| // 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_net(nft_net(pkt), 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"); |