1 /* 2 * Copyright (c) 2008-2009 Patrick McHardy <[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 * 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_cmp_expr { 21 struct nft_data data; 22 enum nft_registers sreg:8; 23 u8 len; 24 enum nft_cmp_ops op:8; 25 }; 26 27 static void nft_cmp_eval(const struct nft_expr *expr, 28 struct nft_data data[NFT_REG_MAX + 1], 29 const struct nft_pktinfo *pkt) 30 { 31 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 32 int d; 33 34 d = nft_data_cmp(&data[priv->sreg], &priv->data, priv->len); 35 switch (priv->op) { 36 case NFT_CMP_EQ: 37 if (d != 0) 38 goto mismatch; 39 break; 40 case NFT_CMP_NEQ: 41 if (d == 0) 42 goto mismatch; 43 break; 44 case NFT_CMP_LT: 45 if (d == 0) 46 goto mismatch; 47 case NFT_CMP_LTE: 48 if (d > 0) 49 goto mismatch; 50 break; 51 case NFT_CMP_GT: 52 if (d == 0) 53 goto mismatch; 54 case NFT_CMP_GTE: 55 if (d < 0) 56 goto mismatch; 57 break; 58 } 59 return; 60 61 mismatch: 62 data[NFT_REG_VERDICT].verdict = NFT_BREAK; 63 } 64 65 static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { 66 [NFTA_CMP_SREG] = { .type = NLA_U32 }, 67 [NFTA_CMP_OP] = { .type = NLA_U32 }, 68 [NFTA_CMP_DATA] = { .type = NLA_NESTED }, 69 }; 70 71 static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 72 const struct nlattr * const tb[]) 73 { 74 struct nft_cmp_expr *priv = nft_expr_priv(expr); 75 struct nft_data_desc desc; 76 int err; 77 78 priv->sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); 79 priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 80 81 err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]); 82 BUG_ON(err < 0); 83 84 priv->len = desc.len; 85 return 0; 86 } 87 88 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) 89 { 90 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 91 92 if (nla_put_be32(skb, NFTA_CMP_SREG, htonl(priv->sreg))) 93 goto nla_put_failure; 94 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) 95 goto nla_put_failure; 96 97 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 98 NFT_DATA_VALUE, priv->len) < 0) 99 goto nla_put_failure; 100 return 0; 101 102 nla_put_failure: 103 return -1; 104 } 105 106 static struct nft_expr_type nft_cmp_type; 107 static const struct nft_expr_ops nft_cmp_ops = { 108 .type = &nft_cmp_type, 109 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 110 .eval = nft_cmp_eval, 111 .init = nft_cmp_init, 112 .dump = nft_cmp_dump, 113 }; 114 115 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 116 const struct nft_expr *expr, 117 const struct nlattr * const tb[]) 118 { 119 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 120 struct nft_data_desc desc; 121 struct nft_data data; 122 u32 mask; 123 int err; 124 125 priv->sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); 126 127 err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); 128 BUG_ON(err < 0); 129 desc.len *= BITS_PER_BYTE; 130 131 mask = nft_cmp_fast_mask(desc.len); 132 priv->data = data.data[0] & mask; 133 priv->len = desc.len; 134 return 0; 135 } 136 137 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) 138 { 139 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 140 struct nft_data data; 141 142 if (nla_put_be32(skb, NFTA_CMP_SREG, htonl(priv->sreg))) 143 goto nla_put_failure; 144 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) 145 goto nla_put_failure; 146 147 data.data[0] = priv->data; 148 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 149 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 150 goto nla_put_failure; 151 return 0; 152 153 nla_put_failure: 154 return -1; 155 } 156 157 const struct nft_expr_ops nft_cmp_fast_ops = { 158 .type = &nft_cmp_type, 159 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 160 .eval = NULL, /* inlined */ 161 .init = nft_cmp_fast_init, 162 .dump = nft_cmp_fast_dump, 163 }; 164 165 static const struct nft_expr_ops * 166 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 167 { 168 struct nft_data_desc desc; 169 struct nft_data data; 170 enum nft_registers sreg; 171 enum nft_cmp_ops op; 172 int err; 173 174 if (tb[NFTA_CMP_SREG] == NULL || 175 tb[NFTA_CMP_OP] == NULL || 176 tb[NFTA_CMP_DATA] == NULL) 177 return ERR_PTR(-EINVAL); 178 179 sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); 180 err = nft_validate_input_register(sreg); 181 if (err < 0) 182 return ERR_PTR(err); 183 184 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 185 switch (op) { 186 case NFT_CMP_EQ: 187 case NFT_CMP_NEQ: 188 case NFT_CMP_LT: 189 case NFT_CMP_LTE: 190 case NFT_CMP_GT: 191 case NFT_CMP_GTE: 192 break; 193 default: 194 return ERR_PTR(-EINVAL); 195 } 196 197 err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); 198 if (err < 0) 199 return ERR_PTR(err); 200 201 if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) 202 return &nft_cmp_fast_ops; 203 else 204 return &nft_cmp_ops; 205 } 206 207 static struct nft_expr_type nft_cmp_type __read_mostly = { 208 .name = "cmp", 209 .select_ops = nft_cmp_select_ops, 210 .policy = nft_cmp_policy, 211 .maxattr = NFTA_CMP_MAX, 212 .owner = THIS_MODULE, 213 }; 214 215 int __init nft_cmp_module_init(void) 216 { 217 return nft_register_expr(&nft_cmp_type); 218 } 219 220 void nft_cmp_module_exit(void) 221 { 222 nft_unregister_expr(&nft_cmp_type); 223 } 224