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DECT-NWK: Fix BCD encoded non byte aligned strings 

As proto_tree_add_bits_item does not support FT_STRING header fields
dissection of non byte aligned fields containing BCD values has been
rewritten using explicit reading of the BCD values and usage of
proto_tree_add_string
This commit is contained in:
Bernhard Dick 2022-12-28 13:17:11 +01:00 committed by Martin Mathieson
parent 4a0d7e9bbb
commit fefc28a743
1 changed files with 34 additions and 10 deletions
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44
epan/dissectors/packet-dect-nwk.c
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@ -1786,6 +1786,15 @@ static const value_string dect_charset_control_codes_val[] = {
/* TOOD: value_string for other protocols */
/* Encoding table for BCD string. */
/* TODO: Remove this when tvb_bcd_dig_to_str_be allows removing of last half byte */
static const dgt_set_t Dgt0_9_bcd = {
{
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
'0','1','2','3','4','5','6','7','8','9','?','?','?','?','?','?'
}
};
#define DECT_NWK_S_IE_OCTET_GROUP_EXTENSION_MASK 0x80
#define DECT_NWK_S_IE_OCTET_GROUP_EXTENSION_SHIFT 7
@ -2055,15 +2064,25 @@ static int dissect_dect_nwk_s_ie_multi_keypad(tvbuff_t *tvb, guint offset, guint
return offset;
}
static int dissect_dect_nwk_s_ie_portable_identity(tvbuff_t *tvb, guint offset, proto_tree *tree, void _U_ *data)
static int dissect_dect_nwk_s_ie_portable_identity(tvbuff_t *tvb, guint offset, packet_info *pinfo, proto_tree *tree, void _U_ *data)
{
guint8 value_length, identity_type, ipui_type;
guint bit_offset, no_of_bits;
guint bit_offset, no_of_bits, overflow_bits_in_last_byte, no_of_bytes;
gboolean bcd_last_byte_odd;
char* bcd_string;
identity_type = tvb_get_guint8(tvb, offset) & DECT_NWK_S_IE_PORTABLE_IDENTITY_TYPE_MASK;
proto_tree_add_item(tree, hf_dect_nwk_s_ie_portable_identity_type, tvb, offset, 1, ENC_NA);
offset++;
proto_tree_add_item(tree, hf_dect_nwk_s_ie_portable_identity_value_length, tvb, offset, 1, ENC_NA);
value_length = tvb_get_guint8(tvb, offset) & 0x7F;
overflow_bits_in_last_byte = value_length % 8;
if (overflow_bits_in_last_byte) {
no_of_bytes = value_length / 8 + 1;
bcd_last_byte_odd = true;
} else {
no_of_bytes = value_length / 8;
bcd_last_byte_odd = false;
}
offset++;
bit_offset = ( offset * 8 ) + 4;
switch(identity_type) {
@ -2083,27 +2102,32 @@ static int dissect_dect_nwk_s_ie_portable_identity(tvbuff_t *tvb, guint offset,
proto_tree_add_bits_item(tree, hf_dect_nwk_s_ie_portable_identity_ipui_p_acc, tvb, bit_offset + 16, no_of_bits - 16, ENC_BIG_ENDIAN);
break;
case DECT_NWK_IPUI_TYPE_Q:
proto_tree_add_bits_item(tree, hf_dect_nwk_s_ie_portable_identity_ipui_q_bacn, tvb, bit_offset, no_of_bits, ENC_BCD_DIGITS_0_9);
bcd_string = tvb_get_bcd_string(pinfo->pool, tvb, offset, no_of_bytes, &Dgt0_9_bcd, true, bcd_last_byte_odd, true);
proto_tree_add_string(tree, hf_dect_nwk_s_ie_portable_identity_ipui_q_bacn, tvb, offset, no_of_bytes, bcd_string);
break;
case DECT_NWK_IPUI_TYPE_R:
proto_tree_add_bits_item(tree, hf_dect_nwk_s_ie_portable_identity_ipui_r_imsi, tvb, bit_offset, no_of_bits, ENC_BCD_DIGITS_0_9);
bcd_string = tvb_get_bcd_string(pinfo->pool, tvb, offset, no_of_bytes, &Dgt0_9_bcd, true, bcd_last_byte_odd, true);
proto_tree_add_string(tree, hf_dect_nwk_s_ie_portable_identity_ipui_r_imsi, tvb, offset, no_of_bytes, bcd_string);
break;
case DECT_NWK_IPUI_TYPE_S:
proto_tree_add_bits_item(tree, hf_dect_nwk_s_ie_portable_identity_ipui_s_number, tvb, bit_offset, no_of_bits, ENC_BCD_DIGITS_0_9);
bcd_string = tvb_get_bcd_string(pinfo->pool, tvb, offset, no_of_bytes, &Dgt0_9_bcd, true, bcd_last_byte_odd, true);
proto_tree_add_string(tree, hf_dect_nwk_s_ie_portable_identity_ipui_s_number, tvb, offset, no_of_bytes, bcd_string);
break;
case DECT_NWK_IPUI_TYPE_T:
proto_tree_add_bits_item(tree, hf_dect_nwk_s_ie_portable_identity_ipui_t_eic, tvb, bit_offset, 16, ENC_BIG_ENDIAN);
proto_tree_add_bits_item(tree, hf_dect_nwk_s_ie_portable_identity_ipui_t_number, tvb, bit_offset + 16, no_of_bits - 16, ENC_BCD_DIGITS_0_9);
bcd_string = tvb_get_bcd_string(pinfo->pool, tvb, offset + 2, no_of_bytes - 2, &Dgt0_9_bcd, true, bcd_last_byte_odd, true);
proto_tree_add_string(tree, hf_dect_nwk_s_ie_portable_identity_ipui_t_number, tvb, offset + 2, no_of_bytes - 2, bcd_string);
break;
case DECT_NWK_IPUI_TYPE_U:
proto_tree_add_bits_item(tree, hf_dect_nwk_s_ie_portable_identity_ipui_u_cacn, tvb, bit_offset, no_of_bits, ENC_BCD_DIGITS_0_9);
bcd_string = tvb_get_bcd_string(pinfo->pool, tvb, offset, no_of_bytes, &Dgt0_9_bcd, true, bcd_last_byte_odd, true);
proto_tree_add_string(tree, hf_dect_nwk_s_ie_portable_identity_ipui_u_cacn, tvb, offset, no_of_bytes, bcd_string);
break;
}
bit_offset += no_of_bits;
offset += value_length / 8;
if (value_length % 8) {
no_of_bits = 8 - (value_length % 8);
if (overflow_bits_in_last_byte) {
no_of_bits = 8 - overflow_bits_in_last_byte;
proto_tree_add_bits_item(tree, hf_dect_nwk_s_ie_portable_identity_padding, tvb, bit_offset, no_of_bits, ENC_NA);
offset++;
}
@ -2569,7 +2593,7 @@ static int dissect_dect_nwk_s_ie(tvbuff_t *tvb, guint offset, packet_info *pinfo
offset = dissect_dect_nwk_s_ie_nwk_assigned_identity(tvb, offset, field_tree, data);
break;
case DECT_NWK_S_IE_PORTABLE_IDENTITY:
offset = dissect_dect_nwk_s_ie_portable_identity(tvb, offset, field_tree, data);
offset = dissect_dect_nwk_s_ie_portable_identity(tvb, offset, pinfo, field_tree, data);
break;
case DECT_NWK_S_IE_RAND:
proto_tree_add_item(field_tree,hf_dect_nwk_s_ie_rand_rand_field, tvb, offset, element_length, ENC_NA);