[Iftop-users] (patch) Mac addresses on {Free,Open}BSD (was: Re: working in 10baseT/UTP)

[Paul Warren]

Hi Nicolas,

Thanks for this - I've now applied this to the version in CVS.

Paul

On Tue, May 03, 2005 at 12:17:08PM +0200, Nicolas Bernard wrote:
> Paul Warren(pdw@ex-parrot.com)@2005.05.02 10:40:53 +0100 wrote:
> > we need to figure out how to get the hardware address on FreeBSD,
> 
> Hi,
> 
> Here is a patch which uses sysctl to get the hardware address. I tried
> it on FreeBSD 5.3 and OpenBSD 3.5. Note that I don't know how this code
> work on an non-ethernet interface (tried on some pseudo-interface and
> get an all-0 address, but...).
> 
> I left the code in the get_addrs_ioctl fct despite the fact it uses
> sysctl because it was simpler.
> 
> Oh yes, I used gotos, I found them more readable in this case than
> deeply imbricated ifs.
> 
> Best Regards,
> Nicolas

> diff -u -r iftop-0.17pre1/addrs_ioctl.c iftop-0.17pre1-bsdmac/addrs_ioctl.c
> --- iftop-0.17pre1/addrs_ioctl.c	Tue Jul 27 10:44:13 2004
> +++ iftop-0.17pre1-bsdmac/addrs_ioctl.c	Tue May  3 11:46:49 2005
> @@ -18,6 +18,12 @@
>  #include <net/if.h>
>  #include <netinet/in.h>
>  
> +#if defined __FreeBSD__ || defined __OpenBSD__
> +#include <sys/param.h>
> +#include <sys/sysctl.h>
> +#include <net/if_dl.h>
> +#endif
> +
>  #include "iftop.h"
>  
>  /*
> @@ -65,7 +71,41 @@
>      got_hw_addr = 1;
>    }
>  #else
> +#if defined __FreeBSD__ || defined __OpenBSD__
> +  {
> +    int sysctlparam[6] = {CTL_NET, PF_ROUTE, 0, 0, NET_RT_IFLIST, 0};
> +    int needed = 0;
> +    char *buf = NULL;
> +    struct if_msghdr *msghdr = NULL;
> +    sysctlparam[5] = if_nametoindex(interface);
> +    if (sysctlparam[5] == 0) {
> +      fprintf(stderr, "Error getting hardware address for interface: %s\n", interface);
> +      goto ENDHWADDR;
> +    }
> +    if (sysctl(sysctlparam, 6, NULL, &needed, NULL, 0) < 0) {
> +      fprintf(stderr, "Error getting hardware address for interface: %s\n", interface);
> +      goto ENDHWADDR;
> +    }
> +    if ((buf = malloc(needed)) == NULL) {
> +      fprintf(stderr, "Error getting hardware address for interface: %s\n", interface);
> +      goto ENDHWADDR;
> +    }
> +    if (sysctl(sysctlparam, 6, buf, &needed, NULL, 0) < 0) {
> +      fprintf(stderr, "Error getting hardware address for interface: %s\n", interface);
> +      free(buf);
> +      goto ENDHWADDR;
> +    }
> +    msghdr = (struct if_msghdr *) buf;
> +    memcpy(if_hw_addr, LLADDR((struct sockaddr_dl *)(buf + sizeof(struct if_msghdr) - sizeof(struct if_data) + sizeof(struct if_data))), 6);
> +    free(buf);
> +    got_hw_addr = 1;
> +
> +  ENDHWADDR:
> +    1; /* compiler whines if there is a label at the end of a block...*/
> +  }
> +#else
>    fprintf(stderr, "Cannot obtain hardware address on this platform\n");
> +#endif
>  #endif
>    
>    /* Get the IP address of the interface */