c - 列出以太网 USB 适配器接口(interface)

Question

我需要一个列出以太网 USB 适配器接口(interface)的 C 函数。在互联网上进行一些搜索后，我在 ubuntu 16.04 中创建了以下小代码:

#include <stdio.h>
#include <stdlib.h>
/* The following include files for the network interface. */
#include <sys/types.h>
#include <sys/socket.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if_types.h>
/* For "toupper". */
#include <ctype.h>
/* For "strerror". */
#include <string.h>
/* For "errno". */
#include <errno.h>

int main() {
        struct ifaddrs *addrs,*tmp;

        getifaddrs(&addrs);
        tmp = addrs;
        struct sockaddr_dl * sdl;

        while (tmp)
        {
            if (tmp->ifa_addr && tmp->ifa_addr->sa_family == AF_PACKET)
                printf("%s\n", tmp->ifa_name);

            tmp = tmp->ifa_next;
            sdl = (struct sockaddr_dl *) tmp->ifa_addr;
            if (sdl->sdl_type == IFT_USB) { //IFT_USB
    printf("%s is usb adapter\n", tmp->ifa_name);
            }
        }

        freeifaddrs(addrs);
}

如果我用 gcc 编译这段小代码，我会得到错误:

fatal error: net/if_dl.h: No such file or directory

我评论了//#include <net/if_dl.h>然后我再次编译并得到另一个错误:

fatal error: net/if_types.h: No such file or directory

然后我评论了//#include <net/if_types.h>我编译所以我得到了这个错误:

ethernetifaces.c: In function ‘main’:
ethernetifaces.c:48:13: error: dereferencing pointer to incomplete type ‘struct sockaddr_dl’
      if (sdl->sdl_type == IFT_USB) { //IFT_USB
             ^
ethernetifaces.c:48:27: error: ‘IFT_USB’ undeclared (first use in this function)
      if (sdl->sdl_type == IFT_USB) { //IFT_USB
           ^
ethernetifaces.c:48:27: note: each undeclared identifier is reported only once for each function it appears in

似乎是因为应该包含“struct sockaddr_dl”和“IFT_USB”的头文件被注释掉了。

有人知道什么是新的头文件吗？或者是否有gcc选项命令可以在编译时看到头文件？

内核版本:4.15.0-54-generic

Answer 1

我部分解决了您安装 freebsd-glue 的问题( sudo apt-get install freebsd-glue ) 并进行一些变通。

• 首先是创建文件 if_types.h 从互联网上搜索并将其插入到目录 /usr/include/freebsd/net. 中

• 第二个是注释行#include_next <net/if_dl.h>进入文件 if_dl.h ( /usr/include/freebsd/net/if_dl.h )

• 第三个是插入结构体的声明sockaddr_dl到你的代码中。

这是您的代码和一些解决方法:

#include <stdio.h>
#include <stdlib.h>

/*The following include files for the network interface. */
#include <sys/types.h>
#include <sys/socket.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <freebsd/net/if_dl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <freebsd/net/if_types.h>
/* For "toupper". */
#include <ctype.h>
/* For "strerror". */
#include <string.h>
/* For "errno". */
#include <errno.h>

/*
 * Structure of a Link-Level sockaddr:
 */
struct sockaddr_dl {
    unsigned char   sdl_len;    /* Total length of sockaddr */
    unsigned char   sdl_family; /* AF_LINK */
    unsigned short  sdl_index;  /* if != 0, system given index for interface */
    unsigned char   sdl_type;   /* interface type */
    unsigned char   sdl_nlen;   /* interface name length, no trailing 0 reqd. */
    unsigned char   sdl_alen;   /* link level address length */
    unsigned char   sdl_slen;   /* link layer selector length */
    char    sdl_data[46];   /* minimum work area, can be larger;
                   contains both if name and ll address */
};

    int main() {
            struct ifaddrs *addrs,*tmp;

            getifaddrs(&addrs);
            tmp = addrs;
            struct sockaddr_dl * sdl;

            while (tmp)
            {
                if (tmp->ifa_addr && tmp->ifa_addr->sa_family == AF_PACKET) {
                    sdl = (struct sockaddr_dl *) tmp->ifa_addr;
                    printf("%s %d - ", tmp->ifa_name, sdl->sdl_type);
                    if (sdl->sdl_type == IFT_USB) { //IFT_USB
                        printf("%s is usb adapter", tmp->ifa_name);
                    }
                    puts("");
                }

                tmp = tmp->ifa_next;
            }

            freeifaddrs(addrs);
    }

这是 if_types.h 文件:

/*
 * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1989, 1993, 1994
 *  The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *  @(#)if_types.h  8.2 (Berkeley) 4/20/94
 * $FreeBSD: src/sys/net/if_types.h,v 1.8.2.3 2001/07/03 11:01:41 ume Exp $
 */
#ifndef _NET_IF_TYPES_H_
#define _NET_IF_TYPES_H_
// #include <sys/appleapiopts.h>
/*
 * Interface types for benefit of parsing media address headers.
 * This list is derived from the SNMP list of ifTypes, currently
 * documented in RFC1573.
 * The current list of assignments is maintained at:
 *  http://www.iana.org/assignments/smi-numbers
 */
#define IFT_OTHER   0x1     /* none of the following */
#define IFT_1822    0x2     /* old-style arpanet imp */
#define IFT_HDH1822 0x3     /* HDH arpanet imp */
#define IFT_X25DDN  0x4     /* x25 to imp */
#define IFT_X25     0x5     /* PDN X25 interface (RFC877) */
#define IFT_ETHER   0x6     /* Ethernet CSMACD */
#define IFT_ISO88023    0x7     /* CMSA CD */
#define IFT_ISO88024    0x8     /* Token Bus */
#define IFT_ISO88025    0x9     /* Token Ring */
#define IFT_ISO88026    0xa     /* MAN */
#define IFT_STARLAN 0xb
#define IFT_P10     0xc     /* Proteon 10MBit ring */
#define IFT_P80     0xd     /* Proteon 80MBit ring */
#define IFT_HY      0xe     /* Hyperchannel */
#define IFT_FDDI    0xf
#define IFT_LAPB    0x10
#define IFT_SDLC    0x11
#define IFT_T1      0x12
#define IFT_CEPT    0x13        /* E1 - european T1 */
#define IFT_ISDNBASIC   0x14
#define IFT_ISDNPRIMARY 0x15
#define IFT_PTPSERIAL   0x16        /* Proprietary PTP serial */
#define IFT_PPP     0x17        /* RFC 1331 */
#define IFT_LOOP    0x18        /* loopback */
#define IFT_EON     0x19        /* ISO over IP */
#define IFT_XETHER  0x1a        /* obsolete 3MB experimental ethernet */
#define IFT_NSIP    0x1b        /* XNS over IP */
#define IFT_SLIP    0x1c        /* IP over generic TTY */
#define IFT_ULTRA   0x1d        /* Ultra Technologies */
#define IFT_DS3     0x1e        /* Generic T3 */
#define IFT_SIP     0x1f        /* SMDS */
#define IFT_FRELAY  0x20        /* Frame Relay DTE only */
#define IFT_RS232   0x21
#define IFT_PARA    0x22        /* parallel-port */
#define IFT_ARCNET  0x23
#define IFT_ARCNETPLUS  0x24
#define IFT_ATM     0x25        /* ATM cells */
#define IFT_MIOX25  0x26
#define IFT_SONET   0x27        /* SONET or SDH */
#define IFT_X25PLE  0x28
#define IFT_ISO88022LLC 0x29
#define IFT_LOCALTALK   0x2a
#define IFT_SMDSDXI 0x2b
#define IFT_FRELAYDCE   0x2c        /* Frame Relay DCE */
#define IFT_V35     0x2d
#define IFT_HSSI    0x2e
#define IFT_HIPPI   0x2f
#define IFT_MODEM   0x30        /* Generic Modem */
#define IFT_AAL5    0x31        /* AAL5 over ATM */
#define IFT_SONETPATH   0x32
#define IFT_SONETVT 0x33
#define IFT_SMDSICIP    0x34        /* SMDS InterCarrier Interface */
#define IFT_PROPVIRTUAL 0x35        /* Proprietary Virtual/internal */
#define IFT_PROPMUX 0x36        /* Proprietary Multiplexing */
/*
 * IFT_GIF, IFT_FAITH and IFT_FAITH are not based on IANA assignments.
 * Note: IFT_STF has a defined ifType: 0xd7 (215), but we use 0x39.
 */
#define IFT_GIF     0x37        /*0xf0*/
#define IFT_FAITH   0x38        /*0xf2*/
#define IFT_STF     0x39        /*0xf3*/
#define IFT_L2VLAN  0x87        /* Layer 2 Virtual LAN using 802.1Q */
#define IFT_IEEE8023ADLAG 0x88      /* IEEE802.3ad Link Aggregate */
#define IFT_IEEE1394    0x90        /* IEEE1394 High Performance SerialBus*/
#define IFT_USB     0xa0        /* USB net*/
#define IFT_BRIDGE  0xd1        /* Transparent bridge interface */
#define IFT_ENC     0xf4        /* Encapsulation */
#define IFT_PFLOG   0xf5        /* Packet filter logging */
#define IFT_PFSYNC  0xf6        /* Packet filter state syncing */
#define IFT_CARP    0xf8        /* Common Address Redundancy Protocol */
#define IFT_PKTAP   0xfe        /* Packet tap pseudo interface */
#define IFT_CELLULAR    0xff        /* Packet Data over Cellular */
#define IFT_PDP     IFT_CELLULAR    /* deprecated; use IFT_CELLULAR */
#endif

这是(修改后的)文件 if_dl.h:

//#include_next <net/if_dl.h>

#ifndef _FREEBSD_NET_IF_DL_H_
#define _FREEBSD_NET_IF_DL_H_

__BEGIN_DECLS
void    link_addr(const char *, struct sockaddr_dl *);
char    *link_ntoa(const struct sockaddr_dl *);
__END_DECLS

#endif

现在代码可以编译了，但我不确定代码是否能够识别 usb 网络适配器。