static void lookup_destroy(AvahiWideAreaLookup *l) {
AvahiWideAreaLookup *t;
assert(l);
lookup_stop(l);
t = avahi_hashmap_lookup(l->engine->lookups_by_key, l->key);
AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, by_key, t, l);
if (t)
avahi_hashmap_replace(l->engine->lookups_by_key, avahi_key_ref(l->key), t);
else
avahi_hashmap_remove(l->engine->lookups_by_key, l->key);
AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, lookups, l->engine->lookups, l);
avahi_hashmap_remove(l->engine->lookups_by_id, &l->id);
avahi_dns_packet_free(l->packet);
if (l->key)
avahi_key_unref(l->key);
if (l->cname_key)
avahi_key_unref(l->cname_key);
avahi_free(l);
}
static void send_response_packet(AvahiResponseScheduler *s, AvahiResponseJob *rj) {
AvahiDnsPacket *p;
unsigned n;
assert(s);
assert(rj);
if (!(p = avahi_dns_packet_new_response(s->interface->hardware->mtu, 1)))
return; /* OOM */
n = 1;
/* Put it in the packet. */
if (packet_add_response_job(s, p, rj)) {
/* Try to fill up packet with more responses, if available */
while (s->jobs) {
if (!packet_add_response_job(s, p, s->jobs))
break;
n++;
}
} else {
size_t size;
avahi_dns_packet_free(p);
/* OK, the packet was too small, so create one that fits */
size = avahi_record_get_estimate_size(rj->record) + AVAHI_DNS_PACKET_HEADER_SIZE;
if (!(p = avahi_dns_packet_new_response(size + AVAHI_DNS_PACKET_EXTRA_SIZE, 1)))
return; /* OOM */
if (!packet_add_response_job(s, p, rj)) {
avahi_dns_packet_free(p);
avahi_log_warn("Record too large, cannot send");
job_mark_done(s, rj);
return;
}
}
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n);
avahi_interface_send_packet(s->interface, p, AVAHI_MDNS);
avahi_dns_packet_free(p);
}
static void append_known_answers_and_send(AvahiQueryScheduler *s, AvahiDnsPacket *p) {
AvahiKnownAnswer *ka;
unsigned n;
assert(s);
assert(p);
n = 0;
while ((ka = s->known_answers)) {
int too_large = 0;
while (!avahi_dns_packet_append_record(p, ka->record, 0, 0)) {
if (avahi_dns_packet_is_empty(p)) {
/* The record is too large to fit into one packet, so
there's no point in sending it. Better is letting
the owner of the record send it as a response. This
has the advantage of a cache refresh. */
too_large = 1;
break;
}
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) | AVAHI_DNS_FLAG_TC);
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n);
avahi_interface_send_packet(s->interface, p, AVAHI_MDNS);
avahi_dns_packet_free(p);
p = avahi_dns_packet_new_query(s->interface->hardware->mtu);
n = 0;
}
AVAHI_LLIST_REMOVE(AvahiKnownAnswer, known_answer, s->known_answers, ka);
avahi_record_unref(ka->record);
avahi_free(ka);
if (!too_large)
n++;
}
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n);
avahi_interface_send_packet(s->interface, p, AVAHI_MDNS);
avahi_dns_packet_free(p);
}
static void socket_event(AVAHI_GCC_UNUSED AvahiWatch *w, int fd, AVAHI_GCC_UNUSED AvahiWatchEvent events, void *userdata) {
AvahiWideAreaLookupEngine *e = userdata;
AvahiDnsPacket *p = NULL;
if (fd == e->fd_ipv4)
p = avahi_recv_dns_packet_ipv4(e->fd_ipv4, NULL, NULL, NULL, NULL, NULL);
else {
assert(fd == e->fd_ipv6);
p = avahi_recv_dns_packet_ipv6(e->fd_ipv6, NULL, NULL, NULL, NULL, NULL);
}
if (p) {
handle_packet(e, p);
avahi_dns_packet_free(p);
}
}
void avahi_llmnr_query_job_destroy(AvahiLLMNRQueryScheduler *s, AvahiLLMNRQueryJob *qj) {
assert(s);
assert(qj);
/* Free lq */
avahi_llmnr_query_destroy(qj->lq);
/* Free dns packet and time_event */
if (qj->p)
avahi_dns_packet_free(qj->p);
if(qj->time_event)
avahi_time_event_free(qj->time_event);
/* Remove from the lists */
AVAHI_LLIST_REMOVE(AvahiLLMNRQueryJob, jobs_by_scheduler, s->jobs, qj);
AVAHI_LLIST_REMOVE(AvahiLLMNRQueryJob, jobs_by_interface, s->i->llmnr.queryjobs, qj);
avahi_free(qj);
}
AvahiWideAreaLookup *avahi_wide_area_lookup_new(
AvahiWideAreaLookupEngine *e,
AvahiKey *key,
AvahiWideAreaLookupCallback callback,
void *userdata) {
struct timeval tv;
AvahiWideAreaLookup *l, *t;
uint8_t *p;
assert(e);
assert(key);
assert(callback);
assert(userdata);
l = avahi_new(AvahiWideAreaLookup, 1);
l->engine = e;
l->dead = 0;
l->key = avahi_key_ref(key);
l->cname_key = avahi_key_new_cname(l->key);
l->callback = callback;
l->userdata = userdata;
/* If more than 65K wide area quries are issued simultaneously,
* this will break. This should be limited by some higher level */
for (;; e->next_id++)
if (!find_lookup(e, e->next_id))
break; /* This ID is not yet used. */
l->id = e->next_id++;
/* We keep the packet around in case we need to repeat our query */
l->packet = avahi_dns_packet_new(0);
avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_ID, (uint16_t) l->id);
avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 1, 0, 0, 0, 0, 0));
p = avahi_dns_packet_append_key(l->packet, key, 0);
assert(p);
avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_QDCOUNT, 1);
if (send_to_dns_server(l, l->packet) < 0) {
avahi_log_error(__FILE__": Failed to send packet.");
avahi_dns_packet_free(l->packet);
avahi_key_unref(l->key);
if (l->cname_key)
avahi_key_unref(l->cname_key);
avahi_free(l);
return NULL;
}
l->n_send = 1;
l->time_event = avahi_time_event_new(e->server->time_event_queue, avahi_elapse_time(&tv, 500, 0), sender_timeout_callback, l);
avahi_hashmap_insert(e->lookups_by_id, &l->id, l);
t = avahi_hashmap_lookup(e->lookups_by_key, l->key);
AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, by_key, t, l);
avahi_hashmap_replace(e->lookups_by_key, avahi_key_ref(l->key), t);
AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, lookups, e->lookups, l);
return l;
}
static void elapse_callback(AVAHI_GCC_UNUSED AvahiTimeEvent *e, void* data) {
AvahiProbeJob *pj = data, *next;
AvahiProbeScheduler *s;
AvahiDnsPacket *p;
unsigned n;
assert(pj);
s = pj->scheduler;
if (pj->done) {
/* Lets remove it from the history */
job_free(s, pj);
return;
}
if (!(p = avahi_dns_packet_new_query(s->interface->hardware->mtu)))
return; /* OOM */
n = 1;
/* Add the import probe */
if (!packet_add_probe_query(s, p, pj)) {
size_t size;
AvahiKey *k;
int b;
avahi_dns_packet_free(p);
/* The probe didn't fit in the package, so let's allocate a larger one */
size =
avahi_key_get_estimate_size(pj->record->key) +
avahi_record_get_estimate_size(pj->record) +
AVAHI_DNS_PACKET_HEADER_SIZE;
if (size > AVAHI_DNS_PACKET_SIZE_MAX)
size = AVAHI_DNS_PACKET_SIZE_MAX;
if (!(p = avahi_dns_packet_new_query(size)))
return; /* OOM */
if (!(k = avahi_key_new(pj->record->key->name, pj->record->key->clazz, AVAHI_DNS_TYPE_ANY))) {
avahi_dns_packet_free(p);
return; /* OOM */
}
b = avahi_dns_packet_append_key(p, k, 0) && avahi_dns_packet_append_record(p, pj->record, 0, 0);
avahi_key_unref(k);
if (b) {
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, 1);
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, 1);
avahi_interface_send_packet(s->interface, p);
} else
avahi_log_warn("Probe record too large, cannot send");
avahi_dns_packet_free(p);
job_mark_done(s, pj);
return;
}
/* Try to fill up packet with more probes, if available */
for (pj = s->jobs; pj; pj = pj->jobs_next) {
if (pj->chosen)
continue;
if (!packet_add_probe_query(s, p, pj))
break;
n++;
}
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n);
n = 0;
/* Now add the chosen records to the authorative section */
for (pj = s->jobs; pj; pj = next) {
next = pj->jobs_next;
if (!pj->chosen)
continue;
if (!avahi_dns_packet_append_record(p, pj->record, 0, 0)) {
/* avahi_log_warn("Bad probe size estimate!"); */
/* Unmark all following jobs */
for (; pj; pj = pj->jobs_next)
pj->chosen = 0;
break;
}
job_mark_done(s, pj);
n ++;
}
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, n);
/* Send it now */
avahi_interface_send_packet(s->interface, p);
avahi_dns_packet_free(p);
}
int main(AVAHI_GCC_UNUSED int argc, AVAHI_GCC_UNUSED char *argv[]) {
char t[AVAHI_DOMAIN_NAME_MAX], *m;
const char *a, *b, *c, *d;
AvahiDnsPacket *p;
AvahiRecord *r, *r2;
uint8_t rdata[AVAHI_DNS_RDATA_MAX];
size_t l;
p = avahi_dns_packet_new(0);
assert(avahi_dns_packet_append_name(p, a = "Ahello.hello.hello.de."));
assert(avahi_dns_packet_append_name(p, b = "Bthis is a test.hello.de."));
assert(avahi_dns_packet_append_name(p, c = "Cthis\\.is\\.a\\.test\\.with\\.dots.hello.de."));
assert(avahi_dns_packet_append_name(p, d = "Dthis\\\\is another test.hello.de."));
avahi_hexdump(AVAHI_DNS_PACKET_DATA(p), p->size);
assert(avahi_dns_packet_consume_name(p, t, sizeof(t)) == 0);
avahi_log_debug(">%s<", t);
assert(avahi_domain_equal(a, t));
assert(avahi_dns_packet_consume_name(p, t, sizeof(t)) == 0);
avahi_log_debug(">%s<", t);
assert(avahi_domain_equal(b, t));
assert(avahi_dns_packet_consume_name(p, t, sizeof(t)) == 0);
avahi_log_debug(">%s<", t);
assert(avahi_domain_equal(c, t));
assert(avahi_dns_packet_consume_name(p, t, sizeof(t)) == 0);
avahi_log_debug(">%s<", t);
assert(avahi_domain_equal(d, t));
avahi_dns_packet_free(p);
/* RDATA PARSING AND SERIALIZATION */
/* Create an AvahiRecord with some usful data */
r = avahi_record_new_full("foobar.local", AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_HINFO, AVAHI_DEFAULT_TTL);
assert(r);
r->data.hinfo.cpu = avahi_strdup("FOO");
r->data.hinfo.os = avahi_strdup("BAR");
/* Serialize it into a blob */
assert((l = avahi_rdata_serialize(r, rdata, sizeof(rdata))) != (size_t) -1);
/* Print it */
avahi_hexdump(rdata, l);
/* Create a new record and fill in the data from the blob */
r2 = avahi_record_new(r->key, AVAHI_DEFAULT_TTL);
assert(r2);
assert(avahi_rdata_parse(r2, rdata, l) >= 0);
/* Compare both versions */
assert(avahi_record_equal_no_ttl(r, r2));
/* Free the records */
avahi_record_unref(r);
avahi_record_unref(r2);
r = avahi_record_new_full("foobar", 77, 77, AVAHI_DEFAULT_TTL);
assert(r);
assert(r->data.generic.data = avahi_memdup("HALLO", r->data.generic.size = 5));
m = avahi_record_to_string(r);
assert(m);
avahi_log_debug(">%s<", m);
avahi_free(m);
avahi_record_unref(r);
return 0;
}
AvahiDnsPacket *avahi_recv_dns_packet_ipv6(
int fd,
AvahiIPv6Address *ret_src_address,
uint16_t *ret_src_port,
AvahiIPv6Address *ret_dst_address,
AvahiIfIndex *ret_iface,
uint8_t *ret_ttl) {
AvahiDnsPacket *p = NULL;
struct msghdr msg;
struct iovec io;
size_t aux[1024 / sizeof(size_t)];
ssize_t l;
int ms;
struct cmsghdr *cmsg;
int found_ttl = 0, found_iface = 0;
struct sockaddr_in6 sa;
assert(fd >= 0);
if (ioctl(fd, FIONREAD, &ms) < 0) {
avahi_log_warn("ioctl(): %s", strerror(errno));
goto fail;
}
if (ms < 0) {
avahi_log_warn("FIONREAD returned negative value.");
goto fail;
}
p = avahi_dns_packet_new(ms + AVAHI_DNS_PACKET_EXTRA_SIZE);
io.iov_base = AVAHI_DNS_PACKET_DATA(p);
io.iov_len = p->max_size;
memset(&msg, 0, sizeof(msg));
msg.msg_name = (struct sockaddr*) &sa;
msg.msg_namelen = sizeof(sa);
msg.msg_iov = &io;
msg.msg_iovlen = 1;
msg.msg_control = aux;
msg.msg_controllen = sizeof(aux);
msg.msg_flags = 0;
if ((l = recvmsg(fd, &msg, 0)) < 0) {
/* Linux returns EAGAIN when an invalid IP packet has been
received. We suppress warnings in this case because this might
create quite a bit of log traffic on machines with unstable
links. (See #60) */
if (errno != EAGAIN)
avahi_log_warn("recvmsg(): %s", strerror(errno));
goto fail;
}
assert(!(msg.msg_flags & MSG_CTRUNC));
assert(!(msg.msg_flags & MSG_TRUNC));
p->size = (size_t) l;
if (ret_src_port)
*ret_src_port = avahi_port_from_sockaddr((struct sockaddr*) &sa);
if (ret_src_address) {
AvahiAddress a;
avahi_address_from_sockaddr((struct sockaddr*) &sa, &a);
*ret_src_address = a.data.ipv6;
}
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == IPPROTO_IPV6) {
switch (cmsg->cmsg_type) {
case IPV6_HOPLIMIT:
if (ret_ttl)
*ret_ttl = (uint8_t) (*(int *) CMSG_DATA(cmsg));
found_ttl = 1;
break;
case IPV6_PKTINFO: {
struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
if (ret_iface)
*ret_iface = i->ipi6_ifindex;
if (ret_dst_address)
memcpy(ret_dst_address->address, i->ipi6_addr.s6_addr, 16);
found_iface = 1;
break;
}
default:
avahi_log_warn("Unhandled cmsg_type : %d", cmsg->cmsg_type);
break;
}
}
}
assert(found_iface);
assert(found_ttl);
return p;
fail:
if (p)
avahi_dns_packet_free(p);
return NULL;
}
AvahiDnsPacket *avahi_recv_dns_packet_ipv4(
int fd,
AvahiIPv4Address *ret_src_address,
uint16_t *ret_src_port,
AvahiIPv4Address *ret_dst_address,
AvahiIfIndex *ret_iface,
uint8_t *ret_ttl) {
AvahiDnsPacket *p= NULL;
struct msghdr msg;
struct iovec io;
size_t aux[1024 / sizeof(size_t)]; /* for alignment on ia64 ! */
ssize_t l;
struct cmsghdr *cmsg;
int found_addr = 0;
int ms;
struct sockaddr_in sa;
assert(fd >= 0);
if (ioctl(fd, FIONREAD, &ms) < 0) {
avahi_log_warn("ioctl(): %s", strerror(errno));
goto fail;
}
if (ms < 0) {
avahi_log_warn("FIONREAD returned negative value.");
goto fail;
}
p = avahi_dns_packet_new(ms + AVAHI_DNS_PACKET_EXTRA_SIZE);
io.iov_base = AVAHI_DNS_PACKET_DATA(p);
io.iov_len = p->max_size;
memset(&msg, 0, sizeof(msg));
msg.msg_name = &sa;
msg.msg_namelen = sizeof(sa);
msg.msg_iov = &io;
msg.msg_iovlen = 1;
msg.msg_control = aux;
msg.msg_controllen = sizeof(aux);
msg.msg_flags = 0;
if ((l = recvmsg(fd, &msg, 0)) < 0) {
/* Linux returns EAGAIN when an invalid IP packet has been
received. We suppress warnings in this case because this might
create quite a bit of log traffic on machines with unstable
links. (See #60) */
if (errno != EAGAIN)
avahi_log_warn("recvmsg(): %s", strerror(errno));
goto fail;
}
if (sa.sin_addr.s_addr == INADDR_ANY) {
/* Linux 2.4 behaves very strangely sometimes! */
goto fail;
}
assert(!(msg.msg_flags & MSG_CTRUNC));
assert(!(msg.msg_flags & MSG_TRUNC));
p->size = (size_t) l;
if (ret_src_port)
*ret_src_port = avahi_port_from_sockaddr((struct sockaddr*) &sa);
if (ret_src_address) {
AvahiAddress a;
avahi_address_from_sockaddr((struct sockaddr*) &sa, &a);
*ret_src_address = a.data.ipv4;
}
if (ret_ttl)
*ret_ttl = 255;
if (ret_iface)
*ret_iface = AVAHI_IF_UNSPEC;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == IPPROTO_IP) {
switch (cmsg->cmsg_type) {
#ifdef IP_RECVTTL
case IP_RECVTTL:
#endif
case IP_TTL:
if (ret_ttl)
*ret_ttl = (uint8_t) (*(int *) CMSG_DATA(cmsg));
break;
#ifdef IP_PKTINFO
case IP_PKTINFO: {
struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
if (ret_iface)
*ret_iface = (int) i->ipi_ifindex;
if (ret_dst_address)
ret_dst_address->address = i->ipi_addr.s_addr;
found_addr = 1;
break;
}
#endif
#ifdef IP_RECVIF
case IP_RECVIF: {
struct sockaddr_dl *sdl = (struct sockaddr_dl *) CMSG_DATA (cmsg);
if (ret_iface)
#ifdef __sun
*ret_iface = *(uint_t*) sdl;
#else
*ret_iface = (int) sdl->sdl_index;
#endif
break;
}
#endif
#ifdef IP_RECVDSTADDR
case IP_RECVDSTADDR:
if (ret_dst_address)
memcpy(&ret_dst_address->address, CMSG_DATA (cmsg), 4);
found_addr = 1;
break;
#endif
default:
avahi_log_warn("Unhandled cmsg_type : %d", cmsg->cmsg_type);
break;
}
}
}
assert(found_addr);
return p;
fail:
if (p)
avahi_dns_packet_free(p);
return NULL;
}
