1 /* 2 * Copyright (c) 2008-2009 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_core.h> 18 #include <net/netfilter/nf_tables.h> 19 20 struct nft_bitwise { 21 enum nft_registers sreg:8; 22 enum nft_registers dreg:8; 23 u8 len; 24 struct nft_data mask; 25 struct nft_data xor; 26 }; 27 28 static void nft_bitwise_eval(const struct nft_expr *expr, 29 struct nft_regs *regs, 30 const struct nft_pktinfo *pkt) 31 { 32 const struct nft_bitwise *priv = nft_expr_priv(expr); 33 const u32 *src = ®s->data[priv->sreg]; 34 u32 *dst = ®s->data[priv->dreg]; 35 unsigned int i; 36 37 for (i = 0; i < DIV_ROUND_UP(priv->len, 4); i++) 38 dst[i] = (src[i] & priv->mask.data[i]) ^ priv->xor.data[i]; 39 } 40 41 static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = { 42 [NFTA_BITWISE_SREG] = { .type = NLA_U32 }, 43 [NFTA_BITWISE_DREG] = { .type = NLA_U32 }, 44 [NFTA_BITWISE_LEN] = { .type = NLA_U32 }, 45 [NFTA_BITWISE_MASK] = { .type = NLA_NESTED }, 46 [NFTA_BITWISE_XOR] = { .type = NLA_NESTED }, 47 }; 48 49 static int nft_bitwise_init(const struct nft_ctx *ctx, 50 const struct nft_expr *expr, 51 const struct nlattr * const tb[]) 52 { 53 struct nft_bitwise *priv = nft_expr_priv(expr); 54 struct nft_data_desc d1, d2; 55 int err; 56 57 if (tb[NFTA_BITWISE_SREG] == NULL || 58 tb[NFTA_BITWISE_DREG] == NULL || 59 tb[NFTA_BITWISE_LEN] == NULL || 60 tb[NFTA_BITWISE_MASK] == NULL || 61 tb[NFTA_BITWISE_XOR] == NULL) 62 return -EINVAL; 63 64 priv->len = ntohl(nla_get_be32(tb[NFTA_BITWISE_LEN])); 65 priv->sreg = nft_parse_register(tb[NFTA_BITWISE_SREG]); 66 err = nft_validate_register_load(priv->sreg, priv->len); 67 if (err < 0) 68 return err; 69 70 priv->dreg = nft_parse_register(tb[NFTA_BITWISE_DREG]); 71 err = nft_validate_register_store(ctx, priv->dreg, NULL, 72 NFT_DATA_VALUE, priv->len); 73 if (err < 0) 74 return err; 75 76 err = nft_data_init(NULL, &priv->mask, sizeof(priv->mask), &d1, 77 tb[NFTA_BITWISE_MASK]); 78 if (err < 0) 79 return err; 80 if (d1.len != priv->len) 81 return -EINVAL; 82 83 err = nft_data_init(NULL, &priv->xor, sizeof(priv->xor), &d2, 84 tb[NFTA_BITWISE_XOR]); 85 if (err < 0) 86 return err; 87 if (d2.len != priv->len) 88 return -EINVAL; 89 90 return 0; 91 } 92 93 static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr) 94 { 95 const struct nft_bitwise *priv = nft_expr_priv(expr); 96 97 if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg)) 98 goto nla_put_failure; 99 if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg)) 100 goto nla_put_failure; 101 if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len))) 102 goto nla_put_failure; 103 104 if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask, 105 NFT_DATA_VALUE, priv->len) < 0) 106 goto nla_put_failure; 107 108 if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor, 109 NFT_DATA_VALUE, priv->len) < 0) 110 goto nla_put_failure; 111 112 return 0; 113 114 nla_put_failure: 115 return -1; 116 } 117 118 static struct nft_expr_type nft_bitwise_type; 119 static const struct nft_expr_ops nft_bitwise_ops = { 120 .type = &nft_bitwise_type, 121 .size = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)), 122 .eval = nft_bitwise_eval, 123 .init = nft_bitwise_init, 124 .dump = nft_bitwise_dump, 125 }; 126 127 static struct nft_expr_type nft_bitwise_type __read_mostly = { 128 .name = "bitwise", 129 .ops = &nft_bitwise_ops, 130 .policy = nft_bitwise_policy, 131 .maxattr = NFTA_BITWISE_MAX, 132 .owner = THIS_MODULE, 133 }; 134 135 int __init nft_bitwise_module_init(void) 136 { 137 return nft_register_expr(&nft_bitwise_type); 138 } 139 140 void nft_bitwise_module_exit(void) 141 { 142 nft_unregister_expr(&nft_bitwise_type); 143 } 144