mirror of
https://github.com/openvswitch/ovs
synced 2025-08-29 05:18:13 +00:00
ce523f65fc
This patch simplifies the API of nxm_dst_check() and adds a new function nxm_src_check() for checking source fields.
261 lines
7.6 KiB
C
261 lines
7.6 KiB
C
/*
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* Copyright (c) 2010, 2011 Nicira Networks.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include "multipath.h"
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#include <arpa/inet.h>
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#include <inttypes.h>
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#include <sys/types.h>
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#include <netinet/in.h>
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#include "dynamic-string.h"
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#include "nx-match.h"
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#include "ofp-util.h"
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#include "openflow/nicira-ext.h"
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#include "packets.h"
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#include "vlog.h"
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VLOG_DEFINE_THIS_MODULE(multipath);
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static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
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/* multipath_check(). */
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int
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multipath_check(const struct nx_action_multipath *mp, const struct flow *flow)
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{
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uint32_t n_links = ntohs(mp->max_link) + 1;
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size_t min_n_bits = log_2_floor(n_links) + 1;
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int ofs = nxm_decode_ofs(mp->ofs_nbits);
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int n_bits = nxm_decode_n_bits(mp->ofs_nbits);
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int error;
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error = nxm_dst_check(mp->dst, ofs, n_bits, flow);
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if (error) {
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return error;
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}
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if (!flow_hash_fields_valid(ntohs(mp->fields))) {
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VLOG_WARN_RL(&rl, "unsupported fields %"PRIu16, ntohs(mp->fields));
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} else if (mp->algorithm != htons(NX_MP_ALG_MODULO_N)
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&& mp->algorithm != htons(NX_MP_ALG_HASH_THRESHOLD)
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&& mp->algorithm != htons(NX_MP_ALG_HRW)
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&& mp->algorithm != htons(NX_MP_ALG_ITER_HASH)) {
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VLOG_WARN_RL(&rl, "unsupported algorithm %"PRIu16,
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ntohs(mp->algorithm));
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} else if (n_bits < min_n_bits) {
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VLOG_WARN_RL(&rl, "multipath action requires at least %zu bits for "
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"%"PRIu32" links", min_n_bits, n_links);
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} else {
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return 0;
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}
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return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_ARGUMENT);
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}
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/* multipath_execute(). */
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static uint16_t multipath_algorithm(uint32_t hash, enum nx_mp_algorithm,
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unsigned int n_links, unsigned int arg);
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void
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multipath_execute(const struct nx_action_multipath *mp, struct flow *flow)
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{
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/* Calculate value to store. */
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uint32_t hash = flow_hash_fields(flow, ntohs(mp->fields),
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ntohs(mp->basis));
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uint16_t link = multipath_algorithm(hash, ntohs(mp->algorithm),
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ntohs(mp->max_link) + 1,
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ntohl(mp->arg));
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nxm_reg_load(mp->dst, mp->ofs_nbits, link, flow);
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}
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static uint16_t
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algorithm_hrw(uint32_t hash, unsigned int n_links)
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{
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uint32_t best_weight;
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uint16_t best_link;
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unsigned int link;
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best_link = 0;
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best_weight = hash_2words(hash, 0);
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for (link = 1; link < n_links; link++) {
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uint32_t weight = hash_2words(hash, link);
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if (weight > best_weight) {
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best_link = link;
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best_weight = weight;
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}
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}
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return best_link;
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}
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/* Works for 'x' in the range [1,65536], which is all we need. */
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static unsigned int
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round_up_pow2(unsigned int x)
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{
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x--;
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x |= x >> 1;
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x |= x >> 2;
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x |= x >> 4;
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x |= x >> 8;
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return x + 1;
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}
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static uint16_t
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algorithm_iter_hash(uint32_t hash, unsigned int n_links, unsigned int modulo)
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{
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uint16_t link;
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int i;
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if (modulo < n_links || modulo / 2 > n_links) {
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modulo = round_up_pow2(n_links);
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}
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i = 0;
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do {
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link = hash_2words(hash, i++) % modulo;
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} while (link >= n_links);
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return link;
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}
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static uint16_t
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multipath_algorithm(uint32_t hash, enum nx_mp_algorithm algorithm,
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unsigned int n_links, unsigned int arg)
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{
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switch (algorithm) {
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case NX_MP_ALG_MODULO_N:
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return hash % n_links;
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case NX_MP_ALG_HASH_THRESHOLD:
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if (n_links == 1) {
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return 0;
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}
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return hash / (UINT32_MAX / n_links + 1);
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case NX_MP_ALG_HRW:
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return (n_links <= 64
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? algorithm_hrw(hash, n_links)
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: algorithm_iter_hash(hash, n_links, 0));
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case NX_MP_ALG_ITER_HASH:
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return algorithm_iter_hash(hash, n_links, arg);
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}
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NOT_REACHED();
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}
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/* multipath_parse(). */
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void
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multipath_parse(struct nx_action_multipath *mp, const char *s_)
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{
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char *s = xstrdup(s_);
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char *save_ptr = NULL;
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char *fields, *basis, *algorithm, *n_links_str, *arg, *dst;
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uint32_t header;
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int ofs, n_bits;
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int n_links;
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fields = strtok_r(s, ", ", &save_ptr);
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basis = strtok_r(NULL, ", ", &save_ptr);
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algorithm = strtok_r(NULL, ", ", &save_ptr);
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n_links_str = strtok_r(NULL, ", ", &save_ptr);
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arg = strtok_r(NULL, ", ", &save_ptr);
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dst = strtok_r(NULL, ", ", &save_ptr);
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if (!dst) {
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ovs_fatal(0, "%s: not enough arguments to multipath action", s_);
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}
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memset(mp, 0, sizeof *mp);
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mp->type = htons(OFPAT_VENDOR);
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mp->len = htons(sizeof *mp);
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mp->vendor = htonl(NX_VENDOR_ID);
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mp->subtype = htons(NXAST_MULTIPATH);
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if (!strcasecmp(fields, "eth_src")) {
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mp->fields = htons(NX_HASH_FIELDS_ETH_SRC);
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} else if (!strcasecmp(fields, "symmetric_l4")) {
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mp->fields = htons(NX_HASH_FIELDS_SYMMETRIC_L4);
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} else {
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ovs_fatal(0, "%s: unknown fields `%s'", s_, fields);
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}
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mp->basis = htons(atoi(basis));
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if (!strcasecmp(algorithm, "modulo_n")) {
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mp->algorithm = htons(NX_MP_ALG_MODULO_N);
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} else if (!strcasecmp(algorithm, "hash_threshold")) {
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mp->algorithm = htons(NX_MP_ALG_HASH_THRESHOLD);
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} else if (!strcasecmp(algorithm, "hrw")) {
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mp->algorithm = htons(NX_MP_ALG_HRW);
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} else if (!strcasecmp(algorithm, "iter_hash")) {
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mp->algorithm = htons(NX_MP_ALG_ITER_HASH);
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} else {
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ovs_fatal(0, "%s: unknown algorithm `%s'", s_, algorithm);
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}
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n_links = atoi(n_links_str);
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if (n_links < 1 || n_links > 65536) {
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ovs_fatal(0, "%s: n_links %d is not in valid range 1 to 65536",
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s_, n_links);
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}
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mp->max_link = htons(n_links - 1);
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mp->arg = htonl(atoi(arg));
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nxm_parse_field_bits(dst, &header, &ofs, &n_bits);
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if (n_bits < 16 && n_links > (1u << n_bits)) {
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ovs_fatal(0, "%s: %d-bit destination field has %u possible values, "
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"less than specified n_links %d",
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s_, n_bits, 1u << n_bits, n_links);
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}
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mp->ofs_nbits = nxm_encode_ofs_nbits(ofs, n_bits);
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mp->dst = htonl(header);
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free(s);
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}
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void
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multipath_format(const struct nx_action_multipath *mp, struct ds *s)
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{
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const char *fields, *algorithm;
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uint16_t mp_fields = ntohs(mp->fields);
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uint16_t mp_algorithm = ntohs(mp->algorithm);
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fields = flow_hash_fields_to_str(mp_fields);
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switch ((enum nx_mp_algorithm) mp_algorithm) {
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case NX_MP_ALG_MODULO_N:
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algorithm = "modulo_n";
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break;
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case NX_MP_ALG_HASH_THRESHOLD:
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algorithm = "hash_threshold";
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break;
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case NX_MP_ALG_HRW:
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algorithm = "hrw";
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break;
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case NX_MP_ALG_ITER_HASH:
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algorithm = "iter_hash";
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break;
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default:
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algorithm = "<unknown>";
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}
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ds_put_format(s, "multipath(%s,%"PRIu16",%s,%d,%"PRIu16",",
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fields, ntohs(mp->basis), algorithm, ntohs(mp->max_link) + 1,
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ntohl(mp->arg));
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nxm_format_field_bits(s, ntohl(mp->dst), nxm_decode_ofs(mp->ofs_nbits),
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nxm_decode_n_bits(mp->ofs_nbits));
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ds_put_char(s, ')');
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}
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