text: /*
   * Copyright (c) 2008-2018 Nicira, Inc.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <config.h>
  
  #include "dpif-netlink.h"
  
  #include <ctype.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <inttypes.h>
  #include <net/if.h>
  #include <linux/types.h>
  #include <linux/pkt_sched.h>
  #include <poll.h>
  #include <stdlib.h>
  #include <strings.h>
  #include <sys/epoll.h>
  #include <sys/stat.h>
  #include <unistd.h>
  
  #include "bitmap.h"
  #include "dpif-netlink-rtnl.h"
  #include "dpif-provider.h"
  #include "fat-rwlock.h"
  #include "flow.h"
  #include "netdev-linux.h"
  #include "netdev-offload.h"
  #include "netdev-provider.h"
  #include "netdev-vport.h"
  #include "netdev.h"
  #include "netlink-conntrack.h"
  #include "netlink-notifier.h"
  #include "netlink-socket.h"
  #include "netlink.h"
  #include "netnsid.h"
  #include "odp-util.h"
  #include "openvswitch/dynamic-string.h"
  #include "openvswitch/flow.h"
  #include "openvswitch/hmap.h"
  #include "openvswitch/match.h"
  #include "openvswitch/ofpbuf.h"
  #include "openvswitch/poll-loop.h"
  #include "openvswitch/shash.h"
  #include "openvswitch/thread.h"
  #include "openvswitch/vlog.h"
  #include "packets.h"
  #include "random.h"
  #include "sset.h"
  #include "timeval.h"
  #include "unaligned.h"
  #include "util.h"
  
  VLOG_DEFINE_THIS_MODULE(dpif_netlink);
  #ifdef _WIN32
  #include "wmi.h"
  enum { WINDOWS = 1 };
  #else
  enum { WINDOWS = 0 };
  #endif
  enum { MAX_PORTS = USHRT_MAX };
  
  /* This ethtool flag was introduced in Linux 2.6.24, so it might be
   * missing if we have old headers. */
  #define ETH_FLAG_LRO      (1 << 15)    /* LRO is enabled */
  
  #define FLOW_DUMP_MAX_BATCH 50
  #define OPERATE_MAX_OPS 50
  
  #ifndef EPOLLEXCLUSIVE
  #define EPOLLEXCLUSIVE (1u << 28)
  #endif
  
  struct dpif_netlink_dp {
      /* Generic Netlink header. */
      uint8_t cmd;
  
      /* struct ovs_header. */
      int dp_ifindex;
  
      /* Attributes. */
      const char *name;                  /* OVS_DP_ATTR_NAME. */
      const uint32_t *upcall_pid;        /* OVS_DP_ATTR_UPCALL_PID. */
      uint32_t user_features;            /* OVS_DP_ATTR_USER_FEATURES */
      const struct ovs_dp_stats *stats;  /* OVS_DP_ATTR_STATS. */
      const struct ovs_dp_megaflow_stats *megaflow_stats;
                                         /* OVS_DP_ATTR_MEGAFLOW_STATS.*/
  };
  
  static void dpif_netlink_dp_init(struct dpif_netlink_dp *);
  static int dpif_netlink_dp_from_ofpbuf(struct dpif_netlink_dp *,
                                         const struct ofpbuf *);
  static void dpif_netlink_dp_dump_start(struct nl_dump *);
  static int dpif_netlink_dp_transact(const struct dpif_netlink_dp *request,
                                      struct dpif_netlink_dp *reply,
                                      struct ofpbuf **bufp);
  static int dpif_netlink_dp_get(const struct dpif *,
                                 struct dpif_netlink_dp *reply,
                                 struct ofpbuf **bufp);
  
  struct dpif_netlink_flow {
      /* Generic Netlink header. */
      uint8_t cmd;
  
      /* struct ovs_header. */
      unsigned int nlmsg_flags;
      int dp_ifindex;
  
      /* Attributes.
       *
       * The 'stats' member points to 64-bit data that might only be aligned on
       * 32-bit boundaries, so get_unaligned_u64() should be used to access its
       * values.
       *
       * If 'actions' is nonnull then OVS_FLOW_ATTR_ACTIONS will be included in
       * the Netlink version of the command, even if actions_len is zero. */
      const struct nlattr *key;           /* OVS_FLOW_ATTR_KEY. */
      size_t key_len;
      const struct nlattr *mask;          /* OVS_FLOW_ATTR_MASK. */
      size_t mask_len;
      const struct nlattr *actions;       /* OVS_FLOW_ATTR_ACTIONS. */
      size_t actions_len;
      ovs_u128 ufid;                      /* OVS_FLOW_ATTR_FLOW_ID. */
      bool ufid_present;                  /* Is there a UFID? */
      bool ufid_terse;                    /* Skip serializing key/mask/acts? */
      const struct ovs_flow_stats *stats; /* OVS_FLOW_ATTR_STATS. */
      const uint8_t *tcp_flags;           /* OVS_FLOW_ATTR_TCP_FLAGS. */
      const ovs_32aligned_u64 *used;      /* OVS_FLOW_ATTR_USED. */
      bool clear;                         /* OVS_FLOW_ATTR_CLEAR. */
      bool probe;                         /* OVS_FLOW_ATTR_PROBE. */
  };
  
  static void dpif_netlink_flow_init(struct dpif_netlink_flow *);
  static int dpif_netlink_flow_from_ofpbuf(struct dpif_netlink_flow *,
                                           const struct ofpbuf *);
  static void dpif_netlink_flow_to_ofpbuf(const struct dpif_netlink_flow *,
                                          struct ofpbuf *);
  static int dpif_netlink_flow_transact(struct dpif_netlink_flow *request,
                                        struct dpif_netlink_flow *reply,
                                        struct ofpbuf **bufp);
  static void dpif_netlink_flow_get_stats(const struct dpif_netlink_flow *,
                                          struct dpif_flow_stats *);
  static void dpif_netlink_flow_to_dpif_flow(struct dpif *, struct dpif_flow *,
                                             const struct dpif_netlink_flow *);
  
  /* One of the dpif channels between the kernel and userspace. */
  struct dpif_channel {
      struct nl_sock *sock;       /* Netlink socket. */
      long long int last_poll;    /* Last time this channel was polled. */
  };
  
  #ifdef _WIN32
  #define VPORT_SOCK_POOL_SIZE 1
  /* On Windows, there is no native support for epoll.  There are equivalent
   * interfaces though, that are not used currently.  For simpicity, a pool of
   * netlink sockets is used.  Each socket is represented by 'struct
   * dpif_windows_vport_sock'.  Since it is a pool, multiple OVS ports may be
   * sharing the same socket.  In the future, we can add a reference count and
   * such fields. */
  struct dpif_windows_vport_sock {
      struct nl_sock *nl_sock;    /* netlink socket. */
  };
  #endif
  
  struct dpif_handler {
      struct epoll_event *epoll_events;
      int epoll_fd;                 /* epoll fd that includes channel socks. */
      int n_events;                 /* Num events returned by epoll_wait(). */
      int event_offset;             /* Offset into 'epoll_events'. */
  
  #ifdef _WIN32
      /* Pool of sockets. */
      struct dpif_windows_vport_sock *vport_sock_pool;
      size_t last_used_pool_idx; /* Index to aid in allocating a
                                    socket in the pool to a port. */
  #endif
  };
  
  /* Datapath interface for the openvswitch Linux kernel module. */
  struct dpif_netlink {
      struct dpif dpif;
      int dp_ifindex;
  
      /* Upcall messages. */
      struct fat_rwlock upcall_lock;
      struct dpif_handler *handlers;
      uint32_t n_handlers;           /* Num of upcall handlers. */
      struct dpif_channel *channels; /* Array of channels for each port. */
      int uc_array_size;             /* Size of 'handler->channels' and */
                                     /* 'handler->epoll_events'. */
  
      /* Change notification. */
      struct nl_sock *port_notifier; /* vport multicast group subscriber. */
      bool refresh_channels;
  };
  
  static void report_loss(struct dpif_netlink *, struct dpif_channel *,
                          uint32_t ch_idx, uint32_t handler_id);
  
  static struct vlog_rate_limit error_rl = VLOG_RATE_LIMIT_INIT(9999, 5);
  
  /* Generic Netlink family numbers for OVS.
   *
   * Initialized by dpif_netlink_init(). */
  static int ovs_datapath_family;
  static int ovs_vport_family;
  static int ovs_flow_family;
  static int ovs_packet_family;
  static int ovs_meter_family;
  static int ovs_ct_limit_family;
  
  /* Generic Netlink multicast groups for OVS.
   *
   * Initialized by dpif_netlink_init(). */
  static unsigned int ovs_vport_mcgroup;
  
  /* If true, tunnel devices are created using OVS compat/genetlink.
   * If false, tunnel devices are created with rtnetlink and using light weight
   * tunnels. If we fail to create the tunnel the rtnetlink+LWT, then we fallback
   * to using the compat interface. */
  static bool ovs_tunnels_out_of_tree = true;
  
  static int dpif_netlink_init(void);
  static int open_dpif(const struct dpif_netlink_dp *, struct dpif **);
  static uint32_t dpif_netlink_port_get_pid(const struct dpif *,
                                            odp_port_t port_no);
  static void dpif_netlink_handler_uninit(struct dpif_handler *handler);
  static int dpif_netlink_refresh_channels(struct dpif_netlink *,
                                           uint32_t n_handlers);
  static void dpif_netlink_vport_to_ofpbuf(const struct dpif_netlink_vport *,
                                           struct ofpbuf *);
  static int dpif_netlink_vport_from_ofpbuf(struct dpif_netlink_vport *,
                                            const struct ofpbuf *);
  static int dpif_netlink_port_query__(const struct dpif_netlink *dpif,
                                       odp_port_t port_no, const char *port_name,
                                       struct dpif_port *dpif_port);
  
  static int
  create_nl_sock(struct dpif_netlink *dpif OVS_UNUSED, struct nl_sock **sockp)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
  #ifndef _WIN32
      return nl_sock_create(NETLINK_GENERIC, sockp);
  #else
      /* Pick netlink sockets to use in a round-robin fashion from each
       * handler's pool of sockets. */
      struct dpif_handler *handler = &dpif->handlers[0];
      struct dpif_windows_vport_sock *sock_pool = handler->vport_sock_pool;
      size_t index = handler->last_used_pool_idx;
  
      /* A pool of sockets is allocated when the handler is initialized. */
      if (sock_pool == NULL) {
          *sockp = NULL;
          return EINVAL;
      }
  
      ovs_assert(index < VPORT_SOCK_POOL_SIZE);
      *sockp = sock_pool[index].nl_sock;
      ovs_assert(*sockp);
      index = (index == VPORT_SOCK_POOL_SIZE - 1) ? 0 : index + 1;
      handler->last_used_pool_idx = index;
      return 0;
  #endif
  }
  
  static void
  close_nl_sock(struct nl_sock *sock)
  {
  #ifndef _WIN32
      nl_sock_destroy(sock);
  #endif
  }
  
  static struct dpif_netlink *
  dpif_netlink_cast(const struct dpif *dpif)
  {
      dpif_assert_class(dpif, &dpif_netlink_class);
      return CONTAINER_OF(dpif, struct dpif_netlink, dpif);
  }
  
  static int
  dpif_netlink_enumerate(struct sset *all_dps,
                         const struct dpif_class *dpif_class OVS_UNUSED)
  {
      struct nl_dump dump;
      uint64_t reply_stub[NL_DUMP_BUFSIZE / 8];
      struct ofpbuf msg, buf;
      int error;
  
      error = dpif_netlink_init();
      if (error) {
          return error;
      }
  
      ofpbuf_use_stub(&buf, reply_stub, sizeof reply_stub);
      dpif_netlink_dp_dump_start(&dump);
      while (nl_dump_next(&dump, &msg, &buf)) {
          struct dpif_netlink_dp dp;
  
          if (!dpif_netlink_dp_from_ofpbuf(&dp, &msg)) {
              sset_add(all_dps, dp.name);
          }
      }
      ofpbuf_uninit(&buf);
      return nl_dump_done(&dump);
  }
  
  static int
  dpif_netlink_open(const struct dpif_class *class OVS_UNUSED, const char *name,
                    bool create, struct dpif **dpifp)
  {
      struct dpif_netlink_dp dp_request, dp;
      struct ofpbuf *buf;
      uint32_t upcall_pid;
      int error;
  
      error = dpif_netlink_init();
      if (error) {
          return error;
      }
  
      /* Create or look up datapath. */
      dpif_netlink_dp_init(&dp_request);
      if (create) {
          dp_request.cmd = OVS_DP_CMD_NEW;
          upcall_pid = 0;
          dp_request.upcall_pid = &upcall_pid;
      } else {
          /* Use OVS_DP_CMD_SET to report user features */
          dp_request.cmd = OVS_DP_CMD_SET;
      }
      dp_request.name = name;
      dp_request.user_features |= OVS_DP_F_UNALIGNED;
      dp_request.user_features |= OVS_DP_F_VPORT_PIDS;
      error = dpif_netlink_dp_transact(&dp_request, &dp, &buf);
      if (error) {
          return error;
      }
  
      error = open_dpif(&dp, dpifp);
      ofpbuf_delete(buf);
      return error;
  }
  
  static int
  open_dpif(const struct dpif_netlink_dp *dp, struct dpif **dpifp)
  {
      struct dpif_netlink *dpif;
  
      dpif = xzalloc(sizeof *dpif);
      dpif->port_notifier = NULL;
      fat_rwlock_init(&dpif->upcall_lock);
  
      dpif_init(&dpif->dpif, &dpif_netlink_class, dp->name,
                dp->dp_ifindex, dp->dp_ifindex);
  
      dpif->dp_ifindex = dp->dp_ifindex;
      *dpifp = &dpif->dpif;
  
      return 0;
  }
  
  #ifdef _WIN32
  static void
  vport_delete_sock_pool(struct dpif_handler *handler)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      if (handler->vport_sock_pool) {
          uint32_t i;
          struct dpif_windows_vport_sock *sock_pool =
              handler->vport_sock_pool;
  
          for (i = 0; i < VPORT_SOCK_POOL_SIZE; i++) {
              if (sock_pool[i].nl_sock) {
                  nl_sock_unsubscribe_packets(sock_pool[i].nl_sock);
                  nl_sock_destroy(sock_pool[i].nl_sock);
                  sock_pool[i].nl_sock = NULL;
              }
          }
  
          free(handler->vport_sock_pool);
          handler->vport_sock_pool = NULL;
      }
  }
  
  static int
  vport_create_sock_pool(struct dpif_handler *handler)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      struct dpif_windows_vport_sock *sock_pool;
      size_t i;
      int error = 0;
  
      sock_pool = xzalloc(VPORT_SOCK_POOL_SIZE * sizeof *sock_pool);
      for (i = 0; i < VPORT_SOCK_POOL_SIZE; i++) {
          error = nl_sock_create(NETLINK_GENERIC, &sock_pool[i].nl_sock);
          if (error) {
              goto error;
          }
  
          /* Enable the netlink socket to receive packets.  This is equivalent to
           * calling nl_sock_join_mcgroup() to receive events. */
          error = nl_sock_subscribe_packets(sock_pool[i].nl_sock);
          if (error) {
             goto error;
          }
      }
  
      handler->vport_sock_pool = sock_pool;
      handler->last_used_pool_idx = 0;
      return 0;
  
  error:
      vport_delete_sock_pool(handler);
      return error;
  }
  #endif /* _WIN32 */
  
  /* Given the port number 'port_idx', extracts the pid of netlink socket
   * associated to the port and assigns it to 'upcall_pid'. */
  static bool
  vport_get_pid(struct dpif_netlink *dpif, uint32_t port_idx,
                uint32_t *upcall_pid)
  {
      /* Since the nl_sock can only be assigned in either all
       * or none "dpif" channels, the following check
       * would suffice. */
      if (!dpif->channels[port_idx].sock) {
          return false;
      }
      ovs_assert(!WINDOWS || dpif->n_handlers <= 1);
  
      *upcall_pid = nl_sock_pid(dpif->channels[port_idx].sock);
  
      return true;
  }
  
  static int
  vport_add_channel(struct dpif_netlink *dpif, odp_port_t port_no,
                    struct nl_sock *sock)
  {
      struct epoll_event event;
      uint32_t port_idx = odp_to_u32(port_no);
      size_t i;
      int error;
  
      if (dpif->handlers == NULL) {
          close_nl_sock(sock);
          return 0;
      }
  
      /* We assume that the datapath densely chooses port numbers, which can
       * therefore be used as an index into 'channels' and 'epoll_events' of
       * 'dpif'. */
      if (port_idx >= dpif->uc_array_size) {
          uint32_t new_size = port_idx + 1;
  
          if (new_size > MAX_PORTS) {
              VLOG_WARN_RL(&error_rl, "%s: datapath port %"PRIu32" too big",
                           dpif_name(&dpif->dpif), port_no);
              return EFBIG;
          }
  
          dpif->channels = xrealloc(dpif->channels,
                                    new_size * sizeof *dpif->channels);
  
          for (i = dpif->uc_array_size; i < new_size; i++) {
              dpif->channels[i].sock = NULL;
          }
  
          for (i = 0; i < dpif->n_handlers; i++) {
              struct dpif_handler *handler = &dpif->handlers[i];
  
              handler->epoll_events = xrealloc(handler->epoll_events,
                  new_size * sizeof *handler->epoll_events);
  
          }
          dpif->uc_array_size = new_size;
      }
  
      memset(&event, 0, sizeof event);
      event.events = EPOLLIN | EPOLLEXCLUSIVE;
      event.data.u32 = port_idx;
  
      for (i = 0; i < dpif->n_handlers; i++) {
          struct dpif_handler *handler = &dpif->handlers[i];
  
  #ifndef _WIN32
          if (epoll_ctl(handler->epoll_fd, EPOLL_CTL_ADD, nl_sock_fd(sock),
                        &event) < 0) {
              error = errno;
              goto error;
          }
  #endif
      }
      dpif->channels[port_idx].sock = sock;
      dpif->channels[port_idx].last_poll = LLONG_MIN;
  
      return 0;
  
  error:
  #ifndef _WIN32
      while (i--) {
          epoll_ctl(dpif->handlers[i].epoll_fd, EPOLL_CTL_DEL,
                    nl_sock_fd(sock), NULL);
      }
  #endif
      dpif->channels[port_idx].sock = NULL;
  
      return error;
  }
  
  static void
  vport_del_channels(struct dpif_netlink *dpif, odp_port_t port_no)
  {
      uint32_t port_idx = odp_to_u32(port_no);
      size_t i;
  
      if (!dpif->handlers || port_idx >= dpif->uc_array_size
          || !dpif->channels[port_idx].sock) {
          return;
      }
  
      for (i = 0; i < dpif->n_handlers; i++) {
          struct dpif_handler *handler = &dpif->handlers[i];
  #ifndef _WIN32
          epoll_ctl(handler->epoll_fd, EPOLL_CTL_DEL,
                    nl_sock_fd(dpif->channels[port_idx].sock), NULL);
  #endif
          handler->event_offset = handler->n_events = 0;
      }
  #ifndef _WIN32
      nl_sock_destroy(dpif->channels[port_idx].sock);
  #endif
      dpif->channels[port_idx].sock = NULL;
  }
  
  static void
  destroy_all_channels(struct dpif_netlink *dpif)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      unsigned int i;
  
      if (!dpif->handlers) {
          return;
      }
  
      for (i = 0; i < dpif->uc_array_size; i++ ) {
          struct dpif_netlink_vport vport_request;
          uint32_t upcall_pids = 0;
  
          if (!dpif->channels[i].sock) {
              continue;
          }
  
          /* Turn off upcalls. */
          dpif_netlink_vport_init(&vport_request);
          vport_request.cmd = OVS_VPORT_CMD_SET;
          vport_request.dp_ifindex = dpif->dp_ifindex;
          vport_request.port_no = u32_to_odp(i);
          vport_request.n_upcall_pids = 1;
          vport_request.upcall_pids = &upcall_pids;
          dpif_netlink_vport_transact(&vport_request, NULL, NULL);
  
          vport_del_channels(dpif, u32_to_odp(i));
      }
  
      for (i = 0; i < dpif->n_handlers; i++) {
          struct dpif_handler *handler = &dpif->handlers[i];
  
          dpif_netlink_handler_uninit(handler);
          free(handler->epoll_events);
      }
      free(dpif->channels);
      free(dpif->handlers);
      dpif->handlers = NULL;
      dpif->channels = NULL;
      dpif->n_handlers = 0;
      dpif->uc_array_size = 0;
  }
  
  static void
  dpif_netlink_close(struct dpif *dpif_)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
  
      nl_sock_destroy(dpif->port_notifier);
  
      fat_rwlock_wrlock(&dpif->upcall_lock);
      destroy_all_channels(dpif);
      fat_rwlock_unlock(&dpif->upcall_lock);
  
      fat_rwlock_destroy(&dpif->upcall_lock);
      free(dpif);
  }
  
  static int
  dpif_netlink_destroy(struct dpif *dpif_)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct dpif_netlink_dp dp;
  
      dpif_netlink_dp_init(&dp);
      dp.cmd = OVS_DP_CMD_DEL;
      dp.dp_ifindex = dpif->dp_ifindex;
      return dpif_netlink_dp_transact(&dp, NULL, NULL);
  }
  
  static bool
  dpif_netlink_run(struct dpif *dpif_)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
  
      if (dpif->refresh_channels) {
          dpif->refresh_channels = false;
          fat_rwlock_wrlock(&dpif->upcall_lock);
          dpif_netlink_refresh_channels(dpif, dpif->n_handlers);
          fat_rwlock_unlock(&dpif->upcall_lock);
      }
      return false;
  }
  
  static int
  dpif_netlink_get_stats(const struct dpif *dpif_, struct dpif_dp_stats *stats)
  {
      struct dpif_netlink_dp dp;
      struct ofpbuf *buf;
      int error;
  
      error = dpif_netlink_dp_get(dpif_, &dp, &buf);
      if (!error) {
          memset(stats, 0, sizeof *stats);
  
          if (dp.stats) {
              stats->n_hit    = get_32aligned_u64(&dp.stats->n_hit);
              stats->n_missed = get_32aligned_u64(&dp.stats->n_missed);
              stats->n_lost   = get_32aligned_u64(&dp.stats->n_lost);
              stats->n_flows  = get_32aligned_u64(&dp.stats->n_flows);
          }
  
          if (dp.megaflow_stats) {
              stats->n_masks = dp.megaflow_stats->n_masks;
              stats->n_mask_hit = get_32aligned_u64(
                  &dp.megaflow_stats->n_mask_hit);
          } else {
              stats->n_masks = UINT32_MAX;
              stats->n_mask_hit = UINT64_MAX;
          }
          ofpbuf_delete(buf);
      }
      return error;
  }
  
  static const char *
  get_vport_type(const struct dpif_netlink_vport *vport)
  {
      static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
  
      switch (vport->type) {
      case OVS_VPORT_TYPE_NETDEV: {
          const char *type = netdev_get_type_from_name(vport->name);
  
          return type ? type : "system";
      }
  
      case OVS_VPORT_TYPE_INTERNAL:
          return "internal";
  
      case OVS_VPORT_TYPE_GENEVE:
          return "geneve";
  
      case OVS_VPORT_TYPE_GRE:
          return "gre";
  
      case OVS_VPORT_TYPE_VXLAN:
          return "vxlan";
  
      case OVS_VPORT_TYPE_LISP:
          return "lisp";
  
      case OVS_VPORT_TYPE_STT:
          return "stt";
  
      case OVS_VPORT_TYPE_ERSPAN:
          return "erspan";
  
      case OVS_VPORT_TYPE_IP6ERSPAN:
          return "ip6erspan"; 
  
      case OVS_VPORT_TYPE_IP6GRE:
          return "ip6gre";
  
      case OVS_VPORT_TYPE_UNSPEC:
      case __OVS_VPORT_TYPE_MAX:
          break;
      }
  
      VLOG_WARN_RL(&rl, "dp%d: port `%s' has unsupported type %u",
                   vport->dp_ifindex, vport->name, (unsigned int) vport->type);
      return "unknown";
  }
  
  enum ovs_vport_type
  netdev_to_ovs_vport_type(const char *type)
  {
      if (!strcmp(type, "tap") || !strcmp(type, "system")) {
          return OVS_VPORT_TYPE_NETDEV;
      } else if (!strcmp(type, "internal")) {
          return OVS_VPORT_TYPE_INTERNAL;
      } else if (strstr(type, "stt")) {
          return OVS_VPORT_TYPE_STT;
      } else if (!strcmp(type, "geneve")) {
          return OVS_VPORT_TYPE_GENEVE;
      } else if (!strcmp(type, "vxlan")) {
          return OVS_VPORT_TYPE_VXLAN;
      } else if (!strcmp(type, "lisp")) {
          return OVS_VPORT_TYPE_LISP;
      } else if (!strcmp(type, "erspan")) {
          return OVS_VPORT_TYPE_ERSPAN;
      } else if (!strcmp(type, "ip6erspan")) {
          return OVS_VPORT_TYPE_IP6ERSPAN;
      } else if (!strcmp(type, "ip6gre")) {
          return OVS_VPORT_TYPE_IP6GRE;
      } else if (!strcmp(type, "gre")) {
          return OVS_VPORT_TYPE_GRE;
      } else {
          return OVS_VPORT_TYPE_UNSPEC;
      }
  }
  
  static int
  dpif_netlink_port_add__(struct dpif_netlink *dpif, const char *name,
                          enum ovs_vport_type type,
                          struct ofpbuf *options,
                          odp_port_t *port_nop)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      struct dpif_netlink_vport request, reply;
      struct ofpbuf *buf;
      struct nl_sock *sock = NULL;
      uint32_t upcall_pids = 0;
      int error = 0;
  
      if (dpif->handlers) {
          error = create_nl_sock(dpif, &sock);
          if (error) {
              return error;
          }
      }
  
      dpif_netlink_vport_init(&request);
      request.cmd = OVS_VPORT_CMD_NEW;
      request.dp_ifindex = dpif->dp_ifindex;
      request.type = type;
      request.name = name;
  
      request.port_no = *port_nop;
      if (sock) {
          upcall_pids = nl_sock_pid(sock);
      }
      request.n_upcall_pids = 1;
      request.upcall_pids = &upcall_pids;
  
      if (options) {
          request.options = options->data;
          request.options_len = options->size;
      }
  
      error = dpif_netlink_vport_transact(&request, &reply, &buf);
      if (!error) {
          *port_nop = reply.port_no;
      } else {
          if (error == EBUSY && *port_nop != ODPP_NONE) {
              VLOG_INFO("%s: requested port %"PRIu32" is in use",
                        dpif_name(&dpif->dpif), *port_nop);
          }
  
          close_nl_sock(sock);
          goto exit;
      }
  
      error = vport_add_channel(dpif, *port_nop, sock);
      if (error) {
          VLOG_INFO("%s: could not add channel for port %s",
                      dpif_name(&dpif->dpif), name);
  
          /* Delete the port. */
          dpif_netlink_vport_init(&request);
          request.cmd = OVS_VPORT_CMD_DEL;
          request.dp_ifindex = dpif->dp_ifindex;
          request.port_no = *port_nop;
          dpif_netlink_vport_transact(&request, NULL, NULL);
          close_nl_sock(sock);
          goto exit;
      }
  
  exit:
      ofpbuf_delete(buf);
  
      return error;
  }
  
  static int
  dpif_netlink_port_add_compat(struct dpif_netlink *dpif, struct netdev *netdev,
                               odp_port_t *port_nop)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      const struct netdev_tunnel_config *tnl_cfg;
      char namebuf[NETDEV_VPORT_NAME_BUFSIZE];
      const char *type = netdev_get_type(netdev);
      uint64_t options_stub[64 / 8];
      enum ovs_vport_type ovs_type;
      struct ofpbuf options;
      const char *name;
  
      name = netdev_vport_get_dpif_port(netdev, namebuf, sizeof namebuf);
  
      ovs_type = netdev_to_ovs_vport_type(netdev_get_type(netdev));
      if (ovs_type == OVS_VPORT_TYPE_UNSPEC) {
          VLOG_WARN_RL(&error_rl, "%s: cannot create port `%s' because it has "
                       "unsupported type `%s'",
                       dpif_name(&dpif->dpif), name, type);
          return EINVAL;
      }
  
      if (ovs_type == OVS_VPORT_TYPE_NETDEV) {
  #ifdef _WIN32
          /* XXX : Map appropiate Windows handle */
  #else
          netdev_linux_ethtool_set_flag(netdev, ETH_FLAG_LRO, "LRO", false);
  #endif
      }
  
  #ifdef _WIN32
      if (ovs_type == OVS_VPORT_TYPE_INTERNAL) {
          if (!create_wmi_port(name)){
              VLOG_ERR("Could not create wmi internal port with name:%s", name);
              return EINVAL;
          };
      }
  #endif
  
      tnl_cfg = netdev_get_tunnel_config(netdev);
      if (tnl_cfg && (tnl_cfg->dst_port != 0 || tnl_cfg->exts)) {
          ofpbuf_use_stack(&options, options_stub, sizeof options_stub);
          if (tnl_cfg->dst_port) {
              nl_msg_put_u16(&options, OVS_TUNNEL_ATTR_DST_PORT,
                             ntohs(tnl_cfg->dst_port));
          }
          if (tnl_cfg->exts) {
              size_t ext_ofs;
              int i;
  
              ext_ofs = nl_msg_start_nested(&options, OVS_TUNNEL_ATTR_EXTENSION);
              for (i = 0; i < 32; i++) {
                  if (tnl_cfg->exts & (1 << i)) {
                      nl_msg_put_flag(&options, i);
                  }
              }
              nl_msg_end_nested(&options, ext_ofs);
          }
          return dpif_netlink_port_add__(dpif, name, ovs_type, &options,
                                         port_nop);
      } else {
          return dpif_netlink_port_add__(dpif, name, ovs_type, NULL, port_nop);
      }
  
  }
  
  static int
  dpif_netlink_rtnl_port_create_and_add(struct dpif_netlink *dpif,
                                        struct netdev *netdev,
                                        odp_port_t *port_nop)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
      char namebuf[NETDEV_VPORT_NAME_BUFSIZE];
      const char *name;
      int error;
  
      error = dpif_netlink_rtnl_port_create(netdev);
      if (error) {
          if (error != EOPNOTSUPP) {
              VLOG_WARN_RL(&rl, "Failed to create %s with rtnetlink: %s",
                           netdev_get_name(netdev), ovs_strerror(error));
          }
          return error;
      }
  
      name = netdev_vport_get_dpif_port(netdev, namebuf, sizeof namebuf);
      error = dpif_netlink_port_add__(dpif, name, OVS_VPORT_TYPE_NETDEV, NULL,
                                      port_nop);
      if (error) {
          dpif_netlink_rtnl_port_destroy(name, netdev_get_type(netdev));
      }
      return error;
  }
  
  static int
  dpif_netlink_port_add(struct dpif *dpif_, struct netdev *netdev,
                        odp_port_t *port_nop)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      int error = EOPNOTSUPP;
  
      fat_rwlock_wrlock(&dpif->upcall_lock);
      if (!ovs_tunnels_out_of_tree) {
          error = dpif_netlink_rtnl_port_create_and_add(dpif, netdev, port_nop);
      }
      if (error) {
          error = dpif_netlink_port_add_compat(dpif, netdev, port_nop);
      }
      fat_rwlock_unlock(&dpif->upcall_lock);
  
      return error;
  }
  
  static int
  dpif_netlink_port_del__(struct dpif_netlink *dpif, odp_port_t port_no)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      struct dpif_netlink_vport vport;
      struct dpif_port dpif_port;
      int error;
  
      error = dpif_netlink_port_query__(dpif, port_no, NULL, &dpif_port);
      if (error) {
          return error;
      }
  
      dpif_netlink_vport_init(&vport);
      vport.cmd = OVS_VPORT_CMD_DEL;
      vport.dp_ifindex = dpif->dp_ifindex;
      vport.port_no = port_no;
  #ifdef _WIN32
      if (!strcmp(dpif_port.type, "internal")) {
          if (!delete_wmi_port(dpif_port.name)) {
              VLOG_ERR("Could not delete wmi port with name: %s",
                       dpif_port.name);
          };
      }
  #endif
      error = dpif_netlink_vport_transact(&vport, NULL, NULL);
  
      vport_del_channels(dpif, port_no);
  
      if (!error && !ovs_tunnels_out_of_tree) {
          error = dpif_netlink_rtnl_port_destroy(dpif_port.name, dpif_port.type);
          if (error == EOPNOTSUPP) {
              error = 0;
          }
      }
  
      dpif_port_destroy(&dpif_port);
  
      return error;
  }
  
  static int
  dpif_netlink_port_del(struct dpif *dpif_, odp_port_t port_no)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      int error;
  
      fat_rwlock_wrlock(&dpif->upcall_lock);
      error = dpif_netlink_port_del__(dpif, port_no);
      fat_rwlock_unlock(&dpif->upcall_lock);
  
      return error;
  }
  
  static int
  dpif_netlink_port_query__(const struct dpif_netlink *dpif, odp_port_t port_no,
                            const char *port_name, struct dpif_port *dpif_port)
  {
      struct dpif_netlink_vport request;
      struct dpif_netlink_vport reply;
      struct ofpbuf *buf;
      int error;
  
      dpif_netlink_vport_init(&request);
      request.cmd = OVS_VPORT_CMD_GET;
      request.dp_ifindex = dpif->dp_ifindex;
      request.port_no = port_no;
      request.name = port_name;
  
      error = dpif_netlink_vport_transact(&request, &reply, &buf);
      if (!error) {
          if (reply.dp_ifindex != request.dp_ifindex) {
              /* A query by name reported that 'port_name' is in some datapath
               * other than 'dpif', but the caller wants to know about 'dpif'. */
              error = ENODEV;
          } else if (dpif_port) {
              dpif_port->name = xstrdup(reply.name);
              dpif_port->type = xstrdup(get_vport_type(&reply));
              dpif_port->port_no = reply.port_no;
          }
          ofpbuf_delete(buf);
      }
      return error;
  }
  
  static int
  dpif_netlink_port_query_by_number(const struct dpif *dpif_, odp_port_t port_no,
                                    struct dpif_port *dpif_port)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
  
      return dpif_netlink_port_query__(dpif, port_no, NULL, dpif_port);
  }
  
  static int
  dpif_netlink_port_query_by_name(const struct dpif *dpif_, const char *devname,
                                struct dpif_port *dpif_port)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
  
      return dpif_netlink_port_query__(dpif, 0, devname, dpif_port);
  }
  
  static uint32_t
  dpif_netlink_port_get_pid__(const struct dpif_netlink *dpif,
                              odp_port_t port_no)
      OVS_REQ_RDLOCK(dpif->upcall_lock)
  {
      uint32_t port_idx = odp_to_u32(port_no);
      uint32_t pid = 0;
  
      if (dpif->handlers && dpif->uc_array_size > 0) {
          /* The ODPP_NONE "reserved" port number uses the "ovs-system"'s
           * channel, since it is not heavily loaded. */
          uint32_t idx = port_idx >= dpif->uc_array_size ? 0 : port_idx;
  
          /* Needs to check in case the socket pointer is changed in between
           * the holding of upcall_lock.  A known case happens when the main
           * thread deletes the vport while the handler thread is handling
           * the upcall from that port. */
          if (dpif->channels[idx].sock) {
              pid = nl_sock_pid(dpif->channels[idx].sock);
          }
      }
  
      return pid;
  }
  
  static uint32_t
  dpif_netlink_port_get_pid(const struct dpif *dpif_, odp_port_t port_no)
  {
      const struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      uint32_t ret;
  
      fat_rwlock_rdlock(&dpif->upcall_lock);
      ret = dpif_netlink_port_get_pid__(dpif, port_no);
      fat_rwlock_unlock(&dpif->upcall_lock);
  
      return ret;
  }
  
  static int
  dpif_netlink_flow_flush(struct dpif *dpif_)
  {
      const struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct dpif_netlink_flow flow;
  
      dpif_netlink_flow_init(&flow);
      flow.cmd = OVS_FLOW_CMD_DEL;
      flow.dp_ifindex = dpif->dp_ifindex;
  
      if (netdev_is_flow_api_enabled()) {
          netdev_ports_flow_flush(dpif_->dpif_class);
      }
  
      return dpif_netlink_flow_transact(&flow, NULL, NULL);
  }
  
  struct dpif_netlink_port_state {
      struct nl_dump dump;
      struct ofpbuf buf;
  };
  
  static void
  dpif_netlink_port_dump_start__(const struct dpif_netlink *dpif,
                                 struct nl_dump *dump)
  {
      struct dpif_netlink_vport request;
      struct ofpbuf *buf;
  
      dpif_netlink_vport_init(&request);
      request.cmd = OVS_VPORT_CMD_GET;
      request.dp_ifindex = dpif->dp_ifindex;
  
      buf = ofpbuf_new(1024);
      dpif_netlink_vport_to_ofpbuf(&request, buf);
      nl_dump_start(dump, NETLINK_GENERIC, buf);
      ofpbuf_delete(buf);
  }
  
  static int
  dpif_netlink_port_dump_start(const struct dpif *dpif_, void **statep)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct dpif_netlink_port_state *state;
  
      *statep = state = xmalloc(sizeof *state);
      dpif_netlink_port_dump_start__(dpif, &state->dump);
  
      ofpbuf_init(&state->buf, NL_DUMP_BUFSIZE);
      return 0;
  }
  
  static int
  dpif_netlink_port_dump_next__(const struct dpif_netlink *dpif,
                                struct nl_dump *dump,
                                struct dpif_netlink_vport *vport,
                                struct ofpbuf *buffer)
  {
      struct ofpbuf buf;
      int error;
  
      if (!nl_dump_next(dump, &buf, buffer)) {
          return EOF;
      }
  
      error = dpif_netlink_vport_from_ofpbuf(vport, &buf);
      if (error) {
          VLOG_WARN_RL(&error_rl, "%s: failed to parse vport record (%s)",
                       dpif_name(&dpif->dpif), ovs_strerror(error));
      }
      return error;
  }
  
  static int
  dpif_netlink_port_dump_next(const struct dpif *dpif_, void *state_,
                              struct dpif_port *dpif_port)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct dpif_netlink_port_state *state = state_;
      struct dpif_netlink_vport vport;
      int error;
  
      error = dpif_netlink_port_dump_next__(dpif, &state->dump, &vport,
                                            &state->buf);
      if (error) {
          return error;
      }
      dpif_port->name = CONST_CAST(char *, vport.name);
      dpif_port->type = CONST_CAST(char *, get_vport_type(&vport));
      dpif_port->port_no = vport.port_no;
      return 0;
  }
  
  static int
  dpif_netlink_port_dump_done(const struct dpif *dpif_ OVS_UNUSED, void *state_)
  {
      struct dpif_netlink_port_state *state = state_;
      int error = nl_dump_done(&state->dump);
  
      ofpbuf_uninit(&state->buf);
      free(state);
      return error;
  }
  
  static int
  dpif_netlink_port_poll(const struct dpif *dpif_, char **devnamep)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
  
      /* Lazily create the Netlink socket to listen for notifications. */
      if (!dpif->port_notifier) {
          struct nl_sock *sock;
          int error;
  
          error = nl_sock_create(NETLINK_GENERIC, &sock);
          if (error) {
              return error;
          }
  
          error = nl_sock_join_mcgroup(sock, ovs_vport_mcgroup);
          if (error) {
              nl_sock_destroy(sock);
              return error;
          }
          dpif->port_notifier = sock;
  
          /* We have no idea of the current state so report that everything
           * changed. */
          return ENOBUFS;
      }
  
      for (;;) {
          static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
          uint64_t buf_stub[4096 / 8];
          struct ofpbuf buf;
          int error;
  
          ofpbuf_use_stub(&buf, buf_stub, sizeof buf_stub);
          error = nl_sock_recv(dpif->port_notifier, &buf, NULL, false);
          if (!error) {
              struct dpif_netlink_vport vport;
  
              error = dpif_netlink_vport_from_ofpbuf(&vport, &buf);
              if (!error) {
                  if (vport.dp_ifindex == dpif->dp_ifindex
                      && (vport.cmd == OVS_VPORT_CMD_NEW
                          || vport.cmd == OVS_VPORT_CMD_DEL
                          || vport.cmd == OVS_VPORT_CMD_SET)) {
                      VLOG_DBG("port_changed: dpif:%s vport:%s cmd:%"PRIu8,
                               dpif->dpif.full_name, vport.name, vport.cmd);
                      if (vport.cmd == OVS_VPORT_CMD_DEL && dpif->handlers) {
                          dpif->refresh_channels = true;
                      }
                      *devnamep = xstrdup(vport.name);
                      ofpbuf_uninit(&buf);
                      return 0;
                  }
              }
          } else if (error != EAGAIN) {
              VLOG_WARN_RL(&rl, "error reading or parsing netlink (%s)",
                           ovs_strerror(error));
              nl_sock_drain(dpif->port_notifier);
              error = ENOBUFS;
          }
  
          ofpbuf_uninit(&buf);
          if (error) {
              return error;
          }
      }
  }
  
  static void
  dpif_netlink_port_poll_wait(const struct dpif *dpif_)
  {
      const struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
  
      if (dpif->port_notifier) {
          nl_sock_wait(dpif->port_notifier, POLLIN);
      } else {
          poll_immediate_wake();
      }
  }
  
  static void
  dpif_netlink_flow_init_ufid(struct dpif_netlink_flow *request,
                              const ovs_u128 *ufid, bool terse)
  {
      if (ufid) {
          request->ufid = *ufid;
          request->ufid_present = true;
      } else {
          request->ufid_present = false;
      }
      request->ufid_terse = terse;
  }
  
  static void
  dpif_netlink_init_flow_get__(const struct dpif_netlink *dpif,
                               const struct nlattr *key, size_t key_len,
                               const ovs_u128 *ufid, bool terse,
                               struct dpif_netlink_flow *request)
  {
      dpif_netlink_flow_init(request);
      request->cmd = OVS_FLOW_CMD_GET;
      request->dp_ifindex = dpif->dp_ifindex;
      request->key = key;
      request->key_len = key_len;
      dpif_netlink_flow_init_ufid(request, ufid, terse);
  }
  
  static void
  dpif_netlink_init_flow_get(const struct dpif_netlink *dpif,
                             const struct dpif_flow_get *get,
                             struct dpif_netlink_flow *request)
  {
      dpif_netlink_init_flow_get__(dpif, get->key, get->key_len, get->ufid,
                                   false, request);
  }
  
  static int
  dpif_netlink_flow_get__(const struct dpif_netlink *dpif,
                          const struct nlattr *key, size_t key_len,
                          const ovs_u128 *ufid, bool terse,
                          struct dpif_netlink_flow *reply, struct ofpbuf **bufp)
  {
      struct dpif_netlink_flow request;
  
      dpif_netlink_init_flow_get__(dpif, key, key_len, ufid, terse, &request);
      return dpif_netlink_flow_transact(&request, reply, bufp);
  }
  
  static int
  dpif_netlink_flow_get(const struct dpif_netlink *dpif,
                        const struct dpif_netlink_flow *flow,
                        struct dpif_netlink_flow *reply, struct ofpbuf **bufp)
  {
      return dpif_netlink_flow_get__(dpif, flow->key, flow->key_len,
                                     flow->ufid_present ? &flow->ufid : NULL,
                                     false, reply, bufp);
  }
  
  static void
  dpif_netlink_init_flow_put(struct dpif_netlink *dpif,
                             const struct dpif_flow_put *put,
                             struct dpif_netlink_flow *request)
  {
      static const struct nlattr dummy_action;
  
      dpif_netlink_flow_init(request);
      request->cmd = (put->flags & DPIF_FP_CREATE
                      ? OVS_FLOW_CMD_NEW : OVS_FLOW_CMD_SET);
      request->dp_ifindex = dpif->dp_ifindex;
      request->key = put->key;
      request->key_len = put->key_len;
      request->mask = put->mask;
      request->mask_len = put->mask_len;
      dpif_netlink_flow_init_ufid(request, put->ufid, false);
  
      /* Ensure that OVS_FLOW_ATTR_ACTIONS will always be included. */
      request->actions = (put->actions
                          ? put->actions
                          : CONST_CAST(struct nlattr *, &dummy_action));
      request->actions_len = put->actions_len;
      if (put->flags & DPIF_FP_ZERO_STATS) {
          request->clear = true;
      }
      if (put->flags & DPIF_FP_PROBE) {
          request->probe = true;
      }
      request->nlmsg_flags = put->flags & DPIF_FP_MODIFY ? 0 : NLM_F_CREATE;
  }
  
  static void
  dpif_netlink_init_flow_del__(struct dpif_netlink *dpif,
                               const struct nlattr *key, size_t key_len,
                               const ovs_u128 *ufid, bool terse,
                               struct dpif_netlink_flow *request)
  {
      dpif_netlink_flow_init(request);
      request->cmd = OVS_FLOW_CMD_DEL;
      request->dp_ifindex = dpif->dp_ifindex;
      request->key = key;
      request->key_len = key_len;
      dpif_netlink_flow_init_ufid(request, ufid, terse);
  }
  
  static void
  dpif_netlink_init_flow_del(struct dpif_netlink *dpif,
                             const struct dpif_flow_del *del,
                             struct dpif_netlink_flow *request)
  {
      dpif_netlink_init_flow_del__(dpif, del->key, del->key_len,
                                   del->ufid, del->terse, request);
  }
  
  struct dpif_netlink_flow_dump {
      struct dpif_flow_dump up;
      struct nl_dump nl_dump;
      atomic_int status;
      struct netdev_flow_dump **netdev_dumps;
      int netdev_dumps_num;                    /* Number of netdev_flow_dumps */
      struct ovs_mutex netdev_lock;            /* Guards the following. */
      int netdev_current_dump OVS_GUARDED;     /* Shared current dump */
      struct dpif_flow_dump_types types;       /* Type of dump */
  };
  
  static struct dpif_netlink_flow_dump *
  dpif_netlink_flow_dump_cast(struct dpif_flow_dump *dump)
  {
      return CONTAINER_OF(dump, struct dpif_netlink_flow_dump, up);
  }
  
  static void
  start_netdev_dump(const struct dpif *dpif_,
                    struct dpif_netlink_flow_dump *dump)
  {
      ovs_mutex_init(&dump->netdev_lock);
  
      if (!(dump->types.netdev_flows)) {
          dump->netdev_dumps_num = 0;
          dump->netdev_dumps = NULL;
          return;
      }
  
      ovs_mutex_lock(&dump->netdev_lock);
      dump->netdev_current_dump = 0;
      dump->netdev_dumps
          = netdev_ports_flow_dump_create(dpif_->dpif_class,
                                          &dump->netdev_dumps_num);
      ovs_mutex_unlock(&dump->netdev_lock);
  }
  
  static void
  dpif_netlink_populate_flow_dump_types(struct dpif_netlink_flow_dump *dump,
                                        struct dpif_flow_dump_types *types)
  {
      if (!types) {
          dump->types.ovs_flows = true;
          dump->types.netdev_flows = true;
      } else {
          memcpy(&dump->types, types, sizeof *types);
      }
  }
  
  static struct dpif_flow_dump *
  dpif_netlink_flow_dump_create(const struct dpif *dpif_, bool terse,
                                struct dpif_flow_dump_types *types)
  {
      const struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct dpif_netlink_flow_dump *dump;
      struct dpif_netlink_flow request;
      struct ofpbuf *buf;
  
      dump = xmalloc(sizeof *dump);
      dpif_flow_dump_init(&dump->up, dpif_);
  
      dpif_netlink_populate_flow_dump_types(dump, types);
  
      if (dump->types.ovs_flows) {
          dpif_netlink_flow_init(&request);
          request.cmd = OVS_FLOW_CMD_GET;
          request.dp_ifindex = dpif->dp_ifindex;
          request.ufid_present = false;
          request.ufid_terse = terse;
  
          buf = ofpbuf_new(1024);
          dpif_netlink_flow_to_ofpbuf(&request, buf);
          nl_dump_start(&dump->nl_dump, NETLINK_GENERIC, buf);
          ofpbuf_delete(buf);
      }
      atomic_init(&dump->status, 0);
      dump->up.terse = terse;
  
      start_netdev_dump(dpif_, dump);
  
      return &dump->up;
  }
  
  static int
  dpif_netlink_flow_dump_destroy(struct dpif_flow_dump *dump_)
  {
      struct dpif_netlink_flow_dump *dump = dpif_netlink_flow_dump_cast(dump_);
      unsigned int nl_status = 0;
      int dump_status;
  
      if (dump->types.ovs_flows) {
          nl_status = nl_dump_done(&dump->nl_dump);
      }
  
      for (int i = 0; i < dump->netdev_dumps_num; i++) {
          int err = netdev_flow_dump_destroy(dump->netdev_dumps[i]);
  
          if (err != 0 && err != EOPNOTSUPP) {
              VLOG_ERR("failed dumping netdev: %s", ovs_strerror(err));
          }
      }
  
      free(dump->netdev_dumps);
      ovs_mutex_destroy(&dump->netdev_lock);
  
      /* No other thread has access to 'dump' at this point. */
      atomic_read_relaxed(&dump->status, &dump_status);
      free(dump);
      return dump_status ? dump_status : nl_status;
  }
  
  struct dpif_netlink_flow_dump_thread {
      struct dpif_flow_dump_thread up;
      struct dpif_netlink_flow_dump *dump;
      struct dpif_netlink_flow flow;
      struct dpif_flow_stats stats;
      struct ofpbuf nl_flows;     /* Always used to store flows. */
      struct ofpbuf *nl_actions;  /* Used if kernel does not supply actions. */
      int netdev_dump_idx;        /* This thread current netdev dump index */
      bool netdev_done;           /* If we are finished dumping netdevs */
  
      /* (Key/Mask/Actions) Buffers for netdev dumping */
      struct odputil_keybuf keybuf[FLOW_DUMP_MAX_BATCH];
      struct odputil_keybuf maskbuf[FLOW_DUMP_MAX_BATCH];
      struct odputil_keybuf actbuf[FLOW_DUMP_MAX_BATCH];
  };
  
  static struct dpif_netlink_flow_dump_thread *
  dpif_netlink_flow_dump_thread_cast(struct dpif_flow_dump_thread *thread)
  {
      return CONTAINER_OF(thread, struct dpif_netlink_flow_dump_thread, up);
  }
  
  static struct dpif_flow_dump_thread *
  dpif_netlink_flow_dump_thread_create(struct dpif_flow_dump *dump_)
  {
      struct dpif_netlink_flow_dump *dump = dpif_netlink_flow_dump_cast(dump_);
      struct dpif_netlink_flow_dump_thread *thread;
  
      thread = xmalloc(sizeof *thread);
      dpif_flow_dump_thread_init(&thread->up, &dump->up);
      thread->dump = dump;
      ofpbuf_init(&thread->nl_flows, NL_DUMP_BUFSIZE);
      thread->nl_actions = NULL;
      thread->netdev_dump_idx = 0;
      thread->netdev_done = !(thread->netdev_dump_idx < dump->netdev_dumps_num);
  
      return &thread->up;
  }
  
  static void
  dpif_netlink_flow_dump_thread_destroy(struct dpif_flow_dump_thread *thread_)
  {
      struct dpif_netlink_flow_dump_thread *thread
          = dpif_netlink_flow_dump_thread_cast(thread_);
  
      ofpbuf_uninit(&thread->nl_flows);
      ofpbuf_delete(thread->nl_actions);
      free(thread);
  }
  
  static void
  dpif_netlink_flow_to_dpif_flow(struct dpif *dpif, struct dpif_flow *dpif_flow,
                                 const struct dpif_netlink_flow *datapath_flow)
  {
      dpif_flow->key = datapath_flow->key;
      dpif_flow->key_len = datapath_flow->key_len;
      dpif_flow->mask = datapath_flow->mask;
      dpif_flow->mask_len = datapath_flow->mask_len;
      dpif_flow->actions = datapath_flow->actions;
      dpif_flow->actions_len = datapath_flow->actions_len;
      dpif_flow->ufid_present = datapath_flow->ufid_present;
      dpif_flow->pmd_id = PMD_ID_NULL;
      if (datapath_flow->ufid_present) {
          dpif_flow->ufid = datapath_flow->ufid;
      } else {
          ovs_assert(datapath_flow->key && datapath_flow->key_len);
          dpif_flow_hash(dpif, datapath_flow->key, datapath_flow->key_len,
                         &dpif_flow->ufid);
      }
      dpif_netlink_flow_get_stats(datapath_flow, &dpif_flow->stats);
      dpif_flow->attrs.offloaded = false;
      dpif_flow->attrs.dp_layer = "ovs";
  }
  
  /* The design is such that all threads are working together on the first dump
   * to the last, in order (at first they all on dump 0).
   * When the first thread finds that the given dump is finished,
   * they all move to the next. If two or more threads find the same dump
   * is finished at the same time, the first one will advance the shared
   * netdev_current_dump and the others will catch up. */
  static void
  dpif_netlink_advance_netdev_dump(struct dpif_netlink_flow_dump_thread *thread)
  {
      struct dpif_netlink_flow_dump *dump = thread->dump;
  
      ovs_mutex_lock(&dump->netdev_lock);
      /* if we haven't finished (dumped everything) */
      if (dump->netdev_current_dump < dump->netdev_dumps_num) {
          /* if we are the first to find that current dump is finished
           * advance it. */
          if (thread->netdev_dump_idx == dump->netdev_current_dump) {
              thread->netdev_dump_idx = ++dump->netdev_current_dump;
              /* did we just finish the last dump? done. */
              if (dump->netdev_current_dump == dump->netdev_dumps_num) {
                  thread->netdev_done = true;
              }
          } else {
              /* otherwise, we are behind, catch up */
              thread->netdev_dump_idx = dump->netdev_current_dump;
          }
      } else {
          /* some other thread finished */
          thread->netdev_done = true;
      }
      ovs_mutex_unlock(&dump->netdev_lock);
  }
  
  static int
  dpif_netlink_netdev_match_to_dpif_flow(struct match *match,
                                         struct ofpbuf *key_buf,
                                         struct ofpbuf *mask_buf,
                                         struct nlattr *actions,
                                         struct dpif_flow_stats *stats,
                                         struct dpif_flow_attrs *attrs,
                                         ovs_u128 *ufid,
                                         struct dpif_flow *flow,
                                         bool terse OVS_UNUSED)
  {
  
      struct odp_flow_key_parms odp_parms = {
          .flow = &match->flow,
          .mask = &match->wc.masks,
          .support = {
              .max_vlan_headers = 2,
          },
      };
      size_t offset;
  
      memset(flow, 0, sizeof *flow);
  
      /* Key */
      offset = key_buf->size;
      flow->key = ofpbuf_tail(key_buf);
      odp_flow_key_from_flow(&odp_parms, key_buf);
      flow->key_len = key_buf->size - offset;
  
      /* Mask */
      offset = mask_buf->size;
      flow->mask = ofpbuf_tail(mask_buf);
      odp_parms.key_buf = key_buf;
      odp_flow_key_from_mask(&odp_parms, mask_buf);
      flow->mask_len = mask_buf->size - offset;
  
      /* Actions */
      flow->actions = nl_attr_get(actions);
      flow->actions_len = nl_attr_get_size(actions);
  
      /* Stats */
      memcpy(&flow->stats, stats, sizeof *stats);
  
      /* UFID */
      flow->ufid_present = true;
      flow->ufid = *ufid;
  
      flow->pmd_id = PMD_ID_NULL;
  
      memcpy(&flow->attrs, attrs, sizeof *attrs);
  
      return 0;
  }
  
  static int
  dpif_netlink_flow_dump_next(struct dpif_flow_dump_thread *thread_,
                              struct dpif_flow *flows, int max_flows)
  {
      struct dpif_netlink_flow_dump_thread *thread
          = dpif_netlink_flow_dump_thread_cast(thread_);
      struct dpif_netlink_flow_dump *dump = thread->dump;
      struct dpif_netlink *dpif = dpif_netlink_cast(thread->up.dpif);
      int n_flows;
  
      ofpbuf_delete(thread->nl_actions);
      thread->nl_actions = NULL;
  
      n_flows = 0;
      max_flows = MIN(max_flows, FLOW_DUMP_MAX_BATCH);
  
      while (!thread->netdev_done && n_flows < max_flows) {
          struct odputil_keybuf *maskbuf = &thread->maskbuf[n_flows];
          struct odputil_keybuf *keybuf = &thread->keybuf[n_flows];
          struct odputil_keybuf *actbuf = &thread->actbuf[n_flows];
          struct ofpbuf key, mask, act;
          struct dpif_flow *f = &flows[n_flows];
          int cur = thread->netdev_dump_idx;
          struct netdev_flow_dump *netdev_dump = dump->netdev_dumps[cur];
          struct match match;
          struct nlattr *actions;
          struct dpif_flow_stats stats;
          struct dpif_flow_attrs attrs;
          ovs_u128 ufid;
          bool has_next;
  
          ofpbuf_use_stack(&key, keybuf, sizeof *keybuf);
          ofpbuf_use_stack(&act, actbuf, sizeof *actbuf);
          ofpbuf_use_stack(&mask, maskbuf, sizeof *maskbuf);
          has_next = netdev_flow_dump_next(netdev_dump, &match,
                                          &actions, &stats, &attrs,
                                          &ufid,
                                          &thread->nl_flows,
                                          &act);
          if (has_next) {
              dpif_netlink_netdev_match_to_dpif_flow(&match,
                                                     &key, &mask,
                                                     actions,
                                                     &stats,
                                                     &attrs,
                                                     &ufid,
                                                     f,
                                                     dump->up.terse);
              n_flows++;
          } else {
              dpif_netlink_advance_netdev_dump(thread);
          }
      }
  
      if (!(dump->types.ovs_flows)) {
          return n_flows;
      }
  
      while (!n_flows
             || (n_flows < max_flows && thread->nl_flows.size)) {
          struct dpif_netlink_flow datapath_flow;
          struct ofpbuf nl_flow;
          int error;
  
          /* Try to grab another flow. */
          if (!nl_dump_next(&dump->nl_dump, &nl_flow, &thread->nl_flows)) {
              break;
          }
  
          /* Convert the flow to our output format. */
          error = dpif_netlink_flow_from_ofpbuf(&datapath_flow, &nl_flow);
          if (error) {
              atomic_store_relaxed(&dump->status, error);
              break;
          }
  
          if (dump->up.terse || datapath_flow.actions) {
              /* Common case: we don't want actions, or the flow includes
               * actions. */
              dpif_netlink_flow_to_dpif_flow(&dpif->dpif, &flows[n_flows++],
                                             &datapath_flow);
          } else {
              /* Rare case: the flow does not include actions.  Retrieve this
               * individual flow again to get the actions. */
              error = dpif_netlink_flow_get(dpif, &datapath_flow,
                                            &datapath_flow, &thread->nl_actions);
              if (error == ENOENT) {
                  VLOG_DBG("dumped flow disappeared on get");
                  continue;
              } else if (error) {
                  VLOG_WARN("error fetching dumped flow: %s",
                            ovs_strerror(error));
                  atomic_store_relaxed(&dump->status, error);
                  break;
              }
  
              /* Save this flow.  Then exit, because we only have one buffer to
               * handle this case. */
              dpif_netlink_flow_to_dpif_flow(&dpif->dpif, &flows[n_flows++],
                                             &datapath_flow);
              break;
          }
      }
      return n_flows;
  }
  
  static void
  dpif_netlink_encode_execute(int dp_ifindex, const struct dpif_execute *d_exec,
                              struct ofpbuf *buf)
  {
      struct ovs_header *k_exec;
      size_t key_ofs;
  
      ofpbuf_prealloc_tailroom(buf, (64
                                     + dp_packet_size(d_exec->packet)
                                     + ODP_KEY_METADATA_SIZE
                                     + d_exec->actions_len));
  
      nl_msg_put_genlmsghdr(buf, 0, ovs_packet_family, NLM_F_REQUEST,
                            OVS_PACKET_CMD_EXECUTE, OVS_PACKET_VERSION);
  
      k_exec = ofpbuf_put_uninit(buf, sizeof *k_exec);
      k_exec->dp_ifindex = dp_ifindex;
  
      nl_msg_put_unspec(buf, OVS_PACKET_ATTR_PACKET,
                        dp_packet_data(d_exec->packet),
                        dp_packet_size(d_exec->packet));
  
      key_ofs = nl_msg_start_nested(buf, OVS_PACKET_ATTR_KEY);
      odp_key_from_dp_packet(buf, d_exec->packet);
      nl_msg_end_nested(buf, key_ofs);
  
      nl_msg_put_unspec(buf, OVS_PACKET_ATTR_ACTIONS,
                        d_exec->actions, d_exec->actions_len);
      if (d_exec->probe) {
          nl_msg_put_flag(buf, OVS_PACKET_ATTR_PROBE);
      }
      if (d_exec->mtu) {
          nl_msg_put_u16(buf, OVS_PACKET_ATTR_MRU, d_exec->mtu);
      }
  }
  
  /* Executes, against 'dpif', up to the first 'n_ops' operations in 'ops'.
   * Returns the number actually executed (at least 1, if 'n_ops' is
   * positive). */
  static size_t
  dpif_netlink_operate__(struct dpif_netlink *dpif,
                         struct dpif_op **ops, size_t n_ops)
  {
      struct op_auxdata {
          struct nl_transaction txn;
  
          struct ofpbuf request;
          uint64_t request_stub[1024 / 8];
  
          struct ofpbuf reply;
          uint64_t reply_stub[1024 / 8];
      } auxes[OPERATE_MAX_OPS];
  
      struct nl_transaction *txnsp[OPERATE_MAX_OPS];
      size_t i;
  
      n_ops = MIN(n_ops, OPERATE_MAX_OPS);
      for (i = 0; i < n_ops; i++) {
          struct op_auxdata *aux = &auxes[i];
          struct dpif_op *op = ops[i];
          struct dpif_flow_put *put;
          struct dpif_flow_del *del;
          struct dpif_flow_get *get;
          struct dpif_netlink_flow flow;
  
          ofpbuf_use_stub(&aux->request,
                          aux->request_stub, sizeof aux->request_stub);
          aux->txn.request = &aux->request;
  
          ofpbuf_use_stub(&aux->reply, aux->reply_stub, sizeof aux->reply_stub);
          aux->txn.reply = NULL;
  
          switch (op->type) {
          case DPIF_OP_FLOW_PUT:
              put = &op->flow_put;
              dpif_netlink_init_flow_put(dpif, put, &flow);
              if (put->stats) {
                  flow.nlmsg_flags |= NLM_F_ECHO;
                  aux->txn.reply = &aux->reply;
              }
              dpif_netlink_flow_to_ofpbuf(&flow, &aux->request);
              break;
  
          case DPIF_OP_FLOW_DEL:
              del = &op->flow_del;
              dpif_netlink_init_flow_del(dpif, del, &flow);
              if (del->stats) {
                  flow.nlmsg_flags |= NLM_F_ECHO;
                  aux->txn.reply = &aux->reply;
              }
              dpif_netlink_flow_to_ofpbuf(&flow, &aux->request);
              break;
  
          case DPIF_OP_EXECUTE:
              /* Can't execute a packet that won't fit in a Netlink attribute. */
              if (OVS_UNLIKELY(nl_attr_oversized(
                                   dp_packet_size(op->execute.packet)))) {
                  /* Report an error immediately if this is the first operation.
                   * Otherwise the easiest thing to do is to postpone to the next
                   * call (when this will be the first operation). */
                  if (i == 0) {
                      VLOG_ERR_RL(&error_rl,
                                  "dropping oversized %"PRIu32"-byte packet",
                                  dp_packet_size(op->execute.packet));
                      op->error = ENOBUFS;
                      return 1;
                  }
                  n_ops = i;
              } else {
                  dpif_netlink_encode_execute(dpif->dp_ifindex, &op->execute,
                                              &aux->request);
              }
              break;
  
          case DPIF_OP_FLOW_GET:
              get = &op->flow_get;
              dpif_netlink_init_flow_get(dpif, get, &flow);
              aux->txn.reply = get->buffer;
              dpif_netlink_flow_to_ofpbuf(&flow, &aux->request);
              break;
  
          default:
              OVS_NOT_REACHED();
          }
      }
  
      for (i = 0; i < n_ops; i++) {
          txnsp[i] = &auxes[i].txn;
      }
      nl_transact_multiple(NETLINK_GENERIC, txnsp, n_ops);
  
      for (i = 0; i < n_ops; i++) {
          struct op_auxdata *aux = &auxes[i];
          struct nl_transaction *txn = &auxes[i].txn;
          struct dpif_op *op = ops[i];
          struct dpif_flow_put *put;
          struct dpif_flow_del *del;
          struct dpif_flow_get *get;
  
          op->error = txn->error;
  
          switch (op->type) {
          case DPIF_OP_FLOW_PUT:
              put = &op->flow_put;
              if (put->stats) {
                  if (!op->error) {
                      struct dpif_netlink_flow reply;
  
                      op->error = dpif_netlink_flow_from_ofpbuf(&reply,
                                                                txn->reply);
                      if (!op->error) {
                          dpif_netlink_flow_get_stats(&reply, put->stats);
                      }
                  }
              }
              break;
  
          case DPIF_OP_FLOW_DEL:
              del = &op->flow_del;
              if (del->stats) {
                  if (!op->error) {
                      struct dpif_netlink_flow reply;
  
                      op->error = dpif_netlink_flow_from_ofpbuf(&reply,
                                                                txn->reply);
                      if (!op->error) {
                          dpif_netlink_flow_get_stats(&reply, del->stats);
                      }
                  }
              }
              break;
  
          case DPIF_OP_EXECUTE:
              break;
  
          case DPIF_OP_FLOW_GET:
              get = &op->flow_get;
              if (!op->error) {
                  struct dpif_netlink_flow reply;
  
                  op->error = dpif_netlink_flow_from_ofpbuf(&reply, txn->reply);
                  if (!op->error) {
                      dpif_netlink_flow_to_dpif_flow(&dpif->dpif, get->flow,
                                                     &reply);
                  }
              }
              break;
  
          default:
              OVS_NOT_REACHED();
          }
  
          ofpbuf_uninit(&aux->request);
          ofpbuf_uninit(&aux->reply);
      }
  
      return n_ops;
  }
  
  static int
  parse_flow_get(struct dpif_netlink *dpif, struct dpif_flow_get *get)
  {
      struct dpif_flow *dpif_flow = get->flow;
      struct match match;
      struct nlattr *actions;
      struct dpif_flow_stats stats;
      struct dpif_flow_attrs attrs;
      struct ofpbuf buf;
      uint64_t act_buf[1024 / 8];
      struct odputil_keybuf maskbuf;
      struct odputil_keybuf keybuf;
      struct odputil_keybuf actbuf;
      struct ofpbuf key, mask, act;
      int err;
  
      ofpbuf_use_stack(&buf, &act_buf, sizeof act_buf);
      err = netdev_ports_flow_get(dpif->dpif.dpif_class, &match,
                                  &actions, get->ufid, &stats, &attrs, &buf);
      if (err) {
          return err;
      }
  
      VLOG_DBG("found flow from netdev, translating to dpif flow");
  
      ofpbuf_use_stack(&key, &keybuf, sizeof keybuf);
      ofpbuf_use_stack(&act, &actbuf, sizeof actbuf);
      ofpbuf_use_stack(&mask, &maskbuf, sizeof maskbuf);
      dpif_netlink_netdev_match_to_dpif_flow(&match, &key, &mask, actions,
                                             &stats, &attrs,
                                             (ovs_u128 *) get->ufid,
                                             dpif_flow,
                                             false);
      ofpbuf_put(get->buffer, nl_attr_get(actions), nl_attr_get_size(actions));
      dpif_flow->actions = ofpbuf_at(get->buffer, 0, 0);
      dpif_flow->actions_len = nl_attr_get_size(actions);
  
      return 0;
  }
  
  static int
  parse_flow_put(struct dpif_netlink *dpif, struct dpif_flow_put *put)
  {
      static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
      const struct dpif_class *dpif_class = dpif->dpif.dpif_class;
      struct match match;
      odp_port_t in_port;
      const struct nlattr *nla;
      size_t left;
      struct netdev *dev;
      struct offload_info info;
      ovs_be16 dst_port = 0;
      uint8_t csum_on = false;
      int err;
  
      if (put->flags & DPIF_FP_PROBE) {
          return EOPNOTSUPP;
      }
  
      err = parse_key_and_mask_to_match(put->key, put->key_len, put->mask,
                                        put->mask_len, &match);
      if (err) {
          return err;
      }
  
      in_port = match.flow.in_port.odp_port;
      dev = netdev_ports_get(in_port, dpif_class);
      if (!dev) {
          return EOPNOTSUPP;
      }
  
      /* Get tunnel dst port */
      NL_ATTR_FOR_EACH(nla, left, put->actions, put->actions_len) {
          if (nl_attr_type(nla) == OVS_ACTION_ATTR_OUTPUT) {
              const struct netdev_tunnel_config *tnl_cfg;
              struct netdev *outdev;
              odp_port_t out_port;
  
              out_port = nl_attr_get_odp_port(nla);
              outdev = netdev_ports_get(out_port, dpif_class);
              if (!outdev) {
                  err = EOPNOTSUPP;
                  goto out;
              }
              tnl_cfg = netdev_get_tunnel_config(outdev);
              if (tnl_cfg && tnl_cfg->dst_port != 0) {
                  dst_port = tnl_cfg->dst_port;
              }
              if (tnl_cfg) {
                  csum_on = tnl_cfg->csum;
              }
              netdev_close(outdev);
          }
      }
  
      info.dpif_class = dpif_class;
      info.tp_dst_port = dst_port;
      info.tunnel_csum_on = csum_on;
      err = netdev_flow_put(dev, &match,
                            CONST_CAST(struct nlattr *, put->actions),
                            put->actions_len,
                            CONST_CAST(ovs_u128 *, put->ufid),
                            &info, put->stats);
  
      if (!err) {
          if (put->flags & DPIF_FP_MODIFY) {
              struct dpif_op *opp;
              struct dpif_op op;
  
              op.type = DPIF_OP_FLOW_DEL;
              op.flow_del.key = put->key;
              op.flow_del.key_len = put->key_len;
              op.flow_del.ufid = put->ufid;
              op.flow_del.pmd_id = put->pmd_id;
              op.flow_del.stats = NULL;
              op.flow_del.terse = false;
  
              opp = &op;
              dpif_netlink_operate__(dpif, &opp, 1);
          }
  
          VLOG_DBG("added flow");
      } else if (err != EEXIST) {
          struct netdev *oor_netdev = NULL;
          enum vlog_level level;
          if (err == ENOSPC && netdev_is_offload_rebalance_policy_enabled()) {
              /*
               * We need to set OOR on the input netdev (i.e, 'dev') for the
               * flow. But if the flow has a tunnel attribute (i.e, decap action,
               * with a virtual device like a VxLAN interface as its in-port),
               * then lookup and set OOR on the underlying tunnel (real) netdev.
               */
              oor_netdev = flow_get_tunnel_netdev(&match.flow.tunnel);
              if (!oor_netdev) {
                  /* Not a 'tunnel' flow */
                  oor_netdev = dev;
              }
              netdev_set_hw_info(oor_netdev, HW_INFO_TYPE_OOR, true);
          }
          level = (err == ENOSPC || err == EOPNOTSUPP) ? VLL_DBG : VLL_ERR;
          VLOG_RL(&rl, level, "failed to offload flow: %s: %s",
                  ovs_strerror(err),
                  (oor_netdev ? oor_netdev->name : dev->name));
      }
  
  out:
      if (err && err != EEXIST && (put->flags & DPIF_FP_MODIFY)) {
          /* Modified rule can't be offloaded, try and delete from HW */
          int del_err = netdev_flow_del(dev, put->ufid, put->stats);
  
          if (!del_err) {
              /* Delete from hw success, so old flow was offloaded.
               * Change flags to create the flow in kernel */
              put->flags &= ~DPIF_FP_MODIFY;
              put->flags |= DPIF_FP_CREATE;
          } else if (del_err != ENOENT) {
              VLOG_ERR_RL(&rl, "failed to delete offloaded flow: %s",
                          ovs_strerror(del_err));
              /* stop proccesing the flow in kernel */
              err = 0;
          }
      }
  
      netdev_close(dev);
  
      return err;
  }
  
  static int
  try_send_to_netdev(struct dpif_netlink *dpif, struct dpif_op *op)
  {
      int err = EOPNOTSUPP;
  
      switch (op->type) {
      case DPIF_OP_FLOW_PUT: {
          struct dpif_flow_put *put = &op->flow_put;
  
          if (!put->ufid) {
              break;
          }
  
          log_flow_put_message(&dpif->dpif, &this_module, put, 0);
          err = parse_flow_put(dpif, put);
          break;
      }
      case DPIF_OP_FLOW_DEL: {
          struct dpif_flow_del *del = &op->flow_del;
  
          if (!del->ufid) {
              break;
          }
  
          log_flow_del_message(&dpif->dpif, &this_module, del, 0);
          err = netdev_ports_flow_del(dpif->dpif.dpif_class, del->ufid,
                                      del->stats);
          break;
      }
      case DPIF_OP_FLOW_GET: {
          struct dpif_flow_get *get = &op->flow_get;
  
          if (!op->flow_get.ufid) {
              break;
          }
  
          log_flow_get_message(&dpif->dpif, &this_module, get, 0);
          err = parse_flow_get(dpif, get);
          break;
      }
      case DPIF_OP_EXECUTE:
      default:
          break;
      }
  
      return err;
  }
  
  static void
  dpif_netlink_operate_chunks(struct dpif_netlink *dpif, struct dpif_op **ops,
                              size_t n_ops)
  {
      while (n_ops > 0) {
          size_t chunk = dpif_netlink_operate__(dpif, ops, n_ops);
  
          ops += chunk;
          n_ops -= chunk;
      }
  }
  
  static void
  dpif_netlink_operate(struct dpif *dpif_, struct dpif_op **ops, size_t n_ops,
                       enum dpif_offload_type offload_type)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct dpif_op *new_ops[OPERATE_MAX_OPS];
      int count = 0;
      int i = 0;
      int err = 0;
  
      if (offload_type == DPIF_OFFLOAD_ALWAYS && !netdev_is_flow_api_enabled()) {
          VLOG_DBG("Invalid offload_type: %d", offload_type);
          return;
      }
  
      if (offload_type != DPIF_OFFLOAD_NEVER && netdev_is_flow_api_enabled()) {
          while (n_ops > 0) {
              count = 0;
  
              while (n_ops > 0 && count < OPERATE_MAX_OPS) {
                  struct dpif_op *op = ops[i++];
  
                  err = try_send_to_netdev(dpif, op);
                  if (err && err != EEXIST) {
                      if (offload_type == DPIF_OFFLOAD_ALWAYS) {
                          /* We got an error while offloading an op. Since
                           * OFFLOAD_ALWAYS is specified, we stop further
                           * processing and return to the caller without
                           * invoking kernel datapath as fallback. But the
                           * interface requires us to process all n_ops; so
                           * return the same error in the remaining ops too.
                           */
                          op->error = err;
                          n_ops--;
                          while (n_ops > 0) {
                              op = ops[i++];
                              op->error = err;
                              n_ops--;
                          }
                          return;
                      }
                      new_ops[count++] = op;
                  } else {
                      op->error = err;
                  }
  
                  n_ops--;
              }
  
              dpif_netlink_operate_chunks(dpif, new_ops, count);
          }
      } else if (offload_type != DPIF_OFFLOAD_ALWAYS) {
          dpif_netlink_operate_chunks(dpif, ops, n_ops);
      }
  }
  
  #if _WIN32
  static void
  dpif_netlink_handler_uninit(struct dpif_handler *handler)
  {
      vport_delete_sock_pool(handler);
  }
  
  static int
  dpif_netlink_handler_init(struct dpif_handler *handler)
  {
      return vport_create_sock_pool(handler);
  }
  #else
  
  static int
  dpif_netlink_handler_init(struct dpif_handler *handler)
  {
      handler->epoll_fd = epoll_create(10);
      return handler->epoll_fd < 0 ? errno : 0;
  }
  
  static void
  dpif_netlink_handler_uninit(struct dpif_handler *handler)
  {
      close(handler->epoll_fd);
  }
  #endif
  
  /* Synchronizes 'channels' in 'dpif->handlers'  with the set of vports
   * currently in 'dpif' in the kernel, by adding a new set of channels for
   * any kernel vport that lacks one and deleting any channels that have no
   * backing kernel vports. */
  static int
  dpif_netlink_refresh_channels(struct dpif_netlink *dpif, uint32_t n_handlers)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      unsigned long int *keep_channels;
      struct dpif_netlink_vport vport;
      size_t keep_channels_nbits;
      struct nl_dump dump;
      uint64_t reply_stub[NL_DUMP_BUFSIZE / 8];
      struct ofpbuf buf;
      int retval = 0;
      size_t i;
  
      ovs_assert(!WINDOWS || n_handlers <= 1);
      ovs_assert(!WINDOWS || dpif->n_handlers <= 1);
  
      if (dpif->n_handlers != n_handlers) {
          destroy_all_channels(dpif);
          dpif->handlers = xzalloc(n_handlers * sizeof *dpif->handlers);
          for (i = 0; i < n_handlers; i++) {
              int error;
              struct dpif_handler *handler = &dpif->handlers[i];
  
              error = dpif_netlink_handler_init(handler);
              if (error) {
                  size_t j;
  
                  for (j = 0; j < i; j++) {
                      struct dpif_handler *tmp = &dpif->handlers[j];
                      dpif_netlink_handler_uninit(tmp);
                  }
                  free(dpif->handlers);
                  dpif->handlers = NULL;
  
                  return error;
              }
          }
          dpif->n_handlers = n_handlers;
      }
  
      for (i = 0; i < n_handlers; i++) {
          struct dpif_handler *handler = &dpif->handlers[i];
  
          handler->event_offset = handler->n_events = 0;
      }
  
      keep_channels_nbits = dpif->uc_array_size;
      keep_channels = bitmap_allocate(keep_channels_nbits);
  
      ofpbuf_use_stub(&buf, reply_stub, sizeof reply_stub);
      dpif_netlink_port_dump_start__(dpif, &dump);
      while (!dpif_netlink_port_dump_next__(dpif, &dump, &vport, &buf)) {
          uint32_t port_no = odp_to_u32(vport.port_no);
          uint32_t upcall_pid;
          int error;
  
          if (port_no >= dpif->uc_array_size
              || !vport_get_pid(dpif, port_no, &upcall_pid)) {
              struct nl_sock *sock;
              error = create_nl_sock(dpif, &sock);
  
              if (error) {
                  goto error;
              }
  
              error = vport_add_channel(dpif, vport.port_no, sock);
              if (error) {
                  VLOG_INFO("%s: could not add channels for port %s",
                            dpif_name(&dpif->dpif), vport.name);
                  nl_sock_destroy(sock);
                  retval = error;
                  goto error;
              }
              upcall_pid = nl_sock_pid(sock);
          }
  
          /* Configure the vport to deliver misses to 'sock'. */
          if (vport.upcall_pids[0] == 0
              || vport.n_upcall_pids != 1
              || upcall_pid != vport.upcall_pids[0]) {
              struct dpif_netlink_vport vport_request;
  
              dpif_netlink_vport_init(&vport_request);
              vport_request.cmd = OVS_VPORT_CMD_SET;
              vport_request.dp_ifindex = dpif->dp_ifindex;
              vport_request.port_no = vport.port_no;
              vport_request.n_upcall_pids = 1;
              vport_request.upcall_pids = &upcall_pid;
              error = dpif_netlink_vport_transact(&vport_request, NULL, NULL);
              if (error) {
                  VLOG_WARN_RL(&error_rl,
                               "%s: failed to set upcall pid on port: %s",
                               dpif_name(&dpif->dpif), ovs_strerror(error));
  
                  if (error != ENODEV && error != ENOENT) {
                      retval = error;
                  } else {
                      /* The vport isn't really there, even though the dump says
                       * it is.  Probably we just hit a race after a port
                       * disappeared. */
                  }
                  goto error;
              }
          }
  
          if (port_no < keep_channels_nbits) {
              bitmap_set1(keep_channels, port_no);
          }
          continue;
  
      error:
          vport_del_channels(dpif, vport.port_no);
      }
      nl_dump_done(&dump);
      ofpbuf_uninit(&buf);
  
      /* Discard any saved channels that we didn't reuse. */
      for (i = 0; i < keep_channels_nbits; i++) {
          if (!bitmap_is_set(keep_channels, i)) {
              vport_del_channels(dpif, u32_to_odp(i));
          }
      }
      free(keep_channels);
  
      return retval;
  }
  
  static int
  dpif_netlink_recv_set__(struct dpif_netlink *dpif, bool enable)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      if ((dpif->handlers != NULL) == enable) {
          return 0;
      } else if (!enable) {
          destroy_all_channels(dpif);
          return 0;
      } else {
          return dpif_netlink_refresh_channels(dpif, 1);
      }
  }
  
  static int
  dpif_netlink_recv_set(struct dpif *dpif_, bool enable)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      int error;
  
      fat_rwlock_wrlock(&dpif->upcall_lock);
      error = dpif_netlink_recv_set__(dpif, enable);
      fat_rwlock_unlock(&dpif->upcall_lock);
  
      return error;
  }
  
  static int
  dpif_netlink_handlers_set(struct dpif *dpif_, uint32_t n_handlers)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      int error = 0;
  
  #ifdef _WIN32
      /* Multiple upcall handlers will be supported once kernel datapath supports
       * it. */
      if (n_handlers > 1) {
          return error;
      }
  #endif
  
      fat_rwlock_wrlock(&dpif->upcall_lock);
      if (dpif->handlers) {
          error = dpif_netlink_refresh_channels(dpif, n_handlers);
      }
      fat_rwlock_unlock(&dpif->upcall_lock);
  
      return error;
  }
  
  static int
  dpif_netlink_queue_to_priority(const struct dpif *dpif OVS_UNUSED,
                               uint32_t queue_id, uint32_t *priority)
  {
      if (queue_id < 0xf000) {
          *priority = TC_H_MAKE(1 << 16, queue_id + 1);
          return 0;
      } else {
          return EINVAL;
      }
  }
  
  static int
  parse_odp_packet(const struct dpif_netlink *dpif, struct ofpbuf *buf,
                   struct dpif_upcall *upcall, int *dp_ifindex)
  {
      static const struct nl_policy ovs_packet_policy[] = {
          /* Always present. */
          [OVS_PACKET_ATTR_PACKET] = { .type = NL_A_UNSPEC,
                                       .min_len = ETH_HEADER_LEN },
          [OVS_PACKET_ATTR_KEY] = { .type = NL_A_NESTED },
  
          /* OVS_PACKET_CMD_ACTION only. */
          [OVS_PACKET_ATTR_USERDATA] = { .type = NL_A_UNSPEC, .optional = true },
          [OVS_PACKET_ATTR_EGRESS_TUN_KEY] = { .type = NL_A_NESTED, .optional = true },
          [OVS_PACKET_ATTR_ACTIONS] = { .type = NL_A_NESTED, .optional = true },
          [OVS_PACKET_ATTR_MRU] = { .type = NL_A_U16, .optional = true }
      };
  
      struct ofpbuf b = ofpbuf_const_initializer(buf->data, buf->size);
      struct nlmsghdr *nlmsg = ofpbuf_try_pull(&b, sizeof *nlmsg);
      struct genlmsghdr *genl = ofpbuf_try_pull(&b, sizeof *genl);
      struct ovs_header *ovs_header = ofpbuf_try_pull(&b, sizeof *ovs_header);
  
      struct nlattr *a[ARRAY_SIZE(ovs_packet_policy)];
      if (!nlmsg || !genl || !ovs_header
          || nlmsg->nlmsg_type != ovs_packet_family
          || !nl_policy_parse(&b, 0, ovs_packet_policy, a,
                              ARRAY_SIZE(ovs_packet_policy))) {
          return EINVAL;
      }
  
      int type = (genl->cmd == OVS_PACKET_CMD_MISS ? DPIF_UC_MISS
                  : genl->cmd == OVS_PACKET_CMD_ACTION ? DPIF_UC_ACTION
                  : -1);
      if (type < 0) {
          return EINVAL;
      }
  
      /* (Re)set ALL fields of '*upcall' on successful return. */
      upcall->type = type;
      upcall->key = CONST_CAST(struct nlattr *,
                               nl_attr_get(a[OVS_PACKET_ATTR_KEY]));
      upcall->key_len = nl_attr_get_size(a[OVS_PACKET_ATTR_KEY]);
      dpif_flow_hash(&dpif->dpif, upcall->key, upcall->key_len, &upcall->ufid);
      upcall->userdata = a[OVS_PACKET_ATTR_USERDATA];
      upcall->out_tun_key = a[OVS_PACKET_ATTR_EGRESS_TUN_KEY];
      upcall->actions = a[OVS_PACKET_ATTR_ACTIONS];
      upcall->mru = a[OVS_PACKET_ATTR_MRU];
  
      /* Allow overwriting the netlink attribute header without reallocating. */
      dp_packet_use_stub(&upcall->packet,
                      CONST_CAST(struct nlattr *,
                                 nl_attr_get(a[OVS_PACKET_ATTR_PACKET])) - 1,
                      nl_attr_get_size(a[OVS_PACKET_ATTR_PACKET]) +
                      sizeof(struct nlattr));
      dp_packet_set_data(&upcall->packet,
                      (char *)dp_packet_data(&upcall->packet) + sizeof(struct nlattr));
      dp_packet_set_size(&upcall->packet, nl_attr_get_size(a[OVS_PACKET_ATTR_PACKET]));
  
      if (nl_attr_find__(upcall->key, upcall->key_len, OVS_KEY_ATTR_ETHERNET)) {
          /* Ethernet frame */
          upcall->packet.packet_type = htonl(PT_ETH);
      } else {
          /* Non-Ethernet packet. Get the Ethertype from the NL attributes */
          ovs_be16 ethertype = 0;
          const struct nlattr *et_nla = nl_attr_find__(upcall->key,
                                                       upcall->key_len,
                                                       OVS_KEY_ATTR_ETHERTYPE);
          if (et_nla) {
              ethertype = nl_attr_get_be16(et_nla);
          }
          upcall->packet.packet_type = PACKET_TYPE_BE(OFPHTN_ETHERTYPE,
                                                      ntohs(ethertype));
          dp_packet_set_l3(&upcall->packet, dp_packet_data(&upcall->packet));
      }
  
      *dp_ifindex = ovs_header->dp_ifindex;
  
      return 0;
  }
  
  #ifdef _WIN32
  #define PACKET_RECV_BATCH_SIZE 50
  static int
  dpif_netlink_recv_windows(struct dpif_netlink *dpif, uint32_t handler_id,
                            struct dpif_upcall *upcall, struct ofpbuf *buf)
      OVS_REQ_RDLOCK(dpif->upcall_lock)
  {
      struct dpif_handler *handler;
      int read_tries = 0;
      struct dpif_windows_vport_sock *sock_pool;
      uint32_t i;
  
      if (!dpif->handlers) {
          return EAGAIN;
      }
  
      /* Only one handler is supported currently. */
      if (handler_id >= 1) {
          return EAGAIN;
      }
  
      if (handler_id >= dpif->n_handlers) {
          return EAGAIN;
      }
  
      handler = &dpif->handlers[handler_id];
      sock_pool = handler->vport_sock_pool;
  
      for (i = 0; i < VPORT_SOCK_POOL_SIZE; i++) {
          for (;;) {
              int dp_ifindex;
              int error;
  
              if (++read_tries > PACKET_RECV_BATCH_SIZE) {
                  return EAGAIN;
              }
  
              error = nl_sock_recv(sock_pool[i].nl_sock, buf, NULL, false);
              if (error == ENOBUFS) {
                  /* ENOBUFS typically means that we've received so many
                   * packets that the buffer overflowed.  Try again
                   * immediately because there's almost certainly a packet
                   * waiting for us. */
                  /* XXX: report_loss(dpif, ch, idx, handler_id); */
                  continue;
              }
  
              /* XXX: ch->last_poll = time_msec(); */
              if (error) {
                  if (error == EAGAIN) {
                      break;
                  }
                  return error;
              }
  
              error = parse_odp_packet(dpif, buf, upcall, &dp_ifindex);
              if (!error && dp_ifindex == dpif->dp_ifindex) {
                  return 0;
              } else if (error) {
                  return error;
              }
          }
      }
  
      return EAGAIN;
  }
  #else
  static int
  dpif_netlink_recv__(struct dpif_netlink *dpif, uint32_t handler_id,
                      struct dpif_upcall *upcall, struct ofpbuf *buf)
      OVS_REQ_RDLOCK(dpif->upcall_lock)
  {
      struct dpif_handler *handler;
      int read_tries = 0;
  
      if (!dpif->handlers || handler_id >= dpif->n_handlers) {
          return EAGAIN;
      }
  
      handler = &dpif->handlers[handler_id];
      if (handler->event_offset >= handler->n_events) {
          int retval;
  
          handler->event_offset = handler->n_events = 0;
  
          do {
              retval = epoll_wait(handler->epoll_fd, handler->epoll_events,
                                  dpif->uc_array_size, 0);
          } while (retval < 0 && errno == EINTR);
  
          if (retval < 0) {
              static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
              VLOG_WARN_RL(&rl, "epoll_wait failed (%s)", ovs_strerror(errno));
          } else if (retval > 0) {
              handler->n_events = retval;
          }
      }
  
      while (handler->event_offset < handler->n_events) {
          int idx = handler->epoll_events[handler->event_offset].data.u32;
          struct dpif_channel *ch = &dpif->channels[idx];
  
          handler->event_offset++;
  
          for (;;) {
              int dp_ifindex;
              int error;
  
              if (++read_tries > 50) {
                  return EAGAIN;
              }
  
              error = nl_sock_recv(ch->sock, buf, NULL, false);
              if (error == ENOBUFS) {
                  /* ENOBUFS typically means that we've received so many
                   * packets that the buffer overflowed.  Try again
                   * immediately because there's almost certainly a packet
                   * waiting for us. */
                  report_loss(dpif, ch, idx, handler_id);
                  continue;
              }
  
              ch->last_poll = time_msec();
              if (error) {
                  if (error == EAGAIN) {
                      break;
                  }
                  return error;
              }
  
              error = parse_odp_packet(dpif, buf, upcall, &dp_ifindex);
              if (!error && dp_ifindex == dpif->dp_ifindex) {
                  return 0;
              } else if (error) {
                  return error;
              }
          }
      }
  
      return EAGAIN;
  }
  #endif
  
  static int
  dpif_netlink_recv(struct dpif *dpif_, uint32_t handler_id,
                    struct dpif_upcall *upcall, struct ofpbuf *buf)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      int error;
  
      fat_rwlock_rdlock(&dpif->upcall_lock);
  #ifdef _WIN32
      error = dpif_netlink_recv_windows(dpif, handler_id, upcall, buf);
  #else
      error = dpif_netlink_recv__(dpif, handler_id, upcall, buf);
  #endif
      fat_rwlock_unlock(&dpif->upcall_lock);
  
      return error;
  }
  
  static void
  dpif_netlink_recv_wait__(struct dpif_netlink *dpif, uint32_t handler_id)
      OVS_REQ_RDLOCK(dpif->upcall_lock)
  {
  #ifdef _WIN32
      uint32_t i;
      struct dpif_windows_vport_sock *sock_pool =
          dpif->handlers[handler_id].vport_sock_pool;
  
      /* Only one handler is supported currently. */
      if (handler_id >= 1) {
          return;
      }
  
      for (i = 0; i < VPORT_SOCK_POOL_SIZE; i++) {
          nl_sock_wait(sock_pool[i].nl_sock, POLLIN);
      }
  #else
      if (dpif->handlers && handler_id < dpif->n_handlers) {
          struct dpif_handler *handler = &dpif->handlers[handler_id];
  
          poll_fd_wait(handler->epoll_fd, POLLIN);
      }
  #endif
  }
  
  static void
  dpif_netlink_recv_wait(struct dpif *dpif_, uint32_t handler_id)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
  
      fat_rwlock_rdlock(&dpif->upcall_lock);
      dpif_netlink_recv_wait__(dpif, handler_id);
      fat_rwlock_unlock(&dpif->upcall_lock);
  }
  
  static void
  dpif_netlink_recv_purge__(struct dpif_netlink *dpif)
      OVS_REQ_WRLOCK(dpif->upcall_lock)
  {
      if (dpif->handlers) {
          size_t i;
  
          if (!dpif->channels[0].sock) {
              return;
          }
          for (i = 0; i < dpif->uc_array_size; i++ ) {
  
              nl_sock_drain(dpif->channels[i].sock);
          }
      }
  }
  
  static void
  dpif_netlink_recv_purge(struct dpif *dpif_)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
  
      fat_rwlock_wrlock(&dpif->upcall_lock);
      dpif_netlink_recv_purge__(dpif);
      fat_rwlock_unlock(&dpif->upcall_lock);
  }
  
  static char *
  dpif_netlink_get_datapath_version(void)
  {
      char *version_str = NULL;
  
  #ifdef __linux__
  
  #define MAX_VERSION_STR_SIZE 80
  #define LINUX_DATAPATH_VERSION_FILE  "/sys/module/openvswitch/version"
      FILE *f;
  
      f = fopen(LINUX_DATAPATH_VERSION_FILE, "r");
      if (f) {
          char *newline;
          char version[MAX_VERSION_STR_SIZE];
  
          if (fgets(version, MAX_VERSION_STR_SIZE, f)) {
              newline = strchr(version, '\n');
              if (newline) {
                  *newline = '\0';
              }
              version_str = xstrdup(version);
          }
          fclose(f);
      }
  #endif
  
      return version_str;
  }
  
  struct dpif_netlink_ct_dump_state {
      struct ct_dpif_dump_state up;
      struct nl_ct_dump_state *nl_ct_dump;
  };
  
  static int
  dpif_netlink_ct_dump_start(struct dpif *dpif OVS_UNUSED,
                             struct ct_dpif_dump_state **dump_,
                             const uint16_t *zone, int *ptot_bkts)
  {
      struct dpif_netlink_ct_dump_state *dump;
      int err;
  
      dump = xzalloc(sizeof *dump);
      err = nl_ct_dump_start(&dump->nl_ct_dump, zone, ptot_bkts);
      if (err) {
          free(dump);
          return err;
      }
  
      *dump_ = &dump->up;
  
      return 0;
  }
  
  static int
  dpif_netlink_ct_dump_next(struct dpif *dpif OVS_UNUSED,
                            struct ct_dpif_dump_state *dump_,
                            struct ct_dpif_entry *entry)
  {
      struct dpif_netlink_ct_dump_state *dump;
  
      INIT_CONTAINER(dump, dump_, up);
  
      return nl_ct_dump_next(dump->nl_ct_dump, entry);
  }
  
  static int
  dpif_netlink_ct_dump_done(struct dpif *dpif OVS_UNUSED,
                            struct ct_dpif_dump_state *dump_)
  {
      struct dpif_netlink_ct_dump_state *dump;
  
      INIT_CONTAINER(dump, dump_, up);
  
      int err = nl_ct_dump_done(dump->nl_ct_dump);
      free(dump);
      return err;
  }
  
  static int
  dpif_netlink_ct_flush(struct dpif *dpif OVS_UNUSED, const uint16_t *zone,
                        const struct ct_dpif_tuple *tuple)
  {
      if (tuple) {
          return nl_ct_flush_tuple(tuple, zone ? *zone : 0);
      } else if (zone) {
          return nl_ct_flush_zone(*zone);
      } else {
          return nl_ct_flush();
      }
  }
  
  static int
  dpif_netlink_ct_set_limits(struct dpif *dpif OVS_UNUSED,
                             const uint32_t *default_limits,
                             const struct ovs_list *zone_limits)
  {
      struct ovs_zone_limit req_zone_limit;
  
      if (ovs_ct_limit_family < 0) {
          return EOPNOTSUPP;
      }
  
      struct ofpbuf *request = ofpbuf_new(NL_DUMP_BUFSIZE);
      nl_msg_put_genlmsghdr(request, 0, ovs_ct_limit_family,
                            NLM_F_REQUEST | NLM_F_ECHO, OVS_CT_LIMIT_CMD_SET,
                            OVS_CT_LIMIT_VERSION);
  
      struct ovs_header *ovs_header;
      ovs_header = ofpbuf_put_uninit(request, sizeof *ovs_header);
      ovs_header->dp_ifindex = 0;
  
      size_t opt_offset;
      opt_offset = nl_msg_start_nested(request, OVS_CT_LIMIT_ATTR_ZONE_LIMIT);
      if (default_limits) {
          req_zone_limit.zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE;
          req_zone_limit.limit = *default_limits;
          nl_msg_put(request, &req_zone_limit, sizeof req_zone_limit);
      }
  
      if (!ovs_list_is_empty(zone_limits)) {
          struct ct_dpif_zone_limit *zone_limit;
  
          LIST_FOR_EACH (zone_limit, node, zone_limits) {
              req_zone_limit.zone_id = zone_limit->zone;
              req_zone_limit.limit = zone_limit->limit;
              nl_msg_put(request, &req_zone_limit, sizeof req_zone_limit);
          }
      }
      nl_msg_end_nested(request, opt_offset);
  
      int err = nl_transact(NETLINK_GENERIC, request, NULL);
      ofpbuf_delete(request);
      return err;
  }
  
  static int
  dpif_netlink_zone_limits_from_ofpbuf(const struct ofpbuf *buf,
                                       uint32_t *default_limit,
                                       struct ovs_list *zone_limits)
  {
      static const struct nl_policy ovs_ct_limit_policy[] = {
          [OVS_CT_LIMIT_ATTR_ZONE_LIMIT] = { .type = NL_A_NESTED,
                                             .optional = true },
      };
  
      struct ofpbuf b = ofpbuf_const_initializer(buf->data, buf->size);
      struct nlmsghdr *nlmsg = ofpbuf_try_pull(&b, sizeof *nlmsg);
      struct genlmsghdr *genl = ofpbuf_try_pull(&b, sizeof *genl);
      struct ovs_header *ovs_header = ofpbuf_try_pull(&b, sizeof *ovs_header);
  
      struct nlattr *attr[ARRAY_SIZE(ovs_ct_limit_policy)];
  
      if (!nlmsg || !genl || !ovs_header
          || nlmsg->nlmsg_type != ovs_ct_limit_family
          || !nl_policy_parse(&b, 0, ovs_ct_limit_policy, attr,
                              ARRAY_SIZE(ovs_ct_limit_policy))) {
          return EINVAL;
      }
  
  
      if (!attr[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]) {
          return EINVAL;
      }
  
      int rem = NLA_ALIGN(
                  nl_attr_get_size(attr[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]));
      const struct ovs_zone_limit *zone_limit =
                  nl_attr_get(attr[OVS_CT_LIMIT_ATTR_ZONE_LIMIT]);
  
      while (rem >= sizeof *zone_limit) {
          if (zone_limit->zone_id == OVS_ZONE_LIMIT_DEFAULT_ZONE) {
              *default_limit = zone_limit->limit;
          } else if (zone_limit->zone_id < OVS_ZONE_LIMIT_DEFAULT_ZONE ||
                     zone_limit->zone_id > UINT16_MAX) {
          } else {
              ct_dpif_push_zone_limit(zone_limits, zone_limit->zone_id,
                                      zone_limit->limit, zone_limit->count);
          }
          rem -= NLA_ALIGN(sizeof *zone_limit);
          zone_limit = ALIGNED_CAST(struct ovs_zone_limit *,
              (unsigned char *) zone_limit  + NLA_ALIGN(sizeof *zone_limit));
      }
      return 0;
  }
  
  static int
  dpif_netlink_ct_get_limits(struct dpif *dpif OVS_UNUSED,
                             uint32_t *default_limit,
                             const struct ovs_list *zone_limits_request,
                             struct ovs_list *zone_limits_reply)
  {
      if (ovs_ct_limit_family < 0) {
          return EOPNOTSUPP;
      }
  
      struct ofpbuf *request = ofpbuf_new(NL_DUMP_BUFSIZE);
      nl_msg_put_genlmsghdr(request, 0, ovs_ct_limit_family,
              NLM_F_REQUEST | NLM_F_ECHO, OVS_CT_LIMIT_CMD_GET,
              OVS_CT_LIMIT_VERSION);
  
      struct ovs_header *ovs_header;
      ovs_header = ofpbuf_put_uninit(request, sizeof *ovs_header);
      ovs_header->dp_ifindex = 0;
  
      if (!ovs_list_is_empty(zone_limits_request)) {
          size_t opt_offset = nl_msg_start_nested(request,
                                                  OVS_CT_LIMIT_ATTR_ZONE_LIMIT);
  
          struct ovs_zone_limit req_zone_limit;
          req_zone_limit.zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE;
          nl_msg_put(request, &req_zone_limit, sizeof req_zone_limit);
  
          struct ct_dpif_zone_limit *zone_limit;
          LIST_FOR_EACH (zone_limit, node, zone_limits_request) {
              req_zone_limit.zone_id = zone_limit->zone;
              nl_msg_put(request, &req_zone_limit, sizeof req_zone_limit);
          }
  
          nl_msg_end_nested(request, opt_offset);
      }
  
      struct ofpbuf *reply;
      int err = nl_transact(NETLINK_GENERIC, request, &reply);
      if (err) {
          goto out;
      }
  
      err = dpif_netlink_zone_limits_from_ofpbuf(reply, default_limit,
                                                 zone_limits_reply);
  
  out:
      ofpbuf_delete(request);
      ofpbuf_delete(reply);
      return err;
  }
  
  static int
  dpif_netlink_ct_del_limits(struct dpif *dpif OVS_UNUSED,
                             const struct ovs_list *zone_limits)
  {
      if (ovs_ct_limit_family < 0) {
          return EOPNOTSUPP;
      }
  
      struct ofpbuf *request = ofpbuf_new(NL_DUMP_BUFSIZE);
      nl_msg_put_genlmsghdr(request, 0, ovs_ct_limit_family,
              NLM_F_REQUEST | NLM_F_ECHO, OVS_CT_LIMIT_CMD_DEL,
              OVS_CT_LIMIT_VERSION);
  
      struct ovs_header *ovs_header;
      ovs_header = ofpbuf_put_uninit(request, sizeof *ovs_header);
      ovs_header->dp_ifindex = 0;
  
      if (!ovs_list_is_empty(zone_limits)) {
          size_t opt_offset =
              nl_msg_start_nested(request, OVS_CT_LIMIT_ATTR_ZONE_LIMIT);
  
          struct ct_dpif_zone_limit *zone_limit;
          LIST_FOR_EACH (zone_limit, node, zone_limits) {
              struct ovs_zone_limit req_zone_limit;
              req_zone_limit.zone_id = zone_limit->zone;
              nl_msg_put(request, &req_zone_limit, sizeof req_zone_limit);
          }
          nl_msg_end_nested(request, opt_offset);
      }
  
      int err = nl_transact(NETLINK_GENERIC, request, NULL);
  
      ofpbuf_delete(request);
      return err;
  }
  
  #define NL_TP_NAME_PREFIX "ovs_tp_"
  
  struct dpif_netlink_timeout_policy_protocol {
      uint16_t    l3num;
      uint8_t     l4num;
  };
  
  enum OVS_PACKED_ENUM dpif_netlink_support_timeout_policy_protocol {
      DPIF_NL_TP_AF_INET_TCP,
      DPIF_NL_TP_AF_INET_UDP,
      DPIF_NL_TP_AF_INET_ICMP,
      DPIF_NL_TP_AF_INET6_TCP,
      DPIF_NL_TP_AF_INET6_UDP,
      DPIF_NL_TP_AF_INET6_ICMPV6,
      DPIF_NL_TP_MAX
  };
  
  #define DPIF_NL_ALL_TP ((1UL << DPIF_NL_TP_MAX) - 1)
  
  
  static struct dpif_netlink_timeout_policy_protocol tp_protos[] = {
      [DPIF_NL_TP_AF_INET_TCP] = { .l3num = AF_INET, .l4num = IPPROTO_TCP },
      [DPIF_NL_TP_AF_INET_UDP] = { .l3num = AF_INET, .l4num = IPPROTO_UDP },
      [DPIF_NL_TP_AF_INET_ICMP] = { .l3num = AF_INET, .l4num = IPPROTO_ICMP },
      [DPIF_NL_TP_AF_INET6_TCP] = { .l3num = AF_INET6, .l4num = IPPROTO_TCP },
      [DPIF_NL_TP_AF_INET6_UDP] = { .l3num = AF_INET6, .l4num = IPPROTO_UDP },
      [DPIF_NL_TP_AF_INET6_ICMPV6] = { .l3num = AF_INET6,
                                       .l4num = IPPROTO_ICMPV6 },
  };
  
  static void
  dpif_netlink_format_tp_name(uint32_t id, uint16_t l3num, uint8_t l4num,
                              char **tp_name)
  {
      struct ds ds = DS_EMPTY_INITIALIZER;
      ds_put_format(&ds, "%s%"PRIu32"_", NL_TP_NAME_PREFIX, id);
      ct_dpif_format_ipproto(&ds, l4num);
  
      if (l3num == AF_INET) {
          ds_put_cstr(&ds, "4");
      } else if (l3num == AF_INET6 && l4num != IPPROTO_ICMPV6) {
          ds_put_cstr(&ds, "6");
      }
  
      ovs_assert(ds.length < CTNL_TIMEOUT_NAME_MAX);
  
      *tp_name = ds_steal_cstr(&ds);
  }
  
  static int
  dpif_netlink_ct_get_timeout_policy_name(struct dpif *dpif OVS_UNUSED,
                                          uint32_t tp_id, uint16_t dl_type,
                                          uint8_t nw_proto, char **tp_name,
                                          bool *is_generic)
  {
      dpif_netlink_format_tp_name(tp_id,
                                  dl_type == ETH_TYPE_IP ? AF_INET : AF_INET6,
                                  nw_proto, tp_name);
      *is_generic = false;
      return 0;
  }
  
  #define CT_DPIF_NL_TP_TCP_MAPPINGS                              \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, SYN_SENT, SYN_SENT)         \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, SYN_RECV, SYN_RECV)         \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, ESTABLISHED, ESTABLISHED)   \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, FIN_WAIT, FIN_WAIT)         \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, CLOSE_WAIT, CLOSE_WAIT)     \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, LAST_ACK, LAST_ACK)         \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, TIME_WAIT, TIME_WAIT)       \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, CLOSE, CLOSE)               \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, SYN_SENT2, SYN_SENT2)       \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, RETRANSMIT, RETRANS)        \
      CT_DPIF_NL_TP_MAPPING(TCP, TCP, UNACK, UNACK)
  
  #define CT_DPIF_NL_TP_UDP_MAPPINGS                              \
      CT_DPIF_NL_TP_MAPPING(UDP, UDP, SINGLE, UNREPLIED)          \
      CT_DPIF_NL_TP_MAPPING(UDP, UDP, MULTIPLE, REPLIED)
  
  #define CT_DPIF_NL_TP_ICMP_MAPPINGS                             \
      CT_DPIF_NL_TP_MAPPING(ICMP, ICMP, FIRST, TIMEOUT)
  
  #define CT_DPIF_NL_TP_ICMPV6_MAPPINGS                           \
      CT_DPIF_NL_TP_MAPPING(ICMP, ICMPV6, FIRST, TIMEOUT)
  
  
  #define CT_DPIF_NL_TP_MAPPING(PROTO1, PROTO2, ATTR1, ATTR2)     \
  if (tp->present & (1 << CT_DPIF_TP_ATTR_##PROTO1##_##ATTR1)) {  \
      nl_tp->present |= 1 << CTA_TIMEOUT_##PROTO2##_##ATTR2;      \
      nl_tp->attrs[CTA_TIMEOUT_##PROTO2##_##ATTR2] =              \
          tp->attrs[CT_DPIF_TP_ATTR_##PROTO1##_##ATTR1];          \
  }
  
  static void
  dpif_netlink_get_nl_tp_tcp_attrs(const struct ct_dpif_timeout_policy *tp,
                                   struct nl_ct_timeout_policy *nl_tp)
  {
      CT_DPIF_NL_TP_TCP_MAPPINGS
  }
  
  static void
  dpif_netlink_get_nl_tp_udp_attrs(const struct ct_dpif_timeout_policy *tp,
                                   struct nl_ct_timeout_policy *nl_tp)
  {
      CT_DPIF_NL_TP_UDP_MAPPINGS
  }
  
  static void
  dpif_netlink_get_nl_tp_icmp_attrs(const struct ct_dpif_timeout_policy *tp,
                                    struct nl_ct_timeout_policy *nl_tp)
  {
      CT_DPIF_NL_TP_ICMP_MAPPINGS
  }
  
  static void
  dpif_netlink_get_nl_tp_icmpv6_attrs(const struct ct_dpif_timeout_policy *tp,
                                      struct nl_ct_timeout_policy *nl_tp)
  {
      CT_DPIF_NL_TP_ICMPV6_MAPPINGS
  }
  
  #undef CT_DPIF_NL_TP_MAPPING
  
  static void
  dpif_netlink_get_nl_tp_attrs(const struct ct_dpif_timeout_policy *tp,
                               uint8_t l4num, struct nl_ct_timeout_policy *nl_tp)
  {
      nl_tp->present = 0;
  
      if (l4num == IPPROTO_TCP) {
          dpif_netlink_get_nl_tp_tcp_attrs(tp, nl_tp);
      } else if (l4num == IPPROTO_UDP) {
          dpif_netlink_get_nl_tp_udp_attrs(tp, nl_tp);
      } else if (l4num == IPPROTO_ICMP) {
          dpif_netlink_get_nl_tp_icmp_attrs(tp, nl_tp);
      } else if (l4num == IPPROTO_ICMPV6) {
          dpif_netlink_get_nl_tp_icmpv6_attrs(tp, nl_tp);
      }
  }
  
  #define CT_DPIF_NL_TP_MAPPING(PROTO1, PROTO2, ATTR1, ATTR2)                 \
  if (nl_tp->present & (1 << CTA_TIMEOUT_##PROTO2##_##ATTR2)) {               \
      if (tp->present & (1 << CT_DPIF_TP_ATTR_##PROTO1##_##ATTR1)) {          \
          if (tp->attrs[CT_DPIF_TP_ATTR_##PROTO1##_##ATTR1] !=                \
              nl_tp->attrs[CTA_TIMEOUT_##PROTO2##_##ATTR2]) {                 \
              VLOG_WARN_RL(&error_rl, "Inconsistent timeout policy %s "       \
                           "attribute %s=%"PRIu32" while %s=%"PRIu32,         \
                           nl_tp->name, "CTA_TIMEOUT_"#PROTO2"_"#ATTR2,       \
                           nl_tp->attrs[CTA_TIMEOUT_##PROTO2##_##ATTR2],      \
                           "CT_DPIF_TP_ATTR_"#PROTO1"_"#ATTR1,                \
                           tp->attrs[CT_DPIF_TP_ATTR_##PROTO1##_##ATTR1]);    \
          }                                                                   \
      } else {                                                                \
          tp->present |= 1 << CT_DPIF_TP_ATTR_##PROTO1##_##ATTR1;             \
          tp->attrs[CT_DPIF_TP_ATTR_##PROTO1##_##ATTR1] =                     \
              nl_tp->attrs[CTA_TIMEOUT_##PROTO2##_##ATTR2];                   \
      }                                                                       \
  }
  
  static void
  dpif_netlink_set_ct_dpif_tp_tcp_attrs(const struct nl_ct_timeout_policy *nl_tp,
                                        struct ct_dpif_timeout_policy *tp)
  {
      CT_DPIF_NL_TP_TCP_MAPPINGS
  }
  
  static void
  dpif_netlink_set_ct_dpif_tp_udp_attrs(const struct nl_ct_timeout_policy *nl_tp,
                                        struct ct_dpif_timeout_policy *tp)
  {
      CT_DPIF_NL_TP_UDP_MAPPINGS
  }
  
  static void
  dpif_netlink_set_ct_dpif_tp_icmp_attrs(
      const struct nl_ct_timeout_policy *nl_tp,
      struct ct_dpif_timeout_policy *tp)
  {
      CT_DPIF_NL_TP_ICMP_MAPPINGS
  }
  
  static void
  dpif_netlink_set_ct_dpif_tp_icmpv6_attrs(
      const struct nl_ct_timeout_policy *nl_tp,
      struct ct_dpif_timeout_policy *tp)
  {
      CT_DPIF_NL_TP_ICMPV6_MAPPINGS
  }
  
  #undef CT_DPIF_NL_TP_MAPPING
  
  static void
  dpif_netlink_set_ct_dpif_tp_attrs(const struct nl_ct_timeout_policy *nl_tp,
                                    struct ct_dpif_timeout_policy *tp)
  {
      if (nl_tp->l4num == IPPROTO_TCP) {
          dpif_netlink_set_ct_dpif_tp_tcp_attrs(nl_tp, tp);
      } else if (nl_tp->l4num == IPPROTO_UDP) {
          dpif_netlink_set_ct_dpif_tp_udp_attrs(nl_tp, tp);
      } else if (nl_tp->l4num == IPPROTO_ICMP) {
          dpif_netlink_set_ct_dpif_tp_icmp_attrs(nl_tp, tp);
      } else if (nl_tp->l4num == IPPROTO_ICMPV6) {
          dpif_netlink_set_ct_dpif_tp_icmpv6_attrs(nl_tp, tp);
      }
  }
  
  #ifdef _WIN32
  static int
  dpif_netlink_ct_set_timeout_policy(struct dpif *dpif OVS_UNUSED,
                                     const struct ct_dpif_timeout_policy *tp)
  {
      return EOPNOTSUPP;
  }
  
  static int
  dpif_netlink_ct_get_timeout_policy(struct dpif *dpif OVS_UNUSED,
                                     uint32_t tp_id,
                                     struct ct_dpif_timeout_policy *tp)
  {
      return EOPNOTSUPP;
  }
  
  static int
  dpif_netlink_ct_del_timeout_policy(struct dpif *dpif OVS_UNUSED,
                                     uint32_t tp_id)
  {
      return EOPNOTSUPP;
  }
  
  static int
  dpif_netlink_ct_timeout_policy_dump_start(struct dpif *dpif OVS_UNUSED,
                                            void **statep)
  {
      return EOPNOTSUPP;
  }
  
  static int
  dpif_netlink_ct_timeout_policy_dump_next(struct dpif *dpif OVS_UNUSED,
                                           void *state,
                                           struct ct_dpif_timeout_policy **tp)
  {
      return EOPNOTSUPP;
  }
  
  static int
  dpif_netlink_ct_timeout_policy_dump_done(struct dpif *dpif OVS_UNUSED,
                                           void *state)
  {
      return EOPNOTSUPP;
  }
  #else
  static int
  dpif_netlink_ct_set_timeout_policy(struct dpif *dpif OVS_UNUSED,
                                     const struct ct_dpif_timeout_policy *tp)
  {
      int err = 0;
  
      for (int i = 0; i < ARRAY_SIZE(tp_protos); ++i) {
          struct nl_ct_timeout_policy nl_tp;
          char *nl_tp_name;
  
          dpif_netlink_format_tp_name(tp->id, tp_protos[i].l3num,
                                      tp_protos[i].l4num, &nl_tp_name);
          ovs_strlcpy(nl_tp.name, nl_tp_name, sizeof nl_tp.name);
          free(nl_tp_name);
  
          nl_tp.l3num = tp_protos[i].l3num;
          nl_tp.l4num = tp_protos[i].l4num;
          dpif_netlink_get_nl_tp_attrs(tp, tp_protos[i].l4num, &nl_tp);
          err = nl_ct_set_timeout_policy(&nl_tp);
          if (err) {
              VLOG_WARN_RL(&error_rl, "failed to add timeout policy %s (%s)",
                           nl_tp.name, ovs_strerror(err));
              goto out;
          }
      }
  
  out:
      return err;
  }
  
  static int
  dpif_netlink_ct_get_timeout_policy(struct dpif *dpif OVS_UNUSED,
                                     uint32_t tp_id,
                                     struct ct_dpif_timeout_policy *tp)
  {
      int err = 0;
  
      tp->id = tp_id;
      tp->present = 0;
      for (int i = 0; i < ARRAY_SIZE(tp_protos); ++i) {
          struct nl_ct_timeout_policy nl_tp;
          char *nl_tp_name;
  
          dpif_netlink_format_tp_name(tp_id, tp_protos[i].l3num,
                                      tp_protos[i].l4num, &nl_tp_name);
          err = nl_ct_get_timeout_policy(nl_tp_name, &nl_tp);
  
          if (err) {
              VLOG_WARN_RL(&error_rl, "failed to get timeout policy %s (%s)",
                           nl_tp_name, ovs_strerror(err));
              free(nl_tp_name);
              goto out;
          }
          free(nl_tp_name);
          dpif_netlink_set_ct_dpif_tp_attrs(&nl_tp, tp);
      }
  
  out:
      return err;
  }
  
  /* Returns 0 if all the sub timeout policies are deleted or not exist in the
   * kernel.  Returns 1 if any sub timeout policy deletion failed. */
  static int
  dpif_netlink_ct_del_timeout_policy(struct dpif *dpif OVS_UNUSED,
                                     uint32_t tp_id)
  {
      int ret = 0;
  
      for (int i = 0; i < ARRAY_SIZE(tp_protos); ++i) {
          char *nl_tp_name;
          dpif_netlink_format_tp_name(tp_id, tp_protos[i].l3num,
                                      tp_protos[i].l4num, &nl_tp_name);
          int err = nl_ct_del_timeout_policy(nl_tp_name);
          if (err == ENOENT) {
              err = 0;
          }
          if (err) {
              static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(6, 6);
              VLOG_INFO_RL(&rl, "failed to delete timeout policy %s (%s)",
                           nl_tp_name, ovs_strerror(err));
              ret = 1;
          }
          free(nl_tp_name);
      }
  
      return ret;
  }
  
  struct dpif_netlink_ct_timeout_policy_dump_state {
      struct nl_ct_timeout_policy_dump_state *nl_dump_state;
      struct hmap tp_dump_map;
  };
  
  struct dpif_netlink_tp_dump_node {
      struct      hmap_node hmap_node;      /* node in tp_dump_map. */
      struct      ct_dpif_timeout_policy *tp;
      uint32_t    l3_l4_present;
  };
  
  static struct dpif_netlink_tp_dump_node *
  get_dpif_netlink_tp_dump_node_by_tp_id(uint32_t tp_id,
                                         struct hmap *tp_dump_map)
  {
      struct dpif_netlink_tp_dump_node *tp_dump_node;
  
      HMAP_FOR_EACH_WITH_HASH (tp_dump_node, hmap_node, hash_int(tp_id, 0),
                               tp_dump_map) {
          if (tp_dump_node->tp->id == tp_id) {
              return tp_dump_node;
          }
      }
      return NULL;
  }
  
  static void
  update_dpif_netlink_tp_dump_node(
      const struct nl_ct_timeout_policy *nl_tp,
      struct dpif_netlink_tp_dump_node *tp_dump_node)
  {
      dpif_netlink_set_ct_dpif_tp_attrs(nl_tp, tp_dump_node->tp);
      for (int i = 0; i < DPIF_NL_TP_MAX; ++i) {
          if (nl_tp->l3num == tp_protos[i].l3num &&
              nl_tp->l4num == tp_protos[i].l4num) {
              tp_dump_node->l3_l4_present |= 1 << i;
              break;
          }
      }
  }
  
  static int
  dpif_netlink_ct_timeout_policy_dump_start(struct dpif *dpif OVS_UNUSED,
                                            void **statep)
  {
      struct dpif_netlink_ct_timeout_policy_dump_state *dump_state;
  
      *statep = dump_state = xzalloc(sizeof *dump_state);
      int err = nl_ct_timeout_policy_dump_start(&dump_state->nl_dump_state);
      if (err) {
          free(dump_state);
          return err;
      }
      hmap_init(&dump_state->tp_dump_map);
      return 0;
  }
  
  static void
  get_and_cleanup_tp_dump_node(struct hmap *hmap,
                               struct dpif_netlink_tp_dump_node *tp_dump_node,
                               struct ct_dpif_timeout_policy *tp)
  {
      hmap_remove(hmap, &tp_dump_node->hmap_node);
      *tp = *tp_dump_node->tp;
      free(tp_dump_node->tp);
      free(tp_dump_node);
  }
  
  static int
  dpif_netlink_ct_timeout_policy_dump_next(struct dpif *dpif OVS_UNUSED,
                                           void *state,
                                           struct ct_dpif_timeout_policy *tp)
  {
      struct dpif_netlink_ct_timeout_policy_dump_state *dump_state = state;
      struct dpif_netlink_tp_dump_node *tp_dump_node;
      int err;
  
      /* Dumps all the timeout policies in the kernel. */
      do {
          struct nl_ct_timeout_policy nl_tp;
          uint32_t tp_id;
  
          err =  nl_ct_timeout_policy_dump_next(dump_state->nl_dump_state,
                                                &nl_tp);
          if (err) {
              break;
          }
  
          /* We only interest in OVS installed timeout policies. */
          if (!ovs_scan(nl_tp.name, NL_TP_NAME_PREFIX"%"PRIu32, &tp_id)) {
              continue;
          }
  
          tp_dump_node = get_dpif_netlink_tp_dump_node_by_tp_id(
                              tp_id, &dump_state->tp_dump_map);
          if (!tp_dump_node) {
              tp_dump_node = xzalloc(sizeof *tp_dump_node);
              tp_dump_node->tp = xzalloc(sizeof *tp_dump_node->tp);
              tp_dump_node->tp->id = tp_id;
              hmap_insert(&dump_state->tp_dump_map, &tp_dump_node->hmap_node,
                          hash_int(tp_id, 0));
          }
  
          update_dpif_netlink_tp_dump_node(&nl_tp, tp_dump_node);
  
          /* Returns one ct_dpif_timeout_policy if we gather all the L3/L4
           * sub-pieces. */
          if (tp_dump_node->l3_l4_present == DPIF_NL_ALL_TP) {
              get_and_cleanup_tp_dump_node(&dump_state->tp_dump_map,
                                           tp_dump_node, tp);
              break;
          }
      } while (true);
  
      /* Dump the incomplete timeout policies. */
      if (err == EOF) {
          if (!hmap_is_empty(&dump_state->tp_dump_map)) {
              struct hmap_node *hmap_node = hmap_first(&dump_state->tp_dump_map);
              tp_dump_node = CONTAINER_OF(hmap_node,
                                          struct dpif_netlink_tp_dump_node,
                                          hmap_node);
              get_and_cleanup_tp_dump_node(&dump_state->tp_dump_map,
                                           tp_dump_node, tp);
              return 0;
          }
      }
  
      return err;
  }
  
  static int
  dpif_netlink_ct_timeout_policy_dump_done(struct dpif *dpif OVS_UNUSED,
                                           void *state)
  {
      struct dpif_netlink_ct_timeout_policy_dump_state *dump_state = state;
      struct dpif_netlink_tp_dump_node *tp_dump_node;
  
      int err = nl_ct_timeout_policy_dump_done(dump_state->nl_dump_state);
      HMAP_FOR_EACH_POP (tp_dump_node, hmap_node, &dump_state->tp_dump_map) {
          free(tp_dump_node->tp);
          free(tp_dump_node);
      }
      hmap_destroy(&dump_state->tp_dump_map);
      free(dump_state);
      return err;
  }
  #endif
  
  
  /* Meters */
  
  /* Set of supported meter flags */
  #define DP_SUPPORTED_METER_FLAGS_MASK \
      (OFPMF13_STATS | OFPMF13_PKTPS | OFPMF13_KBPS | OFPMF13_BURST)
  
  /* Meter support was introduced in Linux 4.15.  In some versions of
   * Linux 4.15, 4.16, and 4.17, there was a bug that never set the id
   * when the meter was created, so all meters essentially had an id of
   * zero.  Check for that condition and disable meters on those kernels. */
  static bool probe_broken_meters(struct dpif *);
  
  static void
  dpif_netlink_meter_init(struct dpif_netlink *dpif, struct ofpbuf *buf,
                          void *stub, size_t size, uint32_t command)
  {
      ofpbuf_use_stub(buf, stub, size);
  
      nl_msg_put_genlmsghdr(buf, 0, ovs_meter_family, NLM_F_REQUEST | NLM_F_ECHO,
                            command, OVS_METER_VERSION);
  
      struct ovs_header *ovs_header;
      ovs_header = ofpbuf_put_uninit(buf, sizeof *ovs_header);
      ovs_header->dp_ifindex = dpif->dp_ifindex;
  }
  
  /* Execute meter 'request' in the kernel datapath.  If the command
   * fails, returns a positive errno value.  Otherwise, stores the reply
   * in '*replyp', parses the policy according to 'reply_policy' into the
   * array of Netlink attribute in 'a', and returns 0.  On success, the
   * caller is responsible for calling ofpbuf_delete() on '*replyp'
   * ('replyp' will contain pointers into 'a'). */
  static int
  dpif_netlink_meter_transact(struct ofpbuf *request, struct ofpbuf **replyp,
                              const struct nl_policy *reply_policy,
                              struct nlattr **a, size_t size_a)
  {
      int error = nl_transact(NETLINK_GENERIC, request, replyp);
      ofpbuf_uninit(request);
  
      if (error) {
          return error;
      }
  
      struct nlmsghdr *nlmsg = ofpbuf_try_pull(*replyp, sizeof *nlmsg);
      struct genlmsghdr *genl = ofpbuf_try_pull(*replyp, sizeof *genl);
      struct ovs_header *ovs_header = ofpbuf_try_pull(*replyp,
                                                      sizeof *ovs_header);
      if (!nlmsg || !genl || !ovs_header
          || nlmsg->nlmsg_type != ovs_meter_family
          || !nl_policy_parse(*replyp, 0, reply_policy, a, size_a)) {
          static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
          VLOG_DBG_RL(&rl,
                      "Kernel module response to meter tranaction is invalid");
          return EINVAL;
      }
      return 0;
  }
  
  static void
  dpif_netlink_meter_get_features(const struct dpif *dpif_,
                                  struct ofputil_meter_features *features)
  {
      if (probe_broken_meters(CONST_CAST(struct dpif *, dpif_))) {
          features = NULL;
          return;
      }
  
      struct ofpbuf buf, *msg;
      uint64_t stub[1024 / 8];
  
      static const struct nl_policy ovs_meter_features_policy[] = {
          [OVS_METER_ATTR_MAX_METERS] = { .type = NL_A_U32 },
          [OVS_METER_ATTR_MAX_BANDS] = { .type = NL_A_U32 },
          [OVS_METER_ATTR_BANDS] = { .type = NL_A_NESTED, .optional = true },
      };
      struct nlattr *a[ARRAY_SIZE(ovs_meter_features_policy)];
  
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      dpif_netlink_meter_init(dpif, &buf, stub, sizeof stub,
                              OVS_METER_CMD_FEATURES);
      if (dpif_netlink_meter_transact(&buf, &msg, ovs_meter_features_policy, a,
                                      ARRAY_SIZE(ovs_meter_features_policy))) {
          static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
          VLOG_INFO_RL(&rl,
                    "dpif_netlink_meter_transact OVS_METER_CMD_FEATURES failed");
          return;
      }
  
      features->max_meters = nl_attr_get_u32(a[OVS_METER_ATTR_MAX_METERS]);
      features->max_bands = nl_attr_get_u32(a[OVS_METER_ATTR_MAX_BANDS]);
  
      /* Bands is a nested attribute of zero or more nested
       * band attributes.  */
      if (a[OVS_METER_ATTR_BANDS]) {
          const struct nlattr *nla;
          size_t left;
  
          NL_NESTED_FOR_EACH (nla, left, a[OVS_METER_ATTR_BANDS]) {
              const struct nlattr *band_nla;
              size_t band_left;
  
              NL_NESTED_FOR_EACH (band_nla, band_left, nla) {
                  if (nl_attr_type(band_nla) == OVS_BAND_ATTR_TYPE) {
                      if (nl_attr_get_size(band_nla) == sizeof(uint32_t)) {
                          switch (nl_attr_get_u32(band_nla)) {
                          case OVS_METER_BAND_TYPE_DROP:
                              features->band_types |= 1 << OFPMBT13_DROP;
                              break;
                          }
                      }
                  }
              }
          }
      }
      features->capabilities = DP_SUPPORTED_METER_FLAGS_MASK;
  
      ofpbuf_delete(msg);
  }
  
  static int
  dpif_netlink_meter_set__(struct dpif *dpif_, ofproto_meter_id meter_id,
                           struct ofputil_meter_config *config)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct ofpbuf buf, *msg;
      uint64_t stub[1024 / 8];
  
      static const struct nl_policy ovs_meter_set_response_policy[] = {
          [OVS_METER_ATTR_ID] = { .type = NL_A_U32 },
      };
      struct nlattr *a[ARRAY_SIZE(ovs_meter_set_response_policy)];
  
      if (config->flags & ~DP_SUPPORTED_METER_FLAGS_MASK) {
          return EBADF; /* Unsupported flags set */
      }
  
      for (size_t i = 0; i < config->n_bands; i++) {
          switch (config->bands[i].type) {
          case OFPMBT13_DROP:
              break;
          default:
              return ENODEV; /* Unsupported band type */
          }
      }
  
      dpif_netlink_meter_init(dpif, &buf, stub, sizeof stub, OVS_METER_CMD_SET);
  
      nl_msg_put_u32(&buf, OVS_METER_ATTR_ID, meter_id.uint32);
  
      if (config->flags & OFPMF13_KBPS) {
          nl_msg_put_flag(&buf, OVS_METER_ATTR_KBPS);
      }
  
      size_t bands_offset = nl_msg_start_nested(&buf, OVS_METER_ATTR_BANDS);
      /* Bands */
      for (size_t i = 0; i < config->n_bands; ++i) {
          struct ofputil_meter_band * band = &config->bands[i];
          uint32_t band_type;
  
          size_t band_offset = nl_msg_start_nested(&buf, OVS_BAND_ATTR_UNSPEC);
  
          switch (band->type) {
          case OFPMBT13_DROP:
              band_type = OVS_METER_BAND_TYPE_DROP;
              break;
          default:
              band_type = OVS_METER_BAND_TYPE_UNSPEC;
          }
          nl_msg_put_u32(&buf, OVS_BAND_ATTR_TYPE, band_type);
          nl_msg_put_u32(&buf, OVS_BAND_ATTR_RATE, band->rate);
          nl_msg_put_u32(&buf, OVS_BAND_ATTR_BURST,
                         config->flags & OFPMF13_BURST ?
                         band->burst_size : band->rate);
          nl_msg_end_nested(&buf, band_offset);
      }
      nl_msg_end_nested(&buf, bands_offset);
  
      int error = dpif_netlink_meter_transact(&buf, &msg,
                                      ovs_meter_set_response_policy, a,
                                      ARRAY_SIZE(ovs_meter_set_response_policy));
      if (error) {
          static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
          VLOG_INFO_RL(&rl,
                       "dpif_netlink_meter_transact OVS_METER_CMD_SET failed");
          return error;
      }
  
      if (nl_attr_get_u32(a[OVS_METER_ATTR_ID]) != meter_id.uint32) {
          static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
          VLOG_INFO_RL(&rl,
                       "Kernel returned a different meter id than requested");
      }
      ofpbuf_delete(msg);
      return 0;
  }
  
  static int
  dpif_netlink_meter_set(struct dpif *dpif_, ofproto_meter_id meter_id,
                         struct ofputil_meter_config *config)
  {
      if (probe_broken_meters(dpif_)) {
          return ENOMEM;
      }
  
      return dpif_netlink_meter_set__(dpif_, meter_id, config);
  }
  
  /* Retrieve statistics and/or delete meter 'meter_id'.  Statistics are
   * stored in 'stats', if it is not null.  If 'command' is
   * OVS_METER_CMD_DEL, the meter is deleted and statistics are optionally
   * retrieved.  If 'command' is OVS_METER_CMD_GET, then statistics are
   * simply retrieved. */
  static int
  dpif_netlink_meter_get_stats(const struct dpif *dpif_,
                               ofproto_meter_id meter_id,
                               struct ofputil_meter_stats *stats,
                               uint16_t max_bands,
                               enum ovs_meter_cmd command)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct ofpbuf buf, *msg;
      uint64_t stub[1024 / 8];
  
      static const struct nl_policy ovs_meter_stats_policy[] = {
          [OVS_METER_ATTR_ID] = { .type = NL_A_U32, .optional = true},
          [OVS_METER_ATTR_STATS] = { NL_POLICY_FOR(struct ovs_flow_stats),
                                     .optional = true},
          [OVS_METER_ATTR_BANDS] = { .type = NL_A_NESTED, .optional = true },
      };
      struct nlattr *a[ARRAY_SIZE(ovs_meter_stats_policy)];
  
      dpif_netlink_meter_init(dpif, &buf, stub, sizeof stub, command);
  
      nl_msg_put_u32(&buf, OVS_METER_ATTR_ID, meter_id.uint32);
  
      int error = dpif_netlink_meter_transact(&buf, &msg,
                                              ovs_meter_stats_policy, a,
                                              ARRAY_SIZE(ovs_meter_stats_policy));
      if (error) {
          static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
          VLOG_INFO_RL(&rl, "dpif_netlink_meter_transact %s failed",
                       command == OVS_METER_CMD_GET ? "get" : "del");
          return error;
      }
  
      if (stats
          && a[OVS_METER_ATTR_ID]
          && a[OVS_METER_ATTR_STATS]
          && nl_attr_get_u32(a[OVS_METER_ATTR_ID]) == meter_id.uint32) {
          /* return stats */
          const struct ovs_flow_stats *stat;
          const struct nlattr *nla;
          size_t left;
  
          stat = nl_attr_get(a[OVS_METER_ATTR_STATS]);
          stats->packet_in_count = get_32aligned_u64(&stat->n_packets);
          stats->byte_in_count = get_32aligned_u64(&stat->n_bytes);
  
          if (a[OVS_METER_ATTR_BANDS]) {
              size_t n_bands = 0;
              NL_NESTED_FOR_EACH (nla, left, a[OVS_METER_ATTR_BANDS]) {
                  const struct nlattr *band_nla;
                  band_nla = nl_attr_find_nested(nla, OVS_BAND_ATTR_STATS);
                  if (band_nla && nl_attr_get_size(band_nla) \
                                  == sizeof(struct ovs_flow_stats)) {
                      stat = nl_attr_get(band_nla);
  
                      if (n_bands < max_bands) {
                          stats->bands[n_bands].packet_count
                              = get_32aligned_u64(&stat->n_packets);
                          stats->bands[n_bands].byte_count
                              = get_32aligned_u64(&stat->n_bytes);
                          ++n_bands;
                      }
                  } else {
                      stats->bands[n_bands].packet_count = 0;
                      stats->bands[n_bands].byte_count = 0;
                      ++n_bands;
                  }
              }
              stats->n_bands = n_bands;
          } else {
              /* For a non-existent meter, return 0 stats. */
              stats->n_bands = 0;
          }
      }
  
      ofpbuf_delete(msg);
      return error;
  }
  
  static int
  dpif_netlink_meter_get(const struct dpif *dpif, ofproto_meter_id meter_id,
                         struct ofputil_meter_stats *stats, uint16_t max_bands)
  {
      return dpif_netlink_meter_get_stats(dpif, meter_id, stats, max_bands,
                                          OVS_METER_CMD_GET);
  }
  
  static int
  dpif_netlink_meter_del(struct dpif *dpif, ofproto_meter_id meter_id,
                         struct ofputil_meter_stats *stats, uint16_t max_bands)
  {
      return dpif_netlink_meter_get_stats(dpif, meter_id, stats, max_bands,
                                          OVS_METER_CMD_DEL);
  }
  
  static bool
  probe_broken_meters__(struct dpif *dpif)
  {
      /* This test is destructive if a probe occurs while ovs-vswitchd is
       * running (e.g., an ovs-dpctl meter command is called), so choose a
       * random high meter id to make this less likely to occur. */
      ofproto_meter_id id1 = { 54545401 };
      ofproto_meter_id id2 = { 54545402 };
      struct ofputil_meter_band band = {OFPMBT13_DROP, 0, 1, 0};
      struct ofputil_meter_config config1 = { 1, OFPMF13_KBPS, 1, &band};
      struct ofputil_meter_config config2 = { 2, OFPMF13_KBPS, 1, &band};
  
      /* Try adding two meters and make sure that they both come back with
       * the proper meter id.  Use the "__" version so that we don't cause
       * a recurve deadlock. */
      dpif_netlink_meter_set__(dpif, id1, &config1);
      dpif_netlink_meter_set__(dpif, id2, &config2);
  
      if (dpif_netlink_meter_get(dpif, id1, NULL, 0)
          || dpif_netlink_meter_get(dpif, id2, NULL, 0)) {
          VLOG_INFO("The kernel module has a broken meter implementation.");
          return true;
      }
  
      dpif_netlink_meter_del(dpif, id1, NULL, 0);
      dpif_netlink_meter_del(dpif, id2, NULL, 0);
  
      return false;
  }
  
  static bool
  probe_broken_meters(struct dpif *dpif)
  {
      /* This is a once-only test because currently OVS only has at most a single
       * Netlink capable datapath on any given platform. */
      static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
  
      static bool broken_meters = false;
      if (ovsthread_once_start(&once)) {
          broken_meters = probe_broken_meters__(dpif);
          ovsthread_once_done(&once);
      }
      return broken_meters;
  }
  
  const struct dpif_class dpif_netlink_class = {
      "system",
      false,                      /* cleanup_required */
      NULL,                       /* init */
      dpif_netlink_enumerate,
      NULL,
      dpif_netlink_open,
      dpif_netlink_close,
      dpif_netlink_destroy,
      dpif_netlink_run,
      NULL,                       /* wait */
      dpif_netlink_get_stats,
      dpif_netlink_port_add,
      dpif_netlink_port_del,
      NULL,                       /* port_set_config */
      dpif_netlink_port_query_by_number,
      dpif_netlink_port_query_by_name,
      dpif_netlink_port_get_pid,
      dpif_netlink_port_dump_start,
      dpif_netlink_port_dump_next,
      dpif_netlink_port_dump_done,
      dpif_netlink_port_poll,
      dpif_netlink_port_poll_wait,
      dpif_netlink_flow_flush,
      dpif_netlink_flow_dump_create,
      dpif_netlink_flow_dump_destroy,
      dpif_netlink_flow_dump_thread_create,
      dpif_netlink_flow_dump_thread_destroy,
      dpif_netlink_flow_dump_next,
      dpif_netlink_operate,
      dpif_netlink_recv_set,
      dpif_netlink_handlers_set,
      NULL,                       /* set_config */
      dpif_netlink_queue_to_priority,
      dpif_netlink_recv,
      dpif_netlink_recv_wait,
      dpif_netlink_recv_purge,
      NULL,                       /* register_dp_purge_cb */
      NULL,                       /* register_upcall_cb */
      NULL,                       /* enable_upcall */
      NULL,                       /* disable_upcall */
      dpif_netlink_get_datapath_version, /* get_datapath_version */
      dpif_netlink_ct_dump_start,
      dpif_netlink_ct_dump_next,
      dpif_netlink_ct_dump_done,
      dpif_netlink_ct_flush,
      NULL,                       /* ct_set_maxconns */
      NULL,                       /* ct_get_maxconns */
      NULL,                       /* ct_get_nconns */
      NULL,                       /* ct_set_tcp_seq_chk */
      NULL,                       /* ct_get_tcp_seq_chk */
      dpif_netlink_ct_set_limits,
      dpif_netlink_ct_get_limits,
      dpif_netlink_ct_del_limits,
      dpif_netlink_ct_set_timeout_policy,
      dpif_netlink_ct_get_timeout_policy,
      dpif_netlink_ct_del_timeout_policy,
      dpif_netlink_ct_timeout_policy_dump_start,
      dpif_netlink_ct_timeout_policy_dump_next,
      dpif_netlink_ct_timeout_policy_dump_done,
      dpif_netlink_ct_get_timeout_policy_name,
      NULL,                       /* ipf_set_enabled */
      NULL,                       /* ipf_set_min_frag */
      NULL,                       /* ipf_set_max_nfrags */
      NULL,                       /* ipf_get_status */
      NULL,                       /* ipf_dump_start */
      NULL,                       /* ipf_dump_next */
      NULL,                       /* ipf_dump_done */
      dpif_netlink_meter_get_features,
      dpif_netlink_meter_set,
      dpif_netlink_meter_get,
      dpif_netlink_meter_del,
  };
  
  static int
  dpif_netlink_init(void)
  {
      static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
      static int error;
  
      if (ovsthread_once_start(&once)) {
          error = nl_lookup_genl_family(OVS_DATAPATH_FAMILY,
                                        &ovs_datapath_family);
          if (error) {
              VLOG_INFO("Generic Netlink family '%s' does not exist. "
                        "The Open vSwitch kernel module is probably not loaded.",
                        OVS_DATAPATH_FAMILY);
          }
          if (!error) {
              error = nl_lookup_genl_family(OVS_VPORT_FAMILY, &ovs_vport_family);
          }
          if (!error) {
              error = nl_lookup_genl_family(OVS_FLOW_FAMILY, &ovs_flow_family);
          }
          if (!error) {
              error = nl_lookup_genl_family(OVS_PACKET_FAMILY,
                                            &ovs_packet_family);
          }
          if (!error) {
              error = nl_lookup_genl_mcgroup(OVS_VPORT_FAMILY, OVS_VPORT_MCGROUP,
                                             &ovs_vport_mcgroup);
          }
          if (!error) {
              if (nl_lookup_genl_family(OVS_METER_FAMILY, &ovs_meter_family)) {
                  VLOG_INFO("The kernel module does not support meters.");
              }
          }
          if (nl_lookup_genl_family(OVS_CT_LIMIT_FAMILY,
                                    &ovs_ct_limit_family) < 0) {
              VLOG_INFO("Generic Netlink family '%s' does not exist. "
                        "Please update the Open vSwitch kernel module to enable "
                        "the conntrack limit feature.", OVS_CT_LIMIT_FAMILY);
          }
  
          ovs_tunnels_out_of_tree = dpif_netlink_rtnl_probe_oot_tunnels();
  
          ovsthread_once_done(&once);
      }
  
      return error;
  }
  
  bool
  dpif_netlink_is_internal_device(const char *name)
  {
      struct dpif_netlink_vport reply;
      struct ofpbuf *buf;
      int error;
  
      error = dpif_netlink_vport_get(name, &reply, &buf);
      if (!error) {
          ofpbuf_delete(buf);
      } else if (error != ENODEV && error != ENOENT) {
          VLOG_WARN_RL(&error_rl, "%s: vport query failed (%s)",
                       name, ovs_strerror(error));
      }
  
      return reply.type == OVS_VPORT_TYPE_INTERNAL;
  }
  
  /* Parses the contents of 'buf', which contains a "struct ovs_header" followed
   * by Netlink attributes, into 'vport'.  Returns 0 if successful, otherwise a
   * positive errno value.
   *
   * 'vport' will contain pointers into 'buf', so the caller should not free
   * 'buf' while 'vport' is still in use. */
  static int
  dpif_netlink_vport_from_ofpbuf(struct dpif_netlink_vport *vport,
                               const struct ofpbuf *buf)
  {
      static const struct nl_policy ovs_vport_policy[] = {
          [OVS_VPORT_ATTR_PORT_NO] = { .type = NL_A_U32 },
          [OVS_VPORT_ATTR_TYPE] = { .type = NL_A_U32 },
          [OVS_VPORT_ATTR_NAME] = { .type = NL_A_STRING, .max_len = IFNAMSIZ },
          [OVS_VPORT_ATTR_UPCALL_PID] = { .type = NL_A_UNSPEC },
          [OVS_VPORT_ATTR_STATS] = { NL_POLICY_FOR(struct ovs_vport_stats),
                                     .optional = true },
          [OVS_VPORT_ATTR_OPTIONS] = { .type = NL_A_NESTED, .optional = true },
          [OVS_VPORT_ATTR_NETNSID] = { .type = NL_A_U32, .optional = true },
      };
  
      dpif_netlink_vport_init(vport);
  
      struct ofpbuf b = ofpbuf_const_initializer(buf->data, buf->size);
      struct nlmsghdr *nlmsg = ofpbuf_try_pull(&b, sizeof *nlmsg);
      struct genlmsghdr *genl = ofpbuf_try_pull(&b, sizeof *genl);
      struct ovs_header *ovs_header = ofpbuf_try_pull(&b, sizeof *ovs_header);
  
      struct nlattr *a[ARRAY_SIZE(ovs_vport_policy)];
      if (!nlmsg || !genl || !ovs_header
          || nlmsg->nlmsg_type != ovs_vport_family
          || !nl_policy_parse(&b, 0, ovs_vport_policy, a,
                              ARRAY_SIZE(ovs_vport_policy))) {
          return EINVAL;
      }
  
      vport->cmd = genl->cmd;
      vport->dp_ifindex = ovs_header->dp_ifindex;
      vport->port_no = nl_attr_get_odp_port(a[OVS_VPORT_ATTR_PORT_NO]);
      vport->type = nl_attr_get_u32(a[OVS_VPORT_ATTR_TYPE]);
      vport->name = nl_attr_get_string(a[OVS_VPORT_ATTR_NAME]);
      if (a[OVS_VPORT_ATTR_UPCALL_PID]) {
          vport->n_upcall_pids = nl_attr_get_size(a[OVS_VPORT_ATTR_UPCALL_PID])
                                 / (sizeof *vport->upcall_pids);
          vport->upcall_pids = nl_attr_get(a[OVS_VPORT_ATTR_UPCALL_PID]);
  
      }
      if (a[OVS_VPORT_ATTR_STATS]) {
          vport->stats = nl_attr_get(a[OVS_VPORT_ATTR_STATS]);
      }
      if (a[OVS_VPORT_ATTR_OPTIONS]) {
          vport->options = nl_attr_get(a[OVS_VPORT_ATTR_OPTIONS]);
          vport->options_len = nl_attr_get_size(a[OVS_VPORT_ATTR_OPTIONS]);
      }
      if (a[OVS_VPORT_ATTR_NETNSID]) {
          netnsid_set(&vport->netnsid,
                      nl_attr_get_u32(a[OVS_VPORT_ATTR_NETNSID]));
      } else {
          netnsid_set_local(&vport->netnsid);
      }
      return 0;
  }
  
  /* Appends to 'buf' (which must initially be empty) a "struct ovs_header"
   * followed by Netlink attributes corresponding to 'vport'. */
  static void
  dpif_netlink_vport_to_ofpbuf(const struct dpif_netlink_vport *vport,
                               struct ofpbuf *buf)
  {
      struct ovs_header *ovs_header;
  
      nl_msg_put_genlmsghdr(buf, 0, ovs_vport_family, NLM_F_REQUEST | NLM_F_ECHO,
                            vport->cmd, OVS_VPORT_VERSION);
  
      ovs_header = ofpbuf_put_uninit(buf, sizeof *ovs_header);
      ovs_header->dp_ifindex = vport->dp_ifindex;
  
      if (vport->port_no != ODPP_NONE) {
          nl_msg_put_odp_port(buf, OVS_VPORT_ATTR_PORT_NO, vport->port_no);
      }
  
      if (vport->type != OVS_VPORT_TYPE_UNSPEC) {
          nl_msg_put_u32(buf, OVS_VPORT_ATTR_TYPE, vport->type);
      }
  
      if (vport->name) {
          nl_msg_put_string(buf, OVS_VPORT_ATTR_NAME, vport->name);
      }
  
      if (vport->upcall_pids) {
          nl_msg_put_unspec(buf, OVS_VPORT_ATTR_UPCALL_PID,
                            vport->upcall_pids,
                            vport->n_upcall_pids * sizeof *vport->upcall_pids);
      }
  
      if (vport->stats) {
          nl_msg_put_unspec(buf, OVS_VPORT_ATTR_STATS,
                            vport->stats, sizeof *vport->stats);
      }
  
      if (vport->options) {
          nl_msg_put_nested(buf, OVS_VPORT_ATTR_OPTIONS,
                            vport->options, vport->options_len);
      }
  }
  
  /* Clears 'vport' to "empty" values. */
  void
  dpif_netlink_vport_init(struct dpif_netlink_vport *vport)
  {
      memset(vport, 0, sizeof *vport);
      vport->port_no = ODPP_NONE;
  }
  
  /* Executes 'request' in the kernel datapath.  If the command fails, returns a
   * positive errno value.  Otherwise, if 'reply' and 'bufp' are null, returns 0
   * without doing anything else.  If 'reply' and 'bufp' are nonnull, then the
   * result of the command is expected to be an ovs_vport also, which is decoded
   * and stored in '*reply' and '*bufp'.  The caller must free '*bufp' when the
   * reply is no longer needed ('reply' will contain pointers into '*bufp'). */
  int
  dpif_netlink_vport_transact(const struct dpif_netlink_vport *request,
                              struct dpif_netlink_vport *reply,
                              struct ofpbuf **bufp)
  {
      struct ofpbuf *request_buf;
      int error;
  
      ovs_assert((reply != NULL) == (bufp != NULL));
  
      error = dpif_netlink_init();
      if (error) {
          if (reply) {
              *bufp = NULL;
              dpif_netlink_vport_init(reply);
          }
          return error;
      }
  
      request_buf = ofpbuf_new(1024);
      dpif_netlink_vport_to_ofpbuf(request, request_buf);
      error = nl_transact(NETLINK_GENERIC, request_buf, bufp);
      ofpbuf_delete(request_buf);
  
      if (reply) {
          if (!error) {
              error = dpif_netlink_vport_from_ofpbuf(reply, *bufp);
          }
          if (error) {
              dpif_netlink_vport_init(reply);
              ofpbuf_delete(*bufp);
              *bufp = NULL;
          }
      }
      return error;
  }
  
  /* Obtains information about the kernel vport named 'name' and stores it into
   * '*reply' and '*bufp'.  The caller must free '*bufp' when the reply is no
   * longer needed ('reply' will contain pointers into '*bufp').  */
  int
  dpif_netlink_vport_get(const char *name, struct dpif_netlink_vport *reply,
                         struct ofpbuf **bufp)
  {
      struct dpif_netlink_vport request;
  
      dpif_netlink_vport_init(&request);
      request.cmd = OVS_VPORT_CMD_GET;
      request.name = name;
  
      return dpif_netlink_vport_transact(&request, reply, bufp);
  }
  
  /* Parses the contents of 'buf', which contains a "struct ovs_header" followed
   * by Netlink attributes, into 'dp'.  Returns 0 if successful, otherwise a
   * positive errno value.
   *
   * 'dp' will contain pointers into 'buf', so the caller should not free 'buf'
   * while 'dp' is still in use. */
  static int
  dpif_netlink_dp_from_ofpbuf(struct dpif_netlink_dp *dp, const struct ofpbuf *buf)
  {
      static const struct nl_policy ovs_datapath_policy[] = {
          [OVS_DP_ATTR_NAME] = { .type = NL_A_STRING, .max_len = IFNAMSIZ },
          [OVS_DP_ATTR_STATS] = { NL_POLICY_FOR(struct ovs_dp_stats),
                                  .optional = true },
          [OVS_DP_ATTR_MEGAFLOW_STATS] = {
                          NL_POLICY_FOR(struct ovs_dp_megaflow_stats),
                          .optional = true },
      };
  
      dpif_netlink_dp_init(dp);
  
      struct ofpbuf b = ofpbuf_const_initializer(buf->data, buf->size);
      struct nlmsghdr *nlmsg = ofpbuf_try_pull(&b, sizeof *nlmsg);
      struct genlmsghdr *genl = ofpbuf_try_pull(&b, sizeof *genl);
      struct ovs_header *ovs_header = ofpbuf_try_pull(&b, sizeof *ovs_header);
  
      struct nlattr *a[ARRAY_SIZE(ovs_datapath_policy)];
      if (!nlmsg || !genl || !ovs_header
          || nlmsg->nlmsg_type != ovs_datapath_family
          || !nl_policy_parse(&b, 0, ovs_datapath_policy, a,
                              ARRAY_SIZE(ovs_datapath_policy))) {
          return EINVAL;
      }
  
      dp->cmd = genl->cmd;
      dp->dp_ifindex = ovs_header->dp_ifindex;
      dp->name = nl_attr_get_string(a[OVS_DP_ATTR_NAME]);
      if (a[OVS_DP_ATTR_STATS]) {
          dp->stats = nl_attr_get(a[OVS_DP_ATTR_STATS]);
      }
  
      if (a[OVS_DP_ATTR_MEGAFLOW_STATS]) {
          dp->megaflow_stats = nl_attr_get(a[OVS_DP_ATTR_MEGAFLOW_STATS]);
      }
  
      return 0;
  }
  
  /* Appends to 'buf' the Generic Netlink message described by 'dp'. */
  static void
  dpif_netlink_dp_to_ofpbuf(const struct dpif_netlink_dp *dp, struct ofpbuf *buf)
  {
      struct ovs_header *ovs_header;
  
      nl_msg_put_genlmsghdr(buf, 0, ovs_datapath_family,
                            NLM_F_REQUEST | NLM_F_ECHO, dp->cmd,
                            OVS_DATAPATH_VERSION);
  
      ovs_header = ofpbuf_put_uninit(buf, sizeof *ovs_header);
      ovs_header->dp_ifindex = dp->dp_ifindex;
  
      if (dp->name) {
          nl_msg_put_string(buf, OVS_DP_ATTR_NAME, dp->name);
      }
  
      if (dp->upcall_pid) {
          nl_msg_put_u32(buf, OVS_DP_ATTR_UPCALL_PID, *dp->upcall_pid);
      }
  
      if (dp->user_features) {
          nl_msg_put_u32(buf, OVS_DP_ATTR_USER_FEATURES, dp->user_features);
      }
  
      /* Skip OVS_DP_ATTR_STATS since we never have a reason to serialize it. */
  }
  
  /* Clears 'dp' to "empty" values. */
  static void
  dpif_netlink_dp_init(struct dpif_netlink_dp *dp)
  {
      memset(dp, 0, sizeof *dp);
  }
  
  static void
  dpif_netlink_dp_dump_start(struct nl_dump *dump)
  {
      struct dpif_netlink_dp request;
      struct ofpbuf *buf;
  
      dpif_netlink_dp_init(&request);
      request.cmd = OVS_DP_CMD_GET;
  
      buf = ofpbuf_new(1024);
      dpif_netlink_dp_to_ofpbuf(&request, buf);
      nl_dump_start(dump, NETLINK_GENERIC, buf);
      ofpbuf_delete(buf);
  }
  
  /* Executes 'request' in the kernel datapath.  If the command fails, returns a
   * positive errno value.  Otherwise, if 'reply' and 'bufp' are null, returns 0
   * without doing anything else.  If 'reply' and 'bufp' are nonnull, then the
   * result of the command is expected to be of the same form, which is decoded
   * and stored in '*reply' and '*bufp'.  The caller must free '*bufp' when the
   * reply is no longer needed ('reply' will contain pointers into '*bufp'). */
  static int
  dpif_netlink_dp_transact(const struct dpif_netlink_dp *request,
                           struct dpif_netlink_dp *reply, struct ofpbuf **bufp)
  {
      struct ofpbuf *request_buf;
      int error;
  
      ovs_assert((reply != NULL) == (bufp != NULL));
  
      request_buf = ofpbuf_new(1024);
      dpif_netlink_dp_to_ofpbuf(request, request_buf);
      error = nl_transact(NETLINK_GENERIC, request_buf, bufp);
      ofpbuf_delete(request_buf);
  
      if (reply) {
          dpif_netlink_dp_init(reply);
          if (!error) {
              error = dpif_netlink_dp_from_ofpbuf(reply, *bufp);
          }
          if (error) {
              ofpbuf_delete(*bufp);
              *bufp = NULL;
          }
      }
      return error;
  }
  
  /* Obtains information about 'dpif_' and stores it into '*reply' and '*bufp'.
   * The caller must free '*bufp' when the reply is no longer needed ('reply'
   * will contain pointers into '*bufp').  */
  static int
  dpif_netlink_dp_get(const struct dpif *dpif_, struct dpif_netlink_dp *reply,
                      struct ofpbuf **bufp)
  {
      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
      struct dpif_netlink_dp request;
  
      dpif_netlink_dp_init(&request);
      request.cmd = OVS_DP_CMD_GET;
      request.dp_ifindex = dpif->dp_ifindex;
  
      return dpif_netlink_dp_transact(&request, reply, bufp);
  }
  
  /* Parses the contents of 'buf', which contains a "struct ovs_header" followed
   * by Netlink attributes, into 'flow'.  Returns 0 if successful, otherwise a
   * positive errno value.
   *
   * 'flow' will contain pointers into 'buf', so the caller should not free 'buf'
   * while 'flow' is still in use. */
  static int
  dpif_netlink_flow_from_ofpbuf(struct dpif_netlink_flow *flow,
                                const struct ofpbuf *buf)
  {
      static const struct nl_policy ovs_flow_policy[__OVS_FLOW_ATTR_MAX] = {
          [OVS_FLOW_ATTR_KEY] = { .type = NL_A_NESTED, .optional = true },
          [OVS_FLOW_ATTR_MASK] = { .type = NL_A_NESTED, .optional = true },
          [OVS_FLOW_ATTR_ACTIONS] = { .type = NL_A_NESTED, .optional = true },
          [OVS_FLOW_ATTR_STATS] = { NL_POLICY_FOR(struct ovs_flow_stats),
                                    .optional = true },
          [OVS_FLOW_ATTR_TCP_FLAGS] = { .type = NL_A_U8, .optional = true },
          [OVS_FLOW_ATTR_USED] = { .type = NL_A_U64, .optional = true },
          [OVS_FLOW_ATTR_UFID] = { .type = NL_A_U128, .optional = true },
          /* The kernel never uses OVS_FLOW_ATTR_CLEAR. */
          /* The kernel never uses OVS_FLOW_ATTR_PROBE. */
          /* The kernel never uses OVS_FLOW_ATTR_UFID_FLAGS. */
      };
  
      dpif_netlink_flow_init(flow);
  
      struct ofpbuf b = ofpbuf_const_initializer(buf->data, buf->size);
      struct nlmsghdr *nlmsg = ofpbuf_try_pull(&b, sizeof *nlmsg);
      struct genlmsghdr *genl = ofpbuf_try_pull(&b, sizeof *genl);
      struct ovs_header *ovs_header = ofpbuf_try_pull(&b, sizeof *ovs_header);
  
      struct nlattr *a[ARRAY_SIZE(ovs_flow_policy)];
      if (!nlmsg || !genl || !ovs_header
          || nlmsg->nlmsg_type != ovs_flow_family
          || !nl_policy_parse(&b, 0, ovs_flow_policy, a,
                              ARRAY_SIZE(ovs_flow_policy))) {
          return EINVAL;
      }
      if (!a[OVS_FLOW_ATTR_KEY] && !a[OVS_FLOW_ATTR_UFID]) {
          return EINVAL;
      }
  
      flow->nlmsg_flags = nlmsg->nlmsg_flags;
      flow->dp_ifindex = ovs_header->dp_ifindex;
      if (a[OVS_FLOW_ATTR_KEY]) {
          flow->key = nl_attr_get(a[OVS_FLOW_ATTR_KEY]);
          flow->key_len = nl_attr_get_size(a[OVS_FLOW_ATTR_KEY]);
      }
  
      if (a[OVS_FLOW_ATTR_UFID]) {
          flow->ufid = nl_attr_get_u128(a[OVS_FLOW_ATTR_UFID]);
          flow->ufid_present = true;
      }
      if (a[OVS_FLOW_ATTR_MASK]) {
          flow->mask = nl_attr_get(a[OVS_FLOW_ATTR_MASK]);
          flow->mask_len = nl_attr_get_size(a[OVS_FLOW_ATTR_MASK]);
      }
      if (a[OVS_FLOW_ATTR_ACTIONS]) {
          flow->actions = nl_attr_get(a[OVS_FLOW_ATTR_ACTIONS]);
          flow->actions_len = nl_attr_get_size(a[OVS_FLOW_ATTR_ACTIONS]);
      }
      if (a[OVS_FLOW_ATTR_STATS]) {
          flow->stats = nl_attr_get(a[OVS_FLOW_ATTR_STATS]);
      }
      if (a[OVS_FLOW_ATTR_TCP_FLAGS]) {
          flow->tcp_flags = nl_attr_get(a[OVS_FLOW_ATTR_TCP_FLAGS]);
      }
      if (a[OVS_FLOW_ATTR_USED]) {
          flow->used = nl_attr_get(a[OVS_FLOW_ATTR_USED]);
      }
      return 0;
  }
  
  
  /*
   * If PACKET_TYPE attribute is present in 'data', it filters PACKET_TYPE out.
   * If the flow is not Ethernet, the OVS_KEY_ATTR_PACKET_TYPE is converted to
   * OVS_KEY_ATTR_ETHERTYPE. Puts 'data' to 'buf'.
   */
  static void
  put_exclude_packet_type(struct ofpbuf *buf, uint16_t type,
                          const struct nlattr *data, uint16_t data_len)
  {
      const struct nlattr *packet_type;
  
      packet_type = nl_attr_find__(data, data_len, OVS_KEY_ATTR_PACKET_TYPE);
  
      if (packet_type) {
          /* exclude PACKET_TYPE Netlink attribute. */
          ovs_assert(NLA_ALIGN(packet_type->nla_len) == NL_A_U32_SIZE);
          size_t packet_type_len = NL_A_U32_SIZE;
          size_t first_chunk_size = (uint8_t *)packet_type - (uint8_t *)data;
          size_t second_chunk_size = data_len - first_chunk_size
                                     - packet_type_len;
          struct nlattr *next_attr = nl_attr_next(packet_type);
          size_t ofs;
  
          ofs = nl_msg_start_nested(buf, type);
          nl_msg_put(buf, data, first_chunk_size);
          nl_msg_put(buf, next_attr, second_chunk_size);
          if (!nl_attr_find__(data, data_len, OVS_KEY_ATTR_ETHERNET)) {
              ovs_be16 pt = pt_ns_type_be(nl_attr_get_be32(packet_type));
              const struct nlattr *nla;
  
              nla = nl_attr_find(buf, ofs + NLA_HDRLEN, OVS_KEY_ATTR_ETHERTYPE);
              if (nla) {
                  ovs_be16 *ethertype;
  
                  ethertype = CONST_CAST(ovs_be16 *, nl_attr_get(nla));
                  *ethertype = pt;
              } else {
                  nl_msg_put_be16(buf, OVS_KEY_ATTR_ETHERTYPE, pt);
              }
          }
          nl_msg_end_nested(buf, ofs);
      } else {
          nl_msg_put_unspec(buf, type, data, data_len);
      }
  }
  
  /* Appends to 'buf' (which must initially be empty) a "struct ovs_header"
   * followed by Netlink attributes corresponding to 'flow'. */
  static void
  dpif_netlink_flow_to_ofpbuf(const struct dpif_netlink_flow *flow,
                              struct ofpbuf *buf)
  {
      struct ovs_header *ovs_header;
  
      nl_msg_put_genlmsghdr(buf, 0, ovs_flow_family,
                            NLM_F_REQUEST | flow->nlmsg_flags,
                            flow->cmd, OVS_FLOW_VERSION);
  
      ovs_header = ofpbuf_put_uninit(buf, sizeof *ovs_header);
      ovs_header->dp_ifindex = flow->dp_ifindex;
  
      if (flow->ufid_present) {
          nl_msg_put_u128(buf, OVS_FLOW_ATTR_UFID, flow->ufid);
      }
      if (flow->ufid_terse) {
          nl_msg_put_u32(buf, OVS_FLOW_ATTR_UFID_FLAGS,
                         OVS_UFID_F_OMIT_KEY | OVS_UFID_F_OMIT_MASK
                         | OVS_UFID_F_OMIT_ACTIONS);
      }
      if (!flow->ufid_terse || !flow->ufid_present) {
          if (flow->key_len) {
              put_exclude_packet_type(buf, OVS_FLOW_ATTR_KEY, flow->key,
                                             flow->key_len);
          }
          if (flow->mask_len) {
              put_exclude_packet_type(buf, OVS_FLOW_ATTR_MASK, flow->mask,
                                             flow->mask_len);
          }
          if (flow->actions || flow->actions_len) {
              nl_msg_put_unspec(buf, OVS_FLOW_ATTR_ACTIONS,
                                flow->actions, flow->actions_len);
          }
      }
  
      /* We never need to send these to the kernel. */
      ovs_assert(!flow->stats);
      ovs_assert(!flow->tcp_flags);
      ovs_assert(!flow->used);
  
      if (flow->clear) {
          nl_msg_put_flag(buf, OVS_FLOW_ATTR_CLEAR);
      }
      if (flow->probe) {
          nl_msg_put_flag(buf, OVS_FLOW_ATTR_PROBE);
      }
  }
  
  /* Clears 'flow' to "empty" values. */
  static void
  dpif_netlink_flow_init(struct dpif_netlink_flow *flow)
  {
      memset(flow, 0, sizeof *flow);
  }
  
  /* Executes 'request' in the kernel datapath.  If the command fails, returns a
   * positive errno value.  Otherwise, if 'reply' and 'bufp' are null, returns 0
   * without doing anything else.  If 'reply' and 'bufp' are nonnull, then the
   * result of the command is expected to be a flow also, which is decoded and
   * stored in '*reply' and '*bufp'.  The caller must free '*bufp' when the reply
   * is no longer needed ('reply' will contain pointers into '*bufp'). */
  static int
  dpif_netlink_flow_transact(struct dpif_netlink_flow *request,
                             struct dpif_netlink_flow *reply,
                             struct ofpbuf **bufp)
  {
      struct ofpbuf *request_buf;
      int error;
  
      ovs_assert((reply != NULL) == (bufp != NULL));
  
      if (reply) {
          request->nlmsg_flags |= NLM_F_ECHO;
      }
  
      request_buf = ofpbuf_new(1024);
      dpif_netlink_flow_to_ofpbuf(request, request_buf);
      error = nl_transact(NETLINK_GENERIC, request_buf, bufp);
      ofpbuf_delete(request_buf);
  
      if (reply) {
          if (!error) {
              error = dpif_netlink_flow_from_ofpbuf(reply, *bufp);
          }
          if (error) {
              dpif_netlink_flow_init(reply);
              ofpbuf_delete(*bufp);
              *bufp = NULL;
          }
      }
      return error;
  }
  
  static void
  dpif_netlink_flow_get_stats(const struct dpif_netlink_flow *flow,
                              struct dpif_flow_stats *stats)
  {
      if (flow->stats) {
          stats->n_packets = get_32aligned_u64(&flow->stats->n_packets);
          stats->n_bytes = get_32aligned_u64(&flow->stats->n_bytes);
      } else {
          stats->n_packets = 0;
          stats->n_bytes = 0;
      }
      stats->used = flow->used ? get_32aligned_u64(flow->used) : 0;
      stats->tcp_flags = flow->tcp_flags ? *flow->tcp_flags : 0;
  }
  
  /* Logs information about a packet that was recently lost in 'ch' (in
   * 'dpif_'). */
  static void
  report_loss(struct dpif_netlink *dpif, struct dpif_channel *ch, uint32_t ch_idx,
              uint32_t handler_id)
  {
      static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
      struct ds s;
  
      if (VLOG_DROP_WARN(&rl)) {
          return;
      }
  
      ds_init(&s);
      if (ch->last_poll != LLONG_MIN) {
          ds_put_format(&s, " (last polled %lld ms ago)",
                        time_msec() - ch->last_poll);
      }
  
      VLOG_WARN("%s: lost packet on port channel %u of handler %u",
                dpif_name(&dpif->dpif), ch_idx, handler_id);
      ds_destroy(&s);
  }
  