bird/filter/f-util.c
Ondrej Zajicek (work) a2527ee53d Filter: Improve handling of stack frames in filter bytecode
When f_line is done, we have to pop the stack frame. The old code just
removed nominal number of args/vars. Change it to use stored ventry value
modified by number of returned values. This allows to allocate variables
on a stack frame during execution of f_lines instead of just at start.

But we need to know the number of returned values for a f_line. It is 1
for term, 0 for cmd. Store that to f_line during linearization.
2022-06-27 21:13:32 +02:00

183 lines
3.9 KiB
C

/*
* Filters: utility functions
*
* Copyright 1998 Pavel Machek <pavel@ucw.cz>
* 2017 Jan Maria Matejka <mq@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "nest/bird.h"
#include "conf/conf.h"
#include "filter/filter.h"
#include "filter/f-inst.h"
#include "lib/idm.h"
#include "nest/protocol.h"
#include "nest/route.h"
#define P(a,b) ((a<<8) | b)
const char *
filter_name(const struct filter *filter)
{
if (!filter)
return "ACCEPT";
else if (filter == FILTER_REJECT)
return "REJECT";
else if (!filter->sym)
return "(unnamed)";
else
return filter->sym->name;
}
struct filter *f_new_where(struct f_inst *where)
{
struct f_inst *cond = f_new_inst(FI_CONDITION, where,
f_new_inst(FI_DIE, F_ACCEPT),
f_new_inst(FI_DIE, F_REJECT));
struct filter *f = cfg_allocz(sizeof(struct filter));
f->root = f_linearize(cond, 0);
return f;
}
#define CA_KEY(n) n->name, n->fda.type
#define CA_NEXT(n) n->next
#define CA_EQ(na,ta,nb,tb) (!strcmp(na,nb) && (ta == tb))
#define CA_FN(n,t) (mem_hash(n, strlen(n)) ^ (t*0xaae99453U))
#define CA_ORDER 8 /* Fixed */
struct ca_storage {
struct ca_storage *next;
struct f_dynamic_attr fda;
u32 uc;
char name[0];
};
HASH(struct ca_storage) ca_hash;
static struct idm ca_idm;
static struct ca_storage **ca_storage;
static uint ca_storage_max;
static void
ca_free(resource *r)
{
struct custom_attribute *ca = (void *) r;
struct ca_storage *cas = HASH_FIND(ca_hash, CA, ca->name, ca->fda->type);
ASSERT(cas);
ca->name = NULL;
ca->fda = NULL;
if (!--cas->uc) {
uint id = EA_CUSTOM_ID(cas->fda.ea_code);
idm_free(&ca_idm, id);
HASH_REMOVE(ca_hash, CA, cas);
ca_storage[id] = NULL;
mb_free(cas);
}
}
static void
ca_dump(resource *r)
{
struct custom_attribute *ca = (void *) r;
debug("name \"%s\" id 0x%04x ea_type 0x%02x f_type 0x%02x\n",
ca->name, ca->fda->ea_code, ca->fda->type, ca->fda->f_type);
}
static struct resclass ca_class = {
.name = "Custom attribute",
.size = sizeof(struct custom_attribute),
.free = ca_free,
.dump = ca_dump,
.lookup = NULL,
.memsize = NULL,
};
struct custom_attribute *
ca_lookup(pool *p, const char *name, int f_type)
{
int ea_type;
switch (f_type) {
case T_INT:
ea_type = EAF_TYPE_INT;
break;
case T_IP:
ea_type = EAF_TYPE_IP_ADDRESS;
break;
case T_QUAD:
ea_type = EAF_TYPE_ROUTER_ID;
break;
case T_PATH:
ea_type = EAF_TYPE_AS_PATH;
break;
case T_CLIST:
ea_type = EAF_TYPE_INT_SET;
break;
case T_ECLIST:
ea_type = EAF_TYPE_EC_SET;
break;
case T_LCLIST:
ea_type = EAF_TYPE_LC_SET;
break;
default:
cf_error("Custom route attribute of unsupported type");
}
static int inited = 0;
if (!inited) {
idm_init(&ca_idm, &root_pool, 8);
HASH_INIT(ca_hash, &root_pool, CA_ORDER);
ca_storage_max = 256;
ca_storage = mb_allocz(&root_pool, sizeof(struct ca_storage *) * ca_storage_max);
inited++;
}
struct ca_storage *cas = HASH_FIND(ca_hash, CA, name, ea_type);
if (cas) {
cas->uc++;
} else {
uint id = idm_alloc(&ca_idm);
if (id >= EA_CUSTOM_BIT)
cf_error("Too many custom attributes.");
if (id >= ca_storage_max) {
ca_storage_max *= 2;
ca_storage = mb_realloc(ca_storage, sizeof(struct ca_storage *) * ca_storage_max * 2);
}
cas = mb_allocz(&root_pool, sizeof(struct ca_storage) + strlen(name) + 1);
cas->fda = f_new_dynamic_attr(ea_type, f_type, EA_CUSTOM(id));
cas->uc = 1;
strcpy(cas->name, name);
ca_storage[id] = cas;
HASH_INSERT(ca_hash, CA, cas);
}
struct custom_attribute *ca = ralloc(p, &ca_class);
ca->fda = &(cas->fda);
ca->name = cas->name;
return ca;
}
const char *
ea_custom_name(uint ea)
{
uint id = EA_CUSTOM_ID(ea);
if (id >= ca_storage_max)
return NULL;
if (!ca_storage[id])
return NULL;
return ca_storage[id]->name;
}