FreeBSD: better support for TFO

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

diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c
index b88fde1b56cc0174a9132a0ffb755a273de6dd13..c2e234ab552a449939b327523822653a4ad7f91f 100644 (file)
--- a/src/src/smtp_in.c
+++ b/src/src/smtp_in.c
@@ -2405,20 +2405,35 @@ struct tcp_info tinfo;
 socklen_t len = sizeof(tinfo);
 
 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
-#ifdef TCPI_OPT_SYN_DATA       /* FreeBSD 11 does not seem to have this yet */
+#  ifdef TCPI_OPT_SYN_DATA     /* FreeBSD 11,12 do not seem to have this yet */
   if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
     {
-    DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
+    DEBUG(D_receive)
+      debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n");
     f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE;
     }
   else
-#endif
-    if (tinfo.tcpi_state == TCP_SYN_RECV)
+#  endif
+    if (tinfo.tcpi_state == TCP_SYN_RECV)      /* Not seen on FreeBSD 12.1 */
+    {
+    DEBUG(D_receive)
+      debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
+    f.tcp_in_fastopen = TRUE;
+    }
+#  ifdef __FreeBSD__
+  else if (tinfo.tcpi_options & TCPOPT_FAST_OPEN)
     {
-    DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
+    /* This only tells us that some combination of the TCP options was used. It
+    can be a TFO-R received (as of 12.1).  However, pretend it shows real usage
+    (that an acceptable TFO-C was received and acted on).  Ignore the possibility
+    of data-on-SYN for now. */
+    DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (TFO option used)\n");
     f.tcp_in_fastopen = TRUE;
     }
+#  endif
 # endif
+else DEBUG(D_receive)
+  debug_printf("TCP_INFO getsockopt: %s\n", strerror(errno));
 }
 #endif