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