diff options
Diffstat (limited to 'net/netfilter/nft_exthdr.c')
-rw-r--r-- | net/netfilter/nft_exthdr.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c new file mode 100644 index 0000000..8e0bb75 --- /dev/null +++ b/net/netfilter/nft_exthdr.c @@ -0,0 +1,133 @@ +/* + * Copyright (c) 2008 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.h> +// FIXME: +#include <net/ipv6.h> + +struct nft_exthdr { + u8 type; + u8 offset; + u8 len; + enum nft_registers dreg:8; +}; + +static void nft_exthdr_eval(const struct nft_expr *expr, + struct nft_data data[NFT_REG_MAX + 1], + const struct nft_pktinfo *pkt) +{ + struct nft_exthdr *priv = nft_expr_priv(expr); + struct nft_data *dest = &data[priv->dreg]; + unsigned int offset; + int err; + + err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL); + if (err < 0) + goto err; + offset += priv->offset; + + if (skb_copy_bits(pkt->skb, offset, dest->data, priv->len) < 0) + goto err; + return; +err: + data[NFT_REG_VERDICT].verdict = NFT_BREAK; +} + +static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = { + [NFTA_EXTHDR_DREG] = { .type = NLA_U32 }, + [NFTA_EXTHDR_TYPE] = { .type = NLA_U8 }, + [NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 }, + [NFTA_EXTHDR_LEN] = { .type = NLA_U32 }, +}; + +static int nft_exthdr_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_exthdr *priv = nft_expr_priv(expr); + int err; + + if (tb[NFTA_EXTHDR_DREG] == NULL || + tb[NFTA_EXTHDR_TYPE] == NULL || + tb[NFTA_EXTHDR_OFFSET] == NULL || + tb[NFTA_EXTHDR_LEN] == NULL) + return -EINVAL; + + priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]); + priv->offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET])); + priv->len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN])); + if (priv->len == 0 || + priv->len > FIELD_SIZEOF(struct nft_data, data)) + return -EINVAL; + + priv->dreg = ntohl(nla_get_be32(tb[NFTA_EXTHDR_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_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_exthdr *priv = nft_expr_priv(expr); + + if (nla_put_be32(skb, NFTA_EXTHDR_DREG, htonl(priv->dreg))) + goto nla_put_failure; + if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type)) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset))) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len))) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + +static struct nft_expr_type nft_exthdr_type; +static const struct nft_expr_ops nft_exthdr_ops = { + .type = &nft_exthdr_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), + .eval = nft_exthdr_eval, + .init = nft_exthdr_init, + .dump = nft_exthdr_dump, +}; + +static struct nft_expr_type nft_exthdr_type __read_mostly = { + .name = "exthdr", + .ops = &nft_exthdr_ops, + .policy = nft_exthdr_policy, + .maxattr = NFTA_EXTHDR_MAX, + .owner = THIS_MODULE, +}; + +static int __init nft_exthdr_module_init(void) +{ + return nft_register_expr(&nft_exthdr_type); +} + +static void __exit nft_exthdr_module_exit(void) +{ + nft_unregister_expr(&nft_exthdr_type); +} + +module_init(nft_exthdr_module_init); +module_exit(nft_exthdr_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); +MODULE_ALIAS_NFT_EXPR("exthdr"); |