xcode 在 Objective-C 中获取路由器 mac（没有对 ARP 的系统调用）
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Get router mac (without system call for ARP) in Objective-C
提问by Andrew J. Freyer
Ok - I am writing a daemon in Objective C that checks the connected router mac address every 5 seconds.
好的 - 我正在用 Objective C 编写一个守护进程，它每 5 秒检查一次连接的路由器 mac 地址。
I am completely new to objective C, and I am looking for a better way to do what I'm already doing.
我对目标 C 完全陌生，我正在寻找一种更好的方法来做我已经在做的事情。
I'm currently calling "arp -a" and parsing the results via "Task":
我目前正在调用“arp -a”并通过“Task”解析结果：
NSTask *task;
task = [[NSTask alloc] init];
[task setLaunchPath: @"/usr/sbin/arp"];
NSArray *arguments;
arguments = [NSArray arrayWithObjects: @"-a", nil];
[task setArguments: arguments];
NSPipe *pipe;
pipe = [NSPipe pipe];
[task setStandardOutput: pipe];
NSFileHandle *file;
file = [pipe fileHandleForReading];
[task launch];
NSData *data;
data = [file readDataToEndOfFile];
I'm afraid that this isn't very efficient.
恐怕这不是很有效。
Any suggestions? I am running this codeblock once every 5 seconds.
有什么建议？我每 5 秒运行一次此代码块。
采纳答案by Matt B.
Apple's implementation of arpis open source. Take a look at the filefor an idea of its implementation... it's not terribly convoluted. It is pure ANSI C, though.
Apple 的实现arp是开源的。查看该文件以了解其实现的想法......它并不是非常复杂。不过，它是纯 ANSI C。
You should be able to simply copy-paste the majority of the functionality... and instead of printing the results, just store the raw address.
您应该能够简单地复制粘贴大部分功能......而不是打印结果，只需存储原始地址。
Edit:Here's a stripped down version of the source that just runs the equivalent of arp -a. This should compile without any special directives.
编辑：这是源代码的精简版本，它只运行相当于arp -a. 这应该在没有任何特殊指令的情况下编译。
/*
* Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
*
* @APPLE_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. 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_LICENSE_HEADER_END@
*/
#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#include <err.h>
#include <errno.h>
#include <netdb.h>
#include <nlist.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static int nflag;
void
ether_print(cp)
u_char *cp;
{
printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]);
}
/*
* Dump the entire arp table
*/
int
dump(addr)
u_long addr;
{
int mib[6];
size_t needed;
char *host, *lim, *buf, *next;
struct rt_msghdr *rtm;
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
extern int h_errno;
struct hostent *hp;
int found_entry = 0;
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = AF_INET;
mib[4] = NET_RT_FLAGS;
mib[5] = RTF_LLINFO;
if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
err(1, "route-sysctl-estimate");
if ((buf = malloc(needed)) == NULL)
err(1, "malloc");
if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
err(1, "actual retrieval of routing table");
lim = buf + needed;
for (next = buf; next < lim; next += rtm->rtm_msglen) {
rtm = (struct rt_msghdr *)next;
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin + 1);
if (addr) {
if (addr != sin->sin_addr.s_addr)
continue;
found_entry = 1;
}
if (nflag == 0)
hp = gethostbyaddr((caddr_t)&(sin->sin_addr),
sizeof sin->sin_addr, AF_INET);
else
hp = 0;
if (hp)
host = hp->h_name;
else {
host = "?";
if (h_errno == TRY_AGAIN)
nflag = 1;
}
printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr));
if (sdl->sdl_alen)
ether_print((u_char *)LLADDR(sdl));
else
printf("(incomplete)");
if (rtm->rtm_rmx.rmx_expire == 0)
printf(" permanent");
if (sin->sin_other & SIN_PROXY)
printf(" published (proxy only)");
if (rtm->rtm_addrs & RTA_NETMASK) {
sin = (struct sockaddr_inarp *)
(sdl->sdl_len + (char *)sdl);
if (sin->sin_addr.s_addr == 0xffffffff)
printf(" published");
if (sin->sin_len != 8)
printf("(weird)");
}
printf("\n");
}
return (found_entry);
}
int main (int argc, char const *argv[])
{
dump(0);
return 0;
}
