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/*
* dhcpcd - DHCP client daemon
* Copyright (c) 2006-2012 Roy Marples <roy@marples.name>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/types.h>
#include "config.h"
#include "dhcpcd.h"
#include "if-pref.h"
#include "net.h"
/* Interface comparer for working out ordering. */
static int
ifcmp(struct interface *si, struct interface *ti)
{
int sill, till;
if (si->state && !ti->state)
return -1;
if (!si->state && ti->state)
return 1;
if (!si->state && !ti->state)
return 0;
/* If one has a lease and the other not, it takes precedence. */
if (si->state->new && !ti->state->new)
return -1;
if (!si->state->new && ti->state->new)
return 1;
/* If we are either, they neither have a lease, or they both have.
* We need to check for IPv4LL and make it non-preferred. */
if (si->state->new && ti->state->new) {
sill = (si->state->new->cookie == htonl(MAGIC_COOKIE));
till = (ti->state->new->cookie == htonl(MAGIC_COOKIE));
if (!sill && till)
return 1;
if (sill && !till)
return -1;
}
/* Then carrier status. */
if (si->carrier > ti->carrier)
return -1;
if (si->carrier < ti->carrier)
return 1;
/* Finally, metric */
if (si->metric < ti->metric)
return -1;
if (si->metric > ti->metric)
return 1;
return 0;
}
/* Sort the interfaces into a preferred order - best first, worst last. */
void
sort_interfaces(void)
{
struct interface *sorted, *ifp, *ifn, *ift;
if (!ifaces || !ifaces->next)
return;
sorted = ifaces;
ifaces = ifaces->next;
sorted->next = NULL;
for (ifp = ifaces; ifp && (ifn = ifp->next, 1); ifp = ifn) {
/* Are we the new head? */
if (ifcmp(ifp, sorted) == -1) {
ifp->next = sorted;
sorted = ifp;
continue;
}
/* Do we fit in the middle? */
for (ift = sorted; ift->next; ift = ift->next) {
if (ifcmp(ifp, ift->next) == -1) {
ifp->next = ift->next;
ift->next = ifp;
break;
}
}
/* We must be at the end */
if (!ift->next) {
ift->next = ifp;
ifp->next = NULL;
}
}
ifaces = sorted;
}
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