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bird/filter/filter.c

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/*
* Filters: utility functions
*
* Copyright 1998 Pavel Machek <pavel@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*
* FIXME: local namespace for functions
*
* Notice that pair is stored as integer: first << 16 | second
*/
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/signal.h>
#include <setjmp.h>
#include "nest/bird.h"
#include "lib/lists.h"
#include "lib/resource.h"
#include "lib/socket.h"
#include "lib/string.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "conf/conf.h"
#include "filter/filter.h"
struct f_inst *startup_func = NULL;
#define runtime(x) do { \
log( L_ERR x ); \
res.type = T_RETURN; \
res.val.i = F_ERROR; \
return res; \
} while(0)
#define ARG(x,y) \
x = interpret(what->y); \
if (x.type == T_RETURN) \
return x;
#define ONEARG ARG(v1, a1.p)
#define TWOARGS ARG(v1, a1.p) \
ARG(v2, a2.p)
#define TWOARGS_C TWOARGS \
if (v1.type != v2.type) \
runtime( "Can not operate with values of incompatible types" );
#define CMP_ERROR 999
/* Compare two values, returns -1, 0, 1 compared, ERROR 999 */
int
val_compare(struct f_val v1, struct f_val v2)
{
if (v1.type != v2.type)
return CMP_ERROR;
switch (v1.type) {
case T_INT:
if (v1.val.i == v2.val.i) return 0;
if (v1.val.i < v2.val.i) return -1;
return 1;
case T_IP:
return ipa_compare(v1.val.ip, v2.val.ip);
default: return CMP_ERROR;
}
}
int
val_in_range(struct f_val v1, struct f_val v2)
{
if (((v1.type == T_INT) || (v1.type == T_IP)) && (v2.type == T_SET))
return !! find_tree(v2.val.t, v1);
return CMP_ERROR;
}
static void
tree_print(struct f_tree *t)
{
if (!t) {
printf( "() " );
return;
}
printf( "[ " );
tree_print( t->left );
printf( ", " ); val_print( t->from ); printf( ".." ); val_print( t->to ); printf( ", " );
tree_print( t->right );
printf( "] " );
}
void
val_print(struct f_val v)
{
char buf[2048];
#define PRINTF(a...) bsnprintf( buf, 2040, a )
buf[0] = 0;
switch (v.type) {
case T_VOID: PRINTF( "(void)" ); break;
case T_BOOL: PRINTF( v.val.i ? "TRUE" : "FALSE" ); break;
case T_INT: PRINTF( "%d ", v.val.i ); break;
case T_STRING: PRINTF( "%s", v.val.s ); break;
case T_IP: PRINTF( "%I", v.val.ip ); break;
case T_PREFIX: PRINTF( "%I/%d", v.val.px.ip, v.val.px.len ); break;
case T_PAIR: PRINTF( "(%d,%d)", v.val.i >> 16, v.val.i & 0xffff ); break;
case T_SET: tree_print( v.val.t ); PRINTF( "\n" ); break;
default: PRINTF( "[unknown type %x]", v.type );
}
printf( buf );
}
static struct rte **f_rte;
static struct f_val interpret(struct f_inst *what);
static struct f_val
interpret_switch(struct f_inst *what, struct f_val control)
{
struct f_val this, res;
int i;
res.type = T_VOID;
if (!what)
return res;
switch(what->code) {
case 'el':
return interpret(what->a2.p);
case 'of':
this = interpret(what->a1.p);
i = val_compare(control, this);
if (!i)
return interpret(what->a2.p);
if (i==CMP_ERROR) {
i = val_in_range(control, this);
if (i==1)
return interpret(what->a2.p);
if (i==CMP_ERROR)
runtime( "incompatible types in case" );
}
break;
default:
bug( "This can not happen (%x)\n", what->code );
}
return interpret_switch(what->next, control);
}
static struct f_val
interpret(struct f_inst *what)
{
struct symbol *sym;
struct f_val v1, v2, res;
int i,j,k;
res.type = T_VOID;
if (!what)
return res;
switch(what->code) {
case ',':
TWOARGS;
break;
/* Binary operators */
case '+':
TWOARGS_C;
switch (res.type = v1.type) {
case T_VOID: runtime( "Can not operate with values of type void" );
case T_INT: res.val.i = v1.val.i + v2.val.i; break;
default: runtime( "Usage of unknown type" );
}
break;
case '/':
TWOARGS_C;
switch (res.type = v1.type) {
case T_VOID: runtime( "Can not operate with values of type void" );
case T_INT: res.val.i = v1.val.i / v2.val.i; break;
case T_IP: if (v2.type != T_INT)
runtime( "Operator / is <ip>/<int>" );
break;
default: runtime( "Usage of unknown type" );
}
break;
/* Relational operators */
#define COMPARE(x) \
TWOARGS_C; \
res.type = T_BOOL; \
i = val_compare(v1, v2); \
if (i==CMP_ERROR) \
runtime( "Error in comparation" ); \
res.val.i = (x); \
break;
case '!=': COMPARE(i!=0);
case '==': COMPARE(i==0);
case '<': COMPARE(i==-1);
case '<=': COMPARE(i!=1);
/* FIXME: Should be able to work with prefixes of limited sizes */
case '~':
TWOARGS;
res.type = T_BOOL;
res.val.i = val_in_range(v1, v2);
if (res.val.i == CMP_ERROR)
runtime( "~ applied on unknown type pair" );
break;
/* Set to consant, a1 = type, a2 = value */
case 's':
ARG(v2, a2.p);
sym = what->a1.p;
switch (res.type = v2.type) {
case T_VOID: runtime( "Can not assign void values" );
case T_INT:
if (sym->class != (SYM_VARIABLE | T_INT))
runtime( "Variable of bad type" );
sym->aux = v2.val.i;
break;
}
break;
case 'c':
res.type = what->a1.i;
res.val.i = (int) what->a2.p;
break;
case 'C':
res = * ((struct f_val *) what->a1.p);
break;
case 'i':
res.type = what->a1.i;
res.val.i = * ((int *) what->a2.p);
break;
case 'p':
ONEARG;
val_print(v1);
break;
case '?': /* ? has really strange error value, so we can implement if ... else nicely :-) */
ONEARG;
if (v1.type != T_BOOL)
runtime( "If requires bool expression" );
if (v1.val.i) {
ARG(res,a2.p);
res.val.i = 0;
} else res.val.i = 1;
res.type = T_BOOL;
break;
case '0':
printf( "No operation\n" );
break;
case 'p,':
ONEARG;
printf( "\n" );
switch (what->a2.i) {
case F_QUITBIRD:
die( "Filter asked me to die" );
case F_ACCEPT:
/* Should take care about turning ACCEPT into MODIFY */
case F_ERROR:
case F_REJECT:
res.type = T_RETURN;
res.val.i = what->a1.i;
break;
case F_NOP:
break;
default:
bug( "unknown return type: can not happen");
}
break;
case 'a': /* rta access */
{
struct rta *rta = (*f_rte)->attrs;
res.type = what->a1.i;
switch(res.type) {
case T_IP:
res.val.ip = * (ip_addr *) ((char *) rta + what->a2.i);
break;
case T_PREFIX: /* Warning: this works only for prefix of network */
{
res.val.px.ip = (*f_rte)->net->n.prefix;
res.val.px.len = (*f_rte)->net->n.pxlen;
break;
}
default:
bug( "Invalid type for rta access" );
}
}
break;
case 'cp': /* Convert prefix to ... */
ONEARG;
if (v1.type != T_PREFIX)
runtime( "Can not convert non-prefix this way" );
res.type = what->a2.i;
switch(res.type) {
case T_INT: res.val.i = v1.val.px.len; break;
case T_IP: res.val.ip = v1.val.px.ip; break;
default: bug( "Unknown prefix to conversion\n" );
}
break;
case 'ca': /* CALL */
ONEARG;
res = interpret(what->a2.p);
break;
case 'sw': /* SWITCH alias CASE */
ONEARG;
interpret_switch(what->a2.p, v1);
break;
default:
bug( "Unknown instruction %d (%c)", what->code, what->code & 0xff);
}
if (what->next)
return interpret(what->next);
return res;
}
int
f_run(struct filter *filter, struct rte **rte, struct ea_list **tmp_attrs, struct linpool *tmp_pool)
{
struct f_inst *inst;
struct f_val res;
debug( "Running filter `%s'...", filter->name );
f_rte = rte;
inst = filter->root;
res = interpret(inst);
if (res.type != T_RETURN)
return F_ERROR;
debug( "done (%d)\n", res.val.i );
return res.val.i;
}
void
filters_postconfig(void)
{
struct f_val res;
if (startup_func) {
printf( "Launching startup function...\n" );
res = interpret(startup_func);
if (res.type == F_ERROR)
die( "Startup function resulted in error." );
printf( "done\n" );
}
}
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