1 /* $OpenBSD: carp.c,v 1.12 2016/08/18 00:45:52 jsg 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/queue.h>
22 #include <sys/ioctl.h>
23
24 #include <net/if.h>
25
26 #include <errno.h>
27 #include <string.h>
28 #include <stdlib.h>
29 #include <unistd.h>
30
31 #include "relayd.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("%s: calloc", __func__);
67 return (-1);
68 }
69 if ((c->group = strdup(group)) == NULL) {
70 log_warn("%s: strdup", __func__);
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, 0)) == -1) {
112 log_warn("%s: socket", __func__);
113 return (-1);
114 }
115
116 bzero(&ifgr, sizeof(ifgr));
117 if (strlcpy(ifgr.ifgr_name, group, sizeof(ifgr.ifgr_name)) >=
118 sizeof(ifgr.ifgr_name)) {
119 log_warn("%s: invalid group", __func__);
120 close(s);
121 return (-1);
122 }
123
124 if (ioctl(s, SIOCGIFGATTR, (caddr_t)&ifgr) == -1) {
125 if (errno == ENOENT)
126 log_warnx("%s: group \"%s\" does not exist",
127 __func__, group);
128 else
129 log_warn("%s: ioctl", __func__);
130 close(s);
131 return (-1);
132 }
133
134 close(s);
135 return ((int)ifgr.ifgr_attrib.ifg_carp_demoted);
136 }
137
138 int
carp_demote_set(char * group,int demote)139 carp_demote_set(char *group, int demote)
140 {
141 struct carpgroup *c;
142
143 if ((c = carp_group_find(group)) == NULL) {
144 log_warnx("%s: carp group %s not found", __func__, group);
145 return (-1);
146 }
147
148 if (c->changed_by + demote < 0) {
149 log_warnx("%s: changed_by + demote < 0", __func__);
150 return (-1);
151 }
152
153 if (c->do_demote && carp_demote_ioctl(group, demote) == -1)
154 return (-1);
155
156 c->changed_by += demote;
157
158 /* enable demotion when we return to 0, i. e. all sessions up */
159 if (demote < 0 && c->changed_by == 0)
160 c->do_demote = 1;
161
162 return (0);
163 }
164
165 int
carp_demote_reset(char * group,int value)166 carp_demote_reset(char *group, int value)
167 {
168 int level;
169 int demote = 0;
170
171 if (value < 0) {
172 log_warnx("%s: value < 0", __func__);
173 return (-1);
174 }
175
176 if ((level = carp_demote_get(group)) == -1)
177 return (-1);
178 if (level == value)
179 return (0);
180
181 demote -= level;
182 demote += value;
183
184 if (carp_demote_ioctl(group, demote) == -1)
185 return (-1);
186
187 return (0);
188 }
189
190 int
carp_demote_ioctl(char * group,int demote)191 carp_demote_ioctl(char *group, int demote)
192 {
193 int s, res;
194 struct ifgroupreq ifgr;
195
196 if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
197 log_warn("%s: socket", __func__);
198 return (-1);
199 }
200
201 bzero(&ifgr, sizeof(ifgr));
202 if (strlcpy(ifgr.ifgr_name, group, sizeof(ifgr.ifgr_name)) >=
203 sizeof(ifgr.ifgr_name)) {
204 log_warn("%s: invalid group", __func__);
205 close(s);
206 return (-1);
207 }
208 ifgr.ifgr_attrib.ifg_carp_demoted = demote;
209
210 if ((res = ioctl(s, SIOCSIFGATTR, (caddr_t)&ifgr)) == -1)
211 log_warn("%s: unable to %s the demote state "
212 "of group '%s'", __func__,
213 (demote > 0) ? "increment" : "decrement", group);
214 else
215 log_info("%s the demote state of group '%s'",
216 (demote > 0) ? "incremented" : "decremented", group);
217
218 close(s);
219 return (res);
220 }
221