diff options
Diffstat (limited to 'net/netfilter/nft_cmp.c')
| -rw-r--r-- | net/netfilter/nft_cmp.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c new file mode 100644 index 000000000000..954925db414d --- /dev/null +++ b/net/netfilter/nft_cmp.c @@ -0,0 +1,223 @@ +/* + * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> + * + * 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. + * + * Development of this code funded by Astaro AG (http://www.astaro.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_core.h> +#include <net/netfilter/nf_tables.h> + +struct nft_cmp_expr { + struct nft_data data; + enum nft_registers sreg:8; + u8 len; + enum nft_cmp_ops op:8; +}; + +static void nft_cmp_eval(const struct nft_expr *expr, + struct nft_data data[NFT_REG_MAX + 1], + const struct nft_pktinfo *pkt) +{ + const struct nft_cmp_expr *priv = nft_expr_priv(expr); + int d; + + d = nft_data_cmp(&data[priv->sreg], &priv->data, priv->len); + switch (priv->op) { + case NFT_CMP_EQ: + if (d != 0) + goto mismatch; + break; + case NFT_CMP_NEQ: + if (d == 0) + goto mismatch; + break; + case NFT_CMP_LT: + if (d == 0) + goto mismatch; + case NFT_CMP_LTE: + if (d > 0) + goto mismatch; + break; + case NFT_CMP_GT: + if (d == 0) + goto mismatch; + case NFT_CMP_GTE: + if (d < 0) + goto mismatch; + break; + } + return; + +mismatch: + data[NFT_REG_VERDICT].verdict = NFT_BREAK; +} + +static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { + [NFTA_CMP_SREG] = { .type = NLA_U32 }, + [NFTA_CMP_OP] = { .type = NLA_U32 }, + [NFTA_CMP_DATA] = { .type = NLA_NESTED }, +}; + +static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_cmp_expr *priv = nft_expr_priv(expr); + struct nft_data_desc desc; + int err; + + priv->sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); + priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); + + err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]); + BUG_ON(err < 0); + + priv->len = desc.len; + return 0; +} + +static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_cmp_expr *priv = nft_expr_priv(expr); + + if (nla_put_be32(skb, NFTA_CMP_SREG, htonl(priv->sreg))) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) + goto nla_put_failure; + + if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, + NFT_DATA_VALUE, priv->len) < 0) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +static struct nft_expr_type nft_cmp_type; +static const struct nft_expr_ops nft_cmp_ops = { + .type = &nft_cmp_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), + .eval = nft_cmp_eval, + .init = nft_cmp_init, + .dump = nft_cmp_dump, +}; + +static int nft_cmp_fast_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); + struct nft_data_desc desc; + struct nft_data data; + u32 mask; + int err; + + priv->sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); + + err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); + BUG_ON(err < 0); + desc.len *= BITS_PER_BYTE; + + mask = ~0U >> (sizeof(priv->data) * BITS_PER_BYTE - desc.len); + priv->data = data.data[0] & mask; + priv->len = desc.len; + return 0; +} + +static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); + struct nft_data data; + + if (nla_put_be32(skb, NFTA_CMP_SREG, htonl(priv->sreg))) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) + goto nla_put_failure; + + data.data[0] = priv->data; + if (nft_data_dump(skb, NFTA_CMP_DATA, &data, + NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +const struct nft_expr_ops nft_cmp_fast_ops = { + .type = &nft_cmp_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), + .eval = NULL, /* inlined */ + .init = nft_cmp_fast_init, + .dump = nft_cmp_fast_dump, +}; + +static const struct nft_expr_ops * +nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) +{ + struct nft_data_desc desc; + struct nft_data data; + enum nft_registers sreg; + enum nft_cmp_ops op; + int err; + + if (tb[NFTA_CMP_SREG] == NULL || + tb[NFTA_CMP_OP] == NULL || + tb[NFTA_CMP_DATA] == NULL) + return ERR_PTR(-EINVAL); + + sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); + err = nft_validate_input_register(sreg); + if (err < 0) + return ERR_PTR(err); + + op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); + switch (op) { + case NFT_CMP_EQ: + case NFT_CMP_NEQ: + case NFT_CMP_LT: + case NFT_CMP_LTE: + case NFT_CMP_GT: + case NFT_CMP_GTE: + break; + default: + return ERR_PTR(-EINVAL); + } + + err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); + if (err < 0) + return ERR_PTR(err); + + if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) + return &nft_cmp_fast_ops; + else + return &nft_cmp_ops; +} + +static struct nft_expr_type nft_cmp_type __read_mostly = { + .name = "cmp", + .select_ops = nft_cmp_select_ops, + .policy = nft_cmp_policy, + .maxattr = NFTA_CMP_MAX, + .owner = THIS_MODULE, +}; + +int __init nft_cmp_module_init(void) +{ + return nft_register_expr(&nft_cmp_type); +} + +void nft_cmp_module_exit(void) +{ + nft_unregister_expr(&nft_cmp_type); +} |