/*
* (C) 2021-2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* All Rights Reserved.
*
* Author: Neels Janosch Hofmeyr <nhofmeyr@sysmocom.de>
*
* SPDX-License-Identifier: GPL-2.0+
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <errno.h>
#include <osmocom/core/bits.h>
#include <osmocom/core/msgb.h>
#include <osmocom/gtlv/gtlv.h>
int osmo_gtlv_tag_inst_cmp(const struct osmo_gtlv_tag_inst *a, const struct osmo_gtlv_tag_inst *b)
{
int cmp;
if (a == b)
return 0;
if (!a)
return -1;
if (!b)
return 1;
cmp = OSMO_CMP(a->tag, b->tag);
if (cmp)
return cmp;
cmp = OSMO_CMP(a->instance_present ? 1 : 0, b->instance_present ? 1 : 0);
if (cmp)
return cmp;
if (a->instance_present)
return OSMO_CMP(a->instance, b->instance);
return 0;
}
int osmo_gtlv_tag_inst_to_str_buf(char *buf, size_t buflen, const struct osmo_gtlv_tag_inst *ti,
const struct value_string *tag_names)
{
struct osmo_strbuf sb = { .buf = buf, .len = buflen };
if (!tag_names)
OSMO_STRBUF_PRINTF(sb, "%u", ti->tag);
else
OSMO_STRBUF_PRINTF(sb, "%s", get_value_string(tag_names, ti->tag));
if (ti->instance_present)
OSMO_STRBUF_PRINTF(sb, "[%u]", ti->instance);
return sb.chars_needed;
}
char *osmo_gtlv_tag_inst_to_str_c(void *ctx, const struct osmo_gtlv_tag_inst *ti,
const struct value_string *tag_names)
{
OSMO_NAME_C_IMPL(ctx, 64, "ERROR", osmo_gtlv_tag_inst_to_str_buf, ti, tag_names)
}
static int next_tl_valid(const struct osmo_gtlv_load *gtlv, const uint8_t **ie_start_p, size_t *buflen_left_p)
{
const uint8_t *ie_start;
size_t buflen_left;
/* Start of next IE, or first IE for first invocation. */
if (!gtlv->val)
ie_start = gtlv->src.data;
else
ie_start = gtlv->val + gtlv->len;
/* Sanity */
if (ie_start < gtlv->src.data || ie_start > gtlv->src.data + gtlv->src.len)
return -ENOSPC;
buflen_left = gtlv->src.len - (ie_start - gtlv->src.data);
/* Too short for parsing an IE? Check also against integer overflow. */
if (buflen_left && ((buflen_left < gtlv->cfg->tl_min_size) || (buflen_left > gtlv->src.len)))
return -EBADMSG;
*ie_start_p = ie_start;
*buflen_left_p = buflen_left;
return 0;
}
/* Return a TLV IE from a message buffer.
*
* Return the first or next TLV data found in the data buffer, based on the state of the gtlv parameter.
* When gtlv->val is NULL, return the first IE in the data buffer.
* Otherwise assume that gtlv points at a valid IE in the data structure, and return the subsequent IE.
*
* Usage example:
*
* struct osmo_gtlv gtlv = {
* .cfg = osmo_t16l16v_cfg,
* .src = { .data = msgb_l3(msg), .len = msgb_l3len(msg) },
* };
* for (;;) {
* if (osmo_gtlv_next(>lv)) {
* printf("Error\n");
* break;
* }
* if (!gtlv.val) {
* printf("End\n");
* break;
* }
* printf("Tag %u: %zu octets: %s\n", gtlv.tag, gtlv.len, osmo_hexdump(gtlv.val, gtlv.len));
* }
*
* \param[inout] gtlv Buffer to return the IE data, and state for TLV parsing position. gtlv->msg should indicate the
* overall message buffer. The other gtlv members should be zero initialized before the first call, and
* remain unchanged between invocations of this function.
* \returns 0 on success, negative on TLV parsing error. The IE data is returned in gtlv->tag, gtlv->len and gtlv->val;
* gtlv->val == NULL if no more IEs remain in the buffer.
*/
int osmo_gtlv_load_next(struct osmo_gtlv_load *gtlv)
{
const uint8_t *ie_start;
const uint8_t *ie_end;
size_t buflen_left;
int rc;
rc = next_tl_valid(gtlv, &ie_start, &buflen_left);
if (rc)
return rc;
/* No more IEs? */
if (!buflen_left) {
gtlv->val = NULL;
return 0;
}
/* Locate next IE */
OSMO_ASSERT(gtlv->cfg->load_tl);
gtlv->ti = (struct osmo_gtlv_tag_inst){};
rc = gtlv->cfg->load_tl(gtlv, ie_start, buflen_left);
if (rc)
return rc;
/* Sanity */
ie_end = gtlv->val + gtlv->len;
if (ie_end < gtlv->src.data || ie_end > gtlv->src.data + gtlv->src.len)
return -EBADMSG;
return 0;
}
/* Return the tag of the IE that osmo_gtlv_next() would yield, do not change the gtlv state.
*
* \param[in] gtlv state for TLV parsing position; is not modified.
* \param[out] tag the tag number on success, if NULL don't return the tag.
* \param[out] instance the instance number or OSMO_GTLV_NO_INSTANCE if there is no instance value,
* if NULL don't return the instance value.
* \returns 0 on success, negative on TLV parsing error, -ENOENT when no more tags follow.
*/
int osmo_gtlv_load_peek_tag(const struct osmo_gtlv_load *gtlv, struct osmo_gtlv_tag_inst *ti)
{
const uint8_t *ie_start;
size_t buflen_left;
int rc;
/* Guard against modification by load_tl(). */
struct osmo_gtlv_load mtlv = *gtlv;
mtlv.ti = (struct osmo_gtlv_tag_inst){};
rc = next_tl_valid(&mtlv, &ie_start, &buflen_left);
if (rc)
return rc;
if (!buflen_left)
return -ENOENT;
/* Return next IE tag*/
OSMO_ASSERT(mtlv.cfg->load_tl);
rc = gtlv->cfg->load_tl(&mtlv, ie_start, buflen_left);
if (rc)
return -EBADMSG;
if (ti)
*ti = mtlv.ti;
return 0;
}
/* Same as osmo_gtlv_load_next(), but skip any IEs until the given tag is reached. Change the gtlv state only when success
* is returned.
* \param[out] gtlv Return the next IE's TLV info.
* \param[in] tag Tag value to match.
* \param[in] instance Instance value to match; For IEs that have no instance value (no TLIV), pass
* OSMO_GTLV_NO_INSTANCE.
* \return 0 when the tag is found. Return -ENOENT when no such tag follows and keep the gtlv unchanged. */
int osmo_gtlv_load_next_by_tag(struct osmo_gtlv_load *gtlv, unsigned int tag)
{
struct osmo_gtlv_tag_inst ti = { .tag = tag };
return osmo_gtlv_load_next_by_tag_inst(gtlv, &ti);
}
int osmo_gtlv_load_next_by_tag_inst(struct osmo_gtlv_load *gtlv, const struct osmo_gtlv_tag_inst *ti)
{
struct osmo_gtlv_load work = *gtlv;
for (;;) {
int rc = osmo_gtlv_load_next(&work);
if (rc)
return rc;
if (!work.val)
return -ENOENT;
if (!osmo_gtlv_tag_inst_cmp(&work.ti, ti)) {
*gtlv = work;
return 0;
}
}
}
/* Put tag header and length at the end of the msgb, according to gtlv->cfg->store_tl().
* If the length is not known yet, it can be passed as 0 at first, and osmo_gtlv_put_update_tl() can determine the
* resulting length after the value part was put into the msgb.
*
* Usage example:
*
* struct msgb *msg = msgb_alloc(1024, "foo"),
* struct osmo_gtlv_put gtlv = {
* .cfg = osmo_t16l16v_cfg,
* .dst = msg,
* }
*
* osmo_gtlv_put_tl(gtlv, 23, 0); // tag 23, length 0 = not known yet
*
* msgb_put(msg, 42);
* ...
* msgb_put(msg, 42);
* ...
* msgb_put(msg, 42);
*
* osmo_gtlv_put_update_tl(gtlv);
*
* Return 0 on success, -EINVAL if the tag value is invalid, -EMSGSIZE if len is too large.
*/
int osmo_gtlv_put_tl(struct osmo_gtlv_put *gtlv, unsigned int tag, size_t len)
{
struct osmo_gtlv_tag_inst ti = { .tag = tag };
return osmo_gtlv_put_tli(gtlv, &ti, len);
}
/* Put tag header, instance value and length at the end of the msgb, according to gtlv->cfg->store_tl().
* This is the same as osmo_gtlv_put_tl(), only osmo_gtlv_put_tl() passes instance = 0.
*/
int osmo_gtlv_put_tli(struct osmo_gtlv_put *gtlv, const struct osmo_gtlv_tag_inst *ti, size_t len)
{
int rc;
uint8_t *last_tl;
OSMO_ASSERT(gtlv->cfg->store_tl);
last_tl = gtlv->dst->tail;
rc = gtlv->cfg->store_tl(gtlv->dst->tail, msgb_tailroom(gtlv->dst), ti, len, gtlv);
if (rc < 0)
return rc;
if (rc > 0)
msgb_put(gtlv->dst, rc);
gtlv->last_ti = *ti;
gtlv->last_tl = last_tl;
gtlv->last_val = gtlv->dst->tail;
return 0;
}
/* Update the length of the last put IE header (last call to osmo_gtlv_put_tl()) to match with the current
* gtlv->dst->tail.
* Return 0 on success, -EMSGSIZE if the amount of data written since osmo_gtlv_put_tl() is too large.
*/
int osmo_gtlv_put_update_tl(struct osmo_gtlv_put *gtlv)
{
size_t len = gtlv->dst->tail - gtlv->last_val;
int rc = gtlv->cfg->store_tl(gtlv->last_tl, gtlv->last_val - gtlv->last_tl, >lv->last_ti, len, gtlv);
if (rc < 0)
return rc;
/* In case the TL has changed in size, hopefully the implementation has moved the msgb data. Make sure last_val
* points at the right place now. */
gtlv->last_val = gtlv->last_tl + rc;
return 0;
}
static int t8l8v_load_tl(struct osmo_gtlv_load *gtlv, const uint8_t *src_data, size_t src_data_len)
{
/* already validated in next_tl_valid(): src_data_len >= cfg->tl_min_size == 2. */
gtlv->ti.tag = src_data[0];
gtlv->len = src_data[1];
gtlv->val = src_data + 2;
return 0;
}
static int t8l8v_store_tl(uint8_t *dst_data, size_t dst_data_avail, const struct osmo_gtlv_tag_inst *ti, size_t len,
struct osmo_gtlv_put *gtlv)
{
if (ti->tag > UINT8_MAX)
return -EINVAL;
if (len > UINT8_MAX)
return -EMSGSIZE;
if (dst_data_avail < 2)
return -ENOSPC;
dst_data[0] = ti->tag;
dst_data[1] = len;
return 2;
}
const struct osmo_gtlv_cfg osmo_t8l8v_cfg = {
.tl_min_size = 2,
.load_tl = t8l8v_load_tl,
.store_tl = t8l8v_store_tl,
};
static int t16l16v_load_tl(struct osmo_gtlv_load *gtlv, const uint8_t *src_data, size_t src_data_len)
{
/* already validated in next_tl_valid(): src_data_len >= cfg->tl_min_size == 4. */
gtlv->ti.tag = osmo_load16be(src_data);
gtlv->len = osmo_load16be(src_data + 2);
gtlv->val = src_data + 4;
return 0;
}
static int t16l16v_store_tl(uint8_t *dst_data, size_t dst_data_avail, const struct osmo_gtlv_tag_inst *ti, size_t len,
struct osmo_gtlv_put *gtlv)
{
if (ti->tag > UINT16_MAX)
return -EINVAL;
if (len > UINT16_MAX)
return -EMSGSIZE;
if (dst_data_avail < 4)
return -ENOSPC;
osmo_store16be(ti->tag, dst_data);
osmo_store16be(len, dst_data + 2);
return 4;
}
const struct osmo_gtlv_cfg osmo_t16l16v_cfg = {
.tl_min_size = 4,
.load_tl = t16l16v_load_tl,
.store_tl = t16l16v_store_tl,
};