From 795595f68d6c787028345804bb06f5a633af24a2 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 28 Nov 2016 00:05:52 +0100 Subject: [PATCH] netfilter: nft_quota: dump consumed quota Add a new attribute NFTA_QUOTA_CONSUMED that displays the amount of quota that has been already consumed. This allows us to restore the internal state of the quota object between reboots as well as to monitor how wasted it is. This patch changes the logic to account for the consumed bytes, instead of the bytes that remain to be consumed. Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/nf_tables.h | 2 ++ net/netfilter/nft_quota.c | 21 ++++++++++++++++----- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 1043ce4..3d47582c 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -988,12 +988,14 @@ enum nft_quota_flags { * * @NFTA_QUOTA_BYTES: quota in bytes (NLA_U16) * @NFTA_QUOTA_FLAGS: flags (NLA_U32) + * @NFTA_QUOTA_CONSUMED: quota already consumed in bytes (NLA_U64) */ enum nft_quota_attributes { NFTA_QUOTA_UNSPEC, NFTA_QUOTA_BYTES, NFTA_QUOTA_FLAGS, NFTA_QUOTA_PAD, + NFTA_QUOTA_CONSUMED, __NFTA_QUOTA_MAX }; #define NFTA_QUOTA_MAX (__NFTA_QUOTA_MAX - 1) diff --git a/net/netfilter/nft_quota.c b/net/netfilter/nft_quota.c index 09ce72b..0d34420 100644 --- a/net/netfilter/nft_quota.c +++ b/net/netfilter/nft_quota.c @@ -18,20 +18,20 @@ struct nft_quota { u64 quota; bool invert; - atomic64_t remain; + atomic64_t consumed; }; static inline bool nft_overquota(struct nft_quota *priv, - const struct nft_pktinfo *pkt) + const struct sk_buff *skb) { - return atomic64_sub_return(pkt->skb->len, &priv->remain) < 0; + return atomic64_add_return(skb->len, &priv->consumed) >= priv->quota; } static inline void nft_quota_do_eval(struct nft_quota *priv, struct nft_regs *regs, const struct nft_pktinfo *pkt) { - if (nft_overquota(priv, pkt) ^ priv->invert) + if (nft_overquota(priv, pkt->skb) ^ priv->invert) regs->verdict.code = NFT_BREAK; } @@ -70,7 +70,7 @@ static int nft_quota_do_init(const struct nlattr * const tb[], priv->quota = quota; priv->invert = (flags & NFT_QUOTA_F_INV) ? true : false; - atomic64_set(&priv->remain, quota); + atomic64_set(&priv->consumed, 0); return 0; } @@ -86,9 +86,20 @@ static int nft_quota_obj_init(const struct nlattr * const tb[], static int nft_quota_do_dump(struct sk_buff *skb, const struct nft_quota *priv) { u32 flags = priv->invert ? NFT_QUOTA_F_INV : 0; + u64 consumed; + + consumed = atomic64_read(&priv->consumed); + /* Since we inconditionally increment consumed quota for each packet + * that we see, don't go over the quota boundary in what we send to + * userspace. + */ + if (consumed > priv->quota) + consumed = priv->quota; if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(priv->quota), NFTA_QUOTA_PAD) || + nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed), + NFTA_QUOTA_PAD) || nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags))) goto nla_put_failure; return 0; -- 2.7.4