diff options
Diffstat (limited to 'net/netfilter/nft_payload.c')
| -rw-r--r-- | net/netfilter/nft_payload.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c new file mode 100644 index 00000000000..85daa84bfdf --- /dev/null +++ b/net/netfilter/nft_payload.c @@ -0,0 +1,161 @@ +/* + * 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> + +static void nft_payload_eval(const struct nft_expr *expr, + struct nft_data data[NFT_REG_MAX + 1], + const struct nft_pktinfo *pkt) +{ + const struct nft_payload *priv = nft_expr_priv(expr); + const struct sk_buff *skb = pkt->skb; + struct nft_data *dest = &data[priv->dreg]; + int offset; + + switch (priv->base) { + case NFT_PAYLOAD_LL_HEADER: + if (!skb_mac_header_was_set(skb)) + goto err; + offset = skb_mac_header(skb) - skb->data; + break; + case NFT_PAYLOAD_NETWORK_HEADER: + offset = skb_network_offset(skb); + break; + case NFT_PAYLOAD_TRANSPORT_HEADER: + offset = pkt->xt.thoff; + break; + default: + BUG(); + } + offset += priv->offset; + + if (skb_copy_bits(skb, offset, dest->data, priv->len) < 0) + goto err; + return; +err: + data[NFT_REG_VERDICT].verdict = NFT_BREAK; +} + +static const struct nla_policy nft_payload_policy[NFTA_PAYLOAD_MAX + 1] = { + [NFTA_PAYLOAD_DREG] = { .type = NLA_U32 }, + [NFTA_PAYLOAD_BASE] = { .type = NLA_U32 }, + [NFTA_PAYLOAD_OFFSET] = { .type = NLA_U32 }, + [NFTA_PAYLOAD_LEN] = { .type = NLA_U32 }, +}; + +static int nft_payload_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_payload *priv = nft_expr_priv(expr); + int err; + + priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE])); + priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET])); + priv->len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN])); + + priv->dreg = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_DREG])); + err = nft_validate_output_register(priv->dreg); + if (err < 0) + return err; + return nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE); +} + +static int nft_payload_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_payload *priv = nft_expr_priv(expr); + + if (nla_put_be32(skb, NFTA_PAYLOAD_DREG, htonl(priv->dreg)) || + nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) || + nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) || + nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len))) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +static struct nft_expr_type nft_payload_type; +static const struct nft_expr_ops nft_payload_ops = { + .type = &nft_payload_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_payload)), + .eval = nft_payload_eval, + .init = nft_payload_init, + .dump = nft_payload_dump, +}; + +const struct nft_expr_ops nft_payload_fast_ops = { + .type = &nft_payload_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_payload)), + .eval = nft_payload_eval, + .init = nft_payload_init, + .dump = nft_payload_dump, +}; + +static const struct nft_expr_ops * +nft_payload_select_ops(const struct nft_ctx *ctx, + const struct nlattr * const tb[]) +{ + enum nft_payload_bases base; + unsigned int offset, len; + + if (tb[NFTA_PAYLOAD_DREG] == NULL || + tb[NFTA_PAYLOAD_BASE] == NULL || + tb[NFTA_PAYLOAD_OFFSET] == NULL || + tb[NFTA_PAYLOAD_LEN] == NULL) + return ERR_PTR(-EINVAL); + + base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE])); + switch (base) { + case NFT_PAYLOAD_LL_HEADER: + case NFT_PAYLOAD_NETWORK_HEADER: + case NFT_PAYLOAD_TRANSPORT_HEADER: + break; + default: + return ERR_PTR(-EOPNOTSUPP); + } + + offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET])); + len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN])); + if (len == 0 || len > FIELD_SIZEOF(struct nft_data, data)) + return ERR_PTR(-EINVAL); + + if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) && + base != NFT_PAYLOAD_LL_HEADER) + return &nft_payload_fast_ops; + else + return &nft_payload_ops; +} + +static struct nft_expr_type nft_payload_type __read_mostly = { + .name = "payload", + .select_ops = nft_payload_select_ops, + .policy = nft_payload_policy, + .maxattr = NFTA_PAYLOAD_MAX, + .owner = THIS_MODULE, +}; + +int __init nft_payload_module_init(void) +{ + return nft_register_expr(&nft_payload_type); +} + +void nft_payload_module_exit(void) +{ + nft_unregister_expr(&nft_payload_type); +} |