text: /*
   * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 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 <sys/types.h>
  #include "flow.h"
  #include <errno.h>
  #include <inttypes.h>
  #include <limits.h>
  #include <netinet/in.h>
  #include <netinet/icmp6.h>
  #include <netinet/ip6.h>
  #include <stdint.h>
  #include <stdlib.h>
  #include <string.h>
  #include "byte-order.h"
  #include "coverage.h"
  #include "csum.h"
  #include "dynamic-string.h"
  #include "hash.h"
  #include "jhash.h"
  #include "match.h"
  #include "ofpbuf.h"
  #include "openflow/openflow.h"
  #include "packets.h"
  #include "odp-util.h"
  #include "random.h"
  #include "unaligned.h"
  
  COVERAGE_DEFINE(flow_extract);
  COVERAGE_DEFINE(miniflow_malloc);
  
  /* U32 indices for segmented flow classification. */
  const uint8_t flow_segment_u32s[4] = {
      FLOW_SEGMENT_1_ENDS_AT / 4,
      FLOW_SEGMENT_2_ENDS_AT / 4,
      FLOW_SEGMENT_3_ENDS_AT / 4,
      FLOW_U32S
  };
  
  /* miniflow_extract() assumes the following to be true to optimize the
   * extraction process. */
  BUILD_ASSERT_DECL(offsetof(struct flow, dl_type) + 2
                    == offsetof(struct flow, vlan_tci) &&
                    offsetof(struct flow, dl_type) / 4
                    == offsetof(struct flow, vlan_tci) / 4 );
  
  BUILD_ASSERT_DECL(offsetof(struct flow, nw_frag) + 3
                    == offsetof(struct flow, nw_proto) &&
                    offsetof(struct flow, nw_tos) + 2
                    == offsetof(struct flow, nw_proto) &&
                    offsetof(struct flow, nw_ttl) + 1
                    == offsetof(struct flow, nw_proto) &&
                    offsetof(struct flow, nw_frag) / 4
                    == offsetof(struct flow, nw_tos) / 4 &&
                    offsetof(struct flow, nw_ttl) / 4
                    == offsetof(struct flow, nw_tos) / 4 &&
                    offsetof(struct flow, nw_proto) / 4
                    == offsetof(struct flow, nw_tos) / 4);
  
  /* TCP flags in the first half of a BE32, zeroes in the other half. */
  BUILD_ASSERT_DECL(offsetof(struct flow, tcp_flags) + 2
                    == offsetof(struct flow, pad2) &&
                    offsetof(struct flow, tcp_flags) / 4
                    == offsetof(struct flow, pad2) / 4);
  #if WORDS_BIGENDIAN
  #define TCP_FLAGS_BE32(tcp_ctl) ((OVS_FORCE ovs_be32)TCP_FLAGS_BE16(tcp_ctl) \
                                   << 16)
  #else
  #define TCP_FLAGS_BE32(tcp_ctl) ((OVS_FORCE ovs_be32)TCP_FLAGS_BE16(tcp_ctl))
  #endif
  
  BUILD_ASSERT_DECL(offsetof(struct flow, tp_src) + 2
                    == offsetof(struct flow, tp_dst) &&
                    offsetof(struct flow, tp_src) / 4
                    == offsetof(struct flow, tp_dst) / 4);
  
  /* Removes 'size' bytes from the head end of '*datap', of size '*sizep', which
   * must contain at least 'size' bytes of data.  Returns the first byte of data
   * removed. */
  static inline const void *
  data_pull(void **datap, size_t *sizep, size_t size)
  {
      char *data = (char *)*datap;
      *datap = data + size;
      *sizep -= size;
      return data;
  }
  
  /* If '*datap' has at least 'size' bytes of data, removes that many bytes from
   * the head end of '*datap' and returns the first byte removed.  Otherwise,
   * returns a null pointer without modifying '*datap'. */
  static inline const void *
  data_try_pull(void **datap, size_t *sizep, size_t size)
  {
      return OVS_LIKELY(*sizep >= size) ? data_pull(datap, sizep, size) : NULL;
  }
  
  /* Context for pushing data to a miniflow. */
  struct mf_ctx {
      uint64_t map;
      uint32_t *data;
      uint32_t * const end;
  };
  
  /* miniflow_push_* macros allow filling in a miniflow data values in order.
   * Assertions are needed only when the layout of the struct flow is modified.
   * 'ofs' is a compile-time constant, which allows most of the code be optimized
   * away.  Some GCC versions gave warnings on ALWAYS_INLINE, so these are
   * defined as macros. */
  
  #if (FLOW_WC_SEQ != 28)
  #define MINIFLOW_ASSERT(X) ovs_assert(X)
  BUILD_MESSAGE("FLOW_WC_SEQ changed: miniflow_extract() will have runtime "
                 "assertions enabled. Consider updating FLOW_WC_SEQ after "
                 "testing")
  #else
  #define MINIFLOW_ASSERT(X)
  #endif
  
  #define miniflow_push_uint32_(MF, OFS, VALUE)                   \
  {                                                               \
      MINIFLOW_ASSERT(MF.data < MF.end && (OFS) % 4 == 0          \
                      && !(MF.map & (UINT64_MAX << (OFS) / 4)));  \
      *MF.data++ = VALUE;                                         \
      MF.map |= UINT64_C(1) << (OFS) / 4;                         \
  }
  
  #define miniflow_push_be32_(MF, OFS, VALUE) \
      miniflow_push_uint32_(MF, OFS, (OVS_FORCE uint32_t)(VALUE))
  
  #define miniflow_push_uint16_(MF, OFS, VALUE)                   \
  {                                                               \
      MINIFLOW_ASSERT(MF.data < MF.end &&                                 \
                      (((OFS) % 4 == 0 && !(MF.map & (UINT64_MAX << (OFS) / 4))) \
                       || ((OFS) % 4 == 2 && MF.map & (UINT64_C(1) << (OFS) / 4) \
                           && !(MF.map & (UINT64_MAX << ((OFS) / 4 + 1)))))); \
                                                                          \
      if ((OFS) % 4 == 0) {                                               \
          *(uint16_t *)MF.data = VALUE;                                   \
          MF.map |= UINT64_C(1) << (OFS) / 4;                             \
      } else if ((OFS) % 4 == 2) {                                        \
          *((uint16_t *)MF.data + 1) = VALUE;                             \
          MF.data++;                                                      \
      }                                                                   \
  }
  
  #define miniflow_push_be16_(MF, OFS, VALUE)             \
      miniflow_push_uint16_(MF, OFS, (OVS_FORCE uint16_t)VALUE);
  
  /* Data at 'valuep' may be unaligned. */
  #define miniflow_push_words_(MF, OFS, VALUEP, N_WORDS)          \
  {                                                               \
      int ofs32 = (OFS) / 4;                                      \
                                                                          \
      MINIFLOW_ASSERT(MF.data + (N_WORDS) <= MF.end && (OFS) % 4 == 0     \
                      && !(MF.map & (UINT64_MAX << ofs32)));              \
                                                                          \
      memcpy(MF.data, (VALUEP), (N_WORDS) * sizeof *MF.data);             \
      MF.data += (N_WORDS);                                               \
      MF.map |= ((UINT64_MAX >> (64 - (N_WORDS))) << ofs32);              \
  }
  
  #define miniflow_push_uint32(MF, FIELD, VALUE)                          \
      miniflow_push_uint32_(MF, offsetof(struct flow, FIELD), VALUE)
  
  #define miniflow_push_be32(MF, FIELD, VALUE)                            \
      miniflow_push_be32_(MF, offsetof(struct flow, FIELD), VALUE)
  
  #define miniflow_push_uint32_check(MF, FIELD, VALUE)                    \
      { if (OVS_LIKELY(VALUE)) {                                          \
              miniflow_push_uint32_(MF, offsetof(struct flow, FIELD), VALUE); \
          }                                                               \
      }
  
  #define miniflow_push_be32_check(MF, FIELD, VALUE)                      \
      { if (OVS_LIKELY(VALUE)) {                                          \
              miniflow_push_be32_(MF, offsetof(struct flow, FIELD), VALUE); \
          }                                                               \
      }
  
  #define miniflow_push_uint16(MF, FIELD, VALUE)                          \
      miniflow_push_uint16_(MF, offsetof(struct flow, FIELD), VALUE)
  
  #define miniflow_push_be16(MF, FIELD, VALUE)                            \
      miniflow_push_be16_(MF, offsetof(struct flow, FIELD), VALUE)
  
  #define miniflow_push_words(MF, FIELD, VALUEP, N_WORDS)                 \
      miniflow_push_words_(MF, offsetof(struct flow, FIELD), VALUEP, N_WORDS)
  
  /* Pulls the MPLS headers at '*datap' and returns the count of them. */
  static inline int
  parse_mpls(void **datap, size_t *sizep)
  {
      const struct mpls_hdr *mh;
      int count = 0;
  
      while ((mh = data_try_pull(datap, sizep, sizeof *mh))) {
          count++;
          if (mh->mpls_lse.lo & htons(1 << MPLS_BOS_SHIFT)) {
              break;
          }
      }
      return MIN(count, FLOW_MAX_MPLS_LABELS);
  }
  
  static inline ovs_be16
  parse_vlan(void **datap, size_t *sizep)
  {
      const struct eth_header *eth = *datap;
  
      struct qtag_prefix {
          ovs_be16 eth_type;      /* ETH_TYPE_VLAN */
          ovs_be16 tci;
      };
  
      data_pull(datap, sizep, ETH_ADDR_LEN * 2);
  
      if (eth->eth_type == htons(ETH_TYPE_VLAN)) {
          if (OVS_LIKELY(*sizep
                         >= sizeof(struct qtag_prefix) + sizeof(ovs_be16))) {
              const struct qtag_prefix *qp = data_pull(datap, sizep, sizeof *qp);
              return qp->tci | htons(VLAN_CFI);
          }
      }
      return 0;
  }
  
  static inline ovs_be16
  parse_ethertype(void **datap, size_t *sizep)
  {
      const struct llc_snap_header *llc;
      ovs_be16 proto;
  
      proto = *(ovs_be16 *) data_pull(datap, sizep, sizeof proto);
      if (OVS_LIKELY(ntohs(proto) >= ETH_TYPE_MIN)) {
          return proto;
      }
  
      if (OVS_UNLIKELY(*sizep < sizeof *llc)) {
          return htons(FLOW_DL_TYPE_NONE);
      }
  
      llc = *datap;
      if (OVS_UNLIKELY(llc->llc.llc_dsap != LLC_DSAP_SNAP
                       || llc->llc.llc_ssap != LLC_SSAP_SNAP
                       || llc->llc.llc_cntl != LLC_CNTL_SNAP
                       || memcmp(llc->snap.snap_org, SNAP_ORG_ETHERNET,
                                 sizeof llc->snap.snap_org))) {
          return htons(FLOW_DL_TYPE_NONE);
      }
  
      data_pull(datap, sizep, sizeof *llc);
  
      if (OVS_LIKELY(ntohs(llc->snap.snap_type) >= ETH_TYPE_MIN)) {
          return llc->snap.snap_type;
      }
  
      return htons(FLOW_DL_TYPE_NONE);
  }
  
  static inline bool
  parse_icmpv6(void **datap, size_t *sizep, const struct icmp6_hdr *icmp,
               const struct in6_addr **nd_target,
               uint8_t arp_buf[2][ETH_ADDR_LEN])
  {
      if (icmp->icmp6_code == 0 &&
          (icmp->icmp6_type == ND_NEIGHBOR_SOLICIT ||
           icmp->icmp6_type == ND_NEIGHBOR_ADVERT)) {
  
          *nd_target = data_try_pull(datap, sizep, sizeof **nd_target);
          if (OVS_UNLIKELY(!*nd_target)) {
              return false;
          }
  
          while (*sizep >= 8) {
              /* The minimum size of an option is 8 bytes, which also is
               * the size of Ethernet link-layer options. */
              const struct nd_opt_hdr *nd_opt = *datap;
              int opt_len = nd_opt->nd_opt_len * 8;
  
              if (!opt_len || opt_len > *sizep) {
                  goto invalid;
              }
  
              /* Store the link layer address if the appropriate option is
               * provided.  It is considered an error if the same link
               * layer option is specified twice. */
              if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LINKADDR
                      && opt_len == 8) {
                  if (OVS_LIKELY(eth_addr_is_zero(arp_buf[0]))) {
                      memcpy(arp_buf[0], nd_opt + 1, ETH_ADDR_LEN);
                  } else {
                      goto invalid;
                  }
              } else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LINKADDR
                      && opt_len == 8) {
                  if (OVS_LIKELY(eth_addr_is_zero(arp_buf[1]))) {
                      memcpy(arp_buf[1], nd_opt + 1, ETH_ADDR_LEN);
                  } else {
                      goto invalid;
                  }
              }
  
              if (OVS_UNLIKELY(!data_try_pull(datap, sizep, opt_len))) {
                  goto invalid;
              }
          }
      }
  
      return true;
  
  invalid:
      return false;
  }
  
  /* Initializes 'flow' members from 'packet' and 'md'
   *
   * Initializes 'packet' header l2 pointer to the start of the Ethernet
   * header, and the layer offsets as follows:
   *
   *    - packet->l2_5_ofs to the start of the MPLS shim header, or UINT16_MAX
   *      when there is no MPLS shim header.
   *
   *    - packet->l3_ofs to just past the Ethernet header, or just past the
   *      vlan_header if one is present, to the first byte of the payload of the
   *      Ethernet frame.  UINT16_MAX if the frame is too short to contain an
   *      Ethernet header.
   *
   *    - packet->l4_ofs to just past the IPv4 header, if one is present and
   *      has at least the content used for the fields of interest for the flow,
   *      otherwise UINT16_MAX.
   */
  void
  flow_extract(struct ofpbuf *packet, const struct pkt_metadata *md,
               struct flow *flow)
  {
      struct {
          struct miniflow mf;
          uint32_t buf[FLOW_U32S];
      } m;
  
      COVERAGE_INC(flow_extract);
  
      miniflow_initialize(&m.mf, m.buf);
      miniflow_extract(packet, md, &m.mf);
      miniflow_expand(&m.mf, flow);
  }
  
  /* Caller is responsible for initializing 'dst' with enough storage for
   * FLOW_U32S * 4 bytes. */
  void
  miniflow_extract(struct ofpbuf *packet, const struct pkt_metadata *md,
                   struct miniflow *dst)
  {
      void *data = ofpbuf_data(packet);
      size_t size = ofpbuf_size(packet);
      uint32_t *values = miniflow_values(dst);
      struct mf_ctx mf = { 0, values, values + FLOW_U32S };
      char *l2;
      ovs_be16 dl_type;
      uint8_t nw_frag, nw_tos, nw_ttl, nw_proto;
  
      /* Metadata. */
      if (md) {
          if (md->tunnel.ip_dst) {
              miniflow_push_words(mf, tunnel, &md->tunnel,
                                  sizeof md->tunnel / 4);
          }
          miniflow_push_uint32_check(mf, skb_priority, md->skb_priority);
          miniflow_push_uint32_check(mf, pkt_mark, md->pkt_mark);
          miniflow_push_uint32_check(mf, recirc_id, md->recirc_id);
          miniflow_push_uint32(mf, in_port, odp_to_u32(md->in_port.odp_port));
      }
  
      /* Initialize packet's layer pointer and offsets. */
      l2 = data;
      ofpbuf_set_frame(packet, data);
  
      /* Must have full Ethernet header to proceed. */
      if (OVS_UNLIKELY(size < sizeof(struct eth_header))) {
          goto out;
      } else {
          ovs_be16 vlan_tci;
  
          /* Link layer. */
          BUILD_ASSERT(offsetof(struct flow, dl_dst) + 6
                       == offsetof(struct flow, dl_src));
          miniflow_push_words(mf, dl_dst, data, ETH_ADDR_LEN * 2 / 4);
          /* dl_type, vlan_tci. */
          vlan_tci = parse_vlan(&data, &size);
          dl_type = parse_ethertype(&data, &size);
          miniflow_push_be16(mf, dl_type, dl_type);
          miniflow_push_be16(mf, vlan_tci, vlan_tci);
      }
  
      /* Parse mpls. */
      if (OVS_UNLIKELY(eth_type_mpls(dl_type))) {
          int count;
          const void *mpls = data;
  
          packet->l2_5_ofs = (char *)data - l2;
          count = parse_mpls(&data, &size);
          miniflow_push_words(mf, mpls_lse, mpls, count);
      }
  
      /* Network layer. */
      packet->l3_ofs = (char *)data - l2;
  
      nw_frag = 0;
      if (OVS_LIKELY(dl_type == htons(ETH_TYPE_IP))) {
          const struct ip_header *nh = data;
          int ip_len;
  
          if (OVS_UNLIKELY(size < IP_HEADER_LEN)) {
              goto out;
          }
          ip_len = IP_IHL(nh->ip_ihl_ver) * 4;
  
          if (OVS_UNLIKELY(ip_len < IP_HEADER_LEN)) {
              goto out;
          }
  
          /* Push both source and destination address at once. */
          miniflow_push_words(mf, nw_src, &nh->ip_src, 2);
  
          nw_tos = nh->ip_tos;
          nw_ttl = nh->ip_ttl;
          nw_proto = nh->ip_proto;
          if (OVS_UNLIKELY(IP_IS_FRAGMENT(nh->ip_frag_off))) {
              nw_frag = FLOW_NW_FRAG_ANY;
              if (nh->ip_frag_off & htons(IP_FRAG_OFF_MASK)) {
                  nw_frag |= FLOW_NW_FRAG_LATER;
              }
          }
          if (OVS_UNLIKELY(size < ip_len)) {
              goto out;
          }
          data_pull(&data, &size, ip_len);
  
      } else if (dl_type == htons(ETH_TYPE_IPV6)) {
          const struct ovs_16aligned_ip6_hdr *nh;
          ovs_be32 tc_flow;
  
          if (OVS_UNLIKELY(size < sizeof *nh)) {
              goto out;
          }
          nh = data_pull(&data, &size, sizeof *nh);
  
          miniflow_push_words(mf, ipv6_src, &nh->ip6_src,
                              sizeof nh->ip6_src / 4);
          miniflow_push_words(mf, ipv6_dst, &nh->ip6_dst,
                              sizeof nh->ip6_dst / 4);
  
          tc_flow = get_16aligned_be32(&nh->ip6_flow);
          {
              ovs_be32 label = tc_flow & htonl(IPV6_LABEL_MASK);
              miniflow_push_be32_check(mf, ipv6_label, label);
          }
  
          nw_tos = ntohl(tc_flow) >> 20;
          nw_ttl = nh->ip6_hlim;
          nw_proto = nh->ip6_nxt;
  
          while (1) {
              if (OVS_LIKELY((nw_proto != IPPROTO_HOPOPTS)
                             && (nw_proto != IPPROTO_ROUTING)
                             && (nw_proto != IPPROTO_DSTOPTS)
                             && (nw_proto != IPPROTO_AH)
                             && (nw_proto != IPPROTO_FRAGMENT))) {
                  /* It's either a terminal header (e.g., TCP, UDP) or one we
                   * don't understand.  In either case, we're done with the
                   * packet, so use it to fill in 'nw_proto'. */
                  break;
              }
  
              /* We only verify that at least 8 bytes of the next header are
               * available, but many of these headers are longer.  Ensure that
               * accesses within the extension header are within those first 8
               * bytes. All extension headers are required to be at least 8
               * bytes. */
              if (OVS_UNLIKELY(size < 8)) {
                  goto out;
              }
  
              if ((nw_proto == IPPROTO_HOPOPTS)
                  || (nw_proto == IPPROTO_ROUTING)
                  || (nw_proto == IPPROTO_DSTOPTS)) {
                  /* These headers, while different, have the fields we care
                   * about in the same location and with the same
                   * interpretation. */
                  const struct ip6_ext *ext_hdr = data;
                  nw_proto = ext_hdr->ip6e_nxt;
                  if (OVS_UNLIKELY(!data_try_pull(&data, &size,
                                                  (ext_hdr->ip6e_len + 1) * 8))) {
                      goto out;
                  }
              } else if (nw_proto == IPPROTO_AH) {
                  /* A standard AH definition isn't available, but the fields
                   * we care about are in the same location as the generic
                   * option header--only the header length is calculated
                   * differently. */
                  const struct ip6_ext *ext_hdr = data;
                  nw_proto = ext_hdr->ip6e_nxt;
                  if (OVS_UNLIKELY(!data_try_pull(&data, &size,
                                                  (ext_hdr->ip6e_len + 2) * 4))) {
                      goto out;
                  }
              } else if (nw_proto == IPPROTO_FRAGMENT) {
                  const struct ovs_16aligned_ip6_frag *frag_hdr = data;
  
                  nw_proto = frag_hdr->ip6f_nxt;
                  if (!data_try_pull(&data, &size, sizeof *frag_hdr)) {
                      goto out;
                  }
  
                  /* We only process the first fragment. */
                  if (frag_hdr->ip6f_offlg != htons(0)) {
                      nw_frag = FLOW_NW_FRAG_ANY;
                      if ((frag_hdr->ip6f_offlg & IP6F_OFF_MASK) != htons(0)) {
                          nw_frag |= FLOW_NW_FRAG_LATER;
                          nw_proto = IPPROTO_FRAGMENT;
                          break;
                      }
                  }
              }
          }
      } else {
          if (dl_type == htons(ETH_TYPE_ARP) ||
              dl_type == htons(ETH_TYPE_RARP)) {
              uint8_t arp_buf[2][ETH_ADDR_LEN];
              const struct arp_eth_header *arp = (const struct arp_eth_header *)
                  data_try_pull(&data, &size, ARP_ETH_HEADER_LEN);
  
              if (OVS_LIKELY(arp) && OVS_LIKELY(arp->ar_hrd == htons(1))
                  && OVS_LIKELY(arp->ar_pro == htons(ETH_TYPE_IP))
                  && OVS_LIKELY(arp->ar_hln == ETH_ADDR_LEN)
                  && OVS_LIKELY(arp->ar_pln == 4)) {
                  miniflow_push_words(mf, nw_src, &arp->ar_spa, 1);
                  miniflow_push_words(mf, nw_dst, &arp->ar_tpa, 1);
  
                  /* We only match on the lower 8 bits of the opcode. */
                  if (OVS_LIKELY(ntohs(arp->ar_op) <= 0xff)) {
                      miniflow_push_be32(mf, nw_frag, htonl(ntohs(arp->ar_op)));
                  }
  
                  /* Must be adjacent. */
                  BUILD_ASSERT(offsetof(struct flow, arp_sha) + 6
                               == offsetof(struct flow, arp_tha));
  
                  memcpy(arp_buf[0], arp->ar_sha, ETH_ADDR_LEN);
                  memcpy(arp_buf[1], arp->ar_tha, ETH_ADDR_LEN);
                  miniflow_push_words(mf, arp_sha, arp_buf,
                                      ETH_ADDR_LEN * 2 / 4);
              }
          }
          goto out;
      }
  
      packet->l4_ofs = (char *)data - l2;
      miniflow_push_be32(mf, nw_frag,
                         BYTES_TO_BE32(nw_frag, nw_tos, nw_ttl, nw_proto));
  
      if (OVS_LIKELY(!(nw_frag & FLOW_NW_FRAG_LATER))) {
          if (OVS_LIKELY(nw_proto == IPPROTO_TCP)) {
              if (OVS_LIKELY(size >= TCP_HEADER_LEN)) {
                  const struct tcp_header *tcp = data;
  
                  miniflow_push_be32(mf, tcp_flags,
                                     TCP_FLAGS_BE32(tcp->tcp_ctl));
                  miniflow_push_words(mf, tp_src, &tcp->tcp_src, 1);
              }
          } else if (OVS_LIKELY(nw_proto == IPPROTO_UDP)) {
              if (OVS_LIKELY(size >= UDP_HEADER_LEN)) {
                  const struct udp_header *udp = data;
  
                  miniflow_push_words(mf, tp_src, &udp->udp_src, 1);
              }
          } else if (OVS_LIKELY(nw_proto == IPPROTO_SCTP)) {
              if (OVS_LIKELY(size >= SCTP_HEADER_LEN)) {
                  const struct sctp_header *sctp = data;
  
                  miniflow_push_words(mf, tp_src, &sctp->sctp_src, 1);
              }
          } else if (OVS_LIKELY(nw_proto == IPPROTO_ICMP)) {
              if (OVS_LIKELY(size >= ICMP_HEADER_LEN)) {
                  const struct icmp_header *icmp = data;
  
                  miniflow_push_be16(mf, tp_src, htons(icmp->icmp_type));
                  miniflow_push_be16(mf, tp_dst, htons(icmp->icmp_code));
              }
          } else if (OVS_LIKELY(nw_proto == IPPROTO_IGMP)) {
              if (OVS_LIKELY(size >= IGMP_HEADER_LEN)) {
                  const struct igmp_header *igmp = data;
  
                  miniflow_push_be16(mf, tp_src, htons(igmp->igmp_type));
                  miniflow_push_be16(mf, tp_dst, htons(igmp->igmp_code));
                  miniflow_push_be32(mf, igmp_group_ip4,
                                     get_16aligned_be32(&igmp->group));
              }
          } else if (OVS_LIKELY(nw_proto == IPPROTO_ICMPV6)) {
              if (OVS_LIKELY(size >= sizeof(struct icmp6_hdr))) {
                  const struct in6_addr *nd_target = NULL;
                  uint8_t arp_buf[2][ETH_ADDR_LEN];
                  const struct icmp6_hdr *icmp = data_pull(&data, &size,
                                                           sizeof *icmp);
                  memset(arp_buf, 0, sizeof arp_buf);
                  if (OVS_LIKELY(parse_icmpv6(&data, &size, icmp, &nd_target,
                                              arp_buf))) {
                      miniflow_push_words(mf, arp_sha, arp_buf,
                                               ETH_ADDR_LEN * 2 / 4);
                      if (nd_target) {
                          miniflow_push_words(mf, nd_target, nd_target,
                                              sizeof *nd_target / 4);
                      }
                      miniflow_push_be16(mf, tp_src, htons(icmp->icmp6_type));
                      miniflow_push_be16(mf, tp_dst, htons(icmp->icmp6_code));
                  }
              }
          }
      }
      if (md) {
          miniflow_push_uint32_check(mf, dp_hash, md->dp_hash);
      }
   out:
      dst->map = mf.map;
  }
  
  /* For every bit of a field that is wildcarded in 'wildcards', sets the
   * corresponding bit in 'flow' to zero. */
  void
  flow_zero_wildcards(struct flow *flow, const struct flow_wildcards *wildcards)
  {
      uint32_t *flow_u32 = (uint32_t *) flow;
      const uint32_t *wc_u32 = (const uint32_t *) &wildcards->masks;
      size_t i;
  
      for (i = 0; i < FLOW_U32S; i++) {
          flow_u32[i] &= wc_u32[i];
      }
  }
  
  void
  flow_unwildcard_tp_ports(const struct flow *flow, struct flow_wildcards *wc)
  {
      if (flow->nw_proto != IPPROTO_ICMP) {
          memset(&wc->masks.tp_src, 0xff, sizeof wc->masks.tp_src);
          memset(&wc->masks.tp_dst, 0xff, sizeof wc->masks.tp_dst);
      } else {
          wc->masks.tp_src = htons(0xff);
          wc->masks.tp_dst = htons(0xff);
      }
  }
  
  /* Initializes 'fmd' with the metadata found in 'flow'. */
  void
  flow_get_metadata(const struct flow *flow, struct flow_metadata *fmd)
  {
      BUILD_ASSERT_DECL(FLOW_WC_SEQ == 28);
  
      fmd->dp_hash = flow->dp_hash;
      fmd->recirc_id = flow->recirc_id;
      fmd->tun_id = flow->tunnel.tun_id;
      fmd->tun_src = flow->tunnel.ip_src;
      fmd->tun_dst = flow->tunnel.ip_dst;
      fmd->metadata = flow->metadata;
      memcpy(fmd->regs, flow->regs, sizeof fmd->regs);
      fmd->pkt_mark = flow->pkt_mark;
      fmd->in_port = flow->in_port.ofp_port;
  }
  
  char *
  flow_to_string(const struct flow *flow)
  {
      struct ds ds = DS_EMPTY_INITIALIZER;
      flow_format(&ds, flow);
      return ds_cstr(&ds);
  }
  
  const char *
  flow_tun_flag_to_string(uint32_t flags)
  {
      switch (flags) {
      case FLOW_TNL_F_DONT_FRAGMENT:
          return "df";
      case FLOW_TNL_F_CSUM:
          return "csum";
      case FLOW_TNL_F_KEY:
          return "key";
      case FLOW_TNL_F_OAM:
          return "oam";
      default:
          return NULL;
      }
  }
  
  void
  format_flags(struct ds *ds, const char *(*bit_to_string)(uint32_t),
               uint32_t flags, char del)
  {
      uint32_t bad = 0;
  
      if (!flags) {
          return;
      }
      while (flags) {
          uint32_t bit = rightmost_1bit(flags);
          const char *s;
  
          s = bit_to_string(bit);
          if (s) {
              ds_put_format(ds, "%s%c", s, del);
          } else {
              bad |= bit;
          }
  
          flags &= ~bit;
      }
  
      if (bad) {
          ds_put_format(ds, "0x%"PRIx32"%c", bad, del);
      }
      ds_chomp(ds, del);
  }
  
  void
  format_flags_masked(struct ds *ds, const char *name,
                      const char *(*bit_to_string)(uint32_t), uint32_t flags,
                      uint32_t mask)
  {
      if (name) {
          ds_put_format(ds, "%s=", name);
      }
      while (mask) {
          uint32_t bit = rightmost_1bit(mask);
          const char *s = bit_to_string(bit);
  
          ds_put_format(ds, "%s%s", (flags & bit) ? "+" : "-",
                        s ? s : "[Unknown]");
          mask &= ~bit;
      }
  }
  
  void
  flow_format(struct ds *ds, const struct flow *flow)
  {
      struct match match;
      struct flow_wildcards *wc = &match.wc;
  
      match_wc_init(&match, flow);
  
      /* As this function is most often used for formatting a packet in a
       * packet-in message, skip formatting the packet context fields that are
       * all-zeroes (Openflow spec encourages leaving out all-zeroes context
       * fields from the packet-in messages).  We make an exception with the
       * 'in_port' field, which we always format, as packets usually have an
       * in_port, and 0 is a port just like any other port. */
      if (!flow->skb_priority) {
          WC_UNMASK_FIELD(wc, skb_priority);
      }
      if (!flow->pkt_mark) {
          WC_UNMASK_FIELD(wc, pkt_mark);
      }
      if (!flow->recirc_id) {
          WC_UNMASK_FIELD(wc, recirc_id);
      }
      for (int i = 0; i < FLOW_N_REGS; i++) {
          if (!flow->regs[i]) {
              WC_UNMASK_FIELD(wc, regs[i]);
          }
      }
      if (!flow->metadata) {
          WC_UNMASK_FIELD(wc, metadata);
      }
  
      match_format(&match, ds, OFP_DEFAULT_PRIORITY);
  }
  
  void
  flow_print(FILE *stream, const struct flow *flow)
  {
      char *s = flow_to_string(flow);
      fputs(s, stream);
      free(s);
  }
  
  /* flow_wildcards functions. */
  
  /* Initializes 'wc' as a set of wildcards that matches every packet. */
  void
  flow_wildcards_init_catchall(struct flow_wildcards *wc)
  {
      memset(&wc->masks, 0, sizeof wc->masks);
  }
  
  /* Converts a flow into flow wildcards.  It sets the wildcard masks based on
   * the packet headers extracted to 'flow'.  It will not set the mask for fields
   * that do not make sense for the packet type.  OpenFlow-only metadata is
   * wildcarded, but other metadata is unconditionally exact-matched. */
  void flow_wildcards_init_for_packet(struct flow_wildcards *wc,
                                      const struct flow *flow)
  {
      memset(&wc->masks, 0x0, sizeof wc->masks);
  
      /* Update this function whenever struct flow changes. */
      BUILD_ASSERT_DECL(FLOW_WC_SEQ == 28);
  
      if (flow->tunnel.ip_dst) {
          if (flow->tunnel.flags & FLOW_TNL_F_KEY) {
              WC_MASK_FIELD(wc, tunnel.tun_id);
          }
          WC_MASK_FIELD(wc, tunnel.ip_src);
          WC_MASK_FIELD(wc, tunnel.ip_dst);
          WC_MASK_FIELD(wc, tunnel.flags);
          WC_MASK_FIELD(wc, tunnel.ip_tos);
          WC_MASK_FIELD(wc, tunnel.ip_ttl);
          WC_MASK_FIELD(wc, tunnel.tp_src);
          WC_MASK_FIELD(wc, tunnel.tp_dst);
      } else if (flow->tunnel.tun_id) {
          WC_MASK_FIELD(wc, tunnel.tun_id);
      }
  
      /* metadata and regs wildcarded. */
  
      WC_MASK_FIELD(wc, skb_priority);
      WC_MASK_FIELD(wc, pkt_mark);
      WC_MASK_FIELD(wc, recirc_id);
      WC_MASK_FIELD(wc, dp_hash);
      WC_MASK_FIELD(wc, in_port);
  
      /* actset_output wildcarded. */
  
      WC_MASK_FIELD(wc, dl_dst);
      WC_MASK_FIELD(wc, dl_src);
      WC_MASK_FIELD(wc, dl_type);
      WC_MASK_FIELD(wc, vlan_tci);
  
      if (flow->dl_type == htons(ETH_TYPE_IP)) {
          WC_MASK_FIELD(wc, nw_src);
          WC_MASK_FIELD(wc, nw_dst);
      } else if (flow->dl_type == htons(ETH_TYPE_IPV6)) {
          WC_MASK_FIELD(wc, ipv6_src);
          WC_MASK_FIELD(wc, ipv6_dst);
          WC_MASK_FIELD(wc, ipv6_label);
      } else if (flow->dl_type == htons(ETH_TYPE_ARP) ||
                 flow->dl_type == htons(ETH_TYPE_RARP)) {
          WC_MASK_FIELD(wc, nw_src);
          WC_MASK_FIELD(wc, nw_dst);
          WC_MASK_FIELD(wc, nw_proto);
          WC_MASK_FIELD(wc, arp_sha);
          WC_MASK_FIELD(wc, arp_tha);
          return;
      } else if (eth_type_mpls(flow->dl_type)) {
          for (int i = 0; i < FLOW_MAX_MPLS_LABELS; i++) {
              WC_MASK_FIELD(wc, mpls_lse[i]);
              if (flow->mpls_lse[i] & htonl(MPLS_BOS_MASK)) {
                  break;
              }
          }
          return;
      } else {
          return; /* Unknown ethertype. */
      }
  
      /* IPv4 or IPv6. */
      WC_MASK_FIELD(wc, nw_frag);
      WC_MASK_FIELD(wc, nw_tos);
      WC_MASK_FIELD(wc, nw_ttl);
      WC_MASK_FIELD(wc, nw_proto);
  
      /* No transport layer header in later fragments. */
      if (!(flow->nw_frag & FLOW_NW_FRAG_LATER) &&
          (flow->nw_proto == IPPROTO_ICMP ||
           flow->nw_proto == IPPROTO_ICMPV6 ||
           flow->nw_proto == IPPROTO_TCP ||
           flow->nw_proto == IPPROTO_UDP ||
           flow->nw_proto == IPPROTO_SCTP ||
           flow->nw_proto == IPPROTO_IGMP)) {
          WC_MASK_FIELD(wc, tp_src);
          WC_MASK_FIELD(wc, tp_dst);
  
          if (flow->nw_proto == IPPROTO_TCP) {
              WC_MASK_FIELD(wc, tcp_flags);
          } else if (flow->nw_proto == IPPROTO_ICMPV6) {
              WC_MASK_FIELD(wc, arp_sha);
              WC_MASK_FIELD(wc, arp_tha);
              WC_MASK_FIELD(wc, nd_target);
          } else if (flow->nw_proto == IPPROTO_IGMP) {
              WC_MASK_FIELD(wc, igmp_group_ip4);
          }
      }
  }
  
  /* Return a map of possible fields for a packet of the same type as 'flow'.
   * Including extra bits in the returned mask is not wrong, it is just less
   * optimal.
   *
   * This is a less precise version of flow_wildcards_init_for_packet() above. */
  uint64_t
  flow_wc_map(const struct flow *flow)
  {
      /* Update this function whenever struct flow changes. */
      BUILD_ASSERT_DECL(FLOW_WC_SEQ == 28);
  
      uint64_t map = (flow->tunnel.ip_dst) ? MINIFLOW_MAP(tunnel) : 0;
  
      /* Metadata fields that can appear on packet input. */
      map |= MINIFLOW_MAP(skb_priority) | MINIFLOW_MAP(pkt_mark)
          | MINIFLOW_MAP(recirc_id) | MINIFLOW_MAP(dp_hash)
          | MINIFLOW_MAP(in_port)
          | MINIFLOW_MAP(dl_dst) | MINIFLOW_MAP(dl_src)
          | MINIFLOW_MAP(dl_type) | MINIFLOW_MAP(vlan_tci);
  
      /* Ethertype-dependent fields. */
      if (OVS_LIKELY(flow->dl_type == htons(ETH_TYPE_IP))) {
          map |= MINIFLOW_MAP(nw_src) | MINIFLOW_MAP(nw_dst)
              | MINIFLOW_MAP(nw_proto) | MINIFLOW_MAP(nw_frag)
              | MINIFLOW_MAP(nw_tos) | MINIFLOW_MAP(nw_ttl);
          if (OVS_UNLIKELY(flow->nw_proto == IPPROTO_IGMP)) {
              map |= MINIFLOW_MAP(igmp_group_ip4);
          } else {
              map |= MINIFLOW_MAP(tcp_flags)
                  | MINIFLOW_MAP(tp_src) | MINIFLOW_MAP(tp_dst);
          }
      } else if (flow->dl_type == htons(ETH_TYPE_IPV6)) {
          map |= MINIFLOW_MAP(ipv6_src) | MINIFLOW_MAP(ipv6_dst)
              | MINIFLOW_MAP(ipv6_label)
              | MINIFLOW_MAP(nw_proto) | MINIFLOW_MAP(nw_frag)
              | MINIFLOW_MAP(nw_tos) | MINIFLOW_MAP(nw_ttl);
          if (OVS_UNLIKELY(flow->nw_proto == IPPROTO_ICMPV6)) {
              map |= MINIFLOW_MAP(nd_target)
                  | MINIFLOW_MAP(arp_sha) | MINIFLOW_MAP(arp_tha);
          } else {
              map |= MINIFLOW_MAP(tcp_flags)
                  | MINIFLOW_MAP(tp_src) | MINIFLOW_MAP(tp_dst);
          }
      } else if (eth_type_mpls(flow->dl_type)) {
          map |= MINIFLOW_MAP(mpls_lse);
      } else if (flow->dl_type == htons(ETH_TYPE_ARP) ||
                 flow->dl_type == htons(ETH_TYPE_RARP)) {
          map |= MINIFLOW_MAP(nw_src) | MINIFLOW_MAP(nw_dst)
              | MINIFLOW_MAP(nw_proto)
              | MINIFLOW_MAP(arp_sha) | MINIFLOW_MAP(arp_tha);
      }
  
      return map;
  }
  
  /* Clear the metadata and register wildcard masks. They are not packet
   * header fields. */
  void
  flow_wildcards_clear_non_packet_fields(struct flow_wildcards *wc)
  {
      /* Update this function whenever struct flow changes. */
      BUILD_ASSERT_DECL(FLOW_WC_SEQ == 28);
  
      memset(&wc->masks.metadata, 0, sizeof wc->masks.metadata);
      memset(&wc->masks.regs, 0, sizeof wc->masks.regs);
      wc->masks.actset_output = 0;
  }
  
  /* Returns true if 'wc' matches every packet, false if 'wc' fixes any bits or
   * fields. */
  bool
  flow_wildcards_is_catchall(const struct flow_wildcards *wc)
  {
      const uint32_t *wc_u32 = (const uint32_t *) &wc->masks;
      size_t i;
  
      for (i = 0; i < FLOW_U32S; i++) {
          if (wc_u32[i]) {
              return false;
          }
      }
      return true;
  }
  
  /* Sets 'dst' as the bitwise AND of wildcards in 'src1' and 'src2'.
   * That is, a bit or a field is wildcarded in 'dst' if it is wildcarded
   * in 'src1' or 'src2' or both.  */
  void
  flow_wildcards_and(struct flow_wildcards *dst,
                     const struct flow_wildcards *src1,
                     const struct flow_wildcards *src2)
  {
      uint32_t *dst_u32 = (uint32_t *) &dst->masks;
      const uint32_t *src1_u32 = (const uint32_t *) &src1->masks;
      const uint32_t *src2_u32 = (const uint32_t *) &src2->masks;
      size_t i;
  
      for (i = 0; i < FLOW_U32S; i++) {
          dst_u32[i] = src1_u32[i] & src2_u32[i];
      }
  }
  
  /* Sets 'dst' as the bitwise OR of wildcards in 'src1' and 'src2'.  That
   * is, a bit or a field is wildcarded in 'dst' if it is neither
   * wildcarded in 'src1' nor 'src2'. */
  void
  flow_wildcards_or(struct flow_wildcards *dst,
                    const struct flow_wildcards *src1,
                    const struct flow_wildcards *src2)
  {
      uint32_t *dst_u32 = (uint32_t *) &dst->masks;
      const uint32_t *src1_u32 = (const uint32_t *) &src1->masks;
      const uint32_t *src2_u32 = (const uint32_t *) &src2->masks;
      size_t i;
  
      for (i = 0; i < FLOW_U32S; i++) {
          dst_u32[i] = src1_u32[i] | src2_u32[i];
      }
  }
  
  /* Returns a hash of the wildcards in 'wc'. */
  uint32_t
  flow_wildcards_hash(const struct flow_wildcards *wc, uint32_t basis)
  {
      return flow_hash(&wc->masks, basis);
  }
  
  /* Returns true if 'a' and 'b' represent the same wildcards, false if they are
   * different. */
  bool
  flow_wildcards_equal(const struct flow_wildcards *a,
                       const struct flow_wildcards *b)
  {
      return flow_equal(&a->masks, &b->masks);
  }
  
  /* Returns true if at least one bit or field is wildcarded in 'a' but not in
   * 'b', false otherwise. */
  bool
  flow_wildcards_has_extra(const struct flow_wildcards *a,
                           const struct flow_wildcards *b)
  {
      const uint32_t *a_u32 = (const uint32_t *) &a->masks;
      const uint32_t *b_u32 = (const uint32_t *) &b->masks;
      size_t i;
  
      for (i = 0; i < FLOW_U32S; i++) {
          if ((a_u32[i] & b_u32[i]) != b_u32[i]) {
              return true;
          }
      }
      return false;
  }
  
  /* Returns true if 'a' and 'b' are equal, except that 0-bits (wildcarded bits)
   * in 'wc' do not need to be equal in 'a' and 'b'. */
  bool
  flow_equal_except(const struct flow *a, const struct flow *b,
                    const struct flow_wildcards *wc)
  {
      const uint32_t *a_u32 = (const uint32_t *) a;
      const uint32_t *b_u32 = (const uint32_t *) b;
      const uint32_t *wc_u32 = (const uint32_t *) &wc->masks;
      size_t i;
  
      for (i = 0; i < FLOW_U32S; i++) {
          if ((a_u32[i] ^ b_u32[i]) & wc_u32[i]) {
              return false;
          }
      }
      return true;
  }
  
  /* Sets the wildcard mask for register 'idx' in 'wc' to 'mask'.
   * (A 0-bit indicates a wildcard bit.) */
  void
  flow_wildcards_set_reg_mask(struct flow_wildcards *wc, int idx, uint32_t mask)
  {
      wc->masks.regs[idx] = mask;
  }
  
  /* Sets the wildcard mask for register 'idx' in 'wc' to 'mask'.
   * (A 0-bit indicates a wildcard bit.) */
  void
  flow_wildcards_set_xreg_mask(struct flow_wildcards *wc, int idx, uint64_t mask)
  {
      flow_set_xreg(&wc->masks, idx, mask);
  }
  
  /* Calculates the 5-tuple hash from the given miniflow.
   * This returns the same value as flow_hash_5tuple for the corresponding
   * flow. */
  uint32_t
  miniflow_hash_5tuple(const struct miniflow *flow, uint32_t basis)
  {
      uint32_t hash = basis;
  
      if (flow) {
          ovs_be16 dl_type = MINIFLOW_GET_BE16(flow, dl_type);
  
          hash = hash_add(hash, MINIFLOW_GET_U8(flow, nw_proto));
  
          /* Separate loops for better optimization. */
          if (dl_type == htons(ETH_TYPE_IPV6)) {
              uint64_t map = MINIFLOW_MAP(ipv6_src) | MINIFLOW_MAP(ipv6_dst)
                  | MINIFLOW_MAP(tp_src); /* Covers both ports */
              uint32_t value;
  
              MINIFLOW_FOR_EACH_IN_MAP(value, flow, map) {
                  hash = hash_add(hash, value);
              }
          } else {
              uint64_t map = MINIFLOW_MAP(nw_src) | MINIFLOW_MAP(nw_dst)
                  | MINIFLOW_MAP(tp_src); /* Covers both ports */
              uint32_t value;
  
              MINIFLOW_FOR_EACH_IN_MAP(value, flow, map) {
                  hash = hash_add(hash, value);
              }
          }
          hash = hash_finish(hash, 42); /* Arbitrary number. */
      }
      return hash;
  }
  
  BUILD_ASSERT_DECL(offsetof(struct flow, tp_src) + 2
                    == offsetof(struct flow, tp_dst) &&
                    offsetof(struct flow, tp_src) / 4
                    == offsetof(struct flow, tp_dst) / 4);
  BUILD_ASSERT_DECL(offsetof(struct flow, ipv6_src) + 16
                    == offsetof(struct flow, ipv6_dst));
  
  /* Calculates the 5-tuple hash from the given flow. */
  uint32_t
  flow_hash_5tuple(const struct flow *flow, uint32_t basis)
  {
      uint32_t hash = basis;
  
      if (flow) {
          const uint32_t *flow_u32 = (const uint32_t *)flow;
  
          hash = hash_add(hash, flow->nw_proto);
  
          if (flow->dl_type == htons(ETH_TYPE_IPV6)) {
              int ofs = offsetof(struct flow, ipv6_src) / 4;
              int end = ofs + 2 * sizeof flow->ipv6_src / 4;
  
              while (ofs < end) {
                  hash = hash_add(hash, flow_u32[ofs++]);
              }
          } else {
              hash = hash_add(hash, (OVS_FORCE uint32_t) flow->nw_src);
              hash = hash_add(hash, (OVS_FORCE uint32_t) flow->nw_dst);
          }
          hash = hash_add(hash, flow_u32[offsetof(struct flow, tp_src) / 4]);
  
          hash = hash_finish(hash, 42); /* Arbitrary number. */
      }
      return hash;
  }
  
  /* Hashes 'flow' based on its L2 through L4 protocol information. */
  uint32_t
  flow_hash_symmetric_l4(const struct flow *flow, uint32_t basis)
  {
      struct {
          union {
              ovs_be32 ipv4_addr;
              struct in6_addr ipv6_addr;
          };
          ovs_be16 eth_type;
          ovs_be16 vlan_tci;
          ovs_be16 tp_port;
          uint8_t eth_addr[ETH_ADDR_LEN];
          uint8_t ip_proto;
      } fields;
  
      int i;
  
      memset(&fields, 0, sizeof fields);
      for (i = 0; i < ETH_ADDR_LEN; i++) {
          fields.eth_addr[i] = flow->dl_src[i] ^ flow->dl_dst[i];
      }
      fields.vlan_tci = flow->vlan_tci & htons(VLAN_VID_MASK);
      fields.eth_type = flow->dl_type;
  
      /* UDP source and destination port are not taken into account because they
       * will not necessarily be symmetric in a bidirectional flow. */
      if (fields.eth_type == htons(ETH_TYPE_IP)) {
          fields.ipv4_addr = flow->nw_src ^ flow->nw_dst;
          fields.ip_proto = flow->nw_proto;
          if (fields.ip_proto == IPPROTO_TCP || fields.ip_proto == IPPROTO_SCTP) {
              fields.tp_port = flow->tp_src ^ flow->tp_dst;
          }
      } else if (fields.eth_type == htons(ETH_TYPE_IPV6)) {
          const uint8_t *a = &flow->ipv6_src.s6_addr[0];
          const uint8_t *b = &flow->ipv6_dst.s6_addr[0];
          uint8_t *ipv6_addr = &fields.ipv6_addr.s6_addr[0];
  
          for (i=0; i<16; i++) {
              ipv6_addr[i] = a[i] ^ b[i];
          }
          fields.ip_proto = flow->nw_proto;
          if (fields.ip_proto == IPPROTO_TCP || fields.ip_proto == IPPROTO_SCTP) {
              fields.tp_port = flow->tp_src ^ flow->tp_dst;
          }
      }
      return jhash_bytes(&fields, sizeof fields, basis);
  }
  
  /* Initialize a flow with random fields that matter for nx_hash_fields. */
  void
  flow_random_hash_fields(struct flow *flow)
  {
      uint16_t rnd = random_uint16();
  
      /* Initialize to all zeros. */
      memset(flow, 0, sizeof *flow);
  
      eth_addr_random(flow->dl_src);
      eth_addr_random(flow->dl_dst);
  
      flow->vlan_tci = (OVS_FORCE ovs_be16) (random_uint16() & VLAN_VID_MASK);
  
      /* Make most of the random flows IPv4, some IPv6, and rest random. */
      flow->dl_type = rnd < 0x8000 ? htons(ETH_TYPE_IP) :
          rnd < 0xc000 ? htons(ETH_TYPE_IPV6) : (OVS_FORCE ovs_be16)rnd;
  
      if (dl_type_is_ip_any(flow->dl_type)) {
          if (flow->dl_type == htons(ETH_TYPE_IP)) {
              flow->nw_src = (OVS_FORCE ovs_be32)random_uint32();
              flow->nw_dst = (OVS_FORCE ovs_be32)random_uint32();
          } else {
              random_bytes(&flow->ipv6_src, sizeof flow->ipv6_src);
              random_bytes(&flow->ipv6_dst, sizeof flow->ipv6_dst);
          }
          /* Make most of IP flows TCP, some UDP or SCTP, and rest random. */
          rnd = random_uint16();
          flow->nw_proto = rnd < 0x8000 ? IPPROTO_TCP :
              rnd < 0xc000 ? IPPROTO_UDP :
              rnd < 0xd000 ? IPPROTO_SCTP : (uint8_t)rnd;
          if (flow->nw_proto == IPPROTO_TCP ||
              flow->nw_proto == IPPROTO_UDP ||
              flow->nw_proto == IPPROTO_SCTP) {
              flow->tp_src = (OVS_FORCE ovs_be16)random_uint16();
              flow->tp_dst = (OVS_FORCE ovs_be16)random_uint16();
          }
      }
  }
  
  /* Masks the fields in 'wc' that are used by the flow hash 'fields'. */
  void
  flow_mask_hash_fields(const struct flow *flow, struct flow_wildcards *wc,
                        enum nx_hash_fields fields)
  {
      switch (fields) {
      case NX_HASH_FIELDS_ETH_SRC:
          memset(&wc->masks.dl_src, 0xff, sizeof wc->masks.dl_src);
          break;
  
      case NX_HASH_FIELDS_SYMMETRIC_L4:
          memset(&wc->masks.dl_src, 0xff, sizeof wc->masks.dl_src);
          memset(&wc->masks.dl_dst, 0xff, sizeof wc->masks.dl_dst);
          if (flow->dl_type == htons(ETH_TYPE_IP)) {
              memset(&wc->masks.nw_src, 0xff, sizeof wc->masks.nw_src);
              memset(&wc->masks.nw_dst, 0xff, sizeof wc->masks.nw_dst);
          } else if (flow->dl_type == htons(ETH_TYPE_IPV6)) {
              memset(&wc->masks.ipv6_src, 0xff, sizeof wc->masks.ipv6_src);
              memset(&wc->masks.ipv6_dst, 0xff, sizeof wc->masks.ipv6_dst);
          }
          if (is_ip_any(flow)) {
              memset(&wc->masks.nw_proto, 0xff, sizeof wc->masks.nw_proto);
              flow_unwildcard_tp_ports(flow, wc);
          }
          wc->masks.vlan_tci |= htons(VLAN_VID_MASK | VLAN_CFI);
          break;
  
      default:
          OVS_NOT_REACHED();
      }
  }
  
  /* Hashes the portions of 'flow' designated by 'fields'. */
  uint32_t
  flow_hash_fields(const struct flow *flow, enum nx_hash_fields fields,
                   uint16_t basis)
  {
      switch (fields) {
  
      case NX_HASH_FIELDS_ETH_SRC:
          return jhash_bytes(flow->dl_src, sizeof flow->dl_src, basis);
  
      case NX_HASH_FIELDS_SYMMETRIC_L4:
          return flow_hash_symmetric_l4(flow, basis);
      }
  
      OVS_NOT_REACHED();
  }
  
  /* Returns a string representation of 'fields'. */
  const char *
  flow_hash_fields_to_str(enum nx_hash_fields fields)
  {
      switch (fields) {
      case NX_HASH_FIELDS_ETH_SRC: return "eth_src";
      case NX_HASH_FIELDS_SYMMETRIC_L4: return "symmetric_l4";
      default: return "<unknown>";
      }
  }
  
  /* Returns true if the value of 'fields' is supported. Otherwise false. */
  bool
  flow_hash_fields_valid(enum nx_hash_fields fields)
  {
      return fields == NX_HASH_FIELDS_ETH_SRC
          || fields == NX_HASH_FIELDS_SYMMETRIC_L4;
  }
  
  /* Returns a hash value for the bits of 'flow' that are active based on
   * 'wc', given 'basis'. */
  uint32_t
  flow_hash_in_wildcards(const struct flow *flow,
                         const struct flow_wildcards *wc, uint32_t basis)
  {
      const uint32_t *wc_u32 = (const uint32_t *) &wc->masks;
      const uint32_t *flow_u32 = (const uint32_t *) flow;
      uint32_t hash;
      size_t i;
  
      hash = basis;
      for (i = 0; i < FLOW_U32S; i++) {
          hash = hash_add(hash, flow_u32[i] & wc_u32[i]);
      }
      return hash_finish(hash, 4 * FLOW_U32S);
  }
  
  /* Sets the VLAN VID that 'flow' matches to 'vid', which is interpreted as an
   * OpenFlow 1.0 "dl_vlan" value:
   *
   *      - If it is in the range 0...4095, 'flow->vlan_tci' is set to match
   *        that VLAN.  Any existing PCP match is unchanged (it becomes 0 if
   *        'flow' previously matched packets without a VLAN header).
   *
   *      - If it is OFP_VLAN_NONE, 'flow->vlan_tci' is set to match a packet
   *        without a VLAN tag.
   *
   *      - Other values of 'vid' should not be used. */
  void
  flow_set_dl_vlan(struct flow *flow, ovs_be16 vid)
  {
      if (vid == htons(OFP10_VLAN_NONE)) {
          flow->vlan_tci = htons(0);
      } else {
          vid &= htons(VLAN_VID_MASK);
          flow->vlan_tci &= ~htons(VLAN_VID_MASK);
          flow->vlan_tci |= htons(VLAN_CFI) | vid;
      }
  }
  
  /* Sets the VLAN VID that 'flow' matches to 'vid', which is interpreted as an
   * OpenFlow 1.2 "vlan_vid" value, that is, the low 13 bits of 'vlan_tci' (VID
   * plus CFI). */
  void
  flow_set_vlan_vid(struct flow *flow, ovs_be16 vid)
  {
      ovs_be16 mask = htons(VLAN_VID_MASK | VLAN_CFI);
      flow->vlan_tci &= ~mask;
      flow->vlan_tci |= vid & mask;
  }
  
  /* Sets the VLAN PCP that 'flow' matches to 'pcp', which should be in the
   * range 0...7.
   *
   * This function has no effect on the VLAN ID that 'flow' matches.
   *
   * After calling this function, 'flow' will not match packets without a VLAN
   * header. */
  void
  flow_set_vlan_pcp(struct flow *flow, uint8_t pcp)
  {
      pcp &= 0x07;
      flow->vlan_tci &= ~htons(VLAN_PCP_MASK);
      flow->vlan_tci |= htons((pcp << VLAN_PCP_SHIFT) | VLAN_CFI);
  }
  
  /* Returns the number of MPLS LSEs present in 'flow'
   *
   * Returns 0 if the 'dl_type' of 'flow' is not an MPLS ethernet type.
   * Otherwise traverses 'flow''s MPLS label stack stopping at the
   * first entry that has the BoS bit set. If no such entry exists then
   * the maximum number of LSEs that can be stored in 'flow' is returned.
   */
  int
  flow_count_mpls_labels(const struct flow *flow, struct flow_wildcards *wc)
  {
      /* dl_type is always masked. */
      if (eth_type_mpls(flow->dl_type)) {
          int i;
          int len = FLOW_MAX_MPLS_LABELS;
  
          for (i = 0; i < len; i++) {
              if (wc) {
                  wc->masks.mpls_lse[i] |= htonl(MPLS_BOS_MASK);
              }
              if (flow->mpls_lse[i] & htonl(MPLS_BOS_MASK)) {
                  return i + 1;
              }
          }
  
          return len;
      } else {
          return 0;
      }
  }
  
  /* Returns the number consecutive of MPLS LSEs, starting at the
   * innermost LSE, that are common in 'a' and 'b'.
   *
   * 'an' must be flow_count_mpls_labels(a).
   * 'bn' must be flow_count_mpls_labels(b).
   */
  int
  flow_count_common_mpls_labels(const struct flow *a, int an,
                                const struct flow *b, int bn,
                                struct flow_wildcards *wc)
  {
      int min_n = MIN(an, bn);
      if (min_n == 0) {
          return 0;
      } else {
          int common_n = 0;
          int a_last = an - 1;
          int b_last = bn - 1;
          int i;
  
          for (i = 0; i < min_n; i++) {
              if (wc) {
                  wc->masks.mpls_lse[a_last - i] = OVS_BE32_MAX;
                  wc->masks.mpls_lse[b_last - i] = OVS_BE32_MAX;
              }
              if (a->mpls_lse[a_last - i] != b->mpls_lse[b_last - i]) {
                  break;
              } else {
                  common_n++;
              }
          }
  
          return common_n;
      }
  }
  
  /* Adds a new outermost MPLS label to 'flow' and changes 'flow''s Ethernet type
   * to 'mpls_eth_type', which must be an MPLS Ethertype.
   *
   * If the new label is the first MPLS label in 'flow', it is generated as;
   *
   *     - label: 2, if 'flow' is IPv6, otherwise 0.
   *
   *     - TTL: IPv4 or IPv6 TTL, if present and nonzero, otherwise 64.
   *
   *     - TC: IPv4 or IPv6 TOS, if present, otherwise 0.
   *
   *     - BoS: 1.
   *
   * If the new label is the second or later label MPLS label in 'flow', it is
   * generated as;
   *
   *     - label: Copied from outer label.
   *
   *     - TTL: Copied from outer label.
   *
   *     - TC: Copied from outer label.
   *
   *     - BoS: 0.
   *
   * 'n' must be flow_count_mpls_labels(flow).  'n' must be less than
   * FLOW_MAX_MPLS_LABELS (because otherwise flow->mpls_lse[] would overflow).
   */
  void
  flow_push_mpls(struct flow *flow, int n, ovs_be16 mpls_eth_type,
                 struct flow_wildcards *wc)
  {
      ovs_assert(eth_type_mpls(mpls_eth_type));
      ovs_assert(n < FLOW_MAX_MPLS_LABELS);
  
      if (n) {
          int i;
  
          if (wc) {
              memset(&wc->masks.mpls_lse, 0xff, sizeof *wc->masks.mpls_lse * n);
          }
          for (i = n; i >= 1; i--) {
              flow->mpls_lse[i] = flow->mpls_lse[i - 1];
          }
          flow->mpls_lse[0] = (flow->mpls_lse[1] & htonl(~MPLS_BOS_MASK));
      } else {
          int label = 0;          /* IPv4 Explicit Null. */
          int tc = 0;
          int ttl = 64;
  
          if (flow->dl_type == htons(ETH_TYPE_IPV6)) {
              label = 2;
          }
  
          if (is_ip_any(flow)) {
              tc = (flow->nw_tos & IP_DSCP_MASK) >> 2;
              if (wc) {
                  wc->masks.nw_tos |= IP_DSCP_MASK;
                  wc->masks.nw_ttl = 0xff;
              }
  
              if (flow->nw_ttl) {
                  ttl = flow->nw_ttl;
              }
          }
  
          flow->mpls_lse[0] = set_mpls_lse_values(ttl, tc, 1, htonl(label));
  
          /* Clear all L3 and L4 fields. */
          BUILD_ASSERT(FLOW_WC_SEQ == 28);
          memset((char *) flow + FLOW_SEGMENT_2_ENDS_AT, 0,
                 sizeof(struct flow) - FLOW_SEGMENT_2_ENDS_AT);
      }
      flow->dl_type = mpls_eth_type;
  }
  
  /* Tries to remove the outermost MPLS label from 'flow'.  Returns true if
   * successful, false otherwise.  On success, sets 'flow''s Ethernet type to
   * 'eth_type'.
   *
   * 'n' must be flow_count_mpls_labels(flow). */
  bool
  flow_pop_mpls(struct flow *flow, int n, ovs_be16 eth_type,
                struct flow_wildcards *wc)
  {
      int i;
  
      if (n == 0) {
          /* Nothing to pop. */
          return false;
      } else if (n == FLOW_MAX_MPLS_LABELS) {
          if (wc) {
              wc->masks.mpls_lse[n - 1] |= htonl(MPLS_BOS_MASK);
          }
          if (!(flow->mpls_lse[n - 1] & htonl(MPLS_BOS_MASK))) {
              /* Can't pop because don't know what to fill in mpls_lse[n - 1]. */
              return false;
          }
      }
  
      if (wc) {
          memset(&wc->masks.mpls_lse[1], 0xff,
                 sizeof *wc->masks.mpls_lse * (n - 1));
      }
      for (i = 1; i < n; i++) {
          flow->mpls_lse[i - 1] = flow->mpls_lse[i];
      }
      flow->mpls_lse[n - 1] = 0;
      flow->dl_type = eth_type;
      return true;
  }
  
  /* Sets the MPLS Label that 'flow' matches to 'label', which is interpreted
   * as an OpenFlow 1.1 "mpls_label" value. */
  void
  flow_set_mpls_label(struct flow *flow, int idx, ovs_be32 label)
  {
      set_mpls_lse_label(&flow->mpls_lse[idx], label);
  }
  
  /* Sets the MPLS TTL that 'flow' matches to 'ttl', which should be in the
   * range 0...255. */
  void
  flow_set_mpls_ttl(struct flow *flow, int idx, uint8_t ttl)
  {
      set_mpls_lse_ttl(&flow->mpls_lse[idx], ttl);
  }
  
  /* Sets the MPLS TC that 'flow' matches to 'tc', which should be in the
   * range 0...7. */
  void
  flow_set_mpls_tc(struct flow *flow, int idx, uint8_t tc)
  {
      set_mpls_lse_tc(&flow->mpls_lse[idx], tc);
  }
  
  /* Sets the MPLS BOS bit that 'flow' matches to which should be 0 or 1. */
  void
  flow_set_mpls_bos(struct flow *flow, int idx, uint8_t bos)
  {
      set_mpls_lse_bos(&flow->mpls_lse[idx], bos);
  }
  
  /* Sets the entire MPLS LSE. */
  void
  flow_set_mpls_lse(struct flow *flow, int idx, ovs_be32 lse)
  {
      flow->mpls_lse[idx] = lse;
  }
  
  static size_t
  flow_compose_l4(struct ofpbuf *b, const struct flow *flow)
  {
      size_t l4_len = 0;
  
      if (!(flow->nw_frag & FLOW_NW_FRAG_ANY)
          || !(flow->nw_frag & FLOW_NW_FRAG_LATER)) {
          if (flow->nw_proto == IPPROTO_TCP) {
              struct tcp_header *tcp;
  
              l4_len = sizeof *tcp;
              tcp = ofpbuf_put_zeros(b, l4_len);
              tcp->tcp_src = flow->tp_src;
              tcp->tcp_dst = flow->tp_dst;
              tcp->tcp_ctl = TCP_CTL(ntohs(flow->tcp_flags), 5);
          } else if (flow->nw_proto == IPPROTO_UDP) {
              struct udp_header *udp;
  
              l4_len = sizeof *udp;
              udp = ofpbuf_put_zeros(b, l4_len);
              udp->udp_src = flow->tp_src;
              udp->udp_dst = flow->tp_dst;
          } else if (flow->nw_proto == IPPROTO_SCTP) {
              struct sctp_header *sctp;
  
              l4_len = sizeof *sctp;
              sctp = ofpbuf_put_zeros(b, l4_len);
              sctp->sctp_src = flow->tp_src;
              sctp->sctp_dst = flow->tp_dst;
          } else if (flow->nw_proto == IPPROTO_ICMP) {
              struct icmp_header *icmp;
  
              l4_len = sizeof *icmp;
              icmp = ofpbuf_put_zeros(b, l4_len);
              icmp->icmp_type = ntohs(flow->tp_src);
              icmp->icmp_code = ntohs(flow->tp_dst);
              icmp->icmp_csum = csum(icmp, ICMP_HEADER_LEN);
          } else if (flow->nw_proto == IPPROTO_IGMP) {
              struct igmp_header *igmp;
  
              l4_len = sizeof *igmp;
              igmp = ofpbuf_put_zeros(b, l4_len);
              igmp->igmp_type = ntohs(flow->tp_src);
              igmp->igmp_code = ntohs(flow->tp_dst);
              put_16aligned_be32(&igmp->group, flow->igmp_group_ip4);
              igmp->igmp_csum = csum(igmp, IGMP_HEADER_LEN);
          } else if (flow->nw_proto == IPPROTO_ICMPV6) {
              struct icmp6_hdr *icmp;
  
              l4_len = sizeof *icmp;
              icmp = ofpbuf_put_zeros(b, l4_len);
              icmp->icmp6_type = ntohs(flow->tp_src);
              icmp->icmp6_code = ntohs(flow->tp_dst);
  
              if (icmp->icmp6_code == 0 &&
                  (icmp->icmp6_type == ND_NEIGHBOR_SOLICIT ||
                   icmp->icmp6_type == ND_NEIGHBOR_ADVERT)) {
                  struct in6_addr *nd_target;
                  struct nd_opt_hdr *nd_opt;
  
                  l4_len += sizeof *nd_target;
                  nd_target = ofpbuf_put_zeros(b, sizeof *nd_target);
                  *nd_target = flow->nd_target;
  
                  if (!eth_addr_is_zero(flow->arp_sha)) {
                      l4_len += 8;
                      nd_opt = ofpbuf_put_zeros(b, 8);
                      nd_opt->nd_opt_len = 1;
                      nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
                      memcpy(nd_opt + 1, flow->arp_sha, ETH_ADDR_LEN);
                  }
                  if (!eth_addr_is_zero(flow->arp_tha)) {
                      l4_len += 8;
                      nd_opt = ofpbuf_put_zeros(b, 8);
                      nd_opt->nd_opt_len = 1;
                      nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
                      memcpy(nd_opt + 1, flow->arp_tha, ETH_ADDR_LEN);
                  }
              }
              icmp->icmp6_cksum = (OVS_FORCE uint16_t)
                  csum(icmp, (char *)ofpbuf_tail(b) - (char *)icmp);
          }
      }
      return l4_len;
  }
  
  /* Puts into 'b' a packet that flow_extract() would parse as having the given
   * 'flow'.
   *
   * (This is useful only for testing, obviously, and the packet isn't really
   * valid. It hasn't got some checksums filled in, for one, and lots of fields
   * are just zeroed.) */
  void
  flow_compose(struct ofpbuf *b, const struct flow *flow)
  {
      size_t l4_len;
  
      /* eth_compose() sets l3 pointer and makes sure it is 32-bit aligned. */
      eth_compose(b, flow->dl_dst, flow->dl_src, ntohs(flow->dl_type), 0);
      if (flow->dl_type == htons(FLOW_DL_TYPE_NONE)) {
          struct eth_header *eth = ofpbuf_l2(b);
          eth->eth_type = htons(ofpbuf_size(b));
          return;
      }
  
      if (flow->vlan_tci & htons(VLAN_CFI)) {
          eth_push_vlan(b, htons(ETH_TYPE_VLAN), flow->vlan_tci);
      }
  
      if (flow->dl_type == htons(ETH_TYPE_IP)) {
          struct ip_header *ip;
  
          ip = ofpbuf_put_zeros(b, sizeof *ip);
          ip->ip_ihl_ver = IP_IHL_VER(5, 4);
          ip->ip_tos = flow->nw_tos;
          ip->ip_ttl = flow->nw_ttl;
          ip->ip_proto = flow->nw_proto;
          put_16aligned_be32(&ip->ip_src, flow->nw_src);
          put_16aligned_be32(&ip->ip_dst, flow->nw_dst);
  
          if (flow->nw_frag & FLOW_NW_FRAG_ANY) {
              ip->ip_frag_off |= htons(IP_MORE_FRAGMENTS);
              if (flow->nw_frag & FLOW_NW_FRAG_LATER) {
                  ip->ip_frag_off |= htons(100);
              }
          }
  
          ofpbuf_set_l4(b, ofpbuf_tail(b));
  
          l4_len = flow_compose_l4(b, flow);
  
          ip = ofpbuf_l3(b);
          ip->ip_tot_len = htons(b->l4_ofs - b->l3_ofs + l4_len);
          ip->ip_csum = csum(ip, sizeof *ip);
      } else if (flow->dl_type == htons(ETH_TYPE_IPV6)) {
          struct ovs_16aligned_ip6_hdr *nh;
  
          nh = ofpbuf_put_zeros(b, sizeof *nh);
          put_16aligned_be32(&nh->ip6_flow, htonl(6 << 28) |
                             htonl(flow->nw_tos << 20) | flow->ipv6_label);
          nh->ip6_hlim = flow->nw_ttl;
          nh->ip6_nxt = flow->nw_proto;
  
          memcpy(&nh->ip6_src, &flow->ipv6_src, sizeof(nh->ip6_src));
          memcpy(&nh->ip6_dst, &flow->ipv6_dst, sizeof(nh->ip6_dst));
  
          ofpbuf_set_l4(b, ofpbuf_tail(b));
  
          l4_len = flow_compose_l4(b, flow);
  
          nh = ofpbuf_l3(b);
          nh->ip6_plen = htons(l4_len);
      } else if (flow->dl_type == htons(ETH_TYPE_ARP) ||
                 flow->dl_type == htons(ETH_TYPE_RARP)) {
          struct arp_eth_header *arp;
  
          arp = ofpbuf_put_zeros(b, sizeof *arp);
          ofpbuf_set_l3(b, arp);
          arp->ar_hrd = htons(1);
          arp->ar_pro = htons(ETH_TYPE_IP);
          arp->ar_hln = ETH_ADDR_LEN;
          arp->ar_pln = 4;
          arp->ar_op = htons(flow->nw_proto);
  
          if (flow->nw_proto == ARP_OP_REQUEST ||
              flow->nw_proto == ARP_OP_REPLY) {
              put_16aligned_be32(&arp->ar_spa, flow->nw_src);
              put_16aligned_be32(&arp->ar_tpa, flow->nw_dst);
              memcpy(arp->ar_sha, flow->arp_sha, ETH_ADDR_LEN);
              memcpy(arp->ar_tha, flow->arp_tha, ETH_ADDR_LEN);
          }
      }
  
      if (eth_type_mpls(flow->dl_type)) {
          int n;
  
          b->l2_5_ofs = b->l3_ofs;
          for (n = 1; n < FLOW_MAX_MPLS_LABELS; n++) {
              if (flow->mpls_lse[n - 1] & htonl(MPLS_BOS_MASK)) {
                  break;
              }
          }
          while (n > 0) {
              push_mpls(b, flow->dl_type, flow->mpls_lse[--n]);
          }
      }
  }
  
  /* Compressed flow. */
  
  static int
  miniflow_n_values(const struct miniflow *flow)
  {
      return count_1bits(flow->map);
  }
  
  static uint32_t *
  miniflow_alloc_values(struct miniflow *flow, int n)
  {
      int size = MINIFLOW_VALUES_SIZE(n);
  
      if (size <= sizeof flow->inline_values) {
          flow->values_inline = true;
          return flow->inline_values;
      } else {
          COVERAGE_INC(miniflow_malloc);
          flow->values_inline = false;
          flow->offline_values = xmalloc(size);
          return flow->offline_values;
      }
  }
  
  /* Completes an initialization of 'dst' as a miniflow copy of 'src' begun by
   * the caller.  The caller must have already initialized 'dst->map' properly
   * to indicate the significant uint32_t elements of 'src'.  'n' must be the
   * number of 1-bits in 'dst->map'.
   *
   * Normally the significant elements are the ones that are non-zero.  However,
   * when a miniflow is initialized from a (mini)mask, the values can be zeroes,
   * so that the flow and mask always have the same maps.
   *
   * This function initializes values (either inline if possible or with
   * malloc() otherwise) and copies the uint32_t elements of 'src' indicated by
   * 'dst->map' into it. */
  static void
  miniflow_init__(struct miniflow *dst, const struct flow *src, int n)
  {
      const uint32_t *src_u32 = (const uint32_t *) src;
      uint32_t *dst_u32 = miniflow_alloc_values(dst, n);
      uint64_t map;
  
      for (map = dst->map; map; map = zero_rightmost_1bit(map)) {
          *dst_u32++ = src_u32[raw_ctz(map)];
      }
  }
  
  /* Initializes 'dst' as a copy of 'src'.  The caller must eventually free 'dst'
   * with miniflow_destroy().
   * Always allocates offline storage. */
  void
  miniflow_init(struct miniflow *dst, const struct flow *src)
  {
      const uint32_t *src_u32 = (const uint32_t *) src;
      unsigned int i;
      int n;
  
      /* Initialize dst->map, counting the number of nonzero elements. */
      n = 0;
      dst->map = 0;
  
      for (i = 0; i < FLOW_U32S; i++) {
          if (src_u32[i]) {
              dst->map |= UINT64_C(1) << i;
              n++;
          }
      }
  
      miniflow_init__(dst, src, n);
  }
  
  /* Initializes 'dst' as a copy of 'src', using 'mask->map' as 'dst''s map.  The
   * caller must eventually free 'dst' with miniflow_destroy(). */
  void
  miniflow_init_with_minimask(struct miniflow *dst, const struct flow *src,
                              const struct minimask *mask)
  {
      dst->map = mask->masks.map;
      miniflow_init__(dst, src, miniflow_n_values(dst));
  }
  
  /* Initializes 'dst' as a copy of 'src'.  The caller must eventually free 'dst'
   * with miniflow_destroy(). */
  void
  miniflow_clone(struct miniflow *dst, const struct miniflow *src)
  {
      int size = MINIFLOW_VALUES_SIZE(miniflow_n_values(src));
      uint32_t *values;
  
      dst->map = src->map;
      if (size <= sizeof dst->inline_values) {
          dst->values_inline = true;
          values = dst->inline_values;
      } else {
          dst->values_inline = false;
          COVERAGE_INC(miniflow_malloc);
          dst->offline_values = xmalloc(size);
          values = dst->offline_values;
      }
      memcpy(values, miniflow_get_values(src), size);
  }
  
  /* Initializes 'dst' as a copy of 'src'.  The caller must have allocated
   * 'dst' to have inline space all data in 'src'. */
  void
  miniflow_clone_inline(struct miniflow *dst, const struct miniflow *src,
                        size_t n_values)
  {
      dst->values_inline = true;
      dst->map = src->map;
      memcpy(dst->inline_values, miniflow_get_values(src),
             MINIFLOW_VALUES_SIZE(n_values));
  }
  
  /* Initializes 'dst' with the data in 'src', destroying 'src'.
   * The caller must eventually free 'dst' with miniflow_destroy().
   * 'dst' must be regularly sized miniflow, but 'src' can have
   * storage for more than the default MINI_N_INLINE inline
   * values. */
  void
  miniflow_move(struct miniflow *dst, struct miniflow *src)
  {
      int size = MINIFLOW_VALUES_SIZE(miniflow_n_values(src));
  
      dst->map = src->map;
      if (size <= sizeof dst->inline_values) {
          dst->values_inline = true;
          memcpy(dst->inline_values, miniflow_get_values(src), size);
          miniflow_destroy(src);
      } else if (src->values_inline) {
          dst->values_inline = false;
          COVERAGE_INC(miniflow_malloc);
          dst->offline_values = xmalloc(size);
          memcpy(dst->offline_values, src->inline_values, size);
      } else {
          dst->values_inline = false;
          dst->offline_values = src->offline_values;
      }
  }
  
  /* Frees any memory owned by 'flow'.  Does not free the storage in which 'flow'
   * itself resides; the caller is responsible for that. */
  void
  miniflow_destroy(struct miniflow *flow)
  {
      if (!flow->values_inline) {
          free(flow->offline_values);
      }
  }
  
  /* Initializes 'dst' as a copy of 'src'. */
  void
  miniflow_expand(const struct miniflow *src, struct flow *dst)
  {
      memset(dst, 0, sizeof *dst);
      flow_union_with_miniflow(dst, src);
  }
  
  /* Returns the uint32_t that would be at byte offset '4 * u32_ofs' if 'flow'
   * were expanded into a "struct flow". */
  static uint32_t
  miniflow_get(const struct miniflow *flow, unsigned int u32_ofs)
  {
      return (flow->map & UINT64_C(1) << u32_ofs)
          ? *(miniflow_get_u32_values(flow) +
              count_1bits(flow->map & ((UINT64_C(1) << u32_ofs) - 1)))
          : 0;
  }
  
  /* Returns true if 'a' and 'b' are the equal miniflow, false otherwise. */
  bool
  miniflow_equal(const struct miniflow *a, const struct miniflow *b)
  {
      const uint32_t *ap = miniflow_get_u32_values(a);
      const uint32_t *bp = miniflow_get_u32_values(b);
      const uint64_t a_map = a->map;
      const uint64_t b_map = b->map;
  
      if (OVS_LIKELY(a_map == b_map)) {
          int count = miniflow_n_values(a);
  
          return !memcmp(ap, bp, count * sizeof *ap);
      } else {
          uint64_t map;
  
          for (map = a_map | b_map; map; map = zero_rightmost_1bit(map)) {
              uint64_t bit = rightmost_1bit(map);
              uint64_t a_value = a_map & bit ? *ap++ : 0;
              uint64_t b_value = b_map & bit ? *bp++ : 0;
  
              if (a_value != b_value) {
                  return false;
              }
          }
      }
  
      return true;
  }
  
  /* Returns true if 'a' and 'b' are equal at the places where there are 1-bits
   * in 'mask', false if they differ. */
  bool
  miniflow_equal_in_minimask(const struct miniflow *a, const struct miniflow *b,
                             const struct minimask *mask)
  {
      const uint32_t *p = miniflow_get_u32_values(&mask->masks);
      uint64_t map;
  
      for (map = mask->masks.map; map; map = zero_rightmost_1bit(map)) {
          int ofs = raw_ctz(map);
  
          if ((miniflow_get(a, ofs) ^ miniflow_get(b, ofs)) & *p++) {
              return false;
          }
      }
  
      return true;
  }
  
  /* Returns true if 'a' and 'b' are equal at the places where there are 1-bits
   * in 'mask', false if they differ. */
  bool
  miniflow_equal_flow_in_minimask(const struct miniflow *a, const struct flow *b,
                                  const struct minimask *mask)
  {
      const uint32_t *b_u32 = (const uint32_t *) b;
      const uint32_t *p = miniflow_get_u32_values(&mask->masks);
      uint64_t map;
  
      for (map = mask->masks.map; map; map = zero_rightmost_1bit(map)) {
          int ofs = raw_ctz(map);
  
          if ((miniflow_get(a, ofs) ^ b_u32[ofs]) & *p++) {
              return false;
          }
      }
  
      return true;
  }
  
  
  /* Initializes 'dst' as a copy of 'src'.  The caller must eventually free 'dst'
   * with minimask_destroy(). */
  void
  minimask_init(struct minimask *mask, const struct flow_wildcards *wc)
  {
      miniflow_init(&mask->masks, &wc->masks);
  }
  
  /* Initializes 'dst' as a copy of 'src'.  The caller must eventually free 'dst'
   * with minimask_destroy(). */
  void
  minimask_clone(struct minimask *dst, const struct minimask *src)
  {
      miniflow_clone(&dst->masks, &src->masks);
  }
  
  /* Initializes 'dst' with the data in 'src', destroying 'src'.
   * The caller must eventually free 'dst' with minimask_destroy(). */
  void
  minimask_move(struct minimask *dst, struct minimask *src)
  {
      miniflow_move(&dst->masks, &src->masks);
  }
  
  /* Initializes 'dst_' as the bit-wise "and" of 'a_' and 'b_'.
   *
   * The caller must provide room for FLOW_U32S "uint32_t"s in 'storage', for use
   * by 'dst_'.  The caller must *not* free 'dst_' with minimask_destroy(). */
  void
  minimask_combine(struct minimask *dst_,
                   const struct minimask *a_, const struct minimask *b_,
                   uint32_t storage[FLOW_U32S])
  {
      struct miniflow *dst = &dst_->masks;
      uint32_t *dst_values = storage;
      const struct miniflow *a = &a_->masks;
      const struct miniflow *b = &b_->masks;
      uint64_t map;
      int n = 0;
  
      dst->values_inline = false;
      dst->offline_values = storage;
  
      dst->map = 0;
      for (map = a->map & b->map; map; map = zero_rightmost_1bit(map)) {
          int ofs = raw_ctz(map);
          uint32_t mask = miniflow_get(a, ofs) & miniflow_get(b, ofs);
  
          if (mask) {
              dst->map |= rightmost_1bit(map);
              dst_values[n++] = mask;
          }
      }
  }
  
  /* Frees any memory owned by 'mask'.  Does not free the storage in which 'mask'
   * itself resides; the caller is responsible for that. */
  void
  minimask_destroy(struct minimask *mask)
  {
      miniflow_destroy(&mask->masks);
  }
  
  /* Initializes 'dst' as a copy of 'src'. */
  void
  minimask_expand(const struct minimask *mask, struct flow_wildcards *wc)
  {
      miniflow_expand(&mask->masks, &wc->masks);
  }
  
  /* Returns the uint32_t that would be at byte offset '4 * u32_ofs' if 'mask'
   * were expanded into a "struct flow_wildcards". */
  uint32_t
  minimask_get(const struct minimask *mask, unsigned int u32_ofs)
  {
      return miniflow_get(&mask->masks, u32_ofs);
  }
  
  /* Returns true if 'a' and 'b' are the same flow mask, false otherwise.  */
  bool
  minimask_equal(const struct minimask *a, const struct minimask *b)
  {
      return miniflow_equal(&a->masks, &b->masks);
  }
  
  /* Returns true if at least one bit matched by 'b' is wildcarded by 'a',
   * false otherwise. */
  bool
  minimask_has_extra(const struct minimask *a, const struct minimask *b)
  {
      const uint32_t *p = miniflow_get_u32_values(&b->masks);
      uint64_t map;
  
      for (map = b->masks.map; map; map = zero_rightmost_1bit(map)) {
          uint32_t a_u32 = minimask_get(a, raw_ctz(map));
          uint32_t b_u32 = *p++;
  
          if ((a_u32 & b_u32) != b_u32) {
              return true;
          }
      }
  
      return false;
  }
  