Exemplo n.º 1
0
/* Convert 'str_' (as described in the Flow Syntax section of the ovs-ofctl man
 * page) into 'fm' for sending the specified flow_mod 'command' to a switch.
 * If 'actions' is specified, an action must be in 'string' and may be expanded
 * or reallocated.
 *
 * To parse syntax for an OFPT_FLOW_MOD (or NXT_FLOW_MOD), use an OFPFC_*
 * constant for 'command'.  To parse syntax for an OFPST_FLOW or
 * OFPST_AGGREGATE (or NXST_FLOW or NXST_AGGREGATE), use -1 for 'command'. */
void
parse_ofp_str(struct ofputil_flow_mod *fm, int command, const char *str_,
              bool verbose)
{
    enum {
        F_OUT_PORT = 1 << 0,
        F_ACTIONS = 1 << 1,
        F_TIMEOUT = 1 << 3,
        F_PRIORITY = 1 << 4,
        F_FLAGS = 1 << 5,
    } fields;
    char *string = xstrdup(str_);
    char *save_ptr = NULL;
    char *act_str = NULL;
    char *name;

    switch (command) {
    case -1:
        fields = F_OUT_PORT;
        break;

    case OFPFC_ADD:
        fields = F_ACTIONS | F_TIMEOUT | F_PRIORITY | F_FLAGS;
        break;

    case OFPFC_DELETE:
        fields = F_OUT_PORT;
        break;

    case OFPFC_DELETE_STRICT:
        fields = F_OUT_PORT | F_PRIORITY;
        break;

    case OFPFC_MODIFY:
        fields = F_ACTIONS | F_TIMEOUT | F_PRIORITY | F_FLAGS;
        break;

    case OFPFC_MODIFY_STRICT:
        fields = F_ACTIONS | F_TIMEOUT | F_PRIORITY | F_FLAGS;
        break;

    default:
        NOT_REACHED();
    }

    match_init_catchall(&fm->match);
    fm->priority = OFP_DEFAULT_PRIORITY;
    fm->cookie = htonll(0);
    fm->cookie_mask = htonll(0);
    if (command == OFPFC_MODIFY || command == OFPFC_MODIFY_STRICT) {
        /* For modify, by default, don't update the cookie. */
        fm->new_cookie = htonll(UINT64_MAX);
    } else{
        fm->new_cookie = htonll(0);
    }
    fm->table_id = 0xff;
    fm->command = command;
    fm->idle_timeout = OFP_FLOW_PERMANENT;
    fm->hard_timeout = OFP_FLOW_PERMANENT;
    fm->buffer_id = UINT32_MAX;
    fm->out_port = OFPP_ANY;
    fm->flags = 0;
    if (fields & F_ACTIONS) {
        act_str = strstr(string, "action");
        if (!act_str) {
            ofp_fatal(str_, verbose, "must specify an action");
        }
        *act_str = '\0';

        act_str = strchr(act_str + 1, '=');
        if (!act_str) {
            ofp_fatal(str_, verbose, "must specify an action");
        }

        act_str++;
    }
    for (name = strtok_r(string, "=, \t\r\n", &save_ptr); name;
         name = strtok_r(NULL, "=, \t\r\n", &save_ptr)) {
        const struct protocol *p;

        if (parse_protocol(name, &p)) {
            match_set_dl_type(&fm->match, htons(p->dl_type));
            if (p->nw_proto) {
                match_set_nw_proto(&fm->match, p->nw_proto);
            }
        } else if (fields & F_FLAGS && !strcmp(name, "send_flow_rem")) {
            fm->flags |= OFPFF_SEND_FLOW_REM;
        } else if (fields & F_FLAGS && !strcmp(name, "check_overlap")) {
            fm->flags |= OFPFF_CHECK_OVERLAP;
        } else if (fields & F_FLAGS && !strcmp(name, "reset_counts")) {
            fm->flags |= OFPFF12_RESET_COUNTS;
        } else if (fields & F_FLAGS && !strcmp(name, "no_packet_counts")) {
            fm->flags |= OFPFF13_NO_PKT_COUNTS;
        } else if (fields & F_FLAGS && !strcmp(name, "no_byte_counts")) {
            fm->flags |= OFPFF13_NO_BYT_COUNTS;
        } else {
            char *value;

            value = strtok_r(NULL, ", \t\r\n", &save_ptr);
            if (!value) {
                ofp_fatal(str_, verbose, "field %s missing value", name);
            }

            if (!strcmp(name, "table")) {
                fm->table_id = str_to_u8(value, name);
            } else if (!strcmp(name, "out_port")) {
                if (!ofputil_port_from_string(value, &fm->out_port)) {
                    ofp_fatal(str_, verbose, "%s is not a valid OpenFlow port",
                              name);
                }
            } else if (fields & F_PRIORITY && !strcmp(name, "priority")) {
                fm->priority = str_to_u16(value, name);
            } else if (fields & F_TIMEOUT && !strcmp(name, "idle_timeout")) {
                fm->idle_timeout = str_to_u16(value, name);
            } else if (fields & F_TIMEOUT && !strcmp(name, "hard_timeout")) {
                fm->hard_timeout = str_to_u16(value, name);
            } else if (!strcmp(name, "cookie")) {
                char *mask = strchr(value, '/');

                if (mask) {
                    /* A mask means we're searching for a cookie. */
                    if (command == OFPFC_ADD) {
                        ofp_fatal(str_, verbose, "flow additions cannot use "
                                  "a cookie mask");
                    }
                    *mask = '\0';
                    fm->cookie = htonll(str_to_u64(value));
                    fm->cookie_mask = htonll(str_to_u64(mask+1));
                } else {
                    /* No mask means that the cookie is being set. */
                    if (command != OFPFC_ADD && command != OFPFC_MODIFY
                            && command != OFPFC_MODIFY_STRICT) {
                        ofp_fatal(str_, verbose, "cannot set cookie");
                    }
                    fm->new_cookie = htonll(str_to_u64(value));
                }
            } else if (mf_from_name(name)) {
                parse_field(mf_from_name(name), value, &fm->match);
            } else if (!strcmp(name, "duration")
                       || !strcmp(name, "n_packets")
                       || !strcmp(name, "n_bytes")
                       || !strcmp(name, "idle_age")
                       || !strcmp(name, "hard_age")) {
                /* Ignore these, so that users can feed the output of
                 * "ovs-ofctl dump-flows" back into commands that parse
                 * flows. */
            } else {
                ofp_fatal(str_, verbose, "unknown keyword %s", name);
            }
        }
    }
    if (!fm->cookie_mask && fm->new_cookie == htonll(UINT64_MAX)
            && (command == OFPFC_MODIFY || command == OFPFC_MODIFY_STRICT)) {
        /* On modifies without a mask, we are supposed to add a flow if
         * one does not exist.  If a cookie wasn't been specified, use a
         * default of zero. */
        fm->new_cookie = htonll(0);
    }
    if (fields & F_ACTIONS) {
        struct ofpbuf ofpacts;
        enum ofperr err;

        ofpbuf_init(&ofpacts, 32);
        str_to_inst_ofpacts(act_str, &ofpacts);
        fm->ofpacts_len = ofpacts.size;
        fm->ofpacts = ofpbuf_steal_data(&ofpacts);

        err = ofpacts_check(fm->ofpacts, fm->ofpacts_len, &fm->match.flow,
                            OFPP_MAX, 0);
        if (err) {
            exit(EXIT_FAILURE);
        }

    } else {
        fm->ofpacts_len = 0;
        fm->ofpacts = NULL;
    }

    free(string);
}
Exemplo n.º 2
0
/* Convert 'str_' (as described in the Flow Syntax section of the ovs-ofctl man
 * page) into 'mm' for sending the specified meter_mod 'command' to a switch.
 */
void
parse_ofp_meter_mod_str(struct ofputil_meter_mod *mm, const char *str_,
                        int command, bool verbose)
{
    enum {
        F_METER = 1 << 0,
        F_FLAGS = 1 << 1,
        F_BANDS = 1 << 2,
    } fields;
    char *string = xstrdup(str_);
    char *save_ptr = NULL;
    char *band_str = NULL;
    char *name;

    switch (command) {
    case -1:
        fields = F_METER;
        break;

    case OFPMC13_ADD:
        fields = F_METER | F_FLAGS | F_BANDS;
        break;

    case OFPMC13_DELETE:
        fields = F_METER;
        break;

    case OFPMC13_MODIFY:
        fields = F_METER | F_FLAGS | F_BANDS;
        break;

    default:
        NOT_REACHED();
    }

    mm->command = command;
    mm->meter.meter_id = 0;
    mm->meter.flags = 0;
    if (fields & F_BANDS) {
        band_str = strstr(string, "band");
        if (!band_str) {
            ofp_fatal(str_, verbose, "must specify bands");
        }
        *band_str = '\0';

        band_str = strchr(band_str + 1, '=');
        if (!band_str) {
            ofp_fatal(str_, verbose, "must specify bands");
        }

        band_str++;
    }
    for (name = strtok_r(string, "=, \t\r\n", &save_ptr); name;
         name = strtok_r(NULL, "=, \t\r\n", &save_ptr)) {

        if (fields & F_FLAGS && !strcmp(name, "kbps")) {
            mm->meter.flags |= OFPMF13_KBPS;
        } else if (fields & F_FLAGS && !strcmp(name, "pktps")) {
            mm->meter.flags |= OFPMF13_PKTPS;
        } else if (fields & F_FLAGS && !strcmp(name, "burst")) {
            mm->meter.flags |= OFPMF13_BURST;
        } else if (fields & F_FLAGS && !strcmp(name, "stats")) {
            mm->meter.flags |= OFPMF13_STATS;
        } else {
            char *value;

            value = strtok_r(NULL, ", \t\r\n", &save_ptr);
            if (!value) {
                ofp_fatal(str_, verbose, "field %s missing value", name);
            }

            if (!strcmp(name, "meter")) {
                if (!strcmp(value, "all")) {
                    mm->meter.meter_id = OFPM13_ALL;
                } else if (!strcmp(value, "controller")) {
                    mm->meter.meter_id = OFPM13_CONTROLLER;
                } else if (!strcmp(value, "slowpath")) {
                    mm->meter.meter_id = OFPM13_SLOWPATH;
                } else {
                    mm->meter.meter_id = str_to_u32(value);
                    if (mm->meter.meter_id > OFPM13_MAX) {
                        ofp_fatal(str_, verbose, "invalid value for %s", name);
                    }
                }
            } else {
                ofp_fatal(str_, verbose, "unknown keyword %s", name);
            }
        }
    }
    if (fields & F_METER && !mm->meter.meter_id) {
        ofp_fatal(str_, verbose, "must specify 'meter'");
    }
    if (fields & F_FLAGS && !mm->meter.flags) {
        ofp_fatal(str_, verbose,
                  "meter must specify either 'kbps' or 'pktps'");
    }

    if (fields & F_BANDS) {
        struct ofpbuf bands;
        uint16_t n_bands = 0;
        struct ofputil_meter_band *band = NULL;
        int i;

        ofpbuf_init(&bands, 64);

        for (name = strtok_r(band_str, "=, \t\r\n", &save_ptr); name;
             name = strtok_r(NULL, "=, \t\r\n", &save_ptr)) {

            char *value;

            value = strtok_r(NULL, ", \t\r\n", &save_ptr);
            if (!value) {
                ofp_fatal(str_, verbose, "field %s missing value", name);
            }

            if (!strcmp(name, "type")) {
                /* Start a new band */
                band = ofpbuf_put_zeros(&bands, sizeof *band);
                n_bands++;

                if (!strcmp(value, "drop")) {
                    band->type = OFPMBT13_DROP;
                } else if (!strcmp(value, "dscp_remark")) {
                    band->type = OFPMBT13_DSCP_REMARK;
                } else {
                    ofp_fatal(str_, verbose, "field %s unknown value %s", name,
                              value);
                }
            } else if (!band || !band->type) {
                ofp_fatal(str_, verbose,
                          "band must start with the 'type' keyword");
            } else if (!strcmp(name, "rate")) {
                band->rate = str_to_u32(value);
            } else if (!strcmp(name, "burst_size")) {
                band->burst_size = str_to_u32(value);
            } else if (!strcmp(name, "prec_level")) {
                band->prec_level = str_to_u8(value, name);
            } else {
                ofp_fatal(str_, verbose, "unknown keyword %s", name);
            }
        }
        /* validate bands */
        if (!n_bands) {
            ofp_fatal(str_, verbose, "meter must have bands");
        }

        mm->meter.n_bands = n_bands;
        mm->meter.bands = ofpbuf_steal_data(&bands);

        for (i = 0; i < n_bands; ++i) {
            band = &mm->meter.bands[i];

            if (!band->type) {
                ofp_fatal(str_, verbose, "band must have 'type'");
            }
            if (band->type == OFPMBT13_DSCP_REMARK) {
                if (!band->prec_level) {
                    ofp_fatal(str_, verbose, "'dscp_remark' band must have"
                              " 'prec_level'");
                }
            } else {
                if (band->prec_level) {
                    ofp_fatal(str_, verbose, "Only 'dscp_remark' band may have"
                              " 'prec_level'");
                }
            }
            if (!band->rate) {
                ofp_fatal(str_, verbose, "band must have 'rate'");
            }
            if (mm->meter.flags & OFPMF13_BURST) {
                if (!band->burst_size) {
                    ofp_fatal(str_, verbose, "band must have 'burst_size' "
                              "when 'burst' flag is set");
                }
            } else {
                if (band->burst_size) {
                    ofp_fatal(str_, verbose, "band may have 'burst_size' only "
                              "when 'burst' flag is set");
                }
            }
        }
    } else {
        mm->meter.n_bands = 0;
        mm->meter.bands = NULL;
    }

    free(string);
}
Exemplo n.º 3
0
/* Convert 'str_' (as described in the Flow Syntax section of the ovs-ofctl man
 * page) into 'fm' for sending the specified flow_mod 'command' to a switch.
 * If 'actions' is specified, an action must be in 'string' and may be expanded
 * or reallocated.
 *
 * To parse syntax for an OFPT_FLOW_MOD (or NXT_FLOW_MOD), use an OFPFC_*
 * constant for 'command'.  To parse syntax for an OFPST_FLOW or
 * OFPST_AGGREGATE (or NXST_FLOW or NXST_AGGREGATE), use -1 for 'command'. */
void
parse_ofp_str(struct ofputil_flow_mod *fm, int command, const char *str_,
              bool verbose)
{
    enum {
        F_OUT_PORT = 1 << 0,
        F_ACTIONS = 1 << 1,
        F_TIMEOUT = 1 << 3,
        F_PRIORITY = 1 << 4
    } fields;
    char *string = xstrdup(str_);
    char *save_ptr = NULL;
    char *act_str = NULL;
    char *name;

    switch (command) {
    case -1:
        fields = F_OUT_PORT;
        break;

    case OFPFC_ADD:
        fields = F_ACTIONS | F_TIMEOUT | F_PRIORITY;
        break;

    case OFPFC_DELETE:
        fields = F_OUT_PORT;
        break;

    case OFPFC_DELETE_STRICT:
        fields = F_OUT_PORT | F_PRIORITY;
        break;

    case OFPFC_MODIFY:
        fields = F_ACTIONS;
        break;

    case OFPFC_MODIFY_STRICT:
        fields = F_ACTIONS | F_PRIORITY;
        break;

    default:
        NOT_REACHED();
    }

    cls_rule_init_catchall(&fm->cr, OFP_DEFAULT_PRIORITY);
    fm->cookie = htonll(0);
    fm->cookie_mask = htonll(0);
    if (command == OFPFC_MODIFY || command == OFPFC_MODIFY_STRICT) {
        /* For modify, by default, don't update the cookie. */
        fm->new_cookie = htonll(UINT64_MAX);
    } else{
        fm->new_cookie = htonll(0);
    }
    fm->table_id = 0xff;
    fm->command = command;
    fm->idle_timeout = OFP_FLOW_PERMANENT;
    fm->hard_timeout = OFP_FLOW_PERMANENT;
    fm->buffer_id = UINT32_MAX;
    fm->out_port = OFPP_NONE;
    fm->flags = 0;
    if (fields & F_ACTIONS) {
        act_str = strstr(string, "action");
        if (!act_str) {
            ofp_fatal(str_, verbose, "must specify an action");
        }
        *act_str = '\0';

        act_str = strchr(act_str + 1, '=');
        if (!act_str) {
            ofp_fatal(str_, verbose, "must specify an action");
        }

        act_str++;
    }
    for (name = strtok_r(string, "=, \t\r\n", &save_ptr); name;
         name = strtok_r(NULL, "=, \t\r\n", &save_ptr)) {
        const struct protocol *p;

        if (parse_protocol(name, &p)) {
            cls_rule_set_dl_type(&fm->cr, htons(p->dl_type));
            if (p->nw_proto) {
                cls_rule_set_nw_proto(&fm->cr, p->nw_proto);
            }
        } else {
            char *value;

            value = strtok_r(NULL, ", \t\r\n", &save_ptr);
            if (!value) {
                ofp_fatal(str_, verbose, "field %s missing value", name);
            }

            if (!strcmp(name, "table")) {
                fm->table_id = str_to_table_id(value);
            } else if (!strcmp(name, "out_port")) {
                fm->out_port = atoi(value);
            } else if (fields & F_PRIORITY && !strcmp(name, "priority")) {
                fm->cr.priority = str_to_u16(value, name);
            } else if (fields & F_TIMEOUT && !strcmp(name, "idle_timeout")) {
                fm->idle_timeout = str_to_u16(value, name);
            } else if (fields & F_TIMEOUT && !strcmp(name, "hard_timeout")) {
                fm->hard_timeout = str_to_u16(value, name);
            } else if (!strcmp(name, "cookie")) {
                char *mask = strchr(value, '/');

                if (mask) {
                    /* A mask means we're searching for a cookie. */
                    if (command == OFPFC_ADD) {
                        ofp_fatal(str_, verbose, "flow additions cannot use "
                                  "a cookie mask");
                    }
                    *mask = '\0';
                    fm->cookie = htonll(str_to_u64(value));
                    fm->cookie_mask = htonll(str_to_u64(mask+1));
                } else {
                    /* No mask means that the cookie is being set. */
                    if (command != OFPFC_ADD && command != OFPFC_MODIFY
                            && command != OFPFC_MODIFY_STRICT) {
                        ofp_fatal(str_, verbose, "cannot set cookie");
                    }
                    fm->new_cookie = htonll(str_to_u64(value));
                }
            } else if (mf_from_name(name)) {
                parse_field(mf_from_name(name), value, &fm->cr);
            } else if (!strcmp(name, "duration")
                       || !strcmp(name, "n_packets")
                       || !strcmp(name, "n_bytes")) {
                /* Ignore these, so that users can feed the output of
                 * "ovs-ofctl dump-flows" back into commands that parse
                 * flows. */
            } else {
                ofp_fatal(str_, verbose, "unknown keyword %s", name);
            }
        }
    }
    if (!fm->cookie_mask && fm->new_cookie == htonll(UINT64_MAX)
            && (command == OFPFC_MODIFY || command == OFPFC_MODIFY_STRICT)) {
        /* On modifies without a mask, we are supposed to add a flow if
         * one does not exist.  If a cookie wasn't been specified, use a
         * default of zero. */
        fm->new_cookie = htonll(0);
    }
    if (fields & F_ACTIONS) {
        struct ofpbuf actions;

        ofpbuf_init(&actions, sizeof(union ofp_action));
        str_to_action(&fm->cr.flow, act_str, &actions);
        fm->actions = ofpbuf_steal_data(&actions);
        fm->n_actions = actions.size / sizeof(union ofp_action);
    } else {
        fm->actions = NULL;
        fm->n_actions = 0;
    }

    free(string);
}
Exemplo n.º 4
0
void
learn_execute(const struct nx_action_learn *learn, const struct flow *flow,
              struct ofputil_flow_mod *fm)
{
    const void *p, *end;
    struct ofpbuf actions;

    cls_rule_init_catchall(&fm->cr, ntohs(learn->priority));
    fm->cookie = htonll(0);
    fm->cookie_mask = htonll(0);
    fm->new_cookie = learn->cookie;
    fm->table_id = learn->table_id;
    fm->command = OFPFC_MODIFY_STRICT;
    fm->idle_timeout = ntohs(learn->idle_timeout);
    fm->hard_timeout = ntohs(learn->hard_timeout);
    fm->buffer_id = UINT32_MAX;
    fm->out_port = OFPP_NONE;
    fm->flags = ntohs(learn->flags) & OFPFF_SEND_FLOW_REM;
    fm->actions = NULL;
    fm->n_actions = 0;

    ofpbuf_init(&actions, 64);

    if (learn->fin_idle_timeout || learn->fin_hard_timeout) {
        struct nx_action_fin_timeout *naft;

        naft = ofputil_put_NXAST_FIN_TIMEOUT(&actions);
        naft->fin_idle_timeout = learn->fin_idle_timeout;
        naft->fin_hard_timeout = learn->fin_hard_timeout;
    }

    for (p = learn + 1, end = (char *) learn + ntohs(learn->len); p != end; ) {
        uint16_t header = ntohs(get_be16(&p));
        int n_bits = header & NX_LEARN_N_BITS_MASK;
        int src_type = header & NX_LEARN_SRC_MASK;
        int dst_type = header & NX_LEARN_DST_MASK;
        union mf_subvalue value;

        struct mf_subfield dst;
        int chunk, ofs;

        if (!header) {
            break;
        }

        if (src_type == NX_LEARN_SRC_FIELD) {
            struct mf_subfield src;

            get_subfield(n_bits, &p, &src);
            mf_read_subfield(&src, flow, &value);
        } else {
            int p_bytes = 2 * DIV_ROUND_UP(n_bits, 16);

            memset(&value, 0, sizeof value);
            bitwise_copy(p, p_bytes, 0,
                         &value, sizeof value, 0,
                         n_bits);
            p = (const uint8_t *) p + p_bytes;
        }

        switch (dst_type) {
        case NX_LEARN_DST_MATCH:
            get_subfield(n_bits, &p, &dst);
            mf_write_subfield(&dst, &value, &fm->cr);
            break;

        case NX_LEARN_DST_LOAD:
            get_subfield(n_bits, &p, &dst);
            for (ofs = 0; ofs < n_bits; ofs += chunk) {
                struct nx_action_reg_load *load;

                chunk = MIN(n_bits - ofs, 64);

                load = ofputil_put_NXAST_REG_LOAD(&actions);
                load->ofs_nbits = nxm_encode_ofs_nbits(dst.ofs + ofs, chunk);
                load->dst = htonl(dst.field->nxm_header);
                bitwise_copy(&value, sizeof value, ofs,
                             &load->value, sizeof load->value, 0,
                             chunk);
            }
            break;

        case NX_LEARN_DST_OUTPUT:
            if (n_bits <= 16 || is_all_zeros(value.u8, sizeof value - 2)) {
                ofputil_put_OFPAT10_OUTPUT(&actions)->port = value.be16[7];
            }
            break;
        }
    }

    fm->actions = ofpbuf_steal_data(&actions);
    fm->n_actions = actions.size / sizeof(struct ofp_action_header);
}
void
learn_execute(const struct nx_action_learn *learn, const struct flow *flow,
              struct ofputil_flow_mod *fm)
{
    const void *p, *end;
    struct ofpbuf actions;

    cls_rule_init_catchall(&fm->cr, ntohs(learn->priority));
    fm->cookie = learn->cookie;
    fm->table_id = learn->table_id;
    fm->command = OFPFC_MODIFY_STRICT;
    fm->idle_timeout = ntohs(learn->idle_timeout);
    fm->hard_timeout = ntohs(learn->hard_timeout);
    fm->buffer_id = UINT32_MAX;
    fm->out_port = OFPP_NONE;
    fm->flags = ntohs(learn->flags) & OFPFF_SEND_FLOW_REM;
    fm->actions = NULL;
    fm->n_actions = 0;

    ofpbuf_init(&actions, 64);

    for (p = learn + 1, end = (char *) learn + ntohs(learn->len); p != end; ) {
        uint16_t header = ntohs(get_be16(&p));
        int n_bits = header & NX_LEARN_N_BITS_MASK;
        int src_type = header & NX_LEARN_SRC_MASK;
        int dst_type = header & NX_LEARN_DST_MASK;
        uint64_t value;

        struct nx_action_reg_load *load;
        ovs_be32 dst_field;
        int dst_ofs;

        if (!header) {
            break;
        }

        if (src_type == NX_LEARN_SRC_FIELD) {
            ovs_be32 src_field = get_be32(&p);
            int src_ofs = ntohs(get_be16(&p));

            value = nxm_read_field_bits(src_field,
                                        nxm_encode_ofs_nbits(src_ofs, n_bits),
                                        flow);
        } else {
            value = get_bits(n_bits, &p);
        }

        switch (dst_type) {
        case NX_LEARN_DST_MATCH:
            dst_field = get_be32(&p);
            dst_ofs = ntohs(get_be16(&p));
            mf_set_subfield(mf_from_nxm_header(ntohl(dst_field)), value,
                            dst_ofs, n_bits, &fm->cr);
            break;

        case NX_LEARN_DST_LOAD:
            dst_field = get_be32(&p);
            dst_ofs = ntohs(get_be16(&p));
            load = ofputil_put_NXAST_REG_LOAD(&actions);
            load->ofs_nbits = nxm_encode_ofs_nbits(dst_ofs, n_bits);
            load->dst = dst_field;
            load->value = htonll(value);
            break;

        case NX_LEARN_DST_OUTPUT:
            ofputil_put_OFPAT_OUTPUT(&actions)->port = htons(value);
            break;
        }
    }

    fm->actions = ofpbuf_steal_data(&actions);
    fm->n_actions = actions.size / sizeof(struct ofp_action_header);
}