SPDX: Mass-update to GPL-2.0-or-later

[exim.git] / src / src / smtp_out.c

diff --git a/src/src/smtp_out.c b/src/src/smtp_out.c
index ef2c9fdeb37a0d07e0beb7b8026b1d7ff48c00e2..e705965bac21252dcc327f4fd7b6330045bd7386 100644 (file)
--- a/src/src/smtp_out.c
+++ b/src/src/smtp_out.c
@@ -2,8 +2,10 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 

+/* Copyright (c) The Exim Maintainers 2020 - 2022 */

 /* Copyright (c) University of Cambridge 1995 - 2018 */
 /* See the file NOTICE for conditions of use and distribution. */
 /* Copyright (c) University of Cambridge 1995 - 2018 */
 /* See the file NOTICE for conditions of use and distribution. */

+/* SPDX-License-Identifier: GPL-2.0-or-later */

 
 /* A number of functions for driving outgoing SMTP calls. */
 
 
 /* A number of functions for driving outgoing SMTP calls. */
 


@@ -26,7 +28,7 @@ Arguments:
                which case the function does nothing
   host_af    AF_INET or AF_INET6 for the outgoing IP address
   addr       the mail address being handled (for setting errors)
                which case the function does nothing
   host_af    AF_INET or AF_INET6 for the outgoing IP address
   addr       the mail address being handled (for setting errors)

-  interface  point this to the interface
+  interface  point this to the interface if there is one defined

   msg        to add to any error message
 
 Returns:     TRUE on success, FALSE on failure, with error message
   msg        to add to any error message
 
 Returns:     TRUE on success, FALSE on failure, with error message


@@ -52,13 +54,24 @@ if (!(expint = expand_string(istring)))
   return FALSE;
   }
 
   return FALSE;
   }
 

-while (isspace(*expint)) expint++;
-if (*expint == 0) return TRUE;
+if (is_tainted(expint))
+  {
+  log_write(0, LOG_MAIN|LOG_PANIC,
+    "attempt to use tainted value '%s' from '%s' for interface",
+    expint, istring);
+  addr->transport_return = PANIC;
+  addr->message = string_sprintf("failed to expand \"interface\" "
+      "option for %s: configuration error", msg);
+  return FALSE;
+  }
+
+Uskip_whitespace(&expint);
+if (!*expint) return TRUE;

 
 

-while ((iface = string_nextinlist(&expint, &sep, big_buffer,
-          big_buffer_size)))
+while ((iface = string_nextinlist(&expint, &sep, NULL, 0)))

   {
   {

-  if (string_is_ip_address(iface, NULL) == 0)
+  int if_af = string_is_ip_address(iface, NULL);
+  if (if_af == 0)

     {
     addr->transport_return = PANIC;
     addr->message = string_sprintf("\"%s\" is not a valid IP "
     {
     addr->transport_return = PANIC;
     addr->message = string_sprintf("\"%s\" is not a valid IP "


@@ -67,11 +80,11 @@ while ((iface = string_nextinlist(&expint, &sep, big_buffer,
     return FALSE;
     }
 
     return FALSE;
     }
 

-  if (((Ustrchr(iface, ':') == NULL)? AF_INET:AF_INET6) == host_af)
+  if ((if_af == 4 ? AF_INET : AF_INET6) == host_af)

     break;
   }
 
     break;
   }
 

-if (iface) *interface = string_copy(iface);
+*interface = iface;

 return TRUE;
 }
 
 return TRUE;
 }
 


@@ -141,86 +154,120 @@ return TRUE;
 
 
 #ifdef TCP_FASTOPEN
 
 
 #ifdef TCP_FASTOPEN

+/* Try to record if TFO was attmepted and if it was successfully used.  */
+

 static void
 tfo_out_check(int sock)
 {
 static void
 tfo_out_check(int sock)
 {

-# if defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
+static BOOL done_once = FALSE;
+
+if (done_once) return;
+done_once = TRUE;
+
+# ifdef __FreeBSD__

 struct tcp_info tinfo;
 socklen_t len = sizeof(tinfo);
 
 struct tcp_info tinfo;
 socklen_t len = sizeof(tinfo);
 

-if (getsockopt(sock, IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
-  switch (tcp_out_fastopen)
-    {
-      /* This is a somewhat dubious detection method; totally undocumented so likely
-      to fail in future kernels.  There seems to be no documented way.  What we really
-      want to know is if the server sent smtp-banner data before our ACK of his SYN,ACK
-      hit him.  What this (possibly?) detects is whether we sent a TFO cookie with our
-      SYN, as distinct from a TFO request.  This gets a false-positive when the server
-      key is rotated; we send the old one (which this test sees) but the server returns
-      the new one and does not send its SMTP banner before we ACK his SYN,ACK.
-       To force that rotation case:
-       '# echo -n "00000000-00000000-00000000-0000000" >/proc/sys/net/ipv4/tcp_fastopen_key'
-      The kernel seems to be counting unack'd packets. */
-
-    case TFO_ATTEMPTED:
-      if (tinfo.tcpi_unacked > 1)
-       {
-       DEBUG(D_transport|D_v)
-         debug_printf("TCP_FASTOPEN tcpi_unacked %d\n", tinfo.tcpi_unacked);
-       tcp_out_fastopen = TFO_USED;
-       }
-      break;
+/* A getsockopt TCP_FASTOPEN unfortunately returns "was-used" for a TFO/R as
+well as a TFO/C.  Use what we can of the Linux hack below; reliability issues ditto. */
+switch (tcp_out_fastopen)
+  {
+  case TFO_ATTEMPTED_NODATA:
+    if (  getsockopt(sock, IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
+       && tinfo.tcpi_state == TCPS_SYN_SENT
+       && tinfo.__tcpi_unacked > 0
+       )
+      {
+      DEBUG(D_transport|D_v)
+       debug_printf("TCP_FASTOPEN tcpi_unacked %d\n", tinfo.__tcpi_unacked);
+      tcp_out_fastopen = TFO_USED_NODATA;
+      }
+    break;
+  /*
+  case TFO_ATTEMPTED_DATA:
+  case TFO_ATTEMPTED_DATA:
+       if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)   XXX no equvalent as of 12.2
+  */
+  }

 
 

-#  ifdef notdef                /* This seems to always fire, meaning that we cannot tell
-                       whether the server accepted data we sent.  For now assume
-                       that it did. */
+switch (tcp_out_fastopen)
+  {
+  case TFO_ATTEMPTED_DATA:     tcp_out_fastopen = TFO_USED_DATA; break;
+  default: break; /* compiler quietening */
+  }

 
 

-      /* If there was data-on-SYN but we had to retrasnmit it, declare no TFO */
+# else /* Linux & Apple */
+#  if defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
+struct tcp_info tinfo;
+socklen_t len = sizeof(tinfo);

 
 

-    case TFO_USED:
-      if (!(tinfo.tcpi_options & TCPI_OPT_SYN_DATA))
+switch (tcp_out_fastopen)
+  {
+    /* This is a somewhat dubious detection method; totally undocumented so likely
+    to fail in future kernels.  There seems to be no documented way.  What we really
+    want to know is if the server sent smtp-banner data before our ACK of his SYN,ACK
+    hit him.  What this (possibly?) detects is whether we sent a TFO cookie with our
+    SYN, as distinct from a TFO request.  This gets a false-positive when the server
+    key is rotated; we send the old one (which this test sees) but the server returns
+    the new one and does not send its SMTP banner before we ACK his SYN,ACK.
+     To force that rotation case:
+     '# echo -n "00000000-00000000-00000000-0000000" >/proc/sys/net/ipv4/tcp_fastopen_key'
+    The kernel seems to be counting unack'd packets. */
+
+  case TFO_ATTEMPTED_NODATA:
+    if (  getsockopt(sock, IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
+       && tinfo.tcpi_state == TCP_SYN_SENT
+       && tinfo.tcpi_unacked > 1
+       )
+      {
+      DEBUG(D_transport|D_v)
+       debug_printf("TCP_FASTOPEN tcpi_unacked %d\n", tinfo.tcpi_unacked);
+      tcp_out_fastopen = TFO_USED_NODATA;
+      }
+    break;
+
+    /* When called after waiting for received data we should be able
+    to tell if data we sent was accepted. */
+
+  case TFO_ATTEMPTED_DATA:
+    if (  getsockopt(sock, IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
+       && tinfo.tcpi_state == TCP_ESTABLISHED
+       )
+      if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
+       {
+       DEBUG(D_transport|D_v) debug_printf("TFO: data was acked\n");
+       tcp_out_fastopen = TFO_USED_DATA;
+       }
+      else

        {
        DEBUG(D_transport|D_v) debug_printf("TFO: had to retransmit\n");
        tcp_out_fastopen = TFO_NOT_USED;
        }
        {
        DEBUG(D_transport|D_v) debug_printf("TFO: had to retransmit\n");
        tcp_out_fastopen = TFO_NOT_USED;
        }

-      break;
+    break;

 
 

-  default: break;      /* compiler quietening */
+  default: break; /* compiler quietening */
+  }

 #  endif
 #  endif

-    }
-# endif
+# endif        /* Linux & Apple */

 }
 #endif
 
 
 }
 #endif
 
 

-/* Arguments as for smtp_connect(), plus
-  early_data   if non-NULL, data to be sent - preferably in the TCP SYN segment
-
-Returns:      connected socket number, or -1 with errno set
+/* Create and bind a socket, given the connect-args.
+Update those with the state.  Return the fd, or -1 with errno set.

 */
 
 int
 */
 
 int

-smtp_sock_connect(host_item * host, int host_af, int port, uschar * interface,
-  transport_instance * tb, int timeout, const blob * early_data)
+smtp_boundsock(smtp_connect_args * sc)

 {
 {

+transport_instance * tb = sc->tblock;

 smtp_transport_options_block * ob =
   (smtp_transport_options_block *)tb->options_block;
 const uschar * dscp = ob->dscp;
 smtp_transport_options_block * ob =
   (smtp_transport_options_block *)tb->options_block;
 const uschar * dscp = ob->dscp;

-int dscp_value;
-int dscp_level;
-int dscp_option;
-int sock;
-int save_errno = 0;
-const blob * fastopen_blob = NULL;
-
-
-#ifndef DISABLE_EVENT
-deliver_host_address = host->address;
-deliver_host_port = port;
-if (event_raise(tb->event_action, US"tcp:connect", NULL)) return -1;
-#endif
+int sock, dscp_value, dscp_level, dscp_option;

 
 

-if ((sock = ip_socket(SOCK_STREAM, host_af)) < 0) return -1;
+if ((sock = ip_socket(SOCK_STREAM, sc->host_af)) < 0)
+  return -1;

 
 /* Set TCP_NODELAY; Exim does its own buffering. */
 
 
 /* Set TCP_NODELAY; Exim does its own buffering. */
 


@@ -231,7 +278,7 @@ if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
 /* Set DSCP value, if we can. For now, if we fail to set the value, we don't
 bomb out, just log it and continue in default traffic class. */
 
 /* Set DSCP value, if we can. For now, if we fail to set the value, we don't
 bomb out, just log it and continue in default traffic class. */
 

-if (dscp && dscp_lookup(dscp, host_af, &dscp_level, &dscp_option, &dscp_value))
+if (dscp && dscp_lookup(dscp, sc->host_af, &dscp_level, &dscp_option, &dscp_value))

   {
   HDEBUG(D_transport|D_acl|D_v)
     debug_printf_indent("DSCP \"%s\"=%x ", dscp, dscp_value);
   {
   HDEBUG(D_transport|D_acl|D_v)
     debug_printf_indent("DSCP \"%s\"=%x ", dscp, dscp_value);


@@ -240,7 +287,7 @@ if (dscp && dscp_lookup(dscp, host_af, &dscp_level, &dscp_option, &dscp_value))
       debug_printf_indent("failed to set DSCP: %s ", strerror(errno));
   /* If the kernel supports IPv4 and IPv6 on an IPv6 socket, we need to set the
   option for both; ignore failures here */
       debug_printf_indent("failed to set DSCP: %s ", strerror(errno));
   /* If the kernel supports IPv4 and IPv6 on an IPv6 socket, we need to set the
   option for both; ignore failures here */

-  if (host_af == AF_INET6 &&
+  if (sc->host_af == AF_INET6 &&

       dscp_lookup(dscp, AF_INET, &dscp_level, &dscp_option, &dscp_value))
     (void) setsockopt(sock, dscp_level, dscp_option, &dscp_value, sizeof(dscp_value));
   }
       dscp_lookup(dscp, AF_INET, &dscp_level, &dscp_option, &dscp_value))
     (void) setsockopt(sock, dscp_level, dscp_option, &dscp_value, sizeof(dscp_value));
   }


@@ -248,55 +295,123 @@ if (dscp && dscp_lookup(dscp, host_af, &dscp_level, &dscp_option, &dscp_value))
 /* Bind to a specific interface if requested. Caller must ensure the interface
 is the same type (IPv4 or IPv6) as the outgoing address. */
 
 /* Bind to a specific interface if requested. Caller must ensure the interface
 is the same type (IPv4 or IPv6) as the outgoing address. */
 

-if (interface && ip_bind(sock, host_af, interface, 0) < 0)
+if (sc->interface)

   {
   {

-  save_errno = errno;
-  HDEBUG(D_transport|D_acl|D_v)
-    debug_printf_indent("unable to bind outgoing SMTP call to %s: %s", interface,
-    strerror(errno));
+  union sockaddr_46 interface_sock;
+  EXIM_SOCKLEN_T size = sizeof(interface_sock);
+
+  if (  ip_bind(sock, sc->host_af, sc->interface, 0) < 0
+     || getsockname(sock, (struct sockaddr *) &interface_sock, &size) < 0
+     )
+    {
+    HDEBUG(D_transport|D_acl|D_v)
+      debug_printf_indent("unable to bind outgoing SMTP call to %s: %s", sc->interface,
+       strerror(errno));
+    close(sock);
+    return -1;
+    }
+  sending_ip_address = host_ntoa(-1, &interface_sock, NULL, &sending_port);

   }
 
   }
 

+sc->sock = sock;
+return sock;
+}
+
+
+/* Arguments:
+  host        host item containing name and address and port
+  host_af     AF_INET or AF_INET6
+  port       TCP port number
+  interface   outgoing interface address or NULL
+  tb          transport
+  timeout     timeout value or 0
+  early_data   if non-NULL, idempotent data to be sent -
+               preferably in the TCP SYN segment
+             Special case: non-NULL but with NULL blob.data - caller is
+             client-data-first (eg. TLS-on-connect) and a lazy-TCP-connect is
+             acceptable.
+
+Returns:      connected socket number, or -1 with errno set
+*/
+
+int
+smtp_sock_connect(smtp_connect_args * sc, int timeout, const blob * early_data)
+{
+smtp_transport_options_block * ob =
+  (smtp_transport_options_block *)sc->tblock->options_block;
+int sock;
+int save_errno = 0;
+const blob * fastopen_blob = NULL;
+
+
+#ifndef DISABLE_EVENT
+deliver_host_address = sc->host->address;
+deliver_host_port = sc->host->port;
+if (event_raise(sc->tblock->event_action, US"tcp:connect", NULL, &errno)) return -1;
+#endif
+
+if (  (sock = sc->sock) < 0
+   && (sock = smtp_boundsock(sc)) < 0)
+  save_errno = errno;
+sc->sock = -1;
+

 /* Connect to the remote host, and add keepalive to the socket before returning
 it, if requested.  If the build supports TFO, request it - and if the caller
 /* Connect to the remote host, and add keepalive to the socket before returning
 it, if requested.  If the build supports TFO, request it - and if the caller

-requested some early-data then include that in the TFO request. */
+requested some early-data then include that in the TFO request.  If there is
+early-data but no TFO support, send it after connecting. */

 
 

-else
+if (!save_errno)

   {
 #ifdef TCP_FASTOPEN
   {
 #ifdef TCP_FASTOPEN

-  if (verify_check_given_host(CUSS &ob->hosts_try_fastopen, host) == OK)
-    fastopen_blob = early_data ? early_data : &tcp_fastopen_nodata;
+  /* See if TCP Fast Open usable.  Default is a traditional 3WHS connect */
+  if (verify_check_given_host(CUSS &ob->hosts_try_fastopen, sc->host) == OK)
+    {
+    if (!early_data)
+      fastopen_blob = &tcp_fastopen_nodata;    /* TFO, with no data */
+    else if (early_data->data)
+      fastopen_blob = early_data;              /* TFO, with data */
+# ifdef TCP_FASTOPEN_CONNECT
+    else
+      {                                                /* expecting client data */
+      DEBUG(D_transport|D_acl|D_v) debug_printf(" set up lazy-connect\n");
+      setsockopt(sock, IPPROTO_TCP, TCP_FASTOPEN_CONNECT, US &on, sizeof(on));
+      /* fastopen_blob = NULL;          lazy TFO, triggered by data write */
+      }
+# endif
+    }

 #endif
 
 #endif
 

-  if (ip_connect(sock, host_af, host->address, port, timeout, fastopen_blob) < 0)
+  if (ip_connect(sock, sc->host_af, sc->host->address, sc->host->port, timeout, fastopen_blob) < 0)

     save_errno = errno;
   else if (early_data && !fastopen_blob && early_data->data && early_data->len)
     save_errno = errno;
   else if (early_data && !fastopen_blob && early_data->data && early_data->len)

+    {
+    /* We had some early-data to send, but couldn't do TFO */
+    HDEBUG(D_transport|D_acl|D_v)
+      debug_printf("sending %ld nonTFO early-data\n", (long)early_data->len);
+
+#ifdef TCP_QUICKACK_notdef
+    (void) setsockopt(sock, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif

     if (send(sock, early_data->data, early_data->len, 0) < 0)
       save_errno = errno;
     if (send(sock, early_data->data, early_data->len, 0) < 0)
       save_errno = errno;

-  }
-
-/* Either bind() or connect() failed */
-
-if (save_errno != 0)
-  {
-  HDEBUG(D_transport|D_acl|D_v)
-    {
-    debug_printf_indent("failed: %s", CUstrerror(save_errno));
-    if (save_errno == ETIMEDOUT)
-      debug_printf(" (timeout=%s)", readconf_printtime(timeout));
-    debug_printf("\n");

     }
     }

-  (void)close(sock);
-  errno = save_errno;
-  return -1;
+#ifdef TCP_QUICKACK_notdef
+  /* Under TFO (with openssl & pipe-conn; testcase 4069, as of
+  5.10.8-100.fc32.x86_64) this seems to be inop.
+  Perhaps overwritten when we (client) go -> ESTABLISHED on seeing the 3rd-ACK?
+  For that case, added at smtp_reap_banner(). */
+  (void) setsockopt(sock, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif

   }
 
   }
 

-/* Both bind() and connect() succeeded */
-
-else
+if (!save_errno)

   {
   union sockaddr_46 interface_sock;
   EXIM_SOCKLEN_T size = sizeof(interface_sock);
   {
   union sockaddr_46 interface_sock;
   EXIM_SOCKLEN_T size = sizeof(interface_sock);

-  HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("connected\n");
+
+  /* Both bind() and connect() succeeded, and any early-data */
+
+  HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" connected\n");

   if (getsockname(sock, (struct sockaddr *)(&interface_sock), &size) == 0)
     sending_ip_address = host_ntoa(-1, &interface_sock, NULL, &sending_port);
   else
   if (getsockname(sock, (struct sockaddr *)(&interface_sock), &size) == 0)
     sending_ip_address = host_ntoa(-1, &interface_sock, NULL, &sending_port);
   else


@@ -306,12 +421,26 @@ else
     close(sock);
     return -1;
     }
     close(sock);
     return -1;
     }

-  if (ob->keepalive) ip_keepalive(sock, host->address, TRUE);
+
+  if (ob->keepalive) ip_keepalive(sock, sc->host->address, TRUE);

 #ifdef TCP_FASTOPEN
 #ifdef TCP_FASTOPEN

-  if (fastopen_blob) tfo_out_check(sock);
+  tfo_out_check(sock);

 #endif
   return sock;
   }
 #endif
   return sock;
   }

+
+/* Either bind() or connect() failed */
+
+HDEBUG(D_transport|D_acl|D_v)
+  {
+  debug_printf_indent(" failed: %s", CUstrerror(save_errno));
+  if (save_errno == ETIMEDOUT)
+    debug_printf(" (timeout=%s)", readconf_printtime(timeout));
+  debug_printf("\n");
+  }
+(void)close(sock);
+errno = save_errno;
+return -1;

 }
 
 
 }
 
 


@@ -323,7 +452,7 @@ smtp_port_for_connect(host_item * host, int port)
 {
 if (host->port != PORT_NONE)
   {
 {
 if (host->port != PORT_NONE)
   {

-  HDEBUG(D_transport|D_acl|D_v)
+  HDEBUG(D_transport|D_acl|D_v) if (port != host->port)

     debug_printf_indent("Transport port=%d replaced by host-specific port=%d\n", port,
       host->port);
   port = host->port;
     debug_printf_indent("Transport port=%d replaced by host-specific port=%d\n", port,
       host->port);
   port = host->port;


@@ -342,45 +471,64 @@ non-IPv6 systems, to enable the code to be less messy. However, on such systems
 host->address will always be an IPv4 address.
 
 Arguments:
 host->address will always be an IPv4 address.
 
 Arguments:

-  host        host item containing name and address and port
-  host_af     AF_INET or AF_INET6
-  interface   outgoing interface address or NULL
-  timeout     timeout value or 0
-  tb          transport
+  sc         details for making connection: host, af, interface, transport
+  early_data  if non-NULL, data to be sent - preferably in the TCP SYN segment
+             Special case: non-NULL but with NULL blob.data - caller is
+             client-data-first (eg. TLS-on-connect) and a lazy-TCP-connect is
+             acceptable.

 
 Returns:      connected socket number, or -1 with errno set
 */
 
 int
 
 Returns:      connected socket number, or -1 with errno set
 */
 
 int

-smtp_connect(host_item *host, int host_af, uschar *interface,
-  int timeout, transport_instance * tb)
+smtp_connect(smtp_connect_args * sc, const blob * early_data)

 {
 {

-int port = host->port;
-#ifdef SUPPORT_SOCKS
-smtp_transport_options_block * ob =
-  (smtp_transport_options_block *)tb->options_block;
-#endif
+int port = sc->host->port;
+smtp_transport_options_block * ob = sc->ob;

 
 

-callout_address = string_sprintf("[%s]:%d", host->address, port);
+callout_address = string_sprintf("[%s]:%d", sc->host->address, port);

 
 HDEBUG(D_transport|D_acl|D_v)
   {
   uschar * s = US" ";
 
 HDEBUG(D_transport|D_acl|D_v)
   {
   uschar * s = US" ";

-  if (interface) s = string_sprintf(" from %s ", interface);
+  if (sc->interface) s = string_sprintf(" from %s ", sc->interface);

 #ifdef SUPPORT_SOCKS
   if (ob->socks_proxy) s = string_sprintf("%svia proxy ", s);
 #endif
 #ifdef SUPPORT_SOCKS
   if (ob->socks_proxy) s = string_sprintf("%svia proxy ", s);
 #endif

-  debug_printf_indent("Connecting to %s %s%s... ", host->name, callout_address, s);
+  debug_printf_indent("Connecting to %s %s%s... ", sc->host->name, callout_address, s);

   }
 
 /* Create and connect the socket */
 
 #ifdef SUPPORT_SOCKS
 if (ob->socks_proxy)
   }
 
 /* Create and connect the socket */
 
 #ifdef SUPPORT_SOCKS
 if (ob->socks_proxy)

-  return socks_sock_connect(host, host_af, port, interface, tb, timeout);
+  {
+  int sock = socks_sock_connect(sc->host, sc->host_af, port, sc->interface,
+                               sc->tblock, ob->connect_timeout);
+  
+  if (sock >= 0)
+    {
+    if (early_data && early_data->data && early_data->len)
+      if (send(sock, early_data->data, early_data->len, 0) < 0)
+       {
+       int save_errno = errno;
+       HDEBUG(D_transport|D_acl|D_v)
+         {
+         debug_printf_indent("failed: %s", CUstrerror(save_errno));
+         if (save_errno == ETIMEDOUT)
+           debug_printf(" (timeout=%s)", readconf_printtime(ob->connect_timeout));
+         debug_printf("\n");
+         }
+       (void)close(sock);
+       sock = -1;
+       errno = save_errno;
+       }
+    }
+  return sock;
+  }

 #endif
 
 #endif
 

-return smtp_sock_connect(host, host_af, port, interface, tb, timeout, NULL);
+return smtp_sock_connect(sc, ob->connect_timeout, early_data);

 }
 
 
 }
 
 


@@ -405,22 +553,61 @@ flush_buffer(smtp_outblock * outblock, int mode)
 int rc;
 int n = outblock->ptr - outblock->buffer;
 BOOL more = mode == SCMD_MORE;
 int rc;
 int n = outblock->ptr - outblock->buffer;
 BOOL more = mode == SCMD_MORE;

+client_conn_ctx * cctx;

 
 HDEBUG(D_transport|D_acl) debug_printf_indent("cmd buf flush %d bytes%s\n", n,
   more ? " (more expected)" : "");
 
 
 HDEBUG(D_transport|D_acl) debug_printf_indent("cmd buf flush %d bytes%s\n", n,
   more ? " (more expected)" : "");
 

-#ifdef SUPPORT_TLS
-if (outblock->cctx->tls_ctx)
-  rc = tls_write(outblock->cctx->tls_ctx, outblock->buffer, n, more);
+if (!(cctx = outblock->cctx))
+  {
+  log_write(0, LOG_MAIN|LOG_PANIC, "null conn-context pointer");
+  errno = 0;
+  return FALSE;
+  }
+
+#ifndef DISABLE_TLS
+if (cctx->tls_ctx)             /*XXX have seen a null cctx here, rvfy sending QUIT, hence check above */
+  rc = tls_write(cctx->tls_ctx, outblock->buffer, n, more);

 else
 #endif
 else
 #endif

-  rc = send(outblock->cctx->sock, outblock->buffer, n,
+
+  {
+  if (outblock->conn_args)
+    {
+    blob early_data = { .data = outblock->buffer, .len = n };
+
+    /* We ignore the more-flag if we're doing a connect with early-data, which
+    means we won't get BDAT+data. A pity, but wise due to the idempotency
+    requirement: TFO with data can, in rare cases, replay the data to the
+    receiver. */
+
+    if (  (cctx->sock = smtp_connect(outblock->conn_args, &early_data))
+       < 0)
+      return FALSE;
+    outblock->conn_args = NULL;
+    rc = n;
+    }
+  else
+    {
+    rc = send(cctx->sock, outblock->buffer, n,

 #ifdef MSG_MORE
 #ifdef MSG_MORE

-           more ? MSG_MORE : 0
+             more ? MSG_MORE : 0

 #else
 #else

-           0
+             0
+#endif
+            );
+
+#if defined(__linux__)
+    /* This is a workaround for a current linux kernel bug: as of
+    5.6.8-200.fc31.x86_64  small (<MSS) writes get delayed by about 200ms,
+    This is despite NODELAY being active.
+    https://bugzilla.redhat.com/show_bug.cgi?id=1803806 */
+
+    if (!more)
+      setsockopt(cctx->sock, IPPROTO_TCP, TCP_CORK, &off, sizeof(off));

 #endif
 #endif

-          );
+    }
+  }

 
 if (rc <= 0)
   {
 
 if (rc <= 0)
   {


@@ -435,6 +622,22 @@ return TRUE;
 
 
 
 
 
 

+/* This might be called both due to callout and then from delivery.
+Use memory that will not be released between those phases.
+*/
+static void
+smtp_debug_resp(const uschar * buf)
+{
+#ifndef DISABLE_CLIENT_CMD_LOG
+int old_pool = store_pool;
+store_pool = POOL_PERM;
+client_cmd_log = string_append_listele_n(client_cmd_log, ':', buf,
+  buf[3] == ' ' ? 3 : 4);
+store_pool = old_pool;
+#endif
+}
+
+

 /*************************************************
 *             Write SMTP command                 *
 *************************************************/
 /*************************************************
 *             Write SMTP command                 *
 *************************************************/


@@ -456,37 +659,43 @@ Returns:     0 if command added to pipelining buffer, with nothing transmitted
 */
 
 int
 */
 
 int

-smtp_write_command(void * sx, int mode, const char *format, ...)
+smtp_write_command(void * sx, int mode, const char * format, ...)

 {
 smtp_outblock * outblock = &((smtp_context *)sx)->outblock;
 {
 smtp_outblock * outblock = &((smtp_context *)sx)->outblock;

-int count;

 int rc = 0;
 int rc = 0;

-va_list ap;

 
 if (format)
   {
 
 if (format)
   {

+  gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
+  va_list ap;
+
+  /* Use taint-unchecked routines for writing into big_buffer, trusting that
+  we'll never expand the results.  Actually, the error-message use - leaving
+  the results in big_buffer for potential later use - is uncomfortably distant.
+  XXX Would be better to assume all smtp commands are short, use normal pool
+  alloc rather than big_buffer, and another global for the data-for-error. */
+

   va_start(ap, format);
   va_start(ap, format);

-  if (!string_vformat(big_buffer, big_buffer_size, CS format, ap))
+  if (!string_vformat(&gs, SVFMT_TAINT_NOCHK, CS format, ap))

     log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
       "SMTP");
   va_end(ap);
     log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
       "SMTP");
   va_end(ap);

-  count = Ustrlen(big_buffer);
+  string_from_gstring(&gs);

 
 

-  if (count > outblock->buffersize)
+  if (gs.ptr > outblock->buffersize)

     log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
       "SMTP");
 
     log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
       "SMTP");
 

-  if (count > outblock->buffersize - (outblock->ptr - outblock->buffer))
+  if (gs.ptr > outblock->buffersize - (outblock->ptr - outblock->buffer))

     {
     rc = outblock->cmd_count;                 /* flush resets */
     if (!flush_buffer(outblock, SCMD_FLUSH)) return -1;
     }
 
     {
     rc = outblock->cmd_count;                 /* flush resets */
     if (!flush_buffer(outblock, SCMD_FLUSH)) return -1;
     }
 

-  Ustrncpy(CS outblock->ptr, big_buffer, count);
-  outblock->ptr += count;
+  Ustrncpy(outblock->ptr, gs.s, gs.ptr);
+  outblock->ptr += gs.ptr;

   outblock->cmd_count++;
   outblock->cmd_count++;

-  count -= 2;
-  big_buffer[count] = 0;     /* remove \r\n for error message */
+  gs.ptr -= 2; string_from_gstring(&gs); /* remove \r\n for error message */

 
   /* We want to hide the actual data sent in AUTH transactions from reflections
   and logs. While authenticating, a flag is set in the outblock to enable this.
 
   /* We want to hide the actual data sent in AUTH transactions from reflections
   and logs. While authenticating, a flag is set in the outblock to enable this.


@@ -503,10 +712,10 @@ if (format)
       while (!isspace(*p)) p++;
       while (isspace(*p)) p++;
       }
       while (!isspace(*p)) p++;
       while (isspace(*p)) p++;
       }

-    while (*p != 0) *p++ = '*';
+    while (*p) *p++ = '*';

     }
 
     }
 

-  HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  SMTP>> %s\n", big_buffer);
+  smtp_debug_cmd(big_buffer, mode);

   }
 
 if (mode != SCMD_BUFFER)
   }
 
 if (mode != SCMD_BUFFER)


@@ -534,14 +743,14 @@ Arguments:
   inblock   the SMTP input block (contains holding buffer, socket, etc.)
   buffer    where to put the line
   size      space available for the line
   inblock   the SMTP input block (contains holding buffer, socket, etc.)
   buffer    where to put the line
   size      space available for the line

-  timeout   the timeout to use when reading a packet
+  timelimit deadline for reading the lime, seconds past epoch

 
 Returns:    length of a line that has been put in the buffer
 
 Returns:    length of a line that has been put in the buffer

-            -1 otherwise, with errno set
+            -1 otherwise, with errno set, and inblock->ptr adjusted

 */
 
 static int
 */
 
 static int

-read_response_line(smtp_inblock *inblock, uschar *buffer, int size, int timeout)
+read_response_line(smtp_inblock *inblock, uschar *buffer, int size, time_t timelimit)

 {
 uschar *p = buffer;
 uschar *ptr = inblock->ptr;
 {
 uschar *p = buffer;
 uschar *ptr = inblock->ptr;


@@ -578,15 +787,16 @@ for (;;)
       {
       *p = 0;                     /* Leave malformed line for error message */
       errno = ERRNO_SMTPFORMAT;
       {
       *p = 0;                     /* Leave malformed line for error message */
       errno = ERRNO_SMTPFORMAT;

+      inblock->ptr = ptr;

       return -1;
       }
     }
 
   /* Need to read a new input packet. */
 
       return -1;
       }
     }
 
   /* Need to read a new input packet. */
 

-  if((rc = ip_recv(cctx, inblock->buffer, inblock->buffersize, timeout)) <= 0)
+  if((rc = ip_recv(cctx, inblock->buffer, inblock->buffersize, timelimit)) <= 0)

     {
     {

-    DEBUG(D_deliver|D_transport|D_acl)
+    DEBUG(D_deliver|D_transport|D_acl|D_v)

       debug_printf_indent(errno ? "  SMTP(%s)<<\n" : "  SMTP(closed)<<\n",
        strerror(errno));
     break;
       debug_printf_indent(errno ? "  SMTP(%s)<<\n" : "  SMTP(closed)<<\n",
        strerror(errno));
     break;


@@ -603,6 +813,7 @@ for (;;)
 /* Get here if there has been some kind of recv() error; errno is set, but we
 ensure that the result buffer is empty before returning. */
 
 /* Get here if there has been some kind of recv() error; errno is set, but we
 ensure that the result buffer is empty before returning. */
 

+inblock->ptr = inblock->ptrend = inblock->buffer;

 *buffer = 0;
 return -1;
 }
 *buffer = 0;
 return -1;
 }


@@ -632,27 +843,44 @@ Arguments:
 
 Returns:    TRUE if a valid, non-error response was received; else FALSE
 */
 
 Returns:    TRUE if a valid, non-error response was received; else FALSE
 */

+/*XXX could move to smtp transport; no other users */

 
 BOOL
 
 BOOL

-smtp_read_response(void * sx, uschar *buffer, int size, int okdigit,
+smtp_read_response(void * sx0, uschar * buffer, int size, int okdigit,

    int timeout)
 {
    int timeout)
 {

-smtp_inblock * inblock = &((smtp_context *)sx)->inblock;
-uschar *ptr = buffer;
-int count;
+smtp_context * sx = sx0;
+uschar * ptr = buffer;
+int count = 0;
+time_t timelimit = time(NULL) + timeout;
+BOOL yield = FALSE;

 
 errno = 0;  /* Ensure errno starts out zero */
 
 errno = 0;  /* Ensure errno starts out zero */

+buffer[0] = '\0';
+
+#ifndef DISABLE_PIPE_CONNECT
+if (sx->pending_BANNER || sx->pending_EHLO)
+  {
+  int rc;
+  if ((rc = smtp_reap_early_pipe(sx, &count)) != OK)
+    {
+    DEBUG(D_transport) debug_printf("failed reaping pipelined cmd responsess\n");
+    if (rc == DEFER) errno = ERRNO_TLSFAILURE;
+    goto out;
+    }
+  }
+#endif

 
 /* This is a loop to read and concatenate the lines that make up a multi-line
 response. */
 
 for (;;)
   {
 
 /* This is a loop to read and concatenate the lines that make up a multi-line
 response. */
 
 for (;;)
   {

-  if ((count = read_response_line(inblock, ptr, size, timeout)) < 0)
+  if ((count = read_response_line(&sx->inblock, ptr, size, timelimit)) < 0)

     return FALSE;
 
   HDEBUG(D_transport|D_acl|D_v)
     return FALSE;
 
   HDEBUG(D_transport|D_acl|D_v)

-    debug_printf_indent("  %s %s\n", (ptr == buffer)? "SMTP<<" : "      ", ptr);
+    debug_printf_indent("  %s %s\n", ptr == buffer ? "SMTP<<" : "      ", ptr);

 
   /* Check the format of the response: it must start with three digits; if
   these are followed by a space or end of line, the response is complete. If
 
   /* Check the format of the response: it must start with three digits; if
   these are followed by a space or end of line, the response is complete. If


@@ -669,7 +897,7 @@ for (;;)
      (ptr[3] != '-' && ptr[3] != ' ' && ptr[3] != 0))
     {
     errno = ERRNO_SMTPFORMAT;    /* format error */
      (ptr[3] != '-' && ptr[3] != ' ' && ptr[3] != 0))
     {
     errno = ERRNO_SMTPFORMAT;    /* format error */

-    return FALSE;
+    goto out;

     }
 
   /* If the line we have just read is a terminal line, line, we are done.
     }
 
   /* If the line we have just read is a terminal line, line, we are done.


@@ -686,6 +914,10 @@ for (;;)
   size -= count + 1;
   }
 
   size -= count + 1;
   }
 

+#ifdef TCP_FASTOPEN
+tfo_out_check(sx->cctx.sock);
+#endif
+

 /* Return a value that depends on the SMTP return code. On some systems a
 non-zero value of errno has been seen at this point, so ensure it is zero,
 because the caller of this function looks at errno when FALSE is returned, to
 /* Return a value that depends on the SMTP return code. On some systems a
 non-zero value of errno has been seen at this point, so ensure it is zero,
 because the caller of this function looks at errno when FALSE is returned, to


@@ -693,7 +925,11 @@ distinguish between an unexpected return code and other errors such as
 timeouts, lost connections, etc. */
 
 errno = 0;
 timeouts, lost connections, etc. */
 
 errno = 0;

-return buffer[0] == okdigit;
+yield = buffer[0] == okdigit;
+
+out:
+  smtp_debug_resp(buffer);
+  return yield;

 }
 
 /* End of smtp_out.c */
 }
 
 /* End of smtp_out.c */