diff options
Diffstat (limited to 'src/libmsc/cc_sdp.c')
| -rw-r--r-- | src/libmsc/cc_sdp.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/src/libmsc/cc_sdp.c b/src/libmsc/cc_sdp.c new file mode 100644 index 000000000..eeb9ab640 --- /dev/null +++ b/src/libmsc/cc_sdp.c @@ -0,0 +1,179 @@ +#include <osmocom/gsm/protocol/gsm_08_08.h> + +#include <osmocom/msc/cc_sdp.h> +#include <osmocom/msc/codec_sdp_cc_t9n.h> +#include <osmocom/msc/debug.h> + +/* Add all known payload types encountered in GSM networks */ +static void sdp_add_all_mobile_codecs(struct sdp_audio_codecs *ac) +{ + /* In order of preference. TODO: make configurable */ + static const enum gsm48_bcap_speech_ver mobile_codecs[] = { + GSM48_BCAP_SV_AMR_F /*!< 4 GSM FR V3 (FR AMR) */, + GSM48_BCAP_SV_AMR_H /*!< 5 GSM HR V3 (HR_AMR) */, + GSM48_BCAP_SV_EFR /*!< 2 GSM FR V2 (GSM EFR) */, + GSM48_BCAP_SV_FR /*!< 0 GSM FR V1 (GSM FR) */, + GSM48_BCAP_SV_HR /*!< 1 GSM HR V1 (GSM HR) */, + }; + int i; + for (i = 0; i < ARRAY_SIZE(mobile_codecs); i++) + sdp_audio_codecs_add_speech_ver(ac, mobile_codecs[i]); +} + +/* Add all known AMR payload types encountered in UTRAN networks */ +static void sdp_add_all_utran_codecs(struct sdp_audio_codecs *ac) +{ + /* In order of preference. TODO: make configurable */ + static const enum gsm48_bcap_speech_ver utran_codecs[] = { + GSM48_BCAP_SV_AMR_F /*!< 4 GSM FR V3 (FR AMR) */, + GSM48_BCAP_SV_AMR_H /*!< 5 GSM HR V3 (HR_AMR) */, + GSM48_BCAP_SV_AMR_OH /*!< 11 GSM HR V6 (OHR AMR) */, + GSM48_BCAP_SV_AMR_FW /*!< 8 GSM FR V5 (FR AMR-WB) */, + GSM48_BCAP_SV_AMR_OFW /*!< 6 GSM FR V4 (OFR AMR-WB) */, + GSM48_BCAP_SV_AMR_OHW /*!< 7 GSM HR V4 (OHR AMR-WB) */, + }; + int i; + for (i = 0; i < ARRAY_SIZE(utran_codecs); i++) + sdp_audio_codecs_add_speech_ver(ac, utran_codecs[i]); +} + +static void cc_sdp_set_ran(struct cc_sdp *cc_sdp, enum osmo_rat_type ran_type) +{ + cc_sdp->ran = (struct sdp_audio_codecs){}; + + switch (ran_type) { + default: + case OSMO_RAT_GERAN_A: + sdp_add_all_mobile_codecs(&cc_sdp->ran); + break; + + case OSMO_RAT_UTRAN_IU: + sdp_add_all_utran_codecs(&cc_sdp->ran); + break; + } +} + +void cc_sdp_init(struct cc_sdp *cc_sdp, + enum osmo_rat_type ran_type, + const struct gsm_mncc_bearer_cap *ms_bearer_cap, + const struct gsm0808_speech_codec_list *codec_list_bss_supported) +{ + *cc_sdp = (struct cc_sdp){}; + cc_sdp_set_ran(cc_sdp, ran_type); + + if (ms_bearer_cap) + sdp_audio_codecs_from_bearer_cap(&cc_sdp->ms, ms_bearer_cap); + + if (codec_list_bss_supported) + cc_sdp_set_cell(cc_sdp, codec_list_bss_supported); +} + +void cc_sdp_set_cell(struct cc_sdp *cc_sdp, + const struct gsm0808_speech_codec_list *codec_list_bss_supported) +{ + cc_sdp->cell = (struct sdp_audio_codecs){}; + if (codec_list_bss_supported) + sdp_audio_codecs_from_speech_codec_list(&cc_sdp->cell, codec_list_bss_supported); +} + +/* Render intersections of all known audio codec constraints to reach a resulting choice of favorite audio codec, plus + * possible set of alternative audio codecs, in cc_sdp->result. (The result.rtp address remains unchanged.) */ +int cc_sdp_filter(struct cc_sdp *cc_sdp) +{ + struct sdp_audio_codecs *r = &cc_sdp->result.audio_codecs; + struct sdp_audio_codec *a = &cc_sdp->assignment; + *r = cc_sdp->ran; + if (cc_sdp->ms.count) + sdp_audio_codecs_intersection(r, &cc_sdp->ms, false); + if (cc_sdp->cell.count) + sdp_audio_codecs_intersection(r, &cc_sdp->cell, false); + if (cc_sdp->remote.audio_codecs.count) + sdp_audio_codecs_intersection(r, &cc_sdp->remote.audio_codecs, true); + +#if ALLOW_REASSIGNMENT + /* If osmo-msc were able to trigger a re-assignment after the remote side has picked a codec mismatching the + * initial Assignment, then this code here would make sense: keep the other codecs as available to choose from, + * but put the currently assigned codec in the first position. */ + if (a->subtype_name[0]) { + /* Assignment has completed, the chosen codec should be the first of the resulting SDP. + * Make sure this is actually listed in the result SDP and move to first place. */ + struct sdp_audio_codec *select = sdp_audio_codec_by_descr(r, a); + + if (!select) { + /* Not present. Add. */ + if (sdp_audio_codec_by_payload_type(r, a->payload_type, false)) { + /* Oh crunch, that payload type number is already in use. + * Find an unused one. */ + for (a->payload_type = 96; a->payload_type <= 127; a->payload_type++) { + if (!sdp_audio_codec_by_payload_type(r, a->payload_type, false)) + break; + } + + if (a->payload_type > 127) + return -ENOSPC; + } + select = sdp_audio_codec_add_copy(r, a); + } + + sdp_audio_codecs_select(r, select); + } +#else + /* Currently, osmo-msc does not trigger re-assignment if the remote side has picked a codec that the local side + * would also support, but the local side has already assigned a mismatching codec before. Mismatching codecs + * means call failure. So, currently, if locally, Assignment has already happened, it makes sense to send only + * the assigned codec as available choice to the remote side. */ + if (a->subtype_name[0]) { + /* Assignment has completed, the chosen codec should be the the only possible one. */ + struct sdp_audio_codecs assigned_codec = {}; + sdp_audio_codec_add_copy(&assigned_codec, a); + sdp_audio_codecs_intersection(r, &assigned_codec, false); + } +#endif + return 0; +} + +int cc_sdp_name_buf(char *buf, size_t buflen, const struct cc_sdp *cc_sdp) +{ + struct osmo_strbuf sb = { .buf = buf, .len = buflen }; + OSMO_STRBUF_PRINTF(sb, "RAN={"); + OSMO_STRBUF_APPEND(sb, sdp_audio_codecs_name_buf, &cc_sdp->ran); + OSMO_STRBUF_PRINTF(sb, "}"); + + if (cc_sdp->cell.count) { + OSMO_STRBUF_PRINTF(sb, " cell={"); + OSMO_STRBUF_APPEND(sb, sdp_audio_codecs_name_buf, &cc_sdp->cell); + OSMO_STRBUF_PRINTF(sb, "}"); + } + + if (cc_sdp->ms.count) { + OSMO_STRBUF_PRINTF(sb, " MS={"); + OSMO_STRBUF_APPEND(sb, sdp_audio_codecs_name_buf, &cc_sdp->ms); + OSMO_STRBUF_PRINTF(sb, "}"); + } + + if (cc_sdp->remote.audio_codecs.count + || osmo_sockaddr_str_is_nonzero(&cc_sdp->remote.rtp)) { + OSMO_STRBUF_PRINTF(sb, " remote="); + OSMO_STRBUF_APPEND(sb, sdp_msg_name_buf, &cc_sdp->remote); + } + + if (cc_sdp->assignment.subtype_name[0]) { + OSMO_STRBUF_PRINTF(sb, " assigned="); + OSMO_STRBUF_APPEND(sb, sdp_audio_codec_name_buf, &cc_sdp->assignment); + } + + OSMO_STRBUF_PRINTF(sb, " result="); + OSMO_STRBUF_APPEND(sb, sdp_msg_name_buf, &cc_sdp->result); + + return sb.chars_needed; +} + +char *cc_sdp_name_c(void *ctx, const struct cc_sdp *cc_sdp) +{ + OSMO_NAME_C_IMPL(ctx, 128, "cc_sdp_name_c-ERROR", cc_sdp_name_buf, cc_sdp) +} + +const char *cc_sdp_name(const struct cc_sdp *cc_sdp) +{ + return cc_sdp_name_c(OTC_SELECT, cc_sdp); +} |