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