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 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 regs->verdict.code = 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 err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc, 79 tb[NFTA_CMP_DATA]); 80 BUG_ON(err < 0); 81 82 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 83 err = nft_validate_register_load(priv->sreg, desc.len); 84 if (err < 0) 85 return err; 86 87 if (desc.len > U8_MAX) 88 return -ERANGE; 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 struct nft_expr_type nft_cmp_type; 114 static const struct nft_expr_ops nft_cmp_ops = { 115 .type = &nft_cmp_type, 116 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 117 .eval = nft_cmp_eval, 118 .init = nft_cmp_init, 119 .dump = nft_cmp_dump, 120 }; 121 122 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 123 const struct nft_expr *expr, 124 const struct nlattr * const tb[]) 125 { 126 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 127 struct nft_data_desc desc; 128 struct nft_data data; 129 u32 mask; 130 int err; 131 132 err = nft_data_init(NULL, &data, sizeof(data), &desc, 133 tb[NFTA_CMP_DATA]); 134 BUG_ON(err < 0); 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.len <= sizeof(u32) && op == NFT_CMP_EQ) 209 return &nft_cmp_fast_ops; 210 else 211 return &nft_cmp_ops; 212 } 213 214 static struct nft_expr_type nft_cmp_type __read_mostly = { 215 .name = "cmp", 216 .select_ops = nft_cmp_select_ops, 217 .policy = nft_cmp_policy, 218 .maxattr = NFTA_CMP_MAX, 219 .owner = THIS_MODULE, 220 }; 221 222 int __init nft_cmp_module_init(void) 223 { 224 return nft_register_expr(&nft_cmp_type); 225 } 226 227 void nft_cmp_module_exit(void) 228 { 229 nft_unregister_expr(&nft_cmp_type); 230 } 231