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https://github.com/nmap/nmap.git
synced 2026-01-08 23:49:03 +00:00
Clarify and optimize top-ports checking
This commit is contained in:
dmiller
199
services.cc
199
services.cc
@@ -72,6 +72,8 @@
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#include <list>
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#include <map>
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#include <iterator>
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#include <algorithm>
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/* This structure is the key for looking up services in the
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port/proto -> service map. */
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@@ -332,30 +334,32 @@ static int port_compare(const void *a, const void *b) {
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}
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template <typename T>
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class C_array_iterator: public std::iterator<std::random_access_iterator_tag, T, std::ptrdiff_t> {
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T *ptr;
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public:
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C_array_iterator(T *_ptr=NULL) : ptr(_ptr) {}
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C_array_iterator(const C_array_iterator &other) : ptr(other.ptr) {}
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C_array_iterator& operator=(T *_ptr) {ptr = _ptr; return *this;}
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C_array_iterator& operator++() {ptr++; return *this;}
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C_array_iterator operator++(int) {C_array_iterator retval = *this; ++(*this); return retval;}
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C_array_iterator& operator--() {ptr--; return *this;}
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C_array_iterator operator--(int) {C_array_iterator retval = *this; --(*this); return retval;}
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bool operator==(C_array_iterator &other) const {return ptr == other.ptr;}
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bool operator!=(C_array_iterator &other) const {return !(*this == other);}
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bool operator<(C_array_iterator &other) const {return ptr < other.ptr;}
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C_array_iterator& operator+=(std::ptrdiff_t n) {ptr += n; return *this;}
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C_array_iterator& operator-=(std::ptrdiff_t n) {ptr -= n; return *this;}
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std::ptrdiff_t operator+(const C_array_iterator &other) {return ptr + other.ptr;}
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std::ptrdiff_t operator-(const C_array_iterator &other) {return ptr - other.ptr;}
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T& operator*() const {return *ptr;}
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};
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// is_port_member() returns true if serv is an element of ptsdata.
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// This could be implemented MUCH more efficiently but it should only be
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// called when you use a non-default top-ports or port-ratio value TOGETHER WITH
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// a -p portlist.
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static bool is_port_member(const struct scan_lists *ptsdata, const struct service_node *serv) {
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int i;
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if (strcmp(serv->s_proto, "tcp") == 0) {
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for (i=0; i<ptsdata->tcp_count; i++)
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if (serv->s_port == ptsdata->tcp_ports[i])
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return true;
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} else if (strcmp(serv->s_proto, "udp") == 0) {
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for (i=0; i<ptsdata->udp_count; i++)
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if (serv->s_port == ptsdata->udp_ports[i])
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return true;
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} else if (strcmp(serv->s_proto, "sctp") == 0) {
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for (i=0; i<ptsdata->sctp_count; i++)
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if (serv->s_port == ptsdata->sctp_ports[i])
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return true;
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}
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return false;
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// is_port_member() returns true if serv->s_port is an element of pts.
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static bool is_port_member(unsigned short *pts, int count, const struct service_node *serv) {
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C_array_iterator<unsigned short> begin = pts;
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C_array_iterator<unsigned short> end = pts + count;
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return std::binary_search(begin, end, serv->s_port);
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}
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// gettoppts() sets its third parameter, a scan_list, with the most
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@@ -375,7 +379,6 @@ static bool is_port_member(const struct scan_lists *ptsdata, const struct servic
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// function if o.TCPScan() || o.UDPScan() || o.SCTPScan()
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void gettoppts(double level, const char *portlist, struct scan_lists * ports, const char *exclude_ports) {
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int ti=0, ui=0, si=0;
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struct scan_lists ptsdata = { 0 };
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bool ptsdata_initialized = false;
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const struct service_node *current;
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@@ -421,85 +424,83 @@ void gettoppts(double level, const char *portlist, struct scan_lists * ports, co
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if (ptsdata_initialized && exclude_ports)
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removepts(exclude_ports, &ptsdata);
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if (level < 1) {
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for (i = services_by_ratio.begin(); i != services_by_ratio.end(); i++) {
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current = &(*i);
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if (ptsdata_initialized && !is_port_member(&ptsdata, current))
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continue;
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if (current->ratio >= level) {
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if (o.TCPScan() && strcmp(current->s_proto, "tcp") == 0)
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ports->tcp_count++;
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else if (o.UDPScan() && strcmp(current->s_proto, "udp") == 0)
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ports->udp_count++;
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else if (o.SCTPScan() && strcmp(current->s_proto, "sctp") == 0)
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ports->sctp_count++;
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} else {
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break;
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}
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}
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/* Max number of ports for each protocol cannot be more than the minimum of:
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* 1. all of them (65536)
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* 2. requested ports (ptsdata)
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* 3. the number in services db (numXXXports)
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*/
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int tcpmax = o.TCPScan() ? (ptsdata_initialized ? ptsdata.tcp_count : 65536) : 0;
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tcpmax = MIN(tcpmax, numtcpports);
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int udpmax = o.UDPScan() ? (ptsdata_initialized ? ptsdata.udp_count : 65536) : 0;
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udpmax = MIN(udpmax, numudpports);
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int sctpmax = o.SCTPScan() ? (ptsdata_initialized ? ptsdata.sctp_count : 65536) : 0;
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sctpmax = MIN(sctpmax, numsctpports);
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if (ports->tcp_count)
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ports->tcp_ports = (unsigned short *)safe_zalloc(ports->tcp_count * sizeof(unsigned short));
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if (ports->udp_count)
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ports->udp_ports = (unsigned short *)safe_zalloc(ports->udp_count * sizeof(unsigned short));
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if (ports->sctp_count)
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ports->sctp_ports = (unsigned short *)safe_zalloc(ports->sctp_count * sizeof(unsigned short));
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ports->prots = NULL;
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for (i = services_by_ratio.begin(); i != services_by_ratio.end(); i++) {
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current = &(*i);
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if (ptsdata_initialized && !is_port_member(&ptsdata, current))
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continue;
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if (current->ratio >= level) {
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if (o.TCPScan() && strcmp(current->s_proto, "tcp") == 0)
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ports->tcp_ports[ti++] = current->s_port;
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else if (o.UDPScan() && strcmp(current->s_proto, "udp") == 0)
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ports->udp_ports[ui++] = current->s_port;
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else if (o.SCTPScan() && strcmp(current->s_proto, "sctp") == 0)
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ports->sctp_ports[si++] = current->s_port;
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} else {
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break;
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}
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}
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} else if (level >= 1) {
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// If level is positive integer, it's the max number of ports.
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if (level >= 1) {
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if (level > 65536)
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fatal("Level argument to gettoppts (%g) is too large", level);
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if (o.TCPScan()) {
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ports->tcp_count = MIN((int) level, numtcpports);
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ports->tcp_ports = (unsigned short *)safe_zalloc(ports->tcp_count * sizeof(unsigned short));
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}
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if (o.UDPScan()) {
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ports->udp_count = MIN((int) level, numudpports);
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ports->udp_ports = (unsigned short *)safe_zalloc(ports->udp_count * sizeof(unsigned short));
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}
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if (o.SCTPScan()) {
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ports->sctp_count = MIN((int) level, numsctpports);
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ports->sctp_ports = (unsigned short *)safe_zalloc(ports->sctp_count * sizeof(unsigned short));
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}
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ports->prots = NULL;
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for (i = services_by_ratio.begin(); i != services_by_ratio.end(); i++) {
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current = &(*i);
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if (ptsdata_initialized && !is_port_member(&ptsdata, current))
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continue;
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if (o.TCPScan() && strcmp(current->s_proto, "tcp") == 0 && ti < ports->tcp_count)
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ports->tcp_ports[ti++] = current->s_port;
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else if (o.UDPScan() && strcmp(current->s_proto, "udp") == 0 && ui < ports->udp_count)
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ports->udp_ports[ui++] = current->s_port;
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else if (o.SCTPScan() && strcmp(current->s_proto, "sctp") == 0 && si < ports->sctp_count)
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ports->sctp_ports[si++] = current->s_port;
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}
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if (ti < ports->tcp_count) ports->tcp_count = ti;
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if (ui < ports->udp_count) ports->udp_count = ui;
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if (si < ports->sctp_count) ports->sctp_count = si;
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} else
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tcpmax = MIN((int) level, tcpmax);
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udpmax = MIN((int) level, udpmax);
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sctpmax = MIN((int) level, sctpmax);
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// Now force the ratio comparison to always be true:
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level = 0;
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}
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else if (level <= 0) {
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fatal("Argument to gettoppts (%g) should be a positive ratio below 1 or an integer of 1 or higher", level);
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}
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// else level is a ratio between 0 and 1
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// These could be 0/false if the scan type was not requested.
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if (tcpmax) {
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ports->tcp_ports = (unsigned short *)safe_zalloc(tcpmax * sizeof(unsigned short));
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}
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if (udpmax) {
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ports->udp_ports = (unsigned short *)safe_zalloc(udpmax * sizeof(unsigned short));
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}
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if (sctpmax) {
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ports->sctp_ports = (unsigned short *)safe_zalloc(sctpmax * sizeof(unsigned short));
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}
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ports->prots = NULL;
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// Loop until we get enough or run out of candidates
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for (i = services_by_ratio.begin(); i != services_by_ratio.end() && (tcpmax || udpmax || sctpmax); i++) {
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current = &(*i);
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if (current->ratio < level) {
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break;
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}
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switch (current->s_proto[0]) {
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case 't':
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if (tcpmax && strcmp(current->s_proto, "tcp") == 0
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&& (!ptsdata_initialized ||
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is_port_member(ptsdata.tcp_ports, ptsdata.tcp_count, current))
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) {
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ports->tcp_ports[ports->tcp_count++] = current->s_port;
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tcpmax--;
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}
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break;
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case 'u':
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if (udpmax && strcmp(current->s_proto, "udp") == 0
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&& (!ptsdata_initialized ||
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is_port_member(ptsdata.udp_ports, ptsdata.udp_count, current))
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) {
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ports->udp_ports[ports->udp_count++] = current->s_port;
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udpmax--;
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}
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break;
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case 's':
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if (sctpmax && strcmp(current->s_proto, "sctp") == 0
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&& (!ptsdata_initialized ||
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is_port_member(ptsdata.sctp_ports, ptsdata.sctp_count, current))
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)
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ports->sctp_ports[ports->sctp_count++] = current->s_port;
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sctpmax--;
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break;
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default:
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break;
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}
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}
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if (ptsdata_initialized) {
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free_scan_lists(&ptsdata);
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