diff options
Diffstat (limited to 'if-pref.c')
| -rw-r--r-- | if-pref.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/if-pref.c b/if-pref.c new file mode 100644 index 0000000..83b1b0f --- /dev/null +++ b/if-pref.c @@ -0,0 +1,108 @@ +/* + * dhcpcd - DHCP client daemon + * Copyright (c) 2006-2010 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; +} |