Document the unicast configuration options.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

ptp4l.8

@@ -1,4 +1,4 @@
-.TH PTP4l 8 "March 2018" "linuxptp"
+.TH PTP4l 8 "April 2018" "linuxptp"
 .SH NAME
 ptp4l - PTP Boundary/Ordinary/Transparent Clock
 
@@ -117,16 +117,28 @@ Each setting is placed on a separate line, it contains the name of the
 option and the value separated by whitespace characters. Empty lines and lines
 starting with # are ignored.
 
+There are three different section types.
+
+.TP
+.B 1.
 The global section (indicated as
 .BR [global] )
 sets the program options, clock options and default port options. Other
 sections are port specific sections and they override the default port options.
-The name of the section is the name of the configured port (e.g.
+.TP
+.B 2.
+Port sections give the name of the configured port (e.g.
 .BR [eth0] ).
 Ports specified in the configuration file don't need to be
 specified by the
 .B \-i
 option. An empty port section can be used to replace the command line option.
+.TP
+.B 3.
+Tables for configuring unicast discovery begin with
+.B \%[unicast_master_table].
+
+See UNICAST DISCOVERY OPTIONS, below.
 
 .SH PORT OPTIONS
 
@@ -219,6 +231,11 @@ delay requests using unicast delay responses. This option has no
 effect if the delay_mechanism is set to P2P.
 The default is 0 (disabled).
 .TP
+.B inhibit_multicast_service
+Some unicast mode profiles insist that no multicast message are ever
+transmitted.  Setting this option inhibits multicast transmission.
+The default is 0 (mutlicast enabled).
+.TP
 .B net_sync_monitor
 Enables the NetSync Monitor (NSM) protocol. The NSM protocol allows a
 station to measure how well another node is synchronized. The monitor
@@ -229,6 +246,26 @@ time stamps in the message to estimate the node's offset.  This option
 requires that the 'hybrid_e2e' option be enabled as well.
 The default is 0 (disabled).
 .TP
+.B unicast_listen
+When enabled, this option allows the port to grant unicast message
+contracts.  Incoming requests for will be granted limited only by the
+amount of memory available.
+The default is 0 (disabled).
+.TP
+.B unicast_master_table
+When set to a positive integer, this option specifies the table id to
+be used for unicast discovery.  Each table lives in its own section
+and has a unique, positive numerical ID.  Entries in the table are a
+pair of transport type and protocol address.  Tables may not be shared
+between ports, but nothing prevents table entries from appearing in
+more than table.
+The default is 0 (unicast discovery disabled).
+.TP
+.B unicast_req_duration
+The service time in seconds to be requested during unicast discovery.
+Note that the remote node is free to grant a different duration.
+The default is 3600 seconds or one hour.
+.TP
 .B ptp_dst_mac
 The MAC address to which PTP messages should be sent.
 Relevant only with L2 transport. The default is 01:1B:19:00:00:00.
@@ -625,6 +662,31 @@ of local clock in use. The value is purely informational, having no
 effect on the outcome of the Best Master Clock algorithm, and is
 advertised when the clock becomes grand master.
 
+.SH UNICAST DISCOVERY OPTIONS
+
+.TP
+.B table_id
+Each table must begin with a unique, positive table ID.  The port that
+claims a given table does so by including the ID as the value of
+its 'unicast_master_table' option.
+.TP
+.B logQueryInterval
+This option configures the time to wait between unicast negotiation
+attempts.  It is specified as a power of two in seconds.
+The default is 0 (1 second).
+.TP
+.B peer_address
+This option specifies the unicast address of the peer for use with the
+peer to peer delay mechanism.  If specified, the port owning the table
+will negotiate unicast peer delay responses from the machine at the
+given remote address, otherwise the port will send multicast peer
+delay requests.
+.TP
+.B L2|UDPv4
+Each table entry specifies the transport type and network address of a
+potential remote master.  If multiple masters are specified, then
+unicast negotiation will be performed with each if them.
+
 .SH TIME SCALE USAGE
 
 .B ptp4l