In random order:
In random order:

* make the code compile with WARNS=5 (at least on i386), mostly
  by adding 'const' specifier and replacing "void *" with "char *"
  in places where pointer arithmetic was used.
  This also spotted a few places where invalid tests (e.g. uint < 0)
  were used.

* support ranges in "list" and "show" commands. Now you can say

        ipfw show 100-1000 4000-8000

  which is very convenient when you have large rulesets.

* implement comments in ipfw commands. These are implemented in the
  kernel as O_NOP commands (which always match) whose body contains
  the comment string. In userland, a comment is a C++-style comment:

        ipfw add allow ip from me to any // i can talk to everybody

  The choice of '//' versus '#' is somewhat arbitrary, but because
  the preprocessor/readfile part of ipfw used to strip away '#',
  I did not want to change this behaviour.

  If a rule only contains a comment

        ipfw add 1000 // this rule is just a comment

  then it is stored as a 'count' rule (this is also to remind
  the user that scanning through a rule is expensive).

* improve handling of flags (still to be completed).
  ipfw_main() was written thinking of 'one rule per ipfw invocation',
  and so flags are set and never cleared. With readfile/preprocessor
  support, this changes and certain flags should be reset on each
  line. For the time being, only fix handling of '-a' which
  differentiates the "list" and "show" commands.

* rework the preprocessor support -- ipfw_main() already had most
  of the parsing code, so i have moved in there the only missing
  bit (stripping away '#' and comments) and removed the parsing
  from ipfw_readfile().
  Also, add some more options (such as -c, -N, -S) to the readfile
  section.

MFC after: 3 days

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase