Make ipfw tables use names as used-level identifier internally:

* Add namedobject set-aware api capable of searching/allocation objects by their name/idx.
* Switch tables code to use string ids for configuration tasks.
* Change locking model: most configuration changes are protected with UH lock, runtime-visible are protected with both locks.
* Reduce number of arguments passed to ipfw_table_add/del by using separate structure.
* Add internal V_fw_tables_sets tunable (set to 0) to prepare for set-aware tables (requires opcodes/client support)
* Implement typed table referencing (and tables are implicitly allocated with all state like radix ptrs on reference)
* Add "destroy" ipfw(8) using new IP_FW_DELOBJ opcode

Namedobj more detailed:
* Blackbox api providing methods to add/del/search/enumerate objects
* Statically-sized hashes for names/indexes
* Per-set bitmask to indicate free indexes
* Separate methods for index alloc/delete/resize

Basically, there should not be any user-visible changes except the following:
* reducing table_max is not supported
* flush & add change table type won't work if table is referenced

Sponsored by:	Yandex LLC
Add API to ease adding new algorithms/new tabletypes to ipfw.

Kernel-side changelog:
* Split general tables code and algorithm-specific table data.
  Current algorithms (IPv4/IPv6 radix and interface tables radix) moved to
  new ip_fw_table_algo.c file.
  Tables code now supports any algorithm implementing the following callbacks:
+struct table_algo {
+       char            name[64];
+       int             idx;
+       ta_init         *init;
+       ta_destroy      *destroy;
+       table_lookup_t  *lookup;
+       ta_prepare_add  *prepare_add;
+       ta_prepare_del  *prepare_del;
+       ta_add          *add;
+       ta_del          *del;
+       ta_flush_entry  *flush_entry;
+       ta_foreach      *foreach;
+       ta_dump_entry   *dump_entry;
+       ta_dump_xentry  *dump_xentry;
+};

* Change ->state, ->xstate, ->tabletype fields of ip_fw_chain to
   ->tablestate pointer (array of 32 bytes structures necessary for
   runtime lookups (can be probably shrinked to 16 bytes later):

   +struct table_info {
   +       table_lookup_t  *lookup;        /* Lookup function */
   +       void            *state;         /* Lookup radix/other structure */
   +       void            *xstate;        /* eXtended state */
   +       u_long          data;           /* Hints for given func */
   +};

* Add count method for namedobj instance to ease size calculations
* Bump ip_fw3 buffer in ipfw_clt 128->256 bytes.
* Improve bitmask resizing on tables_max change.
* Remove table numbers checking from most places.
* Fix wrong nesting in ipfw_rewrite_table_uidx().

* Add IP_FW_OBJ_LIST opcode (list all objects of given type, currently
    implemented for IPFW_OBJTYPE_TABLE).
* Add IP_FW_OBJ_LISTSIZE (get buffer size to hold IP_FW_OBJ_LIST data,
    currenly implemented for IPFW_OBJTYPE_TABLE).
* Add IP_FW_OBJ_INFO (requests info for one object of given type).

Some name changes:
s/ipfw_xtable_tlv/ipfw_obj_tlv/ (no table specifics)
s/ipfw_xtable_ntlv/ipfw_obj_ntlv/ (no table specifics)

Userland changes:
* Add do_set3() cmd to ipfw2 to ease dealing with op3-embeded opcodes.
* Add/improve support for destroy/info cmds.
Add ip_fw_algo.c to ipfw Makefile.
Move most of external table structures/functions to separate ip_fw_table.h
Move further to eliminate next pieces of number-assuming code inside tables.

Kernel changes:
* Add IP_FW_OBJ_FLUSH opcode (flush table based on its name/set)
* Add IP_FW_OBJ_DUMP opcode (dumps table data based on its names/set)
* Add IP_FW_OBJ_LISTSIZE / IP_FW_OBJ_LIST opcodes (get list of kernel tables)

Userland changes:
* move tables code to separate tables.c file
* get rid of tables_max
* switch "all"/list handling to new opcodes
Simplify opcode handling.

* Use one u16 from op3 header to implement opcode versioning.
* IP_FW_TABLE_XLIST has now 2 handlers, for ver.0 (old) and ver.1 (current).
* Every getsockopt request is now handled in ip_fw_table.c
* Rename new opcodes:
IP_FW_OBJ_DEL -> IP_FW_TABLE_XDESTROY
IP_FW_OBJ_LISTSIZE -> IP_FW_TABLES_XGETSIZE
IP_FW_OBJ_LIST -> IP_FW_TABLES_XLIST
IP_FW_OBJ_INFO -> IP_FW_TABLE_XINFO
IP_FW_OBJ_INFO -> IP_FW_TABLE_XFLUSH

* Add some docs about using given opcodes.
* Group some legacy opcode/handlers.
Remove unused ipfw_dump_xtable().
* Add IP_FW_TABLE_XCREATE / IP_FW_TABLE_XMODIFY opcodes.
* Add 'algoname' string to ipfw_xtable_info permitting to specify lookup
algoritm with parameters.
* Rework part of ipfw_rewrite_table_uidx()

Sponsored by:	Yandex LLC
Use different approach for filling large datasets to userspace:

Instead of trying to allocate bing contiguous chunk of memory,
use intermediate-sized (page size) buffer as sliding window
reducing number of sooptcopyout() calls to perform.

This reduces dump functions complexity and provides additional
layer of abstraction.

User-visible api consists of 2 functions:
ipfw_get_sopt_space() - gets contigious amount of storage (or NULL)
and
ipfw_get_sopt_header() - the same, but zeroes the rest of the buffer.
Suppord showing named tables in ipfw(8) rule listing.

Kernel changes:
* change base TLV header to be u64 (so size can be u32).
* Introduce ipfw_obj_ctlv generc container TLV.
* Add IP_FW_XGET opcode which is now used for atomic configuration
  retrieval. One can specify needed configuration pieces to retrieve
  via flags field. Currently supported are
  IPFW_CFG_GET_STATIC (static rules) and
  IPFW_CFG_GET_STATES (dynamic states).
  Other configuration pieces (tables, pipes, etc..) support is planned.

Userland changes:
* Switch ipfw(8) to use new IP_FW_XGET for rule listing.
* Split rule listing code get and show pieces.
* Make several steps forward towards libipfw:
  permit printing states and rules(paritally) to supplied buffer.
  do not die on malloc/kernel failure inside given printing functions.
  stop assuming cmdline_opts is global symbol.
Enable kernel-side rule filtering based on user request.
Make do_get3() function return real error.
* Add new IP_FW_XADD opcode which permits to
  a) specify table ids as names
  b) add multiple rules at once.
Partially convert current code for atomic addition of multiple rules.
Fully switch to named tables:

Kernel changes:
* Introduce ipfw_obj_tentry table entry structure to force u64 alignment.
* Support "update-on-existing-key" "add" bahavior (TEI_FLAGS_UPDATED).
* Use "subtype" field to distingush between IPv4 and IPv6 table records
  instead of previous hack.
* Add value type (vtype) field for kernel tables. Current types are
  number,ip and dscp
* Fix sets mask retrieval for old binaries
* Fix crash while using interface tables

Userland changes:
* Switch ipfw_table_handler() to use named-only tables.
* Add "table NAME create [type {cidr|iface|u32} [valtype {number|ip|dscp}] ..."
* Switch ipfw_table_handler to match_token()-based parser.
* Switch ipfw_sets_handler to use new ipfw_get_config() for mask  retrieval.
* Allow ipfw set X table ... syntax to permit using per-set table namespaces.
* Issue warning while requesting ruleset with new tables via legacy binary.
  Convert each unresolved table as table 65535 (which cannot be used normally).
* Perform s/^ipfw_// for add_table_entry, del_table_entry and flush_table since
  these are internal functions exported to keep legacy interface.
* Remove macro TABLE_SET. Operations with tables can be done in any set, the only
  thing net.inet.ip.fw.tables_sets affects is the set in which tables are looked
  up while binding them to the rule.
* Add "lookup" table functionality to permit userland entry lookups.
* Bump table dump format preserving old ABI.

Kernel size:
* Add IP_FW_TABLE_XFIND to handle "lookup" request from userland.
* Add ta_find_tentry() algorithm callbacks/handlers to support lookups.
* Fully switch to ipfw_obj_tentry for various table dumps:
  algorithms are now required to support the latest (ipfw_obj_tentry) entry
    dump format, the rest is handled by generic dump code.
  IP_FW_TABLE_XLIST opcode version bumped (0 -> 1).
* Eliminate legacy ta_dump_entry algo handler:
  dump_table_entry() converts data from current to legacy format.

Userland side:
* Add "lookup" table parameter.
* Change the way table type is guessed: call table_get_info() first,
  and check value for IPv4/IPv6 type IFF table does not exist.
* Fix table_get_list(): do more tries if supplied buffer is not enough.
* Sparate table_show_entry() from table_show_list().
* Prepare to pass other dynamic states via ipfw_dump_config()

Kernel changes:
* Change dump format for dynamic states:
  each state is now stored inside ipfw_obj_dyntlv
  last dynamic state is indicated by IPFW_DF_LAST flag
* Do not perform sooptcopyout() for !SOPT_GET requests.

Userland changes:
* Introduce foreach_state() function handler to ease work
  with different states passed by ipfw_dump_config().
* Use different rule structures in kernel/userland.
* Switch kernel to use per-cpu counters for rules.
* Keep ABI/API.

Kernel changes:
* Each rules is now exported as TLV with optional extenable
  counter block (ip_fW_bcounter for base one) and
  ip_fw_rule for rule&cmd data.
* Counters needs to be explicitly requested by IPFW_CFG_GET_COUNTERS flag.
* Separate counters from rules in kernel and clean up ip_fw a bit.
* Pack each rule in IPFW_TLV_RULE_ENT tlv to ease parsing.
* Introduce versioning in container TLV (may be needed in future).
* Fix ipfw_cfg_lheader broken u64 alignment.

Userland changes:
* Use set_mask from cfg header when requesting config
* Fix incorrect read accouting in ipfw_show_config()
* Use IPFW_RULE_NOOPT flag instead of playing with _pad
* Fix "ipfw -d list": do not print counters for dynamic states
* Some small fixes
* Reduce size of ipfw table entries for cidr/iface:

Since old structures had _value as the last field,
every table match required 3 cache lines instead of 2.
Fix this by
- using the fact that supplied masks are suplicated inside radix
- using lightweigth sa_in6 structure as key for IPv6

Before (amd64):
  sizeof(table_entry): 136
  sizeof(table_xentry): 160
After (amd64):
  sizeof(radix_cidr_entry): 120
  sizeof(radix_cidr_xentry): 128
  sizeof(radix_iface): 128

* Fix memory leak for table entry update
* Do some more sanity checks while deleting entry
* Do not store masks for host routes

Sponsored by:	Yandex LLC
* Require explicit table creation before use on kernel side.
* Add resize callbacks for upcoming table-based algorithms.

Kernel changes:
* s/ipfw_modify_table/ipfw_manage_table_ent/
* Simplify add_table_entry(): make table creation a separate piece of code.
  Do not perform creation if not in "compat" mode.
* Add ability to perform modification of algorithm state (like table resize).
  The following callbacks were added:
 - prepare_mod (allocate new state, without locks)
 - fill_mod (UH_WLOCK, copy old state to new one)
 - modify (UH_WLOCK + WLOCK, switch state)
 - flush_mod (no locks, flushes allocated data)
 Given callbacks are called if table modification has been requested by add or
   delete callbacks. Additional u64 tc->'flags' field was added to pass these
   requests.
* Change add/del table ent format: permit adding/removing multiple entries
   at once (only 1 supported at the moment).

Userland changes:
* Auto-create tables with warning
* Add generic ipfw interface tracking API
* Rewrite interface tables to use interface indexes

Kernel changes:
* Add generic interface tracking API:
 - ipfw_iface_ref (must call unlocked, performs lazy init if needed, allocates
  state & bumps ref)
 - ipfw_iface_add_ntfy(UH_WLOCK+WLOCK, links comsumer & runs its callback to
  update ifindex)
 - ipfw_iface_del_ntfy(UH_WLOCK+WLOCK, unlinks consumer)
 - ipfw_iface_unref(unlocked, drops reference)
Additionally, consumer callbacks are called in interface withdrawal/departure.

* Rewrite interface tables to use iface tracking API. Currently tables are
  implemented the following way:
  runtime data is stored as sorted array of {ifidx, val} for existing interfaces
  full data is stored inside namedobj instance (chained hashed table).

* Add IP_FW_XIFLIST opcode to dump status of tracked interfaces

* Pass @chain ptr to most non-locked algorithm callbacks:
  (prepare_add, prepare_del, flush_entry ..). This may be needed for better
  interaction of given algorithm an other ipfw subsystems

* Add optional "change_ti" algorithm handler to permit updating of
  cached table_info pointer (happens in case of table_max resize)

* Fix small bug in ipfw_list_tables()
* Add badd (insert into sorted array) and bdel (remove from sorted array) funcs

Userland changes:
* Add "iflist" cmd to print status of currently tracked interface
* Add stringnum_cmp for better interface/table names sorting