1 /* $OpenBSD: carp.c,v 1.10 2019/08/08 20:06:29 claudio Exp $ */ 2 3 /* 4 * Copyright (c) 2006 Henning Brauer <henning@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 #include <sys/socket.h> 21 #include <sys/ioctl.h> 22 #include <net/if.h> 23 24 #include <errno.h> 25 #include <string.h> 26 #include <stdlib.h> 27 #include <unistd.h> 28 29 #include "bgpd.h" 30 #include "session.h" 31 #include "log.h" 32 33 struct carpgroup { 34 TAILQ_ENTRY(carpgroup) entry; 35 char *group; 36 int do_demote; 37 int changed_by; 38 }; 39 40 TAILQ_HEAD(carpgroups, carpgroup) carpgroups = 41 TAILQ_HEAD_INITIALIZER(carpgroups); 42 43 struct carpgroup *carp_group_find(char *group); 44 int carp_demote_ioctl(char *, int); 45 46 struct carpgroup * 47 carp_group_find(char *group) 48 { 49 struct carpgroup *c; 50 51 TAILQ_FOREACH(c, &carpgroups, entry) 52 if (!strcmp(c->group, group)) 53 return (c); 54 55 return (NULL); 56 } 57 58 int 59 carp_demote_init(char *group, int force) 60 { 61 struct carpgroup *c; 62 int level; 63 64 if ((c = carp_group_find(group)) == NULL) { 65 if ((c = calloc(1, sizeof(struct carpgroup))) == NULL) { 66 log_warn("carp_demote_init calloc"); 67 return (-1); 68 } 69 if ((c->group = strdup(group)) == NULL) { 70 log_warn("carp_demote_init strdup"); 71 free(c); 72 return (-1); 73 } 74 75 /* only demote if this group already is demoted */ 76 if ((level = carp_demote_get(group)) == -1) { 77 free(c->group); 78 free(c); 79 return (-1); 80 } 81 if (level > 0 || force) 82 c->do_demote = 1; 83 84 TAILQ_INSERT_TAIL(&carpgroups, c, entry); 85 } 86 87 return (0); 88 } 89 90 void 91 carp_demote_shutdown(void) 92 { 93 struct carpgroup *c; 94 95 while ((c = TAILQ_FIRST(&carpgroups)) != NULL) { 96 TAILQ_REMOVE(&carpgroups, c, entry); 97 if (c->do_demote && c->changed_by > 0) 98 carp_demote_ioctl(c->group, -c->changed_by); 99 100 free(c->group); 101 free(c); 102 } 103 } 104 105 int 106 carp_demote_get(char *group) 107 { 108 int s; 109 struct ifgroupreq ifgr; 110 111 if ((s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0)) == -1) { 112 log_warn("carp_demote_get: socket"); 113 return (-1); 114 } 115 116 bzero(&ifgr, sizeof(ifgr)); 117 strlcpy(ifgr.ifgr_name, group, sizeof(ifgr.ifgr_name)); 118 119 if (ioctl(s, SIOCGIFGATTR, (caddr_t)&ifgr) == -1) { 120 if (errno == ENOENT) 121 log_warnx("group \"%s\" does not exist", group); 122 else 123 log_warn("carp_demote_get: ioctl"); 124 close(s); 125 return (-1); 126 } 127 128 close(s); 129 return ((int)ifgr.ifgr_attrib.ifg_carp_demoted); 130 } 131 132 int 133 carp_demote_set(char *group, int demote) 134 { 135 struct carpgroup *c; 136 137 if ((c = carp_group_find(group)) == NULL) { 138 log_warnx("carp_group_find for %s returned NULL?!", group); 139 return (-1); 140 } 141 142 if (c->changed_by + demote < 0) { 143 log_warnx("carp_demote_set: changed_by + demote < 0"); 144 return (-1); 145 } 146 147 if (c->do_demote && carp_demote_ioctl(group, demote) == -1) 148 return (-1); 149 150 c->changed_by += demote; 151 152 /* enable demotion when we return to 0, i. e. all sessions up */ 153 if (demote < 0 && c->changed_by == 0) 154 c->do_demote = 1; 155 156 return (0); 157 } 158 159 int 160 carp_demote_ioctl(char *group, int demote) 161 { 162 int s, res; 163 struct ifgroupreq ifgr; 164 165 if ((s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0)) == -1) { 166 log_warn("%s: socket", __func__); 167 return (-1); 168 } 169 170 bzero(&ifgr, sizeof(ifgr)); 171 strlcpy(ifgr.ifgr_name, group, sizeof(ifgr.ifgr_name)); 172 ifgr.ifgr_attrib.ifg_carp_demoted = demote; 173 174 if ((res = ioctl(s, SIOCSIFGATTR, (caddr_t)&ifgr)) == -1) 175 log_warn("unable to %s the demote state " 176 "of group '%s'", (demote > 0) ? "increment" : "decrement", 177 group); 178 else 179 log_info("%s the demote state of group '%s'", 180 (demote > 0) ? "incremented" : "decremented", group); 181 182 close(s); 183 return (res); 184 } 185