svn commit: r367920 - head/tools/tools/netmap

[Vincenzo Maffione]

Author: vmaffione
Date: Sat Nov 21 18:20:21 2020
New Revision: 367920
URL: https://svnweb.freebsd.org/changeset/base/367920

Log:
  netmap: bridge: update man page with more information
  
  Update the man page to describe how it is necessary to
  enable promiscuous mode and/or disable offloads.

Modified:
  head/tools/tools/netmap/bridge.8

Modified: head/tools/tools/netmap/bridge.8
==============================================================================
--- head/tools/tools/netmap/bridge.8	Sat Nov 21 10:58:19 2020	(r367919)
+++ head/tools/tools/netmap/bridge.8	Sat Nov 21 18:20:21 2020	(r367920)
@@ -23,7 +23,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 28, 2018
+.Dd November 21, 2020
 .Dt BRIDGE 8
 .Os
 .Sh NAME
@@ -49,6 +49,20 @@ forwards packets without copying the packets payload (
 explicitly prevented by the
 .Fl c
 flag.
+.Pp
+When bridging two physical ports, it is necessary that both NICS are in
+promiscuous mode, otherwise unicast traffic directed to other hosts will
+be dropped by the hardware, and bridging will not work.
+.Pp
+When bridging the hardware rings of a physical port with the corresponding
+host rings, it is necessary to turn off the offloads, because netmap does
+not prepare the NIC rings with offload information.
+Example:
+.Bd -literal -offset intent
+ifconfig em0 -rxcsum -txcsum -tso4 -tso6 -lro
+.Ed
+.Pp
+Available options:
 .Bl -tag -width Ds
 .It Fl i Ar port
 Name of the netmap port.
@@ -71,8 +85,8 @@ Disable zero-copy mode.
 .El
 .Sh SEE ALSO
 .Xr netmap 4 ,
-.Xr pkt-gen 8 ,
-.Xr lb 8
+.Xr lb 8 ,
+.Xr pkt-gen 8
 .Sh AUTHORS
 .An -nosplit
 .Nm