xref: /freebsd/usr.sbin/ifmcstat/ifmcstat.8 (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
1.\"	$KAME: ifmcstat.8,v 1.6 2002/10/31 04:23:43 suz Exp $
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3.\" Copyright (c) 2007-2009 Bruce Simpson.
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31.\" $FreeBSD$
32.\"
33.Dd May 27, 2009
34.Dt IFMCSTAT 8
35.Os
36.Sh NAME
37.Nm ifmcstat
38.Nd dump multicast group management statistics per interface
39.Sh SYNOPSIS
40.Nm
41.Op Fl i Ar interface
42.Op Fl f Ar address-family
43.Op Fl v
44.Op Fl K
45.Op Fl M Ar core
46.Op Fl N Ar system
47.\"
48.Sh DESCRIPTION
49The
50.Nm
51command dumps multicast group information from the kernel.
52.Pp
53The following options are supported:
54.Bl -tag -width Fl
55.It Fl i Ar interface
56specifies the interface to be displayed.
57.Pp
58.It Fl f Ar address-family
59specifies the address family to be displayed;
60.Ar inet ,
61.Ar inet6
62and
63.Ar link
64are supported.
65.It Fl v
66specifies that link-layer memberships should be printed;
67they are suppressed by default.
68It may not be specified for
69.Fl f Ar link .
70Source lists for each group will also be printed.
71.Pp
72If specified twice, and
73.Xr kvm 3
74is in use, the control plane timers for each interface
75and the source list counters for each group
76will also be printed.
77.El
78.Pp
79The following options are only available if
80.Nm
81has been built with support for
82.Xr kvm 3 :
83.Bl -tag -width Fl
84.It Fl K
85attempts to use
86.Xr kvm 3
87to retrieve the multicast group information.
88.It Fl M Ar core
89extracts values associated with the name list from the specified core,
90instead of the default
91.Pa /dev/kmem .
92.It Fl N Ar system
93extracts the name list from the specified kernel instead of the
94default, which is the kernel image the system has booted from.
95.El
96.Sh IMPLEMENTATION NOTES
97.Nm
98will always print the embedded scope IDs of IPv6 multicast group
99memberships.
100This is because memberships are always scoped to an interface.
101.Pp
102When run with the
103.Fl v
104option,
105.Nm
106may print multicast MAC addresses twice if they are
107referenced by a layer 3 protocol.
108.Pp
109When run with
110.Xr kvm 3
111support,
112the names of all interfaces configured in the system will be
113printed in the first column of output, even if no multicast
114group memberships are present on those interfaces.
115The output may also be slightly different, as the kernel
116data structures are being traversed with minimal post-processing
117of the output.
118.Pp
119When built without
120.Xr kvm 3
121support, the information displayed by
122.Nm
123is more limited.
124This support is recommended for debugging purposes.
125It requires super-user privilege if used to inspect a running kernel.
126.Pp
127.Sh SEE ALSO
128.Xr netstat 1 ,
129.Xr getifaddrs 3 ,
130.Xr getifmaddrs 3 ,
131.Xr kvm 3
132