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bird/filter/config.Y
Pavel Machek 10a5360886 Filters now know type path. It is possible to declare variable of type 
path, but it is not possible to write constant of type path.

It should be possible to print paths and match them.
2000-04-12 13:31:39 +00:00

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/*
* BIRD - filters
*
* Copyright 1998,1999 Pavel Machek
*
* Can be freely distributed and used under the terms of the GNU GPL.
*
FIXME (nonurgent): define keyword
FIXME (for BGP): whole system of paths, path ~ string, path.prepend(), path.originate
FIXME: create community lists
FIXME: IP addresses in ipv6
FIXME: check messages for \n at the end
(1) Cesty
AS paths budtez interne reprezentovany stejne jako v BGP (viz RFC 1771),
to znamena jako posloupnost segmentu, z nichz kazdy je budto posloupnost nebo
mnozina cisel ASu. Na cestach nadefinuji nasledujici operace:
- zformatovani do stringu
- append dalsiho AS k ceste
Filtry by mely podporovat:
- operator pridani AS k ceste [bgppath_prepend]
- matchovani na pritomnost podposloupnosti v ceste (pricemz vyskytne-li
se tam mnozina, tak si ji lze predstavit prerovnanou v libovolnem
poradi)
- operator zjisteni delky cesty (pro vypocet metrik)
Byl bych rad, kdyby se samotne matchovaci funkce objevily v proto/bgp/attrs.c.
Jsou v sitove endianite. [lib/unaligned.h]
(2) Community-listy
posloupnost 32bitovych cisel s delkou.
Community list budiz interne reprezentovan jako posloupnost 32-bitovych cisel.
Filtry by se mely na communities divat jako na usporadane dvojice 16-bitovych
cisel (prvni je cislo AS, ktery community definoval, druhe pak community ID
v ramci AS) a melo by byt mozne definovat si konstanty typu community.
K dispozici by mely byt nasledujici operace:
- zjisteni pritomnosti community v listu [linearni pruchod]
- pridani community do listu [s kopii]
- odebrani community z listu [s kopii]
- zresetovani listu
Pro operace na cestach i na community listech by se mela pouzivat `teckova'
notace pouzita v mem puvodnim navrhu syntaxe.
*/
CF_HDR
#define P(a,b) ((a<<8) | b)
CF_DECLS
CF_KEYWORDS(FUNCTION, PRINT, PRINTN, UNSET, RETURN,
ACCEPT, REJECT, ERROR, QUITBIRD,
INT, BOOL, IP, PREFIX, PAIR, SET, STRING, BGPMASK, BGPPATH, CLIST,
IF, THEN, ELSE, CASE,
TRUE, FALSE,
FROM, GW, NET, MASK, SOURCE,
LEN,
DEFINED,
ADD, DELETE, CONTAINS, RESET,
APPEND, MATCH,
FILTER, WHERE)
%nonassoc THEN
%nonassoc ELSE
%type <x> term block cmds cmd function_body constant print_one print_list var_list var_listn dynamic_attr function_call
%type <f> filter filter_body where_filter
%type <i> type break_command pair
%type <e> set_item set_items switch_body
%type <v> set_atom prefix prefix_s ipa
%type <s> decls declsn one_decl function_params
%type <h> bgp_path
%type <i> bgp_one
CF_GRAMMAR
CF_ADDTO(conf, filter_def)
filter_def:
FILTER SYM { cf_push_scope( $2 ); } filter_body {
cf_define_symbol($2, SYM_FILTER, $4);
$4->name = $2->name;
DBG( "We have new filter defined (%s)\n", $2->name );
cf_pop_scope();
}
;
type:
INT { $$ = T_INT; }
| BOOL { $$ = T_BOOL; }
| IP { $$ = T_IP; }
| PREFIX { $$ = T_PREFIX; }
| PAIR { $$ = T_PAIR; }
| STRING { $$ = T_STRING; }
| BGPMASK { $$ = T_PATH_MASK; }
| BGPPATH { $$ = T_PATH; }
| CLIST { $$ = T_CLIST; }
| type SET {
switch ($1) {
default:
cf_error( "You can not create sets of this type\n" );
case T_INT: case T_IP: case T_PREFIX: case T_PAIR:
}
$$ = $1 | T_SET;
}
;
one_decl:
type SYM {
cf_define_symbol($2, SYM_VARIABLE | $1, NULL);
DBG( "New variable %s type %x\n", $2->name, $1 );
$2->aux = 0;
{
struct f_val * val;
val = cfg_alloc(sizeof(struct f_val));
val->type = $1;
$2->aux2 = val;
}
$$=$2;
}
;
/* Decls with ';' at the end */
decls: /* EMPTY */ { $$ = NULL; }
| one_decl ';' decls {
$$ = $1;
$$->aux = (int) $3;
}
;
/* Declarations that have no ';' at the end. */
declsn: one_decl { $$ = $1; }
| declsn ';' one_decl {
$$ = $1;
$$->aux = (int) $3;
}
;
filter_body:
function_body {
struct filter *f = cfg_alloc(sizeof(struct filter));
f->name = NULL;
f->root = $1;
$$ = f;
}
;
filter:
SYM {
if ($1->class != SYM_FILTER) cf_error("No such filter");
$$ = $1->def;
}
| filter_body
;
where_filter:
WHERE term {
/* Construct 'IF term THEN ACCEPT; REJECT;' */
struct filter *f = cfg_alloc(sizeof(struct filter));
struct f_inst *i, *acc, *rej;
acc = f_new_inst(); /* ACCEPT */
acc->code = P('p',',');
acc->a1.p = NULL;
acc->a2.i = F_ACCEPT;
rej = f_new_inst(); /* REJECT */
rej->code = P('p',',');
rej->a1.p = NULL;
rej->a2.i = F_REJECT;
i = f_new_inst(); /* IF */
i->code = '?';
i->a1.p = $2;
i->a2.p = acc;
i->next = rej;
f->name = NULL;
f->root = i;
$$ = f;
}
;
function_params:
'(' declsn ')' { DBG( "Have function parameters\n" ); $$=$2; }
| '(' ')' { $$=NULL; }
;
function_body:
decls '{' cmds '}' {
$$ = $3;
}
;
CF_ADDTO(conf, function_def)
function_def:
FUNCTION SYM { DBG( "Begining of function %s\n", $2->name ); cf_push_scope($2); } function_params function_body {
extern struct f_inst *startup_func;
cf_define_symbol($2, SYM_FUNCTION, $5);
if (!strcasecmp($2->name, "startup"))
startup_func = $5;
$2->aux = (int) $4;
$2->aux2 = $5;
DBG("Hmm, we've got one function here - %s\n", $2->name);
cf_pop_scope();
}
;
/* Programs */
cmds: /* EMPTY */ { $$ = NULL; }
| cmd cmds {
if ($1) {
if ($1->next)
bug("Command has next already set\n");
$1->next = $2;
$$ = $1;
} else $$ = $2;
}
;
block:
cmd {
$$=$1;
}
| '{' cmds '}' {
$$=$2;
}
;
/*
* Simple types, their bison value is int
*/
pair:
'(' NUM ',' NUM ')' { $$ = $2 << 16 | $4; }
;
/*
* Complex types, their bison value is struct f_val
*/
prefix_s:
IPA '/' NUM { $$.type = T_PREFIX; $$.val.px.ip = $1; $$.val.px.len = $3; if (ipa_nonzero(ipa_and($$.val.px.ip, ipa_not(ipa_mkmask($$.val.px.len))))) cf_error( "%I/%d is not really prefix\n", $$.val.px.ip, $$.val.px.len ); }
;
prefix:
prefix_s { $$ = $1; }
| prefix_s '+' { $$ = $1; $$.val.px.len |= LEN_PLUS; }
| prefix_s '-' { $$ = $1; $$.val.px.len |= LEN_MINUS; }
| prefix_s '{' NUM ',' NUM '}' { $$ = $1; $$.val.px.len |= LEN_RANGE | ($3 << 16) | ($5 << 8); }
;
ipa:
IPA { $$.type = T_IP; $$.val.px.ip = $1; }
;
set_atom:
NUM { $$.type = T_INT; $$.val.i = $1; }
| pair { $$.type = T_PAIR; $$.val.i = $1; }
| ipa { $$ = $1; }
| prefix { $$ = $1; }
;
set_item:
set_atom {
$$ = f_new_tree();
$$->from = $1;
if ($1.type != T_PREFIX)
$$->to = $1;
else {
$$->to = $1;
$$->to.val.px.ip = ipa_or( $$->to.val.px.ip, ipa_not( ipa_mkmask( $$->to.val.px.len ) ));
}
}
| set_atom '.' '.' set_atom {
$$ = f_new_tree();
$$->from = $1;
$$->to = $4;
if (($1.type == T_PREFIX) || ($4.type == T_PREFIX)) cf_error( "You can not use prefixes for range" );
}
;
set_items:
set_item { $$ = $1; }
| set_items ',' set_item { $$ = $3; $$->left = $1; }
;
switch_body: /* EMPTY */ { $$ = NULL; }
| set_item ':' cmds switch_body {
$$ = $1;
$$->data = $3;
$$->left = $4;
}
| ELSE ':' cmds {
$$ = f_new_tree();
$$->from.type = T_VOID;
$$->to.type = T_VOID;
$$->data = $3;
}
;
/* CONST '(' expr ')' { $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_INT; $$->a2.i = $3; } */
bgp_one:
NUM { $$ = $1; }
;
bgp_path:
bgp_one { $$ = cfg_alloc(sizeof(struct f_path_mask)); $$->next = NULL; $$->val = $1; }
| bgp_one bgp_path { $$ = cfg_alloc(sizeof(struct f_path_mask)); $$->next = $2; $$->val = $1; }
;
constant:
NUM { $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_INT; $$->a2.i = $1; }
| TRUE { $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_BOOL; $$->a2.i = 1; }
| FALSE { $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_BOOL; $$->a2.i = 0; }
| TEXT { $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_STRING; $$->a2.p = $1; }
| pair { $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_PAIR; $$->a2.i = $1; }
| ipa { NEW_F_VAL; $$ = f_new_inst(); $$->code = 'C'; $$->a1.p = val; *val = $1; }
| prefix_s {NEW_F_VAL; $$ = f_new_inst(); $$->code = 'C'; $$->a1.p = val; *val = $1; }
| '[' set_items ']' { DBG( "We've got a set here..." ); $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_SET; $$->a2.p = build_tree($2); DBG( "ook\n" ); }
| ENUM { $$ = f_new_inst(); $$->code = 'c'; $$->aux = $1 >> 16; $$->a2.i = $1 & 0xffff; }
| '/' bgp_path '/' { $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_PATH_MASK; $$->a2.p = $2; }
;
/*
* Maybe there are no dynamic attributes defined by protocols.
* For such cases, we force the dynamic_attr list to contain
* at least an invalid token, so it's syntantically correct.
*/
CF_ADDTO(dynamic_attr, INVALID_TOKEN { $$ = NULL; })
rtadot: /* EMPTY, we are not permitted RTA. prefix */
;
function_call:
SYM '(' var_list ')' {
struct symbol *sym;
struct f_inst *inst = $3;
if ($1->class != SYM_FUNCTION)
cf_error("You can not call something which is not function. Really.");
DBG("You are calling function %s\n", $1->name);
$$ = f_new_inst();
$$->code = P('c','a');
$$->a1.p = inst;
$$->a2.p = $1->aux2;
sym = (void *) $1->aux;
while (sym || inst) {
if (!sym || !inst)
cf_error("wrong number of arguments for function %s.", $1->name);
DBG( "You should pass parameter called %s\n", sym->name);
inst->a1.p = sym;
sym = (void *) sym->aux;
inst = inst->next;
}
}
;
term:
'(' term ')' { $$ = $2; }
| term '+' term { $$ = f_new_inst(); $$->code = '+'; $$->a1.p = $1; $$->a2.p = $3; }
| term '=' term { $$ = f_new_inst(); $$->code = P('=','='); $$->a1.p = $1; $$->a2.p = $3; }
| term NEQ term { $$ = f_new_inst(); $$->code = P('!','='); $$->a1.p = $1; $$->a2.p = $3; }
| term '<' term { $$ = f_new_inst(); $$->code = '<'; $$->a1.p = $1; $$->a2.p = $3; }
| term LEQ term { $$ = f_new_inst(); $$->code = P('<','='); $$->a1.p = $1; $$->a2.p = $3; }
| term '>' term { $$ = f_new_inst(); $$->code = '<'; $$->a1.p = $3; $$->a2.p = $1; }
| term GEQ term { $$ = f_new_inst(); $$->code = P('<','='); $$->a1.p = $3; $$->a2.p = $1; }
| term '~' term { $$ = f_new_inst(); $$->code = '~'; $$->a1.p = $1; $$->a2.p = $3; }
| '!' term { $$ = f_new_inst(); $$->code = '!'; $$->a1.p = $2; }
| DEFINED '(' term ')' { $$ = f_new_inst(); $$->code = P('d','e'); $$->a1.p = $3; }
| constant { $$ = $1; }
| SYM {
$$ = f_new_inst();
switch ($1->class) {
case SYM_VARIABLE | T_INT:
case SYM_VARIABLE | T_PAIR:
case SYM_VARIABLE | T_PREFIX:
case SYM_VARIABLE | T_IP:
case SYM_VARIABLE | T_PATH_MASK:
$$->code = 'C';
$$->a1.p = $1->aux2;
break;
default:
cf_error("Can not use this class of symbol (%s,%x) as variable.", $1->name, $1->class );
}
}
| rtadot FROM { $$ = f_new_inst(); $$->code = 'a'; $$->aux = T_IP; $$->a2.i = OFFSETOF(struct rta, from); }
| rtadot GW { $$ = f_new_inst(); $$->code = 'a'; $$->aux = T_IP; $$->a2.i = OFFSETOF(struct rta, gw); }
| rtadot NET { $$ = f_new_inst(); $$->code = 'a'; $$->aux = T_PREFIX; $$->a2.i = 0x12345678; }
| rtadot SOURCE { $$ = f_new_inst(); $$->code = 'a'; $$->aux = T_ENUM_RTS; $$->a2.i = OFFSETOF(struct rta, source); }
| rtadot dynamic_attr { $$ = $2; $$->code = P('e','a'); }
| term '.' IP { $$ = f_new_inst(); $$->code = P('c','p'); $$->a1.p = $1; $$->aux = T_IP; }
| term '.' LEN { $$ = f_new_inst(); $$->code = P('c','p'); $$->a1.p = $1; $$->aux = T_INT; }
| term '.' MASK '(' term ')' { $$ = f_new_inst(); $$->code = P('i','M'); $$->a1.p = $1; $$->a2.p = $5; }
/* Communities */
/* This causes one shift/reduce conflict
| rtadot dynamic_attr '.' ADD '(' term ')' { }
| rtadot dynamic_attr '.' DELETE '(' term ')' { }
| rtadot dynamic_attr '.' CONTAINS '(' term ')' { }
| rtadot dynamic_attr '.' RESET { }
*/
/* Paths */
| rtadot dynamic_attr '.' APPEND '(' term ')' { }
| rtadot dynamic_attr '.' LEN { $$->code = P('P','l'); }
/* function_call is inlined here */
| SYM '(' var_list ')' {
struct symbol *sym;
struct f_inst *inst = $3;
if ($1->class != SYM_FUNCTION)
cf_error("You can not call something which is not function. Really.");
DBG("You are calling function %s\n", $1->name);
$$ = f_new_inst();
$$->code = P('c','a');
$$->a1.p = inst;
$$->a2.p = $1->aux2;
sym = (void *) $1->aux;
while (sym || inst) {
if (!sym || !inst)
cf_error("wrong number of arguments for function %s.", $1->name);
DBG( "You should pass parameter called %s\n", sym->name);
inst->a1.p = sym;
sym = (void *) sym->aux;
inst = inst->next;
}
}
;
break_command:
QUITBIRD { $$ = F_QUITBIRD }
| ACCEPT { $$ = F_ACCEPT }
| REJECT { $$ = F_REJECT }
| ERROR { $$ = F_ERROR }
| PRINT { $$ = F_NOP }
| PRINTN { $$ = F_NONL }
;
print_one:
term { $$ = f_new_inst(); $$->code = 'p'; $$->a1.p = $1; $$->a2.p = NULL; }
;
print_list: /* EMPTY */ { $$ = NULL; }
| print_one { $$ = $1; }
| print_one ',' print_list {
if ($1) {
$1->next = $3;
$$ = $1;
} else $$ = $3;
}
;
var_listn: term {
$$ = f_new_inst();
$$->code = 's';
$$->a1.p = NULL;
$$->a2.p = $1;
$$->next = NULL;
}
| term ',' var_listn {
$$ = f_new_inst();
$$->code = 's';
$$->a1.p = NULL;
$$->a2.p = $1;
$$->next = $3;
}
;
var_list: /* EMPTY */ { $$ = NULL; }
| var_listn { $$ = $1; }
;
cmd:
IF term THEN block {
$$ = f_new_inst();
$$->code = '?';
$$->a1.p = $2;
$$->a2.p = $4;
}
| IF term THEN block ELSE block {
struct f_inst *i = f_new_inst();
i->code = '?';
i->a1.p = $2;
i->a2.p = $4;
$$ = f_new_inst();
$$->code = '?';
$$->a1.p = i;
$$->a2.p = $6;
}
| SYM '=' term ';' {
$$ = f_new_inst();
DBG( "Ook, we'll set value\n" );
if (($1->class & ~T_MASK) != SYM_VARIABLE)
cf_error( "You may only set variables, and this is %x.\n", $1->class );
$$->code = 's';
$$->a1.p = $1;
$$->a2.p = $3;
}
| RETURN term ';' {
$$ = f_new_inst();
DBG( "Ook, we'll return the value\n" );
$$->code = 'r';
$$->a1.p = $2;
}
| rtadot dynamic_attr '=' term ';' {
$$ = $2;
$$->code = P('e','S');
$$->a1.p = $4;
}
| UNSET '(' rtadot dynamic_attr ')' ';' {
$$ = $4;
$$->aux = EAF_TYPE_UNDEF | EAF_TEMP;
$$->code = P('e','S');
$$->a1.p = NULL;
}
| break_command print_list ';' { $$ = f_new_inst(); $$->code = P('p',','); $$->a1.p = $2; $$->a2.i = $1; }
| function_call ';' { $$ = $1; }
| CASE term '{' switch_body '}' {
$$ = f_new_inst();
$$->code = P('S','W');
$$->a1.p = $2;
$$->a2.p = build_tree( $4 );
}
;
CF_END
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