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IEEE1722 AVTP: Support UDP/IP Encapsulation 

Fix support for IEEE 1722-2016 Annex J IP Encapsulation.
Dissect extra 4-octet encapsulation_sequence_num field that
is present when carried on UDP/IP. Perform rudimentary sequence
analysis with it. Fix #17389.
This commit is contained in:
John Thacker 2021-09-03 07:50:29 -04:00 committed by Wireshark GitLab Utility
parent 22768e218c
commit d5a3824f54
1 changed files with 92 additions and 7 deletions
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99
epan/dissectors/packet-ieee1722.c
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@ -37,9 +37,11 @@
#include "config.h"
#include <epan/packet.h>
#include <epan/conversation.h>
#include <epan/expert.h>
#include <epan/etypes.h>
#include <epan/decode_as.h>
#include <epan/proto_data.h>
#include <epan/dissectors/packet-socketcan.h>
void proto_register_1722(void);
@ -66,7 +68,16 @@ void proto_reg_handoff_1722_acf_lin(void);
static dissector_handle_t jpeg_handle;
static dissector_handle_t h264_handle;
#define UDP_PORT_IEEE_1722 17220
#define UDP_PORT_IEEE_1722 17220 /* One of two IANA registered ports */
enum IEEE_1722_TRANSPORT {
IEEE_1722_TRANSPORT_ETH,
IEEE_1722_TRANSPORT_UDP,
};
typedef struct _ieee1722_seq_data_t {
guint32 seqnum_exp;
} ieee1722_seq_data_t;
/**************************************************************************************************/
/* 1722 */
@ -329,6 +340,7 @@ static const range_string subtype_range_rvals[] = {
/* Initialize the protocol and registered fields */
static int proto_1722 = -1;
static int hf_1722_encap_seqnum = -1;
static int hf_1722_subtype = -1;
static int hf_1722_svfield = -1;
static int hf_1722_verfield = -1;
@ -336,6 +348,9 @@ static int hf_1722_verfield = -1;
/* Initialize the subtree pointers */
static int ett_1722 = -1;
static expert_field ei_1722_encap_seqnum_dup = EI_INIT;
static expert_field ei_1722_encap_seqnum_ooo = EI_INIT;
static dissector_table_t avb_dissector_table;
/**************************************************************************************************/
@ -809,10 +824,40 @@ static dissector_table_t avb1722_acf_lin_dissector_table;
/* 1722 dissector implementation */
/* */
/**************************************************************************************************/
static int dissect_1722(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
static guint32
get_seqnum_exp_1722_udp(packet_info *pinfo, const guint32 seqnum)
{
conversation_t *conv;
ieee1722_seq_data_t *conv_seq_data, *p_seq_data;
if (!PINFO_FD_VISITED(pinfo)) {
conv = find_or_create_conversation(pinfo);
conv_seq_data = (ieee1722_seq_data_t *)conversation_get_proto_data(conv, proto_1722);
if (conv_seq_data == NULL) {
conv_seq_data = wmem_new(wmem_file_scope(), ieee1722_seq_data_t);
conv_seq_data->seqnum_exp = seqnum;
conversation_add_proto_data(conv, proto_1722, conv_seq_data);
} else {
conv_seq_data->seqnum_exp++;
}
p_seq_data = wmem_new(wmem_file_scope(), ieee1722_seq_data_t);
p_seq_data->seqnum_exp = conv_seq_data->seqnum_exp;
p_add_proto_data(wmem_file_scope(), pinfo, proto_1722, 0, p_seq_data);
} else {
p_seq_data = (ieee1722_seq_data_t *)p_get_proto_data(wmem_file_scope(), pinfo, proto_1722, 0);
}
DISSECTOR_ASSERT(p_seq_data != NULL);
return p_seq_data->seqnum_exp;
}
static int dissect_1722_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, enum IEEE_1722_TRANSPORT transport)
{
proto_item *ti;
proto_tree *ieee1722_tree;
guint32 encap_seqnum, encap_seqnum_exp;
guint subtype = 0;
gint offset = 0;
int dissected_size;
@ -828,6 +873,20 @@ static int dissect_1722(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, voi
ti = proto_tree_add_item(tree, proto_1722, tvb, 0, -1, ENC_NA);
ieee1722_tree = proto_item_add_subtree(ti, ett_1722);
if (transport == IEEE_1722_TRANSPORT_UDP) {
/* IEEE 1722-2016 Annex J IP Encapsulation */
ti = proto_tree_add_item_ret_uint(ieee1722_tree, hf_1722_encap_seqnum, tvb, offset, 4, ENC_BIG_ENDIAN, &encap_seqnum);
encap_seqnum_exp = get_seqnum_exp_1722_udp(pinfo, encap_seqnum);
if (encap_seqnum != encap_seqnum_exp) {
if ((encap_seqnum + 1) == encap_seqnum_exp) {
expert_add_info(pinfo, ti, &ei_1722_encap_seqnum_dup);
} else {
expert_add_info(pinfo, ti, &ei_1722_encap_seqnum_ooo);
}
}
offset += 4;
}
proto_tree_add_item_ret_uint(ieee1722_tree, hf_1722_subtype, tvb, offset, 1, ENC_BIG_ENDIAN, &subtype);
offset += 1;
proto_tree_add_bitmask_list(ieee1722_tree, tvb, offset, 1, fields, ENC_NA);
@ -842,10 +901,25 @@ static int dissect_1722(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, voi
return tvb_captured_length(tvb);
}
static int dissect_1722_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
return dissect_1722_common(tvb, pinfo, tree, IEEE_1722_TRANSPORT_ETH);
}
static int dissect_1722_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
return dissect_1722_common(tvb, pinfo, tree, IEEE_1722_TRANSPORT_UDP);
}
/* Register the protocol with Wireshark */
void proto_register_1722(void)
{
static hf_register_info hf[] = {
{ &hf_1722_encap_seqnum,
{ "Encapsulation Sequence Number", "ieee1722.encapsulation_sequence_num",
FT_UINT32, BASE_HEX, NULL, 0x00,
"Sequence number incremented for each AVTPDU on a 5-tuple", HFILL }
},
{ &hf_1722_subtype,
{ "AVTP Subtype", "ieee1722.subtype",
FT_UINT8, BASE_HEX | BASE_RANGE_STRING, RVALS(subtype_range_rvals), 0x00, NULL, HFILL }
@ -860,10 +934,17 @@ void proto_register_1722(void)
}
};
static ei_register_info ei[] = {
{ &ei_1722_encap_seqnum_dup, { "ieee1722.encapsulation_sequence_num.dup", PI_SEQUENCE, PI_NOTE, "Duplicate encapsulation_sequence_num (retransmission?)", EXPFILL }},
{ &ei_1722_encap_seqnum_ooo, { "ieee1722.encapsulation_sequence_num.ooo", PI_SEQUENCE, PI_WARN, "Unexpected encapsulation_sequence_num (lost or out-of-order?)", EXPFILL }},
};
static gint *ett[] = {
&ett_1722
};
expert_module_t *expert_1722;
/* Register the protocol name and description */
proto_1722 = proto_register_protocol("IEEE 1722 Audio Video Transport Protocol (AVTP)", "IEEE1722", "ieee1722");
@ -871,18 +952,22 @@ void proto_register_1722(void)
proto_register_field_array(proto_1722, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* Sub-dissector for 1772.1, 1722 AAF, 1722 CRF, 1722 61883, 1722 CVF */
expert_1722 = expert_register_protocol(proto_1722);
expert_register_field_array(expert_1722, ei, array_length(ei));
/* Sub-dissector for 1722.1, 1722 AAF, 1722 CRF, 1722 61883, 1722 CVF */
avb_dissector_table = register_dissector_table("ieee1722.subtype",
"IEEE1722 AVTP Subtype", proto_1722, FT_UINT8, BASE_HEX);
}
void proto_reg_handoff_1722(void)
{
dissector_handle_t avtp_handle;
dissector_handle_t avtp_handle_eth, avtp_handle_udp;
avtp_handle = create_dissector_handle(dissect_1722, proto_1722);
dissector_add_uint("ethertype", ETHERTYPE_AVTP, avtp_handle);
dissector_add_uint("udp.port", UDP_PORT_IEEE_1722, avtp_handle);
avtp_handle_eth = create_dissector_handle(dissect_1722_eth, proto_1722);
avtp_handle_udp = create_dissector_handle(dissect_1722_udp, proto_1722);
dissector_add_uint("ethertype", ETHERTYPE_AVTP, avtp_handle_eth);
dissector_add_uint_with_preference("udp.port", UDP_PORT_IEEE_1722, avtp_handle_udp);
}
/**************************************************************************************************/