+
+
+
+#ifdef SUPPORT_DANE
+/* Lookup TLSA record for host/port.
+Return: OK success with dnssec; DANE mode
+ DEFER Do not use this host now, may retry later
+ FAIL_FORCED No TLSA record; DANE not usable
+ FAIL Do not use this connection
+*/
+
+int
+tlsa_lookup(const host_item * host, dns_answer * dnsa, BOOL dane_required)
+{
+uschar buffer[300];
+const uschar * fullname = buffer;
+int rc;
+BOOL sec;
+
+/* TLSA lookup string */
+(void)sprintf(CS buffer, "_%d._tcp.%.256s", host->port, host->name);
+
+rc = dns_lookup_timerwrap(dnsa, buffer, T_TLSA, &fullname);
+sec = dns_is_secure(dnsa);
+DEBUG(D_transport)
+ debug_printf("TLSA lookup ret %d %sDNSSEC\n", rc, sec ? "" : "not ");
+
+switch (rc)
+ {
+ case DNS_AGAIN:
+ return DEFER; /* just defer this TLS'd conn */
+
+ case DNS_SUCCEED:
+ if (sec)
+ {
+ DEBUG(D_transport)
+ {
+ dns_scan dnss;
+ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
+ rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
+ if (rr->type == T_TLSA && rr->size > 3)
+ {
+ uint16_t payload_length = rr->size - 3;
+ uschar s[MAX_TLSA_EXPANDED_SIZE], * sp = s, * p = US rr->data;
+
+ sp += sprintf(CS sp, "%d ", *p++); /* usage */
+ sp += sprintf(CS sp, "%d ", *p++); /* selector */
+ sp += sprintf(CS sp, "%d ", *p++); /* matchtype */
+ while (payload_length-- > 0 && sp-s < (MAX_TLSA_EXPANDED_SIZE - 4))
+ sp += sprintf(CS sp, "%02x", *p++);
+
+ debug_printf(" %s\n", s);
+ }
+ }
+ return OK;
+ }
+ log_write(0, LOG_MAIN,
+ "DANE error: TLSA lookup for %s not DNSSEC", host->name);
+ /*FALLTRHOUGH*/
+
+ case DNS_NODATA: /* no TLSA RR for this lookup */
+ case DNS_NOMATCH: /* no records at all for this lookup */
+ return dane_required ? FAIL : FAIL_FORCED;
+
+ default:
+ case DNS_FAIL:
+ return dane_required ? FAIL : DEFER;
+ }
+}
+#endif /*SUPPORT_DANE*/
+
+
+
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