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netfilter: nft_osf: track register operations 

Allow to recycle the previous output of the OS fingerprint expression
if flags and ttl are the same.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2022-03-14 18:23:06 +01:00
parent 4e2b29d881
commit ffe6488e62
1 changed files with 25 additions and 0 deletions
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25
net/netfilter/nft_osf.c
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@ -120,6 +120,30 @@ static int nft_osf_validate(const struct nft_ctx *ctx,
(1 << NF_INET_FORWARD));
}
static bool nft_osf_reduce(struct nft_regs_track *track,
const struct nft_expr *expr)
{
struct nft_osf *priv = nft_expr_priv(expr);
struct nft_osf *osf;
if (!nft_reg_track_cmp(track, expr, priv->dreg)) {
nft_reg_track_update(track, expr, priv->dreg, NFT_OSF_MAXGENRELEN);
return false;
}
osf = nft_expr_priv(track->regs[priv->dreg].selector);
if (priv->flags != osf->flags ||
priv->ttl != osf->ttl) {
nft_reg_track_update(track, expr, priv->dreg, NFT_OSF_MAXGENRELEN);
return false;
}
if (!track->regs[priv->dreg].bitwise)
return true;
return false;
}
static struct nft_expr_type nft_osf_type;
static const struct nft_expr_ops nft_osf_op = {
.eval = nft_osf_eval,
@ -128,6 +152,7 @@ static const struct nft_expr_ops nft_osf_op = {
.dump = nft_osf_dump,
.type = &nft_osf_type,
.validate = nft_osf_validate,
.reduce = nft_osf_reduce,
};
static struct nft_expr_type nft_osf_type __read_mostly = {