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 if (err < 0) 83 return err; 84 85 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 86 err = nft_validate_register_load(priv->sreg, desc.len); 87 if (err < 0) 88 return err; 89 90 priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 91 priv->len = desc.len; 92 return 0; 93 } 94 95 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) 96 { 97 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 98 99 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 100 goto nla_put_failure; 101 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) 102 goto nla_put_failure; 103 104 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 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 const struct nft_expr_ops nft_cmp_ops = { 114 .type = &nft_cmp_type, 115 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 116 .eval = nft_cmp_eval, 117 .init = nft_cmp_init, 118 .dump = nft_cmp_dump, 119 }; 120 121 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 122 const struct nft_expr *expr, 123 const struct nlattr * const tb[]) 124 { 125 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 126 struct nft_data_desc desc; 127 struct nft_data data; 128 u32 mask; 129 int err; 130 131 err = nft_data_init(NULL, &data, sizeof(data), &desc, 132 tb[NFTA_CMP_DATA]); 133 if (err < 0) 134 return err; 135 136 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 137 err = nft_validate_register_load(priv->sreg, desc.len); 138 if (err < 0) 139 return err; 140 141 desc.len *= BITS_PER_BYTE; 142 mask = nft_cmp_fast_mask(desc.len); 143 144 priv->data = data.data[0] & mask; 145 priv->len = desc.len; 146 return 0; 147 } 148 149 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) 150 { 151 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 152 struct nft_data data; 153 154 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 155 goto nla_put_failure; 156 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) 157 goto nla_put_failure; 158 159 data.data[0] = priv->data; 160 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 161 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 162 goto nla_put_failure; 163 return 0; 164 165 nla_put_failure: 166 return -1; 167 } 168 169 const struct nft_expr_ops nft_cmp_fast_ops = { 170 .type = &nft_cmp_type, 171 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 172 .eval = NULL, /* inlined */ 173 .init = nft_cmp_fast_init, 174 .dump = nft_cmp_fast_dump, 175 }; 176 177 static const struct nft_expr_ops * 178 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 179 { 180 struct nft_data_desc desc; 181 struct nft_data data; 182 enum nft_cmp_ops op; 183 int err; 184 185 if (tb[NFTA_CMP_SREG] == NULL || 186 tb[NFTA_CMP_OP] == NULL || 187 tb[NFTA_CMP_DATA] == NULL) 188 return ERR_PTR(-EINVAL); 189 190 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 191 switch (op) { 192 case NFT_CMP_EQ: 193 case NFT_CMP_NEQ: 194 case NFT_CMP_LT: 195 case NFT_CMP_LTE: 196 case NFT_CMP_GT: 197 case NFT_CMP_GTE: 198 break; 199 default: 200 return ERR_PTR(-EINVAL); 201 } 202 203 err = nft_data_init(NULL, &data, sizeof(data), &desc, 204 tb[NFTA_CMP_DATA]); 205 if (err < 0) 206 return ERR_PTR(err); 207 208 if (desc.type != NFT_DATA_VALUE) { 209 err = -EINVAL; 210 goto err1; 211 } 212 213 if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) 214 return &nft_cmp_fast_ops; 215 216 return &nft_cmp_ops; 217 err1: 218 nft_data_release(&data, desc.type); 219 return ERR_PTR(-EINVAL); 220 } 221 222 struct nft_expr_type nft_cmp_type __read_mostly = { 223 .name = "cmp", 224 .select_ops = nft_cmp_select_ops, 225 .policy = nft_cmp_policy, 226 .maxattr = NFTA_CMP_MAX, 227 .owner = THIS_MODULE, 228 }; 229