Re: if_nameindex/getifaddrs and dhcpcd issue

[Szabolcs Nagy <nsz@port70.net>]

* Justin Cormack <justin@specialbusservice.com> [2014-04-08 11:07:47 +0100]:
> I am not sure that it is appropriate that a netlink implementation,
> which is the only way to do the enumeration correctly in the potential
> absense of /proc, should go into Musl. I would be more inclined to

one could just try all the numbers.. this "works" even at boot time :)
(and there is /sys/class/net/*/ifindex but that does not help libc)


#include <net/if.h>
#include <stdlib.h>
#include <errno.h>
#define N 256
struct if_nameindex *if_nameindex()
{
	struct if_nameindex *p = malloc(N*sizeof*p + N*IF_NAMESIZE);
	if (!p) errno = ENOBUFS;
	else {
		char (*name)[IF_NAMESIZE] = (void*)(p+N);
		int i,j;
		for (i=1,j=0; i<N; i++)
			if (if_indextoname(i, name[j])) {
				p[j].if_name = name[j];
				p[j].if_index = i;
				j++;
			}
		p[j].if_name = 0;
		p[j].if_index = 0;
	}
	return p;
}

> However I can see no reason why dhcp on a specified interface needs to
> enumerate interfaces at all, and it only needs to read ipv4 addresses,
> unless it is implementing dhcp6 too, maybe it does now. Again dhcp6
> needs netlink, the Musl ipv6 parts for getifaddrs already use /proc
> which is definitely unreliable for early boot config in a distro in my
> view.

if ipv6 things require netlink anyway then probably musl does not have
much choice..