BIGPHYSAREA Gigabit Driver

                      S. Durkin


My gigabit driver is based on the fact that all incoming packets in
any ethernet driver are passed to the kernel through a single 
routine netif_rx. I hijack this routine. As one can see in 
the routine /bigphysarea_xxxx/d550/dl2x.c the added code is:


// durkin hook kludge
extern int netif_rx_hook_2(struct sk_buff *skb);
extern int netif_rx_hook_3(struct sk_buff *skb);

// durkin hook kludge
			// netif_rx(skb);
			if(strcmp(dev->name,"eth2")==0)netif_rx_hook_2(skb);	     /* send it up */
			if(strcmp(dev->name,"eth3")==0)netif_rx_hook_3(skb);	     /* send it up */


The routines netif_rx_hook_x write the incoming packets to bigphysarea memory.
I have written a character driver to retreive these packets from this memory.


SETUP:

I assume that the D-Link ethernet cards are eth2,eth3. If not the 
code has to be modified (easy).

First set up the ethernet scripts to a local area network.



/etc/sysconfig/network-scripts/ifcfg-eth2

DEVICE=eth2
USERCTL=no
ONBOOT=no
BOOTPROTO=none
IPADDR=10.0.0.1
BROADCAST=10.0.0.255
NETWORK=10.0.0.0
NETMASK=255.255.255.0
TYPE=Ethernet
PEERDNS=no

/etc/sysconfig/network-scripts/ifcfg-eth3

DEVICE=eth3
USERCTL=no
ONBOOT=no
BOOTPROTO=none
IPADDR=10.0.0.2
BROADCAST=10.0.0.255
NETWORK=10.0.0.0
NETMASK=255.255.255.0
TYPE=Ethernet
PEERDNS=no


One now needs to make the character devices:

mknod 232 0 c /dev/schar2
mknod 232 0 c /dev/schar3

You should change the permission on these devices so a 
standard user can access them.

ls -all /dev/schar2
crwxrwxrwx    1 root     root     232,   0 Mar  9 10:40 /dev/schar2
ls -all /dev/schar3
crwxrwxrwx    1 root     root     233,   0 Mar  9 10:40 /dev/schar3


Compile the driver.

/bigphysarea_xxxx/d550/make
/bigphysarea_xxxx/eth_hook_2/make
/bigphysarea_xxxx/eth_hook_3/make


Loading the driver.

/bigphysarea_xxxx/ethreset


Checking the driver loaded.

/sbin/lsmod

dl2x                   14660   2
eth_hook_3              6944   0  [dl2x]
eth_hook_2              7584   0  [dl2x]


You can check that eth_hook_2 and eth_hook_3 grabbed allocated
memory.

cat /proc/bigphysarea

Big physical area, size 64000 kB
                       free list:             used list:
number of blocks:             1                      2
size of largest block:    56000 kB                4000 kB
total:                    56000 kB                8000 kB


One can also check ethnet packets via /sbin/ifconfig.

/sbin/ifconfig


eth2      Link encap:Ethernet  HWaddr 00:0D:88:B5:86:AC
          inet addr:10.0.0.1  Bcast:10.0.0.1  Mask:255.255.255.0
          UP BROADCAST RUNNING NOARP PROMISC MULTICAST  MTU:9000  Metric:1
          RX packets:3 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:180 (180.0 b)  TX bytes:0 (0.0 b)
          Interrupt:26 Base address:0xc00

 eth3      Link encap:Ethernet  HWaddr 00:0D:88:B5:86:AF
          inet addr:10.0.0.2  Bcast:10.0.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING NOARP PROMISC MULTICAST  MTU:9000  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:0 (0.0 b)  TX bytes:180 (180.0 b)
          Interrupt:24 Base address:0x2800


I have also added proc files for the character devices eth_hook_2 and eth_hook_3. Just type.

cat /proc/sys/dev/schar/2  or cat /proc/sys/dev/schar/3

GIGABIT DRIVER ETH2
 
 RECEIVE:
  recieve               3
  read                  0
  nleft                 3
  bytes                         000000192
  allowed                       004096000
 
 TRANSMIT:
  transmit                      0
  bytes                         000000000
 
 ERROR STATISTICS:
  loop          0
  counter               0
  overwrite             0
  flag                  0
  oversize              0

At this point you can be very confident that the drivers
are loaded and working.

TUNING DRIVERS

The amount of memory allocated by the drivers can be modified in the 
eth_hook_x drivers. One line of the code needs to be modified.

               #define MMT_PAGES_2 1000
               #define MMT_PAGESIZE_2 4096 

Here I have allocated 4096x1000 bytes to the driver. In last years
test beam we allocated a full 1 gig of bigphysarea memory to the
driver.

TESTING DRIVERS

Attach a fiber cable between the two gigabit ethernet cards. Make 
sure the link lights turn on (the drivers must be loaded).

Routines to write, read and reset between the connected drivers can
be found in:

    http://www.physics.ohio-state.edu/~durkin/software/frank.tar


AUTO LOADING DRIVERS

Believe it or not we have been too lazy to do this to date. This is 
how one might do it though.

In the directory /etc/rc.d/init.d one needs to add the following 
script (name it eth_hook or something)..

#!/bin/sh
#
# chkconfig: 345 55 45
#
# Source function library.
. /etc/rc.d/init.d/functions

# See how we were called.
case "$1" in
  start)
        echo -n "Starting eth_hook drivers: "
        /root/bigphysarea_xxxx/ethreset
        echo eth_hook
        ;;
  stop)
        echo -n "Stopping eth_daemon: "
        .root/bigphysarea_xxxx/ethdown
        echo "eth_hook"
        ;;
  restart)
        $0 stop
        $0 start
        ;;
  *)
        echo "Usage: $0 {start|stop|restart}"
        exit 1
esac

exit 0

Once this script has been added one can use the standard system scripts
to add this to the startup programs.

             Hope this helps.

              Stan