e6c0055599
Using args[2]->tcps_state as-documented results in error:
operator -> cannot be applied to pointer to type "void"
This error is accurate as the synopsis for tcp:::state-change is:
tcp:::state-change(void *, csinfo_t *, void *, tcpsinfo_t *, void *,
tcplsinfo_t *);
args[2] refers to the third argument which is always NULL (as-
documented). The to-state for the TCP connection state transition is
actually in the fourth argument, args[3]->tcps_state.
397 lines
12 KiB
Groff
397 lines
12 KiB
Groff
.\" Copyright (c) 2015 Mark Johnston <markj@FreeBSD.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd February 10, 2018
|
|
.Dt DTRACE_TCP 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm dtrace_tcp
|
|
.Nd a DTrace provider for tracing events related to the
|
|
.Xr tcp 4
|
|
protocol
|
|
.Sh SYNOPSIS
|
|
.Fn tcp:::accept-established "pktinfo_t *" "csinfo_t *" "ipinfo_t *" \
|
|
"tcpsinfo_t *" "tcpinfo_t *"
|
|
.Fn tcp:::accept-refused "pktinfo_t *" "csinfo_t *" "ipinfo_t *" \
|
|
"tcpsinfo_t *" "tcpinfo_t *"
|
|
.Fn tcp:::connect-established "pktinfo_t *" "csinfo_t *" "ipinfo_t *" \
|
|
"tcpsinfo_t *" "tcpinfo_t *"
|
|
.Fn tcp:::connect-refused "pktinfo_t *" "csinfo_t *" "ipinfo_t *" \
|
|
"tcpsinfo_t *" "tcpinfo_t *"
|
|
.Fn tcp:::connect-request "pktinfo_t *" "csinfo_t *" "ipinfo_t *" \
|
|
"tcpsinfo_t *" "tcpinfo_t *"
|
|
.Fn tcp:::receive "pktinfo_t *" "csinfo_t *" "ipinfo_t *" "tcpsinfo_t *" \
|
|
"tcpinfo_t *"
|
|
.Fn tcp:::send "pktinfo_t *" "csinfo_t *" "ipinfo_t *" "tcpsinfo_t *" \
|
|
"tcpinfo_t *"
|
|
.Fn tcp:::state-change "void *" "csinfo_t *" "void *" "tcpsinfo_t *" "void *" \
|
|
"tcplsinfo_t *"
|
|
.Sh DESCRIPTION
|
|
The DTrace
|
|
.Nm tcp
|
|
provider allows users to trace events in the
|
|
.Xr tcp 4
|
|
protocol implementation.
|
|
This provider is similar to the
|
|
.Xr dtrace_ip 4
|
|
and
|
|
.Xr dtrace_udp 4
|
|
providers, but additionally contains probes corresponding to protocol events at
|
|
a level higher than packet reception and transmission.
|
|
All
|
|
.Nm tcp
|
|
probes except for
|
|
.Fn tcp:::state-change
|
|
have the same number and type of arguments.
|
|
The last three arguments are used to describe a TCP segment: the
|
|
.Vt ipinfo_t
|
|
argument exposes the version-agnostic fields of the IP header, while the
|
|
.Vt tcpinfo_t
|
|
argument exposes the TCP header, and the
|
|
.Vt tcpsinfo_t
|
|
argument describes details of the corresponding TCP connection state, if any.
|
|
Their fields are described in the ARGUMENTS section.
|
|
.Pp
|
|
The
|
|
.Fn tcp:::accept-established
|
|
probe fires when a remotely-initiated active TCP open succeeds.
|
|
At this point the new connection is in the ESTABLISHED state, and the probe
|
|
arguments expose the headers associated with the final ACK of the three-way
|
|
handshake.
|
|
The
|
|
.Fn tcp:::accept-refused
|
|
probe fires when a SYN arrives on a port without a listening socket.
|
|
The probe arguments expose the headers associated with the RST to be transmitted
|
|
to the remote host in response to the SYN segment.
|
|
.Pp
|
|
The
|
|
.Fn tcp:::connect-established ,
|
|
.Fn tcp:::connect-refused ,
|
|
and
|
|
.Fn tcp:::connect-request
|
|
probes are similar to the
|
|
.Ql accept
|
|
probes, except that they correspond to locally-initiated TCP connections.
|
|
The
|
|
.Fn tcp:::connect-established
|
|
probe fires when the SYN-ACK segment of a three-way handshake is received from
|
|
the remote host and a final ACK is prepared for transmission.
|
|
This occurs immediately after the local connection state transitions from
|
|
SYN-SENT to ESTABLISHED.
|
|
The probe arguments describe the headers associated with the received SYN-ACK
|
|
segment.
|
|
The
|
|
.Fn tcp:::connect-refused
|
|
probe fires when the local host receives a RST segment in response to a SYN
|
|
segment, indicating that the remote host refused to open a connection.
|
|
The probe arguments describe the IP and TCP headers associated with the received
|
|
RST segment.
|
|
The
|
|
.Fn tcp:::connect-request
|
|
probe fires as the kernel prepares to transmit the initial SYN segment of a
|
|
three-way handshake.
|
|
.Pp
|
|
The
|
|
.Fn tcp:::send
|
|
and
|
|
.Fn tcp:::receive
|
|
probes fire when the host sends or receives a TCP packet, respectively.
|
|
As with the
|
|
.Xr dtrace_udp 4
|
|
provider,
|
|
.Nm tcp
|
|
probes fire only for packets sent by or to the local host; forwarded packets are
|
|
handled in the IP layer and are only visible to the
|
|
.Xr dtrace_ip 4
|
|
provider.
|
|
.Pp
|
|
The
|
|
.Fn tcp:::state-change
|
|
probe fires upon local TCP connection state transitions.
|
|
Its first, third and fifth arguments are currently always
|
|
.Dv NULL .
|
|
Its last argument describes the from-state in the transition, and the to-state
|
|
can be obtained from
|
|
.Dv args[3]->tcps_state .
|
|
.Sh ARGUMENTS
|
|
The
|
|
.Vt pktinfo_t
|
|
argument is currently unimplemented and is included for compatibility with other
|
|
implementations of this provider.
|
|
Its fields are:
|
|
.Bl -tag -width "uinptr_t pkt_addr" -offset indent
|
|
.It Vt uinptr_t pkt_addr
|
|
Always set to 0.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Vt csinfo_t
|
|
argument is currently unimplemented and is included for compatibility with other
|
|
implementations of this provider.
|
|
Its fields are:
|
|
.Bl -tag -width "uintptr_t cs_addr" -offset indent
|
|
.It Vt uintptr_t cs_addr
|
|
Always set to 0.
|
|
.It Vt uint64_t cs_cid
|
|
A pointer to the
|
|
.Vt struct inpcb
|
|
for this packet, or
|
|
.Dv NULL .
|
|
.It Vt pid_t cs_pid
|
|
Always set to 0.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Vt ipinfo_t
|
|
type is a version-agnostic representation of fields from an IP header.
|
|
Its fields are described in the
|
|
.Xr dtrace_ip 4
|
|
manual page.
|
|
.Pp
|
|
The
|
|
.Vt tcpsinfo_t
|
|
type is used to provide a stable representation of TCP connection state.
|
|
Some
|
|
.Nm tcp
|
|
probes, such as
|
|
.Fn tcp:::accept-refused ,
|
|
fire in a context where there is no TCP connection; this argument is
|
|
.Dv NULL
|
|
in that case.
|
|
Its fields are:
|
|
.Bl -tag -width "uint16_t tcps_lport" -offset indent
|
|
.It Vt uintptr_t tcps_addr
|
|
The address of the corresponding TCP control block.
|
|
This is currently a pointer to a
|
|
.Vt struct tcpcb .
|
|
.It Vt int tcps_local
|
|
A boolean indicating whether the connection is local to the host.
|
|
Currently unimplemented and always set to -1.
|
|
.It Vt int tcps_active
|
|
A boolean indicating whether the connection was initiated by the local host.
|
|
Currently unimplemented and always set to -1.
|
|
.It Vt uint16_t tcps_lport
|
|
Local TCP port.
|
|
.It Vt uint16_t tcps_rport
|
|
Remote TCP port.
|
|
.It Vt string tcps_laddr
|
|
Local address.
|
|
.It Vt string tcps_raddr
|
|
Remote address.
|
|
.It Vt int32_t tcps_state
|
|
Current TCP state.
|
|
The valid TCP state values are given by the constants prefixed with
|
|
.Ql TCPS_
|
|
in
|
|
.Pa /usr/lib/dtrace/tcp.d .
|
|
.It Vt uint32_t tcps_iss
|
|
Initial send sequence number.
|
|
.It Vt uint32_t tcps_suna
|
|
Initial sequence number of sent but unacknowledged data.
|
|
.It Vt uint32_t tcps_snxt
|
|
Next sequence number for send.
|
|
.It Vt uint32_t tcps_rack
|
|
Sequence number of received and acknowledged data.
|
|
.It Vt uint32_t tcps_rnxt
|
|
Next expected sequence number for receive.
|
|
.It Vt u_long tcps_swnd
|
|
TCP send window size.
|
|
.It Vt int32_t tcps_snd_ws
|
|
Window scaling factor for the TCP send window.
|
|
.It Vt u_long tcps_rwnd
|
|
TCP receive window size.
|
|
.It Vt int32_t tcps_rcv_ws
|
|
Window scaling factor for the TCP receive window.
|
|
.It Vt u_long tcps_cwnd
|
|
TCP congestion window size.
|
|
.It Vt u_long tcps_cwnd_ssthresh
|
|
Congestion window threshold at which slow start ends and congestion avoidance
|
|
begins.
|
|
.It Vt uint32_t tcps_sack_fack
|
|
Last sequence number selectively acknowledged by the receiver.
|
|
.It Vt uint32_t tcps_sack_snxt
|
|
Next selectively acknowledge sequence number at which to begin retransmitting.
|
|
.It Vt uint32_t tcps_rto
|
|
Round-trip timeout, in milliseconds.
|
|
.It Vt uint32_t tcps_mss
|
|
Maximum segment size.
|
|
.It Vt int tcps_retransmit
|
|
A boolean indicating that the local sender is retransmitting data.
|
|
.It Vt int tcps_srtt
|
|
Smoothed round-trip time.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Vt tcpinfo_t
|
|
type exposes the fields in a TCP segment header in host order.
|
|
Its fields are:
|
|
.Bl -tag -width "struct tcphdr *tcp_hdr" -offset indent
|
|
.It Vt uint16_t tcp_sport
|
|
Source TCP port.
|
|
.It Vt uint16_t tcp_dport
|
|
Destination TCP port.
|
|
.It Vt uint32_t tcp_seq
|
|
Sequence number.
|
|
.It Vt uint32_t tcp_ack
|
|
Acknowledgement number.
|
|
.It Vt uint8_t tcp_offset
|
|
Data offset, in bytes.
|
|
.It Vt uint8_t tcp_flags
|
|
TCP flags.
|
|
.It Vt uint16_t tcp_window
|
|
TCP window size.
|
|
.It Vt uint16_t tcp_checksum
|
|
Checksum.
|
|
.It Vt uint16_t tcp_urgent
|
|
Urgent data pointer.
|
|
.It Vt struct tcphdr *tcp_hdr
|
|
A pointer to the raw TCP header.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Vt tcplsinfo_t
|
|
type is used by the
|
|
.Fn tcp:::state-change
|
|
probe to provide the from-state of a transition.
|
|
Its fields are:
|
|
.Bl -tag -width "int32_t tcps_state" -offset indent
|
|
.It Vt int32_t tcps_state
|
|
A TCP state.
|
|
The valid TCP state values are given by the constants prefixed with
|
|
.Ql TCPS_
|
|
in
|
|
.Pa /usr/lib/dtrace/tcp.d .
|
|
.El
|
|
.Sh FILES
|
|
.Bl -tag -width "/usr/lib/dtrace/tcp.d" -compact
|
|
.It Pa /usr/lib/dtrace/tcp.d
|
|
DTrace type and translator definitions for the
|
|
.Nm tcp
|
|
provider.
|
|
.El
|
|
.Sh EXAMPLES
|
|
The following script logs TCP segments in real time:
|
|
.Bd -literal -offset indent
|
|
#pragma D option quiet
|
|
#pragma D option switchrate=10hz
|
|
|
|
dtrace:::BEGIN
|
|
{
|
|
printf(" %3s %15s:%-5s %15s:%-5s %6s %s\\n", "CPU",
|
|
"LADDR", "LPORT", "RADDR", "RPORT", "BYTES", "FLAGS");
|
|
}
|
|
|
|
tcp:::send
|
|
{
|
|
this->length = args[2]->ip_plength - args[4]->tcp_offset;
|
|
printf(" %3d %16s:%-5d -> %16s:%-5d %6d (", cpu, args[2]->ip_saddr,
|
|
args[4]->tcp_sport, args[2]->ip_daddr, args[4]->tcp_dport,
|
|
this->length);
|
|
printf("%s", args[4]->tcp_flags & TH_FIN ? "FIN|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_SYN ? "SYN|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_RST ? "RST|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_PUSH ? "PUSH|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_ACK ? "ACK|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_URG ? "URG|" : "");
|
|
printf("%s", args[4]->tcp_flags == 0 ? "null " : "");
|
|
printf("\b)\\n");
|
|
}
|
|
|
|
tcp:::receive
|
|
{
|
|
this->length = args[2]->ip_plength - args[4]->tcp_offset;
|
|
printf(" %3d %16s:%-5d <- %16s:%-5d %6d (", cpu,
|
|
args[2]->ip_daddr, args[4]->tcp_dport, args[2]->ip_saddr,
|
|
args[4]->tcp_sport, this->length);
|
|
printf("%s", args[4]->tcp_flags & TH_FIN ? "FIN|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_SYN ? "SYN|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_RST ? "RST|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_PUSH ? "PUSH|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_ACK ? "ACK|" : "");
|
|
printf("%s", args[4]->tcp_flags & TH_URG ? "URG|" : "");
|
|
printf("%s", args[4]->tcp_flags == 0 ? "null " : "");
|
|
printf("\b)\\n");
|
|
}
|
|
.Ed
|
|
The following script logs TCP connection state changes as they occur:
|
|
.Bd -literal -offset indent
|
|
#pragma D option quiet
|
|
#pragma D option switchrate=25hz
|
|
|
|
int last[int];
|
|
|
|
dtrace:::BEGIN
|
|
{
|
|
printf(" %12s %-20s %-20s %s\\n",
|
|
"DELTA(us)", "OLD", "NEW", "TIMESTAMP");
|
|
}
|
|
|
|
tcp:::state-change
|
|
{
|
|
this->elapsed = (timestamp - last[args[1]->cs_cid]) / 1000;
|
|
printf(" %12d %-20s -> %-20s %d\\n", this->elapsed,
|
|
tcp_state_string[args[5]->tcps_state],
|
|
tcp_state_string[args[3]->tcps_state], timestamp);
|
|
last[args[1]->cs_cid] = timestamp;
|
|
}
|
|
|
|
tcp:::state-change
|
|
/last[args[1]->cs_cid] == 0/
|
|
{
|
|
printf(" %12s %-20s -> %-20s %d\\n", "-",
|
|
tcp_state_string[args[5]->tcps_state],
|
|
tcp_state_string[args[3]->tcps_state], timestamp);
|
|
last[args[1]->cs_cid] = timestamp;
|
|
}
|
|
.Ed
|
|
.Sh COMPATIBILITY
|
|
This provider is compatible with the
|
|
.Nm tcp
|
|
provider in Solaris.
|
|
.Sh SEE ALSO
|
|
.Xr dtrace 1 ,
|
|
.Xr dtrace_ip 4 ,
|
|
.Xr dtrace_udp 4 ,
|
|
.Xr tcp 4 ,
|
|
.Xr SDT 9
|
|
.Sh HISTORY
|
|
The
|
|
.Nm tcp
|
|
provider first appeared in
|
|
.Fx
|
|
10.0.
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Mark Johnston Aq Mt markj@FreeBSD.org .
|
|
.Sh BUGS
|
|
The
|
|
.Vt tcps_local
|
|
and
|
|
.Vt tcps_active
|
|
fields of
|
|
.Vt tcpsinfo_t
|
|
are not filled in by the translator.
|