+/*
+ * Copyright (c) 2011 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.
+ */
+
+#include <config.h>
+
+#include "learn.h"
+
+#include "byte-order.h"
+#include "dynamic-string.h"
+#include "meta-flow.h"
+#include "nx-match.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 uint64_t
+get_bits(int n_bits, const void **p)
+{
+ int n_segs = DIV_ROUND_UP(n_bits, 16);
+ uint64_t value;
+
+ value = 0;
+ while (n_segs-- > 0) {
+ value = (value << 16) | ntohs(get_be16(p));
+ }
+ return value;
+}
+
+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;
+}
+
+static int
+learn_check_header(uint16_t header, size_t len)
+{
+ int src_type = header & NX_LEARN_SRC_MASK;
+ int dst_type = header & NX_LEARN_DST_MASK;
+
+ /* Check for valid src and dst type combination. */
+ if (dst_type == NX_LEARN_DST_MATCH ||
+ dst_type == NX_LEARN_DST_LOAD ||
+ (dst_type == NX_LEARN_DST_OUTPUT &&
+ src_type == NX_LEARN_SRC_FIELD)) {
+ /* OK. */
+ } else {
+ return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_ARGUMENT);
+ }
+
+ /* Check that the arguments don't overrun the end of the action. */
+ if (len < learn_min_len(header)) {
+ return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_LEN);
+ }
+
+ return 0;
+}
+
+/* Checks that 'learn' (which must be at least 'sizeof *learn' bytes long) is a
+ * valid action on 'flow'. */
+int
+learn_check(const struct nx_action_learn *learn, const struct flow *flow)
+{
+ struct cls_rule rule;
+ const void *p, *end;
+
+ cls_rule_init_catchall(&rule, 0);
+
+ if (learn->flags & ~htons(OFPFF_SEND_FLOW_REM)
+ || !is_all_zeros(learn->pad, sizeof learn->pad)
+ || learn->table_id == 0xff) {
+ return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_ARGUMENT);
+ }
+
+ end = (char *) learn + ntohs(learn->len);
+ for (p = learn + 1; p != end; ) {
+ uint16_t header = ntohs(get_be16(&p));
+ 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;
+
+ uint64_t value;
+ int error;
+
+ if (!header) {
+ break;
+ }
+
+ error = learn_check_header(header, (char *) end - (char *) p);
+ if (error) {
+ return error;
+ }
+
+ /* Check the source. */
+ if (src_type == NX_LEARN_SRC_FIELD) {
+ ovs_be32 src_field = get_be32(&p);
+ int src_ofs = ntohs(get_be16(&p));
+
+ error = nxm_src_check(src_field, src_ofs, n_bits, flow);
+ if (error) {
+ return error;
+ }
+ value = 0;
+ } else {
+ value = get_bits(n_bits, &p);
+ }
+
+ /* Check the destination. */
+ if (dst_type == NX_LEARN_DST_MATCH || dst_type == NX_LEARN_DST_LOAD) {
+ ovs_be32 dst_field = get_be32(&p);
+ int dst_ofs = ntohs(get_be16(&p));
+ int error;
+
+ error = nxm_dst_check(dst_field, dst_ofs, n_bits, &rule.flow);
+ if (error) {
+ return error;
+ }
+
+ if (dst_type == NX_LEARN_DST_MATCH
+ && src_type == NX_LEARN_SRC_IMMEDIATE) {
+ mf_set_subfield(nxm_field_to_mf_field(ntohl(dst_field)), value,
+ dst_ofs, n_bits, &rule);
+ }
+ }
+ }
+ if (!is_all_zeros(p, (char *) end - (char *) p)) {
+ return ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_ARGUMENT);
+ }
+
+ return 0;
+}
+
+void
+learn_execute(const struct nx_action_learn *learn, const struct flow *flow,
+ struct ofputil_flow_mod *fm)
+{
+ const void *p, *end;
+ struct ofpbuf actions;
+
+ cls_rule_init_catchall(&fm->cr, ntohs(learn->priority));
+ fm->cookie = learn->cookie;
+ fm->table_id = learn->table_id;
+ fm->command = OFPFC_MODIFY_STRICT;
+ fm->idle_timeout = ntohs(learn->idle_timeout);
+ fm->hard_timeout = ntohs(learn->hard_timeout);
+ fm->buffer_id = UINT32_MAX;
+ fm->out_port = OFPP_NONE;
+ fm->flags = ntohs(learn->flags) & OFPFF_SEND_FLOW_REM;
+ fm->actions = NULL;
+ fm->n_actions = 0;
+
+ ofpbuf_init(&actions, 64);
+
+ for (p = learn + 1, end = (char *) learn + ntohs(learn->len); p != end; ) {
+ uint16_t header = ntohs(get_be16(&p));
+ 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;
+ uint64_t value;
+
+ struct nx_action_reg_load *load;
+ ovs_be32 dst_field;
+ int dst_ofs;
+
+ if (!header) {
+ break;
+ }
+
+ if (src_type == NX_LEARN_SRC_FIELD) {
+ ovs_be32 src_field = get_be32(&p);
+ int src_ofs = ntohs(get_be16(&p));
+
+ value = nxm_read_field_bits(src_field,
+ nxm_encode_ofs_nbits(src_ofs, n_bits),
+ flow);
+ } else {
+ value = get_bits(n_bits, &p);
+ }
+
+ switch (dst_type) {
+ case NX_LEARN_DST_MATCH:
+ dst_field = get_be32(&p);
+ dst_ofs = ntohs(get_be16(&p));
+ mf_set_subfield(nxm_field_to_mf_field(ntohl(dst_field)), value,
+ dst_ofs, n_bits, &fm->cr);
+ break;
+
+ case NX_LEARN_DST_LOAD:
+ dst_field = get_be32(&p);
+ dst_ofs = ntohs(get_be16(&p));
+ load = ofputil_put_NXAST_REG_LOAD(&actions);
+ load->ofs_nbits = nxm_encode_ofs_nbits(dst_ofs, n_bits);
+ load->dst = dst_field;
+ load->value = htonll(value);
+ break;
+
+ case NX_LEARN_DST_OUTPUT:
+ ofputil_put_OFPAT_OUTPUT(&actions)->port = htons(value);
+ break;
+ }
+ }
+
+ fm->actions = ofpbuf_steal_data(&actions);
+ fm->n_actions = actions.size / sizeof(struct ofp_action_header);
+}
+
+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));
+}
+
+struct learn_spec {
+ int n_bits;
+
+ int src_type;
+ const struct mf_field *src;
+ int src_ofs;
+ uint8_t src_imm[sizeof(union mf_value)];
+
+ int dst_type;
+ const struct mf_field *dst;
+ int dst_ofs;
+};
+
+static void
+learn_parse_spec(const char *orig, char *name, char *value,
+ struct 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;
+ spec->src = NULL;
+ spec->src_ofs = 0;
+ memcpy(spec->src_imm, &imm, dst->n_bytes);
+ spec->dst_type = NX_LEARN_DST_MATCH;
+ spec->dst = dst;
+ spec->dst_ofs = 0;
+ } else if (strchr(name, '[')) {
+ uint32_t src_header, dst_header;
+ int src_ofs, dst_ofs;
+ int n_bits;
+
+ /* Parse destination and check prerequisites. */
+ if (nxm_parse_field_bits(name, &dst_header, &dst_ofs,
+ &n_bits)[0] != '\0') {
+ ovs_fatal(0, "%s: syntax error after NXM field name `%s'",
+ orig, name);
+ }
+
+ /* Parse source and check prerequisites. */
+ if (value[0] != '\0') {
+ int src_nbits;
+
+ if (nxm_parse_field_bits(value, &src_header, &src_ofs,
+ &src_nbits)[0] != '\0') {
+ ovs_fatal(0, "%s: syntax error after NXM field name `%s'",
+ orig, value);
+ }
+ if (src_nbits != n_bits) {
+ ovs_fatal(0, "%s: bit widths of %s (%d) and %s (%d) differ",
+ orig, name, dst_header, value, dst_header);
+ }
+ } else {
+ src_header = dst_header;
+ src_ofs = dst_ofs;
+ }
+
+ spec->n_bits = n_bits;
+ spec->src_type = NX_LEARN_SRC_FIELD;
+ spec->src = nxm_field_to_mf_field(src_header);
+ spec->src_ofs = src_ofs;
+ spec->dst_type = NX_LEARN_DST_MATCH;
+ spec->dst = nxm_field_to_mf_field(dst_header);
+ spec->dst_ofs = 0;
+ } else if (!strcmp(name, "load")) {
+ if (value[strcspn(value, "[-")] == '-') {
+ struct nx_action_reg_load load;
+ int nbits, imm_bytes;
+ uint64_t imm;
+ int i;
+
+ nxm_parse_reg_load(&load, value);
+ nbits = nxm_decode_n_bits(load.ofs_nbits);
+ imm_bytes = DIV_ROUND_UP(nbits, 8);
+ imm = ntohll(load.value);
+
+ spec->n_bits = nbits;
+ spec->src_type = NX_LEARN_SRC_IMMEDIATE;
+ spec->src = NULL;
+ spec->src_ofs = 0;
+ for (i = 0; i < imm_bytes; i++) {
+ spec->src_imm[i] = imm >> ((imm_bytes - i - 1) * 8);
+ }
+ spec->dst_type = NX_LEARN_DST_LOAD;
+ spec->dst = nxm_field_to_mf_field(ntohl(load.dst));
+ spec->dst_ofs = nxm_decode_ofs(load.ofs_nbits);
+ } else {
+ struct nx_action_reg_move move;
+
+ nxm_parse_reg_move(&move, value);
+
+ spec->n_bits = ntohs(move.n_bits);
+ spec->src_type = NX_LEARN_SRC_FIELD;
+ spec->src = nxm_field_to_mf_field(ntohl(move.src));
+ spec->src_ofs = ntohs(move.src_ofs);
+ spec->dst_type = NX_LEARN_DST_LOAD;
+ spec->dst = nxm_field_to_mf_field(ntohl(move.dst));
+ spec->dst_ofs = ntohs(move.dst_ofs);
+ }
+ } else if (!strcmp(name, "output")) {
+ uint32_t header;
+ int ofs, n_bits;
+
+ if (nxm_parse_field_bits(value, &header, &ofs, &n_bits)[0] != '\0') {
+ ovs_fatal(0, "%s: syntax error after NXM field name `%s'",
+ orig, name);
+ }
+
+ spec->n_bits = n_bits;
+ spec->src_type = NX_LEARN_SRC_FIELD;
+ spec->src = nxm_field_to_mf_field(header);
+ spec->src_ofs = ofs;
+ spec->dst_type = NX_LEARN_DST_OUTPUT;
+ spec->dst = NULL;
+ spec->dst_ofs = 0;
+ } else {
+ ovs_fatal(0, "%s: unknown keyword %s", orig, name);
+ }
+}
+
+void
+learn_parse(struct ofpbuf *b, char *arg, const struct flow *flow)
+{
+ char *orig = xstrdup(arg);
+ char *name, *value;
+ size_t learn_ofs;
+ size_t len;
+
+ struct nx_action_learn *learn;
+ struct cls_rule rule;
+
+ learn_ofs = b->size;
+ learn = ofputil_put_NXAST_LEARN(b);
+ learn->idle_timeout = htons(OFP_FLOW_PERMANENT);
+ learn->hard_timeout = htons(OFP_FLOW_PERMANENT);
+ learn->priority = htons(OFP_DEFAULT_PRIORITY);
+ learn->cookie = htonll(0);
+ learn->flags = htons(0);
+ learn->table_id = 1;
+
+ cls_rule_init_catchall(&rule, 0);
+ while (ofputil_parse_key_value(&arg, &name, &value)) {
+ learn = ofpbuf_at_assert(b, learn_ofs, sizeof *learn);
+ 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 = htons(atoi(value));
+ } else if (!strcmp(name, "idle_timeout")) {
+ learn->idle_timeout = htons(atoi(value));
+ } else if (!strcmp(name, "hard_timeout")) {
+ learn->hard_timeout = htons(atoi(value));
+ } else if (!strcmp(name, "cookie")) {
+ learn->cookie = htonll(strtoull(value, NULL, 0));
+ } else {
+ struct learn_spec spec;
+
+ learn_parse_spec(orig, name, value, &spec);
+
+ /* Check prerequisites. */
+ if (spec.src_type == NX_LEARN_SRC_FIELD
+ && !mf_are_prereqs_ok(spec.src, flow)) {
+ ovs_fatal(0, "%s: cannot specify source field %s because "
+ "prerequisites are not satisfied",
+ orig, spec.src->name);
+ }
+ if ((spec.dst_type == NX_LEARN_DST_MATCH
+ || spec.dst_type == NX_LEARN_DST_LOAD)
+ && !mf_are_prereqs_ok(spec.dst, &rule.flow)) {
+ ovs_fatal(0, "%s: cannot specify destination field %s because "
+ "prerequisites are not satisfied",
+ orig, spec.dst->name);
+ }
+
+ /* Update 'rule' to allow for satisfying destination
+ * prerequisites. */
+ if (spec.src_type == NX_LEARN_SRC_IMMEDIATE
+ && spec.dst_type == NX_LEARN_DST_MATCH
+ && spec.dst_ofs == 0
+ && spec.n_bits == spec.dst->n_bytes * 8) {
+ union mf_value imm;
+
+ memcpy(&imm, spec.src_imm, spec.dst->n_bytes);
+ mf_set_value(spec.dst, &imm, &rule);
+ }
+
+ /* Output the flow_mod_spec. */
+ put_u16(b, spec.n_bits | spec.src_type | spec.dst_type);
+ if (spec.src_type == NX_LEARN_SRC_IMMEDIATE) {
+ int n_bytes = DIV_ROUND_UP(spec.n_bits, 8);
+ if (n_bytes % 2) {
+ ofpbuf_put_zeros(b, 1);
+ }
+ ofpbuf_put(b, spec.src_imm, n_bytes);
+ } else {
+ put_u32(b, spec.src->nxm_header);
+ put_u16(b, spec.src_ofs);
+ }
+ if (spec.dst_type == NX_LEARN_DST_MATCH ||
+ spec.dst_type == NX_LEARN_DST_LOAD) {
+ put_u32(b, spec.dst->nxm_header);
+ put_u16(b, spec.dst_ofs);
+ } else {
+ assert(spec.dst_type == NX_LEARN_DST_OUTPUT);
+ }
+ }
+ }
+ free(orig);
+
+ put_u16(b, 0);
+
+ len = b->size - learn_ofs;
+ if (len % 8) {
+ ofpbuf_put_zeros(b, 8 - len % 8);
+ }
+
+ learn = ofpbuf_at_assert(b, learn_ofs, sizeof *learn);
+ learn->len = htons(b->size - learn_ofs);
+}
+
+void
+learn_format(const struct nx_action_learn *learn, struct ds *s)
+{
+ struct cls_rule rule;
+ const void *p, *end;
+
+ cls_rule_init_catchall(&rule, 0);
+
+ ds_put_format(s, "learn(table=%"PRIu8, learn->table_id);
+ if (learn->idle_timeout != htons(OFP_FLOW_PERMANENT)) {
+ ds_put_format(s, ",idle_timeout=%"PRIu16, ntohs(learn->idle_timeout));
+ }
+ if (learn->hard_timeout != htons(OFP_FLOW_PERMANENT)) {
+ ds_put_format(s, ",hard_timeout=%"PRIu16, ntohs(learn->hard_timeout));
+ }
+ if (learn->priority != htons(OFP_DEFAULT_PRIORITY)) {
+ ds_put_format(s, ",priority=%"PRIu16, ntohs(learn->priority));
+ }
+ if (learn->flags & htons(OFPFF_SEND_FLOW_REM)) {
+ ds_put_cstr(s, ",OFPFF_SEND_FLOW_REM");
+ }
+ if (learn->flags & htons(~OFPFF_SEND_FLOW_REM)) {
+ ds_put_format(s, ",***flags=%"PRIu16"***",
+ ntohs(learn->flags) & ~OFPFF_SEND_FLOW_REM);
+ }
+ if (learn->cookie != htonll(0)) {
+ ds_put_format(s, ",cookie=0x%"PRIx64, ntohll(learn->cookie));
+ }
+ if (!is_all_zeros(learn->pad, sizeof learn->pad)) {
+ ds_put_cstr(s, ",***nonzero pad***");
+ }
+
+ end = (char *) learn + ntohs(learn->len);
+ for (p = learn + 1; p != end; ) {
+ uint16_t header = ntohs(get_be16(&p));
+ int n_bits = header & NX_LEARN_N_BITS_MASK;
+
+ int src_type = header & NX_LEARN_SRC_MASK;
+ uint32_t src_header;
+ int src_ofs;
+ const uint8_t *src_value;
+ int src_value_bytes;
+
+ int dst_type = header & NX_LEARN_DST_MASK;
+ uint32_t dst_header;
+ int dst_ofs;
+ const struct mf_field *dst_field;
+
+ int error;
+ int i;
+
+ if (!header) {
+ break;
+ }
+
+ error = learn_check_header(header, (char *) end - (char *) p);
+ if (error == ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_ARGUMENT)) {
+ ds_put_format(s, ",***bad flow_mod_spec header %"PRIx16"***)",
+ header);
+ return;
+ } else if (error == ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_LEN)) {
+ ds_put_format(s, ",***flow_mod_spec at offset %td is %u bytes "
+ "long but only %td bytes are left***)",
+ (char *) p - (char *) (learn + 1) - 2,
+ learn_min_len(header) + 2,
+ (char *) end - (char *) p + 2);
+ return;
+ }
+ assert(!error);
+
+ /* Get the source. */
+ if (src_type == NX_LEARN_SRC_FIELD) {
+ src_header = ntohl(get_be32(&p));
+ src_ofs = ntohs(get_be16(&p));
+ src_value_bytes = 0;
+ src_value = NULL;
+ } else {
+ src_header = 0;
+ src_ofs = 0;
+ src_value_bytes = 2 * DIV_ROUND_UP(n_bits, 16);
+ src_value = p;
+ p = (const void *) ((const uint8_t *) p + src_value_bytes);
+ }
+
+ /* Get the destination. */
+ if (dst_type == NX_LEARN_DST_MATCH || dst_type == NX_LEARN_DST_LOAD) {
+ dst_header = ntohl(get_be32(&p));
+ dst_field = nxm_field_to_mf_field(dst_header);
+ dst_ofs = ntohs(get_be16(&p));
+ } else {
+ dst_header = 0;
+ dst_field = NULL;
+ dst_ofs = 0;
+ }
+
+ ds_put_char(s, ',');
+
+ switch (src_type | dst_type) {
+ case NX_LEARN_SRC_IMMEDIATE | NX_LEARN_DST_MATCH:
+ if (dst_field && dst_ofs == 0 && n_bits == dst_field->n_bits) {
+ union mf_value value;
+ uint8_t *bytes = (uint8_t *) &value;
+
+ memset(&value, 0, sizeof value);
+ memcpy(&bytes[dst_field->n_bytes - src_value_bytes],
+ src_value, src_value_bytes);
+ ds_put_format(s, "%s=", dst_field->name);
+ mf_format(dst_field, &value, NULL, s);
+ } else {
+ nxm_format_field_bits(s, dst_header, dst_ofs, n_bits);
+ ds_put_cstr(s, "=0x");
+ for (i = 0; i < src_value_bytes; i++) {
+ ds_put_format(s, "%02"PRIx8, src_value[i]);
+ }
+ }
+ break;
+
+ case NX_LEARN_SRC_FIELD | NX_LEARN_DST_MATCH:
+ nxm_format_field_bits(s, dst_header, dst_ofs, n_bits);
+ if (src_header != dst_header || src_ofs != dst_ofs) {
+ ds_put_char(s, '=');
+ nxm_format_field_bits(s, src_header, src_ofs, n_bits);
+ }
+ break;
+
+ case NX_LEARN_SRC_IMMEDIATE | NX_LEARN_DST_LOAD:
+ ds_put_cstr(s, "load:0x");
+ for (i = 0; i < src_value_bytes; i++) {
+ ds_put_format(s, "%02"PRIx8, src_value[i]);
+ }
+ ds_put_cstr(s, "->");
+ nxm_format_field_bits(s, dst_header, dst_ofs, n_bits);
+ break;
+
+ case NX_LEARN_SRC_FIELD | NX_LEARN_DST_LOAD:
+ ds_put_cstr(s, "load:");
+ nxm_format_field_bits(s, src_header, src_ofs, n_bits);
+ ds_put_cstr(s, "->");
+ nxm_format_field_bits(s, dst_header, dst_ofs, n_bits);
+ break;
+
+ case NX_LEARN_SRC_FIELD | NX_LEARN_DST_OUTPUT:
+ ds_put_cstr(s, "output:");
+ nxm_format_field_bits(s, src_header, src_ofs, n_bits);
+ break;
+ }
+ }
+ if (!is_all_zeros(p, (char *) end - (char *) p)) {
+ ds_put_cstr(s, ",***nonzero trailer***");
+ }
+ ds_put_char(s, ')');
+}