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