1 /* $OpenBSD: carp.c,v 1.11 2022/08/17 15:15:25 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 *
carp_group_find(char * group)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
carp_demote_init(char * group,int force)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
carp_demote_shutdown(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
carp_demote_get(char * group)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 memset(&ifgr, 0, 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
carp_demote_set(char * group,int demote)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
carp_demote_ioctl(char * group,int demote)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 memset(&ifgr, 0, 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