/*
 *	BIRD -- Configuration Parser Top
 *
 *	(c) 1998--2000 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

/**
 * DOC: Parser
 *
 * Both the configuration and CLI commands are analysed using a syntax
 * driven parser generated by the |bison| tool from a grammar which
 * is constructed from information gathered from grammar snippets by
 * the |gen_parser.m4| script.
 *
 * Grammar snippets are files (usually with extension |.Y|) contributed
 * by various BIRD modules to provide information about syntax of their
 * configuration and their CLI commands. Each snipped consists of several
 * section, each of them starting with a special keyword: |CF_HDR| for
 * a list of |#include| directives needed by the C code, |CF_DEFINES|
 * for a list of C declarations, |CF_DECLS| for |bison| declarations
 * including keyword definitions specified as |CF_KEYWORDS|, |CF_GRAMMAR|
 * for the grammar rules, |CF_CODE| for auxillary C code and finally
 * |CF_END| at the end of the snippet.
 *
 * To create references between the snippets, it's possible to define
 * multi-part rules by utilizing the |CF_ADDTO| macro which adds a new
 * alternative to a multi-part rule.
 *
 * CLI commands are defined using a |CF_CLI| macro. Its parameters are:
 * the list of keywords determining the command, the list of paramaters,
 * help text for the parameters and help text for the command.
 *
 * Values of |enum| filter types can be defined using |CF_ENUM| with
 * the following parameters: name of filter type, prefix common for all
 * literals of this type, names of all the possible values.
 */

CF_HDR

#include "nest/bird.h"
#include "conf/conf.h"
#include "lib/resource.h"
#include "lib/socket.h"
#include "lib/timer.h"
#include "lib/string.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "nest/route.h"
#include "nest/cli.h"
#include "filter/filter.h"

/* FIXME: Turn on YYERROR_VERBOSE and work around lots of bison bugs? */

CF_DECLS

%union {
  int i;
  u32 i32;
  ip_addr a;
  struct symbol *s;
  char *t;
  struct rtable_config *r;
  struct f_inst *x;
  struct filter *f;
  struct f_tree *e;
  struct f_val v;
  struct f_path_mask *h;
  struct password_item *p;
  struct rt_show_data *ra;
  void *g;
  bird_clock_t time;
  struct prefix px;
}

%token END CLI_MARKER INVALID_TOKEN
%token GEQ LEQ NEQ AND OR
%token <i> NUM ENUM
%token <i32> RTRID
%token <a> IPA
%token <s> SYM
%token <t> TEXT

%type <i> expr bool pxlen
%type <time> datetime
%type <a> ipa
%type <px> prefix prefix_or_ipa

%nonassoc PREFIX_DUMMY
%nonassoc '=' '<' '>' '~' '.' GEQ LEQ NEQ AND OR
%left '+' '-'
%left '*' '/' '%'
%left '!'

CF_KEYWORDS(DEFINE, ON, OFF, YES, NO)

CF_GRAMMAR

/* Basic config file structure */

config: conf_entries END { return 0; }
 | CLI_MARKER cli_cmd { return 0; }
 ;

conf_entries:
   /* EMPTY */
 | conf_entries conf
 ;

CF_ADDTO(conf, ';')

/* Constant expressions */

expr:
   NUM
 | '(' term ')' { $$ = f_eval_int($2); }
 | SYM { if ($1->class != SYM_NUMBER) cf_error("Number expected"); else $$ = $1->aux; }
 ;

CF_ADDTO(conf, definition)
definition:
   DEFINE SYM '=' expr ';' {
     cf_define_symbol($2, SYM_NUMBER, NULL);
     $2->aux = $4;
   }
 | DEFINE SYM '=' IPA ';' {
     cf_define_symbol($2, SYM_IPA, cfg_alloc(sizeof(ip_addr)));
     *(ip_addr *)$2->def = $4;
   }
 ;

/* Switches */

bool:
   expr {$$ = !!$1; }
 | ON { $$ = 1; }
 | YES { $$ = 1; }
 | OFF { $$ = 0; }
 | NO { $$ = 0; }
 | /* Silence means agreement */ { $$ = 1; }
 ;

/* Addresses, prefixes and netmasks */

ipa:
   IPA
 | SYM {
     if ($1->class != SYM_IPA) cf_error("IP address expected");
     $$ = *(ip_addr *)$1->def;
   }
 ;

prefix:
   ipa pxlen {
     if (!ip_is_prefix($1, $2)) cf_error("Invalid prefix");
     $$.addr = $1; $$.len = $2;
   }
 ;

prefix_or_ipa:
   prefix
 | ipa { $$.addr = $1; $$.len = BITS_PER_IP_ADDRESS; }
 ;

pxlen:
   '/' expr {
     if ($2 < 0 || $2 > BITS_PER_IP_ADDRESS) cf_error("Invalid prefix length %d", $2);
     $$ = $2;
   }
 | ':' ipa {
     $$ = ipa_mklen($2);
     if ($$ < 0) cf_error("Invalid netmask %I", $2);
   }
 ;

datetime:
   TEXT {
     $$ = tm_parse_date($1);
     if (!$$)
       cf_error("Invalid date");
   }
 ;

CF_CODE

CF_END