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packet-dlm3: dissect pdus for tcp case 

Currently there can be multiple dlm messages in one tcp segment and in
some cases dlm message can be overlapped between two segments. The main
fix would be that we can now dissect multiple dlm messages if they
appear in one tcp segment. It's still own as one message in the "packet
flow" but in tree view it will be displayed as multiple messages which
are not visible.

For sctp the problem still exists, although there can't be overlapped messages.
This commit is contained in:
Alexander Aring 2021-06-24 15:46:56 -04:00 committed by Wireshark GitLab Utility
parent 69fb2a17e4
commit 456c74cb1f
1 changed files with 26 additions and 2 deletions
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28
epan/dissectors/packet-dlm3.c
View File

@ -36,7 +36,7 @@
#include <epan/packet.h>
#include <epan/prefs.h>
#include "packet-tcp.h"
#define TCP_PORT_DLM3 21064 /* Not IANA registered */
#define SCTP_PORT_DLM3 TCP_PORT_DLM3
@ -155,6 +155,8 @@
#define DLM3_RESNAME_MAXLEN 64
#define DLM_HEADER_LEN (4 + 4 + 4 + 2 + 1 + 1)
/* Forward declaration we need below */
void proto_register_dlm3(void);
void proto_reg_handoff_dlm3(void);
@ -958,6 +960,28 @@ dissect_dlm3(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *d
return tvb_captured_length(tvb);
}
/* This method dissects fully reassembled messages */
static int
dissect_dlm3_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_)
{
dissect_dlm3(tvb, pinfo, tree, data);
return tvb_captured_length(tvb);
}
/* determine PDU length of protocol foo */
static guint
get_dlm3_message_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
{
return tvb_get_letohs(tvb, offset + DLM_HEADER_LEN - 2 - 1 - 1);
}
static int
dissect_tcp_dlm3(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
tcp_dissect_pdus(tvb, pinfo, tree, TRUE, DLM_HEADER_LEN - 1 - 1,
get_dlm3_message_len, dissect_dlm3_message, data);
return tvb_captured_length(tvb);
}
/* Register the protocol with Wireshark */
@ -1559,7 +1583,7 @@ proto_reg_handoff_dlm3(void)
if (!dissector_registered) {
dlm3_sctp_handle = create_dissector_handle(dissect_dlm3, proto_dlm3);
dlm3_tcp_handle = create_dissector_handle(dissect_dlm3, proto_dlm3);
dlm3_tcp_handle = create_dissector_handle(dissect_tcp_dlm3, proto_dlm3);
dissector_add_uint_with_preference("tcp.port", TCP_PORT_DLM3, dlm3_tcp_handle);
dissector_registered = TRUE;
} else {