Question

使用Getting essid via ioctl in ruby作为模板我想获得BSSID而不是ESSID。但是，不是C开发人员，有一些我不理解的事情。

到目前为止我所做的不工作:( ...

注意我有点困惑，因为根据wireless.h中的一些评论，我认为BSSID只能通过ioctl 设置。但是，存在获取的ioctl。这与我几乎完全缺乏对更中间的C类型主义（结构，联合和东西;））的理解，我根本就不知道。

def _get_bssid(interface)
    # Copied from wireless.h
    # supposing a 16 byte address and 32 byte buffer but I'm totally 
    # guessing here.
    iwreq = [interface, '' * 48,0].pack('a*pI') 
    sock = Socket.new(Socket::AF_INET, Socket::SOCK_DGRAM, 0)

    # from wireless.h
    # SIOCGIWAP 0x8B15      /* get access point MAC addresses */
    sock.ioctl('0x8B15', iwreq) # always get an error: Can't convert string to Integer

    puts iwreq.inspect
end

所以，与此同时，我正在使用wpa_cli方法来获取BSSID，但我更喜欢使用IOCTL：

def _wpa_status(interface)
    wpa_data = nil

    unless interface.nil?
        # need to write a method to get the src_sock_path 
        # programmatically. Fortunately, for me
        # this is going to be the correct sock path 99% of the time.
        # Ideas to get programmatically would be:
        # parse wpa_supplicant.conf
        # check process table | grep wpa_suppl | parse arguments
        src_sock_path  = '/var/run/wpa_supplicant/' + interface
    else
        return nil
    end

    client_sock_path = '/var/run/hwinfo_wpa'

    # open Domain socket
    socket = Socket.new(Socket::AF_UNIX, Socket::SOCK_DGRAM, 0)

    begin
        # bind client domain socket
        socket.bind(Socket.pack_sockaddr_un(client_sock_path))

        # connect to server with our client socket
        socket.connect(Socket.pack_sockaddr_un(src_sock_path))

        # send STATUS command
        socket.send('STATUS', 0)

        # receive 1024 bytes (totally arbitrary value)
        # split lines by \n
        # store in variable wpa_data.
        wpa_data = socket.recv(1024)
    rescue => e
        $stderr.puts 'WARN: unable to gather wpa data: ' + e.inspect
    end
    # close or next time we attempt to read it will fail.
    socket.close

    begin
        # remove the domain socket file for the client
        File.unlink(client_sock_path)
    rescue => e
        $stderr.puts 'WARN: ' + e.inspect
    end

    unless wpa_data.nil?
        @wifis = Hash[wpa_data.split(/\n/).map\
                 {|line|
                    # first, split into pairs delimited by '='
                    key,value = line.split('=')

                    # if key is camel-humped then put space in front
                    # of capped letter
                    if key =~ /[a-z][A-Z]/
                        key.gsub!(/([a-z])([A-Z])/,'\\1_\\2')
                    end

                    # if key is "id" then rename it.
                    key.eql?('id') && key = 'wpa_id'

                    # fix key so that it can be used as a table name
                    # by replacing spaces with underscores
                    key.gsub!(' ','_')

                    # lower case it.
                    key.downcase!

                    [key,value]
                 }]
    end
end

编辑：到目前为止，没有人能够回答这个问题。我认为我更喜欢wpa方法，因为我从中获取更多数据。也就是说，我想提出的一个问题是，如果有人使用wpa代码，请注意它需要升级的权限才能读取wlan套接字。

EDIT ^ 2（完整代码段）：感谢@dasup我已经能够将我的类重新分配到正确使用系统ioctls拉出bssid和essids。（YMMV给出了Linux发行版的实现，年龄和任何其他可能的不稳定因素 - 以下代码片段与3.2和3.7内核一起使用。）

require 'socket'

class Wpa
    attr_accessor :essid, :bssid, :if

    def initialize(interface)
        @if = interface

        puts 'essid: ' + _get_essid.inspect
        puts 'bssid: ' + _get_bssid.inspect
    end

    def _get_essid
        # Copied from wireless.h
        iwreq = [@if, " " * 32, 32, 0 ].pack('a16pII')

        sock = Socket.new(Socket::AF_INET, Socket::SOCK_DGRAM, 0)
        sock.ioctl(0x8B1B, iwreq)

        @essid = iwreq.unpack('@16p').pop.strip
    end 

    def _get_bssid
        # Copied from wireless.h
        # supposing a 16 byte address and 32 byte buffer but I'm totally 
        # guessing here.
        iwreq = [@if, "\0" * 32].pack('a16a32') 
        sock = Socket.new(Socket::AF_INET, Socket::SOCK_DGRAM, 0)

        # from wireless.h
        # SIOCGIWAP 0x8B15      /* get access point MAC addresses */
        sock.ioctl(0x8B15, iwreq) # always get an error: Can't convert string to Integer

        @bssid = iwreq.unpack('@18H2H2H2H2H2H2').join(':')
    end
end

h = Wpa.new('wlan0')

Answer 1

我对Ruby并不是很熟悉，但我发现了两个错误：

SIOCGIWAP的十六进制数应该不带引号/刻度。
数据缓冲区的初始化以接口名称后面的一些尾随字节结束（使用gdb调试）。下面给出的初始化有效。

请注意，如果任何数据结构或常量发生更改，您的代码将会中断（IFNAMSIZ，sa_family，struct sockaddr等）。但是，我认为不会很快发生此类更改。

require 'socket'

def _get_bssid(interface)
    # Copied from wireless.h
    # supposing a 16 byte address and 32 byte buffer but I'm totally 
    # guessing here.
    iwreq = [interface, "\0" * 32].pack('a16a32') 
    sock = Socket.new(Socket::AF_INET, Socket::SOCK_DGRAM, 0)

    # from wireless.h
    # SIOCGIWAP 0x8B15      /* get access point MAC addresses */
    sock.ioctl(0x8B15, iwreq) # always get an error: Can't convert string to Integer

    puts iwreq.inspect
end

你将获得一个数组/缓冲区：

您发送的接口名称，填充0x00个字节，总长度为16个字节。
后跟一个struct sockaddr，即一个双字节标识符0x01 0x00（来自ARPHRD_ETHER？），后跟填充0x00字节的BSSID，总长度为14个字节。

祝你好运！

使用Ruby和ioctl以编程方式获取wifi BSSID

1 个答案: