summaryrefslogtreecommitdiffstats
path: root/net/netfilter/nft_hash.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/netfilter/nft_hash.c')
-rw-r--r--net/netfilter/nft_hash.c286
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 000000000..92d47e469
--- /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 = &regs->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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-24 19:48:53 +0000