diff options
Diffstat (limited to 'net/netfilter/nft_hash.c')
-rw-r--r-- | net/netfilter/nft_hash.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c new file mode 100644 index 0000000000..92d47e4692 --- /dev/null +++ b/net/netfilter/nft_hash.c @@ -0,0 +1,286 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2016 Laura Garcia <nevola@gmail.com> + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables_core.h> +#include <linux/jhash.h> + +struct nft_jhash { + u8 sreg; + u8 dreg; + u8 len; + bool autogen_seed:1; + u32 modulus; + u32 seed; + u32 offset; +}; + +static void nft_jhash_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + struct nft_jhash *priv = nft_expr_priv(expr); + const void *data = ®s->data[priv->sreg]; + u32 h; + + h = reciprocal_scale(jhash(data, priv->len, priv->seed), + priv->modulus); + + regs->data[priv->dreg] = h + priv->offset; +} + +struct nft_symhash { + u8 dreg; + u32 modulus; + u32 offset; +}; + +static void nft_symhash_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + struct nft_symhash *priv = nft_expr_priv(expr); + struct sk_buff *skb = pkt->skb; + u32 h; + + h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus); + + regs->data[priv->dreg] = h + priv->offset; +} + +static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = { + [NFTA_HASH_SREG] = { .type = NLA_U32 }, + [NFTA_HASH_DREG] = { .type = NLA_U32 }, + [NFTA_HASH_LEN] = NLA_POLICY_MAX(NLA_BE32, 255), + [NFTA_HASH_MODULUS] = { .type = NLA_U32 }, + [NFTA_HASH_SEED] = { .type = NLA_U32 }, + [NFTA_HASH_OFFSET] = { .type = NLA_U32 }, + [NFTA_HASH_TYPE] = { .type = NLA_U32 }, +}; + +static int nft_jhash_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_jhash *priv = nft_expr_priv(expr); + u32 len; + int err; + + if (!tb[NFTA_HASH_SREG] || + !tb[NFTA_HASH_DREG] || + !tb[NFTA_HASH_LEN] || + !tb[NFTA_HASH_MODULUS]) + return -EINVAL; + + if (tb[NFTA_HASH_OFFSET]) + priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET])); + + err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len); + if (err < 0) + return err; + if (len == 0) + return -ERANGE; + + priv->len = len; + + err = nft_parse_register_load(tb[NFTA_HASH_SREG], &priv->sreg, len); + if (err < 0) + return err; + + priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS])); + if (priv->modulus < 1) + return -ERANGE; + + if (priv->offset + priv->modulus - 1 < priv->offset) + return -EOVERFLOW; + + if (tb[NFTA_HASH_SEED]) { + priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED])); + } else { + priv->autogen_seed = true; + get_random_bytes(&priv->seed, sizeof(priv->seed)); + } + + return nft_parse_register_store(ctx, tb[NFTA_HASH_DREG], &priv->dreg, + NULL, NFT_DATA_VALUE, sizeof(u32)); +} + +static int nft_symhash_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_symhash *priv = nft_expr_priv(expr); + + if (!tb[NFTA_HASH_DREG] || + !tb[NFTA_HASH_MODULUS]) + return -EINVAL; + + if (tb[NFTA_HASH_OFFSET]) + priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET])); + + priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS])); + if (priv->modulus < 1) + return -ERANGE; + + if (priv->offset + priv->modulus - 1 < priv->offset) + return -EOVERFLOW; + + return nft_parse_register_store(ctx, tb[NFTA_HASH_DREG], + &priv->dreg, NULL, NFT_DATA_VALUE, + sizeof(u32)); +} + +static int nft_jhash_dump(struct sk_buff *skb, + const struct nft_expr *expr, bool reset) +{ + const struct nft_jhash *priv = nft_expr_priv(expr); + + if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg)) + goto nla_put_failure; + if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg)) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len))) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus))) + goto nla_put_failure; + if (!priv->autogen_seed && + nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed))) + goto nla_put_failure; + if (priv->offset != 0) + if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset))) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS))) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +static bool nft_jhash_reduce(struct nft_regs_track *track, + const struct nft_expr *expr) +{ + const struct nft_jhash *priv = nft_expr_priv(expr); + + nft_reg_track_cancel(track, priv->dreg, sizeof(u32)); + + return false; +} + +static int nft_symhash_dump(struct sk_buff *skb, + const struct nft_expr *expr, bool reset) +{ + const struct nft_symhash *priv = nft_expr_priv(expr); + + if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg)) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus))) + goto nla_put_failure; + if (priv->offset != 0) + if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset))) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM))) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +static bool nft_symhash_reduce(struct nft_regs_track *track, + const struct nft_expr *expr) +{ + struct nft_symhash *priv = nft_expr_priv(expr); + struct nft_symhash *symhash; + + if (!nft_reg_track_cmp(track, expr, priv->dreg)) { + nft_reg_track_update(track, expr, priv->dreg, sizeof(u32)); + return false; + } + + symhash = nft_expr_priv(track->regs[priv->dreg].selector); + if (priv->offset != symhash->offset || + priv->modulus != symhash->modulus) { + nft_reg_track_update(track, expr, priv->dreg, sizeof(u32)); + return false; + } + + if (!track->regs[priv->dreg].bitwise) + return true; + + return false; +} + +static struct nft_expr_type nft_hash_type; +static const struct nft_expr_ops nft_jhash_ops = { + .type = &nft_hash_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)), + .eval = nft_jhash_eval, + .init = nft_jhash_init, + .dump = nft_jhash_dump, + .reduce = nft_jhash_reduce, +}; + +static const struct nft_expr_ops nft_symhash_ops = { + .type = &nft_hash_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)), + .eval = nft_symhash_eval, + .init = nft_symhash_init, + .dump = nft_symhash_dump, + .reduce = nft_symhash_reduce, +}; + +static const struct nft_expr_ops * +nft_hash_select_ops(const struct nft_ctx *ctx, + const struct nlattr * const tb[]) +{ + u32 type; + + if (!tb[NFTA_HASH_TYPE]) + return &nft_jhash_ops; + + type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE])); + switch (type) { + case NFT_HASH_SYM: + return &nft_symhash_ops; + case NFT_HASH_JENKINS: + return &nft_jhash_ops; + default: + break; + } + return ERR_PTR(-EOPNOTSUPP); +} + +static struct nft_expr_type nft_hash_type __read_mostly = { + .name = "hash", + .select_ops = nft_hash_select_ops, + .policy = nft_hash_policy, + .maxattr = NFTA_HASH_MAX, + .owner = THIS_MODULE, +}; + +static int __init nft_hash_module_init(void) +{ + return nft_register_expr(&nft_hash_type); +} + +static void __exit nft_hash_module_exit(void) +{ + nft_unregister_expr(&nft_hash_type); +} + +module_init(nft_hash_module_init); +module_exit(nft_hash_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>"); +MODULE_ALIAS_NFT_EXPR("hash"); +MODULE_DESCRIPTION("Netfilter nftables hash module"); 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