MacOS: TCP Fast Open

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

diff --git a/src/src/smtp_out.c b/src/src/smtp_out.c
index db33ac66e26990c7ba0be6222ff0dd58106ee604..c5eafbc57499f003bdd66742925c73bea293db62 100644 (file)
--- a/src/src/smtp_out.c
+++ b/src/src/smtp_out.c
@@ -2,7 +2,7 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 

-/* Copyright (c) University of Cambridge 1995 - 2016 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */

 /* See the file NOTICE for conditions of use and distribution. */
 
 /* A number of functions for driving outgoing SMTP calls. */
 /* See the file NOTICE for conditions of use and distribution. */
 
 /* A number of functions for driving outgoing SMTP calls. */


@@ -45,7 +45,7 @@ if (!istring) return TRUE;
 
 if (!(expint = expand_string(istring)))
   {
 
 if (!(expint = expand_string(istring)))
   {

-  if (expand_string_forcedfail) return TRUE;
+  if (f.expand_string_forcedfail) return TRUE;

   addr->transport_return = PANIC;
   addr->message = string_sprintf("failed to expand \"interface\" "
       "option for %s: %s", msg, expand_string_message);
   addr->transport_return = PANIC;
   addr->message = string_sprintf("failed to expand \"interface\" "
       "option for %s: %s", msg, expand_string_message);


@@ -140,8 +140,62 @@ return TRUE;
 
 
 
 
 
 

+#ifdef TCP_FASTOPEN
+static void
+tfo_out_check(int sock)
+{
+# if defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
+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;
+
+#  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. */
+
+      /* If there was data-on-SYN but we had to retrasnmit it, declare no TFO */
+
+    case TFO_USED:
+      if (!(tinfo.tcpi_options & TCPI_OPT_SYN_DATA))
+       {
+       DEBUG(D_transport|D_v) debug_printf("TFO: had to retransmit\n");
+       tcp_out_fastopen = TFO_NOT_USED;
+       }
+      break;
+
+  default: break;      /* compiler quietening */
+#  endif
+    }
+# endif
+}
+#endif
+
+

 /* Arguments as for smtp_connect(), plus
 /* Arguments as for smtp_connect(), plus

-  early_data   if non-NULL, data to be sent - preferably in the TCP SYN segment
+  early_data   if non-NULL, idenmpotent data to be sent -
+               preferably in the TCP SYN segment

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


@@ -158,6 +212,8 @@ int dscp_level;
 int dscp_option;
 int sock;
 int save_errno = 0;
 int dscp_option;
 int sock;
 int save_errno = 0;

+const blob * fastopen_blob = NULL;
+

 
 #ifndef DISABLE_EVENT
 deliver_host_address = host->address;
 
 #ifndef DISABLE_EVENT
 deliver_host_address = host->address;


@@ -207,16 +263,14 @@ requested some early-data then include that in the TFO request. */
 
 else
   {
 
 else
   {

-  const blob * fastopen = NULL;
-

 #ifdef TCP_FASTOPEN
 #ifdef TCP_FASTOPEN

-  if (verify_check_given_host(&ob->hosts_try_fastopen, host) == OK)
-    fastopen = early_data ? early_data : &tcp_fastopen_nodata;
+  if (verify_check_given_host(CUSS &ob->hosts_try_fastopen, host) == OK)
+    fastopen_blob = early_data ? early_data : &tcp_fastopen_nodata;

 #endif
 
 #endif
 

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

     save_errno = errno;
     save_errno = errno;

-  else if (early_data && !fastopen && early_data->data && early_data->len)
+  else if (early_data && !fastopen_blob && early_data->data && early_data->len)

     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;
   }


@@ -254,6 +308,9 @@ else
     return -1;
     }
   if (ob->keepalive) ip_keepalive(sock, host->address, TRUE);
     return -1;
     }
   if (ob->keepalive) ip_keepalive(sock, host->address, TRUE);

+#ifdef TCP_FASTOPEN
+  if (fastopen_blob) tfo_out_check(sock);
+#endif

   return sock;
   }
 }
   return sock;
   }
 }


@@ -354,11 +411,11 @@ HDEBUG(D_transport|D_acl) debug_printf_indent("cmd buf flush %d bytes%s\n", n,
   more ? " (more expected)" : "");
 
 #ifdef SUPPORT_TLS
   more ? " (more expected)" : "");
 
 #ifdef SUPPORT_TLS

-if (tls_out.active == outblock->sock)
-  rc = tls_write(FALSE, outblock->buffer, n, more);
+if (outblock->cctx->tls_ctx)
+  rc = tls_write(outblock->cctx->tls_ctx, outblock->buffer, n, more);

 else
 #endif
 else
 #endif

-  rc = send(outblock->sock, outblock->buffer, n,
+  rc = send(outblock->cctx->sock, outblock->buffer, n,

 #ifdef MSG_MORE
            more ? MSG_MORE : 0
 #else
 #ifdef MSG_MORE
            more ? MSG_MORE : 0
 #else


@@ -387,7 +444,7 @@ return TRUE;
 any error message.
 
 Arguments:
 any error message.
 
 Arguments:

-  outblock   contains buffer for pipelining, and socket
+  sx        SMTP connection, contains buffer for pipelining, and socket

   mode       buffer, write-with-more-likely, write
   format     a format, starting with one of
              of HELO, MAIL FROM, RCPT TO, DATA, ".", or QUIT.
   mode       buffer, write-with-more-likely, write
   format     a format, starting with one of
              of HELO, MAIL FROM, RCPT TO, DATA, ".", or QUIT.


@@ -400,8 +457,9 @@ Returns:     0 if command added to pipelining buffer, with nothing transmitted
 */
 
 int
 */
 
 int

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

 {
 {

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

 int count;
 int rc = 0;
 va_list ap;
 int count;
 int rc = 0;
 va_list ap;


@@ -489,7 +547,7 @@ read_response_line(smtp_inblock *inblock, uschar *buffer, int size, int timeout)
 uschar *p = buffer;
 uschar *ptr = inblock->ptr;
 uschar *ptrend = inblock->ptrend;
 uschar *p = buffer;
 uschar *ptr = inblock->ptr;
 uschar *ptrend = inblock->ptrend;

-int sock = inblock->sock;
+client_conn_ctx * cctx = inblock->cctx;

 
 /* Loop for reading multiple packets or reading another packet after emptying
 a previously-read one. */
 
 /* Loop for reading multiple packets or reading another packet after emptying
 a previously-read one. */


@@ -527,7 +585,7 @@ for (;;)
 
   /* Need to read a new input packet. */
 
 
   /* Need to read a new input packet. */
 

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

     {
     DEBUG(D_deliver|D_transport|D_acl)
       debug_printf_indent(errno ? "  SMTP(%s)<<\n" : "  SMTP(closed)<<\n",
     {
     DEBUG(D_deliver|D_transport|D_acl)
       debug_printf_indent(errno ? "  SMTP(%s)<<\n" : "  SMTP(closed)<<\n",


@@ -566,7 +624,8 @@ also returned after a reading error. In this case buffer[0] will be zero, and
 the error code will be in errno.
 
 Arguments:
 the error code will be in errno.
 
 Arguments:

-  inblock   the SMTP input block (contains holding buffer, socket, etc.)
+  sx        the SMTP connection (contains input block with holding buffer,
+               socket, etc.)

   buffer    where to put the response
   size      the size of the buffer
   okdigit   the expected first digit of the response
   buffer    where to put the response
   size      the size of the buffer
   okdigit   the expected first digit of the response


@@ -576,9 +635,10 @@ Returns:    TRUE if a valid, non-error response was received; else FALSE
 */
 
 BOOL
 */
 
 BOOL

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

    int timeout)
 {
    int timeout)
 {

+smtp_inblock * inblock = &((smtp_context *)sx)->inblock;

 uschar *ptr = buffer;
 int count;
 
 uschar *ptr = buffer;
 int count;