Move QUICKACK disable as early as possible in server handling

[user/henk/code/exim.git] / src / src / smtp_out.c

diff --git a/src/src/smtp_out.c b/src/src/smtp_out.c
index 0bf619795f4a4999141635eb98890c1e10c3356a..b1a25f70a702b1fbc9ee252c557763696cd82ec6 100644 (file)
--- a/src/src/smtp_out.c
+++ b/src/src/smtp_out.c
@@ -159,20 +159,32 @@ tfo_out_check(int sock)
 {
 # ifdef __FreeBSD__
 struct tcp_info tinfo;
-int val;
-socklen_t len = sizeof(val);
+socklen_t len = sizeof(tinfo);
 
-/* The observability as of 12.1 is not useful as a client, only telling us that
-a TFO option was used on SYN.  It could have been a TFO-R, or ignored by the
-server. */
+/* 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
+  */
+  }
 
-/*
-if (tcp_out_fastopen == TFO_ATTEMPTED_NODATA || tcp_out_fastopen == TFO_ATTEMPTED_DATA)
-  if (getsockopt(sock, IPPROTO_TCP, TCP_FASTOPEN, &val, &len) == 0 && val != 0) {}
-*/
 switch (tcp_out_fastopen)
   {
-  case TFO_ATTEMPTED_NODATA:   tcp_out_fastopen = TFO_USED_NODATA; break;
   case TFO_ATTEMPTED_DATA:     tcp_out_fastopen = TFO_USED_DATA; break;
   default: break; /* compiler quietening */
   }
@@ -234,9 +246,18 @@ switch (tcp_out_fastopen)
 #endif
 
 
-/* Arguments as for smtp_connect(), plus
-  early_data   if non-NULL, idenmpotent data to be sent -
+/* 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
 */
@@ -306,8 +327,22 @@ early-data but no TFO support, send it after connecting. */
 else
   {
 #ifdef TCP_FASTOPEN
+  /* See if TCP Fast Open usable.  Default is a traditional 3WHS connect */
   if (verify_check_given_host(CUSS &ob->hosts_try_fastopen, host) == OK)
-    fastopen_blob = early_data ? early_data : &tcp_fastopen_nodata;
+    {
+    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_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
 
   if (ip_connect(sock, host_af, host->address, port, timeout, fastopen_blob) < 0)
@@ -317,12 +352,12 @@ else
     HDEBUG(D_transport|D_acl|D_v)
       debug_printf("sending %ld nonTFO early-data\n", (long)early_data->len);
 
-#ifdef TCP_QUICKACK
-    (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;
     }
+#ifdef TCP_QUICKACK
+    (void) setsockopt(sock, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif
   }
 
 /* Either bind() or connect() failed */
@@ -397,6 +432,9 @@ host->address will always be an IPv4 address.
 Arguments:
   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
 */