gsmtap: Solve TCH / FACCH confusion once and for all
* What we used to call TCH/F and TCH/H in gsmtap are actually only
FACCH/F and FACCH/H, i.e. the signaling part of Bm/Lm channels
* Give them proper names with backwards compatibility #define
* Split VOICE into VOICE_F and VOICE_H. If we don't differentiate this,
a receiver is not able to determine the RSL channel ID of a frame
without looking at external state/context. That in turn has been a
design feature of GSMTAP Um format so far, and programs like
osmo-bts-virtual rely on it.
Change-Id: I952044a17334f35712e087dc41781805000aebc1
Related: OS#2557
diff --git a/src/gsmtap_util.c b/src/gsmtap_util.c
index 40ec4b8..9a0ac02 100644
--- a/src/gsmtap_util.c
+++ b/src/gsmtap_util.c
@@ -54,18 +54,25 @@
/*! convert RSL channel number to GSMTAP channel type
* \param[in] rsl_chantype RSL channel type
* \param[in] link_id RSL link identifier
+ * \param[in] user_plane Is this voice/csd user plane (1) or signaling (0)
* \returns GSMTAP channel type
*/
-uint8_t chantype_rsl2gsmtap(uint8_t rsl_chantype, uint8_t link_id)
+uint8_t chantype_rsl2gsmtap2(uint8_t rsl_chantype, uint8_t link_id, bool user_plane)
{
uint8_t ret = GSMTAP_CHANNEL_UNKNOWN;
switch (rsl_chantype) {
case RSL_CHAN_Bm_ACCHs:
- ret = GSMTAP_CHANNEL_TCH_F;
+ if (user_plane)
+ ret = GSMTAP_CHANNEL_VOICE_F;
+ else
+ ret = GSMTAP_CHANNEL_FACCH_F;
break;
case RSL_CHAN_Lm_ACCHs:
- ret = GSMTAP_CHANNEL_TCH_H;
+ if (user_plane)
+ ret = GSMTAP_CHANNEL_VOICE_H;
+ else
+ ret = GSMTAP_CHANNEL_FACCH_H;
break;
case RSL_CHAN_SDCCH4_ACCH:
ret = GSMTAP_CHANNEL_SDCCH4;
@@ -100,6 +107,16 @@
return ret;
}
+/*! convert RSL channel number to GSMTAP channel type
+ * \param[in] rsl_chantype RSL channel type
+ * \param[in] link_id RSL link identifier
+ * \returns GSMTAP channel type
+ */
+uint8_t chantype_rsl2gsmtap(uint8_t rsl_chantype, uint8_t link_id)
+{
+ return chantype_rsl2gsmtap2(rsl_chantype, link_id, false);
+}
+
/*! convert GSMTAP channel type to RSL channel number + Link ID
* \param[in] gsmtap_chantype GSMTAP channel type
* \param[out] rsl_chantype RSL channel mumber
@@ -109,10 +126,12 @@
uint8_t *link_id)
{
switch (gsmtap_chantype & ~GSMTAP_CHANNEL_ACCH & 0xff) {
- case GSMTAP_CHANNEL_TCH_F: // TCH/F, FACCH/F
+ case GSMTAP_CHANNEL_FACCH_F:
+ case GSMTAP_CHANNEL_VOICE_F: // TCH/F
*rsl_chantype = RSL_CHAN_Bm_ACCHs;
break;
- case GSMTAP_CHANNEL_TCH_H: // TCH/H, FACCH/H
+ case GSMTAP_CHANNEL_FACCH_H:
+ case GSMTAP_CHANNEL_VOICE_H: // TCH/H
*rsl_chantype = RSL_CHAN_Lm_ACCHs;
break;
case GSMTAP_CHANNEL_SDCCH4: // SDCCH/4
@@ -467,8 +486,8 @@
{ GSMTAP_CHANNEL_SDCCH, "SDCCH" },
{ GSMTAP_CHANNEL_SDCCH4, "SDCCH/4" },
{ GSMTAP_CHANNEL_SDCCH8, "SDCCH/8" },
- { GSMTAP_CHANNEL_TCH_F, "TCH/F/FACCH/F" },
- { GSMTAP_CHANNEL_TCH_H, "TCH/H/FACCH/H" },
+ { GSMTAP_CHANNEL_FACCH_F, "FACCH/F" },
+ { GSMTAP_CHANNEL_FACCH_H, "FACCH/H" },
{ GSMTAP_CHANNEL_PACCH, "PACCH" },
{ GSMTAP_CHANNEL_CBCH52, "CBCH" },
{ GSMTAP_CHANNEL_PDCH, "PDCH" } ,
@@ -477,9 +496,10 @@
{ GSMTAP_CHANNEL_ACCH | GSMTAP_CHANNEL_SDCCH, "LSACCH" },
{ GSMTAP_CHANNEL_ACCH | GSMTAP_CHANNEL_SDCCH4, "SACCH/4" },
{ GSMTAP_CHANNEL_ACCH | GSMTAP_CHANNEL_SDCCH8, "SACCH/8" },
- { GSMTAP_CHANNEL_ACCH | GSMTAP_CHANNEL_TCH_F, "SACCH/F" },
- { GSMTAP_CHANNEL_ACCH | GSMTAP_CHANNEL_TCH_H, "SACCH/H" },
- { GSMTAP_CHANNEL_VOICE, "VOICE" },
+ { GSMTAP_CHANNEL_ACCH | GSMTAP_CHANNEL_FACCH_F, "SACCH/F" },
+ { GSMTAP_CHANNEL_ACCH | GSMTAP_CHANNEL_FACCH_H, "SACCH/H" },
+ { GSMTAP_CHANNEL_VOICE_F, "TCH/F" },
+ { GSMTAP_CHANNEL_VOICE_H, "TCH/H" },
{ 0, NULL }
};