Receive packets in a small pieces (NB_SORECEIVE_CHUNK), so TCP slowstart will
get its ACKs faster. From Darwin via FreeBSD. XXX I don't have any idea if this is useful or reasonable, but it looks XXX sane and the code works. "Remove if found nonuseful."
This commit is contained in:
jdolecek
parent
1ebbd9b463
commit
78b50cb215
@ -1,4 +1,4 @@
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/* $NetBSD: smb_trantcp.c,v 1.10 2003/02/26 19:31:33 jdolecek Exp $ */
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/* $NetBSD: smb_trantcp.c,v 1.11 2003/03/24 18:08:51 jdolecek Exp $ */
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/*
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* Copyright (c) 2000-2001 Boris Popov
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@ -31,11 +31,11 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* FreeBSD: src/sys/netsmb/smb_trantcp.c,v 1.4 2001/12/02 08:47:29 bp Exp
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* FreeBSD: src/sys/netsmb/smb_trantcp.c,v 1.17 2003/02/19 05:47:38 imp Exp
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: smb_trantcp.c,v 1.10 2003/02/26 19:31:33 jdolecek Exp $");
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__KERNEL_RCSID(0, "$NetBSD: smb_trantcp.c,v 1.11 2003/03/24 18:08:51 jdolecek Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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@ -444,9 +444,9 @@ nbssn_recv(struct nbpcb *nbp, struct mbuf **mpp, int *lenp,
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{
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struct socket *so = nbp->nbp_tso;
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struct uio auio;
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struct mbuf *m;
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struct mbuf *m, *tm, *im;
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u_int8_t rpcode;
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int len;
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int len, resid;
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int error, rcvflg;
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if (so == NULL)
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@ -454,8 +454,12 @@ nbssn_recv(struct nbpcb *nbp, struct mbuf **mpp, int *lenp,
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if (mpp)
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*mpp = NULL;
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m = NULL;
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for(;;) {
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m = NULL;
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/*
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* Poll for a response header.
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* If we don't have one waiting, return.
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*/
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error = nbssn_recvhdr(nbp, &len, &rpcode, MSG_DONTWAIT, p);
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if (so->so_state &
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(SS_ISDISCONNECTING | SS_ISDISCONNECTED | SS_CANTRCVMORE)) {
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@ -467,39 +471,82 @@ nbssn_recv(struct nbpcb *nbp, struct mbuf **mpp, int *lenp,
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return error;
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if (len == 0 && nbp->nbp_state != NBST_SESSION)
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break;
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/* no data, try again */
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if (rpcode == NB_SSN_KEEPALIVE)
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continue;
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bzero(&auio, sizeof(auio));
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auio.uio_resid = len;
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auio.uio_procp = p;
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do {
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/*
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* Loop, blocking, for data following the response header.
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*
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* Note that we can't simply block here with MSG_WAITALL for the
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* entire response size, as it may be larger than the TCP
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* slow-start window that the sender employs. This will result
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* in the sender stalling until the delayed ACK is sent, then
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* resuming slow-start, resulting in very poor performance.
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*
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* Instead, we never request more than NB_SORECEIVE_CHUNK
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* bytes at a time, resulting in an ack being pushed by
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* the TCP code at the completion of each call.
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*/
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resid = len;
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while (resid > 0) {
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tm = NULL;
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rcvflg = MSG_WAITALL;
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#ifndef __NetBSD__
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error = so->so_proto->pr_usrreqs->pru_soreceive
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(so, (struct sockaddr **)NULL,
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&auio, &m, (struct mbuf **)NULL, &rcvflg);
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bzero(&auio, sizeof(auio));
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auio.uio_resid = min(resid, NB_SORECEIVE_CHUNK);
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auio.uio_procp = p;
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resid -= auio.uio_resid;
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/*
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* Spin until we have collected everything in
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* this chunk.
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*/
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do {
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rcvflg = MSG_WAITALL;
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#ifdef __NetBSD__
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error = (*so->so_receive)(so, (struct mbuf **)0,
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&auio, &tm, (struct mbuf **)NULL,
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&rcvflg);
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#else
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error = (*so->so_receive)(so, (struct mbuf **)0,
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&auio, &m,
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(struct mbuf **)NULL,
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&rcvflg);
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error = so->so_proto->pr_usrreqs->pru_soreceive
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(so, (struct sockaddr **)NULL,
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&auio, &tm, (struct mbuf **)NULL, &rcvflg);
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#endif
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} while (error == EWOULDBLOCK || error == EINTR ||
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} while (error == EWOULDBLOCK || error == EINTR ||
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error == ERESTART);
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if (error)
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break;
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if (auio.uio_resid > 0) {
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SMBERROR("packet is shorter than expected\n");
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error = EPIPE;
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break;
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if (error)
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goto out;
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/* short return guarantees unhappiness */
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if (auio.uio_resid > 0) {
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SMBERROR("packet is shorter than expected\n");
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error = EPIPE;
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goto out;
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}
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/* append received chunk to previous chunk(s) */
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if (m == NULL) {
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m = tm;
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} else {
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/*
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* Just glue the new chain on the end.
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* Consumer will pullup as required.
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*/
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for (im = m; im->m_next != NULL; im = im->m_next)
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;
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im->m_next = tm;
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}
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}
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/* got a session/message packet? */
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if (nbp->nbp_state == NBST_SESSION &&
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rpcode == NB_SSN_MESSAGE)
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break;
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/* drop packet and try for another */
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NBDEBUG("non-session packet %x\n", rpcode);
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if (m)
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if (m) {
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m_freem(m);
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m = NULL;
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}
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}
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out:
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if (error) {
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if (m)
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m_freem(m);
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@ -1,4 +1,4 @@
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/* $NetBSD: smb_trantcp.h,v 1.3 2003/02/21 20:12:05 jdolecek Exp $ */
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/* $NetBSD: smb_trantcp.h,v 1.4 2003/03/24 18:08:51 jdolecek Exp $ */
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/*
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* Copyright (c) 2000-2001, Boris Popov
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@ -31,7 +31,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* FreeBSD: src/sys/netsmb/smb_trantcp.h,v 1.2 2001/12/10 08:09:49 obrien Exp
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* FreeBSD: src/sys/netsmb/smb_trantcp.h,v 1.3 2002/09/18 07:38:10 bp Exp
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*/
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#ifndef _NETSMB_SMB_TRANTCP_H_
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#define _NETSMB_SMB_TRANTCP_H_
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@ -84,6 +84,14 @@ struct nbpcb {
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#define NB_SNDTIMEO (5 * hz)
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#define NB_RCVTIMEO (5 * hz)
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/*
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* TCP slowstart presents a problem in conjunction with large
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* reads. To ensure a steady stream of ACKs while reading using
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* large transaction sizes, we call soreceive() with a smaller
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* buffer size. See nbssn_recv().
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*/
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#define NB_SORECEIVE_CHUNK (8 * 1024)
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extern struct smb_tran_desc smb_tran_nbtcp_desc;
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#endif /* _KERNEL */
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