winPcap_3_获取设备列表

获取设备列表

int pcap_findalldevs_ex  (
    char *  source,
    //The 'source' is a parameter that tells the function where the lookup has to be done and it uses the same syntax of the pcap_open().
    //This source will be examined looking for adapters (local or remote) (e.g. source can be 'rpcap://' for local adapters or 'rpcap://host:port' for adapters on a remote host) or pcap files (e.g. source can be 'file://c:/myfolder/').
    struct pcap_rmtauth *  auth,
    //auth,:  a pointer to a pcap_rmtauth structure. This pointer keeps the information required to authenticate the RPCAP connection to the remote host. This parameter is not meaningful in case of a query to the local host: in that case it can be NULL. 
    pcap_if_t **  alldevs,
    //alldevs,:  a 'struct pcap_if_t' pointer, which will be properly allocated inside this function. When the function returns, it is set to point to the first element of the interface list; each element of the list is of type 'struct pcap_if_t'. 
    char *  errbuf
    //errbuf,:  a pointer to a user-allocated buffer (of size PCAP_ERRBUF_SIZE) that will contain the error message (in case there is one). 
)

　　·功能：获得已连接的网络适配器列表；(Create a list of network devices that can be opened with pcap_open(). )

　　·该函数返回一个 pcap_if 结构的链表， 每个这样的结构都包含了一个适配器的详细信息；

　　·pcap_if结构链表中：数据域 name 和 description 表示一个适配器名称和一个可以让人们理解的描述；

　　·errbuf：一旦发生错误，这个参数将会被libpcap写入字符串类型的错误信息；

Returns:

'0' if everything is fine, '-1' if some errors occurred. The list of the devices is returned in the 'alldevs' variable. When the function returns correctly, 'alldevs' cannot be NULL. In other words, this function returns '-1' also in case the system does not have any interface to list.

The error message is returned in the 'errbuf' variable. An error could be due to several reasons:

• libpcap/WinPcap was not installed on the local/remote host
• the user does not have enough privileges to list the devices / files
• a network problem
• the RPCAP version negotiation failed
• other errors (not enough memory and others).

Warning:

There may be network devices that cannot be opened with pcap_open() 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.

The interface list must be deallocated manually by using the pcap_freealldevs().  

struct pcap_rmtauth{
　　int    type
     //Type of the authentication required.
　　char *    username
     //Zero-terminated string containing the username that has to be used on the remote machine for authentication.
　　char *    password
     //Zero-terminated string containing the password that has to be used on the remote machine for authentication. 
};
 

typedef struct pcap_if pcap_if_t;

struct  pcap_if
{
    pcap_if *    next
    //if not NULL, a pointer to the next element in the list; NULL for the last element of the list
    char *    name
    //a pointer to a string giving a name for the device to pass to pcap_open_live()
    char *    description
    //if not NULL, a pointer to a string giving a human-readable description of the device
    pcap_addr *    addresses
    //a pointer to the first element of a list of addresses for the interface
    u_int    flags
    //PCAP_IF_ interface flags. Currently the only possible flag is PCAP_IF_LOOPBACK, that is set if the interface is a loopback interface.
};

typedef struct pcap_addr pcap_addr_t;

struct  pcap_addr
{
    pcap_addr *    next
    //if not NULL, a pointer to the next element in the list; NULL for the last element of the list
    sockaddr *    addr
    //a pointer to a struct sockaddr containing an address
    sockaddr *    netmask
    //if not NULL, a pointer to a struct sockaddr that contains the netmask corresponding to the address pointed to by addr.
    sockaddr *    broadaddr
    //if not NULL, a pointer to a struct sockaddr that contains the broadcast address corre­ sponding to the address pointed to by addr; may be null if the interface doesn't support broadcasts
    sockaddr *    dstaddr
    //if not NULL, a pointer to a struct sockaddr that contains the destination address corre­ sponding to the address pointed to by addr; may be null if the interface isn't a point- to-point interface
};

void pcap_freealldevs  ( pcap_if_t *  alldevsp   )   

　　·功能：Free an interface list returned by pcap_findalldevs().（pcap_freealldevs() is used to free a list allocated by pcap_findalldevs().）

#include "pcap.h"

main()
{
    pcap_if_t *alldevs;
    pcap_if_t *d;
    int i=0;
    char errbuf[PCAP_ERRBUF_SIZE];
    
    /* 获取本地机器设备列表 */
    if (pcap_findalldevs_ex(PCAP_SRC_IF_STRING, NULL /* auth is not needed */, &alldevs, errbuf) == -1)
    {
        fprintf(stderr,"Error in pcap_findalldevs_ex: %s
", errbuf);
        exit(1);
    }
    
    /* 打印列表 */
    for(d= alldevs; d != NULL; d= d->next)
    {
        printf("%d. %s", ++i, d->name);
        if (d->description)
            printf(" (%s)
", d->description);
        else
            printf(" (No description available)
");
    }
    
    if (i == 0)
    {
        printf("
No interfaces found! Make sure WinPcap is installed.
");
        return;
    }

    /* 不再需要设备列表了，释放它 */
    pcap_freealldevs(alldevs);
}

　　编译：在Windows平台上，您需要创建一个工程，并按照 使用WinPcap编程 里的步骤做。 然而，我们建议您使用WinPcap developer's pack ( 详情请访问WinPcap网站, http://www.winpcap.org ), 因为它提供了很多已经配置好的范例，包括本教程中的所有示例代码，以及在编译运行时需要的 包含文件(include) 和 库(libraries)

　　结果：

　　前部分为name，后面部分为description；