bird/filter/config.Y

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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
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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
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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,
PREPEND, MATCH,
EMPTY,
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
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%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 {
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cf_define_symbol($2, SYM_FILTER, $4);
$4->name = $2->name;
DBG( "We have new filter defined (%s)\n", $2->name );
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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 '}' {
$$ = $3;
}
;
CF_ADDTO(conf, function_def)
function_def:
FUNCTION SYM { DBG( "Begining of function %s\n", $2->name ); cf_push_scope($2); } function_params function_body {
extern struct f_inst *startup_func;
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cf_define_symbol($2, SYM_FUNCTION, $5);
if (!strcasecmp($2->name, "startup"))
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startup_func = $5;
$2->aux = (int) $4;
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$2->aux2 = $5;
DBG("Hmm, we've got one function here - %s\n", $2->name);
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cf_pop_scope();
}
;
/* Programs */
cmds: /* EMPTY */ { $$ = 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; }
;
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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;
}
;
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/* CONST '(' expr ')' { $$ = f_new_inst(); $$->code = 'c'; $$->aux = T_INT; $$->a2.i = $3; } */
bgp_one:
NUM { $$ = $1; }
| '*' { $$ = PM_ANY; }
;
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:
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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'; $$->a1.p = val; *val = $1; }
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| prefix_s {NEW_F_VAL; $$ = 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 { $$ = NULL; })
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rtadot: /* EMPTY, we are not permitted RTA. prefix */
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;
function_call:
SYM '(' var_list ')' {
struct symbol *sym;
struct f_inst *inst = $3;
if ($1->class != SYM_FUNCTION)
cf_error("You can not call something which is not function. Really.");
DBG("You are calling function %s\n", $1->name);
$$ = 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; }
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| 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:
case SYM_VARIABLE | T_PATH:
case SYM_VARIABLE | T_CLIST:
$$->code = 'C';
$$->a1.p = $1->aux2;
break;
default:
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cf_error("Can not use this class of symbol (%s,%x) as variable.", $1->name, $1->class );
}
}
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| rtadot FROM { $$ = f_new_inst(); $$->code = 'a'; $$->aux = T_IP; $$->a2.i = OFFSETOF(struct rta, from); }
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| 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 = 'L'; $$->a1.p = $1; }
| term '.' MASK '(' term ')' { $$ = f_new_inst(); $$->code = P('i','M'); $$->a1.p = $1; $$->a2.p = $5; }
/* Communities */
/* This causes one shift/reduce conflict
| rtadot dynamic_attr '.' ADD '(' term ')' { }
| rtadot dynamic_attr '.' DELETE '(' term ')' { }
| rtadot dynamic_attr '.' CONTAINS '(' term ')' { }
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| rtadot dynamic_attr '.' RESET{ }
*/
/* Paths */
| term '.' PREPEND '(' term ')' { }
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| term '.' RESET { }
| '+' EMPTY '+' { $$ = f_new_inst(); $$->code = 'E'; $$->aux = T_PATH; }
| '-' EMPTY '-' { $$ = f_new_inst(); $$->code = 'E'; $$->aux = T_CLIST; }
| PREPEND '(' term ',' term ')' { $$ = f_new_inst(); $$->code = P('A','p'); $$->a1.p = $3; $$->a2.p = $5; }
| ADD '(' term ',' term ')' { $$ = f_new_inst(); $$->code = P('C','a'); $$->a1.p = $3; $$->a2.p = $5; $$->aux = 'a'; }
| DELETE '(' term ',' term ')' { $$ = f_new_inst(); $$->code = P('C','a'); $$->a1.p = $3; $$->a2.p = $5; $$->aux = 'd'; }
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/* | term '.' LEN { $$->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:
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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';
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$$->a1.p = $1;
$$->a2.p = $3;
}
| RETURN term ';' {
$$ = f_new_inst();
DBG( "Ook, we'll return the value\n" );
$$->code = 'r';
$$->a1.p = $2;
}
| rtadot dynamic_attr '=' term ';' {
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$$ = $2;
$$->code = P('e','S');
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$$->a1.p = $4;
}
| UNSET '(' rtadot dynamic_attr ')' ';' {
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$$ = $4;
$$->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;
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$$->a2.p = build_tree( $4 );
}
| rtadot dynamic_attr '.' EMPTY ';'
{ struct f_inst *i = f_new_inst(); i->code = 'E'; i->aux = T_CLIST; $$ = $2; $$->code = P('e','S'); $$->a1.p = i; }
| rtadot dynamic_attr '.' PREPEND '(' term ')' ';' { $$ = f_generate_complex( P('A','p'), 'x', $2, $6 ); }
| rtadot dynamic_attr '.' ADD '(' term ')' ';' { $$ = f_generate_complex( P('C','a'), 'a', $2, $6 ); }
| rtadot dynamic_attr '.' DELETE '(' term ')' ';' { $$ = f_generate_complex( P('C','a'), 'd', $2, $6 ); }
;
CF_END