text: /*
   * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 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.
   */
  
  #ifndef PACKETS_H
  #define PACKETS_H 1
  
  #include <inttypes.h>
  #include <sys/types.h>
  #include <stdint.h>
  #include <string.h>
  #include "compiler.h"
  #include "openvswitch/geneve.h"
  #include "openvswitch/packets.h"
  #include "openvswitch/types.h"
  #include "openvswitch/nsh.h"
  #include "odp-netlink.h"
  #include "random.h"
  #include "hash.h"
  #include "tun-metadata.h"
  #include "unaligned.h"
  #include "util.h"
  #include "timeval.h"
  
  struct dp_packet;
  struct conn;
  struct ds;
  
  /* Purely internal to OVS userspace. These flags should never be exposed to
   * the outside world and so aren't included in the flags mask. */
  
  /* Tunnel information is in userspace datapath format. */
  #define FLOW_TNL_F_UDPIF (1 << 4)
  
  static inline bool ipv6_addr_is_set(const struct in6_addr *addr);
  
  static inline bool
  flow_tnl_dst_is_set(const struct flow_tnl *tnl)
  {
      return tnl->ip_dst || ipv6_addr_is_set(&tnl->ipv6_dst);
  }
  
  struct in6_addr flow_tnl_dst(const struct flow_tnl *tnl);
  struct in6_addr flow_tnl_src(const struct flow_tnl *tnl);
  
  /* Returns an offset to 'src' covering all the meaningful fields in 'src'. */
  static inline size_t
  flow_tnl_size(const struct flow_tnl *src)
  {
      if (!flow_tnl_dst_is_set(src)) {
          /* Covers ip_dst and ipv6_dst only. */
          return offsetof(struct flow_tnl, ip_src);
      }
      if (src->flags & FLOW_TNL_F_UDPIF) {
          /* Datapath format, cover all options we have. */
          return offsetof(struct flow_tnl, metadata.opts)
              + src->metadata.present.len;
      }
      if (!src->metadata.present.map) {
          /* No TLVs, opts is irrelevant. */
          return offsetof(struct flow_tnl, metadata.opts);
      }
      /* Have decoded TLVs, opts is relevant. */
      return sizeof *src;
  }
  
  /* Copy flow_tnl, but avoid copying unused portions of tun_metadata.  Unused
   * data in 'dst' is NOT cleared, so this must not be used in cases where the
   * uninitialized portion may be hashed over. */
  static inline void
  flow_tnl_copy__(struct flow_tnl *dst, const struct flow_tnl *src)
  {
      memcpy(dst, src, flow_tnl_size(src));
  }
  
  static inline bool
  flow_tnl_equal(const struct flow_tnl *a, const struct flow_tnl *b)
  {
      size_t a_size = flow_tnl_size(a);
  
      return a_size == flow_tnl_size(b) && !memcmp(a, b, a_size);
  }
  
  /* Datapath packet metadata */
  struct pkt_metadata {
  PADDED_MEMBERS_CACHELINE_MARKER(CACHE_LINE_SIZE, cacheline0,
      uint32_t recirc_id;         /* Recirculation id carried with the
                                     recirculating packets. 0 for packets
                                     received from the wire. */
      uint32_t dp_hash;           /* hash value computed by the recirculation
                                     action. */
      uint32_t skb_priority;      /* Packet priority for QoS. */
      uint32_t pkt_mark;          /* Packet mark. */
      uint8_t  ct_state;          /* Connection state. */
      bool ct_orig_tuple_ipv6;
      uint16_t ct_zone;           /* Connection zone. */
      uint32_t ct_mark;           /* Connection mark. */
      ovs_u128 ct_label;          /* Connection label. */
      union flow_in_port in_port; /* Input port. */
      struct conn *conn;          /* Cached conntrack connection. */
      bool reply;                 /* True if reply direction. */
      bool icmp_related;          /* True if ICMP related. */
  );
  
  PADDED_MEMBERS_CACHELINE_MARKER(CACHE_LINE_SIZE, cacheline1,
      union {                     /* Populated only for non-zero 'ct_state'. */
          struct ovs_key_ct_tuple_ipv4 ipv4;
          struct ovs_key_ct_tuple_ipv6 ipv6;   /* Used only if                */
      } ct_orig_tuple;                         /* 'ct_orig_tuple_ipv6' is set */
  );
  
  PADDED_MEMBERS_CACHELINE_MARKER(CACHE_LINE_SIZE, cacheline2,
      struct flow_tnl tunnel;     /* Encapsulating tunnel parameters. Note that
                                   * if 'ip_dst' == 0, the rest of the fields may
                                   * be uninitialized. */
  );
  };
  
  BUILD_ASSERT_DECL(offsetof(struct pkt_metadata, cacheline0) == 0);
  BUILD_ASSERT_DECL(offsetof(struct pkt_metadata, cacheline1) ==
                    CACHE_LINE_SIZE);
  BUILD_ASSERT_DECL(offsetof(struct pkt_metadata, cacheline2) ==
                    2 * CACHE_LINE_SIZE);
  
  static inline void
  pkt_metadata_init_tnl(struct pkt_metadata *md)
  {
      /* Zero up through the tunnel metadata options. The length and table
       * are before this and as long as they are empty, the options won't
       * be looked at. */
      memset(md, 0, offsetof(struct pkt_metadata, tunnel.metadata.opts));
  }
  
  static inline void
  pkt_metadata_init_conn(struct pkt_metadata *md)
  {
      md->conn = NULL;
  }
  
  static inline void
  pkt_metadata_init(struct pkt_metadata *md, odp_port_t port)
  {
      /* This is called for every packet in userspace datapath and affects
       * performance if all the metadata is initialized. Hence, fields should
       * only be zeroed out when necessary.
       *
       * Initialize only till ct_state. Once the ct_state is zeroed out rest
       * of ct fields will not be looked at unless ct_state != 0.
       */
      memset(md, 0, offsetof(struct pkt_metadata, ct_orig_tuple_ipv6));
  
      /* It can be expensive to zero out all of the tunnel metadata. However,
       * we can just zero out ip_dst and the rest of the data will never be
       * looked at. */
      md->tunnel.ip_dst = 0;
      md->tunnel.ipv6_dst = in6addr_any;
      md->in_port.odp_port = port;
      md->conn = NULL;
  }
  
  /* This function prefetches the cachelines touched by pkt_metadata_init()
   * and pkt_metadata_init_tnl().  For performance reasons the two functions
   * should be kept in sync. */
  static inline void
  pkt_metadata_prefetch_init(struct pkt_metadata *md)
  {
      /* Prefetch cacheline0 as members till ct_state and odp_port will
       * be initialized later in pkt_metadata_init(). */
      OVS_PREFETCH(md->cacheline0);
  
      /* Prefetch cacheline1 as members of this cacheline will be zeroed out
       * in pkt_metadata_init_tnl(). */
      OVS_PREFETCH(md->cacheline1);
  
      /* Prefetch cachline2 as ip_dst & ipv6_dst fields will be initialized. */
      OVS_PREFETCH(md->cacheline2);
  }
  
  bool dpid_from_string(const char *s, uint64_t *dpidp);
  
  #define ETH_ADDR_LEN           6
  
  static const struct eth_addr eth_addr_broadcast OVS_UNUSED
      = ETH_ADDR_C(ff,ff,ff,ff,ff,ff);
  
  static const struct eth_addr eth_addr_exact OVS_UNUSED
      = ETH_ADDR_C(ff,ff,ff,ff,ff,ff);
  
  static const struct eth_addr eth_addr_zero OVS_UNUSED
      = ETH_ADDR_C(00,00,00,00,00,00);
  static const struct eth_addr64 eth_addr64_zero OVS_UNUSED
      = ETH_ADDR64_C(00,00,00,00,00,00,00,00);
  
  static const struct eth_addr eth_addr_stp OVS_UNUSED
      = ETH_ADDR_C(01,80,c2,00,00,00);
  
  static const struct eth_addr eth_addr_lacp OVS_UNUSED
      = ETH_ADDR_C(01,80,c2,00,00,02);
  
  static const struct eth_addr eth_addr_bfd OVS_UNUSED
      = ETH_ADDR_C(00,23,20,00,00,01);
  
  static inline bool eth_addr_is_broadcast(const struct eth_addr a)
  {
      return (a.be16[0] & a.be16[1] & a.be16[2]) == htons(0xffff);
  }
  
  static inline bool eth_addr_is_multicast(const struct eth_addr a)
  {
      return a.ea[0] & 1;
  }
  
  static inline bool eth_addr_is_local(const struct eth_addr a)
  {
      /* Local if it is either a locally administered address or a Nicira random
       * address. */
      return a.ea[0] & 2
          || (a.be16[0] == htons(0x0023)
              && (a.be16[1] & htons(0xff80)) == htons(0x2080));
  }
  static inline bool eth_addr_is_zero(const struct eth_addr a)
  {
      return !(a.be16[0] | a.be16[1] | a.be16[2]);
  }
  static inline bool eth_addr64_is_zero(const struct eth_addr64 a)
  {
      return !(a.be16[0] | a.be16[1] | a.be16[2] | a.be16[3]);
  }
  
  static inline int eth_mask_is_exact(const struct eth_addr a)
  {
      return (a.be16[0] & a.be16[1] & a.be16[2]) == htons(0xffff);
  }
  
  static inline int eth_addr_compare_3way(const struct eth_addr a,
                                          const struct eth_addr b)
  {
      return memcmp(&a, &b, sizeof a);
  }
  static inline int eth_addr64_compare_3way(const struct eth_addr64 a,
                                            const struct eth_addr64 b)
  {
      return memcmp(&a, &b, sizeof a);
  }
  
  static inline bool eth_addr_equals(const struct eth_addr a,
                                     const struct eth_addr b)
  {
      return !eth_addr_compare_3way(a, b);
  }
  static inline bool eth_addr64_equals(const struct eth_addr64 a,
                                       const struct eth_addr64 b)
  {
      return !eth_addr64_compare_3way(a, b);
  }
  
  static inline bool eth_addr_equal_except(const struct eth_addr a,
                                           const struct eth_addr b,
                                           const struct eth_addr mask)
  {
      return !(((a.be16[0] ^ b.be16[0]) & mask.be16[0])
               || ((a.be16[1] ^ b.be16[1]) & mask.be16[1])
               || ((a.be16[2] ^ b.be16[2]) & mask.be16[2]));
  }
  
  static inline uint64_t eth_addr_to_uint64(const struct eth_addr ea)
  {
      return (((uint64_t) ntohs(ea.be16[0]) << 32)
              | ((uint64_t) ntohs(ea.be16[1]) << 16)
              | ntohs(ea.be16[2]));
  }
  
  static inline uint64_t eth_addr_vlan_to_uint64(const struct eth_addr ea,
                                                 uint16_t vlan)
  {
      return (((uint64_t)vlan << 48) | eth_addr_to_uint64(ea));
  }
  
  static inline void eth_addr_from_uint64(uint64_t x, struct eth_addr *ea)
  {
      ea->be16[0] = htons(x >> 32);
      ea->be16[1] = htons((x & 0xFFFF0000) >> 16);
      ea->be16[2] = htons(x & 0xFFFF);
  }
  
  static inline struct eth_addr eth_addr_invert(const struct eth_addr src)
  {
      struct eth_addr dst;
  
      for (int i = 0; i < ARRAY_SIZE(src.be16); i++) {
          dst.be16[i] = ~src.be16[i];
      }
  
      return dst;
  }
  
  static inline void eth_addr_mark_random(struct eth_addr *ea)
  {
      ea->ea[0] &= ~1;                /* Unicast. */
      ea->ea[0] |= 2;                 /* Private. */
  }
  
  static inline void eth_addr_random(struct eth_addr *ea)
  {
      random_bytes((uint8_t *)ea, sizeof *ea);
      eth_addr_mark_random(ea);
  }
  
  static inline void eth_addr_nicira_random(struct eth_addr *ea)
  {
      eth_addr_random(ea);
  
      /* Set the OUI to the Nicira one. */
      ea->ea[0] = 0x00;
      ea->ea[1] = 0x23;
      ea->ea[2] = 0x20;
  
      /* Set the top bit to indicate random Nicira address. */
      ea->ea[3] |= 0x80;
  }
  static inline uint32_t hash_mac(const struct eth_addr ea,
                                  const uint16_t vlan, const uint32_t basis)
  {
      return hash_uint64_basis(eth_addr_vlan_to_uint64(ea, vlan), basis);
  }
  
  bool eth_addr_is_reserved(const struct eth_addr);
  bool eth_addr_from_string(const char *, struct eth_addr *);
  
  void compose_rarp(struct dp_packet *, const struct eth_addr);
  
  void eth_push_vlan(struct dp_packet *, ovs_be16 tpid, ovs_be16 tci);
  void eth_pop_vlan(struct dp_packet *);
  
  const char *eth_from_hex(const char *hex, struct dp_packet **packetp);
  void eth_format_masked(const struct eth_addr ea,
                         const struct eth_addr *mask, struct ds *s);
  
  void set_mpls_lse(struct dp_packet *, ovs_be32 label);
  void push_mpls(struct dp_packet *packet, ovs_be16 ethtype, ovs_be32 lse);
  void pop_mpls(struct dp_packet *, ovs_be16 ethtype);
  
  void set_mpls_lse_ttl(ovs_be32 *lse, uint8_t ttl);
  void set_mpls_lse_tc(ovs_be32 *lse, uint8_t tc);
  void set_mpls_lse_label(ovs_be32 *lse, ovs_be32 label);
  void set_mpls_lse_bos(ovs_be32 *lse, uint8_t bos);
  ovs_be32 set_mpls_lse_values(uint8_t ttl, uint8_t tc, uint8_t bos,
                               ovs_be32 label);
  
  /* Example:
   *
   * struct eth_addr mac;
   *    [...]
   * printf("The Ethernet address is "ETH_ADDR_FMT"\n", ETH_ADDR_ARGS(mac));
   *
   */
  #define ETH_ADDR_FMT                                                    \
      "%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8
  #define ETH_ADDR_ARGS(EA) ETH_ADDR_BYTES_ARGS((EA).ea)
  #define ETH_ADDR_BYTES_ARGS(EAB) \
           (EAB)[0], (EAB)[1], (EAB)[2], (EAB)[3], (EAB)[4], (EAB)[5]
  #define ETH_ADDR_STRLEN 17
  
  /* Example:
   *
   * struct eth_addr64 eui64;
   *    [...]
   * printf("The EUI-64 address is "ETH_ADDR64_FMT"\n", ETH_ADDR64_ARGS(mac));
   *
   */
  #define ETH_ADDR64_FMT \
      "%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":" \
      "%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8
  #define ETH_ADDR64_ARGS(EA) ETH_ADDR64_BYTES_ARGS((EA).ea64)
  #define ETH_ADDR64_BYTES_ARGS(EAB) \
           (EAB)[0], (EAB)[1], (EAB)[2], (EAB)[3], \
           (EAB)[4], (EAB)[5], (EAB)[6], (EAB)[7]
  #define ETH_ADDR64_STRLEN 23
  
  /* Example:
   *
   * char *string = "1 00:11:22:33:44:55 2";
   * struct eth_addr mac;
   * int a, b;
   *
   * if (ovs_scan(string, "%d"ETH_ADDR_SCAN_FMT"%d",
   *              &a, ETH_ADDR_SCAN_ARGS(mac), &b)) {
   *     ...
   * }
   */
  #define ETH_ADDR_SCAN_FMT "%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8
  #define ETH_ADDR_SCAN_ARGS(EA) \
      &(EA).ea[0], &(EA).ea[1], &(EA).ea[2], &(EA).ea[3], &(EA).ea[4], &(EA).ea[5]
  
  #define ETH_TYPE_IP            0x0800
  #define ETH_TYPE_ARP           0x0806
  #define ETH_TYPE_TEB           0x6558
  #define ETH_TYPE_VLAN_8021Q    0x8100
  #define ETH_TYPE_VLAN          ETH_TYPE_VLAN_8021Q
  #define ETH_TYPE_VLAN_8021AD   0x88a8
  #define ETH_TYPE_IPV6          0x86dd
  #define ETH_TYPE_LACP          0x8809
  #define ETH_TYPE_RARP          0x8035
  #define ETH_TYPE_MPLS          0x8847
  #define ETH_TYPE_MPLS_MCAST    0x8848
  #define ETH_TYPE_NSH           0x894f
  #define ETH_TYPE_ERSPAN1       0x88be   /* version 1 type II */
  #define ETH_TYPE_ERSPAN2       0x22eb   /* version 2 type III */
  
  static inline bool eth_type_mpls(ovs_be16 eth_type)
  {
      return eth_type == htons(ETH_TYPE_MPLS) ||
          eth_type == htons(ETH_TYPE_MPLS_MCAST);
  }
  
  static inline bool eth_type_vlan(ovs_be16 eth_type)
  {
      return eth_type == htons(ETH_TYPE_VLAN_8021Q) ||
          eth_type == htons(ETH_TYPE_VLAN_8021AD);
  }
  
  
  /* Minimum value for an Ethernet type.  Values below this are IEEE 802.2 frame
   * lengths. */
  #define ETH_TYPE_MIN           0x600
  
  #define ETH_HEADER_LEN 14
  #define ETH_PAYLOAD_MIN 46
  #define ETH_PAYLOAD_MAX 1500
  #define ETH_TOTAL_MIN (ETH_HEADER_LEN + ETH_PAYLOAD_MIN)
  #define ETH_TOTAL_MAX (ETH_HEADER_LEN + ETH_PAYLOAD_MAX)
  #define ETH_VLAN_TOTAL_MAX (ETH_HEADER_LEN + VLAN_HEADER_LEN + ETH_PAYLOAD_MAX)
  struct eth_header {
      struct eth_addr eth_dst;
      struct eth_addr eth_src;
      ovs_be16 eth_type;
  };
  BUILD_ASSERT_DECL(ETH_HEADER_LEN == sizeof(struct eth_header));
  
  void push_eth(struct dp_packet *packet, const struct eth_addr *dst,
                const struct eth_addr *src);
  void pop_eth(struct dp_packet *packet);
  
  void push_nsh(struct dp_packet *packet, const struct nsh_hdr *nsh_hdr_src);
  bool pop_nsh(struct dp_packet *packet);
  
  #define LLC_DSAP_SNAP 0xaa
  #define LLC_SSAP_SNAP 0xaa
  #define LLC_CNTL_SNAP 3
  
  #define LLC_HEADER_LEN 3
  struct llc_header {
      uint8_t llc_dsap;
      uint8_t llc_ssap;
      uint8_t llc_cntl;
  };
  BUILD_ASSERT_DECL(LLC_HEADER_LEN == sizeof(struct llc_header));
  
  /* LLC field values used for STP frames. */
  #define STP_LLC_SSAP 0x42
  #define STP_LLC_DSAP 0x42
  #define STP_LLC_CNTL 0x03
  
  #define SNAP_ORG_ETHERNET "\0\0" /* The compiler adds a null byte, so
                                      sizeof(SNAP_ORG_ETHERNET) == 3. */
  #define SNAP_HEADER_LEN 5
  OVS_PACKED(
  struct snap_header {
      uint8_t snap_org[3];
      ovs_be16 snap_type;
  });
  BUILD_ASSERT_DECL(SNAP_HEADER_LEN == sizeof(struct snap_header));
  
  #define LLC_SNAP_HEADER_LEN (LLC_HEADER_LEN + SNAP_HEADER_LEN)
  OVS_PACKED(
  struct llc_snap_header {
      struct llc_header llc;
      struct snap_header snap;
  });
  BUILD_ASSERT_DECL(LLC_SNAP_HEADER_LEN == sizeof(struct llc_snap_header));
  
  #define VLAN_VID_MASK 0x0fff
  #define VLAN_VID_SHIFT 0
  
  #define VLAN_PCP_MASK 0xe000
  #define VLAN_PCP_SHIFT 13
  
  #define VLAN_CFI 0x1000
  #define VLAN_CFI_SHIFT 12
  
  /* Given the vlan_tci field from an 802.1Q header, in network byte order,
   * returns the VLAN ID in host byte order. */
  static inline uint16_t
  vlan_tci_to_vid(ovs_be16 vlan_tci)
  {
      return (ntohs(vlan_tci) & VLAN_VID_MASK) >> VLAN_VID_SHIFT;
  }
  
  /* Given the vlan_tci field from an 802.1Q header, in network byte order,
   * returns the priority code point (PCP) in host byte order. */
  static inline int
  vlan_tci_to_pcp(ovs_be16 vlan_tci)
  {
      return (ntohs(vlan_tci) & VLAN_PCP_MASK) >> VLAN_PCP_SHIFT;
  }
  
  /* Given the vlan_tci field from an 802.1Q header, in network byte order,
   * returns the Canonical Format Indicator (CFI). */
  static inline int
  vlan_tci_to_cfi(ovs_be16 vlan_tci)
  {
      return (vlan_tci & htons(VLAN_CFI)) != 0;
  }
  
  #define VLAN_HEADER_LEN 4
  struct vlan_header {
      ovs_be16 vlan_tci;          /* Lowest 12 bits are VLAN ID. */
      ovs_be16 vlan_next_type;
  };
  BUILD_ASSERT_DECL(VLAN_HEADER_LEN == sizeof(struct vlan_header));
  
  #define VLAN_ETH_HEADER_LEN (ETH_HEADER_LEN + VLAN_HEADER_LEN)
  struct vlan_eth_header {
      struct eth_addr veth_dst;
      struct eth_addr veth_src;
      ovs_be16 veth_type;         /* Always htons(ETH_TYPE_VLAN). */
      ovs_be16 veth_tci;          /* Lowest 12 bits are VLAN ID. */
      ovs_be16 veth_next_type;
  };
  BUILD_ASSERT_DECL(VLAN_ETH_HEADER_LEN == sizeof(struct vlan_eth_header));
  
  /* MPLS related definitions */
  #define MPLS_TTL_MASK       0x000000ff
  #define MPLS_TTL_SHIFT      0
  
  #define MPLS_BOS_MASK       0x00000100
  #define MPLS_BOS_SHIFT      8
  
  #define MPLS_TC_MASK        0x00000e00
  #define MPLS_TC_SHIFT       9
  
  #define MPLS_LABEL_MASK     0xfffff000
  #define MPLS_LABEL_SHIFT    12
  
  #define MPLS_HLEN           4
  
  struct mpls_hdr {
      ovs_16aligned_be32 mpls_lse;
  };
  BUILD_ASSERT_DECL(MPLS_HLEN == sizeof(struct mpls_hdr));
  
  /* Given a mpls label stack entry in network byte order
   * return mpls label in host byte order */
  static inline uint32_t
  mpls_lse_to_label(ovs_be32 mpls_lse)
  {
      return (ntohl(mpls_lse) & MPLS_LABEL_MASK) >> MPLS_LABEL_SHIFT;
  }
  
  /* Given a mpls label stack entry in network byte order
   * return mpls tc */
  static inline uint8_t
  mpls_lse_to_tc(ovs_be32 mpls_lse)
  {
      return (ntohl(mpls_lse) & MPLS_TC_MASK) >> MPLS_TC_SHIFT;
  }
  
  /* Given a mpls label stack entry in network byte order
   * return mpls ttl */
  static inline uint8_t
  mpls_lse_to_ttl(ovs_be32 mpls_lse)
  {
      return (ntohl(mpls_lse) & MPLS_TTL_MASK) >> MPLS_TTL_SHIFT;
  }
  
  /* Set label in mpls lse. */
  static inline void
  flow_set_mpls_lse_label(ovs_be32 *mpls_lse, uint32_t label)
  {
      *mpls_lse &= ~htonl(MPLS_LABEL_MASK);
      *mpls_lse |= htonl(label << MPLS_LABEL_SHIFT);
  }
  
  /* Set TC in mpls lse. */
  static inline void
  flow_set_mpls_lse_tc(ovs_be32 *mpls_lse, uint8_t tc)
  {
      *mpls_lse &= ~htonl(MPLS_TC_MASK);
      *mpls_lse |= htonl((tc & 0x7) << MPLS_TC_SHIFT);
  }
  
  /* Set BOS in mpls lse. */
  static inline void
  flow_set_mpls_lse_bos(ovs_be32 *mpls_lse, uint8_t bos)
  {
      *mpls_lse &= ~htonl(MPLS_BOS_MASK);
      *mpls_lse |= htonl((bos & 0x1) << MPLS_BOS_SHIFT);
  }
  
  /* Set TTL in mpls lse. */
  static inline void
  flow_set_mpls_lse_ttl(ovs_be32 *mpls_lse, uint8_t ttl)
  {
      *mpls_lse &= ~htonl(MPLS_TTL_MASK);
      *mpls_lse |= htonl(ttl << MPLS_TTL_SHIFT);
  }
  
  /* Given a mpls label stack entry in network byte order
   * return mpls BoS bit  */
  static inline uint8_t
  mpls_lse_to_bos(ovs_be32 mpls_lse)
  {
      return (mpls_lse & htonl(MPLS_BOS_MASK)) != 0;
  }
  
  #define IP_FMT "%"PRIu32".%"PRIu32".%"PRIu32".%"PRIu32
  #define IP_ARGS(ip)                             \
      ntohl(ip) >> 24,                            \
      (ntohl(ip) >> 16) & 0xff,                   \
      (ntohl(ip) >> 8) & 0xff,                    \
      ntohl(ip) & 0xff
  
  /* Example:
   *
   * char *string = "1 33.44.55.66 2";
   * ovs_be32 ip;
   * int a, b;
   *
   * if (ovs_scan(string, "%d"IP_SCAN_FMT"%d", &a, IP_SCAN_ARGS(&ip), &b)) {
   *     ...
   * }
   */
  #define IP_SCAN_FMT "%"SCNu8".%"SCNu8".%"SCNu8".%"SCNu8
  #define IP_SCAN_ARGS(ip)                                    \
          ((void) (ovs_be32) *(ip), &((uint8_t *) ip)[0]),    \
          &((uint8_t *) ip)[1],                               \
          &((uint8_t *) ip)[2],                               \
          &((uint8_t *) ip)[3]
  
  #define IP_PORT_SCAN_FMT "%"SCNu8".%"SCNu8".%"SCNu8".%"SCNu8":%"SCNu16
  #define IP_PORT_SCAN_ARGS(ip, port)                                    \
          ((void) (ovs_be32) *(ip), &((uint8_t *) ip)[0]),    \
          &((uint8_t *) ip)[1],                               \
          &((uint8_t *) ip)[2],                               \
          &((uint8_t *) ip)[3],                               \
          ((void) (ovs_be16) *(port), (uint16_t *) port)
  
  /* Returns true if 'netmask' is a CIDR netmask, that is, if it consists of N
   * high-order 1-bits and 32-N low-order 0-bits. */
  static inline bool
  ip_is_cidr(ovs_be32 netmask)
  {
      uint32_t x = ~ntohl(netmask);
      return !(x & (x + 1));
  }
  static inline bool
  ip_is_multicast(ovs_be32 ip)
  {
      return (ip & htonl(0xf0000000)) == htonl(0xe0000000);
  }
  static inline bool
  ip_is_local_multicast(ovs_be32 ip)
  {
      return (ip & htonl(0xffffff00)) == htonl(0xe0000000);
  }
  int ip_count_cidr_bits(ovs_be32 netmask);
  void ip_format_masked(ovs_be32 ip, ovs_be32 mask, struct ds *);
  bool ip_parse(const char *s, ovs_be32 *ip);
  char *ip_parse_port(const char *s, ovs_be32 *ip, ovs_be16 *port)
      OVS_WARN_UNUSED_RESULT;
  char *ip_parse_masked(const char *s, ovs_be32 *ip, ovs_be32 *mask)
      OVS_WARN_UNUSED_RESULT;
  char *ip_parse_cidr(const char *s, ovs_be32 *ip, unsigned int *plen)
      OVS_WARN_UNUSED_RESULT;
  char *ip_parse_masked_len(const char *s, int *n, ovs_be32 *ip, ovs_be32 *mask)
      OVS_WARN_UNUSED_RESULT;
  char *ip_parse_cidr_len(const char *s, int *n, ovs_be32 *ip,
                          unsigned int *plen)
      OVS_WARN_UNUSED_RESULT;
  
  #define IP_VER(ip_ihl_ver) ((ip_ihl_ver) >> 4)
  #define IP_IHL(ip_ihl_ver) ((ip_ihl_ver) & 15)
  #define IP_IHL_VER(ihl, ver) (((ver) << 4) | (ihl))
  
  #ifndef IPPROTO_SCTP
  #define IPPROTO_SCTP 132
  #endif
  
  #ifndef IPPROTO_DCCP
  #define IPPROTO_DCCP 33
  #endif
  
  #ifndef IPPROTO_IGMP
  #define IPPROTO_IGMP 2
  #endif
  
  #ifndef IPPROTO_UDPLITE
  #define IPPROTO_UDPLITE 136
  #endif
  
  /* TOS fields. */
  #define IP_ECN_NOT_ECT 0x0
  #define IP_ECN_ECT_1 0x01
  #define IP_ECN_ECT_0 0x02
  #define IP_ECN_CE 0x03
  #define IP_ECN_MASK 0x03
  #define IP_DSCP_CS6 0xc0
  #define IP_DSCP_MASK 0xfc
  
  static inline int
  IP_ECN_is_ce(uint8_t dsfield)
  {
      return (dsfield & IP_ECN_MASK) == IP_ECN_CE;
  }
  
  #define IP_VERSION 4
  
  #define IP_DONT_FRAGMENT  0x4000 /* Don't fragment. */
  #define IP_MORE_FRAGMENTS 0x2000 /* More fragments. */
  #define IP_FRAG_OFF_MASK  0x1fff /* Fragment offset. */
  #define IP_IS_FRAGMENT(ip_frag_off) \
          ((ip_frag_off) & htons(IP_MORE_FRAGMENTS | IP_FRAG_OFF_MASK))
  
  #define IP_HEADER_LEN 20
  struct ip_header {
      uint8_t ip_ihl_ver;
      uint8_t ip_tos;
      ovs_be16 ip_tot_len;
      ovs_be16 ip_id;
      ovs_be16 ip_frag_off;
      uint8_t ip_ttl;
      uint8_t ip_proto;
      ovs_be16 ip_csum;
      ovs_16aligned_be32 ip_src;
      ovs_16aligned_be32 ip_dst;
  };
  BUILD_ASSERT_DECL(IP_HEADER_LEN == sizeof(struct ip_header));
  
  /* ICMPv4 types. */
  #define ICMP4_ECHO_REPLY 0
  #define ICMP4_DST_UNREACH 3
  #define ICMP4_SOURCEQUENCH 4
  #define ICMP4_REDIRECT 5
  #define ICMP4_ECHO_REQUEST 8
  #define ICMP4_TIME_EXCEEDED 11
  #define ICMP4_PARAM_PROB 12
  #define ICMP4_TIMESTAMP 13
  #define ICMP4_TIMESTAMPREPLY 14
  #define ICMP4_INFOREQUEST 15
  #define ICMP4_INFOREPLY 16
  
  #define ICMP_HEADER_LEN 8
  struct icmp_header {
      uint8_t icmp_type;
      uint8_t icmp_code;
      ovs_be16 icmp_csum;
      union {
          struct {
              ovs_be16 id;
              ovs_be16 seq;
          } echo;
          struct {
              ovs_be16 empty;
              ovs_be16 mtu;
          } frag;
          ovs_16aligned_be32 gateway;
      } icmp_fields;
  };
  BUILD_ASSERT_DECL(ICMP_HEADER_LEN == sizeof(struct icmp_header));
  
  /* ICMPV4 */
  #define ICMP_ERROR_DATA_L4_LEN 8
  
  #define IGMP_HEADER_LEN 8
  struct igmp_header {
      uint8_t igmp_type;
      uint8_t igmp_code;
      ovs_be16 igmp_csum;
      ovs_16aligned_be32 group;
  };
  BUILD_ASSERT_DECL(IGMP_HEADER_LEN == sizeof(struct igmp_header));
  
  #define IGMPV3_HEADER_LEN 8
  struct igmpv3_header {
      uint8_t type;
      uint8_t rsvr1;
      ovs_be16 csum;
      ovs_be16 rsvr2;
      ovs_be16 ngrp;
  };
  BUILD_ASSERT_DECL(IGMPV3_HEADER_LEN == sizeof(struct igmpv3_header));
  
  #define IGMPV3_QUERY_HEADER_LEN 12
  struct igmpv3_query_header {
      uint8_t type;
      uint8_t max_resp;
      ovs_be16 csum;
      ovs_16aligned_be32 group;
      uint8_t srs_qrv;
      uint8_t qqic;
      ovs_be16 nsrcs;
  };
  BUILD_ASSERT_DECL(
      IGMPV3_QUERY_HEADER_LEN == sizeof(struct igmpv3_query_header
  ));
  
  #define IGMPV3_RECORD_LEN 8
  struct igmpv3_record {
      uint8_t type;
      uint8_t aux_len;
      ovs_be16 nsrcs;
      ovs_16aligned_be32 maddr;
  };
  BUILD_ASSERT_DECL(IGMPV3_RECORD_LEN == sizeof(struct igmpv3_record));
  
  #define IGMP_HOST_MEMBERSHIP_QUERY    0x11 /* From RFC1112 */
  #define IGMP_HOST_MEMBERSHIP_REPORT   0x12 /* Ditto */
  #define IGMPV2_HOST_MEMBERSHIP_REPORT 0x16 /* V2 version of 0x12 */
  #define IGMP_HOST_LEAVE_MESSAGE       0x17
  #define IGMPV3_HOST_MEMBERSHIP_REPORT 0x22 /* V3 version of 0x12 */
  
  /*
   * IGMPv3 and MLDv2 use the same codes.
   */
  #define IGMPV3_MODE_IS_INCLUDE 1
  #define IGMPV3_MODE_IS_EXCLUDE 2
  #define IGMPV3_CHANGE_TO_INCLUDE_MODE 3
  #define IGMPV3_CHANGE_TO_EXCLUDE_MODE 4
  #define IGMPV3_ALLOW_NEW_SOURCES 5
  #define IGMPV3_BLOCK_OLD_SOURCES 6
  
  #define SCTP_HEADER_LEN 12
  struct sctp_header {
      ovs_be16 sctp_src;
      ovs_be16 sctp_dst;
      ovs_16aligned_be32 sctp_vtag;
      ovs_16aligned_be32 sctp_csum;
  };
  BUILD_ASSERT_DECL(SCTP_HEADER_LEN == sizeof(struct sctp_header));
  
  #define UDP_HEADER_LEN 8
  struct udp_header {
      ovs_be16 udp_src;
      ovs_be16 udp_dst;
      ovs_be16 udp_len;
      ovs_be16 udp_csum;
  };
  BUILD_ASSERT_DECL(UDP_HEADER_LEN == sizeof(struct udp_header));
  
  #define ESP_HEADER_LEN 8
  struct esp_header {
      ovs_be32 spi;
      ovs_be32 seq_no;
  };
  BUILD_ASSERT_DECL(ESP_HEADER_LEN == sizeof(struct esp_header));
  
  #define ESP_TRAILER_LEN 2
  struct esp_trailer {
      uint8_t pad_len;
      uint8_t next_hdr;
  };
  BUILD_ASSERT_DECL(ESP_TRAILER_LEN == sizeof(struct esp_trailer));
  
  #define TCP_FIN 0x001
  #define TCP_SYN 0x002
  #define TCP_RST 0x004
  #define TCP_PSH 0x008
  #define TCP_ACK 0x010
  #define TCP_URG 0x020
  #define TCP_ECE 0x040
  #define TCP_CWR 0x080
  #define TCP_NS  0x100
  
  #define TCP_CTL(flags, offset) (htons((flags) | ((offset) << 12)))
  #define TCP_FLAGS(tcp_ctl) (ntohs(tcp_ctl) & 0x0fff)
  #define TCP_FLAGS_BE16(tcp_ctl) ((tcp_ctl) & htons(0x0fff))
  #define TCP_OFFSET(tcp_ctl) (ntohs(tcp_ctl) >> 12)
  
  #define TCP_HEADER_LEN 20
  struct tcp_header {
      ovs_be16 tcp_src;
      ovs_be16 tcp_dst;
      ovs_16aligned_be32 tcp_seq;
      ovs_16aligned_be32 tcp_ack;
      ovs_be16 tcp_ctl;
      ovs_be16 tcp_winsz;
      ovs_be16 tcp_csum;
      ovs_be16 tcp_urg;
  };
  BUILD_ASSERT_DECL(TCP_HEADER_LEN == sizeof(struct tcp_header));
  
  /* Connection states.
   *
   * Names like CS_RELATED are bit values, e.g. 1 << 2.
   * Names like CS_RELATED_BIT are bit indexes, e.g. 2. */
  #define CS_STATES                               \
      CS_STATE(NEW,         0, "new")             \
      CS_STATE(ESTABLISHED, 1, "est")             \
      CS_STATE(RELATED,     2, "rel")             \
      CS_STATE(REPLY_DIR,   3, "rpl")             \
      CS_STATE(INVALID,     4, "inv")             \
      CS_STATE(TRACKED,     5, "trk")             \
      CS_STATE(SRC_NAT,     6, "snat")            \
      CS_STATE(DST_NAT,     7, "dnat")
  
  enum {
  #define CS_STATE(ENUM, INDEX, NAME) \
      CS_##ENUM = 1 << INDEX, \
      CS_##ENUM##_BIT = INDEX,
      CS_STATES
  #undef CS_STATE
  };
  
  /* Undefined connection state bits. */
  enum {
  #define CS_STATE(ENUM, INDEX, NAME) +CS_##ENUM
      CS_SUPPORTED_MASK = CS_STATES
  #undef CS_STATE
  };
  #define CS_UNSUPPORTED_MASK  (~(uint32_t)CS_SUPPORTED_MASK)
  
  #define ARP_HRD_ETHERNET 1
  #define ARP_PRO_IP 0x0800
  #define ARP_OP_REQUEST 1
  #define ARP_OP_REPLY 2
  #define ARP_OP_RARP 3
  
  #define ARP_ETH_HEADER_LEN 28
  struct arp_eth_header {
      /* Generic members. */
      ovs_be16 ar_hrd;           /* Hardware type. */
      ovs_be16 ar_pro;           /* Protocol type. */
      uint8_t ar_hln;            /* Hardware address length. */
      uint8_t ar_pln;            /* Protocol address length. */
      ovs_be16 ar_op;            /* Opcode. */
  
      /* Ethernet+IPv4 specific members. */
      struct eth_addr ar_sha;     /* Sender hardware address. */
      ovs_16aligned_be32 ar_spa;  /* Sender protocol address. */
      struct eth_addr ar_tha;     /* Target hardware address. */
      ovs_16aligned_be32 ar_tpa;  /* Target protocol address. */
  };
  BUILD_ASSERT_DECL(ARP_ETH_HEADER_LEN == sizeof(struct arp_eth_header));
  
  #define IPV6_HEADER_LEN 40
  
  /* Like struct in6_addr, but whereas that struct requires 32-bit alignment on
   * most implementations, this one only requires 16-bit alignment. */
  union ovs_16aligned_in6_addr {
      ovs_be16 be16[8];
      ovs_16aligned_be32 be32[4];
  };
  
  /* Like struct in6_hdr, but whereas that struct requires 32-bit alignment, this
   * one only requires 16-bit alignment. */
  struct ovs_16aligned_ip6_hdr {
      union {
          struct ovs_16aligned_ip6_hdrctl {
              ovs_16aligned_be32 ip6_un1_flow;
              ovs_be16 ip6_un1_plen;
              uint8_t ip6_un1_nxt;
              uint8_t ip6_un1_hlim;
          } ip6_un1;
          uint8_t ip6_un2_vfc;
      } ip6_ctlun;
      union ovs_16aligned_in6_addr ip6_src;
      union ovs_16aligned_in6_addr ip6_dst;
  };
  
  /* Like struct in6_frag, but whereas that struct requires 32-bit alignment,
   * this one only requires 16-bit alignment. */
  struct ovs_16aligned_ip6_frag {
      uint8_t ip6f_nxt;
      uint8_t ip6f_reserved;
      ovs_be16 ip6f_offlg;
      ovs_16aligned_be32 ip6f_ident;
  };
  
  #define ICMP6_HEADER_LEN 4
  struct icmp6_header {
      uint8_t icmp6_type;
      uint8_t icmp6_code;
      ovs_be16 icmp6_cksum;
  };
  BUILD_ASSERT_DECL(ICMP6_HEADER_LEN == sizeof(struct icmp6_header));
  
  #define ICMP6_DATA_HEADER_LEN 8
  struct icmp6_data_header {
      struct icmp6_header icmp6_base;
      union {
          ovs_16aligned_be32 be32[1];
          ovs_be16           be16[2];
          uint8_t            u8[4];
      } icmp6_data;
  };
  BUILD_ASSERT_DECL(ICMP6_DATA_HEADER_LEN == sizeof(struct icmp6_data_header));
  
  uint32_t packet_csum_pseudoheader6(const struct ovs_16aligned_ip6_hdr *);
  ovs_be16 packet_csum_upperlayer6(const struct ovs_16aligned_ip6_hdr *,
                                   const void *, uint8_t, uint16_t);
  
  /* Neighbor Discovery option field.
   * ND options are always a multiple of 8 bytes in size. */
  #define ND_LLA_OPT_LEN 8
  struct ovs_nd_lla_opt {
      uint8_t type;               /* One of ND_OPT_*_LINKADDR. */
      uint8_t len;
      struct eth_addr mac;
  };
  BUILD_ASSERT_DECL(ND_LLA_OPT_LEN == sizeof(struct ovs_nd_lla_opt));
  
  /* Neighbor Discovery option: Prefix Information. */
  #define ND_PREFIX_OPT_LEN 32
  struct ovs_nd_prefix_opt {
      uint8_t type;               /* ND_OPT_PREFIX_INFORMATION. */
      uint8_t len;                /* Always 4. */
      uint8_t prefix_len;
      uint8_t la_flags;           /* ND_PREFIX_* flags. */
      ovs_16aligned_be32 valid_lifetime;
      ovs_16aligned_be32 preferred_lifetime;
      ovs_16aligned_be32 reserved;          /* Always 0. */
      union ovs_16aligned_in6_addr prefix;
  };
  BUILD_ASSERT_DECL(ND_PREFIX_OPT_LEN == sizeof(struct ovs_nd_prefix_opt));
  
  /* Neighbor Discovery option: MTU. */
  #define ND_MTU_OPT_LEN 8
  #define ND_MTU_DEFAULT 0
  struct ovs_nd_mtu_opt {
      uint8_t  type;      /* ND_OPT_MTU */
      uint8_t  len;       /* Always 1. */
      ovs_be16 reserved;  /* Always 0. */
      ovs_16aligned_be32 mtu;
  };
  BUILD_ASSERT_DECL(ND_MTU_OPT_LEN == sizeof(struct ovs_nd_mtu_opt));
  
  /* Like struct nd_msg (from ndisc.h), but whereas that struct requires 32-bit
   * alignment, this one only requires 16-bit alignment. */
  #define ND_MSG_LEN 24
  struct ovs_nd_msg {
      struct icmp6_header icmph;
      ovs_16aligned_be32 rso_flags;
      union ovs_16aligned_in6_addr target;
      struct ovs_nd_lla_opt options[0];
  };
  BUILD_ASSERT_DECL(ND_MSG_LEN == sizeof(struct ovs_nd_msg));
  
  /* Neighbor Discovery packet flags. */
  #define ND_RSO_ROUTER    0x80000000
  #define ND_RSO_SOLICITED 0x40000000
  #define ND_RSO_OVERRIDE  0x20000000
  
  #define RA_MSG_LEN 16
  struct ovs_ra_msg {
      struct icmp6_header icmph;
      uint8_t cur_hop_limit;
      uint8_t mo_flags;  /* ND_RA_MANAGED_ADDRESS and ND_RA_OTHER_CONFIG flags. */
      ovs_be16 router_lifetime;
      ovs_be32 reachable_time;
      ovs_be32 retrans_timer;
      struct ovs_nd_lla_opt options[0];
  };
  BUILD_ASSERT_DECL(RA_MSG_LEN == sizeof(struct ovs_ra_msg));
  
  #define ND_RA_MANAGED_ADDRESS 0x80
  #define ND_RA_OTHER_CONFIG    0x40
  
  /* Defaults based on MaxRtrInterval and MinRtrInterval from RFC 4861 section
   * 6.2.1
   */
  #define ND_RA_MAX_INTERVAL_DEFAULT 600
  
  static inline int
  nd_ra_min_interval_default(int max)
  {
      return max >= 9 ? max / 3 : max * 3 / 4;
  }
  
  /*
   * Use the same struct for MLD and MLD2, naming members as the defined fields in
   * in the corresponding version of the protocol, though they are reserved in the
   * other one.
   */
  #define MLD_HEADER_LEN 8
  struct mld_header {
      uint8_t type;
      uint8_t code;
      ovs_be16 csum;
      ovs_be16 mrd;
      ovs_be16 ngrp;
  };
  BUILD_ASSERT_DECL(MLD_HEADER_LEN == sizeof(struct mld_header));
  
  #define MLD2_RECORD_LEN 20
  struct mld2_record {
      uint8_t type;
      uint8_t aux_len;
      ovs_be16 nsrcs;
      union ovs_16aligned_in6_addr maddr;
  };
  BUILD_ASSERT_DECL(MLD2_RECORD_LEN == sizeof(struct mld2_record));
  
  #define MLD_QUERY 130
  #define MLD_REPORT 131
  #define MLD_DONE 132
  #define MLD2_REPORT 143
  
  /* The IPv6 flow label is in the lower 20 bits of the first 32-bit word. */
  #define IPV6_LABEL_MASK 0x000fffff
  
  /* Example:
   *
   * char *string = "1 ::1 2";
   * char ipv6_s[IPV6_SCAN_LEN + 1];
   * struct in6_addr ipv6;
   *
   * if (ovs_scan(string, "%d"IPV6_SCAN_FMT"%d", &a, ipv6_s, &b)
   *     && inet_pton(AF_INET6, ipv6_s, &ipv6) == 1) {
   *     ...
   * }
   */
  #define IPV6_SCAN_FMT "%46[0123456789abcdefABCDEF:.]"
  #define IPV6_SCAN_LEN 46
  
  extern const struct in6_addr in6addr_exact;
  #define IN6ADDR_EXACT_INIT { { { 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, \
                                   0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff } } }
  
  extern const struct in6_addr in6addr_all_hosts;
  #define IN6ADDR_ALL_HOSTS_INIT { { { 0xff,0x02,0x00,0x00,0x00,0x00,0x00,0x00, \
                                       0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01 } } }
  
  extern const struct in6_addr in6addr_all_routers;
  #define IN6ADDR_ALL_ROUTERS_INIT { { { 0xff,0x02,0x00,0x00,0x00,0x00,0x00,0x00, \
                                         0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x02 } } }
  
  static inline bool ipv6_addr_equals(const struct in6_addr *a,
                                      const struct in6_addr *b)
  {
  #ifdef IN6_ARE_ADDR_EQUAL
      return IN6_ARE_ADDR_EQUAL(a, b);
  #else
      return !memcmp(a, b, sizeof(*a));
  #endif
  }
  
  /* Checks the IPv6 address in 'mask' for all zeroes. */
  static inline bool ipv6_mask_is_any(const struct in6_addr *mask) {
      return ipv6_addr_equals(mask, &in6addr_any);
  }
  
  static inline bool ipv6_mask_is_exact(const struct in6_addr *mask) {
      return ipv6_addr_equals(mask, &in6addr_exact);
  }
  
  static inline bool ipv6_is_all_hosts(const struct in6_addr *addr) {
      return ipv6_addr_equals(addr, &in6addr_all_hosts);
  }
  
  static inline bool ipv6_addr_is_set(const struct in6_addr *addr) {
      return !ipv6_addr_equals(addr, &in6addr_any);
  }
  
  static inline bool ipv6_addr_is_multicast(const struct in6_addr *ip) {
      return ip->s6_addr[0] == 0xff;
  }
  
  static inline struct in6_addr
  in6_addr_mapped_ipv4(ovs_be32 ip4)
  {
      struct in6_addr ip6;
      memset(&ip6, 0, sizeof(ip6));
      ip6.s6_addr[10] = 0xff, ip6.s6_addr[11] = 0xff;
      memcpy(&ip6.s6_addr[12], &ip4, 4);
      return ip6;
  }
  
  static inline void
  in6_addr_set_mapped_ipv4(struct in6_addr *ip6, ovs_be32 ip4)
  {
      *ip6 = in6_addr_mapped_ipv4(ip4);
  }
  
  static inline ovs_be32
  in6_addr_get_mapped_ipv4(const struct in6_addr *addr)
  {
      union ovs_16aligned_in6_addr *taddr =
          (union ovs_16aligned_in6_addr *) addr;
      if (IN6_IS_ADDR_V4MAPPED(addr)) {
          return get_16aligned_be32(&taddr->be32[3]);
      } else {
          return INADDR_ANY;
      }
  }
  
  static inline void
  in6_addr_solicited_node(struct in6_addr *addr, const struct in6_addr *ip6)
  {
      union ovs_16aligned_in6_addr *taddr =
          (union ovs_16aligned_in6_addr *) addr;
      memset(taddr->be16, 0, sizeof(taddr->be16));
      taddr->be16[0] = htons(0xff02);
      taddr->be16[5] = htons(0x1);
      taddr->be16[6] = htons(0xff00);
      memcpy(&addr->s6_addr[13], &ip6->s6_addr[13], 3);
  }
  
  /*
   * Generates ipv6 EUI64 address from the given eth addr
   * and prefix and stores it in 'lla'
   */
  static inline void
  in6_generate_eui64(struct eth_addr ea, struct in6_addr *prefix,
                     struct in6_addr *lla)
  {
      union ovs_16aligned_in6_addr *taddr =
          (union ovs_16aligned_in6_addr *) lla;
      union ovs_16aligned_in6_addr *prefix_taddr =
          (union ovs_16aligned_in6_addr *) prefix;
      taddr->be16[0] = prefix_taddr->be16[0];
      taddr->be16[1] = prefix_taddr->be16[1];
      taddr->be16[2] = prefix_taddr->be16[2];
      taddr->be16[3] = prefix_taddr->be16[3];
      taddr->be16[4] = htons(((ea.ea[0] ^ 0x02) << 8) | ea.ea[1]);
      taddr->be16[5] = htons(ea.ea[2] << 8 | 0x00ff);
      taddr->be16[6] = htons(0xfe << 8 | ea.ea[3]);
      taddr->be16[7] = ea.be16[2];
  }
  
  /*
   * Generates ipv6 link local address from the given eth addr
   * with prefix 'fe80::/64' and stores it in 'lla'
   */
  static inline void
  in6_generate_lla(struct eth_addr ea, struct in6_addr *lla)
  {
      union ovs_16aligned_in6_addr *taddr =
          (union ovs_16aligned_in6_addr *) lla;
      memset(taddr->be16, 0, sizeof(taddr->be16));
      taddr->be16[0] = htons(0xfe80);
      taddr->be16[4] = htons(((ea.ea[0] ^ 0x02) << 8) | ea.ea[1]);
      taddr->be16[5] = htons(ea.ea[2] << 8 | 0x00ff);
      taddr->be16[6] = htons(0xfe << 8 | ea.ea[3]);
      taddr->be16[7] = ea.be16[2];
  }
  
  /* Returns true if 'addr' is a link local address.  Otherwise, false. */
  static inline bool
  in6_is_lla(struct in6_addr *addr)
  {
  #ifdef s6_addr32
      return addr->s6_addr32[0] == htonl(0xfe800000) && !(addr->s6_addr32[1]);
  #else
      return addr->s6_addr[0] == 0xfe && addr->s6_addr[1] == 0x80 &&
           !(addr->s6_addr[2] | addr->s6_addr[3] | addr->s6_addr[4] |
             addr->s6_addr[5] | addr->s6_addr[6] | addr->s6_addr[7]);
  #endif
  }
  
  static inline void
  ipv6_multicast_to_ethernet(struct eth_addr *eth, const struct in6_addr *ip6)
  {
      eth->ea[0] = 0x33;
      eth->ea[1] = 0x33;
      eth->ea[2] = ip6->s6_addr[12];
      eth->ea[3] = ip6->s6_addr[13];
      eth->ea[4] = ip6->s6_addr[14];
      eth->ea[5] = ip6->s6_addr[15];
  }
  
  static inline bool dl_type_is_ip_any(ovs_be16 dl_type)
  {
      return dl_type == htons(ETH_TYPE_IP)
          || dl_type == htons(ETH_TYPE_IPV6);
  }
  
  /* Tunnel header */
  
  /* GRE protocol header */
  struct gre_base_hdr {
      ovs_be16 flags;
      ovs_be16 protocol;
  };
  
  #define GRE_CSUM        0x8000
  #define GRE_ROUTING     0x4000
  #define GRE_KEY         0x2000
  #define GRE_SEQ         0x1000
  #define GRE_STRICT      0x0800
  #define GRE_REC         0x0700
  #define GRE_FLAGS       0x00F8
  #define GRE_VERSION     0x0007
  
  /*
   * ERSPAN protocol header and metadata
   *
   * Version 1 (Type II) header (8 octets [42:49])
   *  0                   1                   2                   3
   *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |  Ver  |          VLAN         | COS | En|T|    Session ID     |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |      Reserved         |                  Index                |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   *
   *  ERSPAN Version 2 (Type III) header (12 octets [42:49])
   *  0                   1                   2                   3
   *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |  Ver  |          VLAN         | COS |BSO|T|     Session ID    |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                          Timestamp                            |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |             SGT               |P|    FT   |   Hw ID   |D|Gra|O|
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   */
  
  /* ERSPAN has fixed 8-byte GRE header */
  #define ERSPAN_GREHDR_LEN   8
  #define ERSPAN_HDR(gre_base_hdr) \
      ((struct erspan_base_hdr *)((char *)gre_base_hdr + ERSPAN_GREHDR_LEN))
  
  #define ERSPAN_V1_MDSIZE    4
  #define ERSPAN_V2_MDSIZE    8
  
  #define ERSPAN_SID_MASK     0x03ff  /* 10-bit Session ID. */
  #define ERSPAN_IDX_MASK     0xfffff /* v1 Index */
  #define ERSPAN_HWID_MASK    0x03f0
  #define ERSPAN_DIR_MASK     0x0008
  
  struct erspan_base_hdr {
  #ifdef WORDS_BIGENDIAN
      uint8_t ver:4,
              vlan_upper:4;
      uint8_t vlan:8;
      uint8_t cos:3,
              en:2,
              t:1,
              session_id_upper:2;
      uint8_t session_id:8;
  #else
      uint8_t vlan_upper:4,
              ver:4;
      uint8_t vlan:8;
      uint8_t session_id_upper:2,
              t:1,
              en:2,
              cos:3;
      uint8_t session_id:8;
  #endif
  };
  
  struct erspan_md2 {
      ovs_16aligned_be32 timestamp;
      ovs_be16 sgt;
  #ifdef WORDS_BIGENDIAN
      uint8_t p:1,
              ft:5,
              hwid_upper:2;
      uint8_t hwid:4,
              dir:1,
              gra:2,
              o:1;
  #else
      uint8_t hwid_upper:2,
              ft:5,
              p:1;
      uint8_t o:1,
              gra:2,
              dir:1,
              hwid:4;
  #endif
  };
  
  struct erspan_metadata {
      int version;
      union {
          ovs_be32 index;         /* Version 1 (type II)*/
          struct erspan_md2 md2;  /* Version 2 (type III) */
      } u;
  };
  
  static inline uint16_t get_sid(const struct erspan_base_hdr *ershdr)
  {
      return (ershdr->session_id_upper << 8) + ershdr->session_id;
  }
  
  static inline void set_sid(struct erspan_base_hdr *ershdr, uint16_t id)
  {
      ershdr->session_id = id & 0xff;
      ershdr->session_id_upper = (id >> 8) &0x3;
  }
  
  static inline uint8_t get_hwid(const struct erspan_md2 *md2)
  {
      return (md2->hwid_upper << 4) + md2->hwid;
  }
  
  static inline void set_hwid(struct erspan_md2 *md2, uint8_t hwid)
  {
      md2->hwid = hwid & 0xf;
      md2->hwid_upper = (hwid >> 4) & 0x3;
  }
  
  /* ERSPAN timestamp granularity
   *   00b --> granularity = 100 microseconds
   *   01b --> granularity = 100 nanoseconds
   *   10b --> granularity = IEEE 1588
   * Here we only support 100 microseconds.
   */
  enum erspan_ts_gra {
      ERSPAN_100US,
      ERSPAN_100NS,
      ERSPAN_IEEE1588,
  };
  
  static inline ovs_be32 get_erspan_ts(enum erspan_ts_gra gra)
  {
      ovs_be32 ts = 0;
  
      switch (gra) {
      case ERSPAN_100US:
          ts = htonl((uint32_t)(time_wall_usec() / 100));
          break;
      case ERSPAN_100NS:
          /* fall back */
      case ERSPAN_IEEE1588:
          /* fall back */
      default:
          OVS_NOT_REACHED();
          break;
      }
      return ts;
  }
  
  /* VXLAN protocol header */
  struct vxlanhdr {
      union {
          ovs_16aligned_be32 vx_flags; /* VXLAN flags. */
          struct {
              uint8_t flags;           /* VXLAN GPE flags. */
              uint8_t reserved[2];     /* 16 bits reserved. */
              uint8_t next_protocol;   /* Next Protocol field for VXLAN GPE. */
          } vx_gpe;
      };
      ovs_16aligned_be32 vx_vni;
  };
  BUILD_ASSERT_DECL(sizeof(struct vxlanhdr) == 8);
  
  #define VXLAN_FLAGS 0x08000000  /* struct vxlanhdr.vx_flags required value. */
  
  /*
   * VXLAN Generic Protocol Extension (VXLAN_F_GPE):
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |R|R|Ver|I|P|R|O|       Reserved                |Next Protocol  |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                VXLAN Network Identifier (VNI) |   Reserved    |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   * Ver = Version. Indicates VXLAN GPE protocol version.
   *
   * P = Next Protocol Bit. The P bit is set to indicate that the
   *     Next Protocol field is present.
   *
   * O = OAM Flag Bit. The O bit is set to indicate that the packet
   *     is an OAM packet.
   *
   * Next Protocol = This 8 bit field indicates the protocol header
   * immediately following the VXLAN GPE header.
   *
   * https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-01
   */
  
  /* Fields in struct vxlanhdr.vx_gpe.flags */
  #define VXLAN_GPE_FLAGS_VER     0x30    /* Version. */
  #define VLXAN_GPE_FLAGS_P       0x04    /* Next Protocol Bit. */
  #define VXLAN_GPE_FLAGS_O       0x01    /* OAM Bit. */
  
  /* VXLAN-GPE header flags. */
  #define VXLAN_HF_VER   ((1U <<29) | (1U <<28))
  #define VXLAN_HF_NP    (1U <<26)
  #define VXLAN_HF_OAM   (1U <<24)
  
  #define VXLAN_GPE_USED_BITS (VXLAN_HF_VER | VXLAN_HF_NP | VXLAN_HF_OAM | \
                              0xff)
  
  /* VXLAN-GPE header Next Protocol. */
  #define VXLAN_GPE_NP_IPV4      0x01
  #define VXLAN_GPE_NP_IPV6      0x02
  #define VXLAN_GPE_NP_ETHERNET  0x03
  #define VXLAN_GPE_NP_NSH       0x04
  
  #define VXLAN_F_GPE  0x4000
  #define VXLAN_HF_GPE 0x04000000
  
  /* Input values for PACKET_TYPE macros have to be in host byte order.
   * The _BE postfix indicates result is in network byte order. Otherwise result
   * is in host byte order. */
  #define PACKET_TYPE(NS, NS_TYPE) ((uint32_t) ((NS) << 16 | (NS_TYPE)))
  #define PACKET_TYPE_BE(NS, NS_TYPE) (htonl((NS) << 16 | (NS_TYPE)))
  
  /* Returns the host byte ordered namespace of 'packet type'. */
  static inline uint16_t
  pt_ns(ovs_be32 packet_type)
  {
      return ntohl(packet_type) >> 16;
  }
  
  /* Returns the network byte ordered namespace type of 'packet type'. */
  static inline ovs_be16
  pt_ns_type_be(ovs_be32 packet_type)
  {
      return be32_to_be16(packet_type);
  }
  
  /* Returns the host byte ordered namespace type of 'packet type'. */
  static inline uint16_t
  pt_ns_type(ovs_be32 packet_type)
  {
      return ntohs(pt_ns_type_be(packet_type));
  }
  
  /* Well-known packet_type field values. */
  enum packet_type {
      PT_ETH  = PACKET_TYPE(OFPHTN_ONF, 0x0000),  /* Default PT: Ethernet */
      PT_USE_NEXT_PROTO = PACKET_TYPE(OFPHTN_ONF, 0xfffe),  /* Pseudo PT for decap. */
      PT_IPV4 = PACKET_TYPE(OFPHTN_ETHERTYPE, ETH_TYPE_IP),
      PT_IPV6 = PACKET_TYPE(OFPHTN_ETHERTYPE, ETH_TYPE_IPV6),
      PT_MPLS = PACKET_TYPE(OFPHTN_ETHERTYPE, ETH_TYPE_MPLS),
      PT_MPLS_MC = PACKET_TYPE(OFPHTN_ETHERTYPE, ETH_TYPE_MPLS_MCAST),
      PT_NSH  = PACKET_TYPE(OFPHTN_ETHERTYPE, ETH_TYPE_NSH),
      PT_UNKNOWN = PACKET_TYPE(0xffff, 0xffff),   /* Unknown packet type. */
  };
  
  
  void ipv6_format_addr(const struct in6_addr *addr, struct ds *);
  void ipv6_format_addr_bracket(const struct in6_addr *addr, struct ds *,
                                bool bracket);
  void ipv6_format_mapped(const struct in6_addr *addr, struct ds *);
  void ipv6_format_masked(const struct in6_addr *addr,
                          const struct in6_addr *mask, struct ds *);
  const char * ipv6_string_mapped(char *addr_str, const struct in6_addr *addr);
  struct in6_addr ipv6_addr_bitand(const struct in6_addr *src,
                                   const struct in6_addr *mask);
  struct in6_addr ipv6_addr_bitxor(const struct in6_addr *a,
                                   const struct in6_addr *b);
  bool ipv6_is_zero(const struct in6_addr *a);
  struct in6_addr ipv6_create_mask(int mask);
  int ipv6_count_cidr_bits(const struct in6_addr *netmask);
  bool ipv6_is_cidr(const struct in6_addr *netmask);
  
  bool ipv6_parse(const char *s, struct in6_addr *ip);
  char *ipv6_parse_masked(const char *s, struct in6_addr *ipv6,
                          struct in6_addr *mask);
  char *ipv6_parse_cidr(const char *s, struct in6_addr *ip, unsigned int *plen)
      OVS_WARN_UNUSED_RESULT;
  char *ipv6_parse_masked_len(const char *s, int *n, struct in6_addr *ipv6,
                              struct in6_addr *mask);
  char *ipv6_parse_cidr_len(const char *s, int *n, struct in6_addr *ip,
                            unsigned int *plen)
      OVS_WARN_UNUSED_RESULT;
  
  void *eth_compose(struct dp_packet *, const struct eth_addr eth_dst,
                    const struct eth_addr eth_src, uint16_t eth_type,
                    size_t size);
  void *snap_compose(struct dp_packet *, const struct eth_addr eth_dst,
                     const struct eth_addr eth_src,
                     unsigned int oui, uint16_t snap_type, size_t size);
  void packet_set_ipv4(struct dp_packet *, ovs_be32 src, ovs_be32 dst, uint8_t tos,
                       uint8_t ttl);
  void packet_set_ipv4_addr(struct dp_packet *packet, ovs_16aligned_be32 *addr,
                            ovs_be32 new_addr);
  void packet_set_ipv6(struct dp_packet *, const struct in6_addr *src,
                       const struct in6_addr *dst, uint8_t tc,
                       ovs_be32 fl, uint8_t hlmit);
  void packet_set_ipv6_addr(struct dp_packet *packet, uint8_t proto,
                            ovs_16aligned_be32 addr[4],
                            const struct in6_addr *new_addr,
                            bool recalculate_csum);
  void packet_set_tcp_port(struct dp_packet *, ovs_be16 src, ovs_be16 dst);
  void packet_set_udp_port(struct dp_packet *, ovs_be16 src, ovs_be16 dst);
  void packet_set_sctp_port(struct dp_packet *, ovs_be16 src, ovs_be16 dst);
  void packet_set_icmp(struct dp_packet *, uint8_t type, uint8_t code);
  void packet_set_nd(struct dp_packet *, const struct in6_addr *target,
                     const struct eth_addr sll, const struct eth_addr tll);
  void packet_set_nd_ext(struct dp_packet *packet,
                         const ovs_16aligned_be32 rso_flags,
                         const uint8_t opt_type);
  void packet_set_igmp3_query(struct dp_packet *, uint8_t max_resp,
                              ovs_be32 group, bool srs, uint8_t qrv,
                              uint8_t qqic);
  void packet_format_tcp_flags(struct ds *, uint16_t);
  const char *packet_tcp_flag_to_string(uint32_t flag);
  void *compose_ipv6(struct dp_packet *packet, uint8_t proto,
                     const struct in6_addr *src, const struct in6_addr *dst,
                     uint8_t key_tc, ovs_be32 key_fl, uint8_t key_hl, int size);
  void compose_arp__(struct dp_packet *);
  void compose_arp(struct dp_packet *, uint16_t arp_op,
                   const struct eth_addr arp_sha,
                   const struct eth_addr arp_tha, bool broadcast,
                   ovs_be32 arp_spa, ovs_be32 arp_tpa);
  void compose_nd_ns(struct dp_packet *, const struct eth_addr eth_src,
                     const struct in6_addr *ipv6_src,
                     const struct in6_addr *ipv6_dst);
  void compose_nd_na(struct dp_packet *, const struct eth_addr eth_src,
                     const struct eth_addr eth_dst,
                     const struct in6_addr *ipv6_src,
                     const struct in6_addr *ipv6_dst,
                     ovs_be32 rso_flags);
  void compose_nd_ra(struct dp_packet *,
                     const struct eth_addr eth_src,
                     const struct eth_addr eth_dst,
                     const struct in6_addr *ipv6_src,
                     const struct in6_addr *ipv6_dst,
                     uint8_t cur_hop_limit, uint8_t mo_flags,
                     ovs_be16 router_lt, ovs_be32 reachable_time,
                     ovs_be32 retrans_timer, uint32_t mtu);
  void packet_put_ra_prefix_opt(struct dp_packet *,
                                uint8_t plen, uint8_t la_flags,
                                ovs_be32 valid_lifetime,
                                ovs_be32 preferred_lifetime,
                                const ovs_be128 router_prefix);
  uint32_t packet_csum_pseudoheader(const struct ip_header *);
  void IP_ECN_set_ce(struct dp_packet *pkt, bool is_ipv6);
  
  #define DNS_HEADER_LEN 12
  struct dns_header {
      ovs_be16 id;
      uint8_t lo_flag; /* QR (1), OPCODE (4), AA (1), TC (1) and RD (1) */
      uint8_t hi_flag; /* RA (1), Z (3) and RCODE (4) */
      ovs_be16 qdcount; /* Num of entries in the question section. */
      ovs_be16 ancount; /* Num of resource records in the answer section. */
  
      /* Num of name server records in the authority record section. */
      ovs_be16 nscount;
  
      /* Num of resource records in the additional records section. */
      ovs_be16 arcount;
  };
  
  BUILD_ASSERT_DECL(DNS_HEADER_LEN == sizeof(struct dns_header));
  
  #define DNS_QUERY_TYPE_A        0x01
  #define DNS_QUERY_TYPE_AAAA     0x1c
  #define DNS_QUERY_TYPE_ANY      0xff
  
  #define DNS_CLASS_IN            0x01
  #define DNS_DEFAULT_RR_TTL      3600
  
  bool xdpnsh(uint32_t prob);
  
  #endif /* packets.h */
  