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 priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 88 priv->len = desc.len; 89 return 0; 90 } 91 92 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) 93 { 94 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 95 96 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 97 goto nla_put_failure; 98 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) 99 goto nla_put_failure; 100 101 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 102 NFT_DATA_VALUE, priv->len) < 0) 103 goto nla_put_failure; 104 return 0; 105 106 nla_put_failure: 107 return -1; 108 } 109 110 static const struct nft_expr_ops nft_cmp_ops = { 111 .type = &nft_cmp_type, 112 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 113 .eval = nft_cmp_eval, 114 .init = nft_cmp_init, 115 .dump = nft_cmp_dump, 116 }; 117 118 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 119 const struct nft_expr *expr, 120 const struct nlattr * const tb[]) 121 { 122 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 123 struct nft_data_desc desc; 124 struct nft_data data; 125 u32 mask; 126 int err; 127 128 err = nft_data_init(NULL, &data, sizeof(data), &desc, 129 tb[NFTA_CMP_DATA]); 130 BUG_ON(err < 0); 131 132 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 133 err = nft_validate_register_load(priv->sreg, desc.len); 134 if (err < 0) 135 return err; 136 137 desc.len *= BITS_PER_BYTE; 138 mask = nft_cmp_fast_mask(desc.len); 139 140 priv->data = data.data[0] & mask; 141 priv->len = desc.len; 142 return 0; 143 } 144 145 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) 146 { 147 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 148 struct nft_data data; 149 150 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 151 goto nla_put_failure; 152 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) 153 goto nla_put_failure; 154 155 data.data[0] = priv->data; 156 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 157 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 158 goto nla_put_failure; 159 return 0; 160 161 nla_put_failure: 162 return -1; 163 } 164 165 const struct nft_expr_ops nft_cmp_fast_ops = { 166 .type = &nft_cmp_type, 167 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 168 .eval = NULL, /* inlined */ 169 .init = nft_cmp_fast_init, 170 .dump = nft_cmp_fast_dump, 171 }; 172 173 static const struct nft_expr_ops * 174 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 175 { 176 struct nft_data_desc desc; 177 struct nft_data data; 178 enum nft_cmp_ops op; 179 int err; 180 181 if (tb[NFTA_CMP_SREG] == NULL || 182 tb[NFTA_CMP_OP] == NULL || 183 tb[NFTA_CMP_DATA] == NULL) 184 return ERR_PTR(-EINVAL); 185 186 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 187 switch (op) { 188 case NFT_CMP_EQ: 189 case NFT_CMP_NEQ: 190 case NFT_CMP_LT: 191 case NFT_CMP_LTE: 192 case NFT_CMP_GT: 193 case NFT_CMP_GTE: 194 break; 195 default: 196 return ERR_PTR(-EINVAL); 197 } 198 199 err = nft_data_init(NULL, &data, sizeof(data), &desc, 200 tb[NFTA_CMP_DATA]); 201 if (err < 0) 202 return ERR_PTR(err); 203 204 if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) 205 return &nft_cmp_fast_ops; 206 else 207 return &nft_cmp_ops; 208 } 209 210 struct nft_expr_type nft_cmp_type __read_mostly = { 211 .name = "cmp", 212 .select_ops = nft_cmp_select_ops, 213 .policy = nft_cmp_policy, 214 .maxattr = NFTA_CMP_MAX, 215 .owner = THIS_MODULE, 216 }; 217