text: /*
   * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 Nicira, Inc.
   * Copyright (c) 2009 InMon Corp.
   *
   * 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 "ofproto-dpif-sflow.h"
  #include <inttypes.h>
  #include <sys/resource.h>
  #include <sys/socket.h>
  #include <net/if.h>
  #include <stdlib.h>
  #include "collectors.h"
  #include "compiler.h"
  #include "dpif.h"
  #include "hash.h"
  #include "openvswitch/hmap.h"
  #include "netdev.h"
  #include "netlink.h"
  #include "openvswitch/ofpbuf.h"
  #include "ofproto.h"
  #include "packets.h"
  #include "openvswitch/poll-loop.h"
  #include "ovs-router.h"
  #include "route-table.h"
  #include "sflow_api.h"
  #include "socket-util.h"
  #include "timeval.h"
  #include "openvswitch/vlog.h"
  #include "lib/odp-util.h"
  #include "lib/unaligned.h"
  #include "ofproto-provider.h"
  #include "lacp.h"
  
  VLOG_DEFINE_THIS_MODULE(sflow);
  
  static struct ovs_mutex mutex;
  
  /* This global var is used to determine which sFlow
     sub-agent should send the datapath counters. */
  #define SFLOW_GC_SUBID_UNCLAIMED (uint32_t)-1
  static uint32_t sflow_global_counters_subid = SFLOW_GC_SUBID_UNCLAIMED;
  
  /*
   * The enum dpif_sflow_tunnel_type is to declare the types supported
   */
  enum dpif_sflow_tunnel_type {
      DPIF_SFLOW_TUNNEL_UNKNOWN = 0,
      DPIF_SFLOW_TUNNEL_VXLAN,
      DPIF_SFLOW_TUNNEL_GRE,
      DPIF_SFLOW_TUNNEL_LISP,
      DPIF_SFLOW_TUNNEL_GENEVE
  };
  
  struct dpif_sflow_port {
      struct hmap_node hmap_node; /* In struct dpif_sflow's "ports" hmap. */
      SFLDataSource_instance dsi; /* sFlow library's notion of port number. */
      struct ofport *ofport;      /* To retrive port stats. */
      odp_port_t odp_port;
      enum dpif_sflow_tunnel_type tunnel_type;
  };
  
  struct dpif_sflow {
      struct collectors *collectors;
      SFLAgent *sflow_agent;
      struct ofproto_sflow_options *options;
      time_t next_tick;
      size_t n_flood, n_all;
      struct hmap ports;          /* Contains "struct dpif_sflow_port"s. */
      uint32_t probability;
      struct ovs_refcount ref_cnt;
  };
  
  static void dpif_sflow_del_port__(struct dpif_sflow *,
                                    struct dpif_sflow_port *);
  
  #define RECEIVER_INDEX 1
  
  static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  
  static bool
  ofproto_sflow_options_equal(const struct ofproto_sflow_options *a,
                           const struct ofproto_sflow_options *b)
  {
      return (sset_equals(&a->targets, &b->targets)
              && a->sampling_rate == b->sampling_rate
              && a->polling_interval == b->polling_interval
              && a->header_len == b->header_len
              && a->sub_id == b->sub_id
              && nullable_string_is_equal(a->agent_device, b->agent_device)
              && nullable_string_is_equal(a->control_ip, b->control_ip));
  }
  
  static struct ofproto_sflow_options *
  ofproto_sflow_options_clone(const struct ofproto_sflow_options *old)
  {
      struct ofproto_sflow_options *new = xmemdup(old, sizeof *old);
      sset_clone(&new->targets, &old->targets);
      new->agent_device = nullable_xstrdup(old->agent_device);
      new->control_ip = nullable_xstrdup(old->control_ip);
      return new;
  }
  
  static void
  ofproto_sflow_options_destroy(struct ofproto_sflow_options *options)
  {
      if (options) {
          sset_destroy(&options->targets);
          free(options->agent_device);
          free(options->control_ip);
          free(options);
      }
  }
  
  /* sFlow library callback to allocate memory. */
  static void *
  sflow_agent_alloc_cb(void *magic OVS_UNUSED, SFLAgent *agent OVS_UNUSED,
                       size_t bytes)
  {
      return xzalloc(bytes);
  }
  
  /* sFlow library callback to free memory. */
  static int
  sflow_agent_free_cb(void *magic OVS_UNUSED, SFLAgent *agent OVS_UNUSED,
                      void *obj)
  {
      free(obj);
      return 0;
  }
  
  /* sFlow library callback to report error. */
  static void
  sflow_agent_error_cb(void *magic OVS_UNUSED, SFLAgent *agent OVS_UNUSED,
                       char *msg)
  {
      VLOG_WARN("sFlow agent error: %s", msg);
  }
  
  /* sFlow library callback to send datagram. */
  static void
  sflow_agent_send_packet_cb(void *ds_, SFLAgent *agent OVS_UNUSED,
                             SFLReceiver *receiver OVS_UNUSED, u_char *pkt,
                             uint32_t pktLen)
  {
      struct dpif_sflow *ds = ds_;
      collectors_send(ds->collectors, pkt, pktLen);
  }
  
  static struct dpif_sflow_port *
  dpif_sflow_find_port(const struct dpif_sflow *ds, odp_port_t odp_port)
      OVS_REQUIRES(mutex)
  {
      struct dpif_sflow_port *dsp;
  
      HMAP_FOR_EACH_IN_BUCKET (dsp, hmap_node, hash_odp_port(odp_port),
                               &ds->ports) {
          if (dsp->odp_port == odp_port) {
              return dsp;
          }
      }
      return NULL;
  }
  
  /* Call to get the datapath stats. Modeled after the dpctl utility.
   *
   * It might be more efficient for this module to be given a handle it can use
   * to get these stats more efficiently, but this is only going to be called
   * once every 20-30 seconds.  Return number of datapaths found (normally expect
   * 1). */
  static int
  sflow_get_dp_stats(struct dpif_sflow *ds OVS_UNUSED,
                     struct dpif_dp_stats *dp_totals)
  {
      struct sset types;
      const char *type;
      int count = 0;
  
      memset(dp_totals, 0, sizeof *dp_totals);
      sset_init(&types);
      dp_enumerate_types(&types);
      SSET_FOR_EACH (type, &types) {
          struct sset names;
          const char *name;
          sset_init(&names);
          if (dp_enumerate_names(type, &names) == 0) {
              SSET_FOR_EACH (name, &names) {
                  struct dpif *dpif;
                  if (dpif_open(name, type, &dpif) == 0) {
                      struct dpif_dp_stats dp_stats;
                      if (dpif_get_dp_stats(dpif, &dp_stats) == 0) {
                          count++;
                          dp_totals->n_hit += dp_stats.n_hit;
                          dp_totals->n_missed += dp_stats.n_missed;
                          dp_totals->n_lost += dp_stats.n_lost;
                          dp_totals->n_flows += dp_stats.n_flows;
                          dp_totals->n_mask_hit += dp_stats.n_mask_hit;
                          dp_totals->n_masks += dp_stats.n_masks;
                      }
                      dpif_close(dpif);
                  }
              }
              sset_destroy(&names);
          }
      }
      sset_destroy(&types);
      return count;
  }
  
  /* If there are multiple bridges defined then we need some
     minimal artibration to decide which one should send the
     global counters.  This function allows each sub-agent to
     ask if he should do it or not. */
  static bool
  sflow_global_counters_subid_test(uint32_t subid)
      OVS_REQUIRES(mutex)
  {
      if (sflow_global_counters_subid == SFLOW_GC_SUBID_UNCLAIMED) {
          /* The role is up for grabs. */
          sflow_global_counters_subid = subid;
      }
      return (sflow_global_counters_subid == subid);
  }
  
  static void
  sflow_global_counters_subid_clear(uint32_t subid)
      OVS_REQUIRES(mutex)
  {
      if (sflow_global_counters_subid == subid) {
          /* The sub-agent that was sending global counters
             is going away, so reset to allow another
             to take over. */
          sflow_global_counters_subid = SFLOW_GC_SUBID_UNCLAIMED;
      }
  }
  
  static void
  sflow_agent_get_global_counters(void *ds_, SFLPoller *poller,
                                  SFL_COUNTERS_SAMPLE_TYPE *cs)
      OVS_REQUIRES(mutex)
  {
      struct dpif_sflow *ds = ds_;
      SFLCounters_sample_element dp_elem, res_elem;
      struct dpif_dp_stats dp_totals;
      struct rusage usage;
  
      if (!sflow_global_counters_subid_test(poller->agent->subId)) {
          /* Another sub-agent is currently responsible for this. */
          return;
      }
  
      /* datapath stats */
      if (sflow_get_dp_stats(ds, &dp_totals)) {
          dp_elem.tag = SFLCOUNTERS_OVSDP;
          dp_elem.counterBlock.ovsdp.n_hit = dp_totals.n_hit;
          dp_elem.counterBlock.ovsdp.n_missed = dp_totals.n_missed;
          dp_elem.counterBlock.ovsdp.n_lost = dp_totals.n_lost;
          dp_elem.counterBlock.ovsdp.n_mask_hit = dp_totals.n_mask_hit;
          dp_elem.counterBlock.ovsdp.n_flows = dp_totals.n_flows;
          dp_elem.counterBlock.ovsdp.n_masks = dp_totals.n_masks;
          SFLADD_ELEMENT(cs, &dp_elem);
      }
  
      /* resource usage */
      getrusage(RUSAGE_SELF, &usage);
      res_elem.tag = SFLCOUNTERS_APP_RESOURCES;
      res_elem.counterBlock.appResources.user_time
          = timeval_to_msec(&usage.ru_utime);
      res_elem.counterBlock.appResources.system_time
          = timeval_to_msec(&usage.ru_stime);
      res_elem.counterBlock.appResources.mem_used = (usage.ru_maxrss * 1024);
      SFL_UNDEF_GAUGE(res_elem.counterBlock.appResources.mem_max);
      SFL_UNDEF_GAUGE(res_elem.counterBlock.appResources.fd_open);
      SFL_UNDEF_GAUGE(res_elem.counterBlock.appResources.fd_max);
      SFL_UNDEF_GAUGE(res_elem.counterBlock.appResources.conn_open);
      SFL_UNDEF_GAUGE(res_elem.counterBlock.appResources.conn_max);
  
      SFLADD_ELEMENT(cs, &res_elem);
      sfl_poller_writeCountersSample(poller, cs);
  }
  
  static void
  sflow_agent_get_counters(void *ds_, SFLPoller *poller,
                           SFL_COUNTERS_SAMPLE_TYPE *cs)
      OVS_REQUIRES(mutex)
  {
      struct dpif_sflow *ds = ds_;
      SFLCounters_sample_element elem, lacp_elem, of_elem, name_elem;
      SFLCounters_sample_element eth_elem;
      enum netdev_features current;
      struct dpif_sflow_port *dsp;
      SFLIf_counters *counters;
      SFLEthernet_counters* eth_counters;
      struct netdev_stats stats;
      enum netdev_flags flags;
      struct lacp_slave_stats lacp_stats;
      const char *ifName;
  
      dsp = dpif_sflow_find_port(ds, u32_to_odp(poller->bridgePort));
      if (!dsp) {
          return;
      }
  
      elem.tag = SFLCOUNTERS_GENERIC;
      counters = &elem.counterBlock.generic;
      counters->ifIndex = SFL_DS_INDEX(poller->dsi);
      counters->ifType = 6;
      if (!netdev_get_features(dsp->ofport->netdev, &current, NULL, NULL, NULL)) {
          /* The values of ifDirection come from MAU MIB (RFC 2668): 0 = unknown,
             1 = full-duplex, 2 = half-duplex, 3 = in, 4=out */
          counters->ifSpeed = netdev_features_to_bps(current, 0);
          counters->ifDirection = (netdev_features_is_full_duplex(current)
                                   ? 1 : 2);
      } else {
          counters->ifSpeed = 100000000;
          counters->ifDirection = 0;
      }
      if (!netdev_get_flags(dsp->ofport->netdev, &flags) && flags & NETDEV_UP) {
          counters->ifStatus = 1; /* ifAdminStatus up. */
          if (netdev_get_carrier(dsp->ofport->netdev)) {
              counters->ifStatus |= 2; /* ifOperStatus us. */
          }
      } else {
          counters->ifStatus = 0;  /* Down. */
      }
  
      /* XXX
         1. Is the multicast counter filled in?
         2. Does the multicast counter include broadcasts?
         3. Does the rx_packets counter include multicasts/broadcasts?
      */
      ofproto_port_get_stats(dsp->ofport, &stats);
      counters->ifInOctets = stats.rx_bytes;
      counters->ifInUcastPkts = stats.rx_packets;
      counters->ifInMulticastPkts = stats.multicast;
      counters->ifInBroadcastPkts = stats.rx_broadcast_packets;
      counters->ifInDiscards = stats.rx_dropped;
      counters->ifInErrors = stats.rx_errors;
      counters->ifInUnknownProtos = -1;
      counters->ifOutOctets = stats.tx_bytes;
      counters->ifOutUcastPkts = stats.tx_packets;
      counters->ifOutMulticastPkts = stats.tx_multicast_packets;
      counters->ifOutBroadcastPkts = stats.tx_broadcast_packets;
      counters->ifOutDiscards = stats.tx_dropped;
      counters->ifOutErrors = stats.tx_errors;
      counters->ifPromiscuousMode = 0;
  
      SFLADD_ELEMENT(cs, &elem);
  
      /* Include LACP counters and identifiers if this port is part of a LAG. */
      if (ofproto_port_get_lacp_stats(dsp->ofport, &lacp_stats) == 0) {
          memset(&lacp_elem, 0, sizeof lacp_elem);
          lacp_elem.tag = SFLCOUNTERS_LACP;
          lacp_elem.counterBlock.lacp.actorSystemID =
          lacp_stats.dot3adAggPortActorSystemID;
          lacp_elem.counterBlock.lacp.partnerSystemID =
          lacp_stats.dot3adAggPortPartnerOperSystemID;
          lacp_elem.counterBlock.lacp.attachedAggID =
              lacp_stats.dot3adAggPortAttachedAggID;
          lacp_elem.counterBlock.lacp.portState.v.actorAdmin =
              lacp_stats.dot3adAggPortActorAdminState;
          lacp_elem.counterBlock.lacp.portState.v.actorOper =
              lacp_stats.dot3adAggPortActorOperState;
          lacp_elem.counterBlock.lacp.portState.v.partnerAdmin =
              lacp_stats.dot3adAggPortPartnerAdminState;
          lacp_elem.counterBlock.lacp.portState.v.partnerOper =
              lacp_stats.dot3adAggPortPartnerOperState;
          lacp_elem.counterBlock.lacp.LACPDUsRx =
              lacp_stats.dot3adAggPortStatsLACPDUsRx;
          SFL_UNDEF_COUNTER(lacp_elem.counterBlock.lacp.markerPDUsRx);
          SFL_UNDEF_COUNTER(lacp_elem.counterBlock.lacp.markerResponsePDUsRx);
          SFL_UNDEF_COUNTER(lacp_elem.counterBlock.lacp.unknownRx);
          lacp_elem.counterBlock.lacp.illegalRx =
              lacp_stats.dot3adAggPortStatsIllegalRx;
          lacp_elem.counterBlock.lacp.LACPDUsTx =
              lacp_stats.dot3adAggPortStatsLACPDUsTx;
          SFL_UNDEF_COUNTER(lacp_elem.counterBlock.lacp.markerPDUsTx);
          SFL_UNDEF_COUNTER(lacp_elem.counterBlock.lacp.markerResponsePDUsTx);
          SFLADD_ELEMENT(cs, &lacp_elem);
      }
  
      /* Include Port name. */
      if ((ifName = netdev_get_name(dsp->ofport->netdev)) != NULL) {
          memset(&name_elem, 0, sizeof name_elem);
          name_elem.tag = SFLCOUNTERS_PORTNAME;
          name_elem.counterBlock.portName.portName.str = (char *)ifName;
          name_elem.counterBlock.portName.portName.len = strlen(ifName);
          SFLADD_ELEMENT(cs, &name_elem);
      }
  
      /* Include OpenFlow DPID and openflow port number. */
      memset(&of_elem, 0, sizeof of_elem);
      of_elem.tag = SFLCOUNTERS_OPENFLOWPORT;
      of_elem.counterBlock.ofPort.datapath_id =
          ofproto_get_datapath_id(dsp->ofport->ofproto);
      of_elem.counterBlock.ofPort.port_no =
        (OVS_FORCE uint32_t)dsp->ofport->ofp_port;
      SFLADD_ELEMENT(cs, &of_elem);
  
      /* Include ethernet counters */
      memset(&eth_elem, 0, sizeof eth_elem);
      eth_elem.tag = SFLCOUNTERS_ETHERNET;
      eth_counters = &eth_elem.counterBlock.ethernet;
      eth_counters->dot3StatsAlignmentErrors = stats.rx_frame_errors;
      eth_counters->dot3StatsFCSErrors = stats.rx_crc_errors;
      eth_counters->dot3StatsFrameTooLongs = stats.rx_oversize_errors;
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsSingleCollisionFrames);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsMultipleCollisionFrames);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsSQETestErrors);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsDeferredTransmissions);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsLateCollisions);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsExcessiveCollisions);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsInternalMacTransmitErrors);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsCarrierSenseErrors);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsInternalMacReceiveErrors);
      SFL_UNDEF_COUNTER(eth_counters->dot3StatsSymbolErrors);
      SFLADD_ELEMENT(cs, &eth_elem);
  
      sfl_poller_writeCountersSample(poller, cs);
  }
  
  /* Obtains an address to use for the local sFlow agent and stores it into
   * '*agent_addr'.  Returns true if successful, false on failure.
   *
   * The sFlow agent address should be a local IP address that is persistent and
   * reachable over the network, if possible.  The IP address associated with
   * 'agent_device' is used if it has one, and otherwise 'control_ip', the IP
   * address used to talk to the controller.  If the agent device is not
   * specified then it is figured out by taking a look at the routing table based
   * on 'targets'. */
  static bool
  sflow_choose_agent_address(const char *agent_device,
                             const struct sset *targets,
                             const char *control_ip,
                             SFLAddress *agent_addr)
  {
      struct in6_addr ip;
  
      if (agent_device) {
          /* If 'agent_device' is the name of a network device, use its IP
           * address. */
          if (!netdev_get_ip_by_name(agent_device, &ip)) {
              goto success;
          }
  
          /* If 'agent_device' is itself an IP address, use it. */
          struct sockaddr_storage ss;
          if (inet_parse_address(agent_device, &ss)) {
              ip = ss_get_address(&ss);
              goto success;
          }
      }
  
      /* Otherwise, use an appropriate local IP address for one of the
       * collectors' remote IP addresses. */
      const char *target;
      SSET_FOR_EACH (target, targets) {
          struct sockaddr_storage ss;
          if (inet_parse_active(target, SFL_DEFAULT_COLLECTOR_PORT, &ss)) {
              /* sFlow only supports target in default routing table with
               * packet mark zero.
               */
              ip = ss_get_address(&ss);
  
              struct in6_addr gw, src = in6addr_any;
              char name[IFNAMSIZ];
              if (ovs_router_lookup(0, &ip, name, &src, &gw)) {
                  goto success;
              }
          }
      }
  
      struct sockaddr_storage ss;
      if (control_ip && inet_parse_address(control_ip, &ss)) {
          ip = ss_get_address(&ss);
          goto success;
      }
  
      VLOG_ERR("could not determine IP address for sFlow agent");
      return false;
  
  success:
      memset(agent_addr, 0, sizeof *agent_addr);
      if (IN6_IS_ADDR_V4MAPPED(&ip)) {
          agent_addr->type = SFLADDRESSTYPE_IP_V4;
          agent_addr->address.ip_v4.addr
              = (OVS_FORCE uint32_t) in6_addr_get_mapped_ipv4(&ip);
      } else {
          agent_addr->type = SFLADDRESSTYPE_IP_V6;
          memcpy(agent_addr->address.ip_v6.addr, ip.s6_addr,
                 sizeof agent_addr->address.ip_v6.addr);
      }
      return true;
  }
  
  static void
  dpif_sflow_clear__(struct dpif_sflow *ds) OVS_REQUIRES(mutex)
  {
      if (ds->sflow_agent) {
          sflow_global_counters_subid_clear(ds->sflow_agent->subId);
          sfl_agent_release(ds->sflow_agent);
          free(ds->sflow_agent);
          ds->sflow_agent = NULL;
      }
      collectors_destroy(ds->collectors);
      ds->collectors = NULL;
      ofproto_sflow_options_destroy(ds->options);
      ds->options = NULL;
  
      /* Turn off sampling to save CPU cycles. */
      ds->probability = 0;
  }
  
  void
  dpif_sflow_clear(struct dpif_sflow *ds) OVS_EXCLUDED(mutex)
  {
      ovs_mutex_lock(&mutex);
      dpif_sflow_clear__(ds);
      ovs_mutex_unlock(&mutex);
  }
  
  bool
  dpif_sflow_is_enabled(const struct dpif_sflow *ds) OVS_EXCLUDED(mutex)
  {
      bool enabled;
  
      ovs_mutex_lock(&mutex);
      enabled = ds->collectors != NULL;
      ovs_mutex_unlock(&mutex);
      return enabled;
  }
  
  struct dpif_sflow *
  dpif_sflow_create(void)
  {
      static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
      struct dpif_sflow *ds;
  
      if (ovsthread_once_start(&once)) {
          ovs_mutex_init_recursive(&mutex);
          ovsthread_once_done(&once);
      }
  
      ds = xcalloc(1, sizeof *ds);
      ds->next_tick = time_now() + 1;
      hmap_init(&ds->ports);
      ds->probability = 0;
      ovs_refcount_init(&ds->ref_cnt);
  
      return ds;
  }
  
  struct dpif_sflow *
  dpif_sflow_ref(const struct dpif_sflow *ds_)
  {
      struct dpif_sflow *ds = CONST_CAST(struct dpif_sflow *, ds_);
      if (ds) {
          ovs_refcount_ref(&ds->ref_cnt);
      }
      return ds;
  }
  
  /* 32-bit fraction of packets to sample with.  A value of 0 samples no packets,
   * a value of %UINT32_MAX samples all packets and intermediate values sample
   * intermediate fractions of packets. */
  uint32_t
  dpif_sflow_get_probability(const struct dpif_sflow *ds) OVS_EXCLUDED(mutex)
  {
      uint32_t probability;
      ovs_mutex_lock(&mutex);
      probability = ds->probability;
      ovs_mutex_unlock(&mutex);
      return probability;
  }
  
  void
  dpif_sflow_unref(struct dpif_sflow *ds) OVS_EXCLUDED(mutex)
  {
      if (ds && ovs_refcount_unref_relaxed(&ds->ref_cnt) == 1) {
          struct dpif_sflow_port *dsp, *next;
  
          dpif_sflow_clear(ds);
          HMAP_FOR_EACH_SAFE (dsp, next, hmap_node, &ds->ports) {
              dpif_sflow_del_port__(ds, dsp);
          }
          hmap_destroy(&ds->ports);
          free(ds);
      }
  }
  
  static void
  dpif_sflow_add_poller(struct dpif_sflow *ds, struct dpif_sflow_port *dsp)
      OVS_REQUIRES(mutex)
  {
      SFLPoller *poller = sfl_agent_addPoller(ds->sflow_agent, &dsp->dsi, ds,
                                              sflow_agent_get_counters);
      sfl_poller_set_sFlowCpInterval(poller, ds->options->polling_interval);
      sfl_poller_set_sFlowCpReceiver(poller, RECEIVER_INDEX);
      sfl_poller_set_bridgePort(poller, odp_to_u32(dsp->odp_port));
  }
  
  static enum dpif_sflow_tunnel_type
  dpif_sflow_tunnel_type(struct ofport *ofport) {
      const char *type = netdev_get_type(ofport->netdev);
      if (type) {
          if (strcmp(type, "gre") == 0) {
              return DPIF_SFLOW_TUNNEL_GRE;
          } else if (strcmp(type, "vxlan") == 0) {
              return DPIF_SFLOW_TUNNEL_VXLAN;
          } else if (strcmp(type, "lisp") == 0) {
              return DPIF_SFLOW_TUNNEL_LISP;
          } else if (strcmp(type, "geneve") == 0) {
              return DPIF_SFLOW_TUNNEL_GENEVE;
          }
      }
      return DPIF_SFLOW_TUNNEL_UNKNOWN;
  }
  
  static uint8_t
  dpif_sflow_tunnel_proto(enum dpif_sflow_tunnel_type tunnel_type)
  {
      /* Default to 0 (IPPROTO_IP), meaning "unknown". */
      uint8_t ipproto = 0;
      switch(tunnel_type) {
  
      case DPIF_SFLOW_TUNNEL_GRE:
          ipproto = IPPROTO_GRE;
          break;
  
      case DPIF_SFLOW_TUNNEL_VXLAN:
      case DPIF_SFLOW_TUNNEL_LISP:
      case DPIF_SFLOW_TUNNEL_GENEVE:
          ipproto = IPPROTO_UDP;
  
      case DPIF_SFLOW_TUNNEL_UNKNOWN:
          break;
      }
      return ipproto;
  }
  
  void
  dpif_sflow_add_port(struct dpif_sflow *ds, struct ofport *ofport,
                      odp_port_t odp_port) OVS_EXCLUDED(mutex)
  {
      struct dpif_sflow_port *dsp;
      int ifindex;
      enum dpif_sflow_tunnel_type tunnel_type;
  
      ovs_mutex_lock(&mutex);
      dpif_sflow_del_port(ds, odp_port);
  
      tunnel_type = dpif_sflow_tunnel_type(ofport);
      ifindex = netdev_get_ifindex(ofport->netdev);
  
      if (ifindex <= 0
          && tunnel_type == DPIF_SFLOW_TUNNEL_UNKNOWN) {
          /* Not an ifindex port, and not a tunnel port either
           * so do not add a cross-reference to it here.
           */
          goto out;
      }
  
      /* Add to table of ports. */
      dsp = xmalloc(sizeof *dsp);
      dsp->ofport = ofport;
      dsp->odp_port = odp_port;
      dsp->tunnel_type = tunnel_type;
      hmap_insert(&ds->ports, &dsp->hmap_node, hash_odp_port(odp_port));
  
      if (ifindex > 0) {
          /* Add poller for ports that have ifindex. */
          SFL_DS_SET(dsp->dsi, SFL_DSCLASS_IFINDEX, ifindex, 0);
          if (ds->sflow_agent) {
              dpif_sflow_add_poller(ds, dsp);
          }
      } else {
          /* Record "ifindex unknown" for the others */
          SFL_DS_SET(dsp->dsi, SFL_DSCLASS_IFINDEX, 0, 0);
      }
  
  out:
      ovs_mutex_unlock(&mutex);
  }
  
  static void
  dpif_sflow_del_port__(struct dpif_sflow *ds, struct dpif_sflow_port *dsp)
      OVS_REQUIRES(mutex)
  {
      if (ds->sflow_agent
          && SFL_DS_INDEX(dsp->dsi)) {
          sfl_agent_removePoller(ds->sflow_agent, &dsp->dsi);
          sfl_agent_removeSampler(ds->sflow_agent, &dsp->dsi);
      }
      hmap_remove(&ds->ports, &dsp->hmap_node);
      free(dsp);
  }
  
  void
  dpif_sflow_del_port(struct dpif_sflow *ds, odp_port_t odp_port)
      OVS_EXCLUDED(mutex)
  {
      struct dpif_sflow_port *dsp;
  
      ovs_mutex_lock(&mutex);
      dsp = dpif_sflow_find_port(ds, odp_port);
      if (dsp) {
          dpif_sflow_del_port__(ds, dsp);
      }
      ovs_mutex_unlock(&mutex);
  }
  
  void
  dpif_sflow_set_options(struct dpif_sflow *ds,
                         const struct ofproto_sflow_options *options)
      OVS_EXCLUDED(mutex)
  {
      struct dpif_sflow_port *dsp;
      bool options_changed;
      SFLReceiver *receiver;
      SFLAddress agentIP;
      time_t now;
      SFLDataSource_instance dsi;
      uint32_t dsIndex;
      SFLSampler *sampler;
      SFLPoller *poller;
  
      ovs_mutex_lock(&mutex);
      if (sset_is_empty(&options->targets) || !options->sampling_rate) {
          /* No point in doing any work if there are no targets or nothing to
           * sample. */
          dpif_sflow_clear__(ds);
          goto out;
      }
  
      options_changed = (!ds->options
                         || !ofproto_sflow_options_equal(options, ds->options));
  
      /* Configure collectors if options have changed or if we're shortchanged in
       * collectors (which indicates that opening one or more of the configured
       * collectors failed, so that we should retry). */
      if (options_changed
          || collectors_count(ds->collectors) < sset_count(&options->targets)) {
          collectors_destroy(ds->collectors);
          collectors_create(&options->targets, SFL_DEFAULT_COLLECTOR_PORT,
                            &ds->collectors);
          if (ds->collectors == NULL) {
              VLOG_WARN_RL(&rl, "no collectors could be initialized, "
                           "sFlow disabled");
              dpif_sflow_clear__(ds);
              goto out;
          }
      }
  
      /* Choose agent IP address and agent device (if not yet setup) */
      if (!sflow_choose_agent_address(options->agent_device,
                                      &options->targets,
                                      options->control_ip, &agentIP)) {
          dpif_sflow_clear__(ds);
          goto out;
      }
  
      /* Avoid reconfiguring if options didn't change. */
      if (!options_changed) {
          goto out;
      }
      ofproto_sflow_options_destroy(ds->options);
      ds->options = ofproto_sflow_options_clone(options);
  
      /* Create agent. */
      VLOG_INFO("creating sFlow agent %d", options->sub_id);
      if (ds->sflow_agent) {
          sflow_global_counters_subid_clear(ds->sflow_agent->subId);
          sfl_agent_release(ds->sflow_agent);
      }
      ds->sflow_agent = xcalloc(1, sizeof *ds->sflow_agent);
      now = time_wall();
      sfl_agent_init(ds->sflow_agent,
                     &agentIP,
                     options->sub_id,
                     now,         /* Boot time. */
                     now,         /* Current time. */
                     ds,          /* Pointer supplied to callbacks. */
                     sflow_agent_alloc_cb,
                     sflow_agent_free_cb,
                     sflow_agent_error_cb,
                     sflow_agent_send_packet_cb);
  
      receiver = sfl_agent_addReceiver(ds->sflow_agent);
      sfl_receiver_set_sFlowRcvrOwner(receiver, "Open vSwitch sFlow");
      sfl_receiver_set_sFlowRcvrTimeout(receiver, 0xffffffff);
  
      /* Set the sampling_rate down in the datapath. */
      ds->probability = MAX(1, UINT32_MAX / ds->options->sampling_rate);
  
      /* Add a single sampler for the bridge. This appears as a PHYSICAL_ENTITY
         because it is associated with the hypervisor, and interacts with the server
         hardware directly.  The sub_id is used to distinguish this sampler from
         others on other bridges within the same agent. */
      dsIndex = 1000 + options->sub_id;
      SFL_DS_SET(dsi, SFL_DSCLASS_PHYSICAL_ENTITY, dsIndex, 0);
      sampler = sfl_agent_addSampler(ds->sflow_agent, &dsi);
      sfl_sampler_set_sFlowFsPacketSamplingRate(sampler, ds->options->sampling_rate);
      sfl_sampler_set_sFlowFsMaximumHeaderSize(sampler, ds->options->header_len);
      sfl_sampler_set_sFlowFsReceiver(sampler, RECEIVER_INDEX);
  
      /* Add a counter poller for the bridge so we can use it to send
         global counters such as datapath cache hit/miss stats. */
      poller = sfl_agent_addPoller(ds->sflow_agent, &dsi, ds,
                                   sflow_agent_get_global_counters);
      sfl_poller_set_sFlowCpInterval(poller, ds->options->polling_interval);
      sfl_poller_set_sFlowCpReceiver(poller, RECEIVER_INDEX);
  
      /* Add pollers for the currently known ifindex-ports */
      HMAP_FOR_EACH (dsp, hmap_node, &ds->ports) {
          if (SFL_DS_INDEX(dsp->dsi)) {
              dpif_sflow_add_poller(ds, dsp);
          }
      }
  
  
  out:
      ovs_mutex_unlock(&mutex);
  }
  
  int
  dpif_sflow_odp_port_to_ifindex(const struct dpif_sflow *ds,
                                 odp_port_t odp_port) OVS_EXCLUDED(mutex)
  {
      struct dpif_sflow_port *dsp;
      int ret;
  
      ovs_mutex_lock(&mutex);
      dsp = dpif_sflow_find_port(ds, odp_port);
      ret = dsp ? SFL_DS_INDEX(dsp->dsi) : 0;
      ovs_mutex_unlock(&mutex);
      return ret;
  }
  
  static void
  dpif_sflow_tunnel_v4(uint8_t tunnel_ipproto,
                       const struct flow_tnl *tunnel,
                       SFLSampled_ipv4 *ipv4)
  
  {
      ipv4->protocol = tunnel_ipproto;
      ipv4->tos = tunnel->ip_tos;
      ipv4->src_ip.addr = (OVS_FORCE uint32_t) tunnel->ip_src;
      ipv4->dst_ip.addr = (OVS_FORCE uint32_t) tunnel->ip_dst;
      ipv4->src_port = (OVS_FORCE uint16_t) tunnel->tp_src;
      ipv4->dst_port = (OVS_FORCE uint16_t) tunnel->tp_dst;
  }
  
  static void
  dpif_sflow_push_mpls_lse(struct dpif_sflow_actions *sflow_actions,
                           ovs_be32 lse)
  {
      if (sflow_actions->mpls_stack_depth >= FLOW_MAX_MPLS_LABELS) {
          sflow_actions->mpls_err = true;
          return;
      }
  
      /* Record the new lse in host-byte-order. */
      /* BOS flag will be fixed later when we send stack to sFlow library. */
      sflow_actions->mpls_lse[sflow_actions->mpls_stack_depth++] = ntohl(lse);
  }
  
  static void
  dpif_sflow_pop_mpls_lse(struct dpif_sflow_actions *sflow_actions)
  {
      if (sflow_actions->mpls_stack_depth == 0) {
          sflow_actions->mpls_err = true;
          return;
      }
      sflow_actions->mpls_stack_depth--;
  }
  
  static void
  dpif_sflow_set_mpls(struct dpif_sflow_actions *sflow_actions,
                      const struct ovs_key_mpls *mpls_key, int n)
  {
      int ii;
      if (n > FLOW_MAX_MPLS_LABELS) {
          sflow_actions->mpls_err = true;
          return;
      }
  
      for (ii = 0; ii < n; ii++) {
          /* Reverse stack order, and use host-byte-order for each lse. */
          sflow_actions->mpls_lse[n - ii - 1] = ntohl(mpls_key[ii].mpls_lse);
      }
      sflow_actions->mpls_stack_depth = n;
  }
  
  static void
  sflow_read_tnl_push_action(const struct nlattr *attr,
                             struct dpif_sflow_actions *sflow_actions)
  {
      /* Modeled on lib/odp-util.c: format_odp_tnl_push_header */
      const struct ovs_action_push_tnl *data = nl_attr_get(attr);
      const struct eth_header *eth = (const struct eth_header *) data->header;
      const struct ip_header *ip
          = ALIGNED_CAST(const struct ip_header *, eth + 1);
  
      sflow_actions->out_port = data->out_port;
  
      /* Ethernet. */
      /* TODO: SFlow does not currently define a MAC-in-MAC
       * encapsulation structure.  We could use an extension
       * structure to report this.
       */
  
      /* IPv4 */
      /* Cannot assume alignment so just use memcpy. */
      sflow_actions->tunnel.ip_src = get_16aligned_be32(&ip->ip_src);
      sflow_actions->tunnel.ip_dst = get_16aligned_be32(&ip->ip_dst);
      sflow_actions->tunnel.ip_tos = ip->ip_tos;
      sflow_actions->tunnel.ip_ttl = ip->ip_ttl;
      /* The tnl_push action can supply the ip_protocol too. */
      sflow_actions->tunnel_ipproto = ip->ip_proto;
  
      /* Layer 4 */
      if (data->tnl_type == OVS_VPORT_TYPE_VXLAN
          || data->tnl_type == OVS_VPORT_TYPE_GENEVE) {
          const struct udp_header *udp = (const struct udp_header *) (ip + 1);
          sflow_actions->tunnel.tp_src = udp->udp_src;
          sflow_actions->tunnel.tp_dst = udp->udp_dst;
  
          if (data->tnl_type == OVS_VPORT_TYPE_VXLAN) {
              const struct vxlanhdr *vxh = (const struct vxlanhdr *) (udp + 1);
              uint64_t tun_id = ntohl(get_16aligned_be32(&vxh->vx_vni)) >> 8;
              sflow_actions->tunnel.tun_id = htonll(tun_id);
          } else {
              const struct genevehdr *gnh = (const struct genevehdr *) (udp + 1);
              uint64_t tun_id = ntohl(get_16aligned_be32(&gnh->vni)) >> 8;
              sflow_actions->tunnel.tun_id = htonll(tun_id);
          }
      } else if (data->tnl_type == OVS_VPORT_TYPE_GRE) {
          const void *l4 = ip + 1;
          const struct gre_base_hdr *greh = (const struct gre_base_hdr *) l4;
          ovs_16aligned_be32 *options = (ovs_16aligned_be32 *)(greh + 1);
          if (greh->flags & htons(GRE_CSUM)) {
              options++;
          }
          if (greh->flags & htons(GRE_KEY)) {
              uint64_t tun_id = ntohl(get_16aligned_be32(options));
              sflow_actions->tunnel.tun_id = htonll(tun_id);
          }
      }
  }
  
  static void
  sflow_read_set_action(const struct nlattr *attr,
                        struct dpif_sflow_actions *sflow_actions)
  {
      enum ovs_key_attr type = nl_attr_type(attr);
      switch (type) {
      case OVS_KEY_ATTR_ENCAP:
          if (++sflow_actions->encap_depth > 1) {
              /* Do not handle multi-encap for now. */
              sflow_actions->tunnel_err = true;
          } else {
              dpif_sflow_read_actions(NULL,
                                      nl_attr_get(attr), nl_attr_get_size(attr),
                                      sflow_actions, true);
          }
          break;
      case OVS_KEY_ATTR_PRIORITY:
      case OVS_KEY_ATTR_SKB_MARK:
      case OVS_KEY_ATTR_DP_HASH:
      case OVS_KEY_ATTR_RECIRC_ID:
          break;
  
      case OVS_KEY_ATTR_TUNNEL: {
          if (++sflow_actions->encap_depth > 1) {
              /* Do not handle multi-encap for now. */
              sflow_actions->tunnel_err = true;
          } else {
              if (odp_tun_key_from_attr(attr, &sflow_actions->tunnel)
                  == ODP_FIT_ERROR) {
                  /* Tunnel parsing error. */
                  sflow_actions->tunnel_err = true;
              }
          }
          break;
      }
  
      case OVS_KEY_ATTR_IN_PORT:
      case OVS_KEY_ATTR_ETHERNET:
      case OVS_KEY_ATTR_VLAN:
          break;
  
      case OVS_KEY_ATTR_MPLS: {
          const struct ovs_key_mpls *mpls_key = nl_attr_get(attr);
          size_t size = nl_attr_get_size(attr);
          dpif_sflow_set_mpls(sflow_actions, mpls_key, size / sizeof *mpls_key);
          break;
      }
  
      case OVS_KEY_ATTR_ETHERTYPE:
      case OVS_KEY_ATTR_IPV4:
          if (sflow_actions->encap_depth == 1) {
              const struct ovs_key_ipv4 *key = nl_attr_get(attr);
              if (key->ipv4_src) {
                  sflow_actions->tunnel.ip_src = key->ipv4_src;
              }
              if (key->ipv4_dst) {
                  sflow_actions->tunnel.ip_dst = key->ipv4_dst;
              }
              if (key->ipv4_proto) {
                  sflow_actions->tunnel_ipproto = key->ipv4_proto;
              }
              if (key->ipv4_tos) {
                  sflow_actions->tunnel.ip_tos = key->ipv4_tos;
              }
              if (key->ipv4_ttl) {
                  sflow_actions->tunnel.ip_tos = key->ipv4_ttl;
              }
          }
          break;
  
      case OVS_KEY_ATTR_IPV6:
          /* TODO: parse IPv6 encap. */
          break;
  
          /* These have the same structure and format. */
      case OVS_KEY_ATTR_TCP:
      case OVS_KEY_ATTR_UDP:
      case OVS_KEY_ATTR_SCTP:
          if (sflow_actions->encap_depth == 1) {
              const struct ovs_key_tcp *key = nl_attr_get(attr);
              if (key->tcp_src) {
                  sflow_actions->tunnel.tp_src = key->tcp_src;
              }
              if (key->tcp_dst) {
                  sflow_actions->tunnel.tp_dst = key->tcp_dst;
              }
          }
          break;
  
      case OVS_KEY_ATTR_TCP_FLAGS:
      case OVS_KEY_ATTR_ICMP:
      case OVS_KEY_ATTR_ICMPV6:
      case OVS_KEY_ATTR_ARP:
      case OVS_KEY_ATTR_ND:
      case OVS_KEY_ATTR_CT_STATE:
      case OVS_KEY_ATTR_CT_ZONE:
      case OVS_KEY_ATTR_CT_MARK:
      case OVS_KEY_ATTR_CT_LABELS:
      case OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV4:
      case OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV6:
      case OVS_KEY_ATTR_UNSPEC:
      case OVS_KEY_ATTR_PACKET_TYPE:
      case OVS_KEY_ATTR_NSH:
      case __OVS_KEY_ATTR_MAX:
      default:
          break;
      }
  }
  
  static void
  dpif_sflow_capture_input_mpls(const struct flow *flow,
                                struct dpif_sflow_actions *sflow_actions)
  {
      if (eth_type_mpls(flow->dl_type)) {
          int depth = 0;
          int ii;
          ovs_be32 lse;
          /* Calculate depth by detecting BOS. */
          for (ii = 0; ii < FLOW_MAX_MPLS_LABELS; ii++) {
              lse = flow->mpls_lse[ii];
              depth++;
              if (lse & htonl(MPLS_BOS_MASK)) {
                  break;
              }
          }
          /* Capture stack, reversing stack order, and
           * using host-byte-order for each lse. BOS flag
           * is ignored for now. It is set later when
           * the output stack is encoded.
           */
          for (ii = 0; ii < depth; ii++) {
              lse = flow->mpls_lse[ii];
              sflow_actions->mpls_lse[depth - ii - 1] = ntohl(lse);
          }
          sflow_actions->mpls_stack_depth = depth;
      }
  }
  
  void
  dpif_sflow_read_actions(const struct flow *flow,
                          const struct nlattr *actions, size_t actions_len,
                          struct dpif_sflow_actions *sflow_actions,
                          bool capture_mpls)
  {
      const struct nlattr *a;
      unsigned int left;
  
      if (actions_len == 0) {
          /* Packet dropped.*/
          return;
      }
  
      if (flow != NULL && capture_mpls == true) {
          /* Make sure the MPLS output stack
           * is seeded with the input stack.
           */
          dpif_sflow_capture_input_mpls(flow, sflow_actions);
  
          /* XXX when 802.1AD(QinQ) is supported then
           * we can do the same with VLAN stacks here
           */
      }
  
      NL_ATTR_FOR_EACH (a, left, actions, actions_len) {
          enum ovs_action_attr type = nl_attr_type(a);
          switch (type) {
          case OVS_ACTION_ATTR_OUTPUT:
              /* Capture the output port in case we need it
               * to get the output tunnel type.
               */
              sflow_actions->out_port = nl_attr_get_odp_port(a);
              break;
  
          case OVS_ACTION_ATTR_TUNNEL_POP:
              /* XXX: Do not handle this for now.  It's not clear
               * if we should start with encap_depth == 1 when we
               * see an input tunnel,  or if we should assume
               * that the input tunnel was always "popped" if it
               * was presented to us decoded in flow->tunnel?
               *
               * If we do handle this it might look like this,
               * as we clear the captured tunnel info and decrement
               * the encap_depth:
               *
               * memset(&sflow_actions->tunnel, 0, sizeof struct flow_tnl);
               * sflow_actions->tunnel_ipproto = 0;
               * --sflow_actions->encap_depth;
               *
               * but for now just disable the tunnel annotation:
               */
              sflow_actions->tunnel_err = true;
              break;
  
          case OVS_ACTION_ATTR_TUNNEL_PUSH:
              /* XXX: This actions appears to come with it's own
               * OUTPUT action, so should it be regarded as having
               * an implicit "pop" following it too?  Put another
               * way, would two tnl_push() actions in succession
               * result in a packet with two layers of encap?
               */
              if (++sflow_actions->encap_depth > 1) {
                  /* Do not handle multi-encap for now. */
                  sflow_actions->tunnel_err = true;
              } else {
                  sflow_read_tnl_push_action(a, sflow_actions);
              }
              break;
  
          case OVS_ACTION_ATTR_TRUNC:
          case OVS_ACTION_ATTR_USERSPACE:
          case OVS_ACTION_ATTR_RECIRC:
          case OVS_ACTION_ATTR_HASH:
          case OVS_ACTION_ATTR_CT:
      case OVS_ACTION_ATTR_CT_CLEAR:
          case OVS_ACTION_ATTR_METER:
              break;
  
          case OVS_ACTION_ATTR_SET_MASKED:
              /* TODO: apply mask. XXX: Are we likely to see this? */
              break;
  
          case OVS_ACTION_ATTR_SET:
              sflow_read_set_action(nl_attr_get(a), sflow_actions);
              break;
  
          case OVS_ACTION_ATTR_PUSH_VLAN:
          case OVS_ACTION_ATTR_POP_VLAN:
              /* TODO: 802.1AD(QinQ) is not supported by OVS (yet), so do not
               * construct a VLAN-stack. The sFlow user-action cookie already
               * captures the egress VLAN ID so there is nothing more to do here.
               */
              break;
  
          case OVS_ACTION_ATTR_PUSH_MPLS: {
              const struct ovs_action_push_mpls *mpls = nl_attr_get(a);
              if (mpls) {
                  dpif_sflow_push_mpls_lse(sflow_actions, mpls->mpls_lse);
              }
              break;
          }
          case OVS_ACTION_ATTR_POP_MPLS: {
              dpif_sflow_pop_mpls_lse(sflow_actions);
              break;
          }
          case OVS_ACTION_ATTR_PUSH_ETH:
          case OVS_ACTION_ATTR_POP_ETH:
              /* TODO: SFlow does not currently define a MAC-in-MAC
               * encapsulation structure.  We could use an extension
               * structure to report this.
               */
              break;
      case OVS_ACTION_ATTR_CLONE:
          if (flow != NULL) {
              dpif_sflow_read_actions(flow, nl_attr_get(a), nl_attr_get_size(a),
                                      sflow_actions, false);
          }
          break;
          case OVS_ACTION_ATTR_SAMPLE:
          case OVS_ACTION_ATTR_PUSH_NSH:
          case OVS_ACTION_ATTR_POP_NSH:
          case OVS_ACTION_ATTR_UNSPEC:
          case __OVS_ACTION_ATTR_MAX:
          default:
              break;
          }
      }
  }
  
  static void
  dpif_sflow_encode_mpls_stack(SFLLabelStack *stack,
                               uint32_t *mpls_lse_buf,
                               const struct dpif_sflow_actions *sflow_actions)
  {
      /* Put the MPLS stack back into "packet header" order,
       * and make sure the BOS flag is set correctly on the last
       * one.  Each lse is still in host-byte-order.
       */
      int ii;
      uint32_t lse;
      stack->depth = sflow_actions->mpls_stack_depth;
      stack->stack = mpls_lse_buf;
      for (ii = 0; ii < stack->depth; ii++) {
          lse = sflow_actions->mpls_lse[stack->depth - ii - 1];
          stack->stack[ii] = (lse & ~MPLS_BOS_MASK);
      }
      stack->stack[stack->depth - 1] |= MPLS_BOS_MASK;
  }
  
  /* Extract the output port count from the user action cookie.
   * See http://sflow.org/sflow_version_5.txt "Input/Output port information"
   */
  static uint32_t
  dpif_sflow_cookie_num_outputs(const struct user_action_cookie *cookie)
  {
      uint32_t format = cookie->sflow.output & 0xC0000000;
      uint32_t port_n = cookie->sflow.output & 0x3FFFFFFF;
      if (format == 0) {
          return port_n ? 1 : 0;
      }
      else if (format == 0x80000000) {
          return port_n;
      }
      return 0;
  }
  
  void
  dpif_sflow_received(struct dpif_sflow *ds, const struct dp_packet *packet,
                      const struct flow *flow, odp_port_t odp_in_port,
                      const struct user_action_cookie *cookie,
                      const struct dpif_sflow_actions *sflow_actions)
      OVS_EXCLUDED(mutex)
  {
      SFL_FLOW_SAMPLE_TYPE fs;
      SFLFlow_sample_element hdrElem;
      SFLSampled_header *header;
      SFLFlow_sample_element switchElem;
      uint8_t tnlInProto, tnlOutProto;
      SFLFlow_sample_element tnlInElem, tnlOutElem;
      SFLFlow_sample_element vniInElem, vniOutElem;
      SFLFlow_sample_element mplsElem;
      uint32_t mpls_lse_buf[FLOW_MAX_MPLS_LABELS];
      SFLSampler *sampler;
      struct dpif_sflow_port *in_dsp;
      struct dpif_sflow_port *out_dsp;
      ovs_be16 vlan_tci;
  
      ovs_mutex_lock(&mutex);
      sampler = ds->sflow_agent->samplers;
      if (!sampler) {
          goto out;
      }
  
      /* Build a flow sample. */
      memset(&fs, 0, sizeof fs);
  
      /* Look up the input ifIndex if this port has one. Otherwise just
       * leave it as 0 (meaning 'unknown') and continue. */
      in_dsp = dpif_sflow_find_port(ds, odp_in_port);
      if (in_dsp) {
          fs.input = SFL_DS_INDEX(in_dsp->dsi);
      }
  
      /* Make the assumption that the random number generator in the
       * datapath converges to the configured mean, and just increment the
       * samplePool by the configured sampling rate every time. */
      sampler->samplePool += sfl_sampler_get_sFlowFsPacketSamplingRate(sampler);
  
      /* Sampled header. */
      memset(&hdrElem, 0, sizeof hdrElem);
      hdrElem.tag = SFLFLOW_HEADER;
      header = &hdrElem.flowType.header;
      header->header_protocol = SFLHEADER_ETHERNET_ISO8023;
      /* The frame_length should include the Ethernet FCS (4 bytes),
       * but it has already been stripped,  so we need to add 4 here. */
      header->frame_length = dp_packet_size(packet) + 4;
      /* Ethernet FCS stripped off. */
      header->stripped = 4;
      header->header_length = MIN(dp_packet_size(packet),
                                  sampler->sFlowFsMaximumHeaderSize);
      header->header_bytes = dp_packet_data(packet);
  
      /* Add extended switch element. */
      memset(&switchElem, 0, sizeof(switchElem));
      switchElem.tag = SFLFLOW_EX_SWITCH;
      switchElem.flowType.sw.src_vlan = vlan_tci_to_vid(flow->vlans[0].tci);
      switchElem.flowType.sw.src_priority = vlan_tci_to_pcp(flow->vlans[0].tci);
  
      /* Retrieve data from user_action_cookie. */
      vlan_tci = cookie->sflow.vlan_tci;
      switchElem.flowType.sw.dst_vlan = vlan_tci_to_vid(vlan_tci);
      switchElem.flowType.sw.dst_priority = vlan_tci_to_pcp(vlan_tci);
  
      fs.output = cookie->sflow.output;
  
      /* Input tunnel. */
      if (flow->tunnel.ip_dst) {
          memset(&tnlInElem, 0, sizeof(tnlInElem));
          tnlInElem.tag = SFLFLOW_EX_IPV4_TUNNEL_INGRESS;
          tnlInProto = in_dsp ? dpif_sflow_tunnel_proto(in_dsp->tunnel_type) : 0;
          dpif_sflow_tunnel_v4(tnlInProto,
                               &flow->tunnel,
                               &tnlInElem.flowType.ipv4);
          SFLADD_ELEMENT(&fs, &tnlInElem);
          if (flow->tunnel.tun_id) {
              memset(&vniInElem, 0, sizeof(vniInElem));
              vniInElem.tag = SFLFLOW_EX_VNI_INGRESS;
              vniInElem.flowType.tunnel_vni.vni
                  = ntohll(flow->tunnel.tun_id);
              SFLADD_ELEMENT(&fs, &vniInElem);
          }
      }
  
      /* Output tunnel. */
      if (sflow_actions
          && sflow_actions->encap_depth == 1
          && !sflow_actions->tunnel_err
          && dpif_sflow_cookie_num_outputs(cookie) == 1) {
          tnlOutProto = sflow_actions->tunnel_ipproto;
          if (tnlOutProto == 0) {
              /* Try to infer the ip-protocol from the output port. */
              if (sflow_actions->out_port != ODPP_NONE) {
                  out_dsp = dpif_sflow_find_port(ds, sflow_actions->out_port);
                  if (out_dsp) {
                      tnlOutProto = dpif_sflow_tunnel_proto(out_dsp->tunnel_type);
                  }
              }
          }
          memset(&tnlOutElem, 0, sizeof(tnlOutElem));
          tnlOutElem.tag = SFLFLOW_EX_IPV4_TUNNEL_EGRESS;
          dpif_sflow_tunnel_v4(tnlOutProto,
                               &sflow_actions->tunnel,
                               &tnlOutElem.flowType.ipv4);
          SFLADD_ELEMENT(&fs, &tnlOutElem);
          if (sflow_actions->tunnel.tun_id) {
              memset(&vniOutElem, 0, sizeof(vniOutElem));
              vniOutElem.tag = SFLFLOW_EX_VNI_EGRESS;
              vniOutElem.flowType.tunnel_vni.vni
                  = ntohll(sflow_actions->tunnel.tun_id);
              SFLADD_ELEMENT(&fs, &vniOutElem);
          }
      }
  
      /* MPLS output label stack. */
      if (sflow_actions
          && sflow_actions->mpls_stack_depth > 0
          && !sflow_actions->mpls_err
          && dpif_sflow_cookie_num_outputs(cookie) == 1) {
          memset(&mplsElem, 0, sizeof(mplsElem));
          mplsElem.tag = SFLFLOW_EX_MPLS;
          dpif_sflow_encode_mpls_stack(&mplsElem.flowType.mpls.out_stack,
                                       mpls_lse_buf,
                                       sflow_actions);
          SFLADD_ELEMENT(&fs, &mplsElem);
      }
  
      /* Submit the flow sample to be encoded into the next datagram. */
      SFLADD_ELEMENT(&fs, &hdrElem);
      SFLADD_ELEMENT(&fs, &switchElem);
      sfl_sampler_writeFlowSample(sampler, &fs);
  
  out:
      ovs_mutex_unlock(&mutex);
  }
  
  void
  dpif_sflow_run(struct dpif_sflow *ds) OVS_EXCLUDED(mutex)
  {
      ovs_mutex_lock(&mutex);
      if (ds->collectors != NULL) {
          time_t now = time_now();
          route_table_run();
          if (now >= ds->next_tick) {
              sfl_agent_tick(ds->sflow_agent, time_wall());
              ds->next_tick = now + 1;
          }
      }
      ovs_mutex_unlock(&mutex);
  }
  
  void
  dpif_sflow_wait(struct dpif_sflow *ds) OVS_EXCLUDED(mutex)
  {
      ovs_mutex_lock(&mutex);
      if (ds->collectors != NULL) {
          poll_timer_wait_until(ds->next_tick * 1000LL);
      }
      ovs_mutex_unlock(&mutex);
  }
  