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This is the "kttcp" network throughput testing pseudo-device. From 

the block comment at the top of the file:

      This module provides kernel support for testing network
      throughput from the perspective of the kernel.  It is
      similar in spirit to the classic ttcp network benchmark
      program, the main difference being that with kttcp, the
      kernel is the source and sink of the data.

      Testing like this is useful for a few reasons:

      1. This allows us to know what kind of performance we can
         expect from network applications that run in the kernel
         space, such as the NFS server or the NFS client.  These
         applications don't have to move the data to/from userspace,
         and so benchmark programs which run in userspace don't
         give us an accurate model.

      2. Since data received is just thrown away, the receiver
         is very fast.  This can provide better exercise for the
         sender at the other end.

      3. Since the NetBSD kernel currently uses a run-to-completion
         scheduling model, kttcp provides a benchmark model where
         preemption of the benchmark program is not an issue.

There is a companion "kttcp" user program which uses the kttcp
pseudo-device.

Largely written by Frank van der Linden, with some modifications
from me.
This commit is contained in:
thorpej 2002-06-28 23:27:13 +00:00
parent 32b1596627
commit 473e69750b
4 changed files with 699 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
sys/conf/files
View File

@ -1,4 +1,4 @@
# $NetBSD: files,v 1.538 2002/06/28 22:32:58 drochner Exp $
# $NetBSD: files,v 1.539 2002/06/28 23:27:13 thorpej Exp $
# @(#)files.newconf 7.5 (Berkeley) 5/10/93
@ -921,6 +921,10 @@ defpseudo isdn: isdndev, tty
defpseudo irip: isdndev, ifnet
defpseudo ippp: isdndev, sppp, ifnet
# KTTCP network throughput testing pseudo-device
defpseudo kttcp
file dev/kttcp.c kttcp needs-flag
#
# File systems
#

4
sys/dev/Makefile
View File

@ -1,4 +1,4 @@
# $NetBSD: Makefile,v 1.10 2001/12/04 21:43:44 augustss Exp $
# $NetBSD: Makefile,v 1.11 2002/06/28 23:27:14 thorpej Exp $
SUBDIR= ata dec hpc i2o ic ir isa ofw pci pckbc pcmcia raidframe \
sbus scsipi sun tc usb vme wscons
@ -7,6 +7,6 @@ KDIR= /sys/dev
INCSDIR= /usr/include/dev
# Only install includes which are used by userland
INCS= ccdvar.h md.h vndvar.h
INCS= ccdvar.h kttcpio.h md.h vndvar.h
.include <bsd.kinc.mk>

634
sys/dev/kttcp.c Normal file
View File

@ -0,0 +1,634 @@
/* $NetBSD: kttcp.c,v 1.1 2002/06/28 23:27:14 thorpej Exp $ */
/*
* Copyright (c) 2002 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Frank van der Linden and Jason R. Thorpe for
* Wasabi Systems, Inc.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
* 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.
*/
/*
* kttcp.c --
*
* This module provides kernel support for testing network
* throughput from the perspective of the kernel. It is
* similar in spirit to the classic ttcp network benchmark
* program, the main difference being that with kttcp, the
* kernel is the source and sink of the data.
*
* Testing like this is useful for a few reasons:
*
* 1. This allows us to know what kind of performance we can
* expect from network applications that run in the kernel
* space, such as the NFS server or the NFS client. These
* applications don't have to move the data to/from userspace,
* and so benchmark programs which run in userspace don't
* give us an accurate model.
*
* 2. Since data received is just thrown away, the receiver
* is very fast. This can provide better exercise for the
* sender at the other end.
*
* 3. Since the NetBSD kernel currently uses a run-to-completion
* scheduling model, kttcp provides a benchmark model where
* preemption of the benchmark program is not an issue.
*/
#include <sys/param.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/conf.h>
#include <sys/systm.h>
#include <sys/protosw.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/signal.h>
#include <sys/socketvar.h>
#include <sys/socket.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <dev/kttcpio.h>
static int kttcp_send(struct proc *p, struct kttcp_io_args *);
static int kttcp_recv(struct proc *p, struct kttcp_io_args *);
static int kttcp_sosend(struct socket *, unsigned long long,
unsigned long long *, struct proc *, int);
static int kttcp_soreceive(struct socket *, unsigned long long,
unsigned long long *, struct proc *, int *);
void kttcpattach(int);
cdev_decl(kttcp);
void
kttcpattach(int count)
{
/* Do nothing. */
}
int
kttcpopen(dev_t dev, int flags, int fmt, struct proc *p)
{
/* Always succeeds. */
return (0);
}
int
kttcpclose(dev_t dev, int flags, int fmt, struct proc *p)
{
/* Always succeeds. */
return (0);
}
int
kttcpioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
{
int error;
if ((flag & FWRITE) == 0)
return EPERM;
switch (cmd) {
case KTTCP_IO_SEND:
error = kttcp_send(p, (struct kttcp_io_args *) data);
break;
case KTTCP_IO_RECV:
error = kttcp_recv(p, (struct kttcp_io_args *) data);
break;
default:
return EINVAL;
}
return error;
}
static int
kttcp_send(struct proc *p, struct kttcp_io_args *kio)
{
struct file *fp;
int error;
struct timeval t0, t1;
unsigned long long len, done;
if (kio->kio_totalsize >= KTTCP_MAX_XMIT)
return EINVAL;
fp = fd_getfile(p->p_fd, kio->kio_socket);
if (fp == NULL)
return EBADF;
if (fp->f_type != DTYPE_SOCKET)
return EFTYPE;
len = kio->kio_totalsize;
microtime(&t0);
do {
error = kttcp_sosend((struct socket *)fp->f_data, len,
&done, p, 0);
len -= done;
} while (error == 0 && len > 0);
microtime(&t1);
if (error != 0)
return error;
timersub(&t1, &t0, &kio->kio_elapsed);
kio->kio_bytesdone = kio->kio_totalsize - len;
return 0;
}
static int
kttcp_recv(struct proc *p, struct kttcp_io_args *kio)
{
struct file *fp;
int error;
struct timeval t0, t1;
unsigned long long len, done;
if (kio->kio_totalsize > KTTCP_MAX_XMIT)
return EINVAL;
fp = fd_getfile(p->p_fd, kio->kio_socket);
if (fp == NULL || fp->f_type != DTYPE_SOCKET)
return EBADF;
len = kio->kio_totalsize;
microtime(&t0);
do {
error = kttcp_soreceive((struct socket *)fp->f_data,
len, &done, p, NULL);
len -= done;
} while (error == 0 && len > 0 && done > 0);
microtime(&t1);
if (error == EPIPE)
error = 0;
if (error != 0)
return error;
timersub(&t1, &t0, &kio->kio_elapsed);
kio->kio_bytesdone = kio->kio_totalsize - len;
return 0;
}
#define SBLOCKWAIT(f) (((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)
/*
* Slightly changed version of sosend()
*/
static int
kttcp_sosend(struct socket *so, unsigned long long slen,
unsigned long long *done, struct proc *p, int flags)
{
struct mbuf **mp, *m, *top;
long space, len, mlen;
int error, s, dontroute, atomic;
long long resid;
atomic = sosendallatonce(so);
resid = slen;
top = NULL;
/*
* In theory resid should be unsigned.
* However, space must be signed, as it might be less than 0
* if we over-committed, and we must use a signed comparison
* of space and resid. On the other hand, a negative resid
* causes us to loop sending 0-length segments to the protocol.
*/
if (resid < 0) {
error = EINVAL;
goto out;
}
dontroute =
(flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
(so->so_proto->pr_flags & PR_ATOMIC);
p->p_stats->p_ru.ru_msgsnd++;
#define snderr(errno) { error = errno; splx(s); goto release; }
restart:
if ((error = sblock(&so->so_snd, SBLOCKWAIT(flags))) != 0)
goto out;
do {
s = splsoftnet();
if (so->so_state & SS_CANTSENDMORE)
snderr(EPIPE);
if (so->so_error) {
error = so->so_error;
so->so_error = 0;
splx(s);
goto release;
}
if ((so->so_state & SS_ISCONNECTED) == 0) {
if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
if ((so->so_state & SS_ISCONFIRMING) == 0)
snderr(ENOTCONN);
} else
snderr(EDESTADDRREQ);
}
space = sbspace(&so->so_snd);
if (flags & MSG_OOB)
space += 1024;
if ((atomic && resid > so->so_snd.sb_hiwat))
snderr(EMSGSIZE);
if (space < resid && (atomic || space < so->so_snd.sb_lowat)) {
if (so->so_state & SS_NBIO)
snderr(EWOULDBLOCK);
sbunlock(&so->so_snd);
error = sbwait(&so->so_snd);
splx(s);
if (error)
goto out;
goto restart;
}
splx(s);
mp = &top;
do {
do {
if (top == 0) {
MGETHDR(m, M_WAIT, MT_DATA);
mlen = MHLEN;
m->m_pkthdr.len = 0;
m->m_pkthdr.rcvif = (struct ifnet *)0;
} else {
MGET(m, M_WAIT, MT_DATA);
mlen = MLEN;
}
if (resid >= MINCLSIZE && space >= MCLBYTES) {
MCLGET(m, M_WAIT);
if ((m->m_flags & M_EXT) == 0)
goto nopages;
mlen = MCLBYTES;
#ifdef MAPPED_MBUFS
len = lmin(MCLBYTES, resid);
#else
if (atomic && top == 0) {
len = lmin(MCLBYTES - max_hdr,
resid);
m->m_data += max_hdr;
} else
len = lmin(MCLBYTES, resid);
#endif
space -= len;
} else {
nopages:
len = lmin(lmin(mlen, resid), space);
space -= len;
/*
* For datagram protocols, leave room
* for protocol headers in first mbuf.
*/
if (atomic && top == 0 && len < mlen)
MH_ALIGN(m, len);
}
resid -= len;
m->m_len = len;
*mp = m;
top->m_pkthdr.len += len;
if (error)
goto release;
mp = &m->m_next;
if (resid <= 0) {
if (flags & MSG_EOR)
top->m_flags |= M_EOR;
break;
}
} while (space > 0 && atomic);
s = splsoftnet();
if (so->so_state & SS_CANTSENDMORE)
snderr(EPIPE);
if (dontroute)
so->so_options |= SO_DONTROUTE;
if (resid > 0)
so->so_state |= SS_MORETOCOME;
error = (*so->so_proto->pr_usrreq)(so,
(flags & MSG_OOB) ? PRU_SENDOOB : PRU_SEND,
top, NULL, NULL, p);
if (dontroute)
so->so_options &= ~SO_DONTROUTE;
if (resid > 0)
so->so_state &= ~SS_MORETOCOME;
splx(s);
top = 0;
mp = &top;
if (error)
goto release;
} while (resid && space > 0);
} while (resid);
release:
sbunlock(&so->so_snd);
out:
if (top)
m_freem(top);
*done = slen - resid;
#if 0
printf("sosend: error %d slen %llu resid %lld\n", error, slen, resid);
#endif
return (error);
}
static int
kttcp_soreceive(struct socket *so, unsigned long long slen,
unsigned long long *done, struct proc *p, int *flagsp)
{
struct mbuf *m, **mp;
int flags, len, error, s, offset, moff, type;
long long orig_resid, resid;
struct protosw *pr;
struct mbuf *nextrecord;
pr = so->so_proto;
mp = NULL;
type = 0;
resid = orig_resid = slen;
if (flagsp)
flags = *flagsp &~ MSG_EOR;
else
flags = 0;
if (flags & MSG_OOB) {
m = m_get(M_WAIT, MT_DATA);
error = (*pr->pr_usrreq)(so, PRU_RCVOOB, m,
(struct mbuf *)(long)(flags & MSG_PEEK), (struct mbuf *)0,
(struct proc *)0);
if (error)
goto bad;
do {
resid -= min(resid, m->m_len);
m = m_free(m);
} while (resid && error == 0 && m);
bad:
if (m)
m_freem(m);
return (error);
}
if (mp)
*mp = (struct mbuf *)0;
if (so->so_state & SS_ISCONFIRMING && resid)
(*pr->pr_usrreq)(so, PRU_RCVD, (struct mbuf *)0,
(struct mbuf *)0, (struct mbuf *)0, (struct proc *)0);
restart:
if ((error = sblock(&so->so_rcv, SBLOCKWAIT(flags))) != 0)
return (error);
s = splsoftnet();
m = so->so_rcv.sb_mb;
/*
* If we have less data than requested, block awaiting more
* (subject to any timeout) if:
* 1. the current count is less than the low water mark,
* 2. MSG_WAITALL is set, and it is possible to do the entire
* receive operation at once if we block (resid <= hiwat), or
* 3. MSG_DONTWAIT is not set.
* If MSG_WAITALL is set but resid is larger than the receive buffer,
* we have to do the receive in sections, and thus risk returning
* a short count if a timeout or signal occurs after we start.
*/
if (m == 0 || (((flags & MSG_DONTWAIT) == 0 &&
so->so_rcv.sb_cc < resid) &&
(so->so_rcv.sb_cc < so->so_rcv.sb_lowat ||
((flags & MSG_WAITALL) && resid <= so->so_rcv.sb_hiwat)) &&
m->m_nextpkt == 0 && (pr->pr_flags & PR_ATOMIC) == 0)) {
#ifdef DIAGNOSTIC
if (m == 0 && so->so_rcv.sb_cc)
panic("receive 1");
#endif
if (so->so_error) {
if (m)
goto dontblock;
error = so->so_error;
if ((flags & MSG_PEEK) == 0)
so->so_error = 0;
goto release;
}
if (so->so_state & SS_CANTRCVMORE) {
if (m)
goto dontblock;
else
goto release;
}
for (; m; m = m->m_next)
if (m->m_type == MT_OOBDATA || (m->m_flags & M_EOR)) {
m = so->so_rcv.sb_mb;
goto dontblock;
}
if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0 &&
(so->so_proto->pr_flags & PR_CONNREQUIRED)) {
error = ENOTCONN;
goto release;
}
if (resid == 0)
goto release;
if ((so->so_state & SS_NBIO) || (flags & MSG_DONTWAIT)) {
error = EWOULDBLOCK;
goto release;
}
sbunlock(&so->so_rcv);
error = sbwait(&so->so_rcv);
splx(s);
if (error)
return (error);
goto restart;
}
dontblock:
#ifdef notyet /* XXXX */
if (uio->uio_procp)
uio->uio_procp->p_stats->p_ru.ru_msgrcv++;
#endif
nextrecord = m->m_nextpkt;
if (pr->pr_flags & PR_ADDR) {
#ifdef DIAGNOSTIC
if (m->m_type != MT_SONAME)
panic("receive 1a");
#endif
orig_resid = 0;
if (flags & MSG_PEEK) {
m = m->m_next;
} else {
sbfree(&so->so_rcv, m);
MFREE(m, so->so_rcv.sb_mb);
m = so->so_rcv.sb_mb;
}
}
while (m && m->m_type == MT_CONTROL && error == 0) {
if (flags & MSG_PEEK) {
m = m->m_next;
} else {
sbfree(&so->so_rcv, m);
MFREE(m, so->so_rcv.sb_mb);
m = so->so_rcv.sb_mb;
}
}
if (m) {
if ((flags & MSG_PEEK) == 0)
m->m_nextpkt = nextrecord;
type = m->m_type;
if (type == MT_OOBDATA)
flags |= MSG_OOB;
}
moff = 0;
offset = 0;
while (m && resid > 0 && error == 0) {
if (m->m_type == MT_OOBDATA) {
if (type != MT_OOBDATA)
break;
} else if (type == MT_OOBDATA)
break;
#ifdef DIAGNOSTIC
else if (m->m_type != MT_DATA && m->m_type != MT_HEADER)
panic("receive 3");
#endif
so->so_state &= ~SS_RCVATMARK;
len = resid;
if (so->so_oobmark && len > so->so_oobmark - offset)
len = so->so_oobmark - offset;
if (len > m->m_len - moff)
len = m->m_len - moff;
/*
* If mp is set, just pass back the mbufs.
* Otherwise copy them out via the uio, then free.
* Sockbuf must be consistent here (points to current mbuf,
* it points to next record) when we drop priority;
* we must note any additions to the sockbuf when we
* block interrupts again.
*/
resid -= len;
if (len == m->m_len - moff) {
if (m->m_flags & M_EOR)
flags |= MSG_EOR;
if (flags & MSG_PEEK) {
m = m->m_next;
moff = 0;
} else {
nextrecord = m->m_nextpkt;
sbfree(&so->so_rcv, m);
if (mp) {
*mp = m;
mp = &m->m_next;
so->so_rcv.sb_mb = m = m->m_next;
*mp = (struct mbuf *)0;
} else {
MFREE(m, so->so_rcv.sb_mb);
m = so->so_rcv.sb_mb;
}
if (m)
m->m_nextpkt = nextrecord;
}
} else {
if (flags & MSG_PEEK)
moff += len;
else {
if (mp)
*mp = m_copym(m, 0, len, M_WAIT);
m->m_data += len;
m->m_len -= len;
so->so_rcv.sb_cc -= len;
}
}
if (so->so_oobmark) {
if ((flags & MSG_PEEK) == 0) {
so->so_oobmark -= len;
if (so->so_oobmark == 0) {
so->so_state |= SS_RCVATMARK;
break;
}
} else {
offset += len;
if (offset == so->so_oobmark)
break;
}
}
if (flags & MSG_EOR)
break;
/*
* If the MSG_WAITALL flag is set (for non-atomic socket),
* we must not quit until "uio->uio_resid == 0" or an error
* termination. If a signal/timeout occurs, return
* with a short count but without error.
* Keep sockbuf locked against other readers.
*/
while (flags & MSG_WAITALL && m == 0 && resid > 0 &&
!sosendallatonce(so) && !nextrecord) {
if (so->so_error || so->so_state & SS_CANTRCVMORE)
break;
error = sbwait(&so->so_rcv);
if (error) {
sbunlock(&so->so_rcv);
splx(s);
return (0);
}
if ((m = so->so_rcv.sb_mb) != NULL)
nextrecord = m->m_nextpkt;
}
}
if (m && pr->pr_flags & PR_ATOMIC) {
flags |= MSG_TRUNC;
if ((flags & MSG_PEEK) == 0)
(void) sbdroprecord(&so->so_rcv);
}
if ((flags & MSG_PEEK) == 0) {
if (m == 0)
so->so_rcv.sb_mb = nextrecord;
if (pr->pr_flags & PR_WANTRCVD && so->so_pcb)
(*pr->pr_usrreq)(so, PRU_RCVD, (struct mbuf *)0,
(struct mbuf *)(long)flags, (struct mbuf *)0,
(struct proc *)0);
}
if (orig_resid == resid && orig_resid &&
(flags & MSG_EOR) == 0 && (so->so_state & SS_CANTRCVMORE) == 0) {
sbunlock(&so->so_rcv);
splx(s);
goto restart;
}
if (flagsp)
*flagsp |= flags;
release:
sbunlock(&so->so_rcv);
splx(s);
*done = slen - resid;
#if 0
printf("soreceive: error %d slen %llu resid %lld\n", error, slen, resid);
#endif
return (error);
}

58
sys/dev/kttcpio.h Normal file
View File

@ -0,0 +1,58 @@
/* $NetBSD: kttcpio.h,v 1.1 2002/06/28 23:27:14 thorpej Exp $ */
/*
* Copyright (c) 2002 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Frank van der Linden and Jason R. Thorpe for
* Wasabi Systems, Inc.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
* 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.
*/
#ifndef _DEV_KTTCPIO_H_
#define _DEV_KTTCPIO_H_
#include <sys/ioccom.h>
#include <sys/time.h>
struct kttcp_io_args {
unsigned long long kio_totalsize;/* i/o total size (IN) */
unsigned long long kio_bytesdone;/* i/o actually completed (OUT) */
struct timeval kio_elapsed; /* elapsed time (OUT) */
int kio_socket; /* socket to use for i/o (IN) */
int kio_protovers; /* KTTCP protocol version */
};
#define KTTCP_IO_SEND _IOWR('K', 0, struct kttcp_io_args)
#define KTTCP_IO_RECV _IOWR('K', 1, struct kttcp_io_args)
#define KTTCP_MAX_XMIT 0x7fffffffLL /* XXX can't handle > 31 bits */
#endif /* _DEV_KTTCPIO_H_ */