1 /***
2 This file is part of avahi.
3
4 avahi is free software; you can redistribute it and/or modify it
5 under the terms of the GNU Lesser General Public License as
6 published by the Free Software Foundation; either version 2.1 of the
7 License, or (at your option) any later version.
8
9 avahi is distributed in the hope that it will be useful, but WITHOUT
10 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
12 Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with avahi; if not, write to the Free Software
16 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
17 USA.
18 ***/
19
20 #ifdef HAVE_CONFIG_H
21 #include <config.h>
22 #endif
23
24 #include <sys/param.h>
25 #include <sys/types.h>
26 #include <sys/stat.h>
27 #include <sys/ioctl.h>
28 #ifdef HAVE_SYS_FILIO_H
29 #include <sys/filio.h>
30 #endif
31 #include <sys/socket.h>
32 #include <sys/wait.h>
33 #ifdef __FreeBSD__
34 #include <sys/sysctl.h>
35 #endif
36
37 #ifdef __linux__
38 #include <netpacket/packet.h>
39 #endif
40 #include <net/ethernet.h>
41 #include <net/if.h>
42 #ifdef __FreeBSD__
43 #include <net/if_dl.h>
44 #include <net/route.h>
45 #endif
46 #include <arpa/inet.h>
47
48 #include <assert.h>
49 #include <errno.h>
50 #include <inttypes.h>
51 #include <fcntl.h>
52 #include <stdlib.h>
53 #include <stdio.h>
54 #include <signal.h>
55 #include <string.h>
56 #include <time.h>
57 #include <getopt.h>
58
59 #include <grp.h>
60 #include <poll.h>
61 #include <pwd.h>
62 #include <unistd.h>
63
64 #ifndef __linux__
65 #include <pcap.h>
66 #endif
67
68 #include <avahi-common/malloc.h>
69 #include <avahi-common/timeval.h>
70 #include <avahi-daemon/setproctitle.h>
71
72 #include <libdaemon/dfork.h>
73 #include <libdaemon/dsignal.h>
74 #include <libdaemon/dlog.h>
75 #include <libdaemon/dpid.h>
76 #include <libdaemon/dexec.h>
77
78 #include "main.h"
79 #include "iface.h"
80
81 /* An implementation of RFC 3927 */
82
83 /* Constants from the RFC */
84 #define PROBE_WAIT 1
85 #define PROBE_NUM 3
86 #define PROBE_MIN 1
87 #define PROBE_MAX 2
88 #define ANNOUNCE_WAIT 2
89 #define ANNOUNCE_NUM 2
90 #define ANNOUNCE_INTERVAL 2
91 #define MAX_CONFLICTS 10
92 #define RATE_LIMIT_INTERVAL 60
93 #define DEFEND_INTERVAL 10
94
95 #define IPV4LL_NETWORK 0xA9FE0000L
96 #define IPV4LL_NETMASK 0xFFFF0000L
97 #define IPV4LL_HOSTMASK 0x0000FFFFL
98 #define IPV4LL_BROADCAST 0xA9FEFFFFL
99
100 #define ETHER_ADDRLEN 6
101 #define ETHER_HDR_SIZE (2+2*ETHER_ADDRLEN)
102 #define ARP_PACKET_SIZE (8+4+4+2*ETHER_ADDRLEN)
103
104 typedef enum ArpOperation {
105 ARP_REQUEST = 1,
106 ARP_RESPONSE = 2
107 } ArpOperation;
108
109 typedef struct ArpPacketInfo {
110 ArpOperation operation;
111
112 uint32_t sender_ip_address, target_ip_address;
113 uint8_t sender_hw_address[ETHER_ADDRLEN], target_hw_address[ETHER_ADDRLEN];
114 } ArpPacketInfo;
115
116 typedef struct ArpPacket {
117 uint8_t *ether_header;
118 uint8_t *ether_payload;
119 } ArpPacket;
120
121 static State state = STATE_START;
122 static int n_iteration = 0;
123 static int n_conflict = 0;
124
125 static char *interface_name = NULL;
126 static char *pid_file_name = NULL;
127 static uint32_t start_address = 0;
128 static char *argv0 = NULL;
129 static int daemonize = 0;
130 static int wait_for_address = 0;
131 static int use_syslog = 0;
132 static int debug = 0;
133 static int modify_proc_title = 1;
134 static int force_bind = 0;
135 #ifdef HAVE_CHROOT
136 static int no_chroot = 0;
137 #endif
138 static int no_drop_root = 0;
139 static int wrote_pid_file = 0;
140 static char *action_script = NULL;
141
142 static enum {
143 DAEMON_RUN,
144 DAEMON_KILL,
145 DAEMON_REFRESH,
146 DAEMON_VERSION,
147 DAEMON_HELP,
148 DAEMON_CHECK
149 } command = DAEMON_RUN;
150
151 typedef enum CalloutEvent {
152 CALLOUT_BIND,
153 CALLOUT_CONFLICT,
154 CALLOUT_UNBIND,
155 CALLOUT_STOP,
156 CALLOUT_MAX
157 } CalloutEvent;
158
159 static const char * const callout_event_table[CALLOUT_MAX] = {
160 [CALLOUT_BIND] = "BIND",
161 [CALLOUT_CONFLICT] = "CONFLICT",
162 [CALLOUT_UNBIND] = "UNBIND",
163 [CALLOUT_STOP] = "STOP"
164 };
165
166 typedef struct CalloutEventInfo {
167 CalloutEvent event;
168 uint32_t address;
169 int ifindex;
170 } CalloutEventInfo;
171
172 #define RANDOM_DEVICE "/dev/urandom"
173
174 #define DEBUG(x) \
175 do { \
176 if (debug) { \
177 x; \
178 } \
179 } while (0)
180
init_rand_seed(void)181 static void init_rand_seed(void) {
182 int fd;
183 unsigned seed = 0;
184
185 /* Try to initialize seed from /dev/urandom, to make it a little
186 * less predictable, and to make sure that multiple machines
187 * booted at the same time choose different random seeds. */
188 if ((fd = open(RANDOM_DEVICE, O_RDONLY)) >= 0) {
189 read(fd, &seed, sizeof(seed));
190 close(fd);
191 }
192
193 /* If the initialization failed by some reason, we add the time to the seed */
194 seed ^= (unsigned) time(NULL);
195
196 srand(seed);
197 }
198
pick_addr(uint32_t old_addr)199 static uint32_t pick_addr(uint32_t old_addr) {
200 uint32_t addr;
201
202 do {
203 unsigned r = (unsigned) rand();
204
205 /* Reduce to 16 bits */
206 while (r > 0xFFFF)
207 r = (r >> 16) ^ (r & 0xFFFF);
208
209 addr = htonl(IPV4LL_NETWORK | (uint32_t) r);
210
211 } while (addr == old_addr || !is_ll_address(addr));
212
213 return addr;
214 }
215
load_address(const char * fn,uint32_t * addr)216 static int load_address(const char *fn, uint32_t *addr) {
217 FILE *f;
218 unsigned a, b, c, d;
219
220 assert(fn);
221 assert(addr);
222
223 if (!(f = fopen(fn, "r"))) {
224
225 if (errno == ENOENT) {
226 *addr = 0;
227 return 0;
228 }
229
230 daemon_log(LOG_ERR, "fopen() failed: %s", strerror(errno));
231 goto fail;
232 }
233
234 if (fscanf(f, "%u.%u.%u.%u\n", &a, &b, &c, &d) != 4) {
235 daemon_log(LOG_ERR, "Parse failure");
236 goto fail;
237 }
238
239 fclose(f);
240
241 *addr = htonl((a << 24) | (b << 16) | (c << 8) | d);
242 return 0;
243
244 fail:
245 if (f)
246 fclose(f);
247
248 return -1;
249 }
250
save_address(const char * fn,uint32_t addr)251 static int save_address(const char *fn, uint32_t addr) {
252 FILE *f;
253 char buf[32];
254 mode_t u;
255
256 assert(fn);
257
258 u = umask(0033);
259 if (!(f = fopen(fn, "w"))) {
260 daemon_log(LOG_ERR, "fopen() failed: %s", strerror(errno));
261 goto fail;
262 }
263 umask(u);
264
265 fprintf(f, "%s\n", inet_ntop(AF_INET, &addr, buf, sizeof (buf)));
266 fclose(f);
267
268 return 0;
269
270 fail:
271 if (f)
272 fclose(f);
273
274 umask(u);
275
276 return -1;
277 }
278
279 /*
280 * Allocate a buffer with two pointers in front, one of which is
281 * guaranteed to point ETHER_HDR_SIZE bytes into it.
282 */
packet_new(size_t packet_len)283 static ArpPacket* packet_new(size_t packet_len) {
284 ArpPacket *p;
285 uint8_t *b;
286
287 assert(packet_len > 0);
288
289 #ifdef __linux__
290 b = avahi_new0(uint8_t, sizeof(struct ArpPacket) + packet_len);
291 p = (ArpPacket*) b;
292 p->ether_header = NULL;
293 p->ether_payload = b + sizeof(struct ArpPacket);
294
295 #else
296 b = avahi_new0(uint8_t, sizeof(struct ArpPacket) + ETHER_HDR_SIZE + packet_len);
297 p = (ArpPacket*) b;
298 p->ether_header = b + sizeof(struct ArpPacket);
299 p->ether_payload = b + sizeof(struct ArpPacket) + ETHER_HDR_SIZE;
300 #endif
301
302 return p;
303 }
304
packet_new_with_info(const ArpPacketInfo * info,size_t * packet_len)305 static ArpPacket* packet_new_with_info(const ArpPacketInfo *info, size_t *packet_len) {
306 ArpPacket *p = NULL;
307 uint8_t *r;
308
309 assert(info);
310 assert(info->operation == ARP_REQUEST || info->operation == ARP_RESPONSE);
311 assert(packet_len != NULL);
312
313 *packet_len = ARP_PACKET_SIZE;
314 p = packet_new(*packet_len);
315 r = p->ether_payload;
316
317 r[1] = 1; /* HTYPE */
318 r[2] = 8; /* PTYPE */
319 r[4] = ETHER_ADDRLEN; /* HLEN */
320 r[5] = 4; /* PLEN */
321 r[7] = (uint8_t) info->operation;
322
323 memcpy(r+8, info->sender_hw_address, ETHER_ADDRLEN);
324 memcpy(r+14, &info->sender_ip_address, 4);
325 memcpy(r+18, info->target_hw_address, ETHER_ADDRLEN);
326 memcpy(r+24, &info->target_ip_address, 4);
327
328 return p;
329 }
330
packet_new_probe(uint32_t ip_address,const uint8_t * hw_address,size_t * packet_len)331 static ArpPacket *packet_new_probe(uint32_t ip_address, const uint8_t*hw_address, size_t *packet_len) {
332 ArpPacketInfo info;
333
334 memset(&info, 0, sizeof(info));
335 info.operation = ARP_REQUEST;
336 memcpy(info.sender_hw_address, hw_address, ETHER_ADDRLEN);
337 info.target_ip_address = ip_address;
338
339 return packet_new_with_info(&info, packet_len);
340 }
341
packet_new_announcement(uint32_t ip_address,const uint8_t * hw_address,size_t * packet_len)342 static ArpPacket *packet_new_announcement(uint32_t ip_address, const uint8_t* hw_address, size_t *packet_len) {
343 ArpPacketInfo info;
344
345 memset(&info, 0, sizeof(info));
346 info.operation = ARP_REQUEST;
347 memcpy(info.sender_hw_address, hw_address, ETHER_ADDRLEN);
348 info.target_ip_address = ip_address;
349 info.sender_ip_address = ip_address;
350
351 return packet_new_with_info(&info, packet_len);
352 }
353
packet_parse(const ArpPacket * packet,size_t packet_len,ArpPacketInfo * info)354 static int packet_parse(const ArpPacket *packet, size_t packet_len, ArpPacketInfo *info) {
355 const uint8_t *p;
356
357 assert(packet);
358 p = (uint8_t *)packet->ether_payload;
359 assert(p);
360
361 if (packet_len < ARP_PACKET_SIZE)
362 return -1;
363
364 /* Check HTYPE and PTYPE */
365 if (p[0] != 0 || p[1] != 1 || p[2] != 8 || p[3] != 0)
366 return -1;
367
368 /* Check HLEN, PLEN, OPERATION */
369 if (p[4] != ETHER_ADDRLEN || p[5] != 4 || p[6] != 0 || (p[7] != 1 && p[7] != 2))
370 return -1;
371
372 info->operation = p[7];
373 memcpy(info->sender_hw_address, p+8, ETHER_ADDRLEN);
374 memcpy(&info->sender_ip_address, p+14, 4);
375 memcpy(info->target_hw_address, p+18, ETHER_ADDRLEN);
376 memcpy(&info->target_ip_address, p+24, 4);
377
378 return 0;
379 }
380
set_state(State st,int reset_counter,uint32_t address)381 static void set_state(State st, int reset_counter, uint32_t address) {
382 static const char* const state_table[] = {
383 [STATE_START] = "START",
384 [STATE_WAITING_PROBE] = "WAITING_PROBE",
385 [STATE_PROBING] = "PROBING",
386 [STATE_WAITING_ANNOUNCE] = "WAITING_ANNOUNCE",
387 [STATE_ANNOUNCING] = "ANNOUNCING",
388 [STATE_RUNNING] = "RUNNING",
389 [STATE_SLEEPING] = "SLEEPING"
390 };
391 char buf[64];
392
393 assert(st < STATE_MAX);
394
395 if (st == state && !reset_counter) {
396 n_iteration++;
397 DEBUG(daemon_log(LOG_DEBUG, "State iteration %s-%i", state_table[state], n_iteration));
398 } else {
399 DEBUG(daemon_log(LOG_DEBUG, "State transition %s-%i -> %s-0", state_table[state], n_iteration, state_table[st]));
400 state = st;
401 n_iteration = 0;
402 }
403
404 if (state == STATE_SLEEPING)
405 avahi_set_proc_title(argv0, "%s: [%s] sleeping", argv0, interface_name);
406 else if (state == STATE_ANNOUNCING)
407 avahi_set_proc_title(argv0, "%s: [%s] announcing %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
408 else if (state == STATE_RUNNING)
409 avahi_set_proc_title(argv0, "%s: [%s] bound %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
410 else
411 avahi_set_proc_title(argv0, "%s: [%s] probing %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
412 }
413
interface_up(int iface)414 static int interface_up(int iface) {
415 int fd = -1;
416 struct ifreq ifreq;
417
418 if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
419 daemon_log(LOG_ERR, "socket() failed: %s", strerror(errno));
420 goto fail;
421 }
422
423 memset(&ifreq, 0, sizeof(ifreq));
424 if (!if_indextoname(iface, ifreq.ifr_name)) {
425 daemon_log(LOG_ERR, "if_indextoname() failed: %s", strerror(errno));
426 goto fail;
427 }
428
429 if (ioctl(fd, SIOCGIFFLAGS, &ifreq) < 0) {
430 daemon_log(LOG_ERR, "SIOCGIFFLAGS failed: %s", strerror(errno));
431 goto fail;
432 }
433
434 ifreq.ifr_flags |= IFF_UP;
435
436 if (ioctl(fd, SIOCSIFFLAGS, &ifreq) < 0) {
437 daemon_log(LOG_ERR, "SIOCSIFFLAGS failed: %s", strerror(errno));
438 goto fail;
439 }
440
441 close(fd);
442
443 return 0;
444
445 fail:
446 if (fd >= 0)
447 close(fd);
448
449 return -1;
450 }
451
452 #ifdef __linux__
453
454 /* Linux 'packet socket' specific implementation */
455
open_socket(int iface,uint8_t * hw_address)456 static int open_socket(int iface, uint8_t *hw_address) {
457 int fd = -1;
458 struct sockaddr_ll sa;
459 socklen_t sa_len;
460
461 if (interface_up(iface) < 0)
462 goto fail;
463
464 if ((fd = socket(PF_PACKET, SOCK_DGRAM, 0)) < 0) {
465 daemon_log(LOG_ERR, "socket() failed: %s", strerror(errno));
466 goto fail;
467 }
468
469 memset(&sa, 0, sizeof(sa));
470 sa.sll_family = AF_PACKET;
471 sa.sll_protocol = htons(ETH_P_ARP);
472 sa.sll_ifindex = iface;
473
474 if (bind(fd, (struct sockaddr*) &sa, sizeof(sa)) < 0) {
475 daemon_log(LOG_ERR, "bind() failed: %s", strerror(errno));
476 goto fail;
477 }
478
479 sa_len = sizeof(sa);
480 if (getsockname(fd, (struct sockaddr*) &sa, &sa_len) < 0) {
481 daemon_log(LOG_ERR, "getsockname() failed: %s", strerror(errno));
482 goto fail;
483 }
484
485 if (sa.sll_halen != ETHER_ADDRLEN) {
486 daemon_log(LOG_ERR, "getsockname() returned invalid hardware address.");
487 goto fail;
488 }
489
490 memcpy(hw_address, sa.sll_addr, ETHER_ADDRLEN);
491
492 return fd;
493
494 fail:
495 if (fd >= 0)
496 close(fd);
497
498 return -1;
499 }
500
send_packet(int fd,int iface,ArpPacket * packet,size_t packet_len)501 static int send_packet(int fd, int iface, ArpPacket *packet, size_t packet_len) {
502 struct sockaddr_ll sa;
503
504 assert(fd >= 0);
505 assert(packet);
506 assert(packet_len > 0);
507
508 memset(&sa, 0, sizeof(sa));
509 sa.sll_family = AF_PACKET;
510 sa.sll_protocol = htons(ETH_P_ARP);
511 sa.sll_ifindex = iface;
512 sa.sll_halen = ETHER_ADDRLEN;
513 memset(sa.sll_addr, 0xFF, ETHER_ADDRLEN);
514
515 if (sendto(fd, packet->ether_payload, packet_len, 0, (struct sockaddr*) &sa, sizeof(sa)) < 0) {
516 daemon_log(LOG_ERR, "sendto() failed: %s", strerror(errno));
517 return -1;
518 }
519
520 return 0;
521 }
522
recv_packet(int fd,ArpPacket ** packet,size_t * packet_len)523 static int recv_packet(int fd, ArpPacket **packet, size_t *packet_len) {
524 int s;
525 struct sockaddr_ll sa;
526 socklen_t sa_len;
527 ssize_t r;
528
529 assert(fd >= 0);
530 assert(packet);
531 assert(packet_len);
532
533 *packet = NULL;
534
535 if (ioctl(fd, FIONREAD, &s) < 0) {
536 daemon_log(LOG_ERR, "FIONREAD failed: %s", strerror(errno));
537 goto fail;
538 }
539
540 if (s <= 0)
541 s = 4096;
542
543 *packet = packet_new(s);
544
545 sa_len = sizeof(sa);
546 if ((r = recvfrom(fd, (*packet)->ether_payload, s, 0, (struct sockaddr*) &sa, &sa_len)) < 0) {
547 daemon_log(LOG_ERR, "recvfrom() failed: %s", strerror(errno));
548 goto fail;
549 }
550
551 *packet_len = (size_t) r;
552
553 return 0;
554
555 fail:
556 if (*packet) {
557 avahi_free(*packet);
558 *packet = NULL;
559 }
560
561 return -1;
562 }
563
close_socket(int fd)564 static void close_socket(int fd) {
565 close(fd);
566 }
567
568 #else /* !__linux__ */
569 /* PCAP-based implementation */
570
571 static pcap_t *__pp;
572 static char __pcap_errbuf[PCAP_ERRBUF_SIZE];
573 static uint8_t __lladdr[ETHER_ADDRLEN];
574
575 #ifndef elementsof
576 #define elementsof(array) (sizeof(array)/sizeof(array[0]))
577 #endif
578
__get_ether_addr(int ifindex,u_char * lladdr)579 static int __get_ether_addr(int ifindex, u_char *lladdr) {
580 int mib[6];
581 char *buf;
582 struct if_msghdr *ifm;
583 char *lim;
584 char *next;
585 struct sockaddr_dl *sdl;
586 size_t len;
587
588 mib[0] = CTL_NET;
589 mib[1] = PF_ROUTE;
590 mib[2] = 0;
591 mib[3] = 0;
592 mib[4] = NET_RT_IFLIST;
593 mib[5] = ifindex;
594
595 if (sysctl(mib, elementsof(mib), NULL, &len, NULL, 0) != 0) {
596 daemon_log(LOG_ERR, "sysctl(NET_RT_IFLIST): %s",
597 strerror(errno));
598 return -1;
599 }
600
601 buf = avahi_malloc(len);
602 if (sysctl(mib, elementsof(mib), buf, &len, NULL, 0) != 0) {
603 daemon_log(LOG_ERR, "sysctl(NET_RT_IFLIST): %s",
604 strerror(errno));
605 free(buf);
606 return -1;
607 }
608
609 lim = buf + len;
610 for (next = buf; next < lim; next += ifm->ifm_msglen) {
611 ifm = (struct if_msghdr *)next;
612 if (ifm->ifm_type == RTM_IFINFO) {
613 sdl = (struct sockaddr_dl *)(ifm + 1);
614 memcpy(lladdr, LLADDR(sdl), ETHER_ADDRLEN);
615 }
616 }
617 avahi_free(buf);
618
619 return 0;
620 }
621
622 #define PCAP_TIMEOUT 500 /* 0.5s */
623
open_socket(int iface,uint8_t * hw_address)624 static int open_socket(int iface, uint8_t *hw_address) {
625 struct bpf_program bpf;
626 char *filter;
627 char ifname[IFNAMSIZ];
628 pcap_t *pp;
629 int err;
630 int fd;
631
632 assert(__pp == NULL);
633
634 if (interface_up(iface) < 0)
635 return -1;
636
637 if (__get_ether_addr(iface, __lladdr) == -1)
638 return -1;
639
640 if (if_indextoname(iface, ifname) == NULL)
641 return -1;
642
643 /*
644 * Using a timeout for BPF is fairly portable across BSDs. On most
645 * modern versions, using the timeout/nonblock/poll method results in
646 * fairly sane behavior, with the timeout only coming into play during
647 * the next_ex() call itself (so, for us, that's only when there's
648 * data). On older versions, it may result in a PCAP_TIMEOUT busy-wait
649 * on some versions, though, as the poll() may terminate at the
650 * PCAP_TIMEOUT instead of the poll() timeout.
651 */
652 pp = pcap_open_live(ifname, 1500, 0, PCAP_TIMEOUT, __pcap_errbuf);
653 if (pp == NULL) {
654 return (-1);
655 }
656 err = pcap_set_datalink(pp, DLT_EN10MB);
657 if (err == -1) {
658 daemon_log(LOG_ERR, "pcap_set_datalink: %s", pcap_geterr(pp));
659 pcap_close(pp);
660 return (-1);
661 }
662 err = pcap_setdirection(pp, PCAP_D_IN);
663 if (err == -1) {
664 daemon_log(LOG_ERR, "pcap_setdirection: %s", pcap_geterr(pp));
665 pcap_close(pp);
666 return (-1);
667 }
668
669 fd = pcap_get_selectable_fd(pp);
670 if (fd == -1) {
671 pcap_close(pp);
672 return (-1);
673 }
674
675 /*
676 * Using setnonblock is a portability stop-gap. Using the timeout in
677 * combination with setnonblock will ensure on most BSDs that the
678 * next_ex call returns in a timely fashion.
679 */
680 err = pcap_setnonblock(pp, 1, __pcap_errbuf);
681 if (err == -1) {
682 pcap_close(pp);
683 return (-1);
684 }
685
686 filter = avahi_strdup_printf("arp and (ether dst ff:ff:ff:ff:ff:ff or "
687 "%02x:%02x:%02x:%02x:%02x:%02x)",
688 __lladdr[0], __lladdr[1],
689 __lladdr[2], __lladdr[3],
690 __lladdr[4], __lladdr[5]);
691 DEBUG(daemon_log(LOG_DEBUG, "Using pcap filter '%s'", filter));
692
693 err = pcap_compile(pp, &bpf, filter, 1, 0);
694 avahi_free(filter);
695 if (err == -1) {
696 daemon_log(LOG_ERR, "pcap_compile: %s", pcap_geterr(pp));
697 pcap_close(pp);
698 return (-1);
699 }
700 err = pcap_setfilter(pp, &bpf);
701 if (err == -1) {
702 daemon_log(LOG_ERR, "pcap_setfilter: %s", pcap_geterr(pp));
703 pcap_close(pp);
704 return (-1);
705 }
706 pcap_freecode(&bpf);
707
708 /* Stash pcap-specific context away. */
709 memcpy(hw_address, __lladdr, ETHER_ADDRLEN);
710 __pp = pp;
711
712 return (fd);
713 }
714
close_socket(int fd AVAHI_GCC_UNUSED)715 static void close_socket(int fd AVAHI_GCC_UNUSED) {
716 assert(__pp != NULL);
717 pcap_close(__pp);
718 __pp = NULL;
719 }
720
721 /*
722 * We trick avahi into allocating sizeof(packet) + sizeof(ether_header),
723 * and prepend the required ethernet header information before sending.
724 */
send_packet(int fd AVAHI_GCC_UNUSED,int iface AVAHI_GCC_UNUSED,ArpPacket * packet,size_t packet_len)725 static int send_packet(int fd AVAHI_GCC_UNUSED, int iface AVAHI_GCC_UNUSED, ArpPacket *packet, size_t packet_len) {
726 struct ether_header *eh;
727
728 assert(__pp != NULL);
729 assert(packet != NULL);
730
731 eh = (struct ether_header *)packet->ether_header;
732 memset(eh->ether_dhost, 0xFF, ETHER_ADDRLEN);
733 memcpy(eh->ether_shost, __lladdr, ETHER_ADDRLEN);
734 eh->ether_type = htons(0x0806);
735
736 return (pcap_inject(__pp, (void *)eh, packet_len + sizeof(*eh)));
737 }
738
recv_packet(int fd AVAHI_GCC_UNUSED,ArpPacket ** packet,size_t * packet_len)739 static int recv_packet(int fd AVAHI_GCC_UNUSED, ArpPacket **packet, size_t *packet_len) {
740 struct pcap_pkthdr *ph;
741 u_char *pd;
742 ArpPacket *ap;
743 int err;
744 int retval;
745
746 assert(__pp != NULL);
747 assert(packet != NULL);
748 assert(packet_len != NULL);
749
750 *packet = NULL;
751 *packet_len = 0;
752 retval = -1;
753
754 err = pcap_next_ex(__pp, &ph, (const u_char **)&pd);
755 if (err == 1 && ph->caplen <= ph->len) {
756 ap = packet_new(ph->caplen);
757 memcpy(ap->ether_header, pd, ph->caplen);
758 *packet = ap;
759 *packet_len = (ph->caplen - sizeof(struct ether_header));
760 retval = 0;
761 } else if (err >= 0) {
762 /*
763 * err == 1: Just drop bogus packets (>1500 for an arp packet!?)
764 * on the floor.
765 *
766 * err == 0: We might have had traffic on the pcap fd that
767 * didn't match the filter, in which case we'll get 0 packets.
768 */
769 retval = 0;
770 } else
771 daemon_log(LOG_ERR, "pcap_next_ex(%d): %s",
772 err, pcap_geterr(__pp));
773
774 return (retval);
775 }
776 #endif /* __linux__ */
777
is_ll_address(uint32_t addr)778 int is_ll_address(uint32_t addr) {
779 return
780 ((ntohl(addr) & IPV4LL_NETMASK) == IPV4LL_NETWORK) &&
781 ((ntohl(addr) & 0x0000FF00) != 0x0000) &&
782 ((ntohl(addr) & 0x0000FF00) != 0xFF00);
783 }
784
elapse_time(struct timeval * tv,unsigned msec,unsigned jitter)785 static struct timeval *elapse_time(struct timeval *tv, unsigned msec, unsigned jitter) {
786 assert(tv);
787
788 gettimeofday(tv, NULL);
789
790 if (msec)
791 avahi_timeval_add(tv, (AvahiUsec) msec*1000);
792
793 if (jitter)
794 avahi_timeval_add(tv, (AvahiUsec) (jitter*1000.0*rand()/(RAND_MAX+1.0)));
795
796 return tv;
797 }
798
fork_dispatcher(void)799 static FILE* fork_dispatcher(void) {
800 FILE *ret;
801 int fds[2];
802 pid_t pid;
803
804 if (pipe(fds) < 0) {
805 daemon_log(LOG_ERR, "pipe() failed: %s", strerror(errno));
806 goto fail;
807 }
808
809 if ((pid = fork()) < 0)
810 goto fail;
811 else if (pid == 0) {
812 FILE *f = NULL;
813 int r = 1;
814
815 /* Please note that the signal pipe is not closed at this
816 * point, signals will thus be dispatched in the main
817 * process. */
818
819 daemon_retval_done();
820
821 avahi_set_proc_title(argv0, "%s: [%s] callout dispatcher", argv0, interface_name);
822
823 close(fds[1]);
824
825 if (!(f = fdopen(fds[0], "r"))) {
826 daemon_log(LOG_ERR, "fdopen() failed: %s", strerror(errno));
827 goto dispatcher_fail;
828 }
829
830 for (;;) {
831 CalloutEventInfo info;
832 char name[IFNAMSIZ], buf[64];
833 int k;
834
835 if (fread(&info, sizeof(info), 1, f) != 1) {
836 if (feof(f))
837 break;
838
839 daemon_log(LOG_ERR, "fread() failed: %s", strerror(errno));
840 goto dispatcher_fail;
841 }
842
843 assert(info.event <= CALLOUT_MAX);
844
845 if (!if_indextoname(info.ifindex, name)) {
846 daemon_log(LOG_ERR, "if_indextoname() failed: %s", strerror(errno));
847 continue;
848 }
849
850 if (daemon_exec("/", &k,
851 action_script, action_script,
852 callout_event_table[info.event],
853 name,
854 inet_ntop(AF_INET, &info.address, buf, sizeof(buf)), NULL) < 0) {
855
856 daemon_log(LOG_ERR, "Failed to run script: %s", strerror(errno));
857 continue;
858 }
859
860 if (k != 0)
861 daemon_log(LOG_WARNING, "Script execution failed with return value %i", k);
862 }
863
864 r = 0;
865
866 dispatcher_fail:
867
868 if (f)
869 fclose(f);
870
871 #ifdef HAVE_CHROOT
872 /* If the main process is trapped inside a chroot() we have to
873 * remove the PID file for it */
874
875 if (!no_chroot && wrote_pid_file)
876 daemon_pid_file_remove();
877 #endif
878
879 _exit(r);
880 }
881
882 /* parent */
883
884 close(fds[0]);
885 fds[0] = -1;
886
887 if (!(ret = fdopen(fds[1], "w"))) {
888 daemon_log(LOG_ERR, "fdopen() failed: %s", strerror(errno));
889 goto fail;
890 }
891
892 return ret;
893
894 fail:
895 if (fds[0] >= 0)
896 close(fds[0]);
897 if (fds[1] >= 0)
898 close(fds[1]);
899
900 return NULL;
901 }
902
do_callout(FILE * f,CalloutEvent event,int iface,uint32_t addr)903 static int do_callout(FILE *f, CalloutEvent event, int iface, uint32_t addr) {
904 CalloutEventInfo info;
905 char buf[64], ifname[IFNAMSIZ];
906
907 daemon_log(LOG_INFO, "Callout %s, address %s on interface %s",
908 callout_event_table[event],
909 inet_ntop(AF_INET, &addr, buf, sizeof(buf)),
910 if_indextoname(iface, ifname));
911
912 info.event = event;
913 info.ifindex = iface;
914 info.address = addr;
915
916 if (fwrite(&info, sizeof(info), 1, f) != 1 || fflush(f) != 0) {
917 daemon_log(LOG_ERR, "Failed to write callout event: %s", strerror(errno));
918 return -1;
919 }
920
921 return 0;
922 }
923
924 #define set_env(key, value) putenv(avahi_strdup_printf("%s=%s", (key), (value)))
925
drop_privs(void)926 static int drop_privs(void) {
927 struct passwd *pw;
928 struct group * gr;
929 int r;
930 mode_t u;
931
932 pw = NULL;
933 gr = NULL;
934
935 /* Get user/group ID */
936
937 if (!no_drop_root) {
938
939 if (!(pw = getpwnam(AVAHI_AUTOIPD_USER))) {
940 daemon_log(LOG_ERR, "Failed to find user '"AVAHI_AUTOIPD_USER"'.");
941 return -1;
942 }
943
944 if (!(gr = getgrnam(AVAHI_AUTOIPD_GROUP))) {
945 daemon_log(LOG_ERR, "Failed to find group '"AVAHI_AUTOIPD_GROUP"'.");
946 return -1;
947 }
948
949 daemon_log(LOG_INFO, "Found user '"AVAHI_AUTOIPD_USER"' (UID %lu) and group '"AVAHI_AUTOIPD_GROUP"' (GID %lu).", (unsigned long) pw->pw_uid, (unsigned long) gr->gr_gid);
950 }
951
952 /* Create directory */
953 u = umask(0000);
954 r = mkdir(AVAHI_IPDATA_DIR, 0755);
955 umask(u);
956
957 if (r < 0 && errno != EEXIST) {
958 daemon_log(LOG_ERR, "mkdir(\""AVAHI_IPDATA_DIR"\"): %s", strerror(errno));
959 return -1;
960 }
961
962 /* Convey working directory */
963
964 if (!no_drop_root) {
965 struct stat st;
966
967 chown(AVAHI_IPDATA_DIR, pw->pw_uid, gr->gr_gid);
968
969 if (stat(AVAHI_IPDATA_DIR, &st) < 0) {
970 daemon_log(LOG_ERR, "stat(): %s\n", strerror(errno));
971 return -1;
972 }
973
974 if (!S_ISDIR(st.st_mode) || st.st_uid != pw->pw_uid || st.st_gid != gr->gr_gid) {
975 daemon_log(LOG_ERR, "Failed to create runtime directory "AVAHI_IPDATA_DIR".");
976 return -1;
977 }
978 }
979
980 #ifdef HAVE_CHROOT
981
982 if (!no_chroot) {
983 if (chroot(AVAHI_IPDATA_DIR) < 0) {
984 daemon_log(LOG_ERR, "Failed to chroot(): %s", strerror(errno));
985 return -1;
986 }
987
988 daemon_log(LOG_INFO, "Successfully called chroot().");
989 chdir("/");
990
991 /* Since we are now trapped inside a chroot we cannot remove
992 * the pid file anymore, the helper process will do that for us. */
993 wrote_pid_file = 0;
994 }
995
996 #endif
997
998 if (!no_drop_root) {
999
1000 if (initgroups(AVAHI_AUTOIPD_USER, gr->gr_gid) != 0) {
1001 daemon_log(LOG_ERR, "Failed to change group list: %s", strerror(errno));
1002 return -1;
1003 }
1004
1005 #if defined(HAVE_SETRESGID)
1006 r = setresgid(gr->gr_gid, gr->gr_gid, gr->gr_gid);
1007 #elif defined(HAVE_SETEGID)
1008 if ((r = setgid(gr->gr_gid)) >= 0)
1009 r = setegid(gr->gr_gid);
1010 #elif defined(HAVE_SETREGID)
1011 r = setregid(gr->gr_gid, gr->gr_gid);
1012 #else
1013 #error "No API to drop privileges"
1014 #endif
1015
1016 if (r < 0) {
1017 daemon_log(LOG_ERR, "Failed to change GID: %s", strerror(errno));
1018 return -1;
1019 }
1020
1021 #if defined(HAVE_SETRESUID)
1022 r = setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid);
1023 #elif defined(HAVE_SETEUID)
1024 if ((r = setuid(pw->pw_uid)) >= 0)
1025 r = seteuid(pw->pw_uid);
1026 #elif defined(HAVE_SETREUID)
1027 r = setreuid(pw->pw_uid, pw->pw_uid);
1028 #else
1029 #error "No API to drop privileges"
1030 #endif
1031
1032 if (r < 0) {
1033 daemon_log(LOG_ERR, "Failed to change UID: %s", strerror(errno));
1034 return -1;
1035 }
1036
1037 set_env("USER", pw->pw_name);
1038 set_env("LOGNAME", pw->pw_name);
1039 set_env("HOME", pw->pw_dir);
1040
1041 daemon_log(LOG_INFO, "Successfully dropped root privileges.");
1042 }
1043
1044 return 0;
1045 }
1046
loop(int iface,uint32_t addr)1047 static int loop(int iface, uint32_t addr) {
1048 enum {
1049 FD_ARP,
1050 FD_IFACE,
1051 FD_SIGNAL,
1052 FD_MAX
1053 };
1054
1055 int fd = -1, ret = -1;
1056 struct timeval next_wakeup;
1057 int next_wakeup_valid = 0;
1058 char buf[64];
1059 ArpPacket *in_packet = NULL;
1060 size_t in_packet_len = 0;
1061 ArpPacket *out_packet = NULL;
1062 size_t out_packet_len;
1063 uint8_t hw_address[ETHER_ADDRLEN];
1064 struct pollfd pollfds[FD_MAX];
1065 int iface_fd = -1;
1066 Event event = EVENT_NULL;
1067 int retval_sent = !daemonize;
1068 State st;
1069 FILE *dispatcher = NULL;
1070 char *address_fn = NULL;
1071 const char *p;
1072
1073 daemon_signal_init(SIGINT, SIGTERM, SIGCHLD, SIGHUP, 0);
1074
1075 if (!(dispatcher = fork_dispatcher()))
1076 goto fail;
1077
1078 if ((fd = open_socket(iface, hw_address)) < 0)
1079 goto fail;
1080
1081 if ((iface_fd = iface_init(iface)) < 0)
1082 goto fail;
1083
1084 if (drop_privs() < 0)
1085 goto fail;
1086
1087 if (force_bind)
1088 st = STATE_START;
1089 else if (iface_get_initial_state(&st) < 0)
1090 goto fail;
1091
1092 #ifdef HAVE_CHROOT
1093 if (!no_chroot)
1094 p = "";
1095 else
1096 #endif
1097 p = AVAHI_IPDATA_DIR;
1098
1099 address_fn = avahi_strdup_printf(
1100 "%s/%02x:%02x:%02x:%02x:%02x:%02x", p,
1101 hw_address[0], hw_address[1],
1102 hw_address[2], hw_address[3],
1103 hw_address[4], hw_address[5]);
1104
1105 if (!addr)
1106 load_address(address_fn, &addr);
1107
1108 if (addr && !is_ll_address(addr)) {
1109 daemon_log(LOG_WARNING, "Requested address %s is not from IPv4LL range 169.254/16 or a reserved address, ignoring.", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
1110 addr = 0;
1111 }
1112
1113 if (!addr) {
1114 int i;
1115 uint32_t a = 1;
1116
1117 for (i = 0; i < ETHER_ADDRLEN; i++)
1118 a += hw_address[i]*(i+1);
1119
1120 a = (a % 0xFE00) + 0x0100;
1121
1122 addr = htonl(IPV4LL_NETWORK | (uint32_t) a);
1123 }
1124
1125 assert(is_ll_address(addr));
1126
1127 set_state(st, 1, addr);
1128
1129 daemon_log(LOG_INFO, "Starting with address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
1130
1131 if (state == STATE_SLEEPING)
1132 daemon_log(LOG_INFO, "Routable address already assigned, sleeping.");
1133
1134 if (!retval_sent && (!wait_for_address || state == STATE_SLEEPING)) {
1135 daemon_retval_send(0);
1136 retval_sent = 1;
1137 }
1138
1139 memset(pollfds, 0, sizeof(pollfds));
1140 pollfds[FD_ARP].fd = fd;
1141 pollfds[FD_ARP].events = POLLIN;
1142 pollfds[FD_IFACE].fd = iface_fd;
1143 pollfds[FD_IFACE].events = POLLIN;
1144 pollfds[FD_SIGNAL].fd = daemon_signal_fd();
1145 pollfds[FD_SIGNAL].events = POLLIN;
1146
1147 for (;;) {
1148 int r, timeout;
1149 AvahiUsec usec;
1150
1151 if (state == STATE_START) {
1152
1153 /* First, wait a random time */
1154 set_state(STATE_WAITING_PROBE, 1, addr);
1155
1156 elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
1157 next_wakeup_valid = 1;
1158
1159 } else if ((state == STATE_WAITING_PROBE && event == EVENT_TIMEOUT) ||
1160 (state == STATE_PROBING && event == EVENT_TIMEOUT && n_iteration < PROBE_NUM-2)) {
1161
1162 /* Send a probe */
1163 out_packet = packet_new_probe(addr, hw_address, &out_packet_len);
1164 set_state(STATE_PROBING, 0, addr);
1165
1166 elapse_time(&next_wakeup, PROBE_MIN*1000, (PROBE_MAX-PROBE_MIN)*1000);
1167 next_wakeup_valid = 1;
1168
1169 } else if (state == STATE_PROBING && event == EVENT_TIMEOUT && n_iteration >= PROBE_NUM-2) {
1170
1171 /* Send the last probe */
1172 out_packet = packet_new_probe(addr, hw_address, &out_packet_len);
1173 set_state(STATE_WAITING_ANNOUNCE, 1, addr);
1174
1175 elapse_time(&next_wakeup, ANNOUNCE_WAIT*1000, 0);
1176 next_wakeup_valid = 1;
1177
1178 } else if ((state == STATE_WAITING_ANNOUNCE && event == EVENT_TIMEOUT) ||
1179 (state == STATE_ANNOUNCING && event == EVENT_TIMEOUT && n_iteration < ANNOUNCE_NUM-1)) {
1180
1181 /* Send announcement packet */
1182 out_packet = packet_new_announcement(addr, hw_address, &out_packet_len);
1183 set_state(STATE_ANNOUNCING, 0, addr);
1184
1185 elapse_time(&next_wakeup, ANNOUNCE_INTERVAL*1000, 0);
1186 next_wakeup_valid = 1;
1187
1188 if (n_iteration == 0) {
1189 if (do_callout(dispatcher, CALLOUT_BIND, iface, addr) < 0)
1190 goto fail;
1191
1192 n_conflict = 0;
1193 }
1194
1195 } else if ((state == STATE_ANNOUNCING && event == EVENT_TIMEOUT && n_iteration >= ANNOUNCE_NUM-1)) {
1196
1197 daemon_log(LOG_INFO, "Successfully claimed IP address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
1198 set_state(STATE_RUNNING, 0, addr);
1199
1200 next_wakeup_valid = 0;
1201
1202 save_address(address_fn, addr);
1203
1204 if (!retval_sent) {
1205 daemon_retval_send(0);
1206 retval_sent = 1;
1207 }
1208
1209 } else if (event == EVENT_PACKET) {
1210 ArpPacketInfo info;
1211
1212 assert(in_packet);
1213
1214 if (packet_parse(in_packet, in_packet_len, &info) < 0)
1215 daemon_log(LOG_WARNING, "Failed to parse incoming ARP packet.");
1216 else {
1217 int conflict = 0;
1218
1219 if (info.sender_ip_address == addr) {
1220
1221 if (memcmp(hw_address, info.sender_hw_address, ETHER_ADDRLEN)) {
1222 /* Normal conflict */
1223 conflict = 1;
1224 daemon_log(LOG_INFO, "Received conflicting normal ARP packet.");
1225 } else
1226 daemon_log(LOG_DEBUG, "Received ARP packet back on source interface. Ignoring.");
1227
1228 } else if (state == STATE_WAITING_PROBE || state == STATE_PROBING || state == STATE_WAITING_ANNOUNCE) {
1229 /* Probe conflict */
1230 conflict = info.target_ip_address == addr &&
1231 info.sender_ip_address == 0 &&
1232 memcmp(hw_address, info.sender_hw_address, ETHER_ADDRLEN);
1233
1234 if (conflict)
1235 daemon_log(LOG_INFO, "Received conflicting probe ARP packet.");
1236 }
1237
1238 if (conflict) {
1239
1240 if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
1241 if (do_callout(dispatcher, CALLOUT_CONFLICT, iface, addr) < 0)
1242 goto fail;
1243
1244 /* Pick a new address */
1245 addr = pick_addr(addr);
1246
1247 daemon_log(LOG_INFO, "Trying address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
1248
1249 n_conflict++;
1250
1251 set_state(STATE_WAITING_PROBE, 1, addr);
1252
1253 if (n_conflict >= MAX_CONFLICTS) {
1254 daemon_log(LOG_WARNING, "Got too many conflicts, rate limiting new probes.");
1255 elapse_time(&next_wakeup, RATE_LIMIT_INTERVAL*1000, PROBE_WAIT*1000);
1256 } else
1257 elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
1258
1259 next_wakeup_valid = 1;
1260 } else
1261 DEBUG(daemon_log(LOG_DEBUG, "Ignoring irrelevant ARP packet."));
1262 }
1263
1264 } else if (event == EVENT_ROUTABLE_ADDR_CONFIGURED && !force_bind) {
1265
1266 daemon_log(LOG_INFO, "A routable address has been configured.");
1267
1268 if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
1269 if (do_callout(dispatcher, CALLOUT_UNBIND, iface, addr) < 0)
1270 goto fail;
1271
1272 if (!retval_sent) {
1273 daemon_retval_send(0);
1274 retval_sent = 1;
1275 }
1276
1277 set_state(STATE_SLEEPING, 1, addr);
1278 next_wakeup_valid = 0;
1279
1280 } else if (event == EVENT_ROUTABLE_ADDR_UNCONFIGURED && state == STATE_SLEEPING && !force_bind) {
1281
1282 daemon_log(LOG_INFO, "No longer a routable address configured, restarting probe process.");
1283
1284 set_state(STATE_WAITING_PROBE, 1, addr);
1285
1286 elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
1287 next_wakeup_valid = 1;
1288
1289 } else if (event == EVENT_REFRESH_REQUEST && state == STATE_RUNNING) {
1290
1291 /* The user requested a reannouncing of the address by a SIGHUP */
1292 daemon_log(LOG_INFO, "Reannouncing address.");
1293
1294 /* Send announcement packet */
1295 out_packet = packet_new_announcement(addr, hw_address, &out_packet_len);
1296 set_state(STATE_ANNOUNCING, 1, addr);
1297
1298 elapse_time(&next_wakeup, ANNOUNCE_INTERVAL*1000, 0);
1299 next_wakeup_valid = 1;
1300 }
1301
1302 if (out_packet) {
1303 DEBUG(daemon_log(LOG_DEBUG, "sending..."));
1304
1305 if (send_packet(fd, iface, out_packet, out_packet_len) < 0)
1306 goto fail;
1307
1308 avahi_free(out_packet);
1309 out_packet = NULL;
1310 }
1311
1312 if (in_packet) {
1313 avahi_free(in_packet);
1314 in_packet = NULL;
1315 }
1316
1317 event = EVENT_NULL;
1318 timeout = -1;
1319
1320 if (next_wakeup_valid) {
1321 usec = avahi_age(&next_wakeup);
1322 timeout = usec < 0 ? (int) (-usec/1000) : 0;
1323 }
1324
1325 DEBUG(daemon_log(LOG_DEBUG, "sleeping %ims", timeout));
1326
1327 while ((r = poll(pollfds, FD_MAX, timeout)) < 0 && errno == EINTR)
1328 ;
1329
1330 if (r < 0) {
1331 daemon_log(LOG_ERR, "poll() failed: %s", strerror(r));
1332 goto fail;
1333 } else if (r == 0) {
1334 event = EVENT_TIMEOUT;
1335 next_wakeup_valid = 0;
1336 } else {
1337
1338
1339 if (pollfds[FD_ARP].revents) {
1340
1341 if (pollfds[FD_ARP].revents == POLLERR) {
1342 /* The interface is probably down, let's recreate our socket */
1343
1344 close_socket(fd);
1345
1346 if ((fd = open_socket(iface, hw_address)) < 0)
1347 goto fail;
1348
1349 pollfds[FD_ARP].fd = fd;
1350
1351 } else {
1352
1353 assert(pollfds[FD_ARP].revents == POLLIN);
1354
1355 if (recv_packet(fd, &in_packet, &in_packet_len) < 0)
1356 goto fail;
1357
1358 if (in_packet)
1359 event = EVENT_PACKET;
1360 }
1361 }
1362
1363 if (event == EVENT_NULL &&
1364 pollfds[FD_IFACE].revents) {
1365
1366 assert(pollfds[FD_IFACE].revents == POLLIN);
1367
1368 if (iface_process(&event) < 0)
1369 goto fail;
1370 }
1371
1372 if (event == EVENT_NULL &&
1373 pollfds[FD_SIGNAL].revents) {
1374
1375 int sig;
1376 assert(pollfds[FD_SIGNAL].revents == POLLIN);
1377
1378 if ((sig = daemon_signal_next()) <= 0) {
1379 daemon_log(LOG_ERR, "daemon_signal_next() failed");
1380 goto fail;
1381 }
1382
1383 switch(sig) {
1384 case SIGINT:
1385 case SIGTERM:
1386 daemon_log(LOG_INFO, "Got %s, quitting.", sig == SIGINT ? "SIGINT" : "SIGTERM");
1387 ret = 0;
1388 goto fail;
1389
1390 case SIGCHLD:
1391 waitpid(-1, NULL, WNOHANG);
1392 break;
1393
1394 case SIGHUP:
1395 event = EVENT_REFRESH_REQUEST;
1396 break;
1397 }
1398
1399 }
1400 }
1401 }
1402
1403 ret = 0;
1404
1405 fail:
1406
1407 if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
1408 do_callout(dispatcher, CALLOUT_STOP, iface, addr);
1409
1410 avahi_free(out_packet);
1411 avahi_free(in_packet);
1412
1413 if (fd >= 0)
1414 close_socket(fd);
1415
1416 if (iface_fd >= 0)
1417 iface_done();
1418
1419 if (daemonize && !retval_sent)
1420 daemon_retval_send(ret);
1421
1422 if (dispatcher)
1423 fclose(dispatcher);
1424
1425 if (address_fn)
1426 avahi_free(address_fn);
1427
1428 return ret;
1429 }
1430
1431
help(FILE * f,const char * a0)1432 static void help(FILE *f, const char *a0) {
1433 fprintf(f,
1434 "%s [options] INTERFACE\n"
1435 " -h --help Show this help\n"
1436 " -D --daemonize Daemonize after startup\n"
1437 " -s --syslog Write log messages to syslog(3) instead of STDERR\n"
1438 " -k --kill Kill a running daemon\n"
1439 " -r --refresh Request a running daemon refresh its IP address\n"
1440 " -c --check Return 0 if a daemon is already running\n"
1441 " -V --version Show version\n"
1442 " -S --start=ADDRESS Start with this address from the IPv4LL range\n"
1443 " 169.254.0.0/16\n"
1444 " -t --script=script Action script to run (defaults to\n"
1445 " "AVAHI_IPCONF_SCRIPT")\n"
1446 " -w --wait Wait until an address has been acquired before\n"
1447 " daemonizing\n"
1448 " --force-bind Assign an IPv4LL address even if a routable address\n"
1449 " is already assigned\n"
1450 " --no-drop-root Don't drop privileges\n"
1451 #ifdef HAVE_CHROOT
1452 " --no-chroot Don't chroot()\n"
1453 #endif
1454 " --no-proc-title Don't modify process title\n"
1455 " --debug Increase verbosity\n",
1456 a0);
1457 }
1458
parse_command_line(int argc,char * argv[])1459 static int parse_command_line(int argc, char *argv[]) {
1460 int c;
1461
1462 enum {
1463 OPTION_NO_PROC_TITLE = 256,
1464 OPTION_FORCE_BIND,
1465 OPTION_DEBUG,
1466 OPTION_NO_DROP_ROOT,
1467 #ifdef HAVE_CHROOT
1468 OPTION_NO_CHROOT
1469 #endif
1470 };
1471
1472 static const struct option long_options[] = {
1473 { "help", no_argument, NULL, 'h' },
1474 { "daemonize", no_argument, NULL, 'D' },
1475 { "syslog", no_argument, NULL, 's' },
1476 { "kill", no_argument, NULL, 'k' },
1477 { "refresh", no_argument, NULL, 'r' },
1478 { "check", no_argument, NULL, 'c' },
1479 { "version", no_argument, NULL, 'V' },
1480 { "start", required_argument, NULL, 'S' },
1481 { "script", required_argument, NULL, 't' },
1482 { "wait", no_argument, NULL, 'w' },
1483 { "force-bind", no_argument, NULL, OPTION_FORCE_BIND },
1484 { "no-drop-root", no_argument, NULL, OPTION_NO_DROP_ROOT },
1485 #ifdef HAVE_CHROOT
1486 { "no-chroot", no_argument, NULL, OPTION_NO_CHROOT },
1487 #endif
1488 { "no-proc-title", no_argument, NULL, OPTION_NO_PROC_TITLE },
1489 { "debug", no_argument, NULL, OPTION_DEBUG },
1490 { NULL, 0, NULL, 0 }
1491 };
1492
1493 while ((c = getopt_long(argc, argv, "hDskrcVS:t:w", long_options, NULL)) >= 0) {
1494
1495 switch(c) {
1496 case 's':
1497 use_syslog = 1;
1498 break;
1499 case 'h':
1500 command = DAEMON_HELP;
1501 break;
1502 case 'D':
1503 daemonize = 1;
1504 break;
1505 case 'k':
1506 command = DAEMON_KILL;
1507 break;
1508 case 'V':
1509 command = DAEMON_VERSION;
1510 break;
1511 case 'r':
1512 command = DAEMON_REFRESH;
1513 break;
1514 case 'c':
1515 command = DAEMON_CHECK;
1516 break;
1517 case 'S':
1518
1519 if ((start_address = inet_addr(optarg)) == (uint32_t) -1) {
1520 fprintf(stderr, "Failed to parse IP address '%s'.", optarg);
1521 return -1;
1522 }
1523 break;
1524 case 't':
1525 avahi_free(action_script);
1526 action_script = avahi_strdup(optarg);
1527 break;
1528 case 'w':
1529 wait_for_address = 1;
1530 break;
1531
1532 case OPTION_NO_PROC_TITLE:
1533 modify_proc_title = 0;
1534 break;
1535
1536 case OPTION_DEBUG:
1537 debug = 1;
1538 #ifdef DAEMON_SET_VERBOSITY_AVAILABLE
1539 daemon_set_verbosity(LOG_DEBUG);
1540 #endif
1541 break;
1542
1543 case OPTION_FORCE_BIND:
1544 force_bind = 1;
1545 break;
1546
1547 case OPTION_NO_DROP_ROOT:
1548 no_drop_root = 1;
1549 break;
1550
1551 #ifdef HAVE_CHROOT
1552 case OPTION_NO_CHROOT:
1553 no_chroot = 1;
1554 break;
1555 #endif
1556
1557 default:
1558 return -1;
1559 }
1560 }
1561
1562 if (command == DAEMON_RUN ||
1563 command == DAEMON_KILL ||
1564 command == DAEMON_REFRESH ||
1565 command == DAEMON_CHECK) {
1566
1567 if (optind >= argc) {
1568 fprintf(stderr, "Missing interface name.\n");
1569 return -1;
1570 }
1571
1572 interface_name = avahi_strdup(argv[optind++]);
1573 }
1574
1575 if (optind != argc) {
1576 fprintf(stderr, "Too many arguments\n");
1577 return -1;
1578 }
1579
1580 if (!action_script)
1581 action_script = avahi_strdup(AVAHI_IPCONF_SCRIPT);
1582
1583 return 0;
1584 }
1585
pid_file_proc(void)1586 static const char* pid_file_proc(void) {
1587 return pid_file_name;
1588 }
1589
main(int argc,char * argv[])1590 int main(int argc, char*argv[]) {
1591 int r = 1;
1592 char *log_ident = NULL;
1593
1594 signal(SIGPIPE, SIG_IGN);
1595
1596 if ((argv0 = strrchr(argv[0], '/')))
1597 argv0 = avahi_strdup(argv0 + 1);
1598 else
1599 argv0 = avahi_strdup(argv[0]);
1600
1601 daemon_log_ident = argv0;
1602
1603 if (parse_command_line(argc, argv) < 0)
1604 goto finish;
1605
1606 if (modify_proc_title)
1607 avahi_init_proc_title(argc, argv);
1608
1609 daemon_log_ident = log_ident = avahi_strdup_printf("%s(%s)", argv0, interface_name);
1610 daemon_pid_file_proc = pid_file_proc;
1611 pid_file_name = avahi_strdup_printf(AVAHI_RUNTIME_DIR"/avahi-autoipd.%s.pid", interface_name);
1612
1613 if (command == DAEMON_RUN) {
1614 pid_t pid;
1615 int ifindex;
1616
1617 init_rand_seed();
1618
1619 if ((ifindex = if_nametoindex(interface_name)) <= 0) {
1620 daemon_log(LOG_ERR, "Failed to get index for interface name '%s': %s", interface_name, strerror(errno));
1621 goto finish;
1622 }
1623
1624 if (getuid() != 0) {
1625 daemon_log(LOG_ERR, "This program is intended to be run as root.");
1626 goto finish;
1627 }
1628
1629 if ((pid = daemon_pid_file_is_running()) >= 0) {
1630 daemon_log(LOG_ERR, "Daemon already running on PID %u", pid);
1631 goto finish;
1632 }
1633
1634 if (daemonize) {
1635 daemon_retval_init();
1636
1637 if ((pid = daemon_fork()) < 0)
1638 goto finish;
1639 else if (pid != 0) {
1640 int ret;
1641 /** Parent **/
1642
1643 if ((ret = daemon_retval_wait(20)) < 0) {
1644 daemon_log(LOG_ERR, "Could not receive return value from daemon process.");
1645 goto finish;
1646 }
1647
1648 r = ret;
1649 goto finish;
1650 }
1651
1652 /* Child */
1653 }
1654
1655 if (use_syslog || daemonize)
1656 daemon_log_use = DAEMON_LOG_SYSLOG;
1657
1658 chdir("/");
1659
1660 if (daemon_pid_file_create() < 0) {
1661 daemon_log(LOG_ERR, "Failed to create PID file: %s", strerror(errno));
1662
1663 if (daemonize)
1664 daemon_retval_send(1);
1665 goto finish;
1666 } else
1667 wrote_pid_file = 1;
1668
1669 avahi_set_proc_title(argv0, "%s: [%s] starting up", argv0, interface_name);
1670
1671 if (loop(ifindex, start_address) < 0)
1672 goto finish;
1673
1674 r = 0;
1675 } else if (command == DAEMON_HELP) {
1676 help(stdout, argv0);
1677
1678 r = 0;
1679 } else if (command == DAEMON_VERSION) {
1680 printf("%s "PACKAGE_VERSION"\n", argv0);
1681
1682 r = 0;
1683 } else if (command == DAEMON_KILL) {
1684 if (daemon_pid_file_kill_wait(SIGTERM, 5) < 0) {
1685 daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
1686 goto finish;
1687 }
1688
1689 r = 0;
1690 } else if (command == DAEMON_REFRESH) {
1691 if (daemon_pid_file_kill(SIGHUP) < 0) {
1692 daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
1693 goto finish;
1694 }
1695
1696 r = 0;
1697 } else if (command == DAEMON_CHECK)
1698 r = (daemon_pid_file_is_running() >= 0) ? 0 : 1;
1699
1700
1701 finish:
1702
1703 if (daemonize)
1704 daemon_retval_done();
1705
1706 if (wrote_pid_file)
1707 daemon_pid_file_remove();
1708
1709 avahi_free(log_ident);
1710 avahi_free(pid_file_name);
1711 avahi_free(argv0);
1712 avahi_free(interface_name);
1713 avahi_free(action_script);
1714
1715 return r;
1716 }
1717