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 <inttypes.h>
27#include <errno.h>
28#include <string.h>
29#include <stdio.h>
30#include <unistd.h>
31#include <fcntl.h>
32#include <sys/time.h>
33#include <sys/ioctl.h>
34#ifdef HAVE_SYS_FILIO_H
35#include <sys/filio.h>
36#endif
37#include <assert.h>
38
39#include <sys/types.h>
40#include <sys/socket.h>
41#include <netinet/in.h>
42#include <arpa/inet.h>
43#include <net/if.h>
44#include <sys/uio.h>
45
46#ifdef IP_RECVIF
47#include <net/if_dl.h>
48#endif
49
50#include "dns.h"
51#include "fdutil.h"
52#include "socket.h"
53#include "log.h"
54#include "addr-util.h"
55
56/* this is a portability hack */
57#ifndef IPV6_ADD_MEMBERSHIP
58#ifdef  IPV6_JOIN_GROUP
59#define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
60#endif
61#endif
62
63#ifndef IPV6_DROP_MEMBERSHIP
64#ifdef  IPV6_LEAVE_GROUP
65#define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
66#endif
67#endif
68
69static void mdns_mcast_group_ipv4(struct sockaddr_in *ret_sa) {
70    assert(ret_sa);
71
72    memset(ret_sa, 0, sizeof(struct sockaddr_in));
73    ret_sa->sin_family = AF_INET;
74    ret_sa->sin_port = htons(AVAHI_MDNS_PORT);
75    inet_pton(AF_INET, AVAHI_IPV4_MCAST_GROUP, &ret_sa->sin_addr);
76}
77
78static void mdns_mcast_group_ipv6(struct sockaddr_in6 *ret_sa) {
79    assert(ret_sa);
80
81    memset(ret_sa, 0, sizeof(struct sockaddr_in6));
82    ret_sa->sin6_family = AF_INET6;
83    ret_sa->sin6_port = htons(AVAHI_MDNS_PORT);
84    inet_pton(AF_INET6, AVAHI_IPV6_MCAST_GROUP, &ret_sa->sin6_addr);
85}
86
87static void ipv4_address_to_sockaddr(struct sockaddr_in *ret_sa, const AvahiIPv4Address *a, uint16_t port) {
88    assert(ret_sa);
89    assert(a);
90    assert(port > 0);
91
92    memset(ret_sa, 0, sizeof(struct sockaddr_in));
93    ret_sa->sin_family = AF_INET;
94    ret_sa->sin_port = htons(port);
95    memcpy(&ret_sa->sin_addr, a, sizeof(AvahiIPv4Address));
96}
97
98static void ipv6_address_to_sockaddr(struct sockaddr_in6 *ret_sa, const AvahiIPv6Address *a, uint16_t port) {
99    assert(ret_sa);
100    assert(a);
101    assert(port > 0);
102
103    memset(ret_sa, 0, sizeof(struct sockaddr_in6));
104    ret_sa->sin6_family = AF_INET6;
105    ret_sa->sin6_port = htons(port);
106    memcpy(&ret_sa->sin6_addr, a, sizeof(AvahiIPv6Address));
107}
108
109int avahi_mdns_mcast_join_ipv4(int fd, const AvahiIPv4Address *a, int idx, int join) {
110#ifdef HAVE_STRUCT_IP_MREQN
111    struct ip_mreqn mreq;
112#else
113    struct ip_mreq mreq;
114#endif
115    struct sockaddr_in sa;
116
117    assert(fd >= 0);
118    assert(idx >= 0);
119    assert(a);
120
121    memset(&mreq, 0, sizeof(mreq));
122#ifdef HAVE_STRUCT_IP_MREQN
123    mreq.imr_ifindex = idx;
124    mreq.imr_address.s_addr = a->address;
125#else
126    mreq.imr_interface.s_addr = a->address;
127#endif
128    mdns_mcast_group_ipv4(&sa);
129    mreq.imr_multiaddr = sa.sin_addr;
130
131    /* Some network drivers have issues with dropping membership of
132     * mcast groups when the iface is down, but don't allow rejoining
133     * when it comes back up. This is an ugly workaround */
134    if (join)
135        setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
136
137    if (setsockopt(fd, IPPROTO_IP, join ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) {
138        avahi_log_warn("%s failed: %s", join ? "IP_ADD_MEMBERSHIP" : "IP_DROP_MEMBERSHIP", strerror(errno));
139        return -1;
140    }
141
142    return 0;
143}
144
145int avahi_mdns_mcast_join_ipv6(int fd, const AvahiIPv6Address *a, int idx, int join) {
146    struct ipv6_mreq mreq6;
147    struct sockaddr_in6 sa6;
148
149    assert(fd >= 0);
150    assert(idx >= 0);
151    assert(a);
152
153    memset(&mreq6, 0, sizeof(mreq6));
154    mdns_mcast_group_ipv6 (&sa6);
155    mreq6.ipv6mr_multiaddr = sa6.sin6_addr;
156    mreq6.ipv6mr_interface = idx;
157
158    if (join)
159        setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
160
161    if (setsockopt(fd, IPPROTO_IPV6, join ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6)) < 0) {
162        avahi_log_warn("%s failed: %s", join ? "IPV6_ADD_MEMBERSHIP" : "IPV6_DROP_MEMBERSHIP", strerror(errno));
163        return -1;
164    }
165
166    return 0;
167}
168
169static int reuseaddr(int fd) {
170    int yes;
171
172    yes = 1;
173    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
174        avahi_log_warn("SO_REUSEADDR failed: %s", strerror(errno));
175        return -1;
176    }
177
178#ifdef SO_REUSEPORT
179    yes = 1;
180    if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &yes, sizeof(yes)) < 0) {
181        avahi_log_warn("SO_REUSEPORT failed: %s", strerror(errno));
182        return -1;
183    }
184#endif
185
186    return 0;
187}
188
189static int bind_with_warn(int fd, const struct sockaddr *sa, socklen_t l) {
190
191    assert(fd >= 0);
192    assert(sa);
193    assert(l > 0);
194
195    if (bind(fd, sa, l) < 0) {
196
197        if (errno != EADDRINUSE) {
198            avahi_log_warn("bind() failed: %s", strerror(errno));
199            return -1;
200        }
201
202        avahi_log_warn("*** WARNING: Detected another %s mDNS stack running on this host. This makes mDNS unreliable and is thus not recommended. ***",
203                       sa->sa_family == AF_INET ? "IPv4" : "IPv6");
204
205        /* Try again, this time with SO_REUSEADDR set */
206        if (reuseaddr(fd) < 0)
207            return -1;
208
209        if (bind(fd, sa, l) < 0) {
210            avahi_log_warn("bind() failed: %s", strerror(errno));
211            return -1;
212        }
213    } else {
214
215        /* We enable SO_REUSEADDR afterwards, to make sure that the
216         * user may run other mDNS implementations if he really
217         * wants. */
218
219        if (reuseaddr(fd) < 0)
220            return -1;
221    }
222
223    return 0;
224}
225
226static int ipv4_pktinfo(int fd) {
227    int yes;
228
229#ifdef IP_PKTINFO
230    yes = 1;
231    if (setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &yes, sizeof(yes)) < 0) {
232        avahi_log_warn("IP_PKTINFO failed: %s", strerror(errno));
233        return -1;
234    }
235#else
236
237#ifdef IP_RECVINTERFACE
238    yes = 1;
239    if (setsockopt (fd, IPPROTO_IP, IP_RECVINTERFACE, &yes, sizeof(yes)) < 0) {
240        avahi_log_warn("IP_RECVINTERFACE failed: %s", strerror(errno));
241        return -1;
242    }
243#elif defined(IP_RECVIF)
244    yes = 1;
245    if (setsockopt (fd, IPPROTO_IP, IP_RECVIF, &yes, sizeof(yes)) < 0) {
246        avahi_log_warn("IP_RECVIF failed: %s", strerror(errno));
247        return -1;
248    }
249#endif
250
251#ifdef IP_RECVDSTADDR
252    yes = 1;
253    if (setsockopt (fd, IPPROTO_IP, IP_RECVDSTADDR, &yes, sizeof(yes)) < 0) {
254        avahi_log_warn("IP_RECVDSTADDR failed: %s", strerror(errno));
255        return -1;
256    }
257#endif
258
259#endif /* IP_PKTINFO */
260
261#ifdef IP_RECVTTL
262    yes = 1;
263    if (setsockopt(fd, IPPROTO_IP, IP_RECVTTL, &yes, sizeof(yes)) < 0) {
264        avahi_log_warn("IP_RECVTTL failed: %s", strerror(errno));
265        return -1;
266    }
267#endif
268
269    return 0;
270}
271
272static int ipv6_pktinfo(int fd) {
273    int yes;
274
275#ifdef IPV6_RECVPKTINFO
276    yes = 1;
277    if (setsockopt(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &yes, sizeof(yes)) < 0) {
278        avahi_log_warn("IPV6_RECVPKTINFO failed: %s", strerror(errno));
279        return -1;
280    }
281#elif defined(IPV6_PKTINFO)
282    yes = 1;
283    if (setsockopt(fd, IPPROTO_IPV6, IPV6_PKTINFO, &yes, sizeof(yes)) < 0) {
284        avahi_log_warn("IPV6_PKTINFO failed: %s", strerror(errno));
285        return -1;
286    }
287#endif
288
289#ifdef IPV6_RECVHOPS
290    yes = 1;
291    if (setsockopt(fd, IPPROTO_IPV6, IPV6_RECVHOPS, &yes, sizeof(yes)) < 0) {
292        avahi_log_warn("IPV6_RECVHOPS failed: %s", strerror(errno));
293        return -1;
294    }
295#elif defined(IPV6_RECVHOPLIMIT)
296    yes = 1;
297    if (setsockopt(fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &yes, sizeof(yes)) < 0) {
298        avahi_log_warn("IPV6_RECVHOPLIMIT failed: %s", strerror(errno));
299        return -1;
300    }
301#elif defined(IPV6_HOPLIMIT)
302    yes = 1;
303    if (setsockopt(fd, IPPROTO_IPV6, IPV6_HOPLIMIT, &yes, sizeof(yes)) < 0) {
304        avahi_log_warn("IPV6_HOPLIMIT failed: %s", strerror(errno));
305        return -1;
306    }
307#endif
308
309    return 0;
310}
311
312int avahi_open_socket_ipv4(int no_reuse) {
313    struct sockaddr_in local;
314    int fd = -1, r, ittl;
315    uint8_t ttl, cyes;
316
317    if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
318        avahi_log_warn("socket() failed: %s", strerror(errno));
319        goto fail;
320    }
321
322    ttl = 255;
323    if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0) {
324        avahi_log_warn("IP_MULTICAST_TTL failed: %s", strerror(errno));
325        goto fail;
326    }
327
328    ittl = 255;
329    if (setsockopt(fd, IPPROTO_IP, IP_TTL, &ittl, sizeof(ittl)) < 0) {
330        avahi_log_warn("IP_TTL failed: %s", strerror(errno));
331        goto fail;
332    }
333
334    cyes = 1;
335    if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &cyes, sizeof(cyes)) < 0) {
336        avahi_log_warn("IP_MULTICAST_LOOP failed: %s", strerror(errno));
337        goto fail;
338    }
339
340    memset(&local, 0, sizeof(local));
341    local.sin_family = AF_INET;
342    local.sin_port = htons(AVAHI_MDNS_PORT);
343
344    if (no_reuse)
345        r = bind(fd, (struct sockaddr*) &local, sizeof(local));
346    else
347        r = bind_with_warn(fd, (struct sockaddr*) &local, sizeof(local));
348
349    if (r < 0)
350        goto fail;
351
352    if (ipv4_pktinfo (fd) < 0)
353         goto fail;
354
355    if (avahi_set_cloexec(fd) < 0) {
356        avahi_log_warn("FD_CLOEXEC failed: %s", strerror(errno));
357        goto fail;
358    }
359
360    if (avahi_set_nonblock(fd) < 0) {
361        avahi_log_warn("O_NONBLOCK failed: %s", strerror(errno));
362        goto fail;
363    }
364
365    return fd;
366
367fail:
368    if (fd >= 0)
369        close(fd);
370
371    return -1;
372}
373
374int avahi_open_socket_ipv6(int no_reuse) {
375    struct sockaddr_in6 sa, local;
376    int fd = -1, yes, r;
377    int ttl;
378
379    mdns_mcast_group_ipv6(&sa);
380
381    if ((fd = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
382        avahi_log_warn("socket() failed: %s", strerror(errno));
383        goto fail;
384    }
385
386    ttl = 255;
387    if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0) {
388        avahi_log_warn("IPV6_MULTICAST_HOPS failed: %s", strerror(errno));
389        goto fail;
390    }
391
392    ttl = 255;
393    if (setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)) < 0) {
394        avahi_log_warn("IPV6_UNICAST_HOPS failed: %s", strerror(errno));
395        goto fail;
396    }
397
398    yes = 1;
399    if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &yes, sizeof(yes)) < 0) {
400        avahi_log_warn("IPV6_V6ONLY failed: %s", strerror(errno));
401        goto fail;
402    }
403
404    yes = 1;
405    if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &yes, sizeof(yes)) < 0) {
406        avahi_log_warn("IPV6_MULTICAST_LOOP failed: %s", strerror(errno));
407        goto fail;
408    }
409
410    memset(&local, 0, sizeof(local));
411    local.sin6_family = AF_INET6;
412    local.sin6_port = htons(AVAHI_MDNS_PORT);
413
414    if (no_reuse)
415        r = bind(fd, (struct sockaddr*) &local, sizeof(local));
416    else
417        r = bind_with_warn(fd, (struct sockaddr*) &local, sizeof(local));
418
419    if (r < 0)
420        goto fail;
421
422    if (ipv6_pktinfo(fd) < 0)
423        goto fail;
424
425    if (avahi_set_cloexec(fd) < 0) {
426        avahi_log_warn("FD_CLOEXEC failed: %s", strerror(errno));
427        goto fail;
428    }
429
430    if (avahi_set_nonblock(fd) < 0) {
431        avahi_log_warn("O_NONBLOCK failed: %s", strerror(errno));
432        goto fail;
433    }
434
435    return fd;
436
437fail:
438    if (fd >= 0)
439        close(fd);
440
441    return -1;
442}
443
444static int sendmsg_loop(int fd, struct msghdr *msg, int flags) {
445    assert(fd >= 0);
446    assert(msg);
447
448    for (;;) {
449
450        if (sendmsg(fd, msg, flags) >= 0)
451            break;
452
453        if (errno != EAGAIN) {
454            char where[64];
455            struct sockaddr_in *sin = msg->msg_name;
456
457            inet_ntop(sin->sin_family, &sin->sin_addr, where, sizeof(where));
458            avahi_log_debug("sendmsg() to %s failed: %s", where, strerror(errno));
459            return -1;
460        }
461
462        if (avahi_wait_for_write(fd) < 0)
463            return -1;
464    }
465
466    return 0;
467}
468
469int avahi_send_dns_packet_ipv4(
470        int fd,
471        AvahiIfIndex interface,
472        AvahiDnsPacket *p,
473        const AvahiIPv4Address *src_address,
474        const AvahiIPv4Address *dst_address,
475        uint16_t dst_port) {
476
477    struct sockaddr_in sa;
478    struct msghdr msg;
479    struct iovec io;
480#ifdef IP_PKTINFO
481    struct cmsghdr *cmsg;
482    size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_pktinfo)) / sizeof(size_t)) + 1];
483#elif !defined(IP_MULTICAST_IF) && defined(IP_SENDSRCADDR)
484    struct cmsghdr *cmsg;
485    size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_addr)) / sizeof(size_t)) + 1];
486#endif
487
488    assert(fd >= 0);
489    assert(p);
490    assert(avahi_dns_packet_check_valid(p) >= 0);
491    assert(!dst_address || dst_port > 0);
492
493    if (!dst_address)
494        mdns_mcast_group_ipv4(&sa);
495    else
496        ipv4_address_to_sockaddr(&sa, dst_address, dst_port);
497
498    memset(&io, 0, sizeof(io));
499    io.iov_base = AVAHI_DNS_PACKET_DATA(p);
500    io.iov_len = p->size;
501
502    memset(&msg, 0, sizeof(msg));
503    msg.msg_name = &sa;
504    msg.msg_namelen = sizeof(sa);
505    msg.msg_iov = &io;
506    msg.msg_iovlen = 1;
507    msg.msg_flags = 0;
508    msg.msg_control = NULL;
509    msg.msg_controllen = 0;
510
511#ifdef IP_PKTINFO
512    if (interface > 0 || src_address) {
513        struct in_pktinfo *pkti;
514
515        memset(cmsg_data, 0, sizeof(cmsg_data));
516        msg.msg_control = cmsg_data;
517        msg.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo));
518
519        cmsg = CMSG_FIRSTHDR(&msg);
520        cmsg->cmsg_len = msg.msg_controllen;
521        cmsg->cmsg_level = IPPROTO_IP;
522        cmsg->cmsg_type = IP_PKTINFO;
523
524        pkti = (struct in_pktinfo*) CMSG_DATA(cmsg);
525
526        if (interface > 0)
527            pkti->ipi_ifindex = interface;
528
529        if (src_address)
530            pkti->ipi_spec_dst.s_addr = src_address->address;
531    }
532#elif defined(IP_MULTICAST_IF)
533    if (src_address) {
534        struct in_addr any = { INADDR_ANY };
535        if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, src_address ? &src_address->address : &any, sizeof(struct in_addr)) < 0) {
536            avahi_log_warn("IP_MULTICAST_IF failed: %s", strerror(errno));
537            return -1;
538        }
539    }
540#elif defined(IP_SENDSRCADDR)
541    if (src_address) {
542        struct in_addr *addr;
543
544        memset(cmsg_data, 0, sizeof(cmsg_data));
545        msg.msg_control = cmsg_data;
546        msg.msg_controllen = CMSG_LEN(sizeof(struct in_addr));
547
548        cmsg = CMSG_FIRSTHDR(&msg);
549        cmsg->cmsg_len = msg.msg_controllen;
550        cmsg->cmsg_level = IPPROTO_IP;
551        cmsg->cmsg_type = IP_SENDSRCADDR;
552
553        addr = (struct in_addr *)CMSG_DATA(cmsg);
554        addr->s_addr =  src_address->address;
555    }
556#elif defined(__GNUC__)
557#warning "FIXME: We need some code to set the outgoing interface/local address here if IP_PKTINFO/IP_MULTICAST_IF is not available"
558#endif
559
560    return sendmsg_loop(fd, &msg, 0);
561}
562
563int avahi_send_dns_packet_ipv6(
564        int fd,
565        AvahiIfIndex interface,
566        AvahiDnsPacket *p,
567        const AvahiIPv6Address *src_address,
568        const AvahiIPv6Address *dst_address,
569        uint16_t dst_port) {
570
571    struct sockaddr_in6 sa;
572    struct msghdr msg;
573    struct iovec io;
574    struct cmsghdr *cmsg;
575    size_t cmsg_data[(CMSG_SPACE(sizeof(struct in6_pktinfo))/sizeof(size_t)) + 1];
576
577    assert(fd >= 0);
578    assert(p);
579    assert(avahi_dns_packet_check_valid(p) >= 0);
580    assert(!dst_address || dst_port > 0);
581
582    if (!dst_address)
583        mdns_mcast_group_ipv6(&sa);
584    else
585        ipv6_address_to_sockaddr(&sa, dst_address, dst_port);
586
587    memset(&io, 0, sizeof(io));
588    io.iov_base = AVAHI_DNS_PACKET_DATA(p);
589    io.iov_len = p->size;
590
591    memset(&msg, 0, sizeof(msg));
592    msg.msg_name = &sa;
593    msg.msg_namelen = sizeof(sa);
594    msg.msg_iov = &io;
595    msg.msg_iovlen = 1;
596    msg.msg_flags = 0;
597
598    if (interface > 0 || src_address) {
599        struct in6_pktinfo *pkti;
600
601        memset(cmsg_data, 0, sizeof(cmsg_data));
602        msg.msg_control = cmsg_data;
603        msg.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo));
604
605        cmsg = CMSG_FIRSTHDR(&msg);
606        cmsg->cmsg_len = msg.msg_controllen;
607        cmsg->cmsg_level = IPPROTO_IPV6;
608        cmsg->cmsg_type = IPV6_PKTINFO;
609
610        pkti = (struct in6_pktinfo*) CMSG_DATA(cmsg);
611
612        if (interface > 0)
613            pkti->ipi6_ifindex = interface;
614
615        if (src_address)
616            memcpy(&pkti->ipi6_addr, src_address->address, sizeof(src_address->address));
617    } else {
618        msg.msg_control = NULL;
619        msg.msg_controllen = 0;
620    }
621
622    return sendmsg_loop(fd, &msg, 0);
623}
624
625AvahiDnsPacket *avahi_recv_dns_packet_ipv4(
626        int fd,
627        AvahiIPv4Address *ret_src_address,
628        uint16_t *ret_src_port,
629        AvahiIPv4Address *ret_dst_address,
630        AvahiIfIndex *ret_iface,
631        uint8_t *ret_ttl) {
632
633    AvahiDnsPacket *p= NULL;
634    struct msghdr msg;
635    struct iovec io;
636    size_t aux[1024 / sizeof(size_t)]; /* for alignment on ia64 ! */
637    ssize_t l;
638    struct cmsghdr *cmsg;
639    int found_addr = 0;
640    int ms;
641    struct sockaddr_in sa;
642
643    assert(fd >= 0);
644
645    if (ioctl(fd, FIONREAD, &ms) < 0) {
646        avahi_log_warn("ioctl(): %s", strerror(errno));
647        goto fail;
648    }
649
650    if (ms < 0) {
651        avahi_log_warn("FIONREAD returned negative value.");
652        goto fail;
653    }
654
655    p = avahi_dns_packet_new(ms + AVAHI_DNS_PACKET_EXTRA_SIZE);
656
657    io.iov_base = AVAHI_DNS_PACKET_DATA(p);
658    io.iov_len = p->max_size;
659
660    memset(&msg, 0, sizeof(msg));
661    msg.msg_name = &sa;
662    msg.msg_namelen = sizeof(sa);
663    msg.msg_iov = &io;
664    msg.msg_iovlen = 1;
665    msg.msg_control = aux;
666    msg.msg_controllen = sizeof(aux);
667    msg.msg_flags = 0;
668
669    if ((l = recvmsg(fd, &msg, 0)) < 0) {
670        /* Linux returns EAGAIN when an invalid IP packet has been
671        received. We suppress warnings in this case because this might
672        create quite a bit of log traffic on machines with unstable
673        links. (See #60) */
674
675        if (errno != EAGAIN)
676            avahi_log_warn("recvmsg(): %s", strerror(errno));
677
678        goto fail;
679    }
680
681    if (sa.sin_addr.s_addr == INADDR_ANY) {
682        /* Linux 2.4 behaves very strangely sometimes! */
683        goto fail;
684    }
685
686    assert(!(msg.msg_flags & MSG_CTRUNC));
687    assert(!(msg.msg_flags & MSG_TRUNC));
688
689    p->size = (size_t) l;
690
691    if (ret_src_port)
692        *ret_src_port = avahi_port_from_sockaddr((struct sockaddr*) &sa);
693
694    if (ret_src_address) {
695        AvahiAddress a;
696        avahi_address_from_sockaddr((struct sockaddr*) &sa, &a);
697        *ret_src_address = a.data.ipv4;
698    }
699
700    if (ret_ttl)
701        *ret_ttl = 255;
702
703    if (ret_iface)
704        *ret_iface = AVAHI_IF_UNSPEC;
705
706    for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
707
708        if (cmsg->cmsg_level == IPPROTO_IP) {
709
710            switch (cmsg->cmsg_type) {
711#ifdef IP_RECVTTL
712                case IP_RECVTTL:
713#endif
714                case IP_TTL:
715                    if (ret_ttl)
716                        *ret_ttl = (uint8_t) (*(int *) CMSG_DATA(cmsg));
717
718                    break;
719
720#ifdef IP_PKTINFO
721                case IP_PKTINFO: {
722                    struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
723
724                    if (ret_iface)
725                        *ret_iface = (int) i->ipi_ifindex;
726
727                    if (ret_dst_address)
728                        ret_dst_address->address = i->ipi_addr.s_addr;
729
730                    found_addr = 1;
731
732                    break;
733                }
734#endif
735
736#ifdef IP_RECVIF
737                case IP_RECVIF: {
738                    struct sockaddr_dl *sdl = (struct sockaddr_dl *) CMSG_DATA (cmsg);
739
740                    if (ret_iface)
741#ifdef __sun
742                        *ret_iface = *(uint_t*) sdl;
743#else
744                        *ret_iface = (int) sdl->sdl_index;
745#endif
746
747                    break;
748                }
749#endif
750
751#ifdef IP_RECVDSTADDR
752                case IP_RECVDSTADDR:
753                    if (ret_dst_address)
754                        memcpy(&ret_dst_address->address, CMSG_DATA (cmsg), 4);
755
756                    found_addr = 1;
757                    break;
758#endif
759
760                default:
761                    avahi_log_warn("Unhandled cmsg_type : %d", cmsg->cmsg_type);
762                    break;
763            }
764        }
765    }
766
767    assert(found_addr);
768
769    return p;
770
771fail:
772    if (p)
773        avahi_dns_packet_free(p);
774
775    return NULL;
776}
777
778AvahiDnsPacket *avahi_recv_dns_packet_ipv6(
779        int fd,
780        AvahiIPv6Address *ret_src_address,
781        uint16_t *ret_src_port,
782        AvahiIPv6Address *ret_dst_address,
783        AvahiIfIndex *ret_iface,
784        uint8_t *ret_ttl) {
785
786    AvahiDnsPacket *p = NULL;
787    struct msghdr msg;
788    struct iovec io;
789    size_t aux[1024 / sizeof(size_t)];
790    ssize_t l;
791    int ms;
792    struct cmsghdr *cmsg;
793    int found_ttl = 0, found_iface = 0;
794    struct sockaddr_in6 sa;
795
796    assert(fd >= 0);
797
798    if (ioctl(fd, FIONREAD, &ms) < 0) {
799        avahi_log_warn("ioctl(): %s", strerror(errno));
800        goto fail;
801    }
802
803    if (ms < 0) {
804        avahi_log_warn("FIONREAD returned negative value.");
805        goto fail;
806    }
807
808    p = avahi_dns_packet_new(ms + AVAHI_DNS_PACKET_EXTRA_SIZE);
809
810    io.iov_base = AVAHI_DNS_PACKET_DATA(p);
811    io.iov_len = p->max_size;
812
813    memset(&msg, 0, sizeof(msg));
814    msg.msg_name = (struct sockaddr*) &sa;
815    msg.msg_namelen = sizeof(sa);
816
817    msg.msg_iov = &io;
818    msg.msg_iovlen = 1;
819    msg.msg_control = aux;
820    msg.msg_controllen = sizeof(aux);
821    msg.msg_flags = 0;
822
823    if ((l = recvmsg(fd, &msg, 0)) < 0) {
824        /* Linux returns EAGAIN when an invalid IP packet has been
825        received. We suppress warnings in this case because this might
826        create quite a bit of log traffic on machines with unstable
827        links. (See #60) */
828
829        if (errno != EAGAIN)
830            avahi_log_warn("recvmsg(): %s", strerror(errno));
831
832        goto fail;
833    }
834
835    assert(!(msg.msg_flags & MSG_CTRUNC));
836    assert(!(msg.msg_flags & MSG_TRUNC));
837
838    p->size = (size_t) l;
839
840    if (ret_src_port)
841        *ret_src_port = avahi_port_from_sockaddr((struct sockaddr*) &sa);
842
843    if (ret_src_address) {
844        AvahiAddress a;
845        avahi_address_from_sockaddr((struct sockaddr*) &sa, &a);
846        *ret_src_address = a.data.ipv6;
847    }
848
849    for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
850
851        if (cmsg->cmsg_level == IPPROTO_IPV6) {
852
853            switch (cmsg->cmsg_type) {
854
855                case IPV6_HOPLIMIT:
856
857                    if (ret_ttl)
858                        *ret_ttl = (uint8_t) (*(int *) CMSG_DATA(cmsg));
859
860                    found_ttl = 1;
861
862                    break;
863
864                case IPV6_PKTINFO: {
865                    struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
866
867                    if (ret_iface)
868                        *ret_iface = i->ipi6_ifindex;
869
870                    if (ret_dst_address)
871                        memcpy(ret_dst_address->address, i->ipi6_addr.s6_addr, 16);
872
873                    found_iface = 1;
874                    break;
875                }
876
877                default:
878                    avahi_log_warn("Unhandled cmsg_type : %d", cmsg->cmsg_type);
879                    break;
880            }
881        }
882    }
883
884    assert(found_iface);
885    assert(found_ttl);
886
887    return p;
888
889fail:
890    if (p)
891        avahi_dns_packet_free(p);
892
893    return NULL;
894}
895
896int avahi_open_unicast_socket_ipv4(void) {
897    struct sockaddr_in local;
898    int fd = -1;
899
900    if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
901        avahi_log_warn("socket() failed: %s", strerror(errno));
902        goto fail;
903    }
904
905    memset(&local, 0, sizeof(local));
906    local.sin_family = AF_INET;
907
908    if (bind(fd, (struct sockaddr*) &local, sizeof(local)) < 0) {
909        avahi_log_warn("bind() failed: %s", strerror(errno));
910        goto fail;
911    }
912
913    if (ipv4_pktinfo(fd) < 0) {
914         goto fail;
915    }
916
917    if (avahi_set_cloexec(fd) < 0) {
918        avahi_log_warn("FD_CLOEXEC failed: %s", strerror(errno));
919        goto fail;
920    }
921
922    if (avahi_set_nonblock(fd) < 0) {
923        avahi_log_warn("O_NONBLOCK failed: %s", strerror(errno));
924        goto fail;
925    }
926
927    return fd;
928
929fail:
930    if (fd >= 0)
931        close(fd);
932
933    return -1;
934}
935
936int avahi_open_unicast_socket_ipv6(void) {
937    struct sockaddr_in6 local;
938    int fd = -1, yes;
939
940    if ((fd = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
941        avahi_log_warn("socket() failed: %s", strerror(errno));
942        goto fail;
943    }
944
945    yes = 1;
946    if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &yes, sizeof(yes)) < 0) {
947        avahi_log_warn("IPV6_V6ONLY failed: %s", strerror(errno));
948        goto fail;
949    }
950
951    memset(&local, 0, sizeof(local));
952    local.sin6_family = AF_INET6;
953
954    if (bind(fd, (struct sockaddr*) &local, sizeof(local)) < 0) {
955        avahi_log_warn("bind() failed: %s", strerror(errno));
956        goto fail;
957    }
958
959    if (ipv6_pktinfo(fd) < 0)
960        goto fail;
961
962    if (avahi_set_cloexec(fd) < 0) {
963        avahi_log_warn("FD_CLOEXEC failed: %s", strerror(errno));
964        goto fail;
965    }
966
967    if (avahi_set_nonblock(fd) < 0) {
968        avahi_log_warn("O_NONBLOCK failed: %s", strerror(errno));
969        goto fail;
970    }
971
972    return fd;
973
974fail:
975    if (fd >= 0)
976        close(fd);
977
978    return -1;
979}
980