.\"
.\" Copyright (c) 2025-2026  Mateusz Piotrowski <0mp@FreeBSD.org>
.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.Dd May 7, 2026
.Dt DTRACE_MIB 4
.Os
.Sh NAME
.Nm dtrace_mib
.Nd a DTrace provider for Management Information Base
.Sh SYNOPSIS
.Cm mib: Ns Ar module Ns Cm \&:count: Ns Ar counter
.Pp
In
.Xr config 5 :
.Cd "options KDTRACE_MIB_SDT"
.Sh DESCRIPTION
The
.Nm mib
provider allows tracing of Management Information Base stats counters.
.Pp
The list of instrumented
.Ar module Ns s
includes:
.Bl -tag -offset indent -width ipcomp -compact
.It Cm ah
IP Authentication Header (RFC 2402),
.Xr ipsec 4
.It Cm esp
IP Encapsulating Security Payload (RFC 1827, RFC 2406),
.Xr ipsec 4
.It Cm icmp
.Xr icmp 4
.It Cm icmp6
.Xr icmp6 4
.It Cm ip
.Xr ip 4
.It Cm ip6
.Xr ip6 4
.It Cm ipcomp
IP Payload Compression Protocol,
.Xr ipsec 4
.It Cm ipsec
.Xr ipsec 4
.It Cm tcp
.Xr tcp 4
.It Cm udp
.Xr udp 4
.El
.Pp
The
.Cm mib: Ns Ar module Ns Cm \&:count: Ns Ar counter
probes fire when the
.Ar counter
in
.Ar module Ns s
increases.
.Pp
The first probe argument,
.Vt uint64_t Va args[0] ,
is the increment that the
.Ar counter
will increase by.
.Pp
Note that some probes like
.Cm mib:esp:count:esps_hist
or
.Cm mib:icmp6:count:icp6s_outhist
provide additional probe-specific arguments.
.Sh EXAMPLES
.Ss Example 1 : Tracing IP Stats Counters
When debugging network issues one common clue is an unexpectedly
incrementing error counter.
This is helpful, in that it gives us an
idea of what might be going wrong, but often these counters may be
incremented in different functions.
.Pp
Trace all
.Nm mib
probes in the
.Xr ip 4
module and print the current count and a stack trace:
.Pp
.Bd -literal -offset 2n
# dtrace -n 'mib:ip:count: { printf("%d", arg0); stack(); }'
dtrace: description 'mib:ip:count: ' matched 29 probes
CPU     ID                    FUNCTION:NAME
  7  98784               count:ips_localout 1
              kernel`ip_output+0x17a2
              kernel`udp_send+0xaca
              kernel`sosend_dgram+0x315
              kernel`sousrsend+0x79
              kernel`kern_sendit+0x1be
              kernel`sendit+0x1ab
              kernel`sys_sendmsg+0x5b
              kernel`amd64_syscall+0x169
              kernel`0xffffffff81094b8b
.Ed
.Sh SEE ALSO
.Xr dtrace 1 ,
.Xr dtrace_ip 4 ,
.Xr dtrace_tcp 4 ,
.Xr dtrace_udp 4 ,
.Xr tracing 7 ,
.Xr sysctl 8
.Sh STANDARDS
The probe descriptions in
the
.Fx
.Nm mib
provider are not compatible with those in the Solaris/illumos mib provider.
.Sh AUTHORS
.An -nosplit
The
.Nm mib
provider was added to
.Fx
by
.An Kristof Provost Aq Mt kp@FreeBSD.org .
.Pp
This manual page was written by
.An Mateusz Piotrowski Aq Mt 0mp@FreeBSD.org .