pcap_wrapper.cpp

#include <windows.h>
#include <pcap_wrapper.h>
#include <assert.h>
#include <stdio.h>
int (*pcap_loop)(pcap_t *, int, pcap_handler, u_char *);
int (*pcap_breakloop)(pcap_t *);

pcap_t *(*pcap_create)(const char *, char *);

int (*pcap_set_snaplen)(pcap_t *, int) = 0;
int (*pcap_set_promisc)(pcap_t *, int) = 0;
int (*pcap_can_set_rfmon)(pcap_t *) = 0;
int (*pcap_set_rfmon)(pcap_t *, int) = 0;
int (*pcap_set_timeout)(pcap_t *, int) = 0;
int (*pcap_set_buffer_size)(pcap_t *, int) = 0;
int (*pcap_activate)(pcap_t *) = 0;

int (*pcap_setfilter)(pcap_t *, struct bpf_program *) = 0;
int (*pcap_setdirection)(pcap_t *, pcap_direction_t) = 0;

int (*pcap_datalink)(pcap_t *) = 0;

void (*pcap_freecode)(struct bpf_program *) = 0;

int (*pcap_compile)(pcap_t *, struct bpf_program *, const char *, int,
                    bpf_u_int32) = 0;

char *(*pcap_geterr)(pcap_t *) = 0;
int (*pcap_sendpacket)(pcap_t *, const u_char *, int) = 0;

char *(*pcap_lookupdev)(char *) = 0;

int (*pcap_findalldevs)(pcap_if_t **, char *) = 0;

struct init_pcap_t {
    init_pcap_t() {
        init_pcap();
    }

} do_it;

static void init_npcap_dll_path() {
    BOOL(WINAPI * SetDllDirectory)
    (LPCTSTR);
    char sysdir_name[512];
    int len;

    SetDllDirectory = (BOOL(WINAPI *)(LPCTSTR))GetProcAddress(GetModuleHandle("kernel32.dll"), "SetDllDirectoryA");
    if (SetDllDirectory == NULL) {
        printf("Error in SetDllDirectory\n");
    } else {
        len = GetSystemDirectory(sysdir_name, 480);  //	be safe
        if (!len)
            printf("Error in GetSystemDirectory (%d)\n", (int)GetLastError());
        strcat(sysdir_name, "\\Npcap");
        if (SetDllDirectory(sysdir_name) == 0)
            printf("Error in SetDllDirectory(\"System32\\Npcap\")\n");
    }
}

#define EXPORT_FUN(XXX)                                     \
    do {                                                    \
        XXX = (__typeof__(XXX))GetProcAddress(wpcap, #XXX); \
    } while (0)
int init_pcap() {
    HMODULE wpcap = LoadLibrary("wpcap.dll");
    if (wpcap != 0) {
        printf("using system32/wpcap.dll\n");
    } else {
        init_npcap_dll_path();
        // SetDllDirectory("C:\\Windows\\System32\\Npcap\\");
        wpcap = LoadLibrary("wpcap.dll");
        if (wpcap != 0)
            printf("using system32/npcap/wpcap.dll\n");
    }
    if (wpcap == 0) {
        printf("cant not open wpcap.dll, make sure winpcap/npcap is installed\n");
        exit(-1);
    }
    assert(wpcap != 0);

    EXPORT_FUN(pcap_loop);
    EXPORT_FUN(pcap_breakloop);
    EXPORT_FUN(pcap_create);
    EXPORT_FUN(pcap_set_snaplen);
    EXPORT_FUN(pcap_set_promisc);
    EXPORT_FUN(pcap_set_timeout);
    EXPORT_FUN(pcap_activate);
    EXPORT_FUN(pcap_setfilter);
    EXPORT_FUN(pcap_setdirection);
    EXPORT_FUN(pcap_datalink);
    EXPORT_FUN(pcap_freecode);
    EXPORT_FUN(pcap_compile);
    EXPORT_FUN(pcap_geterr);
    EXPORT_FUN(pcap_sendpacket);
    EXPORT_FUN(pcap_lookupdev);
    EXPORT_FUN(pcap_findalldevs);
    /*
    pcap_loop = (__typeof__(pcap_loop))GetProcAddress(wpcap, "pcap_loop");
    pcap_create = (__typeof__(pcap_create))GetProcAddress(wpcap, "pcap_create");
    pcap_set_snaplen = (__typeof__(pcap_set_snaplen))GetProcAddress(wpcap, "pcap_set_snaplen");
    pcap_set_promisc = (__typeof__(pcap_set_promisc))GetProcAddress(wpcap, "pcap_set_promisc");
    pcap_set_timeout = (__typeof__(pcap_set_timeout))GetProcAddress(wpcap, "pcap_set_timeout");
    pcap_activate = (__typeof__(pcap_activate))GetProcAddress(wpcap, "pcap_activate");
    pcap_setfilter = (__typeof__(pcap_setfilter))GetProcAddress(wpcap, "pcap_setfilter");
    pcap_setdirection = (__typeof__(pcap_setdirection))GetProcAddress(wpcap, "pcap_setdirection");
    pcap_datalink = (__typeof__(pcap_datalink))GetProcAddress(wpcap, "pcap_datalink");
    pcap_freecode = (__typeof__(pcap_freecode))GetProcAddress(wpcap, "pcap_freecode");
    pcap_compile = (__typeof__(pcap_compile))GetProcAddress(wpcap, "pcap_compile");
    pcap_geterr = (__typeof__(pcap_geterr))GetProcAddress(wpcap, "pcap_geterr");
    pcap_sendpacket = (__typeof__(pcap_sendpacket))GetProcAddress(wpcap, "pcap_sendpacket");
    pcap_lookupdev = (__typeof__(pcap_lookupdev))GetProcAddress(wpcap, "pcap_lookupdev");
    pcap_findalldevs = (__typeof__(pcap_findalldevs))GetProcAddress(wpcap, "pcap_findalldevs");
    //pcap_loop = (__typeof__(pcap_loop))GetProcAddress(wpcap, "pcap_loop");
    //pcap_loop = (__typeof__(pcap_loop))GetProcAddress(wpcap, "pcap_loop");
    //pcap_loop = (__typeof__(pcap_loop))GetProcAddress(wpcap, "pcap_loop");
    */
    return 0;
}