+#ifdef EXPERIMENTAL_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)
+{
+/* move this out to host.c given the similarity to dns_lookup() ? */
+uschar buffer[300];
+const uschar * fullname = buffer;
+
+/* TLSA lookup string */
+(void)sprintf(CS buffer, "_%d._tcp.%.256s", host->port, host->name);
+
+switch (dns_lookup(dnsa, buffer, T_TLSA, &fullname))
+ {
+ case DNS_SUCCEED:
+ if (!dns_is_secure(dnsa))
+ {
+ log_write(0, LOG_MAIN, "DANE error: TLSA lookup not DNSSEC");
+ return DEFER;
+ }
+ return OK;
+
+ case DNS_AGAIN:
+ return DEFER; /* just defer this TLS'd conn */
+
+ case DNS_NOMATCH:
+ return dane_required ? FAIL : FAIL_FORCED;
+
+ default:
+ case DNS_FAIL:
+ return dane_required ? FAIL : DEFER;
+ }
+}
+#endif
+
+
+
+typedef struct smtp_compare_s
+{
+ uschar *current_sender_address;
+ struct transport_instance *tblock;
+} smtp_compare_t;
+
+/*
+Create a unique string that identifies this message, it is based on
+sender_address, helo_data and tls_certificate if enabled. */
+
+static uschar *
+smtp_local_identity(uschar * sender, struct transport_instance * tblock)
+{
+address_item * addr1;
+uschar * if1 = US"";
+uschar * helo1 = US"";
+#ifdef SUPPORT_TLS
+uschar * tlsc1 = US"";
+#endif
+uschar * save_sender_address = sender_address;
+uschar * local_identity = NULL;
+smtp_transport_options_block * ob =
+ (smtp_transport_options_block *)tblock->options_block;
+
+sender_address = sender;
+
+addr1 = deliver_make_addr (sender, TRUE);
+deliver_set_expansions(addr1);
+
+if (ob->interface)
+ if1 = expand_string(ob->interface);
+
+if (ob->helo_data)
+ helo1 = expand_string(ob->helo_data);
+
+#ifdef SUPPORT_TLS
+if (ob->tls_certificate)
+ tlsc1 = expand_string(ob->tls_certificate);
+local_identity = string_sprintf ("%s^%s^%s", if1, helo1, tlsc1);
+#else
+local_identity = string_sprintf ("%s^%s", if1, helo1);
+#endif
+
+deliver_set_expansions(NULL);
+sender_address = save_sender_address;
+
+return local_identity;
+}
+
+
+
+/* This routine is a callback that is called from transport_check_waiting.
+This function will evaluate the incoming message versus the previous
+message. If the incoming message is using a different local identity then
+we will veto this new message. */
+
+static BOOL
+smtp_are_same_identities(uschar * message_id, smtp_compare_t * s_compare)
+{
+uschar * message_local_identity,
+ * current_local_identity,
+ * new_sender_address;
+
+current_local_identity =
+ smtp_local_identity(s_compare->current_sender_address, s_compare->tblock);
+
+if (!(new_sender_address = deliver_get_sender_address(message_id)))
+ return 0;
+
+message_local_identity =
+ smtp_local_identity(new_sender_address, s_compare->tblock);
+
+return Ustrcmp(current_local_identity, message_local_identity) == 0;
+}
+
+
+
+uschar
+ehlo_response(uschar * buf, size_t bsize, uschar checks)
+{
+#ifdef SUPPORT_TLS
+if ( checks & PEER_OFFERED_TLS
+ && pcre_exec(regex_STARTTLS, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+ checks &= ~PEER_OFFERED_TLS;
+#endif
+
+if ( checks & PEER_OFFERED_IGNQ
+ && pcre_exec(regex_IGNOREQUOTA, NULL, CS buf, bsize, 0,
+ PCRE_EOPT, NULL, 0) < 0)
+ checks &= ~PEER_OFFERED_IGNQ;
+
+if ( checks & PEER_OFFERED_CHUNKING
+ && pcre_exec(regex_CHUNKING, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+ checks &= ~PEER_OFFERED_CHUNKING;
+
+#ifndef DISABLE_PRDR
+if ( checks & PEER_OFFERED_PRDR
+ && pcre_exec(regex_PRDR, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+ checks &= ~PEER_OFFERED_PRDR;
+#endif
+
+#ifdef SUPPORT_I18N
+if ( checks & PEER_OFFERED_UTF8
+ && pcre_exec(regex_UTF8, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+ checks &= ~PEER_OFFERED_UTF8;
+#endif
+
+if ( checks & PEER_OFFERED_DSN
+ && pcre_exec(regex_DSN, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+ checks &= ~PEER_OFFERED_DSN;
+
+if ( checks & PEER_OFFERED_PIPE
+ && pcre_exec(regex_PIPELINING, NULL, CS buf, bsize, 0,
+ PCRE_EOPT, NULL, 0) < 0)
+ checks &= ~PEER_OFFERED_PIPE;
+
+if ( checks & PEER_OFFERED_SIZE
+ && pcre_exec(regex_SIZE, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+ checks &= ~PEER_OFFERED_SIZE;
+
+return checks;
+}
+
+
+
+/* Callback for emitting a BDAT data chunk header.
+
+If given a nonzero size, first flush any buffered SMTP commands
+then emit the command.
+
+Reap previous SMTP command responses if requested.
+Reap one SMTP command response if requested.
+
+Returns: OK or ERROR
+*/
+
+static int
+smtp_chunk_cmd_callback(int fd, transport_ctx * tctx,
+ unsigned chunk_size, unsigned flags)
+{
+smtp_transport_options_block * ob =
+ (smtp_transport_options_block *)(tctx->tblock->options_block);
+int cmd_count = 0;
+int prev_cmd_count;
+uschar * buffer = tctx->buffer;
+
+
+/* Write SMTP chunk header command */
+
+if (chunk_size > 0)
+ if((cmd_count = smtp_write_command(tctx->outblock, FALSE, "BDAT %u%s\r\n",
+ chunk_size,
+ flags & tc_chunk_last ? " LAST" : "")
+ ) < 0) return ERROR;
+
+prev_cmd_count = cmd_count += tctx->cmd_count;
+
+/* Reap responses for any previous, but not one we just emitted */
+
+if (chunk_size > 0)
+ prev_cmd_count--;
+if (tctx->pending_BDAT)
+ prev_cmd_count--;
+
+if (flags & tc_reap_prev && prev_cmd_count > 0)
+ {
+
+ switch(sync_responses(tctx->first_addr, tctx->tblock->rcpt_include_affixes,
+ tctx->sync_addr, tctx->host, prev_cmd_count,
+ ob->address_retry_include_sender,
+ tctx->pending_MAIL, 0,
+ tctx->inblock,
+ ob->command_timeout,
+ buffer, 4096))
+/*XXX buffer size! */
+ {
+ case 1: /* 2xx (only) => OK */
+ case 3: tctx->good_RCPT = TRUE; /* 2xx & 5xx => OK & progress made */
+ case 2: *tctx->completed_address = TRUE; /* 5xx (only) => progress made */
+ case 0: break; /* No 2xx or 5xx, but no probs */
+
+ case -1: /* Timeout on RCPT */
+ default: return ERROR; /* I/O error, or any MAIL/DATA error */
+ }
+ cmd_count = 1;
+ if (!tctx->pending_BDAT)
+ pipelining_active = FALSE;
+ }
+
+/* Reap response for the cmd we just emitted, or an outstanding BDAT */
+
+if (flags & tc_reap_one || tctx->pending_BDAT)
+ {
+/*XXX buffer size! */
+ if (!smtp_read_response(tctx->inblock, buffer, 4096, '2',
+ ob->command_timeout))
+ {
+ if (errno == 0 && buffer[0] == '4')
+ {
+ errno = ERRNO_DATA4XX; /*XXX does this actually get used? */
+ tctx->first_addr->more_errno |=
+ ((buffer[1] - '0')*10 + buffer[2] - '0') << 8;
+ }
+ return ERROR;
+ }
+ cmd_count--;
+ tctx->pending_BDAT = FALSE;
+ pipelining_active = FALSE;
+ }
+else if (chunk_size > 0)
+ tctx->pending_BDAT = TRUE;
+
+
+tctx->cmd_count = cmd_count;
+return OK;
+}
+
+
+