From b9ccc07e3f31ad8073697982bac014fbceef7ecb Mon Sep 17 00:00:00 2001 From: Laura Garcia Liebana Date: Fri, 11 May 2018 00:14:48 +0200 Subject: [PATCH] netfilter: nft_hash: add map lookups for hashing operations This patch creates new attributes to accept a map as argument and then perform the lookup with the generated hash accordingly. Both current hash functions are supported: Jenkins and Symmetric Hash. Signed-off-by: Laura Garcia Liebana Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/nf_tables.h | 4 + net/netfilter/nft_hash.c | 131 ++++++++++++++++++++++- 2 files changed, 134 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index ce031cf72288..9c71f024f9cc 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -856,6 +856,8 @@ enum nft_hash_types { * @NFTA_HASH_SEED: seed value (NLA_U32) * @NFTA_HASH_OFFSET: add this offset value to hash result (NLA_U32) * @NFTA_HASH_TYPE: hash operation (NLA_U32: nft_hash_types) + * @NFTA_HASH_SET_NAME: name of the map to lookup (NLA_STRING) + * @NFTA_HASH_SET_ID: id of the map (NLA_U32) */ enum nft_hash_attributes { NFTA_HASH_UNSPEC, @@ -866,6 +868,8 @@ enum nft_hash_attributes { NFTA_HASH_SEED, NFTA_HASH_OFFSET, NFTA_HASH_TYPE, + NFTA_HASH_SET_NAME, + NFTA_HASH_SET_ID, __NFTA_HASH_MAX, }; #define NFTA_HASH_MAX (__NFTA_HASH_MAX - 1) diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c index e235c17f1b8b..f0fc21f88775 100644 --- a/net/netfilter/nft_hash.c +++ b/net/netfilter/nft_hash.c @@ -25,6 +25,7 @@ struct nft_jhash { u32 modulus; u32 seed; u32 offset; + struct nft_set *map; }; static void nft_jhash_eval(const struct nft_expr *expr, @@ -35,14 +36,39 @@ static void nft_jhash_eval(const struct nft_expr *expr, const void *data = ®s->data[priv->sreg]; u32 h; - h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus); + h = reciprocal_scale(jhash(data, priv->len, priv->seed), + priv->modulus); + regs->data[priv->dreg] = h + priv->offset; } +static void nft_jhash_map_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]; + const struct nft_set *map = priv->map; + const struct nft_set_ext *ext; + u32 result; + bool found; + + result = reciprocal_scale(jhash(data, priv->len, priv->seed), + priv->modulus) + priv->offset; + + found = map->ops->lookup(nft_net(pkt), map, &result, &ext); + if (!found) + return; + + nft_data_copy(®s->data[priv->dreg], + nft_set_ext_data(ext), map->dlen); +} + struct nft_symhash { enum nft_registers dreg:8; u32 modulus; u32 offset; + struct nft_set *map; }; static void nft_symhash_eval(const struct nft_expr *expr, @@ -58,6 +84,28 @@ static void nft_symhash_eval(const struct nft_expr *expr, regs->data[priv->dreg] = h + priv->offset; } +static void nft_symhash_map_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; + const struct nft_set *map = priv->map; + const struct nft_set_ext *ext; + u32 result; + bool found; + + result = reciprocal_scale(__skb_get_hash_symmetric(skb), + priv->modulus) + priv->offset; + + found = map->ops->lookup(nft_net(pkt), map, &result, &ext); + if (!found) + return; + + nft_data_copy(®s->data[priv->dreg], + nft_set_ext_data(ext), map->dlen); +} + static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = { [NFTA_HASH_SREG] = { .type = NLA_U32 }, [NFTA_HASH_DREG] = { .type = NLA_U32 }, @@ -66,6 +114,9 @@ static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = { [NFTA_HASH_SEED] = { .type = NLA_U32 }, [NFTA_HASH_OFFSET] = { .type = NLA_U32 }, [NFTA_HASH_TYPE] = { .type = NLA_U32 }, + [NFTA_HASH_SET_NAME] = { .type = NLA_STRING, + .len = NFT_SET_MAXNAMELEN - 1 }, + [NFTA_HASH_SET_ID] = { .type = NLA_U32 }, }; static int nft_jhash_init(const struct nft_ctx *ctx, @@ -115,6 +166,23 @@ static int nft_jhash_init(const struct nft_ctx *ctx, NFT_DATA_VALUE, sizeof(u32)); } +static int nft_jhash_map_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_jhash *priv = nft_expr_priv(expr); + u8 genmask = nft_genmask_next(ctx->net); + + nft_jhash_init(ctx, expr, tb); + priv->map = nft_set_lookup_global(ctx->net, ctx->table, + tb[NFTA_HASH_SET_NAME], + tb[NFTA_HASH_SET_ID], genmask); + if (IS_ERR(priv->map)) + return PTR_ERR(priv->map); + + return 0; +} + static int nft_symhash_init(const struct nft_ctx *ctx, const struct nft_expr *expr, const struct nlattr * const tb[]) @@ -141,6 +209,23 @@ static int nft_symhash_init(const struct nft_ctx *ctx, NFT_DATA_VALUE, sizeof(u32)); } +static int nft_symhash_map_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_jhash *priv = nft_expr_priv(expr); + u8 genmask = nft_genmask_next(ctx->net); + + nft_symhash_init(ctx, expr, tb); + priv->map = nft_set_lookup_global(ctx->net, ctx->table, + tb[NFTA_HASH_SET_NAME], + tb[NFTA_HASH_SET_ID], genmask); + if (IS_ERR(priv->map)) + return PTR_ERR(priv->map); + + return 0; +} + static int nft_jhash_dump(struct sk_buff *skb, const struct nft_expr *expr) { @@ -168,6 +253,18 @@ static int nft_jhash_dump(struct sk_buff *skb, return -1; } +static int nft_jhash_map_dump(struct sk_buff *skb, + const struct nft_expr *expr) +{ + const struct nft_jhash *priv = nft_expr_priv(expr); + + if (nft_jhash_dump(skb, expr) || + nla_put_string(skb, NFTA_HASH_SET_NAME, priv->map->name)) + return -1; + + return 0; +} + static int nft_symhash_dump(struct sk_buff *skb, const struct nft_expr *expr) { @@ -188,6 +285,18 @@ static int nft_symhash_dump(struct sk_buff *skb, return -1; } +static int nft_symhash_map_dump(struct sk_buff *skb, + const struct nft_expr *expr) +{ + const struct nft_symhash *priv = nft_expr_priv(expr); + + if (nft_symhash_dump(skb, expr) || + nla_put_string(skb, NFTA_HASH_SET_NAME, priv->map->name)) + return -1; + + return 0; +} + static struct nft_expr_type nft_hash_type; static const struct nft_expr_ops nft_jhash_ops = { .type = &nft_hash_type, @@ -197,6 +306,14 @@ static const struct nft_expr_ops nft_jhash_ops = { .dump = nft_jhash_dump, }; +static const struct nft_expr_ops nft_jhash_map_ops = { + .type = &nft_hash_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)), + .eval = nft_jhash_map_eval, + .init = nft_jhash_map_init, + .dump = nft_jhash_map_dump, +}; + static const struct nft_expr_ops nft_symhash_ops = { .type = &nft_hash_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)), @@ -205,6 +322,14 @@ static const struct nft_expr_ops nft_symhash_ops = { .dump = nft_symhash_dump, }; +static const struct nft_expr_ops nft_symhash_map_ops = { + .type = &nft_hash_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)), + .eval = nft_symhash_map_eval, + .init = nft_symhash_map_init, + .dump = nft_symhash_map_dump, +}; + static const struct nft_expr_ops * nft_hash_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) @@ -217,8 +342,12 @@ nft_hash_select_ops(const struct nft_ctx *ctx, type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE])); switch (type) { case NFT_HASH_SYM: + if (tb[NFTA_HASH_SET_NAME]) + return &nft_symhash_map_ops; return &nft_symhash_ops; case NFT_HASH_JENKINS: + if (tb[NFTA_HASH_SET_NAME]) + return &nft_jhash_map_ops; return &nft_jhash_ops; default: break; -- 2.45.2