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EPL: Fix segmented transfer complete detection 

In case of a segmented SDO transfer, the transfer complete response can
 contain additional data that should not be evaluated by the dissector.

Change-Id: I7016eb88b93aac8c318e703fe60a90c3adbf9eeb
Reviewed-on: https://code.wireshark.org/review/14692
Petri-Dish: Roland Knall <rknall@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Roland Knall <rknall@gmail.com>
This commit is contained in:
Christoph Schlosser 2016-03-21 09:27:03 +01:00 committed by Roland Knall
parent 93ac8364f1
commit 070ea6f587
1 changed files with 96 additions and 53 deletions
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149
epan/dissectors/packet-epl.c
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@ -446,6 +446,8 @@ static struct _epl_segmentation{
static epl_sdo_reassembly epl_asnd_sdo_reassembly_write;
static epl_sdo_reassembly epl_asnd_sdo_reassembly_read;
static gboolean first_read = TRUE;
static gboolean first_write = TRUE;
/* Priority values for EPL message type "ASnd", "", "", field PR */
#define EPL_PR_GENERICREQUEST 0x03
@ -1650,6 +1652,10 @@ static void
cleanup_dissector(void)
{
reassembly_table_destroy(&epl_reassembly_table);
count = 0;
ct = 0;
first_read = TRUE;
first_write = TRUE;
}
/* preference whether or not display the SoC flags in info column */
@ -2820,14 +2826,15 @@ dissect_epl_sdo_command(proto_tree *epl_tree, tvbuff_t *tvb, packet_info *pinfo,
gboolean response, abort_flag;
guint32 abort_code = 0;
guint32 fragmentId = 0, remlength = 0;
guint16 segment_size;
guint16 segment_size = 0;
proto_tree *sdo_cmd_tree = NULL;
proto_tree *payload = NULL;
proto_item *item;
fragment_head *frag_msg = NULL;
guint8 sendCon = 0;
offset += 1;
sendCon = tvb_get_guint8(tvb, 5) & EPL_ASND_SDO_SEQ_SEND_CON_ERROR_VALID_ACK_REQ;
command_id = tvb_get_guint8(tvb, offset + 2);
abort_flag = tvb_get_guint8(tvb, offset + 1) & EPL_ASND_SDO_CMD_ABORT_FILTER;
@ -2840,6 +2847,7 @@ dissect_epl_sdo_command(proto_tree *epl_tree, tvbuff_t *tvb, packet_info *pinfo,
transaction_id = tvb_get_guint8(tvb, offset);
response = tvb_get_guint8(tvb, offset + 1) & EPL_ASND_SDO_CMD_RESPONSE_FILTER;
segmented = (tvb_get_guint8(tvb, offset + 1) & EPL_ASND_SDO_CMD_SEGMENTATION_FILTER) >> 4;
segment_size = tvb_get_letohs(tvb, offset + 3);
col_append_fstr(pinfo->cinfo, COL_INFO, "Cmd:%s,TID=%02d ",
@ -2852,14 +2860,16 @@ dissect_epl_sdo_command(proto_tree *epl_tree, tvbuff_t *tvb, packet_info *pinfo,
proto_tree_add_item(sdo_cmd_tree, hf_epl_asnd_sdo_cmd_abort, tvb, offset, 1, ENC_LITTLE_ENDIAN);
proto_tree_add_item(sdo_cmd_tree, hf_epl_asnd_sdo_cmd_segmentation, tvb, offset, 1, ENC_LITTLE_ENDIAN);
offset += 1;
proto_tree_add_item(sdo_cmd_tree, hf_epl_asnd_sdo_cmd_command_id, tvb, offset, 1, ENC_LITTLE_ENDIAN);
offset += 1;
proto_tree_add_item(sdo_cmd_tree, hf_epl_asnd_sdo_cmd_segment_size, tvb, offset, 2, ENC_LITTLE_ENDIAN);
offset += 4;
if (segment_size != 0)
{
offset += 1;
proto_tree_add_item(sdo_cmd_tree, hf_epl_asnd_sdo_cmd_command_id, tvb, offset, 1, ENC_LITTLE_ENDIAN);
offset += 1;
proto_tree_add_item(sdo_cmd_tree, hf_epl_asnd_sdo_cmd_segment_size, tvb, offset, 2, ENC_LITTLE_ENDIAN);
offset += 4;
}
/* adjust size of packet */
tvb_set_reported_length(tvb, offset + segment_size);
@ -2867,12 +2877,15 @@ dissect_epl_sdo_command(proto_tree *epl_tree, tvbuff_t *tvb, packet_info *pinfo,
{
if((command_id == EPL_ASND_SDO_COMMAND_WRITE_BY_INDEX) || (command_id == EPL_ASND_SDO_COMMAND_READ_BY_INDEX))
{
/* if download => reset counter */
if(command_id == EPL_ASND_SDO_COMMAND_WRITE_BY_INDEX)
ct = 0x00;
/* if upload => reset counter */
else if(command_id == EPL_ASND_SDO_COMMAND_READ_BY_INDEX)
count = 0x00;
if (sendCon != EPL_ASND_SDO_SEQ_SEND_CON_ERROR_VALID_ACK_REQ)
{
/* if download => reset counter */
if(command_id == EPL_ASND_SDO_COMMAND_WRITE_BY_INDEX)
ct = 0x00;
/* if upload => reset counter */
else if(command_id == EPL_ASND_SDO_COMMAND_READ_BY_INDEX)
count = 0x00;
}
/* payload length */
payload_length = tvb_reported_length_remaining(tvb, offset);
/* create a key for reassembly => first 16 bit are src-address and
@ -2880,20 +2893,21 @@ dissect_epl_sdo_command(proto_tree *epl_tree, tvbuff_t *tvb, packet_info *pinfo,
fragmentId = (guint32)((((guint32)epl_segmentation.src)<<16)+epl_segmentation.dest);
/* set fragmented flag */
pinfo->fragmented = TRUE;
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragmentId, NULL, 0, payload_length, TRUE );
fragment_add_seq_offset ( &epl_reassembly_table, pinfo, fragmentId, NULL, 0 );
if (command_id == EPL_ASND_SDO_COMMAND_WRITE_BY_INDEX)
{
first_write = FALSE;
}
else
{
first_read = FALSE;
}
/* if Segmentation = Initiate then print DataSize */
proto_tree_add_item(sdo_cmd_tree, hf_epl_asnd_sdo_cmd_data_size, tvb, offset, 4, ENC_LITTLE_ENDIAN);
segmented = TRUE;
if(frag_msg != NULL)
{
item = proto_tree_add_uint_format(sdo_cmd_tree, hf_epl_asnd_sdo_cmd_reassembled, tvb, offset ,payload_length, 0,
"Reassembled: %d bytes total (%d bytes in this frame)",frag_msg->len,payload_length);
payload = proto_item_add_subtree(item, ett_epl_asnd_sdo_data_reassembled);
process_reassembled_data(tvb, 0, pinfo, "Reassembled Message", frag_msg, &epl_frag_items, NULL, payload );
}
offset += 4;
}
else
@ -2965,7 +2979,7 @@ dissect_epl_sdo_command(proto_tree *epl_tree, tvbuff_t *tvb, packet_info *pinfo,
gint
dissect_epl_sdo_command_write_by_index(proto_tree *epl_tree, tvbuff_t *tvb, packet_info *pinfo, gint offset, guint8 segmented, gboolean response, guint16 segment_size)
{
gint size, payload_length;
gint size, payload_length = 0;
guint16 idx = 0x00, nosub = 0x00, sod_index = 0x00, error = 0xFF, entries = 0x00, sub_val = 0x00;
guint8 subindex = 0x00;
guint32 fragmentId = 0;
@ -3091,6 +3105,7 @@ dissect_epl_sdo_command_write_by_index(proto_tree *epl_tree, tvbuff_t *tvb, pack
fragmentId = (guint32)((((guint32)epl_segmentation.src)<<16)+epl_segmentation.dest);
/* set the fragmented flag */
pinfo->fragmented = TRUE;
/* get payloade size */
payload_length = tvb_reported_length_remaining(tvb, offset);
/* if the frame is the last frame */
@ -3109,14 +3124,34 @@ dissect_epl_sdo_command_write_by_index(proto_tree *epl_tree, tvbuff_t *tvb, pack
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragmentId, NULL, ct, payload_length, end_segment ? FALSE : TRUE );
}
else if(epl_asnd_sdo_reassembly_write.frame[epl_segmentation.recv][epl_segmentation.send] == 0x00)
else
{
/* save the current frame and increase counter */
epl_asnd_sdo_reassembly_write.frame[epl_segmentation.recv][epl_segmentation.send] = frame;
ct += 1;
/* add the frame to reassembly_table */
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragmentId, NULL, ct, payload_length, end_segment ? FALSE : TRUE );
if(epl_asnd_sdo_reassembly_write.frame[epl_segmentation.recv][epl_segmentation.send] == 0x00)
{
/* save the current frame and increase counter */
epl_asnd_sdo_reassembly_write.frame[epl_segmentation.recv][epl_segmentation.send] = frame;
ct += 1;
/* add the frame to reassembly_table */
if (first_write)
{
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragmentId, NULL, 0, payload_length, end_segment ? FALSE : TRUE );
fragment_add_seq_offset(&epl_reassembly_table, pinfo, fragmentId, NULL, ct);
first_write = FALSE;
}
else
{
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragmentId, NULL, ct, payload_length, end_segment ? FALSE : TRUE );
}
}
else
{
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragmentId, NULL, 0, payload_length, end_segment ? FALSE : TRUE);
epl_asnd_sdo_reassembly_write.frame[epl_segmentation.recv][epl_segmentation.send] = frame;
}
}
/* if the reassembly_table is not Null and the frame stored is the same as the current frame */
@ -3133,8 +3168,6 @@ dissect_epl_sdo_command_write_by_index(proto_tree *epl_tree, tvbuff_t *tvb, pack
proto_tree_add_uint_format_value(payload_tree, hf_epl_asnd_sdo_cmd_reassembled, tvb, 0, 0,
payload_length, "%d bytes (over all fragments)", frag_msg->len);
col_append_str(pinfo->cinfo, COL_INFO, " (Message Reassembled)" );
/* reset memory */
memset(&epl_asnd_sdo_reassembly_write,0,sizeof(epl_sdo_reassembly));
}
else
{
@ -3144,9 +3177,10 @@ dissect_epl_sdo_command_write_by_index(proto_tree *epl_tree, tvbuff_t *tvb, pack
/* add reassemble field => Reassembled in: */
process_reassembled_data(tvb, 0, pinfo, "Reassembled Message", frag_msg, &epl_frag_items, NULL, payload_tree );
}
first_write = TRUE;
ct = 0;
}
}
size = tvb_reported_length_remaining(tvb, offset);
/* if the frame is a PDO Mapping and the subindex is bigger than 0x00 */
@ -3451,12 +3485,11 @@ dissect_epl_sdo_command_read_by_index(proto_tree *epl_tree, tvbuff_t *tvb, packe
segment_size, idx, subindex);
col_append_fstr(pinfo->cinfo, COL_INFO, " (%s", val_to_str_ext_const(((guint32) (idx << 16)), &sod_index_names, "User Defined"));
col_append_fstr(pinfo->cinfo, COL_INFO, "/%s)",val_to_str_ext_const((subindex|(idx<<16)), &sod_index_names, "User Defined"));
}
else
{
/* upload */
if(segmented > 0x01)
/* upload and no response */
if(segmented > 0x01 && segment_size != 0)
{
/* get the fragmentId */
fragmentId = (guint32)((((guint32)epl_segmentation.src)<<16)+epl_segmentation.dest);
@ -3468,28 +3501,34 @@ dissect_epl_sdo_command_read_by_index(proto_tree *epl_tree, tvbuff_t *tvb, packe
if(segmented == EPL_ASND_SDO_CMD_SEGMENTATION_TRANSFER_COMPLETE)
end_segment = TRUE;
/* if the send-sequence-number is at the end or the beginning of a sequence */
if(epl_segmentation.send == 0x3f || epl_segmentation.send <= 0x01 )
{
/* reset memory */
memset(&epl_asnd_sdo_reassembly_read,0,sizeof(epl_sdo_reassembly));
epl_asnd_sdo_reassembly_read.frame[epl_segmentation.recv][epl_segmentation.send] = frame;
count += 1;
}
else if(epl_asnd_sdo_reassembly_read.frame[epl_segmentation.recv][epl_segmentation.send] == 0x00)
if(epl_asnd_sdo_reassembly_read.frame[epl_segmentation.recv][epl_segmentation.send] == 0x00 ||
epl_asnd_sdo_reassembly_read.frame[epl_segmentation.recv][epl_segmentation.send] == frame)
{
if (epl_asnd_sdo_reassembly_read.frame[epl_segmentation.recv][epl_segmentation.send] == 0x00)
count += 1;
/* store the current frame and increase the counter */
epl_asnd_sdo_reassembly_read.frame[epl_segmentation.recv][epl_segmentation.send] = frame;
count += 1;
}
/* add the frame to reassembly_table */
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
/* add the frame to reassembly_table */
if (first_read)
{
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragmentId, NULL, 0, payload_length, end_segment ? FALSE : TRUE );
fragment_add_seq_offset(&epl_reassembly_table, pinfo, fragmentId, NULL, count);
first_read = FALSE;
}
else
{
frag_msg = fragment_add_seq_check(&epl_reassembly_table, tvb, offset, pinfo,
fragmentId, NULL, count, payload_length, end_segment ? FALSE : TRUE );
}
}
/* if the reassembly_table is not Null and the frame stored is the same as the current frame */
if(frag_msg != NULL && (epl_asnd_sdo_reassembly_read.frame[epl_segmentation.recv][epl_segmentation.send] == frame))
{
if(end_segment)
if(end_segment || payload_length > 0)
{
cmd_payload = proto_tree_add_uint_format(epl_tree, hf_epl_asnd_sdo_cmd_reassembled, tvb, offset, payload_length,0,
"Reassembled: %d bytes total (%d bytes in this frame)",frag_msg->len,payload_length);
@ -3498,9 +3537,10 @@ dissect_epl_sdo_command_read_by_index(proto_tree *epl_tree, tvbuff_t *tvb, packe
process_reassembled_data(tvb, 0, pinfo, "Reassembled Message", frag_msg, &epl_frag_items, NULL, payload_tree );
proto_tree_add_uint_format_value(payload_tree, hf_epl_asnd_sdo_cmd_reassembled, tvb, 0, 0,
payload_length, "%d bytes (over all fragments)", frag_msg->len);
col_append_str(pinfo->cinfo, COL_INFO, " (Message Reassembled)" );
if (frag_msg->reassembled_in == frame)
col_append_str(pinfo->cinfo, COL_INFO, " (Message Reassembled)" );
/* reset memory */
memset(&epl_asnd_sdo_reassembly_read,0,sizeof(epl_sdo_reassembly));
memset(&epl_asnd_sdo_reassembly_read.frame[epl_segmentation.recv], 0, sizeof(guint32) * EPL_MAX_SEQUENCE);
}
else
{
@ -3510,6 +3550,9 @@ dissect_epl_sdo_command_read_by_index(proto_tree *epl_tree, tvbuff_t *tvb, packe
/* add reassemble field => Reassembled in: */
process_reassembled_data(tvb, 0, pinfo, "Reassembled Message", frag_msg, &epl_frag_items, NULL, payload_tree );
}
first_read = TRUE;
count = 0;
}
}
/* response */