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/*
* (C) 2012-2022 by Pablo Neira Ayuso <pablo@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
/* Funded through the NGI0 PET Fund established by NLnet (https://nlnet.nl)
* with support from the European Commission's Next Generation Internet
* programme.
*/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <errno.h>
#include <assert.h>
#include <libnftnl/regs.h>
#include "internal.h"
EXPORT_SYMBOL(nftnl_regs_alloc);
struct nftnl_regs *nftnl_regs_alloc(uint32_t num_regs)
{
struct nftnl_regs *regs;
if (num_regs < 16)
num_regs = 16;
regs = calloc(1, sizeof(struct nftnl_regs));
if (!regs)
return NULL;
regs->reg = calloc(num_regs, sizeof(struct nftnl_reg));
if (!regs->reg) {
free(regs->reg);
return NULL;
}
regs->num_regs = num_regs;
return regs;
}
EXPORT_SYMBOL(nftnl_regs_free);
void nftnl_regs_free(const struct nftnl_regs *regs)
{
xfree(regs->reg);
xfree(regs);
}
static enum nftnl_expr_type nftnl_expr_type(const struct nftnl_expr *expr)
{
if (!strcmp(expr->ops->name, "meta"))
return NFT_EXPR_META;
else if (!strcmp(expr->ops->name, "payload"))
return NFT_EXPR_PAYLOAD;
assert(0);
return NFT_EXPR_UNSPEC;
}
static int nftnl_expr_reg_len(const struct nftnl_expr *expr)
{
return expr->ops->reg.len(expr);
}
static bool nftnl_expr_reg_cmp(const struct nftnl_regs *regs,
const struct nftnl_expr *expr, int i)
{
if (regs->reg[i].type != nftnl_expr_type(expr))
return false;
return expr->ops->reg.cmp(®s->reg[i], expr);
}
static void nft_expr_reg_update(struct nftnl_regs *regs,
const struct nftnl_expr *expr, int i)
{
return expr->ops->reg.update(®s->reg[i], expr);
}
static int reg_space(const struct nftnl_regs *regs, int i)
{
return sizeof(uint32_t) * regs->num_regs - sizeof(uint32_t) * i;
}
struct nftnl_reg_ctx {
uint64_t genid;
int reg;
int evict;
};
static void register_track(struct nftnl_reg_ctx *ctx,
const struct nftnl_regs *regs, int i, int len)
{
if (ctx->reg >= 0 || regs->reg[i].word || reg_space(regs, i) < len)
return;
if (regs->reg[i].type == NFT_EXPR_UNSPEC) {
ctx->genid = regs->genid;
ctx->reg = i;
} else if (regs->reg[i].genid < ctx->genid) {
ctx->genid = regs->reg[i].genid;
ctx->evict = i;
}
}
static void register_evict(struct nftnl_reg_ctx *ctx)
{
if (ctx->reg < 0) {
assert(ctx->evict >= 0);
ctx->reg = ctx->evict;
}
}
static void __register_update(struct nftnl_regs *regs, uint8_t reg,
int type, uint32_t len, uint8_t word,
uint64_t genid, const struct nftnl_expr *expr)
{
regs->reg[reg].type = type;
regs->reg[reg].genid = genid;
regs->reg[reg].len = len;
regs->reg[reg].word = word;
nft_expr_reg_update(regs, expr, reg);
}
static void __register_cancel(struct nftnl_regs *regs, int i)
{
regs->reg[i].type = NFT_EXPR_UNSPEC;
regs->reg[i].word = 0;
regs->reg[i].len = 0;
regs->reg[i].genid = 0;
}
static void register_cancel(struct nftnl_reg_ctx *ctx, struct nftnl_regs *regs,
int len)
{
int i;
for (i = ctx->reg; len > 0; i++, len -= sizeof(uint32_t)) {
if (regs->reg[i].type == NFT_EXPR_UNSPEC)
continue;
__register_cancel(regs, i);
}
while (i < regs->num_regs && regs->reg[i].word != 0) {
__register_cancel(regs, i);
i++;
}
}
static void register_update(struct nftnl_reg_ctx *ctx, struct nftnl_regs *regs,
int type, uint32_t len, uint64_t genid,
const struct nftnl_expr *expr)
{
register_cancel(ctx, regs, len);
__register_update(regs, ctx->reg, type, len, 0, genid, expr);
}
static uint64_t reg_genid(struct nftnl_regs *regs)
{
return ++regs->genid;
}
EXPORT_SYMBOL(nftnl_reg_get);
uint32_t nftnl_reg_get(struct nftnl_regs *regs, const struct nftnl_expr *expr)
{
struct nftnl_reg_ctx ctx = {
.reg = -1,
.evict = -1,
.genid = UINT64_MAX,
};
enum nftnl_expr_type type;
uint64_t genid;
int i, j, len;
type = nftnl_expr_type(expr);
len = nftnl_expr_reg_len(expr);
for (i = 0; i < regs->num_regs; i++) {
register_track(&ctx, regs, i, len);
if (!nftnl_expr_reg_cmp(regs, expr, i))
continue;
regs->reg[i].genid = reg_genid(regs);
return i + NFT_REG32_00;
}
register_evict(&ctx);
genid = reg_genid(regs);
register_update(&ctx, regs, type, len, genid, expr);
len -= sizeof(uint32_t);
j = 1;
for (i = ctx.reg + 1; len > 0; i++, len -= sizeof(uint32_t))
__register_update(regs, i, type, len, j++, genid, expr);
return ctx.reg + NFT_REG32_00;
}
EXPORT_SYMBOL(nftnl_reg_get_scratch);
uint32_t nftnl_reg_get_scratch(struct nftnl_regs *regs, uint32_t len)
{
struct nftnl_reg_ctx ctx = {
.reg = -1,
.evict = -1,
.genid = UINT64_MAX,
};
int i;
for (i = 0; i < regs->num_regs; i++)
register_track(&ctx, regs, i, len);
register_evict(&ctx);
register_cancel(&ctx, regs, len);
return ctx.reg + NFT_REG32_00;
}
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