static int query(struct dns_query **qp, struct dnsc *dnsc, uint8_t opcode, const char *name, uint16_t type, uint16_t dnsclass, const struct dnsrr *ans_rr, int proto, const struct sa *srvv, const uint32_t *srvc, bool aa, bool rd, dns_query_h *qh, void *arg) { struct dns_query *q = NULL; struct dnshdr hdr; int err = 0; uint32_t i; if (!dnsc || !name || !srvv || !srvc || !(*srvc)) return EINVAL; if (DNS_QTYPE_AXFR == type) proto = IPPROTO_TCP; q = mem_zalloc(sizeof(*q), query_destructor); if (!q) goto nmerr; hash_append(dnsc->ht_query, hash_joaat_str_ci(name), &q->le, q); tmr_init(&q->tmr); mbuf_init(&q->mb); for (i=0; i<ARRAY_SIZE(q->rrlv); i++) list_init(&q->rrlv[i]); err = str_dup(&q->name, name); if (err) goto error; q->srvv = srvv; q->srvc = srvc; q->id = rand_u16(); q->type = type; q->opcode = opcode; q->dnsclass = dnsclass; q->dnsc = dnsc; memset(&hdr, 0, sizeof(hdr)); hdr.id = q->id; hdr.opcode = q->opcode; hdr.aa = aa; hdr.rd = rd; hdr.nq = 1; hdr.nans = ans_rr ? 1 : 0; if (proto == IPPROTO_TCP) q->mb.pos += 2; err = dns_hdr_encode(&q->mb, &hdr); if (err) goto error; err = dns_dname_encode(&q->mb, name, NULL, 0, false); if (err) goto error; err |= mbuf_write_u16(&q->mb, htons(type)); err |= mbuf_write_u16(&q->mb, htons(dnsclass)); if (err) goto error; if (ans_rr) { err = dns_rr_encode(&q->mb, ans_rr, 0, NULL, 0); if (err) goto error; } q->qh = qh; q->arg = arg; switch (proto) { case IPPROTO_TCP: q->mb.pos = 0; (void)mbuf_write_u16(&q->mb, htons(q->mb.end - 2)); err = send_tcp(q); if (err) goto error; tmr_start(&q->tmr, 60 * 1000, tcp_timeout_handler, q); break; case IPPROTO_UDP: err = send_udp(q); if (err) goto error; tmr_start(&q->tmr, 500, udp_timeout_handler, q); break; default: err = EPROTONOSUPPORT; goto error; } if (qp) { q->qp = qp; *qp = q; } return 0; nmerr: err = ENOMEM; error: mem_deref(q); return err; }
static void decode_dns_query(struct dns_server *srv, const struct sa *src, struct mbuf *mb) { struct list rrl = LIST_INIT; struct dnshdr hdr; struct le *le; char *qname = NULL; size_t start, end; uint16_t type, dnsclass; int err = 0; start = mb->pos; end = mb->end; if (dns_hdr_decode(mb, &hdr) || hdr.qr || hdr.nq != 1) { DEBUG_WARNING("unable to decode query header\n"); return; } err = dns_dname_decode(mb, &qname, start); if (err) { DEBUG_WARNING("unable to decode query name\n"); goto out; } if (mbuf_get_left(mb) < 4) { err = EBADMSG; DEBUG_WARNING("unable to decode query type/class\n"); goto out; } type = ntohs(mbuf_read_u16(mb)); dnsclass = ntohs(mbuf_read_u16(mb)); DEBUG_INFO("dnssrv: type=%s query-name='%s'\n", dns_rr_typename(type), qname); if (dnsclass == DNS_CLASS_IN) { dns_server_match(srv, &rrl, qname, type); } hdr.qr = true; hdr.tc = false; hdr.rcode = DNS_RCODE_OK; hdr.nq = 1; hdr.nans = list_count(&rrl); mb->pos = start; err = dns_hdr_encode(mb, &hdr); if (err) goto out; mb->pos = end; DEBUG_INFO("dnssrv: @@ found %u answers for %s\n", list_count(&rrl), qname); for (le = rrl.head; le; le = le->next) { struct dnsrr *rr = le->data; err = dns_rr_encode(mb, rr, 0, NULL, start); if (err) goto out; } mb->pos = start; (void)udp_send(srv->us, src, mb); out: list_clear(&rrl); mem_deref(qname); }