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/*
* Copyright (c) 2011, 2012 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 "dynamic-string.h"
#include "meta-flow.h"
#include "nx-match.h"
#include "ofp-actions.h"
#include "ofp-errors.h"
#include "ofp-util.h"
#include "ofpbuf.h"
#include "openflow/openflow.h"
#include "unaligned.h"
static ovs_be16
get_be16(const void **pp)
{
const ovs_be16 *p = *pp;
ovs_be16 value = *p;
*pp = p + 1;
return value;
}
static ovs_be32
get_be32(const void **pp)
{
const ovs_be32 *p = *pp;
ovs_be32 value = get_unaligned_be32(p);
*pp = p + 1;
return value;
}
static void
get_subfield(int n_bits, const void **p, struct mf_subfield *sf)
{
sf->field = mf_from_nxm_header(ntohl(get_be32(p)));
sf->ofs = ntohs(get_be16(p));
sf->n_bits = n_bits;
}
static unsigned int
learn_min_len(uint16_t header)
{
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;
unsigned int min_len;
min_len = 0;
if (src_type == NX_LEARN_SRC_FIELD) {
min_len += sizeof(ovs_be32); /* src_field */
min_len += sizeof(ovs_be16); /* src_ofs */
} else {
min_len += DIV_ROUND_UP(n_bits, 16);
}
if (dst_type == NX_LEARN_DST_MATCH ||
dst_type == NX_LEARN_DST_LOAD) {
min_len += sizeof(ovs_be32); /* dst_field */
min_len += sizeof(ovs_be16); /* dst_ofs */
}
return min_len;
}
/* Converts 'nal' into a "struct ofpact_learn" and appends that struct to
* 'ofpacts'. Returns 0 if successful, otherwise an OFPERR_*. */
enum ofperr
learn_from_openflow(const struct nx_action_learn *nal, struct ofpbuf *ofpacts)
{
struct ofpact_learn *learn;
const void *p, *end;
if (nal->pad) {
return OFPERR_OFPBAC_BAD_ARGUMENT;
}
learn = ofpact_put_LEARN(ofpacts);
learn->idle_timeout = ntohs(nal->idle_timeout);
learn->hard_timeout = ntohs(nal->hard_timeout);
learn->priority = ntohs(nal->priority);
learn->cookie = ntohll(nal->cookie);
learn->flags = ntohs(nal->flags);
learn->table_id = nal->table_id;
learn->fin_idle_timeout = ntohs(nal->fin_idle_timeout);
learn->fin_hard_timeout = ntohs(nal->fin_hard_timeout);
if (learn->flags & ~OFPFF_SEND_FLOW_REM || learn->table_id == 0xff) {
return OFPERR_OFPBAC_BAD_ARGUMENT;
}
end = (char *) nal + ntohs(nal->len);
for (p = nal + 1; p != end; ) {
struct ofpact_learn_spec *spec;
uint16_t header = ntohs(get_be16(&p));
if (!header) {
break;
}
spec = ofpbuf_put_zeros(ofpacts, sizeof *spec);
learn = ofpacts->l2;
learn->n_specs++;
spec->src_type = header & NX_LEARN_SRC_MASK;
spec->dst_type = header & NX_LEARN_DST_MASK;
spec->n_bits = header & NX_LEARN_N_BITS_MASK;
/* Check for valid src and dst type combination. */
if (spec->dst_type == NX_LEARN_DST_MATCH ||
spec->dst_type == NX_LEARN_DST_LOAD ||
(spec->dst_type == NX_LEARN_DST_OUTPUT &&
spec->src_type == NX_LEARN_SRC_FIELD)) {
/* OK. */
} else {
return OFPERR_OFPBAC_BAD_ARGUMENT;
}
/* Check that the arguments don't overrun the end of the action. */
if ((char *) end - (char *) p < learn_min_len(header)) {
return OFPERR_OFPBAC_BAD_LEN;
}
/* Get the source. */
if (spec->src_type == NX_LEARN_SRC_FIELD) {
get_subfield(spec->n_bits, &p, &spec->src);
} else {
int p_bytes = 2 * DIV_ROUND_UP(spec->n_bits, 16);
bitwise_copy(p, p_bytes, 0,
&spec->src_imm, sizeof spec->src_imm, 0,
spec->n_bits);
p = (const uint8_t *) p + p_bytes;
}
/* Get the destination. */
if (spec->dst_type == NX_LEARN_DST_MATCH ||
spec->dst_type == NX_LEARN_DST_LOAD) {
get_subfield(spec->n_bits, &p, &spec->dst);
}
}
ofpact_update_len(ofpacts, &learn->ofpact);
if (!is_all_zeros(p, (char *) end - (char *) p)) {
return OFPERR_OFPBAC_BAD_ARGUMENT;
}
return 0;
}
/* 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 flow *flow)
{
const struct ofpact_learn_spec *spec;
struct cls_rule rule;
cls_rule_init_catchall(&rule, 0);
for (spec = learn->specs; spec < &learn->specs[learn->n_specs]; spec++) {
enum ofperr error;
/* Check the source. */
if (spec->src_type == NX_LEARN_SRC_FIELD) {
error = mf_check_src(&spec->src, flow);
if (error) {
return error;
}
}
/* Check the destination. */
switch (spec->dst_type) {
case NX_LEARN_DST_MATCH:
error = mf_check_src(&spec->dst, &rule.flow);
if (error) {
return error;
}
mf_write_subfield(&spec->dst, &spec->src_imm, &rule);
break;
case NX_LEARN_DST_LOAD:
error = mf_check_dst(&spec->dst, &rule.flow);
if (error) {
return error;
}
break;
case NX_LEARN_DST_OUTPUT:
/* Nothing to do. */
break;
}
}
return 0;
}
static void
put_be16(struct ofpbuf *b, ovs_be16 x)
{
ofpbuf_put(b, &x, sizeof x);
}
static void
put_be32(struct ofpbuf *b, ovs_be32 x)
{
ofpbuf_put(b, &x, sizeof x);
}
static void
put_u16(struct ofpbuf *b, uint16_t x)
{
put_be16(b, htons(x));
}
static void
put_u32(struct ofpbuf *b, uint32_t x)
{
put_be32(b, htonl(x));
}
/* Converts 'learn' into a "struct nx_action_learn" and appends that action to
* 'ofpacts'. */
void
learn_to_nxast(const struct ofpact_learn *learn, struct ofpbuf *openflow)
{
const struct ofpact_learn_spec *spec;
struct nx_action_learn *nal;
size_t start_ofs;
start_ofs = openflow->size;
nal = ofputil_put_NXAST_LEARN(openflow);
nal->idle_timeout = htons(learn->idle_timeout);
nal->hard_timeout = htons(learn->hard_timeout);
nal->fin_idle_timeout = htons(learn->fin_idle_timeout);
nal->fin_hard_timeout = htons(learn->fin_hard_timeout);
nal->priority = htons(learn->priority);
nal->cookie = htonll(learn->cookie);
nal->flags = htons(learn->flags);
nal->table_id = learn->table_id;
for (spec = learn->specs; spec < &learn->specs[learn->n_specs]; spec++) {
put_u16(openflow, spec->n_bits | spec->dst_type | spec->src_type);
if (spec->src_type == NX_LEARN_SRC_FIELD) {
put_u32(openflow, spec->src.field->nxm_header);
put_u16(openflow, spec->src.ofs);
} else {
size_t n_dst_bytes = 2 * DIV_ROUND_UP(spec->n_bits, 16);
uint8_t *bits = ofpbuf_put_zeros(openflow, n_dst_bytes);
bitwise_copy(&spec->src_imm, sizeof spec->src_imm, 0,
bits, n_dst_bytes, 0,
spec->n_bits);
}
if (spec->dst_type == NX_LEARN_DST_MATCH ||
spec->dst_type == NX_LEARN_DST_LOAD) {
put_u32(openflow, spec->dst.field->nxm_header);
put_u16(openflow, spec->dst.ofs);
}
}
if ((openflow->size - start_ofs) % 8) {
ofpbuf_put_zeros(openflow, 8 - (openflow->size - start_ofs) % 8);
}
nal = ofpbuf_at_assert(openflow, start_ofs, sizeof *nal);
nal->len = htons(openflow->size - start_ofs);
}
/* 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 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;
cls_rule_init_catchall(&fm->cr, learn->priority);
fm->cookie = htonll(0);
fm->cookie_mask = htonll(0);
fm->new_cookie = htonll(learn->cookie);
fm->table_id = learn->table_id;
fm->command = OFPFC_MODIFY_STRICT;
fm->idle_timeout = learn->idle_timeout;
fm->hard_timeout = learn->hard_timeout;
fm->buffer_id = UINT32_MAX;
fm->out_port = OFPP_NONE;
fm->flags = learn->flags;
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;
}
for (spec = learn->specs; spec < &learn->specs[learn->n_specs]; spec++) {
union mf_subvalue value;
int chunk, ofs;
if (spec->src_type == NX_LEARN_SRC_FIELD) {
mf_read_subfield(&spec->src, flow, &value);
} else {
value = spec->src_imm;
}
switch (spec->dst_type) {
case NX_LEARN_DST_MATCH:
mf_write_subfield(&spec->dst, &value, &fm->cr);
break;
case NX_LEARN_DST_LOAD:
for (ofs = 0; ofs < spec->n_bits; ofs += chunk) {
struct ofpact_reg_load *load;
ovs_be64 value_be;
chunk = MIN(spec->n_bits - ofs, 64);
load = ofpact_put_REG_LOAD(ofpacts);
load->dst.field = spec->dst.field;
load->dst.ofs = spec->dst.ofs + ofs;
load->dst.n_bits = chunk;
memset(&value_be, 0, sizeof value_be);
bitwise_copy(&value, sizeof value, ofs,
&value_be, sizeof value_be, 0,
chunk);
load->value = ntohll(value_be);
}
break;
case NX_LEARN_DST_OUTPUT:
if (spec->n_bits <= 16
|| is_all_zeros(value.u8, sizeof value - 2)) {
uint16_t port = ntohs(value.be16[7]);
if (port < OFPP_MAX
|| port == OFPP_IN_PORT
|| port == OFPP_FLOOD
|| port == OFPP_LOCAL
|| port == OFPP_ALL) {
ofpact_put_OUTPUT(ofpacts)->port = port;
}
}
break;
}
}
ofpact_pad(ofpacts);
fm->ofpacts = ofpacts->data;
fm->ofpacts_len = ofpacts->size;
}
static void
learn_parse_load_immediate(const char *s, struct ofpact_learn_spec *spec)
{
const char *full_s = s;
const char *arrow = strstr(s, "->");
struct mf_subfield dst;
union mf_subvalue imm;
memset(&imm, 0, sizeof imm);
if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X') && arrow) {
const char *in = arrow - 1;
uint8_t *out = imm.u8 + sizeof imm.u8 - 1;
int n = arrow - (s + 2);
int i;
for (i = 0; i < n; i++) {
int hexit = hexit_value(in[-i]);
if (hexit < 0) {
ovs_fatal(0, "%s: bad hex digit in value", full_s);
}
out[-(i / 2)] |= i % 2 ? hexit << 4 : hexit;
}
s = arrow;
} else {
imm.be64[1] = htonll(strtoull(s, (char **) &s, 0));
}
if (strncmp(s, "->", 2)) {
ovs_fatal(0, "%s: missing `->' following value", full_s);
}
s += 2;
s = mf_parse_subfield(&dst, s);
if (*s != '\0') {
ovs_fatal(0, "%s: trailing garbage following destination", full_s);
}
if (!bitwise_is_all_zeros(&imm, sizeof imm, dst.n_bits,
(8 * sizeof imm) - dst.n_bits)) {
ovs_fatal(0, "%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->src_imm = imm;
spec->dst_type = NX_LEARN_DST_LOAD;
spec->dst = dst;
}
static void
learn_parse_spec(const char *orig, char *name, char *value,
struct ofpact_learn_spec *spec)
{
if (mf_from_name(name)) {
const struct mf_field *dst = mf_from_name(name);
union mf_value imm;
char *error;
error = mf_parse_value(dst, value, &imm);
if (error) {
ovs_fatal(0, "%s", error);
}
spec->n_bits = dst->n_bits;
spec->src_type = NX_LEARN_SRC_IMMEDIATE;
memset(&spec->src_imm, 0, sizeof spec->src_imm);
memcpy(&spec->src_imm.u8[sizeof spec->src_imm - dst->n_bytes],
&imm, dst->n_bytes);
spec->dst_type = NX_LEARN_DST_MATCH;
spec->dst.field = dst;
spec->dst.ofs = 0;
spec->dst.n_bits = dst->n_bits;
} else if (strchr(name, '[')) {
/* Parse destination and check prerequisites. */
if (mf_parse_subfield(&spec->dst, name)[0] != '\0') {
ovs_fatal(0, "%s: syntax error after NXM field name `%s'",
orig, name);
}
/* Parse source and check prerequisites. */
if (value[0] != '\0') {
if (mf_parse_subfield(&spec->src, value)[0] != '\0') {
ovs_fatal(0, "%s: syntax error after NXM field name `%s'",
orig, value);
}
if (spec->src.n_bits != spec->dst.n_bits) {
ovs_fatal(0, "%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->n_bits = spec->src.n_bits;
spec->src_type = NX_LEARN_SRC_FIELD;
spec->dst_type = NX_LEARN_DST_MATCH;
} else if (!strcmp(name, "load")) {
if (value[strcspn(value, "[-")] == '-') {
learn_parse_load_immediate(value, spec);
} else {
struct ofpact_reg_move move;
nxm_parse_reg_move(&move, value);
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")) {
if (mf_parse_subfield(&spec->src, value)[0] != '\0') {
ovs_fatal(0, "%s: syntax error after NXM field name `%s'",
orig, name);
}
spec->n_bits = spec->src.n_bits;
spec->src_type = NX_LEARN_SRC_FIELD;
spec->dst_type = NX_LEARN_DST_OUTPUT;
} else {
ovs_fatal(0, "%s: unknown keyword %s", orig, name);
}
}
/* Parses 'arg' as a set of arguments to the "learn" action and appends a
* matching OFPACT_LEARN action to 'ofpacts'. ovs-ofctl(8) describes the
* format parsed.
*
* Prints an error on stderr and aborts the program if 'arg' syntax is invalid.
*
* If 'flow' is nonnull, then it should be the flow from a cls_rule that is
* the matching rule for the learning action. This helps to better validate
* the action's arguments.
*
* Modifies 'arg'. */
void
learn_parse(char *arg, const struct flow *flow, struct ofpbuf *ofpacts)
{
char *orig = xstrdup(arg);
char *name, *value;
struct ofpact_learn *learn;
struct cls_rule rule;
enum ofperr error;
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;
cls_rule_init_catchall(&rule, 0);
while (ofputil_parse_key_value(&arg, &name, &value)) {
if (!strcmp(name, "table")) {
learn->table_id = atoi(value);
if (learn->table_id == 255) {
ovs_fatal(0, "%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 = strtoull(value, NULL, 0);
} else {
struct ofpact_learn_spec *spec;
spec = ofpbuf_put_zeros(ofpacts, sizeof *spec);
learn = ofpacts->l2;
learn->n_specs++;
learn_parse_spec(orig, name, value, spec);
/* Check prerequisites. */
if (spec->src_type == NX_LEARN_SRC_FIELD
&& flow && !mf_are_prereqs_ok(spec->src.field, flow)) {
ovs_fatal(0, "%s: cannot specify source field %s because "
"prerequisites are not satisfied",
orig, spec->src.field->name);
}
if ((spec->dst_type == NX_LEARN_DST_MATCH
|| spec->dst_type == NX_LEARN_DST_LOAD)
&& !mf_are_prereqs_ok(spec->dst.field, &rule.flow)) {
ovs_fatal(0, "%s: cannot specify destination field %s because "
"prerequisites are not satisfied",
orig, spec->dst.field->name);
}
/* Update 'rule' to allow for satisfying destination
* prerequisites. */
if (spec->src_type == NX_LEARN_SRC_IMMEDIATE
&& spec->dst_type == NX_LEARN_DST_MATCH) {
mf_write_subfield(&spec->dst, &spec->src_imm, &rule);
}
}
}
ofpact_update_len(ofpacts, &learn->ofpact);
/* In theory the above should have caught any errors, but... */
if (flow) {
error = learn_check(learn, flow);
if (error) {
ovs_fatal(0, "%s: %s", orig, ofperr_to_string(error));
}
}
free(orig);
}
static void
format_subvalue(const union mf_subvalue *subvalue, struct ds *s)
{
int i;
for (i = 0; i < ARRAY_SIZE(subvalue->u8); i++) {
if (subvalue->u8[i]) {
ds_put_format(s, "0x%"PRIx8, subvalue->u8[i]);
for (i++; i < ARRAY_SIZE(subvalue->u8); i++) {
ds_put_format(s, "%02"PRIx8, subvalue->u8[i]);
}
return;
}
}
ds_put_char(s, '0');
}
/* Appends a description of 'learn' to 's', in the format that ovs-ofctl(8)
* describes. */
void
learn_format(const struct ofpact_learn *learn, struct ds *s)
{
const struct ofpact_learn_spec *spec;
struct cls_rule rule;
cls_rule_init_catchall(&rule, 0);
ds_put_format(s, "learn(table=%"PRIu8, learn->table_id);
if (learn->idle_timeout != OFP_FLOW_PERMANENT) {
ds_put_format(s, ",idle_timeout=%"PRIu16, learn->idle_timeout);
}
if (learn->hard_timeout != OFP_FLOW_PERMANENT) {
ds_put_format(s, ",hard_timeout=%"PRIu16, learn->hard_timeout);
}
if (learn->fin_idle_timeout) {
ds_put_format(s, ",fin_idle_timeout=%"PRIu16, learn->fin_idle_timeout);
}
if (learn->fin_hard_timeout) {
ds_put_format(s, ",fin_hard_timeout=%"PRIu16, learn->fin_hard_timeout);
}
if (learn->priority != OFP_DEFAULT_PRIORITY) {
ds_put_format(s, ",priority=%"PRIu16, learn->priority);
}
if (learn->flags & OFPFF_SEND_FLOW_REM) {
ds_put_cstr(s, ",OFPFF_SEND_FLOW_REM");
}
if (learn->cookie != 0) {
ds_put_format(s, ",cookie=%#"PRIx64, learn->cookie);
}
for (spec = learn->specs; spec < &learn->specs[learn->n_specs]; spec++) {
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);
bitwise_copy(&spec->src_imm, sizeof spec->src_imm, 0,
&value, spec->dst.field->n_bytes, 0,
spec->dst.field->n_bits);
ds_put_format(s, "%s=", spec->dst.field->name);
mf_format(spec->dst.field, &value, NULL, s);
} else {
mf_format_subfield(&spec->dst, s);
ds_put_char(s, '=');
format_subvalue(&spec->src_imm, s);
}
break;
case NX_LEARN_SRC_FIELD | NX_LEARN_DST_MATCH:
mf_format_subfield(&spec->dst, s);
if (spec->src.field != spec->dst.field ||
spec->src.ofs != spec->dst.ofs) {
ds_put_char(s, '=');
mf_format_subfield(&spec->src, s);
}
break;
case NX_LEARN_SRC_IMMEDIATE | NX_LEARN_DST_LOAD:
ds_put_format(s, "load:");
format_subvalue(&spec->src_imm, s);
ds_put_cstr(s, "->");
mf_format_subfield(&spec->dst, s);
break;
case NX_LEARN_SRC_FIELD | NX_LEARN_DST_LOAD:
ds_put_cstr(s, "load:");
mf_format_subfield(&spec->src, s);
ds_put_cstr(s, "->");
mf_format_subfield(&spec->dst, s);
break;
case NX_LEARN_SRC_FIELD | NX_LEARN_DST_OUTPUT:
ds_put_cstr(s, "output:");
mf_format_subfield(&spec->src, s);
break;
}
}
ds_put_char(s, ')');
}
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