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A-10
A
A: P
PPENDIX
ACKET
Type Filter
Ethernet Type IPX
and Multicast Filter
Multiple
Destination
Address Filter
F
O
, E
ILTER
PCODES
XAMPLES
This filter operates on the type field of a frame. It allows packets to be
forwarded that are IP frames. To customize this filter to another type value,
change the literal value loaded in the
name
"Forward IP frames"
pushField.w
12
pushLiteral.w
0x0800
eq
This filter rejects frames that have either a Novell IPX Ethernet type field
(8134 hex) or a multicast destination address.
name
"Type > 900 or Multicast"
pushField.w
12
pushLiteral.w
0x900
gt
reject
pushLiteral.b
0x01
pushField.b
0
and
not
This filter operates on the destination address field of a frame. It allows
packets to be forwarded that are destined for one of four different stations.
To customize this filter to other destination stations, change the literal
values.
name
"Forward to four stations"
pushField.a
0
pushTop
pushTop
pushTop
pushLiteral.a
0x367002010203 # Load allowed destination
eq
accept
pushLiteral.a
0x468462236526 # Load allowed destination
eq
accept
pushLiteral.a
0x347872927352 # Load allowed destination
eq
accept
pushLiteral.a
0x080239572897 # Load allowed destination
eq
,
S
E
AND
YNTAX
RRORS
pushLiteral.w
# Get type field
# Load IP type value
# Check for match
# Get type field
# Push type value to test
# against
# Is type field > 900 (hex)?
# If yes: reject frame (done)
# Multicast bit is low-order bit
# Get 1st byte of destination
# Isolate multicast bit
# Top of stack 1 to accept,
# 0 to reject
# Get destination address
# Make 3 copies of address
#
#
# address
# Check for match
# Forward if valid address
# address
# Check for match
# Forward if valid address
# address
# Check for match
# Forward if valid address
# address
# Check for match
instruction.
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