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 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 send_conflict_query(AvahiLLMNRQueryJob *qj) {
/* Send the packet */
AvahiRecord *r;
AvahiLLMNRQuery *lq;
assert(qj);
/* We use the same lq */
/*1. Change 'lq->type' and reset 'n_sent' */
lq = qj->lq;
lq->callback(lq->interface->hardware->index, lq->interface->protocol, NULL, lq->userdata);
lq->type = AVAHI_LLMNR_CONFLICT_QUERY;
qj->n_sent = 0;
/* Reset 'c' bit in existing packet */
avahi_dns_packet_set_field(qj->p, AVAHI_LLMNR_FIELD_FLAGS, AVAHI_LLMNR_FLAGS(0, 0, 1, 0, 0, 0, 0));
/* Append records */
while((r = avahi_record_list_next(lq->c_bit_clear, NULL, NULL, NULL))) {
/* Append Record TODO TTL*/
if(!(avahi_llmnr_packet_append_record(qj->p, r, AVAHI_DEFAULT_TTL)))
/* we send only those much of record which fits in */
break;
avahi_dns_packet_inc_field(qj->p, AVAHI_LLMNR_FIELD_ARCOUNT);
}
/* Send packet */
if(avahi_dns_packet_get_field(qj->p, AVAHI_LLMNR_FIELD_ARCOUNT) != 0)
avahi_interface_send_packet(lq->interface, qj->p, AVAHI_LLMNR);
/* Destroy this AvahiLLMNRQueryJob */
avahi_llmnr_query_job_destroy(qj->scheduler, qj);
return;
}
static void resend_llmnr_query(AvahiLLMNRQueryJob *qj) {
AvahiLLMNRQuery *lq = qj->lq;
struct timeval tv;
assert(qj);
if(lq->type == AVAHI_LLMNR_SIMPLE_QUERY || lq->type == AVAHI_LLMNR_UNIQUENESS_VERIFICATION_QUERY) {
/**Check whether we have already sent this query three times */
if(qj->n_sent >= 3) {
lq->callback(lq->interface->hardware->index, lq->interface->protocol, NULL, lq->userdata);
avahi_llmnr_query_job_destroy(qj->scheduler, qj);
/* Free Timeevent */
/* avahi_time_event_free(qj->time_event);
qj->time_event = NULL;*/
} else {
/* Send packet */
avahi_interface_send_packet(lq->interface, qj->p, AVAHI_LLMNR);
(qj->n_sent)++;
/* Schedule further queries*/
avahi_elapse_time(&tv, AVAHI_LLMNR_INTERVAL, 0);
avahi_time_event_update(qj->time_event, &tv);
}
} else {
assert(lq->type == AVAHI_LLMNR_CONFLICT_QUERY);
assert(qj->n_sent == 1);
/* Destroy this query */
lq->callback(lq->interface->hardware->index, lq->interface->protocol, NULL, lq->userdata);
avahi_llmnr_query_job_destroy(qj->scheduler, qj);
}
return;
}
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);
}
