xref: /freebsd/usr.sbin/ifmcstat/ifmcstat.8 (revision 640235e2c2ba32947f7c59d168437ffa1280f1e6)
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.It Fl f Ar address-family
58specifies the address family to be displayed;
59.Ar inet ,
60.Ar inet6
61and
62.Ar link
63are supported.
64.It Fl v
65specifies that link-layer memberships should be printed;
66they are suppressed by default.
67It may not be specified for
68.Fl f Ar link .
69Source lists for each group will also be printed.
70.Pp
71If specified twice, and
72.Xr kvm 3
73is in use, the control plane timers for each interface
74and the source list counters for each group
75will also be printed.
76.El
77.Pp
78The following options are only available if
79.Nm
80has been built with support for
81.Xr kvm 3 :
82.Bl -tag -width Fl
83.It Fl K
84attempts to use
85.Xr kvm 3
86to retrieve the multicast group information.
87.It Fl M Ar core
88extracts values associated with the name list from the specified core,
89instead of the default
90.Pa /dev/kmem .
91.It Fl N Ar system
92extracts the name list from the specified kernel instead of the
93default, which is the kernel image the system has booted from.
94.El
95.Sh IMPLEMENTATION NOTES
96.Nm
97will always print the embedded scope IDs of IPv6 multicast group
98memberships.
99This is because memberships are always scoped to an interface.
100.Pp
101When run with the
102.Fl v
103option,
104.Nm
105may print multicast MAC addresses twice if they are
106referenced by a layer 3 protocol.
107.Pp
108When run with
109.Xr kvm 3
110support,
111the names of all interfaces configured in the system will be
112printed in the first column of output, even if no multicast
113group memberships are present on those interfaces.
114The output may also be slightly different, as the kernel
115data structures are being traversed with minimal post-processing
116of the output.
117.Pp
118When built without
119.Xr kvm 3
120support, the information displayed by
121.Nm
122is more limited.
123This support is recommended for debugging purposes.
124It requires super-user privilege if used to inspect a running kernel.
125.Sh SEE ALSO
126.Xr netstat 1 ,
127.Xr getifaddrs 3 ,
128.Xr getifmaddrs 3 ,
129.Xr kvm 3
130