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Improve the efficiency of loading the nmap-services file. We now use an STL map

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instead of a custom hash table and an STL list instead of a custom linked list.
The biggest gain comes from using the list.sort method rather than inserting
ports in sorted order (equivalent to insertion sort). The new code passes
Doug's p-switch-tests.

Here are time comparisons, using the old and new services code, and using the
standard nmap-services file and the 65535-port nmap-services-huge. The times
are the duration of the call to nmap_services_init. Three trials were done for
each case, except for the old-code/nmap-services-huge case.

nmap-services:
old code:   0.215  0.201  0.227  (average   0.214 s)
new code:   0.025  0.022  0.023  (average   0.023 s)

nmap-services-huge:
old code: 441.014                (average 441.014 s)
new code:   0.984  0.975  0.978  (average   0.979 s)
This commit is contained in:
david
2008-08-13 01:19:09 +00:00
parent 931285f765
commit 3a67da3a7e
2 changed files with 127 additions and 121 deletions
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242
services.cc
View File

@@ -99,17 +99,49 @@
/* $Id$ */ /* $Id$ */
#include <list>
#include <map>
#include "services.h" #include "services.h"
#include "NmapOps.h" #include "NmapOps.h"
#include "charpool.h" #include "charpool.h"
#include "nmap_error.h" #include "nmap_error.h"
#include "utils.h" #include "utils.h"
/* This structure is the key for looking up services in the
port/proto -> service map. */
struct port_spec {
int portno; /* Network byte order */
std::string proto;
/* Sort in the usual nmap-services order. */
bool operator<(const port_spec& other) const {
if (this->portno < other.portno)
return true;
else if (this->portno > other.portno)
return false;
else
return this->proto < other.proto;
}
};
/* This is a servent augmented by a frequency ratio. */
struct service_node : public servent {
public:
double ratio;
};
/* Compare the ratios of two service nodes for top-ports purposes. Larger ratios
come before smaller. */
bool service_node_ratio_compare(const service_node& a, const service_node& b) {
return a.ratio > b.ratio;
}
extern NmapOps o; extern NmapOps o;
static int numtcpports = 0; static int numtcpports = 0;
static int numudpports = 0; static int numudpports = 0;
static struct service_list *service_table[SERVICE_TABLE_SIZE]; static std::map<port_spec, service_node> service_table;
static struct service_list *sorted_services = NULL; static std::list<service_node> services_by_ratio;
static int services_initialized = 0; static int services_initialized = 0;
static int ratio_format = 0; // 0 = /etc/services no-ratio format. 1 = new nmap format static int ratio_format = 0; // 0 = /etc/services no-ratio format. 1 = new nmap format
@@ -123,7 +155,6 @@ static int nmap_services_init() {
char *p; char *p;
char line[1024]; char line[1024];
int lineno = 0; int lineno = 0;
struct service_list *current, *previous, *sp;
int res; int res;
double ratio; double ratio;
int ratio_n, ratio_d; int ratio_n, ratio_d;
@@ -159,8 +190,6 @@ static int nmap_services_init() {
/* Record where this data file was found. */ /* Record where this data file was found. */
o.loaded_data_files["nmap-services"] = filename; o.loaded_data_files["nmap-services"] = filename;
memset(service_table, 0, sizeof(service_table));
while(fgets(line, sizeof(line), fp)) { while(fgets(line, sizeof(line), fp)) {
lineno++; lineno++;
p = line; p = line;
@@ -191,21 +220,18 @@ static int nmap_services_init() {
portno = htons(portno); portno = htons(portno);
port_spec ps;
ps.portno = portno;
ps.proto = proto;
/* Now we make sure our service table doesn't have duplicates */ /* Now we make sure our service table doesn't have duplicates */
for(current = service_table[portno % SERVICE_TABLE_SIZE], previous = NULL; std::map<port_spec, service_node>::iterator i;
current; current = current->next) { i = service_table.find(ps);
if (portno == (u16) current->servent->s_port && if (i != service_table.end()) {
strcasecmp(proto, current->servent->s_proto) == 0) { if (o.debugging)
if (o.debugging) { error("Port %d proto %s is duplicated in services file %s", ntohs(portno), proto, filename);
error("Port %d proto %s is duplicated in services file %s", ntohs(portno), proto, filename);
}
break;
}
previous = current;
}
/* Current service in the file was a duplicate, get another one */
if (current)
continue; continue;
}
if (strncasecmp(proto, "tcp", 3) == 0) { if (strncasecmp(proto, "tcp", 3) == 0) {
numtcpports++; numtcpports++;
@@ -223,42 +249,22 @@ static int nmap_services_init() {
continue; continue;
} }
current = (struct service_list *) cp_alloc(sizeof(struct service_list)); struct service_node sn;
current->servent = (struct servent *) cp_alloc(sizeof(struct servent));
current->ratio = ratio;
current->next = NULL;
if (previous == NULL) {
service_table[portno % SERVICE_TABLE_SIZE] = current;
} else {
previous->next = current;
}
current->servent->s_name = cp_strdup(servicename);
current->servent->s_port = portno;
current->servent->s_proto = cp_strdup(proto);
current->servent->s_aliases = NULL;
sp = (struct service_list *) cp_alloc(sizeof(struct service_list)); sn.s_name = cp_strdup(servicename);
sp->servent = current->servent; sn.s_port = portno;
sp->ratio = current->ratio; sn.s_proto = cp_strdup(proto);
sp->next = NULL; sn.s_aliases = NULL;
sn.ratio = ratio;
if (sorted_services == NULL || sorted_services->ratio < sp->ratio) { service_table[ps] = sn;
sp->next = sorted_services;
sorted_services = sp;
} else
for (current=sorted_services;;current=current->next) {
if (current->next == NULL) {
current->next = sp;
break;
} else if (current->next->ratio < sp->ratio) {
sp->next = current->next;
current->next = sp;
break;
}
}
services_by_ratio.push_back(sn);
} }
/* Sort the list of ports sorted by frequency for top-ports purposes. */
services_by_ratio.sort(service_node_ratio_compare);
fclose(fp); fclose(fp);
services_initialized = 1; services_initialized = 1;
return 0; return 0;
@@ -273,52 +279,47 @@ static int nmap_services_init() {
*/ */
int addportsfromservmask(char *mask, u8 *porttbl, int range_type) { int addportsfromservmask(char *mask, u8 *porttbl, int range_type) {
struct service_list *current; std::map<port_spec, service_node>::iterator i;
int bucket,t=0; int t = 0;
if (!services_initialized && nmap_services_init() == -1) if (!services_initialized && nmap_services_init() == -1)
fatal("%s: Couldn't get port numbers", __func__); fatal("%s: Couldn't get port numbers", __func__);
for(bucket = 0; bucket < SERVICE_TABLE_SIZE; bucket++) { for (i = service_table.begin(); i != service_table.end(); i++) {
for(current = service_table[bucket % SERVICE_TABLE_SIZE]; current; current = current->next) { service_node& current = i->second;
if (wildtest(mask, current->servent->s_name)) { if (wildtest(mask, current.s_name)) {
if ((range_type & SCAN_TCP_PORT) && strcmp(current.s_proto, "tcp") == 0) {
if ((range_type & SCAN_TCP_PORT) && strcmp(current->servent->s_proto, "tcp") == 0) { porttbl[ntohs(current.s_port)] |= SCAN_TCP_PORT;
porttbl[ntohs(current->servent->s_port)] |= SCAN_TCP_PORT; t++;
t++; }
} if ((range_type & SCAN_UDP_PORT) && strcmp(current.s_proto, "udp") == 0) {
porttbl[ntohs(current.s_port)] |= SCAN_UDP_PORT;
if ((range_type & SCAN_UDP_PORT) && strcmp(current->servent->s_proto, "udp") == 0) { t++;
porttbl[ntohs(current->servent->s_port)] |= SCAN_UDP_PORT;
t++;
}
} }
} }
} }
return t; return t;
} }
/* Port must be in network byte order. */
struct servent *nmap_getservbyport(int port, const char *proto) { struct servent *nmap_getservbyport(int port, const char *proto) {
struct service_list *current; std::map<port_spec, service_node>::iterator i;
port_spec ps;
if (nmap_services_init() == -1) if (nmap_services_init() == -1)
return NULL; return NULL;
for(current = service_table[port % SERVICE_TABLE_SIZE]; ps.portno = port;
current; current = current->next) { ps.proto = proto;
if (((u16) port == (u16) current->servent->s_port) && i = service_table.find(ps);
strcmp(proto, current->servent->s_proto) == 0) if (i != service_table.end())
return current->servent; return &i->second;
}
/* Couldn't find it ... oh well. */ /* Couldn't find it ... oh well. */
return NULL; return NULL;
} }
@@ -336,18 +337,20 @@ static int port_compare(const void *a, const void *b) {
// called when you use a non-default top-ports or port-ratio value TOGETHER WITH // called when you use a non-default top-ports or port-ratio value TOGETHER WITH
// a -p portlist. // a -p portlist.
static int is_port_member(struct scan_lists *ptsdata, struct service_list *serv) { static bool is_port_member(const struct scan_lists *ptsdata, const struct service_node *serv) {
int i; int i;
if (serv->servent->s_proto[0] == 't') { if (strcmp(serv->s_proto, "tcp") == 0) {
for (i=0; i<ptsdata->tcp_count; i++) for (i=0; i<ptsdata->tcp_count; i++)
if (ntohs(serv->servent->s_port) == ptsdata->tcp_ports[i]) return 1; if (ntohs(serv->s_port) == ptsdata->tcp_ports[i])
} else { return true;
} else if (strcmp(serv->s_proto, "udp") == 0) {
for (i=0; i<ptsdata->udp_count; i++) for (i=0; i<ptsdata->udp_count; i++)
if (ntohs(serv->servent->s_port) == ptsdata->udp_ports[i]) return 1; if (ntohs(serv->s_port) == ptsdata->udp_ports[i])
return true;
} }
return 0; return false;
} }
// gettoppts() sets its third parameter, a scan_list, with the most // gettoppts() sets its third parameter, a scan_list, with the most
@@ -367,7 +370,8 @@ void gettoppts(double level, char *portlist, struct scan_lists * ports) {
int ti=0, ui=0; int ti=0, ui=0;
struct scan_lists ptsdata = { 0 }; struct scan_lists ptsdata = { 0 };
bool ptsdata_initialized = false; bool ptsdata_initialized = false;
struct service_list *current; const struct service_node *current;
std::list<service_node>::iterator i;
if (!services_initialized && nmap_services_init() == -1) if (!services_initialized && nmap_services_init() == -1)
fatal("%s: Couldn't get port numbers", __func__); fatal("%s: Couldn't get port numbers", __func__);
@@ -399,60 +403,68 @@ void gettoppts(double level, char *portlist, struct scan_lists * ports) {
} }
if (portlist){ if (portlist){
getpts(portlist, &ptsdata); getpts(portlist, &ptsdata);
ptsdata_initialized = true; ptsdata_initialized = true;
} }
if (level < 1) { if (level < 1) {
for (current=sorted_services; current; current=current->next) { for (i = services_by_ratio.begin(); i != services_by_ratio.end(); i++) {
if (ptsdata_initialized && !is_port_member(&ptsdata, current)) continue; current = &(*i);
if (ptsdata_initialized && !is_port_member(&ptsdata, current))
continue;
if (current->ratio >= level) { if (current->ratio >= level) {
if (o.TCPScan() && current->servent->s_proto[0] == 't') ports->tcp_count++; if (o.TCPScan() && strcmp(current->s_proto, "tcp") == 0)
else if (o.UDPScan() && current->servent->s_proto[0] == 'u') ports->udp_count++; ports->tcp_count++;
} else break; else if (o.UDPScan() && strcmp(current->s_proto, "udp") == 0)
ports->udp_count++;
} else {
break;
}
} }
if (ports->tcp_count) if (ports->tcp_count)
ports->tcp_ports = (unsigned short *)safe_zalloc(ports->tcp_count * sizeof(unsigned short)); ports->tcp_ports = (unsigned short *)safe_zalloc(ports->tcp_count * sizeof(unsigned short));
if (ports->udp_count) if (ports->udp_count)
ports->udp_ports = (unsigned short *)safe_zalloc(ports->udp_count * sizeof(unsigned short)); ports->udp_ports = (unsigned short *)safe_zalloc(ports->udp_count * sizeof(unsigned short));
ports->prots = NULL; ports->prots = NULL;
for (current=sorted_services;current;current=current->next) { for (i = services_by_ratio.begin(); i != services_by_ratio.end(); i++) {
if (ptsdata_initialized && !is_port_member(&ptsdata, current)) continue; current = &(*i);
if (ptsdata_initialized && !is_port_member(&ptsdata, current))
continue;
if (current->ratio >= level) { if (current->ratio >= level) {
if (o.TCPScan() && current->servent->s_proto[0] == 't') if (o.TCPScan() && strcmp(current->s_proto, "tcp") == 0)
ports->tcp_ports[ti++] = ntohs(current->servent->s_port); ports->tcp_ports[ti++] = ntohs(current->s_port);
else if (o.UDPScan() && current->servent->s_proto[0] == 'u') else if (o.UDPScan() && strcmp(current->s_proto, "udp") == 0)
ports->udp_ports[ui++] = ntohs(current->servent->s_port); ports->udp_ports[ui++] = ntohs(current->s_port);
} else break; } else {
break;
}
} }
} else if (level >= 1) { } else if (level >= 1) {
if (level > 65536) if (level > 65536)
fatal("Level argument to gettoppts (%g) is too large", level); fatal("Level argument to gettoppts (%g) is too large", level);
if (o.TCPScan()) { if (o.TCPScan()) {
ports->tcp_count = MIN((int) level, numtcpports); ports->tcp_count = MIN((int) level, numtcpports);
ports->tcp_ports = (unsigned short *)safe_zalloc(ports->tcp_count * sizeof(unsigned short)); ports->tcp_ports = (unsigned short *)safe_zalloc(ports->tcp_count * sizeof(unsigned short));
} }
if (o.UDPScan()) { if (o.UDPScan()) {
ports->udp_count = MIN((int) level, numudpports); ports->udp_count = MIN((int) level, numudpports);
ports->udp_ports = (unsigned short *)safe_zalloc(ports->udp_count * sizeof(unsigned short)); ports->udp_ports = (unsigned short *)safe_zalloc(ports->udp_count * sizeof(unsigned short));
} }
ports->prots = NULL; ports->prots = NULL;
for (current=sorted_services;current && (ti < ports->tcp_count || ui < ports->udp_count);current=current->next) { for (i = services_by_ratio.begin(); i != services_by_ratio.end(); i++) {
if (ptsdata_initialized && !is_port_member(&ptsdata, current)) continue; current = &(*i);
if (ptsdata_initialized && !is_port_member(&ptsdata, current))
if (o.TCPScan() && current->servent->s_proto[0] == 't' && ti < ports->tcp_count) continue;
ports->tcp_ports[ti++] = ntohs(current->servent->s_port); if (o.TCPScan() && strcmp(current->s_proto, "tcp") == 0 && ti < ports->tcp_count)
else if (o.UDPScan() && current->servent->s_proto[0] == 'u' && ui < ports->udp_count) ports->tcp_ports[ti++] = ntohs(current->s_port);
ports->udp_ports[ui++] = ntohs(current->servent->s_port); else if (o.UDPScan() && strcmp(current->s_proto, "udp") == 0 && ui < ports->udp_count)
ports->udp_ports[ui++] = ntohs(current->s_port);
} }
if (ti < ports->tcp_count) ports->tcp_count = ti; if (ti < ports->tcp_count) ports->tcp_count = ti;
@@ -466,14 +478,14 @@ void gettoppts(double level, char *portlist, struct scan_lists * ports) {
} }
if (ports->tcp_count > 1) if (ports->tcp_count > 1)
qsort(ports->tcp_ports, ports->tcp_count, sizeof(unsigned short), &port_compare); qsort(ports->tcp_ports, ports->tcp_count, sizeof(unsigned short), &port_compare);
if (ports->udp_count > 1) if (ports->udp_count > 1)
qsort(ports->udp_ports, ports->udp_count, sizeof(unsigned short), &port_compare); qsort(ports->udp_ports, ports->udp_count, sizeof(unsigned short), &port_compare);
if (o.debugging && level < 1) if (o.debugging && level < 1)
log_write(LOG_STDOUT, "PORTS: Using ports open on %g%% or more average hosts (TCP:%d, UDP:%d)\n", level*100, ports->tcp_count, ports->udp_count); log_write(LOG_STDOUT, "PORTS: Using ports open on %g%% or more average hosts (TCP:%d, UDP:%d)\n", level*100, ports->tcp_count, ports->udp_count);
else if (o.debugging && level >= 1) else if (o.debugging && level >= 1)
log_write(LOG_STDOUT, "PORTS: Using top %d ports found open (TCP:%d, UDP:%d)\n", (int) level, ports->tcp_count, ports->udp_count); log_write(LOG_STDOUT, "PORTS: Using top %d ports found open (TCP:%d, UDP:%d)\n", (int) level, ports->tcp_count, ports->udp_count);
} }

6
services.h
View File

@@ -122,12 +122,6 @@
#define SCAN_UDP_PORT (1 << 1) #define SCAN_UDP_PORT (1 << 1)
#define SCAN_PROTOCOLS (1 << 2) #define SCAN_PROTOCOLS (1 << 2)
struct service_list {
struct servent *servent;
double ratio;
struct service_list *next;
};
int addportsfromservmask(char *mask, u8 *porttbl, int range_type); int addportsfromservmask(char *mask, u8 *porttbl, int range_type);
struct servent *nmap_getservbyport(int port, const char *proto); struct servent *nmap_getservbyport(int port, const char *proto);
void gettoppts(double level, char *portlist, struct scan_lists * ports); void gettoppts(double level, char *portlist, struct scan_lists * ports);