1 /* 2 * dhcpcd - DHCP client daemon 3 * Copyright (c) 2006-2010 Roy Marples <roy (at) marples.name> 4 * All rights reserved 5 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/types.h> 29 30 #include "config.h" 31 #include "dhcpcd.h" 32 #include "if-pref.h" 33 #include "net.h" 34 35 /* Interface comparer for working out ordering. */ 36 static int 37 ifcmp(struct interface *si, struct interface *ti) 38 { 39 int sill, till; 40 41 if (si->state && !ti->state) 42 return -1; 43 if (!si->state && ti->state) 44 return 1; 45 if (!si->state && !ti->state) 46 return 0; 47 /* If one has a lease and the other not, it takes precedence. */ 48 if (si->state->new && !ti->state->new) 49 return -1; 50 if (!si->state->new && ti->state->new) 51 return 1; 52 /* If we are either, they neither have a lease, or they both have. 53 * We need to check for IPv4LL and make it non-preferred. */ 54 if (si->state->new && ti->state->new) { 55 sill = (si->state->new->cookie == htonl(MAGIC_COOKIE)); 56 till = (ti->state->new->cookie == htonl(MAGIC_COOKIE)); 57 if (!sill && till) 58 return -1; 59 if (sill && !till) 60 return 1; 61 } 62 /* Then carrier status. */ 63 if (si->carrier > ti->carrier) 64 return -1; 65 if (si->carrier < ti->carrier) 66 return 1; 67 /* Finally, metric */ 68 if (si->metric < ti->metric) 69 return -1; 70 if (si->metric > ti->metric) 71 return 1; 72 return 0; 73 } 74 75 /* Sort the interfaces into a preferred order - best first, worst last. */ 76 void 77 sort_interfaces(void) 78 { 79 struct interface *sorted, *ifp, *ifn, *ift; 80 81 if (!ifaces || !ifaces->next) 82 return; 83 sorted = ifaces; 84 ifaces = ifaces->next; 85 sorted->next = NULL; 86 for (ifp = ifaces; ifp && (ifn = ifp->next, 1); ifp = ifn) { 87 /* Are we the new head? */ 88 if (ifcmp(ifp, sorted) == -1) { 89 ifp->next = sorted; 90 sorted = ifp; 91 continue; 92 } 93 /* Do we fit in the middle? */ 94 for (ift = sorted; ift->next; ift = ift->next) { 95 if (ifcmp(ifp, ift->next) == -1) { 96 ifp->next = ift->next; 97 ift->next = ifp; 98 break; 99 } 100 } 101 /* We must be at the end */ 102 if (!ift->next) { 103 ift->next = ifp; 104 ifp->next = NULL; 105 } 106 } 107 ifaces = sorted; 108 } 109
