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Replace ConnList linked list with multiset

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

59
src/connection.cpp
View File

@@ -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) {
Packet p = packet->onlySource();
auto it = connList->lower_bound(&p);
/* the reference packet is always outgoing */
if (packet->matchSource(current->getVal()->refpacket)) {
return current->getVal();
}
current = current->getNext();
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) {
auto it = connList->lower_bound(packet);
/* the reference packet is always *outgoing* */
if (packet->match(current->getVal()->refpacket)) {
return current->getVal();
}
current = current->getNext();
if (it != connList->end() && packet->match((*it)->refpacket)) {
return *it;
}
return findConnectionWithMatchingSource(packet, packettype);

7
src/cui.cpp
View File

@@ -332,13 +332,10 @@ void show_trace(Line *lines[], int nproc) {
}
/* print the 'unknown' connections, for debugging */
ConnList *curr_unknownconn = unknowntcp->connections;
while (curr_unknownconn != NULL) {
for (auto it = unknowntcp->connections.begin(); it != unknowntcp->connections.end(); ++it) {
std::cout << "Unknown connection: "
<< curr_unknownconn->getVal()->refpacket->gethashstring()
<< (*it)->refpacket->gethashstring()
<< std::endl;
curr_unknownconn = curr_unknownconn->getNext();
}
}

41
src/packet.cpp
View File

@@ -289,7 +289,7 @@ char *Packet::gethashstring() {
/* 2 packets match if they have the same
* source and destination ports and IP's. */
bool Packet::match(Packet *other) {
bool Packet::match(const Packet *other) const {
return sa_family == other->sa_family && (sport == other->sport) &&
(dport == other->dport) &&
(sa_family == AF_INET
@@ -298,9 +298,46 @@ bool Packet::match(Packet *other) {
(samein6addr(dip6, other->dip6)));
}
bool Packet::matchSource(Packet *other) {
bool Packet::matchSource(const Packet *other) const {
return sa_family == other->sa_family && (sport == other->sport) &&
(sa_family == AF_INET
? (sameinaddr(sip, other->sip))
: (samein6addr(sip6, other->sip6)));
}
Packet Packet::onlySource() const {
Packet p = *this;
std::fill(std::begin(p.dip6.s6_addr), std::end(p.dip6.s6_addr), 0);
p.dip.s_addr = 0;
p.dport = 0;
return p;
}
bool Packet::operator< (const Packet& other) const {
if (sa_family != other.sa_family)
return dir < other.sa_family;
/* source address first */
if (sport != other.sport)
return sport < other.sport;
if (sa_family == AF_INET) {
if (sip.s_addr != other.sip.s_addr)
return sip.s_addr < other.sip.s_addr;
} else {
for (int i = 0; i < 16; i++)
if (sip6.s6_addr[i] != other.sip6.s6_addr[i])
return sip6.s6_addr[i] < other.sip6.s6_addr[i];
}
/* destination address second */
if (dport != other.dport)
return dport < other.dport;
if (sa_family == AF_INET) {
if (dip.s_addr != other.dip.s_addr)
return dip.s_addr < other.dip.s_addr;
} else {
for (int i = 0; i < 16; i++)
if (dip6.s6_addr[i] != other.dip6.s6_addr[i])
return dip6.s6_addr[i] < other.dip6.s6_addr[i];
}
/* equal */
return false;
}

7
src/packet.h
View File

@@ -70,8 +70,11 @@ public:
/* is this packet coming from the local host? */
bool Outgoing();
bool match(Packet *other);
bool matchSource(Packet *other);
bool match(const Packet *other) const;
bool matchSource(const Packet *other) const;
/* returns a copy with destination information stripped (for comparisons) */
Packet onlySource() const;
bool operator< (const Packet& other) const;
/* returns '1.2.3.4:5-1.2.3.4:6'-style string */
char *gethashstring();

45
src/process.cpp
View File

@@ -97,13 +97,10 @@ void process_init() {
int Process::getLastPacket() {
int lastpacket = 0;
ConnList *curconn = connections;
while (curconn != NULL) {
assert(curconn != NULL);
assert(curconn->getVal() != NULL);
if (curconn->getVal()->getLastPacket() > lastpacket)
lastpacket = curconn->getVal()->getLastPacket();
curconn = curconn->getNext();
for (auto it = connections.begin(); it != connections.end(); ++it) {
assert(*it != NULL);
if ((*it)->getLastPacket() > lastpacket)
lastpacket = (*it)->getLastPacket();
}
return lastpacket;
}
@@ -113,30 +110,20 @@ static void sum_active_connections(Process *process_ptr, u_int64_t &sum_sent,
u_int64_t &sum_recv) {
/* walk though all process_ptr process's connections, and sum
* them up */
ConnList *curconn = process_ptr->connections;
ConnList *previous = NULL;
while (curconn != NULL) {
if (curconn->getVal()->getLastPacket() <= curtime.tv_sec - CONNTIMEOUT) {
for (auto it = process_ptr->connections.begin(); it != process_ptr->connections.end(); ) {
if ((*it)->getLastPacket() <= curtime.tv_sec - CONNTIMEOUT) {
/* capture sent and received totals before deleting */
process_ptr->sent_by_closed_bytes += curconn->getVal()->sumSent;
process_ptr->rcvd_by_closed_bytes += curconn->getVal()->sumRecv;
process_ptr->sent_by_closed_bytes += (*it)->sumSent;
process_ptr->rcvd_by_closed_bytes += (*it)->sumRecv;
/* stalled connection, remove. */
ConnList *todelete = curconn;
Connection *conn_todelete = curconn->getVal();
curconn = curconn->getNext();
if (todelete == process_ptr->connections)
process_ptr->connections = curconn;
if (previous != NULL)
previous->setNext(curconn);
delete (todelete);
delete (conn_todelete);
delete (*it);
it = process_ptr->connections.erase(it);
} else {
u_int64_t sent = 0, recv = 0;
curconn->getVal()->sumanddel(curtime, &recv, &sent);
(*it)->sumanddel(curtime, &recv, &sent);
sum_sent += sent;
sum_recv += recv;
previous = curconn;
curconn = curconn->getNext();
++it;
}
}
}
@@ -171,12 +158,10 @@ void Process::getgbps(float *recvd, float *sent) {
/** get total values for this process */
void Process::gettotal(u_int64_t *recvd, u_int64_t *sent) {
u_int64_t sum_sent = 0, sum_recv = 0;
ConnList *curconn = this->connections;
while (curconn != NULL) {
Connection *conn = curconn->getVal();
for (auto it = this->connections.begin(); it != this->connections.end(); ++it) {
Connection *conn = (*it);
sum_sent += conn->sumSent;
sum_recv += conn->sumRecv;
curconn = curconn->getNext();
}
// std::cout << "Sum sent: " << sum_sent << std::endl;
// std::cout << "Sum recv: " << sum_recv << std::endl;
@@ -403,7 +388,7 @@ Process *getProcess(Connection *connection, const char *devicename,
processes = new ProcList(proc, processes);
}
proc->connections = new ConnList(connection, proc->connections);
proc->connections.insert(connection);
return proc;
}

33
src/process.h
View File

@@ -26,32 +26,30 @@
#include "connection.h"
#include "nethogs.h"
#include <cassert>
#include <set>
extern bool tracemode;
extern bool bughuntmode;
void check_all_procs();
class ConnList {
public:
ConnList(Connection *m_val, ConnList *m_next) {
assert(m_val != NULL);
val = m_val;
next = m_next;
/* compares Connection pointers by their refpacket */
struct ConnectionComparator {
using is_transparent = void;
bool operator()(const Connection* l, const Connection* r) const {
return *l->refpacket < *r->refpacket;
}
~ConnList() {
/* does not delete its value, to allow a connection to
* remove itself from the global connlist in its destructor */
bool operator()(const Packet* l, const Connection* r) const {
return *l < *r->refpacket;
}
bool operator()(const Connection* l, const Packet* r) const {
return *l->refpacket < *r;
}
Connection *getVal() { return val; }
void setNext(ConnList *m_next) { next = m_next; }
ConnList *getNext() { return next; }
private:
Connection *val;
ConnList *next;
};
/* ordered set of Connection pointers */
typedef std::multiset<Connection*, ConnectionComparator> ConnList;
class Process {
public:
/* the process makes a copy of the name. the device name needs to be stable.
@@ -75,7 +73,6 @@ public:
cmdline = strdup(m_cmdline);
devicename = m_devicename;
connections = NULL;
pid = 0;
uid = 0;
sent_by_closed_bytes = 0;
@@ -106,7 +103,7 @@ public:
u_int64_t sent_by_closed_bytes;
u_int64_t rcvd_by_closed_bytes;
ConnList *connections;
ConnList connections;
uid_t getUid() { return uid; }
void setUid(uid_t m_uid) { uid = m_uid; }