1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> 4 * 5 * Development of this code funded by Astaro AG (http://www.astaro.com/) 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/init.h> 10 #include <linux/module.h> 11 #include <linux/netlink.h> 12 #include <linux/netfilter.h> 13 #include <linux/netfilter/nf_tables.h> 14 #include <net/netfilter/nf_tables_core.h> 15 #include <net/netfilter/nf_tables.h> 16 17 struct nft_cmp_expr { 18 struct nft_data data; 19 enum nft_registers sreg:8; 20 u8 len; 21 enum nft_cmp_ops op:8; 22 }; 23 24 void nft_cmp_eval(const struct nft_expr *expr, 25 struct nft_regs *regs, 26 const struct nft_pktinfo *pkt) 27 { 28 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 29 int d; 30 31 d = memcmp(®s->data[priv->sreg], &priv->data, priv->len); 32 switch (priv->op) { 33 case NFT_CMP_EQ: 34 if (d != 0) 35 goto mismatch; 36 break; 37 case NFT_CMP_NEQ: 38 if (d == 0) 39 goto mismatch; 40 break; 41 case NFT_CMP_LT: 42 if (d == 0) 43 goto mismatch; 44 /* fall through */ 45 case NFT_CMP_LTE: 46 if (d > 0) 47 goto mismatch; 48 break; 49 case NFT_CMP_GT: 50 if (d == 0) 51 goto mismatch; 52 /* fall through */ 53 case NFT_CMP_GTE: 54 if (d < 0) 55 goto mismatch; 56 break; 57 } 58 return; 59 60 mismatch: 61 regs->verdict.code = NFT_BREAK; 62 } 63 64 static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { 65 [NFTA_CMP_SREG] = { .type = NLA_U32 }, 66 [NFTA_CMP_OP] = { .type = NLA_U32 }, 67 [NFTA_CMP_DATA] = { .type = NLA_NESTED }, 68 }; 69 70 static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 71 const struct nlattr * const tb[]) 72 { 73 struct nft_cmp_expr *priv = nft_expr_priv(expr); 74 struct nft_data_desc desc; 75 int err; 76 77 err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc, 78 tb[NFTA_CMP_DATA]); 79 if (err < 0) 80 return err; 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 if (err < 0) 131 return err; 132 133 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 134 err = nft_validate_register_load(priv->sreg, desc.len); 135 if (err < 0) 136 return err; 137 138 desc.len *= BITS_PER_BYTE; 139 mask = nft_cmp_fast_mask(desc.len); 140 141 priv->data = data.data[0] & mask; 142 priv->len = desc.len; 143 return 0; 144 } 145 146 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) 147 { 148 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 149 struct nft_data data; 150 151 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 152 goto nla_put_failure; 153 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) 154 goto nla_put_failure; 155 156 data.data[0] = priv->data; 157 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 158 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 159 goto nla_put_failure; 160 return 0; 161 162 nla_put_failure: 163 return -1; 164 } 165 166 const struct nft_expr_ops nft_cmp_fast_ops = { 167 .type = &nft_cmp_type, 168 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 169 .eval = NULL, /* inlined */ 170 .init = nft_cmp_fast_init, 171 .dump = nft_cmp_fast_dump, 172 }; 173 174 static const struct nft_expr_ops * 175 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 176 { 177 struct nft_data_desc desc; 178 struct nft_data data; 179 enum nft_cmp_ops op; 180 int err; 181 182 if (tb[NFTA_CMP_SREG] == NULL || 183 tb[NFTA_CMP_OP] == NULL || 184 tb[NFTA_CMP_DATA] == NULL) 185 return ERR_PTR(-EINVAL); 186 187 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 188 switch (op) { 189 case NFT_CMP_EQ: 190 case NFT_CMP_NEQ: 191 case NFT_CMP_LT: 192 case NFT_CMP_LTE: 193 case NFT_CMP_GT: 194 case NFT_CMP_GTE: 195 break; 196 default: 197 return ERR_PTR(-EINVAL); 198 } 199 200 err = nft_data_init(NULL, &data, sizeof(data), &desc, 201 tb[NFTA_CMP_DATA]); 202 if (err < 0) 203 return ERR_PTR(err); 204 205 if (desc.type != NFT_DATA_VALUE) { 206 err = -EINVAL; 207 goto err1; 208 } 209 210 if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) 211 return &nft_cmp_fast_ops; 212 213 return &nft_cmp_ops; 214 err1: 215 nft_data_release(&data, desc.type); 216 return ERR_PTR(-EINVAL); 217 } 218 219 struct nft_expr_type nft_cmp_type __read_mostly = { 220 .name = "cmp", 221 .select_ops = nft_cmp_select_ops, 222 .policy = nft_cmp_policy, 223 .maxattr = NFTA_CMP_MAX, 224 .owner = THIS_MODULE, 225 }; 226