Sort interfaces according to preference and pass this to dhcpcd-run-hooks so we can prefer configs.

1 files changed, 99 insertions, 0 deletions

diff --git a/if-pref.c b/if-pref.c
new file mode 100644
index 00000000..c6c008e7
--- /dev/null
+++ b/if-pref.c
@@ -0,0 +1,99 @@
+/* 
+ * dhcpcd - DHCP client daemon
+ * Copyright 2006-2008 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 "config.h"
+#include "dhcpcd.h"
+#include "if-pref.h"
+
+/* Interface comparer for working out ordering. */
+static int
+ifcmp(struct interface *si, struct interface *ti)
+{
+	int sill, till;
+
+	/* 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) {
+		sill = IN_LINKLOCAL(htonl(si->state->new->yiaddr));
+		till = IN_LINKLOCAL(htonl(ti->state->new->yiaddr));
+		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;
+}