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mptcp: Correctly find mappings and reinjections 

- removed mptcp.duplicated_dsn in favor of mptcp.reinjection_of/mptcp.reinjected_in
reinjected_in lists the packets where the DSN was later reinjected in.
reinjection_of lists the packets in which this DSN was already transmitted.
- There was a bug where the max_edge property of the interval tree was not
correctly updated. Right now wireshark gives a dsn for every TCP frame (even
empty packets).
- Now displays mappings only for packets with data (seglen > 0).
- Renamed dsn_map to dsn2packet_map and mappings to ssn2dsn_mappings.
- precises the complexity of enabling certain MPTCP options so that the user
better understand their impact on processing speed.

Change-Id: I24adc3161021b7f6a084763a74dc580f1c1f2c2e
Reviewed-on: https://code.wireshark.org/review/28326
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Matthieu Coudron 2018-06-19 09:29:01 +09:00 committed by Anders Broman
parent c5ede2f8c5
commit dac91db65e
3 changed files with 87 additions and 73 deletions
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143
epan/dissectors/packet-tcp.c
View File

@ -285,7 +285,9 @@ static int hf_mptcp_analysis_subflows_stream_id = -1;
static int hf_mptcp_analysis_subflows = -1;
static int hf_mptcp_number_of_removed_addresses = -1;
static int hf_mptcp_related_mapping = -1;
static int hf_mptcp_duplicated_data = -1;
static int hf_mptcp_reinjection_of = -1;
static int hf_mptcp_reinjected_in = -1;
static int hf_tcp_option_fast_open_cookie_request = -1;
static int hf_tcp_option_fast_open_cookie = -1;
@ -1455,8 +1457,8 @@ mptcp_init_subflow(tcp_flow_t *flow)
DISSECTOR_ASSERT(flow->mptcp_subflow == 0);
flow->mptcp_subflow = sf;
sf->mappings = wmem_itree_new(wmem_file_scope());
sf->dsn_map = wmem_itree_new(wmem_file_scope());
sf->ssn2dsn_mappings = wmem_itree_new(wmem_file_scope());
sf->dsn2packet_map = wmem_itree_new(wmem_file_scope());
}
@ -2607,13 +2609,13 @@ guint64 rawdsn64low, guint64 rawdsn64high
mptcp_dsn2packet_mapping_t *packet = NULL;
proto_item *item = NULL;
results = wmem_itree_find_intervals(subflow->mappings,
results = wmem_itree_find_intervals(subflow->dsn2packet_map,
wmem_packet_scope(),
rawdsn64low,
rawdsn64high
);
for(packet_it=wmem_list_head(results);
for(packet_it = wmem_list_head(results);
packet_it != NULL;
packet_it = wmem_list_frame_next(packet_it))
{
@ -2621,43 +2623,18 @@ guint64 rawdsn64low, guint64 rawdsn64high
packet = (mptcp_dsn2packet_mapping_t *) wmem_list_frame_data(packet_it);
DISSECTOR_ASSERT(packet);
item = proto_tree_add_uint(tree, hf_mptcp_duplicated_data, tvb, 0, 0, packet->frame);
if(pinfo->num > packet->frame) {
item = proto_tree_add_uint(tree, hf_mptcp_reinjection_of, tvb, 0, 0, packet->frame);
}
else {
item = proto_tree_add_uint(tree, hf_mptcp_reinjected_in, tvb, 0, 0, packet->frame);
}
PROTO_ITEM_SET_GENERATED(item);
}
return packet;
}
/* Finds mappings that cover the sent data */
static mptcp_dss_mapping_t *
mptcp_add_matching_dss_on_subflow(packet_info *pinfo _U_, proto_tree *tree, tvbuff_t *tvb, struct mptcp_subflow *subflow,
guint32 relseq, guint32 seglen
)
{
wmem_list_t *results = NULL;
wmem_list_frame_t *dss_it = NULL;
mptcp_dss_mapping_t *mapping = NULL;
proto_item *item = NULL;
results = wmem_itree_find_intervals(subflow->mappings,
wmem_packet_scope(),
relseq,
(seglen) ? relseq + seglen - 1 : relseq
);
for(dss_it=wmem_list_head(results);
dss_it!= NULL;
dss_it= wmem_list_frame_next(dss_it))
{
mapping = (mptcp_dss_mapping_t *) wmem_list_frame_data(dss_it);
DISSECTOR_ASSERT(mapping);
item = proto_tree_add_uint(tree, hf_mptcp_related_mapping, tvb, 0, 0, mapping->frame);
PROTO_ITEM_SET_GENERATED(item);
}
return mapping;
}
/* Lookup mappings that describe the packet and then converts the tcp seq number
* into the MPTCP Data Sequence Number (DSN)
@ -2698,13 +2675,29 @@ mptcp_analysis_dsn_lookup(packet_info *pinfo , tvbuff_t *tvb,
rawdsn = tcpd->fwd->mptcp_subflow->meta->base_dsn;
convert = DSN_CONV_NONE;
}
/* if it's a non-syn packet without data (just used to convey TCP options)
* then there would be no mappings */
else if(relseq == 1 && tcph->th_seglen == 0) {
rawdsn = tcpd->fwd->mptcp_subflow->meta->base_dsn + 1;
convert = DSN_CONV_NONE;
}
else {
/* display packets that conveyed the mappings covering the data range */
mapping = mptcp_add_matching_dss_on_subflow(pinfo, parent_tree, tvb,
tcpd->fwd->mptcp_subflow, relseq,
(tcph->th_have_seglen) ? tcph->th_seglen : 0
);
if(mapping == NULL) {
wmem_list_frame_t *dss_it = NULL;
wmem_list_t *results = NULL;
guint32 ssn_low = relseq;
guint32 seglen = tcph->th_seglen;
results = wmem_itree_find_intervals(tcpd->fwd->mptcp_subflow->ssn2dsn_mappings,
wmem_packet_scope(),
ssn_low,
(seglen) ? ssn_low + seglen - 1 : ssn_low
);
dss_it = wmem_list_head(results); /* assume it's always ok */
if(dss_it) {
mapping = (mptcp_dss_mapping_t *) wmem_list_frame_data(dss_it);
}
if(dss_it == NULL || mapping == NULL) {
expert_add_info(pinfo, parent_tree, &ei_mptcp_mapping_missing);
return;
}
@ -2713,6 +2706,19 @@ mptcp_analysis_dsn_lookup(packet_info *pinfo , tvbuff_t *tvb,
}
DISSECTOR_ASSERT(mapping);
if(seglen) {
/* Finds mappings that cover the sent data and adds them to the dissection tree */
for(dss_it = wmem_list_head(results);
dss_it != NULL;
dss_it = wmem_list_frame_next(dss_it))
{
mapping = (mptcp_dss_mapping_t *) wmem_list_frame_data(dss_it);
DISSECTOR_ASSERT(mapping);
item = proto_tree_add_uint(parent_tree, hf_mptcp_related_mapping, tvb, 0, 0, mapping->frame);
PROTO_ITEM_SET_GENERATED(item);
}
}
convert = (mapping->extended_dsn) ? DSN_CONV_NONE : DSN_CONV_32_TO_64;
DISSECTOR_ASSERT(mptcp_map_relssn_to_rawdsn(mapping, relseq, &rawdsn));
@ -2732,39 +2738,40 @@ mptcp_analysis_dsn_lookup(packet_info *pinfo , tvbuff_t *tvb,
proto_item_append_text(item, " (Relative)");
}
/* register */
if (!PINFO_FD_VISITED(pinfo))
{
mptcp_dsn2packet_mapping_t *packet;
packet = wmem_new0(wmem_file_scope(), mptcp_dsn2packet_mapping_t);
packet->frame = pinfo->fd->num;
packet->subflow = tcpd;
/* register dsn->packet mapping */
if(mptcp_intersubflows_retransmission
&& !PINFO_FD_VISITED(pinfo)
&& tcph->th_seglen > 0
) {
mptcp_dsn2packet_mapping_t *packet = 0;
packet = wmem_new0(wmem_file_scope(), mptcp_dsn2packet_mapping_t);
packet->frame = pinfo->fd->num;
packet->subflow = tcpd;
/* tcph->th_mptcp->mh_rawdsn64 */
if (tcph->th_have_seglen) {
wmem_itree_insert(tcpd->fwd->mptcp_subflow->dsn_map,
wmem_itree_insert(tcpd->fwd->mptcp_subflow->dsn2packet_map,
tcph->th_mptcp->mh_rawdsn64,
tcph->th_mptcp->mh_rawdsn64 + (tcph->th_seglen - 1 ),
packet
);
}
}
PROTO_ITEM_SET_GENERATED(item);
/* We can do this only if rawdsn64 is valid !
if enabled, look for overlapping mappings on other subflows */
if(mptcp_intersubflows_retransmission) {
if(mptcp_intersubflows_retransmission
&& tcph->th_have_seglen
&& tcph->th_seglen) {
wmem_list_frame_t *subflow_it = NULL;
/* results should be some kind of in case 2 DSS are needed to cover this packet */
/* results should be some kind of list in case 2 DSS are needed to cover this packet */
for(subflow_it = wmem_list_head(mptcpd->subflows); subflow_it != NULL; subflow_it = wmem_list_frame_next(subflow_it)) {
struct tcp_analysis *sf_tcpd = (struct tcp_analysis *)wmem_list_frame_data(subflow_it);
struct mptcp_subflow *sf = mptcp_select_subflow_from_meta(sf_tcpd, tcpd->fwd->mptcp_subflow->meta);
/* for current subflow */
if (sf == tcpd->fwd->mptcp_subflow) {
/* skip, was done just before */
/* skip, this is the current subflow */
}
/* in case there were retransmissions on other subflows */
else {
@ -2776,7 +2783,7 @@ mptcp_analysis_dsn_lookup(packet_info *pinfo , tvbuff_t *tvb,
}
}
else {
/* ignore and continue */
/* could not get the rawdsn64, ignore and continue */
}
}
@ -4590,7 +4597,6 @@ dissect_tcpopt_mptcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void*
if (!PINFO_FD_VISITED(pinfo))
{
/* register SSN range described by the mapping into a subflow interval_tree */
mptcp_dss_mapping_t *mapping = NULL;
mapping = wmem_new0(wmem_file_scope(), mptcp_dss_mapping_t);
@ -4601,7 +4607,7 @@ dissect_tcpopt_mptcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void*
mapping->ssn_low = mph->mh_dss_ssn;
mapping->ssn_high = mph->mh_dss_ssn + mph->mh_dss_length-1;
wmem_itree_insert(tcpd->fwd->mptcp_subflow->mappings,
wmem_itree_insert(tcpd->fwd->mptcp_subflow->ssn2dsn_mappings,
mph->mh_dss_ssn,
mapping->ssn_high,
mapping
@ -7564,15 +7570,19 @@ proto_register_tcp(void)
"This frame has some of the MPTCP analysis shown", HFILL }},
{ &hf_mptcp_related_mapping,
{ "Related mapping", "mptcp.related_mapping", FT_FRAMENUM , BASE_NONE, NULL, 0x0,
"Packet in which mapping describing current packet was sent", HFILL }},
{ "Related mapping", "mptcp.related_mapping", FT_FRAMENUM , BASE_NONE, NULL, 0x0,
"Packet in which current packet DSS mapping was sent", HFILL }},
{ &hf_mptcp_duplicated_data,
{ "Was data duplicated", "mptcp.duplicated_dsn", FT_FRAMENUM , BASE_NONE, NULL, 0x0,
{ &hf_mptcp_reinjection_of,
{ "Reinjection of", "mptcp.reinjection_of", FT_FRAMENUM , BASE_NONE, NULL, 0x0,
"This is a retransmission of data sent on another subflow", HFILL }},
{ &hf_mptcp_reinjected_in,
{ "Data reinjected in", "mptcp.reinjected_in", FT_FRAMENUM , BASE_NONE, NULL, 0x0,
"This was retransmitted on another subflow", HFILL }},
{ &hf_mptcp_analysis_subflows,
{ "TCP subflow stream id(s):", "mptcp.analysis.subflows", FT_NONE, BASE_NONE, NULL, 0x0,
{ "TCP subflow stream id(s):", "mptcp.analysis.subflows", FT_NONE, BASE_NONE, NULL, 0x0,
"List all TCP connections mapped to this MPTCP connection", HFILL }},
{ &hf_mptcp_stream,
@ -7752,13 +7762,16 @@ proto_register_tcp(void)
&mptcp_relative_seq);
prefs_register_bool_preference(mptcp_module, "analyze_mappings",
"In depth analysis of Data Sequence Signal (DSS) mappings.",
"Deeper analysis of Data Sequence Signal (DSS)",
"Scales logarithmically with the number of packets"
"You need to capture the handshake for this to work."
"\"Map TCP subflows to their respective MPTCP connections\"",
&mptcp_analyze_mappings);
prefs_register_bool_preference(mptcp_module, "intersubflows_retransmission",
"Check for data duplication across subflows",
"(Greedy algorithm: Scales linearly with number of subflows and"
" logarithmic scaling with number of packets)"
"You need to enable DSS mapping analysis for this option to work",
&mptcp_intersubflows_retransmission);

15
epan/dissectors/packet-tcp.h
View File

@ -257,15 +257,16 @@ struct mptcp_subflow {
guint8 address_id; /* sent during an MP_JOIN */
/* Attempt to map DSN to packets
* Ideally this was to generate application latency
* each node contains a GSList * ?
* this should be done in tap or 3rd party tools
/* map DSN to packets
* Used when looking for reinjections across subflows
*/
wmem_itree_t *dsn_map;
wmem_itree_t *dsn2packet_map;
/* Map SSN to a DSS mappings, each node registers a mptcp_dss_mapping_t */
wmem_itree_t *mappings;
/* Map SSN to a DSS mappings
* a DSS can map DSN to SSNs possibily over several packets,
* hence some packets may have been mapped by previous DSS,
* whence the necessity to be able to look for SSN -> DSN */
wmem_itree_t *ssn2dsn_mappings;
/* meta flow to which it is attached. Helps setting forward and backward meta flow */
mptcp_meta_flow_t *meta;
};

2
epan/wmem/wmem_interval_tree.c
View File

@ -121,7 +121,7 @@ wmem_itree_insert(wmem_itree_t *tree, const guint64 low, const guint64 high, voi
node = wmem_tree_insert(tree, range, data, (compare_func)wmem_tree_compare_ranges);
/* Even If no rotations, still a need to update max_edge */
update_max_edge(node);
update_max_edge(node->parent);
}