PIPE_CONNECT: promote from experimental

16 files changed, 80 insertions, 75 deletions

diff --git a/src/src/EDITME b/src/src/EDITME
index fe945c3fd..fa1fe1c9f 100644
--- a/src/src/EDITME
+++ b/src/src/EDITME
@@ -562,6 +562,11 @@ DISABLE_MAL_MKS=yes
 # DISABLE_EVENT=yes
 
 
+# Uncomment this line to include support for early pipelining, per
+# https://datatracker.ietf.org/doc/draft-harris-early-pipe/
+# SUPPORT_PIPE_CONNECT
+
+
 #------------------------------------------------------------------------------
 # Compiling Exim with experimental features. These are documented in
 # experimental-spec.txt. "Experimental" means that the way these features are
diff --git a/src/src/config.h.defaults b/src/src/config.h.defaults
index 27b8fb409..17239bb85 100644
--- a/src/src/config.h.defaults
+++ b/src/src/config.h.defaults
@@ -149,6 +149,7 @@ Do not put spaces between # and the 'define'.
 #define SUPPORT_MAILSTORE
 #define SUPPORT_MBX
 #define SUPPORT_MOVE_FROZEN_MESSAGES
+#define SUPPORT_PIPE_CONNECT
 #define SUPPORT_PAM
 #define SUPPORT_PROXY
 #define SUPPORT_SOCKS
@@ -201,7 +202,6 @@ Do not put spaces between # and the 'define'.
 #define EXPERIMENTAL_DMARC
 #define DMARC_TLD_FILE "/etc/exim/opendmarc.tlds"
 #define EXPERIMENTAL_LMDB
-#define EXPERIMENTAL_PIPE_CONNECT
 #define EXPERIMENTAL_QUEUEFILE
 #define EXPERIMENTAL_SRS
 #define EXPERIMENTAL_TLS_RESUME
diff --git a/src/src/dbstuff.h b/src/src/dbstuff.h
index 58154d7ef..b7889bd8e 100644
--- a/src/src/dbstuff.h
+++ b/src/src/dbstuff.h
@@ -786,7 +786,7 @@ typedef struct {
   uschar   bloom[40];     /* Bloom filter which may be larger than this */
 } dbdata_ratelimit_unique;
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 /* This structure records the EHLO responses, cleartext and crypted,
 for an IP, as bitmasks (cf. OPTION_TLS) */
 
diff --git a/src/src/deliver.c b/src/src/deliver.c
index dc7a7d5fb..b26e5dbd4 100644
--- a/src/src/deliver.c
+++ b/src/src/deliver.c
@@ -1250,7 +1250,7 @@ else
     {
     if (testflag(addr, af_pipelining))
       g = string_catn(g, US" L", 2);
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     if (testflag(addr, af_early_pipe))
       g = string_catn(g, US"*", 1);
 #endif
@@ -3564,7 +3564,7 @@ while (!done)
     case 'L':
       switch (*subid)
 	{
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	case 2: setflag(addr, af_early_pipe);	/*FALLTHROUGH*/
 #endif
 	case 1: setflag(addr, af_pipelining); break;
@@ -4872,7 +4872,7 @@ all pipes, so I do not see a reason to use non-blocking IO here
 #endif
 
       if (testflag(addr, af_pipelining))
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	if (testflag(addr, af_early_pipe))
 	  rmt_dlv_checked_write(fd, 'L', '2', NULL, 0);
 	else
@@ -8537,7 +8537,7 @@ if (!regex_DSN) regex_DSN  =
 if (!regex_IGNOREQUOTA) regex_IGNOREQUOTA =
   regex_must_compile(US"\\n250[\\s\\-]IGNOREQUOTA(\\s|\\n|$)", FALSE, TRUE);
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 if (!regex_EARLY_PIPE) regex_EARLY_PIPE =
   regex_must_compile(US"\\n250[\\s\\-]" EARLY_PIPE_FEATURE_NAME "(\\s|\\n|$)", FALSE, TRUE);
 #endif
diff --git a/src/src/exim.c b/src/src/exim.c
index abce9fc69..7571705d7 100644
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -890,6 +890,9 @@ fprintf(fp, "Support for:");
 #ifndef DISABLE_OCSP
   fprintf(fp, " OCSP");
 #endif
+#ifdef SUPPORT_PIPE_CONNECT
+  fprintf(fp, " PIPE_CONNECT");
+#endif
 #ifndef DISABLE_PRDR
   fprintf(fp, " PRDR");
 #endif
@@ -930,9 +933,6 @@ fprintf(fp, "Support for:");
 #ifdef EXPERIMENTAL_DSN_INFO
   fprintf(fp, " Experimental_DSN_info");
 #endif
-#ifdef EXPERIMENTAL_PIPE_CONNECT
-  fprintf(fp, " Experimental_PIPE_CONNECT");
-#endif
 #ifdef EXPERIMENTAL_TLS_RESUME
   fprintf(fp, " Experimental_TLS_resume");
 #endif
diff --git a/src/src/globals.c b/src/src/globals.c
index 5ce04a6ed..e70e38538 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -297,7 +297,7 @@ struct global_flags f =
 	.sender_name_forced     = FALSE,
 	.sender_set_untrusted   = FALSE,
 	.smtp_authenticated     = FALSE,
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	.smtp_in_early_pipe_advertised = FALSE,
 	.smtp_in_early_pipe_no_auth = FALSE,
 	.smtp_in_early_pipe_used = FALSE,
@@ -1163,7 +1163,7 @@ uschar *override_pid_file_path = NULL;
 uschar *percent_hack_domains   = NULL;
 uschar *pid_file_path          = US PID_FILE_PATH
                            "\0<--------------Space to patch pid_file_path->";
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 uschar *pipe_connect_advertise_hosts = US"*";
 #endif
 uschar *pipelining_advertise_hosts = US"*";
@@ -1253,7 +1253,7 @@ const pcre *regex_From         = NULL;
 const pcre *regex_IGNOREQUOTA  = NULL;
 const pcre *regex_PIPELINING   = NULL;
 const pcre *regex_SIZE         = NULL;
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 const pcre *regex_EARLY_PIPE   = NULL;
 #endif
 const pcre *regex_ismsgid      = NULL;
diff --git a/src/src/globals.h b/src/src/globals.h
index d29fcc4e1..83d29ba9b 100644
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -257,7 +257,7 @@ extern struct global_flags {
  BOOL   sender_name_forced		:1; /* Set by -F */
  BOOL   sender_set_untrusted		:1; /* Sender set by untrusted caller */
  BOOL   smtp_authenticated		:1; /* Sending client has authenticated */
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
  BOOL   smtp_in_early_pipe_advertised	:1; /* server advertised PIPE_CONNECT */
  BOOL	smtp_in_early_pipe_no_auth	:1; /* too many authenticator names */
  BOOL   smtp_in_early_pipe_used		:1; /* client did send early data */
@@ -746,7 +746,7 @@ extern uschar *override_pid_file_path; /* Value of -oP argument */
 
 extern uschar *percent_hack_domains;   /* Local domains for which '% operates */
 extern uschar *pid_file_path;          /* For writing daemon pids */
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 extern uschar *pipe_connect_advertise_hosts; /* for banner/EHLO pipelining */
 #endif
 extern uschar *pipelining_advertise_hosts; /* As it says */
@@ -828,7 +828,7 @@ extern const pcre  *regex_CHUNKING;    /* For recognizing CHUNKING (RFC 3030) */
 extern const pcre  *regex_IGNOREQUOTA; /* For recognizing IGNOREQUOTA (LMTP) */
 extern const pcre  *regex_PIPELINING;  /* For recognizing PIPELINING */
 extern const pcre  *regex_SIZE;        /* For recognizing SIZE settings */
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 extern const pcre  *regex_EARLY_PIPE;  /* For recognizing PIPE_CONNCT */
 #endif
 extern const pcre  *regex_ismsgid;     /* Compiled r.e. for message it */
diff --git a/src/src/macro_predef.c b/src/src/macro_predef.c
index ebb4cb98a..fce981996 100644
--- a/src/src/macro_predef.c
+++ b/src/src/macro_predef.c
@@ -158,6 +158,9 @@ due to conflicts with other common macros. */
 #ifndef DISABLE_OCSP
   builtin_macro_create(US"_HAVE_OCSP");
 #endif
+#ifdef SUPPORT_PIPE_CONNECT
+  builtin_macro_create(US"_HAVE_PIPE_CONNECT");
+#endif
 #ifndef DISABLE_PRDR
   builtin_macro_create(US"_HAVE_PRDR");
 #endif
@@ -197,9 +200,6 @@ due to conflicts with other common macros. */
 #ifdef EXPERIMENTAL_DSN_INFO
   builtin_macro_create(US"_HAVE_DSN_INFO");
 #endif
-#ifdef EXPERIMENTAL_PIPE_CONNECT
-  builtin_macro_create(US"_HAVE_PIPE_CONNECT");
-#endif
 #ifdef EXPERIMENTAL_TLS_RESUME
   builtin_macro_create(US"_HAVE_TLS_RESUME");
 #endif
diff --git a/src/src/readconf.c b/src/src/readconf.c
index cffee4a08..b9d193554 100644
--- a/src/src/readconf.c
+++ b/src/src/readconf.c
@@ -241,7 +241,7 @@ static optionlist optionlist_config[] = {
 #endif
   { "pid_file_path",            opt_stringptr,   &pid_file_path },
   { "pipelining_advertise_hosts", opt_stringptr, &pipelining_advertise_hosts },
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   { "pipelining_connect_advertise_hosts", opt_stringptr,
 						 &pipe_connect_advertise_hosts },
 #endif
@@ -4207,7 +4207,7 @@ Returns:     nothing
 static void
 auths_init(void)
 {
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 int nauths = 0;
 #endif
 
@@ -4233,11 +4233,11 @@ for (auth_instance * au = auths; au; au = au->next)
           "(%s and %s) have the same public name (%s)",
           au->client ? US"client" : US"server", au->name, bu->name,
           au->public_name);
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   nauths++;
 #endif
   }
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 f.smtp_in_early_pipe_no_auth = nauths > 16;
 #endif
 }
diff --git a/src/src/receive.c b/src/src/receive.c
index 9769e8893..ed2afb317 100644
--- a/src/src/receive.c
+++ b/src/src/receive.c
@@ -1343,7 +1343,7 @@ if (received_protocol)
 if (LOGGING(pipelining) && f.smtp_in_pipelining_advertised)
   {
   g = string_catn(g, US" L", 2);
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   if (f.smtp_in_early_pipe_used)
     g = string_catn(g, US"*", 1);
   else if (f.smtp_in_early_pipe_advertised)
diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c
index 049f5b542..1e478a6ac 100644
--- a/src/src/smtp_in.c
+++ b/src/src/smtp_in.c
@@ -142,7 +142,7 @@ static struct {
   BOOL helo_verify			:1;
   BOOL helo_seen			:1;
   BOOL helo_accept_junk			:1;
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   BOOL pipe_connect_acceptable		:1;
 #endif
   BOOL rcpt_smtp_response_same		:1;
@@ -397,7 +397,7 @@ return TRUE;
 }
 
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 static BOOL
 pipeline_connect_sends(void)
 {
@@ -2995,7 +2995,7 @@ while (*p);
 /* Before we write the banner, check that there is no input pending, unless
 this synchronisation check is disabled. */
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 fl.pipe_connect_acceptable =
   sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK;
 
@@ -3022,7 +3022,7 @@ if (!check_sync())
 /*XXX the ehlo-resp code does its own tls/nontls bit.  Maybe subroutine that? */
 
 smtp_printf("%s",
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   fl.pipe_connect_acceptable && pipeline_connect_sends(),
 #else
   FALSE,
@@ -3973,7 +3973,7 @@ while (done <= 0)
 #endif
 
   switch(smtp_read_command(
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	  !fl.pipe_connect_acceptable,
 #else
 	  TRUE,
@@ -4213,7 +4213,7 @@ while (done <= 0)
 	  host_build_sender_fullhost();  /* Rebuild */
 	  break;
 	  }
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	else if (!fl.pipe_connect_acceptable && !check_sync())
 #else
 	else if (!check_sync())
@@ -4344,7 +4344,7 @@ while (done <= 0)
 	  sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
 	  f.smtp_in_pipelining_advertised = TRUE;
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	  if (fl.pipe_connect_acceptable)
 	    {
 	    f.smtp_in_early_pipe_advertised = TRUE;
@@ -4462,7 +4462,7 @@ while (done <= 0)
 #ifndef DISABLE_TLS
       if (tls_in.active.sock >= 0)
 	(void)tls_write(NULL, g->s, g->ptr,
-# ifdef EXPERIMENTAL_PIPE_CONNECT
+# ifdef SUPPORT_PIPE_CONNECT
 			fl.pipe_connect_acceptable && pipeline_connect_sends());
 # else
 			FALSE);
@@ -5240,7 +5240,7 @@ while (done <= 0)
       f.dot_ends = TRUE;
 
     DATA_BDAT:		/* Common code for DATA and BDAT */
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
       fl.pipe_connect_acceptable = FALSE;
 #endif
       if (!discarded && recipients_count <= 0)
diff --git a/src/src/smtp_out.c b/src/src/smtp_out.c
index ea052b58a..c1cf901dc 100644
--- a/src/src/smtp_out.c
+++ b/src/src/smtp_out.c
@@ -699,7 +699,7 @@ int count = 0;
 
 errno = 0;  /* Ensure errno starts out zero */
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 if (sx->pending_BANNER || sx->pending_EHLO)
   {
   int rc;
diff --git a/src/src/structs.h b/src/src/structs.h
index 9fade0091..0b01d5880 100644
--- a/src/src/structs.h
+++ b/src/src/structs.h
@@ -623,7 +623,7 @@ typedef struct address_item {
     BOOL af_tcp_fastopen:1;		/* delivery usefully used TCP Fast Open */
     BOOL af_tcp_fastopen_data:1;	/* delivery sent SMTP commands on TCP Fast Open */
     BOOL af_pipelining:1;		/* delivery used (traditional) pipelining */
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     BOOL af_early_pipe:1;		/* delivery used connect-time pipelining */
 #endif
 #ifndef DISABLE_PRDR
diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c
index f3ea6b28b..ea30ff7ca 100644
--- a/src/src/tls-openssl.c
+++ b/src/src/tls-openssl.c
@@ -3395,14 +3395,14 @@ a store reset there, so use POOL_PERM. */
 
 if ((more || corked))
   {
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   int save_pool = store_pool;
   store_pool = POOL_PERM;
 #endif
 
   corked = string_catn(corked, buff, len);
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   store_pool = save_pool;
 #endif
 
diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index 5c7b440c1..baf304405 100644
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -106,7 +106,7 @@ optionlist smtp_transport_options[] = {
 #endif
   { "hosts_override",       opt_bool,
       (void *)offsetof(smtp_transport_options_block, hosts_override) },
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   { "hosts_pipe_connect",   opt_stringptr,
       (void *)offsetof(smtp_transport_options_block, hosts_pipe_connect) },
 #endif
@@ -256,7 +256,7 @@ smtp_transport_options_block smtp_transport_option_defaults = {
   .hosts_avoid_tls =		NULL,
   .hosts_verify_avoid_tls =	NULL,
   .hosts_avoid_pipelining =	NULL,
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   .hosts_pipe_connect =		NULL,
 #endif
   .hosts_avoid_esmtp =		NULL,
@@ -815,7 +815,7 @@ return TRUE;
 
 
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 static uschar *
 ehlo_cache_key(const smtp_context * sx)
 {
@@ -1081,7 +1081,7 @@ address_item * addr = sx->sync_addr;
 smtp_transport_options_block * ob = sx->conn_args.ob;
 int yield = 0;
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 int rc;
 if ((rc = smtp_reap_early_pipe(sx, &count)) != OK)
   return rc == FAIL ? -4 : -5;
@@ -1397,7 +1397,7 @@ smtp_auth(smtp_context * sx)
 host_item * host = sx->conn_args.host;			/* host to deliver to */
 smtp_transport_options_block * ob = sx->conn_args.ob;	/* transport options */
 int require_auth = verify_check_given_host(CUSS &ob->hosts_require_auth, host);
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 unsigned short authbits = tls_out.active.sock >= 0
       ? sx->ehlo_resp.crypted_auths : sx->ehlo_resp.cleartext_auths;
 #endif
@@ -1413,7 +1413,7 @@ if (!regex_AUTH)
 
 if (  sx->esmtp
    &&
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
       sx->early_pipe_active ? authbits
       :
 #endif
@@ -1423,7 +1423,7 @@ if (  sx->esmtp
   uschar * names = NULL;
   expand_nmax = -1;                          /* reset */
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   if (!sx->early_pipe_active)
 #endif
     names = string_copyn(expand_nstring[1], expand_nlength[1]);
@@ -1437,7 +1437,7 @@ if (  sx->esmtp
     DEBUG(D_transport) debug_printf("scanning authentication mechanisms\n");
     fail_reason = US"no common mechanisms were found";
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     if (sx->early_pipe_active)
       {
       /* Scan our authenticators (which support use by a client and were offered
@@ -1794,7 +1794,7 @@ if (  checks & OPTION_SIZE
    && pcre_exec(regex_SIZE, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
   checks &= ~OPTION_SIZE;
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 if (  checks & OPTION_EARLY_PIPE
    && pcre_exec(regex_EARLY_PIPE, NULL, CS buf, bsize, 0,
 		PCRE_EOPT, NULL, 0) < 0)
@@ -1841,7 +1841,7 @@ there may be more writes (like, the chunk data) done soon. */
 
 if (chunk_size > 0)
   {
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   BOOL new_conn = !!(sx->outblock.conn_args);
 #endif
   if((cmd_count = smtp_write_command(sx,
@@ -1850,7 +1850,7 @@ if (chunk_size > 0)
      ) < 0) return ERROR;
   if (flags & tc_chunk_last)
     data_command = string_copy(big_buffer);  /* Save for later error message */
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   /* That command write could have been the one that made the connection.
   Copy the fd from the client conn ctx (smtp transport specific) to the
   generic transport ctx. */
@@ -1883,7 +1883,7 @@ if (flags & tc_reap_prev  &&  prev_cmd_count > 0)
 
     case -5: errno = ERRNO_TLSFAILURE;
 	     return DEFER;
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     case -4:				/* non-2xx for pipelined banner or EHLO */
 #endif
     case -1:				/* Timeout on RCPT */
@@ -1977,7 +1977,7 @@ sx->conn_args.dane = FALSE;
 sx->dane_required =
   verify_check_given_host(CUSS &ob->hosts_require_dane, sx->conn_args.host) == OK;
 #endif
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 sx->early_pipe_active = sx->early_pipe_ok = FALSE;
 sx->ehlo_resp.cleartext_features = sx->ehlo_resp.crypted_features = 0;
 sx->pending_BANNER = sx->pending_EHLO = FALSE;
@@ -2105,7 +2105,7 @@ if (!continue_hostname)
   sx->inblock.cctx = sx->outblock.cctx = &sx->cctx;
   sx->avoid_option = sx->peer_offered = smtp_peer_options = 0;
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   if (  verify_check_given_host(CUSS &ob->hosts_pipe_connect,
 					    sx->conn_args.host) == OK)
 
@@ -2180,7 +2180,7 @@ will be?  Somehow I doubt it. */
 
   if (!sx->smtps)
     {
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     if (sx->early_pipe_active)
       {
       sx->pending_BANNER = TRUE;	/* sync_responses() must eventually handle */
@@ -2281,7 +2281,7 @@ goto SEND_QUIT;
   if (sx->esmtp)
     {
     if (smtp_write_command(sx,
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	  sx->early_pipe_active ? SCMD_BUFFER :
 #endif
 	    SCMD_FLUSH,
@@ -2289,7 +2289,7 @@ goto SEND_QUIT;
       goto SEND_FAILED;
     sx->esmtp_sent = TRUE;
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     if (sx->early_pipe_active)
       {
       sx->pending_EHLO = TRUE;
@@ -2322,7 +2322,7 @@ goto SEND_QUIT;
     DEBUG(D_transport)
       debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   if (!sx->early_pipe_active)
 #endif
     if (!sx->esmtp)
@@ -2357,13 +2357,13 @@ goto SEND_QUIT;
 
   if (sx->esmtp || sx->lmtp)
     {
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     if (!sx->early_pipe_active)
 #endif
       {
       sx->peer_offered = ehlo_response(sx->buffer,
 	OPTION_TLS	/* others checked later */
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	| (sx->early_pipe_ok
 	  ?   OPTION_IGNQ
 	    | OPTION_CHUNKING | OPTION_PRDR | OPTION_DSN | OPTION_PIPE | OPTION_SIZE
@@ -2375,7 +2375,7 @@ goto SEND_QUIT;
 	  )
 #endif
 	);
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
       if (sx->early_pipe_ok)
 	{
 	sx->ehlo_resp.cleartext_features = sx->peer_offered;
@@ -2468,7 +2468,7 @@ if (  smtp_peer_options & OPTION_TLS
   if (smtp_write_command(sx, SCMD_FLUSH, "STARTTLS\r\n") < 0)
     goto SEND_FAILED;
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   /* If doing early-pipelining reap the banner and EHLO-response but leave
   the response for the STARTTLS we just sent alone. */
 
@@ -2572,7 +2572,7 @@ if (tls_out.active.sock >= 0)
     goto SEND_QUIT;
     }
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   /* For SMTPS there is no cleartext early-pipe; use the crypted permission bit.
   We're unlikely to get the group sent and delivered before the server sends its
   banner, but it's still worth sending as a group.
@@ -2590,7 +2590,7 @@ if (tls_out.active.sock >= 0)
 
   /* For SMTPS we need to wait for the initial OK response. */
   if (sx->smtps)
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     if (sx->early_pipe_active)
       {
       sx->pending_BANNER = TRUE;
@@ -2613,14 +2613,14 @@ if (tls_out.active.sock >= 0)
     }
 
   if (smtp_write_command(sx,
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	sx->early_pipe_active ? SCMD_BUFFER :
 #endif
 	  SCMD_FLUSH,
 	"%s %s\r\n", greeting_cmd, sx->helo_data) < 0)
     goto SEND_FAILED;
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   if (sx->early_pipe_active)
     sx->pending_EHLO = TRUE;
   else
@@ -2685,13 +2685,13 @@ if (continue_hostname == NULL
   {
   if (sx->esmtp || sx->lmtp)
     {
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   if (!sx->early_pipe_active)
 #endif
     {
     sx->peer_offered = ehlo_response(sx->buffer,
 	0 /* no TLS */
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
 	| (sx->lmtp && ob->lmtp_ignore_quota ? OPTION_IGNQ : 0)
 	| OPTION_DSN | OPTION_PIPE | OPTION_SIZE
 	| OPTION_CHUNKING | OPTION_PRDR | OPTION_UTF8
@@ -2712,7 +2712,7 @@ if (continue_hostname == NULL
 	| (ob->size_addition >= 0 ? OPTION_SIZE : 0)
 #endif
       );
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     if (tls_out.active.sock >= 0)
       sx->ehlo_resp.crypted_features = sx->peer_offered;
 #endif
@@ -2760,7 +2760,7 @@ if (continue_hostname == NULL
     DEBUG(D_transport) debug_printf("%susing DSN\n",
 			sx->peer_offered & OPTION_DSN ? "" : "not ");
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     if (  sx->early_pipe_ok
        && !sx->early_pipe_active
        && tls_out.active.sock >= 0
@@ -3276,7 +3276,7 @@ for (addr = sx->first_addr, address_count = 0;
       case -2: return -2;			/* non-MAIL read i/o error */
       default: return -1;			/* any MAIL error */
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
       case -4: return -1;			/* non-2xx for pipelined banner or EHLO */
       case -5: return -1;			/* TLS first-read error */
 #endif
@@ -3608,7 +3608,7 @@ if (  !(sx.peer_offered & OPTION_CHUNKING)
 
     case -1: goto END_OFF;		/* Timeout on RCPT */
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
     case -5:				/* TLS first-read error */
     case -4:  HDEBUG(D_transport)
 		debug_printf("failed reaping pipelined cmd responses\n");
@@ -3754,7 +3754,7 @@ else
 
       case -1: goto END_OFF;		/* Timeout on RCPT */
 
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
       case -5:				/* TLS first-read error */
       case -4:  HDEBUG(D_transport)
 		  debug_printf("failed reaping pipelined cmd responses\n");
@@ -3906,7 +3906,7 @@ else
 	if (tcp_out_fastopen >= TFO_USED_DATA) setflag(addr, af_tcp_fastopen_data);
 	}
       if (sx.pipelining_used) setflag(addr, af_pipelining);
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
       if (sx.early_pipe_active) setflag(addr, af_early_pipe);
 #endif
 #ifndef DISABLE_PRDR
@@ -4108,7 +4108,7 @@ if (!sx.ok)
 
     else
       {
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
       /* If we were early-pipelinng and the actual EHLO response did not match
       the cached value we assumed, we could have detected it and passed a
       custom errno through to here.  It would be nice to RSET and retry right
diff --git a/src/src/transports/smtp.h b/src/src/transports/smtp.h
index 5200fcb74..79d674fa1 100644
--- a/src/src/transports/smtp.h
+++ b/src/src/transports/smtp.h
@@ -46,7 +46,7 @@ typedef struct {
   uschar *hosts_avoid_tls;
   uschar *hosts_verify_avoid_tls;
   uschar *hosts_avoid_pipelining;
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   uschar *hosts_pipe_connect;
 #endif
   uschar *hosts_avoid_esmtp;
@@ -121,7 +121,7 @@ typedef struct {
   BOOL smtps:1;
   BOOL ok:1;
   BOOL setting_up:1;
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   BOOL early_pipe_ok:1;
   BOOL early_pipe_active:1;
 #endif
@@ -138,7 +138,7 @@ typedef struct {
 #if !defined(DISABLE_TLS) && defined(SUPPORT_DANE)
   BOOL dane_required:1;
 #endif
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   BOOL pending_BANNER:1;
   BOOL pending_EHLO:1;
 #endif
@@ -160,7 +160,7 @@ typedef struct {
   uschar *	smtp_greeting;
   uschar *	helo_response;
 #endif
-#ifdef EXPERIMENTAL_PIPE_CONNECT
+#ifdef SUPPORT_PIPE_CONNECT
   ehlo_resp_precis	ehlo_resp;
 #endif