static void avahi_prepare_llmnr_query_job_packet(AvahiLLMNRQueryJob *qj) { assert(qj); /* New Packet*/ qj->p = avahi_llmnr_packet_new_query(512 + AVAHI_DNS_PACKET_EXTRA_SIZE); /* Set ID*/ avahi_dns_packet_set_field(qj->p, AVAHI_LLMNR_FIELD_ID, (uint16_t)(qj->lq->id)); /*Append Key*/ if(!avahi_llmnr_packet_append_key(qj->p, qj->lq->key)) return; /* Set QDCOUNT */ avahi_dns_packet_set_field(qj->p, AVAHI_LLMNR_FIELD_QDCOUNT, 1); }
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 elapse_callback(AVAHI_GCC_UNUSED AvahiTimeEvent *e, void* data) { AvahiQueryJob *qj = data; AvahiQueryScheduler *s; AvahiDnsPacket *p; unsigned n; int b; assert(qj); s = qj->scheduler; if (qj->done) { /* Lets remove it from the history */ job_free(s, qj); return; } assert(!s->known_answers); if (!(p = avahi_dns_packet_new_query(s->interface->hardware->mtu))) return; /* OOM */ b = packet_add_query_job(s, p, qj); assert(b); /* An query must always fit in */ n = 1; /* Try to fill up packet with more queries, if available */ while (s->jobs) { if (!packet_add_query_job(s, p, s->jobs)) break; n++; } avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n); /* Now add known answers */ append_known_answers_and_send(s, 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; }
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); }