[PATCH] Fix encoding of padding bits to start with 0 bit

This patch is for fixing encoding of padding bits according to the 3gpp spec 44.060 section 11, wherein it shall always start with 0 bit followed with spare padding bits. During introduction of basic EGPRS feature new hex dump messages from a different working network log were used in Unit test. These exposed the issue of incorrect handling of padding bits encoding in osmo-pcu. Corrections in the existing test vector and new hex dump vectors shall be submitted in a separate patch. If only this patch is applied rlcmac testsuite will fail for few vectors. --- src/csn1.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/csn1.cpp b/src/csn1.cpp index 54cc411..82bf17f 100644 --- a/src/csn1.cpp +++ b/src/csn1.cpp @@ -2400,7 +2400,12 @@ gint16 csnStreamEncoder(csnStream_t* ar, const CSN_DESCR* pDescr, bitvec *vector guint8 bits_to_handle = remaining_bits_len%8; if (bits_to_handle > 0) { - guint8 fl = filler&(0xff>>(8-bits_to_handle)); + /* section 11 of 44.060 + * The padding bits may be the 'null' string. Otherwise, the + * padding bits starts with bit '0', followed by 'spare padding' + * < padding bits > ::= { null | 0 < spare padding > ! < Ignore : 1 bit** = < no string > > } ; + */ + guint8 fl = filler&(0xff>>(8-bits_to_handle + 1)); bitvec_write_field(vector, writeIndex, fl, bits_to_handle); LOGPC(DCSN1, LOGL_NOTICE, "%u|", fl); remaining_bits_len -= bits_to_handle; -- 1.7.9.5