pf: ugly error message when probability value out of range.

[Thomas Pfaff]

When specifying a probability attribute on a rule and the value is out of
range, pfctl reports the problem using the internal probability value, an
unsigned greater than UINT_MAX, rather than what you actually specified.

The accepted range is either a number between 0 and 1 or between 0 and 100
if followed by a % character (to specify the value in percent).

The pfctl rule output already display the probability value in percent:

    # pfctl -sr | grep prob
    pass in on em0 inet proto icmp all keep state probability 50%

so I think the error message should contain the value in percent also.

Below transcript is using current pfctl and patched pfctl (diff below):

    # grep prob pf.conf
    pass in on $int_if inet proto icmp all probability 1.1
    # pfctl -f pf.conf
    pf.conf:11: invalid probability: 4724464025.000000
    pfctl: Syntax error in config file: pf rules not loaded
    # /usr/src/sbin/pfctl/obj/pfctl -f pf.conf
    pf.conf:11: invalid probability: 1.1 (110%)
    pfctl: Syntax error in config file: pf rules not loaded
    #

Maybe something like this?

Index: parse.y
===================================================================
RCS file: /cvs/src/sbin/pfctl/parse.y,v
retrieving revision 1.594
diff -u -p -r1.594 parse.y
--- parse.y     24 Sep 2010 09:17:46 -0000      1.594
+++ parse.y     13 Dec 2010 16:28:43 -0000
@@ -2208,7 +2208,8 @@ filter_opt        : USER uids {
 
                        p = floor($2 * UINT_MAX + 0.5);
                        if (p < 0.0 || p > UINT_MAX) {
-                               yyerror("invalid probability: %lf", p);
+                               yyerror("invalid probability: %g (%g%%)", $2,
+                                   $2 * 100);
                                YYERROR;
                        }
                        filter_opts.prob = (u_int32_t)p;