falconia has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmo-abis/+/39625?usp=email )
Change subject: rtp2trau FR & EFR: disallow BFI in DL ......................................................................
rtp2trau FR & EFR: disallow BFI in DL
osmo_rtp2trau() accepts TW-TS-001 extended RTP payload format for FR and EFR, converting to either TRAU-DL or TRAU-UL. This extended format is required for TRAU-UL/TFO frame output, but it is also accepted for conversion to TRAU-DL in order to support the current form of OsmoMGW-E1 that has no TFO transform between RTP input and TDM-timed calls to osmo_rtp2trau().
TW-TS-001 can represent not only good frames, but also bad ones - however, bad frames on Abis are valid only in UL, not in DL. Prior to the present patch, if a BFI-marked frame were fed to osmo_rtp2trau() for conversion to TRAU-DL, the Bad Frame Indicator was dropped and the garbage payload bits were emitted as if they were a good frame - bad choice. Reject BFI frames in TRAU-DL mode, return -EINVAL.
Change-Id: Ic63943d4bde9902b27e4d8fe9a5fb6ccecbf36c6 --- M src/trau/trau_rtp_conv.c 1 file changed, 9 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/libosmo-abis refs/changes/25/39625/1
diff --git a/src/trau/trau_rtp_conv.c b/src/trau/trau_rtp_conv.c index 8d2631b..1114aaf 100644 --- a/src/trau/trau_rtp_conv.c +++ b/src/trau/trau_rtp_conv.c @@ -586,6 +586,10 @@ if ((data[0] & 0xF0) != 0xD0) return -EINVAL;
+ /* bad frames are only allowed in UL */ + if (bfi && tf->dir != OSMO_TRAU_DIR_UL) + return -EINVAL; + tf->type = OSMO_TRAU16_FT_FR;
/* FR Data Bits according to TS 48.060 Section 5.5.1.1.2 */ @@ -894,6 +898,10 @@ if ((data[0] & 0xF0) != 0xC0) return -EINVAL;
+ /* bad frames are only allowed in UL */ + if (bfi && tf->dir != OSMO_TRAU_DIR_UL) + return -EINVAL; + tf->type = OSMO_TRAU16_FT_EFR;
/* FR Data Bits according to TS 48.060 Section 5.5.1.1.2 */ @@ -1566,6 +1574,7 @@ * - RTP payload formats of RFC 5993, TW-TS-001 and TW-TS-002 are accepted * by the function - however, all metadata flags carried by the header octet * of these extended formats are ignored/dropped in the DL direction. + * BFI frames are not allowed in DL. * * - The most native RTP input formats for conversion to TRAU-DL are those * defined in ETSI TS 101 318 for FR, HR and EFR; the ones for FR and EFR
-
falconia