A-14 APPENDIX A: PACKET FILTER OPCODES, EXAMPLES, AND SYNTAX ERRORS

Table A-1 Possible Syntax Errors When Loading Packet Filters (continued)

Syntax Error

 

Description

 

 

 

 

Invalid

 

 

The number specified as an offset or literal is improperly

characters

 

formatted. Possible causes are 1) lack of white space setting

in number

 

 

 

 

 

off the number, and 2) invalid characters in the number.

 

 

 

 

Note: The radix of the number is determined by the first 1 or

 

 

 

 

2 characters of the number.

 

 

 

 

A number with a leading “0x” or “0X” is treated as

 

 

 

 

hexadecimal.

 

 

 

 

A number with a leading 0 is treated as octal.

 

 

 

 

All other numbers are treated as decimal.

 

 

 

Number

is too

The number specified as an offset or literal is too large.

large

 

 

 

An offset is limited to 1518 minus the size of the operand.

 

 

 

 

 

 

 

 

For example, the offset for pushField.b can be no more than

 

 

 

 

1517 and the offset for pushField.w no more than 1516.

 

 

 

 

A literal value is limited to the number of bytes in the

 

 

 

 

operand size (1, 2, 4, or 6).

 

 

 

Missing

open

The string specified does not have a starting quotation

quote

on

string

mark (").

 

 

 

 

 

 

 

String

is too

The string specified is too long. Strings are limited to 32

long

 

 

 

characters exclusive of the opening and closing quotation

 

 

 

 

 

 

 

 

marks.

 

 

 

Missing

close

The string specified does not have an ending quotation mark

quote

on

string

(").

 

 

 

 

 

 

 

Multiple

name

More than one name statement was found in the program.

statements

in

Only a single name statement is allowed.

program

 

 

 

 

 

 

Program

too

large

The program exceeds the maximum size allowed. The causes

 

 

 

 

of this error include a source definition exceeding 4096

 

 

 

 

bytes, a stored format exceeding 254 bytes, or a run-time

format exceeding 2048 bytes. All of these boundary conditions are checked when the filter is loaded. See Table 13-2 for more information on packet filter sizes.

Too many errors

-compilation aborted

The program contains an excessive number of errors. No further syntax errors will be reported. The program stops compiling when this condition occurs.

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3Com 2200 Characters of the number, Number with a leading 0x or 0X is treated as, Hexadecimal, Operand size 1, 2, 4, or