void callback(void *cbarg, int r, const struct rr_entry *entry)
{
struct mdns_ctx *ctx = (struct mdns_ctx *) cbarg;
struct mdns_hdr hdr = {0};
struct rr_entry answer = {0};
hdr.flags |= FLAG_QR;
hdr.flags |= FLAG_AA;
hdr.num_ans_rr = 1;
answer.name = entry->name;
answer.type = entry->type;
answer.rr_class = entry->rr_class;
answer.ttl = 120;
sprintf(answer.data.A.addr_str, "192.168.1.1");
inet_pton(AF_INET, answer.data.A.addr_str, &answer.data.A.addr);
mdns_entries_send(ctx, &hdr, &answer);
}
int
mdns_listen(const struct mdns_ctx *ctx, const char *const names[],
unsigned int nb_names, enum rr_type type, unsigned int interval,
mdns_stop_func stop, mdns_callback callback, void *p_cookie)
{
int r;
time_t t1, t2;
struct mdns_hdr hdr = {0};
struct rr_entry *qns = malloc(nb_names * sizeof(struct rr_entry));
if (qns == NULL)
return (MDNS_STDERR);
memset(qns, 0, nb_names * sizeof(struct rr_entry));
hdr.num_qn = nb_names;
for (unsigned int i = 0; i < nb_names; ++i)
{
qns[i].name = (char *)names[i];
qns[i].type = type;
qns[i].rr_class = RR_IN;
if (i + 1 < nb_names)
qns[i].next = &qns[i+1];
}
if (setsockopt(ctx->sock, SOL_SOCKET, SO_RCVTIMEO, (const void *) &os_deadline, sizeof(os_deadline)) < 0)
{
free(qns);
return (MDNS_NETERR);
}
if (setsockopt(ctx->sock, SOL_SOCKET, SO_SNDTIMEO, (const void *) &os_deadline, sizeof(os_deadline)) < 0)
{
free(qns);
return (MDNS_NETERR);
}
if ((r = mdns_entries_send(ctx, &hdr, qns)) < 0) // send a first probe request
callback(p_cookie, r, NULL);
for (t1 = t2 = time(NULL); stop(p_cookie) == false; t2 = time(NULL)) {
struct mdns_hdr ahdr = {0};
struct rr_entry *entries;
if (difftime(t2, t1) >= (double) interval) {
if ((r = mdns_entries_send(ctx, &hdr, qns)) < 0) {
callback(p_cookie, r, NULL);
continue;
}
t1 = t2;
}
r = mdns_recv(ctx, &ahdr, &entries);
if (r == MDNS_NETERR && os_wouldblock())
{
mdns_free(entries);
continue;
}
if (ahdr.num_ans_rr + ahdr.num_add_rr == 0)
{
mdns_free(entries);
continue;
}
for (struct rr_entry *entry = entries; entry; entry = entry->next) {
for (unsigned int i = 0; i < nb_names; ++i) {
if (!strrcmp(entry->name, names[i])) {
callback(p_cookie, r, entries);
break;
}
}
}
mdns_free(entries);
}
free(qns);
return (0);
}
