3942 inject sanity into ipadm tcp buffer size properties
3943 _snd_lowat_fraction tcp tunable has no effect
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Peng Dai <peng.dai@delphix.com>

*** 20,29 ****
--- 20,30 ----
   */
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2011, Joyent Inc. All rights reserved.
   * Copyright (c) 2013, OmniTI Computer Consulting, Inc. All rights reserved.
+  * Copyright (c) 2013 by Delphix. All rights reserved.
   */
  
  #ifndef _INET_TCP_IMPL_H
  #define _INET_TCP_IMPL_H
  
*** 52,61 ****
--- 53,73 ----
  extern struct qinit     tcp_winit;
  
  extern sock_downcalls_t sock_tcp_downcalls;
  
  /*
+  * Note that by default, the _snd_lowat_fraction tunable controls the value of
+  * the transmit low water mark.  TCP_XMIT_LOWATER (and thus the _xmit_lowat
+  * property) is only used if the administrator has disabled _snd_lowat_fraction
+  * by setting it to 0.
+  */
+ #define TCP_XMIT_LOWATER        4096
+ #define TCP_XMIT_HIWATER        49152
+ #define TCP_RECV_LOWATER        2048
+ #define TCP_RECV_HIWATER        128000
+ 
+ /*
   * Bind hash list size and has function.  It has to be a power of 2 for
   * hashing.
   */
  #define TCP_BIND_FANOUT_SIZE    1024
  #define TCP_BIND_HASH(lport) (ntohs(lport) & (TCP_BIND_FANOUT_SIZE - 1))