nmap/scan_engine.cc at master · nmap/nmap

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	/***************************************************************************
	* scan_engine.cc -- Includes much of the "engine" functions for scanning, *
	* such as ultra_scan. It also includes dependent functions such as those *
	* for collecting SYN/connect scan responses. *
	* *
	*********************IMPORTANT NMAP LICENSE TERMS**********************
	* *
	* The Nmap Security Scanner is (C) 1996-2020 Insecure.Com LLC ("The Nmap *
	* Project"). Nmap is also a registered trademark of the Nmap Project. *
	* *
	* This program is distributed under the terms of the Nmap Public Source *
	* License (NPSL). The exact license text applying to a particular Nmap *
	* release or source code control revision is contained in the LICENSE *
	* file distributed with that version of Nmap or source code control *
	* revision. More Nmap copyright/legal information is available from *
	* https://nmap.org/book/man-legal.html, and further information on the *
	* NPSL license itself can be found at https://nmap.org/npsl. This header *
	* summarizes some key points from the Nmap license, but is no substitute *
	* for the actual license text. *
	* *
	* Nmap is generally free for end users to download and use themselves, *
	* including commercial use. It is available from https://nmap.org. *
	* *
	* The Nmap license generally prohibits companies from using and *
	* redistributing Nmap in commercial products, but we sell a special Nmap *
	* OEM Edition with a more permissive license and special features for *
	* this purpose. See https://nmap.org/oem *
	* *
	* If you have received a written Nmap license agreement or contract *
	* stating terms other than these (such as an Nmap OEM license), you may *
	* choose to use and redistribute Nmap under those terms instead. *
	* *
	* The official Nmap Windows builds include the Npcap software *
	* (https://npcap.org) for packet capture and transmission. It is under *
	* separate license terms which forbid redistribution without special *
	* permission. So the official Nmap Windows builds may not be *
	* redistributed without special permission (such as an Nmap OEM *
	* license). *
	* *
	* Source is provided to this software because we believe users have a *
	* right to know exactly what a program is going to do before they run it. *
	* This also allows you to audit the software for security holes. *
	* *
	* Source code also allows you to port Nmap to new platforms, fix bugs, *
	* and add new features. You are highly encouraged to submit your *
	* changes as a Github PR or by email to the [email protected] mailing list *
	* for possible incorporation into the main distribution. Unless you *
	* specify otherwise, it is understood that you are offering us very *
	* broad rights to use your submissions as described in the Nmap Public *
	* Source License Contributor Agreement. This is important because we *
	* fund the project by selling licenses with various terms, and also *
	* because the inability to relicense code has caused devastating *
	* problems for other Free Software projects (such as KDE and NASM). *
	* *
	* The free version of Nmap is distributed in the hope that it will be *
	* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of *
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Warranties, *
	* indemnification and commercial support are all available through the *
	* Npcap OEM program--see https://nmap.org/oem. *
	* *
	***************************************************************************/

	/* $Id$ */

	#ifdef WIN32
	#include "nmap_winconfig.h"
	#endif
	#include "portreasons.h"
	#include <dnet.h>
	#include "scan_engine.h"
	#include "scan_engine_connect.h"
	#include "scan_engine_raw.h"
	#include "timing.h"
	#include "tcpip.h"
	#include "NmapOps.h"
	#include "nmap_tty.h"
	#include "payload.h"
	#include "Target.h"
	#include "targets.h"
	#include "utils.h"
	#include "nmap_error.h"
	#include "output.h"

	#include "struct_ip.h"

	#ifndef IPPROTO_SCTP
	#include "libnetutil/netutil.h"
	#endif

	#include <math.h>
	#include <list>
	#include <map>

	extern NmapOps o;
	#ifdef WIN32
	/* from libdnet's intf-win32.c */
	extern "C" int g_has_npcap_loopback;
	#endif

	/* How long extra to wait before retransmitting for rate-limit detection */
	#define RLD_TIME_MS 1000

	int HssPredicate::operator() (const HostScanStats lhs, const HostScanStats rhs) const {
	const struct sockaddr_storage lss, rss;
	lss = (lhs) ? lhs->target->TargetSockAddr() : ss;
	rss = (rhs) ? rhs->target->TargetSockAddr() : ss;
	return 0 > sockaddr_storage_cmp(lss, rss);
	}
	struct sockaddr_storage *HssPredicate::ss = NULL;

	void UltraScanInfo::log_overall_rates(int logt) const {
	log_write(logt, "Overall sending rates: %.2f packets / s", send_rate_meter.getOverallPacketRate(&now));
	if (send_rate_meter.getNumBytes() > 0)
	log_write(logt, ", %.2f bytes / s", send_rate_meter.getOverallByteRate(&now));
	log_write(logt, ".\n");
	}

	void UltraScanInfo::log_current_rates(int logt, bool update) {
	log_write(logt, "Current sending rates: %.2f packets / s", send_rate_meter.getCurrentPacketRate(&now, update));
	if (send_rate_meter.getNumBytes() > 0)
	log_write(logt, ", %.2f bytes / s", send_rate_meter.getCurrentByteRate(&now));
	log_write(logt, ".\n");
	}

	void ultra_scan_performance_vars::init() {
	scan_performance_vars::init();
	ping_magnifier = 3;
	pingtime = 1250000;
	tryno_cap = o.getMaxRetransmissions();
	}

	const char *pspectype2ascii(int type) {
	switch (type) {
	case PS_NONE:
	return "NONE";
	case PS_TCP:
	return "TCP";
	case PS_UDP:
	return "UDP";
	case PS_SCTP:
	return "SCTP";
	case PS_PROTO:
	return "IP Proto";
	case PS_ICMP:
	return "ICMP";
	case PS_ARP:
	return "ARP";
	case PS_ICMPV6:
	return "ICMPv6";
	case PS_ND:
	return "ND";
	case PS_CONNECTTCP:
	return "connect";
	default:
	fatal("%s: Unknown type: %d", __func__, type);
	}
	return ""; // Unreached
	}

	/* Initialize the ultra_timing_vals structure timing. The utt must be
	TIMING_HOST or TIMING_GROUP. If you happen to have the current
	time handy, pass it as now, otherwise pass NULL */
	static void init_ultra_timing_vals(ultra_timing_vals *timing,
	enum ultra_timing_type utt,
	int num_hosts_in_group,
	struct ultra_scan_performance_vars *perf,
	struct timeval *now);

	/* Take a buffer, buf, of size bufsz (64 bytes is sufficient) and
	writes a short description of the probe (arg1) into buf. It also returns
	buf. */
	static char probespec2ascii(const probespec pspec, char *buf, unsigned int bufsz) {
	char flagbuf[32];
	char *f;
	switch (pspec->type) {
	case PS_TCP:
	if (!pspec->pd.tcp.flags) {
	Strncpy(flagbuf, "(none)", sizeof(flagbuf));
	} else {
	f = flagbuf;
	if (pspec->pd.tcp.flags & TH_SYN)
	*f++ = 'S';
	if (pspec->pd.tcp.flags & TH_FIN)
	*f++ = 'F';
	if (pspec->pd.tcp.flags & TH_RST)
	*f++ = 'R';
	if (pspec->pd.tcp.flags & TH_PUSH)
	*f++ = 'P';
	if (pspec->pd.tcp.flags & TH_ACK)
	*f++ = 'A';
	if (pspec->pd.tcp.flags & TH_URG)
	*f++ = 'U';
	if (pspec->pd.tcp.flags & TH_ECE)
	f++ = 'E'; / rfc 2481/3168 */
	if (pspec->pd.tcp.flags & TH_CWR)
	f++ = 'C'; / rfc 2481/3168 */
	*f++ = '\0';
	}
	Snprintf(buf, bufsz, "tcp to port %hu; flags: %s", pspec->pd.tcp.dport, flagbuf);
	break;
	case PS_UDP:
	Snprintf(buf, bufsz, "udp to port %hu", pspec->pd.udp.dport);
	break;
	case PS_SCTP:
	switch (pspec->pd.sctp.chunktype) {
	case SCTP_INIT:
	Strncpy(flagbuf, "INIT", sizeof(flagbuf));
	break;
	case SCTP_COOKIE_ECHO:
	Strncpy(flagbuf, "COOKIE-ECHO", sizeof(flagbuf));
	break;
	default:
	Strncpy(flagbuf, "(unknown)", sizeof(flagbuf));
	}
	Snprintf(buf, bufsz, "sctp to port %hu; chunk: %s", pspec->pd.sctp.dport,
	flagbuf);
	break;
	case PS_PROTO:
	Snprintf(buf, bufsz, "protocol %u", (unsigned int) pspec->proto);
	break;
	case PS_ICMP:
	Snprintf(buf, bufsz, "icmp type %d code %d",
	pspec->pd.icmp.type, pspec->pd.icmp.code);
	break;
	case PS_ARP:
	Snprintf(buf, bufsz, "ARP");
	break;
	case PS_ICMPV6:
	Snprintf(buf, bufsz, "icmpv6 type %d code %d",
	pspec->pd.icmpv6.type, pspec->pd.icmpv6.code);
	break;
	case PS_ND:
	Snprintf(buf, bufsz, "ND");
	break;
	case PS_CONNECTTCP:
	Snprintf(buf, bufsz, "connect to port %hu", pspec->pd.tcp.dport);
	break;
	default:
	fatal("Unexpected %s type encountered", __func__);
	break;
	}
	return buf;
	}

	UltraProbe::UltraProbe() {
	type = UP_UNSET;
	tryno.opaque = 0;
	timedout = false;
	retransmitted = false;
	mypspec.type = PS_NONE;
	memset(&sent, 0, sizeof(prevSent));
	memset(&prevSent, 0, sizeof(prevSent));
	}

	UltraProbe::~UltraProbe() {
	if (type == UP_CONNECT)
	delete probes.CP;
	}

	GroupScanStats::GroupScanStats(UltraScanInfo *UltraSI) {
	memset(&latestip, 0, sizeof(latestip));
	memset(&timeout, 0, sizeof(timeout));
	USI = UltraSI;
	init_ultra_timing_vals(&timing, TIMING_GROUP, USI->numIncompleteHosts(), &(USI->perf), &USI->now);
	initialize_timeout_info(&to);
	/* Default timout should be much lower for arp */
	if (USI->ping_scan_arp)
	to.timeout = MAX(o.minRttTimeout(), MIN(o.initialRttTimeout(), INITIAL_ARP_RTT_TIMEOUT)) * 1000;
	num_probes_active = 0;
	numtargets = USI->numIncompleteHosts(); // They are all incomplete at the beginning
	numprobes = USI->numProbesPerHost();

	if (USI->scantype == CONNECT_SCAN \|\| USI->ptech.connecttcpscan)
	CSI = new ConnectScanInfo;
	else CSI = NULL;
	probes_sent = probes_sent_at_last_wait = 0;
	lastping_sent = lastrcvd = USI->now;
	send_no_earlier_than = USI->now;
	send_no_later_than = USI->now;
	lastping_sent_numprobes = 0;
	pinghost = NULL;
	gettimeofday(&last_wait, NULL);
	num_hosts_timedout = 0;
	}

	GroupScanStats::~GroupScanStats() {
	delete CSI;
	}

	/* Called whenever a probe is sent to any host. Should only be called by
	HostScanStats::probeSent. */
	void GroupScanStats::probeSent(unsigned int nbytes) {
	USI->send_rate_meter.update(nbytes, &USI->now);

	/* Find a new scheduling interval for minimum- and maximum-rate sending.
	Recall that these have effect only when --min-rate or --max-rate is
	given. */

	if (o.max_packet_send_rate != 0.0)
	TIMEVAL_ADD(send_no_earlier_than, send_no_earlier_than,
	(time_t) (1000000.0 / o.max_packet_send_rate));
	/* Allow send_no_earlier_than to slip into the past. This allows the sending
	scheduler to catch up and make up for delays in other parts of the scan
	engine. If we were to update send_no_earlier_than to the present the
	sending rate could be much less than the maximum requested, even if the
	connection is capable of the maximum. */

	if (o.min_packet_send_rate != 0.0) {
	if (TIMEVAL_SUBTRACT(send_no_later_than, USI->now) > 0) {
	/* The next scheduled send is in the future. That means there's slack time
	during which the sending rate could drop. Pull the time back to the
	present to prevent that. */
	send_no_later_than = USI->now;
	}
	TIMEVAL_ADD(send_no_later_than, send_no_later_than,
	(time_t) (1000000.0 / o.min_packet_send_rate));
	}
	}

	/* Returns true if the GLOBAL system says that sending is OK.*/
	bool GroupScanStats::sendOK(struct timeval *when) const {
	int recentsends;

	/* In case it's not okay to send, arbitrarily say to check back in one
	second. */
	if (when)
	TIMEVAL_MSEC_ADD(*when, USI->now, 1000);

	if ((USI->scantype == CONNECT_SCAN \|\| USI->ptech.connecttcpscan)
	&& CSI->numSDs >= CSI->maxSocketsAllowed)
	return false;

	/* We need to stop sending if it has been a long time since
	the last listen call, at least for systems such as Windows that
	don't give us a proper pcap time. Also for connect scans, since
	we don't get an exact response time with them either. */
	recentsends = USI->gstats->probes_sent - USI->gstats->probes_sent_at_last_wait;
	if (recentsends > 0 &&
	(USI->scantype == CONNECT_SCAN \|\| USI->ptech.connecttcpscan \|\| !pcap_recv_timeval_valid())) {
	int to_ms = (int) MAX(to.srtt * .75 / 1000, 50);
	if (TIMEVAL_MSEC_SUBTRACT(USI->now, last_wait) > to_ms)
	return false;
	}

	/* Enforce a maximum scanning rate, if necessary. If it's too early to send,
	return false. If not, mark now as a good time to send and allow the
	congestion control to override it. */
	if (o.max_packet_send_rate != 0.0) {
	if (TIMEVAL_SUBTRACT(send_no_earlier_than, USI->now) > 0) {
	if (when)
	*when = send_no_earlier_than;
	return false;
	} else {
	if (when)
	*when = USI->now;
	}
	}

	/* Enforce a minimum scanning rate, if necessary. If we're ahead of schedule,
	record the time of the next scheduled send and submit to congestion
	control. If we're behind schedule, return true to indicate that we need to
	send right now. */
	if (o.min_packet_send_rate != 0.0) {
	if (TIMEVAL_SUBTRACT(send_no_later_than, USI->now) > 0) {
	if (when)
	*when = send_no_later_than;
	} else {
	if (when)
	*when = USI->now;
	return true;
	}
	}

	/* There are good arguments for limiting the number of probes sent
	between waits even when we do get appropriate receive times. For
	example, overflowing the pcap receive buffer with responses is no
	fun. On one of my Linux boxes, it seems to hold about 113
	responses when I scan localhost. And half of those are the @#$#
	sends being received. I think I'll put a limit of 50 sends per
	wait */
	if (recentsends >= 50)
	return false;

	/* In case the user specifically asked for no group congestion control */
	if (o.nogcc) {
	if (when)
	*when = USI->now;
	return true;
	}

	/* When there is only one target left, let the host congestion
	stuff deal with it. */
	if (USI->numIncompleteHostsLessThan(2)) {
	if (when)
	*when = USI->now;
	return true;
	}

	if (timing.cwnd >= num_probes_active + 0.5) {
	if (when)
	*when = USI->now;
	return true;
	}

	return false;
	}

	/* Return true if pingprobe is an appropriate ping probe for the currently
	running scan. Because ping probes persist between host discovery and port
	scanning stages, it's possible to have a ping probe that is not relevant for
	the scan type, or won't be caught by the pcap filters. Examples of
	inappropriate ping probes are an ARP ping for a TCP scan, or a raw SYN ping
	for a connect scan. */
	static bool pingprobe_is_appropriate(const UltraScanInfo *USI,
	const probespec *pingprobe) {
	switch (pingprobe->type) {
	case(PS_NONE):
	return true;
	case(PS_CONNECTTCP):
	return USI->scantype == CONNECT_SCAN \|\| (USI->ping_scan && USI->ptech.connecttcpscan);
	case(PS_TCP):
	case(PS_UDP):
	case(PS_SCTP):
	return (USI->tcp_scan && USI->scantype != CONNECT_SCAN) \|\|
	USI->udp_scan \|\|
	USI->sctp_scan \|\|
	(USI->ping_scan && (USI->ptech.rawtcpscan \|\| USI->ptech.rawudpscan \|\| USI->ptech.rawsctpscan));
	case(PS_PROTO):
	return USI->prot_scan \|\| (USI->ping_scan && USI->ptech.rawprotoscan);
	case(PS_ICMP):
	return ((USI->ping_scan && !USI->ping_scan_arp ) \|\| pingprobe->pd.icmp.type == 3);
	case(PS_ARP):
	return USI->ping_scan_arp;
	case(PS_ND):
	return USI->ping_scan_nd;
	}
	return false;
	}

	HostScanStats::HostScanStats(Target t, UltraScanInfo UltraSI) {
	target = t;
	USI = UltraSI;
	next_portidx = 0;
	sent_arp = false;
	next_ackportpingidx = 0;
	next_synportpingidx = 0;
	next_udpportpingidx = 0;
	next_sctpportpingidx = 0;
	next_protoportpingidx = 0;
	sent_icmp_ping = false;
	sent_icmp_mask = false;
	sent_icmp_ts = false;
	retry_capped_warned = false;
	num_probes_active = 0;
	num_probes_waiting_retransmit = 0;
	lastping_sent = lastprobe_sent = lastrcvd = USI->now;
	lastping_sent_numprobes = 0;
	nxtpseq = 1;
	max_successful_tryno = 0;
	ports_finished = 0;
	numprobes_sent = 0;
	memset(&completiontime, 0, sizeof(completiontime));
	init_ultra_timing_vals(&timing, TIMING_HOST, 1, &(USI->perf), &USI->now);
	bench_tryno = 0;
	memset(&sdn, 0, sizeof(sdn));
	sdn.last_boost = USI->now;
	sdn.delayms = o.scan_delay;
	rld.max_tryno_sent = 0;
	rld.rld_waiting = false;
	rld.rld_waittime = USI->now;
	if (!pingprobe_is_appropriate(USI, &target->pingprobe)) {
	if (o.debugging > 1)
	log_write(LOG_STDOUT, "%s pingprobe type %s is inappropriate for this scan type; resetting.\n", target->targetipstr(), pspectype2ascii(target->pingprobe.type));
	memset(&target->pingprobe, 0, sizeof(target->pingprobe));
	target->pingprobe_state = PORT_UNKNOWN;
	}
	}

	HostScanStats::~HostScanStats() {
	std::list<UltraProbe *>::iterator probeI, next;

	/* Move any hosts from the bench to probes_outstanding for easier deletion */
	for (probeI = probes_outstanding.begin(); probeI != probes_outstanding.end();
	probeI = next) {
	next = probeI;
	next++;
	destroyOutstandingProbe(probeI);
	}
	}

	/* Called whenever a probe is sent to this host. Takes care of updating scan
	delay and rate limiting variables. */
	void HostScanStats::probeSent(unsigned int nbytes) {
	lastprobe_sent = USI->now;

	/* Update group variables. */
	USI->gstats->probeSent(nbytes);
	}

	/* How long I am currently willing to wait for a probe response before
	considering it timed out. Uses the host values from target if they
	are available, otherwise from gstats. Results returned in
	MICROseconds. */
	unsigned long HostScanStats::probeTimeout() const {
	if (target->to.srtt > 0) {
	/* We have at least one timing value to use. Good enough, I suppose */
	return target->to.timeout;
	} else if (USI->gstats->to.srtt > 0) {
	/* OK, we'll use this one instead */
	return USI->gstats->to.timeout;
	} else {
	return target->to.timeout; /* It comes with a default */
	}
	}

	/* How long I'll wait until completely giving up on a probe.
	Timedout probes are often marked as such (and sometimes
	considered a drop), but kept in the list just in case they come
	really late. But after probeExpireTime(), I don't waste time
	keeping them around. Give in MICROseconds. The expiry time can
	depend on the type of probe. Pass NULL to get the default time. */
	unsigned long HostScanStats::probeExpireTime(const UltraProbe *probe) const {
	if (probe == NULL \|\| probe->type == UltraProbe::UP_CONNECT)
	/* timedout probes close socket -- late resp. impossible */
	return probeTimeout();
	else
	/* Wait a bit longer after probeTimeout. */
	return MIN(10000000, probeTimeout() * 10);
	}

	/* Returns OK if sending a new probe to this host is OK (to avoid
	flooding). If when is non-NULL, fills it with the time that sending
	will be OK assuming no pending probes are resolved by responses
	(call it again if they do). when will become now if it returns
	true. */
	bool HostScanStats::sendOK(struct timeval *when) const {
	struct ultra_timing_vals tmng;
	std::list<UltraProbe *>::const_iterator probeI;
	struct timeval probe_to, earliest_to, sendTime;
	long tdiff;

	if ((!USI->ping_scan && target->timedOut(&USI->now)) \|\| completed()) {
	if (when)
	*when = USI->now;
	return false;
	}

	/* If the group stats say we need to send a probe to enforce a minimum
	scanning rate, then we need to step up and send a probe. */
	if (o.min_packet_send_rate != 0.0) {
	if (TIMEVAL_SUBTRACT(USI->gstats->send_no_later_than, USI->now) <= 0) {
	if (when)
	*when = USI->now;
	return true;
	}
	}

	if (rld.rld_waiting) {
	if (TIMEVAL_AFTER(rld.rld_waittime, USI->now)) {
	if (when)
	*when = rld.rld_waittime;
	return false;
	} else {
	if (when)
	*when = USI->now;
	return true;
	}
	}

	if (sdn.delayms) {
	if (TIMEVAL_MSEC_SUBTRACT(USI->now, lastprobe_sent) < (int) sdn.delayms) {
	if (when) {
	TIMEVAL_MSEC_ADD(*when, lastprobe_sent, sdn.delayms);
	}
	return false;
	}
	}

	getTiming(&tmng);
	if (tmng.cwnd >= num_probes_active + .5 &&
	(freshPortsLeft() \|\| num_probes_waiting_retransmit \|\| !retry_stack.empty())) {
	if (when)
	*when = USI->now;
	return true;
	}

	if (!when)
	return false;

	TIMEVAL_MSEC_ADD(earliest_to, USI->now, 10000);

	// Any timeouts coming up?
	for (probeI = probes_outstanding.begin(); probeI != probes_outstanding.end();
	probeI++) {
	if (!(*probeI)->timedout) {
	TIMEVAL_MSEC_ADD(probe_to, (*probeI)->sent, probeTimeout() / 1000);
	if (TIMEVAL_SUBTRACT(probe_to, earliest_to) < 0) {
	earliest_to = probe_to;
	}
	}
	}

	// Will any scan delay affect this?
	if (sdn.delayms) {
	TIMEVAL_MSEC_ADD(sendTime, lastprobe_sent, sdn.delayms);
	if (TIMEVAL_BEFORE(sendTime, USI->now))
	sendTime = USI->now;
	tdiff = TIMEVAL_MSEC_SUBTRACT(earliest_to, sendTime);

	/* Timeouts previous to the sendTime requirement are pointless,
	and those later than sendTime are not needed if we can send a
	new packet at sendTime */
	if (tdiff < 0) {
	earliest_to = sendTime;
	} else {
	getTiming(&tmng);
	if (tdiff > 0 && tmng.cwnd > num_probes_active + .5) {
	earliest_to = sendTime;
	}
	}
	}

	*when = earliest_to;
	return false;
	}

	/* If there are pending probe timeouts, fills in when with the time of
	the earliest one and returns true. Otherwise returns false and
	puts now in when. */
	bool HostScanStats::nextTimeout(struct timeval *when) const {
	struct timeval probe_to, earliest_to;
	std::list<UltraProbe *>::const_iterator probeI;
	bool firstgood = true;

	assert(when);
	memset(&probe_to, 0, sizeof(probe_to));
	memset(&earliest_to, 0, sizeof(earliest_to));

	for (probeI = probes_outstanding.begin(); probeI != probes_outstanding.end();
	probeI++) {
	if (!(*probeI)->timedout) {
	TIMEVAL_ADD(probe_to, (*probeI)->sent, probeTimeout());
	if (firstgood \|\| TIMEVAL_SUBTRACT(probe_to, earliest_to) < 0) {
	earliest_to = probe_to;
	firstgood = false;
	}
	}
	}

	*when = (firstgood) ? USI->now : earliest_to;
	return !firstgood;
	}

	/* gives the maximum try number (try numbers start at zero and
	increments for each retransmission) that may be used, based on
	the scan type, observed network reliability, timing mode, etc.
	This may change during the scan based on network traffic. If
	capped is not null, it will be filled with true if the tryno is
	at its upper limit. That often calls for a warning to be issued,
	and marking of remaining timedout ports firewalled or whatever is
	appropriate. If mayincrease is non-NULL, it is set to whether
	the allowedTryno may increase again. If it is false, any probes
	which have reached the given limit may be dealt with. */
	unsigned int HostScanStats::allowedTryno(bool capped, bool mayincrease) const {
	std::list<UltraProbe *>::const_iterator probeI;
	UltraProbe *probe = NULL;
	bool allfinished = true;
	bool tryno_mayincrease = true;
	unsigned int maxval = 0;

	/* TODO: This should perhaps differ by scan type. */
	maxval = MAX(1, max_successful_tryno + 1);
	if (maxval > USI->perf.tryno_cap) {
	if (capped)
	*capped = true;
	maxval = USI->perf.tryno_cap;
	tryno_mayincrease = false; /* It never exceeds the cap */
	} else if (capped) *capped = false;

	/* Decide if the tryno can possibly increase. */
	if (tryno_mayincrease && num_probes_active == 0 && !freshPortsLeft()) {
	/* If every outstanding probe is timedout and at maxval, then no further
	retransmits are necessary. */
	for (probeI = probes_outstanding.begin();
	probeI != probes_outstanding.end(); probeI++) {
	probe = *probeI;
	assert(probe->timedout);
	if (!probe->retransmitted && !probe->isPing() && probe->get_tryno() < maxval) {
	/* Needs at least one more retransmit. */
	allfinished = false;
	break;
	}
	}
	if (allfinished)
	tryno_mayincrease = false;
	}

	if (mayincrease)
	*mayincrease = tryno_mayincrease;

	return maxval;
	}


	UltraScanInfo::UltraScanInfo() {
	}

	UltraScanInfo::~UltraScanInfo() {
	std::multiset<HostScanStats *, HssPredicate>::iterator hostI;

	for (hostI = incompleteHosts.begin(); hostI != incompleteHosts.end(); hostI++) {
	delete *hostI;
	}

	for (hostI = completedHosts.begin(); hostI != completedHosts.end(); hostI++) {
	delete *hostI;
	}

	incompleteHosts.clear();
	completedHosts.clear();

	delete gstats;
	delete SPM;
	if (rawsd >= 0) {
	close(rawsd);
	rawsd = -1;
	}
	if (pd) {
	pcap_close(pd);
	pd = NULL;
	}
	if (ethsd) {
	ethsd = NULL; /* NO need to eth_close it due to caching */
	}
	}

	/* Returns true if this scan is a "raw" scan. A raw scan is ont that requires a
	raw socket or ethernet handle to send, or a pcap sniffer to receive.
	Basically, any scan type except pure TCP connect scans are raw. */
	bool UltraScanInfo::isRawScan() const {
	return scantype != CONNECT_SCAN
	&& (tcp_scan \|\| udp_scan \|\| sctp_scan \|\| prot_scan \|\| ping_scan_arp \|\| ping_scan_nd
	\|\| (ping_scan && (ptech.rawicmpscan \|\| ptech.rawtcpscan \|\| ptech.rawudpscan
	\|\| ptech.rawsctpscan \|\| ptech.rawprotoscan)));
	}

	/* A circular buffer of the incompleteHosts. nextIncompleteHost() gives
	the next one. The first time it is called, it will give the
	first host in the list. If incompleteHosts is empty, returns
	NULL. */
	HostScanStats *UltraScanInfo::nextIncompleteHost() {
	HostScanStats *nxt;

	if (incompleteHosts.empty())
	return NULL;

	nxt = *nextI;
	nextI++;
	if (nextI == incompleteHosts.end())
	nextI = incompleteHosts.begin();

	return nxt;
	}

	/* Return a number between 0.0 and 1.0 inclusive indicating how much of the scan
	is done. */
	double UltraScanInfo::getCompletionFraction() const {
	std::multiset<HostScanStats *, HssPredicate>::const_iterator hostI;
	double total;

	/* Add 1 for each completed host. */
	total = gstats->numtargets - numIncompleteHosts();
	/* Get the completion fraction for each incomplete host. */
	for (hostI = incompleteHosts.begin(); hostI != incompleteHosts.end(); hostI++) {
	const HostScanStats host = hostI;
	int maxtries = host->allowedTryno(NULL, NULL) + 1;
	double thishostpercdone;

	// This is inexact (maxtries - 1) because numprobes_sent includes
	// at least one try of ports_finished.
	thishostpercdone = host->ports_finished * (maxtries - 1) + host->numprobes_sent;
	thishostpercdone /= maxtries * gstats->numprobes;
	if (thishostpercdone >= 0.9999)
	thishostpercdone = 0.9999;
	total += thishostpercdone;
	}

	return total / gstats->numtargets;
	}

	/* Initialize the state for ports that don't receive a response in all the
	targets. */
	static void set_default_port_state(std::vector<Target *> &targets, stype scantype) {
	std::vector<Target *>::iterator target;

	for (target = targets.begin(); target != targets.end(); target++) {
	switch (scantype) {
	case SYN_SCAN:
	case ACK_SCAN:
	case WINDOW_SCAN:
	case CONNECT_SCAN:
	(*target)->ports.setDefaultPortState(IPPROTO_TCP, PORT_FILTERED);
	break;
	case SCTP_INIT_SCAN:
	(*target)->ports.setDefaultPortState(IPPROTO_SCTP, PORT_FILTERED);
	break;
	case NULL_SCAN:
	case FIN_SCAN:
	case MAIMON_SCAN:
	case XMAS_SCAN:
	(*target)->ports.setDefaultPortState(IPPROTO_TCP, PORT_OPENFILTERED);
	break;
	case UDP_SCAN:
	(*target)->ports.setDefaultPortState(IPPROTO_UDP,
	o.defeat_icmp_ratelimit ? PORT_CLOSEDFILTERED : PORT_OPENFILTERED);
	break;
	case IPPROT_SCAN:
	(*target)->ports.setDefaultPortState(IPPROTO_IP, PORT_OPENFILTERED);
	break;
	case SCTP_COOKIE_ECHO_SCAN:
	(*target)->ports.setDefaultPortState(IPPROTO_SCTP, PORT_OPENFILTERED);
	break;
	case PING_SCAN:
	case PING_SCAN_ARP:
	case PING_SCAN_ND:
	break;
	default:
	fatal("Unexpected scan type found in %s()", __func__);
	}
	}
	}

	/* Order of initializations in this function CAN BE IMPORTANT, so be careful
	mucking with it. */
	void UltraScanInfo::Init(std::vector<Target > &Targets, const struct scan_lists pts, stype scantp) {
	unsigned int targetno = 0;
	HostScanStats *hss;
	int num_timedout = 0;

	gettimeofday(&now, NULL);

	ports = pts;

	seqmask = get_random_u32();
	scantype = scantp;
	SPM = new ScanProgressMeter(scantype2str(scantype));
	send_rate_meter.start(&now);
	tcp_scan = udp_scan = sctp_scan = prot_scan = false;
	ping_scan = noresp_open_scan = ping_scan_arp = ping_scan_nd = false;
	memset((char *) &ptech, 0, sizeof(ptech));
	perf.init();
	switch (scantype) {
	case FIN_SCAN:
	case XMAS_SCAN:
	case MAIMON_SCAN:
	case NULL_SCAN:
	noresp_open_scan = true;
	case ACK_SCAN:
	case CONNECT_SCAN:
	case SYN_SCAN:
	case WINDOW_SCAN:
	tcp_scan = true;
	break;
	case UDP_SCAN:
	noresp_open_scan = true;
	udp_scan = true;
	break;
	case SCTP_INIT_SCAN:
	case SCTP_COOKIE_ECHO_SCAN:
	sctp_scan = true;
	break;
	case IPPROT_SCAN:
	noresp_open_scan = true;
	prot_scan = true;
	break;
	case PING_SCAN:
	ping_scan = true;
	/* What kind of pings are we doing? */
	if (o.pingtype & (PINGTYPE_ICMP_PING \| PINGTYPE_ICMP_MASK \| PINGTYPE_ICMP_TS))
	ptech.rawicmpscan = 1;
	if (o.pingtype & PINGTYPE_UDP)
	ptech.rawudpscan = 1;
	if (o.pingtype & PINGTYPE_SCTP_INIT)
	ptech.rawsctpscan = 1;
	if (o.pingtype & PINGTYPE_TCP) {
	if (o.isr00t)
	ptech.rawtcpscan = 1;
	else
	ptech.connecttcpscan = 1;
	}
	if (o.pingtype & PINGTYPE_PROTO)
	ptech.rawprotoscan = 1;
	if (o.pingtype & PINGTYPE_CONNECTTCP)
	ptech.connecttcpscan = 1;
	break;
	case PING_SCAN_ARP:
	ping_scan = true;
	ping_scan_arp = true;
	/* For ARP and ND scan, we send pings more frequently. Otherwise we can't
	* notice drops until we start sending retransmits after RLD_TIME_MS. */
	perf.pingtime = RLD_TIME_MS * 1000 / 4;
	break;
	case PING_SCAN_ND:
	ping_scan = true;
	ping_scan_nd = true;
	perf.pingtime = RLD_TIME_MS * 1000 / 4;
	break;
	default:
	break;
	}

	set_default_port_state(Targets, scantype);

	/* Keep a completed host around for a standard TCP MSL (2 min) */
	completedHostLifetime = 120000;
	memset(&lastCompletedHostRemoval, 0, sizeof(lastCompletedHostRemoval));

	for (targetno = 0; targetno < Targets.size(); targetno++) {
	if (Targets[targetno]->timedOut(&now)) {
	num_timedout++;
	continue;
	}

	hss = new HostScanStats(Targets[targetno], this);
	incompleteHosts.insert(hss);
	}
	numInitialTargets = Targets.size();
	nextI = incompleteHosts.begin();

	gstats = new GroupScanStats(this); /* Peeks at several elements in USI - careful of order */
	gstats->num_hosts_timedout += num_timedout;

	pd = NULL;
	rawsd = -1;
	ethsd = NULL;

	/* See if we need an ethernet handle or raw socket. Basically, it's if we
	aren't doing a TCP connect scan, or if we're doing a ping scan that
	requires it. */
	if (isRawScan()) {
	if (ping_scan_arp \|\| (ping_scan_nd && o.sendpref != PACKET_SEND_IP_STRONG) \|\| ((o.sendpref & PACKET_SEND_ETH) &&
	(Targets[0]->ifType() == devt_ethernet
	#ifdef WIN32
	\|\| (g_has_npcap_loopback && Targets[0]->ifType() == devt_loopback)
	#endif
	))) {
	/* We'll send ethernet packets with dnet */
	ethsd = eth_open_cached(Targets[0]->deviceName());
	if (ethsd == NULL)
	fatal("dnet: Failed to open device %s", Targets[0]->deviceName());
	rawsd = -1;
	} else {
	#ifdef WIN32
	win32_fatal_raw_sockets(Targets[0]->deviceName());
	#endif
	rawsd = nmap_raw_socket();
	if (rawsd < 0)
	pfatal("Couldn't open a raw socket. "
	#if defined(sun) && defined(__SVR4)
	"In Solaris shared-IP non-global zones, this requires the PRIV_NET_RAWACCESS privilege. "
	#endif
	"Error"
	);
	/* We do not want to unblock the socket since we want to wait
	if kernel send buffers fill up rather than get ENOBUF, and
	we won't be receiving on the socket anyway
	unblock_socket(rawsd);*/
	ethsd = NULL;
	}
	}
	base_port = UltraScanInfo::increment_base_port();
	}

	/* Return the total number of probes that may be sent to each host. This never
	changes after initialization. */
	unsigned int UltraScanInfo::numProbesPerHost() const {
	unsigned int numprobes = 0;

	if (tcp_scan) {
	numprobes = ports->tcp_count;
	} else if (udp_scan) {
	numprobes = ports->udp_count;
	} else if (sctp_scan) {
	numprobes = ports->sctp_count;
	} else if (prot_scan) {
	numprobes = ports->prot_count;
	} else if (ping_scan_arp) {
	numprobes = 1;
	} else if (ping_scan_nd) {
	numprobes = 1;
	} else if (ping_scan) {
	numprobes = 0;
	if (ptech.rawtcpscan) {
	if (o.pingtype & PINGTYPE_TCP_USE_ACK)
	numprobes += ports->ack_ping_count;
	if (o.pingtype & PINGTYPE_TCP_USE_SYN)
	numprobes += ports->syn_ping_count;
	}
	if (ptech.rawudpscan)
	numprobes += ports->udp_ping_count;
	if (ptech.rawsctpscan)
	numprobes += ports->sctp_ping_count;
	if (ptech.rawicmpscan) {
	if (o.pingtype & PINGTYPE_ICMP_PING)
	numprobes++;
	if (o.pingtype & PINGTYPE_ICMP_MASK)
	numprobes++;
	if (o.pingtype & PINGTYPE_ICMP_TS)
	numprobes++;
	}
	if (ptech.rawprotoscan)
	numprobes += ports->proto_ping_count;
	if (ptech.connecttcpscan)
	numprobes += ports->syn_ping_count;
	} else assert(0);

	return numprobes;
	}

	/* Consults with the group stats, and the hstats for every
	incomplete hosts to determine whether any probes may be sent.
	Returns true if they can be sent immediately. If when is
	non-NULL, it is filled with the next possible time that probes
	can be sent, assuming no probe responses are received (call it
	again if they are). when will be now, if the function returns
	true */
	bool UltraScanInfo::sendOK(struct timeval *when) const {
	struct timeval lowhtime = {0};
	struct timeval tmptv;
	std::multiset<HostScanStats *, HssPredicate>::const_iterator host;
	bool ggood = false;
	bool thisHostGood = false;
	bool foundgood = false;

	ggood = gstats->sendOK(when);

	if (!ggood) {
	if (when) {
	lowhtime = *when;
	// Can't do anything until global is OK - means packet receipt
	// or probe timeout.
	for (host = incompleteHosts.begin(); host != incompleteHosts.end();
	host++) {
	if ((*host)->nextTimeout(&tmptv)) {
	if (TIMEVAL_SUBTRACT(tmptv, lowhtime) < 0)
	lowhtime = tmptv;
	}
	}
	*when = lowhtime;
	}
	} else {
	for (host = incompleteHosts.begin(); host != incompleteHosts.end(); host++) {
	thisHostGood = (*host)->sendOK(&tmptv);
	if (ggood && thisHostGood) {
	lowhtime = tmptv;
	foundgood = true;
	break;
	}

	if (!foundgood \|\| TIMEVAL_SUBTRACT(lowhtime, tmptv) > 0) {
	lowhtime = tmptv;
	foundgood = true;
	}
	}

	assert(foundgood);
	}

	/* Defer to the group stats if they need a shorter delay to enforce a minimum
	packet sending rate. */
	if (o.min_packet_send_rate != 0.0) {
	if (TIMEVAL_MSEC_SUBTRACT(gstats->send_no_later_than, lowhtime) < 0)
	lowhtime = gstats->send_no_later_than;
	}

	if (TIMEVAL_MSEC_SUBTRACT(lowhtime, now) < 0)
	lowhtime = now;

	if (when)
	*when = lowhtime;

	return (TIMEVAL_MSEC_SUBTRACT(lowhtime, now) == 0);
	}

	/* Find a HostScanStats by its IP address in the incomplete and completed lists.
	Returns NULL if none are found. */
	HostScanStats UltraScanInfo::findHost(struct sockaddr_storage ss) const {
	std::multiset<HostScanStats *, HssPredicate>::const_iterator hss;

	HssPredicate::ss = ss;
	HostScanStats *fakeHss = NULL;

	hss = incompleteHosts.find(fakeHss);
	if (hss != incompleteHosts.end()) {
	if (o.debugging > 2)
	log_write(LOG_STDOUT, "Found %s in incomplete hosts list.\n", (*hss)->target->targetipstr());
	return *hss;
	}

	hss = completedHosts.find(fakeHss);
	if (hss != completedHosts.end()) {
	if (o.debugging > 2)
	log_write(LOG_STDOUT, "Found %s in completed hosts list.\n", (*hss)->target->targetipstr());
	return *hss;
	}

	return NULL;
	}

	/* Check if incompleteHosts list contains less than n elements. This function
	is here to replace numIncompleteHosts() < n, which would have to walk
	through the entire list. */
	bool UltraScanInfo::numIncompleteHostsLessThan(unsigned int n) const {
	std::multiset<HostScanStats *, HssPredicate>::const_iterator hostI;
	unsigned int count;

	count = 0;
	hostI = incompleteHosts.begin();
	while (count < n && hostI != incompleteHosts.end()) {
	hostI++;
	count++;
	}

	return count < n;
	}

	static bool pingprobe_is_better(const probespec *new_probe, int new_state,
	const probespec *old_probe, int old_state);

	/* Removes any hosts that have completed their scans from the incompleteHosts
	list, and remove any hosts from completedHosts which have exceeded their
	lifetime. Returns the number of hosts removed. */
	int UltraScanInfo::removeCompletedHosts() {
	std::multiset<HostScanStats *, HssPredicate>::iterator hostI, nxt;
	HostScanStats *hss = NULL;
	int hostsRemoved = 0;
	bool timedout = false;
	struct timeval compare;

	/* We don't want to run this all of the time */
	TIMEVAL_MSEC_ADD(compare, lastCompletedHostRemoval, completedHostLifetime / 2);
	if (TIMEVAL_AFTER(now, compare) ) {
	for (hostI = completedHosts.begin(); hostI != completedHosts.end(); hostI = nxt) {
	nxt = hostI;
	nxt++;
	hss = (*hostI);

	/* Keep it if it's our port scan ping host */
	if (hss == gstats->pinghost)
	continue;

	TIMEVAL_MSEC_ADD(compare, hss->completiontime, completedHostLifetime);
	if (TIMEVAL_AFTER(now, compare) ) {
	/* Any active probes in completed hosts count against our global
	* cwnd, so be sure to remove them or we can run out of space. */
	hss->destroyAllOutstandingProbes();
	completedHosts.erase(hostI);
	hostsRemoved++;
	}
	}
	lastCompletedHostRemoval = now;
	}

	for (hostI = incompleteHosts.begin(); hostI != incompleteHosts.end();
	hostI = nxt) {
	nxt = hostI;
	nxt++;
	hss = *hostI;
	assert(hss);
	// Don't bother checking timedOut for discovery scans or if the target is already completed.
	if (hss->completed() \|\| (timedout = (!ping_scan) && hss->target->timedOut(&now)) != false) {
	/* A host to remove! First adjust nextI appropriately */
	if (nextI == hostI && incompleteHosts.size() > 1) {
	nextI++;
	if (nextI == incompleteHosts.end())
	nextI = incompleteHosts.begin();
	}
	if (o.verbose && gstats->numprobes > 50) {
	int remain = incompleteHosts.size() - 1;
	if (remain && !timedout)
	log_write(LOG_STDOUT, "Completed %s against %s in %.2fs (%d %s)\n",
	scantype2str(scantype), hss->target->targetipstr(),
	TIMEVAL_MSEC_SUBTRACT(now, SPM->begin) / 1000.0, remain,
	(remain == 1) ? "host left" : "hosts left");
	else if (timedout)
	log_write(LOG_STDOUT, "%s timed out during %s (%d %s)\n",
	hss->target->targetipstr(), scantype2str(scantype), remain,
	(remain == 1) ? "host left" : "hosts left");
	}
	if (o.debugging > 2) {
	unsigned int num_outstanding_probes;
	num_outstanding_probes = hss->num_probes_outstanding();
	log_write(LOG_PLAIN, "Moving %s to completed hosts list with %d outstanding %s.\n",
	hss->target->targetipstr(), num_outstanding_probes,
	num_outstanding_probes == 1 ? "probe" : "probes");
	if (o.debugging > 3) {
	char tmpbuf[64];
	std::list<UltraProbe *>::const_iterator iter;
	for (iter = hss->probes_outstanding.begin(); iter != hss->probes_outstanding.end(); iter++)
	log_write(LOG_PLAIN, "* %s\n", probespec2ascii((probespec ) (iter)->pspec(), tmpbuf, sizeof(tmpbuf)));
	}
	}
	hss->completiontime = now;
	completedHosts.insert(hss);
	incompleteHosts.erase(hostI);
	hostsRemoved++;
	/* Consider making this host the new global ping host during its
	retirement in the completed hosts list. */
	HostScanStats *pinghost = gstats->pinghost;
	if ((pinghost == NULL && hss->target->pingprobe.type != PS_NONE)
	\|\| (pinghost != NULL && pinghost->num_probes_active == 0
	&& !pingprobe_is_better(&pinghost->target->pingprobe, pinghost->target->pingprobe_state, &hss->target->pingprobe, hss->target->pingprobe_state))) {
	if (o.debugging > 1)
	log_write(LOG_PLAIN, "Changing global ping host to %s.\n", hss->target->targetipstr());
	gstats->pinghost = hss;
	}
	if (timedout)
	gstats->num_hosts_timedout++;
	/* We may have received an ARP response before we sent a probe, which
	* would mean the timeout clock is not running. Avoid an assertion
	* failure here by checking first. */
	if (hss->target->timeOutClockRunning()) {
	hss->target->stopTimeOutClock(&now);
	}
	}
	}
	return hostsRemoved;
	}

	/* Determines an ideal number of hosts to be scanned (port scan, os
	scan, version detection, etc.) in parallel after the ping scan is
	completed. This is a balance between efficiency (more hosts in
	parallel often reduces scan time per host) and results latency (you
	need to wait for all hosts to finish before Nmap can spit out the
	results). Memory consumption usually also increases with the
	number of hosts scanned in parallel, though rarely to significant
	levels. */
	int determineScanGroupSize(int hosts_scanned_so_far,
	const struct scan_lists *ports) {
	int groupsize = 16;

	if (o.UDPScan())
	groupsize = 128;
	else if (o.SCTPScan())
	groupsize = 128;
	else if (o.TCPScan()) {
	groupsize = MAX(1024 / (ports->tcp_count ? ports->tcp_count : 1), 64);
	if (ports->tcp_count > 1000 && o.timing_level <= 4) {
	int quickgroupsz = 4;
	if (o.timing_level == 4)
	quickgroupsz = 8;
	if (hosts_scanned_so_far == 0)
	groupsize = quickgroupsz; // Give quick results for the very first batch
	else if (hosts_scanned_so_far == quickgroupsz &&
	groupsize > quickgroupsz * 2)
	/* account for initial quick-scan to keep us aligned
	on common network boundaries (e.g. /24) */
	groupsize -= quickgroupsz;
	}
	}

	groupsize = box(o.minHostGroupSz(), o.maxHostGroupSz(), groupsize);

	if (o.max_ips_to_scan && (o.max_ips_to_scan - hosts_scanned_so_far) < (unsigned int)groupsize)
	// don't scan more randomly generated hosts than was specified
	groupsize = o.max_ips_to_scan - hosts_scanned_so_far;

	return groupsize;
	}

	/* Initialize the ultra_timing_vals structure timing. The utt must be
	TIMING_HOST or TIMING_GROUP. If you happen to have the current
	time handy, pass it as now, otherwise pass NULL */
	static void init_ultra_timing_vals(ultra_timing_vals *timing,
	enum ultra_timing_type utt,
	int num_hosts_in_group,
	struct ultra_scan_performance_vars *perf,
	struct timeval *now) {
	timing->cwnd = (utt == TIMING_HOST) ? perf->host_initial_cwnd : perf->group_initial_cwnd;
	timing->ssthresh = perf->initial_ssthresh; /* Will be reduced if any packets are dropped anyway */
	timing->num_replies_expected = 0;
	timing->num_replies_received = 0;
	timing->num_updates = 0;
	if (now)
	timing->last_drop = *now;
	else gettimeofday(&timing->last_drop, NULL);
	}

	/* Returns the next probe to try against target. Supports many
	different types of probes (see probespec structure). Returns 0 and
	fills in pspec if there is a new probe, -1 if there are none
	left. */
	static int get_next_target_probe(UltraScanInfo USI, HostScanStats hss,
	probespec *pspec) {
	assert(pspec);

	if (USI->tcp_scan) {
	if (hss->next_portidx >= USI->ports->tcp_count)
	return -1;
	if (USI->scantype == CONNECT_SCAN)
	pspec->type = PS_CONNECTTCP;
	else
	pspec->type = PS_TCP;
	pspec->proto = IPPROTO_TCP;

	pspec->pd.tcp.dport = USI->ports->tcp_ports[hss->next_portidx++];
	if (USI->scantype == CONNECT_SCAN)
	pspec->pd.tcp.flags = TH_SYN;
	else if (o.scanflags != -1)
	pspec->pd.tcp.flags = o.scanflags;
	else {
	switch (USI->scantype) {
	case SYN_SCAN:
	pspec->pd.tcp.flags = TH_SYN;
	break;
	case ACK_SCAN:
	pspec->pd.tcp.flags = TH_ACK;
	break;
	case XMAS_SCAN:
	pspec->pd.tcp.flags = TH_FIN \| TH_URG \| TH_PUSH;
	break;
	case NULL_SCAN:
	pspec->pd.tcp.flags = 0;
	break;
	case FIN_SCAN:
	pspec->pd.tcp.flags = TH_FIN;
	break;
	case MAIMON_SCAN:
	pspec->pd.tcp.flags = TH_FIN \| TH_ACK;
	break;
	case WINDOW_SCAN:
	pspec->pd.tcp.flags = TH_ACK;
	break;
	default:
	assert(0);
	break;
	}
	}
	return 0;
	} else if (USI->udp_scan) {
	if (hss->next_portidx >= USI->ports->udp_count)
	return -1;
	pspec->type = PS_UDP;
	pspec->proto = IPPROTO_UDP;
	pspec->pd.udp.dport = USI->ports->udp_ports[hss->next_portidx++];
	return 0;
	} else if (USI->sctp_scan) {
	if (hss->next_portidx >= USI->ports->sctp_count)
	return -1;
	pspec->type = PS_SCTP;
	pspec->proto = IPPROTO_SCTP;
	pspec->pd.sctp.dport = USI->ports->sctp_ports[hss->next_portidx++];
	switch (USI->scantype) {
	case SCTP_INIT_SCAN:
	pspec->pd.sctp.chunktype = SCTP_INIT;
	break;
	case SCTP_COOKIE_ECHO_SCAN:
	pspec->pd.sctp.chunktype = SCTP_COOKIE_ECHO;
	break;
	default:
	assert(0);
	}
	return 0;
	} else if (USI->prot_scan) {
	if (hss->next_portidx >= USI->ports->prot_count)
	return -1;
	pspec->type = PS_PROTO;
	pspec->proto = USI->ports->prots[hss->next_portidx++];
	return 0;
	} else if (USI->ping_scan_arp) {
	if (hss->sent_arp)
	return -1;
	pspec->type = PS_ARP;
	hss->sent_arp = true;
	return 0;
	} else if (USI->ping_scan_nd) {
	if (hss->sent_arp)
	return -1;
	pspec->type = PS_ND;
	hss->sent_arp = true;
	return 0;
	} else if (USI->ping_scan) {
	/* This is ordered to try probes of higher effectiveness first:
	-PE -PS -PA -PP -PU
	-PA is slightly better than -PS when combined with -PE, but give -PS an
	edge because it is less likely to be dropped by firewalls. */
	if (USI->ptech.rawicmpscan) {
	if (hss->target->af() == AF_INET6) {
	pspec->type = PS_ICMPV6;
	pspec->proto = IPPROTO_ICMPV6;
	if ((o.pingtype & PINGTYPE_ICMP_PING) && !hss->sent_icmp_ping) {
	hss->sent_icmp_ping = true;
	pspec->pd.icmp.type = ICMPV6_ECHO;
	pspec->pd.icmp.code = 0;
	return 0;
	}
	}
	pspec->type = PS_ICMP;
	pspec->proto = IPPROTO_ICMP;
	if ((o.pingtype & PINGTYPE_ICMP_PING) && !hss->sent_icmp_ping) {
	hss->sent_icmp_ping = true;
	pspec->pd.icmp.type = ICMP_ECHO;
	pspec->pd.icmp.code = 0;
	return 0;
	}
	}
	if (USI->ptech.rawtcpscan) {
	pspec->type = PS_TCP;
	pspec->proto = IPPROTO_TCP;
	if ((o.pingtype & PINGTYPE_TCP_USE_SYN)
	&& hss->next_synportpingidx < USI->ports->syn_ping_count) {
	pspec->pd.tcp.dport = USI->ports->syn_ping_ports[hss->next_synportpingidx++];
	pspec->pd.tcp.flags = TH_SYN;
	return 0;
	}
	if ((o.pingtype & PINGTYPE_TCP_USE_ACK)
	&& hss->next_ackportpingidx < USI->ports->ack_ping_count) {
	pspec->pd.tcp.dport = USI->ports->ack_ping_ports[hss->next_ackportpingidx++];
	pspec->pd.tcp.flags = TH_ACK;
	return 0;
	}
	}
	if (USI->ptech.rawicmpscan) {
	pspec->type = PS_ICMP;
	pspec->proto = IPPROTO_ICMP;
	if ((o.pingtype & PINGTYPE_ICMP_TS) && !hss->sent_icmp_ts) {
	hss->sent_icmp_ts = true;
	pspec->pd.icmp.type = ICMP_TSTAMP;
	pspec->pd.icmp.code = 0;
	return 0;
	}
	}
	if (USI->ptech.rawudpscan && hss->next_udpportpingidx < USI->ports->udp_ping_count) {
	pspec->type = PS_UDP;
	pspec->proto = IPPROTO_UDP;
	pspec->pd.udp.dport = USI->ports->udp_ping_ports[hss->next_udpportpingidx++];
	return 0;
	}
	if (USI->ptech.rawsctpscan && hss->next_sctpportpingidx < USI->ports->sctp_ping_count) {
	pspec->type = PS_SCTP;
	pspec->proto = IPPROTO_SCTP;
	pspec->pd.sctp.dport = USI->ports->sctp_ping_ports[hss->next_sctpportpingidx++];
	pspec->pd.sctp.chunktype = SCTP_INIT;
	return 0;
	}
	if (USI->ptech.rawprotoscan && hss->next_protoportpingidx < USI->ports->proto_ping_count) {
	pspec->type = PS_PROTO;
	pspec->proto = USI->ports->proto_ping_ports[hss->next_protoportpingidx++];
	return 0;
	}
	if (USI->ptech.connecttcpscan && hss->next_synportpingidx < USI->ports->syn_ping_count) {
	pspec->type = PS_CONNECTTCP;
	pspec->proto = IPPROTO_TCP;
	pspec->pd.tcp.dport = USI->ports->syn_ping_ports[hss->next_synportpingidx++];
	pspec->pd.tcp.flags = TH_SYN;
	return 0;
	}
	if (USI->ptech.rawicmpscan) {
	pspec->type = PS_ICMP;
	pspec->proto = IPPROTO_ICMP;
	if ((o.pingtype & PINGTYPE_ICMP_MASK) && !hss->sent_icmp_mask) {
	hss->sent_icmp_mask = true;
	pspec->pd.icmp.type = ICMP_MASK;
	pspec->pd.icmp.code = 0;
	return 0;
	}
	}
	}
	assert(0); /* TODO: need to handle other protocols */
	return -1;
	}

	/* Returns whether there are ports remaining to probe */
	bool HostScanStats::freshPortsLeft() const {
	if (USI->tcp_scan) {
	return (next_portidx < USI->ports->tcp_count);
	} else if (USI->udp_scan) {
	return (next_portidx < USI->ports->udp_count);
	} else if (USI->sctp_scan) {
	return (next_portidx < USI->ports->sctp_count);
	} else if (USI->prot_scan) {
	return (next_portidx < USI->ports->prot_count);
	} else if (USI->ping_scan_arp \|\| USI->ping_scan_nd) {
	return !sent_arp;
	} else if (USI->ping_scan) {
	if (USI->ptech.rawtcpscan) {
	if (o.pingtype & PINGTYPE_TCP_USE_ACK && next_ackportpingidx < USI->ports->ack_ping_count)
	return true;
	if (o.pingtype & PINGTYPE_TCP_USE_SYN && next_synportpingidx < USI->ports->syn_ping_count)
	return true;
	}
	if (USI->ptech.rawicmpscan) {
	if ((o.pingtype & PINGTYPE_ICMP_PING) && !sent_icmp_ping)
	return true;
	if ((o.pingtype & PINGTYPE_ICMP_MASK) && !sent_icmp_mask)
	return true;
	if ((o.pingtype & PINGTYPE_ICMP_TS) && !sent_icmp_ts)
	return true;
	}
	if (USI->ptech.connecttcpscan && next_synportpingidx < USI->ports->syn_ping_count)
	return true;
	if (USI->ptech.rawudpscan && next_udpportpingidx < USI->ports->udp_ping_count)
	return true;
	if (USI->ptech.rawsctpscan && next_sctpportpingidx < USI->ports->sctp_ping_count)
	return true;
	if (USI->ptech.rawprotoscan && next_protoportpingidx < USI->ports->proto_ping_count)
	return true;
	return false;
	}
	assert(0);
	return false;
	}

	/* Returns the number of ports remaining to probe */
	int HostScanStats::numFreshPortsLeft() const {
	if (USI->tcp_scan) {
	if (next_portidx >= USI->ports->tcp_count)
	return 0;
	return USI->ports->tcp_count - next_portidx;
	} else if (USI->udp_scan) {
	if (next_portidx >= USI->ports->udp_count)
	return 0;
	return USI->ports->udp_count - next_portidx;
	} else if (USI->sctp_scan) {
	if (next_portidx >= USI->ports->sctp_count)
	return 0;
	return USI->ports->sctp_count - next_portidx;
	} else if (USI->prot_scan) {
	if (next_portidx >= USI->ports->prot_count)
	return 0;
	return USI->ports->prot_count - next_portidx;
	} else if (USI->ping_scan_arp) {
	if (sent_arp)
	return 0;
	return 1;
	} else if (USI->ping_scan_nd) {
	if (sent_arp)
	return 0;
	return 1;
	} else if (USI->ping_scan) {
	unsigned int num_probes = 0;
	if (USI->ptech.rawtcpscan) {
	if (o.pingtype & PINGTYPE_TCP_USE_ACK)
	num_probes += USI->ports->ack_ping_count - next_ackportpingidx;
	if (o.pingtype & PINGTYPE_TCP_USE_SYN)
	num_probes += USI->ports->syn_ping_count - next_synportpingidx;
	}
	if (USI->ptech.rawudpscan)
	num_probes += USI->ports->udp_ping_count - next_udpportpingidx;
	if (USI->ptech.rawsctpscan)
	num_probes += USI->ports->sctp_ping_count - next_sctpportpingidx;
	if (USI->ptech.rawicmpscan) {
	if ((o.pingtype & PINGTYPE_ICMP_PING) && !sent_icmp_ping)
	num_probes++;
	if ((o.pingtype & PINGTYPE_ICMP_MASK) && !sent_icmp_mask)
	num_probes++;
	if ((o.pingtype & PINGTYPE_ICMP_TS) && !sent_icmp_ts)
	num_probes++;
	}
	if (USI->ptech.rawprotoscan)
	num_probes += USI->ports->proto_ping_count - next_protoportpingidx;
	if (USI->ptech.connecttcpscan)
	num_probes += USI->ports->syn_ping_count - next_synportpingidx;
	return num_probes;
	}
	assert(0);
	return 0;
	}

	/* Removes a probe from probes_outstanding, adjusts HSS and USS
	active probe stats accordingly, then deletes the probe. */
	void HostScanStats::destroyOutstandingProbe(std::list<UltraProbe *>::iterator probeI) {
	UltraProbe probe = probeI;
	assert(!probes_outstanding.empty());
	if (!probe->timedout) {
	assert(num_probes_active > 0);
	num_probes_active--;
	assert(USI->gstats->num_probes_active > 0);
	USI->gstats->num_probes_active--;
	}

	if (!probe->isPing() && probe->timedout && !probe->retransmitted) {
	assert(num_probes_waiting_retransmit > 0);
	num_probes_waiting_retransmit--;
	}

	/* Remove it from scan watch lists, if it exists on them. */
	if (probe->type == UltraProbe::UP_CONNECT && probe->CP()->sd > 0)
	USI->gstats->CSI->clearSD(probe->CP()->sd);

	probes_outstanding.erase(probeI);
	delete probe;
	}

	/* Removes all probes from probes_outstanding using
	destroyOutstandingProbe. This is used in ping scan to quit waiting
	for responses once a host is known to be up. Invalidates iterators
	pointing into probes_outstanding. */
	void HostScanStats::destroyAllOutstandingProbes() {
	while (!probes_outstanding.empty())
	destroyOutstandingProbe(probes_outstanding.begin());
	}

	/* Adjust host and group timeouts (struct timeout_info) based on a received
	packet. If rcvdtime is NULL, nothing is updated.

	This function is called for every probe response received, in order to keep
	an accurate timeout estimate. ultrascan_adjust_timing, on the other hand, is
	not called when a response is not useful for adjusting other timing
	variables. */
	static void ultrascan_adjust_timeouts(UltraScanInfo USI, HostScanStats hss,
	UltraProbe *probe,
	struct timeval *rcvdtime) {
	if (rcvdtime == NULL)
	return;

	adjust_timeouts2(&(probe->sent), rcvdtime, &(hss->target->to));
	adjust_timeouts2(&(probe->sent), rcvdtime, &(USI->gstats->to));

	USI->gstats->lastrcvd = hss->lastrcvd = *rcvdtime;
	}

	/* Adjust host and group congestion control variables (struct ultra_timing_vals)
	and host send delay (struct send_delay_nfo) based on a received packet. Use
	rcvdtime == NULL to indicate that you have given up on a probe and want to
	count this as a DROPPED PACKET. */
	static void ultrascan_adjust_timing(UltraScanInfo USI, HostScanStats hss,
	UltraProbe *probe,
	struct timeval *rcvdtime) {
	int ping_magnifier = (probe->isPing()) ? USI->perf.ping_magnifier : 1;

	USI->gstats->timing.num_replies_expected++;
	USI->gstats->timing.num_updates++;

	hss->timing.num_replies_expected++;
	hss->timing.num_updates++;

	/* Notice a drop if
	1) We get a response to a retransmitted probe (meaning the first reply was
	dropped), or
	2) We got no response to a timing ping. */
	bool is_drop = (!probe->isPing() && probe->get_tryno() > 0 && rcvdtime != NULL)
	\|\| (probe->isPing() && rcvdtime == NULL);
	if (is_drop) {
	if (o.debugging > 1)
	log_write(LOG_PLAIN, "Ultrascan DROPPED %sprobe packet to %s detected\n", probe->isPing() ? "PING " : "", hss->target->targetipstr());
	// Drops often come in big batches, but we only want one decrease per batch.
	if (TIMEVAL_AFTER(probe->sent, hss->timing.last_drop))
	hss->timing.drop(hss->num_probes_active, &USI->perf, &USI->now);
	if (TIMEVAL_AFTER(probe->sent, USI->gstats->timing.last_drop))
	USI->gstats->timing.drop_group(USI->gstats->num_probes_active, &USI->perf, &USI->now);
	}
	/* If !probe->isPing() and rcvdtime == NULL, do nothing. */

	/* Increase the window for a positive reply. This can overlap with case (1)
	above. */
	if (rcvdtime != NULL) {
	USI->gstats->timing.ack(&USI->perf, ping_magnifier);
	hss->timing.ack(&USI->perf, ping_magnifier);
	}

	/* If packet drops are particularly bad, enforce a delay between
	packet sends (useful for cases such as UDP scan where responses
	are frequently rate limited by dest machines or firewalls) */

	/* First we decide whether this packet counts as a drop for send
	delay calculation purposes. This statement means if (a ping since last boost failed, or the previous packet was both sent after the last boost and dropped) */
	if (is_drop && TIMEVAL_AFTER(probe->sent, hss->sdn.last_boost)) {
	hss->sdn.droppedRespSinceDelayChanged++;
	// printf("SDELAY: increasing drops to %d (good: %d; tryno: %d, sent: %.4fs; prevSent: %.4fs, last_boost: %.4fs\n", hss->sdn.droppedRespSinceDelayChanged, hss->sdn.goodRespSinceDelayChanged, probe->tryno, o.TimeSinceStartMS(&probe->sent) / 1000.0, o.TimeSinceStartMS(&probe->prevSent) / 1000.0, o.TimeSinceStartMS(&hss->sdn.last_boost) / 1000.0);
	} else if (rcvdtime) {
	hss->sdn.goodRespSinceDelayChanged++;
	// printf("SDELAY: increasing good to %d (bad: %d)\n", hss->sdn.goodRespSinceDelayChanged, hss->sdn.droppedRespSinceDelayChanged);
	}

	/* Now change the send delay if necessary */
	unsigned int oldgood = hss->sdn.goodRespSinceDelayChanged;
	unsigned int oldbad = hss->sdn.droppedRespSinceDelayChanged;
	double threshold = (o.timing_level >= 4) ? 0.40 : 0.30;
	if (oldbad > 10 && (oldbad / ((double) oldbad + oldgood) > threshold)) {
	unsigned int olddelay = hss->sdn.delayms;
	hss->boostScanDelay();
	if (o.verbose && hss->sdn.delayms != olddelay)
	log_write(LOG_PLAIN, "Increasing send delay for %s from %d to %d due to %d out of %d dropped probes since last increase.\n",
	hss->target->targetipstr(), olddelay, hss->sdn.delayms, oldbad,
	oldbad + oldgood);
	}
	}

	/* Mark an outstanding probe as timedout. Adjusts stats
	accordingly. For connect scans, this closes the socket. */
	void HostScanStats::markProbeTimedout(std::list<UltraProbe *>::iterator probeI) {
	UltraProbe probe = probeI;
	assert(!probe->timedout);
	assert(!probe->retransmitted);
	probe->timedout = true;
	assert(num_probes_active > 0);
	num_probes_active--;
	assert(USI->gstats->num_probes_active > 0);
	USI->gstats->num_probes_active--;
	ultrascan_adjust_timing(USI, this, probe, NULL);
	if (!probe->isPing())
	/* I'll leave it in the queue in case some response ever does come */
	num_probes_waiting_retransmit++;

	if (probe->type == UltraProbe::UP_CONNECT && probe->CP()->sd >= 0 ) {
	/* Free the socket as that is a valuable resource, though it is a shame
	late responses will not be permitted */
	USI->gstats->CSI->clearSD(probe->CP()->sd);
	close(probe->CP()->sd);
	probe->CP()->sd = -1;
	}
	}

	bool HostScanStats::completed() const {
	/* If there are probes active or awaiting retransmission, we are not done. */
	if (num_probes_active != 0 \|\| num_probes_waiting_retransmit != 0
	\|\| !probe_bench.empty() \|\| !retry_stack.empty()) {
	return false;
	}

	/* With ping scan, we are done once we know the host is up or down. */
	if (USI->ping_scan && ((target->flags & HOST_UP)
	\|\| (target->flags & HOST_DOWN) \|\| target->weird_responses)) {
	return true;
	}

	/* With other types of scan, we are done when there are no more ports to
	probe. */
	return !freshPortsLeft();
	}

	/* This function provides the proper cwnd and ssthresh to use. It may
	differ from versions in timing member var because when no responses
	have been received for this host, may look at others in the group.
	For CHANGING this host's timing, use the timing memberval
	instead. */
	void HostScanStats::getTiming(struct ultra_timing_vals *tmng) const {
	assert(tmng);

	/* Use the per-host value if a pingport has been found or very few probes
	have been sent */
	if (target->pingprobe.type != PS_NONE \|\| numprobes_sent < 80) {
	*tmng = timing;
	return;
	}

	/* Otherwise, use the global cwnd stats if it has sufficient responses */
	if (USI->gstats->timing.num_updates > 1) {
	*tmng = USI->gstats->timing;
	return;
	}

	/* Last resort is to use canned values */
	tmng->cwnd = USI->perf.host_initial_cwnd;
	tmng->ssthresh = USI->perf.initial_ssthresh;
	tmng->num_updates = 0;
	return;
	}

	/* Define a score for a ping probe, for the purposes of deciding whether one
	probe should be preferred to another. The order, from most preferred to least
	preferred, is
	Raw TCP/SCTP (not filtered, not SYN/INIT to an open port)
	ICMP information queries (echo request, timestamp request, netmask req)
	ARP/ND
	Raw TCP/SCTP (SYN/INIT to an open port)
	UDP, IP protocol, or other ICMP (including filtered TCP/SCTP)
	TCP connect
	Anything else
	Raw TCP SYN / SCTP INIT to an open port is given a low preference because of the
	risk of SYN flooding (this is the only case where the port state is considered).
	The probe passed to this function is assumed to have received a positive
	response, that is, it should not have set a port state just by timing out. */
	static unsigned int pingprobe_score(const probespec *pspec, int state) {
	unsigned int score;

	switch (pspec->type) {
	case PS_TCP:
	if (state == PORT_FILTERED) /* Received an ICMP error. */
	score = 20;
	else if (pspec->pd.tcp.flags == TH_SYN && (state == PORT_OPEN \|\| state == PORT_UNKNOWN))
	score = 30;
	else if (pspec->pd.tcp.dport == 25 \|\|
	pspec->pd.tcp.dport == 113 \|\|
	pspec->pd.tcp.dport == 135 \|\|
	pspec->pd.tcp.dport == 139 \|\|
	pspec->pd.tcp.dport == 445)
	/* Frequently spoofed port numbers */
	score = 50;
	else
	score = 60;
	break;
	case PS_SCTP:
	if (state == PORT_FILTERED) /* Received an ICMP error. */
	score = 20;
	else if (state == PORT_OPEN \|\| state == PORT_UNKNOWN)
	score = 30;
	else
	score = 60;
	break;
	case PS_ICMP:
	if (pspec->pd.icmp.type == ICMP_ECHO \|\| pspec->pd.icmp.type == ICMP_MASK \|\| pspec->pd.icmp.type == ICMP_TSTAMP)
	score = 50;
	else
	score = 20;
	break;
	case PS_ARP:
	case PS_ND:
	score = 40;
	break;
	case PS_UDP:
	// Penalize ports with many payloads, since we can't be sure which one responded.
	score = 20 - udp_payload_count(pspec->pd.udp.dport);
	// But one payload is ok
	if (score == 19)
	score = 20;
	break;
	case PS_PROTO:
	score = 20;
	break;
	case PS_CONNECTTCP:
	score = 10;
	break;
	case PS_NONE:
	default:
	score = 0;
	break;
	}

	return score;
	}

	/* Return true if new_probe and new_state define a better ping probe, as defined
	by pingprobe_score, than do old_probe and old_state. */
	static bool pingprobe_is_better(const probespec *new_probe, int new_state,
	const probespec *old_probe, int old_state) {
	return pingprobe_score(new_probe, new_state) > pingprobe_score(old_probe, old_state);
	}

	static bool ultrascan_host_pspec_update(UltraScanInfo USI, HostScanStats hss,
	const probespec *pspec, int newstate);

	/* Like ultrascan_port_probe_update(), except it is called with just a
	probespec rather than a whole UltraProbe. Returns true if the port
	was added or at least the state was changed. */
	static bool ultrascan_port_pspec_update(UltraScanInfo *USI,
	HostScanStats *hss,
	const probespec *pspec,
	int newstate) {
	u16 portno = 0;
	u8 proto = 0;
	int oldstate = PORT_TESTING;
	/* Whether no response means a port is open */
	bool noresp_open_scan = USI->noresp_open_scan;

	if (USI->prot_scan) {
	proto = IPPROTO_IP;
	portno = pspec->proto;
	} else if (pspec->type == PS_TCP \|\| pspec->type == PS_CONNECTTCP) {
	proto = IPPROTO_TCP;
	portno = pspec->pd.tcp.dport;
	} else if (pspec->type == PS_UDP) {
	proto = IPPROTO_UDP;
	portno = pspec->pd.udp.dport;
	} else if (pspec->type == PS_SCTP) {
	proto = IPPROTO_SCTP;
	portno = pspec->pd.sctp.dport;
	} else assert(0);

	if (hss->target->ports.portIsDefault(portno, proto)) {
	oldstate = PORT_TESTING;
	hss->ports_finished++;
	} else {
	oldstate = hss->target->ports.getPortState(portno, proto);
	}

	/* printf("TCP port %hu has changed from state %s to %s!\n", portno, statenum2str(oldstate), statenum2str(newstate)); */
	switch (oldstate) {
	/* TODO: I need more code here to determine when a state should
	be overridden, for example PORT_OPEN trumps PORT_FILTERED
	in a SYN scan, but not necessarily for UDP scan */
	case PORT_TESTING:
	/* Brand new port -- add it to the list */
	hss->target->ports.setPortState(portno, proto, newstate);
	break;
	case PORT_OPEN:
	if (newstate != PORT_OPEN) {
	if (noresp_open_scan) {
	hss->target->ports.setPortState(portno, proto, newstate);
	} /* Otherwise The old open takes precedence */
	}
	break;
	case PORT_CLOSED:
	if (newstate != PORT_CLOSED) {
	if (!noresp_open_scan && newstate != PORT_FILTERED)
	hss->target->ports.setPortState(portno, proto, newstate);
	}
	break;
	case PORT_FILTERED:
	if (newstate != PORT_FILTERED) {
	if (!noresp_open_scan \|\| newstate != PORT_OPEN)
	hss->target->ports.setPortState(portno, proto, newstate);
	}
	break;
	case PORT_UNFILTERED:
	/* This could happen in an ACK scan if I receive a RST and then an
	ICMP filtered message. I'm gonna stick with unfiltered in that
	case. I'll change it if the new state is open or closed,
	though I don't expect that to ever happen */
	if (newstate == PORT_OPEN \|\| newstate == PORT_CLOSED)
	hss->target->ports.setPortState(portno, proto, newstate);
	break;
	case PORT_OPENFILTERED:
	if (newstate != PORT_OPENFILTERED) {
	hss->target->ports.setPortState(portno, proto, newstate);
	}
	break;
	default:
	fatal("Unexpected port state: %d\n", oldstate);
	break;
	}

	return oldstate != newstate;
	}

	/* Boost the scan delay for this host, usually because too many packet
	drops were detected. */
	void HostScanStats::boostScanDelay() {
	unsigned int maxAllowed = USI->tcp_scan ? o.maxTCPScanDelay() :
	USI->udp_scan ? o.maxUDPScanDelay() :
	o.maxSCTPScanDelay();
	if (sdn.delayms == 0)
	sdn.delayms = (USI->udp_scan) ? 50 : 5; // In many cases, a pcap wait takes a minimum of 80ms, so this matters little :(
	else sdn.delayms = MIN(sdn.delayms * 2, MAX(sdn.delayms, 1000));
	sdn.delayms = MIN(sdn.delayms, maxAllowed);
	sdn.last_boost = USI->now;
	sdn.droppedRespSinceDelayChanged = 0;
	sdn.goodRespSinceDelayChanged = 0;
	}

	/* Dismiss all probe attempts on bench -- hosts are marked down and ports will
	be set to whatever the default port state is for the scan. */
	void HostScanStats::dismissBench() {
	if (probe_bench.empty())
	return;
	while (!probe_bench.empty()) {
	if (USI->ping_scan)
	ultrascan_host_pspec_update(USI, this, &probe_bench.back(), HOST_DOWN);
	/* Nothing to do if !USI->ping_scan. ultrascan_port_pspec_update would
	allocate a Port object but we rely on the default port state to save
	memory. */
	probe_bench.pop_back();
	}
	bench_tryno = 0;
	}

	/* Move all members of bench to retry_stack for probe retransmission */
	void HostScanStats::retransmitBench() {
	if (probe_bench.empty())
	return;

	/* Move all contents of probe_bench to the end of retry_stack, updating retry_stack_tries accordingly */
	retry_stack.insert(retry_stack.end(), probe_bench.begin(), probe_bench.end());
	retry_stack_tries.insert(retry_stack_tries.end(), probe_bench.size(),
	bench_tryno);
	assert(retry_stack.size() == retry_stack_tries.size());
	probe_bench.erase(probe_bench.begin(), probe_bench.end());
	bench_tryno = 0;
	}

	/* Moves the given probe from the probes_outstanding list, to
	probe_bench, and decrements num_probes_waiting_retransmit
	accordingly */
	void HostScanStats::moveProbeToBench(std::list<UltraProbe *>::iterator probeI) {
	UltraProbe probe = probeI;
	if (!probe_bench.empty())
	assert(bench_tryno == probe->get_tryno());
	else {
	bench_tryno = probe->get_tryno();
	probe_bench.reserve(128);
	}
	probe_bench.push_back(*probe->pspec());
	probes_outstanding.erase(probeI);
	num_probes_waiting_retransmit--;
	delete probe;
	}

	/* Called when a ping response is discovered. If adjust_timing is false, timing
	stats are not updated. */
	void ultrascan_ping_update(UltraScanInfo USI, HostScanStats hss,
	std::list<UltraProbe *>::iterator probeI,
	struct timeval *rcvdtime,
	bool adjust_timing) {
	ultrascan_adjust_timeouts(USI, hss, *probeI, rcvdtime);
	if (adjust_timing)
	ultrascan_adjust_timing(USI, hss, *probeI, rcvdtime);
	hss->destroyOutstandingProbe(probeI);
	}

	static const char *readhoststate(int state) {
	switch (state) {
	case HOST_UNKNOWN:
	return "UNKNOWN";
	case HOST_UP:
	return "HOST_UP";
	case HOST_DOWN:
	return "HOST_DOWN";
	default:
	return "COMBO";
	}

	return NULL;
	}

	/* Update state of the host in hss based on its current state and newstate.
	Returns true if the state was changed. */
	static bool ultrascan_host_pspec_update(UltraScanInfo USI, HostScanStats hss,
	const probespec *pspec, int newstate) {
	int oldstate = hss->target->flags;
	/* If the host is already up, ignore any further updates. */
	if (hss->target->flags != HOST_UP) {
	// don't allow HOST_UNKNOWN to override a known state.
	hss->target->flags = (newstate == HOST_UNKNOWN ? oldstate : newstate);
	/* For port scans (not -sn) where output may be delayed until more scan
	* phases are done, emit a hosthint element during host discovery when a
	* target is found to be up. */
	if (oldstate != newstate && newstate == HOST_UP &&
	!o.noportscan && USI->ping_scan) {
	write_xml_hosthint(hss->target);
	}
	}
	return hss->target->flags != oldstate;
	}

	static void ultrascan_host_timeout_init(UltraScanInfo USI, HostScanStats hss) {
	// Don't count host discovery time against host timeout clock. For large
	// numbers of targets, we might be busy sending lots of new probes to new
	// targets, and that time shouldn't count against the individual target.
	if (!USI->ping_scan && !hss->target->timeOutClockRunning() && !hss->target->timedOut(NULL)) {
	if (o.debugging > 2) {
	log_write(LOG_STDOUT, "Ultrascan timeout init for %s at %.6f\n", hss->target->targetipstr(), TIMEVAL_SECS(USI->now));
	}
	hss->target->startTimeOutClock(&USI->now);
	}
	}

	/* Called when a new status is determined for host in hss (eg. it is
	found to be up or down by a ping/ping_arp scan. The probe that led
	to this new decision is in probeI. This function needs to update
	timing information and other stats as appropriate. If
	adjust_timing_hint is false, packet stats are not updated. */
	void ultrascan_host_probe_update(UltraScanInfo USI, HostScanStats hss,
	std::list<UltraProbe *>::iterator probeI,
	int newstate, struct timeval *rcvdtime,
	bool adjust_timing_hint) {
	UltraProbe probe = probeI;

	if (o.debugging > 1) {
	struct timeval tv;

	gettimeofday(&tv, NULL);
	log_write(LOG_STDOUT, "%s called for machine %s state %s -> %s (trynum %d time: %ld)\n", __func__, hss->target->targetipstr(), readhoststate(hss->target->flags), readhoststate(newstate), probe->get_tryno(), (long) TIMEVAL_SUBTRACT(tv, probe->sent));
	}

	ultrascan_host_pspec_update(USI, hss, probe->pspec(), newstate);

	ultrascan_adjust_timeouts(USI, hss, probe, rcvdtime);

	/* Decide whether to adjust timing. We and together a bunch of conditions.
	First, don't adjust timing if adjust_timing_hint is false. */
	bool adjust_timing = adjust_timing_hint;
	bool adjust_ping = adjust_timing_hint;

	/* If we got a response that meant "down" or "unknown", then it was an ICMP error. These
	are often rate-limited (RFC 1812) or generated by a different host. We only
	allow such responses to increase, not decrease, scanning speed by
	disallowing drops (probe->get_tryno() > 0), and we don't allow changing the ping
	probe to something that's likely to get dropped. */
	if (rcvdtime != NULL && newstate != HOST_UP) {
	if (probe->get_tryno() > 0) {
	if (adjust_timing && o.debugging > 1)
	log_write(LOG_PLAIN, "Response for %s means new state is down; not adjusting timing.\n", hss->target->targetipstr());
	adjust_timing = false;
	}
	adjust_ping = false;
	}

	if (adjust_timing)
	ultrascan_adjust_timing(USI, hss, probe, rcvdtime);

	/* If this probe received a positive response, consider making it the new
	timing ping probe. */
	if (rcvdtime != NULL && adjust_ping
	&& pingprobe_is_better(probe->pspec(), PORT_UNKNOWN, &hss->target->pingprobe, hss->target->pingprobe_state)) {
	if (o.debugging > 1) {
	char buf[64];
	probespec2ascii(probe->pspec(), buf, sizeof(buf));
	log_write(LOG_PLAIN, "Changing ping technique for %s to %s\n", hss->target->targetipstr(), buf);
	}
	hss->target->pingprobe = *probe->pspec();
	hss->target->pingprobe_state = PORT_UNKNOWN;
	}

	hss->destroyOutstandingProbe(probeI);
	}

	/* This function is called when a new status is determined for a port.
	the port in the probeI of host hss is now in newstate. This
	function needs to update timing information, other stats, and the
	Nmap port state table as appropriate. If rcvdtime is NULL or we got
	unimportant packet, packet stats are not updated. If you don't have an
	UltraProbe list iterator, you may need to call ultrascan_port_psec_update()
	instead. If adjust_timing_hint is false, packet stats are not
	updated. */
	void ultrascan_port_probe_update(UltraScanInfo USI, HostScanStats hss,
	std::list<UltraProbe *>::iterator probeI,
	int newstate, struct timeval *rcvdtime,
	bool adjust_timing_hint) {
	UltraProbe probe = probeI;
	const probespec *pspec = probe->pspec();

	ultrascan_port_pspec_update(USI, hss, pspec, newstate);

	ultrascan_adjust_timeouts(USI, hss, probe, rcvdtime);

	/* Decide whether to adjust timing. We and together a bunch of conditions.
	First, don't adjust timing if adjust_timing_hint is false. */
	bool adjust_timing = adjust_timing_hint;
	bool adjust_ping = adjust_timing_hint;

	/* If we got a response that meant "filtered", then it was an ICMP error.
	These are often rate-limited (RFC 1812) or generated by a different host.
	We only allow such responses to increase, not decrease, scanning speed by
	not considering drops (probe->get_tryno() > 0), and we don't allow changing the
	ping probe to something that's likely to get dropped. */
	if (rcvdtime != NULL && newstate == PORT_FILTERED && !USI->noresp_open_scan) {
	if (probe->get_tryno() > 0) {
	if (adjust_timing && o.debugging > 1)
	log_write(LOG_PLAIN, "Response for %s means new state is filtered; not adjusting timing.\n", hss->target->targetipstr());
	adjust_timing = false;
	}
	adjust_ping = false;
	}
	/* Do not slow down if
	1) we are in --defeat-rst-ratelimit mode
	2) the new state is closed
	3) this is not a UDP scan (other scans where noresp_open_scan is true
	aren't possible with the --defeat-rst-ratelimit option)
	We don't care if it's closed because of a RST or a timeout
	because they both mean the same thing. */
	if (rcvdtime != NULL
	&& o.defeat_rst_ratelimit && newstate == PORT_CLOSED
	&& !USI->noresp_open_scan) {
	if (probe->get_tryno() > 0)
	adjust_timing = false;
	adjust_ping = false;
	}
	/* Do not slow down if
	1) we are in --defeat-icmp-ratelimit mode
	2) the new state is closed or filtered
	3) this is a UDP scan
	We don't want to adjust timing when we get ICMP response, as the host might
	be ratelimiting them. E.g. the port is actually closed, but the host ratelimiting
	ICMP responses so we had to retransmit the probe several times in order to
	match the (slow) rate limit that the target is using for responses. We
	do not want to waste time on such ports.
	On the other hand if the port is detected to be open it is a good idea to
	adjust timing as we could have done retransmissions due to conjested network */
	if (rcvdtime != NULL
	&& o.defeat_icmp_ratelimit
	&& (newstate == PORT_CLOSED \|\| newstate == PORT_FILTERED)
	&& USI->udp_scan) {
	if (probe->get_tryno() > 0)
	adjust_timing = false;
	adjust_ping = false;
	}

	if (adjust_timing) {
	ultrascan_adjust_timing(USI, hss, probe, rcvdtime);

	if (rcvdtime != NULL && probe->get_tryno() > hss->max_successful_tryno) {
	/* We got a positive response to a higher tryno than we've seen so far. */
	hss->max_successful_tryno = probe->get_tryno();
	if (o.debugging)
	log_write(LOG_STDOUT, "Increased max_successful_tryno for %s to %d (packet drop)\n", hss->target->targetipstr(), hss->max_successful_tryno);
	if (hss->max_successful_tryno > ((o.timing_level >= 4) ? 4 : 3)) {
	unsigned int olddelay = hss->sdn.delayms;
	hss->boostScanDelay();
	if (o.verbose && hss->sdn.delayms != olddelay)
	log_write(LOG_STDOUT, "Increasing send delay for %s from %d to %d due to max_successful_tryno increase to %d\n",
	hss->target->targetipstr(), olddelay, hss->sdn.delayms,
	hss->max_successful_tryno);
	}
	}
	}

	/* If this probe received a positive response, consider making it the new
	timing ping probe. */
	if (rcvdtime != NULL && adjust_ping
	&& pingprobe_is_better(probe->pspec(), newstate, &hss->target->pingprobe, hss->target->pingprobe_state)) {
	if (o.debugging > 1) {
	char buf[64];
	probespec2ascii(probe->pspec(), buf, sizeof(buf));
	log_write(LOG_PLAIN, "Changing ping technique for %s to %s\n", hss->target->targetipstr(), buf);
	}
	hss->target->pingprobe = *probe->pspec();
	hss->target->pingprobe_state = newstate;
	}

	hss->destroyOutstandingProbe(probeI);
	}

	static void sendNextScanProbe(UltraScanInfo USI, HostScanStats hss) {
	probespec pspec;
	tryno_t tryno = {0};

	if (get_next_target_probe(USI, hss, &pspec) == -1) {
	fatal("%s: No more probes! Error in Nmap.", __func__);
	}
	hss->numprobes_sent++;
	USI->gstats->probes_sent++;
	if (pspec.type == PS_ARP)
	sendArpScanProbe(USI, hss, tryno);
	else if (pspec.type == PS_ND)
	sendNDScanProbe(USI, hss, tryno);
	else if (pspec.type == PS_CONNECTTCP)
	sendConnectScanProbe(USI, hss, pspec.pd.tcp.dport, tryno);
	else if (pspec.type == PS_TCP \|\| pspec.type == PS_UDP
	\|\| pspec.type == PS_SCTP \|\| pspec.type == PS_PROTO
	\|\| pspec.type == PS_ICMP \|\| pspec.type == PS_ICMPV6)
	sendIPScanProbe(USI, hss, &pspec, tryno);
	else
	assert(0);
	}

	static void sendNextRetryStackProbe(UltraScanInfo USI, HostScanStats hss) {
	assert(!hss->retry_stack.empty());
	probespec pspec;
	u8 pspec_tries;
	hss->numprobes_sent++;
	USI->gstats->probes_sent++;

	pspec = hss->retry_stack.back();
	hss->retry_stack.pop_back();
	pspec_tries = hss->retry_stack_tries.back();
	hss->retry_stack_tries.pop_back();

	tryno_t tryno = {0};
	tryno.fields.seqnum = pspec_tries + 1;

	if (pspec.type == PS_CONNECTTCP)
	sendConnectScanProbe(USI, hss, pspec.pd.tcp.dport, tryno);
	else {
	assert(pspec.type != PS_ARP && pspec.type != PS_ND);
	sendIPScanProbe(USI, hss, &pspec, tryno);
	}
	}

	static void doAnyNewProbes(UltraScanInfo *USI) {
	HostScanStats hss, unableToSend;

	gettimeofday(&USI->now, NULL);

	/* Loop around the list of incomplete hosts and send a probe to each if
	appropriate. Stop once we've been all the way through the list without
	sending a probe. */
	unableToSend = NULL;
	hss = USI->nextIncompleteHost();
	while (hss != NULL && hss != unableToSend && USI->gstats->sendOK(NULL)) {
	if (hss->freshPortsLeft() && hss->sendOK(NULL)) {
	ultrascan_host_timeout_init(USI, hss);
	sendNextScanProbe(USI, hss);
	unableToSend = NULL;
	} else if (unableToSend == NULL) {
	/* Mark this as the first host we were not able to send to so we can break
	when we see it again. */
	unableToSend = hss;
	}
	hss = USI->nextIncompleteHost();
	}
	}

	static void doAnyRetryStackRetransmits(UltraScanInfo *USI) {
	HostScanStats hss, unableToSend;

	gettimeofday(&USI->now, NULL);

	/* Loop around the list of incomplete hosts and send a probe to each if
	appropriate. Stop once we've been all the way through the list without
	sending a probe. */
	unableToSend = NULL;
	hss = USI->nextIncompleteHost();
	while (hss != NULL && hss != unableToSend && USI->gstats->sendOK(NULL)) {
	if (!hss->retry_stack.empty() && hss->sendOK(NULL)) {
	sendNextRetryStackProbe(USI, hss);
	unableToSend = NULL;
	} else if (unableToSend == NULL) {
	/* Mark this as the first host we were not able to send to so we can break
	when we see it again. */
	unableToSend = hss;
	}
	hss = USI->nextIncompleteHost();
	}
	}

	/* Sends a ping probe to the host. Assumes that caller has already
	checked that sending is OK w/congestion control and that pingprobe is
	available */
	static void sendPingProbe(UltraScanInfo USI, HostScanStats hss) {
	tryno_t tryno = {0};
	tryno.fields.isPing = 1;
	tryno.fields.seqnum = hss->nextPingSeq();

	probespec *pingprobe = &hss->target->pingprobe;
	switch (pingprobe->type) {
	case PS_CONNECTTCP:
	sendConnectScanProbe(USI, hss, pingprobe->pd.tcp.dport, tryno);
	break;
	case PS_TCP:
	case PS_UDP:
	case PS_SCTP:
	case PS_PROTO:
	case PS_ICMP:
	sendIPScanProbe(USI, hss, pingprobe, tryno);
	break;
	case PS_ARP:
	sendArpScanProbe(USI, hss, tryno);
	break;
	case PS_ND:
	sendNDScanProbe(USI, hss, tryno);
	break;
	default:
	assert(0);
	}
	if (o.debugging > 1) {
	char tmpbuf[64];
	log_write(LOG_PLAIN, "Ultrascan PING SENT to %s [%s]\n", hss->target->targetipstr(),
	probespec2ascii(pingprobe, tmpbuf, sizeof(tmpbuf)));
	}
	USI->gstats->probes_sent++;
	}

	static void sendGlobalPingProbe(UltraScanInfo *USI) {
	HostScanStats *hss;

	hss = USI->gstats->pinghost;
	assert(hss != NULL);

	if (o.debugging > 1) {
	char tmpbuf[64];
	log_write(LOG_PLAIN, "Ultrascan GLOBAL PING SENT to %s [%s]\n", hss->target->targetipstr(),
	probespec2ascii(&hss->target->pingprobe, tmpbuf, sizeof(tmpbuf)));
	}
	sendPingProbe(USI, hss);
	}

	static void doAnyPings(UltraScanInfo *USI) {
	std::multiset<HostScanStats *, HssPredicate>::iterator hostI;
	HostScanStats *hss = NULL;

	gettimeofday(&USI->now, NULL);
	/* First single host pings */
	for (hostI = USI->incompleteHosts.begin();
	hostI != USI->incompleteHosts.end(); hostI++) {
	hss = *hostI;
	if (hss->target->pingprobe.type != PS_NONE &&
	hss->rld.rld_waiting == false &&
	hss->numprobes_sent >= hss->lastping_sent_numprobes + 10 &&
	TIMEVAL_SUBTRACT(USI->now, hss->lastrcvd) > USI->perf.pingtime &&
	TIMEVAL_SUBTRACT(USI->now, hss->lastping_sent) > USI->perf.pingtime &&
	USI->gstats->sendOK(NULL) && hss->sendOK(NULL)) {
	sendPingProbe(USI, hss);
	hss->lastping_sent = USI->now;
	hss->lastping_sent_numprobes = hss->numprobes_sent;
	}
	}

	/* Next come global pings. We never send more than one of these at at time. */
	if (USI->gstats->pinghost != NULL &&
	USI->gstats->pinghost->target->pingprobe.type != PS_NONE &&
	USI->gstats->pinghost->num_probes_active == 0 &&
	USI->gstats->probes_sent >= USI->gstats->lastping_sent_numprobes + 20 &&
	TIMEVAL_SUBTRACT(USI->now, USI->gstats->lastrcvd) > USI->perf.pingtime &&
	TIMEVAL_SUBTRACT(USI->now, USI->gstats->lastping_sent) > USI->perf.pingtime &&
	USI->gstats->sendOK(NULL)) {
	sendGlobalPingProbe(USI);
	USI->gstats->lastping_sent = USI->now;
	USI->gstats->lastping_sent_numprobes = USI->gstats->probes_sent;
	}
	}

	/* Retransmit one probe that has presumably been timed out. Only does
	retransmission, does not mark the probe timed out and such. */
	static void retransmitProbe(UltraScanInfo USI, HostScanStats hss,
	UltraProbe *probe) {
	UltraProbe *newProbe = NULL;
	tryno_t tryno = probe->tryno;
	tryno.fields.seqnum++;
	if (probe->type == UltraProbe::UP_IP) {
	if (USI->prot_scan \|\| USI->ptech.rawprotoscan)
	newProbe = sendIPScanProbe(USI, hss, probe->pspec(), tryno);
	else if (probe->protocol() == IPPROTO_TCP) {
	newProbe = sendIPScanProbe(USI, hss, probe->pspec(), tryno);
	} else if (probe->protocol() == IPPROTO_UDP) {
	newProbe = sendIPScanProbe(USI, hss, probe->pspec(), tryno);
	} else if (probe->protocol() == IPPROTO_SCTP) {
	newProbe = sendIPScanProbe(USI, hss, probe->pspec(), tryno);
	} else if (probe->protocol() == IPPROTO_ICMP \|\| probe->protocol() == IPPROTO_ICMPV6) {
	newProbe = sendIPScanProbe(USI, hss, probe->pspec(), tryno);
	} else {
	assert(0);
	}
	} else if (probe->type == UltraProbe::UP_CONNECT) {
	newProbe = sendConnectScanProbe(USI, hss, probe->pspec()->pd.tcp.dport, tryno);
	} else if (probe->type == UltraProbe::UP_ARP) {
	newProbe = sendArpScanProbe(USI, hss, tryno);
	} else if (probe->type == UltraProbe::UP_ND) {
	newProbe = sendNDScanProbe(USI, hss, tryno);
	} else {
	/* TODO: Support any other probe types */
	fatal("%s: unsupported probe type %d", __func__, probe->type);
	}
	if (newProbe)
	newProbe->prevSent = probe->sent;
	probe->retransmitted = true;
	assert(hss->num_probes_waiting_retransmit > 0);
	hss->num_probes_waiting_retransmit--;
	hss->numprobes_sent++;
	USI->gstats->probes_sent++;
	}

	/* Go through the ProbeQueue of each host, identify any
	timed out probes, then try to retransmit them as appropriate */
	static void doAnyOutstandingRetransmits(UltraScanInfo *USI) {
	std::multiset<HostScanStats *, HssPredicate>::iterator hostI;
	std::list<UltraProbe *>::iterator probeI;
	/* A cache of the last processed probe from each host, to avoid re-examining a
	bunch of probes to find the next one that needs to be retransmitted. */
	std::map<HostScanStats , std::list<UltraProbe >::iterator> probe_cache;
	HostScanStats *host = NULL;
	UltraProbe *probe = NULL;
	int retrans = 0; /* Number of retransmissions during a loop */
	unsigned int maxtries;

	struct timeval tv_start = {0};

	gettimeofday(&USI->now, NULL);

	if (o.debugging)
	tv_start = USI->now;

	/* Loop until we get through all the hosts without a retransmit or we're not
	OK to send any more. */
	do {
	retrans = 0;
	for (hostI = USI->incompleteHosts.begin();
	hostI != USI->incompleteHosts.end() && USI->gstats->sendOK(NULL);
	hostI++) {
	host = *hostI;
	/* Skip this host if it has nothing to send. */
	if ((host->num_probes_active == 0
	&& host->num_probes_waiting_retransmit == 0))
	continue;
	if (!host->sendOK(NULL))
	continue;
	assert(!host->probes_outstanding.empty());

	/* Initialize the probe cache if necessary. */
	if (probe_cache.find(host) == probe_cache.end())
	probe_cache[host] = host->probes_outstanding.end();
	/* Restore the probe iterator from the cache. */
	probeI = probe_cache[host];

	maxtries = host->allowedTryno(NULL, NULL);
	do {
	probeI--;
	probe = *probeI;
	if (probe->retransmitted \|\| probe->isPing()) {
	// Don't retransmit these
	continue;
	}
	// Retransmit if timed out and there are still tries remaining
	if (probe->timedout && maxtries > probe->get_tryno()) {
	/* For rate limit detection, we delay the first time a new tryno
	is seen, as long as we are scanning at least 2 ports */
	if (probe->get_tryno() + 1 > (int) host->rld.max_tryno_sent &&
	(USI->gstats->numprobes > 1 \|\| USI->ping_scan_arp \|\| USI->ping_scan_nd)) {
	host->rld.max_tryno_sent = probe->get_tryno() + 1;
	host->rld.rld_waiting = true;
	TIMEVAL_MSEC_ADD(host->rld.rld_waittime, USI->now, RLD_TIME_MS);
	} else {
	host->rld.rld_waiting = false;
	retransmitProbe(USI, host, probe);
	retrans++;
	}
	break; /* I only do one probe per host for now to spread load */
	}
	} while (probeI != host->probes_outstanding.begin());

	/* Wrap the probe iterator around. */
	if (probeI == host->probes_outstanding.begin())
	probeI = host->probes_outstanding.end();
	/* Cache the probe iterator. */
	probe_cache[host] = probeI;
	}
	} while (USI->gstats->sendOK(NULL) && retrans != 0);

	gettimeofday(&USI->now, NULL);
	if (o.debugging) {
	long tv_diff = TIMEVAL_MSEC_SUBTRACT(USI->now, tv_start);
	if (tv_diff > 30)
	log_write(LOG_PLAIN, "%s took %lims\n", __func__, tv_diff);
	}
	}

	/* Print occasional remaining time estimates, as well as
	debugging information */
	static void printAnyStats(UltraScanInfo *USI) {
	std::multiset<HostScanStats *, HssPredicate>::const_iterator hostI;
	const HostScanStats *hss;
	struct ultra_timing_vals hosttm;

	/* Print debugging states for each host being scanned */
	if (o.debugging > 2) {
	log_write(LOG_PLAIN, "TIMING STATS (%.4fs): IP, probes active/freshportsleft/retry_stack/outstanding/retranwait/onbench, cwnd/ssthresh/delay, timeout/srtt/rttvar/\n", o.TimeSinceStart());
	log_write(LOG_PLAIN, " Groupstats (%d/%d incomplete): %d/////* %.2f/%d/* %d/%d/%d\n",
	USI->numIncompleteHosts(), USI->numInitialHosts(),
	USI->gstats->num_probes_active, USI->gstats->timing.cwnd,
	USI->gstats->timing.ssthresh, USI->gstats->to.timeout,
	USI->gstats->to.srtt, USI->gstats->to.rttvar);

	if (o.debugging > 3) {
	for (hostI = USI->incompleteHosts.begin();
	hostI != USI->incompleteHosts.end(); hostI++) {
	hss = *hostI;
	hss->getTiming(&hosttm);
	log_write(LOG_PLAIN, " %s: %d/%d/%d/%d/%d/%d %.2f/%d/%d %li/%d/%d\n", hss->target->targetipstr(),
	hss->num_probes_active, hss->numFreshPortsLeft(),
	(int) hss->retry_stack.size(),
	hss->num_probes_outstanding(),
	hss->num_probes_waiting_retransmit, (int) hss->probe_bench.size(),
	hosttm.cwnd, hosttm.ssthresh, hss->sdn.delayms,
	hss->probeTimeout(), hss->target->to.srtt,
	hss->target->to.rttvar);
	}
	}

	USI->log_current_rates(LOG_PLAIN);
	USI->log_overall_rates(LOG_PLAIN);
	}

	if (USI->SPM->mayBePrinted(&USI->now))
	USI->SPM->printStatsIfNecessary(USI->getCompletionFraction(), &USI->now);
	}

	static void waitForResponses(UltraScanInfo *USI) {
	struct timeval stime;
	bool gotone;
	gettimeofday(&USI->now, NULL);
	USI->gstats->last_wait = USI->now;
	USI->gstats->probes_sent_at_last_wait = USI->gstats->probes_sent;

	do {
	gotone = false;
	USI->sendOK(&stime);
	if (USI->ping_scan_arp) {
	gotone = get_arp_result(USI, &stime);
	} else if (USI->ping_scan_nd) {
	gotone = get_ns_result(USI, &stime);
	} else if (USI->ping_scan) {
	if (USI->pd)
	gotone = get_ping_pcap_result(USI, &stime);
	if (!gotone && USI->ptech.connecttcpscan)
	gotone = do_one_select_round(USI, &stime);
	} else if (USI->pd) {
	gotone = get_pcap_result(USI, &stime);
	} else if (USI->scantype == CONNECT_SCAN) {
	gotone = do_one_select_round(USI, &stime);
	} else assert(0);
	} while (gotone && USI->gstats->num_probes_active > 0);

	gettimeofday(&USI->now, NULL);
	USI->gstats->last_wait = USI->now;
	}

	/* Go through the data structures, making appropriate changes (such as expiring
	probes, noting when hosts are complete, etc. */
	static void processData(UltraScanInfo *USI) {
	std::multiset<HostScanStats *, HssPredicate>::iterator hostI;
	std::list<UltraProbe *>::iterator probeI, nextProbeI;
	HostScanStats *host = NULL;
	UltraProbe *probe = NULL;
	unsigned int maxtries = 0;
	int expire_us = 0;

	bool tryno_capped = false, tryno_mayincrease = false;
	struct timeval tv_start = {0};

	gettimeofday(&USI->now, NULL);

	if (o.debugging)
	tv_start = USI->now;

	/* First go through hosts and remove any completed ones from incompleteHosts */
	USI->removeCompletedHosts();
	if (USI->incompleteHostsEmpty())
	return;

	/* Run through probe lists to:
	1) Mark timedout entries as such
	2) Remove long-expired and retransmitted entries
	3) Detect if we are done (we may just have a bunch of probes
	sitting around waiting to see if another round of
	retransmissions will be required).
	*/
	for (hostI = USI->incompleteHosts.begin();
	hostI != USI->incompleteHosts.end(); hostI++) {
	host = *hostI;
	/* Look for timedout or long expired entries */
	maxtries = host->allowedTryno(&tryno_capped, &tryno_mayincrease);

	/* Should we dump everyone off the bench? */
	if (!host->probe_bench.empty()) {
	if (maxtries == host->bench_tryno && !tryno_mayincrease) {
	/* We'll never need to retransmit these suckers! So they can
	be treated as done */
	host->dismissBench();
	} else if (maxtries > host->bench_tryno) {
	// These fellows may be retransmitted now that maxtries has increased
	host->retransmitBench();
	}
	}

	for (probeI = host->probes_outstanding.begin();
	probeI != host->probes_outstanding.end(); probeI = nextProbeI) {
	nextProbeI = probeI;
	nextProbeI++;
	probe = *probeI;

	// give up completely after this long
	expire_us = host->probeExpireTime(probe);

	if (!probe->timedout && TIMEVAL_SUBTRACT(USI->now, probe->sent) >
	(long) host->probeTimeout()) {
	host->markProbeTimedout(probeI);
	/* Once we've timed out a probe, skip it for this round of processData.
	We don't want it to move to the bench or anything until the other
	functions have had a chance to see that it's timed out. In
	particular, timing out a probe may mean that the tryno can no longer
	increase, which would make the logic below incorrect. */
	continue;
	}

	if (!probe->isPing() && probe->timedout && !probe->retransmitted) {
	if (!tryno_mayincrease && probe->get_tryno() >= maxtries) {
	if (tryno_capped && !host->retry_capped_warned) {
	log_write(LOG_PLAIN, "Warning: %s giving up on port because"
	" retransmission cap hit (%d).\n", host->target->targetipstr(),
	probe->get_tryno());
	host->retry_capped_warned = true;
	}
	if (USI->ping_scan) {
	ultrascan_host_probe_update(USI, host, probeI, HOST_DOWN, NULL);
	if (host->target->reason.reason_id == ER_UNKNOWN)
	host->target->reason.reason_id = ER_NORESPONSE;
	} else {
	/* No ultrascan_port_probe_update because that allocates a Port
	object; the default port state as set by setDefaultPortState
	handles these no-response ports. */
	host->destroyOutstandingProbe(probeI);
	}
	continue;
	} else if (probe->get_tryno() >= maxtries &&
	TIMEVAL_SUBTRACT(USI->now, probe->sent) > expire_us) {
	assert(probe->get_tryno() == maxtries);
	/* Move it to the bench until it is needed (maxtries
	increases or is capped */
	host->moveProbeToBench(probeI);
	continue;
	}
	}

	if ((probe->isPing() \|\| (probe->timedout && probe->retransmitted)) &&
	TIMEVAL_SUBTRACT(USI->now, probe->sent) > expire_us) {
	host->destroyOutstandingProbe(probeI);
	continue;
	}
	}
	}

	/* In case any hosts were completed during this run */
	USI->removeCompletedHosts();

	/* Check for expired global pings. */
	HostScanStats *pinghost = USI->gstats->pinghost;
	if (pinghost != NULL) {
	for (probeI = pinghost->probes_outstanding.begin();
	probeI != pinghost->probes_outstanding.end();
	probeI = nextProbeI) {
	nextProbeI = probeI;
	nextProbeI++;
	/* If a global ping probe times out, we want to get rid of it so a new
	host can take its place. */
	if ((*probeI)->isPing()
	&& TIMEVAL_SUBTRACT(USI->now, (*probeI)->sent) > (long) pinghost->probeTimeout()) {
	if (o.debugging)
	log_write(LOG_STDOUT, "Destroying timed-out global ping from %s.\n", pinghost->target->targetipstr());
	/* ultrascan_ping_update destroys the probe. */
	ultrascan_ping_update(USI, pinghost, probeI, NULL);
	}
	}
	}

	gettimeofday(&USI->now, NULL);
	if (o.debugging) {
	long tv_diff = TIMEVAL_MSEC_SUBTRACT(USI->now, tv_start);
	if (tv_diff > 30)
	log_write(LOG_PLAIN, "%s took %lims\n", __func__, tv_diff);
	}
	}

	/* 3rd generation Nmap scanning function. Handles most Nmap port scan types.

	The parameter to gives group timing information, and if it is not NULL,
	changed timing information will be stored in it when the function returns. It
	exists so timing can be shared across invocations of this function. If to is
	NULL (its default value), a default timeout_info will be used. */
	void ultra_scan(std::vector<Target > &Targets, const struct scan_lists ports,
	stype scantype, struct timeout_info *to) {
	o.current_scantype = scantype;

	/* Load up _all_ payloads into a mapped table. Only needed for raw scans. */

	init_payloads();

	if (Targets.size() == 0) {
	return;
	}

	#ifdef WIN32
	if (g_has_npcap_loopback == 0 && scantype != CONNECT_SCAN && Targets[0]->ifType() == devt_loopback) {
	log_write(LOG_STDOUT, "Skipping %s against %s because Windows does not support scanning your own machine (localhost) this way.\n", scantype2str(scantype), Targets[0]->NameIP());
	return;
	}
	#endif

	// Set the variable for status printing
	o.numhosts_scanning = Targets.size();

	UltraScanInfo USI(Targets, ports, scantype);

	if (USI.gstats->numprobes <= 0) {
	if (o.debugging) {
	log_write(LOG_STDOUT, "Skipping %s: no probes to send\n", scantype2str(scantype));
	}
	return;
	}

	/* Use the requested timeouts. */
	if (to != NULL)
	USI.gstats->to = *to;

	if (o.verbose) {
	char targetstr[128];
	bool plural = (Targets.size() != 1);
	if (!plural) {
	(*(Targets.begin()))->NameIP(targetstr, sizeof(targetstr));
	} else Snprintf(targetstr, sizeof(targetstr), "%d hosts", (int) Targets.size());
	log_write(LOG_STDOUT, "Scanning %s [%d port%s%s]\n", targetstr, USI.gstats->numprobes, (USI.gstats->numprobes != 1) ? "s" : "", plural ? "/host" : "");
	}

	if (USI.isRawScan())
	begin_sniffer(&USI, Targets);
	/* Otherwise, no sniffer needed! */

	while (!USI.incompleteHostsEmpty()) {
	doAnyPings(&USI);
	doAnyOutstandingRetransmits(&USI); // Retransmits from probes_outstanding
	/* Retransmits from retry_stack -- goes after OutstandingRetransmits for
	memory consumption reasons */
	doAnyRetryStackRetransmits(&USI);
	doAnyNewProbes(&USI);
	gettimeofday(&USI.now, NULL);
	// printf("TRACE: Finished doAnyNewProbes() at %.4fs\n", o.TimeSinceStartMS(&USI.now) / 1000.0);
	printAnyStats(&USI);
	waitForResponses(&USI);
	gettimeofday(&USI.now, NULL);
	// printf("TRACE: Finished waitForResponses() at %.4fs\n", o.TimeSinceStartMS(&USI.now) / 1000.0);
	processData(&USI);

	if (keyWasPressed()) {
	// This prints something like
	// SYN Stealth Scan Timing: About 1.14% done; ETC: 15:01 (0:43:23 remaining);
	USI.SPM->printStats(USI.getCompletionFraction(), NULL);
	if (o.debugging) {
	/* Don't update when getting the current rates, otherwise we can get
	anomalies (rates are too low) from having just done a potentially
	long waitForResponses without sending any packets. */
	USI.log_current_rates(LOG_STDOUT, false);
	}

	log_flush(LOG_STDOUT);
	}
	}

	USI.send_rate_meter.stop(&USI.now);

	/* Save the computed timeouts. */
	if (to != NULL)
	*to = USI.gstats->to;

	if (o.verbose) {
	char additional_info[128];
	if (USI.gstats->num_hosts_timedout == 0)
	if (USI.ping_scan) {
	Snprintf(additional_info, sizeof(additional_info), "%lu total hosts",
	(unsigned long) Targets.size());
	} else {
	Snprintf(additional_info, sizeof(additional_info), "%lu total ports",
	(unsigned long) USI.gstats->numprobes * Targets.size());
	}
	else Snprintf(additional_info, sizeof(additional_info), "%d %s timed out",
	USI.gstats->num_hosts_timedout,
	(USI.gstats->num_hosts_timedout == 1) ? "host" : "hosts");
	USI.SPM->endTask(NULL, additional_info);
	}
	if (o.debugging)
	USI.log_overall_rates(LOG_STDOUT);

	if (o.debugging > 2 && USI.pd != NULL)
	pcap_print_stats(LOG_PLAIN, USI.pd);
	}

Sep	OCT	Dec
	22
2020	2021	2023

nmap / nmap Public

nmap/scan_engine.cc