/*

 * Copyright (c) 2012, 2013, 2014, 2015, 2016 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 <errno.h>

#include "byte-order.h"

#include "openflow/openflow.h"

#include "openflow/nicira-ext.h"

#include "openvswitch/dynamic-string.h"

#include "openvswitch/ofp-actions.h"

#include "openvswitch/ofp-errors.h"

#include "openvswitch/ofp-msgs.h"

#include "openvswitch/ofp-print.h"

#include "openvswitch/ofpbuf.h"

#include "openvswitch/vlog.h"

#include "util.h"

VLOG_DEFINE_THIS_MODULE(ofp_errors);

struct triplet {

    uint32_t vendor;

    int type, code;

};

#include "ofp-errors.inc"

/* Returns an ofperr_domain that corresponds to the OpenFlow version number

 * 'version' (one of the possible values of struct ofp_header's 'version'

 * member).  Returns NULL if the version isn't defined or isn't understood by

 * OVS. */

static const struct ofperr_domain *

ofperr_domain_from_version(enum ofp_version version)

{

    switch (version) {

    case OFP10_VERSION:

        return &ofperr_of10;

    case OFP11_VERSION:

        return &ofperr_of11;

    case OFP12_VERSION:

        return &ofperr_of12;

    case OFP13_VERSION:

        return &ofperr_of13;

    case OFP14_VERSION:

        return &ofperr_of14;

    case OFP15_VERSION:

        return &ofperr_of15;

    default:

        return NULL;

    }

}

/* Returns the name (e.g. "OpenFlow 1.0") of OpenFlow version 'version'. */

const char *

ofperr_domain_get_name(enum ofp_version version)

{

    const struct ofperr_domain *domain = ofperr_domain_from_version(version);

    return domain ? domain->name : NULL;

}

/* Returns true if 'error' is a valid OFPERR_* value, false otherwise. */

bool

ofperr_is_valid(enum ofperr error)

{

    return error >= OFPERR_OFS && error < OFPERR_OFS + OFPERR_N_ERRORS;

}

/* Returns the OFPERR_* value that corresponds to 'type' and 'code' within

 * 'version', or 0 if either no such OFPERR_* value exists or 'version' is

 * unknown. */

static enum ofperr

ofperr_decode(enum ofp_version version,

              uint32_t vendor, uint16_t type, uint16_t code)

{

    const struct ofperr_domain *domain = ofperr_domain_from_version(version);

    return domain ? domain->decode(vendor, type, code) : 0;

}

/* Returns the name of 'error', e.g. "OFPBRC_BAD_TYPE" if 'error' is

 * OFPBRC_BAD_TYPE, or "<invalid>" if 'error' is not a valid OFPERR_* value.

 *

 * Consider ofperr_to_string() instead, if the error code might be an errno

 * value. */

const char *

ofperr_get_name(enum ofperr error)

{

    return (ofperr_is_valid(error)

            ? error_names[error - OFPERR_OFS]

            : "<invalid>");

}

/* Returns the OFPERR_* value that corresponds for 'name', 0 if none exists.

 * For example, returns OFPERR_OFPHFC_INCOMPATIBLE if 'name' is

 * "OFPHFC_INCOMPATIBLE".

 *

 * This is probably useful only for debugging and testing. */

enum ofperr

ofperr_from_name(const char *name)

{

    int i;

    for (i = 0; i < OFPERR_N_ERRORS; i++) {

        if (!strcmp(name, error_names[i])) {

            return i + OFPERR_OFS;

        }

    }

    return 0;

}

/* Returns an extended description name of 'error', e.g. "ofp_header.type not

 * supported." if 'error' is OFPBRC_BAD_TYPE, or "<invalid>" if 'error' is not

 * a valid OFPERR_* value. */

const char *

ofperr_get_description(enum ofperr error)

{

    return (ofperr_is_valid(error)

            ? error_comments[error - OFPERR_OFS]

            : "<invalid>");

}

static const struct triplet *

ofperr_get_triplet__(enum ofperr error, const struct ofperr_domain *domain)

{

    size_t ofs = error - OFPERR_OFS;

    ovs_assert(ofperr_is_valid(error));

    return &domain->errors[ofs];

}

static struct ofpbuf *

ofperr_encode_msg__(enum ofperr error, enum ofp_version ofp_version,

                    ovs_be32 xid, const void *data, size_t data_len)

{

    static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);

    const struct ofperr_domain *domain;

    const struct triplet *triplet;

    struct ofp_error_msg *oem;

    struct ofpbuf *buf;

    /* Get the error domain for 'ofp_version', or fall back to OF1.0. */

    domain = ofperr_domain_from_version(ofp_version);

    if (!domain) {

        VLOG_ERR_RL(&rl, "cannot encode error for unknown OpenFlow "

                    "version 0x%02x", ofp_version);

        domain = &ofperr_of10;

    }

    /* Make sure 'error' is valid in 'domain', or use a fallback error. */

    if (!ofperr_is_valid(error)) {

        /* 'error' seems likely to be a system errno value. */

        VLOG_ERR_RL(&rl, "invalid OpenFlow error code %d (%s)",

                    error, ovs_strerror(error));

        error = OFPERR_NXBRC_UNENCODABLE_ERROR;

    } else if (domain->errors[error - OFPERR_OFS].code < 0) {

        VLOG_ERR_RL(&rl, "cannot encode %s for %s",

                    ofperr_get_name(error), domain->name);

        error = OFPERR_NXBRC_UNENCODABLE_ERROR;

    }

    triplet = ofperr_get_triplet__(error, domain);

    if (!triplet->vendor) {

        buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,

                               sizeof *oem + data_len);

        oem = ofpbuf_put_uninit(buf, sizeof *oem);

        oem->type = htons(triplet->type);

        oem->code = htons(triplet->code);

    } else if (ofp_version <= OFP11_VERSION) {

        struct nx_vendor_error *nve;

        buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,

                               sizeof *oem + sizeof *nve + data_len);

        oem = ofpbuf_put_uninit(buf, sizeof *oem);

        oem->type = htons(NXET_VENDOR);

        oem->code = htons(NXVC_VENDOR_ERROR);

        nve = ofpbuf_put_uninit(buf, sizeof *nve);

        nve->vendor = htonl(triplet->vendor);

        nve->type = htons(triplet->type);

        nve->code = htons(triplet->code);

    } else {

        ovs_be32 vendor = htonl(triplet->vendor);

        buf = ofpraw_alloc_xid(OFPRAW_OFPT_ERROR, domain->version, xid,

                               sizeof *oem + sizeof(uint32_t) + data_len);

        oem = ofpbuf_put_uninit(buf, sizeof *oem);

        oem->type = htons(OFPET12_EXPERIMENTER);

        oem->code = htons(triplet->type);

        ofpbuf_put(buf, &vendor, sizeof vendor);

    }

    ofpbuf_put(buf, data, MIN(data_len, UINT16_MAX - buf->size));

    ofpmsg_update_length(buf);

    return buf;

}

/* Creates and returns an OpenFlow message of type OFPT_ERROR that conveys the

 * given 'error'.

 *

 * 'oh->version' determines the OpenFlow version of the error reply.

 * 'oh->xid' determines the xid of the error reply.

 * The error reply will contain an initial subsequence of 'oh', up to

 * 'oh->length' (or however much fits).

 *

 * This function isn't appropriate for encoding OFPET_HELLO_FAILED error

 * messages.  Use ofperr_encode_hello() instead. */

struct ofpbuf *

ofperr_encode_reply(enum ofperr error, const struct ofp_header *oh)

{

    return ofperr_encode_msg__(error, oh->version, oh->xid,

                               oh, ntohs(oh->length));

}

/* Creates and returns an OpenFlow message of type OFPT_ERROR that conveys the

 * given 'error', in the error domain 'domain'.  The error message will include

 * the additional null-terminated text string 's'.

 *

 * If 'version' is an unknown version then OFP10_VERSION is used.

 * OFPET_HELLO_FAILED error messages are supposed to be backward-compatible,

 * so in theory this should work. */

struct ofpbuf *

ofperr_encode_hello(enum ofperr error, enum ofp_version ofp_version,

                    const char *s)

{

    return ofperr_encode_msg__(error, ofp_version, htonl(0), s, strlen(s));

}

void

ofperr_msg_format(struct ds *string, enum ofperr error,

                  const struct ofpbuf *payload,

                  const struct ofputil_port_map *port_map,

                  const struct ofputil_table_map *table_map)

{

    ds_put_format(string, " %s\n", ofperr_get_name(error));

    if (error == OFPERR_OFPHFC_INCOMPATIBLE || error == OFPERR_OFPHFC_EPERM) {

        ds_put_printable(string, payload->data, payload->size);

    } else {

        char *s = ofp_to_string(payload->data, payload->size,

                                port_map, table_map, 1);

        ds_put_cstr(string, s);

        free(s);

    }

}

int

ofperr_get_vendor(enum ofperr error, enum ofp_version version)

{

    const struct ofperr_domain *domain = ofperr_domain_from_version(version);

    return domain ? ofperr_get_triplet__(error, domain)->vendor : -1;

}

/* Returns the value that would go into an OFPT_ERROR message's 'type' for

 * encoding 'error' in 'domain'.  Returns -1 if 'error' is not encodable in

 * 'version' or 'version' is unknown.

 *

 * 'error' must be a valid OFPERR_* code, as checked by ofperr_is_valid(). */

int

ofperr_get_type(enum ofperr error, enum ofp_version version)

{

    const struct ofperr_domain *domain = ofperr_domain_from_version(version);

    return domain ? ofperr_get_triplet__(error, domain)->type : -1;

}

/* Returns the value that would go into an OFPT_ERROR message's 'code' for

 * encoding 'error' in 'domain'.  Returns -1 if 'error' is not encodable in

 * 'version', 'version' is unknown or if 'error' represents a category

 * rather than a specific error.

 *

 *

 * 'error' must be a valid OFPERR_* code, as checked by ofperr_is_valid(). */

int

ofperr_get_code(enum ofperr error, enum ofp_version version)

{

    const struct ofperr_domain *domain = ofperr_domain_from_version(version);

    return domain ? ofperr_get_triplet__(error, domain)->code : -1;

}

/* Tries to decode 'oh', which should be an OpenFlow OFPT_ERROR message.

 * Returns an OFPERR_* constant on success, 0 on failure.

 *

 * If 'payload' is nonnull, on success '*payload' is initialized with a copy of

 * the error's payload (copying is required because the payload is not properly

 * aligned).  The caller must free the payload (with ofpbuf_uninit()) when it

 * is no longer needed.  On failure, '*payload' is cleared. */

enum ofperr

ofperr_decode_msg(const struct ofp_header *oh, struct ofpbuf *payload)

{

    const struct ofp_error_msg *oem;

    enum ofpraw raw;

    uint16_t type, code;

    uint32_t vendor;

    if (payload) {

        memset(payload, 0, sizeof *payload);

    }

    /* Pull off the error message. */

    struct ofpbuf b = ofpbuf_const_initializer(oh, ntohs(oh->length));

    enum ofperr error = ofpraw_pull(&raw, &b);

    if (error) {

        return 0;

    }

    oem = ofpbuf_pull(&b, sizeof *oem);

    /* Get the error type and code. */

    vendor = 0;

    type = ntohs(oem->type);

    code = ntohs(oem->code);

    if (type == NXET_VENDOR && code == NXVC_VENDOR_ERROR) {

        const struct nx_vendor_error *nve = ofpbuf_try_pull(&b, sizeof *nve);

        if (!nve) {

            return 0;

        }

        vendor = ntohl(nve->vendor);

        type = ntohs(nve->type);

        code = ntohs(nve->code);

    } else if (type == OFPET12_EXPERIMENTER) {

        const ovs_be32 *vendorp = ofpbuf_try_pull(&b, sizeof *vendorp);

        if (!vendorp) {

            return 0;

        }

        vendor = ntohl(*vendorp);

        type = code;

        code = 0;

    }

    /* Translate the error type and code into an ofperr. */

    error = ofperr_decode(oh->version, vendor, type, code);

    if (error && payload) {

        ofpbuf_init(payload, b.size);

        ofpbuf_push(payload, b.data, b.size);

        ofpbuf_trim(payload);

    }

    return error;

}

/* If 'error' is a valid OFPERR_* value, returns its name

 * (e.g. "OFPBRC_BAD_TYPE" for OFPBRC_BAD_TYPE).  Otherwise, assumes that

 * 'error' is a positive errno value and returns what ovs_strerror() produces

 * for 'error'.  */

const char *

ofperr_to_string(enum ofperr error)

{

    return (ofperr_is_valid(error)

            ? ofperr_get_name(error)

            : ovs_strerror(error));

}