From eef45781024d6e17c7b473d15ec5d3d83515d0e2 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Mon, 21 Oct 2019 03:24:04 +0200 Subject: add sdp_msg API: SDP parsing/composition Rationale: in order to add full SDP to the MNCC protocol (upcoming patch I8c3b2de53ffae4ec3a66b9dabf308c290a2c999f), we need to parse and compose SDP messages. Obviously, libosmo-mgcp-client already contains similar code, but that is unfortunately heavily glued to the actual MGCP implementation. The simplest solution is to create this separate implementation, copy-pasting from the existing libosmo-mgcp-client code as is convenient. This API is added here to probe whether it works well. When it does, the intention is to "move it up" to osmo-mgw and overhaul the SDP parsing in our MGCP client and MGCP server APIs using this same API. Change-Id: If3ce23cd5bab15e2ab4c52ef3e4c75979dffe931 --- include/osmocom/msc/Makefile.am | 1 + include/osmocom/msc/sdp_msg.h | 68 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 69 insertions(+) create mode 100644 include/osmocom/msc/sdp_msg.h (limited to 'include') diff --git a/include/osmocom/msc/Makefile.am b/include/osmocom/msc/Makefile.am index 0d7d45ce9..faf1048dc 100644 --- a/include/osmocom/msc/Makefile.am +++ b/include/osmocom/msc/Makefile.am @@ -39,6 +39,7 @@ noinst_HEADERS = \ rrlp.h \ rtp_stream.h \ sccp_ran.h \ + sdp_msg.h \ sgs_iface.h \ sgs_server.h \ sgs_vty.h \ diff --git a/include/osmocom/msc/sdp_msg.h b/include/osmocom/msc/sdp_msg.h new file mode 100644 index 000000000..7ac6036f6 --- /dev/null +++ b/include/osmocom/msc/sdp_msg.h @@ -0,0 +1,68 @@ +/* Minimalistic SDP parse/compose API, focused on GSM audio codecs */ +#pragma once + +#include +#include + +extern const struct value_string sdp_msg_payload_type_names[]; +static inline const char *sdp_msg_payload_type_name(unsigned int payload_type) +{ return get_value_string(sdp_msg_payload_type_names, payload_type); } +int sdp_subtype_name_to_payload_type(const char *subtype_name); + +struct sdp_audio_codec { + unsigned int payload_type; + /* Like "GSM", "AMR", "EFR", ... */ + char subtype_name[16]; + unsigned int rate; + char fmtp[64]; +}; + +struct sdp_audio_codecs { + unsigned int count; + struct sdp_audio_codec codec[16]; +}; + +struct sdp_msg { + struct osmo_sockaddr_str rtp; + unsigned int ptime; + struct sdp_audio_codecs audio_codecs; +}; + +#define foreach_sdp_audio_codec(/* struct sdp_audio_codec* */ CODEC, \ + /* struct sdp_audio_codecs* */ AC) \ + for (CODEC = (AC)->codec; \ + (CODEC - (AC)->codec) < OSMO_MIN((AC)->count, ARRAY_SIZE((AC)->codec)); \ + CODEC++) + +const char *sdp_msg_line_end(const char *src); + +int sdp_audio_codec_cmp(const struct sdp_audio_codec *a, const struct sdp_audio_codec *b); + +struct sdp_audio_codec *sdp_audio_codec_add(struct sdp_audio_codecs *ac, unsigned int payload_type, + const char *subtype_name, unsigned int rate, const char *fmtp); +struct sdp_audio_codec *sdp_audio_codec_add_copy(struct sdp_audio_codecs *ac, + const struct sdp_audio_codec *codec); +int sdp_audio_codec_remove(struct sdp_audio_codecs *ac, const struct sdp_audio_codec *codec); +struct sdp_audio_codec *sdp_audio_codec_by_payload_type(struct sdp_audio_codecs *ac, + unsigned int payload_type, bool create); +struct sdp_audio_codec *sdp_audio_codec_by_descr(struct sdp_audio_codecs *ac, + const struct sdp_audio_codec *codec); + +void sdp_audio_codecs_intersection(struct sdp_audio_codecs *ac_dest, const struct sdp_audio_codecs *ac_other, + bool translate_payload_type_numbers); +void sdp_audio_codecs_select(struct sdp_audio_codecs *ac, struct sdp_audio_codec *codec); + +int sdp_msg_to_str(char *dst, size_t dst_size, const struct sdp_msg *sdp); +int sdp_msg_from_str(struct sdp_msg *sdp, const char *src); + +int sdp_audio_codec_name_buf(char *buf, size_t buflen, const struct sdp_audio_codec *codec); +char *sdp_audio_codec_name_c(void *ctx, const struct sdp_audio_codec *codec); +const char *sdp_audio_codec_name(const struct sdp_audio_codec *codec); + +int sdp_audio_codecs_name_buf(char *buf, size_t buflen, const struct sdp_audio_codecs *ac); +char *sdp_audio_codecs_name_c(void *ctx, const struct sdp_audio_codecs *ac); +const char *sdp_audio_codecs_name(const struct sdp_audio_codecs *ac); + +int sdp_msg_name_buf(char *buf, size_t buflen, const struct sdp_msg *sdp); +char *sdp_msg_name_c(void *ctx, const struct sdp_msg *sdp); +const char *sdp_msg_name(const struct sdp_msg *sdp); -- cgit v1.2.3