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GTP: Minor reconstruction 

Extract Method for multiple message parsing for tpdus to simplify things for future bug fixes and to make the code logic clearer.
Encapsulate the following functions:
dissect_gtp_tpdu_by_handle
dissect_gtp_tpdu_as_pdcp_lte_info
dissect_gtp_tpsu_as_pdcp_nr_info
Note: The original code function is not changed.
This commit is contained in:
easonweii 2022-04-20 19:52:11 +08:00 committed by A Wireshark GitLab Utility
parent a73fd872ad
commit a1e0c34c30
1 changed files with 134 additions and 131 deletions
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265
epan/dissectors/packet-gtp.c
View File

@ -10084,6 +10084,129 @@ addRANContParameter(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gint of
call_dissector(nrup_handle, next_tvb, pinfo, tree);
}
static void
dissect_gtp_tpdu_by_handle(dissector_handle_t handle, tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree, int offset)
{
tvbuff_t *next_tvb;
next_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(handle, next_tvb, pinfo, tree);
col_prepend_fstr(pinfo->cinfo, COL_PROTOCOL, "GTP <");
col_append_str(pinfo->cinfo, COL_PROTOCOL, ">");
}
static void
dissect_gtp_tpdu_as_pdcp_lte_info(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree, gtp_hdr_t *gtp_hdr, int offset)
{
/* Check if we have info to call the PDCP dissector */
struct pdcp_lte_info *p_pdcp_info;
uat_pdcp_lte_keys_record_t * found_record;
tvbuff_t *pdcp_lte_tvb;
if ((found_record = look_up_pdcp_lte_keys_record(pinfo, (guint32)gtp_hdr->teid))) {
/* Look for attached packet info! */
p_pdcp_info = (struct pdcp_lte_info *)p_get_proto_data(wmem_file_scope(), pinfo, proto_pdcp_lte, 0);
/* If we don't have the data, add it */
if (p_pdcp_info == NULL) {
p_pdcp_info = wmem_new0(wmem_file_scope(), pdcp_lte_info);
/* Channel info is needed for RRC parsing */
/*p_pdcp_info->direction;*/
/*p_pdcp_info->ueid;*/
/*p_pdcp_info->channelType;*/
/*p_pdcp_info->channelId;*/
/*p_pdcp_info->BCCHTransport;*/
/* Details of PDCP header */
if (found_record->header_present == PDCP_LTE_HEADER_PRESENT) {
p_pdcp_info->no_header_pdu = FALSE;
} else {
p_pdcp_info->no_header_pdu = TRUE;
}
p_pdcp_info->plane = found_record->plane;
p_pdcp_info->seqnum_length = found_record->lte_sn_length;
/* RoHC settings */
p_pdcp_info->rohc.rohc_compression = found_record->rohc_compression;
p_pdcp_info->rohc.rohc_ip_version = 4; /* For now set it explicitly */
p_pdcp_info->rohc.cid_inclusion_info = FALSE;
p_pdcp_info->rohc.large_cid_present = FALSE;
p_pdcp_info->rohc.mode = MODE_NOT_SET;
p_pdcp_info->rohc.rnd = FALSE;
p_pdcp_info->rohc.udp_checksum_present = FALSE;
p_pdcp_info->rohc.profile = found_record->rohc_profile;
/* p_pdcp_info->is_retx;*/
/* Used by heuristic dissector only */
/*p_pdcp_info->pdu_length;*/
p_add_proto_data(wmem_file_scope(), pinfo, proto_pdcp_lte, 0, p_pdcp_info);
}
pdcp_lte_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(pdcp_lte_handle, pdcp_lte_tvb, pinfo, tree);
} else {
proto_tree_add_subtree(tree, tvb, offset, -1, ett_gtp_pdcp_no_conf, NULL, "[No PDCP-LTE Configuration data found]");
proto_tree_add_item(tree, hf_pdcp_cont, tvb, offset, -1, ENC_NA);
}
}
static void
dissect_gtp_tpsu_as_pdcp_nr_info(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree, gtp_hdr_t *gtp_hdr, int offset)
{
/*NR-U DUD or DDDS PDU
* This is NR-U DUD/DDDS PDU. It contains PDCP
* payload as per 3GPP TS 38.323
*/
/* Check if we have info to call the PDCP dissector */
uat_pdcp_nr_keys_record_t* found_record;
if ((found_record = look_up_pdcp_nr_keys_record(pinfo, (guint32)gtp_hdr->teid))) {
tvbuff_t *pdcp_tvb;
struct pdcp_nr_info temp_data;
pdcp_tvb = tvb_new_subset_remaining(tvb, offset);
/* Fill in pdcp_nr_info */
temp_data.direction = found_record->direction;
/*temp_data.ueid*/
/*temp_data.bearerType;*/
/*temp_data.bearerId;*/
/* Details of PDCP header */
temp_data.plane = found_record->plane;
temp_data.seqnum_length = found_record->pdcp_nr_sn_length;
/* PDCP_NR_(U|D)L_sdap_hdr_PRESENT bitmask */
if (found_record->sdap_header_present == PDCP_NR_SDAP_HEADER_PRESENT) {
if (temp_data.direction == PDCP_NR_DIRECTION_UPLINK) {
temp_data.sdap_header = PDCP_NR_UL_SDAP_HEADER_PRESENT;
} else {
temp_data.sdap_header = PDCP_NR_DL_SDAP_HEADER_PRESENT;
}
} else {
temp_data.sdap_header = 0;
}
temp_data.maci_present = found_record->mac_i_present;
/* RoHC settings */
temp_data.rohc.rohc_compression = found_record->rohc_compression;
temp_data.rohc.rohc_ip_version = 4; /* For now set it explicitly */
temp_data.rohc.cid_inclusion_info = FALSE;
temp_data.rohc.large_cid_present = FALSE;
temp_data.rohc.mode = MODE_NOT_SET;
temp_data.rohc.rnd = FALSE;
temp_data.rohc.udp_checksum_present = FALSE;
temp_data.rohc.profile = found_record->rohc_profile;
temp_data.is_retx = 0;
/* Used by heuristic dissector only */
temp_data.pdu_length = 0;
call_dissector_with_data(pdcp_nr_handle, pdcp_tvb, pinfo, tree, &temp_data);
} else {
proto_tree_add_subtree(tree, tvb, offset, -1, ett_gtp_pdcp_no_conf, NULL, "[No PDCP-NR Configuration data found]");
proto_tree_add_item(tree, hf_pdcp_cont, tvb, offset, -1, ENC_NA);
}
}
static int
dissect_gtp_common(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
@ -10102,7 +10225,6 @@ dissect_gtp_common(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
guint ext_hdr_length;
guint16 ext_hdr_pdcpsn;
gchar *tid_str;
tvbuff_t *next_tvb;
guint8 sub_proto;
guint8 acfield_len = 0;
gtp_msg_hash_t *gcrp = NULL;
@ -10657,21 +10779,18 @@ dissect_gtp_common(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
* 0x4f is excluded because PPP protocol type "IPv6 header compression"
* with protocol field compression is more likely than a plain IPv4 packet with 60 octet header size */
next_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(ip_handle, next_tvb, pinfo, tree);
dissect_gtp_tpdu_by_handle(ip_handle, tvb, pinfo, tree, offset);
} else if ((sub_proto & 0xf0) == 0x60) {
/* this is most likely an IPv6 packet */
next_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(ipv6_handle, next_tvb, pinfo, tree);
dissect_gtp_tpdu_by_handle(ipv6_handle, tvb, pinfo, tree, offset);
} else {
if (tvb_reported_length_remaining(tvb, offset)>14) {
guint16 eth_type;
eth_type = tvb_get_ntohs(tvb, offset+12);
if (eth_type == ETHERTYPE_ARP || eth_type == ETHERTYPE_IPv6 || eth_type == ETHERTYPE_IP) {
/* guess this is an ethernet PDU based on the eth type field */
next_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(eth_handle, next_tvb, pinfo, tree);
dissect_gtp_tpdu_by_handle(eth_handle, tvb, pinfo, tree, offset);
}
} else {
#if 0
@ -10691,145 +10810,29 @@ dissect_gtp_common(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
call_dissector(ppp_handle, next_tvb, pinfo, tree);
#endif
proto_tree_add_item(tree, hf_gtp_tpdu_data, tvb, offset, -1, ENC_NA);
col_prepend_fstr(pinfo->cinfo, COL_PROTOCOL, "GTP <");
col_append_str(pinfo->cinfo, COL_PROTOCOL, ">");
}
}
col_prepend_fstr(pinfo->cinfo, COL_PROTOCOL, "GTP <");
col_append_str(pinfo->cinfo, COL_PROTOCOL, ">");
break;
case GTP_TPDU_AS_PDCP_LTE:
if (tvb_reported_length_remaining(tvb, offset) > 0) {
/* Check if we have info to call the PDCP dissector */
struct pdcp_lte_info *p_pdcp_info;
uat_pdcp_lte_keys_record_t * found_record;
tvbuff_t *pdcp_lte_tvb;
if ((found_record = look_up_pdcp_lte_keys_record(pinfo, (guint32)gtp_hdr->teid))) {
/* Look for attached packet info! */
p_pdcp_info = (struct pdcp_lte_info *)p_get_proto_data(wmem_file_scope(), pinfo, proto_pdcp_lte, 0);
/* If we don't have the data, add it */
if (p_pdcp_info == NULL) {
p_pdcp_info = wmem_new0(wmem_file_scope(), pdcp_lte_info);
/* Channel info is needed for RRC parsing */
/*p_pdcp_info->direction;*/
/*p_pdcp_info->ueid;*/
/*p_pdcp_info->channelType;*/
/*p_pdcp_info->channelId;*/
/*p_pdcp_info->BCCHTransport;*/
/* Details of PDCP header */
if (found_record->header_present == PDCP_LTE_HEADER_PRESENT) {
p_pdcp_info->no_header_pdu = FALSE;
} else {
p_pdcp_info->no_header_pdu = TRUE;
}
p_pdcp_info->plane = found_record->plane;
p_pdcp_info->seqnum_length = found_record->lte_sn_length;
/* RoHC settings */
p_pdcp_info->rohc.rohc_compression = found_record->rohc_compression;
p_pdcp_info->rohc.rohc_ip_version = 4; /* For now set it explicitly */
p_pdcp_info->rohc.cid_inclusion_info = FALSE;
p_pdcp_info->rohc.large_cid_present = FALSE;
p_pdcp_info->rohc.mode = MODE_NOT_SET;
p_pdcp_info->rohc.rnd = FALSE;
p_pdcp_info->rohc.udp_checksum_present = FALSE;
p_pdcp_info->rohc.profile = found_record->rohc_profile;
/* p_pdcp_info->is_retx;*/
/* Used by heuristic dissector only */
/*p_pdcp_info->pdu_length;*/
p_add_proto_data(wmem_file_scope(), pinfo, proto_pdcp_lte, 0, p_pdcp_info);
}
pdcp_lte_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(pdcp_lte_handle, pdcp_lte_tvb, pinfo, tree);
} else {
proto_tree_add_subtree(tree, tvb, offset, -1, ett_gtp_pdcp_no_conf, NULL, "[No PDCP-LTE Configuration data found]");
proto_tree_add_item(tree, hf_pdcp_cont, tvb, offset, -1, ENC_NA);
}
}
dissect_gtp_tpdu_as_pdcp_lte_info(tvb, pinfo, tree, gtp_hdr, offset);
break;
case GTP_TPDU_AS_PDCP_NR:
if (tvb_reported_length_remaining(tvb, offset) > 0) {
/*NR-U DUD or DDDS PDU
* This is NR-U DUD/DDDS PDU. It contains PDCP
* payload as per 3GPP TS 38.323
*/
/* Check if we have info to call the PDCP dissector */
uat_pdcp_nr_keys_record_t* found_record;
if ((found_record = look_up_pdcp_nr_keys_record(pinfo, (guint32)gtp_hdr->teid))) {
tvbuff_t *pdcp_tvb;
struct pdcp_nr_info temp_data;
pdcp_tvb = tvb_new_subset_remaining(tvb, offset);
/* Fill in pdcp_nr_info */
temp_data.direction = found_record->direction;
/*temp_data.ueid*/
/*temp_data.bearerType;*/
/*temp_data.bearerId;*/
/* Details of PDCP header */
temp_data.plane = found_record->plane;
temp_data.seqnum_length = found_record->pdcp_nr_sn_length;
/* PDCP_NR_(U|D)L_sdap_hdr_PRESENT bitmask */
if (found_record->sdap_header_present == PDCP_NR_SDAP_HEADER_PRESENT) {
if (temp_data.direction == PDCP_NR_DIRECTION_UPLINK) {
temp_data.sdap_header = PDCP_NR_UL_SDAP_HEADER_PRESENT;
} else {
temp_data.sdap_header = PDCP_NR_DL_SDAP_HEADER_PRESENT;
}
} else {
temp_data.sdap_header = 0;
}
temp_data.maci_present = found_record->mac_i_present;
/* RoHC settings */
temp_data.rohc.rohc_compression = found_record->rohc_compression;
temp_data.rohc.rohc_ip_version = 4; /* For now set it explicitly */
temp_data.rohc.cid_inclusion_info = FALSE;
temp_data.rohc.large_cid_present = FALSE;
temp_data.rohc.mode = MODE_NOT_SET;
temp_data.rohc.rnd = FALSE;
temp_data.rohc.udp_checksum_present = FALSE;
temp_data.rohc.profile = found_record->rohc_profile;
temp_data.is_retx = 0;
/* Used by heuristic dissector only */
temp_data.pdu_length = 0;
call_dissector_with_data(pdcp_nr_handle, pdcp_tvb, pinfo, tree, &temp_data);
} else {
proto_tree_add_subtree(tree, tvb, offset, -1, ett_gtp_pdcp_no_conf, NULL, "[No PDCP-NR Configuration data found]");
proto_tree_add_item(tree, hf_pdcp_cont, tvb, offset, -1, ENC_NA);
}
}
dissect_gtp_tpsu_as_pdcp_nr_info(tvb, pinfo, tree, gtp_hdr, offset);
break;
case GTP_TPDU_AS_SYNC:
next_tvb = tvb_new_subset_remaining(tvb, offset + acfield_len);
call_dissector(sync_handle, next_tvb, pinfo, tree);
col_prepend_fstr(pinfo->cinfo, COL_PROTOCOL, "GTP <");
col_append_str(pinfo->cinfo, COL_PROTOCOL, ">");
dissect_gtp_tpdu_by_handle(sync_handle, tvb, pinfo, tree, offset + acfield_len);
break;
case GTP_TPDU_AS_ETHERNET:
next_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(eth_handle, next_tvb, pinfo, tree);
col_prepend_fstr(pinfo->cinfo, COL_PROTOCOL, "GTP <");
col_append_str(pinfo->cinfo, COL_PROTOCOL, ">");
dissect_gtp_tpdu_by_handle(eth_handle, tvb, pinfo, tree, offset);
break;
case GTP_TPDU_AS_CUSTOM:
/* Call a custom dissector if available */
if (gtp_tpdu_custom_handle ||
(gtp_tpdu_custom_handle = find_dissector("gtp_tpdu_custom"))) {
next_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(gtp_tpdu_custom_handle, next_tvb, pinfo, tree);
col_prepend_fstr(pinfo->cinfo, COL_PROTOCOL, "GTP <");
col_append_str(pinfo->cinfo, COL_PROTOCOL, ">");
dissect_gtp_tpdu_by_handle(gtp_tpdu_custom_handle, tvb, pinfo, tree, offset);
} else {
proto_tree_add_item(tree, hf_gtp_tpdu_data, tvb, offset, -1, ENC_NA);
}