/* Dynamically load libpcap at runtime This library optionally loads the 'libpcap' library at runtime, rather than statically linked at compile time. The advantage of this is that the user can build this project with no dependencies -- although they may require this dependency in order to run the program. As of 2017, libpcap shared libraries are standard on major Linux distributions (Debian, Readhat), FreeBSD, OpenBSD, and macOS. On Windows, "winpcap" must be downloaded. */ #ifndef STUB_PCAP_H #define STUB_PCAP_H #include /* Including the right ".h" file to define "timeval" is difficult, so instead * so instead we are simply going to define our own structure. This should * match the binary definition within the operating system */ #if __NetBSD__ #include #define pcap_timeval timeval #elif __OpenBSD__ #include #define pcap_timeval bpf_timeval #else struct pcap_timeval { long tv_sec; /* seconds */ long tv_usec; /* and microseconds */ }; #endif /* Forward reference of opaque 'pcap_t' structure */ struct pcap; typedef struct pcap pcap_t; /* Forward reference of opaque 'pcap_if_t' structure */ struct pcap_if; typedef struct pcap_if pcap_if_t; /* How many bytes to reserve for error messages. This is the number specified * in libpcap, smaller numbers can crash */ enum { PCAP_ERRBUF_SIZE=256, }; /* used in pcap_setdirection() */ typedef enum { PCAP_D_INOUT = 0, PCAP_D_IN = 1, PCAP_D_OUT = 2, } pcap_direction_t; enum { PCAP_ERROR = -1, PCAP_ERROR_BREAK = -2, PCAP_ERROR_NOT_ACTIVATED = -3, PCAP_ERROR_ACTIVATED = -4, PCAP_ERROR_NO_SUCH_DEVICE = -5, PCAP_ERROR_RFMON_NOTSUP = -6, PCAP_ERROR_NOT_RFMON = -7, PCAP_ERROR_PERM_DENIED = -8, PCAP_ERROR_IFACE_NOT_UP = -9, PCAP_ERROR_CANTSET_TSTAMP_TYPE = -10, PCAP_ERROR_PROMISC_PERM_DENIED = -11, PCAP_ERROR_TSTAMP_PRECISION_NOTSUP = -12, /* warnings, not errors */ PCAP_WARNING = 1, PCAP_WARNING_PROMISC_NOTSUP = 2, PCAP_WARNING_TSTAMP_TYPE_NOTSUP = 3, }; /* The packet header for capturing packets. Apple macOS inexplicably adds * an extra comment-field onto the end of this, so the definition needs * to be careful to match the real definition */ struct pcap_pkthdr { struct pcap_timeval ts; unsigned caplen; unsigned len; #ifdef __APPLE__ char comment[256]; #endif }; /* * This block is for function declarations. Consult the libpcap * documentation for what these functions really mean */ typedef void (*PCAP_HANDLE_PACKET)(unsigned char *v_seap, const struct pcap_pkthdr *framehdr, const unsigned char *buf); typedef void (*PCAP_CLOSE)(void *hPcap); typedef unsigned (*PCAP_DATALINK)(void *hPcap); typedef unsigned (*PCAP_DISPATCH)(void *hPcap, unsigned how_many_packets, PCAP_HANDLE_PACKET handler, void *handle_data); typedef int (*PCAP_FINDALLDEVS)(pcap_if_t **alldevs, char *errbuf); typedef const char *(*PCAP_LIB_VERSION)(void); typedef char * (*PCAP_LOOKUPDEV)(char *errbuf); typedef int (*PCAP_MAJOR_VERSION)(void *p); typedef int (*PCAP_MINOR_VERSION)(void *p); typedef void * (*PCAP_OPEN_LIVE)(const char *devicename, unsigned snap_length, unsigned is_promiscuous, unsigned read_timeout, char *errbuf); typedef void (*PCAP_FREEALLDEVS)(pcap_if_t *alldevs); typedef pcap_t * (*PCAP_OPEN_OFFLINE)(const char *fname, char *errbuf); typedef int (*PCAP_SENDPACKET)(pcap_t *p, const unsigned char *buf, int size); typedef const unsigned char *(*PCAP_NEXT)(pcap_t *p, struct pcap_pkthdr *h); typedef int (*PCAP_SETDIRECTION)(pcap_t *, pcap_direction_t); typedef const char *(*PCAP_DATALINK_VAL_TO_NAME)(int dlt); typedef void (*PCAP_PERROR)(pcap_t *p, char *prefix); typedef const char *(*PCAP_GETERR)(pcap_t *p); typedef const char *(*PCAP_DEV_NAME)(const pcap_if_t *dev); typedef const char *(*PCAP_DEV_DESCRIPTION)(const pcap_if_t *dev); typedef const pcap_if_t *(*PCAP_DEV_NEXT)(const pcap_if_t *dev); /* pcap_open() replaced with a series of calls to: p = pcap_create(device, errbuf); pcap_set_snaplen(p, snaplen); pcap_set_promisc(p, promisc); pcap_set_timeout(p, to_ms); pcap_activate(p); */ typedef pcap_t *(*PCAP_CREATE)(const char *source, char *errbuf); typedef int (*PCAP_SET_SNAPLEN)(pcap_t *p, int snaplen); typedef int (*PCAP_SET_PROMISC)(pcap_t *p, int promisc); typedef int (*PCAP_SET_TIMEOUT)(pcap_t *p, int to_ms); typedef int (*PCAP_SET_IMMEDIATE_MODE)(pcap_t *p, int immediate_mode); typedef int (*PCAP_SET_BUFFER_SIZE)(pcap_t *p, int buffer_size); typedef int (*PCAP_SET_RFMON)(pcap_t *p, int rfmon); typedef int (*PCAP_CAN_SET_RFMON)(pcap_t *p); typedef int (*PCAP_ACTIVATE)(pcap_t *p); /* * PORTABILITY: Windows supports the "sendq" feature, and is really slow * without this feature. It's not needed on Linux, so we just create * equivalent functions that do nothing */ struct pcap_send_queue; typedef struct pcap_send_queue pcap_send_queue; typedef pcap_send_queue *(*PCAP_SENDQUEUE_ALLOC)(size_t size); typedef unsigned (*PCAP_SENDQUEUE_TRANSMIT)(pcap_t *p, pcap_send_queue *queue, int sync); typedef void (*PCAP_SENDQUEUE_DESTROY)(pcap_send_queue *queue); typedef int (*PCAP_SENDQUEUE_QUEUE)(pcap_send_queue *queue, const struct pcap_pkthdr *pkt_header, const unsigned char *pkt_data); struct PcapFunctions { unsigned func_err:1; unsigned is_available:1; unsigned is_printing_debug:1; unsigned status; unsigned errcode; PCAP_CLOSE close; PCAP_DATALINK datalink; PCAP_DISPATCH dispatch; PCAP_FINDALLDEVS findalldevs; PCAP_FREEALLDEVS freealldevs; PCAP_LOOKUPDEV lookupdev; PCAP_LIB_VERSION lib_version; PCAP_MAJOR_VERSION major_version; PCAP_MINOR_VERSION minor_version; PCAP_OPEN_LIVE open_live; PCAP_OPEN_OFFLINE open_offline; PCAP_SENDPACKET sendpacket; PCAP_NEXT next; PCAP_SETDIRECTION setdirection; PCAP_DATALINK_VAL_TO_NAME datalink_val_to_name; PCAP_PERROR perror; PCAP_GETERR geterr; /* Accessor functions for opaque data structure, don't really * exist in libpcap */ PCAP_DEV_NAME dev_name; PCAP_DEV_DESCRIPTION dev_description; PCAP_DEV_NEXT dev_next; /* Windows-only functions */ PCAP_SENDQUEUE_ALLOC sendqueue_alloc; PCAP_SENDQUEUE_TRANSMIT sendqueue_transmit; PCAP_SENDQUEUE_DESTROY sendqueue_destroy; PCAP_SENDQUEUE_QUEUE sendqueue_queue; PCAP_CREATE create; PCAP_SET_SNAPLEN set_snaplen; PCAP_SET_PROMISC set_promisc; PCAP_SET_TIMEOUT set_timeout; PCAP_SET_IMMEDIATE_MODE set_immediate_mode; PCAP_SET_BUFFER_SIZE set_buffer_size; PCAP_SET_RFMON set_rfmon; PCAP_CAN_SET_RFMON can_set_rfmon; PCAP_ACTIVATE activate; }; /** * This is global structure containing all the libpcap function pointers. * use in the form "PCAP.functionname()" rather than "pcap_functioname()". */ extern struct PcapFunctions PCAP; /** * Dynamically loads the shared library (libpcap.so, libpcap.dynlib, * or libpcap.dll. Call this during program startup like main() in order * to load the libraries. Not thread safe, so call from the startup * thread, but not within threads. * @return * 0 on success or * -1 on failure */ int pcap_init(void); #endif