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); }