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 63 err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from), 64 &desc_from, tb[NFTA_RANGE_FROM_DATA]); 65 if (err < 0) 66 return err; 67 68 err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to), 69 &desc_to, tb[NFTA_RANGE_TO_DATA]); 70 if (err < 0) 71 goto err1; 72 73 if (desc_from.len != desc_to.len) { 74 err = -EINVAL; 75 goto err2; 76 } 77 78 priv->sreg = nft_parse_register(tb[NFTA_RANGE_SREG]); 79 err = nft_validate_register_load(priv->sreg, desc_from.len); 80 if (err < 0) 81 goto err2; 82 83 priv->op = ntohl(nla_get_be32(tb[NFTA_RANGE_OP])); 84 priv->len = desc_from.len; 85 return 0; 86 err2: 87 nft_data_uninit(&priv->data_to, desc_to.type); 88 err1: 89 nft_data_uninit(&priv->data_from, desc_from.type); 90 return err; 91 } 92 93 static int nft_range_dump(struct sk_buff *skb, const struct nft_expr *expr) 94 { 95 const struct nft_range_expr *priv = nft_expr_priv(expr); 96 97 if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg)) 98 goto nla_put_failure; 99 if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op))) 100 goto nla_put_failure; 101 102 if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from, 103 NFT_DATA_VALUE, priv->len) < 0 || 104 nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to, 105 NFT_DATA_VALUE, priv->len) < 0) 106 goto nla_put_failure; 107 return 0; 108 109 nla_put_failure: 110 return -1; 111 } 112 113 static struct nft_expr_type nft_range_type; 114 static const struct nft_expr_ops nft_range_ops = { 115 .type = &nft_range_type, 116 .size = NFT_EXPR_SIZE(sizeof(struct nft_range_expr)), 117 .eval = nft_range_eval, 118 .init = nft_range_init, 119 .dump = nft_range_dump, 120 }; 121 122 static struct nft_expr_type nft_range_type __read_mostly = { 123 .name = "range", 124 .ops = &nft_range_ops, 125 .policy = nft_range_policy, 126 .maxattr = NFTA_RANGE_MAX, 127 .owner = THIS_MODULE, 128 }; 129 130 int __init nft_range_module_init(void) 131 { 132 return nft_register_expr(&nft_range_type); 133 } 134 135 void nft_range_module_exit(void) 136 { 137 nft_unregister_expr(&nft_range_type); 138 } 139