1 /* 2 * Copyright (c) 2016 Pablo Neira Ayuso <[email protected]> 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 9 #include <linux/kernel.h> 10 #include <linux/init.h> 11 #include <linux/module.h> 12 #include <linux/netlink.h> 13 #include <linux/netfilter.h> 14 #include <linux/netfilter/nf_tables.h> 15 #include <net/netfilter/nf_tables_core.h> 16 #include <net/netfilter/nf_tables.h> 17 18 struct nft_range_expr { 19 struct nft_data data_from; 20 struct nft_data data_to; 21 enum nft_registers sreg:8; 22 u8 len; 23 enum nft_range_ops op:8; 24 }; 25 26 static void nft_range_eval(const struct nft_expr *expr, 27 struct nft_regs *regs, 28 const struct nft_pktinfo *pkt) 29 { 30 const struct nft_range_expr *priv = nft_expr_priv(expr); 31 bool mismatch; 32 int d1, d2; 33 34 d1 = memcmp(®s->data[priv->sreg], &priv->data_from, priv->len); 35 d2 = memcmp(®s->data[priv->sreg], &priv->data_to, priv->len); 36 switch (priv->op) { 37 case NFT_RANGE_EQ: 38 mismatch = (d1 < 0 || d2 > 0); 39 break; 40 case NFT_RANGE_NEQ: 41 mismatch = (d1 >= 0 && d2 <= 0); 42 break; 43 } 44 45 if (mismatch) 46 regs->verdict.code = NFT_BREAK; 47 } 48 49 static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = { 50 [NFTA_RANGE_SREG] = { .type = NLA_U32 }, 51 [NFTA_RANGE_OP] = { .type = NLA_U32 }, 52 [NFTA_RANGE_FROM_DATA] = { .type = NLA_NESTED }, 53 [NFTA_RANGE_TO_DATA] = { .type = NLA_NESTED }, 54 }; 55 56 static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 57 const struct nlattr * const tb[]) 58 { 59 struct nft_range_expr *priv = nft_expr_priv(expr); 60 struct nft_data_desc desc_from, desc_to; 61 int err; 62 u32 op; 63 64 err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from), 65 &desc_from, tb[NFTA_RANGE_FROM_DATA]); 66 if (err < 0) 67 return err; 68 69 err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to), 70 &desc_to, tb[NFTA_RANGE_TO_DATA]); 71 if (err < 0) 72 goto err1; 73 74 if (desc_from.len != desc_to.len) { 75 err = -EINVAL; 76 goto err2; 77 } 78 79 priv->sreg = nft_parse_register(tb[NFTA_RANGE_SREG]); 80 err = nft_validate_register_load(priv->sreg, desc_from.len); 81 if (err < 0) 82 goto err2; 83 84 err = nft_parse_u32_check(tb[NFTA_RANGE_OP], U8_MAX, &op); 85 if (err < 0) 86 goto err2; 87 88 switch (op) { 89 case NFT_RANGE_EQ: 90 case NFT_RANGE_NEQ: 91 break; 92 default: 93 err = -EINVAL; 94 goto err2; 95 } 96 97 priv->op = op; 98 priv->len = desc_from.len; 99 return 0; 100 err2: 101 nft_data_uninit(&priv->data_to, desc_to.type); 102 err1: 103 nft_data_uninit(&priv->data_from, desc_from.type); 104 return err; 105 } 106 107 static int nft_range_dump(struct sk_buff *skb, const struct nft_expr *expr) 108 { 109 const struct nft_range_expr *priv = nft_expr_priv(expr); 110 111 if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg)) 112 goto nla_put_failure; 113 if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op))) 114 goto nla_put_failure; 115 116 if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from, 117 NFT_DATA_VALUE, priv->len) < 0 || 118 nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to, 119 NFT_DATA_VALUE, priv->len) < 0) 120 goto nla_put_failure; 121 return 0; 122 123 nla_put_failure: 124 return -1; 125 } 126 127 static struct nft_expr_type nft_range_type; 128 static const struct nft_expr_ops nft_range_ops = { 129 .type = &nft_range_type, 130 .size = NFT_EXPR_SIZE(sizeof(struct nft_range_expr)), 131 .eval = nft_range_eval, 132 .init = nft_range_init, 133 .dump = nft_range_dump, 134 }; 135 136 static struct nft_expr_type nft_range_type __read_mostly = { 137 .name = "range", 138 .ops = &nft_range_ops, 139 .policy = nft_range_policy, 140 .maxattr = NFTA_RANGE_MAX, 141 .owner = THIS_MODULE, 142 }; 143 144 int __init nft_range_module_init(void) 145 { 146 return nft_register_expr(&nft_range_type); 147 } 148 149 void nft_range_module_exit(void) 150 { 151 nft_unregister_expr(&nft_range_type); 152 } 153