| /* |
| * Copyright (c) 2016 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 version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/atomic.h> |
| #include <linux/netlink.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter/nf_tables.h> |
| #include <net/netfilter/nf_tables.h> |
| |
| struct nft_quota { |
| u64 quota; |
| unsigned long flags; |
| atomic64_t consumed; |
| }; |
| |
| static inline bool nft_overquota(struct nft_quota *priv, |
| const struct sk_buff *skb) |
| { |
| return atomic64_add_return(skb->len, &priv->consumed) >= priv->quota; |
| } |
| |
| static inline bool nft_quota_invert(struct nft_quota *priv) |
| { |
| return priv->flags & NFT_QUOTA_F_INV; |
| } |
| |
| 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->skb) ^ nft_quota_invert(priv)) |
| regs->verdict.code = NFT_BREAK; |
| } |
| |
| static const struct nla_policy nft_quota_policy[NFTA_QUOTA_MAX + 1] = { |
| [NFTA_QUOTA_BYTES] = { .type = NLA_U64 }, |
| [NFTA_QUOTA_FLAGS] = { .type = NLA_U32 }, |
| [NFTA_QUOTA_CONSUMED] = { .type = NLA_U64 }, |
| }; |
| |
| #define NFT_QUOTA_DEPLETED_BIT 1 /* From NFT_QUOTA_F_DEPLETED. */ |
| |
| static void nft_quota_obj_eval(struct nft_object *obj, |
| struct nft_regs *regs, |
| const struct nft_pktinfo *pkt) |
| { |
| struct nft_quota *priv = nft_obj_data(obj); |
| bool overquota; |
| |
| overquota = nft_overquota(priv, pkt->skb); |
| if (overquota ^ nft_quota_invert(priv)) |
| regs->verdict.code = NFT_BREAK; |
| |
| if (overquota && |
| !test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags)) |
| nft_obj_notify(nft_net(pkt), obj->table, obj, 0, 0, |
| NFT_MSG_NEWOBJ, nft_pf(pkt), 0, GFP_ATOMIC); |
| } |
| |
| static int nft_quota_do_init(const struct nlattr * const tb[], |
| struct nft_quota *priv) |
| { |
| unsigned long flags = 0; |
| u64 quota, consumed = 0; |
| |
| if (!tb[NFTA_QUOTA_BYTES]) |
| return -EINVAL; |
| |
| quota = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_BYTES])); |
| if (quota > S64_MAX) |
| return -EOVERFLOW; |
| |
| if (tb[NFTA_QUOTA_CONSUMED]) { |
| consumed = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_CONSUMED])); |
| if (consumed > quota) |
| return -EINVAL; |
| } |
| |
| if (tb[NFTA_QUOTA_FLAGS]) { |
| flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS])); |
| if (flags & ~NFT_QUOTA_F_INV) |
| return -EINVAL; |
| if (flags & NFT_QUOTA_F_DEPLETED) |
| return -EOPNOTSUPP; |
| } |
| |
| priv->quota = quota; |
| priv->flags = flags; |
| atomic64_set(&priv->consumed, consumed); |
| |
| return 0; |
| } |
| |
| static int nft_quota_obj_init(const struct nlattr * const tb[], |
| struct nft_object *obj) |
| { |
| struct nft_quota *priv = nft_obj_data(obj); |
| |
| return nft_quota_do_init(tb, priv); |
| } |
| |
| static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv, |
| bool reset) |
| { |
| u64 consumed, consumed_cap; |
| u32 flags = priv->flags; |
| |
| /* 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. |
| */ |
| consumed = atomic64_read(&priv->consumed); |
| if (consumed >= priv->quota) { |
| consumed_cap = priv->quota; |
| flags |= NFT_QUOTA_F_DEPLETED; |
| } else { |
| consumed_cap = consumed; |
| } |
| |
| 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_cap), |
| NFTA_QUOTA_PAD) || |
| nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags))) |
| goto nla_put_failure; |
| |
| if (reset) { |
| atomic64_sub(consumed, &priv->consumed); |
| clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags); |
| } |
| return 0; |
| |
| nla_put_failure: |
| return -1; |
| } |
| |
| static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj, |
| bool reset) |
| { |
| struct nft_quota *priv = nft_obj_data(obj); |
| |
| return nft_quota_do_dump(skb, priv, reset); |
| } |
| |
| static struct nft_object_type nft_quota_obj __read_mostly = { |
| .type = NFT_OBJECT_QUOTA, |
| .size = sizeof(struct nft_quota), |
| .maxattr = NFTA_QUOTA_MAX, |
| .policy = nft_quota_policy, |
| .init = nft_quota_obj_init, |
| .eval = nft_quota_obj_eval, |
| .dump = nft_quota_obj_dump, |
| .owner = THIS_MODULE, |
| }; |
| |
| static void nft_quota_eval(const struct nft_expr *expr, |
| struct nft_regs *regs, |
| const struct nft_pktinfo *pkt) |
| { |
| struct nft_quota *priv = nft_expr_priv(expr); |
| |
| nft_quota_do_eval(priv, regs, pkt); |
| } |
| |
| static int nft_quota_init(const struct nft_ctx *ctx, |
| const struct nft_expr *expr, |
| const struct nlattr * const tb[]) |
| { |
| struct nft_quota *priv = nft_expr_priv(expr); |
| |
| return nft_quota_do_init(tb, priv); |
| } |
| |
| static int nft_quota_dump(struct sk_buff *skb, const struct nft_expr *expr) |
| { |
| struct nft_quota *priv = nft_expr_priv(expr); |
| |
| return nft_quota_do_dump(skb, priv, false); |
| } |
| |
| static struct nft_expr_type nft_quota_type; |
| static const struct nft_expr_ops nft_quota_ops = { |
| .type = &nft_quota_type, |
| .size = NFT_EXPR_SIZE(sizeof(struct nft_quota)), |
| .eval = nft_quota_eval, |
| .init = nft_quota_init, |
| .dump = nft_quota_dump, |
| }; |
| |
| static struct nft_expr_type nft_quota_type __read_mostly = { |
| .name = "quota", |
| .ops = &nft_quota_ops, |
| .policy = nft_quota_policy, |
| .maxattr = NFTA_QUOTA_MAX, |
| .flags = NFT_EXPR_STATEFUL, |
| .owner = THIS_MODULE, |
| }; |
| |
| static int __init nft_quota_module_init(void) |
| { |
| int err; |
| |
| err = nft_register_obj(&nft_quota_obj); |
| if (err < 0) |
| return err; |
| |
| err = nft_register_expr(&nft_quota_type); |
| if (err < 0) |
| goto err1; |
| |
| return 0; |
| err1: |
| nft_unregister_obj(&nft_quota_obj); |
| return err; |
| } |
| |
| static void __exit nft_quota_module_exit(void) |
| { |
| nft_unregister_expr(&nft_quota_type); |
| nft_unregister_obj(&nft_quota_obj); |
| } |
| |
| module_init(nft_quota_module_init); |
| module_exit(nft_quota_module_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); |
| MODULE_ALIAS_NFT_EXPR("quota"); |
| MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA); |