log: set L1 SAPI log context

Add a new common L1 SAPI enum, to unify all the BTS specific SAPIs.
Translate to this enum, and set the context for uplink messages in
each BTS specific implementation.

Set the context for downlink messages in the common l1sap code, by
converting the osmo_phsap_prim back to the SAPI value (mostly looking at
chan_nr). The new functions for doing this conversion,
get_common_sapi_by_trx_prim() and get_common_sapi_ph_data(), are based
on the existing to_gsmtap() and gsmtap_ph_data() functions.

Note that we can't set the uplink SAPI context in the common code,
because then we can't set it as early as possible. In this patch, the
SAPI context is set for the PHYs where the SAPI is readily available.
With additional conversion from the RSL channel, the SAPI context could
be set for osmo-bts-trx in a follow up patch.

Related: OS#2356
Depends: (libosmocore) I814cb3328d99faca9220adb5a80ffb934f219d7d
Change-Id: I6b7bb2e1d61502b61214f854a4ec5cbb7267545b

1 files changed, 82 insertions, 0 deletions

diff --git a/src/common/l1sap.c b/src/common/l1sap.c
index 2008f0e3..7c543804 100644
--- a/src/common/l1sap.c
+++ b/src/common/l1sap.c
@@ -257,6 +257,85 @@ int bts_check_for_ciph_cmd(struct msgb *msg, struct gsm_lchan *lchan,
 	return check_for_ciph_cmd(msg, lchan, chan_nr);
 }
 
+uint16_t l1sap_log_ctx_sapi;
+
+const struct value_string l1sap_common_sapi_names[] = {
+	{ L1SAP_COMMON_SAPI_UNKNOWN,	"UNKNOWN" },
+	/* alphabetic order */
+	{ L1SAP_COMMON_SAPI_AGCH,	"AGCH" },
+	{ L1SAP_COMMON_SAPI_BCCH,	"BCCH" },
+	{ L1SAP_COMMON_SAPI_CBCH,	"CBCH" },
+	{ L1SAP_COMMON_SAPI_FACCH_F,	"FACCH/F" },
+	{ L1SAP_COMMON_SAPI_FACCH_H,	"FACCH/H" },
+	{ L1SAP_COMMON_SAPI_FCCH,	"FCCH" },
+	{ L1SAP_COMMON_SAPI_IDLE,	"IDLE" },
+	{ L1SAP_COMMON_SAPI_NCH,	"NCH" },
+	{ L1SAP_COMMON_SAPI_PACCH,	"PACCH" },
+	{ L1SAP_COMMON_SAPI_PAGCH,	"PAGCH" },
+	{ L1SAP_COMMON_SAPI_PBCCH,	"PBCCH" },
+	{ L1SAP_COMMON_SAPI_PCH,	"PCH" },
+	{ L1SAP_COMMON_SAPI_PDTCH,	"PDTCH" },
+	{ L1SAP_COMMON_SAPI_PNCH,	"PNCH" },
+	{ L1SAP_COMMON_SAPI_PPCH,	"PPCH" },
+	{ L1SAP_COMMON_SAPI_PRACH,	"PRACH" },
+	{ L1SAP_COMMON_SAPI_PTCCH,	"PTCCH" },
+	{ L1SAP_COMMON_SAPI_RACH,	"RACH" },
+	{ L1SAP_COMMON_SAPI_SACCH,	"SACCH" },
+	{ L1SAP_COMMON_SAPI_SCH,	"SCH" },
+	{ L1SAP_COMMON_SAPI_SDCCH,	"SDCCH" },
+	{ L1SAP_COMMON_SAPI_TCH_F,	"TCH/F" },
+	{ L1SAP_COMMON_SAPI_TCH_H,	"TCH/H" },
+	{ 0, NULL }
+};
+
+static enum l1sap_common_sapi get_common_sapi_ph_data(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap)
+{
+	uint8_t link_id = l1sap->u.data.link_id;
+	uint8_t chan_nr = l1sap->u.data.chan_nr;
+	uint32_t u32Fn = l1sap->u.data.fn;
+
+	if (L1SAP_IS_CHAN_TCHF(chan_nr))
+		return L1SAP_COMMON_SAPI_TCH_F;
+
+	if (L1SAP_IS_CHAN_TCHH(chan_nr))
+		return L1SAP_COMMON_SAPI_TCH_H;
+
+	if (L1SAP_IS_CHAN_SDCCH4(chan_nr) || L1SAP_IS_CHAN_SDCCH8(chan_nr))
+		return L1SAP_COMMON_SAPI_SDCCH;
+
+	if (L1SAP_IS_CHAN_BCCH(chan_nr))
+		return L1SAP_COMMON_SAPI_BCCH;
+
+	if (L1SAP_IS_CHAN_AGCH_PCH(chan_nr))
+		/* The sapi depends on DSP configuration, not on the actual SYSTEM INFORMATION 3. */
+		return ((l1sap_fn2ccch_block(u32Fn) >= num_agch(trx, "PH-DATA-REQ"))
+			? L1SAP_COMMON_SAPI_PCH
+			: L1SAP_COMMON_SAPI_AGCH);
+
+	if (L1SAP_IS_CHAN_CBCH(chan_nr))
+		return L1SAP_COMMON_SAPI_CBCH;
+
+	if (L1SAP_IS_LINK_SACCH(link_id))
+		return L1SAP_COMMON_SAPI_SACCH;
+
+	return L1SAP_COMMON_SAPI_UNKNOWN;
+}
+
+static enum l1sap_common_sapi get_common_sapi_by_trx_prim(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap)
+{
+	/* Only downlink prims are relevant */
+	switch (OSMO_PRIM_HDR(&l1sap->oph)) {
+	case OSMO_PRIM(PRIM_PH_DATA, PRIM_OP_REQUEST):
+		if (ts_is_pdch(&trx->ts[L1SAP_CHAN2TS(l1sap->u.data.chan_nr)]))
+			return ((L1SAP_IS_PTCCH(l1sap->u.data.fn))
+				? L1SAP_COMMON_SAPI_PTCCH
+				: L1SAP_COMMON_SAPI_PDTCH);
+		return get_common_sapi_ph_data(trx, l1sap);
+	default:
+		return L1SAP_COMMON_SAPI_UNKNOWN;
+	}
+}
+
 struct gsmtap_inst *gsmtap = NULL;
 uint32_t gsmtap_sapi_mask = 0;
 uint8_t gsmtap_sapi_acch = 0;
@@ -1455,6 +1534,9 @@ int l1sap_up(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap)
 /* any L1 prim sent to bts model */
 static int l1sap_down(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap)
 {
+	l1sap_log_ctx_sapi = get_common_sapi_by_trx_prim(trx, l1sap);
+	log_set_context(LOG_CTX_L1_SAPI, &l1sap_log_ctx_sapi);
+
 	if (OSMO_PRIM_HDR(&l1sap->oph) ==
 				 OSMO_PRIM(PRIM_PH_DATA, PRIM_OP_REQUEST))
 		to_gsmtap(trx, l1sap);