136 lines
3.5 KiB
C
136 lines
3.5 KiB
C
/*
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* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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// FIXME:
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#include <net/ipv6.h>
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struct nft_exthdr {
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u8 type;
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u8 offset;
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u8 len;
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enum nft_registers dreg:8;
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};
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static void nft_exthdr_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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struct nft_exthdr *priv = nft_expr_priv(expr);
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u32 *dest = ®s->data[priv->dreg];
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unsigned int offset = 0;
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int err;
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err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
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if (err < 0)
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goto err;
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offset += priv->offset;
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dest[priv->len / NFT_REG32_SIZE] = 0;
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if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
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goto err;
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return;
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err:
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regs->verdict.code = NFT_BREAK;
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}
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static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
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[NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
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[NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
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[NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
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[NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
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};
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static int nft_exthdr_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_exthdr *priv = nft_expr_priv(expr);
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u32 offset, len;
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if (tb[NFTA_EXTHDR_DREG] == NULL ||
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tb[NFTA_EXTHDR_TYPE] == NULL ||
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tb[NFTA_EXTHDR_OFFSET] == NULL ||
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tb[NFTA_EXTHDR_LEN] == NULL)
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return -EINVAL;
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offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
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len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
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if (offset > U8_MAX || len > U8_MAX)
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return -ERANGE;
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priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
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priv->offset = offset;
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priv->len = len;
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priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
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return nft_validate_register_store(ctx, priv->dreg, NULL,
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NFT_DATA_VALUE, priv->len);
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}
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static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_exthdr *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
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goto nla_put_failure;
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if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static struct nft_expr_type nft_exthdr_type;
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static const struct nft_expr_ops nft_exthdr_ops = {
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.type = &nft_exthdr_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
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.eval = nft_exthdr_eval,
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.init = nft_exthdr_init,
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.dump = nft_exthdr_dump,
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};
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static struct nft_expr_type nft_exthdr_type __read_mostly = {
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.name = "exthdr",
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.ops = &nft_exthdr_ops,
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.policy = nft_exthdr_policy,
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.maxattr = NFTA_EXTHDR_MAX,
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.owner = THIS_MODULE,
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};
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static int __init nft_exthdr_module_init(void)
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{
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return nft_register_expr(&nft_exthdr_type);
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}
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static void __exit nft_exthdr_module_exit(void)
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{
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nft_unregister_expr(&nft_exthdr_type);
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}
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module_init(nft_exthdr_module_init);
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module_exit(nft_exthdr_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_ALIAS_NFT_EXPR("exthdr");
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