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/***************************************************************************
* FPEngine.h -- Header info for IPv6 OS detection via TCP/IP *
* fingerprinting. For more information on how this works in Nmap, see *
* http://insecure.org/osdetect/ *
* *
***********************IMPORTANT NMAP LICENSE TERMS************************
* *
* The Nmap Security Scanner is (C) 1996-2021 Nmap Software 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. *
* *
***************************************************************************/
/* $Id$ */
#ifndef __FPENGINE_H__
#define __FPENGINE_H__ 1
#include "nsock.h"
#include <vector>
#include "libnetutil/npacket.h"
/* Mention some classes here so we don't have to place the declarations in
* the right order (otherwise the compiler complains). */
class FPHost;
class FPHost6;
class FPProbe;
class Target;
class FingerPrintResultsIPv6;
struct FingerMatch;
/******************************************************************************
* CONSTANT DEFINITIONS *
******************************************************************************/
#define NELEMS(a) (sizeof(a) / sizeof((a)[0]))
#define NUM_FP_PROBES_IPv6_TCP 13
#define NUM_FP_PROBES_IPv6_ICMPv6 4
#define NUM_FP_PROBES_IPv6_UDP 1
/* Total number of IPv6 OS detection probes. */
#define NUM_FP_PROBES_IPv6 (NUM_FP_PROBES_IPv6_TCP+NUM_FP_PROBES_IPv6_ICMPv6+NUM_FP_PROBES_IPv6_UDP)
/* Even with a successful classification, we may not consider a match good if it
is too different from other members of the class. */
#define FP_NOVELTY_THRESHOLD 15.0
const unsigned int OSDETECT_FLOW_LABEL = 0x12345;
/* Number of timed probes for IPv6 OS scan. This is, the number of probes that
* have specific timing requirements and need to be processed together. This
* are the probes that are sent 100ms apart. */
#define NUM_FP_TIMEDPROBES_IPv6 6
/* Initial congestion window. It is set to the number of timed probes because
* hosts need to be able to schedule all of them at once. */
#define OSSCAN_INITIAL_CWND (NUM_FP_TIMEDPROBES_IPv6)
/* Initial Slow Start threshold. It is set to four times the initial CWND. */
#define OSSCAN_INITIAL_SSTHRESH (4 * OSSCAN_INITIAL_CWND)
/* Host group size is the number of osscan hosts that are processed in parallel.
* Note that this osscan engine always keeps a working group of this many hosts.
* in other words, if one host in the group finishes, another is added to it
* dynamically. */
#define OSSCAN_GROUP_SIZE 10
/* Initial retransmission timeout. This is the time we initially wait for a
* probe response before retransmitting the original probe. Note that this is
* only the initial RTO, used only when no RTT measures have been taken yet.
* The actual RTO varies each time we get a response to a probe.
* It is set to 3 seconds (3*10^6 usecs) as per RFC 2988. */
#define OSSCAN_INITIAL_RTO (3*1000000)
/******************************************************************************
* CLASS DEFINITIONS *
******************************************************************************/
/* This class handles the access to the network. It handles packet transmission
* scheduling, packet capture and congestion control. Every FPHost should be
* linked to the same instance of this class, so the access to the network can
* be managed globally (for the whole OS detection process). */
class FPNetworkControl {
private:
nsock_pool nsp; /* Nsock pool. */
nsock_iod pcap_nsi; /* Nsock Pcap descriptor. */
nsock_event_id pcap_ev_id; /* Last pcap read event that was scheduled. */
bool first_pcap_scheduled; /* True if we scheduled the first pcap read event. */
bool nsock_init; /* True if the nsock pool has been initialized. */
int rawsd; /* Raw socket. */
std::vector<FPHost *> callers; /* List of users of this instance (used for callbacks).*/
int probes_sent; /* Number of unique probes sent (not retransmissions). */
int responses_recv; /* Number of probe responses received. */
int probes_timedout; /* Number of probes that timeout after all retransms. */
float cc_cwnd; /* Current congestion window. */
float cc_ssthresh; /* Current Slow Start threshold. */
int cc_init();
int cc_update_sent(int pkts);
int cc_report_drop();
int cc_update_received();
public:
FPNetworkControl();
~FPNetworkControl();
void init(const char *ifname, devtype iftype);
int register_caller(FPHost *newcaller);
int unregister_caller(FPHost *oldcaller);
int setup_sniffer(const char *iface, const char *bfp_filter);
void handle_events();
int scheduleProbe(FPProbe *pkt, int in_msecs_time);
void probe_transmission_handler(nsock_pool nsp, nsock_event nse, void *arg);
void response_reception_handler(nsock_pool nsp, nsock_event nse, void *arg);
bool request_slots(size_t num_packets);
int cc_report_final_timeout();
};
/* +-----------+
| FPEngine |
+-----------+
| |
+-----+-----+
|
+-------+-------+
| |
| |
+-----------+ +-----------+
| FPEngine4 | | FPEngine6 |
+-----------+ +-----------+
| | | |
+-----------+ +-----------+ */
/* This class is the generic fingerprinting engine. */
class FPEngine {
protected:
size_t osgroup_size;
public:
FPEngine();
virtual ~FPEngine();
void reset();
virtual int os_scan(std::vector<Target *> &Targets) = 0;
const char *bpf_filter(std::vector<Target *> &Targets);
};
/* This class handles IPv6 OS fingerprinting. Using it is very simple, just
* instance it and then call os_scan() with the list of IPv6 targets to
* fingerprint. If everything goes well, the internal state of the supplied
* target objects will be modified to reflect the results of the fingerprinting
* process. */
class FPEngine6 : public FPEngine {
private:
std::vector<FPHost6 *> fphosts; /* Information about each target to fingerprint */
public:
FPEngine6();
~FPEngine6();
void reset();
int os_scan(std::vector<Target *> &Targets);
};
/* +----------+
| FPPacket |
+----------+
| |
+-----+----+
|
|
+-----------+
| FPProbe |
+-----------+
| |
+-----+-----+ */
/* This class represents a generic packet for the OS fingerprinting process */
class FPPacket {
protected:
PacketElement *pkt; /* Actual packet associated with this FPPacket */
bool link_eth; /* Ethernet layer required? */
struct eth_nfo eth_hdr; /* Eth info, valid when this->link_eth==true */
struct timeval pkt_time; /* Time at which the packet was sent or received */
int resetTime();
void __reset();
public:
FPPacket();
~FPPacket();
int setTime(const struct timeval *tv = NULL);
struct timeval getTime() const;
int setPacket(PacketElement *pkt);
int setEthernet(const u8 *src_mac, const u8 *dst_mac, const char *devname);
const struct eth_nfo *getEthernet() const;
const PacketElement *getPacket() const;
size_t getLength() const;
u8 *getPacketBuffer(size_t *pkt_len) const;
bool is_set() const;
};
/* This class represents a generic OS fingerprinting probe. In other words, it
* represents a network packet that Nmap sends to a target in order to
* obtain information about the target's TCP/IP stack. */
class FPProbe : public FPPacket {
private:
char *probe_id;
int probe_no;
int retransmissions;
int times_replied;
bool failed;
bool timed;
public:
FPHost *host;
FPProbe();
~FPProbe();
void reset();
bool isResponse(PacketElement *rcvd);
int setProbeID(const char *id);
const char *getProbeID() const;
int getRetransmissions() const;
int incrementRetransmissions();
int getReplies() const;
int incrementReplies();
int setTimeSent();
int resetTimeSent();
struct timeval getTimeSent() const;
bool probeFailed() const;
int setFailed();
bool isTimed() const;
int setTimed();
int changeSourceAddress(struct in6_addr *addr);
};
/* This class represents a generic received packet. */
struct FPResponse {
const char *probe_id;
u8 *buf;
size_t len;
struct timeval senttime, rcvdtime;
FPResponse(const char *probe_id, const u8 *buf, size_t len,
struct timeval senttime, struct timeval rcvdtime);
~FPResponse();
};
/* +-----------+
| FPHost |
+-----------+
| |
+-----+-----+
|
+-------+-------+
| |
| |
+-----------+ +-----------+
| FPHost4 | | FPHost6 |
+-----------+ +-----------+
| | | |
+-----------+ +-----------+ */
/* This class represents a generic host to be fingerprinted. */
class FPHost {
protected:
unsigned int total_probes; /* Number of different OS scan probes to be sent to targets */
unsigned int timed_probes; /* Number of probes that have specific timing requirements */
unsigned int probes_sent; /* Number of FPProbes sent (not counting retransmissions) */
unsigned int probes_answered; /* Number of FPResponses received */
unsigned int probes_unanswered; /* Number of FPProbes that timedout (after all retransmissions) */
bool incomplete_fp; /* True if we were unable to send all attempted probes */
bool detection_done; /* True if the OS detection process has been completed. */
bool timedprobes_sent; /* True if the probes that have timing requirements were sent */
Target *target_host; /* Info about the host to fingerprint */
FPNetworkControl *netctl; /* Link to the network manager (for scheduling and CC) */
bool netctl_registered; /* True if we are already registered in the network controller */
u32 tcpSeqBase; /* Base for sequence numbers set in outgoing probes */
int open_port_tcp; /* Open TCP port to be used in the OS detection probes */
int closed_port_tcp; /* Closed TCP port for the OS detection probes. */
int closed_port_udp; /* Closed UDP port. */
int tcp_port_base; /* Send TCP probes starting with this port number. */
int udp_port_base; /* Send UDP probes with this port number. */
u16 icmp_seq_counter; /* ICMPv6 sequence number counter. */
int rto; /* Retransmission timeout for the host */
int rttvar; /* Round-Trip Time variation (RFC 2988) */
int srtt; /* Smoothed Round-Trip Time (RFC 2988) */
void __reset();
int update_RTO(int measured_rtt_usecs, bool retransmission);
int choose_osscan_ports();
private:
virtual int build_probe_list() = 0;
public:
struct timeval begin_time;
FPHost();
virtual ~FPHost();
virtual bool done() = 0;
virtual int schedule() = 0;
virtual int callback(const u8 *pkt, size_t pkt_len, const struct timeval *tv) = 0;
const struct sockaddr_storage *getTargetAddress();
void fail_one_probe();
};
/* This class represents IPv6 hosts to be fingerprinted. The class performs
* OS detection asynchronously. To use it, schedule() must be called at regular
* intervals until done() returns true. After that, status() will indicate
* whether the host was successfully matched with a particular OS or not. */
class FPHost6 : public FPHost {
private:
FPProbe fp_probes[NUM_FP_PROBES_IPv6]; /* OS detection probes to be sent.*/
FPResponse *fp_responses[NUM_FP_PROBES_IPv6]; /* Received responses. */
FPResponse *aux_resp[NUM_FP_TIMEDPROBES_IPv6]; /* Aux vector for timed responses */
int build_probe_list();
int set_done_and_wrap_up();
public:
FPHost6(Target *tgt, FPNetworkControl *fpnc);
~FPHost6();
void reset();
void init(Target *tgt, FPNetworkControl *fpnc);
void finish();
bool done();
int schedule();
int callback(const u8 *pkt, size_t pkt_len, const struct timeval *tv);
const FPProbe *getProbe(const char *id);
const FPResponse *getResponse(const char *id);
void fill_FPR(FingerPrintResultsIPv6 *FPR);
};
/******************************************************************************
* Nsock handler wrappers. *
******************************************************************************/
void probe_transmission_handler_wrapper(nsock_pool nsp, nsock_event nse, void *arg);
void response_reception_handler_wrapper(nsock_pool nsp, nsock_event nse, void *arg);
std::vector<FingerMatch> load_fp_matches();
#endif /* __FPENGINE_H__ */