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FPEngine.cc
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/***************************************************************************
* FPEngine.cc -- Routines used for IPv6 OS detection via TCP/IP *
* fingerprinting. * For more information on how this works in Nmap, see *
* https://nmap.org/osdetect/ *
* *
***********************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 dev@nmap.org 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. *
* *
***************************************************************************/
/* $Id$ */
#include "FPEngine.h"
#include "Target.h"
#include "FingerPrintResults.h"
#include "NmapOps.h"
#include "nmap_error.h"
#include "osscan.h"
#include "linear.h"
#include "FPModel.h"
#include "tcpip.h"
#include "string_pool.h"
extern NmapOps o;
#ifdef WIN32
/* Need DnetName2PcapName */
#include "libnetutil/netutil.h"
/* from libdnet's intf-win32.c */
extern "C" int g_has_npcap_loopback;
#endif
#include <math.h>
/******************************************************************************
* Globals. *
******************************************************************************/
/* This is the global network controller. FPHost classes use it to request
* network resources and schedule packet transmissions. */
FPNetworkControl global_netctl;
/******************************************************************************
* Implementation of class FPNetworkControl. *
******************************************************************************/
FPNetworkControl::FPNetworkControl() {
memset(&this->nsp, 0, sizeof(nsock_pool));
memset(&this->pcap_nsi, 0, sizeof(pcap_nsi));
memset(&this->pcap_ev_id, 0, sizeof(nsock_event_id));
this->nsock_init = false;
this->rawsd = -1;
this->probes_sent = 0;
this->responses_recv = 0;
this->probes_timedout = 0;
this->cc_cwnd = 0;
this->cc_ssthresh = 0;
}
FPNetworkControl::~FPNetworkControl() {
if (this->nsock_init) {
nsock_event_cancel(this->nsp, this->pcap_ev_id, 0);
nsock_pool_delete(this->nsp);
this->nsock_init = false;
}
}
/* (Re)-Initialize object's state (default parameter setup and nsock
* initialization). */
void FPNetworkControl::init(const char *ifname, devtype iftype) {
/* Init congestion control parameters */
this->cc_init();
/* If there was a previous nsock pool, delete it */
if (this->pcap_nsi) {
nsock_iod_delete(this->pcap_nsi, NSOCK_PENDING_SILENT);
}
if (this->nsock_init) {
nsock_event_cancel(this->nsp, this->pcap_ev_id, 0);
nsock_pool_delete(this->nsp);
}
/* Create a new nsock pool */
if ((this->nsp = nsock_pool_new(NULL)) == NULL)
fatal("Unable to obtain an Nsock pool");
nmap_set_nsock_logger();
nmap_adjust_loglevel(o.packetTrace());
nsock_pool_set_device(nsp, o.device);
if (o.proxy_chain)
nsock_pool_set_proxychain(this->nsp, o.proxy_chain);
/* Allow broadcast addresses */
nsock_pool_set_broadcast(this->nsp, 1);
/* Allocate an NSI for packet capture */
this->pcap_nsi = nsock_iod_new(this->nsp, NULL);
this->first_pcap_scheduled = false;
/* Flag it as already initialized so we free this nsp next time */
this->nsock_init = true;
/* Obtain raw socket or check that we can obtain an eth descriptor. */
if ((o.sendpref & PACKET_SEND_ETH) && (iftype == devt_ethernet
#ifdef WIN32
|| (g_has_npcap_loopback && iftype == devt_loopback)
#endif
) && ifname != NULL) {
/* We don't need to store the eth handler because FPProbes come with a
* suitable one (FPProbes::getEthernet()), we just attempt to obtain one
* to see if it fails. */
if (eth_open_cached(ifname) == NULL)
fatal("dnet: failed to open device %s", ifname);
this->rawsd = -1;
} else {
#ifdef WIN32
win32_fatal_raw_sockets(ifname);
#endif
if (this->rawsd >= 0)
close(this->rawsd);
rawsd = nmap_raw_socket();
if (rawsd < 0)
pfatal("Couldn't obtain raw socket in %s", __func__);
}
/* De-register existing callers */
while (this->callers.size() > 0) {
this->callers.pop_back();
}
return;
}
/* This function initializes the controller's congestion control parameters.
* The network controller uses TCP's Slow Start and Congestion Avoidance
* algorithms from RFC 5681 (slightly modified for convenience).
*
* As the OS detection process does not open full TCP connections, we can't just
* use ACKs (or the lack of ACKs) to increase or decrease the congestion window
* so we use probe responses. Every time we get a response to an OS detection
* probe, we treat it as if it was a TCP ACK in TCP's congestion control.
*
* Note that the initial Congestion Window is set to the number of timed
* probes that we send to each target. This is necessary since we need to
* know for sure that we can send that many packets in order to transmit them.
* Otherwise, we could fail to deliver the probes 100ms apart. */
int FPNetworkControl::cc_init() {
this->probes_sent = 0;
this->responses_recv = 0;
this->probes_timedout = 0;
this->cc_cwnd = OSSCAN_INITIAL_CWND;
this->cc_ssthresh = OSSCAN_INITIAL_SSTHRESH;
return OP_SUCCESS;
}
/* This method is used to indicate that we have scheduled the transmission of
* one or more packets. This is used in congestion control to determine the
* number of outstanding probes (number of probes sent but not answered yet)
* and therefore, the effective transmission window. @param pkts indicates the
* number of packets that were scheduled. Returns OP_SUCCESS on success and
* OP_FAILURE in case of error. */
int FPNetworkControl::cc_update_sent(int pkts = 1) {
if (pkts <= 0)
return OP_FAILURE;
this->probes_sent+=pkts;
return OP_SUCCESS;
}
/* This method is used to indicate that a drop has occurred. In TCP, drops are
* detected by the absence of an ACK. However, we can't use that, since it is
* very likely that our targets do not respond to some of our OS detection
* probes intentionally. For this reason, we consider that a drop has occurred
* when we receive a response for a probe that has already suffered one
* retransmission (first transmission got dropped in transit, some later
* transmission made it to the host and it responded). So when we detect a drop
* we do the same as TCP, adjust the congestion window and the slow start
* threshold. */
int FPNetworkControl::cc_report_drop() {
/* FROM RFC 5681
When a TCP sender detects segment loss using the retransmission timer
and the given segment has not yet been resent by way of the
retransmission timer, the value of ssthresh MUST be set to no more
than the value given in equation (4):
ssthresh = max (FlightSize / 2, 2*SMSS) (4)
where, as discussed above, FlightSize is the amount of outstanding
data in the network.
On the other hand, when a TCP sender detects segment loss using the
retransmission timer and the given segment has already been
retransmitted by way of the retransmission timer at least once, the
value of ssthresh is held constant.
*/
int probes_outstanding = this->probes_sent - this->responses_recv - this->probes_timedout;
this->cc_ssthresh = (float)MAX(probes_outstanding, OSSCAN_INITIAL_CWND);
this->cc_cwnd = OSSCAN_INITIAL_CWND;
return OP_SUCCESS;
}
/* This method is used to indicate that a response to a previous probe was
* received. For us this is like getting and ACK in TCP congestion control, so
* we update the congestion window (increase by one packet if we are in slow
* start or increase it by a small percentage of a packet if we are in
* congestion avoidance). */
int FPNetworkControl::cc_update_received() {
this->responses_recv++;
/* If we are in Slow Start, increment congestion window by one packet.
* (Note that we treat probe responses the same way TCP CC treats ACKs). */
if (this->cc_cwnd < this->cc_ssthresh) {
this->cc_cwnd += 1;
/* Otherwise we are in Congestion Avoidance and CWND is incremented slowly,
* approximately one packet per RTT */
} else {
this->cc_cwnd = this->cc_cwnd + 1/this->cc_cwnd;
}
if (o.debugging > 3) {
log_write(LOG_PLAIN, "[FPNetworkControl] Congestion Control Parameters: cwnd=%f ssthresh=%f sent=%d recv=%d tout=%d outstanding=%d\n",
this->cc_cwnd, this->cc_ssthresh, this->probes_sent, this->responses_recv, this->probes_timedout,
this->probes_sent - this->responses_recv - this->probes_timedout);
}
return OP_SUCCESS;
}
/* This method is public and can be called by FPHosts to inform the controller
* that a probe has experienced a final timeout. In other words, that no
* response was received for the probe after doing the necessary retransmissions
* and waiting for the RTO. This is used to decrease the number of outstanding
* probes. Otherwise, if no host responded to the probes, the effective
* transmission window could reach zero and prevent new probes from being sent,
* clogging the engine. */
int FPNetworkControl::cc_report_final_timeout() {
this->probes_timedout++;
return OP_SUCCESS;
}
/* This method is used by FPHosts to request permission to transmit a number of
* probes. Permission is granted if the current congestion window allows the
* transmission of new probes. It returns true if permission is granted and
* false if it is denied. */
bool FPNetworkControl::request_slots(size_t num_packets) {
int probes_outstanding = this->probes_sent - this->responses_recv - this->probes_timedout;
if (o.debugging > 3)
log_write(LOG_PLAIN, "[FPNetworkControl] Slot request for %u packets. ProbesOutstanding=%d cwnd=%f ssthresh=%f\n",
(unsigned int)num_packets, probes_outstanding, this->cc_cwnd, this->cc_ssthresh);
/* If we still have room for more outstanding probes, let the caller
* schedule transmissions. */
if ((probes_outstanding + num_packets) <= this->cc_cwnd) {
this->cc_update_sent(num_packets);
return true;
}
return false;
}
/* This method lets FPHosts register themselves in the network controller so
* the controller can call them back every time a packet they are interested
* in is captured.*/
int FPNetworkControl::register_caller(FPHost *newcaller) {
this->callers.push_back(newcaller);
return OP_SUCCESS;
}
/* This method lets FPHosts unregister themselves in the network controller so
* the controller does not call them back again. This is called by hosts that
* have already finished their OS detection. */
int FPNetworkControl::unregister_caller(FPHost *oldcaller) {
for (size_t i = 0; i < this->callers.size(); i++) {
if (this->callers[i] == oldcaller) {
this->callers.erase(this->callers.begin() + i);
return OP_SUCCESS;
}
}
return OP_FAILURE;
}
/* This method gets the controller ready for packet capture. Basically it
* obtains a pcap descriptor from nsock and sets an appropriate BPF filter. */
int FPNetworkControl::setup_sniffer(const char *iface, const char *bpf_filter) {
char pcapdev[128];
int rc;
#ifdef WIN32
/* Nmap normally uses device names obtained through dnet for interfaces, but
Pcap has its own naming system. So the conversion is done here */
if (!DnetName2PcapName(iface, pcapdev, sizeof(pcapdev))) {
/* Oh crap -- couldn't find the corresponding dev apparently. Let's just go
with what we have then ... */
Strncpy(pcapdev, iface, sizeof(pcapdev));
}
#else
Strncpy(pcapdev, iface, sizeof(pcapdev));
#endif
/* Obtain a pcap descriptor */
rc = nsock_pcap_open(this->nsp, this->pcap_nsi, pcapdev, 8192, 0, bpf_filter);
if (rc)
fatal("Error opening capture device %s\n", pcapdev);
/* Store the pcap NSI inside the pool so we can retrieve it inside a callback */
nsock_pool_set_udata(this->nsp, (void *)&(this->pcap_nsi));
return OP_SUCCESS;
}
/* This method makes the controller process pending events (like packet
* transmissions or packet captures). */
void FPNetworkControl::handle_events() {
nmap_adjust_loglevel(o.packetTrace());
nsock_loop(nsp, 50);
}
/* This method lets FPHosts to schedule the transmission of an OS detection
* probe. It takes an FPProbe pointer and the amount of milliseconds the
* controller should wait before injecting the probe into the wire. */
int FPNetworkControl::scheduleProbe(FPProbe *pkt, int in_msecs_time) {
nsock_timer_create(this->nsp, probe_transmission_handler_wrapper, in_msecs_time, (void*)pkt);
return OP_SUCCESS;
}
/* This is the handler for packet transmission. It is called by nsock whenever a timer expires,
* which means that a new packet needs to be transmitted. Note that this method is not
* called directly by Nsock but by the wrapper function probe_transmission_handler_wrapper().
* The reason for that is because C++ does not allow to use class methods as callback
* functions, so this is a small hack to make that happen. */
void FPNetworkControl::probe_transmission_handler(nsock_pool nsp, nsock_event nse, void *arg) {
assert(nsock_pool_get_udata(nsp) != NULL);
nsock_iod nsi_pcap = *((nsock_iod *)nsock_pool_get_udata(nsp));
enum nse_status status = nse_status(nse);
enum nse_type type = nse_type(nse);
FPProbe *myprobe = (FPProbe *)arg;
u8 *buf;
size_t len;
int result;
if (status == NSE_STATUS_SUCCESS) {
switch(type) {
/* Timer events mean that we need to send a packet. */
case NSE_TYPE_TIMER:
/* The first time a packet is sent, we schedule a pcap event. After that
* we don't have to worry since the response reception handler schedules
* a new capture event for each captured packet. */
if (!this->first_pcap_scheduled) {
this->pcap_ev_id = nsock_pcap_read_packet(nsp, nsi_pcap, response_reception_handler_wrapper, -1, NULL);
this->first_pcap_scheduled = true;
}
/* Send the packet*/
for (int decoy = 0; decoy < o.numdecoys; decoy++) {
result = myprobe->changeSourceAddress(&((struct sockaddr_in6 *)&o.decoys[decoy])->sin6_addr);
assert(result == OP_SUCCESS);
assert(myprobe->host != NULL);
buf = myprobe->getPacketBuffer(&len);
if (send_ip_packet(this->rawsd, myprobe->getEthernet(), myprobe->host->getTargetAddress(), buf, len) == -1) {
if (decoy == o.decoyturn) {
myprobe->setFailed();
this->cc_report_final_timeout();
myprobe->host->fail_one_probe();
gh_perror("Unable to send packet in %s", __func__);
}
}
if (decoy == o.decoyturn) {
myprobe->setTimeSent();
}
free(buf);
}
/* Reset the address to the original one if decoys were present and original Address wasn't last one */
if ( o.numdecoys != o.decoyturn+1 ) {
result = myprobe->changeSourceAddress(&((struct sockaddr_in6 *)&o.decoys[o.decoyturn])->sin6_addr);
assert(result == OP_SUCCESS);
}
break;
default:
fatal("Unexpected Nsock event in probe_transmission_handler()");
break;
} /* switch(type) */
} else if (status == NSE_STATUS_EOF) {
if (o.debugging)
log_write(LOG_PLAIN, "probe_transmission_handler(): EOF\n");
} else if (status == NSE_STATUS_ERROR || status == NSE_STATUS_PROXYERROR) {
if (o.debugging)
log_write(LOG_PLAIN, "probe_transmission_handler(): %s failed: %s\n", nse_type2str(type), strerror(socket_errno()));
} else if (status == NSE_STATUS_TIMEOUT) {
if (o.debugging)
log_write(LOG_PLAIN, "probe_transmission_handler(): %s timeout: %s\n", nse_type2str(type), strerror(socket_errno()));
} else if (status == NSE_STATUS_CANCELLED) {
if (o.debugging)
log_write(LOG_PLAIN, "probe_transmission_handler(): %s canceled: %s\n", nse_type2str(type), strerror(socket_errno()));
} else if (status == NSE_STATUS_KILL) {
if (o.debugging)
log_write(LOG_PLAIN, "probe_transmission_handler(): %s killed: %s\n", nse_type2str(type), strerror(socket_errno()));
} else {
if (o.debugging)
log_write(LOG_PLAIN, "probe_transmission_handler(): Unknown status code %d\n", status);
}
return;
}
/* This is the handler for packet capture. It is called by nsock whenever libpcap
* captures a packet from the network interface. This method basically captures
* the packet, extracts its source IP address and tries to find an FPHost that
* is targeting such address. If it does, it passes the packet to that FPHost
* via callback() so the FPHost can determine if the packet is actually the
* response to a FPProbe that it sent before. Note that this method is not
* called directly by Nsock but by the wrapper function
* response_reception_handler_wrapper(). See doc in probe_transmission_handler()
* for details. */
void FPNetworkControl::response_reception_handler(nsock_pool nsp, nsock_event nse, void *arg) {
nsock_iod nsi = nse_iod(nse);
enum nse_status status = nse_status(nse);
enum nse_type type = nse_type(nse);
const u8 *rcvd_pkt = NULL; /* Points to the captured packet */
size_t rcvd_pkt_len = 0; /* Length of the captured packet */
struct timeval pcaptime; /* Time the packet was captured */
struct sockaddr_storage sent_ss;
struct sockaddr_storage rcvd_ss;
struct sockaddr_in *rcvd_ss4 = (struct sockaddr_in *)&rcvd_ss;
struct sockaddr_in6 *rcvd_ss6 = (struct sockaddr_in6 *)&rcvd_ss;
memset(&rcvd_ss, 0, sizeof(struct sockaddr_storage));
IPv4Header ip4;
IPv6Header ip6;
int res = -1;
struct timeval tv;
gettimeofday(&tv, NULL);
if (status == NSE_STATUS_SUCCESS) {
switch(type) {
case NSE_TYPE_PCAP_READ:
/* Schedule a new pcap read operation */
this->pcap_ev_id = nsock_pcap_read_packet(nsp, nsi, response_reception_handler_wrapper, -1, NULL);
/* Get captured packet */
nse_readpcap(nse, NULL, NULL, &rcvd_pkt, &rcvd_pkt_len, NULL, &pcaptime);
/* Extract the packet's source address */
ip4.storeRecvData(rcvd_pkt, rcvd_pkt_len);
if (ip4.validate() != OP_FAILURE && ip4.getVersion() == 4) {
ip4.getSourceAddress(&(rcvd_ss4->sin_addr));
rcvd_ss4->sin_family = AF_INET;
} else {
ip6.storeRecvData(rcvd_pkt, rcvd_pkt_len);
if (ip6.validate() != OP_FAILURE && ip6.getVersion() == 6) {
ip6.getSourceAddress(&(rcvd_ss6->sin6_addr));
rcvd_ss6->sin6_family = AF_INET6;
} else {
/* If we get here it means that the received packet is not
* IPv4 or IPv6 so we just discard it returning. */
return;
}
}
/* Check if we have a caller that expects packets from this sender */
for (size_t i = 0; i < this->callers.size(); i++) {
/* Obtain the target address */
sent_ss = *this->callers[i]->getTargetAddress();
/* Check that the received packet is of the same address family */
if (sent_ss.ss_family != rcvd_ss.ss_family)
continue;
/* Check that the captured packet's source address matches the
* target address. If it matches, pass the received packet
* to the appropriate FPHost object through callback(). */
if (sockaddr_storage_equal(&rcvd_ss, &sent_ss)) {
if ((res = this->callers[i]->callback(rcvd_pkt, rcvd_pkt_len, &tv)) >= 0) {
/* If callback() returns >=0 it means that the packet we've just
* passed was successfully matched with a previous probe. Now
* update the count of received packets (so we can determine how
* many outstanding packets are out there). Note that we only do
* that if callback() returned >0 because 0 is a special case: a
* reply to a retransmitted timed probe that was already replied
* to in the past. We don't want to count replies to the same probe
* more than once, so that's why we only update when res > 0. */
if (res > 0)
this->cc_update_received();
/* When the callback returns more than 1 it means that the packet
* was sent more than once before being answered. This means that
* we experienced congestion (first transmission got dropped), so
* we update our CC parameters to deal with the congestion. */
if (res > 1) {
this->cc_report_drop();
}
}
return;
}
}
break;
default:
fatal("Unexpected Nsock event in response_reception_handler()");
break;
} /* switch(type) */
} else if (status == NSE_STATUS_EOF) {
if (o.debugging)
log_write(LOG_PLAIN, "response_reception_handler(): EOF\n");
} else if (status == NSE_STATUS_ERROR || status == NSE_STATUS_PROXYERROR) {
if (o.debugging)
log_write(LOG_PLAIN, "response_reception_handler(): %s failed: %s\n", nse_type2str(type), strerror(socket_errno()));
} else if (status == NSE_STATUS_TIMEOUT) {
if (o.debugging)
log_write(LOG_PLAIN, "response_reception_handler(): %s timeout: %s\n", nse_type2str(type), strerror(socket_errno()));
} else if (status == NSE_STATUS_CANCELLED) {
if (o.debugging)
log_write(LOG_PLAIN, "response_reception_handler(): %s canceled: %s\n", nse_type2str(type), strerror(socket_errno()));
} else if (status == NSE_STATUS_KILL) {
if (o.debugging)
log_write(LOG_PLAIN, "response_reception_handler(): %s killed: %s\n", nse_type2str(type), strerror(socket_errno()));
} else {
if (o.debugging)
log_write(LOG_PLAIN, "response_reception_handler(): Unknown status code %d\n", status);
}
return;
}
/******************************************************************************
* Implementation of class FPEngine. *
******************************************************************************/
FPEngine::FPEngine() {
this->osgroup_size = OSSCAN_GROUP_SIZE;
}
FPEngine::~FPEngine() {
}
/* Returns a suitable BPF filter for the OS detection. If less than 20 targets
* are passed, the filter contains an explicit list of target addresses. It
* looks similar to this:
*
* dst host fe80::250:56ff:fec0:1 and (src host fe80::20c:29ff:feb0:2316 or src host fe80::20c:29ff:fe9f:5bc2)
*
* When more than 20 targets are passed, a generic filter based on the source
* address is used. The returned filter looks something like:
*
* dst host fe80::250:56ff:fec0:1
*/
const char *FPEngine::bpf_filter(std::vector<Target *> &Targets) {
static char pcap_filter[2048];
/* 20 IPv6 addresses is max (46 byte addy + 14 (" or src host ")) * 20 == 1200 */
char dst_hosts[1220];
int filterlen = 0;
int len = 0;
unsigned int targetno;
memset(pcap_filter, 0, sizeof(pcap_filter));
/* If we have 20 or less targets, build a list of addresses so we can set
* an explicit BPF filter */
if (Targets.size() <= 20) {
for (targetno = 0; targetno < Targets.size(); targetno++) {
len = Snprintf(dst_hosts + filterlen,
sizeof(dst_hosts) - filterlen,
"%ssrc host %s", (targetno == 0)? "" : " or ",
Targets[targetno]->targetipstr());
if (len < 0 || len + filterlen >= (int) sizeof(dst_hosts))
fatal("ran out of space in dst_hosts");
filterlen += len;
}
len = Snprintf(pcap_filter, sizeof(pcap_filter), "dst host %s and (%s)",
Targets[0]->sourceipstr(), dst_hosts);
} else {
len = Snprintf(pcap_filter, sizeof(pcap_filter), "dst host %s", Targets[0]->sourceipstr());
}
if (len < 0 || len >= (int) sizeof(pcap_filter))
fatal("ran out of space in pcap filter");
return pcap_filter;
}
/******************************************************************************
* Implementation of class FPEngine6. *
******************************************************************************/
FPEngine6::FPEngine6() {
}
FPEngine6::~FPEngine6() {
}
/* Not all operating systems allow setting the flow label in outgoing packets;
notably all Unixes other than Linux when using raw sockets. This function
finds out whether the flow labels we set are likely really being sent.
Otherwise, the operating system is probably filling in 0. Compare to the
logic in send_ipv6_packet_eth_or_sd. */
static bool can_set_flow_label(const struct eth_nfo *eth) {
if (eth != NULL)
return true;
#if HAVE_IPV6_IPPROTO_RAW
return true;
#else
return false;
#endif
}
void FPHost6::fill_FPR(FingerPrintResultsIPv6 *FPR) {
unsigned int i;
FPR->begin_time = this->begin_time;
for (i = 0; i < sizeof(this->fp_responses) / sizeof(this->fp_responses[0]); i++) {
const FPResponse *resp;
resp = this->fp_responses[i];
if (resp != NULL) {
FPR->fp_responses[i] = new FPResponse(resp->probe_id, resp->buf, resp->len,
resp->senttime, resp->rcvdtime);
}
}
/* Were we actually able to set the flow label? */
FPR->flow_label = 0;
for (i = 0; i < sizeof(this->fp_probes) / sizeof(this->fp_probes[0]); i++) {
const FPProbe& probe = fp_probes[0];
if (probe.is_set()) {
if (can_set_flow_label(probe.getEthernet()))
FPR->flow_label = OSDETECT_FLOW_LABEL;
break;
}
}
/* Did we fail to send some probe? */
FPR->incomplete = this->incomplete_fp;
}
static IPv6Header *find_ipv6(const PacketElement *pe) {
while (pe != NULL && pe->protocol_id() != HEADER_TYPE_IPv6)
pe = pe->getNextElement();
return (IPv6Header *) pe;
}
static const TCPHeader *find_tcp(const PacketElement *pe) {
while (pe != NULL && pe->protocol_id() != HEADER_TYPE_TCP)
pe = pe->getNextElement();
return (TCPHeader *) pe;
}
static const ICMPv6Header *find_icmpv6(const PacketElement *pe) {
while (pe != NULL && pe->protocol_id() != HEADER_TYPE_ICMPv6)
pe = pe->getNextElement();
return (ICMPv6Header *) pe;
}
static double vectorize_plen(const PacketElement *pe) {
const IPv6Header *ipv6;
ipv6 = find_ipv6(pe);
if (ipv6 == NULL)
return -1;
else
return ipv6->getPayloadLength();
}
static double vectorize_tc(const PacketElement *pe) {
const IPv6Header *ipv6;
ipv6 = find_ipv6(pe);
if (ipv6 == NULL)
return -1;
else
return ipv6->getTrafficClass();
}
/* For reference, the dev@nmap.org email thread which contains the explanations for the
* design decisions of this vectorization method:
* http://seclists.org/nmap-dev/2015/q1/218
*/
static int vectorize_hlim(const PacketElement *pe, int target_distance, enum dist_calc_method method) {
const IPv6Header *ipv6;
int hlim;
int er_lim;
ipv6 = find_ipv6(pe);
if (ipv6 == NULL)
return -1;
hlim = ipv6->getHopLimit();
if (method != DIST_METHOD_NONE) {
if (method == DIST_METHOD_TRACEROUTE || method == DIST_METHOD_ICMP) {
if (target_distance > 0)
hlim += target_distance - 1;
}
er_lim = 5;
} else
er_lim = 20;
if (32 - er_lim <= hlim && hlim <= 32+ 5 )
hlim = 32;
else if (64 - er_lim <= hlim && hlim <= 64+ 5 )
hlim = 64;
else if (128 - er_lim <= hlim && hlim <= 128+ 5 )
hlim = 128;
else if (255 - er_lim <= hlim && hlim <= 255+ 5 )
hlim = 255;
else
hlim = -1;
return hlim;
}
static double vectorize_isr(std::map<std::string, FPPacket>& resps) {
const char * const SEQ_PROBE_NAMES[] = {"S1", "S2", "S3", "S4", "S5", "S6"};
u32 seqs[NELEMS(SEQ_PROBE_NAMES)];
struct timeval times[NELEMS(SEQ_PROBE_NAMES)];
unsigned int i, j;
double sum, t;
j = 0;
for (i = 0; i < NELEMS(SEQ_PROBE_NAMES); i++) {
const char *probe_name;
const FPPacket *fp;
const TCPHeader *tcp;
std::map<std::string, FPPacket>::const_iterator it;
probe_name = SEQ_PROBE_NAMES[i];
it = resps.find(probe_name);
if (it == resps.end())
continue;
fp = &it->second;
tcp = find_tcp(fp->getPacket());
if (tcp == NULL)
continue;
seqs[j] = tcp->getSeq();
times[j] = fp->getTime();
j++;
}
if (j < 2)
return -1;
sum = 0.0;
for (i = 0; i < j - 1; i++)
sum += seqs[i + 1] - seqs[i];
t = TIMEVAL_FSEC_SUBTRACT(times[j - 1], times[0]);
return sum / t;
}
static int vectorize_icmpv6_type(const PacketElement *pe) {
const ICMPv6Header *icmpv6;
icmpv6 = find_icmpv6(pe);
if (icmpv6 == NULL)
return -1;
return icmpv6->getType();
}
static int vectorize_icmpv6_code(const PacketElement *pe) {
const ICMPv6Header *icmpv6;
icmpv6 = find_icmpv6(pe);
if (icmpv6 == NULL)
return -1;
return icmpv6->getCode();
}
static struct feature_node *vectorize(const FingerPrintResultsIPv6 *FPR) {
const char * const IPV6_PROBE_NAMES[] = {"S1", "S2", "S3", "S4", "S5", "S6", "IE1", "IE2", "NS", "U1", "TECN", "T2", "T3", "T4", "T5", "T6", "T7"};
const char * const TCP_PROBE_NAMES[] = {"S1", "S2", "S3", "S4", "S5", "S6", "TECN", "T2", "T3", "T4", "T5", "T6", "T7"};
const char * const ICMPV6_PROBE_NAMES[] = {"IE1", "IE2", "NS"};
unsigned int nr_feature, i, idx;
struct feature_node *features;
std::map<std::string, FPPacket> resps;
for (i = 0; i < NUM_FP_PROBES_IPv6; i++) {
PacketElement *pe;
if (FPR->fp_responses[i] == NULL)
continue;
pe = PacketParser::split(FPR->fp_responses[i]->buf, FPR->fp_responses[i]->len);
assert(pe != NULL);
resps[FPR->fp_responses[i]->probe_id].setPacket(pe);
resps[FPR->fp_responses[i]->probe_id].setTime(&FPR->fp_responses[i]->senttime);
}
nr_feature = get_nr_feature(&FPModel);
features = new feature_node[nr_feature + 1];
for (i = 0; i < nr_feature; i++) {
features[i].index = i + 1;
features[i].value = -1;
}
features[i].index = -1;
idx = 0;
for (i = 0; i < NELEMS(IPV6_PROBE_NAMES); i++) {
const char *probe_name;
probe_name = IPV6_PROBE_NAMES[i];
features[idx++].value = vectorize_plen(resps[probe_name].getPacket());
features[idx++].value = vectorize_tc(resps[probe_name].getPacket());
features[idx++].value = vectorize_hlim(resps[probe_name].getPacket(), FPR->distance, FPR->distance_calculation_method);
}
/* TCP features */
features[idx++].value = vectorize_isr(resps);
for (i = 0; i < NELEMS(TCP_PROBE_NAMES); i++) {
const char *probe_name;
const TCPHeader *tcp;
u16 flags;
u16 mask;
unsigned int j;
int mss;
int sackok;
int wscale;
probe_name = TCP_PROBE_NAMES[i];
mss = -1;
sackok = -1;
wscale = -1;
tcp = find_tcp(resps[probe_name].getPacket());
if (tcp == NULL) {
/* 49 TCP features. */
idx += 49;
continue;
}
features[idx++].value = tcp->getWindow();
flags = tcp->getFlags16();
for (mask = 0x001; mask <= 0x800; mask <<= 1)
features[idx++].value = (flags & mask) != 0;
for (j = 0; j < 16; j++) {
nping_tcp_opt_t opt;
opt = tcp->getOption(j);
if (opt.value == NULL)
break;
features[idx++].value = opt.type;
/* opt.len includes the two (type, len) bytes. */
if (opt.type == TCPOPT_MSS && opt.len == 4 && mss == -1)
mss = ntohs(*(u16 *) opt.value);
else if (opt.type == TCPOPT_SACKOK && opt.len == 2 && sackok == -1)
sackok = 1;
else if (opt.type == TCPOPT_WSCALE && opt.len == 3 && wscale == -1)
wscale = *(u8 *) opt.value;
}
for (; j < 16; j++)
idx++;
for (j = 0; j < 16; j++) {
nping_tcp_opt_t opt;
opt = tcp->getOption(j);
if (opt.value == NULL)
break;
features[idx++].value = opt.len;
}
for (; j < 16; j++)
idx++;
features[idx++].value = mss;
features[idx++].value = sackok;
features[idx++].value = wscale;
if (mss != 0 && mss != -1)
features[idx++].value = (float)tcp->getWindow() / mss;
else
features[idx++].value = -1;
}
/* ICMPv6 features */
for (i = 0; i < NELEMS(ICMPV6_PROBE_NAMES); i++) {
const char *probe_name;
probe_name = ICMPV6_PROBE_NAMES[i];
features[idx++].value = vectorize_icmpv6_type(resps[probe_name].getPacket());
features[idx++].value = vectorize_icmpv6_code(resps[probe_name].getPacket());
}
assert(idx == nr_feature);
if (o.debugging > 2) {
log_write(LOG_PLAIN, "v = {");
for (i = 0; i < nr_feature; i++)
log_write(LOG_PLAIN, "%.16g, ", features[i].value);
log_write(LOG_PLAIN, "};\n");
}
return features;
}
static void apply_scale(struct feature_node *features, unsigned int num_features,
const double (*scale)[2]) {
unsigned int i;
for (i = 0; i < num_features; i++) {
double val = features[i].value;
if (val < 0)
continue;
val = (val + scale[i][0]) * scale[i][1];
features[i].value = val;
}
}
/* (label, prob) pairs for purpose of sorting. */
struct label_prob {
int label;
double prob;
};
int label_prob_cmp(const void *a, const void *b) {
const struct label_prob *la, *lb;
la = (struct label_prob *) a;
lb = (struct label_prob *) b;
/* Sort descending. */
if (la->prob > lb->prob)
return -1;