Problem with 3c905c and boopd under Debian/Gnu Linux v 3.0

[Martin D. Weinberg]

Problem:

        Attempting to use grub as a network boot loader installed in the MBR of 
a local
        disk yielded endless messages of the form:

        ALERT: got a fragmented packet - reconfigure your server

Hardware & OS:

        Server: Debian/GNU Linux 3.0 distribution 
        Node/client: Dual Athlon mainboard (Tyan Tiger MPX with 3c905C onboard)

Diagnosis:

        It appears that the bootp is sending too large a packet for the MTU 
size of
        1500.  And, I think, that the driver can not handle fragments (?)

Fix:

        I changed the dhcp discocver and request sizes in netboot/main.c and now
        everything is working fine.  The sizes were based on an older version of
        grub.  This will no doubt break some other fix that motivated an 
increased
        request size.  But I am not aware the issues there.  I notice that this 
will
        fix problems that other users have posted to the grub newsgroup that I 
found
        in the archive.

Patch:

        This documents the changes I made to main.c.

--- main.c      Tue May  7 11:36:22 2002
+++ main.c.orig Tue May  7 11:35:34 2002
@@ -80,7 +80,8 @@
 static const unsigned char dhcpdiscover[] =
 {
   RFC2132_MSG_TYPE, 1, DHCPDISCOVER,   
-  RFC2132_MAX_SIZE, 2, 2, 64,
+  RFC2132_MAX_SIZE,2,  /* request as much as we can */
+  ETH_MAX_MTU / 256, ETH_MAX_MTU % 256,
   RFC2132_PARAM_LIST, 4, RFC1533_NETMASK, RFC1533_GATEWAY,
   RFC1533_HOSTNAME, RFC1533_EXTENSIONPATH
 };
@@ -90,7 +91,8 @@
   RFC2132_MSG_TYPE, 1, DHCPREQUEST,
   RFC2132_SRV_ID, 4, 0, 0, 0, 0,
   RFC2132_REQ_ADDR, 4, 0, 0, 0, 0,
-  RFC2132_MAX_SIZE, 2, 2, 64,
+  RFC2132_MAX_SIZE, 2, /* request as much as we can */
+  ETH_MAX_MTU / 256, ETH_MAX_MTU % 256,
   /* request parameters */
   RFC2132_PARAM_LIST,
   /* 4 standard + 2 vendortags */



-- 
Martin Weinberg                      Phone: (413) 545-3821
Dept. of Astronomy                   FAX:   (413) 545-2117/0648
530 Graduate Research Tower          address@hidden
University of Massachusetts          http://www.astro.umass.edu/~weinberg/
Amherst, MA  01003-4525