TFO: better observability (slightly) on FreeBSD

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

diff --git a/src/src/smtp_out.c b/src/src/smtp_out.c
index ece79de10a52e22b9ee692cdaaef96eb897b923b..bb7a0e3b30e120b240a2caf98f3fc64bdcd86207 100644 (file)
--- a/src/src/smtp_out.c
+++ b/src/src/smtp_out.c
@@ -3,6 +3,7 @@
 *************************************************/
 
 /* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
 /* See the file NOTICE for conditions of use and distribution. */
 
 /* A number of functions for driving outgoing SMTP calls. */
@@ -63,9 +64,10 @@ if (is_tainted(expint))
   return FALSE;
   }
 
-while (isspace(*expint)) expint++;
-if (*expint == 0) return TRUE;
+Uskip_whitespace(&expint);
+if (!*expint) return TRUE;
 
+/* we just tested to ensure no taint, so big_buffer is ok */
 while ((iface = string_nextinlist(&expint, &sep, big_buffer,
           big_buffer_size)))
   {
@@ -155,7 +157,40 @@ return TRUE;
 static void
 tfo_out_check(int sock)
 {
-# if defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
+# ifdef __FreeBSD__
+struct tcp_info tinfo;
+socklen_t len = sizeof(tinfo);
+
+/* 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
+  */
+  }
+
+switch (tcp_out_fastopen)
+  {
+  case TFO_ATTEMPTED_DATA:     tcp_out_fastopen = TFO_USED_DATA; break;
+  default: break; /* compiler quietening */
+  }
+
+# else /* Linux & Apple */
+#  if defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
 struct tcp_info tinfo;
 socklen_t len = sizeof(tinfo);
 
@@ -205,7 +240,8 @@ switch (tcp_out_fastopen)
 
   default: break; /* compiler quietening */
   }
-# endif
+#  endif
+# endif        /* Linux & Apple */
 }
 #endif
 
@@ -352,7 +388,7 @@ smtp_port_for_connect(host_item * host, int port)
 {
 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;
@@ -478,7 +514,7 @@ else
     rc = n;
     }
   else
-
+    {
     rc = send(outblock->cctx->sock, outblock->buffer, n,
 #ifdef MSG_MORE
              more ? MSG_MORE : 0
@@ -486,6 +522,17 @@ else
              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(outblock->cctx->sock, IPPROTO_TCP, TCP_CORK, &off, sizeof(off));
+#endif
+    }
   }
 
 if (rc <= 0)
@@ -575,7 +622,7 @@ if (format)
       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);
@@ -717,7 +764,7 @@ time_t timelimit = time(NULL) + timeout;
 
 errno = 0;  /* Ensure errno starts out zero */
 
-#ifdef SUPPORT_PIPE_CONNECT
+#ifndef DISABLE_PIPE_CONNECT
 if (sx->pending_BANNER || sx->pending_EHLO)
   {
   int rc;