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Remember Msg3 bytes and compare with Msg4 Contention Resolution bodies.

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svn path=/trunk/; revision=29258
This commit is contained in:
Martin Mathieson 2009-08-01 09:52:12 +00:00
parent f846e15d40
commit ed930bece3
1 changed files with 213 additions and 8 deletions
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221
epan/dissectors/packet-mac-lte.c
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@ -41,7 +41,6 @@
/* TODO:
- TDD mode?
- compare Msg3 with contention resolution body
- add a preference so that padding can be verified against an expected pattern?
*/
@ -119,7 +118,10 @@ static int hf_mac_lte_control_bsr_buffer_size_4 = -1;
static int hf_mac_lte_control_crnti = -1;
static int hf_mac_lte_control_timing_advance = -1;
static int hf_mac_lte_control_timing_advance_reserved = -1;
static int hf_mac_lte_control_ue_contention_resolution = -1;
static int hf_mac_lte_control_ue_contention_resolution_identity = -1;
static int hf_mac_lte_control_ue_contention_resolution_msg3 = -1;
static int hf_mac_lte_control_ue_contention_resolution_msg3_matched = -1;
static int hf_mac_lte_control_power_headroom_reserved = -1;
static int hf_mac_lte_control_power_headroom = -1;
static int hf_mac_lte_control_padding = -1;
@ -138,6 +140,7 @@ static int ett_mac_lte_rar_ul_grant = -1;
static int ett_mac_lte_bsr = -1;
static int ett_mac_lte_bch = -1;
static int ett_mac_lte_pch = -1;
static int ett_mac_lte_contention_resolution = -1;
@ -375,6 +378,69 @@ static gboolean global_mac_lte_decode_rar_ul_grant = TRUE;
/* Whether should attempt to dissect frames failing CRC check */
static gboolean global_mac_lte_dissect_crc_failures = FALSE;
/***************************************************************/
/* Keeping track of Msg3 bodies so they can be compared with */
/* Contention Resolution bodies. */
typedef struct Msg3Data {
guint8 data[6];
guint32 framenum;
} Msg3Data;
/* This table stores (RNTI -> Msg3Data*). Will be populated when
Msg3 frames are first read. */
static GHashTable *mac_lte_msg3_hash = NULL;
/* Hash table functions for mac_lte_msg3_hash. Hash is just the (RNTI) key */
static gint mac_lte_msg3_hash_equal(gconstpointer v, gconstpointer v2)
{
return (v == v2);
}
static guint mac_lte_msg3_hash_func(gconstpointer v)
{
return GPOINTER_TO_UINT(v);
}
typedef enum ContentionResolutionStatus {
NoMsg3,
Msg3Match,
Msg3NoMatch
} ContentionResolutionStatus;
typedef struct ContentionResolutionResult {
ContentionResolutionStatus status;
guint msg3FrameNum;
} ContentionResolutionResult;
/* This table stores (CRFrameNum -> CRResult). It is assigned during the first
pass and used thereafter */
static GHashTable *mac_lte_cr_result_hash = NULL;
/* Hash table functions for mac_lte_cr_result_hash. Hash is just the (framenum) key */
static gint mac_lte_cr_result_hash_equal(gconstpointer v, gconstpointer v2)
{
return (v == v2);
}
static guint mac_lte_cr_result_hash_func(gconstpointer v)
{
return GPOINTER_TO_UINT(v);
}
/**************************************************************************/
/* Forward declarations */
void proto_reg_handoff_mac_lte(void);
void dissect_mac_lte(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
@ -1132,6 +1198,26 @@ static void dissect_ulsch_or_dlsch(tvbuff_t *tvb, packet_info *pinfo, proto_tree
"Unknown"),
data_length);
/* Look for Msg3 data so that it may be compared with later
Contention Resolution body */
if ((lcids[n] == 0) && (direction == DIRECTION_UPLINK) && (data_length == 6)) {
if (!pinfo->fd->flags.visited) {
guint key = p_mac_lte_info->rnti;
Msg3Data *data = g_hash_table_lookup(mac_lte_msg3_hash, GUINT_TO_POINTER(key));
/* Look for previous entry for this UE */
if (data == NULL) {
/* Allocate space for data and add to table */
data = se_alloc(sizeof(Msg3Data));
g_hash_table_insert(mac_lte_msg3_hash, GUINT_TO_POINTER(key), data);
}
/* Fill in data details */
data->framenum = pinfo->fd->num;
memcpy(&data->data, tvb_get_ptr(tvb, offset, data_length), data_length);
}
}
/* CCCH frames can be dissected directly by LTE RRC... */
if ((lcids[n] == 0) && global_mac_lte_attempt_rrc_decode) {
tvbuff_t *rrc_tvb = tvb_new_subset(tvb, offset, data_length, data_length);
@ -1171,9 +1257,86 @@ static void dissect_ulsch_or_dlsch(tvbuff_t *tvb, packet_info *pinfo, proto_tree
/* DL-SCH Control PDUs */
switch (lcids[n]) {
case UE_CONTENTION_RESOLUTION_IDENTITY_LCID:
proto_tree_add_item(tree, hf_mac_lte_control_ue_contention_resolution_identity,
tvb, offset, 6, FALSE);
offset += 6;
{
proto_item *cr_ti;
proto_tree *cr_tree;
proto_item *ti;
ContentionResolutionResult *crResult;
/* Create CR root */
cr_ti = proto_tree_add_string_format(tree,
hf_mac_lte_control_ue_contention_resolution,
tvb, offset, 6,
"",
"Contention Resolution");
cr_tree = proto_item_add_subtree(cr_ti, ett_mac_lte_contention_resolution);
proto_tree_add_item(cr_tree, hf_mac_lte_control_ue_contention_resolution_identity,
tvb, offset, 6, FALSE);
/* Get pointer to result struct for this frame */
crResult = g_hash_table_lookup(mac_lte_cr_result_hash, GUINT_TO_POINTER(pinfo->fd->num));
if (crResult == NULL) {
/* Need to set result by looking for and comparing with Msg3 */
Msg3Data *msg3Data;
guint msg3Key = p_mac_lte_info->rnti;
/* Allocate result and add it to the table */
crResult = se_alloc(sizeof(ContentionResolutionResult));
g_hash_table_insert(mac_lte_cr_result_hash, GUINT_TO_POINTER(pinfo->fd->num), crResult);
/* Look for Msg3 */
msg3Data = g_hash_table_lookup(mac_lte_msg3_hash, GUINT_TO_POINTER(msg3Key));
/* Compare CCCH bytes */
if (msg3Data != NULL) {
crResult->msg3FrameNum = msg3Data->framenum;
if (memcmp(&msg3Data->data, tvb_get_ptr(tvb, offset, 6), 6) == 0) {
crResult->status = Msg3Match;
}
else {
crResult->status = Msg3NoMatch;
}
}
else {
crResult->status = NoMsg3;
}
}
/* Now show CR result in tree */
switch (crResult->status) {
case NoMsg3:
proto_item_append_text(cr_ti, " (no corresponding Msg3 found!)");
break;
case Msg3Match:
ti = proto_tree_add_uint(cr_tree, hf_mac_lte_control_ue_contention_resolution_msg3,
tvb, 0, 0, crResult->msg3FrameNum);
PROTO_ITEM_SET_GENERATED(ti);
ti = proto_tree_add_boolean(cr_tree, hf_mac_lte_control_ue_contention_resolution_msg3_matched,
tvb, 0, 0, TRUE);
PROTO_ITEM_SET_GENERATED(ti);
proto_item_append_text(cr_ti, " (matches Msg3 from frame %u)", crResult->msg3FrameNum);
break;
case Msg3NoMatch:
ti = proto_tree_add_uint(cr_tree, hf_mac_lte_control_ue_contention_resolution_msg3,
tvb, 0, 0, crResult->msg3FrameNum);
PROTO_ITEM_SET_GENERATED(ti);
ti = proto_tree_add_boolean(cr_tree, hf_mac_lte_control_ue_contention_resolution_msg3_matched,
tvb, 0, 0, FALSE);
expert_add_info_format(pinfo, ti, PI_SEQUENCE, PI_WARN,
"CR body in Msg4 doesn't match Msg3 CCCH in frame %u",
crResult->msg3FrameNum);
PROTO_ITEM_SET_GENERATED(ti);
proto_item_append_text(cr_ti, " (doesn't match Msg3 from frame %u)", crResult->msg3FrameNum);
break;
};
offset += 6;
}
break;
case TIMING_ADVANCE_LCID:
{
@ -1524,6 +1687,26 @@ void dissect_mac_lte(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
}
/* Initializes the hash table and the mem_chunk area each time a new
* file is loaded or re-loaded in wireshark */
static void
mac_lte_init_protocol(void)
{
/* Destroy any existing tables. */
if (mac_lte_msg3_hash) {
g_hash_table_destroy(mac_lte_msg3_hash);
}
if (mac_lte_cr_result_hash) {
g_hash_table_destroy(mac_lte_cr_result_hash);
}
/* Now create them over */
mac_lte_msg3_hash = g_hash_table_new(mac_lte_msg3_hash_func, mac_lte_msg3_hash_equal);
mac_lte_cr_result_hash = g_hash_table_new(mac_lte_cr_result_hash_func, mac_lte_cr_result_hash_equal);
}
void proto_register_mac_lte(void)
{
static hf_register_info hf[] =
@ -1888,12 +2071,31 @@ void proto_register_mac_lte(void)
"Reserved bits", HFILL
}
},
{ &hf_mac_lte_control_ue_contention_resolution_identity,
{ "UE Contention Resolution Identity",
"mac-lte.control.ue-contention-resolution-identity", FT_BYTES, BASE_NONE, 0, 0x0,
{ &hf_mac_lte_control_ue_contention_resolution,
{ "UE Contention Resolution",
"mac-lte.control.ue-contention-resolution", FT_STRING, BASE_NONE, 0, 0x0,
NULL, HFILL
}
},
{ &hf_mac_lte_control_ue_contention_resolution_identity,
{ "UE Contention Resolution Identity",
"mac-lte.control.ue-contention-resolution.identity", FT_BYTES, BASE_NONE, 0, 0x0,
NULL, HFILL
}
},
{ &hf_mac_lte_control_ue_contention_resolution_msg3,
{ "Msg3",
"mac-lte.control.ue-contention-resolution.msg3", FT_FRAMENUM, BASE_NONE, 0, 0x0,
NULL, HFILL
}
},
{ &hf_mac_lte_control_ue_contention_resolution_msg3_matched,
{ "UE Contention Resolution Matches Msg3",
"mac-lte.control.ue-contention-resolution.matches-msg3", FT_BOOLEAN, BASE_NONE, 0, 0x0,
NULL, HFILL
}
},
{ &hf_mac_lte_control_power_headroom_reserved,
{ "Reserved",
"mac-lte.control.power-headroom.reserved", FT_UINT8, BASE_DEC, 0, 0xc0,
@ -1927,7 +2129,8 @@ void proto_register_mac_lte(void)
&ett_mac_lte_sch_subheader,
&ett_mac_lte_bch,
&ett_mac_lte_bsr,
&ett_mac_lte_pch
&ett_mac_lte_pch,
&ett_mac_lte_contention_resolution
};
module_t *mac_lte_module;
@ -1979,6 +2182,8 @@ void proto_register_mac_lte(void)
"When enabled, use heuristic dissector to find MAC-LTE frames sent with "
"UDP framing",
&global_mac_lte_heur);
register_init_routine(&mac_lte_init_protocol);
}
void