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DECT-MITEL-ETH: Add IP encapsulated behaviour 

The ETH protocol has an two byte field that is only used when
transported over RAW Ethernet and a length indicator in that case.
Those two fields are not present if the ETH protocol is encapsulated
in the OMM/RFP communication protocol.
To make this dissector also useable when used after dissecting
DECT-MITEL-RFP distinguishing between both packet structures has
been included.
This commit is contained in:
Bernhard Dick 2022-11-16 14:14:21 +01:00 committed by Martin Mathieson
parent a31c5923e1
commit d4a4d8ebc0
1 changed files with 52 additions and 28 deletions
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80
epan/dissectors/packet-dect-mitel-eth.c
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@ -18,6 +18,7 @@
#include <epan/packet.h> #include <epan/packet.h>
#include <epan/packet_info.h> #include <epan/packet_info.h>
#include <epan/value_string.h> #include <epan/value_string.h>
#include <tvbuff.h>
void proto_register_dect_mitel_eth(void); void proto_register_dect_mitel_eth(void);
void proto_reg_handoff_dect_mitelrfp(void); void proto_reg_handoff_dect_mitelrfp(void);
@ -108,51 +109,69 @@ static const value_string dect_mitel_eth_subfield_val[] = {
{ 0, NULL } { 0, NULL }
}; };
static int dissect_dect_mitel_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) static int dissect_dect_mitel_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{ {
guint16 mitel_eth_len, payload_len; guint16 mitel_eth_len, payload_len;
guint8 prim_type, mcei; guint8 prim_type, mcei;
int offset = 0; int offset = 0;
gboolean ip_encapsulated;
tvbuff_t *payload_tvb = NULL; tvbuff_t *payload_tvb = NULL;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "MI-DECToE"); col_set_str(pinfo->cinfo, COL_PROTOCOL, "MI-DECToE");
col_clear(pinfo->cinfo, COL_INFO); col_clear(pinfo->cinfo, COL_INFO);
mitel_eth_len = tvb_get_guint16(tvb, offset, 2); /*
proto_tree_add_item(tree, hf_dect_mitel_eth_len, tvb, offset, 2, ENC_BIG_ENDIAN); * When the protocol is used within the internal Ethernet channel in the RFP there is a two byte
offset += 2; * field with not yet really known content and a two byte length field. This is not in place / consumed
* by the upper layer dissector if this protocol is used in OMM<>RFP communication. So the data parameter
* is used to get information from the dect-mitel-rfp dissector whether it was IP encapsulated or not.
*/
if(data) {
ip_encapsulated = *( ( gboolean* )data );
} else {
ip_encapsulated = false;
}
if(!ip_encapsulated) {
mitel_eth_len = tvb_get_guint16(tvb, offset, 2);
proto_tree_add_item(tree, hf_dect_mitel_eth_len, tvb, offset, 2, ENC_BIG_ENDIAN);
if (mitel_eth_len < 3)
return tvb_captured_length(tvb);
offset += 4;
}
if (mitel_eth_len < 3) offset++;
return tvb_captured_length(tvb); prim_type = tvb_get_guint8(tvb, offset);
proto_tree_add_item(tree, hf_dect_mitel_eth_prim_type, tvb, offset, 1, ENC_NA);
prim_type = tvb_get_guint8(tvb, offset+3);
proto_tree_add_item(tree, hf_dect_mitel_eth_prim_type, tvb, offset+3, 1, ENC_NA);
col_append_fstr(pinfo->cinfo, COL_INFO, "%s ", col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
val_to_str(prim_type, dect_mitel_eth_prim_coding_val, "Unknown 0x%02x")); val_to_str(prim_type, dect_mitel_eth_prim_coding_val, "Unknown 0x%02x"));
offset++;
switch (prim_type) { switch (prim_type) {
case DECT_MITEL_ETH_MAC_PAGE_REQ: case DECT_MITEL_ETH_MAC_PAGE_REQ:
pinfo->p2p_dir = P2P_DIR_SENT; pinfo->p2p_dir = P2P_DIR_SENT;
payload_len = tvb_get_guint8(tvb, offset+4); payload_len = tvb_get_guint8(tvb, offset);
payload_tvb = tvb_new_subset_length(tvb, offset+5, payload_len); offset++;
payload_tvb = tvb_new_subset_length(tvb, offset, payload_len);
break; break;
case DECT_MITEL_ETH_MAC_CON_IND: case DECT_MITEL_ETH_MAC_CON_IND:
pinfo->p2p_dir = P2P_DIR_RECV; pinfo->p2p_dir = P2P_DIR_RECV;
mcei = tvb_get_guint8(tvb, offset+4); mcei = tvb_get_guint8(tvb, offset);
conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei); conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei);
col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei); col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei);
proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset+4, 1, ENC_NA); proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset, 1, ENC_NA);
proto_tree_add_item(tree, hf_dect_mitel_eth_pmid, tvb, offset+6, 2, ENC_BIG_ENDIAN); offset += 2;
proto_tree_add_item(tree, hf_dect_mitel_eth_pmid, tvb, offset, 2, ENC_BIG_ENDIAN);
break; break;
case DECT_MITEL_ETH_MAC_INFO_IND: case DECT_MITEL_ETH_MAC_INFO_IND:
pinfo->p2p_dir = P2P_DIR_RECV; pinfo->p2p_dir = P2P_DIR_RECV;
mcei = tvb_get_guint8(tvb, offset+4); mcei = tvb_get_guint8(tvb, offset);
conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei); conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei);
col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei); col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei);
proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset+4, 1, ENC_NA); proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset, 1, ENC_NA);
/* from offset 9 onwards, there's a null-terminated string */ /* from offset 9 onwards, there's a null-terminated string */
proto_tree_add_item(tree, hf_dect_mitel_eth_info_string, tvb, offset+9, offset += 5;
proto_tree_add_item(tree, hf_dect_mitel_eth_info_string, tvb, offset,
tvb_captured_length_remaining(tvb, offset+9), ENC_ASCII|ENC_NA); tvb_captured_length_remaining(tvb, offset+9), ENC_ASCII|ENC_NA);
break; break;
case DECT_MITEL_ETH_MAC_DIS_REQ: case DECT_MITEL_ETH_MAC_DIS_REQ:
@ -162,18 +181,19 @@ static int dissect_dect_mitel_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree
} else { } else {
pinfo->p2p_dir = P2P_DIR_RECV; pinfo->p2p_dir = P2P_DIR_RECV;
} }
mcei = tvb_get_guint8(tvb, offset+4); mcei = tvb_get_guint8(tvb, offset);
conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei); conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei);
col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei); col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei);
proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset+4, 1, ENC_NA); proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset, 1, ENC_NA);
break; break;
case DECT_MITEL_ETH_LC_DTR_IND: case DECT_MITEL_ETH_LC_DTR_IND:
pinfo->p2p_dir = P2P_DIR_RECV; pinfo->p2p_dir = P2P_DIR_RECV;
mcei = tvb_get_guint8(tvb, offset+4); mcei = tvb_get_guint8(tvb, offset);
conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei); conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei);
col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei); col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei);
proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset+4, 1, ENC_NA); proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset, 1, ENC_NA);
proto_tree_add_item(tree, hf_dect_mitel_eth_subfield, tvb, offset+5, 1, ENC_NA); offset++;
proto_tree_add_item(tree, hf_dect_mitel_eth_subfield, tvb, offset, 1, ENC_NA);
break; break;
case DECT_MITEL_ETH_LC_DATA_REQ: case DECT_MITEL_ETH_LC_DATA_REQ:
case DECT_MITEL_ETH_LC_DATA_IND: case DECT_MITEL_ETH_LC_DATA_IND:
@ -182,14 +202,16 @@ static int dissect_dect_mitel_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree
} else { } else {
pinfo->p2p_dir = P2P_DIR_RECV; pinfo->p2p_dir = P2P_DIR_RECV;
} }
mcei = tvb_get_guint8(tvb, offset+4); mcei = tvb_get_guint8(tvb, offset);
conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei); conversation_set_elements_by_id(pinfo, CONVERSATION_NONE, mcei);
col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei); col_append_fstr(pinfo->cinfo, COL_INFO, "MCEI=%02x ", mcei);
proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset+4, 1, ENC_NA); proto_tree_add_item(tree, hf_dect_mitel_eth_mcei, tvb, offset, 1, ENC_NA);
proto_tree_add_item(tree, hf_dect_mitel_eth_subfield, tvb, offset+5, 1, ENC_NA); offset++;
payload_len = tvb_get_guint8(tvb, offset+6); proto_tree_add_item(tree, hf_dect_mitel_eth_subfield, tvb, offset, 1, ENC_NA);
payload_len = tvb_get_guint8(tvb, offset+6); offset++;
payload_tvb = tvb_new_subset_length(tvb, offset+7, payload_len); payload_len = tvb_get_guint8(tvb, offset);
offset++;
payload_tvb = tvb_new_subset_length(tvb, offset, payload_len);
if (payload_tvb) if (payload_tvb)
call_dissector(dlc_handle, payload_tvb, pinfo, tree); call_dissector(dlc_handle, payload_tvb, pinfo, tree);
payload_tvb = NULL; payload_tvb = NULL;
@ -250,6 +272,8 @@ void proto_register_dect_mitelrfp(void)
proto_register_subtree_array(ett, array_length(ett)); proto_register_subtree_array(ett, array_length(ett));
proto_register_field_array(proto_dect_mitel_eth, hf, array_length(hf)); proto_register_field_array(proto_dect_mitel_eth, hf, array_length(hf));
register_dissector("dect_mitel_eth", dissect_dect_mitel_eth, proto_dect_mitel_eth);
} }
void proto_reg_handoff_dect_mitel_eth(void) void proto_reg_handoff_dect_mitel_eth(void)