main.c revision 287f9866c923e6afe8ffbbc03b90be64acf395e1 
1/* $Id$ */
2
3/***
4  This file is part of avahi.
5
6  avahi is free software; you can redistribute it and/or modify it
7  under the terms of the GNU Lesser General Public License as
8  published by the Free Software Foundation; either version 2.1 of the
9  License, or (at your option) any later version.
10
11  avahi is distributed in the hope that it will be useful, but WITHOUT
12  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
14  Public License for more details.
15
16  You should have received a copy of the GNU Lesser General Public
17  License along with avahi; if not, write to the Free Software
18  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
19  USA.
20***/
21
22#ifdef HAVE_CONFIG_H
23#include <config.h>
24#endif
25
26#include <stdlib.h>
27#include <unistd.h>
28#include <sys/socket.h>
29#include <netpacket/packet.h>
30#include <net/ethernet.h>
31#include <fcntl.h>
32#include <time.h>
33#include <assert.h>
34#include <errno.h>
35#include <string.h>
36#include <inttypes.h>
37#include <sys/types.h>
38#include <arpa/inet.h>
39#include <sys/ioctl.h>
40#include <poll.h>
41#include <net/if.h>
42#include <stdio.h>
43#include <getopt.h>
44#include <signal.h>
45#include <sys/wait.h>
46
47#include <avahi-common/malloc.h>
48#include <avahi-common/timeval.h>
49
50#include <avahi-daemon/setproctitle.h>
51
52#include <libdaemon/dfork.h>
53#include <libdaemon/dsignal.h>
54#include <libdaemon/dlog.h>
55#include <libdaemon/dpid.h>
56#include <libdaemon/dexec.h>
57
58#include "main.h"
59#include "iface.h"
60
61#ifndef __linux__
62#error "avahi-autoipd is only available on Linux for now"
63#endif
64
65/* An implementation of RFC 3927 */
66
67/* Constants from the RFC */
68#define PROBE_WAIT 1
69#define PROBE_NUM 3
70#define PROBE_MIN 1
71#define PROBE_MAX 2
72#define ANNOUNCE_WAIT 2
73#define ANNOUNCE_NUM 2
74#define ANNOUNCE_INTERVAL 2
75#define MAX_CONFLICTS 10
76#define RATE_LIMIT_INTERVAL 60
77#define DEFEND_INTERVAL 10
78
79#define IPV4LL_NETWORK 0xA9FE0000L
80#define IPV4LL_NETMASK 0xFFFF0000L
81#define IPV4LL_HOSTMASK 0x0000FFFFL
82
83#define ETHER_ADDRLEN 6
84#define ARP_PACKET_SIZE (8+4+4+2*ETHER_ADDRLEN)
85
86typedef enum ArpOperation {
87    ARP_REQUEST = 1,
88    ARP_RESPONSE = 2
89} ArpOperation;
90
91typedef struct ArpPacketInfo {
92    ArpOperation operation;
93
94    uint32_t sender_ip_address, target_ip_address;
95    uint8_t sender_hw_address[ETHER_ADDRLEN], target_hw_address[ETHER_ADDRLEN];
96} ArpPacketInfo;
97
98static State state = STATE_START;
99static int n_iteration = 0;
100static int n_conflict = 0;
101
102static char *interface_name = NULL;
103static char *pid_file_name = NULL;
104static uint32_t start_address = 0;
105static char *argv0 = NULL;
106static int daemonize = 0;
107static int wait_for_address = 0;
108static int use_syslog = 0;
109static int debug = 0;
110static int modify_proc_title = 1;
111static int force_bind = 0;
112
113static enum {
114    DAEMON_RUN,
115    DAEMON_KILL,
116    DAEMON_REFRESH,
117    DAEMON_VERSION,
118    DAEMON_HELP,
119    DAEMON_CHECK
120} command = DAEMON_RUN;
121
122typedef enum CalloutEvent {
123    CALLOUT_BIND,
124    CALLOUT_CONFLICT,
125    CALLOUT_UNBIND,
126    CALLOUT_STOP,
127    CALLOUT_MAX
128} CalloutEvent;
129
130static const char * const callout_event_table[CALLOUT_MAX] = {
131    [CALLOUT_BIND] = "BIND",
132    [CALLOUT_CONFLICT] = "CONFLICT",
133    [CALLOUT_UNBIND] = "UNBIND",
134    [CALLOUT_STOP] = "STOP"
135};
136
137typedef struct CalloutEventInfo {
138    CalloutEvent event;
139    uint32_t address;
140    int ifindex;
141} CalloutEventInfo;
142
143#define RANDOM_DEVICE "/dev/urandom"
144
145#define DEBUG(x) do {\
146if (debug) { \
147    x; \
148} \
149} while (0)
150
151static void init_rand_seed(void) {
152    int fd;
153    unsigned seed = 0;
154
155    /* Try to initialize seed from /dev/urandom, to make it a little
156     * less predictable, and to make sure that multiple machines
157     * booted at the same time choose different random seeds.  */
158    if ((fd = open(RANDOM_DEVICE, O_RDONLY)) >= 0) {
159        read(fd, &seed, sizeof(seed));
160        close(fd);
161    }
162
163    /* If the initialization failed by some reason, we add the time to the seed */
164    seed ^= (unsigned) time(NULL);
165
166    srand(seed);
167}
168
169static uint32_t pick_addr(uint32_t old_addr) {
170    uint32_t addr;
171
172    do {
173        unsigned r = (unsigned) rand();
174
175        /* Reduce to 16 bits */
176        while (r > 0xFFFF)
177            r = (r >> 16) ^ (r & 0xFFFF);
178
179        addr = htonl(IPV4LL_NETWORK | (uint32_t) r);
180
181    } while (addr == old_addr);
182
183    return addr;
184}
185
186static void* packet_new(const ArpPacketInfo *info, size_t *packet_len) {
187    uint8_t *r;
188
189    assert(info);
190    assert(packet_len);
191    assert(info->operation == ARP_REQUEST || info->operation == ARP_RESPONSE);
192
193    *packet_len = ARP_PACKET_SIZE;
194    r = avahi_new0(uint8_t, *packet_len);
195
196    r[1] = 1; /* HTYPE */
197    r[2] = 8; /* PTYPE */
198    r[4] = ETHER_ADDRLEN; /* HLEN */
199    r[5] = 4; /* PLEN */
200    r[7] = (uint8_t) info->operation;
201
202    memcpy(r+8, info->sender_hw_address, ETHER_ADDRLEN);
203    memcpy(r+14, &info->sender_ip_address, 4);
204    memcpy(r+18, info->target_hw_address, ETHER_ADDRLEN);
205    memcpy(r+24, &info->target_ip_address, 4);
206
207    return r;
208}
209
210static void *packet_new_probe(uint32_t ip_address, const uint8_t*hw_address, size_t *packet_len) {
211    ArpPacketInfo info;
212
213    memset(&info, 0, sizeof(info));
214    info.operation = ARP_REQUEST;
215    memcpy(info.sender_hw_address, hw_address, ETHER_ADDRLEN);
216    info.target_ip_address = ip_address;
217
218    return packet_new(&info, packet_len);
219}
220
221static void *packet_new_announcement(uint32_t ip_address, const uint8_t* hw_address, size_t *packet_len) {
222    ArpPacketInfo info;
223
224    memset(&info, 0, sizeof(info));
225    info.operation = ARP_REQUEST;
226    memcpy(info.sender_hw_address, hw_address, ETHER_ADDRLEN);
227    info.target_ip_address = ip_address;
228    info.sender_ip_address = ip_address;
229
230    return packet_new(&info, packet_len);
231}
232
233static int packet_parse(const void *data, size_t packet_len, ArpPacketInfo *info) {
234    const uint8_t *p = data;
235
236    assert(data);
237
238    if (packet_len < ARP_PACKET_SIZE)
239        return -1;
240
241    /* Check HTYPE and PTYPE */
242    if (p[0] != 0 || p[1] != 1 || p[2] != 8 || p[3] != 0)
243        return -1;
244
245    /* Check HLEN, PLEN, OPERATION */
246    if (p[4] != ETHER_ADDRLEN || p[5] != 4 || p[6] != 0 || (p[7] != 1 && p[7] != 2))
247        return -1;
248
249    info->operation = p[7];
250    memcpy(info->sender_hw_address, p+8, ETHER_ADDRLEN);
251    memcpy(&info->sender_ip_address, p+14, 4);
252    memcpy(info->target_hw_address, p+18, ETHER_ADDRLEN);
253    memcpy(&info->target_ip_address, p+24, 4);
254
255    return 0;
256}
257
258static void set_state(State st, int reset_counter, uint32_t address) {
259    static const char* const state_table[] = {
260        [STATE_START] = "START",
261        [STATE_WAITING_PROBE] = "WAITING_PROBE",
262        [STATE_PROBING] = "PROBING",
263        [STATE_WAITING_ANNOUNCE] = "WAITING_ANNOUNCE",
264        [STATE_ANNOUNCING] = "ANNOUNCING",
265        [STATE_RUNNING] = "RUNNING",
266        [STATE_SLEEPING] = "SLEEPING"
267    };
268    char buf[64];
269
270    assert(st < STATE_MAX);
271
272    if (st == state && !reset_counter) {
273        n_iteration++;
274        DEBUG(daemon_log(LOG_DEBUG, "State iteration %s-%i", state_table[state], n_iteration));
275    } else {
276        DEBUG(daemon_log(LOG_DEBUG, "State transition %s-%i -> %s-0", state_table[state], n_iteration, state_table[st]));
277        state = st;
278        n_iteration = 0;
279    }
280
281    if (modify_proc_title) {
282        if (state == STATE_SLEEPING)
283            avahi_set_proc_title(argv0, "%s: [%s] sleeping", argv0, interface_name);
284        else if (state == STATE_ANNOUNCING)
285            avahi_set_proc_title(argv0, "%s: [%s] announcing %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
286        else if (state == STATE_RUNNING)
287            avahi_set_proc_title(argv0, "%s: [%s] bound %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
288        else
289            avahi_set_proc_title(argv0, "%s: [%s] probing %s", argv0, interface_name, inet_ntop(AF_INET, &address, buf, sizeof(buf)));
290    }
291}
292
293static int interface_up(int iface) {
294    int fd = -1;
295    struct ifreq ifreq;
296
297    if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
298        daemon_log(LOG_ERR, "socket() failed: %s", strerror(errno));
299        goto fail;
300    }
301
302    memset(&ifreq, 0, sizeof(ifreq));
303    if (!if_indextoname(iface, ifreq.ifr_name)) {
304        daemon_log(LOG_ERR, "if_indextoname() failed: %s", strerror(errno));
305        goto fail;
306    }
307
308    if (ioctl(fd, SIOCGIFFLAGS, &ifreq) < 0) {
309        daemon_log(LOG_ERR, "SIOCGIFFLAGS failed: %s", strerror(errno));
310        goto fail;
311    }
312
313    ifreq.ifr_flags |= IFF_UP;
314
315    if (ioctl(fd, SIOCSIFFLAGS, &ifreq) < 0) {
316        daemon_log(LOG_ERR, "SIOCSIFFLAGS failed: %s", strerror(errno));
317        goto fail;
318    }
319
320    close(fd);
321
322    return 0;
323
324fail:
325    if (fd >= 0)
326        close(fd);
327
328    return -1;
329}
330
331static int open_socket(int iface, uint8_t *hw_address) {
332    int fd = -1;
333    struct sockaddr_ll sa;
334    socklen_t sa_len;
335
336    if (interface_up(iface) < 0)
337        goto fail;
338
339    if ((fd = socket(PF_PACKET, SOCK_DGRAM, 0)) < 0) {
340        daemon_log(LOG_ERR, "socket() failed: %s", strerror(errno));
341        goto fail;
342    }
343
344    memset(&sa, 0, sizeof(sa));
345    sa.sll_family = AF_PACKET;
346    sa.sll_protocol = htons(ETH_P_ARP);
347    sa.sll_ifindex = iface;
348
349    if (bind(fd, (struct sockaddr*) &sa, sizeof(sa)) < 0) {
350        daemon_log(LOG_ERR, "bind() failed: %s", strerror(errno));
351        goto fail;
352    }
353
354    sa_len = sizeof(sa);
355    if (getsockname(fd, (struct sockaddr*) &sa, &sa_len) < 0) {
356        daemon_log(LOG_ERR, "getsockname() failed: %s", strerror(errno));
357        goto fail;
358    }
359
360    if (sa.sll_halen != ETHER_ADDRLEN) {
361        daemon_log(LOG_ERR, "getsockname() returned invalid hardware address.");
362        goto fail;
363    }
364
365    memcpy(hw_address, sa.sll_addr, ETHER_ADDRLEN);
366
367    return fd;
368
369fail:
370    if (fd >= 0)
371        close(fd);
372
373    return -1;
374}
375
376static int send_packet(int fd, int iface, void *packet, size_t packet_len) {
377    struct sockaddr_ll sa;
378
379    assert(fd >= 0);
380    assert(packet);
381    assert(packet_len > 0);
382
383    memset(&sa, 0, sizeof(sa));
384    sa.sll_family = AF_PACKET;
385    sa.sll_protocol = htons(ETH_P_ARP);
386    sa.sll_ifindex = iface;
387    sa.sll_halen = ETHER_ADDRLEN;
388    memset(sa.sll_addr, 0xFF, ETHER_ADDRLEN);
389
390    if (sendto(fd, packet, packet_len, 0, (struct sockaddr*) &sa, sizeof(sa)) < 0) {
391        daemon_log(LOG_ERR, "sendto() failed: %s", strerror(errno));
392        return -1;
393    }
394
395    return 0;
396}
397
398static int recv_packet(int fd, void **packet, size_t *packet_len) {
399    int s;
400    struct sockaddr_ll sa;
401    socklen_t sa_len;
402    ssize_t r;
403
404    assert(fd >= 0);
405    assert(packet);
406    assert(packet_len);
407
408    *packet = NULL;
409
410    if (ioctl(fd, FIONREAD, &s) < 0) {
411        daemon_log(LOG_ERR, "FIONREAD failed: %s", strerror(errno));
412        goto fail;
413    }
414
415    if (s <= 0)
416        s = 4096;
417
418    *packet = avahi_new(uint8_t, s);
419
420    sa_len = sizeof(sa);
421    if ((r = recvfrom(fd, *packet, s, 0, (struct sockaddr*) &sa, &sa_len)) < 0) {
422        daemon_log(LOG_ERR, "recvfrom() failed: %s", strerror(errno));
423        goto fail;
424    }
425
426    *packet_len = (size_t) r;
427
428    return 0;
429
430fail:
431    if (*packet) {
432        avahi_free(*packet);
433        *packet = NULL;
434    }
435
436    return -1;
437}
438
439int is_ll_address(uint32_t addr) {
440    return (ntohl(addr) & IPV4LL_NETMASK) == IPV4LL_NETWORK;
441}
442
443static struct timeval *elapse_time(struct timeval *tv, unsigned msec, unsigned jitter) {
444    assert(tv);
445
446    gettimeofday(tv, NULL);
447
448    if (msec)
449        avahi_timeval_add(tv, (AvahiUsec) msec*1000);
450
451    if (jitter)
452        avahi_timeval_add(tv, (AvahiUsec) (jitter*1000.0*rand()/(RAND_MAX+1.0)));
453
454    return tv;
455}
456
457static FILE* fork_dispatcher(void) {
458    FILE *ret;
459    int fds[2];
460    pid_t pid;
461
462    if (pipe(fds) < 0) {
463        daemon_log(LOG_ERR, "pipe() failed: %s", strerror(errno));
464        goto fail;
465    }
466
467    if ((pid = fork()) < 0)
468        goto fail;
469    else if (pid == 0) {
470        FILE *f = NULL;
471        int r = 1;
472
473        /* Please note that the signal pipe is not closed at this
474         * point, signals will thus be dispatched in the main
475         * process. */
476
477        daemon_retval_done();
478
479        setsid();
480
481        avahi_set_proc_title(argv0, "%s: [%s] callout dispatcher", argv0, interface_name);
482
483        close(fds[1]);
484
485        if (!(f = fdopen(fds[0], "r"))) {
486            daemon_log(LOG_ERR, "fdopen() failed: %s", strerror(errno));
487            goto dispatcher_fail;
488        }
489
490        for (;;) {
491            CalloutEventInfo info;
492            char name[IFNAMSIZ], buf[64];
493            int k;
494
495            if (fread(&info, sizeof(info), 1, f) != 1) {
496                if (feof(f))
497                    break;
498
499                daemon_log(LOG_ERR, "fread() failed: %s", strerror(errno));
500                goto dispatcher_fail;
501            }
502
503            assert(info.event <= CALLOUT_MAX);
504
505            if (!if_indextoname(info.ifindex, name)) {
506                daemon_log(LOG_ERR, "if_indextoname() failed: %s", strerror(errno));
507                continue;
508            }
509
510            if (daemon_exec("/", &k,
511                            AVAHI_IPCONF_SCRIPT, AVAHI_IPCONF_SCRIPT,
512                            callout_event_table[info.event],
513                            name,
514                            inet_ntop(AF_INET, &info.address, buf, sizeof(buf)), NULL) < 0) {
515
516                daemon_log(LOG_ERR, "Failed to run script: %s", strerror(errno));
517                continue;
518            }
519
520            if (k != 0)
521                daemon_log(LOG_WARNING, "Script execution failed with return value %i", k);
522        }
523
524        r = 0;
525
526    dispatcher_fail:
527
528        if (f)
529            fclose(f);
530
531        _exit(r);
532    }
533
534    /* parent */
535
536    close(fds[0]);
537    fds[0] = -1;
538
539    if (!(ret = fdopen(fds[1], "w"))) {
540        daemon_log(LOG_ERR, "fdopen() failed: %s", strerror(errno));
541        goto fail;
542    }
543
544    return ret;
545
546fail:
547    if (fds[0] >= 0)
548        close(fds[0]);
549    if (fds[1] >= 0)
550        close(fds[1]);
551
552    return NULL;
553}
554
555static int do_callout(FILE *f, CalloutEvent event, int iface, uint32_t addr) {
556    CalloutEventInfo info;
557    char buf[64], ifname[IFNAMSIZ];
558
559    daemon_log(LOG_INFO, "Callout %s, address %s on interface %s",
560               callout_event_table[event],
561               inet_ntop(AF_INET, &addr, buf, sizeof(buf)),
562               if_indextoname(iface, ifname));
563
564    info.event = event;
565    info.ifindex = iface;
566    info.address = addr;
567
568    if (fwrite(&info, sizeof(info), 1, f) != 1 || fflush(f) != 0) {
569        daemon_log(LOG_ERR, "Failed to write callout event: %s", strerror(errno));
570        return -1;
571    }
572
573    return 0;
574}
575
576static int loop(int iface, uint32_t addr) {
577    enum {
578        FD_ARP,
579        FD_IFACE,
580        FD_SIGNAL,
581        FD_MAX,
582    };
583
584    int fd = -1, ret = -1;
585    struct timeval next_wakeup;
586    int next_wakeup_valid = 0;
587    char buf[64];
588    void *in_packet = NULL;
589    size_t in_packet_len;
590    void *out_packet = NULL;
591    size_t out_packet_len;
592    uint8_t hw_address[ETHER_ADDRLEN];
593    struct pollfd pollfds[FD_MAX];
594    int iface_fd;
595    Event event = EVENT_NULL;
596    int retval_sent = !daemonize;
597    State st;
598    FILE *dispatcher = NULL;
599
600    daemon_signal_init(SIGINT, SIGTERM, SIGCHLD, SIGHUP,0);
601
602    if (!(dispatcher = fork_dispatcher()))
603        goto fail;
604
605    if ((fd = open_socket(iface, hw_address)) < 0)
606        goto fail;
607
608    if ((iface_fd = iface_init(iface)) < 0)
609        goto fail;
610
611/*     if (drop_privs() < 0) */
612/*         goto fail; */
613
614    if (force_bind)
615        st = STATE_START;
616    else if (iface_get_initial_state(&st) < 0)
617        goto fail;
618
619    if (addr && !is_ll_address(addr)) {
620        daemon_log(LOG_WARNING, "Requested address %s is not from IPv4LL range 169.254/16, ignoring.", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
621        addr = 0;
622    }
623
624    if (!addr) {
625        int i;
626        uint32_t a = 1;
627
628        for (i = 0; i < ETHER_ADDRLEN; i++)
629            a += hw_address[i]*i;
630
631        addr = htonl(IPV4LL_NETWORK | (uint32_t) a);
632    }
633
634    set_state(st, 1, addr);
635
636    daemon_log(LOG_INFO, "Starting with address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
637
638    if (state == STATE_SLEEPING)
639        daemon_log(LOG_INFO, "Routable address already assigned, sleeping.");
640
641    if (!retval_sent && (!wait_for_address || state == STATE_SLEEPING)) {
642        daemon_retval_send(0);
643        retval_sent = 1;
644    }
645
646    memset(pollfds, 0, sizeof(pollfds));
647    pollfds[FD_ARP].fd = fd;
648    pollfds[FD_ARP].events = POLLIN;
649    pollfds[FD_IFACE].fd = iface_fd;
650    pollfds[FD_IFACE].events = POLLIN;
651    pollfds[FD_SIGNAL].fd = daemon_signal_fd();
652    pollfds[FD_SIGNAL].events = POLLIN;
653
654    for (;;) {
655        int r, timeout;
656        AvahiUsec usec;
657
658        if (state == STATE_START) {
659
660            /* First, wait a random time */
661            set_state(STATE_WAITING_PROBE, 1, addr);
662
663            elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
664            next_wakeup_valid = 1;
665
666        } else if ((state == STATE_WAITING_PROBE && event == EVENT_TIMEOUT) ||
667                   (state == STATE_PROBING && event == EVENT_TIMEOUT && n_iteration < PROBE_NUM-2)) {
668
669            /* Send a probe */
670            out_packet = packet_new_probe(addr, hw_address, &out_packet_len);
671            set_state(STATE_PROBING, 0, addr);
672
673            elapse_time(&next_wakeup, PROBE_MIN*1000, (PROBE_MAX-PROBE_MIN)*1000);
674            next_wakeup_valid = 1;
675
676        } else if (state == STATE_PROBING && event == EVENT_TIMEOUT && n_iteration >= PROBE_NUM-2) {
677
678            /* Send the last probe */
679            out_packet = packet_new_probe(addr, hw_address, &out_packet_len);
680            set_state(STATE_WAITING_ANNOUNCE, 1, addr);
681
682            elapse_time(&next_wakeup, ANNOUNCE_WAIT*1000, 0);
683            next_wakeup_valid = 1;
684
685        } else if ((state == STATE_WAITING_ANNOUNCE && event == EVENT_TIMEOUT) ||
686                   (state == STATE_ANNOUNCING && event == EVENT_TIMEOUT && n_iteration < ANNOUNCE_NUM-1)) {
687
688            /* Send announcement packet */
689            out_packet = packet_new_announcement(addr, hw_address, &out_packet_len);
690            set_state(STATE_ANNOUNCING, 0, addr);
691
692            elapse_time(&next_wakeup, ANNOUNCE_INTERVAL*1000, 0);
693            next_wakeup_valid = 1;
694
695            if (n_iteration == 0) {
696                if (do_callout(dispatcher, CALLOUT_BIND, iface, addr) < 0)
697                    goto fail;
698
699                n_conflict = 0;
700
701                if (!retval_sent) {
702                    daemon_retval_send(0);
703                    retval_sent = 1;
704                }
705            }
706
707        } else if ((state == STATE_ANNOUNCING && event == EVENT_TIMEOUT && n_iteration >= ANNOUNCE_NUM-1)) {
708
709            daemon_log(LOG_INFO, "Successfully claimed IP address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
710            set_state(STATE_RUNNING, 0, addr);
711
712            next_wakeup_valid = 0;
713
714        } else if (event == EVENT_PACKET) {
715            ArpPacketInfo info;
716
717            assert(in_packet);
718
719            if (packet_parse(in_packet, in_packet_len, &info) < 0)
720                daemon_log(LOG_WARNING, "Failed to parse incoming ARP packet.");
721            else {
722                int conflict = 0;
723
724                if (info.sender_ip_address == addr) {
725                    /* Normal conflict */
726                    conflict = 1;
727                    daemon_log(LOG_INFO, "Recieved conflicting normal ARP packet.");
728                } else if (state == STATE_WAITING_PROBE || state == STATE_PROBING || state == STATE_WAITING_ANNOUNCE) {
729                    /* Probe conflict */
730                    conflict = info.target_ip_address == addr && memcmp(hw_address, info.sender_hw_address, ETHER_ADDRLEN);
731                    daemon_log(LOG_INFO, "Recieved conflicting probe ARP packet.");
732                }
733
734                if (conflict) {
735
736                    if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
737                        if (do_callout(dispatcher, CALLOUT_CONFLICT, iface, addr) < 0)
738                            goto fail;
739
740                    /* Pick a new address */
741                    addr = pick_addr(addr);
742
743                    daemon_log(LOG_INFO, "Trying address %s", inet_ntop(AF_INET, &addr, buf, sizeof(buf)));
744
745                    n_conflict++;
746
747                    set_state(STATE_WAITING_PROBE, 1, addr);
748
749                    if (n_conflict >= MAX_CONFLICTS) {
750                        daemon_log(LOG_WARNING, "Got too many conflicts, rate limiting new probes.");
751                        elapse_time(&next_wakeup, RATE_LIMIT_INTERVAL*1000, PROBE_WAIT*1000);
752                    } else
753                        elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
754
755                    next_wakeup_valid = 1;
756                } else
757                    DEBUG(daemon_log(LOG_DEBUG, "Ignoring irrelevant ARP packet."));
758            }
759
760        } else if (event == EVENT_ROUTABLE_ADDR_CONFIGURED) {
761
762            daemon_log(LOG_INFO, "A routable address has been configured.");
763
764            if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
765                if (do_callout(dispatcher, CALLOUT_UNBIND, iface, addr) < 0)
766                    goto fail;
767
768            if (!retval_sent) {
769                daemon_retval_send(0);
770                retval_sent = 1;
771            }
772
773            set_state(STATE_SLEEPING, 1, addr);
774            next_wakeup_valid = 0;
775
776        } else if (event == EVENT_ROUTABLE_ADDR_UNCONFIGURED && state == STATE_SLEEPING && !force_bind) {
777
778            daemon_log(LOG_INFO, "No longer a routable address configured, restarting probe process.");
779
780            set_state(STATE_WAITING_PROBE, 1, addr);
781
782            elapse_time(&next_wakeup, 0, PROBE_WAIT*1000);
783            next_wakeup_valid = 1;
784
785        } else if (event == EVENT_REFRESH_REQUEST && state == STATE_RUNNING && !force_bind) {
786
787            /* The user requested a reannouncing of the address by a SIGHUP */
788            daemon_log(LOG_INFO, "Reannouncing address.");
789
790            /* Send announcement packet */
791            out_packet = packet_new_announcement(addr, hw_address, &out_packet_len);
792            set_state(STATE_ANNOUNCING, 1, addr);
793
794            elapse_time(&next_wakeup, ANNOUNCE_INTERVAL*1000, 0);
795            next_wakeup_valid = 1;
796        }
797
798        if (out_packet) {
799            DEBUG(daemon_log(LOG_DEBUG, "sending..."));
800
801            if (send_packet(fd, iface, out_packet, out_packet_len) < 0)
802                goto fail;
803
804            avahi_free(out_packet);
805            out_packet = NULL;
806        }
807
808        if (in_packet) {
809            avahi_free(in_packet);
810            in_packet = NULL;
811        }
812
813        event = EVENT_NULL;
814        timeout = -1;
815
816        if (next_wakeup_valid) {
817            usec = avahi_age(&next_wakeup);
818            timeout = usec < 0 ? (int) (-usec/1000) : 0;
819        }
820
821        DEBUG(daemon_log(LOG_DEBUG, "sleeping %ims", timeout));
822
823        while ((r = poll(pollfds, FD_MAX, timeout)) < 0 && errno == EINTR)
824            ;
825
826        if (r < 0) {
827            daemon_log(LOG_ERR, "poll() failed: %s", strerror(r));
828            goto fail;
829        } else if (r == 0) {
830            event = EVENT_TIMEOUT;
831            next_wakeup_valid = 0;
832        } else {
833
834
835            if (pollfds[FD_ARP].revents) {
836
837                if (pollfds[FD_ARP].revents == POLLERR) {
838                    /* The interface is probably down, let's recreate our socket */
839
840                    close(fd);
841
842                    if ((fd = open_socket(iface, hw_address)) < 0)
843                        goto fail;
844
845                    pollfds[FD_ARP].fd = fd;
846
847                } else {
848
849                    assert(pollfds[FD_ARP].revents == POLLIN);
850
851                    if (recv_packet(fd, &in_packet, &in_packet_len) < 0)
852                        goto fail;
853
854                    if (in_packet)
855                        event = EVENT_PACKET;
856                }
857            }
858
859            if (event == EVENT_NULL &&
860                pollfds[FD_IFACE].revents) {
861
862                assert(pollfds[FD_IFACE].revents == POLLIN);
863
864                if (iface_process(&event) < 0)
865                    goto fail;
866            }
867
868            if (event == EVENT_NULL &&
869                pollfds[FD_SIGNAL].revents) {
870
871                int sig;
872                assert(pollfds[FD_SIGNAL].revents == POLLIN);
873
874                if ((sig = daemon_signal_next()) <= 0) {
875                    daemon_log(LOG_ERR, "daemon_signal_next() failed");
876                    goto fail;
877                }
878
879                switch(sig) {
880                    case SIGINT:
881                    case SIGTERM:
882                        daemon_log(LOG_INFO, "Got %s, quitting.", sig == SIGINT ? "SIGINT" : "SIGTERM");
883                        ret = 0;
884                        goto fail;
885
886                    case SIGCHLD:
887                        waitpid(-1, NULL, WNOHANG);
888                        break;
889
890                    case SIGHUP:
891                        event = EVENT_REFRESH_REQUEST;
892                        break;
893                }
894
895            }
896        }
897    }
898
899    ret = 0;
900
901fail:
902
903    if (state == STATE_RUNNING || state == STATE_ANNOUNCING)
904        do_callout(dispatcher, CALLOUT_STOP, iface, addr);
905
906    avahi_free(out_packet);
907    avahi_free(in_packet);
908
909    if (fd >= 0)
910        close(fd);
911
912    if (iface_fd >= 0)
913        iface_done();
914
915    if (daemonize && !retval_sent)
916        daemon_retval_send(ret);
917
918    if (dispatcher)
919        fclose(dispatcher);
920
921    return ret;
922}
923
924
925static void help(FILE *f, const char *a0) {
926    fprintf(f,
927            "%s [options] INTERFACE\n"
928            "    -h --help           Show this help\n"
929            "    -D --daemonize      Daemonize after startup\n"
930            "    -s --syslog         Write log messages to syslog(3) instead of STDERR\n"
931            "    -k --kill           Kill a running daemon\n"
932            "    -r --refresh        Request a running daemon to refresh it's IP address\n"
933            "    -c --check          Return 0 if a daemon is already running\n"
934            "    -V --version        Show version\n"
935            "    -S --start=ADDRESS  Start with this address from the IPv4LL range\n"
936            "                        169.254.0.0/16\n"
937            "    -w --wait           Wait until an address has been acquired before\n"
938            "                        daemonizing\n"
939            "       --no-proc-title  Don't modify process title\n"
940            "       --force-bind     Assign an IPv4LL address even if routable address\n"
941            "                        is already assigned\n"
942            "       --debug          Increase verbosity\n",
943            a0);
944}
945
946static int parse_command_line(int argc, char *argv[]) {
947    int c;
948
949    enum {
950        OPTION_NO_PROC_TITLE = 256,
951        OPTION_FORCE_BIND,
952        OPTION_DEBUG
953    };
954
955    static const struct option long_options[] = {
956        { "help",          no_argument,       NULL, 'h' },
957        { "daemonize",     no_argument,       NULL, 'D' },
958        { "syslog",        no_argument,       NULL, 's' },
959        { "kill",          no_argument,       NULL, 'k' },
960        { "refresh",       no_argument,       NULL, 'r' },
961        { "check",         no_argument,       NULL, 'c' },
962        { "version",       no_argument,       NULL, 'V' },
963        { "start",         required_argument, NULL, 'S' },
964        { "wait",          no_argument,       NULL, 'w' },
965        { "no-proc-title", no_argument,       NULL, OPTION_NO_PROC_TITLE },
966        { "force-bind",    no_argument,       NULL, OPTION_FORCE_BIND },
967        { "debug",         no_argument,       NULL, OPTION_DEBUG },
968        { NULL, 0, NULL, 0 }
969    };
970
971    opterr = 0;
972    while ((c = getopt_long(argc, argv, "hDskrcVS:w", long_options, NULL)) >= 0) {
973
974        switch(c) {
975            case 's':
976                use_syslog = 1;
977                break;
978            case 'h':
979                command = DAEMON_HELP;
980                break;
981            case 'D':
982                daemonize = 1;
983                break;
984            case 'k':
985                command = DAEMON_KILL;
986                break;
987            case 'V':
988                command = DAEMON_VERSION;
989                break;
990            case 'r':
991                command = DAEMON_REFRESH;
992                break;
993            case 'c':
994                command = DAEMON_CHECK;
995                break;
996            case 'S':
997
998                if ((start_address = inet_addr(optarg)) == (uint32_t) -1) {
999                    fprintf(stderr, "Failed to parse IP address '%s'.", optarg);
1000                    return -1;
1001                }
1002                break;
1003            case 'w':
1004                wait_for_address = 1;
1005                break;
1006
1007            case OPTION_NO_PROC_TITLE:
1008                modify_proc_title = 0;
1009                break;
1010
1011            case OPTION_DEBUG:
1012                debug = 1;
1013                break;
1014
1015            case OPTION_FORCE_BIND:
1016                force_bind = 1;
1017                break;
1018
1019            default:
1020                fprintf(stderr, "Invalid command line argument: %c\n", c);
1021                return -1;
1022        }
1023    }
1024
1025    if (command == DAEMON_RUN ||
1026        command == DAEMON_KILL ||
1027        command == DAEMON_REFRESH ||
1028        command == DAEMON_CHECK) {
1029
1030        if (optind >= argc) {
1031            fprintf(stderr, "Missing interface name.\n");
1032            return -1;
1033        }
1034
1035        interface_name = avahi_strdup(argv[optind++]);
1036    }
1037
1038    if (optind != argc) {
1039        fprintf(stderr, "Too many arguments\n");
1040        return -1;
1041    }
1042
1043    return 0;
1044}
1045
1046static const char* pid_file_proc(void) {
1047    return pid_file_name;
1048}
1049
1050int main(int argc, char*argv[]) {
1051    int r = 1;
1052    int wrote_pid_file = 0;
1053    char *log_ident = NULL;
1054
1055    avahi_init_proc_title(argc, argv);
1056
1057    signal(SIGPIPE, SIG_IGN);
1058
1059    if ((argv0 = strrchr(argv[0], '/')))
1060        argv0++;
1061    else
1062        argv0 = argv[0];
1063
1064    argv0 = avahi_strdup(argv0);
1065
1066    daemon_log_ident = argv0;
1067
1068    if (parse_command_line(argc, argv) < 0)
1069        goto finish;
1070
1071    daemon_log_ident = log_ident = avahi_strdup_printf("%s(%s)", argv0, interface_name);
1072    daemon_pid_file_proc = pid_file_proc;
1073    pid_file_name = avahi_strdup_printf(AVAHI_RUNTIME_DIR"/avahi-autoipd.%s.pid", interface_name);
1074
1075    if (command == DAEMON_RUN) {
1076        pid_t pid;
1077        int ifindex;
1078
1079        init_rand_seed();
1080
1081        if ((ifindex = if_nametoindex(interface_name)) <= 0) {
1082            daemon_log(LOG_ERR, "Failed to get index for interface name '%s': %s", interface_name, strerror(errno));
1083            goto finish;
1084        }
1085
1086        if (getuid() != 0) {
1087            daemon_log(LOG_ERR, "This program is intended to be run as root.");
1088            goto finish;
1089        }
1090
1091        if ((pid = daemon_pid_file_is_running()) >= 0) {
1092            daemon_log(LOG_ERR, "Daemon already running on PID %u", pid);
1093            goto finish;
1094        }
1095
1096        if (daemonize) {
1097            daemon_retval_init();
1098
1099            if ((pid = daemon_fork()) < 0)
1100                goto finish;
1101            else if (pid != 0) {
1102                int ret;
1103                /** Parent **/
1104
1105                if ((ret = daemon_retval_wait(20)) < 0) {
1106                    daemon_log(LOG_ERR, "Could not receive return value from daemon process.");
1107                    goto finish;
1108                }
1109
1110                r = ret;
1111                goto finish;
1112            }
1113
1114            /* Child */
1115        }
1116
1117        if (use_syslog || daemonize)
1118            daemon_log_use = DAEMON_LOG_SYSLOG;
1119
1120        chdir("/");
1121
1122        if (daemon_pid_file_create() < 0) {
1123            daemon_log(LOG_ERR, "Failed to create PID file: %s", strerror(errno));
1124
1125            if (daemonize)
1126                daemon_retval_send(1);
1127            goto finish;
1128        } else
1129            wrote_pid_file = 1;
1130
1131        avahi_set_proc_title(argv0, "%s: [%s] starting up", argv0, interface_name);
1132
1133        if (loop(ifindex, start_address) < 0)
1134            goto finish;
1135
1136        r = 0;
1137    } else if (command == DAEMON_HELP) {
1138        help(stdout, argv0);
1139
1140        r = 0;
1141    } else if (command == DAEMON_VERSION) {
1142        printf("%s "PACKAGE_VERSION"\n", argv0);
1143
1144        r = 0;
1145    } else if (command == DAEMON_KILL) {
1146        if (daemon_pid_file_kill_wait(SIGTERM, 5) < 0) {
1147            daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
1148            goto finish;
1149        }
1150
1151        r = 0;
1152    } else if (command == DAEMON_REFRESH) {
1153        if (daemon_pid_file_kill(SIGHUP) < 0) {
1154            daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
1155            goto finish;
1156        }
1157
1158        r = 0;
1159    } else if (command == DAEMON_CHECK)
1160        r = (daemon_pid_file_is_running() >= 0) ? 0 : 1;
1161
1162
1163finish:
1164
1165    if (daemonize)
1166        daemon_retval_done();
1167
1168    if (wrote_pid_file)
1169        daemon_pid_file_remove();
1170
1171    avahi_free(log_ident);
1172    avahi_free(pid_file_name);
1173    avahi_free(argv0);
1174    avahi_free(interface_name);
1175
1176    return r;
1177}
1178
1179/* TODO:
1180
1181- chroot/drop privs/caps
1182- store last used address
1183- man page
1184
1185*/
1186