1 /* 2 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * Development of this code funded by Astaro AG (http://www.astaro.com/) 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/netlink.h> 15 #include <linux/netfilter.h> 16 #include <linux/netfilter/nf_tables.h> 17 #include <net/netfilter/nf_tables.h> 18 // FIXME: 19 #include <net/ipv6.h> 20 21 struct nft_exthdr { 22 u8 type; 23 u8 offset; 24 u8 len; 25 enum nft_registers dreg:8; 26 }; 27 28 static void nft_exthdr_eval(const struct nft_expr *expr, 29 struct nft_regs *regs, 30 const struct nft_pktinfo *pkt) 31 { 32 struct nft_exthdr *priv = nft_expr_priv(expr); 33 u32 *dest = ®s->data[priv->dreg]; 34 unsigned int offset = 0; 35 int err; 36 37 err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL); 38 if (err < 0) 39 goto err; 40 offset += priv->offset; 41 42 dest[priv->len / NFT_REG32_SIZE] = 0; 43 if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0) 44 goto err; 45 return; 46 err: 47 regs->verdict.code = NFT_BREAK; 48 } 49 50 static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = { 51 [NFTA_EXTHDR_DREG] = { .type = NLA_U32 }, 52 [NFTA_EXTHDR_TYPE] = { .type = NLA_U8 }, 53 [NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 }, 54 [NFTA_EXTHDR_LEN] = { .type = NLA_U32 }, 55 }; 56 57 static int nft_exthdr_init(const struct nft_ctx *ctx, 58 const struct nft_expr *expr, 59 const struct nlattr * const tb[]) 60 { 61 struct nft_exthdr *priv = nft_expr_priv(expr); 62 63 if (tb[NFTA_EXTHDR_DREG] == NULL || 64 tb[NFTA_EXTHDR_TYPE] == NULL || 65 tb[NFTA_EXTHDR_OFFSET] == NULL || 66 tb[NFTA_EXTHDR_LEN] == NULL) 67 return -EINVAL; 68 69 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]); 70 priv->offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET])); 71 priv->len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN])); 72 priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]); 73 74 return nft_validate_register_store(ctx, priv->dreg, NULL, 75 NFT_DATA_VALUE, priv->len); 76 } 77 78 static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr) 79 { 80 const struct nft_exthdr *priv = nft_expr_priv(expr); 81 82 if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg)) 83 goto nla_put_failure; 84 if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type)) 85 goto nla_put_failure; 86 if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset))) 87 goto nla_put_failure; 88 if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len))) 89 goto nla_put_failure; 90 return 0; 91 92 nla_put_failure: 93 return -1; 94 } 95 96 static struct nft_expr_type nft_exthdr_type; 97 static const struct nft_expr_ops nft_exthdr_ops = { 98 .type = &nft_exthdr_type, 99 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), 100 .eval = nft_exthdr_eval, 101 .init = nft_exthdr_init, 102 .dump = nft_exthdr_dump, 103 }; 104 105 static struct nft_expr_type nft_exthdr_type __read_mostly = { 106 .name = "exthdr", 107 .ops = &nft_exthdr_ops, 108 .policy = nft_exthdr_policy, 109 .maxattr = NFTA_EXTHDR_MAX, 110 .owner = THIS_MODULE, 111 }; 112 113 static int __init nft_exthdr_module_init(void) 114 { 115 return nft_register_expr(&nft_exthdr_type); 116 } 117 118 static void __exit nft_exthdr_module_exit(void) 119 { 120 nft_unregister_expr(&nft_exthdr_type); 121 } 122 123 module_init(nft_exthdr_module_init); 124 module_exit(nft_exthdr_module_exit); 125 126 MODULE_LICENSE("GPL"); 127 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 128 MODULE_ALIAS_NFT_EXPR("exthdr"); 129