Re: libpcap on linux issue

[Guy Harris <guy () netapp com>]

On Wed, Feb 12, 2003 at 02:39:35PM +1100, Darren Reed wrote:
> I'm using libpcap-2002.12.08 on a RedHat 8.0 box and have come across an
> issue that I think is quite serious.
>
> In fad-getad.c

So presumably this means that RH 8.0 has "getifaddrs()".

> One solution to this is changing the #define from being
> "sizeof(struct sockaddr_storage)" to be something else - like this:
> #define SA_LEN(x)     sizeof(*x)

...which works only if, on platforms with "struct sockaddr_storage" and
"getifaddrs()", and no "SA_LEN()" macro, no address is bigger than the
type of the addresses in the structure returned by "getifaddrs()".  That
either means that

        1) IPv6 isn't supported;

        2) "struct sockaddr" is big enough, in those systems, for an
           IPv6 address;

        3) "struct ifaddrs", on that platform, doesn't have "struct
           sockaddr" pointers in it.

For each of the platforms with "struct sockaddr_storage" and
"getifaddrs()", and no "SA_LEN()", which of those is the case?  (Note
that 1) is a bit behind the times, 2) is a bit surprising, and 3) is a
bit incompatible.  That makes 2) the most *desirable* and *sensible* of
those options, but nobody ever went broke assuming developers would
always choose the most desirable and sensible option....)

Or is there some *other* way, on RH 8.0, of inquiring how big the
address pointed to by a pointer in a "struct ifaddrs" is?
-
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