[M] Change in osmo-mgw[master]: add fmtp.h

neels has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-mgw/+/35434?usp=email ) Change subject: add fmtp.h ...................................................................... add fmtp.h Upcoming patches will add handling of arbitrary ftmp strings to osmo-mgw as well as libosmo-mgcp-client (If58590bda8627519ff07e0b6f43aa47a274f052b). Add generic API for handling ftmp strings. The primary intended user is osmo-mgw, but this is also generally useful to libosmo-mgcp-client callers for parsing the received fmtp. We discussed that fmtp.[hc] should be published in libosmo-mgcp-client, but also built within osmo-mgw. Hence: - put fmtp.h and .c in libosmo-mgcp-client/ - in osmo-mgw code, use #include <mgcp_client/fmtp.h> and build the src/libosmo-mgcp-client/fmtp.c also into libosmo-mgcp.a. (This is currently the quickest solution and without side effects since fmtp.c is fully self-contained; an alternative would be adding a not-installed libmgcp-common.a within the build tree) Change-Id: I3eaea353dbd98c19212199b564342d0ac16cbc07 --- M include/Makefile.am A include/osmocom/mgcp_client/fmtp.h M src/libosmo-mgcp-client/Makefile.am A src/libosmo-mgcp-client/fmtp.c M src/libosmo-mgcp/Makefile.am 5 files changed, 179 insertions(+), 0 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-mgw refs/changes/34/35434/1 diff --git a/include/Makefile.am b/include/Makefile.am index c72cba8..031e7e6 100644 --- a/include/Makefile.am +++ b/include/Makefile.am @@ -8,6 +8,7 @@ osmocom/mgcp_client/mgcp_client_endpoint_fsm.h \ osmocom/mgcp_client/mgcp_client_fsm.h \ osmocom/mgcp_client/mgcp_client_pool.h \ + osmocom/mgcp_client/fmtp.h \ $(NULL) noinst_HEADERS = \ diff --git a/include/osmocom/mgcp_client/fmtp.h b/include/osmocom/mgcp_client/fmtp.h new file mode 100644 index 0000000..863fc01 --- /dev/null +++ b/include/osmocom/mgcp_client/fmtp.h @@ -0,0 +1,29 @@ +#pragma once + +#include <stddef.h> +#include <stdbool.h> + +#define OSMO_SDP_NAME_A "a" +#define OSMO_SDP_NAME_FMTP "fmtp" +#define OSMO_SDP_NAME_AMR_OCTET_ALIGN "octet-align" + +#define OSMO_SDP_VAL_AMR_OCTET_ALIGN_0 OSMO_SDP_NAME_AMR_OCTET_ALIGN "=0" +#define OSMO_SDP_VAL_AMR_OCTET_ALIGN_1 OSMO_SDP_NAME_AMR_OCTET_ALIGN "=1" + +/* "fmtp:" */ +#define OSMO_SDP_PREFIX_FMTP OSMO_SDP_NAME_FMTP ":" +/* "a=fmtp:" */ +#define OSMO_SDP_PREFIX_A_FMTP OSMO_SDP_NAME_A "=" OSMO_SDP_PREFIX_FMTP + +bool osmo_sdp_fmtp_get_val(char *val, size_t val_size, const char *fmtp, const char *option_name); +int osmo_sdp_fmtp_get_int(const char *fmtp, const char *option_name, int default_value); + +/* Some AMR related fmtp parameters as in https://www.rfc-editor.org/rfc/rfc4867#section-8.1 that osmo-mgw needs.*/ +bool osmo_sdp_fmtp_amr_is_octet_aligned(const char *fmtp); + +/*! To compose AMR related fmtp indicating octet-align. + * Usage: + * printf("%s", OSMO_SDP_AMR_SET_OCTET_ALIGN(oa_flag)); + */ +#define OSMO_SDP_AMR_SET_OCTET_ALIGN(VAL) \ + ((VAL) ? OSMO_SDP_VAL_AMR_OCTET_ALIGN_1 : OSMO_SDP_VAL_AMR_OCTET_ALIGN_0 ) diff --git a/src/libosmo-mgcp-client/Makefile.am b/src/libosmo-mgcp-client/Makefile.am index b2bed9a..e120289 100644 --- a/src/libosmo-mgcp-client/Makefile.am +++ b/src/libosmo-mgcp-client/Makefile.am @@ -31,6 +31,7 @@ mgcp_client_fsm.c \ mgcp_client_endpoint_fsm.c \ mgcp_client_pool.c \ + fmtp.c \ $(NULL) libosmo_mgcp_client_la_LDFLAGS = \ diff --git a/src/libosmo-mgcp-client/fmtp.c b/src/libosmo-mgcp-client/fmtp.c new file mode 100644 index 0000000..b7a8bd9 --- /dev/null +++ b/src/libosmo-mgcp-client/fmtp.c @@ -0,0 +1,120 @@ +/* + * (C) 2023-2015 by sysmocom - s.f.m.c. GmbH &lt;info(a)sysmocom.de&gt; + * All Rights Reserved + * + * Author: Neels Hofmeyr + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation; either version 3 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 Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ +#include <string.h> +#include <ctype.h> +#include <osmocom/core/utils.h> +#include <osmocom/core/logging.h> +#include <osmocom/mgcp_client/fmtp.h> + +static const char *fmtp_next_option(const char *fmtp) +{ + for (; fmtp && *fmtp && *fmtp != ';'; fmtp++); + for (; fmtp && isspace(*fmtp); fmtp++); + return fmtp; +} + +/*! Parse a given SDP fmtp value string, returning the value of a specific option, if present. + * + * Example: + * + * const char *fmtp_vals = "octet-align=1;mode-set=0,2,4,7"; + * + * char res[23]; + * if (osmo_sdp_fmtp_get_val(res, sizeof(res), fmtp_vals, "mode-set")) + * use_modeset(res); + * else + * use_modeset(MY_DEFAULT_MODESET); + * + * \param[out] val Buffer to write the option's value to. + * \param[in] val_size Space available in val. + * \param[in] fmtp fmtp value string to parse -- must not contain the "a=fmtp:N " prefix, only the value part. + * \param[in] option_name Which fmtp option to get the value for. + * \return true when the option was found, false when it was not present. + */ +bool osmo_sdp_fmtp_get_val(char *val, size_t val_size, const char *fmtp, const char *option_name) +{ + const char *pos = fmtp; + const char *end; + int option_name_len = strlen(option_name); + for (; pos && *pos; pos = fmtp_next_option(pos)) { + if (!osmo_str_startswith(pos, option_name)) + continue; + pos += option_name_len; + if (*pos != '=') + continue; + pos++; + break; + } + + if (!pos || !*pos) + return false; + + end = fmtp_next_option(pos); + OSMO_ASSERT(end); + if (val && val_size) + osmo_strlcpy(val, pos, OSMO_MIN(val_size, end - pos + 1)); + return true; +} + +/*! Parse a given SDP fmtp value string, returning the value of a specific integer option, if present. + * + * Example: + * + * const char *fmtp_vals = "octet-align=1;mode-set=0,2,4,7"; + * bool oa = osmo_sdp_fmtp_get_int(fmtp_vals, OSMO_SDP_AMR_OCTET_ALIGN_NAME, 1); + * + * \param[in] fmtp fmtp value string to parse -- must not contain the "a=fmtp:N " prefix, only the value part. + * \param[in] option_name Which fmtp option to get the value for. + * \param[in] default_value If option_name is not present or cannot be parsed as integer, return this instead. + * \return the integer value when the option was found and actually an integer, default_value otherwise. + */ +int osmo_sdp_fmtp_get_int(const char *fmtp, const char *option_name, int default_value) +{ + char val[128]; + if (!osmo_sdp_fmtp_get_val(val, sizeof(val), fmtp, option_name)) + return default_value; + if (!val[0]) + return default_value; + int i; + if (osmo_str_to_int(&i, val, 10, 0, 1)) { + /* error parsing number */ + LOGP(DLMGCP, LOGL_ERROR, "Invalid number in fmtp parameter '%s': '%s'\n", option_name, val); + return default_value; + } + return i; +} + +/*! Return true if octet-align is present and set to 1 in the given AMR related fmtp value. + * Default to octet-align=0, i.e. bandwidth-efficient mode. + * + * See RFC4867 "RTP Payload Format for AMR and AMR-WB" sections "8.1. AMR Media Type Registration" and "8.2. AMR-WB + * Media Type Registration": + * + * octet-align: Permissible values are 0 and 1. If 1, octet-align + * operation SHALL be used. If 0 or if not present, + * bandwidth-efficient operation is employed. + * + * https://tools.ietf.org/html/rfc4867 + */ +bool osmo_sdp_fmtp_amr_is_octet_aligned(const char *fmtp) +{ + return osmo_sdp_fmtp_get_int(fmtp, OSMO_SDP_NAME_AMR_OCTET_ALIGN, 0) == 1; +} diff --git a/src/libosmo-mgcp/Makefile.am b/src/libosmo-mgcp/Makefile.am index fa9a8eb..23c6b52 100644 --- a/src/libosmo-mgcp/Makefile.am +++ b/src/libosmo-mgcp/Makefile.am @@ -42,4 +42,5 @@ mgcp_ratectr.c \ mgcp_e1.c \ mgcp_iuup.c \ + $(top_srcdir)/src/libosmo-mgcp-client/fmtp.c \ $(NULL) -- To view, visit https://gerrit.osmocom.org/c/osmo-mgw/+/35434?usp=email To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-mgw Gerrit-Branch: master Gerrit-Change-Id: I3eaea353dbd98c19212199b564342d0ac16cbc07 Gerrit-Change-Number: 35434 Gerrit-PatchSet: 1 Gerrit-Owner: neels &lt;nhofmeyr(a)sysmocom.de&gt; Gerrit-MessageType: newchange