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-rw-r--r--dhcpcd/if-pref.c105
1 files changed, 105 insertions, 0 deletions
diff --git a/dhcpcd/if-pref.c b/dhcpcd/if-pref.c
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+++ b/dhcpcd/if-pref.c
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+/*
+ * dhcpcd - DHCP client daemon
+ * Copyright (c) 2006-2013 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 "dhcp.h"
+#include "if-pref.h"
+#include "net.h"
+
+/* Interface comparer for working out ordering. */
+static int
+ifcmp(const struct interface *si, const struct interface *ti)
+{
+ int sill, till;
+ const struct dhcp_state *sis, *tis;
+
+ sis = D_CSTATE(si);
+ tis = D_CSTATE(ti);
+ if (sis && !tis)
+ return -1;
+ if (!sis && tis)
+ return 1;
+ if (!sis && !tis)
+ return 0;
+ /* If one has a lease and the other not, it takes precedence. */
+ if (sis->new && !tis->new)
+ return -1;
+ if (!sis->new && tis->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 (sis->new && tis->new) {
+ sill = (sis->new->cookie == htonl(MAGIC_COOKIE));
+ till = (tis->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 if_head sorted;
+ struct interface *ifp, *ift;
+
+ if (ifaces == NULL ||
+ (ifp = TAILQ_FIRST(ifaces)) == NULL ||
+ TAILQ_NEXT(ifp, next) == NULL)
+ return;
+
+ TAILQ_INIT(&sorted);
+ TAILQ_REMOVE(ifaces, ifp, next);
+ TAILQ_INSERT_HEAD(&sorted, ifp, next);
+ while ((ifp = TAILQ_FIRST(ifaces))) {
+ TAILQ_REMOVE(ifaces, ifp, next);
+ TAILQ_FOREACH(ift, &sorted, next) {
+ if (ifcmp(ifp, ift) == -1) {
+ TAILQ_INSERT_BEFORE(ift, ifp, next);
+ break;
+ }
+ }
+ if (ift == NULL)
+ TAILQ_INSERT_TAIL(&sorted, ifp, next);
+ }
+ TAILQ_CONCAT(ifaces, &sorted, next);
+}