/*************************************************************************** * 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) 1996-2022 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.com) 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/ * * * ***************************************************************************/ /* $Id$ */ #ifndef __FPENGINE_H__ #define __FPENGINE_H__ 1 #include "nsock.h" #include #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 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 &Targets) = 0; const char *bpf_filter(std::vector &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 fphosts; /* Information about each target to fingerprint */ public: FPEngine6(); ~FPEngine6(); void reset(); int os_scan(std::vector &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 load_fp_matches(); #endif /* __FPENGINE_H__ */