ebtables: Review match/target lookup

Since ebtables does not indicate extension use on commandline via '-m'
flag as in iptables, loading of matches has to happen prior to
commandline parsing. While parsing, the right extension is searched for
unknown parameters by passing it to its 'parse' callback and checking if
it succeeds. As an unavoidable side-effect, custom data in
xtables_targets objects is being altered if the extension parser
succeeds.

If called multiple times, do_commandeb() leaks memory and fixing this
requires to properly treat the above quirk:

* Load extensions just once at program startup, thereby reusing the
  existing ones for several calls of do_commandeb().

* In ebt_cs_clean(), don't free memory which is being reused. Instead
  reinit custom extension data if it was used in current do_commandeb()
  call (i.e., it is contained in cs->match_list).

On the other hand, target lookup in command_jump() can be simplified a
lot: The only target it may have loaded is 'standard', so just load that
at as well at program startup and reduce command_jump() to a simple
linked list search. Since 'standard' target does not prove a 'parse'
callback, a check is necessary when parsing target options.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

0 files changed, 0 insertions, 0 deletions