1 /* $OpenBSD: control.c,v 1.9 2021/03/20 16:46:03 kn Exp $ */ 2 3 /* 4 * Copyright (c) 2003, 2004 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 #ifndef SMALL 19 #include <sys/types.h> 20 #include <sys/queue.h> 21 #include <sys/stat.h> 22 #include <sys/socket.h> 23 #include <sys/uio.h> 24 #include <sys/un.h> 25 26 #include <net/if.h> 27 #include <netinet/in.h> 28 #include <netinet/if_ether.h> 29 30 #include <errno.h> 31 #include <event.h> 32 #include <imsg.h> 33 #include <stdlib.h> 34 #include <string.h> 35 #include <unistd.h> 36 37 #include "log.h" 38 #include "slaacd.h" 39 #include "control.h" 40 #include "frontend.h" 41 42 #define CONTROL_BACKLOG 5 43 44 struct { 45 struct event ev; 46 struct event evt; 47 int fd; 48 } control_state = {.fd = -1}; 49 50 struct ctl_conn { 51 TAILQ_ENTRY(ctl_conn) entry; 52 struct imsgev iev; 53 }; 54 55 struct ctl_conn *control_connbyfd(int); 56 struct ctl_conn *control_connbypid(pid_t); 57 void control_close(int); 58 59 TAILQ_HEAD(ctl_conns, ctl_conn) ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns); 60 61 int 62 control_init(char *path) 63 { 64 struct sockaddr_un sun; 65 int fd; 66 mode_t old_umask; 67 68 if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 69 0)) == -1) { 70 log_warn("%s: socket", __func__); 71 return (-1); 72 } 73 74 memset(&sun, 0, sizeof(sun)); 75 sun.sun_family = AF_UNIX; 76 strlcpy(sun.sun_path, path, sizeof(sun.sun_path)); 77 78 if (unlink(path) == -1) 79 if (errno != ENOENT) { 80 log_warn("%s: unlink %s", __func__, path); 81 close(fd); 82 return (-1); 83 } 84 85 old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH); 86 if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) { 87 log_warn("%s: bind: %s", __func__, path); 88 close(fd); 89 umask(old_umask); 90 return (-1); 91 } 92 umask(old_umask); 93 94 if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) { 95 log_warn("%s: chmod", __func__); 96 close(fd); 97 (void)unlink(path); 98 return (-1); 99 } 100 101 return (fd); 102 } 103 104 int 105 control_listen(int fd) 106 { 107 if (control_state.fd != -1) 108 fatalx("%s: received unexpected controlsock", __func__); 109 110 control_state.fd = fd; 111 if (listen(control_state.fd, CONTROL_BACKLOG) == -1) { 112 log_warn("%s: listen", __func__); 113 return (-1); 114 } 115 116 event_set(&control_state.ev, control_state.fd, EV_READ, 117 control_accept, NULL); 118 event_add(&control_state.ev, NULL); 119 evtimer_set(&control_state.evt, control_accept, NULL); 120 121 return (0); 122 } 123 124 void 125 control_accept(int listenfd, short event, void *bula) 126 { 127 int connfd; 128 socklen_t len; 129 struct sockaddr_un sun; 130 struct ctl_conn *c; 131 132 event_add(&control_state.ev, NULL); 133 if ((event & EV_TIMEOUT)) 134 return; 135 136 len = sizeof(sun); 137 if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len, 138 SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) { 139 /* 140 * Pause accept if we are out of file descriptors, or 141 * libevent will haunt us here too. 142 */ 143 if (errno == ENFILE || errno == EMFILE) { 144 struct timeval evtpause = { 1, 0 }; 145 146 event_del(&control_state.ev); 147 evtimer_add(&control_state.evt, &evtpause); 148 } else if (errno != EWOULDBLOCK && errno != EINTR && 149 errno != ECONNABORTED) 150 log_warn("%s: accept4", __func__); 151 return; 152 } 153 154 if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) { 155 log_warn("%s: calloc", __func__); 156 close(connfd); 157 return; 158 } 159 160 imsg_init(&c->iev.ibuf, connfd); 161 c->iev.handler = control_dispatch_imsg; 162 c->iev.events = EV_READ; 163 event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events, 164 c->iev.handler, &c->iev); 165 event_add(&c->iev.ev, NULL); 166 167 TAILQ_INSERT_TAIL(&ctl_conns, c, entry); 168 } 169 170 struct ctl_conn * 171 control_connbyfd(int fd) 172 { 173 struct ctl_conn *c; 174 175 TAILQ_FOREACH(c, &ctl_conns, entry) { 176 if (c->iev.ibuf.fd == fd) 177 break; 178 } 179 180 return (c); 181 } 182 183 struct ctl_conn * 184 control_connbypid(pid_t pid) 185 { 186 struct ctl_conn *c; 187 188 TAILQ_FOREACH(c, &ctl_conns, entry) { 189 if (c->iev.ibuf.pid == pid) 190 break; 191 } 192 193 return (c); 194 } 195 196 void 197 control_close(int fd) 198 { 199 struct ctl_conn *c; 200 201 if ((c = control_connbyfd(fd)) == NULL) { 202 log_warnx("%s: fd %d: not found", __func__, fd); 203 return; 204 } 205 206 msgbuf_clear(&c->iev.ibuf.w); 207 TAILQ_REMOVE(&ctl_conns, c, entry); 208 209 event_del(&c->iev.ev); 210 close(c->iev.ibuf.fd); 211 212 /* Some file descriptors are available again. */ 213 if (evtimer_pending(&control_state.evt, NULL)) { 214 evtimer_del(&control_state.evt); 215 event_add(&control_state.ev, NULL); 216 } 217 218 free(c); 219 } 220 221 void 222 control_dispatch_imsg(int fd, short event, void *bula) 223 { 224 struct ctl_conn *c; 225 struct imsg imsg; 226 ssize_t n; 227 int verbose; 228 229 if ((c = control_connbyfd(fd)) == NULL) { 230 log_warnx("%s: fd %d: not found", __func__, fd); 231 return; 232 } 233 234 if (event & EV_READ) { 235 if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) || 236 n == 0) { 237 control_close(fd); 238 return; 239 } 240 } 241 if (event & EV_WRITE) { 242 if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) { 243 control_close(fd); 244 return; 245 } 246 } 247 248 for (;;) { 249 if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) { 250 control_close(fd); 251 return; 252 } 253 if (n == 0) 254 break; 255 256 switch (imsg.hdr.type) { 257 case IMSG_CTL_LOG_VERBOSE: 258 if (IMSG_DATA_SIZE(imsg) != sizeof(verbose)) 259 break; 260 261 /* Forward to all other processes. */ 262 frontend_imsg_compose_main(imsg.hdr.type, imsg.hdr.pid, 263 imsg.data, IMSG_DATA_SIZE(imsg)); 264 frontend_imsg_compose_engine(imsg.hdr.type, 0, 265 imsg.hdr.pid, imsg.data, IMSG_DATA_SIZE(imsg)); 266 267 memcpy(&verbose, imsg.data, sizeof(verbose)); 268 log_setverbose(verbose); 269 break; 270 case IMSG_CTL_SHOW_INTERFACE_INFO: 271 if (IMSG_DATA_SIZE(imsg) != sizeof(uint32_t)) 272 break; 273 c->iev.ibuf.pid = imsg.hdr.pid; 274 frontend_imsg_compose_engine(imsg.hdr.type, 0, 275 imsg.hdr.pid, imsg.data, IMSG_DATA_SIZE(imsg)); 276 break; 277 case IMSG_CTL_SEND_SOLICITATION: 278 if (IMSG_DATA_SIZE(imsg) != sizeof(uint32_t)) 279 break; 280 c->iev.ibuf.pid = imsg.hdr.pid; 281 frontend_imsg_compose_engine(imsg.hdr.type, 0, 282 imsg.hdr.pid, imsg.data, IMSG_DATA_SIZE(imsg)); 283 break; 284 default: 285 log_debug("%s: error handling imsg %d", __func__, 286 imsg.hdr.type); 287 break; 288 } 289 imsg_free(&imsg); 290 } 291 292 imsg_event_add(&c->iev); 293 } 294 295 int 296 control_imsg_relay(struct imsg *imsg) 297 { 298 struct ctl_conn *c; 299 300 if ((c = control_connbypid(imsg->hdr.pid)) == NULL) 301 return (0); 302 303 return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid, 304 -1, imsg->data, IMSG_DATA_SIZE(*imsg))); 305 } 306 #endif /* SMALL */ 307