1 /* 2 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> 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_regs *regs, 29 const struct nft_pktinfo *pkt) 30 { 31 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 32 int d; 33 34 d = memcmp(®s->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 /* fall through */ 48 case NFT_CMP_LTE: 49 if (d > 0) 50 goto mismatch; 51 break; 52 case NFT_CMP_GT: 53 if (d == 0) 54 goto mismatch; 55 /* fall through */ 56 case NFT_CMP_GTE: 57 if (d < 0) 58 goto mismatch; 59 break; 60 } 61 return; 62 63 mismatch: 64 regs->verdict.code = NFT_BREAK; 65 } 66 67 static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { 68 [NFTA_CMP_SREG] = { .type = NLA_U32 }, 69 [NFTA_CMP_OP] = { .type = NLA_U32 }, 70 [NFTA_CMP_DATA] = { .type = NLA_NESTED }, 71 }; 72 73 static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 74 const struct nlattr * const tb[]) 75 { 76 struct nft_cmp_expr *priv = nft_expr_priv(expr); 77 struct nft_data_desc desc; 78 int err; 79 80 err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc, 81 tb[NFTA_CMP_DATA]); 82 BUG_ON(err < 0); 83 84 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 85 err = nft_validate_register_load(priv->sreg, desc.len); 86 if (err < 0) 87 return err; 88 89 priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 90 priv->len = desc.len; 91 return 0; 92 } 93 94 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) 95 { 96 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 97 98 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 99 goto nla_put_failure; 100 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) 101 goto nla_put_failure; 102 103 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 104 NFT_DATA_VALUE, priv->len) < 0) 105 goto nla_put_failure; 106 return 0; 107 108 nla_put_failure: 109 return -1; 110 } 111 112 static const struct nft_expr_ops nft_cmp_ops = { 113 .type = &nft_cmp_type, 114 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 115 .eval = nft_cmp_eval, 116 .init = nft_cmp_init, 117 .dump = nft_cmp_dump, 118 }; 119 120 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 121 const struct nft_expr *expr, 122 const struct nlattr * const tb[]) 123 { 124 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 125 struct nft_data_desc desc; 126 struct nft_data data; 127 u32 mask; 128 int err; 129 130 err = nft_data_init(NULL, &data, sizeof(data), &desc, 131 tb[NFTA_CMP_DATA]); 132 BUG_ON(err < 0); 133 134 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 135 err = nft_validate_register_load(priv->sreg, desc.len); 136 if (err < 0) 137 return err; 138 139 desc.len *= BITS_PER_BYTE; 140 mask = nft_cmp_fast_mask(desc.len); 141 142 priv->data = data.data[0] & mask; 143 priv->len = desc.len; 144 return 0; 145 } 146 147 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) 148 { 149 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 150 struct nft_data data; 151 152 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 153 goto nla_put_failure; 154 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) 155 goto nla_put_failure; 156 157 data.data[0] = priv->data; 158 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 159 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 160 goto nla_put_failure; 161 return 0; 162 163 nla_put_failure: 164 return -1; 165 } 166 167 const struct nft_expr_ops nft_cmp_fast_ops = { 168 .type = &nft_cmp_type, 169 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 170 .eval = NULL, /* inlined */ 171 .init = nft_cmp_fast_init, 172 .dump = nft_cmp_fast_dump, 173 }; 174 175 static const struct nft_expr_ops * 176 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 177 { 178 struct nft_data_desc desc; 179 struct nft_data data; 180 enum nft_cmp_ops op; 181 int err; 182 183 if (tb[NFTA_CMP_SREG] == NULL || 184 tb[NFTA_CMP_OP] == NULL || 185 tb[NFTA_CMP_DATA] == NULL) 186 return ERR_PTR(-EINVAL); 187 188 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 189 switch (op) { 190 case NFT_CMP_EQ: 191 case NFT_CMP_NEQ: 192 case NFT_CMP_LT: 193 case NFT_CMP_LTE: 194 case NFT_CMP_GT: 195 case NFT_CMP_GTE: 196 break; 197 default: 198 return ERR_PTR(-EINVAL); 199 } 200 201 err = nft_data_init(NULL, &data, sizeof(data), &desc, 202 tb[NFTA_CMP_DATA]); 203 if (err < 0) 204 return ERR_PTR(err); 205 206 if (desc.type != NFT_DATA_VALUE) { 207 err = -EINVAL; 208 goto err1; 209 } 210 211 if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) 212 return &nft_cmp_fast_ops; 213 214 return &nft_cmp_ops; 215 err1: 216 nft_data_release(&data, desc.type); 217 return ERR_PTR(-EINVAL); 218 } 219 220 struct nft_expr_type nft_cmp_type __read_mostly = { 221 .name = "cmp", 222 .select_ops = nft_cmp_select_ops, 223 .policy = nft_cmp_policy, 224 .maxattr = NFTA_CMP_MAX, 225 .owner = THIS_MODULE, 226 }; 227