guint
packet_mpeg_sect_crc(tvbuff_t *tvb, packet_info *pinfo,
proto_tree *tree, guint start, guint end)
{
if (mpeg_sect_check_crc) {
proto_tree_add_checksum(tree, tvb, end, hf_mpeg_sect_crc, hf_mpeg_sect_crc_status, &ei_mpeg_sect_crc, pinfo, crc32_mpeg2_tvb_offset(tvb, start, end),
ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
} else {
proto_tree_add_checksum(tree, tvb, end, hf_mpeg_sect_crc, hf_mpeg_sect_crc_status, &ei_mpeg_sect_crc, pinfo, crc32_mpeg2_tvb_offset(tvb, start, end),
ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
}
return 4;
}
static void
dissect_stt_checksum(tvbuff_t *tvb, packet_info *pinfo, proto_tree *stt_tree)
{
gboolean can_checksum = !pinfo->fragmented &&
tvb_bytes_exist(tvb, 0, tvb_reported_length(tvb));
if (can_checksum && pref_check_checksum) {
vec_t cksum_vec[4];
guint32 phdr[2];
/* Set up the fields of the pseudo-header. */
SET_CKSUM_VEC_PTR(cksum_vec[0], (const guint8 *)pinfo->src.data,
pinfo->src.len);
SET_CKSUM_VEC_PTR(cksum_vec[1], (const guint8 *)pinfo->dst.data,
pinfo->dst.len);
switch (pinfo->src.type) {
case AT_IPv4:
phdr[0] = g_htonl((IP_PROTO_TCP<<16) + tvb_reported_length(tvb));
SET_CKSUM_VEC_PTR(cksum_vec[2], (const guint8 *)phdr, 4);
break;
case AT_IPv6:
phdr[0] = g_htonl(tvb_reported_length(tvb));
phdr[1] = g_htonl(IP_PROTO_TCP);
SET_CKSUM_VEC_PTR(cksum_vec[2], (const guint8 *)phdr, 8);
break;
default:
/* STT runs only atop IPv4 and IPv6.... */
DISSECTOR_ASSERT_NOT_REACHED();
break;
}
SET_CKSUM_VEC_TVB(cksum_vec[3], tvb, 0, tvb_reported_length(tvb));
proto_tree_add_checksum(stt_tree, tvb, 16, hf_stt_checksum, hf_stt_checksum_status, &ei_stt_checksum_bad, pinfo,
in_cksum(cksum_vec, 4), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
} else {
proto_tree_add_checksum(stt_tree, tvb, 16, hf_stt_checksum, hf_stt_checksum_status, &ei_stt_checksum_bad, pinfo,
0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
}
}
/** Checksums the data. */
static tvbuff_t *
checksum_data(tvbuff_t *tvb, proto_tree *tree)
{
int len = tvb_reported_length(tvb) - 2;
if (len < 0)
return tvb;
proto_tree_add_checksum(tree, tvb, len, hf_sir_fcs, hf_sir_fcs_status, NULL, NULL, crc16_ccitt_tvb(tvb, len),
ENC_LITTLE_ENDIAN, PROTO_CHECKSUM_VERIFY);
return tvb_new_subset_length(tvb, 0, len);
}
/* GFP has several identical 16 bit CRCs in its header (HECs). Note that
* this function increases the offset. */
static void
gfp_add_hec_tree(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint *offset, const guint len, const int field, const int field_status, expert_field *ei_bad)
{
guint hec_calc;
hec_calc = crc16_r3_ccitt_tvb(tvb, *offset, len);
*offset += len;
proto_tree_add_checksum(tree, tvb, *offset, field, field_status, ei_bad, pinfo, hec_calc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
*offset += 2;
}
static void
dissect_pe_checksum_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
{
proto_tree_add_checksum(parameter_tree, parameter_tvb, PE_CHECKSUM_OFFSET, hf_pe_checksum, -1, NULL, NULL, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
proto_item_append_text(parameter_item, " (0x%x)", tvb_get_ntohs(parameter_tvb, PE_CHECKSUM_OFFSET));
}
static int dissect_dvb_s2_bb(tvbuff_t *tvb, int cur_off, proto_tree *tree, packet_info *pinfo)
{
proto_item *ti;
proto_tree *dvb_s2_bb_tree;
guint8 input8, matype1;
guint16 input16, bb_data_len = 0, user_packet_length;
int sub_dissected = 0, flag_is_ms = 0, new_off = 0;
static const int * bb_header_bitfields[] = {
&hf_dvb_s2_bb_matype1_gs,
&hf_dvb_s2_bb_matype1_mis,
&hf_dvb_s2_bb_matype1_acm,
&hf_dvb_s2_bb_matype1_issyi,
&hf_dvb_s2_bb_matype1_npd,
&hf_dvb_s2_bb_matype1_ro,
NULL
};
col_append_str(pinfo->cinfo, COL_PROTOCOL, "BB ");
col_append_str(pinfo->cinfo, COL_INFO, "Baseband ");
/* create display subtree for the protocol */
ti = proto_tree_add_item(tree, proto_dvb_s2_bb, tvb, cur_off, DVB_S2_BB_HEADER_LEN, ENC_NA);
dvb_s2_bb_tree = proto_item_add_subtree(ti, ett_dvb_s2_bb);
matype1 = tvb_get_guint8(tvb, cur_off + DVB_S2_BB_OFFS_MATYPE1);
new_off += 1;
if (BIT_IS_CLEAR(matype1, DVB_S2_BB_MIS_POS))
flag_is_ms = 1;
proto_tree_add_bitmask_with_flags(dvb_s2_bb_tree, tvb, cur_off + DVB_S2_BB_OFFS_MATYPE1, hf_dvb_s2_bb_matype1,
ett_dvb_s2_bb_matype1, bb_header_bitfields, ENC_BIG_ENDIAN, BMT_NO_FLAGS);
input8 = tvb_get_guint8(tvb, cur_off + DVB_S2_BB_OFFS_MATYPE2);
new_off += 1;
if (flag_is_ms) {
proto_tree_add_uint_format_value(dvb_s2_bb_tree, hf_dvb_s2_bb_matype2, tvb,
cur_off + DVB_S2_BB_OFFS_MATYPE2, 1, input8, "Input Stream Identifier (ISI): %d",
input8);
} else {
proto_tree_add_uint_format_value(dvb_s2_bb_tree, hf_dvb_s2_bb_matype2, tvb,
cur_off + DVB_S2_BB_OFFS_MATYPE2, 1, input8, "reserved");
}
user_packet_length = input16 = tvb_get_ntohs(tvb, cur_off + DVB_S2_BB_OFFS_UPL);
new_off += 2;
proto_tree_add_uint_format(dvb_s2_bb_tree, hf_dvb_s2_bb_upl, tvb,
cur_off + DVB_S2_BB_OFFS_UPL, 2, input16, "User Packet Length: %d bits (%d bytes)",
(guint16) input16, (guint16) input16 / 8);
bb_data_len = input16 = tvb_get_ntohs(tvb, cur_off + DVB_S2_BB_OFFS_DFL);
bb_data_len /= 8;
new_off += 2;
proto_tree_add_uint_format_value(dvb_s2_bb_tree, hf_dvb_s2_bb_dfl, tvb,
cur_off + DVB_S2_BB_OFFS_DFL, 2, input16, "%d bits (%d bytes)", input16, input16 / 8);
new_off += 1;
proto_tree_add_item(dvb_s2_bb_tree, hf_dvb_s2_bb_sync, tvb, cur_off + DVB_S2_BB_OFFS_SYNC, 1, ENC_BIG_ENDIAN);
new_off += 2;
proto_tree_add_item(dvb_s2_bb_tree, hf_dvb_s2_bb_syncd, tvb, cur_off + DVB_S2_BB_OFFS_SYNCD, 2, ENC_BIG_ENDIAN);
new_off += 1;
proto_tree_add_checksum(dvb_s2_bb_tree, tvb, cur_off + DVB_S2_BB_OFFS_CRC, hf_dvb_s2_bb_crc, hf_dvb_s2_bb_crc_status, &ei_dvb_s2_bb_crc, pinfo,
compute_crc8(tvb, DVB_S2_BB_HEADER_LEN - 1, cur_off), ENC_NA, PROTO_CHECKSUM_VERIFY);
switch (matype1 & DVB_S2_BB_TSGS_MASK) {
case DVB_S2_BB_TSGS_GENERIC_CONTINUOUS:
/* Check GSE constraints on the BB header per 9.2.1 of ETSI TS 102 771 */
if (BIT_IS_SET(matype1, DVB_S2_BB_ISSYI_POS)) {
expert_add_info(pinfo, ti, &ei_dvb_s2_bb_issy_invalid);
}
if (BIT_IS_SET(matype1, DVB_S2_BB_NPD_POS)) {
expert_add_info(pinfo, ti, &ei_dvb_s2_bb_npd_invalid);
}
if (user_packet_length != 0x0000) {
expert_add_info_format(pinfo, ti, &ei_dvb_s2_bb_upl_invalid,
"UPL is 0x%04x. It must be 0x0000 for GSE packets.", user_packet_length);
}
while (bb_data_len) {
/* start DVB-GSE dissector */
sub_dissected = dissect_dvb_s2_gse(tvb, cur_off + new_off, tree, pinfo, bb_data_len);
new_off += sub_dissected;
if ((sub_dissected <= bb_data_len) && (sub_dissected >= DVB_S2_GSE_MINSIZE)) {
bb_data_len -= sub_dissected;
if (bb_data_len < DVB_S2_GSE_MINSIZE)
bb_data_len = 0;
} else {
bb_data_len = 0;
}
}
break;
case DVB_S2_BB_TSGS_GENERIC_PACKETIZED:
proto_tree_add_item(tree, hf_dvb_s2_bb_packetized, tvb, cur_off + new_off, bb_data_len, ENC_NA);
new_off += bb_data_len;
break;
case DVB_S2_BB_TSGS_TRANSPORT_STREAM:
proto_tree_add_item(tree, hf_dvb_s2_bb_transport, tvb, cur_off + new_off, bb_data_len, ENC_NA);
new_off += bb_data_len;
break;
default:
proto_tree_add_item(tree, hf_dvb_s2_bb_reserved, tvb, cur_off + new_off,bb_data_len, ENC_NA);
new_off += bb_data_len;
expert_add_info(pinfo, ti, &ei_dvb_s2_bb_reserved);
break;
}
return new_off;
}
static void
display_xip_serval(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_tree *xip_serval_tree;
proto_item *ti, *hl_ti;
tvbuff_t *next_tvb;
vec_t cksum_vec;
gint offset;
guint8 xsh_len, protocol, bytes_remaining;
/* Get XIP Serval header length, stored as number of 32-bit words. */
xsh_len = tvb_get_guint8(tvb, XSRVL_LEN) << 2;
/* Create XIP Serval header tree. */
ti = proto_tree_add_item(tree, proto_xip_serval, tvb,
0, xsh_len, ENC_NA);
xip_serval_tree = proto_item_add_subtree(ti, ett_xip_serval_tree);
/* Add XIP Serval header length. */
hl_ti = proto_tree_add_item(xip_serval_tree, hf_xip_serval_hl, tvb,
XSRVL_LEN, 1, ENC_BIG_ENDIAN);
proto_item_append_text(hl_ti, " bytes");
if (tvb_captured_length(tvb) < xsh_len)
expert_add_info_format(pinfo, hl_ti, &ei_xip_serval_bad_len,
"Header Length field (%d bytes) cannot be greater than actual number of bytes left in packet (%d bytes)",
xsh_len, tvb_captured_length(tvb));
/* Add XIP Serval protocol. If it's not data, TCP, or UDP, the
* packet is malformed.
*/
proto_tree_add_item(xip_serval_tree, hf_xip_serval_proto, tvb,
XSRVL_PRO, 1, ENC_BIG_ENDIAN);
protocol = tvb_get_guint8(tvb, XSRVL_PRO);
if (!try_val_to_str(protocol, xip_serval_proto_vals))
expert_add_info_format(pinfo, ti, &ei_xip_serval_bad_proto,
"Unrecognized protocol type: %d", protocol);
/* Compute checksum. */
SET_CKSUM_VEC_TVB(cksum_vec, tvb, 0, xsh_len);
proto_tree_add_checksum(xip_serval_tree, tvb, XSRVL_CHK, hf_xip_serval_check, -1, &ei_xip_serval_bad_checksum, pinfo, in_cksum(&cksum_vec, 1),
ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_IN_CKSUM);
offset = XSRVL_EXT;
/* If there's still more room, check for extension headers. */
bytes_remaining = xsh_len - offset;
while (bytes_remaining >= XIP_SERVAL_EXT_MIN_LEN) {
gint8 bytes_displayed = display_xip_serval_ext(tvb, pinfo, ti,
xip_serval_tree, offset);
/* Extension headers are malformed, so we can't say
* what the rest of the packet holds. Stop dissecting.
*/
if (bytes_displayed <= 0)
return;
offset += bytes_displayed;
bytes_remaining -= bytes_displayed;
}
switch (protocol) {
case XIP_SERVAL_PROTO_DATA:
next_tvb = tvb_new_subset_remaining(tvb, offset);
call_data_dissector(next_tvb, pinfo, tree);
break;
case IP_PROTO_TCP: {
/* Get the Data Offset field of the TCP header, which is
* the high nibble of the 12th octet and represents the
* size of the TCP header of 32-bit words.
*/
guint8 tcp_len = hi_nibble(tvb_get_guint8(tvb, offset + 12))*4;
next_tvb = tvb_new_subset(tvb, offset, tcp_len, tcp_len);
call_dissector(tcp_handle, next_tvb, pinfo, tree);
break;
}
case IP_PROTO_UDP:
/* The UDP header is always 8 bytes. */
next_tvb = tvb_new_subset(tvb, offset, 8, 8);
call_dissector(udp_handle, next_tvb, pinfo, tree);
break;
default:
break;
}
}