2 This file is part of avahi.
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.
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.
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
24 #include <sys/param.h>
25 #include <sys/types.h>
27 #include <sys/ioctl.h>
28 #include <sys/socket.h>
31 #include <sys/sysctl.h>
35 #include <netpacket/packet.h>
37 #include <net/ethernet.h>
40 #include <net/if_dl.h>
41 #include <net/route.h>
43 #include <arpa/inet.h>
64 /* Old versions of PCAP defined it as D_IN */
66 #define PCAP_D_IN D_IN
71 #include <avahi-common/malloc.h>
72 #include <avahi-common/timeval.h>
73 #include <avahi-daemon/setproctitle.h>
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>
84 /* An implementation of RFC 3927 */
86 /* Constants from the RFC */
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
98 #define IPV4LL_NETWORK 0xA9FE0000L
99 #define IPV4LL_NETMASK 0xFFFF0000L
100 #define IPV4LL_HOSTMASK 0x0000FFFFL
101 #define IPV4LL_BROADCAST 0xA9FEFFFFL
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)
107 typedef enum ArpOperation {
112 typedef struct ArpPacketInfo {
113 ArpOperation operation;
115 uint32_t sender_ip_address, target_ip_address;
116 uint8_t sender_hw_address[ETHER_ADDRLEN], target_hw_address[ETHER_ADDRLEN];
119 typedef struct ArpPacket {
120 uint8_t *ether_header;
121 uint8_t *ether_payload;
124 static State state = STATE_START;
125 static int n_iteration = 0;
126 static int n_conflict = 0;
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;
139 static int no_chroot = 0;
141 static int no_drop_root = 0;
142 static int wrote_pid_file = 0;
143 static char *action_script = NULL;
152 } command = DAEMON_RUN;
154 typedef enum CalloutEvent {
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"
169 typedef struct CalloutEventInfo {
175 #define RANDOM_DEVICE "/dev/urandom"
184 static void init_rand_seed(void) {
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));
196 /* If the initialization failed by some reason, we add the time to the seed */
197 seed ^= (unsigned) time(NULL);
202 static uint32_t pick_addr(uint32_t old_addr) {
206 unsigned r = (unsigned) rand();
208 /* Reduce to 16 bits */
210 r = (r >> 16) ^ (r & 0xFFFF);
212 addr = htonl(IPV4LL_NETWORK | (uint32_t) r);
214 } while (addr == old_addr || !is_ll_address(addr));
219 static int load_address(const char *fn, uint32_t *addr) {
226 if (!(f = fopen(fn, "r"))) {
228 if (errno == ENOENT) {
233 daemon_log(LOG_ERR, "fopen() failed: %s", strerror(errno));
237 if (fscanf(f, "%u.%u.%u.%u\n", &a, &b, &c, &d) != 4) {
238 daemon_log(LOG_ERR, "Parse failure");
244 *addr = htonl((a << 24) | (b << 16) | (c << 8) | d);
254 static int save_address(const char *fn, uint32_t addr) {
262 if (!(f = fopen(fn, "w"))) {
263 daemon_log(LOG_ERR, "fopen() failed: %s", strerror(errno));
268 fprintf(f, "%s\n", inet_ntop(AF_INET, &addr, buf, sizeof (buf)));
283 * Allocate a buffer with two pointers in front, one of which is
284 * guaranteed to point ETHER_HDR_SIZE bytes into it.
286 static ArpPacket* packet_new(size_t packet_len) {
290 assert(packet_len > 0);
293 b = avahi_new0(uint8_t, sizeof(struct ArpPacket) + packet_len);
295 p->ether_header = NULL;
296 p->ether_payload = b + sizeof(struct ArpPacket);
299 b = avahi_new0(uint8_t, sizeof(struct ArpPacket) + ETHER_HDR_SIZE + packet_len);
301 p->ether_header = b + sizeof(struct ArpPacket);
302 p->ether_payload = b + sizeof(struct ArpPacket) + ETHER_HDR_SIZE;
308 static ArpPacket* packet_new_with_info(const ArpPacketInfo *info, size_t *packet_len) {
313 assert(info->operation == ARP_REQUEST || info->operation == ARP_RESPONSE);
314 assert(packet_len != NULL);
316 *packet_len = ARP_PACKET_SIZE;
317 p = packet_new(*packet_len);
318 r = p->ether_payload;
320 r[1] = 1; /* HTYPE */
321 r[2] = 8; /* PTYPE */
322 r[4] = ETHER_ADDRLEN; /* HLEN */
324 r[7] = (uint8_t) info->operation;
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);
334 static ArpPacket *packet_new_probe(uint32_t ip_address, const uint8_t*hw_address, size_t *packet_len) {
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;
342 return packet_new_with_info(&info, packet_len);
345 static ArpPacket *packet_new_announcement(uint32_t ip_address, const uint8_t* hw_address, size_t *packet_len) {
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;
354 return packet_new_with_info(&info, packet_len);
357 static int packet_parse(const ArpPacket *packet, size_t packet_len, ArpPacketInfo *info) {
361 p = (uint8_t *)packet->ether_payload;
364 if (packet_len < ARP_PACKET_SIZE)
367 /* Check HTYPE and PTYPE */
368 if (p[0] != 0 || p[1] != 1 || p[2] != 8 || p[3] != 0)
371 /* Check HLEN, PLEN, OPERATION */
372 if (p[4] != ETHER_ADDRLEN || p[5] != 4 || p[6] != 0 || (p[7] != 1 && p[7] != 2))
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);
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"
396 assert(st < STATE_MAX);
398 if (st == state && !reset_counter) {
400 DEBUG(daemon_log(LOG_DEBUG, "State iteration %s-%i", state_table[state], n_iteration));
402 DEBUG(daemon_log(LOG_DEBUG, "State transition %s-%i -> %s-0", state_table[state], n_iteration, state_table[st]));
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)));
414 avahi_set_proc_title(argv0, "%s: [%s] probing %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
417 static int interface_up(int iface) {
421 if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
422 daemon_log(LOG_ERR, "socket() failed: %s", strerror(errno));
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));
432 if (ioctl(fd, SIOCGIFFLAGS, &ifreq) < 0) {
433 daemon_log(LOG_ERR, "SIOCGIFFLAGS failed: %s", strerror(errno));
437 ifreq.ifr_flags |= IFF_UP;
439 if (ioctl(fd, SIOCSIFFLAGS, &ifreq) < 0) {
440 daemon_log(LOG_ERR, "SIOCSIFFLAGS failed: %s", strerror(errno));
457 /* Linux 'packet socket' specific implementation */
459 static int open_socket(int iface, uint8_t *hw_address) {
461 struct sockaddr_ll sa;
464 if (interface_up(iface) < 0)
467 if ((fd = socket(PF_PACKET, SOCK_DGRAM, 0)) < 0) {
468 daemon_log(LOG_ERR, "socket() failed: %s", strerror(errno));
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;
477 if (bind(fd, (struct sockaddr*) &sa, sizeof(sa)) < 0) {
478 daemon_log(LOG_ERR, "bind() failed: %s", strerror(errno));
483 if (getsockname(fd, (struct sockaddr*) &sa, &sa_len) < 0) {
484 daemon_log(LOG_ERR, "getsockname() failed: %s", strerror(errno));
488 if (sa.sll_halen != ETHER_ADDRLEN) {
489 daemon_log(LOG_ERR, "getsockname() returned invalid hardware address.");
493 memcpy(hw_address, sa.sll_addr, ETHER_ADDRLEN);
504 static int send_packet(int fd, int iface, ArpPacket *packet, size_t packet_len) {
505 struct sockaddr_ll sa;
509 assert(packet_len > 0);
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);
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));
526 static int recv_packet(int fd, ArpPacket **packet, size_t *packet_len) {
528 struct sockaddr_ll sa;
538 if (ioctl(fd, FIONREAD, &s) < 0) {
539 daemon_log(LOG_ERR, "FIONREAD failed: %s", strerror(errno));
546 *packet = packet_new(s);
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));
554 *packet_len = (size_t) r;
568 close_socket(int fd) {
572 #else /* !__linux__ */
573 /* PCAP-based implementation */
576 static char __pcap_errbuf[PCAP_ERRBUF_SIZE];
577 static uint8_t __lladdr[ETHER_ADDRLEN];
580 #define elementsof(array) (sizeof(array)/sizeof(array[0]))
584 __get_ether_addr(int ifindex, u_char *lladdr)
588 struct if_msghdr *ifm;
591 struct sockaddr_dl *sdl;
598 mib[4] = NET_RT_IFLIST;
601 if (sysctl(mib, elementsof(mib), NULL, &len, NULL, 0) != 0) {
602 daemon_log(LOG_ERR, "sysctl(NET_RT_IFLIST): %s",
609 daemon_log(LOG_ERR, "malloc(%d): %s", len, strerror(errno));
613 if (sysctl(mib, elementsof(mib), buf, &len, NULL, 0) != 0) {
614 daemon_log(LOG_ERR, "sysctl(NET_RT_IFLIST): %s",
621 for (next = buf; next < lim; next += ifm->ifm_msglen) {
622 ifm = (struct if_msghdr *)next;
623 if (ifm->ifm_type == RTM_IFINFO) {
624 sdl = (struct sockaddr_dl *)(ifm + 1);
625 memcpy(lladdr, LLADDR(sdl), ETHER_ADDRLEN);
633 #define PCAP_TIMEOUT 500 /* 0.5s */
636 open_socket(int iface, uint8_t *hw_address)
638 struct bpf_program bpf;
640 char ifname[IFNAMSIZ];
645 assert(__pp == NULL);
647 if (interface_up(iface) < 0) {
650 if (__get_ether_addr(iface, __lladdr) == -1) {
653 if (if_indextoname(iface, ifname) == NULL) {
658 * Using a timeout for BPF is fairly portable across BSDs. On most
659 * modern versions, using the timeout/nonblock/poll method results in
660 * fairly sane behavior, with the timeout only coming into play during
661 * the next_ex() call itself (so, for us, that's only when there's
662 * data). On older versions, it may result in a PCAP_TIMEOUT busy-wait
663 * on some versions, though, as the poll() may terminate at the
664 * PCAP_TIMEOUT instead of the poll() timeout.
666 pp = pcap_open_live(ifname, 1500, 0, PCAP_TIMEOUT, __pcap_errbuf);
670 err = pcap_set_datalink(pp, DLT_EN10MB);
672 daemon_log(LOG_ERR, "pcap_set_datalink: %s", pcap_geterr(pp));
676 err = pcap_setdirection(pp, PCAP_D_IN);
678 daemon_log(LOG_ERR, "pcap_setdirection: %s", pcap_geterr(pp));
683 fd = pcap_get_selectable_fd(pp);
690 * Using setnonblock is a portability stop-gap. Using the timeout in
691 * combination with setnonblock will ensure on most BSDs that the
692 * next_ex call returns in a timely fashion.
694 err = pcap_setnonblock(pp, 1, __pcap_errbuf);
700 filter = avahi_strdup_printf("arp and (ether dst ff:ff:ff:ff:ff:ff or "
701 "%02x:%02x:%02x:%02x:%02x:%02x)",
702 __lladdr[0], __lladdr[1],
703 __lladdr[2], __lladdr[3],
704 __lladdr[4], __lladdr[5]);
705 DEBUG(daemon_log(LOG_DEBUG, "Using pcap filter '%s'", filter));
707 err = pcap_compile(pp, &bpf, filter, 1, 0);
710 daemon_log(LOG_ERR, "pcap_compile: %s", pcap_geterr(pp));
714 err = pcap_setfilter(pp, &bpf);
716 daemon_log(LOG_ERR, "pcap_setfilter: %s", pcap_geterr(pp));
722 /* Stash pcap-specific context away. */
723 memcpy(hw_address, __lladdr, ETHER_ADDRLEN);
730 close_socket(int fd __unused)
733 assert(__pp != NULL);
739 * We trick avahi into allocating sizeof(packet) + sizeof(ether_header),
740 * and prepend the required ethernet header information before sending.
743 send_packet(int fd __unused, int iface __unused, ArpPacket *packet,
746 struct ether_header *eh;
748 assert(__pp != NULL);
749 assert(packet != NULL);
751 eh = (struct ether_header *)packet->ether_header;
752 memset(eh->ether_dhost, 0xFF, ETHER_ADDRLEN);
753 memcpy(eh->ether_shost, __lladdr, ETHER_ADDRLEN);
754 eh->ether_type = htons(0x0806);
756 return (pcap_inject(__pp, (void *)eh, packet_len + sizeof(*eh)));
760 recv_packet(int fd __unused, ArpPacket **packet, size_t *packet_len)
762 struct pcap_pkthdr *ph;
768 assert(__pp != NULL);
769 assert(packet != NULL);
770 assert(packet_len != NULL);
776 err = pcap_next_ex(__pp, &ph, (const u_char **)&pd);
777 if (err == 1 && ph->caplen <= ph->len) {
778 ap = packet_new(ph->caplen);
779 memcpy(ap->ether_header, pd, ph->caplen);
781 *packet_len = (ph->caplen - sizeof(struct ether_header));
783 } else if (err >= 0) {
785 * err == 1: Just drop bogus packets (>1500 for an arp packet!?)
788 * err == 0: We might have had traffic on the pcap fd that
789 * didn't match the filter, in which case we'll get 0 packets.
793 daemon_log(LOG_ERR, "pcap_next_ex(%d): %s",
794 err, pcap_geterr(__pp));
799 #endif /* __linux__ */
801 int is_ll_address(uint32_t addr) {
803 ((ntohl(addr) & IPV4LL_NETMASK) == IPV4LL_NETWORK) &&
804 ((ntohl(addr) & 0x0000FF00) != 0x0000) &&
805 ((ntohl(addr) & 0x0000FF00) != 0xFF00);
808 static struct timeval *elapse_time(struct timeval *tv, unsigned msec, unsigned jitter) {
811 gettimeofday(tv, NULL);
814 avahi_timeval_add(tv, (AvahiUsec) msec*1000);
817 avahi_timeval_add(tv, (AvahiUsec) (jitter*1000.0*rand()/(RAND_MAX+1.0)));
822 static FILE* fork_dispatcher(void) {
828 daemon_log(LOG_ERR, "pipe() failed: %s", strerror(errno));
832 if ((pid = fork()) < 0)
838 /* Please note that the signal pipe is not closed at this
839 * point, signals will thus be dispatched in the main
842 daemon_retval_done();
846 avahi_set_proc_title(argv0, "%s: [%s] callout dispatcher", argv0, interface_name);
850 if (!(f = fdopen(fds[0], "r"))) {
851 daemon_log(LOG_ERR, "fdopen() failed: %s", strerror(errno));
852 goto dispatcher_fail;
856 CalloutEventInfo info;
857 char name[IFNAMSIZ], buf[64];
860 if (fread(&info, sizeof(info), 1, f) != 1) {
864 daemon_log(LOG_ERR, "fread() failed: %s", strerror(errno));
865 goto dispatcher_fail;
868 assert(info.event <= CALLOUT_MAX);
870 if (!if_indextoname(info.ifindex, name)) {
871 daemon_log(LOG_ERR, "if_indextoname() failed: %s", strerror(errno));
875 if (daemon_exec("/", &k,
876 action_script, action_script,
877 callout_event_table[info.event],
879 inet_ntop(AF_INET, &info.address, buf, sizeof(buf)), NULL) < 0) {
881 daemon_log(LOG_ERR, "Failed to run script: %s", strerror(errno));
886 daemon_log(LOG_WARNING, "Script execution failed with return value %i", k);
897 /* If the main process is trapped inside a chroot() we have to
898 * remove the PID file for it */
900 if (!no_chroot && wrote_pid_file)
901 daemon_pid_file_remove();
912 if (!(ret = fdopen(fds[1], "w"))) {
913 daemon_log(LOG_ERR, "fdopen() failed: %s", strerror(errno));
928 static int do_callout(FILE *f, CalloutEvent event, int iface, uint32_t addr) {
929 CalloutEventInfo info;
930 char buf[64], ifname[IFNAMSIZ];
932 daemon_log(LOG_INFO, "Callout %s, address %s on interface %s",
933 callout_event_table[event],
934 inet_ntop(AF_INET, &addr, buf, sizeof(buf)),
935 if_indextoname(iface, ifname));
938 info.ifindex = iface;
941 if (fwrite(&info, sizeof(info), 1, f) != 1 || fflush(f) != 0) {
942 daemon_log(LOG_ERR, "Failed to write callout event: %s", strerror(errno));
949 #define set_env(key, value) putenv(avahi_strdup_printf("%s=%s", (key), (value)))
951 static int drop_privs(void) {
960 /* Get user/group ID */
964 if (!(pw = getpwnam(AVAHI_AUTOIPD_USER))) {
965 daemon_log(LOG_ERR, "Failed to find user '"AVAHI_AUTOIPD_USER"'.");
969 if (!(gr = getgrnam(AVAHI_AUTOIPD_GROUP))) {
970 daemon_log(LOG_ERR, "Failed to find group '"AVAHI_AUTOIPD_GROUP"'.");
974 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);
977 /* Create directory */
979 r = mkdir(AVAHI_IPDATA_DIR, 0755);
982 if (r < 0 && errno != EEXIST) {
983 daemon_log(LOG_ERR, "mkdir(\""AVAHI_IPDATA_DIR"\"): %s", strerror(errno));
987 /* Convey working directory */
992 chown(AVAHI_IPDATA_DIR, pw->pw_uid, gr->gr_gid);
994 if (stat(AVAHI_IPDATA_DIR, &st) < 0) {
995 daemon_log(LOG_ERR, "stat(): %s\n", strerror(errno));
999 if (!S_ISDIR(st.st_mode) || st.st_uid != pw->pw_uid || st.st_gid != gr->gr_gid) {
1000 daemon_log(LOG_ERR, "Failed to create runtime directory "AVAHI_IPDATA_DIR".");
1008 if (chroot(AVAHI_IPDATA_DIR) < 0) {
1009 daemon_log(LOG_ERR, "Failed to chroot(): %s", strerror(errno));
1013 daemon_log(LOG_INFO, "Successfully called chroot().");
1016 /* Since we are now trapped inside a chroot we cannot remove
1017 * the pid file anymore, the helper process will do that for us. */
1023 if (!no_drop_root) {
1025 if (initgroups(AVAHI_AUTOIPD_USER, gr->gr_gid) != 0) {
1026 daemon_log(LOG_ERR, "Failed to change group list: %s", strerror(errno));
1030 #if defined(HAVE_SETRESGID)
1031 r = setresgid(gr->gr_gid, gr->gr_gid, gr->gr_gid);
1032 #elif defined(HAVE_SETEGID)
1033 if ((r = setgid(gr->gr_gid)) >= 0)
1034 r = setegid(gr->gr_gid);
1035 #elif defined(HAVE_SETREGID)
1036 r = setregid(gr->gr_gid, gr->gr_gid);
1038 #error "No API to drop privileges"
1042 daemon_log(LOG_ERR, "Failed to change GID: %s", strerror(errno));
1046 #if defined(HAVE_SETRESUID)
1047 r = setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid);
1048 #elif defined(HAVE_SETEUID)
1049 if ((r = setuid(pw->pw_uid)) >= 0)
1050 r = seteuid(pw->pw_uid);
1051 #elif defined(HAVE_SETREUID)
1052 r = setreuid(pw->pw_uid, pw->pw_uid);
1054 #error "No API to drop privileges"
1058 daemon_log(LOG_ERR, "Failed to change UID: %s", strerror(errno));
1062 set_env("USER", pw->pw_name);
1063 set_env("LOGNAME", pw->pw_name);
1064 set_env("HOME", pw->pw_dir);
1066 daemon_log(LOG_INFO, "Successfully dropped root privileges.");
1072 static int loop(int iface, uint32_t addr) {
1080 int fd = -1, ret = -1;
1081 struct timeval next_wakeup;
1082 int next_wakeup_valid = 0;
1084 ArpPacket *in_packet = NULL;
1085 size_t in_packet_len;
1086 ArpPacket *out_packet = NULL;
1087 size_t out_packet_len;
1088 uint8_t hw_address[ETHER_ADDRLEN];
1089 struct pollfd pollfds[FD_MAX];
1091 Event event = EVENT_NULL;
1092 int retval_sent = !daemonize;
1094 FILE *dispatcher = NULL;
1095 char *address_fn = NULL;
1098 daemon_signal_init(SIGINT, SIGTERM, SIGCHLD, SIGHUP,0);
1100 if (!(dispatcher = fork_dispatcher()))
1103 if ((fd = open_socket(iface, hw_address)) < 0)
1106 if ((iface_fd = iface_init(iface)) < 0)
1109 if (drop_privs() < 0)
1114 else if (iface_get_initial_state(&st) < 0)
1122 p = AVAHI_IPDATA_DIR;
1124 address_fn = avahi_strdup_printf(
1125 "%s/%02x:%02x:%02x:%02x:%02x:%02x", p,
1126 hw_address[0], hw_address[1],
1127 hw_address[2], hw_address[3],
1128 hw_address[4], hw_address[5]);
1131 load_address(address_fn, &addr);
1133 if (addr && !is_ll_address(addr)) {
1134 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)));
1142 for (i = 0; i < ETHER_ADDRLEN; i++)
1143 a += hw_address[i]*i;
1145 a = (a % 0xFE00) + 0x0100;
1147 addr = htonl(IPV4LL_NETWORK | (uint32_t) a);
1150 assert(is_ll_address(addr));
1152 set_state(st, 1, addr);
1154 daemon_log(LOG_INFO, "Starting with address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
1156 if (state == STATE_SLEEPING)
1157 daemon_log(LOG_INFO, "Routable address already assigned, sleeping.");
1159 if (!retval_sent && (!wait_for_address || state == STATE_SLEEPING)) {
1160 daemon_retval_send(0);
1164 memset(pollfds, 0, sizeof(pollfds));
1165 pollfds[FD_ARP].fd = fd;
1166 pollfds[FD_ARP].events = POLLIN;
1167 pollfds[FD_IFACE].fd = iface_fd;
1168 pollfds[FD_IFACE].events = POLLIN;
1169 pollfds[FD_SIGNAL].fd = daemon_signal_fd();
1170 pollfds[FD_SIGNAL].events = POLLIN;
1176 if (state == STATE_START) {
1178 /* First, wait a random time */
1179 set_state(STATE_WAITING_PROBE, 1, addr);
1181 elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
1182 next_wakeup_valid = 1;
1184 } else if ((state == STATE_WAITING_PROBE && event == EVENT_TIMEOUT) ||
1185 (state == STATE_PROBING && event == EVENT_TIMEOUT && n_iteration < PROBE_NUM-2)) {
1188 out_packet = packet_new_probe(addr, hw_address, &out_packet_len);
1189 set_state(STATE_PROBING, 0, addr);
1191 elapse_time(&next_wakeup, PROBE_MIN*1000, (PROBE_MAX-PROBE_MIN)*1000);
1192 next_wakeup_valid = 1;
1194 } else if (state == STATE_PROBING && event == EVENT_TIMEOUT && n_iteration >= PROBE_NUM-2) {
1196 /* Send the last probe */
1197 out_packet = packet_new_probe(addr, hw_address, &out_packet_len);
1198 set_state(STATE_WAITING_ANNOUNCE, 1, addr);
1200 elapse_time(&next_wakeup, ANNOUNCE_WAIT*1000, 0);
1201 next_wakeup_valid = 1;
1203 } else if ((state == STATE_WAITING_ANNOUNCE && event == EVENT_TIMEOUT) ||
1204 (state == STATE_ANNOUNCING && event == EVENT_TIMEOUT && n_iteration < ANNOUNCE_NUM-1)) {
1206 /* Send announcement packet */
1207 out_packet = packet_new_announcement(addr, hw_address, &out_packet_len);
1208 set_state(STATE_ANNOUNCING, 0, addr);
1210 elapse_time(&next_wakeup, ANNOUNCE_INTERVAL*1000, 0);
1211 next_wakeup_valid = 1;
1213 if (n_iteration == 0) {
1214 if (do_callout(dispatcher, CALLOUT_BIND, iface, addr) < 0)
1220 } else if ((state == STATE_ANNOUNCING && event == EVENT_TIMEOUT && n_iteration >= ANNOUNCE_NUM-1)) {
1222 daemon_log(LOG_INFO, "Successfully claimed IP address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
1223 set_state(STATE_RUNNING, 0, addr);
1225 next_wakeup_valid = 0;
1227 save_address(address_fn, addr);
1230 daemon_retval_send(0);
1234 } else if (event == EVENT_PACKET) {
1239 if (packet_parse(in_packet, in_packet_len, &info) < 0)
1240 daemon_log(LOG_WARNING, "Failed to parse incoming ARP packet.");
1244 if (info.sender_ip_address == addr) {
1245 /* Normal conflict */
1247 daemon_log(LOG_INFO, "Received conflicting normal ARP packet.");
1248 } else if (state == STATE_WAITING_PROBE || state == STATE_PROBING || state == STATE_WAITING_ANNOUNCE) {
1249 /* Probe conflict */
1250 conflict = info.target_ip_address == addr && memcmp(hw_address, info.sender_hw_address, ETHER_ADDRLEN);
1253 daemon_log(LOG_INFO, "Received conflicting probe ARP packet.");
1258 if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
1259 if (do_callout(dispatcher, CALLOUT_CONFLICT, iface, addr) < 0)
1262 /* Pick a new address */
1263 addr = pick_addr(addr);
1265 daemon_log(LOG_INFO, "Trying address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
1269 set_state(STATE_WAITING_PROBE, 1, addr);
1271 if (n_conflict >= MAX_CONFLICTS) {
1272 daemon_log(LOG_WARNING, "Got too many conflicts, rate limiting new probes.");
1273 elapse_time(&next_wakeup, RATE_LIMIT_INTERVAL*1000, PROBE_WAIT*1000);
1275 elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
1277 next_wakeup_valid = 1;
1279 DEBUG(daemon_log(LOG_DEBUG, "Ignoring irrelevant ARP packet."));
1282 } else if (event == EVENT_ROUTABLE_ADDR_CONFIGURED && !force_bind) {
1284 daemon_log(LOG_INFO, "A routable address has been configured.");
1286 if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
1287 if (do_callout(dispatcher, CALLOUT_UNBIND, iface, addr) < 0)
1291 daemon_retval_send(0);
1295 set_state(STATE_SLEEPING, 1, addr);
1296 next_wakeup_valid = 0;
1298 } else if (event == EVENT_ROUTABLE_ADDR_UNCONFIGURED && state == STATE_SLEEPING && !force_bind) {
1300 daemon_log(LOG_INFO, "No longer a routable address configured, restarting probe process.");
1302 set_state(STATE_WAITING_PROBE, 1, addr);
1304 elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
1305 next_wakeup_valid = 1;
1307 } else if (event == EVENT_REFRESH_REQUEST && state == STATE_RUNNING) {
1309 /* The user requested a reannouncing of the address by a SIGHUP */
1310 daemon_log(LOG_INFO, "Reannouncing address.");
1312 /* Send announcement packet */
1313 out_packet = packet_new_announcement(addr, hw_address, &out_packet_len);
1314 set_state(STATE_ANNOUNCING, 1, addr);
1316 elapse_time(&next_wakeup, ANNOUNCE_INTERVAL*1000, 0);
1317 next_wakeup_valid = 1;
1321 DEBUG(daemon_log(LOG_DEBUG, "sending..."));
1323 if (send_packet(fd, iface, out_packet, out_packet_len) < 0)
1326 avahi_free(out_packet);
1331 avahi_free(in_packet);
1338 if (next_wakeup_valid) {
1339 usec = avahi_age(&next_wakeup);
1340 timeout = usec < 0 ? (int) (-usec/1000) : 0;
1343 DEBUG(daemon_log(LOG_DEBUG, "sleeping %ims", timeout));
1345 while ((r = poll(pollfds, FD_MAX, timeout)) < 0 && errno == EINTR)
1349 daemon_log(LOG_ERR, "poll() failed: %s", strerror(r));
1351 } else if (r == 0) {
1352 event = EVENT_TIMEOUT;
1353 next_wakeup_valid = 0;
1357 if (pollfds[FD_ARP].revents) {
1359 if (pollfds[FD_ARP].revents == POLLERR) {
1360 /* The interface is probably down, let's recreate our socket */
1364 if ((fd = open_socket(iface, hw_address)) < 0)
1367 pollfds[FD_ARP].fd = fd;
1371 assert(pollfds[FD_ARP].revents == POLLIN);
1373 if (recv_packet(fd, &in_packet, &in_packet_len) < 0)
1377 event = EVENT_PACKET;
1381 if (event == EVENT_NULL &&
1382 pollfds[FD_IFACE].revents) {
1384 assert(pollfds[FD_IFACE].revents == POLLIN);
1386 if (iface_process(&event) < 0)
1390 if (event == EVENT_NULL &&
1391 pollfds[FD_SIGNAL].revents) {
1394 assert(pollfds[FD_SIGNAL].revents == POLLIN);
1396 if ((sig = daemon_signal_next()) <= 0) {
1397 daemon_log(LOG_ERR, "daemon_signal_next() failed");
1404 daemon_log(LOG_INFO, "Got %s, quitting.", sig == SIGINT ? "SIGINT" : "SIGTERM");
1409 waitpid(-1, NULL, WNOHANG);
1413 event = EVENT_REFRESH_REQUEST;
1425 if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
1426 do_callout(dispatcher, CALLOUT_STOP, iface, addr);
1428 avahi_free(out_packet);
1429 avahi_free(in_packet);
1437 if (daemonize && !retval_sent)
1438 daemon_retval_send(ret);
1444 avahi_free(address_fn);
1450 static void help(FILE *f, const char *a0) {
1452 "%s [options] INTERFACE\n"
1453 " -h --help Show this help\n"
1454 " -D --daemonize Daemonize after startup\n"
1455 " -s --syslog Write log messages to syslog(3) instead of STDERR\n"
1456 " -k --kill Kill a running daemon\n"
1457 " -r --refresh Request a running daemon refresh its IP address\n"
1458 " -c --check Return 0 if a daemon is already running\n"
1459 " -V --version Show version\n"
1460 " -S --start=ADDRESS Start with this address from the IPv4LL range\n"
1462 " -t --script=script Action script to run (defaults to\n"
1463 " "AVAHI_IPCONF_SCRIPT")\n"
1464 " -w --wait Wait until an address has been acquired before\n"
1466 " --force-bind Assign an IPv4LL address even if a routable address\n"
1467 " is already assigned\n"
1468 " --no-drop-root Don't drop privileges\n"
1470 " --no-chroot Don't chroot()\n"
1472 " --no-proc-title Don't modify process title\n"
1473 " --debug Increase verbosity\n",
1477 static int parse_command_line(int argc, char *argv[]) {
1481 OPTION_NO_PROC_TITLE = 256,
1484 OPTION_NO_DROP_ROOT,
1490 static const struct option long_options[] = {
1491 { "help", no_argument, NULL, 'h' },
1492 { "daemonize", no_argument, NULL, 'D' },
1493 { "syslog", no_argument, NULL, 's' },
1494 { "kill", no_argument, NULL, 'k' },
1495 { "refresh", no_argument, NULL, 'r' },
1496 { "check", no_argument, NULL, 'c' },
1497 { "version", no_argument, NULL, 'V' },
1498 { "start", required_argument, NULL, 'S' },
1499 { "script", required_argument, NULL, 't' },
1500 { "wait", no_argument, NULL, 'w' },
1501 { "force-bind", no_argument, NULL, OPTION_FORCE_BIND },
1502 { "no-drop-root", no_argument, NULL, OPTION_NO_DROP_ROOT },
1504 { "no-chroot", no_argument, NULL, OPTION_NO_CHROOT },
1506 { "no-proc-title", no_argument, NULL, OPTION_NO_PROC_TITLE },
1507 { "debug", no_argument, NULL, OPTION_DEBUG },
1508 { NULL, 0, NULL, 0 }
1511 while ((c = getopt_long(argc, argv, "hDskrcVS:t:w", long_options, NULL)) >= 0) {
1518 command = DAEMON_HELP;
1524 command = DAEMON_KILL;
1527 command = DAEMON_VERSION;
1530 command = DAEMON_REFRESH;
1533 command = DAEMON_CHECK;
1537 if ((start_address = inet_addr(optarg)) == (uint32_t) -1) {
1538 fprintf(stderr, "Failed to parse IP address '%s'.", optarg);
1543 avahi_free(action_script);
1544 action_script = avahi_strdup(optarg);
1547 wait_for_address = 1;
1550 case OPTION_NO_PROC_TITLE:
1551 modify_proc_title = 0;
1558 case OPTION_FORCE_BIND:
1562 case OPTION_NO_DROP_ROOT:
1567 case OPTION_NO_CHROOT:
1577 if (command == DAEMON_RUN ||
1578 command == DAEMON_KILL ||
1579 command == DAEMON_REFRESH ||
1580 command == DAEMON_CHECK) {
1582 if (optind >= argc) {
1583 fprintf(stderr, "Missing interface name.\n");
1587 interface_name = avahi_strdup(argv[optind++]);
1590 if (optind != argc) {
1591 fprintf(stderr, "Too many arguments\n");
1596 action_script = avahi_strdup(AVAHI_IPCONF_SCRIPT);
1601 static const char* pid_file_proc(void) {
1602 return pid_file_name;
1605 int main(int argc, char*argv[]) {
1607 char *log_ident = NULL;
1609 signal(SIGPIPE, SIG_IGN);
1611 if ((argv0 = strrchr(argv[0], '/')))
1612 argv0 = avahi_strdup(argv0 + 1);
1614 argv0 = avahi_strdup(argv[0]);
1616 daemon_log_ident = argv0;
1618 if (parse_command_line(argc, argv) < 0)
1621 if (modify_proc_title)
1622 avahi_init_proc_title(argc, argv);
1624 daemon_log_ident = log_ident = avahi_strdup_printf("%s(%s)", argv0, interface_name);
1625 daemon_pid_file_proc = pid_file_proc;
1626 pid_file_name = avahi_strdup_printf(AVAHI_RUNTIME_DIR"/avahi-autoipd.%s.pid", interface_name);
1628 if (command == DAEMON_RUN) {
1634 if ((ifindex = if_nametoindex(interface_name)) <= 0) {
1635 daemon_log(LOG_ERR, "Failed to get index for interface name '%s': %s", interface_name, strerror(errno));
1639 if (getuid() != 0) {
1640 daemon_log(LOG_ERR, "This program is intended to be run as root.");
1644 if ((pid = daemon_pid_file_is_running()) >= 0) {
1645 daemon_log(LOG_ERR, "Daemon already running on PID %u", pid);
1650 daemon_retval_init();
1652 if ((pid = daemon_fork()) < 0)
1654 else if (pid != 0) {
1658 if ((ret = daemon_retval_wait(20)) < 0) {
1659 daemon_log(LOG_ERR, "Could not receive return value from daemon process.");
1670 if (use_syslog || daemonize)
1671 daemon_log_use = DAEMON_LOG_SYSLOG;
1675 if (daemon_pid_file_create() < 0) {
1676 daemon_log(LOG_ERR, "Failed to create PID file: %s", strerror(errno));
1679 daemon_retval_send(1);
1684 avahi_set_proc_title(argv0, "%s: [%s] starting up", argv0, interface_name);
1686 if (loop(ifindex, start_address) < 0)
1690 } else if (command == DAEMON_HELP) {
1691 help(stdout, argv0);
1694 } else if (command == DAEMON_VERSION) {
1695 printf("%s "PACKAGE_VERSION"\n", argv0);
1698 } else if (command == DAEMON_KILL) {
1699 if (daemon_pid_file_kill_wait(SIGTERM, 5) < 0) {
1700 daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
1705 } else if (command == DAEMON_REFRESH) {
1706 if (daemon_pid_file_kill(SIGHUP) < 0) {
1707 daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
1712 } else if (command == DAEMON_CHECK)
1713 r = (daemon_pid_file_is_running() >= 0) ? 0 : 1;
1719 daemon_retval_done();
1722 daemon_pid_file_remove();
1724 avahi_free(log_ident);
1725 avahi_free(pid_file_name);
1727 avahi_free(interface_name);
1728 avahi_free(action_script);