giz@sequent.UUCP (03/19/84)
This article brings up the question of network devices that can handle packets of length >= 2K. Is there any such devices available? Also i'd like to point out that ethernet is spec'd not to handle packets of this length so you would have to have a device that can generate a large packet to be affected. Has anyone looked at typical net traffic to see how much a large packet feature would be used? -- Jim Chorn Sequent Computer Systems ...ogcvax!sequent!giz (503)627-9815
salkind%nyu@sri-unix.UUCP (03/20/84)
From: Lou Salkind <salkind@nyu>
Subject: a bug in if_uba.c (not that serious)
Index: sys/vaxif/if_uba. 4.2BSD
Description:
There are two problems in if_uba.c:if_wubaput:
(1) there is a superfluous instruction
(2) the variable x is used for two different purposes in if_wubaput.
This will cause transfers of two full clicks or more to fail.
(Luckily the network interfaces don't do this currently.)
Repeat-By:
Transfer 2K packets over your network device...
Fix:
The diff follows. Note all the routines assume hlen < PGSIZE
(a very reasonable assumption, but it should be noted).
*** /tmp/,RCSt1008503 Tue Mar 13 18:30:59 1984
--- /tmp/,RCSt2008503 Tue Mar 13 18:31:00 1984
***************
*** 1,3
/* if_uba.c 6.1 83/07/29 */
#include "../machine/pte.h"
--- 1,7 -----
+ #ifdef RCSIDENT
+ static char *rcsid = "$Header: /usr/sys/vaxif/RCS/if_uba.c,v 1.2 84/03/13 01:01:40 salkind Exp $";
+ #endif
+
/* if_uba.c 6.1 83/07/29 */
#include "../machine/pte.h"
***************
*** 31,36
* with the header, and nmr more UNIBUS map registers for i/o on the adapter,
* doing this twice: once for reading and once for writing. We also
* allocate page frames in the mbuffer pool for these pages.
*/
if_ubainit(ifu, uban, hlen, nmr)
register struct ifuba *ifu;
--- 35,41 -----
* with the header, and nmr more UNIBUS map registers for i/o on the adapter,
* doing this twice: once for reading and once for writing. We also
* allocate page frames in the mbuffer pool for these pages.
+ * NOTE IT IS IMPLICTLY ASSUMED THAT hlen < PGSIZE.
*/
if_ubainit(ifu, uban, hlen, nmr)
register struct ifuba *ifu;
***************
*** 198,204
register caddr_t cp, dp;
register int i;
int xswapd = 0;
! int x, cc;
cp = ifu->ifu_w.ifrw_addr;
while (m) {
--- 203,209 -----
register caddr_t cp, dp;
register int i;
int xswapd = 0;
! int x, cc, t;
cp = ifu->ifu_w.ifrw_addr;
while (m) {
***************
*** 234,240
cc = cp - ifu->ifu_w.ifrw_addr;
x = ((cc - ifu->ifu_hlen) + CLBYTES - 1) >> CLSHIFT;
ifu->ifu_xswapd &= ~xswapd;
- xswapd &= ~ifu->ifu_xswapd;
while (i = ffs(ifu->ifu_xswapd)) {
i--;
if (i >= x)
--- 239,244 -----
cc = cp - ifu->ifu_w.ifrw_addr;
x = ((cc - ifu->ifu_hlen) + CLBYTES - 1) >> CLSHIFT;
ifu->ifu_xswapd &= ~xswapd;
while (i = ffs(ifu->ifu_xswapd)) {
i--;
if (i >= x)
***************
*** 241,247
break;
ifu->ifu_xswapd &= ~(1<<i);
i *= CLSIZE;
! for (x = 0; x < CLSIZE; x++) {
ifu->ifu_w.ifrw_mr[i] = ifu->ifu_wmap[i];
i++;
}
--- 245,251 -----
break;
ifu->ifu_xswapd &= ~(1<<i);
i *= CLSIZE;
! for (t = 0; t < CLSIZE; t++) {
ifu->ifu_w.ifrw_mr[i] = ifu->ifu_wmap[i];
i++;
}