ovs/lib/flow.h

/*
 * 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.
 */
#ifndef FLOW_H
#define FLOW_H 1

#include <sys/types.h>
#include <netinet/in.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include "byte-order.h"
#include "openflow/nicira-ext.h"
#include "openflow/openflow.h"
#include "packets.h"
#include "hash.h"
#include "util.h"

struct dpif_flow_stats;
struct ds;
struct flow_wildcards;
struct minimask;
struct ofpbuf;
struct pkt_metadata;

/* This sequence number should be incremented whenever anything involving flows
 * or the wildcarding of flows changes.  This will cause build assertion
 * failures in places which likely need to be updated. */
#define FLOW_WC_SEQ 26

#define FLOW_N_REGS 8
BUILD_ASSERT_DECL(FLOW_N_REGS <= NXM_NX_MAX_REGS);

/* Used for struct flow's dl_type member for frames that have no Ethernet
 * type, that is, pure 802.2 frames. */
#define FLOW_DL_TYPE_NONE 0x5ff

/* Fragment bits, used for IPv4 and IPv6, always zero for non-IP flows. */
#define FLOW_NW_FRAG_ANY   (1 << 0) /* Set for any IP frag. */
#define FLOW_NW_FRAG_LATER (1 << 1) /* Set for IP frag with nonzero offset. */
#define FLOW_NW_FRAG_MASK  (FLOW_NW_FRAG_ANY | FLOW_NW_FRAG_LATER)

BUILD_ASSERT_DECL(FLOW_NW_FRAG_ANY == NX_IP_FRAG_ANY);
BUILD_ASSERT_DECL(FLOW_NW_FRAG_LATER == NX_IP_FRAG_LATER);

#define FLOW_TNL_F_DONT_FRAGMENT (1 << 0)
#define FLOW_TNL_F_CSUM (1 << 1)
#define FLOW_TNL_F_KEY (1 << 2)

const char *flow_tun_flag_to_string(uint32_t flags);

/* Maximum number of supported MPLS labels. */
#define FLOW_MAX_MPLS_LABELS 3

/*
 * A flow in the network.
 *
 * Must be initialized to all zeros to make any compiler-induced padding
 * zeroed.  Helps also in keeping unused fields (such as mutually exclusive
 * IPv4 and IPv6 addresses) zeroed out.
 *
 * The meaning of 'in_port' is context-dependent.  In most cases, it is a
 * 16-bit OpenFlow 1.0 port number.  In the software datapath interface (dpif)
 * layer and its implementations (e.g. dpif-linux, dpif-netdev), it is instead
 * a 32-bit datapath port number.
 *
 * The fields are organized in four segments to facilitate staged lookup, where
 * lower layer fields are first used to determine if the later fields need to
 * be looked at.  This enables better wildcarding for datapath flows.
 *
 * NOTE: Order of the fields is significant, any change in the order must be
 * reflected in miniflow_extract()!
 */
struct flow {
    /* L1 */
    struct flow_tnl tunnel;     /* Encapsulating tunnel parameters. */
    ovs_be64 metadata;          /* OpenFlow Metadata. */
    uint32_t regs[FLOW_N_REGS]; /* Registers. */
    uint32_t skb_priority;      /* Packet priority for QoS. */
    uint32_t pkt_mark;          /* Packet mark. */
    uint32_t recirc_id;         /* Must be exact match. */
    union flow_in_port in_port; /* Input port.*/

    /* L2, Order the same as in the Ethernet header! */
    uint8_t dl_dst[6];          /* Ethernet destination address. */
    uint8_t dl_src[6];          /* Ethernet source address. */
    ovs_be16 dl_type;           /* Ethernet frame type. */
    ovs_be16 vlan_tci;          /* If 802.1Q, TCI | VLAN_CFI; otherwise 0. */
    ovs_be32 mpls_lse[FLOW_MAX_MPLS_LABELS]; /* MPLS label stack entry. */

    /* L3 */
    struct in6_addr ipv6_src;   /* IPv6 source address. */
    struct in6_addr ipv6_dst;   /* IPv6 destination address. */
    ovs_be32 ipv6_label;        /* IPv6 flow label. */
    ovs_be32 nw_src;            /* IPv4 source address. */
    ovs_be32 nw_dst;            /* IPv4 destination address. */
    uint8_t nw_frag;            /* FLOW_FRAG_* flags. */
    uint8_t nw_tos;             /* IP ToS (including DSCP and ECN). */
    uint8_t nw_ttl;             /* IP TTL/Hop Limit. */
    uint8_t nw_proto;           /* IP protocol or low 8 bits of ARP opcode. */
    uint8_t arp_sha[6];         /* ARP/ND source hardware address. */
    uint8_t arp_tha[6];         /* ARP/ND target hardware address. */
    struct in6_addr nd_target;  /* IPv6 neighbor discovery (ND) target. */
    ovs_be16 tcp_flags;         /* TCP flags. With L3 to avoid matching L4. */
    ovs_be16 pad;               /* Padding. */

    /* L4 */
    ovs_be16 tp_src;            /* TCP/UDP/SCTP source port. */
    ovs_be16 tp_dst;            /* TCP/UDP/SCTP destination port.
                                 * Keep last for the BUILD_ASSERT_DECL below */
    uint32_t dp_hash;           /* Datapath computed hash value. The exact
                                   computation is opaque to the user space.*/
};
BUILD_ASSERT_DECL(sizeof(struct flow) % 4 == 0);

#define FLOW_U32S (sizeof(struct flow) / 4)

/* Remember to update FLOW_WC_SEQ when changing 'struct flow'. */
BUILD_ASSERT_DECL(offsetof(struct flow, dp_hash) + sizeof(uint32_t)
                  == sizeof(struct flow_tnl) + 172
                  && FLOW_WC_SEQ == 26);

/* Incremental points at which flow classification may be performed in
 * segments.
 * This is located here since this is dependent on the structure of the
 * struct flow defined above:
 * Each offset must be on a distinct, successive U32 boundary strictly
 * within the struct flow. */
enum {
    FLOW_SEGMENT_1_ENDS_AT = offsetof(struct flow, dl_dst),
    FLOW_SEGMENT_2_ENDS_AT = offsetof(struct flow, ipv6_src),
    FLOW_SEGMENT_3_ENDS_AT = offsetof(struct flow, tp_src),
};
BUILD_ASSERT_DECL(FLOW_SEGMENT_1_ENDS_AT % 4 == 0);
BUILD_ASSERT_DECL(FLOW_SEGMENT_2_ENDS_AT % 4 == 0);
BUILD_ASSERT_DECL(FLOW_SEGMENT_3_ENDS_AT % 4 == 0);
BUILD_ASSERT_DECL(                     0 < FLOW_SEGMENT_1_ENDS_AT);
BUILD_ASSERT_DECL(FLOW_SEGMENT_1_ENDS_AT < FLOW_SEGMENT_2_ENDS_AT);
BUILD_ASSERT_DECL(FLOW_SEGMENT_2_ENDS_AT < FLOW_SEGMENT_3_ENDS_AT);
BUILD_ASSERT_DECL(FLOW_SEGMENT_3_ENDS_AT < sizeof(struct flow));

extern const uint8_t flow_segment_u32s[];

/* Represents the metadata fields of struct flow. */
struct flow_metadata {
    uint32_t dp_hash;                /* Datapath computed hash field. */
    uint32_t recirc_id;              /* Recirculation ID. */
    ovs_be64 tun_id;                 /* Encapsulating tunnel ID. */
    ovs_be32 tun_src;                /* Tunnel outer IPv4 src addr */
    ovs_be32 tun_dst;                /* Tunnel outer IPv4 dst addr */
    ovs_be64 metadata;               /* OpenFlow 1.1+ metadata field. */
    uint32_t regs[FLOW_N_REGS];      /* Registers. */
    uint32_t pkt_mark;               /* Packet mark. */
    ofp_port_t in_port;              /* OpenFlow port or zero. */
};

void flow_extract(struct ofpbuf *, const struct pkt_metadata *md,
                  struct flow *);

void flow_zero_wildcards(struct flow *, const struct flow_wildcards *);
void flow_unwildcard_tp_ports(const struct flow *, struct flow_wildcards *);
void flow_get_metadata(const struct flow *, struct flow_metadata *);

char *flow_to_string(const struct flow *);
void format_flags(struct ds *ds, const char *(*bit_to_string)(uint32_t),
                  uint32_t flags, char del);
void format_flags_masked(struct ds *ds, const char *name,
                         const char *(*bit_to_string)(uint32_t),
                         uint32_t flags, uint32_t mask);

void flow_format(struct ds *, const struct flow *);
void flow_print(FILE *, const struct flow *);
static inline int flow_compare_3way(const struct flow *, const struct flow *);
static inline bool flow_equal(const struct flow *, const struct flow *);
static inline size_t flow_hash(const struct flow *, uint32_t basis);

void flow_set_dl_vlan(struct flow *, ovs_be16 vid);
void flow_set_vlan_vid(struct flow *, ovs_be16 vid);
void flow_set_vlan_pcp(struct flow *, uint8_t pcp);

int flow_count_mpls_labels(const struct flow *, struct flow_wildcards *);
int flow_count_common_mpls_labels(const struct flow *a, int an,
                                  const struct flow *b, int bn,
                                  struct flow_wildcards *wc);
void flow_push_mpls(struct flow *, int n, ovs_be16 mpls_eth_type,
                    struct flow_wildcards *);
bool flow_pop_mpls(struct flow *, int n, ovs_be16 eth_type,
                   struct flow_wildcards *);
void flow_set_mpls_label(struct flow *, int idx, ovs_be32 label);
void flow_set_mpls_ttl(struct flow *, int idx, uint8_t ttl);
void flow_set_mpls_tc(struct flow *, int idx, uint8_t tc);
void flow_set_mpls_bos(struct flow *, int idx, uint8_t stack);
void flow_set_mpls_lse(struct flow *, int idx, ovs_be32 lse);

void flow_compose(struct ofpbuf *, const struct flow *);

static inline int
flow_compare_3way(const struct flow *a, const struct flow *b)
{
    return memcmp(a, b, sizeof *a);
}

static inline bool
flow_equal(const struct flow *a, const struct flow *b)
{
    return !flow_compare_3way(a, b);
}

static inline size_t
flow_hash(const struct flow *flow, uint32_t basis)
{
    return hash_words((const uint32_t *) flow, sizeof *flow / 4, basis);
}

static inline uint16_t
ofp_to_u16(ofp_port_t ofp_port)
{
    return (OVS_FORCE uint16_t) ofp_port;
}

static inline uint32_t
odp_to_u32(odp_port_t odp_port)
{
    return (OVS_FORCE uint32_t) odp_port;
}

static inline uint32_t
ofp11_to_u32(ofp11_port_t ofp11_port)
{
    return (OVS_FORCE uint32_t) ofp11_port;
}

static inline ofp_port_t
u16_to_ofp(uint16_t port)
{
    return OFP_PORT_C(port);
}

static inline odp_port_t
u32_to_odp(uint32_t port)
{
    return ODP_PORT_C(port);
}

static inline ofp11_port_t
u32_to_ofp11(uint32_t port)
{
    return OFP11_PORT_C(port);
}

static inline uint32_t
hash_ofp_port(ofp_port_t ofp_port)
{
    return hash_int(ofp_to_u16(ofp_port), 0);
}

static inline uint32_t
hash_odp_port(odp_port_t odp_port)
{
    return hash_int(odp_to_u32(odp_port), 0);
}

uint32_t flow_hash_in_minimask(const struct flow *, const struct minimask *,
                               uint32_t basis);
uint32_t flow_hash_in_minimask_range(const struct flow *,
                                     const struct minimask *,
                                     uint8_t start, uint8_t end,
                                     uint32_t *basis);

/* Wildcards for a flow.
 *
 * A 1-bit in each bit in 'masks' indicates that the corresponding bit of
 * the flow is significant (must match).  A 0-bit indicates that the
 * corresponding bit of the flow is wildcarded (need not match). */
struct flow_wildcards {
    struct flow masks;
};

void flow_wildcards_init_catchall(struct flow_wildcards *);

void flow_wildcards_clear_non_packet_fields(struct flow_wildcards *);

bool flow_wildcards_is_catchall(const struct flow_wildcards *);

void flow_wildcards_set_reg_mask(struct flow_wildcards *,
                                 int idx, uint32_t mask);

void flow_wildcards_and(struct flow_wildcards *dst,
                        const struct flow_wildcards *src1,
                        const struct flow_wildcards *src2);
void flow_wildcards_or(struct flow_wildcards *dst,
                       const struct flow_wildcards *src1,
                       const struct flow_wildcards *src2);
bool flow_wildcards_has_extra(const struct flow_wildcards *,
                              const struct flow_wildcards *);

void flow_wildcards_fold_minimask(struct flow_wildcards *,
                                  const struct minimask *);
void flow_wildcards_fold_minimask_range(struct flow_wildcards *,
                                        const struct minimask *,
                                        uint8_t start, uint8_t end);

uint32_t flow_wildcards_hash(const struct flow_wildcards *, uint32_t basis);
bool flow_wildcards_equal(const struct flow_wildcards *,
                          const struct flow_wildcards *);
uint32_t flow_hash_5tuple(const struct flow *flow, uint32_t basis);
uint32_t flow_hash_symmetric_l4(const struct flow *flow, uint32_t basis);

/* Initialize a flow with random fields that matter for nx_hash_fields. */
void flow_random_hash_fields(struct flow *);
void flow_mask_hash_fields(const struct flow *, struct flow_wildcards *,
                           enum nx_hash_fields);
uint32_t flow_hash_fields(const struct flow *, enum nx_hash_fields,
                          uint16_t basis);
const char *flow_hash_fields_to_str(enum nx_hash_fields);
bool flow_hash_fields_valid(enum nx_hash_fields);

uint32_t flow_hash_in_wildcards(const struct flow *,
                                const struct flow_wildcards *,
                                uint32_t basis);

bool flow_equal_except(const struct flow *a, const struct flow *b,
                       const struct flow_wildcards *);

/* Compressed flow. */

#define MINI_N_INLINE (sizeof(void *) == 4 ? 7 : 8)
BUILD_ASSERT_DECL(FLOW_U32S <= 64);

/* A sparse representation of a "struct flow".
 *
 * A "struct flow" is fairly large and tends to be mostly zeros.  Sparse
 * representation has two advantages.  First, it saves memory.  Second, it
 * saves time when the goal is to iterate over only the nonzero parts of the
 * struct.
 *
 * The 'map' member holds one bit for each uint32_t in a "struct flow".  Each
 * 0-bit indicates that the corresponding uint32_t is zero, each 1-bit that it
 * *may* be nonzero.
 *
 * 'values' points to the start of an array that has one element for each 1-bit
 * in 'map'.  The least-numbered 1-bit is in values[0], the next 1-bit is in
 * values[1], and so on.
 *
 * 'values' may point to a few different locations:
 *
 *     - If 'map' has MINI_N_INLINE or fewer 1-bits, it may point to
 *       'inline_values'.  One hopes that this is the common case.
 *
 *     - If 'map' has more than MINI_N_INLINE 1-bits, it may point to memory
 *       allocated with malloc().
 *
 *     - The caller could provide storage on the stack for situations where
 *       that makes sense.  So far that's only proved useful for
 *       minimask_combine(), but the principle works elsewhere.
 *
 * Elements in 'values' are allowed to be zero.  This is useful for "struct
 * minimatch", for which ensuring that the miniflow and minimask members have
 * same 'map' allows optimization.  This allowance applies only to a miniflow
 * that is not a mask.  That is, a minimask may NOT have zero elements in
 * its 'values'.
 */
struct miniflow {
    uint64_t map;
    uint32_t *values;
    uint32_t inline_values[MINI_N_INLINE];
};

/* This is useful for initializing a miniflow for a miniflow_extract() call. */
static inline void miniflow_initialize(struct miniflow *mf,
                                       uint32_t buf[FLOW_U32S])
{
    mf->map = 0;
    mf->values = buf;
}

struct pkt_metadata;

/* The 'dst->values' must be initialized with a buffer with space for
 * FLOW_U32S.  'dst->map' is ignored on input and set on output to
 * indicate which fields were extracted. */
void miniflow_extract(struct ofpbuf *packet, const struct pkt_metadata *,
                      struct miniflow *dst);
void miniflow_init(struct miniflow *, const struct flow *);
void miniflow_init_with_minimask(struct miniflow *, const struct flow *,
                                 const struct minimask *);
void miniflow_clone(struct miniflow *, const struct miniflow *);
void miniflow_move(struct miniflow *dst, struct miniflow *);
void miniflow_destroy(struct miniflow *);

void miniflow_expand(const struct miniflow *, struct flow *);

#define FLOW_U32_SIZE(FIELD)                                            \
    DIV_ROUND_UP(sizeof(((struct flow *)0)->FIELD), sizeof(uint32_t))

#define MINIFLOW_MAP(FIELD)                       \
    (((UINT64_C(1) << FLOW_U32_SIZE(FIELD)) - 1)  \
     << (offsetof(struct flow, FIELD) / 4))

static inline uint32_t
mf_get_next_in_map(uint64_t *fmap, uint64_t rm1bit, const uint32_t **fp,
                   uint32_t *value)
{
    *value = 0;
    if (*fmap & rm1bit) {
        uint64_t trash = *fmap & (rm1bit - 1);

        if (trash) {
            *fmap -= trash;
            *fp += count_1bits(trash);
        }
        *value = **fp;
    }
    return rm1bit != 0;
}

/* Iterate through all miniflow u32 values specified by the 'MAP'.
 * This works as the first statement in a block.*/
#define MINIFLOW_FOR_EACH_IN_MAP(VALUE, FLOW, MAP)                      \
    const uint32_t *fp_ = (FLOW)->values;                               \
    uint64_t rm1bit_, fmap_, map_;                                      \
    for (fmap_ = (FLOW)->map, map_ = (MAP), rm1bit_ = rightmost_1bit(map_); \
         mf_get_next_in_map(&fmap_, rm1bit_, &fp_, &(VALUE));           \
         map_ -= rm1bit_, rm1bit_ = rightmost_1bit(map_))

/* Get the value of 'FIELD' of an up to 4 byte wide integer type 'TYPE' of
 * a miniflow. */
#define MINIFLOW_GET_TYPE(MF, TYPE, OFS)                                \
    (((MF)->map & (UINT64_C(1) << (OFS) / 4))                           \
     ? ((OVS_FORCE const TYPE *)                                        \
        ((MF)->values                                                   \
         + count_1bits((MF)->map & ((UINT64_C(1) << (OFS) / 4) - 1))))  \
       [(OFS) % 4 / sizeof(TYPE)]                                       \
     : 0)                                                               \

#define MINIFLOW_GET_U8(FLOW, FIELD)                                    \
    MINIFLOW_GET_TYPE(FLOW, uint8_t, offsetof(struct flow, FIELD))
#define MINIFLOW_GET_U16(FLOW, FIELD)                                    \
    MINIFLOW_GET_TYPE(FLOW, uint16_t, offsetof(struct flow, FIELD))
#define MINIFLOW_GET_BE16(FLOW, FIELD)                                    \
    MINIFLOW_GET_TYPE(FLOW, ovs_be16, offsetof(struct flow, FIELD))
#define MINIFLOW_GET_U32(FLOW, FIELD)                                    \
    MINIFLOW_GET_TYPE(FLOW, uint32_t, offsetof(struct flow, FIELD))
#define MINIFLOW_GET_BE32(FLOW, FIELD)                                    \
    MINIFLOW_GET_TYPE(FLOW, ovs_be32, offsetof(struct flow, FIELD))

static inline uint16_t miniflow_get_vid(const struct miniflow *);
static inline uint16_t miniflow_get_tcp_flags(const struct miniflow *);
static inline ovs_be64 miniflow_get_metadata(const struct miniflow *);

bool miniflow_equal(const struct miniflow *a, const struct miniflow *b);
bool miniflow_equal_in_minimask(const struct miniflow *a,
                                const struct miniflow *b,
                                const struct minimask *);
bool miniflow_equal_flow_in_minimask(const struct miniflow *a,
                                     const struct flow *b,
                                     const struct minimask *);
uint32_t miniflow_hash(const struct miniflow *, uint32_t basis);
uint32_t miniflow_hash_in_minimask(const struct miniflow *,
                                   const struct minimask *, uint32_t basis);
uint64_t miniflow_get_map_in_range(const struct miniflow *miniflow,
                                   uint8_t start, uint8_t end,
                                   unsigned int *offset);
uint32_t miniflow_hash_5tuple(const struct miniflow *flow, uint32_t basis);


/* Compressed flow wildcards. */

/* A sparse representation of a "struct flow_wildcards".
 *
 * See the large comment on struct miniflow for details.
 *
 * Note: While miniflow can have zero data for a 1-bit in the map,
 * a minimask may not!  We rely on this in the implementation. */
struct minimask {
    struct miniflow masks;
};

void minimask_init(struct minimask *, const struct flow_wildcards *);
void minimask_clone(struct minimask *, const struct minimask *);
void minimask_move(struct minimask *dst, struct minimask *src);
void minimask_combine(struct minimask *dst,
                      const struct minimask *a, const struct minimask *b,
                      uint32_t storage[FLOW_U32S]);
void minimask_destroy(struct minimask *);

void minimask_expand(const struct minimask *, struct flow_wildcards *);

uint32_t minimask_get(const struct minimask *, unsigned int u32_ofs);
static inline uint16_t minimask_get_vid_mask(const struct minimask *);
static inline ovs_be64 minimask_get_metadata_mask(const struct minimask *);

bool minimask_equal(const struct minimask *a, const struct minimask *b);
uint32_t minimask_hash(const struct minimask *, uint32_t basis);

bool minimask_has_extra(const struct minimask *, const struct minimask *);
bool minimask_is_catchall(const struct minimask *);


/* Returns the VID within the vlan_tci member of the "struct flow" represented
 * by 'flow'. */
static inline uint16_t
miniflow_get_vid(const struct miniflow *flow)
{
    ovs_be16 tci = MINIFLOW_GET_BE16(flow, vlan_tci);
    return vlan_tci_to_vid(tci);
}

/* Returns the VID mask within the vlan_tci member of the "struct
 * flow_wildcards" represented by 'mask'. */
static inline uint16_t
minimask_get_vid_mask(const struct minimask *mask)
{
    return miniflow_get_vid(&mask->masks);
}

/* Returns the value of the "tcp_flags" field in 'flow'. */
static inline uint16_t
miniflow_get_tcp_flags(const struct miniflow *flow)
{
    return ntohs(MINIFLOW_GET_BE16(flow, tcp_flags));
}

/* Returns the value of the OpenFlow 1.1+ "metadata" field in 'flow'. */
static inline ovs_be64
miniflow_get_metadata(const struct miniflow *flow)
{
    union {
        ovs_be64 be64;
        struct {
            ovs_be32 hi;
            ovs_be32 lo;
        };
    } value;

    enum { MD_OFS = offsetof(struct flow, metadata) };
    BUILD_ASSERT_DECL(MD_OFS % sizeof(uint32_t) == 0);
    value.hi = MINIFLOW_GET_TYPE(flow, ovs_be32, MD_OFS);
    value.lo = MINIFLOW_GET_TYPE(flow, ovs_be32, MD_OFS + 4);

    return value.be64;
}

/* Returns the mask for the OpenFlow 1.1+ "metadata" field in 'mask'.
 *
 * The return value is all-1-bits if 'mask' matches on the whole value of the
 * metadata field, all-0-bits if 'mask' entirely wildcards the metadata field,
 * or some other value if the metadata field is partially matched, partially
 * wildcarded. */
static inline ovs_be64
minimask_get_metadata_mask(const struct minimask *mask)
{
    return miniflow_get_metadata(&mask->masks);
}

static inline struct pkt_metadata
pkt_metadata_from_flow(const struct flow *flow)
{
    struct pkt_metadata md;

    md.recirc_id = flow->recirc_id;
    md.dp_hash = flow->dp_hash;
    md.tunnel = flow->tunnel;
    md.skb_priority = flow->skb_priority;
    md.pkt_mark = flow->pkt_mark;
    md.in_port = flow->in_port;

    return md;
}

static inline bool is_ip_any(const struct flow *flow)
{
    return dl_type_is_ip_any(flow->dl_type);
}

static inline bool is_icmpv4(const struct flow *flow)
{
    return (flow->dl_type == htons(ETH_TYPE_IP)
            && flow->nw_proto == IPPROTO_ICMP);
}

static inline bool is_icmpv6(const struct flow *flow)
{
    return (flow->dl_type == htons(ETH_TYPE_IPV6)
            && flow->nw_proto == IPPROTO_ICMPV6);
}

static inline bool is_stp(const struct flow *flow)
{
    return (eth_addr_equals(flow->dl_dst, eth_addr_stp)
            && flow->dl_type == htons(FLOW_DL_TYPE_NONE));
}

#endif /* flow.h */