endif
  #ifdef CONFIG_NF_CONNTRACK_MARK
  		case OVS_CT_ATTR_MARK: {
  			struct md_mark *mark = nla_data(a);
  
  			if (!mark->mask) {
  				OVS_NLERR(log, "ct_mark mask cannot be 0");
  				return -EINVAL;
  			}
  			info->mark = *mark;
  			break;
  		}
  #endif
  #ifdef CONFIG_NF_CONNTRACK_LABELS
  		case OVS_CT_ATTR_LABELS: {
  			struct md_labels *labels = nla_data(a);
  
  			if (!labels_nonzero(&labels->mask)) {
  				OVS_NLERR(log, "ct_labels mask cannot be 0");
  				return -EINVAL;
  			}
  			info->labels = *labels;
  			break;
  		}
  #endif
  		case OVS_CT_ATTR_HELPER:
  			*helper = nla_data(a);
  			if (!memchr(*helper, '\0', nla_len(a))) {
  				OVS_NLERR(log, "Invalid conntrack helper");
  				return -EINVAL;
  			}
  			break;
  #ifdef CONFIG_NF_NAT_NEEDED
  		case OVS_CT_ATTR_NAT: {
  			int err = parse_nat(a, info, log);
  
  			if (err)
  				return err;
  			break;
  		}
  #endif
  		case OVS_CT_ATTR_EVENTMASK:
  			info->have_eventmask = true;
  			info->eventmask = nla_get_u32(a);
  			break;
  
  		default:
  			OVS_NLERR(log, "Unknown conntrack attr (%d)",
  				  type);
  			return -EINVAL;
  		}
  	}
  
  #ifdef CONFIG_NF_CONNTRACK_MARK
  	if (!info->commit && info->mark.mask) {
  		OVS_NLERR(log,
  			  "Setting conntrack mark requires 'commit' flag.");
  		return -EINVAL;
  	}
  #endif
  #ifdef CONFIG_NF_CONNTRACK_LABELS
  	if (!info->commit && labels_nonzero(&info->labels.mask)) {
  		OVS_NLERR(log,
  			  "Setting conntrack labels requires 'commit' flag.");
  		return -EINVAL;
  	}
  #endif
  	if (rem > 0) {
  		OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem);
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr)
  {
  	if (attr == OVS_KEY_ATTR_CT_STATE)
  		return true;
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
  	    attr == OVS_KEY_ATTR_CT_ZONE)
  		return true;
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
  	    attr == OVS_KEY_ATTR_CT_MARK)
  		return true;
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
  	    attr == OVS_KEY_ATTR_CT_LABELS) {
  		struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
  
  		return ovs_net->xt_label;
  	}
  
  	return false;
  }
  
  int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
  		       const struct sw_flow_key *key,
  		       struct sw_flow_actions **sfa,  bool log)
  {
  	struct ovs_conntrack_info ct_info;
  	const char *helper = NULL;
  	u16 family;
  	int err;
  
  	family = key_to_nfproto(key);
  	if (family == NFPROTO_UNSPEC) {
  		OVS_NLERR(log, "ct family unspecified");
  		return -EINVAL;
  	}
  
  	memset(&ct_info, 0, sizeof(ct_info));
  	ct_info.family = family;
  
  	nf_ct_zone_init(&ct_info.zone, NF_CT_DEFAULT_ZONE_ID,
  			NF_CT_DEFAULT_ZONE_DIR, 0);
  
  	err = parse_ct(attr, &ct_info, &helper, log);
  	if (err)
  		return err;
  
  	/* Set up template for tracking connections in specific zones. */
  	ct_info.ct = nf_ct_tmpl_alloc(net, &ct_info.zone, GFP_KERNEL);
  	if (!ct_info.ct) {
  		OVS_NLERR(log, "Failed to allocate conntrack template");
  		return -ENOMEM;
  	}
  	if (helper) {
  		err = ovs_ct_add_helper(&ct_info, helper, key, log);
  		if (err)
  			goto err_free_ct;
  	}
  
  	err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info,
  				 sizeof(ct_info), log);
  	if (err)
  		goto err_free_ct;
  
  	__set_bit(IPS_CONFIRMED_BIT, &ct_info.ct->status);
  	nf_conntrack_get(&ct_info.ct->ct_general);
  	return 0;
  err_free_ct:
  	__ovs_ct_free_action(&ct_info);
  	return err;
  }
  
  #ifdef CONFIG_NF_NAT_NEEDED
  static bool ovs_ct_nat_to_attr(const struct ovs_conntrack_info *info,
  			       struct sk_buff *skb)
  {
  	struct nlattr *start;
  
  	start = nla_nest_start(skb, OVS_CT_ATTR_NAT);
  	if (!start)
  		return false;
  
  	if (info->nat & OVS_CT_SRC_NAT) {
  		if (nla_put_flag(skb, OVS_NAT_ATTR_SRC))
  			return false;
  	} else if (info->nat & OVS_CT_DST_NAT) {
  		if (nla_put_flag(skb, OVS_NAT_ATTR_DST))
  			return false;
  	} else {
  		goto out;
  	}
  
  	if (info->range.flags & NF_NAT_RANGE_MAP_IPS) {
  		if (IS_ENABLED(CONFIG_NF_NAT_IPV4) &&
  		    info->family == NFPROTO_IPV4) {
  			if (nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MIN,
  					    info->range.min_addr.ip) ||
  			    (info->range.max_addr.ip
  			     != info->range.min_addr.ip &&
  			     (nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MAX,
  					      info->range.max_addr.ip))))
  				return false;
  		} else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) &&
  			   info->family == NFPROTO_IPV6) {
  			if (nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MIN,
  					     &info->range.min_addr.in6) ||
  			    (memcmp(&info->range.max_addr.in6,
  				    &info->range.min_addr.in6,
  				    sizeof(info->range.max_addr.in6)) &&
  			     (nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MAX,
  					       &info->range.max_addr.in6))))
  				return false;
  		} else {
  			return false;
  		}
  	}
  	if (info->range.flags & NF_NAT_RANGE_PROTO_SPECIFIED &&
  	    (nla_put_u16(skb, OVS_NAT_ATTR_PROTO_MIN,
  			 ntohs(info->range.min_proto.all)) ||
  	     (info->range.max_proto.all != info->range.min_proto.all &&
  	      nla_put_u16(skb, OVS_NAT_ATTR_PROTO_MAX,
  			  ntohs(info->range.max_proto.all)))))
  		return false;
  
  	if (info->range.flags & NF_NAT_RANGE_PERSISTENT &&
  	    nla_put_flag(skb, OVS_NAT_ATTR_PERSISTENT))
  		return false;
  	if (info->range.flags & NF_NAT_RANGE_PROTO_RANDOM &&
  	    nla_put_flag(skb, OVS_NAT_ATTR_PROTO_HASH))
  		return false;
  	if (info->range.flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY &&
  	    nla_put_flag(skb, OVS_NAT_ATTR_PROTO_RANDOM))
  		return false;
  out:
  	nla_nest_end(skb, start);
  
  	return true;
  }
  #endif
  
  int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info,
  			  struct sk_buff *skb)
  {
  	struct nlattr *start;
  
  	start = nla_nest_start(skb, OVS_ACTION_ATTR_CT);
  	if (!start)
  		return -EMSGSIZE;
  
  	if (ct_info->commit && nla_put_flag(skb, ct_info->force
  					    ? OVS_CT_ATTR_FORCE_COMMIT
  					    : OVS_CT_ATTR_COMMIT))
  		return -EMSGSIZE;
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
  	    nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id))
  		return -EMSGSIZE;
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && ct_info->mark.mask &&
  	    nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark),
  		    &ct_info->mark))
  		return -EMSGSIZE;
  	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
  	    labels_nonzero(&ct_info->labels.mask) &&
  	    nla_put(skb, OVS_CT_ATTR_LABELS, sizeof(ct_info->labels),
  		    &ct_info->labels))
  		return -EMSGSIZE;
  	if (ct_info->helper) {
  		if (nla_put_string(skb, OVS_CT_ATTR_HELPER,
  				   ct_info->helper->name))
  			return -EMSGSIZE;
  	}
  	if (ct_info->have_eventmask &&
  	    nla_put_u32(skb, OVS_CT_ATTR_EVENTMASK, ct_info->eventmask))
  		return -EMSGSIZE;
  
  #ifdef CONFIG_NF_NAT_NEEDED
  	if (ct_info->nat && !ovs_ct_nat_to_attr(ct_info, skb))
  		return -EMSGSIZE;
  #endif
  	nla_nest_end(skb, start);
  
  	return 0;
  }
  
  void ovs_ct_free_action(const struct nlattr *a)
  {
  	struct ovs_conntrack_info *ct_info = nla_data(a);
  
  	__ovs_ct_free_action(ct_info);
  }
  
  static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info)
  {
  	if (ct_info->helper)
  		nf_conntrack_helper_put(ct_info->helper);
  	if (ct_info->ct)
  		nf_ct_tmpl_free(ct_info->ct);
  }
  
  #if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
  static int ovs_ct_limit_init(struct net *net, struct ovs_net *ovs_net)
  {
  	int i, err;
  
  	ovs_net->ct_limit_info = kmalloc(sizeof(*ovs_net->ct_limit_info),
  					 GFP_KERNEL);
  	if (!ovs_net->ct_limit_info)
  		return -ENOMEM;
  
  	ovs_net->ct_limit_info->default_limit = OVS_CT_LIMIT_DEFAULT;
  	ovs_net->ct_limit_info->limits =
  		kmalloc_array(CT_LIMIT_HASH_BUCKETS, sizeof(struct hlist_head),
  			      GFP_KERNEL);
  	if (!ovs_net->ct_limit_info->limits) {
  		kfree(ovs_net->ct_limit_info);
  		return -ENOMEM;
  	}
  
  	for (i = 0; i < CT_LIMIT_HASH_BUCKETS; i++)
  		INIT_HLIST_HEAD(&ovs_net->ct_limit_info->limits[i]);
  
  	ovs_net->ct_limit_info->data =
  		nf_conncount_init(net, NFPROTO_INET, sizeof(u32));
  
  	if (IS_ERR(ovs_net->ct_limit_info->data)) {
  		err = PTR_ERR(ovs_net->ct_limit_info->data);
  		kfree(ovs_net->ct_limit_info->limits);
  		kfree(ovs_net->ct_limit_info);
  		pr_err("openvswitch: failed to init nf_conncount %d\n", err);
  		return err;
  	}
  	return 0;
  }
  
  static void ovs_ct_limit_exit(struct net *net, struct ovs_net *ovs_net)
  {
  	const struct ovs_ct_limit_info *info = ovs_net->ct_limit_info;
  	int i;
  
  	nf_conncount_destroy(net, NFPROTO_INET, info->data);
  	for (i = 0; i < CT_LIMIT_HASH_BUCKETS; ++i) {
  		struct hlist_head *head = &info->limits[i];
  		struct ovs_ct_limit *ct_limit;
  
  		hlist_for_each_entry_rcu(ct_limit, head, hlist_node)
  			kfree_rcu(ct_limit, rcu);
  	}
  	kfree(ovs_net->ct_limit_info->limits);
  	kfree(ovs_net->ct_limit_info);
  }
  
  static struct sk_buff *
  ovs_ct_limit_cmd_reply_start(struct genl_info *info, u8 cmd,
  			     struct ovs_header **ovs_reply_header)
  {
  	struct ovs_header *ovs_header = info->userhdr;
  	struct sk_buff *skb;
  
  	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
  	if (!skb)
  		return ERR_PTR(-ENOMEM);
  
  	*ovs_reply_header = genlmsg_put(skb, info->snd_portid,
  					info->snd_seq,
  					&dp_ct_limit_genl_family, 0, cmd);
  
  	if (!*ovs_reply_header) {
  		nlmsg_free(skb);
  		return ERR_PTR(-EMSGSIZE);
  	}
  	(*ovs_reply_header)->dp_ifindex = ovs_header->dp_ifindex;
  
  	return skb;
  }
  
  static bool check_zone_id(int zone_id, u16 *pzone)
  {
  	if (zone_id >= 0 && zone_id <= 65535) {
  		*pzone = (u16)zone_id;
  		return true;
  	}
  	return false;
  }
  
  static int ovs_ct_limit_set_zone_limit(struct nlattr *nla_zone_limit,
  				       struct ovs_ct_limit_info *info)
  {
  	struct ovs_zone_limit *zone_limit;
  	int rem;
  	u16 zone;
  
  	rem = NLA_ALIGN(nla_len(nla_zone_limit));
  	zone_limit = (struct ovs_zone_limit *)nla_data(nla_zone_limit);
  
  	while (rem >= sizeof(*zone_limit)) {
  		if (unlikely(zone_limit->zone_id ==
  				OVS_ZONE_LIMIT_DEFAULT_ZONE)) {
  			ovs_lock();
  			info->default_limit = zone_limit->limit;
  			ovs_unlock();
  		} else if (unlikely(!check_zone_id(
  				zone_limit->zone_id, &zone))) {
  			OVS_NLERR(true, "zone id is out of range");
  		} else {
  			struct ovs_ct_limit *ct_limit;
  
  			ct_limit = kmalloc(sizeof(*ct_limit), GFP_KERNEL);
  			if (!ct_limit)
  				return -ENOMEM;
  
  			ct_limit->zone = zone;
  			ct_limit->limit = zone_limit->limit;
  
  			ovs_lock();
  			ct_limit_set(info, ct_limit);
  			ovs_unlock();
  		}
  		rem -= NLA_ALIGN(sizeof(*zone_limit));
  		zone_limit = (struct ovs_zone_limit *)((u8 *)zone_limit +
  				NLA_ALIGN(sizeof(*zone_limit)));
  	}
  
  	if (rem)
  		OVS_NLERR(true, "set zone limit has %d unknown bytes", rem);
  
  	return 0;
  }
  
  static int ovs_ct_limit_del_zone_limit(struct nlattr *nla_zone_limit,
  				       struct ovs_ct_limit_info *info)
  {
  	struct ovs_zone_limit *zone_limit;
  	int rem;
  	u16 zone;
  
  	rem = NLA_ALIGN(nla_len(nla_zone_limit));
  	zone_limit = (struct ovs_zone_limit *)nla_data(nla_zone_limit);
  
  	while (rem >= sizeof(*zone_limit)) {
  		if (unlikely(zone_limit->zone_id ==
  				OVS_ZONE_LIMIT_DEFAULT_ZONE)) {
  			ovs_lock();
  			info->default_limit = OVS_CT_LIMIT_DEFAULT;
  			ovs_unlock();
  		} else if (unlikely(!check_zone_id(
  				zone_limit->zone_id, &zone))) {
  			OVS_NLERR(true, "zone id is out of range");
  		} else {
  			ovs_lock();
  			ct_limit_del(info, zone);
  			ovs_unlock();
  		}
  		rem -= NLA_ALIGN(sizeof(*zone_limit));
  		zone_limit = (struct ovs_zone_limit *)((u8 *)zone_limit +
  				NLA_ALIGN(sizeof(*zone_limit)));
  	}
  
  	if (rem)
  		OVS_NLERR(true, "del zone limit has %d unknown bytes", rem);
  
  	return 0;
  }
  
  static int ovs_ct_limit_get_default_limit(struct ovs_ct_limit_info *info,
  					  struct sk_buff *reply)
  {
  	struct ovs_zone_limit zone_limit;
  	int err;
  
  	zone_limit.zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE;
  	zone_limit.limit = info->default_limit;
  	err = nla_put_nohdr(reply, sizeof(zone_limit), &zone_limit);
  	if (err)
  		return err;
  
  	return 0;
  }
  
  static int __ovs_ct_limit_get_zone_limit(struct net *net,
  					 struct nf_conncount_data *data,
  					 u16 zone_id, u32 limit,
  					 struct sk_buff *reply)
  {
  	struct nf_conntrack_zone ct_zone;
  	struct ovs_zone_limit zone_limit;
  	u32 conncount_key = zone_id;
  
  	zone_limit.zone_id = zone_id;
  	zone_limit.limit = limit;
  	nf_ct_zone_init(&ct_zone, zone_id, NF_CT_DEFAULT_ZONE_DIR, 0);
  
  	zone_limit.count = nf_conncount_count(net, data, &conncount_key, NULL,
  					      &ct_zone);
  	return nla_put_nohdr(reply, sizeof(zone_limit), &zone_limit);
  }
  
  static int ovs_ct_limit_get_zone_limit(struct net *net,
  				       struct nlattr *nla_zone_limit,
  				       struct ovs_ct_limit_info *info,
  				       struct sk_buff *reply)
  {
  	struct ovs_zone_limit *zone_limit;
  	int rem, err;
  	u32 limit;
  	u16 zone;
  
  	rem = NLA_ALIGN(nla_len(nla_zone_limit));
  	zone_limit = (struct ovs_zone_limit *)nla_data(nla_zone_limit);
  
  	while (rem >= sizeof(*zone_limit)) {
  		if (unlikely(zone_limit->zone_id ==
  				OVS_ZONE_LIMIT_DEFAULT_ZONE)) {
  			err = ovs_ct_limit_get_default_limit(info, reply);
  			if (err)
  				return err;
  		} else if (unlikely(!check_zone_id(zone_limit->zone_id,
  							&zone))) {
  			OVS_NLERR(true, "zone id is out of range");
  		} else {
  			rcu_read_lock();
  			limit = ct_limit_get(info, zone);
  			rcu_read_unlock();
  
  			err = __ovs_ct_limit_get_zone_limit(
  				net, info->data, zone, limit, reply);
  			if (err)
  				return err;
  		}
  		rem -= NLA_ALIGN(sizeof(*zone_limit));
  		zone_limit = (struct ovs_zone_limit *)((u8 *)zone_limit +
  				NLA_ALIGN(sizeof(*zone_limit)));
  	}
  
  	if (rem)
  		OVS_NLERR(true, "get zone limit has %d unknown bytes", rem);
  
  	return 0;
  }
  
  static int ovs_ct_limit_get_all_zone_limit(struct net *net,
  					   struct ovs_ct_limit_info *info,
  					   struct sk_buff *reply)
  {
  	struct ovs_ct_limit *ct_limit;
  	struct hlist_head *head;
  	int i, err = 0;
  
  	err = ovs_ct_limit_get_default_limit(info, reply);
  	if (err)
  		return err;
  
  	rcu_read_lock();
  	for (i = 0; i < CT_LIMIT_HASH_BUCKETS; ++i) {
  		head = &info->limits[i];
  		hlist_for_each_entry_rcu(ct_limit, head, hlist_node) {
  			err = __ovs_ct_limit_get_zone_limit(net, info->data,
  				ct_limit->zone, ct_limit->limit, reply);
  			if (err)
  				goto exit_err;
  		}
  	}
  
  exit_err:
  	rcu_read_unlock();
  	return err;
  }
  
  static int ovs_ct_limit_cmd_set(struct sk_buff *skb, struct genl_info *info)
  {
  	struct nlattr **a = info->attrs;
  	struct sk_buff *reply;
  	struct ovs_header *ovs_reply_header;
  	struct ovs_net *ovs_net = net_generic(sock_net(skb->sk), ovs_net_id);
  	struct ovs_ct_limit_info *ct_limit_info = ovs_net->ct_limit_info;
  	int err;
  
  	reply = ovs_ct_limit_cmd_reply_start(info, OVS_CT_LIMIT_CMD_SET,
  					     &ovs_reply_header);
  	if (IS_ERR(reply))
  		return PTR_ERR(reply);
  
  	if (!a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]) {
  		err = -EINVAL;
  		goto exit_err;
  	}
  
  	err = ovs_ct_limit_set_zone_limit(a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT],
  					  ct_limit_info);
  	if (err)
  		goto exit_err;
  
  	static_branch_enable(&ovs_ct_limit_enabled);
  
  	genlmsg_end(reply, ovs_reply_header);
  	return genlmsg_reply(reply, info);
  
  exit_err:
  	nlmsg_free(reply);
  	return err;
  }
  
  static int ovs_ct_limit_cmd_del(struct sk_buff *skb, struct genl_info *info)
  {
  	struct nlattr **a = info->attrs;
  	struct sk_buff *reply;
  	struct ovs_header *ovs_reply_header;
  	struct ovs_net *ovs_net = net_generic(sock_net(skb->sk), ovs_net_id);
  	struct ovs_ct_limit_info *ct_limit_info = ovs_net->ct_limit_info;
  	int err;
  
  	reply = ovs_ct_limit_cmd_reply_start(info, OVS_CT_LIMIT_CMD_DEL,
  					     &ovs_reply_header);
  	if (IS_ERR(reply))
  		return PTR_ERR(reply);
  
  	if (!a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]) {
  		err = -EINVAL;
  		goto exit_err;
  	}
  
  	err = ovs_ct_limit_del_zone_limit(a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT],
  					  ct_limit_info);
  	if (err)
  		goto exit_err;
  
  	genlmsg_end(reply, ovs_reply_header);
  	return genlmsg_reply(reply, info);
  
  exit_err:
  	nlmsg_free(reply);
  	return err;
  }
  
  static int ovs_ct_limit_cmd_get(struct sk_buff *skb, struct genl_info *info)
  {
  	struct nlattr **a = info->attrs;
  	struct nlattr *nla_reply;
  	struct sk_buff *reply;
  	struct ovs_header *ovs_reply_header;
  	struct net *net = sock_net(skb->sk);
  	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
  	struct ovs_ct_limit_info *ct_limit_info = ovs_net->ct_limit_info;
  	int err;
  
  	reply = ovs_ct_limit_cmd_reply_start(info, OVS_CT_LIMIT_CMD_GET,
  					     &ovs_reply_header);
  	if (IS_ERR(reply))
  		return PTR_ERR(reply);
  
  	nla_reply = nla_nest_start(reply, OVS_CT_LIMIT_ATTR_ZONE_LIMIT);
  
  	if (a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]) {
  		err = ovs_ct_limit_get_zone_limit(
  			net, a[OVS_CT_LIMIT_ATTR_ZONE_LIMIT], ct_limit_info,
  			reply);
  		if (err)
  			goto exit_err;
  	} else {
  		err = ovs_ct_limit_get_all_zone_limit(net, ct_limit_info,
  						      reply);
  		if (err)
  			goto exit_err;
  	}
  
  	nla_nest_end(reply, nla_reply);
  	genlmsg_end(reply, ovs_reply_header);
  	return genlmsg_reply(reply, info);
  
  exit_err:
  	nlmsg_free(reply);
  	return err;
  }
  
  static struct genl_ops ct_limit_genl_ops[] = {
  	{ .cmd = OVS_CT_LIMIT_CMD_SET,
  		.flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
  					   * privilege. */
  		.policy = ct_limit_policy,
  		.doit = ovs_ct_limit_cmd_set,
  	},
  	{ .cmd = OVS_CT_LIMIT_CMD_DEL,
  		.flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
  					   * privilege. */
  		.policy = ct_limit_policy,
  		.doit = ovs_ct_limit_cmd_del,
  	},
  	{ .cmd = OVS_CT_LIMIT_CMD_GET,
  		.flags = 0,		  /* OK for unprivileged users. */
  		.policy = ct_limit_policy,
  		.doit = ovs_ct_limit_cmd_get,
  	},
  };
  
  static const struct genl_multicast_group ovs_ct_limit_multicast_group = {
  	.name = OVS_CT_LIMIT_MCGROUP,
  };
  
  struct genl_family dp_ct_limit_genl_family __ro_after_init = {
  	.hdrsize = sizeof(struct ovs_header),
  	.name = OVS_CT_LIMIT_FAMILY,
  	.version = OVS_CT_LIMIT_VERSION,
  	.maxattr = OVS_CT_LIMIT_ATTR_MAX,
  	.netnsok = true,
  	.parallel_ops = true,
  	.ops = ct_limit_genl_ops,
  	.n_ops = ARRAY_SIZE(ct_limit_genl_ops),
  	.mcgrps = &ovs_ct_limit_multicast_group,
  	.n_mcgrps = 1,
  	.module = THIS_MODULE,
  };
  #endif
  
  int ovs_ct_init(struct net *net)
  {
  	unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
  	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
  
  	if (nf_connlabels_get(net, n_bits - 1)) {
  		ovs_net->xt_label = false;
  		OVS_NLERR(true, "Failed to set connlabel length");
  	} else {
  		ovs_net->xt_label = true;
  	}
  
  #if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
  	return ovs_ct_limit_init(net, ovs_net);
  #else
  	return 0;
  #endif
  }
  
  void ovs_ct_exit(struct net *net)
  {
  	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
  
  #if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
  	ovs_ct_limit_exit(net, ovs_net);
  #endif
  
  	if (ovs_net->xt_label)
  		nf_connlabels_put(net);
  }
  