/*

 * Copyright (c) 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.

 */

#include <config.h>

#include "learn.h"

#include "byte-order.h"

#include "colors.h"

#include "nx-match.h"

#include "openflow/openflow.h"

#include "openvswitch/dynamic-string.h"

#include "openvswitch/match.h"

#include "openvswitch/meta-flow.h"

#include "openvswitch/ofp-actions.h"

#include "openvswitch/ofp-errors.h"

#include "openvswitch/ofp-flow.h"

#include "openvswitch/ofp-parse.h"

#include "openvswitch/ofp-table.h"

#include "openvswitch/ofpbuf.h"

#include "vl-mff-map.h"

#include "unaligned.h"

/* Checks that 'learn' is a valid action on 'flow'.  Returns 0 if it is valid,

 * otherwise an OFPERR_*. */

enum ofperr

learn_check(const struct ofpact_learn *learn, const struct match *src_match)

{

    const struct ofpact_learn_spec *spec;

    struct match dst_match;

    match_init_catchall(&dst_match);

    OFPACT_LEARN_SPEC_FOR_EACH (spec, learn) {

        enum ofperr error;

        /* Check the source. */

        if (spec->src_type == NX_LEARN_SRC_FIELD) {

            error = mf_check_src(&spec->src, src_match);

            if (error) {

                return error;

            }

        }

        /* Check the destination. */

        switch (spec->dst_type) {

        case NX_LEARN_DST_MATCH:

            error = mf_check_src(&spec->dst, &dst_match);

            if (error) {

                return error;

            }

            if (spec->src_type & NX_LEARN_SRC_IMMEDIATE) {

                mf_write_subfield_value(&spec->dst,

                                        ofpact_learn_spec_imm(spec),

                                        &dst_match);

            }

            break;

        case NX_LEARN_DST_LOAD:

            error = mf_check_dst(&spec->dst, &dst_match);

            if (error) {

                return error;

            }

            break;

        case NX_LEARN_DST_OUTPUT:

            /* Nothing to do. */

            break;

        }

    }

    return 0;

}

/* Composes 'fm' so that executing it will implement 'learn' given that the

 * packet being processed has 'flow' as its flow.

 *

 * Uses 'ofpacts' to store the flow mod's actions.  The caller must initialize

 * 'ofpacts' and retains ownership of it.  'fm->ofpacts' will point into the

 * 'ofpacts' buffer.

 *

 * The caller must eventually destroy fm->match.

 *

 * The caller has to actually execute 'fm'. */

void

learn_execute(const struct ofpact_learn *learn, const struct flow *flow,

              struct ofputil_flow_mod *fm, struct ofpbuf *ofpacts)

{

    const struct ofpact_learn_spec *spec;

    struct match match;

    match_init_catchall(&match);

    fm->priority = learn->priority;

    fm->cookie = htonll(0);

    fm->cookie_mask = htonll(0);

    fm->new_cookie = learn->cookie;

    fm->modify_cookie = fm->new_cookie != OVS_BE64_MAX;

    fm->table_id = learn->table_id;

    fm->command = OFPFC_MODIFY_STRICT;

    fm->idle_timeout = learn->idle_timeout;

    fm->hard_timeout = learn->hard_timeout;

    fm->importance = 0;

    fm->buffer_id = UINT32_MAX;

    fm->out_port = OFPP_NONE;

    fm->ofpacts_tlv_bitmap = 0;

    fm->flags = 0;

    if (learn->flags & NX_LEARN_F_SEND_FLOW_REM) {

        fm->flags |= OFPUTIL_FF_SEND_FLOW_REM;

    }

    fm->ofpacts = NULL;

    fm->ofpacts_len = 0;

    if (learn->fin_idle_timeout || learn->fin_hard_timeout) {

        struct ofpact_fin_timeout *oft;

        oft = ofpact_put_FIN_TIMEOUT(ofpacts);

        oft->fin_idle_timeout = learn->fin_idle_timeout;

        oft->fin_hard_timeout = learn->fin_hard_timeout;

    }

    OFPACT_LEARN_SPEC_FOR_EACH (spec, learn) {

        struct ofpact_set_field *sf;

        union mf_subvalue value;

        if (spec->src_type == NX_LEARN_SRC_FIELD) {

            mf_read_subfield(&spec->src, flow, &value);

        } else {

            mf_subvalue_from_value(&spec->dst, &value,

                                   ofpact_learn_spec_imm(spec));

        }

        switch (spec->dst_type) {

        case NX_LEARN_DST_MATCH:

            mf_write_subfield(&spec->dst, &value, &match);

            match_add_ethernet_prereq(&match, spec->dst.field);

            mf_vl_mff_set_tlv_bitmap(

                spec->dst.field, &match.flow.tunnel.metadata.present.map);

            break;

        case NX_LEARN_DST_LOAD:

            sf = ofpact_put_reg_load(ofpacts, spec->dst.field, NULL, NULL);

            bitwise_copy(&value, sizeof value, 0,

                         sf->value, spec->dst.field->n_bytes, spec->dst.ofs,

                         spec->n_bits);

            bitwise_one(ofpact_set_field_mask(sf), spec->dst.field->n_bytes,

                        spec->dst.ofs, spec->n_bits);

            mf_vl_mff_set_tlv_bitmap(spec->dst.field, &fm->ofpacts_tlv_bitmap);

            break;

        case NX_LEARN_DST_OUTPUT:

            if (spec->n_bits <= 16

                || is_all_zeros(value.u8, sizeof value - 2)) {

                ofp_port_t port = u16_to_ofp(ntohll(value.integer));

                if (ofp_to_u16(port) < ofp_to_u16(OFPP_MAX)

                    || port == OFPP_IN_PORT

                    || port == OFPP_FLOOD

                    || port == OFPP_LOCAL

                    || port == OFPP_ALL) {

                    ofpact_put_OUTPUT(ofpacts)->port = port;

                }

            }

            break;

        }

    }

    minimatch_init(&fm->match, &match);

    fm->ofpacts = ofpacts->data;

    fm->ofpacts_len = ofpacts->size;

}

/* Perform a bitwise-OR on 'wc''s fields that are relevant as sources in

 * the learn action 'learn'. */

void

learn_mask(const struct ofpact_learn *learn, struct flow_wildcards *wc)

{

    const struct ofpact_learn_spec *spec;

    union mf_subvalue value;

    memset(&value, 0xff, sizeof value);

    OFPACT_LEARN_SPEC_FOR_EACH (spec, learn) {

        if (spec->src_type == NX_LEARN_SRC_FIELD) {

            mf_write_subfield_flow(&spec->src, &value, &wc->masks);

        }

    }

}

/* Returns NULL if successful, otherwise a malloc()'d string describing the

 * error.  The caller is responsible for freeing the returned string. */

static char * OVS_WARN_UNUSED_RESULT

learn_parse_load_immediate(union mf_subvalue *imm, const char *s,

                           const char *full_s, struct ofpact_learn_spec *spec,

                           struct ofpbuf *ofpacts)

{

    struct mf_subfield dst;

    char *error;

    error = mf_parse_subfield(&dst, s);

    if (error) {

        return error;

    }

    if (!mf_nxm_header(dst.field->id)) {

        return xasprintf("%s: experimenter OXM field '%s' not supported",

                         full_s, s);

    }

    if (!bitwise_is_all_zeros(imm, sizeof *imm, dst.n_bits,

                              (8 * sizeof *imm) - dst.n_bits)) {

        return xasprintf("%s: value does not fit into %u bits",

                         full_s, dst.n_bits);

    }

    spec->n_bits = dst.n_bits;

    spec->src_type = NX_LEARN_SRC_IMMEDIATE;

    spec->dst_type = NX_LEARN_DST_LOAD;

    spec->dst = dst;

    /* Push value last, as this may reallocate 'spec'! */

    unsigned int n_bytes = DIV_ROUND_UP(dst.n_bits, 8);

    uint8_t *src_imm = ofpbuf_put_zeros(ofpacts, OFPACT_ALIGN(n_bytes));

    memcpy(src_imm, &imm->u8[sizeof imm->u8 - n_bytes], n_bytes);

    return NULL;

}

/* Returns NULL if successful, otherwise a malloc()'d string describing the

 * error.  The caller is responsible for freeing the returned string. */

static char * OVS_WARN_UNUSED_RESULT

learn_parse_spec(const char *orig, char *name, char *value,

                 const struct ofputil_port_map *port_map,

                 struct ofpact_learn_spec *spec,

                 struct ofpbuf *ofpacts)

{

    /* Parse destination and check prerequisites. */

    struct mf_subfield dst;

    char *error = mf_parse_subfield(&dst, name);

    bool parse_error = error != NULL;

    free(error);

    if (!parse_error) {

        if (!mf_nxm_header(dst.field->id)) {

            return xasprintf("%s: experimenter OXM field '%s' not supported",

                             orig, name);

        }

        spec->dst = dst;

        spec->n_bits = dst.n_bits;

        spec->dst_type = NX_LEARN_DST_MATCH;

        /* Parse source and check prerequisites. */

        if (value[0] != '\0') {

            struct mf_subfield src;

            error = mf_parse_subfield(&src, value);

            if (error) {

                union mf_value imm;

                char *imm_error = NULL;

                /* Try an immediate value. */

                if (dst.ofs == 0 && dst.n_bits == dst.field->n_bits) {

                    /* Full field value. */

                    imm_error = mf_parse_value(dst.field, value, port_map,

                                               &imm);

                } else {

                    char *tail;

                    /* Partial field value. */

                    if (parse_int_string(value, imm.b,

                                          dst.field->n_bytes, &tail)

                        || *tail != 0) {

                        imm_error = xasprintf("%s: cannot parse integer value", orig);

                    }

                    if (!imm_error &&

                        !bitwise_is_all_zeros(imm.b, dst.field->n_bytes,

                                              dst.n_bits,

                                              dst.field->n_bytes * 8 - dst.n_bits)) {

                        struct ds ds;

                        ds_init(&ds);

                        mf_format(dst.field, &imm, NULL, NULL, &ds);

                        imm_error = xasprintf("%s: value %s does not fit into %d bits",

                                              orig, ds_cstr(&ds), dst.n_bits);

                        ds_destroy(&ds);

                    }

                }

                if (imm_error) {

                    char *err = xasprintf("%s: %s value %s cannot be parsed as a subfield (%s) or an immediate value (%s)",

                                          orig, name, value, error, imm_error);

                    free(error);

                    free(imm_error);

                    return err;

                }

                spec->src_type = NX_LEARN_SRC_IMMEDIATE;

                /* Push value last, as this may reallocate 'spec'! */

                unsigned int imm_bytes = DIV_ROUND_UP(dst.n_bits, 8);

                uint8_t *src_imm = ofpbuf_put_zeros(ofpacts,

                                                    OFPACT_ALIGN(imm_bytes));

                memcpy(src_imm, &imm.b[dst.field->n_bytes - imm_bytes],

                       imm_bytes);

                free(error);

                return NULL;

            }

            spec->src = src;

            if (spec->src.n_bits != spec->dst.n_bits) {

                return xasprintf("%s: bit widths of %s (%u) and %s (%u) "

                                 "differ", orig, name, spec->src.n_bits, value,

                                 spec->dst.n_bits);

            }

        } else {

            spec->src = spec->dst;

        }

        spec->src_type = NX_LEARN_SRC_FIELD;

    } else if (!strcmp(name, "load")) {

        union mf_subvalue imm;

        char *tail;

        char *dst_value = strstr(value, "->");

        if (dst_value == value) {

            return xasprintf("%s: missing source before `->' in `%s'", name,

                             value);

        }

        if (!dst_value) {

            return xasprintf("%s: missing `->' in `%s'", name, value);

        }

        if (!parse_int_string(value, imm.u8, sizeof imm.u8, (char **) &tail)

            && tail != value) {

            if (tail != dst_value) {

                return xasprintf("%s: garbage before `->' in `%s'",

                                 name, value);

            }

            error = learn_parse_load_immediate(&imm, dst_value + 2, value, spec,

                                               ofpacts);

            if (error) {

                return error;

            }

        } else {

            struct ofpact_reg_move move;

            error = nxm_parse_reg_move(&move, value);

            if (error) {

                return error;

            }

            spec->n_bits = move.src.n_bits;

            spec->src_type = NX_LEARN_SRC_FIELD;

            spec->src = move.src;

            spec->dst_type = NX_LEARN_DST_LOAD;

            spec->dst = move.dst;

        }

    } else if (!strcmp(name, "output")) {

        error = mf_parse_subfield(&spec->src, value);

        if (error) {

            return error;

        }

        spec->n_bits = spec->src.n_bits;

        spec->src_type = NX_LEARN_SRC_FIELD;

        spec->dst_type = NX_LEARN_DST_OUTPUT;

    } else {

        return xasprintf("%s: unknown keyword %s", orig, name);

    }

    return NULL;

}

/* Returns NULL if successful, otherwise a malloc()'d string describing the

 * error.  The caller is responsible for freeing the returned string. */

static char * OVS_WARN_UNUSED_RESULT

learn_parse__(char *orig, char *arg, const struct ofputil_port_map *port_map,

              const struct ofputil_table_map *table_map,

              struct ofpbuf *ofpacts)

{

    struct ofpact_learn *learn;

    char *name, *value;

    learn = ofpact_put_LEARN(ofpacts);

    learn->idle_timeout = OFP_FLOW_PERMANENT;

    learn->hard_timeout = OFP_FLOW_PERMANENT;

    learn->priority = OFP_DEFAULT_PRIORITY;

    learn->table_id = 1;

    while (ofputil_parse_key_value(&arg, &name, &value)) {

        if (!strcmp(name, "table")) {

            if (!ofputil_table_from_string(value, table_map,

                                           &learn->table_id)) {

                return xasprintf("unknown table \"%s\"", value);

            } else if (learn->table_id == 255) {

                return xasprintf("%s: table id 255 not valid for `learn' "

                                 "action", orig);

            }

        } else if (!strcmp(name, "priority")) {

            learn->priority = atoi(value);

        } else if (!strcmp(name, "idle_timeout")) {

            learn->idle_timeout = atoi(value);

        } else if (!strcmp(name, "hard_timeout")) {

            learn->hard_timeout = atoi(value);

        } else if (!strcmp(name, "fin_idle_timeout")) {

            learn->fin_idle_timeout = atoi(value);

        } else if (!strcmp(name, "fin_hard_timeout")) {

            learn->fin_hard_timeout = atoi(value);

        } else if (!strcmp(name, "cookie")) {

            learn->cookie = htonll(strtoull(value, NULL, 0));

        } else if (!strcmp(name, "send_flow_rem")) {

            learn->flags |= NX_LEARN_F_SEND_FLOW_REM;

        } else if (!strcmp(name, "delete_learned")) {

            learn->flags |= NX_LEARN_F_DELETE_LEARNED;

        } else if (!strcmp(name, "limit")) {

            learn->limit = atoi(value);

        } else if (!strcmp(name, "result_dst")) {

            char *error;

            learn->flags |= NX_LEARN_F_WRITE_RESULT;

            error = mf_parse_subfield(&learn->result_dst, value);

            if (error) {

                return error;

            }

            if (!learn->result_dst.field->writable) {

                return xasprintf("%s is read-only", value);

            }

            if (learn->result_dst.n_bits != 1) {

                return xasprintf("result_dst in 'learn' action must be a "

                                 "single bit");

            }

        } else {

            struct ofpact_learn_spec *spec;

            char *error;

            spec = ofpbuf_put_zeros(ofpacts, sizeof *spec);

            error = learn_parse_spec(orig, name, value, port_map,

                                     spec, ofpacts);

            if (error) {

                return error;

            }

            learn = ofpacts->header;

        }

    }

    if (ofpbuf_oversized(ofpacts)) {

        return xasprintf("input too big");

    }

    ofpact_finish_LEARN(ofpacts, &learn);

    return NULL;

}

/* Parses 'arg' as a set of arguments to the "learn" action and appends a

 * matching OFPACT_LEARN action to 'ofpacts'.  ovs-actions(7) describes the

 * format parsed.

 *

 * Returns NULL if successful, otherwise a malloc()'d string describing the

 * error.  The caller is responsible for freeing the returned string.

 *

 * If 'flow' is nonnull, then it should be the flow from a struct match that is

 * the matching rule for the learning action.  This helps to better validate

 * the action's arguments.

 *

 * Modifies 'arg'. */

char * OVS_WARN_UNUSED_RESULT

learn_parse(char *arg, const struct ofputil_port_map *port_map,

            const struct ofputil_table_map *table_map,

            struct ofpbuf *ofpacts)

{

    char *orig = xstrdup(arg);

    char *error = learn_parse__(orig, arg, port_map, table_map, ofpacts);

    free(orig);

    return error;

}

/* Appends a description of 'learn' to 's', in the format that ovs-actions(7)

 * describes. */

void

learn_format(const struct ofpact_learn *learn,

             const struct ofputil_port_map *port_map,

             const struct ofputil_table_map *table_map,

             struct ds *s)

{

    const struct ofpact_learn_spec *spec;

    struct match match;

    match_init_catchall(&match);

    ds_put_format(s, "%slearn(%s%stable=%s",

                  colors.learn, colors.end, colors.special, colors.end);

    ofputil_format_table(learn->table_id, table_map, s);

    if (learn->idle_timeout != OFP_FLOW_PERMANENT) {

        ds_put_format(s, ",%sidle_timeout=%s%"PRIu16,

                      colors.param, colors.end, learn->idle_timeout);

    }

    if (learn->hard_timeout != OFP_FLOW_PERMANENT) {

        ds_put_format(s, ",%shard_timeout=%s%"PRIu16,

                      colors.param, colors.end, learn->hard_timeout);

    }

    if (learn->fin_idle_timeout) {

        ds_put_format(s, ",%sfin_idle_timeout=%s%"PRIu16,

                      colors.param, colors.end, learn->fin_idle_timeout);

    }

    if (learn->fin_hard_timeout) {

        ds_put_format(s, "%s,fin_hard_timeout=%s%"PRIu16,

                      colors.param, colors.end, learn->fin_hard_timeout);

    }

    if (learn->priority != OFP_DEFAULT_PRIORITY) {

        ds_put_format(s, "%s,priority=%s%"PRIu16,

                      colors.special, colors.end, learn->priority);

    }

    if (learn->flags & NX_LEARN_F_SEND_FLOW_REM) {

        ds_put_format(s, ",%ssend_flow_rem%s", colors.value, colors.end);

    }

    if (learn->flags & NX_LEARN_F_DELETE_LEARNED) {

        ds_put_format(s, ",%sdelete_learned%s", colors.value, colors.end);

    }

    if (learn->cookie != 0) {

        ds_put_format(s, ",%scookie=%s%#"PRIx64,

                      colors.param, colors.end, ntohll(learn->cookie));

    }

    if (learn->limit != 0) {

        ds_put_format(s, ",%slimit=%s%"PRIu32,

                      colors.param, colors.end, learn->limit);

    }

    if (learn->flags & NX_LEARN_F_WRITE_RESULT) {

        ds_put_format(s, ",%sresult_dst=%s", colors.param, colors.end);

        mf_format_subfield(&learn->result_dst, s);

    }

    OFPACT_LEARN_SPEC_FOR_EACH (spec, learn) {

        unsigned int n_bytes = DIV_ROUND_UP(spec->n_bits, 8);

        ds_put_char(s, ',');

        switch (spec->src_type | spec->dst_type) {

        case NX_LEARN_SRC_IMMEDIATE | NX_LEARN_DST_MATCH: {

            if (spec->dst.ofs == 0

                && spec->dst.n_bits == spec->dst.field->n_bits) {

                union mf_value value;

                memset(&value, 0, sizeof value);

                memcpy(&value.b[spec->dst.field->n_bytes - n_bytes],

                       ofpact_learn_spec_imm(spec), n_bytes);

                ds_put_format(s, "%s%s=%s", colors.param,

                              spec->dst.field->name, colors.end);

                mf_format(spec->dst.field, &value, NULL, port_map, s);

            } else {

                ds_put_format(s, "%s", colors.param);

                mf_format_subfield(&spec->dst, s);

                ds_put_format(s, "=%s", colors.end);

                ds_put_hex(s, ofpact_learn_spec_imm(spec), n_bytes);

            }

            break;

        }

        case NX_LEARN_SRC_FIELD | NX_LEARN_DST_MATCH:

            ds_put_format(s, "%s", colors.param);

            mf_format_subfield(&spec->dst, s);

            ds_put_format(s, "%s", colors.end);

            if (spec->src.field != spec->dst.field ||

                spec->src.ofs != spec->dst.ofs) {

                ds_put_format(s, "%s=%s", colors.param, colors.end);

                mf_format_subfield(&spec->src, s);

            }

            break;

        case NX_LEARN_SRC_IMMEDIATE | NX_LEARN_DST_LOAD:

            ds_put_format(s, "%sload:%s", colors.special, colors.end);

            ds_put_hex(s, ofpact_learn_spec_imm(spec), n_bytes);

            ds_put_format(s, "%s->%s", colors.special, colors.end);

            mf_format_subfield(&spec->dst, s);

            break;

        case NX_LEARN_SRC_FIELD | NX_LEARN_DST_LOAD:

            ds_put_format(s, "%sload:%s", colors.special, colors.end);

            mf_format_subfield(&spec->src, s);

            ds_put_format(s, "%s->%s", colors.special, colors.end);

            mf_format_subfield(&spec->dst, s);

            break;

        case NX_LEARN_SRC_FIELD | NX_LEARN_DST_OUTPUT:

            ds_put_format(s, "%soutput:%s", colors.special, colors.end);

            mf_format_subfield(&spec->src, s);

            break;

        }

    }

    ds_put_format(s, "%s)%s", colors.learn, colors.end);

}