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net/netfilter/nft_hash.c
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81f7e3824 Initial Release, ... |
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/* * Copyright (c) 2016 Laura Garcia <nevola@gmail.com> * * 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/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 { enum nft_registers sreg:8; enum nft_registers dreg:8; 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 { enum nft_registers dreg:8; 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] = { .type = NLA_U32 }, [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])); priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]); priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]); 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; 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_validate_register_load(priv->sreg, len) && nft_validate_register_store(ctx, 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->dreg = nft_parse_register(tb[NFTA_HASH_DREG]); 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_validate_register_store(ctx, priv->dreg, NULL, NFT_DATA_VALUE, sizeof(u32)); } static int nft_jhash_dump(struct sk_buff *skb, const struct nft_expr *expr) { 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 int nft_symhash_dump(struct sk_buff *skb, const struct nft_expr *expr) { 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 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, }; 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, }; 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"); |