1

到目前为止，这是我的代码。


#include <stdio.h>
#include <stdlib.h>
#include <pcap.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(int & argc, char* argv[]){


    char *net; /* dot notation of the network address */
    char *mask;/* dot notation of the network mask    */
    int ret;   /* return code */
    char errbuf[PCAP_ERRBUF_SIZE];
    bpf_u_int32 netp; /* ip          */
    bpf_u_int32 maskp;/* subnet mask */
    struct in_addr addr;

    char *dev; /* name of the device to use */

    printf("Asking pcap to find a valid device for use to sniff on.\n");
    dev = pcap_lookupdev(errbuf);
    if(dev == NULL) {
        printf("pcap_lookupdev ERROR:  %s\n",errbuf);
        exit(1);
    }

    printf("Printing out device name.\n");
    printf("DEV: %s\n",dev);

    printf("Asking pcap for the network address and mask of the device.\n");
    ret = pcap_lookupnet(dev,&netp,&maskp,errbuf);
    if(ret == -1) {
        printf("Unable to retrieve the network address and mask of the device.  Error Description:  %s\n",errbuf);
        exit(1);
    }

    printf("Get the network address in a human readable form,\n");
    addr.s_addr = netp;
    net = inet_ntoa(addr);
    if(net == NULL) {
        printf("Unable to retrieve network address in human readable form.\n");
        perror("inet_ntoa");
        exit(1);
    }

    printf("NET: %s\n",net);

    /* do the same as above for the device's mask */
    addr.s_addr = maskp;
    mask = inet_ntoa(addr);

    if(mask == NULL) {
        printf("Unable to retrieve device mask in human readable form.  ");
        perror("inet_ntoa");
        exit(1);
    }

    printf("MASK: %s\n",mask);
    return 0;
}

/*
Output:

Asking pcap to find a valid device for use to sniff on.
Printing out device name.
DEV: eth0
Asking pcap for the network address and mask of the device.
Unable to retrieve the network address and mask of the device.  Error Description:  eth0: no IPv4 address assigned

*/

这是我的问题：我需要做什么才能让 pcap_lookupdev 查找无线设备（即 wlan0）？

4

2 回答 2

2

The documentation for pcap_findalldevs hints at the reason why pcap_lookupdev() is not finding any suitable network devices:

Note that there may be network devices that cannot be opened with pcap_open_live() by the process calling pcap_findalldevs(), because, for example, that process might not have sufficient privileges to open them for capturing; if so, those devices will not appear on the list

You probably don't have the necessary permission to capture traffic on any of the available network devices. Try running your program with sudo, assuming you have admin privileges on your machine.

See requirement of root privileges for libpcap functions for additional information.

于 2011-08-10T19:40:17.303 回答
0

pcap_lookupdev()将查找一台设备。那可能不是您想要的设备；如果您同时拥有有线和无线接口设备，它很可能会找到有线设备，这不是因为它没有查看无线设备，而是因为它恰好是它找到的第一个设备。

没有办法告诉它只查看无线设备。

要获取libpcap 可以处理的所有pcap_findalldevs()设备的列表，请使用.

于 2012-10-19T20:44:58.160 回答