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