acg@pucc-h (Schwab) (05/25/84)
Description:
If a local network interface has an hlen of 0, the routines
in if_ubainit() allocate spurious pages and the if_rubaget()
routine will exchange the wrong page when handling a packet
greater than 1024 bytes long.
Repeat-By:
The pcl-11 is such a device. If you raise the mtu on the
device from the default 1006 to anything greater than
1024, your network will be unusable.
Fix:
The following diff's fix the extraneous page allocations and
the problems in if_rubaget().
- Jeff Schwab
<jrs@purdue, ...pur-ee!pucc-h:acg>
---- if_ubainit() ------
register caddr_t cp;
int i, ncl;
+ #ifdef PUCC
+ ncl = clrnd(nmr + (hlen? CLSIZE: 0)) / CLSIZE;
+ #else PUCC
ncl = clrnd(nmr + CLSIZE) / CLSIZE;
+ #endif PUCC
if (ifu->ifu_r.ifrw_addr)
+ #ifdef PUCC
+ cp = ifu->ifu_r.ifrw_addr - (hlen? (CLBYTES - hlen): 0);
+ #else PUCC
cp = ifu->ifu_r.ifrw_addr - (CLBYTES - hlen);
+ #endif PUCC
else {
cp = m_clalloc(2 * ncl, MPG_SPACE);
if (cp == 0)
return (0);
+ #ifdef PUCC
+ ifu->ifu_r.ifrw_addr = cp + (hlen? (CLBYTES - hlen): 0);
+ #else PUCC
ifu->ifu_r.ifrw_addr = cp + CLBYTES - hlen;
+ #endif PUCC
ifu->ifu_w.ifrw_addr = ifu->ifu_r.ifrw_addr + ncl * CLBYTES;
------- if_rubaget() -------
ppte = &Mbmap[mtocl(p)*CLSIZE];
x = btop(cp - ifu->ifu_r.ifrw_addr);
ip = (int *)&ifu->ifu_r.ifrw_mr[x];
+ #ifdef PUCC
+ if (ifu->ifu_hlen == 0) {
+ ip--;
+ }
+ #endif PUCC
for (i = 0; i < CLSIZE; i++) {
struct pte t;
t = *ppte; *ppte++ = *cpte; *cpte = t;