ofp-util: Add more functions for supporting OpenFlow error codes.

[mirror_ovs.git] / lib / ofp-util.h

/*
 * Copyright (c) 2008, 2009, 2010 Nicira Networks.
 *
 * 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 OFP_UTIL_H
#define OFP_UTIL_H 1

#include <assert.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include "flow.h"

struct ofpbuf;
struct ofp_action_header;

/* OpenFlow protocol utility functions. */
void *make_openflow(size_t openflow_len, uint8_t type, struct ofpbuf **);
void *make_openflow_xid(size_t openflow_len, uint8_t type,
                        uint32_t xid, struct ofpbuf **);
void *put_openflow(size_t openflow_len, uint8_t type, struct ofpbuf *);
void *put_openflow_xid(size_t openflow_len, uint8_t type, uint32_t xid,
                       struct ofpbuf *);
void update_openflow_length(struct ofpbuf *);
struct ofpbuf *make_flow_mod(uint16_t command, const struct flow *,
                             size_t actions_len);
struct ofpbuf *make_add_flow(const struct flow *, uint32_t buffer_id,
                             uint16_t max_idle, size_t actions_len);
struct ofpbuf *make_del_flow(const struct flow *);
struct ofpbuf *make_add_simple_flow(const struct flow *,
                                    uint32_t buffer_id, uint16_t out_port,
                                    uint16_t max_idle);
struct ofpbuf *make_packet_in(uint32_t buffer_id, uint16_t in_port,
                              uint8_t reason,
                              const struct ofpbuf *payload, int max_send_len);
struct ofpbuf *make_packet_out(const struct ofpbuf *packet, uint32_t buffer_id,
                               uint16_t in_port,
                               const struct ofp_action_header *,
                               size_t n_actions);
struct ofpbuf *make_buffered_packet_out(uint32_t buffer_id,
                                        uint16_t in_port, uint16_t out_port);
struct ofpbuf *make_unbuffered_packet_out(const struct ofpbuf *packet,
                                          uint16_t in_port, uint16_t out_port);
struct ofpbuf *make_echo_request(void);
struct ofpbuf *make_echo_reply(const struct ofp_header *rq);
int check_ofp_message(const struct ofp_header *, uint8_t type, size_t size);
int check_ofp_message_array(const struct ofp_header *, uint8_t type,
                            size_t size, size_t array_elt_size,
                            size_t *n_array_elts);
int check_ofp_packet_out(const struct ofp_header *, struct ofpbuf *data,
                         int *n_actions, int max_ports);

struct flow_stats_iterator {
    const uint8_t *pos, *end;
};
const struct ofp_flow_stats *flow_stats_first(struct flow_stats_iterator *,
                                              const struct ofp_stats_reply *);
const struct ofp_flow_stats *flow_stats_next(struct flow_stats_iterator *);

struct actions_iterator {
    const union ofp_action *pos, *end;
};
const union ofp_action *actions_first(struct actions_iterator *,
                                      const union ofp_action *,
                                      size_t n_actions);
const union ofp_action *actions_next(struct actions_iterator *);
int validate_actions(const union ofp_action *, size_t n_actions,
                     int max_ports);
bool action_outputs_to_port(const union ofp_action *, uint16_t port);

void normalize_match(struct ofp_match *);
char *ofp_match_to_literal_string(const struct ofp_match *match);
\f
/* OpenFlow errors.
 *
 * OpenFlow errors have two 16-bit parts: a "type" and a "code".  A "type" has
 * a unique meaning.  The "code" values are different for each "type".
 *
 * We embed OpenFlow errors in the same space as errno values by shifting
 * 'type' left 16 bits and adding the 'code'.  An "int" value is thus broken
 * into a few different ranges:
 *
 *      - 0: success.
 *
 *      - 1...65535: system errno values.
 *
 *        The assumption that system errno values are less than 65536 is true
 *        on at least Linux, FreeBSD, OpenBSD, and Windows.  RFC 1813 defines
 *        NFSv3-specific errno codes starting at 10000, another hint that this
 *        is a reasonable assumption.
 *
 *        C and POSIX say that errno values are positive.
 *
 *      - 65536...INT_MAX: OpenFlow errors.
 *
 *        In OpenFlow, a "type" of 0 is valid, but it corresponds to
 *        OFPET_HELLO_FAILED.  That's not a general-purpose error: only the
 *        vconn library would ever care to send it.  So we ignore it.
 *
 *      - negative values: not used.
 */

/* Returns the OpenFlow error with the specified 'type' and 'code' as an
 * integer. */
static inline int
ofp_mkerr(uint16_t type, uint16_t code)
{
    assert(type > 0 && type <= 0x7fff);
    return (type << 16) | code;
}

/* Returns true if 'error' is in the range of values used as OpenFlow error
 * codes as explained above. */
static inline bool
is_ofp_error(int error)
{
    return error >= 0x10000;
}

/* Returns true if 'error' appears to be a system errno value. */
static inline bool
is_errno(int error)
{
    return error < 0x10000;
}

/* Returns the "type" part of the OpenFlow error code 'error' (which must be in
 * the format explained above). */
static inline uint16_t
get_ofp_err_type(int error)
{
    return error >> 16;
}

/* Returns the "code" part of the OpenFlow error code 'error' (which must be in
 * the format explained above). */
static inline uint16_t
get_ofp_err_code(int error)
{
    return error & 0xffff;
}

#endif /* ofp-util.h */