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Replace ConnList linked list with multiset

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Keeping a sorted multi-set allows faster search by source /
source+destination address.

Fixes O(n^2) complexity when handling a lot of connections (now it's
O(n log n)).
This commit is contained in:
Vladimir Panteleev
2022-03-23 17:28:09 +00:00
parent f46954525d
commit 92fb73116a
6 changed files with 100 additions and 96 deletions
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63
src/connection.cpp
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@@ -33,7 +33,7 @@
#include "nethogs.h"
#include "process.h"
ConnList *connections = NULL;
ConnList connections;
extern Process *unknownudp;
void PackList::add(Packet *p) {
@@ -78,7 +78,6 @@ u_int64_t PackList::sumanddel(timeval t) {
/* packet may be deleted by caller */
Connection::Connection(Packet *packet) {
assert(packet != NULL);
connections = new ConnList(this, connections);
sent_packets = new PackList();
recv_packets = new PackList();
sumSent = 0;
@@ -96,6 +95,7 @@ Connection::Connection(Packet *packet) {
recv_packets->add(packet);
refpacket = packet->newInverted();
}
connections.insert(this);
lastpacket = packet->time.tv_sec;
if (DEBUG)
std::cout << "New reference packet created at " << refpacket << std::endl;
@@ -104,6 +104,13 @@ Connection::Connection(Packet *packet) {
Connection::~Connection() {
if (DEBUG)
std::cout << "Deleting connection" << std::endl;
auto r = connections.equal_range(this);
for (auto it = r.first; it != r.second; ++it) {
if (*it == this) {
connections.erase(it);
break;
}
}
/* refpacket is not a pointer to one of the packets in the lists
* so deleted */
delete (refpacket);
@@ -111,24 +118,6 @@ Connection::~Connection() {
delete sent_packets;
if (recv_packets != NULL)
delete recv_packets;
ConnList *curr_conn = connections;
ConnList *prev_conn = NULL;
while (curr_conn != NULL) {
if (curr_conn->getVal() == this) {
ConnList *todelete = curr_conn;
curr_conn = curr_conn->getNext();
if (prev_conn == NULL) {
connections = curr_conn;
} else {
prev_conn->setNext(curr_conn);
}
delete (todelete);
} else {
prev_conn = curr_conn;
curr_conn = curr_conn->getNext();
}
}
}
/* the packet will be freed by the calling code */
@@ -156,26 +145,24 @@ Connection *findConnectionWithMatchingSource(Packet *packet,
short int packettype) {
assert(packet->Outgoing());
ConnList *current = NULL;
ConnList *connList = NULL;
switch (packettype) {
case IPPROTO_TCP: {
current = connections;
connList = &connections;
break;
}
case IPPROTO_UDP: {
current = unknownudp->connections;
connList = &unknownudp->connections;
break;
}
}
while (current != NULL) {
/* the reference packet is always outgoing */
if (packet->matchSource(current->getVal()->refpacket)) {
return current->getVal();
}
current = current->getNext();
Packet p = packet->onlySource();
auto it = connList->lower_bound(&p);
/* the reference packet is always outgoing */
if (it != connList->end() && packet->matchSource((*it)->refpacket)) {
return *it;
}
return NULL;
@@ -184,25 +171,23 @@ Connection *findConnectionWithMatchingSource(Packet *packet,
Connection *findConnectionWithMatchingRefpacketOrSource(Packet *packet,
short int packettype) {
ConnList *current = NULL;
ConnList *connList = NULL;
switch (packettype) {
case IPPROTO_TCP: {
current = connections;
connList = &connections;
break;
}
case IPPROTO_UDP: {
current = unknownudp->connections;
connList = &unknownudp->connections;
break;
}
}
while (current != NULL) {
/* the reference packet is always *outgoing* */
if (packet->match(current->getVal()->refpacket)) {
return current->getVal();
}
current = current->getNext();
auto it = connList->lower_bound(packet);
/* the reference packet is always *outgoing* */
if (it != connList->end() && packet->match((*it)->refpacket)) {
return *it;
}
return findConnectionWithMatchingSource(packet, packettype);