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 (!(p = avahi_dns_packet_new_query(size + AVAHI_DNS_PACKET_EXTRA_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);
}
Пример #2
0
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;
}