+ struct ofpact_reg_load *load = ofpact_put_REG_LOAD(ofpacts);
+ char *value;
+ char *delim;
+ char *key;
+ const struct mf_field *mf;
+ char *error;
+ union mf_value mf_value;
+
+ value = arg;
+ delim = strstr(arg, "->");
+ if (!delim) {
+ return xasprintf("%s: missing `->'", arg);
+ }
+ if (strlen(delim) <= strlen("->")) {
+ return xasprintf("%s: missing field name following `->'", arg);
+ }
+
+ key = delim + strlen("->");
+ mf = mf_from_name(key);
+ if (!mf) {
+ return xasprintf("%s is not a valid OXM field name", key);
+ }
+ if (!mf->writable) {
+ return xasprintf("%s is read-only", key);
+ }
+
+ delim[0] = '\0';
+ error = mf_parse_value(mf, value, &mf_value);
+ if (error) {
+ return error;
+ }
+ if (!mf_is_value_valid(mf, &mf_value)) {
+ return xasprintf("%s is not a valid value for field %s", value, key);
+ }
+ ofpact_set_field_init(load, mf, &mf_value);
+
+ *usable_protocols &= mf->usable_protocols;
+ return NULL;
+}
+
+/* Parses 'arg' as the argument to a "set_field" action, and appends such an
+ * action to 'ofpacts'.
+ *
+ * Returns NULL if successful, otherwise a malloc()'d string describing the
+ * error. The caller is responsible for freeing the returned string. */
+static char * WARN_UNUSED_RESULT
+set_field_parse(const char *arg, struct ofpbuf *ofpacts,
+ enum ofputil_protocol *usable_protocols)
+{
+ char *copy = xstrdup(arg);
+ char *error = set_field_parse__(copy, ofpacts, usable_protocols);
+ free(copy);
+ return error;
+}
+
+/* Parses 'arg' as the argument to a "write_metadata" instruction, and appends
+ * such an action to 'ofpacts'.
+ *
+ * Returns NULL if successful, otherwise a malloc()'d string describing the
+ * error. The caller is responsible for freeing the returned string. */
+static char * WARN_UNUSED_RESULT
+parse_metadata(struct ofpbuf *b, char *arg)
+{
+ struct ofpact_metadata *om;
+ char *mask = strchr(arg, '/');
+
+ om = ofpact_put_WRITE_METADATA(b);
+
+ if (mask) {
+ char *error;
+
+ *mask = '\0';
+ error = str_to_be64(mask + 1, &om->mask);
+ if (error) {
+ return error;
+ }
+ } else {
+ om->mask = htonll(UINT64_MAX);
+ }
+
+ return str_to_be64(arg, &om->metadata);
+}
+
+/* Parses 'arg' as the argument to a "sample" action, and appends such an
+ * action to 'ofpacts'.
+ *
+ * Returns NULL if successful, otherwise a malloc()'d string describing the
+ * error. The caller is responsible for freeing the returned string. */
+static char * WARN_UNUSED_RESULT
+parse_sample(struct ofpbuf *b, char *arg)
+{
+ struct ofpact_sample *os = ofpact_put_SAMPLE(b);
+ char *key, *value;
+
+ while (ofputil_parse_key_value(&arg, &key, &value)) {
+ char *error = NULL;
+
+ if (!strcmp(key, "probability")) {
+ error = str_to_u16(value, "probability", &os->probability);
+ if (!error && os->probability == 0) {
+ error = xasprintf("invalid probability value \"%s\"", value);
+ }
+ } else if (!strcmp(key, "collector_set_id")) {
+ error = str_to_u32(value, &os->collector_set_id);
+ } else if (!strcmp(key, "obs_domain_id")) {
+ error = str_to_u32(value, &os->obs_domain_id);
+ } else if (!strcmp(key, "obs_point_id")) {
+ error = str_to_u32(value, &os->obs_point_id);
+ } else {
+ error = xasprintf("invalid key \"%s\" in \"sample\" argument",
+ key);
+ }
+ if (error) {
+ return error;
+ }
+ }
+ if (os->probability == 0) {
+ return xstrdup("non-zero \"probability\" must be specified on sample");
+ }
+ return NULL;
+}
+
+/* Parses 'arg' as the argument to action 'code', and appends such an action to
+ * 'ofpacts'.
+ *
+ * Returns NULL if successful, otherwise a malloc()'d string describing the
+ * error. The caller is responsible for freeing the returned string. */
+static char * WARN_UNUSED_RESULT
+parse_named_action(enum ofputil_action_code code,
+ char *arg, struct ofpbuf *ofpacts,
+ enum ofputil_protocol *usable_protocols)
+{
+ size_t orig_size = ofpacts->size;
+ struct ofpact_tunnel *tunnel;
+ char *error = NULL;
+ uint16_t ethertype = 0;
+ uint16_t vid = 0;
+ uint8_t tos = 0;
+ uint8_t pcp = 0;